Uneven External Electrode Adhesion in Stacked Inductors

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Solution Overview

Problem

Conventional electronic components, such as stacked inductors, face breakage issues during the production process due to stress-induced internal stresses between the laminate and external electrodes, leading to cracks in the insulating layers.

Innovation Solution

The electronic component design includes a laminate with uneven side surfaces on the external electrodes, which increases adhesion with the insulator layers, and a production method that forms conductive layers overlapping openings in the insulator layers to enhance the bonding between the laminate and external electrodes, thereby reducing the likelihood of breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the external electrode has a flat side surface, then the manufacturing process is simple, but the adhesion between the external electrode and insulator layers is insufficient, leading to laminate breakage

Engineering Contradiction:

Improveadhesion between external electrode and insulator layersVSAvoidcomplexity of external electrode structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The side surface of the external electrode is formed with an uneven shape featuring protrusions and recesses, replacing a flat surface. This curved/irregular geometry increases the contact area and mechanical interlocking with the insulator layers, thereby enhancing adhesion strength without adding complex assembly steps

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The uneven shape is applied specifically to the side surface of the external electrode that contacts the insulator layers, while other portions of the electrode maintain their functional geometry. This localized modification targets the adhesion problem area without unnecessarily complicating the entire electrode structure

Inventive Principle:

Principle #3Local quality

2Strength

If the conductive layer area is small, then the material usage is reduced, but the bonding area between the external electrode and insulator layers is insufficient

Engineering Contradiction:

Improvebonding between laminate and external electrodeVSAvoidamount of conductive material

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The conductive layer is designed to extend not only in the planar direction but also to overlap vertically with the openings in the insulator layers. This three-dimensional configuration increases the effective bonding area by utilizing the vertical dimension, providing stronger adhesion without requiring a proportional increase in material quantity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9424980B2Electronic component and method of producing same

Publication Date: 2016.08.23 MURATA MFG CO LTD

AI summary

A laminate in which plural insulator layers are stacked includes an external electrode that is exposed to the exterior of the laminate and includes a plurality of conductive layers stacked in a staking direction and passing through some of the plural insulator layers in the stacking direction. At least one side of the external electrode facing in the stacking direction is overlaid with rest of the plural insulator layers. At least one side surface of the external electrode facing in the stacking direction is uneven with another portion of the side surface.