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Method for Synthesis of Alkali Soluble Silsesquioxane Polymers

IP.com Disclosure Number: IPCOM000121724D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 25K

Publishing Venue

IBM

Related People

Hefferon, GJ: AUTHOR [+4]

Abstract

Alkali soluble silsesquioxane polymers satisfy the requirements of a base polymer in a silicon bilayer photoresist system. One such polymer, poly(hydroxybenzylsilsesquioxane), is the subject of U.S. Patent 4,745,169. The method of synthesis of this polymer described in the patent involves the conversion of the methoxy groups on poly(methoxybenzylsilsesquioxane) to hydroxy groups. This conversion was carried out with a trimethylsilyl iodide reagent under vigorous conditions. We have found this reaction to be very irreproducible, often giving crosslinked polymer. An improved method of demethylation of methoxybenzyl- or methoxyphenylsilsesquioxane-type polymers (or copolymers) is to treat with boron tribromide reagent under mild conditions.

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Method for Synthesis of Alkali Soluble Silsesquioxane Polymers

      Alkali soluble silsesquioxane polymers satisfy the
requirements of a base polymer in a silicon bilayer photoresist
system.  One such polymer, poly(hydroxybenzylsilsesquioxane), is the
subject of U.S. Patent 4,745,169.  The method of synthesis of this
polymer described in the patent involves the conversion of the
methoxy groups on poly(methoxybenzylsilsesquioxane) to hydroxy
groups.  This conversion was carried out with a trimethylsilyl iodide
reagent under vigorous conditions.  We have found this reaction to be
very irreproducible, often giving crosslinked polymer.  An improved
method of demethylation of methoxybenzyl- or
methoxyphenylsilsesquioxane-type polymers (or copolymers) is to treat
with boron tribromide reagent under mild conditions.  The amount of
boron tribromide controls the amount of conversion from methoxy to
hydroxy groups in the resulting alkali soluble polymer (or
copolymer).