JP2010118106A - Method of manufacturing substrate for information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a substrate for an information recording medium, which manufactures a high-quality information recording medium substrate having a microstructure, breakage-resistance or scratch-resistance, and easily released from the mold. <P>SOLUTION: The method of manufacturing the substrate for the information recording medium includes steps of:transferring a concavo-convex structure into a molding material 3 by pressing a mold 1 with the concavo-convex structure 1a into the molding material 3 to be formed on the substrate base 2; hardening the molding material 3 while being pressed by the mold 1; and releasing the mold 1 from the hardened molding material 3. When releasing the mold 1, the hardened molding material 3 and mold 1 are immersed in liquid immersing material 4 which is liquid when the molding material 3 is hardened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an information recording medium substrate using a nanoimprint method in which a fine pattern is transferred to a substrate.

  For magnetic recording media, patterned media (hereinafter referred to as PM) in which the magnetic layer is patterned and the magnetic layer is physically divided into a plurality of regions have been proposed in order to further increase the recording density. The fine structure for PM is on the order of several tens of nm, which is a pattern size equivalent to the diffraction limit of light. For this reason, it is difficult to produce a PM pattern with a fine structure by general photolithography. Therefore, as a method capable of further fine processing, for example, a method of forming a pattern by a nanoimprint method has been proposed. In the nanoimprint method, first, the concave / convex shape of the above mold is transferred to the imprint material by pressing a mold having a concave / convex shape on the surface against the imprint material applied on the substrate substrate, and the concave / convex shape is transferred. This is a method of obtaining a substrate having a concavo-convex shape on the surface by peeling the mold after solidifying the imprint material. The nanoimprint method is described in Patent Document 1, for example. Specifically, Patent Document 1 discloses a process of forming a transfer target (imprint material layer) on a flat substrate or a mold (mold) having an uneven structure, and bringing the mold into contact with the transfer target. A step of pressing, a step of transferring the concavo-convex structure of the mold to the transferred body, a step of peeling the mold from the transferred body, and a magnetic recording layer on the transferred body onto which the concavo-convex structure of the mold is transferred. And a method of manufacturing a magnetic recording medium having a step of depositing. Thus, by using the nanoimprint method, even a pattern size in a region exceeding the diffraction limit of light required in PM can be processed.

  However, in the nanoimprint method, when the mold is transferred to the transfer target, the mold and the transfer target are firmly adhered to each other, so that there is a problem that it is difficult to peel off the mold. Depending on how the force is applied at the time of peeling, the transferred fine structure may be destroyed or deformed.

Therefore, various techniques have been proposed to solve the above problems. As a method for preventing breakage at the time of mold release, for example, in Patent Document 2, a pin module is inserted between a mold and a substrate after imprint molding is completed, the mold and the substrate are separated, and a slit is formed. A method is described in which the air is introduced between the mold and the substrate through this slit to break the vacuum effect, and the substrate is separated from the mold by the pin module. Further, in Patent Document 3, in an imprint mold (mold) for forming a concavo-convex pattern, a through-hole is formed outside the concavo-convex pattern region on the surface on which the concavo-convex pattern is formed. A method is described in which a mold is peeled off by applying pressure from a through-hole to a substrate with a pin or gas after pattern formation between them. This prevents damage to the fine structure when the mold is peeled off.
JP 2007-95162 A JP 2007-118552 A JP 2008-78550 A

  However, in the method described in Patent Document 2 described above, a pin module is inserted between the mold after imprint molding is completed and the substrate, and a gap is generated between the mold and the substrate by physical force. Therefore, when the pin module comes into contact with the substrate, there is a high possibility that the substrate is damaged by the pin module. In particular, in a hard disk drive (hereinafter referred to as HDD) substrate in which PM is used, the distance between the HDD substrate and the data reading head is only about 10 nm, and there is a protrusion such as a scratch on the surface of the HDD substrate. There is a problem that a so-called head crash occurs in which the head and the HDD substrate are destroyed by contact with the head. Therefore, the scratches on the substrate are often a problem even if they are minute scratches.

  Further, in the method described in Patent Document 3, depending on the position of the through-hole, no pressure is uniformly applied to the entire substrate, resulting in poor balance, and pattern damage or deformation may occur. For example, in the case of a 2.5-inch substrate for an HDD substrate, for example, a region where a pattern is not formed is only a few millimeters from the inner periphery and the outer periphery with respect to a donut shape having an outer diameter of 65 mm and an inner diameter of 20 mm. Therefore, the region where the through hole can be formed is very limited. Therefore, in order to release the substrate uniformly, the through hole cannot be formed at an optimum position. Conversely, if a through hole is formed at a position suitable for uniform mold release, a pattern is not formed in the vicinity of the through hole formation location, so that the recording capacity is reduced correspondingly, and it is difficult to increase the recording density. .

