KR100864263B1 - Positive resist composition for thermal flow and method of forming pattern - Google Patents

Abstract

In the manufacture of a semiconductor device, a resist material which exhibits sufficient resolution even in normal pattern formation and can have a small pattern dimension only by an appropriate flow bake temperature, has a suitable flow rate, and has a rectangular profile with easy flow rate control to provide.

(a) An acid-decomposable resin which has increased solubility in an alkaline developer due to the action of an acid and (b) a photoacid generator, wherein the resin of (a) has the following glass transition points before and after acid decomposition. It consists of resin A and resin B which satisfy | fill the characteristic to display, It is a positive resist composition characterized by the above-mentioned.

Before acid decomposition: Glass transition point of Resin A> Glass transition point of Resin B

After acid decomposition: glass transition point of resin A <glass transition point of resin B

Description

Positive Resist Composition and Pattern Forming Method for Heat Flow {POSITIVE RESIST COMPOSITION FOR THERMAL FLOW AND METHOD OF FORMING PATTERN}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the relationship between glass transition points before and after acid degradability of resins A and B used in the present invention.

2 is a graph showing the relationship between the contact hole size (nm) and the flow bake temperature (° C.) for calculating the flow velocity and the optimum flow temperature.

Fig. 3 is a schematic diagram showing measurement points ΔL _L and ΔL _R in the resist for calculating the penetration amount as the evaluation of the hole shape after flow.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically amplified positive resist composition for semiconductor manufacturing, and more particularly, to a contact hole forming resist and a pattern forming method thereof in a chemically amplified positive resist for thermal flow.

The reduction projection exposure method by the light (g line | wire, i line | wire, KrF excimer laser beam) is used until now. In general, the resolution R of the lens is expressed by the following equation by Rayleigh's equation.                         

R = k [λ / (N.A.)]

Here, lambda is the exposure wavelength and NA is the numerical aperture of the lens, and NA = sinθ when the opening angle incident on the wafer is θ. k represents a value different depending on the resist, and is often used as a characteristic parameter indicating the performance of the resist. Experience with i-line resists can be as small as 0.5 even if the resists are improved. Increasing the resolution is to make R small, as is clear from the above equation, and for this purpose, it is necessary to increase NA, decrease λ, or decrease k. However, NA now increases to a value close to 0.7, and k reaches a limit of 0.5. In view of making the wavelength shorter, 193nm of ArF excimer laser light or 157nm of F ₂ excimer laser light are examined at 248nm of KrF excimer laser light, but the development of resist materials and devices that can be used in actual semiconductor manufacturing is delayed. There has been a demand for a resist material and a pattern forming method capable of forming a finer pattern with an exposure apparatus.

As a technique corresponding to the above method, the wafer is heated (flow baked) while irradiating ultraviolet (UV) in a vacuum disclosed in Japanese Patent Laid-Open No. 6-37071, and the resist shape is changed (flowed) to obtain a resist pattern. Although the method of adjusting the contact hole diameter of the semiconductor device capable of reducing the size is promising, development of a resist material suitable for this is insufficient. Moreover, since the process of fluid-baking a wafer while carrying out UV irradiation in vacuum is complicated, the resist material which obtains the same effect only by the fluid bake in vacuum was desired. However, when the flow bake process is applied to the resist material known so far, there existed a problem that it was difficult to control a hole size because of the high flow rate, or it did not flow enough even at a practical flow temperature (150 degrees C or less).

In addition, Japanese Patent Application Laid-Open No. 2000-137329 discloses a mixture of a polymer having a malonic acid ester group in the polymer backbone and a polymer which is thermally decomposed below the glass transition point of the polymer to increase intermolecular interactions. It was not a rectangle, and heat resistance was a problem.

An object of the present invention is to provide a resist composition exhibiting sufficient resolution and high heat resistance even by a conventional pattern forming method, and a resist material suitable for reducing the pattern dimension only with a fluidized bake and a pattern forming method thereof.

According to the present invention, a resist having sufficient resolving power and heat resistance even in normal pattern formation, and having a small pattern dimension with only an appropriate flow bake temperature, having a suitable flow rate, and having a rectangular profile to easily control the flow amount Material is provided.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the structural material of a positive chemical amplification resist composition, the present inventors discovered that the objective of this invention is achieved by using the material which has the following structure, and came to this invention.

That is, the said object is achieved by the following structures.                     

(1) At least the acid-decomposable resin which increases the solubility in alkaline developing solution by the action of (a) acid, and (b) the photo-acid generator, The resin of (a) is at the glass transition point before and after acid decomposition. The positive resist composition which consists of resin A and resin B which satisfy | fill the characteristic shown below.

Before acid decomposition: Glass transition point of Resin A> Glass transition point of Resin B

After acid decomposition: glass transition point of resin A <glass transition point of resin B

(2) The positive resist composition for heat flow of the structure of said (1).

