Adjusting method of double-sided polishing machine table

Abstract

The invention provides an adjusting method of a double-sided polishing machine table. The method comprises the following steps that a double-face polishing machine table is provided, the double-face polishing machine table comprises an upper disc and a lower disc, an inner gear ring and an outer gear ring are arranged between the upper disc and the lower disc, and the opposite surfaces of the upper disc and the lower disc are covered with polishing cloth; measuring an inner gap distance and an outer gap distance between the upper disc and the lower disc to obtain a gap difference value; a group of grinding wheels are arranged between the upper disc and the lower disc; in the step, the vertex linear speed of the inner edge and the outer edge of the upper disc and the vertex linear speed of the outer edge and the vertex linear speed of the lower disc are adjusted by adjusting the rotating speed of the outer gear ring, the rotating speed of the inner gear ring, the rotating speed of the lower disc and the rotating speed of the upper disc, and the higher linear speed corresponds to the higher polishing cloth thinning speed. Therefore, the internal and external thickness difference of the polishing cloth is adjusted. According to the method, different internal and external removal amounts of the polishing disc to the polishing cloth are adjusted by adjusting the rotating speeds of the outer gear ring, the inner gear ring, the lower disc and the upper disc, and the thickness difference of the polishing disc is corrected through the thickness difference of the polishing cloth.

Description

Technical Field

[0001] The invention relates to the field of semiconductor equipment, and in particular to an adjustment method for a double-sided polishing machine. Background Art

[0002] Double-sided polishing machine is a common equipment in semiconductor equipment. The polishing machine includes an upper plate and a lower plate, and a carrier is placed between the upper and lower plates. The upper and lower plates are made of metal discs with cooling water flowing inside. The temperature of the cooling water is adjusted according to the principle of thermal expansion and contraction of metal to control the expansion and contraction of the upper and lower plates. The inner and outer gear rings are placed between the upper and lower plates to provide driving force for the carrier. The carrier is used to carry silicon wafers to ensure that the silicon wafers will not slip out during rotation processing.

[0003] When the machine is running, there are 4 active rotating parts, among which the upper and lower discs rotate relative to each other in clockwise and counterclockwise directions, and the inner and outer gear rings drive the carrier to revolve around the center of the equipment while the carrier rotates on itself. During the rotation, the silicon wafer clamped in the middle is polished. Experiments have found that the thickness of the polishing wafer produced by the polishing machine will show inconsistent thickness in the middle and around, and one of the reasons for this problem is the inconsistency of the gap between the upper and lower polishing discs. Therefore, how to adjust the consistency of the gap between the upper and lower polishing discs, thereby improving the consistency of the thickness of the polishing discs, is a problem that the prior art needs to solve. 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, which 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 disc.

[0005] In order to solve the above problems, the present 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, an inner gear ring and an outer gear ring are arranged between the upper plate and the lower plate, and the relative surfaces of the upper plate and the lower plate are covered with polishing cloth; measuring the inner gap distance and the outer gap distance between the upper plate and the lower plate to obtain the gap difference; placing a group of grinding wheels between the upper plate and the lower plate; rotating the upper plate and the lower plate at the same time so that the grinding wheels thin the polishing cloth by rotation to reduce the gap difference. In this step, the linear speed of the inner and outer edge vertices of the upper and lower plates is adjusted by adjusting the outer gear ring, the inner gear ring, the lower plate, and the rotation speed of the upper plate. The larger the linear speed, the greater the 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 sides of the polishing cloth can be adjusted by adjusting the speed difference between the upper and lower plates, including: rotating the inner gear ring, the outer gear ring and the upper plate clockwise, and rotating the lower plate counterclockwise; adjusting the speed difference between the outer gear ring, the inner gear ring and the lower plate, so that the relative speed difference between the inner and outer edge vertices of the lower plate can be controlled according to the speed, thereby controlling the inner and outer convexities.

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

[0008] The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment.

[0011] And W 外 , W 内 , W 下 , and W 上 They are the rotation speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables, and the linear speed of the vertex of the outer edge of the lower plate can be adjusted by adjusting the rotation speed.

[0012] Optionally, the thickness difference between the inner and outer sides of the polishing cloth can be adjusted by adjusting the speed difference between the upper and lower plates, including: rotating the inner gear ring, the outer gear ring and the upper plate clockwise, and rotating the lower plate counterclockwise; adjusting the speed difference between the outer gear ring, the inner gear ring and the lower plate, so that the relative speed difference between the inner and outer edge vertices of the upper plate can be controlled according to the speed, thereby controlling the inner and outer convexities.

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

[0014] The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment.

[0017] And W 外 , W 内 , W 下 , and W 上 They are the rotational speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables. The linear speed of the vertices of the inner and outer edges of the upper plate can be adjusted by adjusting the rotational speed.

