Variable Exhaust Pathways for Uniform Epitaxial Gas Deposition
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Solution Overview
Problem
Existing semiconductor processing chambers face challenges in achieving uniform deposition of process gases across substrates due to non-uniform gas flow rates and limited modularity in adjusting process parameters, leading to issues such as plume-shaped gas concentration profiles and center-to-edge uniformity.
Innovation Solution
The implementation of gas exhaust frames with varying cross-sectional areas and size gradients in semiconductor processing chambers, which include a first set of exhaust pathways increasing in one direction and a second set in the opposite direction, to facilitate modularity in adjusting gas flow rates, pressures, and temperatures for enhanced deposition uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform exhaust pathways are used throughout the chamber, then the structure is simple and easy to manufacture, but gas flow uniformity and deposition uniformity deteriorate due to non-uniform gas flow rates and plume-shaped concentration profiles
Solution Approach 1:
The exhaust pathways are designed with varying cross-sectional areas at different locations within the chamber. Specifically, the exhaust pathways have different sizes in different regions to create localized gas flow control, which corrects the non-uniform gas flow rates and eliminates plume-shaped concentration profiles, thereby achieving uniform deposition across the substrate.
Solution Approach 2:
The exhaust pathways are designed with asymmetric cross-sectional areas, where pathways in different regions of the chamber have different sizes. This asymmetric design creates non-uniform gas flow patterns that compensate for the plume-shaped concentration profiles, achieving overall gas flow uniformity and improved deposition uniformity across the substrate surface.
2Manufacturing precision
If exhaust pathway sizes are varied to improve gas flow control, then deposition uniformity improves, but manufacturing complexity and difficulty increase
Solution Approach 1:
The exhaust pathways are designed with specific parameter variations, including different cross-sectional areas, lengths, and positions at different locations within the chamber. These parameter changes are optimized to create the desired gas flow patterns that achieve uniform center-to-edge deposition, while the variations are designed to be manufacturable using standard fabrication techniques.
3Adaptability or versatility
If modular adjustment of process parameters is enabled, then adaptability improves, but device complexity increases
Solution Approach 1:
The exhaust system is segmented into multiple independent exhaust pathways with varying cross-sectional areas positioned at different locations within the chamber. Each exhaust pathway can be independently designed and optimized, allowing modular adjustment of process parameters such as gas flow rates and pressures to achieve different deposition patterns and uniformity requirements.
Data Source
AI summary
An embodiment of an epitaxial deposition chamber includes a chamber body and an upper window and a lower window positioned in the chamber body. In addition, the deposition chamber includes a substrate support positioned in the chamber body, between the upper window and the lower window, so that a processing volume is defined between the substrate support and the upper window. Further, the deposition chamber includes one or more heat sources configured to heat the processing volume and one or more gas inlets into the processing volume. Still further, the deposition chamber includes a plurality of exhaust pathways out of the processing volume. Each of the plurality of exhaust pathways has an adjustable cross-sectional area.