TWI462960B - Resist underlayer film forming composition and method for forming resist pattern by use of said composition - Google Patents

Description

Photoresist underlayer film forming composition and method for forming photoresist pattern using the same

The present invention relates to a photoresist pattern forming composition for lithography which is useful for processing a semiconductor substrate, and a photoresist pattern forming method for forming a composition using the photoresist underlayer film. Further, when the photoresist film is exposed, the photoresist underlayer film which suppresses the influence of the reflected wave on the photoresist film may also be referred to as an antireflection film.

From the manufacture of conventional semiconductor devices, microfabrication using lithography using a photoresist composition has been performed. The microfabrication process is performed by forming a thin film of a photoresist composition on a semiconductor substrate such as a germanium wafer, and irradiating the active light such as ultraviolet rays through a mask pattern in which a device is drawn, and performing development. The obtained photoresist pattern is used as a protective film to etch the substrate, and a processing method for forming fine irregularities of the above-described pattern is formed on the surface of the substrate. In recent years, with the high integration of semiconductor devices, the active light used is also short-wavelength from i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm) to ArF excimer laser (wavelength 193 nm). .

However, in order to prevent the photoresist pattern from collapsing or the like, it is desired to reduce the thickness of the photoresist layer, and to suppress the decrease in the film thickness of the photoresist layer in the etching removal step. As the photoresist underlayer film to be used together, a photoresist underlayer film which can be removed by etching in a shorter time is desired. In order to shorten the etching removal step, it is required to reduce the film of the photoresist solvent to be small, to use a photoresist under the thin film, or to have a higher etching speed selectivity with the photoresist. The photoresist underlayer film. In addition, in order to cope with the related requirements, various photoresist underlayer film forming compositions or antireflection films have been proposed (for example, Patent Document 1 to Patent Document 3).

Further, in the conventional composition for forming a photoresist film, a stronger cured film can be formed by heat crosslinking, and in addition to a polymer which is a matrix of the cured film, a crosslinking agent and a crosslinking agent are usually blended. catalyst. Further, in recent years, in order to improve the edge shape of the photoresist pattern, there are also acidic additives and the like.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 03/017002

[Patent Document 2] JP-A-2004-212907

[Patent Document 3] JP-A-2005-049810

The photoresist underlayer film is required to have a larger dry etch rate than the photoresist film (the selection ratio of the dry etch rate is large). However, a conventional photoresist underlayer film (antireflection film or the like) formed of a composition containing an acrylic resin or a methacrylic resin is not necessarily satisfactory in terms of dry etching rate. The reason for this is considered to be due to the bonding of the carbon atoms constituting the main chain of the acrylic resin or the methacrylic resin (C-C bonding), which is not easily broken by dry etching.

Further, in recent years, in the lithography process for manufacturing a semiconductor device, when the photoresist underlayer film is formed using the conventional photoresist underlayer film forming composition, it is derived from the low amount of the crosslinking agent or the acidic additive at the time of firing. The occurrence of sublimates of molecular compounds has gradually become a new problem. The sublimate is thereafter attached to the underlying film of the photoresist, for example, as a foreign matter, and it is desired to impart adverse effects such as defects, and it is required to satisfy a new one which can suppress the occurrence of such a sublimate as much as possible. Proposal for the composition of performance requirements.

The present invention has been made in view of the above circumstances, and provides a performance requirement of a photoresist underlayer film which is larger than a dry etching rate, and suppresses the occurrence of a sublimate at the time of film formation (at the time of firing). The novel underlayer film forming composition and the photoresist pattern forming method using the underlayer film forming composition.

The present invention contains a benzaldehyde derivative having an aromatic carbonyl derivative such as an aromatic aldehyde derivative or an aromatic ketone derivative, preferably one or two selected from the group consisting of a hydroxyl group and a carboxyl group and having at least two substituents. Or a naphthaldehyde derivative, a polymer obtained by reacting a diepoxy compound having two epoxy groups, a sulfonic acid compound, and a solvent for a lithographic photoresist underlayer film to form a composition. The polymer has an aromatic carbonyl structure in the main chain, for example, an aromatic aldehyde structure, and the aromatic aldehyde structure is preferably a secondary polymer or a linear polymer of a benzaldehyde structure or a naphthaldehyde structure; the aforementioned aromatic carbonyl structure Introduced into the polymer by ether linkage, ie, -COC-, or ester linkage, ie, -C(=O)-O- or -OC(=O)-, or ester linkage and ether linkage. Main chain. The polymers in the present invention are referred to as non-monomer polymers and do not exclude so-called oligomers.

The polymer contained in the composition of the present invention has the following formula (1):

(wherein R, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ and A ₆ each independently represent a hydrogen atom, a methyl group or an ethyl group, Q represents a divalent organic group, and n ₁ represents a 1 to 4 The number, n ₂ and n ₃ each independently represent the number of 0 or 1, and m represents the repeating structure represented by the number of repeating units, which is 5 to 300).

The number m of repeating units is, for example, 10 or more and 300 or less.

Further, the polymer may contain a structure other than the above formula (1). The main repeating structure represented by the above formula (1) and any structures contained therein are arranged in a line to constitute a polymer.

