JP4058444B2 - Stamper, imprint method, and information recording medium manufacturing method - Google Patents

Description

  The present invention relates to a stamper used at the time of manufacturing an information recording medium, an imprint method in which a stamper is pressed against a resin layer formed on the surface of a substrate to transfer the uneven shape, and information recording using the uneven pattern transferred to the resin layer The present invention relates to an information recording medium manufacturing method for manufacturing a medium.

  As a method for forming a fine concavo-convex pattern (resist pattern) on a resist layer (resin layer) formed on the surface of a substrate in a process of manufacturing an information recording medium or the like, a photolithography method has been conventionally known. In this photolithography method, the resist layer formed on the substrate is irradiated with light to form an exposure pattern, and then the resist layer is developed to form an uneven pattern on the substrate. In recent years, as a technique for forming a finer pattern, an electron beam lithography method has been developed in which a nanometer-sized pattern is drawn by irradiating an electron beam instead of light to form a concavo-convex pattern. Yes. However, this electron beam lithography method has a problem that mass production is difficult because it takes a long time to draw a pattern on the resist layer.

  As a technology to solve this problem, a stamper with a nanometer-size uneven pattern is pressed against the resin layer on the substrate to transfer the uneven shape of the stamper to the resin layer. A nanoimprint lithography method for forming a concavo-convex pattern (an imprint method for forming a nanometer-sized concavo-convex pattern: hereinafter, also referred to as “imprint method”) is disclosed in US Pat. No. 5,772,905. In this imprint method, first, FIG. As shown in FIG. 1A, a stamper 10z (hereinafter referred to as US Pat. No. 5,772,905) in which a concavo-convex pattern having a nanometer size (for example, a minimum width of about 25 nm) is formed on the transfer surface The element is expressed by adding “z” to each symbol). More specifically, a desired pattern is formed on the resin layer formed so as to cover the molding layer 14z formed on the surface of the silicon substrate 12z by using an electron beam lithography apparatus. After the drawing, the thin film 14z is etched by a reactive ion etching apparatus using the resin layer as a mask, thereby forming a concavo-convex pattern having a plurality of features 16z within the thickness of the thin film 14z. Thereby, the stamper 10z is manufactured.

Next, for example, polymethyl methacrylate (PMMA) is spin-coated on the surface of a silicon substrate 18z to form a resin layer (thin film layer) 20z having a thickness of about 55 nm. Then, after heating both the laminated body of the base material 18z and the resin layer 20z, and the stamper 10z so that it may become about 200 degreeC, FIG. As shown to 1B, each convex part 16z of the stamper 10z is pressed against the resin layer 20z on the base material 18z with a pressure of 13.1 MPa (133.6 kgf / cm ² ). Next, after the laminate with the stamper 10z pressed is left to reach room temperature (after cooling), the stamper 10z is peeled from the resin layer 20z. As a result, FIG. As shown in FIG. 1C, each convex portion 16z in the concave / convex pattern of the stamper 10z is transferred to the resin layer 20z to form a plurality of concave portions (regions) 24z, and a nanometer size is formed on the substrate 18z (resin layer 20z). An uneven pattern is formed.
US Pat. No. 5,772,905

  However, the conventional imprint method has the following problems. That is, in this imprinting method, FIG. As shown in 1A and 1B, the height from the bottom surface of the concave portion to the protruding end portion of each convex portion 16z in the concavo-convex pattern is uniform over the entire area, that is, the protruding end portion of each convex portion 16z is substantially flush. The stamper 10z formed so as to become is pressed against the resin layer 20z to form an uneven pattern on the substrate 18z. In this case, the stamper 10z has a length along the direction corresponding to the circumferential direction (rotation direction) of the information recording medium (hereinafter referred to as “circumferential length”) according to the shape of the data track pattern or servo pattern to be formed. And various convex portions 16z having different lengths along the direction corresponding to the radial direction of the information recording medium (hereinafter also referred to as “radial length”). However, in the conventional imprinting method, since the concave / convex pattern is pressed against the resin layer 20z with a substantially uniform pressing force over the entire area of the stamper 10z, for example, it is long in the radial direction and relatively long in the circumferential direction. It is difficult to sufficiently push the portion where the convex portion 16z is formed into the resin layer 20z.

  Specifically, as shown in FIG. 28, for example, each convex portion 16z for forming a data track pattern in an information recording medium has a relatively long circumferential length, but its radial length L11. However, it is relatively short in the entire area from the inner circumference side to the outer circumference side of the information recording medium. Accordingly, in the data track pattern formation region in which the convex portion 16z having a relatively short radial length L11 is formed, the PMMA is directed toward the concave portion around each convex portion 16z when the convex portion 16z is pushed. As a result of being able to move smoothly (the resin material forming the resin layer 20z), each convex portion 16z can be pushed deeply into the resin layer 20z. As a result, in the data track pattern formation region, a concavo-convex pattern with a sufficiently thin residue T11 between the protruding end of each convex portion 16z and the base material 18z (the bottom portion of the concave portion 24z) is formed on the base material 18z. be able to.

  On the other hand, as shown in FIG. 29, for example, each convex portion 16z for forming a servo pattern preamble pattern or sector address pattern in an information recording medium generally has a radial length of information. The recording medium is relatively long corresponding to the length from the inner periphery to the outer periphery, and the circumferential length L12 is also relatively longer at the portion corresponding to the outer periphery of the information recording medium. Therefore, in the servo pattern formation region (in this example, the outer peripheral portion of the preamble pattern formation region and the sector address pattern formation region) where the convex portion 16z having a relatively long circumferential length L12 is formed, each convex portion 16z is When it is pushed in, it is difficult to smoothly move the PMMA into the concave portions around each convex portion 16z, so that it becomes difficult to push each convex portion 16z into the resin layer 20z sufficiently deeply. As a result, in the outer peripheral portion in the region where the servo pattern (preamble pattern or the like) is to be formed, it is difficult to sufficiently reduce the thickness T12 of the residue between the protruding end portion of each convex portion 16z and the base material 18z. ing.

  Further, for example, a convex portion 16z for forming a burst pattern in which a unit burst region of a servo pattern in an information recording medium is formed by a convex portion (a convex portion 16z for forming a concave portion between unit burst regions in the burst pattern). ) Is defined so that the circumferential length between the concave portions corresponding to the unit burst region gradually increases from the inner peripheral portion toward the outer peripheral portion. Furthermore, each convex part 16z (each convex part 16z for forming the unit burst area in the burst pattern) for forming a burst pattern in which the unit burst area of the servo pattern in the information recording medium is constituted by a concave part, The circumferential length is defined so that the convex portion 16z on the outer peripheral portion gradually becomes longer from the inner peripheral portion toward the outer peripheral portion than the convex portion 16z on the inner peripheral portion. Therefore, in the servo pattern formation region (in this example, the outer peripheral portion in the burst pattern formation region) where the convex portion 16z having a relatively long circumferential length is formed, each convex portion is formed when the convex portion 16z is pushed. Since it is difficult to smoothly move the PMMA into the recesses around 16z, it is difficult to push each protrusion 16z sufficiently deep into the resin layer 20z. As a result, it is difficult to sufficiently reduce the thickness of the residue between the protruding end of each convex portion 16z and the base material 18z at the outer peripheral portion in the region where the servo pattern (burst pattern) is to be formed. . Further, the convex portion 16z for forming a burst pattern in which the unit burst region is formed of convex portions has a large area ratio with respect to the concave portion in the burst pattern forming region, so that the inner circumferential length is relatively short. There is a risk that it may be difficult to push the resin layer sufficiently deep into the resin layer.

