Multilayer Resin Sheet Adhesion and Thermal Conductivity

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Solution Overview

Problem

Existing thermally conductive resin compositions face challenges in achieving high thermal conductivity, adhesion strength, and insulating properties simultaneously, particularly with boron nitride fillers which exhibit low adhesion strength and difficulty in controlling resin flowability due to their scale-like shape and non-Newtonian fluid behavior.

Innovation Solution

A multilayer resin sheet is developed with a resin composition layer containing a thermosetting resin and a boron nitride filler, accompanied by an adhesive layer with specific surface roughness and thickness, enhancing adhesion and thermal conductivity by embedding the filler in the adhesive layer and optimizing the resin composition's filler content and particle size distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If boron nitride filler is used to achieve high thermal conductivity, then thermal conductivity is improved, but adhesion strength deteriorates due to the soft nature of boron nitride

Engineering Contradiction:
Improvethermal conductivityVSAvoidadhesion strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention uses a composite system consisting of boron nitride filler (for thermal conductivity) combined with specific thermosetting resins (epoxy resin, amine curing agent, and curing catalyst) to create a resin composition that achieves both high thermal conductivity and adequate adhesion strength. The composite structure allows the boron nitride particles to provide thermal pathways while the resin matrix provides binding and adhesion.

Inventive Principle:
Principle #40Composite materials

2Temperature

If boron nitride filler with scale-like shape is used to improve thermal conductivity, then thermal conductivity is improved, but resin flowability control deteriorates due to non-Newtonian fluid behavior

Engineering Contradiction:
Improvethermal conductivityVSAvoidresin flowability control
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention controls resin flowability by carefully adjusting the parameters of the resin composition system, including the types and amounts of epoxy resin, amine curing agent, and curing catalyst. By optimizing these compositional parameters, the patent achieves manageable viscosity and flow characteristics despite the presence of scale-like boron nitride particles that induce non-Newtonian behavior.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If high filler content is used to achieve high thermal conductivity, then thermal conductivity is improved, but insulating properties deteriorate

Engineering Contradiction:
Improvethermal conductivityVSAvoidinsulating properties
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention optimizes the filler content parameter within a specific range (40-85% by volume) to balance thermal conductivity and insulating properties. This parameter optimization ensures that sufficient boron nitride is present for thermal management while maintaining enough resin matrix to provide electrical insulation and prevent direct conductive pathways for electricity.

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 multilayer resin sheet achieves excellent thermal conductivity, adhesion strength, and insulating properties, improving dielectric breakdown strength and reducing the risk of exfoliation under thermal shock, while maintaining thermal conductivity post-curing.

Implementation Method 1

an adhesive layer that is disposed on at least one surface of the resin composition layer, the adhesive layer having an arithmetic average surface roughness Ra of 1.5 μm or less at a surface that does not face the resin composition layer

Methodology Applied
Scientific EffectMechanical interlocking:

Implementation Method 2

a resin composition layer that comprises a thermosetting resin and a filler... the filler comprises a boron nitride filler... achieve a thermal conductivity of from 6 to 11 W/mK as measured by temperature wave analysis

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a cured multilayer resin sheet and a method for producing the same... a resin composition layer that comprises a thermosetting resin... a cured product of a composite system of a typical bisphenol A epoxy resin and an alumina filler

Methodology Applied
Scientific EffectCuring:

Implementation Method 4

improving dielectric breakdown strength and reducing the risk of exfoliation under thermal shock

Methodology Applied
Scientific EffectThermal shock resistance: Thermal Shock

Data Source

PatentEP2692526B1Multilayer resin sheet, resin sheet laminate, cured multilayer resin sheet and method for producing same, multilayer resin sheet with metal foil, and semiconductor device
Publication Date: 2020.10.28 RESONAC CORP
  • EP2692526B1 patent drawingFigure 1~2
  • EP2692526B1 patent drawingFigure 3(a)~3(c)
  • EP2692526B1 patent drawingFigure 4(a)~5(b)

AI summary

The invention provides a multilayer resin sheet that includes: a resin composition layer that includes a thermosetting resin and a filler; and an adhesive layer that is disposed on at least one surface of the resin composition layer, the adhesive layer having an arithmetic average surface roughness Ra of 1.5 µm or less at a surface that does not face the resin composition layer.