JP6027758B2 - Composition and pattern forming method - Google Patents

Description

  The present invention relates to a method of forming a pattern using the phase separation structure of a block copolymer, and a composition containing the block copolymer used in the method.

In recent years, with the further miniaturization of large-scale integrated circuits (LSIs), a technique for processing more delicate structures is required. In response to such a demand, a method of forming a finer pattern using a phase separation structure formed by self-assembly of a block copolymer in which mutually incompatible blocks are bonded to each other is disclosed. (For example, refer to Patent Document 1).
As the block copolymer forming the phase separation structure, a block copolymer having a polymethacrylic acid ester derivative polymer block and a polystyrene derivative polymer block is widely used. More specifically, a block copolymer having a polymethyl methacrylate block and a polystyrene block is mentioned (see Patent Document 1).

  In order to use the phase separation of the block copolymer, it is essential to form the self-assembled nanostructure formed by the microphase separation only in a specific region and arrange it in a desired direction. In order to realize these position control and orientation control, methods such as grapho epitaxy for controlling the phase separation pattern by the guide pattern and chemical epitaxy for controlling the phase separation pattern by the difference in the chemical state of the substrate have been proposed. (For example, refer nonpatent literature 1).

JP 2008-36491 A

Proceedings of SPIE, Volume 7637, 76370G-1 (2010). J. et al. Photopolym. Sci. Technol. , Vol20, No5, 2007, Pattern Transfer of Laterally Aligned Lamellar Domains of Dibbit Copolymers

  Usually, when the layer containing the block copolymer is phase-separated, annealing by heat treatment or solvent treatment is performed. As the annealing treatment, a heat treatment is common because the operation is simple. However, when a normal block copolymer as described in the above patent document is used, it is necessary to perform an annealing process at a high temperature of about 250 ° C. in order to obtain a good phase separation structure. Therefore, since it is necessary to use a material that can withstand the high temperature for the support, the degree of freedom in selecting the support material is low, and improvement of the process has been demanded. In addition, when processing is performed at high temperatures, the burden on the processing equipment becomes large, and therefore materials that can be improved and annealed at low temperatures are required.

In addition, the support on which the layer containing the block copolymer is formed may include an antireflection film, a neutralization film, the above-described guide pattern, etc. in addition to the layer containing the block copolymer.
When the annealing process is performed at a high temperature, the antireflection film, the neutralization film, and the guide pattern are similarly required to have heat resistance, and there is a problem that it is difficult to optimize the respective materials. In particular, since the guide pattern is often formed of a resist film, it is required that the annealing process can be performed at a temperature lower than the softening point of the resist film that forms the guide pattern.

  In addition, it is possible to lower the annealing temperature by increasing the annealing time, but there is a problem that long-time annealing is not preferable from the viewpoint of productivity. For example, Patent Document 1 describes that the annealing treatment was performed at a relatively low temperature of 155 ° C. and Non-Patent Document 2 at 195 ° C., but the treatment time was 16 hours, both of which are very long. Not practical. Therefore, there is a need for a novel block copolymer composition and pattern formation method that can be annealed at a low temperature and in a short time.

  The present invention has been made in view of the above circumstances, and utilizes a block copolymer phase-separated structure capable of forming a good pattern even when annealing is performed at a relatively low temperature for a relatively short time. It is an object of the present invention to provide a method for forming a pattern and a composition containing a block copolymer used in the method.

As a result of extensive investigations, the present inventors have made it possible to lower the glass transition point of the layer containing the block copolymer at a low temperature by incorporating a specific compound into the composition containing the block copolymer. It was found that a good pattern could be obtained in a short time even when it was carried out, and the present invention was completed.
Specifically, a first aspect of the present invention comprises a block copolymer in which a plurality of types of blocks linked together, and benzyl glycol, glycerol, one or more alcohols selected from the group of phenyl diglycol and benzyl diglycol 2- It is a composition containing at least one organic solvent selected from the group consisting of heptanone, propylene glycol monomethyl ether acetate, ethyl lactate and γ-butyrolactone .
According to a second aspect of the present invention, there is provided a step of forming a layer containing a block copolymer on a support using the composition of the first aspect, and then phase-separating the layer containing the block copolymer; And a step of selectively removing a phase composed of at least one block out of a plurality of types of blocks constituting the block copolymer in the layer containing the copolymer.

