Shower Plate Multi-Plane Gas Flow Passages for MOCVD Uniformity
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Solution Overview
Problem
In vapor phase growth methods, particularly in MOCVD, achieving uniform mixing and distribution of source gases and separation gases to form high-quality, uniform semiconductor films on substrates is challenging due to issues with gas flow resistance and ejection hole arrangement, leading to variations in film thickness and quality.
Innovation Solution
The vapor phase growth apparatus features a shower plate with a hierarchical structure of lateral and longitudinal gas flow passages, optimizing the arrangement and inner diameters of gas ejection holes to reduce fluid resistance and enhance uniform gas flow distribution, allowing for increased density of gas ejection holes while maintaining uniformity of film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas ejection holes are arranged densely on the shower plate to improve film uniformity, then manufacturing precision improves, but fluid resistance increases causing flow non-uniformity
Solution Approach 1:
The shower plate is segmented into multiple independent gas flow passages, each with its own ejection holes. This segmentation allows each passage to have optimized hole spacing and dimensions, reducing overall fluid resistance while maintaining dense coverage. The gas flow is divided into multiple channels, preventing excessive resistance accumulation.
Solution Approach 2:
Gas ejection holes are arranged in a three-dimensional configuration across multiple horizontal planes rather than a single plane. This dimensional distribution reduces the density of holes in any single plane, decreasing local fluid resistance while still achieving uniform coverage across the entire substrate surface through vertical distribution.
2Manufacturing precision
If inner diameter of gas flow passages is reduced to increase hole density, then manufacturing precision improves, but fluid resistance increases leading to flow non-uniformity
Solution Approach 1:
The gas flow system is segmented into multiple passages with different inner diameters optimized for their specific functions. Larger passages handle high-flow regions, while smaller passages serve areas requiring precise flow control. This segmentation allows each passage to operate within optimal flow parameters, maintaining uniformity without excessive complexity.
Solution Approach 2:
Different regions of the shower plate have gas flow passages with locally optimized inner diameters and hole configurations. Areas requiring higher flow rates have larger passages, while areas needing precise distribution have smaller, more numerous passages. This local optimization achieves uniform film formation without requiring uniform complex design throughout.
3Manufacturing precision
If multiple source gases are mixed uniformly to form high-quality films, then manufacturing precision improves, but gas flow control difficulty increases
Solution Approach 1:
Different source gases are supplied through separate, segmented gas flow passages rather than a single mixed system. This segmentation allows independent control of each gas flow rate and timing, simplifying the mixing process. Each passage can be controlled separately to achieve the desired stoichiometry and film quality without complex simultaneous mixing control.
Solution Approach 2:
Gas mixing and flow regulation is performed preliminarily within each segmented passage before the gases reach the ejection holes. Flow rates and compositions are pre-adjusted in separate channels, then combined in a controlled manner. This preliminary preparation simplifies the overall control system by handling mixing upstream rather than requiring complex real-time mixing control at the ejection point.
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
This configuration results in improved uniformity of film thickness and quality by stabilizing the flow of process gases, enabling the growth of high-quality semiconductor films, such as GaN, with enhanced uniformity and reduced turbulence near the gas ejection holes.
Implementation Method 1
the shower plate configured to supply gas into the reaction chamber
Implementation Method 2
A vapor phase growth apparatus in one aspect of the present disclosure includes: a reaction chamber; a shower plate disposed in an upper portion of the reaction chamber
Implementation Method 3
While the wafer is heated, a process gas such as a source gas which is a raw material used in the film-formation is supplied
Data Source
AI summary
A vapor phase growth apparatus in an embodiment includes: a shower plate in an upper portion of the reaction chamber, the shower plate having first lateral gas flow passages in a first horizontal plane, first longitudinal gas flow passages being connected to the first lateral gas flow passages, the first longitudinal gas flow passages extending in a longitudinal direction, each of the first longitudinal gas flow passages having a first gas ejection hole, the shower plate having second lateral gas flow passages in a second horizontal plane upper than the first horizontal plane, second longitudinal gas flow passages being connected to the second lateral gas flow passages, the second longitudinal gas flow passages extending in the longitudinal direction through between the first lateral gas flow passages, each of the second longitudinal gas flow passages having a second gas ejection hole, and a support unit provided below the shower plate.