Gas Diffusion Assembly with Split Flow Channels for Uniform Epitaxy
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Solution Overview
Problem
Existing substrate processing devices face challenges in achieving uniform gas distribution within the reaction chamber during epitaxial growth, leading to non-uniform film thickness on substrates due to interactions between middle and outer gas flows and the effects of wafer rotation.
Innovation Solution
A gas diffusion assembly with a guider featuring a narrow middle flow channel and wider outer flow channels, along with a gas intake device that includes a gas distributor and auxiliary gas intake, ensures uniform gas distribution by adjusting the intake pressure of the middle flow channel independently of the outer channels, and incorporates diffusion plates and a flow equalizing plate to enhance gas mixing and dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas is introduced through a single flow channel configuration, then the device structure is simple, but the gas distribution uniformity across the substrate is poor
Solution Approach 1:
The gas distribution system is segmented into multiple independent flow channels: a middle flow channel for the central substrate region and outer flow channels for the peripheral regions. This segmentation allows independent gas flow control to different areas, enabling uniform film thickness deposition across the entire substrate by addressing the specific needs of different regions.
Solution Approach 2:
Different flow channels are designed with different width ratios to provide locally optimized gas distribution. The middle flow channel has a specific width ratio (1:2 to 1:4) compared to outer flow channels, creating localized gas flow characteristics that match the requirements of different substrate regions for uniform epitaxial growth.
2Manufacturing precision
If the middle flow channel and outer flow channels have the same width ratio, then the structure is symmetric and simple, but the gas pressure distribution becomes non-uniform causing non-uniform film thickness
Solution Approach 1:
The flow channel design deliberately breaks symmetry by setting different width ratios for the middle flow channel versus the outer flow channels. The middle flow channel width ratio is specifically designed to be 1:2 to 1:4 compared to outer channels, creating asymmetric gas flow distribution that compensates for pressure variations and achieves uniform film thickness across the substrate.
3Productivity
If gas flow rates in all channels are increased to improve deposition speed, then productivity increases, but pressure variations increase causing non-uniform gas distribution
Solution Approach 1:
The system enables dynamic and independent adjustment of gas flow rates in different channels. By controlling the middle and outer flow channels separately, the system can optimize deposition speed while maintaining uniform gas distribution, allowing productivity improvement without sacrificing film thickness 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 solution achieves uniform gas distribution in the reaction chamber, improving the uniformity of the deposited film layer thickness by minimizing pressure variations across the substrate, even with wafer rotation.
Implementation Method 1
the guider includes a middle flow channel and outer flow channels... The outer flow channels and the middle flow channel extend in parallel along the length direction of the guider
Implementation Method 2
incorporates diffusion plates and a flow equalizing plate to enhance gas mixing and dispersion
Data Source
AI summary
A gas diffusion assembly including a guider. The first end of the guider in the length direction of the guider is used to connect with the gas distributor, and the second end of the guider in the length direction of the guider is used to connect with the reaction chamber. The guider includes a middle flow channel and outer flow channels, two of the outer flow channels respectively provided on opposite sides of the middle flow channel in the width direction of the middle flow channel. Both the outer flow channels and the middle flow channel extend in parallel along the length direction of the guider, and the width ratio of the outer flow channel to the middle flow channel is 40±10:20±20.