JP2014047217A - Thin polymer film, microstructure, and method for manufacturing both - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin polymer film capable of unprecedentedly improving the processing precision of a substrate.SOLUTION: The method for manufacturing a thin polymer film provided by the present invention comprises a first step of configuring, atop a substrate, a polymer layer including a high-molecular-weight block copolymer having at least first and second segments and a second step of regularly arraying, atop the substrate by inducing the microphase separation of the polymer layer, multiple microdomains each having the second segment within a continuous phase consisting of the first segment; the high-molecular-weight block copolymer includes a silsesquioxane skeleton within the first segment; the first segment accounts, in terms of volume percentage, for 53% to 63% of the volume occupied by the high-molecular-weight block copolymer within the polymer layer; the microdomains have cylindrical shapes arrayed in parallel so as to extend along the substrate.

Description

  The present invention relates to a polymer thin film having a microstructure in which a polymer block copolymer is formed by microphase separation on a substrate, a microstructure obtained using the polymer thin film, and a method for producing the same. .

In recent years, with the miniaturization and high performance of electronic devices, energy storage devices, sensors, and the like, there is an increasing need to form a fine regular array pattern having a size of several nanometers to several hundred nanometers on a substrate. Therefore, establishment of a process capable of manufacturing a fine regular array pattern (hereinafter simply referred to as “fine structure”) with high accuracy and low cost is required.
As a processing method of such a fine structure, a top-down method represented by lithography, that is, a method of finely engraving a bulk material is generally used. For example, photolithography used for semiconductor microfabrication such as LSI manufacturing is a typical example.

  However, such a top-down approach increases the manufacturing cost by increasing the size of the apparatus and the complexity of the process as the fineness of the fine structure increases. In particular, when the processing size of the fine structure becomes as fine as several tens of nanometers, it is necessary to use an electron beam or deep ultraviolet rays for patterning, and a huge investment is required for the apparatus. In addition, when it becomes difficult to form a fine structure using a mask, the direct drawing method must be applied, and thus there is a problem that the processing throughput is significantly reduced.

  Under such circumstances, a process that applies a phenomenon in which a substance naturally forms a structure, that is, a so-called self-organization phenomenon, has attracted attention (for example, see Patent Documents 1 and 2). In particular, the process using microphase separation of the polymer block copolymer is an excellent process in that it can form microstructures having various shapes of several tens to several hundreds of nanometers by a simple coating process. . For example, when different types of polymer segments in the polymer block copolymer are not mixed with each other (incompatible), these polymer segments are microphase-separated with each other, resulting in a spherical shape, a cylinder shape, etc. A microphase separation structure is formed in which the microdomains are regularly arranged in the continuous phase.

  A fine structure forming method (microstructure manufacturing method) using this microphase-separated structure is as follows. In this formation method, for example, a coating of a polymer block copolymer (hereinafter sometimes referred to as a polymer layer) made of a combination of polystyrene and polybutadiene, polystyrene and polyisoprene, polystyrene and polymethyl methacrylate, or the like is formed on a substrate. To microphase separation. Then, one microdomain of the microphase separation structure in the obtained polymer thin film is removed by etching or the like.

  Then, by etching the substrate using the remaining polymer thin film from which the microdomains have been removed as a mask (resist), holes and lines and spaces having a shape corresponding to the planar shape of the removed microdomains are formed on the substrate. be able to. Examples of the shape of the microdomain that forms a hole or a line and space on the substrate include a spherical shape, a cylinder shape oriented upright on the substrate, and a cylinder shape oriented parallel to the substrate. However, when forming microdomains (for example, cylinder-shaped) oriented upright on the substrate, it is essential to control the energy at the interface between the substrate interface and the air interface side. If it is used, it becomes difficult to achieve upright orientation. Therefore, a microphase separation structure (polymer thin film) with spherical microdomains is used for the holes, and a microphase separation structure (polymer thin film) with cylinder-shaped microdomains aligned parallel to the substrate is used for the line and space. Is easier to use.

US Pat. No. 6,746,825 US Pat. No. 6,926,953

In recent years, a polymer thin film having a microphase-separated structure whose size has been further miniaturized has been desired due to a demand for further miniaturization and higher performance of electronic devices and the like.
On the other hand, in the conventional polymer thin film having a microphase separation structure (see, for example, Patent Document 1 and Patent Document 2), the size of the microdomain removed in the process of manufacturing the mask is smaller than the interval between the microdomains. . Therefore, the conventional polymer thin film has a problem that it is impossible to accurately process a size of 10 tens of nanometers or less. In the conventional polymer thin film, when trying to increase the size of the microdomain with respect to the interval between the microdomains, the microphase separation structure changes into a cylindrical shape when the microdomain is spherical and a lamellar shape when the microdomain is cylindrical. Will cause new problems. In other words, the conventional polymer thin film has a problem in that the processing accuracy of the substrate cannot be sufficiently improved due to the upper limit of the diameter of the microdomain that is naturally defined, so as to meet the above requirement.

  Therefore, an object of the present invention is to provide a polymer thin film that can improve the processing accuracy of a substrate as compared with the conventional art, a microstructure obtained by using this polymer thin film, and a method for manufacturing the same. .

  The method for producing a polymer thin film of the present invention that solves the above problems includes a first step of disposing a polymer layer containing a polymer block copolymer having at least a first segment and a second segment on a substrate; A second step in which a molecular layer is microphase-separated, and a plurality of microdomains having the second segment as a component are regularly arranged on the substrate in a continuous phase having the first segment as a component. In the method for producing a polymer thin film, the polymer block copolymer has a silsesquioxane skeleton in the first segment, and the polymer layer occupies the volume occupied by the polymer block copolymer in the polymer layer. The volume percentage of the first segment is 53% to 63%, and the microdomains are in the shape of a cylinder arranged in parallel so as to extend along the substrate.

  Moreover, the method for producing a polymer thin film of the present invention that solves the above-described problem includes a first step of disposing a polymer layer containing a polymer block copolymer having at least a first segment and a second segment on a substrate, A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component; The polymer block copolymer has a silsesquioxane skeleton in the first segment, and the polymer layer occupies the volume occupied by the polymer block copolymer. The volume percentage of the first segment is 70% to 75%, and the microdomain is spherical.

  Moreover, the manufacturing method of the microstructure of the present invention that solves the above problems includes a first step of disposing a polymer layer including a polymer block copolymer having at least a first segment and a second segment on a substrate; A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component; And a third step of removing one of the continuous phase and the microdomain of the polymer layer, wherein the polymer block copolymer has silsesquiskies in the first segment. The volume percentage of the first segment is 53% to 63% of the volume occupied by the polymer block copolymer in the polymer layer. Wherein the emissions are cylinder shaped to parallel so as to extend along the substrate.

  Moreover, the manufacturing method of the microstructure of the present invention that solves the above problems includes a first step of disposing a polymer layer including a polymer block copolymer having at least a first segment and a second segment on a substrate; A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component; And a third step of removing one of the continuous phase and the microdomain of the polymer layer, wherein the polymer block copolymer has silsesquiskies in the first segment. The volume percentage of the first segment is 70% to 75% of the volume occupied by the polymer block copolymer in the polymer layer. Down to being a spherical shape.

  Moreover, the polymer thin film of the present invention that solves the above-mentioned problems is obtained by the above-described method for producing a polymer thin film.

  Moreover, the microstructure of the present invention that solves the above-described problems is obtained by the above-described method for manufacturing a microstructure.

  ADVANTAGE OF THE INVENTION According to this invention, the polymer thin film which can improve the processing precision of a board | substrate conventionally, the microstructure obtained using this polymer thin film, and these manufacturing methods can be provided.

