WO2006027996A1

WO2006027996A1 - Resist composition for euv and method of forming resist pattern

Info

Publication number: WO2006027996A1
Application number: PCT/JP2005/016011
Authority: WO
Inventors: Hideo Hada; Taku Hirayama; Daiju Shiono; Takeo Watanabe; Hiroo Kinoshita
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2004-09-09
Filing date: 2005-09-01
Publication date: 2006-03-16
Also published as: TW200617602A; TWI292085B; KR20070057211A; JP2006078744A

Abstract

A resist composition for EUV, characterized by comprising: a protected compound (A1) which is a polyhydric phenol compound (a) represented by the following general formula (I) in which part or all of the phenolic hydroxy groups have been protected by an acid-dissociable dissolution-inhibitive group; and an acid generator ingredient (B) which generates an acid upon exposure to light.

Description

Specification

EUV resist composition and resist pattern forming method

Technical field

The present invention relates to a resist composition for EUV and a resist pattern forming method used for EUV lithography.

This application claims priority based on Japanese Patent Application No. 2004-262,306 filed on September 9, 2004, the contents of which are incorporated herein by reference.

Background art

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has rapidly progressed due to advances in lithography technology.

As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, the power used in the past, typically ultraviolet rays such as g-line and i-line, has now begun mass production of semiconductor devices using KrF excimer laser and ArF excimer laser. More recently, a lithography process using EUV (Extreme Ultraviolet; wavelength of about 13.5 nm), which is the next generation technology of lithography process using ArF excimer laser (193 nm), and electron beam has been proposed and studied ( For example, see Patent Documents 1 to 3). EUV exposure is usually performed in a vacuum. Also, in EUV lithography, since EUV is highly linear, an exposure apparatus is usually configured using a reflection engineering system that uses a mirror such as a multilayer mirror.

[0003] On the other hand, as one of resist materials that can satisfy a high-resolution condition that can reproduce a pattern with a fine size, a base material component that has film-forming ability and changes in alkali solubility by the action of an acid. A chemically amplified resist containing an acid generator component that generates an acid upon exposure is known. Chemically amplified resists are classified into a negative type in which alkali solubility is reduced by exposure and a positive type in which alkali solubility is increased by exposure.

At present, resins are mainly used as the base component of chemically amplified resists. For example, in the case of positive type, the hydroxyl group of polyhydroxystyrene-based resin and the power of (meth) acrylic-based resin can be one of the loxy groups. The part protected with an acid dissociable, dissolution inhibiting group can be used (for example, (See Patent Documents 4 and 5).

However, when a pattern is formed using such a material, there is a problem that roughness is generated on the upper surface of the pattern or the surface of the side wall. Such roughness has not been a problem in the past. However, in recent years, with the rapid miniaturization of semiconductor elements and the like, higher resolution, for example, resolution with a dimension width of 90 nm or less, has been demanded, and accordingly, roughness has become a serious problem. For example, when forming a line pattern, the roughness of the surface of the side wall of the pattern, that is, the force that causes variation in the formed line width due to LER (line edge roughness), the management width of the variation in the line width is 10% of the dimension width. It is desired to be less than or equal to the degree. The smaller the pattern size, the greater the influence of LER. For example, when a line pattern having a dimension of about 90 nm is formed, it is desired that the management width of the variation in the line width is about lOnm or less. However, polymers that are generally used as base materials have an average square radius per molecule as large as several nanometers, and the above management range is only about several polymers. Therefore, as long as a polymer is used as the base material component, it is very difficult to reduce LER.

[0004] On the other hand, as a base material component, it has been proposed to use a low molecular weight material having an alkali-soluble group such as a hydroxyl group, part or all of which is protected with an acid dissociable, dissolution inhibiting group (example). For example, see Patent Document 6). Such a low molecular weight material is expected to have a small contribution to the increase in LER due to the low mean molecular diameter due to its low molecular weight.

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-177537

Patent Document 2: JP 2003-140361 A

Patent Document 3: Japanese Unexamined Patent Publication No. 2003-75998

Patent Document 4: JP-A-5-249682

Patent Document 5: Japanese Patent No. 2881969

Patent Document 6: Japanese Unexamined Patent Application Publication No. 2002-099088

Disclosure of the invention

Problems to be solved by the invention

[0005] However, according to the study of the present inventors, when EUV lithography is performed using a chemically amplified resist, particularly when a low-molecular material is used as a base material component, the resist during exposure is registered. There is a problem that degassing occurs from the strike film. Such degassing causes problems such as weakening the exposure light reaching the substrate during exposure and contaminating the mirror and the mask, making it impossible to perform stable exposure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an EUV resist composition and a resist pattern forming method that are suitable for lithography using EUV with less outgassing.

