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CN-122010535-A - Composite sintering process and surface modification method of alumina electrostatic chuck

CN122010535ACN 122010535 ACN122010535 ACN 122010535ACN-122010535-A

Abstract

The application discloses a composite sintering process and a surface modification method of an alumina electrostatic chuck, which belong to the technical field of electrostatic chucks and comprise the steps of preparing a substrate blank, namely selecting high-purity alumina ceramic powder, adding a sintering aid, mixing, and performing dry pressing to form the substrate blank, depositing an electrode layer, namely depositing a plurality of layers of composite electrodes on the surface of the substrate blank to form the electrode layer, coating a dielectric layer, namely coating an alumina film on the electrode layer, presintering, namely placing the substrate blank with a multi-layer structure in a sintering furnace for presintering, and performing composite sintering, wherein the composite sintering comprises the steps of vacuum sintering, pulse discharge plasma sintering, cooling, and cooling to room temperature at a speed of 1 ℃ per min so as to avoid thermal stress. Through the composite sintering process, the density of the electrostatic chuck after sintering is more than or equal to 99.8%, the grain size is thinned to be less than or equal to 200nm, and stable adsorption force can be maintained in a high-temperature environment with the temperature of more than 1400 ℃.

Inventors

  • LI JUN
  • CHENG LONG
  • SHI ZHEYUAN

Assignees

  • 君原电子科技(海宁)有限公司

Dates

Publication Date
20260512
Application Date
20251128

Claims (8)

  1. 1. A composite sintering process of an alumina electrostatic chuck, the composite sintering process comprising: Preparing a substrate blank, namely selecting high-purity alumina ceramic powder, adding 0.3-0.8% of rare earth oxide as a sintering aid, mixing, and performing dry pressing to form the substrate blank; depositing an electrode layer, namely depositing a plurality of layers of composite electrodes on the surface of the substrate blank to form an electrode layer with a grid pattern; coating a dielectric layer, namely coating an alumina film doped with titanium oxide on the electrode layer, wherein the thickness of the alumina film is 8-12 mu m so as to enhance the dielectric constant; Pre-sintering, namely placing the multi-layer structure blank in a nitrogen atmosphere sintering furnace, heating to 1000-1100 ℃ at the speed of 5 ℃ per minute, preserving heat for at least 2 hours, primarily removing internal pores, and performing low-temperature densification; composite sintering, comprising: the first stage, vacuum sintering, wherein the pressure is set to be less than or equal to 5Pa, the temperature is increased to 1500 ℃, and the heat is preserved for at least 30 minutes; the second stage, pulse discharge plasma sintering, wherein the pressure is 50MPa, the temperature is increased to 1550 ℃, the heat preservation is carried out for at least 15 minutes, and high-temperature strengthening is carried out; cooling to room temperature at a rate of 1 ℃ per minute to avoid thermal stress.
  2. 2. The composite sintering process of an alumina electrostatic chuck of claim 1, wherein the high purity alumina ceramic powder has a purity of 99.8% or more and the rare earth oxide is yttria or lanthana.
  3. 3. The composite sintering process of the alumina electrostatic chuck of claim 1, wherein the multi-layer composite electrode is formed by alternately depositing copper materials and molybdenum materials, the total thickness of the multi-layer composite electrode is 0.8-1.2 μm, the multi-layer composite electrode is a grid electrode pattern, and the grid side length of the grid pattern electrode layer is 0.2-0.5 mm.
  4. 4. The composite sintering process of an alumina electrostatic chuck of claim 1, wherein the pulse frequency of the pulse discharge plasma sintering is 2Hz, and the dynamic depressurization is performed at 10MPa every 5 minutes after the temperature is raised to 1550 ℃ for heat preservation.
  5. 5. A method of modifying a surface of an alumina electrostatic chuck, the method comprising the steps of: Forming a micron-sized honeycomb groove array on the surface of the dielectric layer by adopting a femtosecond laser etching technology; depositing a silicon nitride coating, namely depositing a silicon nitride film on the surface by plasma enhanced chemical vapor deposition to improve the plasma erosion resistance and the surface hardness; Polishing and cleaning, namely reducing the surface roughness to less than or equal to 0.1 mu m by using an ultra-precise polishing technology, and adopting ion beam cleaning to remove residual impurities.
  6. 6. The surface modification method of an alumina electrostatic chuck of claim 5, wherein the depth of the array of micro-scale honeycomb grooves is 5-10 μm and the pitch is 50 μm.
  7. 7. The surface modification method of an alumina electrostatic chuck according to claim 5, wherein the thickness of the silicon nitride film is 1 to 2 μm.
  8. 8. The method of claim 5, wherein the ultra-precise polishing technique is magneto-rheological polishing.

