Practical evaluation of 16M-DRAMs production with i-line phase-shift lithography

摘要

Abstract: We have fabricated 16M-DRAMs with i-line phase-shift lithography using 8 inch wafers. Edge-contrast enhancement type was used as a phase-shift reticle. The effects on i-line phase-shift lithography were evaluated for the patterns which have a small focus and alignment margin. It was found that the phase-shift lithography has a large effect on enlarging focus margin of small size patterns like 0.5 $mu@m. We evaluated the effect of phase- shift lithography by a trial manufacturing of 16M-DRAMs. As a result, i-line phase-shift lithography was found to have a possibility of high yield production of 16M-DRAMs. However, it was also found that there were several rejected pattern widths which were caused by variation of shifter width in the phase- shift reticle. So it is necessary to improve these rejected patterns for the application of this method to 16M-DRAMs.!4