Method and apparatus for recycling process fluids

A method and apparatus for recycling a process fluid from a drain of a semiconductor process tool. The process fluid may be an acidic cobalt solution or an electroless cobalt solution used in a semiconductor process step to prevent electromigration in copper interconnects. The used process fluid is collected from the tool drain and recycled back to the tool inlet if a condition of the fluid is within a predetermined range. Otherwise, the used process fluid is drained from the system. The system may also operate in a bleed and feed mode where a portion of the used process fluid is periodically drained from the system.

FIELD OF THE INVENTION

The present invention is directed to a method and apparatus for recycling a process fluid from a semiconductor process tool. More particularly, the invention is directed to a method and apparatus for recycling or draining a used process fluid from a semiconductor process tool based upon a condition of the used process fluid.

BACKGROUND OF THE INVENTION

The manufacture of semiconductor devices is a complex process that can involve over 200 process steps. Each step requires optimal conditions to ultimately result in a high yield of semiconductor devices. Many process steps require the use of fluids to inter alia etch, clean, expose, coat, and polish the surface layers of the devices during manufacturing. In high purity fluid applications, the fluids (e.g. hydrofluoric acid, sulfuric acid, ammonium hydroxide, hydrogen peroxide, etc.) must be substantially free of particulate and metal contaminants in order to prevent defects in the finished devices. In chemical-mechanical polishing slurry applications, the slurries (e.g. Semi-Sperse®-12, iCue® 5001, Klebosole® 1501, Cab-O-Sperse® SC-112, etc.) must be free from large particles capable of scratching the surfaces of the devices. Moreover, during manufacturing there must be a stable and sufficient supply of the fluids to the process tools carrying out the various steps to minimize process variability and manufacturing downtime.

As semiconductor manufacturers design new devices in-line with the International Technology Roadmap for Semiconductors (ITRS) to produce smaller, faster and more reliable devices, new manufacturing challenges arise. Solutions to these challenges often require the use of novel or non-traditional fluids in the manufacturing process. An example of such a challenge is electromigration in copper interconnects. Electromigration occurs when electrons push and move the metal atoms in the direction of current flow at a rate determined by the current density. Electromigration can lead to thinning of the interconnect, high resistivity, or a line break. (see P. Singer, “The Advantages of Capping Copper with Cobalt,”Semiconductor International, October2005).

There are two known methods for eliminating electromigration in copper interconnects. One method is to form a cap on the interconnect by first depositing a palladium activation layer over the surface of the copper and then introducing an electroless cobalt solution to react with the palladium and form an electroless cobalt tungsten phosphide (CoWP) layer on the palladium. Another method is to use a self-activating process, which would not require deposition of palladium. In this process, a complex and unstable deposition fluid containing inter alia cobalt and acid is applied directly to the copper to form a cobalt cap layer on the copper. (see P. Singer, “The Advantages of Capping Copper with Cobalt,”Semiconductor International, October 2005). While these processes show promise to solve the problem of electromigration in copper interconnects, the cobalt solutions they employ are expensive particularly when such solutions are discarded after every use.

Semiconductor manufacturers historically have been reluctant to reclaim and recycle semiconductor process fluids primarily due to concern of contamination in the recycled fluids resulting from particles, metals and/or degradation of the fluid. Moreover, some fluids require a complex series of operations to be performed (e.g. distillation, adsorption, carbon filtration, etc.) before they are ready for reuse by a semiconductor tool. It may be that reclaim and recycle equipment costs and potential manufacturing downtime resulting from out of spec recycled fluid, have outweighed the gain of reclaiming and recycling the process fluids. However, with the emerging use of costly non-traditional solutions (e.g. the cobalt solutions mentioned above), there is a need for methods and apparatus for reclaiming and recycling semiconductor process fluids.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention provides a method of recycling a process fluid comprising the steps of: reclaiming used process fluid from a drain of a semiconductor process tool wherein the used process fluid flows from the drain and into a reclaim line; measuring a condition of the used process fluid with a fluid sensor connected to the reclaim line; sending a signal indicative of the condition from the fluid sensor to a controller and determining if the signal is within a predetermined range; and recycling the used process fluid to the semiconductor process tool if the signal is within the predetermined range or diverting at least a portion of the used process fluid to a system drain if the signal is outside of the predetermined range.

