JP2008145674A - Surface modifier for resist and method for formation of resist pattern with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface modifier for a resist modifying the surface of a photoresist film to sufficiently enhance the wettability with a developer solution and excellent in safety, and to provide a method for formation of a resist pattern with the modifier. <P>SOLUTION: The surface modifier for a resist consists of an aqueous solution containing: at least one kind of amine oxide compound having a 8-20C alkyl group or hydroxyalkyl group which may be interrupted by an oxygen atom and two of 1-5C alkyl groups or hydroxyalkyl groups; and at least one kind of amine oxide compound having two of 8-20C alkyl groups or hydroxyalkyl groups which may be interrupted by an oxygen atom and a 1-5C alkyl group or hydroxyalkyl group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resist surface modifier capable of modifying a photoresist film surface and improving wettability to a developer, and a resist pattern forming method using the same.

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology. As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line (436 nm) and i-line (365 nm) have been used, but now KrF excimer laser (248 nm) and ArF excimer laser (193 nm) are used. The production of semiconductor devices has been started, and an F ₂ excimer laser (157 nm) having a shorter wavelength than these excimer lasers is also being studied.

  Currently, a resin having a fluorine atom or a siloxane bond in a resin skeleton is used as a base resin of a photoresist composition used at a short wavelength of 200 nm or less because of its excellent transparency. However, since fluorine and siloxane are materials having high water repellency, the developer does not spread uniformly, and there is a risk of developing failure.

Therefore, recently, the photoresist film surface is treated with an aqueous solution containing a fluorosurfactant having an amine salt of carboxylic acid or sulfonic acid as a hydrophilic group to improve the wettability of the developer, followed by development. Has been proposed (see Patent Document 1).
JP 2006-259760 A

  However, the fluorine-based surfactants described in Patent Document 1 cannot sufficiently increase the wettability of the photoresist film surface to a desired level, and many have high toxicity and persistence. Therefore, there has been a demand for a resist surface modifier that can sufficiently improve the wettability with respect to the developer by modifying the photoresist film surface and is excellent in safety.

  The present invention has been made in view of such a conventional situation, and can improve the wettability with respect to a developer by modifying the photoresist film surface, and is excellent in safety. It is an object of the present invention to provide a modifier and a resist pattern forming method using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using an aqueous solution containing a mixture of specific amine oxide compounds, and the present invention has been completed. It was.

（式（１）、（２）中、Ｒ^１は酸素原子で中断されていてもよい炭素数８〜２０のアルキル基又はヒドロキシアルキル基を示し、ｎ及びｍは１〜５の整数を示す。）

（式（３）、（４）中、Ｒ^２及びＲ^３はそれぞれ独立に酸素原子で中断されていてもよい炭素数８〜２０のアルキル基又はヒドロキシアルキル基を示し、ｎは１〜５の整数を示す） That is, in the first aspect of the present invention, at least one amine oxide compound represented by the following general formulas (1) and (2) and an amine oxide compound represented by the following general formulas (3) and (4) are used. A resist surface modifier comprising an aqueous solution containing at least one of the above.

(Equation (1), (2), R ¹ represents an alkyl or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, n and m represents an integer of 1 to 5. )

(In the formulas (3) and (4), R ² and R ³ each independently represent an alkyl group or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, and n represents 1 to 5 Indicates an integer)

  The second aspect of the present invention includes a step of providing a photoresist film on a substrate, a step of selectively exposing the photoresist film through a mask pattern, and a step of exposing the photoresist film to the resist surface of the present invention. A method of forming a resist pattern comprising: a step of treating with a modifier; and a step of developing the photoresist film after the treatment with the resist surface modifier.

  According to the present invention, the photoresist film surface can be modified to be hydrophilic. Therefore, by treating the photoresist film with a resist surface modifier before development, the wettability with respect to the developer can be sufficiently increased, and the development failure can be prevented.

[Resist surface modifier]
The resist surface modifier of the present invention comprises an aqueous solution containing a mixture of specific amine oxide compounds. Hereinafter, each component constituting the resist surface modifier will be described in detail.

