TWI620765B - Composition for forming resist underlayer film, underlayer film and pattern forming method - Google Patents

Abstract

An object of the present invention is to provide a dendrimer compound which can improve critical dimension uniformity and a focus depth margin, and a composition which can form a lower antireflection film.

The solution of the present invention is a dendrimer compound having an ether bond or a thioether bond at the end of a skeleton, a halogenated alkyl-substituted aromatic group and two or more OH groups, and a dendrimer compound A composition for forming an underlying antireflection film.

Description

Photoresist underlayer film forming composition, underlayer film, and pattern forming method

The present invention relates to a photoresist underlayer film forming composition for electron beam or extreme ultraviolet ray (EUV), which is used for component processing using extreme ultraviolet lithography, which can be reduced by electron beam or An adverse effect caused by extreme ultraviolet light, and a good photoresist pattern is effectively obtained; and a photoresist pattern forming method using the composition for forming a lower layer film for photoresist.

In the manufacturing process of a semiconductor device, fine processing is generally performed by using lithography of photoresist. The microfabrication means that a photoresist film is formed on a semiconductor substrate such as a germanium wafer, and an active light such as ultraviolet rays is irradiated thereon via a mask pattern on which an element pattern is drawn, and then developed, and the obtained photoresist is obtained. The pattern is used as a protective film to etch the substrate, thereby forming a processing method corresponding to the fine unevenness of the pattern on the surface of the substrate. In this technical field, in recent years, toward the highly integrated component, there is a tendency to KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), extreme ultraviolet light (EUV, wavelength 13.5 nm). Or an electron beam (EB; Electron beam) such a very short wavelength of light is used for exposure. However, in the photolithography step, "the influence of standing waves due to light reflection from the substrate may occur, or the height difference of the substrate may be caused. The problem of the diffuse reflection of the exposure light, which in turn reduces the dimensional accuracy of the photoresist pattern. Further, in the case where light having a very short wavelength such as extreme ultraviolet rays is used for exposure, the gas generated as the substrate of the base may adversely affect the photoresist layer. Therefore, in order to solve this problem, a method of providing a bottom anti-reflective coating between a photoresist and a substrate has been extensively studied. Such a lower anti-reflection film requires various characteristics. Specifically, it is preferable to have a characteristic that the radiation used for exposure to the photoresist has a large absorbance; the case of diffuse reflection or the like is small, and the cross-section of the photoresist after exposure and development is perpendicular to the surface of the substrate; The solvent contained in the photoresist composition is insoluble (not easily caused to cause intermixing) or the like. In particular, mutual mixing tends to affect the interface between the photoresist layer and the underlying anti-reflective film, thereby making the shape of the photoresist difficult to control.

In order to prevent the underlying antireflection film from being intermixed with the photoresist applied thereto, the underlying antireflection film is often formed using a thermally crosslinkable composition. As a result, the underlying antireflection film is formed, most of which is insoluble in the developer used in the general photoresist development process. Therefore, it is generally necessary to remove the lower anti-reflection film by dry etching before performing semiconductor substrate processing (for example, refer to Patent Document 1).

In recent years, it has been devoted to the study of ArF immersion lithography, which is exposed to water, as a next-generation photolithography technology after the use of ArF excimer laser (193 nm) photolithography. However, photolithography using light is facing the limit. As a new lithography technology after ArF immersion lithography, lithography using electron beams and extreme ultraviolet light (wavelength 13.5 nm) is attracting attention.

In the process of using electron beam or extreme ultraviolet lithography, due to the adverse effects caused by the base substrate, electron beam or extreme ultraviolet light, the following problems may occur: the photoresist pattern becomes a skirt and an undercut. The shape does not form a good rectangular photoresist pattern, the pattern sidewall roughness (line edge roughness) becomes large due to poor pattern shape, the critical dimension (CD; critical dimension) uniformity is deteriorated, and the photoresist pattern is The adhesion of the substrate is insufficient to cause pattern collapse, small focus depth margin, low sensitivity, and slow etching speed. Therefore, in the electron beam or extreme ultraviolet lithography process, an electron beam or an ultra-violet light lithography photoresist underlayer film which reduces such adverse effects and can form a good photoresist pattern is needed instead of the conventional one. Photoresist underlayer film (anti-reflective film) with reflective properties.

Further, as disclosed in Patent Documents 2, 3, and 4, the conventional underlayer film for electron beam or extreme ultraviolet lithography is mainly used as a polymer having a molecular weight distribution, and is considered to have a density change in the underlayer film. Big. Therefore, it cannot be said that the adverse effects caused by the base substrate or the electron beam and the extreme ultraviolet light are sufficiently improved.

