Reversibly Adhesive Thermal Interface Material for Reworkable Electronics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal interface materials face issues such as increased interfacial resistance due to voids, fragility, delamination, and non-reworkability, which hinder effective heat dissipation and component recovery in high-performance electronics.
Innovation Solution
A thermally-reversible adhesive combined with a thermally conductive and electrically non-conductive filler, utilizing a polymer and cross-linking agent that undergo a reversible cross-linking reaction, allowing for efficient heat transfer and reworkability without damaging components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional conductive adhesives are used to provide thermal interface, then thermal conductivity is improved, but reworkability deteriorates (cannot be removed or reworked)
Solution Approach 1:
The adhesive's bond strength is changed as a function of temperature through reversible cross-linking chemistry. At room temperature, the adhesive maintains strong bonding for thermal conduction. At elevated temperatures (200-400°C), the cross-links reversibly break, reducing bond strength to enable rework. This parameter change resolves the contradiction by making the adhesive temporarily weak only when heated, not during normal operation.
Solution Approach 2:
The adhesive exhibits periodic bonding and debonding behavior based on temperature cycles. During normal operation, the adhesive remains bonded. During rework, heating temporarily breaks the bonds, allowing removal. After cooling, the bonds reform. This periodic action enables both strong thermal interface during use and ease of rework when needed.
2Temperature
If thermally conductive materials are used to dissipate heat, then heat dissipation efficiency is improved, but interfacial resistance increases due to voids and delamination
Solution Approach 1:
The adhesive's mechanical properties (modulus, compliance) are changed as a function of temperature and curing state. The reversible cross-linking allows the adhesive to be compliant during curing to fill voids, then maintains stable bonding at operating temperatures. This eliminates delamination and maintains low interfacial resistance, resolving the contradiction between heat dissipation and contact stability.
Solution Approach 2:
The adhesive forms a composite structure with the substrate through reversible cross-linking, creating a stable thermal interface. The composite nature ensures good adhesion and eliminates voids, maintaining low interfacial resistance while providing efficient heat dissipation path.
3Temperature
If pre-cut phase change material films are used to provide thermal interface, then thermal impedance is reduced, but structural integrity deteriorates (fragile, require fasteners)
Solution Approach 1:
The adhesive transitions from a uncured state (easy to apply) to a cross-linked state (structurally strong) through temperature-controlled reversible cross-linking. This allows the material to provide both low thermal impedance and high structural integrity, eliminating the need for fasteners while maintaining strength.
4Strength
If high modulus adhesive materials are used to bond components, then bonding strength is improved, but interface integrity deteriorates (causes delamination due to intrinsic stress)
Solution Approach 1:
The adhesive's modulus is changed as a function of temperature through reversible cross-linking. At curing temperature, the adhesive is compliant to accommodate thermal expansion differences. At operating temperature, the cross-links provide strong bonding without excessive stress. This resolves the contradiction by making the adhesive temporarily compliant only during curing, not during operation.
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 provides stable interfacial contact resistance, efficient heat dissipation, and the ability to rework thermal interface materials, enabling recovery and reuse of high-cost components while maintaining electrical insulation.
Implementation Method 1
a polymer containing a plurality of a first functional group; and a cross-linking agent containing a plurality of a second functional group, wherein the first functional group and the second functional group are complementary reactants to a reversible cross-linking reaction
Implementation Method 2
a thermally conductive and electrically non-conductive filler... effective to provide a thermal conductivity of 0.2 W/m-K or more
Data Source
AI summary
The present invention is directed to a reversibly adhesive thermal interface material for electronic components and methods of making and using the same. More particularly, embodiments of the invention provide thermal interface materials that include a thermally-reversible adhesive, and a thermally conductive and electrically non-conductive filler, where the thermal interface material is characterized by a thermal conductivity of 0.2 W/m-K or more and an electrical resistivity of 9×1011 ohm-cm or more.