Any guru who’d predicted this some years ago would have been laughed out of the industry. ASML’s latest 193nm Twinscan XT:1250 stepper makes little incremental improvements to get ordinary old optical lithography down to 70nm half-pitch line resolution with ordinary old binary masks — for ordinary old 200mm fabs, as well as 300mm.
The company also showed not-so-bad 85nm resolution on contact holes with alternating phase shift masks, and said development work with MaskTools’s chromeless phase lithography masks showed potential for 65nm contact holes.
“We now see more and more interest from 200mm fabs for the most advanced technology too, so this is especially for 200mm fabs,” said Paul van Attekum, senior VP of marketing and technology, in the company’s conference call announcing the new tool. “For some customers it’s a matter of survival. Or some just see the opportunity for added life for their old fabs.” He said ASML had initial orders for the tool for both 200mm and 300mm fabs for shipment in 2Q04. Production leadtime is about six months.
The stepper’s footprint is reduced 25% to meet 200mm fab space requirements by putting a section of the tool in a separate module that can go outside the cleanroom. Facility requirements for water and gas and the like are likewise reduced to levels available in older fabs.
Though the lens NA remains unchanged, ASML says improved metrology and the like tightened its detailed specifications. It increased stage speed, and now includes its full ultra k porfolio of tweaking software enhancements and the like as a commercial, not development, product. “Most of the work was for improving the overlay,” said van Attekum. “Some 50-70 things had to be tuned and optimized.” He says overlay is less than 10nm for the same machine, 14nm for different ones. — Paula Doe, European Editor