Wafer cleaning device

Abstract

A wafer cleaning device disclosed by the present invention comprises a box body, a wafer supporting mechanism, a wafer scrubbing mechanism and a liquid supply assembly, the wafer supporting mechanism comprises a roller used for bearing a wafer and driving the wafer to rotate and a mounting seat, the mounting seat is used for fixing the roller and the box body, a sealing assembly is arranged between the mounting seat and the box body, and the sealing assembly is used for sealing the mounting seat and the box body. The sealing assembly comprises a sealing gasket, an outer pressing ring and an inner pressing ring, the sealing gasket and the installation base are fixed through the inner pressing ring, the sealing gasket and the box body are fixed through the outer pressing ring, and the inner pressing ring is located on the inner side of the outer pressing ring.

Description

[0001] This application is a divisional application of the invention patent application with application number 202310369232.3 filed on April 7, 2023. Technical Field

[0002] The present invention relates to the technical field of chemical mechanical polishing post-processing, and in particular to a wafer cleaning device. Background Art

[0003] In the semiconductor industry, wafer surface cleanliness is a critical factor affecting semiconductor device reliability. During wafer manufacturing processes, such as deposition, plasma etching, photolithography, and electroplating, contamination and / or particles can be introduced onto the wafer surface, reducing wafer surface cleanliness and resulting in low semiconductor device yield. Therefore, multiple surface cleanings are required during wafer manufacturing to remove contaminants such as metal ions, atoms, organic matter, and particulates adhering to the wafer surface.

[0004] The scrubbing module used to clean wafers is equipped with rollers that drive the wafers to rotate or follow the wafers. The rollers are in direct contact with the wafers. In actual production, it is found that the edges of the wafers are difficult to clean. After scrubbing, contaminants still remain on the edges of the wafers, which are difficult to completely remove. Summary of the Invention

[0005] An embodiment of the present invention provides a wafer cleaning device, which aims to solve at least one of the technical problems existing in the prior art.

[0006] An embodiment of the present invention provides a wafer cleaning device, comprising: a box, a wafer supporting mechanism, a wafer brushing mechanism and a liquid supply assembly, wherein the wafer supporting mechanism comprises a roller and a mounting seat for carrying the wafer and driving the wafer to rotate, the mounting seat is used to fix the roller to the box, a sealing assembly is arranged between the mounting seat and the box, the sealing assembly comprises a sealing gasket, an outer pressure ring and an inner pressure ring, the inner pressure ring fixes the sealing gasket to the mounting seat, the outer pressure ring fixes the sealing gasket to the box, and the inner pressure ring is located on the inner side of the outer pressure ring.

[0007] In one embodiment, the upper portion of the outer pressure ring has a water retaining structure.

[0008] In one embodiment, the water retaining structure includes a water retaining eave extending outward from the outer peripheral edge of the outer pressure ring and a water guide groove formed between the water retaining eave and the box body.

[0009] In one embodiment, the water retaining eaves are a half-moon shaped structure that gradually narrows from high to low.

[0010] In one embodiment, the water retaining eaves extend obliquely from the inside to the outside toward the roller.

[0011] In one embodiment, the lower portion of the outer pressure ring has a drainage structure.

[0012] In one embodiment, the drainage structure is a gap at the bottom of the outer pressure ring.

[0013] In one embodiment, the outer area of ​​the sealing gasket is located between the outer pressure ring and the box body, and the sealing gasket and the box body are sealed by fixing the outer pressure ring.

[0014] In one embodiment, the sealing gasket and the inner pressure ring are sleeved on the outer periphery of the mounting seat, and the lock nut with internal threads is threadedly connected to the portion of the mounting seat with external threads to press the inner pressure ring and the sealing gasket against the mounting seat.

[0015] The beneficial effects of the embodiments of the present invention include: achieving the sealing function of the wafer support mechanism and improving the pollution discharge capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, but these drawings are only exemplary and do not limit the scope of protection of the present invention, among which:

[0017] Figure 1 FIG2 shows a wafer processing device provided by an embodiment of the present invention;

[0018] Figure 2 A wafer cleaning device according to an embodiment of the present invention is shown;

[0019] Figures 3 to 5 A sealing assembly provided by an embodiment of the present invention is shown;

[0020] Figures 6 to 8 A sealing assembly provided by another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0021] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein. It should be understood that, unless otherwise specified, for ease of understanding, the following descriptions of the specific embodiments of the present invention are all based on the description of the relevant equipment, devices, components, etc. in their original static natural state without external control signals and driving forces.

