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Proceedings Paper

Wafer steppers for the 64-M and 256-Mbit memory generations
Author(s): William H. Arnold; Gary C. Escher
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Paper Abstract

Optical wafer steppers are used in the fabrication of submicron and subhalf micron integrated circuits. The SIA Technology Roadmap has outlined the major requirements steppers must meet for the 64M and 256Mbit memory generations. These include 0.35 μm and 0.25 μm resolution over 22 and 27 mm square image fields. This article outlines these requirements and explores the impact on wafer stepper design and use. Stepper cost of ownership will be considered including the contribution of the reticle to the overall cost of the process.

Two major trends can be discerned. First, the requirement of 0.25 μm imaging over fields larger than a square inch forces the adoption of step and scan technologies as the cost and size of full field lenses grow noncompetitive. Second, in order to reduce the overall cost of ownership of the photolithography process, the industry is adopting mix-and-match strategies using high NA steppers to print critical mask layers and high speed, low NA, wide field steppers to print non-critical layers.

Paper Details

Date Published: 1 January 1994
PDF: 40 pages
Proc. SPIE 10273, 64-to 256-Megabit Reticle Generation: Technology Requirements and Approaches: A Critical Review, 1027305 (1 January 1994); doi: 10.1117/12.177438
Show Author Affiliations
William H. Arnold, Advanced Micro Devices, Inc. (United States)
Gary C. Escher, SEMATECH (United States)

Published in SPIE Proceedings Vol. 10273:
64-to 256-Megabit Reticle Generation: Technology Requirements and Approaches: A Critical Review
Gregory K. Hearn, Editor(s)

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