Prior technical literature Patent literature

Patent Document 1 US Patent No. 6156479

Patent Document 2 Japanese Special Table 2008-501985

Patent Document 3 International Publication No. 2011/074494

Patent Document 4 International Publication No. 2012/017790

The present invention has been made in view of the above circumstances, and an object thereof is to provide a compound which can improve critical dimension uniformity, depth of focus margin, sensitivity, and etching speed in the case of using it in a lower antireflection film, and provides a composition An article that forms an antireflective film with improved properties.

The dendrimer compound of the present invention is characterized by the following formula (1): C(-Z) _m (-LA ¹ ) _4-m (1)

[In the formula (1), m is 0, 1, or 2; Z is a hydrocarbon group or a carboxyl group; when m is 2, each Z may be the same or different; and L is a hydrocarbon chain containing an ether bond or a thioether bond; L can be the same or different; A ¹ is

In the formula (1a), R ¹ is hydrogen or methyl; Y ¹ is oxygen or sulfur; B is,

(In the formula (1b), Y ² is oxygen or sulfur; Ar is an aromatic group substituted by a halogenated alkyl group); each B may be the same or different, and all of B in the formula (1) may be two or more. OH; p is an integer of 1 or more; each p may be the same or different}; at least two or more of A ¹ includes a group represented by the formula (1a)].

Further, the composition for forming a layer film of the present invention is characterized by comprising the dendrimer compound, a crosslinking agent, a thermal acid generator, and a solvent.

Further, the underlayer film of the present invention is characterized in that the underlayer film forming composition is applied onto a substrate and heated.

Furthermore, the pattern forming method of the present invention comprises the steps of: applying the composition for forming an underlayer film on a semiconductor substrate, and firing the film to form an underlayer film; and forming light on the underlayer film a step of exposing the semiconductor substrate covered by the underlayer film and the photoresist layer; and a step of developing with a developing solution after the exposing.

According to the present invention, it is possible to provide a novel dendrimer compound which can exhibit excellent characteristics in the case of use in a composition for forming an underlayer film. Further, in the embodiment of the present invention, the composition for forming a layer film is less likely to cause mutual mixing between the underlayer film and the photoresist composition layer at the time of pattern formation, and the cross section of the formed photoresist pattern can be obtained with respect to the base. The vertical photoresist pattern on the surface of the board improves the critical dimension uniformity, depth of focus margin, sensitivity and etch resistance.

Fig. 1 is a nuclear magnetic resonance (NMR) spectrum of a dendrimer compound of Example 1 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail below.

<dendrimer compound>

The dendrimer compound of the present invention is characterized by the following formula (1): C(-Z) _m (-LA ¹ ) _4-m (1)

[In the formula (1), m is 0, 1, or 2; Z is a hydrocarbon group or a carboxyl group; when m is 2, each Z may be the same or different; and L is a hydrocarbon chain containing an ether bond or a thioether bond; L can be the same or different; A ¹ is

In the formula (1a), R ¹ is hydrogen or methyl; Y ¹ is oxygen or sulfur; B is

(In the formula (1b), Y ² is oxygen or sulfur; Ar is an aromatic group substituted by a halogenated alkyl group); each B may be the same or different, and all of B in the formula (1) may be two or more. Is OH; p is an integer of 1 or more; each p may be the same or different}; at least 2 or more of A ¹ includes a group represented by the formula (1a)]

Further, in the formula (1), when m is not 0, it is generally referred to as a dendritic compound (Dendron compound), but the dendritic compound is included in the present invention, and is called a dendrimer compound. (Dendrimer compound).

In the formula (1), -LA ¹ and -Z are bonded to the central carbon, but two or more -LA ^{1 are required} . Therefore, although m can be 0, 1, or 2, when m is 2, the two Zs may be the same or different. Further, m is preferably 0, and 4 -LA ¹ is bonded to the central carbon to be a preferred aspect.

Z is any one of a hydrocarbon or a carboxyl group. In the case where it is a hydrocarbon, in order to maintain the shape of the formed photoresist pattern, the carbon number is preferably from 1 to 6, more preferably a methyl group or a carboxyl group.

In the formula (1), L is a hydrocarbon chain containing an ether bond (-O-) or a thioether bond (-S-). In other words, it is substituted with a hydrocarbon group of a methylene-CH ₂ - group by an ether bond or a thioether bond. Thus, the etching rate of the underlying film formed is improved by containing an ether bond or a thioether bond. When a hydrocarbon chain composed of only carbon and hydrogen is used, which does not contain an ether bond or a thioether bond, it is difficult to achieve a sufficient etching rate.