（式（１）、（２）中、Ｒ^１は酸素原子で中断されていてもよい炭素数８〜２０のアルキル基又はヒドロキシアルキル基を示し、ｎ及びｍは１〜５の整数を示す。）

（式（３）、（４）中、Ｒ^２及びＲ^３はそれぞれ独立に酸素原子で中断されていてもよい炭素数８〜２０のアルキル基又はヒドロキシアルキル基を示し、ｎは１〜５の整数を示す） <Amine oxide compound>
The amine oxide compound contained in the resist surface modifier is represented by at least one amine oxide compound represented by the following general formulas (1) and (2) and the following general formulas (3) and (4). A mixture with at least one amine oxide compound is used.

(Equation (1), (2), R ¹ represents an alkyl or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, n and m represents an integer of 1 to 5. )

(In the formulas (3) and (4), R ² and R ³ each independently represent an alkyl group or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, and n represents 1 to 5 Indicates an integer)

（式（５）、（６）中、Ｒ^４はアルキル基を示し、ｐ及びｑは式中の炭素数の合計が８〜２０となるような整数を示す。） R ¹ , R ² and R ³ in the formulas (1) to (4) are linear or branched long-chain alkyl groups having 8 to 20 carbon atoms, such as an octyl group, a nonyl group, a decyl group, Examples thereof include a lauryl group, a pentadecyl group, a myristyl group, a palmityl group, and a stearyl group. In this long chain alkyl group, the carbon chain may be interrupted by an oxygen atom. Examples of such a group include alkyloxyalkylene compounds represented by the following general formulas (5) and (6) or alkyl ( Polyoxyalkylene) compounds.

(In formulas (5) and (6), R ⁴ represents an alkyl group, and p and q represent integers such that the total number of carbon atoms in the formula is 8 to 20.)

  The two lower alkyl groups in the formula (1) are more preferably a lower alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group, and the two lower hydroxyalkyl groups in the formula (2) The group is more preferably a lower hydroxyalkyl group having 1 to 4 carbon atoms such as a methylol group, a hydroxyethyl group, a hydroxypropyl group, or a hydroxybutyl group. These may be either linear or branched.

  The two lower alkyl groups in formula (1) and the two lower hydroxyalkyl groups in formula (2) are preferably the same as each other, but may be different. Accordingly, preferred examples of the amine oxide compound represented by the formula (1) include octyldimethylamine oxide, dodecyldimethylamine oxide, decyldimethylamine oxide, lauryldimethylamine oxide, cetyldimethylamine oxide, stearyldimethylamine oxide, Long chain alkyldi-lower alkylamine oxides such as hexyl diethylamine oxide, nonyl diethylamine oxide, lauryl diethylamine oxide, isopentadecylmethylethylamine oxide, stearylmethylpropylamine oxide and the like, and preferred amine oxide compounds represented by formula (2) Examples include lauryl di (hydroxyethyl) amine oxide, cetyl diethanolamine oxide, stearyl di (hydroxyethyl). E) long chain alkyldi lower alkanolamine oxide such as amine oxide, long chain alkyloxyalkyldi lower alkylamine oxide such as dodecyloxyethoxyethoxyethyl di (methyl) amine oxide, stearyloxyethyl di (methyl) amine oxide It is done.

  Moreover, as one lower alkyl group in Formula (3), C1-C3 lower alkyl groups, such as a methyl group, an ethyl group, and a propyl group, are more preferable, and one lower alkyl group in Formula (4) The hydroxyalkyl group is more preferably a lower hydroxyalkyl group having 1 to 4 carbon atoms such as a methylol group, a hydroxyethyl group, a hydroxypropyl group, or a hydroxybutyl group. These may be either linear or branched.

R ² and R ^{3 in} formulas (3) and (4) are preferably the same as each other, but may be different from each other. Accordingly, preferred examples of the amine oxide compound represented by the formula (3) include dioctylmethylamine oxide, didodecylmethylamine oxide, didecylmethylamine oxide, dilaurylmethylamine oxide, dicetylmethylamine oxide, distearyl. Examples include di-long-chain alkyl lower alkyl amine oxides such as methylamine oxide, diisohexylethylamine oxide, dinonylethylamine oxide, dilaurylethylamine oxide, diisopentadecylethylamine oxide, distearylpropylamine oxide, and the formula (4) Preferred examples of the amine oxide compound represented by the formula are dilauryl (hydroxyethyl) amine oxide, dicetylethanolamine oxide, distearyl (hydroxyethyl) amine. Di-long-chain alkyl-lower alkanol amine oxide and di-dodecyloxy ethoxyethoxyethyl like N'okishido (methyl) amine oxide, di-long-chain alkyloxy (lower alkyl) amine oxides, such as distearyl oxyethyl (methyl) amine oxide.

