JP5966779B2 - Pattern formation method - Google Patents

Description

  The present invention relates to a pattern forming method, a pattern, and a semiconductor element.

  With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, pattern miniaturization in the lithography process is required. At present, it is possible to form a fine pattern with a line width of about 90 nm using, for example, an ArF excimer laser, but further fine pattern formation will be required in the future.

  In response to the above requirements, several pattern forming methods using so-called self-organized phase separation structures that spontaneously form ordered patterns have been proposed. For example, a method of forming an ultrafine pattern by self-assembly using a block copolymer obtained by copolymerizing a monomer compound having one property and a monomer compound having a different property is known (special feature). JP 2008-149447 A, JP 2002-519728 A, JP 2003-218383 A). According to this method, by annealing the composition containing the block copolymer, polymer structures having the same properties tend to gather together, so that a pattern can be formed in a self-aligned manner. Also known is a method of forming a fine pattern by self-organizing a composition containing a plurality of polymers having different properties (US Patent Application Publication No. 2009/0214823, Japanese Patent Application Laid-Open No. 2010-58403). reference).

  However, the pattern obtained by the conventional pattern formation method by self-organization has a large line width roughness (LWR) and its variation (Critical Dimension Uniformity: CDU), and has insufficient lithography characteristics. There is an inconvenience.

JP 2008-149447 A Japanese translation of PCT publication No. 2002-519728 JP 2003-218383 A US Patent Application Publication No. 2009/0214823 JP 2010-58403 A

  The present invention has been made based on the above circumstances, and an object thereof is to provide a pattern forming method capable of forming a fine pattern having excellent lithography characteristics using LWR and CDU as indices. .

The invention made to solve the above problems is
(1) a step of forming a phase separation film on a substrate using a composition containing two or more kinds of polymers (hereinafter also referred to as “polymer composition”); and (2) a part of the phase separation film. A pattern forming method including a step of removing a phase,
The pattern forming method is characterized in that at least one of the two or more polymers is a fluorine atom-containing polymer.

  Since the polymer composition has at least one fluorine atom-containing polymer, phase separation is facilitated. Therefore, according to the pattern formation method, the LWR and CDU values are reduced, and a pattern having excellent lithography characteristics can be formed. it can.

（式（１）中、Ｒ^１は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^２は、炭素数１〜６のアルキル基又は炭素数４〜２０の脂環式基である。但し、上記アルキル基及び脂環式基が有する水素原子の少なくとも１つは、フッ素原子又はフッ素原子を有する置換基で置換されている。
式（２）中、Ｒ^３は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^４は、（ｋ＋１）価の連結基である。Ｘは、フッ素原子を有する２価の連結基である。Ｒ^５は、水素原子又は有機基である。ｋは、１〜３の整数である。但し、ｋが２以上の場合、複数のＸ及びＲ^５は、それぞれ同一でも異なっていてもよい。） The fluorine atom-containing polymer contains at least one structural unit selected from the group consisting of the structural unit (I) represented by the following formula (1) and the structural unit (II) represented by the following formula (2). It is preferable to have.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. However, at least one of the hydrogen atoms of the alkyl group and the alicyclic group is substituted with a fluorine atom or a substituent having a fluorine atom.
In Formula (2), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁴ is a (k + 1) -valent linking group. X is a divalent linking group having a fluorine atom. R ⁵ is a hydrogen atom or an organic group. k is an integer of 1 to 3. However, when k is 2 or more, the plurality of X and R ⁵ may be the same or different. )

  When the fluorine atom-containing polymer has at least one structural unit selected from the group consisting of the structural unit (I) and the structural unit (II), the pattern obtained by the pattern forming method can be an LWR and a CDU. The value is further reduced and the lithography properties are excellent.

（式（３）中、Ｒ^６は、炭素数１〜６のアルキル基である。Ｒ^７は、フッ素原子又は有機基である。ｐは１〜３の整数である。但し、Ｒ^６及びＲ^７が複数となる場合、複数のＲ^６及びＲ^７はそれぞれ同一でも異なっていてもよい。また、Ｒ^７の少なくとも１つはフッ素原子又はフッ素原子を有する基である。） The fluorine atom-containing polymer is preferably a hydrolysis condensate of a compound represented by the following formula (3) (hereinafter also referred to as “fluorine atom-containing silane compound”).

(In the formula (3), R ⁶ is an alkyl group having 1 to 6 carbon atoms. R ⁷ is a fluorine atom or an organic group. P is an integer of 1 to 3. However, R ⁶ and R When a plurality of ⁷ are present, the plurality of R ⁶ and R ⁷ may be the same or different from each other, and at least one of R ⁷ is a fluorine atom or a group having a fluorine atom.)

  When the fluorine atom-containing polymer is a hydrolyzed condensate of the fluorine atom-containing silane compound, the pattern obtained by the pattern forming method further reduces the LWR and CDU values and is excellent in lithography properties.

  At least one of the two or more polymers is preferably a styrenic polymer. Since the styrenic polymer has low compatibility with other polymers, when at least one of the two or more kinds of polymers contained in the polymer composition is a styrenic polymer, the polymer composition forms a phase separation structure. It becomes easy. For this reason, the pattern obtained by the pattern forming method further reduces LWR and CDU, and has superior lithography characteristics.

  It is preferable to remove part of the phase separation membrane by wet development. By removing part of the phase separation film by wet development in the pattern forming method, a pattern having excellent process cost and lithography characteristics with reduced LWR and CDU can be formed.

