JP2015205405A - Substrate with fine irregular structure and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate with a fine irregular structure which provides a high degree of freedom of selecting structures and materials constituting a precursor of an inorganic oxide, a block copolymer and a graft copolymer and allows formation of a fine irregular structure at low costs with high accuracy.SOLUTION: A production method of a substrate with a fine irregular structure includes: a step of forming a resin composition layer containing a block copolymer or a graft copolymer on a substrate (1); a step of removing, with a chemical, one phase of the resin composition layer phase-separated by self-organization of the resin composition layer to form a self-organized pattern (2b) composed of the other phase; a step of filling space parts (5) of the self-organized pattern (2b) with a precursor solution (6) of an inorganic oxide (7); and a step of transforming the precursor solution (6) to the inorganic oxide (7) by heating and removing the self-organized pattern so as to form a fine irregular structure (10) composed of the inorganic oxide (7) on the substrate (1).

Description

  The present invention relates to a substrate with a fine concavo-convex structure provided on a substrate with a fine concavo-convex structure formed using a self-organized pattern of a block copolymer or the like, and a method for producing the same.

  The structure with a fine concavo-convex structure on the substrate is expected to be applied to the surface shape of optical elements, intermediates in the optical element manufacturing process, and molds for transferring fine concavo-convex structures to the element surface. Has been. Conventionally, electron beam lithography, nanoimprinting, and the like have been studied as processing methods at the research level for forming fine concavo-convex structures.

  However, these methods have a high apparatus cost and must be manufactured by controlling the pitch and arrangement of the fine concavo-convex structure in the nano size, so that it is difficult to manufacture and practical application is difficult.

Japanese Patent No. 3940546

Nano.Lett., Vol. 5, No. 10, 2005 (2014-2018).

  In Patent Document 1, a fine concavo-convex structure is produced by using self-organized lithography of a block copolymer.

  However, in Patent Document 1, a self-organized pattern of a block copolymer is formed on the surface of an inorganic oxide layer, and a fine concavo-convex structure is transferred to the inorganic oxide layer by dry etching using the self-organized pattern as a mask. In addition, there is a problem that an expensive dry etching apparatus is required for pattern transfer.

  In Non-Patent Document 1, an inorganic oxide precursor is selectively dissolved in one phase constituting the block copolymer and heated to form the inorganic oxide and to thermally decompose the block copolymer. Have been removed.

  However, in the method of Non-Patent Document 1, the inorganic oxide precursor and the block copolymer have a structure and material in order to selectively dissolve the precursor of the inorganic oxide in one phase formed by the block copolymer. There was a problem of being limited.

  The present invention has been made in view of the above points, and in particular, the structure and materials constituting the precursor of the inorganic oxide, the block copolymer, and the graft copolymer are highly flexible, and the fine concavo-convex structure can be produced at low cost. It is another object of the present invention to provide a substrate with a fine concavo-convex structure that can be formed with high accuracy and a method for producing the same.

  In the present invention, a fine concavo-convex structure made of an inorganic oxide is formed on a substrate using a self-organized pattern by a block copolymer or a graft copolymer. In the method for producing a substrate with a fine concavo-convex structure, the present inventors can form a fine concavo-convex structure with a lower cost and more accurately than the prior art, and further constitute inorganic oxide precursors, block copolymers and graft copolymers. It came to the invention which can raise the freedom degree of selection of a structure or material. That is, the present invention is as follows.

  The method for producing a substrate with a fine concavo-convex structure in the present invention includes a step of forming a resin composition layer containing a block copolymer or a graft copolymer on a substrate, a step of self-organizing the resin composition layer, Formed by removing one phase of the resin composition layer phase-separated by the self-assembly with a chemical solution to form a self-assembled pattern composed of the other phase, and removing the one phase. The step of filling the space of the self-organization pattern with an inorganic oxide precursor and the transformation of the inorganic oxide precursor to the inorganic oxide by heating and the removal of the self-organization pattern And forming a fine concavo-convex structure made of the inorganic oxide on the base material.

  In the present invention, the heating temperature is preferably 200 ° C. or higher. The heating temperature is more preferably 300 ° C. or higher.

  In the present invention, it is preferable to expose the resin composition layer to UV light before removing the one phase with a chemical solution.

  Moreover, in this invention, it is preferable that the pitch of the said fine uneven structure is 20-1000 nm, and the height of the said fine uneven structure is 20-1000 nm. Moreover, in this invention, it is preferable that the pitch of the said fine uneven structure is 100-1000 nm, and the height of the said fine uneven structure is 100-1000 nm.

