JP4581963B2 - Stamper, uneven pattern forming method, and information recording medium manufacturing method - Google Patents

Description

  The present invention uses a stamper used at the time of manufacturing an information recording medium or the like, a method for forming an uneven pattern by pressing a stamper on a resin layer formed on the surface of a substrate, and transferring the uneven shape, and an uneven pattern transferred to the resin layer. The present invention relates to an information recording medium manufacturing method for manufacturing an information recording medium.

  As a concavo-convex pattern forming 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. Also, in recent years, as a technique for coping with the increase in capacity of information recording media, there is an electron beam lithography method that draws a nanometer size pattern by irradiating an electron beam instead of light to form a concavo-convex pattern. Has been developed. 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 method for forming a concavo-convex pattern to solve this problem, a stamper with a nanometer-sized concavo-convex pattern is pressed against the resin layer on the base material, and the concavo-convex shape of the stamper is transferred to the resin layer to form a nano-pattern on the base material. US Pat. No. 5,772,905 discloses a nanoimprint lithography method for forming a metric uneven pattern (imprint method for forming a nanometer concavo-convex pattern: hereinafter also referred to as “imprint method”). In this imprint method, first, FIG. As shown in 1A, a stamper (mold) 10x (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 is shown. The element is described by adding “x” to the end of the code). Specifically, a desired pattern is formed on the resin layer formed so as to cover the thin film layer 14x such as silicon oxide formed on the surface of the silicon substrate 12x using an electron beam lithography apparatus. After drawing, the thin film 14x is etched by a reactive ion etching apparatus using the resin layer as a mask, thereby forming a concavo-convex pattern 16x (see FIG. 24) having a plurality of features 16ax within the thickness of the thin film 14x. To do. Thereby, the stamper 10x is manufactured.

Next, for example, polymethyl methacrylate (PMMA: resin material) is spin-coated on the surface of a silicon substrate 18x to form a resin layer (thin film layer) 20x having a thickness of about 55 nm. Then, after heating both the laminated body of the base material 18x and the resin layer 20x, and the stamper 10x so that it may become about 200 degreeC, FIG. As shown to 1B, each convex part 16ax of the stamper 10x is pressed against the resin layer 20x on the base material 18x with a pressure of 13.1 MPa (133.6 kgf / cm ² ). At this time, as shown in FIG. 24, the resin material at the portion into which each convex portion 16ax is pushed moves toward the concave portion 16bx formed around the convex portion 16ax. Next, the laminate in a state where the stamper 10x is pressed is allowed to stand until it reaches room temperature (after cooling), and then the stamper 10x is peeled from the resin layer 20x. As a result, FIG. As shown in FIG. 1C and FIG. 27, the concave / convex pattern 16x of the stamper 10x is transferred to the resin layer 20x, and each concave portion (regions) 24bx is formed at the portion where the convex portion 16ax is pushed. Protrusions 24ax are formed, and nanometer-sized uneven patterns 24x are formed on the base material 18x (resin layer 20x).
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 FIGS. 1A and 1B and FIG. 24, the concavo-convex pattern 24x is formed by pressing the stamper 10x formed so that the depth of each concave portion 16bx in the concavo-convex pattern 16x is uniform over the entire region against the resin layer 20x. In this case, for example, in the stamper 10x for manufacturing the information recording medium 100x shown in FIG. 28, the data track pattern formation region Atsx (see FIG. 24) in which the uneven pattern 16x for forming the data track pattern is formed. The concave / convex pattern 16x is formed so that the area ratio of the concave portion 16bx to the convex portion 16ax is different for each region such as the servo pattern forming region Assx (see FIG. 24) where the concave / convex pattern 16x for forming the servo pattern is formed. Is formed.

  Specifically, for example, a unit burst region of a burst pattern in a servo pattern (a plurality of substantially parallelogram regions or a plurality of substantially elliptical (including circular) regions constituting the burst pattern). In the stamper 10x having the concavo-convex pattern 16x composed of the convex portions 16ax, the area ratio of the concave portion 16bx to the convex portion 16ax in the burst pattern forming region Absx (see FIG. 24) for forming the burst pattern is the data track pattern. It is larger than the area ratio of the concave portion 16bx to the convex portion 16ax in the formation region Atsx. Therefore, as shown in FIG. 24, in the imprint process, for example, each protrusion 16ax in the data track pattern formation region Atsx and each protrusion 16ax in the burst pattern formation region Absx are made to be equal in length to the resin layer 20x. In the data track pattern formation region Atsx, the concave portion 16bx is filled with the resin material moved by the pressing of the convex portion 16ax. On the other hand, in the burst pattern formation region Absx, the amount of the resin material that moves due to the pressing of the convex portion 16ax is small (because the volume of the concave portion 16bx is larger than the amount of the resin material that moves due to the pressing), The recess 16bx is not filled with the resin material, and a gap is generated between the top surface of the resin layer 20x and the bottom surface of the recess 16bx.