The ether bond and the thioether bond contained in L may be randomly disposed in the hydrocarbon chain or may be regularly disposed in the hydrocarbon chain. Further, the ether bond tends to improve the temporal stability of the composition as compared with the thioether bond. Therefore, relative The thioether bond contained in L is preferably a plurality of ether bonds; L does not contain a thioether bond but contains only an ether bond.

Typically, L is an alkylene oxide chain. In particular, from the viewpoint of easiness of production and the like, it is preferred to use an oxyethylene chain or an oxypropylene chain. The number of carbons contained in one L is not particularly limited, but for example, a carbon number of 2 to 6 can be used. Further, all of the L contained in the formula (1) is preferably an oxyalkylene chain.

In the formula (1), A is a terminal group B described below, or a group in which a terminal represented by the following formula (1a) is bonded with B,

(In the formula (1a), Y ¹ is oxygen or sulfur, and R ¹ is hydrogen or methyl)

The group represented by the formula (1a) contains a repeating unit, and since it branches at the terminal side, A can form a branched chain structure, and therefore, the compound of the formula (1) has a dendritic polymer structure. In the formula (1), the terminal group B may be directly bonded to the linking group L. However, when the compound represented by the formula (1) of the present invention is used for a composition for forming an underlayer film, in order to exhibit an excellent effect, it is necessary to have a group represented by the formula (1a) and have a branched chain structure. Therefore, at least two of the four L's of the formula (1) include a repeating unit represented by the formula (1a), that is, p is preferably 1 or more. At this time, in order to have sufficient film formability of the composition, p is preferably 2 or more. On the other hand, if the number of repetitions p is too large, the critical dimension uniformity or the depth of focus margin tends to deteriorate, so p is preferably 10 or less, more preferably 5 or less.

Although a plurality of p are included in the formula (1), each p may be the same or different.

Further, Y ¹ is either oxygen or sulfur, and each Y ¹ included in the formula (1) may be the same or different. However, from the viewpoint of ease of availability and safety, it is preferably oxygen, and it is preferred that each of Y ¹ contained in the formula (1) is oxygen. Further, R ¹ is any one of hydrogen or methyl, and each of R ¹ contained in the formula (1) may be the same or different, but all of R ¹ is preferably a methyl group.

The terminal group B is a hydroxyl group OH or a thiol group SH, or a group represented by the following formula (1b):

(In the formula (1b), Y ² is oxygen or sulfur, and Ar is an aromatic group substituted by a halogenated alkyl group).

Here, Ar is one which contains one or more benzene rings and contains an aromatic skeleton. Here, benzene, naphthalene, onion, biphenyl, benzimidazole or the like can be mentioned as an aromatic skeleton. In the dendrimer compound of the present invention, the aromatic skeleton is substituted with a halogenated alkyl group. The halogen constituting the halogenated alkyl group is preferably fluorine, chlorine, bromine or iodine, and is particularly preferably fluorine from the viewpoint of stability of the composition over time. The number of carbon atoms contained in the halogenated alkyl group is not particularly limited, but the carbon number is preferably 3 or less.

Ar may have a substituent other than a halogenated alkyl group. As such a substituent, for example, it is selected from an alkyl group, a hydroxyalkyl group, an aryl group, a halogen atom, an alkoxy group, a nitro group, an aldehyde group, a cyano group, an amine group, an alkylamino group, a dialkylamine. Base, sulfonamide, carboxyl, carboxylate, sulfonate Substituents for groups of sulfonic acid ester groups and aryl amine groups. Further, one of the benzene rings contained in the aromatic group may be substituted with an anthracene ring or may be condensed with a non-aromatic ring.

In the same manner as the polymer used for the composition for forming an underlayer film, the dendrimer compound of the present invention has a function of curing the composition by reacting with a crosslinking agent or the like. The dendrimer compound of the present invention contains at least two or more hydroxyl groups or thiol groups as a reactive group. That is, in the formula (1), at least two of all B are OH or SH, and preferably two or more are OH. Here, the higher the ratio of B contained in the formula (1) to OH or SH, the more the bonding due to the crosslinking reaction, the more preferable. Further, the more OH is compared with SH, the more the stability of the composition can be improved over time, and the like, the ratio of OH is preferably higher, and more preferably SH is not contained.

In the formula (1), the higher the proportion of the aromatic group-containing group represented by the formula (1b), the higher the film formability at the time of formation of the underlayer film. Therefore, it is necessary to appropriately adjust the ratio of the groups represented by OH, SH and the formula (1b) in B contained in the formula (1) in accordance with the purpose.

Specific examples of the dendrimer compound represented by the general formula (1) include the following.

