Polishing fluid recovery and reuse system for semiconductor substrate processing

Abstract

A polishing system (100), a fluid reuse system (500) and a method of polishing a substrate. The polishing system includes a sump (200), a vacuum device (400), and a polishing fluid recovery module (501) for recovering a polishing fluid. The sump is sized to surround and abut a polishing pad (104) secured to the platform (102). The radially inward facing surface of the sump is further defined by an arcuate radius equal to the arcuate radius of the platform that the sump is dimensioned to surround, the radially inward facing surface of the sump configured to allow the polishing fluid to flow radially outward from the polishing pad into the slot. The systems and methods collect and reuse polishing fluid used during chemical mechanical polishing (CMP) processes for manufacturing electronic devices.

Description

Technical Field

[0001] Embodiments described herein relate generally to systems and methods for processing semiconductor substrates during electronic device manufacturing, and more particularly to systems for collecting and reusing polishing fluids used in chemical mechanical polishing (CMP) of semiconductor substrates and substrate processing methods related thereto. Background Art

[0002] Chemical mechanical polishing (CMP) is commonly used in the manufacture of high density integrated circuits (e.g., semiconductor devices) to planarize or polish a layer of material deposited on a substrate. A typical CMP process includes contacting the material layer of the substrate to be planarized with a polishing pad and moving the polishing pad, the substrate, or both, thereby generating relative movement between the surface of the material layer and the polishing pad in the presence of a polishing fluid. Material is removed from the surface of the material layer in contact with the polishing pad via a combination of chemical and mechanical action, which is provided at least in part by the polishing fluid. Commonly used polishing fluids include slurries (e.g., colloids or suspensions) containing abrasive particles, reactive liquid (abrasive-free) slurries, and abrasive-free or reduced-abrasive polishing fluids used in conjunction with fixed abrasive polishing pads having abrasive particles disposed therein.

[0003] Typically, polishing fluids are highly engineered to provide the desired chemical and mechanical polishing performance characteristics, and are engineered to disperse and maintain the abrasive particles in a colloidal or relatively stable suspension. Due at least in part to the high cost of engineering and manufacturing CMP polishing fluids, CMP processing is typically the most expensive substrate processing operation in semiconductor device manufacturing.

[0004] Therefore, in order to reduce the costs associated with polishing fluids used in semiconductor device manufacturing, there is a need in the art for a method and system for collecting and reusing polishing fluids used in a semiconductor substrate polishing process. Summary of the invention

[0005] The present disclosure generally relates to methods and systems for collecting and reusing polishing fluid used during a chemical mechanical polishing (CMP) process in the manufacture of electronic devices.

[0006] In one embodiment, a polishing system is disclosed. The polishing system includes a sump that is sized to surround and abut a polishing pad fixed to a platform. The sump includes an inner wall, an outer wall radially disposed outward from the inner wall, and a base connecting the inner wall to the outer wall. The base is configured to couple the sump to the platform so that the sump rotates with the platform and the polishing pad. The outer wall, the inner wall, and the base together define a groove. The radially inward-facing surface of the sump is further defined by an arc radius that is equal to the arc radius of the platform that the sump is sized to surround. The inward-facing surface of the sump is configured to allow polishing fluid to flow radially outward from the polishing pad into the groove. The polishing system further includes a vacuum device that includes a suction pipe. The suction pipe is disposed within the groove of the sump and is spaced apart from the base. The suction pipe is fixed relative to the rotating sump. The polishing system further includes a polishing fluid recovery module. The suction pipe draws the polishing fluid out of the tank and sends the polishing fluid to the polishing fluid recovery module for reuse.

[0007] In another embodiment, a fluid recycling system is disclosed. The system includes a platform, a polishing pad fixed to the platform, and a first and a second closed loop control slurry delivery system (CLCSDS). The first CLCSDS delivers a first polishing fluid to the polishing pad, wherein the first polishing fluid is collected by a polishing fluid sump. The polishing fluid sump includes an inner wall, an outer wall radially disposed outward from the inner wall, and a base connecting the inner wall to the outer wall. The base is configured to couple the sump to the platform so that the sump rotates with the platform. The outer wall, the inner wall, and the base collectively define a groove. The radially inwardly facing surface of the sump is defined by an arc radius that is equal to the radius of the platform around which the sump is sized. The fluid recycling system further includes a vacuum device that includes a suction pipe. The suction pipe is disposed within the groove of the sump and is spaced apart from the base. The suction pipe is fixed relative to the rotating sump, allowing the vacuum device to collect the first polishing fluid. The fluid recycling system further includes a polishing fluid recovery module. The polishing fluid recovery module is configured to recover the first polishing fluid into the second polishing fluid. The second polishing fluid is provided to the second CLCSDS. The second CLCSDS delivers the second polishing fluid to the polishing pad. The first polishing fluid can be delivered to the polishing pad simultaneously by the first CLCSDS so that a mixture of the first polishing fluid and the second polishing fluid can be used, or alternatively the flow of the first polishing fluid can be stopped and the polishing pad is supplied only with the second polishing fluid.

