The step-and-scan lithographic illumination system has a scanning slit which could not only control the exposure field size but also assist the wafer to complete scanning process with high uniformity. The scanning slit is comprised by four blades which are drive by four electric actuators. This paper presents a 193nm lithographic illumination system without utilizing scanning slit. A microlens array, a micromirror array and a collimating lens are used to generated a certain intensity distribution on the surface of the aperture array. A fast scanning mirror is used in to change the position of the formed intensity distribution to change the illuniated area on the mask. That can realize lithographic scanning process without slit.
The 193nm immersion lithographic machine has already achieved 22nm node and beyond, and its illuminator has become a polarized and off-axis illumination system. Illumination modes and polarization modes can be formed by different diffraction optical elements and polarization optical elements. This paper proposes a model including a micromirror array and a variable retarder array for forming freeform illumination mode and polarization mode. They can be achieved by controlling the retardations of the variable retarders and two-dimensional tilt angles of the micromirrors. The principles of the model are analyzed, and some equations are acquired. Circular illumination mode, tangential polarization modes have been obtained in the simulation experiments. The simulation results show the model is feasible for the 193 nm immersion lithography machine.