Particle-Based Connecting Material for Crack-Resistant Bond Joints

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Solution Overview

Problem

Conventional connecting materials fail to adequately suppress cracking and peeling during thermal cycles in semiconductor devices, and they also struggle to maintain uniform thickness and high connection strength between connected members.

Innovation Solution

The use of particles with specific size, compression modulus, and diameter variation characteristics, along with a thermal decomposition temperature of 200°C or more, to form a connection part that suppresses cracking and peeling during thermal cycles and maintains uniform thickness and high connection strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional connecting materials are used, then the connection part can be formed, but cracking and peeling occur during thermal cycles

Engineering Contradiction:
Improveconnection reliabilityVSAvoidconnection strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite connecting material consisting of metal particles (such as Ag, Cu, Al, or their alloys) combined with glass particles or ceramic particles. This composite structure combines the high electrical conductivity and ductility of metals with the high melting point, chemical stability, and crack resistance of glass or ceramic, thereby preventing cracking and peeling during thermal cycles while maintaining connection reliability and strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for the connecting material: metal particle diameter of 1-10 μm, glass particle diameter of 5-20 μm, metal content of 70-90 wt%, and glass content of 10-30 wt%. By optimizing these parameters, the material achieves balanced properties that prevent thermal cycle damage while maintaining strong connections

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional connecting materials are used, then connection is achieved, but variation in thickness of connection part is large

Engineering Contradiction:
Improvethickness uniformityVSAvoiddistance control accuracy
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent controls the average diameter of metal particles within 1-10 μm and glass particles within 5-20 μm, with specific size distributions. This precise parameter control ensures uniform flow and distribution during connection, reducing thickness variation and improving manufacturing precision without complicating the manufacturing process

Inventive Principle:
Principle #35Parameter changes

3Temperature

If metal particles with small diameter (≤100 nm) are used, then sintering temperature decreases, but connection strength and heat resistance are insufficient

Engineering Contradiction:
Improvesintering temperatureVSAvoidconnection strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent combines metal particles (1-10 μm) with glass particles (5-20 μm) in specific proportions. The glass particles act as a matrix that binds the metal particles together, providing structural strength and heat resistance while the metal particles provide conductivity. This composite approach allows lower sintering temperatures than bulk metal while achieving sufficient connection strength through the synergistic effect of both materials

Inventive Principle:
Principle #40Composite materials

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 proposed particles effectively prevent cracking and peeling during thermal cycles, ensuring uniform thickness and increased connection strength in semiconductor devices.

Implementation Method 1

by sintering the metal particles to one another is known. In this connection method, metal particles after connection change to a bulk metal, and at the same time, connection by metal bonding is obtained in the connection interface

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

the surfaces of which are coated with an organic substance, as a connecting material, the connection is performed by decomposing the organic substance by heating, and by sintering the metal particles to one another

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentEP3378914B1Connecting material and connection structure
Publication Date: 2025.08.06 SEKISUI CHEMICAL CO LTD
  • EP3378914B1 patent drawingFigure 1~2
  • EP3378914B1 patent drawingFigure 3~4
  • EP3378914B1 patent drawing

AI summary

Particles that can suppress the occurrence of cracking or peeling during a thermal cycle in a connection part that connects two members to be connected, further can suppress the variation in thickness in the connection part, and can increase the connection strength are provided. The particles according to the present invention are particles used to obtain a connecting material for forming a connection part that connects two members to be connected, and the particles are used for forming the connection part such that thickness of the connection part after connection is twice or less the average particle diameter of the particles before connection, or the particles have an average particle diameter of 1 µm or more and 300 µm or less, the particles have a 10% K value of 30 N/mm2 or more and 3000 N/mm2 or less, and the particles have a particle diameter CV value of 10% or less.