TOP SURFACE IMAGING PROCESS AT AND BELOW QUARTER-MICRON RESOLUTION AND PATTERN TRANSFER INTO METAL

The use of top surface imaging processes pushes the limits of both dee p ultraviolet lithography and e-beam direct writing. However, the flow effect due to silylation with monofunctional aminosilanes prevents th e creation of a faithful resist mask of a high resolution. The applica tion of mixed mono- and bifunctional agents causes crosslinking of the silylated resist and eliminates the flow, We investigated details of the silylation of novolak-based chemically amplified resists with a mi xture of bis(dimethylamino)methylsilane and dimethylsilydiethylamine. After mixing, new materials evolved until a stable ratio of all compon ents was reached. During silylation the ratio changes again and requir es a continuous adaptation of the silylation parameters. The optimized process enables the realization of a 0.15 mu m pattern in 0.7 mu m th ick resist. An inductively coupled plasma etcher was evaluated for tra nsferring of the resulting resist structures into typical aluminium al loys. The developed process enables the etching of subquarter-micron f eatures into 0.6 mu m thick AlSiCu layers. (C) 1997 American Vacuum So ciety.