[0022] In addition, it should be noted that the terms used in this application to indicate directions, such as front, back, up, down, left, right, top, bottom, front, back, horizontal, vertical, etc., are only for the convenience of description to help understand the relative position or direction, and are not intended to limit the orientation of any device or structure.

[0023] In order to illustrate the technical solution of the present invention, the following description will be made with reference to the accompanying drawings and in combination with embodiments.

[0024] In this application, chemical mechanical polishing is also referred to as chemical mechanical planarization, and wafer is also referred to as chip, silicon chip, base plate or substrate, etc., and their meanings and actual functions are equivalent.

[0025] like Figure 1 As shown, a wafer processing device 100 provided by an embodiment of the present invention includes: a cache module 110 , two processing modules 120 and a front-end module 150 .

[0026] The cache module 110 may be provided with multiple layers, and the multi-layer cache module 110 may cache multiple wafers at the same time.

[0027] The processing modules 120 are used to polish wafers. The two processing modules 120 can work independently. Each processing module 120 can include: a polishing unit 121, a first robot 122, a transfer unit 123, a second robot 124 and a plurality of cleaning units 125.

[0028] like Figure 1As shown, the wafer processing equipment 100 includes four polishing units 121, which can be chemical mechanical polishing units. When the wafer processing equipment 100 is working, the wafer can enter any one or more of the four polishing units 121 for polishing. After completing one or more steps of polishing, the wafer is sent back to the transfer unit 123. Figure 1 As shown, each polishing unit 121 may include a polishing plate 211 , a polishing head 212 and a loading and unloading platform 213 . The loading and unloading platforms 213 of the two polishing units 121 are both disposed adjacent to the second robot 124 .

[0029] like Figure 2 As shown, before polishing begins, the second robot 124 moves the wafer to the loading and unloading platform 213. The polishing head 212 loads the wafer from the loading and unloading platform 213 and then moves radially above the polishing plate 211. During the chemical mechanical polishing process, the polishing head 212 presses the wafer against the polishing pad covering the surface of the polishing plate 211. The size of the polishing pad is larger than the size of the wafer to be polished, for example, 1.2 times or more of the wafer size, thereby ensuring uniform polishing of the wafer. The polishing head 212 rotates and reciprocates radially along the polishing plate 211, gradually polishing away the surface of the wafer in contact with the polishing pad. Simultaneously, the polishing plate 211 rotates, and a polishing liquid supply device sprays polishing liquid onto the surface of the polishing pad. Under the chemical action of the polishing liquid, the relative movement of the polishing head 212 and the polishing plate 211 causes the wafer to rub against the polishing pad, resulting in polishing. A polishing slurry composed of submicron or nano-abrasive particles and a chemical solution flows between the wafer and the polishing pad. Driven by the centrifugal force of the polishing pad's rotation and transmission, the polishing slurry is evenly distributed, forming a thin film of liquid between the wafer and the polishing pad. The chemical components in the liquid react with the wafer, converting insoluble substances into soluble ones. These chemical reactants are then removed from the wafer surface by micromechanical friction of the abrasive particles and carried away by the flowing liquid. This alternating process of chemical film formation and mechanical film removal removes surface material, achieving global planarization. During polishing, a dresser is used to condition and activate the polishing pad's surface topography. This dresser removes impurities remaining on the polishing pad's surface, such as abrasive particles in the polishing slurry and waste material dislodged from the wafer surface. It also smoothes out surface deformation caused by grinding, ensuring consistent pad topography throughout the polishing process and maintaining a stable polishing removal rate. After polishing is completed, the polishing head 212 absorbs the wafer and places it on the loading and unloading platform 213 . The second robot 124 takes the wafer from the loading and unloading platform 213 and transports the wafer to the cleaning unit 125 .

[0030] like Figure 1As shown, a transfer module 130 may be formed between the polishing units 121 of the two processing modules 120, and the transfer units 123 may be disposed within the transfer module 130. The transfer unit 123 may transfer wafers between a first robot 122 and a second robot 124. The first robot 122 moves between the buffer module 110 and the transfer unit 123, and between the transfer unit 123 and the cleaning unit 125. The second robot 124 is used to transfer wafers to and from the polishing unit 121.

