Electron Microscopic Research And Database Of Multilayer Ceramic Capacitor Reliability

Multilayer ceramic capacitor(MLCC) is an important electronic component. As MLCC used in military electronic equipment, the working environment had became more complex. To ensure the reliability of multilayer ceramic capacitors has become a pressing problem. In this paper, MLCC related quality problem was studied by the modern means of microscopic analysis(including scanning electron microscopy and X-ray energy dispersive spectroscopy), and the computer programming languages were used to developing the database software of multilayer ceramic capacitors.Ceramic dielectric powder and sintered ceramic were analyzed by secondary electron image mode, and lead-tin layer of end electrode was observed by backscattered electron image mode. Line and map scan of X-ray energy dispersive spectroscopy was used for analyzing the plating and dielectric breakdown location. Useful information was gained by the above analysis, and it was helpful to improve the quality of the products.The quality-related problems in end electrode of MLCC were analyzed, and it included the following three aspects: the end electrode contamination, weld failure and electroplating process. From the analysis results: the end electrode contamination was introduced by strontium bismuth titanate ceramics during the sintering process; the phenomenon of weld failure was caused by glass phase which overflowed from the end electrode; in the tin plating process, tin crystal varies by electroplating positions, and finally the right plating position has been found.For the crack branching phenomenon in inner electrodes, the inner electrodes, ceramic dielectric and silver end electrode paste were analyzed,and the formation mechanism had been discussed. The results showed that: the phenomenon did not occur in the process of sample preparation or ceramic cutting, but in the process of silver paste sintering; 1187 silver paste had occurred the phenomenon at 800 and 850℃ ℃, but p212 silver paste had not occurred the phenomenon under different sintering temperature and combined well with the inner electrode; the matching between 1187 silver paste and ceramic dielectric was poor, and residual stress between the electrode and the ceramic dielectric was large, so the branching phenomenon was caused by the glass phase permeating.In the long-term microscopic analysis of multilayer ceramic capacitors, a large number of case reports were accumulated. In order to manage these reports more effectively, the object-oriented language C++, Structured Query Language(SQL) and Microsoft Foundation Class Library(MFC) were used to developing the database software of multilayer ceramic capacitors, in the environment of VC6.0 and SQL Server 2005. This software had achieved the function to reading, querying, deleting and modifying all reports.Through the above work, quality-related problems in end electrode of MLCC were analyzed deeply, and the problems in production process were solved effectively; the crack branching phenomenon in inner electrodes were discussed in detail, and the formation mechanism had been found; the computer programming languages were used to developing the database software of multilayer ceramic capacitors, this software has very high reference value by including a large number of cases.