(wherein, in all B ¹ , 50% is hydrogen and 50% is 4-(trifluoromethyl)benzylidene)

The compound represented by the general formula (1) can be produced by any method. For example, a compound represented by the following general formula (2), a compound represented by the following general formula (3), and a basic compound are obtained by reacting a compound represented by the general formula (2):

Wherein X is selected from the group consisting of chlorine, bromine and iodine; Y ² is oxygen or sulfur; Ar is an aromatic group substituted by a halogenated alkyl group; and the compound represented by the general formula (3): C (- Z) _m (-LA ² ) _4-m (3)

[In the formula (1), m is 0, 1 or 2; Z is a hydrocarbon group or a carboxyl group; when m is 2, each Z may be the same or different; [in the formula (3), m is 0, 1 or 2 Z is a hydrocarbon group or a carboxyl group; when m is 2, each Z may be the same or different; L is a hydrocarbon chain containing an ether bond or a thioether bond, and each L may be the same or different; A ² is

In the formula, R ¹ is hydrogen or methyl; Y ¹ is oxygen or sulfur; Z is independently oxygen or sulfur; and p is an integer independently selected from 1 or more.

Specific examples of the general formula (2) include 4-(trifluoromethyl)benzoguanidine chloride, 4-(trichloromethyl)benzhydrazide chloride, and 4-(tribromomethyl)benzamide. Chlorine, 4-(triiodomethyl)benzimidium chloride, 4-(trifluoromethyl)-1-naphthoquinone chloride, 4-(trifluoromethyl) onion-9-carbon chloride Wait.

Specific examples of the general formula (3) include the following products commercially available from Sigma-Aldrich Co., Ltd.: Hyperbranched bis-MPA polyester-16-hydroxyl generation 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.), Hyperbranched bis- MPA polyester-32-hydroxyl generation 3 (trade name, manufactured by Sigma-Aldrich Co., Ltd.), Polyester-16-hydroxyl-acetylene bis-MPA dendron generation 4 (trade name, manufactured by Sigma-Aldrich Co., Ltd.), Polyester-32-hydroxyl-acetylene bis-MPA dendron generation 5 (trade name, manufactured by Sigma-Aldrich Co., Ltd.), Polyester-16-hydroxyl-carboxyl bis-MPA dendron generation 4 (trade name, manufactured by Sigma-Aldrich Co., Ltd.), and the like.

The total amount of the compound represented by the general formula (2) is usually from 3 to 27 equivalents, preferably from 6 to 12 equivalents, per mole of the number of moles of the formula (3).

Examples of the basic compound include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide or barium hydroxide; alkali metal oxides such as sodium oxide or potassium oxide; An alkaline earth metal hydroxide such as magnesium hydroxide, calcium hydroxide, barium hydroxide or barium hydroxide; an alkaline earth metal oxide such as barium oxide, magnesium oxide, calcium oxide, barium oxide or barium oxide; methyl lithium, B Lithium, n-butyllithium, t-butyllithium, t-butyllithium, phenyllithium, lithium diisopropylamide or lithium hexamethyldisilazide Organic alkali metal; organic alkaline earth metal compound such as magnesium methoxide, diethyl magnesium, magnesium methyl chloride, magnesium bromochloride, magnesium bromide or magnesium bromide; sodium methoxide, sodium ethoxide, sodium propoxide or third An alkoxy compound such as potassium butoxide; a metal hydride such as sodium hydride, potassium hydride or calcium hydride; tetraalkylammonium hydroxide such as tetramethylammonium hydroxide or tetrabutylammonium hydroxide; lithium carbonate or carbonic acid An alkali metal carbonate compound such as sodium, potassium carbonate or calcium carbonate; Or an amine compound such as diethylamine, diethylamine or triethylamine; but in these examples, an amine compound such as ethylamine, diethylamine or triethylamine is preferred from the viewpoint of reactivity. Triethylamine. In addition, triethylamine can be purchased for use as a commercially available product. Relative to the general formula (2) The molar number of the compound to be represented, and the amount of the basic compound to be used is usually 3 to 27 equivalents, preferably 10 to 21 equivalents.

The reaction temperature at the time of reacting the respective components is preferably a certain amount or more in order to obtain a sufficient reaction rate, and is preferably a certain amount or less in order to suppress generation of unnecessary by-products. From this point of view, the reaction temperature is usually -50 to 150 ° C, preferably 20 to 100 ° C.

The reaction of the respective components may be carried out in the presence of a solvent or may be carried out without a solvent, but it is preferably carried out in the presence of a solvent from the viewpoint of improving the reaction yield and the ease of purification thereafter.

