Cryogenic Electrostatic Chuck Bonding Layer for Peel Resistance
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Solution Overview
Problem
Conventional electrostatic chucks face challenges in low-temperature environments, particularly at cryogenic temperatures below −60° C., where the flexibility of the bonding layer between the ceramic dielectric substrate and the base plate decreases, leading to risks of peeling or fracture.
Innovation Solution
An electrostatic chuck design incorporating a metal base plate and a resin-based bonding layer that meets specific conditions for elongation percentage, bonding strength, and elastic modulus at both room temperature and cryogenic temperatures, ensuring sufficient flexibility and bonding strength to prevent substrate breakage and peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional bonding layer is used in cryogenic environments (−60° C. or less), then the electrostatic chuck can operate at low temperatures, but the flexibility of the bonding layer decreases, causing the ceramic dielectric substrate to peel from the base plate or break
Solution Approach 1:
The patent changes the material parameters of the bonding layer by specifying elongation percentage, bonding strength, and elastic modulus at different temperatures. The bonding layer is designed to have elongation percentage of not less than 120% at −60° C. and specific bonding strength (0.4-10 MPa) and elastic modulus (0.1-10 MPa) to maintain flexibility in cryogenic environments while preventing substrate peeling or breakage
Solution Approach 2:
The patent uses a composite bonding layer made of resin material that combines multiple properties: high elongation percentage (≥120% at −60° C.), controlled bonding strength (0.4-10 MPa), and controlled elastic modulus (0.1-10 MPa). This composite material approach allows the bonding layer to simultaneously provide flexibility and bonding strength across a wide temperature range from −60° C. to 25° C.
2Strength
If the bonding layer is made rigid to maintain bonding strength at low temperatures, then peeling is prevented, but the ceramic dielectric substrate may break or fracture due to loss of flexibility
Solution Approach 1:
The patent precisely controls the bonding strength parameter of the bonding layer to be between 0.4 MPa and 10 MPa at −60° C., and elastic modulus between 0.1 MPa and 10 MPa. This parameter optimization ensures the bonding layer is strong enough to prevent peeling while remaining flexible enough to protect the ceramic dielectric substrate from breakage or fracture in cryogenic environments
3Strength
If the electrostatic chuck is designed for high bonding strength at room temperature (25° C.), then bonding is secure, but the bonding layer becomes too rigid for cryogenic environments (−60° C. or less)
Solution Approach 1:
The patent specifies that the bonding layer must maintain elongation percentage of not less than 120% at −60° C. and a ratio of elongation percentages (α1/α2) of not less than 0.6 between −60° C. and 25° C. This ensures the bonding layer retains sufficient flexibility across the temperature range while providing adequate bonding strength at both room temperature and cryogenic temperatures
Solution Approach 2:
The bonding layer is designed with dynamic mechanical properties that adapt to temperature changes. The material maintains appropriate flexibility and bonding strength characteristics across the temperature range from −60° C. to 25° C., with elongation percentage, bonding strength, and elastic modulus values that ensure proper function in both warm and cryogenic environments
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 solution enhances the electrostatic chuck's performance by maintaining flexibility and bonding strength across temperature variations, preventing substrate breakage and peeling, and ensuring reliable operation in cryogenic environments.
Implementation Method 1
An elastic modulus γ1 of the bonding layer at −60° C. is not less than 0.1 MPa and not more than 10 MPa; Sixth condition: A ratio γ1/γ2 of the elastic modulus γ1 to an elastic modulus γ2 of the bonding layer at 25° C. is not less than 0.6 and not more than 30
Implementation Method 2
The electrostatic chuck applies electrical power for electrostatic attraction to the built-in electrode and attracts and holds a substrate such as a silicon wafer or the like by an electrostatic force
Data Source
AI summary
According to one embodiment, an electrostatic chuck includes a ceramic dielectric substrate, a base plate, and a bonding layer provided between the ceramic dielectric substrate and the base plate. At least one of the following first to sixth conditions is satisfied: First condition: An elongation percentage α1 is not less than 120%; Second condition: A ratio α1/α2 of the elongation percentage is not less than 0.60; Third condition: A bonding strength β1 is not less than 0.4 MPa and not more than 10 MPa; Fourth condition: A ratio β1/β2 of the bonding strength is not less than 0.6 and not more than 10; Fifth condition: An elastic modulus γ1 is not less than 0.1 MPa and not more than 10 MPa; Sixth condition: A ratio γ1/γ2 of the elastic modulus is not less than 0.6 and not more than 30.