A hardmask polymer for a semiconductor device and a hardmask composition comprising the same are provided to form micropatterns of the semiconductor without any deformation of patterns by using a polyamic acid with excellent heat-resistance. A hardmask composition for forming micropatterns of a semiconductor device comprises a polyamic acid represented by the formula 1 or the formula 2 as a hardmask polymer. The composition further comprises a melamine-based cross-linking agent in an amount of 1-10 wt%, a thermal acid generator in an amount of 1-10 wt% and an organic solvent in a weight ratio of 2-80 times, based on the polyamic acid. Preferably, the melamine-based cross-linking agent is 2,4,6-tris(dimethoxymethylamino)-1,3,5-triazine, the thermal acid generator is 2-hydroxycyclohexylparatoluenylsulfonate and the organic solvent comprises at least one selected from gamma-butyrolactone, cyclohexanone and a mixture thereof.