(3) After forming a photoresist film on the semiconductor substrate with the positive resist composition of (1) above, pattern exposure, heat treatment, and development treatment are sequentially performed with radiation having a wavelength of 300 nm or less to form a slightly larger pattern than desired. And a pattern of a desired size by heating the semiconductor substrate at 120 to 160 占 폚 and thermally deforming the resist.

Hereinafter, each component used for this invention is demonstrated in detail.

[1] acid-decomposable resins

As a resin whose solubility in an alkaline developer is increased by the action of an acid, it is obtained by protecting an alkali-decomposable group possessed by the resin with an acid-decomposable group.

As alkali-soluble group, a phenolic hydroxyl group and a carboxylic acid group are preferable.

As a protecting group of an alkali-soluble group, an acetal group, a ketal group, an acetal ester group, t-butyl ester group, t-butoxycarbonyl group, etc. are preferable, and an alicyclic tertiary ester group etc. are also preferable. Among these, an acetal group and a t-butyl ester group are more preferable, and an acetal group is especially preferable from a viewpoint of the sensitivity, stability variation with respect to the standing time after exposure, and stability of dimensional variation (PED). Moreover, when an exposure light source is ArF, since absorption of a phenol skeleton is high, the t-butyl ester group, the acetal ester of a carboxyl group, etc. are preferable.

In particular, as the trunk polymer which introduces an acid-decomposable group suitable for KrF excimer laser and electron beam exposure, hydroxystyrenes are preferable, and acid-decomposable compounds such as hydroxystyrene and t-butyl acrylate or t-butyl methacrylate Copolymers of (meth) acrylates can be used. It is also possible to introduce non-acid-decomposable groups for the purpose of adjusting the alkali solubility of the trunk polymer. As an introduction method, the method by copolymerization with styrene, (meth) acrylic acid ester, and (meth) acrylic acid amide, or the method of protecting the hydroxyl group of hydroxystyrene with a non-acid-decomposable substituent is preferable. As the non-acid-decomposable substituent, an acetyl group, a mesyl group, a toluenesulfonyl group, an isopropoxy group, and the like are preferable, but not limited thereto.

In addition, coexistence of other acid-decomposable groups exhibiting different acid-decomposability such as t-butoxy group, t-butoxycarbonyloxy group, tetrahydropyranyloxy group, tetrahydrofuranyloxy group and the like in the same main chain may also be sensitive. It is desirable to be able to adjust the profile.

General formula (E) of an acid-decomposable resin suitable for preferable KrF excimer laser exposure and electron beam irradiation is shown below.

R ₃ 'each independently represent a hydrogen atom and a methyl group, and each of the plurality of R ₃ ' may be the same or different. R ₄ is a straight-chain, branched or cyclic C1-C12 alkyl group which may have a substituent, C6-C18 aromatic group which may have a substituent, or C7-C18 aralkyl which may have a substituent Display the flag.

Examples of the linear, branched or cyclic C1-C12 alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, cyclopropyl group, cyclopentyl group, 1-adamantylethyl group, etc. are mentioned.

The alkyl group as R ₄ may further have a substituent. Such substituents include cycloalkyl groups, aryloxy groups, which may contain halogen atoms such as hydroxyl groups, fluorine, chlorine, bromine and iodine, amino groups, nitro groups, cyano groups, carbonyl groups, ester groups, alkoxy groups, and heteroatoms; The substituent etc. which have a sulfonyl group are mentioned. Here, as the carbonyl group, an alkyl substituted carbonyl group (carbonyl group bonded to an alkyl group), an aromatic substituted carbonyl group (carbonyl group bonded to an aromatic group) are preferable, and as an ester group, an alkyl substituted ester group (ester group bonded to an alkyl group), aromatic substitution Preference is given to ester groups (ester groups bonded to aromatic groups). As an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, t-butoxy group, etc. are preferable. Examples of the cycloalkyl group include a cyclohexyl group, adamantyl group, cyclopentyl group, cyclopropyl group, and the like, and examples of containing heteroatoms include oxoranyl group and the like. A phenoxy group etc. are mentioned as an aryloxy group, You may have a substituent in this aryl group. Examples of the substituent having a sulfonyl group include alkylsulfonyl groups such as methylsulfonyl group and ethylsulfonyl group, and arylsulfonyl groups such as phenylsulfonyl group.

Examples of the aromatic group for R ₄ include groups derived from a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. In the cyclic | annular of these aromatic groups, what was described as a substituent which the alkyl group as R <_4> may hold can hold by a substituent.

Examples of the aralkyl group for R ₄ include benzyl group, phenethyl group, benzhydryl group, niphthylmethyl group and the like. These aralkyl groups can have what was described as a substituent which the alkyl group as R <_4> may hold by a substituent.