  In this case, in the concavo-convex pattern forming region A1x (see FIG. 26) where the concavo-convex pattern 16x for forming the data track pattern, the concavo-convex pattern 16x for forming the servo pattern, and the like are formed, the stamper 10x and the substrate 18x are generated during pressing. For example, the convex portion 16ax of the outer peripheral portion Aox moves toward the inner peripheral side as indicated by the arrow Co, and the convex portion 16ax of the inner peripheral portion Aix is, for example, the outer peripheral side as indicated by the arrow Ci. May move towards. On the other hand, as described above, for example, in the burst pattern formation region Absx, in the state where the convex portion 16ax is pushed into the resin layer 20x, the concave portion 16bx is not filled with the resin material as shown in FIG. In this state, a gap is generated between the upper surface of the recess and the bottom surface of the recess 16bx. In this state, when, for example, the outer peripheral portion Aox of the stamper 10x moves toward the inner periphery in the direction of the arrow Co with respect to the base material 18x due to the above-described deflection, as shown in FIG. The resin material in the concave portion 16bx formed in the outer peripheral portion Aox of Absx moves in the concave portion 16bx and sticks to the wall surface on the inner peripheral side of the convex portion 16ax.

  Therefore, as shown in FIG. 27, in the concave / convex pattern 24x transferred to the resin layer 20x, in the portion corresponding to the outer peripheral portion Aox in the burst pattern formation region Absx (the cross-sectional view on the left side in the same drawing) The concave portion 24bx is a distance traveled by the outer peripheral portion Aox of the stamper 10x in the direction of the arrow Co, rather than the radial length L11x (the length corresponding to the radial direction of the information recording medium: see FIG. 25) of the convex portion 16ax. The length L13x in the radial direction becomes longer. As a result, when the information recording medium 100x is manufactured by etching the base material 18x using the concave / convex pattern 24x as a mask, the burst pattern of the concave / convex pattern 105x formed on the base material 18x is formed as shown in FIG. On the outer peripheral side (left side in the figure), the radial length L15x of the concave portion 105bx is longer than the original length L14x (the length corresponding to the radial length L11x of the convex portion 16ax in the stamper 10x). Things happen.

  On the other hand, as shown in FIG. 25, in the data track pattern formation region Atsx, the concave portion 16bx is filled with the resin material when the convex portion 16ax is pushed into the resin layer 20x during the imprint process. Become. For this reason, even if, for example, the outer peripheral portion Aox of the stamper 10x moves toward the inner periphery in the direction of the arrow Co with respect to the base material 18x due to the bending, the resin material in the concave portion 16bx is complementary to the concave portion 16bx. The state in which a typical shape is maintained is maintained. Therefore, as shown in FIG. 27, in the concave / convex pattern 24x transferred to the resin layer 20x, the diameter of the concave portion 24bx in the portion corresponding to the outer peripheral portion Aox in the data track pattern formation region Atsx (the cross-sectional view on the right side in the same drawing). The length L12x in the direction is the same as the length L11x in the radial direction (see FIG. 25) of the convex portion 16ax for forming the data track pattern in the stamper 10x. As a result, in the information recording medium 100x obtained by etching the base material 18x using the concave / convex pattern 24x as a mask, as shown in FIG. 28, the outer peripheral side of the data track pattern in the concave / convex pattern 105x formed on the base material 18x ( On the right side in the figure, the radial length L14x of the concave portion 105bx is the original length (the length corresponding to the radial length L11x of the convex portion 16ax in the stamper 10x).

