Thin Wafer Cassette Magazine With Wide Slot Supports
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Solution Overview
Problem
Conventional cassette magazines fail to adequately support thin semiconductor wafers, leading to significant sag and deformation, which results in wafer breakage and identification errors during electrical testing.
Innovation Solution
A cassette magazine design with wider slot supports and tapered inner edges to minimize wafer sag, ensuring proper handling and identification by a robot arm, using materials like 6061-T6 Hard anodized Class III aluminum or engineering plastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cassette magazines with standard slot supports are used, then the structure is simple and easy to manufacture, but thin semiconductor wafers experience significant sag and deformation
Solution Approach 1:
The slot supports are designed with non-uniform cross-sections, featuring wider portions at the ends and narrower portions in the middle. This local variation in geometry provides enhanced support at the wafer edges where sag occurs most, while maintaining structural integrity throughout. The tapered edges further concentrate support where needed, addressing the wafer sag problem through localized structural optimization rather than uniform redesign.
2Reliability
If the slot supports are made wider to reduce wafer sag, then wafer support improves, but the cassette magazine becomes more complex and harder to manufacture
Solution Approach 1:
The slot supports utilize controlled variations in geometric parameters along their length, specifically transitioning from wider end portions to narrower middle portions with tapered edges. This parametric design allows the supports to provide maximum width and support where wafer sag occurs (at the edges) while reducing material usage and manufacturing complexity in the middle sections. The gradual parameter changes through tapering make the design more manufacturable compared to abrupt geometric transitions.
3Productivity
If thin wafers are handled in conventional cassette magazines, then handling speed is maintained, but wafer breakage occurs due to sag and deformation
Solution Approach 1:
The slot supports are designed to prevent wafer sag before handling operations occur. By providing pre-positioned support at the wafer edges through the optimized slot geometry, the wafer maintains its flatness and structural integrity throughout the electrical testing process. This preliminary support action prevents deformation that would otherwise lead to breakage during subsequent handling, ensuring both productivity and wafer strength are maintained.
Data Source
AI summary
Aspects and embodiments disclosed herein include a cassette magazine for thin semiconductor wafers having thicknesses of about 100 μm and diameters of 200 mm. The cassette magazine includes a plurality of slot supports configured to support sides of the thin semiconductor wafers. The plurality of slot supports have widths that provide sufficient support for the thin semiconductor wafers when disposed in the cassette magazine such that centers of the thin semiconductor wafers sag by less than about 0.3 cm. The cassette magazine includes first and second sidewalls coupled together by one or more rods or plates. The plurality of slot supports extend inward from both the first sidewall and the second sidewall.