Apparatus and method of brush cleaning using periodic chemical treatments

Abstract

A chemical mechanical polishing (CMP) system includes apparatus and methods for cleaning brushes used for washing a substrate, including brush cleaning using periodic chemical treatments. One or more embodiments include a method that operates the CMP system to: rotate a first one or more washing brushes while simultaneously bringing the first one or more washing brushes into contact with a first substrate; perform a cleaning operation on a second one or more washing brushes during the rotation during a first duration; perform the cleaning operation on the first one or more washing brushes during a second duration of the cleaning cycle; and rotate the second one or more washing brushes while performing the cleaning operation during the second duration, simultaneously bringing the second one or more washing brushes into contact with a second substrate.

Description

Equipment and Method for Brush Cleaning Using Periodic Chemical Treatment Embodiments of the present disclosure generally relate to a cleaning module for washing a substrate, and more particularly to equipment and methods for brush cleaning using periodic chemical treatment. Integrated circuits are typically formed on a substrate (e.g., a semiconductor wafer) by sequentially depositing conductive, semiconductor, or insulating layers on the substrate and by subsequent processing of these layers. One manufacturing step involves depositing a filler layer over a non-planar surface disposed on a substrate and planarizing the filler layer until the non-planar surface is exposed. For example, a conductive filler layer can be deposited on a patterned insulating layer disposed on a substrate to fill trenches or holes in the insulating layer. The filled layer is then polished until the raised pattern of the insulating layer is exposed. Chemical mechanical polishing (CMP) is a well-known and recognized planarization method in the art. Such a planarization method typically requires mounting the substrate on a carrier head. The exposed surface of the substrate is placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to press the substrate against the polishing pad. For example, the carrier head can provide a specified pressure on the back surface of the substrate to press the substrate against the polishing pad. A polishing fluid (such as a slurry having abrasive particles) is supplied to the surface of the polishing pad. For example, a cerium-based slurry (such as a slurry containing cerium oxide) can be used to polish semiconductor or insulating thin layers in CMP. After polishing, the slurry residue is typically cleaned or washed off the substrate surface via a mechanical washing device (which can employ a washing brush). Such brushes can be made of polyvinyl acetate (PVA), other porous or spongy materials, or nylon bristles, etc. When the brush is clean, the washing device can remove most of the slurry and other particulates from the surface of the substrate, but after cleaning one or more substrates, the brush may be loaded with residual slurry and particulates, and streaks or other residues may be found on the surface of the substrate after applying the mechanical washing device. Therefore, it is necessary to clean the washing brush to remove the residual slurry and particulates to improve the effectiveness of the cleaning process. One technique for cleaning the washing brush is to apply or spray a cleaning solution directly or indirectly onto the brush while applying the mechanical washing device to the substrate. In such a case, the chemical nature of the cleaning fluid should be compatible with the substrate, including any features, elements, components, layers, etc. formed on or in the substrate. However, cleaning the washing brush using a compatible cleaning fluid may be slow, or the effect may be unsatisfactory, or both. Another technique may involve using a cleaning fluid that cleans the scrub brush more effectively but is chemically incompatible with the substrate. In such a case, the cleaning of the substrate can be temporarily paused so that the cleaning fluid can be applied to the scrub brush without the substrate. After cleaning the scrub brush, the cleaning of the substrate can be resumed. Although such a technique cleans the scrub brush more effectively, the substrate throughput will be reduced because the overall substrate cleaning sequence will be slowed down due to the temporary pause required to clean the scrub brush. Accordingly, there is a need in the art for improved apparatus and methods for cleaning brushes used in chemical mechanical polishing. The embodiments described herein generally relate to a cleaning brush for cleaning the surface of a substrate. More specifically, the embodiments described herein provide apparatus and methods for brush cleaning using periodic chemical treatment. One or more embodiments include a method of operating a chemical mechanical polishing (CMP) system. The method includes rotating first one or more scrub brushes in a first brush cleaner of the CMP system during a first duration of a cleaning cycle while contacting the first one or more scrub brushes with a first substrate. The method further includes performing a cleaning operation on second one or more scrub brushes in a second brush cleaner of the CMP system while rotating during the first duration. The method further includes performing a cleaning operation on the first one or more scrub brushes in the first brush cleaner during a second duration of the cleaning cycle. The method further includes rotating the second one or more scrub brushes while performing the cleaning operation during the second duration while contacting the second one or more scrub brushes with a second substrate. In one or more embodiments, the CMP system includes: a first brush cleaner that houses first one or more scrub brushes; a second brush cleaner that houses second one or more scrub brushes; and a system controller. The system controller is configured to simultaneously control the first brush cleaner and the second brush cleaner to rotate the first one or more scrub brushes while contacting the first one or more scrub brushes with a first substrate. The system controller is further configured to simultaneously control the first brush cleaner and the second brush cleaner to perform a cleaning operation on the second one or more scrub brushes while rotating during the first duration. The system controller is further configured to simultaneously control the first brush cleaner and the second brush cleaner to perform a cleaning operation on the first one or more scrub brushes during a second duration of the cleaning cycle. The system controller is further configured to simultaneously control the first brush cleaner and the second brush cleaner to rotate the second one or more scrub brushes while performing the cleaning operation during the second duration while contacting the second one or more scrub brushes with a second substrate. In one or more embodiments, a CMP system includes: a first brush cleaner that houses first one or more wash brushes; a second brush cleaner that houses second one or more wash brushes; and a computer-readable medium that stores instructions. The instructions, when executed by a processor of the CMP system, cause the CMP system to rotate the first one or more wash brushes while contacting the first one or more wash brushes with a first substrate. The instructions further cause the CMP system to perform a cleaning operation on the second one or more wash brushes while rotating during a first duration. The instructions further cause the CMP system to perform a cleaning operation on the first one or more wash brushes during a second duration of a cleaning cycle. The instructions further cause the CMP system to rotate the second one or more wash brushes while performing the cleaning operation during the second duration while contacting the second one or more wash brushes with a second substrate. Embodiments of the present disclosure provided herein generally relate to cleaning brushes for cleaning substrates, such as cleaning substrates after a chemical mechanical polishing (CMP) process. More specifically, the embodiments described herein provide an apparatus and method for brush cleaning a substrate provided in a cleaning sequence during which a periodic chemical treatment of the brush cleaning apparatus is performed. During a CMP process, a film being polished may redeposit on the surface of a substrate (e.g., a wafer), and polishing process components (e.g., abrasive particles or polishing pad, carrier ring or conditioner disk debris) may form residues on the surface of the substrate. When the brush of a brush cleaner is applied to a substrate during a substrate cleaning operation to remove the film, debris from the film and remaining slurry components may accumulate on the brush. A cleaning solution may be applied to the brush to remove residues from the brush. However, such a cleaning solution may also etch the film off the substrate. In one or more embodiments described herein, the brushes of a brush cleaner may be periodically cleaned in the absence of a substrate. In one or more embodiments, two or more brush cleaners are used in a CMP system such that during a given duration, the brushes of a first idle brush cleaner may be cleaned while a second brush cleaner loaded with a substrate may operate the brush to clean the substrates. One or