JPWO2014171446A1 - Compositions used in self-assembled lithography processes - Google Patents

Abstract

The present invention includes a step of forming a first layer on an upper side of a substrate, a step of irradiating the first layer with radiation, and forming a first region and a second region having different polarities on the surface of the first layer, In a self-organized lithography process comprising a step of forming a second layer having a phase separation structure above the first region and the second region with a self-organizing material, and a step of removing a part of the second layer. A polysiloxane composition used for forming the first layer, which is a hydrolytic condensate of a silane compound represented by the following formula (i) and whose polarity changes due to the action of an acid, An acid generator that generates an acid and a solvent, and the solvent is an ether solvent, an ester solvent, or a polysiloxane composition containing an ether solvent and an ester solvent.

Description

  The present invention relates to a composition for use in a self-organized lithography process.

  In recent years, in the field of various electronic devices that require microfabrication, such as semiconductor devices, there is an increasing demand for higher density and higher integration of devices. Photolithography plays an important role in the formation of microcircuit patterns in such devices.

  In current photolithography, many reduction projection exposures are performed to form a minute pattern. Since the resolution in this reduced projection exposure is limited by the diffraction limit of light and is about one third of the wavelength of the light source, fine processing of about 100 nm becomes possible by using a short wavelength light source such as an excimer laser. Yes.

  However, along with the shortening of the wavelength of the light source, many problems to be solved have emerged, such as an increase in the size of the device, development of a lens in the wavelength region, and an increase in the cost of the device and the corresponding resist.

  On the other hand, as a method for easily forming a finer pattern, a method utilizing a microphase separation structure formed by a polymer capable of self-organization such as a block polymer has been reported. Such a method is called a self-organized lithography process and the following has been proposed. First, a photoreactive silane coupling agent is applied to the substrate surface to form a silicon-containing film, and a chemical pattern is formed by irradiating the surface of the silicon-containing film with light through a mask. Next, the self-assembled polymer is applied onto the chemical pattern, and heated, for example, so that self-assembly is phase-separated (self-assembled). At this time, the phase separation is promoted by the interaction between the chemical pattern and the self-assembled polymer. Thereafter, by removing some of the plurality of phases formed by phase separation, a fine pattern can be formed (Patent Documents 1 to 4).

JP-A-6-202343 JP 2003-321479 A JP-T-2005-502917 JP 2013-232501 A

Nature, 424, 411 (2003) Science, 308, 1442 (2005) Nano Letters, 5, 1379 (2005)

  However, the conventional self-assembled lithography process has a disadvantage that the chemical pattern and the self-assembled polymer do not sufficiently interact with each other and the phase separation property is not sufficient.

  The present invention has been made based on the above circumstances, and an object thereof is to provide a polysiloxane composition capable of forming a silicon-containing film capable of improving phase separation in a self-organized lithography process. is there.

（式（ｉ）中、Ｒ^Ａは、酸の作用により解離する結合を有する基である。Ｒ^Ｂは、水素原子又は１価の有機基である。Ｘは、ハロゲン原子又は−ＯＲ^Ｂである。ａは、１〜３の整数である。ｂは、０〜２の整数である。ただし、ａ＋ｂは１〜３の整数である。Ｒ^Ａが複数の場合、複数のＲ^Ａはそれぞれ同一でもよく、異なっていてもよい。Ｒ^Ｂが複数の場合、複数のＲ^Ｂはそれぞれ同一でもよく、異なっていてもよい。Ｘが複数の場合、複数のＸはそれぞれ同一でもよく、異なっていてもよい。）The polysiloxane composition of the present invention includes a step of forming a first layer on an upper side of a substrate, irradiating the first layer with radiation, and forming a first region and a second region having different polarities on the surface of the first layer. A self-organization comprising a forming step, a step of forming a second layer having a phase separation structure on the upper side of the first region and the second region with a self-organizing material, and a step of removing a part of the second layer A polysiloxane composition used for forming the first layer in a chemical lithography process, which is a hydrolytic condensate of a silane compound represented by the following formula (i) and whose polarity changes by the action of an acid A polysiloxane composition comprising an acid generator that generates an acid upon irradiation with radiation, and a solvent, wherein the solvent includes an ether solvent, an ester solvent, or an ether solvent and an ester solvent. .

