Wafer clamping mechanism and wafer cleaning and spin-drying method

Abstract

The invention discloses a wafer clamping mechanism and a wafer cleaning and spin-drying method, and the wafer clamping mechanism comprises a chuck; the base can rotate relative to the chuck around the central axis of the base; the bearing parts are arranged on the bases and are provided with bearing surfaces capable of being in contact with the bottom surfaces of the wafers, and the bearing parts of the multiple bases are matched to be used for horizontally or approximately horizontally bearing the wafers; the clamping part is arranged on the base and is provided with a first clamping surface which can be in contact with the side surface of the wafer; the base is provided with a bearing position and a clamping position, and at the bearing position, the bearing surface is in contact with the bottom surface of the wafer, and the first clamping surface is not in contact with the wafer; the base rotates relative to the chuck, and when the base is switched from the bearing position to the clamping position, the contact position of the bearing surface and the bottom surface of the wafer gradually approaches the center of the wafer until the first clamping surfaces of the plurality of clamping parts abut against the side surface of the wafer to clamp the wafer, and the wafer is separated from the bearing surface. The wafer clamping device does not depend on the rotating speed or the centrifugal force effect, and stable and reliable clamping of the wafer can be achieved within the whole rotating speed range.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit chip manufacturing technology, and in particular relates to a wafer clamping mechanism and a wafer cleaning and drying method. Background Technology

[0002] With the continuous advancement of semiconductor manufacturing technology, the importance of ultra-clean processes is constantly increasing. The requirements for the cleanliness of wafer surfaces after cleaning and drying are also continuously rising in chemical mechanical planarization (CMP) equipment.

[0003] In chemical mechanical planarization (CMP) equipment, after the wafer cleaning process, a final cleaning and drying process is required. Specifically, the wet wafer is fixed on a chuck, and the chuck rotates the wafer, using centrifugal force to dry it. During this process, it is crucial not only to ensure the wafer remains firmly fixed on the chuck during high-speed rotation but also to ensure that the liquid distributed on the wafer surface can be discharged unimpeded under centrifugal force. Otherwise, liquid residue on the wafer surface will affect the process results. In particular, the wafer-bearing surface of the chuck, which is in direct contact with the back of the wafer, is more prone to liquid accumulation.

[0004] Chinese patent CN118943073B discloses a "Wafer Chuck and Semiconductor Equipment," which has the following technical features: A. The switching between the release and clamping positions requires the synchronous movement of a lifting mechanism and a rotating mechanism. The lifting mechanism rises to limit the chuck, and the rotating drive mechanism moves to create an angle difference between the chuck and the housing, thereby allowing the jaws to rotate and achieve the limiting position; B. When the wafer is in the release and clamping positions, the platform supporting the wafer is always in contact with the wafer; C. The drive component in this patent serves as both the power source for wafer rotation and the power source for switching between the clamping and release positions. Its structure is relatively complex.

[0005] Chinese patent CN119803007A discloses a "Wafer Rotary Drying Mechanism," which reveals that during the centrifugal rotary drying process, water droplets and stains easily remain at and near the contact point between the back of the wafer and the support surface, forming a high-pressure capillary area. This leads to the problem that the accumulated liquid in this area cannot be spun out and is difficult to remove during the wafer spin-drying process. The solution is to install a centrifugal drainage tank between the support surface and the clamping surface. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a wafer clamping mechanism and a wafer cleaning and spin-drying method. The mechanism has a simple structure, provides stable clamping, and achieves excellent wafer cleaning results. It solves the problem in the prior art where the bearing surface comes into contact with the bottom surface of the wafer during the spin-drying process, and the liquid cannot be discharged smoothly at the contact point, resulting in liquid residue.