  According to the present invention, a good pattern can be formed even when annealing is performed at a relatively low temperature for a relatively short time.

It is a schematic process drawing explaining the example of an embodiment of the pattern formation method of the present invention.

[Composition]
The composition of the present invention has a block copolymer (A) in which plural types of blocks are bonded (hereinafter referred to as “component (A)”), a vapor pressure at 20 ° C. of 0.05 hPa or less, and a freezing point of 25. A compound (B) (hereinafter referred to as “component (B)”) having a temperature not higher than ° C. and an organic solvent (C) that does not correspond to the component (A) (hereinafter referred to as “component (C)”). To do.

<(A) component; block copolymer>
In the present invention, the block copolymer is a polymer in which a plurality of partial constituent components (blocks) in which only the same type of structural units are bonded. There may be two types of blocks constituting the block copolymer, or three or more types. In the present invention, the plural types of blocks constituting the block copolymer are not particularly limited as long as they are combinations in which phase separation occurs, but are preferably combinations of blocks that are incompatible with each other. Moreover, it is preferable that the phase which consists of at least 1 type block in the multiple types of block which comprises a block copolymer is a combination which can be selectively removed easily rather than the phase which consists of other types of block.

As the component (A), after the block P _A that are not selectively removed in step, the block P _A and P _A block other than the block incompatible (hereinafter sometimes referred to as "P _B block". ) Are combined. P _A block, P _B block may be a one, respectively, it may be two or more types. If P _B block is two or more, each of the block P _B together may be incompatible with each other, it may be compatible.

Specifically, as the component (A), for example,
A block of a structural unit derived from styrene or a derivative thereof, and a block of a structural unit derived from acrylic acid or an ester thereof in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, A block copolymer to which is bound;
A block copolymer obtained by combining a block of a structural unit derived from styrene or a derivative thereof and a block of a structural unit derived from siloxane or a derivative thereof;
A block of a structural unit derived from an alkylene oxide and a block of a structural unit derived from acrylic acid or an ester thereof in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent And block copolymers.

As “styrene or a derivative thereof”, a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, or a hydrogen atom bonded to a benzene ring may be substituted with a substituent other than a hydroxyl group. Good styrene (hereinafter, styrene in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent is referred to as “α-substituted styrene”. The styrene in which the position is not substituted and the α-substituted styrene are collectively referred to. And "(α-substituted) styrene").
(Α-Substitution) As a substituent for substituting the hydrogen atom bonded to the carbon atom at the α-position of styrene or a derivative thereof, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms is preferable. An alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is more preferable, and a hydrogen atom or a methyl group is most preferable in terms of industrial availability.
The alkyl group as a substituent at the α-position is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert group. -A butyl group, a pentyl group, an isopentyl group, a neopentyl group, etc. are mentioned.
Specific examples of the halogenated alkyl group as the substituent at the α-position include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α-position” are substituted with a halogen atom. It is done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.

  Specific examples of styrene or derivatives thereof include, for example, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, 2,4, Examples include 6-trimethylstyrene, 4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxystyrene, and the like. .

“Acrylic acid ester” is a compound in which the hydrogen atom at the carboxy group terminal of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
The hydrogen atom bonded to the carbon atom at the α-position is bonded to the carbon atom at the α-position of the acrylic acid which may be substituted with a substituent (hereinafter sometimes referred to as “(α-substituted) acrylic acid”) or an ester thereof. The substituent is the same as the substituent bonded to the α-position carbon atom of the above (α-substituted) styrene or its derivative.
Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
Specific examples of the organic group include a hydrocarbon group which may have a substituent.

  Examples of the (α-substituted) acrylate ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, and (meth). Nonyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, anthracene (meth) acrylate, glycidyl (meth) acrylate, 3,4- (meth) acrylic acid 3,4- Examples thereof include epoxy cyclohexyl methane and propyltrimethoxysilane (meth) acrylate.

