Copper Active Brazing Material Without Silver Migration
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Solution Overview
Problem
Existing soldering materials for active soldering of electronic components to ceramic substrates often contain high silver content, leading to high material costs and the risk of silver migration under electric fields.
Innovation Solution
A soldering material composed primarily of copper, with minimal silver content (less than 0.5% by weight), using copper or copper alloys as the main component, and incorporating active metals like titanium to form a bond with ceramics through a reaction layer, thereby reducing production costs and preventing silver migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high silver content is used in soldering material, then bonding reliability is improved, but material cost increases and silver migration risk occurs
Solution Approach 1:
The patent removes silver from the soldering material composition entirely, extracting the harmful element while maintaining bonding functionality through alternative copper-based formulations with reactive metals
Solution Approach 2:
The patent replaces expensive silver with cheaper copper-based materials, using cost-effective copper alloys combined with reactive metals like titanium, aluminum, or silicon to achieve reliable bonding without relying on precious metals
2Reliability
If high silver content is used in soldering material, then bonding reliability is improved, but material cost increases
Solution Approach 1:
The patent replaces expensive silver with cheaper copper-based materials, using cost-effective copper alloys combined with reactive metals like titanium, aluminum, or silicon to achieve reliable bonding without relying on precious metals
Solution Approach 2:
The patent changes the compositional parameters of the soldering material, transitioning from silver-rich formulations to copper-based formulations with controlled additions of reactive metals (1-30 wt.%) and other elements to optimize both cost and performance
3Ease of manufacture
If copper-based soldering material is used instead of silver, then cost is reduced and silver migration is prevented, but bonding capability at low temperatures may be affected
Solution Approach 1:
The patent adjusts compositional parameters by adding reactive metals (1-30 wt.%) and other elements (5-40 wt.%) to the copper-based formulation, enabling control over melting temperature and bonding characteristics to achieve effective soldering in the 650-1000°C range
Solution Approach 2:
The patent creates composite soldering materials combining copper with reactive metals (titanium, aluminum, silicon) and other elements, where the composite structure provides both cost-effectiveness and appropriate thermal bonding properties for ceramic substrates
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 copper-based soldering material effectively connects ceramic layers and metallizations at temperatures between 650-1000°C, reducing production costs and preventing silver migration while maintaining reliable and permanent soldering without the need for silver, and allowing for adjustable melting temperatures and compatibility with various ceramic surfaces.
Implementation Method 1
the active metal, which is titanium, forms a bond between the soldering material and the ceramic by means of a reaction layer through a chemical reaction
Implementation Method 2
a connection is created between a metal foil, for example, a copper foil, and a ceramic substrate, for example, an aluminum nitride ceramic, using a soldering material at a temperature between approximately 650 and 1000 °C
Data Source
Figure 1
AI summary
The invention relates to a soldering material (1) for active soldering, in particular for active soldering a support layer (2) comprising a metallization (3) on a ceramic, the soldering material comprises copper and essentially does not contain any silver.