Intel is reported to be working on "computational lithography", a form of inverse lithography, to address the challenge of DFM at 22-nm node. Mike Mayberry, director of components research and vice president of technology within Intel's Manufacturing Group and senior fellow Yan Borodovsky, director of advanced lithography in the company's Technology and Manufacturing Group talk about "computational lithography" and its importance at 22-nm node.

For more information, see EETimes Article: Intel tips inverse litho amid EUV delays

by Christopher J. Progler, Photronics, Inc.

For further information on Photronics' advanced reticle manufacturing technologies, see http://www.photronics.com

Abstract
From an optical imaging perspective, photomask design and topography have evolved over the past 10 years from optically thin, light-blocking apertures to optically thick, volumetric scattering elements. The reduction in mask feature size to the sub-wavelength regime coupled with increases in exposure system numerical aperture will continue to push the optics of a photomask toward a more complex and detailed physical model. Moreover, aggressive implementation of resolution enhancement methods in state-of-the-art lithography create mask layouts that resemble diffractive optical elements rather than the electronic circuit patterns the mask is intended to reproduce. In this paper, we address some of the optical characteristics of photomasks for current lithographic technologies, as well as new trends driven by a continued reduction in mask feature size and increased numerical aperture enabled by immersion lithography. As a general conclusion, we find the photomask is best treated and characterized as a true and integrated optical component of the imaging system. By considering the mask from this vantage point, many imaging related issues in advanced lithography may be anticipated and potentially optimized.