Polygonal Semiconductor Package Layout for Stress Relief
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving efficient and reliable packaging of integrated circuits due to stress and delamination issues caused by coefficient of thermal expansion mismatches between dies and encapsulants, which affect the integration density and yield of 3D packaging and 3DIC devices.
Innovation Solution
A method involving the use of a de-bonding layer and a redistribution layer structure, combined with laser cutting to create a package structure with curved corners and specific cutting paths, allowing for the formation of polygonal packages with internal angles greater than 5, which reduces stress and improves reliability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging methods are used, then manufacturing simplicity is maintained, but stress and delamination occur due to coefficient of thermal expansion mismatches
Solution Approach 1:
The patent applies curvature by forming rounded corners at the package structure instead of sharp 90-degree angles. This is achieved through a multi-step cutting process that creates curved transition regions. The curved corners reduce stress concentration and prevent delamination caused by thermal expansion mismatches between different package materials, thereby improving package reliability without significantly increasing structural complexity.
Solution Approach 2:
The patent segments the package structure into distinct regions with different cutting paths. The first cutting path creates initial package shapes, while the second cutting path creates curved corners by removing material in a controlled sequence. This segmentation allows different portions of the package to be optimized for different functions - straight edges for structural integrity and curved corners for stress reduction.
2Productivity
If standard cutting paths are used, then manufacturing process is simple, but integration density is reduced due to stress and delamination
Solution Approach 1:
The curved corner design increases integration density by optimizing the use of package space and enabling more efficient thermal management. The curvature allows for better heat dissipation patterns and reduces the overall package footprint, allowing higher integration density without complicating the manufacturing process beyond a controlled multi-step cutting operation.
3Ease of manufacture
If sharp corners are used in package structure, then manufacturing is simpler, but stress concentration and delamination increase
Solution Approach 1:
The patent directly addresses stress concentration by replacing sharp corners with curved corners. The curved geometry distributes mechanical and thermal stress more evenly across the package structure, preventing delamination at the corners. While this requires an additional cutting step, the process remains relatively simple and can be integrated into existing manufacturing workflows.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the flexibility and reliability of package structures by reducing stress and delamination, thereby increasing the integration density and yield of 3D packaging and 3DIC devices.
Implementation Method 1
performing a second sawing process to remove the second die and form a recess, so that a cut second package is formed into a polygonal structure with the number of internal angles greater than or equal to 5
Data Source
AI summary
Provided are a package structure and a method of forming the same. The method includes providing a first package having a plurality of first dies and a plurality of second dies therein; performing a first sawing process to cut the first package into a plurality of second packages, wherein one of the plurality of second packages comprises three first dies and one second die; and performing a second sawing process to remove the second die of the one of the plurality of second packages, so that a cut second package is formed into a polygonal structure with the number of nodes greater than or equal to 5.