Holder Ring Geometry for Uniform Wafer Vapor Deposition
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Solution Overview
Problem
Existing wafer processing technologies suffer from non-uniformity in vapor deposition across the wafer surface due to edge effects, which are exacerbated by holder rings, and there is a need for improved efficiency in wafer processing.
Innovation Solution
A wafer boat system with holder rings featuring annular bodies and ring projections that vary in surface area and radius to compensate for deposition non-uniformities, allowing wafers to be spaced apart from the annular body, facilitating even vapor deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If holder rings with ring projections are used to support wafers, then wafers are spaced apart from the carrier allowing end effector access, but deposition non-uniformity increases due to shadowing effects from the ring projections
Solution Approach 1:
The annular body is designed with non-uniform surface area distribution along its circumferential direction, creating different local properties to compensate for the shadowing effects of ring projections. Specifically, the surface area is reduced in regions where ring projections are located and increased in adjacent regions, achieving local compensation for deposition non-uniformity while maintaining end effector accessibility.
2Productivity
If radial gas supply is used for vapor deposition, then processing efficiency is maintained, but edge effects cause non-uniform deposition with increased material at wafer edges
Solution Approach 1:
The holder ring with specifically designed annular body acts as an intermediary element between the carrier and the wafer. The non-uniform surface area distribution of the annular body modifies the vapor deposition pattern, compensating for edge effects caused by radial gas supply while maintaining processing efficiency.
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 system achieves a more uniform vapor deposition across the wafer surface, reducing non-uniformity by up to 1.65% compared to 7.5% in conventional systems, while maintaining efficient wafer processing.
Implementation Method 1
the present invention provides a wafer boat system... with an aim to improving uniformity of deposition across wafer surfaces... achieves a more uniform vapor deposition across the wafer surface
Data Source
AI summary
A wafer boat system comprises a carrier and a plurality of holder rings configured to support a wafer in the carrier. Each of the holder rings has an annular body and ring projections projecting from said annular body for contact with the wafer. At the ring projections, a local surface area of the annular body is small compared to a circumferential average or median of the local surface area of the annular body, in particular so as to at least partly compensate for a surface area of the respective ring projection, thereby promoting evenness of vapor deposition on wafers supported on the holder rings in the carrier. The reduced local surface area is preferably realized by a relatively large inner radius of the annular body at the ring projection. The carrier may provide a reference structure for automated wafer positioning.