  In this case, when an information recording medium is manufactured using the concavo-convex pattern formed on the base material 18z, it is necessary to remove the residue on the bottom surface of each concave portion 24z in the concavo-convex pattern from the base material 18z by an etching process or the like. . Therefore, when a concavo-convex pattern is formed on the base material 18z by a conventional imprint method, for example, the thickness T12 at a portion where the convex portion 16z having a long circumferential length L12 is pushed (the outer peripheral portion in the formation region of the preamble pattern or the like). There is a problem that it takes a long time to remove the residue. Further, as described above, for example, the thickness T11 of the residue in the portion (data track pattern formation region) where the convex portion 16z having a short radial length L11 is pushed is sufficiently thinner than the thickness T12. Therefore, when the etching process is performed for a sufficient time so that the residue of thickness T12 can be surely removed, the removal of residue of thickness T11 is completed before the removal of residue of thickness T12 is completed. As a result, at the portion where the residue of thickness T11 has been removed (the recess 24z having a length in the radial direction of length L11), the inner wall of the recess 24z is eroded by continuing to be etched until the removal of the residue of thickness T12 is completed. As a result, the length in the radial direction (opening length) of the recess 24z is increased. For this reason, in the conventional imprint method, when forming the concave / convex pattern on the substrate 18z, the length (opening length) of each concave portion 24z after removing the residue (after the etching process) is formed in a desired width. There is a problem that it is difficult to do.

  The present invention has been made in view of such problems, and mainly provides a stamper, an imprint method, and an information recording medium manufacturing method capable of forming a concave / convex pattern having a concave portion having a desired opening length with high accuracy. Objective.

In order to achieve the above object, the stamper according to the present invention has a stamper-side concavo-convex pattern formed on the stamper-side concavo-convex pattern so that an information recording medium in which a data track pattern and a servo pattern are formed as a concavo-convex pattern can be manufactured. And a plurality of types of convex portions having different heights from the reference surface to the projecting end portion defined between the back surface and the back surface, and among the convex portions formed in a region corresponding to the data track pattern The second convex portion having a height that is at least partially higher than the first convex portion having the highest height is formed in a region corresponding to the servo pattern, and the second convex portion is the information. The length of the direction corresponding to the circumferential direction of the information recording medium is continuously formed along the direction corresponding to the radial direction of the recording medium, and the length of the first convex portion A third convex portion formed so that the height is higher than the first convex portion in a portion longer than the length of the direction corresponding to the direction, and a unit burst region in the burst pattern of the servo patterns And a fourth convex portion formed so that the height of at least a portion thereof is higher than that of the first convex portion.

Contact name is "surface of the stamper" herein, "the bottom surface of the recess of the stamper side convex pattern", i.e., meaning "forming surface of the stamper side convex pattern". In this case, when the bottom surface of each recess in the stamper-side concavo-convex pattern is not flush, the bottom surface of one of the recesses (as an example, the bottom surface closest to the back surface of the stamper among the bottom surfaces of each recess) The surface. Further , “between the front surface and the back surface” in the present invention includes both “the front surface of the stamper” and “the back surface of the stamper”. Further, the "reference surface" herein, it means any surface which is defined between the surface of the stamper to the back. In addition, the “length in the direction corresponding to the circumferential direction (the convex portion)” in this specification means “the distance along the circumferential direction between the side wall surfaces facing each other in one convex portion”. Further, the "direction corresponding to the radial direction (the convex portion) length" herein, that means the "distance along the radial direction between the side wall surfaces facing each other in one of the convex portions". In addition, the “unit burst region” in the present specification refers to a plurality of convex portions or a plurality of convex portions of a substantially parallelogram (parallelogram shape) or a substantially elliptic shape (including a circle) arranged in the circumferential direction in the information recording medium. Each of the concave regions is referred to.

  In the stamper according to the present invention, the fourth convex portion is formed so that the height in the entire region is higher than that of the first convex portion.

The stamper according to the present invention is formed with a stamper-side concavo-convex pattern so that an information recording medium in which a data track pattern and a servo pattern are formed as a concavo-convex pattern can be manufactured. A plurality of types of convex portions having different heights from the reference surface defined between them to the protruding end portion are formed, and the height among the convex portions formed in the region corresponding to the data track pattern A second convex portion having a height higher than that of the first convex portion having the highest height is formed in a region corresponding to the servo pattern, and the second convex portion has a diameter of the information recording medium. The length of the direction corresponding to the circumferential direction of the information recording medium corresponds to the radial direction of the first convex portion. A third convex part formed so that the height is higher than the first convex part at a portion longer than the length of the direction, and the unit burst area corresponding to the unit burst region in the burst pattern of the servo patterns Each of the convex portions includes a fifth convex portion formed so that the height is higher than that of the first convex portion.

Further, the imprint method according to the present invention includes a stamper pressing process for pressing the stamper-side uneven pattern in any one of the above stampers onto a resin layer formed by applying a resin material to the surface of a substrate, and from the resin layer A stamper peeling process for peeling the stamper is performed in this order, and the uneven shape of the stamper side uneven pattern is transferred to the resin layer to form an etching process mask .

In addition, the information recording medium manufacturing method according to the present invention manufactures an information recording medium using the concavo-convex pattern transferred to the resin layer by the imprint method as a mask for etching treatment .

According to the stamper and the imprint method using the stamper according to the present invention, at least a part of the first convex portion having the highest height among the convex portions formed in the region corresponding to the data track pattern. The stamper side uneven pattern is formed by forming the second convex portion having a high height in the region corresponding to the servo pattern, so that the entire area of the stamper (formation of the data track pattern formation region and the servo pattern is formed during imprinting. When the stamper is pressed against the resin layer with a uniform pressing force over the area), each protrusion in the servo pattern formation area where there are many protrusions that are difficult to be pressed into the resin layer is pressed deeply into the resin layer. Can do. Therefore, as a result of the respective convex portions in the forming region of the projections and the servo pattern in the form Naruryo region of the data track pattern in the same extent to the resin layer, moreover it can be pressed sufficiently, the residue on the substrate Can be made uniform over the entire area of the substrate. Therefore, since the time required for removing the residue can be substantially the same over the entire area, the side wall surface of each recess in the uneven pattern transferred to the resin layer in the region corresponding to the data track pattern region It is possible to avoid a situation where each recess is formed to have an unintended wide opening width due to erosion. As a result, a concave / convex pattern having a concave portion having a desired opening width can be formed with high accuracy over both the data track pattern region and the servo pattern region. In addition, by manufacturing an information recording medium using a concavo-convex pattern formed with high accuracy, it is possible to manufacture an information recording medium in which recording / reproducing errors are unlikely to occur.

  Further, according to the stamper according to the present invention, the length of the direction corresponding to the circumferential direction of the information recording medium is longer than the length of the first protrusion at a portion longer than the length of the direction corresponding to the radial direction of the first protrusion. Since the third convex portion is formed so that the height is increased, the circumferential length of the outer peripheral portion of the third convex portion, such as a convex portion for forming a preamble pattern or a convex portion for forming a sector address pattern, is increased. The third protrusions whose length is longer than the radial length of the first protrusions for forming the data track pattern are the same as the first protrusions for forming the data track pattern, and to a sufficient depth. It can be pushed into the resin layer. Therefore, the residue thickness in the region corresponding to the data track pattern region (data track pattern formation region) and the residue thickness in the region corresponding to the servo pattern region (servo pattern formation region) are made substantially uniform. be able to.

  Furthermore, according to the stamper according to the present invention, the fourth convex portion for forming the burst pattern is formed by forming the fourth convex portion so that the height of at least a portion is higher than the first convex portion. The outer peripheral portion that is difficult to be pushed into the resin layer during the imprinting process can be reliably pushed into the resin layer to the same extent as the first convex portion for forming the data track pattern and to a sufficient depth. Therefore, the residue thickness in the region corresponding to the data track pattern region (data track pattern formation region) and the residue thickness in the region corresponding to the burst pattern region (burst pattern formation region) are made substantially uniform. be able to.

  Further, according to the stamper according to the present invention, the fourth convex portion is formed so that the height in the entire region is higher than that of the first convex portion, so that the resin layer has a large area ratio to the concave portion. On the other hand, the fourth convex part for forming the burst pattern which is difficult to be pushed in can be pushed into the resin layer to a sufficient depth from the inner peripheral part to the entire outer peripheral part.

In addition, according to the stamper according to the present invention, the fifth protrusion is formed so that the height is higher than that of the first protrusion. Similar to the convex portions and the fourth convex portions, it can be pushed into the resin layer to the same extent as each convex portion in the data track pattern formation region and to a sufficient depth.

Further, according to the information recording medium manufacturing method of the present invention, the servo signal can be reliably obtained by manufacturing the information recording medium using the uneven pattern transferred to the resin layer by the imprint method as a mask for the etching process. Therefore, the magnetic head can be accurately tracked with respect to the desired track, and the recording data can be accurately recorded on the data recording track and the recording data can be accurately read from the data recording track. A recording medium can be manufactured.