In another aspect, the invention provides an apparatus for recycling a process fluid from a semiconductor process tool comprising: a reclaim line connected to a drain of the semiconductor process tool for reclaiming used process fluid; a fluid sensor connected to the reclaim line for measuring a condition of the used process fluid; a recycle line for recycling the used process fluid from the reclaim line to an inlet of the semiconductor process tool; a tank positioned in the recycle line, the tank having an inlet for receiving the used process fluid from the reclaim line; a controller adapted to receive a signal indicative of the condition from the fluid sensor and to determine if the signal is within a predetermined range wherein if the signal is within the setpoint range the controller is adapted to send a signal to a valve to direct the used process fluid to the tank and if the signal is outside of the setpoint range the controller is adapted to send a signal to the valve to direct the used process fluid to the system drain; and a fluid distribution means connected to the tank and to the inlet of the semiconductor process tool.

In another aspect, the invention is directed to a system for recycling an acidic cobalt solution comprising: a semiconductor process tool adapted to prevent electromigration in copper interconnects by applying the acidic cobalt solution to the copper interconnects; and a recycling system comprising: a reclaim line connected to a drain of the semiconductor process tool for reclaiming used acidic cobalt solution; a conductivity probe connected to the reclaim line for measuring conductivity of the used acidic cobalt solution; a recycle line for recycling the used acidic cobalt solution from the reclaim line to an inlet of the semiconductor process tool; a tank positioned in the recycle line, the tank having an inlet for receiving the used acidic cobalt solution from the reclaim line; a controller adapted to receive a signal indicative of the conductivity and to determine if the signal is within a predetermined conductivity range wherein if the signal is within the conductivity range the controller is adapted to send a signal to a valve to direct the used acidic cobalt solution to the tank and if the signal is outside of the conductivity range the controller is adapted to send a signal to the valve to direct the used acidic cobalt solution to the system drain; and a fluid distribution means connected to the tank and to the inlet of the semiconductor process tool.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention are shown inFIGS. 1 and 2. The invention is directed to a system for recycling a used process fluid reclaimed from a drain of a semiconductor process tool. The reclaimed process fluid is either recycled back to an inlet of the process tool if a condition of the used process fluid is within a predetermined range or drained from the system. In one embodiment, the invention provides a blending and distribution and recycle and reclaim system that supplies used process fluid to a point of use (e.g. a semiconductor process tool). More specifically, the invention provides an apparatus and method for blending at least two fluids to form a semiconductor process fluid, distributing the mixture to a semiconductor process tool at a sufficient pressure for semiconductor processing, reclaiming the mixture and, based upon certain parameters, either recycling or draining the mixture.

FIG. 1shows an embodiment of the recycling system100according to the present invention. Used process fluid exits the tool115through one or more drain lines117aand117b. The fluid may exit the tool by gravity, or the tool115may include a sump pump for transferring used process fluid into the one or more drain lines117aand117b. As shown inFIG. 1, each drain line splits into two separate flow paths119and121at valves129aand129b. Alternatively, the drain lines117aand117bmay tee together and in this configuration, only one valve (129aor129b) would be used; operation of the system would be substantially the same as the two valve configuration. The used process fluid is reclaimed by flowing through flow path119(“the reclaim line”) and back into tank103. However, if certain conditions exist (as will be further discussed below), the used process fluid will be diverted to drain line121to flow into a drain system123such as an acid-base neutralization system. The three-way valves129aand129bmay be used to selectively divert the flow of used process fluid through either the reclaim line119or the drain line121.