In the case of using a solvent, any solvent can be used as long as it does not adversely affect the reaction. Specifically, diethyl ether, third butyl methyl ether, tetrahydrofuran, and 1,4-two are preferred. Alkane, particularly preferably tetrahydrofuran. Further, from the viewpoint of the reaction rate and the reaction yield, the amount of the compound of the general formula (3) is usually 0.5 to 20 times, preferably 1 to 10 times, more preferably in terms of volume ratio. 1.5 to 5 times.

After the completion of the reaction, the target substance can be separated and purified from the reaction solution by a method generally used in organic synthesis. For example, in order to remove the basic compound, water may be sufficiently stirred, and the separated organic layer may be dried with a desiccant such as anhydrous magnesium sulfate, and then distilled under reduced pressure to obtain a target. Further, the reaction product can be purified by column chromatography in accordance with the demand.

<Under film forming composition>

The composition for forming a layer film of the present invention contains a crosslinking agent, a thermal acid generator, and a solvent in addition to the dendrimer compound. Moreover, depending on the demand, the composition contains other additives, for example Such as photoacid generator and surfactant. The components are described below.

Crosslinker

The composition for forming a layer film of the present invention contains a crosslinking agent. A crosslinking agent is used in order to prevent the underlayer film from being formed by mixing with the upper film such as a photoresist. Any compound can be used as the crosslinking agent as long as it is a compound which can act on the terminal hydroxyl group of the dendrimer compound at the time of exposure to form a crosslinked structure. Specific examples of such a crosslinking agent include hexamethyl melamine, hexamethoxymethyl melamine, 1,2-dihydroxy-N,N'-methoxymethylbutaneimine, 1,2. -dimethoxy-N,N'-methoxymethylbutaneimine, 1,3,4,6-fluorene (methoxymethyl)acetylene urea, tetramethoxymethylacetylene urea, N,N'-methoxymethylurea.

Hot acid generator

The composition for forming a layer film of the present invention contains a thermal acid generator. It is an adjuvant that promotes the formation of underlying film crosslinks. Specific examples of the thermal acid generator used in the composition for forming a layer film of the present invention include various aliphatic sulfonic acids and salts thereof; various aliphatic carboxylic acids such as citric acid, acetic acid, and maleic acid; a salt thereof; various aromatic carboxylic acids and salts thereof such as benzoic acid and phthalic acid; aromatic sulfonic acid and ammonium salts thereof; various amine salts; aromatic diazonium salts and phosphonic acids and salts thereof, and organic acids Salt or ester, etc. Particularly, in the thermal acid generator used in the present invention, a salt formed of an organic acid and an organic base is preferred, and a salt formed from a sulfonic acid and an organic base is more preferred.

Preferred examples of the thermal acid generator containing a sulfonic acid include p-toluenesulfonic acid, benzenesulfonic acid, p-dodecylbenzenesulfonic acid, 1,4-naphthalenedisulfonic acid, methanesulfonic acid and the like. These acid generators may be used singly or in combination.

Solvent

The solvent to be used as the composition for forming a layer film of the present invention may be any solvent as long as it is a solvent capable of dissolving the above components. Specific examples of the solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, acesulfame acetate, ethyl acesulfame acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, 2-hydroxyl Methyl 2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, 3-methoxy Ethyl propionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate , N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone. These solvents may be used singly or in combination of two or more. Further, a high boiling point solvent such as propylene glycol monobutyl ether or propylene glycol monobutyl ether acetate may be used in combination.

Photoacid generator

The composition for forming an antireflection film of the present invention contains a photoacid generator as required. Mostly used to remove the upper film, that is, the scum of the photoresist and the footing.

Such a photoacid generator can be arbitrarily selected from those well known in the art. Specific examples of the photoacid generator include an onium salt compound, a crosslinkable onium salt compound, a sulfomadamine derivative, and a disulfonyldiazomethane compound.

Specific examples of the onium salt compound include diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, and Phenyl iodide perfluoro-n-octane sulfonate, diphenyl iodonium sulfonate, bis(4-t-butylphenyl) camphorsulfonate and bis(4-tert-butyl Anthracene salt compound such as phenyl) fluorene trifluoromethanesulfonate; and triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-n-butane sulfonate, triphenyl camphorsulfonate and triphenyl a phosphonium salt compound such as trifluoromethanesulfonate; and bis(4-hydroxyphenyl)(phenyl)phosphonium trifluoromethanesulfonate, bis(4-hydroxyphenyl)(phenyl)phosphonium-1, 1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate, phenylbis(4-(2-(vinyloxy)ethoxy)phenyl)anthracene- 1,1,2,2,3,3,4,4-octafluorobutane-1,4-disulfonate, ginseng (4-(2-(vinyloxy)ethoxy)phenyl)anthracene a crosslinkable onium salt compound such as -1,1,2,2,3,3,4,4-octafluorobutane-1,4-disulfonate, but is not limited thereto.