(In the formula (i), R ^A is a group having a bond dissociated by the action of an acid. R ^B is a hydrogen atom or a monovalent organic group. X is a halogen atom or —OR ^B. .a is a is .b is an integer of 1 to 3, is an integer of 0-2. However, a + b If .R ^a is plural an integer of 1 to 3, in each of the plurality of ^{R a} same well, if may be different .R ^B is plural, each of the plurality of R ^B may be the same, if may be different .X is plural, the plurality of X may be each the same, be different Good.)

<Polysiloxane composition>
The polysiloxane composition of the present invention is a polysiloxane composition used in a self-assembled lithography process described later, and is a polysiloxane that is a hydrolysis condensate of a silane compound (hereinafter also referred to as “[A] polysiloxane”). , An acid generator (hereinafter also referred to as “[B] acid generator”), and a solvent (hereinafter also referred to as “[C] solvent”). The polysiloxane composition may further contain other components such as [D] a crosslinking accelerator, an acid diffusion controller, a surfactant, and an adhesion assistant as long as the effects of the invention are not impaired. .

[[A] polysiloxane]
[A] Polysiloxane is a hydrolysis-condensation product of a silane compound represented by the following formula (i), and its polarity is changed by the action of an acid. Since the polysiloxane composition contains [A] polysiloxane, the first region and the second region having different polarities can be formed in the first layer, and the mutual relationship between these regions and the second layer can be formed. By the action, phase separation of the second layer can be promoted.

In the above formula (i), R ^A is a group having a bond that is dissociated by the action of an acid. R ^B is a hydrogen atom or a monovalent organic group. X is a halogen atom or —OR ^B. a is an integer of 1 to 3. b is an integer of 0-2. However, a + b is an integer of 1-3. If R ^A is plural, each of the plurality of R ^A may be the same or may be different. If R ^B is plural, each of the plurality of R ^B may be the same or may be different. When X is plural, the plural Xs may be the same or different.

The group represented by ^RA above and having a bond dissociating by the action of an acid (hereinafter also referred to as “acid-dissociable group”) may be any group that can be dissociated by an acid generated from an acid generator [B]. That's fine. Dissociation of the acid dissociable group produces a carboxyl group, a phenolic hydroxyl group or an alcoholic hydroxyl group, and the polarity of [A] polysiloxane is increased.

As said ^RA , group represented by following formula (1) is mentioned, for example.

  In said formula (1), P is a single bond, a methylene group, a difluoromethylene group, a C2-C20 linear or branched alkylene group, a C6-C20 bivalent aromatic hydrocarbon group. Or a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. However, one part or all part of the hydrogen atom which the said alkylene group, aromatic hydrocarbon group, or alicyclic hydrocarbon group has may be substituted by the substituent. Q is —COO— or —O—. R is a monovalent organic group that is dissociated by an acid to generate a hydrogen atom.

  Examples of the linear or branched alkylene group having 2 to 20 carbon atoms represented by P include an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, and the like. Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenylene group and a naphthylene group. Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkylene groups such as cyclopropylene group, cyclobutylene group and cyclohexylene group; norbornane skeleton, tricyclodecane skeleton, tetracyclodecane skeleton, adamantane And divalent hydrocarbon groups having a bridged alicyclic skeleton such as a skeleton.

  Examples of the substituent capable of substituting some or all of the hydrogen atoms of the alkylene group include a fluorine atom and a linear or branched fluorinated alkyl group having 1 to 10 carbon atoms.

  Examples of the substituent capable of substituting part or all of the hydrogen atoms of the aromatic hydrocarbon group or alicyclic hydrocarbon group include a fluorine atom and a linear or branched fluorinated alkyl having 1 to 10 carbon atoms. Group, a methylene group, a difluoromethylene group, a linear or branched alkylene group having 2 to 10 carbon atoms, a linear or branched fluorinated alkylene group having 2 to 10 carbon atoms, and the like.

  Some of the carbon atoms of the alkylene group, aromatic hydrocarbon group or alicyclic hydrocarbon group are divalent atoms such as oxygen atoms and sulfur atoms, or divalent atomic groups such as -NH-. May be substituted.

