JPH07146558A - Photosensitive composition and pattern forming method using the same - Google Patents

Abstract

PURPOSE:To provide the photosensitive composition to be favorable used for a resist, high in sensitivity and resolution to a short wavelength light, not causing phase separation in a state of a film, and capable of stably forming a fine resist pattern. CONSTITUTION:This photosensitive composition.comprises a polymer obtained by protecting the alkali-soluble groups of an alakli-soluble polymer with groups instable to acid, a compound to be allowed to produce acid by irradiation of light, and at least one kind of compound for enhancing compatibility in the inside one time resist film selected from among imidazole, alanine, adenine, adenccsine, a quaternary ammonium salt, and an N-containing sugar compound, and a phenol compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition used for microfabrication of semiconductor devices, particularly large scale integrated circuits (LSI), and a pattern forming method.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device such as an LSI, a fine processing technique by photolithography is adopted.
Specifically, this technique is performed according to the following process. That is, first, a photoresist film is formed on a substrate such as a silicon single crystal wafer by, for example, a spin coating method. Next, after exposing this resist film, processing such as development and rinsing is performed to form a resist pattern. Then, the exposed wafer surface is etched using the resist pattern as an etching-resistant mask to open fine lines and windows to form a desired pattern.

In the manufacturing process of an LSI, a processing technique capable of forming a finer pattern is required in the lithography technique as the LSI is highly integrated.
In response to such a demand, attempts have been made to shorten the wavelength of the exposure light source. As a concrete measure, a lithography technique using deep UV as a light source such as a KrF excimer laser (wavelength 248 nm) and an ArF excimer laser (wavelength 193 nm) is being studied.

However, in the conventional resist material,
Since the absorption of deep UV is excessively large, a portion (eg,
UV light cannot sufficiently reach the interface region of the resist film in contact with the substrate. As a result, in the exposed portion of the resist film, chemical change due to exposure does not sufficiently occur over the entire film thickness, and the solubility in the developing solution in the film thickness direction becomes uneven. In particular, the solubility of the above-described portion of the resist film away from the surface is not sufficient, and the cross-sectional shape of the resist pattern formed after development becomes triangular. Therefore, when the obtained resist pattern is used as an etching resistant mask, a target fine pattern cannot be transferred to a substrate or the like, which is a problem.

As a resist material that solves such a problem, a chemically amplified resist has been proposed. A chemically amplified resist is a photosensitive compound containing a compound that generates a strong acid upon irradiation with light, that is, a photoacid generator and a compound that decomposes a hydrophobic group by the generated acid and changes to a hydrophilic substance. It is a composition. Specifically, H.264. It
O, C, G, Wilson, J. et al. M. J. Freche
U.S. Pat. No. 4,491,628 (1985),
A positive resist containing a polymer obtained by blocking a hydroxyl group of poly (p-hydroxystyrene) with a butoxycarbonyl group and an onium salt as a photoacid generator is disclosed. In addition, M. J. O'Brien, J .; V. Criv
ello, SPIE Vol, 920, Advance
s inResist Technology and
Processing, p42, (1988),
A positive resist containing m-cresol novolac resin, naphthalene-2-carboxylic acid-tert-butyl ester, and triphenylsulfonium salt as a photoacid generator is disclosed. Furthermore, H. Ito, SPIE Vol, 920,
Advances in Resist Techno
logy and Processing, p33, (1
988) includes 2,2-bis (4-tert-butoxycarbonyloxyphenyl) propane and polyphthalaldehyde,
A positive resist containing an onium salt as a photoacid generator is disclosed.

In these chemically amplified resists, the acid generated from the photo-acid generator functions as a catalyst, and even a small amount of the chemical efficiently causes a chemical change inside the resist. as a result,
When the resist film is exposed, the reaction sufficiently progresses even in the inside of the film where the radiation is hard to reach compared to the film surface. As a result, after the development processing, it becomes possible to form a resist pattern having a rectangular cross section, in particular, a steep and vertical side surface of the line portion.

However, in the above-mentioned chemically amplified resist, since the amount of acid generated in the exposed portion of the resist film is very small, the influence of oxygen, moisture and other trace components in the surrounding environment, especially in the atmosphere on the surface of the resist film is affected. It is easily received and cannot stably form a fine pattern. Specifically, a small amount of dimethylaniline contained in the atmosphere,
In order to deactivate the acid generated near the surface of the resist film by light irradiation, the dissolution rate in the developer is significantly reduced, a so-called sparingly soluble layer is formed on the resist film surface, the sparingly soluble layer, It has been reported that the surface of the resist pattern remains in an eaves-like shape after exposure and development (SA MacDonald, NJ Clear.
k, H .; R. Werdt, C.I. G. Willson,
C. D. Snyder, C.I. J. Knors, N.M. B.
Deyoe, J .; G. Maltas, J .; R. Mo
rrow, A .; E. McGuire and S.M. J.
Hplmes, Proc. SPIE, Vol. 146
6, 2 (1991)).

This poorly soluble layer lowers the resolution of the resist, and the eaves generated in the resist pattern due to this decrease,
It adversely affects the etching accuracy of the semiconductor substrate region. In order to prevent the formation of this eaves-like insoluble layer, a protective film 8 is formed on the resist film to reduce the influence of the outside air as shown in FIG. 3A, and then exposure is performed. . However, even in this case, the eaves could not be completely removed, and the eaves-like insolubilized layer 9 as shown in FIG. 3B was formed on the side wall of the obtained resist pattern 6.

