JP2011080087A - Method for promoting self-organization of block copolymer, and method for forming self-organization pattern of block copolymer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the throughput of pattern forming by the self-organization of a block copolymer. <P>SOLUTION: A block copolymer film 203 is formed on a substrate 201, and then the film 203 is annealed, for example, under a humidification of about 40%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for promoting self-organization of a block copolymer used for pattern formation such as a manufacturing process of a semiconductor device and a method for forming a self-organized pattern of a block copolymer using the same.

  Along with the large integration of semiconductor integrated circuits and downsizing of semiconductor elements, acceleration of development of lithography technology is desired. At present, as exposure light, pattern formation is performed by photolithography using a mercury lamp, a KrF excimer laser, an ArF excimer laser, or the like.

  Recently, immersion lithography has been proposed in order to further refine the pattern using a conventional exposure wavelength. In addition, the use of extreme ultraviolet light as exposure light with a shorter wavelength is also being studied.

  Further, as a candidate aiming for a finer pattern forming method, a method of forming a pattern from the bottom up rather than from the bottom down has been proposed (see, for example, Patent Document 1). Specifically, an ultrafine pattern by self-organization using a block copolymer obtained by copolymerizing a polymer chain having one property with a monomer unit and another polymer chain (monomer unit) having different properties. It is a forming method. According to this method, by annealing the block copolymer film, the monomer units having different properties repel each other and the monomer units having the same properties are patterned in a self-aligned manner (directed self-assembly). ).

  Hereinafter, a conventional pattern forming method using a block copolymer will be described with reference to the drawings.

  First, as shown in FIG. 7A, a block copolymer film 2 having the following composition and a film thickness of 0.07 μm is formed on a substrate 1.

Poly (styrene (50mol%)-methylmethacrylate (50mol%)) (block copolymer) ... ... 2g
Propylene glycol monomethyl ether acetate (solvent) 10g
Next, as shown in FIG. 7B, the formed block copolymer film 2 is annealed in an oven at a temperature of 180 ° C. for 24 hours, and the line width shown in FIG. 7C is 16 nm. Thus, the first pattern 2a and the second pattern 2b having a self-assembled lamellar structure (layer structure) are obtained. In FIG. 7, the block copolymer film 2 is formed inside the guide pattern, but the guide pattern is omitted here.

JP 2008-149447 A

  However, in the pattern formation method using the conventional block copolymer, annealing for self-organization of the block copolymer film requires a long time of about 24 hours, which becomes a barrier to mass production technology in the semiconductor manufacturing process. There is a problem that it is difficult to apply industrially.

  In view of the above-described conventional problems, an object of the present invention is to improve the throughput of pattern formation by self-assembly of a block copolymer.

  As a result of various studies on the self-assembly of the block copolymer, the present inventors have conducted the following method during annealing of one of the monomer units constituting the block copolymer, for example, a hydrophilic or hydrophobic monomer unit. Has gained the knowledge that it is easier to self-assemble.

  First, when the block copolymer film is annealed in an inert gas atmosphere, the outside (mainly upward) of the block copolymer film becomes non-polar, so that, for example, a monomer unit having hydrophobicity (hydrophobic unit) is formed in the film. Because it is strongly attracted to the outside, self-organization is promoted.

  Further, when the block copolymer film is annealed under humidification, the outside of the block copolymer film (mainly upward) becomes hydrophilic. For example, a hydrophilic monomer unit (hydrophilic unit) is outside the film. It is strongly attracted to so that self-organization is promoted. Here, as a method of applying humidification, a method of introducing water vapor into the oven can be mentioned.

  In addition, when a water-soluble polymer film is formed on the block copolymer film, a water-soluble polymer is formed on the upper surface of the block copolymer film. For example, hydrophilic monomer units are strongly attracted to the outside (upper) of the film. So self-organization is promoted. An exposure method in which a water-soluble polymer film is formed on a resist film and exposed is conventionally known, but the present invention is different from the conventional method in that a pattern can be formed without exposure. In addition, the water-soluble polymer film is removed by water or the like after annealing, but when cured by annealing, it can be removed by ashing of oxygen-based plasma.

