JP2014078309A - Substrate, manufacturing method of substrate, recording medium, manufacturing method of recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate manufacturing method capable of forming a nano-order isolated particulate patterns with little variation in size and high positional accuracy.SOLUTION: The substrate manufacturing method includes: a concave portion forming step to form a concave portion in an organic material on a base material; an SOG applying step to apply SOG on the concave portion; a first etching process to partially expose the organic material by removing a part of the SOG; and a second etching process to form a reversely tapered protrusion of the SOG by removing exposed organic material.

Description

  The present invention relates to a recording medium, a recording medium manufacturing method, and a substrate and a substrate manufacturing method using a nanoimprint process.

  In recent years, the amount of information handled by users has increased remarkably due to dramatic improvements in information equipment such as personal computers. Information recording / reproducing devices with a significantly higher recording density and semiconductor devices with a higher degree of integration than before. Is required.

  Therefore, it is required to increase the capacity of a memory using a magnetic material typified by an HDD (Hard Disk Drive) and an optical memory such as a BD (Blu-ray disc) as a large-capacity recording medium.

First, in order to increase the capacity of the HDD, instead of the in-plane recording method in which the magnetization is recorded in the in-plane direction of the substrate, the method of recording the magnetization in the vertical direction of the substrate, which is considered strong against the problem of thermal fluctuation, the so-called vertical Recording type HDD was commercialized. In order to further increase the density, there is a problem that, as the recording bit is miniaturized, variations in the shape and size of the magnetic particles cause noise, thereby degrading the signal quality. As a solution, it is considered effective to reduce the exchange interaction between adjacent magnetic particles, to reduce the size of the magnetic particles, and to make the shape uniform. Among them, the one in which the magnetic particles are controlled and the magnetic particles having a uniform size are regularly arranged is called patterned media, and an ultra-high density recording medium having a recording density of 1 Tbit / in ² class can be realized. It is attracting attention as being possible. As a method for producing such patterned media, there is a method (Patent Document 1) in which processing such as etching is performed on the magnetic layer.

  In addition, to increase the capacity of optical memory, it is difficult to reduce the size of recording marks beyond the diffraction limit of light with the current optical recording method. However, the optical recording method using near-field light is difficult to achieve this diffraction. It is attracting a great deal of attention as a technology that breaks the limits. As one of such technologies, a near-field light generating element using metal plasmon resonance has been proposed recently (Patent Document 2). In this technique, a minute metal film is irradiated with light having an appropriate wavelength to induce surface plasmon resonance, and near-field light in the vicinity of the metal film is generated to perform recording / reproduction.

  As described above, the HDD recording / playback system and the optical memory recording / playback system are based on completely different playback principles, but there is a common point as a requirement to be satisfied by the recording medium for further improving the recording density. . The requirement is that the recording film to be formed on the recording medium is an isolated fine particle and the material is a magnetic film or a metal film, and the size of these fine particles is uniform. Since the change in state of these fine particles corresponds to one bit of information, the larger the number of fine particles arranged per unit area, that is, the smaller the fine particle size, the more data can be stored on the recording medium. Is also a common point.

  Here, the formation process of the fine particle pattern will be described.

  In recent years, a microfabrication technique for transferring a fine structure on a mold to a workpiece such as resin or metal has been developed and attracts attention. This technology is called nanoimprinting and has a resolution of the order of several nanometers. Therefore, there is an increasing expectation as a next-generation semiconductor manufacturing technology that replaces optical exposure machines such as steppers and scanners (Non-Patent Document 1).

  Specifically, a photo-curing resin layer is formed on the substrate, a mold having a desired uneven pattern formed thereon is pressed against the resin, further pressurized, and irradiated with ultraviolet light to cure the resin. Alternatively, a thermoplastic resin is formed on the substrate, the mold is pressed against the softened resin by heating the substrate, and the temperature is lowered to lower the resin. Hereinafter, the former is referred to as optical imprint, and the latter is referred to as thermal imprint.

  As a result, a pattern is formed on the resin layer. This is used as it is as a substrate, or etching is performed using this resin layer as a mask layer to form a pattern on the substrate.

Japanese Patent Laid-Open No. 9-297918 JP 2003-114184 A

Stephan y. Chou ET. Al. Appl. Phys. Lett, Vol. 67, Issue 21, pp. 3114-3116 (1995)

  In the conventional method, it has been difficult to supply a recording medium in which nano-order fine particles are regularly arranged with small size variation and high positional accuracy.

  In order to solve the above-described conventional problems, a substrate manufacturing method according to the present invention includes a recess forming step for forming a recess in an organic material on a base material, an SOG coating step for applying SOG onto the recess, and a part of the SOG. A first etching step in which the organic material is partially exposed to remove the organic material, and a second etching step in which the exposed organic material is removed to form a convex portion made of SOG having an inversely tapered shape. It is characterized by.

