Microbump Underfill Cut Regions for Crack-Resistant Die Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cracks form in the underfill material and microbump underfill material during handling and use of fan-out wafer level packages due to mechanical and thermal stress, leading to potential damage in semiconductor dies and other components.
Innovation Solution
The method involves forming cut regions in the underfill material using milling or laser ablation to create vertically and horizontally extending surfaces, followed by applying an epoxy molding compound to enhance structural integrity and reduce delamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If underfill material is applied to fill gaps between semiconductor dies and substrate, then mechanical support and stress distribution are improved, but crack formation occurs at interfaces during thermal and mechanical stress
Solution Approach 1:
The underfill material is segmented into distinct regions: a first underfill material filling gaps between dies and substrate, and a second underfill material filling gaps between adjacent dies. This segmentation allows each region to be optimized for its specific function, preventing crack propagation across the entire interface while maintaining mechanical support.
Solution Approach 2:
Different underfill materials are used in different locations: the first underfill material (with higher glass transition temperature) is used at the die-substrate interface where thermal stress is highest, while the second underfill material is used between adjacent dies. This local optimization ensures each interface has the appropriate mechanical properties to resist crack formation under local stress conditions.
2Ease of manufacture
If conventional underfill material is used to fill gaps, then manufacturing simplicity is maintained, but delamination occurs at interfaces during handling and use
Solution Approach 1:
The patent uses composite underfill material structures with different glass transition temperatures in different regions. The first underfill material has a glass transition temperature of at least 100°C, while the second underfill material has a glass transition temperature below 100°C. This composite approach enhances interface stability and prevents delamination during handling and use, while still being compatible with conventional manufacturing processes.
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
The method enhances the resistance to crack generation in microbump underfill material, providing improved mechanical strength and reducing delamination risks in semiconductor die packaging.
Implementation Method 1
portions of the underfill material may be removed by irradiating a laser beam to the underfill material, whereby a material of the underfill material is ablated to form the at least one cut region
Data Source
AI summary
Devices and method for forming a chip package structure including at least one semiconductor die attached to a redistribution structure, a molding compound die frame laterally surrounding the at least one semiconductor die, and a first underfill material portion located between the redistribution structure and the at least one semiconductor die and contacting sidewalls of the at least one semiconductor die and sidewalls of the molding compound die frame. The first underfill material portion may include at least one cut region, in which the first underfill material portion may include a vertically-extending portion having a uniform lateral width and a horizontally-extending portion having a uniform vertical thickness and adjoined to a bottom end of the vertically-extending portion within each of the at least one cut region.