Method for keeping concentricity of pressure film and steel ring in pressure film

Abstract

The invention belongs to the technical field of chip processing, and particularly discloses a method for keeping concentricity of a pressure film and a steel ring in the pressure film, which comprises the following steps: carrying out dust and oil removal treatment on the steel ring, carrying out sand blasting treatment on the surface of the steel ring, carrying out ultrasonic cleaning, taking out, blowing clean, baking with an oven, and removing moisture; the surface of the steel ring is pretreated, and the steel ring is soaked in a silicon adhesive solution, taken out and dried; vacuum hot compression molding: after mold assembly is completed on a flat plate molding vulcanizing machine, a jig is put into a mold, a steel ring is put into the jig, and then five strip-shaped silica gel materials are put into the surface of the steel ring for vacuum hot compression molding; and quality detection. According to the method for keeping the concentricity of the pressure film and the steel ring in the pressure film, the steel ring does not deform and keeps the concentricity by changing a material placing mode and equipment parameters, wafer grinding is prevented from being affected, meanwhile, a mold does not need to be opened or modified again, and the purpose of reducing the research and development cost of new products is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of chip processing, in particular to a method for maintaining concentricity between a pressure membrane and a steel ring inside the pressure membrane. Background Art

[0002] Wafer refers to the silicon wafer used to make silicon semiconductor circuits (chips). It is a thin, round, high-purity silicon wafer. Chips are integrated circuits made on wafers using a variety of semiconductor manufacturing processes such as photolithography, etching, and ion implantation. Wafers are the carrier and raw material of chips, and chips are finished products with specific functions obtained after a series of processing of wafers.

[0003] During the production process of wafers, the wafers need to be ground and polished. The grinding head is one of the key components to perform this operation. The grinding head presses the wafer on the grinding pad or polishing pad through rotation and other movements, and drives the wafer to rotate, using mechanical force and chemical action to remove excess material on the wafer surface or improve the surface quality of the wafer, so that the wafer reaches the required flatness and roughness.

[0004] During the chip grinding process, the gas is connected to the grinding head assembly to control the adsorption and unloading of the pressure membrane on the wafer, so that the wafer rubs on the grinding pad to achieve the purpose of polishing. The existing pressure membrane thickness is 0.7-0.9mm. Because it is relatively thin, the outermost edge has poor wear resistance, resulting in membrane damage and low efficiency. The pressure membrane is prepared by vacuum hot molding, and a thin steel ring is embedded in the pressure membrane to improve the wear resistance of the product. Because the steel ring is not positioned in the mold before molding, the rubber is squeezed to the edge of the mold due to the flow of the rubber at the moment when the mold is closed and pressurized. The steel ring is severely deformed and cannot be concentric with the prepared pressure membrane. Because the embedded thin steel ring is not positioned, the pressure membrane embedded with thin steel ring products produced is not concentric with the outer diameter of the product, causing uneven force on the grinding head when grinding the wafer, eccentricity occurs, resulting in a decrease in the qualified rate of the ground wafer, greatly affecting the improvement of production capacity. Summary of the invention

[0005] The purpose of the present invention is to provide a method for maintaining the concentricity of a pressure membrane and a steel ring inside the pressure membrane. By changing the material swinging method and equipment parameters, the steel ring can be kept from deforming and maintaining concentricity, thereby avoiding affecting the grinding of the wafer. At the same time, there is no need to reopen the mold or modify the mold, thereby achieving the purpose of reducing the R&D cost of developing new products.

[0006] To achieve the above object, the present invention provides a method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane, comprising the following steps:

[0007] Step 1: Dust and oil removal of the steel ring, sandblasting of the steel ring surface to make the roughness reach 4.0>Ra>3.5, and ultrasonic cleaning for 10 minutes, blow it clean after taking it out, and bake it in an oven at 80 degrees for 10 minutes to remove moisture;

[0008] Step 2: Pre-treat the surface of the steel ring by soaking the steel ring in the silicone adhesive solution, taking it out and drying it after it is completely soaked, and then putting it in the oven to dry;

[0009] Step 3: vacuum hot compression molding. After the mold assembly is completed on the flat molding vulcanizer, the jig is placed into the mold, the steel ring is placed into the jig, and then 5 strips of silicone rubber are placed on the surface of the steel ring for vacuum hot compression molding.

[0010] Step 4: Quality inspection: Use an optical magnifying glass to visually inspect the product surface appearance, use a 3D scanner to detect whether the surface of the steel ring inside the membrane is flat, whether there is deformation and sagging of the pressure membrane, and then use a 2D projector to measure the concentricity of the steel ring and the pressure membrane.

