Cleaning unit in chemical mechanical polishing system

Abstract

A brush cleaning system for cleaning a substrate includes a tank and a cylindrical roller disposed in the tank for cleaning the substrate. The cleaning system also includes a substrate holder for retaining the substrate in a vertical orientation and rotating the substrate. A movable substrate support is used to support the substrate in the tank.

Description

44025320W001 CLEANING UNIT IN CHEMICAL MECHANICAL POLISHING SYSTEM BACKGROUNDField

[0001] Embodiments of the present invention generally relate to electronic device manufacturing, and in particular, to chemical mechanical polishing (CMP) systems and methods used in a semiconductor device manufacturing processes.Description of the Related Art

[0002] During chemical mechanical polishing (CMP) processing, scattered particles, such as Cu, Ta, W, TaN, or Ti, may accumulate on both the front surface and back surface of a substrate. To properly remove the scattered particles, most post-CMP cleaning processes include physical cleaning as one of cleaning steps. Typically, the physical cleaning methods largely consist of physically removing excess metals using scrubbing brushes.

[0003] CMP systems may include a post-CMP cleaning station for cleaning the substrate after CMP processing. The cleaning station may use scrubbing brushes to remove particles by directly contacting the brush with the substrate surface. Typical cleaning stations consist of one brush on either side of the substrate surface. The brushes are spaced apart when the substrate is received or removed from the scrubbing assembly. The brushes are brought into contact with the substrate during cleaning.

[0004] In some instances, the two brushes are arranged in a toe-in configuration with respect to the substrate such that the brushes are not parallel with the substrate. This arrangement leads to uneven wear on the brushes, thereby potentially requiring more frequent maintenance of one or both brushes. Usage of two brushes also increases the consumables of the brush box.

[0005] Also, substrate idlers are sometimes used to determine the number of rotations of the substrate during brush cleaning. However, the substrate idler may report the incorrect rotations or speed due to substrate slippage.

[0006] There is, therefore, a need for an improved brush cleaning unit that can reduce operating costs.44025320W001 SUMMARY

[0007] In some embodiments, a brush cleaning system for cleaning a substrate includes a tank and a cylindrical roller disposed in the tank for cleaning the substrate. The cleaning system also includes a substrate holder for retaining the substrate in a vertical orientation and rotating the substrate. A movable substrate support is used to support the substrate in the tank.

[0008] In some embodiments, a method of cleaning a substrate includes supporting a substrate in a vertical orientation on a substrate support and retaining the substrate using a substrate holder. The method also includes rotating the substrate holder to rotate the substrate and cleaning the substrate using a cylindrical roller.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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 exemplary embodiments of the present disclosure and are therefore not to be considered limiting of its scope, as the present disclosure may admit to other equally effective embodiments.

[0010] Figure 1 is a schematic view of a chemical mechanical polishing (CMP) system, according to certain embodiments.

[0011] Figure 2 is an isometric view of an exemplary brush cleaner which may be utilized in the CMP system of Figure 1 , according to some embodiments.

[0012] Figure 3 is a side view of the brush cleaner of Figure 1 , according to some embodiments.

[0013] Figures 4A-4J illustrate sequential operation of a method of cleaning a substrate, according to some embodiments.

[0014] Figure 5 shows another exemplary brush cleaner which may be utilized in the CMP system of Figure 1 , according to some embodiments.44025320W001

[0015] Figure 6 shows an exemplary substrate holder which may be utilized in the brush holder of Figure 2, according to some embodiments

[0016] Figure 7 shows the substrate holder of Figure 6 retaining a substrate.

[0017] 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.DETAILED DESCRIPTION

[0018] Embodiments herein generally relate to chemical mechanical polishing (CMP) systems, and in particular, to cleaning systems used with CMP systems and methods related thereto.

[0019] In one embodiment, a brush cleaning system for cleaning a substrate includes a cylindrical roller disposed in the tank for cleaning the substrate. The cleaning system also includes a substrate holder for retaining the substrate in a vertical orientation and rotating the substrate. A movable substrate support is used to support the substrate in the tank. The use of a single cylindrical roller beneficially provides a low maintenance cleaning system for cleaning the substrate. The substrate is advantageously rotated using a substrate holder instead of drive rollers engaging the edge of the substrate. Use of the substrate holder to rotate the substrate also eliminates the need to implement a toe-in alignment for the cylindrical roller.

