WO2006095540A1

WO2006095540A1 - Positive resist composition and method for forming resist pattern

Info

Publication number: WO2006095540A1
Application number: PCT/JP2006/302558
Authority: WO
Inventors: Akiyoshi Yamazaki; Waki Ohkubo; Naoto Motoike; Satoshi Maemori; Yuichi Suzuki
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2005-03-04
Filing date: 2006-02-14
Publication date: 2006-09-14
Also published as: TW200643627A; JP4184352B2; JP2006243474A; KR100881304B1; TWI302639B; KR20070101367A

Abstract

Disclosed is a positive resist composition comprising a resin component (A) whose alkali solubility is increased by the action of an acid, and an acid generator component (B) which generates an acid when exposed to light. This positive resist composition is characterized in that the resin component (A) comprises a first resin component (A1) having a first constitutional unit derived from a hydroxystyrene, a second constitutional unit derived from a (meth)acrylate having an alcoholic hydroxyl group, and a third constitutional unit wherein the hydroxyl group of the constitutional unit derived from a hydroxystyrene is protected by an acid-cleavable dissolution inhibiting group and/or a fourth constitutional unit wherein the alcoholic hydroxyl group of the constitutional unit derived from a (meth)acrylate having an alcoholic hydroxyl group is protected by an acid-cleavable dissolution inhibiting group, and a second resin component (A2) having a fifth constitutional unit derived from a hydroxystyrene and a sixth constitutional unit wherein the hydroxyl group of the constitutional unit derived from a hydroxystyrene is protected by an acid-cleavable dissolution inhibiting group.

Description

Specification

Positive resist composition and resist pattern forming method

Technical field

[0001] The present invention relates to a positive resist composition and a resist pattern forming method using the same.

This application claims priority based on Japanese Patent Application No. 2005-060518 filed on Mar. 4, 2005, 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, 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, in the past, ultraviolet rays typified by g-line and i-line were used, but now KrF excimer laser (248 nm) has been introduced, and ArF excimer laser (193 nm) has begun to be introduced. Les.

[0003] As one of resist materials that satisfy the high-resolution conditions that can reproduce patterns with fine dimensions, a base resin that changes alkali solubility under the action of an acid and an acid generator that generates an acid upon exposure to light. A chemically amplified resist composition dissolved in an organic solvent is known.

A chemically amplified positive resist composition, which is proposed as a resist material suitable for exposure using a KrF excimer laser, is generally used as a base resin for acid dissociation of a part of the hydroxyl groups of a polyhydroxystyrene resin. Those protected with a soluble dissolution inhibiting group are used (for example, see Patent Document 1).

The acid dissociable, dissolution inhibiting group is represented by a so-called acetal group such as a chain ether group typified by 1-ethoxyethyl group or a cyclic ether group typified by tetrahydrobiranyl group, and tert butyl group. Tertiary alkyl groups, tertiary alkoxycarbonyl groups represented by tert-butoxycarbonyl groups, etc. are mainly used.

Patent Document 1: JP-A-4 211258

Disclosure of the invention

Problems to be solved by the invention [0004] In recent years, as the speed of miniaturization increases more and more, resist materials are required to have further improved resolution. However, it cannot be said that a positive resist composition using the conventional polyhydroxystyrene resin as described above has sufficient resolution and resist pattern shape.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a positive resist composition having excellent resolution and resist pattern shape.

Means for solving the problem

In order to achieve the above object, the present invention employs the following configuration.

The first aspect of the present invention is a positive resist composition comprising a resin component (A) whose alkali solubility is increased by the action of an acid and an acid generator component (B) that generates an acid upon exposure. The resin component (A) comprises a first structural unit (al) derived from hydroxystyrene force, a second structural unit (a2) derived from a (meth) acrylic acid ester having an alcoholic hydroxyl group, and The third structural unit (a3) in which the hydroxyl group of the structural unit derived from hydroxystyrene is protected with an acid dissociable, dissolution inhibiting group and / or a (meth) acrylic acid ester having an alcoholic hydroxyl group is induced. A first resin component (A1) having a fourth structural unit (a4) in which an alcoholic hydroxyl group of the structural unit is protected with an acid dissociable, dissolution inhibiting group, and a fifth structural unit (hydroxystyrene-force-induced) a5) and hydroxystyrene power A positive resist composition comprising a second resin component (A2) having a sixth structural unit (a6) in which a hydroxyl group of a derived structural unit is protected with an acid dissociable, dissolution inhibiting group It is.

The second aspect of the present invention includes a step of forming a resist film on a substrate using the positive resist composition of the first aspect, a step of exposing the resist film, an image of the resist film, and a resist It is a resist pattern formation method including the process of forming a pattern.

[0007] In the present specification, "(meth) acrylic acid" means one or both of methacrylic acid and acrylic acid. “Constituent unit” means a monomer unit constituting a polymer.

