Adjustment method of double-sided polishing machine

Abstract

This invention provides a method for adjusting a double-sided polishing machine. The method includes the following steps: providing a double-sided polishing machine, the machine comprising an upper plate and a lower plate, with an inner gear ring and an outer gear ring positioned between the upper and lower plates, and polishing cloth covering the opposing surfaces of the upper and lower plates; measuring the inner and outer gap distances between the upper and lower plates to obtain the gap difference; placing a set of grinding wheels between the upper and lower plates; simultaneously rotating the upper and lower plates, causing the grinding wheels to thin the polishing cloth through rotation, thereby reducing the gap difference. This step adjusts the linear velocity of the inner and outer edge apexes of the upper and lower plates by adjusting the rotational speeds of the outer gear ring, inner gear ring, lower plate, and upper plate. A higher linear velocity corresponds to a greater thinning rate of the polishing cloth, thus adjusting the thickness difference between the inner and outer surfaces of the polishing cloth. The above method adjusts the removal amount of the polishing disc on the inner and outer surfaces of the polishing cloth by adjusting the rotational speeds of the outer gear ring, inner gear ring, lower plate, and upper plate, and corrects the thickness difference of the polishing disc by adjusting the thickness difference of the polishing cloth.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment, and more particularly to an adjustment method for a double-sided polishing machine. Background Technology

[0002] Double-sided polishing machines are commonly used in semiconductor equipment. The polishing machine consists of an upper plate and a lower plate, with a carrier between them. The upper and lower plates are made of metal discs, internally circulated with cooling water. The expansion and contraction of the upper and lower plates are controlled by adjusting the temperature of the cooling water according to the principle of thermal expansion and contraction of metals. Internal and external gear rings are used between the upper and lower plates to provide driving force for the carrier. The carrier is used to support the silicon wafer, ensuring that the wafer does not slip out during rotary processing.

[0003] The machine has four actively rotating components. The upper and lower plates rotate relative to each other clockwise and counterclockwise, respectively. Internal and external gear rings drive the carrier to revolve around the center of the equipment while simultaneously rotating on its own axis. During this rotation, the silicon wafer clamped in the center is polished. Experiments have shown that the thickness of the polished wafers produced by the machine is inconsistent between the center and the edges. One reason for this problem is the inconsistent gap between the upper and lower polishing plates. Therefore, how to adjust the consistency of the gap between the upper and lower polishing plates to improve the consistency of the polished wafer thickness is a problem that needs to be solved by existing technology. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an adjustment method for a double-sided polishing machine that can compensate for the gap difference of the polishing disc by the thickness difference of the polishing cloth, thereby improving the thickness consistency of the polishing sheet.

[0005] To address the aforementioned problems, this invention provides an adjustment method for a double-sided polishing machine, comprising the following steps: providing a double-sided polishing machine, the double-sided polishing machine comprising an upper plate and a lower plate, with an inner gear ring and an outer gear ring disposed between the upper plate and the lower plate, and polishing cloth covering the opposing surfaces of the upper plate and the lower plate; measuring the inner gap distance and the outer gap distance between the upper plate and the lower plate to obtain the gap difference value; placing a set of grinding wheels between the upper plate and the lower plate; simultaneously rotating the upper plate and the lower plate, so that the grinding wheels thin the polishing cloth by rotation to reduce the gap difference value. This step adjusts the linear velocity of the inner and outer edge apexes of the upper plate and the lower plate by adjusting the rotation speed of the outer gear ring, the inner gear ring, the lower plate, and the upper plate. A higher linear velocity corresponds to a greater polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth.

[0006] Optionally, the thickness difference between the inner and outer edges of the polishing cloth can be adjusted by changing the rotational speed difference between the upper and lower plates. This includes rotating the inner gear ring, outer gear ring, and upper plate clockwise, and the lower plate counterclockwise. By adjusting the speed difference between the outer gear ring, inner gear ring, and lower plate, the relative speed difference between the inner and outer edge apexes of the lower plate can be controlled, thereby controlling the inner and outer concavity / convexity.

[0007] The linear velocity at the outer edge vertex of the lower plate is (W) 下 *R 下内 )+(W 修 *R 修 )

[0008] The linear velocity of the inner edge vertex of the lower plate is: (W) 下 *R 下外 )-(W 修 *R 修 )

[0009] The dressing wheel speed W 修 ={(W 外 *N 外 )-(W 内 *N 内 )} / (N 外 -N 内 )-{(W 外 *N 外 )+(W 内 *N 内 )} / (N 外 +N 内 )

[0010] The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment.

[0011] And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the outer edge apex of the lower plate is adjusted by adjusting the rotational speed.

