Redistribution Pad Geometry for Crack-Resistant Semiconductor Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reliability of semiconductor packages is compromised by cracks in the insulating material layer around the connection bump, which existing technologies have not adequately addressed.
Innovation Solution
A semiconductor package design featuring a redistribution substrate with a connection via and redistribution layer, a redistribution pad with a concave-convex shape and protrusions, a dummy metal pattern, and a degassing opening, which reduces stress on the insulating layer and prevents cracks by distributing stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional redistribution pad design is used, then the manufacturing process is simple, but cracks occur in the insulating layer around the connection bump
Solution Approach 1:
The redistribution pad is divided into multiple protrusions (first, second, third protrusions) extending in different directions from the center. This segmentation distributes the stress that would otherwise concentrate at sharp corners, preventing cracks in the insulating layer while maintaining electrical connectivity.
Solution Approach 2:
Sharp corners of the redistribution pad are replaced with rounded corners having a predetermined radius. This curvature eliminates stress concentration points at the corners, preventing crack initiation in the insulating layer during thermal cycling and mechanical stress.
2Reliability
If the redistribution pad size is increased to improve electrical connection, then the electrical connectivity is enhanced, but stress on the insulating layer increases causing cracks
Solution Approach 1:
The large redistribution pad is segmented into multiple protrusions extending in different directions. This maintains the total pad area for electrical connectivity while distributing the mechanical stress across multiple smaller contact points with rounded corners, reducing stress concentration on the insulating layer.
Solution Approach 2:
Different regions of the redistribution pad have different geometric characteristics - the protrusions provide extended electrical contact area while the rounded corners at each protrusion tip locally reduce stress concentration. This local quality variation allows simultaneous optimization of electrical connectivity and stress distribution.
3Reliability
If dummy metal patterns are added to distribute stress, then crack prevention is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The stress distribution function previously requiring separate dummy metal patterns is merged into the redistribution pad structure itself. The multiple protrusions with rounded corners serve both as electrical connection elements and as stress-distributing features, eliminating the need for additional dummy patterns and simplifying the manufacturing process.
Data Source
AI summary
A semiconductor package includes: a redistribution substrate including a connection via and a redistribution layer electrically connected to each other, and a redistribution pad electrically connected to the redistribution layer by the connection via, a space pattern separating at least some of the redistribution pads from each other, a dummy metal pattern at least partially surrounded by the space pattern, and a degassing opening passing through at least one of the redistribution pad and the dummy metal pattern; a connection bump electrically connected to the redistribution pad; and a semiconductor chip on the redistribution substrate and including a connection pad electrically connected to the redistribution layer, the redistribution pad including a plurality of protrusions protruding from the same plane in directions different from each other and having a corner having a rounded shape, and the dummy metal pattern includes branch patterns each extending in directions different from one another.