Negative resist based on phenol protection.

Abstract

Negative resistsystem, consisting of organic polyhalides and poly(hydroxystyrene), has been examined for KrF excimer laser lithography. Several trichloromethylated 1, 3, 5-triazines and trichloromethylated benzenes are suitable to the photoactive compounds for this system. The resist using trichloromethylated benzene has a sensitivity of 66mJ/cm2 to KrF excimer laser and a resolution of 0.38μm.The insolubilization mechanism of this system has been clarified. Hydroxyl groups of poly(hydroxysyrene) are protected with the acyl groups derived from trichloromethyl groups of photoactive polyhalides under deep UV irradiation. The polarity change caused by the conversion of poly(hydroxystyrene) to the esterified derivative. Insolubilization in an alkaline solution of the exposed area of the resist film is based on such phenol protection reaction.