  Annealing of the block copolymer film according to the present invention can be performed, for example, in an oven at a temperature of about 150 ° C. or higher. According to the present invention, the annealing time can be greatly shortened, for example, about 2 to 6 hours. However, the present invention is not limited to this range.

  The present invention has been made based on the above findings, and when annealing the block copolymer film, the atmosphere mainly contacting the upper surface of the annealed block copolymer film is made hydrophilic or hydrophobic, or is in contact with the upper surface. The other film is made hydrophilic or hydrophobic, and is specifically realized by the following method.

  A method for promoting self-assembly of a first block copolymer according to the present invention includes a step of forming a first film made of a block copolymer on a substrate, and a step of annealing the first film in an inert gas atmosphere. It is characterized by having.

  According to the method for promoting self-assembly of the first block copolymer, since the first film made of the block copolymer is annealed in an inert gas atmosphere, the outside (mainly above) of the first film is in a state of no polarity. Therefore, for example, the monomer unit having hydrophobicity is strongly attracted to the outside of the first film, so that self-assembly is promoted. Therefore, the throughput of pattern formation by the self-assembly of the block copolymer is improved.

  In the first block copolymer self-assembly promotion method, helium, neon, argon, krypton, or xenon can be used as the inert gas.

  The second block copolymer self-assembly promotion method according to the present invention includes a step of forming a first film made of a block copolymer on a substrate, and a step of annealing the first film under humidification. It is characterized by.

  According to the method for promoting the self-assembly of the second block copolymer, since the first film made of the block copolymer is annealed under humidification, the outside (mainly above) of the first film becomes hydrophilic. For example, since the hydrophilic monomer unit is strongly attracted to the outside of the first film, self-organization is promoted. Therefore, the throughput of pattern formation by the self-assembly of the block copolymer is improved.

  In the second method for promoting the self-assembly of the block copolymer, the annealing under humidification is preferably performed in a humidified atmosphere having a humidity of 30% or more.

  The third method for promoting self-assembly of a block copolymer according to the present invention includes a step of forming a first film made of a block copolymer on a substrate, and a second process made of a water-soluble polymer on the first film. And a step of annealing the first film and the second film.

  According to the method for promoting self-assembly of the third block copolymer, since the second film made of the water-soluble polymer is formed on the first film made of the block copolymer, the upper surface of the first film is water-soluble. A polymer is formed. For this reason, for example, the monomer unit having hydrophilicity is strongly attracted above the first film, so that self-organization is promoted. Therefore, the throughput of pattern formation by the self-assembly of the block copolymer is improved.

  In the third block copolymer self-assembly promotion method, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, or polystyrene sulfonic acid can be used as the water-soluble polymer. The film thickness of the second film made of the water-soluble polymer is preferably about 50 nm or less.

  In the first to third block copolymer self-assembly promotion methods, the block copolymer is preferably composed of a hydrophilic unit and a hydrophobic unit.

  In this case, methacrylate, butadiene, vinyl acetate, acrylate, acrylamide, acrylonitrile, acrylic acid, vinyl alcohol, ethylene glycol or propylene glycol can be used for the hydrophilic unit.

  In this case, styrene, xylene, or ethylene can be used for the hydrophobic unit.

  If the copolymerization ratio of the block copolymer containing two types of monomer units is about 50 to 50, the self-assembled pattern has a lamellar structure. As the ratio of any one of the monomer units decreases from this ratio, a cylinder structure and further a dot structure are obtained.

  A first block copolymer self-assembly pattern forming method according to the present invention includes a step of forming a guide pattern having hydrophilicity or hydrophobicity and an opening on a substrate, and a guide pattern on the substrate. A step of forming a first film made of a block copolymer in the opening of the substrate, a step of self-organizing the first film by annealing the first film in an inert gas atmosphere, Forming a self-assembled pattern from the first film.

