Copper Electrode Bonding on Ceramic Substrates Without High-Heat Peeling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Copper electrodes on ceramic substrates tend to peel off due to poor adhesion, especially under thermal stress, despite efforts to enhance interfacial adhesion strength through high-temperature sintering with oxide additives, which can lead to ceramic substrate breakage.
Innovation Solution
A method involving the application of a paste containing copper, copper oxide, and inorganic oxide particles with a softening point, followed by sintering and a softening step in an inert gas atmosphere, to form a strong adhesion between copper electrodes and inorganic substrates, with specific temperature and composition controls to optimize adhesion and prevent substrate breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature sintering (800-1000°C) is performed to improve adhesion between copper electrode and ceramic substrate, then interfacial adhesion strength is improved, but thermal stress during cooling increases and ceramic substrate may break
Solution Approach 1:
The invention changes the sintering temperature parameter from conventional high temperature (800-1000°C) to a lower range (600-800°C), and introduces a two-stage heating process with a softening step (800-900°C for 0.5-2 hours) after sintering. This parameter optimization reduces thermal stress while achieving adequate adhesion strength, preventing substrate breakage during cooling.
Solution Approach 2:
The invention uses glass frit (inorganic oxide particles with softening point 700-900°C) as an intermediary material between the copper electrode and ceramic substrate. The glass frit softens during the softening step and forms a bonding phase that enhances adhesion without requiring high-temperature sintering, thereby reducing thermal stress on the substrate.
2Ease of manufacture
If copper paste is used to reduce manufacturing cost, then manufacturing cost is reduced, but adhesion between copper electrode and ceramic substrate deteriorates
Solution Approach 1:
The invention creates a composite electrode structure by combining copper particles (for conductivity and cost-effectiveness) with glass frit particles (for adhesion). The glass frit acts as a bonding agent that enhances the adhesion between copper and ceramic substrate, allowing the use of inexpensive copper paste while achieving strong adhesion through the composite material system.
3Reliability
If sintering temperature is reduced to prevent substrate breakage, then substrate integrity is maintained, but adhesion between copper electrode and ceramic substrate deteriorates
Solution Approach 1:
The invention segments the heating process into two distinct stages: (1) sintering at 600-800°C to form the copper electrode structure, and (2) softening at 800-900°C to activate the glass frit bonding phase. This segmentation allows each stage to optimize for its specific function, achieving both substrate integrity and adhesion strength.
Solution Approach 2:
The invention utilizes the phase transition (softening) of glass frit at 700-900°C as the key mechanism for adhesion enhancement. During the softening step, the glass frit transitions from a rigid particulate state to a softened state that can flow and bond with both copper and ceramic surfaces, creating strong adhesion without requiring high-temperature sintering that would stress the substrate.
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 achieves strong adhesion between copper electrodes and inorganic substrates, enhancing the mechanical reliability and reducing electrical resistance of the electronic components while preventing substrate breakage during thermal cycles.
Implementation Method 1
a sintering step of forming a sintered body including at least copper through heating in an inert gas atmosphere at a temperature equal to or higher than a sintering temperature of the copper particles
Implementation Method 2
a softening step of performing heating in an inert gas atmosphere at a temperature equal to or higher than the softening point of the inorganic oxide particles
Data Source
AI summary
The purpose of the present invention is to provide an electronic component in which a copper electrode and an inorganic substrate exhibit strong adhesion to each other. A method for producing an electronic component according to the present invention comprises: an application step wherein a paste is applied onto an inorganic substrate, which paste contains copper particles, copper oxide particles and/or nickel oxide particles, and inorganic oxide particles having a softening point; a sintering step wherein a sintered body which contains at least copper is formed by means of heating in an inert gas atmosphere at a temperature that is less than the softening point of the inorganic oxide particles but not less than the sintering temperature of the copper particles; and a softening step wherein heating is carried out in an inert gas atmosphere at a temperature that is not less than the softening point of the inorganic oxide particles.