Polishing fluid recovery and reuse system for semiconductor substrate processing

Abstract

A polishing system (100), a fluid recycling system (500), and a method for polishing a substrate. The polishing system includes a catch basin (200), a pressure reduction device (400), and a polishing fluid recycling module (501) for recycling polishing fluid. The catch basin is sized to surround and abut a polishing pad (104) secured to a platen (102). The radially inward-facing surface of the catch basin is further defined by an arc radius equal to the arc radius of the platen around which the catch basin is sized. The radially inward-facing surface of the catch basin is configured to allow polishing fluid to flow radially outward from the polishing pad into a trough. The system and method collect and reuse polishing fluid used during a chemical mechanical polishing (CMP) process for manufacturing electronic devices.

Description

[Technical Field]

[0001]

[0001] The embodiments described herein relate generally to systems and methods used to process semiconductor substrates in electronic device manufacturing processes, and more particularly to a system for collecting and reusing polishing fluids used in chemical mechanical polishing (CMP) of semiconductor substrates, and a substrate processing method associated with the system. [Background technology]

[0002]

[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 involves contacting the material layer of the substrate to be planarized with a polishing pad and moving the polishing pad, the substrate, or both in the presence of a polishing fluid, thus creating relative motion between the material layer surface and the polishing pad. Material is removed throughout the material layer surface in contact with the polishing pad by a combination of chemical and mechanical action, at least partially provided by the polishing fluid. Commonly used polishing fluids include abrasive particle-containing slurries, such as colloids or suspensions, reactive liquid (abrasive-free) slurries, and abrasive-free or reduced-abrasive polishing fluids, used in conjunction with a fixed-abrasive polishing pad with abrasive particles disposed therein.

[0003]

[0003] Polishing fluids are typically highly engineered to provide desired chemical and mechanical polishing performance characteristics and to disperse and maintain abrasive particles in a colloid or relatively stable suspension. Due at least in part to the high cost of designing and manufacturing CMP polishing fluids, the CMP process is often the most expensive substrate processing step in the manufacture of semiconductor devices.

[0004]

[0004] Therefore, there is a need in the art for methods and systems for collecting and reusing polishing fluids used in semiconductor processing processes to reduce the costs associated with polishing fluids used in semiconductor device manufacturing. Summary of the Invention

[0005] SUMMARY

[0005] The present disclosure generally relates to methods and systems used to collect and reuse polishing fluids used during chemical mechanical polishing (CMP) processes for the manufacture of electronic devices.

[0006] In one embodiment, a polishing system is disclosed. The polishing system includes a catch basin sized to surround and abut a polishing pad secured to a platen. The catch basin includes an inner wall, an outer wall disposed radially outward from the inner wall, and a base portion connecting the inner wall to the outer wall. The base portion is configured to couple the catch basin to the platen, thereby causing the catch basin to rotate with the platen and polishing pad. The outer wall, inner wall, and base portion collectively define a trough. The radially inward-facing surface of the catch basin is further defined by an arc radius equal to the arc radius of the platen, about which the catch basin is sized to surround the platen. The inward-facing surface of the catch basin is configured to allow polishing fluid to flow radially outward from the polishing pad into the trough. The polishing system further includes a vacuum device, the vacuum device comprising a suction tube. The suction tube is disposed within the trough of the catch basin and spaced from the base portion. The suction tube is stationary relative to the rotating catch basin. The polishing system further includes a polishing fluid recycling module. The suction tube draws the polishing fluid from the trough and delivers the polishing fluid to the polishing fluid recycling module for reuse.

