Silicon wafer polishing pad cleaning device and cleaning method

Abstract

The present invention provides a silicon wafer polishing pad cleaning device, comprising a first water tank and a second water tank for storing cleaning liquid, a brush for cleaning an upper polishing pad and a lower polishing pad, and a mechanical arm for controlling the movement of the brush; the upper end surface of the brush contacts the upper polishing pad, and the lower end surface of the brush contacts the lower polishing pad; the first water tank is connected to the second water tank through a first water pipe, and the second water tank is connected to the brush through the second water pipe; the nozzles arranged at the upper and lower ends of the brush are at a certain angle to the axis of the mechanical arm. The present invention also provides a silicon wafer polishing pad cleaning method. The cleaning device provided by the present invention can completely remove SiO2 colloidal particles, polishing liquid and silicon powder attached to the surface of the polishing pad, has a high degree of automation, good cleaning effect and high efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor silicon wafer polishing, and in particular relates to a silicon wafer polishing pad cleaning device and a cleaning method. Background Art

[0002] Chemical mechanical polishing can obtain a relatively flat surface and a higher polishing rate. The flatness obtained is two orders of magnitude higher than other methods. It is an effective method to achieve global planarization. However, during the chemical mechanical polishing process, some SiO2 colloidal particles in the polishing liquid will agglomerate to form larger particles. Such large particles will adhere to the relatively rough polishing pad during the polishing process. As the number of polishing increases, the number of large SiO2 colloidal particles attached to the polishing pad will increase, causing scratches on the silicon wafer surface during the polishing process. Due to the unreasonable structural design of existing chemical mechanical polishing, it is easy to miss the brush. Many SiO2 colloidal particles are not cleaned up, and polishing liquid and silicon powder are still left on the polishing pad, resulting in poor cleaning effect. Many defective products appear in subsequent polishing, which seriously affects product quality. Summary of the invention

[0003] The problem to be solved by the present invention is to provide a silicon wafer polishing pad cleaning device and a cleaning method, which solves the technical problems of easy brushing leakage and poor cleaning effect during the existing polishing pad cleaning, completely removes SiO2 colloidal particles, polishing solution and silicon powder attached to the surface of the polishing pad, has a high degree of automation, good cleaning effect and high cleaning efficiency.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A silicon wafer polishing pad cleaning device comprises a first water tank and a second water tank for storing cleaning liquid, a brush for cleaning an upper polishing pad and a lower polishing pad, and a mechanical arm for controlling the movement of the brush; the upper end surface of the brush contacts the upper polishing pad, and the lower end surface of the brush contacts the lower polishing pad; the first water tank is connected to the second water tank through a first water pipe, and the second water tank is connected to the brush through the second water pipe; the nozzles arranged at the upper and lower ends of the brush are both at a certain angle to the axis of the mechanical arm.

[0006] Furthermore, the angle is 60°.

[0007] Furthermore, the central axis of the brush is perpendicular to the end surface of the upper polishing pad and the end surface of the lower polishing pad respectively; a T-shaped channel is provided inside the brush, the second water pipe passes through the robotic arm and is connected to one end of the channel, and the nozzle is connected to the other two ends of the channel.

[0008] Furthermore, the upper and lower end surfaces of the brush are both provided with nozzle assemblies, and the nozzle is placed in the middle of the nozzle assembly; the nozzle assembly is suspended at the central axis of the brush end surface and extends outwardly along the length direction of the brush.

[0009] Furthermore, the nozzle assembly further comprises a sleeve clamp for fixing the nozzle and an adjusting member for adjusting the angle of the nozzle, and the nozzle, the sleeve clamp and the adjusting member are arranged in sequence from the inside to the outside.

[0010] Furthermore, the upper and lower end surfaces of the brush are provided with a brush assembly, the brush assembly is arranged in the same direction as the nozzle assembly, the brush assembly is placed outside the nozzle assembly, and there is a gap between the brush assembly and the nozzle assembly.

[0011] Furthermore, a low-pressure water pump is provided in the first water tank; and a high-pressure water pump is provided in the second water tank.

