Vertical Wafer Boat Equal Sectional Areas
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Solution Overview
Problem
The existing vertical wafer boats experience uneven heat distribution due to differing lengths of wafer support parts, leading to deformation and potential slip of wafers during heat treatment, as the support parts receive varying amounts of heat, causing stress concentration and inclination.
Innovation Solution
The design ensures equal horizontal sectional areas for all wafer support parts and their corresponding support posts, with the support parts positioned between 65% to 75% of the wafer's radius, maintaining uniform heat distribution and minimizing deformation differences through bent and tapered shapes, thereby preventing wafer inclination and slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer support parts are made of long form to support wafers from outer peripheral part to 40-60% of radius, then wafer deformation is suppressed and slip is reduced, but uneven heat distribution occurs causing support member deformation and wafer inclination
Solution Approach 1:
The patent changes the geometric parameters of the support members, specifically making the horizontal sectional areas of all support members (including both support post and wafer support part) equal. This parameter adjustment ensures uniform heat absorption across all support members, preventing differential thermal expansion and maintaining wafer horizontal positioning accuracy while preserving the long-form support structure needed for slip prevention.
Solution Approach 2:
The patent applies local quality by giving each support member a tailored geometry (bent leg shape for first and second support members, tapered shape for third support member) while maintaining equal horizontal sectional areas. This allows each local region to have optimized heat distribution characteristics, ensuring uniform thermal expansion behavior across all support members despite their different positions and orientations.
2Adaptability or versatility
If the wafer support parts have different lengths, then the wafer can be supported at multiple positions, but the support members receive varying heat quantities causing deformation differences and wafer inclination
Solution Approach 1:
The patent changes the geometric parameters of the support members, specifically making the horizontal sectional areas of all support members (including both support post and wafer support part) equal. This parameter adjustment ensures uniform heat absorption across all support members, preventing differential thermal expansion and maintaining wafer horizontal positioning accuracy while preserving the long-form support structure needed for slip prevention.
Solution Approach 2:
The patent creates equipotentiality in terms of thermal conditions by ensuring all support members have equal horizontal sectional areas, which means they all absorb the same quantity of heat during the heat treatment process. This equalizes their thermal expansion behavior, preventing relative displacement and maintaining the stability of the wafer support system.
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 wafers are held without inclination, reducing stress concentration and preventing slip by maintaining equal heat quantities across all support parts, thus ensuring stable wafer positioning during heat treatment.
Implementation Method 1
the length of the wafer support parts 2a and 3a is different from the length of the wafer support part 4a... surface areas (volume) of the support members are different from each other to generate a difference in the heat quantity received during a heat treatment. Accordingly, the degrees of deformation due to a thermal expansion are different between the support members.
Data Source
AI summary
A vertical wafer boat includes a top plate, a bottom plate, three support posts, and wafer support parts. The support posts include a first and a second support posts arranged in right and left sides of a starting end side of a wafer inserting direction, and a third support post arranged in a center of a terminal end side of the wafer inserting direction. The wafer support parts include a first, second and third wafer support parts protruding in the horizontal direction from side surfaces of the first, second and third support posts, respectively. A total of horizontal sectional areas of the first wafer support part and the first support post, or the second wafer support part and the second support post, and a total of horizontal sectional areas of the third wafer support part and the third support post have a specific relationship.