As shown inFIG. 1, the reclaim line119includes a sensor125to monitor a condition of the used process fluid in the reclaim line119. Alternatively, a sensor may be placed in each drain line117aand117bupstream of valves129aand129b. The sensor125is preferably a conductivity probe that monitors the conductivity of the used process fluid. However, other sensors may also be used such as a pH probe, an ORP probe, a densitometer, an autotitrator or a refractive index sensor. Notably, a combination of sensors may be installed in reclaim line119(or drain lines117aand117b) to monitor the used process fluid; for example, a conductivity probe and densitometer may be installed in reclaim line119(or drain lines117aand117b). Sensor125may be electrically or wirelessly connected to a controller127(e.g. a programmable logic controller) which monitors the signal output from sensor125. Controller127may also be either electrically, wirelessly, or pneumatically connected to the other components of the system including the flow controllers109,111, the pump113, and the valves129a,129b,131.

A pump113(e.g. a reciprocating pump, a positive displacement pump, a bellows pump, a centrifugal pump, etc.) may be positioned in the recycle line112to draw the process fluid from tank103and deliver the process fluid at a specified pressure to the semiconductor process tool115. Notably, the process fluid in the tank may be a mixture of used process fluid from the drain lines117and fresh process fluid from line110. Tool115may include one or more spray heads and the recycle line112of system100can be configured to supply one or more tools. The pressure requirements of such tools range from about 5 to about 60 psi.

When the fluid level in the tank103is low, a first flow controller109supplies a first fluid and a second flow controller111supplies a second fluid to the tank103. The first flow controller109is connected to first fluid supply line101while the second flow controller111is connected to second fluid supply line105. The first fluid may be pressurized deionized water, for example, supplied by an on-site water purification plant. The first fluid may also be ammonium hydroxide, hydrogen peroxide, or an additive or diluent supplied by any pressurized source. The second fluid may be any fluid used for a process step in a semiconductor spray-head tool. The second fluid may be, for example, an acidic cobalt solution supplied by a bulk fluid blending and/or distribution system107such as those manufactured by the BOC Edwards™, Inc. Chemical Management Division (Chanhassen, Minn.). The second fluid may also be hydrofluoric acid, sulfuric acid, ammonium hydroxide, hydrogen peroxide or the like, or Semi-Sperse-12 (“SS-12”), iCue 5001, Klebosol 1501 (“K-1501”), Cab-O-Sperse SC-112 (“SC-112”) or other like fluids.

The first and second fluids may be blended together using one of several blending techniques including weight-based blending, volumetric-based blending and flow controller blending. Examples of weight-based blending are described in U.S. Pat. Nos. 6,098,843; 6,269,975; 6,340,098 and 6,675,987. Examples of volumetric-based blending are described in U.S. Pat. Nos. 5,632,960; 5,370,269; 5,490,611 and 5,803,599.FIG. 1shows an embodiment of the invention using flow controller blending; however, it should be noted that the above-listed weight-based or volumetric-based blending techniques may be substituted for the flow controller blending technique described herein.FIG. 1shows that the flow rates of the first and second fluids are controlled by flow controllers109and111, respectively. Examples of suitable flow controllers include the LiquiSys™ manufactured by BOC Edwards, Inc. or other flow controllers manufactured by NT International, PLC or Entegris®, Inc. The flow rates of each fluid may also be controlled by peristaltic pumps, metering valves, totalizing flow meters, or the like. Tank103is preferably constructed of an inert wetted material such as perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), polyvinylchloride (PVC), polyvinylidine difluoride (PVDF), or polyethylene (PE), for example, and can include one or more level sensors104such as capacitive, optical, or digital sensors or load cells.

During operation system100forms a mixture of the first fluid and the second fluid by controlling the flow rates of each fluid with flow controllers109and111. For example, the second fluid may be a concentrated acidic cobalt solution that requires dilution to 10% with deionized water (i.e. the first fluid in this example) prior to semiconductor processing in the tool115. Accordingly, flow controller111may control the flow rate of the cobalt solution at 10 ml/min while flow controller109controls the flow rate of the deionized water at 100 ml/min in order to achieve the desired concentration or mix ratio. Notably, the rate of blending should exceed the rate of pumping so that fluid mixture is available for the tool115at all times. Thus, the flow rates of the first and second fluids may be increased or decreased depending upon the flow rate demand of the tool115.