[0008] In another embodiment, a method of polishing a substrate is disclosed. The method includes dispensing a polishing fluid onto a surface of a polishing pad; pushing a substrate against the surface of the polishing pad while rotating a platform having a polishing pad disposed thereon; collecting the polishing fluid using a fluid recycling system; filtering contaminants in the polishing fluid; and dispensing the polishing fluid collected using a polishing fluid sump onto the surface of the polishing pad. The fluid recycling system includes a sump coupled to the platform. The sump is configured to abut the platform and rotate with the platform. At least some of the polishing fluid dispensed onto the polishing pad is collected in a groove of the sump. The polishing fluid is collected by a vacuum device comprising a suction tube disposed within the groove.

[0009] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to enable the above-mentioned features of the present disclosure to be understood in detail, a more specific description of the present disclosure briefly summarized above may be obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure, as the present disclosure may admit to other equally effective embodiments.

[0011] Figure 1 is a schematic side view of a polishing system configured with a sump (shown in cross section) according to an embodiment.

[0012] Figure 2 According to an embodiment, Figure 1 A schematic cross-sectional perspective view of a portion of a sump is shown in FIG.

[0013] Figure 3 is a schematic side view of a sump (shown in cross section) according to an embodiment.

[0014] Figure 4A is a schematic perspective view of a vacuum device according to an embodiment.

[0015] Figure 4B is a schematic side view of a vacuum device according to an embodiment.

[0016] Figure 5A and Figure 5B is a schematic diagram of a fluid reuse system according to an embodiment.

[0017] Figure 6 is a schematic diagram of a polishing fluid recovery module of a fluid reuse system according to an embodiment.

[0018] Figure 7 According to the embodiment, Figures 1 to 6 Schematic diagram of a waste collection system for use with a fluid sump is shown in FIG.

[0019] Figure 8 is a schematic diagram of a controller unit configured to control a fluid reuse system and a waste collection system according to an embodiment.

[0020] Fig. 9 is a flow chart of a method of utilizing a fluid reuse system according to an embodiment.

[0021] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of each embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0022] Embodiments of the present disclosure generally provide a system for collecting and reusing polishing fluid, and methods related thereto. Specifically, the systems and methods provided herein feature a polishing fluid collection system for collecting and reusing polishing fluid dispensed during chemical mechanical polishing (CMP) of a substrate in an electronic device manufacturing process.

[0023] In a conventional CMP process, a polishing fluid is dispensed onto the surface of a polishing pad mounted on a rotating platform. The polishing fluid is dispensed onto the surface of the polishing pad, and the substrate is pushed against the polishing pad in the presence of the polishing fluid. The dispensed polishing fluid is distributed radially outward from the dispense location by the centrifugal force imparted to the polishing fluid by the rotation of the platform. When the polishing fluid reaches the circumferential edge of the polishing pad, the polishing fluid typically flows into a drainage pool that surrounds the platform and extends to an area disposed below the platform. This helps capture all fluids and other processing byproducts used during CMP substrate processing and other processing activities that follow (e.g., pad rinsing and pad conditioning activities, and polishing byproducts associated therewith). Typically, the volume of non-polishing fluid far exceeds the volume of polishing fluid, such as more than 5 times. Therefore, the effluent from the drainage pool typically contains highly diluted and contaminated polishing fluid. Therefore, embodiments of the present invention provide a polishing fluid capture system for capturing the polishing fluid before it otherwise flows into the drainage pool, thereby avoiding any contamination and dilution thereof.