Before step (1) above,
(0-1) a step of forming a lower layer film on the substrate; and (0-2) a step of forming a pre-pattern having a side surface substantially perpendicular to the substrate on the lower layer film,
The phase separation membrane in the step (1) is formed in a region on the lower layer film separated by the prepattern, and the prepattern is removed in addition to a part of the phase separation membrane in the step (2). It is preferable that the pattern forming method be used.

  It is preferable to remove the prepattern by wet development. By removing the pre-pattern by wet development, the process cost is excellent, and the pattern obtained by the pattern forming method has excellent lithography characteristics with reduced LWR and CDU.

  The present invention includes a pattern formed by the pattern forming method. Since the pattern is excellent in lithography characteristics using LWR and CDU as indices, it is preferably used in the manufacture of semiconductor elements and the like.

  The present invention also includes a semiconductor element having the pattern. Since the pattern has excellent lithography characteristics using LWR and CDU as indices, a semiconductor element having the pattern can improve the degree of circuit integration and the recording density.

  According to the pattern forming method of the present invention, it is possible to form a pattern having excellent lithography characteristics using LWR and CDU as indices.

In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a lower layer film | membrane on a board | substrate. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a pre pattern on a lower layer film. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after apply | coating a polymer composition to the area | region on the lower layer film | membrane divided by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a phase-separation film in the area | region on the lower layer film | membrane divided by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after removing the one part phase and pre pattern of a phase-separation film | membrane.

<Pattern formation method>
The pattern forming method of the present invention comprises:
(1) A pattern forming method including a step of forming a phase separation film on a substrate using a composition containing two or more kinds of polymers, and (2) a step of removing a part of the phase of the phase separation film. In the pattern forming method, at least one of the two or more polymers is a fluorine atom-containing polymer.
Further, before the step (1), (0-1) a step of forming a lower layer film on the substrate, and (0-2) a pre-pattern having a side surface substantially perpendicular to the substrate on the lower layer film. Forming a phase separation film in the step (1) in a region on the lower layer film separated by the prepattern, and in the step (2), a part of the phase separation film In addition to the above phase, it is preferable to remove the prepattern.
Further, after the step (2), it is preferable to further include (3) a step of etching the substrate using the formed pattern as a mask. Hereinafter, each process and a polymer composition are explained in full detail. Each process will be described with reference to FIGS.

[(0-1) Step]
This step is a step of forming a lower layer film on the substrate using the lower layer film forming composition. Thereby, as shown in FIG. 1, a substrate with a lower layer film in which the lower layer film 102 is formed on the substrate 101 can be obtained, and the phase separation film is formed on the lower layer film 102. The phase separation structure of the phase separation film changes depending on the interaction with the lower layer film 102 in addition to the interaction between the polymers contained in the polymer composition. Control becomes possible. Furthermore, the multi-layer process using the lower layer film 102 as a mask can further improve the etching resistance of the pattern (mask) obtained.

  As the substrate 101, a conventionally known substrate such as a silicon wafer, a wafer coated with aluminum, a GaN substrate, a GaP substrate, or the like can be used.

  Moreover, as said composition for lower layer film formation, the material etc. which are marketed by brand names, such as ARC66 (made by Brewer Science), NFC HM8005 (made by JSR), NFC CT08 (made by JSR), etc. are used, for example. Can do.

  The formation method of the lower layer film 102 is not particularly limited. For example, a coating film formed by applying a known method such as a spin coating method on the substrate 101 is cured by exposure and / or heating. can do. Examples of radiation used for this exposure include visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ-rays, molecular beams, and ion beams. Moreover, the temperature at the time of heating a coating film is although it does not specifically limit, It is preferable that it is 90-550 degreeC, 90-450 degreeC is more preferable, and 90-300 degreeC is further more preferable. The thickness of the lower layer film 102 is not particularly limited, but is preferably 50 to 20,000 nm, and more preferably 70 to 1,000 nm. The lower layer film 102 preferably includes an SOC (Spin on carbon) film.

[(0-2) Step]
In this step, as shown in FIG. 2, a prepattern 103 is formed on the lower layer film 102 using a composition for forming a prepattern. The pre-pattern 103 controls the phase separation of the polymer composition, and a desired fine pattern can be formed. That is, among the polymers contained in the polymer composition, a polymer having a high affinity with the side surface of the prepattern forms a phase along the prepattern, and a polymer having a low affinity forms a phase at a position away from the prepattern. . Thereby, a finer pattern than before can be formed. Further, the phase separation structure of the polymer composition can be finely controlled by the material, length, thickness, shape and the like of the prepattern.

  As a method for forming the pre-pattern 103, a method similar to a known resist pattern forming method can be used. Further, as the pre-pattern forming composition, a conventional resist film-forming composition can be used. As a specific method for forming the pre-pattern 103, for example, a chemical amplification resist composition containing a radiation-sensitive acid generator and a resin having a group that is dissociated by an acid and becomes a polar group is used. A resist film is formed by coating on the top. Next, exposure is performed by irradiating a desired region of the resist film with radiation through a mask having a specific pattern. Examples of the radiation include ultraviolet rays, far ultraviolet rays, X-rays, and charged particle beams. Among these, far ultraviolet rays represented by ArF excimer laser and KrF excimer laser are preferable, and ArF excimer laser is more preferable. Moreover, as exposure, liquid immersion exposure etc. can be used suitably. Next, post-exposure baking (PEB) is performed, and development is performed using a developer such as an alkali developer, so that a desired pre-pattern 103 can be formed. In addition, the formation method of the pre pattern which develops using an organic solvent instead of an alkali developing solution, and obtains a negative pattern can also be used suitably.

