ACID-CATALYZED REACTIONS OF TETRAHYDROPYRANYL-PROTECTED POLYVINYLPHENOL IN A NOVOLAK-RESIN-BASED POSITIVE RESIST

This paper deals with an acid-catalyzed reaction mechanism of a polymeric dissolution inhibitor of a novolak-resin-based positive chemical amplification resist system. This resist system consists of a novolak matrix resin, tri(methanesulfonyloxy)benzene as an acid generator, and tetrahydropyranyl-protected polyvinylphenol (THP-M) as a polymeric dissolution inhibitor. The acid-catalyzed deprotection products of THP-M in the resist film are detected and their subsequent acid-catalyzed reactivities are evaluated. It is found that tetrahydropyranyl group are ''changed between THP-M and the matrix to yield a strong dissolution inhibitor, causing negative tone behavior at the overexposure dose. High-resolution patterns (0.3-mum contact holes) are achieved with high sensitivity (2.4 muC/cm2 at 50 kV).