Monolithic Ceramic Component Outer Electrode Plating Resistance
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Solution Overview
Problem
Monolithic ceramic electronic components, such as capacitors, face issues with reduced strength and reliability due to plating liquid penetration at the peripheral end portions of outer electrodes, leading to potential cracking and insufficient bending strength during reflow.
Innovation Solution
A monolithic ceramic electronic component with outer electrodes containing an inorganic substance like Si, where a crystal phase comprising Si, Ti, and Ba is formed at the interfaces with the ceramic layer, achieving a crystal phase area ratio of 75% to 98% within 5 μm from the peripheral end portions, which enhances plating liquid resistance and prevents ceramic elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outer electrodes are disposed to go around from end surfaces to side surfaces of the monolithic ceramic element, then electrical connection is achieved, but plating liquid penetrates into the interface between the ceramic element and outer electrodes causing reduced strength and reliability
Solution Approach 1:
A barrier layer is introduced as an intermediary substance between the outer electrode and the ceramic layer. This barrier layer specifically prevents plating liquid from penetrating into the interface region, while allowing the outer electrode to maintain its electrical connection function. The barrier layer acts as a mediator that blocks the harmful penetration path without interfering with the electrical conductivity of the electrode system.
Solution Approach 2:
The barrier layer is formed using a sacrificial organic substance that decomposes during the sintering process. This disposable approach allows the use of simple organic materials that provide temporary protection during manufacturing, then disappear to leave a clean interface without requiring complex permanent barrier structures.
2Reliability
If conventional electrically conductive paste containing metal resinate is used for outer electrode formation, then good plating liquid resistance is achieved, but product cost increases
Solution Approach 1:
The barrier layer uses inexpensive organic substances that are sacrificed during sintering to provide temporary protection against plating liquid penetration. This disposable approach replaces expensive metal resinate-based conductive pastes with cheaper organic materials that fulfill the barrier function during manufacturing but are consumed in the process.
Solution Approach 2:
The invention changes the chemical composition parameters of the interface region by introducing organic substances that decompose at sintering temperatures. This parameter change transforms the interface from being vulnerable to plating liquid penetration to having enhanced resistance, while using cost-effective organic materials instead of expensive metal resinate compounds.
3Reliability
If plating films are formed on outer electrodes to prevent solder leaching, then solderability is ensured, but ceramic constituents are eluted and bending strength becomes insufficient
Solution Approach 1:
The barrier layer serves as a protective intermediary between the ceramic layer and the plating films. It prevents plating liquid from reaching and eluting ceramic constituents at the interface, thereby maintaining the structural integrity and bending strength of the ceramic element while still allowing the plating films to provide their solderability function.
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 solution effectively suppresses plating liquid penetration and ceramic elution, resulting in a highly reliable monolithic ceramic electronic component with improved strength and reliability, reducing the likelihood of cracking and maintaining mechanical integrity.
Implementation Method 1
a crystal phase containing at least Si, Ti, and Ba is formed at the interfaces to the ceramic layer constituting the monolithic ceramic element in the peripheral end portions of the outer electrodes
Implementation Method 2
the value of the following crystal phase area ratio indicating the relationship between the area of the above-described crystal phase and the area of a glass phase, which are formed at the interface to the above-described ceramic layer
Data Source
AI summary
A monolithic ceramic electronic component having outer electrodes that include an inorganic substance containing at least Si, a crystal phase C containing at least Si, Ti, and Ba at the interfaces to a ceramic layer in peripheral end portions of the outer electrodes. A value of the crystal phase area ratio indicating the relationship between the area of the crystal phase C and the area of a glass phase G, which are formed at the interface to the ceramic layer, in a region within 5 μm from the peripheral end portion of the outer electrode is within a range of 75% to 98%.