BaF Coated Multilayer Ceramic Capacitor Electrode Formation
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Solution Overview
Problem
The challenge is to form outer electrodes for electronic components like multilayer ceramic capacitors that are not arc-shaped, ensuring balanced shape and preventing the 'tombstone phenomenon' and cracks due to uneven conductive paste distribution, which occurs when low-viscosity conductive paste rises on side surfaces during the manufacturing process.
Innovation Solution
A method involving a rectangular multilayer body made of dielectric ceramic with inner electrodes, where a polymer coating film containing BaF is applied to the side surfaces, allowing immersion in a low-viscosity conductive paste to form linear-shaped outer electrodes, maintaining balance and preventing uneven paste distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If low-viscosity conductive paste is used to thin the outer electrodes, then the outer electrodes can be made thinner to increase the number of inner electrode layers, but the conductive paste rises unevenly on the side surfaces causing arc-shaped outer electrodes and shape variations
Solution Approach 1:
A coating film containing fluorocarbon resin is applied as an intermediary layer on the multilayer body surface before applying the conductive paste. This coating film acts as a mediator that controls the interaction between the conductive paste and the multilayer body, preventing uneven rising of the paste on the side surfaces while allowing proper adhesion to the end surfaces, thus achieving linear-shaped outer electrodes with uniform thickness.
2Shape
If the conductive paste rises unevenly on the side surfaces, then the outer electrodes become asymmetrical in shape, but this causes unbalanced tensile stress during soldering leading to the tombstone phenomenon
Solution Approach 1:
The coating film containing fluorocarbon resin serves as a controlled intermediary that ensures symmetrical and uniform application of conductive paste on both end surfaces. By preventing capillary action on the side surfaces while maintaining adhesion on the end surfaces, the coating film ensures that both outer electrodes have identical linear shapes, resulting in balanced tensile stress distribution during soldering and eliminating the tombstone phenomenon.
3Stress or pressure
If the outer electrodes are arc-shaped due to uneven paste distribution, then the tensile stress concentrates on the ridge portions, but this causes cracks in the multilayer body
Solution Approach 1:
The coating film containing fluorocarbon resin acts as a protective intermediary that prevents conductive paste from adhering to the side surfaces and ridge portions. This ensures that the outer electrodes have linear shapes with uniform stress distribution, preventing stress concentration at the ridge portions and eliminating the risk of cracks in the multilayer body during soldering and mounting processes.
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 results in outer electrodes that are linear-shaped, preventing asymmetrical formation and reducing the risk of the 'tombstone phenomenon and cracks, ensuring stable mounting and reduced stress on the component.
Implementation Method 1
the conductive paste tends to rise on side surfaces of the multilayer body in a short time due to surface tension
Implementation Method 2
forming an oleophobic coating film containing BaF on the surface of the multilayer body
Data Source
AI summary
A method for manufacturing an electronic component includes preparing a rectangular or substantially rectangular parallelepiped multilayer body made of dielectric ceramic containing Ti and Ba. The multilayer body includes inner electrodes embedded therein, a pair of opposite end surfaces, and four side surfaces connecting the end surfaces to each other. The method further includes forming an oleophobic coating film containing BaF on the surface of the multilayer body, and immersing the end surfaces of the multilayer body having the coating film formed thereon into a conductive paste having a viscosity of about 15 Pa·s or less.