Wafer polishing device

Abstract

A wafer polishing device belongs to the technical field of semiconductor device manufacturing device, comprising: horizontal guide rail, wherein the bottom of the section is vertically provided with a main shaft, and the horizontal guide rail is rotationally arranged around the main shaft; a cylinder, the top surface of which is circumferentially arrayed with a plurality of chuck for mounting wafers, the chuck is rotationally arranged around the axis, and the rotational axis is parallel to the main shaft, the bottom surface of the cylinder is provided with a connecting block connected with the horizontal guide rail, and the cylinder is movably arranged along the length direction of the horizontal guide rail; counterweight assembly, arranged on the horizontal guide rail, the counterweight assembly and the connecting block are respectively located at both ends of the horizontal guide rail, and the counterweight assembly is movably arranged along the length direction of the horizontal guide rail; polishing disc, coaxially rotating with the main shaft, arranged above the cylinder, and movably arranged in the vertical direction, the projection of the polishing disc on the horizontal plane covers all the chucks. The scheme can effectively improve the polishing precision of the wafer and the flatness of the wafer surface.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor device manufacturing device, and particularly relates to a wafer polishing device. BACKGROUND

[0002] The wafer is a basic material for manufacturing semiconductor chips. Before the wafer is precisely cut, the wafer needs to be thinned, that is, the single face or double face of the wafer is polished to control the thickness of the wafer within a certain range. In order to ensure the flatness of the wafer surface and prevent local concave or convex defects in the middle or around the wafer surface, the existing polishing device usually polishes only one wafer at a time. Because the smaller the polishing disc is, the easier it is to control the flatness of the polishing disc, thereby ensuring the flatness of the wafer surface. However, this polishing method is low in efficiency. SUMMARY

[0003] To solve the problems in the prior art, the present application provides a wafer polishing device which can effectively improve the polishing precision of the wafer and the flatness of the wafer surface.

[0004] In order to achieve the purpose of the present application, the following scheme is adopted:

[0005] A wafer polishing device comprises:

[0006] A horizontal guide rail, wherein the bottom of the horizontal guide rail is vertically provided with a main shaft, and the horizontal guide rail is rotationally arranged around the main shaft;

[0007] A cylinder, wherein the top surface of the cylinder is circumferentially provided with a plurality of suction cups for mounting wafers, the suction cups are rotationally arranged around an axis, and the axis of rotation is parallel to the main shaft, the bottom surface of the cylinder is provided with a connecting block connected to the horizontal guide rail, and the cylinder is movably arranged along the length direction of the horizontal guide rail;

[0008] A counterweight assembly is arranged on the horizontal guide rail, and the counterweight assembly and the connecting block are respectively located at both ends of the horizontal guide rail, and the counterweight assembly is movably arranged along the length direction of the horizontal guide rail;

[0009] A polishing disc is coaxially rotationally arranged above the cylinder and movably arranged in the vertical direction, and the projection of the polishing disc on the horizontal plane covers all the suction cups.

[0010] The wafer polishing device has the following advantages:

[0011] 1. The cylinder and the polishing disc are eccentrically arranged during polishing, so that each wafer contacts the polishing disc at different radii, thereby avoiding local premature wear of the polishing disc caused by long-term use, effectively avoiding local concave and convex defects of the wafer, and ensuring the flatness of the wafer surface.

[0012] 2. The polishing process utilizes the simultaneously rotating polishing disc, horizontal guide rail and suction disc to set different rotating directions, which forms multi-directional polishing treatment for the wafer, and helps to improve the polishing efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0013] The drawings described herein are only for the purpose of illustrating selected embodiments and are not all possible implementations thereof, and are not intended to limit the scope of the present application.

[0014] Figure 1 The overall structure of the present application is shown in the schematic diagram.

[0015] Figure 2 The preferred structure of the horizontal guide rail is shown in the schematic diagram.

[0016] Figure 3 The preferred structure of the cylinder is shown in the schematic diagram.