Means for solving the problem

[0006] As a result of intensive studies, the present inventors have found that a protector in which a phenolic hydroxyl group of a polyhydric phenol compound having a specific structure is protected with an acid dissociable, dissolution inhibiting group is a degassing material with little degassing. As a result, the present invention was completed.

That is, the first aspect of the present invention is the following general formula (I)

[0007] [Chemical 1]

[In the formula (I), R to R are each independently an alkyl group having 1 to 10 carbon atoms or aromatic carbon.

11 17

A hydride group which may contain heteroatoms in its structure; g and j are each independently an integer of 1 or more, k and q are 0 or an integer of 1 or more, and g + j + k + q is 5 or less; h is an integer of 1 or more, 1 and m are each independently 0 or an integer of 1 or more, and h + 1 + m force or less; i is 1 or more N and o are each independently an integer of 0 or 1 and i + n + o is 4 or less; p is 0 or 1; X is the following general formula (la) or (Lb)

[0008] [Chemical 2]

(In the formula (la), R 1 and R 2 are each independently an alkyl group having 1 to 10 carbon atoms or aromatic carbon.

18 19

A hydrogen halide group that may contain heteroatoms in the structure; r, y, and z are each independently 0 or an integer of 1 or more, and r + y + z is 4 or less). A protected body (A1) in which part or all of the phenolic hydroxyl groups in the polyvalent phenolic compound (a) represented by the formula (1) are protected with acid dissociable, dissolution inhibiting groups; An EUV resist composition comprising an acid generator component (B) that generates

In addition, the second aspect of the present invention is a method in which the EUV resist composition according to any one of claims 1 to 4 is applied on a substrate, pre-betaized, and EUV is selectively exposed, and then PEB is applied. The resist pattern forming method is characterized in that a resist pattern is formed by performing (post-exposure heating) and alkali development.

The invention's effect

The present invention can provide a resist composition for EUV and a resist pattern forming method suitable for lithography using EUV with less outgassing.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] <EUV resist composition>

In the EUV resist composition of the present invention, part or all of the phenolic hydroxyl groups in the polyvalent phenolic compound (a) represented by the above general formula (I) are protected with acid dissociable, dissolution inhibiting groups. A resist composition for EUV, comprising: a protective body (A1); and an acid generator component (B) that generates an acid upon exposure (hereinafter also referred to as component (B)).

Here, the polyhydric phenol compound (a) is the one before being protected with the acid dissociable, dissolution inhibiting group, and the one protected with the acid dissociable, dissolution inhibiting group is the protector (A1) It is.

In the EUV resist composition of the present invention, the component (B) force is generated by exposure. When the acid acts on the protective body (Al), the acid dissociable, dissolution inhibiting group is dissociated, thereby changing the entire protective body (A1) from alkali-insoluble to alkali-soluble. For this reason, when the resist film having the resist composition strength is selectively exposed or heated after the exposure in addition to the exposure, the exposed portion turns into alkali-soluble while the resist pattern is formed. Since the alkali remains insoluble and does not change, a positive resist pattern can be formed by alkali development.

In the above general formula (I), R 1 to R 5 are each independently linear, branched or cyclic,

11 17

A lower alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, a cyclic alkyl group having 5 to 6 carbon atoms, or an aromatic hydrocarbon group. The alkyl group or aromatic hydrocarbon group may contain a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom in its structure. Examples of the aromatic hydrocarbon group include a full group, a tolyl group, a xylyl group, a mesityl group, a phenethyl group, and a naphthyl group.

g and j are each independently an integer of 1 or more, preferably 1 or 2, k and q are each independently 0 or 1 or more, preferably an integer not exceeding 2, and g + j + k + q Is 5 or less.

h is an integer of 1 or more, preferably 1 to 2, 1, and m are each independently 0 or 1 or more, preferably an integer not exceeding 2, and h + 1 + m is 4 or less.

i is an integer of 1 or more, preferably 1 to 2, n and o are each independently 0 or 1 or more, preferably an integer not exceeding 2, and i + n + o is 4 or less.

p is 0 or 1, preferably 1.