[0024] Attempts to recycle polishing fluid have been largely unsuccessful, at least in part due to the relatively low concentration of polishing fluid in the pool effluent and the variation in its composition. In addition, the polishing process typically uses more than one type of polishing fluid, each of which is delivered to the polishing pad in sequence at different stages of the polishing process. The chemical compositions and abrasives used in each of the different polishing fluids may be incompatible with each other, further complicating the effluent handling and recovery processes. Advantageously, the embodiments provided herein are configured to selectively capture used polishing fluid closer to the polishing process (i.e., before the used polishing fluid flows into the drain pool), and reuse the captured polishing fluid without the need for further costly processing. Therefore, the embodiments provided herein can be used to substantially reduce the cost per substrate polished during the semiconductor device manufacturing process.

[0025] In one aspect, the polishing system herein includes a sump disposed adjacent to a rotatable platform. The sump is sized to surround and abut the platform and is configured to be coupled to the platform so that the sump rotates with the platform. A vacuum device is disposed within a groove of the sump and is fixed relative to the rotating sump. The vacuum device is used to suck polishing fluid out of the groove of the sump and into a polishing fluid recovery module for recovering the polishing fluid.

[0026] Figure 1 1 is a schematic side view of a polishing system 100 according to one embodiment. Here, the polishing system 100 includes a cylindrical platform 102; a polishing pad 104, for example, secured to the platform using a pressure sensitive adhesive; a substrate carrier 106 disposed on the platform 102 to face the polishing pad 104; and a sump 200 for collecting and recovering polishing fluid from a polishing process. During a typical process, the substrate carrier 106 pushes a material surface of a substrate 108 disposed in the substrate carrier 106 against the polishing pad 104 while rotating about a carrier axis 110. The platform 102 rotates about the platform axis 112 while the rotating substrate carrier 106 sweeps back and forth from the inner diameter to the outer diameter of the platform 102 to partially reduce uneven wear of the polishing pad 104. In some embodiments, the polishing system 100 further includes a pad conditioner assembly (not shown) for wearing, regenerating, and removing polishing byproducts or other debris from the surface of the polishing pad 104.

[0027] As shown, polishing fluid, polishing fluid additives, cleaning fluid and / or deionized (DI) water are delivered from a polishing fluid source 126 to a fluid dispensing arm 114 located above the platform 102 and dispensed onto the polishing pad 104 using a nozzle 116 located in the fluid dispensing arm. The fluid dispensing arm 114 is coupled to an actuator 118, which positions the fluid dispensing arm on the platform 102 by swinging the fluid dispensing arm over the platform 102. The actuator 118 is disposed on a base plate 120 surrounding the platform 102. As discussed further below, a system controller 800 controls the actuator, the amount of polishing fluid dispensed by the fluid dispensing arm 114, and a fluid reuse system 500 (discussed below).

[0028] See also Figure 2 and Figure 3 , water collection tank 200 (in Figure 1 The sump 200 is sized to surround and abut the polishing pad 104. The sump 200 includes an inner wall 210, an outer wall 212, and a base 214. The outer wall 212 is disposed radially outward from the inner wall 210. The base 214 connects the inner wall 210 to the outer wall 212. The inner wall 210, the outer wall 212, and the base 214 collectively define a groove 202, which is Figure 1 200, i.e., the inner wall 210, the outer wall 212, and the base 214 are formed of a polymer having a hydrophobic surface that is resistant to polishing fluid chemistry. Examples of suitable polymers include fluoropolymers (fluoropolymers), such as perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE) (which can be used as In some embodiments, the base 214 of the sump 200 is an annular ring that surrounds the platform 102 and is fixedly coupled to the platform 102. The base 214 is configured to have a plurality of holes 22 configured to receive a plurality of fasteners 220. The fasteners couple the sump 200 to the platform 102 so that the sump 200 rotates with the polishing pad 104 about the platform axis 112.

[0029] The sump 200 collects polishing fluid that is rotated radially outward from the rotating polishing pad 104 due to the centrifugal force applied to the rotating polishing pad 104. In one embodiment, the diameter of the sump is about 2 feet. The outer wall 212 is separated from the inner wall 210 by the width W(1) of the groove 202, which is between about 0.5 cm and about 5 cm. The combined width W(2) of the thickness of the groove 202 and the inner wall 210 is between about 1 cm and about 6 cm. The inner wall 210 and the outer wall 212 each extend a height H(1) from the base 214 in the Z direction, although different heights may be used for each wall. The radially inner facing surface 230 of the sump 200 is further defined by an arc radius that is equal to the arc radius of the polishing pad 104 that the sump 200 is sized to surround. This allows all of the polishing fluid to flow radially outward from the surface of the polishing pad 104 into the grooves 202 and not fall between the sump 200 and the polishing pad 104 .