When patterning is performed using the above-described chemically amplified resist, when forming a resist film,
That is, when the resist solution is applied onto the substrate, phase separation may occur in the film due to the difference in the molecular weight of the components, resulting in non-uniform concentration distribution of the components. As a result, the chemical change does not proceed uniformly in the exposed portion of the film, and a fine resist pattern having a rectangular cross section cannot be stably obtained.

Regarding the phase separation among these, specifically, H. Ito, J. Polymer. Sci. : Pa
rt A 24, 2971 (1986), a phenolic hydroxyl group used as a component of a resist material is
It has been reported that in the synthesis of polyvinylphenol partially protected by tert-butoxycarbonyl, phase separation occurs depending on the introduction ratio of the protective group of the polymer. Regarding the concentration distribution of components in the resist film, specifically, M. Toriumi, M .;
Yanagimachi and H.M. Masuhar
a, Proc. SPIE, Vol. 1466,458
(1991).

Furthermore, as a problem in using chemically amplified resists, it is known that the tolerance for the time between exposure and post-exposure bake is generally small. This is because the acid generated from the photo-acid generator upon exposure immediately diffuses in the resist film due to the action of the residual solvent.
In order to avoid this problem, currently, as a measure on the apparatus side, measures such as re-prioritizing the process between exposure and post-exposure bake are taken, but the dimensional fluctuation is still sufficiently suppressed. The current situation is not.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has high sensitivity and high resolution particularly for a light source having a short wavelength, and is capable of performing phase separation in a film state. An object of the present invention is to provide a photosensitive composition that does not occur and is hardly affected by the surrounding atmosphere and that can stably obtain a fine resist pattern.

[0013]

The object of the present invention is solved by a photosensitive composition according to the first invention and a photosensitive composition according to the second invention described below.

The photosensitive composition according to the first invention is (a)
A polymer in which an alkali-soluble group of an alkali-soluble polymer is protected by an acid-labile group, (b) a compound which generates an acid upon irradiation with light, and (c) an imidazole compound, an alanine compound, an adenine compound, and adenosine At least one compound selected from the group consisting of a compound, a quaternary ammonium salt compound, and a nitrogen-containing saccharide compound, which is characterized by containing a compound that enhances compatibility in the resist film.

The photosensitive composition according to the second invention is (a)
A polymer obtained by protecting an alkali-soluble group of an alkali-soluble polymer with an acid-labile group, (b) a compound which generates an acid upon irradiation with light, (c) an imidazole compound, an alanine compound, an adenine compound, an adenosine compound At least one compound selected from the group consisting of a quaternary ammonium salt compound and a nitrogen-containing saccharide compound, which contains a compound that enhances compatibility in the resist film, and (d) a phenol compound. To do.

The manufacturing method of the present invention comprises the steps of forming a resin layer containing the photosensitive composition according to the first and second inventions as a main component on a substrate, subjecting the resin layer to pattern exposure, The method is characterized by comprising a step of baking the resin layer after exposure and a step of developing the resin layer after baking using an alkaline solution as a developing solution.

The present invention will be described in detail below.

The polymer which is the component (a) in the photosensitive composition according to the first invention comprises an alkali-soluble polymer as a base polymer, and an alkali-soluble group in the base polymer such as a phenolic hydroxyl group and a carboxyl group, A compound protected by an acid labile group (protecting group) to suppress its alkali affinity. Such a polymer was substantially insoluble in an alkaline solution in the unexposed state, but during exposure, the protecting group was decomposed by the acid generated from the component (b), and was provided in the base polymer. Since the alkali-soluble group is regenerated, the compound changes to a compound exhibiting alkali solubility. The molecular weight of this polymer is preferably about 1,000 or more from the viewpoint of improving heat resistance.

As the polymer of the component (a), an ether or ester having an alkali-soluble polymer having a phenol skeleton as a base polymer can be preferably used. Specifically, a compound in which a phenolic hydroxyl group of a polymer having a phenol skeleton is protected by treatment with a suitable etherifying agent or esterifying agent and esterification or esterification is mentioned.

Examples of the alkali-soluble polymer having a phenol skeleton include phenol, cresol, xylenol, bisphenol A, bisphenol S, hydroxybenzophenone, 3,3,3 ', 3'-tetramethyl-1,1'-spirobiindane. -5,6,7,5 ', 6', 7'-hexanol, a polymer having phenolphthalein as a monomer unit, a polyvinylphenol, and a novolac resin are included.

The ether and ester introduced into the alkali-soluble polymer having a phenol skeleton as a protecting group include, for example, tetrahydropyranyl ether, benzyl ether, methyl ether, ethyl ether, n-propyl ether and iso-propyl. Ether, tert-butyl ether, allyl ether, methoxymethyl ether, p-bromophenacyl ether, trimethylsilyl ether, benzyloxycarbonyl ether, tert-butoxycarbonyl ether, tert-butyl acetate, 4-tert-butylbenzyl ether, methyl ester, Ethyl ester, n-propyl ester, iso-
Examples thereof include propyl ester, tert-butyl ester, n-butyl ester, iso-butyl ester, benzyl ester and the like.

In the above-mentioned polymer, all the phenolic hydroxyl groups in the base polymer are not protected and some remain. Therefore, this polymer is substantially a copolymer composed of a monomer unit having an ether or ester introduced therein and a monomer unit having a phenolic hydroxyl group.

As the polymer of the component (a), compounds represented by the formulas (1) to (4) shown in the following chemical formula 1 are particularly preferable.

