Segmented Underfill and Edge Bond Layout for Void Venting
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Solution Overview
Problem
Traditional microelectronic packaging methods face issues with nonuniform underfill flow, leading to voids underneath electronic components, which can cause 'popcorn failure' due to temperature changes, especially in large devices where solder bumps are at higher risk of failure.
Innovation Solution
The implementation of isolated underfill regions and/or isolated edge bond regions adjacent to the edges of electronic devices, with strategically placed vent openings to provide pathways for outgassing and thermal management, reducing the risk of failure and allowing for selective application at high-stress areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional continuous underfill flow is applied underneath electronic components, then complete coverage and structural support are achieved, but voids are trapped leading to popcorn failure under temperature changes
Solution Approach 1:
The underfill material is applied in discrete segmented regions rather than continuous flow, creating isolated zones that prevent void entrapment while maintaining structural support at critical locations
Solution Approach 2:
Underfill material is selectively applied at specific locations such as corners and edges where stress concentration occurs, rather than uniform coverage, providing targeted reinforcement while allowing venting in other areas
2Strength
If underfill material is applied to secure the package to the substrate, then bonding strength is improved, but thermal management capability deteriorates due to insulation
Solution Approach 1:
Underfill material is selectively applied only at critical stress locations such as corners and edges, providing localized bonding strength while leaving central areas open for thermal management and outgassing pathways
3Reliability
If isolated underfill regions are applied at critical areas, then void formation is reduced and vent pathways are created, but structural support coverage is reduced
Solution Approach 1:
The underfill structure is segmented into isolated regions at critical locations rather than continuous coverage, creating inherent vent pathways between segments that prevent void entrapment while maintaining support where needed
Solution Approach 2:
Underfill regions are strategically positioned asymmetrically at corners and edges where stress concentration occurs, rather than uniform distribution, optimizing both void prevention and structural support efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach limits void size, enhances thermal management, and reduces the risk of failure by providing vent pathways and structural support, while maintaining reworkability and adaptability to various electronic devices and bonding configurations.
Implementation Method 1
vent openings to provide pathways for outgassing
Implementation Method 2
vent openings to provide pathways for outgassing and thermal management
Data Source
AI summary
Microelectronic structures with selectively applied underfill material and/or edge bond material are described. In an embodiment, isolated underfill regions and/or edge bond regions are applied to adjacent to one or more edges of an electronic device and form a plurality of vent openings along the one or more edges.