  The best mode of a stamper, an imprint method, and an information recording medium manufacturing method according to the present invention will be described below with reference to the accompanying drawings.

  First, a configuration of an imprint apparatus 100 that manufactures an information recording medium using a stamper according to the present invention will be described with reference to the drawings.

  An imprint apparatus 100 shown in FIG. 1 includes a press machine 110 and a control unit 120. When the information recording medium 1 shown in FIGS. 2 and 3 is manufactured according to the imprint method according to the present invention, the intermediate 10 (see FIG. 4). ) Is pressed against the stamper 20 (see FIG. 5) to form an uneven pattern 36 (see FIG. 23). In this case, the information recording medium 1 is a discrete track type magnetic recording medium, and as shown in FIG. 2, a servo pattern area As is provided between each data track pattern area At, and the data track pattern area At and The servo pattern areas As are defined so as to be alternately arranged in the rotation direction of the information recording medium 1 (circumferential direction: direction of arrow R). Further, as shown in FIG. 3, the data track pattern area At includes a plurality of convex portions 5a each having a plurality of convex portions 5a. In addition, the servo pattern region As is formed with a concavo-convex pattern 5 having a plurality of concave portions 5b, and various servo patterns for tracking servo control have a plurality of convex portions 5a and a plurality of concave portions 5b. It is formed by (uneven pattern 5s). In FIG. 5 and FIG. 5, in order to facilitate understanding of the present invention, the length of each convex portion and each concave portion is illustrated with a length different from the actual length. Further, in this specification, an area sandwiched between two data track pattern areas At aligned in the rotation direction (from one end of the data track pattern area At to another data track from the downstream side with respect to the rotation direction). A region between the end of the pattern region At and the upstream side with respect to the rotation direction) is defined as a servo pattern region As.

  As shown in FIG. 4, the intermediate body 10 includes, as an example, a magnetic layer 12, a metal layer 13, and a resin on a disk-shaped substrate 11 formed in a disk shape with alumina, silicon, glass, ceramic, or the like. The layer 14 is configured by being stacked (formed) in this order. In this case, actually, there are various functional layers such as a soft magnetic layer and an orientation layer between the disk-shaped substrate 11 and the magnetic layer 12. The description and illustration are omitted. In this example, the disk-shaped substrate 11, the magnetic layer 12, and the metal layer 13 constitute the substrate in the present invention. Moreover, about the resin material which forms the resin layer 14, since the uneven | corrugated shape of the uneven | corrugated pattern 36 formed when the stamper 20 is peeled becomes favorable so that it may mention later, as an example, polystyrene-type resin, methacrylic resin ( PMMA), polystyrene, phenolic resin and novolac resin are preferably used. In this case, in this intermediate body 10, as an example, the resin layer 14 is formed with a novolac resin so that the thickness is in the range of 40 nm to 100 nm (for example, 70 nm).

  On the other hand, as shown in FIG. 5, the stamper (mold) 20 is formed in a disc shape having a thickness of about 300 μm by laminating an electrode film 21 and a nickel layer 22, and its back surface (upper surface in the figure) is flat. The concave / convex pattern 35 (an example of a stamper side concave / convex pattern in the present invention) for forming the concave / convex pattern 36 on the resin layer 14 of the intermediate 10 Bottom surface: formed on the bottom surface in FIG. In addition, as will be described later, the surface of the electrode film 21 (the surface of the concavo-convex pattern 35) is coated on the stamper 20 with, for example, a fluorine-based material in order to prevent the resin material from adhering to the stamper 20 when peeled from the resin layer 14. Thus, an adhesion reducing film 23 is formed. The material for forming the adhesion reducing film 23 is not limited to the fluorine-based coating material, and various materials that can reduce the adhesion with the resin layer 14 can be employed. In this case, the concavo-convex pattern 35 of the stamper 20 is formed with the respective convex portions 35a corresponding to the respective concave portions 5b of the concavo-convex pattern 5 (the concavo-convex patterns 5t and 5s) in the information recording medium 1, and Recesses 35b are formed corresponding to the protrusions 5a.

  Specifically, as shown in FIG. 6, the data track in which the concave / convex pattern 35 t for forming the concave / convex pattern 5 t (data track pattern) is formed in the data track pattern area At of the information recording medium 1 is formed on the stamper 20. The data track pattern of the information recording medium 1 includes the pattern formation area Ats and the servo pattern formation area Ass in which the uneven pattern 35s for forming the uneven pattern 5s (servo pattern) is formed in the servo pattern area As of the information recording medium 1. It is defined corresponding to the area At and the servo pattern area As. In FIG. 7 and FIGS. 7 to 9 and 25 to 27 to be referred to later, the formation site of the convex portion 35a is shown by being shaded. Also, in the servo pattern formation region Ass, a preamble pattern formation region Aps in which a concavo-convex pattern 35s for forming a preamble pattern is formed, and an address pattern formation region in which a concavo-convex pattern 35s for forming an address pattern is formed. (Not shown) and a burst pattern forming region Abs in which a concave / convex pattern 35s for forming a burst pattern is defined. Further, in the burst pattern formation area Abs, four areas of areas Ab1s to Ab4s corresponding to the signal areas in the burst pattern of the information recording medium 1 are defined.

  In this case, each protrusion 35a formed in the data track pattern formation area Ats and each protrusion 35a formed in the servo pattern formation area Ass are in accordance with the shape of the data track pattern or servo pattern of the information recording medium 1. The length along the direction corresponding to the radial direction of the information recording medium 1 (hereinafter, the direction corresponding to the radial direction of the information recording medium 1 in the stamper 20 is also referred to as “radial direction”). And the direction corresponding to the circumferential direction (rotation direction) in the information recording medium 1 (hereinafter, the direction corresponding to the circumferential direction of the information recording medium 1 in the stamper 20 is also referred to as “circumferential direction”). The length (hereinafter also referred to as “the length in the circumferential direction”) is defined. Specifically, as shown in FIG. 7, each projection 35 a 1 formed in the data track pattern formation region Ats forms each guard band portion (each recess between tracks) of the data track pattern in the information recording medium 1. The protrusion 35a is formed continuously along the direction corresponding to the circumferential direction (rotation direction) of the information recording medium 1 and is formed in a belt shape that is long in the circumferential direction. The convex portion 35a1 is an example of the first convex portion in the present invention, and the length in the circumferential direction is defined corresponding to the length in the circumferential direction of the data track pattern area At in the information recording medium 1. Yes. Also, as shown in FIG. 12, the convex portion 35a1 (“data track pattern convex portion” in FIG. 12) extends from the region corresponding to the inner peripheral portion Ai of the information recording medium 1 to the region corresponding to the outer peripheral portion Ao. In the entire region, the length in the radial direction (length L1 shown in FIG. 7) is, for example, 100 nm. 7 is a concave portion 35b for forming the convex portion 5a for the data recording track in the information recording medium 1. As an example, the radial length of the concave portion 35b1 is the radial direction of the convex portion 35a1. It is defined and formed so as to be approximately equal to the length of.

  Further, as shown in FIG. 8, the convex portion 35a2 formed in the preamble pattern forming region Aps in the servo pattern forming region Ass is a convex portion 35a for forming the concave portion 5b for the preamble pattern in the information recording medium 1. Thus, it is continuously formed along a direction corresponding to the radial direction of the information recording medium 1 and is formed in a strip shape long in the radial direction. The convex portion 35a2 is an example of a third convex portion as the second convex portion in the present invention, and the length in the radial direction is the length from the inner peripheral portion Ai to the outer peripheral portion Ao of the information recording medium 1. It is stipulated correspondingly. Further, as shown in FIG. 12, the convex portion 35a2 ("preamble pattern convex portion (2 bit length)" in FIG. 12) has a circumferential length (length L2 shown in FIG. 8) from the inner peripheral portion. In the region corresponding to the inner peripheral portion Ai of the information recording medium 1 (as an example, a position at a distance of 5.0 mm from the center), the length in the circumferential direction is defined so as to become gradually longer toward the outer peripheral portion. L2 is formed to be 56 nm as an example, and in the region corresponding to the outer peripheral portion Ao of the information recording medium 1 (for example, a position at a distance of 13.0 mm from the center), the circumferential length L2 Is formed to be 147 nm as an example. Note that the concave portion 35b2 shown in FIG. 8 is a concave portion 35b for forming the convex portion 5a for the preamble pattern in the information recording medium 1, and as an example, the convex portion 35a2 whose circumferential length is the same radial position. Are defined so as to be substantially equal to the circumferential length. Further, “2 bit length” in FIG. 12 refers to a circumferential length recognized as a 2 bit signal in an address pattern or the like at the same radial position. Similarly, “8-bit length” refers to a circumferential length recognized as an 8-bit signal in an address pattern or the like at the same radial position.