The repeating structure represented by the above formula (1) is, for example, an R-based hydrogen atom and has an aromatic aldehyde structure in the main chain, and more preferably a structure represented by the following formula (1a).

(wherein A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ , Q and m are as defined in the above formula (1)).

Alternatively, the polymer contained in the composition of the present invention contains the following formulas (2) and (3):

(In the formula (2), R represents a hydrogen atom, a methyl group or an ethyl group, n ₁ represents a number from 1 to 4, and n ₂ and n ₃ each independently represent a number of 0 or 1.

In the formula (3), two kinds of structures represented by A ₁ , A ₂ , A ₃ , A ₄ , A ₅ and A ₆ each independently represent a hydrogen atom, a methyl group or an ethyl group, and Q represents a divalent organic group) The polymer of the unit.

Further, the polymer may contain structural units other than the above formula (2) and formula (3). The main structural unit represented by the above formulas (2) and (3) and the arbitrarily contained structural unit are linearly arranged to constitute a polymer.

The structural unit represented by the above formula (2) is more preferably a structural unit represented by the following formula (2a).

In the above formula (1), formula (1a) or formula (3), Q is the following formula (4):

(wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a phenylene group, an anthranyl group or a fluorenyl group; The phenyl group, the extended naphthyl group and the fluorenyl group are respectively selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon atom number of 1. Substituting at least one group of groups of alkylthio groups to 6 and n ₄ and n ₅ each independently represent a group represented by number 0 or 1.

Further, in the above formula (1), formula (1a) or formula (3), Q is a formula (5):

[wherein, X ₁ is the following formula (6) or the following formula (7):

(wherein R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from a carbon atom. Substituting at least one group of a group of 1 to 6 alkyl groups, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms, or R ₁ and R ₂ are bonded to each other to form a ring having a carbon number of 3 to 6 or a divalent group represented by the group.

In the repeating structure represented by the above formula (1), the repeating structure represented by the above formula (1a), or the structural unit represented by the above formula (3), Q is in addition to the group represented by the above formula (5), and Q is further It may also contain a group represented by the above formula (4).

Or in the above formula (1), formula (1a) or formula (3), Q is the following formula (8):

(wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and at least one group in which an alkylthio group having 1 to 6 carbon atoms is substituted.

In the repeating structure represented by the above formula (1), the repeating structure represented by the above formula (1a), or the structural unit represented by the formula (3), Q is in addition to the group represented by the above formula (8), Q is further It may also contain a group represented by the above formula (4).

In the present invention, the alkyl group may be limited to a linear form or a branched form, and examples thereof include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and an n-hexyl group. The alkylene group may, for example, be a methyl group, an ethyl group, an n-propyl group, an n-amyl group, an n-exenyl group, a 2-methyl-propyl group, or a 1,4-dimethyl group. base. The alicyclic hydrocarbon may, for example, be cyclobutane, cyclohexane or adamantane. The alkoxy group may, for example, be a methoxy group, an ethoxy group, an n-pentyloxy group or an isopropoxy group. The alkylthio group may, for example, be a methylthio group, an ethylthio group, an n-pentylthio group or an isopropylthio group. The alkenyl group may, for example, be a vinyl group, a 1-propenyl group, a 2-propenyl (allyl) group, a 1-methyl-2-propenyl group, a 1-butenyl group, a 2-butenyl group or a 3-butene group. base. The alkylene group, the alkoxy group and the alkylthio group are not limited to a linear chain, and may be a branched structure or a cyclic structure. The halogen atom may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

The polymer having the repeating structure represented by the above formula (1) or the polymer containing the two structural units represented by the formulas (2) and (3) is at least one compound represented by the following formula (9). And at least one compound represented by the following formula (10):

(wherein R represents a hydrogen atom, a methyl group or an ethyl group, n ₁ represents a number from 1 to 4, and n ₂ and n ₃ each independently represent a number of 0 or 1, A ₁ , A ₂ , A ₃ , A ₄ , A reaction product in which A ₅ and A ₆ each independently represent a hydrogen atom, a methyl group or an ethyl group, and Q represents a divalent organic group.

In other words, at least one compound represented by the formula (9) and at least one compound represented by the formula (10) are appropriately molar ratios, and dissolved in an organic solvent to dissolve the epoxy group. A polymer having a repeating structure represented by the above formula (1) or a polymer containing two structures represented by the formulas (2) and (3) can be obtained by polymerization in the presence of a catalytic catalyst. Here, the compounds represented by the formulae (9) and (10) may be used alone or in combination of two or more kinds of compounds. Further, the ratio of the compound represented by the formula (9) used in the reaction to the compound represented by the formula (10) is 3:1 to 1:3 in terms of molar ratio, and the formula (9): formula (10). Preferably, it is 3:2~2:3 or 5:4~4:5, and the best is 1:1.

The catalyst for activating the epoxy group means, for example, a fourth-order phosphonium salt such as ethyltriphenylphosphonium bromide or a fourth-order ammonium salt such as benzyltriethylammonium chloride, relative to the use thereof. The total mass of the compound represented by the formula (9) and the compound represented by the formula (10) can be selected from an appropriate amount in the range of 0.1 to 10% by mass.