[0012] Optionally, the thickness difference between the inner and outer edges of the polishing cloth can be adjusted by changing the rotational speed difference between the upper and lower plates. This includes rotating the inner gear ring, outer gear ring, and upper plate clockwise, and the lower plate counterclockwise. By adjusting the speed difference between the outer gear ring, inner gear ring, and lower plate, the relative speed difference between the inner and outer edge apexes of the upper plate can be controlled, thereby controlling the inner and outer concavity / convexity.

[0013] The linear velocity at the outer edge vertex of the upper plate is (W) 上 *R 上外 )-(W 修 *R修 )

[0014] The linear velocity at the inner edge vertex of the upper plate is: (W) 上 *R 上内 )+(W 修 *R 修 )

[0015] The dressing wheel speed W 修 ={(W 外 *N 外 )-(W 内 *N 内 )} / (N 外 -N 内 )-{(W 外 *N 外 )+(W 内 *N 内 )} / (N 外 +N 内 )

[0016] The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment.

[0017] And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the inner and outer edge apexes of the upper plate is adjusted by adjusting the rotational speed.

[0018] The above technical solution adjusts the different removal amounts of the polishing pad on the inner and outer surfaces of the polishing cloth by adjusting the rotation speeds of the outer gear ring, inner gear ring, lower plate, and upper plate. The thickness difference of the polishing cloth is used to correct the thickness difference of the polishing plates. By adjusting the polishing linear velocity at the outer edge point to be greater or less than that at the inner edge point, the polishing speed at the outer edge is made greater or less than that at the inner edge. After a period of continuous correction, the thickness of the polishing cloth can be made to exhibit a state of thinner outer and thicker inner, or vice versa, thus offsetting the inconsistency of the polishing plate gap and improving the thickness uniformity of the silicon wafer. Attached Figure Description

[0019] Appendix Figure 1 The diagram shows the implementation steps of the adjustment method for the double-sided polishing machine according to a specific embodiment of the present invention.

[0020] Appendix Figure 2A The diagram shown is a structural schematic of a double-sided polishing machine used in a specific embodiment of the present invention. Figure 2B The image shown is a top view of the lower body.

[0021] Appendix Figure 3 The diagram shown is a schematic representation of the distance measured by the adjustment method of the double-sided polishing machine table according to a specific embodiment of the present invention.

[0022] Appendix Figure 4 The image shown is a top view of the lower plate where the grinding wheel is placed in the adjustment method of the double-sided polishing machine according to a specific embodiment of the present invention. Detailed Implementation

[0023] The specific implementation method of the adjustment method of the double-sided polishing machine provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Appendix Figure 1 The diagram illustrates the implementation steps of the adjustment method for the double-sided polishing machine according to a specific embodiment of the present invention. (See attached diagram.) Figure 1 As shown, this method includes the following steps: Step S10, providing a double-sided polishing machine, the double-sided polishing machine including an upper plate and a lower plate, with an inner gear ring and an outer gear ring disposed between the upper plate and the lower plate, and polishing cloth covering the opposite surfaces of the upper plate and the lower plate; Step S11, measuring the inner gap distance and the outer gap distance between the upper plate and the lower plate to obtain the gap difference value; Step S12, placing a set of grinding wheels between the upper plate and the lower plate; Step S13, simultaneously rotating the upper plate and the lower plate, so that the grinding wheels thin the polishing cloth by rotating to reduce the gap difference value. This step adjusts the linear velocity of the inner and outer edge apexes of the upper plate and the lower plate by adjusting the rotation speed of the outer gear ring, the inner gear ring, the lower plate, and the upper plate. A larger linear velocity corresponds to a greater polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth.

[0025] Referring to step S10, a double-sided polishing machine is provided. (Attached) Figure 2A The diagram shown is a structural schematic of the double-sided polishing machine used in this specific embodiment. Figure 2B The image shown is a top view of the lower plate. The double-sided polishing machine 10 includes an upper plate 11 and a lower plate 12. An internal gear ring 13 and an external gear ring 14 are disposed between the upper plate 11 and the lower plate 12. The opposing surfaces of the upper plate 11 and the lower plate 12 are covered with polishing cloth. (See attached image.) Figure 2A and 2B The diagram shows a polishing machine with a silicon wafer in the polishing state. A carrier 15 is attached between the upper plate 11 and the lower plate 12, and a silicon wafer 16 is loaded on the carrier.

[0026] Referring to step S11, measure the inner and outer clearance distances between the upper plate 11 and the lower plate 12 to obtain the clearance difference. (See attached image) Figure 3The diagram shows the distances measured in this step. The inner clearance distance between the upper plate 11 and the lower plate 12 is d. 内 The outer gap distance is d 外 The gap difference between the two is Δd = d 外 -d 内 Experiments show that this difference affects the morphology of the final polished silicon wafer 16. When Δd < 0, a concave silicon wafer 16 is obtained; conversely, when Δd > 0, a convex silicon wafer 16 is obtained. When Δd = 0, a flat silicon wafer 16 with an ideal morphology is obtained. See the appendix for details. Figure 3 The situation is shown below.