[0017] Figure 4 The structure of the cylinder and horizontal guide rail when the slider coincides with the light rod is shown in the sectional view.

[0018] Figure 5 The preferred structure of the cylinder is shown in the schematic diagram. Figure 4 The partial enlarged view at A in the figure.

[0019] Figure 6 The structure of the cylinder and horizontal guide rail when the slider is connected to the screw rod is shown in the sectional view.

[0020] Marked in the figure: horizontal guide rail-1, main shaft-11, limit screw-12, cylinder-2, suction disc-21, gear-211, connecting block-22, driving motor-23, toothed disc-231, elastic member-24, counterweight assembly-3, intermediate block-31, extension rod-32, counterweight block-33, polishing disc-4, screw rod-5, adjusting motor-51, light rod-52, slider-6. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the drawings, but the described embodiments of the present application are only part of the embodiments, not all the embodiments.

[0022] As shown in Figures 1 to 4 and Figure 6 , a wafer polishing device comprises a horizontal guide rail 1, a cylinder 2, a counterweight assembly 3 and a polishing disc 4.

[0023] Specifically, as shown in Figure 2 , a main shaft 11 is vertically arranged at the bottom of the middle section of the horizontal guide rail 1, and the horizontal guide rail 1 is arranged to rotate around the main shaft 11.

[0024] Specifically, in combination with Figures 2 to 4As shown, the top surface of the cylinder 2 is provided with a plurality of chuck 21 for mounting the wafer in circumferential array, the chuck 21 is rotationally arranged around its own axis, and the rotational axis is parallel to the main shaft 11, the chuck 21 is fixed to the wafer by negative pressure adsorption, the middle of the bottom surface of the cylinder 2 is provided with a connecting block 22 connected with the horizontal guide rail 1, the cylinder 2 is movably arranged along the length direction of the horizontal guide rail 1.

[0025] Specifically, as shown in the figure, Figure 2 The counterweight assembly 3 is arranged on the horizontal guide rail 1, the counterweight assembly 3 and the connecting block 22 are respectively located at both ends of the horizontal guide rail 1, the counterweight assembly 3 is movably arranged along the length direction of the horizontal guide rail 1, used to match the moving amount of the cylinder 2, and then ensure that both ends of the horizontal guide rail 1 keep balance relative to the main shaft 11.

[0026] Specifically, as shown in the figure, Figure 1 The polishing disc 4 is coaxially rotationally arranged above the cylinder 2 and movably arranged along the vertical direction, the projection of the polishing disc 4 on the horizontal plane covers all the chucks 21, and the polishing disc 4 and the horizontal guide rail 1 are respectively driven by a single motor.

[0027] The wafer polishing device is used to polish the wafer in the following way:

[0028] Firstly, adjust the position of the cylinder 2 on the horizontal guide rail 1, so that the cylinder 2 is eccentric to the main shaft 11, and adjust the position of the counterweight assembly 3 on the horizontal guide rail 1 to balance the stress at both ends of the horizontal guide rail 1, the adjustment principle is as follows: when the cylinder 2 is farther away from the main shaft 11, the counterweight assembly 3 is also adjusted to a position farther away from the main shaft 11. As a preferred solution, the weight of the cylinder 2 plus the wafer is equal to the weight of the counterweight assembly 3, so that the distance moved by the cylinder 2 and the counterweight assembly 3 relative to the main shaft 11 is the same during adjustment, thereby simplifying the adjustment process.

[0029] Secondly, adsorb the wafer on the top surface of the chuck 21, and use the chuck 21 to adsorb and fix the wafer, specifically, a vacuum pump or an air pump can be arranged inside the cylinder 2, and the vacuum pump or the air pump is connected with the chuck 21, so that the top surface of the chuck 21 generates suction force.

[0030] Thirdly, start the polishing disc 4 and the horizontal guide rail 1, so that both of them rotate around the main shaft 11, and the rotating directions are opposite, at the same time, make the chuck 21 rotate around the axis, and the rotating direction can be the same as or opposite to that of the polishing disc 4; make the polishing disc 4 slowly descend, so that the polishing disc 4 polishes the surface of the wafer during the descending process, and the descending height of the polishing disc 4 is controlled to control the thickness size of the thinning.

