Asao Isobe

A Series Of Azide-Phenolic Resin Resists For The Range Of Deep UV To Visible Light

A series of new type of negative photoresists composed of a phenolic resin and azide sensitizers has been developed. RD-2000N is sensitive in the deep UV region, RU-1000N in the mid UV region and RG-3000N in the mid UV to visible region. These resists are non-swelling aqueous developable, and give higher resolution compared to conventional cyclic rubber based negative resists. Resolution in less than 1 μm can be obtained by 1 : 1 projection or 10 : 1 reduction projection aligning method. Adequate exposure doses to define submicron patterns are 50 mJ/cm4(at 254nm),70 mJ/cm° (at 365 nm) and 180 mJ/cm2(at 436nm) for RD-2000N, RU-1000N and RG-3000N, respectively. The resistance to dry etch gases is also superior to conventional negative resists, and comparable with novolak resin based positive resists. Intense absorption of irradiating light by these resists makes them insensitive to reflected light from the substrate, resulting in a high resolution on stepped substrates without any antireflective layers which are necessary in positive resist applications.