  Moreover, the base material with a fine concavo-convex structure in the present invention includes a base material and a fine concavo-convex structure formed on the base material, and the fine concavo-convex structure is formed by any one of the manufacturing methods described above. It is characterized by that.

  According to the present invention, a fine concavo-convex structure can be obtained accurately without using high-cost dry etching requiring a vacuum process, and without limiting the structure and material of the precursor, block copolymer, and graft copolymer of the inorganic oxide. An attached substrate can be formed.

It is process drawing for demonstrating the manufacturing method of the base material with a fine uneven structure in this invention. It is process drawing performed after FIG.

  Hereinafter, an embodiment of the present invention (hereinafter abbreviated as “this embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  The substrate with a fine concavo-convex structure in the present invention has a base material and a fine concavo-convex structure formed on the substrate, and has a structure in which the fine concavo-convex structure is formed of an inorganic oxide.

  Here, the “base material” means a support capable of forming a fine concavo-convex structure on the surface, but the structure, shape, material and the like of the base material are not particularly limited. A base material does not ask | require distinction, such as a film form, a sheet form, plate shape, and a molded article. The substrate may be transparent or opaque. However, when the substrate is a substrate for a light emitting element such as an LED, the substrate is made of a light-transmitting material. The light emitting element base material refers to a laminate in which a semiconductor layer, an active layer (light emitting layer), and the like are laminated on a substrate. Therefore, in the case of the light emitting element substrate, a fine uneven structure is formed on the surface of the laminate. The substrate with a fine concavo-convex structure in the present invention may be a mold or the like.

  Further, the fine concavo-convex structure made of the inorganic oxide in the present invention may be an intermediate structure other than the structure which is the final structure left in the final molded body. That is, when the final molded body is formed, a fine concavo-convex structure made of the inorganic oxide of the present invention exists as an intermediate, and the fine concavo-convex structure of the present invention may not be left in the final molded body.

  Hereafter, the manufacturing method of the base material with a fine uneven structure in this invention is demonstrated using FIG.1 and FIG.2.

  In the step shown in FIG. 1A, first, a substrate 1 is prepared. The substrate 1 may be organic or inorganic. The substrate 1 may have a single layer structure or a laminated structure. The structure and material of the substrate 1 can be freely selected depending on the intended use. If the substrate 1 is a substrate for a light emitting element such as an LED, for example, the substrate 1 is a laminate in which an n-type semiconductor layer, an active layer (light emitting layer), a p-type semiconductor layer, and the like are laminated on a substrate. It is. If the substrate 1 is a mold, the substrate 1 constitutes a molded product formed of resin, ceramics, or the like.

  Subsequently, a resin composition layer 2 containing a block copolymer or a graft copolymer is formed on the surface (upper surface) 1a of the substrate 1. The resin composition layer 2 will be described in detail.

  A block copolymer is a polymer having a structure in which two homopolymers are chemically bonded at one place. The graft copolymer is a polymer having a structure in which a polymer made of another kind of monomer is branched and bonded to a polymer chain.

  When these polymers are made into a thin film and heated, microphase separation occurs and the same polymers aggregate to form a nano-level sea-island structure. This is self-organization. The two polymers constituting the block copolymer or graft copolymer have different etching resistances. Therefore, it is possible to selectively remove the polymer on the side aggregated in an island shape or the polymer on the side aggregated in a sea shape. Thereby, a self-assembled pattern by a block copolymer or a graft copolymer can be formed.

  The block copolymer or graft copolymer in the present invention preferably has a structure containing an aromatic ring-containing polymer and poly (meth) acrylate as a block part or a graft part.

  As the resin composition, the block part of the block copolymer or the graft part of the graft copolymer may further include an aromatic ring-containing homopolymer composed of a monomer constituting an aromatic ring-containing polymer or a poly (meth) acrylate composed of a monomer constituting a poly (meth) acrylate. It preferably contains a (meth) acrylate homopolymer. A block copolymer or a graft copolymer alone can usually form only a fine concavo-convex structure with a pitch of 100 nm or less, but an aromatic ring-containing homopolymer or poly (meth) acrylate homopolymer is added to the block portion of the block copolymer or the graft portion of the graft copolymer. By containing, a fine concavo-convex structure with a pitch exceeding 100 nm can be formed.

