Thickened Peripheral Electrode in Ceramic Components
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Solution Overview
Problem
The existing methods for forming external terminal electrodes in ceramic electronic components, such as multilayer ceramic substrates, often result in decreased bonding strength due to uneven thickness distribution, which leads to peeling and reduced adhesion, and the use of sintering inhibitors causes stress and deformation during firing.
Innovation Solution
A ceramic electronic component design where the peripheral portion of the external terminal electrode is thicker than the center portion and buried within the component main body, with an electrically insulating coating layer covering the peripheral portion, and a plating film applied to enhance bonding strength, while the manufacturing method involves separate formation of the peripheral and center portions using conductive pastes with varying compositions to prevent surface tension issues and improve printability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conductive paste is printed on the ceramic green sheet by means of screen printing, then the external terminal electrode is formed, but the conductive paste gathers at the center portion due to surface tension and the thickness of the peripheral portion is decreased
Solution Approach 1:
The patent applies local quality by making the peripheral portion of the external terminal electrode thicker than the center portion. This non-uniform thickness distribution is designed to provide enhanced bonding strength at the peripheral portion where stress concentration occurs, while maintaining adequate conductivity at the center portion for electrical connection.
Solution Approach 2:
The patent introduces asymmetry in the thickness profile of the external terminal electrode, creating a deliberately non-symmetric structure where the peripheral portion has greater thickness than the center portion. This asymmetric design addresses the stress distribution pattern that is higher at the periphery during mounting and operation.
2Strength
If printing of the conductive paste is repeated by screen printing to increase the thickness of the peripheral portion, then the bonding strength is improved, but the adhesiveness between the screen printing plate and the conductive paste film is deteriorated and the printability is deteriorated
Solution Approach 1:
The patent applies preliminary action by forming a first external terminal electrode with a specific thick peripheral portion before forming the second external terminal electrode. This pre-established thick peripheral structure provides the necessary bonding strength foundation, allowing the second electrode to be formed with standard printing processes without requiring repeated printing that would cause paste accumulation and printability deterioration.
3Strength
If the thickness of the external terminal electrode is increased to improve bonding strength, then the bonding strength is improved, but stress caused due to difference in shrinkage behavior between the external terminal electrode and the component main body is increased and deformation such as warp and waviness occurs
Solution Approach 1:
The patent applies local quality by concentrating the increased thickness specifically at the peripheral portion of the external terminal electrode, while keeping the center portion thickness moderate. This localized thickening provides enhanced bonding strength where stress concentration occurs during mounting, while avoiding excessive overall thickness that would cause significant shrinkage mismatch and deformation of the component main body.
4Ease of manufacture
If the thickness of the peripheral portion of the external terminal electrode is decreased, then the manufacturing process is simpler, but the external terminal electrode easily peels off from the component main body
Solution Approach 1:
The patent applies local quality by making the peripheral portion of the external terminal electrode thicker than the center portion. This non-uniform thickness distribution is designed to provide enhanced bonding strength at the peripheral portion where stress concentration occurs, while maintaining adequate conductivity at the center portion for electrical connection.
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
This configuration significantly enhances the bonding strength of the external terminal electrode, reduces the likelihood of plating solution infiltration, and minimizes undesirable deformation by managing stress and shrinkage differences between the electrode and the component main body.
Implementation Method 1
the conductive paste adheres to and remains at the side surface of an opening in a transmission portion of a screen printing plate
Implementation Method 2
pressing the ceramic green sheets
Implementation Method 3
firing the ceramic green sheets
Data Source
AI summary
In an electronic component, a peripheral portion of an external terminal electrode is thicker than a center portion thereof, and at least a portion of the peripheral portion is buried in a component main body. A surface of the external terminal electrode and a principal surface of the component main body are located on the same plane. An electrically insulating coating layer is arranged along the principal surface of the component main body so as to cover at least a portion of the peripheral portion of the external terminal electrode. An end portion of the coating layer is in contact with a thickest portion of the peripheral portion of the external terminal electrode in the principal surface of the component main body. The coating layer and the surface of the external terminal electrode are located on the same plane.