Wafer Holding Member for Testing TAIKO-Thinned Wafers
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Solution Overview
Problem
Fully-automated probers cannot handle semiconductor wafers thinned by the TAIKO process, as they cannot be set in a wafer cassette case, requiring a dedicated loading mechanism and stage, and the thinned wafers cannot be measured by standard testers.
Innovation Solution
A wafer holding member is designed with a placement surface and a back surface of larger thickness than the difference between the small and large thickness portions of the thinned wafer, allowing the wafer to be attached and handled similarly to a standard wafer, enabling its use in existing test apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the TAIKO process is used to thin the semiconductor wafer by grinding only the inside, then the manufacturing yield is improved, but the wafer cannot be handled by fully-automated probers and standard testers
Solution Approach 1:
A wafer holding member is introduced as an intermediary component between the thinned semiconductor wafer and the test apparatus. The holding member has a thicker peripheral portion that compensates for the thinned wafer's insufficient thickness, enabling the combined structure to be handled by standard fully-automated probers and testers without requiring dedicated equipment
Solution Approach 2:
The wafer holding member is divided into a central portion and a peripheral portion with different thicknesses. The central portion is thinner to match the thinned wafer's requirements, while the peripheral portion is thicker to provide mechanical support and compatibility with standard equipment, allowing each segment to serve its specific function
2Length of moving object
If the semiconductor wafer is thinned by the TAIKO process, then the wafer thickness is reduced for specific applications, but the wafer requires a dedicated loading mechanism and stage
Solution Approach 1:
The wafer holding member serves as a mediator that bridges the thinned wafer and the standard test apparatus. By attaching the thinned wafer to the holding member with adequate thickness, the system can use existing standard loading mechanisms and stages without requiring dedicated complex equipment designed specifically for ultra-thin wafers
3Device complexity
If the wafer holding member thickness is insufficient, then the attachment structure is simple, but the wafer may crack during handling and movement
Solution Approach 1:
The wafer holding member employs parameter changes in its thickness distribution - the peripheral portion has a greater thickness than the central portion. This thickness parameter variation provides sufficient mechanical strength and rigidity to prevent wafer cracking during handling and movement, while maintaining a relatively simple overall attachment structure
Data Source
AI summary
A method of manufacturing a semiconductor device includes: a grind step of forming a small thickness portion and a large thickness portion surrounding the small thickness portion in plan view by grinding a back surface of a semiconductor wafer; a preparation step of preparing a wafer holding member including a wafer placement surface and a back surface opposite to the wafer placement surface and having a larger thickness than a difference between a thickness of the large thickness portion and a thickness of the small thickness portion; and a placement step of placing the semiconductor wafer on the wafer holding member so that the small thickness portion of the semiconductor wafer and the wafer placement surface of the wafer holding member are in contact with each other on the back surface side of the semiconductor wafer.