Research on high-quality projecting reduction lithography system based on digital mask technique

In this paper, digital mask technique is presented, and a high-quality projecting reduction lithography system has been set up successfully. The core device of digital mask technique is digital micromirror device (DMD) which belongs to one of the electrically addressed spatial light modulators. The output image of DMD can be equivalent to a gray-scale mask of high precision, which can control the exposure precisely. If it is combined with a high-quality projecting reduction system, the fabrication of submicron diffractive optical elements can be realized successfully. The overall design of the system is described in detail, and some diffractive optical element masks are fabricated. Experimental results verify that the system is feasible. In the end, system characteristics and system error are summarized.