MLCC External Electrode Structure for Crack-Resistant Mounting
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Solution Overview
Problem
Multilayer ceramic capacitors experience non-uniform stress distribution and reduced adhesion strength due to thermal expansion and contraction, leading to cracks when mounted on substrates, especially when using external electrodes with glass-containing first electrode layers fired at high temperatures.
Innovation Solution
A multilayer electronic component design featuring external electrodes with a first electrode layer made of copper or its alloys, free of glass, and a second electrode layer including silver, palladium, and platinum, with controlled thickness between 1 μm and 10 μm, to reduce stress concentration and improve adhesion without glass inclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a first electrode layer containing glass is formed by firing at high temperature (700-800°C), then the external electrode achieves good adhesion to the body, but non-uniform stress distribution occurs due to thermal expansion and contraction, causing cracks and reduced adhesion strength
Solution Approach 1:
The patent removes glass from the first electrode layer composition. By extracting the glass component that causes non-uniform stress distribution during high-temperature firing, the invention eliminates the source of thermal stress-induced cracks while maintaining adhesion strength through alternative materials and processes.
Solution Approach 2:
The patent changes the formation parameters of the first electrode layer by using copper particles and forming it at a low temperature (room temperature or near-room temperature) instead of high-temperature firing (700-800°C). This parameter change eliminates thermal expansion and contraction stresses while achieving adequate adhesion.
2Reliability
If the first electrode layer is formed by high-temperature firing (700-800°C), then the electrode achieves good conductivity, but thermal expansion and contraction cause non-uniform stress distribution and cracks
Solution Approach 1:
The patent changes the formation temperature parameter from high temperature (700-800°C) to low temperature (room temperature or near-room temperature). This parameter change eliminates thermal stress while maintaining electrode conductivity through the use of copper particles and alternative formation methods that do not require high-temperature firing.
3Strength
If glass is included in the first electrode layer, then the electrode structure achieves good adhesion, but stress concentration occurs during thermal cycles, leading to reduced adhesion strength after mounting
Solution Approach 1:
The patent extracts glass from the first electrode layer composition. By removing the glass component that causes stress concentration during thermal cycles, the invention eliminates the source of adhesion degradation while maintaining good adhesion strength through copper particles and alternative bonding mechanisms.
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
This design enhances the reliability and capacitance characteristics of the multilayer electronic component by minimizing stress-induced cracks and maintaining strong adhesion even after mounting on substrates, while allowing for low-temperature formation of the first electrode layer using copper particles.
Implementation Method 1
allowing for low-temperature formation of the first electrode layer using copper particles
Data Source
AI summary
A multilayer electronic component includes a body including a dielectric layer and first and second internal electrodes alternately disposed with the dielectric layer interposed therebetween, a first external electrode disposed on the body and connected to the first internal electrode, and a second external electrode disposed on the body and connected to the second internal electrode, wherein the first and second external electrodes include a first electrode layer disposed on the body and including one or more of copper (Cu), nickel (Ni), and alloys thereof and a second electrode layer disposed on the first electrode layer, including silver (Ag) and further including one or more of palladium (Pd), platinum (Pt), and gold (Au), wherein the first electrode layer does not include glass and an average thickness of the first electrode layer is 1 μm or more and 10 μm or less.