Paper
17 December 2003 Using location of diffraction orders to predict performance of future scanners
Peter Brooker
Author Affiliations +
Abstract
Predictions have been made from exposure tool manufacturers as to the dense line lithographic capabilities of present and future tools. In particular, the predictions specify which dense line pitch will be achievable as a function of wavelength, mask type, NA and illumination conditions. Tremendous insight can be gained into these predictions by investigating the location of the first diffraction order with respect to the edge of the objective aperture for each case. Simple rules for dense line/spaces will be developed regarding scanner capabilities from the perspective of diffraction order location. These rules will then be used to predict line/space capabilities for hyper-NA systems. For reference, the diffraction order patterns of dense contacts and a representative DRAM brick wall structure will be presented. Also included in the paper will be a detailed derivation of the diffraction equations for dense lines and spaces for 180 degree alternating aperture phase shift masks. This derivation shows explicitly how the n=0 order is suppressed. It is the extension of previous work that derived the diffraction equations for a non phase shifted array of slits.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter Brooker "Using location of diffraction orders to predict performance of future scanners", Proc. SPIE 5256, 23rd Annual BACUS Symposium on Photomask Technology, (17 December 2003); https://doi.org/10.1117/12.518040
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KEYWORDS
Diffraction

Lithography

Phase shifts

Photomasks

Objectives

Manufacturing

Scanners

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