Multilayer Ceramic Electrode Structure for Humidity Resistance

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Solution Overview

Problem

Thin internal electrode layers in ceramic electronic devices are prone to breaking during the firing process, leading to potential insulation failures due to moisture intrusion, especially when the dielectric layers are also thin.

Innovation Solution

A ceramic electronic device with a multilayer structure where internal electrode layers containing Ni and Sn are alternately stacked, with a higher Sn concentration closer to the outermost edge in the stacking direction, improving resistance to humidity while maintaining low Equivalent Series Resistance (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 unitVSAvoidbreaking resistance of internal electrode layers

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a gradient in Sn concentration across the internal electrode layers. The outermost internal electrode layers have higher Sn concentration (improving breaking resistance where stress is highest) while inner layers have lower Sn concentration (maintaining low ESR). This spatial variation in material composition resolves the contradiction between thin layer reliability and overall device performance.

Inventive Principle:

Principle #3Local quality

2Reliability

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

Engineering Contradiction:

Improveresistance to humidityVSAvoidESR (Equivalent Series Resistance)

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses local quality by concentrating Sn in the outermost internal electrode layers where humidity exposure is highest, while keeping Sn concentration low in inner layers. This spatial differentiation allows the device to achieve humidity resistance at the critical interfaces without incurring the ESR penalty throughout the entire electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the Sn concentration parameter across different positions in the internal electrode layers. The Sn concentration is changed from high in outer layers to low in inner layers, allowing optimization of both humidity resistance and ESR through parameter gradient rather than uniform composition.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12211653B2Ceramic electronic device and manufacturing method of the same

Publication Date: 2025.01.28 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 a plurality of internal electrode layers are alternately stacked. The plurality of internal electrode layers include Ni and Sn. Each of an upper section and a lower section of the plurality of internal electrode layers includes multiple internal electrode layers each having a Sn concentration higher than that of each internal electrode layer of a center section interposed between the upper and lower sections in a stacking direction, which are constituted by top 5% or more and bottom 5% or more of the plurality of internal electrode layers, respectively.