Semiconductor Package Non-Circular Vias Stress Distribution
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Solution Overview
Problem
The reliability of vias in semiconductor packages is compromised due to structural stress, leading to peeling and cracking issues, especially when exposed to harsh environments, as they become finer and more susceptible to interface defects.
Innovation Solution
A semiconductor package design that incorporates non-circular connection vias arranged to satisfy specific geometric relationships with connection metals, dispersing stress by widening the stress-concentrated surfaces and aligning long axes perpendicular to the metal centers, thereby reducing transmitted stress and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the vias are made finer to reduce component size, then the area occupied by vias is reduced, but the reliability deteriorates due to increased susceptibility to peeling and cracking
Solution Approach 1:
The patent applies asymmetry by changing the via cross-section from a conventional circular shape to an elliptical shape with different major and minor axis lengths. This asymmetric geometry allows the via to better distribute stress concentrations, particularly by orienting the longer major axis perpendicular to the stress direction from the connection metal, thereby improving reliability while maintaining reduced area
Solution Approach 2:
The patent changes the geometric parameters of the via by defining specific relationships between the major axis length (D1), minor axis length (D2), and the distance from the via center to the connection metal center (D3). The parameters satisfy the relationships: D1 > D2 and D1 ≥ 2×D3, which optimizes stress distribution and improves reliability while keeping the via area minimized
2Ease of manufacture
If conventional circular vias are used, then the manufacturing process is simple, but stress concentrates at the interface causing peeling and cracking
Solution Approach 1:
The patent replaces the symmetric circular via shape with an asymmetric elliptical shape. This asymmetry is specifically designed to distribute stress more evenly at the via interface with the connection metal, reducing stress concentration points that lead to peeling and cracking, while still being manufacturable using standard semiconductor fabrication processes
Solution Approach 2:
The patent transitions from a circular via (one-dimensional symmetry) to an elliptical via (two-dimensional asymmetry with different axis lengths). This dimensional change in the via cross-section geometry provides an additional degree of freedom to control stress distribution patterns, allowing optimization of stress concentration without complicating the manufacturing process
Data Source
AI summary
A semiconductor package is provided. The semiconductor package includes a connection structure, a semiconductor chip, and a connection metal. The connection structure includes a redistribution layer and a connection via layer. The semiconductor chip is disposed on the connection structure, and includes a connection pad. The connection metal is disposed on the connection structure and is electrically connected to the connection pad by the connection structure. The connection via layer includes a connection via having a major axis and a minor axis, and in a plan view, the minor axis of the connection via intersects with the connection metal.