Multilayer Ceramic Capacitor Selective Coating Removal
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges with moisture resistance and substrate mounting due to the formation of a water-repellent coating layer, which prevents solder bonding to the external electrode during mounting on a substrate.
Innovation Solution
A method of manufacturing multilayer ceramic capacitors involves forming a water-repellent coating layer on the ceramic body and external electrodes, with selective removal of the coating from the external electrode surfaces to enhance substrate mounting properties while maintaining moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-repellent coating layer is formed on the exterior of the capacitor to provide moisture resistance, then humidity resistance is improved, but solder bonding to the external electrode surface deteriorates
Solution Approach 1:
The patent applies different surface treatments to different regions of the external electrode. The coating layer is selectively removed from the solder bonding area to enable proper solder adhesion, while the coating layer is maintained on other areas of the external electrode and on the ceramic body to provide moisture protection. This local differentiation resolves the contradiction between needing coating for humidity resistance and needing bare metal surface for solder bonding.
2Reliability
If a water-repellent coating layer is formed on the external electrode to prevent moisture penetration, then moisture resistance at the junction between ceramic body and external electrode is improved, but substrate mounting properties deteriorate
Solution Approach 1:
The patent selectively removes the coating layer only from the portions of the external electrode that require solder bonding for substrate mounting, while maintaining the coating layer on other portions. This localized approach ensures that moisture protection is preserved where needed (at the junction between ceramic body and external electrode) while enabling proper solder bonding where required (on the exposed external electrode surface), thus resolving the contradiction between moisture resistance and substrate mounting properties.
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 approach improves humidity resistance and ensures direct solder bonding to the external electrode, enhancing substrate mounting performance and productivity by preventing moisture penetration at the junction between the ceramic body and external electrode.
Implementation Method 1
forming a water-repellent coating layer on a surface of a multilayer ceramic capacitor... effectively preventing moisture penetration at a junction between a ceramic body and an external electrode
Data Source
AI summary
A method of manufacturing a multilayer ceramic capacitor includes forming a water-repellent coating layer on surfaces of a multilayer ceramic capacitor having an internal electrode, a dielectric layer, and an external electrode; and removing at least a portion of the water-repellent coating layer formed on the surfaces of the external electrode such that another portion of the water-repellent coating layer remains on surfaces of the dielectric layer. The external electrode has first and second surfaces opposing each other in a thickness direction, third and fourth surfaces opposing each other in a width direction, and fifth and sixth surfaces opposing each other in a length direction.