The temperature and time of the polymerization reaction can be selected from 80 to 160 ° C for 2 to 50 hours.

Suitable examples of the compound represented by the above formula (9) include 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, and 3,4-dihydroxybenzaldehyde. And 3,5-dihydroxybenzaldehyde or the like, particularly preferably 2,4-dihydroxybenzaldehyde.

In the above formula (10), Q is the following formula (11):

(wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a phenylene group, an anthranyl group or a fluorenyl group, the aforementioned The phenyl group, the extended naphthyl group and the fluorenyl group are respectively selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon atom number of 1. Substituting at least one group of groups of alkylthio groups to 6 and n ₄ and n ₅ each independently represent a group represented by number 0 or 1.

The compound represented by the above formula (10) is, for example, the following formula (13):

(wherein, Y represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group or an alkylthio group having 1 to 6 carbon atoms, and p represents 0. To an integer of 4, when p is 2 to 4, the above Y may be the same or different).

Further, in the above formula (10), Q is a following formula (12):

(wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms in a group substituted by 1 group).

The compound represented by the above formula (10) is preferably a symmetrical structure having a holding structure Q, and specific examples thereof are represented by the following formulas (10-a) to (10-i), but are not limited thereto.

Further, in addition to the compounds represented by the above formulas (9) and (10), the polymer of the present invention can also be reacted as another compound having a polymerizable group, without impairing the effects of the present invention. The resulting reaction product.

In particular, it is possible to suppress the k value at a specific wavelength by adding another compound which imparts a functional group for absorption at a specific wavelength. For example, a compound having a unit for imparting absorption at a wavelength of 193 nm may be 2,4-dihydroxybenzoic acid or the like.

The sulfonic acid compound contained in the composition of the present invention is used as a compound for promoting the crosslinking reaction, and may be added in an amount of, for example, 0.1% by mass or more and 10% by mass or less based on the polymer contained in the composition of the present invention. Specific examples of the sulfonic acid compound include p-phenolsulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridine p-toluenesulfonate, camphorsulfonic acid, 5-sulfuric acid, and 4-chlorobenzenesulfonic acid. , 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid and 1-naphthalenesulfonic acid.

The solvent contained in the composition of the present invention is, for example, selected from the group consisting of propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monopropyl ether, methyl ethyl ketone, ethyl lactate, A solvent in which a mixture of cyclohexanone, γ-butyrolactone, and N-methyl-2-pyrrolidone is contained, or a mixture of two or more solvents. Further, the solvent ratio is, for example, 50% by mass or more and 99.5% by mass or less based on the composition of the present invention.

The ratio of the polymer contained in the composition of the present invention is, for example, 0.5% by mass or more and 30% by mass or less based on the photoresist underlayer film forming composition.

The composition of the present invention may contain a crosslinkable compound (crosslinking agent) in addition to the polymer, the sulfonic acid compound and the solvent, and may further contain a crosslinking other than the sulfonic acid compound. The compound of the reaction.

When the solvent-removing component is defined as a solid component, the solid component contains an additive such as a polymer and a crosslinkable compound added as necessary, and a compound which promotes a crosslinking reaction. The ratio of the polymer in the solid content is, for example, 70% by mass or more and 98% by mass or less.

The crosslinkable compound, for example, has 2 to 4 nitrogen-containing compounds having a nitrogen atom substituted by a methylol group or an alkoxymethyl group, and may be, for example, 1% by mass or more based on the polymer contained in the composition of the present invention. The ratio of the mass% or less is added. Specific examples of the crosslinkable compound include hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine, 1,3,4,6-fluorene (methoxymethyl)acetylene urea, and 1,3. , 4,6-fluorene (butoxymethyl)acetylene urea, 1,3,4,6-fluorene (hydroxymethyl)acetylene urea, 1,3-bis(hydroxymethyl)urea, 1,1,3 , 3-indole (butoxymethyl) urea and 1,1,3,3-indole (methoxymethyl) urea, and the like.

The compositions of the present invention may also contain a surfactant and/or a co-agent. The surfactant is an additive for improving the coatability of the substrate. A known surfactant such as a nonionic surfactant or a fluorine-based surfactant can be used, and the composition of the present invention can be added in a ratio of, for example, 0.01% by mass or more and 0.5% by mass or less. Next, the auxiliary agent is an additive for suppressing peeling of the photoresist film at the time of development after exposure for the purpose of improving the adhesion between the substrate or the photoresist film and the photoresist underlayer film. Further, for example, a chlorosilane, an alkoxy decane, a decane, a decane or a heterocyclic compound can be used as the auxiliary agent, and the composition can be formed, for example, at 0.1% by mass or more, based on the photoresist underlayer film forming composition of the present invention. Add the percentage below %.

The composition of the present invention is applicable to the lithography step in the manufacturing process of a semiconductor device. a step of forming a photoresist underlayer film by coating the composition of the present invention on a semiconductor substrate and baking, forming a photoresist film on the photoresist underlayer film, and passing the photoresist underlayer film and the light The step of exposing the semiconductor substrate covered by the resist film, and the step of developing the photoresist film after exposure to form a photoresist pattern.