The invention's effect

[0008] According to the present invention, a positive resist composition excellent in resolution and resist pattern shape Is obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

The positive resist composition of the present invention has a resin component (A) having an acid dissociable, dissolution inhibiting group and increasing alkali solubility by the action of an acid (hereinafter sometimes referred to as component (A)). And an acid generator component (B) that generates an acid upon exposure (hereinafter also referred to as component (B)).

In the component (A), when the acid generated by the component (B) is acted upon by exposure, the acid dissociable, dissolution inhibiting group dissociates, thereby changing the entire component (A) from alkali-insoluble to alkali-soluble. To do.

Therefore, in the formation of a resist pattern, when exposed through a mask pattern, or when heated after exposure in addition to exposure, the exposed portion turns alkali-soluble while the unexposed portion remains alkali-insoluble, so alkali development By doing so, a positive resist pattern can be formed.

[0010] Ku resin component (A)>

In the present invention, the resin component (A) (hereinafter also referred to as component (A)) includes a first resin component (A1) and a second resin component (A2).

[0011] <First resin component (Al)>

The first resin component (A1) (hereinafter also referred to as component (A1)) comprises the following structural unit (al), structural unit (a2), structural unit (a3) and Z or (a4). Have.

(al): Hydroxystyrene power The first structural unit derived (hereinafter sometimes referred to as (al) unit)

(a2): (meth) acrylic acid ester having an alcoholic hydroxyl group Induced second structural unit (hereinafter sometimes referred to as (a2) unit)

(a3): Hydroxystyrene power Third structural unit in which the hydroxyl group of the derived structural unit is protected with an acid dissociable, dissolution inhibiting group (hereinafter sometimes referred to as (a3) unit)

(a4): a fourth constituent unit in which the constituent alcoholic hydroxyl group derived from a (meth) acrylic acid ester having an alcoholic hydroxyl group is protected with an acid dissociable, dissolution inhibiting group (hereinafter referred to as (a4) unit Sometimes it is.)

In addition to these (al) to (a4) units, the (A1) component is a 7th component that is further induced by styrene power. Structural unit (a7) (hereinafter also referred to as (a7) unit).

[0012] [First structural unit (al)]

The (al) unit is a structural unit derived from hydroxystyrene force and is represented by the following general formula (I). That is, the hydroxystyrene here is literally hydroxystyrene or

[0013]

(In the formula, R represents a hydrogen atom or a methyl group, and m represents an integer of:! To 3).

[0014] In the general formula (I), R is a hydrogen atom or a methyl group, and is preferably a hydrogen atom. m is preferably 1. The position of the hydroxyl group may be any of the o_, m- and p-positions, but the p-position is preferred because it is readily available and inexpensive.

[0015] In the component (A1), the proportion of the structural unit (al) is 2 with respect to all structural units constituting the component (A1).

It force preferably 0-80 Monore ^_0/0, preferably from force 30 to 70 Monore ^_0/0, the most it is 40 to 70 mol% is particularly preferred instrument 45 to 65 mol% preferable. Thereby, moderate alkali solubility can be obtained.

[0016] [Second structural unit (a2)]

The unit (a2) is a structural unit derived from a (meth) acrylic acid ester having an alcoholic hydroxyl group.

The first resin component (A1) has a strong structural unit (a2), so that a part of the hydroxyl group of polyhydroxystyrene is protected with an acid dissociable, dissolution inhibiting group (hereinafter referred to as PHS resin). In other words, the solubility in an alkaline developer is becoming lower.

That is, in the PHS resin, all units other than the unit protected with the acid dissociable, dissolution inhibiting group are structural units (hydroxystyrene unit) derived from hydroxystyrene force. The hydroxyl group of the droxystyrene unit is a phenolic hydroxyl group. On the other hand, the first resin component (A1) has, in addition to the hydroxystyrene unit (al), a structural unit (a2) having an alcoholic hydroxyl group that is inferior in alkali solubility to a phenolic hydroxyl group. Therefore, it is possible to reduce the solubility of the copolymer (A1) in an alkaline developer compared to PHS resin. As a result, it is possible to contribute to the reduction of diffetats and the improvement of resolution by lowering the protection rate.

The structural unit (a2) is not particularly limited as long as it is a structural unit derived from the (meth) acrylic acid ester force having an alcoholic hydroxyl group having such an action. In addition, because of its high resolution and excellent dry etching resistance, a structural unit that also induces an aliphatic polycyclic group-containing (meth) acrylate having an alcoholic hydroxyl group is preferred. .

Examples of the polycyclic group constituting the aliphatic polycyclic group having an alcoholic hydroxyl group include groups in which one hydrogen atom has been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Such a polycyclic group can be used by appropriately selecting from among many proposed ArF resists. Of these, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are industrially preferable.

As the structural unit (a2), in particular, a structural unit represented by the following general formula (II) and containing an adamantyl group-containing (meth) acrylate having at least one alcoholic hydroxyl group is derived. It can be used suitably.

Among the structural units (a2) represented by the following general formula (II), those most preferred are structural units represented by the following general formula (Ila).