  The recording medium manufacturing method of the present invention is characterized in that a recording film is formed on a substrate having the reverse tapered SOG, and an isolated recording film is formed on the top of the SOG.

  The recording medium manufacturing method of the present invention is characterized in that SOG is further applied on the isolated recording film and the surface of the recording medium is smoothed by a spin coating method.

  The present invention solves the above-described conventional problems, and provides a pattern formation method that can form isolated fine particles even with the configuration of a recording film material and a recording film. To do.

  In addition, if this method is used, it is possible to supply a recording medium in which nano-order fine particles with small size variations and high positional accuracy are regularly arranged, so that recording with low noise and high recording density is possible. It becomes possible to supply a medium.

The figure which shows all the processes of this embodiment The figure which shows an example of the microparticle formation process of a comparative example The figure which shows an example of the microparticle formation process of a comparative example The figure which shows the process of Embodiment 1. The figure which shows the process of Embodiment 2. The figure which shows the process of Embodiment 3. The flowchart which shows the manufacturing method in embodiment

  First, the focus of the present inventors will be described using a comparative example.

  In the case of forming isolated fine particles, it is necessary to go through a plurality of steps including the above-mentioned nanoimprint technology, and there are various candidates in each step. It is no exaggeration to say that is infinite. Of these, two methods that are particularly effective as methods for efficiently forming a fine pattern will be described as comparative examples. However, both methods have some problems.

  The first method and its problems will be described with reference to FIG. First, in FIG. 2A, a base plate 201 on which a concave / convex pattern to be formed and a concave / convex reversed master 201 and an ultraviolet curable resin 202 are prepared is prepared. Next, in FIG. 2B, the master 201 and the base material 203 are bonded together. Next, in FIG. 2C, the ultraviolet curable resin 202 is cured by the ultraviolet irradiation device 204. In this step, since the ultraviolet curable resin 202 is sandwiched between the master 201 and the base material 203, it is necessary that either the master 201 or the base material 203 has a high transmittance for ultraviolet rays. Yes, the ultraviolet ray is irradiated from the side that transmits the ultraviolet ray. Next, in FIG. 2D, the master 201 is peeled off to obtain a pattern on the ultraviolet curable resin 202 with the concavities and convexities reversed from the master 201. Next, in FIG. 2E, a recording film 205 is formed on the ultraviolet curable resin 202 by a thin film forming apparatus such as a magnetron sputtering apparatus or a vacuum evaporation apparatus. Here, a recording film is easily formed on the convex head portion 206, and a recording film is hardly formed on the tapered portion 207. This tendency is more prominent when the straightness of the particle ions flying from the target during film formation is high. In particular, in order to form a fine particle pattern in isolation, it is preferable that the taper portion 207 has no recording film. However, in practice, the recording film formed on the tapered portion 207 is not 0, no matter how a film forming apparatus having high straightness is used. This is due to the shape of the concavo-convex pattern formed on the base material. FIG. 2F shows an enlarged view of the fine particle pattern. When the fine pattern is transferred using the optical nanoimprint method, the taper angle α of the fine particle pattern shown in the drawing does not become larger than 90 °. This is because if the angle α is larger than 90 °, it is impossible to peel off the master 201 in the process of FIG. For this reason, the master 201 for optical imprinting is designed so that α does not exceed 90 °, that is, the concave portion does not have an inversely tapered shape. Therefore, when the fine particle media is created by this method, it is difficult to completely isolate the adjacent convex portions.

  The second method and its problems will be described with reference to FIG. First, in FIG. 3A, a base plate 301 on which a concave / convex pattern to be formed and a master 301 with the concave / convex reversed, an ultraviolet curable resin 302 and a recording film 303 are prepared. Next, in FIG. 3B, the master 301 and the base material 304 are bonded together. Next, in FIG. 3C, the ultraviolet curable resin 302 is cured by the ultraviolet irradiation device 305. At this time, it is necessary that the master 301 or both the base material 304 and the recording film 303 have a high transmittance with respect to the ultraviolet rays, and the ultraviolet rays are irradiated from the side that transmits the ultraviolet rays. Next, in FIG. 3D, the master 301 is peeled off. Next, the resin and the recording film are etched using an etching apparatus. When this substrate is etched, the resin protrusion 306 has a larger resin thickness than the resin recess 307. Therefore, when the etching process is performed under the condition that the thickness of the resin recess 307 is removed, FIG. As shown in (E), only the resin 308 remains on the recording film 303. Further, when etching is performed using the resin 308 as a mask and the exposed recording film is etched, only the isolated recording film 309 can be left as shown in FIG.

  However, in this case, the etching rate of the resin 308 and the recording film 303 is important. That is, if the resin 308 does not remain as a mask during etching of the recording film 303, it cannot function as a mask.

