Electrostatic Chuck Porous Structure Arc Discharge
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Solution Overview
Problem
Electrostatic chucks used in processing substrates face challenges in preventing arc discharge while maintaining mechanical strength and gas flow efficiency, particularly due to the limitations of existing porous structures in the gas introduction paths and through holes.
Innovation Solution
The electrostatic chuck incorporates a porous structure with sparse and dense regions, where the sparse regions have smaller holes and a higher porosity, and the dense regions provide increased mechanical strength, optimizing the balance between arc discharge resistance and gas flow rate by controlling the dimensions and arrangement of pores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous part is provided in the gas introduction path to improve resistance to arc discharge, then arc discharge resistance is improved, but mechanical strength of the porous part deteriorates
Solution Approach 1:
The porous part is designed with non-uniform pore distribution, creating sparse portions with smaller holes and higher porosity for arc discharge resistance, and dense portions with larger holes and lower porosity for mechanical strength. This local quality variation allows different regions to optimize for their specific functions simultaneously
Solution Approach 2:
The porous part functions as a composite structure combining regions of different porosity levels, effectively integrating the arc discharge protection function (sparse portions) with the structural support function (dense portions) within a single component
2Reliability
If holes are made smaller to improve arc discharge resistance, then arc discharge resistance is improved, but gas flow rate deteriorates
Solution Approach 1:
The porous part implements spatially varying pore characteristics: sparse portions contain smaller holes for arc discharge resistance, while dense portions contain larger holes for gas flow efficiency. This local differentiation resolves the contradiction between hole size and its dual functions
Solution Approach 2:
The porous part is segmented into functionally distinct sparse and dense portions, allowing independent optimization of pore sizes for different purposes - small pores in sparse regions for electrical insulation, large pores in dense regions for fluid transport
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
This design effectively suppresses arc discharge and enhances the mechanical strength of the porous part, ensuring high resistance to arc discharge while maintaining efficient gas flow and temperature control during substrate processing.
Implementation Method 1
discharge (arc discharge) from the plasma in the apparatus toward the base plate made of a metal may be generated
Implementation Method 2
an inactive gas such as He or the like is flown between the ceramic dielectric substrate and the substrate being the suction object, and the temperature increase of the substrate is suppressed by bringing the inactive gas into contact with the substrate
Implementation Method 3
applies an electrostatic suction power to built-in electrodes and sucks a substrate such as a silicon wafer or the like by an electrostatic force
Data Source
AI summary
According to the embodiment, the first invention relates to an electrostatic chuck. The electrostatic chuck includes a ceramic dielectric substrate having a first major surface placing a suction object and a second major surface on an opposite side to the first major surface, a base plate supporting the ceramic dielectric substrate and including a gas introduction path, and a first porous part provided at a position between the base plate and the first major surface and being opposite to the gas introduction path. The first porous part includes sparse portions including pores and a dense portion having a density higher than a density of the sparse portions. Each of the sparse portions extends from the base plate toward the ceramic dielectric substrate. The dense portion is positioned between the sparse portions. The sparse portions include a wall portion provided between the pores and the pores.