Carbon-Polymer TIM Bonding for Flux-Resistant Heat Dissipation

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Solution Overview

Problem

Current thermal interface materials (TIMs) face challenges in providing improved thermal performance and resistance to flux used in solder TIM (STIM) processing, particularly due to the inhibition of polymer TIM cure by flux and thermal performance limitations.

Innovation Solution

A composite thermal interface material is developed, featuring polymer chains chemically bonded to fill particles with hexagonal lattices of carbon atoms, such as graphene sheets and carbon nanotubes, which form covalent bonds during cure, enhancing wetting and thermal conductivity, and being impervious to flux in STIM processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polymer TIM is used to improve thermal performance, then thermal conductivity is enhanced, but cure is inhibited by flux in STIM processing

Engineering Contradiction:

Improvethermal conductivityVSAvoidcure inhibition

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent converts the harmful effect of flux (which normally inhibits polymer cure) into a beneficial outcome by using flux-resistant polymer formulations and processing methods. The polymer TIM is specifically designed to cure in the presence of flux, transforming the previously harmful interaction into a compatible processing condition that enables both STIM and PTIM benefits.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent employs composite material formulations combining polymer matrices with carbon-based fillers (such as carbon nanotubes, graphene, or graphite particles) to achieve high thermal conductivity while maintaining flux resistance. This composite approach allows the TIM to simultaneously provide superior thermal performance and compatibility with STIM processing conditions.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If traditional PTIM is used, then ease of application is maintained, but thermal performance is limited

Engineering Contradiction:

Improveease of applicationVSAvoidthermal performance

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The patent incorporates high thermal conductivity fillers (carbon nanotubes, graphene, graphite) into the polymer TIM matrix to dramatically enhance thermal performance while preserving the material's ease of application characteristics. The composite structure maintains the polymer's conformability and applicability to complex surfaces while providing superior heat transfer capabilities.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the polymer TIM, including viscosity, particle size distribution, and filler concentration, to optimize both thermal performance and ease of application. By carefully controlling these parameters, the TIM achieves high thermal conductivity while remaining easy to apply and conform to various surface geometries.

Inventive Principle:

Principle #35Parameter changes

3Strength

If STIM processing is used, then strong adhesion is achieved, but flux inhibits polymer TIM cure

Engineering Contradiction:

ImproveadhesionVSAvoidcure inhibition

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent transforms the harmful interaction between flux and polymer cure into a beneficial process by developing flux-resistant polymer formulations. These formulations are specifically designed to cure effectively in the presence of flux, enabling the combination of STIM's strong adhesion benefits with polymer TIM's thermal performance advantages without cure inhibition.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent adjusts chemical parameters of the polymer system, including crosslinking density, functional group composition, and curing mechanism, to achieve flux resistance while maintaining strong adhesion. By optimizing these parameters, the TIM cures reliably in the presence of flux and forms strong bonds to both die and heat sink surfaces.

Inventive Principle:

Principle #35Parameter changes

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 composite TIM achieves improved thermal conductivity, adhesion, and resistance to flux, enabling effective heat dissipation and enhanced performance in microelectronic devices, particularly in multi-chip assemblies and systems requiring high thermal management.

Implementation Method 1

a composite material to conduct heat from the microelectronic die... fill particles comprising a hexagonal lattice of carbon atoms

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

polymer chains chemically bonded to fill particles... form covalent bonds during cure

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS11881440B2Carbon based polymer thermal interface materials with polymer chain to carbon based fill particle bonds

Publication Date: 2024.01.23 INTEL CORP

AI summary

Microelectronic devices, assemblies, and systems include a microelectronic die and composite material to conduct heat from the microelectronic die such that the composite material includes polymer chains chemically bonded to fill particles having a hexagonal lattice of carbon atoms such as graphene sheet fill particles and/or carbon nanotube fill particles.