[0030] Referring to FIG. 4 , the sump 200 further includes a vacuum device 400. The vacuum device 400 includes a suction tube 402. The sump 200 does not include a gravity-type drain or opening that can be used to discharge the polishing fluid from the tank 202. The fluid collection efficiency of a gravity-type drainage system may be insufficient because the liquid is dispersed over a large surface area, resulting in slow drainage. The suction tube 402 is disposed in the tank 202 of the sump 200. The suction tube 402 is spaced apart from the base 214 to avoid wear on the suction tube 402 while still allowing sufficient suction. Therefore, the polishing fluid system is extracted from the tank 202 using the suction tube 402. The vacuum device 400 is configured to be stationary relative to the rotating sump 200, although it is conceivable that the tube may have the ability to control its movement by an actuating device to optimize fluid collection or remove the collection tube for use. The vacuum device 400 is supported by a portion of the polishing system 100 that does not rotate with the platform 102, such as by using a bracket 410. As the polishing fluid flows from the polishing pad 104 into the groove 202 , the vacuum device 400 draws the polishing fluid out of the groove 202 .

[0031] In some embodiments, the sump 200 is coupled to a Z actuator that is configured to raise and lower the sump 200 in the Z direction. In those embodiments, the radially inwardly facing surface 230 of the sump 200 is defined by an arc radius that is greater than the arc radius of the polishing pad 104 that the sump 200 is sized to surround. The inner wall 210 is further configured to include a lip 240 to span a gap between the arc radius of the radially inwardly facing surface 230 of the sump 200 and the arc radius of the polishing pad 104. In those embodiments, the sump 200 is raised when fluid that is not desired to be reused is dispensed onto the polishing pad 104. In the raised position, the radially inwardly facing surface 230 and the lip 240 block fluid from flowing out of the edge of the polishing pad from entering the groove 202 of the sump 200. Thus, fluid that is not intended to be reused flows through the gap defined by the radially inwardly facing surface 230 of the sump 200 and the arc radius of the polishing pad 104, and enters the drainage sump 122 (eg, Figure 1 ). When polishing fluid that is desired to be reused is dispensed onto polishing pad 104, sump 200 is lowered to a fluid collection position and the polishing fluid that is desired to be reused is collected using the methods described herein.

[0032] See also Figure 5A, a fluid recycling system 500 is illustrated. The fluid recycling system 500 includes a polishing fluid recovery module 501 and one or more polishing systems 100. The fluid recycling system 500 further includes a first closed loop controlled slurry delivery system (CLCSDS) 502 and a second CLCSDS 504. The first CLCSDS 502 delivers a first polishing fluid 506 from a polishing fluid source 126 to a polishing pad 104 of one of the polishing systems 100 via a fluid distribution arm 114. The polishing fluid source 126 includes a centralized or localized polishing fluid distribution system used by a manufacturing facility to deliver the first polishing fluid 506 to the polishing system 100. The first polishing fluid 506 from the polishing fluid source 126 is typically not yet used in a substrate CMP processing operation. Subsequently, the first polishing fluid 506 is collected by the sump 200 and is extracted from the sump 200 by the vacuum device 400. The polishing fluid recovery module 501 collects the first polishing fluid 506 extracted from the trough 202 of the sump 200 via the vacuum device 400, and recovers / filters the first polishing fluid 506 to form a second polishing fluid 508. Subsequently, the second polishing fluid 508 is provided to the second CLCSDS 504 for delivery to the platform. When the second polishing fluid 508 is delivered to the platform 102, the flow of the first polishing fluid 506 can be stopped by the first CLCSDS 502 so that the system 500 can continue to operate using the second polishing fluid 508. Alternatively, the flow rate of the first polishing fluid 506 and the flow rate of the second polishing fluid 508 can be adjusted to provide a mixture of the first polishing fluid 506 and the second polishing fluid 508 to the platform 102. This allows the first polishing fluid 506 to be provided for any losses in the collection process, as well as for preferential process tuning of the mixing ratio of the first polishing fluid 506 and the second polishing fluid 508 to achieve optimal substrate 108 polishing. In another embodiment, as Figure 5B As shown in FIG. 5 , the system 500 includes a static mixer 560 for premixing a first polishing fluid 506 and a second polishing fluid 508 before delivering the polishing fluids to the platform 102 .