  Further, a convex portion 35a (not shown) formed in the sector address pattern forming region in the servo pattern forming region Ass is a convex portion for forming the concave portion 5b for the sector address pattern in the information recording medium 1. In the same manner as the convex portion 35a2 for forming the concave portion 5b for the preamble pattern described above, it is continuously formed along the direction corresponding to the radial direction of the information recording medium 1 and formed in a strip shape long in the radial direction. ing. Therefore, in the following description, the convex portion 35a for forming the sector address pattern is described with the same reference numeral as the convex portion 35a2 for forming the preamble pattern. The convex portion 35a2 is another example of the third convex portion as the second convex portion in the present invention, and the length in the radial direction is from the inner peripheral portion Ai to the outer peripheral portion Ao of the information recording medium 1. It is specified in correspondence with the length of Further, the convex portion 35a2 for forming the sector address pattern is defined such that its circumferential length (length L2 shown in FIG. 8) gradually increases from the inner peripheral portion toward the outer peripheral portion. Specifically, as shown in FIG. 12, the 2-bit long convex portion 35a2 of the convex portions 35a2 is an example in which the circumferential length L2 is an area corresponding to the inner peripheral portion Ai of the information recording medium 1. In the region corresponding to the outer peripheral portion Ao of the information recording medium 1, the circumferential length L2 is 147 nm as an example. Furthermore, the 8-bit long convex portion 35a2 of the convex portions 35a2 for forming the sector address pattern has a circumferential length L2 of 226 nm as an example in an area corresponding to the inner peripheral portion Ai of the information recording medium 1. In addition, in the region corresponding to the outer peripheral portion Ao of the information recording medium 1, the circumferential length L2 is, for example, 587 nm. The concave portion 35b (not shown) formed in the sector address pattern formation region is a concave portion 35b for forming the convex portion 5a for the sector address pattern in the information recording medium 1. As an example, the peripheral portion 35b Similarly to the circumferential length of the convex portion 35a2 for forming the sector address pattern, the length in the direction is defined to be 2 bits or 8 bits.

  Further, as shown in FIG. 9, the convex portion 35a3 formed in the burst pattern forming region Abs (for example, the region Ab1s) in the servo pattern forming region Ass is the fourth convex portion as the second convex portion in the present invention. It is an example of a convex part, Comprising: It is comprised so that the recessed part 5b of the burst pattern in the information recording medium 1 can be formed. In this case, in the burst pattern forming area Abs of the stamper 20, as an example, the information recording medium 1 having a burst pattern in which each unit burst area is formed of a convex portion can be manufactured. A recess 35b3 is formed in a portion corresponding to each unit burst region. Further, as an example, the convex portion 35a3 is formed as one convex portion in the burst pattern forming region Abs so as to surround the plurality of concave portions 35b3 in the regions Ab1s to Ab4s. Furthermore, as shown in FIG. 12, the convex portion 35a3 (the “burst pattern convex portion” in FIG. 12) is a circumferential length between two concave portions 35b3 adjacent in the circumferential direction in each of the regions Ab1s to Ab4s. (Length L3 shown in FIG. 9) is defined so as to gradually increase from the inner periphery toward the outer periphery, and is formed to be 56 nm in a region corresponding to the inner periphery Ai of the information recording medium 1. At the same time, it is formed to be 147 nm in a region corresponding to the outer peripheral portion Ao of the information recording medium 1. As an example, the circumferential length of each concave portion 35b3 is defined to be substantially equal to the circumferential length (length L3) between the concave portions 35b3 in the convex portion 35a3 at the same radial position. .

  Furthermore, as shown in FIG. 10, in this stamper 20, the bottom surface of each recess 35 b between each protrusion 35 a constituting the uneven pattern 35 is substantially flush with the uneven pattern forming surface (surface in the present invention) of the stamper 20. It is formed to become. In the present specification, the bottom surface (that is, the concave / convex pattern forming surface) of each recess 35b will be described below as the reference surface (reference surface X) in the present invention. In this case, the reference surface in the present invention is not limited to the reference surface X at the position (including the bottom surface) that coincides with the bottom surface of the recess 35b, and is between the back surface of the stamper and the uneven pattern forming surface (that is, the thickness of the stamper). Can be formed at any position. Also, as shown in FIG. 11, depending on the manufacturing method, the bottom surface of each recess 35b may not be flush, and in this case, any one of the recesses 35b (in this example) A plane including the bottom surfaces of both concave portions 35b) formed on both sides of the convex portion 35a1 can be used as the reference plane X. Furthermore, as shown in FIG. 10, in this concavo-convex pattern 35, the height from the reference plane X to the protruding end is defined for each convex portion 35a according to the length in the radial direction and the length in the circumferential direction. Is formed.

  Specifically, as shown in FIG. 12, the convex portion 35a1 for forming the data track pattern having a radial length L1 of 100 nm in the entire region from the inner peripheral portion to the outer peripheral portion is high from the reference plane X to the protruding end portion. The height H1 shown in FIGS. 10 and 11 (that is, the protruding length of the protrusion 35a1) is 85 nm from the inner periphery to the entire outer periphery. Further, the convex portion 35a2 for forming a preamble pattern having a circumferential length L2 at the inner circumferential portion of 56 nm and a circumferential length L2 at the outer circumferential portion of 147 nm is a height from the reference plane X to the protruding end portion (FIG. 10). , 11 (that is, the protrusion length of the convex portion 35a2) gradually increases from the inner peripheral portion toward the outer peripheral portion, and is 80 nm in the inner peripheral portion and 88 nm in the outer peripheral portion. . Similarly, the convex portion 35a2 for the sector address pattern (2 bits long) having a circumferential length of 56 nm at the inner circumferential portion and a circumferential length of 147 nm at the outer circumferential portion is a height from the reference plane X to the protruding end portion. The length (that is, the protruding length of the convex portion 35a2) gradually increases from the inner peripheral portion toward the outer peripheral portion, and is 80 nm at the inner peripheral portion and 88 nm at the outer peripheral portion. Further, the convex portion 35a2 for the sector address pattern (8-bit length) having a circumferential length of 226 nm at the inner circumferential portion and a circumferential length of 587 nm at the outer circumferential portion is a height from the reference plane X to the protruding end ( That is, the projecting length of the convex portion 35a2 is gradually increased from the inner peripheral portion toward the outer peripheral portion, and is 90 nm at the inner peripheral portion and 98 nm at the outer peripheral portion. As described above, in the stamper 20, the convex portion 35a2 continuously formed along the radial direction has a circumferential length in the radial direction of the convex portion 35a1 formed in the data track pattern formation region Ats. In a portion longer than the length, the height from the reference surface X to the protruding end is formed to be higher than the height H1 of the convex portion 35a1.

  Further, in the convex portion 35a3 for forming a burst pattern, the length L3 between two concave portions 35b3 adjacent to each other in the circumferential direction (the concave portion 35b corresponding to the unit burst region) is 56 nm in the inner peripheral portion and 147 nm in the outer peripheral portion. The height from the reference plane X between the two concave portions 35b3 to the protruding end (height H3 shown in FIGS. 10 and 11: that is, the protruding length between the concave portions 35b3 in the convex portion 35a3) increases as the outer peripheral portion increases. It is formed to be 92 nm at the peripheral portion and 101 nm at the outer peripheral portion. As described above, in the stamper 20, the convex portion 35a continuously formed along both the radial direction and the circumferential direction so as to surround the plurality of concave portions 35b3, from the reference surface X to the projecting end portion in the entire region. The height is formed to be higher than the height H1 of the convex portion 35a1. Note that the difference between the maximum height and the minimum height among the heights of the respective convex portions 35a is 50 nm at the maximum in order to ensure that the respective convex portions 35a can be pushed when pressed against the resin layer 14 described later. The following is preferable.