more embodiments include a cleaning mode by which two or more brush cleaners may be used to alternate the duration of cleaning the brushes of a brush cleaner and performing a substrate cleaning operation using the brush cleaner. By alternating, the brush cleaners may be effectively used to increase the substrate cleaning throughput using the brush cleaners and to provide a cleaned brush to be applied to a substrate by the brush cleaner during a substrate cleaning operation, thereby improving the cleanliness of the substrate and maintaining or increasing the substrate cleaning throughput. Exemplary Chemical Mechanical Polishing System FIG. 1 shows a schematic top view of a chemical mechanical polishing (CMP) system 100. The system 100 generally includes a factory interface module 102, an input module 104, a polishing module 106, and a cleaning module 108. These four main components are generally disposed within the CMP system 100. The factory interface 102 includes a support for holding a plurality of substrate cassettes 110, a housing 111 that encloses the chamber, and one or more interface robots 112. The factory interface robot 112 generally provides the range of motion required to transfer substrates between the cassette 110 and one or more of the other modules of the system 100. Unprocessed substrates are generally transferred from the cassette 110 to the input module 104 by the interface robot 112. The input module 104 generally facilitates the transfer of substrates between the interface robot 112 and a transfer robot 114. The transfer robot 114 transfers substrates between the input module 104 and the polishing module 106. The polishing module 106 generally includes a transfer station 116 and one or more polishing stations 118. The transfer station 116 is disposed within the polishing module 106 and is configured to receive substrates from the transfer robot 114. The transfer station 116 transfers the substrates to a carrier head 124 of the polishing station 118, which holds the substrate during polishing. Each polishing station 118 includes a rotatable platen, and a polishing pad 120 is located on the rotatable platen. The platen is operable to rotate about an axis. The polishing pad 120 can be a two-layer polishing pad having an outer polishing layer and a softer backing layer. Each polishing station 118 further includes a dispensing arm 122 to dispense a polishing fluid (e.g., a polishing slurry) onto the polishing pad 120. In the polishing slurry, the abrasive particles can be silicon oxide, but some polishing processes use cerium oxide abrasive particles. Each polishing station 118 may also include a conditioner head 123 to maintain the polishing pad 120 at a consistent surface roughness. Each polishing station 118 includes at least one carrier head 124. The carrier head 124 is operable to hold the substrate against the polishing pad 120 during a polishing operation. After performing the polishing operation on the substrate, the carrier head 124 transfers the substrate back to the transfer station 116. The transfer robot 114 then removes the substrate from the polishing module 106 via an opening that connects the polishing module 106 to the remainder of the CMP system 100. The transfer robot 114 removes the substrate from the polishing module 106 in a horizontal orientation and transfers the substrate to the cleaning module 108. The cleaning module 108 generally includes one or more cleaning devices that can operate independently or in concert. For example, the cleaning module 108 may include, from top to bottom in FIG. 1, one or more pre-cleaning modules 129, three or more brush cleaners 131, a megahertz ultrasonic cleaner 133, and a dryer 134. Other possible cleaning devices include chemical spin cleaners and spray cleaners (not shown). A transport system, such as the overhead transporter 130 that supports the robotic arm, can escort or move the substrate from one cleaning device to another. Additionally, an overhead transfer robot can also be used for such substrate transport. As will be discussed further below, the three or more brush cleaners 131 are devices where the substrate can be placed and the surface of the substrate contacts a rotating brush or a spin polishing pad to remove any remaining particles. The substrate is then transferred to the megahertz ultrasonic cleaner 133, where high-frequency vibrations generate controlled cavitation in the cleaning liquid to clean the substrate. Alternatively, the megahertz ultrasonic cleaner 133 can be positioned before the brush 131 or the pre-cleaning module 129. The final rinse can be performed in a rinse module before being transferred to the drying module 134. As described above, the CMP system 100 transfers the substrate from the polishing module 106 to the cleaning module 108. Debris from the polishing process (such as abrasive particles or organic materials from the polishing pad or slurry) may adhere to the substrate. Some of these materials (such as abrasive particles and organic additives from the polishing module 106) are difficult to remove. The system controller 140, such as a programmable computer, is coupled to the rest or components of the system 100. In one or more embodiments, the system controller 140 can control the operation of one or more of the factory interface module 102, the input module 104, the polishing module 106, and the cleaning module 108 (including one or more of its components, including each of the brush cleaners 131 in the brush cleaners 131). In operation, the system controller 140 enables data collection and feedback to coordinate the operation of the factory interface module 102, the input module 104, the polishing module 106, and the cleaning module 108 (including one or more of its components, including each of the brush cleaners 131 in the brush cleaners 131). The system controller 140 includes a programmable central processing unit (CPU) 142 that can operate with a memory 144 (e.g., non-volatile memory) and support circuitry 146. The support circuitry 146 (e.g., cache memory, clock circuits, input / output subsystems, power supplies, etc., and combinations thereof) is coupled to the CPU 142 in a conventional manner and is coupled to various other components of the system 100. In some embodiments, the CPU 142 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 monitoring system components and sub-processors. The memory 144 coupled to the CPU 142 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 drives, hard disks, or any other form of local or remote digital storage device. Here, the memory 144 is in the form of a computer-readable storage medium (e.g., non-volatile memory) containing instructions that, when executed by the CPU 142, facilitate the operation of the system 100. The instructions in the memory 144 are in the form of a program product, such as a program implementing the methods of the present disclosure (e.g., middleware applications, device software applications, etc.). The program code can conform to any one of a variety of different programming languages. In one example, the present disclosure can be implemented as a program product stored on a computer-readable storage medium for use by a computer system. The program of the program product defines the functions of the various embodiments, including the methods described herein. Exemplary 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) that permanently store information; and (ii) writable storage media (e.g., floppy disks in a disk drive or hard disk drives or any type of solid-state random access semiconductor memory) that store variable information. 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. Exemplary washing devices capable of performing brushing and cleaning FIG. 2A is an isometric view of the brush cleaner 131 that can be used in the cleaning module 108 as described above. For ease of discussion, the cover portion (which includes the door) of the brush cleaner 131 has been removed from FIGS. 2A and 2B. The brush cleaner 131 shown in FIG. 2A can be a washer-type brush cassette vertical cleaner. The exemplary brush cleaner 131 includes a trough 205 supported by a first support 225 and a second support 230. The brush cleaner 131 includes actuators 235, each of which is coupled to a cylindrical roller 228 located within the trough 205. The actuators 235 can each include a drive motor, such as a direct drive servo motor, that is adapted to rotate the corresponding cylindrical roller about axes A' and A''. Each of the actuators 235 is coupled to the system controller 140, which is adapted to control the rotational speed of the cylindrical rollers. The link 210 and the actuator 245 are configured to allow the cylindrical rollers 228 located within the trough 205 to move relative to the main surface of the substrate 200 (illustrated in FIG. 2B). The actuator 245 is coupled to the controller to control the movement of the link 210 relative to the substrate disposed between the cylindrical rollers 228. In operation, the first support 225 and the second support 230 can move simultaneously relative to the base 240. Such movement can bring the first and second cylindrical rollers 228 into contact with the substrate 200 as shown in FIG. 2C, or space the first and second cylindrical rollers 228 apart as shown in FIG. 2D to allow the substrate 200 to be inserted into and / or removed from the brush cleaner 131. FIG. 2B is a top view of the brush cleaner 131 in FIG. 2A, illustrating the cylindrical rollers 228 