Acid-amplifier having acetal group and photoresist composition including the same

By of exposure to the acid generated from the photo acid generator, which of the post-exposure bake process, to produce a secondary acid, and improving the line edge roughness of the photoresist pattern, to improve the energy sensitivity of the photoresist, an acetal group the photoresist composition containing the acid, and this amplification is started with. The acid amplifying agent has a structure of the following formula. In the formula, R has 4 to 20 carbon atoms or a single annular polycyclic saturated hydrocarbon group in which p is 1 to 100; R Photoresist, a photosensitive compound, a photo acid generator