Specific examples of the sulfomaleimide derivative include, for example, N-(trifluoromethanesulfonyloxy)butaneimine, N-(nonafluoro-n-butanesulfonyloxy)butyl Diimine, N-(camphorsulfonyloxy)butaneimine, and N-(trifluoromethanesulfonyloxy)naphthylimine.

Specific examples of the disulfonyldiazomethane compound include bis(trifluoromethanesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, and bis(phenylsulfonyl). Diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, and methanesulfonyl-p-toluenesulfonyldiazomethane. In the composition for forming an antireflection film of the lower layer of the present invention, these photoacid generators may be used in combination of two or more kinds.

Other ingredients

The composition for forming an antireflection film of the lower layer of the present invention may contain other components as needed. For example, a surfactant, a smoothing agent, etc. are mentioned. Those who do not impair the effects of the present invention should be used as such components.

The following examples are intended to further illustrate the invention. The invention is not limited to the embodiments. Further, in the present specification, the "parts" in the examples mean "parts by weight" and "%" means "% by weight" unless otherwise specified.

Example 1

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl)benzhydrin chloride (477 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, methyl tertiary butyl ether (hereinafter also referred to as MTBE) (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 74%. The modification rate of 4-(trifluoromethyl)benzhydryl chloride was 49.9%.

The ¹ H-NMR spectrum (solvent: dimethyl azine) of the obtained dendrimer is shown in FIG.

Example 2

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated to reflux, 4-(trichloromethyl)benzhydrin chloride (590 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 72%. The modification rate of 4-(trichloromethyl)benzhydryl chloride was 49.7%.

Example 3

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(tribromomethyl)benzhydrin chloride (894 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 69%. The modification rate of 4-(tribromomethyl)benzimid chloride was 50.5%.

Example 4

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated to reflux, 4-(triiodomethyl)benzhydrin chloride (1217 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 65%. The modification rate of 4-(triiodomethyl)benzhydryl chloride was 49.6%.

Example 5

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen inlet pipe, and a temperature control device, it is added under a nitrogen atmosphere. Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl)-1-naphthoquinone chloride (591 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 74%. The modification rate of 4-(trifluoromethyl)-1-naphthoquinone chloride was 49.9%.

Example 6

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl) onion-9-carbonium chloride (706 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. After that, filtration is carried out, and the MTBE solution is concentrated by distillation under reduced pressure, thereby producing The rate of 77% gave the target dendrimer compound. The modification rate of 4-(trifluoromethyl) onion-9-carbon ruthenium chloride was 48.9%.

Example 7

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-32-hydroxyl genaration 3 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (1031 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl)benzhydrin chloride (477 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer compound was obtained in a yield of 79%. The modification rate of 4-(trifluoromethyl)benzhydryl chloride was 50.0%.

Example 8

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl)benzhydrin chloride (119 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer was obtained in a yield of 43%. The modification rate of 4-(trifluoromethyl)benzhydryl chloride was 12.5%.

Example 9

In a reactor equipped with a stirrer, a condenser, a heating device, a nitrogen gas introduction tube, and a temperature control device, Hyperbranched bis-MPA polyester-16-hydroxyl genaration 2 (trade name, manufactured by Sigma-Aldrich Co., Ltd.) was added under a nitrogen atmosphere. (500 parts), triethylamine (231 parts), and dehydrated tetrahydrofuran (2000 parts) were stirred. After the reaction mixture was heated under reflux, 4-(trifluoromethyl)benzhydrin chloride (834 parts) was slowly added. After the end of the addition, the mixture was heated to reflux for 2 hours.

After cooling to room temperature, MTBE (30000 parts), pure water (30000 parts) was added, and the MTBE solution was extracted. Further, saturated sodium hydrogencarbonate water (30000 parts) was added to the MTBE solution, and the MTBE solution was extracted. Next, magnesium sulfate (200 parts) was added to the MTBE solution and stirred. Thereafter, filtration was carried out, and the MTBE solution was concentrated by distillation under reduced pressure, whereby the desired dendrimer was obtained in a yield of 94%. The modification rate of 4-(trifluoromethyl)benzhydryl chloride was 87.5%.