[0012] A method for cleaning a silicon wafer polishing pad, using the cleaning device as described above, comprising the following steps: cleaning liquid sequentially passes through the first water tank and the second water tank through the second water pipe, penetrates the mechanical arm and enters the brush, and then is sprayed onto the upper polishing surface and the lower polishing surface respectively through the nozzle;

[0013] During this process, the upper polishing surface and the lower polishing surface rotate synchronously in opposite directions, and the mechanical arm drives the brush to move horizontally along the radius of the lower polishing surface from outside to inside;

[0014] The water pressure of the first water tank is lower than the water pressure of the second water tank.

[0015] Furthermore, the water pressure of the first water tank is 10-20 bar; the water pressure of the second water tank is 80-120 bar.

[0016] Furthermore, the brush assembly and the nozzle move horizontally and linearly relative to the lower polishing surface.

[0017] The cleaning device designed by the present invention has a simple structure and is easy to control. It solves the technical problem of easy brush leakage during the existing polishing pad cleaning, and completely removes SiO2 colloidal particles, polishing liquid and silicon powder attached to the surface of the polishing pad. It has a high degree of automation, good cleaning effect and high cleaning efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a silicon wafer polishing pad cleaning device according to an embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of the motion trajectory of a cleaning device according to an embodiment of the present invention;

[0020] Figure 3 is a top view of the cooperation between the mechanical arm and the brush according to one embodiment of the present invention;

[0021] Figure 4 is a schematic structural diagram of a brush according to an embodiment of the present invention;

[0022] Figure 5 is a cross-sectional view taken along line AA of an embodiment of the present invention;

[0023] Figure 6 is a schematic structural diagram of a connector according to an embodiment of the present invention;

[0024] Figure 7 The nozzle assembly and the housing of one embodiment of the present invention are matched;

[0025] Figure 8 1 is a top view of an adjusting member according to an embodiment of the present invention.

[0026] In the figure:

[0027] 10. First water tank 11. Low-pressure water pump 12. First water pipe

[0028] 20. Second water tank 21. High-pressure water pump 22. Second water pipe

[0029] 30. Robotic arm 31. First robot arm 32. Second robot arm

[0030] 33. Adapter 34. Engine 40. Brush

[0031] 41. brush body 411. housing 412. connector

[0032] 413, channel 414, gasket 415, retaining ring

[0033] 416, spring thrust piece 42, brush assembly 421, first brush head

[0034] 422, second brush head 423, brush holder 43, nozzle assembly

[0035] 431, nozzle 432, sleeve clamp 433, adjustment piece

[0036] 4331, adjusting cap 4332, adjusting disk 44, connecting assembly

[0037] 441, connecting plate 442, water inlet head 50, upper polishing plate

[0038] 51, upper polishing pad 52, engine 60, lower polishing plate

[0039] 61. Lower polishing pad 62. Engine DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] like Figure 1 A cleaning device for a polishing pad for silicon wafers is shown, which is mainly used to clean SiO2 colloidal particles, polishing liquid and silicon powder adhered to the surface of the polishing pad, and solves the technical problems of easy brush leakage and poor cleaning effect in the prior art. The polishing pad includes an upper polishing pad 51 and a lower polishing pad 61. The upper polishing pad 51 is fixedly mounted on the lower end surface of the upper polishing plate 50, and is driven and controlled to rotate by a motor 52; the lower polishing pad 61 is fixedly mounted on the upper end surface of the lower polishing plate 60, and is driven and controlled to rotate by a motor 62. The upper polishing pad 51 and the lower polishing pad 61 are of the same size and rotate in opposite directions. In this embodiment, the upper polishing pad 51 rotates clockwise, and the lower polishing pad 61 rotates counterclockwise, and the upper polishing pad 51 and the lower polishing pad 61 rotate at the same speed.

