Hardware upgrades in immersion lithography
IMECs ASML XT:1250i step-and-scan system has been upgraded with state-of-the-art hardware. The first exposures show excellent performance in three key areas: improved CD uniformity across the wafer, better overlay numbers up to values comparable to dry 193nm lithography, and a reduction in patterned defectivity.
IMEC has since presented the first conclusive exposure results on its recently upgraded ASML XT:1250i immersion lithography tool. CD uniformity across the wafer is about two times better as compared with results obtained with the first generation immersion hardware. This is due to scanning over the edge with improved focus control.
Overlay performance was improved to comparable numbers as dry 193nm lithography, thanks to the new ASML stage design. Defectivity data showed a spectacular reduction in number of defects, going down to 0.037 defects per square centimetre. These results were obtained in the framework of the IMEC Industrial Affiliation Programme on immersion lithography, which unites more than 30 major players in the field of immersion lithography.
'Our strategic partnership with ASML is a cornerstone of the IMEC Industrial Affiliation Programme on immersion lithography', said Luc Van den hove, Vice President Silicon Process and Device Technology. 'When the programme started one year ago we were able to provide our partners access to one of the first full-field step-and-scan systems from ASML'.
'We are very proud that we can show our partners these very positive results obtained on the upgraded system. They prove that the major critical issues for immersion lithography can be overcome making immersion a viable and manufacturable technology for the 45nm node.