R ₅ is a hydrogen atom or a linear, branched alkyl group having 1 to 4 carbon atoms (eg, methyl group, ethyl group, propyl group, butyl group, sec-butyl group, t-butyl group, etc.), straight chain and branched carbon group having 1 to 4 carbon atoms Groups (e.g., methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, t-butoxy group, etc.), acetyloxy group, mesyloxy group, tosyloxy group, t- Butoxycarbonyloxy group, t-butoxycarbonylmethoxy group, tetrahydrofuranyloxy group or tetrahydropyranyloxy group, but t-butyl group, acetyl group, isopropoxy group, tetrahydrofuranyloxy group More preferred.

R ₆ is a hydrogen atom or an aromatic group which may have a linear, branched or cyclic C1-C8 alkyl group, a C6-C12 substituent, or an aralkyl group which may have a C7-C18 substituent, and is preferable. T-butyl group, 1-methylcyclohexyl group, and the like.

R ₇ and R ₈ each independently represent a hydrogen atom, a linear, branched or cyclic C 1-8 alkyl group, a C 6-12 aromatic group or an aralkyl group which may have a substituent having 7 to 18 carbon atoms. These may have a substituent.

Specific examples of the alkyl group, the aromatic group, and the aralkyl group as R ₆ to R ₈ may include those falling in the carbon number range in the specific examples of R ₄ .

In this invention, it is essential to mix 2 or more types of acid-decomposable resins, and it is necessary to satisfy specific relationship with respect to the glass transition temperature (Tg) of these 2 types of resin.

Each acid-decomposable resin has a glass transition temperature that varies depending on the molecular weight, molecular weight distribution, acid-decomposable protecting group and non-acid-decomposable group, the amount of introduction, and the copolymerization component.

In addition, the acid-decomposable resin decomposes and removes the protecting group by the action of an acid, thereby forming a phenolic hydroxyl group, a carboxyl group, or the like, and the glass transition temperature is increased.

In the present invention, in the two kinds of acid-decomposable resins A and B,

The glass transition point of Resin A before acid decomposition is Tg (A1),

The glass transition point of resin A after acid decomposition was Tg (A2),

The glass transition point of Resin B before acid decomposition was Tg (B1) and

If the glass transition point of resin B after acid decomposition is set to Tg (B2), it is necessary to satisfy Tg (A1)> Tg (B1) and Tg (A2) <Tg (B2) as shown in FIG. .

In order to make the glass transition point Tg (A2) after acid decomposition of resin A lower than the glass transition point Tg (B2) after acid decomposition of resin B, the molecular weight of precursor resin before introducing an acid-decomposable group is used, or Introduction of a non-acid-decomposable group, copolymerization of a monomer having a low glass transition point, and the like are effective. When introducing the same non-acid-decomposable group, it can also be set as the glass transition point lower than resin B by increasing the introduction amount. When the amount of introduction is the same, it is effective to use a group having a high Tg reducing effect such as long chain alkyl.

In order to make the glass transition point Tg (B1) before the acid decomposition of the resin B lower than the glass transition point (A1) before the acid decomposition of the resin A, the introduction amount of the acid-decomposable group is increased, or the acid-decomposable group to be introduced is long-chain alkyl group or bulky. It is effective to use acid-decomposable groups bearing substituents.

Synthesis of the resin can polymerize the monomer in the presence or in the form of a solvent by ordinary radical polymerization, anionic polymerization, cationic polymerization, or the like, and an acid-decomposable group can be introduced into the polymer reaction as necessary. It can also be obtained by copolymerizing a monomer having an acid-decomposable group alone or with another polymerizable monomer.

Moreover, it is preferable that Tg (A1) is 5-60 degreeC higher than Tg (B1), and it is more preferable that it is 10-50 degreeC high.

It is preferable that it is 10-70 degreeC higher than Tg (A1), and, as for Tg (A2), it is more preferable that it is 15-50 degreeC high.

It is preferable that Tg (B2) is 5-70 degreeC higher than Tg (A2), and it is more preferable that it is 10-50 degreeC high.

Tg can be measured using a scanning scanning calorimeter (DSC). After acid decomposition, Tg dissolves the acid-decomposable group polymer in a suitable solvent, adds an acid such as hydrochloric acid, sulfuric acid, paratoluenesulfonic acid, and heats in the presence of water to remove the protecting group and remove the solvent by water precipitation and the like. It can be obtained by solidification, powdering and drying. When introducing an acid-decomposable group in a polymer reaction, what is necessary is just to measure the Tg of the polymer before reaction.

The mixing ratio of the resin A and the resin B is generally 10:90 to 90:10 by weight ratio, preferably 20:80 to 80:20, and more preferably 30:70 to 70:30.

The acid-decomposable resin used in the present invention may contain other acid-decomposable resins other than the resins A and B, but the total amount of the resins A and B in the acid-decomposable resin is generally 10 to 100% by weight, preferably Preferably it is 30-100 weight%, More preferably, it is 50-100 weight%.