in the processing position where the cylindrical rollers 228 are closed or pressed against the main surface of the substrate 200. The brush cleaner 131 also includes one or more drive motors 244 and rotating devices 247. Each of the drive motors 244 and the rotating devices 247 includes a roller 249 that is disposed at the end of the output shaft of each drive motor 244 and rotating device 247 and is configured to support and / or engage the substrate 200 and facilitate rotation of the substrate 200 about an axis parallel to the horizontal plane (i.e., the X-Y plane). Each of the cylindrical rollers 228 in the cylindrical roller includes a tubular cover (tubular covers 213a, 213b, illustrated in FIGS. 2C and 2D; not illustrated in FIG. 2B) provided thereon. The tubular covers 213a, 213b may be removable sleeves made of a pad material for polishing the substrate 200, or a brush body suitable for cleaning the substrate 200. The tubular covers 213a, 213b are also referred to herein as washing brushes. During processing in the brush cleaner 131, the tubular covers 213a, 213b of the cylindrical rollers 228 are brought into contact with the substrate while being rotated by the actuator 235, and at the same time the substrate 200 is rotated by the support rollers 249, which are coupled to the output shafts of the drive motor 244 and the rotating device 247. A second processing fluid (such as deionized (DI) water and / or one or more second substrate cleaning fluids (e.g., an aqueous solution containing an acid or a base)) is applied from a second fluid source to the surface of the substrate 200 while the substrate 200 and the cylindrical rollers 228 are rotated by various actuators and motors. According to one embodiment, a dedicated adjustment device 260 may be provided for each of the cylindrical rollers 228 in the cylindrical roller. The adjustment device 260 may also be referred to as a "stirring rod". The adjustment device 260 is mounted near the side wall of the groove 205 by one or more support members 270. The adjustment device 260 is positioned away from the center of the groove 205 so as not to interfere with the substrate transfer and / or the substrate polishing or cleaning process. However, the adjustment device 260 is positioned to contact each of the cylindrical rollers 228 in the cylindrical roller when the first support member 225 and the second support member 230 are actuated downward and outward away from each other. In one embodiment, the movement of the first support member 225 and the second support member 230 brings the cylindrical rollers 228 into contact with the corresponding adjustment device 260. In this position, the processing surfaces of the tubular covers 213a, 213b on each of the cylindrical rollers 228 in the cylindrical roller can be adjusted during the relative movement between the cylindrical roller 228 and the adjustment device 260. In one or more embodiments, a dedicated adjustment device 260 ("stirring rod") is used during the brush cleaning operation to enhance the brush cleaning. Figure 2C is a perspective view of one or more embodiments of a washing device 211 disposed within a scrubber 131. The washing device 211 shown in Figure 2C is depicted as having a substrate 200 loaded therein such that the washing device 211 is in a loaded state 233. The washing device 211 includes a pair of cylindrical rollers 228, the pair of cylindrical rollers including a pair of tubular caps 213a, 213b. In one or more embodiments, the pair of tubular caps 213a, 213b are polyvinyl acetate (PVA) brushes. Each brush includes a plurality of raised knots 215 across the surface of the brush, and a plurality of valleys 217 located between the knots 215. The pair of cylindrical rollers 228 are supported by pivot mounts (generally denoted by reference numeral 218), the pivot mounts adapted to move the pair of tubular caps 213a, 213b of the cylindrical rollers 228 into and out of contact with a substrate 200 (e.g., a semiconductor wafer) supported by a substrate support (which may also be referred to as a wafer support), thereby allowing the cylindrical rollers 228 to move between a closed position and an open position to allow the substrate 200 to be removed from between them and inserted between them, as described below. The washing device 211 also includes a substrate support adapted to support and further adapted to rotate the substrate 200. In one aspect, the substrate support may include a plurality of rollers 249a to 249c (Figures 2C to 2D), each roller having a groove adapted to vertically support the substrate 200. A first motor (or motors) of an actuator 235 is coupled to the cylindrical rollers 228 and adapted to rotate the tubular caps 213a, 213b of the cylindrical rollers 228 in rotational directions 203, 204, respectively. A second motor 244 is coupled to rollers 249a and 249c, respectively, and adapted to rotate rollers 249a and 249c, while a third motor 247 is coupled to roller 249b and adapted to rotate roller 249b. The washing device 211 may further include a plurality of nozzles 221 (including at least 221a, 221b, 221c, and 221d), the plurality of nozzles being coupled via a supply conduit 226 to a source 223 of substrate cleaning fluid. The nozzles 221 may be positioned to spray substrate cleaning fluid (e.g., deionized (DI) water, dilute ammonium hydroxide (NH 4 OH), dilute hydrogen peroxide (H 2 O 2 )、NH 4 OH and H 2 O 2Mixture (SC1), dilute hydrofluoric acid, sulfuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) mixture (SPM), Electra cleaner, or any other liquid solution for substrate cleaning). In one or more embodiments, the substrate cleaning fluid and / or the brush cleaning fluid discussed below can be supplied from the internal region of the scrub brush itself (e.g., the cylindrical roller 228 and the tubular caps 213a, 213b). The fluid provided to the interior of the scrub brush will pass through the pores in the tubular cap 213 to clean the surface of the substrate or remove debris found on the surface of the scrub brush. FIG. 2B is a perspective view of one or more embodiments of the washing device 211 of the brush cleaner 131 depicted when no substrate is loaded, such that the washing device 211 is in the idle state 234. In the idle state 234, the washing device 211 can perform a brush cleaning operation. In one or more embodiments, when performing the brush cleaning operation, the washing device 211 is not available for performing a substrate cleaning operation. The plurality of nozzles 221 are coupled via a supply conduit 226 to a source 223 of the brush cleaning fluid. The nozzles 221 can be positioned to spray the brush cleaning fluid at one or more scrub brushes (e.g., including the tubular caps 213a, 213b). In one or more embodiments, the brush cleaning fluid can be supplied via the scrub brush itself. In one or more embodiments, the brush cleaning fluid is the same as the substrate cleaning fluid (e.g., deionized (DI) water, dilute ammonium hydroxide (NH 4 OH), dilute hydrogen peroxide (H 2 O 2 ), NH 4 OH and H 2 O 2 Mixture (SC1), dilute hydrofluoric acid, sulfuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) mixture (SPM), Electra cleaner). In one or more embodiments, the brush cleaning fluid is different from the substrate cleaning fluid. For example, the brush cleaning fluid is hydrofluoric acid (e.g., dilute hydrofluoric acid), SPM, or SC1 (e.g., hydrogen peroxide), and the substrate cleaning fluid is a solution different from hydrofluoric acid, SPM, or SC1. In such a case, it is desirable to use a brush cleaning fluid that is configured to effectively clean the surface of the scrubbing brush and remove debris from such surfaces to improve subsequent substrate cleaning steps. However, such brush cleaning chemicals may etch and damage one or more materials disposed on the surface of the substrate to be cleaned in the brush cleaner 131. Accordingly, the brush cleaning process needs to be performed separately from the substrate cleaning process. In one or more embodiments, the nozzle 221 includes a first set of nozzles 221a for the substrate cleaning fluid and a second set of nozzles 221b, 221c for the brush cleaning fluid. In such embodiments, the supply conduit 226 is divided into separate supply sources (not shown) for the sources 223 of the substrate cleaning fluid and the brush cleaning fluid. According to an embodiment of the present disclosure herein, the cleaning module 108 may be configured to sequentially process each substrate 200 via two of the three or more brush cleaners 131 within the cleaning module 108 to perform a two-step cleaning process, as further discussed below. That is, after the substrate 200 has undergone a cleaning process in the first brush cleaner 131, the overhead transporter 130 then transfers the substrate 200 to the second brush cleaner 131 for further cleaning. During the cleaning sequence, after being processed in the first brush cleaner 131 for a first time period, the substrate is then transferred to the second brush cleaner 131 and then processed for a second time period. In one or more embodiments, the first time period is substantially similar to the first time period. The processes performed in the first brush cleaner 131 and the second brush cleaner 131 may include using similar fluid chemistry and mechanical processing parameters (e.g., cylindrical roller rotation speed and applied force). In some embodiments, the first brush cleaner 131 is adapted to perform a rough cleaning step to remove