(A) is the partial expansion perspective view which has a fracture surface in part for demonstrating the structure of the polymer thin film which concerns on embodiment of this invention, (b) is the micro phase of the polymer thin film of (a). It is the elements on larger scale which partially showed signs that a separation structure was seen from the surface side of a polymer thin film. (A) is a partial enlarged perspective view partially having a fractured surface for explaining another configuration of the polymer thin film according to the embodiment of the present invention, and (b) is a diagram of the polymer thin film of (a). It is the elements on larger scale which partially showed signs that a micro phase separation structure was seen from the surface side of a polymer thin film. (A) is a schematic cross-sectional view of a state in which a block copolymer is applied to a substrate in producing the polymer thin film in the present invention, and (b) is a coating film (high) of the block copolymer of (a). FIG. 2 is a schematic cross-sectional view showing a state in which a molecular layer is microphase-separated to form a regular structure. The conceptual diagram which shows the mode of the 1st segment in the polymer block copolymer used for formation of the polymer thin film of this invention, and the 2nd segment for the case where the 2nd segment formed the spherical micro domain as an example. is there. (A)-(f) is explanatory drawing of the process of forming the patterned chemical modification layer on the surface of the board | substrate used for formation of the polymer thin film of this invention. (A)-(c) is a cross-sectional schematic diagram which shows the aspect of the patterned chemical modification layer arrange | positioned on a board | substrate. (A)-(d) is process drawing for demonstrating the manufacturing method of the microstructure obtained using the polymer thin film of this invention. (A) is the SEM image of the polymer thin film produced in Example 1 of this invention, (b) is the SEM image of the microstructure obtained using the polymer thin film of (a). (C) is the SEM image of the polymer thin film produced in Comparative Example 1 of the present invention, and (d) is the SEM image of the microstructure obtained using the polymer thin film of (c). (A) is the SEM image of the polymer thin film produced in Example 4 of this invention, (b) is the SEM image of the microstructure obtained using the polymer thin film of (a). (C) is the SEM image of the polymer thin film produced in Comparative Example 4 of the present invention, and (d) is the SEM image of the microstructure obtained using the polymer thin film of (c). It is a schematic plan view which shows typically the structure of the surface of the magnetic-recording medium (fine structure) produced in Example 7 of this invention.

Next, embodiments of the polymer thin film of the present invention and the microstructure obtained by using the polymer thin film will be described in detail with reference to the drawings as appropriate.
The polymer thin film having a conventional microphase separation structure, for example, a polymer thin film of a polymer block copolymer composed of a combination of polystyrene and polybutadiene, polystyrene and polyisoprene, polystyrene and polymethyl methacrylate, etc. There was a problem that processing of nanometer size or less could not be performed accurately. In other words, when trying to increase the size of the microdomain with respect to the microdomain spacing in the polymer thin film to be formed, the microphase separation structure is used when the polymer block copolymer coating (polymer layer) is microphase separated. One of the factors is that the desired spherical shape is changed to a cylinder shape (or an initial cylinder shape to a lamella shape), and the microdomain size with respect to the microdomain interval cannot be increased substantially.
On the other hand, the inventors of the present invention have compared the change point (change region) to be described later with respect to the conventional polymer thin film in the polymer thin film made of a predetermined polymer block copolymer described later. Thus, the present invention has been found by newly finding out that it has shifted.

The polymer thin film of the present invention has a continuous phase formed by microphase separation of a predetermined polymer block copolymer described later, and microdomains regularly arranged in the continuous phase. . Then, the second segment of the polymer block copolymer is formed out of the volume occupied by the polymer block copolymer in the coating film (polymer layer) of the polymer block copolymer for obtaining this polymer thin film. The volume percentage of the first segment of the polymer block copolymer that forms the continuous phase is controlled in accordance with the shape of the microdomain (for example, spherical shape, cylinder shape, etc.) to be within a predetermined range described later. It is the main feature.
Below, it demonstrates in order of the polymer thin film, the manufacturing method of this polymer thin film, the microstructure obtained using this polymer thin film, and the manufacturing method of this microstructure.

(Polymer thin film)
FIG. 1 (a) is a partially enlarged perspective view partially having a fractured surface for explaining the configuration of a polymer thin film according to an embodiment of the present invention, and FIG. 1 (b) is a diagram of FIG. 1 (a). It is the elements on larger scale which partially showed signs that the micro phase separation structure of the polymer thin film was seen from the surface side of the polymer thin film.
As shown in FIG. 1A, the polymer thin film M having a fine structure according to the present embodiment has a microphase separation structure composed of a continuous phase 102 and a microdomain 101. As will be described later, the polymer thin film M is a polymer layer formed by applying a polymer block copolymer on the substrate 104 and formed by subjecting the polymer block copolymer to microphase separation. It is.
Although not shown, the substrate 104 shown in FIG. 1A has a patterned chemical modification layer on its surface, which will be described in detail later.

  The microdomains 101 are arranged in the continuous phase 102 so as to be regularly arranged along the surface direction of the surface of the substrate 104. More specifically, the spherical microdomain 101 formed in the polymer thin film M has a hexagonal close-packed structure along the surface direction of the surface of the substrate 104 as shown in FIG. Is arranged. In FIG. 1, a spherical structure is taken as an example of the microdomain structure. However, as will be described later, the microdomain structure may be a cylinder.

In FIG. 1B, the symbol d ₀ is the natural period of the microdomain 101 and is an eigenvalue determined according to the type, composition, molecular weight and the like of the polymer block copolymer described later for forming the polymer thin film M. It is. Arrangement interval of the microdomains 101 is determined by the natural period d _0. Reference sign D ₀ is the diameter of the spherical microdomain 101. A symbol L ₀ is an interval between the micro domains 101. When the spherical microdomains are arranged in a hexagonal lattice, the code L ₀ and the code d ₀ have a relationship of L ₀ = 2 / √3 × d ₀ .
Incidentally, the interval L ₀ between the spherical microdomains 101 is preferably 5 to 25 nm.

The polymer thin film M having the spherical microdomain 101 shown in FIGS. 1A and 1B has a diameter D _{0 in} a plan view of the spherical microdomain 101, in other words, as will be described in detail later. For example, the diameter D ₀ of the planar shape (microcircular shape) of the microdomain 101 viewed from the normal direction of the substrate 104 is preferably 55% so that the distance L ₀ between the microcircular shapes is 53% or more. Control is performed as described above.
That is, the polymer thin film M having the spherical microdomain 101 is configured to satisfy the relational expression of 100 · D ₀ / L ₀ ≧ 53, preferably 100 · D ₀ / L ₀ ≧ 55.

FIG. 2A to be referred to next is a partially enlarged perspective view partially having a fracture surface for explaining another configuration of the polymer thin film according to the embodiment of the present invention, and FIG. FIG. 3 is a partially enlarged plan view partially showing a state where the microphase separation structure of the polymer thin film in FIG. 2A is viewed from the surface side of the polymer thin film.
The microdomain 101 (see FIG. 1 (a)) has a spherical shape, but the microdomain 101 in the present invention has a cylindrical shape as shown in FIGS. 2 (a) and 2 (b). You can also. More specifically, the microdomain 101 is formed so as to extend along the surface direction of the surface of the substrate 104 in the continuous phase 102. The micro domains 101 are arranged in parallel at equal intervals along the surface direction of the surface of the substrate 104.
Incidentally, the shape of the continuous phase 102 has various shapes corresponding to the spherical micro domain 101 (see FIG. 1A), the cylindrical micro domain 101 (see FIG. 2A), and the like. Needless to say you get.

In FIG. 2B, the symbol D ₀ is the diameter of the cylindrical micro domain 101. The diameter D ₀ of the cylindrical micro domain 101 corresponds to the width W ₀ of the planar shape (strip shape) of the micro domain 101 viewed from the normal direction of the substrate 104. A symbol L ₀ is an interval between the micro domains 101. When cylinder-shaped microdomains are arranged in parallel in a planar shape, the code L ₀ and the code d ₀ have a relationship of L ₀ = d ₀ .
Incidentally, the distance L ₀ between the cylindrical microdomains 101 is preferably 5 to 25 nm.

The polymer thin film M having the cylindrical microdomain 101 shown in FIGS. 2A and 2B has a planar shape of the microdomain 101 viewed from the normal direction of the substrate 104 (described later in detail). The width W ₀ (diameter D ₀ ) of the strip shape is controlled to be 47% or more of the interval L ₀ between the strip shapes, and preferably 50% or more.
That is, the polymer thin film M having the spherical microdomain 101 is configured to satisfy the relational expression of 100 · W ₀ / L ₀ ≧ 47, preferably 100 · W ₀ / L ₀ ≧ 50.

  In addition, the polymer thin film M according to the embodiment of the present invention includes a first segment, which will be described later, of the polymer block copolymer that forms the continuous phase 102 in the polymer layer made of the polymer block copolymer on the substrate 104. The volume percentage (%) of A1 (see FIG. 4) is the shape of the microdomain 101 formed by the second segment A2 (see FIG. 4) described later (for example, the spherical shape shown in FIG. 1A), or FIG. The cylinder is controlled so as to be in a predetermined range described later.

(Manufacturing method of polymer thin film)
Next, a method for producing the polymer thin film M will be described.
FIG. 3A is a schematic cross-sectional view of a state in which a block copolymer is applied to a substrate in producing the polymer thin film according to the present invention, and FIG. 3B is a block weight diagram of FIG. It is a cross-sectional schematic diagram which shows the state which carried out the micro phase separation of the coalesced coating film (polymer layer), and formed the regular structure.

