A double exposure using mutually one-pitch-step shifted alt. PSM's is proposed to eliminate the LICD and CD reversal. By doubly exposing mutually one-pitch-step shifted alt. PSM's, the LICD and CD reversal is observed to disappear. The phase and undercut margins of 8° and 40 nm are observed, respectively by simulation for 1 .2 jim DOF margin. The alignment tolerance is calculated to be 75 nm which is enough for considerring recent lithographic systems. By doubly exposing mutually one-pitch-step shifted alt. PSM, almost identical CD's of 141 nm and 142 nm are measured. The phase margin of 15 0 (from 169° to 184°) and the undercut margin of 50 nm (from 100 nm to 150 nm) are observed for DOF margin of 1.0 rim. Our double exposing technique prove to have advantages over alt. PSM not only in removal of LICD and CD reversal, but also in the phase and undercut margin.