Viscoelastic Thermal Interface Compound Shear Dispensing

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Solution Overview

Problem

As electronic components become smaller and more densely packed, traditional methods of heat dissipation, such as air circulation, are insufficient, and existing thermal interface materials are messy, costly to apply, and require additional layers or clamping forces to ensure efficient heat transfer.

Innovation Solution

A viscoelastic compound comprising a particulate thermally and electrically conductive filler and a pre-cured silicone polymer gel is treated with a shear force to reduce its viscosity, making it dispensable and capable of filling gaps between electronic components for improved thermal and EMI shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional air circulation methods are used for heat dissipation, then the device structure remains simple, but the heat dissipation efficiency becomes insufficient for densely packed electronic components

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

A thermal interface compound is introduced as an intermediary material between the electronic component and heat dissipation member. This compound fills surface irregularities and eliminates air pockets, creating an efficient thermal pathway without requiring complex cooling systems. The compound acts as a mediator that enables effective heat transfer through the interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If silicone grease or wax is used as thermal interface material, then heat transfer efficiency improves, but the material becomes messy to apply and requires additional layers or clamping forces

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidapplication ease
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The invention changes the physical parameters of the thermal interface material by using a viscoelastic compound with temperature-dependent viscosity. At room temperature, the compound is viscous and self-supporting for easy handling and application. At operating temperatures, it softens to flow and conform to surface irregularities, eliminating the need for additional layers or clamping forces while maintaining heat transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a substrate or carrier is provided for the thermal interface material, then handling ease improves, but additional interface layers are introduced that may form air pockets

Engineering Contradiction:
Improvehandling easeVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The invention extracts and eliminates the substrate or carrier layer from the thermal interface system. The viscoelastic compound is applied directly between the component and heat dissipation member without requiring a supporting substrate. This removal of the intermediate carrier eliminates the additional interface layers that would otherwise trap air pockets and reduce heat transfer efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If hand application or lay-up by electronics assembler is used, then material placement flexibility improves, but manufacturing costs increase

Engineering Contradiction:
Improveapplication flexibilityVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The viscoelastic compound exhibits self-leveling and self-conforming properties due to its temperature-dependent viscosity. When applied, it automatically flows to fill surface irregularities and conform to the interface geometry without requiring manual manipulation or positioning by assemblers. This self-service characteristic enables both flexible placement and automated application processes, reducing labor costs while maintaining application flexibility.

Inventive Principle:
Principle #25Self-service

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 compound effectively transfers heat and shields against electromagnetic interference, eliminating the need for additional layers or clamping forces, while being easy to apply and cost-effective, with a long shelf-life and unlimited working time.

Implementation Method 1

a thermally-conductive, electrically-insulating material often is interposed between the heat sink and electronic component to fill in any surface irregularities and eliminate air pockets

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The present invention generally relates to methods, materials and devices for improved electromagnetic/radiofrequency interference (EMI/RFI) shielding and thermal management in packaging electronic circuits

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 3

a viscoelastic compound comprising a particulate thermally and electrically conductive filler and a pre-cured silicone polymer gel is treated with a shear force to reduce its viscosity

Methodology Applied
Scientific EffectViscoelastic flow: Viscoelasticity

Data Source

PatentEP1999529B1Dispensable cured resin
Publication Date: 2014.07.16 PARKER HANNIFIN CORP

AI summary

The present invention discloses methods, materials and devices for facilitating electromagnetic/radiofrequency interference (EMI/RFI) shielding and thermal management in packaging circuits. More specifically, a method of packaging integrated circuits with improved thermal and EMI management, a process of treating a compound for use as a thermal interface and/or an EMI shield, and an EMI shielding and thermal management apparatus. More specifically, the present invention divulges methods and apparatuses for adjusting viscosity of a thermally and/or electrically conductive (or thermally conductive and/or electrically insulative), form-in-place, fully cured compound thereby rendering the compound dispensable. Further, a process of treating a compound for use as a thermal interface or/and an EMI shield is disclosed. The compound is an admixture of a particulate filler component and a pre- cured gel component. The process includes applying a shearing force on the compound, thereby rendering the compound dispensable.