  In this case, when tracking servo control is performed on the information recording medium 100x, it is formed at the position of the end portion in the radial direction in the unit burst area of the burst pattern, that is, at the pressing portion of the concavo-convex pattern 16x in the burst pattern formation area Absx in the stamper 10x. Further, the position of the radial end of the concave portion 105bx and the position of the center of the data track pattern in the radial direction of the data recording track, that is, the pressing portion of the concave / convex pattern 16x in the data track pattern formation region Atsx of the stamper 10x are formed. Further, the positional relationship with the center position in the radial direction in the convex portion 105ax (see FIG. 28) is very important. However, in the information recording medium 100x manufactured using the concavo-convex pattern 24x formed by the conventional imprint method as a mask, the radial length of each concave portion 105b in the inner peripheral portion and the outer peripheral portion of the region corresponding to the burst pattern. While L15x is longer than the original length L14x, in the region corresponding to the data track pattern, the radial length L14x of each concave portion 105b is the original length in the entire region from the inner periphery to the outer periphery. The uneven pattern 105x is formed to have a length. For this reason, the relationship between the radial end position in the unit burst region and the radial center position in the data recording track is different from the original positional relationship in the inner and outer peripheral portions of the information recording medium 100x. It becomes. As a result, accurate tracking control may be difficult at the inner and outer peripheral portions.

  In addition, although the example which a pattern shift | offset | difference (expansion of a recessed part) arises in radial direction due to the bending produced in the stamper 10x and the base material 18x at the time of pressing with respect to the resin layer 20x was demonstrated, it arises in the stamper 10x and the base material 18x Depending on the direction of bending, pattern deviation (expansion of recesses) may occur in the circumferential direction. As described above, in the conventional imprint method, when the concave / convex pattern 24x is formed on the base material 18x, the radial length or the circumferential length (opening length) of each concave portion 24bx is desired. There is a problem that it is difficult to form the length.

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

In order to achieve the above object, the stamper according to the present invention has a stamper-side concavo-convex pattern formed so that an information recording medium having a data track pattern and a servo pattern formed in a concavo-convex pattern can be manufactured. Formed so that the area ratio of the concave portion to the convex portion in the data track pattern forming region corresponding to the data track pattern region is larger than the area ratio of the concave portion to the convex portion in the corresponding burst pattern forming region; and The depth of the concave portion in the data track pattern forming region is smaller than the depth of the concave portion in the burst pattern forming region, and the area of the convex portion in the data track pattern forming region R1 is a value obtained by dividing by the area of the recess, and the burst The value obtained by dividing the area of the convex portion in the turn forming region by the area of the concave portion is R2, the depth of the concave portion in the data track pattern forming region is D1, and the depth of the concave portion in the burst pattern forming region is The stamper-side concavo-convex pattern is formed so that the condition of D1 ≧ (1 + R1) / (1 + R2) × D2 is satisfied and the projecting ends of the convex portions are substantially flush with each other. . In the present specification, the “area ratio of the concave portion to the convex portion” means a value obtained by dividing the area of the concave portion by the area of the convex portion. In addition, the “depth of the concave portion” in the present specification means a distance between the protruding end of the convex portion formed around the concave portion and the bottom surface of the concave portion.

In addition, the stamper according to the present invention is formed with a stamper-side concavo-convex pattern so that an information recording medium in which the data track pattern and the servo pattern are formed as a concavo-convex pattern can be manufactured, and the data track pattern formation corresponding to the area of the data track pattern is formed The area ratio of the concave portion to the convex portion in the burst pattern formation region corresponding to the burst pattern region in the servo pattern is larger than the area ratio of the concave portion to the convex portion in the region, and the data track pattern formation The depth of the concave portion in the burst pattern formation region is shallower than the depth of the concave portion in the region, and the area of the convex portion in the data track pattern formation region is the area of the concave portion. The divided value is R1, and the value in the burst pattern formation area A value obtained by dividing the area of the convex portion by the area of the concave portion is R2, the depth of the concave portion in the data track pattern forming region is D1, and the depth of the concave portion in the burst pattern forming region is D2. , D2 ≦ (1 + R2) / (1 + R1) × D1 is satisfied, and the stamper-side concavo-convex pattern is formed so that the protruding end portions of the respective convex portions are substantially flush with each other.

  Further, the uneven pattern forming 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 the resin layer A stamper peeling process for peeling the stamper from the stamper is executed in this order, and the uneven shape of the stamper side uneven pattern is transferred to the resin layer.

  Moreover, 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 concavo-convex pattern forming method.