[0033] In one embodiment, as shown in Figure 6, the polishing fluid recovery module 501 further includes a first tank 610 and a second tank 612. The vacuum generator 620 provides vacuum suction to the first tank 610 and enables the first polishing fluid 506 to be sucked into the polishing fluid recovery module 501. Initially, the first tank 610 is filled with the first polishing fluid 506, and the second tank 612 is empty. Once the first tank 610 has been filled with the polishing fluid, the vacuum generator 620 switches to a pressure delivery mode to pressurize the first tank 610 and enables the first polishing fluid 506 to move around the polishing fluid recovery module 501 into the second tank 612 for maintaining and providing agitation of the first polishing fluid 506. The vacuum generator 620 can use a gas (i.e., nitrogen or other gas) to push the first polishing fluid 506 from the first tank 610 to the second tank 612. In another embodiment, the vacuum generator 620 can be a venturi system. The first polishing fluid 506 is continuously moved to keep the first polishing fluid 506 in a suspended state. The polishing fluid delivery from the first tank 610 to the second tank 612 distributes the fluid around the polishing fluid recovery module 501 to the second CLCSDS 504, at which point the second CLCSTS 504 may consume a portion or all of the polishing fluid and deliver the polishing fluid to the polishing system 100. Particulate matter having a particle size larger than the particle size of the polishing fluid is filtered out of the first polishing fluid 506 during the recycling process by adding a filter 615 to move the fluid from the first tank 610 to the second tank 612. Subsequently, the second polishing fluid 508 flows from the filter 615 to the second CLCSDS 504. In one embodiment, the polishing fluid recovery module 501 further includes a first purge valve 660 that is configured to be opened to enable flushing and cleaning of the fluid reuse system 500 during maintenance.

[0034] In one embodiment, Figure 6 As shown in , the fluid reuse system 500 incorporates multiple platforms, for example, a first polishing platform 630, a second polishing platform 640, and a third polishing platform 650. The fluid recovery module 501 can interact with these platforms to collect polishing fluid for one platform, all platforms, or a combination of platforms. This allows the flexibility of collecting polishing fluid only from a specific process to maximize the collection of polishing fluid from all platforms at the same time. The delivery of recycled fluid to the CLCSDS 504 can be distributed to only one platform, all platforms, or a combination of platforms.

[0035] In some embodiments, the second polishing fluid 508 collected using the fluid reuse system 500 and the first polishing fluid 506 from the polishing fluid source 126 are sequentially dispensed onto the surface of the polishing pad 104. In some embodiments, the substrate 108 is first polished using the second polishing fluid 508 collected using the fluid reuse system 500 before polishing using the first polishing fluid 506 from the polishing fluid source 126, or vice versa. In at least one embodiment, the substrate 108 is polished using only the second polishing fluid 508 collected using the fluid reuse system 500 for a first period of time before polishing using only the first polishing fluid 506 from the polishing fluid source 126 for a second period of time. Polishing the substrate 108 using only the first polishing fluid 506 from the polishing fluid source 126 for the second period of time ensures that any possible defects on the surface of the substrate 108 caused by trace contaminants or agglomerates in the second polishing fluid 508 collected using the fluid reuse system 500 are removed from the surface of the substrate 108. In some embodiments, dispensing of the second polishing fluid 508 collected using the fluid reuse system 500 is alternated with dispensing of the first polishing fluid 506 from the polishing fluid source 126. In some embodiments, the first polishing fluid 506 from the polishing fluid source 126 is mixed with the second polishing fluid collected using the fluid reuse system 500 before being delivered to the polishing surface of the polishing pad 104. Combinations of these embodiments are also within the scope of the present disclosure.

[0036] In another embodiment, the fluid reuse system 500 includes a plurality of polishing fluid recovery modules 501. This embodiment allows for a plurality of different polishing fluids to be collected independently and reused specifically at one or more stages in the process where the polishing fluids are used.