[0042] This embodiment provides a silicon wafer polishing pad cleaning device, such as Figure 1-2 As shown, it includes a first water tank 10 and a second water tank 20 for storing cleaning liquid, a brush 40 for cleaning an upper polishing pad 51 and a lower polishing pad 61, and a mechanical arm 30 for controlling the movement of the brush 40. The upper end surface of the brush 40 contacts the upper polishing pad 51, and the lower end surface of the brush 40 contacts the lower polishing pad 61. A low-pressure water pump 11 is provided in the first water tank 10, and a high-pressure water pump 21 is provided in the second water tank 20. The first water tank 10 is connected to the second water tank 20 through a first water pipe 12, and the second water tank 20 is connected to the brush 40 through a second water pipe 22. The cleaning liquid placed in both the first water tank 10 and the second water tank 20 is pure water, and the pure water is discharged from the low-pressure water pump 11 in the first water tank 10 through the first water pipe 12 into the second water tank 20; then discharged from the high-pressure water pump 21 in the second water tank 20 through the second water pipe 22, and the pure water then passes through the second water pipe 22 through the robot arm 30 and then through the channel 413 set inside the brush 40 to reach the nozzles 431 set at the upper and lower ends of the brush 40, and finally sprinkled on the surface of the upper polishing pad 51 and the lower polishing pad 61. Figure 2 As shown, the cleaning area of ​​the lower polishing disc 61 is an annular structure, and the structure of the upper polishing disc 51 is the same and is omitted here; the robot arm 30 drives the brush 40 to move horizontally between the upper polishing pad 51 and the lower polishing pad 61, that is, the brush 40 moves linearly from the outside to the inside along the radius of the lower polishing pad 61. The structural setting of the robot arm 30 is fully capable of driving the brush 40 to clean the upper polishing pad 51 and the lower polishing pad 61 without interference. Further, the nozzles 431 in the upper and lower end surfaces of the brush 40 are at a certain angle θ with the central axis of the robot arm 30. Preferably, the angle θ is 60°, as shown in FIG. Figure 3As shown, at this time, it is easier to clean the particles and solution on the surface of the polishing pad, and the cleaning effect is better.

[0043] In this embodiment, a low-pressure water pump 11 and a high-pressure water pump 21 are respectively arranged in the first water tank 10 and the second water tank 20. Both the low-pressure water pump 11 and the high-pressure water pump 21 are variable frequency water pumps from Danfoss. The water pressure of the first water tank 10 is 10-20 bar, and the water pressure of the second water tank 20 is 80-120 bar, thereby forming a large pressure difference between the first water tank 10 and the second water tank 20, so that the cleaning liquid enters the high-pressure water tank from the low-pressure water tank. After the discharged pure water cleaning liquid is pumped by the high-pressure water pump 21, the injection impulse is increased, and the SiO2 colloidal particles on the polishing pad can be easily washed away, and the stability of the pure water cleaning pressure can be ensured. The brush in the brush 40 is repeatedly cleaned, so that the cleaning effect of the brush 40 is better, thereby ensuring the cleanliness on the surface of the polishing pad, thereby improving the surface quality of the subsequent polished silicon wafers, and ensuring the polishing degree of the silicon wafers. Automatic control valves are provided on the low-pressure water pump 11 and the high-pressure water pump 21. Position sensors are provided on the first water tank 10 and the second water tank 20 for monitoring the height of the pure water cleaning liquid in each water tank. When the water level is higher than the maximum water level or lower than the minimum water level, the position sensor can provide information to an external controller (omitted in the figure) to prompt the operator to pay attention to the water level changes in the water tank. The position sensor is a commonly used monitoring structure in this field and will not be described in detail here.

[0044] The mechanical arm 30 includes a first mechanical arm 31 and a second mechanical arm 32. One end of the first mechanical arm 31 is hinged with the second mechanical arm 32. The other end of the first mechanical arm 31 is connected to the adapter 33. The second mechanical arm 32 is connected to the engine 34. The mechanical arm 30 is connected to the brush 40 through the adapter 33. The first mechanical arm 31 is a hollow cylindrical structure. A channel is provided in the middle of the adapter 33. The second water pipe 22 passes through the first mechanical arm 31 and the adapter 33 and is connected to the channel 413 in the brush 40, thereby completing the delivery of pure water cleaning liquid. The brush 40 is vertically arranged between the upper polishing pad 51 and the lower polishing pad 61. The engine 34 provides power to the second mechanical arm 32 so that the second mechanical arm 32 pulls the first mechanical arm 31, thereby driving the brush 40 to move horizontally and linearly.