As shown in FIG. 3A, in the method for manufacturing the polymer thin film M according to this embodiment, first, a coating film 202 of a polymer block copolymer to be described later is formed on the substrate 104. The coating film 202 corresponds to the “polymer layer” in the claims, and the step of forming the coating film 202 corresponds to the “first step” in the claims.
In the method of manufacturing the polymer thin film M according to this embodiment, it is desirable to use the substrate 104 having the patterned chemical modification layer 401 (see FIG. 5F), which will be described in detail later. .

  The coating film 202 is formed by dissolving a polymer block copolymer, which will be described later, in a solvent to prepare a dilute polymer block copolymer solution, which is then applied to the substrate 104 by a method such as spin coating or dip coating. What is necessary is just to apply | coat to the surface of. For example, when the spin coating method is used, the coating film 202 having a dry film thickness of about several tens of nanometers can be stably formed by setting the concentration of the solution to about several mass% and the rotation speed to 1000 to 5000 revolutions per minute. Can get to.

  The coating film 202 made of the polymer block copolymer has a structure in which the microphase separation of the polymer block copolymer does not proceed sufficiently due to the rapid vaporization of the solvent during the film formation, and the structure is non-equilibrium. In many cases, it is in a state of being completely or in a disordered state. Although the structure depends on the film forming method, it is usually not an equilibrium structure.

  Therefore, the coating film 202 is annealed in order to sufficiently advance the microphase separation process of the polymer block copolymer and obtain an equilibrium structure. As the annealing, for example, a thermal annealing method is applied in which the coating film 202 is heated to the glass transition temperature (Tg) or higher of the polymer block copolymer. In this embodiment using a polymer block copolymer described later, a thermal annealing method in which heating is performed at a temperature of 170 to 230 ° C. for several hours to several days in a vacuum atmosphere can be employed. Alternatively, a solvent annealing method using a solvent as a plasticizer may be applied.

  And in this manufacturing method, as shown in FIG.3 (b), the continuous phase 102 and the micro domain 101 are formed by carrying out the micro phase separation of the coating film 202 (polymer layer) on the board | substrate 104. FIG. That is, a plurality of spherical microdomains 101 having a second segment A2 (see FIG. 4) as components and a continuous phase 102 having a first segment A1 (see FIG. 4) as a component in a polymer block copolymer described later. Is formed. The polymer thin film M is obtained by arranging the microdomains 101 in the continuous phase 102 so as to be regularly arranged along the surface direction of the substrate 104. This step corresponds to the “second step” in the claims. Incidentally, FIGS. 3A and 3B and FIG. 4 are described assuming a manufacturing method of the polymer thin film M having the spherical microdomain 101 (see FIG. 1A). As will be described later, a polymer thin film M having a cylindrical microdomain 101 (see FIG. 2A) can also be produced depending on the polymer block copolymer to be selected.

  1, 2, and 3, the continuous phase 102, that is, the first segment of the polymer block copolymer is illustrated as constituting the outermost surface of the polymer thin film M and in contact with the substrate 104. . However, depending on the surface tension of the first segment A1 and the second segment A2 and the wettability relationship with the substrate, the surface of the polymer thin film M and the interface contacting the substrate 104, or both, In some cases, a wet phase composed of the segment A2 is formed. The case where the polymer thin film M has such a configuration is also included in the scope of the present invention.

(High molecular block copolymer)
FIG. 4 to be referred to next shows the state of the first segment and the second segment in the polymer block copolymer used for forming the polymer thin film of the present invention, and the case where the second segment forms a spherical microdomain. It is a conceptual diagram which shows as an example.
As shown in FIG. 4, the polymer block copolymer in the present embodiment includes a first segment A1 that is a component that forms the continuous phase 102 and a second segment A2 that is a component that forms the microdomain 101. Have.

In the case of forming such a spherical microdomain, the continuous phase 102 is formed among the polymer block copolymers occupied in the polymer layer on the substrate 104 (see FIG. 1A). The volume percentage of the first segment A1 is 70% to 75%.
The polymer block copolymer whose volume ratio is controlled in this way will be described in detail later. Incidentally, the boundary between the continuous phase 102 and the microdomain 101 is determined in the vicinity of the joint between the first segment A1 and the second segment A2. Therefore, the polymer block copolymer preferably has a narrow molecular weight distribution, and more preferably a polymer block copolymer synthesized by a living anionic polymerization method.

The polymer block copolymer for forming the spherical microdomain 101 in the continuous phase 102 is preferably set so that the volume of the second segment A2 is smaller than the volume of the first segment A1. .
The volume percentage (70% to 75%) of the first segment A1 forming the continuous phase 102 can be set within the range by adjusting the degree of polymerization of the first segment A1 and the second segment A2. it can. And in a polymer block copolymer, the boundary of the joint part of 1st segment A1 and 2nd segment A2 becomes easy to take a spherical shape. As a result, microphase separation is performed in which the region of the continuous phase 102 composed of the first segment A1 and the region of the spherical microdomain 101 composed of the second segment A2 are formed.
Incidentally, the size (for example, spherical diameter) of the microdomain 101 is determined according to the molecular weight of the polymer block copolymer.

  The polymer block copolymer used in the present embodiment as described above includes a cage-type silsesquioxane (polyhedral oligomeric silsesquioxane, hereinafter referred to as “POSS”) in the first segment A1. May be abbreviated as). Specific examples thereof include those containing a unit represented by the following formula (1).

(In the formula (1), R ¹ is a hydrogen atom, an alkyl group, or an aryl group; L is a POSS linker; a divalent alkyl group; a divalent aryl group; (Ester group or divalent amide group)

  Such a polymer block copolymer used in this embodiment includes a unit represented by the formula (1) as a repeating unit, and a divalent hydrocarbon in a repeating direction (in the main chain) as described later. It may further contain a group such as a divalent alkyl group. As will be described later, polymethacrylate (hereinafter simply referred to as “POSS-containing PMA”) as a polymer chain having a POSS-containing functional group in the side chain is particularly desirable.

  The POSS is a cage-type monovalent group, and examples thereof include those represented by the following formulas (a) to (e).

(In the above formulas, R is a methyl group, an ethyl group, an isobutyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, or an isooctyl group, and each R in the formulas may be the same or different. Good)

Among them, a polymer block copolymer having POSS is preferably polymethyl methacrylate-block-poly-3- (3,5,7,9,11,13,15-heptaisobutyl-pentacyclo [9.5.1 ^{3, 9} .1 ^5,15 .1 ^7,13 ] octasiloxane-1-yl) propyl methacrylate (hereinafter sometimes abbreviated as PMMA-b-PMAPOSS), polystyrene-block-poly 3- (3,5,7 , 9,11,13,15- hepta isobutyl - pentacyclo [9.5.1 ^3,9 .1 ^5,15 .1 ^7,13] octasiloxane-1-yl) propyl methacrylate (hereinafter abbreviated as PS-b-PMAPOSS to it there is), and polyethylene - block - poly 3 (3,5,7,9,11,13,15- hepta isobutyl - pentacyclo [9.5.1 ^3,9 .1 ^5,15 .1 ^7,13 ] Octasiloxane-1-yl) propyl methacrylate (hereinafter abbreviated as PEO-b-PMAPOSS) It is there). However, the polymer block copolymer that can be used in the present invention is not limited to this, and as described above, one of the first segment A1 and the second segment A2 contains POSS. In addition, any material can be used as long as it can form the microphase separation structure.
Among these, PMMA-block-PMAPOSS represented by the following formula (2) is one of desirable polymer block copolymers.

(In the formula (2), R is a methyl group, an ethyl group, an isobutyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, or an isooctyl group, and each R in the formula may be the same or different. Well, n is an integer from 1 to 200, and m is an integer from 1 to 50)

  The polymer block copolymer may be synthesized by an appropriate method, but in order to improve the regularity of the microphase separation, a synthesis method having a molecular weight distribution as narrow as possible is preferable. As described above, as an applicable synthesis method, a living anion polymerization method may be mentioned. It is also possible to adjust the volume percentage to a desired value by blending the polymer block copolymer with a homopolymer consisting only of polymer chains having the same composition as each segment constituting the polymer block copolymer. it can. Even in that case, it is desirable to use a homopolymer having a narrow molecular weight distribution used for blending.

  As such a polymer block copolymer, an AB type polymer diblock copolymer in which the ends of the first segment A1 and the second segment A2 are bonded to each other is assumed. Further, both ends of the AB type polymer diblock copolymer can be sealed with, for example, a hydrogen atom or a lower alkyl group (for example, a methyl group).