[0007] In another embodiment, a fluid recycling system is disclosed. The system includes a platen, a polishing pad secured to the platen, and first and second closed-loop controlled slurry supply systems (CLCSDS). The first CLCSDS supplies a first polishing fluid to the polishing pad, where the first polishing fluid is collected by a polishing-fluid catch basin. The polishing-fluid catch basin includes an inner wall, an outer wall disposed radially outward from the inner wall, and a base portion connecting the inner wall to the outer wall. The base portion is configured to couple the catch basin to the platen, thereby causing the catch basin to rotate with the platen. The outer wall, inner wall, and base portion collectively define a trough. A radially inward-facing surface of the catch basin is defined by an arc radius equal to the radius of the platen, with the catch basin sized to surround the platen. The fluid recycling system further includes a vacuum device, the vacuum device comprising a suction tube. The suction tube is disposed within the trough of the catch basin and is spaced apart from the base portion. The suction tube is stationary relative to the rotating catch basin, allowing the pressure reducing device to collect the first polishing fluid. The fluid reuse system further includes a polishing fluid recycle system module. The polishing fluid recycle module is configured to recycle the first polishing fluid into a second polishing fluid. The second polishing fluid is provided to the second CLCSDS. The second CLCSDS supplies the second polishing fluid to the polishing pad. The first polishing fluid may be simultaneously supplied to the polishing pad by the first CLCSDS so that a mixture of the first and second polishing fluids can be used. Alternatively, the flow of the first polishing fluid may be stopped, and only the second polishing fluid may be supplied to the polishing pad.

[0008] In another embodiment, a method for polishing a substrate is disclosed. The method includes dispensing a polishing fluid onto a surface of a polishing pad, pressing a substrate against the surface of the polishing pad while rotating a platen, the platen having a polishing pad disposed thereon, collecting the polishing fluid using a fluid recycling system, filtering the polishing fluid to remove contaminants, and dispensing the collected polishing fluid onto the polishing pad using a polishing-fluid catch basin. The fluid recycling system includes a catch basin coupled to the platen. The catch basin is configured to abut against the platen and rotate with the platen. At least a portion of the polishing fluid dispensed onto the polishing pad is collected in a trough of the catch basin. The polishing fluid is collected by a vacuum device, the vacuum device including a suction tube disposed in the trough.

[0009]

[0009] For ease of understanding, wherever possible, identical reference numerals have been used to designate identical elements common to the figures. It is believed that elements and features of one embodiment may be beneficially incorporated in multiple other embodiments without further description.

[0010]

[0010] So that the above features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above can be made by reference to 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 the present disclosure may admit of other equally effective embodiments, and therefore the accompanying drawings should not be considered as limiting the scope of the present disclosure. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic side view of a polishing system configured with a catch basin (shown in cross section) according to several embodiments. [Figure 2]

[0012] FIG. 2 is a schematic perspective view of a portion of the catch basin shown in FIG. 1, according to several embodiments. [Figure 3]

[0013] FIG. 1 is a schematic side view of a catch basin (shown in cross section), according to several embodiments. [Figure 4A]

[0014] 1 is a schematic perspective view of a reduced pressure device, according to several embodiments. [Figure 4B]

[0015] 1 is a schematic side view of a reduced pressure device, according to several embodiments. [Figure 5A]

[0016] 1 is a schematic diagram of a fluid recycling system, according to several embodiments. [Figure 5B] 1 is a schematic diagram of a fluid recycling system, according to several embodiments. [Figure 6]

[0017] FIG. 2 is a schematic diagram of a polishing fluid recycle module of a fluid reuse system, according to several embodiments. [Figure 7]

[0018] FIG. 7 is a schematic diagram of a wastewater collection system that can be used with the fluid catch basin shown in FIGS. 1-6, according to several embodiments. [Figure 8]

[0019] FIG. 1 is a schematic diagram of a controller unit configured to control a fluid reuse system and a wastewater collection system, according to several embodiments. [Figure 9]

[0020] FIG. 1 is a flow diagram of a method for utilizing a fluid recycling system, according to several embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0012]

[0021] For ease of understanding, the same reference numerals have been used, where possible, to designate identical elements common to the figures, and it is contemplated that elements and features of each embodiment may be beneficially incorporated in multiple other embodiments without further recitation.

[0013]

[0022]

[0003] Embodiments of the present disclosure generally provide systems for collecting and reusing polishing fluids, and related methods. In particular, the systems and methods provided herein feature a polishing fluid collection system used to collect and recycle polishing fluids dispensed during chemical mechanical polishing (CMP) of substrates in an electronic device manufacturing process.

