Silver Compound Starter Material for Low-Temperature Sintering

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Solution Overview

Problem

Existing sintered connection technologies face challenges in achieving reliable and high-conductivity connections at elevated temperatures without using lead-containing solders, which are environmentally restricted, and require high processing temperatures that can damage temperature-sensitive components.

Innovation Solution

A starting material comprising silver carbonate, silver lactate, or silver stearate with a reducing agent coating, allowing for low-temperature sintering and forming a homogeneous sintered compound with high thermal and electrical conductivity, using a process that converts metal compounds to elemental silver efficiently at temperatures below the sintering point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sintering processes are used to achieve high conductivity, then electrical and thermal conductivity is improved, but processing complexity and temperature requirements increase

Engineering Contradiction:
Improveelectrical and thermal conductivityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The organic coating on the metal compound particles contains reducing agents that automatically reduce the metal compounds to metallic form during heating, eliminating the need for separate reduction steps or complex processing equipment. The system self-manages the chemical transformation required for high conductivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical sintering systems with high pressure and temperature requirements by using chemical reduction mechanisms. The organic coating's reducing agents chemically transform the metal compounds into conductive metallic structures through thermal activation alone, simplifying the overall processing system

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

2Temperature

If metal compounds are used as starting material for low-temperature sintering, then processing temperature is reduced, but conversion efficiency and homogeneity of the sintered compound becomes challenging

Engineering Contradiction:
Improveprocessing temperatureVSAvoidconversion efficiency and homogeneity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The organic coating is applied locally on the surface of each metal compound particle, creating a localized reducing agent reservoir exactly where needed. This ensures uniform and efficient reduction across all particles during heating, achieving homogeneous metallic conversion throughout the sintered compound without requiring excessive temperature or complex processing

Inventive Principle:
Principle #3Local quality

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 enables the production of sintered connections with high thermal and electrical conductivity, achieving up to 99% conversion of metal compounds to elemental silver, reducing processing temperatures, and minimizing gaseous by-products, while avoiding the use of lead and high temperatures that could damage components.

Implementation Method 1

the silver compound is reduced to elemental silver, forming the sintered compound

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

sintered connections with high thermal and electrical conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

sintered connections with high thermal and electrical conductivity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2629911B1Starter material for a sintering compound and method for producing said sintering compound
Publication Date: 2020.07.22 ROBERT BOSCH GMBH
  • EP2629911B1 patent drawingFigure 1~2a
  • EP2629911B1 patent drawingFigure 2b~3

AI summary

The invention relates to a starter material for a sintering compound, said starter material comprising first particles of at least one metal having a first coating which is applied to the first particles and consists of an organic material, and second particles which contain an organic metal compound and/or a precious metal oxide, the organic metal compound and/or the precious metal oxide being converted during heat treatment of the starter material into the fundamental elemental metal and/or precious metal. The invention is characterized in that the second particles have a core of at least one metal and a second coating which is applied to the core and contains the organic metal compound and/or precious metal oxide. Furthermore, the first coating contains a reducing agent by means of which the organic metal compound and/or the precious metal oxide is/are reduced to the elemental metal and/or precious metal at a temperature below the sintering temperature of the elemental metal and/or precious metal.