[0020] Figure 1 illustrates a schematic top view of a chemical mechanical polishing (CMP) system 100. The CMP system 100 generally includes a factory interface module 102, a polishing module 106, and a cleaning module 108. These major components are generally disposed within the CMP system 100.

[0021] The factory interface module 102 includes a support to hold a plurality of cassettes 110 and one or more interface robots 112. The interface robot 112 generally provides the range of motion required to transfer substrates between the cassettes 110 and one or more of the other modules of the CMP system 100.44025320W001

[0022] Unprocessed substrates are generally transferred from the cassettes 110 to an input module 104 by the interface robot 112. The input module 104 generally facilitates transfer of a substrate between the interface robot 112 and a transfer robot 114. The transfer robot 114 transfers the substrate between the input module 104 and the polishing module 106.

[0023] The polishing module 106 generally comprises 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 accept the substrate from the transfer robot 114. The transfer station 116 transfers the substrate to at least one carrier head 124 of a polishing station 118 that retains the substrate during polishing.

[0024] The polishing stations 118 each includes a rotatable disk-shaped platen on which a polishing pad 120 is situated. The platen is operable to rotate about an axis. The polishing pad 120 can be a two-layer polishing pad with an outer polishing layer and a softer backing layer. The polishing stations 118 each further includes a dispensing arm 122, to dispense a polishing liquid, e.g., an abrasive slurry, onto the polishing pad 120. In the abrasive slurry, the abrasive particles can be silicon oxide, but some polishing processes use cerium oxide abrasive particles. Each polishing station 118 can also include a conditioner head 123 to maintain the polishing pad 120 at a consistent surface roughness.

[0025] The polishing stations 118 each includes at least one carrier head 124. The at least one carrier head 124 is operable to hold a substrate against the polishing pad 120 during a polishing operation. Following the polishing operation performed on a substrate, the at least one carrier head 124 transfers the substrate back to the transfer station 116.

[0026] The transfer robot 114 then removes the substrate from the polishing module 106 through an opening connecting the polishing module 106 with the remainder of the CMP system 100. The transfer robot 114 removes the substrate in a horizontal orientation from the polishing module 106 and transfers the substrate to the cleaning module 108.44025320W001

[0027] The cleaning module 108 generally includes one or more cleaning devices that can operate independently or in concert. For example, the cleaning module 108 can include, from top to bottom in Figure 1, a resist removal module 128, an input module 129, one or more brush modules 131, 132, a megasonic cleaner 133, and a drying module 134. In some embodiments, a buffing pad module can replace or add to one or more of the brush modules 131, 132. Other possible cleaning devices include chemical spin cleaners and jet spray cleaners (not shown). A transport system, e.g., an overhead conveyor 130 that supports robot arms, can walk or run the substrate from cleaning device to cleaning device. In one example, after cleaning in the brush pad module 131, 132, the conveyor 130 can transfer the substrate to the megasonic cleaner 133 in which high frequency vibrations produce controlled cavitation in a cleaning liquid to clean the substrate. Alternatively, the megasonic cleaner 133 can be positioned before the brush module 131, 132. A final rinse can be performed in a rinsing module before being transferred to the drying module 134.

[0028] The one or more brush modules 131, 132, which may be represented by the brush cleaner described further below in Figures 2 and 3, directly contacts the substrate. In some examples, one or more brush modules 131, 132 may be a brush scrubbing module that uses a rotating brush to scrub the substrate surface. Briefly, the one or more brush modules 131 , 132 are devices in which the substrate can be placed and the surfaces of the substrate are contacted with a rotating brush to remove any remaining particulates. In some embodiments, a cleaning solution is applied to the substrate during the scrubbing process. The cleaning solution concurrently dissolves and weakens the bonds between particles and the substrate surface. Following dislodgment of contaminants from the substrate surface, the cleaning solution flushes the contaminants from the substrate surface.

