Inaccuracies of the LTCC technology and their impact on the chip balun performance

This paper describes a case study of an impact of inaccuracies that arise in the LTCC technology on electrical parameters of a chip LTCC balun. The motivation behind this work was to identify stages of the LTCC process that contribute the most to the performance degradation of LTCC devices. We used optical microscopy and X-ray CT (X-ray Computed Tomography) scanning of the balun structure before and after sintering process, respectively. We also made a sensitivity analysis of the balun parameters by means of computer simulation. The results of this analysis were correlated with inaccuracies that were found before. We have learnt that the balun performance degradation result mainly from misalignment of layers during lamination process and poor calibration of a laser cutting tool used for metallization patterning. The outcome of our study may be useful, as a practical guide, to designers developing chip LTCC devices.