[0024]

[Chemical 1] In the formula, R ¹ , R ² and R ³ represent a monovalent organic group, and m and n are positive integers representing a copolymer composition. m and n
Preferably has a protection rate represented by (n / (m + n)) of 1 or more and 100 or less, more preferably 5 or more and 60 or less. In addition, as the monovalent organic group,
Although not particularly limited, examples thereof include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, iso-butyl, sec-butyl, benzyl and the like.

The content of the component (a) is preferably 5 to 80% by weight based on the total solid components of the composition, and 10 to 6 is preferable.
It is more preferably 0% by weight.

The component (b) in the photosensitive composition according to the first invention is a compound that generates an acid upon exposure, and corresponds to a photoacid generator of a chemically amplified resist. Such compounds include compounds and mixtures known as photoacid generators, such as onium salts, organohalogen compounds, orthoquinones.
-Diazide sulfonic acid chloride, sulfonic acid esters and the like can be used.

Examples of the onium salt include CF ₃
SO ₃ ⁻ , p-CH ₃ PhSO ₃ ⁻ , p-NO ₂ PhS
Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts having O ₃ ⁻ (wherein Ph is a phenyl group) as a counter anion.

The organic halogen compound is a compound that forms a hydrohalic acid, and is, for example, US Pat. No. 3,515,552 and US Pat. No. 3,536,48.
No. 9, U.S. Pat. No. 3,779,778, and West German Patent Publication No. 2,243,621.

Examples of photoacid generators other than those mentioned above include, for example, JP-A-54-74728 and JP-A-55-241.
13, JP-A-55-77742, JP-A-60-36.
26, JP-A-60-138539, JP-A-56-1
7345 and the compounds disclosed in JP-A-50-36209.

Specific examples of such compounds include di (p-tertiarybutylbenzene) iodonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, benzointosylate, orthonitrobenzyl paratoluenesulfonate,
Triphenylsulfonium trifluoromethanesulfonate, tri (tertiarybutylphenyl) sulfonium trifluoromethanesulfonate, benzenediazonium paratoluenesulfonate, 4- (di-n-propylamino) -benzonium tetrafluoroborate, 4-p-tolyl-mercapto-2 , 5-Diethoxy-benzenediazonium hexafluorophosphate, tetrafluoroborate, diphenylamine-4-diazonium sulfate,
4-methyl-6-trichloromethyl-2-pyrone, 4- (3,4,5-
Trimethoxy-styryl) -6-trichloromethyl-2-pyrone, 4- (4-methoxy-styryl) -6- (3,3,3-trichloro-propenyl) -2-pyrone, 2-trichloromethyl-benzimidazole, 2-tribromomethyl-quinoline, 2,
4-Dimethyl-1-tribromoacetyl-benzene, 4-dibromoacetyl-benzoic acid, 1,4-bis-dibromomethyl-
Benzene, tris-dibromomethyl-S-triazine, 2-
(6-Methoxy-naphthyl-2-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (naphthyl-1-yl)-
4,6-bis-trichloromethyl-S-triazine, 2- (naphthyl-2-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-ethoxyethyl-naphthyl-1-yl) -Four,
6-bis-trichloromethyl-S-triazine, 2- (benzopyranyl-3-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-methoxy-anthrac-1-yl) -4, 6-
Examples include bis-trichloromethyl-S-triazine, 2- (phenanth-9-yl) -4,6-bis-trichloromethyl-S-triazine, o-naphthoquinonediazide-4-sulfonic acid chloride and the like. As the sulfonic acid ester, naphthoquinone diazide-4-sulfonic acid ester, naphthoquinone diazide
-5-sulfonic acid ester, p-toluenesulfonic acid-o-nitrobenzyl ester, p-toluenesulfonic acid-2,6-dinitrobenzyl ester and the like can be mentioned.

The amount of the above-mentioned component (b) is preferably about 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, based on the total solid components of the composition. If the content of the component (b) is less than 0.01% by weight, it may be difficult to obtain sufficient photosensitivity. On the other hand, 50% by weight
If it exceeds, it may be difficult to form a uniform resist film, or a residue may be generated during removal after pattern formation.

In the photosensitive composition according to the first invention, the component (c) is a compound that enhances the compatibility in the resist film, and includes an imidazole compound, an alanine compound, an adenine compound, an adenosine compound, a quaternary ammonium salt compound and It is selected from nitrogen-containing sugar compounds.

Here, the imidazole compound is imidazole or a derivative thereof. Specific examples thereof include a compound represented by the formula (5) shown in Chemical formula 2 below.

[0034]

[Chemical 2] In the formula, R ⁴ represents a monovalent organic group.

The alanine compound is alanine or its derivative. Specific examples thereof include a compound represented by the formula (6) shown in Chemical Formula 3 below.

[0036]

[Chemical 3] In the formula, R ⁵ represents a monovalent organic group.

The adenine compound is adenine or its derivative. Specific examples thereof include compounds represented by formula (7) and formula (8) shown below.

[0038]

[Chemical 4] In the formula, R ⁶ and R ⁷ each represent a monovalent organic group.

The adenosine compound is adenosine or its derivative. A specific example is shown below.
And a compound represented by the formula (9).

[0040]

[Chemical 5] In the formula, R ⁸ represents a monovalent organic group.

In the compounds of formulas (5) to (9), the monovalent organic group introduced as R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ is not particularly limited. However, examples thereof include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, iso-butyl, sec-butyl and benzyl.