[0045] Further, such as Figure 4-5As shown, the brush 40 includes a brush body 41, a brush assembly 42 located at the upper and lower ends of the brush body, a nozzle assembly 43, and a connecting assembly 44 located on the side of the brush body 41, wherein the brush assembly 42 directly contacts the polishing pad, the nozzle assembly 43 is at a certain distance from the surface of the polishing pad, the connecting assembly 44 is connected to the adapter 33 in the robot arm 30, and the connecting assembly 44 is fixedly arranged at the height center position of the housing 411. The channel 412 inside the brush body 41 is a T-shaped structure, one end of which is connected to the adapter 33, and the other two ends are connected to the nozzle 431. The brush assembly 42 and the nozzle assembly 43 both extend outward along the central axis of the brush body 41 and are arranged in parallel, and the nozzle assembly 43 is arranged in the brush assembly 42; the brush assembly 42 and the nozzle assembly 43 are both arranged perpendicular to the axis of the connecting assembly 44. After being discharged by the high-pressure water pump 21, the pure water cleaning liquid enters the nozzle assembly 43 through the second water pipe 22 through the channel 413 and is sprayed outward for cleaning. At the same time, the brush assembly 42 is synchronously cleaned horizontally with the nozzle 431, thereby cleaning the SiO2 colloidal particles on the polishing pad. The polishing pad rotates automatically, and the rotating polishing pad can clean the residual silicon powder and polishing liquid with the flushing of pure water. The brush 40 is controlled by the robot arm 30 to move horizontally, thereby completing the cleaning of the polishing pad.

[0046] Specifically, Figure 5 As shown, the brush body 41 is a circular columnar structure, including a shell 411 and a holder 412 disposed inside the shell 411. Two symmetrically arranged holders 412 are disposed inside the shell 411. The structure of the holder 412 is as shown in FIG. Figure 6 As shown, one end of the retainer 412 is embedded in the shell 411, and a gasket 414 is provided between the shell 411 and the retainer 412, and the outer wall of the retainer 412 is adapted to the inner wall of the shell 411; the other end of the retainer 412 is suspended and detachably connected to the nozzle 431 in the nozzle assembly 43, and the retainer 412 and the nozzle 431 are coaxially arranged on the central axis of the shell 411.

[0047] like Figure 7 As shown, the brush assembly 42 includes a brush seat 423 of a cylindrical structure, one end of which is embedded and fixed in the end surface of the housing 411, and at least two spring thrust pieces 416 are provided on the circumference of the position where the housing 411 and the brush seat 423 cooperate to prevent the brush assembly 42 from rotating, so that the brush assembly 42 is fixedly connected to the housing 411. The other end of the brush seat 423 is provided with a first brush head 421 and a second brush head 422, as shown in FIG. Figure 3As shown, the first brush head 421 and the second brush head 422 are evenly arranged in the same direction along the periphery of the brush seat 423, the first brush head 421 is arranged close to the outer wall of the brush seat 423, the second brush head 422 is placed on the inner side of the first brush head 421, and the first brush head 421 and the second brush head 422 are staggered; the diameter of the first brush head 421 is not less than the diameter of the second brush head 422, and this structural setting enables the first brush head 421 and the second brush head 422 to completely cover the upper end surface of the brush seat 423, so that there is no gap where the brush passes, and then the brush assembly 42 on each end side can clean the impurities and polishing liquid on the polishing pad, with a wide cleaning range and no dead corners. The double-sided brush assembly 42 can not only ensure the cleaning effect but also improve the cleaning efficiency, save cleaning time, ensure the cleanliness of the surface of the polishing pad, lay the foundation for the subsequent polishing of single crystal silicon wafers, and reduce production costs.

[0048] A retaining ring 415 is also provided between the connection position of the brush assembly 42 and the housing 411 to protect the cooperation between the brush assembly 42 and the housing 411. The brush assembly 42 is a consumable part. The brush assembly 42 and the housing 411 designed in this embodiment are detachably connected, so that the brush assembly 42 is easy to replace, and the brush head can be replaced at any time, thereby improving the service life of the brush. In this embodiment, the brush assembly 42 is fixedly connected to the housing 411. In the actual cleaning process, the upper polishing pad 51 and the lower polishing pad 61 are reversely rotated, and the brush 40 is perpendicular to the end faces of the upper polishing pad 51 and the lower polishing pad 61 and moves horizontally along the radius of the polishing pad. The brush assembly 42 and the nozzle 431 are fixed relative to the upper and lower polishing pads. The brush 40 moves horizontally with the robot arm 30 for cleaning. The brush assembly 42 with this structural arrangement can prevent the pure water cleaning liquid from splashing horizontally, so that the pure water is completely used for cleaning, which improves the utilization rate of the cleaning liquid, avoids the consumption of electric energy, and reduces production costs.

