Multilayer Ceramic Capacitor Resistive Layer Thickness Control

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Solution Overview

Problem

Multilayer ceramic capacitors experience significant variations in resistance due to the thickness variations of glass paste-based resistive layers, leading to unacceptable performance in applications requiring power saving, where small voltage changes result in large current changes.

Innovation Solution

A multilayer ceramic capacitor design with a first metallic layer having a higher specific resistance than the second metallic layer, where the difference in thickness between the outermost and center portions of the first metallic layer is minimized to 5 μm or less, formed by using a conductive sheet and conductive paste, ensuring consistent resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a glass paste is applied to form a resistive layer, then the resistive layer can be formed on the laminate, but the thickness of the glass layer varies due to viscosity variation and drying degree variation, causing resistance variation

Engineering Contradiction:

Improveease of forming resistive layerVSAvoidthickness uniformity of resistive layer

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from glass paste to conductive sheet material, and controls the thickness parameter by pressing the sheet to achieve uniform thickness of 5 μm or less, eliminating the viscosity and drying degree variation problems inherent in paste application

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the chemical/physical process of paste application and drying with a mechanical pressing process, where a conductive sheet is pressed onto the laminate to form the resistive layer, providing better thickness control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the resistive layer thickness varies, then the manufacturing process is simpler, but the resistance varies significantly, making the capacitor unacceptable for power-saving applications

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidresistance consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses hydraulic or pneumatic pressing to apply uniform pressure across the conductive sheet, ensuring consistent thickness and resistance values while maintaining efficient production

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the formation method parameter from paste application to sheet pressing, and controls the thickness parameter to 5 μm or less, achieving both high productivity and reliable resistance consistency

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10515762B2Electronic component including a resistive layer

Publication Date: 2019.12.24 MURATA MFG CO LTD

AI summary

An electronic component includes a laminate including dielectric layers and internal electrode layers stacked in a lamination direction. A first external electrode is on a first end surface of the laminate, and connected with a first of the internal electrode layers. A second external electrode is on a second end surface of the laminate, and connected with a second of the internal electrode layers. The first external electrode includes a first metallic layer connected to the first internal electrode layer, and a second metallic layer disposed on the first metallic layer. The first metallic layer has a higher specific resistance than the second metallic layer, and a difference between a thickness of an outermost portion of the first metallic layer in the lamination direction and a thickness of a center portion of the first metallic layer in a center in the lamination direction is about 5 μm or less.