[0011] Preferably, the cross section of the steel ring is concave.

[0012] Preferably, in step one, the sandblasting treatment is: first use 60-mesh fine corundum to remove stains on the product surface, then use 36-mesh corundum to increase the surface roughness, and finally use 24-mesh corundum to sandblast the surface.

[0013] Preferably, in step three, the jig is annular, the upper surface is provided with evenly distributed positioning angles along the circumference, and the steel ring is located inside the jig.

[0014] Preferably, in step three, the strip of silicone rubber has a width of 10 mm and a thickness of 3 mm.

[0015] Preferably, in step three, the operation of putting the strip-shaped silicone rubber into the surface of the steel ring is: 5 strip-shaped silicone rubber materials are placed horizontally on the surface of the steel ring, and the two ends of the 5 strip-shaped silicone rubber materials are pressed to the edge of the steel ring and extended by 5mm, one of the strip-shaped silicone rubber materials passes through the center of the steel ring, and two strip-shaped silicone rubber materials are provided on the upper and lower sides of the strip-shaped silicone rubber material passing through the center of the steel ring, and the 5 strip-shaped silicone rubber materials are placed at an interval of 30-40mm.

[0016] Preferably, in step three, the upper mold of the flat-plate molding vulcanizer is set at 200° C., the lower mold is set at 190° C., the vulcanization time is 400 seconds, and the feed pressure is 30 bar.

[0017] The advantages and beneficial effects of the method for maintaining concentricity of the pressure membrane and the steel ring inside the pressure membrane by the present invention are:

[0018] In order to maintain uniform force above the steel ring, the rubber must be placed horizontally with reasonable spacing and appropriate thickness. The empty area is used for the flow of the rubber. The rubber on the upper part of the steel ring applies a downward pressure to the steel ring at the moment of mold closing. The friction between the steel ring and the mold surface increases and is not affected by the impact of the flow of the rubber, so the steel ring is kept stationary and does not deviate, thereby maintaining concentricity with the pressure membrane.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of the steel ring of the present invention in the pressure membrane;

[0021] Figure 2 is a schematic cross-sectional view of a steel ring of the present invention;

[0022] Figure 3 It is a schematic diagram of placing strip-shaped silicone rubber material of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 1. Pressure membrane; 2. Steel ring; 3. Positioning angle; 4. Jig; 5. Strip silicone rubber. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Example 1

[0028] A method for maintaining concentricity of a pressure membrane and a steel ring 2 inside the pressure membrane, comprising the following steps:

[0029] Step 1: First use 60 mesh fine corundum to remove stains on the surface of the product, then use 36 mesh to increase the surface roughness, and finally use 24 mesh corundum to sandblast the surface to a roughness of 4.0>Ra>3.5, and use ultrasonic cleaning for 10 minutes to remove the oil stains on the surface of the steel ring 2. After taking it out, blow it clean and bake it in an oven at 80 degrees for 10 minutes to remove moisture. Figure 1 and Figure 2 As shown, the cross section of the steel ring 2 is concave, which increases the contact surface area and improves the adhesion.

[0030] Step 2: Pre-treat the surface of the steel ring 2. The cleaned steel ring 2 needs to be dried in a 100-degree oven for 8 minutes. After taking it out and cooling it, immerse the steel ring 2 in a silicone adhesive solution. After the steel ring 2 is completely soaked, take it out and dry it. After drying, put it in a 120-degree oven and bake it for 5 minutes.

[0031] Step 3: Vacuum hot molding. After the mold assembly is completed on the flat molding vulcanizer, the jig 4 is placed into the mold. The jig 4 is annular, and the upper surface is provided with evenly distributed positioning angles 3 along the circumference. The steel ring 2 is located inside the jig 4. The steel ring 2 is placed in the jig 4, and then 5 strips of silicone rubber 5 are placed on the surface of the steel ring 2 for vacuum hot molding; the strips of silicone rubber 5 are 10mm wide and 3mm thick. The upper mold of the flat molding vulcanizer is set at 200℃, the lower mold is set at 190℃, the vulcanization time is 400S, and the feed pressure is 30bar.

[0032] like Figure 3 As shown, the operation of putting the strip silicone rubber material 5 into the surface of the steel ring 2 is: place 5 strip silicone rubber materials 5 horizontally on the surface of the steel ring 2, and the two ends of the 5 strip silicone rubber materials 5 are pressed to the edge of the steel ring 2 and extend 5mm, one of the strip silicone rubber materials 5 passes through the center of the steel ring 2, and two strip silicone rubber materials 5 are provided on the upper and lower sides of the strip silicone rubber material 5 passing through the center of the steel ring 2, and the 5 strip silicone rubber materials 5 are placed at an interval of 30-40mm.