The above exposure is performed, for example, using an ArF excimer laser. EUV (wavelength 13.5 nm) or electron lines can also be used in place of ArF excimer lasers. "EUV" is an abbreviation for extreme ultraviolet light. The photoresist for forming the photoresist film may be either a positive type or a negative type. Chemically amplified photoresists that are sensitive to ArF excimer lasers, EUV or electron lines can be used.

A representative of the semiconductor substrate is a germanium wafer, and an SOI (Silicon on Insulator) substrate or a compound semiconductor wafer such as gallium antimonide (GaAs), indium phosphide (InP), or gallium phosphide (GaP) may be used. A semiconductor substrate on which an insulating film such as a hafnium oxide film, a nitrogen-containing hafnium oxide film (SiON film), or a carbon-containing hafnium oxide film (SiOC film) is formed may be used. In this case, the present invention is coated on the insulating film. Composition.

The photoresist underlayer film forming composition of the present invention is not an essential component for use as a crosslinking agent which is widely used in conventional photoresist underlayer film forming compositions, and an acidic additive for improving the shape of a photoresist pattern. Therefore, when the photoresist underlayer film forming composition is applied onto a substrate and baked to form an underlayer film, generation of a sublimate derived from a component such as a crosslinking agent can be suppressed, and thereafter, the layer caused by the photoresist can be suppressed. Defects caused by sublimation attached to a film or the like occur.

Further, the photoresist underlayer film forming composition of the present invention contains a polymer having an aromatic carbonyl structure in the main chain, for example, an aromatic aldehyde structure. The aromatic carbonyl structure includes, for example, a polymer having a repeating structure represented by the above formula (1) or a polymer containing two structural units represented by the above formulas (2) and (3). Therefore, it is possible to obtain a photoresist underlayer film which does not lower the density of the aromatic ring and has a large selection ratio of the dry etching rate of the photoresist film. Moreover, the main chain of the secondary polymer (linear polymer) contained in the photoresist underlayer film forming composition of the present invention is more susceptible to CO bonding (dry bond bonding) by dry etching than CC bonding. The ether bond) can increase the dry etching rate of the obtained photoresist underlayer film compared to the composition for forming a photoresist underlayer film using an acrylic resin or a methacrylic resin as a polymer. Therefore, the time required for the removal of the photoresist for the dry etching of the underlayer film can be shortened, and the reduction in the film thickness of the photoresist layer caused by the removal required for the dry etching of the underlayer film can be suppressed.

Further, the lithographic underlayer film forming composition of the present invention can form light for short wavelengths, particularly for KrF excimer laser (wavelength 248 nm) and/or ArF excimer laser (wavelength 193 nm). The light resists the underlying film. Therefore, the obtained photoresist lower layer film can efficiently absorb the reflected light from the substrate, and can also be used as an effective absorption from the semiconductor substrate in the lithography step using a KrF excimer laser or an ArF excimer laser. The film of the antireflection film that reflects light, that is, the photoresist underlayer film having a practical refractive index and attenuation coefficient among the above wavelengths.

Further, the polymer of the photoresist underlayer film forming composition of the present invention is introduced into an aromatic carbonyl derivative having a benzene ring or a naphthalene ring as an aromatic ring, for example, an aromatic group, as described above. An aldehyde derivative or an aromatic ketone derivative can increase the density of the formed underlying photoresist film, and can have a desired shape (a rectangular shape in a cross section perpendicular to the substrate), and a sleeve-free photoresist Graphic type.

Hereinafter, the invention will be described in detail with reference to the examples, but the invention is not limited by the examples.

The weight average molecular weight shown in the following synthesis examples of the present specification is a measurement result obtained by gel permeation chromatography (hereinafter, abbreviated as GPC). For the measurement, a GPC apparatus manufactured by Tosoh Corporation was used, and measurement conditions and the like were as follows. Moreover, the degree of dispersion shown in the following synthesis examples of the present specification is calculated from the measured weight average molecular weight and the number average molecular weight.

[GPC condition]

GPC pipe column: Shodex [registered trademark] Asahipak [registered trademark] (Showa Denko (share) system)

Column temperature: 40 ° C

Solvent: N,N-dimethylformamide (DMF)

Flow rate: 0.6ml/min

Standard sample: standard polyethylene sample (Tosoh Co., Ltd.)

Detector: RI detector (Tosoh Co., Ltd., RI-8020)

[Thickness tester for photoresist underlayer film]

NanoSpec/AFT5100 (manufactured by Nanometrics)

[Examples] <Synthesis Example 1>

Monolyl propylene oxide propylene iso-cyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.) 7.0 g, 2,4-dihydroxybenzyl aldehyde (Wako Pure Chemical Industries, Ltd.) 3.47 g and chlorinated 0.28 g of benzyltriethylammonium (Tokyo Chemical Industry Co., Ltd.) was added to 14.43 g of cyclohexanone to dissolve it. After replacing the reaction vessel with nitrogen, the mixture was reacted at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 15,000 and a degree of dispersion of 4.1 in terms of standard polyethylene.

