Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
1997-12-22
2001-06-19
Geist, Gary (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S117000, C560S210000, C560S238000
Reexamination Certificate
active
06248920
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of esters, more particularly, a process for the preparation of esters having a large steric hindrance. According to the present invention, the target esters can be easily and effectively prepared. The present invention also relates to a process for the preparation of a chemically amplified resist material comprising an alicyclic hydrocarbon group-containing polymer, which comprises polymerizing esters after they were prepared in accordance with the preparation process of the present invention. As will be appreciated from the descriptions of this specification, the term “polymer” used herein is intended to mean both a homopolymer and a copolymer which is produced by the simultaneous polymerization of two, three or more dissimilar monomeric compounds or monomers. The chemically amplified resist material can exhibit a high resolution, a high sensitivity and an excellent resistance to dry etching. The resist composition of the present invention can exhibit a high sensitivity and stable patterning properties which are particularly desired in the field of KrF and ArF lithography. In addition, the present invention relates to a process for the production of a semiconductor devices such as semiconductor integrated circuits, for example, LSIs, VLSIs, ULSIs and other devices, using the chemically amplified resist material of the present invention in a lithographic process.
2. Description of the Related Art
Recently, in the field of the production of semiconductor devices, to satisfy the requirements for the formation of fine resist patterns, attention has been made to a chemically amplified resist material and lithographic process using such material. At present, a wide variety of chemically amplified resist materials are well known.
For example, as is disclosed in Japanese Unexamined Patent Publication (Kokai) No. 4-39665, the inventor of the present application has invented a chemically amplified resist material characterized by comprising a polymer or copolymer of acrylic acid ester or a-substituted acrylic acid ester in which the ester portion contains an adamantane skeleton. The chemically amplified resist material can be effectively used in the formation of submicron-ordered resist patterns using as a patterning radiation the radiation in the range of far ultraviolet or vacuum ultraviolet lights, because they have an excellent transparency to the patterning radiation and also a high resistance to dry etching.
The resist polymers or copolymers containing the above-described ester structure are generally produced by reacting an alcohol containing the part corresponding to said ester structure with an acid or acid halide, that is, using conventional esterification methods, to produce an ester, followed by conducting a polymerization reaction using the ester as a starting monomer. However, the production process has a drawback in that, using the conventional methods, it is difficult to easily, effectively and stably carry out the preparation of the ester. For example, the previous preparation of an alcohol as the starting material is troublesome. Further, if the esterification of a tertiary alcohol is carried out to obtain a target ester, a dissociation reaction may be caused in the resulting ester due to the presence of stable carbocations, and an esterification reaction itself is inhibited due to the steric hindrance of the contained substituents.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a process for the easy and stable preparation of esters, having large steric hindrance, with a high yield.
Another object of the present invention is to provide a process for the easy preparation of a resist material having excellent performances by using the simplified steps.
Still another object of the present invention is to provide a process for the production of a semiconductor device using the above-described resist material of the present invention.
Other objects of the present invention will be appreciated from the below-mentioned detailed description of the present invention.
In one aspect thereof, the present invention provides a process, for the preparation of esters, which comprises reacting an aldehyde or ketone compound and an acid halide compound in a one pot reaction in the presence of at least one compound represented by the following formulae (I), (II) and (III):
RMgX (I);
RMgX/CuX (II); and
RLi or R(CuLi)
½
(III);
in which
R represents a hydrocarbon group, and
X represents a halogen atom.
According to the preparation process of the present invention, since the aldehyde or ketone compound and the acid halide compound are used as the starting material for the esterification reaction, and also the esterification reaction is carried out in the presence of the specific Gringnard compound and/or an organic lithium compound, the esterification reaction can proceed quantitatively, thus ensuring a high yield as a result of easy purification of the products. Further, since there is no necessity to previously synthesize the corresponding alcohol as in the conventional methods, the reaction steps can be included in a so-called “one pot reaction”, thereby ensuring a simplified production process. Further, in addition to the simplification of the production process, it becomes possible to prepare a wide variety of ester compounds by suitably selecting the aldehyde or ketone compound and the Gringnard compound and/or the organic lithium compound. In particular, it has been found that the preparation process of the present invention can be very effectively carried out if the aldehyde or ketone compound used contains an alicyclic hydrocarbon group such as adamantyl, norbornyl, cyclohexyl, terpene and the like, or a bulky alkyl group such as isopropyl, sec-butyl, iso-amyl and the like.
In another aspect thereof, the present invention provides a process for the preparation of a resist material which comprises an alkali-insoluble, acid-sensitive polymer having a repeating unit containing a protected alkali-soluble group in which unit an alkali-soluble group is cleaved with an acid to thereby render said polymer alkali-soluble, said process comprising the steps of:
reacting an aldehyde or ketone compound and an acid halide compound, each of which has a structure necessary to complete a part of the repeating unit of said polymer, in a one pot reaction in the presence of at least one compound represented by the above-described formulae (I), (II) and (III);
polymerizing the resulting esters by themselves or with other monomeric compound in the presence of a polymerization initiator; and
mixing the thus obtained acid-sensitive polymer with a photoacid generator capable of producing an acid upon exposure to a patterning radiation.
Using the preparation process of the present invention, it becomes possible to prepare the resist material in a simplified method and, with regard to the thus obtained resist material, it becomes possible to obtain a high resolution, a high sensitivity and an excellent resistance to etching because of the structure and function of the acid-sensitive polymer constituting the resist material.
In a still another aspect thereof, the present invention provides a process for the production of a semiconductor device, which comprises the steps of:
reacting an aldehyde or ketone compound and an acid halide compound in a one pot reaction in the presence of at least one compound represented by the above-described formulae (I), (II) and (III);
polymerizing the resulting esters by themselves or with other monomeric compound in the presence of a polymerization initiator;
mixing the resulting acid-sensitive polymer with a photoacid generator capable of producing an acid upon exposure to a patterning radiation to obtain a resist material;
coating the resist material on a surface of a semiconductor substrate; and
subjecting a layer of said resist material to exposure, PEB (post exposure ba
Kikukawa Tadashi
Takechi Satoshi
Armstrong Westerman Hattori McLeland & Naughton LLP
Fujitsu Limited
Geist Gary
Oh Taylor V.
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