T-Shaped Bump Pad Structure to Prevent Package Peeling
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Solution Overview
Problem
The challenge of miniaturization and multifunctionality in semiconductor chips requires fine pitch connection terminals and micro-sized electrode pads, leading to issues such as peeling defects between bump pads and protective layers during manufacturing, which affect the reliability and productivity of semiconductor packages.
Innovation Solution
The semiconductor package design incorporates a T-shaped bump pad with a metal seed layer having orthogonal undercuts to enhance bonding strength, reducing peeling defects and improving reliability and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If micro-sized electrode pads and fine pitch connection terminals are used to achieve miniaturization, then the semiconductor chip size is reduced and functionality is increased, but peeling defects occur between bump pads and protective layers during manufacturing
Solution Approach 1:
The bump pad structure transitions from a conventional planar shape to a T-shaped configuration with orthogonal undercuts, adding dimensional complexity to enhance bonding. The undercuts extend in directions orthogonal to each other, creating a multi-dimensional interlocking structure that prevents peeling while maintaining miniaturization.
Solution Approach 2:
The bump pad employs an asymmetric T-shaped design with orthogonal undercuts rather than a symmetric conventional shape. This asymmetric geometry creates mechanical interlocking with the protective layer and metal seed layer, significantly improving bonding strength and preventing peeling defects during manufacturing processes.
2Reliability
If a conventional bump pad structure is used, then the manufacturing process is simple, but peeling defects occur reducing reliability and productivity
Solution Approach 1:
The bump pad is segmented into distinct functional regions: an upper structure for electrical connection, a lower structure for mechanical support, and orthogonal undercuts for enhanced bonding. The metal seed layer is also segmented to conformally coat different surfaces, creating a multi-component structure that addresses reliability while maintaining manufacturing feasibility.
Solution Approach 2:
The design introduces orthogonal undercuts that extend in directions perpendicular to each other, adding dimensional complexity to the bump pad structure. This multi-dimensional geometry creates mechanical interlocking that significantly improves bonding strength without requiring complex manufacturing processes.
3Area of moving object
If the bump pad area is reduced to achieve finer pitch, then more connection terminals can be packed, but bonding strength decreases leading to peeling defects
Solution Approach 1:
The T-shaped bump pad with orthogonal undercuts utilizes three-dimensional geometry to compensate for reduced planar area. The undercuts create mechanical interlocking in vertical and lateral dimensions, providing enhanced bonding strength despite the smaller overall footprint, enabling finer pitch without sacrificing reliability.
Solution Approach 2:
The bump pad structure combines multiple materials with complementary properties: a conductive material for electrical connection, and a metal seed layer with adhesive properties for enhanced bonding. This composite approach maintains bonding strength while reducing the required pad area through optimized material functionality.
Data Source
AI summary
A semiconductor package including a semiconductor chip, a redistribution layer structure disposed under the semiconductor chip, a bump pad disposed under the redistribution layer structure and having an upper structure of a first width and a lower structure of a second width less than the first width, a metal seed layer disposed along a lower surface of the upper structure and a side surface of the lower structure, an insulating layer surrounding the redistribution layer structure and the bump pad, and a bump structure disposed under the bump pad. A first undercut is disposed at one end of the metal seed layer that contacts the upper structure, and a second undercut is disposed at an other end of the metal seed layer that contacts the lower.