The polymer block copolymer that undergoes microphase separation so as to form the spherical microdomain 101 as described above is, as described above, the volume percentage of the first segment A1 (POSS-containing segment) that forms the continuous phase 102. Is 70% to 75%.
On the other hand, the polymer block copolymer that microphase-separates so as to form the cylindrical microdomain 101 has a volume percentage of the first segment A1 (POSS-containing segment) that forms the continuous phase 102 of 53% or more. 63%.
The size of the cylinder-shaped microdomain 101 (for example, the width W ₀ (cylinder-shaped diameter D ₀ ) shown in FIG. 2B) is determined according to the molecular weight of the polymer block copolymer. Is done.

(Chemically modified substrate)
Next, the substrate 104 used for microphase separation of the polymer block copolymer will be described. FIGS. 5A to 5F are explanatory views of a process of forming a patterned chemically modified layer on the surface of a substrate used for forming the polymer thin film of the present invention.

As described above, the substrate 104 (see FIG. 1A) in the present embodiment has the chemically modified layer 401 (see FIG. 5F) patterned.
The substrate 104 in this embodiment is assumed to be made of silicon (Si), but the material of the substrate 104 is a microstructure 60, 60a (see FIGS. 7B and 7D) described later. ), For example, inorganic materials such as glass and titania, semiconductors such as GaAs, metals such as copper, tantalum, and titanium, and organic materials (synthetic resins) such as epoxy resins and polyimides.
Note that the substrate 104 may have a hard mask layer on a surface thereof. As this hard mask layer, for example, a layer made of carbon, carbon nitride, silicon, silicon oxide, or the like, or a layer in which these layers are stacked can be cited.

  As a method for forming the chemically modified layer 401, for example, a functional group that is a starting point for the start of polymerization of the polymer block copolymer is first introduced into the surface of the substrate 104 by a coupling method or the like. And a method of synthesizing a polymer having a functional group chemically coupled to the surface of the substrate 104 in the terminal or main chain, and then coupling to the surface of the substrate 104. . In particular, the latter method is simple and recommended.

Here, a method for coupling the polystyrene to the surface of the substrate 104 to form the chemically modified layer 401 made of a polystyrene graft film will be described.
First, although illustration is omitted, polystyrene having a hydroxyl group at the terminal is synthesized by a predetermined living polymerization. Next, the density of the hydroxyl groups of the natural oxide film formed on the surface of the substrate 104 is increased by exposing the substrate 104 to oxygen plasma or immersing the substrate 104 in a piranha solution. Then, an organic solvent solution such as polystyrene toluene having a hydroxyl group at the terminal is applied onto the substrate 104 to form a film. Thereafter, the substrate 104 is heated at a temperature of about 140 ° C. for about 72 hours in a vacuum atmosphere using a vacuum oven or the like. By this treatment, the hydroxyl group on the surface of the substrate 104 and the hydroxyl group at the end of the polystyrene undergo dehydration condensation, so that the polystyrene near the surface of the substrate 104 is bonded to the substrate 104.

As a result, as shown in FIG. 5A, a chemically modified layer 401 made of a polystyrene graft film is formed on the substrate 104.
In the case of grafting polystyrene onto the surface of the substrate 104, the molecular weight of the polystyrene to be grafted is not particularly limited, but is preferably about 1,000 to 10,000 in terms of number average molecular weight. Polystyrene having a number average molecular weight within such a range can control the thickness of the polystyrene graft film to a suitable level of several nm.

Next, the chemical modification layer 401 (polystyrene graft film) provided on the surface of the substrate 104 is patterned. As will be described in detail later, the patterning is a chemical process corresponding to the arrangement of the microdomains 101 (see FIGS. 1A and 2A) distributed in the continuous phase 102 of the polymer thin film M. The chemically modified layer 401 (polystyrene graft film) means that a pattern portion having different chemical properties is formed.
As a patterning method, a known patterning technique such as photolithography or an electron beam (EB) drawing method may be applied according to a desired pattern size.

  Here, as an example of a patterning method using photolithography, as shown in FIG. 5B, a resist film 402 is formed on the surface of the chemically modified layer 401 (polystyrene graft film).

  Next, as shown in FIG. 5C, the resist film 402 is patterned by exposure, and further subjected to development processing, whereby the resist film 402 is formed into a pattern mask as shown in FIG. 5D. Is done.

  Then, as shown in FIG. 5E, the chemically modified layer 401 is etched by a method such as oxygen plasma treatment through a resist film 402 that is formed into a pattern mask. Finally, by removing the resist film 402 on the remaining chemically modified layer 401, a chemically modified layer 401 made of a patterned polystyrene graft film is obtained as shown in FIG. 5 (f). .

  That is, as shown in FIG. 5F, the substrate 104 is divided into a first region 106 made of a chemically modified layer 401 (polystyrene graft film) and a second region 107 made of an exposed surface 104a of the substrate 104. It is done. In other words, the first region 106 and the second region 107 are formed so as to have different chemical properties.

In this embodiment, the wettability of the component of the second segment A2 (see FIG. 4) of the polymer block copolymer, which is the material for forming the polymer thin film M (see FIG. 1A), to the second region 107 is high. The first region 106 is formed to be better.
As a result, the microdomain 101 formed by the second segment A2 (see FIG. 4) is arranged in the second region 107, and the other first region 106 is formed by the first segment A1 (see FIG. 4). The continuous phase 102 is disposed.
That is, according to the target (preset) interval L ₀ between the microdomains 101 shown in FIG. 1B and the degree of polymerization of the first segment A1 and the second segment A2 of the polymer block copolymer, The second region 107 is arranged so as to have a hexagonal close-packed structure. Then, the polymer block copolymer that forms the spherical microdomain 101 having the diameter D ₀ that satisfies the relational expression 100 · D ₀ / L ₀ ≧ 53 is microphase-separated on the substrate 104. Thus, the polymer thin film M according to this embodiment can be manufactured.

Moreover, when manufacturing the polymer thin film M (refer FIG. 1A) which has the micro domain 101 of a cylinder shape, the space | interval of the micro domains 101 shown in FIG. In accordance with L ₀ (strip-shaped width W ₀ ) and the degree of polymerization of the first segment A1 and the second segment A2 of the polymer block copolymer, the second region 107 is striped with the first region 106 in between. Arrange so that Then, the polymer block copolymer that forms the cylindrical microdomain 101 having a width W ₀ (diameter D ₀ ) that satisfies the relational expression 100 · W ₀ / L ₀ ≧ 47 is formed on the substrate 104. The polymer thin film M according to this embodiment can be manufactured by microphase separation.

Incidentally, the array period of the second segment A2 (see FIG. 4) of the components of the wettability good second region 107 (interval) is set to be a natural number multiple of the spacing L ₀ of the micro domains 101 together .

The patterned chemical modification layer 401 used in the method for producing the polymer thin film M of the present invention is not limited to this.
FIGS. 6A to 6C are schematic cross-sectional views showing an embodiment of a patterned chemically modified layer disposed on a substrate.

  As illustrated in FIG. 6B, the chemical modification layer 401 is patterned by being embedded in a plurality so as to be exposed on the surface of the substrate 104. That is, the chemical modification layer 401 is discretely arranged so as to form regions having different chemical properties with respect to the exposed surface of the substrate 104, thereby forming the “pattern portion” as defined in the claims. Yes. Incidentally, as a method of forming the chemically modified layer 401, for example, a method of forming a recess having a predetermined pattern by applying a lithography method or the like to the substrate 104, and filling and arranging the chemically modified layer 401 in the recess. Can be adopted.

As shown in FIG. 6C, two types of chemically modified layers 401 and 403 having different chemical properties are arranged in a pattern on the surface of the substrate 104.
Incidentally, as a method of forming the chemically modified layers 401 and 403, for example, the chemically modified layer 401 is formed on the surface of the substrate 104 in the same manner as the method of forming the chemically modified layer 401 shown in FIGS. 401 can be formed, and then a method in which the chemically modified layer 403 is disposed between the chemically modified layers 401 so as to fill the exposed surface of the substrate 104 can be employed.

  The present invention is not limited to the chemical control method using the chemically modified layers 401 and 403 as described above. For example, a steric control method (graphoepitaxy) can also be used. Incidentally, although this three-dimensional control method (graphoepitaxy) is not shown, a recess (for example, a groove, a hole, etc.) is formed on the surface of the substrate 102, and the polymer block co-polymerization according to the present embodiment is formed in the recess. The coalescence is filled to develop microphase separation. As a result, the developed microdomains are arranged along the wall surface of the recess, the directionality of the regular structure of the microdomains is controlled, and the occurrence of defects is suppressed.

