Electrostatic Chuck Segmented Electrode 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 performance during plasma processing.
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 metal/ceramic concentrations to optimize the distribution of high-frequency current and plasma density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base plate is used as the lower electrode for plasma generation, then the electrostatic chuck can hold the substrate, 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 patterns (first electrode pattern, second electrode pattern, third electrode pattern) with different geometries and positions. Each pattern can be controlled independently to achieve precise plasma density distribution across the substrate surface, resolving the contradiction between plasma controllability and structural complexity by breaking down a single complex electrode into multiple simpler可控 elements.
Solution Approach 2:
Different regions of the lower electrode are designed with different electrical characteristics (conductive regions with varying resistance values) to create localized plasma density control. The first, second, and third electrode patterns have different resistance values and geometries, allowing each region to generate plasma with specific local characteristics, thereby achieving overall in-plane uniformity through localized optimization.
2Reliability
If a single lower electrode is provided in the base plate, then the structure is simple, but the in-plane uniformity of plasma density cannot be obtained sufficiently
Solution Approach 1:
The lower electrode is divided into multiple segmented electrode patterns (first, second, and third electrode patterns) with different resistance values and geometries. This segmentation allows independent control of plasma generation in different regions, achieving uniform plasma density distribution across the substrate while maintaining reasonable structural complexity through modular design.
Solution Approach 2:
The electrode patterns are designed with different resistance values (first electrode pattern has higher resistance than second and third patterns) and different geometric parameters. By changing these electrical and geometric parameters across different electrode regions, the plasma density can be optimized for uniformity across the substrate surface.
3Power
If high power is applied to generate high plasma density, then plasma processing performance improves, but dielectric breakdown risk increases
Solution Approach 1:
The lower electrode is segmented into multiple electrode patterns with different resistance values, allowing the total power to be distributed across multiple regions rather than concentrated in a single electrode. This segmentation enables high overall plasma density while preventing localized overheating and dielectric breakdown by spreading the thermal and electrical stress across multiple controlled regions.
Solution Approach 2:
Different electrode patterns are designed with different resistance characteristics to distribute power application locally. Regions with higher resistance can handle higher power density, while regions with lower resistance provide cooling and stress distribution, creating a balanced power distribution that achieves high plasma density without causing dielectric breakdown.
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 achieves improved in-plane uniformity of plasma density, reducing the electrical power required for high plasma density and preventing dielectric breakdown.
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
plasma is generated by applying a voltage from an RF (Radio Frequency) power supply
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 less than an average electrical resistance of the first portion.