  On the other hand, as shown in FIG. 1, the press machine 110 includes hot plates 111 and 112 and a vertical movement mechanism 113. The hot plates 111 and 112 heat the intermediate body 10 and the stamper 20 under the control of the control unit 120. Further, as shown in FIG. 20, the hot plate 111 is configured to be able to hold the intermediate body 10 with the resin layer 14 forming surface facing upward, and the hot plate 112 has the concave / convex pattern 35 forming surface facing downward. The stamper 20 in such a state can be held. The vertical movement mechanism 113 moves (lowers) the hot plate 112 toward the intermediate body 10 held by the hot plate 111, so that the stamper 20 held by the hot plate 112 is transferred to the resin layer 14 of the intermediate body 10. Press (press). Further, the vertical movement mechanism 113 separates the stamper 20 pressed against the resin layer 14 from the resin layer 14 by separating (raising) the hot plate 112 from the hot plate 111. The control unit 120 controls the hot plates 111 and 112 to heat both the intermediate body 10 and the stamper 20 and also controls the vertical movement mechanism 113 to press the stamper 20 against the intermediate body 10 (the stamper pressing in the present invention). Treatment) and peeling of the stamper 20 pressed against the intermediate body 10 from the intermediate body 10 (stamper peeling treatment in the present invention).

  Next, a method for manufacturing the stamper 20 will be described with reference to the drawings.

First, as shown in FIG. 13, a nickel layer 26 having a thickness of about 10 nm is formed by vapor-depositing nickel on a silicon disk-shaped substrate 25 polished so as to have a flat surface. The base material used for manufacturing the stamper 20 is not limited to a silicon base material, and various base materials such as a glass base material and a ceramic base material can be used. Then, as shown in FIG. 14, (for example, Nippon Zeon Co., Ltd.: ZEP520A) resist on the nickel layer 26 formed by the spin coating, the resist having a thickness of about 100nm on the surface of the nickel layer 26 layer 27 Form. The resist for forming the resist layer 27 is not limited to the resist described above, and any resist material can be used. Subsequently, the electron beam lithography apparatus is used to irradiate the resist layer 27 with an electron beam to draw a desired exposure pattern 31 (in this example, a pattern corresponding to each convex portion 35a in the stamper 20). Subsequently, the resist layer 27 in this state is developed to erase the portion of the latent image 27a. Thereby, as shown in FIG. 15, the concave / convex pattern 32 is formed on the nickel layer 26. Next, by etching the nickel layer 26 using the concave / convex pattern 32 (resist layer 27) as a mask, a mask pattern 33 made of the nickel layer 26 is formed on the disk-shaped substrate 25 as shown in FIG. To do.

Next, using the nickel layer 26 (mask pattern 33) on the disk-shaped substrate 25 as a mask, for example, by performing a reactive ion etching process using a mixed gas of CF ₄ and O ₂ as shown in FIG. Then, the disk-shaped substrate 25 is etched to form a plurality of recesses 34a to form the uneven pattern 34. At this time, by appropriately adjusting the mixing ratio (flow rate ratio) of CF ₄ and O ₂ , the pressure in the processing apparatus, the amount of energy to be applied, the processing time, and the like, the portion exposed from the mask pattern 33 is adjusted. It is exposed from the mask pattern 33 rather than the concave portion 34a formed in a portion having a short radial or circumferential length (a portion having a narrow opening width: for example, a portion where each convex portion 35a1 of the stamper 20 is formed later). The concave portion 34a formed in the portion having a long radial or circumferential length (a portion having a wide opening width: for example, a portion where the convex portion 35a3 of the stamper 20 is formed later) is deeply etched. . Specifically, as an example, the flow rate ratio of the etching gas of CF ₄ and O ₂ is defined as 35:15 (flow rate of CF ₄ : 35 sccm, O ₂ : 15 sccm), and the pressure in the processing chamber is defined as 0.3 Pa. The microwave power is set to RF 1 kW, the bias power applied to the disk-shaped substrate 25 is set to RF 50 W, and the etching process is performed for 25 seconds. As a result, as shown in the figure, the concave portion 34a having a wider opening width (longer in the radial direction or circumferential direction) than the concave portion 34a having a narrow opening width (short in the radial direction or circumferential direction). A deep uneven pattern 34 is formed.

  Subsequently, the surface of the uneven pattern 34 (the surface of the nickel layer 26 on the disk-shaped substrate 25) is oxidized by immersing the disk-shaped substrate 25 in this state in, for example, a potassium permanganate solution. As a result, a master master (not shown) is completed. Next, as shown in FIG. 18, after the electrode film 21 for electroforming is formed along the uneven shape of the uneven pattern 34 on the master master, an electroforming process is performed using the electrode film 21 as an electrode. As a result, a nickel layer 22 is formed on the electrode film 21 as shown in FIG. Subsequently, the laminate of the electrode film 21 and the nickel layer 22 (the portion that will later become the stamper 20) is peeled from the laminate of the disk-shaped substrate 25 and the nickel layer 26. At this time, since the surface of the concavo-convex pattern 34 is oxidized, the laminate of the electrode film 21 and the nickel layer 22 can be easily peeled off. Thereby, the concave / convex pattern 34 of the master master is transferred to the electrode film 21 and the nickel layer 22 to form the concave / convex pattern 35 (see FIG. 10). Thereafter, the back surface side of the nickel layer 22 is polished and shaped so as to be flat, and the surface of the electrode film 21 is coated with a fluorine-based material to form an adhesion reducing film 23. As shown in FIG. 10, the stamper 20 in which the concave / convex pattern 35 having a plurality of convex portions 35a having different radial lengths and circumferential lengths and heights from the reference plane X to the projecting end portions is completed. To do.

  Next, a process of forming a concavo-convex pattern on the intermediate body 10 using the stamper 20 described above according to the imprint method according to the present invention will be described with reference to the drawings.

  First, the intermediate body 10 and the stamper 20 are set on the press machine 110. Specifically, the intermediate body 10 is attached to the hot plate 111 with the formation surface of the resin layer 14 facing upward, and the stamper 20 is attached to the hot plate 112 with the formation surface of the uneven pattern 35 facing downward. Subsequently, the control unit 120 controls the hot plates 111 and 112 to heat both the intermediate body 10 and the stamper 20. At this time, the hot plates 111 and 112 are each about 100 ° C. higher than the glass transition point (in this example, about 70 ° C.) of the novolac resin in which both the intermediate 10 and the stamper 20 form the resin layer 14. Heat treatment is performed so that the temperature becomes about 170 ° C. Thereby, the resin layer 14 becomes soft and can be easily deformed. In this case, it is preferable to heat so that it may become high temperature within the range of 70 degreeC or more and 120 degrees C or less with respect to the glass transition point of a resin material, and it is still more preferable to heat so that it may become 100 degreeC or more high temperature. Thereby, as will be described later, the stamper 20 can be easily pressed against the resin layer 14.

  Next, the control unit 120 controls the vertical movement mechanism 113 to lower the hot plate 112 toward the hot plate 111, thereby forming the resin layer 14 in the intermediate body 10 on the hot plate 111 as shown in FIG. 20. The concave / convex pattern 35 of the stamper 20 is pressed (stamper pressing process in the present invention). 21 and 22 referred to later, in order to facilitate understanding of the present invention, the length of each convex portion 35a and the opening width of the concave portion 35b in the concave / convex pattern 35 are different from actual lengths. It is illustrated by the opening width. At this time, the vertical movement mechanism 113 maintains a state in which a load of 34 kN is applied over the entire region of the stamper 20 for 5 minutes according to the control of the control unit 120. Further, the hot plates 111 and 112 are subjected to heat treatment so that the temperature of the intermediate body 10 and the stamper 20 does not decrease while the stamper 20 is pressed against the intermediate body 10 by the vertical movement mechanism 113 according to the control of the control unit 120. Continue to execute. During this heat treatment, it is preferable to maintain the temperature within the range of 170 ° C. ± 1 ° C. (for example, the temperature change is within the range of ± 0.2 ° C.). Thereby, the concavo-convex pattern 35 of the stamper 20 is transferred to the resin layer 14 to form the concavo-convex pattern 36.

