Improvement of circuit board cleaning

Abstract

A substrate cleaning device is provided, comprising a shaft having an outer body and an internal space, having a length in a first direction; a pad carrier assembly comprising a housing having an internal space, which is connected to the outer body of the shaft at a fixed position with respect to the outer body; a piston disposed within the internal space of the housing, which is movable in the first direction based on pressure changes in the internal space of the shaft; a pad carrier; and a flexible member connected between the housing and the pad carrier, which is configured to extend or retract together with the pad carrier in the first direction based on pressure changes in the internal space of the shaft.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to an apparatus and method for improving the cleaning of a substrate (e.g., a semiconductor substrate) by improving the control of the pressure applied from a cleaning pad onto the substrate during cleaning.

Background Art

[0002] Description of Related Art

[0002] Chemical mechanical polishing (CMP) is commonly used in the manufacture of high density integrated circuits to planarize or polish a layer of material deposited on a substrate. In a horizontal pre-clean (HPC) module used in a CMP process, a rotating pad is pressed against a material layer on the surface of the substrate, and the material is removed across the material layer by a combination of the chemical and mechanical activity provided by a cleaning fluid, and the relative movement between the pad and the substrate. A motor positioned on the pad is used to rotate the pad. The pressure applied to the substrate by the pad can be adjusted, for example, by using a sliding mechanism to move the position (e.g., vertical position) of the motor. Due to the change in frictional force over the service life of the equipment, it can be difficult to achieve accurate and consistent cleaning results when adjusting the pressure applied by the pad (i.e., adjusting the position of the motor using a sliding mechanism).

[0003]

[0003] Therefore, there is a need for improved apparatuses and related methods that can achieve more accurate and consistent application of pressure by a pad for cleaning a substrate during an HPC process and other similar processes.

Summary of the Invention

[0004]

[0004] In one embodiment, a substrate cleaning device is provided, comprising a shaft having an outer body and an internal space having a length in a first direction, and a pad carrier assembly comprising a housing having an internal space, which is connected to the outer body of the shaft at a fixed position with respect to the outer body, a piston disposed in the internal space of the housing and which is movable in the first direction based on pressure changes in the internal space of the shaft, a pad carrier, and a flexible member connected between the housing and the pad carrier, which is configured to extend or retract together with the pad carrier in the first direction based on pressure changes in the internal space of the shaft.

[0005]

[0005] In another embodiment, a substrate cleaning device is provided, comprising a shaft having an outer body and an internal space, having a length in a first direction, and a pad carrier assembly comprising a housing having an internal space, a piston disposed within the internal space of the housing and movable in the first direction, a pad carrier, and a diaphragm positioned between the piston and the upper part of the housing, configured to form a seal between the internal space of the shaft and one or more portions of the internal space of the housing located below the diaphragm.

[0006]

[0006] In another embodiment, a substrate cleaning apparatus comprising a substrate support, a shaft having an outer body and an internal space having a length in a first direction, a pad carrier assembly comprising a housing having an internal space, a piston disposed in the internal space of the housing and movable in a first direction, a pad carrier, and a flexible member having an upper and lower part, the upper part of which is connected to the housing and the lower part of which is connected to the pad carrier, and a controller configured to adjust the pressure in the internal space of the shaft to extend the flexible member in the first direction and bring the pad carrier closer to the substrate support.

[0007]

[0007] To enable a detailed understanding of the features of the Disclosure listed above, a more detailed description of the Disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only exemplary embodiments and should not be considered to limit the scope of the Disclosure, as other equally valid embodiments are also permissible. [Brief explanation of the drawing]

[0008] [Figure 1] A side cross-sectional view of a cleaning system according to one embodiment is shown. [Figure 2] This is a side cross-sectional view of the pad carrier positioning system and several other components of the cleaning system shown in Figure 1, according to one embodiment. [Figure 3A] Figures 1 and 2 are side cross-sectional views of the pad carrier positioning system according to one embodiment, and show some additional details relating to the pad carrier positioning system. [Figure 3B] Figures 1 and 2 are side cross-sectional views of the pad carrier positioning system according to one embodiment, and show some additional details relating to the pad carrier positioning system. [Modes for carrying out the invention]

[0009]

[0012] To facilitate understanding, the same reference numerals were used where possible to indicate identical elements common to multiple figures. It is assumed that elements and features of one embodiment may be usefully incorporated into other embodiments without further description.