[0027] Referring to step S12, place a set of 20 grinding wheels between the upper platen 11 and the lower platen 12. Figure 4 The image shows a top view of the lower plate on which the grinding wheel is placed. In this embodiment, the grinding wheel 20 includes a circular grinding disc 21. In other embodiments, the grinding wheel may also include three grinding discs arranged in a triangle, mounted on a carrier in the same manner as silicon wafers. The grinding disc 21 is made of diamond. The grinding disc can reduce the thickness of the polishing cloth on the surfaces of the upper and lower plates through grinding.

[0028] Referring to step S13, simultaneously rotate the upper plate 11 and the lower plate 12, causing the grinding wheel 20 to thin the polishing cloth through rotation, thereby reducing the gap difference. This step adjusts the linear velocity of the inner and outer edge apexes of the upper plate 11 and lower plate 12 by adjusting the rotational speeds of the outer gear ring 14, inner gear ring 13, lower plate 12, and upper plate 11. A higher linear velocity corresponds to a greater thinning rate of the polishing cloth, thus adjusting the difference in thickness between the inner and outer edges of the polishing cloth. (Appendix) Figure 4 The diagram shows the lower plate 12, with its inner edge vertex designated A and outer edge vertex designated B. By adjusting the speed difference between the outer gear ring 14, the inner gear ring 13, and the lower plate 12, the relative speed difference between the inner and outer edge vertexes of the lower plate can be controlled, thereby controlling the inner and outer concave / convex shapes. In one specific implementation, the inner gear ring, outer gear ring, and upper plate can all rotate clockwise, while the lower plate rotates counter-clockwise.

[0029] The linear velocity at the outer edge vertex of the lower plate is (W) 下 *R 下内 )+(W 修 *R 修 )

[0030] The linear velocity of the inner edge vertex of the lower plate is: (W) 下 *R 下外 )-(W 修 *R 修 )

[0031] The dressing wheel speed W 修 ={(W 外 *N外 )-(W 内 *N 内 )} / (N 外 -N 内 )-{(W 外 *N 外 )+(W 内 *N 内 )} / (N 外 +N 内 )

[0032] The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment.

[0033] And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the outer edge apex of the lower plate is adjusted by adjusting the rotational speed.

[0034] For the upper plate, the relative speed difference between the outer and inner gear rings and the lower plate can be adjusted to control the inner and outer concave / convex surfaces, thereby controlling the speed difference between the inner and outer edges.

[0035] The linear velocity at the outer edge vertex of the upper plate is (W) 上 *R 上外 )-(W 修 *R 修 )

[0036] The linear velocity at the inner edge vertex of the upper plate is: (W) 上 *R 上内 )+(W 修 *R 修 )

[0037] The dressing wheel speed W 修 ={(W 外 *N 外 )-(W 内 *N 内 )} / (N 外 -N 内 )-{(W 外 *N 外 )+(W内 *N 内 )} / (N 外 +N 内 )

[0038] The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment.

[0039] And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the inner and outer edge apexes of the upper plate is adjusted by adjusting the rotational speed.

[0040] In another specific implementation, the internal gear ring, the external gear ring, and the upper plate can each be set to rotate clockwise or counterclockwise independently, and the linear speed difference can be adjusted according to the above idea.

[0041] While implementing the above adjustment methods, the degree of concavity and convexity of the upper and lower plates can also be adjusted by adjusting the water cooling temperature of the upper and lower plates. Generally speaking, the lower the cooling water temperature, the greater the curvature of the corresponding polishing plate; and the amount of cloth removed can be adjusted by adjusting the mesh size of the polishing disc.

