Electronic Component Plating Thickness Variation for Stress Reduction
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Solution Overview
Problem
Electronic components with plating layers experience residual stress issues during soldering, leading to potential cracking and reduced bonding strength, as well as increased risk of moisture infiltration and electrical resistance.
Innovation Solution
The electronic component design features a plating layer with varying thicknesses on different surfaces, where the thickness is smaller on the principal surface and larger on the side surfaces, along with a conductive resin layer to mitigate residual stress and enhance bonding strength, moisture resistance, and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plating layer is applied to the external electrode to ensure bonding strength by soldering, then bonding strength is improved, but residual stress remains in the plating layer which may cause cracks in the element body
Solution Approach 1:
The plating layer is designed with different thicknesses in different regions: a first thickness on the principal surface and a second thickness on the side surfaces. This local quality variation reduces residual stress concentration while maintaining adequate bonding strength where needed.
Solution Approach 2:
The thickness parameter of the plating layer is changed across different surfaces. By making the plating layer thinner on the principal surface compared to the side surfaces, the residual stress is reduced to prevent cracking while still ensuring sufficient bonding strength for soldering.
2Strength
If the plating layer thickness is increased to ensure bonding strength, then bonding strength is improved, but residual stress increases which may cause cracks
Solution Approach 1:
Different regions of the external electrode receive different plating layer thicknesses. The side surfaces have a thicker plating layer for bonding strength, while the principal surface has a thinner plating layer to minimize residual stress.
Solution Approach 2:
The plating layer thickness is made asymmetric across different surfaces of the external electrode. The thickness varies from the principal surface to the side surfaces, creating an asymmetric structure that balances bonding requirements with stress reduction.
3Area of stationary object
If the plating layer covers the entire external electrode surface uniformly, then bonding coverage is improved, but residual stress distribution becomes uneven leading to crack risk
Solution Approach 1:
The plating layer coverage is optimized locally: it covers the side surfaces with greater thickness for bonding area, while covering the principal surface with reduced thickness to maintain stress distribution stability.
Solution Approach 2:
The thickness parameter of the plating layer is changed based on location. By reducing the thickness on the principal surface while maintaining adequate coverage on side surfaces, the stress distribution remains stable while bonding coverage is preserved.
Data Source
AI summary
An element body of a rectangular parallelepiped shape includes a first principal surface arranged to constitute a mounting surface, a second principal surface opposing the first principal surface in a first direction, a pair of side surfaces opposing each other in a second direction, and a pair of end surfaces opposing each other in a third direction. An external electrode is disposed at an end portion of the element body in the third direction. The external electrode includes a conductive resin layer. The external electrode includes a plating layer including a first portion covering the first principal surface and a pair of second portions covering the pair of side surfaces. A thickness of the first portion is smaller than each thickness of the pair of second portions.