X is a group represented by the above general formula (la) or (lb). In the formula (la), R 1 and R are the above

18 19

Like R to R, each independently an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon

11 17

It is a basic group and may contain a hetero atom in its structure. R, y, and z are each independently an integer of 0 or 1 and r + y + z is 4 or less.

[0013] Among these, R is a cycloalkyl group, the number of i is 1, and R is lower alkyl

11 12

A group in which the number of k is 1 and the number of g is 1 is preferable.

More preferably, R is a cycloalkyl group, the number of j is 1, and R is a lower alkyl group.

11 12

The number of k is 1, the number of g is 1, the power q, 1, m, n, and o force, and h and i are A compound of 1 is preferable because a fine pattern can be formed with high resolution with reduced LER.

X is preferably the general formula (lb).

Among the polyvalent phenolic compounds (a), the most preferable one is the polyvalent phenolic compound represented by the following formula (I 1) and the polyvalent phenol represented by (I 2) Phenolic compound.

[0015] [Chemical 3]

[0016] In the present invention, the polyvalent phenol compound (a) preferably has a molecular weight of 300 to 2500, more preferably 450 to 1500, and even more preferably 500 to 1200!

When the molecular weight is 2500 or less, LER (line edge roughness) is reduced, the pattern shape is improved, and the resolution is also improved. In addition, when it is 300 or more, a resist pattern having a good profile shape can be formed.

[0017] Further, the polyhydric phenol compound (a) preferably has a molecular weight dispersity (MwZMn) of 1.5 or less because LER is reduced. This is because the polyphenolic compound (a) has a dispersity of 1. Multiple protectors with different numbers of phenolic hydroxyl groups (protection numbers) that are protected by acid dissociable, dissolution inhibiting groups in polyphenolic materials by having a narrow molecular weight distribution of 5 or less (A1) Even if it is contained, it is considered that the alkali solubility of each protector (A1) becomes relatively uniform. The smaller the degree of dispersion, the more preferable it is, and preferably 1.4 or less, and most preferably 1.3 or less.

The dispersity is generally used for polydisperse compounds such as polymers, but even monodisperse compounds may contain impurities such as by-products during production and residual starting materials. Therefore, when analyzed by gel permeation chromatography (GPC) or the like, a distribution may appear in its molecular weight. That is, in the case of a monodispersed compound, a dispersity of 1 means that the purity is 100%, and the greater the dispersity, the greater the amount of impurities.

In the present invention, the degree of dispersion is generally used for a compound that exhibits such an apparent molecular weight distribution.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer to be measured can be calculated by measuring Mw and Mn by, for example, GPC and determining the MwZMn ratio.

The degree of dispersion is determined by synthesizing the polyhydric phenolic compound (a), which is the final target product, and then purifying and removing reaction by-products and impurities, or by using a known method such as molecular weight fractionation. The quantity part can be removed and adjusted.

Further, the polyvalent phenolic compound (a) needs to be a material capable of forming an amorphous film by spin coating. Here, an amorphous film means an optically transparent film that does not crystallize. The spin coating method is one of the commonly used thin film forming methods, and whether or not the polyhydric phenol compound is a material that can form an amorphous film by the spin coating method is determined by the 8-inch silicon coating method. This can be determined by whether or not the coating film formed on the wafer by spin coating is transparent. More specifically, for example, the determination can be made as follows. First, the polyhydric phenol material is generally used as a resist solvent. For example, a mixed solvent of ethyl lactate Z propylene glycol monomethyl ether acetate = 40Z60 (mass ratio) (hereinafter abbreviated as ΕΜ). ) Is dissolved to a concentration of 14% by mass and subjected to ultrasonic treatment (dissolution treatment) using an ultrasonic cleaner. The solution is spin-coated on the wafer at 1500 rpm, and optionally a dry baking (PAB: Post Applied Bake) is applied at 110 ° C for 90 seconds. Then, it is confirmed whether an amorphous film is formed depending on whether it is transparent. A transparent, cloudy film is not a monolithic film.

In the present invention, it is preferred that the polyphenolic compound (a) has good stability of the amorphous film formed as described above. Even after being left for a week, it is preferable that the amorphous state be maintained.

[0019] The protector (A1) is protected by substituting part or all of the hydroxyl groups of the phenolic hydroxyl group of the polyhydric phenol compound (a) with an acid dissociable, dissolution inhibiting group. The acid dissociable, dissolution inhibiting group is not particularly limited, and is proposed for hydroxystyrene-based resins and (meth) acrylic acid-based resins used in chemically amplified resist compositions for KrF and ArF. It can be used by appropriately selecting from unreasonable forces.

