Ceramic Joined Body Structure for Electrostatic Chuck Insulation
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Solution Overview
Problem
The existing electrostatic chuck devices experience breakdown (discharge) at the joint interface between the composite dielectric ceramic and the internal electrode due to exposed conductive paths, leading to poor insulating characteristics.
Innovation Solution
A ceramic joined body is formed with a pair of ceramic plates and interposed conductive and insulating layers, where the porosity at the interface is 4% or less, and the ratio of average primary particle diameters is more than 1, using specific materials and manufacturing processes to suppress breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the joint surfaces of composite dielectric ceramic and internal electrode are joined after polishing, then the manufacturing process is simple, but the conductive material is exposed at the joint interface forming conductive paths that reduce insulating characteristics
Solution Approach 1:
The patent applies preliminary action by forming the insulating layer on the joint surfaces of both the composite dielectric ceramic and the internal electrode before joining them. This pre-coating with insulating material prevents conductive material exposure at the joint interface, eliminating the conductive paths that would otherwise form during polishing and joining operations. The insulating layer is applied in advance to ensure insulating characteristics are maintained throughout the manufacturing process.
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure at the joint interface consisting of the insulating layer and the conductive layer. This composite structure combines the insulating properties of the insulating material with the conductive properties of the electrode material, allowing the joint to simultaneously achieve good electrical insulation and adequate mechanical bonding. The composite layered structure resolves the contradiction between conductivity and insulation requirements at the joint interface.
2Strength
If the joint surfaces are polished to improve surface quality, then the joining strength is improved, but the conductive material becomes exposed at the joint interface
Solution Approach 1:
The insulating layer is applied to the joint surfaces before polishing and joining operations. This preliminary coating protects the conductive material from exposure during subsequent mechanical processing. The insulating layer remains intact through polishing, ensuring that even as the joint surfaces are refined for better bonding, the insulating characteristics are preserved and conductive material does not become exposed.
Solution Approach 2:
The insulating layer serves as a protective cushion applied beforehand to prevent the harmful effect of conductive material exposure. This layer acts as a barrier that cushions against the potential damage of exposing conductive material during polishing and joining, ensuring that the insulating properties are maintained even under the mechanical stresses of the manufacturing process.
3Ease of operation
If a conductive layer is formed on the ceramic plate to improve electrostatic chucking function, then the chucking performance is enhanced, but breakdown occurs at the joint interface due to exposed conductive paths
Solution Approach 1:
The patent segments the joint interface structure into distinct functional layers: an insulating layer and a conductive layer. The insulating layer is positioned at the joint interface to prevent breakdown, while the conductive layer is placed on the outer surface of the ceramic plate to provide electrostatic chucking function. This segmentation separates the conflicting requirements of conductivity for chucking performance and insulation for breakdown resistance, allowing both functions to coexist without interference.
Solution Approach 2:
The patent applies local quality by providing different material properties at different locations of the electrostatic chuck member. The joint interface region is given insulating characteristics through the insulating layer to prevent breakdown, while the outer surface region maintains conductive characteristics through the conductive layer for effective electrostatic chucking. This localized differentiation of material properties resolves the contradiction between chucking performance and breakdown resistance.
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 ceramic joined body effectively prevents breakdown at the joint interface, ensuring reliable operation of the electrostatic chucking device by maintaining insulating characteristics and durability.
Implementation Method 1
a porosity at an interface between the pair of ceramic plates and the insulating layer is 4% or less, and a ratio of an average primary particle diameter of an insulating material which forms the insulating layer to an average primary particle diameter of an insulating material which forms the ceramic plate is more than 1
Implementation Method 2
a plate-shaped sample such as a silicon wafer is fixed to an electrostatic chuck member having an electrostatic chuck function by electrostatic adsorption
Implementation Method 3
the coolant for adjusting a temperature is circulated for heat exchange to the flow path of the base member for adjusting a temperature
Implementation Method 4
a base member for adjusting a temperature where a flow path that circulates a coolant for controlling a temperature to the inside of a metal member is formed
Data Source
AI summary
A ceramic joined body (1) includes: a pair of ceramic plates (2,3) that include a conductive material; and a conductive layer (4) and an insulating layer (5) that are interposed between the pair of ceramic plates (2, 3), a porosity at an interface between the pair of ceramic plates (2, 3) and the insulating layer (5) is 4% or less, and a ratio of an average primary particle diameter of an insulating material which forms the insulating layer (5) to an average primary particle diameter of an insulating material which forms the ceramic plates (2, 3) is more than 1.