  The etching rate of each material depends on the conditions of the etching apparatus and the type of gas introduced during etching. It is said that the etching rate during dry etching is mainly limited by two actions.

  One is the effect of being knocked out and scraped by physical collision of ions, and these are due to the mechanical strength of the material, the glass transition temperature, and the bonding force between metal ions in the case of metal. Since the ultraviolet curable resin 302 is an organic substance and the recording film 303 is an inorganic substance such as a metal or a dielectric, the ultraviolet curable resin 302 has an overwhelmingly higher etching rate.

  The other is that a by-product is produced by a chemical reaction with the gas, and the speed varies greatly depending on whether or not the boiling point of this by-product is higher than the temperature in the apparatus.

Here, in order to increase the etching rate of the recording film 303 compared to the resin 308, it is necessary to increase the etching rate of the inorganic material rather than the organic material. Therefore, the chemical reaction rate of the recording film 303 must be increased by the gust chemical reaction. No. Cl ₂ , F and Br are well known as highly reactive gases. Actually, the boiling point of the by-product of the recording film 303 and these reactive gases is investigated, and a reactive gas capable of forming a by-product having a low boiling point is introduced at the time of etching. Can be made faster. However, these gases cause a chemical reaction with the metal film, damage the recording film, and become a factor that significantly impairs the recording characteristics. Therefore, in order to isolate the recording film 303, it is necessary to reduce the thickness of the recording film or use a recording film material having a high etching rate, which places restrictions on the selection of the recording film material.

  Embodiments of the present invention based on these points of focus will be described in detail below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, an example of a recording medium substrate, a recording medium, and a manufacturing method thereof will be described. However, a product to be produced is not limited to a recording medium on which information is recorded. We propose a method that can form an isolated metal film by uniformly forming a convex pattern with a reverse taper shape in the nano order, and can be used in the semiconductor and electronic device fields that require such a fine pattern. is there.

  FIG. 7 is a flowchart showing the manufacturing method according to the embodiment.

  The substrate manufacturing method according to the embodiment includes a recess forming step for forming a recess in an organic material on a base material, an SOG applying step for applying SOG onto the recess, and a portion of the SOG by removing a portion of the SOG. A first etching step of exposing the exposed organic material, and a second etching step of removing the exposed organic material and forming a convex portion made of SOG having an inversely tapered shape.

  Further, the recording medium manufacturing method in the embodiment includes a recording layer forming step of forming a recording film on the prepared substrate in addition to the steps of the above-described substrate manufacturing method.

  First, a method for producing, for example, isolated fine particles using a method for producing a substrate (for example, a recording medium substrate) according to an embodiment of the present invention will be described with reference to FIG.

(1) Formation of concave portion First, a concave portion forming step of forming a concave portion in an organic material (for example, resin 102) on a base material is performed.

For example, in the imprint as mainly described in the present embodiment, since the transfer is repeated twice, the unevenness of the master and the final substrate is not reversed. Accordingly, in FIG. 1A, the master 101 is prepared with the same uneven pattern having the shape of the substrate to be created. The material of the master is not particularly limited. However, since the mechanical accuracy of the pattern depends on the accuracy of the master, a material having a small coefficient of thermal expansion such as SiO ₂ is preferable when thermal imprinting is used. Note that, in both optical imprinting and thermal imprinting, a material having high mechanical strength such as nickel, glass or silicon is preferable in order to apply pressure at the time of bonding. As the resin 102, a thermosetting resin or a thermoplastic resin is selected in the case of thermal imprinting, and a photocurable resin is selected in the case of optical imprinting. Although these methods are not particularly limited, it can be said that the optical imprint is more suitable for productivity in consideration of the processing time for one sheet.

  Resin 102 is formed on base material 103. As the material of the base material 103, a material having high mechanical accuracy is preferable, and SiO2, silicon, a single crystal substrate, or the like is suitable. This is because the mechanical accuracy of the master 101 is high, and unless the mechanical accuracy of the base material 103 is as high as that, pressure is not uniformly applied when the bonding is pressed.

  When optical imprinting is selected, either the master 101 or the base material 103 needs to be transmissive to ultraviolet rays.

  Note that as a method of applying the resin 102, a spin coating method or an ink jet method is preferable.

  In FIG. 1B, the master 101 and the base material 103 are bonded together. At this time, it is preferable to bond in a vacuum so that bubble defects do not enter. Alternatively, bonding the master 101 and the base material 103 so as to extrude air is also effective as a method of bonding without introducing bubble defects.

  In FIG. 1C, the resin 102 is cured. In the case of optical imprinting, an ultraviolet irradiation device 104 is used. The ultraviolet irradiation device 104 irradiates from the master side when the master 101 is transparent to ultraviolet rays, and from the base material side when the base material 103 is transparent to ultraviolet rays. In the case of thermal imprinting, after bonding, the temperature of the resin 102 is raised so as to be equal to or higher than the glass transition temperature. Is cured.

