JP2012037867A - Positive resist material, and pattern formation method utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive resist material with a high sensitivity, a high resolution, a small line width roughness, and an excellent post-exposure pattern shape, especially a positive resist material using a high polymer suitable as a base resin of a chemical amplification positive resist material, and to provide a pattern formation method.SOLUTION: The positive resist material contains (as a base resin) a high polymer with the weight-average molecular weight 1,000-500,000 which at least contains a repeating unit a having a group represented by the following general formula (1), and a repeating unit b which is a carboxyl group with the hydrogen atom substituted by an acid labile group.

Description

  The present invention relates to a positive resist material, particularly a positive resist material using a polymer compound suitable as a base resin for a chemically amplified positive resist material, and a pattern forming method using the same.

  With the high integration and high speed of LSI, pattern rule miniaturization is progressing rapidly. In particular, the expansion of the flash memory market and the increase in storage capacity are leading to miniaturization. The fine line for miniaturization is mass production of 65 nm node devices by ArF lithography, and preparation for mass production of 45 nm nodes by next generation ArF immersion lithography is in progress. Furthermore, the next generation 32nm node includes immersion lithography using an ultra high NA lens that combines a liquid with a higher refractive index than water, a high refractive index lens, and a high refractive index resist film, and vacuum ultraviolet light (EUV) with a wavelength of 13.5nm. ) Lithography, double exposure of ArF lithography (double patterning lithography), etc. are candidates and are being studied.

Light elements such as hydrocarbons used in resist materials are hardly absorbed by high energy rays such as EB and X-rays, and polyhydroxystyrene-based resist materials are being studied.
In order to increase the accuracy of the line width in the mask manufacturing exposure apparatus, an exposure apparatus using an electron beam (EB) has been used from an exposure apparatus using a laser beam. Furthermore, since further miniaturization is possible by increasing the acceleration voltage in the electron gun of EB, 10 keV to 30 keV, and recently 50 keV is the mainstream, and studies of 100 keV are also underway.

  Here, as the acceleration voltage increases, lowering the sensitivity of the resist film has become a problem. When the acceleration voltage is improved, the influence of forward scattering in the resist film is reduced, so that the contrast of the electron drawing energy is improved and the resolution and dimensional controllability are improved. Since it passes, the sensitivity of the resist film decreases. Since the mask exposure machine exposes by direct drawing with a single stroke, a decrease in sensitivity of the resist film leads to a decrease in productivity, which is not preferable. In view of the demand for higher sensitivity, chemically amplified resist materials are being studied.

  Further, with the progress of miniaturization, image blur due to acid diffusion has become a problem. In order to ensure the resolution in a fine pattern with a size size of 45 nm or more, it is proposed that not only the conventionally proposed improvement in dissolution contrast but also the control of acid diffusion is important (for example, non-patent) Reference 1 etc.). However, chemically amplified resist materials have increased sensitivity and contrast due to acid diffusion. Therefore, reducing the post-exposure bake temperature (PEB) temperature and time to limit acid diffusion results in sensitivity and contrast. It drops significantly.

  Non-Patent Document 2 shows a relationship between sensitivity, resolution, and roughness triangle trade-off. Here, it is necessary to suppress acid diffusion in order to expand the exposure margin, but it has been reported that the roughness deteriorates rapidly when the acid diffusion distance is 50 nm or less.

  It is effective to suppress acid diffusion by adding an acid generator that generates a bulky acid. Therefore, it has been proposed to copolymerize an onium salt acid generator having a polymerizable olefin in the polymer. For example, Patent Document 1 proposes a sulfonium salt and an iodonium salt having a polymerizable olefin that generates a specific sulfonic acid. For example, Patent Document 2 proposes a sulfonium salt in which sulfonic acid is directly bonded to the main chain.

  The trade-off relationship between sensitivity and roughness is also shown. For example, Non-Patent Document 3 shows the inverse relationship between sensitivity and roughness, and it is predicted that the roughness of the resist film will be reduced by reducing shot noise due to increased exposure. ing. In Non-Patent Document 4, a resist film with an increased amount of quencher is effective in reducing the roughness, but at the same time the sensitivity deteriorates, so there is a trade-off relationship between the sensitivity of the EUV and the roughness. There is a need to increase the generation quantum efficiency.

  Non-Patent Document 5 proposes a mechanism in which electrons move to the PAG due to polymer excitation by exposure and acid is released as an acid generation mechanism in electron beam exposure. Both EB and EUV are higher than the ionization potential energy threshold of 10 eV, and it is estimated that the base polymer is easily ionized. Hydroxystyrene is shown as a material that promotes electron transfer.

  Non-Patent Document 6 shows that poly-4-hydroxystyrene has higher acid generation efficiency in EB exposure than poly-4-methoxystyrene, and poly-4-hydroxystyrene is efficiently transferred to PAG by irradiation with EB. It is suggested to move.

Therefore, non-patented material is a copolymer of hydroxystyrene to increase acid generation efficiency by electron transfer, PAG methacrylate in which sulfonic acid is directly linked to the polymer main chain to suppress acid diffusion, and methacrylate having acid labile groups. It is proposed in Document 7.
Since hydroxystyrene has a weakly acidic phenolic hydroxyl group, it has an effect of reducing swelling in an alkaline developer, but increases acid diffusion. On the other hand, methacrylate containing lactone as an adhesive group, which is widely used for ArF resist, has high hydrophilicity and has no effect of reducing swelling due to lack of alkali solubility, but suppresses acid diffusion. it can. It is possible to balance sensitivity improvement, swelling reduction and acid diffusion control by combining hydroxystyrene and methacrylate having a lactone ring as an adhesive group, but it is still not sufficient.

JP 2006-045311 A JP 2006-178317 A

SPIE Vol. 6520 65203L-1 (2007) SPIE Vol. 5753 p269 (2005) SPIE Vol. 3331 p531 (1998) SPIE Vol. 5374 p74 (2004) SPIE Vol. 5753 p361 (2005) SPIE Vol. 5753 p1034 (2005) SPIE Vol. 6519 p6519F1-1 (2007)

  The present invention has been made in view of the above circumstances, and has a higher sensitivity, higher resolution, lower roughness (LWR), and better pattern shape after exposure, in particular chemicals, higher than conventional positive resist materials. An object of the present invention is to provide a positive resist material using a polymer compound suitable as a base resin of an amplified positive resist material, and a pattern forming method.

In order to solve the above problems, the present invention includes at least a repeating unit a having a group represented by the following general formula (1) and a repeating unit b in which a hydrogen atom of a carboxyl group is substituted with an acid labile group. A positive resist material comprising a polymer compound having a weight average molecular weight of 1,000 to 500,000 as a base resin is provided.

（式中、Ｒ^１は水素原子又はメチル基である。ａは０＜ａ＜１．０の範囲である。） In this case, it is preferable that the repeating unit a is represented by the following general formula (2).

(In the formula, R ¹ is a hydrogen atom or a methyl group. A is in the range of 0 <a <1.0.)

（式中、Ｒ^２は水素原子又はメチル基、Ｒ^３は酸不安定基を表す。Ｘは単結合、エステル基、ラクトン環を有する炭素数１〜１２の連結基、フェニレン基、又はナフチレン基である。ｂは０＜ｂ＜１．０の範囲である。） In this case, the repeating unit b is preferably one represented by the following general formula (3).

(Wherein R ² represents a hydrogen atom or a methyl group, and R ³ represents an acid labile group. X represents a single bond, an ester group, a linking group having 1 to 12 carbon atoms having a lactone ring, a phenylene group, or a naphthylene group. B is in the range of 0 <b <1.0.)

  Thus, the repeating unit a having the group represented by the general formula (1), particularly the repeating unit a represented by the general formula (2), and the hydrogen atom of the carboxyl group are substituted with an acid labile group. The positive resist of the present invention containing, as a base resin, a high molecular compound having a weight average molecular weight of 1,000 to 500,000, including the repeating unit b, particularly the repeating unit b represented by the general formula (3). If the material is used, the alkali dissolution rate contrast before and after exposure is significantly high, and in addition, the acid diffusion rate can be suppressed, so that it has high resolution, high sensitivity, low roughness (LWR), and a pattern after exposure. Good shape.

