Semiconductor Wafer Warp Direction Adjustment for Flatness
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor wafers with double-side polishing struggle to maintain flatness due to warp direction inconsistencies and debris from laser marking, leading to degradation in wafer flatness.
Innovation Solution
A method that involves slicing, warp direction adjustment to uniform warps in one direction before chamfering and double-side polishing, ensuring consistent warp direction during chamfering and polishing to prevent flatness degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If wafers are reversed to uniform warp directions before double-side polishing, then warp direction uniformity is improved, but flatness is degraded
Solution Approach 1:
The invention performs warp direction adjustment by reversing wafers before chamfering, but performs double-side polishing after chamfering. This preliminary action of uniforming warp directions before chamfering, while delaying polishing until after chamfering, allows the chamfered edges to provide stable positioning that prevents flatness degradation during polishing, thus resolving the contradiction between achieving warp uniformity and maintaining flatness
Solution Approach 2:
The invention segments the manufacturing process into distinct stages: first performing warp direction adjustment and chamfering, then performing double-side polishing. This segmentation allows the positioning function (chamfering) to be separated from the polishing function, enabling warp uniformity to be achieved without compromising flatness during the subsequent polishing stage
2Manufacturing precision
If double-side polishing is performed to polish both surfaces of wafers, then surface quality is improved, but flatness degradation occurs due to warp direction inconsistencies
Solution Approach 1:
The invention performs chamfering as a preliminary action before double-side polishing. The chamfered edges create stable positioning features that ensure consistent wafer orientation during polishing, thereby preventing flatness degradation while still achieving high surface quality through the double-side polishing process
Solution Approach 2:
The chamfered edges act as an intermediary element between the wafer and the polishing process. These chamfered portions provide a mechanical reference that mediates the positioning of wafers during double-side polishing, ensuring that warp direction inconsistencies do not lead to flatness degradation while allowing the polishing to achieve the desired surface quality
Data Source
AI summary
A method for manufacturing a semiconductor wafer including: slicing off a plurality of wafers from an ingot; chamfering outer peripheral portions of the plurality of sliced wafers; and performing double-side polishing to polish both surfaces of each wafer whose outer peripheral portion is held by a carrier, wherein includes performing warp direction adjustment to uniform directions of warps of the plurality of wafers in one direction after the slicing and before the chamfering, and the chamfering and the double-side polishing are performed in a state where the directions of the warps of the plurality of wafers are uniformed in one direction after the warp direction adjustment. Consequently, it is possible to provide the method for manufacturing a semiconductor wafer which can suppress degradation of flatness of the double-side polished wafers even in case of uniforming the directions of the warps of the wafers in one direction before the double-side polishing.