US20250010431A1

US20250010431A1 - Polishing fluid recovery and reuse system for semiconductor substrate processing

Info

Publication number: US20250010431A1
Application number: US18/274,991
Authority: US
Inventors: Jianjun Hu; Peng Liu; Colin John Dickinson; Quoc Truong; Jamie Stuart Leighton; Gopalakrishna B. Prabhu; John Howard Givens
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2022-08-18
Filing date: 2022-08-18
Publication date: 2025-01-09
Also published as: TW202408734A; WO2024036569A1; EP4572913A1; KR20250047798A; CN119947855A; JP2025527505A

Abstract

The present disclosure generally relates to methods and system used to collect and reuse polishing fluids used during a chemical mechanical polishing (CMP) process for the fabrication of electronic devices. More specifically, systems and methods provided herein include a polishing fluid collection system having a catch basin, a vacuum device, and a polishing fluid recycling module for recycling polishing fluid.

Description

BACKGROUND

Field

Embodiments described herein generally relate to systems and methods used to process semiconductor substrates in an electronic device manufacturing process, and more particularly, to systems for collecting and reusing polishing fluids used in the chemical mechanical polishing (CMP) of a semiconductor substrate and substrate processing methods related thereto.

Description of the Related Art

Chemical mechanical polishing (CMP) is commonly used in the manufacturing 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, hence creating relative movement between the material layer surface and the polishing pad, in the presence of a polishing fluid. Material is removed across the material layer surface in contact with the polishing pad through a combination of chemical and mechanical activity, which is provided at least in part by the polishing fluid. Commonly used polishing fluids include abrasive particle-containing slurries, e.g., colloids or suspensions, 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.
Typically, polishing fluids are highly engineered to provide desired chemical and mechanical polishing performance characteristics and to disperse and keep the abrasive particles in a colloid or a relatively stable suspension. At least in part due to high costs of engineering and manufacturing CMP polishing fluids, CMP processes are often the most expensive substrate processing operations in the manufacturing of semiconductor devices.
Accordingly, in order to reduce costs associated with polishing fluids used in semiconductor device manufacturing, there is a need in the art for methods and systems for collecting and reusing polishing fluids used in a semiconductor substrate polishing process.

SUMMARY

The present disclosure generally relates to methods and system used to collect and reuse polishing fluids used during a chemical mechanical polishing (CMP) process for the fabrication of electronic devices.
In one embodiment, a polishing system is disclosed. The polishing system includes a catch basin sized to surround and to 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 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 inward facing surface of the catch basin is further defined by an arc radius which is equal to an arc radius of the platen that the catch basin is sized to surround. The inward facing surface of the catch basin configured to allow for a 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 apart therefrom the base portion. The suction tube is stationary in relation to the rotating catch basin. The polishing system further includes a polishing fluid recycle module. The suction tube draws a polishing fluid out of the trough and sends the polishing fluid to the polishing fluid recycle module for reuse.
In another embodiment, a fluid reuse system is disclosed. The system includes a platen, a polishing pad secured to the platen, 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 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 such that the catch basin rotates with the platen. The outer wall, the inner wall, and the base portion collectively define a trough. A radially inward facing surface of the catch basin is defined by an arc radius which is equal to a radius of the platen the catch basin is sized to surround. The fluid reuse 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 apart therefrom the base portion. The suction tube is stationary in relation to the rotating catch basin, allowing the vacuum device to collect the first polishing fluid. The fluid reuse system further includes a polishing fluid recycle 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 delivers the second polishing fluid to the polishing pad. The first polishing fluid may be delivered to the polishing pad at the same time by the first CLCSDS such that a mixture of first polishing fluid and second polishing fluid may be used, or alternatively the flow of first polishing fluid may be stopped and the polishing pad supplied by the second polishing fluid only.
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, urging the substrate against the surface of the polishing pad while rotating a platen, the platen having the polishing pad disposed thereon, collecting the polishing fluid using a fluid reuse system, filtering the polishing fluid of contaminants, and dispensing the polishing fluid collected using the polishing fluid catch basin onto the surface of the polishing pad. The fluid reuse system includes a catch basin coupled to the platen. The catch basin is configured to abut the platen and to rotate with the platen. At least some 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 comprising a suction tube disposed within the trough.
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

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1 is a schematic side view of a polishing system configured with a catch basin (shown in cross-section), according to embodiments.