[0014]

[0023] In a conventional CMP process, a polishing fluid is dispensed onto the surface of a polishing pad attached to a rotating platen. The polishing fluid is dispensed onto the surface of the polishing pad, and a substrate is pressed against the polishing pad in the presence of the polishing fluid. The dispensed polishing fluid is distributed radially outward from the dispense location by centrifugal force imparted to the polishing fluid from the rotation of the platen. Upon reaching the periphery of the polishing pad, the polishing fluid typically flows into a drainage channel. The drainage channel surrounds the platen and extends into an area disposed below the platen. This facilitates the capture of fluids and other processing by-products used during the CMP substrate process and other processing activities (e.g., pad cleaning and pad conditioning activities), as well as all associated polishing by-products. Often, the volume of non-abrasive fluids far exceeds the volume of the polishing fluid, e.g., by five times or more. Therefore, wastewater from the drainage channel typically contains highly diluted and contaminated polishing fluid. Accordingly, embodiments herein provide an abrasive fluid capture system to capture the abrasive fluid before the fluid would otherwise flow into the drain, thus avoiding any contamination and dilution of the fluid.

[0015]

[0024] Efforts to recycle polishing fluids have been largely unsuccessful, due at least in part to the relatively low concentration of polishing fluids in the wastewater in the drains and variations in the wastewater composition. Additionally, polishing processes often use two or more polishing fluids, each of which is sequentially supplied to the polishing pad at different stages in 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 wastewater treatment and recycling process. Beneficially, embodiments provided herein are configured to selectively capture used polishing fluids closer to the polishing process, i.e., before the used polishing fluid flows into the drains, and reuse the captured polishing fluid without the need for additional expensive processing. Therefore, embodiments provided herein can be used to substantially reduce the cost per substrate polished during a semiconductor device manufacturing process.

[0016]

[0025] In one aspect, the polishing system herein includes a catch basin disposed adjacent to a rotatable platen. The catch basin surrounds the platen, is sized to abut the platen, and is configured to be coupled to the platen so that the catch basin rotates with the platen. A pressure reducing device is disposed within the trough of the catch basin and is stationary relative to the rotating catch basin. The pressure reducing device is used to draw polishing fluid from the trough of the catch basin and into a polishing fluid recycling module for recycling the polishing fluid.

[0017]

[0026] 1 is a schematic side view of a polishing system 100, according to one embodiment. Herein, the polishing system 100 includes a cylindrical platen 102, a polishing pad 104 secured to the platen (e.g., by using a pressure-sensitive adhesive), a substrate carrier 106 positioned above the platen 102 opposite the polishing pad 104, and a catch basin 200 used to collect and recycle polishing fluid from the polishing process. During a typical process, the substrate carrier 106 presses a material surface of a substrate 108 disposed within the substrate carrier 106 against the polishing pad 104 while simultaneously rotating about a carrier axis 110. To partially reduce uneven wear on the polishing pad 104, the platen 102 rotates about a platen axis 112 while the rotating substrate carrier 106 sweeps back and forth from the inner diameter to the outer diameter of the platen 102. In some embodiments, the polishing system 100 further includes a pad conditioner assembly (not shown) that is used to polish, rejuvenate, and remove by-products or debris from the surface of the polishing pad 104.

[0018]

[0027] As shown, polishing fluid, abrasive agent of the polishing fluid, cleaning fluid, and / or deionized (DI) water are supplied from a polishing fluid source 126 to a fluid dispensing arm 114 disposed above the platen 102 and dispensed onto the polishing pad 104 using a nozzle 116 disposed within the fluid dispensing arm 114. The fluid dispensing arm 114 is coupled to an actuator 118. The actuator 118 positions the fluid dispensing arm 114 above the platen 102 by swinging the fluid dispensing arm 114 above the platen 102. The actuator 118 is disposed on a base plate 120 that surrounds the platen 102. As described further below, a system controller 800 controls the actuator, the amount of polishing fluid dispensed by the fluid dispensing arm 114, and a fluid recycling system 500 (described below).