a substantial amount of remaining contaminants (e.g., particles, abrasive particles, chemical residues, etc.) remaining on the surface of the substrate after performing the first cleaning process in the first cleaning module, and the second brush cleaner 131 is configured to perform a cleaning process that is adapted to remove any remaining contaminants remaining from the process performed in the first brush cleaner 131. Figures 3 to 6 depict cleaning sequence patterns 300, 400, 500, 600 for periodic scrub cleaning in a CMP system. Scrub cleaners 131a, 131b, 131c may be examples of the scrub cleaner 131 described with reference to FIGS. 1 to 2D. In one or more embodiments, the CMP system is as described with reference to FIG. 1. In one or more embodiments, the patterns 300, 400, 500, 600 for periodic scrub cleaning are used in other systems where a set of scrub cleaners may be used to clean a substrate and scrub cleaning is used or desired. FIG. 3 depicts a cleaning sequence pattern 300 for periodic scrub cleaning that employs a periodic rotation of the scrub cleaning of a series of substrates among scrub cleaners 131. The time period (which may equivalently be referred to herein as a cleaning cycle) includes a set number of durations. According to pattern 300, one or more wash brushes of each scrub cleaner 131 (e.g., including tubular caps 213a, 213b) are cleaned during each duration of a certain time period. When cleaning one or more wash brushes in a scrub cleaner by rotation, for example, according to a periodic scrub cleaning process, each scrub cleaner 131 is sequentially (periodically, cyclically) unavailable for substrate cleaning operations. One or more scrub cleaners 131 that are not performing scrub cleaning operations are available for substrate (e.g., wafer) cleaning operations. An advantage of pattern 300 is that one scrub cleaner 131 is cleaned in parallel with two other scrub cleaners 131 that perform one step of a two-step cleaning process, such that one or more scrub cleaners are cleaned consistently while at least two scrub cleaners 131 are kept available for substrate cleaning operations, such that the flow of substrates being cleaned remains constant without interrupting the substrate processing sequence performed in cleaning module 108 to clean the wash brushes. In FIGS. 3 to 6, the substrates in the loaded scrub cleaners 131 are indicated by the number of the substrate, followed by whether the scrub cleaner is in the first step (A) or the second step (B) of a two-step cleaning operation. According to cleaning sequence pattern 300, during the first duration t of time period 301 1 scrub cleaner 131a is in a loaded state (e.g., loaded state 233) of performing a substrate cleaning operation on a first substrate, and scrub cleaner 131b is in a loaded state (e.g., loaded state 233) of performing a substrate cleaning operation on a second substrate. Further, during the first duration t of time period 301 1During this period, the brush cleaner 131c is in an idle state (e.g., idle state 234) of performing a brush cleaning operation to clean the washing brushes (e.g., the tubular caps 213a, 213b). In one or more embodiments, the brush cleaning operation may use a cleaning solution different from the cleaning solution used for the substrate cleaning operation. As described above, the brush cleaning process may require supplying a brush cleaning fluid to the outer surface of the washing brush and / or delivering the brush cleaning fluid to the inside of the washing brush through nozzles (e.g., nozzles 221b, 221c), such that the internally delivered brush cleaning fluid can pass through the pores in the tubular cap 213 to remove debris found on the surface of the washing brush. During the second duration t of the time period 301 2 During this period, different brush cleaners 131 may perform different cleaning operations according to the cleaning sequence pattern 300 during the first duration t 1 During this period, the brush cleaners 131b, 131c are in a loading state (e.g., loading state 233) of performing a substrate cleaning operation, and the brush cleaner 131a is in an idle state of performing a brush cleaning operation. In one or more embodiments, as part of a two-step cleaning process, the substrate cleaned in the brush cleaner 131 during the first duration (e.g., t 1 ) may be transferred to a different brush cleaner 131 during the next duration (e.g., t 2 ). The first substrate (1B) cleaned in the brush cleaner 131b during the duration t 1 is in the second step of a two-step cleaning operation (the first step of the two-step cleaning operation has been performed during the duration before the first duration t of the first time period 301 1 ). The second substrate (2A) cleaned in the brush cleaner 131a during the duration t 1 is transferred to the brush cleaner 131c (now 2B) during the second duration t 2 . During the third duration t of the time period 301 3 During this period, yet another different brush cleaner 131a may perform according to the pattern 300 during the first duration t 1 and the second duration t 2The brushing cleaning operations are performed differently during different periods. In one or more embodiments, the brushing cleaners 131b and 131c are in a loaded state for performing substrate cleaning operations (e.g., loaded state 233), and the brushing cleaner 131a is in an idle state for performing the brushing cleaning operation. In one or more embodiments, as part of a two-step cleaning process, during a second duration t 2 The third substrate (3A) being cleaned in the brushing cleaner 131b during a period can be transferred to a different brushing cleaner 131c (now 3B) during a third duration t 3 The period. During a duration t 2 The first substrate (2B) being cleaned in the brushing cleaner 131c during a period is on the second step of a two-step cleaning operation (the first step of the two-step cleaning operation has been performed in the brushing cleaner 131a during a duration t 1 The period (2A)), and the first substrate can be transferred to the next cleaning module within the cleaning module 108 (e.g., the megahertz ultrasonic cleaner 133 or the dryer 134), or at the end of the duration t 2 The period is transferred out of the cleaning module 108 (2B), and the fourth substrate (4A) is introduced into the cleaning module 108 and is cleaned in the brushing cleaner 131a during a duration t 3 The period. According to the pattern 300, the time segment 302 can be during a duration t 4 、t 5 And t 6 The period repeats the pattern of the loaded state and the idle state of the brushing cleaner 131, and the time segment 303 can be during a duration t 7 、t 8 And t 9 The period repeats the pattern of the loaded state and the idle state of the brushing cleaner 131, etc. The pattern 300 can provide improved brushing cleanliness and cleaning consistency, while allowing an increased substrate cleaning throughput, for example because at least two brushing cleaners 131 are always available for substrate cleaning operations. Figure 4 depicts a cleaning sequence pattern 400 for periodic brush cleaning, which employs a periodic rotation of brush cleaning between brush cleaners 131, where the brush cleaning operation does not switch between brush cleaners 131 for each subsequent duration. In one or more embodiments, the brush cleaning operation can be performed for at least one duration period (e.g., brush cleaner 131c performs the brush cleaning operation during t 1 ). As shown in Figure 4, during a subsequent duration (e.g., t 2 ), brush cleaner 131c is now clean but in an idle state, waiting to be loaded with a substrate during a subsequent duration (e.g., loading the third substrate (3B) into brush cleaner 131c and cleaning it in that brush cleaner 131c during duration t 3 ). In other embodiments, brush cleaner 131c can continue the cleaning operation for a duration longer than duration t 1 , for example, continuing for all or part of duration t 2 . In one or more embodiments, the cleaning duration can be a duration shorter than duration t 1 , for example, a part of duration t 1 . The time segment includes a set number of durations, which includes a specific number of durations. According to the cleaning sequence pattern 400, one or more washing brushes (e.g., cylindrical roller 228 and tubular caps 213a, 213b) of each brush cleaner 131 are cleaned during at least one duration period of the time segment of the substrate cleaning operation (e.g., the duration of one brush cleaning operation can be less than one duration, equal to one duration, more than one duration but less than two durations, or span two durations of the substrate cleaning operation). When cleaning one or more washing brushes in a brush cleaner, each brush cleaner 131 is sequentially (regularly, periodically) unavailable for the substrate cleaning operation. One or more brush cleaners 131 that are not performing the brush cleaning operation are available for substrate (e.g., wafer) cleaning operations. Thus, according to the cleaning sequence pattern 400, during the first duration t 1 of the time segment 401, brush cleaners 131a, 131b are respectively in the loading state (e.g., loading state 233) of performing the substrate cleaning operation on the second substrate (2A) and the first substrate (1B). Similarly, during the first duration t 1 During this period, the brush cleaner 131c is in an idle state (e.g., idle state 234) for performing the brush cleaning operation. In one or more embodiments, the