  In FIG. 1D, when the master 101 is peeled off, a fine pattern having a concavo-convex pattern reversed from that of the master 101 is transferred onto the resin 102.

  The recess forming step may be performed by lithography or etching. However, the imprint described above is preferable because of high productivity.

(2) SOG application SOG (Spin-On-Glass) will be described. SOG is a liquid resin material in which a SiO ₂ -based material is dissolved in a solvent. As a coating method, a spin coating method is generally used, and SOG can be applied so as to fill the concave portion. Note that SOG may be applied by an inkjet method.

  SOG has the property of vitrifying by causing a dehydration reaction. For induction of the dehydration reaction, sintering at 400 to 1000 ° C. is generally used, and it has been introduced in the semiconductor field as a substrate smoothing process. In addition, since vitrification is induced by electron beam or radical irradiation, it has been reported as a high-resolution resist for electron beams. It has also been reported that vitrification occurs even with O2 plasma. In this embodiment, this phenomenon is introduced into the process by utilizing the crowing phenomenon in the O 2 plasma.

  An SOG coating process is performed in which SOG is coated on the concave portion of the organic material on the base material. For example, as shown in FIG. 1E, SOG 105 is applied by a spin coating method to fill the concave portion of the resin 102.

(3) Etching First, a first etching process is performed in which a part of the SOG is removed to partially expose the organic material. For example, after the substrate shown in FIG. 1E is placed in a chamber of a plasma etching apparatus and evacuated, an O ₂ gas is allowed to flow to perform an etching process. At this time, the vitrification phenomenon occurs simultaneously with the etching of the SOG, and the SOG is transformed into SiO ₂ . By controlling the etching time, the processing is stopped when the resin is exposed as shown in FIG. At this time, all the SOGs 106 embedded in the recesses of the resin 102 are vitrified and have a reverse taper shape.

From here, in order to isolate SOG as shown in FIG. 1G, it is necessary to remove the resin 102 between the SOGs. That is, the exposed organic material is removed, and a second etching process is performed to form a convex portion made of SOG having an inversely tapered shape. This can be performed by wet etching or dry etching. In the case of wet etching, it is preferable to use a solvent in which the resin is dissolved and to immerse for a time during which a desired portion of the resin is dissolved. Further, in the case of dry etching, only the resin 102 can be selectively removed by continuing O ₂ etching continuously. Although the etching rate varies depending on the specifications of the etching apparatus and the etching conditions, the etching rate ratio between SiO ₂ and the organic material generally exceeds 20. For this reason, since the resin is selectively removed, the shape shown in FIG. 1G is obtained, and the vitrified SOG 107 has an inversely tapered shape.

  Note that since the region sandwiched between the SOG and the substrate is difficult to etch, the resin 108 remains. However, if the etching time is too long, the resin 108 part is dissolved, and it is difficult to fix the vitrified SOG 107 on the substrate. For this reason, it is necessary to control the etching time so that the resin 108 part does not disappear, and this applies to both dry etching and wet etching.

(4) Recording film formation The recording film formation process which forms a recording film on the board | substrate produced by said (1)-(3) is performed.

  Whether it is a magnetic recording medium or an optical memory, the material used for the recording film is a metal film. In addition, since these may be oxidized by being in contact with the air or resin, or may be corroded by being ionized, a dielectric material may be formed before and after the recording film as a protective film. Any of these materials can be formed as a thin film by a magnetron sputtering apparatus, a vapor deposition apparatus or the like. Also in this embodiment mode, a normal film forming apparatus can be used. The substrate shown in FIG. 1G is put into a film forming apparatus to form a desired recording film. The metal film is struck onto the substrate by the film forming apparatus, and the film is formed. However, since the metal particles cannot wrap around the wall surface of the reverse taper 107 at this time, the recording film is formed on the wall surface. Not formed. Therefore, as shown in FIG. 1H, the recording film 109 on the SOG is isolated from the adjacent recording film portion.

  In the embodiment of the present invention, for example, isolated fine particles can be produced through the steps (1) to (4). Hereinafter, embodiments will be described in more detail including specific materials and process conditions.

(Embodiment 1)
In the present embodiment, a method of forming a recording film by using a photoimprint method, transferring a dot pattern, removing a resin between SOGs by a dry etching method, and more specifically will be described.

  First, the recessed part formation process was performed.