[0019] [Chemical 2]

(In the formula, R is a hydrogen atom or a methyl group, and X is an integer of 1 to 3.)

[0020] (A1), the amount of the structural unit (a2) is, (A1) relative to the total structural units constituting the component 5-40 mole ^_0/0 preferably tool 5 to 30 mole ⁰ it is It is more preferably 10 to 25 mol%, and most preferably 10 to 20 mol%, more preferably / ₀ . As a result, the resolution is improved and the effect of reducing the differential is obtained.

[0021] [third structural unit (a3) and fourth structural unit (a4)]

The third structural unit (a3) is a structural unit in which the hydroxyl groups of the structural units similar to those listed as the first structural unit (al) are protected with an acid dissociable, dissolution inhibiting group. (A1) The hydroxystyrene skeletons in the first structural unit (al) and the third structural unit (a3) present in the component may be the same or different. Preferably they are the same.

The fourth structural unit (a4) has the same configuration as that given as the second structural unit (a2). This is a structural unit in which the alcoholic hydroxyl group of the unit is protected with an acid dissociable, dissolution inhibiting group. The (meth) acrylate skeleton in the second structural unit (a2) and the fourth structural unit (a4) present in the component (A1) may be the same or different. Preferably they are the same.

In component (A1), both (a3) unit and (a4) unit may be included, or only either one may be included, but (a3) unit only or ( Preferably it contains both a3) units and (a4) units.

[Acid dissociable, dissolution inhibiting group]

As the acid dissociable, dissolution inhibiting groups in the third structural unit (a3) and the fourth structural unit (a4), conventional chemically amplified KrF positive resist compositions and ArF positive resist compositions are used. In the product, those proposed as acid dissociable, dissolution inhibiting groups can be appropriately used. For example, tert-butyl group, tert-amyl group, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, etc. Group, cyclic ether group such as tetrahydrofuranyl group, 1 lower alkoxyalkyl group and the like can be used.

Among the 1 lower alkoxyalkyl groups, 1 lower alkoxyalkyl groups represented by the following general formula (III) are particularly preferable. Specific examples thereof include a linear or branched alkoxyalkyl group such as 1 ethoxyethyl group, 1 isopropoxychetyl group, 1-cyclohexyloxycetyl group, 1-adamantoxymethyl group, 2-a Cyclic alkoxyalkyl groups such as damantoxymethyl group, 1-adamantoxychetyl group, and 2-adamantoxychetyl group are listed. Among them, 1_ethoxyethyl Groups are preferred.

[0023] [Chemical 3]

(In the formula, R ¹ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, R ² represents a linear or branched alkyl group having 1 to 8 carbon atoms, or 5 to 5 carbon atoms) Represents a cycloalkyl group of 7)

[0024] The component (A1) includes, for example, a monomer corresponding to the structural unit (al) and a monomer corresponding to the structural unit (a2) such as azobisisobutyronitrile (AIBN), azobis (2 —After copolymerization by a conventional method such as a known radical polymerization method using a radical polymerization initiator such as methyl propionate, the hydroxyl groups of the structural unit (al) and / or the structural unit (a2) protected with acid dissociable, dissolution inhibiting group makes it possible to manufacture by a method of forming a structural unit (a3) and / or structural unit _(a 4).

Alternatively, a monomer corresponding to the structural unit (a3) is prepared in advance, the monomer and the monomer corresponding to the structural unit (a2) are copolymerized by a conventional method, and then hydrolyzed to obtain an acid of the structural unit (a3). A part of the dissociable, dissolution inhibiting group is changed to a hydroxyl group to form a structural unit (al), and if necessary, the hydroxyl group of the structural unit (a2) is protected with an acid dissociable, dissolution inhibiting group by a known method. It can also be produced by a method.

In the component (A1), the proportion of the structural unit (a3) is based on the total structural units constituting the component (A1)

5-50 that it can mol ⁰ / It is preferred tool 40 mol ^_0/0 ₀ is more preferred instrument 10 to 30 mol% are particularly preferred instrument 15 to 30 mol% Is most preferred.

In the component (A1), the proportion of the structural unit (a4), relative to the total structural units constituting the component (A1),: preferably be ~ 10 mol ^_0/0:! ~ 8 mol ^_0/0 More preferably:! ~ 6 mol% is particularly preferred:! ~ 5 mol% is most preferred.

Since it is excellent in the effect of this invention by setting it as the said range, it is preferable.

[0026] [Seventh structural unit (a7)]

The structural unit (a7) is a structural unit derived from styrene force, and is represented by the following general formula (IV). That is, styrene here means literally both styrene and monomethylstyrene.

[0027] [Chemical 4]

(In the formula, R is a hydrogen atom or a methyl group.)

[0028] In the first resin component (A1), the unit (a7) is not essential, but if it is contained, advantages such as improved depth of focus and improved dry etching resistance can be obtained.