  In addition to the repeating unit a and the repeating unit b, a repeating unit c having an adhesive group selected from a hydroxyl group, a lactone ring, an ether group, an ester group, a carbonyl group, and a cyano group was further copolymerized. A polymer compound (where 0 <a <1.0, 0 <b <1.0, 0 <c ≦ 0.9, 0.2 ≦ a + b + c ≦ 1.0) is contained as a base resin. It is preferable.

  Thus, if the polymer compound contained as the base resin of the positive resist contains the repeating unit c having an adhesive group in addition to the repeating unit a and the repeating unit b, the adhesion is further improved. be able to.

The positive resist material is preferably a chemically amplified positive resist material.
The positive resist material of the present invention containing the polymer compound is converted so that, for example, the acid labile group of the repeating unit b is eliminated by the acid generated from the acid generator, and the resist exposed portion is dissolved in the developer. Thus, a chemically amplified positive resist material capable of obtaining a highly accurate pattern can be obtained.

  The positive resist material may contain any one or more of an organic solvent, an acid generator, a dissolution controller, a basic compound, and a surfactant.

  Thus, by mix | blending an organic solvent, the applicability | paintability to the board | substrate etc. of a resist material can be improved, for example. Further, by adding an acid generator, it can be made more sensitive. Moreover, by mix | blending a dissolution control agent, the difference of the dissolution rate of an exposed part and an unexposed part can be enlarged further, and the resolution can be improved further. By compounding the basic compound, the acid diffusion rate in the resist film can be suppressed, and the resolution can be further improved. Furthermore, the application | coating property of a resist material can further be improved or controlled by mix | blending surfactant.

  Such a positive resist material of the present invention includes at least a step of applying the positive resist material on a substrate, a step of exposing to high energy rays after heat treatment, and a step of developing using a developer. Can be used as a method for forming a pattern on a semiconductor substrate, a mask substrate, or the like.

  Needless to say, in the pattern forming method of the present invention, development may be performed after the post-exposure heat treatment, and various other processes such as an etching process, a resist removal process, and a cleaning process may be performed. Yes.

In this case, an electron beam or soft X-ray in the wavelength range of 3 to 15 nm can be used as a light source in the step of exposing with the high energy beam.
Thus, the positive resist material of the present invention can be particularly suitably used for forming a fine pattern using an electron beam or soft X-ray having a wavelength of 3 to 15 nm as a light source.

As described above, the positive resist material of the present invention has a significantly high alkali dissolution rate contrast before and after exposure, and in particular, it can suppress the acid diffusion rate and thus has high resolution, high sensitivity, and exposure. The later pattern shape and roughness are good. Therefore, a positive resist material, particularly a chemically amplified positive resist material, which is particularly suitable as a fine pattern forming material for VLSI manufacturing or photomask fine pattern formation, EB, EUV, and ArF excimer laser exposure can be obtained. .
The positive resist material of the present invention, particularly the chemically amplified positive resist material, is used not only for lithography in semiconductor circuit formation, but also for mask circuit pattern formation, micromachines, thin film magnetic heads, etc. It can also be applied to circuit formation.
Fluorescein is also known as a phosphorescent substance. Irradiation with an Ar laser with a wavelength of 488 nm or the like generates green light with a wavelength of 521 nm. Since the polymer compound contained in the resist material of the present invention as the base resin contains fluorescein as a repeating unit, the resist film portion emits light by irradiating the patterned resist film with light, and the resist pattern shines. Can do. If a fluorescence microscope is used, the resist pattern can be observed with high luminance, and position detection can be performed using the resist pattern.

Hereinafter, the present invention will be described in more detail.
As described above, with the high integration and high speed of LSI, the pattern rule has been miniaturized, and while maintaining high resolution, high sensitivity, low roughness (LWR), and pattern shape Also, a good positive resist material has been demanded.

  The inventors of the present invention have made extensive studies to obtain a positive resist material having high resolution, high sensitivity, low roughness (LWR), and good pattern shape, which has recently been requested in recent years. It has been found that it is extremely effective to use a polymer containing the repeating unit as a base resin of a positive resist material, particularly a chemically amplified positive resist material, and the present invention has been completed.

  More specifically, the present inventors have found that the repeating unit having both a phenolic hydroxyl group and a lactone ring in the molecule and the hydrogen atom of the carboxyl group has an acid non-reactive property in order to suppress acid diffusion and improve dissolution contrast. By using a polymer obtained by copolymerization with a repeating unit substituted with a stable group as a base resin for a positive resist material, particularly a chemically amplified positive resist material, the alkali dissolution rate contrast before and after exposure is significantly high. Highly effective in suppressing acid diffusion, high resolution, high sensitivity, good pattern shape and roughness (LWR) after exposure, especially as a fine pattern forming material for VLSI manufacturing or photomasks As a result of finding out that a suitable positive resist material, particularly a chemically amplified positive resist material can be obtained, the present invention has been completed. That.

That is, the positive resist of the present invention includes at least a repeating unit a having a group represented by the following general formula (1) and a repeating unit b in which a hydrogen atom of a carboxyl group is substituted with an acid labile group. A positive resist material comprising a polymer compound having a weight average molecular weight of 1,000 to 500,000 as a base resin.

Fluorescein has a sensitizing effect on EB and EUV, and has a function of preventing swelling in an alkaline developer and a lactone ring of an adhesive group having an acid diffusion inhibiting effect in the same molecule, so that it has multiple functions. It can be held in the same molecule.
In addition, since fluorescein has a quaternary carbon cardo structure, free rotation in the molecule is constrained and the effect of suppressing acid diffusion is high.

  The positive resist material of the present invention has a repeating unit having such a phenol and lactone ring in the same molecule in a polymer compound serving as a base resin, that is, a repeating unit having a group represented by the general formula (1). Since it contains a, the effect of suppressing acid diffusion, the dissolution contrast of the resist film is high, the resolution is high, the swelling prevention effect, the exposure margin, the pattern shape and roughness (LWR after exposure) ) Is good. In addition, excellent adhesion and alkali solubility, particularly a sensitization effect in EUV or EB exposure can be exhibited. Therefore, since it has these excellent characteristics, it is very practical and is very effective as a resist material mask pattern forming material for VLSI.

（式中、Ｒ^１は水素原子又はメチル基である。ａは０＜ａ＜１．０の範囲である。） The repeating unit a having the group represented by the general formula (1) is preferably (meth) acrylic acid (in the present specification, “(meth) acrylic acid” means one of acrylic acid and methacrylic acid). Or a hydrogen atom of a carboxyl group) (which means both), and can be represented by the following general formula (2).

(In the formula, R ¹ is a hydrogen atom or a methyl group. A is in the range of 0 <a <1.0.)

（式中、Ｒ^２は水素原子又はメチル基、Ｒ^３は酸不安定基を表す。Ｘは単結合、エステル基、ラクトン環を有する炭素数１〜１２の連結基、フェニレン基、又はナフチレン基である。ｂは０＜ｂ＜１．０の範囲である。） Moreover, the repeating unit b can particularly preferably include those represented by the following general formula (3).

(Wherein R ² represents a hydrogen atom or a methyl group, and R ³ represents an acid labile group. X represents a single bond, an ester group, a linking group having 1 to 12 carbon atoms having a lactone ring, a phenylene group, or a naphthylene group. B is in the range of 0 <b <1.0.)

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｘは前述と同様である。ａは０＜ａ＜１．０、ｂは０＜ｂ＜１．０、ａ＋ｂは０．１≦ａ＋ｂ≦１．０の範囲である。） In this case, as the base resin contained in the positive resist material of the present invention, the repeating unit a represented by the general formula (2) and the repeating unit b represented by the general formula (3) are copolymerized. The polymer compound represented by the following general formula (4) is particularly preferable.

