Dual-Lid Package Assembly for Thermal Stress Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional package assemblies face challenges in mitigating package stress, particularly due to material cracking and delamination issues in polymer materials, which affect reliability.
Innovation Solution
A package assembly design featuring a dual lid structure, where the inner lid is made of a low coefficient of thermal expansion (CTE) material and the outer lid is polished to accommodate the inner lid, helping to mitigate stress on polymer materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single lid structure is used, then the device complexity is low, but package stress mitigation is insufficient leading to material cracking and delamination
Solution Approach 1:
The package lid is divided into two separate lids: an outer lid and an inner lid. The outer lid has a first coefficient of thermal expansion (CTE) and the inner lid has a second CTE that is lower than the first CTE. This segmentation allows each lid to manage different aspects of thermal stress, with the inner lid providing additional stress mitigation for polymer materials while the outer lid provides structural support and sealing.
2Ease of manufacture
If polymer materials are used in the package assembly, then ease of manufacture is improved, but material cracking and delamination occur due to thermal expansion differences
Solution Approach 1:
The patent changes the CTE parameter of the inner lid to be lower than that of the outer lid. This parameter change creates a gradient in thermal expansion properties that reduces stress concentration on polymer materials during thermal cycling, preventing cracking and delamination while maintaining ease of manufacture with conventional polymer materials.
3Reliability
If materials with different CTE values are used, then thermal expansion differences are managed, but manufacturing precision requirements increase due to the dual lid structure
Solution Approach 1:
The inner lid is nested within the outer lid structure, with the inner lid positioned inside the cavity formed by the outer lid. This nesting arrangement simplifies assembly by allowing the inner lid to be placed first, followed by the outer lid, reducing alignment complexity compared to side-by-side configurations while effectively managing thermal expansion differences through the CTE gradient.
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 dual lid structure effectively reduces the risk of polymer material crack and delamination, thereby enhancing the reliability of the package assembly by managing thermal expansion differences between materials.
Implementation Method 1
the inner lid may include an inner lid material having a coefficient of thermal expansion (CTE) less than 3 ppm/° C.
Data Source
AI summary
A package assembly includes a package substrate, an interposer module on the package substrate, and a package lid on the interposer module and attached to the package substrate. The package lid includes an outer lid including an outer lid material and including an outer lid plate portion. The package lid further includes an inner lid including an inner lid material different than the outer lid material and including an inner lid plate portion attached to a bottom surface of the outer lid plate portion.