Wafer chucking centering mechanism based on magnetic force

Abstract

A magnetically based wafer clamping and centering mechanism includes: a base with a through hole; a guide post inserted into the through hole, the top surface of the guide post protruding to form a protrusion; a first magnet on the guide post, and a second magnet and a third magnet on the base; when the first magnet approaches the second magnet, the guide post rotates in a first direction, causing the protrusion on the guide post to abut against the edge of the wafer, thereby achieving wafer centering and clamping; when the first magnet approaches the third magnet, the guide post rotates in a second direction, causing the protrusion on the guide post to separate from the edge of the wafer, thereby achieving wafer release; this mechanism realizes the functions of wafer clamping, centering, and release, solving the problem that clamping disks in the prior art can only achieve a single function.

Description

Technical Field

[0001] This invention belongs to the field of wafer processing technology, specifically a wafer clamping and centering mechanism based on magnetic force. Background Technology

[0002] In the fabrication of 3D stacked chips (3D ICs), the morphology control of the wafer edge is directly related to the final yield of chip manufacturing, making it a critical process. To prevent microcracks or chipping at the wafer edge during subsequent processing, ultra-precision grinding is usually required to remove edge defects; this is known as wafer edge trimming.

[0003] Traditionally, a high-speed rotating diamond grinding wheel is used to grind around the wafer edge, creating a concave step structure for finishing. However, as 3D IC technology continues to advance towards higher precision, the processing accuracy of traditional methods is no longer sufficient to meet the requirements of advanced processes. An innovative process now employs a high-speed rotating grinding belt to grind and polish the wafer edge, achieving even higher precision finishing. For this new process, a wafer clamping device is required. Summary of the Invention

[0004] The purpose of this invention is to provide a wafer clamping and centering mechanism based on magnetic force to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A magnetically based wafer clamping and centering mechanism includes: A base, wherein a through hole is provided on the base; A guide post is inserted into the through hole, and the top surface of the guide post protrudes to form a protrusion. The guide post is provided with a first magnet, and the base is provided with a second magnet and a third magnet, with the second magnet and the third magnet being arranged vertically and offset from each other; When the first magnet approaches the second magnet, under the attraction between the first magnet and the second magnet, the guide post rotates in the first direction, so that the protrusion on the guide post abuts against the edge of the wafer, thereby achieving wafer centering and clamping. When the first magnet approaches the third magnet, the guide post rotates in the second direction under the attraction between the first magnet and the third magnet, causing the protrusion on the guide post to separate from the edge of the wafer, thereby releasing the wafer.

[0006] Preferably, both the second magnet and the third magnet are embedded in the inner wall of the through hole, with the second magnet located below the third magnet.

[0007] Preferably, a first compression spring is sleeved on the lower part of the guide post, and a limiting block is provided at the bottom of the guide post. One end of the first compression spring abuts against the limiting block, and the other end abuts against the bottom of the base.

[0008] Preferably, a first limiting ring is coaxially provided on the upper part of the guide post, and the first limiting ring is located above the base.

[0009] Preferably, the base is provided with a second limiting ring corresponding to the first limiting ring, the guide post passes through the second limiting ring and is coaxially arranged with the second limiting ring, the first limiting ring is located above the second limiting ring, the top of the second limiting ring has a limiting notch, the bottom of the first limiting ring protrudes to form a limiting part, and the limiting part extends into the limiting notch.

[0010] Preferably, a baffle is provided at the top of the protrusion.

[0011] Preferably, the number of through holes is at least three, which are evenly arranged around the wafer, and the number of guide pillars is the same as the number of through holes, and the two are arranged in a one-to-one correspondence.

[0012] Preferably, the base is provided with a detection element corresponding to the guide post along the transverse direction. The detection element includes a cylindrical shell, and a detection post is provided inside the cylindrical shell. The detection post extends into the through hole. A second compression spring is provided inside the cylindrical shell. One end of the second compression spring abuts against the cylindrical shell, and the other end abuts against the detection post, so that the detection post abuts against the guide post in the through hole. The guide post includes a sensing section. The outer diameter of the sensing section gradually increases or decreases from top to bottom. A sensing element is provided inside the cylindrical shell. The sensing element generates a corresponding electrical signal according to the degree to which the detection post extends out of the cylindrical shell.

[0013] Preferably, the sensing element includes a pressure sensor, which is disposed between the second compression spring and the cylindrical shell to detect the pressure of the second compression spring and determine the extent to which the detection column extends out of the cylindrical shell based on the pressure.