In FIG. 4A, a silicon wafer was used as the base material 401. An ultraviolet curable resin (manufactured by Maruzen Petrochemical Co., Ltd., MUR-XR01) was diluted with polypropylene glycol monomethyl etaacetate (commonly called PGMEA) on the base material 401 and applied by a spin coat method. Mixing and stirring MUR-XR01 to 10 wt% and PGMEA to 90 wt%, rotating 120 (sec) at a rotation speed of 1000 (rpm), and evaporating the solvent, the UV curable resin 402 is formed with a thickness of 30 nm. Could be formed. As the master 403, a master is used in which the material is quartz, the diameter of the convex part is 30 nm, and the height is 30 nm, and dots are arranged squarely at intervals of 60 nm. This was placed in a chamber of a nanoimprint apparatus (scivax x-300) and bonded as shown in FIG. Further, the ultraviolet curable resin was cured by the ultraviolet irradiation device 404 while applying a pressure of 100 kg / cm ² from both sides and applying the pressure.

  Next, the master 403 was peeled off, and a concave hole pattern was formed on the ultraviolet curable resin 402 as shown in FIG. The upper part of FIG. 4C represents a cross-sectional view of a pattern formation region, and the lower part of FIG. 4C represents a hole pattern when the substrate is observed from the arrow 405 side. Here, the distance indicated by 406 in the drawing, that is, the thickness of the convex portion of the ultraviolet curable resin 402 is 36 nm, and the distance indicated by 407 in the drawing, that is, the thickness of the concave portion of the ultraviolet curable resin 402 is 6 nm. It was confirmed using AFM (Atomic Force Microscope).

  Next, an SOG coating process was performed.

  That is, hydrogen silsesquioxane (commonly known as HSQ, manufactured by Toray Dow Corning Co., Ltd., FOX-15), which is a kind of SOG, was applied to the hole pattern. 15 wt% of HSQ and 85 wt% of methyl isobutyl ketone (commonly called MIBK) were prepared and stirred, and then rotated for 120 (sec) at a rotation speed of 1000 (rpm) to evaporate MIBK as a solvent. As a result, as shown in FIG. 4D, the concave portion of the ultraviolet curable resin 402 could be filled with HSQ. At this time, it was confirmed by AFM that the thickness of HSQ indicated by 408 in the figure was 10 nm. Further, when the surface layer was measured by AFM, it was confirmed that there was a recess 409 having a diameter of 5 nm and a diameter of 5 nm.

  In this example, it was confirmed that MUR-XR01, an ultraviolet curable resin, was insoluble in MIBK after curing. As the solvent for HSQ, it is necessary to select a solvent that does not dissolve the ultraviolet curable resin.

  Next, a first etching process and a second etching process were performed.

That is, this substrate was put into a chamber of an etching apparatus (Shinko Seiki, POEM), and the pressure was reduced until the pressure became 0.1 Pa. Next, the inside of the chamber was evacuated with a vacuum apparatus so as to keep the inside of the chamber at 30 Pa while oxygen was introduced at a flow rate of 100 sccm. In this atmosphere, an oxygen plasma treatment was performed using an RF power source at a power of 200 (W) for 3 minutes. By this oxygen plasma treatment, the liquid HSQ was vitrified and transformed into SiO ₂ .

The etching rate ratio between the ultraviolet curable resin 402 and SiO ₂ is 1/30, and the rate at which the ultraviolet curable resin 402 is removed is overwhelmingly fast. For this reason, the ultraviolet curable resin 402 is selectively removed, and only the ultraviolet curable resin between the HSQs is removed as shown in FIG. 4E, and the reversely tapered HSQ 410 and the ultraviolet curable resin portion immediately below the HSQ 410 are removed. Only 411 remained.

  Next, a recording film forming step was performed.

  That is, this substrate was put in a chamber of a magnetron sputtering apparatus and evacuated to a vacuum, and then SiN 10 nm, GeSb 10 nm, and SiN 10 nm were sequentially stacked.

  FIG. 4F shows a cross-sectional view after film formation and an external view seen from above. In the figure, the stacked films formed are collectively shown as a recording film 412 and a recording film 413. Since a film such as SiN or GeSb is not formed on the inclined surface portion of the reverse taper of HSQ, an isolated recording film can be formed as shown in the figure. Therefore, the recording film 412 stacked on the reverse tapered HSQ 410 is independent of the recording film 413 formed in the adjacent trench portion, and therefore can exist as isolated fine particles.

  According to the present embodiment, the configuration of the recording medium can be designed without limiting the material and thickness of the recording film.

  Note that if the pattern shape of the master 403 is reduced, the inversely tapered HSQ is also reduced accordingly, which is suitable for pattern miniaturization.

  Note that a magnetic layer 512 as described in the second embodiment may be formed on the dot pattern created by the method of the first embodiment.

  The dot pattern may be formed by a thermal imprint method as described in the second embodiment.

(Embodiment 2)
In the present embodiment, a method of forming a magnetic film by transferring a line pattern using a thermal imprint method, removing a resin between SOGs by a wet etching method, and more specifically will be described.

