Multi-piece adsorption mechanism for grinding clamp

Abstract

The utility model discloses a multi-wafer adsorption mechanism for a grinding fixture. The multi-wafer adsorption mechanism comprises a large grinding fixture outer bracket, a wafer adsorption mechanism and a pin lifting mechanism, a driving ring is arranged at the bottom of the large grinding clamp outer support and connected to a fixing plate through a plurality of supporting columns, a hollow shaft sleeve is arranged in the center of the fixing plate, and pin lifting mechanisms are arranged on the two sides of the fixing plate. The wafer adsorption mechanism comprises an adsorption surface, an adsorption surface fixing plate, an upper substrate, a lifting rod and a piston rod; a piston rod is arranged in the center of the upper substrate, is connected with the shaft sleeve, and moves up and down in the shaft sleeve to drive the wafer adsorption mechanism to move up and down in the large grinding clamp outer bracket; an adsorption surface fixing plate is arranged below the upper substrate, three adsorption surfaces are fixed at the bottom of the adsorption surface fixing plate, and an arc-shaped groove compatible with the adsorption surfaces is formed in the driving ring. According to the utility model, three 4-inch sheets can be fixed and ground at the same time, so that the production and use efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of precision grinding of semiconductor materials, and relates to a semi-automatic precision grinding mechanism, in particular to a multi-piece adsorption mechanism of a grinding fixture. Background Art

[0002] During the surface treatment of semiconductor wafers and materials, they need to be ground. Grinding is to subtract thickness from them, removing a certain thickness of material to make the wafer and material thinner as a whole and achieve a good TTV surface.

[0003] During the grinding process, the fixture holds the wafer and material for precision machining on the grinder. During the machining, the fixture needs to apply a certain amount of pressure on the surface of the wafer / material to ensure that the wafer / material is processed correctly. The main function of the fixture during the grinding process is to ensure the surface flatness of the wafer / material after processing and to control the downward pressure.

[0004] Taking GaAs device wafers as an example, the wafer back-reduction processing size has gradually upgraded from 4 inches to 6 inches, 8 inches and other large sizes. For example, the large grinding fixture adsorption mechanism of the upgraded grinding machine can fix an 8-inch or 6-inch wafer at a time. Figure 1 The original large grinding fixture has a single wafer adsorption mechanism, and its adsorption surface is designed with three inner and outer zones, which are divided into 4-inch center zone A, 6-inch outer ring zone B and 8-inch outer ring zone C. The three zones can be adsorbed separately through vacuum control: when zone A is vacuumed alone, 4-inch wafers are adsorbed; when zone A+B is vacuumed, 6-inch wafers are adsorbed; when zone A+B+C is vacuumed, 8-inch wafers are adsorbed. This large fixture can adsorb 4-inch, 6-inch or 8-inch wafers at a time. For 4-inch wafers, this fixture has low processing efficiency, poor compatibility, and is not convenient for improving grinding efficiency. Utility Model Content

[0005] Purpose of the utility model: The purpose of the utility model is to solve the above-mentioned problems of 4-inch sheet efficiency and configuration compatibility, and to provide a multi-sheet adsorption mechanism for a large grinding fixture to improve production and use efficiency.

[0006] Technical solution: The utility model is a multi-piece adsorption mechanism for a grinding fixture, comprising a large grinding fixture outer bracket, a wafer adsorption mechanism and a lifting and pinning mechanism; the bottom of the large grinding fixture outer bracket is a driving ring, the driving ring is connected to a fixed plate through a plurality of support columns, a hollow sleeve is provided in the center of the fixed plate, and lifting and pinning mechanisms are provided on both sides of the fixed plate;

[0007] The wafer adsorption mechanism comprises an adsorption surface, an adsorption surface fixing plate, an upper base plate, a lifting rod and a piston rod; a piston rod is arranged at the center of the upper base plate, the piston rod is connected to the shaft sleeve, and the piston rod moves up and down in the shaft sleeve to drive the wafer adsorption mechanism to move up and down in the outer bracket of the large grinding fixture;

[0008] An adsorption surface fixing plate is arranged below the upper substrate, three adsorption surfaces are fixed at the bottom of the adsorption surface fixing plate, and an arc-shaped groove compatible with the adsorption surfaces is arranged on the driving ring.

