| Popis: |
The design ofan organic material satisfying all ofthe requirements for a single layer photolithography resist at 157 nm is aformidable challenge. All known resists used for optical lithography at 193 nm or longer wavelengths are too highlyabsorbing at 157 nm to be used at film thicknesses greater than -9O nm. Our goal has been to identify potential, newphotoresist platforms that have good transparency at 157 nm (thickness normalized absorbance of2.5 rim' or less),acceptable plasma etch resistance, high Tg, and compatibility with conventional 0.26 N tetramethylammonium hydroxidedevelopers. We have been investigating partially fluorinated resins and copolymers containing transparent acidic groups aspotential 157 nm photoresist binders; a variety ofmaterials with promising initial sets ofproperties (transparency, etchresistance, solubility in aqueous TMAH) have been identified. Balancing these properties with imaging performance,however, remains a significant challenge.Keywords: 1 57 nm photoresists, fluoropolymers, etch resistance, transparency, tetrafluoroethylene, norbornene |