[0031] The cylinder 2 and the polishing disc 4 are eccentrically arranged, so that each wafer contacts the polishing disc 4 at different radii, avoiding local premature wear of the polishing disc 4 caused by long-term use, effectively avoiding the defects of local concave and convex of the wafer, and thus ensuring the flatness of the wafer surface.

[0032] Preferably, as shown in Figure 3 、 Figure 4 , the cylinder 2 is internally provided with a driving motor 23 for rotating the suction cups 21, and a gear disc 231 is coaxially arranged on the rotating shaft of the driving motor 23. The lower end of each suction cup 21 is coaxially provided with a gear wheel 211, and the gear wheel 211 is engaged with the gear disc 231. The driving motor 23 drives the gear disc 231 to rotate, thereby driving all the suction cups 21 to rotate in the same direction.

[0033] As a preferred structure, the cylinder 2 includes a barrel body and a barrel cover. The connecting block 22 is arranged on the outer side of the bottom of the barrel body, the driving motor 23 is arranged on the inner side of the bottom of the barrel body, the gear disc 231 is located above the driving motor 23, and the suction cups 21 are all rotatably installed on the barrel cover. The gear wheels 211 are located at the bottom of the barrel cover.

[0034] Preferably, during the polishing process, the counterweight assembly 3 and the cylinder 2 are arranged to move on the horizontal guide rail 1, so that the contact position of the wafer and the polishing disc 4 can be adjusted at any time. The contact position changes along the radial direction of the polishing disc 4, so that the same wafer contacts the polishing disc 4 at different radii, thereby further preventing the problem of local convexity or concavity of the wafer surface caused by polishing the wafer at a fixed radius position of the polishing disc 4. Specifically, telescopic devices can be arranged at both ends of the horizontal guide rail 1 to drive the connecting block 22 and the counterweight assembly 3, thereby meeting the requirement of adjusting the position of the counterweight assembly 3 and the cylinder 2 on the horizontal guide rail 1 at any time.

[0035] Preferably, the total weight of the cylinder 2 and the weight of the installed wafer is equal to the total weight of the counterweight assembly 3. As shown in Figure 2 、 Figure 4 and Figure 6 , a parallel lead screw 5 is arranged on the horizontal guide rail 1. The lead screw 5 has opposite screw threads at both ends. The lead screw 5 passes through the connecting block 22 and the counterweight assembly 3 at both ends, respectively. The front end of the horizontal guide rail 1 is provided with an adjusting motor 51 for driving the lead screw 5 to rotate. When the lead screw 5 rotates, the distance between the cylinder 2 and the counterweight assembly 3 and the main shaft 11 can be adjusted at the same time during the polishing process. Specifically, the power of the adjusting motor 51, the driving motor 23 arranged inside the cylinder 2, and the vacuum pump are all provided through the conductive slip ring from the hollow structure inside the main shaft 11.

[0036] Preferably, as shown in Figures 3 to 6As shown, a sliding block 6 is slidably arranged on the horizontal guide rail 1, the top of the sliding block 6 is slidably connected with the bottom of the cylinder 2, the sliding block 6 is located between the connecting block 22 and the rear end of the horizontal guide rail 1, the rear end of the lead screw 5 passes through the sliding block 6, here the same reference is used to express the front and rear directions of the horizontal guide rail 1 and the direction of the lead screw 5, and the rear end of the lead screw 5 corresponds to the rear end of the horizontal guide rail 1. The two ends of the lead screw 5 described above pass through the connecting block 22 and the counterweight assembly 3 respectively, and the rear end of the lead screw 5 passes through the sliding block 6, which means that the lead screw 5 passes through each component in a threaded connection manner, and the elastic member 24 in a compressed state is arranged between the sliding block 6 and the connecting block 22. This structure not only increases the connecting structure between the cylinder 2 and the horizontal guide rail 1, but also helps to improve the stability of the cylinder 2 installation structure, and the elastic member 24 in a compressed state generates opposite pre-tightening force on the sliding block 6 and the connecting block 22, which helps to improve the fit between the sliding block 6, the connecting block 22 and the lead screw 5, effectively eliminates the thread gap, and effectively avoids the shaking of the cylinder 2 relative to the main shaft 11 during the polishing process, reduces the vibration of the cylinder 2 during the rotation process, thereby improving the polishing precision of the wafer, and further ensuring the flatness of the wafer surface.