  Examples of P include a single bond, a methylene group, a difluoromethylene group, a divalent hydrocarbon group having a tricyclodecane skeleton or a fluorinated product thereof, a divalent hydrocarbon group having an adamantane skeleton, a fluorinated product thereof, or a norbornane skeleton. And a divalent hydrocarbon group having a fluorinated group thereof or a fluorinated product thereof. In particular, a divalent hydrocarbon group having a norbornane skeleton or a fluorinated product thereof is preferable.

Examples of R include a linear or branched alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an alkyl-substituted cycloalkyl group having 4 to 12 carbon atoms, an adamantyl group having 10 to 14 carbon atoms, or Hydrocarbon groups such as alkyl-substituted adamantyl groups and aralkyl groups having 7 to 12 carbon atoms;
An alkylcarbonyl group, an alkoxycarbonyl group, a vinylcarbonyl group, an allylcarbonyl group, an aralkylcarbonyl group;
An organic group that forms an acetal structure by combining with an oxygen atom in the formula (1) such as an alkoxyalkyl group, an aralkyloxyalkyl group, or a cyclic ether group;
Examples thereof include a silyl group having one, two, or three types among an alkyl group, an aryl group, and an alkoxy group.

  R is preferably a t-butyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group, a 1-ethoxyethyl group, or a t-butyldimethylsilyl group.

  R in the case where Q is —COO— is preferably one in which the carbon atom bonded to Q among the atoms constituting R is bonded to three other carbon atoms. More preferably, the bonded carbon atom is bonded to a bulky group such as a cycloalkyl group, norbornyl group, adamantyl group or the like, and the carbon atom bonded to Q constitutes the above-mentioned bulky group. . When Q is —COO—, R has the above structure, so that R exhibits particularly excellent acid dissociability.

Examples of the monovalent organic group represented by R ^B include, for example,
Alkyl groups such as methyl, ethyl, propyl and butyl groups;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Chain hydrocarbon groups such as alkynyl groups such as ethynyl group, propynyl group, butynyl group;
A cycloalkyl group such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group;
An alicyclic hydrocarbon group such as a cycloalkenyl group such as a cyclopropenyl group, a cyclopentenyl group, a cyclohexenyl group, and a norbornenyl group;
Aryl groups such as phenyl, tolyl, xylyl, naphthyl and anthryl;
Examples thereof include aromatic hydrocarbon groups such as aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

  In addition, some of the carbon atoms of the monovalent organic group may be substituted with a divalent atom such as an oxygen atom or a sulfur atom, or a divalent atomic group such as —NH—. Furthermore, some or all of the hydrogen atoms of the monovalent organic group may be substituted with a halogen atom, a hydroxy group, a carboxy group, a nitro group, a cyano group, or the like.

  Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

X is preferably —OR ^B, more preferably an alkoxy group, still more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.

  As a, 1 or 2 is preferable and 1 is more preferable. As b, 0 or 1 is preferable, and 0 is more preferable. As a + b, 1 or 2 is preferable and 1 is more preferable.

([A] Preparation method of polysiloxane)
[A] The polysiloxane can be prepared by a known method using a silane monomer corresponding to the above formula (i).

[[B] acid generator]
[B] The acid generator is a compound that generates an acid upon irradiation with radiation, and generates an acid by being decomposed by heat or light energy upon irradiation with radiation. By this acid, the acid dissociable group of [A] polysiloxane is dissociated, and the polarity of [A] polysiloxane is improved. Examples of such [B] acid generators include thermal acid generators and photoacid generators. [B] Known acid generators can be used. Moreover, the [B] acid generator can be used individually by 1 type or in combination of 2 or more types.

[[C] solvent]
[C] The solvent contains an ether solvent, an ester solvent, or an ether solvent and an ester solvent, and dissolves [A] polysiloxane, [B] an acid generator and other optional components. When the polysiloxane composition contains the [C] solvent, the homogeneity and surface state of the first layer are improved. As a result, the interaction between the first layer and the second layer is improved, and the phase separation of the second layer is further promoted. Therefore, it is considered that the phase separation property is improved. [C] The solvent preferably contains water, and may further contain a solvent other than the ether solvent and the ester solvent. The other solvent is not particularly limited as long as it is a solvent capable of dissolving [A] polysiloxane and [B] acid generator, and examples thereof include alcohol solvents, ketone solvents, and amide solvents. Moreover, [C] solvent can be used individually by 1 type or in combination of 2 or more types.

