Composite Sintered Electrostatic Chuck Material for High Withstand Voltage
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Solution Overview
Problem
Electrostatic chuck devices face challenges in maintaining high yield due to insulation breakdown and difficulty in removing wafers after plasma processing, exacerbated by the contradictory relationship between relative dielectric constant and withstand voltage, which affects temperature uniformity and deep drilling processing capabilities.
Innovation Solution
A composite sintered body comprising aluminum oxide as the main phase and silicon carbide as the sub-phase, with an interface layer and specific crystal grain size distribution, is used to enhance volume resistivity and withstand voltage, ensuring reliable electrostatic chucking and improved productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic material is used for the base to provide heat resistance and insulating properties, then the base can withstand high temperature plasma heating, but the material becomes easier to electrically conduct when heated, reducing the withstand voltage and causing insulation breakdown
Solution Approach 1:
The patent uses a composite sintered body comprising aluminum oxide (insulating phase) and silicon carbide (heat-resistant phase). This composite structure allows the base to maintain high heat resistance while preserving sufficient electrical insulation even at elevated temperatures, preventing the insulation breakdown that occurs with conventional single-phase ceramic materials.
2Force
If the relative dielectric constant of the base is increased to obtain high adsorption force for fixing the wafer, then the electrostatic attraction is enhanced, but the withstand voltage decreases due to the contradictory relationship between relative dielectric constant and withstand voltage
Solution Approach 1:
The composite sintered body of aluminum oxide and silicon carbide achieves an optimal balance between relative dielectric constant and withstand voltage. The aluminum oxide phase provides high dielectric constant for strong electrostatic adsorption, while the silicon carbide phase maintains electrical breakdown resistance, resolving the trade-off between adsorption force and withstand voltage.
3Temperature
If a gas refrigerant is supplied at high pressure to improve cooling efficiency and reduce in-plane temperature distribution, then temperature uniformity is enhanced, but the required adsorption force increases to prevent wafer detachment
Solution Approach 1:
The composite sintered body provides both the high relative dielectric constant needed for strong adsorption force and the thermal conductivity characteristics necessary for temperature uniformity. This allows the system to operate with high-pressure refrigerant cooling while maintaining sufficient wafer adsorption, as the composite material's electrical properties enable higher adsorption forces without compromising reliability.
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 composite sintered body achieves high relative dielectric constant and withstand voltage, facilitating efficient wafer removal and maintaining temperature uniformity, thus enhancing the productivity and reliability of electrostatic chuck devices in semiconductor manufacturing.
Implementation Method 1
the 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 the 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
This composite sintered body is a ceramic composite sintered body which includes aluminum oxide which is a main phase, and silicon carbide which is a sub-phase, the composite sintered body including an interface layer which includes, as a forming material, a material other than the aluminum oxide and the silicon carbide, at an interface between a crystal grain of the aluminum oxide and a crystal grain of the silicon carbide in a grain boundary.