According to the stamper according to the present invention, than the area ratio of the recesses with respect to the convex portion of the burst pattern forming region, such that the area ratio of the recesses relative to the convex portion of the data track pattern forming region is increased, and a burst pattern formation Ri by the fact that to form a stamper-side convex pattern as the depth of the concave portion of the data track pattern forming region than the depth of the recess in the region becomes shallower, the amount of the resin material is moved by pushing the projections burst pattern For the data track pattern formation area that is smaller than the formation area, the gap formed between the top surface of the resin layer and the bottom surface of the recess is made sufficiently small as in the burst pattern formation area , or the inside of the recess is made of a resin material. It can be satisfied (a situation where a gap is generated is avoided). Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the concave portion corresponding to the guard band portion (or data recording track) are excessively widened.

Further, a value obtained by dividing the area of the projection in the area of the recess of the data track pattern forming region and R1, the value obtained by dividing the area of the projection in the area of the recess of the burst pattern forming region and R2, the data track pattern When the depth of the recess in the formation region is D1 and the depth of the recess in the burst pattern formation region is D2, the stamper side uneven pattern satisfies the condition of D1 ≧ (1 + R1) / (1 + R2) × D2. As a result of forming the recesses, the recesses can be filled with a resin material in both the data track pattern formation region and the burst pattern formation region during the stamper pressing process.

Further, according to the stamper according to the present invention, the area ratio of the concave portion to the convex portion in the burst pattern forming region is larger than the area ratio of the concave portion to the convex portion in the data track pattern forming region , and the data The part corresponding to the unit burst area is configured as a convex by forming the stamper side uneven pattern so that the depth of the recess in the burst pattern formation area is shallower than the depth of the recess in the track pattern formation area . In the burst pattern formation region where the amount of the resin material that moves due to the pressing of the convex portion is smaller than the data track pattern formation region , it occurs between the top surface of the resin layer and the bottom surface of the concave portion in the same manner as the data track pattern formation region. Make the gap sufficiently small, or fill the recess with resin material (avoids gaps) That) can be. Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the recess corresponding to the unit burst region are excessively widened.

Further, a value obtained by dividing the area of the projection in the area of the recess of the data track pattern forming region and R1, the value obtained by dividing the area of the projection in the area of the recess of the burst pattern forming region and R2, the data track pattern When the depth of the recess in the formation region is D1 and the depth of the recess in the burst pattern formation region is D2, the stamper side uneven pattern satisfies the condition of D2 ≦ (1 + R2) / (1 + R1) × D1 As a result of forming the recesses, the recesses can be filled with a resin material in both the data track pattern formation region and the burst pattern formation region during the stamper pressing process.

  According to the uneven pattern forming method of the present invention, the stamper pressing process using any one of the above stampers and the stamper peeling process are performed in this order, and the uneven pattern of the stamper side uneven pattern is formed into the resin layer. In the stamper pressing process, the gap formed between the top surface of the resin layer and the bottom surface of the recess is made sufficiently small in the entire area of the stamper, or the inside of each recess is filled with a resin material. Can be avoided). Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the concave portion are excessively expanded in the entire region of the resin layer, and to form the concave / convex pattern with high accuracy.

  Further, according to the information recording medium manufacturing method of the present invention, by manufacturing the information recording medium using the concave / convex pattern transferred to the resin layer by the above concave / convex pattern forming method, for example, the unit burst area of the burst pattern The positional relationship between the end portion in the radial direction and the center of the data recording track can be a desired positional relationship over the entire area of the information recording medium. Therefore, with this information recording medium, accurate tracking servo control can be performed, and as a result, occurrence of recording / reproducing errors can be avoided.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the accompanying drawings, the best mode of a stamper, a concavo-convex pattern forming method, and an information recording medium manufacturing method according to the present invention will be described below.

  First, a stamper according to the present invention will be described with reference to the drawings.

  A stamper 1 shown in FIG. 1 is an imprinting master configured to be able to manufacture the information recording medium 40 shown in FIG. 21 in accordance with the information recording medium manufacturing method according to the present invention, and is formed in a disk shape as a whole. ing. In this case, the information recording medium 40 is a discrete track type magnetic recording medium in which both the data track pattern and the servo pattern are formed by the concavo-convex pattern 41, and the data track pattern area and the servo pattern area are in the rotation direction (circumferential direction). ) To be arranged alternately.

