Experimental study on nonlinear multiple-exposure method

Non-linear multiple exposure (NOLMEX) method for forming a fine line and space pattern is described. The combination of the resist with non-linear photosensitivity and multiple exposures allows us to exceed the optical cut-off frequency, which has never been realized in the field of photolithography. In this paper, a new approach for NOLMEX method utilizing an ordinary resist instead of the non- linear resist is introduced. In the experimental results, 0.19 micrometers L/S pattern was resolved with a commercial i-line stepper using ordinary illumination, which indicates the potential of NOLMEX method.