<title>Polyvinylphenols protected with tetrahydropyranyl group in chemical amplification positive deep-UV resist systems</title>

Abstract

Tetrahydropyranyl(THP) protected poly(p-vinylphenol)s were synthesized and their acid-catalyzed thermal deprotection has been utilized in the design of alkali developable, positive deep UV resist systems incorporating chemical amplification. Solubility of poly(p- tetrahydropyranyloxystyrene)(THP-M) films mixed with appropriate photoacid-generator (PAG) in alkaline developers increases upon exposure to deep UV radiation and subsequent heating. In a three component application where THP-M and PAG are mixed with a novolak resin, THP-M acts as an acid-labile dissolution inhibitor. Its dissolution inhibition ability was higher than that of a conventional photo-active dissolution inhibitor, diazonaphthoquinone. It is found that simple sulfonic esters such as 1,2,3-tri(methane sulfonyloxy) benzene (MeSB) are superior to onium salts in the three component approach because no negative tone side effect occurs when these esters are used as PAG. Fine patterns of 0.35 micrometers lines and spaces are obtained using KrF excimer laser steppers for the 3-component resists.