In the case of containing (a7) units, the ratio of (a7) units in the first resin component (A1) is 0.5 to 10 of the total of all the structural units constituting the first resin component (A1). More preferably, it is 2 to 5 mol%. (A7) If the number of units exceeds the above range, the solubility in a developer tends to deteriorate.

[0029] The mass average molecular weight of the first resin component (A1) (polystyrene conversion by gel permeation chromatography, the same shall apply hereinafter) is preferably 3000 or more and 20000 or less, more preferably 5000 or more and 15000 or less. is there. When the mass average molecular weight is not more than the upper limit of the above range, the rectangularity of the resulting resist pattern is improved. In addition, generation of micro-bridges can be prevented. Further, when the mass average molecular weight is not less than the lower limit of the above range, etching resistance and heat resistance are good.

The micro-bridge here is a kind of development defect, for example, in a line and space pattern, a defect in which a portion close to the surface of an adjacent resist pattern is connected by a resist and is in a bridged state. Microbridges are more likely to occur at higher mass average molecular weights and at higher post-exposure heating (PEB) temperatures.

Further, it is preferable that the dispersity (MwZMn ratio) of the first resin component (A1) is monodisperse with low dispersibility because of excellent resolution. Specifically, it is 1-3, Preferably it is 1-2.

[0030] <Second resin component (A2)>

The second resin component (A2) (hereinafter also referred to as component (A2)) is composed of a fifth structural unit (a5) derived from hydroxystyrene and a hydroxyl group of the structural unit derived from hydroxystyrene force. And a sixth structural unit (a6) protected with an acid dissociable, dissolution inhibiting group. The fifth structural unit (a5) is the same as the first structural unit (al).

(A2), the amount of the structural unit (a5) is, (A2) to the total structural units constituting the component that force preferably 2 0-80 Monore ^_0/0, 30 to 80 Monore ^_0/0 More preferably, it is more preferably 40 to 80 mol%, and most preferably 50 to 80 mol%.

The sixth structural unit (a6) is the same as the third structural unit (a3). The hydroxystyrene skeletons in the fifth structural unit (a5) and the sixth structural unit (a6) present in the component (A2) may be the same or different. Preferably they are the same.

(A2), the amount of the structural unit (a6) is, (A2) to the total structural units constituting the component that force S preferably 5-50 Monore ^_0/0, at 10-45 Monore ^_0/0 more preferably lying force S, and most preferably 15 to 40 mole ^_0/0, which is it is particularly preferred instrument 20 to 40 mole ^_0/0.

The second resin component (A2) may contain other structural units other than the fifth structural unit (a5) and the sixth structural unit (a6) as long as the effects of the present invention are not impaired. It is preferable that the unit consists of the fifth structural unit (a5) and the sixth structural unit (a6).

In the present invention, the first resin component (A1) is not included in the second resin component (A2).

[0031] The second resin component (A2) can be obtained by protecting a part of the hydroxyl group of the polymer composed of the fifth structural unit (a5) with an acid dissociable, dissolution inhibiting group. Alternatively, the monomer corresponding to the fifth structural unit (a5) and the monomer corresponding to the sixth structural unit (a6) may be copolymerized by a known method.

[0032] In the second resin component (A2), the total power of the units (a5) and (a6) is preferably 50 mol% or more of the total of all the structural units constituting the (A2) component. Guyori is preferably 75 mol ^_0/0 or more, and most preferably 100 mole ^_0/0.

[0033] The mass average molecular weight of the second resin component (A2) is preferably 3000 or more and 30000 or less, more preferably 5000 or more and 25000 or less. When the mass average molecular weight is not more than the upper limit of the above range, the rectangularity of the resulting resist pattern is improved. In addition, the occurrence of microbridges can be prevented. Further, when the mass average molecular weight is not less than the lower limit of the above range, etching resistance and heat resistance are good.

The dispersity (Mw / Mn ratio) of the second resin component (A2) is a monodispersion with a low dispersity. When it exists, it is excellent in resolution and preferable. Specifically, it is 1-3, Preferably it is 1-2.

[0034] In the component (A), the mass ratio (A1) of the first resin component (A1) to the second resin component (A2):

(A2) is preferably 9 ::! To 1: 9, more preferably 9 ::! To 2: 8, particularly preferably 9 ::! To 4: 6, and most preferably 9 ::! To 7: 3 preferable. By setting it as the said range, it is excellent in the effect of this invention. In addition, the separation margin, LER (line edge roughness), and resist pattern shape are also good.

In addition to the first resin component (A1) and the second resin component (A2), the component (A) is used for positive resist compositions such as polyhydroxystyrene resin and (meth) acrylic resin. The ability to mix other resins as appropriate For the effect of the present invention, among the components (A) contained in the positive resist composition, the first resin component (A1) and the second resin component ( The total of A2) is preferably 80% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass.

[0035] <Acid generator component (B)>

The component (B) can be used without particular limitation from known acid generators used in conventional chemically amplified resist compositions.

Examples of such acid generators include onium salt acid generators such as odonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, There are various known diazomethane acid generators such as poly (bissulfonyl) diazomethanes, nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, and disulfone acid generators.

