关键词: 多层陶瓷电容器, 失效分析, 电-热应力击穿, 氧空位迁移, 可靠性提升

Abstract: Aiming at the electro-thermal stress breakdown failure of multilayer ceramic capacitors (MLCCs), the failure modes and mechanisms are systematically analyzed, the corresponding analysis techniques are elaborated, and the reliability enhancement schemes are proposed. Electrical performance testing, metallographic microscopy, power-on screening and other technical means are comprehensively adopted. Combined with grinding and cross-sectional analysis, internal latent short-circuit defects are accurately located and their distribution characteristics are revealed. The research results indicate that the electro-thermal stress breakdown failure is mainly manifested as insulation degradation caused by ion migration in dielectric layers and oxygen vacancy enrichment. In particular, the failure risk of ultra-thin-layer type MLCCs with dielectric layer thickness of ≤0.6 μm increases significantly under overvoltage conditions. The failure rate of MLCCs can be effectively reduced by optimizing core manufacturing processes, improving circuit design, and adopting flexible terminal electrode structures. As verified by application cases, the introduction of flexible terminal electrode structures and the optimized PCB thermal design reduce the failure rate of conventional MLCCs in high-temperature environments from 0.5% to 0.01%, and product reliability is significantly improved.

Key words: multilayer ceramic capacitor, failure analysis, electro-thermal stress breakdown, oxygen vacancy migration, reliability enhancement