Patent Publication Number: US-10786759-B2

Title: Pump having an automated gas removal and fluid recovery system and method using a gas removal reservoir having an internal partition

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of application Ser. No. 14/473,086 filed on Aug. 29, 2014 which is a continuation-in-part of application Ser. No. 14/202,831 filed on Mar. 10, 2014, entitled PUMP HAVING AN AUTOMATED GAS REMOVAL AND FLUID RECOVERY SYSTEM AND METHOD, which claims the benefit of 35 U.S.C. § 119(e) of Provisional Application Ser. No. 61/789,217 filed on Mar. 15, 2013 entitled PUMP HAVING A QUICK CHANGE MOTOR DRIVE SYSTEM and all of whose entire disclosures are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to apparatus used in metering fluids with high precision, particularly in fields such as semiconductor manufacturing. 
     Many of the chemicals used in manufacturing integrated circuits, photomasks, and other devices with very small structures are corrosive, toxic and expensive. One example is photoresist, which is used in photolithographic processes. In such applications, both the rate and amount of a chemical in liquid phase—also referred to as process fluid or “chemistry”—that is dispensed onto a substrate must be very accurately controlled to ensure uniform application of the chemical and to avoid waste and unnecessary consumption. Furthermore, purity of the process fluid is often critical. Even the smallest foreign particles contaminating a process fluid cause defects in the very small structures formed during such processes. The process fluid must, therefore, be handled by a dispensing system in a manner that avoids contamination. See, for example, Semiconductor Equipment and Material International, “SEMI E49.2-0298 Guide for High Purity Deionized Water and Chemical Distribution Systems in Semiconductor Manufacturing Equipment” (1998). Improper handling can also result in introduction of gas bubbles and damage the chemistry. For these reasons, specialized systems are required for storing and metering fluids in photolithography and other processes used in fabrication of devices with very small structures. 
     Chemical distribution systems for these types of applications therefore must employ a mechanism for pumping process fluid in a way that permits finely controlled metering of the fluid and avoids contaminating and/or reacting with the process fluid. Generally, a pump pressurizes process fluid in a line to a dispense point. The fluid is drawn from a source that stores the fluid, such as a bottle or other container. The dispense point can be a small nozzle or other opening. The line from the pump to a dispense point on a manufacturing line is opened and closed with a valve. The valve can be placed at the dispense point. Opening the valve allows process fluid to flow at the point of dispense. A programmable controller operates the pumps and valves. All surfaces within the pumping mechanism, lines and valves that touch the process fluid must not react with or contaminate the process fluid. The pumps, containers of process fluid, and associated valving are sometimes stored in a cabinet that also house a controller. 
     Pumps for these types of systems are typically some form of a positive displacement type of pump, in which the size of a pumping chamber is enlarged to draw in fluid into the chamber, and then reduced to push it out. Types of positive displacement pumps that have been used include hydraulically actuated diaphragm pumps, bellows type pumps, piston actuated, rolling diaphragm pumps, and pressurized reservoir type pumping systems. U.S. Pat. No. 4,950,134 (Bailey et al.) is an example of a typical pump. It has an inlet, an outlet, a stepper motor and a fluid displacement diaphragm. When the pump is commanded electrically to dispense, the outlet valve opens and the motor turns to force flow of a displacement or actuating fluid into the actuating fluid chamber, resulting in the diaphragm moving to reduce the size the pumping chamber. Movement of the diaphragm forces process fluid out the pumping chamber and through the outlet valve. 
     Due to concerns over contamination, current practice in the semiconductor manufacturing industry is to use a pump only for pumping a single type of processing fluid or “chemistry.” In order to change chemistries being pumped, all of the surfaces contacting the processing fluid have to be changed. Depending on the design of the pump, this tends to be cumbersome and expensive, or simply not feasible. It is not uncommon to see processing systems that use up to 50 pumps in today&#39;s fabrication facilities. 
     A dispensing apparatus that supplies process chemicals from different sources is shown in U.S. Pat. No. 6,797,063 (Mekias). Here, the dispensing apparatus has two or more process chambers inside of a control chamber. The volume of the process chambers increases or decreases by adding control fluid to or removing control fluid from the control chamber. The use of valving at the inlets and outlets of the process chambers, in combination with a pressurized fluid reservoir that controls fluid into and out of the control chamber controls the flow of dispensed fluid through the process chambers. 
     One highly desirable feature of a precision pump not heretofore known is the ability to separate and remove components of the pump for maintenance or repair without breaking into the process fluid flow lines that are attached to one or more pump chamber heads. This would include avoiding opening of any seals in the process fluid flowpath either into, through, or out of the pump. U.S. Pat. No. 8,317,493 (Laessle, et al.), assigned to the same Assignee, namely, Integrated Designs L.P., as the present invention, discloses a precision pump system having just such a feature. 
     However, where a new pump motor needs to replace an existing motor, there remains a need to provide for immediate pumping fluid restoration and balancing within the pump head and pumping chamber, while not interrupting the process fluid flow and while minimizing the loss of any process fluid. 
     All references cited herein are incorporated herein by reference in their entireties. 
     BRIEF SUMMARY OF THE INVENTION 
     An automated pump system for removing gas from a process fluid to be dispensed is disclosed. The pump system comprises: a gas removal reservoir having a process fluid therein: at least one vertical partition that separates the reservoir into at least two sub-reservoirs having a fluid channel positioned at a free end portion of the at least one vertical partition for permitting process fluid to pass between the at least two sub-reservoirs; a first inlet coupled to a remote process fluid source; an outlet; a second inlet coupled to a process fluid recirculation path coupled to a drain; and at least one vent coupled to the drain; a driving means (e.g., a piston cylinder arrangement, pumping chamber, etc.) indirectly coupled to the outlet for driving the process fluid into or out of the gas removal reservoir; valves coupled to the inlet and to the outlet for permitting process fluid flow into and out of the gas removal reservoir, and coupled to the at least one vent to remove gas out of the gas removal reservoir and into the drain, and coupled to the second inlet for recirculating process fluid away from the drain and into the gas removal reservoir; a sensor (e.g., a pressure sensor, etc.) for providing a signal corresponding to a parameter in the pump system related to the presence of gas in the gas removal reservoir; and a processor coupled to the driving means, to the sensor and to the valves, and wherein the processor uses the signal to automatically control the valves and the driving means to force any gas in the gas removal reservoir through the at least one vent and into the drain. 
     An automated pump system for removing gas from a process fluid to be dispensed is disclosed. The pump system comprises: a gas removal reservoir having a process fluid therein: at least one vertical partition that separates the reservoir into at least two sub-reservoirs having a fluid channel positioned at a free end portion of the at least one vertical partition for permitting process fluid to pass between the at least two sub-reservoirs; a first inlet; an outlet; a second inlet coupled to a process fluid recirculation path coupled to a drain; and at least one vent coupled to the drain; a driving means (e.g., a piston cylinder arrangement, pumping chamber, etc.) coupled to the first inlet for driving the process fluid into and out of the gas removal reservoir, the outlet being coupled to a filter; valves coupled to the first inlet and to the outlet for permitting process fluid flow into and out of the gas removal reservoir, and coupled to the at least one vent to remove gas out of the gas removal reservoir and into the drain, and coupled to the second inlet for recirculating process fluid away from said drain and into said gas removal reservoir; a sensor (e.g., a pressure sensor, etc.) for providing a signal corresponding to a parameter in the pump system related to the presence of gas in the gas removal reservoir; and a processor coupled to the driving means, to the sensor and to the valves, and wherein the processor uses the signal to automatically control the valves and the driving means to force any gas in the gas removal reservoir through the at least one vent and into the drain. 
     A method for automatically removing gas from a process fluid to be dispensed is disclosed. The method comprising: (a) providing a gas removal reservoir having a first inlet coupled to a remote process fluid source, an outlet and at least one vent coupled to a drain, and wherein the gas removal reservoir has at least one vertical partition therein to form at least two sub-reservoirs that are in fluid communication via a fluid channel positioned at a free end of the at least one vertical partition; (b) indirectly coupling a driving means (e.g., a piston cylinder arrangement, pumping, chamber, etc.) to the outlet for driving the process fluid between the at least two sub-reservoirs and around the free end of the at least one vertical partition and out of the gas removal reservoir, and wherein the driving means is coupled to a remote process fluid source; (c) coupling valves to the first inlet and to the outlet for permitting the process fluid to flow into and out of the gas removal reservoir and coupling a valve to the at least one vent to remove gas out of the gas removal reservoir and into the drain, and coupling a second inlet to a process fluid recirculation path that is coupled to the drain and wherein the gas removal reservoir, the driving means and the valves form a system; (d) disposing a sensor (e.g., a pressure sensor, etc.) in the system and wherein the sensor provides a signal corresponding to a system parameter related to the presence of a gas in the gas removal reservoir; and (e) automatically controlling the driving means and the valves based on the signal received from the sensor, and wherein the automatic control forces any gas in the gas removal reservoir through the at least one vent and into the drain. 
     A method for automatically removing gas from a process fluid to be dispensed is disclosed. The method comprises: (a) providing a gas removal reservoir having a first inlet coupled to a remote process fluid source, an outlet and at least one vent coupled to a drain, said gas removal reservoir having at least one vertical partition therein to form at least two sub-reservoirs that are in fluid communication via a fluid channel positioned at a free end of said at least one vertical partition, said outlet being coupled to a filter input; (b) coupling a driving means (e.g., a piston cylinder arrangement, pumping chamber, etc.) to an inlet of said gas removal reservoir for driving the process fluid between said at least two sub-reservoirs and around said free end of said at least one vertical partition and out of said gas removal reservoir; (c) coupling valves to said inlet and to said outlet for permitting the process fluid to flow into and out of said gas removal reservoir and coupling a valve to said at least one vent to remove gas out of said gas removal reservoir and into the drain, and coupling a second inlet to a process fluid recirculation path that is coupled to the drain and wherein said gas removal reservoir, said driving means and said valves form a system; (d) disposing a sensor (e.g., a pressure sensor, etc.) in said system and wherein said sensor provides a signal corresponding to a system parameter related to the presence of a gas in the gas removal reservoir; and (e) automatically controlling said driving means and said valves based on said signal received from said sensor, said automatic control forcing any gas in said gas removal reservoir through said at least one vent and into the drain. 
     A method for automatically evacuating gas from a process fluid to be dispensed is disclosed. The method comprises: (a) providing a gas removal reservoir having a first inlet coupled to a remote process fluid source, an outlet and at least one vent coupled to a drain; (b) indirectly coupling a piston and cylinder arrangement to the outlet for driving the process fluid into and out of the gas removal reservoir, wherein the step of indirectly coupling a piston and cylinder arrangement further comprises providing a pumping chamber that dispenses a process fluid and wherein the pumping chamber comprises a diaphragm that separates the pumping chamber into first and second chambers and wherein the first chamber is in fluid communication with the piston and cylinder arrangement through a first valve for receiving a pumping fluid therein and wherein the second chamber is in fluid communication with the gas removal reservoir and wherein the second chamber dispenses the precise amount of the process fluid to a pump outlet in accordance with a volume displacement applied from the pumping fluid in the first chamber via the diaphragm; (c) coupling a second valve between a second chamber output and a filter input, coupling a third valve between a filter output and a recirculation flow path back to the gas removal reservoir via a second inlet, coupling a fourth valve between a filter vent and the drain and coupling a fifth valve between the at least one vent and said drain; and wherein the gas removal reservoir, the driving means and the valves form a system; (d) disposing a sensor (e.g., a pressure sensor, etc.) in the system and wherein the sensor provides a signal corresponding to a system parameter related to the presence of a gas in the gas removal reservoir; and (e) automatically controlling the piston and cylinder arrangement and the valves based on the signal received from the sensor, wherein the automatic control implements a gas evacuation routine comprising: (f)(1) detecting that the piston is at a reference position; (f)(2) if the piston is at the reference position, opening the first, second and third valves to displace the piston at a predetermined rate (e.g., 0.1 mL/sec, etc.) to build up pressure and if the piston is not at the reference position to move to perform a recharge operation of the piston and cylinder arrangement until the reference position is achieved; (f)(3) repeating step (f)(2) until a predetermined gas evacuation pressure is reached (e.g., 15 psi, etc.) and a predetermined volume displacement (e.g., 1.2 mL) of process fluid has occurred; (f)(4) opening the fourth and fifth valves for a predetermined time interval; (f)(5) closing the first, second and third valves; and (f)(6) performing the recharge operation of the piston and cylinder arrangement. 
     A method for automatically evacuating gas from a process fluid to be dispensed as part of a recirculation process is disclosed. The method comprises: (a) providing a gas removal reservoir having a first inlet coupled to a remote process fluid source, an outlet and at least one vent coupled to a drain; (b) indirectly coupling a piston and cylinder arrangement to the outlet for driving the process fluid into and out of the gas removal reservoir, and wherein the step of indirectly coupling a piston and cylinder arrangement further comprises providing a pumping chamber that dispenses a process fluid and wherein the pumping chamber comprises a diaphragm that separates the pumping chamber into first and second chambers and wherein the first chamber is in fluid communication with the piston and cylinder arrangement through a first valve for receiving a pumping fluid therein and wherein the second chamber is in fluid communication with the gas removal reservoir and wherein the second chamber dispenses the precise amount of the process fluid to a pump outlet in accordance with a volume displacement applied from the pumping fluid in the first chamber via the diaphragm; (c) coupling a second valve between the outlet and an input to the second chamber, coupling a third valve between a second chamber output and a filter input, coupling a fourth valve between a filter output and a recirculation flow path back to the gas removal reservoir via a second inlet, coupling a fifth valve between a filter vent and the drain, coupling a sixth valve between the at least one vent and the drain, and coupling a recirculation valve between the filter vent and the recirculation flow path; the gas removal reservoir, the driving means and the valves forming a system; (d) disposing a sensor (e.g., a pressure sensor, etc.) in the system and wherein the sensor provides a signal corresponding to a system parameter related to the presence of a gas in the gas removal reservoir; and (e) automatically controlling the piston and cylinder arrangement and the valves based on the signal received from the sensor, wherein the automatic control implements a gas evacuation routine as part of a process fluid recirculation process comprising: (f)(1) detecting that the piston is at a reference position; (f)(2) if the piston is at the reference position, opening the first, second, third and fourth valves to displace piston at a predetermined rate (e.g., 0.1 mL/sec, etc.) to build up pressure and if the piston is not at the reference position to move to perform a recharge operation of the piston and cylinder arrangement until the reference position is achieved; (f)(3) repeating step (f)(2) until a predetermined gas evacuation pressure (e.g., 15 psi, etc.) is reached and a predetermined volume displacement (e.g., 1.2 mL) of process fluid has occurred; (f)(4) opening the fifth, sixth and recirculation valves for a predetermined time interval; (f)(5) closing the first, second, third and fourth valves; and (f)(6) performing the recharge operation of the piston and cylinder arrangement. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein: 
         FIG. 1  is a block diagram of the present invention coupled to an exemplary integrated circuit wafer fabrication process; 
         FIG. 2  are isometric views of the precision pump assembly of the present invention; 
         FIG. 3  is an exploded view of the precision pump assembly of the present invention; 
         FIG. 4  is an exploded view of the pump body; 
         FIG. 4A  is an isometric view of the pump body showing the side that forms the pumping fluid reservoir; 
         FIG. 4B  is an isometric view of the pump body showing the side that forms the pumping fluid chamber; 
         FIG. 5  are isometric views of the pump head and showing how it couples to the pump body; 
         FIG. 6  is an exploded view of the pump head; 
         FIG. 6A  is an isometric view of the pump head block showing the process fluid chamber side of the pump head block; 
         FIG. 6B  is an isometric view of the pump head block showing the gas removal reservoir (also referred to as the “gas removal reservoir”) and the side of the pump head block that mates with the valve plate; 
         FIG. 6C  diagrammatically shows the gas removal reservoir inlet; 
         FIG. 7  is an exploded view of the filter distribution block; 
         FIG. 7A  are front and back views of the assembled filter distribution block; 
         FIG. 8  is an exploded view of the motor drive system; 
         FIG. 8A  is a plan view of the piston; 
         FIG. 8B  is a cross-sectional view of the piston assembly taken along line  8 B- 8 B of  FIG. 8A   FIG. 9  are exploded and assembled views of the piston; 
         FIG. 10  is a cross-sectional view of the piston cylinder; 
         FIG. 11  are exploded and isometric views of the overall pump assembly; 