  Furthermore, when mold release is performed in an apparatus, the mold and the substrate vibrate due to noise such as vibration of the apparatus. Damage may occur. In addition to the vibration of the apparatus, external forces may be applied to the mold and the substrate due to disturbances such as wind, and the fine structure may be damaged.

  The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent the breakage of the fine structure or damage to the substrate, and to allow easy release, and to provide a high-quality information recording medium substrate. An object of the present invention is to provide a method for manufacturing an information recording medium substrate that can be manufactured.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the method for manufacturing an information recording medium substrate according to an aspect of the present invention includes a step of pressing a mold having a concavo-convex structure onto a molding material formed on a substrate base material and transferring the concavo-convex structure to the molding material. And a step of solidifying the molding material in a state where the mold is pressed, and a step of releasing the mold from the solidified molding material. The step of releasing the mold includes the step of solidifying the molding material. In this state, the molding material and the mold are immersed in a dipping substance that is liquid.

  Thus, by performing mold release in the liquid, the liquid penetrates between the mold and the solidified molding material. Since the viscosity of liquid is higher than that of air, the microstructure transferred to the molding material is used to reduce the impact (buffer effect) even when the mold collides with the molding material during release. Is almost never damaged. Therefore, when the mold release is performed by the apparatus, the fine structure is hardly damaged during the mold release due to noise such as vibration of the apparatus. In addition to the vibration of the device, even when an external force is applied to the mold or the solidified molding material at the time of mold release due to disturbance such as wind, the microstructure is similarly damaged by the buffering effect of the liquid. There is almost nothing. In addition, since the solidified molding material and the periphery of the mold are covered with a liquid, capillary adhesion does not occur, and the mold can be easily released with a small force. In this way, a defective product or the like hardly occurs, and a high-quality information recording medium substrate can be manufactured.

  Here, the capillary bonding will be described with reference to FIG. FIG. 6 is a diagram for explaining capillary bonding. As shown in FIG. 6, in the two disc-shaped substrates 101 and 102 opposed to each other, the gap between them is very small with respect to the radius of the substrates 101 and 102, and the liquid 103 exists in the gap. When the surroundings are the atmosphere, a strong force is required due to the surface tension of the liquid 103 to separate the substrates 101 and 102 from each other. Specifically, a strong adhesive force is generated between the substrates 101 and 102 due to the pressure difference between the inside and outside of the liquid (difference in Laplace pressure) caused by the surface tension of the liquid, and a strong force is required to separate them. . This phenomenon is called capillary adhesion. For example, in FIG. 6, when the substrates 101 and 102 are both disk-shaped with a radius R, and the liquid 103 that is water exists in the gap H between the substrate 101 and the substrate 102, R = 1 cm and H = 5 μm. In order to separate the substrates 101 and 102, a force of 14 N (≈140 kgf) is required.

  In the method for manufacturing an information recording medium substrate described above, it is preferable that the dipping substance is a substance that does not erode the molding material and the base substrate.

  Thereby, even when the molding material and the mold are immersed in the dipping substance, the molding material and the base substrate are not eroded, and a high-quality information recording medium substrate can be produced.

  Further, in the above-described method for manufacturing an information recording medium substrate, the immersion substance has a property of dissolving the mold, and in the step of releasing the mold, at least a part of the mold is made of the immersion substance. Preferably it is dissolved.

  Thereby, at the time of mold release, it becomes easy to perform mold release because the contact surface with the molding material in the mold dissolves. Therefore, the fine structure is not damaged at the time of mold release, and it is difficult to produce defective products and the like, and a high-quality information recording medium substrate can be manufactured.

  In the above-described method for manufacturing an information recording medium substrate, it is preferable that the immersion material is water.

  As described above, since water that can be easily obtained and does not erode the substrate base material or the like is used as the dipping substance, the mold can be released at low cost.

  According to the present invention, it is possible to provide a method for manufacturing an information recording medium substrate that is difficult to damage a fine structure or damage the substrate, can be easily released, and can produce a high-quality information recording medium substrate. it can.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

  First, a mold according to an embodiment of the present invention will be described with reference to FIG. 1A and 1B are a plan view and a cross-sectional view showing a configuration of a mold according to the present embodiment, wherein FIG. 1A is a plan view showing a configuration of the mold, and FIG. 1B is a cross-section showing a configuration of the mold. FIG. 1B is a cross-sectional view taken along a plane that passes through the center of the main surface of the mold 1 shown in FIG. 1A and is perpendicular to the main surface. As shown in FIG. 1 (A) and FIG. 1 (B), the mold 1 according to the present embodiment has a donut shape having a circular hollow portion at the center of a disk, and an imprint material ( A transfer pattern 1a which is a fine structure (uneven structure) for forming an uneven pattern is formed on the molding material. The mold 1 is manufactured by a known technique such as injection molding, dry etching, wet etching, photolithography, electron beam drawing (electron beam lithography), imprint method, or the like. For example, when injection molding is used, the transfer pattern 1a may be formed by injection molding at the same time. The transfer pattern 1a may be formed by machining or the like. In addition, in this embodiment, although the mold 1 is made into donut shape, it is not necessarily limited to this shape.