[0036] Specific examples of the onion salt-based acid generator include trifluoromethane sulfonate or nonafluorobutane sulfonate of difluoro rhododonium, trifluoromethane sulfonate or nonafluorobutane of bis (4_tert_butylphenol) Sulphonate, triphenylsulphonium trifluoromethanesulfonate, heptafluoropropane sulphonate or nonafluorobutane sulphonate, tri (4-methylphenol) snorephonium trifnoleolomethane sulphonate, hepta Funoleopropane sulphonate or its nonafluorobutane sulphonate, dimethyl (4-hydroxynaphtholenos) snorephonium trifunoleolomethane sulphonate, heptafunoleropropane Norre Phononate or its nonafluorobutane sulfonate, monophenyldimethylsulfurium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, diphenyl monomethyl sulfone trifluoromethane Sulfonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate, (4-methylphenyl) diphenyl sulphonium trifluoromethanesulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate, (4-methoxyphenol Nole) diphenyl sulfone trifluoromethane sulfonate, heptafluoropropane sulfonate or nonafrobutane sulfonate Tri (4-tert Buchinore) phenylalanine sulfo Niu beam of triflate Ruo Lome drawers sulfonates, its like hepta full O b propane sulfonate or a nona Full O Rob Tan sulfonates and the like.

Specific examples of oxime sulfonate-based acid generators include α- (ρ-toluenesulfonyloxyimino) -benzylcyanide,-(p-chlorobenzenebenzenesulfonyloxymino) -benzilcyanide, _α- (4- Nitrobenzenesulfonyloxymino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxymino) -benzylcyanide, α- (benzenesulfonyloxymino) -4- Black mouth benzyl cyanide, α- (benzenesulfonyloxymino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxymino) -2,6-dichlorobenzyl cyanide, H- (benzenesulfonyloxy) Simino) -4-methoxybenzyl cyanide, bis- (2-chlorobenzenesulfonyloxymino) -4-methoxybenzyl cyanide, bis- ( Benzenesulfonyloxymino) -Chen-2-ylacetonitrinole, a-(4-dodecylbenzenesulfonyloxymino) -benzylcyanide, H-[(p-tonole ensulfonyloxymino) -4-methoxyphenyl] acetonitrile, _a -[(dodecylbenzensulfonyloxyximino) -4-methoxyphenyl] acetonitrile, a- (tosyloxymino) -4-cenyllucyanide, bis- (methylsulfonyloxy) Simino)-1 -Cyclopentylacetonitrile, _a- (Methylsulfonyloxyimino)-1 -Cyclohexenylacetonitrile, H-(Methylsulfonyloxyimino)-1 -Cycloheptylacetonitrile , shed - (methylsulfonyl O key Consequences amino) - 1 - cyclopropyl OTA Saturation Rua Seto nitrile, _a - (triflate Ruo b methyl sulfo sulfonyl O key Consequences Mi ) - 1 - cyclopent two Ruasetonitoriru, _a - (triflate Ruo B methyl scan Norre Honi Ruo key Consequences amino) - hexyl § Seto nitrile cycloheteroalkyl, _alpha - (E chill sulfonyl O key Consequences amino) - E chill § Seto nitrile, _alpha - (propylsulfonyl O key Consequences amino) - propyl § Seto nits Lil, --(Cyclohexylsulfonyloxymino) -cyclopentylacetonitrile, a-(Cyclohexylsulfonyloxymino) -Cyclohexylacetonitrile, _a- (Cyclohexylsulfonyloxymino) -1 -Cyclopentenylacetonitrile, a-(Ethylsulfonyloxyimino)-1 -Cyclopentenylacetonitrile, _a- (Isopropylsulfonyloxymino)-1 -Cyclopentenylacetonitrile,-(n-Butylsulfonyloxyimino)- 1-cyclopentenylacetonitrile, a- (ethylsulfonyloxymino) -1-cyclo Xenylacetylonitrile, a- (isopropylsulfonyloxymino) -1-cyclohexenylacetonitrile, a- (n-butylsulfonyloxymino) -1-cyclohexenylacetonitrile, α (methylsulfonyloxy) Simino) phenylacetonitrile, α (methylsulfonyloxyimino) ρ methoxyphenylacetonitrile, a (trifluoromethylsulfonyloxymino) phenylacetonitrile, _a (trifluoromethylsulfonyloxymino) — p Metokishifue two Ruasetonitoriru, _a (E chill sulfonyl O Kishiimino) p Metokishifue two Ruasetonitoriru, like (propylsulfonyl O carboxymethyl Imi Roh) p Mechirufue two Ruasetonitoriru, a (methylsulfonyl O key Consequences amino) -p blanking opening Mofuwe two Ruasetonitoriru It is. Of these, α (methylsulfonyloxyimino) mono-methoxyphenylacetonitrile is preferred.