  On the other hand, as shown in FIGS. 1 and 2, the stamper 1 has a concavo-convex pattern 5 t having a convex portion 5 a for forming a data track pattern and a plurality of concave portions 5 b (see FIG. 2) ), And a concave / convex pattern 5s having a plurality of convex portions 5a and a plurality of concave portions 5b (see FIG. 2) for forming a servo pattern (on the “stamper side” in the present invention). Servo pattern formation regions Ass on which other examples of the “concave / convex patterns” are formed are alternately arranged in a direction corresponding to the rotation direction (circumferential direction) in the information recording medium 40 (direction of arrow R shown in FIG. 1). It is stipulated in. In this case, the concave / convex patterns 5t and 5s (hereinafter also referred to as “concave / convex pattern 5”) of the stamper 1 are formed with the convex portions 5a corresponding to the concave portions 41b of the concave / convex pattern 41 in the information recording medium 40. The concave portions 5 b are formed corresponding to the convex portions 41 a of the concave / convex pattern 41. In FIG. 2, in order to facilitate understanding of the present invention, the lengths and shapes of the convex portions 5 a and the concave portions 5 b are illustrated with different lengths and shapes from actual ones. Further, in this specification, an area sandwiched between two data track pattern formation areas Ats arranged in a direction corresponding to the rotation direction of the information recording medium (on the downstream side with respect to the rotation direction in one data track pattern formation area Ats). A region from the end to the upstream end with respect to the rotation direction in the other one data track pattern formation region Ats) is defined as a servo pattern formation region Ass.

  In this case, as shown in FIG. 3, the convex portions 5a formed in the data track pattern formation region Ats are convex portions for forming a large number of concentric guard band portions that are divided from each other at a predetermined arrangement pitch. Thus, the information recording medium 40 is continuously formed along a direction corresponding to the circumferential direction (rotation direction: the direction of the arrow R), and is formed in a belt shape long in the circumferential direction. This convex portion 5a has a length L1a of each convex portion 5a along the radial direction of the information recording medium 40 from the inner peripheral portion Ai to the outer peripheral portion Ao of the stamper 1 (hereinafter also referred to as “radial length”) L1a. They are formed to be equal to each other. Further, the recess 5b formed in the data track pattern formation region Ats is a recess for forming a large number of concentric data recording tracks that are divided from each other at a predetermined arrangement pitch. The lengths L1b of the concave portions 5b in the radial direction from the inner peripheral portion Ai to the outer peripheral portion Ao are equal to each other and are equal to the length L1a of the convex portion 5a. Therefore, in the uneven pattern 5t in the data track pattern formation region Ats in the stamper 1, each of the region A1i in the inner peripheral portion Ai, the region A1c in the middle peripheral portion Ac, and the region A1o in the outer peripheral portion Ao (as an example, In the parallelogram region in plan view, the circumferential length is the circumferential length of a pair of convex portions and concave portions in the preamble pattern, and the radial length is a length corresponding to one track pitch. The area ratio of the concave portion 5b to the convex portion 5a is equal to each other.

  Further, as shown in FIG. 2, in the servo pattern formation region Ass, a preamble pattern formation region Aps in which a concavo-convex pattern 5s for forming a preamble pattern is formed, and a concavo-convex pattern 5s for forming an address pattern are formed. The address pattern forming region (not shown) and the burst pattern forming region Abs on which the concave / convex pattern 5s for forming the burst pattern is defined. Further, in the burst pattern formation region Abs, four regions Ab1s to Ab4s corresponding to each signal region in the burst pattern of the information recording medium 40 are defined.

  In this case, as shown in FIG. 4, the convex portion 5a formed in the preamble pattern formation region Aps is a convex portion for forming the concave portion 41b in the preamble pattern (uneven pattern 41), and It is continuously formed along the direction corresponding to the radial direction and is formed in a strip shape long in the radial direction. The convex portion 5a has a length along the circumferential direction in the information recording medium 40 (hereinafter also referred to as “circumferential length”) L2ai, L2ac, L2ao (hereinafter also referred to as “length L2a” when not distinguished). Is formed so as to gradually become longer from the inner peripheral portion Ai of the stamper 1 toward the outer peripheral portion Ao. Further, the recess 5b formed in the preamble pattern formation region Aps is a recess for forming the protrusion 41a in the preamble pattern (uneven pattern 41), and has a length along the circumferential direction in the information recording medium 40 (hereinafter referred to as the concave portion 5b). L2bi, L2bc, L2bo (hereinafter also referred to as “length L2b” when not distinguished from each other) are gradually increased from the inner peripheral portion Ai of the stamper 1 toward the outer peripheral portion Ao. Is formed. In this case, the length L2a of the convex portion 5a and the length L2b of the concave portion 5b are defined to be equal to each other at the same radial position as an example. Therefore, in the uneven pattern 5s in the preamble pattern formation region Aps in the stamper 1, each of the region A2i in the inner peripheral portion Ai, the region A2c in the middle peripheral portion Ac, and the region A2o in the outer peripheral portion Ao (as an example, the periphery thereof) In a parallelogram region in plan view, the length in the direction is the circumferential length of a pair of convex portions and concave portions in the preamble pattern, and the length in the radial direction corresponds to a two-track pitch) The area ratio of the recessed part 5b with respect to the convex part 5a is mutually equal.