  Examples of the ether solvent include dialiphatic ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether and diisoamyl ether; aromatic rings such as anisole, diphenyl ether and phenyl ethyl ether Ether solvents; cyclic ether solvents such as tetrahydrofuran, tetrahydropyran, dioxane and the like.

Examples of the ester solvent include methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, Carboxyl such as sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate Acid ester solvents;
Lactone solvents such as γ-butyrolactone and γ-valerolactone;
Polyhydric alcohol partial ether acetate solvents such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, and propylene carbonate.

Examples of the alcohol solvent include aliphatic monoalcohol solvents such as methanol, ethanol, iso-propyl alcohol, t-pentyl alcohol, 4-methyl-2-pentanol, and n-hexanol;
Alicyclic monoalcohol solvents such as cyclohexanol;
Polyhydric alcohol solvents such as ethylene glycol and 1,2-propylene glycol;
Examples thereof include polyhydric alcohol partial ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, and propylene glycol monoethyl ether.

Examples of the ketone solvent include aliphatic ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-butyl ketone, di-iso-butyl ketone, and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
2,4-pentanedione, acetonyl acetone, diacetone alcohol, acetophenone, methyl n-amyl ketone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as 1,3-dimethyl-2-imidazolidinone and N-methyl-2-pyrrolidone;
And chain amide solvents such as formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide and the like. It is done.

  As the ester solvent, a polyhydric alcohol partial ether acetate solvent is preferable, and propylene glycol monomethyl ether acetate is more preferable. [C] The ester solvent contained in the solvent is such that the interaction between the first layer and the second layer is further improved, and the phase separation of the second layer is improved. .

  [C] The total content of the ether solvent and the ester solvent in the solvent is preferably 50% by mass or more. Thus, when the total content of these solvents in the [C] solvent is 50% by mass or more, the above-described interaction is further improved, and the phase separation property of the second layer is further improved.

  [C] When the solvent further contains water, the content of water based on the [C] solvent is preferably 1% by mass or more, and more preferably 1% by mass or more and 5% by mass or less. Thus, since the [C] solvent contains water, the [A] polysiloxane is hydrated, so that the storage stability of the polysiloxane composition is improved. Moreover, since the hardening at the time of film-forming of the said 1st layer is accelerated | stimulated by presence of water, a precise | minute film | membrane can be obtained.

[Other optional ingredients]
([D] crosslinking accelerator)
[D] The crosslinking accelerator can promote the crosslinking reaction between or within the molecular chains of [A] polysiloxane when the radiation-sensitive polysiloxane-containing layer is formed from the polysiloxane composition. A compound. [D] The crosslinking accelerator is not particularly limited as long as it has the above-mentioned properties. For example, an acid, a base, a metal complex, a metal salt compound, an onium salt compound (excluding those corresponding to [B] acid generators) ) And the like. [D] The crosslinking accelerator may be used alone or in combination of two or more.

  Examples of the acid include hydrohalic acid such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrosulfuric acid, perchloric acid, hydrogen peroxide, carbonic acid, formic acid, acetic acid and other carboxylic acids; sulfonic acid such as benzenesulfonic acid; Examples thereof include phosphoric acid, heteropolyacid, and inorganic solid acid.

  Examples of the base include nitrogen-containing compounds; alkali metal compounds such as alkali hydroxides and alkali carbonates.

  Examples of the metal complex include chelate complexes composed of metal elements of Groups 2, 4, 5 and 13 of the periodic table and ligands such as β-diketone and ketoester.

  Examples of the metal salt compound include alkali metal salt compounds represented by the following formula (a).

In the above formula (a), M ⁺ is an alkali metal ion. X ^n- is at least one selected from monohydric or the group consisting of divalent or higher organic acid ions of the hydroxide ions and 1 to 30 carbon atoms. g is an integer of 1 or more. h is 0 or an integer of 1 or more. n is a valence of a hydroxide ion or an organic acid ion. g + h is the same as the sum of the valences of i hydroxide ions and organic acid ions.

  Examples of the alkali metal salt compound represented by the above formula (a) include hydroxide salts such as lithium, sodium, potassium, rubidium, and cesium, formate, acetate, propionate, decanoate, and stearate. Monovalent salts such as benzoates and phthalates; oxalates such as the above metals, malonates, succinates, glutarates, adipates, maleates, citrates, carbonates, etc. And monovalent or divalent salts thereof.