FIG. 2 is a schematic perspective view of a portion of the catch basin shown in FIG. 1 , according to embodiments.

FIG. 3 is a schematic side view of a catch basin (shown in cross-section), according to embodiments.

FIG. 4A is a schematic perspective view of a vacuum device, according to embodiments.

FIG. 4B is a schematic side view of a vacuum device, according to embodiments.

FIG. 5 is a schematic diagram of a fluid reuse system, according to embodiments.

FIG. 6 is a schematic diagram of a polishing fluid recycle module of a fluid reuse system, according to embodiments.

FIG. 7 is a schematic diagram of a waste collection system that may be used with the fluid catch basin shown in FIGS. 1-6 , according to embodiments.

FIG. 8 is a schematic diagram of a controller unit configured to control the fluid reuse system and waste collection system, according to embodiments.

FIG. 9 is a flow diagram of the method of utilizing the fluid reuse system, according to embodiments.

In order 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 the elements and features of each embodiment may be beneficially incorporated into the other embodiments without further recitation.

DETAILED DESCRIPTION

Embodiments of the present disclosure generally provide a system for collecting and reusing polishing fluids, and methods related thereto. In particular, the system and methods provided herein feature a polishing fluid collection system used to collect and reuse polishing fluids dispensed during the chemical mechanical polishing (CMP) of a substrate in an electronic device manufacturing process.
In a conventional CMP process, polishing fluid is dispensed onto a surface of a polishing pad mounted on a rotating platen. The polishing fluid is dispensed onto the surface of the polishing pad and a substrate is urged 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 from the rotation of the platen. When the polishing fluid reaches the circumferential edge of the polishing pad, the polishing fluid typically flows into a drainage basin that surrounds the platen and extends into a region disposed below the platen. This facilitates capture of all of the fluids and other processing byproducts used during a CMP substrate process and other processing activities concomitant wherewith, e.g., pad rinsing and pad conditioning activities, as well as polishing byproducts related thereto. Often, the volume of non-polishing fluids far exceeds the volume of polishing fluid, such as by 5× more. Thus, the effluent from the drainage basin typically comprises highly diluted and contaminated polishing fluid. Therefore, embodiments herein provide for a polishing fluid capture system for capturing polishing fluid before the fluid would otherwise flow into the drainage basin, thus avoiding any contamination and dilution thereof.
Efforts at recycling polishing fluids have been largely unsuccessful at least in part due to the relatively low concentration of polishing fluid in the basin effluent as well as shifts in the compositions thereof. In addition, polishing processes often use more than one type of polishing fluid, each delivered to the polishing pad in sequence at different stages in a polishing process. The chemical compositions and the abrasives used in each of the different polishing fluids may be incompatible with one another, further complicating an effluent 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 fluids flow into the drainage basin and reuse the captured polishing fluids without the need for further costly treatments. Thus, embodiments herein may be used to substantially reduce the cost per substrate polished during a semiconductor device manufacturing process.
The polishing system hereof, in one aspect, comprises a catch basin disposed proximate to the rotatable platen. The catch basin is sized to surround and abut the platen and configured to couple to the platen such that the catch basin rotates with the platen. A vacuum device is disposed within a trough of the catch basin and is stationary in relation to the rotating catch basin. The vacuum device is used to draw the polishing fluid out of the trough of the catch basin and into a polishing fluid recycle modules for recycling the polishing fluid.
FIG. 1 is a schematic side view of a polishing system 100, according to one embodiment. Here, the polishing system 100 includes a cylindrical platen 102, a polishing pad 104 secured to the platen, e.g., by use of a pressure-sensitive adhesive, a substrate carrier 106 disposed above the platen 102 to face 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 urges a material surface of a substrate 108 disposed in the substrate carrier 106 against the polishing pad 104 while simultaneously rotating about a carrier axis 110. The platen 102 rotates about a platen axis 112 while the rotating substrate carrier 106 sweeps back and forth from an inner diameter to an outer diameter of the platen 102 to, in part, reduce uneven wear of the polishing pad 104. In some embodiments, the polishing system 100 further includes a pad conditioner assembly (not shown) that is used to abrade, rejuvenate, and remove polish byproducts or other debris from the surface of the polishing pad 104.
As shown, polishing fluids, polishing fluid additives, cleaning fluids, and/or deionized (DI) water are delivered to a fluid dispense arm 114 positioned over the platen 102 from a polishing fluid source 126 and are dispensed onto the polishing pad 104 using nozzles 116 positioned in the fluid dispense arm 114. The fluid dispense arm 114 is coupled to an actuator 118, which positions the fluid dispense arm 114 over the platen 102 by swinging the fluid dispense arm 114 thereover. The actuator 118 is disposed on a base plate 120 that surrounds the platen 102. A system controller 800, as discussed further below, controls the actuator, the amount of polishing fluid that is dispensed by the fluid dispense arm 114, and a fluid reuse system 500 (discussed below).