(Wherein R ¹ , R ² , R ³ and X are the same as described above. A is 0 <a <1.0, b is 0 <b <1.0, and a + b is 0.1 ≦ a + b ≦ 1. .0 range.)

（式中、Ｒ^１は前述と同様である。） Specific examples of the monomer for obtaining the repeating unit a represented by the general formula (2) can be given below.

(Wherein R ¹ is the same as described above.)

  This monomer can be synthesized by making one of the two hydroxyl groups of fluorescein a methacrylate ester.

（式中、Ｒ^２、Ｒ^３、Ｘは前述の通りである。） Examples of the monomer for obtaining the repeating unit b having an acid labile group represented by the general formula (3) can be shown below.

(Wherein R ² , R ³ and X are as described above.)

In this case, examples of the linking group having 1 to 12 carbon atoms having a lactone ring of X include the following.

The acid labile group of R ^{3 in} the general formula (3) is variously selected, and may be the same or different, and particularly, groups substituted by the following formulas (A-1) to (A-3) The thing shown by these is mentioned preferably.

In the above formula (A-1), R ³⁰ is a tertiary alkyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, each alkyl group is a trialkylsilyl group having 1 to 6 carbon atoms, and 4 to 20 carbon atoms. Or a group represented by the above formula (A-3). Specific examples of the tertiary alkyl group include a tert-butyl group, a tert-amyl group, a 1,1-diethylpropyl group, and 1-ethyl. Cyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, 2-methyl-2-adamantyl group, etc. Specific examples of the trialkylsilyl group include trimethylsilyl group, triethylsilyl group, dimethyl-tert-butylsilyl group, and the like. Specific examples of the oxoalkyl group include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, and a 5-methyl-2-oxooxolan-5-yl group. a1 is an integer of 0-6.

  Specific examples of the acid labile group of the above formula (A-1) include tert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, tert-amyloxycarbonyl group, tert-amyloxycarbonylmethyl group, 1,1 -Diethylpropyloxycarbonyl group, 1,1-diethylpropyloxycarbonylmethyl group, 1-ethylcyclopentyloxycarbonyl group, 1-ethylcyclopentyloxycarbonylmethyl group, 1-ethyl-2-cyclopentenyloxycarbonyl group, 1-ethyl Examples include 2-cyclopentenyloxycarbonylmethyl group, 1-ethoxyethoxycarbonylmethyl group, 2-tetrahydropyranyloxycarbonylmethyl group, 2-tetrahydrofuranyloxycarbonylmethyl group and the like.

Furthermore, the substituent shown by following formula (A-1) -1-(A-1) -10 can also be mentioned.

In the above formulas (A-1) -1 to (A-1) -10, R ³⁷ is the same or different from each other, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or 6 carbon atoms. 20 aryl ^{group, R 38} is a hydrogen atom, or a straight, a branched, or cyclic alkyl group.
R ³⁹ is a linear, branched or cyclic alkyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, which are the same or different from each other.
a1 is as described above.

Next, in the above formula (A-2), R ³¹ and R ³² are each independently a hydrogen atom, or a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. Specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, cyclopentyl group, cyclohexyl group, 2-ethylhexyl group, n-octyl group, etc. Can be illustrated.
R ³³ represents a monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may have a hetero atom such as an oxygen atom. For example, a linear, branched or cyclic alkyl group Or a group in which a part of these hydrogen atoms is substituted with a hydroxyl group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Specific examples include the following substituted alkyl groups. .

R ³¹ and R ³² , R ³¹ and R ³³ , R ³² and R ³³ may be combined to form a ring together with the carbon atom to which they are bonded, and in forming a ring, it is involved in the formation of the ring R ³¹ , R ³² and R ³³ each represent a linear or branched alkylene group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and preferably the ring has 3 to 10 carbon atoms, particularly 4 to 10 carbon atoms. is there.

  Of the acid labile groups represented by the above formula (A-2), examples of the linear or branched groups include those of the following formulas (A-2) -1 to (A-2) -35. be able to.

  Among the acid labile groups represented by the above formula (A-2), the cyclic ones include tetrahydrofuran-2-yl group, 2-methyltetrahydrofuran-2-yl group, tetrahydropyran-2-yl group, 2- Examples thereof include a methyltetrahydropyran-2-yl group.

  In addition, the base resin may be intermolecularly or intramolecularly crosslinked by an acid labile group represented by the following formula (A-2a) or (A-2b).

In the formulas (A-2a) and (A-2b), R ⁴⁰ and R ⁴¹ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. Alternatively, R ⁴⁰ and R ⁴¹ may combine to form a ring together with the carbon atom to which they are bonded, and when forming a ring, R ⁴⁰ and R ⁴¹ are linear or branched having 1 to 8 carbon atoms. -Like alkylene group. R ⁴² is a straight-chain having 1 to 10 carbon atoms, branched or cyclic alkylene group, b1, d1 are each independently 0 or 1 to 10, preferably 0 or an integer of 1 to 5, c1 is 1-7 Is an integer. A represents a (c1 + 1) -valent aliphatic or alicyclic saturated hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group having 1 to 50 carbon atoms, and these groups may intervene with a hetero atom. Or a part of hydrogen atoms bonded to the carbon atom may be substituted with a hydroxyl group, a carboxyl group, a carbonyl group or a fluorine atom. B represents —CO—O—, —NHCO—O— or —NHCONH—.

  In this case, preferably, A is a divalent to tetravalent C1-20 linear, branched or cyclic alkylene group, an alkyltriyl group, an alkyltetrayl group, or an arylene group having 6 to 30 carbon atoms. In these groups, a hetero atom may be interposed, and a part of hydrogen atoms bonded to the carbon atom may be substituted with a hydroxyl group, a carboxyl group, an acyl group, or a halogen atom. C1 is preferably an integer of 1 to 3.

  Specific examples of the crosslinked acetal groups represented by the above formulas (A-2a) and (A-2b) include those represented by the following formulas (A-2) -36 to (A-2) -43.

Next, in the above formula (A-3), R ³⁴ , R ³⁵ , and R ³⁶ are each independently a monovalent hydrocarbon group such as a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms. Or a linear, branched or cyclic alkenyl group having 2 to 20 carbon atoms, which may contain heteroatoms such as oxygen, sulfur, nitrogen and fluorine, and R ³⁴ and R ³⁵ , R ³⁴ and R ³⁶ , R ³⁵ and R ³⁶ may be bonded together to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

  The tertiary alkyl group represented by the above formula (A-3) includes a tert-butyl group, a triethylcarbyl group, a 1-ethylnorbornyl group, a 1-methylcyclohexyl group, a 1-ethylcyclopentyl group, 2- (2 -Methyl) adamantyl group, 2- (2-ethyl) adamantyl group, tert-amyl group and the like.

Moreover, as a tertiary alkyl group, the formula (A-3) -1-(A-3) -18 shown below can also be specifically mentioned.

In the above formulas (A-3) -1 to (A-3) -18, R ⁴³ is the same or different, linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, or 6 to 6 carbon atoms. An aryl group such as 20 phenyl groups is shown. R ⁴⁴ and R ⁴⁶ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. R ⁴⁵ represents an aryl group such as a phenyl group having 6 to 20 carbon atoms.

Further, as shown in the following formulas (A-3) -19 and (A-3) -20, the polymer contains a divalent or higher valent alkylene group and R ⁴⁷ which is an arylene group, and the polymer within or between the molecules is crosslinked. May be.

In the above formulas (A-3) -19 and (A-3) -20, R ⁴³ is the same as described above, and R ⁴⁷ is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or phenylene. An arylene group such as a group, and may contain a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. e1 is an integer of 1 to 3.

  In particular, the repeating unit b in which the hydrogen atom of the carboxyl group is substituted with an acid labile group represented by the above formula (A-3) has an exo structure represented by the following formula (A-3) -21 (meta ) A repeating unit of an acrylic ester is preferred.