[0010]

[0013] Embodiments of this disclosure generally relate to apparatus and methods for improving the application of pressure to a substrate (e.g., a semiconductor substrate) during a cleaning process. The improvement is achieved by applying pressure to the internal space of a shaft that rotates a cleaning pad during cleaning of the substrate. The pressure applied to the internal space of the shaft causes a flexible member attached to a pad carrier to spring downward, causing the cleaning pad, held by the pad carrier, to contact the substrate during cleaning. The pressure in the internal space of the shaft can be precisely adjusted to precisely control the pressure applied to the substrate by the cleaning pad during cleaning. The flexible member configured to stretch like a spring may also have torsional rigidity, so that adjustment of the torque applied to the shaft is independent of the downward pressure applied by the flexible member and is parallel to the pressure applied by the cleaning pad.

[0011]

[0014] Adjusting the pressure applied to the substrate by the cleaning pad by adjusting the pressure applied to the internal space of the shaft that rotates the cleaning pad is an improvement over conventional cleaning systems that move a motor that rotates the shaft. Adjusting the pressure applied to the substrate during cleaning using the vertical motion of the shaft and motor can result in an inconsistent cleaning method because factors (e.g., friction) fluctuate over the lifespan of conventional cleaning systems. The cleaning system disclosed herein solves this problem by allowing the vertical position of the shaft and motor to remain stationary while varying the pressure applied to the substrate. Using the cleaning system disclosed herein, the pressure applied to the substrate during cleaning is adjusted by adjusting the pressure in the internal space of the shaft that rotates the cleaning pad. The pressure in the internal space of the shaft can then be used to adjust the pressure applied to the cleaning pad using a diaphragm and a flexible member (e.g., a spring). Using the cleaning system disclosed herein, the pressure applied to the substrate can be adjusted with high precision using a frictionless design, resulting in more consistent and higher-quality cleaning results than conventional cleaning systems. The following primarily describes an improved system for cleaning substrates (e.g., removing foreign matter from the substrate surface without scratching the substrate), but the advantages of this disclosure can also be applied to buffing (e.g., removing 10-100 angstroms of the buffing layer) and polishing processes (e.g., CMP processes), improving the consistency and precision of the pressure applied to the substrate during these processes.

[0012]

[0015] Figure 1 shows a side cross-sectional view of a cleaning system 100 according to one embodiment. In one embodiment, the cleaning system 100 (also called a substrate cleaning system) is a high-pressure horizontal (HPC) system used in a chemical mechanical polishing (CMP) process.

[0013]

[0016] The cleaning system 100 includes a cleaning device 101 (also called a substrate cleaning device), a gas source 190, and a controller 175. The cleaning device 101 includes a housing 102. The housing 102 includes a basin 105 and a lid 106 positioned above the basin 105. The housing 102 may include a floor 109 between the lid 106 and the basin 105. Some components within the cleaning device 101 may be mounted on the floor 109 or positioned to extend through the floor 109. The housing 102 encloses an internal space 110 for cleaning substrates 50. The side walls of the lid 106 have been removed for illustrative purposes to show the components within the internal space 110. The lid 106 may include a door 107 for transporting substrates 50 to and from the internal space 110 of the housing 102.

[0014]

[0017] The cleaning apparatus 101 further includes a vacuum table 140 (substrate support) for supporting the substrate 50 during cleaning. The vacuum table 140 may be connected to a vacuum pump 119 (see Figure 2). The vacuum pressure applied to the vacuum table 140 is sufficient to hold the substrate 50 during cleaning. While the substrate support in this disclosure is generally described as a vacuum table, other substrate supports may be used in which other methods of holding the substrate on the substrate support, such as mechanical methods or electrostatic chucking, are employed.