<Synthesis Example 2>

DG-DMH (diepoxypropyldimethylhydantoin, Nagase ChemteX (share)) 4.1 g, 2,4-dihydroxybenzaldehyde (Wako Pure Chemical Industries, Ltd.) 2.1 g and benzyl chloride 0.17 g of triethylammonium (Tokyo Chemical Industry Co., Ltd.) was added to 14.49 g of cyclohexanone to dissolve it. After replacing the reaction vessel with nitrogen, the mixture was reacted at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 32,000 and a degree of dispersion of 7.0 in terms of standard polyethylene.

<Synthesis Example 3>

1,4-BDDEP (1,4-bis(ethylene oxide-2-yloxy)butane, Yokkaichi synthesis), 4.1 g, 2,4-dihydroxybenzaldehyde (Wako Pure Chemical Industries, Ltd.) 2.7 g and benzyltriethylammonium chloride (Tokyo Chemical Industry Co., Ltd.) 0.23 g were added to 16.77 g of cyclohexanone to dissolve. After replacing the reaction vessel with nitrogen, the mixture was reacted at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 7,000 and a degree of dispersion of 2.2 in terms of standard polyethylene.

<Synthesis Example 4>

4.0 g of monoallyl digoxypropyl iso-cyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.), resorcin (Wako Pure Chemical Industries, Ltd.) 1.6 g, and benzyltriethyl chloride 0.17 g of chloramine (Tokyo Chemical Industry Co., Ltd.) was added to 13.47 g of cyclohexanone to dissolve it. After replacing the reaction vessel with nitrogen, the mixture was reacted at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 6,000 and a degree of dispersion of 2.6 in terms of standard polyethylene.

<Synthesis Example 5>

4.0 g of monoallyl digoxypropyl iso-cyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.), 1.8 g of gallic phenol (Wako Pure Chemical Industries, Ltd.), and benzyltriethylammonium chloride (Tokyo Chemical Industry Co., Ltd.) 0.17 g of cyclohexanone was added to dissolve it in 14.00 g. After the reaction vessel was replaced with nitrogen, the reaction was carried out at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 7,000 and a degree of dispersion of 3.0 in terms of standard polyethylene.

<Synthesis Example 6>

4.0 g of monoallyl digoxypropyl iso-cyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.), 2.7 g of 5-hydroxyisophthalic acid (Tokyo Chemical Industry Co., Ltd.), and benzyl trichloride 0.16 g of ethylammonium (Tokyo Chemical Industry Co., Ltd.) was added to 15.93 g of cyclohexanone to dissolve it. After the reaction vessel was replaced with nitrogen, the reaction was carried out at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 18,000 and a dispersion of 4.7 in terms of standard polyethylene.

<Synthesis Example 7>

Monoallyl digoxypropyl iso-cyanuric acid (manufactured by Shikoku Chemicals Co., Ltd.) 4.0 g, benzenetriol (alias: 1,3,5-trihydroxybenzene, Tokyo Chemical Industry Co., Ltd.) 1.8 g and 0.17 g of benzyltriethylammonium chloride (Tokyo Chemical Industry Co., Ltd.) were added to 14.12 g of cyclohexanone to dissolve. After replacing the reaction vessel with nitrogen, the mixture was reacted at 135 ° C for 4 hours to obtain a polymer solution. When the GPC analysis was carried out, the obtained polymer had a weight average molecular weight of 544 and a degree of dispersion of 1.1 in terms of standard polyethylene.

(Example 1)

3.03 g of a solution containing 0.56 g of the polymer obtained in the above Synthesis Example 1 was mixed with 0.014 g of 5-sulfuric acid, and 10.33 g of cyclohexanone and 5.70 g of propylene glycol monomethyl ether acetate were added thereto to dissolve. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Example 2)

3.00 g of a solution containing 0.55 g of the polymer obtained in the above Synthesis Example 2 was mixed with 0.014 g of 5-sulfuric acid, and 15.65 g of cyclohexanone was added thereto to dissolve. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Example 3)

3.00 g of a solution containing 0.52 g of the polymer obtained in the above Synthesis Example 3 was mixed with 0.013 g of 5-sulfulic acid, and 5.61 g of cyclohexanone and 5.21 g of propylene glycol monomethyl ether acetate were added thereto to be dissolved. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Example 4)

3.00 g of a solution containing 0.55 g of the polymer obtained in the above Synthesis Example 1 was mixed with 0.015 g of p-phenolsulfonic acid, and 10.33 g of cyclohexanone and 5.50 g of propylene glycol monomethyl ether acetate were added thereto to be dissolved. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Comparative Example 1)

3.01 g of a solution containing 0.51 g of the polymer obtained in the above Synthesis Example 4 was mixed with 0.013 g of 5-sulfulic acid, and 9.26 g of cyclohexanone and 5.06 g of propylene glycol monomethyl ether acetate were added thereto to dissolve. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Comparative Example 2)

3.10 g of a solution containing 0.48 g of the polymer obtained in the above Synthesis Example 5 was mixed with 0.012 g of 5-sulfulic acid, and 8.57 g of cyclohexanone and 4.75 g of propylene glycol monomethyl ether acetate were added thereto to dissolve. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.05 μm to form a composition for forming a photoresist film for lithography.

