Package Substrate Through Holes Intercept Crack Propagation
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Solution Overview
Problem
Electronic devices are prone to short circuits due to crack propagation when subjected to impact, which can occur during drops, leading to unreliable connections in the wire patterns of package substrates.
Innovation Solution
A package substrate design featuring a pattern layer with a wire pattern, solder pad, and strategically placed through holes adjacent to the boundary between the wire pattern and solder pad, which distribute stress and prevent crack propagation by providing a path for stress relief, thereby preventing short circuits. The through holes are positioned to intercept cracks and redirect stress, ensuring the integrity of the electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through holes are added to the pattern layer to prevent crack propagation, then reliability is improved, but device complexity increases
Solution Approach 1:
The pattern layer is segmented by introducing through holes that divide the continuous conductive paths into separate sections. These through holes act as discontinuities that prevent crack propagation along the wire patterns and solder pads, thereby improving reliability without requiring fundamental redesign of the entire package substrate structure.
Solution Approach 2:
The through holes serve as intermediary elements that intercept and redirect stress and crack propagation paths. By positioning these holes at critical locations near boundaries between wire patterns and solder pads, they mediate the stress distribution and prevent direct crack transmission across electrical connections.
2Strength
If the wire pattern width is increased near the boundary to prevent crack propagation, then strength is improved, but area occupied by the pattern layer increases
Solution Approach 1:
The wire pattern width is modified locally only in the region adjacent to the boundary between the wire pattern and solder pad, rather than increasing the width throughout the entire wire pattern. This localized widening provides enhanced crack resistance at the critical stress concentration area while maintaining the original compact dimensions elsewhere, thus improving strength without significantly increasing the overall area occupied by the pattern layer.
Data Source
AI summary
A package substrate includes: a body layer; and a pattern layer formed on a surface of the body layer. The pattern layer includes: a wire pattern; a solder pad connected to the wire pattern; and a through hole adjacent to a boundary between the wire pattern and the solder pad and vertically penetrating the pattern layer. A semiconductor package and an electronic device are disclosed.