Semiconductor Package Dam Structure for Underfill Leakage Control
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Solution Overview
Problem
Existing semiconductor packages face challenges in miniaturization and high-performance requirements while maintaining reliability and efficiency, particularly due to issues with underfill material leakage and interference with surrounding components.
Innovation Solution
A semiconductor package design incorporating a dam structure with dambars having a smaller width than other components, which reduces underfill material leakage and allows for a sufficient keep-out zone, enabling miniaturization and cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dam structure is formed to prevent underfill material leakage, then underfill material containment is improved, but device complexity increases
Solution Approach 1:
The dam structure is segmented into multiple dambars (first, second, third, and fourth dambars) arranged in a specific pattern around the inner substrate pad. This segmentation allows the underfill material to be contained effectively while distributing the structural complexity across multiple simpler elements rather than one complex continuous structure.
Solution Approach 2:
The dam structure merges multiple functional elements (dambars, connecting pads, fixing pads, and fixing vias) into a single integrated structure that simultaneously provides underfill containment, electrical connection, and mechanical fixation functions, thereby reducing overall device complexity.
2Length of moving object
If the width of dambars is reduced to secure keep-out zone margin, then miniaturization is improved, but manufacturing precision requirements increase
Solution Approach 1:
The dambars have different widths at different locations, with the width being smaller than the keep-out zone margin requirement. This local quality variation allows the structure to meet miniaturization goals while maintaining sufficient clearance from surrounding components like the outer substrate pad.
Solution Approach 2:
The dam structure including dambars with controlled widths is formed in advance during substrate processing, before chip mounting and underfill dispensing. This preliminary formation of the dam structure with precise width control simplifies subsequent manufacturing steps.
3Productivity
If the dam structure is formed simultaneously with substrate pad formation, then manufacturing time is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The dam structure formation process is merged with the substrate pad formation process, using the same plating and patterning steps to create both the inner substrate pad, outer substrate pad, and dam structure simultaneously. This integration reduces manufacturing cycle time while maintaining precision through unified process control.
Data Source
AI summary
A semiconductor package includes a substrate structure including: an inner substrate pad contacting a surface-mount semiconductor chip, and an outer substrate pad on an outer side of the inner substrate pad; a dam structure between the inner substrate pad and the outer substrate pad; and an underfill material layer including an underfill material filling an inside of the dam structure. The dam structure includes a plurality of dambars to reduce leakage of the underfill material in a direction from the inner substrate pad to the outer substrate pad, a plurality of connecting pads connecting the plurality of dambars to each other, a plurality of fixing pads in the substrate structure, and a plurality of fixing vias connecting the plurality of fixing pads and the plurality of connecting pads, respectively.