Chemically Amplified Resists

Organic Materials Challenges for 193 nm Imaging

“…Consequently, 193 nm resists could be designed using the same PAGs as those that are in use with 248 nm resists. In addition to absorption, the considerations in designing a PAG are solubility, volatility of both the PAG and its photoproducts, acid strength, cost, and toxicity 5c. For tert- butyl-substituted materials, high acid strength (often superacids are required) and high postexposure bake (PEB) temperatures are required for complete removal of the ester appendage.…”

“…Additionally, high glass transition temperature ( T g ) polymers based on N-blocked maleimide/styrene resins and substituted styrene-sulfone copolymers have been explored . Notably, the first commercially available positive 248 nm resist was introduced in 1990 after almost 10 years of research, and was based on the copolymer derived from tert -butoxycarbonyloxystyrene and sulfur dioxide used in conjunction with a nitrobenzyl tosylate photoacid generator material …”

Lithographic Resist Materials Chemistry

“…Examp les include poly(hy droxystyrene) (109), poly(vinyl benzoate) (157), poly(methacrylic acid) (153), N-blocked malei mide/styrene resins (158,159), and poly(hy droxyphenyl methacrylat e) (160). A matrix polymer that combines the advantages of chemically amplified deprotection with conventional chain scission processes is poly( 4-t-butoxy carb onyloxystyrene-sulfone) (PTBSS) (161,162). As in the case of PTBS, the t-butoxycarbonyl moiety is used as the acid-labile protective group.…”