  The aromatic ring-containing polymer contained as a block part of a block copolymer or a graft part of a graft copolymer is a homopolymer of a vinyl monomer having a heteroaromatic ring such as an aromatic ring or a pyridine ring as a side chain. PS), polymethylstyrene, polyethylstyrene, polyt-butylstyrene, polymethoxystyrene, polyN, N-dimethylaminostyrene, polychlorostyrene, polybromostyrene, polytrifluoromethylstyrene, polytrimethylsilylstyrene, Polydivinylbenzene, polycyanostyrene, poly α-methylstyrene, polyvinyl naphthalene, polyvinyl biphenyl, polyvinyl pyrene, polyvinyl phenanthrene, polyisopropenyl naphthalene, polyvinyl pyridine It can be mentioned. The aromatic ring-containing polymer most preferably used here is polystyrene from the viewpoint of availability of raw material monomers and ease of synthesis.

  The poly (meth) acrylate which is another component contained as a block part of the block copolymer or a graft part of the graft copolymer used in the present invention is at least one kind selected from the group consisting of the following acrylate monomers and methacrylate monomers. It is a polymer or a copolymer. Examples of the group consisting of acrylate monomers and methacrylate monomers that can be used here include methyl methacrylate (hereinafter also referred to as MMA), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid. Isobutyl acid, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid t -Butyl, n-hexyl acrylate, cyclohexyl acrylate and the like. The poly (meth) acrylate most preferably used here is a methyl methacrylate homopolymer polymethyl methacrylate (hereinafter also referred to as PMMA) from the viewpoint of availability of raw material monomers and ease of synthesis.

  The number average molecular weight of the block copolymer or graft copolymer used in the present invention is preferably 30,000 or more, more preferably 50,000 or more, from the viewpoint of phase separation. On the other hand, from the viewpoint of molecular weight controllability at the time of synthesis and viscosity suppression when used as a composition, 5 million or less is preferable, and 3 million or less is more preferable. As for the composition of the block copolymer or graft copolymer, the ratio of the aromatic ring-containing polymer to the poly (meth) acrylate can be arbitrarily changed in the range of 1: 9 to 9: 1. In addition, other blocks or graft units such as polyethylene oxide may be contained within a range not exceeding 50% by mass.

  An aromatic ring-containing homopolymer composed of a monomer constituting an aromatic ring-containing polymer contained as a block portion of a block copolymer or a graft portion of a graft copolymer, or a poly (meth) acrylate homopolymer composed of a monomer constituting a poly (meth) acrylate The number average molecular weight is preferably 1000 or more from the viewpoint of phase separability, preferably 500,000 or less, more preferably 300,000 or less, from the viewpoint of suppressing the viscosity of the resin composition. From the viewpoint of compatibility with the block copolymer or graft copolymer, the molecular weights of the aromatic ring-containing homopolymer and poly (meth) acrylate homopolymer are the aromatic rings contained as the block portion of the block copolymer or the graft portion of the graft copolymer, respectively. The molecular weight is preferably lower than the molecular weight of the containing polymer portion and the poly (meth) acrylate portion.

  The above resin composition is dissolved in a solvent to form a solution, and then applied to the surface 1 a of the substrate 1. Subsequently, the resin composition is dried, and the solvent is volatilized to form the resin composition layer 2.

  Any solvent can be used as long as it can dissolve the above resin composition. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, cyclopentanone, Cyclohexanone, isophorone, N, N-dimethylacetamide, dimethylimidazolinone, tetramethylurea, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, Propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA), methyl lactate, ethyl lactate, butyl lactate, Chill-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, methyl 3-methoxypropionate and the like. These can be used alone or in admixture of two or more. Specific preferred examples include N-methylpyrrolidone, cyclopentanone, cyclohexanone, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, PGMEA and the like. The mass ratio of the resin composition to the solution is preferably 1 to 30% by mass.

  In addition, as a method of applying the resin composition solution to the surface 1a of the substrate 1, a spin coater, a bar coater, a blade coater, a curtain coater, a spray coater, a method of applying by an ink jet method, a screen printer, a gravure printer, an offset A method of printing with a printing machine or the like can be given.

  Next, the obtained coating film is heat-dried or vacuum-dried by air drying, oven, hot plate or the like to volatilize the solvent. The film thickness of the resin composition layer 2 after volatilization of the solvent is preferably about 20 to 1000 nm from the viewpoint of obtaining a self-assembled pattern with a pitch of 20 to 1000 nm. In the present invention, the normal pitch is the same as the film thickness of the resin composition layer 2 or larger than the film thickness of the resin composition layer 2. The film thickness of the resin composition layer 2 can be determined by a contact method in which a film is scratched and a terminal is brought into contact with the surface to measure the step, or a non-contact method using ellipsometry.

