Multi-Angle Wafer Edge Polishing Drum for Uniform Bevel Shaping
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Solution Overview
Problem
Existing edge polishing drums for wafers fail to uniformly polish the edge areas, resulting in shape variability of the polished wafers.
Innovation Solution
The edge polishing drum features a body part with a polishing part having an inner surface with distinct first and second areas at different angles, and a tilted rotation axis, ensuring uniform polishing of the edge front and back bevels by controlling the polishing amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform polishing drum is used, then the polishing process is simple, but the edge shape uniformity deteriorates
Solution Approach 1:
The polishing drum's inner surface is divided into multiple regions with different polishing angles. Specifically, the drum includes a first polishing surface with a first polishing angle and a second polishing surface with a second polishing angle, where the angles differ to address different edge regions of the wafer. This local differentiation allows each surface to optimize polishing for its specific zone, achieving uniform edge shapes across the entire wafer perimeter.
Solution Approach 2:
The polishing drum employs asymmetric angle configuration where the first polishing angle and second polishing angle are deliberately made different from each other. This asymmetry enables the drum to compensate for the natural variability in edge shapes that occurs during wafer processing, transforming a uniform symmetric drum into an asymmetric tool that produces symmetric uniform results.
2Device complexity
If the polishing part has a single angle, then the structure is simple, but the polishing uniformity across different edge areas deteriorates
Solution Approach 1:
The polishing part incorporates distinct local regions with differentiated polishing angles. The first polishing surface operates at a first polishing angle while the second polishing surface operates at a second polishing angle, creating localized optimization zones that address the specific geometric requirements of different edge areas on the wafer.
Solution Approach 2:
The polishing part is segmented into multiple functional surfaces rather than using a single uniform surface. By dividing the polishing interface into separate segments with different angular configurations, the system can independently optimize each segment for its specific polishing task, thereby achieving overall uniformity across the entire edge.
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 enhances the roundness and flatness of the wafer edges, reducing shape variability and achieving a more uniform edge shape.
Implementation Method 1
a polishing part extending inclinedly from an edge of the body part toward a first face of the body part... the second surface includes a first area having a 2-1th angle with respect to the first face of the body part, and a second area having a 2-2th angle with respect to the first face of the body part
Data Source
AI summary
An edge polishing drum for wafers is disclosed. The edge polishing drum includes a body part having a disc shape, and a polishing part extending inclinedly from an edge of the body part toward a first face of the body part. The polishing part includes an inner surface surrounding a polishing area adjacent to the first face of the body part. The inner surface of the polishing part includes a first surface extending from the first face of the body part, and a second surface configured to contact an edge area of a wafer to be polished. The second surface includes a first area having a 2-1th angle with respect to the first face of the body part, and a second area having a 2-2th angle with respect to the first face of the body part. The first area is disposed between the first face of the body part and the second area.