[0038] As the diazomethane-based PAG, any one of conventionally known ones can be appropriately selected for use, and in particular, from the viewpoint of transparency, appropriate acid strength, and alkali solubility. For example, bisalkyl or bisarylsulfonyldiazomethanes represented by the following general formula (V) are preferably used.

[0039] [Chemical 5]

In the formula (V), R ³ and R ⁴ each independently represents a branched or cyclic alkyl group or aryl group having 3 to 8 carbon atoms, preferably 4 to 7 carbon atoms. More specifically, examples of R ³ and R ⁴ include a tert_butyl group, a cyclohexyleno group, and a phenyl group. Among these, a cyclohexyl group is preferable because the rectangularity of the resulting resist pattern is further improved and the resolution is improved. A possible reason for this is that the cyclohexyl group is a bulky group, so that the generated acid is difficult to diffuse in the resist.

[0041] Specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfoninole) diazomethane, bis (ptoluenesulfonyl) diazomethane, and bis (1,1-dimethylethylsulfonyl). Examples thereof include diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like. Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane (in the case of A = 3), 1,4-bis ( Phenylsulfonyldiazomethylsulfonyl) butane (when A = 4), 1,6 bis (phenylsulfonyldiazomethylsulfonyl) hexane (when A = 6), 1,10 bis (phenylsulfonyl) Diazomethylsulfonyl) decane (when A = 10), 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane (when B = 2), 1,3-bis (cyclohexylsulfonyl) Diazomethylsulfonyl) propane (when B = 3), 1, 6 _bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane (when B = 6), 1, 10 _bis (cycloto Xylsulfonyldi Such zone methylsulfonyl) decane (B = 1 0) can be mentioned.

[0042] [Chemical 6]

[0043] As the component (B), one type of acid generator may be used alone, or two or more types may be used in combination.

In the present invention, the component (B) preferably contains a diazomethane acid generator and / or an onium salt acid generator. In particular, it is preferable to use a combination of at least one diazomethane acid generator and at least one onium salt acid generator in order to obtain good resolution and rectangularity.

The component (B) preferably contains 40 to 95% by mass of a diazomethane acid generator, more preferably 40 to 80% by mass, and still more preferably 40 to 70% by mass. Most preferably, it is 45-65 mass%. On the other hand, it is more preferable that the component (B) contains 5 to 60% by mass of an onium salt acid generator, more preferably 10 to 60% by mass, and further preferably 20 to 60% by mass. Most preferably, it is 30-60 mass%.

In the component (B), the total amount of the diazomethane acid generator and the onium salt acid generator may be 100% by mass, preferably 80% by mass or more.

[0044] The content of the component (B) in the resist composition is 0.5 to 30 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, the storage stability is improved. Further, the pattern can be sufficiently formed.

<0045> <Dissolution inhibitor (C)>

[0046] The positive resist composition of the present invention has at least one acid-dissociable, dissolution-inhibiting group as an optional component, and the dissolution-inhibiting group is dissociated by the action of an acid generated from the component (B). Add a dissolution inhibitor (C) that can generate acid.

As the powerful component (C), for example, a phenol derivative having a mass average molecular weight of 200 to 1000 and having 1 to 6 substituted or unsubstituted benzene nuclei is preferable. Specific examples include compounds represented by the following general formula (1).

[0047] [Chemical 7]

(In the formula, R ′ is an acid dissociable, dissolution inhibiting group.)

[0048] The acid dissociable, dissolution inhibiting group R 'can be arbitrarily selected from those known so far as chemically amplified positive resists. Specifically, tertiary alkyloxycarbonyl groups such as tert-butyloxycarbonyl group, tert-amyloxycarbonyl group; tert-butyloxycarbonylmethyl group, tert-butyloxycarbonyl group Tertiary alkyloxycarbonylalkyl group such as til group; Tertiary alkyl group such as tert-butyl group and tert-amyl group; Cyclic ether group such as tetrahydrobiranyl group and tetrahydrofuranyl group; Ethoxyethyl group, methoxy An alkoxyalkyl group such as a propyl group is preferable.

Of these, a tert-butyloxycarbonyl group, a tert-butyloxycarbonylmethyl group, a tert-butyl group, a tetrahydrobiranyl group, an ethoxyethyl group, a 1-methylcyclohexyl group, and a 1-ethylcyclohexyl group are preferable.

However, at least one acid dissociable, dissolution inhibiting group R ′ needs to use a carboxylic acid generating group such as a tertiary alkyloxycarbonylalkyl group.

The component (C) is usually used in the range of 0.:! To 50 parts by mass, preferably 1 to 20 parts by mass with respect to 100 parts by mass of the component (A).

[0049] <Nitrogen-containing compound (D)>

[0050] The positive resist composition of the present invention can further contain a nitrogen-containing organic compound (D) as an optional component in order to improve the resist pattern shape, stability over time, and the like. it can. Since a wide variety of component (D) has already been proposed, any known one can be used, but aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred. .

Aliphatic amines contain at least one hydrogen atom of ammonia NH and have 12 or more carbon atoms.

