Tertiary alcohol compounds having an alicyclic structure

Details Tertiary alcohol compounds having an alicyclic structure Tertiary alcohol compounds having an alicyclic structure

2001-12-19

2002-10-22

Shippen, Michael L. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

C568S817000

Reexamination Certificate

active

06469220

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to Japanese Patent Application No. 2000-391867, filed Dec. 25, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to novel tertiary alcohol compounds which are useful as monomers for the preparation of base resins for chemical amplification resist materials suitable for use in fine processing techniques.
2. Description of the Related Art
In recent years, increasingly finer pattern rules are required as the degree of integration and speed of LSIs become higher. Under these circumstances, far ultraviolet lithography is regarded as a promising fine processing technique of the next generation. In particular, photolithography using KrF or ArF excimer laser light as the light source is considered to be a technique indispensable for ultrafine processing to a size of 0.3 &mgr;m or less, and its realization is eagerly desired.
With regard to resist materials for use in photolithography using excimer laser tight (in particular, ArF excimer laser light having a wavelength of 193 nm) as the light source, it is required that they not only have high transparency at the relevant wavelength, but also have high etching resistance which allows a reduction in film thickness, high sensitivity which does not overload the expensive materials of the optical system, and among others, high resolving power which permits fine patterns to be accurately formed. In order to meet these requirements, it is essential to develop a base resin having high transparency, high rigidity and high reactivity. However, no polymer having all of these characteristics is known at present. Thus, the existing state of the art is that no resist material suitable for practical use is available as yet.
As highly transparent resins, copolymers of acrylic acid or methacrylic acid derivatives, polymers containing an alicyclic compound derived from a norbornene derivative in the main chain, and the like are known, but none of them are satisfactory. For example, it is relatively easy to enhance the reactivity of copolymers of acrylic acid or methacrylic acid derivatives, because highly reactive monomers may be freely introduced thereinto or acid-labile units may be arbitrarily increased. However, the structure of the main chain makes it very difficult to enhance its rigidity. On the other hand, the rigidity of polymers containing an alicyclic compound in the main chain is within acceptable limits. However, their reactivity cannot be easily enhanced because, owing to the structure of the main chain, their reactivity with acid is lower than that of poly(meth)acrylates and their latitude in polymerization is low. In addition, they also have the disadvantage that, when they are applied to a substrate, their adhesion is poor because of the high hydrophobicity of the main chain. Consequently, when resist materials are prepared by using these polymers as base resins, the result will be such that they have sufficient sensitivity or resolving power, but cannot withstand etching, or they have acceptable etching resistance, but their sensitivity and resolving power are too low for practical purposes. As used herein, the term “(meth)acrylate” means a methacrylate or an acrylate.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide novel tertiary alcohol compounds which are useful as monomers for the preparation of photoresist materials having high transparency and a great affinity for the substrate and hence suitable for use in photolithography using a light source comprising preferably light having a wavelength of 300 nm or less and more preferably light emitted from an ArF excimer laser.
The present inventors carried out intensive investigations with a view to accomplishing the above object, and have now found that tertiary alcohol compounds represented by the following general formula (1) can be obtained in high yield and with simplicity by employing any of the processes which will be described later, and that resins prepared by using these tertiary alcohol compounds have high transparency at the exposure wavelength of an excimer laser and resist materials using them as base resins exhibit high resolving power and good adhesion to the substrate.
wherein R
1
and R
2
each independently represent a straight-chain, branched or cyclic alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms on the constituent carbon atoms may be replaced by a halogen atom or halogen atoms, or R
1
and R
2
may be joined together to form an aliphatic hydrocarbon ring; Z represents a straight-chain, branched or cyclic divalent organic group having 2 to 10 carbon atoms; and k is 0 or 1.
Resist materials prepared by using polymers obtained by polymerization of the tertiary alcohol compounds of the present invention are sensitive to high-energy radiation, having good adhesion to the substrate, high sensitivity, high resolving power and high etching resistance, and are useful for fine processing with electron rays or far ultraviolet radiation. In particular, since they exhibit low absorption at the exposure wavelengths of ArF and KrF excimer lasers, they can easily form fine patterns perpendicular to the substrate and are hence suitable for use as fine pattern forming materials for the manufacture of VLSI (very large scale integration).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be more specifically described hereinbelow.
The tertiary alcohol compounds of the present invention are represented by the general formula (1).
R
1
and R
2
each independently represent a straight-chain, branched or cyclic alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms on the constituent carbon atoms may be replaced by a halogen atom or halogen atoms. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl, cyclohexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, bicyclo[3.3.1]nonyl, bicyclo[4.4.0]decanyl, adamantyl, trifluoromethyl, 2,2,2-trifluoroethyl, 2,2,2-trichloroethyl, 3,3,3-trifluoropropyl and 3,3,3-trichloropropyl. Alternatively, R
1
and R
2
may be joined together to form an aliphatic hydrocarbon ring. Specific examples of the ring so formed include cyclobutane, cyclopentane, cyclohexane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bicyclo[3.3.1]nonane, bicyclo[4.4.0]decane and adamantane. Z represents a straight-chain, branched or cyclic divalent organic group having 2 to 10 carbon atoms. Specific examples thereof include ethylene, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane-1,1-diyl, pentane-1,2-diyl, pentane-1,3-diyl, pentane-1,4-diyl, pentane-1,5-diyl, hexane-1,1-diyl, hexane-1,2-diyl, hexane-1,3-diyl, hexane-1,4-diyl, hexane-1,5-diyl, hexane-1,6-diyl, cyclopropane-1,1-diyl, cyclopropane-1,2-diyl, cyclobutane-1,1-diyl, cyclobutane-1,2-diyl, cyclobutane-1,3-diyl, cyclopentane-1,1-diyl, cyclopentane-1,2-diyl, cyclopentane-1,3-diyl, cyclohexane-1,1-diyl, cyclohexane-1,2-diyl, cyclohexane-1,3-diyl and cyclohexane-1,4-diyl. k is 0 or 1.
Among the tertiary alcohol compounds represented by the general formula (1), tertiary alcohol compounds represented by the following general formula (2) are especially preferred.
wherein R
3
and R
4
each independently represents a straight-chain, branched or cyclic alkyl group having 1 to 6 carbon atoms, or R
3
and R
4
may be joined together to form an aliphatic hydrocarbon ring; and m is an integer satisfying the conditions defined by 3≦m≦6.
In this formula, R
3
and R
4
each independently represent a straight-chain, branched or cyclic alkyl group having 1 to 6 carbon atoms. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pe

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