Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

A new spatial filtering technique is proposed for improving image contrast and depth of focus in projection photolithography. The technique is based on fractional Fourier domain filtering. Unlike the current pupil filtering method, the fractional filter can be placed at any location along the projection optical path other than the pupil plane. The theory of partial coherent diffraction combined with fractional Fourier domain filtering is presented. Phase filters for contact hole and line-space patterns have been designed. Computer simulation of complete imaging process including fractional Fourier domain filtering have been carried out. The simulation has demonstrated that the new filtering technique can significantly improve image fidelity, reduce the optical proximity effect and increase the depth of focus. Because of the flexibility in filter location, it is predicted to be easier to implement in a practical optical lithography system. © 2003 Elsevier Science B.V. All rights reserved.

Original publication

DOI

10.1016/S0167-9317(03)00056-X

Type

Conference paper

Publication Date

01/06/2003

Volume

67-68

Pages

31 - 38