Chemically amplified electron beam positive resist with acetal protecting group-effect of the additives on resist properties

We discuss a high-sensitivity electron beam (EB) positive resist based on acetal-protected poly(hydroxystyrene) (PHS) and also propose a new chemical amplification system. In this system, the generated acid after EB exposure acts as the catalyst for the deprotection reaction, as well as the water-generating reaction. This system can make the combination of acetal protecting group and strong acid possible in EB lithography.