（式中、Ｒ^２、ｂは前述の通り、Ｒ^ｃ３は炭素数１〜８の直鎖状、分岐状、もしくは環状のアルキル基、又は炭素数６〜２０の置換されていてもよいアリール基を示す。Ｒ^ｃ４〜Ｒ^ｃ９及びＲ^ｃ１２、Ｒ^ｃ１３は、それぞれ独立に水素原子又は炭素数１〜１５のヘテロ原子を含んでもよい１価の炭化水素基を示し、Ｒ^ｃ１０、Ｒ^ｃ１１は水素原子を示す。あるいは、Ｒ^ｃ４とＲ^ｃ５、Ｒ^ｃ６とＲ^ｃ８、Ｒ^ｃ６とＲ^ｃ９、Ｒ^ｃ７とＲ^ｃ９、Ｒ^ｃ７とＲ^ｃ１３、Ｒ^ｃ８とＲ^ｃ１２、Ｒ^ｃ１０とＲ^ｃ１１又はＲ^ｃ１１とＲ^ｃ１２は互いに環を形成していてもよく、その場合には炭素数１〜１５のヘテロ原子を含んでもよい２価の炭化水素基を示す。またＲ^ｃ４とＲ^ｃ１３、Ｒ^ｃ１０とＲ^ｃ１３又はＲ^ｃ６とＲ^ｃ８は隣接する炭素に結合するもの同士で何も介さずに結合し、二重結合を形成してもよい。Ｒ^ｃ１４は水素原子、又は炭素数１〜１５の直鎖状、分岐状、もしくは環状のアルキル基を示す。また、本式により、鏡像体も表す。）

(Wherein R ² and b are as described above, R ^c3 is a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms, or an optionally substituted aryl group having 6 to 20 carbon atoms. R ^{c4 to} R ^c9 and R ^c12 and R ^c13 each independently represent a hydrogen atom or a monovalent hydrocarbon group that may contain a heteroatom having 1 to 15 carbon atoms, and R ^c10 and R ^c11 represent hydrogen. R ^c4 and R ^c5 , R ^c6 and R ^c8 , R ^c6 and R ^c9 , R ^c7 and R ^c9 , R ^c7 and R ^c13 , R ^c8 and R ^c12 , R ^c10 and R ^c11 or R ^c11 And R ^c12 may form a ring with each other, and in this case, a divalent hydrocarbon group which may contain a hetero atom having 1 to 15 carbon atoms, R ^c4 and R ^c13 , R ^c10 and R ^{c c13} or ^{R c6} and ^{R c8} is next to Nothing binds not through with each other those that bind to carbon double bonds may be formed .R ^c14 is a hydrogen atom, or of the straight, alkyl branched or cyclic (This group also represents a mirror image.)

  Here, an ester monomer for obtaining a repeating unit having an exo structure represented by the above formula (A-3) -21 is disclosed in JP 2000-327633 A. Specific examples include the following, but are not limited thereto.

  Furthermore, as the repeating unit b in which the hydrogen atom of the carboxyl group is substituted with an acid labile group represented by the above formula (A-3), frangyl, tetrahydrofurandiyl represented by the following formula (A-3) -22, or A repeating unit of (meth) acrylic acid ester having oxanorbornanediyl can be preferably exemplified.

（式中、Ｒ^２、ｂは前述の通りである。Ｒ^ｃ１４、Ｒ^ｃ１５は、それぞれ独立に炭素数１〜１０の直鎖状、分岐状又は環状の１価炭化水素基を示す。あるいは、Ｒ^ｃ１４、Ｒ^ｃ１５は互いに結合してこれらが結合する炭素原子と共に脂肪族炭化水素環を形成してもよい。Ｒ^ｃ１６はフランジイル、テトラヒドロフランジイル、及びオキサノルボルナンジイルから選ばれる２価の基を示す。Ｒ^ｃ１７は水素原子、又はヘテロ原子を含んでもよい炭素数１〜１０の直鎖状、分岐状、もしくは環状の１価炭化水素基を示す。）

(Wherein R ² and b are as defined above. R ^c14 and R ^c15 each independently represent a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^c14 and R ^c15 may be bonded to each other to form an aliphatic hydrocarbon ring together with the carbon atom to which they are bonded, and R ^c16 represents a divalent group selected from ^flangedyl , tetrahydrofurandiyl, and ^{oxanorbornanediyl.} R ^c17 represents a hydrogen atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom.)

  Monomers for obtaining repeat units substituted with acid labile groups having frangiyl, tetrahydrofurandiyl, or oxanorbornanediyl are exemplified below. Ac represents an acetyl group and Me represents a methyl group.

（式中、Ｒ^１０１、Ｒ^１０２、Ｒ^１０９は、それぞれ独立に水素原子、炭素数１〜４のアルキル基、アルコキシ基、アルカノイル基、アルコキシカルボニル基、ヒドロキシル基、炭素数６〜１０のアリール基、ハロゲン原子、又はシアノ基である。Ｒ^１０７は水素原子、炭素数１〜１２の直鎖状、分岐状、環状のアルキル基であり、酸素原子又は硫黄原子を有していてもよく、炭素数２〜１２のアルケニル基、炭素数２〜１２のアルキニル基、炭素数６〜１０のアリール基である。Ｒ^１０３、Ｒ^１０４、Ｒ^１０５、Ｒ^１０６は、それぞれ独立に水素原子、あるいはＲ^１０３とＲ^１０４、Ｒ^１０４とＲ^１０５、Ｒ^１０５とＲ^１０６が結合してベンゼン環を形成しても良い。Ｒ^１００、Ｒ^１０８はそれぞれ独立に水素原子又はメチル基を示す。Ｘ^１は、単結合、−Ｃ（＝Ｏ）−Ｏ−Ｒ’−、フェニレン基、又はナフチレン基である。Ｒ’は炭素数１〜１０の直鎖状、分岐状、又は環状のアルキレン基であり、エステル基、エーテル基、又はラクトン環を有していても良い。ｓ、ｔ、ｕは、それぞれ独立に１〜４の整数である。） Furthermore, as the repeating unit b in which the hydrogen atom of the carboxyl group is substituted with the acid labile group represented by the above formula (A-3), fluorene represented by the following formula (A-3) -23, the following formula (A- 3) The repeating unit of (meth) acrylic acid ester having acenaphthylene represented by -24 can be preferably exemplified.

(In the formula, R ¹⁰¹ , R ¹⁰² and R ¹⁰⁹ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, an alkanoyl group, an alkoxycarbonyl group, a hydroxyl group, or an aryl group having 6 to 10 carbon atoms. R ¹⁰⁷ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, which may have an oxygen atom or a sulfur atom, and is a carbon atom. An alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, and an aryl group having 6 to 10 carbon atoms, each of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , and R ¹⁰⁶ is independently a hydrogen atom or R ¹⁰³ and ^{R 104, R 104} and ^{R 105, R 105} and ^{R 106} is may form a benzene ring bonded ^{.R 100, R 108} hydrogen or menu are each independently .X ¹ showing the Le group is a single bond, -C (= O) -O- R'-, phenylene group, or a naphthylene group .R 'is a straight, branched, Or a cyclic alkylene group, which may have an ester group, an ether group, or a lactone ring, and s, t, and u are each independently an integer of 1 to 4.)

  Further, in the present invention, the base resin includes, in addition to the repeating unit a having the group represented by the general formula (1) and the repeating unit b in which the hydrogen atom of the carboxyl group is substituted with an acid labile group, , A repeating unit c having an adhesive group selected from a hydroxyl group, a lactone ring, an ether group, an ester group, a carbonyl group and a cyano group has a weight average molecular weight in the range of 1,000 to 500,000. It is preferably a polymer compound (where 0 <a <1.0, 0 <b <1.0, 0 <c ≦ 0.9, 0.2 ≦ a + b + c ≦ 1.0). .

