Variable Width Plating Ring for Semiconductor Wafer Electroplating
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Solution Overview
Problem
The existing semiconductor wafer electroplating processes, particularly in flip-chip processing, suffer from defects such as missing, small, or deformed solder bumps due to the overlap of the plating ring on the edge die areas, leading to yield loss.
Innovation Solution
A plating ring with varying width is used to minimize overlap near the edge die areas of the semiconductor wafer, reducing the width of the ring in specific portions to avoid overlap and thus potential defects during electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a standard plating ring with uniform width is used to secure the wafer during electroplating, then the wafer positioning is stable, but overlap occurs on the edge die areas causing defects such as missing bumps, small bumps, and deformed bumps
Solution Approach 1:
The plating ring is designed with non-uniform width where the width varies at different angular positions. Specifically, the ring width is reduced in regions that would overlap with edge die areas during electroplating, while maintaining sufficient width in other regions to provide stable wafer positioning. This local variation in geometry allows the same plating ring structure to simultaneously achieve both stable positioning and avoid overlap-induced defects on edge dies.
2Manufacturing precision
If the plating ring width is reduced to avoid overlap on edge dies, then defect formation is reduced, but the wafer positioning stability may be compromised
Solution Approach 1:
The plating ring incorporates position-dependent width characteristics where the width is locally adjusted based on the specific angular position. The ring maintains adequate width in regions that contact or near edge die areas to prevent overlap defects, while preserving sufficient structural mass in other regions to ensure overall wafer positioning stability during the electroplating process.
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 approach effectively reduces defects in edge dies, enhancing the die yield by minimizing overlap and associated yield loss issues during the electroplating process.
Implementation Method 1
A plating ring for holding the semiconductor wafer in position during electroplating is also included
Implementation Method 2
semiconductor wafer electroplating processes
Data Source
AI summary
A system and method increase yield from semiconductor wafer electroplating. The aspects include a semiconductor wafer, the semiconductor wafer comprising a plurality of die areas. A plating ring for holding the semiconductor wafer in position during electroplating is also included, the plating ring substantially surrounding a circumference of the semiconductor wafer and having a width that varies in order to avoid overlap near edge die areas of the semiconductor wafer.