[0009] Furthermore, the wafer adsorption mechanism also includes a vacuum duct and a guide plate. There are three vacuum ducts, which provide vacuum for three adsorption surfaces respectively and are arranged on one side of the upper substrate; the guide plate is located between the upper substrate and the adsorption surface fixing plate for vacuum conduction and sealing, and the guide plate and the adsorption surface fixing plate are both provided with corresponding vacuum guide holes and vacuum grooves, and the vacuum duct, vacuum guide holes and vacuum grooves form a vacuum channel to the adsorption surface; the front side of the adsorption surface is designed as a central through hole with a plurality of evenly distributed radiation grooves, and the central through hole is annularly grooved outwardly, each annular groove has a guide hole, and each of the guide holes is connected to the vacuum channel through the central through hole.

[0010] Furthermore, a middle barrier is provided between the three adsorption surfaces, and an upper surface of the middle barrier is higher than upper surfaces of the three adsorption surfaces to form a height difference, and the height difference is smaller than the thickness of the glass substrate or sapphire substrate to which the crystal circle is bonded.

[0011] Furthermore, a pressure regulating nut is threadedly connected to the upper portion of the shaft sleeve, and a micrometer is fixed to the lower portion of the shaft sleeve via a bracket.

[0012] Furthermore, the micrometer is located at a symmetrical position of the three vacuum tubes, so that the weight of the micrometer and the three vacuum tubes forms a left-right symmetrical balance.

[0013] Furthermore, lifting rods are provided on both sides of the upper base plate, and corresponding lock buckles are provided on the fixing plate.

[0014] Furthermore, a fixing block and a clamp connecting block are fixed to the upper portion of the piston rod.

[0015] Furthermore, the drive ring is made of wear-resistant metal material, wear-resistant ceramic material or electroplated diamond surface.

[0016] Furthermore, the adsorption surface and the adsorption surface fixing plate are made of wear-resistant and corrosion-resistant metal or ceramic materials.

[0017] Furthermore, the middle partition is made of wear-resistant plastic material.

[0018] Beneficial effects: Compared with the prior art, the utility model has the following advantages: three 4-inch sheets can be fixed and ground at the same time, which solves the grinding efficiency problem of a single large fixture for a 4-inch sheet, and also solves the problem of large-size fixtures being compatible with small-size ones. The upgraded grinder can not only meet the upgraded use of large-size 6-8-inch sheets, but also meet the efficient grinding of the original 4-inch samples, and perfectly connect with the subsequent 4-inch polishing. This not only improves production and use efficiency, but also reduces waste and losses caused by equipment incompatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the original single-piece adsorption mechanism of the large grinding fixture.

[0020] Figure 2 It is a schematic diagram of the overall structure of the utility model.

[0021] Figure 3 It is a schematic structural diagram of the outer bracket of the large grinding fixture of the utility model.

[0022] Figure 4 It is a side structural schematic diagram of the wafer adsorption mechanism of the present utility model.

[0023] Figure 5 It is a schematic diagram of the bottom structure of the wafer adsorption mechanism of the present utility model.

[0024] Figure 6 This is a schematic diagram of the structure of the adsorption surface fixing plate of the utility model.

[0025] Figure 7 It is a structural schematic diagram of the guide plate of the utility model.

[0026] Figure 8 It is a structural schematic diagram of the drive ring of the utility model. DETAILED DESCRIPTION

[0027] The technical solution of the utility model is further described below in conjunction with the accompanying drawings.

[0028] Please combine Figure 2-5As shown, a multi-piece adsorption mechanism for a grinding fixture involved in this embodiment includes an outer bracket 1 for a large grinding fixture and a wafer adsorption mechanism 2. The wafer adsorption mechanism 2 is connected to the sleeve 105 through a piston rod 207, and forms a multi-piece adsorption mechanism for the grinding fixture as a whole with the outer bracket 1 for the large grinding fixture. The outer bracket 1 for the large grinding fixture provides support for the multi-piece adsorption mechanism for the entire grinding fixture, and its bottom is a driving ring 101 with multiple support columns 102, and the multiple support columns 102 are connected to the fixed plate 103 by screws. The hollow sleeve 105 is fixed to the center of the fixed plate 103, and the upper part of the sleeve 105 is threadedly connected to a pressure regulating nut 104, and the lower part is fixed with a micrometer 107 through a bracket 106, so that the grinding thickness is more accurate. Two lifting and pinning mechanisms 109 are respectively fixed on both sides of the fixed plate 103, which are used to lift the fixture and drive the fixture to rotate as a whole during the grinding process.