[0031] like Figure 1 As shown, an arrangement space 140 is left between the cleaning units 125 of the two processing modules 120 , and the two first manipulators 122 and the cache module 110 are arranged in the arrangement space 140 .

[0032] like Figure 1 As shown, each cleaning unit 125 may include: multiple cleaning modules 251, drying modules 252, vertical buffer modules 253 and flip modules 254, and the cleaning modules 251, drying modules 252, vertical buffer modules 253 and flip modules 254 are arranged side by side. Among them, the cleaning module 251 can use a variety of methods such as brushing, rotating, megasonic and / or spraying to achieve wafer cleaning. The drying module 252 can use a variety of methods such as rotating and / or pulling to achieve wafer drying. It is understandable that the number of cleaning modules 251 can also be other numbers and is not limited to Figure 1 shown.

[0033] like Figure 1 As shown, each cleaning unit 125 may further include: a third robot 255 and a fourth robot 256 , the third robot 255 moves above the cleaning module 251 and the vertical cache module 253 , and the fourth robot 256 moves above the cleaning module 251 , the drying module 252 and the flipping module 254 .

[0034] like Figure 2 As shown, an embodiment of the present invention provides a wafer cleaning device 1 for cleaning wafers W, comprising: a box 10, a wafer supporting mechanism 20, a wafer scrubbing mechanism 30 and a liquid supply component 40, etc.

[0035] like Figure 2 As shown, a process chamber is formed inside the box 10 to provide an environment for processing wafers w.

[0036] like Figure 2 As shown, the wafer scrubbing mechanism 30 includes two cleaning brushes, a cleaning brush driving mechanism and a liquid inlet mechanism.

[0037] Two cleaning brushes, one on the front and one on the back of the wafer w, roll and scrub the surface of the wafer w, rolling in opposite directions. The first and second cleaning brushes are placed on the front and back of the wafer w to be cleaned, respectively. They roll around their axes to contact and scrub the surface of the wafer w to be cleaned. The cleaning brushes are cylindrical rollers made of a highly absorbent material, such as polyvinyl alcohol (PVA).

[0038] like Figure 2 As shown, a liquid inlet mechanism connected to one end of the cleaning brush continuously supplies liquid to the cleaning brush, keeping the cleaning brush moist. The cleaning brush is made of a porous material capable of absorbing large amounts of liquid. The liquid can be an acidic or alkaline solution, or deionized water. The liquid inlet mechanism is connected to the liquid inlet end of the cleaning brush to fill the cleaning brush with liquid. After being filled with liquid, the cleaning brush becomes soft and can be used to clean wafers W. Therefore, the cleaning brush must be kept filled with liquid at all times during the cleaning process.

[0039] like Figure 2 As shown, the brush drive mechanism is used to drive two brushes toward each other, clamping wafer w at a certain angle for rolling scrubbing. The brushes can move horizontally to move away from or toward wafer w. When the brushes are away from wafer w, a certain gap is left between them, allowing the wafer handling robot to grasp and remove the cleaned wafer w. When the brushes move toward wafer w, they contact and clean the wafer w.

[0040] like Figure 2 As shown, the liquid supply assembly 40 is used to supply cleaning liquid to the surface of the wafer w, specifically to the upper area of ​​the wafer w above the cleaning brush. The cleaning liquid is supplied at an angle of 5° to 30° relative to the surface of the wafer w. The liquid supply assembly 40 is connected to a fluid source via a delivery pipeline.

[0041] like Figure 2 As shown, the wafer support mechanism 20 is used to support, position, and rotate the wafer w in a vertical plane. The wafer support mechanism 20 is fixed to the housing 10 and extends into the process chamber. The wafer w to be cleaned is supported by the wafer support mechanism 20 and rotates in a vertical plane around a horizontal axis.

[0042] In one embodiment, the wafer support mechanism 20 includes a plurality of rollers 21 for supporting and rotating the wafer. The plurality of rollers 21 may be two driving wheels and a driven wheel positioned below the wafer w for support. The two driving wheels act as a drive, utilizing a motor to rotate the wafer w. The driven wheel is positioned between the two driving wheels to provide auxiliary support and speed measurement.