brush cleaning operation occurs during the duration t of the time period 401 1 During. In other embodiments, the brush cleaning operation spans multiple durations, including at least the duration t of the time period 401 1 and t 2 . During the duration t 2 During, the brush cleaners 131a and 131b are again in the loading state, but the substrates (2B and 3A) being cleaned are different or are switched to different brush cleaners 131 differently than during the duration t1 The brush cleaning operation of the brush cleaner 131c can end so that substrates can be loaded into the brush cleaner 131c for the duration t of the time period 401 3 (3B) and t 4 (4B), and the brush cleaners 131b and 131c are available for substrate cleaning operations for the duration t 3 、t 4 . The brush cleaning operation of the brush cleaner 131a is performed for the duration t 3 、t 4 . In one or more embodiments, the brush cleaning operation occurs during the duration t 3 During, and the brush cleaner 131a is idle during the duration t 4 . In one or more other embodiments, the brush cleaning operation occurs during the duration t 3 、t 4 At least a portion of or across these durations. The brush cleaning operation of the brush cleaner 131a can end so that substrates 6A and 7A are loaded into the brush cleaner 131a for the duration t of the time period 401 5 、t 6 ,and the brush cleaners 131a and 131c are available for substrate cleaning operations for the duration t 5 、t 6 The brushing operation of the brush cleaner 131b can be performed for a duration t 5 , t 6 (e.g., a portion of the duration t 5 or spanning t 5 , t 6 ). According to the cleaning sequence pattern 400, the time period 401 can repeat the pattern of the loading and idle states of the brush cleaner 131 during subsequent time periods (including the time period 402, which includes the duration t 7 , t 8 , t 9 , t 10 and so on). The cleaning sequence pattern 400 can provide an extended brushing operation time, a lower brushing frequency, and improved brushing efficacy, such as in cases where it is necessary to extend the time between brushing operations and the brushing operation can be used for a longer time. FIG. 5 depicts a cleaning sequence pattern 500 for periodic brushing, which employs a periodic rotation of the brushing between the brush cleaners 131, where the brushing process does not occur during each duration period. The time period includes a set number of durations, including a specific number of durations. According to the cleaning sequence pattern 500, one or more washing brushes (e.g., the cylindrical roller 228 and the tubular caps 213a, 213b) of each brush cleaner 131 are cleaned for a certain time period, and the brush cleaner 131 is not cleaned during other duration periods. When one or more washing brushes are cleaned in the brush cleaner 13, each brush cleaner 131 is sequentially (regularly, periodically) unavailable for the substrate cleaning operation. One or more brush cleaners 131 that are not performing the brushing operation are available for the substrate (e.g., wafer) cleaning operation. In one or more embodiments, the durations for cleaning the washing brushes in a certain time period can be separated by one or more durations such that all the brush cleaners are available for cleaning the substrate therein during one or more duration periods of the time period. The duration for a brush cleaner 131 to clean one of the washing brushes can be spaced apart, or two or more brush cleaners can perform the substrate cleaning operation during a single duration period of the time period. According to the cleaning sequence pattern 500, each brush cleaner 131 of the CMP system 100 performs a substrate cleaning operation during a time period 501, which includes eight durations. Brush cleaners 131a and 131b perform the brush cleaning operation during the same duration, and brush cleaners 131c and 131d perform the brush cleaning operation during the same duration that is different from the duration of brush cleaners 131a and 131b. Although pattern 500 illustrates a time period that includes eight durations, there are two sets of three durations without a brush cleaning operation (e.g., t 1 、t 5 ) between brush cleaning operations (e.g., t 2 、t 3 、t 4 、t 6 、t 7 、t 8 ), and different numbers and arrangements of brush cleaning operations can also be used, which is consistent with the disclosure herein. For example, in one or more embodiments, the time period 501 has three durations, and one of these durations does not perform a brush cleaning operation. In other embodiments, the time period 501 has a total of four durations (e.g., t 1 、t 2 、t 3 、t 4 ), and there is one duration without a brush cleaning operation (e.g., t 1 、t 3 ) between each brush cleaning operation (e.g., t 2 、t 4 ). The cleaning sequence pattern 500 illustrates that during the first duration t 1During this period, the brush cleaners 131a and 131b are in the loaded state (e.g., loaded state 233) where they start their two-stage cleaning operations for cleaning the first substrate (1A) and the substrate (13B) respectively during the previous time period. Similarly, during the first duration t of the time period 501 1 During this period, the brush cleaners 131c and 131d are in the idle state (e.g., idle state 234) where they perform the brush cleaning operation. During the duration t 2 During this period, all the brush cleaners 131a, 131b, 131c, and 131d are again in the loaded state, but the substrates being cleaned are different or are switched differently to different brush cleaners 131 (substrates 1B and 14B, which are from the previous time period) than during the duration t 1 period, and the third and fourth substrates (2A and 3A) are respectively loaded in the brush cleaners 131A and 131B for substrate cleaning operations. During the duration t 2 During this period, no brush cleaning operation is performed on the brush cleaners 131a, 131b, 131c, and 131d. During the third duration t of the time period 501 3 and the fourth duration t 4 During this period, the brush cleaners 131a, 131b, 131c, and 131d are in the loaded state (e.g., loaded state 233) where they perform substrate cleaning operations. During the fifth duration t of the time period 501 5 During this period, the brush cleaners 131c and 131d are in the loaded state (e.g., loaded state 233) where they perform substrate cleaning operations on the seventh substrate (7B) and the eighth substrate (8A), and the brush cleaners 131a and 131b are in the idle state (e.g., idle state 234) where they perform brush cleaning operations. During the sixth duration t of the time period 501 6 During the seventh duration t 7 and the eighth duration t 8 During this period, all the brush cleaners 131a, 131b, 131c, and 131d are in the loaded state (e.g., loaded state 233) where they perform substrate cleaning operations, and no brush cleaning operation is being performed on the brush cleaners 131a, 131b, 131c, and 131d. The cleaning sequence pattern 500 can provide an increased substrate cleaning throughput, for example, reducing the frequency of brush cleaning when it is desired and within tolerance. Figure 6 depicts a cleaning sequence pattern 600 for periodic brush cleaning that employs a rotation of brush cleaning among brush cleaners 131, where different brush cleaners among the brush cleaners 131 use different durations for brush cleaning. In one or more embodiments, the different time segments include different numbers of durations. According to pattern 600, time segment 601 includes four durations, and time segment 602 includes five durations. During time segment 601, brush cleaner 131a performs brush cleaning operations across two durations, including brush cleaning operations on a first substrate (1B) that was cleaned in the first step of a two-step cleaning process in a previous time segment and a second substrate (2A) that was loaded and cleaned in the first duration t 1 and performing the brush cleaning operation for a second duration t 2 that includes a second substrate (2B) that was cleaned in the second step of the two-step cleaning process and a third substrate (3A) that was loaded and cleaned in the first step of the two-step cleaning process. During the remaining durations of time segment 601, brush cleaner 131b performs a brush cleaning operation across one duration t 3 and cleaning substrates 4A and 3B in brush cleaners 131a and 131c respectively within the duration t 3 . Brush cleaner 131c performs a brush cleaning operation across one duration t 4 and cleaning substrates 4B and 5A in brush cleaners 131b and 131a respectively within the duration t 4 . During time segment 602, brush cleaner 131a performs brush cleaning operations across two durations t 5 、t 6 . Brush cleaner 131b performs brush cleaning operations across two durations t 7 、t 8 . Brush cleaner 131c performs a brush cleaning operation across one duration t 9 . In one or more embodiments, in a time period following time period 601, the first time period has four durations (e.g., 601) and alternates with a second time period having five durations (e.g., 602). Thus, brush cleaner 131a is cleaned for two durations per time period, brush cleaner 131c is cleaned for one duration per time period, and brush cleaner 131b is cleaned for a duration that alternates between one duration and two durations. Cleaning sequence pattern 600 can provide increased configurability and flexibility in the system, such as in cases where different numbers of cleaning