Chemical amplification positive deep ultraviolet resist by means of partially tetrahydropyranyl-protected polyvinylphenol

Chemical amplification positive resists using tetrahydropyranyl-protected polyvinylphenol (THP-M) are investigated for deep-UV lithography. Infrared spectroscopy meansurements show that THP-M in the resist film cannot be completely deprotected by photogenerated acid. This causes a poor developability of the resist containing highly tetrahydropyranyl (THP) protected polyvinylphenol in an aqueous base developer. To improve the developability in the pure aqueous base developer, we use partially THP-protected polyvinylphenol. To determine the optimum protection degree, we examine the relation between the dissolution rate of THP-M films and THP-protection degree in developers. A resist formulated from 20% THP-protected polyvinylphenol and bis(tert-butylphenyl)iodonium triflate resolved 0.30-μm line-and-space patterns with the aqueous base development using a KrF excimer laser stepper with a dose of 46 mJ/cm 2 . Postexposure delay effects of this resist system are also studied. The deprotection reaction of THP-M for lower dose during the holding time at room temperature and incomplete deprotection reaction for higher dose are found to deteriorate the exposure characteristics.