Specific examples of the resin are listed below, and the structure, composition, molecular weight, and glass transition point of the resin before and after acid decomposition are shown.

As a combination example of resin which concerns on this invention, P-5, P-4, P-18, P-21, P-6, P-14, P-2, P is mentioned about P-1 of the said Table 1, for example. -19, P-20, P-15, P-9, P-16, P-11, etc., P-18, P-21, P-6, P-14, P- for P-4 2, P-19, P-20, P-15, P-16, P-11, etc., P-5, P-1, P-4, P-18, P-21 for P-7 , P-6, P-14, P-2, P-19, P-20, P-15, P-9, P-16, P-12, P-11, etc. P-3, P-10, P-5, P-18, P-21, P-6, P-14, P-2, P-19, P-20, P-15, P-16, P- 11 and the like, P-3, P-10, P-5, P-18, P-21, P-6, P-14, P-2, P-19, P-20 for P-13 , P-16, P-11, etc., P-17, P-3, P-5, etc., P-9, P-16, P-11, etc., P-14 As for the combination with P-2, P-19, P-20, etc., each is a preferable combination.

The weight average molecular weight of each of the resins A and B is, as polystyrene equivalent molecular weight (Mw) by gel permeation chromatography (GPC), preferably 2,000 to 200,000, more preferably 4,000 to 50,000, more preferably 7,000 to 30,000. Particularly preferred. If the molecular weight exceeds 200,000, the solubility deteriorates and the resolution decreases. If the molecular weight is less than 2,000, the film loss tends to occur. In addition, a narrow (1.03 to 1.40) resin having a narrow molecular weight distribution (weight average molecular weight / number average molecular weight) is preferably used in view of resolution.

[2] photoacid generators

Compounds that generate an acid by irradiation of actinic rays or radiation used in the present invention (photoacid generators, including compounds that generate acids with electron beams) include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, and pigments. Known light used in photochromic agents, photochromic agents, microresists, and the like (ultraviolet rays of 400 to 200 nm, far ultraviolet rays, particularly preferably g rays, h rays, i rays, KrF excimer laser light), ArF excimer laser light, F ₂ the compounds and their mixtures capable of generating an acid by an excimer laser light, electron beam, X-ray, molecular beam or ion beam can be appropriately used by selection.

In addition, other photoacid generators used in the present invention include onium salts such as diazonium salts, ammonium, phosphonium salts, iodonium salts, sulfonium salts, selenium salts, arsonium salts, organic halogen compounds, and organometallic / Photo-degraded compounds that generate sulfonic acids, such as organohalides, photoacid generators having o-nitrobenzyl-type protecting groups, iminosulfonates, disulfone compounds, diazoketo sulfones, diazodisulfone compounds, etc. Can be.

Moreover, the compound which introduce | transduced the group or compound which generate | occur | produces an acid by these light in the main chain or side chain of resin can be used.

Furthermore, V.N.R.Pillai, Synthesis, (1), 1 (1980), A. Abab et al, Tetrahedron Lett., (47) 4555 (1971), D. H. R. Barton et al, J. Chem. Compounds which generate an acid by light described in Soc., (C), 329 (1970), US Pat. No. 3,779,778, EP 126,712 and the like can also be used.

Among the compounds generating the above-mentioned acids, those used particularly effectively will be described below.

(1) The oxazole derivative represented by the following general formula (PAG1) substituted with the trihalomethyl group, or the S-triazine derivative represented by general formula (PAG2).

In the formula, R ²⁰¹ represents a substituted or unsubstituted aryl group, alkenyl group, and R ²⁰² represents a substituted or unsubstituted aryl group, alkenyl group, alkyl group, or -C (Y) ₃ . Y represents a chlorine atom or a bromine atom.

Although the following compounds can be enumerated specifically, it is not limited to these.

(2) Iodonium salt represented by the following general formula (PAG3), or sulfonium salt represented by the general formula (PAG4).

Here, formulas Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represent a substituted or unsubstituted alkyl group and an aryl group.

Z ^- represents a pair anion, for example _{^{BF 4 -, AsF 6 -,}} PF 6 -, SbF 6 -, SiF 6 2-, ClO 4 -, CF 3 SO 3 - , such as perfluoro alkane sulfonic acid anion, Penta Condensed polynuclear aromatic sulfonic acid anions, anthraquinone sulfonic acid anions, sulfonic acid group-containing pigments and the like, such as a fluorobenzene sulfonic acid anion and a naphthalene-1-sulfonic acid anion, may be enumerated, but is not limited thereto.

In addition, two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ , and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

Specifically, the compound shown below is enumerated, but it is not limited to these.