Specific examples include a chain alkoxyalkyl group, a tertiary alkyloxycarbonyl group, a tertiary alkyl group, a tertiary alkoxycarboalkyl group, and a cyclic ether group.

[0020] The chain alkoxyalkyl group includes: 1 ethoxyethyl group, 1 ethoxymethyl group, 1-methoxymethylethyl group, 1-methoxymethyl group, 1 isopropoxycetyl group, 1 methoxypropyl group, 1 ethoxypropyl group, 1 n Butoxetyl group and the like.

Examples of the tertiary alkyloxycarbonyl group include a tert-butyloxycarboxyl group and a tert-amyloxycarboxyl group.

Tertiary alkyl groups include chain tertiary alkyl groups such as tert butyl group and tert-amyl group, fatty acids such as 2-methyladamantyl group and 2-ethyladadamantyl group. And tertiary alkyl groups containing an aromatic polycyclic group.

Examples of the tertiary alkoxy carboalkyl group include a tert butyloxy carboxymethyl group, a tert-amyloxy carbonylmethyl group, and the like.

Examples of the cyclic ether group include a tetrahydrovinyl group and a tetrahydrofuranyl group. Among these, 1 ethoxyethyl group and 1 ethoxymethyl group are preferred because chain alkoxyalkyl groups are preferred because they have excellent dissociation properties, can improve the uniformity of the protector (A1), and can improve LER. preferable.

[0021] Further, in the protected body (A1), a plurality of polyhydric phenolic compounds having different numbers of phenolic hydroxyl groups protected by acid dissociable, dissolution inhibiting groups (protection number) (hereinafter referred to as isomers) Is included, the closer the number of protected isomers, the better the effect of the present invention.

The ratio of each isomer in the protected form (A1) can be measured by means such as reverse phase chromatography.

[0022] The protector (A1) is, for example, one or two or more polyphenolic compounds (a), wherein all or part of the phenolic hydroxyl groups are acid-dissociable by a known method. It can be produced by a method of protecting with a dissolution inhibiting group.

In the protected body (A1), the number of protected isomers can be adjusted by the conditions of the method of protecting with the acid dissociable, dissolution inhibiting group.

[0023] The content of the protective body (A1) in the EUV resist composition of the present invention may be adjusted according to the resist film thickness to be formed.

[0024] The EUV resist composition of the present invention comprises an unprotected body (A2), wherein the phenolic hydroxyl group in the polyhydric phenol compound (a) is protected with an acid dissociable, dissolution inhibiting group. You may have.

The unprotected body (A2) is one in which the hydroxyl group of the phenolic hydroxyl group of the polyhydric phenol compound (a) is not protected at all by the acid dissociable, dissolution inhibiting group, that is, the polyhydric phenol compound (a). It is.

In the EUV resist composition of the present invention, the smaller the proportion of unprotected body (A2), the better. For example, the ratio of unprotected body (A2) to the total amount of the above-mentioned protected body (A1) and unprotected body (A2). The ratio is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 10% by mass or less, and most preferably 0% by mass. When the ratio of the unprotected body (A2) is 60% by mass or less, LER can be reduced and the resolution is excellent when a pattern is formed. The ratio of unprotected body (A2) to the total amount of protected body (A1) and unprotected body (A2) is, for example, removal of unprotected body (A2) by gel permeation chromatography (GPC), etc. Can be adjusted.

The ratio of the unprotected body (A2) to the total amount of the protected body (A1) and the unprotected body (A2) can be measured by means such as reverse phase chromatography.

[0025] In the EUV resist composition of the present invention, the protection rate of the phenolic hydroxyl group of the polyhydric phenol compound (a) is 5 to 50 mol% in view of resolution and roughness reduction effect. preferred member 7 and more preferably 30 mol ^_0/0.

[0026] As the component (B), known acid generators used in conventional chemically amplified resist compositions can be used without particular limitation. Examples of such acid generators include so-called onium salt acid generators such as odonium salts and sulfo salt, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes. There are various known diazomethane acid generators such as poly (bissulfo) diazomethanes, nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, and disulfone acid generators.