[0043] like Figures 2 to 8As shown, the wafer support mechanism 20 passes through the side wall of the box 10 and extends into the box 10. A portion of the wafer support mechanism 20 is located inside the box 10 for supporting the wafer, and another portion of the wafer support mechanism 20 is located outside the box 10 for connecting to a drive mechanism located outside the box 10 or being fixed to the box 10, thereby forming a gap at the point where the box 10 is passed. The presence of this gap allows the roller 21 to adjust its position within a certain range to better accommodate the wafer. The roller 21 is used to abut the wafer and drive the wafer to rotate. During cleaning, the wafer is confined in the slot of the roller 21 and rotates synchronously with the roller 21.

[0044] The mounting base 23 is used to secure the roller 21 to the housing 10. The mounting base 23 extends through the sidewall of the housing 10 and into the interior of the housing 10. The portion of the mounting base 23 located outside the housing 10 is connected to the housing 10 via a support member. Specifically, the mounting base 23 is secured to the support member using screws, and the support member and the housing 10 are each secured to the same base using screws. A gap is formed between the mounting base 23 and the housing 10. This gap is sealed by a sealing assembly 24.

[0045] The roller 21 is connected to the mounting base 23 via a rotating shaft 22. The rotating shaft 22 is rotatably mounted within the mounting base 23. One end of the rotating shaft 22 is connected to the roller 21 to drive the roller 21 in rotation. A bearing is provided on the rotating shaft 22. The mounting base 23 is mounted on the outer periphery of the rotating shaft 22, and the mounting base 23 and the rotating shaft 22 are connected via a bearing. When the roller 21 is the driving wheel, a drive mechanism is connected to the rotating shaft 22 to drive the rotating shaft 22 in rotation.

[0046] like Figure 3 As shown, a sealing assembly 24 is provided between the mounting base 23 and the housing 10. The sealing assembly 24 is fixed to the mounting base 23 and the housing 10, respectively, and is used to seal the gap between the mounting base 23 and the housing 10. The sealing assembly 24 includes a sealing gasket 25, an outer pressure ring 28, and an inner pressure ring 26. The inner pressure ring 26 fixes the sealing gasket 25 to the mounting base 23, and the outer pressure ring 28 fixes the sealing gasket 25 to the housing 10. The inner pressure ring 26 is located inside the outer pressure ring 28.

[0047] like Figure 3 As shown, the sealing gasket 25 is annular and is arranged around the mounting seat 23. The sealing gasket 25 is made of elastic material. The outer pressure ring 28 and the inner pressure ring 26 are both annular.

[0048] In one embodiment, the outer area of ​​the sealing gasket 25 is located between the outer pressure ring 28 and the side wall of the box body 10. A number of screw holes are provided around the outer pressure ring 28. The outer pressure ring 28 is fixed to the side wall of the box body 10 by screws, so that the outer area of ​​the annular sealing gasket 25 is pressed and fixed to the side wall of the box body 10 by the outer pressure ring 28, that is, the outer pressure ring 28 and the sealing gasket 25 are pressed and sealed with the box body 10.

[0049] In one embodiment, a sealing gasket 25 and an inner pressure ring 26 are sleeved around the outer circumference of the mounting base 23. A circular hole is formed in the center of the sealing gasket 25. The externally threaded portion of the mounting base 23 passes through the circular hole of the sealing gasket 25 and then through the inner pressure ring 26. The inner region of the sealing gasket 25 is located between the inner pressure ring 26 and the mounting base 23. A lock nut 27 with an internal thread is threadedly connected to the externally threaded portion of the mounting base 23, thereby tightening the inner pressure ring 26 and the sealing gasket 25 against the mounting base 23. From the inside of the housing 10 toward the sidewall of the housing 10, the lock nut 27, the inner pressure ring 26, the sealing gasket 25, and the mounting base 23 are arranged in this order. The lock nut 27 is screwed in, thereby pressing the inner pressure ring 26 and the sealing gasket 25 against the front end surface of the mounting base 23. Once the external pressure ring 28 and the inner pressure ring 26 are secured, the gap between the housing 10 and the mounting base 23 is sealed by the sealing gasket 25.

