Semiconductor Package Structure for Warpage-Balanced Reliability
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Solution Overview
Problem
Existing semiconductor packages face challenges in controlling warpage and ensuring reliability due to structural imbalances between metal interconnection lines and through-electrodes, which affect the integrity and performance of the package.
Innovation Solution
Incorporating a mold layer with a higher coefficient of thermal expansion than the upper substrate, along with a buffer layer and strategically positioned bumps, to mitigate warpage and enhance reliability by balancing structural stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal interconnection lines and through-electrodes are used to electrically connect semiconductor chips to PCB, then electrical connectivity is achieved, but structural imbalance causes warpage that affects package integrity
Solution Approach 1:
The patent changes the physical parameters of the package structure by introducing a buffer layer with specific mechanical properties and adjusting the configuration of through-electrodes. The buffer layer's elasticity modulus is designed to be lower than that of the upper substrate, creating a compliant layer that absorbs thermal stress and prevents warpage while maintaining electrical connectivity through the through-electrodes.
Solution Approach 2:
The patent employs composite material structure by combining multiple layers with different material properties: the upper substrate, buffer layer, and mold layer form a composite structure where each layer contributes different mechanical characteristics. This composite approach allows the package to balance structural rigidity with stress absorption, resolving the warpage issue while maintaining overall integrity.
2Productivity
If multi-chip stacking is implemented to reduce device size, then integration density increases, but structural complexity and warpage control difficulty increase
Solution Approach 1:
The patent segments the package structure into distinct functional layers: upper substrate layer, buffer layer, mold layer, and interconnection elements. This segmentation allows each layer to be optimized independently for its specific function while simplifying the overall structural management of multi-chip stacks, making warpage control more manageable despite increased integration density.
Solution Approach 2:
The buffer layer acts as an intermediary element between the rigid upper substrate and the mold layer, mediating the mechanical stresses generated by multi-chip stacking. This intermediary layer absorbs and distributes thermal expansion forces, preventing stress concentration that would otherwise complicate the structural design of high-density multi-chip packages.
3Reliability
If through-electrodes penetrate both upper substrate and mold layer, then electrical connectivity is improved, but structural stress concentration increases causing reliability issues
Solution Approach 1:
The buffer layer serves as a mediator for the through-electrodes, providing a compliant pathway that reduces stress concentration. The through-electrodes pass through the buffer layer which absorbs mechanical stresses, allowing the electrical connection to be maintained while preventing stress-induced failures at the electrode-substrate interfaces.
Solution Approach 2:
The patent modifies the mechanical parameters of the buffer layer (lower elasticity modulus) to create a soft interface that accommodates the through-electrodes. This parameter change allows the through-electrodes to maintain electrical connectivity while the buffer layer's compliance reduces the stress concentration that would otherwise compromise structural strength.
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 solution effectively controls warpage and enhances the reliability of semiconductor packages, ensuring consistent performance and durability.
Implementation Method 1
The mold layer includes an insulating material of which a coefficient of thermal expansion is greater than that of the upper substrate
Data Source
AI summary
A semiconductor package includes an upper substrate having a first surface and a second surface which are opposite to each other, a semiconductor chip on the first surface of the upper substrate, a buffer layer on the second surface of the upper substrate, a mold layer between the second surface of the upper substrate and the buffer layer, a plurality of through-electrodes penetrating the upper substrate and the mold layer, an interconnection layer between the first surface of the upper substrate and the semiconductor chip and configured to electrically connect the semiconductor chip to the plurality of through-electrodes, and a plurality of bumps disposed on the buffer layer, spaced apart from the mold layer, and electrically connected to the plurality of through-electrodes. The mold layer includes an insulating material of which a coefficient of thermal expansion is greater than that of the upper substrate.