[0049] like Figure 7 and Figure 8 As shown, the nozzle assembly 43 is suspended at the central axis of the two ends of the housing 411 and connected to the connector 412, and is extended outward along the length direction of the brush body 41, and there is a gap between the nozzle assembly 43 and the brush assembly 42. Specifically, the nozzle assembly 43 includes a nozzle 431 for spraying water, a sleeve clamp 432 for clamping the nozzle 431, and an adjusting member 433 for adjusting the spray angle θ of the nozzle 431. The nozzle 431, the sleeve clamp 432 and the adjusting member 433 are coaxially arranged and sequentially arranged from the inside to the outside on the central axis of the housing 411. The nozzle 431 is a flat structure nozzle that is easily available on the market. The sleeve clamp 432 is adapted to the nozzle 431, and is configured and fixed on the end face of the housing 411 together with the nozzle 431. The flat nozzle 431 can not only increase the spraying area, but also increase the spraying wide angle, and is beneficial to the cleaning effect.

[0050] The adjusting member 433 includes an adjusting cap 4331 and an adjusting disk 4332. Figure 8 As shown, the outer wall of the adjusting cap 4331 is a hexagonal structure, embedded in the adjusting disk 4332, the central interior of the adjusting cap 4331 is provided with a threaded through hole that is threadedly matched with the outer wall of the upper end of the housing 411 and fixes the sleeve 432 therein, and the upper inner wall of the adjusting cap 4331 is adapted to the outer wall of the sleeve 432; the outer wall of the adjusting disk 4332 is circular, and a plurality of through holes are provided on the periphery of the adjusting disk 4332. After adjusting the angle of the nozzle 431, the adjusting cap 4331 is rotated to fix the nozzle 431, and then the through hole at the position of the nozzle 431 is fixed with bolts, so that the adjusting disk 4332 and the adjusting cap 4331 are tightened to completely fix the nozzle 431, and then the angle θ of the nozzle 431 spraying is fixed. In this embodiment, the upper and lower nozzles 431 are both at an angle of 60° with the central axis of the robot arm 30. The setting of this angle can increase the spraying area of ​​the nozzle 431 and ensure the impact force of the sprayed pure water. Preferably, the spraying angle of the nozzle 431 can be adjusted according to actual requirements, which is common knowledge in the art and will not be described in detail here.

[0051] The connecting assembly 44 includes a connecting plate 441 and a water inlet head 442. The connecting plate 441 is a rectangular structure. The side of the connecting plate 441 close to the shell 411 is adapted to the outer wall of the shell 411, and the side away from the shell 411 is a rectangular structure; the water inlet head 442 is placed in the connecting plate 441 and embedded in the side wall of the shell 411. The water inlet head 442 is provided with a through hole connected to the channel 13, and the connecting plate 441 and the water inlet head 442 are fixed to the shell 411 as a whole by symmetrically arranged screws.

[0052] The working process in this embodiment is as follows: the upper polishing surface 51 and the lower polishing surface 61 rotate synchronously in opposite directions, and the robot arm 30 drives the brush 40 to move horizontally from the outside to the inside along the radius of the lower polishing surface 61, thereby driving the pure water cleaning liquid from the first water tank 10 and the second water tank 20 to pass through the second water pipe 22 through the robot arm 30 and then through the channel 413 arranged inside the brush 40 to reach the nozzles 431 arranged at the upper and lower ends of the brush 40 for spraying, and finally sprinkle on the surfaces of the upper polishing pad 51 and the lower polishing pad 61 respectively; during the cleaning process, the brush assembly 42 and the nozzle 431 are fixed relative to the upper and lower polishing pads, and the brush assembly 42 and the nozzle 431 move horizontally and linearly with the robot arm 30, thereby completing the cleaning work of the upper polishing pad 51 and the lower polishing pad 61.

