Semiconductor Package TIM Structure for Thermal Stress Relief
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Solution Overview
Problem
The miniaturization of electronic products has led to challenges in heat dissipation due to thermomechanical stresses and thermal interface material degradation, particularly between semiconductor dies, heat spreaders, and thermal interface materials, resulting in reliability and performance issues.
Innovation Solution
A package structure is developed with a thermal interface material (TIM) structure that includes a dielectric dam and thermally conductive members, where the dielectric dam absorbs thermo-mechanical stresses and the conductive members provide efficient heat dissipation, using a conductive material pattern bonded to the semiconductor dies and a heat dissipating component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If rigid thermal interface material is used, then thermal conductivity is improved, but reliability deteriorates due to thermomechanical stresses and cracking
Solution Approach 1:
The patent changes the physical state of the thermal interface material from rigid to compliant, allowing it to deform and absorb thermomechanical stresses while maintaining good thermal contact. This parameter change resolves the contradiction by preserving thermal conductivity through continuous contact while improving reliability through stress absorption.
Solution Approach 2:
The patent uses a composite structure combining a dielectric dam layer with a compliant thermal interface material. The dielectric dam provides structural support and stress management, while the compliant material ensures thermal conductivity and reliability by adapting to dimensional changes during temperature cycling.
2Temperature
If thermal interface material is used to improve heat dissipation, then thermal performance is improved, but degradation occurs during temperature cycling
Solution Approach 1:
The patent employs a dynamic thermal interface material that can change its physical properties in response to temperature cycling. The compliant material dynamically adjusts its shape and position to maintain optimal thermal contact throughout the operational lifetime, preventing degradation and extending duration of action.
Solution Approach 2:
The dielectric dam layer serves as a pre-configured cushioning structure that absorbs thermomechanical stresses before they can damage the thermal interface material or semiconductor die. This beforehand cushioning prevents degradation during temperature cycling and extends the operational duration.
3Temperature
If coefficient of thermal expansion differences are present, then thermal interface is achieved, but thermomechanical stresses arise causing delamination and cracking
Solution Approach 1:
The patent introduces a dielectric dam layer as an intermediary structure between the rigid heat spreader and the compliant thermal interface material. This intermediary absorbs and distributes thermomechanical stresses, preventing stress concentration that would cause delamination and cracking, thereby maintaining both thermal interface quality and 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 reduces thermal resistance and enhances the reliability and heat dissipation efficiency of the package structure, preventing delamination and cracking issues associated with traditional rigid thermal interface materials.
Implementation Method 1
thermo-mechanical stresses may arise due to differences in the coefficients of thermal expansion between the heat spreader, the semiconductor die, and the thermal interface material
Implementation Method 2
the conductive members provide efficient heat dissipation
Data Source
AI summary
A manufacturing method of a package structure includes: coupling a device package to a package substrate, where the device package includes semiconductor dies encapsulated by an insulating encapsulation and electrically coupled to the package substrate; forming a first dielectric pattern on the device package opposite to the package substrate, where the first dielectric pattern includes openings corresponding to the semiconductor dies of the device package; forming a thermal conductive material on the semiconductor dies of the device package and in the openings of the first dielectric pattern; placing a heat dissipating component over the device package and the package substrate, the heat dissipating component being in contact with the first dielectric pattern and the thermal conductive material; and performing a thermal treatment process on the first dielectric pattern and the thermal conductive material to form a thermal interface material structure coupling the heat dissipating component to the device package.