  Here, the amine oxide compounds represented by the formulas (3) and (4) are insoluble in an aqueous solvent alone, but are mixed with the amine oxide compounds represented by the formulas (1) and (2). It can be dissolved in an aqueous solvent. Further, by mixing the amine oxide compounds represented by the formulas (1) and (2) with the amine oxide compounds represented by the formulas (3) and (4), the formulas (1) and (2) are used. The surface modification effect of the photoresist film can be improved as compared with the case where only the amine oxide compound is used.

  The mixing ratio of the amine oxide compounds represented by the formulas (1) and (2) and the amine oxide compounds represented by the formulas (3) and (4) is preferably 99: 1 to 80:20 by mass ratio, 95: 5-85: 15 is more preferable. When the ratio of the amine oxide compounds represented by the formulas (1) and (2) is larger than this range, the surface modification effect tends to be reduced, and when it is smaller than this range, the amine oxide compound may not be dissolved in the aqueous solvent.

  The total content of these amine oxide compounds is preferably 0.1 mass ppm to 10 mass% in the resist surface modifier. If the amount is less than 0.1 ppm by mass, the surface modification effect of the photoresist film is reduced, and it is difficult to disperse and diffuse on the photoresist film surface. If the amount exceeds 10% by mass, the resist surface modifier penetrates into the photoresist film and the photoresist film. May dissolve and the pattern shape may deteriorate.

<Solvent>
As the solvent for the resist surface modifier, water alone is preferably used, but a mixed solvent of water and a water-miscible organic solvent can be used as desired. Examples of the water-miscible organic solvent include monohydric alcohol-based organic solvents such as methanol, ethanol, and propanol, and polyhydric alcohol-based organic solvents such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, alkyl etherified products, and esterified products thereof. Is preferred.

  0.01-10 mass% is preferable in a solvent, and, as for the compounding quantity of this water-miscible organic solvent, 0.1-5 mass% is more preferable. Thus, by mix | blending a water miscible organic solvent, a resist surface modifier can be efficiently disperse | distributed and diffused on the photoresist film surface.

<Other ingredients>
If desired, the resist surface modifier may further contain a polyalkylene glycol (eg, polyethylene glycol, polypropylene glycol, poly (ethylene glycol-propylene glycol)) or an alkyl ether thereof (eg, methyl ether, ethyl ether). it can. 1 mass ppm-5 mass% are preferable in a resist surface modifier, and, as for these content, 0.1-3 mass% is more preferable. By containing this polyalkylene glycol or its alkyl ether, the resist surface modifier can be efficiently dispersed and diffused on the photoresist film surface.

  The resist surface modifier may further contain a soluble polymer containing a nitrogen atom in its molecular structure, that is, a polymer soluble in the solvent used, if desired. This nitrogen atom may be contained in the basic molecular chain of the polymer, or may be contained in the side chain as a nitrogen-containing substituent.

  Examples of the soluble polymer in which the nitrogen atom is contained in the backbone molecular chain include a polymer of a lower alkylene imine or a copolymer of another monomer that forms a water-soluble polymer alone with a lower alkylene imine. Among them, polyethyleneimine is particularly preferable because it is easily available. This polyethyleneimine can be easily produced by, for example, ring-closing polymerization of ethyleneimine in the presence of an acid catalyst such as carbon dioxide, chlorine, hydrobromic acid, p-toluenesulfonic acid, etc. can do.

  Moreover, as a soluble polymer which contains a nitrogen-containing substituent in a side chain, the polymer or copolymer of the unsaturated hydrocarbon which has an amino group or a substituted amino group, and a nitrogen-containing heterocyclic group is mentioned. Examples of the unsaturated hydrocarbon polymer having an amino group include polyallylamine. This polyallylamine can be easily obtained, for example, by heating allylamine hydrochloride in the presence of a radical polymerization initiator.

（式（７）中、Ｒ^５は水素原子又はメチル基を示し、Ｘは含窒素複素環基を示す。） Preferred as the soluble polymer containing a nitrogen-containing substituent used in the present invention is a water-soluble resin containing a monomer unit having a nitrogen-containing heterocyclic group represented by the following general formula (7).

