Deoxidization of water desorbed from APCVD TEOS-O/sub 3/ SiO/sub 2/ by titanium cap layer

The water absorption and desorption characteristics of APCVD TEOS-O/sub 3/ SiO/sub 2/ have been studied by exposing SiO/sub 2/ films deposited at 380/spl deg/C in different O/sub 3/ concentrations to a water-vapor ambient. The total amount of water desorbed from the film decreased with the increasing O/sub 3/ concentration. In contrast, water desorbed from the film at temperature lower than 300/spl deg/C increased. In the application of TEOS-O/sub 3/ SiO/sub 2/ as an intermetal dielectric, water desorption at lower temperatures causes the bursting of via holes during high-temperature storage tests. It was found that, however, a thin titanium film deoxidizes water desorbed from TEOS-O/sub 3/ SiO/sub 2/ to hydrogen. The bursting of via holes was completely suppressed by using thin titanium film between the aluminum and TEOS-O/sub 3/ SiO/sub 2/ because hydrogen passes more easily than water through the aluminum interconnect.