Erdelyi, MiklosBor, ZsoltSzabo, GaborCavallaro, Joseph R.Smayling, Michael C.Tittel, Frank K.Wilson, William L.2012-06-152012-06-151996-03-01M. Erdelyi, Z. Bor, G. Szabo, J. R. Cavallaro, M. C. Smayling, F. K. Tittel and W. L. Wilson, "Sub-quarter micron contact hole fabrication using annular illumination," 1996.http://scholar.google.com/scholar?cluster=13023915854796936665&hl=en&as_sdt=0,44https://hdl.handle.net/1911/64278Details of an experimental demonstration of a contact hole imaging system are reported in which the depth of focus is increased by a factor of about 3.5 using annular illumination. Due to spatial filtering and nonlinearity of the photoresist, the resolving power was enhanced by 52% and it was possible to pattern a 0.28 um contact hole in photoresist deposited on a silica substrate. This technique is capable of fabricating sub-quarter micron holes using excimer laser radiation at 193 nm.engConference paper