(In formula (7), R ⁵ represents a hydrogen atom or a methyl group, and X represents a nitrogen-containing heterocyclic group.)

  X in the formula (7) is, for example, pyrrolyl group, imidazolyl group, pyrazolyl group, thiazolyl group, oxazolyl group, isoxazolyl group, pyridyl group, pyrazyl group, pyrimidyl group, pyridazyl group, triazolyl group, indolyl group, quinolyl group, A butyrolactam group, a caprolactam group, etc. are mentioned, However, Nitrogen-containing heterocyclic groups other than this may be sufficient. The bonding position of these heterocyclic groups is not particularly limited, and may be a nitrogen atom or a carbon atom.

（式（８）中、Ｒ^５及びＸは式（７）と同義である。） Such a soluble polymer containing a monomer unit having a nitrogen-containing heterocyclic group is, for example, a monomer having a nitrogen-containing heterocyclic group represented by the following general formula (8), or this monomer alone. It can be produced by polymerizing or copolymerizing a mixture with a monomer that does not contain a nitrogen atom to form a water-soluble polymer. This polymerization or copolymerization can be carried out by a method commonly used in the production of ordinary polymers or copolymers such as a solution polymerization method and a suspension polymerization method.

(In formula (8), R ⁵ and X have the same meanings as in formula (7).)

  Among the monomers represented by the formula (8), preferred are vinyl imidazole, vinyl imidazoline, vinyl pyridine, vinyl pyrrolidone, vinyl morpholine, and vinyl caprolactam, among which vinyl imidazole, vinyl imidazoline, and Vinylpyrrolidone is particularly preferred.

  Moreover, as a monomer which does not contain the nitrogen atom which forms a water-soluble polymer alone, for example, vinyl alcohol, acrylic acid or methacrylic acid hydroxyalkyl ester and the like can be mentioned. These monomers may be used alone or in combination of two or more.

  When copolymerizing a monomer having a nitrogen-containing heterocyclic group and a monomer that does not contain a nitrogen atom alone to form a water-soluble polymer, the mixing ratio is 10: 0 to 1: 9 by mass ratio. 9: 1 to 2: 8 are more preferable. Moreover, 500-15500 are preferable and, as for the mass mean molecular weight of a copolymer, 1000-50000 are more preferable. As this copolymer, a copolymer containing a cationic monomer is particularly preferable. Such copolymers are commercially available from, for example, BASF (product names “LUVITEC VPI55K72W” and “Sokalan HP56”), and polyvinylimidazoline is available from Tosoh Corporation. It is commercially available from the company.

  The content of the soluble polymer is preferably 0.1 mass ppm to 10 mass%, more preferably 0.5 mass ppm to 5 mass% in the resist surface modifier. By containing this soluble polymer, the surface of the photoresist film can be further modified to be hydrophilic, the wettability with respect to the developer can be improved, and the occurrence of development failure can be prevented.

  In addition, the resist surface modifier may be adjusted to an acidity of pH 6 or lower by adding an acid, if desired, and adjusted to a basicity of pH 8 or higher by adding an amine compound or a quaternary ammonium hydroxide. May be. By adding these, deterioration of the resist surface modifier with time can be prevented.

  Examples of such acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, oxalic acid, fumaric acid, maleic acid, phthalic acid, peracetic acid, sulfuric acid, trifluoroacetic acid, ascorbic acid and the like.

  Examples of the amine compound include monoethanolamine and 2- (2-aminoethoxy) ethanol. Examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, and 2-hydroxy. Examples thereof include ethyltrimethylammonium hydroxide, tetrapropylammonium hydroxide, methyltripropylammonium hydroxide, tetrabutylammonium hydroxide, and methyltributylammonium hydroxide.

  Such a resist surface modifier can modify the photoresist film surface to be hydrophilic. Therefore, by treating the photoresist film with this resist surface modifier before development, the wettability with respect to the developer can be improved and the development failure can be prevented.

[Resist pattern formation method]
The resist pattern forming method of the present invention includes a step of providing a photoresist film on a substrate, a step of selectively exposing a photoresist film through a mask pattern, and a photoresist film after exposure with the resist surface modifier of the present invention. And a step of developing the photoresist film after the treatment with the resist surface modifier. Hereinafter, each step of this resist pattern forming method will be described in detail.