[0037] See also Figure 7, the fluid reuse system further includes a waste collection system 700. The waste collection system 700 includes a second vacuum device 705, which is disposed in the tank 202 of the sump 200 and is configured to collect waste liquid 708 from the tank 202. The waste collection system 700 further includes a waste tank 710 and a vacuum generator 720. The waste liquid 708 is drawn out of the tank 202 of the sump 200 and separated from the first polishing fluid 506 by the second vacuum device 705, which is activated to collect the fluid during the period of the flow of the rinse or cleaning fluid after or before the slurry polishing process. The vacuum force of the second vacuum device 705 is generated using the vacuum generator 720, which sucks the waste liquid 708 into the waste liquid tank 710. The waste collection system 700 then discharges the waste liquid 708 from the fluid reuse system 500 via the second drain pipe 702. In one embodiment, the waste collection system further comprises a second purge valve 740 configured to open to allow purge fluid to flow directly to the sump 200 for purge purposes.

[0038] See also Figure 8 , the polishing system 100 further includes a system controller 800 to direct its operation, including directing the operation of the fluid reuse system 500. The system controller 800 includes a programmable central processing unit, such as a CPU 802, which is operable with a memory 804 (e.g., non-volatile memory) and support circuits 806. The support circuits 806 are conventionally coupled to the CPU 802 and include caches, clock circuits, input / output subsystems, power supplies, etc., and combinations of the foregoing coupled to various components of the polishing system 100 to facilitate control of the polishing system 100. The CPU 802 is one of any form of general purpose computer processor used in an industrial environment, such as a programmable logic controller (PLC), for controlling various components and subprocessors of the polishing system 100. The memory 174 coupled to the CPU 172 is non-transitory and is typically one or more readily accessible memories such as random access memory (RAM), read only memory (ROM), a floppy disk drive, a hard disk, or any other form of digital storage, whether local or remote.

[0039] The memory 804 is in the form of a computer-readable storage medium (e.g., non-volatile memory) containing instructions that, when executed by the CPU 802, facilitate the operation of the processing system 100. The instructions in the memory 804 are in the form of a program product, such as a program that implements the methods of the present disclosure. The CPU 802 is further configured to include sensors and machine learning capabilities. The sensors of the CPU 802 are configured to measure various parameters of the fluid reuse system 500, such as pH levels, oxygen levels, and acidity levels, among other parameters. The machine learning capabilities can optimize the amount of the first polishing fluid 506 mixed with the second polishing fluid 508 to reduce the polishing cost and the amount of maintenance time required, as well as other parameters, such as pH, oxygen levels, and the possibility of acid addition for pH adjustment and control.

[0040] The memory 804 is configured to store a plurality of instructions for performing operations on the polishing system 100. For example, the memory 804 may store instructions specifying the percentage of the first polishing fluid 506 to be mixed with the second polishing fluid 508. The memory 804 may store instructions specifying the rotation speed of the platform 102 about the platform axis 112 or the substrate carrier 106 about the carrier axis 110. The memory 804 may store instructions for controlling the flow of the first and second polishing fluids 506, 508, i.e., for controlling when to change from the first polishing fluid 506 to the second polishing fluid 508, or vice versa. In addition, the memory 804 may store instructions for how the polishing process should proceed in the event that the fluid reuse system 500 is undergoing maintenance or a malfunction occurs.

[0041] The program code may conform to any of a variety of different programming languages. In one example, the present disclosure may be implemented as a program product stored on a computer-readable storage medium for use with a computer system. The program(s) of the program product define the functions of the various embodiments (including the methods described herein).

[0042] The computer-readable storage media shown include, but are not limited to: (i) non-writable storage media on which information is permanently stored (e.g., a read-only memory device within a computer, such as a CD-ROM disk readable by a CD-ROM drive, a flash memory, a read-only memory chip, or any type of solid-state non-volatile semiconductor memory); and (ii) a writable storage medium on which rewritable information is stored (e.g., a floppy disk in a disk drive or hard drive or any type of solid-state random access semiconductor memory). Such computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are embodiments of the present disclosure. In some embodiments, the methods described herein or portions thereof are performed by one or more application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other types of hardware implementations. In some other embodiments, the polishing pad manufacturing methods described herein are performed by a combination of software procedures, ASICs, FPGAs, and / or other types of hardware implementations.

[0043] See also Fig. 9 , a flow chart illustrating a method for polishing a substrate using the fluid reuse system 500 will now be briefly described. The method includes an act 901 of dispensing a first polishing fluid onto a surface of a polishing pad 104. The polishing pad 104 is disposed on a surface of a platform 102, such as a Figure 1 The platform 102 of the polishing system 100 is depicted in FIG. A first polishing fluid 506 is dispensed onto the polishing pad 104 using a fluid dispensing arm 114 positioned above the polishing pad 104 .

