Package Substrate Stress Buffer Pads for Warpage and Crack Control
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Solution Overview
Problem
As semiconductor packages become larger and more complex, ensuring mechanical stability becomes challenging, leading to warpage and cracking issues that increase failure rates and decrease reliability.
Innovation Solution
Incorporating stress buffer pads within the redistribution structures of the package substrate, which provide structural reinforcement by distributing tensile stress and inhibiting warpage and crack formation, while also improving insertion loss characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If semiconductor packages are made larger and more complex, then functionality and integration are improved, but mechanical stability deteriorates leading to warpage and cracking
Solution Approach 1:
Stress buffer pads are incorporated into the redistribution structure design before packaging, proactively compensating for thermal expansion differences and preventing warpage and cracking that would otherwise occur in larger, more complex semiconductor packages
Solution Approach 2:
The stress buffer pads modify the mechanical parameters of the redistribution structure by introducing additional conductive material layers with different stress characteristics, changing the overall stress distribution to accommodate thermal expansion differences in larger packages
2Strength
If stress buffer pads are added to redistribution structures, then mechanical integrity is improved, but device complexity increases
Solution Approach 1:
The stress buffer pads are merged with the existing redistribution conductive structures, combining mechanical reinforcement functionality with electrical interconnect functionality in a single integrated design, thereby reducing overall device complexity
Solution Approach 2:
The conductive structures serve multiple functions: they provide both electrical redistribution/interconnection and mechanical stress buffering, eliminating the need for separate structural reinforcement elements and reducing device complexity
3Reliability
If stress buffer pads are incorporated, then reliability is improved by reducing warpage and cracking, but manufacturing complexity increases
Solution Approach 1:
The stress buffer pads are combined with the redistribution conductive structure fabrication process, using the same deposition and patterning steps to create both the electrical interconnect and the mechanical reinforcement, thereby avoiding additional manufacturing complexity
Solution Approach 2:
The same conductive material layers used for electrical redistribution also provide mechanical stress buffering, eliminating the need for separate manufacturing processes and reducing overall manufacturing complexity while improving reliability
Data Source
AI summary
A package substrate and a method of fabrication thereof including stress buffer layers. Each stress buffer layer may be vertically spaced from and at least partially overlap with a corresponding bonding pad of the package substrate. The stress buffer pads may provide structural reinforcement to distribute tensile stress on the package substrate and inhibit warpage and crack formation in the package substrate. The stress buffer pads may additionally improve an insertion loss characteristic of the package substrate. Accordingly, semiconductor package performance, reliability and yields may be improved.