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Proceedings Paper

Hierarchical proximity correction using CAPROX
Author(s): Ulrich Hofmann; Christian K. Kalus; Anja Rosenbusch; Hiroyuki Endo; Yasuki Kimura; Akihiro Endo
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Paper Abstract

The proximity effect in e-beam lithography is well known and many solutions exist to correct it. But none of them are able to cope with the amount of data in today's large scale memories. In a conventional approach, the 64 Mb DRAM would lead to 10 Gigabytes of flat data and weeks of processing time, for example. Recently, Sigma-C achieved a breakthrough in handling USLIs by developing a generic algorithm for many different hierarchical processes. It solves throughput problems for operations like overlap removal (OLR); the e-beam (EPC) and optical proximity correction (OPC) which, at first glance, are inaccessible to hierarchical processing. Hierarchical algorithms take advantage of the growing symmetry of a layout with the number of designed shapes. Even after all processing steps a ULSI device will have hierarchy, not necessarily the same as on input, but yet enough to significantly decrease processing times. Hierarchical processing is a general outline which can be used for many different applications. Most parts of this algorithmic scheme are identical, only one part must be adapted for each application. This paper shows the general outline of hierarchical processing and the solution of the algorithmic steps specific to the hierarchical e-beam proximity correction. Subsequently, the application on a variety of critical layers of the 64 and 256 Mb DRAM is demonstrated using a workstation. Corrected and uncorrected exposures are compared by SEM pictures and line width measurements. The correction not only opens the process window, it turns out to be an enabling technique for critical layers.

Paper Details

Date Published: 8 December 1995
PDF: 10 pages
Proc. SPIE 2621, 15th Annual BACUS Symposium on Photomask Technology and Management, (8 December 1995); doi: 10.1117/12.228210
Show Author Affiliations
Ulrich Hofmann, Sigma-C GmbH (Germany)
Christian K. Kalus, Sigma-C GmbH (Germany)
Anja Rosenbusch, Sigma-C GmbH (Germany)
Hiroyuki Endo, OKI Electric Ltd. (Japan)
Yasuki Kimura, OKI Electric Ltd. (Japan)
Akihiro Endo, OKI Electric Ltd. (Japan)

Published in SPIE Proceedings Vol. 2621:
15th Annual BACUS Symposium on Photomask Technology and Management
Gilbert V. Shelden; James N. Wiley, Editor(s)

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