In a preferred embodiment, as shown inFIG. 1, fluid lines101and105are connected upstream of tank103so that the first and second fluid are already combined when entering tank103rather than entering the tank as individual components. System100may include a mixing device, such as an in-line static mixture, downstream of the tee to ensure that there is sufficient mixing of the two fluids prior to entering tank103. In another embodiment, the fluid lines101and105may be individually connected to tank103and mixing of the fluids would then occur in the tank through a mixing device, like a stirrer, or through turbulence.

Moreover, another sensor (e.g. conductivity probe, pH probe, ORP probe, autotitrator or refractive index sensor) may be configured to monitor a characteristic of the fluid mixture in tank103and transmit a signal to controller127. For example, if an autotitrator is used, a pump may periodically draw a sample from tank103(or from a point just downstream from tank103or pump112) into the autotitrator. The autotitrator would then perform a titration on the sample to determine the concentration of a component (e.g. hydrogen peroxide) in the fluid mixture. If the concentration of the component is outside of a predetermined range, then controller127would activate the flow controller (109or111) on the supply line (101or105) for that component to add an additional volume of that component to the fluid mixture. The system100may also be configured so that the controller127sends a signal to another device for dosing the component into tank103from a pressurized line other than supply lines101or105. In this configuration, the pressurized line may be fed by a blending and/or distribution system or by a small dosing or metering pump drawing fluid from a drum.

System100may also include level sensors104to ensure that tank103maintains a sufficient volume of fluid mixture in the tank103and to prevent overfill or overpressurization of the tank103. For example, tank103may include four capacitive sensors to monitor low-low, low, high and high-high levels of the tank. During operation, the fluid mixture is withdrawn from tank103by pump113and the tank is refilled from one of two sources. Tank103may receive fresh fluid mixture from line110or used process fluid from line120. As will be further discussed below, used process fluid will normally flow through reclaim line119and back into tank103. However, used process fluid will also be periodically bled from system100through drain line121. Thus, the fluid level in tank103will decrease over time. When the fluid level in tank103reaches a low set point (e.g. determined by a low sensor or a predetermined weight), the controller127will activate the flow controllers109and111to refill tank103with fresh fluid mixture to a high set point (e.g. determined by a high sensor or a predetermined weight).

In one embodiment, the pump113withdraws the fluid mixture from tank103and dispenses it to one or more points of use, such as semiconductor process tool115, at a predetermined pressure (e.g. typically about 5 to about 60 psi). After processing, the used process fluid flows through the tool drain line117aor117b. If the system100is operating in a reclaim mode, the fluid flows through the normally open port of valve129aor129band past sensor125. Sensor125monitors a condition (e.g. conductivity, pH, etc.) of the used process fluid and sends a signal to controller127. If the signal is within a predetermined range, then the controller will maintain valve131in its normally open position thereby permitting the used process fluid to flow into tank103. However, if the signal is outside the predetermined range, then the used process fluid is diverted to drain line121and to the manufacturing plant's drain system. If the fluid is reclaimed, it flows into tank103and combines with a mixture of fresh blended and/or pre-used fluid. This mixture is then recycled through the pump113and back to the tool115for further processing.

If the system100is operating in a drain mode, the used process fluid will flow through drain line117aor117band through the normally closed ports of valves129aor129binto drain system123. This mode may be useful if a tool operator desires to drain the system100and remove all reclaimed fluid. In addition, system100may enter the drain mode when the level of the fluid mixture in tank103reaches the high level thereby making tank103unable to accept more fluid.

System100may also operate in a bleed and feed mode. During this mode, controller127may be configured to activate one or more of valves129a,129bor131at periodic time intervals. For example, the controller may be configured to activate valves129aand129bevery 5 minutes for a period of 30 seconds thereby diverting a portion of the used process fluid to drain123. Similarly, the controller127may be configured to periodically activate valve131to bleed used process fluid from system100. System100may also be configured to have a mechanical bleed and feed. For example, inFIG. 1, a slipstream line (e.g. a ¼ inch tube) may be installed downstream from valve131and the slipstream line would tee into drain line121. The slipstream line may include an orifice (e.g. 0.100 inch orifice) which would permit a portion of the used process fluid to continuously flow to the drain system123. In addition, the bleed and feed operation may also be based upon the signal received from sensor125such that if a measured condition of the fluid (measured by sensor125) is outside of a predetermined range, the controller127will activate valve131(or valves129aand129b) to divert used process fluid to the drain system123for a predetermined period of time or until the measured condition is back within the predetermined range.