steps, cleaning chemicals, or brush configurations are used. In one or more embodiments, when performing a brush cleaning operation to clean the scrubbing brush, one or more of the patterns 300, 400, 500, 600 can use a "virtual wafer" (which can also be referred to as a "virtual substrate"). The "virtual wafer" can circulate through brush cleaner 131 separately or in parallel from the "product wafers" being cleaned in the other brush cleaners in brush cleaner 131. The "virtual wafer" is stored in a queue in CMP system 100. In one or more embodiments, the "virtual wafer" has substantially the same size and shape as the "product wafer" and is compatible with the brush cleaning fluid. In one or more embodiments, in CMP system 100, used old "virtual wafers" are periodically (e.g., after a certain number of cleaning cycles, manually or automatically) removed and replaced with new "virtual wafers". In one or more embodiments, the "virtual wafer" is used and replaces the adjustment device 260 (substituting for the functionality of adjustment device 260). In other embodiments, in addition to using adjustment device 260, the "virtual wafer" is also used. In some embodiments, the use of the "virtual wafer" can simplify the maintenance and operation of CMP system 100 because the "virtual wafer" is easier to replace than adjustment device 260. Although patterns 300, 400, 500, 600 depict the use of three or four brush cleaners 131, more or fewer numbers of brush cleaners 131 can be used according to the disclosure herein. In one or more embodiments, two brush cleaners 131a, 131b are used, where each brush cleaner alternates between being available for substrate cleaning operations in a first duration and performing a brush cleaning operation in a second duration, such that the brush cleaner 131 can be used for substrate cleaning operations for a given duration. In one or more other embodiments, brush cleaner 131a performs a brush cleaning operation during a set of durations that includes every fourth duration, while brush cleaner 131b performs a brush cleaning operation during a different set of durations that includes every fourth duration. In one or more embodiments, four or more brush cleaners 131 are used, where different brush cleaners perform brush cleaning operations during different duration periods. In one embodiment, a three-step cleaning process is used with four brush cleaners 131 such that each brush cleaner performs a brush cleaning operation every fourth duration and three brush cleaners are available during a given duration period. FIG. 7 is a diagram illustrating a method 700 of operating a CMP system according to certain embodiments. It should be noted that the CMP system 100 described in the following examples is for illustrative purposes only. Operation 705 includes rotating one or more first cleaning brushes in a first brush cleaner of the CMP system during a first duration period of a cleaning cycle while contacting the one or more first cleaning brushes with a first substrate. In one or more embodiments, the CMP system 100 may include a first brush cleaner 131 (e.g., brush cleaner 131a), the one or more first cleaning brushes may be an example of a pair of tubular caps 213a, 213b, and the first substrate may be an example of substrate 200. Operation 710 includes performing a cleaning operation on one or more second cleaning brushes in a second brush cleaner of the CMP system while rotating during the first duration. In one or more embodiments, the CMP system 100 may include a second brush cleaner 131 (e.g., brush cleaner 131b), the one or more second cleaning brushes may be an example of a pair of tubular caps 213a, 213b, and the second substrate may be an example of substrate 200. Operation 715 includes performing a cleaning operation on the one or more first cleaning brushes in the first brush cleaner during a second duration period of the cleaning cycle. Operation 720 includes rotating the one or more second cleaning brushes while performing a cleaning operation during the second duration while contacting the one or more second cleaning brushes with a second substrate. Additionally, in some embodiments of method 700, operations 705 and 710 are performed substantially concurrently (simultaneously), and operations 715 and 720 are performed substantially concurrently (simultaneously). In some embodiments of method 700, operation 705 is initiated before initiating operation 710. In some embodiments of method 700, operation 710 is initiated before initiating operation 705. In some embodiments of method 700, operation 720 is initiated before initiating operation 715. In some embodiments of method 700, operation 715 is initiated before initiating operation 720. When introducing elements of the present disclosure or exemplary aspects or embodiments thereof, the articles "a", "an", "the", and "said" are intended to mean that there is one or more elements. The terms "comprising", "including", and "having" are intended to be inclusive and mean that there may be additional elements in addition to the listed elements. Although 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, and the scope of the present disclosure is determined by the appended claims. 1A: Substrate 1B: Substrate 2A: Substrate 2B: Substrate 2D: Substrate 3A: Substrate 3B: Substrate 4A: Substrate 4B: Substrate 5A: Substrate 5B: Substrate 6A: Substrate 6B: Substrate 7A: Substrate 7B: Substrate 8A: Substrate 8B: Substrate 9A: Substrate 9B: Substrate 10A: Substrate 10B: Substrate 11A: Substrate 11B: Substrate 12A: Substrate 12B: Substrate 13A: Substrate 13B: Substrate 14A: Substrate 14B: Substrate 100: CMP system 102: Factory interface module 104: Input module 106: Polishing module 108: Cleaning module 110: Substrate cassette 111: Housing 112: Factory interface robot 114: Transfer robot 116: Transfer station 118: Polishing station 120: Polishing pad 122: Dispensing arm 123: Regulator head 124: Carrier head 129: Pre-cleaning module 130: Overhead conveyor 131: Brush cleaner 131a: Brush cleaner 131b: Brush cleaner 131c: Brush cleaner 131d: Brush cleaner 133: Megahertz ultrasonic cleaner 134: Dryer 140: System controller 142: Central processing unit (CPU) 144: Memory 146: Support circuit 200: Substrate 205: Tank 210: Link 211: Washing device 213a: Tubular lid 213b: Tubular lid 215: Knot 217: Valley 218: Pivot mount 221: Nozzle 221a: Nozzle 221b: Nozzle 221c: Nozzle 221d: Nozzle 223: Source 225: First support 226: Supply pipe 228: Cylindrical roller 230: Second support 233: Loading state 234: Idle state 235: Actuator 240: Base 244: Drive motor 245: Actuator 247: Rotating device 249: Support roller 249a: Roller 249b: Roller 249c: Roller 260: Adjusting device 270: Support member 300: Cleaning sequence mode 301: Time period 302: Time period 303: Time period 400: Cleaning sequence mode 401: Time period 402: Time period 500: Cleaning sequence mode 501: Time period 600: Cleaning sequence mode 601: Time period 602: Time period 700: Method 705: Operation 710: Operation 715: Operation 720: Operation A': Axis A'': Axis T 1 : First duration T 2 : Second duration T 3 : Third duration T 4 : Fourth duration T 5 : Fifth duration T 6 : Sixth duration T 7 : Seventh duration T 8 : Eighth duration T 9 : Ninth duration T 10 : Tenth duration To be able to understand the above features of the present disclosure in detail, the present disclosure briefly summarized above can be described more specifically with reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments and should not be regarded as limiting the scope of the present disclosure, because the present disclosure may allow other equally effective embodiments. FIG. 1 is a schematic top view of a chemical mechanical polishing (CMP) system according to an embodiment discussed herein. FIG. 2A is a perspective view of an example of a brush cleaner utilized in the CMP processing system of FIG. 1 according to one or more embodiments. FIG. 2B is a top cross-sectional view of the brush cleaner of FIG. 2A according to one or more embodiments. FIGS. 2C to 2D depict perspective views of a washing device performing periodic brush cleaning according to certain embodiments. FIGS. 3 to 6 depict cleaning sequence patterns for periodic brush cleaning in a CMP system according to certain embodiments. FIG. 7 is a diagram illustrating a method of operating a CMP system according to certain embodiments. To facilitate understanding, wherever possible, the same reference numerals are used to denote common elements in the accompanying drawings. It is contemplated that elements and features of one embodiment can be beneficially incorporated into other embodiments without further recitation. Domestic deposit information (please note in the order of deposit institution, date, number) None Foreign deposit information (please note in the order of deposit country, institution, date, number) None 1B: Substrate 2A: Substrate 2B: Substrate 3A: Substrate 3B: Substrate 4A: Substrate 4B: Substrate 5A: Substrate 5B: Substrate 6A: Substrate 6B: Substrate 7A: Substrate 7B: Substrate 8A: Substrate 8B: Substrate 9A: Substrate 9B: Substrate 10A: Substrate 10B: Substrate 11A: Substrate 131a: Brush cleaner 131b: Brush cleaner 131c: Brush cleaner 300: Cleaning sequence pattern 301: Time period 302: Time period 303: Time period T 1 : First duration T 2 : Second duration T 3 : Third duration T 4 : Fourth duration T 5 : Fifth duration T 6 : Sixth duration T 7 : Seventh duration T 8 : Eighth duration T 9 : Ninth duration T 10 : Tenth duration