[0050] like Figure 3 and Figure 4 As shown, in one embodiment of the present invention, a gap is formed between the inner pressure ring 26 and the outer pressure ring 28 to accommodate the flexible deformation of the sealing gasket 25, facilitating the position adjustment of the roller 21. When the contact position between the roller 21 and the wafer is adjusted, the size of the gaps between the mounting base 23 and the housing 10 changes, causing the sealing gasket 25 to flexibly deform and the size of the gap between the inner pressure ring 26 and the outer pressure ring 28 to change accordingly.

[0051] like Figures 3 to 5 As shown, in one embodiment of the present invention, a water retaining structure is provided on the upper portion of the outer pressure ring 28. During cleaning, some of the liquid flowing downward from the upper portion of the housing 10 may contact the sealing gasket 25 from the upper edge and become contaminated. By providing a water retaining structure on the upper portion of the outer pressure ring 28, the liquid flowing from above can be blocked, preventing the contaminated liquid from further contaminating the roller 21 and affecting the wafer cleaning effect.

[0052] In one embodiment, the water retaining structure includes a water retaining eave 281 extending outward from the outer peripheral edge of the outer pressure ring 28, and a water guide groove 282 formed between the water retaining eave 281 and the housing 10. In one embodiment, the water retaining eave 281 can be formed by extending outward from the entire edge of the outer pressure ring 28. In another embodiment, the water retaining eave 281 can be formed by extending outward from a portion of the edge of the outer pressure ring 28. The water retaining eave 281 can extend vertically upward or tilted upward, with the tilt direction tilting from the inside to the outside toward the roller 21. It should be noted that the "inside" and "outside" referred to in this application document are all referenced to the rotation axis 22 as the center. "Inside" refers to the area close to the rotation axis 22, and "outside" refers to the area away from the rotation axis 22. For example, the outer pressure ring 28, inner pressure ring 26, inward, outward, and from the inside to the outside are all referenced to this. The top and bottom in the text are referenced to the directions drawn in the accompanying drawings of the specification.

[0053] like Figures 3 to 5 In the example shown, the water retaining eave 281 is formed by extending upward from the outer edge of the upper half of the outer pressure ring 28 away from the housing 10. The water retaining eave 281 extends obliquely from the inside to the outside toward the roller 21. The water retaining eave 281 can block liquid coming from above. Accordingly, a water guide groove 282 is formed between the water retaining eave 281 and the housing 10, or between the water retaining eave 281 and the sealing gasket 25, and is surrounded by the water retaining eave 281 and the circumference of the outer pressure ring 28. Because the bottom surface of the water guide groove 282 is an arc-shaped shape with a high center and low sides, the water guide groove 282 can collect the liquid blocked by the water retaining eave 281 and drain it downward from both sides. In other words, under the combined action of the water retaining eave 281 and the water guide groove 282, contaminated liquid can flow downward along the outer circumference of the outer pressure ring 28, preventing contaminants from contaminating the roller 21 and the wafer.

[0054] like Figure 4 and Figure 5 As shown, in one embodiment, the water retaining eaves 281 are a half-moon shaped structure that gradually narrows from high to low. In other words, the width of the water retaining eaves 281 gradually decreases from top to bottom.

[0055] In this embodiment, when the liquid coming from the peripheral direction of the roller 21 contacts the sealing gasket 25, the contaminated liquid can enter the water guide groove 282 formed between the semi-lunar water retaining eaves 281 on the top of the outer pressure ring 28 and the side wall of the box body 10, and then the liquid containing pollutants will be guided to flow toward both sides along the outer peripheral surface of the outer pressure ring 28. By setting up a water retaining structure, the liquid accumulated above the outer pressure ring 28 is prevented from being transferred from the front of the outer pressure ring 28 to the roller 21, thereby preventing the roller 21 and the wafer from being contaminated.

[0056] like Figures 6 to 8As shown, in another embodiment of the present invention, the lower portion of the outer pressure ring 28 has a drainage structure 283 for facilitating liquid drainage and preventing excessive liquid from accumulating at the bottom and contaminating the adjacent roller 21. Figure 7 and Figure 8 In the example shown, the drainage structure 283 is a notch at the bottom of the outer pressure ring 28. Alternatively, in another embodiment, the drainage structure 283 can also be a groove located on the bottom surface of the outer pressure ring 28, which can also allow liquid to drain.