         FIG. 11A  is an isometric view of the pump assembly showing internals of the pump in phantom and with the outer cover removed showing the connections of the various flare fittings; 
         FIG. 12  is an exemplary electrical wire harness (also referred to as pigtail) for use in the electronics of the present invention; 
         FIG. 13  is an exemplary syringe device for coupling to the present invention for adding air into the pumping fluid reservoir during the motor drive system change; 
         FIG. 13A  is a block diagram of the remote monitoring, viewing and controlling (RMVC) subsystem pump interface using a web server; 
         FIG. 13B  is a block diagram of the RMVC subsystem pump interface of  FIG. 13A  but using power-over-Ethernet (POE); 
         FIG. 13C  is an exemplary web cam that can be used to view the pump and its vicinity over the RMVC using the web server in the system of  FIG. 13B ; 
         FIG. 13D  is a block diagram of the RMVC subsystem pump interface of  FIG. 13B  but using POE and WiFi; 
         FIG. 13E  is a block diagram of the network management module (NMM) interface; 
         FIG. 13F  is a block diagram of the pump controller motherboard interfaces; 
         FIG. 13G  is a block diagram of the Assignee&#39;s (Integrated Designs, L.P.) standard graphical user interface (GUI) for the pump; 
         FIG. 13H  is a block diagram of the Assignee&#39;s standard GUI modified for Ethernet input/output; 
         FIG. 13I  is a block diagram of the Assignee&#39;s standard GUI and pump over the Ethernet; 
         FIG. 13J  is a block diagram of the Assignee&#39;s preferred cross-platform GUI, served JAVA applet; 
         FIG. 13K  is a block diagram of the RMVC (also referred to as “Lynx”) which is a web-served cross platform GUI; 
         FIG. 13L  is a table showing the JAVA supported platforms for use with the preferred GUI; 
         FIG. 14  is a circuit schematic of a conventional stepper motor H-bridge; 
         FIG. 15  block diagram of another embodiment of the present invention coupled to an exemplary integrated circuit wafer fabrication process that provides valving for filter recirculation of trapped process fluid and for a gas removal reservoir nitrogen supply; 
         FIG. 15A  depicts a venturi circuit for use in the alternative embodiment of  FIG. 15  to support filter recirculation of trapped process fluid; 
         FIG. 15B  depicts a flow diagram for the filter vent recirculation process; 
         FIG. 16A  is a flow diagram for the Recirculation mode using the embodiment according  FIGS. 1-1A ; 
         FIG. 16B  is a flow diagram for the Recirculation mode using the embodiment according  FIG. 15 ; 
         FIG. 17  is a flow diagram for the Auto Balance mode; 
         FIG. 18  is a flow diagram for the Dispense and Recharge modes; 
         FIG. 19  is a flow diagram for the Precharge mode; 
         FIG. 20  is a flow diagram for the Purge to Vent mode; 
         FIG. 21  is a flow diagram for the Purge to Output mode; 
         FIG. 22  is a flow diagram for the Prime Filter Housing mode; 
         FIGS. 23A-23B  form a flow diagram for the Prime Filter Substrate mode; 
         FIGS. 24A-24B  are flow diagrams for the System Drain mode using a two-filter block design; 
         FIGS. 24C-24D  are flow diagrams for the System Drain mode using a four-valve filter block design; 
         FIG. 25A  is a flow diagram for the Out of the Box mode using a two-filter block design; 
         FIG. 25B  is a flow diagram for the Out of the Box mode using a four-filter block design; 
         FIG. 26  is the flow diagram for the Changing Drive Assembly mode; 
         FIGS. 27A-27B  form a flow diagram for the Gas in Filter Detection Algorithm; 
         FIGS. 28A-28B  form the flow diagram for the Gas in Piston Chamber Detection Algorithm; 
         FIGS. 29A-29B  form the flow diagram for the Gas Volume in Gas removal reservoir Detection Algorithm; 
         FIG. 30  is a block diagram of the major features of the present invention; 
         FIG. 31  depicts an alternative configuration of the pump of the present invention wherein the filter is located before the gas removal reservoir and the recirculation is located upstream of the filter; 
         FIG. 32  depicts another alternative configuration of the pump of the present invention wherein the filter is located after the gas removal reservoir and the recirculation is located either upstream of the gas removal reservoir or downstream of the gas removal reservoir; 
         FIG. 33  depicts another alternative configuration of the pump of the present invention wherein the filter is located before the gas removal reservoir and where the recirculation is located downstream of the filter; 
         FIG. 34A  depicts a first gas evacuation process (also referred to as “GASE5”) whereby pressure is built up within the pump system and then a quick vent is performed to evacuate any air in the system as used during a portion of the Recharge routine; 
         FIG. 34B  depicts a second gas evacuation process (also referred to as “GASE6”) whereby pressure is again built up within the pump system and then a quick vent is performed to evacuate any air in the system as used during a portion of the recirculation routine; 
         FIG. 35  depicts a further alternative configuration of the pump of the present invention wherein the gas removal reservoir (i.e., gas removal reservoir or gas removal reservoir) comprises at least one internal partition and wherein the filter block has been replaced with an integrated configuration; 
         FIG. 35A  depicts a functional diagram of the gas removal reservoir having an internal partition to facilitate the separation and removal of gas from the process fluid; 
         FIG. 35B  depicts a functional diagram of an alternative embodiment of the gas removal reservoir that uses a plurality of internal partitions to facilitate the separation and removal of gas from the process fluid; 
         FIG. 35C  depicts a venturi circuit for use in the alternative system configuration of  FIG. 34  to support filter recirculation of trapped process fluid; 
         FIGS. 36A-36D  depict different views of the alternative system embodiment that uses a gas removal reservoir with at least one internal partition and showing the precision pump and its corresponding electrical control box; 
         FIG. 37  is an exploded view depicting the internals of the pump of  FIGS. 36A-36D ; 
         FIGS. 38A-38B  depict opposite side perspective views of the pump head of the pump of  FIGS. 36A-36D ; 
         FIG. 38C  depicts the alignment for coupling the pump head with the pump assembly of  FIGS. 36A-36D ; 
         FIGS. 38D-38F  depict the coupling of the pump assembly and pump head of  FIGS. 36A-36D  in more detail. 
         FIG. 39  is an exploded view of the pump head of the pump of  FIGS. 36A-36D  depicting the internal components; 
         FIG. 40A  is an isometric view of the pump head block of the pump of  FIGS. 36A-36D  showing the process fluid chamber side of the block; 
         FIG. 40B  is an isometric view of the pump head block showing the valve side of the pump head block of the pump of  FIGS. 36A-36D  that mates with the valve plate; 
         FIG. 40C  is an enlarged perspective view of the pump head block of the pump of  FIGS. 36A-36D  diagrammatically showing the gas removal reservoir inlet; 
         FIG. 41  is a functional diagram showing how the pump head of the pump of  FIGS. 36A-36D  interfaces with the filter  42 ; 
         FIG. 42  depicts another embodiment of the pump system which utilizes a filter vent-to-source line flow path having an apex and vent positioned thereat for venting air bubbles; 
         FIG. 43  depicts a further embodiment of the pump system which utilizes a filter vent-to-source line flow path having an apex with a bubble sensor and valve positioned thereat and also includes a vent path back to the filter drain; and 
         FIG. 44  depicts a further pump system wherein the input to the gas removal reservoir is fed from the pumping chamber. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will be illustrated in more detail with reference to the following embodiments, but it should be understood that the present invention is not deemed to be limited thereto. 
     Referring now to the drawings, wherein like part numbers refer to like elements throughout the several views, there is shown a block diagram of an exemplary embodiment of the present invention  20  that uses a precision pump system. The present invention  20  may form a portion of an integrated circuit wafer fabrication process, by way of example only, for dispensing a precise amount of process fluid to the wafer fabrication. As shown in  FIG. 1 , the present invention  20  is coupled to fabrication equipment, e.g., a fabrication reservoir FR which in turn is connected to a BIB (“bag in bottle” which supplies process fluid to the fabrication reservoir); a vent/drain is connected to the fabrication reservoir FR via a valve, V FAB . 
     As shown in  FIGS. 1-2 , the present invention  20  comprises a precision pump system  22  which includes a motor drive system  24  (e.g., Allegro A3977SED stepper motor driver and Portescape PK264-E2.0A stepper motor) that drives a piston  26  within a piston cylinder or chamber  28 . The precision pump  22  drives a pumping fluid (e.g., ethylene glycol or any other similar liquid that comprises similar characteristics, such as vapor pressure, boiling point, etc. that remains in its liquid state during all aspects of present invention&#39;s operation). The pumping fluid is also referred to as the “working” fluid because of how it interacts with the piston  26  and the operation of the pump  20  as a whole. The pumping fluid is provided from a pumping fluid reservoir  32  (e.g., 33 mL capacity) associated with the precision pump system  22 . The pumping fluid is used to drive and deliver a process fluid (e.g., photoresist) to the exemplary wafer fabrication process. The process fluid is provided from a gas removal reservoir  30  (e.g., having an exemplary capacity of 33-34 mL). The process fluid is a premium fluid and minimizing its waste is one of the key features of the present invention  20  which is to deliver precise amounts (e.g., maximum of 11 mL) of this process fluid without wasting it. To accomplish this delivery of the process fluid, both the pumping fluid and the process fluid are delivered to a working chamber  34  that comprises a pumping chamber  34 A (e.g., 11-13 mL capacity) and a dispense chamber  34 B (e.g., 11-13 mL capacity, and also referred to as “process fluid chamber”) which are formed by the presence of a diaphragm  36  that divides the working chamber  34  into the two variable sized chambers  34 A/ 34 B. Thus, the two fluids do not come into contact with each other and when the piston  26  is pressurizing the pumping fluid within the pumping chamber  34 A, the corresponding pressure is conveyed through the diaphragm  36  to the process fluid present in the process fluid chamber  34 B. The process fluid is then conveyed to filter distribution block  40  which comprises a filter  42  for filtering the process fluid before dispensing it to the application. 
     It should be noted that a pump controller  38 , as will be discussed in detail later, controls a motor drive assembly  24 E for displacing the piston  26 ; the motor drives the piston  26  based on pressure readings of the piston chamber  28  using a pressure sensor PS. Since the pump controller  38  knows the rate at which the piston  26  moves, as well as the time required to displace a desired volume of fluid, the precise amount of fluid dispensed is known. 
     It should also be understood that the presence of the associated pumping fluid reservoir  32  and the gas removal reservoir  30  form two key elements of the present invention  20 . By having the pumping fluid reservoir associated with the precision pump  22 , the present invention  20  is able to accomplish a quick replacement of the motor drive system while the pump remains online during the switch out. In addition, by having the gas removal reservoir  30  associated with the precision pump  22 , dispensed process fluid contains no gas bubbles and hence the phrase “gas removal reservoir”  30 . These reservoirs also permit the quick priming of the precision pump  22  and the filter distribution block  40  for the newly-inserted motor drive  24 . It should be understood that the location of either of these two associated reservoirs  30 / 32  may be integrated within the pump assembly  22 A/pump head  22 B (see  FIG. 3 ), or may be external to either of those components. The important feature is the presence of each of these reservoirs  30 / 32  in close proximity to the present invention  20  permits the present invention  20  to perform advanced operations in a closed internal fluid loop with only a single piston and a single pumping stage. 
     It should be further understood that filling of the gas removal reservoir  30  from the fabrication reservoir FR can occur at the top of the gas removal reservoir  30  or at the bottom of the gas removal reservoir  30 , etc.  FIG. 1  depicts the gas removal reservoir  30  and filter  42  using orientation notation to show one alternative where fluid couplings to the top of those devices are being used. 
     A pump controller (e.g., a microprocessor, microcontroller, etc.; e.g., a Freescale MC9S12DG128CPVE microcontroller)  38  is coupled to the motor driven system  24 , as well as each of the valves  1 - 12  to achieve the precise delivery of the process. By way of example only, the valves  1 - 8  and  10 - 12  may comprise diaphragmatic type valves (which are also referred to as diaphragmatic integrated valves, DIVs); valve  9  is a digital valve rather than a diaphragmatic valve. A bleed port valve BP 1  is provided with the pumping fluid reservoir  32  and a bleed port valve BP 2  is provided with the pumping chamber  34 A; the importance of those valves will be discussed later. In addition, a pressure sensor PS is provided for detecting the pressure within the piston cylinder  28  as will also be discussed later. Operation of these diaphragmatic valves are discussed below under Diaphragmatic Integrated Valves. It should be further noted that control of the valves pertaining to the gas removal reservoir  30  and the pumping fluid reservoir  32  by the microcontroller  38  is not limited to an integrated controller within the pump system  20 . It is within the broadest scope of the invention to include a remote controller of the valves associated with those two reservoirs. 
     Another key aspect of the present invention  20  is the ability to monitor, view and control the present invention  20  over a local area network (LAN), via wired (e.g., via an Ethernet connection, etc.) or wireless connection (e.g., Bluetooth, IEEE 802.11, etc.). This is accomplished via a network management module (NMM)  50 , which includes, among other things, a web server microcontroller (e.g., Freescale MCF52235CAL60 microcontroller). As will be discussed in detail later, the NMM  50  permits the precision pump system  20  to be monitored remotely and in real-time, as well as, to permit remotely-controlling the system  20 . The remote location includes a display controlled by a graphical user interface (GUI) that allows the operator to remotely monitor, view and control the operation of the precision pump system  20 . This remote monitor, view and control subsystem is hereinafter referred to as the remote monitoring, viewing and controlling (RMVC) subsystem, which is discussed below under Remote Monitoring, Viewing and Controlling (RMVC) Subsystem. 
       FIG. 2  is an isometric view of the present invention  20  showing the precision pump system  22  and an electrical control box  23  which houses the electronics that control the pump  22 , including the microcontroller  38  and the NMM  50  discussed previously. 
       FIG. 3  depicts the internals of the pump system  22 . The filter distribution block  40  is mountable behind a front plate  25 . Besides a coupling on the front plate  25 , there is a maintenance button  25 A that is activated to initiate the motor drive  24  removal; in particular, activation of the maintenance button  25 A opens isolation valve  8 . As can be seen, the motor drive  24  sits atop a main pump assembly  22 A and the motor drive  24  can be released from the main pump assembly via the removal of four screws  24 A- 24 D which can most easily be seen in  FIG. 4 .  FIG. 3  depicts the pump body assembly  22 A, pump head  22 B, a pneumatic valve manifold  44 , a cover plate  46  (see  FIG. 4 ) to the pumping fluid reservoir  34 A ( FIG. 4B ) and a pressure sensor board  48  ( FIG. 11 ), which includes the pressure sensor PS (e.g., Honeywell ASDXRRX100PD2A5 digital pressure sensor) and a pressure sensor board microcontroller (e.g., Microchip PIC12F675-E/SN). 
     Pump Body  22 A 
     The precision pump system  20  incorporates a unique design of a single stage pump with the use of two associated reservoirs, namely, the gas removal reservoir  30  (also referred to as the “pre reservoir”) and the pumping fluid reservoir  32 , allowing the pumping fluid and the process fluid to be stored and accessed on an as needed basis. This allows the pump system  20  to perform operations in a closed internal fluid loop with only a single piston. A prior art closed loop system filled with and facilitating the movement of incompressible working fluid requires the increase and decrease using two or more pump stages to create an imbalance of pressure to induce flow. The decrease in the volume of one chamber must be equaled by the increase in volume of another connected chamber. The passively variable volume of the chambers (i.e.,  28 ,  34 A and  34 B) in the present pump system  20  allows for a partially closed system, the volume of the total sealed space is constant but the shape of the fluid filled portions of the pump can change with the amount of fluid contained in the particular chamber. 
     As shown in  FIG. 4 , the pump body  22 A comprises aluminum (by way of example only, machined to 6.15″x2.20″x2.20″). The front face  52 A features a machined slot  54  for an anti-rotation guide  56  on the piston  26  to travel in. Around this slot  54  are four threaded holes for mounting the pressure sensor PS and associated printed circuit board  48 , which also contains an infrared (IR) sensor that interfaces with the anti-rotation guide  56  on the piston  26 . This front face  52 A also features a tubing connection  58 A/ 58 B that taps into the piston chamber  28  inside the pump body  22 A. The other end of this tubing  60  ( FIG. 11 ) connects with the pressure sensor PS on the pressure sensor PCB  48 . This pressure sensor PS is used for calibration and balancing of the pumping fluid levels in the pump body  22 A. 
     On a left face  52 B of the pump body is the pumping fluid reservoir  32  (see  FIGS. 4 and 4A ) that is machined to house extra pumping fluid that is used in the maintenance operations of the pump  20 . There is an O-ring groove  115  machined around the perimeter of this chamber to allow an aluminum plate  46  to seal against this face  52 A of the pump body  22 A, thus completing the reservoir  32  for the pumping fluid. This sealing plate  46  is mounted to the pump with six screws  62  that secure into threaded holes around the perimeter of this face of the pump body  22 A. 
     The back face  52 C of the pump body  22 A includes the pumping fluid chamber  34 A (see  FIGS. 4 and 4B ) machined with an O-ring groove  63  ( FIG. 4B ), to seat an O-ring  65  ( FIG. 4 ), around the perimeter to properly seal the diaphragm  36  (e.g., a PTFE diaphragm, see  FIG. 4 ) against it with the use of a diaphragm hold down plate  64 . This aluminum diaphragm hold-down plate  64  has a cut-out in the center that mimics the shape of the process fluid chamber  34 B. This allows the diaphragm  36  to expand and contract through it while still having material over the O-rings to seal the diaphragm  36  to the pump body face  52 C. This back face  52 C of the pump body  22 A features eight threaded holes for the counter-sunk screws  66  that secure the diaphragm hold-down plate  64  to it. It also features six larger diameter screw holes for mounting the pump head  22 B (see  FIG. 5 ) into position on the face  52 C. There are through holes in both the hold-down plate  64  and the diaphragm  36  to accommodate the fourteen mounting screws required for the hold-down plate  64  and the pump head  22 B. At the top right of this back face  52 C, there is a threaded hole for a flow path that leads into the top of the pumping fluid reservoir  32 . This pathway acts as the bleed port, i.e., BP 1 , used in the motor change procedure and in balancing the pumping fluid levels in the pump  20 . Under normal operation (when the pumping fluid reservoir  32  is not in use), a screw BP 1  ( FIG. 4 ) is secured in this hole to seal the reservoir  32  from atmospheric pressure. 