The quaternary ammonium salt compound is a quaternary ammonium salt or its derivative. Specific examples thereof include a compound represented by the formula (10) shown below. In the formula, R ⁹ represents a monovalent organic group, and X
Examples thereof include monovalent organic groups, and hydroxyl groups are preferable.

[0043]

[Chemical 6] The nitrogen-containing saccharide compound is represented by the following formula (11)
A compound having a nitrogen-containing substituent bonded to the skeleton as shown in.

[0044]

[Chemical 7] Specific examples thereof include chitin and chitosan.

In the photosensitive composition of the first invention, the amount of the above-mentioned component (c) is preferably about 0.01 to 50% by weight, more preferably 0.1 to 50% by weight based on the total solid components of the composition.
It is 30% by weight. The compounding amount of the component (c) is 0.01
If it is less than 50% by weight, a residue may be generated after the development treatment and the surface of the pattern to be formed may be roughened. The difference in speed becomes smaller,
The resolution may decrease.

The photosensitive composition of the second invention will be described in detail below.

The photosensitive composition according to the second invention contains a phenol compound as the component (d) in addition to the components (a), (b) and (c).

The phenol compound as the component (d) is a compound having a phenol skeleton, that is, a phenolic hydroxyl group in the structure. As such a phenol compound, it is preferable to use a compound having a lower molecular weight than that of the polymer as the component (a), particularly an ether or ester having a polymer having a phenol skeleton as a base polymer.

Specific examples of the phenol compound include:
Formula (12), Formula (13), and Formula (1
And a compound represented by the formula (15)
The polyvinyl phenyl represented by Among these, a triphenol compound, that is, a compound having three phenolic hydroxyl groups is particularly preferable, and a compound represented by the formula (15)
In the case of polyvinylphenol represented by, it is preferable that p has a lower molecular weight than the base polymer having a phenol skeleton.

[0050]

[Chemical 8]

[Chemical 9] In the photosensitive composition according to the second invention, the blending amount of the component (d) is preferably about 0.01 to 50% by weight, more preferably 0.1 to 10% by weight based on the total solid components of the composition.
The range is wt%. The content of the component (d) is 0.0
If it is less than 1% by weight, it may be difficult to obtain sufficient photosensitivity, while if it exceeds 50% by weight, it may be difficult to form a uniform resist film.

In the photosensitive composition according to the second invention, the components (a), (b) and (c) are compounded in amounts of 10 to 60% by weight and 0.1 to 10% by weight, respectively. %,
And 5 to 50% by weight is preferable.

In addition to the above essential components, the photosensitive composition of the present invention may further contain, if necessary, a surfactant as a film modifier and a dye as an antireflection agent. Good.

The photosensitive composition of the present invention can be prepared by dissolving the above-mentioned essential components and, if necessary, other additives in a suitable organic solvent and filtering. As the organic solvent used here, for example, cyclohexanone, acetone, methyl ethyl ketone, a ketone solvent such as methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, cellosolve solvent such as butyl cellosolve acetate, acetic acid. Examples thereof include ester solvents such as ethyl, butyl acetate, isoamyl acetate, ethyl lactate and methyl lactate, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide and dimethylsulfoxide. These solvents may be used alone or in the form of a mixture. Further, these solvents may contain an appropriate amount of an aliphatic alcohol such as xylene, toluene or isopropyl alcohol.

Next, the process of forming a resist pattern using the photosensitive composition of the present invention will be described.

First, a solution of a photosensitive composition prepared by dissolving the above components in an organic solvent is applied onto a substrate by a spin coating method or a dipping method, and then the temperature is about 150 ° C. or lower, preferably 70 to 120 ° C. And dried to form a photosensitive resin layer (resist film) containing the above composition as a main component.
The substrate used here is, for example, a silicon wafer, a silicon wafer having a stepped surface on which various insulating films and electrodes are formed, a blank mask, GaAs, and AlG.
Examples thereof include III-V compound semiconductor wafers such as aAs.

Next, pattern exposure is performed on the resist film. At this time, in the exposed portion of the resist film, acid is generated from the component (b) of the photosensitive composition.

The light source for such exposure is, for example, i-line, h-line, g-line of a low-pressure mercury lamp, xenon lamp light,
DeepUV such as KrF or ArF excimer laser
Various kinds of ultraviolet rays such as X-rays, electron beams, γ-rays, and ion beams can be used. As a specific method of pattern exposure, when ultraviolet rays or X-rays are used, the resist film is selectively exposed through a predetermined mask pattern. On the other hand, when an electron beam, an ion beam, or the like is used, these resist films are scanned without using a mask to directly perform pattern exposure on the resist film. Incidentally, in order to slow down the dissolution rate of the unexposed portion and improve the resolution, it is possible to perform fogging exposure by exposing the entire surface of the resist film while heating the pattern exposed portion.

Subsequently, the resist film after exposure is heat-treated (baked) using a hot plate, an oven, or by infrared irradiation. By such baking, in the exposed portion of the resist film, the acid generated at the time of exposure diffuses and acts on the polymer of component (a) to decompose the introduced protecting group to regenerate the alkali-soluble group.

The baking temperature is preferably about 5.
The temperature is set to 0 to 160 ° C, more preferably 70 to 150 ° C. When the temperature is less than 50 ° C., the component (b)
The acid generated from the above may not be sufficiently reacted with the component (a), and if the temperature exceeds 160 ° C., excessive decomposition or curing may occur over the exposed and unexposed areas of the resist film. is there.

