A method for maintaining concentricity between a pressure membrane and a steel ring inside the pressure membrane

Abstract

The present invention belongs to the field of chip processing technology, and specifically discloses a method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane, comprising the following steps: dust and oil removal of the steel ring, sandblasting of the steel ring surface, ultrasonic cleaning, blowing it clean after taking it out, and then baking it in an oven to remove moisture; pretreatment of the steel ring surface, immersing the steel ring in a silicone adhesive solution, taking it out and drying it; vacuum hot molding, after completing mold assembly on a flat-plate molding vulcanizer, placing a jig into the mold, placing the steel ring into the jig, and then placing 5 strips of silicone rubber onto the surface of the steel ring for vacuum hot molding; and quality inspection. The present invention adopts the above-mentioned method for maintaining concentricity of a pressure membrane and a steel ring inside the pressure membrane, and achieves the goal of preventing the steel ring from deforming and maintaining 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 cost of developing new products.

Description

Technical Field

[0001] The present 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] A wafer is a thin, round, high-purity silicon wafer used to manufacture silicon semiconductor circuits (chips). A chip is an integrated circuit manufactured on a wafer using a variety of semiconductor manufacturing processes, including photolithography, etching, and ion implantation. The wafer is the carrier and raw material for the chip, while the chip is the finished product with specific functions obtained after a series of processing steps.

[0003] During the wafer production process, wafers require grinding and polishing. The grinding head is a key component in performing these operations. The grinding head presses the wafer against the grinding or polishing pad through rotation and other motions, driving the wafer in rotation. Mechanical and chemical reactions remove excess material from the wafer surface or improve the wafer's surface quality, achieving the desired flatness and roughness.

[0004] During the chip grinding process, a gas connection to the grinding head assembly controls the pressure membrane's absorption and unloading of the wafer, causing the wafer to rub against the grinding pad, achieving the desired polishing effect. Existing pressure membranes are 0.7-0.9mm thick. Due to their thinness, the outermost edges have poor wear resistance, leading to membrane breakage and low efficiency. The pressure membrane is manufactured using vacuum hot molding, with a thin steel ring embedded within the membrane to improve the product's wear resistance. Because the steel ring is not positioned within the mold before molding, the rubber compound is squeezed to the edge of the mold immediately after the mold is closed and pressurized due to the flow of the rubber compound. This severely deforms the steel ring and makes it misaligned with the prepared pressure membrane. Because the embedded thin steel ring is not positioned correctly, the resulting pressure membrane embedded with the thin steel ring is not concentric with the outer diameter of the product. This causes uneven force on the grinding head when grinding the wafer, resulting in eccentricity. This reduces the qualified rate of the polished wafers and significantly affects 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 the surface of the steel ring to a roughness of 4.0>Ra>3.5, and ultrasonic cleaning for 10 minutes. After taking it out, blow it clean 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 it in a silicone adhesive solution. After the steel ring is completely soaked, take it out and dry it. After drying, put it in an oven to dry.

[0009] Step 3: Vacuum hot molding. After the mold is assembled on the flat-plate 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 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 any deformation or 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 positioning angles evenly distributed 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 5mm, one of the strip-shaped silicone rubber materials passes 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 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 forming 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 downward pressure to the steel ring at the moment of mold closing. Due to the increased friction between the steel ring and the mold surface, the steel ring is not affected by the impact of the rubber flow, 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 within the pressure membrane;

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

[0022] Figure 3 It is a schematic diagram of placing strip-shaped silicone rubber materials of the present invention.

[0023] Reference numerals

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

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

[0026] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" 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 object being described changes, the relative positional relationship may also change accordingly.

[0027] Example 1

[0028] A method for maintaining concentricity between 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 corundum 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, soak 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 compression molding. After completing mold assembly on a flat-plate vulcanizer, a ring-shaped fixture 4 is placed into the mold. The fixture 4 is annular, with evenly distributed positioning angles 3 on its upper surface. The steel ring 2 is positioned within the fixture 4. The steel ring 2 is placed within the fixture 4, and five strips of silicone rubber 5 are placed onto the surface of the steel ring 2 for vacuum hot compression molding. The strips of silicone rubber 5 are 10 mm wide and 3 mm thick. The flat-plate vulcanizer is set at 200°C for the upper mold and 190°C for the lower mold. The curing time is 400 seconds, and the feed pressure is 30 bar.

[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 as follows: 5 strip silicone rubber materials 5 are placed 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 extended 5mm, one strip silicone rubber material 5 passes 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 the center of the steel ring 2, and the placement interval of the 5 strip silicone rubber materials 5 is 30-40mm.

[0033] Step 4: Quality inspection: Use an optical magnifying glass to visually inspect the surface appearance of the product to see if the rubber coating 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. Then 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] The pressure membrane is manufactured using vacuum hot compression molding. The resulting circular pressure membrane requires placing a steel ring in the mold prior to compression molding and then hot-pressing it, embedding the steel ring within the pressure membrane. During vacuum hot compression molding of steel ring 2 within the mold, the mold core lacks a positioning groove. As the rubber material flows, steel ring 2 is squeezed to the edge of the mold immediately after the mold is closed and pressurized. This severely deforms the steel ring 2, causing it to be non-concentric with the compression-molded pressure membrane 1. Adjustments to the material placement and curing parameters are required to maintain concentricity and prevent deformation of steel ring 2.

[0035] To maintain uniform force above the steel ring 2, the strips of silicone rubber 5 forming the pressure membrane must be placed horizontally, with reasonable spacing and thickness. The empty space allows for the rubber to flow. The rubber above the steel ring 2 applies downward pressure to the steel ring 2 at the moment of mold closing. The increased friction between the steel ring 2 and the mold surface prevents the impact of the rubber flow, keeping the steel ring 2 stationary and prevented from shifting.

[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 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 solutions of the present invention rather than to limit the same. 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 solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions 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. Sandblast the surface of the steel ring to a roughness of 4.0>Ra>3.5, and then use ultrasonic cleaning for 10 minutes. After taking it out, blow it clean and bake it in an oven at 80 degrees for 10 minutes to remove moisture. The cross section of the steel ring is concave. Step 2: Pre-treat the surface of the steel ring by soaking it in a silicone adhesive solution. After the steel ring is completely soaked, take it out and dry it. After drying, put it in an oven to dry. Step 3: Vacuum hot molding. After the mold is assembled on the flat-plate 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 molding. The fixture is annular, with evenly distributed positioning angles on its upper surface along the circumference. The steel ring is located inside the fixture. The silicone strip is 10mm wide and 3mm thick. The operation of adding the silicone strip to the surface of the steel ring is as follows: five silicone strips are placed horizontally on the surface of the steel ring, with the two ends of the five silicone strips pressed to the edge of the steel ring and extending 5mm. One silicone strip passes through the center of the steel ring, and two silicone strips are placed on the upper and lower sides of the silicone strip passing through the center of the steel ring. The five silicone strips are placed at intervals of 30-40mm. 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 any deformation or 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: 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.

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 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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