Shower Head Assembly for Selective Wafer Bevel Deposition
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Solution Overview
Problem
Conventional bevel deposition methods in semiconductor manufacturing result in unintended central and backside deposition, leading to contamination, process interference, and non-uniform film application, which compromises device fabrication and reliability.
Innovation Solution
A process chamber with a substrate support assembly and a shower head assembly featuring concentric inner and outer regions of different thicknesses, combined with separate flow paths for process and purge gases, to selectively apply coatings only on the outer perimeter of the substrate while inhibiting deposition on the inner region, using RF biasing and controlled plasma formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bevel deposition methods are used, then coating can be applied to the substrate, but unintended central and backside deposition occurs causing contamination and non-uniform film application
Solution Approach 1:
The gas distribution plate is segmented into multiple regions (central region, intermediate region, and outer region) with different thicknesses, allowing each region to control deposition independently. The central region has greater thickness to prevent deposition on the substrate center, while the outer region has lesser thickness to enable bevel deposition at the perimeter
Solution Approach 2:
Different regions of the gas distribution plate are designed with different local properties (thickness variations) to achieve different deposition outcomes in corresponding substrate areas. The intermediate region serves as a transition zone with specific thickness to control the deposition gradient from center to edge
2Manufacturing precision
If conventional shower head design is used, then gas distribution is simple, but cannot achieve selective deposition on outer perimeter only
Solution Approach 1:
The design transitions from a conventional two-dimensional gas distribution plate to a three-dimensional structure with varying thickness across different regions. This dimensional addition allows selective deposition control by creating distance variations between the gas distribution plate and substrate at different radial positions
3Manufacturing precision
If uniform gas distribution plate thickness is used, then manufacturing is simple, but deposition is non-uniform across substrate regions
Solution Approach 1:
The gas distribution plate incorporates local quality variations through different thickness regions (central, intermediate, and outer regions) to achieve uniform deposition control across different substrate areas, with each region optimized for its specific deposition requirements
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
Enables concentric and uniform bevel deposition, preventing defects from propagating and enhancing substrate integrity, yield, and reliability by minimizing contamination and process interference.
Implementation Method 1
flowing a process gas through a first flow path of a shower head assembly of a chemical vapor deposition chamber to perform chemical vapor deposition of a coating on an outer region of a substrate
Implementation Method 2
flowing a purge gas through a second flow path of the shower head assembly to prevent deposition of the coating on an inner region of the substrate
Data Source
AI summary
A system includes a process chamber, a substrate support assembly to support a substrate, and a shower head assembly. The shower head assembly includes a gas distribution plate including an inner region having a first radius and a first thickness and an outer region, that is concentric with the inner region, having a f second radius that is greater than the first radius. The outer region further having a second thickness that is less than the first thickness causing the inner region to have a first distance from the substrate and the outer region to have a second distance from the substrate. The first distance is less than the second distance. The gas distribution plate is configured to deposit a coating on an outer region of the substrate without depositing the coating on an inner region of the substrate.