Fabrication of small contacts is one of the most important challenges of semiconductor lithography. The use of Bessel contact, pupil filtering or phase shift mask has been suggested by various groups, however those were not easily applicable. Currently, only an attenuated has shift mask has been demonstrated as a useful enhancement approach for contact level lithography. As a practical pupil filtering method, a pellicle plane angular transmission filter is suggested. An angular transmission filter can be realized using multiple dielectric organic or inorganic coatings on glass or membrane substrates. Filter have been designed and fabricated for high NA DUV lithography and initial filter fabrication and exposure evaluation have been carried out. Lithographic results shown up to 20 percent improvement of minimum contact size for dense contacts, and some improvement for isolated and semi-dense contacts. With further optimization of filter, it is expected to have better results with matched lithography set with filter.

Date Published: 5 July 2000
PDF: 6 pages
Proc. SPIE 4000, Optical Microlithography XIII, (5 July 2000); doi: 10.1117/12.388944

Published in SPIE Proceedings Vol. 4000:
Optical Microlithography XIII
Christopher J. Progler, Editor(s)