  First, a photoresist film is provided on the substrate. A silicon wafer is generally used as the substrate, but is not particularly limited. In addition, a known photoresist composition for forming a photoresist film can be used, but the resist surface modifier of the present invention uses a resin having a fluorine atom or a siloxane bond in a resin skeleton as a base resin. This is particularly effective when using the above-described photoresist composition. In this step, a photoresist composition solution is applied onto a substrate such as a silicon wafer with a spinner or the like, and dried to form a photoresist film.

  Next, the photoresist film is selectively exposed through the mask pattern. In this step, the formed photoresist film is selectively exposed through a mask pattern to form a latent image, and then subjected to post-exposure heat treatment (PEB).

  Next, the exposed photoresist film is treated with the resist surface modifier of the present invention. In this step, a resist surface modifier is applied to the photoresist film surface with a spinner or the like and dried. By this treatment, the surface of the photoresist film is modified to be hydrophilic.

  Next, the photoresist film after the treatment with the resist surface modifier is developed. In this step, development processing is performed using an alkaline developer such as an aqueous solution of 1 to 10% by mass tetramethylammonium hydroxide. As described above, since the photoresist film surface is modified to be hydrophilic by treatment with the resist surface modifier of the present invention, the wettability of the developer is increased, and the development process can be performed satisfactorily. .

(Examples 1 to 3, Comparative Example 1)
[Evaluation of wettability of photoresist film to resist surface modifier]
An antireflection film-forming coating solution (Brewer, product name “ARC-29A”) is applied on an 8-inch silicon wafer, and heat-treated at 215 ° C. for 60 seconds to form an antireflection film having a thickness of 77 nm. Then, a photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd., product name “TARF-P7145”) is applied on the antireflection film and heat-treated at 145 ° C. for 60 seconds to form a 180 nm-thick photoresist film. It was. The photoresist film thus obtained was exposed through a mask pattern of a contact hole with a diameter of 130 nm using an exposure apparatus (product name “Nikon NSR-S302A” manufactured by Nikon Corporation), and then subjected to 60 at 110 ° C. For 2 seconds. On the other hand, lauryldimethylamine oxide (RDMAO) and didecylmethylamine oxide (DDMAO) were dissolved in deionized water with the composition shown in Table 1 to prepare a resist surface modifier. And the prepared resist surface modifier was dripped on the photoresist film | membrane, and the contact angle of the resist surface modifier was measured. The results are shown in Table 1.

  From the results shown in Table 1, the resist surface modifiers of Examples 1 to 3 containing lauryldimethylamine oxide and didecylmethylamine oxide were the resist surface modifiers of Comparative Example 1 containing no amine oxide compound. It was confirmed that the contact angle with respect to the photoresist film was smaller. Therefore, it is considered that the resist surface modifiers of Examples 1 to 3 spread efficiently over the photoresist film surface.

[Evaluation of wettability of photoresist film after surface modification with deionized water]
An antireflection film-forming coating solution (Brewer, product name “ARC-29A”) is applied on an 8-inch silicon wafer, and heat-treated at 215 ° C. for 60 seconds to form an antireflection film having a thickness of 77 nm. Then, a photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd., product name “TARF-P7145”) is applied on the antireflection film and heat-treated at 145 ° C. for 60 seconds to form a 180 nm-thick photoresist film. It was. The photoresist film thus obtained was exposed through a mask pattern of a contact hole with a diameter of 130 nm using an exposure apparatus (product name “Nikon NSR-S302A” manufactured by Nikon Corporation), and then subjected to 60 at 110 ° C. For 2 seconds. On the other hand, lauryl dimethylamine oxide (RDMAO) and didecylmethylamine oxide (DDMAO) were dissolved in deionized water at the composition shown in Table 2 to prepare a resist surface modifier. Then, the silicon wafer was dipped in the prepared resist surface modifier for 60 seconds and then dried. Thereafter, deionized water was dropped on the photoresist film, and the contact angle of deionized water was measured. The results are shown in Table 2.

  From the results shown in Table 2, in the photoresist film treated with the resist surface modifier of Examples 1 to 3 containing lauryldimethylamine oxide and didecylmethylamine oxide, the photoresist film of Comparative Example 1 containing no amine oxide compound was used. It was confirmed that the contact angle of deionized water was smaller than that of the photoresist film treated with the resist surface modifier. Therefore, it is considered that the developer reaches the surface of the photoresist film efficiently by treating the photoresist film with the resist surface modifier of Examples 1 to 3.

