Semiconductor Package Structure With Corner Underfill Trenches
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Solution Overview
Problem
The challenge in semiconductor packaging lies in managing tensile stress at the corners of semiconductor dies, which can lead to cracking of underfill materials and reduced reliability of 3D packaging structures, especially due to differences in thermal expansion coefficients between the substrate and the dies.
Innovation Solution
Incorporating trenches on the substrate directly under the open corners of the semiconductor dies and filling them with underfill material that extends into the substrate, thereby mitigating tensile stress and reducing the risk of cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trenches are added under die corners to reduce stress, then reliability improves, but device complexity increases
Solution Approach 1:
The substrate is segmented by introducing trenches that divide the substrate into distinct regions. These trenches are specifically positioned under die corners to segment the stress distribution, preventing stress concentration that would otherwise compromise package reliability.
Solution Approach 2:
Underfill material serves as an intermediary substance that is placed within the trenches and extends beyond them. This underfill material mediates the stress between the die and substrate, particularly at corner regions, by providing a compliant interface that accommodates thermal expansion differences.
2Strength
If underfill material is extended into substrate trenches, then stress concentration is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The trenches are formed in the substrate before the die attachment and underfill material application processes. This preliminary action allows the trenches to be pre-positioned and prepared, so that when underfill material is subsequently applied, it naturally flows into and fills the trenches without requiring complex precision control during the filling operation itself.
Solution Approach 2:
The underfill material's physical parameters (viscosity, flow characteristics) are controlled to enable it to naturally fill the trenches and extend beyond them in a predictable manner. By adjusting these parameters, the manufacturing process achieves the desired stress distribution without requiring extremely tight precision controls.
Data Source
AI summary
A package structure is provided. The package structure includes a package component over a redistribution structure, a substrate under the redistribution structure, and an underfill material over the redistribution structure and including a first extending portion in the structure. The package component has a first sidewall and a second sidewall connected to the first sidewall at a first corner. In a plan view, the first extending portion has a first sidewall passing through the first sidewall of the package component and a second sidewall opposite to the first sidewall of the first extending portion and passing through the second sidewall of the package component.