0.7 NA DUV Step & Scan system for 150nm imaging with improved overlay

To extend KrF lithography below the 180nm SIA design rule node in manufacturing, an advanced DUV Step & Scan system utilizing a lens with an NA up to 0.7 will be required to provide sufficient process latitude [1]. Towards the SIA's 150nm design rule node, manufacturing challenges for 248nm lithography include contact hole printing, iso-dense bias control and adequate across the field CD uniformity. All will benefit from higher NA lenses. In this paper, results obtained on a PAS 5500/700B DUV Step & Scan system are presented. The system design is based on the PAS 5500/500([2, 3]) with a new 0.7NA Starlith(TM) lens, AERIAL(TM) II illuminator and ATHENA advanced alignment system. Imaging of dense and isolated lines at 180nm, 150nm and below as well as 180nm and 160nm contact holes is shown. In addition to imaging performance, image plane deviation, system distortion fingerprints, single-machine overlay and multiple-machine matching results are shown. Using the ATHENA alignment system, alignment reproducibility as well as overlay results on CMP wafers will be shown: It is concluded that this exposure tool is capable of delivering imaging and overlay performance required for mass production at the 150nm design rule node, with potential for R&D applications beyond.