[0007] The technical solution adopted by this invention to solve its technical problem is: a wafer clamping mechanism, comprising, Chuck; The bases, numbering at least three, are spaced apart circumferentially along the chuck and can rotate relative to the chuck about their own central axis; A support portion, provided on the base, has a bearing surface that can contact the bottom surface of the wafer, and the support portions of multiple bases cooperate to support the wafer horizontally or nearly horizontally. A clamping part is provided on the base and has a first clamping surface that can contact the side of the wafer; The base has a receiving position and a clamping position. In the receiving position, the bearing surface contacts the bottom surface of the wafer, and the first clamping surface does not contact the wafer. When the base rotates relative to the chuck and switches from the receiving position to the clamping position, the contact position between the bearing surface and the bottom surface of the wafer gradually moves closer to the direction of the wafer center until the first clamping surface of the multiple clamping parts abuts against the side of the wafer to clamp the wafer, and the wafer is released from the bearing surface.

[0008] Furthermore, the inclination angle of the bearing surface relative to the horizontal plane is 0-15°; or, the inclination angle of the bearing surface relative to the horizontal plane is 3-15°.

[0009] Furthermore, the first clamping surface is vertically arranged, and the clamping part also includes a second clamping surface that forms an angle with the first clamping surface, the second clamping surface having an inclination angle of 30-70° relative to the horizontal plane.

[0010] Furthermore, the thickness of the wafer is S, the height of the junction of the first clamping surface and the second clamping surface is H1, the height of the bottom surface of the wafer is H2 when it is in the receiving position, and the height of the contact point between the bottom surface of the wafer and the bearing surface when the wafer is detached from the bearing surface is H3. The absolute value of the difference between H1 and H2 is less than or equal to 0.5S, the absolute value of the difference between H3 and H2 is less than or equal to 1.5S, and the absolute value of the difference between H3 and H2 is greater than the absolute value of the difference between H1 and H2.

[0011] Furthermore, there are six bases, which are evenly spaced along the circumference of the chuck; a drive unit is connected to the bottom of each base.

[0012] Furthermore, the supporting portion and the clamping portion are disposed on both radial sides of the base.

[0013] Furthermore, the base also has an over-clamping position, and the base can rotate in the same direction to sequentially switch from the receiving position to the clamping position and the over-clamping position.

[0014] Furthermore, the support portion is cylindrical, with its outer wall vertically protruding to form a bearing portion, the bearing surface is located on the top surface of the bearing portion, and the support portion also forms a guide surface, which is located above the bearing surface.

[0015] This invention also discloses a wafer cleaning and spin-drying method, which is based on the aforementioned wafer clamping mechanism and includes the following steps: The chuck remains stationary, and the base rotates relative to the chuck until it is in the receiving position; The transfer device places the wafer horizontally or nearly horizontally on the bearing surface of multiple base supports, at which point the clamping part does not contact the wafer; Multiple bases rotate relative to the chuck, the clamping part approaches the wafer, and the side of the wafer slides against the second clamping surface. The contact position between the bottom surface of the wafer and the bearing surface gradually moves towards the center of the wafer until the first clamping surface abuts against the side of the wafer, and the wafer is removed from the bearing surface. The wafer is firmly held by multiple clamping parts, and the chuck rotates at high speed to dry the wafer; The chuck stops rotating, and the transfer device removes the dried wafer.

[0016] Furthermore, the process includes the following steps before the transfer device places the wafer onto the carrier surface: The base switches from the receiving position to the over-clamping position to determine whether a wafer has been placed on the wafer clamping mechanism. If no wafer has been placed, the base rotates in the opposite direction relative to the chuck to the receiving position.

[0017] Furthermore, the process by which the transfer device places the wafer horizontally or nearly horizontally on the support surfaces of the multiple base supports includes the following sub-steps: The transfer device picks up the wafer from the previous station and moves it horizontally above the chuck, with the center of the wafer coinciding with or nearly coinciding with the center of the chuck. The transfer device is located below the wafer and lowers the wafer vertically until the bottom surface of the wafer contacts the support surface. The transfer device continues to descend 5-8mm, and after detaching from the wafer, it moves horizontally out from below the wafer.