  Note that the surface of the pre-pattern 103 may be subjected to a hydrophobic treatment or a hydrophilic treatment. As a specific treatment method, a hydrogenation treatment by exposing to hydrogen plasma for a certain period of time can be cited. By increasing the hydrophobicity or hydrophilicity of the surface of the pre-pattern 103, self-assembly of the polymer composition can be promoted.

[(1) Process]
In this step, as shown in FIGS. 3 and 4, a polymer composition containing two or more kinds of polymers including at least one fluorine atom-containing polymer is applied to a region on the lower layer film 102 separated by the pre-pattern 103. In this step, the coating film 104 is formed, and the phase separation film 105 having a phase separation structure having an interface substantially perpendicular to the substrate 101 is formed on the lower layer film 102 formed on the substrate 101. The formation of the phase separation membrane 105 follows the principle described in the report by Walheim et al. (Macromolecules, vol. 30, pp. 4995-5003, 1997). That is, by applying a solution containing two or more kinds of polymers incompatible with each other on a substrate and performing annealing or the like, polymers having the same properties accumulate to form an ordered pattern spontaneously. Self-organization can be promoted. Thereby, a phase separation structure having an interface substantially perpendicular to the substrate 101 is formed. This phase separation structure is preferably formed along the pre-pattern, and the interface formed by phase separation is more preferably substantially parallel to the side surface of the pre-pattern. For example, when the affinity between the prepattern 103 and the fluorine atom-containing polymer is high, a phase of the fluorine atom-containing polymer is formed along the prepattern 103 (105b), and the polymer incompatible with the fluorine atom-containing polymer is It is formed in the part farthest from the side surface of the pre-pattern, that is, the central part of the region delimited by the pre-pattern (105a), and forms a lamellar phase separation structure in which lamellar (plate-like) phases are alternately arranged. . In addition, a desired fine pattern can be obtained by precisely controlling the obtained phase separation structure by the blending ratio of each polymer, pre-pattern, lower layer film, and the like. The details of the polymer composition will be described later.

  Although the method in particular of apply | coating the said polymer composition on a board | substrate and forming the coating film 104 is not restrict | limited, For example, the method etc. which apply | coat the said polymer composition used by spin coating methods etc. are mentioned. Accordingly, the polymer composition is filled between the prepatterns 103 on the lower layer film 102.

  Examples of the annealing method include a method of heating at a temperature of 80 ° C. to 200 ° C. with an oven, a hot plate or the like. The annealing time is usually 10 seconds to 30 minutes, preferably 30 seconds to 5 minutes. As a film thickness of the phase separation film 105 obtained by this, 0.1 nm-500 nm are preferable, and 0.5 nm-100 nm are more preferable.

[(2) Process]
As shown in FIGS. 4 and 5, this step is a step of removing a part of the polymer phase 105 a and / or the pre-pattern 103 in the phase separation structure of the phase separation film 105. A method in which a part of the polymer phase 105a and / or the pre-pattern 103 is removed by development using the difference in solubility between phases separated by self-assembly is preferable. In addition, a part of the polymer phase 105a and / or the pre-pattern 103 can be removed by an etching process using the difference in the etching rate of each phase. FIG. 5 shows a state after removing a part of the polymer phase 105a and the prepattern 103 in the phase separation structure.

As a method for removing a part of the polymer phase 105a or the pre-pattern 103 in the phase separation structure of the phase separation film 105 by development, alkali development or organic solvent development used for development in a known resist composition. Etc. are used.
Further, as a method for removing a part of the polymer phase 105a or the pre-pattern 103 in the phase separation structure of the phase separation film 105, for example, reactive ion etching (RIE) such as chemical dry etching or chemical wet etching; Known methods such as physical etching such as sputter etching and ion beam etching may be used. Of these, reactive ion etching (RIE) is preferable, and among these, chemical dry etching using CF ₄ , O ₂ gas, etc., and chemical wet etching (wet development) using a liquid etching solution such as hydrofluoric acid are used. More preferred. In chemical dry etching, in general, an oxygen-based gas is often used to remove a carbon-based polymer, and a fluorine-based gas is often used to remove a silicon-based polymer.

[(3) Process]
This step is a step of patterning by etching the lower layer film and the substrate after the step (2), using a pattern made of a part of the polymer phase 105b of the remaining phase separation film as a mask. After the patterning on the substrate is completed, the phase used as a mask is removed from the substrate by dissolution treatment or the like, and a finally patterned substrate (pattern) can be obtained. As the etching method, the same method as in step (2) can be used, and the etching gas and the etching solution can be appropriately selected depending on the material of the lower layer film and the substrate. For example, when the substrate is a silicon material, a mixed gas of chlorofluorocarbon gas and SF ₄ or the like can be used. When the substrate is a metal film, a mixed gas of BCl ₃ and Cl ₂ or the like can be used. In addition, the semiconductor element which has the said pattern is used suitably for LED, a solar cell, etc.

<Polymer composition>
The polymer composition used in the present invention is a composition containing two or more polymers, and at least one of the two or more polymers is a fluorine atom-containing polymer. When at least one of the two or more kinds of polymers is a fluorine atom-containing polymer, the polymer composition can be easily phase-separated, and the lithography characteristics of the resulting pattern can be excellent.

  These two or more types of polymers are not particularly limited as long as they are phase-separated into two or more phases, but a combination of a fluorine atom-containing polymer and a fluorine atom-free polymer is preferred. When the two or more kinds of polymers are a combination of a fluorine atom-containing polymer and a fluorine atom-free polymer, phase separation of the polymer composition is more likely to occur.