[0015]

[0018] The cleaning apparatus 101 further includes a pad carrier positioning system 200. The pad carrier positioning system 200 includes a shaft 201 and a pad carrier positioning arm 210. The shaft 201 may be connected to an actuator 208 (see Figure 2) to rotate the pad carrier positioning arm 210 over various parts of the substrate 50 (e.g., various radial positions). The pad carrier positioning arm 210 may include a housing 202. The pad carrier positioning arm 210 may include a pad carrier assembly 230 (see Figure 2) at least partially located within the housing 202 and configured to hold and rotate the cleaning pad 60 over various parts of the substrate 50. As will be described in more detail below, the pad carrier positioning arm 210 may further include a motor and shaft at least partially located within the housing 202 to rotate the cleaning pad 60 on the substrate 50 to perform cleaning of the substrate 50. The cleaning apparatus 101 further includes a pad conditioning station 180. The pad carrier positioning arm 210 is configured to move the pad carrier and the cleaning pad 60 from a position above the pad conditioning station 180 to a position above the vacuum table 140.

[0016]

[0019] The gas source 190 may be configured to supply pressurized gas to the pad carrier assembly to move the cleaning pad 60 from a position away from the substrate 50 (e.g., see Figure 3A) to a position where the cleaning pad 60 is pressed against the upper surface of the substrate 50 (e.g., see Figure 3B). The controller 175 can use measurements from one or more pressure sensors (e.g., see sensor 222P in Figure 3A) to adjust the position of one or more valves (not shown) to control the pressure in the internal space of the motor shaft that controls the pressure applied to the cleaning pad 60 and the substrate 50 during cleaning. In some embodiments, a medium other than gas (e.g., a liquid) can be used to adjust the pressure inside the shaft that controls the pressure applied to the cleaning pad 60 and the substrate 50 during cleaning.

[0017]

[0020] The cleaning system 100 also includes a controller 175 for controlling the processes performed by the cleaning system 100. The controller 175 can be any type of controller used in industrial settings (such as a programmable logic controller (PLC)). The controller 175 includes a processor 177, memory 176, and input / output (I / O) circuits 178. The controller 175 may further include one or more of the following components (not shown), such as one or more power supplies, clocks, communication components (e.g., a network interface card), and user interfaces, which are typically found in controllers for semiconductor devices.

[0018]

[0021] Memory 176 may include non-transient memory. Non-transient memory may be used to store the programs and settings described below. Memory 176 may include one or more readily available types of memory, such as read-only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM)).

[0019]

[0022] The processor 177 is configured to execute various programs stored in memory 176, such as different cleaning processes to be performed on different substrates 50. While these programs are being executed, the controller 175 can communicate with I / O devices via I / O circuitry 178. For example, during the execution of these programs and communication via I / O circuitry 178, the controller 175 can control parts of the cleaning process, such as the pressure the cleaning pads 60 exert on the substrates 50 during cleaning, as will be described in more detail below. Memory 176 may further include various operating settings used to control the cleaning system 100.

[0020]

[0023] FIG. 2 is a cross-sectional view of some other components of the pad carrier positioning system 200 and the cleaning system 100 according to an embodiment, shown in FIG. 1. In FIG. 2, a part of the housing 202 of the pad carrier positioning arm 210 is removed for illustrative purposes to show the components located inside the housing 202.

[0021]

[0024] The pad carrier positioning system 200 includes an actuator 208, a shaft 201, and a pad carrier positioning arm 210. In one embodiment, the actuator 208 can be attached to the underside of the floor 109 of the housing 102, and the shaft 201 can extend through the floor 109 to the pad carrier positioning arm 210. The pad carrier positioning arm 210 includes a pad carrier assembly 230 configured to hold the cleaning pad 60 during cleaning. The actuator 208 is configured to rotate the shaft 201 and the pad carrier positioning arm 210 about an axis C1 to move the pad carrier assembly 230 to various positions over various portions of the substrate 50 (e.g., various radial positions of the substrate 50), or to other positions such as over the pad conditioning station 180 (see FIG. 1).

