Electrostatic Chuck Base Material High Temperature Resistivity
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Solution Overview
Problem
Existing electrostatic chuck devices face difficulties in easily removing wafers at high temperatures due to decreased volume resistivity of the base material, leading to persistent electrostatic forces and potential dielectric breakdown, which affects work efficiency and yield in semiconductor manufacturing.
Innovation Solution
An electrostatic chuck device with a base made from a sintered compact of ceramic particles, including silicon carbide and aluminum oxide, with a volume resistivity of 0.5×10^15 Ωcm or more from 24° C. to 300° C., and a dielectric breakdown strength at 180° C. that is at least 0.85 times the strength at 24° C., minimizing metal impurities to prevent dielectric breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the base is heated to high temperature for plasma process, then the heating function is achieved, but the volume resistivity decreases causing difficulty in wafer removal
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the composition ratios of ceramic particles (silicon carbide, aluminum oxide, aluminum nitride) and metal impurities in the base material. By optimizing these parameters, the base achieves high temperature resistance while maintaining appropriate volume resistivity characteristics that allow easy wafer removal even at elevated temperatures.
Solution Approach 2:
The patent uses composite materials by combining multiple ceramic particles (silicon carbide, aluminum oxide, aluminum nitride) with controlled metal impurity content. This composite structure provides both high temperature resistance for plasma processing and controlled electrical properties for easy wafer removal, resolving the contradiction between heating function and ease of operation.
2Force
If the volume resistivity decreases at high temperature, then electrostatic force generation becomes easier, but depolarization becomes difficult leading to persistent attraction force
Solution Approach 1:
The patent controls the volume resistivity parameter through precise composition design of ceramic particles and metal impurities. The base is engineered to maintain optimal volume resistivity across the temperature range, ensuring that electrostatic force generation is effective during processing while depolarization occurs readily after voltage cessation, enabling easy wafer removal.
3Temperature
If the base material is heated to high temperature, then plasma process is enabled, but dielectric breakdown may occur reducing yield
Solution Approach 1:
The patent employs composite materials consisting of silicon carbide particles, aluminum oxide particles, and aluminum nitride particles with controlled metal impurity content. This composite structure provides high temperature resistance and enhanced dielectric strength, preventing dielectric breakdown during plasma processing and maintaining high yield.
Solution Approach 2:
The patent optimizes the composition parameters including particle types, size distributions, and metal impurity levels to achieve the desired dielectric breakdown strength at high temperatures. By controlling these parameters, the base material maintains sufficient dielectric properties even at plasma processing temperatures, ensuring reliability and high yield.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables easy wafer removal at high temperatures and improves the yield of plasma treatment by maintaining sufficient electrostatic forces and preventing dielectric breakdown, thus enhancing the efficiency and reliability of semiconductor processing.
Implementation Method 1
an electrostatic attraction electrode that generates an electrostatic force (Coulomb's force) between a base having one principal surface which is a pacing surface on which a wafer is placed, and the wafer placed on the placing surface
Implementation Method 2
the base on which the wafer is placed is heated to a high temperature by plasma
Data Source
AI summary
An electrostatic chuck device includes: a base having one principal surface which is a placing surface on which a plate-shaped sample is placed, wherein the base is made from a sintered compact of ceramic particles, which include silicon carbide particles and aluminum oxide particles, as a forming material; and an electrostatic attraction electrode which is provided on a surface of the base on the side opposite to the placing surface of the base, or in the interior of the base, in which the volume resistivity value of the sintered compact is 0.5×1015 Ωcm or more in the entire range from 24° C. to 300° C., a graph which shows the relationship of the volume resistivity value of the sintered compact to a temperature at which the volume resistivity value of the sintered compact is measured has a maximum value in the range from 24° C. to 300° C., and the amount of metal impurities in the sintered compact other than aluminum and silicon in the sintered compact is 100 ppm or less.