  The polymer composition may contain a thermal acid generator, a radiation-sensitive acid generator, and a surfactant as suitable components in addition to two or more polymers including at least one fluorine atom-containing polymer. Moreover, you may contain arbitrary components, such as a solvent, unless the effect of this invention is impaired. Hereinafter, the fluorine atom-containing polymer, other polymers, thermal acid generator, radiation sensitive acid generator, surfactant and solvent will be described in detail.

<Fluorine atom-containing polymer>
The fluorine atom-containing polymer contained in the polymer composition is not particularly limited as long as it is a polymer containing fluorine atoms, but the (meth) acrylic polymer, siloxane polymer, styrene polymer, etc. have hydrogen atoms. It is preferable that a part or all of is a polymer substituted with fluorine atoms, and (meth) acrylic polymers and siloxane polymers are more preferable. The (meth) acrylic polymer is at least one structure selected from the group consisting of the structural unit (I) represented by the above formula (1) and the structural unit (II) represented by the above formula (2). More preferred are polymers having units. Moreover, as a siloxane type polymer, the hydrolysis-condensation product of the fluorine atom containing silane compound represented by the said Formula (3) is further more preferable. Hereinafter, the (meth) acrylic polymer and the siloxane polymer will be described in detail.

<(Meth) acrylic polymer>
The (meth) acrylic polymer as the fluorine atom-containing polymer used in the present invention preferably has at least one structural unit selected from the group consisting of the structural unit (I) and the structural unit (II). In addition, unless the effect of this invention is impaired, you may have other structural units other than structural unit (I) and structural unit (II). Moreover, the said fluorine atom containing (meth) acrylic-type polymer may have 1 type, or 2 or more types of each structural unit. Hereinafter, each structural unit will be described in detail.

[Structural unit (I)]
The structural unit (I) is represented by the above formula (1). In said formula (1), R < ¹ > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is a C 1-6 alkyl group or a C 4-20 alicyclic group. However, at least one of the hydrogen atoms of the alkyl group and the alicyclic group is substituted with a fluorine atom or a substituent having a fluorine atom.

  Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

  Examples of the alicyclic group having 4 to 20 carbon atoms include a cyclopentyl group, a cyclopentylpropyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctylmethyl group.

  Examples of the monomer that gives the structural unit represented by the above formula (1) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Perfluoro n-propyl (meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, Perfluorocyclohexyl (meth) acrylate, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5 -Octafluoro) pentyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octa (Luolo) hexyl (meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3, 4,4,4-heptafluoro) penta (meth) acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10, 10-heptadecafluoro) decyl (meth) acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro) hexyl (meth) acrylate and the like. Of these, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate is preferred.

  In the (meth) acrylic polymer as the fluorine atom-containing polymer in the present invention, the content of the structural unit (I) is preferably 20 mol% to 100 mol%, more preferably 30 mol% to 80 mol%. By making the content rate of structural unit (I) into the said specific range, LWR and CDU of the pattern obtained can be made into the outstanding value.

[Structural unit (II)]
The structural unit (II) is represented by the above formula (2). In the above formula (2), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁴ is a (k + 1) -valent linking group. X is a divalent linking group having a fluorine atom. R ⁵ is a hydrogen atom or an organic group. k is an integer of 1 to 3. However, when k is 2 or 3, the plurality of X and R ⁵ may be the same or different.

In the above formula (2), the (k + 1) -valent linking group represented by R ⁴ is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms or an alicyclic group having 3 to 30 carbon atoms. A group, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or one or more selected from the group consisting of an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group And a group formed by combining with a group. The (k + 1) -valent linking group may have a substituent.

  Examples of the hydrocarbon group having 1 to 30 carbon atoms include groups obtained by removing (k + 1) hydrogen atoms from hydrocarbon groups such as methane, ethane, propane, butane, pentane, hexane, heptane, decane, icosane and triacontane. Is mentioned.

Examples of the alicyclic group having 3 to 30 carbon atoms include monocyclic saturated hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, and ethylcyclohexane;
Monocyclic unsaturated hydrocarbons such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene;
Bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1.1 ^3,7 ] decane, Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] polycyclic saturated hydrocarbons such as dodecane and adamantane;
Bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3.3.1.1 ^3,7 ] decene, Tetracyclo [6.2.1.1 ^3,6 . And a group obtained by removing (k + 1) hydrogen atoms from a polycyclic hydrocarbon such as 0 ^2,7 ] dodecene.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include (k + 1) hydrogen atoms from benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene, and the like. Excluded groups and the like.

  In the above formula (2), examples of the divalent linking group having a fluorine atom represented by X include a C 1-20 divalent linear hydrocarbon group having a fluorine atom. Among these, groups represented by the following formulas (X-1) to (X-6) are preferable, and groups represented by the following formulas (X-1) and (X-2) are more preferable.

In the above formula (2), examples of the organic group represented by R ⁵ include a hydrocarbon group having 1 to 30 carbon atoms, an alicyclic group having 3 to 30 carbon atoms, and an aromatic hydrocarbon having 6 to 30 carbon atoms. And a group formed by combining a group or these groups with one or more groups selected from the group consisting of an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group.

  As a monomer which gives the structural unit represented by the above formula (2), for example, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester , (Meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-tri Fluoromethyl-2-hydroxy-5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2 -{[5- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester and the like. That. Of these, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester is preferred.

  In the (meth) acrylic polymer as the fluorine atom-containing polymer in the present invention, the content of the structural unit (II) is preferably 30 mol% to 100 mol%, and 50 mol% to 100 mol%. Is more preferable. By making the content rate of structural unit (II) into the said specific range, the LWR and CDU of the pattern obtained can be made into the outstanding value.