  Next, a method for manufacturing an information recording medium substrate using the mold according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a manufacturing process of an information recording medium substrate using the mold according to this embodiment, and FIGS. 2A to 2F are cross-sectional views showing each process. As shown in FIG. 2A, the mold 1 and the glass substrate 2 that is the substrate base material are opposed to each other, and the transfer pattern 1a of the mold 1 is disposed so as to face the glass substrate 2 side that is the substrate base material. . In addition, as a substrate base material, if it is a base material which can form a board | substrate, such as a board | substrate for PM, by providing the surface part which consists of a structural material which has several fine uneven | corrugated shape on the surface, especially if it is a base material Not limited. For example, a quartz substrate or the like may be used instead of the glass substrate. Examples of the glass substrate 2 include a 2.5-inch glass substrate for HDD having a donut shape having a circular hollow portion at the center of a disk.

  Next, as shown in FIG. 2 (B), an imprint material (molding material) 3 is applied to the upper surface of the glass substrate 2 where the uneven pattern is formed. The imprint material 3 may be applied to the mold 1 by reversing the positions of the mold 1 and the glass substrate 2. As the imprint material 3, for example, a spin-on-glass (SOG) material may be used. The application method of the imprint material 3 may be a known application method. For example, the application method may be a drop application using a dispenser, a spin coating method, a dip coating method, or the like. You may spread using an applicator or the like. If the thermal imprint method is used, for example, a cycloolefin-based resin may be used as the imprint material 3, and if the optical imprint method is used, for example, a photoresist is used as the imprint material 3. That's fine.

  Next, as shown in FIG. 2C, the microstructure 1 is transferred to the imprint material 3 by pressing the mold 1 against the glass substrate 3 including the imprint material 3 with a predetermined pressing force. Then, the imprint material 3 is dried. By doing so, the imprint material 3 is solidified. Thereby, an uneven pattern is formed on the imprint material 3. There is no restriction | limiting in particular as said drying method, A well-known drying method can be used. For example, although it may be allowed to stand at room temperature, it is preferable to further reduce the pressure, blow, and heat from the viewpoint of faster drying. Further, when heating is performed, it is preferable that the heating temperature does not exceed the boiling point of the solvent of the imprint material 3. By doing so, the imprint material 3 does not boil, and the possibility that bubbles remain inside the imprint material 3 is reduced, so that the occurrence of irregular transfer defects is suppressed. In addition, since the SOG material is used for the imprint material 3, it is solidified by drying. However, when the thermal imprint method is used, the mold 1 is pressed against the imprint material 3 softened by heating and then cooled. Thus, the imprint material 3 needs to be solidified. Moreover, when using the photoimprint method, it is necessary to solidify the imprint material 3 by irradiating light after pressing the mold 1 against the imprint material 3. Thereby, an uneven pattern is formed on the imprint material 3.

  Next, as shown in FIG. 2D, the mold 1, the imprint material 3, and the glass substrate 2 that are integrated by pressing the mold 1 are immersed in the liquid 4. Here, the liquid 4 which is the immersion material to be immersed may be water, for example. By using water as the dipping substance, the dipping substance can be easily obtained, and the versatility is achieved. Further, the imprint material 3 and the glass substrate 2 are not eroded. Note that the liquid 4 as the dipping substance is not limited to water, and is a liquid under the condition that the imprint material 3 is solidified, and does not erode or break the imprint material 3 and the glass substrate 2. Any substance having any of the above may be used.

  Next, as illustrated in FIG. 2E, the mold 1 is released from the imprint material 3 in a state where the mold 1, the imprint material 3, and the glass substrate 2 are immersed in the liquid 4. The mold release may be performed by a known technique. For example, in this embodiment, as shown in FIG. 2 (E), the pin module 5 may be released by inserting it between the solidified imprint material 3 and the mold 1. By inserting the pin module 5 between the imprint material 3 and the mold 1, a slit is formed between them, and the liquid 4 flows into the slit, and the vacuum effect between the imprint material 3 and the mold 1. By destroying, the imprint material 3 and the mold 1 are separated. At this time, the liquid 4 does not exist only between the imprint material 3 and the mold 1, but the imprint material 3 and the mold 1 are covered with the liquid 4. Therefore, the capillary adhesion phenomenon does not occur, and a large force is not required in the mold release, so that the mold release can be easily performed.

  In addition, since the liquid has a higher viscosity than the gas, it is not easily affected by disturbances during mold release. That is, by releasing the mold in the liquid 4, the liquid 4 penetrates between the mold 1 and the imprint material 3. For example, when mold release is performed by an apparatus, even when the mold 1 and the imprint material 3 vibrate due to noise such as vibration of the apparatus and they collide, the viscosity is higher than that of gas. The shock is reduced by the buffering effect of the liquid 4 and the microstructure transferred to the imprint material 3 is hardly damaged. Further, in addition to the vibration of the device, even when an external force is applied to the mold 1 or the imprint material 3 at the time of releasing due to disturbance such as wind, the fine structure is similarly damaged by the buffering effect of the liquid 4. There is little to be done.

