NANOGLASS®E (NGE) ultra low-k (ULK) dielectric material, with a k-value of
∼2.2, was integrated for 130 nm Cu/ULK interconnect process technology. This
work deals with the characterization of reactive ion etching (RIE) and wet
chemical processing of this film. Blanket films were characterized for etch
rate, surface roughness, k-value change and chemical compatibility. Trench
etching and post etch wet clean processes were developed and optimized
enabling process integration for single damascene structures. Trench etch
processes were evaluated for two etch schemes viz., etching under - photo
resist and etching under hardmask. The details of each scheme will be
described and advantages observed will be discussed. To evaluate effect of
wet clean processes three different formulations were used. After formation
of single damascene wafers, metal comb and serpentine structures were
measured for metal continuity and bridging. Electrical continuity was
achieved for long serpentine structures with 0.18μm/0.18μm line
width/spacing. Based on voltage ramp test results the film was found to be
sensitive to certain plasma etch conditions.