CN-121974698-A - Silicon carbide bump vacuum chuck processing method

Abstract

The application discloses a silicon carbide bump vacuum chuck processing method, which aims to solve the defects of poor bump strength, easy falling off and low yield of a vacuum chuck. The method comprises the following steps of S1, forming a ceramic biscuit, S2, rough machining the ceramic biscuit, S3, degreasing the ceramic biscuit to form a porous biscuit, S4, sintering, S5, finish machining, grinding the bump machining surface of a sintered semi-finished product, S6, laser machining a plurality of bumps on the ground bump machining surface, S7, polishing the end surface of the bumps to form a vacuum chuck, and S8, cleaning the vacuum chuck. The vacuum chuck processing method shortens the processing period, improves the working efficiency, reduces the cost and provides the qualification rate of products.

Inventors

• SUN ZHONGHUI
• MA YUQI

Assignees

• 杭州大和江东新材料科技有限公司

Dates

Publication Date

20260505

Application Date

20251230

Claims (10)

1. 1. A method for machining a silicon carbide bump vacuum chuck is characterized by comprising the following steps of S1, forming a ceramic biscuit, S2, roughly machining the ceramic biscuit, S3, degreasing the ceramic biscuit to form a porous biscuit, S4, sintering, S5, finely machining, grinding the bump machining surface of a sintered semi-finished product, S6, laser machining a plurality of bumps on the ground bump machining surface, S7, polishing the end surface of the bump to form the vacuum chuck, and S8, cleaning the vacuum chuck.
2. 2. The method for processing the silicon carbide bump vacuum chuck according to claim 1, wherein the S1 ceramic biscuit is formed by cold isostatic pressing of silicon carbide granulated powder.
3. 3. The method for processing the silicon carbide bump vacuum chuck according to claim 2, wherein the silicon carbide granulated powder has a D50 of 100+/-5 μm, a water content of 0.6-1.2%, a bulk density of 0.8-0.9 g/cm < 3 >, a cold isostatic pressing pressure of 100-130 MPa, a molding time of 2-5 minutes, and a density of 1.70-1.90 g/cm 3 of a ceramic biscuit after molding.
4. 4. The method for processing the silicon carbide bump vacuum chuck according to claim 1, wherein the S3 degreasing atmosphere is nitrogen, the degreasing temperature is 550-650 ℃, and the heat preservation time is 3-8 hours.
5. 5. The method for processing the silicon carbide bump vacuum chuck according to claim 1, wherein the S4 sintering atmosphere is argon, the sintering temperature is 2100-2150 ℃, and the heat preservation time is 3-6 h.
6. 6. The method for processing the silicon carbide bump according to claim 1, wherein S6 is a layered processing method, and each layer is cooled at intervals after the completion of the processing, and the laser processing speed is sequentially reduced.
7. 7. The method for processing the silicon carbide bump vacuum chuck according to claim 1, wherein the step S7 is performed by using a mixed solution of diamond micro powder and pure water as the polishing liquid.
8. 8. The method for processing the silicon carbide salient point vacuum chuck according to claim 1, wherein S8 is characterized in that hydrofluoric acid, nitric acid and water are used for preparing mixed acid liquid according to a certain proportion, the vacuum chuck is placed in the mixed acid liquid for soaking for 15-30 minutes, pure water is used for flushing a product at least 3 times after the vacuum chuck is taken out, and the concentration of the hydrofluoric acid in the mixed acid liquid is 14% -20%, and the concentration of the nitric acid in the mixed acid liquid is 17% -30%.
9. 9. The method for machining the silicon carbide bump according to any one of claims 1 to 8, wherein S2 is a clamping tool for clamping and positioning the ceramic biscuit, the clamping tool comprises a support boss, the ceramic biscuit is loaded on the support boss, an adjusting ring is rotatably connected to the periphery of the support boss, a plurality of radially moving positioning clamp arms are circumferentially arranged on the support boss at intervals, circumferentially inclined pushing grooves are formed in the adjusting ring, pushing columns are arranged on the positioning clamp arms, the pushing columns and the pushing grooves are movably inserted, the adjusting ring rotates to enable the pushing grooves to push the pushing columns, and the positioning clamp arms radially move to clamp the ceramic biscuit.
10. 10. The method for processing the silicon carbide salient point vacuum chuck is characterized in that a radially moving gesture adjusting plate is arranged on a supporting boss, the end part of the gesture adjusting plate is of a conical structure, U-shaped grooves are processed on the surface of a ceramic biscuit in S2, clamping and positioning are carried out on semi-finished products by adopting clamping tools in S5, S6 and S7, and the gesture adjusting plate is radially moved and inserted into the U-shaped grooves to realize gesture adjusting and positioning of the semi-finished products.