  Next, as shown in FIG. 2 (F), a magnetic film 6 is formed on the imprint material 3, thereby manufacturing an information recording medium substrate 7 having a concavo-convex pattern 6a formed on the surface thereof. For example, CoCrPt or FePt may be used as the magnetic film 6.

  By performing the mold release process in the liquid 4 in this way, the influence of the disturbance on the fine structure of the imprint material 3 is prevented by the buffering effect of the liquid 4, thereby preventing the fine structure from being damaged and manufacturing the information storage medium substrate. Defective products can be reduced. In addition, since the imprint material 3 and the mold 1 are immersed in the liquid 4, they can be easily released without capillary adhesion between the imprint material 3 and the mold 1.

  Next, a method for manufacturing an information recording medium substrate according to another embodiment of the present invention, which is different from the method for manufacturing an information recording medium substrate according to the above-described embodiment of the present invention, will be described. 3A and 3B are a plan view and a cross-sectional view showing the configuration of the mold according to another embodiment of the present invention, in which FIG. 3A is a plan view showing the configuration of the mold, and FIG. It is sectional drawing which shows this structure. 3B is a cross-sectional view taken along a plane that passes through the center of the main surface of the mold 11 shown in FIG. 3A and is perpendicular to the main surface. As shown in FIGS. 3 (A) and 3 (B), the mold 11 according to the present embodiment has a disc shape, and one main surface is used to form an uneven pattern on the imprint material (molding material). A transfer pattern 11a having a fine structure is formed. Further, four through holes 11 b are formed in the main surface of the mold 11, and these are arranged so as to be symmetric four times with respect to the center of the disk-shaped mold 11. The mold 11 is manufactured by a known technique such as injection molding, dry etching, wet etching, photolithography, electron beam drawing, imprinting or the like. For example, when injection molding is used, the transfer pattern 1a may be formed by injection molding at the same time. The transfer pattern 11a may be formed by machining or the like.

  Next, a method for manufacturing an information recording medium substrate using a mold according to another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a manufacturing process of an information recording medium substrate using a mold according to another embodiment of the present invention, and FIGS. 4 (A) to 4 (H) are cross-sectional views showing each process. It is. As shown in FIG. 4A, a mold 11 and a glass substrate 12 that is a substrate base material are opposed to each other, and a transfer pattern 11a of the mold 1 is a glass substrate that is a substrate base material on which a magnetic film 13 is formed. Arranged to face 12 side. For example, CoCrPt or FePt may be used as the magnetic film 13.

  In addition, as a substrate base material, if it is a base material which can form a board | substrate, such as a board | substrate for PM, by providing the surface part which consists of a structural material which has several fine uneven | corrugated shape on the surface, especially if it is a base material Not limited. For example, a quartz substrate or the like may be used instead of the glass substrate. Examples of the glass substrate 12 include a 2.5-inch glass substrate for HDD.

  Next, as shown in FIG. 4B, an imprint material 14 is applied to a portion where a concavo-convex pattern on the glass substrate 12 including the magnetic film 13 is formed. As the imprint material 14, for example, an SOG material may be used. The coating method may be a known coating method, for example, drop coating with a dispenser or the like, spin coating or dip coating, or a wire bar and applicator. You can spread it. If the thermal imprint method is used, for example, a cycloolefin-based resin may be used as the imprint material 14, and if the optical imprint method is used, for example, a photoresist is used as the imprint material 14. That's fine.

  Next, as shown in FIG. 4C, the mold 11 is pressed against the glass substrate 12 on which the imprint material 14 and the magnetic film 13 are laminated with a predetermined pressing force, and the fine structure is transferred to the imprint material 14. Then, the imprint material 14 is dried. By doing so, the imprint material 14 is solidified. Thereby, an uneven pattern is formed on the imprint material 14. There is no restriction | limiting in particular as said drying method, A well-known drying method can be used. For example, although it may be allowed to stand at room temperature, it is preferable to further reduce the pressure, blow, and heat from the viewpoint of faster drying. Further, when heating is performed, it is preferable that the heating temperature does not exceed the boiling point of the solvent of the imprint material 14. By doing so, the imprint material 14 does not boil, and the possibility that bubbles remain inside the imprint material 14 is reduced, so that the occurrence of uneven transfer defects is suppressed. In addition, since the SOG material is used for the imprint material 14, it is solidified by drying. However, when the thermal imprint method is used, the mold 11 is pressed against the imprint material 14 softened by heating and then cooled. Therefore, the imprint material 14 needs to be solidified. Moreover, when using the optical imprint method, it is necessary to solidify the imprint material 14 by irradiating light after pressing the mold 11 against the imprint material 14. Thereby, an uneven pattern is formed on the imprint material 14.