Examples of the siloxane derivative include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, methylphenylsiloxane, and the like.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, isopropylene oxide, and butylene oxide.

Among these, as the component (A), it is preferable to use a block copolymer in which a block of a structural unit derived from styrene or a derivative thereof and a block of a structural unit derived from (meth) acrylic acid ester are combined. .
Specifically, polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer, polystyrene-polyethyl methacrylate block copolymer, polystyrene- (poly-t-butyl methacrylate) block copolymer, polystyrene-polymethacrylic acid block copolymer, polystyrene-poly. Examples thereof include a methyl acrylate block copolymer, a polystyrene-polyethyl acrylate block copolymer, a polystyrene- (poly-t-butyl acrylate) block copolymer, a polystyrene-polyacrylic acid block copolymer, and it is particularly preferable to use a PS-PMMA block copolymer. .
After phase separation of the layer containing the PS-PMMA block copolymer, the layer made of PMMA is selectively removed by performing etching treatment (decomposition treatment and developer treatment) on the layer. That is, in this case, PS is a block _{P A,} PMMA is _{P B} block.

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of each block constituting the component (A) is not particularly limited as long as it can cause phase separation. , 5000 to 500000 are preferable, 5000 to 400000 are more preferable, and 5000 to 300000 are more preferable.
Further, the dispersity (Mw / Mn) of the block copolymer is preferably 1.0 to 3.0, more preferably 1.0 to 1.5, and still more preferably 1.0 to 1.2. In addition, Mn shows a number average molecular weight.
The shape of each phase of the obtained phase separation structure can be adjusted by appropriately adjusting the component ratio and the mass average molecular weight of each block constituting the component (A).

<(B) component; compound>
The composition of the present invention contains a component (B) having a vapor pressure at 20 ° C. of 0.05 hPa or less and a freezing point of 25 ° C. or less. Here, “vapor pressure at 20 ° C.” refers to the pressure of the vapor phase in equilibrium with the liquid phase or solid phase at 20 ° C.
By using a compound having a specific vapor pressure as the component (B), it becomes possible to lower the glass transition temperature (Tg) of the layer composed of the block copolymer formed using the composition of the present invention. Even when annealing is performed at a low temperature for a short time, a good pattern can be formed. The vapor pressure at 20 ° C. of the component (B) is not particularly limited as long as it is 0.05 hPa or less, but is preferably greater than 0 hPa, preferably less than 0.04 hPa, greater than 0 hPa, It is more preferably smaller than 03 hPa, more preferably larger than 0 hPa and even smaller than 0.01 hPa.

  In addition, since the freezing point of the component (B) is 25 ° C. or lower, the component (B) becomes a liquid compound at room temperature of at least about 25 ° C., so that the composition is used on the support by coating or the like. When forming a film, a film having good properties can be formed. Here, the “freezing point” refers to a temperature at which a liquid phase substance maintains an equilibrium state with a solid phase at a standard atmospheric pressure of 1013.25 hPa.

  Moreover, as (B) component, it is preferable that static surface tension is 30 mN / m or more, It is more preferable that it is 30-65 mN / m, It is further more preferable that it is 30-50 mN / m. When the static surface tension is 30 mN / m or more, the film becomes dense when the film is formed using the composition containing the component (B). In particular, in the case of forming a film using the composition of the present invention on a support having a guide pattern, the static surface tension is small, so that the composition can easily enter the fine voids of the guide pattern. It is preferable because a fine pattern faithful to the guide pattern can be obtained. Here, “static surface tension” refers to a static surface tension measured by a dropping method at 20 ° C.

  Specifically, the component (B) is preferably an alcohol such as benzyl glycol, glycerin, phenyl diglycol or benzyl diglycol, or an ester such as triacetin, and particularly preferably phenyl diglycol.

  The weight average molecular weight (Mw) of the component (B) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 600 or less, more preferably 50 to 600, and more preferably 100 to 600. Is more preferable. By making the molecular weight within the above range, it is preferable because good heat fluidity can be obtained even at a low temperature. It can be.

