Multi-TIM Semiconductor Package Structure for 3DIC Heat and Warpage
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Solution Overview
Problem
Three-dimensional integrated circuit (3DIC) package structures face challenges in heat dissipation and thermal stress, leading to warpage and cracks due to the difficulty in efficiently managing heat generated by dies with varying heat outputs and stress regions using a single thermal interface material (TIM) layer.
Innovation Solution
A multi-TIM structure with layers having different thermal conductivities and adhesion properties is implemented, where TIM layers with greater thermal conductivity are used in areas with higher heat output and those with better adhesion in regions experiencing greater stress, to enhance heat dissipation and secure the dies to a heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single TIM layer is used in 3DIC package structure, then the device complexity is reduced, but the heat dissipation efficiency deteriorates due to inability to address varying heat outputs and stress regions
Solution Approach 1:
The patent divides the TIM layer into multiple segments with different properties. Specifically, it uses a first TIM layer with first thermal conductivity and a second TIM layer with second thermal conductivity, where the thermal conductivities differ to address different heat dissipation needs in various regions of the semiconductor package.
Solution Approach 2:
The patent applies different TIM materials with different thermal conductivities to different locations based on local heat generation and stress characteristics. High thermal conductivity TIM is applied to regions with high heat output, while appropriate TIM is used in regions requiring different thermal or mechanical properties.
2Ease of manufacture
If a single TIM layer is used in 3DIC package structure, then the manufacturing process is simplified, but the thermal stress management deteriorates leading to warpage and cracks
Solution Approach 1:
The patent segments the TIM structure into multiple layers with different thermal and mechanical properties. The first TIM layer and second TIM layer are applied separately to different regions, allowing optimization of thermal stress distribution across the package structure.
Solution Approach 2:
The patent uses composite TIM structures combining different materials with complementary properties. The first TIM layer and second TIM layer have different thermal conductivities and mechanical properties, creating a composite system that manages both heat dissipation and thermal stress effectively.
3Loss of energy
If TIM layers with higher thermal conductivity are used in high heat output areas, then the heat dissipation efficiency is improved, but the adhesion capability may deteriorate in stress-prone regions
Solution Approach 1:
The patent applies TIM layers with different thermal conductivities to different locations based on local requirements. Regions with high heat output receive TIM with higher thermal conductivity for efficient heat dissipation, while other regions receive TIM optimized for adhesion and stress resistance.
Solution Approach 2:
The patent divides the TIM application into separate segments - a first TIM layer and a second TIM layer - allowing independent optimization of thermal conductivity and adhesion properties in different regions without compromising overall performance.
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 multi-TIM structure improves heat dissipation efficiency and reduces warpage by tailoring thermal conductivity and adhesion to specific needs, ensuring effective heat transfer and securing the semiconductor dies, thereby enhancing the reliability and performance of the 3DIC package.
Implementation Method 1
A first thermal interface material (TIM) layer is disposed in the first area and a second TIM layer is disposed in the second area
Implementation Method 2
ensuring effective heat transfer and securing the semiconductor dies
Data Source
AI summary
A semiconductor package structure includes a substrate, a first semiconductor and a second semiconductor over the substrate, and a multi-TIM structure disposed over the first semiconductor die and the second semiconductor die. The first semiconductor die includes a first heat output and the second semiconductor die includes a second heat output less than the first heat output. The multi-TIM structure includes a first TIM layer disposed over at least a portion of the first semiconductor die and a second TIM layer. A thermal conductivity of the first TIM layer is higher than a thermal conductivity of the second TIM layer. The first TIM layer covers the first semiconductor die.