Metal Foam Thermal Interface Containment for IC Packages
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Solution Overview
Problem
Integrated circuit (IC) devices face challenges with heat dissipation due to increased power consumption and density, leading to thermo-mechanical stresses and electromagnetic interference, which can result in failure modes like delamination and electromagnetic interference issues as ICs become smaller and more powerful.
Innovation Solution
Incorporating a metal foam structure that surrounds the IC devices and contacts the thermal interface material, acting as a barrier to prevent thermal interface material degradation and electromagnetic interference, while also providing a resilient structure to manage thermomechanical stresses and serve as a Faraday cage for EMI/RFI shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal interface material is used to provide heat transfer path, then thermal efficiency is improved, but the TIM may experience failure modes like voiding, hardening, and pump-out due to thermo-mechanical stresses
Solution Approach 1:
The patent employs a flexible metal foam structure that can deform to accommodate thermal expansion and contraction of IC devices during temperature cycling. This flexible containment structure prevents TIM pump-out and voiding while maintaining thermal contact, resolving the contradiction between heat transfer efficiency and TIM reliability under thermo-mechanical stress
Solution Approach 2:
The patent uses a composite structure combining metal foam (providing mechanical support and EMI shielding) with thermal interface material (providing heat transfer). This composite approach allows the system to simultaneously achieve effective heat transfer, TIM containment, and stress management, resolving the reliability issues of conventional TIM alone
2Volume of moving object
If IC devices are positioned closer together to reduce package size, then device density is improved, but electromagnetic interference between devices increases
Solution Approach 1:
The patent applies EMI shielding selectively around specific IC devices or high-frequency components using metal foam structures. This localized shielding approach contains electromagnetic interference at the source without requiring package-level shielding, enabling close device positioning while maintaining electromagnetic compatibility
Solution Approach 2:
The patent implements nested EMI shielding structures where metal foam shields are placed within the package architecture, surrounding individual IC devices or groups of devices. This nested configuration allows multiple devices to be positioned closely while each device remains electromagnetically isolated by its own shielding structure
3Temperature
If heat dissipation device is thermally attached to IC device with TIM, then heat removal is improved, but the TIM undergoes compression and elongation during temperature cycles causing failure modes
Solution Approach 1:
The patent places a flexible metal foam structure beforehand around the IC device and TIM assembly. This pre-positioned cushioning structure accommodates thermal expansion and contraction during temperature cycling, preventing compression and elongation of the TIM that would otherwise lead to voiding, hardening, or pump-out failure modes while maintaining thermal contact
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 metal foam effectively contains thermal interface material, preventing voiding and degradation, and shields against electromagnetic interference, enhancing the reliability and thermal management of IC devices by maintaining thermal contact and reducing the risk of damage from thermomechanical stresses and electromagnetic interference.
Implementation Method 1
the metal foam may be considered to act as a Faraday cage to shield the at least one integrated circuit device from external or ambient electromagnetic fields, such as radio frequency energy
Implementation Method 2
a thermal interface material between the at least one integrated circuit device and the heat dissipation device
Data Source
AI summary
An integrated circuit assembly may be formed comprising an electronic substrate, at least one integrated circuit device electrically attached to the electronic substrate, a heat dissipation device, a thermal interface material between the at least one integrated circuit device and the heat dissipation device, and a metal foam surrounding the at least one integrated circuit device and contacting the thermal interface material. The integrated circuit assembly may further include a stiffener attached to the electronic substrate and surrounding the at least one integrated circuit device, wherein the metal foam is disposed between the stiffener, the at least one integrated circuit device, the electronic substrate, and the heat dissipation device.