Abstract: A method for manufacturing a semiconductor integrated circuit device having contact apertures with finely-controlled dimensions of 1 .mu.m or less. An ion bombardment layer is formed by bombarding predetermined portions of the substrate of the semiconductor device with nitrogen ions using a direct ion beam imaging technique. The ion bombardment layer is converted into an oxidation-resistant layer by annealing, and an insulating oxide layer is formed on the surface of the substrate in regions other than those on which the oxidation-resistant layer is formed by oxidation. Thereafter, contact recesses are formed upon removing the oxidation-resistant layer.