Copper-Silicon External Electrode Structure Against Plating Penetration
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Solution Overview
Problem
The penetration of plating solution into the underlying electrode causes peeling off of the underlying electrode and metal layer in existing electronic components, leading to undesirable separation.
Innovation Solution
The underlying electrode is composed of copper and silicon, with copper particles having a flattening ratio of 0.5 or less, and silicon distributed to fill gaps between copper particles, forming a dense film to prevent plating solution penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional underlying electrode is used, then the plating process can be performed, but the plating solution penetrates into the underlying electrode causing peeling off
Solution Approach 1:
The underlying electrode is formed as a composite material containing copper particles and silicon particles. The silicon particles fill the gaps between copper particles to create a dense structure that prevents plating solution penetration, while maintaining electrical conductivity through the copper network.
Solution Approach 2:
The patent controls the particle size ratio of silicon to copper particles (0.3 to 0.8), the density of silicon particles (2.2 to 3.5 g/cm³), and the content ratio of silicon to copper (5 to 50 mass%). These parameter optimizations create a dense yet conductive structure that blocks plating solution while maintaining electrical function.
2Reliability
If the underlying electrode is made dense to prevent plating solution penetration, then adhesion is improved, but electrical conductivity may be reduced
Solution Approach 1:
The underlying electrode exhibits local quality differentiation where silicon particles are distributed to fill gaps between copper particles, creating regions of high density for barrier function while maintaining copper-dominated pathways for electrical conduction. This local optimization achieves both penetration resistance and conductivity.
Solution Approach 2:
The composite structure combines copper particles (providing electrical conductivity) with silicon particles (providing barrier function). The synergistic combination allows the material to simultaneously achieve low electrical resistance and high resistance to plating solution penetration.
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
The dense film structure effectively prevents the plating solution from penetrating into the underlying electrode, ensuring the integrity of the metal layer.
Implementation Method 1
a difference between a curing onset temperature of the silicon component and a sintering onset temperature of the copper component
Implementation Method 2
a curing onset temperature of the silicon component is higher than a sintering onset temperature of the copper component
Data Source
AI summary
An electronic component that includes: a base body; and an external electrode that covers a part of an outer surface of the base body, the external electrode including: an underlying electrode containing copper and silicon; and a metal layer that covers an outer surface of the underlying electrode, wherein at least some of the copper has copper particles with a flattening ratio of 0.5 or less, and when the underlying electrode is viewed in section, the silicon is distributed so as to fill gaps between the copper particles.