Copper-Silver Interface Bonding Using a Cu2O Interlayer

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Solution Overview

Problem

There is a need for a method to form reliable interfaces between copper and silver layers in semiconductor module arrangements that maintain both electrical conductivity and mechanical strength over the lifetime of the module.

Innovation Solution

A method that involves bringing a silver layer into direct contact with a copper layer in an oxygen-containing atmosphere and heating them to form a copper(I) oxide layer, Cu2O, between the two layers, which alleviates lattice mismatch and enhances mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper and silver layers are brought into direct contact to form an interface, then electrical conductivity is maintained, but mechanical strength at the interface is insufficient

Engineering Contradiction:
Improveinterface reliabilityVSAvoidinterface mechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A copper(I) oxide layer is introduced as an intermediary between the copper and silver layers. This intermediate layer has a crystal structure that serves as a bridge, improving mechanical bonding between the two metal layers while maintaining electrical conductivity through the interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The crystal structure and composition of the interface are changed by forming copper(I) oxide with specific lattice parameters. The lattice constant of copper(I) oxide (0.427 nm) is positioned between that of copper (0.361 nm) and silver (0.409 nm), creating a gradual transition that reduces lattice mismatch and enhances mechanical strength.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a copper(I) oxide layer is formed between copper and silver layers, then mechanical strength increases, but electrical conductivity may be affected

Engineering Contradiction:
Improveinterface mechanical strengthVSAvoidelectrical conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The thickness and composition of the copper(I) oxide layer are precisely controlled to maintain electrical conductivity. By optimizing the lattice parameters and keeping the oxide layer thin, electrical current can still pass through effectively while gaining mechanical strength benefits.

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 formation of a copper(I) oxide layer between copper and silver layers significantly increases the mechanical strength of the interface while maintaining electrical conductivity, addressing the reliability of copper-silver interfaces in semiconductor modules.

Implementation Method 1

heating the second layer or element being in direct contact with the first layer or element in an oxygen containing atmosphere, thereby forming a third layer consisting of copper(I) oxide, Cu2O

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4648094A1Method for connecting two metal layers and arrangement comprising two metal layers connected to each other
Publication Date: 2025.11.12 INFINEON TECHNOLOGIES AG
  • EP4648094A1 patent drawingFigure 1~3
  • EP4648094A1 patent drawingFigure 4A~5
  • EP4648094A1 patent drawing

AI summary

A method comprises bringing a first layer or element (92) comprising or consisting of silver in direct contact with a second layer or element (90) consisting of copper or a copper alloy, and heating the second layer or element (90) being in direct contact with the first layer or element (92) in an oxygen containing atmosphere, thereby forming a third layer (94) consisting of copper(I) oxide, Cu2O, between the first layer or element (92) and the second layer or element (90), wherein the third layer (94) directly adjoins the first layer or element (92) and the second layer or element (90).