  Further, as shown in FIG. 5, the convex portion 5a formed in the burst pattern formation region Abs is a convex portion for forming the concave portion 41b (unit burst region) in the burst pattern (uneven pattern 41), L3ai, L3ac, and L3ao (hereinafter also referred to as “length L3a” when not distinguished from each other) along the circumferential direction in the recording medium 40 are referred to as inner circumferential portions of the stamper 1. It is formed so as to gradually become longer from Ai toward the outer peripheral portion Ao. The concave portion 5b formed in the burst pattern formation region Abs is a concave portion for forming the convex portion 41a in the burst pattern (concave / convex pattern 41), and is a circumference between two convex portions 5a adjacent in the circumferential direction. The direction lengths L3bi, L3bc, and L3bo (hereinafter, also referred to as “length L3b” when not distinguished from each other) are formed so as to gradually increase from the inner peripheral portion Ai of the stamper 1 toward the outer peripheral portion Ao. In this case, the length L3a of the convex portion 5a and the length L3b of the concave portion 5b are defined to be equal to each other at the same radial position as an example. Therefore, in the concave / convex pattern 5s in the burst pattern formation region Abs in the stamper 1, each of the region A3i in the inner peripheral portion Ai, the region A3c in the middle peripheral portion Ac, and the region A3o in the outer peripheral portion Ao (for example, the circumferential direction thereof) Is the total length of the circumferential length of the convex portion corresponding to the unit burst area and the circumferential length of the concave portion in the circumferential direction of the convex portion, and the radial length is 2 track pitches. The area ratio of the concave portion 5b to the convex portion 5a is equal to each other in the parallelogram-like region having a length corresponding to.

  In this case, as shown in FIG. 6, the stamper 1 is formed so that the protruding end portions of the convex portions 5 a constituting the concave-convex pattern 5 are substantially flush. 7 to 16 and 18 to 21 to be referred to later, in order to facilitate understanding of the present invention, the length, height (depth) and shape of each convex portion and each concave portion. Is shown in a different length, height (depth) and shape. Further, in this stamper 1, the depth of the concave portion 5b becomes shallower as the area ratio of the concave portion 5b to the convex portion 5a (hereinafter also simply referred to as “area ratio”) becomes smaller. The depths are formed to be equal to each other. Specifically, in the data track pattern formation region Ats, the area ratio is 1 in all of the regions A1i, A1c, and A1o. In the preamble pattern formation region Aps, the area ratio is 1 in all of the regions A2i, A2c, and A2o. Therefore, the depth D1 of the recess 5b in the data track pattern formation region Ats and the depth (not shown) of the recess 5b in the preamble pattern formation region Aps are defined to be equal to each other. On the other hand, in the burst pattern formation region Abs, the area ratio is 3 in all of the regions A3i, A3c, and A3o. Therefore, the depth D2 of the recess 5b in the burst pattern formation region Abs is defined to be shallower than the depth D1 of the recess 5b in the data track pattern formation region Ats and the depth of the recess 5b in the preamble pattern formation region Aps. Has been.

  Next, a method for manufacturing the stamper 1 will be described with reference to the drawings. In order to facilitate understanding of the present invention, only the preamble pattern formation region Aps, the burst pattern formation region Abs, and the data track pattern formation region Ats in the servo pattern formation region Ass will be described, and other pattern formations will be described. A description of the area is omitted.

