Ceramic Electronic Component Cu Plating Stress Distribution
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Solution Overview
Problem
Ceramic electronic components face strength reduction and cracking issues due to stress concentration at the tip portions of external electrodes during mounting, especially with the miniaturization of electronic devices.
Innovation Solution
The external electrode structure of ceramic electronic components is designed with a Cu plating layer that extends over a gap region between electrodes, satisfying the expression 0.1≦t/d≦0.5, where t is the thickness of the Cu plating layer and d is the distance from the base layer end to the Cu plating layer end, dispersing stress and preventing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size and thickness of ceramic electronic components are reduced, then the component size and thickness decrease, but the strength of the ceramic electronic components decreases
Solution Approach 1:
The patent applies local quality by creating a tapered plating layer structure where the thickness varies locally - thicker at the base layer end and thinner at the tip portion. This localized variation in plating thickness optimizes stress distribution at critical regions without increasing overall component size, thereby maintaining strength while allowing size reduction.
Solution Approach 2:
The patent changes the geometric parameter of the plating layer by controlling the thickness ratio (t/d) to be between 0.05 and 0.5. This parameter optimization allows the plating layer to effectively disperse stress while minimizing material usage and component size, resolving the contradiction between size reduction and strength maintenance.
2Volume of moving object
If the height of the monolithic ceramic capacitor is reduced, then the thickness decreases, but stress concentration at the tip portion of external electrodes increases
Solution Approach 1:
The patent addresses stress concentration by implementing local quality variation in the plating layer thickness. The plating layer is designed to be thicker near the base layer and gradually thinner toward the tip, creating a stress-distributing gradient that prevents stress concentration at the tip portion even when overall capacitor thickness is reduced.
Solution Approach 2:
The patent employs a tapered geometry for the plating layer, creating a curved transition rather than an abrupt edge. This curved configuration helps distribute stress more evenly along the external electrode structure, preventing stress concentration points that would occur with sharp edges or uniform thickness.
3Strength
If the Cu plating layer thickness is increased, then stress resistance improves, but the t/d ratio exceeds the optimal range
Solution Approach 1:
The patent optimizes the t/d ratio parameter to fall within the range of 0.05 to 0.5, which balances stress resistance with manufacturing feasibility. This parameter control ensures adequate stress resistance while maintaining practical manufacturing precision, avoiding the need for excessively thick plating layers that would be difficult to manufacture consistently.
Data Source
AI summary
A ceramic electronic component includes a ceramic body, a first external electrode, and a second external electrode. The first and second external electrodes are disposed on a principal surface, which is directed to the mounting surface side, of the ceramic body so as to face each other with a predetermined gap region therebetween. The external electrodes each include a base layer and a Cu plating layer which covers the base layer. In each of the first and second external electrodes, an expression 0.1≦t/d≦0.5 is satisfied, where t is a thickness of the Cu plating layer at an end of the base layer on a gap region side, and d is a distance from the end of the base layer on the gap region side to an end of the Cu plating layer on the gap region side.