Laminated Ceramic Capacitor Terminal Electrode Width Variation
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Solution Overview
Problem
Miniaturization of laminated ceramic capacitors to meet increasing demand for smaller electronic devices leads to reduced terminal electrode width, increasing the risk of undesirable exposure and short-circuit failures due to solder bridging, while attempts to increase electrode width for low ESL compromise manufacturing yield and reliability.
Innovation Solution
The design features terminal electrodes with an intermediate portion of larger width and end portions of smaller width, which reduces the risk of solder bridging and maintains a sufficient distance between adjacent electrodes, while the intermediate portion's wider width aids in reducing ESL and preventing internal electrode exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode width of terminal electrodes is increased to reduce ESL and prevent exposure of internal electrodes, then the reliability and manufacturing yield improve, but the pitch between adjacent terminal electrodes decreases, increasing the risk of solder bridging and short-circuit failure
Solution Approach 1:
The terminal electrode is designed with non-uniform width along its length: wider at the intermediate portion (covering the led-out portion of internal electrode) and narrower at the end portion (exposed on the side face). This local variation in width allows the electrode to perform different functions in different regions, resolving the contradiction between preventing exposure and avoiding solder bridging.
2Reliability
If the electrode width of terminal electrodes is increased to reduce ESL, then the high-frequency characteristic improves, but the pitch between adjacent terminal electrodes decreases, increasing the risk of short-circuit failure
Solution Approach 1:
The terminal electrode has a width that varies along its length, being wider at the intermediate portion and narrower at the end portion. This allows the electrode to provide low ESL through the wider intermediate section while maintaining safe pitch between adjacent electrodes through the narrower end sections, thus improving high-frequency characteristics without increasing short-circuit risk.
3Productivity
If the electrode width of terminal electrodes is increased to prevent undesirable exposure of internal electrodes, then the manufacturing yield improves, but the pitch between adjacent terminal electrodes decreases, increasing the risk of solder bridging
Solution Approach 1:
The terminal electrode is designed with a wider intermediate portion that adequately covers the led-out portion of the internal electrode, preventing exposure and ensuring manufacturing yield. The end portion is narrower, exposing only a small area on the side face, which maintains sufficient pitch between adjacent electrodes and reduces solder bridging risk.
Data Source
AI summary
A laminated ceramic capacitor includes a body having an inner layer portion and an outer layer portion and a plurality of terminal electrodes spaced apart from each other in a length direction of the body. The inner layer portion has a plurality of internal electrodes stacked in a height direction of the body. The internal electrodes have led-out portions led out to a side face of the body. The outer layer portion is disposed on one of opposite faces of the inner layer portion in the height direction. Each terminal electrode extends along the height direction to cover corresponding one of the led-out portions and is provided with an intermediate portion and an end portion. The intermediate portion has a larger electrode width than the led-out portion. The end portion has a smaller electrode width at an edge of the side face than the intermediate portion.