Conductive Paste with Copper-Tin-Manganese Powder
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Solution Overview
Problem
Conductive pastes used for forming conductor patterns on substrates face challenges with electromigration resistance, soldering heat resistance, and adhesion to the substrate, with existing solutions either compromising conductivity or requiring complex production steps.
Innovation Solution
A sintering type conductive paste is developed, comprising silver powder, glass frit, an organic binder, and a powder containing copper, tin, and manganese, which improves electromigration resistance, soldering heat resistance, and adhesion to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver powder is used as conductive material, then electromigration resistance is improved, but soldering heat resistance deteriorates due to sintering of silver particles
Solution Approach 1:
Copper powder acts as an intermediary material between silver particles. The copper powder prevents direct contact and sintering of silver particles during soldering heat exposure, while still allowing electrical conductivity. This mediator approach resolves the contradiction by protecting silver from sintering without compromising the electromigration resistance that silver provides.
Solution Approach 2:
The conductive paste uses a composite formulation combining silver powder, copper powder, glass frit, and organic binder. This composite structure allows silver to provide electromigration resistance while copper and glass frit work together to prevent silver sintering during soldering, achieving both electromigration resistance and soldering heat resistance simultaneously.
2Quantity of substance
If copper powder is used as conductive material, then cost is reduced and conductivity is improved, but adhesion to substrate deteriorates
Solution Approach 1:
Glass frit acts as an intermediary bonding material between copper particles and the substrate. The glass frit contains components that react with both copper and the substrate (such as alumina), forming strong chemical bonds. This mediator enables copper to provide cost-effectiveness and conductivity while glass frit ensures proper adhesion to the substrate.
Solution Approach 2:
The composite paste formulation combines copper powder with glass frit and organic binder. The glass frit component specifically addresses the adhesion problem by providing chemical bonding to the substrate, while copper provides the desired electrical conductivity and cost benefits. This composite approach resolves the adhesion issue without sacrificing the advantages of copper.
3Reliability
If copper powder is used as conductive material, then conductivity is improved, but oxidation resistance deteriorates requiring protective coating
Solution Approach 1:
Glass frit serves as a protective intermediary layer around copper particles. During firing, the glass frit forms a glassy matrix that encapsulates the copper particles, preventing direct exposure to oxygen and thus preventing oxidation. This mediator approach allows copper to maintain high conductivity while being protected from oxidation by the glass frit barrier.
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 conductive paste achieves excellent electromigration resistance, soldering heat resistance, and substrate adhesion, while maintaining high conductivity and simplifying production processes.
Implementation Method 1
Conductive paste of the firing type is conductive paste having conductivity secured by sintering metal particles with each other due to firing
Implementation Method 2
conductive paste including (A) silver powder, (B) glass frit, (C) organic binder, and (D) powder containing copper, tin, and manganese
Implementation Method 3
conductive paste having metal particles dispersed in a vehicle of an organic binder and a solvent
Data Source
Figure 1(a)~1(d)
AI summary
Provided is sintering type conductive paste excellent in electromigration resistance, soldering heat resistance, and adhesion to a substrate. The conductive paste of the present invention contains silver powder (A), glass frit (B), an organic binder (C), and powder (D) containing copper, tin, and manganese. It is preferred that the conductive paste of the present invention contains from 0.1 to 5.0 parts by mass of the powder (D) based on 100 parts by mass of the silver powder (A).