System100may operate in an on-line or on-demand mode. When operating in an on-line mode, the pump continuously supplies the fluid mixture from tank103to the one or more points of use and continuously reclaims or drains the used process fluid using one of the above described modes: the reclaim mode, the drain mode and/or the bleed and feed modes. In an on-demand mode, the controller127is configured to receive a demand signal from the one or more points of use and activate the pump113to supply fluid mixture to a point of use upon receipt of the demand signal.

It should be noted that system100is user configurable. The controller127may include a human machine interface (HMI) which would permit a user or operator to select the desired modes of operation.

Another embodiment of the present invention is shown inFIG. 2. Used process fluid exits tool215through one or more drain lines217aand217b. The fluid may enter drain lines217aand217bby gravity or tool215may include one or more sump pumps for transferring the used process fluid into the drain lines217aand217b. In the embodiment shown inFIG. 2, drain lines217aand217bsplit into two flow paths219and221at valves229aand229b. Alternatively, drain lines217aand217bmay tee and in this configuration, only one valve (229aor229b) would be used; operation of system200would be substantially the same as the two valve configuration. The used process fluid can be reclaimed by flowing through flow path219(“the reclaim line”) and back into tank203. However, if certain conditions exist, the used fluid is diverted to drain line221to flow into a drain system223such as an acid-base neutralization system. Three-way valves229aand229bmay be used to selectively divert the used process fluid through either the reclaim line219or the drain line221. Another filter226may be installed in the reclaim line219to filter out any particles resulting from processing or from flow through process tool215.

A sensor225is installed in reclaim line219and monitors a condition of the used process fluid in the line219. Alternatively, a sensor may be installed in each drain line217aand217bupstream of valves229aand229b. Sensor225is preferably a conductivity probe, but could also be a pH probe, an ORP probe, a densitometer, an autotitrator or a refractive index sensor. Notably, numerous sensors may be installed in reclaim line219to monitor the condition of the fluid; for example, a conductivity probe and a densitometer may be installed in the reclaim line219. Sensor225may be electrically or wirelessly connected to a controller227(e.g. a programmable logic controller) which monitors an output signal from sensor225. Controller227may also be electrically, wirelessly, or pneumatically connected to the other components of the system including the flow controllers209,211, the pump213, and the valves229a,229b,231and233.

System200includes a pump213(e.g. a reciprocating pump, a positive displacement pump, a bellows pump, a centrifugal pump, etc.) for drawing fluid from tank203and delivering the fluid at a predetermined pressure (e.g. between about 5 and about 60 psi) to one or more points of use such as a semiconductor process tool215. Notably, tool215may include one or more spray heads and the pump distribution line212of system200can be configured to supply one or more tools. A filter214may be installed in pump distribution line212to filter the fluid mixture prior to processing.

First and second fluid supply lines201and205respectively supply first and second fluids to tank203. The first fluid (e.g. pressurized deionized water, ammonium hydroxide, hydrogen peroxide, any additive, any diluent, etc.) may be supplied by an on-site plant, or by any pressurized source. The second fluid (e.g. an acidic cobalt solution, hydrofluoric acid, sulfuric acid, ammonium hydroxide, hydrogen peroxide or the like, or SS-12, iCue 5001, K-1501, SC-112 or other like fluids) may be supplied by a bulk fluid blending and/or distribution system or by any pressurized source.

As mentioned above with respect to the first embodiment, the first and second fluids may be blended using weight-based blending, volumetric-based blending or flow controller blending. While any one of these techniques may be employed in system200,FIG. 2shows an embodiment of the invention using flow controller blending. Flow controllers209and211are installed in supply lines201and205, respectively, to control the flow rates of the first and second fluids. However, as mentioned above with respect to system100, peristaltic pumps, metering valves, totalizing flow meters or the like may be used instead of flow controllers. Tank203is preferably constructed of an inert wetted material (e.g. PFA, PTFE, PVC, PVDF, or PE), and can include one or more level sensors204such as capacitive, optical, or digital sensors or load cells.