(Microstructure and manufacturing method thereof)
Next, a fine structure obtained using the polymer thin film M will be described. FIGS. 7A to 7D referred to here are process diagrams for explaining a manufacturing method of a fine structure obtained by using the polymer thin film in the present embodiment. In FIGS. 7A to 7D, the description of the patterned surface of the substrate 104 is omitted. In the following description, the fine structure refers to a surface on which an uneven surface corresponding to a regular arrangement pattern of a microphase separation structure is formed.

  In this manufacturing method, as shown in FIG. 7A, a polymer thin film M having a microphase separation structure including a continuous phase 102 and a spherical microdomain 101 is prepared. Reference numeral 104 denotes a substrate.

Next, in this manufacturing method, as shown in FIG. 7B, by removing the micro domains 101 (see FIG. 7A), the substrate 104 and the plurality of micro holes H are regularly arranged. A microstructure 60 including the porous thin film 31 thus obtained is obtained.
Here, it is sufficient that either the continuous phase 102 or the microdomain 101 (see FIG. 7A) is removed. Although not shown, the fine structure 60 is formed by removing the continuous phase 102 from the microphase separation structure. By doing so, a plurality of cylinder shapes may be regularly arranged.

  As a method for removing either the continuous phase 102 of the polymer thin film M or the cylindrical micro domain 101 (see FIG. 2A), the continuous phase 102 can be obtained by reactive ion etching (RIE) or other etching methods. And a method using the difference in etching rate between the microdomain 101 and the microdomain 101.

  In addition, it is possible to improve etching selectivity by doping one of the continuous phase 102 and the microdomain 101 with a metal atom or the like.

Further, after removing either one of the continuous phase 102 and the microdomain 101, the microstructure 60 is formed by etching the substrate 104 using either the remaining continuous phase 102 or the microdomain 101 as a mask. It may be obtained.
That is, like the continuous phase 102 shown in FIG. 7B, the substrate 104 is etched by RIE or plasma etching using the remaining polymer layer (porous thin film 31) as a mask. As a result, as shown in FIG. 7C, the surface portion of the substrate 104 corresponding to the portion of the polymer layer (porous thin film 31) removed through the fine holes H is processed, and the pattern of the micro separation structure is obtained. Is transferred to the surface of the substrate 104.

Then, when the porous thin film 31 remaining on the surface of the microstructure 60 is removed by RIE or a solvent, as shown in FIG. 7D, it corresponds to the spherical micro domain 101 (see FIG. 7A). The fine structure 60a is obtained as the substrate 104 on which the fine holes H having the pattern are formed.
That is, the present invention may be a fine structure 60 composed of the substrate 104 and the porous thin film 31, or may be a fine structure 60a composed of the substrate 104 itself in which the fine holes H are formed.
7A to 7D, the structure in which the polymer thin film M is formed directly on the surface of the substrate 104 has been described. However, the present invention is not limited to the surface of the substrate 104. After forming the above-described hard mask layer (not shown), a method for manufacturing a fine structure in which the polymer thin film M is formed through the hard mask layer can also be used.

The fine structures 60 and 60a obtained by the manufacturing method described above are applied to various applications because the uneven surface of the pattern formed on the surface is fine and the aspect ratio is large.
For example, the surface of the manufactured fine structures 60, 60a is repeatedly brought into close contact with the transfer target by a nanoimprint method or the like, so that a large number of replicas of the fine structures 60, 60a having the same regular arrangement pattern on the surface. It can be used for applications such as manufacturing.

Next, a method for transferring a fine pattern on the concavo-convex surface of the fine structures 60, 60a (hereinafter, simply referred to as “fine structure” by a nanoimprint method) to a predetermined transfer target will be described.
The first method is a method of imprinting a manufactured microstructure directly on a transfer target to transfer a regular array pattern (this method is called a thermal imprint method). This method is suitable when the material to be transferred is a material that can be directly imprinted. For example, when a thermoplastic resin typified by polystyrene is used as a transfer object, after the thermoplastic resin is heated to a temperature higher than the glass transition temperature, the fine structure is pressed against the transfer object to be in close contact with the glass transition temperature or lower. A replica can be obtained by releasing the fine structure from the surface of the transfer object after cooling to the minimum.

  Further, as a second method, when the fine structure is a light transmissive material such as glass, a photocurable resin is applied as a transfer target (not shown) (this method is a photoimprint method). Called). When light is irradiated after the photo-curable resin is brought into close contact with the fine structure, the photo-curable resin is cured. Therefore, the fine structure is released, and the photo-curable resin (cured material) after curing is released. Can be used as a replica.

  Further, in such an optical imprint method, for example, when a glass substrate is used as a transfer target (not shown), a photocurable resin is interposed in a gap between the fine structure and the glass substrate. Adhere to it and irradiate it with light. Then, after the photocurable resin is cured, the fine structure is released, and the cured photocurable resin having irregularities on the surface is used as a mask, and a regular arrangement pattern is formed on the glass substrate by plasma or ion beam. There is also a transfer method in which the etching process is performed.

According to the embodiment of the present invention as described above, according to the shape (for example, spherical shape, cylinder shape, etc.) of the microdomain 101 formed by the second segment A2 in the volume occupied by the polymer block copolymer. The volume percentage of the first segment A1 of the polymer block copolymer forming the continuous phase 102 is controlled to be within a predetermined range. That is, the polymer thin film M having the spherical microdomain 101 has a volume percentage of the first segment A1 of 70% to 75%, and the polymer thin film M having the cylindrical microdomain 101 has the first segment A1. The volume percentage is 53% to 63%.
In the present invention, the size of the microdomain 101 is increased by adopting such a configuration.

On the other hand, in the conventional polymer films that microphase separation, too small a diameter D ₀ of the micro domains for microdomains distance L _0, where it has been difficult to etching the substrate with high precision, whereas In the present invention, since the size of the microdomain 101 can be increased by the above-described configuration, the substrate 104 can be etched with high accuracy.

  Incidentally, in a conventional polymer thin film, for example, a polystyrene-block-polymethylmethacrylate copolymer (PS-b-PMMA) thin film, a polymer block chain made of polystyrene (corresponding to the first segment forming a continuous phase). When the volume percentage is about 87% or less, the micro domain cannot maintain the spherical shape, and the micro phase separation structure is changed from the spherical shape to the cylindrical shape. According to this embodiment, the volume of the first segment A1 is changed. Even when the percentage is about 70%, the microdomain 101 can sufficiently maintain the spherical shape.

In addition, in the conventional polymer thin film, when the volume percentage of the polymer block chain made of polystyrene (corresponding to the first segment forming the continuous phase) is about 67% or less, the microdomain cannot maintain the cylinder shape, When the microphase separation structure is changed from the cylinder shape to the lamellar shape, according to the present embodiment, the microdomain 101 sufficiently maintains the cylinder shape even if the volume percentage of the first segment A1 is about 53%. Can do.
That is, according to the present embodiment, the change point (change region) of the microphase separation structure is shifted as compared with the conventional polymer thin film, so that the microdomain 101 has a distance L ₀ between the microdomains 101. it can be said that it is possible to increase than the conventional diameter D _0.

Further, according to the embodiment of the present invention, since the diameter D ₀ of the microdomain 101 is equal to or larger than the predetermined ratio of the interval L ₀ between the microdomains 101, the substrate 104 can be more reliably and accurately provided. It can be etched.

  The fine structure of the present invention exemplified by the polymer thin film M, the fine structure, and replicas thereof has a structure with excellent regularity over a wide range and few defects. It can be applied to an information recording medium such as a medium. In addition, such a microstructure of the present invention includes large-scale integrated circuit components, optical components such as lenses, polarizing plates, wavelength filters, light-emitting elements, and optical integrated circuits, bioanalyses such as immunoassay, DNA separation, and cell culture. It can be applied to devices.

Next, the effects of the present invention will be described more specifically with reference to examples of the present invention.
Example 1
In Example 1, a polymer block copolymer for forming a polymer thin film was first prepared. Specifically, it is a polymer block copolymer represented by the following structural formula (2).

(However, in said Formula (2), R is an ethyl group, m is 42, and n is 16.)

This polymer block copolymer includes polymethacrylate (PMAPOSS: first segment A1 (see FIG. 4)) having a side chain composed of a silsesquioxane skeleton, and polymethyl methacrylate known as a general hydrocarbon polymer. It is a diblock copolymer in which (PMMA: second segment A2 (see FIG. 4)) is combined. The number average molecular weight Mn of this polymer block copolymer is 16,200, and the volume ratio of PMAPOSS to the volume occupied by the polymer block copolymer is 74%.
Further, this polymer block copolymer had a polydispersity index Mw / Mn of the molecular weight distribution as a whole of 1.04.
Hereinafter, the polymer block copolymer in Example 1 is sometimes referred to as “first polymer block copolymer”.