[0037] Preferably, as shown in Figure 2 , Figure 3 , the top surface of the horizontal guide rail 1 is provided with a dovetail groove along the length direction, the connecting block 22 and the sliding block 6 are both dovetail block structures and are slidably arranged in the dovetail groove, and the counterweight assembly 3 includes an intermediate block 31 slidably arranged in the dovetail groove.

[0038] Further preferably, as shown in Figure 2 , strip-shaped holes communicating with the dovetail groove are arranged on both sides of the front end of the horizontal guide rail 1, and the intermediate block 31 is provided with an extension rod 32 on both sides, the extension rod 32 is used for installing a counterweight block 33, and the counterweight block 33 is detachably installed on the extension rod 32, so as to adjust the number and meet the needs of different counterweights. The distance between the sliding block 6 and the connecting block 22 is adjustable, which is used to adjust the elastic force of the elastic member 24.

[0039] Preferably, as shown in Figures 4 to 6As shown, the rear end of the screw rod 5 has a light rod 52, the outer diameter of the light rod is smaller than the small diameter of the screw thread of the screw rod 5, and the length of the light rod 52 is greater than or equal to the thickness of the sliding block 6 in the length direction of the screw rod 5, when the sliding block 6 coincides with the light rod 52, the screw thread of the screw rod 5 is separated from the sliding block 6, so that even if the screw rod 5 rotates, the sliding block 6 cannot be moved, so as to adjust the distance between the connecting block 22 and the sliding block 6; the specific adjustment method is as follows: the rotation direction of the screw rod 5 is defined as positive rotation when the sliding block 6 moves to the rear end of the screw rod 5; first, rotate the screw rod 5 to move the sliding block 6 to the rear end of the screw rod 5 until the sliding block 6 is separated from the screw thread of the screw rod 5, at this time the sliding block 6 coincides with the light rod 52, when it is needed to increase the distance between the sliding block 6 and the connecting block 22, so as to reduce the elastic force of the elastic member 24, then the screw rod 5 needs to be rotated in the reverse direction, so that the connecting block 22 moves to the front end of the screw rod 5; on the contrary, if it is needed to reduce the distance between the sliding block 6 and the connecting block 22, so as to increase the elastic force of the elastic member 24, then the screw rod 5 needs to be rotated in the positive direction, so that the connecting block 22 moves to the sliding block 6; after adjustment, the sliding block 6 is pushed to the front end of the screw rod 5 by an external force, and the screw rod 5 is rotated in the reverse direction, so that the sliding block 6 is connected with the screw thread of the screw rod 5 again, and the screw rod 5 will also drive the sliding block 6 and the connecting block 22 to move in the subsequent rotation process, so as to keep the elastic force of the elastic member 24 constant.

[0040] Further preferably, as shown in the drawings, Figure 5 As shown, the rear end of the horizontal guide rail 1 is provided with a limiting screw 12 penetrating along the length direction, which is used to limit the limit position of the rear movement of the sliding block 6, so as to avoid the separation of the sliding block 6 and the screw thread of the screw rod 5, when it is needed to actively separate the sliding block 6, the limiting screw 12 is removed to remove the limiting effect on the sliding block 6, and the screw rod 5 is rotated in the positive direction.