In the above, Ph represents a phenyl group. The onium salts represented by the formulas (PAG3) and (PAG4) are known and can be synthesized, for example, by the methods described in US Pat. Nos. 2,807,648 and 4,247,473, Japanese Patent Application Laid-open No. 53-101,331.

(3) The disulfone derivative represented by the following general formula (PAG5) or the iminosulfonate derivative represented by the general formula (PAG6).

In the formula, Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group. R ²⁰⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, arylene group.

Although the compound shown below can be enumerated specifically, it is not limited to these.

(4) Diazodisulfone derivatives represented by the following general formula (PAG7).

R represents a straight chain, a branched or cyclic alkyl group, or the aryl group which may be substituted here.

Although the compound shown below is mentioned as a specific example, It is not limited to these.

Further, the photoacid generator described in Japanese Patent Application No. 2000-241457, Patent Application 2000-240060, Patent Application 2000-234733, Patent Application 2000-150217, Patent Application 2000-188077, and Patent Application 2000-62378 It can be used preferably.

The addition amount of these photo-acid generators is normally used in 0.1-30 weight% based on solid content in a composition, Preferably it is 0.3-20 weight%, More preferably, it is used in the range of 0.5-10 weight%. do.                     

If the amount of the photoacid generator is less than 0.1% by weight, the sensitivity tends to be lowered. If the amount of the photoacid generator is more than 30% by weight, the light absorption of the resist becomes excessively high, resulting in deterioration of the profile and narrow process (especially bake) margins. It is not desirable to lose.

[3] alkali-soluble resins

In the present invention, in the case of the KrF excimer laser and the electron beam exposure, an alkali-soluble resin which does not contain an acid-decomposable group in the positive resist composition can be used in addition to the acid-decomposable resin, whereby the sensitivity is improved.

Alkali-soluble resin which does not contain the said acid-decomposer (henceforth simply "alkali-soluble resin") is resin which is soluble in alkali, and can preferably mention polyhydroxy styrene, a novolak resin, and derivatives thereof. . Moreover, the copolymerization resin containing a p-hydroxy styrene unit can also be used if it is alkali-soluble. Among them, poly (p-hydroxy styrene), poly (p- / m-hydroxy styrene) copolymer, poly (p- / o-hydroxy styrene) copolymer, poly (p-hydroxy styrene / styrene) Copolymers are preferably used. In addition, various poly (alkyl substituted hydroxystyrene) resins of poly (4-hydroxy-3-methylstyrene), poly (4-hydroxy-3,5-dimethylstyrene), and a part of phenolic hydroxyl groups of the resin Alkylated or acetylated resins are also preferably used if they are alkali soluble.

Moreover, when a part (30 mol% or less of all phenol nucleus) of the said resin is hydrogenated, transparency of resin improves and it is preferable at the point of the sensitivity, the resolution, and the rectangular formation of a profile.

The weight average molecular weight of alkali-soluble resin is as polystyrene conversion molecular weight (Mw) by gel permeation chromatography (GPC), Preferably it is 2,000-200,000, 4,000-50,000 are more preferable, 7,000-30,000 are especially preferable. .

In this invention, as addition amount in the composition of alkali-soluble resin which does not contain the said acid-decomposable group, Preferably it is 2-60 weight% with respect to the total weight of solid content of a composition, More preferably, it is 5-30 weight% to be.

[4] acid-decomposable dissolution inhibiting compounds

In addition, in the present invention, an alkaline developer is decomposed by the action of an acid, which is decomposed by the action of an acid and introduced into a compound having a constant molecular weight for the alkaline developer and decomposed into an acid to a compound having a single structure. A low molecular weight compound having increased solubility in water is also preferably used.

The low molecular weight compound which is decomposed by the action of an acid and has increased solubility in an alkaline developer, preferably has an acid having a constant molecular weight of 3,000 or less and a group capable of decomposing into an acid in a compound having a single structure. It is a compound which is decomposed by the action of and becomes alkali-soluble.

Preferably, the compound has two or more groups that can be decomposed into an acid in the structure, and passes through eight or more bonding atoms excluding the acid-decomposable group at a position where the distance between the acid-decomposable groups is farthest. More preferably 10, even more preferably 12 compounds, or at least 3 acid-decomposable groups, and at the position where the distance between the acid-decomposable groups is farthest, 9 binding atoms excluding acid-decomposable groups The compound is preferably 10 or more, more preferably 11 or more. The upper limit of the number of the binding atoms is preferably 50, more preferably 30.

In the present invention, even when the acid-decomposable dissolution inhibiting compound has three or more acid-decomposable groups, preferably four or more, and also has two acid-decomposable groups, the acid-decomposable groups are at least a certain distance from each other. When it is separated from each other, the dissolution inhibiting property to the alkali-soluble resin is remarkably improved.

The acid-decomposable dissolution inhibiting compound may have a plurality of acid-decomposable groups on one benzene ring, but preferably a compound composed of a skeleton having one acid-decomposable group on one benzene ring. The molecular weight of the dissolution inhibiting compound is preferably 3000 or less, more preferably 500 to 3000, still more preferably 1000 to 2500.