[0019]

[0028] 2 and 3, the catch basin 200 (shown in cross section in FIG. 1) is sized to surround and abut the polishing pad 104. The catch basin 200 includes an inner wall 210, an outer wall 212, and a base portion 214. The outer wall 212 is disposed radially outward from the inner wall 210. The base portion 214 connects the inner wall 210 to the outer wall 212. The inner wall 210, the outer wall 212, and the base portion 214 collectively define a trough 202. Although the trough 202 is shown in FIG. 1 as having a U-shaped profile in cross section, any suitable cross-sectional shape may be used. The components of the catch basin 200, i.e., the inner wall 210, the outer wall 212, and the base portion 214, are formed of an abrasive fluid chemically resistant polymer having a hydrophobic surface. Examples of suitable polymers include fluorine-containing polymers (fluoropolymers), such as perfluoroalkoxy (FA), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), commercially available from DuPont as TEFLON®, or combinations thereof. In some embodiments, the base portion 214 of the catch basin 200 is an annular ring that surrounds and is fixedly coupled to the platen 102. The base portion 214 is configured with a plurality of holes 222 configured to receive a plurality of fasteners 220. The fasteners couple the catch basin 200 to the platen 102 so that the catch basin 200 rotates about the platen axis 112 together with the polishing pad 104.

[0020]

[0029] The catch basin 200 collects the polishing fluid that spins radially outward from the rotating polishing pad 104 due to centrifugal forces imparted to the polishing fluid. In one embodiment, the catch basin is approximately 2 feet in diameter. The outer wall 212 is spaced from the inner wall 210 by the width W(1) of the trough 202. The width W(1) is between about 0.5 cm and about 5 cm. The combined width W(2) of the trough 202 and the thickness of 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) in the Z direction from the base portion 214, although different heights may be used for each of the walls. The radially inward-facing surface 230 of the catch basin 200 is further defined by an arc radius equal to the arc radius of the polishing pad 104, such that the catch basin 200 is sized to surround the polishing pad 104. This allows all of the polishing fluid flowing radially outward from the surface of the polishing pad 104 to enter the trough 202 and not fall between the catch basin 200 and the polishing pad 104 .

[0021]

[0030] Referring to FIG. 4 , the catch basin 200 further includes a pressure reduction device 400. The pressure reduction device 400 includes a suction tube 402. The catch basin 200 does not include a gravity drain or opening that can be used to drain the polishing fluid from the trough 202. The collection efficiency of a gravity drainage system is poor because the liquid is dispersed over a large surface area, resulting in slow drainage. The suction tube 402 is disposed within the trough 202 of the catch basin 200. The suction tube 402 is spaced from the base portion 214 to avoid wear on the suction tube 402 while still allowing sufficient suction. Thus, the polishing fluid is extracted from the trough 202 through the use of the suction tube 402. While the pressure reduction device 400 is configured to be stationary relative to the rotating catch basin 200, it is envisioned that it may have the ability to control its movement with an actuation device to optimize fluid collection or remove the collection tube for maintenance. The pressure-reducing device 400 is supported by a portion of the polishing system 100 that does not rotate with the platen 102, such as by use of a bracket 410. The pressure-reducing device 400 draws polishing fluid from the trough 202 as the polishing fluid flows from the polishing pad 104 into the trough 202.

[0022]

[0031] In some embodiments, the catch basin 200 is coupled to a Z actuator. The Z actuator is configured to raise and lower the catch basin 200 in the Z direction. In these embodiments, the radially inward-facing surface 230 of the catch basin 200 is defined by an arc radius that is larger than the arc radius of the polishing pad 104, around which the catch basin 200 is sized. The inner wall 210 is further configured to include a lip 240 that spans the gap between the arc radius of the radially inward-facing surface 230 of the catch basin 200 and the arc radius of the polishing pad 104. In these embodiments, the catch basin 200 is raised when unwanted fluid is dispensed onto the polishing pad 104 for reuse. In the raised position, the radially inward-facing surface 230 and the lip 240 prevent fluid flowing from the edge of the polishing pad from entering the trough 202 of the catch basin 200. Thus, fluids not desired for reuse flow through the gap defined by the radially inward-facing surface 230 of the catch basin 200 and the arc radius of the polishing pad 104 and into the drain groove 122 (shown in FIG. 1 ) located below the catch basin 200. When polishing fluid desired for reuse has been dispensed onto the polishing pad 104, the catch basin 200 is lowered to a fluid collection position, and the polishing fluid desired for reuse is collected using the methods described herein.

