Silicon Wafer Orientation Shift to Reduce Thermal Bowing
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Solution Overview
Problem
Conventional silicon wafer production methods result in downward bowing of wafer portions protruding from the conveying blade during high-temperature heat treatment, leading to potential damage when the wafer is conveyed out of the furnace.
Innovation Solution
Shifting the crystalline orientation of the silicon wafer by a predetermined angle (preferably ≥25°) with respect to the transverse direction of the conveying blade's mounting face to reduce thermal deformation and bowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the wafer is heated to high temperature in the treating furnace, then the heat treatment or vapor phase growth can be performed, but the portions of the wafer protruding from the conveying blade are thermally deformed and bowed downward
Solution Approach 1:
The patent changes the orientation parameter of the wafer relative to the conveying blade by shifting the crystalline orientation (e.g., <100> orientation) by a predetermined angle (e.g., 45 degrees) with respect to the transverse direction of the mounting face. This parameter change in orientation reduces the bowing quantity of protruding portions during high-temperature heating, allowing the wafer to maintain its shape while undergoing heat treatment or vapor phase growth.
2Ease of operation
If the wafer is conveyed with portions protruding from the mounting face, then the wafer can be properly positioned, but the bowed portions may contact with members around the treating furnace to damage the wafer
Solution Approach 1:
By changing the orientation parameter of the wafer's crystalline structure relative to the conveying blade's transverse direction, the patent reduces the downward bowing of protruding portions. This ensures that even when portions of the wafer protrude from the mounting face for proper positioning, the reduced bowing prevents contact with surrounding furnace members, thereby maintaining wafer integrity and reliability during conveyance.
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
Effectively minimizes downward bowing of wafer portions, preventing damage during conveyance and maintaining wafer integrity.
Implementation Method 1
When portions 3a of the wafer 3 protruding from the mounting face of the conveying blade 4 are heated to a high temperature in the treating furnace 2, they are thermally deformed
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A process for producing a silicon wafer by conveying a (100) face silicon wafer into and from a treating furnace of a single wafer heat-treating apparatus or a vapor phase growth apparatus with a conveying blade having a mounting face capable of mounting only a specified region of the wafer inclusive of a center position of its rear face for subjecting the wafer to a heat treatment or a vapor phase growth, in which <010> or <001> orientation is shifted by a predetermined angle with respect to a transverse direction of the mounting face of the conveying blade.