  Next, as shown in FIG. 4D, the mold 11, the imprint material 14, the magnetic film 13, and the glass substrate 12 that are united by pressing the mold 11 are immersed in the liquid 15. Here, the liquid 15 which is a dipping substance to be dipped may be water, for example. By using water as the dipping substance, the dipping substance can be easily obtained, and the versatility is achieved. In addition, the liquid 15 which is the substance for immersion is not limited to water, and is a liquid under a condition in which the imprint material 14 is solidified, and does not erode or break the imprint material 14 and the glass substrate 12. Any substance having any of the above may be used.

  Next, as illustrated in FIG. 4E, the mold 11 is released from the imprint material 14 in a state where the mold 11, the imprint material 14, the magnetic film 13, and the glass substrate 12 are immersed in the liquid 15. . Specifically, the fluid 16 is caused to flow into the through hole 11b. As a result, pressure is applied to the interface between the mold 11 and the imprint material 14, so that the mold 11 is peeled from the imprint material 14. At this time, since the fluid 16 applies pressure to each part of the interface between the mold 11 and the imprint material 14, the mold 11 is peeled off. As the fluid 16, for example, a liquid 15 that is an immersion substance in which the mold 11 and the imprint material 14 are immersed may be used. Further, as the fluid 16, a fluid such as a liquid other than the liquid 15 may be used. At this time, the liquid 15 does not exist only between the imprint material 14 and the mold 11, but the imprint material 14 and the mold 11 are covered with the liquid 15. Therefore, capillary adhesion does not occur, and a large force is not required for mold release, so that mold release can be performed easily. Accordingly, even if the formation position of the through hole 11b is in the vicinity of the inner periphery or the outer periphery, which is a region where the pattern is not formed, a large force is not required in the mold release. The mold can be easily released without damaging the microstructure transferred to the film.

  In addition, since the liquid has a higher viscosity than the gas, it is not easily affected by disturbances during mold release. That is, by releasing the mold in the liquid 15, the liquid 15 penetrates between the mold 11 and the imprint material 14. For example, when mold release is performed by an apparatus, even when the mold 11 and the imprint material 14 vibrate due to noise such as vibration of the apparatus and they collide, the viscosity is higher than that of gas. The shock is reduced by the buffering effect of the liquid 15, and the fine structure transferred to the imprint material 14 is hardly damaged. Further, in addition to the vibration of the apparatus, even when an external force is applied to the mold 11 or the imprint material 14 at the time of mold release due to disturbance such as wind, the fine structure is similarly damaged by the buffering effect of the liquid 15. There is little to be done.

  Next, as shown in FIG. 4F, the magnetic film 13 is exposed by dry-etching the imprint material 14 in which the fine structure is formed.

  Next, as shown in FIG. 4G, a fine structure is formed in the magnetic film 13 by etching the magnetic film 13 by dry etching using the imprint material 14 remaining on the magnetic film 13 as a mask. .

  Next, as shown in FIG. 4 (H), the imprint material 14 is removed, and the information recording medium substrate 17 in which the uneven pattern 13a is formed on the magnetic film 13 on the surface is manufactured.

  As described above, in the embodiment and other embodiments of the present invention, when the molds 1 and 11 are released from the imprint materials 3 and 14, these are converted into the immersion substances that are the liquids 4 and 15. Release in the immersed state. Therefore, capillary adhesion does not occur, and the mold can be easily released without using a large force. Further, since the viscosity of the liquid is higher than that of the gas, the liquid is less susceptible to disturbance during the release than in the case where the release is performed in the atmosphere. Specifically, when the mold release is performed in the apparatus, there is a possibility that the fine structure may be damaged during the mold release due to the vibration of the apparatus, but the imprint materials 3 and 14 and the molds 1 and 11 are around. Are covered with the liquids 4 and 15, the micro structure is hardly damaged by the buffering effect of the liquids. Further, it is hardly affected by other disturbances such as wind, and the microstructure is hardly damaged at the time of mold release.

  In the above manufacturing process, if at least the mold release process (FIGS. 2E and 4E) is performed in a state where the imprint materials 3 and 14 and the molds 1 and 11 are immersed in the liquids 4 and 15, respectively. The other steps may be performed either in a state of being immersed in the liquids 4 and 15 or in a state of not being immersed.

