Methods and apparatus for lithography of sparse arrays of sub-micrometer features

US5759744A · kind A · utility

Assignee

• The Regents of the University of New Mexico · US

Inventors

• Steven R. J. Brueck · Albuquerque, US
• Xiaolan Chen · Beaverton, US
• Saleem Zaidi · Albuquerque, US
• Daniel J. Devine · Seattle, US

Key dates

• Filing date: Mar 16, 1995
• Grant date: Jun 2, 1998
• Expiry date: Mar 16, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70466
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Methods and apparatuses are disclosed for the exposure of sparse hole and/or mesa arrays with line:space ratios of 1:3 or greater and sub-micrometer hole and/or mesa diameters in a layer of photosensitive material atop a layered material. Methods disclosed include: double exposure interferometric lithography pairs in which only those areas near the overlapping maxima of each single-period exposure pair receive a clearing exposure dose; double interferometric lithography exposure pairs with additional processing steps to transfer the array from a first single-period interferometric lithography exposure pair into an intermediate mask layer and a second single-period interferometric lithography exposure to further select a subset of the first array of holes; a double exposure of a single period interferometric lithography exposure pair to define a dense array of sub-micrometer holes and an optical lithography exposure in which only those holes near maxima of both exposures receive a clearing exposure dose; combination of a single-period interferometric exposure pair, processing to transfer resulting dense array of sub-micrometer holes into an intermediate etch mask, and an optical lit…