Next, the resist film after baking is subjected to a developing treatment using an alkaline solution by a dipping method, a spray method or the like to selectively dissolve and remove the exposed portion of the resist film to obtain a desired pattern. Examples of the alkaline solution used as the developing solution here include an inorganic alkaline solution such as an aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, a tetramethylammonium humanoxy solution, and trimethylhydroxy. Examples thereof include an aqueous solution of ethylammonium hydroxy, or a solution obtained by adding alcohol, a surfactant or the like to these.

The developed substrate and resist film (resist pattern) are rinsed with water or the like and then dried.

In the above process, in order to further improve the heat resistance of the resist pattern, the resin component (polymer of component (a)) in the resist pattern is removed by gradually heating the substrate after the development treatment. Step baking such as crosslinking or deepU while heating
Deep UV, in which V is irradiated to crosslink the resin component (polymer of component (a)) in the resist pattern
It is also possible to perform processing such as curing.

In order to further reduce the dissolution rate of the unexposed portion of the resist film in the alkaline solution and improve the contrast with the exposed portion, the resist film is immersed in a low-concentration alkaline solution before or after the exposure, Subsequently, the development processing may be performed using an alkaline solution having a higher concentration. In this case, the resist film can be immersed in amines such as triethylamine, triethanolamine, hexamethyldisilazane, etc. instead of the low-concentration alkaline solution, or the resist film can be exposed to the vapor of these amines. Furthermore, the resist film exposed to a low-concentration alkaline solution or amines can be heat-treated as necessary.

[0064]

The photosensitive composition of the present invention corresponds to a positive chemically amplified resist. That is, when the photosensitive composition is applied to the pattern forming process, an acid is generated from the component (b) in the exposed portion, and the acid acts catalytically by baking to be introduced into the component (a). It decomposes acid labile groups to give alkali-soluble groups.
As a result, in the component (a), the exposed part has an increased alkali solubility, that is, a dissolution rate in an alkali solution, and thus the exposed part is selectively dissolved and removed by a development treatment using an alkali solution. In this way, a fine pattern having lines and spaces of a predetermined width can be formed with high sensitivity and high resolution.

The photosensitive composition according to the first invention comprises, in addition to the above components (a) and (b), a component (c), that is, an imidazole compound, an alanine compound, an adenine compound, an adenosine compound, a quaternary ammonium salt. It contains at least one compound selected from the group consisting of compounds and nitrogen saccharide compounds. Since the component (c) enhances the compatibility of the polymer of the component (a) and the low molecular weight compound of the component (b), phase separation does not occur in the state of the membrane. That is, the concentration distribution of each component becomes constant over the entire film, chemical changes due to exposure and the like are promoted, and it is possible to prevent the formation of the eaves-like insolubilized layer without forming a protective film on the resist film. it can.

Therefore, the photosensitive composition according to the first invention retains the high sensitivity and high resolution peculiar to a chemically amplified resist, and is stable throughout the pattern formation process, and has a fine rectangular cross section. A pattern can be provided. Further, the step of forming the protective film can be omitted.

In particular, the above-mentioned component (c) can prevent the resist composition of the present invention from diffusing the acid generated from the photo-acid generator upon exposure. Therefore, it is possible to suppress the dimensional variation regardless of the standing time.

The photosensitive composition according to the second invention comprises, in addition to the components (a), (b) and (c) of the first composition,
A phenol compound is used in combination as the component (d). Since the components (c) and (d) further enhance the compatibility of the polymer of the component (a) and the low molecular weight compound of the component (b), the occurrence of phase separation in the state of the membrane is prevented. Further, the combination of the components (c) and (d) remarkably increases the dissolution rate of the film in the exposed portion with respect to the alkaline solution, so that the formation of the poorly soluble layer on the surface is suppressed, and further, the exposed portion and the unexposed portion The contrast is improved. Further, the component (d), which is a phenolic compound, can control the solubility in an alkaline developer and thus can reduce the generation of standing waves.

Therefore, the photosensitive composition according to the second invention retains the high sensitivity and high resolution peculiar to the chemically amplified resist, and has a pattern formation more than the composition according to the first invention. Stable throughout the process. Therefore, in addition to preventing the formation of the eaves-like hardly soluble layer on the surface,
Further, it is possible to reduce and eliminate the standing wave effect on the side surface thereof, and it is possible to widen the margin of the depth of focus, whereby it is possible to provide a pattern having a fine rectangular cross section.

[0070]

EXAMPLES The present invention will be described in detail below with reference to examples. These examples are described for the purpose of facilitating the understanding of the present invention, and do not limit the present invention in particular.

Synthesis of Polymer Introducing Acid-Instable Group In a nitrogen-substituted four-neck flask, 50 g of polyvinylphenol (PHM-C manufactured by Maruzen Petrochemical Co., Ltd.) was dissolved in 200 ml of acetone, Add 1 part potassium carbonate to this solution.
7.63 g, potassium iodide 8.48 g, and tert-butyl bromoacetate 24.38 g were added, and the mixture was refluxed for 7 hours with stirring. Subsequently, the insoluble matter was removed by filtration, the acetone was distilled off, and the remainder was ethanol 1.
Dissolved in 50 ml. This solution was dropped into 1.5 ml of water to precipitate a polymer. The polymer was collected by filtration, washed 5 times with 300 ml of water, and then dried for 12 hours. Then, the polymer after drying is again treated with ethanol 220.
It was dissolved in ml, reprecipitated and purified by the same operation as above, and then dried in a vacuum dryer at 50 ° C. for 24 hours to obtain 52.0 g of a polymer.

