Ceramic Electronic Component Diffusion-Bonded Terminals
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Solution Overview
Problem
Ceramic electronic components face reliability issues due to stress-induced fractures and cracks from mechanical stress and thermal changes, which existing soldering methods fail to address effectively, especially under high temperature and thermal-cycle environments, and the use of lead-based solders is becoming less acceptable due to hazardous substance restrictions.
Innovation Solution
A ceramic electronic component with external electrodes and metal terminals that are directly diffusion-bonded using a process where metal from the terminal is diffused into the electrode, eliminating the need for solder and enhancing bonding reliability and heat resistance, with specific metal compositions and plating films accelerating diffusion and improving bonding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering methods are used to bond metal terminals to external electrodes, then bonding is achieved, but bonding reliability decreases due to insufficient reflow heat resistance and deterioration under high temperature and thermal-cycle environments
Solution Approach 1:
The invention extracts and eliminates the solder material from the bonding interface between metal terminals and external electrodes. By removing the solder layer, the patent avoids the inherent weaknesses of solder joints under thermal stress, achieving direct bonding between the terminal and electrode that maintains reliability at high temperatures and during thermal cycling without solder deterioration or intermetallic compound formation.
Solution Approach 2:
The invention employs composite material structures where the external electrode itself serves as both the electrical conductor and the bonding substrate. The electrode is constructed with specific compositional gradients and microstructures that enable direct diffusion bonding with metal terminals, replacing the traditional solder joint composite structure with a more thermally stable integrated composite that resists thermal degradation.
2Reliability
If lead-based solder is used for bonding, then bonding is achieved, but the use becomes less acceptable due to hazardous substance restrictions
Solution Approach 1:
The invention extracts and eliminates lead-based solder from the bonding process entirely. By removing the hazardous substance (lead solder) from the system, the patent achieves compliance with hazardous substance restrictions while simultaneously improving bonding reliability through direct diffusion bonding that creates stronger, more thermally stable joints without the health and environmental concerns associated with lead.
3Reliability
If metal terminals are directly diffusion-bonded to external electrodes, then bonding reliability and heat resistance are improved, but the process complexity increases
Solution Approach 1:
The invention utilizes parameter changes in the external electrode's composition and microstructure to enable direct diffusion bonding. By controlling the electrode's material parameters (compositional gradients, phase distribution, grain structure) during manufacturing, the patent creates an electrode that naturally facilitates diffusion bonding with metal terminals, achieving high reliability joints through material parameter optimization rather than complex bonding process equipment.
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 direct diffusion-bonding method provides a ceramic electronic component with high reliability and improved heat resistance and thermal shock resistance, reducing the risk of cracks and maintaining bonding strength under various environmental conditions without the need for lead-based solders, thus addressing the limitations of existing soldering techniques.
Implementation Method 1
the external electrode and the metal terminal are directly diffusion-bonded by diffusion of metal in the metal terminal into the external electrode
Implementation Method 2
heating the external electrode and the metal terminal while being contacted to diffuse metal in the metal terminal into the external electrode for direct diffusion-bonding
Data Source
AI summary
A ceramic electronic component has a ceramic element assembly, external electrodes, and metal terminals. The external electrodes are arranged on the surface of the ceramic element assembly. The external electrodes contain a sintered metal. The metal terminals are electrically connected to the external electrodes, respectively. The external electrode and the metal terminal are directly diffusion-bonded by diffusion of metal in the metal terminals into the external electrodes. The above arrangement provides a ceramic electronic component having highly reliable metal particle bonding and a method for manufacturing the same.