A high resolution negative electron resist by image reversal

The use of AZ 1350 family photoresists as negative electron resists is described. Conventional photolithographic technology is used to coat and process the resist, with the exception of an e-beam exposure for patterning. A flood UV exposure is used for image reversal. Using 1.5 µm initial thickness, the exposure threshold for 6 s development in 1 : 1 AZ : H2O developer is 7 µC/cm². The resist contrast under these conditions is 1.3; and the sensitivity is about 25 µC/cm²(70% thickness remaining). Useful resolution on SiO2/Si and Al/SiO2/Si substrates is demonstrated to be at least 0.5 µm, and the resist is shown to mask the plasma etching of Al.