[0014] Preferably, the sensing element includes a plurality of metal contacts, which are disposed on the inner wall of the cylinder along the length direction of the detection column, and the electrical signal is generated when the detection column comes into contact with the metal contacts.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves wafer clamping, centering, and release functions by setting a first magnet on the guide post and a second and third magnet on the base, utilizing the attraction between the magnets to rotate the guide post. This solves the problem that existing clamping disks can only perform a single function. By setting a detection element on the base, which directly contacts the guide post and generates an electrical signal based on the position of the guide post, direct monitoring of the clamping status is achieved without the need for additional parts for detection, reducing costs and simplifying the structure. The entire mechanism has a simple structure, is inexpensive, and has strong functionality. When the wafer is raised, the space below the mechanism increases, facilitating clamping of the transmission equipment and reducing the cost of auxiliary mechanisms. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the wafer clamping and centering mechanism based on magnetic force in this embodiment; Figure 2 for Figure 1 Enlarged view of a portion of point A in the middle; Figure 3 This is a diagram showing the positional relationship between the guide post and the detection element in this embodiment; Figure 4 This is a schematic diagram of the detection component structure of a preferred embodiment in this example; Figure 5 This is a schematic diagram of the detection element structure of another preferred embodiment in this example; Figure 6 This is a diagram showing the positional relationship between the through hole and the second and third magnets in this embodiment; In the diagram: 1. Base; 101. Through hole; 2. Guide post; 201. Protrusion; 202. Sensing section; 203. Baffle; 204. Slope; 3. Detection component; 301. Cylinder shell; 302. Detection post; 303. Second compression spring; 304. Pressure sensor; 305. Metal contact; 4. First compression spring; 5. Limiting block; 6. First limiting ring; 601. Limiting part; 7. Second limiting ring; 701. Limiting notch; 8. Wafer; 9. First magnet; 10. Second magnet; 11. Third magnet. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1-3 as well as Figure 6As shown, this embodiment provides a wafer clamping and centering mechanism based on magnetic force, including a base 1, a guide post 2, a first magnet 9, a second magnet 10, and a third magnet 11.

[0019] A through hole 101 is provided on the base 1. The guide post 2 is inserted into the through hole 101 and is slidably connected to the through hole 101. The top surface of the guide post 2 protrudes to form a protrusion 201. A baffle 203 is provided on the top of the protrusion 201. The baffle 203 can block the wafer 8 from above when the wafer 8 is clamped, which improves the clamping stability and prevents the wafer 8 from falling off.

[0020] The guide post 2 is provided with a first magnet 9, and the base 1 is provided with a second magnet 10 and a third magnet 11. The second magnet 10 and the third magnet 11 are arranged vertically and staggered. Specifically, the second magnet 10 and the third magnet 11 are both embedded in the inner wall of the through hole 101, with the second magnet 10 located below the third magnet 11.

[0021] In this embodiment, the guide post 2 can rotate around its axis. When the guide post 2 rotates and the protrusion 201 on the guide post 2 gradually approaches the wafer 8 until it contacts the wafer 8, the rotation direction of the guide post 2 at this time is defined as the first direction; the second direction is the direction opposite to the first direction.

[0022] In this embodiment, in order to raise the guide column 2, a lifting assembly (not shown in the figure) can also be set. The lifting assembly is set below the guide column 2 to lift the guide column 2. The lifting assembly can include at least two lifting cylinders and a top plate. The at least two lifting cylinders work together to drive the top plate to rise and fall. When the top plate rises, it can lift all the guide columns 2 together from below the guide column 2, thereby driving the guide column 2 to rise. In this embodiment, other existing technical solutions can also be used to drive the guide column 2 to rise. For example, cylinders can be set directly below the guide column 2 to drive the guide column 2 to rise.

[0023] A first compression spring 4 is fitted at the lower part of the guide post 2, and a limiting block 5 is provided at the bottom of the guide post 2. One end of the first compression spring 4 abuts against the limiting block 5, and the other end abuts against the bottom of the base 1. This design allows the guide post 2 to automatically rebound after being subjected to external force, maintaining a stable clamping force, while also providing a certain buffering function to avoid damage to the wafer 8. The automatic rebound of the guide post 2 after being subjected to external force means that after the guide post 2 is raised by external force, when the external force disappears, the guide post 2 can automatically rebound and descend under the action of the first compression spring 4. For example, when the top plate of the lifting assembly rises, it lifts the guide post 2, and when the top plate descends, the guide post 2 descends again under the action of the first compression spring 4.

