Tapered Conductive Structure Prevents Delamination in Semiconductor Packages
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Solution Overview
Problem
Semiconductor device packages face delamination and crack issues due to poor bonding between dielectric and conductive materials, especially during thermal cycles, and the existing under bump metallurgy does not adequately address these problems.
Innovation Solution
A semiconductor packaging device is designed with a first conductive structure having a tapered portion, a second conductive structure surrounding and in contact with the first, and a dielectric layer surrounding both, which enhances bonding and prevents delamination by forming a receiving space and using dome-shaped metal films to secure the connection elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If under bump metallurgy is used to provide strong bonding force, then bonding strength is improved, but delamination or crack damage occurs at the interface during thermal cycles
Solution Approach 1:
The conductive structure is designed with a tapered portion that changes the geometric parameters of the bonding interface. This tapered geometry gradually transitions from a narrow base to a wider top, distributing mechanical stress more evenly across the bonding interface and reducing concentration at sharp corners, thereby preventing delamination and crack formation during thermal cycling while maintaining strong bonding force
Solution Approach 2:
The conductive structure is formed as a multi-layer composite comprising a first conductive material and a second conductive material with different properties. This composite structure combines the advantages of both materials to achieve both strong bonding force and resistance to delamination, with each layer contributing different functional characteristics to the overall bonding interface
2Reliability
If dielectric material is used to package the semiconductor device, then packaging protection is provided, but poor bonding to conductive material causes delamination or crack issues
Solution Approach 1:
The tapered conductive structure acts as an intermediary element between the dielectric material and the connection element. Its specialized geometry and multi-layer composition improve the bonding interface, allowing the dielectric material to bond more effectively to the conductive structure while maintaining packaging protection, thus eliminating the poor bonding issue
3Reliability
If connection elements are disposed on conductive pads for external connection, then electrical connectivity is achieved, but delamination or crack damage occurs at the interface during manufacturing
Solution Approach 1:
The conductive structure's tapered geometry changes the physical parameters of the bonding interface, creating a gradual transition that distributes stress and prevents crack formation. This geometric parameter change maintains electrical connectivity while eliminating interface bonding failures during manufacturing processes
Solution Approach 2:
The multi-layer composite conductive structure combines different conductive materials to achieve both electrical connectivity and enhanced mechanical bonding strength. The composite nature allows optimization of each layer for specific functions, ensuring reliable electrical connection while preventing delamination and crack damage
Data Source
AI summary
A semiconductor package device includes a first conductive structure, a second conductive structure and a dielectric layer. The first conductive structure has a tapered portion. The second conductive structure surrounds the tapered portion of the first conductive structure and is in direct contact with a side wall of the tapered portion of the first conductive structure. The dielectric layer surrounds the tapered portion of the first conductive structure and is in direct contact with the side wall of the tapered portion of the first conductive structure.