[0029] The CMP system 100 includes a controller 160, which generally includes one or more processors, memory, and support circuits. The one or more processors may include a central processing unit (CPU) and may be one of any form of a general purpose processor that can be used in an industrial setting. The memory, or non-transitory computer-readable medium, is accessible by the one or more processors and may be one or more of memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local44025320W001 or remote. The support circuits are coupled to the one or more processors and may comprise cache, clock circuits, input / output subsystems, power supplies, and the like. The various methods disclosed herein may generally be implemented under the control of the one or more processors by the one or more processors executing computer instruction code stored in the memory as, for example, a software routine. When the computer instruction code is executed by the one or more processors, the one or more processors controls the CMP system 100 to perform processes in accordance with the various methods disclosed herein.

[0030] Figure 2 is an isometric view of an exemplary a brush cleaner 200, which may be utilized as one or more brush modules 131, 132 in the CMP system 100 as described above. A lid portion of the brush cleaner 200, which includes a door, has been removed from Figure 2 for ease of discussion. Figure 3 is a cross-sectional side view of the brush cleaner 200 of Figure 2. Figures 2 and 3 show the cylindrical roller 228 in a processing position, in which the cylindrical roller 228 is closed (e.g. , pressed) against major surfaces of the substrate 201. In some embodiments, the substrate 201 is a semiconductor wafer. The brush cleaner 200 shown in Figures 2-3 can be a scrubber brush box-type vertical cleaner. As shown, the example brush cleaner 200 includes a tank 205 for receiving the substrate 201 for cleaning.

[0031] The brush cleaner 200 includes a scrubbing device, such as a cylindrical roller 228, located inside the tank 205. In one embodiment, the cylindrical roller 228 is supported by movable mounting 219 (e.g., pivotal mounting) adapted to move the cylindrical roller 228 into and out of contact with the substrate 201 , as represented by direction arrow 191 in Figure 2. For example, the movable mounting 219 can move the cylindrical roller 228 toward the substrate 201 to an extended position and close against the substrate 201 as shown in Figure 3, or move the roller 228 away from the substrate 201 to a retracted position to allow insertion and / or removal of the substrate 201 from the brush cleaner 200. The cylindrical roller 228 is coupled to and controlled by the controller 160, which may control movement of the roller 228 toward or away from the substrate 201.

[0032] The cylindrical roller 228 may be coupled to a drive motor 229 for rotating the cylindrical roller 228. The controller 160 may control the rotational speed or rotational direction of the roller 228. In one example, the roller 228 is rotated in a44025320W001 clockwise direction 192, as shown in Figure 2. In some embodiments, the cylindrical roller 228 includes a plurality of raised nodules across its outer surface and a plurality of valleys located among the nodules.

[0033] The brush cleaner 200 includes a substrate holder 210 for retaining the substrate 201 in a vertical orientation. In some embodiments, the substrate holder 210 includes a retaining device coupled to a drive shaft 218. In some examples, the retaining device is a retaining chuck, such as a vacuum chuck 215 or an electrostatic chuck.

[0034] In one embodiment, the substrate holder 210 retains the substrate 201 using a vacuum chuck 215. The upper surface of the vacuum chuck 215 includes a plurality of holes 212 in fluid communication with a vacuum pump 214 via a vacuum conduit 213 disposed within the drive shaft 218. For example, pneumatic gas (such as air or nitrogen) and / or liquid is pumped away from the plurality of holes 212 at the upper surface to create a negative pressure behind the substrate 201. The atmospheric pressure on the other (“front”) side of the substrate 201 retains the substrate 201 against the chuck 215. In some examples, the outer diameter of the upper surface of the vacuum chuck 215 is smaller than the outer diameter of the substrate 201. In this respect, the backside of the substrate 201 includes an outer ring portion 237 that is not obstructed by the vacuum chuck 215. To release the substrate 201 , pneumatic air is pumped through the plurality of holes 212 toward the upper surface of the vacuum chuck 215.

[0035] In some embodiments, liquid is used to release the substrate 201 from the vacuum chuck 215. For example, liquid, such as water or other suitable cleaning fluid, can be supplied from a liquid source 224 via a conduit 223 disposed within the drive shaft 218 to the top surface of the vacuum chuck 215 to release the substrate 201. The liquid may advantageously clean the backside of the substrate 201 as the substrate 201 is being released.

[0036] Additionally or alternatively, the substrate 201 is retained by the substrate holder 210 using an electrostatic chuck. The electrostatic chuck typically includes at least a dielectric material that surrounds an electrode (not shown) located on an upper surface of the electrostatic chuck or formed within the electrostatic chuck. The44025320W001 dielectric portion of the chuck electrically insulates the chuck electrode from the substrate 201 and from the remainder of the substrate holder 210. In one embodiment, a diameter of the electrostatic chuck is smaller than the diameter of the substrate 201. Thus, the substrate 201 entirely covers the electrostatic chuck and shields the electrostatic chuck from exposure to potentially corrosive or damaging substances utilized during processing of the substrate 201.

[0037] The retained substrate 201 can be rotated by rotating the drive shaft 218. In one example, a motor 203 turns the drive shaft 218 to rotate the vacuum chuck 215. The substrate holder 210 is coupled to and controlled by the controller 160, which may control the rotational speed or rotational direction of the drive shaft 218. In one example, the drive shaft 218 is rotated in a clockwise direction 196, as shown in Figure 2. The controller 160 may also control movement of the substrate holder 210 toward or away from the substrate 201. For example, the controller 160 can operate the motor 203 to move the vacuum chuck 215 toward the substrate 201 to an extended position for engagement with the substrate 201. The controller 160 can also move the vacuum chuck 215 away from the substrate 201 to a retracted position after disengagement with the substrate 201 , as represented by direction arrow 195 in Figure 2.

[0038] In some embodiments, a retaining film 222 may be disposed on the upper surface of the vacuum chuck 215 for engaging the substrate 201. The surface of the retaining film 222 is configured to frictionally retain the substrate 201 during processing. In some embodiments, the retaining film 222 is configured to retain a substrate 201 that weighs less than 2,000 grams in a vertical orientation during processing. Exemplary retaining films include a low durometer rubber, a polyvinyl alcohol film, and a polyurethane film. In some examples, the retaining film 222 is configured to retain the substrate 201 while the substrate 201 is rotated between 10 rpm and 70 rpm, such as between 30 rpm and 60 rpm.

[0039] The brush cleaner 200 also includes one or more substrate supports 250 adapted to support the substrate 201 during insertion or removal of the substrate 201 from the brush cleaner 200, as shown in Figure 3. It is contemplated the substrate support 250 may be any support adapted to retain the substrate 201 in a vertical orientation when not supported by the substrate holder 210. In one example, two substrate supports 250 can be disposed below the substrate 201 and spaced apart for44025320W001 supporting the substrate 201 via contact with the edge of the substrate 201. The substrate supports 250 are positioned to present the substrate 201 for engagement with the substrate holder 210. In one example, each of the substrate supports 250 include a groove 253 adapted to vertically support the substrate 201. In one embodiment, the substrate support 250 is a cylindrically shaped support. In one example, the substrate support 250 is one or more support rollers 251 such as two support rollers 251. In another example, the substrate support 250 is a substrate stand having a flat surface and an optional groove 253 to support the bottom edge of the substrate 201. In some embodiments, the substrate supports 250 are made from a plastic material or other polymeric material.

[0040] In some embodiments, the substrate support 250 includes one or more actuators 260, such as a drive motor or pneumatic motor, for moving the one or more substrate supports 250 (e.g., support rollers 251) into or out of engagement with the substrate 201. For example, the actuator 260 can raise the substrate supports 250 to an extended position where they can receive and support the substrate 201. The actuator 260 can also lower the substrate supports 250 to a retracted position where they are moved away from the substrate 201. When the substrate supports 250 are in the extended position, the substrate 201 is in position for engagement with and retained by the substrate holder 210. After the substrate 201 is retained by the substrate holder 210 (such as via the vacuum chuck 215), the substrate supports 250 are lowered to the retracted position, where they are no longer in contact with the substrate 201. The position of the substrate supports 250 can be controlled by the controller 160.

[0041] In some embodiments, the brush cleaner 200 includes a notch detector 290. The notch detector 290 is configured to detect a notch 216 in the substrate 201. In this respect, the notch detector 290 can be used to determine the number of rotations, the rotational speed and / or the orientation of the substrate 201. In some example, the detected orientation of the substrate 201 is used to control the orientation of the substrate 201. In the example of Figure 2, the notch 216 is located in the outer ring portion 237 of the substrate 201. In some examples, the notch detector 290 is a contactless notch detector. For example, notch detector 290 is an optical sensor configured to direct a light toward the substrate 201 and detect the notch 216 based44025320W001 on whether the light is blocked by the substrate 201 or passes through substrate 201. Rotation and rotational speed data from the notch detector 290 may be sent to the controller 160.

[0042] In some embodiments, the brush cleaner 200 may include one or more sprayers 271 coupled to a source 273 of cleaning fluid 274 via a supply pipe 276. The sprayers 271 are configured to dispense a high-pressure liquid spray onto the substrate surfaces, aiding in the removal of particles, such as contaminants and residues. The sprayers 271 can incorporate various configurations, such as a fluid jet, spray bar with nozzles, shower-style spray manifold, or cryogenic aerosol jet.

[0043] In various embodiments, the cleaning fluid 274 utilized in the brush cleaner 200 may include, but is not limited to deionized (DI) water, diluted citric acid, diluted Quaternary ammonium compound (a mixture of organic solvents, such as glycol ether, tetramethyl ammonium hydroxide, and other additives), diluted ammonium hydroxide (NH4OH), diluted hydrogen peroxide (H2O2), NH4OH and H2O2 mixture (SC1), diluted hydrofluoric acid, sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) mixture, Electra clean, or any other liquid solution used for substrate cleaning.

[0044] In one or more embodiments, the sprayers 271 may be positioned to spray a cleaning fluid 274 at the surfaces of the substrate 201 , at the cylindrical roller 228, or both during a scrubbing process. In one or more embodiments, substrate cleaning fluid 274 may be supplied from an internal region of the cylindrical roller 228. Fluids provided to the interior of the cylindrical roller 228 may clean the surface of the substrate 201 or remove debris found on the surface of the roller 228.

[0045] Figure 5 illustrates an exemplary sprayer 271 for spraying the substrate 201 , according to some embodiments. The substrate 201 is disposed in the tank 205 of the brush cleaner 200 and supported on two support rollers 251. The brush cleaner 200 also includes a notch detector 290. In this example, the sprayer 271 includes a spray bar 277 and a plurality of nozzles 278, according to some embodiments. As shown, the spray bar 277 includes three nozzles 278a-c that are spaced apart on the spray bar 277. While only three nozzles 278 are shown, the spray bar 277 may include one, two, four, five or more nozzles 278. In this example, one or more of the nozzles 278a-c are configured to provide a different fluid spray coverage of the substrate 201.44025320W001 For example, the nozzles 278a-c may have different spray width based on the area of the substrate 201 covered by the nozzles 278a-c. As shown, the first nozzle 278a has the largest spray width 279a because it covers the outer portion of the substrate 201 , which outer portion has the fastest rotational speed. The second nozzle 278b has an intermediate spray width 279b because it covers the intermediate portion of the substrate 201. The third nozzle 278c has the narrowest spray width 279c because it covers the central portion of the substrate 201. In some embodiments, two or more of the nozzles 278a-c may have the same spray coverage. For example, the second and third nozzles 278b, 278c may have the same spray width. In some embodiments, the nozzles 278a-c may be also spray fluid onto the cylindrical roller 228.

[0046] In some embodiments, the brush cleaner 200 may include a substrate edge cleaner 280. The edge cleaner 280 may contact and clean the bevel of the substrate 201. In one example, the edge cleaner 280 is a brush. In another example, the edge cleaner 280 includes one or more nozzles arranged to spray the edge or the outer ring portion 237 on the backside of the substrate 201.

[0047] Figures 4a-4J illustrate a process flow diagram for cleaning a substrate, e.g. , substrate 201, which may be performed by a controller of a CMP system, e.g., controller 160 of CMP system 100.

[0048] As shown in Figure 4A, a substrate 201 is placed in a brush cleaner 200. The brush cleaner 200 may be used as a brush or buffing pad module 131 , 132 of the CMP system 100. In some embodiments, the substrate 201 is transferred to the brush cleaner 200 after being polished in a polishing station of the polishing stations 118. The substrate 201 may be transferred using the conveyor 130 and may be inserted into the brush cleaner 200 through the door (not shown) at the top of the brush cleaner 200. As shown, the cylindrical roller 228 and the substrate holder 210 are in the retracted position to allow insertion of the substrate 201. In this example, the substrate support 250 are support rollers 251, and the support rollers 251 are in the extended position, ready to receive the substrate 201.

[0049] Figure 4B shows the substrate 201 disposed in a vertical orientation on the support rollers 251. In this embodiment, the substrate 201 is disposed in the groove 253 of the support rollers 251.44025320W001

[0050] The substrate holder 210 is moved toward the substrate 201 and retains the substrate 201, as shown in Figure 4C. In this embodiment, the substrate holder 210 includes a vacuum chuck 215, and the vacuum pump 214 is activated to cause the vacuum chuck 215 to retain the substrate 201. In some embodiments, a retaining film 222 is disposed between the vacuum chuck 215 and the substrate 201 and used to facilitate the vacuum chuck 215 retaining the substrate 201. After the substrate 201 is retained by the vacuum chuck 215, the support rollers 251 are retracted away from the substrate 201 , as shown in Figure 4D. The substrate 201 is retained in the vertical orientation by the vacuum chuck 215.

[0051] In Figure 4E, the vacuum chuck 215 is rotated by using the motor 203 to rotate the drive shaft 218. In turn, the substrate 201 is rotated by the vacuum chuck 215. Figure 4E also shows the cylindrical roller 228 has started rotating.

[0052] In Figure 4F, the cylindrical roller 228 is extended into contact with the substrate 201 to clean the substrate 201. The cylindrical roller 228 is pressed against the front side of the substrate 201. In this example, the longitudinal axis of the cylindrical roller 228 is in longitudinal alignment (e.g., substantially parallel) with the front side of the substrate 201. In this respect, the cylindrical roller 228 can advantageously clean the substrate 201 without being placed in a toe-in configuration with respect to the substrate 201. To clean the substrate 201 , the cylindrical roller 228 is rotated in the clockwise direction 192 in the x-y plane, and the substrate 201 is rotated in clockwise direction 196 in the y-z plane. During cleaning, the sprayers 271 may apply cleaning fluid 274 to the surfaces of the substrate 201 as the roller 228 and the substrate 201 are rotated. In some examples, the sprayers 271 may also apply cleaning fluid to the roller 228.

[0053] After cleaning, the cylindrical roller 228 is retracted away from the substrate 201, as shown in Figure 4G. In Figure 4H, rotation of the roller 228 and the vacuum chuck 215 is stopped.

[0054] In Figure 4I, the substrate support 250 is raised to the extended position to support the substrate 201. Thereafter, the substrate 201 is released from the vacuum chuck 215. For example, fluid can be supplied via the conduit 223 to the top surface of vacuum chuck 215 to release the substrate 201. The supplied fluid may beneficially44025320W001 clean the backside of the substrate 201 as the substrate 201 is being released. After releasing the substrate 201, the vacuum chuck 215 is retracted away from the substrate 201.

[0055] In Figure 4 J , the substrate 201 is removed from the brush cleaner 200. For example, the substrate 201 may be removed from the tank 205 using the conveyor 130. In this manner, the substrate 201 may be efficiently cleaned using a single cylindrical roller 228.

[0056] In some embodiments, after cleaning, the substrate 201 is transferred to a non-contact cleaning unit, such as a megasonic cleaner 133 and / or a drying module 134. The non-contact cleaning unit then cleans the substrate 201 using a non-contact cleaning method, such as megasonic cleaning or spray cleaning. For example, the substrate 201 may undergo spray cleaning where high-pressure jets of cleaning solution are directed toward the substrate 201 to dislodge particles and contaminants. It is contemplated that the substrate 201 may be transferred to a second brush or buffing pad module 131, 132 instead of or in addition to the non-contact cleaning unit. In some embodiments, after cleaning, the substrate 201 is transferred to the factory interface module 102 and cassettes 110.

[0057] In some embodiments, after cleaning, the substrate 201 is transferred to a polishing station of the polishing stations 118 for polishing or additional polishing if the substrate 201 was previously polished. After polishing, the substrate 201 is transferred to a non-contact cleaning unit, such as a megasonic cleaner 133 and / or a drying module 134.

