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A New Deep Ultraviolet Negative Acting Photoresist, EPNR

IP.com Disclosure Number: IPCOM000119783D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Collini, GJ: AUTHOR [+4]

Abstract

A negative photoresist has been formulated from a mixture of epoxy novolak polymer, (EPN); parahydroxystyrene, (PHS), polymer; and a radiation sensitive triaryluslfonium hexafluoroantimate salt. The polymers are used in weight ratios, EPN/PHS, in the range 99:1 to 80:20, and with salt to polymer weight ratios of 0.25 to 10%. The above solid components are dissolved in a casting solvent typically three times their total weight such as propylene glycol monomethyl ether acetate to form the photoresist solution. This solution is then spun coated on a wafer in the usual fashion and soft baked at 95 +/- 5oC for 30 minutes to afford a smooth resist coating.

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A New Deep Ultraviolet Negative Acting Photoresist, EPNR

      A negative photoresist has been formulated from a mixture of
epoxy novolak polymer, (EPN); parahydroxystyrene, (PHS), polymer; and
a radiation sensitive triaryluslfonium hexafluoroantimate salt.  The
polymers are used in weight ratios, EPN/PHS, in the range 99:1 to
80:20, and with salt to polymer weight ratios of 0.25 to 10%.  The
above solid components are dissolved in a casting solvent typically
three times their total weight such as propylene glycol monomethyl
ether acetate to form the photoresist solution. This solution is then
spun coated on a wafer in the usual fashion and soft baked at 95
5oC for 30 minutes to afford a smooth resist coating.  Upon exposure
to patterned radiation, such as a deep ultraviolet Perkin Elmer
Microaligner with 2 to 20 mJ/cm2, a chemical reaction occurs with the
onium salt which produces a strong acid.  A subsequent additional
bake at 95oC for 75 seconds causes the strong acid to crosslink the
EPN in the patterned areas. Subsequent dip or spray development in
developers, such as methyl isobutyl ketone, affords a sharply defined
submicron patterned stencil on the wafer, which can be used for
applications, such as an ion implant mask, or a wet or reactive ion
etch.  The PHS serves as a modifier of the high photospeed of the EPN
and thereby allows convenient exposure doses and good control of
image sizes.

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