Examples of the group that can be decomposed by an acid include a silyl ether group, cumyl ester group, acetal group, tetrahydropyranyl ether group, enol ether group, enol ester group, tertiary alkyl ether group and tertiary alkyl. Ester groups, tertiary alkyl carbonate groups and the like. More preferably, they are tertiary alkyl ester group, tertiary alkyl carbonate group, cumyl ester group, and tetrahydropyranyl ether group.

[5] organobasic compounds

The organobasic compound can be further added to the composition of the present invention.

Preferred organic basic compounds which can be used in the present invention are compounds which are more basic than phenol. Especially, a nitrogen containing basic compound is preferable. By adding an organic basic compound, the sensitivity change with time improves. As an organic basic compound, the compound which has a structure shown below is mentioned.

Where R ²⁵⁰ , R ²⁵¹ and R ²⁵² each independently represent a hydrogen atom, an alkyl group of 1 to 6 carbon atoms, an aminoalkyl group of 1 to 6 carbon atoms, a hydroxyalkyl group of 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group of 6 to 20 carbon atoms, Here, R ²⁵¹ and R ²⁵² may combine with each other to form a ring.

(Wherein R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represent an alkyl group having 1 to 6 carbon atoms)

More preferred compounds are nitrogen-containing basic compounds having at least two nitrogen atoms in different chemical environments in one molecule, particularly preferably compounds having both a substituted or unsubstituted amino group and a ring structure containing nitrogen atoms or It is a compound which has an alkylamino group. Preferred embodiments include substituted or unsubstituted guanidine, substituted or unsubstituted aminopyridine, substituted or unsubstituted aminoalkylpyridine, substituted or unsubstituted aminopyrrolidine, substituted or unsubstituted indazole, substituted or Unsubstituted pyrazole, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted purine, substituted or unsubstituted imidazoline, substituted or unsubstituted pyrazoline, substituted or unsubstituted Piperazine, substituted or unsubstituted aminomorpholine and substituted or unsubstituted aminoalkylmorpholine, and the like. Preferred substituents are amino group, aminoalkyl group, alkylamino group, aminoaryl group, arylamino group, alkyl group, alkoxy group, acyl group, acyloxy group, aryl group, aryloxy group, nitro group, hydroxyl group and cyano group.

As a preferred embodiment of the nitrogen-containing basic compound, dicyclohexylmethylamine, guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, 2-aminopyridine, 3-aminopyridine, 4-amino Pyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino -5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-amino Ethyl) -pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, Pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyridine Midine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine, 1,5-diazabicyclo [4.3.0] nona-5-ene, 1,8 Diazabicyclo [5.4.0] undeca-7-ene, 1,4-diazabicyclo [2.2.2] octane, 2,4,5-triphenylimidazole, N-methylmorpholine, N- Tertiary morpholine derivatives such as ethyl morpholine, N-hydroxyethyl morpholine, N-benzyl morpholine, cyclohexyl morpholinoethylthiourea (CHMETU), and interference amines described in JP-A-11-52575 ( For example, although the thing of the said publication can be mentioned, etc., It is not limited to this.

Particularly preferred embodiments are 1,5-diazabicyclo [4.3.0] nona-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, 1,4-diazabicyclo [2.2.2] octane, 4-dimethylaminopyridine, hexamethylenetetramine, 4,4-dimethylimidazoline, dicyclohexylmethylamine, pyrroles, pyrazoles, imidazoles, pyridazines, pyrimidines And tertiary morpholines such as CHMETU, and interfering amines such as bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate.

Especially, 1, 5- diazabicyclo [4.3.0] nona-5-ene, 1, 8- diazabicyclo [5.4.0] undeca-7-ene, and 1, 4- diazabicyclo [2.2. 2] octane, 4-dimethylaminopyridine, hexamethylenetetramine, CHMETU, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and dicyclohexylmethylamine are preferred.

These organobasic compounds are used individually or in combination of 2 or more types. The usage-amount of an organic basic compound is 0.001-10 weight% normally with respect to solid content of the whole composition of the photosensitive resin composition, Preferably it is 0.01-5 weight%. If it is less than 0.001 weight%, the said organic basic compound addition effect will not be acquired.

On the other hand, when it exceeds 10 weight%, there exists a tendency for the fall of a sensitivity or the developability of a non-exposed part to deteriorate.

[6] surfactants

In addition to the fluorine-type polymer which concerns on this invention, the positive photoresist composition of this invention may further contain another fluorine-type and / or silicone type surfactant.

The positive photoresist composition of the present invention may contain any one or two or more of a fluorine-based surfactant and / or a silicon-based surfactant and a surfactant containing both a fluorine atom and a silicon atom.

