Optical performances under the conditions of various geometrical structures and phase defects in phase edge PSM

Abstract

As high-speed non-memory devices require narrow gate widths ofless than 100 nm, the technology for this requirement should be guaranteed. In view of microlithography, one candidate to support such a narrow gate width is a phase edge (PE) PSM technique. However, because this PEPSM technique has not yet been thoroughly developed in the viewpoint of mask making, an activity to find optimal mask parameters for best optical performances should be made. In this paper, optical performances of PEPSM have been described under various geometrical structures and phase defects as mask parameters. Optical performances of PEPSM were strongly dependent on the pattern pitch, the optimal phase, and the mask structure. From our studies, the optimal phase of shifter was considered to be 179° and the optimal mask structure expressed in dry/wet etch ratio was 50/l300 when considering the overall pitch. The phase defect having its phase of less than 500did not seriously affect the lithographic patterning. We could easily make PEPSMs having maximum phase defects of 5Owith our hybrid etch process.Finally, we could build the manufacturing process of PEPSM for sub-100 nm resist CD patterning.