[0018] The beneficial effects of this invention are: 1) Compared to the passive clamping of wafers relying on centrifugal force in the prior art, which only provides sufficient clamping force when the rotation speed reaches a specific threshold, and is prone to clamping force attenuation due to insufficient rotation speed during the rotation start-stop phase, easily causing wafer displacement or even surface damage, this invention actively achieves the rotation of the base before rotation begins, uses the clamping part to achieve stable clamping of the wafer, and drives the base to rotate through an independent drive unit to apply clamping force to the wafer. After clamping is completed, high-speed rotation is used to spin the wafer dry. It does not rely on rotation speed or centrifugal force effect, and can achieve stable and reliable clamping of the wafer throughout the entire rotation speed range—including conditions where centrifugal force is insufficient during start-up and deceleration—fundamentally avoiding This invention addresses the risks of wafer surface scratches and even wafer drop caused by fluctuations in clamping force; 2) Existing technologies present a contradiction: to reduce the requirements for wafer placement accuracy, the support surface needs to have a larger size and a smaller horizontal tilt angle, while to achieve better process performance and suppress capillary effects, the support surface needs to be smaller and the tilt angle larger; these two mutually restrictive requirements are difficult to optimize in a single chuck structure. The clamping mechanism proposed in this invention separates the clamping surface and the bearing surface on both sides of the base, achieving functional separation: one side is dedicated to support, and the other side is responsible for clamping. This layout decouples the two types of functional requirements, ensuring both the tolerance of wafer placement and effectively suppressing capillary effects, thus balancing process performance and operational reliability; 3) Utilizing the base's... Rotation enables the switching between the wafer receiving position and the clamping position. Through the independent arrangement of the bearing surface and the first clamping surface, the substrate can rotate a small angle (typically 3-10°) to detach the bearing surface from the wafer in the clamping position, allowing liquid on the top and bottom surfaces of the wafer to drain unimpeded under centrifugal force. 4) In integrated circuit manufacturing processes, silicon wafers, as typical disk-shaped substrates, undergo multiple precision processes such as etching, cleaning, and inspection. In these processes, the wafer requires a dedicated clamping device for reliable fixation and support. The core requirements are: providing sufficient mechanical constraint stability while strictly avoiding physical contact with the upper and lower process surfaces of the wafer to prevent contamination or damage and ensure the electrical integrity of the device. In terms of performance and yield, the clamping mechanism proposed in this invention combines process compatibility and operational functionality: on the one hand, it can support the wafer when interacting with upstream and downstream equipment; on the other hand, it can apply stable clamping during processing, thus taking into account the wafer's positioning accuracy, process safety, and surface integrity in the entire process; 5) It has good consistency in clamping wafers and is suitable for clamping wafers of different sizes; 6) The presence of a wafer in the clamping mechanism can be determined by the rotation angle of the base, or by determining whether the wafer's placement is normal. When there is no wafer on the clamping mechanism, the rotation angle is greater than the angle when clamping a wafer normally. At this time, the base is in the over-clamping position, which can determine that there is no wafer on the clamping device or that the wafer is in a dropped or tilted state. Attached Figure Description

[0019] Figure 1 This is a perspective view of the wafer clamping mechanism and wafer mating provided by the present invention.

[0020] Figure 2 This is a perspective view of the wafer clamping mechanism provided by the present invention.

[0021] Figure 3 A perspective view of the base provided by the present invention.

[0022] Figure 4 This is a front view of the base provided by the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of the bearing surface part of the present invention.

[0024] Figure 6 Top view of the base and wafer mating of the present invention Figure 1 At this point, it is in the receiving position.

[0025] Figure 7 Top view of the base and wafer mating of the present invention Figure 2 It is currently in the clamping position.

[0026] Figure 8 A simplified diagram showing the positions of the base provided by the present invention in the receiving position, clamping position, and over-clamping position.

[0027] Figure 9 A schematic diagram illustrating the fit between the support portion, clamping portion, and wafer provided by the present invention. Figure 1 At this time, the base is in the receiving position.

[0028] Figure 10 A schematic diagram illustrating the fit between the support portion, clamping portion, and wafer provided by the present invention. Figure 2 At this time, the base is in the clamping position.

[0029] Figure 11 The diagram shows different states of the wafer clamping mechanism provided by the present invention, where a is the receiving position, b and d are the clamping positions, and c is the state in which the wafer is about to be removed from the bearing surface.

[0030] Among them, 1-chuck, 2-base, 20-protrusion, 21-drive unit, 3-support part, 30-bearing part, 31-bearing surface, 32-guide surface, 4-clamping part, 41-first clamping surface, 42-second clamping surface, 43-sloping surface, 5-wafer, 51-wafer side surface, 52-wafer bottom surface. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] like Figure 1 , Figure 2 As shown, a wafer clamping mechanism includes a circular chuck 1 and at least three bases 2 spaced apart along the circumference of the chuck 1. The bases 2 are disc-shaped and their top surfaces are flush with the top surface of the chuck 1 after being clamped in the mounting holes of the chuck 1. The bases 2 can rotate relative to the chuck 1 around their own central axis. In this embodiment, a drive unit 21 is connected to the bottom of each base 2, thereby using the drive unit 21 to realize the rotation of the base 2 relative to the chuck 1.

[0033] like Figure 3 As shown, each base 2 is provided with a protruding post 20 that is concentric and coaxial with the base 2. The protruding post 20 is provided with a supporting part 3 and a clamping part 4, and the supporting part 3 and the clamping part 4 are provided on both radial sides of the protruding post 20.

[0034] The support portion 3 is cylindrical, with its outer wall vertically protruding to form a support portion 30. The top of this support portion 30 forms a support surface 31 that can contact the bottom surface 52 of the wafer. The support portions 3 of the multiple bases 2 cooperate with each other to support the wafer 5 horizontally or nearly horizontally. The inclination angle of the support surface 31 relative to the horizontal plane is 0-15°, meaning the support surface 31 can be horizontal or inclined. In this embodiment, the support surface 31 is inclined; preferably, the inclination angle of the support surface 31 relative to the horizontal plane is 3-15°. Figure 5 The β angle is 3-15°, preferably 7°.

[0035] The clamping part 4 is also cylindrical, having a vertically arranged first clamping surface 41 and a second clamping surface 42 at an angle to the first clamping surface 41. The first clamping surface 41 is used to contact the wafer side surface 51, that is, by applying pressure to the wafer side surface 51, frictional force in the height direction is generated. The first clamping surfaces 41 of the multiple clamping parts 4 cooperate with each other to firmly clamp the wafer 5 from the side surface, preventing the wafer 5 from falling downwards. The second clamping surface 42 has an inclination angle of 30-70° relative to the horizontal plane, that is, as shown in the figure. Figure 4As shown, the second clamping surface 42 extends obliquely from top to bottom and from inside to outside, with an oblique angle α of 30-70°, preferably 60°. During the rotation of the base 2, the second clamping surface 42 first contacts the wafer side surface 51. At this time, the first clamping surface 41 has not yet fully abutted against the wafer side surface 51. Under the action of the clamping force, the wafer 5 gradually rises along the second clamping surface 42 until the first clamping surface 41 is in close contact with the wafer side surface 51. Of course, the clamping part 4 may only have the first clamping surface 41 and not the second clamping surface 42. To prevent the wafer 5 from flying upwards during rotation, a slope 43 is also provided at the top of the first clamping surface 41. The slope 43 plays a protective role and does not contact the wafer 5 during clamping.

[0036] The base 2 has a receiving position and a clamping position. In the receiving position, the bearing surface 31 contacts the bottom surface 52 of the wafer, or in other words, the wafer 5 is placed horizontally or nearly horizontally on the bearing surface 31. At this time, the first clamping surface 41 does not contact the wafer 5. Figure 6 As shown; the base 2 rotates relative to the chuck 1, so as to Figure 1 Taking the direction shown as an example, when the base 2 rotates counterclockwise relative to the chuck 1, and the base 2 switches from the receiving position to the clamping position, the contact position between the bearing surface 31 and the bottom surface 52 of the wafer gradually changes. Specifically, it moves towards the direction closer to the center of the wafer 5 until the first clamping surface 41 of the multiple clamping parts 4 abuts against the side surface 51 of the wafer, thereby firmly clamping the wafer 5. At this time, the wafer 5 has also detached from the bearing surface 31. Figure 7 As shown.

[0037] Compared to existing technologies, this invention achieves horizontal support and stable clamping of the wafer 5 with only a simple structure such as the base 2; moreover, this invention implements the support and clamping of the wafer 5 in two separate components, as follows: Figure 9 As shown, the support part 3 only needs to perform the function of horizontally supporting the bottom surface 52 of the wafer, and does not need to clamp the side surface 51 of the wafer, as... Figure 10As shown, the clamping part 4 only needs to provide a stable clamping function for the side surface 51 of the wafer, and does not need to horizontally support the bottom surface 52 of the wafer. Therefore, in order to avoid the problem that the horizontality of the wafer 5 is difficult to guarantee under multi-point support due to an excessively large tilt angle of the bearing surface 31 of the supporting part 3, the tilt angle of the bearing surface 31 of the supporting part 3 can be as small as possible. This is because there is no need to consider the situation where the bottom surface 52 of the wafer cannot be effectively spun dry due to capillary effect caused by an excessively small tilt angle. Making the tilt angle of the bearing surface 31 small can ensure that the wafer 5 is placed as horizontally as possible, and also avoid the wafer 5 being unable to be effectively clamped due to tilting. In addition, in this invention, the base 2 rotates relative to the chuck 1 to achieve a stable clamping of the wafer 5. That is to say, the wafer 5 is already firmly clamped before the chuck 1 rotates with the wafer 5 at high speed. Unlike the prior art, which uses the high-speed rotation of the chuck to firmly clamp the wafer under the action of centrifugal force, this invention does not require centrifugal force to clamp the wafer, and therefore the situation of the wafer sliding before the chuck rotates at high speed will not occur. Furthermore, since the wafer 5 is separated from the support part 3 when the clamping part 4 clamps the wafer 5, the space below the wafer 5 is open, which will not cause the phenomenon of high-pressure capillary liquid accumulation when the wafer 5 is placed for spin drying, and the cleaning effect of the wafer 5 is better.

[0038] To facilitate the placement of the wafer 5 onto the support surface 31, a guide surface 32 is provided on the support portion 3. This guide surface 32 extends obliquely from top to bottom and from the inside to the outside, and is located above the support surface 31. Specifically, the lower end of the guide surface 32 connects with the highest point of the support surface 31. Thus, the wafer 5 can slide down along the guide surface 32 onto the support surface 31.

[0039] To achieve better integration between the wafer clamping mechanism and upstream and downstream wafer transfer devices, such as Figure 11 As shown, the height of the junction between the first clamping surface 41 and the second clamping surface 42 is H1. When in the receiving position, the height of the wafer bottom surface 52 is H2. When the wafer 5 is detached from the bearing surface 31, the height of the contact point between the wafer bottom surface 52 and the bearing surface 31 is H3. Let the thickness of the wafer 5 be S. Then |H1-H2|≤0.5S, |H3-H2|≤1.5S, and |H3-H2|>|H1-H2|. More specifically, |H1-H2|≤0.5mm, |H3-H2|≤1mm. Therefore, the height of the wafer 5 remains essentially unchanged before and after clamping. Furthermore, the process of switching from the receiving position to the clamping position does not cause the wafer 5 to become unstable, ensuring that the wafer 5 will not tilt or fall off. At the same time, it ensures that the wafer 5 can smoothly detach from the bearing surface 31 when it is securely clamped.

[0040] In this embodiment, there are six bases 2, which are evenly spaced along the circumference of the chuck 1, thus providing better stable clamping of the wafer 5 and dispersing the clamping force on the wafer 5 more effectively. This also meets the clamping requirements of wafers of different sizes. Of course, in other embodiments, the number of bases 2 can be any number from 3 to 9, and there is no specific limitation.