  First, the recessed part formation process was performed.

In FIG. 5A, quartz glass having a thickness of 0.6 mm was used as the base material 501. A material having a glass transition temperature of 140 ° C. was selected using a cycloolefin polymer (ZEONOR manufactured by Nippon Zeon Co., Ltd.) as the thermoplastic resin 502. The mixture was prepared by mixing 99 wt% of acetone with respect to 1 wt% of the cycloolefin polymer, dissolved by stirring, and applied by spin coating. The thermoplastic resin 502 was able to be formed with a thickness of 35 nm by rotating 120 (sec) at a rotation speed of 1000 (rpm) and evaporating acetone. As the master disk 503, a master disk in which materials of silicon, a line width of 40 nm, and a height of 50 nm are arranged at intervals of 80 nm is employed. This was installed in a chamber of an imprint apparatus (scivax x-300). As shown in FIG. 5B, a base material 501 coated with a master 503 and a thermoplastic resin 502 is sandwiched between an upper mold 504 and a lower mold 505, and a pressure of 10 kg / cm ² is applied at room temperature. The temperature gradually increased from. The resin temperature is controlled by a heater (not shown) installed inside the upper mold 504 and the lower mold 505. When the temperature of the thermoplastic resin 502 was 160 ° C., the applied pressure was increased to 200 kg / cm ² . After maintaining at this temperature and pressure for 1 minute, the temperature was lowered to room temperature while a pressure of 200 kg / cm ² was applied.

  Next, the substrate was released from the mold, taken out from the imprint apparatus, the master 503 was peeled off, and a concave line pattern was formed on the thermoplastic resin 502 as shown in FIG. The upper part of FIG. 5C represents a cross-sectional view of a pattern formation region, and the lower part of FIG. 5C represents a line pattern when the substrate is observed from the arrow 506 side. Here, the distance indicated by 507 in the drawing, that is, the thickness of the convex portion of the thermoplastic resin 502 is 60 nm, and the distance indicated by 508 in the drawing, that is, the thickness of the concave portion of the thermoplastic resin 502 is 10 nm. Was confirmed using an AFM (atomic force microscope).

  Next, an SOG coating process was performed.

That is, a coating solution for forming an organic SiO ₂ film, which is a kind of SOG (manufactured by Tokyo Ohka Kogyo Co., Ltd., hereinafter referred to as SOG) was applied to this line pattern. After 5 wt% SOG and 95 wt% PGMEA were mixed and stirred, the mixture was rotated at 120 rpm for 1000 rpm and the solvent PGMEA was evaporated. As a result, the concave portion of the thermoplastic resin 502 could be filled with the SOG 509 as shown in FIG. At this time, it was confirmed by AFM that the thickness of the SOG indicated by 510 in the figure was 40 nm. Further, when the surface layer was measured by AFM, no dent was observed, so that it was confirmed that the concave portion of the thermoplastic resin 502 was completely filled with SOG.

  Next, a first etching process was performed.

That is, this was put in the chamber of an etching apparatus (Shinko Seiki, POEM), and pressure was reduced until the pressure became 0.1 Pa. Next, the inside of the chamber was evacuated with a vacuum apparatus so as to keep the inside of the chamber at 20 (Pa) while introducing Ar gas at a flow rate of 50 sccm. In this atmosphere, Ar plasma treatment was performed for 2 minutes at a power of 100 (W) using an RF power source to remove SOG having a thickness of 40 nm. By this Ar plasma treatment, SOG that was in a liquid state was vitrified and transformed into SiO ₂ . By this plasma treatment, as shown in FIG. 5 (E), SOG511 having a reverse taper shape and SiO ₂ was formed in the concave portion of the thermoplastic resin 502.

  Thereafter, a second etching process was performed.

  That is, this substrate was immersed in acetone for 1 hour to perform wet etching. By this treatment, the thermoplastic resin 502 is selectively removed, and only the thermoplastic resin between the SOGs is removed as shown in FIG. 5F, and only the reverse-tapered SOG and the ultraviolet curable resin part just below it are removed. Remained.

  Next, a recording film forming step was performed.

  That is, the substrate is placed in a chamber of a vapor deposition apparatus and evacuated to a vacuum, and then a SUL layer made of a soft magnetic material is formed to a thickness of about 50 nm. Here, as a material of the SUL layer, for example, CoZr, CoZrNb, CoZrTa-based alloy and the like can be raised. Next, an intermediate layer made of a nonmagnetic material is formed on the SUL layer to a thickness of about 10 to 20 nm. As the material for the intermediate layer, Ru, Pt, Pd, W, Ti, Ta, Cr, Si, alloys containing these, or oxides and nitrides thereof can be used. Then, a recording layer is formed to a thickness of about 20 nm on the intermediate layer. As a material for the recording layer, CoCrPt can be raised. These SUL layer, intermediate layer, and recording layer can form a magnetic layer 512 (recording film) of a perpendicular magnetic medium.