[0053] In this embodiment, the double-sided brush 40 is fully adapted to the polishing machine with the polishing disc structure arranged in the opposite position. The pure water cleaning liquid enters the high-pressure second water tank 20 from the low-pressure first water tank 10, thereby increasing the cleaning pressure of the cleaning liquid, ensuring the impact pressure and stability of the cleaning pressure of the cleaning liquid sprayed by the brush 40, and completely cleaning the SiO2 colloidal particles, residual silicon powder and polishing liquid on the polishing pad. At the same time, the design of high-pressure water can further reduce the cost of replacing the brush. The mechanical arm 30 can stably control the brush 40 to move in a straight line in the water along the radius of the polishing pad, ensuring that the brush assembly 42 and the nozzle 431 are fixed relative to the upper and lower polishing pads, and move horizontally with the mechanical arm 30 for cleaning, ensuring the cleaning effect. The double-layer staggered brush assembly 42 completely covers every position to be cleaned, ensuring that no gaps are missed during cleaning. The cooperation between high-pressure pure water cleaning and the brush assembly 42 makes the overall cleaning effect better, completely removing the SiO2 colloidal particles, residual silicon powder and polishing liquid on the polishing pad, ensuring the cleanliness of the polishing pad, improving the cleaning efficiency, and preventing subsequent silicon wafers from being scratched, thereby ensuring the polishing quality of the silicon wafers.

[0054] A method for cleaning a silicon wafer polishing pad, using the cleaning device as described above, comprises the following steps:

[0055] First, the pure water cleaning liquid is discharged from the low-pressure water pump 11 in the first water tank 10, enters the second water tank 20 through the first water pipe 12, and then is discharged from the high-pressure water pump 21 in the second water tank 20, passes through the robot arm 30 through the second water pipe 22 and enters the brush 40, and then is discharged from the high-pressure water pump 21 in the second water tank 20 and discharged through the second water pipe 22. The pure water then passes through the second water pipe 22 and passes through the robot arm 30 and then through the channel 413 arranged inside the brush 40 to reach the nozzles 431 arranged at the upper and lower ends of the brush 40 and are sprayed out, and finally sprinkled on the surfaces of the upper polishing pad 51 and the lower polishing pad 61 respectively.

[0056] During the cleaning process, the water pressure of the first water tank 10 is lower than that of the second water tank 20. Specifically, the water pressure of the first water tank 10 is 10-20 bar, and the water pressure of the second water tank 20 is 80-120 bar, which results in a large pressure difference between the first water tank 10 and the second water tank 20, and the pure water cleaning liquid enters the high-pressure water tank from the low-pressure water tank. After the discharged pure water cleaning liquid is pumped by the high-pressure water pump 21, the injection force is increased, and the SiO2 colloidal particles on the polishing pad can be easily washed clean, and the stability of the pure water cleaning pressure can be ensured. The brush in the brush 40 is repeatedly cleaned, so that the cleaning effect of the brush 40 is better, and the cleanliness on the surface of the polishing pad can be ensured, thereby improving the surface quality of the subsequent polished silicon wafers and ensuring the polishing degree of the silicon wafers. The upper polishing surface 51 and the lower polishing surface 61 rotate synchronously in opposite directions, and the robotic arm 30 drives the brush 40 to move horizontally from the outside to the inside along the radius of the lower polishing surface 61. At the same time, the brush assembly 42 and the nozzle 431 are fixed relative to the upper and lower polishing pads, and the brush assembly 42 and the nozzle 431 move horizontally and linearly with the robotic arm 30; when the brush 40 moves to the center position of the inner side of the polishing pad, the upper polishing plate 50 and the lower polishing plate 60 are separated, and the robotic arm 30 drives the brush 40 to withdraw to the initial position; then the upper polishing plate 50 and the lower polishing plate 60 are combined and the brush assemblies 42 at the upper and lower ends of the brush 40 are respectively in contact with the upper polishing surface 51 and the lower polishing surface 61, and then the robotic arm 30 is controlled to make the brush 40 continue to move from the outside to the inside along the radius of the lower polishing surface 61; the number of reciprocating times can be adjusted according to actual requirements, thereby completing the cleaning of the upper polishing pad 51 and the lower polishing pad 61.

[0057] The cleaning device designed by the present invention has a simple structure and is easy to control. It solves the technical problem of easy brush leakage during the existing polishing pad cleaning, and completely removes SiO2 colloidal particles, polishing liquid and silicon powder attached to the surface of the polishing pad. It has a high degree of automation, good cleaning effect and high cleaning efficiency.

