Sloped Connecting Bump for Void-Free Underfill in Electronic Packages
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Solution Overview
Problem
In electronic device packaging, the reduced thickness and size of connecting bumps lead to voids in the under-fill insulating layer due to insufficient space, causing reliability issues with non-conductive adhesive layers remaining between bumps.
Innovation Solution
The formation of connecting bumps with sloped surfaces, which allows one end to extend on a step difference layer, preventing non-conductive adhesive layers from entering the interface between bumps and ensuring proper insulation and adhesion between semiconductor and package substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the package is decreased, then the compactness is improved, but the height of the connecting bumps is lowered and the size is decreased, causing the under-fill insulating layer to be insufficiently filled between bumps
Solution Approach 1:
The patent applies preliminary action by forming a protrusion on the connecting bump before the under-fill process. This protrusion structure is created in advance to prevent the under-fill insulating layer from being trapped in spaces between bumps, ensuring proper filling occurs during subsequent manufacturing steps without requiring rework or additional processes.
Solution Approach 2:
The connecting bump is segmented into distinct portions: a main body and a protrusion extending from it. This segmentation creates a functional division where the protrusion specifically addresses the under-fill trapping issue while the main body maintains electrical connection, allowing the bump to serve multiple purposes simultaneously.
2Area of moving object
If the interval between connecting bumps is narrowed, then the integration density is improved, but the space for under-fill insulating layer is reduced, leading to void formation
Solution Approach 1:
The protrusion is formed on the connecting bump before the under-fill process to proactively prevent void formation. By creating this structural feature in advance, the patent ensures that even when bumps are closely spaced, the under-fill insulating layer can properly fill the spaces without being trapped, thereby preventing voids and maintaining reliability.
Solution Approach 2:
The patent converts the potential harm of narrow bump spacing (which causes under-fill trapping and voids) into a benefit by adding the protrusion feature. This protrusion, while increasing bump complexity, actually improves the under-fill flow and eliminates void formation, turning the spacing constraint into an opportunity for enhanced reliability.
Data Source
AI summary
A package of an electronic device, a system including the same and a method for fabricating the same are provided. The package of the electronic device includes a substrate, a step difference layer and a connecting bump. The substrate allows a connecting contact part to be exposed on a surface thereof. The step difference layer covers the substrate so as to leave the connecting contact part exposed. The connecting bump is connected to the connecting contact part so that one end part of the connecting bump is extended on the step difference layer, and has a sloped upper surface formed by a step difference formed by the step difference layer.