     The right face  52 D ( FIG. 4 ) of the pump body  22 A only has one feature. This is an angled cutout  53  ( FIGS. 4 and 4B ) that features a threaded hole that feeds into a flow path to the top of the pumping fluid chamber  34 A. This acts as the bleed port BP 2  for the pumping fluid chamber  34 A. This threaded hole is sealed off by a screw  109 . This screw  109  does not be need to be removed for any user-performed maintenance. 
     The top face  52 E of the pump body  22 A features four threaded holes for the stepper motor  24  to be mounted with four bolts  24 A- 24 D. In the center of this face is a multi-diameter hole ( FIG. 10 ). The first and largest diameter (e.g., 1.505″) is machined to a depth of, for example, 0.25″ and is only necessary for the seating of the stepper motor  24 . The next diameter (e.g., 1.125″) is to provide clearance for the lead screw clamp and the anti-rotation guide  56  as they spin and travel within this hole, and is machined to a depth of 2.938″. The next diameter (0.75″) is the actual piston bore of the pump body  22 A, machined to a depth of, e.g., 5.188″. This has an 8 RMS finish with electroless nickel boron plating to improve the hardness and prevent wear from the piston and acts as the sealing face for the piston  26 . The bottom of this piston bore has a 60 degree chamfered edge to fit perfectly with the conical shape of the piston at its maximum stroke. The last diameter is 0.5″ and goes to a depth of approximately 5.875″. There are two flow paths that enter this final section. One leads to the front of the pump body  22 A and is connected to the pressure sensor PS on the pressure sensor PCB  48 . Off of this flow path another splits off to go to the isolation valve, valve  8 , on the bottom of the pump body  22 A that controls flow to the pumping fluid reservoir  32 . The second flow path from the final section goes directly to the other isolation valve, valve  5 , on the bottom face of the pump body  22 A that controls flow to the pumping fluid chamber  34 A. 
     The bottom face  52 F of the pump  22 A has two integrated valves ( 5  and  8 ) machined into it. These are designed similarly to the other diaphragmatic valves throughout the pump  22 A. Valve  8  controls flow between the piston chamber  28  and the pumping fluid reservoir  32  and valve  5  controls flow between the piston chamber  28  and the pumping fluid chamber  34 A. There is an aluminum valve plate  68  ( FIG. 4 ) that holds a PTFE diaphragm  70  ( FIG. 4 ) against the two O-rings  72  around the valve cutouts on the pump body  22 A. This aluminum valve plate  68  is secured to the pump body with  4  screws  72  ( FIG. 4 ). There are also four rubber mounting pads  74  ( FIG. 4 ) secured around the valve plate  68  to keep the pump body  22 A stable. 
     Isolation Valves V 5  and V 8   
     Isolation valves  5  and  8  are used in the pump system  20  to control the flow of the pumping fluid between the three pump fluid chambers  28 ,  32  and  34 A. The valves allow the pump  22  to store and access additional pumping fluid on an as needed basis. Since only one isolation valve is open at any given time, this arrangement insures that only one flow path from the piston chamber  28  is active at that same time. Flow from the piston chamber  28  to the pumping fluid reservoir  32  does not affect the pumping chamber  34 A and vice versa. 
     Reservoir for Incompressible Fluid Used in Motion Transfer 
     Fluid movement in a closed system filled entirely of incompressible fluid from one chamber to another requires the individual chamber volumes to be varied in conjunction with the fluid flow. It is impossible to adjust the normal holding volume of one chamber without directly and proportionally changing the normal holding volume of another. When this is desired, the only option is to incorporate an open system to allow the fluid volume to be altered. When a repeatable and reversible change in system volume is desired, the use of a reservoir allowing the fluid to be stored can be used to allow the fluid movement to and from the system while preventing any compressible fluids into the original system. 
     In order to allow the pump system  20  to perform maintenance functions with minimal physical disturbances to the pump  22  and pumped process fluid (e.g., photo chemical), a reservoir  32  for the incompressible fluid used in motion transfer, i.e., the pumping fluid, is incorporated into the pump body  22 A. This reservoir  32  is capable of storing volumes of temporarily unused pumping fluid. During various maintenance functions, the reservoir  32  is used to both temporarily store pumping fluid from the piston chamber  28  and to create a fluid barrier to prevent air bubble entrapment in the pumping fluid channels inside the pump body  22 A. 
     The pumping fluid reservoir  32  is connected to the piston chamber  28  through an integrated diaphragmatic valve,  8 . This valve  8  remains closed during the normal pumping process to prevent fluid movement into and out of the reservoir  32  to maintain a constant volume of pumping fluid used in the piston chamber  28  and pumping fluid chamber  34 A. During normal pumping processes the reservoir  32  simply stores pumping fluid that will be needed during the maintenance functions. The reservoir  32  is sealed from atmosphere by the pumping fluid reservoir bleed port screw BP 1  and is filled to roughly half capacity during normal pumping operations. The fluid in the reservoir  32  is exposed to the air sealed inside the reservoir  32 , but is unaffected by this gas due to the fluid&#39;s resistance to absorbing gas. 
     During maintenance processes, the reservoir bleed port screw BP 1  is removed to allow the ingress and egress of air from the reservoir  32 . This allows the pumping fluid levels to be altered while maintaining pressure equalization with atmospheric pressure. This ensures that no residual pressure differentials in the reservoir  32  will cause unwanted fluid flow to or from the rest of the pump  20 . After the completion of the maintenance function the pumping fluid reservoir bleed port screw BP 1  is re-installed to seal the reservoir  32 . 
     During a head auto-balancing process, the pumping fluid normally in the piston chamber  28  is dispensed into the pumping fluid reservoir  32  and the valve  8  isolating the pumping fluid reservoir fluid from the piston chamber  28  is then closed. This frees room in the piston chamber  28  to allow the piston  26  to move pumping fluid from the pumping fluid chamber  34 A as needed. Once the desired pumping fluid volume has been reached in the pumping fluid chamber  34 A, the valve  8  isolating the reservoir  32  opens, allowing the flow of pumping fluid from the reservoir  32  to the piston chamber  28 . As the piston  26  returns to the home position, the fluid flows from the reservoir  32  into the piston chamber  28 , completely refilling it. 
     During the drive assembly change, the valve V 8  isolating the reservoir  32  is opened allowing the pumping fluid normally held in the reservoir  32  to flow into the piston chamber  28 . This flow is caused by the suction created by the O-ring seal as the piston  26  is removed. The fact the fluid path from the pumping fluid reservoir  32  to the piston chamber  28  is attached to the bottom of the reservoir  32  means that only the pumping fluid flows in the fluid paths inside the pump unless the reservoir  32  is completely empty. This prevents any gaseous bubbles from entering the internal fluid paths and other pumping fluid chambers. 
     Drive Assembly 
     The motor drive assembly  24  ( FIG. 8 ) comprises a stepper motor  24 E, a bearing  24 F, a lead screw  24 G clamped onto the motor shaft by a clamp  24 H, and the piston  26  ( FIG. 9 ). During assembly, the bearing  24 F is pressed onto the stepper motor  24 E (e.g., using 80-90 PSI). The stainless steel lead screw  24 G is then installed onto the motor drive shaft and clamped into place. Grease is applied to the threads on the lead screw  24 G and the piston  26  is screwed on. The stepper motor  24 E is plugged into the pressure sensor PS PCB  48  that is mounted on the side of the pump body  22 A. 
     The piston ( FIGS. 8A-8B ) features two O-rings  74  ( FIG. 9 ) to keep the piston  26  properly aligned in the piston cylinder  28  of the pump body  22 A and to better retain grease along with a proper seal. The bottom face  76  ( FIG. 8 ) of the piston  26  is machined to be a conical shape. This shape aids in preventing air from being trapped in the piston cylinder  28  during initial assembly and during a drive change maintenance procedure. There is a piston wiper ring  77  ( FIG. 9 ) installed above the two O-rings  74  to keep debris out of the grease and the piston chamber  28 . An anti-rotation guide  56  is installed at the top of the piston  26  to serve as a restraint that keeps the piston  26  from turning as the motor  24 E turns the lead screw  24 G. The guide  56  travels in a machined slot  54  ( FIGS. 4 and 4A ) on the front face  52 A of the pump body  22 A. It is this anti-rotation guide  56  that converts the rotation motion of the piston  26  into reciprocating motion. This guide  56  also acts as a flag for the IR sensor mounted on the PCB  48  on the front face of the pump body  22 A. When this flag is in between the prongs of the IR sensor, the pump software in the microcontroller  38  knows the piston  26  is at the home position (HRP). 
     Conical Piston Shape to Displace Fluid and Bleed Air Out of the Piston Chamber During Insertion 
     The pump system  20  relies of the absence of air in the pumping fluid chamber  34 A to achieve highly repeatable and controllable dispenses. Air in the pumping fluid chamber  34 A expands and contracts to an unacceptable degree due to the pressure changes that occur during the dispense cycle. To ensure no air remains in the piston bore  28  after the drive assembly changing process, the use of a piston  26  with conically shaped end  76  is incorporated into the pump  20 . The addition of an inverted conical shape  76  to the piston  26  assures that any air is evacuated prior to the first O-ring sealing  74  with the piston bore. 
     When the piston  26  is to be reinserted into the piston bore  28  of the pump  22 A, the pumping fluid level inside the piston bore  28  is just below a horizontal plane formed by the uppermost circumference of the piston bore  28 . As the piston  26  is lowered into the piston bore  28 , the conical shape  76  of the piston end displaces a volume of the pumping fluid in the piston bore  28 . As the piston  26  lowers, the volume of displaced pumping fluid increases and causes the fluid level to rise in relation to the pump body  22 A. The volume of the conical shape of the piston end is greater than the volume of the air initially located above the pumping fluid and below the plane formed by the upper section of the piston bore  28 . Since the volume of displaced liquid is larger than the volume of air, the fluid rises to the point it fills the entire volume located below the O-ring sealing surface of the piston bore  28 . 
     The volume of the conical shape is sufficient to displace the air below the sealing surface, while not causing an undue amount of spillage from any excess pumping fluid being forced out of the piston bore  28 . The conical shape  76  is important to the evacuation of air since the angled face directs any bubbles already floating in the piston chamber  28  up and out of the piston bore  28 . The outward angle face of the conical piston works in conjunction with the buoyant nature of gas bubbles to evacuate all gasses from the volume sealed by the O-rings  74  against the piston bore  28 . 
     Pump Head  22 B 
     The pump head is depicted in detail in  FIGS. 6-6C . The pump head ( FIG. 6 ) consists of a PTFE block  78  and an aluminum valve plate  80 . The PTFE block  78  contains the process fluid chamber  34 B on one face along with four diaphragmatic integrated valves ( 1 ,  2 ,  3 , and  7 ) and the gas removal reservoir  30  (also referred to as the “Gas removal reservoir”) on the opposite face. There are four flow paths in and out of the gas removal reservoir  30 , as shown in  FIGS. 1 and 1A . These flow paths connect to the process fluid source  10  (e.g., fabrication reservoir), the filter valve block  40 , and the process fluid chamber  34 B on the opposite face of the head PTFE block  78 . The process fluid chamber  34 B is cut into the face of the PTFE block  78  that interfaces with the pump body  22 A. This chamber  34 A is in the shape of an elongated rectangle with circular ends. There is a raised edge around this chamber to support an O-ring. The diaphragmatic valve cutouts on the opposite face of the PTFE block  78  are designed as those described in the Diaphragmatic Integrated Valves section below. As shown most clearly in  FIG. 6B , the gas removal reservoir  30  is cut into the same face as the valves  1 ,  2 ,  3  and  7 . It is shaped as a square but with one vertical edge longer than the other to create a high point in the chamber  30  that aids in bubble collection and venting. The process fluid source inlet is positioned on the roof of the gas removal reservoir where the side wall meets the roof on the shorter vertical side. The purpose of the source inlet&#39;s position is to allow for the process fluid to enter into the gas removal reservoir at an angle near the side edge which allows for the process fluid to smoothly run down the wall of the gas removal reservoir instead of dripping from the top of the reservoir, which can cause the capturing of air as the fluid falls. There is a raised edge around the reservoir  30  that is similar in profile to those that surround the integrated valves  1 ,  2 ,  3  and  7 . Four flow paths exit the PTFE block  78  through ¼″ male flare fittings on the top face. Two of these lines are connected to the filter valve block  40  and the other two go to the process fluid chamber  34 B and the process fluid source  10 . Four set screws  82  hold the male flare fittings securely in place in the block  78 .  FIG. 11  depicts how the pump head  22 B and the pump body  22 A are mated together. 
     The aluminum valve plate  80  ( FIG. 6 ) features four valve cutouts, mirrored to the valve cutouts on the corresponding surface  80 A ( FIG. 6B ) of the PTFE block  78 , and an O-ring cutout  30 A that lines up with the raised edge around the reservoir  30  on the PTFE block  78 . The valve cutouts on the aluminum plate  78  are designed similarly to those described in the diaphragmatic integrated valves section below. The aluminum valve plate  80  holds the O-rings for valves  1 ,  2 ,  3  and  7  as well as for the gas removal reservoir  30 . In between the aluminum valve plate  80  and the PTFE block  78 , there is a PTFE diaphragm  84  ( FIG. 6 ) similar to that described in the diaphragmatic integrated valves section below. The pieces are assembled and secured to the pump head using six screws  86  ( FIG. 6 ) that travel through the whole assembly and fasten to the pump body  22 A. 
     Diaphragmatic Integrated Valves 
     The present invention  20  is designed to take up minimal space to allow the customer to optimize the space available in the coater/developer where the pump  20  is installed. The valves used throughout the pump system play a major role in reducing its footprint. Off-the-shelf valves tend to take up too much space. The valves in the pump system of the present invention  20  are low profile diaphragm valves that are designed right into the pump head  22 B. The following discussion pertains to the diaphragmatic valves uses in the pump head  22 B, it being understood that diaphragmatic valves used elsewhere in the present invention have a similar construction. 
     The valves and associated flow paths are machined into the virgin PTFE block  78 , allowing the pump  20  to perform a variety of complex operations in a very small amount of space. 
     The basic diaphragmatic integrated valve design consists of three parts: a PTFE block, a PTFE diaphragm, and an aluminum plate. The PTFE block contains the flow paths and the circular valve chambers for the process fluid to flow through. The aluminum plate serves as a manifold to distribute the air required for the pneumatic actuation of the valves, having flow paths and circular chambers that mirror the valve chambers on the PTFE block. The PTFE diaphragm is the interface between the PTFE block and the aluminum plate and is forced into either the PTFE block&#39;s chambers or the aluminum plate&#39;s chambers by positive or negative pressure from the pneumatic lines, respectively. 
     The valve design on the PTFE block side involves a shallow circular cutout on the face of the block, and has both an inlet and outlet flow path that connect with this circular chamber. On the block face surrounding the circular cutout, there is a raised lip to provide a better sealing surface with the diaphragm against the aluminum plate. One of the two flow paths that intersect with the valve cutout is usually located near the center of the circle to allow the diaphragm to effectively seal the path when it is pushed into the valve cutout by pneumatic pressure from the other side. 
     The diaphragm is made of 0.01″ thick PTFE sheets and is cut to the size of the sealing face of the valve block. Any holes needed for mounting valve blocks are cut in the diaphragm sheet to allow bolts and screws to pass through. The thickness of the PTFE diaphragm allows it to be deformed by the pneumatic pressure and vacuum to fill the cutout chambers in the PTFE block and aluminum plate, respectively. 
     The aluminum plate is designed with circular cutouts on the face that mates with the valve face of the PTFE block. These cutouts are placed to mirror the cutouts on the PTFE block, creating a valve chamber that is bisected by the diaphragm when the parts are assembled. O-ring grooves are machined around the valve cutouts on the aluminum plate for the raised lips around each valve cutout on the PTFE block to seal against. Each valve cutout on the aluminum block interfaces with one flow path in which pressurized air travels through. The flow paths containing the pressurized air travel through the aluminum plate and are finished with a fitting that allows the connection of nylon tubing. This tubing is connected to a separate valve manifold with a bank of 3-way valves that control the application of either pressure or vacuum to each of the valves in the pump system individually. 
     To understand operation of the diaphragmatic valve,  FIGS. 6-6A  depict the construction of DIV valves  1 ,  2 ,  3  and  7 , it being understood that all of the DIV valves operate in a similar manner. As can be seen in  FIG. 6 , the control side of the DIV (e.g., valve  7 ) is on plate  80  which comprises a control port CP (e.g., an air port) surrounded by a channel CH into which an O-ring  81  is disposed. A diaphragm  84  is disposed in between plate  80  and surface  80 A of the block  78 . As can be seen in  FIG. 6B , surface  80 A of the block  78  comprises the “output” portion of the DIV  7  which comprises two outlet ports  83 A/ 83 B. Operation of the diaphragmatic valve involves connecting the control port to a pneumatic source where either a pressure or vacuum is applied. When pressure is applied, the diaphragm closes the two outlet ports and conversely when vacuum is applied the diaphragm opens the two outlet ports. 
     Gas Removal Reservoir&#39;s  30  Seal: 
     As shown most clearly in  FIG. 6 , the gas removal reservoir  30  is sealed by a PTFE diaphragm cover and a metal plate with an integrated O-ring groove on it. The gas removal reservoir  30  has a raised ridge providing support to the PTFE diaphragm cover around the edge for better sealing. The back metal plate provides uniform support to the gas removal reservoir PTFE diaphragm cover and ensures no leakage around the O-ring sealing. Table 1 is a definition of the various DIVs: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 DIV Valve Numbers and Description 
               