[0023]

[0032] Referring to FIG. 5, a fluid reuse system 500 is shown. The fluid reuse system 500 includes a polishing fluid recycle module 501 and one or more polishing systems 100. The fluid reuse system 500 further includes a first closed-loop controlled slurry supply system (CLCSDS) 502 and a second CLCSDS 504. The first CLCSDS 502 supplies a first polishing fluid 506 from a polishing fluid source 126 through a fluid discharge arm 114 to a polishing pad 104 of one of the polishing systems 100. The polishing fluid source 126 comprises a centralized or localized fluid distribution system used by a manufacturing facility to supply 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 process. The first polishing fluid 506 is then collected by a catch basin 200 and drawn from the catch basin 200 by a pressure reduction device 400. The polishing fluid recycle module 501 collects the first polishing fluid 506 extracted from the trough 202 of the catch basin 200 through the pressure reducing device 400 and recycles / filters the first polishing fluid 506 to produce a second polishing fluid 508. The second polishing fluid 508 is then provided to the second CLCSDS 504 for delivery to the platen 102. The first polishing fluid 506 can be stopped by the first CLCSDS 502 when the second polishing fluid 508 has been delivered to the platen 102, thereby allowing the system 500 to operate continuously using the second polishing fluid 508. Alternatively, the flow rates of the first polishing fluid 506 and 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 platen 102. This allows the first polishing fluid 506 to compensate for any losses in the collection process and enables a preferential process for adjusting the mixing ratio of the first polishing fluid 506 and the second polishing fluid 508 for optimal polishing of the substrate 108. In another embodiment, as shown in FIG. 5B , the system 500 includes a static mixer 560 for pre-mixing the first polishing fluid 506 and the second polishing fluid 508 before delivering the polishing fluids to the platen 102.

[0024]

[0033] 6 , the polishing fluid recycle module 501 further includes a first tank 610 and a second tank 612. A vacuum generator 620 provides vacuum suction to the first tank 610, allowing the first polishing fluid 506 to be sucked into the polishing fluid recycle module 501. Initially, the first tank 610 is filled with the first polishing fluid 506, while the second tank 612 is empty. Once the first tank 610 is filled with the polishing fluid, the vacuum generator 620 pressurizes the first tank 610, allowing the first polishing fluid 506 to move and retain in the second tank 612 around the polishing fluid recycle module 501, and switches to a pressure supply mode to provide agitation to the first polishing fluid 506. The reduced pressure generator 620 may utilize 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 reduced pressure generator 620 may be a Venturi system. The first polishing fluid 506 is in continuous motion to maintain the first polishing fluid 506 in suspension. The transfer of the polishing fluid from the first tank 610 to the second tank 612 discharges the fluid around the polishing fluid recycle module 501 to the second CLCSDS 504. At this point, the second CLCSDS 504 may consume some or all of the polishing fluid and supply the polishing fluid to the polishing system 100. During the recirculation process to move the fluid from the first tank 610 to the second tank 612, the addition of a filter 615 filters out particulate matter having a particle size larger than that of the polishing fluid from the first polishing fluid 506. The second polishing fluid 508 then flows from the filter 615 to the second CLCSDS 504. In one embodiment, the polishing fluid recycle module 501 further comprises a first clean valve 660. The first clean valve 660 is configured to open to allow flushing and cleaning of the fluid reuse system 500 during maintenance.