<Preparation of polymer thin film>
A coating film of a polymer block copolymer was formed on a silicon substrate. And the polymer thin film of this invention was obtained by carrying out micro phase separation of the coating film of a polymer block copolymer. This microphase separation process was performed by performing thermal annealing at 180 ° C. for 24 hours.

  Next, the microphase separation structure of the polymer thin film was observed with a scanning electron microscope (SEM manufactured by Hitachi High-Technologies Corporation, model S4800). SEM observation was performed under the condition of an acceleration voltage of 1.5 kV. In order to accurately measure the fine structure, the necessary contrast was obtained by adjusting the acceleration voltage without performing deposition of Pt or the like on the surface of the sample, which is usually performed for the prevention of charging in SEM observation.

The polymer thin film in the present example is a spherical microdomain (microcircular or dot-shaped in a plan view) made of PMMA (second segment A2 (see FIG. 4)) and PMAPOSS (first segment). It was microphase-separated into a continuous phase consisting of A1 (see FIG. 4).
Then, the ratio _{(100 · D 0 / L 0} ) of the diameter _{D 0} of the micro domains with respect to distance _{L 0} microdomains each other, was 54%.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner. The SEM observation result at this time is shown in FIG.

<Fabrication of microstructure>
Using the prepared polymer thin film (micro phase separation structure) as a mask (resist), the substrate was etched. Here, the fine structure 60a was manufactured in the same manner as the manufacturing process shown in FIGS.
First, by performing reactive ion etching (RIE) on the polymer thin film M shown in FIG. 7A, a part of the upper layer of the polymer thin film M is removed to such an extent that the upper half of the spherical microdomain 101 is removed. Removed.

Thus, the polymer thin film M in which the micro-domains 101 having a microcircular shape were exposed in the sea phase in the continuous phase 102 was obtained. CF ₄ gas is used for this reactive ion etching. However, reactive ion etching is not limited to this CF ₄ gas, and other CHF ₃ gas or the like can be used if the PMAPOSS layer (continuous phase 102) can be removed. You can also.

Next, the microdomain 101 made of PMMA (second segment A2 (see FIG. 4)) exposed to the continuous phase 102 is removed by reactive ion etching of O ₂ gas. At this time, the continuous phase 102 made of PMAPOSS (first segment A1 (see FIG. 4)) is more resistant to etching against O ₂ gas than the microdomain 101 made of PMMA (second segment A2 (see FIG. 4)). 7B, the microdomain 101 is selectively removed, and the microstructure includes the substrate 104 and the porous thin film 31 in which a plurality of micropores H are regularly arranged. A body 60 was obtained.
For reactive ion etching that selectively removes the microdomains 101, it is desirable to use O ₂ gas, but other gases can be used as long as PMMA (microdomains 101) can be selectively removed.

Next, reactive ion etching using CF ₄ gas was performed on the porous thin film 31 having the fine holes H shown in FIG. 7B to expose the substrate 104 at positions corresponding to the fine holes H. Thereby, a mask (not shown) using the microphase separation structure as a template can be formed.

Then, the substrate 104 having the patterned mask is subjected to reactive ion etching using HBr gas or Cl ₂ gas, and as shown in FIG. Micropores H were formed.

Then, as shown in FIG. 7D, the residue of the polymer thin film M (porous thin film 31) remaining on the substrate 104 is removed by O ₂ ashing, so that the micro domain 101 (FIG. A microstructure 60a to which the pattern of a) was transferred was obtained.

  Incidentally, a hard mask is inserted between the substrate 104 and the self-assembled film (polymer thin film M) for the purpose of improving the aspect ratio of the fine holes H (see FIG. 7C) formed in the substrate 104. You can also. Such a hard mask is preferably made of a material having a high etching selectivity with respect to the substrate 104, and examples thereof include those made of SiN, SiO, C, and the like.

  Then, as a result of observing the surface of the fine structure 60a manufactured in this example with an SEM, the fine structure 60a is formed by periodically arranging the fine holes H substantially free of connection or defects of the fine holes H. I was able to confirm. The SEM image is shown in FIG.

In the following Table 1, the type of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 1), the natural period d ₀ (nm of the microdomain) ), The diameter of the microdomain (indicated as “dot diameter” in Table 1), and the pattern transfer result.
In addition, regarding the “pattern transfer result” in Table 1, the surface of the obtained fine structure 60a is substantially free from connection or defect of the fine holes H, and the fine holes H on the surface are periodically arranged. Was evaluated as “◯”, and those in which the connection and defects of the fine holes H were observed on the surface, or those in which the fine holes H were not periodically arranged were evaluated as “x”.

(Comparative Example 1)
In Comparative Example 1, the volume represented by the formula (2), where R is an ethyl group, m is 22, n is 18, number average molecular weight Mn is 15,800, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 86% and a polydispersity index Mw / Mn of 1.06 (hereinafter sometimes referred to as “fourth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.
And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner.

The ratio _{(100 · D 0 / L 0} ) of the diameter _{D 0} of the micro domains with respect to distance _{L 0} microdomains each other, was 48%.

The SEM observation result at this time is shown in FIG. Moreover, the surface of the fine structure 60a produced in the comparative example 1 was observed with an SEM (FIG. 8D). As a result, the connection of the fine holes H and defects were observed in the fine structure 60a.
Table 1 shows the types of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 1), the natural period d ₀ (nm) of the microdomain, The diameter (denoted as “dot diameter” in Table 1) and the pattern transfer result are described.

(Example 2)
In Example 2, the volume represented by the formula (2), where R is an ethyl group, m is 51, n is 16, number average molecular weight Mn is 17,000, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 70% and a polydispersity index Mw / Mn of 1.05 (hereinafter, this may be referred to as “second polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.

And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner.

The ratio _{(100 · D 0 / L 0} ) of the diameter _{D 0} of the micro domains with respect to distance _{L 0} microdomains each other, was 55%.
Further, the surface of the fine structure 60a produced in Example 2 was observed with an SEM. As a result, it was confirmed that the fine structure 60a was formed by periodically arranging the fine holes H substantially without any connection or defect of the fine holes H.

Table 1 shows the types of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 1), the natural period d ₀ (nm) of the microdomain, The diameter (denoted as “dot diameter” in Table 1) and the pattern transfer result are described.

(Example 3)
In Example 3, the volume represented by the formula (2), where R is an ethyl group, m is 40, n is 16, number average molecular weight Mn is 15,900, and PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 75% and a polydispersity index Mw / Mn of 1.04 (hereinafter sometimes referred to as “third polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.

And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner.

The ratio _{(100 · D 0 / L 0} ) of the diameter _{D 0} of the micro domains with respect to distance _{L 0} microdomains each other, was 53%.
Further, the surface of the fine structure 60a produced in Example 3 was observed with an SEM. As a result, it was confirmed that the fine structure 60a was formed by periodically arranging the fine holes H substantially without any connection or defect of the fine holes H.

Table 1 shows the types of polymer block copolymers used for the study, the volume percentage of the first segment A1 (indicated as “PMAPOSS volume fraction” in Table 1), and the natural period d ₀ (nm). The distance L ₀ and the diameter D _{0 of} the spherical microdomains (indicated as “PMMA domain distance” and “PMMA domain diameter” in Table 1) and the pattern transfer result are described.

(Comparative Example 2)
In Comparative Example 2, the volume represented by the formula (2), where R is an ethyl group, m is 38, n is 16, number average molecular weight Mn is 15,700, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 76% and a polydispersity index Mw / Mn of 1.04 (hereinafter sometimes referred to as “fifth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.
And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner.

The ratio _{(100 · D 0 / L 0} ) of the diameter _{D 0} of the micro domains with respect to distance _{L 0} microdomains each other, was 52%.

Moreover, the surface of the fine structure 60a produced in this comparative example 2 was observed with SEM. As a result, a slight connection of the fine holes H and defects were observed in the fine structure 60a.
Table 1 shows the types of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 1), the natural period d ₀ (nm) of the microdomain, The diameter (denoted as “dot diameter” in Table 1) and the pattern transfer result are described.

(Comparative Example 3)
In Comparative Example 3, the volume represented by the formula (2), where R is an ethyl group, m is 30, n is 16, number average molecular weight Mn is 14,900, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 80% and a polydispersity index Mw / Mn of 1.07 (hereinafter sometimes referred to as “sixth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.
And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine holes (decomposed and removed portions of spherical microdomains) derived from the structure of microphase separation were arranged in the sample in a hexagonal manner.