            
           
           
               
               
            
               
                 Diaphragmatic Integrated 
                   
               
               
                 Valve Number 
                 Diaphragmatic Integrated Valve Description 
               
               
                   
               
            
           
           
               
               
            
               
                 1 
                 Inlet-Gas removal reservoir 30 
               
               
                 2 
                 Outlet-Gas removal reservoir 30/Inlet-Pump 
               
               
                 3 
                 Outlet-Pump/Inlet-Filter 
               
               
                 4 
                 Recirculation Valve 
               
               
                 5 
                 Pumping Chamber 34A-Isolation Valve 
               
               
                 6 
                 Filter Vent/Drain 
               
               
                 7 
                 Gas removal reservoir 30-Drain 
               
               
                 8 
                 Pumping Fluid Reservoir 32-Isolation Valve 
               
               
                 9 
                 Digital valve (customer supplied) 
               
               
                 10 
                 Filter recirculation (see FIG. 15) 
               
               
                 11 
                 Internal Recirculation Shut-off (see FIG. 15) 
               
               
                 12 
                 Gas removal reservoir 30 N 2  Supply (see 
               
               
                   
                 FIG. 15) 
               
               
                   
               
            
           
         
       
     
     External Valve Block/Filter Block  40   
     The pump system  20  utilizes valves and valve controls to direct fluid flow during the various maintenance, startup, and operating processes. This must be achieved while maintaining the compact size of the pump required by the spaces in which they are mounted. To meet the aforementioned requirements, some of the diaphragmatic valves are included in a small external block ( FIG. 7 ). This block directs fluid flow to and from six connections  175  ( FIG. 7 ). The valve block includes connections from filter vent connection, from the filter fluid output line, to the external dispense digital valve, to the pump system drain line, from the gas removal reservoir vent line, and to the gas removal reservoir recirculation line. The fluid flow is controlled by four pneumatically-actuated integrated diaphragmatic valves  177  ( FIG. 7 ). One valve (DIV  6 ) controls the fluid flow from the filter vent connection to the system drain/vent line. One valve (DIV  10 ) controls the fluid flow from the gas removal reservoir recirculation line to the system drain/vent. One valve (DIV  4 ) controls the fluid flow from the filter output to the gas removal reservoir. One valve (DIV  11 ) controls the fluid flow from filter output line to the point of the external dispense digital valve. Those valves direct fluid flow during each operation with filter involved.  FIG. 7A  shows the assembled filter block. 
     Pneumatic Valves and Manifold  44   
     A bank of three-way pneumatic valves  44  ( FIGS. 3 and 11 ) is used to control the application of pressure or vacuum to the integrated valves used throughout the pump  20 . The preferred embodiment uses 8 SMC V 100  valves mounted on an SMC 8-position manifold. This manifold has 2 main flow paths that run the length of it. One path is for pressure and the other is for vacuum. These flow paths are capped at one end by 2 M5 cap screws, and have 2⅛″ tubing barb fittings screwed into the other end. The SMC valves are mounted on the front face of the manifold, which has the proper ports necessary to interface with these valves. On the top of the manifold are 8 SMC ⅛″ tubing fittings that run to each of the eight integrated valves used throughout the pump system  20 . Each SMC valve on the manifold has access to the common pressure and vacuum rails, but accesses only one of the eight ports out to the integrated valves. The pressure and vacuum lines to the manifold are connected from the panel connectors located on the pump enclosure  22 . The user need only need to connect fab pressure and vacuum source lines to the connectors on pump enclosure  22 .  FIG. 11A  depicts the connections of the various flare fittings. 
     Quick Disconnect Electronics: 
     The electronics are made to be easily replaced simply by loosening the enclosure attachments &amp; unplugging the connectors on the pump controller pigtails. ( FIG. 12 ). 
     Electronics Enclosure  23   
     The electronics enclosure  23  ( FIG. 2 ) is designed to house the main controller PCB  530  ( FIG. 13C ), network management PCB  50  ( FIG. 13C ), RDS translator PCB  539  ( FIG. 13C ), and optional digital valve controller PCB  538  ( FIG. 13C ). These boards are encapsulated by a two-piece sheet metal casing. The enclosure is designed to be mounted next to the pump enclosure and is easily removable from the mounting plate in the track without disturbing the pumping hardware. The enclosure allows for the connection of network cables, power cables, track communication cables, and an N 2  line. Cable connectors are external to the enclosure to allow easy removal of the electronics enclosure from the track. The enclosure is accented by stickers that display connection labels, model numbers, and brand logos. 
     Pump Enclosure 
     As shown most clearly in  FIG. 3 , the pump enclosure  22  comprises five stainless steel sheet metal pieces: a base plate  165 , a bottom enclosure  167 , a cover  173 , an access panel  169 , and a filter manifold bracket  248 . The purpose of the pump enclosure  22  is to house and protect the pump parts. The enclosure  22  features fluid connections for the source input, dispense output, and drain lines. The enclosure  22  also allows for the connection of the pump power and control wires as well as connections for N 2 , pressure, and vacuum lines. The pump enclosure is secured to a track mounting plate  243 , next to the electronics enclosure  23 . The filter manifold bracket  248  features mounting holes in a variety of different configurations to allow the user to mount multiple types of filter brackets (see Filter Manifold Bracket section below). There is a push button switch  25 A installed on the front of the enclosure to ensure the user is present when performing certain maintenance functions on the pump. The pump enclosure includes indicia (e.g., stickers) to identify the model number and to label the incoming and outgoing connections. 
     Track Mounting Plate  243   
     The stainless steel sheet metal track mounting plate  243  ( FIG. 3 ) allows the electronics enclosure  23  and the pump enclosure  22  to be installed side-by-side in the track. The track mounting plate  243  comprises a mounting-hole pattern for other pumps (e.g., Entegris RDS pump). The pattern of the mounting holes on the plate is symmetric so that the plate  243  can be installed upside down without changing the mounting orientation of the pump enclosure  22  and electronics enclosure  23 . The plate  243  allows the electronics enclosure  23  to be removed from the track without removing the pump  22  or vice versa. The symmetry of the enclosure mounting holes also allows the electronics enclosure  23  to be installed to either the right or the left of the pump enclosure, depending on the user&#39;s preference. There are PEM keyhole fasteners on one side of the track mounting plate  243  for securing screws that mount the enclosures to it. 
     Filter Manifold Bracket  248   
     The stainless steel sheet metal filter manifold bracket  248  ( FIG. 3 ) has predrilled mounting holes for attaching three different OEM filter manifolds. These preconfigured hole patterns allow for the attachment of either other components, such as, but not limited to, Entegris Impact 2, Entegris ST, or Pall EZD-3 filter manifold. 
     Bleed Port Syringe 
     During a drive system change, the user is prompted to remove the pumping fluid reservoir bleed screw BP 1  and attach a provided syringe ( FIG. 13 ). This syringe is used to push air into the pumping fluid reservoir  32  while valve  8  is open, thus pushing pumping fluid into the piston chamber  28 . The extra pumping fluid fills the piston chamber  28  to allow the insertion of a new motor drive assembly  24 . The provided syringe apparatus comprises, by way of example only, a 15 cc luer lock tip syringe, a luer lock to 1/16″ tubing coupling, and a tubing with  6 ″ in length and 1/16″ in ID. These pieces come assembled with the replacement pumping chamber diaphragm parts. As shown in  FIG. 13 , the syringe  222  comprises a 20 cc (by way of example only) Luer Lock tip, a tube coupling  263 , Luer Lock to 1/16 inch tube (by way of example only) and a tube  264  that is 1/16 inch by 4 inches long (again, only by way of example). 
     Remote Monitoring, Viewing and Controlling (RMVC) Subsystem 
     As discussed previously, the pump system  20  is software controlled in all aspects of the pump operation, including the dispense parameter monitoring, maintenance prediction and control, as well as the setup and control of normal pumping operations. The pump controller  38  ( FIG. 1 ) performs these functions through various interfaces not shown. The network management module  50  ( FIG. 1 ) allows Ethernet or wireless network control of the pump through the microcontroller  38 . In a simpler embodiment the pump controller  38  is directly connected to a specifically programmed graphical user interface (GUI) via a serial interface. The RMVC subsystem is also referred to by its tradename “Lynx”. 
       FIG. 13A  shows an embodiment of the pump of the present invention  20  having a graphical user interface (GUI) connected over a network, e.g., Ethernet, local area network (LAN), wide area network (WAN), a virtual private network (VPN), the “cloud,” the Internet or an Intranet. This is achieved via a web server WS that is connected to the pump controller  38  via the network management module NMM  50  to form a “web-served GUI.” In particular, the web-served GUI incorporates an Ethernet communication via an RJ45 connection. The web server WS is a small surface mount component on the NMM  50  housed in the pump  20  and is used for pump configuration, operation and monitoring using a standard web browser. All pump configuration parameters are entered and read using this interface. The web server WS communicates with the pump  20  on serial port 0 . The web server WS may comprise megabytes of flash memory suitable for web page storage. Hence, the web-served GUI is also referred to as the “remote monitoring, viewing and controlling (RMVC) subsystem. 
     As shown in  FIG. 13B , the web server WS may be enhanced with an additional Ethernet port for use with an optional networked device. Power-Over-Ethernet (POE) may be used to supply power to an optional networked device, e.g., a web cam. This Ethernet port is not used by the web server WS. The optional web cam may be used to observe the pump  20  operation remotely. It should be noted that the web cam is controlled by software supplied therewith.  FIG. 13C  depicts an exemplary web cam, such as the Wireless IP Network Camera Pan Tilt WIFI Webcam CCTV IR Night USA Plug 80413 by Yaloocharm. 
       FIG. 13D  depicts a block diagram of the web server interface that is enhanced with an additional, built-in, Wireless Ethernet port for use when the network cable would be inconvenient. 
       FIG. 13E  shows a block diagram of the NMM  50 . As mentioned previously, the NMM  50  includes the web server WS having a web server microcontroller  501  with embedded Ethernet engine, a CanBus driver (Controller Area Network bus)  502 , a 2 port Ethernet switch  503 , flash memory  504  and a Power over Ethernet (POE) power supply and controller  505 . An exemplary device for the web server microcontroller is the Freescale MCF52235CAL60 microcontroller. 
     Motherboard Interfaces 
     As shown in  FIG. 13F , the motherboard  530  of the pump controller  38  includes a central microcontroller, which is responsible for all of the system control functions. The microcontroller is connected to the pump stepper motor through the stepper motor drive  532 . The microcontroller is connected to the valve drivers  533  and pressure sensor/PCB electronics  48  via a serial connection. In the embodiment depicted, the pressure sensor electronics include a separate microcontroller which monitors pressure and sends this data to the central pump controller  38 . As stated above, the central microcontroller is also connected to the NMM  50 , which allows GUI control of the pump process through the Internet either via Ethernet or WiFi wireless connection. The pump controller  38  is also optionally connected to a digital valve controller  536  for control of up to three valves. The pump controller  38  is also optionally connected to the RDS translator module  539 , an external RS232/485 converter  537  and a track I/O daughter card  538 . 
     GUI Options 
     A first GUI option is a standard singe platform installed GUI, block diagrams of which are shown in  FIGS. 13G-13I . The standard GUI may be modified for use with the tiny web server WS. This GUI is still a single platform and the GUI requires installation on the client machine. 
     A second more preferred GUI is the cross platform JAVA virtual machine GUI, block diagrams of which are shown in  FIGS. 13J-13L . In particular, as compared to the first GUI option, the second GUI option is a more flexible GUI when written as a JAVA applet. This applet may be served from the tiny web server WS and utilizes the JVM (JAVA virtual machine) runtime libraries. These runtime libraries are part of the JVM. JVM supported platforms, as shown in  FIG. 13L , that can serve as potential GUIs are: Windows® (x86-64, IA-64 processors), Solaris® (x86-64, SPARC processors), Linux (x86, x86-64, IA-64, PowerPC, System z (formerly Z-Series) processors), HP-UX (PA-RISC, IA-64 processors); i5/OS and AIX (both PowerPC® processors). 
     An exemplary operational description is as follows:
         1) Open a web browser and input the pump&#39;s Internet Protocol (IP) address;   2) The GUI, written as a JAVA applet is served to the web browser from the tiny web server WS;   3) The JAVA applet is executed in the web browser&#39;s JVM;   4) The GUI, as written, appears in the web browser;   5) Data fields may be read and/or changed and these updates are sent to the tiny web server WS over Ethernet via UDP; the tiny web server WS converts the UDP (user datagram protocol) commands to the Assignee&#39;s ASCII serial protocol equivalent and updates the pump. Using UDP allows an unlimited number of “listeners on the data connection.” This is useful for multiple people observing and for automatic data logging devices such as the Assignee&#39;s “Failsafe” product.       

     As to the GUI&#39;s internal firmware, this may be updated in four ways:
         1) via a flash update plug: this method requires physical access to the pump electronics in addition to a laptop with a BDM (background debug mode) flasher;   2) via a full web update: this process may be used when there is a network connectivity to the Assignee&#39;s update servers. This option does not require physical access to the pump electronics; and   3) via a request update: the user in the RMVC interface simply clicks on the “Program update” option the program firmware is downloaded and programmed from the Assignee servers; and   4) Via an automatic setting: If the user had previously selected “Automatic Program Updates”, then the RMVC system downloads and programs the firmware whenever an update is available.       