  First, as shown in FIG. 7, the surface of the substrate 11 is spin-coated with a resist (for example, Zeon 520A, manufactured by Nippon Zeon Co., Ltd.) on the silicon substrate 11 polished to have a flat surface. The resist layer 12 is formed. The base material used for manufacturing the stamper 1 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. Further, the resist for forming the resist layer 12 is not limited to the above resist, and any resist material can be used. Next, the electron beam lithography apparatus is used to irradiate the resist layer 12 with an electron beam to draw a desired exposure pattern (in this example, a pattern corresponding to each concave portion 5b in the burst pattern formation region Abs). Subsequently, the resist layer 12 in this state is developed to eliminate the portion of the latent image 12a. Thereby, as shown in FIG. 8, the concave portion 13 b is formed in the portion of the latent image 12 a, and the concave-convex pattern 13 is formed on the base material 11. Next, the base material 11 exposed from the resist layer 12 on the bottom surface of the recess 13b is etched using the resist layer 12 on which the concavo-convex pattern 13 is formed as a mask, as shown in FIG. An uneven pattern 14 having a plurality of recesses 14b is formed. At this time, the depth D12 of the recess 14b (the distance between the surface of the substrate 11 and the bottom surface of the recess 14b) is equal to the depth D2 of the recess 5b in the burst pattern formation region Abs in the manufacturing target stamper 1. Etching is performed so that

  Next, after removing the resist layer 12 remaining on the base material 11, the resist 11 is spin-coated on the base material 11 on which the formation of the concavo-convex pattern 14 has been completed, as shown in FIG. A resist layer 15 is formed on the surface. Subsequently, the electron beam lithography apparatus is used to irradiate the resist layer 15 with an electron beam to form a desired exposure pattern (in this example, each recess 5b in the data track pattern formation area Ats and each in the preamble pattern formation area Aps). A pattern corresponding to the recess 5b is drawn. Next, by developing the resist layer 15 in this state, the portion of the latent image 15a disappears. As a result, as shown in FIG. 11, the concave portion 16 b is formed in the portion of the latent image 15 a, and the concave-convex pattern 16 is formed on the base material 11. Subsequently, the base material 11 exposed from the resist layer 15 on the bottom surface of the concave portion 16b is etched using the resist layer 15 on which the concave / convex pattern 16 is formed as a mask, thereby forming the base material as shown in FIG. 11 is formed with a concavo-convex pattern 17 having a plurality of concave portions 17b. At this time, the depth D11 of the concave portion 17b (the distance between the surface of the base material 11 and the bottom surface of the concave portion 17b) is the depth D1 of the concave portion 5b in the data track pattern formation region Ats in the manufacturing target stamper 1. Etching is performed so as to be equal to the depth of the recess 5b in the preamble pattern formation region Aps. Thereafter, the resist layer 15 remaining on the base material 11 is removed to complete the master 18 for manufacturing the stamper 1 as shown in FIG.

  Subsequently, after forming a conductive film by depositing nickel on the formation surface of the concave and convex patterns 14 and 17 on the master 18 (not shown), an electroforming process is performed using the conductive film as an electrode. Thus, as shown in FIG. 14, a nickel layer 19 is formed on the concave / convex pattern forming surface (the upper surface in the same drawing) of the substrate 11. Subsequently, the laminated body of the electrode film and the nickel layer 19 is peeled from the base material 11 (master 18). As a result, as shown in FIG. 15, the concave and convex patterns 14 and 17 of the master 18 are transferred to the electrode film and the nickel layer 19 to form the master 20 having the concave and convex patterns 21 and 22. In this case, in the concave / convex patterns 21 and 22 on the master 20, the concave portions 21b and 22b are formed corresponding to the convex portions 14a and 17a (see FIG. 13) on the master 18, and the concave portions 14b and 17b ( Each convex part 21a, 22a is formed corresponding to FIG. Therefore, the height H2 of the convex portion 21a is equal to the depth D12 of the concave portion 14b in the master 18, and the height H1 of the convex portion 22a is equal to the depth D11 of the concave 17b in the master 18.

  Next, by performing an electroforming process on the formation surfaces of the concave and convex patterns 21 and 22 on the master 20, as shown in FIG. 16, the nickel layer 25 is formed on the concave and convex pattern formation surface (the lower surface in the figure) of the master 20. Form. Subsequently, the nickel layer 25 is peeled from the master 20. Thereafter, the stamper 1 is completed as shown in FIG. 6 by polishing the back surface side of the concave / convex pattern forming surface in the nickel layer 25. In this case, in the concavo-convex pattern 5 in the stamper 1, each concave portion 5 b is formed in the burst pattern forming region Abs corresponding to each convex portion 21 a in the master 20, and data corresponding to each convex portion 22 a in the master 20. Recesses 5b are formed in the track pattern formation region Ats and the preamble pattern formation region Aps. Further, in the concave / convex pattern 5, each convex portion 5 a is formed in the burst pattern forming region Abs corresponding to each concave portion 21 b in the master 20, and the data track pattern forming region corresponding to each concave portion 21 b in the master 20. Each protrusion 5a is formed in the Ats and preamble pattern formation region Aps. Therefore, the depth D2 of the recess 5b in the burst pattern formation region Abs is equal to the height H2 of the projection 21a in the master 20, and the depth D1 of the recess 5b in the data track pattern formation region Ats and the preamble pattern formation region Aps. Is equal to the height H1 of the convex portion 22a in the master 20.

