Semiconductor Wafer Support Ring Protrusions
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Solution Overview
Problem
Semiconductor wafers experience damage during heat treatment due to movement and adherence issues with traditional wafer support rings in vertical furnaces, leading to slips and backside damage.
Innovation Solution
The design of a semicircular support ring with a plateau or protrusions that elevate the semiconductor wafer, reducing contact with the support ring's surface and minimizing damage, and incorporating pins and slots to prevent adherence and facilitate secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the semiconductor wafer is heated during heat treatment, then the wafer and support ring expand due to thermal expansion, but this causes movement between the wafer and support ring leading to damage and slips
Solution Approach 1:
The support ring incorporates protrusions that change the contact parameters between the support ring and wafer. The protrusions create point contacts rather than surface contacts, allowing thermal expansion while maintaining stable positioning. This parameter change in the contact interface resolves the contradiction between heating and positioning stability.
Solution Approach 2:
The support ring is designed with segmented protrusions rather than a continuous surface. This segmentation allows different parts of the support ring to expand independently during heating, preventing accumulated stress and movement that would cause wafer damage while maintaining overall structural integrity.
2Reliability
If the semiconductor wafer contacts the support ring during heat treatment, then the wafer is supported, but the wafer adheres to the support ring causing damage during removal
Solution Approach 1:
The support ring features protrusions with curved surfaces rather than flat contact areas. The spherical or rounded geometry of the protrusions reduces the contact area and prevents adhesion by minimizing the surface area where thermal bonding could occur, while still providing sufficient support stability.
Solution Approach 2:
The design extracts the harmful adhesion effect by removing continuous contact surfaces and replacing them with discrete protrusions. This extraction of the contact interface eliminates the condition necessary for adherence while preserving the essential support function.
3Reliability
If traditional support rings are used, then the wafer is supported during heating, but the wafer edges contact the support ring causing backside damage
Solution Approach 1:
The support ring applies local quality by concentrating support forces at specific protrusion locations rather than along the entire rim. This localized support prevents edge contact damage while maintaining adequate support function, as the protrusions are positioned to support the wafer without contacting the vulnerable edge 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
The new support ring design minimizes contact with the semiconductor wafer's edge, reducing damage and preventing slips, while allowing for secure and damage-free removal, thus enhancing the quality of semiconductor wafers.
Implementation Method 1
The support ring minimizes contact with the semiconductor wafer... reducing damage
Implementation Method 2
As the semiconductor wafers and wafer support rings are heated, the semiconductor wafers and the wafer support rings may expand and move in relation to each other
Data Source
AI summary
A support ring for supporting a semiconductor wafer in a boat of a vertical furnace used in processing of the semiconductor wafer includes a semicircular segment. The semicircular segment has an upper surface, a lower surface opposite the upper surface, a radial inner wall defining an inner radius, and a radial outer wall defining an outer radius. The support ring further includes protrusions in the upper surface of the semicircular segment. The protrusions extend above the upper surface.