Liquid Metal Polymer TIM for Thin Bondline Heat Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thermal interface materials (TIMs) face challenges in achieving both low contact resistance at material interfaces and low thermal resistance through the material, often requiring high pressure for installation and having limitations in thermal conductivity.
Innovation Solution
A TIM comprising a polymer with dispersed liquid metal droplets, applied in an uncured state to conform to surfaces, which is then cured to form a bondline distance of no greater than 150 microns, allowing for low contact and thermal resistance with reduced installation pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure is applied during TIM installation, then contact resistance is reduced, but installation complexity and risk of damage increase
Solution Approach 1:
The patent changes the viscosity parameter of the TIM by using a polymer in an uncured state during installation. This uncured polymer has lower viscosity and higher flexibility, allowing it to conform to surfaces and achieve low contact resistance without requiring high installation pressure. After installation, the polymer is cured to provide structural stability.
2Reliability
If the TIM bondline is made thin to reduce thermal resistance, then thermal performance improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses a flexible polymer matrix that can be applied as a thin film and conforms to the bonding surfaces. This flexibility allows the TIM to achieve thin bondline thickness for reduced thermal resistance while the polymer's compliance compensates for surface irregularities, reducing the need for high manufacturing precision.
3Reliability
If liquid metal droplets are used to improve thermal conductivity, then thermal resistance through material is reduced, but liquid metal pump-out during thermal cycling increases
Solution Approach 1:
The patent creates a localized environment for the liquid metal droplets by embedding them within the polymer matrix. The polymer provides a confining structure that holds the liquid metal droplets in place during thermal cycling, preventing pump-out while allowing the droplets to maintain thermal conduction pathways.
Solution Approach 2:
The composite structure of polymer matrix with embedded liquid metal droplets provides both the high thermal conductivity of liquid metal and the structural stability of the polymer. The polymer phase acts as a stabilizing medium that prevents liquid metal migration while the liquid metal phase provides thermal conduction, resolving the contradiction between thermal performance and compositional stability.
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 enables efficient thermal conductivity with low contact resistance and reduced pressure requirements, maintaining thermal performance through the material while inhibiting liquid metal droplet pump-out during thermal cycling.
Implementation Method 1
The low thermal resistance through the material can be enabled by liquid metal droplets, including the size and/or shape of the liquid metal droplets
Implementation Method 2
The low contact resistance can be enabled by the application of the polymer in an uncured state so that the polymer and liquid metal droplets can conform to the surface of the layer
Implementation Method 3
Further, curing the polymer can inhibit pump out of the liquid metal droplets
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The present disclosure relates to an integrated circuit assembly that comprises a die, an upper layer and a thermal interface material. The thermal interface material is disposed in contact with the die and the upper layer. The thermal interface material comprises a polymer and liquid metal droplets dispersed throughout the polymer. A bondline distance formed between the die and the upper layer is no greater than 150 microns. The liquid metal droplets are in a liquid phase at least at a temperature in a range of -19 degrees Celsius to 30 degrees Celsius. The polymer is elastomeric.