A method and apparatus for depositing a low
dielectric constant film by reaction of an
organosilicon compound and an oxidizing gas at a constant RF
power level from about 10W to about 200W or a pulsed RF
power level from about 20W to about 500W. Dissociation of the oxidizing gas can be increased prior to mixing with the
organosilicon compound, preferably within a separate
microwave chamber, to assist in controlling the carbon content of the deposited film. The oxidized organosilane or organosiloxane film has good barrier properties for use as a liner or cap layer adjacent other
dielectric layers. The oxidized organosilane or organosiloxane film may also be used as an etch stop and an intermetal
dielectric layer for fabricating dual damascene structures. The oxidized organosilane or organosiloxane films also provide excellent adhesion between different dielectric
layers. A preferred oxidized organosilane film is produced by reaction of
methylsilane, CH3SiH3,
dimethylsilane, (CH3)2SiH2, or 1,1,3,3-tetramethyl-
disiloxane, (CH3)2-SiH-O-SiH-(CH3)2, and
nitrous oxide, N2O, at a constant RF
power level from about 10W to about 150W, or a pulsed RF power level from about 20W to about 250W during 10% to 30% of the
duty cycle.