Investigation on electromigration failure of phase shifter

Aiming at the problem of electric loss rises, the qualified and the failed phase shifters were employed for comparative analysis in this paper. The morphology and micro-composition after chemical unsealing were analyzed by using scanning electron microscope and electron probe energy disperse spectroscopy. The comparative results showed that the plastic surface of the capacitor near the output was obviously covered by the dendritic branches of metal atoms in the failed sample, causing the capacitor short-circuited. Combined with the production process, the failure reason was closely linked to the unqualified leakage problem near the two outputs. Further observation of the insulator in the output was conducted to reveal that the interface structure between glass matter and kovar alloy was non densification, and the crystalline of glass phase and gaps existing were also found. Therefore moisture as the medium entering from the weakness position into the cavity made metal migrated. On based of that, the corresponding improvements have been proposed to greatly suppress it.