Description

Silicon carbide bump vacuum chuck processing method Technical Field The invention relates to the technical field of vacuum chuck processing, in particular to a silicon carbide bump vacuum chuck processing method. Background Silicon carbide bump vacuum chuck is a key component in the semiconductor measurement field to ensure that the wafer can be stably, accurately and atraumatically fixed and measured. The wafer suction device can provide a stable adsorption platform with high flatness, reduce wafer deformation and ensure measurement repeatability and accuracy. The bump design on the vacuum chuck disperses stress to avoid wafer cracking or hidden cracking caused by overlarge local pressure. The high heat-conducting property of the silicon carbide material can rapidly lead out the heat of the wafer, ensure the temperature stability in the measuring process and prevent the thermal deformation from affecting the measuring result. Silicon carbide ceramics are resistant to strong alkali and corrosive chemicals, have compact and smooth surfaces, are not easy to generate particles, and meet the severe requirements of semiconductor measurement on cleanliness. The prior silicon carbide ceramic sucker surface salient point structure is mainly prepared by CNC processing. In the manufacturing process, as the diameter of the bump design is smaller and smaller, the silicon carbide ceramic is high in hardness and fragile, and the bump is broken easily due to the shaking force of the grinding head tool in the processing process, so that the incomplete and uneven bump design on the surface of the whole sucker is caused. The silicon carbide ceramic has high hardness, difficult processing, high processing cost and long processing time, and the yield of the bump structure is extremely low. Chinese patent application number 2024100179161 discloses a preparation method of a salient point silicon carbide ceramic sucker, wherein the salient points on the silicon carbide surface are processed in a dispensing mode, and the salient points obtained in the processing mode have poor strength, are easy to fall off and have low yield. Disclosure of Invention In order to overcome the defects, the invention provides the silicon carbide bump vacuum chuck processing method, which shortens the processing period of the vacuum chuck, improves the working efficiency, reduces the cost and provides the qualification rate of products. The technical scheme includes that the silicon carbide bump vacuum chuck machining method comprises the following steps of S1, forming a ceramic biscuit, S2, roughly machining the ceramic biscuit, S3, degreasing the ceramic biscuit to form a porous biscuit, S4, sintering, S5, finely machining the bump machining surface of a sintered semi-finished product, S6, machining a plurality of bumps on the ground bump machining surface by laser, S7, polishing the end faces of the bumps to form a vacuum chuck, and S8, cleaning the vacuum chuck. In the vacuum chuck processing process, the green body after ceramic biscuit shaping carries out rough machining, and the rough machining size of the green body is confirmed according to sintering shrinkage and product design size during rough machining, directly processes most structures such as U-shaped grooves, reinforcing ribs, bosses, vent holes and the like on the surface of the green body in place. And degreasing, and placing the green body in a degreasing furnace for glue discharging and presintering to obtain the porous biscuit. And then sintering, namely placing the blank body into a vacuum sintering furnace to obtain a pressureless sintered silicon carbide ceramic semi-finished product with large size and complex shape, wherein the structures such as the U-shaped groove, the reinforcing rib, the boss, the vent hole and the like are sintered in place. During finish machining, only the bump machining surface of the sintered semi-finished product is subjected to grinding machining with a small allowance, other surfaces do not need machining, and the working efficiency is high. The laser processing convex points are uniformly distributed on the vacuum chuck, the number of the convex points is about 3000, the diameter of the convex points is 0.8+/-0.02 mm, the height is 0.2+/-0.005+/-mm, and the laser processing precision is high. Polishing the bumps after laser processing to obtain high-precision silicon carbide ceramic, cleaning the silicon carbide bump vacuum chuck, and reducing metal ion pollution. According to the invention, the molding shrinkage rate and the sintering shrinkage rate are accurately controlled, most structures such as the U-shaped groove, the reinforcing rib, the boss and the like of the green body are directly machined in place, and then sintered in place, so that long-time finish machining is not needed, the manufacturing period is shortened, the finish machining cost of the ceramic sucker is reduced, and the ceramic sucker is convenient for industrial producti