     It should be noted that an internal network update is also available. In particular, this option may be used when there is no network connectivity to the Assignee update servers. This option does not require physical access to the pump electronics. This option is similar to “Full Web update” described above except an update folder is specified on the internal network instead of the Assignee&#39;s update server. 
     The RMVC subsystem adds additional value by being able to provide a direct camera and audio connection between a technician working with our pump and our field service workers. As mentioned previously, an exemplary camera and audio device is the Wireless IP Network Camera Pan Tilt WIFI Webcam CCTV IR Night USA Plug 80413 by Yaloocharm (as shown in  FIG. 13C ). 
     a. Video Camera for use in yellow light (semi FAB) environment 
     b. Yellow camera light for use with a video camera in a yellow light (semi FAB) environment. 
     c. Wide range pan, tilt, zoom, lights, focus, audio, for unattended remote control operation. 
     To operate this feature, the FAB tech clicks “Request Service” Button in NMM GUI. This sends a Service request to the IDI remote service center. IDI Field service personnel acknowledge the request &amp; initiate a remote connection with “service” credentials. At this time the IDI remote service center personnel have full, remote control, of all of the video camera, &amp; pump controls. Audio may be enabled to discuss the issue with the FAB tech. FAB safe video camera lights may be activated &amp; the camera&#39;s pan, tilt, and zoom can be manipulated to observe any pump malfunction. The IDI service personnel may operate the pump while observing its operation. With the proper credentials, anyone can join the audio/video feed &amp; manipulate the pump or just observe &amp; listen while the diagnosis &amp; repairs are being made. 
     It should be understood that the RMVC subsystem can be used an unlimited number of pump devices and that its integration with the pump system of the present invention  20  is by way of example only. The RMVC subsystem can be used, by way of example only, for any process equipment used in a wafer fabrication facility, or in medical facilities, or in oil and gas facilities, or in food processing facilities and even in cosmetic facilities. 
     Chambers as Compared to Reservoirs 
     As mentioned previously, the two reservoirs associated with the pump system  20  are the gas removal reservoir  30  and the pumping fluid reservoir  32  ( FIG. 1 ). These are referred to as reservoirs since they have a set volume capacity. The three chambers on the pump system  20  are the process fluid chamber  34 B, the pumping fluid chamber  34 A, and the piston chamber  28  ( FIG. 1 ). These are referred to as chambers because their volume can change. The pumping fluid chamber and process fluid chamber volumes can change as the diaphragm  36  moves around inside the pumping chamber  34 . The pumping chamber  34  is the chamber where the pumping chamber diaphragm  36  is mounted. The overall combined volume of the two chambers, the pumping fluid chamber  34 A and the process fluid chamber  34 B, remains constant, but because of the flexible PTFE diaphragm component  36 , the individual chamber volumes may change. The piston chamber  28  has a dynamic volume since the piston moves around and affects a change of volume. 
     Pump Chambers: Piston Chamber, Pumping Fluid Chamber, and Pumping Fluid Reservoir 
     The pumping fluid in the single head pump system  20  is primarily contained in two chambers (i.e., piston chamber  28  and pumping chamber  34 A) and one reservoir  32  associated with the pump body  22 . The first of the three pumping fluid chambers houses the piston  26  and the piston bore  28 . In the pump system, mechanical energy is converted from the stepper motor  24 E that assists the piston  26  in creating a reciprocating motion in piston chamber  28 . The second chamber is the primary pumping fluid chamber  34 A that is responsible for transferring the work done by the piston  26  through the pumping fluid to the diaphragm  36 , which expands or contracts with the motion of the piston  26 . The pumping fluid reservoir  32  stores the pumping fluid that is unused during normal dispense actions, as well as assists in the prevention of air bubbles from entering into the other pumping fluid chambers. The remainder of the pumping fluid resides in the fluid paths connecting the two chambers/one reservoir as well as the valves located along these fluid paths. The integrated pneumatically operated diaphragmatic valves  5  and  8  control the fluid flow from the piston chamber to the other two chambers (see isolation valves  5  and  8 ). 
     How the Process Fluid Chamber Changes Volume to Pump Fluid: 
     The present invention pump system  20  uses the incompressible pumping fluid as a medium to transmit the motion of the piston  26  to a rigid chamber  34  ( FIGS. 1 and 1A ) split with an internal Polytetrafluoroethylene (PTFE) diaphragm  36 . The rigid nature of this chamber coupled with the flexibility of the diaphragm  36  causes the portion of the chamber in the pump head (see pump head section) to increase and decrease in process fluid volume proportionally with the pumping fluid volume. The pump head portion of the chamber  34 B is filled with process fluid that the user intends to dispense. Since the process fluid is incompressible, fluid flow is affected as the available chamber volume changes. 
     Pump Head  22 B 
     How the Pump  22  Actually Pumps the Fluid: 
     The pump  22  can dispense a variety of chemical fluids. The fluid being dispensed, as mentioned previously, is referred to as the process fluid and the flow of this process fluid is controlled by the pneumatically operated diaphragmatic integrated valves ( 1 ,  2 ,  3  and  7 ). These DIVs are located on both process fluid paths connected to the process fluid chamber  34 B. Process fluid dispenses are caused by closing DIV  1  and DIV  2  and opening DIV  3  in the line while the pumping fluid flows into the pumping fluid chamber  34 A. The pump  22  finishes its dispense procedure by “recharging” the gas removal reservoir  30  from which it made the dispense by closing DIV  3  and opening DIV  1  and DIV  2  while the pumping fluid flows out of the pumping fluid chamber  34 A. This process is repeated to cause a controlled fluid flow. The head portion  34 B of the process fluid chamber has a total of two fluid paths connecting it with an external valve block  40  and the associated gas removal reservoir  30 . All fluid paths from the head portion of the process fluid chamber are controlled through the DIV valves. 
     Gas Removal Reservoir  30 : 
     As mentioned previously, the pump system  20  includes the gas removal reservoir  30 . This reservoir  30  is used to prevent air from entering the process fluid chamber  34 B of the pump head  22 B. The addition of air in the process fluid chamber  34 B would induce a delay in fluid flow. Since air is a compressible gas, the air expands and compresses absorbing some of the volumetric changes in the pump head process fluid chamber  34 B and prevents the fluid flow from equaling the volumetric change. The fluid path between the associated gas removal reservoir  30  and the process fluid chamber  34 B connects the bottom sections of both chambers. 
     How the Head  22 B Keeps Air Out of the Process Fluid Chamber: 
     The process fluid pools at the bottom of the gas removal reservoir  30  (also referred to as the “pre reservoir”) while any air will float to the upper section of the reservoir  30 , preventing the inclusion of air in the process fluid chamber. The upper section of the gas removal reservoir  30  is shaped so as to concentrate the rising bubbles to a single point (see  FIGS. 1A and 6-6B ). The removal of the air bubbles is aided by a process that expels, or purges, a small amount of liquid into the fluid path connected with the uppermost portion of the gas removal reservoir. This fluid path leads to a drain line and is closed during all normal operations of the pump system. 
     External “Out” Paths: 
     The gas removal reservoir  30  has a total of four fluid paths ( FIG. 1 ) connecting it with the process fluid chamber  34 B, the drain line, the fluid source FR connection of the pump system  20 , and an external valve block  40 . The connections to the process fluid chamber drain line and fluid source are routed through the pneumatically operated diaphragmatic valves to control flow. Fluid flow through the fluid inlet from the external valve block is controlled by a valve located in the external block. This means that a separate valve inside to the pump head is not needed. 
     Gas Removal Reservoir&#39;s  30  Shape: 
     The reservoir&#39;s cross sectional area is shaped as a quadrilateral (see  FIGS. 6-6B ) with the bottom face oriented along a horizontal plane, the two parallel sides oriented along a vertical plane and an angled upper face. The intersections of all the faces of the reservoir incorporate a radius to prevent atmospheric bubbles from collecting in the corners. The intersection points of the three fluid paths on the upper face are intended to aid the evacuation of atmospheric bubbles. In order from closest to furthest from the horizontal bottom face are the fluid source connection, the fluid inlet from the external block, and finally the drain line connection. The source inlet is the lowest to ensure bubbles cannot travel into this connection while the fluid in this path is not moving. The fluid inlet from the external valve block is the next lowest connection. During the startup procedure the fluid traveling through this path will fill the line and carry any atmospheric bubbles out of the path. The highest connection is the drain line. The angled face of the reservoir ensures any air displaced during the startup and purging procedure will collect directly beneath the drain connection. 
     Valve Sequencing for Operation-Microcontroller  38  Operation 
     Dispense: 
     The dispense ( FIG. 18 ) starts from the pre-charge position and begins when the pump  22  receives a trigger signal. The DIVs  3 ,  5 ,  11  and the external dispense valve  9  (e.g., the IDI Digital Valve) are opened and the motor  24 E moves the piston  26  down to the user specified volume. This position is designated as End of Dispense (EOD). When EOD is reached, the valves are closed and the pump  22  begins the automatic procedure to fill itself by completing the “Recharge” operation. 
     Recharge: 
     The recharge ( FIG. 18 ) starts by opening the valve  1  separating process fluid from the source inlet and gas removal reservoir inlet, the valve  2  separating process fluid the chamber and the gas removal reservoir, and the valve  5  separating pumping fluid from the piston chamber  26  and the pumping fluid chamber  34 A. Driven by the motor  24 E, the piston  26  moves back to the home reference position (HRP) which creates a negative pressure in the process fluid chamber  34 B and “recharges” or fills process fluid from the gas removal reservoir  30 . At the same time, the gas removal reservoir  30  is fed process fluid through valve  1  that is supplied by the fabrication reservoir FR. All other valves remain closed when the recharge takes place. When the recharge operation is complete all valves are closed. 
     Precharge: 
     The pre-charge ( FIG. 19 ) begins after any operation that lets the pump  22  return to a “ready”, PSO status such as after a Recharge or after exiting “Maintenance Mode”. The pre-charge opens valves  2  and  7  and moves the piston forward  26  (down) to push a predetermined amount (e.g., 3 mL) of pumping fluid through the vent line. This action allows the high pressure developed due to valve closures to be pushed out through the source line to lower the pressure and then closes valves  2  and  7 . The piston  26  moves forward to begin building up pressure to a user defined pressure (e.g., +1.0 psi). This is done by moving the stepper motor  24 E in proportion to the pressure error from actual pressure to desired pressure. Once the user-defined pressure is reached, the pump  22  returns a ready status and is in a loop checking for pressure fluctuations. If the pump  22  raises or lowers to +/−15% of the desired pressure, the pump  22  corrects the pressure by moving the piston  26  forwards or backwards to achieve the specified pressure. This action allows the pump to always start the dispense from the same pressure point providing extremely consistent dispense performance. 
     Purge to Vent (Prime Gas Removal Reservoir  30 ): 
     Purge to Vent ( FIG. 20 ) is an operation that pulls fluid from the source reservoir into the pump  22  and purges the air out of the gas removal reservoir  30  and the source line tube. This operation must be completed while the pump is in “Maintenance Mode”, and is accomplished by activating the “Purge to Vent” command from the “Maintenance” window, in the Purge tab of the GUI (of the remote monitoring/control subsystem) or by clicking on the “purge to vent” button in the “Purge” operation drop down list under the “Maintenance” tab of the RMVC subsystem. This command is a manual input that can be specified to run infinitely or to run a specified number of cycles. A cycle includes one purge to the vent line and one recharge. The pump  22  begins this procedure by checking if the piston is at HRP. If the piston  26  is at HRP, then it begins the purge to vent process. If the piston  26  is not at HRP, then the pump  22  recharges until the piston  26  reaches the HRP. This recharge is identical to the standard Recharge procedure discussed previously. Once the piston  26  is at the HRP, the pump  22 , with valve  5  open, opens valves  2  and  7  and moves the piston  26  down to the 11 mL mark. The pump  22  then closes valves  2  and  7  and performs a Recharge by opening valves  1  and  2  and moving the piston  26  back to HRP. The pump  22  repeats this process until the designated number of cycles has been completed or until the user stops the operation. Once this operation is done, when complete the pump is ready for the user to exit “Maintenance Mode” which begins the Pre-charge operation. 
     Priming the gas removal reservoir  30  first from the source gives the pump  22  enough fluid to start recirculation using only the liquid in the gas removal reservoir  30 . This allows the pump  20  to run multiple cycles of the recirculation to gather as many bubbles in the reservoir as possible without wasting any fluid of out the vent line. 
     Purge to Output (Prime Process Fluid Chamber  34 B): 
     Purge to Output ( FIG. 21 ) is an operation that pulls fluid from the source reservoir into the pump  22  and purges the air out of the source line tube and the process fluid chamber  34 B. This operation must be completed while the pump  22  is in “Maintenance Mode” and is achieved by activating the “Purge to Output” command from the “Maintenance” window, in the Purge tab of the GUI of the RMVC subsystem or by clicking on the “purge to output” button in the “Purge” operation drop down list under the “Maintenance” tab in the RMVC subsystem. This command is a manual input that can be specified to run infinitely or to run a specified number of cycles. A cycle includes one purge to the output or dispenses line and one recharge. The pump  22  begins this procedure by checking if the piston  26  is at HRP. If the piston is at HRP, then it begins the purge to output process. If the piston  26  is not at HRP, then the pump  20  recharges until the piston  26  reaches the home position. This recharge is identical to the standard Recharge procedure from above. Once the piston  26  is at HRP, the pump  26 , with valve  5  open, opens valve  3  and moves the piston  26  down to the 11 mL mark. The pump then closes valve  3  and performs a Recharge by opening valves  1  and  2  and moving the piston  26  back to HRP. The pump  22  repeats this process until the designated number of cycles has been completed or until the user stops the operation. When complete, the pump  22  is ready for the user to exit “Maintenance Mode” which begins the Pre-charge operation. 
     Initial Priming without BIB Pump Initially Primed 
     PPRM 2  (Prime Filter Housing;  FIG. 22 ): 
     The present invention pump system  20  incorporates a filter attachment which helps to reduce trapped air bubbles in the process fluid line. The filter housing is primed by the following procedures. Step 1: A maximum dispense volume proceeds with piston  26  moving from home position to the furthest position in piston chamber  28 ; the valve  3  controlling process fluid flow from pumping fluid chamber  34 A to filter inlet, the valve  6  controlling the process fluid flow from the filter vent to the external drain line, and the valve  5  separating pumping fluid between the piston chamber  28  and process fluid chamber  34 B are open; all other valves including the external digital valve  9  at the dispense line remain closed. This allows process fluid only to pass through the filter housing and exit from the filter vent line. Step 2: The following recharge from the source line takes place with valves  1 ,  2 , and  5  open and valves  3 ,  4 ,  6 ,  7  and  8  remain closed. The external digital valve  9  can be at any state, open or closed. The recharge is at maximum recharge volume with a full stroke motion of the piston chamber  28 . The action of step 1 and 2 are repeated until process fluid comes out of the filter vent line without air bubbles. 
     PPRM 3  (Prime Filter Substrate;  FIGS. 23A-23B ): 
     The filter substrate  42  has to be wetted for proper operation of the filter and to remove all of the air from the filter can be primed via the following “prime filter substrate” function. The filter substrate  42  can be primed by the following steps. Step 1: Valves  3 ,  4 ,  5 , and  7  are open; valves  1 ,  2 ,  6 , and the external digital valve  9  remain closed. That allows process fluid to enter into the filter  42  from the process fluid chamber  34 B and to emerge from the filter  42  via the filter output port and into the pump filter recirculation line. The process fluid in the recirculation line then enters into the gas removal reservoir  30  and continues through the gas removal reservoir vent/drain line. During this priming process, the maximum dispense volume is used, 11 mL, as the piston moves from the HRP to the 11 mL end of dispense (EOD). The pump then “recharges from source” by opening DIV  1 ,  2 ,  5  and closing DIV  3 ,  4 ,  6 ,  7 ,  8 , and  9  and retracting the piston from EOD to HRP. Step 1 is repeated one more time, for a total of two times. The next operation of the PPRM 3  functions executes is step 2. Step 2 starts by opening DIV  3 ,  4 ,  5 , and  7  ( FIG. 11A ) and closing DIV  1 ,  2 ,  6 ,  8  and valve  9  and pushes 11 mL of process fluid into the filter  42  from the process fluid chamber  34 B. The process fluid then exits the filter out of the filter output port and continues into the recirculation line, which leads back to the gas removal reservoir  30  while air is pushed out of the process fluid vent/drain. The pump then “recharges from gas removal reservoir  30 ” by opening DIV  2 ,  5  and  7  and closing valves  1 ,  3 ,  4 ,  6 ,  8  and  9  and retracting the piston from EOD to HRP. Step 2 is repeated three times, which recirculates the fluid and helps accumulated air from the filter in the gas removal reservoir  30 . The gas removal reservoir  30  expels the air out of the gas removal reservoir vent/drain in all three steps. 
     The whole filter has been primed when all of the bubbles have been collected at the top of the gas removal reservoir  30  and the filter output line is void of air. The pump will run a few more recirculation cycles that recharge from the source in order to push new liquid into the gas removal reservoir  30  and vent the air bubbles. Step 3 repeats step 1 four times. This step is programmed to be repeated at least four times to ensure process fluid comes out the filter output line without the presence of air bubbles. If the filter has air bubbles present, the user can input the command until no air is seen exiting the filter output line. 
     Startup Operations 
     A description of the startup process of the pump system  22  is as follows: 
     Initial Pump Filling and Priming 
     The pump system  22  arrives on location containing only the pumping fluid housed in the pump body  22 A. The initial filling and priming process helps to fill the flow path of user&#39;s desired processing fluid. This process requires a pre-existing fluid source with a pressurized BIB at the inlet of the pump  22 , a Fab reservoir FR with a Fab reservoir vent/drain valve  14 , and an optional external dispense valve (external digital valve  9 ) to provide more customizable dispense control at the outlet of the pump. Upon pump installation, the user connects the fluid lines to the pump system  20 . This includes the line from the process fluid source FR to the pump inlet, the fluid outlet lines to the point of external dispense valve, and the external track drain line from the pump system filter vent and gas removal reservoir drain. The pressurized nitrogen (or dry air) line and the vacuum line need to be connected to pump system  20  for valve controlling. 
     The initial filling and priming is followed by completion of pump auto-balance. The initial filling and priming process begins with the user starting the software process for this operation. There are two scenarios in the customers&#39; location: 
     Scenario 1: The first scenario is that the BIB is pressurized. A track reservoir (i.e., Fab reservoir FR) may be in place between the initial source and the pump system  20 . If so, the pump controller  38  first closes the Fab reservoir vent/drain valve  14  and valve  1  located in the flow path between the initial source and the pump inlet; fluid is then pushed into the Fab reservoir FR by the pressurized BIB. Once the source is pressurized, the pump controller  38  opens the following valves: the valve  1  isolating the internal gas removal reservoir from the source inlet, the valve  2  isolating the gas removal reservoir  30  to the process fluid chamber  34 B, the valve  3  isolating the process fluid chamber  34 B from the external valve block flow path connected with the filter fluid inlet, the valve  5  separating pumping fluid from the piston chamber  28  and process fluid chamber  34 A, and the external point of the dispense valve. 
     The following valves are closed to direct the fluid through the desired path: the Fab reservoir drain/vent valve V FAB , the valve  7  isolating the gas removal reservoir  30  from the drain line, the valve  6  controlling the flow from the filter vent to the external drain line, and the valves  4 ,  6  and  10  controlling fluid flow from the filter outlet back to the gas removal reservoir  30 . The user controls the closing of the open valves to accommodate the varying time required to fill the pump system  20  and attached tubing. The varying time required to complete this process is a result of the varying internal total volume of the tubing connecting the pump system  20  with the initial fluid source FR and point of dispense as well as the varying flow rates. These rates are functions of such fluid characteristics such as density, viscosity, and temperature. Other factors with limited effect would be the density of the surrounding air and the flow rate of the external point of the dispense valve. Once the process fluid travels to the point of dispense, the majority of the volume in the pump system  20  has been filled with the process fluid. 
     Then, valves  3 ,  4 , and  5  are opened to dispense into the gas removal reservoir  30  while all other valves stay closed. The maximum recharge from the source line is the following action by opening valves  1 ,  2  and  5 . This serial action ends when the automated pressure feedback in the pumping fluid reservoir  32  meets the pressure criteria in the gas removal reservoir  30 . Then the filter change routine and recirculation operation are required. 
     If the Fab reservoir FR is not in the track, the pump system housing can be directly filled by the same procedures without filling the Fab reservoir FR first. 
     Scenario 2: The second scenario is that the BIB is not pressurized and a Fab reservoir FR is in place between the initial source and the present invention pump system  20 . The pump system  20  and Fab reservoir FR need to be filled by pump system  20  itself. It starts from a maximum dispense to the point of the external digital valve by only opening valves  3  and  5 , and the external digital valve  9 . Then it is followed by a maximum recharge from the source line by only opening valves  1 ,  2  and  5 . This serial action ends when the Fab reservoir FR is filled and process fluid comes out of the dispense tip. 
     Afterwards, valves  3 ,  4  and  5  are opened to dispense into the gas removal reservoir  30  while all other valves stay closed. The recharge from the source line will be the following action by opening valves  1 ,  2  and  5 . This serial action ends when the automated pressure feedback in the pumping fluid reservoir  32  meets pressure criteria in the gas removal reservoir  30 . Then the filter change routine and recirculation operation are required. 
     If the Fab reservoir FR is not in track, the pump system housing can be directly filled by the same procedures without filling the Fab reservoir FR first. 
     Maintenance Operations 
     A description of the maintenance operations of the pump system  20  is as follows: 
     Fluid Recirculation and Purging 
     The pump system  20  incorporates a fluid recirculation function to reduce the process fluid waste during the process of purging any air from the interior of the pump  22 . This function allows the user to reduce the total cost of ownership for the pump system  20  through reducing the fluid consumption during purging as well as allowing the pump system  20  to periodically internally recirculate the fluid. The ability to periodically recirculate the process fluid reduces the possibility fluid could become static in the tubing, preventing the fluid from congealing or drying and thus causing stoppages. 
     The internal fluid recirculation in the pump system  20  begins with the piston  26  at the HRP. The pump controller  38  opens the valve  3  controlling flow from the process fluid chamber  34 B to the filter inlet, the valve  4  controlling the flow from the filter return outlet to the gas removal reservoir, and the valve  7  controlling flow from the gas removal reservoir to the drain line. This valve must be open to allow the recirculated fluid to fill the reservoir  30  and displace any air or other gases out of the drain line. All other valves must remain closed. The pump controller  38  performs a maximum volume dispense, closes the open valves, and opens the valve  2  controlling flow from the gas removal reservoir  30  to the process fluid chamber  34 B and the valve  7  controlling flow from the gas removal reservoir  30  to the drain line. During the entire recirculation process the point of dispense valve must remain closed. 
     During the recirculation process the internal fluid flow traps any atmospheric bubbles in the gas removal reservoir  30  or the filter  42  near the drain connections. The pump  22  displaces process fluid into the gas removal reservoir  30 , and the collected bubbles of air or other gases along with a small amount of process fluid will be forced into the drain line. This process will occur twice, once to purge the filter vent and again to purge the gas removal reservoir  30 . During the filter purging process, with the piston  26  at the HRP, the valve  3  controlling flow from the process fluid chamber  34 B to the filter inlet, and the valve  6  controlling flow from the filter to the drain line open while all other valves remain closed. The two open valves will close, and the valve  1  from the process fluid source FR to the gas removal reservoir  30  and the valve  2  between this reservoir  20  and the process fluid chamber  34 B will open to allow the piston  26  to recharge from source. During the gas removal reservoir purging process, the valve  2  controlling flow from the process fluid chamber  34 B to the gas removal reservoir  30  and the valve  7  controlling the flow from the gas removal reservoir  30  to the drain line will open. All other valves will remain closed. The two open valves will close and the piston  26  will recharge from the source. 
     Electronics Enclosure  23  Removal 
     To assist with in track repairs, the pump  22  also allows for electronics replacement with ease. The electronics enclosure is completely self-contained and can be easily removed by simply disconnecting the cables and pulling the box out. 
     To remove the electronics enclosure, the user needs to disconnect five external connections. Two RJ45 connectors, one serial connector, one power connector and then, once these operations have been completed, the user can then disconnect the DB44 connector to disconnect the electronics enclosure  23  from the pump body  22 A itself. The enclosure  23  can now be slid upward and out to disconnect the box from the mount and can be taken out of the cabinet. A new electronics enclosure  23  can now be installed by reversing the removal procedure. 
     Pump Head in Track Removal/Repair/Replacement 
     To remove the pump head  22 A for in track maintenance purposes, the pump head housings, including the process fluid chamber  34 B and gas removal reservoir  30 , need to be emptied by running the “System Drain” function. This operation allows the user to nearly empty the process fluid in the process fluid chamber and gas removal reservoir. Hence, the pump head  22 A can then be removed by unscrewing six screws on the back plate. When removing the pump head  22 B the user needs to be careful to keep the PTFE head (white) and the back plate (stainless steel) pressed together and removed as one unit. The screws are also to be kept together as one with the pump head  22 B. The pump head  22 B with six screws can be slowly taken off from the pump body  22 A, and the pump head block  78  should be held tightly while it is taken off with a backwards tilted angle; the user needs to be prepared for a small amount of process fluid residuals in the process fluid chamber  34 B and gas removal reservoir  30  to leak out. 
     Users can change all the components on the pump head  22 B ( FIG. 6 ), including the pump head block  78 , pump head O-ring  207 , flare fitting  47 , flare fitting cap  350 , set screws  111 , head diaphragm  84 , pump head pneumatic plate  80 , pneumatic quick disconnect  95 , screws  99 , gas removal reservoir O-ring  281 , valve O-rings  117 , mounting foot  261 , and elbow fitting  93 . All the tubing connected to the gas removal reservoir  30  can also to be replaced/changed. The user can change one item or multiple items when the pump head  22 B is taken off, or the complete pump head  22 B can be replaced. An auto-balance cycle must be run after the pump head  22 B is reinstalled since the pressure in the pump system  20  will be affected by the change. 
     Pumping Fluid Chamber Diaphragm Replacement 
     Users would replace the pumping fluid chamber diaphragm  36  when it is extremely deformed or out of shape. To perform this action, the pump head  22 B needs to be emptied using the “System Drain” function. The pump head  22 B needs to be removed as described in the “pump head in track removal/repair/replacement” section. Then the pump  22  needs to be put in the special maintenance mode as described in the “in track drive assembly change” section that allows pumping fluid only to be able to transfer between the piston chamber and pumping fluid reservoir  32  to isolate the pumping fluid chamber  34 A. The user needs to take off the bleed screw from the bleed screw port BP 2  to the pumping fluid chamber  32 . Then using the provided syringe ( FIG. 13 ) with thin tubing attached, draw the pumping fluid out of the pumping fluid chamber  34 A until a very small amount of pumping fluid is left at the bottom of the pumping fluid chamber  34 A to block the flow path. The user can save the pumping fluid in a container and reuse it after placing the new diaphragm. The pumping fluid chamber diaphragm hold down plate  64  ( FIG. 4 ) can be removed by unscrewing all the screws  66 . When removing the hold down plate  64  and diaphragm  36 , the user needs to tilt the pump body  22 A in order to keep residual pumping fluid at the bottom of pumping fluid chamber  34 A and reduce leaking. The user needs to be aware of the residual pumping fluid around the diaphragm and be prepared for a small amount of leaking. 
     This allows the user to change/replace the following parts (see  FIG. 4 ): bleed screw  52 E on the pumping fluid chamber  34 A, pumping fluid chamber O-ring  211 , pumping fluid chamber diaphragm  36 , pumping fluid chamber diaphragm hold down plate  64 , and screws  66 . After the new pre-stretched diaphragm with hold down plate and screws are reinstalled, the user needs to fill up the process fluid chamber  34 B with the provided syringe ( FIG. 13 ) and reuse the pumping fluid from the pumping fluid chamber  34 A. Slowly inject pumping fluid to the pumping fluid chamber  34 A through bleed port BP 2  ( FIG. 4 ) until the pumping fluid appears to overflow from bleed port BP 2 . The bleed screw  52 E needs to be installed back on the process fluid chamber  34 B. After the pump head back is reinstalled onto the pump body  22 A, the special maintenance function needs to be disabled as described in “in track drive assembly change” with closing valve  8  and opening valve  5 . That allows the pump system  20  back to regular maintenance mode. The pump system  20  is required to run an auto-balance after a pumping fluid chamber diaphragm  36  replacement and after a process fluid chamber diaphragm  84  replacement. 
     Pressure Sensor Calibration: 
     The purpose of pressure sensor PS calibration is to set a default “zero” pressure when the pump internal pressure is equalized to atmospheric pressure. The pressure sensor PS needs to be calibrated when pumping fluid reservoir bleed port BP 1  is uncapped and all valves in fluid path are open. Place the unit in maintenance mode. All valves can be opened by typing “VON1, 0” in command input line in the GUI. Then the pressure sensor default can be set through the GUI recipe page. Thus, the user can set default “zero” pressure through “set pressure to zero” feature in the GUI. This operation is essential since many operating locations will have different atmospheric pressures than the manufacturing location and this allows for the pump  20  to be calibrated for that particular locations ambient atmospheric pressure. 
     Recirculation: 
     The Recirculation feature (see  FIGS. 16A-16B ) of this pump  20  is a feature that helps reduce the air in the tubes that forms from various places (such as in the filter) and allows for a small circulation system to permit fluid movement while the dispense portion of the pump is idle. This feature may be turned on or off as designated by the user. The Recirculation feature is activated or deactivated while the pump is in “Maintenance Mode” and is completed by selecting the “enable” or “disable” command from the “Maintenance” window, Recirculation tab of the GUI or by the RMVC subsystem. When the recirculation feature is deactivated, the valve  4  for the recirculation line is closed (on the Filter Block  40 ) and process fluid moving out of the process fluid chamber  34 B and into the filter  42  simply continues on its path in the dispense tube. If the Recirculation feature is activated however, the pump  20  opens valve  4  during a dispense and keeps the external valve closed. This operation opens valves  3 ,  4 ,  5 , and  7  to allow for dispensed process fluid to move into the gas removal reservoir  30 . With valve  4  open, there is a back pressure due to the incompressibility of the fluid which does not allow the fluid to continue in the dispense tip path and the fluid is then forced into the recirculation line. The fluid dispensed during recirculation is “dispensed” into the gas removal reservoir and displaces the air pocket that is kept in the gas removal reservoir. Valve  7  is opened as well to allow for the displacement of air as the process fluid is forced into the gas removal reservoir  30 . The pump  22  “recharges” from the gas removal reservoir  30  by opening valves  2 ,  5 , and  7  filling the process fluid chamber  34 B with the same volume of liquid that was pushed into the gas removal reservoir. 
     Drain Function: 
     The system  20  has a drain feature ( FIGS. 24A and 24B ) that is used in the draining of the pump of process fluid to allow for certain maintenance functions to occur. Once a SYSTEM DRAIN has been performed, the filter must be discarded. This operation removes most of the fluid that is stored in the gas removal reservoir  30 , the process fluid chamber  34 B and the recirculation line, but there will be some residual fluid in the pump  22 . The filter  42  will still hold some of its volume amount of fluid. The System Drain function is activated or deactivated while the pump is in “Maintenance Mode” and is completed by entering the command SDRN 1  to enable or SDRN 1  to disable. Before the SYSTEM DRAIN can be completed, the user must disconnect and cap off the source line from the pump to allow for the introduction of air into the pump system. This function begins the pump is a user-operated loop that drains the pump of process fluid. This operation begins with a purge to output operation to the full 11 mL by opening valves  3  and  5 , external dispense valve such as the LP Digital Valve  9 . Once the pump  22  has completed this dispense it closes valves  3  and  5  and the external valve. The pump then “recharges” from the gas removal reservoir  30  by opening valves  1 ,  2  and  5  and pulling in 11 mL of air. The pump continues with the system drain operation by closing valves  1 ,  2  and  5  and opening valves  3 ,  4 ,  5  and  7  to push fluid out of the recirculation line into the gas removal reservoir. The pump then closes valves  3 ,  4 ,  5  and  7  and opens valves  2 ,  5  and  7  and pushes fluid out of the gas removal reservoir drain line and then closes valves  2 ,  5  and  7 . This series of operations is repeated until the user disables the System Drain function. This function removes process fluid from the pump  22  allowing for the removal of the pump head  22 B. 
     System Drain Operation 
     1. Remove and cap FAB source line 
     2. Purge to output
         a. Opens  3 , 5 ,DV   b. Valves  1 , 2 , 4 , 6 , 7 , 8  closed (DV at any state)   c. Recharge from source
           i. Opens  1 , 2 , 5     ii. Valves  3 , 4 , 6 , 7 , 8  closed (DV at any state)   
               

