Nitride Composite Sheet Surface Control for Uniform Heat Dissipation

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Solution Overview

Problem

Conventional composite sheets used in laminates for electronic components like LED lighting and in-vehicle power modules exhibit variations in heat dissipation properties, leading to inconsistent thermal conductivity when bonded with metal substrates.

Innovation Solution

A composite sheet with a nitride sintered body having a porous structure and a semi-cured thermosetting resin composition, where the principal surface has a line roughness Rz of 10 µm or less, is used, along with a method involving wire saw cutting to produce the sheet, ensuring uniform resin layer thickness and improved adhesiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional composite sheet with larger surface irregularities is used, then the manufacturing process is simpler, but the resin layer thickness varies at the interface with the metal substrate, causing variations in thermal conductivity

Engineering Contradiction:
Improvesurface roughnessVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by controlling the line roughness Rz to 10 μm or less through specific wire saw cutting conditions (wire reciprocating linear speed of 155 to 1000 mm/min and table moving speed of 4 mm/min). This parameter control resolves the contradiction by achieving smooth surfaces that ensure uniform resin layer thickness and consistent thermal conductivity, while the wire saw cutting method remains a standard manufacturing process.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a composite sheet with smoother surface is used, then the resin layer thickness becomes more uniform improving heat dissipation, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveresin layer thickness uniformityVSAvoidcutting process parameters
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent resolves this contradiction by optimizing cutting parameters (wire reciprocating linear speed of 155 to 1000 mm/min and table moving speed of 4 mm/min) to achieve line roughness Rz of 10 μm or less. This creates uniform resin layer thickness at the interface, ensuring consistent heat dissipation properties without requiring complex additional manufacturing steps.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional composite sheets are used, then the manufacturing process is straightforward, but variations in thermal conductivity occur at different positions of the laminate

Engineering Contradiction:
Improvethermal conductivity uniformityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent addresses this contradiction by controlling the line roughness Rz to 10 μm or less through optimized wire saw cutting parameters. This ensures uniform resin layer thickness across the entire laminate surface, eliminating positional variations in thermal conductivity while maintaining production efficiency through a streamlined cutting process.

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 solution results in a laminate with enhanced heat dissipation properties and reduced variations in thermal conductivity across the interface, providing consistent and improved heat management.

Implementation Method 1

The composite sheet comprises the semi-cured product of the thermosetting composition and thus may adhere to an adherend

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

there is a problem of efficient dissipation of heat generated during use... a composite (heat dissipation member) composed of a resin and ceramics such as boron nitride

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4044220B1Composite sheet and method for manufacturing same, and laminate and method for manufacturing same
Publication Date: 2024.02.21 DENKA CO LTD
  • EP4044220B1 patent drawingFigure 1
  • EP4044220B1 patent drawingFigure 2
  • EP4044220B1 patent drawingFigure 3

AI summary

One aspect of the present disclosure provides a composite sheet including: a nitride sintered body having a porous structure; and a semi-cured product of a thermosetting resin composition impregnated into the nitride sintered body, at least one principal surface of the composite sheet having line roughness Rz, specified in JIS B0601: 2013, of 10 µm or less.