Referring to FIGS. 2 & 3 , the catch basin 200 (shown in cross-section in FIG. 1 ) is sized to surround and to 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, which is shown in FIG. 1 as having a U-shaped profile in cross section, although 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 a polishing fluid chemically resistant polymer having a hydrophobic surface. Examples of suitable polymers include fluorine-containing polymers (fluoropolymers), such as perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE) commercially available as TEFLON® from DuPont, or combinations thereof. In some embodiments, the base portion 214 of the catch basin 200 is an annular ring that surrounds the platen 102 and is fixedly coupled thereto. The base portion 214 is configured to have a plurality of holes 222 configured to receive a plurality of fasteners 220. The fasteners couple the catch basin 200 to the platen 102 such that the catch basin 200 rotates about the platen axis 112 with the polishing pad 104.
The catch basin 200 collects the polishing fluid which is spun radially outward from the rotating polishing pad 104 due to the centrifugal force imparted thereto. The catch basin, in one embodiment, is approximately 2 ft. in diameter. The outer wall 212 is spaced apart from the inner wall 210 by a width W(1) of the trough 202 which is between about 0.5 cm and about 5 cm. A 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 from the base portion 214 in the Z-direction by a height H(1), although different heights for each of the walls may be used. The radially inward facing surface 230 of the catch basin 200 is further defined by an arc radius which is equal to an arc radius of the polishing pad 104 that the catch basin 200 is sized to surround. This allows for all of the polishing fluid to flow radially outward from the surface of the polishing pad 104 into the trough 202 and not fall in between the catch basin 200 and the polishing pad 104.
Referring to FIG. 4 , the catch basin 200 further includes a vacuum device 400. The vacuum device 400 includes a suction tube 402. The catch basin 200 does not include a gravity type drain or opening that can be used to drain polishing fluids from the trough 202. Fluid collection efficiency of gravity drain systems can be inadequate owing to the liquid dispersing over large surface areas, 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 apart therefrom the base portion 214 in order to avoid wear on the suction tube 402 while still allowing sufficient suction. Thus, polishing fluids are extracted from the trough 202 by use of the suction tube 402. The vacuum device 400 is configured to be stationary in relation to the rotating catch basin 200, although it is conceived that the tube may have ability for control of its movement by actuation devices to optimize fluid collection or remove the collection tube for service. The vacuum 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. As the polishing fluid flows from the polishing pad 104 and into the trough 202, the vacuum device 400 draws the polishing fluid out of the trough 202.
In some embodiments, the catch basin 200 is coupled to a Z-actuator which is configured to raise and lower the catch basin 200 in the Z-direction. In those embodiments, the radially inward facing surface 230 of the catch basin 200 is defined by an arc radius which is larger than the arc radius of the polishing pad 104 that the catch basin 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 inward facing surface 230 of the catch basin 200 and the arc radius of the polishing pad 104. In those embodiments, the catch basin 200 is raised when a fluid which is undesirable for reuse is dispensed onto the polishing pad 104. In the raised position, the radially inward facing surface 230 and the lip 240 obstruct fluid flowing off of the edge of the polishing pad from entering a trough 202 of the catch basin 200. Thus, the fluid which is undesirable for reuse flows 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 into a drainage basin 122 (shown in FIG. 1 ) disposed therebelow. When polishing fluid desired for reuse is dispensed onto the polishing pad 104, the catch basin 200 is lowered into a fluid collection position and the desired polishing fluid for reuse is collected using the methods described herein.
Referring to FIGS. 5A, 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 comprises a first closed loop control 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 through the fluid dispense arm 114 to the polishing pad 104 of one of the polishing systems 100. The polishing fluid source 126 comprises a centralized or local 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 typically has not yet been used in a substrate CMP processing operation. The first polishing fluid 506 is then collected by the catch basin 200 and drawn out of the catch basin 200 by the vacuum 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 vacuum device 400 and recycles/filters the first polishing fluid 506 to make a second polishing fluid 508. The second polishing fluid 508 is then provided to the second CLCSDS 504 for delivery to the platen. When the second polishing fluid 508 is delivered to the platen 102, flow of the first polishing fluid 506 may be stopped by the first CLCSDS 502 such that the system 500 may operate continuously with the second polishing fluid 508. Alternatively, the flow rate of first polishing fluid 506 and flow rate of second polishing fluid 508 may be adjusted to provide a mixture of first polishing fluid 506 and second polishing fluid 508 to the platen 102. This allow the first polishing fluid 506 to provide for any losses in the collection process and for preferential process tuning of the blend ratio of the first polishing fluid 506 and second polishing fluid 508 for optimum substrate 108 polishing. In another embodiment, shown in FIG. 5B, the system 500 includes a static mixer 560 to premix the first polishing fluid 506 and the second polishing fluid 508 prior to delivery of the polishing fluid to the platen 102.
