Ribbed Semiconductor Package Lid for CTE Stress and Delamination
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Solution Overview
Problem
The coefficient of thermal expansion (CTE) mismatch between materials used in semiconductor devices, such as silicon, substrates, and lids, leads to thermal stress, die crack, and delamination issues, affecting the thermal performance and mechanical stability of semiconductor packages.
Innovation Solution
The implementation of rib portions protruding from the lid structure towards the package structure to improve warpage and reduce delamination, combined with a thermal interface layer and a lid structure comprising a cover portion, ring portion, and rib portions to enhance mechanical strength and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If materials with different coefficients of thermal expansion are used in semiconductor devices, then functional performance is improved, but thermal stress and delamination occur
Solution Approach 1:
The patent introduces a gradient structure where the coefficient of thermal expansion changes gradually from the substrate through intermediate layers to the lid. This gradient CTE design allows materials with different thermal expansion properties to be used while reducing thermal stress by avoiding abrupt transitions, thus resolving the contradiction between material selection flexibility and thermal stress resistance.
Solution Approach 2:
The patent employs composite material structures with multiple layers having different thermal expansion coefficients, arranged in a gradient configuration. This composite approach enables the use of diverse materials for functional performance while the gradual transition between layers prevents delamination and reduces thermal stress.
2Strength
If a lid structure is added to improve mechanical strength, then structural integrity is enhanced, but warpage and delamination increase due to CTE mismatch
Solution Approach 1:
The lid structure incorporates a gradient coefficient of thermal expansion across its thickness, transitioning from matching the substrate CTE at the bottom to matching the package contents CTE at the top. This parameter gradient allows the lid to provide mechanical strength while accommodating thermal expansion differences, preventing warpage and delamination.
Solution Approach 2:
The patent addresses the CTE mismatch problem by introducing a dimensional gradient within the lid structure itself, rather than trying to match materials perfectly. The CTE varies through the thickness dimension of the lid, allowing it to bridge the thermal expansion gap between substrate and package contents while maintaining structural integrity.
3Temperature
If thermal interface layers are added to improve heat dissipation, then thermal performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent combines the thermal interface layer function with the lid structure itself, creating an integrated component that provides both structural support and thermal management. This merging reduces manufacturing complexity by eliminating separate assembly steps while maintaining effective heat dissipation through the gradient CTE design.
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 configuration reduces thermal stress and delamination, improves mechanical reliability, and enhances thermal performance by efficiently dissipating heat while maintaining structural integrity.
Implementation Method 1
a thermal interface layer and a lid structure comprising a cover portion, ring portion, and rib portions to enhance mechanical strength and thermal conductivity
Implementation Method 2
The coefficient of thermal expansion (CTE) mismatch between materials used in semiconductor devices, such as silicon, substrates, and lids, leads to thermal stress, die crack, and delamination issues
Data Source
AI summary
A semiconductor package includes a substrate, a package structure, and a lid structure. The package structure is disposed on the substrate. The lid structure is disposed over substrate, wherein the lid structure includes a main body covering and surrounding the package structure and a plurality of rib portions protruded from the main body and extended toward the package structure.