  Among these, as the [D] crosslinking accelerator, a nitrogen-containing compound and an onium salt compound are preferable from the viewpoint of more effectively increasing the molecular weight of the [A] polysiloxane.

  Examples of the nitrogen-containing compound include amine compounds, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds.

  Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′— Tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis ( 4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4- Aminophenyl) -2- (4-hydroxyphenyl) propane, , 4-bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ) Ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) And ethylenediamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine, and the like.

  Examples of the amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds, Nt-amyloxycarbonyl group-containing amino compounds, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N- Examples include methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, and isocyanuric acid tris (2-hydroxyethyl). Among these, Nt-butoxycarbonyl group-containing amino compounds and Nt-amyloxycarbonyl group-containing amino compounds are preferable, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl- 4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl-2-hydroxymethylpyrrolidine, Nt-butoxycarbonyl-2-phenylbenzimidazole are preferred.

  Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butylthiourea. Etc.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4 -Methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2. 2] octane and the like.

(Acid diffusion control agent)
The acid diffusion controller is a basic compound. The acid diffusion controller suppresses the diffusion of the acid purified from the [B] acid generator due to its basicity. As a result, the contrast of the polar pattern described later can be improved.

[Self-organized lithography process]
In the self-organized lithography process, a step of forming a first layer on the upper side of a substrate (hereinafter, also referred to as “first layer forming step”), irradiating the first layer with radiation, the surface of the first layer is formed. Forming a first region and a second region having different polarities (hereinafter also referred to as a “first layer exposure step”), and forming a second layer having a phase separation structure above the first region and the second region. The process mainly includes a step of forming (hereinafter also referred to as “second layer forming step”) and a step of removing part of the second layer (hereinafter also referred to as “removing step”). The self-assembled lithography process may further include a step of forming a guide pattern on the polar pattern (hereinafter, also referred to as “guide pattern forming step”) after the first layer exposure step.

(First layer forming step)
In this step, a radiation-sensitive polysiloxane-containing layer as a first layer is formed on the upper side of the substrate. Examples of the forming method include a method in which the polysiloxane composition is applied to the upper side of the substrate to form a coating film, and then the coating film is dried or cured by decompression, heating, or both. When heating is performed, the heating conditions are appropriately selected depending on the composition of the polysiloxane composition. Usually, it is 60 degreeC-350 degreeC, Preferably it is 150 degreeC-300 degreeC.

  A silicon substrate or the like is used as the substrate. If necessary, a different layer may be provided between the substrate and the radiation-sensitive polysiloxane-containing layer. Examples of such a layer include a coating layer such as aluminum, a layer made of an organic compound substantially not containing silicon atoms, and a layer containing non-radiation sensitive polysiloxane.

(First layer exposure process)
In this step, the radiation-sensitive polysiloxane-containing layer is irradiated with radiation. When the compound contained in the layer is a photoacid generator, laser light or the like is irradiated. When the compound is a thermal acid generator, energy rays or the like that can heat the surface of the layer are irradiated. Examples of usable radiation include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays and γ-rays; and charged particle beams such as electron beams and α-rays. Among these, far ultraviolet rays, extreme ultraviolet rays, and electron beams are preferable. Among deep ultraviolet rays, ArF excimer laser light (193 nm) and KrF excimer laser light (248 nm) are preferable, and ArF excimer laser light is more preferable.

  Irradiation is performed on a part of the radiation-sensitive polysiloxane-containing layer. Irradiation may be performed using a drawing apparatus such as an electron beam, or may be performed via a photomask. When the acid generated in the region irradiated with radiation changes the polarity of the polysiloxane, a region having a polarity different from that of the unirradiated region is formed. As a result, a layer having a polar pattern composed of an unirradiated region as a first region and an irradiated region as a second region on at least the surface of the layer (hereinafter also referred to as “polar pattern layer”). Is formed.

  In the present specification, the polar pattern refers to a chemical pattern formed without substantially changing the physical shape of the radiation-sensitive polysiloxane-containing layer before and after irradiation with radiation. The polar pattern in this specification does not include a physical pattern generated by a process aiming to change a physical shape as in a known photolithography process, or a chemical pattern accompanying the physical pattern. However, this definition is not intended to exclude all minute changes in the physical shape of the layer surface that are inevitably caused by chemical changes caused by irradiation of radiation.