  According to the first block copolymer self-assembly pattern forming method, the first film made of the block copolymer is formed in the opening of the guide pattern having hydrophilicity or hydrophobicity and having the opening, and then Since the first film is annealed in the inert gas atmosphere, the self-organization of the first film is promoted as described above. For this reason, it is possible to improve the throughput of the self-assembled pattern made of the block copolymer.

  In the first block copolymer self-assembly pattern forming method, helium, neon, argon, krypton, or xenon can be used as the inert gas.

  The second block copolymer self-organized pattern forming method according to the present invention includes a step of forming a hydrophilic or hydrophobic guide pattern having an opening on a substrate, and a guide pattern on the substrate. Forming a first film made of a block copolymer in the opening of the first film; annealing the first film under humidification to self-assemble the first film; and And a step of forming a self-assembled pattern from one film.

  According to the second block copolymer self-assembly pattern forming method, the first film made of the block copolymer is formed in the opening of the guide pattern having hydrophilicity or hydrophobicity and having the opening, Since the first film is annealed under humidification, self-organization of the first film is promoted as described above. For this reason, it is possible to improve the throughput of the self-assembled pattern made of the block copolymer.

  In the second block copolymer self-assembly pattern forming method, it is preferable that the annealing under humidification is performed in a humidified atmosphere having a humidity of 30% or more.

  The third method for forming a self-organized pattern of a block copolymer according to the present invention includes a step of forming a hydrophilic or hydrophobic guide pattern having an opening on a substrate, and a guide pattern on the substrate. Forming a first film made of a block copolymer in the opening, a step of forming a second film made of a water-soluble polymer on the first film, a first film and a second film A step of self-organizing the first film by annealing the film; and a step of forming a self-assembled pattern from the first film that has been self-assembled after removing the second film. It is characterized by.

  According to the third block copolymer self-assembly pattern forming method, the first film made of the block copolymer is formed in the opening of the guide pattern having hydrophilicity or hydrophobicity and having the opening, Since annealing is performed with the second film made of the water-soluble polymer formed on the first film, the second film made of the water-soluble polymer promotes self-organization of the first film as described above. Is done. For this reason, it is possible to improve the throughput of the self-assembled pattern made of the block copolymer.

  In the third method for forming a self-assembled pattern of the block copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, or polystyrene sulfonic acid can be used as the water-soluble polymer.

  In the first to third block copolymer self-assembly pattern forming methods, the block copolymer is preferably composed of a hydrophilic unit and a hydrophobic unit.

  In this case, methacrylate, butadiene, vinyl acetate, acrylate, acrylamide, acrylonitrile, acrylic acid, vinyl alcohol, ethylene glycol or propylene glycol can be used for the hydrophilic unit.

  In this case, styrene, xylene, or ethylene can be used for the hydrophobic unit.

  In this case, in the step of forming the self-assembled pattern, the self-assembled pattern may be formed by etching the first pattern including the hydrophilic unit or the second pattern including the hydrophobic unit. it can.

  According to the block copolymer self-assembly promotion method and the block copolymer self-assembly pattern formation method using the same according to the present invention, the throughput in pattern formation by block copolymer self-assembly can be improved.

(A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows 1 process of the pattern formation method which concerns on the 1st Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows 1 process of the pattern formation method which concerns on the 2nd Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 3rd Embodiment of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method which concerns on the 3rd Embodiment of this invention. (A)-(c) is sectional drawing which shows each process of the pattern formation method using the conventional block copolymer.

