Adhesive Sheet Surface Roughness for Wafer Grinding
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Solution Overview
Problem
Conventional adhesive sheets used in back-grinding processes for electronic parts often cause blocking during unwinding and result in minute irregularities on wafer surfaces, and lack transparency, which are critical issues in the manufacturing of electronic components.
Innovation Solution
An adhesive sheet with a sheet-like base material having specific average surface roughness ranges (0.1 μm to 3.5 μm on one surface and 0.05 μm to 0.7 μm on the other) and incorporating ethylene vinyl acetate for adjustable stiffness, along with an adhesive layer composed of acrylic polymers and curing agents, is used to reduce blocking and surface irregularities while maintaining transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional adhesive sheet is used in back-grinding, then the adhesive sheet can secure the work piece, but blocking occurs during unwinding of the rolled adhesive sheet
Solution Approach 1:
The invention changes the surface roughness parameter of the base material to resolve the contradiction. By controlling the average surface roughness within specific ranges (0.03-0.5 μm for the adhesive-contact surface, 0.03-2.0 μm for the other surface), the adhesive sheet achieves both reliable bonding and reduced blocking during unwinding, transforming the operational issue into a controlled physical parameter
2Reliability
If a conventional adhesive sheet is used in back-grinding, then the adhesive sheet can secure the work piece, but minute irregularities (waving) occur on the wafer surface
Solution Approach 1:
The invention applies parameter changes by precisely controlling the surface roughness of the base material. The specified roughness ranges (0.03-0.5 μm for the adhesive surface, 0.03-2.0 μm for the other surface) ensure that the adhesive sheet provides firm bonding while preventing minute irregularities on the ground wafer surface, thus resolving the contradiction between bonding reliability and manufacturing precision
3Ease of manufacture
If the protective sheet (adhesive sheet) is made transparent for inspection, then surface circuit patterns can be checked through the tape, but blocking and surface irregularities worsen
Solution Approach 1:
The invention resolves this contradiction by changing the surface roughness parameters within optimized ranges that simultaneously satisfy transparency for inspection and reliability for adhesive performance. The controlled roughness (0.03-0.5 μm on the adhesive surface) prevents excessive light scattering while maintaining adequate bonding, allowing both inspection capability and adhesive reliability
Solution Approach 2:
The invention uses a composite structure consisting of a base material and an adhesive layer with specific properties. The base material provides mechanical strength and controlled surface roughness for transparency and handling, while the adhesive layer provides bonding capability, creating a composite that satisfies both inspection and performance requirements
Data Source
AI summary
An adhesive sheet comprising a sheetlike base material and, superimposed on one major surface thereof, an adhesive layer, wherein the average surface roughness on one major surface of the base material is in the range of 0.1 to 3.5 μm and on the other major surface thereof is in the range of 0.05 to 0.7 μm. In this structure, the average surface roughness values on both the major surfaces of the base material as a constituent of the adhesive sheet are regulated so as to fall within respective specified ranges, so that not only can any blocking occurring in backwinding of reeled adhesive sheet be inhibited but also any occurrence of minute unevenness (waving) on the wafer surface after grinding can be inhibited, and further that the transparency of the adhesive sheet can be maintained.