  Further, the molds 1 and 11 may be made of a material that is dissolved by a dipping substance that is the liquids 4 and 15. For example, when the immersion material that is the liquid 4 or 15 is water, the molds 1 and 11 may be made of polyvinyl alcohol (PVA). Further, for example, when the immersion material that is the liquids 4 and 15 is acetone, the molds 1 and 11 may be made of polycarbonate. In this way, when the molds 1 and 11 and the imprint materials 3 and 14 are immersed in the dipping substance that is the liquid 4 and 15, the molds 1 and 11 are dissolved, A gap is formed between the imprint materials 3 and 14, and the liquids 4 and 15 penetrate into the gap, and the mold release can be easily performed. Moreover, it is not necessary for the molds 1 and 11 to be completely dissolved by immersion, and it is sufficient that the surface is dissolved. For example, when the thickness of the molds 1 and 11 is 1 mm and the structural height of the PM is 50 nm, the liquid 4 or 15 easily penetrates. Note that it is necessary that the dipping substance as the liquids 4 and 15 does not dissolve the imprint materials 3 and 14, the glass substrates 2 and 12, and the magnetic film 13.

  Specific examples (Examples 1, 2, and 3) in which information recording medium substrates were actually manufactured by the method of manufacturing an information recording medium substrate according to the above-described embodiment of the present invention and other embodiments, and the surface shapes of the substrates were evaluated. ). Further, an example (Comparative Examples 1 and 2) in which an information recording medium substrate is actually produced by a method for manufacturing an information recording medium substrate according to a conventional example and the surface shape thereof is evaluated will be described.

Example 1
Example 1 will be described with reference to FIGS. 1 and 2. In Example 1, first, a mold 1 shown in FIG. 1 in which a fine structure was formed by injection molding using polymethylpentene resin was used. The mold 1 has a donut shape in which a through hole with an inner diameter of 20 mm is formed at the center of a disk with an outer diameter of 65 mm. The fine pattern 1a for transfer was formed on one side of the mold 1 and formed in a region having a radius of 10 mm or more from the center. The transfer pattern 1a was also formed by injection molding. Here, the specific shape of the mold 1 used in Example 1 will be described with reference to FIG. FIG. 5 is a diagram for explaining the shape of the mold used in Example 1, FIG. 5 (A) is a plan view of the mold, and FIG. 5 (B) is a range A of FIG. 5 (A). 5C is an enlarged view, and FIG. 5C is a cross-sectional view taken along line BB in FIG. 5B. As shown in FIG. 5A, the mold 1 has a donut shape in which a through hole having an inner diameter of 20 mm is formed at the center of a disk having an outer diameter of 65 mm. Although a concentric circle is indicated by a broken line in FIG. 5A, this broken line is a virtual line. In the mold 1, a circular hole having a center is formed on the concentric circle indicated by the broken line as described above. Then, as shown in FIG. 5B which is an enlarged view of the range A of the mold 1, a circular hole 1 c having a diameter of 50 nm centered on a virtual concentric circle indicated by a broken line is formed in the mold 1. Yes. The interval between the concentric circles indicated by broken lines is 100 nm, and the pitch between the circular holes 1c formed adjacent to each other on the same concentric circle is 100 nm. Moreover, as shown to FIG. 5 (C) which is a BB arrow sectional drawing, the depth of each circular hole 1c is 50 nm.

  A 2.5-inch glass substrate 2 for HDD (outer diameter 65 mm, inner diameter 20 mm) is prepared, and the mold 1 and the glass substrate 2 are arranged on the glass substrate 2 side so that the transfer pattern 1a faces (FIG. 2A )reference). Then, 100 microliters of a solution of OCD T-12 900-V (manufactured by Tokyo Ohka Kogyo Co., Ltd.), which is an SOG material, was applied as an imprint material 3 on the glass substrate 2 with a dispenser (see FIG. 2B). ). The imprint material 3 is applied to a location corresponding to the transfer pattern 1 a on the glass substrate 2. Thereafter, the imprint material 3 was dried and solidified in a state where the glass substrate 2 was pressed at 1 MPa with the mold 1 to form a fine structure (see FIG. 2C). After the imprint material 3 was solidified, the glass substrate 2, the imprint material 3, and the mold 1 were immersed in a liquid 4 that is pure water (see FIG. 2D). And in the liquid 4, the pin module 5 was inserted in the interface of the imprint material 3 and the mold 1, and the mold 1 was released (refer FIG.2 (E)). In this manner, ten substrates on which a fine structure was formed were produced, and the transferred fine structure was observed for each substrate. As the observation method, the surface shape of the entire surface of the substrate was observed with an interferometer, and the microstructure of a region of about 10 μm × 10 μm was observed with a scanning electron microscope (SEM) and a region of 2 μm × 2 μm was observed with an atomic force microscope (AFM). As a result, in all the ten substrates, no defect such as destruction of the fine structure was found in the observation region in any of the interferometer, SEM, and AFM.

  Finally, a magnetic film 6 was formed on the imprint material 3 of the produced substrate to obtain a patterned media hard disk drive substrate (information recording medium substrate 7) (see FIG. 2F).