  Specific examples of the monomer for obtaining the repeating unit c having any one of a hydroxyl group, a lactone ring, an ether group, an ester group, a carbonyl group, and a cyano group as an adhesive group can be given below.

  In the case of a monomer having a hydroxyl group, for example, the hydroxyl group may be substituted with an acetal that can be easily deprotected with an acid such as an ethoxyethoxy group at the time of polymerization, and the deprotection may be performed with a weak acid and water after the polymerization. Alternatively, it may be substituted with a formyl group, a pivaloyl group or the like, and subjected to alkali hydrolysis after polymerization.

  The polymer compound serving as the base resin of the positive resist material of the present invention contains a repeating unit d such as indene d1, acenaphthylene d2, chromone d3, coumarin d4, norbornadiene d5 represented by the following general formula (5). It can also be polymerized.

（式中、Ｒ^１１０〜Ｒ^１１４は、それぞれ独立に水素原子、炭素数１〜３０のアルキル基、一部もしくは全てがハロゲン原子で置換されたアルキル基、ヒドロキシル基、アルコキシ基、アルカノイル基、アルコキシカルボニル基、炭素数６〜１０のアリール基、ハロゲン原子、又は１，１，１，３，３，３−ヘキサフルオロ−２−プロパノール基である。Ｙはメチレン基、酸素原子、又は硫黄原子である。ｄ１は０≦ｄ１≦０．４、ｄ２は０≦ｄ２≦０．４、ｄ３は０≦ｄ３≦０．４、ｄ４は０≦ｄ４≦０．４、ｄ５は０≦ｄ５≦０．４、０≦ｄ１＋ｄ２＋ｄ３＋ｄ４＋ｄ５≦０．４である。）

Wherein R ^{110 to} R ¹¹⁴ are each independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkyl group partially or entirely substituted with a halogen atom, a hydroxyl group, an alkoxy group, an alkanoyl group, an alkoxy group A carbonyl group, an aryl group having 6 to 10 carbon atoms, a halogen atom, or a 1,1,1,3,3,3-hexafluoro-2-propanol group, where Y is a methylene group, an oxygen atom, or a sulfur atom; D1 is 0 ≦ d1 ≦ 0.4, d2 is 0 ≦ d2 ≦ 0.4, d3 is 0 ≦ d3 ≦ 0.4, d4 is 0 ≦ d4 ≦ 0.4, d5 is 0 ≦ d5 ≦ 0. 4, 0 ≦ d1 + d2 + d3 + d4 + d5 ≦ 0.4.)

（式中Ｒ^１１５、Ｒ^１１８は、それぞれ独立に水素原子又はメチル基を示し、Ｒ^１１７、Ｒ^１２０は酸不安定基である。Ｒ^１１６、Ｒ^１１９は、それぞれ独立に水素原子、炭素数１〜６の直鎖状、分岐状、もしくは環状のアルキル基、又は炭素数２〜６のアルケニル基であり、ｑ、ｒは１又は２である。ｅ１は０≦ｅ１≦０．４、ｅ２は０≦ｅ２≦０．４、０≦ｅ１＋ｅ２≦０．４である。）
尚、酸不安定基Ｒ^１１７、Ｒ^１２０としてはＡＬ−１、ＡＬ−２、ＡＬ−３に示されるものを用いることができる。 Furthermore, the polymer compound serving as the base resin of the positive resist material of the present invention includes repeating units e1 and e2 in which the hydrogen atom of the phenolic hydroxyl group represented by the following general formula (6) is substituted with an acid labile group. Additional copolymerization is also possible.

(Wherein R ¹¹⁵ and R ¹¹⁸ each independently represent a hydrogen atom or a methyl group, and R ¹¹⁷ and R ¹²⁰ are acid labile groups. R ¹¹⁶ and R ¹¹⁹ each independently represent a hydrogen atom and a carbon number of 1). A linear, branched, or cyclic alkyl group of ˜6, or an alkenyl group of 2-6 carbon atoms, q and r are 1 or 2. e1 is 0 ≦ e1 ≦ 0.4, and e2 is (0 ≦ e2 ≦ 0.4, 0 ≦ e1 + e2 ≦ 0.4)
As the acid labile group ^{R 117, R 120} may be the same as those shown in AL-1, AL-2, AL-3.

  Examples of the repeating unit f that can be copolymerized in addition to the repeating units a, b, c, d, and e include styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, and methylene indan.

In addition, an onium salt acid generator (repeating unit g) having a polymerizable olefin may be copolymerized.
For example, Japanese Patent Application Laid-Open No. 2006-045311 proposes a sulfonium salt and an iodonium salt having a polymerizable olefin that generates a specific sulfonic acid. Further, for example, JP 2006-178317 A proposes a sulfonium salt in which a sulfonic acid is directly bonded to the main chain.

（式中、Ｒ^２０、Ｒ^２４、Ｒ^２８は、それぞれ独立に水素原子又はメチル基、Ｒ^２１は単結合、フェニレン基、−Ｏ−Ｒ−、又は−Ｃ（＝Ｏ）−Ｙ−Ｒ−である。Ｙは酸素原子又はＮＨ、Ｒは炭素数１〜６の直鎖状、分岐状、もしくは環状のアルキレン基、フェニレン基、又はアルケニレン基であり、カルボニル基、エステル基、エーテル基、又はヒドロキシル基を含んでいてもよい。Ｒ^２２、Ｒ^２３、Ｒ^２５、Ｒ^２６、Ｒ^２７、Ｒ^２９、Ｒ^３０、Ｒ^３１は同一又は異種の、カルボニル基、エステル基又はエーテル基を含んでいてもよい炭素数１〜１２の直鎖状、分岐状、もしくは環状のアルキル基、炭素数６〜１２のアリール基、炭素数７〜２０のアラルキル基、又はチオフェニル基を表す。Ｚ_０は単結合、メチレン基、エチレン基、フェニレン基、フッ素化されたフェニレン基、−Ｏ−Ｒ^３２−、又は−Ｃ（＝Ｏ）−Ｚ_１−Ｒ^３２−である。Ｚ_１は酸素原子又はＮＨ、Ｒ^３２は炭素数１〜６の直鎖状、分岐状、もしくは環状のアルキレン基、フェニレン基又はアルケニレン基であり、カルボニル基、エステル基、エーテル基又はヒドロキシル基を含んでいてもよい。Ｍ⁻は非求核性対向イオンを表す。ｇ１は０≦ｇ１≦０．３、ｇ２は０≦ｇ２≦０．３、ｇ３は０≦ｇ３≦０．３、０≦ｇ１＋ｇ２＋ｇ３≦０．３である。） In the present invention, it is particularly preferable to copolymerize repeating units g1, g2, and g3 having a sulfonium salt represented by the following general formula (7).

(Wherein R ²⁰ , R ²⁴ , and R ²⁸ are each independently a hydrogen atom or a methyl group, R ²¹ is a single bond, a phenylene group, —O—R—, or —C (═O) —Y—R—. Y is an oxygen atom or NH, R is a linear, branched, or cyclic alkylene group, phenylene group, or alkenylene group having 1 to 6 carbon atoms, and is a carbonyl group, an ester group, an ether group, or R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁹ , R ³⁰ , R ³¹ may contain the same or different carbonyl group, ester group or ether group. A linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a thiophenyl group, and Z ₀ is a single bond. , Methylene group, A tylene group, a phenylene group, a fluorinated phenylene group, —O—R ³² —, or —C (═O) —Z ₁ —R ³² —, wherein Z ₁ is an oxygen atom or NH, and R ³² is the number of carbon atoms. 1 to 6 linear, branched, or cyclic alkylene group, phenylene group, or alkenylene group, which may contain a carbonyl group, an ester group, an ether group, or a hydroxyl group, and M ⁻ is non-nucleophilic. (G1 is 0 ≦ g1 ≦ 0.3, g2 is 0 ≦ g2 ≦ 0.3, g3 is 0 ≦ g3 ≦ 0.3, and 0 ≦ g1 + g2 + g3 ≦ 0.3.)

Examples of non-nucleophilic counter ions of M ⁻ include halide ions such as chloride ions and bromide ions, triflate, fluoroalkyl sulfonates such as 1,1,1-trifluoroethanesulfonate, nonafluorobutanesulfonate, tosylate, and benzene. Sulfonate, 4-fluorobenzene sulfonate, aryl sulfonate such as 1,2,3,4,5-pentafluorobenzene sulfonate, alkyl sulfonate such as mesylate and butane sulfonate, bis (trifluoromethylsulfonyl) imide, bis (perfluoroethyl) Examples include imide acids such as sulfonyl) imide and bis (perfluorobutylsulfonyl) imide, and methido acids such as tris (trifluoromethylsulfonyl) methide and tris (perfluoroethylsulfonyl) methide. Can do.

  In this manner, by repeating the copolymerization of the repeating unit g and bonding the acid generator to the polymer main chain, the acid diffusion can be reduced and the resolution can be prevented from being lowered due to the acid diffusion blur. In addition, since the acid generator is uniformly dispersed, roughness (LWR) is improved.

  In order to synthesize these high-molecular compounds that serve as the base resin of the positive resist material of the present invention, one method is to start radical polymerization in an organic solvent with a desired monomer among the monomers that give the repeating units a to g. A polymer compound of a copolymer can be obtained by adding an agent and performing heat polymerization.

  Examples of the organic solvent used at the time of polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, dioxane and the like. As polymerization initiators, 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobis (2-methylpropionate) ), Benzoyl peroxide, lauroyl peroxide and the like, and preferably polymerized by heating to 50 to 80 ° C. The reaction time is 2 to 100 hours, preferably 5 to 20 hours.

  When copolymerizing hydroxystyrene and hydroxyvinylnaphthalene, acetoxystyrene and acetoxyvinylnaphthalene are used in place of hydroxystyrene and hydroxyvinylnaphthalene, and after polymerization, the acetoxy group is deprotected by the above alkaline hydrolysis to produce polyhydroxystyrene and hydroxyhydroxyl. There is also a method of making polyvinyl naphthalene.

  Ammonia water, triethylamine, etc. can be used as the base during the alkali hydrolysis. The reaction temperature is −20 to 100 ° C., preferably 0 to 60 ° C., and the reaction time is 0.2 to 100 hours, preferably 0.5 to 20 hours.

  Here, the ratio of the repeating units a to c is 0 <a <1.0, 0 <b <1.0, 0 ≦ c ≦ 0.9, particularly 0 <c ≦ 0.9, 0.2 ≦ a + b + c. ≦ 1.0, preferably 0.02 ≦ a ≦ 0.9, 0.1 ≦ b ≦ 0.8, 0.1 ≦ c ≦ 0.8, 0.3 ≦ a + b + c ≦ 1.0, and more Preferably, 0.05 ≦ a ≦ 0.8, 0.15 ≦ b ≦ 0.7, 0.15 ≦ c ≦ 0.7, and 0.4 ≦ a + b + c ≦ 1.0.

  Further, when repeating units d to g are included, the ratio of the repeating units d to g is preferably 0 ≦ d + e + f + g ≦ 0.8, particularly preferably 0 ≦ d + e + f + g ≦ 0.7, and a + b + c + d + e + f + g = 1.

  For example, a + b + c = 1 means that in a polymer compound containing repeating units a, b and c, the total amount of repeating units a, b and c is 100 mol% with respect to the total amount of all repeating units. A + b + c <1 means that the total amount of the repeating units a, b and c is less than 100 mol% with respect to the total amount of all the repeating units and has other repeating units in addition to a, b and c. It shows that.

The polymer compound used in the positive resist material of the present invention has a weight average molecular weight of 1,000 to 500,000, preferably 2,000 to 30,000. If the weight average molecular weight is too small, the resist material is inferior in heat resistance. If the weight average molecular weight is too large, the alkali solubility is lowered, and a trailing phenomenon is likely to occur after pattern formation.
The weight average molecular weight (Mw) is a measured value in terms of polystyrene using gel permeation chromatography (GPC).

  Furthermore, in the high molecular compound used in the positive resist material of the present invention, when the molecular weight distribution (Mw / Mn) of the multi-component copolymer is wide, there is a low molecular weight or high molecular weight polymer. There is a possibility that foreign matter is seen on the pattern or the shape of the pattern is deteriorated. Therefore, since the influence of such molecular weight and molecular weight distribution tends to increase as the pattern rule becomes finer, in order to obtain a resist material suitably used for fine pattern dimensions, the multi-component copolymer to be used is obtained. The molecular weight distribution is preferably from 1.0 to 2.0, particularly preferably from 1.0 to 1.5 and narrow dispersion.

  It is also possible to blend two or more polymers having different composition ratios, molecular weight distributions and molecular weights, or polymers not copolymerized with fluorescein methacrylate.

  The polymer compound used in the present invention is suitable as a base resin for a positive resist material. Such a polymer compound is used as a base resin, and an organic solvent, an acid generator, a dissolution controller, a basic compound, an interface By combining the activator and the like appropriately in accordance with the purpose to form a positive resist material, the dissolution rate of the polymer compound in the developing solution is accelerated by a catalytic reaction in the exposed area, so that a highly sensitive positive resist is formed. Type resist material, resist film dissolution contrast and acid diffusion rate suppression effect is high, so resolution is high, exposure margin is excellent, process adaptability is good, and pattern shape after exposure is good However, it shows better roughness (LWR), especially because it can suppress acid diffusion, so the density difference between the density and the density is small. It can be very effective as a resist material for SI.

In particular, when a chemically amplified positive resist material containing an acid generator and utilizing an acid catalyzed reaction is used, the sensitivity can be increased, and various characteristics are further improved and extremely useful. .
For example, a compound that generates an acid in response to actinic rays or radiation (photoacid generator) may be contained as the acid generator. The component of the photoacid generator may be any compound that generates an acid upon irradiation with high energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, and the like.

  Specific examples of the acid generator are described in paragraphs [0139] to [0160] of JP-A-2008-239918, and these can be used alone or in combination of two or more.

Further, by adding a dissolution control agent to the positive resist material of the present invention, the difference in dissolution rate between the exposed area and the unexposed area can be further increased, and the resolution can be further improved.
Furthermore, by adding a basic compound, for example, the acid diffusion rate in the resist film can be suppressed to further improve the resolution, and by adding a surfactant, the coatability of the resist material can be further improved. Alternatively, it can be controlled.

  Specific examples of the organic solvent that can be contained in the positive resist material of the present invention include paragraphs [0162] to [0163] of JP-A-2008-239918, and specific examples of the basic compound include paragraph [0164]. To [0181], specific examples of surfactants are described in paragraphs [0182] to [0183], and specific examples of dissolution control agents are described in paragraphs [0185] to [0192].

  Furthermore, a polymer-type quencher described in JP-A-2008-239918 can also be added. Further, if necessary, carboxylic acid compounds and acetylene alcohols can be added. Specific examples of the carboxylic acid compounds include those described in paragraphs [0193] to [0201] of JP-A-2008-239918, acetylene alcohols. Specific examples are described in paragraphs [0202] to [0204].

  These enhance the rectangularity of the resist after patterning by being oriented on the resist surface after coating. The polymer quencher also has an effect of preventing pattern film loss and pattern top rounding when a protective film for immersion exposure is applied.

  In the positive resist composition of the present invention, the amount of the acid generator is preferably 0.01 to 100 parts by weight, more preferably 0.1 to 80 parts by weight, based on 100 parts by weight of the base resin. Is preferably 50 to 10,000 parts by mass, and particularly preferably 100 to 5,000 parts by mass with respect to 100 parts by mass of the base resin. Moreover, 0-100 mass parts, especially 0-40 mass parts, a basic compound are 0-100 mass parts with respect to 100 mass parts of base resins, especially 0.001-50 mass parts, surfactant is a surfactant. The blending amount is preferably 0 to 10 parts by mass, particularly 0.0001 to 5 parts by mass.

  The positive resist material of the present invention thus prepared is developed using at least a step of applying the positive resist material on a substrate, a step of exposing to high energy rays after heat treatment, and a developer. By performing the process, it can be used as a method for forming a pattern on a semiconductor substrate, a mask substrate, or the like.

  In this case, various positive resist materials of the present invention, for example, a chemically amplified positive resist material containing a polymer compound containing a repeating unit represented by the general formula (4), an organic solvent, an acid generator, and a basic compound are used. In the case of use in the manufacture of integrated circuits, a known lithography technique can be applied, although not particularly limited.

For example, the positive resist material of the present invention is applied to a substrate for manufacturing an integrated circuit (Si, SiO ₂ , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for manufacturing a mask circuit (Cr , CrO, CrON, MoSi, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so that the coating film thickness is 0.1 to 2.0 μm. To do. This is pre-baked on a hot plate at 60 to 150 ° C. for 10 seconds to 30 minutes, preferably 80 to 120 ° C. for 30 seconds to 20 minutes.

Next, the target pattern is passed through a predetermined mask with a light source selected from high energy rays such as ultraviolet rays, far ultraviolet rays, electron beams, X-rays, excimer lasers, γ rays, synchrotron radiation, and vacuum ultraviolet rays (soft X-rays). Alternatively, direct exposure is performed. It is preferable to expose so that the exposure amount is about 1 to 200 mJ / cm ² , preferably 10 to 100 mJ / cm ² , or 0.1 to 100 μC, preferably about 0.5 to 50 μC. Next, post-exposure baking (PEB) is performed on a hot plate at 60 to 150 ° C. for 10 seconds to 30 minutes, preferably 80 to 120 ° C. for 30 seconds to 20 minutes.

  Further, 0.1 to 5% by mass, preferably 2 to 10% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide ( Using an aqueous developer such as TBAH), development is performed for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as a dip method, a paddle method, or a spray method. As a result, the irradiated portion is dissolved in the developer, and the unexposed portion is not dissolved, and a desired positive pattern is formed on the substrate.

  The resist material of the present invention is an electron beam, a vacuum ultraviolet ray (soft X-ray), an X-ray, a γ-ray, a synchrotron radiation, particularly an electron beam or a soft X-ray having a wavelength in the range of 3 to 15 nm among high energy rays. Ideal for fine patterning.

  Further, as a developer used in the development process, TEAH, TPAH, and TBAH having a longer alkyl chain have an effect of preventing pattern collapse by reducing swelling during development, as compared to a widely used TMAH aqueous solution. This is preferable. For example, in Japanese Patent Publication No. 3429592, a repeating unit having an alicyclic structure such as adamantane methacrylate is copolymerized with a repeating unit having an acid labile group such as t-butyl methacrylate, so that there is no hydrophilic group and repellent properties. An example using an aqueous TBAH solution for the development of highly aqueous polymers is presented.

  As the tetramethylammonium hydroxide (TMAH) developer, a 2.38% by weight aqueous solution is most widely used. This corresponds to 0.26N, and it is preferable that the TEAH, TPAH, and TBAH aqueous solutions have the same normality. The weights of TEAH, TPAH, and TBAH that are 0.26N are 3.84, 5.31, and 6.78% by weight, respectively.

  In a pattern of 32 nm or less that is resolved by EB or EUV, a phenomenon occurs in which lines are twisted, the lines are stuck together, or the stuck lines are tilted. This is thought to be because the lines swollen and swollen in the developer are stuck together. Since the swollen line is soft like a sponge containing a developer, it tends to collapse due to the stress of rinsing. For this reason, the developer having a long alkyl chain has the effect of preventing swelling and preventing pattern collapse.

  Since the resist material of the present invention contains a polymer compound containing fluorescein as a repeating unit as a base resin, when the resist pattern after development is irradiated with light, it emits green phosphorescence having a wavelength of 521 nm. The irradiation light is preferably an Ar laser having a wavelength of 488 nm, and the position can be observed by observing the emitted resist pattern with a CCD camera with a microscope.

EXAMPLES Hereinafter, although a synthesis example, a comparative synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
The weight average molecular weight (Mw) is a measured value in terms of polystyrene using gel permeation chromatography (GPC).
Moreover, the adhesion monomers 1 and 2 and the PAG monomer 1 used in the following synthesis examples are as follows.

Adhesive monomer 1: Methacrylic acid (2-oxo-1,3-benzooxathiol-5-i
Le)
Adhesive monomer 2: methacrylic acid (2-oxo-2,3-dihydrobenzoxazole-
5-yl)
PAG monomer 1: triphenylsulfonium 1,1,3,3,3-pentafluoro-
2-Methacryloyloxypropane-1-sulfonate

[Synthesis Example 1]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 8.2 g, methacrylic acid fluorescein 8.0 g, methacrylate 5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl 11. 1 g and 40 g of tetrahydrofuran as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid fluorescein ester: methacrylate 5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl = 0.30: 0.20: 0 .50
Weight average molecular weight (Mw) = 9,700
Molecular weight distribution (Mw / Mn) = 1.83
This polymer compound is referred to as (Polymer 1).

[Synthesis Example 2]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 8.2 g, methacrylic acid fluorescein ester 8.0 g, adhesion monomer 1 9.4 g, PAG monomer 1 5.6 g, and tetrahydrofuran 40 g as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid fluorescein ester: adhesive monomer 1: PAG monomer 1 = 0.30: 0.20: 0.40: 0.10
Weight average molecular weight (Mw) = 9,200
Molecular weight distribution (Mw / Mn) = 1.68
This polymer compound is referred to as (Polymer 2).

[Synthesis Example 3]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 8.2 g, methacrylic acid fluorescein ester 8.0 g, adhesive monomer 2 8.7 g, PAG monomer 1 5.6 g, and tetrahydrofuran 40 g as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid fluorescein ester: adhesive monomer 2: PAG monomer 1 = 0.30: 0.20: 0.40: 0.10
Weight average molecular weight (Mw) = 7,300
Molecular weight distribution (Mw / Mn) = 1.88
This polymer compound is referred to as (Polymer 3).

[Synthesis Example 4]
Acetic acid acenaphthenyl 8.3 g, methacrylic acid fluorescein ester 12.0 g, methacrylic acid 3-oxo-2,7-dioxatricyclo [4.2.1.0 ^4,8 ] nonan-9-yl in a 2 L flask 6.7 g, 5.6 g of PAG monomer 3 and 40 g of tetrahydrofuran as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid Acenaphthenyl: Methacrylic acid fluorescein ester: Methacrylic acid 3-oxo-2,7-dioxatricyclo [4.2.1.0 ^4,8 ] nonan-9-yl: PAG monomer 1 = 0.30: 0 .30: 0.30: 0.10
Weight average molecular weight (Mw) = 9,300
Molecular weight distribution (Mw / Mn) = 1.68
This polymer compound is referred to as (Polymer 4).

[Synthesis Example 5]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 5.5 g, methacrylic acid-4-tert-butoxyphenyl 3.5 g, methacrylic acid fluorescein ester 22.0 g, PAG monomer 1 5.6 g, and tetrahydrofuran 40 g as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid-4-tert-butoxyphenyl: methacrylic acid fluorescein ester: PAG monomer 1 = 0.20: 0.15: 0.55: 0.10
Weight average molecular weight (Mw) = 9,300
Molecular weight distribution (Mw / Mn) = 1.67
This polymer compound is referred to as (Polymer 5).