(First embodiment)
A pattern forming method using the block copolymer according to the first embodiment of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 1A, a solution obtained by dissolving hydrophilic hydrogenated silsesquioxane in methyl isobutyl ketone is spin-coated on a substrate 101, and subsequently the temperature is set to 110 by a hot plate. A hydrogenated silsesquioxane film having a thickness of 40 nm is formed by baking at 60 ° C. for 60 seconds. Thereafter, the formed hydrogenated silsesquioxane film is selectively irradiated with an electron beam exposure having a voltage of 100 kV, and subsequently developed with an aqueous tetramethylammonium hydroxide solution having a concentration of 2.3 wt%. Thus, a guide pattern 102 having an opening 102a having a width of 30 nm is formed from the hydrogenated silsesquioxane film.

Next, as shown in FIG. 1B, a block copolymer film 103 having the following composition and a thickness of 30 nm is formed in the opening 102a of the guide pattern 102. Poly (styrene (60 mol%)-methyl methacrylate (40mol%)) (Block copolymer) ... 2g
Propylene glycol monomethyl ether acetate (solvent) 10g
Next, as shown in FIG. 1C, the block copolymer film 103 is annealed in an oven for about 3 hours at a temperature of 180 ° C. in an atmosphere of neon (Ne) as an inert gas. As a result, as shown in FIG. 1D, a first pattern 103a and a second pattern 103b having a lamellar structure with a line width of 16 nm and self-organized perpendicularly to the substrate 101 are obtained. Here, since the guide pattern 102 is made of hydrogenated silsesquioxane having hydrophilicity, the first pattern 103a in contact with the side surface of the guide pattern 102 is mainly composed of polymethylmethacrylate having hydrophilicity, The second pattern 103b inside the pattern 103a is mainly composed of polystyrene having hydrophobicity.

  Next, since there is a large difference in the etching rate between polystyrene and polymethyl methacrylate with respect to the oxygen-based gas, that is, the etching rate of polymethyl methacrylate is larger than that of polystyrene, the first pattern 103a is formed with oxygen-based gas. As shown in FIG. 2, the second pattern 103b made of polystyrene can be formed by annealing for about 3 hours. Therefore, pattern formation using a block copolymer can be applied to a semiconductor device manufacturing process.

  In this embodiment, neon (Ne) is used as the inert gas, but instead of neon, helium (He), argon (Ar), krypton (Kr), xenon (Xe), or any of these Two or more gas mixtures can be used.

(Second Embodiment)
Hereinafter, a pattern forming method using the block copolymer according to the second embodiment of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 3A, a solution in which hydrogenated silsesquioxane having hydrophilicity is dissolved in methyl isobutyl ketone is spin-coated on a substrate 201, and subsequently, the temperature is set to 110 by a hot plate. A hydrogenated silsesquioxane film having a thickness of 40 nm is formed by baking at 60 ° C. for 60 seconds. Thereafter, the formed hydrogenated silsesquioxane film is selectively irradiated with an electron beam exposure having a voltage of 100 kV, and subsequently developed with an aqueous tetramethylammonium hydroxide solution having a concentration of 2.3 wt%. Thus, a guide pattern 202 having an opening 202a having a width of 30 nm is formed from the hydrogenated silsesquioxane film.

Next, as shown in FIG. 3B, a block copolymer film 203 having the following composition and a thickness of 30 nm is formed in the opening 202a of the guide pattern 202. Poly (styrene (40 mol%)-methyl methacrylate (60mol%)) (Block copolymer) ... 2g
Propylene glycol monomethyl ether acetate (solvent) 10g
Next, as shown in FIG. 3C, water vapor is introduced around the block copolymer film 203, the humidity is about 40% relative to the block copolymer film 203, the temperature is set to 190 ° C. and about 2%. Annealing with oven for hours. As a result, as shown in FIG. 3D, a first pattern 203a and a second pattern 203b having a lamellar structure with a line width of 16 nm and self-organized perpendicularly to the substrate 201 are obtained. Here, since the guide pattern 202 is made of hydrogenated silsesquioxane having hydrophilicity, the first pattern 203a in contact with the side surface of the guide pattern 202 is mainly composed of polymethylmethacrylate having hydrophilicity, The second pattern 203b inside the pattern 203a is mainly composed of polystyrene having hydrophobicity.

