Corrosion Problems in ULSI's

Various problems concerning corrosion in ULSI (Ultra-large-scale Integration)'s are discussed. After a brief discussion on Al-line corrosion in plastic packages, two problems connected with ULSI manufacturing are explained and discussed. One is the selection of heat treatment atmosphere which does not oxidize tungsten gate electrodes, but can oxidize silicon at the same time. The other is the high-temperature stability of thin SiO2 films in refractory metal/SiO2/Si structures. Namely, the degradation of SiO2 occurs by H2 atmosphere and by the reaction between SiO2 and Si.