[Synthesis Example 6]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 8.2 g, methacrylic acid fluorescein ester 16.0 g, methacrylic acid 3-oxo-2,7-dioxatricyclo [4.2.1.0 ^4,8 ] nonan-9-yl 4 0.5 g, 5.6 g of PAG monomer 1 and 40 g of tetrahydrofuran as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid fluorescein ester: methacrylic acid 3-oxo-2,7-dioxatricyclo [4.2.1.0 ^4,8 ] nonan-9-yl: PAG monomer 1 = 0. 30: 0.40: 0.20: 0.10
Weight average molecular weight (Mw) = 9,100
Molecular weight distribution (Mw / Mn) = 1.88
This polymer compound is referred to as (Polymer 6).

[Synthesis Example 7]
In a 2 L flask, methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl 8.2 g, methacrylic acid fluorescein ester 16.0 g, methacrylic acid 4-hexafluoroisopropanol cyclohexyl 4.5 g, PAG monomer 1 5.6 g, and tetrahydrofuran 40 g as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60 ° C. and reacted for 15 hours. This reaction solution was precipitated in 1 L of isopropyl alcohol, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain a white polymer.
When the obtained polymer was measured by ¹³ C, ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: methacrylic acid fluorescein ester: methacrylic acid 4-hexafluoroisopropanol cyclohexyl: PAG monomer 1 = 0.30: 0.40: 0.20: 0.10
Weight average molecular weight (Mw) = 7,100
Molecular weight distribution (Mw / Mn) = 1.83
This polymer compound is referred to as (Polymer 7).

[Comparative Synthesis Example 1]
The following polymers were synthesized by the same method as in the above synthesis example.
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: 5-oxo-4-oxatricyclomethacrylate [4.2.1.0 ^3,7 ] nonan-2-yl: 4-hydroxyphenyl methacrylate = 0.30: 0.40 : 0.30
Weight average molecular weight (Mw) = 8,200
Molecular weight distribution (Mw / Mn) = 1.89
This polymer compound is referred to as (Comparative Polymer 1).

[Comparative Synthesis Example 2]
Copolymer composition ratio (molar ratio)
Methacrylic acid-3-ethyl-3-exotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecanyl: 4-hydroxyphenyl methacrylate: 3-oxo-2,7-dioxatricyclo [4.2.1.0 ^4,8 ] nonan-9-yl methacrylate: PAG monomer 1 = 0.30: 0.20: 0.40: 0.10
Weight average molecular weight (Mw) = 7,300
Molecular weight distribution (Mw / Mn) = 1.88
This polymer compound is referred to as (Comparative Polymer 2).

[Examples 1-7, Comparative Examples 1-2]
Electron Beam Drawing Evaluation In the electron beam drawing evaluation, the polymer compound synthesized above is used, as shown in Table 1, in a solvent in which 100 ppm of the surfactant FC-4430 manufactured by Sumitomo 3M Limited is dissolved as a surfactant. A positive resist material was prepared by filtering the solution dissolved with the composition described above through a 0.2 μm size filter.

In addition, each composition in Table 1 and Table 2 mentioned later is as follows.
Polymers 1 to 7: Comparative polymer compounds obtained in Synthesis Examples 1 to 7, Polymers 1 and 2: Polymer compounds obtained in Comparative Synthesis Examples 1 and 2 Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)
PGME (propylene glycol monomethyl ether)
CyH (cyclohexanone)
Acid generator: PAG1 (see structural formula below)
Basic compounds: Amine 1 and Amine 2 (see the structural formula below)

  The obtained positive resist material was spin-coated on a 6-inch (150 mm) hexamethyldisilazane (HMDS) vapor primed Si substrate using a clean track Mark 5 (manufactured by Tokyo Electron Ltd.), A 100 nm resist film was prepared by pre-baking on a hot plate at 110 ° C. for 60 seconds. To this, drawing in a vacuum chamber was performed at an HV voltage of 50 keV using HL-800D manufactured by Hitachi, Ltd.

Immediately after drawing, a post-exposure bake (PEB) was performed on a hot plate at 95 ° C. for 60 seconds using a clean truck Mark 5 (manufactured by Tokyo Electron Ltd.) and paddled with a 2.38 mass% TMAH aqueous solution for 30 seconds. Development was performed to obtain a positive pattern.
The obtained resist pattern was evaluated as follows.
The exposure amount for resolving 100 nm line and space at 1: 1 was defined as the sensitivity of the resist, and the minimum dimension at the exposure amount at this time was defined as the resolving power. The roughness (LWR) of 100 nm LS was measured by SEM.
Table 1 shows the resist composition and the results of sensitivity, resolution, and roughness (LWR) in EB exposure.

[Example 8, Comparative Example 3]
EUV Exposure Evaluation In the EUV exposure evaluation, a positive resist material was prepared by filtering a solution dissolved in the composition shown in Table 2 using a polymer compound synthesized above with a 0.2 μm size filter.
The obtained positive resist material was spin-coated on a 4-inch (100 mm) diameter Si substrate treated with hexamethyldisilazane (HMDS) vapor prime and pre-baked on a hot plate at 105 ° C. for 60 seconds to give a 50 nm resist film Was made. This was subjected to EUV exposure with NA 0.3 and dipole illumination.

Immediately after exposure, post-exposure baking (PEB) was performed on a hot plate for 60 seconds, and paddle development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to obtain a positive pattern.
The obtained resist pattern was evaluated as follows.
The exposure amount for resolving 35 nm line and space at 1: 1 was defined as the sensitivity of the resist, and the minimum dimension of the exposure amount at this time was defined as the resolving power. The roughness (LWR) of 35 nm LS was measured by SEM.
Table 2 shows the resist composition and the results of sensitivity, resolution, and roughness (LWR) in EUV exposure.

From Tables 1 and 2, the positive resist materials (Examples 1 to 8) of the present invention satisfy sufficient resolution, sensitivity, and roughness (LWR) as compared with conventional positive resist materials (Comparative Examples 1 to 3). Furthermore, it was found that the resolution and roughness (LWR) characteristics can be further improved by copolymerizing an acid generator.
Further, in Examples 1 to 8 using the positive resist material of the present invention, the pattern shape after exposure was all good as a rectangle.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Claims (8)

A weight average molecular weight of 1,000 to 500, comprising at least a repeating unit a having a group represented by the following general formula (1) and a repeating unit b in which a hydrogen atom of a carboxyl group is substituted with an acid labile group A positive resist material containing 1,000,000 polymer compounds as a base resin.

The positive resist material according to claim 1, wherein the repeating unit a is represented by the following general formula (2).

(In the formula, R ¹ is a hydrogen atom or a methyl group. A is in the range of 0 <a <1.0.) The positive resist material according to claim 1, wherein the repeating unit b is represented by the following general formula (3).

(Wherein R ² represents a hydrogen atom or a methyl group, and R ³ represents an acid labile group. X represents a single bond, an ester group, a linking group having 1 to 12 carbon atoms having a lactone ring, a phenylene group, or a naphthylene group. B is in the range of 0 <b <1.0.)   A polymer obtained by copolymerizing a repeating unit c having an adhesive group selected from a hydroxyl group, a lactone ring, an ether group, an ester group, a carbonyl group, and a cyano group in addition to the repeating unit a and the repeating unit b. Containing a compound (where 0 <a <1.0, 0 <b <1.0, 0 <c ≦ 0.9, 0.2 ≦ a + b + c ≦ 1.0) as a base resin. The positive resist material according to any one of claims 1 to 3, characterized in that:   The positive resist material according to any one of claims 1 to 4, wherein the positive resist material is a chemically amplified positive resist material.   6. The positive resist material contains at least one of an organic solvent, an acid generator, a dissolution controller, a basic compound, and a surfactant. The positive resist material according to any one of the above.   At least a step of applying the positive resist material according to any one of claims 1 to 6 on a substrate, a step of exposing to high energy rays after heat treatment, and developing using a developer. A pattern forming method comprising the steps of:   The pattern forming method according to claim 7, wherein an electron beam or soft X-ray having a wavelength in the range of 3 to 15 nm is used as a light source in the step of exposing with the high energy beam.