Mechanism analysis of aluminum corrosion and its application to switch transistor

In this paper, aluminum corrosion mechanism in switch transistor was analyzed. And a group of NPN type switch transistors contrast electric-thermal cycle tests of whether it is vapor control, passivation protection, equipotential rings exist, and clearance enhancement before package were carried out, respectively. By contrast tests, the aluminum corrosion mechanisms are analyzed. Effects of temperature, moisture (vapor), voltage (electric field) and ion contamination on aluminum corrosion occurrence and degree and speed are analyzed too. As well as the aluminum corrosion configurations, distributions, and related factors are analyzed. Finally, the best measure to control aluminum corrosion through control interior vapor to insulate the necessary condition of corrosion occurrence was recommended.