The present invention relates to organic anti-reflective coating polymers suitable for use in a semiconductor device during a photolithograhy process for forming ultrafine patterns using 193 nm ArF beam radiation, and preparation method therefor. Anti-reflective coating polymers of the present invention contain a monomer having a pendant phenyl group having high absorbency at the 193 nm wavelength. When the polymers of the present invention are used in an anti-reflective coating in a photolithography process for forming ultrafine patterns, the polymers eliminate the standing waves caused by changes in the thickness of the overlying photosensitive film, by the spectroscopic property of lower layers on wafer and by changes in CD due to diffractive and reflective light originating from the lower layers. Use of the anti-reflective coating of the present invention results in the stable formation of ultrafine patters suitable for 64M, 256M, 1G, 4G and 16G DRAM semiconductor devices and a great improvement in the production yield.The present invention also relates to anti-reflective coating compositions containing these polymers and to the anti-reflective coatings formed from these compositions, as well as preparation methods therefor.