[0041] Base 2 also has a clamping position, such as Figure 8 As shown, the base 2 rotates in the same direction, taking the direction shown in the figure as an example, it rotates clockwise, and can switch from the receiving position to the clamping position and the over-clamping position in sequence.

[0042] A wafer cleaning and spin-drying method, based on the aforementioned wafer clamping mechanism, includes the following steps: S1, chuck 1 is stationary, base 2 rotates relative to chuck 1 to the receiving position; S2, the base 2 switches from the receiving position to the over-clamping position to determine whether a wafer 5 has been placed on the wafer clamping mechanism. If no wafer 5 has been placed, the base 2 rotates in the opposite direction to the chuck 1 to the receiving position; if it is determined that a wafer 5 has been placed, the error reporting program is started. S3, the transfer device places the wafer 5 horizontally or nearly horizontally on the bearing surface 31 of the multiple base 2 support parts 3, with the wafer 5 in line contact with the bearing surface 31, at which time the clamping part 4 does not contact the wafer 5; in this embodiment, the transfer device is a robotic arm structure in the prior art; Specifically, step S3 above includes the following sub-steps: S31, the transfer device picks up the wafer 5 from the previous station and moves the wafer 5 horizontally above the chuck 1, with the center of the wafer 5 coinciding with or nearly coinciding with the center of the chuck 1; S32, the transfer device is located below the wafer 5. After receiving the signal that the base 2 has rotated in the opposite direction to the receiving position relative to the chuck 1, it carries the wafer 5 vertically down until the bottom surface 52 of the wafer contacts the bearing surface 31. S33, the transfer device continues to descend 5-8mm, and the transfer device after detaching from wafer 5 moves horizontally out from below wafer 5; S4, multiple bases 2 rotate relative to chuck 1, multiple clamping parts 4 approach wafer 5 together, and the side surface 51 of wafer slides against the second clamping surface 42. The contact position between the bottom surface 52 of wafer and the bearing surface 31 gradually moves towards the center of wafer 5 until the first clamping surface 41 abuts against the side surface of wafer 5 and wafer 5 is separated from the bearing surface 31. Before the second clamping surface 42 contacts wafer 5, wafer 5 undergoes a slight displacement in the vertical direction, with a drop height of about 1mm. S5, the wafer 5 is firmly held by multiple clamping parts 4, and the chuck 1 rotates at high speed, with a speed of up to 3000 RPM, to achieve the spin drying of the wafer 5; S6, chuck 1 stops rotating, and the transfer device removes the dried wafer 5; Specifically, step S6 above includes the following sub-steps: S61, the multiple bases 2 rotate in opposite directions relative to the chuck 1, switching from the clamping position to the receiving position; S62, the transfer device moves horizontally from 5-8mm below wafer 5 to directly below wafer 5; S63, after reaching the predetermined position, the transfer device rises until it contacts the bottom surface 52 of the wafer, picks up the wafer 5 and continues to rise until the bottom surface 52 of the wafer is completely higher than the base 2, and the wafer 5 moves to the next station with the transfer device.

[0043] The above specific embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A wafer clamping mechanism, characterized in that: include, Chuck (1); The base (2) is at least three in number, which are arranged circumferentially along the chuck (1) and can rotate relative to the chuck (1) about their own central axis; The support portion (3) is provided on the base (2) and has a bearing surface (31) that can contact the bottom surface (52) of the wafer. The support portions (3) of the multiple bases (2) cooperate to support the wafer (5) horizontally or nearly horizontally. The clamping part (4) is provided on the base (2) and has a first clamping surface (41) that can contact the side of the wafer (5). The base (2) has a receiving position and a clamping position. When in the receiving position, the bearing surface (31) contacts the bottom surface (52) of the wafer, and the first clamping surface (41) does not contact the wafer (5). When the base (2) rotates relative to the chuck (1) and the base (2) switches from the receiving position to the clamping position, the contact position between the bearing surface (31) and the bottom surface (52) of the wafer gradually moves closer to the center of the wafer (5) until the first clamping surface (41) of the multiple clamping parts (4) abuts against the side surface (51) of the wafer to clamp the wafer (5), and the wafer (5) is removed from the bearing surface (31).