[0041] As preferred, the top of the sliding block 6 and the top of the counterweight assembly 3 are connected with the bottom of the cylinder 2 in sliding mode, the bottom of the cylinder 2 is provided with a strip-shaped groove, and the top of the sliding block 6 and the top of the counterweight assembly 3 are provided with a protrusion connected with the strip-shaped groove, further preferably, the strip-shaped groove is a T-shaped groove structure, and the protrusion is a T-shaped block structure, this structure not only increases the connecting structure between the cylinder 2 and the horizontal guide rail 1, but also helps to improve the stability of the installation structure of the cylinder 2.

[0042] The above only describes the preferred embodiments of the present application, and does not mean the only or limit the present application. Those skilled in the art should understand that various changes or equivalent replacements made to the present application without departing from the scope of the present application, all belong to the protection scope of the present application.

Claims

1. A wafer polishing apparatus characterized by comprising: The application relates to a polishing device for polishing a plurality of wafers, which comprises the following components: a horizontal guide rail (1), wherein the bottom of each section is vertically provided with a main shaft (11), and the horizontal guide rail (1) is rotationally arranged around the main shaft (11); a cylinder (2), wherein the top surface of the cylinder (2) is circumferentially provided with a plurality of chucking discs (21) for mounting wafers, the chucking discs (21) are rotationally arranged around an axis, and the rotation axis is parallel to the main shaft (11), the bottom surface of the cylinder (2) is provided with a connecting block (22) connected with the horizontal guide rail (1), and the cylinder (2) is movably arranged along the length direction of the horizontal guide rail (1); a counterweight assembly (3) arranged on the horizontal guide rail (1), wherein the counterweight assembly (3) is located at the two ends of the horizontal guide rail (1) respectively, and the counterweight assembly (3) is movably arranged along the length direction of the horizontal guide rail (1); a polishing disc (4) coaxially rotationally arranged above the cylinder (2) and movably arranged along the vertical direction, and the projection of the polishing disc (4) on the horizontal plane covers all the chucking discs (21); during the polishing process, the counterweight assembly (3) and the cylinder (2) are movably arranged on the horizontal guide rail (1); the total weight of the cylinder (2) and the wafers mounted on the cylinder (2) is equal to the total weight of the counterweight assembly (3); a parallel screw rod (5) is arranged on the horizontal guide rail (1), the screw rod (5) is provided with threads with opposite rotation directions at the two ends, the two ends of the screw rod (5) pass through the connecting block (22) and the counterweight assembly (3) respectively, and the front end of the horizontal guide rail (1) is provided with an adjusting motor (51) for driving the screw rod (5) to rotate; a sliding block (6) is slidably arranged on the horizontal guide rail (1), the top of the sliding block (6) is slidably connected with the bottom of the cylinder (2), the sliding block (6) is located between the connecting block (22) and the rear end of the horizontal guide rail (1), the rear end of the screw rod (5) passes through the sliding block (6), and the elastic element (24) in the compressed state is arranged between the sliding block (6) and the connecting block (22), and the distance between the sliding block (6) and the connecting block (22) is adjustable; the rear end of the screw rod (5) is provided with a light rod (52), the outer diameter of the light rod is smaller than the small diameter of the thread of the screw rod (5), and the length of the light rod (52) is greater than or equal to the thickness of the sliding block (6) in the length direction of the screw rod (5), when the sliding block (6) is coincident with the light rod (52), the thread of the screw rod (5) is separated from the sliding block (6).

2. The wafer polishing apparatus of claim 1, wherein a driving motor (23) is arranged in the cylinder (2) and is used for driving the chucking discs (21) to rotate, a gear disc (231) is coaxially arranged on the rotating shaft of the driving motor (23), and the lower end of each chucking disc (21) is coaxially provided with a gear (211), and the gear (211) is engaged with the gear disc (231).

3. The wafer polishing apparatus of claim 1, wherein a limiting screw (12) is arranged on the rear end of the horizontal guide rail (1) along the length direction, and is used for limiting the limit position of the rearward movement of the sliding block (6).

4. The wafer polishing apparatus of claim 1, wherein the top of the counterweight assembly (3) is slidably connected with the bottom of the cylinder (2).

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