Plasma Chuck Bias Layout for Uniform Edge-to-Center Etching
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Solution Overview
Problem
Plasma processing apparatuses face challenges in maintaining uniform etching rates across substrates due to variations in plasma sheath thickness and electrode thickness, leading to tilted etching holes and global tilting issues, which result in uneven etching rates.
Innovation Solution
The apparatus incorporates a substrate support with a first region for the substrate and a second region for the edge ring, featuring first and second bias electrodes and impedance adjusting mechanisms connected via an electrical path, allowing independent control of potential differences to adjust the etching rate uniformly across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the plasma sheath thickness is reduced to improve etching uniformity, then the etching rate uniformity improves, but the plasma sheath becomes too thin to effectively control the electric field distribution
Solution Approach 1:
The patent introduces an edge ring as an intermediary component between the substrate and the chamber wall. The edge ring includes a bias electrode that can independently control the electric field distribution at the substrate edge, acting as a mediator to adjust plasma sheath characteristics without directly changing the overall plasma sheath thickness. This allows independent control of electric field distribution while maintaining adequate plasma sheath thickness for stable plasma generation.
Solution Approach 2:
The patent changes the electrical parameters by introducing a bias power supply connected to the edge ring's bias electrode. By independently adjusting the bias voltage applied to the edge ring, the system can control the potential difference between the substrate center and edge, thereby controlling plasma sheath thickness locally at the edge region without affecting the overall plasma sheath thickness. This parameter change enables precise control of electric field distribution and plasma sheath characteristics.
2Device complexity
If the substrate support structure is simplified to reduce device complexity, then the manufacturing cost decreases, but the ability to independently control potential differences between substrate and edge ring is reduced
Solution Approach 1:
The patent segments the substrate support structure into functionally independent regions: a central substrate support region and a surrounding edge ring region. Each region has its own bias electrode (first bias electrode for the substrate, second bias electrode for the edge ring) that can be controlled independently. This segmentation allows independent control of potential differences in different regions while maintaining a relatively simple overall structure. The electrical path is also segmented into separate control circuits for each bias electrode.
Solution Approach 2:
The edge ring structure serves multiple functions: it provides mechanical support for the substrate, acts as a separate electrical control element with its own bias electrode, and functions as a plasma generation region. This multi-functionality allows the system to control potential differences independently without adding significant structural complexity. The same edge ring component performs both mechanical and electrical control functions.
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 effectively suppresses unevenness in etching rates by controlling the potential differences between the substrate and edge ring, ensuring consistent etching performance across the substrate.
Implementation Method 1
controlling the potential differences between the substrate and edge ring
Implementation Method 2
plasma sheath thickness
Implementation Method 3
impedance adjusting mechanisms connected via an electrical path, allowing independent control of potential differences
Data Source
AI summary
A plasma processing apparatus includes a chamber, a bias power supply, a substrate support configured to support a substrate and an edge ring in the chamber, a plurality of first impedance adjusting mechanisms, and an electrical path. The substrate support includes a first region configured to support the substrate, a second region provided around the first region and configured to support the edge ring, a first bias electrode provided in the first region, a plurality of first impedance adjusting electrodes provided in the first region and grounded, and a second bias electrode provided in the second region. The plurality of first impedance adjusting mechanisms are configured to be respectively connected to the plurality of first impedance adjusting electrodes. The electrical path is configured to connect the bias power supply, the first bias electrode, and the second bias electrode.