  Next, in FIG. 1B, the resin composition layer 2 is heated in the presence of oxygen or nitrogen. As a method of heating the resin composition layer 2 for each substrate, there are roughly classified a method of transferring heat directly from the lower side of the substrate like a hot plate and a method of convection of a high-temperature gas like an oven. Can do.

  The temperature of the step of volatilizing the solvent is preferably in the range of 100 ° C. lower than the boiling point of the solvent to the boiling point of the solvent, and the temperature of the subsequent heating step is preferably in the range of 130 ° C. or higher and 280 ° C. or lower. Heating may be performed in air or under nitrogen, but when heated to 200 ° C. or higher in air, thermal decomposition occurs and the pitch of the self-assembled pattern increases.

  By heating the resin composition layer 2, the aromatic ring-containing polymer portion and the poly (meth) acrylate portion are microphase-separated and self-organized. FIG. 1B shows a self-organizing structure 2a. The self-assembled structure 2 a is an island sea structure composed of an aromatic ring-containing polymer portion 3 and a poly (meth) acrylate portion 4.

  Subsequently, one phase of the aromatic ring-containing polymer portion 3 and the poly (meth) acrylate portion 4 is removed. At this time, if removal of one phase is performed by dry etching, the cost is increased. Therefore, in the present invention, one phase is removed by a chemical solution. At this time, when irradiated with UV light, poly (meth) acrylate is selectively decomposed to lower the molecular weight, so that it becomes soluble in a polar organic solvent such as acetic acid. By utilizing this property and dissolving in a chemical solution after UV irradiation, only the poly (meth) acrylate portion 4 can be selectively removed, leaving only the pattern of the aromatic ring-containing polymer portion 3.

  The wavelength of the UV light irradiated here is preferably 300 nm or less, and more preferably 200 nm or less. The irradiation time can take a value between 10 seconds and 5 hours. Examples of the chemical solution for selectively dissolving the low molecular weight poly (meth) acrylate portion 4 include carboxylic acids such as acetic acid, alcohols and ketones, but from the viewpoint that the aromatic ring-containing polymer portion 3 does not dissolve. Acetic acid is preferably used. Further, as shown in FIG. 1C, since the surface 1a of the substrate 1 is exposed by selectively dissolving the poly (meth) acrylate portion 4, the material of the surface 1a of the substrate 1 is taken into consideration. It is preferable to select a chemical solution having a small influence on 1.

  FIG. 1C illustrates a self-assembled pattern 2 b in which the poly (meth) acrylate portion 4 is selectively dissolved and the aromatic ring-containing polymer portion 3 is left on the substrate 1. The self-organized pattern 2b is a micro unevenness obtained by removing one polymer part from the self-organized structure 2a having an island-sea structure of an aromatic ring-containing polymer part 3 and a poly (meth) acrylate part 4 by the action of microphase separation. Refers to the pattern.

  As shown in FIG. 1C, a space 5 where the surface 1a of the substrate 1 is exposed is formed in the portion where the poly (meth) acrylate portion 4 is removed.

  As shown in FIG. 1C, the self-organized pattern 2b remains as a random pattern, but the pattern pitch is 20 to 1000 nm on average, preferably about 100 to 1000 nm. In particular, in the present invention, the degree of freedom of pitch width adjustment can be improved by adding a homopolymer to the block portion or graft portion of the block copolymer or graft copolymer as the resin composition. The pitch can be adjusted freely.

  Subsequently, as shown in FIG. 2A, the inorganic oxide precursor solution 6 is filled into the space 5 of the self-assembled pattern 2 b made of the aromatic ring-containing polymer portion 3.

The inorganic oxide and precursor will be described. The inorganic oxide layer is preferably an oxide of Si, Ti, Zr, Cr, Zn, Sn, B, In, Al, and Mg. _{Specifically,} mention may be made of _{SiO 2, TiO 2, ZrO 2} , CrO 2, ZnO, SnO 2, B 2 O 3, In 2 O 3, Al 2 O 3, MgO or the like. Of these, SiO ₂ , TiO ₂ , ZrO ₂ , and Al ₂ O ₃ are preferably used. Depending on the structure of the precursor, these may not be 100% oxides (including organic groups). The precursor is an alkoxide or hydroxide of these metal elements. In the case of Si, there is also a precursor known as spin-on-glass (SOG), which is a solvent-soluble siloxane oligomer. These precursors become oxides when heated to 200 ° C. or higher, preferably 300 ° C. or higher.

