Electrostatic Chuck Segmented Conductor Film
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Solution Overview
Problem
Conventional electrostatic chucks face issues with insufficient chucking force due to the absence of Johnson-Rahbeck force and unstable substrate separation, primarily because the conductor line covering the substrate supporting surfaces is removed, leading to delayed charge removal and complex wiring structures, and using different insulating materials can trap electric charge, causing residual chucking forces and unstable separation.
Innovation Solution
An electrostatic chuck with a dielectric board featuring projections and recesses, an internal electrode, and a conductor film on the projections' surfaces with a three-dimensional structure (Ry ≤ 2.5 μm and Ra ≤ 0.25 μm) that generates both spatial Coulomb and Johnson-Rahbeck forces for sufficient holding and rapid unloading, eliminating residual forces by equalizing potential between the substrate and conductor film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the conductor line covering the substrate supporting surfaces is removed to allow Johnson-Rahbeck force to act, then the chucking force is improved, but the substrate separation time increases and the wiring structure becomes complex
Solution Approach 1:
The conductor line is segmented into isolated conductor portions, each corresponding to an individual projection, rather than being a continuous line. This segmentation allows the conductor to be directly connected to ground potential, enabling rapid charge removal while maintaining the Johnson-Rahbeck force effect through the rough surface structure.
Solution Approach 2:
The conductor portions are directly connected to ground potential, creating equipotential conditions between the conductor and substrate supporting surfaces. This eliminates potential differences that would otherwise delay charge removal, allowing rapid substrate separation while maintaining sufficient chucking force during operation.
2Force
If the conductor line covering the substrate supporting surfaces is removed to allow Johnson-Rahbeck force to act, then the chucking force is improved, but the wiring structure becomes complex
Solution Approach 1:
The conductor line is divided into separate conductor portions for each projection, eliminating the need for continuous wiring structures. Each conductor portion is independently connected to ground, simplifying the overall wiring architecture while enabling the Johnson-Rahbeck force to act effectively.
Solution Approach 2:
The conductor line is extracted and replaced with discrete conductor portions that are directly grounded. This extraction eliminates the complex continuous wiring structure while preserving the essential function of charge removal and enabling Johnson-Rahbeck force generation.
3Force
If a material different from the electrostatic chuck material is used as insulating material, then the chucking force is improved, but electric charge is trapped and substrate separation becomes unstable
Solution Approach 1:
The insulating material and electrostatic chuck are made of the same material, creating homogeneous material composition throughout the structure. This homogeneity prevents charge trapping at material interfaces, ensuring stable and reliable substrate separation while maintaining sufficient chucking force during operation.
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 electrostatic chuck achieves a sufficient holding force through combined spatial Coulomb and Johnson-Rahbeck forces, enabling rapid and stable substrate unloading by ensuring smooth conductor films with increased contact points and high wear resistance, suppressing particle generation and simplifying the structure.
Implementation Method 1
The substrate is held by the spatial Coulomb force between the recesses of the upper surface of the dielectric board and the lower surface of the substrate
Implementation Method 2
the Johnson-Rahbeck force acting between the conductor film on the projection of the upper surface of the dielectric board and the lower surface of the substrate
Data Source
AI summary
An electrostatic chuck includes a dielectric board having an upper surface on which a plurality of projections for supporting a substrate on top surfaces and recesses surrounding the projections are formed, an electrode formed inside the dielectric board, and an external power supply which applies a voltage to the electrode. The dielectric board includes a conductor film formed on at least the top surface of each projection, and has a three-dimensional structure which causes the conductor film to generate a Johnson-Rahbeck force between the substrate and conductor film when a voltage is applied to the electrode.