As these surfactants, for example, Japanese Patent Laid-Open No. 62-36663, Japanese Patent Laid-Open No. 61-226746, Japanese Patent Laid-Open No. 61-226745, Japanese Patent Laid-Open No. 62-170950, Japanese Patent Laid-Open No. 63-34540 Japanese Patent Application Laid-Open No. 7-230165, Japanese Patent Application Laid-Open No. 8-62834, Japanese Patent Application Laid-Open No. 9-54432, Japanese Patent Application Laid-Open No. 9-5988, US Pat. , Surfactants described in Nos. 5296330, 5436098, 5576143, 5294511, and 5824451 can be enumerated, and the following commercially available surfactants can be used as they are.

Commercially available surfactants that can be used include, for example, F-top EF301, EF303, (manufactured by Shin-Aki Takasei Co., Ltd.), fluoride FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), megapack F171, F173, F176, F189 (Dainippon Inky Kakaku Kogyo Co., Ltd.), Suplon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.) Fluorine-type surfactant or silicone type surfactant, such as these, can be mentioned. Moreover, polysiloxane polymer KP-341 (made by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicone type surfactant.

The compounding quantity of these surfactant is 0.001 weight%-2 weight% normally, based on solid content in the composition of this invention, Preferably they are 0.01 weight%-1 weight%. These surfactants may be added alone or in any combination.

As surfactants which can be used other than the above, specifically, polyoxyethylene alkyl ethers, such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, and poly Polyoxyethylene alkylallyl ethers such as oxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene-polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate Sorbitan fatty acid esters such as sorbitan monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan mono Stearate, Polyoxyethylene Sorbitan Trioleate And nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan tristearate and the like.

The compounding quantity of these other surfactant is 2 weight part or less normally per 100 weight part of solid content in the composition of this invention, Preferably it is 1 weight part or less.

[7] compounds that promote solubility in developing solutions

It may contain a compound having two or more phenolic OH groups that promote solubility in a developing solution. Examples of such compounds include polyhydroxy compounds, and preferred polyhydroxy compounds include phenols, resorucine, fluoroglucin, fluorogluside, 2,3,4-trihydroxybenzophenone, 2, 3,4,4'-tetrahydroxybenzophenone, α, α ', α "-tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, tris (4-hydroxyphenyl) methane , Tris (4-hydroxyphenyl) ethane, 1,1'-bis (4-hydroxyphenyl) cyclohexane.

The chemically amplified positive resist composition of the present invention is dissolved in a solvent for dissolving each of the above components and applied onto a support. Examples of the solvent that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, and 2-heptanone. γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetra Hydrofuran etc. are preferable and these solvents are used individually or in mixture.

In addition, high boiling point solvents such as N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and benzyl ethyl ether It can be mixed and used.

The chemically amplified positive resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) by a suitable coating method such as a spinner, a coater, and the like, and then exposed through a predetermined mask to be used in the manufacture of precision integrated circuit devices. By baking and developing, a favorable resist pattern can be obtained.

Examples of the developer of the chemically amplified positive resist composition of the present invention include first alkalis such as inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium phosphate, sodium metasilicate and aqueous ammonia, ethylamine, and n-propylamine. Second amines such as amines, diethylamine and di-n-butylamine, third amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, formamide and acetamide Amides, tetramethylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide, tetraethylammonium hydroxide, tributylmethylammonium hydroxide, tetraethanolammonium hydroxide, methyltriethanolammonium hydroxide Seed, benzyl methyl diethanol ammonium hydroxide, benzyl dimethyl ethanol ammonium hydroxide, benzyl triethanol ammonium hydroxide, tetrapropyl Aqueous solutions of alkalis such as quaternary ammonium salts such as ammonium hydroxide and tetrabutylammonium hydroxide, and cyclic amines such as pyrrole and piperidine.

Such a positive photoresist composition of the present invention is applied onto a substrate to form a thin film. As for the film thickness of this coating film, 0.2-1.2 micrometer is preferable. In the present invention, a commercially available inorganic or organic antireflection film can be used as necessary.

As the anti-reflection film, an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, α-silicon, etc., and an organic film type made of a light absorber and a polymer material can be used. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, a sputtering apparatus, etc. to form the film. Examples of the organic antireflection film include a condensation product of a diphenylamine derivative described in Japanese Patent Publication No. Hei 7-69611 and a formaldehyde-modified melamine resin, an alkali-soluble resin and a light absorber, and a maleic anhydride copolymer described in U.S. Patent 5,294,680. And a reactant of a diamine light absorber, a resin binder described in Japanese Patent Application Laid-Open No. 6-118631, and a methylolmelamine-based thermal crosslinking agent, a carboxylic acid group, an ethoxy group and a light absorber described in Patent Publication No. Hei 6-118656. An acrylic resin antireflection film contained in the same molecule, comprising a methylol melamine and a benzophenone light absorber described in Japanese Patent Application Laid-open No. Hei 8-87115, and a low molecular absorber in the polyvinyl alcohol resin described in Japanese Patent Application Laid-open No. Hei 8-179509 Addition etc. are mentioned.

