Thermal Bonding Material Using Metal Fine Particles and Polyols

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Solution Overview

Problem

Existing methods for electronic component bonding, such as solder paste, require complex equipment and processes, are prone to impurities, and have issues with bonding strength and thermal expansion mismatch, leading to potential short circuits and spattering.

Innovation Solution

A thermal bonding material composed of metal fine particles dispersed in an organic compound dispersion medium with polyols, which can be melted or softened for patterning without specific apparatus, forming a sintering body with high bonding strength and low impurities, allowing for bonding between metal, semiconductor, and ceramic members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solder paste is used for bonding, then bonding between components and substrates can be achieved, but complex equipment (dispenser, screen printing) and processes are required

Engineering Contradiction:
Improvebonding reliabilityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical application system (dispenser, screen printing) with a thermal field system. The organic compound dispersion medium is heated to melt the metal fine particles and enable self-bonding, substituting mechanical patterning equipment with thermal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state parameters of the bonding material. By controlling temperature to melt the organic compound dispersion medium (melting point 30-150°C), the metal fine particles become mobile and can self-organize into patterns without mechanical intervention.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If solder paste is used for bonding, then bonding can be achieved, but impurities remain in the bonded structure

Engineering Contradiction:
Improvebonding reliabilityVSAvoidimpurity content
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful flux components from the bonding process. The organic compound dispersion medium is designed to decompose and evaporate completely during thermal processing, leaving only pure metal bonds without flux residues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The organic compound dispersion medium serves as a temporary carrier that is discarded through controlled decomposition and evaporation, leaving behind the desired metal bonding structure free of impurities.

Inventive Principle:
Principle #34Discarding and recovering

3Strength

If solder paste is used for bonding, then bonding can be achieved, but bonding strength is insufficient and spattering occurs

Engineering Contradiction:
Improvebonding strengthVSAvoidspattering
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite material system consisting of metal fine particles dispersed in an organic compound dispersion medium. This composite structure allows controlled melting and sintering, achieving strong bonds without the spattering problems of conventional solder paste.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes phase transitions of the organic compound dispersion medium (solid→liquid→gas) to control the bonding process. The material melts at 30-150°C to enable particle mobility, then evaporates to leave strong metal bonds, avoiding the violent boiling that causes spattering.

Inventive Principle:
Principle #36Phase transitions

4Reliability

If solder paste is used for bonding, then bonding can be achieved, but thermal expansion mismatch causes short circuits

Engineering Contradiction:
Improvebonding reliabilityVSAvoidthermal expansion mismatch
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the bonding temperature parameter to a lower range (30-150°C) that matches the thermal expansion characteristics of electronic components and substrates, reducing thermal stress and preventing short circuits from expansion mismatch.

Inventive Principle:
Principle #35Parameter changes

5Ease of manufacture

If solder paste is stored, then bonding material is available, but storage requires sealed or cooled conditions

Engineering Contradiction:
Improvematerial availabilityVSAvoidstorage conditions
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the storage temperature parameter to ambient conditions by using an organic compound dispersion medium with a melting point of 30-150°C. The material remains solid at room temperature for easy storage, then melts during bonding without requiring refrigeration or special sealing.

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 material simplifies the bonding process, reduces impurities, enhances bonding strength, and improves electrical conductivity, while accommodating different thermal expansion rates, and allows for easy storage and handling without specialized equipment.

Implementation Method 1

melted or softened through heating at a temperature higher than 30 degrees C.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

melted or softened through heating at a temperature higher than 30 degrees C.

Methodology Applied
Scientific EffectPhase Change: Phase Change

Implementation Method 3

the metal fine particles (P) have sinterability

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS9221130B2Material for thermal bonding, coating material for thermal bonding, coating, and electronic component bonding method
Publication Date: 2015.12.29 FURUKAWA ELECTRIC CO LTD

AI summary

A material is for thermal bonding by metal fine particle sintering mediated by a metal sintered film, such that shorts do not occur readily between bonded sections, and bonding strength is higher than that achieved by plating or sputtering. The material is obtained by dispersing metal fine particles in an organic compound dispersion medium that melts or softens through heating at a temperature higher than 30° C., and is interposed between metal members, semiconductor members or ceramic members. The material includes 60 wt % or more of the organic compound dispersion medium containing one or more types of a polyol having a melting point or softening point of 30° C. or higher and having two or more hydroxyl groups in the molecule, and 80 wt % or more of the metal fine particles that have an average particle size of primary particles ranging from 5 to 200 nm.