Heat Spreader Structure for Multi-TIM IC Package Cooling
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Solution Overview
Problem
The interference between different thermal interface materials (TIMs) applied to integrated circuit (IC) dies in IC packages compromises the thermal conduction performance, particularly affecting the coverage and corner thermal resistivity of the metal TIM on system on a chip (SoC) dies during the reflow process.
Innovation Solution
A method involving a heat spreader structure with a porous metal layer and perforated channels is used, where the metal TIM is treated first, with flux vapor exhausted through perforated holes, and a memory TIM is injected through these channels, followed by a cure treatment, ensuring consistent coverage and thermal contact without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple different TIMs are applied to different IC dies in the same IC package, then heat dissipation can be optimized for different die characteristics, but the TIMs interfere with each other during treatment processes causing coverage reduction and increased corner thermal resistivity
Solution Approach 1:
The heat spreader structure is segmented into multiple regions with different properties: a first region facing the SoC die and a second region facing the memory die. This segmentation allows each region to be optimized for its specific function - the first region for high-temperature reflow treatment of metal TIM and the second region for lower-temperature curing of memory TIM - thereby eliminating interference between different TIM treatment processes while maintaining optimal heat dissipation for each die type
Solution Approach 2:
Different regions of the heat spreader are given different local qualities - the first region has properties suitable for metal TIM bonding (withstanding reflow temperatures), while the second region has properties suitable for memory TIM curing (lower temperature processing). This local differentiation resolves the contradiction by allowing each TIM to be treated under its optimal conditions without interfering with the other, thus maintaining both high heat dissipation performance and manufacturing precision
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
Maintains sufficient coverage and thermal conductivity of the metal TIM on SoC dies while avoiding contamination and shrinkage, thereby reducing corner thermal resistivity and enhancing overall heat dissipation in IC packages.
Implementation Method 1
a porous metal on a bottom surface of the heat spreader structure and aligned between the first and second IC dies
Implementation Method 2
the perforated channel extends through the heat spreader structure, with a first port disposed at a top surface of the heat spreader structure and a second port disposed at a bottom surface of the heat spreader structure
Implementation Method 3
heat generated by the IC dies can be transmitted to a heat spreader structure mounted on the IC dies and dissipated
Data Source
AI summary
The present disclosure is directed to a structure of a semiconductor package with a heat spreader structure and a method of forming the structure. The method includes providing a substrate with first and second dies on the substrate, dispensing a first thermal interface material (TIM) on the first die, and mounting a heat spreader structure on the first and second dies. A porous metal of the heat spreader structure can be aligned between the first and second dies. The method further includes forming a first thermal contact between the first die and the heat spreader structure via the first TIM, injecting a second TIM on the second die through a perforated hole in the heat spreader structure, and forming a second thermal contact between the second die and the heat spreader structure via the second TIM.