Source: http://www.google.co.uk/patents/US20070128048
Timestamp: 2017-11-23 17:01:56
Document Index: 7674822

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US20070128048 - System and method for position control of a mechanical piston in a pump - Google Patents
Embodiments of the systems and methods disclosed herein utilize a brushless DC motor (BLDCM) to drive a single-stage or a multi-stage pump in a pumping system for real time, smooth motion, and extremely precise and repeatable position control over fluid movements and dispense amounts, useful in semiconductor...http://www.google.co.uk/patents/US20070128048?utm_source=gb-gplus-sharePatent US20070128048 - System and method for position control of a mechanical piston in a pump
Publication number US20070128048 A1
Also published as US8083498, US8678775, US9309872, US20120070313, US20140127034
Publication number 11602485, 602485, US 2007/0128048 A1, US 2007/128048 A1, US 20070128048 A1, US 20070128048A1, US 2007128048 A1, US 2007128048A1, US-A1-20070128048, US-A1-2007128048, US2007/0128048A1, US2007/128048A1, US20070128048 A1, US20070128048A1, US2007128048 A1, US2007128048A1
Original Assignee George Gonnella, James Cedrone, Iraj Gashgaee
Patent Citations (99), Referenced by (39), Classifications (8), Legal Events (7)
US 20070128048 A1
a brushless DC motor driving a dispense pump residing in said pump;
a processor communicatively coupled to said computer-readable medium and said pump, wherein said software instructions are executable by said processor to control said brushless DC motor in accordance with a control scheme.
5. The pumping system of claim 3, wherein said position sensor is operable to provide measurements that facilitate control of said piston at 0.045 degrees of rotation.
8. The pumping system of claim 1, wherein said control scheme is configured to run said brushless DC motor at least two controller frequencies during a single cycle.
9. The pumping system of claim 8, wherein said at least two controller frequencies comprises a first frequency for a dispense portion of said single cycle.
10. The pumping system of claim 9, wherein said first frequency is at 30 kHz.
11. The pumping system of claim 1, wherein said control scheme is configured to provide a desirable dispense profile characterized by smoothness of a pressure signal.
12. The pumping system of claim 1, wherein said control scheme is configured to run said brushless DC motor at a first frequency during dispensing and drop down to a second frequency during non-dispensing operations.
13. The pumping system of claim 1, wherein said pump is a single-stage pump or a multi-stage pump.
wherein said brushless DC motor is controlled by software instructions embodied on a computer-readable medium and executable by a processor implementing a control scheme and wherein said processor is communicatively coupled to said computer-readable medium and said pump.
15. The pump of claim 14, further comprising a position sensor coupled to said brushless DC motor and in communication with said processor for providing real time position feedback of said piston.
16. The pump of claim 15, wherein said position sensor is internally or externally coupled to said brushless DC motor.
17. The pump of claim 15, wherein said position sensor is operable to provide measurements that facilitate control of said piston at 0.045 degrees of rotation.
18. The pump of claim 14, wherein said control scheme is configured to minimize heat generation by running said brushless DC motor at least two controller frequencies during a single cycle, wherein said at least two controller frequencies comprises a first frequency for a dispense portion of said single cycle.
19. A method of controlling position of a mechanical piston in a pump, comprising:
connecting said mechanical piston to a brushless DC motor;
employing a position sensor for real time position feedback of said mechanical piston; and
controlling an operating frequency of the control loop of said brushless DC motor according to software instructions implementing a control scheme,
wherein said software instructions are embodied on a computer-readable medium and executable by a processor,
wherein said processor is communicatively coupled to said computer-readable medium and said pump,
wherein said control scheme increases said operating frequency of said brushless DC motor to enhance position control of said mechanical piston during dispensing and decreases said operating frequency of said brushless DC motor during non-dispensing operations to minimize heat generation.
20. The method of claim 19, further comprises increasing said operating frequency of said brushless DC motor to about 30 kHz during a dispense portion of a cycle.
21. The method of claim 19, further comprises decreasing said operating frequency of said brushless DC motor to about 10 kHz during a non-dispense portion of a cycle.
