Chip Electronic Component Resin Electrode Adhesion Control
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Solution Overview
Problem
Chip-type electronic components, such as laminated ceramic capacitors, face reliability issues due to cracking and moisture infiltration when subjected to substrate deflection stress, leading to defective short-circuits and decreased reliability.
Innovation Solution
A chip-type electronic component with a ceramic body and external electrodes comprising a resin electrode layer with a conductive and resin constituent, and a plating metal layer, where the adhesion strength between the ceramic body and the resin electrode layer is higher than between the resin electrode layer and the plating metal layer, ensuring that stress is absorbed by the interface between the resin electrode layer and the plating metal layer, preventing ceramic body cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external electrode is formed with a first electrode layer by sintering conductive paste and a second electrode layer with conductive resin, then electrical conduction is achieved, but deflection stress concentrates on the ends of these layers causing ceramic body cracking
Solution Approach 1:
A resin electrode layer is introduced as an intermediary between the thick-film electrode layer and the plating metal layer. This resin layer has lower adhesion strength to the plating metal than to the ceramic body, creating a stress-absorbing interface that prevents stress concentration at the ends of the electrode structure, thereby preventing ceramic body cracking while maintaining electrical conduction.
Solution Approach 2:
The adhesion strength parameters of the resin electrode layer are specifically controlled to be lower than both the thick-film electrode layer-ceramic body interface and the plating metal layer-resin electrode layer interface. This parameter optimization allows the resin layer to absorb deflection stress through controlled deformation, protecting the ceramic body from stress concentration.
2Strength
If the first conductor layer contains glass constituent and the second conductor layer contains resin constituent, then connection strength requirements can be met, but fracturing occurs between layers during substrate bending test allowing moisture infiltration
Solution Approach 1:
The external electrode is constructed as a composite structure with a resin electrode layer containing conductive particles dispersed in a resin matrix. This composite structure provides both electrical conduction and flexible stress absorption, preventing the fracturing that occurs in glass-resin layered structures while maintaining connection strength and blocking moisture infiltration paths.
3Reliability
If the adhesion strength between resin electrode layer and plating metal layer is high, then electrical connection is stable, but stress cannot be absorbed causing ceramic body cracking
Solution Approach 1:
The adhesion strength of the resin electrode layer is differentiated at different interfaces: it has high adhesion strength to the thick-film electrode layer (ensuring electrical connection stability) and low adhesion strength to the plating metal layer (enabling stress absorption). This local quality differentiation allows the resin layer to simultaneously provide stable electrical connection and absorb deflection stress without causing ceramic body cracking.
Data Source
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AI summary
An object of the present invention is to provide a chip-type electronic component with high reliability, which is able to suppress and prevent fatal damage to a ceramic body (10) due to cracking even if a substrate with the chip-type electronic component mounted thereon undergoes a deflection. The chip-type electronic component is configured to include: a ceramic body (10) including internal electrodes (3a,3b); resin electrode layers (12a,12b) formed in a region including at least end surfaces of the ceramic body (10), and formed to connect to the internal electrodes (3a,3b) directly or indirectly and connect with the ceramic body (10); and plating metal layers (13a,13b) formed to cover the resin electrode layers (12a,12b), wherein the adhesion strength between the ceramic body (10) and the resin electrode layer (12a,12b) is higher than the adhesion strength between the resin electrode layer (12a,12b) and the plating metal layer (13a,13b).