[0029] The wafer adsorption mechanism 2 mainly provides adsorption and pressure for the wafer, and includes an adsorption surface 201, an adsorption surface fixing plate 202, a guide plate 203, an upper base plate 204, a lifting rod 205, a vacuum duct 206 and a piston rod 207. A piston rod 207 is fixed at the center of the upper base plate 204 of the wafer adsorption mechanism 2. The piston rod 207 moves up and down in the shaft sleeve 105, thereby driving the wafer adsorption mechanism 2 to move up and down in the outer bracket 1 of the large grinding fixture. A fixing block 209 and a fixture connecting block 210 are fixed to the upper part of the piston rod 207. Two lifting rods 205 are arranged on both sides of the upper base plate 204, and a lock buckle 108 is arranged at the corresponding position of the fixing plate 103, which is used to lock the lifting rod 205 to prevent the wafer adsorption surface mechanism 2 from falling as a whole and causing damage to the wafer.

[0030] A guide plate 203 and an adsorption surface fixing plate 202 are arranged below the upper base plate 204. Three adsorption surfaces 201 are fixed to the bottom of the adsorption surface fixing plate 202. There is a middle barrier 212 between the three adsorption surfaces 201. Three vacuum ducts 206 are arranged on one side of the upper base plate 204. The positions thereof form a left-right symmetrical balance in weight with the micrometer 107. The three vacuum ducts 206 provide vacuum for the three adsorption surfaces 201 respectively.

[0031] The front of the adsorption surface 201 is designed as a central through hole with four or more evenly distributed radiation grooves, and the center is annularly grooved outward, each annular groove has a guide hole; these guide holes are connected to the central through hole on the back of the adsorption surface 201, and then connected to the corresponding vacuum channel. The material of the adsorption surface 201 can be a wear-resistant and corrosion-resistant metal material, such as stainless steel, etc., or a wear-resistant and corrosion-resistant ceramic material. The adsorption surface fixing plate 202 is made of metal or ceramic material, and it can also be designed and processed as an integrated whole with the adsorption surface 201, such as being processed as a stainless steel material or a ceramic material as a whole. The middle partition 212 is fixed to the center of the adsorption surface fixing plate 202 by magnetism or screws, and acts as a partition between the three adsorption surfaces 201 to prevent mutual collision and damage caused by displacement due to loose adsorption of the wafer during the grinding process. The middle partition 212 is made of wear-resistant plastic material, such as PVC, nylon, POM, etc. The upper surface of the middle barrier 212 is higher than the upper surfaces (adsorption surfaces) of the three adsorption surfaces 201 to form a height difference, and the height difference H should be smaller than the thickness of the glass substrate or sapphire substrate to which the wafer is bonded.

[0032] Please combine Figure 6 , Figure 7 The guide plate 203 is located between the upper substrate 204 and the adsorption surface fixing plate 202, and mainly plays the role of vacuum conduction and sealing. The guide plate 203 and the adsorption surface fixing plate 202 are both provided with corresponding vacuum guide holes and vacuum grooves, vacuum conduits, vacuum guide holes and vacuum grooves to form a vacuum channel to the adsorption surface 201. In a specific embodiment, the back of the adsorption surface fixing plate 202 has a vacuum guide hole 301 and a vacuum guide groove 302, and the vacuum guide hole 301 is connected to the central through hole of the adsorption surface 201. The upper part of the guide plate 203 has a vacuum guide groove 304 and a vacuum guide hole 303, and the vacuum guide groove 304 is connected to the vacuum guide groove 302 and the vacuum guide hole 301 on the lower adsorption surface fixing plate 202 through the vacuum guide hole 303. The vacuum guide groove 304 is connected to the vacuum conduit 206 on the upper substrate 204. These guide grooves, guide holes and conduits together form a vacuum channel to the adsorption surface 201.

[0033] Please combine Figure 8 In order to not expand the outer diameter of the fixture and to accommodate three four-inch adsorption surfaces 201, the fixture drive ring 101 is cut and removed at the corresponding positions. The arc areas a1, a2, a3, and a4 in the figure are the cut areas. At the same time, the thickness of the drive ring 101 is appropriately increased to increase its rigidity. In order to adapt to a variety of wafer materials, the drive ring 101 is made of wear-resistant metal or wear-resistant ceramic material, or electroplated diamond surface.