  Irradiation can also be performed by an immersion exposure method. In this immersion exposure method, exposure is performed by filling the space between the exposure lens and the radiation-sensitive polysiloxane-containing layer with an immersion exposure solution. This immersion exposure liquid has a higher refractive index than air or inert gas. When an aqueous exposure liquid such as pure water is used as the immersion exposure liquid, it is preferable to form a water-repellent coating layer on the radiation-sensitive polysiloxane-containing layer. The water-repellent coating layer can be formed using, for example, a known resist upper layer forming composition for immersion exposure.

  Further, a coating layer other than the water-repellent coating layer may be formed on the radiation-sensitive polysiloxane-containing layer, and the radiation-sensitive polysiloxane-containing layer may be irradiated with radiation through this coating layer. Examples of such a coating layer include a known resist upper layer antireflection film.

  After exposure to radiation, post-exposure baking (PEB) can be performed to promote the reaction between the generated acid and the radiation-sensitive polysiloxane. The PEB temperature is, for example, 50 ° C to 180 ° C, preferably 70 ° C to 150 ° C, more preferably 75 ° C to 130 ° C, and particularly preferably 80 ° C to 100 ° C. The PEB time is, for example, 5 seconds to 600 seconds, and preferably 10 seconds to 180 seconds.

(Guide pattern forming process)
In this step, a guide pattern is arranged on the polar pattern. The guide pattern is also called a pre-pattern. When patterning by self-organization is collectively applied to a large area, a large number of microstructures having regularly arranged patterns may be randomly generated, and defects may be generated at the interfaces between the microstructures. By arranging the guide pattern on the substrate and defining the region, the region and direction in which the self-assembled pattern is generated can be defined in advance to control the phase separation. The guide pattern can be formed by any of physical factors such as unevenness and surface shape, and chemical factors such as changes in polarity and constituent materials. Generally, irregularities due to banks or the like are formed to constitute a guide pattern.

(Second layer forming step)
In this step, a self-assembled material layer as a second layer is formed above the polar pattern layer. Here, the self-organizing material is a general term for materials that spontaneously form an ordered pattern by phase separation. By applying this self-organizing material on the coating film and heating it as necessary, polymer structures having the same properties gather to form a phase-separated structure consisting of a plurality of phases in a self-aligning manner. .

  Examples of the self-assembling material include a block copolymer obtained by copolymerizing a monomer compound having one property and a monomer compound having different properties, and a composition containing a plurality of polymers having different properties from each other. Things are known. Of these, block copolymers are preferred. By using a block copolymer as the self-organizing material, a finer pattern can be easily obtained. Examples of the block copolymer include a styrene-methyl methacrylate block copolymer.

  As a method for forming the self-assembled material layer, for example, after applying the self-assembled material composition on the upper side of the polar pattern layer, pre-baking (PB) as necessary, and volatilizing the solvent in the coating film Examples of the method include heating (annealing) as necessary to promote phase separation. Here, the self-assembled material composition includes the self-assembled material and a solvent capable of dissolving the self-assembled material. When the water-repellent coating layer is formed on the radiation-sensitive polysiloxane-containing layer as described above, the water-repellent coating layer is removed before application of the self-organizing material composition.

  Examples of the method for applying the self-assembling material composition include spin coating, cast coating, and roll coating. As a film thickness of this coating film, it is 0.01 micrometer-1 micrometer, for example, Preferably it is 0.01 micrometer-0.5 micrometer.

  As said PB temperature, it is 30 to 200 degreeC, for example, Preferably it is 50 to 150 degreeC. The PB time is, for example, 5 seconds to 600 seconds, and preferably 20 seconds to 300 seconds.

  Examples of the annealing method include a method using an oven, a hot plate or the like. As said annealing temperature, it is 80 to 400 degreeC, for example, Preferably it is 100 to 350 degreeC. The annealing time is, for example, 10 seconds to 30 minutes, and preferably 30 seconds to 10 minutes.

(Removal process)
In this step, at least one of the plurality of phases constituting the self-organizing material layer is removed. Thereby, a fine pattern is obtained. Which phase of the plurality of phases is to be removed is selected according to the purpose of the process.

