Susceptor Support Arm Width Optimization for Epitaxial Uniformity
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Solution Overview
Problem
The uniformity of the epitaxial film thickness on semiconductor wafers is compromised due to temperature non-uniformity caused by the susceptor support portion, which is exacerbated by the deformation of the susceptor under high-temperature conditions and the shadowing effect of its arms.
Innovation Solution
A susceptor support portion with a susceptor shaft and substrate lift portion featuring radially extending arms, including a through hole in the second arm, and a lift pin configuration that allows for vertical motion and rotation, reduces heating influence while maintaining sufficient support, using a cap on the support column and a concave portion on the pedestal to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the number of arms of the susceptor support portion is increased to four or more to strengthen support force and prevent susceptor deformation, then the susceptor deformation is reduced, but the area shadowed by the susceptor support portion increases, leading to temperature non-uniformity
Solution Approach 1:
The patent changes the geometric parameters of the arms, specifically making the width of the first arm smaller than the width of the second arm. This parameter optimization reduces the shadowed area while maintaining sufficient structural support, resolving the contradiction between preventing susceptor deformation and maintaining temperature uniformity.
2Temperature
If the width of the arms is reduced to decrease shadowed area, then the temperature uniformity is improved, but the support strength is reduced
Solution Approach 1:
The patent applies different widths to different arms: the first arm has a smaller width to reduce shadowing and improve temperature uniformity, while the second arm has a larger width to provide sufficient support strength. This local differentiation resolves the contradiction between temperature uniformity and support strength.
3Ease of operation
If a susceptor support portion is present at the rear surface of the susceptor, then the susceptor is supported, but a difference occurs in temperature between the shadowed part and other parts, leading to non-uniform temperature distribution
Solution Approach 1:
The patent optimizes the width parameters of the arms, making the first arm narrower than the second arm. This parameter change minimizes the shadowed area created by the support portion while maintaining adequate support capability, thereby reducing temperature differences between shadowed and non-shadowed regions.
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 ensures reduced heating influence on the susceptor, allowing for the production of high-quality epitaxial wafers with improved film thickness uniformity by maintaining susceptor stability and uniform temperature distribution.
Implementation Method 1
a difference occurs between the temperature of a shadowed part of the susceptor support portion of the susceptor, seen from a heating apparatus disposed downward
Data Source
AI summary
A susceptor support portion of the present invention includes a susceptor shaft and a substrate lift portion. The susceptor shaft includes a support column and a plurality of arms that extend radially from the support column, the substrate lift portion includes a support column and a plurality of arms that extend radially from the support column, the arm of the susceptor shaft includes a first arm, a second arm coupled to the first arm, and a third arm coupled to the second arm, from the support column side of the susceptor shaft, the second arm being provided with a through hole which passes through the second arm in a vertical direction, and a width of the first arm of the susceptor shaft is smaller than a width of the second arm of the susceptor shaft.