Amine compounds, resist compositions and patterning process

Details Amine compounds, resist compositions and patterning process Amine compounds, resist compositions and patterning process

2001-12-06

2004-06-01

Huff, Mark F. (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Imaging affecting physical property of radiation sensitive...

Radiation sensitive composition or product or process of making

C430S325000, C430S326000, C430S330000, C430S327000, C430S328000, C430S296000, C430S905000, C430S914000, C558S452000, C544S106000, C544S098000, C544S056000, C546S184000, C546S330000, C546S246000, C548S215000, C548S566000, C548S579000, C548S950000, C548S954000, C548S967000, C548S969000, C549S347000, C549S352000, C549S353000, C549S494000

Reexamination Certificate

active

06743564

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to novel amine compounds useful as a basic component in resist compositions, novel resist compositions suitable for microfabrication comprising the amine compounds, and a patterning processing using the same.
2. Prior Art
While a number of efforts are currently made to achieve a finer pattern rule in the drive for higher integration and operating speeds in LSI devices, deep-ultraviolet lithography is thought to hold particular promise as the next generation in microfabrication technology. Deep-UV lithography is capable of pattern generation to dimensions of 0.2 &mgr;m or less and, when a resist material having low light absorption is used, can form patterns with sidewalls that are nearly vertical to the substrate. One technology that has attracted a good deal of attention recently utilizes a high-intensity KrF excimer laser as the deep-UV light source. Resist materials with low light absorption and high sensitivity are needed to successfully apply this technology to large-volume production.
In light of this, acid-catalyzed chemically amplified positive resist materials were recently developed as disclosed in JP-B 2-27660, JP-A 63-27829, U.S. Pat. Nos. 4,491,628 and 5,310,619. Because of their excellent properties including sensitivity, resolution and dry-etching resistance, they are especially promising as resist materials for deep-UV lithography.
Chemically amplified resist materials, however, suffer from a post-exposure delay (PED) problem and a footing phenomenon. The PED problem is that in lithographic process, line patterns would have a T-top profile, that is, patterns become thick at the top if the leave-to-stand or delay time from exposure to post-exposure baking (PEB) is extended. The footing is a phenomenon that a pattern on a basic substrate, especially silicon nitride or titanium nitride substrate becomes widened in proximity to the substrate. It is believed that the T-top profile arises because the solubility of resist film is reduced in proximity to its surface whereas the footing arises because the solubility of resist film is reduced in proximity to the substrate. There also occurs a problem that dark reaction of eliminating acid labile groups proceeds in a PED duration from exposure to PEB, reducing the dimension of lines to be left. These problems are serious enough to prevent chemically amplified positive resist materials from practical application. Moreover, these problems not only complicate dimensional control in the lithographic process, but also adversely affect dimensional control in the processing of substrates using dry etching. In this regard, reference is made to W. Hinsberg et al., J. Photopolym. Sci. Technol., 6 (4), 535-546 (1993) and T. Kumada et al., J. Photopolym., Sci. Technol., 6 (4), 571-574 (1993).
It is understood that in chemically amplified positive resist materials, air-borne basic compounds Largely participate in the PED problem and basic compounds on the substrate surface largely participate in the footing phenomenon. Light exposure generates acid at: the resist surface which is deactivated through reaction with air-borne basic compounds. As the leave-to-stand or delay time from exposure to PEB is extended, the amount of thus deactivated acid increases to retard decomposition of acid labile groups. An insolubilized layer is then formed at the resist surface, resulting in a T-top profile.
It is well known that the addition of basic compounds to resist materials is effective to suppress the influence of air-borne basic compounds, thereby improving PED (see U.S. Pat. No. 5,609,989, WO 98/37458, JP-A 63-149640, JP-A 5-113666, JP-A 5-232706 and JP-A 5-249683). Among such basic compounds, nitrogenous compounds are well known, typically amine and amide compounds having a boiling point of 150° C. or higher. Illustrative examples include pyridine, polyvinyl pyridine, aniline, N-methylaniline, N,N-dimethylaniline, o-toluidine, m-toluidine, p-toluidine, 2,4-lutidine, quinoline, isoquinoline, formamide, N-methylformamide, N,N-dimethyl-formamide, acetamide, N-methylacetamide, N,N-dimethylacet-amide, 2-pyrrolidone, N-methylpyrrolidone, imidazole, &agr;-picoline, &bgr;-picoline, &ggr;-picoline, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 2-quinoline-carboxylic acid, 2-amino-4-nitrophenol, and triazine compounds such as 2-(p-chlorophenyl)-4,6-trichloromethyl-s-triazine. Of these, pyrrolidone, N-methylpyrrolidone, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid and 1,2-phenylenediamine are often used.
These nitrogenous compounds are weakly basic and can mitigate the T-top problem, but fail to control reaction or acid diffusion when highly reactive acid labile groups are used. The addition of weak bases allows the dark reaction during PED to proceed to unexposed areas, incurring sliming of line size and film thinning on line surface during PED. This problem may be overcome by adding strong bases. However, a higher basicity does not always bring good results. No satisfactory results are obtained when proton sponge, DBN, and DBU, which are known as a ultra-strong base and shown below, or quaternary amines such as tetramethylammonium hydroxide are added.
To enhance contrast to achieve a high resolution, it is advantageous to add a base which is more effective for complementing the acid generated. While the dissociation constant of an acid or base in water is accounted for in terms of pKa, the ability of a base to complement acid in the resist film is not directly related to the pKa of the base. This fact is discussed in Hatayama et al., J. of Photopolymer Sci. and Technology, Vol. 13, No. 4, pp. 519-524 (2000).
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel amine compound which is effective for preventing a resist film from thinning and for expanding the focus margin while achieving an improved resolution. Another object is to provide a resist composition comprising the same and a patterning process using the composition.
The present inventor has found that amine compounds having a cyano group, specifically amine compounds having the following general formula (1), (2), (3) or (4), are fully effective for preventing a resist film from thinning and also effective for enhancing the resolution and focus margin of resist.
In a first aspect, the invention provides amine compounds of the following general formulae (1), (2), (3) and (4).
Herein R
1
is independently a straight or branched alkylene group of 1 to 4 carbon atoms; R
2
is independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms which may contain a hydroxy group, ether group, carbonyl group, ester group, lactone ring, carbonate or cyano group; R
3
is a straight or branched alkylene group of 2 to 20 carbon atoms which may contain a hydroxy group, ether group, thioether group, carbonyl group, ester group, thioester group or carbonate; R
4
is independently a straight or branched alkylene group of 1 to 4 carbon atoms; “a” is an integer of 1 to 3, and a+b=3.
In a preferred embodiment, R
2
in formulae (1) and (3) has the following general formula (5), (6), (7) or (8).
Herein R
5
, R
7
and R
10
each are a straight or branched alkylene group of 1 to 4 carbon atoms; R
6
and R
9
each are hydrogen or a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms which may contain a hydroxy group, ether group, ester group, lactone ring or cyano group; R
5
and R
6
, taken together, may form a ring with the oxygen atom; R
8
is a single bond or a straight or branched alkylene group of 1 to 4 carbon atoms; R
11
is a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms which may contain a hydroxy group, ether group, ester group or lactone ring; R
12
is a (n+1)-valent straight or branched organic group of 1 to 4 carbon atoms; R
13
is independently a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms which may contain an e

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