(B) A component may be used individually by 1 type and may be used in combination of 2 or more type. (B) When combining and using multiple types of a component, the combination of alcohol and ester is preferable.
Although content of (B) component in the composition of this invention is not specifically limited, The ratio of (B) component with respect to the sum total of (B) component and (C) component mentioned later is 0.1. It is preferable that it is 40 mass%, 0.3-35 mass% is more preferable, and 0.6-30 mass% is further more preferable.
In addition, the total amount of the (B) component and the (C) component in the composition is not particularly limited, and can be applied at a concentration at which the composition of the present invention can be applied to a support and the like after the desired application. Although it can determine suitably according to a film thickness etc., it is preferable that solid content density | concentration containing (A) component is 0.1-30 mass%, 0.3-25 mass% is more preferable, and 0.3. 6-20 mass% is more preferable.

<(C) component; organic solvent>
The component (C) is not particularly limited as long as it is an organic solvent that does not correspond to the component (B), and any component that can dissolve each component used to form a uniform solution may be used. Conventionally, one or two or more kinds of known solvents for dissolving a polymer compound can be appropriately selected and used.
As the component (C), any component can be used as long as it can dissolve each component to be used to form a uniform solution, and any one of conventionally known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ether alkyl such as ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having a propylene glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME) among these]; cyclic ethers such as dioxane, methyl lactate, Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, List aromatic organic solvents such as phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Can do.

  In addition, as the component (C), it is preferable to select an organic solvent in which the difference in SP value (ΔSP value) from the SP value of the component (B) is in the range of 0 to 5, and the ΔSP value is 0 to 0. More preferably, it is 2.5. Here, the “SP value” is a solubility parameter, and the smaller the difference (ΔSP value) in SP value between the component (B) and the component (C), the better the compatibility and the better the pattern. .

(C) A component may be used independently and may be used as 2 or more types of mixed solvents.
Especially, 1 or more types chosen from the group which consists of 2-heptanone, PGMEA, EL, and (gamma) -butyrolactone are preferable.

  If desired, the composition of the present invention may further contain miscible additives such as additional resins, surfactants for improving coatability, plasticizers, stabilizers, colorants, antihalation agents, dyes, A basic compound or the like can be appropriately added and contained.

[Pattern formation method]
The pattern formation method of the present invention is a method capable of producing a substrate having a nanostructure by utilizing the phase separation structure of the composition of the present invention.
Specifically, after forming a layer containing a block copolymer on a support using the composition of the present invention, phase separation of the layer containing the block copolymer, and among the layers containing the block copolymer, And a step of selectively removing a phase composed of at least one block among a plurality of types of blocks constituting the block copolymer.
Hereinafter, the pattern forming method of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to this.

FIG. 1 shows an embodiment of the pattern forming method of the present invention.
In this embodiment, first, the layer 3 containing a block copolymer is formed on the support 10 by applying the above-described composition of the present invention (step (1)). In the present embodiment, the support 10 is a substrate in which a layer (neutralizing film) 2 made of a base agent is previously formed on the substrate 1, but the present invention is not limited to this. Alternatively, the substrate 1 alone may be used as a support.
Next, the layer 3 containing the block copolymer is phase-separated (step (2)). Finally, in the layer 3 containing the block copolymer, a pattern can be formed by selectively removing the phase 3a composed of at least one of the plural types of blocks constituting the block copolymer. Yes (step (3)).

[Step (1)]
The substrate 1 is not particularly limited as long as it is not dissolved or mixed when a base agent or a block copolymer is applied, and a conventionally known substrate can be used as a substrate for an electronic component.
For example, a silicon substrate, a metal substrate made of metal such as gold, copper, chromium, iron, and aluminum; a metal oxide substrate formed by oxidizing the metal; a glass substrate, a polymer film (polyethylene, polyethylene terephthalate, polyimide, benzocyclobutene) Etc.).
Moreover, the magnitude | size and shape of the board | substrate 1 are not specifically limited. The substrate does not necessarily have a smooth surface, and substrates of various materials and shapes can be selected as appropriate. For example, a substrate having a curved surface, a flat plate having an uneven surface, and a substrate having various shapes such as a flake shape can be used.

