Electrostatic Chuck Projection Curvature for Wear Resistance
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Solution Overview
Problem
Existing electrostatic chuck devices face issues with wear and temperature uniformity due to changes in the contact area between projection portions and samples, leading to uneven temperature distribution and sample deformation.
Innovation Solution
The electrostatic chuck device features convex projection portions with specific height and surface angle ratios, a chamfered R surface, and controlled surface roughness to maintain a consistent contact area and reduce wear, ensuring uniform temperature distribution across the sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If projection portions are provided on the placement surface to contact the plate-shaped sample, then temperature uniformity is improved, but the projection portions wear down due to repeated contact, changing the contact area
Solution Approach 1:
The invention applies curvature to the top surface of the projection portions by forming a convex curved surface with a specific radius of curvature (0.5mm to 2mm). This curved surface design ensures that even when wear occurs, the contact area changes minimally because the curvature distributes contact pressure and maintains a consistent contact region with the plate-shaped sample, thereby resolving the contradiction between achieving temperature uniformity and maintaining contact area stability.
2Ease of manufacture
If the top surface of projection portions is made flat (square shape), then manufacturing is easier, but corners wear down rapidly changing contact area
Solution Approach 1:
Instead of using flat top surfaces that are easy to manufacture but wear at corners, the invention employs convex curved surfaces with controlled radius of curvature. This approach prioritizes reliability by maintaining consistent contact area over time, while the curvature parameters are optimized to balance manufacturing feasibility with wear resistance.
3Reliability
If the top surface of projection portions is made arc-shaped, then wear resistance is improved, but the top surface is still easily worn by contact
Solution Approach 1:
The invention optimizes specific parameters of the convex curved surface, including the radius of curvature (0.5mm to 2mm) and the angle formed by the curved surface (90° to 160°). These parameter adjustments ensure that the projection portions provide sufficient contact area for temperature uniformity while maintaining wear resistance through the convex geometry that distributes mechanical stress.
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 minimizes changes in the contact area even with wear, maintaining excellent temperature uniformity and preventing sample deformation, thus stabilizing the temperature of the plate-shaped sample over time.
Implementation Method 1
applies a voltage between the plate-shaped sample and an internal electrode for electrostatic attraction to generate electrostatic attraction force, and as a result, the plate-shaped sample is attracted and fixed to an attraction surface of the ceramic plate-shaped body by the electrostatic attraction force
Implementation Method 2
an inert gas such as helium is flowed between an attraction surface of a ceramic plate-shaped body and a plate-shaped sample to cool the plate-shaped sample in order to control the temperature of the plate-shaped sample during processing or treatment
Data Source
AI summary
According to an electrostatic chuck device of the present invention, a cross-sectional shape of a base body in a thickness direction is a convex curved surface or a concave curved surface that gradually curves from a center of one main surface toward an outer periphery of the one main surface, an annular projection portion is provided on a peripheral portion on the one main surface of the base body so as to go around the peripheral portion, a plurality of convex projection portions are provided in a region surrounded by the annular projection portion, the convex projection portion has the top surface in contact with the plate-shaped sample, a side surface, and an R surface continuously connecting the top surface and the side surface.