Ceramic Multilayer Substrate Recessed Electrode Plating Corrosion

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Solution Overview

Problem

The peeling strength of surface electrodes on ceramic multilayer substrates is compromised due to the presence of plating liquids, which can lead to corrosion and reduced reliability, especially at the peripheral end portions where the plating liquid tends to remain and cause interface fragility.

Innovation Solution

A ceramic multilayer substrate design featuring a recess portion inward from the peripheral end of the surface electrode, which prevents corrosion by containing the plating liquid and maintaining a higher thickness in the affected area, thereby enhancing the peeling strength and reliability of the surface electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plating step is performed to form a plating film on the surface electrode, then the electrical conductivity and corrosion resistance are improved, but the plating liquid remains on the surface causing interface fragility and reduced peeling strength

Engineering Contradiction:

Improvepeeling strength of surface electrodeVSAvoidcorrosion by remaining plating liquid

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The surface electrode is divided into a peripheral end portion and an inner portion, with the peripheral end portion having a reduced thickness or recessed structure. This segmentation allows the plating liquid to be contained in the recessed region rather than reaching the critical peripheral end portion, thereby preventing corrosion at the most vulnerable area while still allowing plating on the inner portion for maintaining electrical conductivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cover ceramic layer is introduced as an intermediary structure between the plating liquid and the surface electrode. This cover layer prevents the plating liquid from directly contacting and corroding the peripheral end portion of the surface electrode, while still allowing the plating process to proceed on the electrode surface where needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the peripheral end portion of the surface electrode is covered with a cover ceramic layer to prevent plating liquid contact, then corrosion is prevented, but the plating liquid may enter through the boundary portion between ceramic layer and electrode

Engineering Contradiction:

Improveprotection from plating liquidVSAvoidboundary structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of uniformly covering the entire surface electrode with a cover ceramic layer, the invention applies the cover layer selectively or creates a recessed structure only at the peripheral end portion where corrosion risk is highest. This local quality approach provides protection where needed while simplifying the overall structure and reducing the complexity of boundary portions.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If the surface electrode thickness is reduced at the peripheral end portion to prevent plating liquid accumulation, then peeling strength is improved, but the electrode may become more susceptible to mechanical damage

Engineering Contradiction:

Improvepeeling strength controlVSAvoidmechanical strength of electrode

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The electrode structure transitions from a uniform thickness to a dynamic, variable thickness profile where the peripheral end portion has reduced thickness and the inner portion maintains full thickness. This dynamic structure optimizes peeling strength at the critical peripheral regions while preserving mechanical strength in the inner regions that bear the mechanical load.

Inventive Principle:

Principle #15Dynamics

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 recessed design effectively prevents corrosion and maintains a high peeling strength of the surface electrode, ensuring reliable adhesion even after the plating process, reducing the risk of electrode fracture and peeling.

Implementation Method 1

the plating liquid remains in the recess portion (groove) provided in the region located inward from the peripheral end portion of the surface electrode

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a plating liquid used in a plating step of forming a plating film on a surface of the surface electrode

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9681534B2Ceramic multilayer substrate

Publication Date: 2017.06.13 MURATA MFG CO LTD

AI summary

In a ceramic multilayer substrate including a ceramic laminate including ceramic layers, a surface electrode located on a surface of the ceramic laminate, and a cover ceramic layer that covers a peripheral portion of the surface electrode, a recess portion is provided in a peripheral portion of a surface electrode to extend along the periphery thereof, and the peripheral portion of the surface electrode includes a peripheral end portion thereof and a region in which the recess portion is covered with a cover ceramic layer. A height of a central portion of the surface electrode which is not covered with the cover ceramic layer is lower than a height of a primary surface of the ceramic laminate on which the surface electrode is located.