[0034] After experimental comparison and testing, the multi-piece adsorption mechanism of the grinding fixture of the utility model can process 3 4-inch wafers at a time, with controllable pressure and convenient operation, and is suitable for various thicknesses and various wafer materials. The TTV within the processed wafer is <= 4 microns, and the TTV between wafers is <= 5 microns. It greatly improves the grinding efficiency and improves and enhances the indicators of the processed wafers.

Claims

1. A multi-piece adsorption mechanism for a grinding fixture, characterized in that: It includes a grinding jig outer bracket, a wafer adsorption mechanism and a lifting and pinning mechanism; the bottom of the grinding jig outer bracket is a driving ring, the driving ring is connected to a fixed plate through a plurality of support columns, a hollow sleeve is arranged at the center of the fixed plate, and lifting and pinning mechanisms are arranged on both sides of the fixed plate; The wafer adsorption mechanism comprises an adsorption surface, an adsorption surface fixing plate, an upper base plate, a lifting rod and a piston rod; a piston rod is arranged at the center of the upper base plate, the piston rod is connected to the shaft sleeve, and the piston rod moves up and down in the shaft sleeve to drive the wafer adsorption mechanism to move up and down in the outer bracket of the large grinding fixture; An adsorption surface fixing plate is arranged below the upper substrate, three adsorption surfaces are fixed at the bottom of the adsorption surface fixing plate, and an arc-shaped groove compatible with the adsorption surfaces is arranged on the driving ring.

2. The multi-piece adsorption mechanism for the grinding fixture according to claim 1, characterized in that: The wafer adsorption mechanism also includes a vacuum duct and a guide plate. There are three vacuum ducts, which provide vacuum for three adsorption surfaces respectively and are arranged on one side of the upper substrate. The guide plate is located between the upper substrate and the adsorption surface fixing plate for vacuum conduction and sealing. The guide plate and the adsorption surface fixing plate are both provided with corresponding vacuum guide holes and vacuum grooves. The vacuum duct, vacuum guide holes and vacuum grooves form a vacuum channel to the adsorption surface. The front side of the adsorption surface is designed as a central through hole with a plurality of uniformly distributed radiation grooves. The central through hole is annularly grooved outwards, each annularly grooved with a guide hole, and each of the guide holes is connected to the vacuum channel through the central through hole.

3. The multi-piece adsorption mechanism for the grinding fixture according to claim 1, characterized in that: A middle barrier is arranged between the three adsorption surfaces, and an upper surface of the middle barrier is higher than upper surfaces of the three adsorption surfaces to form a height difference, and the height difference is smaller than the thickness of the glass substrate or sapphire substrate to which the crystal circle is bonded.

4. The multi-piece adsorption mechanism for the grinding fixture according to claim 2, characterized in that: The upper part of the shaft sleeve is connected with a pressure regulating nut through threads, and the lower part of the shaft sleeve is fixed with a micrometer through a bracket.

5. The multi-piece adsorption mechanism for the grinding fixture according to claim 4, characterized in that: The micrometer is located at a symmetrical position of the three vacuum tubes, so that the weight of the micrometer and the three vacuum tubes forms a left-right symmetrical balance.

6. The multi-piece adsorption mechanism for grinding fixture according to claim 1, characterized in that: Lifting rods are arranged on both sides of the upper base plate, and corresponding lock buckles are arranged on the fixing plate.

7. The multi-piece adsorption mechanism for grinding fixtures according to claim 1, characterized in that: A fixing block and a clamp connecting block are fixed on the upper part of the piston rod.

8. The multi-piece adsorption mechanism for grinding fixtures according to claim 1, characterized in that: The drive ring is made of wear-resistant metal material, wear-resistant ceramic material or electroplated diamond surface.

9. The multi-piece adsorption mechanism for grinding fixtures according to claim 1, characterized in that: The adsorption surface and the adsorption surface fixing plate are made of wear-resistant and corrosion-resistant metal or ceramic material.

10. The multi-piece adsorption mechanism for grinding fixtures according to claim 3, characterized in that: The middle partition is made of wear-resistant plastic material.

Images