Browse Prior Art Database

Silsesquioxane/Acid Photogenerator Resist

IP.com Disclosure Number: IPCOM000101250D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 101K

Publishing Venue

IBM

Related People

Brunsvold, W: AUTHOR [+4]

Abstract

Resist compositions containing tetraphenylcyclotetrasiloxanetetrol (TCS) and polyphenylsilsesquioxanes (PSQ) in the presence of acid photogenerators are effective negative tone resist systems. We find that the incorporation of these materials into a suitable phenolic polymer matrix provides a highly sensitive, oxygen reactive ion etch (RIE) resistant imaging layer which can be utilized in either single layer or multilayer resist schemes. Suitable phenolic resins may be either novolac or poly (4-hydroxystyrene) (PHS) or derivatives of PHS. Acid photogenerators can be onium salts such as triarylsulfonium salts or diaryliodonium salts, o-nitrobenzylsulfonates, N-imidosulfonates or triflates, or suitable triazene derivatives.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Silsesquioxane/Acid Photogenerator Resist

       Resist compositions containing
tetraphenylcyclotetrasiloxanetetrol (TCS) and
polyphenylsilsesquioxanes (PSQ) in the presence of acid
photogenerators are effective negative tone resist systems. We find
that the incorporation of these materials into a suitable phenolic
polymer matrix provides a highly sensitive, oxygen reactive ion etch
(RIE) resistant imaging layer which can be utilized in either single
layer or multilayer resist schemes.  Suitable phenolic resins may be
either novolac or poly (4-hydroxystyrene) (PHS) or derivatives of
PHS.  Acid photogenerators can be onium salts such as
triarylsulfonium salts or diaryliodonium salts,
o-nitrobenzylsulfonates, N-imidosulfonates or triflates, or suitable
triazene derivatives.  The resists prepared in this fashion are quite
sensitive to electron beams, X-rays, and optical (photon) light
beams.

      The ratio of silsesquioxanes in the resist formulation can be
utilized to provide both high etch resistance and suitable
development characteristics.  The overall ratio of silsesquioxanes to
total solids content is important in obtaining high oxygen RIE
resistance.  Typical useful resist compositions should contain about
40-50% silsesquioxanes. For example, a resist containing 100 parts
novolac, 60 parts PSQ, 20 parts TCS, and 5 parts triphenylsulfonium
hexafluoroantimonate is totally etch resistant for 20 minutes in a 10
mtorr oxygen plasma despite the fact that the silicon weight
percentage for this composition is only about 9%.  The ratio of PSQ
to TCS is utilized to tailor the resist for a given developer.  TCS
accelerates development rate, whereas PSQ retards it.  This provides
a wide latitude for different developer strengths.  Metal-ion free
developers are appropriate for formulations which contain large
percentages of TCS.

      Silsesquioxane/acid photogenerator resist is quite sensitive to
deep-uv radiation requiring only a 5-10 mJ/cm(2) dose.  Improved
deep- uv resists for application as single layer resists can be
obtained by using PHS or PHS derivatives as the matrix resin due to
the improved optical characteristics of these materials in the
deep-uv.  The dose requirement in this case drops to 2-5 mJ/cm(2),
and the contrast is greater than 4.  Image resolution down to 0.75
micron have been obtained on a Perkin Elmer 500 Scanning Projection
Exposure Tool in the UV-2 mode.

      The resist shows a unique bimodal characteristic. Resist films
exposed to ver...