[0027] Specific examples of the acid salt-based acid generator include trifluoromethanoate sulfonate or nonafluorobutane sulfonate of diphenylodium, trifluoromethanesulfonate or nona of bis (4-tert butylphenol) ododonium. Fluorobutane sulfonate, triphenyl sulfone trifluoromethane sulfonate, its heptafluoropropane sulfonate, or its nonafluorobutane sulfonate, tri (4 methylphenol) snorephonium trifanololomethane sulphonate , Its heptafluororenopropane sulfonate or its nonafluorobutane sulfonate, dimethyl (4-hydroxynaphthyl) snorephonium trifanololemethane sulfonate, its heptafluororenopropane sulfonate Or its nonafluorobutane sulfonate, monophenyl dimethyl sulfone trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, diphenyl monomethyl sulfone Trifluoromethane sulfonate, heptafluoropropane sulfonate or nonafluorobutane sulfonate, trifluoro of (4 methylphenol) diphenylsulfone Methane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenol) diphenyl sulfone trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4 Examples thereof include trifluoromethane sulfonate of tert-butyl) phenol sulfone, heptafluoropropane sulfonate or nonafluorobutane sulfonate thereof.

Specific examples of oxime sulfonate-based acid generators include _α- (P-toluenesulfo-luoximino) -benzyl cyanide, a- (p-chlorobenzenebenzene-sulfoximino) -benzil cyanide, _a- ( 4-Nitrobenzenesulfo-ruximino) -Benzyl cyanide, a- (4-Nitro-2-trifluoromethylbenzenesulfo-ruximino) -Benzyl cyanide, a- (Benzenesulfo-ruximino) -4-Black mouth Benzyl cyanide, a-(Benzenesulfo-ruximino)-2, 4-dichlorobenzil cyanide, a-(Benzenesulfo-ruxinomino)-2, 6 -dichlorobenzil cyanide, a-(Benzenesulfo- (Luoxyimino) -4-methoxybenzyl cyanide, a- (2-chlorobenzenesulfo-Luoxyimino) -4-methoxybenzil cyanide, a- (Benzenesulfo-Luoxy) B) -Chen-2-ylacetonitrile, a- (4-dodecylbenzenesulfo-ruximino) -benzyl cyanide, a-[(p-toluenesulfo-ruximino) -4-methoxyphenyl] acetonitrile, at- [(Dodecylpen senesulfo-ruximino) -4-methoxyphenyl] acetonitrile, at- (tosyloxymino) -4-chelciado, _a- (methylsulfo-ruximino) -1-cyclopentalacetonitrile, (X- ( Methylsulfo-ruximino)-1 -cyclohex-l-acetonitrile, a-(Methylsulfo-ruximino)-1 -cycloheptulacetonitrile, a-(Methylsulfo-ruximino)-1 -cyclootatulacetonitrile, _a- (Trifluoromethylsulfo-roximino)-1 -cyclopenteru-acetonitrile, a-(Trifluoro Methylstyrene sulfo - Ruokishiimino) - hexyl § Seto nitrile cyclohexane, a - (Echirusuruho - Ruokishii amino) - E chill § Seto nitrile, _a - (propylsulfonyl - Ruokishiimino) - Kishirusuruhoniru (cyclohexane - propyl § Seto nits Lil, a Oxymino) -cyclopentylacetonitrile, a- (cyclohexylsulfo-oxyximino) -cyclohexylhexonitrile, bis- (cyclohexylsulfo-ruximino) -1-cyclopentyl-acetonitrile, a- (ethylsulfur) (Holoxymino)-1 -Cyclopenta-acetonitrile, H-(Isopropylsulfo-oxyximino)-1 -Cyclopenta-Lucetonitrile, (X-(η-Butylsulfo-Luoxyimino)-1 -Cyclopenta-Luacetonitrile, at-(Ethylsulfo- (Luoxyimino)-1 -Cyclohexyl-Luacetonitrile, OC-(Isopropylsulfo-Luoxyimino)-1 -Cyclohexe-Luaceto-Tolyl, _α- (η-Butylsulfo-Luoxyimino)-1 -Cyclohexyl-Luacetonitrile, _α — (Methylsulfo-ruximino) Phenylacetonitrile, α (Methylsulfonyloxyximino) -ρ-Methoxyphenylacetonitrile, α (Trifluoromethylsulfo-luoxyimino) Phenylacetonitrile, α (Trifluoromethylsulfoxy-luminimino) ρ - Examples thereof include toxiphenylacetonitrile, （(ethylsulfo-luoxyimino) -ρ-methoxyphenylacetonitrile, (X- (propylsulfo-loxyimino) ρ-methylphenylacetonitrile, α (methylsulfo-luoxyimino) -ρ bromo-fertonitrile and the like. Of these, α (methylsulfo-oxyximino) mono-methoxyphenylacetonitrile is preferred.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfol-diazomethanes include bis (isopropylsulfol) diazomethane, bis (ρ toluenesulfol) diazomethane, and bis (1,1- Examples thereof include dimethylethylsulfol) diazomethane, bis (cyclohexylsulfol) diazomethane, and bis (2,4 dimethylphenylsulfol) diazomethane.