2. The wafer clamping mechanism according to claim 1, characterized in that: The inclination angle of the bearing surface (31) relative to the horizontal plane is 0-15°; or, the inclination angle of the bearing surface (31) relative to the horizontal plane is 3-15°.

3. The wafer clamping mechanism according to claim 1 or 2, characterized in that: The first clamping surface (41) is vertically arranged, and the clamping part (4) further includes a second clamping surface (42) that forms an angle with the first clamping surface (41), and the second clamping surface (42) has an inclination angle of 30-70° relative to the horizontal plane.

4. The wafer clamping mechanism according to claim 3, characterized in that: The thickness of the wafer (5) is S, the height of the junction of the first clamping surface (41) and the second clamping surface (42) is H1, the height of the bottom surface (52) of the wafer is H2 when it is in the receiving position, and the height of the contact point between the bottom surface (52) of the wafer and the bearing surface (31) when the wafer (5) is detached from the bearing surface (31) is H3. The absolute value of the difference between H1 and H2 is less than or equal to 0.5S, the absolute value of the difference between H3 and H2 is less than or equal to 1.5S, and the absolute value of the difference between H3 and H2 is greater than the absolute value of the difference between H1 and H2.

5. The wafer clamping mechanism according to claim 1, characterized in that: The number of bases (2) is six, which are evenly spaced along the circumference of the chuck (1); the bottom of the base (2) is connected to a drive unit (21).

6. The wafer clamping mechanism according to claim 1, characterized in that: The supporting part (3) and the clamping part (4) are arranged on both radial sides of the base (2).

7. The wafer clamping mechanism according to claim 1, characterized in that: The base (2) also has an over-clamping position. The base (2) rotates in the same direction and can be switched sequentially from the receiving position to the clamping position and the over-clamping position.

8. The wafer clamping mechanism according to claim 1, characterized in that: The support part (3) is cylindrical, and its outer wall protrudes vertically to form a support part (30). The support surface (31) is located on the top surface of the support part (30). The support part (3) also forms a guide surface (32), which is located above the support surface (31).

9. A wafer cleaning and spin-drying method, based on the wafer clamping mechanism as described in claim 3 or 4, characterized in that: Includes the following steps, The chuck remains stationary, and the base rotates relative to the chuck until it is in the receiving position; The transfer device places the wafer horizontally or nearly horizontally on the bearing surface of multiple base supports, at which point the clamping part does not contact the wafer; Multiple bases rotate relative to the chuck, the clamping part approaches the wafer, and the side of the wafer slides against the second clamping surface. The contact position between the bottom surface of the wafer and the bearing surface gradually moves towards the center of the wafer until the first clamping surface abuts against the side of the wafer, and the wafer is removed from the bearing surface. The wafer is firmly held by multiple clamping parts, and the chuck rotates at high speed to dry the wafer; The chuck stops rotating, and the transfer device removes the dried wafer.

10. The wafer cleaning and drying method according to claim 9, characterized in that: The process includes the following steps before the transfer device places the wafer onto the carrier surface. The base switches from the receiving position to the over-clamping position to determine whether a wafer has been placed on the wafer clamping mechanism. If no wafer has been placed, the base rotates in the opposite direction relative to the chuck to the receiving position.

11. The wafer cleaning and drying method according to claim 9, characterized in that: The process by which the transfer device places the wafer horizontally or nearly horizontally on the support surfaces of multiple base supports includes the following sub-steps. The transfer device picks up the wafer from the previous station and moves it horizontally above the chuck, with the center of the wafer coinciding with or nearly coinciding with the center of the chuck. The transfer device is located below the wafer and lowers the wafer vertically until the bottom surface of the wafer contacts the support surface. The transfer device continues to descend 5-8mm, and after detaching from the wafer, it moves horizontally out from below the wafer.

Images