[0018] The above technical solution adjusts the different removal amounts of the polishing cloth inside and outside by the grinding disc by adjusting the rotation speed of the outer gear ring, the inner gear ring, the lower plate, and the upper plate, and corrects the thickness difference of the polishing disc by the thickness difference of the polishing cloth. By adjusting the polishing line speed of the outer edge point to be greater than or less than the inner edge point, the polishing speed of the outer edge is made greater than or less than the inner edge. After a certain period of correction, the thickness of the polishing cloth can be made thin outside and thick inside or thick outside and thin inside, offsetting the inconsistency of the gap between the polishing discs and improving the thickness consistency of the silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Attached Figure 1 Shown is a schematic diagram of the implementation steps of the adjustment method of the double-sided polishing machine described in a specific embodiment of the present invention.

[0020] Attached Figure 2A FIG. 1 is a schematic diagram of the structure of a double-sided polishing machine used in a specific embodiment of the present invention, and FIG. Figure 2B Shown is a top view of the footwall.

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

[0022] Attached Figure 4 Shown is a top view of a lower plate on which a grinding wheel is placed in an adjustment method of a double-sided polishing machine according to a specific embodiment of the present invention. DETAILED DESCRIPTION

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

[0024] Attached Figure 1 FIG. 1 is a schematic diagram of the implementation steps of the adjustment method of the double-sided polishing machine according to a specific embodiment of the present invention. Figure 1 As shown, the method includes the following steps: step S10, providing a double-sided polishing machine, the double-sided polishing machine includes an upper plate and a lower plate, an inner gear ring and an outer gear ring are arranged between the upper plate and the lower plate, and the relative surfaces of the upper plate and the lower plate are covered with polishing cloth; 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; step S12, placing a group of grinding wheels between the upper plate and the lower plate; step S13, rotating the upper plate and the lower plate at the same time, so that the grinding wheels thin the polishing cloth by rotating to reduce the gap difference. In this step, the linear speed of the inner and outer edge vertices of the upper and lower plates is adjusted by adjusting the outer gear ring, the inner gear ring, the lower plate, and the rotation speed of the upper plate. The larger the linear speed, the greater the 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. Figure 2A The structure diagram of the double-sided polishing machine used in this specific embodiment is shown in FIG. Figure 2B The double-sided polishing machine 10 used comprises an upper plate 11 and a lower plate 12, between which an inner gear ring 13 and an outer gear ring 14 are arranged, and the opposite surfaces of the upper plate 11 and the lower plate 12 are covered with polishing cloth. Figure 2A and 2B The figure is a schematic diagram of a polishing machine loading a silicon wafer for polishing, wherein a carrier 15 is placed between an upper plate 11 and a lower plate 12, and a silicon wafer 16 is loaded on the carrier.

[0026] Referring to step S11, the inner gap distance and the outer gap distance between the upper plate 11 and the lower plate 12 are measured to obtain the gap difference. Figure 3The 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 will affect the morphology of the final ground silicon wafer 16. When Δd < 0, a concave silicon wafer 16 will be obtained; conversely, when Δd > 0, a convex silicon wafer 16 will be obtained. When Δd = 0, a flat silicon wafer 16 with an ideal morphology will be obtained. For details, see the attached Figure 3 The situation shown.

[0027] Referring to step S12, a set of grinding wheels 20 is placed between the upper plate 11 and the lower plate 12. Figure 4 The figure shows a top view of the lower plate with the grinding wheel placed thereon. In this embodiment, the grinding wheel 20 includes a grinding disc 21 in the shape of a ring. In other embodiments, the grinding wheel may also include three grinding discs arranged in a triangle, which are mounted on the carrier in the same manner as a silicon wafer. The material of the grinding disc 21 is diamond. The grinding disc can thin the polishing cloth of the upper plate and the lower plate surface by grinding.

[0028] Referring to step S13, the upper plate 11 and the lower plate 12 are rotated at the same time, so that the grinding wheel 20 thins the polishing cloth by rotating to reduce the gap difference. This step adjusts the linear speed of the inner and outer edges of the upper plate 11 and the lower plate 12 by adjusting the rotation speed of the outer gear ring 14, the inner gear ring 13, the lower plate 12, and the upper plate 11. The larger the linear speed, the greater the polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth. Figure 4 The schematic diagram of the lower plate 12 is shown, and the corresponding inner edge vertex of the lower plate is A, and the outer edge vertex is 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 vertices of the lower plate can be controlled according to the speed, thereby controlling the inner and outer concavities. As a specific implementation method, the inner gear ring, the outer gear ring and the upper plate can all rotate clockwise, and the lower plate can rotate counterclockwise.

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

[0030] The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment.

[0033] And W 外 , W 内 , W 下 , and W 上 They are the rotation speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables, and the linear speed of the vertex of the outer edge of the lower plate can be adjusted by adjusting the rotation speed.