[0044] The method further includes act 902 of pushing substrate 108 against a surface of polishing pad 104 in the presence of first polishing fluid 506 while rotating platform 102 to remove material from the surface of substrate 108. Platform 102 is configured with polishing pad 104 disposed thereon.

[0045] The method further includes an act 903 of collecting the dispensed first polishing fluid 506 using the polishing fluid reuse system 500 described herein. When the first polishing fluid 156 leaving the dispensing unit reaches the polishing pad 104, the first polishing fluid 506 on the rotating polishing pad 104 flows toward the edge of the pad and then flows outwardly away from the platform into the groove 202 of the sump 200, as shown in FIG. Figures 1 to 3As shown in FIG. 1 , the sump 200 is disposed around at least a portion of the platform 102 . Subsequently, the vacuum device 400 collects the first polishing fluid 506 from the tank 202 and sends it to the polishing fluid recovery module 501 .

[0046] The method further includes filtering contaminants from the dispensed polishing fluid at act 904. From the trough 202 of the sump 200, the first polishing fluid 506 is directed toward one of the storage containers (i.e., the first tank 610) of the polishing fluid recovery module 501 (using a valve fluidly coupled therebetween). The inlet of the valve is further fluidly coupled to the suction pipe 402 of the vacuum device 400. Once the first tank 610 is filled with polishing fluid, the suction valve is closed, and the vacuum generator 620 is configured to pressurize the first tank 610 and move the fluid through a recirculation loop containing a filter 615 to polish the first polishing fluid 506 into a second polishing fluid 508.

[0047] The method further includes act 905 of dispensing a second polishing fluid 508 to the polishing system 100. In some embodiments, the second polishing fluid 508 collected using the fluid reuse system 500 and the first polishing fluid 506 from the polishing fluid source 126 are dispensed sequentially onto the surface of the polishing pad 104. For example, in some embodiments, the substrate 108 is first polished using the second polishing fluid 508 collected using the fluid reuse system 500 before polishing using the first polishing fluid 506 from the polishing fluid source 126, or vice versa. For example, in at least one embodiment, the substrate 108 is polished using only the second polishing fluid 508 collected using the fluid reuse system 500 for a first period of time before polishing using only the first polishing fluid 506 from the polishing fluid source 126 for a second period of time. Polishing the substrate 108 using only the first polishing fluid 506 from the polishing fluid source 126 for the second period of time ensures that any possible defects on the surface of the substrate 108 caused by trace contaminants or agglomerates in the second polishing fluid 508 collected using the fluid reuse system 500 are removed from the surface of the substrate 108. In some embodiments, dispensing of the second polishing fluid 508 collected using the fluid reuse system 500 alternates with dispensing of the first polishing fluid 506 from the polishing fluid source 126. In some embodiments, the first polishing fluid 506 from the polishing fluid source 126 is mixed with the second polishing fluid collected using the fluid reuse system 500 before being delivered to the polishing surface of the polishing pad 104.

[0048] Advantageously, the systems and methods provided herein facilitate the collection and reuse of expensive CMP polishing fluids without the need for substantial reprocessing thereof.

[0049] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope of the disclosure and the scope of the disclosure is determined by the claims that follow.

Claims

1. A polishing system comprising: A water collection tank sized to surround and abut a polishing pad secured to a platform, the water collection tank comprising: Inner wall; an outer wall disposed radially outward from the inner wall; and a base connecting the inner wall to the outer wall, the base being configured to couple the water collection tank to the platform so that the water collection tank rotates together with the platform and the polishing pad, wherein: The outer wall, the inner wall and the base collectively define a slot; as well as the radially inwardly facing surface of the sump being further defined by an arcuate radius equal to the arcuate radius of the platform about which the sump is sized, the radially inwardly facing surface of the sump being configured to allow polishing fluid to flow radially outwardly from the polishing pad into the grooves; a first vacuum device, the first vacuum device comprising a suction tube; wherein the suction tube is disposed within the slot of the sump, wherein the suction tube is fixed relative to the sump when rotating; and A polishing fluid recovery module, wherein the first vacuum device sucks the polishing fluid out of the tank and sends the polishing fluid to the polishing fluid recovery module for reuse.

2. The polishing system of claim 1, wherein the suction tube is sized to be spaced apart from the base of the sump by a gap of up to 5 mm.