[0022]

[0025] The cleaning device 101 includes a vacuum table 140 and a vacuum pump 119 fluidly connected to the vacuum table 140. The vacuum pump 119 can apply a vacuum pressure to the vacuum table 140 to fix the substrate 50 to the vacuum table 140 during cleaning. The cleaning device 101 may further include an actuator 145 and a shaft 146. In one embodiment, the actuator 145 can be attached to the underside of the floor 109 of the housing 102, and the shaft 146 can extend through the floor 109. The shaft 146 connects the actuator 145 to the vacuum table 140. The actuator is configured to rotate the shaft 146 and the vacuum table 140 about an axis C2 to rotate the substrate 50 on the vacuum table 140 during cleaning.

[0023]

[0026] The pad carrier positioning arm 210 includes a motor 215, a shaft 220, and a pad carrier assembly 230. A cleaning pad 60 can be fixed to the pad carrier assembly 230 during cleaning. The motor 215 may be configured to rotate the shaft 220 and the pad carrier assembly 230 in the Z direction (first direction) around a vertical axis. The pad carrier assembly 230 is connected to the shaft 220. Thus, the rotation of the shaft 220 causes the pad carrier assembly 230 and the cleaning pad 60 fixed to the pad carrier assembly 230 to rotate, thereby allowing the substrate 50 to be cleaned by the rotating pad 60.

[0024]

[0027] The shaft 220 includes an outer body 221 positioned around an internal space 222. A motor 215 is configured to rotate the outer body 221 of the shaft 220. The internal space 222 may be connected to a gas source 190 by one or more gas lines 290. The pad carrier positioning arm 210 may further include a rotary union 291 that connects one or more gas lines 290 to the internal space 222 in order to maintain the gas connection as the shaft 220 rotates. The internal space 222 is connected to the rotary union 291 at a first end 223 of the internal space 222 and to the pad carrier assembly 230 at a second end 224 of the internal space 222. The first end 223 is spaced away from the second end 224 along the length of the shaft 220 in the Z direction (first direction). In one embodiment, one or more gas lines 290 extend from the rotary union 291 through the pad carrier positioning arm 210 and through the shaft 201 to the gas source 190.

[0025]

[0028] The pad carrier assembly 230 includes an upper housing 231 and a lower housing 232. The upper housing 231 can be connected to the outer body 221 of the shaft 220 at a position fixed relative to the outer body 221 of the shaft 220. Thus, the rotation of the shaft 220 rotates the upper housing 231. The lower housing 232 can be coupled to the upper housing 231. In some embodiments, the upper housing 231 and the lower housing 232 can be formed in one integral structure. The upper housing 231 and the lower housing 232 can be disposed around an internal space 235.

[0026]

[0029] The pad carrier assembly 230 may further include a diaphragm 240, a clamp plate 245, and a piston 255. The piston 255 and the clamp plate 245 can be positioned within the internal space 235 of the upper housing 231 and the lower housing 232. The diaphragm 240 includes an outer portion fixed to one or more of the upper housing 231 and the lower housing 232. In one embodiment, the outer portion of the housing is held (e.g., fixed) between the upper housing 231 and the lower housing 232.

[0027]

[0030] The diaphragm 240 further includes an inner portion 241 (see FIG. 3A) attached to the piston 255. A portion of the inner portion 241 of the diaphragm 240 can be attached to the piston 255 by the clamp plate 245. The inner portion 241 of the diaphragm 240 is partially positioned between the clamp plate 245 and the piston 255. In some embodiments, a fastener 246 can extend through the clamp plate 245, through the inner portion of the diaphragm 240, and into the piston 255 to attach the inner portion 241 of the diaphragm 240 to the piston 255.