(Example 2)
Example 2 will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, first, a mold 11 shown in FIG. 3 in which a microstructure was formed by injection molding using a polycarbonate resin was used. The mold 11 has a disk shape with an outer diameter of 65 mm, and four circular through holes 11b with a diameter of 5 mm are formed so as to be symmetric four times from the center to a position having a radius of 21 mm. Further, the transfer pattern 11a having a fine structure was formed on one surface of one mold 11 and formed in a region having a radius of 10 mm or more from the center. The transfer pattern 11a was also formed by injection molding. The mold 11 used in Example 2 is also formed with the circular holes shown in FIGS. 5B and 5C with the same shape and arrangement as the mold 1 of Example 1.

  Next, what prepared the magnetic film 13 on the main surface of the 2.5-inch glass substrate 12 (outer diameter 65 mm, inner diameter 20 mm) for HDD was prepared (see FIG. 4A). Further, the mold 11 and the glass substrate 12 are arranged on the glass substrate 12 side so that the transfer pattern 11a faces. Then, 100 microliters of a solution of PAK-02 (manufactured by Toyo Gosei Co., Ltd.), which is a photocurable resin, was applied as an imprint material 14 on the glass substrate 12 including the magnetic film 13 with a dispenser (FIG. 4 ( B)). Note that the imprint material 14 is applied to portions on the magnetic film 13 corresponding to the transfer pattern 11a. Thereafter, the imprint material 14 is irradiated with light in a state where the imprint material 14 and the glass substrate 12 including the magnetic film 13 are pressed by the mold 11, and the imprint material 14 is solidified to form a fine structure (FIG. 4 ( C)). After the imprint material 14 was solidified, the glass substrate 12, the magnetic film 13, the imprint material 14, and the mold 11 were immersed in a liquid 15 that is pure water (see FIG. 4D). In the liquid 15, release was performed by applying pressure to the liquid 15 (fluid 16), which is pure water, from the through-hole 11 b (see FIG. 4E). In this manner, ten substrates on which a fine structure was formed were produced, and the transferred fine structure was observed for each substrate. As the observation method, the surface shape of the entire surface of the substrate was observed with an interferometer, and the microstructure of a region of about 10 μm × 10 μm was observed with a scanning electron microscope (SEM) and a region of 2 μm × 2 μm was observed with an atomic force microscope (AFM). As a result, in all the ten substrates, no defect such as destruction of the fine structure was found in the observation region in any of the interferometer, SEM, and AFM.

  After that, the fine structure layer of the imprint material 14 that is a photocurable resin was etched by dry etching until the magnetic film 13 was exposed on the bottom surface of the fine structure layer (see FIG. 4F). Then, the magnetic film 13 is etched by dry etching using the remaining imprint material 14 as a photocurable resin as a mask (see FIG. 4G). Finally, the imprint material 14 as a photocurable resin is removed. The information recording medium substrate 17 having the concavo-convex pattern 13a formed on the magnetic film 13 on the surface was removed by dry etching (see FIG. 4H).

(Example 3)
Embodiment 3 will be described with reference to FIGS. 1 and 2. In Example 3, first, a mold 1 shown in FIG. 1 in which a microstructure was formed by injection molding using a polycarbonate resin was used. The mold 1 has a donut shape in which a through hole with an inner diameter of 20 mm is formed at the center of a disk with an outer diameter of 65 mm. The fine pattern 1a for transfer was formed on one side of the mold 1 and formed in a region having a radius of 10 mm or more from the center. The transfer pattern 1a was also formed by injection molding. In addition, the specific shape of the mold 1 used in Example 3 is the same shape as the mold 1 shown in FIGS. 5A to 5C used in Example 1.

  Next, a 2.5-inch glass substrate 2 for HDD (outer diameter 65 mm, inner diameter 20 mm) is prepared, and the mold 1 and the glass substrate 2 are arranged on the glass substrate 2 side so that the transfer pattern 1a faces (FIG. 2). (See (A)). Then, a solution of OCD T-7 8000-T (manufactured by Tokyo Ohka Kogyo Co., Ltd.) which is an SOG material as the imprint material 3 was applied on the glass substrate 2 with a dispenser of 100 microliters (FIG. 2B). reference). The imprint material 3 is applied to a location corresponding to the transfer pattern 1 a on the glass substrate 2. Thereafter, the imprint material 3 was dried and solidified in a state where the glass substrate 2 was pressed at 1 MPa with the mold 1 to form a fine structure (see FIG. 2C). After the imprint material 3 was solidified, the glass substrate 2, the imprint material 3, and the mold 1 were immersed in a liquid 4 that was acetone (see FIG. 2D). Since polycarbonate has the property of being dissolved by acetone, the mold 1 starts to be dissolved when immersed in the liquid 4. In the liquid 4, the pin module 5 was inserted into the boundary surface between the imprint material 3 and the mold 1, and the mold 1 was released (see FIG. 2E). In addition, since the mold 1 starts to melt | dissolve, the liquid 4 is easily filled between the mold 1 and the imprint material 3, and destruction of a fine structure is suppressed. In this manner, ten substrates on which a fine structure was formed were produced, and the transferred fine structure was observed for each substrate. As the observation method, the surface shape of the entire surface of the substrate was observed with an interferometer, and the microstructure of a region of about 10 μm × 10 μm was observed with a scanning electron microscope (SEM) and a region of 2 μm × 2 μm was observed with an atomic force microscope (AFM). As a result, in all the ten substrates, no defect such as destruction of the fine structure was found in the observation region in any of the interferometer, SEM, and AFM.

