Abstract: An aging process that makes SiNx single-layer halftone film stable for DUV (248 nm) exposure has been established. The light irradiation with a low pressure mercury lamp was used to age the SiNx halftone film from the tendency of the transmittance change caused by the DUV exposure. Taking account of the optical constants shift during aging process, a SiNx halftone film with transmittance T $EQ 9.3%, phase shift angle $theta $EQ 178 degrees was obtained. At the SiNx film, no transmittance change was observed after 2800 J/cm$+2$/ DUV exposure. Using the mask, 0.2 $mu@m hole patterns were obtained with above 1.0 $mu@m depth of focus (DOF).!8
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