  Examples of the phase removal method include chemical etching and physical etching.

  The chemical etching is a method using a liquid as an etchant (chemical wet etching (wet development)). Examples of the etchant used for chemical etching include acids, alkaline aqueous solutions, and organic solvents. Examples of the acid include hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid and the like. Examples of the alkaline aqueous solution include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide (TMAH) aqueous solution and the like. Examples of the organic solvent include alcohol solvents, ester solvents, ketone solvents, ether solvents, amide solvents, hydrocarbon solvents, and the like.

The physical etching is, for example, a method using CF ₄ , O ₂ gas or the like as an etchant. Examples of the physical etching include reactive ion etching (RIE) such as chemical dry etching, sputter etching, and ion beam etching.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly to this Example. The measuring method of various physical property values is shown below.

[Mw and Mn measurement]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) under the following conditions.
Column: 2 Tosoh "G2000HXL", 1 "G3000HXL" and 1 "G4000HXL" Eluent: Tetrahydrofuran Column temperature: 40 ° C
Flow rate: 1.0 mL / min Detector: Differential refractometer Standard material: Monodisperse polystyrene

[Synthesis Example 1]
[Synthesis of Polysiloxane (A-1)]
1.28 g of oxalic acid was dissolved by heating in 12.85 g of water to prepare an aqueous oxalic acid solution, which was placed in a dropping funnel. Thereafter, 13.92 g of compound (M-1) (50 mol% with respect to the total mol of the compound), 35.93 g of compound (M-4) (50 mol% with respect to the total mol of the compound), and propylene glycol mono 35.90 g of ethyl ether was put into a flask, and a condenser tube and the above dropping funnel were installed in the flask. Next, the flask was heated to 60 ° C. in an oil bath, and then an aqueous oxalic acid solution was slowly dropped from the dropping funnel and reacted at 60 ° C. for 4 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then placed in an evaporator to remove the methanol produced by the reaction to obtain 175.0 g of a resin solution containing polysiloxane (A-1). The solid content concentration (content ratio of polysiloxane (A-1)) in the resin solution was 10.0% by mass. Moreover, the weight average molecular weight (Mw) of polysiloxane (A-1) was 2,000.

[Synthesis Examples 2 to 11]
[Synthesis of Polysiloxane (A-2) to (A-9), (CA-1) and (CA-2)]
Polysiloxanes (A-2) to (A-9), (CA-1) and (CA-2) were the same as in Synthesis Example 1 except that the types and amounts of the compounds used were as described in Table 1. ) Was synthesized. Table 1 also shows the Mw of these polysiloxanes.

  The compounds used for the synthesis of polysiloxanes (A-1) to (A-9), (CA-1) and (CA-2) are shown below.

[Example 1]
[Preparation of Polysiloxane Composition (J-1)]
[A] 2 parts by mass of a resin solution containing 10% by mass of (A-1) as polysiloxane, [B] 0.1 part by mass of (B-1) as an acid generator, [D] as a crosslinking accelerator (D-1) 0.02 parts by mass, and [C] solvent (C-1) 70 parts by mass, (C-2) 25 parts by mass and (C-3) 2.88 parts by mass. The mixed solution was filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation sensitive resin composition (J-1).

  Each component used for the synthesis | combination of polysiloxane composition (J-1)-(J-17) and (DJ-1)-(DJ-4) is shown below.

[[B] acid generator]
B-1: Compound represented by the following formula (B-1)

[[C] solvent]
C-1: Propylene glycol monomethyl ether acetate C-2: Propylene glycol monoethyl ether C-3: Water

[[D] Cross-linking accelerator]
D-1: Compound represented by the following formula (D-1)

[Preparation of Self-Assembly Material Composition]
Diblock copolymer comprising polystyrene block and polymethyl methacrylate block (styrene unit in diblock copolymer is 50% by mass, methyl methacrylate unit is 50% by mass, Mw of diblock copolymer is 80,000) ) Was dissolved in propylene glycol methyl ether acetate to give a 1% by mass solution. This solution was filtered through a membrane filter having a pore diameter of 200 nm to prepare a self-organizing material composition.