22. The method of claim 19, wherein said pump is a single-stage or a multi-stage pump.
In operation, multi-stage pump 100 can include a ready segment, dispense segment, fill segment, pre-filtration segment, filtration segment, vent segment, purge segment and static purge segment (see FIG. 4). During the feed segment, inlet valve 125 is opened and feed stage pump 150 moves (e.g., pulls) feed stage diaphragm 160 to draw fluid into feed chamber 155. Once a sufficient amount of fluid has filled feed chamber 155, inlet valve 125 is closed. During the filtration segment, feed-stage pump 150 moves feed stage diaphragm 160 to displace fluid from feed chamber 155. Isolation valve 130 and barrier valve 135 are opened to allow fluid to flow through filter 120 to dispense chamber 185. Isolation valve 130, according to one embodiment, can be opened first (e.g., in the “pre-filtration segment”) to allow pressure to build in filter 120 and then barrier valve 135 opened to allow fluid flow into dispense chamber 185. According to other embodiments, both isolation valve 130 and barrier valve 135 can be opened and the feed pump moved to build pressure on the dispense side of the filter. During the filtration segment, dispense pump 180 can be brought to its home position. As described in the U.S. Provisional Patent Application No. 60/630,384, entitled “SYSTEM AND METHOD FOR A VARIABLE HOME POSITION DISPENSE SYSTEM” by Laverdiere, et al. filed Nov. 23, 2004 [Atty. Dkt. No. ENTG1590], and PCT Application No. PCT/US2005/042127, entitled “SYSTEM AND METHOD FOR VARIABLE HOME POSITION DISPENSE SYSTEM”, by Laverdiere et al., filed Nov. 21, 2005, [Atty. Dkt. No. ENTG1590/PCT], both of which are incorporated herein by reference, the home position of the dispense pump can be a position that gives the greatest available volume at the dispense pump for the dispense cycle, but is less than the maximum available volume that the dispense pump could provide. The home position is selected based on various parameters for the dispense cycle to reduce unused hold up volume of multi-stage pump 100. Feed pump 150 can similarly be brought to a home position that provides a volume that is less than its maximum available volume.
As fluid flows into dispense chamber 185, the pressure of the fluid increases. The pressure in dispense chamber 185 can be controlled by regulating the speed of feed pump 150 as described in U.S. patent application Ser. No. 11/292,559, entitled “SYSTEM AND METHOD FOR CONTROL OF FLUID PRESSURE,” by Gonnella et al., filed Dec. 2, 2005, [Atty. Dkt. No. ENTG1630] both of which are incorporated herein by reference. According to one embodiment of the present invention, when the fluid pressure in dispense chamber 185 reaches a predefined pressure set point (e.g., as determined by pressure sensor 112), dispense stage pump 180 begins to withdraw dispense stage diaphragm 190. In other words, dispense stage pump 180 increases the available volume of dispense chamber 185 to allow fluid to flow into dispense chamber 185. This can be done, for example, by reversing dispense motor 200 at a predefined rate, causing the pressure in dispense chamber 185 to decrease. If the pressure in dispense chamber 185 falls below the set point (within the tolerance of the system), the rate of feed motor 175 is increased to cause the pressure in dispense chamber 185 to reach the set point. If the pressure exceeds the set point (within the tolerance of the system) the rate of feed motor 175 is decreased, leading to a lessening of pressure in downstream dispense chamber 185. The process of increasing and decreasing the speed of feed motor 175 can be repeated until the dispense stage pump reaches a home position, at which point both motors can be stopped.
FIG. 3 is a diagrammatic representation of a pumping system 10 embodying multi-stage pump 100. Pumping system 10 can further include a fluid source 15 and a pump controller 20 which work together with multi-stage pump 100 to dispense fluid onto a wafer 25. The operation of multi-stage pump 100 can be controlled by pump controller 20. Pump controller 20 can include a computer readable medium 27 (e.g., RAM, ROM, Flash memory, optical disk, magnetic drive or other computer readable medium) containing a set of control instructions 30 for controlling the operation of multi-stage pump 100. A processor 35 (e.g., CPU, ASIC, RISC, DSP, or other processor) can execute the instructions. Pump controller 20 can be internal or external to pump 100. Specifically, pump controller may reside onboard multi-stage pump 100 or be connected to multi-stage pump 100 via one or more communications links for communicating control signals, data or other information. As an example, pump controller 20 is shown in FIG. 3 as communicatively coupled to multi-stage pump 100 via communications links 40 and 45. Communications links 40 and 45 can be networks (e.g., Ethernet, wireless network, global area network, DeviceNet network or other network known or developed in the art), a bus (e.g., SCSI bus) or other communications link. Pump controller 20 can be implemented as an onboard PCB board, remote controller or in other suitable manner. Pump controller 20 can include appropriate interfaces (e.g., network interfaces, I/O interfaces, analog to digital converters and other components) to allow pump controller 20 to communicate with multi-stage pump 100. Pump controller 20 can include a variety of computer components known in the art, including processors, memories, interfaces, display devices, peripherals or other computer components. Pump controller 20 can control various valves and motors in multi-stage pump to cause multi-stage pump to accurately dispense fluids, including low viscosity fluids (i.e., less than 100 centipoire) or other fluids. An I/O interface connector as described in U.S. Provisional Patent Application No. 60/741,657, entitled “I/O INTERFACE SYSTEM AND METHOD FOR A PUMP,” by Cedrone et al., filed Dec. 2, 2005, [Atty. Dkt. No. ENTG1810], describes an I/O adapter that can be used to connected pump controller 20 to a variety of interfaces and manufacturing tools.