Poly (bissulfonyl) diazomethanes include, for example, 1,3 bis (phenylsulfo-diazomethylsulfol) propane (a compound with a structure shown below), decomposition point 135 ° C. ), 1,4 bis (phenylsulfol diazomethylsulfol) butane (Compound B, decomposition point 147 ° C), 1,6 bis (phenolsulfol diazomethylsulfol) hexane (Compound C, melting point 132 ° C, decomposition point 145 ° C), 1,10 bis (phenolsulfol diazomethylsulfol) decane (compound D, decomposition point 147 ° C), 1,2 bis (Cyclohexylsulfol diazomethylsulfol) ethane (Compound E, decomposition point 149 ° C), 1,3 bis (cyclohexylsulfoldiazomethylsulfol) propane ( Compound F, decomposition point 153 ° C), 1, 6 bis (cyclohexylsulfol diazomethylsulfol) hexa (I 匕合 product G, mp 109 ° C, decomposition point 122 ° C), 1, 10-bis (Kishirusuruho cyclohexane - Rujiazomechi (Lusulfonyl) decane (I compound H, decomposition point 116 ° C).

[Chemical 4]

[0031] In the present invention, it is preferable to use, as the component (B), an onium salt having a fluorinated alkyl sulfonate ion as an ion.

[0032] As the component (B), one type of acid generator may be used alone, or two or more types may be used in combination. The content of component (B) is 0.5 to 30 parts by mass, preferably 110 parts by mass with respect to 100 parts by mass of component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, it is preferable because a uniform solution can be obtained and storage stability is improved.

[0033] In the EUV resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter, (

D) component and i) can be blended.

Since a wide variety of components (D) have already been proposed, any known one can be used. For example, n xylamine, n ptylamine, n-octylamine, n-noramine, n- Monoalkylamines such as decylamine; dialkylamines such as jetylamine, di-n-propylamine, di-n-ptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri- _n -propyl Trialkylamines such as triamine, tri- _n- butyramine, tri- _n- xylamine, tri- _n- pentylamine, tri- _n- ptylumamine, tri- _n- octylamine, tri- _n- nonylamine, tri- _n -de-force-lamine, tri- _n -dodecylamine Diethanolamine, triethanolamine, diisopropano Amin, triisopropanolamine § Min, di one n- OTA Tanoruamin, alkyl alcohols § Min such tree n- O click pentanol § Min like et be. Of these, secondary aliphatic amines are most preferred, and tri-n-octylamine, which is more preferred to trialkylamines having a carbon number of 510, which are preferred to tertiary aliphatic amines.

These can be used alone or in combination of two or more. Component (D) is usually used in the range of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A).

[0034] In addition, the EUV resist composition of the present invention includes, as an optional component, for the purpose of preventing sensitivity deterioration due to the blending of the component (D), and improving the resist pattern shape, retention stability, and the like. , Organic carboxylic acids or phosphorus oxo acids or derivatives thereof (E) (hereinafter (

E) component)). The component (D) and the component (E) can be used in combination, or any one of them can be used.

Examples of organic carboxylic acids include malonic acid, succinic acid, malic acid, succinic acid, and benzoic acid. Acid, salicylic acid and the like are preferred.

Phosphoric acid or its derivatives include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenol ester and other phosphoric acid or derivatives such as those esters, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid Phosphonic acid such as n-butyl ester, phenol phosphonic acid, diphosphoric phosphonic acid ester, dibenzyl phosphonic acid ester and derivatives thereof, phosphinic acid such as phosphinic acid, phenol phosphinic acid and the like And derivatives such as esters, of which phosphonic acid is particularly preferred.

Component (E) is used in a proportion of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A).

[0035] The EUV resist composition of the present invention further has, as desired, miscible additives such as an additional resin for improving the performance of the resist film and an interface for improving the coating property. An activator, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

Examples of the additional resin include those proposed as base resins for conventional chemically amplified KrF positive resist compositions, ArF positive resist compositions, and the like.

The ratio of the additional resin should be within a range that does not impair the effects of the present invention. For example, it is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the resist composition. .

The EUV resist composition of the present invention can be produced by dissolving the above materials in an organic solvent.