  In this case, as described above, the stamper 20 used in the imprint apparatus 100 has a convex length of the data track pattern formation region Ats in the circumferential direction among the convex portions 35a formed in the servo pattern formation region Ass. The convex portion 35a2 that is longer than the radial length of the portion 35a1 (the portion where the circumferential length of each convex portion 35a2 is longer than the radial length of the convex portion 35a1) is higher from the reference plane X to the protruding end. The concave / convex pattern 35 is formed to increase the height. Therefore, when pressing is performed so as to apply a uniform pressing force over the entire area of the stamper 20, the convex portion 35a (in this example, the convex portion 35a2) having a long circumferential direction is also applied to the convex portion 35a1, etc. In the same manner as described above, the resin layer 14 is pushed deeply. Further, as described above, as for the convex portion 35a3 for forming the burst pattern, the height from the reference surface X to the protruding end portion between the two concave portions 35b3 adjacent in the circumferential direction increases from the inner peripheral portion to the outer peripheral portion. It is formed so as to be gradually higher, and is formed so as to be higher than the height H1 of the convex portion 35a1 in the entire region. Therefore, the convex portion 35a3 which is difficult to push into the resin layer 14 due to a large area ratio with respect to the concave portion 35b3 when pressed so as to apply a uniform pressing force over the entire region of the stamper 20 is also described above. It is pushed deeply into the resin layer 14 in the same manner as 35a1, 35a2, etc. As a result, the convex portions 35a having different radial lengths and circumferential lengths are almost uniformly pushed into the resin layer 14.

  Specifically, as shown in FIG. 21, for example, in the data track pattern formation region Ats where a plurality of convex portions 35a1 having a radial length L1 of 100 nm are formed, each convex portion 35a1 is pushed. As a result of the resin layer 14 at the site moving smoothly toward the concave portion 35b1 of the stamper 20, each convex portion 35a1 is pushed sufficiently deeply into the resin layer 14 of the intermediate body 10. Therefore, the thickness T1 of the residue (resin layer 14 between the bottom surface of each recess 36b1 and the surface of the metal layer 13) at the portion into which the protrusion 35a1 is pushed is about 28 nm ± 3 nm. On the other hand, as shown in FIG. 22, the servo pattern forming region Ass (in this example, the preamble pattern forming region Aps and the 2-bit length) in which the convex portion 35a2 having a circumferential length L2 of about 147 nm is formed on the outer peripheral portion. In the sector address pattern formation region where the sector address pattern is formed), the height H2 from the reference surface X to the protruding end on the outer peripheral side of the convex portion 35a2 is 88 nm, which is about 3 nm higher than the height H1 of the convex portion 35a1. Therefore, the wide convex portion 35a2 that is harder to be pushed into the resin layer 14 than the convex portion 35a1 is sufficiently deeply pushed into the resin layer 14. Therefore, the thickness T2 of the residue (resin layer 14 between the bottom surface of each concave portion 36b2 and the surface of the metal layer 13) at the portion into which the convex portion 35a2 is pushed is about 29 nm ± 3 nm.

  Further, in this stamper 20, the servo pattern formation region Ass (8-bit length) in which the convex portion 35a2 for the sector address pattern (8-bit length) having a circumferential length of 226 nm in the inner peripheral portion and 587 nm in the outer peripheral portion is formed. (Sector address pattern forming region where the sector address pattern is formed) is also formed so that the height from the reference plane X to the protruding end portion gradually increases from 90 nm to 98 nm from the inner peripheral portion to the outer peripheral portion. The projecting end portion is projected beyond the portion 35a1. For this reason, this convex portion 35a2 is also pushed into the resin layer 14 only by the same degree as the convex portion 35a1. Further, a servo pattern forming region Ass (burst) in which a burst pattern convex portion 35a3 having a circumferential length of 56 nm in the inner peripheral portion and 147 nm in the outer peripheral portion is formed between the two concave portions 35b arranged in the circumferential direction. Also in the pattern formation region Abs), the height from the reference surface X to the protruding end portion is gradually increased from 92 nm to 101 nm from the inner peripheral portion to the outer peripheral portion, and the protruding end portion is protruded from the convex portion 35a1. ing. For this reason, this convex part 35a3 is also sufficient to the resin layer 14, and is pushed in as much as the convex part 35a1. Accordingly, the thickness of the residue at the portion into which the various convex portions 35a having different lengths in the radial direction and the circumferential direction are pushed is substantially the same in the entire area of each data track pattern formation area Ats and each servo pattern formation area Ass. Subsequently, the control unit 120 controls the hot plates 111 and 112 to continue the heat treatment (maintaining a temperature within the range of 170 ° C. ± 1 ° C.), and as shown in FIG. The stamper 20 is peeled from the intermediate body 10 (resin layer 14) by controlling 113 and raising the hot plate 112 (stamper peeling treatment in the present invention). Thereby, the uneven shape of the uneven pattern 35 in the stamper 20 is transferred to the resin layer 14 of the intermediate body 10, so that the uneven pattern 36 is formed on the metal layer 13. Thus, the imprint process is completed.

  Next, the process of manufacturing the information recording medium 1 according to the information recording medium manufacturing method according to the present invention will be described with reference to the drawings.

  First, the resin material (residue) remaining on the bottom surface of the concave portion of the concave-convex pattern 36 in the resin layer 14 is removed by oxygen plasma treatment. At this time, since the thickness of the residue on the metal layer 13 is almost the same over the entire region in the range of 25 nm to 32 nm, the concave portion becomes an unintended wide opening width when removing the residue (the concave portion The situation where the side wall surface is greatly eroded) is avoided. Next, an etching process using a metal etching gas is performed using the uneven pattern 36 (convex portion) as a mask. At this time, as shown in FIG. 24, the metal layer 13 at the bottom of the concave portion of the concave / convex pattern 36 is removed, and the concave / convex pattern 37 made of a metal material is formed on the magnetic layer 12. Subsequently, an etching process using a gas for magnetic material is performed using the concave / convex pattern 37 (the remaining metal layer 13) as a mask. Thereby, the magnetic layer 12 in the portion exposed from the uneven pattern 37 is removed.

  Next, the metal layer 13 remaining on the magnetic layer 12 is removed by performing an etching process using a metal etching gas. Thereby, as shown in FIG. 3, the uneven pattern 5 (uneven pattern 5t, 5s) in which the groove | channel corresponding to each recessed part in the uneven pattern 36 which transferred the uneven | corrugated shape of the stamper 20 was formed in the magnetic layer 12 is formed. . Next, a surface finishing process is performed. In this surface finishing treatment, first, for example, after filling a groove with silicon dioxide (not shown), the surface is flattened by ion beam etching. Next, a protective film is formed on the flattened surface by, for example, DLC (Diamond Like Carbon), and finally a lubricant is applied. Thereby, the information recording medium 1 is completed. In this case, since the information recording medium 1 is manufactured using the concave / convex pattern 37 formed using the concave / convex pattern 36 having concave portions formed so that the opening width thereof becomes a desired width, the concave / convex pattern Each concave portion 5b of the concave / convex pattern 5 (data recording track, servo pattern, etc.) formed by using 36 and 37 also has a desired width. As a result, the occurrence of recording errors and reproduction errors in the information recording medium 1 is avoided.

  Thus, according to the stamper 20 and the imprint method using the stamper 20, the convex portion 35a having the highest height among the convex portions 35a formed in the data track pattern formation region Ats (in this example, , The convex portion 35a (in this example, convex portions 35a2, 35a3, etc.) having a height at least partially higher than that of the convex portion 35a1) is formed in the servo pattern forming region Ass, thereby forming the concave / convex pattern 35. Protrusions that are difficult to push into the resin layer 14 when the stamper 20 is pressed against the resin layer 14 with a uniform pressing force over the entire area of the stamper 20 (each data track pattern formation area Ats and each servo pattern formation area Ass) during printing. Each convex portion 35a in the servo pattern forming region Ass having a large number of 35a is sufficiently formed on the resin layer 14. It can be pushed deep into. For this reason, each projection 35a in the data track pattern formation region Ats and each projection 35a in the servo pattern formation region Ass can be pushed into the resin layer 14 to the same extent and sufficiently, and as a result, the metal layer 13 The thickness T of the upper residue can be made uniform over the entire area of the intermediate body 10. Accordingly, since the time required for removing the residue can be substantially the same over the entire area, each recess 36b in the uneven pattern 36 transferred to the resin layer 14 in the region corresponding to the data track pattern region. It is possible to avoid a situation in which the side wall surface of the steel sheet is eroded and each recess 36b is formed with an unintended wide opening width. As a result, the concave / convex pattern 36 having a concave portion having a desired opening width can be formed with high accuracy over both the data track pattern region and the servo pattern region. Further, by manufacturing the information recording medium 1 using the concavo-convex pattern 36 formed with high accuracy, it is possible to manufacture the information recording medium 1 in which a recording / reproducing error hardly occurs.