[Developability evaluation after surface modification with resist surface modifier]
An antireflection film-forming coating solution (Brewer, product name “ARC-29A”) is applied on an 8-inch silicon wafer, and heat-treated at 215 ° C. for 60 seconds to form an antireflection film having a thickness of 77 nm. Then, a photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd., product name “TARF-P7145”) is applied on the antireflection film and heat-treated at 145 ° C. for 60 seconds to form a 180 nm-thick photoresist film. It was. The photoresist film thus obtained was exposed through a mask pattern of a contact hole with a diameter of 130 nm using an exposure apparatus (product name “Nikon NSR-S302A” manufactured by Nikon Corporation), and then subjected to 60 at 110 ° C. For 2 seconds. On the other hand, lauryl dimethylamine oxide (RDMAO) and didecylmethylamine oxide (DDMAO) were dissolved in deionized water at the composition shown in Table 3 to prepare a resist surface modifier. Then, the prepared resist surface modifier was applied to the photoresist film surface at 2000 rpm for 7 seconds and then dried. Then, a resist pattern of a 130 nm contact hole was formed by developing for 60 seconds at 23 ° C. using an aqueous 2.38 mass% tetramethylammonium hydroxide solution. The repelling of the developer at this time was visually observed. Further, the pattern shape was observed with a scanning electron microscope, and a case where a good resist pattern was formed was evaluated as ◯, and a case where a resist pattern defect that was thought to be caused by a development failure was observed as x. The results are shown in Table 3.

From the results of Table 3, in the photoresist film treated with the resist surface modifier of Examples 1 to 3 containing lauryldimethylamine oxide and didecylmethylamine oxide, the photoresist film of Comparative Example 1 containing no amine oxide compound was used. Compared with a photoresist film treated with a resist surface modifier, no repelling of the developer was observed, and it was confirmed that a good resist pattern was formed.

Claims (11)

From an aqueous solution containing at least one amine oxide compound represented by the following general formulas (1) and (2) and at least one amine oxide compound represented by the following general formulas (3) and (4) Resist surface modifier.

(Equation (1), (2), R ¹ represents an alkyl or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, n and m represents an integer of 1 to 5. )

(In the formulas (3) and (4), R ² and R ³ each independently represent an alkyl group or hydroxyalkyl group having 8 to 20 carbon atoms which may be interrupted by an oxygen atom, and n represents 1 to 5 Indicates an integer)   99: 1 of at least one amine oxide compound represented by the general formulas (1) and (2) and at least one amine oxide compound represented by the general formulas (3) and (4) The resist surface modifier according to claim 1, which is contained at a mass ratio of ˜80: 20.   The resist surface modifier according to claim 1 or 2, wherein the aqueous solution contains water as a solvent.   The resist surface modifier according to any one of claims 1 to 3, wherein the aqueous solution uses a mixture of water and a water-miscible organic solvent as a solvent.   The resist surface modifier according to claim 4, wherein the water-miscible organic solvent is a monohydric or polyhydric alcohol organic solvent.   The resist surface modifier according to claim 4 or 5, wherein the amount of the water-miscible organic solvent in the solvent is 0.01 to 10% by mass.   The resist surface modifier according to any one of claims 1 to 6, wherein a content of the amine oxide compound in the aqueous solution is 0.1 mass ppm to 10 mass%.   Furthermore, the resist surface modifier of any one of Claim 1 to 7 which contains the compound chosen from polyoxyalkylene glycol and its alkyl ether in the said aqueous solution 1 mass ppm-5 mass%.   Furthermore, the resist surface modifier of any one of Claim 1 to 8 which contains 0.1 mass ppm-10 mass% of soluble polymers which contain a nitrogen atom in molecular structure in the said aqueous solution.   The resist surface modifier according to any one of claims 1 to 9, which is used as a resist surface treatment solution before a photoresist film development step. Providing a photoresist film on the substrate;
Selectively exposing the photoresist film through a mask pattern;
A step of treating the photoresist film after exposure with the resist surface modifier according to any one of claims 1 to 10,
Developing the photoresist film after treatment with the resist surface modifier;
A resist pattern forming method comprising: