Heat-Conductive Sheet Composition for Adhesion and Breakdown Voltage

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional thermal conductive sheets face challenges in achieving both high heat dissipation capability and breakdown voltage due to insufficient adhesion when the surface of the adherend is not flat, primarily because of high inorganic filler content reducing the thermosetting resin content, leading to poor adhesion and increased thermal resistance.

Innovation Solution

A thermal conductive sheet with a resin layer composed of a thermosetting resin, a curing agent, and an inorganic filler, where the curing agent is a benzoxazine derivative, enhances adhesion and maintains a high content of inorganic filler, ensuring improved heat dissipation and breakdown voltage even on non-flat surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the content of inorganic filler in the resin layer is increased to improve thermal conductive properties, then heat dissipation capability is improved, but the content of thermosetting resin decreases leading to insufficient adhesion to the heat sink surface

Engineering Contradiction:
Improveheat dissipation capabilityVSAvoidadhesion to adherend
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the resin layer by specifying a particular thermosetting resin (epoxy resin with specific molecular weight range of 1,000-10,000) and curing agent combination, along with controlled filler content (30-80 vol%), to achieve optimal balance between adhesion and thermal conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resin layer combining organic thermosetting resin matrix with inorganic filler particles, where the resin content is optimized to provide both adequate adhesion to non-flat surfaces and sufficient thermal conduction through the filler network

Inventive Principle:
Principle #40Composite materials

2Temperature

If the content of inorganic filler in the resin layer is increased to improve thermal conductive properties, then heat dissipation capability is improved, but the break down voltage decreases

Engineering Contradiction:
Improveheat dissipation capabilityVSAvoidbreak down voltage
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent optimizes the resin composition parameters including thermosetting resin type (epoxy resin), curing agent selection, and filler content ratio to achieve a balance where thermal conductivity is enhanced while maintaining adequate electrical insulation properties through sufficient resin matrix continuity

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the surface of the adherend is not sufficiently flat, then manufacturing flexibility is improved, but the adhesion between the adherend and resin layer becomes insufficient

Engineering Contradiction:
Improveadaptability to non-flat surfacesVSAvoidadhesion to adherend
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent modifies the resin composition by selecting specific epoxy resin molecular weights (1,000-10,000) and adjusting the resin-to-filler ratio to create a material with optimal viscosity and adhesion properties that can conform to and bond with non-flat surfaces while maintaining structural integrity

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 sheet achieves enhanced adhesion, improved heat dissipation capability, and increased breakdown voltage by using a benzoxazine derivative as the curing agent, allowing for effective heat transfer and reduced thermal resistance.

Implementation Method 1

a resin layer composed of a resin composition that includes a thermosetting resin, a curing agent, and an inorganic filler, the curing agent including a benzoxazine derivative

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

a thermal conductive sheet for transferring the heat to the heat dissipation surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4166593B1Heat-conductive sheet and semiconductor module including said heat-conductive sheet
Publication Date: 2025.08.27 NITTO SHINKO KK
  • EP4166593B1 patent drawingFigure 1
  • EP4166593B1 patent drawingFigure 2
  • EP4166593B1 patent drawingFigure 3~4

AI summary

A thermal conductive sheet according to the present invention is a thermal conductive sheet including a resin layer composed of a resin composition that includes a thermosetting resin, a specific curing agent, and an inorganic filler.