The ratio (100 · D ₀ / L ₀ ) of the diameter D ₀ of the micro domains to the distance L ₀ between the micro domains was 51%.

Moreover, the surface of the fine structure 60a produced in this comparative example 2 was observed with SEM. As a result, the connection of the fine holes H and defects were observed in the fine structure 60a.
Table 1 shows the types of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 1), the natural period d ₀ (nm) of the microdomain, The diameter (denoted as “dot diameter” in Table 1) and the pattern transfer result are described.

Example 4
In Example 4, the volume represented by the formula (2), where R is an ethyl group, m is 62, n is 14, number average molecular weight Mn is 17,100, and PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 63% and a polydispersity index Mw / Mn of 1.04 (hereinafter sometimes referred to as “seventh polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.

And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine line structures derived from the structure of microphase separation (decomposed and removed portions of cylinder-shaped microdomains) were arranged in parallel in the sample at equal intervals. The SEM observation result at this time is shown in FIG.

The ratio (100 · W ₀ / L ₀ ) of the width W ₀ of the microdomain (strip shape) to the interval L ₀ between the microdomains was 47%.
Further, the surface of the fine structure 60a produced in Example 4 was observed with an SEM. As a result, it was confirmed that a line-and-space structure was formed on the surface of the fine structure 60a, and the repetition of line-and-space without connection and defects was periodically arranged.
The SEM observation result at this time is shown in FIG.

In the following Table 2, the kind of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “PMAPOSS volume fraction” in Table 2), the natural period d _{0 of the} microdomain (nm ), The diameter of the cylinder-shaped microdomain (referred to as “PMMA domain diameter” in Table 2), and the pattern transfer result.

  Regarding the “pattern transfer result” in Table 1, a line-and-space structure is formed on the surface of the obtained fine structure 60a, and line-and-space repetition without line connection or defect is periodically arranged. Was evaluated as “◯”, and “×” was evaluated as a case where a line connection or a defect was observed on the surface, or a case where the repetition of line and space was not periodically arranged.

(Comparative Example 4)
In Comparative Example 4, the volume represented by the formula (2), where R is an ethyl group, m is 55, n is 14, number average molecular weight Mn is 16,100, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 66% and a polydispersity index Mw / Mn of 1.06 (hereinafter sometimes referred to as “tenth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.
And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM. As a result of SEM observation, it was confirmed that nanoscale fine line structures derived from the structure of microphase separation (decomposed and removed portions of cylinder-shaped microdomains) were arranged in parallel in the sample at equal intervals. The SEM observation result at this time is shown in FIG.

The ratio (100 · W ₀ / L ₀ ) of the width W ₀ of the microdomain (strip shape) to the interval L ₀ between the microdomains was 45%.
In addition, the surface of the fine structure 60a produced in Comparative Example 4 was observed with an SEM. As a result, line connections and defects were observed on the surface of the fine structure 60a, and the fine structure 60a was not periodically arranged with repeated lines and spaces.
The SEM observation result at this time is shown in FIG.

Table 2 shows the type of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 2), the microdomain natural period d ₀ (nm), and the cylinder shape. The diameter of the microdomain (referred to as “PMMA domain diameter” in Table 2) and the pattern transfer result are shown.

(Example 5)
In Example 5, the volume represented by the formula (2), where R is an ethyl group, m is 82, n is 13, number average molecular weight Mn is 18,700, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 56% and a polydispersity index Mw / Mn of 1.05 (hereinafter, this may be referred to as “eighth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.

And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine line structures derived from the structure of microphase separation (decomposed and removed portions of cylinder-shaped microdomains) were arranged in parallel in the sample at equal intervals.

The ratio (100 · W ₀ / L ₀ ) of the width W ₀ of the microdomain (strip shape) to the interval L ₀ between the microdomains was 49%.
Further, the surface of the fine structure 60a produced in Example 5 was observed with an SEM. As a result, it was confirmed that a line-and-space structure was formed on the surface of the fine structure 60a, and the repetition of line-and-space without connection and defects was periodically arranged.

Table 2 shows the type of the polymer block copolymer, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 2), the microdomain natural period d ₀ (nm), and the cylinder shape. The diameter of the microdomain (referred to as “PMMA domain diameter” in Table 2) and the pattern transfer result are shown.

(Example 6)
In Example 6, the volume represented by the formula (2), where R is an ethyl group, m is 93, n is 14, number average molecular weight Mn is 19,700, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 53% and a polydispersity index Mw / Mn of 1.04 (hereinafter, this may be referred to as “the ninth polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.

And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM.
As a result of SEM observation, it was confirmed that nanoscale fine line structures derived from the structure of microphase separation (decomposed and removed portions of cylinder-shaped microdomains) were arranged in parallel in the sample at equal intervals.

The ratio (100 · W ₀ / L ₀ ) of the width W ₀ of the microdomain (strip shape) to the interval L ₀ between the microdomains was 50%.
Further, the surface of the fine structure 60a produced in Example 6 was observed with an SEM. As a result, it was confirmed that a line-and-space structure was formed on the surface of the fine structure 60a, and the repetition of line-and-space without connection and defects was periodically arranged.

In Table 2, the type of the polymer block copolymer used for the study, the volume percentage of the first segment A1 (indicated as “volume fraction of PMAPOSS” in Table 2), natural period d ₀ (nm), The spacing L ₀ and the diameter D ₀ (referred to as “PMMA domain spacing” and “PMMA domain diameter” in Table 2) and the pattern transfer result are shown.

(Comparative Example 5)
In Comparative Example 5, the volume represented by the formula (2), where R is an ethyl group, m is 59, n is 14, number average molecular weight Mn is 16,300, PMAPOSS (first segment A1 (see FIG. 4)). Using a polymer block copolymer having a ratio of 66% and a polydispersity index Mw / Mn of 1.04 (hereinafter, this may be referred to as “11th polymer block copolymer”), In the same manner as in Example 1, the polymer thin film M and the fine structure 60a were produced.
And similarly to Example 1, the surface of the polymer thin film M and the surface of the fine structure 60a were observed with SEM. As a result of SEM observation, it was confirmed that nanoscale fine line structures derived from the structure of microphase separation (decomposed and removed portions of cylinder-shaped microdomains) were arranged in parallel in the sample at equal intervals.

The ratio (100 · W ₀ / L ₀ ) of the width W ₀ of the microdomain (strip shape) to the interval L ₀ between the microdomains was 46%.
In addition, the surface of the fine structure 60a produced in Comparative Example 5 was observed with an SEM. As a result, line connections and defects were observed on the surface of the fine structure 60a, and the fine structure 60a was not periodically arranged with repeated lines and spaces.

(Comparative Example 6)
In Comparative Example 6, the polymer thin film M was formed using PS-b-PMMA in which the first segment A1 is polystyrene (PS) and the second segment A2 is polymethyl methacrylate (PMMA) as the polymer block copolymer. . As PS-b-PMMA, PS _340- b-PMMA ₁₂₂ (Mn is 47,700, Mw / Mn is 1.04) having a volume fraction of polystyrene of 74% and PS _232- b-PMMA having 55% is used. ₂₀₀ (Mn 44,000, Mw / Mn 1.07) was used.
A PS-b-PMMA coating film was formed on a silicon substrate. And the polymer thin film M was obtained by carrying out the micro phase separation of the coating film of a polymer block copolymer. This microphase separation process was performed by performing thermal annealing at 230 ° C. for 24 hours.
Next, the microphase separation structure of the polymer thin film M was observed by SEM. As a result, PS-b-PMMA with a volume fraction of 74% has a structure in which cylindrical microdomains are arranged at an interval L ₀ = 29 nm, and PS-b-PMMA with a volume fraction of 55% has a lamellar microdomain. It was found that a structure arranged with an interval L ₀ = 25 nm was formed.
From the above results, it became clear that PS-b-PMMA cannot obtain a spherical structure when the volume fraction of the PS phase is 74%. It was also found that a cylinder-shaped structure cannot be obtained when the volume fraction of the PS phase is 55%.

(Example 7)
In Example 7, a method of manufacturing a magnetic recording medium (bit pattern medium) using the fine structure 60a (see FIG. 7D) according to the present embodiment will be described with reference to the drawings as appropriate.
Next, FIG. 10 to be referred to is a schematic plan view schematically showing the configuration of the surface of the magnetic recording medium (fine structure) produced in Example 7. The magnetic recording medium 300 is a so-called bit pattern medium (BPM) in which each recording bit is separated.