[0033] Step 4: Quality inspection: Use an optical magnifying glass to visually inspect the product surface to see if the rubber encapsulation is complete. Use a 3D scanner to detect whether the surface of the steel ring 2 inside the membrane is flat, and whether there is any deformation or sagging of the pressure membrane 1. Use a 2D projector to measure the concentricity of the steel ring 2 and the pressure membrane 1 to ensure that the thin steel ring 2 is not deformed, the membrane and the steel ring 2 are concentric and not offset, so that the product will not be eccentric during use.

[0034] When preparing the pressure membrane, vacuum hot molding is adopted. The prepared pressure membrane is round. It is necessary to put the steel ring into the mold before molding, and then hot molding, so that the steel ring is embedded in the pressure membrane. When the steel ring 2 is vacuum hot molded in the mold, because the mold core does not have a positioning groove for the mold, the rubber material is squeezed to the edge of the mold due to the flow of the rubber material at the moment when the mold is closed and pressurized, and the steel ring 2 is severely deformed, resulting in the steel ring and the molded pressure membrane 1 not being concentric. It is necessary to change the material swinging method and vulcanization parameters to maintain the concentricity and non-deformation of the steel ring 2.

[0035] In order to keep the force on the steel ring 2 uniform, the strip-shaped silicone rubber material 5 used to prepare the pressure film must be placed horizontally with reasonable spacing and appropriate thickness. The empty area is used for the flow of the rubber material. The rubber material on the steel ring 2 gives the steel ring 2 a downward pressure at the moment of mold closing. The friction between the steel ring 2 and the mold surface increases, and the impact force of the rubber material flow is not affected, so the steel ring 2 is kept motionless and does not deviate.

[0036] Therefore, the present invention adopts the above-mentioned method of maintaining concentricity of the pressure membrane and the steel ring inside the pressure membrane, and realizes that the steel ring does not deform and maintains concentricity by changing the material swinging method and equipment parameters, thereby avoiding affecting the grinding of the wafer. At the same time, there is no need to reopen the mold or modify the mold, thereby achieving the purpose of reducing the R&D cost of developing new products.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for maintaining concentricity between a pressure membrane and a steel ring inside the pressure membrane, characterized in that: The steps include: Step 1: Dust and oil removal of the steel ring, sandblasting of the steel ring surface to make the roughness reach 4.0>Ra>3.5, and ultrasonic cleaning for 10 minutes, blow it clean after taking it out, and bake it in an oven at 80 degrees for 10 minutes to remove moisture; Step 2: Pre-treat the surface of the steel ring by soaking the steel ring in the silicone adhesive solution, taking it out and drying it after it is completely soaked, and then putting it in the oven to dry; Step 3: vacuum hot compression molding. After the mold assembly is completed on the flat molding vulcanizer, the jig is placed into the mold, the steel ring is placed into the jig, and then 5 strips of silicone rubber are placed on the surface of the steel ring for vacuum hot compression molding. Step 4: Quality inspection: Use an optical magnifying glass to visually inspect the product surface appearance, use a 3D scanner to detect whether the surface of the steel ring inside the membrane is flat, whether there is deformation and sagging of the pressure membrane, and then use a 2D projector to measure the concentricity of the steel ring and the pressure membrane.

2. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: The cross section of the steel ring is concave.

3. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: In step 1, the sandblasting treatment is as follows: first use 60-mesh fine corundum to remove stains on the product surface, then use 36-mesh corundum to increase the surface roughness, and finally use 24-mesh corundum to sandblast the surface.

4. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: In step three, the jig is annular, the upper surface is provided with evenly distributed positioning angles along the circumference, and the steel ring is located inside the jig.

5. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: In step three, the width of the strip silicone rubber is 10 mm and the thickness is 3 mm.

6. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: In step three, the operation of putting the strip silicone rubber into the surface of the steel ring is as follows: 5 strip silicone rubber materials are placed horizontally on the surface of the steel ring, and the two ends of the 5 strip silicone rubber materials are pressed to the edge of the steel ring and extended by 5mm, one of the strip silicone rubber materials passes the center of the steel ring, and two strip silicone rubber materials are arranged on the upper and lower sides of the strip silicone rubber material passing the center of the steel ring, and the 5 strip silicone rubber materials are placed at an interval of 30-40mm.

7. The method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane according to claim 1, characterized in that: In step 3, the upper mold of the flat plate forming vulcanizer is set at 200°C, the lower mold is set at 190°C, the vulcanization time is 400S, and the feed pressure is 30bar.

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