Semiconductor Package Joint Pad Structure for Crack-Resistant Bonding
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Solution Overview
Problem
As electronic devices shrink, joining multiple semiconductor packages in a limited space becomes challenging due to mechanical property differences leading to cracks and delamination, reducing the reliability of semiconductor devices.
Innovation Solution
The use of adhesion layers like titanium and chromium, in contact with the semiconductor package, and a die attach film with slanted sidewalls to cover end portions of joint pads and adhesion layers, ensuring direct contact and similar mechanical properties, thereby reducing cracks and delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple semiconductor packages are joined in a limited space, then device integration density is improved, but mechanical property differences cause cracks and delamination
Solution Approach 1:
An adhesion layer is introduced as an intermediary between the joint pad and the die attach film. This adhesion layer has mechanical properties that are similar to both the joint pad and the die attach film, acting as a buffer that reduces stress concentration and prevents cracks from propagating through the bonding interface, thereby maintaining bonding reliability while enabling high integration density
Solution Approach 2:
The bonding structure is designed as a composite system comprising multiple layers with different mechanical properties: the joint pad, the adhesion layer with intermediate mechanical properties, and the die attach film. This composite structure allows each layer to contribute its specific mechanical characteristics, creating a gradient that reduces stress concentration and prevents delamination while enabling multiple packages to be joined in limited space
2Area of stationary object
If adhesion layers and joint pads are exposed, then bonding area is increased, but mechanical stress causes delamination at exposed ends
Solution Approach 1:
The die attach film forms a protective covering over the adhesion layer and joint pad. This thin film structure provides mechanical protection to the exposed ends of the adhesion layer and joint pad, reducing stress concentration at the edges and preventing delamination while allowing the bonding area to be maximized for high integration density
Data Source
AI summary
The present disclosure describes a structure that joins semiconductor packages and a method for forming the structure. The structure includes an adhesion layer in contact with a first semiconductor package and a first joint pad in contact with the adhesion layer. The structure further includes a film layer disposed on the first semiconductor package and the first joint pad, where the film layer includes a slanted sidewall, the slanted sidewall covers an end portion of the adhesion layer and a first portion of the first joint pad, and the slanted sidewall exposes a second portion of the first joint pad. The structure further includes a solder ball attached to the second portion of the first joint pad and a second joint pad of a second semiconductor package.