  Finally, a magnetic film 6 was formed on the imprint material 3 of the produced substrate to obtain a patterned media hard disk drive substrate (information recording medium substrate 7) (see FIG. 2F).

(Comparative Example 1)
Comparative Example 1 produced by a conventional method for producing an information recording medium substrate will be described. In Comparative Example 1, an information recording medium substrate was produced in substantially the same manner as the information recording medium substrate manufacturing method of Example 1. The difference between the manufacturing method of Comparative Example 1 and the manufacturing method of Example 1 is that the mold release is performed in the air instead of in the liquid, and the other manufacturing methods are substantially the same. In this manner, ten substrates on which a fine structure was formed were produced, and the fine structure was observed for each substrate. As the observation method, the surface shape of the entire surface of the substrate was observed with an interferometer, and the microstructure of a region of about 10 μm × 10 μm was observed with a scanning electron microscope (SEM) and a region of 2 μm × 2 μm was observed with an atomic force microscope (AFM). As a result, in 7 out of 10 sheets, defects such as microstructural breakdown were not found by interferometer, SEM, and AFM, but in the remaining 3 sheets, microstructural breakdown was partially observed.

(Comparative Example 2)
Comparative Example 2 produced by a conventional method for producing an information recording medium substrate will be described. In Comparative Example 2, an information recording medium substrate was produced in substantially the same manner as the information recording medium substrate manufacturing method of Example 2. The difference between the manufacturing method of Comparative Example 2 and the manufacturing method of Example 2 is that the mold release is performed in the air, not in the liquid, and the other manufacturing methods are substantially the same. When releasing the mold, air was introduced into the through hole of the mold. In this manner, ten substrates on which a fine structure was formed were produced, and the fine structure was observed for each substrate. As the observation method, the surface shape of the entire surface of the substrate was observed with an interferometer, and a fine structure of about 10 μm × 10 μm region was observed with a scanning electron microscope (SEM) and 2 μm × 2 μm region was observed with an atomic force microscope (AFM). As a result, no defects such as fine structure destruction were found in 8 out of 10 sheets by an interferometer, SEM, and AFM, but partial destruction of the fine structure was observed in the remaining 2 sheets.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

1A and 1B are a plan view and a cross-sectional view illustrating a configuration of a mold according to the present embodiment, in which FIG. 1A is a plan view illustrating a configuration of a mold, and FIG. 1B is a cross-sectional view illustrating a configuration of a mold. . FIGS. 2A to 2F are cross-sectional views showing the steps of manufacturing the information recording medium substrate using the mold according to the present embodiment. FIGS. FIG. 3A is a plan view showing a configuration of a mold according to another embodiment of the present invention, and FIG. 3B is a plan view showing a configuration of the mold, and FIG. 3B is a diagram showing a configuration of the mold. It is sectional drawing. It is sectional drawing which shows the manufacturing process of the information recording medium board | substrate using the mold which concerns on other embodiment of this invention, Comprising: FIG. 4 (A)-FIG. 4 (H) are sectional drawings which show each process. It is a figure for demonstrating the shape of the mold used in Example 1, Comprising: FIG. 5 (A) is a top view of a mold, FIG.5 (B) is an enlarged view of the range A of FIG. 5 (A). FIG. 5C is a cross-sectional view taken along line BB in FIG. 5B. It is a figure for demonstrating capillary adhesion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Mold 1a, 11a Transfer pattern 1c Circular hole 11b Through hole 2, 12 Glass substrate 3, 14 Imprint material 4, 15 Liquid 5 Pin module 6, 13 Magnetic film 6a, 13a Uneven pattern 7, 17 Information recording medium Substrate 16 Fluid 101, 102 Substrate 103 Liquid

Claims (4)

A step of pressing a mold having a concavo-convex structure onto the molding material formed on the substrate substrate to transfer the concavo-convex structure to the molding material;
Solidifying the molding material in a state where the mold is pressed;
A step of releasing the mold from the solidified molding material,
The step of releasing the mold is a method for manufacturing an information recording medium substrate, wherein the molding material and the mold are immersed in a dipping substance that is liquid when the molding material is solidified.   The method for manufacturing an information recording medium substrate according to claim 1, wherein the immersion substance is a substance that does not erode the molding material and the base substrate. The immersion material has a property of dissolving the mold,
The method of manufacturing an information recording medium substrate according to claim 1, wherein in the step of releasing the mold, at least a part of the mold is dissolved by the dipping substance.   The method for manufacturing an information recording medium substrate according to claim 1, wherein the dipping substance is water.

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