Browse Prior Art Database

Lithography At 157 NM

IP.com Disclosure Number: IPCOM000044734D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Jain, K: AUTHOR [+3]

Abstract

The following is the shortest-wavelength optical lithography to date. The optical source, instead of conventional Hg lamps and ultraviolet lasers, is a vacuum-UV fluorine laser operating at 157 nm. This is a molecular fluorine laser excited by an electric discharge in a mixture of He and F2 or He, F2 and Ne. We exposed a number of photoresist materials at this wavelength and were able to develop them in different developers. Among the materials exposed are PMMA (Polymethylmethacrylate), PMIPK, AZ1350J and an experimental diazonaphthoquinone-novolak resist. The exposed PMMA developed in the conventional MIBK+ water solution, PMIPK in acetone as well as ODUR 1010, and AZ1350J in the commercial AZ351 developer.

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Lithography At 157 NM

The following is the shortest-wavelength optical lithography to date. The optical source, instead of conventional Hg lamps and ultraviolet lasers, is a vacuum-UV fluorine laser operating at 157 nm. This is a molecular fluorine laser excited by an electric discharge in a mixture of He and F2 or He, F2 and Ne. We exposed a number of photoresist materials at this wavelength and were able to develop them in different developers. Among the materials exposed are PMMA (Polymethylmethacrylate), PMIPK, AZ1350J and an experimental diazonaphthoquinone-novolak resist. The exposed PMMA developed in the conventional MIBK+ water solution, PMIPK in acetone as well as ODUR 1010, and AZ1350J in the commercial AZ351 developer.

Optics for 157 nm Suprasil quartz does not transmit at 157 nm. Hence, one must go to other optical materials. Suitable materials for use at this wavelength are CaF2, MgF2, etc. A mask made on CaF2 or MgF2 as the substrate will work for both contact and projection lithography. For lenses, these and other alkali halides will be suitable. For reflective optics, aluminum mirrors will work.

Anonymous

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