     3. Recirculation
         a. Opens  3 , 4 , 5 , 7     b. Valves  1 , 2 , 6 , 8 , DV closed   c. Recharge from gas removal reservoir
           i. Opens  2 , 5 , 7     ii. Valves  1 , 3 , 4 , 6 , 8  closed (DV at any state)   
               

     4. Purge to vent
         a. Opens  2 , 5 , 7     b. Valves  1 , 3 , 4 , 6 , 8  closed (DV at any state)   c. Recharge source
           i. Opens  1 , 2 , 5     ii. Valves  3 , 4 , 6 , 7 , 8  closed (DV at any state)   
               

     5. Repeat steps 2-4 (until the user sees that no fluid comes out of the dispense tip or the gas removal reservoir drain line) 
     Ship Function 
     This ship function is a feature programmed into the pump  20  which is used to remove all air from all of the pumping fluid chambers and reservoirs. This function is to be used during assembly and operates by pushing all of the pumping fluid from the piston chamber  28  to the pumping fluid reservoir  32 . This operation is completed by the user removing the bleed screw BP 1  on the pumping fluid reservoir  32  and inputting the command “SHIP1”. This command opens valve  8  and advances the piston downward to the 11 mL end of dispense (EOD) mark. This moves the piston  26  to the bottom of the piston chamber  28  while pushing the pumping fluid to the pumping fluid reservoir  32  and pushing the air in the pumping fluid reservoir  32  out of the pump. The user will see a little bit of pumping fluid emerge from the pumping fluid reservoir  32 . The user then caps the bleed port BP 1  on the pumping fluid reservoir with the bleed screw and the pump body now is void of air and is ready for shipping. 
     Out of Box Operation ( FIGS. 25A and 25B ): 
     The pump  22  arrives on location to the user with the pump body completely filled with pumping fluid and void of any air. The user then installs the pump  22  into the track system and remove the pumping fluid reservoir bleed port screw. The pump inlet needs to be connected with users&#39; fab reservoir outlet or the in track reservoir outlet if it is provided. The pump outlet needs to be connected to the lab dispense outlet and an external digital valve  9  if it is provided. The external drain line needs to be connected from filter drain line to an outlet in the fab. Once power is supplied to the pump, the pump begins its auto balance procedure and since the piston  26  was at its 11 mL EOD position the pump will return to HRP by opening valve  8  and retracting. This process pulls 11 mL of air into the pumping fluid reservoir  32  and then continues with its auto balance processes. Once the pump  22  has completed the auto balance, (bearing in mind that this is where the user may need to perform a pressure sensor calibration since atm pressure is different at different altitudes) the user can now cap the pumping fluid reservoir bleed port BP 1 . At this point, the pump  22  is ready to complete the priming procedures and is close to being operational. 
     Customizeable Pressure Alarms 
     The pump system  20  also allows users to customize the overpressure setting for the pressure alarm according to operation pressure at the users&#39; location. Users can also set the duration for the over pressure alarm. Users can input the command “OVRPd,x” into the command line in the IDI or LYNX GUI for this purpose. “d” is the overpressure duration in ms. Users can set the value between 0 and 999 ms. “x” is the pressure limit to trigger the pressure alarm. There are two pressure values users can use; one is 28 psi, which can be represented by “1”; the other is 50 psi, which can be represented by “0”. For example, “OVRP125,1” sets overpressure duration to 125 ms @ 28 psi.” 
     Changing the Motor/Piston Assembly (Drive Assembly Change)— FIG. 26   
     The pump system  20  includes the ability to remove and replace the mechanical drive assembly  24  with inside without breaking the flow path. As mentioned previously, this drive assembly  24  ( FIGS. 8-9 ) comprises the electrical DC motor  24 E, lead screw  24 G, piston  26 , Polytetrafluoroethylene (PTFE) wiper ring  191  and accompanying hardware. The accompanying hardware includes the guide bearing  24 F, anti-rotation flag  56 , bolts  24 A- 24 D for holding down the motor  24 E and piston O-rings  74 . 
     The drive assembly  24  replacement is designed to take place with minimal disturbance to the pump system  20 . Drive assembly replacement requires the removal of the enclosure, the four motor mount bolts, motor power plug, and the pumping fluid reservoir bleed port BP 1  screw. 
     The drive assembly replacement process allows the drive assembly to be removed, repaired, and replaced without disturbing the process fluid flow path. This eliminates the risk of exposing the process fluid chemicals to air and other contaminants, and reduces the amount of process fluid and amount of requalification time needed to release the tool back into production. 
     The drive assembly replacement process ( FIG. 2 ) begins when the user enters the drive assembly change procedure in the connected software of microcontroller  38 . There are two ways that drive assembly replacement can be accomplished depending on the pump operation program interface: using the GUI or by using the RMVC subsystem operational interface 
     (1) Using the GUI ( FIG. 13A,13H or 13L )
         a. The pump  22  needs to be put in maintenance mode, which allows valve  5  to separate pumping fluid from the piston chamber  26  and process fluid chamber  34 B to be open. By typing the “SPCF 1 ” command in the command input line, this allows the pump  22  to enter into a special maintenance mode while closing valve V 5 , separating pumping fluid from the piston chamber  28  and pumping fluid chamber  34 A. At this stage the user needs to activate the push button switch  25 A ( FIG. 3 ), which is attached onto the PCB pressure board  48 , to the “ON” position to open valve  8 . That allows an open flow path for pumping fluid between the piston chamber  28  and pumping fluid reservoir  32 .   b. Next, the pumping fluid reservoir bleed port screw for port BP 1  needs to be removed. User needs to install the provided syringe ( FIG. 13 ) by screwing the male end to the pumping fluid reservoir bleed port BP 1 . The syringe plunger is drawn at end of the syringe. This allows air exchange between the pumping fluid reservoir  32  and the syringe chamber during the drive assembly replace process. The connection of the syringe also enables the pump  22  to move pumping fluid in the piston chamber  28  to the shoulder position  200  ( FIG. 10 ). By removing four bolts  24 A- 24 D holding down the motor  24 E and unplugging the motor power from PCB pressure board  48 , the drive assembly  24  can be gradually pulled out of piston chamber  26 .   c. Next, the user needs to slowly push air through the syringe to the pumping fluid reservoir  32  to raise the pumping fluid level in the piston chamber  26  approximately to the shoulder  200 . The new or repaired drive assembly with the piston located at the home position can be slowly inserted into the piston chamber  26 . The assembly should be oriented with the conical portion  76  of the piston  26  facing downward into the piston bore  28 . The motor  24 E should be oriented so that the wires that connect the motor to the pressure PCB  48  are located just above the pressure PCB  48 . The piston  26  should be oriented so that the anti-rotation flag  56  easily fits into the clearance channel and the conical section of the piston is centered in relation to the piston bore when the drive assembly is held vertically (electrical drive motor  24 E on top and piston  26  facing straight downward). The drive assembly  24  should be lowered until the conical section of the piston  26  is inside the piston bore  28  and the drive assembly  24  is resting on the lower (furthest from the electrical drive motor) O-ring  74 . The conical shape  76  of the piston  26  causes the pumping fluid and air to be displaced and the fluid level rises to completely fill the volume below the lower O-ring  74 .   d. Next, the four bolts  24 A- 24 D need to be reinstalled to hold down the motor  24 E, and the motor power needs to be plugged back on the PCB pressure board  48 . The syringe ( FIG. 13 ) can be removed by unscrewing it from the pumping fluid reservoir bleed port BP 1 .   e. Finally, the user can flip the switch that is attached to the PCB pressure board  48  back to the “OFF” position. This permits valve  8 , separating the piston chamber  28  and pumping fluid reservoir  32 , to be closed. By typing “SPCF 0 ” in the command input line, that disables the special maintenance mode and puts the pump  22  into regular maintenance mode by opening valve  5 . The auto-balance proceeds then needs to be conducted in order to ensure that the piston  26  is back to its reference home position HRP. Upon completion of the auto-balance, the user needs to reinstall the pumping fluid reservoir bleed screw back onto the pumping fluid reservoir bleed port BP 1 .       

     (2) Using the Remote Monitoring, Viewing &amp; Controlling (RMVC) Subsystem
     a. By using the RMVC subsystem operational interface ( FIGS. 13D-13G ), maintenance can be enabled by clicking on the “Enter/Exit Maintenance” button on the maintenance page. Under “Advanced” tab, it includes the drive assembly function. By clicking on “Change Drive Mechanism” tab, the drive assembly replacement procedures are shown on each following tabs. By clicking on “Enable Drive Change” tab, this closes valve  5 , separating the pumping fluid in the piston chamber  28  and process fluid chamber  34 A to separate pumping fluid in the piston chamber  28  and pumping fluid chamber  34 A while opening valve  8 , separating the piston chamber  28  and pumping fluid reservoir  32 .   b. At this point, the steps of 1(b)-1 (d) above for the “Using the GUI” are implemented.   c. For the last step, the user can click on the “Disable Motor Change” tab. This closes valve  8  and opens valve  5 . The user then clicks on the “Autobalance” tab to assist the piston  26  back to the home reference position HRP. Upon completion of the auto-balance procedure, the user needs to reinstall the pumping reservoir bleed screw back onto the pumping reservoir bleed port BP 1 .   