Three

Examples include amines substituted with alkyl groups or hydroxyalkyl groups below (alkylamines or alkylalcoholamines). Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; jetylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, Dialkylamines such as dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-ptyluamine, tri-n-octylamine Trialkylamines such as tri-nylamine, tri-n-decanylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, tri Alkyl alcohol § Min such as n- O click pentanol § Min and the like. Of these, alkyl alcoholamines are preferred, with alkyl alcoholamines and trialkylamines being preferred. Of the alkyl alcoholamines, triethanolamine is most preferably triisopropanolamine.

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).

<(E) component>

Further, for the purpose of preventing sensitivity deterioration due to the blending with the component (D) and improving the resist pattern shape, retention stability, etc., an organic carboxylic acid or phosphorus oxoacid or a derivative thereof is further included as an optional component. (E) (hereinafter referred to as component (E)) can be contained. In addition, the component (D) and the component (E) can be used in combination, or any of four types 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.

Phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid or derivatives such as esters thereof, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid. Phosphonic acids such as acid-di-n-butyl ester, phenylphosphonic acid, diphenylenoestenole phosphonate, dibenzenoleestenole phosphonate and derivatives thereof such as phosphinic acid, phosphinic acid such as phenylphosphinic acid And derivatives thereof such as esters thereof, among which phosphonic acid is particularly preferable.

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

[0052] <Other optional components>

The positive resist composition of the present invention may further contain miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, plasticizers, It is possible to add a stabilizer, a colorant, an antihalation agent, etc. as appropriate.

[0053] · Organic solvent (S)

The positive resist composition of the present invention is produced by dissolving the above-described component (A), component (B), and optionally component (C) and any of the components described later in an organic solvent. You can.

The component (A) is preferably prepared in advance by mixing the component (A1), the component (A2), and, if necessary, other resin components.

[0054] As the organic solvent, it is sufficient if each component to be used can be dissolved to form a uniform solution. Alternatively, two or more types can be appropriately selected and used.

For example, _ratatones such as Ί-buta-mouth rataton, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2_heptanone, ethylene glycol, ethylene glycolol monoacetate, diethylene glycolol, Diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, or monomethyl ether of dipropylene glycol monoacetate, Polyhydric alcohols such as monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, methyl lactate, ethyl lactate (EL), methyl acetate, acetic acid Examples thereof include esters such as ethyl, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate.

These organic solvents may be used alone or as a mixed solvent of two or more. 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. It is preferable to be within the range.

More specifically, when EL is blended 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 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.

Although the amount of the organic solvent used is not particularly limited, it is a concentration that can be applied to a substrate and the like, and is appropriately set according to the coating film thickness. Generally, the solid content concentration of the resist composition is 2 to 20 mass. %, Preferably 5 to 15% by mass.

The resist pattern can be formed as follows, for example.

First, the positive resist composition is applied onto a substrate such as silicon wafer with a spinner and the like, and subjected to a pre-beta for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. Form. Next, the resist film is selectively exposed with a KrF excimer laser beam through a desired mask pattern using, for example, a KrF exposure apparatus, and then subjected to PEB (post-exposure heating) at a temperature of 80 to 150 ° C. 40-: 120 seconds, preferably 60-90 seconds. Next, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethyl ammonium hydroxide. In this way, a resist pattern faithful to the mask pattern can be obtained. An organic or inorganic antireflection layer can be provided between the substrate and the coating layer of the resist composition.

[0056] The wavelength used for the exposure is not particularly limited, ArF excimer laser, KrF excimer laser, F excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam),

2

It can be performed using radiation such as X-rays and soft X-rays. In particular, the photoresist composition according to the present invention is effective for a KrF excimer laser.

In the present invention, it is possible to provide a positive resist composition and a resist pattern forming method capable of obtaining good resolution and resist pattern shape. Among the above-mentioned resolutions, the separation resolution (separate margin) is particularly excellent.

In addition, although the reason is not clear, the line edge roughness [(LER) unevenness of line side wall] is also excellent.

Example

[0058] A positive resist composition was prepared with the composition shown in Table 1 below. In Table 1, the numbers in [] indicate the amount (parts by mass).

[0059] [Table 1]

<Explanation of Abbreviations> (Al) —1: Resin composed of structural units represented by the following chemical formula.

[0061] [Chemical 8]

[Wherein, a: b: c: d (molar ratio) = 58: 17: 22: 3 (molar ratio), and Ev represents a 1_ethoxyethyl group. Mw = 12000, Mw / Mn = l.7]

[0062] (A2) -1: a resin comprising structural units represented by the following chemical formula.

[0063] [Chemical 9]

[Wherein, a: c (molar ratio) = 70: 30 (molar ratio), and Ev represents 1 ethoxyethyl group.

