CVD Apparatus Wafer Stacking and Gas Distribution
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Solution Overview
Problem
Current chemical vapor deposition processes face limitations in mass production due to the structure of the susceptor, which restricts the number of wafers that can be processed simultaneously, and large-diameter wafers suffer from thermal stress-induced bowing and cracking issues during nitride semiconductor epitaxial thin film growth.
Innovation Solution
A chemical vapor deposition apparatus with a reaction chamber and wafer holder design that allows for the stacking and simultaneous processing of hundreds of wafers, featuring a gas supply unit with spray nozzles and a guide unit to evenly distribute reaction gases on both surfaces of the wafers, reducing thermal stress and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional susceptor structure is used to support sapphire wafers, then the chemical vapor deposition process can be performed, but the number of wafers that can be processed simultaneously is limited, restricting mass production capability
Solution Approach 1:
The susceptor is divided into multiple independent support positions arranged vertically, allowing hundreds of wafers to be stacked and processed simultaneously. Each support position can independently hold wafers, transforming a single-point support system into a multi-level parallel processing platform that dramatically increases throughput.
Solution Approach 2:
The patent transitions from a conventional single-plane wafer support to a three-dimensional stacked configuration. Wafers are arranged vertically at different heights along the susceptor, utilizing the vertical dimension to multiply processing capacity without increasing the horizontal footprint of the reaction chamber.
2Productivity
If large-diameter wafers are used to increase production capacity, then more chips can be produced per wafer, but thermal stress causes wafer bowing and cracking during nitride semiconductor growth
Solution Approach 1:
The patent employs susceptor design with multiple support points that distribute the wafer's weight and thermal stress evenly across the entire wafer surface. This counteracts the thermal gradients and mechanical stresses that would otherwise cause bowing and cracking in large-diameter wafers during high-temperature nitride semiconductor growth.
Solution Approach 2:
The susceptor provides localized support at multiple discrete positions across the wafer surface rather than uniform support. Each support point is strategically positioned to address specific stress concentration areas, allowing the system to handle larger wafer diameters without compromising structural integrity during the deposition process.
3Ease of operation
If reaction gas is supplied uniformly to all wafers, then processing simplicity is maintained, but non-uniform gas distribution reduces film quality and deposition uniformity
Solution Approach 1:
The gas supply system incorporates localized delivery mechanisms that provide tailored gas flow to different wafer positions. Spray nozzles are positioned to target specific wafer regions, and gas flow rates can be independently controlled for each wafer or wafer group, ensuring uniform film deposition across all wafers despite their varied positions in the reaction chamber.
Solution Approach 2:
The patent introduces intermediate gas distribution components such as spray nozzles and flow distributors that mediate between the main gas supply and individual wafers. These intermediaries actively regulate and distribute reaction gases, metal organic compounds, and carrier gases to ensure each wafer receives the precise gas composition and flow rate needed for uniform epitaxial film growth.
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 mass production of high-quality semiconductor epitaxial thin films on both surfaces of wafers, alleviating thermal stress and preventing bowing effects, thus improving productivity and wafer quality, especially for large-diameter wafers.
Implementation Method 1
a chemical vapor deposition apparatus including: a reaction chamber including an inner tube having a predetermined volume of an inner space, and an outer tube tightly sealing the inner tube; a wafer holder disposed within the inner tube and on which a plurality of wafers are stacked at predetermined intervals; and a gas supply unit including at least one gas line supplying an external reaction gas to the reaction chamber, and a plurality of spray nozzles communicating with the gas line to spray the reaction gas to the wafers, whereby semiconductor epitaxial thin films are grown on the surfaces of the wafers
Data Source
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AI summary
A chemical vapor deposition apparatus includes: a reaction chamber including an inner tube having a predetermined volume of an inner space, and an outer tube tightly sealing the inner tube; a wafer holder disposed within the inner tube and on which a plurality of wafers are stacked at predetermined intervals; and a gas supply unit including at least one gas line supplying an external reaction gas to the reaction chamber, and a plurality of spray nozzles communicating with the gas line to spray the reaction gas to the wafers, whereby semiconductor epitaxial thin films are grown on the surfaces of the wafers, wherein the semiconductor epitaxial thin film grown on the surface of the wafer includes a light emitting structure in which a first-conductivity-type semiconductor layer, an active layer, and a second-conductivity-type semiconductor layer are sequentially formed.