<Siloxane polymer>
The fluorine atom-containing siloxane polymer used in the present invention is preferably a hydrolysis condensate of a fluorine atom-containing silane compound represented by the above formula (3).

In the above formula (3), ^{R 6} is an alkyl group having 1 to 6 carbon atoms. R ⁷ is a fluorine atom or an organic group. p is an integer of 1 to 3. However, if R ⁶ and R ⁷ is plural, R ⁶ and R ⁷ may be the same as or different from each other. At least one of R ⁷ is a fluorine atom or a group having a fluorine atom.

In the above formula (3), the alkyl group having 1 to 6 carbon atoms represented by R ^6, for example a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and the like.

In the above formula (3), examples of the organic group represented by R ⁷ include a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic group having 3 to 20 carbon atoms, and an aromatic group having 6 to 20 carbon atoms. Examples thereof include a hydrocarbon group or a group formed by combining these groups.

  Examples of the fluorine atom-containing silane compound represented by the above formula (3) include fluorotrichlorosilane, fluorotrimethoxysilane, fluorotriethoxysilane, fluorotri-n-propoxysilane, fluorotri-i-propoxysilane, fluorotri -N-butoxysilane, fluorotri-sec-butoxysilane, 2- (trifluoromethyl) ethyltrichlorosilane, 2- (trifluoromethyl) ethyltrimethoxysilane, 2- (trifluoromethyl) ethyltriethoxysilane, 2 -(Trifluoromethyl) ethyltri-n-propoxysilane, 2- (trifluoromethyl) ethyltri-i-propoxysilane, 2- (trifluoromethyl) ethyltri-n-butoxysilane, 2- (trifluoromethyl) ethyltri- sec Butoxysilane, 2- (perfluoro-n-hexyl) ethyltrichlorosilane, 2- (perfluoro-n-hexyl) ethyltrimethoxysilane, 2- (perfluoro-n-hexyl) ethyltriethoxysilane, 2- ( Perfluoro-n-hexyl) ethyltri-n-propoxysilane, 2- (perfluoro-n-hexyl) ethyltri-i-propoxysilane, 2- (perfluoro-n-hexyl) ethyltri-n-butoxysilane, 2- (Perfluoro-n-hexyl) ethyltri-sec-butoxysilane, 2- (perfluoro-n-octyl) ethyltrichlorosilane, 2- (perfluoro-n-octyl) ethyltrimethoxysilane, 2- (perfluoro- n-octyl) ethyltriethoxysilane, 2- (perfluoro- -Octyl) ethyltri-n-propoxysilane, 2- (perfluoro-n-octyl) ethyltri-i-propoxysilane, 2- (perfluoro-n-octyl) ethyltri-n-butoxysilane, 2- (perfluoro- n-octyl) ethyltri-sec-butoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] dichlorosilane, (methyl) [2- (perfluoro-n-octyl) ethyl] dimethoxysilane, ( Methyl) [2- (perfluoro-n-octyl) ethyl] dimethoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] di-n-propoxysilane, (methyl) [2- (per Fluoro-n-octyl) ethyl] di-i-propoxysilane, (methyl) [2- (perfluoro-n-octyl Silane compounds such as (til) ethyl] di-n-butoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] di-sec-butoxysilane, and pentafluorophenylpropyltrimethoxysilane. Of these, pentafluorophenylpropyltrimethoxysilane is preferred.

  In the fluorine atom-containing siloxane-based polymer in the present invention, the content of the hydrolytic condensate of the fluorine atom-containing silane compound is preferably 30 mol% to 100 mol%, and preferably 50 mol% to 100 mol%. More preferred. The fluorine atom-containing polymer may be a hydrolysis condensate of a plurality of types of fluorine atom-containing silane compounds.

<Other polymers>
Examples of the polymer other than the fluorine atom-containing polymer in the two or more kinds of polymers include (meth) acrylic polymers, siloxane polymers, styrene polymers, polyvinyl acetal polymers, polyurethane polymers, polyurea polymers, and polyimide polymers. Examples thereof include polymers, polyamide-based polymers, epoxy-based polymers, novolac-type phenol polymers, and polyester-based polymers. Of these, (meth) acrylic polymers, siloxane polymers, and styrene polymers are preferred. The polymer may be a homopolymer synthesized from one type of monomer compound or a copolymer synthesized from a plurality of types of monomer compounds.

  Examples of the (meth) acrylic polymer include polymethacrylic acid, polymethylmethacrylic acid, polyacrylic acid, and polymethylacrylic acid.

Examples of monomer compounds used to synthesize these polymers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic. Isobutyl acid, n-octyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, dimethylaminoethyl (meth) acrylate (Meth) acrylic acid esters such as;
Examples include (meth) acrylic monomers such as acrylonitrile, methacrylamide, glycidyl methacrylate, N-methylol acrylamide, N-methylol methacrylamide, and 2-hydroxyethyl acrylate.

  Examples of the siloxane polymer include polysiloxane and polydimethylsiloxane.

  Examples of monomer compounds used to synthesize these polymers include tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra -Sec-butoxysilane, trichlorosilane, trimethoxysilane, triethoxysilane, tri-n-propoxysilane, tri-i-propoxysilane, tri-n-butoxysilane, tri-sec-butoxysilane and the like.

  Examples of the styrenic polymer include homopolymers such as polystyrene, styrene copolymers such as styrene-butadiene copolymers, styrene-acrylonitrile copolymers, and styrene-acrylonitrile-butadiene copolymers.