Claims

1. A method of operating a chemical mechanical polishing (CMP) system, comprising the steps of: rotating one or more first scrubbing brushes disposed in a first tank in a first brush cleaner of the CMP system during a first duration of a cleaning cycle, while simultaneously contacting one or more surfaces of a vertical first substrate disposed in the first tank, and supplying a substrate cleaning fluid to the first substrate from a supply conduit configured to deliver the substrate cleaning fluid to the first substrate from a source; and simultaneously performing a cleaning operation on one or more second scrubbing brushes disposed in a second tank in a second brush cleaner of the CMP system during the first duration of the rotation, wherein the cleaning operation comprises the steps of: delivering a brush cleaning fluid from the supply conduit to the second brushes, wherein no substrate is disposed in the second tank, the supply conduit configured to receive the brush cleaning fluid from the source; During a second duration of the cleaning cycle, a cleaning operation is performed on the first brush cleaner for the first one or more washing brushes, wherein the cleaning operation includes the following steps: delivering brush cleaning fluid to the first one or more washing brushes, with no substrate disposed in the first tank; rotating the second one or more washing brushes in a second brush cleaner of the CMP system while performing the cleaning operation during the second duration, simultaneously bringing the second one or more washing brushes into contact with a vertical second substrate disposed in the second tank, and providing substrate cleaning fluid to the second substrate; and rotating a third one or more washing brushes disposed in a third tank while performing the cleaning operation during the second duration of the CMP system, simultaneously bringing the third one or more washing brushes into contact with the vertical first substrate disposed in the first tank, and providing substrate cleaning fluid to the first substrate.