[0025]

[0034] In one embodiment, as shown in FIG. 6 , a fluid reuse system 500 incorporates multiple platens, e.g., a first polishing platen 630, a second polishing platen 640, and a third polishing platen 650. The fluid recycle module 501 can interact with these platens to collect polishing fluid for one platen, all platens, or a combination thereof. This allows flexibility to collect polishing fluid from only specific processes, while maximizing the collection of polishing fluid from all platens simultaneously. The recirculated fluid supply to the second CLCSDS 504 can be distributed to only one platen, all platens, or a combination thereof.

[0026]

[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 being polished 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 being polished using only the first polishing fluid 506 from the polishing fluid source 126 for a second period of time. Polishing the substrate 108 with only the first polishing fluid 506 from the polishing fluid source 126 for the second period of time ensures that any potential 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, the discharge of the second polishing fluid 508 collected using the fluid reuse system 500 is alternated with the discharge 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.

[0027]

[0036] In another embodiment, fluid reuse system 500 includes multiple polishing fluid recycle modules 501. This embodiment allows multiple different polishing fluids to be collected independently and reused specifically for one or more platens used in the process.

[0028]

[0037] Referring to FIG. 7 , the fluid reuse system further includes a wastewater collection system 700. The wastewater collection system 700 includes a second pressure reduction device 705 disposed within the trough 202 of the catch basin 200 and configured to collect waste fluid 708 from the trough 202. The wastewater collection system 700 further includes a wastewater tank 710 and a vacuum generator 720. The waste fluid 708 is drawn from the trough 202 of the catch basin 200 and separated from the first polishing fluid 506 by the second pressure reduction device 705. The second pressure reduction device 705 is activated to collect fluid during periods when a rinsing or cleaning fluid is flowing before and after the slurry polishing process. The vacuum pressure of the second pressure reduction device 705 is generated using the vacuum generator 720. The vacuum generator 720 draws the waste fluid 708 into the wastewater tank 710. The wastewater collection system 700 then discharges the waste fluid 708 from the fluid reuse system 500 through a second outlet 702. In one embodiment, the wastewater collection system further comprises a second clean valve 740. The second clean valve 740 is configured to open to allow the flow of cleaning fluid directly into the catch basin 200 for cleaning purposes.

[0029]

[0038] 8 , the polishing system 100 further includes a controller 800 that directs the operation of the polishing system 100, including directing the operation of the fluid reuse system 500. The system controller 800 includes a programmable processing unit, such as a CPU 802. The CPU 802 is operable with a memory 804 (e.g., non-volatile memory) and support circuits 806. The support circuits 806 are conventionally connected to the CPU 802 and include cache, clock circuits, input / output subsystems, power supplies, etc., and combinations thereof, coupled to various components of the polishing system 100 to facilitate control of the various components of the polishing system 100. The CPU 802 is one of any form of general-purpose computer processor used in industrial settings, such as a programmable logic controller (PLC), for controlling the various components and sub-processors of the processing system 100. The memory 804 connected to the CPU 802 is non-transitory and typically comprises one or more readily available memories (e.g., random access memory (RAM), read only memory (ROM), a floppy disk drive, a hard disk, or any other form of local or remote digital storage).

[0030]

[0039] The memory 804 may take the form of a computer-readable storage medium (e.g., non-volatile memory) containing instructions that, when executed by the CPU 802, facilitate operation of the polishing system 100. The instructions in the memory 804 may take 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 level, oxygen level, and acidity level, among others. The machine learning capabilities can optimize the amount of the first polishing fluid 506 mixed with the second polishing fluid 508 to reduce polishing costs and required maintenance time, as well as other parameters such as pH, oxygen level, and the possibility of adding acid for pH adjustment and control.

[0031]

[0040] The memory 804 is configured to store instructions for performing operations in the polishing system 100. For example, the memory 804 may hold instructions specifying the percentage of the first polishing fluid 506 to be mixed with the second polishing fluid 508. The memory 804 may hold instructions specifying the rotational speed of the platen 102 about the platen axis 112 and the substrate carrier 106 about the carrier axis 110. The memory 804 may hold instructions for controlling the flow rates of the first and second polishing fluids 506, 508, i.e., when changing from the first polishing fluid 506 to the second polishing fluid 508 or vice versa. Additionally, the memory 804 may hold instructions on how to proceed with the polishing process in the event that the fluid reuse system 500 is undergoing maintenance or has failed.

