Metal Paste with Co-precursors for Low-Temperature Sintering
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Solution Overview
Problem
Conventional sintering processes for connecting pressure- and temperature-sensitive components in power electronics require high process temperatures and pressures, which can damage the components and are energy-intensive, and result in contact points with insufficient thermal and electrical conductivity.
Innovation Solution
A metal paste with 75-90% metal particles coated with organic compounds, 0.1-12% metal precursors, 6-20% solvent, and 0.1-15% sintering aids such as salts, esters, or carbonyl complexes is used, allowing for sintering at temperatures below 200°C, reducing porosity and enhancing conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sintering processes are used to connect components, then stable connections are achieved, but high process temperatures and pressures are required which can damage pressure- and temperature-sensitive components
Solution Approach 1:
The patent changes the chemical composition parameters of the metal paste by incorporating metal precursors that decompose at low temperatures to form metallic silver. This allows the sintering process to proceed at temperatures below 200°C instead of conventional high temperatures, resolving the contradiction between connection stability and temperature sensitivity of components.
Solution Approach 2:
The patent introduces metal precursors as intermediary substances that facilitate the sintering process. These precursors decompose to form metallic silver in situ, acting as a mediator that enables low-temperature sintering and stable connection formation simultaneously, avoiding direct thermal damage to sensitive components.
2Reliability
If conventional sintering processes are used to connect components, then stable connections are achieved, but high process pressures are required which can damage pressure- and temperature-sensitive components
Solution Approach 1:
The patent changes the physical and chemical parameters of the sintering process by using metal precursors that decompose to form metallic silver. This chemical transformation enables the formation of stable connections at reduced pressures below 3 bar, eliminating the need for high process pressures that would damage sensitive components.
3Use of energy by stationary object
If process temperature is reduced to below 200°C, then energy consumption is reduced and component damage is minimized, but contact points may have insufficient thermal and electrical conductivity
Solution Approach 1:
The patent uses metal precursors as intermediaries that decompose to form metallic silver particles during low-temperature sintering. These freshly formed metallic particles fill the contact points between components, ensuring high electrical and thermal conductivity is achieved even at reduced temperatures below 200°C, thus resolving the contradiction between energy efficiency and conductivity.
Solution Approach 2:
The patent creates a composite structure in the metal paste containing both metal particles and metal precursors. The precursors decompose to form additional metallic silver in situ, creating a composite material system that maintains high conductivity at low temperatures, resolving the contradiction between reduced energy consumption and sufficient electrical/thermal conductivity.
4Reliability
If metal particles are coated with organic compounds, then oxidation is prevented, but sintering temperature reduction becomes more challenging
Solution Approach 1:
The patent introduces metal precursors as intermediary substances that decompose at low temperatures to form metallic silver. These precursors act as mediators that enable the removal of organic coatings and reduction of metal oxides at temperatures below 200°C, resolving the contradiction between maintaining oxidation protection and achieving low-temperature sintering.
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 method enables stable, low-porosity, and highly conductive contact points between components, reducing the risk of damage and energy consumption while maintaining high electrical and thermal conductivity.
Implementation Method 1
a metal paste (A) contains 75 - 90 percent by weight of at least one metal which is in the form of particles which have a coating which contains at least one organic compound (B) 0.1-12% by weight of at least one metal precursor
Implementation Method 2
The carbon monoxide released during sintering is a reducing agent and as such is capable of reducing the metal oxide present on the surface of the metal particles
Implementation Method 3
the sandwich arrangement is sintered, characterized in that the metal paste (A) contains
Data Source
AI summary
The present invention relates to a sintering method which allows joining components in a stable manner, wherein the process temperature is below 200 ?C and stable contact points occur which have a low porosity and a high electrical and thermal conductivity. The invention relates to a method for joining components, in which (a) a sandwich arrangement is provided, which comprises at least (a1) a component (1), (a2) a component (2) and (a3) a metal paste situated between component (1) and component (2), and in which (b) the sandwich arrangement is sintered. The invention is characterized in that the metal paste comprises (A) 75-90 % by weight of at least one metal, which is present in the form of particles having a coating, containing at least one organic compound; (B) 0-12 % by weight of at least one metal precursor; (C) 6-20 % by weight of at least one solvent; and (D) 0.1-15 % by weight of at least one auxiliary sintering agent which is selected from the group consisting of (i) salts of organic acids, the organic acids having 1-4 carbon atoms, (ii) esters of organic acids, the organic acids having 1-4 carbon atoms, and (iii) carbonyl complexes.