IC Package Lid Interface Using Hybrid TIMs for Heat and Stress
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Solution Overview
Problem
Existing semiconductor packaging technologies face challenges in effectively dissipating heat and ensuring structural integrity, particularly in 3DICs, where the package structure may lack sufficient heat dissipation and structural strength, leading to potential performance degradation and physical damage.
Innovation Solution
A hybrid arrangement of two types of thermal interface materials (TIMs) and adhesives are used, where a first TIM with higher thermal conductivity and a second TIM with lower Young's modulus are applied to absorb stress, combined with a lid or ring to dissipate heat and provide structural rigidity, ensuring effective heat dissipation and stress absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal lid is bonded to the package substrate to dissipate heat and increase structural integrity, then heat dissipation and structural strength are improved, but the package structure becomes more complex and the manufacturing process becomes more difficult
Solution Approach 1:
The patent employs a hybrid arrangement combining two different types of thermal interface materials (TIMs) with distinct properties. The first TIM has higher thermal conductivity for efficient heat transfer, while the second TIM has lower Young's modulus for stress absorption. This composite material approach allows simultaneous optimization of heat dissipation and stress management without increasing structural complexity
Solution Approach 2:
The thermal interface material layer is segmented into two distinct functional regions: one region uses a high thermal conductivity TIM for heat dissipation, while another region uses a low Young's modulus TIM for stress absorption. This segmentation allows each material to perform its specialized function independently, resolving the contradiction between heat dissipation efficiency and stress absorption capability
2Strength
If a metal lid is bonded to the package substrate to provide structural rigidity, then structural strength is improved, but the package structure becomes more complex
Solution Approach 1:
The patent uses a composite adhesive system combining two different adhesive materials with complementary properties. One adhesive provides high bond strength for structural integrity, while the other provides flexibility for stress absorption. This composite adhesive approach achieves both structural strength and stress management without requiring additional structural components
Solution Approach 2:
The hybrid adhesive system performs multiple functions simultaneously: it provides structural bonding, stress absorption, and thermal management. By integrating these multiple functions into a single adhesive layer composition, the patent avoids increasing package structure complexity while achieving enhanced structural strength
3Ease of manufacture
If a single type of thermal interface material is used, then the manufacturing process is simpler, but both heat dissipation and stress absorption cannot be optimized simultaneously
Solution Approach 1:
The patent applies different TIM properties to different local regions or layers of the thermal interface. The first TIM with higher thermal conductivity is positioned where heat dissipation is critical, while the second TIM with lower Young's modulus is positioned where stress absorption is needed. This local quality differentiation optimizes performance without significantly complicating the manufacturing process
Solution Approach 2:
The patent creates a composite TIM system where two materials with complementary properties are combined in a single interface layer. This composite approach allows simultaneous optimization of heat dissipation and stress absorption within one integrated structure, maintaining manufacturing simplicity while enhancing reliability
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 hybrid TIM and adhesive arrangement enhances heat dissipation and structural integrity, preventing warping and delamination while maintaining stress absorption capabilities, thereby improving the performance and reliability of semiconductor packages.
Implementation Method 1
a first thermal interface material... with higher thermal conductivity... to dissipate heat
Implementation Method 2
a second thermal interface material... with lower Young's modulus... to absorb stress
Data Source
AI summary
A package structure is provided. The package structure includes a substrate, a die bonded to the substrate, a lid disposed over the die and the substrate, and an interface structure sandwiched between the die and the lid and including a first thermal interface material disposed at corners of a top surface of the die, and a second thermal interface material disposed a rest of the top surface of the die. A Young's modulus of the first thermal interface material is smaller than a Young's modulus of the second thermal interface material.