In one embodiment, as referred to in FIG. 6 , the polishing fluid recycle module 501 further comprises a first tank 610 and a second tank 612. The vacuum generator 620 provides vacuum suction to first tank 610 and enables the first polishing fluid 506 to be drawn 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 has been filled with polishing fluid, the vacuum generator 620 switches to pressure delivery mode to pressurize the first tank 610 and enable the first polishing fluid 506 to be moved around the polishing fluid recycle module 501 into the second tank 612 for holding and to provide agitation to the first polishing fluid 506. The vacuum generator 620 may utilize 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 may be a Venturi system. The first polishing fluid 506 is in continuous motion in order to keep the first polishing fluid 506 in suspension. The polishing fluid transfer from first tank 610 to second tank 612 dispenses the fluid around the polishing fluid recycle module 501 to the second CLCSDS 504, at which point the second CLCSDS 504 may consume a portion or all of the polishing fluid and delivers the polishing fluid to the polishing system 100. Particulate matter with particle size greater than the particle size of the polishing fluid is filtered out of the first polishing fluid 506 by addition of the filter 615 during the recirculation process to move fluid from first tank 610 to second tank 612. 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 configured to be opened in order to enable flushing and cleaning of the fluid reuse system 500 during maintenance.
In one embodiment, as shown in FIG. 6 , the fluid reuse system 500 incorporates multiple platens, e.g., first polishing platen 630, second polishing platen 640, and third polishing platen 650. The fluid recycle module 501 may interact with these platens to collect polishing fluid for one platen, all platens, or a combination thereof. This allows for flexibility to collect the polishing fluid from specific processes only of to maximize collection of polishing fluid from all platens simultaneously. The delivery of the recirculated fluids to the CLCSDS 504 may be dispensed to just one platen, all platens, or a combination thereof.
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 system before being polished using the first polishing fluid 506 from the polishing fluid source 126, or vice versa. In at least one embodiment, a substrate 108 is polished using only the second polishing fluid 508 collected using the fluid reuse system 500 for a first period time before being polished for a second period of time using only the first polishing fluid 506 from the polishing fluid source 126. Polishing the substrate 108 with only the first polishing fluid 506 from the polishing fluid source 126 for the second period time ensures that any possible defects to the substrate 108 surface caused by trace contaminants or agglomerations in the second polishing fluid 508 collected using the fluid reuse system 500 are removed from the substrate 108 surface. In some embodiments, dispensing the second polishing fluid 508 collected using the fluid reuse system 500 is alternated with dispensing 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 this disclosure.
In another embodiment, the fluid reuse system 500 includes a plurality of polishing fluid recycle modules 501. This embodiment allows for multiple different polishing fluids to be collected independently and reused specifically at the platen or platens on which they were used in the process.
Referring to FIG. 7 , the fluid reuse system further comprises a waste collection system 700. The waste collection system 700 includes a second vacuum device 705 disposed within the trough 202 of the catch basin 200 and configured to collect waste fluids 708 from the trough 202. The waste collection system 700 further includes a waste tank 710 and a vacuum generator 720. The waste fluid 708 is drawn out of the trough 202 of the catch basin 200 and separated from the first polishing fluid 506 by the second vacuum device 705, which is activated to collect fluid during a period that rinse or cleaning fluids are flowing after or before the slurry polishing process. The vacuum force of the second vacuum device 705 is generated using the vacuum generator 720, which draws the waste fluid 708 into the waste tank 710. The waste collection system 700 then drains the waste fluid 708 from the fluid reuse system 500 through a second drain 702. In one embodiment, the waste collection system further comprises a second clean valve 740, the second clean valve 740 configured to be opened in order to allow flow of cleaning fluids directly to the catch basin 200 for cleaning purposes.
