I-line lithography for subhalf-micron design rules

Abstract

I-line lithography, together with single-layer resist processes, practically, have been limited to 0.45 micrometers design rules in the semiconductor industry. For design rules of 0.4 micrometers and below, several contrast enhanced methods have been proposed for i-line lithography, mainly phase shift masks, modified illumination methods, and surface imaging techniques, etc. This paper describes the sub-half micron process performance of 0.48 NA and 0.54 i-line steppers on various topography wafers which are suitable for 0.35 - 0.40 micrometers and 0.40 - 0.45 micrometers design rules. The latest high performance i-line resist and high contrast developing scheme have been chosen for this study. The process windows for the sub-half micron features on various topography wafers are reported. The feasibility to use these processes for the production with lower K 1 is also addressed.