[0058] The above embodiments of the present invention are described in detail, and the contents are only preferred embodiments of the present invention, and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A silicon wafer polishing pad cleaning device, characterized in that: The invention comprises a first water tank and a second water tank for storing cleaning liquid, a brush for cleaning an upper polishing pad and a lower polishing pad, and a mechanical arm for controlling the movement of the brush; the upper end surface of the brush contacts the upper polishing pad, and the lower end surface of the brush contacts the lower polishing pad; the first water tank is connected to the second water tank through a first water pipe, and the second water tank is connected to the brush through a second water pipe; the nozzles arranged at the upper and lower ends of the brush are at a certain angle to the axis of the mechanical arm; The central axis of the brush is perpendicular to the end surface of the upper polishing pad and the end surface of the lower polishing pad respectively; a T-shaped channel is provided inside the brush, the second water pipe passes through the mechanical arm and is connected to one end of the channel, and the nozzle is connected to the other two ends of the channel; A low-pressure water pump is provided in the first water tank, and a high-pressure water pump is provided in the second water tank; the cleaning liquid in the first water tank and the second water tank is pure water, and the pure water is discharged from the low-pressure water pump in the first water tank and enters the second water tank through the first water pipe; Then the water is discharged from the high-pressure water pump in the second water tank through the second water pipe, through the mechanical arm, and then through the channel arranged inside the brush to reach the nozzles arranged at the upper and lower ends of the brush, and finally sprinkled on the surface of the upper polishing pad and the lower polishing pad; The upper and lower end surfaces of the brush are both provided with nozzle assemblies, and the nozzle is placed in the middle of the nozzle assembly; the nozzle assembly is suspended at the central axis of the brush end surface and extends outward along the length direction of the brush; The nozzle assembly further comprises a sleeve clamp for fixing the nozzle and an adjusting member for adjusting the angle of the nozzle, wherein the nozzle, the sleeve clamp and the adjusting member are arranged in sequence from the inside to the outside; The upper and lower end surfaces of the brush are also provided with a brush assembly, the brush assembly is arranged in the same direction as the nozzle assembly, the brush assembly is placed outside the nozzle assembly, and there is a gap between the brush assembly and the nozzle assembly; The brush assembly comprises a brush seat of a cylindrical structure, one end of the brush seat is embedded and fixed in the end surface of the shell, and at least two spring thrust plates are arranged on the circumference of the position where the shell and the brush seat cooperate; the other end of the brush seat is provided with a first brush head and a second brush head, the first brush head and the second brush head are evenly arranged in the same direction along the periphery of the brush seat, the first brush head is arranged close to the outer wall of the brush seat, the second brush head is placed on the inner side of the first brush head, and the first brush head and the second brush head are staggered; the diameter of the first brush head is not less than the diameter of the second brush head; The adjusting member comprises an adjusting cap and an adjusting disk. The outer wall of the adjusting cap is a hexagonal structure and is embedded in the adjusting disk. A threaded through hole is provided in the center of the adjusting cap to cooperate with the thread of the outer wall of the upper end of the shell and fix the sleeve clamp therein. The upper inner wall of the adjusting cap is adapted to the outer wall of the sleeve clamp. The outer wall of the adjusting disk is circular and a plurality of through holes are provided on the periphery of the adjusting disk. After adjusting the angle of the nozzle, the adjusting cap is rotated to fix the nozzle and then fixed with bolts on the through hole at the nozzle position so that the adjusting disk and the adjusting cap cooperate with each other and are tightened to completely fix the nozzle, thereby fixing the spraying angle θ of the nozzle.

2. A silicon wafer polishing pad cleaning device according to claim 1, characterized in that: The angle is 60°.

3. A method for cleaning a silicon wafer polishing pad, characterized in that: Using the cleaning device as described in any one of claims 1 to 2, the steps include: the cleaning liquid sequentially passes through the first water tank and the second water tank through the second water pipe through the robot arm into the brush, and then sprays the upper polishing pad and the lower polishing pad through the nozzle respectively; During this process, the upper polishing pad and the lower polishing pad rotate synchronously in opposite directions, and the mechanical arm drives the brush to move horizontally along the radius of the lower polishing pad from outside to inside; The water pressure of the first water tank is lower than the water pressure of the second water tank.

4. A method for cleaning a silicon wafer polishing pad according to claim 3, characterized in that: The water pressure of the first water tank is 10-20 bar; the water pressure of the second water tank is 80-120 bar.

5. A method for cleaning a silicon wafer polishing pad according to claim 3 or 4, characterized in that: The brush assembly and the nozzle move horizontally and linearly relative to the lower polishing pad.

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