  As shown in FIG. 2A, the precursor solution 6 of the inorganic oxide is preferably applied so as not to exceed the pattern height H of the aromatic ring-containing polymer portion 3. When the precursor solution 6 exceeds the pattern height H of the aromatic ring-containing polymer portion 3, the upper surface of the aromatic ring-containing polymer portion 3 is covered with the precursor solution 6, and the aromatic ring-containing polymer portion 3 is appropriately treated in a later step. This is because it cannot be removed from the base material 1 and a fine uneven structure cannot be formed on the base material 1 with a high yield.

  Moreover, as a kind of solvent used for the precursor solution 6, the solvent which does not dissolve the aromatic ring containing polymer part 3 is preferable. In addition, since the aromatic ring-containing polymer portion 3 is generally hydrophobic and the inorganic oxide precursor is hydrophilic, a small amount of a surfactant is added to the inorganic oxide precursor solution 6 for uniform application. It is desirable to do. As a method of applying the precursor solution 6, a spin coater, a bar coater, a blade coater, a curtain coater, a spray coater, a method of applying by an inkjet method, a method of printing by a screen printer, a gravure printer, an offset printer, or the like. Can be mentioned.

  After application of the precursor solution 6 of the inorganic oxide, pre-baking is performed at 200 ° C. or less to drive off the solvent of the precursor solution 6. Subsequently, the precursor of the inorganic oxide is transformed into the inorganic oxide 7 by heating the precursor solution 6 to 200 ° C. or higher, preferably 300 ° C. or higher. At this time, as shown in FIG. 2B, the self-assembled pattern 2b composed of the aromatic ring-containing polymer portion 3 can be thermally decomposed and removed.

  In the volatilization of the solvent and the subsequent heating step, the method of heating the coating film together with the substrate is roughly divided into a method of directly transferring heat from the lower side of the substrate 1 like a hot plate, and a high-temperature gas like an oven. The method of convection can be mentioned.

  By the manufacturing method described above, the fine uneven structure 10 made of the inorganic oxide 7 can be formed on the substrate 1 as shown in FIG. 2B.

  Here, the fine concavo-convex structure 10 made of the inorganic oxide 7 remains after removing one phase from the self-assembled structure 2a formed by self-assembly of the resin composition containing the block copolymer or the graft copolymer. The self-organized pattern 2b composed of the different phases is inverted. However, the coating film thickness (filling film thickness) of the precursor solution 6 of the inorganic oxide also affects the pitch, and the pitch can be increased by increasing the coating film thickness.

  The height of the fine relief structure 10 is determined by the coating thickness of the resin composition containing a block copolymer or a graft copolymer, and increases as the coating thickness increases.

  The shape of the fine relief structure 10 shown in FIG. 2B is not particularly limited, such as a dot shape, a hole shape, or a line shape. The pitch of the fine relief structure 10 is 20 to 1000 nm, preferably 100 to 1000 nm. The pitch can be measured by the distance between the centers of adjacent convex portions (distance between centroids) or the distance between centers of adjacent concave portions (distance between centroids). For example, when a substrate with a fine concavo-convex structure is used as an optical element, by setting the pitch of the fine concavo-convex structure 10 to 20 to 1000 nm, preferably 100 to 1000 nm, it will act as a diffraction grating for visible light. , The ability to improve the luminance with respect to visible light can be improved.

  The height of the fine relief structure 10 is 20 to 1000 nm, preferably 50 to 1000 nm. The height of the fine concavo-convex structure 10 is 20 to 1000 nm, preferably 20 to 1000 nm, thereby facilitating the production of the fine concavo-convex structure 10 and improving the ability to improve luminance when a light-emitting element is formed. Can do.

  The fine concavo-convex structure 10 is a random fine pattern. That is, the above-described pitch is not substantially constant between the convex portions or the concave portions, and varies. Therefore, the fine concavo-convex structure 10 in the present invention is distinguished from the regularly arranged fine concavo-convex structure. The pitch of the fine concavo-convex structure 10 described above can be expressed as an average pitch of a predetermined number of fine concavo-convex structures 10. For example, the average pitch can be obtained from the pitch between 10 convex portions.

  The characteristic part of the manufacturing method of the base material 1 provided with the fine relief structure 10 in the present invention is that a self-organized pattern of a block copolymer or a graft copolymer is formed, and one phase formed in the self-organized pattern is formed by a chemical solution. Examples include applying an inorganic oxide precursor to the removed space, and changing the inorganic oxide precursor to an inorganic oxide by heating and removing the self-organized pattern.