Referring to FIG. 8 , the polishing system 100 further includes a system controller 800 to direct the operation thereof, which includes direction the operation of the fluid reuse system 500. The system controller 800 includes a programmable central processing unit, such as the 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 comprise cache, clock circuits, input/output subsystems, power supplies, and the like, and combinations thereof coupled to the various components of the polishing system 100, to facilitate control thereof. The CPU 802 is one of any form of general purpose computer processor used in an industrial setting, such as a programmable logic controller (PLC), for controlling various components and sub-processors of the polishing system 100. The memory 804, coupled to the CPU 802, is non-transitory and is typically one or more of readily available memories such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote.
The memory 804 is in the form of a computer-readable storage media containing instructions (e.g., non-volatile memory), which, when executed by the CPU 802, facilitates the operation of the polishing 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 others. The machine learning capabilities are capable of optimizing the amounts of the first polishing fluid 506 that are mixed with the second polishing fluid 508 to reduce the cost of polishing and the amount of maintenance time required, as well as other parameters such as pH, oxygen levels, and the possibility for acid addition for pH adjustment and control.
The memory 804 is configured to store a plurality of instructions for running operations on the polishing system 100. For example, the memory 804 can hold instructions that designate what percentage of the first polishing fluid 506 is mixed with the second polishing fluid 508. The memory 804 can hold instructions that designate the rotation speed of the platen 102 around the platen axis 112 or the substrate carrier 106 around the carrier axis 110. The memory 804 can hold instructions for controlling the flow of the first and second polishing fluids 506, 508, i.e., for when to change from the first polishing fluid 506 to the second polishing fluid 508 or vice versa. In addition, the memory 804 can hold instructions for how the polishing process should proceed in the event that the fluid reuse system 500 is undergoing maintenance or has malfunctioned.
The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on computer-readable storage media for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein).
Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. 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 set forth 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 set forth herein are performed by a combination of software routines, ASIC(s), FPGAs and, or, other types of hardware implementations.
Referring to FIG. 9 , a flow diagram setting forth a method of polishing a substrate using the fluid reuse system 500 will now be briefly described. The method includes action 901, dispensing a first polishing fluid onto a surface of a polishing pad 104. The polishing pad 104 is disposed on a surface of a platen 102, such as the platen 102 of the polishing system 100 described in FIG. 1 . The first polishing fluid 506 is dispensed onto the polishing pad 104 using a fluid dispense arm 114 positioned thereabove.
The method further includes action 902, urging a 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 to have the polishing pad 104 disposed thereon the platen 102.
The method further includes action 903, 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, which is on the rotating polishing pad 104, flows toward the edge of the pad and then outwardly away from the platen into a trough 202 of a catch basin 200, as described in FIGS. 1-3 , which is disposed about at least a portion of the platen 102. A vacuum device 400 then collects the first polishing fluid 506 from the trough 202 and sends it to a polishing fluid recycle module 501
The method further includes action 904, filtering the dispensed polishing fluid of contaminants. From the trough 202 of the catch basin 200, the first polishing fluid 506 is directed towards one of a storage vessel (i.e., first tank 610) of the polishing fluid recycle module 501 using a valve fluidly coupled therebetween. An inlet to the valve is further fluidly coupled to a suction tube 402 of a vacuum device 400. Once the first tank 610 is full of 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 which contains a filter 615 to polish the first polishing fluid 506 into a second polishing fluid 508.
The method further includes action 905, dispensing the 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 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 system 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 a substrate 108 is polished using only the second polishing fluid 508 collected using the fluid reuse system 500 for a first period time before being polished for a second period of time using only the first polishing fluid 506 from the polishing fluid source 126. Polishing the substrate 108 with only the first polishing fluid 506 from the polishing fluid source 126 for the second period time ensures that any possible defects to the substrate 108 surface caused by trace contaminants or agglomerations in the second polishing fluid 508 collected using the fluid reuse system 500 are removed from the substrate 108 surface. In some embodiments, dispensing the second polishing fluid 508 collected using the fluid reuse system 500 is alternated with dispensing 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.
Beneficially, the system and methods provided herein facilitate the collection and reuse of expensive CMP polishing fluids without substantial reprocessing thereof.
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 thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1. A polishing system, comprising:

