Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2002-10-11
2004-09-14
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S191000, C430S192000, C430S193000, C430S326000, C525S487000
Reexamination Certificate
active
06790581
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a silicone resin/phenolic resin hybrid compound in which a silicone resin component is dispersed within a phenolic resin at a molecular level and the silicone resin component and phenolic resin are interlocked in a network-like manner. The invention also relates to a resist containing the hybrid compound, and to a patterning process which uses the resist.
2. Prior Art
The use of novolac resin-containing organic-inorganic polymer hybrids as resists and a method for the preparation of such hybrids are described in JP-A 2000-44876 and JP-A 2000-56453. Resists of this type purportedly enhance the heat resistance of the resist film, making it less subject to deformation, and also improve the dry etching resistance of the film.
In semiconductor integrated circuit applications, the substrate to which the resist is applied generally is a silicon wafer. Lately, however, a variety of applications are being proposed which call for the use of resists on not only silicon substrates, but also metal substrates such as copper, gold, aluminum, chromium, titanium and tantalum substrates. The resist film must have the ability to adhere to such metal substrates.
Methods for improving adhesion of the resist to the substrate include, in particular, the incorporation of an additive, such as that obtained by adding an organic hydroperoxide to an N-substituted imide (JP-B 48-3616), the addition of an aminoalkoxysilane (JP-A 51-52002), the addition of a chelate complex-forming hydroxyl group-bearing aromatic or aliphatic compound (JP-A 52-54503), and the addition of a silane coupling agent (JP-A 53-39115). However, the use of any of these compounds as an additive includes among its drawbacks the risk of inducing microphase separation, depending on the compatibility of the additive with the other resist components.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a hybrid compound which is highly suitable for use as the base polymer in a resist and which imparts the resist with good adhesion to substrates, especially metal substrates. Another object of the invention is to provide a resist containing such a hybrid compound. A further object of the invention is to provide a patterning process that makes use of such a resist.
We have found that the use of a silicone resin/phenolic resin hybrid compound wherein a silicone resin component is dispersed within a phenolic resin at the molecular level and the phenolic resin and silicone resin component are interlocked in a network-like manner enables the dispersed silicone resin component to form complexes with various metals and their oxide film molecules, thereby enhancing adhesion.
Accordingly, the invention provides a hybrid compound which includes a phenolic resin and a silicone resin prepared by the hydrolysis and condensation of an organooxysilane of the general formula (1):
R
1
n
Si(OR
2
)
4-n
(1)
wherein R
1
is a sulfur- or oxygen-bearing monovalent hydrocarbon group, R
2
represents a monovalent hydrocarbon group, and n is 1 or 2.
In the hybrid compound, the phenolic resin is preferably a novolac resin comprising recurring units of the general formula (2):
wherein m is an integer from 0 to 3, which has a polystyrene equivalent weight-average molecular weight of 1,000 to 10,000, and in which 1 to 50 mol % of the hydroxyl group hydrogens are substituted with 1,2-naphthoquinonediazido-sulfonyl ester groups.
The invention also provides a resist comprising the foregoing hybrid compound.
The invention further provides a patterning process which includes the steps of (i) applying the foregoing resist to a substrate, (ii) exposing the applied resist through a photomask to light having a wavelength of 150 to 450 nm, and (iii) developing the exposed resist with a liquid developer.
DETAILED DESCRIPTION OF THE INVENTION
The silicone resin/phenolic resin hybrid compound of the invention is a compound obtained by adding an organooxysilane of the general formula (1):
R
1
n
Si(OR
2
)
4-n
(1)
to a phenolic resin, then subjecting the organooxysilane to a sol-gel reaction via hydrolysis and condensation. In the compound, the silicone resin derived from the organooxysilane is interlocked with the phenolic resin in a network-like manner.
In above general formula (1), R
1
is a sulfur- or oxygen-bearing monovalent hydrocarbon group, R
2
represents a monovalent hydrocarbon group, and the letter n is 1 or 2. Illustrative examples of sulfur-bearing monovalent hydrocarbon groups that may serve as R
1
include mercapto group-containing C
1-8
alkyls such as mercaptomethyl, mercaptoethyl, mercaptopropyl, mercaptobutyl, mercaptopentyl, mercaptohexyl, mercaptobutyl and mercaptooctyl; mercapto group-containing C
6-10
aryls such as mercaptophenyl and mercaptomethylphenyl; and mercapto group-containing C
7-12
aralkyls such as mercaptobenzyl, mercaptomethylbenzyl and 2-phenyl-1-mercaptoethyl.
Illustrative examples of oxygen-bearing monovalent hydrocarbon groups that may serve as R
1
include glycidoxy or epoxy group-containing C
4-8
alkyls such as glycidoxymethyl, glycidoxyethyl, glycidoxypropyl, glycidoxybutyl, glycidoxypentyl and (3,4-epoxycyclohexyl)ethyl; and methacryloxy group-containing C
4-8
alkyls such as methacryloxymethyl, methacryloxyethyl, methacryloxypropyl and methacryloxybutyl.
Illustrative examples of the monovalent hydrocarbon groups represented in the above formula as R
2
include C
1-8
alkyls, C
6-10
aryls such as phenyl and tolyl, and C
7-12
aralkyls such as benzyl and phenylethyl.
Phenolic resins that may be used in the invention include substituted or unsubstituted novolac resins and polyhydroxystyrene resins. Preferable use can be made of a novolac resin which has recurring units of the general formula (2):
wherein m is an integer from 0 to 3, which has a polystyrene equivalent weight-average molecular weight of 1,000 to 10,000, and in which 1 to 50 mol %, especially 3 to 30 mol % of the hydroxyl group hydrogens are substituted with 1,2-naphthoquinonediazidosulfonyl ester groups.
If the novolac resin includes photosensitive groups as substituents, the photosensitive groups are preferably, though not necessarily, naphthoquinonediazide groups.
The silicone resin/phenolic resin hybrid compound of the invention can be prepared by the following method.
A phenolic resin is dissolved in an alcohol having 1 to 8 carbons, such as methanol or ethanol. An organooxysilane component of above general formula (1) is added to the resulting solution, and a sol-gel reaction is carried out via hydrolysis and condensation in the presence of water. An acid such as hydrochloric acid or p-toluenesulfonic acid may be added as the catalyst, although acid addition is not always necessary because the hydroxyl groups on the phenolic resin are intrinsically acidic. The organooxysilane of above formula (1) is used in an amount of preferably 1 to 60 wt %, and most preferably 3 to 50 wt %, based on the phenolic resin. At less than 1 wt % of the organooxysilane, it may be impossible to achieve the object of the invention. On the other hand, an organooxysilane content of more than 60 wt % may greatly compromise the uniformity of application and the resolution of the resist.
The sol-gel reaction may be carried out by an ordinary method for the hydrolysis and condensation of organooxysilane, although reaction at a temperature of 20 to 80° C., and especially 30 to 60° C., for a period of 0.5 to 5 hours, and especially 1 to 3 hours, is preferred.
Following the reaction, the product can be used as a resist component once the alcohol that has formed in the reaction and excess water have been removed by distillation. Such removal of alcohol and water is preferably carried out by vacuum distillation at a temperature of less than 40° C. If the organooxysilane contains photosensitive substituents such as naphthoquinonediazide groups, raising the temperature too high may lead to decomposition of the naphthoquinonediazide groups, resulting in a loss
Furihata Tomoyoshi
Kato Hideto
Birch & Stewart Kolasch & Birch, LLP
Chu John S.
Shin-Etsu Chemical Company Limited
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