Liquid phase silylation process for 248-nm lithography using EL IR photoresist

The goal of this investigation was to develop a 0.3 micron silylation process for 248 nm exposure, using a commercial photoresist material. Presented are results from investigation into liquid silylation of 248 nm exposure of Dynachem EL IRTM, a non-melamine image reversal novalac material designed for i-line application. A GCA BOLD 0.42 NA, 248 nm excimer laser projection system was used for exposure. A process has been developed utilizing a silylation solution of hexamethyl- cyclotrisilazane (HMCTS), propylene-glycol-methyl-ether-acetate (PGMEA), and xylene mixtures. Using a 15 run Box-Behnken statistically designed experiment, dry development in 02 RIE has been optimized with chamber pressure, flow rate, and 02 flow as process factors. Process responses optimized were selectivity, etch rate, and anisotropy. Results show capabilities and sensitivities of the process. Response surfaces are presented, along with resist image results of 0.3 microns at 5:1 aspect ratio.