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Proceedings Paper

Alternating phase-shift generation for complex circuit designs
Author(s): Gerald Galan; Frederic P. Lalanne; Michel Tissier; Marc Belleville
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Paper Abstract

One of the main challenges for the industrialization of the alternating phase shift mask technique is the geometrical design of the phase shifters. The problem is complex and software development is required to achieve automation. This data preparation is necessary in order to apply the most powerful optical enhancement technique, the alternating PSM, to the gate lithography of logic designs. After the implementation of an algorithm, very promising on small flat geometrical designs of a few hundred transistors, it has been decided to test this software on complete circuits. This paper deals with the issues associated with alternating pattern generation on complex circuits. In particular, the use of layout hierarchy is essential to obtain an acceptable amount of manual intervention and computer processing time. There are two kinds of limitations to this global approach. First, the overlapping or the proximity of cells in the hierarchy may not be compatible with a cell-by-cell generation of phase shifters. Secondly, some local design configurations may be difficult to phase shift. The question is: `is the number of occurrences of such cases manageable?' This presentation is illustrated by our experience on a multiplier design of about 15000 transistors, created using a standard cell library in 0.25 micron technology. This work shows that the theoretically difficult cases of layout hierarchy or geometrical design are not critical in practice. In particular, the design method based on standard cell libraries creates a hierarchy which is very favorable to our approach. This article presents a method for the alternating pattern generation on complex circuits which is based on two main points: first, on a software able to generate alternating phase shifters on small flat cells, and secondly, on the advantage of using layout hierarchy.

Paper Details

Date Published: 27 December 1996
PDF: 12 pages
Proc. SPIE 2884, 16th Annual BACUS Symposium on Photomask Technology and Management, (27 December 1996); doi: 10.1117/12.262843
Show Author Affiliations
Gerald Galan, France Telecom (France)
Frederic P. Lalanne, France Telecom (France)
Michel Tissier, Compagnie IBM France (France)
Marc Belleville, LETI-CEA (France)

Published in SPIE Proceedings Vol. 2884:
16th Annual BACUS Symposium on Photomask Technology and Management
Gilbert V. Shelden; James A. Reynolds, Editor(s)

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