Coated Silver Sintering Paste for Pretreatment-Free Copper Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing silver sintering methods face challenges in forming reliable connections on non-precious metal contact surfaces, such as copper, especially at low sintering temperatures without mechanical pressure, and often require pretreatment of the metal surfaces.
Innovation Solution
A silver sintering method using a silver sintering preparation comprising 70-95 wt.% coated silver particles with silver acetylacetonate or silver salts thermally decomposable above 160°C, applied as a paste or preform, which forms reliable connections between electronic components without pretreatment and mechanical pressure, even at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silver sintering methods are used on non-precious metal surfaces, then connection reliability is improved, but surface pretreatment is required which increases process complexity
Solution Approach 1:
The invention extracts and removes the surface pretreatment step from the conventional sintering process by using silver particles with specialized coatings that enable direct sintering on non-precious metal surfaces without requiring oxidation or other surface modifications
Solution Approach 2:
The invention changes the surface properties of silver particles through specialized coatings (silver acetylacetonate and long-chain silver salts) that modify how the particles interact with non-precious metal surfaces, enabling reliable bonding without pretreatment
2Use of energy by stationary object
If low sintering temperatures are used without mechanical pressure, then energy consumption is reduced, but connection reliability deteriorates on non-precious metal surfaces
Solution Approach 1:
The invention changes the chemical composition and surface properties of the silver particles through specialized coatings, which lowers the sintering temperature requirement while maintaining connection reliability on non-precious metal surfaces without mechanical pressure
Solution Approach 2:
The invention uses composite silver particles with core-shell structure (metallic silver core with organic coating shell) that combine the benefits of low-temperature sintering capability with reliable bonding to non-precious metal surfaces
3Ease of manufacture
If silver particles with simple coatings are used, then manufacturing cost is reduced, but sintering temperature must be increased above 160°C
Solution Approach 1:
The invention changes the coating composition to include silver acetylacetonate and long-chain silver salts (caprylate, caprate, laurate) that decompose at temperatures above 160°C, enabling controlled sintering at moderate temperatures while maintaining manufacturing efficiency
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 reliable connections on non-precious metal surfaces like copper at room and elevated temperatures without mechanical pressure, ensuring strong bonding and eliminating the need for surface pretreatment, thus enhancing the reliability and efficiency of electronic component joining.
Implementation Method 1
wherein the at least one silver salt is thermally decomposable at >160° C.
Data Source
AI summary
A silver sintering preparation in the form of a silver sintering paste comprising 70 to 95 wt.-% of coated silver particles (A) and 5 to 30 wt.-% of organic solvent (B) or in the form of a silver sintering preform comprising 74.5 to 100 wt.-% of coated silver particles (A) and 0 to 0.5 wt.-% of organic solvent (B), wherein the coating of the coated silver particles (A) comprises silver acetylacetonate (silver 2,4-pentanedionate) and/or at least one silver salt of the formula CnH2n+1COOAg with n being an integer in the range of 7 to 10, and wherein the at least one silver salt is thermally decomposable at >160° C.