[0032]

[0041] The program code may conform to any one of a number 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) in the program product define functions of the embodiments (including the methods described herein).

[0033]

[0042] Exemplary computer-readable storage media include, but are not limited to, (i) non-writable storage media on which information is permanently stored (e.g., a read-only memory device internal to a computer, such as a CD-ROM disk readable in a CD-ROM drive, a flash memory, a ROM chip, or any type of solid-state non-volatile semiconductor memory), and (ii) writable storage media on which changeable information is stored (e.g., a floppy disk or hard disk drive in a diskette 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, constitute 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 routines, ASICs, FPGAs, and / or other types of hardware implementations.

[0034]

[0043] 9, a flow diagram illustrating a method for polishing a substrate using the fluid recycling system 500 will now be briefly described. The method includes a step 901 of dispensing a first polishing fluid onto the surface of the polishing pad 104. The polishing pad 104 is disposed on the surface of a platen 102, such as the platen 102 of the polishing system 100 illustrated in FIG. 1. A first polishing fluid 506 is dispensed onto the polishing pad 104 using a fluid dispensing arm 114 positioned above the polishing pad 104.

[0035]

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

[0036]

[0045] The method further includes step 903 of collecting the dispensed first polishing fluid 506 using the polishing fluid reuse system 500 described herein. When the first polishing fluid 156 exiting 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 into the trough 202 of the catch basin 200 (as illustrated in FIGS. 1-3 ) outwardly away from the platen 102. The catch basin 200 is disposed around at least a portion of the platen 102. A pressure reducing device 400 then collects the first polishing fluid 506 from the trough 202 and sends it to the polishing fluid recycle module 501.

[0037]

[0046] The method further includes step 904 of filtering the discharged polishing fluid to remove contaminants. A first polishing fluid 506 is directed from the trough 202 of the catch basin 200 toward one of the storage vessels (i.e., first tank 610) of the polishing fluid recycle module 501 using a valve fluidically coupled therebetween. An inlet to the valve is further fluidically coupled to the suction pipe 402 of the pressure reduction device 400. Once the first tank 610 is filled with polishing fluid, the suction valve is closed and a pressure reduction generator 620 pressurizes the first tank 610, moving the fluid through a recirculation loop including a filter 615 to refine the first polishing fluid 506 into a second polishing fluid 508.

[0038]

[0047] The method further includes step 905 of dispensing a second polishing fluid 508 into 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 sequentially dispensed 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 being polished 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 being polished using only the first polishing fluid 506 from the polishing fluid source 126 for a second period of time. Polishing the substrate 108 with only the first polishing fluid 506 from the polishing fluid source 126 for the second period of time ensures that any potential 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, the ejection of the second polishing fluid 508 collected using the fluid reuse system 500 is alternated with the ejection 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.

[0039]

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

[0040]

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

Claims

1. 1. A polishing system comprising: a catch basin sized to surround and abut a polishing pad secured to a platen, the catch basin comprising: inner wall, an outer wall disposed radially outward from the inner wall; and a base portion connecting the inner wall to the outer wall, the base portion configured to couple the catch basin to the platen such that the catch basin rotates with the platen and the polishing pad; the outer wall, the inner wall, and the base portion collectively define a trough; a radially inwardly facing surface of the catch basin further defined by an arc radius equal to an arc radius of the platen about which the catch basin is sized to surround the platen, the radially inwardly facing surface of the catch basin configured to allow polishing fluid to flow radially outward from the polishing pad into the trough; The polishing system further comprises: a first pressure reduction device including a suction tube disposed within the trough of the catch basin, the suction tube being stationary relative to the catch basin as the catch basin rotates; and A polishing system comprising a polishing fluid recycle module, wherein the first pressure reducing device draws polishing fluid from the trough and delivers the polishing fluid to the polishing fluid recycle module for reuse.