  As shown in FIG. 10, the magnetic recording medium 300 has a disk shape with a diameter of 65 mm and a thickness of 0.631 mm, and has a structure in which a plurality of magnetic layers and other layers are deposited on a substrate 301. A hole 302 having a diameter of 20 mm for fixing the magnetic recording medium 300 to the spindle is provided at the center of the substrate 301.

The plurality of recording tracks 303 are formed concentrically around the hole 302, and are structured to be magnetically separated from adjacent tracks by a nonmagnetic material.
The outermost surface of the magnetic recording medium 300 is flattened, and the difference in height between the recording track 303 and the nonmagnetic material region is less than 5 nm.

The magnetic recording medium 300 is also formed with a servo pattern 304 for accessing a region on a desired track and performing a recording / reproducing operation.
In FIG. 10, the servo pattern 304 is schematically shown as a curve, but the servo pattern 304 is formed by incorporating a fine pattern.
Further, the servo pattern 304 in FIG. 10 is composed of twelve for convenience of drawing, but actually, it is provided so that one circumference of the magnetic recording medium 300 is divided into 200 and the servo pattern 304 enters each area. It has been. Of course, the number of servo patterns 304 is not limited to 200 and needs to be determined from the recording / reproducing characteristics.
Further, the magnetic recording medium 300 can be provided with an inner peripheral portion 306 and an outer peripheral portion 305 in which the recording track 303 and the servo pattern 304 are not formed.

Next, a method for manufacturing the magnetic recording medium 300 using the method for manufacturing a microstructure according to the present invention will be described. Note that the reference numerals in the following description correspond to the reference numerals attached to the magnetic recording medium 300 in FIG.
In this manufacturing method, first, a soft magnetic backing layer (SUL) was grown on the substrate 301.

Examples of the material of the substrate 301 include metals such as glass and aluminum, semiconductors such as silicon, insulating resins such as ceramics and polycarbonate.
The soft magnetic backing layer employs an Fe—Ta—C alloy, and was subjected to necessary heat treatment after sputter deposition in a vacuum chamber. It is desirable to give magnetic anisotropy in the radial direction of the medium to the soft magnetic backing layer.

  In addition, other soft magnetic underlayers may be used instead of the Fe—Ta—C alloy, and other growth methods other than sputter deposition may be employed. If necessary, an adhesion layer for enhancing the adhesion between the substrate 301 and the soft magnetic backing layer, an intermediate layer for controlling the crystallinity of the soft magnetic backing layer, or the like can be inserted.

  After the formation of the soft magnetic backing layer, the recording layer is formed by sputter deposition in a vacuum. In this embodiment, a Co—Cr—Pt film is employed as the recording layer. This material is characterized by having an easy axis of magnetization in a direction perpendicular to the film surface direction. Therefore, in this embodiment, the sputter deposition conditions are set so that the axis of magnetic anisotropy is substantially perpendicular to the surface of the substrate 301. The magnetic material used for the recording layer is not limited to the Co—Cr—Pt alloy, and other materials may be used. In particular, a recording layer containing Si called a granular film is compatible with the present invention. Furthermore, a protective layer was formed on the recording layer for substrate processing. A silicon nitride (SiN) film was adopted as a material for the protective layer.

  The protective layer is not limited to this SiN, and other materials may be used. A polymer thin film M was formed on the protective layer of the substrate 301 in the same manner as in Example 5. Thereafter, through the steps shown in FIGS. 7A to 7D, a fine structure 60a was obtained.

Then, a nonmagnetic material is embedded in the concave portion of the fine structure 60a as necessary. An example of this non-magnetic material is SiO ₂ . This non-magnetic material is formed by being grown from the top of the substrate 301 and then planarized by etch back or chemical mechanical polishing (CMP). Then, if necessary, a protective film and a lubricating film are formed on the substrate 301, whereby the magnetic recording medium 300 is completed.

In this embodiment, by forming the fine structure 60a on the recording layer, it is possible to manufacture a magnetic recording medium 300 (bit pattern medium) having a structure with excellent regularity over a wide range and few defects.
In this example, the recording layer was processed using the microstructure as a mask. However, the recording layer may be processed in the nanoimprint process using the microstructure transferred to the Si substrate manufactured in Example 5 as a mold. Is possible. In addition, after the fine structure 60a is formed on the substrate 301, each magnetic film can be grown on the uneven shape of the fine structure 60a.

60 fine structure 60a fine structure 101 micro domain 102 continuous phase 104 substrate 300 magnetic recording medium 301 substrate 401 chemically modified layer 402 resist film 403 chemically modified layer A1 first segment A2 second segment d ₀ natural period D ₀ micro Domain diameter L ₀ Spacing between micro domains M Polymer thin film W ₀ width

Claims (14)

A first step of disposing on a substrate a polymer layer comprising a polymer block copolymer having at least a first segment and a second segment;
A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component;
In a method for producing a polymer thin film having
The polymer block copolymer has a silsesquioxane skeleton in the first segment,
Of the volume occupied by the polymer block copolymer in the polymer layer, the volume percentage of the first segment is 53% to 63%, and the microdomains extend in parallel along the substrate. A method for producing a polymer thin film characterized by having a cylinder shape. A first step of disposing on a substrate a polymer layer comprising a polymer block copolymer having at least a first segment and a second segment;
A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component;
In a method for producing a polymer thin film having
The polymer block copolymer has a silsesquioxane skeleton in the first segment,
The polymer thin film characterized in that the volume percentage of the first segment is 70% to 75% of the volume occupied by the polymer block copolymer in the polymer layer, and the microdomain is spherical. Manufacturing method. In the manufacturing method of the polymer thin film of Claim 1,
The cylinder-shaped microdomain exhibits a plurality of strip shapes arranged in a plan view as viewed from the normal direction of the substrate, and the width of the strip shape is 47% or more of the interval between the strip shapes. A method for producing a polymer thin film. In the manufacturing method of the polymer thin film of Claim 2,
The spherical microdomain has a microcircular shape in plan view as viewed from the normal direction of the substrate, and the diameter of the microcircular shape is 53% or more of the interval between the microcircular shapes. A method for producing a polymer thin film. In the manufacturing method of the polymer thin film of Claim 1,
A method for producing a polymer thin film, wherein the interval between the cylinder-shaped microdomains is 5 to 25 nm. In the manufacturing method of the polymer thin film of Claim 2,
A method for producing a polymer thin film, wherein the space between the spherical microdomains is 5 to 25 nm. In the manufacturing method of the polymer thin film of Claim 1 or Claim 2,
In the first step, a chemically modified layer is formed on the substrate so as to correspond to the continuous phase, and a pattern having a chemical property different from that of the chemically modified layer so as to correspond to the arrangement of the microdomains. The manufacturing method of the polymer thin film characterized by having the process which has a part. In the manufacturing method of the polymer thin film of Claim 7,
The method for producing a polymer thin film characterized in that the arrangement period of the pattern portions is a natural number times the natural period of the microdomain. In the manufacturing method of the polymer thin film of Claim 8,
The difference in chemical properties of the pattern part with respect to the chemically modified layer is that the wettability of the pattern part to the component of the second segment is better than that of the chemically modified layer. Production method. A first step of disposing on a substrate a polymer layer comprising a polymer block copolymer having at least a first segment and a second segment;
A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component;
A third step of removing one of the continuous phase and the microdomain of the polymer layer;
In the manufacturing method of the fine structure having
The polymer block copolymer has a silsesquioxane skeleton in the first segment,
Of the volume occupied by the polymer block copolymer in the polymer layer, the volume percentage of the first segment is 53% to 63%, and the microdomains extend in parallel along the substrate. A manufacturing method of a fine structure characterized by having a cylinder shape. A first step of disposing on a substrate a polymer layer comprising a polymer block copolymer having at least a first segment and a second segment;
A second step of microphase-separating the polymer layer and regularly arranging a plurality of microdomains having the second segment as components in the continuous phase having the first segment as a component;
A third step of removing one of the continuous phase and the microdomain of the polymer layer;
In the manufacturing method of the fine structure having
The polymer block copolymer has a silsesquioxane skeleton in the first segment,
Of the volume occupied by the polymer block copolymer in the polymer layer, the volume percentage of the first segment is 70% to 75%, and the micro domain is spherical. Manufacturing method. In the manufacturing method of the fine structure according to claim 10 or claim 11,
After the third step of removing one of the continuous phase and the microdomain of the polymer layer, a step of etching the substrate using the other of the remaining continuous phase and the microdomain as a mask. A method for producing a fine structure, comprising:   A polymer thin film obtained by the method for producing a polymer thin film according to claim 1.   A fine structure obtained by the method for producing a fine structure according to claim 10 or 11.