  Since none of these layers adhere to the wall surface of the reverse tapered SOG, the magnetic layer 512 formed on the SOG is physically isolated from the adjacent track.

  Note that the recording film 412 described in the first embodiment may be formed on the line pattern created by the method of the second embodiment.

  The line pattern may be formed by the optical imprint method as described in the first embodiment.

(Embodiment 3)
In this embodiment, a method for forming SOG as a protective layer will be described.

  In addition to the manufacturing method described in the first or second embodiment, the manufacturing method according to the third embodiment includes a second SOG application step of applying SOG onto the substrate on which the recording film is formed. The periphery of the upper recording film is embedded with SOG.

  Although embodiments of the present invention relate to a recording medium, smoothness of the surface of the recording medium may be required when reading a signal. If the recording medium is smooth, it may be easy to maintain a constant distance from the reading head during information recording and reproduction. Also, in the case of a read head that swings, there is a strong correlation between the surface roughness of the recording medium and the frictional force. Therefore, improving the surface properties as much as possible reduces the frictional force generated between the head and the recording medium. There is.

  In the recording medium proposed in the first and second embodiments, the recording film portion protrudes as a convex portion. Therefore, the material around the recording film is high in mechanical strength and excellent in chemical stability. It is preferable to cover with.

  The embodiment will be described with reference to FIG. In the recording medium in FIG. 6A, a base material 601 is a sapphire substrate, 602 is an ultraviolet curable resin, 603 is an HSQ material, and the shape is reverse tapered. Since the recording film GeSbTe 604 is formed on such a substrate with a thickness of 20 nm, the recording film 604 portion is more independent from the other portions. The height from the surface layer of the base material 601 to the upper part of the recording film 604 including the HSQ 603 and the UV curable resin 602 is 80 nm, and the convex portion has a hexagonal close-packed structure with a diameter of 50 nm on the pillar and a track pitch of 100 nm. Arranged.

  Hydrogen silsesquioxane (commonly known as HSQ, manufactured by Toray Dow Corning Co., Ltd., FOX-15) was applied on the recording medium of FIG. 40 wt% of HSQ and 60 wt% of MIBK were mixed and stirred, and then rotated for 120 (sec) at a rotation speed of 1000 (rpm) to evaporate MIBK as a solvent. With this process, the recording medium could be covered with HSQ 605 as shown in FIG. Further, when the surface of the base material 601 was exposed by partially marking with tweezers and the step was measured by AFM, it was found that the distance from the surface layer of the base material 601 to the surface layer of the HSQ 605 was 100 nm.

  Next, this recording medium was put in an annealing furnace (not shown) and sintered at 1000 ° C. for 30 minutes to completely vitrify HSQ605.

  After annealing, the surface of the HSQ 605 was measured by AFM. As a result, the surface roughness Ra was as small as 0.1 nm, so the HSQ 605 is also useful as a protective coating.

  In this embodiment, sintering is used for vitrification of HSQ. However, when a high temperature cannot be applied to the recording medium, an oxygen etching process or the like is effective.

  As described above, the manufacturing method according to the embodiment has the following configuration in one aspect.

  That is, the substrate manufacturing method in the embodiment includes a recess forming step for forming a recess in an organic material on a base material, an SOG coating step for applying SOG onto the recess, and removing an organic material by removing a part of the SOG. It includes a first etching step for partially exposing and a second etching step for removing the exposed organic material and forming a convex portion made of SOG having an inversely tapered shape.

  According to the above configuration, it is possible to manufacture a substrate having a reverse-tapered convex portion with small variation in size and high positional accuracy.

  In the substrate manufacturing method according to the embodiment, SOG may be a material that vitrifies by causing a dehydration reaction.

  In the method for manufacturing a substrate in the embodiment, the first etching step removes SOG applied to portions other than the recesses of the organic material, and vitrifies the SOG applied to the recesses of the organic material. Also good.

  According to the above configuration, it is possible to form a reverse-tapered convex portion having a smaller size variation and higher positional accuracy on the substrate.

  In the method for manufacturing a substrate in the embodiment, the organic material may be a material that is more easily etched in the second etching step than vitrified SOG.

  Moreover, in the manufacturing method of the board | substrate in embodiment, a recessed part formation process may form the recessed part of a reverse taper shape.

  In the substrate manufacturing method according to the embodiment, the SOG application step may apply SOG so as to fill the concave portion having the inverse taper shape.

  According to the above configuration, it is possible to more reliably form the reverse tapered convex portion on the substrate.

  In the method for manufacturing a substrate in the embodiment, the first etching step may be oxygen etching.