  Thereby, the formation of the self-assembled pattern 2b and the fine concavo-convex structure 10 made of an inorganic oxide can be formed without using expensive dry etching that requires a vacuum process. In addition, by setting the heating for changing the precursor of the inorganic oxide to the inorganic oxide, the temperature is set to a temperature at which the self-assembled pattern can be thermally decomposed (specifically, 200 ° C. or higher, preferably 300 ° C. or higher). The step of changing the precursor of the inorganic oxide to the inorganic oxide and the step of removing the self-assembled pattern can be performed simultaneously, and the manufacturing process can be simplified. Further, in the present invention, unlike the non-patent document 1, since the inorganic oxide precursor is not compatible with the block copolymer or graft copolymer, the structures of the inorganic oxide precursor, block copolymer and graft copolymer are not included. -The degree of freedom of material selection can be increased.

  As described above, in the present invention, a substrate with a fine concavo-convex structure can be accurately formed at low cost.

  Hereinafter, the present invention will be described in more detail based on examples carried out to clarify the effects of the present invention. In addition, the material in the following Example, use composition, a process process, etc. are illustrations, and can be implemented changing suitably. Other modifications can be made without departing from the scope of the present invention. Therefore, the present invention is not limited at all by the following examples.

  First, synthesis examples of a block copolymer, an aromatic ring-containing homopolymer and a poly (meth) acrylate homopolymer comprising the block component are shown.

<Synthesis of block copolymer>
[Synthesis Example 1]
980 g of tetrahydrofuran (THF) dehydrated and degassed as a solvent in a 2 L flask, 0.8 ml of hexane solution (about 0.16 mol / L) of n-butyllithium (n-BuLi) as an initiator, and dehydrated and dehydrated as a monomer 20 g of styrene was added and stirred for 30 minutes while cooling to −78 ° C. in a nitrogen atmosphere. Then, 34 g of methyl methacrylate dehydrated and degassed as the second monomer was added and stirred for 4 hours. Thereafter, the reaction solution was added to a container containing 3 L of denatured alcohol (Solmix (registered trademark) AP-1 manufactured by Nippon Alcohol Sales Co., Ltd.) while stirring, and the precipitated polymer was vacuum-dried overnight at room temperature.

  The dried polymer was filled into a Soxhlet extractor, and by-product polystyrene was extracted using cyclohexane as a solvent. From the analysis by GPC, this byproduct polystyrene was identified as polystyrene having a number average molecular weight (Mn) of 366,000 in terms of standard polystyrene. This byproduct polystyrene is the one in which the terminal is inactivated at the end of polymerization of the block copolymer during synthesis of the block copolymer and cannot react with methyl methacrylate, and is the same as the molecular weight of the polystyrene block part in the block copolymer. is there.

The GPC apparatus, column, and standard polystyrene used are as follows.
Device: HLC-8020 manufactured by Tosoh Corporation
Eluent: Tetrahydrofuran 40 ° C
Column: Tosoh Co., Ltd. TSK (registered trademark) gel G5000HHR / G4000HHR / G3000HHR / G2500HHR In-line flow rate: 1.0 ml / min
Reference material for molecular weight calibration: TSK (registered trademark) standard polystyrene (12 samples) manufactured by Tosoh Corporation

From the result of the nuclear magnetic resonance (NMR) analysis, the molar ratio of the PS portion and the PMMA portion of the block copolymer was 2.13. The NMR apparatus and solvent used are as follows.
Apparatus: JNM-GSX400 FT-NMR manufactured by JEOL Ltd.
Solvent: deuterated chloroform

  Combined with the GPC results, the block copolymer, the main product, was identified as having a PS moiety Mn of 366,000 and a PMMA moiety Mn of 778,000. This was designated as BC-1.

<Synthesis of aromatic ring-containing homopolymer>
[Synthesis Example 2]
In a 500 ml flask, 180 g of methyl ethyl ketone (hereinafter also referred to as MEK) as a solvent, 2.36 g (0.0144 mol) of AIBN as an initiator, and 30.0 g (0.288 mol) of styrene as a monomer were heated to 70 ° C. in a nitrogen stream. The mixture was stirred for 6 hours and then allowed to cool to room temperature. The reaction mixture was added to 2 L of a mixed solution of Solmix AP-1 and water having a weight ratio of 2: 1 with stirring to precipitate a polymer. The mixture was stirred for 1 hour and then filtered using a filter paper, and the solid content was vacuum-dried overnight. The molecular weight and molecular weight distribution were measured by GPC under the same conditions as in Synthesis Example 1. As a result, Mw (weight average molecular weight) was 3,200, and molecular weight distribution (Mw / Mn) was 1.38. This was designated as PS-1.