By analyzing the obtained polymer by ¹ H-NMR spectrum, it was confirmed that 15% of all the phenolic hydroxyl groups of polyvinylphenol was a compound in which tert-butoxycarbonylmethyl ether was changed. Let this polymer be [T-1].

Further, according to the same method as described above, by appropriately adjusting the compounding amounts of potassium carbonate, potassium iodide, and tert-butyl bromoacetate, the substitution ratio of the phenolic hydroxyl group in polyvinylphenol, that is, the ether Eight types of polymers [T-2] to [T-9] having different introduction rates were synthesized.

The structures and compositions of these polymers are shown in Table 1 below.
Shown in.

[0075]

[Table 1] Examples 1 to 66 (1) Preparation of Photosensitive Composition According to the formulations shown in Tables 2 to 8 below, a polymer in which an acid labile group was introduced and an onium salt (triphenylsulfonium) as a photoacid generator were prepared. Triflate) and an amine compound and / or a phenol compound are dissolved in an organic solvent, and this solution is filtered through a filter having a pore size of 0.2 micron to obtain photosensitive compositions [R-1] to [R-1]. −
66] was prepared as a varnish.

In the preparation of these photosensitive compositions, in the compositions [R-1] to [R-9], the imidazole compound (A
-1 to A-3), alanine compounds (A-4 and A-5) in [R-10] to [R-21], and [R-22] to
[R-33] is an adenine compound (A-6 and A-7)
In [R-34] to [R-39], the adenosine compound (A-8), in [R-40] to [R-48], the quaternary ammonium salt compound (A-9), and [R- 49] ~ [R
-57], chitin (A-1
0) and [R-58] to [R-66] were blended with chitosan (A-11) as a nitrogen sugar compound.

Following the table, the structures of imidazole compounds, alanine compounds, adenine compounds, adenosine compounds, quaternary ammonium salt compounds, and nitrogen-containing saccharide compounds, which are indicated by abbreviations, are shown.

[0078]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Chemical 10]

[Chemical 11]

[Chemical 12] (2) Pattern formation Each of the photosensitive compositions (varnishes) prepared as described above,
A 6-inch silicon wafer was spin-coated and prebaked at 95 ° C. for 90 seconds on a hot plate to form a 1.0 μm thick photosensitive composition film (resist film). Subsequently, this resist film was pattern-exposed using a KrF excimer laser stepper, and then baked on a hot plate at 95 ° C. for 90 seconds. Next, the baked wafer was immersed in a tetramethylammonium hydroxide aqueous solution (TMAH aqueous solution) for 20 seconds to develop the resist film, washed with water and dried to obtain a pattern consisting of lines and spaces. In addition, T
The concentration of the MAH aqueous solution is the composition [R-1] to [R-4].
8] is applied to the resist film at 1.59%,
The resist film coated with the compositions [R-49] to [R-66] was 2.38%.

Regarding the pattern thus formed,
The cross-sectional shape was observed using a scanning electron microscope, and the line and space widths were measured as the resolution.

The exposure amount (sensitivity) and resolution of the photosensitive composition in each example are shown in Tables 9 to 15 below.

[0081]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15] From the above results, it is clear that the photosensitive composition of the present invention has high sensitivity and high resolution. In addition, for any of the compositions, the cross section of the obtained pattern was rectangular, and the side surface of the line portion was steep.

When a pattern is formed using the above-mentioned compositions [R-1] to [R-66], the formation of an eaves-like hardly soluble layer on the resist surface is reduced and removed as shown in FIG. We were able to. Therefore, it becomes possible to form a pattern without forming a protective film on the resist film.

(3) Evaluation of influence of leaving time (delaying after exposure) The above-mentioned photosensitive composition [R-1] was spin-coated on a 6-inch silicon wafer, and 90 ° C. on a hot plate at 95 ° C. Prebaking was performed for 2 seconds to form a photosensitive composition film having a thickness of 1 μm. Subsequently, pattern exposure was performed on this resist film using a KrF excimer laser stepper. Here, the pattern dimensions were 0.4 μm, 0.3 μm, and 0.275 μm. After that, the exposed wafer was left for a predetermined time at the interface portion between the exposure device and the coating / developing device. Leaving time is 0, 1, 3, 5,
It was set to 10, 15, 20, 30, 60, and 120 minutes.
After that, baking is performed at 95 ° C. for 90 seconds, and immersion is performed in a 2.38% TMAH aqueous solution for 20 seconds to perform development processing.
After washing with water and drying, a pattern consisting of lines and spaces was obtained.

The cross-sectional shape of the pattern thus formed was observed by SEM, and the dimensional variation was measured for each pattern. The obtained results are shown by the curves a to c in FIG.

Further, as a comparative example, a photosensitive composition prepared in the same composition as [R-1] was used, except that a compound for enhancing the compatibility in the resist film was not contained, and the same procedure as described above was used. A 0.3 μm pattern was formed. The cross-sectional shape of the obtained pattern was observed by SEM, and its dimensional variation was measured. The pattern dimension at the same leaving time is
This is shown by the curve d in FIG.

As shown in FIG. 4, the composition containing no compound that enhances the compatibility in the resist film has a large dimensional variation, whereas the composition containing the compound that enhances the compatibility in the resist film of the present invention. The photosensitive composition can suppress dimensional variation regardless of the standing time. From this,
It can be seen that the addition of the compound that enhances the compatibility in the resist film suppresses the diffusion of the acid generated by the photo-acid generator.