  Examples of monomer compounds used for synthesizing these polymers include styrene, o-methylstyrene, ethylstyrene, p-methoxystyrene, p-phenylstyrene, 2,4-dimethylstyrene, and pn-octyl. Styrene, pn-decyl styrene, pn-dodecyl styrene, etc. are mentioned.

  At least one of the two or more polymers contained in the polymer composition is preferably a styrenic polymer. Since the styrenic polymer has particularly low compatibility with fluorine atom-containing polymers such as (meth) acrylic polymers and siloxane polymers, the polymer composition is easily phase-separated by containing the styrenic polymer. Moreover, since a styrene-type polymer is excellent in etching resistance, it can ensure the difference of an etching rate with the other polymer contained simultaneously. As a result, the LWR and CDU of the obtained pattern can be further reduced.

  Examples of the combination of two or more incompatible polymers contained in the polymer composition include, for example, a combination of a fluorine atom-containing (meth) acrylic polymer and a fluorine atom-free styrene polymer, or a fluorine atom-containing siloxane polymer. And a combination of a fluorine atom-free styrene polymer and the like. Among these, a combination of fluorine atom-containing polymethyl methacrylate and fluorine atom-free polystyrene, or a combination of fluorine atom-containing polysiloxane and fluorine atom-free polystyrene is preferable.

<Polymer synthesis method>
[Method of synthesizing polymer by polymerization reaction]
The (meth) acrylic polymer or the like can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable solvent using a radical polymerization initiator. For example, a method of dropping a solution containing a monomer and a radical initiator into a reaction solvent or a solution containing the monomer to cause a polymerization reaction, a solution containing the monomer, and a solution containing the radical initiator Separately, a method of dropping a reaction solvent or a monomer-containing solution into a polymerization reaction, a plurality of types of solutions containing each monomer, and a solution containing a radical initiator, It is preferable to synthesize by a method such as a method of dropping it into a reaction solvent or a solution containing a monomer to cause a polymerization reaction.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. These solvents may be used alone or in combination of two or more.

  Although the reaction temperature in the said polymerization should just be suitably determined according to the kind of radical initiator, it is 40 to 150 degreeC normally, and 50 to 120 degreeC is preferable. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionitrile) and the like. Two or more of these initiators may be mixed and used.

  The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

[Polymer synthesis method by condensation reaction]
Siloxane polymers and the like can be synthesized by hydrolytic condensation of monomer compounds. For example, a siloxane-based polymer can be synthesized by hydrolyzing or hydrolyzing / condensing a silane compound or a mixture of a plurality of silane compounds, preferably in the presence of a suitable organic solvent, water and a catalyst.

  As a weight average molecular weight (Mw) by gel permeation chromatography (GPC) of each polymer, 1,000-100,000 are preferable, 1,000-50,000 are more preferable, 1,000-30,000 are Further preferred. By setting the Mw of each polymer within the specific range, it is possible to reduce the LWR and CDU of the obtained pattern.

  As ratio (Mw / Mn) of Mw of a polymer and a number average molecular weight (Mn), it is 1-5 normally, 1-3 are preferable and 1-2 are more preferable. By setting Mw / Mn to such a specific range, the LWR and CDU of the obtained pattern can be reduced.

  Mw and Mn are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, manufactured by Tosoh Corporation), flow rate 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1.0 mass%, sample A value measured by gel permeation chromatography (GPC) using a monodisperse polystyrene as a standard using a differential refractometer as a detector under the analysis conditions of an injection amount of 100 μL and a column temperature of 40 ° C.

<Acid generator>
The polymer composition used in the present invention can further increase the LWR and CDU of the resulting pattern by further containing an acid generator such as a thermal acid generator or a radiation sensitive acid generator. . Known compounds can be used as the thermal acid generator and radiation sensitive acid generator. In addition, these compounds may be used individually by 1 type, and may be used in combination of 2 or more types.
The content of the acid generator is preferably 0.01% by mass to 20% by mass, more preferably 0.01% by mass to 10% by mass, based on the total solid content of the polymer composition, and 0.01% by mass to 5%. More preferred is mass%.

<Surfactant>
The polymer composition used in the present invention may further contain a surfactant. The application | coating property to a board | substrate etc. can be improved because the polymer composition of this invention contains surfactant.

  A known compound can be used as the surfactant, and the content thereof is 0.0001 parts by mass with respect to the total polymer composition from the viewpoint of ensuring the effect of reducing the LWR and CDU of the resulting pattern. -5 parts by mass is preferable, and 0.0001-1 part by mass is more preferable. In addition, these surfactants may be used individually by 1 type, and may be used in combination of 2 or more types.

<Solvent>
The polymer composition of the present invention usually contains a solvent. As said solvent, the solvent similar to the solvent illustrated in the synthesis | combining method of the said polymer can be mentioned, for example. Of these, propylene glycol monomethyl ether acetate, butyl acetate, and 2-heptanone are preferable. These solvents may be used alone or in combination of two or more.

<Method for Preparing Polymer Composition>
The polymer composition used in the pattern forming method can be prepared, for example, by mixing components such as two or more kinds of polymers and acid generators in a predetermined ratio in the solvent. The polymer composition can be prepared and used in a state dissolved or dispersed in a suitable solvent.

<Pattern>
The pattern of the present invention is formed by the pattern forming method. For this reason, the pattern is excellent in lithography characteristics using LWR and CDU as indices, and thus is suitably used in the manufacture of semiconductor elements and the like. In addition, the said pattern refers to things, such as a patterned film | membrane and a board | substrate obtained by the said pattern formation method. The description in the pattern forming method can be applied to the pattern.

