MLCC External Electrode Structure for Cu Plating Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The adhesion between the base electrode layer and the Cu-plated layer in multilayer ceramic capacitors is poor due to the glass portion of the base electrode layer not adhering well with the Cu-plated layer after firing.
Innovation Solution
The multilayer ceramic capacitor design includes a base electrode layer with a Cu region and a glass region, where the glass region includes a Cu-including glass region, allowing for improved adhesion with the Cu-plated layer through the formation of a Si low density glass region that facilitates better bonding during Cu plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base electrode layer with glass is formed by firing paste including Cu and glass, then the base electrode layer is created, but the glass remains as a glass mass that does not mix with Cu and fails to adhere to the Cu-plated layer
Solution Approach 1:
The invention creates a specific regional structure within the base electrode layer by controlling Cu particle distribution. Cu particles are concentrated at the glass surface region, forming a Cu-rich zone that serves as an intermediate layer. This local compositional variation enables the glass surface to adhere to the Cu-plated layer while maintaining the overall glass matrix structure.
Solution Approach 2:
The invention changes the physical and chemical parameters of the glass surface region by controlling Cu particle distribution and concentration. By adjusting the Cu particle size, distribution density, and concentration at the glass surface, the adhesion properties are optimized. The Cu-including glass region has different compositional parameters than the bulk glass, enabling improved bonding.
2Reliability
If Cu-plated layer is formed on base electrode layer, then external electrode structure is completed, but adhesion between the two layers remains poor due to glass mass not bonding with Cu
Solution Approach 1:
The Cu-rich region at the glass surface acts as an intermediary layer between the glass matrix and the Cu-plated layer. This intermediate zone with optimized Cu concentration and particle distribution facilitates bonding by providing a transition region that is chemically and physically compatible with both the glass substrate and the plated Cu layer, eliminating poor adhesion issues.
Solution Approach 2:
The base electrode layer is designed as a composite structure with multiple phases: glass matrix, Cu particles dispersed in the glass, and a Cu-rich surface region. This composite architecture combines the properties of glass (sealing, insulation) with Cu (conductivity, adhesion), creating a multi-functional base electrode layer that resolves the adhesion problem.
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 enhances the adhesion between the base electrode layer and the Cu-plated layer, improving sealing properties and reducing hydrogen diffusion, thereby maintaining insulation resistance and facilitating easier mounting.
Implementation Method 1
the glass region of the base electrode layer includes a Cu-including glass region including Cu... improved adhesion between a base electrode layer and a Cu-plated layer
Implementation Method 2
formation of a Si low density glass region that facilitates better bonding during Cu plating
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including internal electrode layers and internal dielectric layers alternatively laminated therein, main surfaces on both sides in a lamination direction, end surfaces on both sides in a length direction intersecting the lamination direction, and lateral surfaces on both sides in a width direction intersecting the lamination direction and the length direction, and two external electrodes on the end surfaces of the multilayer body, wherein the two external electrodes each include a base electrode layer including a Cu region and a glass region respectively including Cu and Si as a main component, and a Cu-plated layer outside the base electrode layer, and the glass region of the base electrode layer includes a Cu-including glass region including Cu.