  Further, according to this stamper 20, the main pattern is formed in the servo pattern forming region Ass so that the height in the circumferential direction is longer than the convex portion 35a1 at the portion longer than the radial length L1 in the convex portion 35a1. By forming the third convex portion (in this example, the convex portion 35a2) in the invention, the outer peripheral portion thereof, such as the convex portion 35a2 for forming the preamble pattern or the convex portion 35a2 for forming the sector address pattern, is used. In each of the projections 35a, the length in the circumferential direction is longer than the radial length L1 of the projection 35a1 for forming the data track pattern, and the depth is the same as that of the projection 35a1 for forming the data track pattern. It can be pushed into the resin layer 14 as much as possible. For this reason, the thickness of the residue in the area corresponding to the data track pattern area (data track pattern formation area Ats) and the thickness of the residue in the area corresponding to the servo pattern area (servo pattern formation area Ass) are made substantially uniform. be able to.

  Furthermore, according to this stamper 20, the fourth convex portion in the present invention (in this example, in the burst pattern formation region Abs in the servo pattern formation region Ass so that the height in the entire region is higher than the convex portion 35a1. By forming the convex portion 35a3), the burst pattern forming convex portion 35a3 that has a large area ratio with respect to the concave portion 35b3 and is difficult to be pushed into the resin layer 14 is sufficiently deep in the entire region from the inner peripheral portion to the outer peripheral portion. It can be pushed into the resin layer 14 as much as possible.

  Further, according to the method for manufacturing the information recording medium 1 using the stamper 20, the servo signal can be generated by manufacturing the information recording medium 1 using the uneven pattern 36 transferred to the resin layer 14 by the imprint method. Since it can be reliably acquired, the magnetic head can be accurately tracked with respect to a desired track, and the recording data can be accurately recorded on the data recording track and the recording data can be accurately read from the data recording track. The information recording medium 1 can be manufactured.

  In addition, this invention is not limited to said structure and method. For example, the example in which the convex portion 35a3 in the burst pattern formation region Abs is formed higher than the convex portion 35a1 in the data track pattern formation region Ats in the entire region from the inner peripheral portion to the outer peripheral portion has been described. When the circumferential length between the concave portions 35b3 arranged in the circumferential direction at the circumferential portion (the circumferential length of the convex portion 35a3) is shorter than the stamper 20, the portion is formed lower than the convex portion 35a1. be able to. In this example, the part (the outer peripheral part of the convex part 35a3) formed higher than the height H1 of the convex part 35a1 corresponds to "at least a part" in the present invention. As described above, the fourth convex portion (in this example, the convex portion 35a3) in the burst pattern forming region Abs in the servo pattern forming region Ass so that the height at least in part is higher than the convex portion 35a1. In the convex portion 35a3 for forming the burst pattern, the outer peripheral portion that is difficult to be pushed into the resin layer 14 at the time of imprinting is approximately the same as the convex portion 35a1 for forming the data track pattern and has a sufficient depth. It can be reliably pushed into the resin layer 14. Therefore, the residue thickness in the region corresponding to the data track pattern region (data track pattern formation region Ats) and the residue thickness in the region corresponding to the burst pattern region (burst pattern formation region Abs) are made substantially uniform. be able to.

Further, the stamper 20 having the concave / convex pattern 35 in which the portion corresponding to the unit burst area in the information recording medium 1 is constituted by the concave portion 35b3 has been described. However, as in the stamper 20A shown in FIG. The concave / convex pattern 35 can also be formed by forming a portion corresponding to the region with the convex portion 35a. In this case, like the burst pattern formation region Abs in the stamper 20A, at least one of the length L4 along the circumferential direction and the length L5 along the radial direction is much longer than the radial length of the convex portion 35a1. About the convex part 35a (an example of the 5th convex part in this invention), it is preferable to make the height from the reference plane X to a protrusion part higher than the height H1 of convex part 35a1. Thereby, the convex portions 35a2, which are difficult to be pushed into the resin layer 14 at the time of imprint processing (the convex portions 35a whose length L4, L5 is much longer than the length L1) are also described above. Similarly to 35a3, it can be pushed into the resin layer 14 to the same extent as the convex portion 35a1 and to a sufficient depth.

  Further, the stampers 20 and 20A having the burst pattern in which the parallelogram shaped unit burst areas are arranged in the circumferential direction have been described. However, the present invention is applied to a stamper capable of forming a burst pattern in which substantially elliptical or circular unit burst areas are arranged in the circumferential direction. The invention can be applied. Furthermore, for example, as in the stamper 20B shown in FIG. 26, a burst pattern is formed by an uneven pattern 35 in which a plurality of convex portions 35a (a plurality of concave portions 35b) arranged in a zigzag shape along the circumferential direction are arranged in the radial direction. Can also be adopted. The convex portion 35a in the stamper 20B is an example of a third convex portion in the present invention, and a portion indicated by an arrow B shown in the figure is continuously formed along the radial direction. Therefore, for a portion where the circumferential length (the length L6 shown in the figure) of the convex portion 35a is longer than the radial length L1 of the convex portion 35a1, the height from the reference plane X to the protruding end portion is high. It is preferable to make the height H higher than the height H1 of the convex portion 35a1. Thereby, in the imprint process, the convex portion 35a can be pushed into the resin layer 14 to a sufficient depth. As shown in the figure, the state of “continuously formed along the radial direction” in the present invention is in a direction orthogonal to the circumferential direction (direction of arrow R shown in the figure). This includes not only the state of being continuously formed along but also the state of being continuously formed along the direction intersecting at an acute angle with respect to the radial direction.

  Further, as in the stamper 20C shown in FIG. 27, a configuration in which a plurality of parallelogram-shaped convex portions 35a (a plurality of concave portions 35b) are arranged in a check pattern shape to form a burst pattern may be employed. In this case, like the burst pattern formation region Abs in the stamper 20C, at least one of the length L7 along the circumferential direction and the length L8 along the radial direction is much longer than the radial length of the convex portion 35a1. About the convex part 35a, it is preferable to make the height from the reference plane X to the protruding end part higher than the height H1 of the convex part 35a1. Thereby, the convex portions 35a2, which are difficult to be pushed into the resin layer 14 at the time of imprint processing (the convex portions 35a whose length L7, L8 is much longer than the length L1) are also described above. Similarly to 35a3, it can be pushed into the resin layer 14 to the same extent as the convex portion 35a1 and to a sufficient depth.

  Further, in the manufacturing method of the stamper 20 described above, the electrode film 21 and the nickel layer 22 are covered so as to cover the concave / convex pattern 34 formed by etching the disk-shaped substrate 25 using the nickel layer 26 (mask pattern 33) as a mask. However, the manufacturing method of the stamper according to the present invention is not limited to this. For example, the resist layer 27 is formed on the disk-shaped substrate 25 and the resist layer 27 is formed. The stamper 20 can also be manufactured by forming recesses having different depths to form a concavo-convex pattern (not shown), and forming the electrode film 21 and the nickel layer 22 so as to cover the concavo-convex pattern. . Furthermore, by using the stamper manufactured by transferring the uneven shape of the stamper 20 to a stamper forming material as a master stamper, transferring the uneven shape of the master stamper to another stamper forming material, that is, the above-mentioned stamper The stamper according to the present invention can also be manufactured by transferring 20 uneven shapes only an even number of times.