<Semiconductor element>
The semiconductor element of the present invention has the pattern. Since the semiconductor element has the pattern and can improve the degree of integration and recording density of the circuit, it is preferably used for electronic devices such as LEDs and solar cells.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The measuring method of each physical property value is shown below.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) using Tosoh GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under the following conditions.
Eluent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[Low molecular weight component content]
The content (mass%) of the low molecular weight component (component of molecular weight less than 1,000) of the polymer is determined by using Inertsil ODS-25 μm column (4.6 mmφ × 250 mm) manufactured by GL Sciences, using high performance liquid chromatography (HPLC). Was measured under the following conditions.
Eluent: Acrylonitrile / 0.1% by mass phosphoric acid aqueous solution Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer

[ ¹³ C-NMR analysis]:
¹³ C-NMR analysis was performed using JNM-EX400 manufactured by JEOL Ltd. and DMSO-d ₆ as a measurement solvent. The content rate of each structural unit in a polymer was computed from the area ratio of the peak corresponding to each structural unit in the spectrum obtained by < ¹³ > C-NMR.

<Polymer synthesis>
The monomers used for polymer synthesis are shown below.

[Synthesis Example 1]
46.95 g of methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester (M-2) giving structural unit (II), and initiator (2,2 A monomer solution was prepared by dissolving 6.91 g of '-azobis- (methyl 2-methylpropionate)) in 100 g of isopropanol. Meanwhile, 50 g of isopropanol was charged into a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using the dropping funnel, the monomer solution prepared in advance was added dropwise over 2 hours. After completion of dropping, the reaction was further continued for 2 hours. Then, it cooled to 30 degrees C or less, and obtained the polymer solution. The obtained polymer solution was concentrated to 150 g and then transferred to a separatory funnel. The separatory funnel was charged with 50 g of methanol and 600 g of n-hexane to separate them, and the lower layer liquid was recovered. This lower layer solution was diluted with isopropanol to 100 g, and again transferred to a separatory funnel. 50 g of methanol and 600 g of n-hexane were put into a separatory funnel and separated, and then the lower layer solution was recovered. The polymer (A-1) was obtained by removing the solvent. Mw of polymer (A-1) was 10,000, Mw / Mn was 1.7, and the content of low molecular weight components was 1.0% by mass.

[Synthesis Example 2]
A monomer solution was prepared by dissolving 25.0 g of 2,2-azobis (methyl 2-methylisopropionate) in 25.0 g of methyl ethyl ketone. On the other hand, methacrylic acid (1,1,1-3,3,3-hexafluoro-2-propyl) ester which gives structural unit (I) to a 2,000 mL three-necked flask equipped with a thermometer and a dropping funnel 195.4 g of (M-1), 104.6 g of compound (M-2) giving structural unit (II), and 575.0 g of methyl ethyl ketone were added and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using the dropping funnel, the monomer solution prepared in advance was added dropwise over 5 minutes and stirred for 6 hours. Then, it cooled to 30 degrees C or less, and obtained the copolymer liquid. The obtained copolymer solution was concentrated to 600 g and transferred to a separatory funnel. The separatory funnel was charged with 193 g of methanol and 1,542 g of n-hexane and separated, and then the lower layer solution was recovered. After 117 g of methyl ethyl ketone and 1,870 g of n-hexane were added to the recovered lower layer solution and separated, the lower layer solution was recovered. Further, 93 g of methanol, 77 g of methyl ethyl ketone and 1,238 g of n-hexane were added to the recovered lower layer solution to separate them, and then the lower layer solution was recovered. The polymer (A-2) was obtained by removing the solvent. Mw of the polymer (A-2) was 9,000, Mw / Mn was 1.5, and the low molecular weight component content was 1.0% by mass. Moreover, as a result of ¹³ C-NMR analysis, the content of the structural unit derived from the compound (M-1) in the polymer (A-2): the content of the structural unit derived from the compound (M-2) was 60.5. Mole%: 39.5 mol%.

[Synthesis Example 3]
Into a nitrogen-substituted quartz three-necked flask, 2.14 g of a 20% by mass aqueous maleic acid solution and 139.6 g of ultrapure water were added and heated to 65 ° C. Next, a solution in which 25.7 g of tetramethoxysilane (M-3), 50.2 g of pentafluorophenylpropyltrimethoxysilane (M-4) which is a fluorine atom-containing silane compound, and 85.2 g of propylene glycol monomethyl ether acetate was mixed. The solution was added dropwise to the reaction vessel over 1 hour and stirred at 85 ° C. for 4 hours. The reaction solution was returned to room temperature, and 200 g of propylene glycol monomethyl ether acetate was added. Subsequently, after concentrating until solid content concentration became 40 mass%, the polymer solution (A-3) of 1.3 mass% was obtained by adding propylene glycol monomethyl ether acetate again. Mw of the polymer (A-3) was 2,500.

<Creation of evaluation board>
A 12-inch silicon wafer was spin-coated with an organic underlayer film (ARC66, manufactured by Brewer Science) using CLEAN TRACK ACT8 (manufactured by Tokyo Electron), and then baked at 205 ° C. to form a lower layer having a thickness of 77 nm. A film was formed. After spin coating of the formed underlayer film with a resist composition for ArF containing a methacrylic acid ester-based acid dissociable group-containing polymer, a radiation sensitive acid generator, an acid diffusion controller, and an organic solvent, PB (120 (C, 60 seconds) to form a resist film having a thickness of 60 nm. Using an ArF immersion exposure apparatus (NSR S610C, manufactured by Nikon Corporation), exposure was performed through a mask pattern under optical conditions of NA; 1.30, CrossPole, and σ = 0.777 / 0.78. Thereafter, PEB was performed at 115 ° C. for 60 seconds, and then developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, washed with water, and dried to obtain a prepattern (40 nm line / 90 nm Pitch). Subsequently, the prepattern was irradiated with ultraviolet light of 254 nm at 150 mJ / cm ^{2 and then} baked at 170 ° C. for 5 minutes to obtain an evaluation substrate.