[0042] The above adjustment method regulates the different removal amounts of the abrasive disc on the inner and outer surfaces of the polishing cloth by adjusting the rotation speeds of the outer gear ring, inner gear ring, lower disc, and upper disc. The thickness difference of the polishing disc is corrected by the thickness difference of the polishing cloth. For example, if the d of the polishing disc... 外 -d 内 When Δd > 0, applying a polishing cloth of uniform thickness will result in a convex silicon wafer 16. This can be achieved by adjusting the polishing linear speed at the outer point B to be less than that at the inner point A, thus reducing the polishing speed of the outer edge compared to the inner edge. After a period of adjustment, the thickness of the polishing cloth can be made thicker on the outside and thinner on the inside, offsetting the unevenness of the polishing disc gap and improving the thickness uniformity of the silicon wafer. Conversely, for the case where Δd < 0, this can also be corrected by adjusting the polishing linear speed at point B to be greater than that at point A.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for adjusting a double-sided polishing machine, characterized in that, Includes the following steps: A double-sided polishing machine table is provided, the double-sided polishing machine table includes an upper plate and a lower plate, an internal gear ring and an external gear ring are provided between the upper plate and the lower plate, and the opposing surfaces of the upper plate and the lower plate are covered with polishing cloth; Measure the inner and outer clearance distances between the upper and lower plates to obtain the clearance difference. Place a set of grinding wheels between the upper and lower plates; Simultaneously rotate the upper and lower plates to make the grinding wheel thin the polishing cloth by rotating, thereby reducing the gap difference. This step adjusts the linear speed of the inner and outer edge apexes of the upper and lower plates by adjusting the rotation speed of the outer gear ring, inner gear ring, lower plate, and upper plate. The greater the linear speed, the greater the polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth. The difference in thickness between the inner and outer surfaces of the polishing cloth is adjusted by changing the rotational speed difference between the upper and lower discs, including: Rotate the internal gear ring, external gear ring, and upper plate clockwise, and the lower plate counterclockwise. By adjusting the speed difference between the external gear ring, the internal gear ring, and the lower plate, the relative speed difference between the inner and outer edge vertices of the lower plate can be controlled, thereby controlling the inner and outer concave / convex surfaces. The linear velocity at the outer edge vertex of the lower plate is (W) 下 *R 下内 ) + (W 修 *R 修 ) The linear velocity of the inner edge vertex of the lower plate is: (W) 下 *R 下外 ) - (W 修 *R 修 ) The dressing wheel speed W 修 ={(W 外 *N 外 ) - (W 内 *N 内 )} / (N 外 - N 内 ) - {(W 外 *N 外 ) + (W 内 *N 内 )} / (N 外 + N 内 ) The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment. And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the outer edge apex of the lower plate is adjusted by adjusting the rotational speed.

2. The method according to claim 1, characterized in that, The grinding wheel comprises three grinding discs arranged in a triangular pattern.

3. The method according to claim 2, characterized in that, The grinding disc is made of diamond.

4. A method for adjusting a double-sided polishing machine, characterized in that, Includes the following steps: A double-sided polishing machine table is provided, the double-sided polishing machine table includes an upper plate and a lower plate, an internal gear ring and an external gear ring are provided between the upper plate and the lower plate, and the opposing surfaces of the upper plate and the lower plate are covered with polishing cloth; Measure the inner and outer clearance distances between the upper and lower plates to obtain the clearance difference. Place a set of grinding wheels between the upper and lower plates; Simultaneously rotate the upper and lower plates to make the grinding wheel thin the polishing cloth by rotating, thereby reducing the gap difference. This step adjusts the linear speed of the inner and outer edge apexes of the upper and lower plates by adjusting the rotation speed of the outer gear ring, inner gear ring, lower plate, and upper plate. The greater the linear speed, the greater the polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth. The difference in thickness between the inner and outer surfaces of the polishing cloth is adjusted by changing the rotational speed difference between the upper and lower discs, including: Rotate the internal gear ring, external gear ring, and upper plate clockwise, and the lower plate counterclockwise. By adjusting the speed difference between the external gear ring, the internal gear ring, and the lower plate, the relative speed difference between the inner and outer edge vertices of the upper plate can be controlled, thereby controlling the inner and outer concave / convex surfaces. The linear velocity at the outer edge vertex of the upper plate is (W) 上 *R 上外 ) - (W 修 *R 修 ) The linear velocity at the inner edge vertex of the upper plate is: (W) 上 *R 上内 ) +(W 修 *R 修 ) The dressing wheel speed W 修 ={(W 外 *N 外 ) - (W 内 *N 内 )} / (N 外 - N 内 ) - {(W 外 *N 外 ) + (W 内 *N 内 )} / (N 外 + N 内 ) The above R 上内 R 上外 R 下内 R 下外 and R 修 These are the inner diameter of the upper plate, the outer diameter of the upper plate, the inner diameter of the lower plate, the outer diameter of the lower plate, and the inner diameter of the correction path; N 外 N 内 and N 修 These are the number of teeth on the external gear ring, the number of teeth on the internal gear ring, and the number of teeth on the dressing wheel; these are the fixed values ​​for the equipment. And W 外 W 内 W 下 and W 上 These are the rotational speeds of the external gear ring, internal gear ring, lower plate, and upper plate, respectively. These are adjustable variables, and the linear velocity of the inner and outer edge apexes of the upper plate is adjusted by adjusting the rotational speed.

5. The method according to claim 4, characterized in that, The grinding wheel comprises three grinding discs arranged in a triangular pattern.

6. The method according to claim 5, characterized in that, The grinding disc is made of diamond.

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