Mw = 20000, Mw / Mn = l.2]

[0064] PAGl: Triphenylsulfonyl nonafluorobutane sulfonate

PAG2: Bis (2,4-dimethylphenylsulfonyl) diazomethane

PAG3: Bis (cyclohexylsulfonyl) diazomethane

(D) _ 1: Triethanolamine

(D) _ 2: Triisopropanolamine

[0065] (C) -l: a dissolution inhibitor represented by the following chemical formula.

[Chemical 10]

[0066] ADD 1: Surfactant XR_ 104 (Dainippon Ink Chemical Co., Ltd.)

S 1: PGMEA / EL = 6Z4 mixed solvent

[0067] An organic antireflection film (product name: DUV-44, manufactured by Brew Science Co., Ltd., product name: DUV-44) was heated on an 8-inch silicon wafer at 225 ° C for 60 seconds to prepare a substrate having a thickness of 65 nm. The obtained positive resist composition was applied onto a substrate using a spinner, pre-betaed at 100 ° C. for 60 seconds on a hot plate, and dried to form a resist layer having a thickness of 270 nm.

Next, KrF excimer laser (248 nm) is selectively irradiated through a halftone mask with KrF scanner NSR- S 203B (Nikon, NA (numerical aperture) = 0.68, 2/3 ring illumination). did.

Then, 1 10 ° C, and PEB at 60 seconds conditions, further 2. developed for 60 seconds at 38 weight ^_0/0 tetramethylammonium Niu arm hydroxide aqueous solution at 23 ° C, then 15 seconds, the pure water Use water rinse. After performing shake-off drying, the film was dried by heating at 100 ° C. for 60 seconds to form a 1: 1 1: 1 130 nm line and space (L / S) pattern.

The following characteristics were evaluated. The results are summarized in Table 2.

[0068] · Evaluation method <LER>

For the 130 nmLZS pattern obtained above, 3 σ, which is a measure of LER, was obtained as an evaluation of the line edge roughness (LER) at which the surface of the side wall of the line pattern becomes uneven. 3 σ is the register of the sample using the side director SEM (trade name “S — 9220” manufactured by Hitachi, Ltd.). This is a triple value ( _3σ ) of the standard deviation ( _σ ) calculated from the results of measuring the width of the strike pattern at 32 locations. This 3σ means that the smaller the value, the smaller the roughness and the uniform width resist pattern was obtained.

In selective exposure, an exposure force smaller than Eop was started and the exposure time was gradually increased (exposure amount increased), and a pattern was formed for each exposure amount. Then, we observed with SEM which pattern the exposure was divided at, and Table 2 shows the “separate margin” calculated by the following formula. Larger values indicate better separation resolution.

“Separate Margin” (%) = 100— (Es / Eop X IOO)

Es: Sensitivity when pattern is separated (mj / cm ² ) (Energy)

Eop: Sensitivity when forming a 130 nmL / S pattern of 1: 1 (mj / _cm ² ) shape> The cross-sectional shape of the 130 nmLZS pattern obtained above was observed with a scanning electron microscope. As a result, those with good rectangularity were marked with ◯, and those with insufficient rectangularity were marked with X.

[0069] [Table 2]

[0070] From the results of the above examples:! To 3 and comparative examples:! To 2, the resolution and resist pattern can be obtained by using the components (A1) and (A2) together as the base resin of the resist composition. It was found to be excellent in shape. In addition, LER was excellent. Industrial applicability

The present invention can be applied to a positive resist yarn composition used in lithography technology and a resist pattern forming method using the same in the manufacture of semiconductor elements and liquid crystal display elements.

Claims

The scope of the claims

[1] A positive resist composition comprising a resin component (A) whose alkali solubility is increased by the action of an acid and an acid generator component (B) that generates an acid upon exposure,

The resin component (A) comprises a first structural unit (al) derived from hydroxystyrene force, a second structural unit (a2) derived from a (meth) acrylic acid ester having an alcoholic hydroxyl group, The third structural unit (a3) in which the hydroxyl group of the structural unit derived from hydroxystyrene force is protected with an acid dissociable, dissolution inhibiting group and / or the (meth) acrylic acid ester force having an alcoholic hydroxyl group A first resin component (A1) having a fourth structural unit (a4) in which the alcoholic hydroxyl group of the unit is protected with an acid dissociable, dissolution inhibiting group, and a fifth structural unit (a5 And a second resin component (A2) having a sixth structural unit (a6) in which the hydroxyl group of the structural unit derived from hydroxystyrene is protected with an acid dissociable, dissolution inhibiting group. A positive resist composition.

[2] The mass ratio of the first resin component (A1) to the second resin component (A2) is (A1): (A2) = 9:

The positive resist composition according to claim 1, wherein the ratio is 1: 9.

[3] The positive resist composition according to claim 1 or 2, wherein the acid generator component (B) includes a diazomethane acid generator and a Z or onium salt acid generator.

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

[5] The positive resist composition according to claim 1 or 2, further comprising a dissolution inhibitor (C).

[6] A step of forming a resist film on a substrate using the positive resist composition according to claim 1 or 2, a step of exposing the resist film, and developing the resist film to form a resist pattern. A resist pattern forming method including a process.