2. The method as described in claim 1, further comprising the steps of: rotating the third one or more washing brushes in the third brush cleaner during the first duration, while simultaneously bringing the third one or more washing brushes into contact with a third substrate disposed in the third tank, and providing substrate cleaning fluid to the one or more surfaces of the third substrate.

3. The method as described in claim 1, further comprising the steps of: rotating the first one or more washing brushes in the first brush cleaner during a third duration of the cleaning cycle, while simultaneously bringing the first one or more washing brushes into contact with a fourth substrate; and rotating the second one or more washing brushes in the second brush cleaner during a fourth duration, while simultaneously bringing the second one or more washing brushes into contact with the fourth substrate.

4. The method as described in claim 1, wherein: The brush cleaning fluid comprises a chemical composition different from that of the substrate cleaning fluid, and the brush cleaning fluid is configured to clean and remove debris from the first or more washing surfaces of the washing brushes.

5. The method as described in request item 1, wherein: During the first duration, a first set of nozzles of the first brush cleaner is used to guide the substrate cleaning fluid to the first substrate; and during the second duration, when the one or more washing brushes are not in contact with the substrate, a second set of nozzles of the first brush cleaner is used to guide the brush cleaning fluid to the first one or more washing brushes.

6. The method as described in claim 1, further comprising the steps of: rotating the first one or more washing brushes during the second duration of the rotation, while simultaneously bringing at least one adjusting rod into contact with one or more of the first one or more washing brushes.

7. The method as described in claim 1, wherein the cleaning cycle is periodic according to a first time period.

8. A chemical mechanical polishing (CMP) system, comprising: A first brush cleaner includes: a first tank; and one or more first washing brushes disposed in the first tank; a second brush cleaner includes: a second tank; and one or more second washing brushes disposed in the second tank; and a system controller configured to simultaneously control the first brush cleaner and the second brush cleaner to: rotate the one or more first washing brushes during a first duration of a cleaning cycle, while simultaneously contacting the one or more first washing brushes with a vertical first substrate disposed in the first tank, and supplying substrate cleaning fluid from a supply conduit to the first substrate, the supply conduit being configured to deliver the substrate cleaning fluid from a source to the first substrate; and performing a cleaning operation during the first duration of the rotation, the cleaning operation including delivering brush cleaning fluid from the supply conduit to the second or more washing brushes, at which time no substrate is disposed in the second tank, the supply conduit being configured to receive the brush cleaning fluid from the source; A cleaning operation is performed during a second duration of the cleaning cycle, the cleaning operation including delivering the brush cleaning fluid to the first one or more washing brushes, with no substrate disposed in the first tank; and rotating the second one or more washing brushes while performing the cleaning operation during the second duration, thereby bringing the second one or more washing brushes into contact with a vertical second substrate disposed in the second tank, and providing substrate cleaning fluid to the second substrate.

9. The CMP system as described in claim 8, further comprising: A third brush cleaner, comprising one or more third washing brushes disposed in a third tank, wherein the system controller is further configured to rotate one or more third washing brushes in the third brush cleaner during the first duration of time while performing the cleaning operation, and simultaneously to contact the one or more third washing brushes with a third substrate disposed in the third tank and to provide cleaning fluid to one or more surfaces of the third substrate.

10. The CMP system as claimed in claim 8, wherein the system controller is configured to: rotate the first one or more washing brushes during a third duration of the cleaning cycle, while simultaneously bringing the first one or more washing brushes into contact with the first substrate or a fourth substrate; and rotate the second one or more washing brushes during the third duration, while simultaneously bringing the second one or more washing brushes into contact with the second substrate or a fifth substrate.

11. The CMP system as claimed in claim 8, wherein the brush cleaning fluid contains a chemical composition different from that of the substrate cleaning fluid, and the brush cleaning fluid is configured to clean and remove debris from the first or more washing surfaces of the washing brush.

12. The CMP system as claimed in claim 8, wherein the system controller is configured to rotate the first one or more washing brushes during the second duration of rotation, while simultaneously bringing at least one adjusting rod into contact with one or more of the first one or more washing brushes.

13. The CMP system as claimed in claim 8, wherein the source includes a substrate cleaning fluid source and a separate brush cleaning fluid source, wherein each of the first brush cleaner and the second brush cleaner further includes: A first set of nozzles configured to spray substrate cleaning fluid from the substrate cleaning fluid source; and a second set of nozzles configured to spray brush cleaning fluid from the brush cleaning fluid source.

14. A chemical mechanical polishing (CMP) system, comprising: A first brush cleaner accommodating one or more first washing brushes disposed in a first tank; a second brush cleaner accommodating one or more second washing brushes disposed in a second tank; and a computer-readable medium that can read media storing instructions, which, when executed by a processor of the CMP system, cause the CMP system to: rotate the one or more first washing brushes during a first duration of a cleaning cycle, while simultaneously bringing the one or more first washing brushes into contact with a first substrate disposed vertically in the first tank; perform a cleaning operation on the one or more second washing brushes during the rotation during the first duration, while no substrate is disposed in the second tank; perform the cleaning operation on the one or more first washing brushes during a second duration of the cleaning cycle, while no substrate is disposed in the first tank; and rotate the one or more second washing brushes during the cleaning operation during the second duration, while simultaneously bringing the one or more second washing brushes into contact with a second substrate disposed vertically in the second tank.

15. The CMP system as described in claim 14, further comprising: A third brush cleaner, accommodating one or more third washing brushes disposed in a third tank, wherein when the processor executes the instructions, it further causes the third or more washing brushes to alternately perform the cleaning operation on one or more third washing brushes in the third brush cleaner during the first duration of rotation and while performing the cleaning operation, and at the same time the third or more washing brushes contact a third substrate disposed in a third tank.

16. The CMP system as claimed in claim 14, wherein the instructions further cause the CMP system to: rotate the first one or more washing brushes in the first brush cleaner during a third duration of the cleaning cycle, while simultaneously contacting the first one or more washing brushes with the first substrate or a fourth substrate; and rotate the second one or more washing brushes in the second brush cleaner during the third duration, while simultaneously contacting the second one or more washing brushes with the second substrate or a fifth substrate.

17. The CMP system as claimed in claim 14, wherein the instructions further cause the CMP system to: guide a substrate cleaning fluid to the first substrate while rotating the first one or more washing brushes during the first duration; and guide a brush cleaning fluid to the first one or more washing brushes when the one or more washing brushes are not in contact with the substrate during the second duration.

18. The CMP system as claimed in claim 14, wherein the instructions further cause the CMP system to: rotate the first one or more washing brushes during the second duration of rotation, while simultaneously bringing at least one adjusting rod into contact with one or more of the first one or more washing brushes.

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