During operation system200forms a mixture of the first and second fluids by controlling the flow rates of each fluid with flow controllers209and211. For example, the second fluid (e.g. a concentrated acidic cobalt solution) may require dilution with the first fluid (e.g. deionized water) to about 10% prior to semiconductor processing in the tool215. Thus, flow controller211could control the flow rate of the second fluid at 10 ml/min while flow controller209controls the flow rate of the first fluid at 100 ml/min in order to achieve the desired concentration or mix ratio. Notably, the rate of blending should exceed the rate of pumping so that the fluid mixture is available for the tools at all times. Thus, the flow rates of the first and second fluids may be increased or decreased depending upon the flow rate demand of the tool215.

In a preferred embodiment, as shown inFIG. 2, fluid lines201and205are connected upstream of tank203so that the first and second fluid are combined prior to entering tank203. System200may include a mixing device, such as an in-line static mixture, downstream of the tee to ensure that there is sufficient mixing of the two fluids prior to entering tank203. In another embodiment, the fluid lines201and205may be individually connected to tank203so that mixing of the fluids would occur in the tank through a mixing device, like a stirrer, or through turbulence.

Moreover, another sensor (e.g. conductivity probe, pH probe, ORP probe, autotitrator or refractive index sensor) may be configured to monitor a characteristic of the fluid mixture inside of tank203and transmit a signal to controller227. For example, if an autotitrator is used, a pump may periodically draw a sample from tank203(or from a point just downstream from tank203or pump213) into the autotitrator. The autotitrator would then perform a titration on the sample to determine the concentration of a component (e.g. hydrogen peroxide) in the fluid mixture. If the concentration of the component is outside of a predetermined range, then controller227would activate the flow controller (i.e.209or211) on the supply line (i.e.201or205) for that component to add an additional volume of that component to the fluid mixture. The controller227may also be configured to send a signal to another device for dosing the desired component into tank203from a pressurized line other than supply lines201or205. In this configuration, the pressurized line may be fed by a blending and/or distribution system or by a small dosing or metering pump drawing fluid from a drum.

Tank203may include level sensors204for ensuring that the tank maintains a sufficient volume of fluid mixture and to prevent overfill or overpressurization of the tank203. For example, tank203may include two load cells for measuring a low weight and a high weight. During operation, the fluid mixture is withdrawn from tank203by pump213and the tank is refilled from one of three sources. Tank203may receive fresh fluid mixture from line210, used process fluid from line220, or recirculated fluid mixture from line235. As will be further discussed below, used process fluid will normally flow through reclaim line219and back into tank203. However, used process fluid will also be periodically bled from system200through drain line221. Thus, the fluid level in tank203will decrease over time. When the fluid level in tank203reaches a low set point (e.g. determined by a low sensor or a predetermined weight), the controller227will activate the flow controllers209and211to refill tank203with fresh fluid mixture to a high set point (e.g. determined by a high sensor or a predetermined weight).

During operation pump213withdraws the fluid mixture from tank203and dispenses it at a predetermined pressure (e.g. typically about 5 to about 60 psi) to one or more points of use, such as semiconductor process tool215. Used process fluid flows through one or both drain lines217aand217band to respective valves229aand229b. If system200operates in a reclaim mode, the used process fluid flows through the normally open port of valve229aor229band past sensor225. Sensor225monitors a condition of the used process fluid and sends a signal to controller227. If the signal is within a predetermined range, then the controller maintains valve231in its normally open position thereby permitting the used process fluid to flow into tank203. However, if the signal is outside the predetermined range, then the used process fluid is diverted to drain line221and to the manufacturing plant's waste neutralization system. If the used process fluid is reclaimed, it flows into tank203and combines with a mixture of fresh blended and/or pre-used fluid. This mixture is then recycled through pump213and back to tool215for further processing.

If the system is operating in a drain mode, the used process fluid will flow through drain line217aor217band through the normally closed ports of valves229aor229binto drain system123. This mode may be useful if a tool operator desires to drain the system200and remove all reclaimed fluid. In addition, system200may enter the drain mode when the level of the fluid mixture in tank203reaches the high level thereby making tank203unable to accept more fluid.