Comparative example 1

In the reactor equipped with a stirrer, condenser, heating device and temperature control device, 1,3,4,6-fluorene (methoxymethyl)acetylene was added. Urea (manufactured by Sanwa Chemical Co., Ltd., MX-270 (trade name)) (84.20 parts), 2,5-dimethylphenol (8.42 parts), 3-iodophenol (29.19 parts), and the solution is heated To 80 ° C. After the solution temperature reached 80 ° C, p-toluenesulfonic acid monohydrate (0.8420 parts) was added. After the end of the supply, the reaction mixture was maintained at 80 ° C for 5 hours.

After cooling to room temperature, the reaction solution was poured into pure water (6000 parts), and the precipitate was filtered. Next, the precipitate was dissolved in 150 g of acetone, and poured into pure water (3000 parts), and the precipitate was filtered. The polymer was obtained in a yield of 39% by drying the precipitate under vacuum at 50 °C. The molecular weight was measured by a gel permeation chromatography (GPC) (tetrahydrofuran (THF)), and as a result, a weight average molecular weight Mw = 3046 Da, a number average molecular weight Mn = 1263 Da, and a polydispersity index PDI = 2.41 were obtained.

Application Example 1

The fluorine-containing ether dendrimer of Example 1 (1.26 parts); 1,3,4,6-fluorene (methoxymethyl)acetylene urea (1.26 parts) as a crosslinking agent (Sanhe Chemical Co., Ltd.) Company, MX-270 (trade name)); 10-camphorsulfonic acid (0.0173 parts) as a thermal acid generator; triethylamine (0.008 parts) as a thermal acid generator; triphenyl as a photoacid generator Base salt (hereinafter referred to as TPS) (0.0252 parts); propylene glycol monomethyl ether acetate (136.162 parts) as a solvent was mixed, and stirred at room temperature for 30 minutes to prepare a composition for forming an underlayer film.

The composition for forming a film for forming a lower layer was applied onto a microchip wafer by spin coating, and heated at 200 ° C for 60 seconds using a vacuum heating plate to carry out a crosslinking reaction to obtain an underlayer film.

Application Examples 2 to 10 and Application Comparison Examples 1 to 2

The compositions of Examples 2 to 10 and Comparative Examples 1 to 2 were applied in the same manner as in Application Example 1, except that the respective components of the underlayer film composition were changed as shown in Table 1.

The prepared composition was evaluated as follows.

Optical characteristics evaluation:

The underlayer film was measured by an elliptical spectral polarimeter VUV-302 (trade name, manufactured by J.A. Woollam Co., Ltd.). For example, in Application Example 1, the attenuation coefficient (k value) at a wavelength of 193 nm is 0.3504; and the attenuation coefficient (k value) at 248 nm is 0.0204.

Solvent resistance evaluation:

The film thickness reduction test of the underlayer film was carried out with ethyl lactate, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. The evaluation criteria are as follows.

A: The underlayer film is insoluble in any one of ethyl lactate, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether, and is a grade having excellent practicability.

B: Although it was confirmed that the underlayer film was slightly dissolved in any of ethyl lactate, propylene glycol monomethyl ether acetate or propylene glycol monomethyl ether, it was a practically no problem.

C: The lower film is soluble in any or all of ethyl lactate, propylene glycol monomethyl ether acetate or propylene glycol monomethyl ether, and is not of a practical grade.

Evaluation of density changes:

The density of the underlayer film was measured by an X-ray reflectance apparatus (trade name, manufactured by Rigaku Co., Ltd.) by an X-ray reflectance measuring method, and the density of the underlayer film was measured, and the density change was evaluated. For example, in Application Example 1, the density near the surface is 1.52 g/cm ³ , the density of the intermediate portion is 1.44 g/cm ³ , and the density near the bottom surface is 1.47 g/cm ³ , and the standard deviation of the measured values (sigma). The value (change value) is 0.04.

Evaluation of dry etching speed ratio:

The dry etching rate of the underlayer film was measured under the conditions of using oxygen as a dry etching gas using RIE SYSTEM ES401 (trade name, manufactured by Nippon Scientific Co., Ltd.). Further, a photoresist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: SEVR-162) was applied onto a tantalum wafer using a spinner to form a photoresist film. Next, using RIE SYSTEM ES401 (trade name, manufactured by Nippon Scientific Co., Ltd.), the dry etching rate was measured under the condition that oxygen gas was used as the dry etching gas. A comparison was made between the underlayer film and the dry etching rate of the photoresist film obtained from the photoresist solution manufactured by Sumitomo Chemical Co., Ltd. For example, in the case of Application Example 1, the ratio of the dry etching rate of the photoresist underlayer film to the dry etching rate of the photoresist film was calculated and found to be 1.81.

