Layered Ceramic Electrostatic Chuck for Insulation and Wafer Holding
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Solution Overview
Problem
Existing electrostatic chucks for semiconductor wafers face challenges in achieving sufficient electrostatic attraction force due to the high insulation performance but low dielectric constant of alumina sintered ceramic dielectric layers.
Innovation Solution
The electrostatic chuck design includes a ceramic base, a thinner ceramic dielectric layer with a higher dielectric constant, and a thinner ceramic insulating layer with higher volume resistivity and withstand voltage, where the insulating layer is preferably an aerosol deposition film, and the dielectric layer is made of barium titanate or lead zirconate titanate, while the insulating layer is made of alumina, enhancing both insulation and electrostatic attraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumina sintered body is used as ceramic dielectric layer, then insulation performance is high, but electrostatic attraction force is insufficient
Solution Approach 1:
The ceramic layer is divided into two distinct layers: a ceramic dielectric layer (alumina sintered body) for insulation and a ceramic insulating layer (barium titanate or lead zirconate titanate) for electrostatic attraction. This segmentation allows each layer to optimize its specific function, resolving the contradiction between insulation performance and electrostatic force.
Solution Approach 2:
The patent uses a composite structure combining alumina sintered body with high-dielectric-constant ceramic materials. The ceramic dielectric layer provides insulation while the ceramic insulating layer enhances electrostatic attraction, creating a composite system that achieves both high insulation performance and high electrostatic force.
2Force
If ceramic dielectric layer is made thinner to increase electrostatic force, then electrostatic attraction force increases, but insulation performance decreases
Solution Approach 1:
By segmenting the ceramic structure into two layers with different thicknesses and material properties, the system can have a thin ceramic insulating layer for high electrostatic force while maintaining adequate insulation through the combined structure. The ceramic dielectric layer compensates for the reduced thickness of the insulating layer.
Solution Approach 2:
The patent changes material parameters by selecting ceramics with different dielectric constants and resistivity characteristics for each layer. The ceramic insulating layer uses materials with higher dielectric constants to maintain force despite reduced thickness, while the ceramic dielectric layer provides the necessary insulation performance.
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 provides high insulation performance and increased electrostatic attraction force, ensuring effective wafer holding during semiconductor processes like CVD and micromachining.
Implementation Method 1
an electrostatic electrode embedded between the ceramic dielectric layer and the ceramic base
Implementation Method 2
the ceramic insulating layer has a higher volume resistivity and withstand voltage than the ceramic dielectric layer
Data Source
AI summary
An electrostatic chuck includes a ceramic base, a ceramic dielectric layer, an electrostatic electrode, and a ceramic insulating layer. The ceramic dielectric layer is positioned on the ceramic base and is thinner than the ceramic base. The electrostatic electrode is embedded between the ceramic dielectric layer and the ceramic base. The ceramic insulating layer is positioned on the ceramic dielectric layer and is thinner than the ceramic dielectric layer. The ceramic insulating layer has a higher volume resistivity and withstand voltage than the ceramic dielectric layer, and the ceramic dielectric layer has a higher dielectric constant than the ceramic insulating layer.