[0024] A first limiting ring 6 is coaxially provided on the upper part of the guide post 2, and the first limiting ring 6 is located above the base 1. The first limiting ring 6 restricts the degree of descent of the guide post 2.

[0025] The base 1 has a second limiting ring 7 corresponding to the first limiting ring 6. The guide post 2 passes through the second limiting ring 7 and is coaxially arranged with the second limiting ring 7. The first limiting ring 6 is located above the second limiting ring 7. A limiting notch 701 is formed at the top of the second limiting ring 7, and a limiting part 601 protrudes from the bottom of the first limiting ring 6, extending into the limiting notch 701. Through the cooperation of the first limiting ring 6 and the second limiting ring 7, the rotation angle of the guide post 2 can be limited, ensuring the accuracy of wafer 8 clamping and releasing.

[0026] The number of through holes 101 is at least three, which are evenly arranged around the wafer 8. The number of guide posts 2 is the same as the number of through holes 101, and the two are arranged in a one-to-one correspondence, meaning that one through hole 101 corresponds to one guide post 2. The even distribution of multiple guide posts 2 ensures that the wafer 8 is stably clamped and accurately aligned. In this embodiment, each guide post 2 is provided with a first magnet 9, and each through hole 101 is provided with a second magnet 10 and a third magnet 11.

[0027] The top surface of the guide post 2 forms a slope 204 that gradually decreases in height from the inside to the outside. In this embodiment, "from the inside to the outside" refers to the radial direction from the center point of the top surface of the guide post 2 outwards. This slope 204 design allows the guide post 2 to guide the wafer 8 more smoothly during alignment when it contacts the wafer 8, reducing the impact force on the edge of the wafer 8, protecting the wafer 8 from damage, and also reducing the contact area between the top surface of the guide post 2 and the edge of the wafer 8, thus reducing contamination of the wafer 8.

[0028] A detection element 3, corresponding to the guide post 2, is arranged laterally on the base 1. The detection element 3 includes a cylindrical shell 301. A detection post 302 is provided inside the cylindrical shell 301, extending into the through hole 101. A second compression spring 303 is provided inside the cylindrical shell 301, with one end abutting against the cylindrical shell 301 and the other end abutting against the detection post 302, so that the detection post 302 abuts against the guide post 2 in the through hole 101. The guide post 2 includes a sensing section 202, the outer diameter of which gradually increases or decreases from top to bottom. A sensor is provided inside the cylindrical shell 301, which generates a corresponding electrical signal according to the degree to which the detection post 302 extends out of the cylindrical shell 301. The second compression spring 303 presses the detection column 302 against the outer peripheral wall of the sensing section 202 of the guide column 2. The change in the outer diameter of the sensing section 202 from top to bottom causes a change in the degree to which the detection column 302 extends beyond the cylindrical shell 301. That is, as the guide column 2 rises and falls, the outer diameter of the sensing section 202 changes. Under the action of the second compression spring 303, the detection column 302 remains in contact with the outer peripheral wall of the sensing section 202. As the outer diameter of the sensing section 202 changes, the degree to which the detection column 302 extends beyond the cylindrical shell 301 also changes. The sensing element generates a corresponding response based on the degree to which the detection column 302 extends beyond the cylindrical shell 301. The electrical signal can be used to determine the extent to which the detection post 302 extends out of the cylindrical shell 301. The extent to which the detection post 302 extends out of the cylindrical shell 301 corresponds to the lifting and lowering status (height status) of the guide post 2. The lifting and lowering status of the guide post 2 corresponds to the clamping and releasing status of the wafer 8 (the height status of the guide post 2 corresponds to whether the first magnet 9 is attracted to the second magnet 10 or the third magnet 11. When the first magnet 9 is attracted to the second magnet 10, the wafer 8 is clamped; when the first magnet 9 is attracted to the third magnet 11, the wafer 8 is released). Therefore, the clamping and releasing status of the wafer 8 can be sensed by the set sensing element.