  Next, when the first pattern 203a and the second pattern 203b are etched with an oxygen-based gas, as shown in FIG. 4, the first pattern 203a having a large etching rate is etched, and polystyrene is used. The second pattern 203b can be formed by annealing for about 2 hours. Therefore, pattern formation using a block copolymer can be applied to a semiconductor device manufacturing process.

  In the present embodiment, the humidity during annealing is set to about 40%, but the humidity may be 30% or more.

(Third embodiment)
Hereinafter, a pattern forming method using the block copolymer according to the third embodiment of the present invention will be described with reference to FIGS. 5 (a) to 5 (d), FIG. 6 (a), and FIG. 6 (b). .

  First, as shown in FIG. 5 (a), a solution obtained by dissolving hydrophilic hydrogenated silsesquioxane in methyl isobutyl ketone is spin-coated on a substrate 301, and subsequently the temperature is set to 110 by a hot plate. A hydrogenated silsesquioxane film having a thickness of 40 nm is formed by baking at 60 ° C. for 60 seconds. Thereafter, the formed hydrogenated silsesquioxane film is selectively irradiated with an electron beam exposure having a voltage of 100 kV, and subsequently developed with an aqueous tetramethylammonium hydroxide solution having a concentration of 2.3 wt%. Thus, a guide pattern 302 having an opening 302a having a width of 30 nm is formed from the hydrogenated silsesquioxane film.

Next, as shown in FIG. 5B, a block copolymer film 303 having the following composition and a thickness of 30 nm is formed in the opening 302a of the guide pattern 302. Poly (styrene (50 mol%)-methyl methacrylate (50mol%)) (Block copolymer) ... 2g
Propylene glycol monomethyl ether acetate (solvent) 10g
Next, as shown in FIG. 5C, a water-soluble polymer film 304 made of polyvinyl alcohol having a thickness of 20 nm is formed on the block copolymer film 303.

  Next, as shown in FIG. 5D, the water-soluble polymer film 304 and the block copolymer film 303 are annealed in an oven at a temperature of 180 ° C. for about 3 hours.

  Next, the water-soluble polymer film 304 is removed with water or the like, or ashed with an oxygen-based gas, and self-organized perpendicularly to the substrate 301 as shown in FIG. A first pattern 303a and a second pattern 303b having a structure are obtained. Here, since the guide pattern 302 is made of hydrogenated silsesquioxane having hydrophilicity, the first pattern 303a in contact with the side surface of the guide pattern 302 is mainly composed of polymethylmethacrylate having hydrophilicity, The second pattern 303b inside the pattern 303a has hydrophobic polystyrene as a main component.

  Next, when the first pattern 303a and the second pattern 303b are etched with an oxygen-based gas, as shown in FIG. 6B, the first pattern 303a having a high etching rate is etched. The second pattern 303b made of polystyrene can be formed by annealing for about 3 hours. Therefore, pattern formation using a block copolymer can be applied to a semiconductor device manufacturing process.

  In the present embodiment, polyvinyl alcohol is used for the water-soluble polymer film 304, but polyvinyl pyrrolidone, polyacrylic acid, or polystyrene sulfonic acid can be used instead.

  In this embodiment, the water-soluble polymer film 304 is also formed on the guide pattern 302. However, depending on the film thicknesses of the guide pattern 302, the block copolymer film 303, and the water-soluble polymer film 304, the guide pattern 302 It may be formed only on the block copolymer film 303 without covering the top of 302.