[0034] For the upper plate, the speed difference between the outer gear ring, the inner gear ring and the lower plate can be adjusted to control the relative speed difference between the vertices of the inner and outer edges of the upper plate according to the speed, thereby controlling the inner and outer concavities.

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

[0036] The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment.

[0039] And W 外 , W 内 , W 下 , and W 上 They are the rotational speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables. The linear speed of the vertices of the inner and outer edges of the upper plate can be adjusted by adjusting the rotational speed.

[0040] In another specific implementation, the inner gear ring, the outer gear ring and the upper disk may be independently set to rotate clockwise or counterclockwise, and the linear speed difference may be adjusted according to the above idea.

[0041] While implementing the above-mentioned adjustment method, the degree of 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 convex or concave curvature of the corresponding polishing disc; and the amount of polishing cloth removed can be adjusted by adjusting the mesh size of the grinding disc.

[0042] The above adjustment method adjusts the different removal amounts of the grinding disc on the inner and outer sides of the polishing cloth by adjusting the rotation speed of the outer gear ring, inner gear ring, lower plate, and upper plate, and corrects the thickness difference of the polishing disc by the thickness difference of the polishing cloth. 外 -d 内 =Δd>0, if a polishing cloth with consistent thickness is applied, a convex silicon wafer 16 will be obtained. By implementing the above method, the polishing line speed of the outer point B can be adjusted to be lower than that of the inner point A, so that the polishing speed of the outer edge is lower than that of the inner edge. After a period of correction, the thickness of the polishing cloth can be made thick on the outside and thin on the inside, offsetting the situation that the gap between the polishing discs is larger on the outside and smaller on the inside, and improving the thickness consistency of the silicon wafer. Conversely, for the case of Δd<0, correction can also be made by adjusting the polishing line speed of point B to be higher than that of point A.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for adjusting a double-sided polishing machine, characterized in that: The steps include: A double-sided polishing machine is provided, the double-sided polishing machine comprising an upper plate and a lower plate, an inner gear ring and an outer gear ring are arranged between the upper plate and the lower plate, and the opposite surfaces of the upper plate and the lower plate are covered with polishing cloth; Measuring the inner gap distance and the outer gap distance between the upper plate and the lower plate to obtain the gap difference; A set of grinding wheels is placed between the upper and lower discs; The upper and lower plates are rotated at the same time, so that the grinding wheel can thin the polishing cloth by rotating to reduce the gap difference. In this step, the linear speed of the inner and outer edge vertices of the upper and lower plates is adjusted by adjusting the outer gear ring, the inner gear ring, the lower plate, and the rotation speed of the upper and lower plates. The larger the linear speed, the greater the polishing cloth thinning speed, thereby adjusting the inner and outer thickness difference of the polishing cloth.

2. The method according to claim 1, characterized in that By adjusting the speed difference between the upper and lower discs, the thickness difference between the inner and outer sides of the polishing cloth can be adjusted, including: Rotate 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, the inner gear ring and the lower plate, the relative speed difference between the inner and outer edge vertices of the lower plate can be controlled according to the speed, thereby controlling the inner and outer concavities. The linear velocity of the vertex of the lower plate outer edge is (W 下 *R 下内 )+(W 修 *R 修 ) The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment; And W 外 , W 内 , W 下 , and W 上 They are the rotation speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables, and the linear speed of the vertex of the outer edge of the lower plate can be adjusted by adjusting the rotation speed.

3. The method according to claim 1, characterized in that By adjusting the speed difference between the upper and lower discs, the thickness difference between the inner and outer sides of the polishing cloth can be adjusted, including: Rotate 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, the inner gear ring and the lower plate, the relative speed difference between the inner and outer edge vertices of the upper plate can be controlled according to the speed, thereby controlling the inner and outer concavities. The linear velocity of the vertex of the upper plate outer edge is (W 上 *R 上外 )-(W 修 *R 修 ) The linear velocity of the vertex of the inner edge 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 They are the upper plate inner diameter, upper plate outer diameter, lower plate inner diameter, lower plate outer diameter, and correction road inner diameter; N 外 、N 内 , and N 修 They are the number of teeth on the outer gear ring, the number of teeth on the inner gear ring, and the number of teeth on the dressing wheel. The above are fixed values ​​for the equipment. And W 外 , W 内 , W 下 , and W 上 They are the rotational speeds of the outer gear ring, inner gear ring, lower plate, and upper plate respectively. The above are adjustable variables. The linear speed of the vertices of the inner and outer edges of the upper plate can be adjusted by adjusting the rotational speed.

4. The method according to claim 1, characterized in that: The grinding wheel includes three grinding plates arranged in a triangle.

5. The method according to claim 4, characterized in that The material of the grinding disc is diamond.

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