[0057] like Figure 7 and Figure 8 As shown, in one embodiment, the drainage structure 283 is a notch at the bottom of the outer pressure ring 28. The inner bottom of the outer pressure ring 28 is provided with an arc-shaped inclined surface at the edge of this notch to guide the liquid downward. Due to the structure of the outer pressure ring 28 in this embodiment, liquid from other directions can only contact the surface of the sealing gasket 25 in the process chamber through the gap between the inner pressure ring 26 and the outer pressure ring 28. Liquid entering this gap is confined to the annular semi-enclosed space between the outer pressure ring 28 and the inner pressure ring 26 and flows out of the drainage structure 283 along the bottom of the annular semi-enclosed space. For example, liquid flowing from the top of the outer pressure ring 28 to the inner circumference of the outer pressure ring 28 or liquid flowing between the outer pressure ring 28 and the inner pressure ring 26 will enter the annular semi-enclosed space along the inner circumference of the outer pressure ring 28 or the outer circumference of the inner pressure ring 26. The accumulated liquid is drained downward and then flows out of the drainage structure 283. This prevents the accumulation of dirty water from contaminating the roller 21.

[0058] In summary, the outer pressure ring 28 and the inner pressure ring 26 cooperate with each other to guide the liquid flowing through the sealing gasket 25 to flow downward, thereby cutting off the path of the liquid that contacts the sealing gasket 25 and is contaminated by it to propagate to the roller 21, blocking the propagation path of contaminants between the contamination risk components and the wafers to be cleaned, thereby solving the problem of the cleaned wafers being randomly contaminated by dirty water from the sealing gasket 25 when the wafers are vertically brushed, significantly improving the cleanliness near the edge of the wafer, and greatly improving the effect and stability of the cleaning process.

[0059] The drawings in this specification are schematic diagrams that assist in illustrating the concepts of the present invention and schematically illustrate the shapes of the various components and their interrelationships. It should be understood that in order to clearly illustrate the structures of the various components of the embodiments of the present invention, the drawings are not drawn to the same scale, and the same reference numerals are used to represent the same parts in the drawings.

[0060] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A wafer cleaning device, characterized in that: include: A box body, a wafer support mechanism, a wafer scrubbing mechanism and a liquid supply assembly. The wafer support mechanism includes a roller and a mounting seat for carrying the wafer and driving the wafer to rotate. The mounting seat is used to fix the roller to the box body. A sealing assembly is provided between the mounting seat and the box body. The sealing assembly includes a sealing gasket, an outer pressure ring and an inner pressure ring. The inner pressure ring fixes the sealing gasket to the mounting seat, and the outer pressure ring fixes the sealing gasket to the box body. The inner pressure ring is located on the inner side of the outer pressure ring. The upper part of the outer pressure ring has a water retaining structure, which prevents the liquid flowing down from the upper part of the box from flowing to the roller through the sealing gasket when cleaning the wafer, so as to avoid contamination of the wafer.

2. The wafer cleaning device according to claim 1, wherein: The water retaining structure includes a water retaining eave extending outward from the outer peripheral edge of the outer pressure ring and a water guide groove formed between the water retaining eave and the box body.

3. The wafer cleaning device according to claim 2, wherein: The water retaining eaves are a half-moon shaped structure that gradually narrows from high to low.

4. The wafer cleaning device according to claim 2, wherein: The water retaining eaves extend obliquely from the inside to the outside toward the roller.

5. The wafer cleaning device according to claim 1, wherein: The lower part of the outer pressure ring is provided with a drainage structure.

6. The wafer cleaning device according to claim 5, wherein: The drainage structure is a gap at the bottom of the outer pressure ring.

7. The wafer cleaning device according to claim 1, wherein: The outer area of ​​the sealing gasket is located between the outer pressure ring and the box body, and the sealing gasket and the box body are sealed by fixing the outer pressure ring.

8. The wafer cleaning device according to claim 1, wherein: The sealing gasket and the inner pressure ring are sleeved on the outer periphery of the mounting seat, and the lock nut with internal threads is connected to the part of the mounting seat with external threads through threads to press the inner pressure ring and the sealing gasket against the mounting seat.

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