Sinter Paste with Partially Oxidized Metal Particles for Low-Temperature Joining

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Solution Overview

Problem

Conventional sintering pastes face challenges in achieving improved sinterability, especially at low process pressures and temperatures, resulting in insufficient adhesion and thermal/electrical conductivity in connecting pressure and temperature-sensitive components like LEDs or thin silicon chips.

Innovation Solution

A sinterable mixture comprising metal particles and an organic compound with a specific molar ratio of carbon to oxygen, along with cellulose, which enhances sinterability and adhesion by promoting diffusion and reducing porosity, allowing for sintering under milder conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional sintering pastes are used, then components can be connected, but sinterability is insufficient especially at low process pressures and temperatures

Engineering Contradiction:

Improvesintering temperatureVSAvoidsinterability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the sintering paste by incorporating metal particles with specific oxide coatings and organic compounds with defined carbon-to-oxygen molar ratios. This compositional parameter change enables effective sintering at lower temperatures while maintaining reliable adhesion and conductivity properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite sintering paste system combining metal particles (silver, copper, aluminum, nickel) with specific oxide coatings and organic compounds. This composite material structure provides both the low-temperature sintering capability and the reliable adhesion/strength properties simultaneously

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional sintering pastes are used, then components can be connected, but adhesion of contacts is insufficient

Engineering Contradiction:

Improveadhesion of contactsVSAvoidsintering process conditions

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical parameters of the sintering paste by incorporating metal particles with controlled oxide coatings and organic compounds with specific carbon-to-oxygen ratios. These parameter changes enable strong adhesion to form under milder manufacturing conditions with lower pressure and temperature requirements

Inventive Principle:

Principle #35Parameter changes

3Reliability

If adhesive technology is used to connect components, then pressure and temperature sensitive components can be connected, but thermal conductivity and electrical conductivity are insufficient

Engineering Contradiction:

Improveconnection stabilityVSAvoidthermal conductivity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces adhesive technology with a sintering-based connection method. This substitution transitions from a mechanical/chemical bonding system to a metallurgical bonding system that inherently provides superior thermal and electrical conductivity while maintaining connection stability for pressure and temperature sensitive components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Loss of energy

If conventional sintering pastes are used, then components can be connected, but porosity remains high reducing conductivity

Engineering Contradiction:

Improveelectrical and thermal conductivityVSAvoiddiffusivity of mixture

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating specific organic compounds with defined carbon-to-oxygen molar ratios and metal particles with controlled oxide coatings. These parameter changes promote better diffusion during sintering, reducing porosity and improving electrical and thermal conductivity of the final connection

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 mixture enables stable, thermally and electrically conductive connections with improved sinterability, enabling energy-efficient connections of components at lower temperatures and pressures, enhancing the reliability and performance of electronic components.

Implementation Method 1

improved sinterability, particularly when applied to a copper surface... improved diffusivity

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

thermally conductive connections with improved sinterability

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

electrically conductive connections with improved sinterability

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2799164B1Improved sinter paste with partially oxidised metal particles

Publication Date: 2018.12.19 HERAEUS DEUTSCHLAND GMBH & CO KG

Figure 1~2

AI summary

The present invention relates to a sinterable mixture and a method for joining components in which this mixture is used. The invention further relates to a method for producing the sinterable mixture.