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Proceedings Paper

Optical lithography--thirty years and three orders of magnitude: the evolution of optical lithography tools
Author(s): John H. Bruning
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Paper Abstract

The evolution of optical lithography is traced back more than 30 years to its beginnings with contact printing. As the complexity of integrated circuits increased, the intolerance for defects drove the industry to projection printing. Projection printing was introduced in the early 1970s by imaging the full wafer at 1:1 magnification. The rapid increase in wafer sizes was accommodated by annular field scanning using 1:1 imaging mirror systems. Decreased linewidths and tighter overlay budgets combined with larger wafers created huge difficulties for the mask maker which weren't relieved until the introduction of reduction step-and- repeat printing of small blocks of chips in the late 1970s. Further demands for smaller linewidths and larger chips have driven optical lithography to shorter wavelengths and to scanning the chip in a step-and-scan printing mode. Future advancements in lithography will likely combine novel scanning techniques with further reductions in wavelength.

Paper Details

Date Published: 7 July 1997
PDF: 14 pages
Proc. SPIE 3048, Emerging Lithographic Technologies, (7 July 1997); doi: 10.1117/12.275782
Show Author Affiliations
John H. Bruning, Tropel Corp. (United States)

Published in SPIE Proceedings Vol. 3048:
Emerging Lithographic Technologies
David E. Seeger, Editor(s)

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