As the substrate 1, an inorganic and / or organic film may be provided on the above-described substrate, and an organic film is preferable. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).
The inorganic film can be formed, for example, by coating an inorganic antireflection film composition such as a silicon-based material on a substrate and baking.
The organic film is, for example, a material for forming an organic film in which a resin component or the like constituting the film is dissolved in an organic solvent is applied onto a substrate with a spinner or the like, preferably 200 to 300 ° C., preferably 30 to 300. It can be formed by baking for 2 seconds, more preferably 60 to 180 seconds. The organic film forming material used at this time does not necessarily require sensitivity to light or an electron beam, such as a resist film, and may or may not have such sensitivity. Also good. Specifically, resists and resins generally used in the manufacture of semiconductor elements and liquid crystal display elements can be used.
In addition, the organic film forming material can be etched, particularly dry-etched so that the organic film can be formed by etching the organic film using a block copolymer pattern to transfer the pattern to the organic film. A material capable of forming an organic film is preferable. Among these, a material capable of forming an organic film capable of etching such as oxygen plasma etching is preferable. Such an organic film forming material may be a material conventionally used for forming an organic film such as an organic BARC. Examples include the ARC series manufactured by Brewer Science, the AR series manufactured by Rohm and Haas, and the SWK series manufactured by Tokyo Ohka Kogyo.
Since the base agent of the first aspect of the present invention has a substrate interaction group, even when the substrate 1 provided with the organic film as described above is used, the layer composed of the substrate 1 and the base agent. 2 can be satisfactorily interacted with each other, and the layer 2 made of the base agent can be made a strong and excellent film.

Further, the surface of the substrate 1 may be cleaned in advance. By cleaning the substrate surface, the subsequent neutralization reaction treatment may be performed satisfactorily.
As the cleaning treatment, a conventionally known method can be used, and examples thereof include oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.

A method for applying the base agent on the substrate 1 to form the layer 2 made of the base agent is not particularly limited, and can be formed by a conventionally known method.
For example, the layer 2 made of the base material can be formed by applying the base material onto the substrate 1 by a conventionally known method such as spin coating or using a spinner to form a coating film and drying it. Details of the base agent will be described later.
As a method for drying the coating film, it is sufficient if the organic solvent contained in the base material can be volatilized, and examples thereof include a baking method.
The baking temperature is preferably 80 to 300 ° C, more preferably 100 to 270 ° C, and further preferably 120 to 250 ° C. The baking time is preferably 30 to 500 seconds, and more preferably 60 to 240 seconds.
The surface of the substrate 1 is neutralized by providing the layer 2 made of the base material on the surface of the substrate 1, and only the phase composed of a specific block is in contact with the substrate surface among the layers 3 made of the block copolymer provided on the upper layer. Can be suppressed. As a result, it is possible to form a cylinder structure, a dot structure, a gyroid structure, or the like that is freely oriented with respect to the substrate surface by phase separation of the layer 3 containing the block copolymer.

(Base material)
As a base agent, it has affinity with any of a plurality of types of blocks constituting the layer 3 made of a block copolymer, that is, a plurality of types of blocks in the block copolymer contained in the composition of the present invention described above, and the above effects Although it will not specifically limit if it has, The film | membrane which consists of a resin composition can be used.
The resin composition used as the base agent can be appropriately selected from conventionally known resin compositions used for thin film formation, depending on the type of block constituting the block copolymer. The resin composition used as the base agent may be a thermopolymerizable resin composition or a photosensitive resin composition. Moreover, the composition which can form patterns, such as a positive resist composition and a negative resist composition, may be sufficient.
In addition, the layer 2 made of the base material may be a non-polymerizable film. For example, siloxane-based organic monomolecular films such as phenethyltrichlorosilane, octadecyltrichlorosilane, and hexamethyldisilazane can also be suitably used as the neutralized film.

