Roughened Substrate Support for PECVD Uniformity
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Solution Overview
Problem
Plasma enhanced chemical vapor deposition (PECVD) processes often result in local variations in film thickness due to glass thickness and flatness issues, leading to non-uniform plasma conditions and deposition variations.
Innovation Solution
A substrate support with a roughened surface, achieved through a two-step bead blasting process followed by anodization, to reduce arcing and promote uniform deposition by minimizing local capacitance variations and allowing free gas evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth substrate support surface is used, then the substrate support is easy to manufacture, but local capacitance variation occurs leading to non-uniform plasma and deposition variations
Solution Approach 1:
The substrate support surface roughness is changed from smooth to a specific roughness range (707-837 micro-inches) to eliminate local capacitance variation and achieve uniform plasma distribution, thereby resolving the contradiction between ease of manufacture and film thickness uniformity
2Reliability
If a roughened substrate support surface is used, then arcing is reduced and deposition uniformity is improved, but the manufacturing process complexity increases
Solution Approach 1:
The surface roughness parameter is precisely controlled to a specific range (707-837 micro-inches) which reduces arcing and improves deposition uniformity while managing process complexity through defined manufacturing parameters
Solution Approach 2:
The mechanical bead blasting process is replaced by an anodization chemical process to achieve the desired surface roughness, reducing manufacturing complexity while maintaining the reliability benefits of a roughened surface
3Shape
If bead blasting is used to roughen the surface, then surface roughness is achieved, but the substrate support surface may become too rough causing scratching
Solution Approach 1:
The surface roughness parameter is precisely controlled to a specific range (707-837 micro-inches) that provides sufficient roughness to reduce arcing while avoiding excessive roughness that would cause substrate scratching during deposition
Solution Approach 2:
The mechanical bead blasting process is replaced by anodization to achieve surface roughness, eliminating the risk of mechanical scratching while maintaining the desired surface characteristics for reducing arcing and improving deposition uniformity
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 roughened substrate support reduces arcing and deposition variations, ensuring a uniformly thick film layer is deposited on the substrate without scratching, while maintaining a surface roughness of between 707 micro-inches and 837 micro-inches.
Implementation Method 1
The roughened substrate support body may be formed by a bead blasting process
Implementation Method 2
The substrate support may have an anodized coating on the substrate support
Implementation Method 3
The precursor gas in the chamber is energized (e.g., excited) into a plasma by applying RF power to the chamber
Data Source
AI summary
The present disclosure generally relates to a substrate support for use in a substrate processing chamber. A roughened substrate support reduces arcing within the chamber and also contributes to uniform deposition on the substrate. A substrate support may have a substrate support body having a surface roughness of between about 707 micro-inches and about 834 micro-inches. The substrate support may have an anodized coating on the substrate support.