  In each of the first to third embodiments, methacrylate is used as the hydrophilic unit constituting the block copolymer film and styrene is used as the hydrophobic unit. However, the present invention is not limited to this. For example, butadiene, vinyl acetate, acrylate, acrylamide, acrylonitrile, acrylic acid, vinyl alcohol, ethylene glycol or propylene glycol can be used for the hydrophilic unit instead of methacrylate, and styrene is used for the hydrophobic unit. Instead of xylene or ethylene can be used. Furthermore, as long as the properties of the monomer unit can be maintained, the monomer constituting the monomer unit does not have to be a single monomer, and a polymer chain obtained by mixing a plurality of monomers may be used as the monomer unit.

  Moreover, although the silsesquioxane hydride was used as a material which comprises a guide pattern, it can replace with this and can use tetraalkoxysilane etc.

  In the first to third embodiments, a lamellar structure in a direction perpendicular to the substrate is formed by a hydrophilic guide pattern. Therefore, the inert gas atmosphere at the time of annealing in the first embodiment, the humidified atmosphere at the time of annealing in the second embodiment, and the use of the water-soluble polymer film in the third embodiment has a lamella structure perpendicular to the substrate. It is limited to the extent to promote and does not impair the lamellar structure.

  The block copolymer self-assembly promotion method and the block copolymer self-assembly pattern formation method using the block copolymer self-assembly pattern formation method according to the present invention can improve the throughput in pattern formation by block copolymer self-assembly, and manufacture a semiconductor device. This is useful for forming a fine pattern in a process.

101 substrate 102 guide pattern 102a opening 103 block copolymer film 103a first pattern 103b second pattern 201 substrate 202 guide pattern 202a opening 203 block copolymer film 203a first pattern 203b second pattern 301 substrate 302 guide pattern 302a Opening 303 Block copolymer film 303a First pattern 303b Second pattern 304 Water-soluble polymer film

Claims (11)

Forming a first film of a block copolymer on a substrate;
And a step of annealing the first film under humidification. A method for promoting the self-assembly of a block copolymer.   The method of promoting self-assembly of a block copolymer according to claim 1, wherein the annealing under humidification is performed in a humidified atmosphere having a humidity of 30% or more.   The method for promoting self-assembly of a block copolymer according to claim 1 or 2, wherein the block copolymer comprises a hydrophilic unit and a hydrophobic unit.   The self-assembly promotion of a block copolymer according to claim 3, wherein the hydrophilic unit is methacrylate, butadiene, vinyl acetate, acrylate, acrylamide, acrylonitrile, acrylic acid, vinyl alcohol, ethylene glycol or propylene glycol. Method.   The method for promoting self-assembly of a block copolymer according to claim 3 or 4, wherein the hydrophobic unit is styrene, xylene, or ethylene. Forming a guide pattern having hydrophilicity or hydrophobicity and having an opening on a substrate;
Forming a first film of a block copolymer in the opening of the guide pattern on the substrate;
Self-organizing the first film by annealing the first film under humidification;
Forming a self-assembled pattern from the self-assembled first film. A method for forming a self-assembled pattern of a block copolymer.   The method for forming a self-assembled pattern of a block copolymer according to claim 6, wherein the annealing under humidification is performed in a humidified atmosphere having a humidity of 30% or more.   The method for forming a self-assembled pattern of a block copolymer according to claim 6 or 7, wherein the block copolymer comprises a hydrophilic unit and a hydrophobic unit.   The block copolymer self-assembly pattern according to claim 8, wherein the hydrophilic unit is methacrylate, butadiene, vinyl acetate, acrylate, acrylamide, acrylonitrile, acrylic acid, vinyl alcohol, ethylene glycol or propylene glycol. Forming method.   The method for forming a self-assembled pattern of a block copolymer according to claim 8 or 9, wherein the hydrophobic unit is styrene, xylene, or ethylene.   In the step of forming the self-assembled pattern, the self-assembled pattern is formed by etching the first pattern including the hydrophilic unit or the second pattern including the hydrophobic unit. The method for forming a self-assembled pattern of a block copolymer according to any one of claims 8 to 10.

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