Mechanism analysis of electric field and its application to aluminum corrosion in switch transistor

In this paper, by a group of electric-thermal cycle tests of NPN type switch transistors, the aluminum corrosion mechanism is demonstrated. And it was found that aluminum metal of chip surface was severely corroded under the high vapor and high electric field environment. It was analyzed that the electric field can accelerate aluminum corrosion. Under the electric filed, the main products of Al(OH)₃ hydrolyzation are negative state ions such AlCl₄ ^-, AlO₂ ^- and so on. The electric potential difference conduce the movement, emigration and distribution of aluminum corrosion resultants from low electric potential site (base board edge) to high electric potential site (equipotential rings).