3. The polishing system of claim 1, wherein the outer wall, the inner wall, and the base comprise a hydrophobic material. The polishing system of claim 3 , wherein the hydrophobic material is a polymer material.

5. The polishing system of claim 1, wherein the top of the inner wall comprises a sloped edge on a groove-facing surface of the inner wall.

6. The polishing system of claim 1, wherein the base comprises a plurality of holes configured to receive fasteners, wherein the fasteners couple the sump to the platform such that the sump rotates with the platform and the polishing pad.

7. The polishing system of claim 1, further comprising a second vacuum device spaced apart from the first vacuum device along the slot, wherein the first vacuum device is configured to collect polishing fluid, and wherein the second vacuum device is configured to collect waste fluid.

8. A fluid recycling system, the system comprising: platform; a polishing pad fixed to the platform; first and second closed-loop controlled slurry delivery systems (CLCSDS), wherein the first CLCSDS delivers a first polishing fluid to the polishing pad, wherein the first polishing fluid is collected by a sump, the sump comprising: Inner wall; an outer wall disposed radially outward from the inner wall; and a base connecting the inner wall to the outer wall, the base being configured to couple the sump to the platform so that the sump rotates with the platform, wherein: The outer wall, the inner wall and the base collectively define a slot; and The radially inwardly facing surface of the sump is defined by an arcuate radius equal to the radius of the platform that the sump is sized to surround; and a first vacuum device, the first vacuum device comprising a suction tube, wherein the suction tube is disposed within the groove of the sump and is spaced from the base, and wherein the suction tube is fixed relative to the sump when rotating; wherein the first vacuum device collects the first polishing fluid; a polishing fluid recovery module configured to recover the first polishing fluid into a second polishing fluid, wherein the second polishing fluid is provided to the second CLCSDS; and The second CLCSDS delivers the second polishing fluid to the platform, and the first CLCSDS delivers the first polishing fluid to the platform, to allow a polishing process to be configured to operate from the first polishing fluid, from the second polishing fluid, or from a mixture of the two.

9. The fluid reuse system of claim 8, further comprising a controller comprising a CPU, a memory, and a plurality of support circuits, the controller being configured to control the flow of the first polishing fluid and the second polishing fluid.

10. The fluid reuse system of claim 9, wherein the controller further comprises a sensor for monitoring the fluid reuse system and fluid properties of the first polishing fluid and the second polishing fluid.

11. The fluid reuse system of claim 10, wherein the fluid property is one of the following: pH value, dissolved oxygen, or both.

12. The fluid recycling system of claim 10, wherein the controller further comprises an amount of acid added to change the pH value of the first polishing fluid and the second polishing fluid.

13. The fluid reuse system of claim 10, wherein the memory contains instructions for controlling flow of the first polishing fluid and the second polishing fluid through the fluid reuse system.

14. The fluid reuse system of claim 13, wherein the controller further comprises machine learning capabilities.

15. The fluid reuse system of claim 8, wherein the fluid reuse system further comprises a second vacuum device, wherein the first vacuum device collects the first polishing fluid and the second vacuum device is configured to collect waste fluid.

16. The fluid recycling system of claim 15, wherein the fluid recycling system further comprises a waste collection system that separates the waste liquid collected by the second vacuum device from the first polishing fluid in the sump and discharges the waste liquid from the fluid recycling system.

17. The fluid reuse system of claim 8, further comprising a plurality of polishing fluid recovery modules.

18. A method for polishing a substrate, comprising the steps of: dispensing a polishing fluid onto a surface of the polishing pad; pushing the substrate against the surface of the polishing pad while rotating a platform, the platform having the polishing pad disposed thereon; The polishing fluid is collected using a fluid recycling system, wherein: The fluid reuse system includes a sump coupled to the platform, the sump being configured to abut the platform and rotate with the platform; and at least some of the polishing fluid dispensed onto the polishing pad is collected in a trough of the sump; collecting the polishing fluid by a vacuum device, the vacuum device comprising a suction tube disposed within the tank; filtering contaminants from the polishing fluid; and The polishing fluid collected using the sump is distributed onto the surface of the polishing pad.

19. The method of claim 18, wherein the sump comprises an outer wall, an inner wall disposed radially inward from the outer wall, and a base connecting the inner wall to the outer wall, wherein the outer wall, the inner wall and the base collectively define a trough.

20. The method of claim 19 wherein the suction tube is disposed within the trough in spaced relation to the base of the sump.

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