<Evaluation>
[Formation and exposure of radiation-sensitive polysiloxane-containing layer]
An organic underlayer film having a thickness of 105 nm was formed by spin-coating a composition for forming an organic underlayer film (“ARC66” from Nissan Chemical Co., Ltd.) on a 12-inch silicon wafer and performing PB at 210 ° C. for 60 seconds. On this organic underlayer film, the polysiloxane compositions of Examples and Comparative Examples were spin-coated, PB was performed at 210 ° C. for 60 seconds, and then cooled at 23 ° C. for 60 seconds, whereby a radiation sensitive polysiloxane having a film thickness of 30 nm was obtained. A siloxane-containing layer was formed.

  Next, using the ArF immersion exposure apparatus (S610C, manufactured by NIKON), the radiation-sensitive poly-siloxane is passed through a mask having a mask size for forming a 42 nm line / 84 nm pitch under the optical conditions of NA: 1.30 and Dipole. The siloxane-containing layer was exposed to form a polar pattern. After exposure, PEB was performed at 100 ° C. for 60 seconds on the hot plate of the coating / developing apparatus, and then cooled at 23 ° C. for 30 seconds.

[Formation of self-assembled material layer]
Thereafter, the self-assembling material composition was spin-coated on the radiation-sensitive polysiloxane-containing layer after exposure, and heated at 210 ° C. for 10 minutes to cause phase separation.

[Phase separation structure by self-organization]
About the phase-separation structure by self-organization, the self-organization material layer in an Example and a comparative example was observed using length measuring SEM (Hitachi "S-4800"), and the following references | standards evaluated. The evaluation results are shown in Table 3.
A: A clear phase separation can be confirmed.
B: There is a portion where phase separation is incomplete.

  As shown in Table 3, when the polysiloxane composition of the example was used, the phase separation of the self-assembled material layer formed thereon was clear. On the other hand, when the polysiloxane composition of the comparative example was used, there was a portion where the phase separation of the self-assembled material layer was incomplete. Thus, it turns out that the polysiloxane composition of an Example can improve the phase-separation property of a self-organization material layer compared with the thing of a comparative example.

  The polysiloxane composition of the present invention can form a silicon-containing film capable of improving phase separation in a self-organized lithography process. Therefore, the polysiloxane composition can be suitably used for pattern formation in semiconductor device production or the like, which is expected to become increasingly finer in the future.

Claims (7)

Forming a first layer on the upper side of the substrate;
Irradiating the first layer with radiation to form first and second regions having different polarities on the surface of the first layer;
In a self-organized lithography process, comprising: a step of forming a second layer having a phase separation structure above the first region and the second region with a self-organizing material; and a step of removing a part of the second layer. , A polysiloxane composition used to form the first layer,
A polysiloxane which is a hydrolyzed condensate of a silane compound represented by the following formula (i) and whose polarity changes by the action of an acid;
Contains an acid generator that generates acid upon irradiation, and a solvent.
The polysiloxane composition in which the solvent includes an ether solvent, an ester solvent, or an ether solvent and an ester solvent.

(In the formula (i), R ^A is a group having a bond dissociated by the action of an acid. R ^B is a hydrogen atom or a monovalent organic group. X is a halogen atom or —OR ^B. .a is a is .b is an integer of 1 to 3, is an integer of 0-2. However, a + b If .R ^a is plural an integer of 1 to 3, in each of the plurality of ^{R a} same well, if may be different .R ^B is plural, each of the plurality of R ^B may be the same, if may be different .X is plural, the plurality of X may be each the same, be different Good.)   The polysiloxane composition according to claim 1, wherein the ester solvent is a polyhydric alcohol partial ether acetate solvent.   The polysiloxane composition according to claim 1 or 2, wherein the solvent further contains water, and the content of the water based on the solvent is 1% by mass or more.   The polysiloxane composition according to claim 3, wherein a content of the water based on the solvent is 1% by mass or more and 5% by mass or less.   The polysiloxane composition according to claim 1, wherein the self-assembled material contains a block copolymer.   The polysiloxane according to claim 1 or 5, wherein the self-organized lithography process further includes a step of forming a coating layer on the first layer, and the irradiation with the radiation is performed through the coating layer. Composition. The polysiloxane composition according to claim 6, wherein in the self-organized lithography process, the irradiation with the radiation is performed by an immersion exposure process.