The opening and closing of various valves can cause pressure spikes in the fluid. Closing of purge valve 140 at the end of the static purge segment, for example, can cause a pressure increase in dispense chamber 185. This can occur, because each valve may displace a small volume of fluid when it closes. Purge valve 140, for example, can displace a small volume of fluid into dispense chamber 185 as it closes. Because outlet valve 147 is closed when the pressure increases occur due to the closing of purge valve 140, “spitting” of fluid onto the wafer may occur during the subsequent dispense segment if the pressure is not reduced. To release this pressure during the static purge segment, or an additional segment, dispense motor 200 may be reversed to back out piston 192 a predetermined distance to compensate for any pressure increase caused by the closure of barrier valve 135 and/or purge valve 140. One embodiment of correcting for pressure increases caused by the closing of a valve (e.g., purge valve 140) is described in the U.S. Provisional Patent Application No. 60/741,681, entitled “SYSTEM AND METHOD FOR CORRECTING FOR PRESSURE VARIATIONS USING A MOTOR”, by Gonnella et al., filed Dec. 2, 2005 [Atty. Dkt No. ENTG1420-3] incorporated herein by reference.
Pressure spikes in the process fluid can also be reduced by avoiding closing valves to create entrapped spaces and opening valves between entrapped spaces. U.S. Provisional Patent Application No. 60/742,168, entitled “METHOD AND SYSTEM FOR VALVE SEQUENCING IN A PUMP,” by Gonnella et al., filed Dec. 2, 2005, [Atty. Dkt No. ENTG1740], describes one embodiment for timing valve openings and closings to reduce pressure spikes in the process fluid.
It should be further noted that during the ready segment, the pressure in dispense chamber 185 can change based on the properties of the diaphragm, temperature or other factors. Dispense motor 200 can be controlled to compensate for this pressure drift as described in the U.S. Provisional Patent Application No. 60/741,682, entitled “SYSTEM AND METHOD FOR PRESSURE COMPENSATION IN A PUMP”, by James Cedrone, filed Dec. 2, 2005, [Atty. Dkt. No. ENTG1800], incorporated herein by reference. Thus, embodiments of the present invention provide a multi-stage pump with gentle fluid handling characteristics that can avoid or mitigate potentially damaging pressure changes. Embodiments of the present invention can also employ other pump control mechanisms and valve linings to help reduce deleterious effects of pressure on a process fluid. Additional examples of a pump assembly for multi-stage pump 100 can be found in U.S. patent application Ser. No. 11/051,576 entitled “PUMP CONTROLLER FOR PRECISION PUMPING APPARATUS”, by Zagars et al., filed Feb. 4, 2005 [Afty. Dkt. No. ENTG1420-2] incorporated herein by reference.
Dispense block 4005 can also include various external inlets and outlets including, for example, inlet 4010 through which the fluid is received, purge/vent outlet 4015 for purging/venting fluid, and dispense outlet 4020 through which fluid is dispensed during the dispense segment. Dispense block 4005, in the example of FIG. 10, includes the external purge outlet 4010 as the pump only has one chamber. U.S. Provisional Patent Application No. 60/741,667, entitled “O-RING-LESS LOW PROFILE FITTING AND ASSEMBLY THEREOF” by Iraj Gashgaee, filed Dec. 2, 2005, [Atty. Dkt. No. ENTG1760], which is hereby fully incorporated by reference herein, describes embodiments of o-ring-less fittings that can be utilized to connect the external inlets and outlets of dispense block 4005 to fluid lines.
Dispense block 4005 routes fluid from the inlet to an inlet valve (e.g., at least partially defined by valve plate 4030), from the inlet valve to the pump chamber, from the pump chamber to a vent/purge valve and from the pump chamber to outlet 4020. A pump cover 4225 can protect a pump motor from damage, while piston housing 4027 can provide protection for a piston and can be formed of polyethylene or other polymer. Valve plate 4030 provides a valve housing for a system of valves (e.g., an inlet valve, and a purge/vent valve) that can be configured to direct fluid flow to various components of pump 4000. Valve plate 4030 and the corresponding valves can be formed similarly to the manner described in conjunction with valve plate 230, discussed above. Each of the inlet valve and the purge/vent valve is at least partially integrated into valve plate 4030 and is a diaphragm valve that is either opened or closed depending on whether pressure or vacuum is applied to the corresponding diaphragm. Alternatively, some of the valves may be external to dispense block 4005 or arranged in additional valve plates. In the example of FIG. 10, a sheet of PTFE is sandwiched between valve plate 4030 and dispense block 4005 to form the diaphragms of the various valves. Valve plate 4030 includes a valve control inlet (not shown) for each valve to apply. pressure or vacuum to the corresponding diaphragm.
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Cooperative Classification F04B49/065, F04B17/03, F04B25/00, Y10S417/90