  Further, the recording medium manufacturing method in the embodiment includes each step of the substrate manufacturing method in the embodiment and a recording layer forming step of forming a recording film on the produced substrate. At this time, the recording film on the convex portion made of SOG is separated from the recording film in another adjacent region.

  According to the configuration described above, it is possible to manufacture a recording medium having a recording area having an isolated recording film with small variation in size and high positional accuracy.

  Further, the recording medium manufacturing method according to the embodiment may include a second SOG application step of applying SOG onto the substrate on which the recording film is formed. At this time, the periphery of the recording film on the convex portion may be embedded with SOG.

  According to the above configuration, the surface of the recording medium can be smoothed.

  Moreover, the substrate and the recording medium in the embodiment have the following configurations in one aspect.

  In other words, the substrate in the embodiment has an organic substance between a convex portion made of SOG having an inversely tapered shape and a base material.

  In the substrate in the embodiment, the organic substance may be an ultraviolet curable resin.

  In the substrate in the embodiment, the organic substance may be a thermoplastic resin.

  In addition, the recording medium in the embodiment includes the substrate of the embodiment, and a recording film that is isolated from a metal film in another region is provided on the SOG.

  In the recording medium in the embodiment, the periphery of the isolated recording film may be embedded with the SOG material.

  The method for manufacturing a substrate of a recording medium according to the present invention can easily duplicate a fine concavo-convex pattern, has a short production time, and can be mass-produced. In addition, it is easy to prepare production equipment because it uses industrially versatile and proven general equipment.

101 Master 102 Resin 103 Base material 104 Ultraviolet irradiation device 105 SOG
106 SOG with SiO ₂
107 SOG
DESCRIPTION OF SYMBOLS 108 Resin 109 Recording film on SOG 201 Master disk 202 UV curable resin 203 Base material 204 UV irradiation device 205 Recording film 206 Convex-shaped top part 207 Taper part 301 Master disk 302 UV curable resin 303 Recording film 304 Base material 305 UV irradiation Device 306 Resin convex portion 307 Resin concave portion 308 Resin 309 Isolated recording film 401 Base material 402 UV curable resin 403 Master disc 404 UV irradiation device 405 Arrow 406 UV curable resin convex thickness 407 UV curable resin concave portion Thickness of 408 HSQ thickness 409 Recess on HSQ 410 Reverse-tapered HSQ
411 UV curable resin 412 HSQ upper recording film 413 Trench recording film 501 Base material 502 Thermoplastic resin 503 Master disc 504 Upper mold 505 Lower mold 506 Arrow 507 Thermoplastic resin convex thickness 508 Thermoplastic resin thickness 508 Recess thickness 509 SOG
510 SOG thickness 511 SiO ₂ SOG
512 Magnetic layer 601 Base material 602 UV curable resin 603 HSQ
604 recording film 605 HSQ

Claims (14)

A recess forming step for forming a recess in the organic material on the base material;
An SOG application step of applying SOG onto the recess;
A first etching step of removing a portion of the SOG to partially expose the organic material;
And a second etching step of removing the exposed organic material and forming a convex portion made of SOG having an inversely tapered shape. The SOG is a material that vitrifies by causing a dehydration reaction.
The manufacturing method of the board | substrate of Claim 1. The first etching step removes SOG applied to portions other than the recesses of the organic material, and vitrifies the SOG applied to the recesses of the organic material.
The manufacturing method of the board | substrate of Claim 2. The organic material is a material that is more easily etched in the second etching step than the vitrified SOG.
The manufacturing method of the board | substrate of Claim 3. The concave portion forming step forms a concave portion having a reverse taper shape.
The manufacturing method of the board | substrate of Claim 4. In the SOG application step, SOG is applied so as to fill the concave portion having the reverse taper shape.
The manufacturing method of the board | substrate of Claim 5. The method for manufacturing a substrate according to claim 1, wherein the first etching step is oxygen etching. Each process of the manufacturing method according to claim 1,
A recording layer forming step of forming a recording film on the substrate produced by the manufacturing method according to claim 1,
A method for producing a recording medium, wherein the recording film on the convex portion made of SOG is separated from the recording film in another adjacent region. A second SOG coating step of coating SOG on the substrate on which the recording film is formed;
The method for manufacturing a recording medium according to claim 8, wherein the periphery of the recording film on the convex portion is embedded with SOG. A substrate comprising an organic substance between a convex part made of SOG having an inversely tapered shape and a base material. The substrate according to claim 10, wherein the organic substance is an ultraviolet curable resin. The substrate according to claim 10, wherein the organic substance is a thermoplastic resin. A substrate according to any one of claims 10 to 12,
A recording medium having a recording film isolated from a metal film in another region above the SOG. 14. The recording medium according to claim 13, wherein the periphery of the isolated recording film is embedded with an SOG material.

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