As the organic solvent, it is sufficient if each component to be used can be dissolved into a uniform solution. Conventionally, any one or two of the known solvents for chemically amplified resists can be used. These can be appropriately selected and used.

For example, latones such as γ-butyrolatatane, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol Monoacetate, propylene glycol, propylene glycol monoacetate, dipropy Polyhydric alcohols such as lenglycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, Mention may be made of esters such as methyl lactate, ethyl acetate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, and the like.

These organic solvents can be used alone or as a mixed solvent of two or more.

[0037] A mixed solvent obtained by mixing propylene glycol monomethyl ether acetate (PGMEA) and a polar solvent is preferable. The mixing ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Preferably within range! /.

More specifically, when EL is added as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. ,.

In addition, as the organic solvent, a mixed solvent of at least one selected from among PGMEA and EL and γ-petit-mouth rataton is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70: 30-95: 5.

[0038] In the present invention, in particular, one or more selected from propylene glycol monomethyl ether (PGME), methyl amyl ketone (ブチル), butyl acetate (BuOAc), and 3-methylmethoxypropionate (MMP) are mainly used. An organic solvent contained as a component can be preferably used.

By using such a specific organic solvent as the main component in the resist solvent, contaminants are unlikely to be generated in situations where the exposure system such as EUV or electron beam must be in a vacuum state. The reason is presumed that these organic solvents tend to volatilize under heating conditions that require EUV and electron beam in the exposure process. These organic solvents are industrially preferable in terms of safety.

Specifically, one or more specific forces selected from the above propylene glycol monomethyl ether (PGME), methylamyl ketone (MAK), butyl acetate (BuOAc), and 3-methylmethoxypropionate (MMP) 70 mass% or more , Preferably 80% by weight or more, more preferably 9 It is preferable to be 0% by mass or more.

[0039] The amount of the organic solvent used is not particularly limited, and is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. Is used in a range of 2 to 20% by mass, preferably 5 to 15% by mass.

[0040] <Resist pattern formation method>

The resist pattern forming method of the present invention can be performed, for example, as follows. That is, first, a EUV resist composition useful for the present invention is coated on a substrate such as a silicon wafer with a spinner or the like, and is subjected to pre-beta under a temperature condition of 80 to 150 ° C, preferably 130 to 150 ° C. 40 to 120 seconds, and preferably for 60 to 90 seconds, for example by an EUV exposure apparatus which was selectively exposed through a desired mask pattern in a vacuum (e.g. ^{^{1 X 10 _7 ~1 X 10 _5}} Pa) Thereafter, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, under a temperature of 80 to 150 ° C.

Then alkali developing solution, for example 0.1 to 10 mass ^_0/0 tetramethylammonium - developing is conducted using an Umuhido port Kishido solution. In this way, a resist pattern faithful to the mask pattern can be obtained.

An organic or inorganic antireflection film can be provided between the substrate and the coating layer of the resist composition.

[0041] As described above, the EUV resist composition and resist pattern forming method of the present invention are suitable for lithography using EUV with less degassing during exposure. Further, the protective body (A1) The polyhydric phenolic compound (a), which is a material for the above, can be synthesized very easily, with good yield and purity, and can be produced stably and inexpensively industrially.

Example

Examples of the present invention will be described below, but the scope of the present invention is not limited to these examples.

[Reference Example 1]

100 parts by mass of a polyhydric phenolic compound represented by the above formula (I 1) (molecular weight 981: hereinafter abbreviated as low molecular weight compound (a-1)) and 10 parts by mass of trisulfol sulfomononafluo A resist composition prepared by dissolving rho-n-butanesulfonate (hereinafter abbreviated as TPS-PFBS) and 1 part by mass of tri-n-octylamine in 2000 parts by mass of propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMEA) A solution was obtained.

[0043] (Change in total pressure)

The obtained resist composition solution was applied on a silicon substrate so as to have a film thickness of 10%, and heated for 90 seconds at a temperature of 130 ° C.

, In the ^{pressure: 1 X 10 _7 ~1 X 10} _5 Pa, temperature: under the conditions of room temperature (25 ° C), Hyogo College - at Yusubaru radiation optical facility using light having a wavelength of 13. 5 nm The exposure was performed for 60 seconds. At this time, before and after exposure, measure the amount of change in the total pressure in the chamber where the substrate in the apparatus is placed, and obtain the value obtained by subtracting the total pressure before exposure from the total pressure after exposure as the total pressure change amount. It was. The results are shown in Table 1.