[0029] In a preferred embodiment, such as Figure 4As shown, the sensing element includes a pressure sensor 304, which is positioned between the second compression spring 303 and the cylindrical shell 301 to detect the pressure of the second compression spring 303. Based on the pressure, the degree to which the detection post 302 extends out of the cylindrical shell 301 is determined. By monitoring pressure changes, the position and movement state of the guide post 2 can be monitored in real time, thereby determining the clamping state of the wafer 8. When the wafer 8 is clamped, the first magnet 9 and the second magnet 10 are attracted together; the height of the guide post 2 at this time is defined as the clamping height. As the height of the guide post 2 gradually increases, the first magnet 9 slowly disengages from the contact with the second magnet 10 and gradually approaches the third magnet 11. When the first magnet 9 and the third magnet 11 are attracted together, the wafer 8 is released; the height of the guide post 2 at this time is defined as the release height. The pressure sensor 304 can continuously monitor the pressure of the second compression spring 303 in real time. The pressure of the spring 303 also reflects the degree to which the detection post 302 extends out of the cylinder shell 301 in real time. Therefore, the pressure sensor 304 can determine the height of the guide post 2 by detecting the pressure, thereby determining the clamping status of the wafer 8. The pressure is converted into an electrical signal by the pressure sensor 304, so the clamping status of the wafer 8 can be determined by the electrical signal. When determining the clamping status of the wafer 8 by the electrical signal of the pressure sensor 304, it is necessary to periodically calibrate the correspondence between the pressure of the second compression spring 303 and the height of the guide post 2 to avoid errors in judgment due to the pressure error of the second compression spring 303.

[0030] In another preferred embodiment, such as Figure 5As shown, the sensing element includes multiple metal contacts 305, which are arranged on the inner wall of the cylindrical shell 301 along the length of the detection post 302. An electrical signal is generated when the detection post 302 contacts the metal contacts 305. This design provides a digital position detection method that can more accurately determine the position of the detection post 302, thereby judging the movement state and height of the guide post 2. Specifically, as the detection post 302 gradually extends out of the cylindrical shell 301, the number of metal contacts 305 contacted by the detection post 302 decreases; as the detection post 302 gradually retracts into the cylindrical shell 301, the number of metal contacts 305 contacted by the detection post 302 increases. The degree to which the detection post 302 extends out of the cylindrical shell 301 can be judged by the number of metal contacts 305 contacted by the detection post 302, thereby judging the clamping state of the wafer 8. This judgment method is independent of the second compression spring 3. The influence of the elasticity change of 03; In order to realize that the detection column 302 contacts the metal contact 305 to generate an electrical signal, the detection column 302 can be set as a conductive material. When the detection column 302 contacts the metal contact 305, the detection column 302 can form an electrical connection with the metal contact 305, thereby generating an electrical signal. When the detection column 302 does not contact the metal contact 305, the detection column 302 and the metal contact 305 are in an open state. The electrical connection state between the detection column 302 and the metal contact 305 is used to determine whether the detection column 302 is in contact with the metal contact 305, thereby further determining the degree to which the detection column 302 extends out of the shell 301.

[0031] The working principle of the wafer 8 clamping and centering mechanism is as follows: When the first magnet 9 approaches the second magnet 10, under the attraction between the first magnet 9 and the second magnet 10, the guide post 2 rotates in the first direction, causing the protrusion 201 on the guide post 2 to abut against the edge of the wafer 8, thereby achieving centering and clamping of the wafer 8. When the first magnet 9 approaches the third magnet 11, under the attraction between the first magnet 9 and the third magnet 11, the guide post 2 rotates in the second direction, causing the protrusion 201 on the guide post 2 to separate from the edge of the wafer 8, thereby releasing the wafer 8.

[0032] In this embodiment, the second magnet 10 is disposed below the third magnet 11, and the two are offset from each other; When the first magnet 9 and the second magnet 10 are attracted together, the wafer 8 is in a clamped state. At this time, if it is necessary to release the wafer 8, external force is required to raise the guide post 2. During the raising of the guide post 2, the first magnet 9 rises together with the guide post 2. The first magnet 9 gradually detaches from the contact with the second magnet 10 and gradually approaches the third magnet 11 until the first magnet 9 is attracted to the third magnet 11 under the action of magnetic force. Because the second magnet 10 and the third magnet 11 are misaligned, when the first magnet 9 and the third magnet 11 are attracted together, the guide post 2 will rotate, causing the protrusion 201 to move away from the wafer 8, thus releasing the wafer 8.

