Cu-Sn-Ti Bonding Layer for Silver-Free Metal-Ceramic Substrates

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Solution Overview

Problem

Existing metal-ceramic composite substrates using active metal brazing with silver (Ag) face increased manufacturing costs and deteriorated physical properties due to silver migration under high heat, necessitating a solution that maintains bonding strength and thermal stability without silver.

Innovation Solution

A metal paste composition comprising copper (Cu), tin (Sn), and titanium (Ti) within specific weight percentages, excluding silver, forms a bonding layer between a ceramic substrate and a metal layer, enhancing bonding strength and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If silver (Ag) is used in active metal brazing, then bonding strength is improved, but manufacturing cost increases and physical properties deteriorate due to silver migration under high heat

Engineering Contradiction:

Improvebonding strengthVSAvoidphysical properties stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent removes silver (Ag) from the metal paste composition entirely, extracting the problematic element that causes migration and property deterioration while maintaining bonding strength through alternative metal combinations of copper, tin, and titanium

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite metal paste composition consisting of copper (67-83 wt%), tin (15-32 wt%), and titanium (0.5-1.7 wt%), where the synergistic combination of these metals achieves both strong bonding and thermal stability without silver migration issues

Inventive Principle:

Principle #40Composite materials

2Strength

If silver (Ag) is used in active metal brazing, then bonding strength is improved, but manufacturing cost increases

Engineering Contradiction:

Improvebonding strengthVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces expensive silver with more cost-effective metals (copper, tin, titanium) that provide equivalent or superior bonding performance, significantly reducing material costs while maintaining bonding strength

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the compositional parameters of the metal paste by eliminating silver and adjusting the ratios of copper, tin, and titanium to achieve optimal bonding strength at lower cost

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 solution ensures uniform bonding across the entire area, improving reliability and insulation resistance, while preventing cracks and peeling in thermal cycles, suitable for high-temperature and high-voltage environments.

Implementation Method 1

AMB is a method of forming a layer by brazing an active metal onto a ceramic substrate

Methodology Applied

Scientific EffectBrazing: Brazing

Implementation Method 2

there is a problem that the manufacturing cost is increased and the physical properties are deteriorated due to the migration of silver (Ag) when high heat is generated

Methodology Applied

Scientific EffectThermal stability:

Data Source

PatentEP4640363A1Metal paste composition and metal-ceramic composite substrate comprising the same

Publication Date: 2025.10.29 KCC CORP

Figure 1

AI summary

The present disclosure relates to a metal paste composition and a metal-ceramic composite substrate comprising the same. The metal paste composition comprises 67 to 83 wt% of copper (Cu), 15 to 32 wt% of tin (Sn), and 0.5 to 1.7 wt% of titanium (Ti) and a ceramic substrate. The metal-ceramic composite substrate comprises a ceramic substrate; a bonding layer formed on the ceramic substrate and composed of the metal paste composition of the present disclosure; and a metal layer formed on the bonding layer.