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, especially when using a base plate as the lower electrode for plasma generation, and face challenges in responsiveness to RF output modifications.
Innovation Solution
An electrostatic chuck design featuring a ceramic dielectric substrate with a first electrode layer connected to a high-frequency power supply and a second electrode layer connected to a chucking power supply, where the first electrode layer is positioned between the substrate's surfaces and has a varying thickness along its length to enhance plasma density and RF responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a base plate is used as the lower electrode for plasma generation, 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 patterns (first electrode patterns and second electrode patterns) formed on the inner surface of the dielectric layer. This segmentation allows independent control of different plasma regions, improving plasma controllability while maintaining structural simplicity through planar integration.
Solution Approach 2:
Different electrode patterns are designed with different characteristics (first electrode patterns for central region, second electrode patterns for peripheral region) to create local quality variations. This enables optimized plasma density distribution across different areas of the substrate, achieving in-plane uniformity through localized electrode design rather than uniform structure.
2Reliability
If a lower electrode is built into the dielectric layer, then plasma controllability is improved, but the in-plane uniformity of plasma density is not obtained sufficiently
Solution Approach 1:
The electrode patterns exhibit asymmetric design where the first electrode patterns in the central region have different configurations compared to the second electrode patterns in the peripheral region. This asymmetric arrangement compensates for the natural plasma density gradient, achieving uniform plasma distribution across the substrate surface.
Solution Approach 2:
The electrode patterns are designed with varying shapes, sizes, and spatial arrangements in different regions of the dielectric layer inner surface. This two-dimensional variation in electrode geometry allows precise control of plasma density distribution, achieving in-plane uniformity through dimensional design rather than simple thickness variation.
3Quantity of substance
If the RF output is modified to increase plasma density, then the plasma density increases, but the heat generation increases and RF responsiveness decreases
Solution Approach 1:
The lower electrode is divided into multiple segmented patterns rather than a single continuous electrode. This segmentation reduces the total surface area of the lower electrode, thereby reducing heat generation while maintaining effective plasma density control through distributed electrode patterns that cover necessary regions.
Solution Approach 2:
The electrode patterns are designed with optimized parameters including reduced surface area, adjusted pattern density, and modified geometric characteristics. These parameter changes enable effective plasma generation with lower RF power input, improving RF responsiveness while controlling heat generation through reduced electrode surface 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
The design increases plasma density and in-plane uniformity while reducing the electrical power required for plasma generation and improves heat dissipation, leading to enhanced RF responsiveness and uniformity.
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 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
Implementation Method 3
improves heat dissipation, leading to enhanced RF responsiveness and uniformity
Data Source
AI summary
According to one embodiment, an electrostatic chuck includes a ceramic dielectric, a base plate, a first electrode layer, and a second electrode layer. The ceramic dielectric substrate has a first major surface and a second major surface. The first electrode layer is provided between the first major surface and the second major surface. The second electrode layer is provided between the first electrode layer and the first major surface. The first electrode layer has a first surface and a second surface. A distance between the first surface and the first major surface is constant. A distance between the second surface and the first surface at an end portion of the first electrode layer is shorter than a distance between the second surface and the first surface at a central portion of the first electrode layer.