As such a base agent, for example, a composition containing a resin containing all the constituent units of each block constituting the block copolymer and a constituent unit having high affinity with each block constituting the block copolymer are included. Examples thereof include a composition containing a resin.
For example, when a PS-PMMA block copolymer is used, a resin containing both a structural unit derived from styrene and a structural unit derived from methyl methacrylate as a resin contained in the base agent; PS such as an aromatic ring It is preferable to use a resin or the like that includes both a part having high affinity and a part having high affinity to PMMA such as a functional group having high polarity.

Examples of the resin including both a structural unit derived from styrene and a structural unit derived from methyl methacrylate include a random copolymer obtained by random polymerization of styrene and methyl methacrylate.
As a resin including both a part having high affinity with PS and a part having high affinity with PMMA, for example, as a monomer, it is obtained by polymerizing at least a monomer having an aromatic ring and a monomer having a polar substituent. Resin.
As a monomer having an aromatic ring, one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And monomers having a heteroaryl group in which some of the carbon atoms constituting the ring of these groups are substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom.
In addition, examples of the monomer having a highly polar substituent include hydroxyalkyl in which a part of hydrogen atoms of a trimethoxysilyl group, a trichlorosilyl group, a carboxy group, a hydroxyl group, a cyano group, an amino group, and an alkyl group are substituted with a fluorine atom. And monomers having a group or the like.
In addition, as a compound containing both a site having high affinity with PS and a site having high affinity with PMMA, a compound containing both an aryl group such as phenethyltrichlorosilane and a highly polar substituent, an alkylsilane compound, etc. Examples include compounds containing both an alkyl group and a highly polar substituent.

  In addition, before forming the layer 3 made of the block copolymer, a guide pattern in which a pattern is formed may be provided in advance on the substrate 1 or the substrate 1 provided with the layer 2 made of the base agent. Thereby, it is possible to control the arrangement structure of the phase separation structure according to the shape and surface characteristics of the guide pattern. For example, even in the case of a block copolymer in which a random fingerprint-like phase separation structure is formed in the absence of a guide pattern, by introducing a groove structure of a resist film on the substrate surface, a phase aligned along the groove A separation structure is obtained. A guide pattern may be introduced based on such a principle. In addition, the surface of the guide pattern has affinity with any of the polymers that make up the block copolymer, making it easier to form a phase-separated structure consisting of a lamellar structure or a cylinder structure oriented in the direction perpendicular to the substrate surface. You can also.

  Specifically, for example, a resist composition is applied onto the substrate surface with a spinner or the like, and pre-baking (post-apply baking (PAB)) is performed at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to This is applied for 90 seconds, and this is selectively exposed to ArF excimer laser light through a desired mask pattern using, for example, an ArF exposure apparatus. It is applied for 120 seconds, preferably 60 to 90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a guide pattern faithful to the mask pattern can be formed.

  The height of the guide pattern from the substrate surface (or the neutralized film surface) is preferably equal to or greater than the thickness of the layer 3 containing the block copolymer formed on the substrate surface. The height of the guide pattern from the substrate surface (or neutralized film surface) can be appropriately adjusted depending on, for example, the thickness of the resist film formed by applying a resist composition for forming the guide pattern.

  As a resist composition for forming a guide pattern, a resist composition generally used for forming a resist pattern or a modified product thereof is appropriately selected from those having an affinity for any polymer constituting a block copolymer. Can be used. Examples of the resist composition include a resist composition that generates an acid upon exposure and changes its solubility in a developer due to the action of the acid. The resist composition may be either a positive resist composition that forms a positive pattern in which exposed portions are dissolved and removed, or a negative resist composition that forms a negative pattern in which unexposed portions are dissolved and removed. However, it is preferably a negative resist composition. The negative resist composition includes, for example, an acid generator and a base material component whose solubility in a developer containing an organic solvent is reduced by the action of an acid. A resist composition containing a resin component having a structural unit that decomposes and increases in polarity is preferable.

  In addition, after the block copolymer solution is poured onto the substrate surface on which the guide pattern is formed, heat treatment is performed to cause phase separation. For this reason, as a resist composition which forms a guide pattern, it is preferable that it can form the resist film excellent in solvent resistance and heat resistance. In the present invention, the composition used for forming the layer 3 containing a block copolymer can be subjected to phase separation at a relatively low temperature and in a short time by the action of the component (B). The range of choices expands.