[0033] When the first magnet 9 and the third magnet 11 are attracted, the wafer 8 is in a released state. At this time, if it is necessary to clamp the wafer 8, the external force applied to the guide post 2 needs to be removed, so that the guide post 2 is lowered under the action of the first compression spring 4. During the descent of the guide post 2, the first magnet 9 is lowered along with the guide post 2. The first magnet 9 gradually disengages from the contact with the third magnet 11 and gradually approaches the second magnet 10 until the first magnet 9 is attracted to the second magnet 10 under the action of magnetic force. Because the second magnet 10 and the third magnet 11 are misaligned, when the first magnet 9 is attracted to the second magnet 10, it will drive the guide post 2 to rotate, so that the protrusion 201 approaches the wafer 8 and contacts the edge of the wafer 8. The protrusions 201 on the multiple guide posts 2 work together to clamp the wafer 8.

[0034] This wafer 8 clamping and centering mechanism controls the rotation direction of the guide post 2 through the attraction between magnets. It features a simple structure and convenient operation, enabling precise centering and reliable clamping of the wafer 8, thus improving the efficiency and quality of wafer 8 processing. This design effectively reduces the risk of wafer 8 damage during processing, ensuring high precision and high quality.

[0035] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A wafer clamping and centering mechanism based on magnetic force, characterized in that, include: A base, wherein a through hole is provided on the base; A guide post is inserted into the through hole, and the top surface of the guide post protrudes to form a protrusion. The guide post is provided with a first magnet, and the base is provided with a second magnet and a third magnet, with the second magnet and the third magnet being arranged vertically and offset from each other; When the first magnet approaches the second magnet, under the attraction between the first magnet and the second magnet, the guide post rotates in the first direction, so that the protrusion on the guide post abuts against the edge of the wafer, thereby achieving wafer centering and clamping. When the first magnet approaches the third magnet, the guide post rotates in the second direction under the attraction between the first magnet and the third magnet, causing the protrusion on the guide post to separate from the edge of the wafer, thereby releasing the wafer.

2. The wafer clamping and centering mechanism based on magnetic force as described in claim 1, characterized in that, Both the second magnet and the third magnet are embedded in the inner wall of the through hole, with the second magnet located below the third magnet.

3. The wafer clamping and centering mechanism based on magnetic force as described in claim 1, characterized in that, A first compression spring is sleeved on the lower part of the guide post, and a limiting block is provided at the bottom of the guide post. One end of the first compression spring abuts against the limiting block, and the other end abuts against the bottom of the base.

4. The wafer clamping and alignment mechanism based on magnetic force as described in claim 1, characterized in that, The upper part of the guide post is coaxially provided with a first limiting ring, which is located above the base.

5. A wafer clamping and centering mechanism based on magnetic force as described in claim 4, characterized in that, The base is provided with a second limiting ring corresponding to the first limiting ring. The guide post passes through the second limiting ring and is coaxially arranged with the second limiting ring. The first limiting ring is located above the second limiting ring. A limiting notch is opened at the top of the second limiting ring. The bottom of the first limiting ring protrudes to form a limiting part, and the limiting part extends into the limiting notch.

6. A wafer clamping and centering mechanism based on magnetic force as described in claim 1, characterized in that, A baffle is provided at the top of the protrusion.

7. A wafer clamping and centering mechanism based on magnetic force as described in claim 1, characterized in that, The number of through holes is at least three, which are evenly arranged around the wafer. The number of guide pillars is the same as the number of through holes, and the two are arranged in a one-to-one correspondence.

8. A wafer clamping and centering mechanism based on magnetic force as described in claim 1, characterized in that, The base is provided with a detection element corresponding to the guide post along a transverse direction. The detection element includes a cylindrical shell, and a detection post is provided inside the cylindrical shell. The detection post extends into the through hole. A second compression spring is provided inside the cylindrical shell. One end of the second compression spring abuts against the cylindrical shell, and the other end abuts against the detection post, so that the detection post abuts against the guide post in the through hole. The guide post includes a sensing section. The outer diameter of the sensing section gradually increases or decreases from top to bottom. A sensing element is provided inside the cylindrical shell. The sensing element generates a corresponding electrical signal according to the degree to which the detection post extends out of the cylindrical shell.

9. A wafer clamping and centering mechanism based on magnetic force as described in claim 8, characterized in that, The sensing element includes a pressure sensor, which is disposed between the second compression spring and the cylindrical shell to detect the pressure of the second compression spring and determine the extent to which the detection column extends out of the cylindrical shell based on the pressure.

10. A wafer clamping and centering mechanism based on magnetic force as described in claim 8, characterized in that, The sensing element includes multiple metal contacts, which are arranged on the inner wall of the cylinder along the length of the detection column. When the detection column comes into contact with the metal contacts, it generates the electrical signal.

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