2. 10. The polishing system of claim 1, wherein the suction tube is sized to be spaced from the base portion of the catch basin 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 portion comprise a hydrophobic material.

4. The polishing system of claim 3 , wherein the hydrophobic material is a polymeric material.

5. The polishing system of claim 1 , wherein the upper portion of the inner wall includes a chamfered edge on a trough facing the surface of the inner wall.

6. 2. The polishing system of claim 1, wherein the base portion includes a plurality of holes configured to receive fasteners, the fasteners coupling the catch basin to the platen such that the catch basin rotates with the platen and the polishing pad.

7. 2. The polishing system of claim 1, further comprising a second pressure-reducing device spaced apart from the first pressure-reducing device along the trough, the first pressure-reducing device configured to collect polishing fluid and the second pressure-reducing device configured to collect waste fluid.

8. 1. A fluid recycling system comprising: Platen, a polishing pad fixed to the platen; a first closed loop controlled slurry supply system (CLCSDS) and a second CLCSDS, the first CLCSDS supplying a first polishing fluid to the polishing pad, the first polishing fluid being collected by a catch basin, the catch basin comprising: inner wall, an outer wall disposed radially outward from the inner wall; and a base portion connecting the inner wall to the outer wall, the base portion configured to couple the catch basin to the platen such that the catch basin rotates with the platen; the outer wall, the inner wall, and the base portion collectively define a trough; a first CLCSDS and a second CLCSDS, the radially inward facing surface of the catch basin being defined by an arc radius equal to the radius of the platen about which the catch basin is sized to surround the platen; a first pressure reduction device including a suction tube disposed within the trough of the catch basin and spaced apart from the base portion, the suction tube being stationary relative to the catch basin as the catch basin rotates, the first pressure reduction device collecting the first polishing fluid; and a polishing fluid recycling module configured to recycle the first polishing fluid into a second polishing fluid, the second polishing fluid being provided to the second CLCSDS; A fluid reuse system, wherein the second CLCSDS supplies the second polishing fluid to the platen and the first CLCSDS supplies the first polishing fluid to the platen, allowing a polishing process to be configured to function from the first polishing fluid, from the second polishing fluid, or from a mixture of both.

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

10. 10. The fluid reuse system of claim 9, wherein the controller further comprises sensors 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 pH and dissolved oxygen, or both.

12. The fluid reuse system of claim 11 , wherein the controller further comprises adding an amount of acid necessary to modify the pH of the first polishing fluid and the second polishing fluid.

13. The fluid reuse system of claim 10 , wherein the memory includes a plurality of instructions for controlling the flow rates 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. 9. The fluid reuse system of claim 8, further comprising a second pressure reducing device, wherein the first pressure reducing device is configured to collect the first polishing fluid and the second pressure reducing device is configured to collect waste fluid.

16. 16. The fluid reuse system of claim 15, further comprising a wastewater collection system that separates the waste fluid collected by the second pressure reduction device from the first polishing fluid in the catch basin and discharges the waste fluid from the fluid reuse system.

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

18. 1. A method of polishing a substrate, comprising: Discharging a polishing fluid onto the surface of the polishing pad; pressing the substrate against the surface of the polishing pad while rotating a platen, the platen having the polishing pad disposed thereon; collecting said polishing fluid using a fluid recycling system, the fluid recycling system includes a catch basin coupled to the platen, the catch basin configured to abut against the platen and rotate with the platen; At least a portion of the polishing fluid dispensed onto the polishing pad is collected in a trough of the catch basin; collecting the polishing fluid by a vacuum device, the vacuum device comprising a suction tube disposed within the trough; filtering the polishing fluid to remove contaminants; and discharging the polishing fluid collected using the catch basin onto the surface of the polishing pad.

19. 20. The method of claim 18, wherein the catch basin comprises an outer wall, an inner wall disposed radially inward of the outer wall, and a base portion connecting the inner wall to the outer wall, the inner wall, the outer wall, and the base portion collectively defining the trough.

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

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