Electrostatic Chuck Asymmetric Electrode Roughness
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Solution Overview
Problem
Conventional electrostatic chucks face limitations in plasma controllability and in-plane uniformity of plasma density, particularly due to heat generation from high-frequency power supply-connected electrode layers within ceramic dielectric substrates, which affects RF responsiveness and plasma distribution.
Innovation Solution
An electrostatic chuck design featuring a ceramic dielectric substrate with a first electrode layer connected to a high-frequency power supply, where the surface roughness of one surface is greater than the other, and the distance between these surfaces is varied to enhance heat dissipation and plasma uniformity, utilizing materials like Ag, Pd, or Pt, and forming the electrode layer as a cermet to improve adhesion and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the power of the high frequency power supply applied to the electrode layer is increased to increase the plasma density, then the plasma density is improved, but the in-plane uniformity of the plasma density deteriorates due to heat generation from the electrode layer
Solution Approach 1:
The electrode layer is designed with different surface roughness values at different surfaces (first surface facing the substrate, second surface facing the dielectric layer), creating local quality differences that optimize both plasma generation and heat dissipation in their respective locations
Solution Approach 2:
The surface roughness parameter of the electrode layer is specifically controlled, with the first surface having a roughness of 0.1-10 μm and the second surface having a roughness of 0.1-20 μm. This parameter optimization enables effective heat dissipation from the second surface while maintaining proper plasma interaction at the first surface, allowing high plasma density with improved uniformity
2Adaptability or versatility
If a lower electrode for plasma generation is provided built into a dielectric layer, then the plasma controllability is improved, but the in-plane uniformity of the plasma density cannot be obtained sufficiently
Solution Approach 1:
The electrode layer embedded in the dielectric layer is given asymmetric surface roughness characteristics - the first surface (exposed to plasma) has optimized roughness for plasma interaction while the second surface (contacting dielectric) has roughness optimized for heat dissipation. This local quality differentiation enables the electrode to simultaneously achieve good plasma controllability and uniform plasma density distribution
Solution Approach 2:
The heat generation from the electrode layer, which was previously a harmful effect causing non-uniform plasma density, is converted into a beneficial effect by designing the second surface with appropriate roughness to enhance heat dissipation into the dielectric layer, thereby improving overall plasma uniformity
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 increases the in-plane uniformity of plasma density and RF responsiveness by optimizing the surface roughness and distance configurations, allowing for more effective heat dissipation and improved plasma generation with reduced electrical power consumption.
Implementation Method 1
plasma is generated by applying a voltage from an RF (Radio Frequency) power supply (a high frequency power supply) to an upper electrode provided at an upper portion inside a chamber and to a lower electrode provided lower than the upper electrode
Implementation Method 2
the environment inside the chamber changes particularly due to the heat generation of the electrode layer
Implementation Method 3
The electrostatic chuck applies electrical power for electrostatic attraction to a built-in electrode and attracts and holds a substrate such as a silicon wafer, etc., 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 first electrode layer. The ceramic dielectric substrate has a first major surface and a second major surface. The first electrode layer is provided inside the ceramic dielectric substrate and connected to a high frequency power supply. The first electrode layer is provided between the first major surface and the second major surface. The first electrode layer has a first surface and a second surface. A surface roughness of the second surface is larger than a surface roughness of the first surface.