System200may also operate in a bleed and feed mode. During this mode, controller227may be configured to activate one or more of valves229a,229bor231at periodic time intervals. For example, the controller may be configured to activate valves229aand229bevery 5 minutes for a period of 30 seconds thereby diverting a portion of the used process fluid to drain223. System200may also be configured to have a mechanical bleed and feed. For example, a slipstream line (e.g. a ¼ inch tube) may be installed downstream from valve231and the slipstream line would tee into drain line221. The slipstream line may include an orifice (e.g. 0.013″ orifice) which would permit a portion of the used process fluid to continuously flow to the drain system223. In addition, the bleed and feed operation may also be based upon the signal received from sensor225such that if a measured condition of the fluid (measured by sensor225) is outside of a predetermined range, the controller227will activate valve231(or valves229aand229b) to divert used process fluid to the drain system223for a predetermined period of time or until the measured condition is back within the predetermined range.

System200operates in an on-line mode such that the pump213operates continuously to either supply the fluid mixture from tank203to one or more points of use or to recirculate the fluid mixture back to the tank203. When the controller227receives a demand signal from a point of use, the controller227activates valve233so that the fluid mixture flows through the normally closed port of valve233and to the point of use. Simultaneously, the system200either reclaims or drains the used process fluid using one of the above described modes: the reclaim mode, the drain mode and/or the bleed and feed modes. When there is no tool demand, valve233is deactivated and the fluid flows through the normally open port of valve233and back into tank203. Recirculation back to tank203ensures optimal performance of filter214to maintain the concentration of particles at a low level.

Like system100, system200is user configurable. The controller227may include a human machine interface (HMI) which would permit a user or operator to select the desired modes of operation.

Notably, in alternative embodiments, systems100and200may include two tanks. While one tank is in an on-line mode and either recirculating or dispensing the fluid mixture, the other tank would be in a blend and qualification mode. During the blend and qualification mode, the controller127or227would initiate a blend sequence to fill the off-line tank and then initiate a qualifying sequence including measuring a condition of the fluid mixture in the off-line tank with a conductivity probe, a pH probe, an ORP probe, an autotitrator or a refractive index sensor. If the condition was outside a predetermined range, the controller127or227would activate one of the flow controllers (109,111or209,211) or another pressurized source to add additional fluid to the off-line tank, and then the controller127or227would re-measure the condition of the fluid in the off-line tank. The controller127or227may also be configured to give an error message when the off-line tank is out of specification. Once qualified, the off-line tank would wait idle until the level of the fluid in the on-line tank reaches its low level and then the tanks would switch operational modes.

Moreover, although the use of filters has only been described with respect to system200, filters could also be installed in the embodiment of the invention shown inFIG. 1. Moreover, while both embodiments were described as blending two fluids supplied by pressurized lines101and105or201and205, either system100or200can be configured to blend two or more pressurized fluids supplied by two or more supply lines either upstream of tanks103or203or in tanks103or203. In addition, either system100or system200may further include a system drain line in the pump distribution lines112or212. In this configuration, a three-way valve would be installed in the recycle line112or212and the controller127or227would periodically activate this valve to bleed fluid mixture from the system100or200to the drain system123or223.

Furthermore, it should be noted that systems100and200may be located on a different level of the semiconductor manufacturing plant than the tool115or215or the fluid blending and/or distribution systems107. For example, a fluid distribution system may be located in the basement and may supply pressurized fluid to system100or200which is located on a level above the basement in the “sub-fab.” In addition, the tool may be located above system100or200in the “fab.”

The present invention as described above and shown in the embodiments ofFIGS. 1 and 2provides a cost effective solution for recycling semiconductor process fluids. The invention further provides a system for blending and distribution and reclaiming and recycling a semiconductor process fluid. It is anticipated that other embodiments and variations of the present invention will become readily apparent to the skilled artisan in light of the foregoing description and examples, and it is intended that such embodiments and variations likewise be included within the scope of the invention as set forth in the following claims.