Examples 67 to 182 (1) Preparation of Photosensitive Composition According to the formulations shown in Tables 16 to 27 below, a polymer having an acid-labile group introduced therein, and an onium salt ( Triphenylsulfonium triflate), a compound that enhances the compatibility in the resist film, and a phenol compound are dissolved in an organic solvent, and the solution has a pore size of 0.2.
Photosensitive compositions [R-67] to [R-182] were prepared in the form of varnish by filtering through a micron filter.

In the preparation of these photosensitive compositions, as the phenol compound, (P-1) shown in the following Chemical formula 13 and (P-8) shown in the following chemical formula 14 were used. In addition, (P-
Polyvinylphenol of 8) has a molecular weight of 6000.
Something was used. Further, as the compound for increasing the compatibility in the resist film, the compositions [R-67] to [R-8]
6], the imidazole compound (A-1) was added to [R-8
7] to [R-106] are alanine compounds (A-4)
In [R-107] to [R-116], the adenine compound (A-6), in [R-117] to [R-126], the adenine compound (A-7), and in [R-127] to [R-
146], an adenosine compound (A-8) was added to [R-1
47] to [R-164] are quaternary ammonium salt compounds (A-9), and [R-165] to [R-173] are chitin (A-10) as a nitrogen-containing saccharide compound, and [R-
174] to [R-182] used chitosan (A-11) as a nitrogen-containing saccharide compound.

[0089]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

[Table 21]

[Table 22]

[Table 23]

[Table 24]

[Table 25]

[Table 26]

[Table 27]

[Chemical 13]

[Chemical 14] (2) Pattern formation Each of the photosensitive compositions (varnishes) prepared as described above,
A 6-inch silicon film was spin-coated and prebaked on a hot plate at 95 ° C. for 90 seconds to form a 1.0 μm-thick photosensitive composition film (resist film). Subsequently, this resist film was pattern-exposed using a KrF excimer laser stepper, and then baked on a hot plate at 95 ° C. for 90 seconds. Then, the baked wafer was immersed in a TMAH aqueous solution having a concentration of 1.59% for 20 seconds to develop the resist film, washed with water and dried to obtain a pattern composed of lines and spaces.

Regarding the pattern thus formed,
The cross-sectional shape was observed using a scanning electron microscope, and the line and space widths were measured as the resolution.

The exposure amount (sensitivity) and resolution of the photosensitive composition in each example are shown in Tables 28 to 39 below.

[0092]

[Table 28]

[Table 29]

[Table 30]

[Table 31]

[Table 32]

[Table 33]

[Table 34]

[Table 35]

[Table 36]

[Table 37]

[Table 38]

[Table 39] From the above results, it is clear that the photosensitive composition of the present invention has high sensitivity and high resolution. In addition, for any of the compositions, the cross section of the obtained pattern was rectangular, and the side surface of the line portion was steep.

These Examples [R-67] to [R-18]
When a pattern was formed using the composition of [2], it was possible to reduce the generation of standing waves on the side surface of the pattern as shown in FIG. Therefore, it becomes possible to perform pattern formation more accurately.

Comparative Example 1 A polymer having an acid labile group introduced therein [T
-1] 2.0 g and 30 mg of an onium salt (triphenylsulfonium triflate) as a photoacid generator were dissolved in 6.00 g of ethylcerolbuacetate, and this solution was passed through a filter having a pore size of 0.2 micron. Filtered,
Photosensitive composition [R-190] was prepared in the form of varnish.

Using the photosensitive composition [R-190], pattern formation was carried out according to the same method and conditions as in the above-mentioned Examples.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, and the widths of lines and spaces were measured as the resolution. The exposure amount was 40 mJ.
The resolution was 0.35 μm at / cm ² . However, an eaves-like hardly soluble layer was formed in the surface layer portion of this pattern. It is considered that this is because the photosensitive composition [R-190] did not contain the specific amine compound or phenolic compound as in the above Examples.

Comparative Example 2 A polymer having an acid labile group introduced therein [T
-5] 2.0 g and 30 mg of an onium salt (triphenylsulfonium triflate) as a photoacid generator were dissolved in 6.00 g of methyl methoxypropionate, and this solution was filtered through a filter having a pore size of 0.2 micron. The mixture was filtered through to prepare a photosensitive composition [R-191] in the form of varnish.

Using the photosensitive composition [R-191], pattern formation was carried out according to the same method and conditions as in the above-mentioned Examples.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, and the widths of lines and spaces were measured as the resolution. The exposure dose was 43 mJ.
The resolution was 0.40 μm at / cm ² . However, an eaves-like hardly soluble layer was formed in the surface layer portion of this pattern. It is considered that this is because the photosensitive composition [R-191] did not contain the specific amine compound or phenol compound as in the above Examples.

Comparative Example 3 A polymer having an acid labile group introduced therein [T
-1] 2.0 g and 40 mg of an onium salt (triphenylsulfonium triflate) as a photoacid generator were dissolved in 6.00 g of ethylrosolve acetate, and this solution was passed through a filter having a pore size of 0.2 micron. And filtered to prepare a photosensitive composition [R-192] in the form of a varnish.

Using the photosensitive composition [R-192], pattern formation was carried out according to the same method and conditions as in the above-mentioned Examples.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, and the widths of lines and spaces were measured as the resolution. The exposure amount was 40 mJ.
The resolution was 0.40 μm at / cm ² . However, an eaves-like hardly soluble layer was formed in the surface layer portion of this pattern. It is considered that this is because the photosensitive composition [R-192] did not contain the specific amine compound or phenol compound as in the above Examples.

