Electrostatic Chuck Electrode Segmentation for Plasma Uniformity
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Solution Overview
Problem
Conventional electrostatic chucks have limited plasma controllability and in-plane uniformity of plasma density due to the configuration of the lower electrode, which affects the efficiency of plasma processing in semiconductor and glass substrate handling.
Innovation Solution
The electrostatic chuck incorporates a ceramic dielectric substrate with a first electrode layer connected to a high-frequency power supply and a second electrode layer connected to a clamping power supply, featuring distinct portions with varying electrical resistance, surface roughness, and ceramic concentration to optimize plasma distribution and reduce skin effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a base plate is used as the lower electrode in a conventional electrostatic chuck, then the structure is simple, but the plasma controllability and in-plane uniformity of plasma density are limited
Solution Approach 1:
The lower electrode is segmented into multiple independent electrode layers (first electrode layer and second electrode layer) with different functions. The first electrode layer is connected to high-frequency power supply for plasma generation, while the second electrode layer is connected to clamping power supply for substrate holding. This segmentation enables independent control of plasma density distribution and substrate clamping, resolving the contradiction between plasma controllability and structural simplicity.
Solution Approach 2:
The first electrode layer is divided into a first portion and a second portion with different electrical resistance characteristics. The first portion has higher electrical resistance to concentrate plasma density in the central region, while the second portion has lower electrical resistance for uniform plasma distribution in peripheral regions. This local quality differentiation enables precise control of in-plane plasma density uniformity.
2Manufacturing precision
If a single electrode layer is provided inside the ceramic dielectric substrate, then the structure is simple, but the in-plane uniformity of plasma density cannot be obtained sufficiently
Solution Approach 1:
The single electrode layer is divided into multiple electrode layers (first electrode layer and second electrode layer) with distinct functions. The first electrode layer connects to high-frequency power supply for plasma generation, while the second electrode layer connects to clamping power supply. This segmentation enables independent optimization of plasma density uniformity and substrate clamping force distribution.
Solution Approach 2:
The first electrode layer is divided into a first portion and a second portion with different electrical resistance values. The first portion has higher electrical resistance to generate concentrated plasma in the central region, while the second portion has lower electrical resistance for uniform plasma distribution in peripheral regions. This local quality differentiation achieves sufficient in-plane uniformity of plasma density.
3Manufacturing precision
If the first surface of the first portion has low electrical resistance, then current flow is easy, but current concentration occurs reducing plasma uniformity
Solution Approach 1:
The first surface of the first portion is designed with higher electrical resistance compared to other regions. This local quality differentiation prevents current concentration at the first surface, ensuring stable and uniform current distribution throughout the electrode layer. The higher resistance at the first surface redistributes the current path, eliminating hot spots and achieving uniform plasma density across the substrate processing area.
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 enhances plasma controllability and in-plane uniformity of the plasma density, reducing the risk of current concentration and improving the overall efficiency of plasma processing.
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
an electrical resistance of the first surface is greater than an average electrical resistance of the first portion
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 first and second electrode layers. The ceramic dielectric substrate includes first and second major surfaces. The first and second electrode layers are provided inside the ceramic dielectric substrate. The second electrode layer is provided between the first electrode layer and the first major surface. The first electrode layer includes first and second portions. The first portion is positioned more centrally of the ceramic dielectric substrate than is the second portion. The first portion includes first and second surfaces. The second portion includes third and fourth surfaces. The third surface is positioned between the first surface and the second electrode layer. An electrical resistance of the first surface is greater than an average electrical resistance of the first portion.