Extreme ultraviolet exposure test

The resist underlayer film forming composition solution prepared by applying Example 1 of the present invention was spin-coated on a tantalum wafer and heated at 200 ° C for 1 minute to form a photoresist underlayer film. A photoresist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: SEVR-162) was spin-coated on the underlayer film of the photoresist and heated, using an extreme ultraviolet light exposure apparatus (Albany MET) at NA = 0.36, σ Exposure was carried out under conditions of 0.93. After the exposure, the film was heated after exposure, cooled to room temperature with a cooling plate, and subjected to development and rinsing treatment to form a photoresist pattern on the ruthenium wafer.

Electron beam exposure test

The photoresist underlayer film forming composition solution prepared in Application Example 1 of the present invention was spin-coated on a ruthenium wafer, and heated at 200 ° C for 1 minute to form a photoresist underlayer film. The electron beam resist solution was spin-coated on the underlayer film of the photoresist and heated, and exposure was performed using an electron beam exposure apparatus. After the exposure, the post-exposure heating is performed, the cooling plate is cooled to room temperature, and development and rinsing are performed to form a photoresist pattern on the ruthenium wafer. The sensitivity, depth of focus, and critical dimension uniformity (CDU) were evaluated in the same manner as the extreme ultraviolet exposure test.

Evaluation of pattern section shape

Observation was performed by an electron microscope, and evaluation was performed based on the following criteria.

A: a rectangular shape in which the side of the photoresist is perpendicular to the surface of the substrate

B: The side surface of the photoresist is not perpendicular to the surface of the substrate, and although it is slightly inclined, it is a level that is practically no problem.

C: the side of the photoresist is a footing shape with respect to the surface of the substrate

Evaluation of sensitivity (unit: mJ/cm ² ):

The exposure amount (mJ/cm ² ) of the one-to-one contact hole having a width of 30 nm was formed as the optimum exposure amount by the width of the photomask formed by the one-to-one contact hole having a size of 30 nm, and the exposure amount (mJ) was obtained. /cm ² ) as "sensitivity".

Evaluation of depth of focus (DOF) (unit: μm):

At the optimum exposure amount, the pattern size of the mask pattern of the one-to-one contact hole of 30 nm is taken as the depth of focus (DOF) when the pattern size of the mask is within ±10% of the design size of the mask.

Evaluation of critical dimension uniformity (CDU) (unit: nm):

When a 30-nm one-to-one contact hole which is analyzed by the optimum exposure amount is observed from above the pattern, the pattern width is measured at 100 points at an arbitrary point, and the three-sigma value of the measured value is changed. Value) as critical dimension uniformity (CDU).

The results obtained are shown in Tables 1 and 2.

Claims (11)

A composition for forming an underlayer film, comprising: a dendrimer compound, a crosslinking agent, a thermal acid generator, and a solvent; and the dendrimer compound is a compound represented by the following formula (1) :C(-Z) _m (-LA ¹ ) _4-m (1) [In the formula (1), m is 0, 1 or 2; Z is a hydrocarbon group or a carboxyl group; when m is 2, each Z may be the same It may be different; L is a hydrocarbon chain containing an ether bond or a thioether bond; each L may be the same or different; A ¹ is B or In the formula (1a), R ¹ is hydrogen or methyl; Y ¹ is oxygen or sulfur; B is OH, SH, or (In the formula (1b), Y ² is oxygen or sulfur; Ar is an aromatic group substituted by a halogenated alkyl group); each B may be the same or different, and all of B in the formula (1) may be two or more. OH; p is an integer of 1 or more, and each p may be the same or different}; at least two or more of A ¹ includes a group represented by the formula (1a)]. A composition for forming a film under the item 1, wherein m is 0. The composition for forming a film under the item 1 or 2, wherein all of the L in the formula (1) is an alkylene oxide chain. A composition for forming a film under the item 1 or 2, wherein all of R ¹ in the formula (1) is a methyl group. The composition for forming a film under the item 1 or 2, wherein the halogenated alkyl group has a carbon number of 3 or less. A composition for forming a film under the item 1 or 2, wherein the B is not SH. A composition for forming a film under the item 1 or 2, wherein all of Y ¹ in the formula (1) is oxygen. A composition for forming a film under the item 1, which further comprises a photoacid generator. An underlayer film which is formed by applying a composition for forming a layer film according to any one of claims 1 to 8 onto a substrate and heating it. A method of forming a pattern, comprising the steps of: coating a composition for forming a layer film according to any one of claims 1 to 8 on a semiconductor substrate, and firing to form an underlayer film; a step of forming a photoresist layer on the underlayer film; a step of exposing the semiconductor substrate covered by the underlayer film and the photoresist layer; and a step of developing with a developer after the exposing. The pattern forming method of claim 10, wherein the exposing is performed by light having a wavelength from an electron beam to a KrF excimer laser.