To provide an anti-reflective organic substance which prevents the back reflection from lower film layers and eliminates standing waves that occur by changes in the thickness of photoresist and by light during a process for forming ultrafine patterns that use photoresist for lithography using 193 nm ArF, to provide an anti-reflective organic compound that can be used, especially, in the formation of the ultrafine patterns of 64M, 256M, 1G, and 4G DRAMs and a method for preparing the same, and to provide an anti-reflective film composition containing such anti-reflective organic compound, an anti- reflective film using the same, and a method for preparing the film.

There is provided a polymer compound having a structure of chemical formula (1) (wherein Ra and Rb are each hydrogen or methyl; R' and R" are each -H, -OH, -OCOCH3, -COOH, -CH2OH, or a 1-5C substituted or unsubstituted linear or branched alkyl or alkoxyalkyl; n is an integer of 1-5; and x and y are each a molar ratio of 0.01-0.99).