Comparative Example 4 Acid-labile group-introduced polymer [T
-1] 2.0 g and 30 mg of an onium salt (triphenylsulfonium triflate) as a photoacid generator were dissolved in 6.00 g of methyl methoxypropionate, and this solution was passed through a filter having a pore size of 0.2 micron. And filtered to prepare a photosensitive composition [R-193] in the form of a varnish.

Using the photosensitive composition [R-193], pattern formation was carried out according to the same method and conditions as in the above-mentioned Examples.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, and the line and space widths were measured as the resolution. The exposure amount was 40 mJ.
The resolution was 0.30 μm at / cm ² . However, in this case, an eaves-like hardly soluble layer was formed in the surface layer portion of this pattern. It is considered that this is because the photosensitive composition [R-193] did not contain the specific amine compound or phenol compound as in the above-mentioned Examples.

Comparative Example 5 Acid-labile group-introduced polymer [T
-1] 2.0 g and 40 mg of an onium salt (triphenylsulfonium triflate) as a photoacid generator were dissolved in 6.00 g of methyl methoxypropionate, and this solution was passed through a filter having a pore size of 0.2 micron. And filtered to prepare a photosensitive composition [R-194] in the form of a varnish.

Using the photosensitive composition [R-194], pattern formation was carried out according to the same method and conditions as in the above-mentioned Examples.

The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope, and the line and space widths were measured as the resolution. The exposure amount was 40 mJ.
The resolution was 0.40 μm at / cm ² . However, in this case, an eaves-like hardly soluble layer was formed in the surface layer portion of this pattern. It is considered that this is because the photosensitive composition [R-194] did not contain the specific amine compound or phenol compound as in the above-mentioned Examples.

[0109]

As described in detail above, according to the present invention,
In particular, it has high sensitivity and high resolution for a light source with a short wavelength, does not cause phase separation in the state of the film, and is not easily affected by the surrounding atmosphere. A photosensitive composition capable of forming a fine pattern is provided. The photosensitive composition may employ the process employed in conventional positive resists, such as deep UV cure to improve image contrast,
By performing these, the tolerance of process control such as exposure and development can be increased. Therefore, the photosensitive composition and the formation of a resist pattern using the photosensitive composition have a remarkable effect in the photolithography technique of the semiconductor device manufacturing process, and the industrial value thereof is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic view showing a pattern shape formed by a photosensitive composition of the present invention.

FIG. 2 is a schematic view showing a pattern shape formed by the photosensitive composition of the present invention.

FIG. 3 is a schematic view showing a pattern shape formed by a conventional photosensitive composition.

FIG. 4 is a diagram showing a relationship between a standing time and a pattern dimension variation.

[Explanation of symbols]

1 ... Substrate, 2 ... Resist pattern, 3 ... Substrate, 4 ... Resist pattern 5 ... Substrate, 6 ... Resist pattern, 7 ... Exposure region, 8 ...
Protective film 9 ... Eaves-like hardly soluble layer.

Claims (8)

[Claims] 1. A polymer obtained by protecting an alkali-soluble group of an alkali-soluble polymer with an acid labile group, (b) a compound which generates an acid upon irradiation with light, and (c) an imidazole compound. , Alanine compound, adenine compound, adenosine compound, quaternary ammonium salt compound, and nitrogen-containing saccharide compound, which is at least one compound selected from the group consisting of compounds that enhance compatibility in the resist film. Composition. 2. A polymer obtained by protecting an alkali-soluble group of an alkali-soluble polymer with an acid labile group, (b) a compound which generates an acid upon irradiation with light, (c) an imidazole compound, At least one compound selected from the group consisting of an alanine compound, an adenine compound, an adenosine compound, a quaternary ammonium salt compound, and a nitrogen-containing saccharide compound, which compound enhances compatibility in the resist film, and (d) phenol. A photosensitive composition containing a compound. 3. The photosensitive composition according to claim 2, wherein the phenol compound is at least one compound selected from the group consisting of triphenol compounds and polyvinylphenol. 4. The photosensitive composition according to claim 1, wherein the contained nitrogen saccharide compound is at least one of chitin and chitosan. 5. A step of forming a resin layer containing the photosensitive composition according to claim 1 as a main component on a substrate, a step of subjecting the resin layer to pattern exposure, a step of baking the resin layer after the exposure, And a pattern forming method comprising the step of developing the resin layer after baking using an alkaline solution as a developing solution. 6. A step of forming a resin layer containing the photosensitive composition according to claim 2 as a main component on a substrate, a step of subjecting the resin layer to pattern exposure, a step of baking the resin layer after the exposure, And a pattern forming method comprising the step of developing the resin layer after baking using an alkaline solution as a developing solution. 7. A step of forming a resin layer containing the photosensitive composition according to claim 3 as a main component on a substrate, a step of subjecting the resin layer to pattern exposure, a step of baking the resin layer after the exposure, And a pattern forming method comprising the step of developing the resin layer after baking using an alkaline solution as a developing solution. 8. A step of forming a resin layer containing the photosensitive composition according to claim 4 as a main component on a substrate, a step of subjecting the resin layer to pattern exposure, a step of baking the resin layer after the exposure, And a pattern forming method comprising the step of developing the resin layer after baking using an alkaline solution as a developing solution.