<Synthesis of poly (meth) acrylate homopolymer>
[Synthesis Example 3]
In a 1 L flask, 390 g of MEK as a solvent, 37.4 g (0.16 mol) of 2,2′-azobis (dimethyl isobutyrate) as an initiator, and 65 g (0.65 mol) of methyl methacrylate as a monomer were placed in a nitrogen stream. The mixture was stirred for 5 hours while heating to 70 ° C., and then allowed to cool to room temperature.

  The reaction mixture was added to 3 L of hexane with stirring to precipitate a polymer. After stirring this for 1 hour, it filtered using the filter paper and solid content was vacuum-dried at room temperature overnight. As a result of measuring the molecular weight and molecular weight distribution by GPC, Mw (weight average molecular weight) was 4,000, and molecular weight distribution (Mw / Mn) was 1.70 (in this case, GPC was the same as in Synthesis Example 1) Although measured, standard PMMA MH-10 (10 samples) manufactured by Polymer Laboratories was used as a molecular weight calibration substance). This was designated as PMMA-1.

  Next, a process of forming a resin composition layer using the synthesized polymer and forming a fine concavo-convex structure made of an inorganic oxide using a self-assembly pattern formed by self-assembly of the resin composition layer Show.

[Example 1]
(Formation of self-organizing patterns)
BC-1, PS-1, and PMMA-1 obtained in the previous synthesis example were weighed 5 g, 2.5 g, and 5 g, respectively, and PGMEA was added to prepare a 6.26% by mass solution as a resin composition. This solution was spin-coated on a silicon wafer at 1600 rpm for 30 seconds and pre-baked at 110 ° C. for 90 seconds. It was 350 nm when the film thickness of this thin film was measured using Nanospec AFT3000T made by Nanometrics Japan Co., Ltd. Next, heat at 250 ° C for 8 hours while flowing nitrogen and air in a cure oven (CHL-21CD-S type manufactured by Koyo Thermo System Co., Ltd.) so that the oxygen concentration is 2400 ppm. did. Thereafter, the mixture was cooled to room temperature, and the pattern of the resin composition was observed with AFM. When this sea-island structure pattern was analyzed using image analysis software A image-kun (manufactured by Asahi Kasei Engineering Co., Ltd.), the average distance (pitch) between the island and the island was 350 nm.

  After irradiating an excimer lamp with a wavelength of 172 nm in the air for 1 minute to the resin composition having the sea-island structure pattern, each substrate is selectively removed by dipping in acetic acid for 1 minute. did. As described above, a self-organized pattern having a space part from which the PMMA part was removed and composed of the remaining PS part was formed.

(Formation of fine relief structure consisting of inorganic oxide layer)
Subsequently, as a silica precursor, SOG T-7 (manufactured by Tokyo Ohka Kogyo Co., Ltd., propylene glycol monopropyl ether solvent), surfactant DBE-621 (Gerest Co., Ltd.) at a ratio of 1% with respect to the solid content of SOG. The solution to which the product was added was spin-coated at 3000 rpm for 30 seconds. Thereby, the space part of a self-organization pattern can be filled with the precursor solution of silica. Further, the coating amount of the precursor solution was adjusted so that the height of the silica precursor solution filled in the space was lower than the height of the self-assembled pattern.

  Next, it was heated at 350 ° C. for 30 minutes while flowing nitrogen into a curing oven (CHL-21CD-S type manufactured by Koyo Thermo System Co., Ltd.). After cooling to room temperature and observing the surface pattern with AFM, a fine concavo-convex structure with holes in the silica layer was observed. In addition, the self-organization pattern which consists of PS parts was not seen. And when the fine concavo-convex structure of a silica layer was analyzed using image analysis software A image-kun (made by Asahi Kasei Engineering Co., Ltd.), the average distance (pitch) between holes was 300 nm.

[Example 2]
In Example 2, the experiment was performed in the same manner as in Example 1 except that the rotation speed during spin coating of SOG T-7 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was changed from 3000 rpm to 1000 rpm. In Example 2, a fine concavo-convex structure of a silica layer having an average distance between the centers of gravity (pitch) of 400 nm was obtained.

[Comparative Example 1]
(Formation of silica layer)
First, SOG T-7 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) is spin-coated at 1000 rpm for 30 seconds on a silicon wafer, and nitrogen is passed through a cure oven (CHL-21CD-S type manufactured by Koyo Thermo System Co., Ltd.). The mixture was heated at 350 ° C. for 30 minutes. Thereby, a silica layer having a thickness of 50 nm was formed.