     Test of Gas Pressure in Piston Chamber after Drive Assembly Change in Track 
     This operation helps the user to determine if any air was introduced into piston chamber during the drive assembly change process. Before the drive assembly change, it is recommended to run the Gas in Piston Chamber Detection procedure ( FIG. 28 ). This process can be run at any time before the drive assembly change, for example, before or after the System Drain procedure has been run. This procedure goes through a series of steps which monitor the increase in pressure over the linear distance the piston travels. If the system experiences a pressure alarm within 0.1 mL of linear distance traveled or has a change in pressure over change in distance, DP/DX, of over, by way of example only, 5, then the piston chamber  28  is void of air. This assists the user in determining whether or not air was in the system prior to the drive assembly change and after the pump has been reassembled, the user again runs the Gas in Piston Chamber Detection procedure. The procedure indicates if air is in the piston chamber  28  after the drive assembly change. This gas detection sequence simply indicates to the user that if the system was void of air prior to the drive assembly change and if air is detected in the system after the drive assembly change, then the air was introduced during the drive assembly change itself. If the Gas in Piston Chamber Detection procedure detects air in the system after a motor assembly change, the user must re-run the drive assembly steps to ensure that there is no air in the piston chamber  28 . 
     Filter Cartridge Change: 
     A filter  42  is replaced by the user simply lifting up the release lever of the filter bracket and sliding out the old filter. The user slides in a new filter  42  and pushes down on the release lever which fixes and seals the filter  42  in place. The user then runs the PPRM 2  and PPRM 3  operations to fill and prime the filter housing and substrate and purge the filter of air. 
     Auto-Balance 
     The pump system  20  incorporates an auto-balancing (see flow chart in  FIG. 17 ) to equalize the pressure in the pump head(s) as well as to correct any inconsistency in the amount of fluid contained in the process fluid chamber(s) when the pump is in an “at-rest” position. This function allows the user to perform many maintenance functions without requiring the removal of the pump from the enclosure or the removal of the lower enclosure from its mounted position. This function also allows the pump to maintain a repeatable volume of fluid into the process fluid chambers, allowing for better control of the dispense characteristics of the pump and to prevent the possibility of damaging operations from occurring. The auto-balancing process every time power is applied to the pump or with the user starting the software process for this operation. The Auto-Balance begins its operation by checking if the piston is in the HRP. If the piston is not at HRP, the pump then opens valve  8  and pulls the piston  26  back to HRP while pulling pumping fluid out of the pumping fluid reservoir  32 . Once the piston is at HRP or if the piston  26  was originally at HRP, then the auto balancing procedure continues. The pump  20  then begins the next step by opening valve  8  and moving the piston  26  forward to push 4 mL of pumping fluid into the pumping fluid reservoir  32 . The pump  20  then closes valve  8  and opens valve  5  (the two isolation valves) and begins to retract the piston  26  to HRP while monitoring the pressure on the pressure sensor PS. The pump  20  stops if a pressure reading of negative 4.0 psi is detected or when reaching the HRP. If the pump  20  reaches a pressure of negative 4 psi, then the pump  20  continues with the auto balance, but if the pump reaches the HRP without reaching the desired pressure, then the pump  20  repeats the process of pushing fluid into the pumping fluid reservoir  32  via valve  8  and then closing valve  8  and opening valve  5  and recharging from the pumping fluid chamber  34 A until the desired negative pressure is reached. Once the desired pressure is reached, it closes valve  5  and opens valve  8  and returns the piston  28  to HRP pulling pumping fluid from the pumping fluid reservoir  32  and then closes valve  8 . The pump then opens valve  5  and moves the piston  26  forward to push 1.5 mL into the process fluid chamber  34 B and stops. The pump  20  then closes valve  5  and opens valve  8  and returns to HRP. At this time, the pump  20  is finished with the “Auto Balance” and has done all of the procedures needed to keep a consistent amount of pumping fluid into the pumping fluid chamber  34 A. 
     In particular, the head auto-balancing process begins with the user starting the software process of the microcontroller  38  for this operation. The pump controller  38  prompts the user to remove the pumping fluid reservoir bleed port screw from the universal elbow fitting located on the upper front face of the pump  22  (side of the pump body located farthest from the enclosure mounting bracket) at the port BP 1 . The pump controller  38  then opens the isolation valve  8  separating the piston chamber  28  from the pumping fluid reservoir  32 . The pump controller  38 , via the motor drive assembly  24 , then drives the piston  26  to the end of the dispense position (the farthest position from the at-rest home position, equal to the position stopped at during an 11 ml dispense) effectively emptying the piston chamber  28  of fluid. The pump controller  38  then closes the isolation valve  8  separating the pumping fluid reservoir  32  and the piston chamber  26  and opens the isolation valve  5  separating the piston chamber  26  and the process fluid chamber  34 A. 
     At this point, the pump controller  38  drives the piston  26  to enter a slow recharge movement towards the home position while the pump controller  38  continually monitors the pressure. Once the pressure transducer PS detects that the pressure in the chamber  28  is at atmospheric pressure (0 psig) the pump controller  38  continues to recharge, but at a reduced velocity. The piston  26  continues to return to the home position at the reduced rate until the pressure transducer PS detects a sufficiently negative pressure (negative pressure refers to the pressure differential between the internal pump body pressure and local atmospheric pressure; this is not a user variable). Once the internal pump body pressure reaches this level, the piston  26  begins to dispense at the same reduced velocity it recharged by. The pressure transducer PS again continually monitors the internal pump body pressure as the piston  26  dispenses. Once the pressure transducer PS indicates the internal pump body pressure equals atmospheric pressure, the piston  26  then stops. 
     The isolation valve  8  separating the piston chamber  28  and the pumping fluid chamber  32  closes and the isolation valve  8  separating the piston chamber and the pumping fluid reservoir  32  opens. The piston  26  then returns to the home position, pulling fluid from the pumping fluid reservoir  32 . Once the piston  26  has returned to the home position, all valves close and the pump controller  38  prompts the user to replace the pumping fluid reservoir bleed port screw at the port BP 1  to seal the pumping fluid reservoir  32 . 
     Dispense Detection 
     The dispense detection feature is intended to detect many of the common causes of wafer coating problems, including:
         Air in dispense line   Dispense/Suckback valve malfunction   Clogged nozzle   Kinked tubing   Dispense line Leaks       

     Dispense detection works by comparing the pressure profile for each dispense to a reference pressure profile. If the two profiles do not match within a user selectable sensitivity, the pump generates an alarm. 
     Whenever any change is made to a recipe, a new reference profile will be saved. The event log records each time a new reference profile is saved. 
     Operation: 
     The user begins running dispenses; the dispense detection is set and runs to record the Golden Sample after any change to a recipe. Once a Golden Sample is stored, any dispense that deviates by more than a user programmed percentage and number of counts out of the limits will stop the pump  20  and trigger an alarm. 
     Dispense Detection may be used with pressure sensor PS (or, e.g., Isense that models pump pressure based on motor current) providing the pressure profile data. 
     Pressure Sensor: 
     Pump chamber pressure is measured directly. 
     Isense Functionality: 
     Pump chamber pressure is inferred as described below. 
     Isense H/W: 
     Current is sensed via the voltage drop across the stepper motor driver sense resistors ( FIG. 14 ). Each phase is half-wave rectified with an active rectifier. The rectified signals are then summed and integrated. Stepper noise is removed with an envelope detector. The resulting signal is dc amplified and voltage translated such that the voltage window of interest is translated to the maximum limits of the A/D converter. This allows utilization of the maximum resolution of the A/D. Isense F/W: 
     Initial calibration is done by running the motor at each operating rate &amp; storing the unloaded “baseline” A/D value. 
     Motor load is obtained by subtracting the baseline from the present sample. This yields a value proportional to the motor load. This value is gain corrected for any non-linear &amp; rate related artifacts. 
     Alternate Dispense Detection Quality Reporting: 
     A dispense alarm occurs when any dispense deviates, from the reference dispense, by more than a user programmed percentage and number of counts out of the limits. 
     After each dispense, a “Dispense Quality” number is displayed. This number is shown as a percentage. If 100% of the dispense counts are within limits, “Dispense Quality”=100% is displayed. If 50% of the dispense counts are within limits, “Dispense Quality”=50% is displayed. The dispense may be divided into segments and each segment&#39;s “Dispense Quality” may be reported separately. 
     Alternative Embodiment Supporting Filter Recirculation and Nitrogen Supply to Gas Removal Reservoir 
       FIGS. 15 and 15A  depict an alternative embodiment of the precision pump system  20  that includes additional DIV valves ( 10 - 13 ) and venturi that permit the recovery of process fluid entrained within the filter  42  during a filter recirculation process. Typically, to remove the trapped gas in the filter  42  to the filter drain, process fluid entrained within the filter  42  is also discarded too. However, with the inclusion of valves  10  and  11 , it is possible to remove the trapped gas from the filter but to recirculate the trapped process fluid from the filter  42  back to the gas removal reservoir  30 . To further supplement this filter vent recirculation (FVR) process,  FIG. 15B  is provided which depicts the sequence of valves utilized to effect the FVR process. In particular, the first step is to determine whether the piston is at HRP and if it is, valves  1 ,  3 ,  5  and  10  are opened to advance the piston to displace 11 mL of process fluid; if the piston is not at HRP, a recharge operation ( FIG. 18 ) is performed first to establish HRP and then valves  1 ,  3 ,  5  and  10  are opened to displace the predetermined 11 mL of process fluid. Once that amount is displaced, those four valves are then closed and a recharge operation is performed. 
     In addition, should microcontroller  38  detect that all gas has been removed from the gas removal reservoir  30 , in order to re-establish a gas head within the gas removal reservoir  30 , a nitrogen N 2  source is coupled to the top of the gas removal reservoir  30  via a DIV valve  12 . The pump controller  38  can permit a predetermined amount of nitrogen to form a gas head within the gas removal reservoir  30 . This N 2  is pre-filtered before being delivered to the valve  12  and then to the gas removal reservoir  30  at a regulated 20 psi. 
     Gas Detection Algorithm and Gas Volume Detection Algorithm 
     The gas detection algorithm is required to automatically prime the filter  42 , and the gas volume detection algorithm is important for operation with the gas removal reservoir  30 . See  FIGS. 27A-27B  for Gas in Filter Detection Algorithm;  FIGS. 28A-28B  for Gas in Piston Chamber Detection Algorithm; and  FIGS. 29A-29B  for Gas Volume in Gas removal reservoir Detection Algorithm. 
     The sequences below refer to the distance rate of change of pressure (dp/dx) but they could also be made to work equally well using the time rate of change of pressure (dp/dt) as long as it is correlated back to the distance traveled based on the speed of travel of the piston  26 —since that ultimately correlates back to a volume change—and all of this is based on the ideal gas law correlating volumes and pressures of a gas that experiences a volume change without experiencing any significant change in temperature. 
     The key principal in both of these algorithms is that the piston  26  is advanced in a closed system and the rate of change of pressure is measured. Very high rates of change of the pressure (a pressure spike in the extreme case) indicate there is no gas, whereas low rates of change of the pressure indicate the presence of gas. The actual measured rate of change of pressure can be correlated back to empirically determined values (of rates of change of pressures) to determine an estimate of the amount or volume of gas in the system. 
     Gas Detection Algorithm (Typically Used to Determine the Presence of Gas in the Filter System, but can Also be Used to Test for the Presence of Gas after the Motor Change Feature) 
     1. Record the pre-charge pressure setting in a global variable 
     2. Set the pre-charge pressure to zero and wait for the pump chamber pressure to equalize to zero. This step isn&#39;t required but yields more consistent results, better results in general. 
     3. Close and open whatever valves are necessary to seal off the portion of the pump that needs to be tested for the presence of gas. 
     4. Measure the pressure and record it in a global variable 
     5. Advance the piston some distance (nominally 0.5 mL equivalent displacement); while the piston  26  is advancing execute these steps: 
     
         
         
           
             a. measure the instantaneous pressure and record it in a global variable 
             b. calculate the distance rate of change of pressure (dp/dx) based on the current pressure reading and the initial pressure reading and the position of the piston  26   
             c. if the rate of change of pressure (dp/dx) exceeds a threshold value (dp/dx&gt;5 typically indicates no presence of gas in the system) previously empirically determined to indicate no presence of gas in the system—then the system is determined to not have any gas present.
 
6. Alternatively a pressure alarm within a 10th of a milliliter of equivalent distance traveled would also indicate there is no gas trapped in the system. The optimal value can be empirically determined based on the physical makeup of the system.
 
7. if the piston advanced through the full test distance (nominally 0.5 mL of equivalent displacement) without having a pressure alarm or exceeding the threshold distance rate of change of piston chamber pressure—then that section of the pump is determined to have gas trapped in it.
 
8. Close and open whatever valves are necessary to bring the pump back to its ready state
 
9. set the pre-charge pressure to whatever it was before from the global variable that was used
 
10. the pump will take some amount of time to equalize back to the appropriate precharge pressure
 
           
         
       
    
     Gas Volume Detection Algorithm (Typically Used to Determine the Volume of Gas in the Gas Removal Reservoir  30 ) 
     1. Record the pre-charge pressure setting in a global variable 
     2. Set the pre-charge pressure to zero and wait for the pump chamber pressure to equalize to zero. 
     3. Close and open whatever valves are necessary to seal off the portion of the pump that needs to be tested to determine the volume of gas. 
     4. Measure the pressure and record it in a global variable. 
     5. Advance the piston some distance (nominally 1 mL equivalent displacement); while the piston  26  is advancing execute these steps: 
     
         
         
           
             a. measure the instantaneous pressure and record it in a global variable 
             b. calculate the distance rate of change of pressure based on the current pressure reading and the initial pressure reading and the position of the piston 
             c. if the rate of change of pressure exceeds a threshold value previously empirically determined to indicate no presence of gas in the system—then the system is determined to not have any gas present.
 
6. Alternatively a pressure alarm within a 10th of a milliliter of equivalent distance traveled would also indicate there is no gas trapped in the system. The optimal value can be empirically determined based on the physical makeup of the system.
 
7. If the piston advanced through the full test distance (nominally 1 mL of equivalent displacement) without having a pressure alarm or exceeding the threshold distance rate of change of piston chamber pressure—then that section of the pump is determined to have gas trapped in it. If the system is determined to have gas trapped in it then execute these steps:
 
             a. calculate the distance rate of change of pressure (dp/dx) over the piston displacement (nominally 1 mL of equivalent displacement) 
             b. volume=dp/dx*15 (approximately, and more data will be taken to get the best empirical correlation) 
             c. if the one milliliter displacement test determines that there is 20 mL or greater of gas in the system then another test can be run with a larger displacement to get a more accurate determination of the exact volume of gas trapped in the system.
 
8. Close and open whatever valves are necessary to bring the pump back to its ready state
 
9. set the pre-charge pressure to whatever it was before from the global variable that was used
 
10. the pump will take some amount of time to equalize back to the appropriate precharge pressure.
 
           
         
       
    
     It should be understood that the numerical terms in the above algorithms and in the accompanying  FIGS. 27A-29B  are approximate values that may be subject to change as the pump system is further developed. 
     It should also be noted that for the gas removal reservoir  30 , there are optional apparatus including:
         gas removal reservoir having an inlet for a nitrogen blanket (low pressure supply of nitrogen that is process filtered); see also  FIG. 15A .   there is a valve on the nitrogen blanket supply to turn it off or turn it on;   there is a check valve on the gas removal reservoir drain line biased to only allow flow out of the gas removal reservoir. This check valve can be located upstream or downstream of a typically located drain valve;   there is a venturi supply vacuum to pull fluid out of the drain line, or it may be needed to overcome any pressure differential that would tend to push fluid back from the drain line into the gas removal reservoir. The venturi has a nitrogen supply that also has a valve to turn off or turn on the nitrogen supply so that the venturi is not running all of the time.       

