Multilayer Ceramic Electrode Sn Gradient for Humidity and ESR

Solution Overview

Problem

Thin internal electrode layers in ceramic electronic devices are prone to breaking during the firing process, leading to insulation failures due to moisture intrusion, and adding Sn to these layers increases ESR, compromising device performance.

Innovation Solution

A multilayer structure is designed with internal electrode layers where the Sn concentration gradually increases from the center to the outermost edge, enhancing resistance to humidity while maintaining mechanical strength and reducing ESR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the internal electrode layers are made thin to increase the number of stacked layers, then the capacity per unit thickness increases, but the internal electrode layers become easily broken during firing

Engineering Contradiction:

Improvenumber of stacked layers per thickness unitVSAvoidmechanical strength of internal electrode layers

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent applies local quality by creating a gradient Sn concentration distribution within the internal electrode layers, where the Sn concentration varies from the outer surface toward the inner portion. This localized variation in composition provides enhanced breaking resistance at critical regions while maintaining overall thin layer structure, resolving the contradiction between thin layer design and mechanical strength.

Inventive Principle:

Principle #3Local quality

2Reliability

If Sn is added to the internal electrode layers to improve resistance to humidity, then resistance to humidity improves, but ESR becomes larger

Engineering Contradiction:

Improveresistance to humidityVSAvoidESR (Equivalent Series Resistance)

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a gradient Sn concentration distribution within the internal electrode layers, where the Sn concentration varies from the outer surface toward the inner portion. This localized variation in composition provides enhanced breaking resistance at critical regions while maintaining overall thin layer structure, resolving the contradiction between thin layer design and mechanical strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by optimizing the Sn concentration gradient, specifically controlling the ratio of Sn concentration at the outer surface to Sn concentration at the inner portion to be within 0.5 to 2.0. This parameter optimization balances the competing requirements of humidity resistance and ESR control.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If the dielectric layers are made thin to increase capacity, then the capacity per single dielectric layer becomes larger, but insulation failure occurs more easily

Engineering Contradiction:

Improvecapacity per single dielectric layerVSAvoidinsulation performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming the gradient Sn concentration distribution in the internal electrode layers before final assembly. This preliminary optimization of electrode structure prevents moisture intrusion and subsequent insulation failure, protecting the thin dielectric layers from degradation before they can cause reliability issues.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12562315B2Ceramic electronic device including a multilayer structure with internal electrode layers having certain Sn concentration

Publication Date: 2026.02.24 TAIYO YUDEN KK

AI summary

A ceramic electronic device includes a multilayer structure in which each of a plurality of dielectric layers of which a main component is ceramic and each of three or more of internal electrode layers are alternately stacked. The three or more of internal electrode layers include Ni and Sn, wherein Sn is distributed entirely in the three or more of internal electrode layers. An internal electrode layer having a larger Sn concentration is closer to an outermost edge in a stacking direction than an internal electrode layer having a smaller Sn concentration and being located on a center side of the stacking direction, in a relationship of at least two of the three or more of internal electrode layers.