(Comparative Example 3)

To a solution containing 5.03 g (polymer concentration: 15% by mass) of a polymer having a structure of the following formula (14) (weight average molecular weight of 60,000 in terms of standard polyethylene), tetramethoxymethylacetylene urea (Cytec, Japan) was added. Industries (stock), trade name: POWDERLINK [registered trademark] 1174) 0.19g, pyridine p-toluenesulfonate 0.012g (Tokyo Chemical Industry Co., Ltd.), bisphenol S (Tokyo Chemical Industry Co., Ltd.) 0.024g, propylene glycol 12.67 g of monomethyl ether and 7.17 g of propylene glycol monomethyl ether acetate were used as a solution. Thereafter, it was filtered using a polyethylene microfilter having a pore size of 0.01 μm to prepare a composition for forming a photoresist underlayer film for lithography.

[Solution test for photoresist solvents]

The lithographic underlayer film forming compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were respectively applied onto a tantalum wafer of a semiconductor substrate by a spin coater. The tantalum wafer was placed on a hot plate and baked at 205 ° C for 1 minute to form a photoresist underlayer film. These photoresist lower layer films are immersed in cyclohexanone, and propylene glycol monomethyl ether (PGME) / propylene glycol monomethyl ether acetate (PGMEA) = 7 / 3 (mass ratio), whether or not the solvent is insoluble. Confirmation experiment.

As a result of the results shown in Tables 1 and 2, the photoresist underlayer film formed by using the photoresist underlayer film forming compositions of Examples 1 to 4 of the present invention has a film thickness variation of 1 nm or less (initial film). It is known that it has solvent resistance with a thickness of 1% or less. On the other hand, the photoresist underlayer film formed of the composition of the photoresist underlayer film of Comparative Example 1 and Comparative Example 2 was used, and as a result, solvent resistance was not obtained.

[Measurement of optical parameters]

The lithographic underlayer film forming compositions prepared in Examples 1 to 4 were respectively coated on a ruthenium wafer by a spin coater. The tantalum wafer was placed on a hot plate and baked at 205 ° C for 1 minute to form a photoresist underlayer film (film thickness: 0.05 μm). These resistive underlayer films were measured for refractive index (n value) and attenuation coefficient (k value) at a wavelength of 193 nm using a spectroscopic ellipsometer (manufactured by J.A. Woollam Co., Ltd., VUV-VASE VU-302). The results obtained are shown in Table 3.

[Determination of dry etching speed]

The lithographic underlayer film forming compositions prepared in Examples 1 to 4 were respectively coated on a ruthenium wafer by a spin coater. The tantalum wafer was placed on a hot plate and baked at 205 ° C for 1 minute to form a photoresist underlayer film (film thickness: 0.1 μm). Then, the dry etching rate (the amount of change in film thickness per unit time) was measured under the conditions of using a tetrafluoromethane in a dry etching gas system using a Japanese SCIENTIFIC (share) system and an RIE system ES401.

Further, a photoresist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: PAR710) was applied onto a tantalum wafer by a spin coater. The tantalum wafer was placed on a hot plate and baked at 90 ° C for 1 minute to form a photoresist film. Then, using the RIE system ES401 manufactured by SCIENTIFIC, Japan, the dry etching rate was measured under the conditions of using a dry etching gas system using tetrafluoromethane. Table 3 shows the results of comparing the dry etching rate of the photoresist underlayer film formed of the photoresist underlayer film of Examples 1 to 4 with the photoresist film (PAR710). In Table 3, the selection ratio indicates the dry etching rate of the photoresist underlayer film formed by the composition of the photoresist underlayer film of each example when the dry etching rate of the photoresist film (PAR710) is 1.0.

As shown in Table 3, the photoresist underlayer film obtained by forming the composition of the photoresist underlayer film of Examples 1 to 4 of the present invention has a sufficiently effective refractive index (n value) and attenuation coefficient for light of 193 nm. (k value), again, as a result of having a sufficient dry etching selectivity ratio for the photoresist film.

That is, the result is that the photoresist underlayer film obtained by forming the composition of the photoresist underlayer film of the present invention can shorten the time required for the removal of the photoresist by the dry etching of the underlayer film, and can also suppress the accompanying dry etching. The removal is required to cause a decrease in the film thickness of the photoresist film on the photoresist underlayer film.

[Measurement of Sublimation Quantity]

The photoresist underlayer film formation composition prepared in Example 4 and the photoresist underlayer film formation composition prepared in Comparative Example 3 as a comparison object were respectively coated by 1,500 rpm and 60 seconds by a spin coater. Spread on a 4 inch diameter wafer. The wafer device coated with the photoresist underlayer film forming composition is placed on a sublimation amount measuring device integrated with a heating plate (refer to the manual of International Publication No. 2007/111147), baked for 120 seconds, and the sublimate is collected to A QCM (Quartz Crystal Microbalance) sensor, that is, a crystal vibrator formed with an electrode. The QCM sensor uses a crystal vibrator on the surface (electrode) to which a sublimate is attached, and the mass variation of the crystal vibrator is changed (decreased) according to the mass of the crystal vibrator.

