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Proximity Correction Technique for Electron-Beam Tools

IP.com Disclosure Number: IPCOM000042423D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Guillaume, WJ: AUTHOR [+2]

Abstract

In electron-beam wafer and mask writing applications, it is well known that proximity correction algorithms are required to vary electron-beam dose levels to compensate for intra proximity effects and tool focus deviations [*]. Disclosed herein is a technique for determining which shapes are to be presented to the proximity correction algorithm for dose assignment. The technique provides smoother dose transition, consistent dose assignment, and dramatically reduces proximity correction algorithm processing time. The technique operates on electron-beam mask writing shape data as follows: 1. The outside edges of the shapes are separated from the interior, reflecting the observation that dose assignment to the edges is far more critical than dose assignment to the interior. 2.

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Proximity Correction Technique for Electron-Beam Tools

In electron-beam wafer and mask writing applications, it is well known that proximity correction algorithms are required to vary electron-beam dose levels to compensate for intra proximity effects and tool focus deviations [*]. Disclosed herein is a technique for determining which shapes are to be presented to the proximity correction algorithm for dose assignment. The technique provides smoother dose transition, consistent dose assignment, and dramatically reduces proximity correction algorithm processing time. The technique operates on electron-beam mask writing shape data as follows: 1. The outside edges of the shapes are separated from the interior, reflecting the observation that dose assignment to the edges is far more critical than dose assignment to the interior.
2. The interior shapes are assigned an empirically determined dose and are not corrected any further, dramatically reducing proximity correction algorithm processing time. 3. The edges are divided into coarse segments of 40-50 micrometers to minimize the number of neighboring shapes and reduce the overall execution time. 4. The neighborhood of shapes in the immediate vicinity of each coarse segment is built by including all shapes within a predefined radius around the coarse segment. This occurs in an algorithmically reproducible manner, thus assuring that similar shapes will have similar neighborhoods and be assigned similar doses. 5. All of...