<Pattern formation>
Other polymers used for forming the pattern are shown below.

<Other polymers>
A-4: Poly (1- (4-hydroxyphenyl) ethyl silsesquioxane-lane- (1- (phenyl) ethyl silsesquioxane (poly (HMBS ₅₀ -r-MBS ₅₀ ))
A-5: Polystyrene (5.5k)

[Example 1]
A 1.3 mass% propylene glycol monomethyl ether acetate solution in which the polymer (A-1) and the polymer (A-5) were mixed at a mass ratio of 40:60 was prepared. The obtained solution was filtered through a filter having a pore size of 0.2 μm to obtain a polymer composition (J-1). The composition was spin-coated (3,000 rpm / 30 seconds) on the evaluation substrate and annealed on a hot plate at 120 ° C. for 60 seconds. Then, after making cyclohexane into a developing solution and immersing for 60 seconds, the polymer (A-5) was removed by drying cyclohexane by a nitrogen flow, and the pattern was formed. The line width (CD), line width roughness (LWR), and line width variation (CDU) were evaluated by observing with a length measuring SEM (S9220, manufactured by Hitachi).

[Examples 2-3 and Comparative Example 1]
A pattern was formed in the same manner as in Example 1 except that the polymer shown in Table 1 was used.

<Evaluation>
Various physical properties of the resist pattern formed as described above were evaluated as follows. The results are shown in Table 1.

[Critical Dimension (CD)]
A total of 30 line widths formed by the pattern forming method were measured, and an average value of the total 30 measured values was calculated as CD (nm). A length measuring SEM (S9220, manufactured by Hitachi, Ltd.) was used for measuring the line width.

[Critical Dimension Uniformity (CDU)]
A total of 30 line widths formed by the above pattern formation method were measured, the average deviation of the total 30 measured values was calculated, and the value obtained by multiplying by 3 was defined as CDU (nm). The case where the value of this CDU was 2.5 (nm) or less was evaluated as good. A length measuring SEM (S9220, manufactured by Hitachi, Ltd.) was used for measuring the line width.

[Line Width Roughness (LWR)]
The line pattern obtained by the pattern formation method was observed from above the pattern using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, CG4000). A total of 50 line widths were measured at arbitrary points, and a value calculated by measuring the measurement variation as 3 sigma was defined as LWR (nm). The case where the value of LWR was 3.5 (nm) or less was judged as good. A length measuring SEM (S9220, manufactured by Hitachi, Ltd.) was used for measuring the line width.

  As shown in Table 1, it was found that the pattern formed by the resist pattern forming method of the present invention has reduced LWR and CDU and excellent lithography characteristics.

  According to the pattern forming method of the present invention, LWR and CDU are reduced, and a fine pattern having excellent lithography characteristics can be formed. Therefore, the pattern formed by the pattern forming method of the present invention can be suitably used for various electronic devices such as semiconductor devices and liquid crystal devices.

101. Substrate 102. Underlayer film 103. Pre-pattern 104. Coating film 105. Phase separation membrane 105a. Polymer phase 105b. Polymer phase

Claims (4)

(1) A pattern forming method including a step of forming a phase separation film on a substrate using a composition containing two or more kinds of polymers, and (2) a step of removing a part of the phase separation film. There,
The two or more polymer over comprises a combination of a fluorine atom-containing polymer and a fluorine atom-free styrene polymer,
The fluorine atom-containing polymer is a (meth) acrylic polymer or a siloxane polymer,
The (meth) acrylic polymer is at least one structure selected from the group consisting of a structural unit (I) represented by the following formula (1) and a structural unit (II) represented by the following formula (2): Have units,
The siloxane polymer is a hydrolysis condensate consisting of only a silane compound represented by the following formula (3) or a mixture of a plurality of silane compounds containing a silane compound represented by the following formula (3). The pattern formation method characterized by these.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 4 to 20 carbon atoms. However, at least one of the hydrogen atoms of the alkyl group and the alicyclic group is substituted with a fluorine atom or a substituent having a fluorine atom.
In Formula (2), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁴ is a (k + 1) -valent linking group. X is a divalent linking group having a fluorine atom. R ⁵ is a hydrogen atom or an organic group. k is an integer of 1 to 3. However, when k is 2 or more, the plurality of X and R ⁵ may be the same or different. )

(In the formula (3), R ⁶ is an alkyl group having 1 to 6 carbon atoms. R ⁷ is a fluorine atom or an organic group. P is an integer of 1 to 3. However, R ⁶ and R When a plurality of ⁷ are present, the plurality of R ⁶ and R ⁷ may be the same or different from each other, and at least one of R ⁷ is a fluorine atom or a group having a fluorine atom.) The pattern forming method according to claim 1 , wherein a part of the phase separation film is removed by wet development. Before step (1) above,
(0-1) a step of forming a lower layer film on the substrate; and (0-2) a step of forming a pre-pattern having a side surface substantially perpendicular to the substrate on the lower layer film,
The phase separation membrane in the step (1) is formed in a region on the lower layer film separated by the prepattern, and the prepattern is removed in addition to a part of the phase separation membrane in the step (2). The pattern forming method according to claim 1 or 2 . The pattern forming method according to claim 3 , wherein the prepattern is removed by wet development.

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