[0028]

[0031] When pressure is applied from the gas source 190 to the internal space 222 of the shaft 220, the clamp plate 245, a portion of the inner part 241 of the diaphragm 240 (Figure 3A), and the piston 255 move downward in the Z direction (first direction) relative to the upper housing 231 and the lower housing 232, bringing the cleaning pad 60 closer to the substrate 50 (see Figure 3B). The diaphragm 240 can be made of a flexible material such as rubber or synthetic rubber (e.g., ethylene propylene diene monomer rubber). The diaphragm 240 is configured to form a seal between the internal space 222 of the shaft 220 and the portion of the internal space 235 below the diaphragm 240. The inner portion 241 of the diaphragm 240 (see Figure 3A) can deform in response to an increase in pressure within the internal space 222 of the shaft 220, allowing the piston 255 to move downward in the Z direction while maintaining a seal between the internal space 222 of the shaft 220 and the portion of the internal space 235 of the housings 231, 232 below the diaphragm 240. As the piston 255 moves downward, the volume of the pressurized space above the diaphragm 240 increases, and the volume of the space within the internal space 235 below the diaphragm 240 decreases.

[0029]

[0032] The pad carrier assembly 230 may further include a flexible member 250 and a pad carrier 260. The pad carrier 260 is separated from the vacuum table 140 in the Z direction (first direction). The pad carrier 260 can hold the cleaning pad 60 so that the cleaning pad 60 can be rotated and pressed against the substrate 50 during cleaning of the substrate 50. The pad carrier 260 may be connected to the lower part of the flexible member 250. The upper part of the flexible member 250 may be connected to the lower housing 232.

[0030]

[0033] The piston 255 and pad carrier 260 are not firmly connected to other components within the pad carrier assembly 230. When increased pressure is applied from the gas source 190 to the internal space 222 of the shaft 220, the lower part of the piston 255 moves and presses against the upper surface of the pad carrier 260, applying a downward force in the Z direction (first direction), causing the flexible member 250 to stretch in the Z direction. Stretching the flexible member 250 in the Z direction allows the cleaning pad 60 and pad carrier 260 to move closer to the substrate 50 positioned on the vacuum table 140, and to apply pressure to the substrate 50 after contact between the pad 60 and the substrate 50 has occurred. In some embodiments, the flexible member 250 may be configured to stretch from about 2 mm to about 20 mm in the Z direction, for example, from about 6 mm to about 8 mm in the Z direction.

[0031]

[0034] The flexible member 250 (also called a spring) can be formed from an elastic material. In one embodiment, the flexible member 250 may be made of plastic or metal (e.g., steel). The flexible member 250 can generally be designed to be highly resistant to deformation caused by torque forces during rotation of the pad carrier assembly 230 and to have torsional rigidity. Furthermore, the torsional rigidity of the flexible member 250 allows lateral forces in the XY plane to be transmitted from the rotating shaft 220 and through the similarly torsionally rigid flexible member 250 and pad carrier 260.

[0032]

[0035] On the other hand, the flexible member 250 may be axially flexible in the Z direction. In some embodiments, the flexible member 250 may function as an extension spring. By increasing the pressure in the internal space 222, repeatable and precise extension of the flexible member 250 in the Z direction and the pressure applied to the substrate 50 when the cleaning pad 60 contacts the substrate 50 during cleaning of the substrate 50 can be provided. The flexible member 250 can be described as having greater torsional stiffness than axial stiffness in the Z direction. In some embodiments, the flexible member 250 has substantially greater torsional stiffness in the Z direction compared to its axial stiffness (e.g., at least 10 times or at least 100 times). For example, a flexible member having torsional rigidity 100 times greater than its axial rigidity can be described as a flexible member in which an axial force and a torsional force 100 times greater than the axial force can each displace a portion of the flexible member 250 by the same distance.

[0033]

[0036] The extension of the flexible member 250 is also a frictionless or near-frictionless design that can produce more consistent results for applying pressure to the substrate 50 via the cleaning pad 60 than conventional cleaning systems that move a shaft and / or motor vertically to adjust the pressure applied to the substrate by the cleaning pad. This vertical movement of the shaft and / or motor in conventional cleaning systems generally makes it difficult to obtain consistent results for applying a precise amount of pressure to the cleaning pad during substrate cleaning by using components that slide against each other and changing the frictional properties of these components over time. These problems in conventional cleaning systems can also be more serious with respect to cleaning processes where the pressure applied to the substrate is relatively low, for example, with respect to substrate cleaning processes, because the frictional force resisting the movement of sliding elements passing through each other is the magnitude of the downward force applied by the cleaning system to achieve a particular pressure for the substrate cleaning process. The cleaning system disclosed herein also enables the cleaning process to be performed at lower pressures than is typically achievable using conventional cleaning systems.

[0034]

[0037] By making the flexible member 250 torsionally rigid but flexible in the Z direction, the axial pressure in the Z direction applied to the substrate 50 by the cleaning pad 60 in response to the pressure in the internal space 222 can be made independent of the torque applied to the cleaning pad 60 by the motor 215. By making the axial force in the Z direction independent of the torque, the cleaning process performed by the cleaning system 100 can be controlled more precisely compared to conventional cleaning systems, resulting in improved product quality and more consistent cleaning results over time. Conventional cleaning systems are generally designed to move the motor that rotates the cleaning pad vertically in order to change the pressure applied to the substrate by the cleaning pad. Moving a heavy motor vertically and due to variations in frictional force over the lifespan of the cleaning equipment makes it difficult to obtain consistent and accurate results for applying pressure to the substrate during cleaning. As described above, this disclosure can solve this problem by adjusting the pressure applied by the cleaning pad to the substrate 50 by changing the pressure applied to the substrate 50 by moving the cleaning pad 60 while keeping the motor 215 stationary, and / or by changing the pressure applied to the internal space 222.

[0035]

[0038] In some embodiments, when the pressure in the internal space 222 of the shaft 220 is relieved (e.g., returned to atmospheric pressure), the spring constant of the flexible member 250 is sufficient to pull back the cleaning pad 60 and pad carrier 260. In some embodiments, the flexible member 250 may be mechanically coupled with another spring (not shown) to assist in the expansion and contraction of the pad carrier 260 and pad 60. In some embodiments, a pressure below atmospheric pressure can be applied to the internal space 222 of the shaft 220 to assist in the retraction of the pad 60 and pad carrier 260. The flexible member 250 may also be configured to have a different design in some embodiments. For example, in one embodiment, a bellows can be used to perform the function of the flexible member 250 described herein.

[0036]

[0039] Figure 3A is a side cross-sectional view of the pad carrier positioning system 200 of Figures 1 and 2 according to one embodiment, and shows some additional details relating to the pad carrier positioning system 200. In Figure 3A, the cleaning pad 60 is positioned away from the substrate 50.

[0037]

[0040] In some embodiments, the pad carrier positioning system 200 may include a pressure sensor 222P positioned to measure the pressure in the internal space 222 of the shaft 220. In other embodiments, the pressure sensor may be positioned at a different location along one of the gas lines 290. In Figure 3A, the pressure P1 in the internal space 222 measured by the pressure sensor 222P is a low pressure, such as atmospheric pressure. The controller 175 may adjust the position of one or more valves (not shown) to achieve the low pressure P1 by, for example, closing one or more valves connected to the supply of the gas source 190 (see Figure 1) and venting the gas line 290 and the internal space 222 to the atmosphere. At low pressure, the flexible member 250 relaxes, the piston 255 rises to the position shown in Figure 3A, and the pad carrier 260 and the cleaning pad 60 are separated from the substrate 50. As shown in Figure 3A, the lower part 252 of the flexible member 250 approaches the upper part 251 of the flexible member 250. The upper part 251 of the flexible member 250 is attached to the lower housing 232. The lower part 252 of the flexible member 250 is connected to the pad carrier 260.

[0038]

[0041] Furthermore, at low pressure (e.g., P1), the piston 255 is in an elevated position within the internal space 235 of the housings 231, 232. The inner portion 241 of the diaphragm 240 is located between the clamp plate 245 and the piston 255. The outer portion 242 of the diaphragm 240 is held in a stationary position (e.g., clamped) between the upper housing 231 and the lower housing 232. The lower housing 232 may include a hard stop 238 to prevent the diaphragm 241 and the flexible member 250 from accidentally being excessively displaced under pressure when the pad carrier positioning arm 210 is not on the substrate 50 or the pad conditioning station 180. Thus, the hard stop 238 is configured to prevent damage to the diaphragm 241 and / or the flexible member 250. The pad carrier assembly 230 may also include a number of fasteners 239 that connect some of the various components within the pad carrier assembly 230 to each other. For example, in one embodiment, the fastener 239 can connect the upper part 251 of the flexible member 250 to the lower housing 232. The connection of the upper part 251 of the flexible member 250 to the lower housing 232, and the connection of the lower part 252 of the flexible member 250 to the pad carrier 260 is one example of how the flexible member can be configured to assist the expansion and contraction of the pad carrier 260 and the pad 60 when the pressure changes within the internal space 222 of the shaft 220. More generally, the flexible member 250 is configured to shift the pressure within the internal space 222 of the shaft 220 so that the pad carrier 260 and the pad 60 can be pressed against the substrate 50, pressure can be applied to the substrate 50 during cleaning (see Figure 3B), and the pad carrier 260 and the pad 60 can be pulled away from the substrate 50 (see Figure 3A).

[0039]

[0042] Figure 3B is a side cross-sectional view of the pad carrier positioning system 200 of Figures 1 and 2 according to one embodiment, and shows some additional details relating to the pad carrier positioning system 200. In Figure 3B, the cleaning pad 60 is positioned relative to the substrate 50.

[0040]

[0043] In Figure 3B, the pressure P2 in the internal space 222, measured by the pressure sensor 222P, is a high pressure, such as a pressure higher than atmospheric pressure. The controller 175 can adjust the position of one or more valves (not shown) connected to the gas source 190 (see Figure 1) to achieve a higher pressure P2. At higher pressures, the flexible member 250 stretches, and the pad carrier 260 and cleaning pad 60 are positioned closer to or relative to the substrate 50. The pressure in the internal space 222 can be increased from the pressure P1 shown in Figure 3A (e.g., atmospheric pressure) to a higher pressure at which the cleaning pad 60 contacts the substrate 50 at light pressure, and then the pressure in the internal space 222 can be further increased to apply a specific amount of pressure to the cleaning pad 60 on the substrate 50 during cleaning.

[0041]

[0044] As shown in Figure 3B, the lower part 252 of the flexible member 250 is separated from the upper part 251 of the flexible member 250 by a greater distance in the Z direction than in Figure 3A because the pressure P1 in the internal space 222 is higher than the pressure P1 in the internal space 222 in Figure 3A. In Figure 3B, the piston 255 is in a lowered position within the internal space 235 of the housings 231, 232. As the piston 255 descends within the internal space 235, a portion of the inner part 241 of the diaphragm 240 rotates on the inner wall of the lower housing 232, maintaining a seal between the internal space 222 and the portion of the internal space 235 below the diaphragm 240.

[0042]

[0045] The piston 255 may include an outer rim 256 configured to contact the hard stop 238 when the pressure in the internal space 235 rises to a level that sufficiently stretches the flexible member 250 in the Z direction, causing the outer rim 256 to contact the hard stop 238. The hard stop 238 is configured to prevent further movement of the pad carrier 260 and the cleaning pad 60 in the Z direction (first direction), thereby preventing damage to the substrate 50 and the vacuum table 140.

[0043]

[0046] The above applies to embodiments of the present disclosure, but other embodiments and further embodiments of the present disclosure can be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

Claims

1. A substrate cleaning apparatus, A shaft having an outer body and an internal space, having a length in a first direction, A pad carrier assembly, A housing connected to the outer body of the shaft at a fixed position, the housing having an internal space, A piston disposed within the internal space of the housing, the piston being movable in the first direction based on a pressure change in the internal space of the shaft, Pad carrier, and A flexible member connected between the housing and the pad carrier, configured to extend or retract in the first direction together with the pad carrier based on the pressure change in the internal space of the shaft. Pad carrier assembly including A substrate cleaning device equipped with the following features.

2. The substrate cleaning apparatus according to claim 1, wherein the piston is configured to apply force to the pad carrier in the first direction, thereby extending the flexible member in the first direction.

3. The substrate cleaning apparatus according to claim 1, further comprising a motor configured to rotate the shaft and the pad carrier assembly.

4. The substrate cleaning apparatus according to claim 1, further comprising a diaphragm positioned between the piston and the upper part of the housing, wherein the diaphragm is configured to form a seal between the internal space of the shaft and one or more portions of the internal space of the housing located below the diaphragm.

5. The substrate cleaning apparatus according to claim 4, wherein the outer portion of the diaphragm is connected to the housing, and the inner portion of the diaphragm is configured to deform the piston in response to an increase in pressure in the internal space of the shaft, thereby moving the piston in the first direction.

6. The substrate cleaning apparatus according to claim 5, wherein the inner portion of the diaphragm is attached to the piston.

7. The substrate cleaning apparatus according to claim 1, further comprising a rotary union connected to the first end of the internal space of the shaft.

8. A substrate cleaning apparatus according to claim 1, further comprising a vacuum table configured to support a substrate, the vacuum table being separated from the pad carrier in the first direction.

9. The substrate cleaning apparatus according to claim 1, wherein the pad carrier assembly includes a hard stop configured to prevent further movement of the pad carrier in the first direction.

10. The substrate cleaning apparatus according to claim 1, wherein the flexible member includes an upper part and a lower part, the upper part being connected to the housing and the lower part being connected to the pad carrier.

11. The substrate cleaning apparatus according to claim 1, wherein the flexible member has greater torsional rigidity than axial rigidity.

12. The substrate cleaning apparatus according to claim 1, wherein the flexible member has torsional rigidity at least 10 times its axial rigidity.

13. A substrate cleaning apparatus, A shaft having an outer body and an internal space, having a length in a first direction, A pad carrier assembly, A housing connected to the outer body of the shaft at a fixed position, the housing having an internal space, A piston disposed within the internal space of the housing, the piston being movable in the first direction, Pad carrier, and A diaphragm positioned between the piston and the upper part of the housing, wherein the diaphragm is configured to form a seal between the internal space of the shaft and one or more portions of the internal space of the housing located below the diaphragm. Pad carrier assembly including A substrate cleaning device equipped with the following features.

14. The substrate cleaning apparatus according to claim 13, wherein the outer portion of the diaphragm is connected to the housing, and the inner portion of the diaphragm is configured to deform the piston in response to a pressure increase in the internal space of the shaft, thereby moving the piston in the first direction.

15. The substrate cleaning apparatus according to claim 14, wherein the inner portion of the diaphragm is attached to the piston.

16. The substrate cleaning apparatus according to claim 15, further comprising a flexible member having an upper part and a lower part, wherein the upper part is connected to the housing and the lower part is connected to the pad carrier.

17. The substrate cleaning apparatus according to claim 16, wherein the piston is configured to apply force to the pad carrier in the first direction, thereby extending the flexible member in the first direction.

18. The substrate cleaning apparatus according to claim 13, wherein the pad carrier assembly includes a hard stop configured to prevent further movement of the pad carrier in the first direction.

19. A circuit board cleaning system, A substrate cleaning apparatus, Substrate support and A shaft having an outer body and an internal space, having a length in a first direction, A pad carrier assembly, A housing connected to the outer body of the shaft at a fixed position, the housing having an internal space, A piston disposed within the internal space of the housing, the piston being movable in the first direction, Pad carrier, and A flexible member having an upper part and a lower part, wherein the upper part is connected to the housing and the lower part is connected to the pad carrier. Pad carrier assembly including A substrate cleaning apparatus including, A controller configured to adjust the pressure within the internal space of the shaft, thereby extending the flexible member in the first direction and bringing the pad carrier closer to the substrate support. A circuit board cleaning system equipped with the following features.

20. A motor configured to rotate the shaft and the pad carrier assembly, A diaphragm positioned between the piston and the upper part of the housing, configured to form a seal between the internal space of the shaft and one or more portions of the internal space of the housing located below the diaphragm. The substrate cleaning system according to claim 19, further comprising:

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