Description

Composite sintering process and surface modification method of alumina electrostatic chuck Technical Field The invention relates to the technical field of electrostatic chucks, in particular to a composite sintering process and a surface modification method of an alumina electrostatic chuck. Background The existing alumina electrostatic chuck has the following problems: 1. the traditional sintering process is difficult to achieve both high density and low energy consumption, so that the production cost is high and the performance is insufficient; 2. poor surface flatness, uneven adsorption force and influence on precision machining precision; 3. insufficient corrosion resistance is likely to cause structural damage in high temperature environments or plasma etching processes. Therefore, a new preparation technology with high performance and low cost is needed. Disclosure of Invention The invention aims to solve the technical problem of providing a composite sintering process and a surface modification method of an alumina electrostatic chuck, which can improve the compactness, the plasma erosion resistance and the surface hardness of the alumina electrostatic chuck. In order to solve the technical problems, the technical scheme of the invention is as follows: In one aspect, the present invention provides a composite sintering process for an alumina electrostatic chuck, the composite sintering process comprising: Preparing a substrate blank, namely selecting high-purity alumina ceramic powder, adding 0.3-0.8% of rare earth oxide as a sintering aid, mixing, and performing dry pressing to form the substrate blank; depositing an electrode layer, namely depositing a plurality of layers of composite electrodes on the surface of the substrate blank to form an electrode layer with a grid pattern; coating a dielectric layer, namely coating an alumina film doped with titanium oxide on the electrode layer, wherein the thickness of the alumina film is 8-12 mu m so as to enhance the dielectric constant; Pre-sintering, namely placing the multi-layer structure blank in a nitrogen atmosphere sintering furnace, heating to 1000-1100 ℃ at the speed of 5 ℃ per minute, preserving heat for at least 2 hours, primarily removing internal pores, and performing low-temperature densification; And (3) composite sintering: the first stage, vacuum sintering, wherein the pressure is set to be less than or equal to 5Pa, the temperature is increased to 1500 ℃, and the heat is preserved for at least 30 minutes; The second stage, pulse discharge plasma sintering, wherein the pressure is 50MPa, the temperature is increased to 1550 ℃, and the heat preservation is carried out for at least 15 minutes for high-temperature reinforcement; cooling to room temperature at a rate of 1 ℃ per minute to avoid thermal stress. Preferably, the purity of the high-purity alumina ceramic powder is greater than or equal to 99.8%, and the rare earth oxide is yttrium oxide or lanthanum oxide. Preferably, the multilayer composite electrode is formed by alternately depositing copper materials and molybdenum materials, the total thickness of the multilayer composite electrode is 0.8-1.2 mu m, the multilayer composite electrode is a grid-shaped electrode pattern, and the grid side length of the grid-shaped pattern electrode layer is 0.2-0.5 mm. Preferably, the pulse frequency of the pulse discharge plasma sintering is 2Hz, and the dynamic depressurization is carried out by reducing 10MPa every 5 minutes after the temperature is increased to 1550 ℃ for heat preservation. In another aspect, the present invention provides a surface modification method of an alumina electrostatic chuck, the surface modification method comprising the steps of: Forming a micron-sized honeycomb groove array on the surface of the dielectric layer by adopting a femtosecond laser etching technology; depositing a silicon nitride coating, namely depositing a silicon nitride film on the surface by plasma enhanced chemical vapor deposition to improve the plasma erosion resistance and the surface hardness; Polishing and cleaning, namely reducing the surface roughness to less than or equal to 0.1 mu m by using an ultra-precise polishing technology, and adopting ion beam cleaning to remove residual impurities. Preferably, the depth of the micron-sized honeycomb groove array is 5-10 μm, and the distance is 50 μm. Preferably, the thickness of the silicon nitride film is 1-2 μm. Preferably, the ultra-precise polishing technology is magnetorheological polishing. By adopting the technical scheme, the method has the following beneficial effects: Through the composite sintering process, the density of the sintered electrostatic chuck is more than or equal to 99.8%, the grain size is thinned to an average grain diameter of less than or equal to 200nm, the adsorption precision is less than or equal to +/-0.05 mu m, and the stable adsorption force can be maintained in a high-temperature environment with the temp