The detailed measurement procedures are as follows. The heating plate of the sublimation amount measuring device was heated to 205 ° C, and the pump flow rate was set to 1 m ³ /s. The first 60 seconds was placed in order to stabilize the device. Thereafter, the wafer coated with the photoresist underlayer film forming composition is quickly placed on the heating plate from the sliding opening, and the sublimation is carried out from the time point of 60 seconds to 180 seconds (120 seconds). Things. Further, the film thickness of the underlayer film formed on the wafer was 80 nm.

Further, the QCM sensor connected to the sublimation amount measuring device and the airflow attaching device (detecting portion) of the collecting funnel portion are used without the nozzle, and therefore, can be used from the sensor (crystal vibrator) The flow path (caliber: 32mm) of the air chamber unit with a distance of 30mm allows the airflow to flow without confusion. Further, in the QCM sensor, the electrode is made of a material containing aluminum and aluminum as a main component (AlSi), the diameter of the crystal vibrator (sensor diameter) is 14 mm, and the electrode diameter of the surface of the crystal vibrator is 5 mm, resonance cycle The number is 9MHz.

The change in the number of cycles obtained is converted into gram from the intrinsic value of the crystal vibrator used for the measurement, and the relationship between the amount of sublimation material and the elapsed time of the wafer on which the composition film is formed by the photoresist is formed. Table 4 shows the amount of sublimation (unit: ng: Nike) indicated by the measuring device from 0 seconds to 180 seconds in Example 4 and Comparative Example 3. In addition, the first 60 seconds is a time period in which the device is placed in a stable state (the wafer is not set), and the amount of the sublimation material shown in the measuring device is directly read even if it is a negative value. Therefore, the measured value from the time point of 60 seconds to 180 seconds after the wafer is placed on the heating plate is the measured value of the amount of sublimation.

As shown in Table 4, the photoresist underlayer film obtained by forming the composition of the photoresist underlayer film of Example 4 of the present invention was more preferable than the photoresist underlayer film obtained by forming the composition of the photoresist underlayer film of Comparative Example 3. The result of suppressing the occurrence of sublimate.

[Formation and Evaluation of Photoresist Patterns]

The photoresist underlayer film forming compositions prepared in the foregoing Examples 1 to 4 were coated on a germanium wafer by a spinner. The film was heated at 205 ° C for 1 minute on a hot plate to form a photoresist underlayer film having a film thickness of 50 to 80 nm. On the photoresist underlayer film, a commercially available photoresist solution (manufactured by JSR Co., Ltd., trade name: AR2772JN) was applied by a spin coater, and heated at 110 ° C for 90 seconds on a hot plate. A photoresist film (film thickness 0.21 μm) was formed.

Next, a scanner manufactured by Nikkon, NSR-S307E (wavelength: 193 nm, NA: 0.85, σ: 0.65/0.93 (ANNULAR)) was used, and exposure was performed through a photomask under predetermined conditions. The reticle is selected according to the type of photoresist pattern that should be formed. After exposure, the film was exposed to heat (PEB) at 105 ° C for 60 seconds on a hot plate. After cooling, in the 60 sec single puddle step of the industrial specification, tetramethylammonium hydroxide specified in 0.26 was used. The aqueous ammonium solution was developed as a developing solution. When the cross-sectional shape of the formed photoresist pattern and the substrate (矽 wafer) in the vertical direction was observed in the cross-sectional SEM, it was confirmed that the target photoresist pattern was formed. A cross-sectional SEM image of a photoresist pattern on a photoresist underlayer film formed using the photoresist underlayer film formation composition prepared in Example 1 is shown in Fig. 1.

Fig. 1 is a cross-sectional SEM image of a photoresist pattern on a photoresist underlayer film formed by forming a composition of a photoresist underlayer film prepared in Example 1.

Claims (18)

