Stacked Semiconductor Package With Dual TIM Layers for Heat and Rigidity
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Solution Overview
Problem
The increasing number of stacked semiconductor devices in modern electronic products poses challenges in achieving both structural and thermal stability, as existing adhesive technologies struggle to maintain performance, speed, and compact size while managing heat dissipation and mechanical durability effectively.
Innovation Solution
A semiconductor package design incorporating a substrate with vias, sequentially stacked semiconductor chips, and alternating thermal conductive layers with different thermal interface materials, where the lower layers have higher stiffness and the upper layers have higher thermal conductivity, along with chip terminals and non-conductive layers to enhance mechanical and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple adhesive members are used to stack multiple semiconductor devices, then the number of stacked devices increases, but structural stability and thermal stability deteriorate
Solution Approach 1:
The patent changes the physical and chemical parameters of the thermal interface material by adjusting the aluminum oxide content to 1-10 wt%, creating a material with optimized balance between stiffness and thermal conductivity. This parameter optimization allows the material to maintain structural stability while enabling higher device stacking
Solution Approach 2:
The patent uses composite thermal interface material consisting of aluminum oxide particles dispersed in a polymer matrix. This composite structure combines the high stiffness of aluminum oxide with the flexibility of the polymer, achieving both structural stability and improved thermal conductivity for supporting multiple stacked devices
2Quantity of substance
If multiple adhesive members are used to stack multiple semiconductor devices, then the number of stacked devices increases, but thermal stability deteriorates
Solution Approach 1:
The patent optimizes the thermal conductivity parameter of the interface material by controlling aluminum oxide content within 1-10 wt%. This parameter change enables efficient heat dissipation paths through the stacked devices, maintaining thermal stability even with increased device density
Solution Approach 2:
The thermal interface material acts as an intermediary substance between semiconductor devices, facilitating heat transfer from the devices to the substrate. This mediator material with optimized thermal properties enables effective thermal management in multi-device stacks
3Temperature
If thermal interface material with high thermal conductivity is used, then thermal stability improves, but structural stability deteriorates
Solution Approach 1:
The patent precisely controls the aluminum oxide content parameter within 1-10 wt% range, creating an optimal balance point where the material achieves sufficient thermal conductivity for heat dissipation while maintaining adequate stiffness for structural support of stacked devices
Solution Approach 2:
The patent creates local quality differentiation within the thermal interface material by distributing aluminum oxide particles non-uniformly in the polymer matrix. This local variation in filler concentration optimizes both thermal conduction pathways and mechanical strength in different regions of the material
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 design significantly improves thermal stability by facilitating efficient heat dissipation and structural stability by balancing mechanical durability and thermal conductivity, addressing the limitations of existing technologies in managing multiple stacked devices.
Implementation Method 1
a first thermal conductive layer between the substrate and the first chip stack, and at least a second thermal conductive layer between first semiconductor chips that are adjacent to each other
Implementation Method 2
The first thermal conductive layers include a first thermal interface material, the second thermal conductive layers include a second thermal interface material, a thermal conductivity of the second thermal interface material is greater than a thermal conductivity of the first thermal interface material
Data Source
AI summary
A semiconductor package includes a substrate, a first chip stack including a plurality of first semiconductor chips sequentially stacked on the substrate, and a second chip stack including a plurality of second semiconductor chips sequentially stacked on the first chip stack, and first and second pluralities of thermal conductive layers. The first thermal conductive layers are each between the substrate and the first chip stack, or between adjacent first semiconductor chips. The second thermal conductive layers are each between the first chip stack and the second chip stack, or between adjacent second semiconductor chips. A thermal conductivity of a second thermal interface material of the second thermal conductive layers is greater than a thermal conductivity of a first thermal interface material of the first thermal conductive layers, and a stiffness of the first thermal interface material is greater than a stiffness of the second thermal interface material.