Ceramic Lead Terminal Recess for Solder Crack Suppression
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Solution Overview
Problem
Ceramic electronic components with lead terminals often experience cracks due to shrinkage stress from soldering, which compromises their moisture resistance and mechanical strength.
Innovation Solution
A ceramic electronic component design featuring a lead terminal with a recessed area that attracts molten solder, reducing the contact angle and stress at the solder fillet, thereby minimizing crack formation. The recess is strategically positioned to redirect solder flow and reduce distortion during solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead terminals are soldered by dipping in a solder bath, then the lead terminals are connected to the end-face electrode, but shrinkage stress during solder solidification causes cracks inside the ceramic element body
Solution Approach 1:
The lead terminal is designed with a recess at its tip, creating a localized feature that specifically addresses the solder fillet formation area. This local modification causes molten solder to be attracted into the recess, reducing the contact angle and shrinkage stress at the critical interface between the solder fillet and ceramic element body, thereby suppressing crack generation while maintaining overall connection strength
2Reliability
If a solder fillet is formed between the lead terminal and terminal electrode, then electrical connection is achieved, but the solder fillet generates shrinkage stress that creates cracks in the ceramic element body
Solution Approach 1:
The recess at the tip of the lead terminal creates a localized structure that modifies solder fillet formation. By attracting molten solder into the recess, the design changes the local geometry of the solder fillet, reducing its contact angle with the ceramic element body and thereby reducing the shrinkage stress it generates, which suppresses crack formation and improves moisture resistance
Solution Approach 2:
The invention converts the potentially harmful shrinkage stress of the solder fillet into a beneficial effect by using the recess to redirect solder flow. The molten solder is attracted into the recess during solidification, which reduces the contact angle and transforms the stress-generating fillet into a stress-reducing structure, thereby converting the harmful shrinkage stress into a beneficial crack-suppressing mechanism
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 effectively suppresses crack generation within the ceramic element body while enhancing the connecting strength of the lead terminal to the end-face electrode, improving the component's reliability and performance.
Implementation Method 1
the molten solder staying in the area where the solder fillet is formed is attracted to the first recess side during soldering
Implementation Method 2
a fillet is formed between the lead terminal and the terminal electrode by the solder getting wet and spreading
Data Source
AI summary
A ceramic electronic component including: a ceramic element body including an end surface extending along a first axis, and a side surface extending along a second axis and intersecting the end surface; an end-face electrode formed on the end surface of the ceramic element body; and a lead terminal connected to the end-face electrode by soldering. The lead terminal includes: an adjacent part overlapping the end-face electrode in a side view from the second axis; and an extension part extending from an end of the adjacent part in a direction away from a plane including the side surface. A first recess is formed at the extension part and is recessed in a direction away from a plane including the end surface, and the first recess exists at a position close to the end of the adjacent part.