A photoresist forming underlayer film forming composition for lithography, characterized by having the following formula (1): (wherein R, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ and A ₆ each independently represent a hydrogen atom, a methyl group or an ethyl group, Q represents a divalent organic group, and n ₁ represents 1 to 4 The polymer, the sulfonic acid compound, and the solvent, each of which n ₂ and n ₃ each independently represent a number of 0 or 1, and m represents a repeating unit number and is 5 to 300). The lithographic underlayer film forming composition of claim 1 wherein the polymer has the following formula (1a): (wherein, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ , Q and m are polymers of a repeating structure represented by the formula (1)). A photoresist forming underlayer film forming composition for lithography, characterized by containing the following formulas (2) and (3): (In the formula (2), R represents a hydrogen atom, a methyl group or an ethyl group, n ₁ represents a number from 1 to 4, and n ₂ and n ₃ each independently represent a number of 0 or 1, in the formula (3), A ₁ , a polymer, a sulfonic acid compound, and two structural units represented by A ₂ , A ₃ , A ₄ , A ₅ and A ₆ each independently represent a hydrogen atom, a methyl group or an ethyl group, and Q represents a divalent organic group. Solvent. The lithographic underlayer film forming composition of claim 3, wherein the polymer comprises the following formulas (2a) and (3): (In the formula, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ , and Q are polymers of the structural unit of the two types shown in the formula (3). The lithographic underlayer film forming composition of claim 1 or claim 2, wherein in the above formula (1) or (1a), Q is the following formula (4): (wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a stretching phenyl group, an anthranyl group or a stretching group; The phenyl group, the extended naphthyl group and the fluorenyl group may be selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon number of 1 to The group represented by at least one group of 6 alkylthio groups, and n ₄ and n ₅ each independently represent a group represented by 0 or 1. The lithographic underlayer film forming composition of claim 1 or claim 2, wherein in the above formula (1) or (1a), Q is the following formula (5): Wherein X ₁ is the following formula (6) or the following formula (7): (wherein R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from a carbon atom. Substituting at least one group of a group of 1 to 6 alkyl groups, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms, or R ₁ and R _{2 are} bonded to each other to form a ring having a carbon number of 3 to 6 or a divalent group represented by the group. The lithographic underlayer film forming composition of claim 1 or claim 2, wherein in the above formula (1) or (1a), Q is the following formula (8): (wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and at least one group in which an alkylthio group having 1 to 6 carbon atoms is substituted. The lithographic underlayer film forming composition of claim 3 or claim 4, wherein in the above formula (3), Q is the following formula (4): (wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a phenylene group, an anthranyl group or a fluorenyl group, the aforementioned The phenyl group, the extended naphthyl group and the fluorenyl group are respectively selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon atom number of 1. Substituting at least one group of groups of alkylthio groups to 6 and n ₄ and n ₅ each independently represent a group represented by number 0 or 1. The lithographic underlayer film forming composition of claim 3 or claim 4, wherein in the above formula (3), Q is the following formula (5): Wherein X ₁ is the following formula (6) or the following formula (7): (wherein R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from a carbon atom. Substituting at least one group of a group of 1 to 6 alkyl groups, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms, or R ₁ and R _{2 are} bonded to each other to form a ring having a carbon number of 3 to 6 or a divalent group represented by the group. The lithographic underlayer film forming composition of claim 3 or claim 4, wherein in the above formula (3), Q is the following formula (8): (wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and at least one group in which an alkylthio group having 1 to 6 carbon atoms is substituted. The composition for forming a lithographic underlayer film for a lithography according to any one of claims 1 to 4, wherein the polymer is at least one compound represented by the following formula (9) and the following formula (10) At least one compound represented by: (wherein R represents a hydrogen atom, a methyl group or an ethyl group, n ₁ represents a number from 1 to 4, and n ₂ and n ₃ each independently represent a number of 0 or 1, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ and A ₆ each independently represent a reaction product of a hydrogen atom, a methyl group or an ethyl group, and Q represents a divalent organic group. The lithographic photoresist underlayer film forming composition according to claim 11, wherein the polymer is at least one compound represented by the following formula (9a) and at least one compound represented by the following formula (10). Compound: (wherein A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ and Q are the reaction products as defined in the above formula (10)). The lithographic underlayer film forming composition of claim 11 wherein Q in the above formula (10) is the following formula (11): (wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a phenylene group, an anthranyl group or a fluorenyl group, the aforementioned The phenyl group, the extended naphthyl group and the fluorenyl group are respectively selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon atom number of 1. Substituting at least one group of groups of alkylthio groups to 6 and n ₄ and n ₅ each independently represent a group represented by number 0 or 1. The photolithographic underlayer film forming composition of the lithography according to claim 12, wherein in the above formula (10), Q is the following formula (11): (wherein Q ₁ represents an alkylene group having 1 to 10 carbon atoms, a divalent organic group having an alicyclic hydrocarbon having 3 to 10 carbon atoms, a phenylene group, an anthranyl group or a fluorenyl group, the aforementioned The phenyl group, the extended naphthyl group and the fluorenyl group are respectively selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group and a carbon atom number of 1. Substituting at least one group of groups of alkylthio groups to 6 and n ₄ and n ₅ each independently represent a group represented by number 0 or 1. The lithographic underlayer film forming composition of claim 11 is as follows, wherein in the above formula (10), Q is the following formula (12): (wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and at least one group in which an alkylthio group having 1 to 6 carbon atoms is substituted. The photolithographic underlayer film forming composition of the lithography according to claim 12, wherein in the above formula (10), Q is the following formula (12): (wherein R ₃ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group or a phenyl group, and the aforementioned phenyl group may be selected from an alkyl group having 1 to 6 carbon atoms; A group represented by a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and at least one group in which an alkylthio group having 1 to 6 carbon atoms is substituted. A method for forming a photoresist pattern, which is characterized in that it is used for coating a photolithographic underlayer film forming composition according to any one of claim 1 to claim 16 on a semiconductor substrate and baking it to form a step of forming a photoresist film on the underlayer of the photoresist, a step of exposing the semiconductor substrate on which the photoresist underlayer film and the photoresist film are exposed, and exposing the photoresist film after exposure The manufacture of a semiconductor device in the step of developing. A method of forming a photoresist pattern according to claim 17, wherein the exposure is performed using an ArF excimer laser.