Multilayer Capacitor Electrode Structure Against Plating Erosion
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Solution Overview
Problem
Multilayer ceramic capacitors face reliability issues due to erosion of external electrodes from plating solutions, which compromises durability and moisture resistance.
Innovation Solution
The electronic component features external electrodes with a structure comprising a first electrode layer connected to internal electrodes and a second electrode layer, where the area proportion of glass in the first electrode layer is greater than in the second, and the second electrode layer has a thickness of 6 μm or more, minimizing erosion and maintaining adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plating is performed on the external electrode surface, then the electronic component can be mounted on printed circuit boards, but the plating solution erodes the external electrode components, reducing reliability
Solution Approach 1:
The external electrode is divided into multiple layers (first electrode layer and second electrode layer) with different compositions. The first electrode layer contains glass components for adhesion to the ceramic body, while the second electrode layer has reduced glass content to resist plating solution erosion. This segmentation allows each layer to perform its specific function optimally.
Solution Approach 2:
Different regions of the external electrode are given different material properties. The first electrode layer near the ceramic body has high glass content for strong adhesion, while the second electrode layer on the outer surface has low glass content for plating solution resistance. This local quality differentiation resolves the contradiction between adhesion and erosion resistance.
2Strength
If the external electrode contains glass components for adhesion, then it maintains strong bonding to the ceramic body, but the glass components are eroded by the plating solution
Solution Approach 1:
The external electrode is segmented into two layers with different glass contents. The first electrode layer contains glass components (area proportion ≥ 5%) that provide strong adhesion to the ceramic body through chemical bonding. The second electrode layer has reduced glass content (area proportion < 5%) that protects the underlying glass-containing layer from plating solution erosion.
Solution Approach 2:
The first electrode layer acts as an intermediary between the ceramic body and the second electrode layer. It provides the necessary adhesion to the ceramic body while being protected by the second electrode layer from direct contact with the plating solution, thus preventing erosion of the glass components.
Data Source
AI summary
An electronic component includes: a body including a stack structure formed of a plurality of dielectric layers and internal electrodes alternately stacked with the dielectric layers interposed therebetween; and an external electrode disposed outside the body, connected to the internal electrode, and including conductive metal and glass, in which the external electrode includes a first electrode layer connected to the internal electrode and a second electrode layer disposed on the first electrode layer, an area proportion of the glass of the first electrode layer is greater than that of the glass of the second electrode layer, and a thickness of the second electrode layer is 6 μm or more.