(Formation of self-organizing patterns)
BC-1, PS-1, and PMMA-1 obtained in the previous synthesis example were weighed 5 g, 2.5 g, and 5 g, respectively, and PGMEA was added to prepare a 6.26% by mass solution as a resin composition. This solution was spin-coated at 1600 rpm for 30 seconds on the surface of the silica layer formed on the silicon wafer, and pre-baked at 110 ° C. for 90 seconds. The film thickness of the resin composition layer thus formed was 350 nm when measured using NanoSpec AFT3000T manufactured by Nanometrics Japan K.K. Next, while flowing nitrogen and air in a cure oven (CHL-21CD-S type manufactured by Koyo Thermo System Co., Ltd.) so that the oxygen concentration is 2400 ppm, the resin composition layer is 250 Heated at 0 ° C. for 8 hours. Thereafter, the mixture was cooled to room temperature, and the pattern of the resin composition layer was observed by AFM. As a result, a pattern was found in which the polystyrene portion was an island and the polymethyl methacrylate portion was a sea. When this sea-island structure pattern was analyzed using image analysis software A image-kun (manufactured by Asahi Kasei Engineering Co., Ltd.), the average distance (pitch) between the island and the island was 350 nm.

  The resin composition layer on which the sea-island structure pattern is formed is irradiated with an excimer lamp having a wavelength of 172 nm in the air for 1 minute, and then is dipped in acetic acid for 1 minute for each substrate, so that only the PMMA portion is selectively selected. Removed. As described above, a self-organized pattern having a space part from which the PMMA part was removed and composed of the remaining PS part was formed.

(Pattern transfer to inorganic oxide layer)
Next, using a plasma etching apparatus, the silica layer was dry etched for 3 minutes using the self-assembled pattern as a mask under the conditions of power 300 W, pressure 1 Pa, gas CF ₄ 50 SCCM.

  Thus, it was found that a fine uneven structure of a silica layer having a pitch of 350 nm and a height of 50 nm could be formed on the silicon wafer.

  However, in Comparative Example 1, a dry etching process was required to form a fine relief structure in the inorganic oxide layer.

  In the present invention, the base material having a fine concavo-convex structure formed by utilizing a self-organized pattern such as a block copolymer is an intermediate for transferring the fine concavo-convex structure to the surface layer of the base material. The uneven structure can be applied as a refractive index control layer of a light-emitting element, a mold, or the like.

DESCRIPTION OF SYMBOLS 1 Base material 2 Resin composition layer 2a Self-assembled structure 2b Self-assembled pattern 3 Aromatic ring containing polymer part 4 Poly (meth) acrylate part 5 Space part 6 Precursor solution 7 Inorganic oxide 10 Fine uneven structure

Claims (7)

Forming a resin composition layer containing a block copolymer or a graft copolymer on a substrate;
Self-organizing the resin composition layer;
Removing one phase of the resin composition layer phase-separated by the self-assembly with a chemical solution to form a self-assembly pattern consisting of the other phase;
Filling the space of the self-assembled pattern formed by removing the one phase with an inorganic oxide precursor;
A step of transforming the precursor of the inorganic oxide into the inorganic oxide by heating, removing the self-assembled pattern, and forming a fine concavo-convex structure made of the inorganic oxide on the substrate;
The manufacturing method of the base material with a fine concavo-convex structure characterized by having.   The method for producing a substrate with a fine relief structure according to claim 1, wherein the heating temperature is 200 ° C or higher.   The method for producing a substrate with a fine concavo-convex structure according to claim 1, wherein the heating temperature is 300 ° C. or higher.   The method for producing a substrate with a fine concavo-convex structure according to any one of claims 1 to 3, wherein the resin composition layer is exposed to UV light before the one phase is removed with a chemical solution. .   The pitch of the fine concavo-convex structure is 20 to 1000 nm, and the height of the fine concavo-convex structure is 20 to 1000 nm, The production of a substrate with a fine concavo-convex structure according to any one of claims 1 to 4 Method.   The pitch of the fine concavo-convex structure is 100 to 1000 nm, and the height of the fine concavo-convex structure is 100 to 1000 nm, The production of a substrate with a fine concavo-convex structure according to any one of claims 1 to 4 Method. A fine uneven structure comprising a substrate and a fine uneven structure formed on the substrate, wherein the fine uneven structure is formed by the manufacturing method according to claim 1. Structured substrate.

Images