MLCC Groove Design for Oxidation-Resistant Electrode Contact
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Solution Overview
Problem
In multi-layer ceramic capacitors, electrical conduction between internal and external electrodes can be inhibited due to oxidation, and existing methods to address this, such as chemical solution removal or polishing, often lower capacitor performance due to residual chemicals or debris.
Innovation Solution
The capacitors feature ceramic bodies with internal electrodes protruding into grooves on the end surfaces, ensuring electrical connection even if the electrodes are oxidized, and the use of short-pulse laser to form these grooves without a wet process, allowing for reliable conduction and increased capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical solution or polishing is used to remove oxidized end portions of internal electrodes, then electrical conduction is improved, but capacitor performance is lowered due to residual chemicals or debris
Solution Approach 1:
The patent extracts the harmful oxidized portions of internal electrodes by forming grooves that remove the oxidized end portions, allowing the fresh, non-oxidized electrode material to contact the external electrodes and solder, thereby eliminating the need for chemical solutions or polishing that leave harmful residues
Solution Approach 2:
The patent replaces the chemical/mechanical removal process (chemical solutions or polishing) with a groove formation process that physically exposes fresh electrode material through mechanical or laser-based groove formation, avoiding the introduction of harmful residues
2Ease of manufacture
If internal electrodes are oxidized during sintering, then sintering process is simplified, but electrical conduction between internal and external electrodes is inhibited
Solution Approach 1:
The patent performs preliminary groove formation after sintering to expose fresh electrode material before the electrical connection is finalized, allowing the sintering process to proceed without special anti-oxidation measures while still ensuring good electrical contact in the final product
Solution Approach 2:
The patent applies local quality by creating grooves only at specific locations where internal electrodes contact external electrodes, leaving the rest of the electrode structure intact and maintaining the simplified sintering process while improving electrical conduction at critical interfaces
3Reliability
If grooves are formed in end surfaces to expose internal electrodes, then electrical conduction is ensured, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical groove formation with laser beam processing, which can precisely form grooves without mechanical contact, reducing tooling complexity and enabling flexible groove patterns while ensuring reliable electrical conduction
4Ease of manufacture
If conventional electrode connection methods are used, then manufacturing is simpler, but connection strength is reduced due to oxidation
Solution Approach 1:
The patent extracts the oxidized, weak connection layer by forming grooves that remove the oxidized end portions of internal electrodes, allowing fresh, non-oxidized electrode material to contact the external electrodes and solder, thereby significantly improving connection strength while maintaining ease of manufacture
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 ensures reliable electrical conduction between internal and external electrodes, enhances connection strength through solder wetting, and increases capacitance without using wet processes, thus improving the overall performance of the capacitors.
Implementation Method 1
forming a first inner groove in the first end surface of the sintered ceramic body and a second inner groove in the second end surface of the sintered ceramic body along the first direction by irradiation with short-pulse laser
Implementation Method 2
when the multi-layer ceramic capacitor is mounted, solder wets up along the first outer groove and the second outer groove
Data Source
AI summary
A multi-layer ceramic capacitor includes a ceramic body, a first external electrode, and a second external electrode. The ceramic body includes ceramic layers laminated along a first direction, first internal electrodes and second internal electrodes that are alternately disposed between the ceramic layers, a first end surface and a second end surface that are oriented in a second direction orthogonal to the first direction, and a first inner groove and a second inner groove that are respectively formed in the first end surface and the second end surface along the first direction. The first and second external electrodes respectively cover the first and second end surfaces, the first internal electrodes being drawn to the first end surface and protruding in the first inner groove, the second internal electrodes being drawn to the second end surface and protruding in the second inner groove.