[0058] Figure 6 illustrates another exemplary vacuum chuck 415 suitable for use with the substrate holder 210, according to some embodiments. In this example, the upper surface 417 of the vacuum chuck 415 has a concave shape. The vacuum chuck 415 includes a suction channel 418 in fluid communication with a vacuum pump (e.g., vacuum pump 214) within the drive shaft 218. For example, pneumatic gas (such as air or nitrogen) and / or liquid is pumped away from the concave, upper surface 417 to create a negative pressure behind the substrate 201. The atmospheric pressure on the other (“front”) side of the substrate 201 retains the substrate 201 against the chuck 215. Although a concave shape is shown, the vacuum chuck 415 may have other44025320W001 suitable shapes such as a convex shape or have other suitable features that enable the substrate 201 to take a concave or convex shape. An optional retainer film 222 can be disposed on the upper surface 417 of the vacuum chuck 415. In some examples, the outer diameter of the upper surface 417 of the vacuum chuck 415 is smaller than the outer diameter of the substrate 201.

[0059] In operation, the vacuum pump 214 is activated to cause the vacuum chuck 415 to retain the substrate 201. In some embodiments, the negative pressure applied is sufficient to cause the substrate 201 to deflect and conform to the concave shape of the upper surface 417 of the vacuum chuck 415, as shown in Figure 7. In this respect, the profile of the substrate 201 can be selectively controlled to optimize cleaning. For example, the concave profile of the substrate 201 may be implemented near the end of the cleaning process to drive dirty cleaning fluid off of the substrate 201. In another example, the concave profile of the substrate 201 is implemented to compensate for uneven wear on the cylindrical roller 228. To release the substrate 201, pneumatic air is pumped through the plurality of holes 212 toward the upper surface of the vacuum chuck 215.

[0060] The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0061] The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, the objects A and C may still be considered coupled to one another — even if objects A and C do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly in physical contact with the second object.

[0062] 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

44025320W001 What is claimed is:

1. A brush cleaning system for cleaning a substrate, comprising:a tank;a cylindrical roller disposed in the tank for cleaning the substrate;a substrate holder for retaining the substrate in a vertical orientation and rotating the substrate; anda movable substrate support for supporting the substrate in the tank.

2. The brush cleaning system of claim 1 , wherein the cylindrical roller is configured to clean a front side of the substrate, and the substrate holder is configured to retain a back side of the substrate.

3. The brush cleaning system of claim 1 , wherein the substrate support is movable between an extended position for engaging the substrate and a retracted position for disengaging the substrate.

4. The brush cleaning system of claim 3, wherein when the substrate support is in the extended position, the substrate is in position to be retained by the substrate holder.

5. The brush cleaning system of claim 1 , wherein the substrate support comprises one or more support rollers.

6. The brush cleaning system of claim 1 , wherein the substrate holder comprises a vacuum chuck.

7. The brush cleaning system of claim 6, wherein the vacuum chuck comprises a concave, upper surface for engaging the substrate.

8. The brush cleaning system of claim 6, wherein the substrate holder is configured to release the substrate from the vacuum chuck or the electrostatic chuck using a liquid.44025320W0019. The brush cleaning system of claim 1 , wherein the substrate holder is movable between an extended position for engaging the substrate and a retracted position for disengaging the substrate.

10. The brush cleaning system of claim 1 , further comprising one or more sprayers for spraying a fluid at the substrate, the cylindrical roller, or both.

11. The brush cleaning system of claim 10, wherein the one or more sprayers comprise a plurality of nozzles, and the plurality of nozzles are configured to have at least two different spray coverage of the substrate.

12. The brush cleaning system of claim 1, further comprising a notch detector for detecting a notch in the substrate.

13. A method of cleaning a substrate, comprising:supporting a substrate in a vertical orientation on a substrate support; retaining the substrate using a substrate holder;rotating the substrate holder to rotate the substrate; andcleaning the substrate using a cylindrical roller.

14. The method of claim 13, further comprising moving the substrate holder to an extended position to retain the substrate.

15. The method of claim 13, further comprising retracting the substrate support away from the substrate after the substrate holder retains the substrate.

16. The method of claim 15, further comprising extending the substrate support to support the substrate after cleaning.

17. The method of claim 13, wherein retaining the substrate comprises creating a negative pressure in the substrate holder to retain the substrate.44025320W001 18. The method of claim 13, further comprising supplying a liquid to release the substrate from the substrate holder and to clean the substrate.

19. The method of claim 13, wherein the substrate includes a notch, and the method further comprises at least one of:measuring at least one of a number of rotations or a rotational speed of the substrate using a notch detector, ordetecting or controlling the orientation of the substrate via the notch.

20. The method of claim 13, further comprising spraying a fluid toward the substrate while cleaning the substrate.

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