a catch basin sized to surround and to abut a polishing pad secured to a platen, the catch basin comprising:

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 configured to couple the catch basin to the platen such that the catch basin rotates with the platen and the polishing pad, wherein:

the outer wall, the inner wall, and the base portion collectively define a trough; and

a radially inward facing surface of the catch basin is further defined by an arc radius which is equal to an arc radius of the platen that the catch basin is sized to surround, the radially inward facing surface of the catch basin configured to allow for a polishing fluid to flow radially outward from the polishing pad into the trough;

a first vacuum device, the first vacuum device comprising a suction tube; wherein the suction tube is disposed within the trough of the catch basin, wherein the suction tube is stationary in relation to the catch basin when rotating; and

a polishing fluid recycle module, wherein the first vacuum device draws a polishing fluid out of the trough and sends the polishing fluid to the polishing fluid recycle module for reuse.

2. The polishing system of claim 1, wherein the suction tube is sized to be spaced apart 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 a top portion of the inner wall comprises a beveled edge on a trough facing surface of the inner wall.

6. The polishing system of claim 1, wherein the base portion comprises a plurality of holes, the holes being configured to receive a fastener, wherein the fastener couples the catch basin to the platen such that the catch basin rotates with the platen 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 trough, wherein the first vacuum device is configured to collect a polishing fluid, and wherein the second vacuum device is configured to collect waste fluids.

8. A fluid reuse system, the system comprising:

a platen;

a polishing pad secured to the platen;

a first and a second closed loop control slurry delivery system (CLCSDS), wherein the first CLCSDS delivers a first polishing fluid to the polishing pad, wherein the first polishing fluid is collected by a catch basin, the catch basin comprising:

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 configured to couple the catch basin to the platen such that the catch basin rotates with the platen, wherein:

a radially inward facing surface of the catch basin is defined by an arc radius which is equal to a radius of the platen the catch basin 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 trough of the catch basin and to be spaced apart therefrom the base portion, and wherein the suction tube is stationary in relation to the catch basin when rotating; wherein the first vacuum device collects the first polishing fluid;

a polishing fluid recycle module, the polishing fluid recycle module configured to recycle the first polishing fluid into a second polishing fluid, wherein the second polishing fluid is provided to the second CLCSDS; and

wherein the second CLCSDS delivers the second polishing fluid the platen and the first CLCSDS delivers the first polishing fluid to the platen 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 both.

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 being configured to control a flow of the first and second polishing fluids.

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

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

12. The fluid reuse system of claim 10, wherein the controller further comprises adding quantities of acid to modify the pH of the first and second polishing fluids.

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

16. The fluid reuse system of claim 15, wherein the fluid reuse system further comprises a waste collection system, the waste collection system separating the waste fluid collected by the second vacuum device from the first polishing fluids in the catch basin and drain the waste fluid from the fluid reuse system.

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

18. A method of polishing a substrate, comprising:

dispensing a polishing fluid onto a surface of a polishing pad;

urging the substrate against the surface of the polishing pad while rotating a platen, the platen having the polishing pad disposed thereon;

collecting the polishing fluid using a fluid reuse system, wherein:

the fluid reuse system comprises a catch basin coupled to the platen, the catch basin being configured to abut the platen and to rotate with the platen; and

at least some of the polishing fluid dispensed onto the polishing pad being collected in a trough of the catch basin;

the polishing fluid being collected by a vacuum device, the vacuum device comprising a suction tube disposed within the trough;

filtering the polishing fluid of contaminants; and

dispensing the polishing fluid collected using the catch basin onto the surface of the polishing pad.

19. 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, wherein the inner wall, the outer wall, and the base portion collectively define the trough.

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