In addition, as the organic antireflection film, DUV-30 series, DUV-40 series from Brewer Science Co., AC-2, AC-3 from Cypre Co., etc. can be used. .

The resist coating liquid is applied onto a substrate (e.g., silicon / silicon dioxide film) by a suitable coating method such as spinner, coater or the like so as to be used for the manufacture of the precision integrated circuit device. By exposing through a predetermined mask, baking and developing, a good resist pattern can be obtained.

Here, as exposure light, or radiation, preferably, optical or X-rays, electron beams having a wavelength of 150nm~250nm are listed, specifically, KrF excimer laser (248nm), ArF excimer laser (193nm), F ₂ Excimer laser (157 nm), X-rays, electron beams, and the like.

After the photoresist film is formed on the semiconductor substrate by the chemically amplified positive resist composition of the present invention, pattern exposure, heat treatment, and development treatment are sequentially performed with radiation having a wavelength of 300 nm or less, and after development, the diameter is about less than desired. A contact hole of a desired size can be obtained by forming a contact hole larger than 10 nm to 150 nm and heat-resisting the resist by heating the substrate at 120 ° C. to 160 ° C. for 30 seconds to 120 seconds. For example, a diameter of 80 nm can be obtained by heat flow from a diameter of 150 nm.

 Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to the following implementation.

[Examples 1-8 and Comparative Examples 1-6]

Each material shown in Table 2 was dissolved in 700 parts by weight of propylene glycol monoethyl ether acetate (PGMEA), and filtered through a 0.1 µm filter to prepare a resist solution.

Each resist solution obtained above was applied to a substrate on which a 60 nm film of DUV-44 (manufactured by Brewer Science, Inc.) was formed on a silicon wafer using a spin coater, and baked at 90 ° C. for 90 seconds to obtain a film thickness of 0.76 μm. A resist film was obtained.                     

In addition, the used photo-acid generator and nitrogen-containing basic compound are shown below. Resin is an acid-decomposable resin in Table 1.

The resist film was subjected to pattern exposure with a 248 nm KrF excimer laser stepper (NA = 0.55) through a 6% halftone mask. After exposure, heating was performed at 110 ° C. for 90 seconds, immediately developing for 60 seconds in an aqueous 0.26N tetramethylammonium hydroxide (TMAH) solution, and rinsing with water for 30 seconds to dry. The wafer thus obtained was treated for 90 seconds on a hot plate (flow baking treatment). At this time, the temperature of the hot plate at the time of a fluid bake process is called fluid bake temperature.

The pattern on the wafer which did not carry out the fluid baking process was observed with the scanning electron microscope, and the exposure amount which the part of the mask size of 240 nm (mask size) turns into 180 nm (1st target size) was made into the optimal exposure amount. In the optimum exposure amount, how the size of the first target size changes in accordance with the difference in the flow bake temperature was measured, and the optimum flow temperature (flow temperature resulting in a hole size of 130 nm) and the flow rate were evaluated from the graph of FIG. In addition, the shape of the cross section at the time when the first target size flowed at 130 nm was observed with a scanning electron microscope, the lengths of ΔL _L and ΔL _R shown in FIG. 2 were measured, and (ΔL _L + ΔL _R ) / 2 was computed as the penetration amount and it was set as evaluation of the shape of the hole after flow. The smaller the penetration, the better.

The evaluation results are shown in Table 3.

According to the present invention, it is possible to form a rectangular profile exhibiting sufficient resolution even in normal pattern formation, and to reduce the pattern dimension only by an appropriate flow bake temperature, to have a suitable flow bake speed, and to have a good shape after flow. It is possible to provide a resist material in which the flow amount is easily controlled.

Claims (3)

(a) an acid-decomposable resin whose solubility in an alkaline developer is increased by the action of an acid, and (b) a photoacid generator, Resin (a) consists of resin A and resin B which satisfy | fill the characteristic shown below about the glass transition point before and behind acid decomposition, The mixing ratio of the resin A and the resin B is 30:70 ~ 70:30 by weight ratio, the positive resist composition for heat flow. Before acid decomposition: Glass transition point of Resin A> Glass transition point of Resin B After acid decomposition: glass transition point of resin A <glass transition point of resin B delete After forming a photoresist film on the semiconductor substrate with the positive resist composition for heat flow according to claim 1, pattern exposure, heat treatment, and development treatment are sequentially performed with radiation having a wavelength of 300 nm or less to form a slightly larger pattern than desired. And a pattern of a desired size is formed by heating the semiconductor substrate at 120 to 160 占 폚 and thermally deforming the resist.

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