193-NM LITHOGRAPHY AT MIT LINCOLN LAB

Over the past 20 years, the image-resolution capability of optical lit hography has progressed from 2 mu m to better than 0.5 mu m. This rema rkable advance was made possible by improved lens quality, lenses of i ncreased numerical aperture (NA), and the use of shorter exposure wave lengths. Currently, wavelengths of 365 or 248 nm are used for imaging minimum feature sizes, but as dimensional requirements on features dro p below 0.25 mu m in the next few years, it will be necessary to consi der the use of even shorter exposure wavelengths. One obvious candidat e, 193 nm, happens to be the emission wavelength of the argon fluoride excimer laser.