  Further, in the imprint method (manufacturing method of manufacturing the information recording medium 1) by the imprint apparatus 100, before the stamper 20 is peeled off from before the stamper 20 is pressed against the intermediate body 10, Although the heat treatment for both the intermediate body 10 and the stamper 20 is continuously performed, the present invention is not limited to this. For example, after the stamper 20 is sufficiently pressed against the intermediate body 10, the intermediate body It is also possible to employ a process in which the heat treatment on the stamper 20 and the stamper 20 is finished and then the stamper 20 is peeled off. Furthermore, both the stamper 20 and the intermediate body 10 can be cooled to a temperature below the glass transition point of the resin layer 14 prior to the separation of the stamper 20. Further, the resin layer in the present invention is formed using a resin material whose glass transition point is lower than room temperature (for example, about 25 ° C.), and heat treatment and cooling treatment are performed between the stamper pressing treatment and the stamper peeling treatment. A method of forming a concavo-convex pattern on the resin layer without performing it can also be adopted. Furthermore, a resin layer is formed using an ultraviolet curable resin or an electron beam curable resin as the resin material in the present invention, and the resin layer is cured (or semi-cured) by irradiating ultraviolet rays or an electron beam after the stamper pressing treatment. It is also possible to adopt a method of forming a concavo-convex pattern on the resin layer by performing a stamper peeling process after the removal.

  Further, the use of the uneven pattern formed by the imprint method according to the present invention is not limited to the manufacture of a discrete track type information recording medium, the manufacture of a patterned medium having a pattern other than the track-like pattern, and the magnetic recording It can be used for manufacturing various information recording media other than the media (for example, optical recording media and magneto-optical recording media).

2 is a block diagram showing a configuration of an imprint apparatus 100. FIG. 1 is a plan view of an information recording medium 1. FIG. 1 is a cross-sectional view of an information recording medium 1. FIG. FIG. 3 is a cross-sectional view of the intermediate body 10. 2 is a cross-sectional view of a stamper 20. FIG. 4 is a plan view of a data track pattern formation region Ats and a servo pattern formation region Ass in the stamper 20. FIG. 3 is a plan view of a data track pattern formation region Ats in the stamper 20. FIG. 3 is a plan view of a preamble pattern formation area Aps in a servo pattern formation area Ass in the stamper 20. FIG. 4 is a plan view of a burst pattern formation region Abs in a servo pattern formation region Ass in the stamper 20. FIG. It is sectional drawing along the circumferential direction in the stamper 20 with which the bottom face of each recessed part 35b is flush | level. It is sectional drawing along the circumferential direction in the stamper 20 in which the bottom face of each recessed part 35b is not flush | level. It is a relationship figure which shows the relationship between the length of each convex part 35a, and the height from the reference plane X to a protrusion part. FIG. 5 is a cross-sectional view along the circumferential direction of the disk-shaped substrate 25 in a state where a nickel layer 26 is formed on the surface in the manufacturing process of the stamper 20. FIG. 3 is a cross-sectional view along the circumferential direction of the disk-shaped substrate 25 in a state where an exposure pattern 31 is drawn (a latent image 27a is formed) by irradiating an electron beam onto a resist layer 27 formed on a nickel layer 26; FIG. 15 is a cross-sectional view along the circumferential direction of the disk-shaped substrate 25 in a state where the resist layer 27 in the state shown in FIG. 14 is developed to form a concavo-convex pattern 32 on the nickel layer 26. 15 is a cross-sectional view along the circumferential direction of the disk-shaped substrate 25 in a state where a mask pattern 33 is formed by etching the nickel layer 26 using the resist layer 27 (uneven pattern 32) in the state shown in FIG. 15 as a mask. is there. It is sectional drawing along the circumferential direction of the disk-shaped base material 25 in the state which formed the uneven | corrugated pattern 34 by performing the etching process using the mask pattern 33. FIG. It is sectional drawing along the circumferential direction of the disk-shaped base material 25 in the state which formed the electrode film 21 so that the uneven | corrugated pattern 34 shown in FIG. 17 might be covered. It is sectional drawing along the circumferential direction of the disk-shaped base material 25 in the state which formed the nickel layer 22 so that the electrode film 21 shown in FIG. 18 might be covered. FIG. 4 is a cross-sectional view of a state in which a stamper 20 is pressed against a resin layer 14 of the intermediate body 10. It is sectional drawing of the pressing part vicinity of each convex part 35a1 in the state of FIG. It is sectional drawing of the pressing part vicinity of each convex part 35a2 in the state of FIG. FIG. 21 is a cross-sectional view of a state in which the stamper 20 is peeled from the intermediate body 10 in the state shown in FIG. It is sectional drawing of the state which formed the uneven | corrugated pattern 37 by etching the metal layer 13 using the uneven | corrugated pattern 36 shown in FIG. It is a top view of burst pattern formation area Abs in servo pattern formation area Ass in stamper 20A. It is a top view of the burst pattern formation area Abs in the servo pattern formation area Ass in the stamper 20B. It is a top view of the burst pattern formation area Abs in the servo pattern formation area Ass in the stamper 20C. It is sectional drawing of the state which pressed the convex part 16z with short length L11 in the conventional stamper 10z into the resin layer 20z. It is sectional drawing of the state which pushed the convex part 16z with long length L12 in the conventional stamper 10z into the resin layer 20z.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Information recording medium 5,35-37 Uneven | corrugated pattern 5a, 35a, 35a1-35a3 Convex part 5b, 35b, 35b1-35b3, 36b Concave part 10 Intermediate body 11 Disc-shaped base material 12 Magnetic layer 13 Metal layer 14 Resin layer 20, 20A -20C Stamper 100 Imprint device 110 Press 120 Control unit As Servo pattern area At Data track pattern area Abs Burst pattern formation area Aps Preamble pattern formation area Ass Servo pattern formation area Ats Data track pattern formation area L1 to L8 Length H1 H3 Height T1, T2 Thickness X Reference plane

Claims (5)

The stamper side uneven pattern is formed so that an information recording medium in which the data track pattern and the servo pattern are formed in the uneven pattern can be manufactured,
The stamper-side concavo-convex pattern is formed with a plurality of types of convex portions having different heights from the reference surface defined between the front surface and the back surface to the projecting end portion, and in a region corresponding to the data track pattern. A second convex portion having a height that is at least partially higher than the first convex portion having the highest height among the formed convex portions is formed in a region corresponding to the servo pattern ,
The second convex portion is formed continuously along the direction corresponding to the radial direction of the information recording medium, and the length of the direction corresponding to the circumferential direction of the information recording medium is the first convex portion. In the burst pattern of the servo pattern, a third convex part formed so that the height is higher than the first convex part in a portion longer than the length in the direction corresponding to the radial direction in A stamper provided with a fourth convex portion formed around a concave portion corresponding to the unit burst region and formed such that the height of at least a part thereof is higher than that of the first convex portion . The fourth convex portions claim 1 stamper according to the height at the whole is formed so as to be higher than the first protrusion. The stamper side uneven pattern is formed so that an information recording medium in which the data track pattern and the servo pattern are formed in the uneven pattern can be manufactured,
The stamper-side concavo-convex pattern is formed with a plurality of types of convex portions having different heights from the reference surface defined between the front surface and the back surface to the projecting end portion, and in a region corresponding to the data track pattern. A second convex portion having a height that is at least partially higher than the first convex portion having the highest height among the formed convex portions is formed in a region corresponding to the servo pattern,
The second convex portion is formed continuously along the direction corresponding to the radial direction of the information recording medium, and the length of the direction corresponding to the circumferential direction of the information recording medium is the first convex portion. In the burst pattern of the servo pattern, a third convex part formed so that the height is higher than the first convex part in a portion longer than the length in the direction corresponding to the radial direction in A stamper provided with a fifth convex portion that corresponds to each unit burst region and is formed so that the height is higher than that of the first convex portion. Peeling the stamper pressing process presses the stamper side convex pattern of the stamper according to the surface of the base resin material of claims 1 to coated resin layer formed on one third, the stamper from the resin layer An imprint method in which a stamper stripping process is performed in this order, and the uneven shape of the stamper side uneven pattern is transferred to the resin layer to form an etching process mask . An information recording medium manufacturing method for manufacturing an information recording medium using the concave-convex pattern transferred to the resin layer by the imprint method according to claim 4 as a mask for etching treatment .

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