[0044] [Reference Example 2]

Reference example except that the low molecular weight compound (a-1) was used instead of the low molecular weight compound (a-1) (molecular weight 106 1: hereinafter referred to as low molecular weight compound (a'-1)). A resist composition solution was prepared in the same manner as in 1, and the same evaluation was performed. The results are shown in Table 1.

[0045] [Chemical 5]

[In the formula (Π), R is a group represented by the following formula (Ila). ]

[0046] [Chemical 6]

(Ila)

[0047] [Table 1]

[0048] From the results in Table 1, it can be seen that the resist composition of Reference Example 1 using the low molecular weight compound (a-1) as a base component suppressed degassing with a small total pressure change. . On the other hand, in Reference Example 2 using the low molecular weight compound (a′-1) not included in the general formula (I), the total pressure change amount was about twice as large as that in Reference Example 1.

In Reference Example 1 and Reference Example 2, unprotected low molecular weight compounds were used for the purpose of excluding the influence of the protection rate on degassing.

[0049] [Synthesis Example (Production Example of Protective Body (A1))]

10 g of the low molecular weight compound (a-1) was dissolved in 33 g of tetrahydrofuran, and 1.8 g of ethyl birue ether was added thereto and reacted at room temperature for 12 hours with stirring. After completion of the reaction, extraction and purification were carried out using a water-Z ethyl acetate system. As a result, 10.lg of a protected body (hereinafter abbreviated as protected body (a2)) in which a part of the phenolic hydroxyl group of the low molecular weight compound (a-1) was protected with a 1-oxytoxyl group was obtained.

The obtained protector (a-2)! / By the proton NMR of JEOL 400MHz, the number of phenolic hydroxyl groups in the protector (a-2) and the phenol protected with 1 ethoxyethyl group When the number of ionic hydroxyl groups was measured and the protection rate (mol%) was determined, it was 19.9 mol%. The protection rate is {1 the number of phenolic hydroxyl groups protected with 1 ethoxyethyl group Z (the number of phenolic hydroxyl groups + the number of phenolic hydroxyl groups protected with 1-ethoxyethyl group)} X 100.

[0050] [Example 1]

A resist composition solution was prepared and evaluated in the same manner as in Reference Example 1 except that the protector (a-2) obtained in Synthesis Example was used instead of the low molecular compound (a-1). . The results are shown in the table Shown in 2.

[0051] [Comparative Example 1]

Instead of the low molecular weight compound (a-1), 60 mol% of the hydroxyl group of the low molecular weight compound (molecular weight 54 5) represented by the following formula (ΠΙ) is protected with CH COO-C (CH). (Hereafter,

2 3 3

A resist composition solution was prepared in the same manner as in Reference Example 1 except that a protective body (abbreviated as “a′-2”) was used, and the same evaluation was performed. The results are shown in Table 2.

[0052] [Chemical 7]

[0053] [Table 2]

[0054] From the results shown in Table 2, the resist composition of Example 1 using the protector (a-2) as the base material component was a low molecular compound protector (a ' It can be seen that compared with Comparative Example 1 using 2), degassing was suppressed because the total pressure change was small.

Industrial applicability

[0055] The resist composition and the resist pattern forming method of the present invention are the same as those of EUV lithography. It is applied to the EUV resist composition and resist pattern forming method used.

Claims

The scope of the claims

The following general formula (I)

11 17

[Chemical 2]

18 19

And a heteroatom in the structure thereof; r, y, and z are each independently 0 or an integer of 1 or more, and r + y + z is 4 or less) Is a group A protective body (A1) in which a part or all of the phenolic hydroxyl groups in the polyphenolic compound (a) to be produced are protected with an acid dissociable, dissolution inhibiting group, and an acid generator component that generates an acid upon exposure ( A resist composition for EUV, comprising B).

[2] The EUV resist composition according to [1], wherein the polyvalent phenolic compound (a) has a molecular weight of 300 to 2500.

[3] The EUV resist composition according to claim 1 or 2, wherein the polyvalent phenol compound (a) has a molecular weight dispersity of 1.5 or less.

[4] The EUV resist composition according to claim 1 or 2, further comprising a nitrogen-containing organic compound (D).

[5] The EUV resist composition according to claim 1 or 2 is applied onto a substrate and pre-betaized.

A method of forming a resist pattern, comprising selectively exposing EUV, then applying PEB (post-exposure heating), and alkali developing to form a resist pattern.