There is no particular limitation on the method for forming the layer 3 containing a block copolymer in which a plurality of types of blocks are bonded on the layer 2 made of the base agent. For example, the composition of the present invention containing a block copolymer Can be formed on the layer 2 made of a base agent. Examples of the coating method include the same as the base agent.
In the present invention, the thickness of the layer 3 containing the block copolymer may be sufficient to cause phase separation, and the lower limit of the thickness is not particularly limited, but the formed phase separation structure In view of the structure period size, the uniformity of the nanostructure, etc., the thickness is preferably 5 nm or more, and more preferably 10 nm or more.

[Process (2)]
The phase separation of the layer 3 containing the block copolymer is performed in such a phase that at least a part of the substrate surface is exposed by heat-treating the support 10 on which the layer 3 containing the block copolymer is formed and selectively removing the block copolymer in a subsequent step. A separation structure is formed. The temperature of the heat treatment is preferably higher than the glass transition temperature of the layer 3 containing the block copolymer to be used and lower than the thermal decomposition temperature. For example, when the block copolymer is PS-PMMA (Mw: 18k-18k), heat treatment is preferably performed at 160 to 270 ° C. for 30 to 3600 seconds. Since the composition for layer 3 containing the block copolymer used in the present invention contains the component (B), the glass transition temperature of the composition is low, and the heat treatment can be performed at a relatively low temperature in a short time.
The heat treatment is preferably performed in a gas having low reactivity such as nitrogen.

[Step (3)]
In the step (3), a pattern is formed by selectively removing the phase 3a composed of at least one block of a plurality of types of blocks constituting the block copolymer from the layer 3 including the block copolymer. To do.
Specifically, the phase of the layers 3 comprising a block copolymer of the substrate after the separation structure was formed, to selectively remove at least some of the blocks of the phase in consisting of block P _B (low molecular weight) . By pre selectively removing portions of the block P _B, results enhanced dissolution in a developer, tends to selectively remove than the phase 3b the phase 3a consisting of block P _B is formed of a block P _A .

Such selective removal process does not affect relative block P _A, if a process capable of decomposing and removing the block P _B, is not particularly limited, the technique used for the removal of the resin film from within, according to the type of block P _a and P _B block can be performed appropriately selected. Also, when the pre-neutralization film is formed on the substrate surface, the neutralization film is also removed as well as phase consisting block P _B. Examples of such removal treatment include oxygen plasma treatment, ozone treatment, UV irradiation treatment, thermal decomposition treatment, and chemical decomposition treatment.

  Although the substrate on which the pattern 3b is formed by phase separation of the layer 3 made of the block copolymer as described above can be used as it is, the shape of the polymer nanostructure on the substrate can be changed by further heat treatment. It can also be changed. The temperature of the heat treatment is preferably higher than the glass transition temperature of the block copolymer used and lower than the thermal decomposition temperature. The heat treatment is preferably performed in a gas having low reactivity such as nitrogen.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

[Examples 1-8, Comparative Examples 1-3]
(Produced by tone of the composition)
Shown in Table 1 (A) were mixed and dissolved component ~ (C) component was manufactured by adjusting the composition for forming a layer containing a block copolymer. However, Example 5 is a reference example.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1: PS-PMMA block copolymer 1 (PS molecular weight: 18000, PMMA molecular weight: 18000, PDI: 1.07).
(A) -2: PS-PMMA block copolymer 2 (PS molecular weight: 45000, PMMA molecular weight: 20000, PDI: 1.07).

(Pattern formation)
The composition of each example shown in Table 1 was spin-coated at 1500 rpm for 60 seconds on an 8-inch silicon wafer to form a coating film having a thickness of 60 nm.
Regarding the coating property when a coating film was formed using the composition of each example, the following criteria were used.
○: A uniform coating film visually.
X: The coating film by which the nonuniformity by white turbidity was confirmed visually.

