Semiconductor Die Ring Structure for Solder Bridging Control
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Solution Overview
Problem
Semiconductor die with solder connections on bond pads face issues such as solder ball collapse leading to solder bridging, and tilting of top semiconductor packages due to insufficient solder process control during high-temperature assembly processes.
Innovation Solution
A ring structure made of metal, such as copper, is formed around the solder locations on the semiconductor die to provide a rigid standoff and electrical isolation, preventing solder bridging and tilting during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solder pitch is reduced to increase component density, then higher component density is achieved, but solder bridging risk increases due to solder ball collapse
Solution Approach 1:
The patent introduces a restraining wall structure that segments the solder ball into isolated regions, preventing adjacent solder balls from merging during collapse. This segmentation approach allows tighter pitch while maintaining reliability by physically dividing the solder material into controlled compartments.
Solution Approach 2:
The restraining wall acts as an intermediary structure between adjacent solder balls, providing a physical barrier that prevents direct contact and bridging. This mediator structure enables closer spacing of solder joints without compromising electrical isolation.
2Ease of manufacture
If high assembly temperature is used for wirebonding, then proper wire bonding is achieved, but solder ball reformation is affected leading to bridging problems
Solution Approach 1:
The restraining wall is formed before the wirebonding process, establishing a protective structure that will constrain solder during the subsequent high-temperature wirebonding operation. This preliminary action ensures solder integrity is maintained throughout the manufacturing process.
Solution Approach 2:
The restraining wall provides beforehand protection against solder ball collapse and deformation during the high-temperature wirebonding process. By cushioning the solder from thermal and mechanical stresses before they occur, the structure prevents bridging problems.
3Device complexity
If top semiconductor package is attached directly to solder on bond pads, then simple attachment is achieved, but tilting occurs due to insufficient solder process control
Solution Approach 1:
The restraining wall introduces localized structural features around each solder joint, creating areas of enhanced rigidity and control. This local quality improvement provides precise positioning references that prevent tilting while maintaining overall attachment simplicity.
Data Source
AI summary
A semiconductor die includes a semiconductor surface including circuitry electrically connected to top-level bond pads exposed on a top surface of the semiconductor die, the top-level bond pads including inner bond pads and outer bond pads positioned beyond the inner bond pads. There is solder on at least the inner bond pads. A ring structure is positioned around a location of at least the inner bond pads.