Electrostatic Chuck Ceramic Layout to Suppress Groove Discharge
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Solution Overview
Problem
The existing electrostatic chucks with uneven placement surfaces are prone to electric discharge due to a short distance between the electrostatic electrode and the base body, leading to potential electrical discharges, especially when the ceramics used have low resistance and density issues.
Innovation Solution
The electrostatic chuck incorporates a high-resistance region made of ceramics with a volume resistivity higher than the low-resistance region, arranged between the groove and the electrostatic electrode, to prevent electric discharges by creating a path that shuts off discharge paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the placement surface has an unevenness structure, then the suction holding capability is improved, but the distance between the bottom surface of the concave portion and the electrostatic electrode becomes short, causing electric discharge to occur easily
Solution Approach 1:
The base body is divided into two regions with different resistance characteristics: a low-resistance region for effective suction holding and a high-resistance region for preventing electric discharge. This local differentiation allows each region to perform its specific function optimally without interfering with the other.
Solution Approach 2:
The high-resistance region acts as an intermediary barrier between the electrostatic electrode and the concave portion of the unevenness structure. It mediates the electrical field distribution, preventing direct electric discharge while allowing the suction holding function to operate through the low-resistance region.
2Reliability
If the ceramics have low resistance, then the suction holding efficiency is improved, but electric discharge occurs more easily in areas with low ceramic density and voids
Solution Approach 1:
Different regions of the base body are assigned different resistance properties: the low-resistance region provides efficient suction holding, while the high-resistance region compensates for areas with low ceramic density and voids by preventing electric discharge pathways through those defective areas.
Solution Approach 2:
The base body is constructed as a composite structure combining ceramics with different resistance characteristics. This composite approach allows the system to benefit from both low-resistance ceramics for suction efficiency and high-resistance ceramics for discharge prevention, effectively addressing both requirements simultaneously.
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 configuration effectively suppresses electric discharges near the groove area, ensuring reliable operation of the electrostatic chuck even in areas with low ceramic density and voids, enhancing the chuck's performance and preventing electrical failures.
Implementation Method 1
A low-resistance region made of ceramics and a high-resistance region made of ceramics having a volume resistivity higher than the low-resistance region are sequentially arranged from a side close to the groove between a bottom surface of the groove and the electrode
Data Source
AI summary
An electrostatic chuck includes a base body having a placement surface on which a suction target object is placed, and an electrode embedded in the base body. The base body is provided with a groove that opens to the placement surface-side and does not reach the electrode. Aloes-resistance region made of ceramics and a high-resistance region made of ceramics having a volume resistivity higher than the low-resistance region are sequentially arranged from a side close to the groove between a bottom surface of the groove and the electrode, in a thickness direction of the base body.