       FIG. 30  provides an overview of the major features of the present invention  20 , which are also discussed below. Moreover, one of key features of the present invention is a reservoir associated with the pump wherein the valves and any associated fluid control components for the reservoir are controlled by a microcontroller or other device that is in communication with or whose activities are coordinated with any controlling system associated with the pump. 
     Flow path continuity: This pump has a distinct advantage to others in the field when it comes to maintenance downtime. The use of a diaphragm pump with a pumping fluid and the ability to access a reservoir of this pumping fluid allows the pump  20  to move the fluid between chambers, if needed for repairs. On pump with multiple outputs, the user can change the filter, process fluid chamber diaphragm, or isolation valve on one output without affecting the others. 
     In track repair: The drive system can be easily replaced without the user needing to take the pump out of the coater/developer. This is made possible by the use of the pumping fluid reservoir and the conical piston head shape. The electronics enclosure is another item that can easily be replaced in the coater/developer. The wiring harness simply unplugs from the pump enclosure allowing it to remain in the coater/developer undisturbed while the electronics enclosure is replaced. It is also possible to change a pump head in the coater/developer as it can be drained of all process fluid and removed. Once the new head is attached to the pump body the system can be auto balanced and returned to production without breaking the flow path. 
     Predictive maintenance: The pump system  20  has the ability to detect and alert the user to a wearing system part. Different wear parts will cause different recognizable patterns in the dispense profile. The system will recognize these and alert the user of the need to replace the identified troublesome part. These parts include the drive system, the integrated diaphragmatic valves, and the filter. 
     Possible Detectable Faults: 
     Leaky piston O-rings 
     Air in Pumping Fluid 
     Air in Process fluid 
     Compressibility during pre-charge 
     Leaky diaphragmatic valves charge leak down 
     Filter excessive back pressure 
     Pump Chamber pressure exceeds limit 
     Lead screw back lash 
     Torque changes on motor reversal 
     Binding Lead screw/Motor 
     Increasing torque requirements 
     Digital valve binding 
     RMVC webcam 
     Dispense Detection: errors, graphs. The pump system has the ability to detect a good dispense by studying the profiles of the dispenses made. It alerts the user if a dispense is outside of the tolerance set by the user. The system also displays a graphical view of the data collected and how it compares to the baseline data set during the first dispense under the current dispense configuration. 
     Zero Loss Pump: The present invention is directed to achieving zero loss of process fluid by recirculating unused or undispensed process fluid to the gas removal reservoir  30 . 
     Pre-filtration by pulling a vacuum through the filter  42 : The gas removal reservoir  30  removes any gases (viz., air) that passes through the filter. 
     Gas removal reservoir Inlet Configuration: The process fluid source inlet is positioned on the roof of the gas removal reservoir where the side wall meets the roof on the shorter vertical side. The purpose of the source inlet&#39;s position is to allow for the process fluid to enter into the gas removal reservoir at an angle near the side edge which allows for the process fluid to smoothly run down the wall of the gas removal reservoir instead of dripping from the top of the reservoir, which can cause the capturing of air as the fluid falls. 
     Liquid Level Sensor (LLR) 
     When pre-filtering on a single stage pump, any gas that is generated (i.e., if the vapor pressure barrier is exceeded) is sent directly out the dispense tip. By pulling fluid through the filter and into the top of the gas removal reservoir (or near the bottom by using a sloped design), and then having the fluid flow out the bottom of the reservoir, any gas that was generated by the filter will be removed before exiting the reservoir. In order for the gas removal reservoir to work in a closed system, a gas/liquid interface inside the gas removal reservoir must be maintained. Some semiconductor manufacturing facilities do not allow for outside air to come in contact with the chemical to prevent contamination or particles from entering the process flow, so process grade N2 is used when needed. The amount of N2 and/or fluid can be managed within the reservoir with a program that measures the pressure exerted by the pump when pushing back to the gas removal reservoir, or by using a fluid level sensor (LLS), optical sensor, float sensor, flow meter, pressure sensor/meter, weight measurement device, visual, camera system, or any other means of determining the amount of fluid in the gas removal reservoir. 
     Gas Removal Reservoir Near the Pump (PRNTP) 
     During the startup phase and/or filter change, the filter and plumbing (tubing) needs to be wetted with fluid. One of the concerns was over the loss of liquids during this process. To minimize the effect, the system was designed around a (PRNTP) that will recirculate the liquid and remove any air that was in the system to start with or being generated by recirculation of normal filter venting. By filling from the top and pulling liquid out of the bottom of the (PRNTP), an air/liquid separation barrier is achieved (this could also be done by filling from the bottom and pulling liquid out of the bottom). If needed, a small vacuum (negative pressure) could be applied to further aid or speed up the air/liquid separation. The key to reducing liquid waste in the dispensing system is the ability to keep a prescribed amount of air/N2 in the (PRNTP) to allow for fluid to reenter the closed system, which is accomplished by allowing air/N2 to enter the (PRNTP) and/or making sure that there is sufficient air/N2 in the (PRNTP). The (PRNTP) also allows for any fluid released during normal venting of the filter to be sent back to it, thus keeping with a near zero loss of liquid objective. Air/N2 can be added to the system by adding a pressurized line, a pressurized regulated line, open air, vent or drain line. Some of the ways that the amount of air/N2 and/or liquid can be managed are with a program that measures the pressure exerted by the pump when pushing back to the (PRNTP), using a liquid level sensor (LLS), optical sensor, weight measurement device, float sensor, flow meter, pressure sensor/meter, visual, camera system, or any other means of determining the amount of fluid in the (PRNTP). 
     To do this, 1) all of the valves are closed. 2) Then valves  1  and  2  are opened. The pump head moves in a direction that will generate a vacuum drawing fluid into the (PRNTP), then into the pump head. Pump movement is repeated until the pump head is full. 3) Valves  1  and  2  are then closed. 4) Valves  3  and  4  are opened and the pump head moves in a direction that will generate a positive pressure pushing fluid into and through the filter. Steps 1) through 4) are repeated until the filter is completely wetted. To remove any air trapped inside the filter, steps 1) through 3) are performed. Step 5) opens valves  3  and  10  are opened and the pump head moves in a direction that will generate a positive pressure pushing air out of the filter (to the filter drain). Step 6) runs a program to determine if there is any air left in the filter, and then all valves are closed. Steps 1) through 3) and steps 5) through 6) are repeated until all air has been removed from the filter. To fill the (PRNTP) to the prescribed level, Steps 1) through 3) and steps 5) through 6) are repeated until completed. The last phase is to remove the air from the dispense tip. Step 7) closes all valves and then valves  1  and  2  are opened. The pump head moves in a direction that will generate a vacuum drawing fluid into the pump head. All valves are closed and then valves  3 ,  11  and  9  are opened. The pump head moves in a direction that will generate a positive pressure pushing fluid out the dispense tip. Repeat step 7) until all air is removed from the dispense line. This procedure allows for minimal if any loss of liquid during the startup phase, filter change, and/or normal dispense (where air is removed/vented from the filter on a predefined, automated, or manual schedule). 
     Ability to Use Pre/Post Filtration with One Pump-Moving Connections to the Filter 
     By incorporating the use of an (PRNTP), post filtration can be obtained as shown in the Gas removal reservoir Near The Pump (PRNTP) description where the filter is between the pump and the dispense tip. 
     By moving the connections to the filter where the filter is located before the (PRNTP), or any reservoir, gas generated from pulling a vacuum to create flow through the filter can be removed to provide for a bubble free dispense. Monitoring filter loading (differential pressure) can be done by measuring pressure with fluid in a new filter and comparing it to the readings obtained during normal use. Pressure readings can be obtained by using a pressure sensor in the pump, using a flow meter, monitoring the current on the motor, and/or with a pressure sensor located before the filter in the fluid path. 
       FIG. 31  depicts an alternative configuration wherein the filter is located before the gas removal reservoir  30  as well as the recirculation upstream of the filter  42 . In particular, the recirculation returns to a point upstream of the filter and downstream of an isolation valve. In this configuration, process fluid is pulled from the pumping chamber  34  through the filter  42  and into the gas removal reservoir  30 . Alternatively, a venturi on the gas removal reservoir drain can be used in combination with the gas volume detection system to fill the gas removal reservoir from the filter  42 . The gas removal reservoir  30  provides an extra degassing benefit from liquid being pulled through the filter  42 . In addition, precise control of the recharge rate can also mitigate any gas introduction. 
       FIG. 32  depicts another configuration wherein the filter  42  is located after the gas removal reservoir  30  and the recirculation is located either upstream of the gas removal reservoir  30 , or downstream of the gas removal reservoir (the latter alternative indicated by the valved path shown in phantom). Where the recirculation occurs upstream of the gas removal reservoir  30 , the recirculation line is coupled to a point upstream of the gas removal reservoir  30  and downstream of a closely-associated valve. Process fluid is pulled through the filter  42  directly during a recharge of the pump. Alternatively, when the valved path shown in phantom in  FIG. 32  is implemented, the recirculation line is coupled to a point upstream of the filter  42  and downstream of the gas removal reservoir  30  and a closely-associated valve. Process fluid is pulled through the filter  42  directly during a recharge of the pump. This valved path shown in phantom allows for isolation of the gas removal reservoir  30  and the filter  42  so that the filter  42  can be automatically tested for problems, e.g., unable to prime because of broken valve, leaking fitting (loss of seal). 
       FIG. 33  depicts another configuration wherein the filter  42  is also located before the gas removal reservoir but where the recirculation is downstream of the filter  42 . In particular, the recirculation returns to a point downstream of an isolation valve and upstream of the gas removal reservoir  30 , or directly into the top of the gas removal reservoir  30 . Process fluid is pulled from the pumping chamber  34  through the filter  42  and into the gas removal reservoir  30 . Alternatively, the venturi on the gas removal reservoir drain is used in combination with the gas volume detection system to fill the gas removal reservoir from the filter. The gas removal reservoir  30  provides an extra degassing benefit for the process fluid being pulled through the filter  42 ; again, precise control of the recharge rate can also mitigate any gas introduction. 
     It should be understood that in all cases of  FIGS. 31-33 , the gas removal reservoir  30  may include optional apparatus including:
         (1) gas removal reservoir  30  includes an inlet for a nitrogen blanket (e.g., a low pressure supply of nitrogen that is process-filtered);   (2) a valve on the nitrogen blanket supply to turn it off or turn it on;   (3) a check valve on the gas removal reservoir  30  drain line biased only to allow flow out of the gas removal reservoir. This check valve can be located upstream or downstream of a typically-located drain valve; and   (4) a venturi to supply vacuum to pull fluid out of the drain line, or it may be needed to overcome any pressure differential that would tend to push fluid back from the drain line into the gas removal reservoir  30 . The venturi has a nitrogen supply that also has a valve to turn off or turn on the nitrogen supply so that the venturi is not running all of the time.       

     Self-Correcting Pump 
     As with any single or dual stage pump, if the unit has a problem it may have to be addressed during unscheduled maintenance time. There is a need for a pump that has the ability to either self-repair/correct or to continue running until the scheduled maintenance time is available. This allows the pump to continue with production with the official downtime occurring during non-production or maintenance time. To accomplish this, the pump has the ability to measure the current applied to the pump motor. If the current increases over time with no change in the process setup or chemical, this could be the result of a problem with the output valve, electronics, motor, chemical, or filter. The pump could signal the operator that it needs to be looked at soon. If a flow meter is placed after the filter and before the dispense output/suckback valve, it can determine if the valve has opened or closed correctly. If the flow has changed, it could signal the pump to adjust the flow rate to the correct amount. If a flow meter is placed after the filter and after the dispense output/suckback valve, it can determine if the valve has opened or closed correctly, as well as, if suckback occurred correctly. If there is an issue with suckback, the pump could open the dispense valve slightly and then push or pull the fluid to bring the fluid back to the correct level. If the flow has changed for the dispense, it could signal the pump to adjust the flow rate to the correct amount. 
     Gas Evacuation Process 
     The system and method of the present invention  20  also implements a gas evacuation process whereby pressure is built up within the pump system (since air is compressible) and a quick vent process is performed to evacuate any air in the system  20 . In particular, there is shown in  FIGS. 34A and 34B  two gas evacuation processes, titled “GASE5” and GASE6″, respectively. The GASE5 process ( FIG. 34A ) is used as part of the fill routine (also referred to as the Recharge routine,  FIG. 18  discussed previously). The GASE6 ( FIG. 34B ) process is used as part of the recirculation routine. Other than the particular valves used in each process, the two gas evacuation processes are very similar. By way of example only, the gas evacuation threshold pressure is approximately 15 psi. Also by way of example only, the step of advancing the piston at a slow rate to build up pressure is approximately 0.1 mL/sec. 
     In view of the foregoing, Applicant has further improved upon the pump system of the present invention. To that end, there is shown in  FIG. 35  an alternative system configuration  1020  wherein the gas removal reservoir, hereinafter, the gas removal reservoir  1030 , comprises an internal vertical partition  1032  to further reduce the formation of air bubbles and improve the removal of air from the system while reducing the waste (i.e., discarding) of process fluid. In particular, as shown most clearly in  FIG. 35A , this improved pump system utilizes a redesigned gas removal reservoir  1030  that eliminates the raised top edge, or angled upper face of the gas removal reservoir  30 . The internal partition  1032  splits the gas removal reservoir  1030  into two smaller reservoirs, or sub-reservoirs, RS1 and RS2 with an open fluid channel  1036  connecting the two smaller reservoirs RS1/RS2 at the top of the reservoir  1030 , where the free end of the internal partition  1032  is located. The fluid inlet  1031  and a separate fluid outlet  1033  are both located at the bottom side of the reservoir  1030 ; when a pressure differential is created between the inlet  1031  and outlet  1033 , process fluid flow through the GRR  1030  is shown by the hatched line  1034 . Similarly, a vent/drain line (via valve  7 ) and a recirculation line (via valve  10 ) are each located on the top side of the gas removal reservoir  1030 , hereinafter referred to as the GRR  1030 . As such, the GRR  1030  maintains the advantage of collecting air bubbles  1035  at the top of the GRR  1030 , as the process fluid flow  1034  moves from the bottom side/inlet  1031  up and over the partition  1032  and then down towards the bottom side/outlet  1033 . The air bubbles  1035  are removed from the flowing process fluid  1034  in the open fluid channel  1036 , where they can be evacuated via the vent/drain lines (i.e., via valve  7 ). In addition, the alternative pump system  20 A has replaced the external filter block  40  ( FIG. 7 ) with an integrated valve configuration. 
     An even further alternative to the GRR  1030 , is the gas removal reservoir  1030 A, a functional diagram of which, is shown in  FIG. 35B . In particular, the internal vertical partition  1032  is replaced with a plurality of interdigitated partitions  1032 A that force the process fluid flow  1034 A into a sinusoidal flow around the ends of these partitions. The partitions  1032 A are located between the inlet  1031 A and the outlet  1033 A. As the process fluid flow  1034 A moves around the ends of these partitions  1032 A, as with the GRR  1030 , any air bubbles  1035 A will be separated above the upper open fluid channels  1036 A and vented via corresponding vent valves  7 A. In addition, any particulates P in the process fluid flow  1034 A will be deposited on the bottom surface of the GRR  1030 A underneath the lower ends of the partitions  1032 A connected to the top side of the GRR  1030 A. Thus, it is within the scope of the present invention  20 A to include the GRR  1030  or the multiple internal partition GRR  1030 A. It should be further understood that the five walls shown in  FIG. 35B  is by way of example only and that any number of plural partitions are within the broadest scope of this invention. 
       FIG. 35C  depicts a venturi circuit that can be implemented with the improved system  1020 . This venturi circuit along with the DIV valves  10 - 13  permits the recovery of process fluid entrained within the filter  42  during a recirculation process. In addition, should microcontroller  38  detect that all the gas has been removed from the GRR  1030  or  1030 A, in order to re-establish a gas head within the GRR  1030  or  1030 A, a nitrogen N 2  source is coupled to the top of the GRR  1030  via a DIV valve  12 . The pump controller  38  can permit a predetermined amount of nitrogen to form a gas head within the GRR  1030  or  1030 A. This N2 is pre-filtered before being delivered to the valve  12  and then to the GRR  1030  or  1030 A at a regulated 20 psi. 
       FIGS. 36A-36D  depict different views of the system  1020  showing the precision pump  1022  and its corresponding electrical control box  1023  that houses the electronics that control the pump  1022 , including the microcontroller  38  and the NMM  50  discussed previously. It should be understood that other than the presence of the GRR  1030  or  1030 A, the operation of the pump  1022  is similar to the operation of the pump  22  described previously. Furthermore, use of the prefix “10-” in the reference number in  FIGS. 36A-41  is meant to convey the corresponding function and operation of the items having reference numbers without that prefix, all of which were discussed earlier. 
       FIG. 37  is an exploded view depicting the internals of the pump  1022 . As with the first system  20 , the motor drive  24  sits atop a main pump assembly  1022 A and the motor drive  24  can be released from the main pump assembly  1022 A in a similar fashion described earlier with regard to system  20 . This figure shows the pump assembly  1022 A connected with the pump head  1022 B. The pressure sensor board  48 , also described earlier, is shown in  FIG. 37 , along with the maintenance button  25 A for initiating motor drive  24  removal. As can also be seen in  FIG. 37 , the filter distribution block  40  of the first system  20  has been replaced with an integrated configuration. The flare fittings  47  are shown on the pump  1022  and the pneumatic valve manifold  1044  operates similarly to the pneumatic valve manifold  44  described earlier. The pump  1022  is positioned within a housing H which receives a side cover SC and a top cover TC and bracket B and all of which can be releasably mounted using a mounting bracket MB. 
       FIGS. 38A-38B  depict opposite side perspective views of the pump head  1022 B and showing the dispense chamber  34 B.  FIG. 38C  depicts the alignment for coupling the pump head  1022 B with the pump assembly  1022 A.  FIGS. 38D-38F  depict the coupling of the pump assembly  1022 A and pump head  1022 B in more detail. 
       FIG. 39  is an exploded view of the pump head  1022  and shows the components, including the DIVs discussed earlier for controlling flows, as well as the relative location of the gas removal reservoir  1030  having the at least one internal vertical partition  1032 . The control side of the DIVs is on the plate  1080  which comprises the control port CP surrounded by the channel CH into which an O-ring  1081  is disposed. A diaphragm  1084  is disposed in between plate  1080  and surface  1080 A of the block  1078 . The output portion of the DIVs comprise the two outlet ports  1083 A and  1083 B, all in accordance with the DIV operation explained earlier. 
       FIG. 40A  is an isometric view of the pump head block showing the process fluid chamber side of the block, whereas  FIG. 40B  is an isometric view of the pump head block showing the gas removal reservoir and the side of the pump head block that mates with the valve plate.  FIG. 40C  is an enlarged perspective view diagrammatically showing the gas removal reservoir inlet.  FIG. 41  is a functional diagram showing how the pump head  1022 B interfaces with the filter  42 . 
       FIG. 42  provides an alternative pump system configuration  2020  that also achieves a minimum loss of process fluid. In particular, the system  2020  is similar to system  20 A except that a flow path  80  is provided from the vent of the filter  42  to the source line SL that feeds valve  1 . Furthermore, a separate vent  82  is provided at a high point or apex along the flow path  80 . The opening/closing of the vent  82  is controlled by the microcontroller  38  and can be opened/closed at a predetermined interval of time. This configuration  2020  avoids pushing process fluid out of the filter vent and into the filter drain. In operation, the fluid in the flow path  80  is a gas and liquid mixture that flows from the filter vent back towards the source line SL; during this flow, bubbles collect at the high point or apex of the fluid path  80  and are thus vented via the vent  82  via microcontroller  38  command. The airless process fluid is recirculated back to a “T”-type connection in the source line SL. This forces process fluid to flow back into the source line SL into the fab reservoir FB 
       FIG. 43  provides another alternative pump system configuration  3020  that also achieves a minimum loss of process fluid. In particular, the system  3020  is similar to system  1020  except that the vent  82  is replaced with a valve  90  and a separate filter vent-to-drain flow path  92 ; in addition, a bubble sensor  94  is inserted into the flow path  80 . The valve  90  and bubble sensor  94  are also positioned at a high point in the flow path  80 . Valve  90  is also controlled by the microcontroller  38 . In operation, the fluid in the flow path  80  is a gas and liquid mixture that flows from the filter vent back towards the source line SL; during this flow, bubbles collect at the high point or apex of the fluid path  80  and when the bubbles are detected by the bubble sensor  94 , the valve  90  is opened by the microcontroller  38  to vent the trapped air. The airless process fluid is recirculated back to a “T”-type connection in the source line SL. This forces process fluid to flow back into the source line SL into the fab reservoir FB. 
       FIG. 44  depicts a further pump system configuration  4020  wherein the pumping chamber  34  is coupled to the inlet of the GRR  1030 . In particular, the inlet  1031  of the GRR  1030  is coupled to valve  3  which is connected to the output of the process fluid chamber  34 B. The pump system configuration  4020  operates similarly to the system  1020 , but the difference is that the GRR  1030  is positioned downstream from the pump chamber and upstream of the filter  42 . The process fluid source (e.g., FAB reservoir FR) is directly coupled to the process fluid chamber  34 B via valve  1 . The pump chamber  34 B is also coupled to the input of the GRR  1030  via valve  2 . The output of the GRR  1030  is coupled to the inlet of the filter. The advantage of process fluid recovery and removal of air from the system is maintained with the system configuration  4020 . 
     It should be further understood that all of the previous routines/features described herein and disclosed in  FIGS. 16A-30  are applicable to all of the various system alternative embodiments described above, including the GASE5 and GASE6 gas evacuation processes. 
     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof