Showerhead Electrode Cam Locks and Gas Hole Pattern
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Solution Overview
Problem
In plasma processing chambers, the warping of monolithic/inner electrodes and differential thermal expansion between these electrodes and backing plates can lead to rubbing, resulting in particulate contaminants and non-uniform processing rates, which degrade device yield in semiconductor substrate fabrication.
Innovation Solution
A showerhead electrode assembly with a plurality of cam locks that securely attach the inner electrode to the backing plate at multiple positions, reducing warping and thermal non-uniformity, and a specific gas injection hole pattern for uniform gas distribution, minimizing particle generation and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a monolithic/inner electrode is used in a plasma processing chamber, then the processing efficiency is improved, but warping and differential thermal expansion occur leading to rubbing and particulate contaminants
Solution Approach 1:
The electrode assembly is segmented into multiple components: an inner electrode, an outer electrode, and a backing plate. This segmentation allows each component to be optimized independently and reduces thermal stress concentration, preventing warping while maintaining processing efficiency.
Solution Approach 2:
The electrode assembly uses composite construction with different materials for the inner electrode, outer electrode, and backing plate. This composite structure accommodates differential thermal expansion between materials, reducing warping and rubbing while maintaining the high processing efficiency of the monolithic design.
2Object-generated harmful factors
If gas injection holes are made smaller to reduce particle generation, then contamination is minimized, but gas distribution uniformity becomes more difficult to achieve
Solution Approach 1:
The gas distribution system employs local quality optimization by varying the hole diameter within specific zones while maintaining a consistent concentric pattern. This allows smaller holes (≤0.04 inch) to be used throughout the pattern, reducing particle generation, while the systematic arrangement ensures uniform gas distribution across the substrate surface.
Solution Approach 2:
The gas injection system uses parameter changes by implementing a specific hole diameter threshold (≤0.04 inch) and a systematic concentric arrangement with varying radial distances. This parameter optimization reduces particle generation while maintaining uniform gas distribution through the structured pattern design.
3Manufacturing precision
If multiple gas injection holes are arranged in concentric rows, then gas distribution uniformity is improved, but the complexity of the electrode structure increases
Solution Approach 1:
The gas injection pattern uses asymmetric hole distribution within a symmetric concentric framework. Each row contains a specific number of holes (7, 17, 28, 40, 48, 56, 64, 72) positioned at calculated radial distances, creating an asymmetric yet systematic pattern that achieves uniform gas distribution while managing structural complexity.
Solution Approach 2:
The gas injection system transitions from a two-dimensional surface pattern to a three-dimensional concentric arrangement with varying radial distances from the center. This dimensional approach (with radial distances ranging from 0.6-0.7 inch to 5.7-5.8 inches) enables uniform gas distribution across the substrate while organizing complexity in a systematic spatial framework.
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 solution effectively reduces warping of the inner electrode, maintains processing rate uniformity, and minimizes particulate contaminants, thereby enhancing the yield and quality of semiconductor substrates during plasma etching and deposition processes.
Implementation Method 1
A showerhead electrode assembly with a plurality of cam locks that securely attach the inner electrode to the backing plate at multiple positions
Implementation Method 2
a specific gas injection hole pattern for uniform gas distribution
Implementation Method 3
supplying an etching or deposition gas to the vacuum chamber and application of a radio frequency (RF) field to the gas to energize the gas into a plasma state
Data Source
AI summary
A showerhead electrode, a gasket set and an assembly thereof in plasma reaction chamber for etching semiconductor substrates are provided with improved a gas injection hole pattern, positioning accuracy and reduced warping, which leads to enhanced uniformity of plasma processing rate. A method of assembling the inner electrode and gasket set to a supporting member includes simultaneous engagement of cam locks.