Thereafter, heat treatment is performed at a temperature and time shown in Table 1 under a nitrogen stream to form a phase separation structure. Using TCA-3822 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), oxygen plasma treatment (200 mL / min, 40 Pa, 40 C., 200 W, 20 seconds) to selectively remove the phase composed of PMMA, and the surface of the obtained substrate was observed with a scanning electron microscope SEMSU8000 (manufactured by Hitachi High-Technologies Corporation).
In the example in which (A) -1 was used as the component (A), the case where a uniform LS pattern of 14 nm was obtained was indicated by ◯, and the case where the LS pattern was not obtained was indicated by ×. Further, in the example using (A) -2 as the component (A), the case where a uniform hole pattern of 20 nm was obtained was marked with ◯, and the case where it was not obtained was marked with x. The results are shown in Table 1.

In Example 3, after a guide pattern was formed in advance, a pattern was formed using the composition shown in Table 1 in the same manner as described above.
Specifically, a resist composition to be described later is applied using a spinner on a substrate having an antireflection film (ARC-29A manufactured by Brewer Science Co., Ltd.) having a thickness of 85 nm formed on the substrate, and 85 ° C. on a hot plate. A pre-baking (PAB) process was performed under the conditions for 60 seconds, followed by drying to form a resist film having a thickness of 100 nm.
Next, an ArF excimer laser was selectively irradiated through a mask by an ArF immersion exposure apparatus NSR-S308F (manufactured by Nikon; NA (numerical aperture) = 0.92, σ0.95). Then, PEB treatment at 125 ° C. for 60 seconds was performed, and further development treatment was carried out with butyl acetate at 23 ° C. for 16 seconds, followed by shake-off drying.
As a result, in each example, a contact hole (CH) pattern having a hole diameter of 85 nm and a pitch of 149 nm was formed in the resist film.
Using the substrate having the CH holes formed thereon, a layer containing a block copolymer was formed using the composition of Example 3, and the heat treatment for phase separation was performed at 200 ° C. for 300 seconds in the same manner as above. As a result of phase separation and pattern formation, a 20 nm hole was formed in the hole of the guide pattern having a hole diameter of 85 nm.

The composition of the resist composition used for forming the guide pattern is as follows.
-The following high molecular compound (A) -1 [Mw = 10000, Mw / Mn = 1.78, 1 / m / n / o = 20/40/20/20 (molar ratio)]: 100 mass parts.
-The following compound (B) -1: 10 mass parts.
-Tri-n-pentylamine: 1 part by mass.
Salicylic acid: 1.5 parts by mass
-PGMEA: 2500 mass parts.

  Further, in Example 7, after a guide pattern was formed in the same manner as in Example 3, a pattern was formed using the composition shown in Table 1 in the same manner as above. As a result, a 20 nm hole was formed in the guide pattern hole having a hole diameter of 85 nm.

From the above results, in Examples 1 to 8 where the composition of the present invention was used to form a phase composed of a block copolymer, a good phase separation pattern was obtained at a relatively low temperature of 150 to 200 ° C., whereas Comparative Example 1 In ~ 3, a pattern could not be obtained even at 200 to 220 ° C.
Moreover, from the results of Examples 3 and 7 using the guide resist, it was confirmed that when the composition of the present invention was used, a desired pattern was obtained by using the guide pattern together.

1 ... substrate, 2 ... layer made of a base material, 10 ... support, 3 ... layer containing a block copolymer, a phase consisting 3a ... _{P B} block, phase consisting 3b ... _{P A} block

Claims (3)

A block copolymer in which multiple types of blocks are combined;
One or more alcohols selected from the group consisting of benzyl glycol, glycerin, phenyl diglycol and benzyl diglycol ;
A composition containing one or more organic solvents selected from the group consisting of 2-heptanone, propylene glycol monomethyl ether acetate, ethyl lactate, and γ-butyrolactone . Forming a layer containing a block copolymer on a support using the composition according to claim 1, and then phase-separating the layer containing the block copolymer;
And a step of selectively removing a phase composed of at least one block among a plurality of types of blocks constituting the block copolymer from the layer containing the block copolymer. The support has a guide pattern,
The pattern formation method according to claim 2 , wherein the guide pattern is formed using a resist composition that generates an acid upon exposure and changes its solubility in a developer due to the action of the acid.

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