Metal Paste Sintering for Low-Temperature Component Joining

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Solution Overview

Problem

Conventional sintering processes for connecting pressure- and temperature-sensitive components in power and consumer electronics require high pressure and temperature, which can damage the components, and result in contact points with insufficient thermal and electrical conductivity.

Innovation Solution

A metal paste with a specific composition, including 75-90% metal particles coated with organic compounds, 0-12% metal precursors, 6-20% organic solvents, and 0-10% sintering aids, is used in a sintering process at 200-250°C without pressure to form low-porosity contact points with high electrical and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sintering processes are used to connect components, then stable connection is achieved, but high process pressure and temperature are required which can damage pressure- and temperature-sensitive components

Engineering Contradiction:
Improveconnection stabilityVSAvoidcomponent damage from high pressure and temperature
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the process parameters by using a specifically formulated metal paste containing organic solvents and sintering aids that enable sintering at reduced temperatures (200-250°C) and without high pressure, thereby achieving stable connections without damaging sensitive components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The metal paste acts as an intermediary material between components, containing organic solvents and sintering aids that facilitate low-temperature sintering. The paste composition mediates the sintering process to occur under gentler conditions that protect pressure- and temperature-sensitive components

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

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

Engineering Contradiction:
Improveprotection of sensitive componentsVSAvoidthermal and electrical conductivity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention uses a composite metal paste material containing metal particles (75-90 wt%), organic solvents (6-20 wt%), and sintering aids (0.1-15 wt%). This composite formulation combines the benefits of low-processing temperatures with high thermal and electrical conductivity, eliminating the conductivity deficiency of pure adhesive materials

Inventive Principle:
Principle #40Composite materials

3Reliability

If high process pressure is applied during sintering, then stable connection is achieved, but pressure-sensitive components are damaged

Engineering Contradiction:
Improveconnection stabilityVSAvoidcomponent damage from high pressure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the pressure parameter by formulating a metal paste that enables pressureless or low-pressure sintering. The organic solvents and sintering aids in the paste allow densification and bonding to occur without applying high mechanical pressure, thus protecting pressure-sensitive components while maintaining connection stability

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 process enables a strong, pressureless connection of components with improved thermal and electrical conductivity, suitable for fragile or mechanically sensitive components, without causing damage during the sintering process.

Implementation Method 1

the sandwich arrangement is sintered, the metal paste consisting of (A) 75 to 90% by weight of at least one metal which is in the form of particles

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

6 to 20% by weight of a mixture of at least two organic solvents

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2942129B1Metal paste and its use in joining components
Publication Date: 2017.07.05 HERAEUS DEUTSCHLAND GMBH & CO KG

AI summary

Metal paste containing (A) 75 to 90 wt.% of at least one metal in the form of particles having a coating containing at least one organic compound, (B) 0 to 12 wt.% of at least one metal precursor, (C) 6 to 20 wt.% of a mixture of at least two organic solvents and (D) 0 to 10 wt.% of at least one sintering aid, characterized in that the solvent mixture (C) consists of at least 30 to 60 wt.% of at least one 1-hydroxyalkane with 16-20 carbon atoms unsubstituted except for a methyl substitution at the penultimate carbon atom.