  Subsequently, a step of forming a concavo-convex pattern on the intermediate 30 for manufacturing the information recording medium 40 using the stamper 1 according to the concavo-convex pattern forming method according to the present invention will be described with reference to the drawings. .

  First, as shown in FIG. 17, as an example, a resin material is applied on an intermediate 30 in which a magnetic layer 32 is formed on a base 31 formed of alumina, silicon, glass, ceramic, or the like. By doing so, the resin layer 33 is formed on the intermediate 30. At this time, when the concave / convex pattern 5 of the stamper 1 is pressed against the resin layer 33 during a stamper pressing process, which will be described later, the concave portions 5b are filled with the resin material in the entire area of the concave / convex pattern 5 (resin in the entire area of the stamper 1). Thickness that fills each recess 5b with a material) and a thick residue is not generated in a region where the area ratio of the recess 5b to the protrusion 5a is small, such as the data track pattern formation region Ats and the preamble pattern formation region Aps. The application amount of the resin material is adjusted so as to have a thickness. In this case, as a resin material for forming the resin layer 33, the uneven shape of the uneven patterns 34 and 35 (see FIG. 19) formed when the stamper 1 is peeled off as described later is good as an example. It is preferable to use acrylic resin such as polystyrene resin and methacrylic resin (PMMA), polystyrene, phenol resin, epoxy resin, and novolac resin. The intermediate body 30 forming the resin layer 33 actually includes various functional layers such as a soft magnetic layer and an orientation layer between the base material 31 and the magnetic layer 32. In order to facilitate the description, description and illustration thereof will be omitted. In this example, the base material 31 and the magnetic layer 32 constitute a base material in the present invention.

  Next, the intermediate body 30 and the stamper 1 on which the resin layer 33 is formed are set in a press machine (not shown). Specifically, the intermediate 30 is attached to the press with the resin layer 33 forming surface facing upward, and the stamper 1 is attached to the press with the uneven pattern 5 forming surface facing downward. At this time, as will be described later, in order to prevent the resin material from adhering to the stamper 1 at the time of peeling from the resin layer 33, the surface of the concavo-convex pattern 5 on the stamper 1 is subjected to, for example, a coating treatment of a fluorine-based material to provide an adhesion force. Preferably, a mitigating film is formed. The material for forming the adhesion reducing film is not limited to the fluorine-based coating material, and various materials that can reduce the adhesion with the resin layer 33 can be employed. Subsequently, both the intermediate 30 (resin layer 33) and the stamper 1 are heated. At this time, both the resin layer 33 and the stamper 1 are about 170 ° C., which is about 100 ° C. higher than the glass transition point of the novolac resin forming the resin layer 33 (about 70 ° C. in this example). It heat-processes so that it may become. Thereby, the resin layer 33 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 1 can be easily pressed against the resin layer 33.

  Next, as shown in FIG. 18, the pressing machine is operated to press the concave / convex pattern 5 of the stamper 1 against the resin layer 33 in the intermediate body 30 (stamper pressing process in the present invention). In this case, as an example, a state in which a load of 34 kN is applied over the entire region of the stamper 1 is maintained for 5 minutes. Moreover, it is preferable to continue the heat treatment so that the temperature of the resin layer 33 and the stamper 1 does not decrease while the stamper 1 is pressed against the intermediate body 30 (resin layer 33) by a press. Specifically, 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.) during the stamper pressing process. Subsequently, the stamper 1 is peeled from the intermediate 30 (resin layer 33) while continuing the heat treatment (maintaining a temperature within the range of 170 ° C. ± 1 ° C.) (stamper peeling treatment in the present invention). Thus, as shown in FIG. 19, the concave / convex patterns 34 and 35 are formed in the resin layer 33 by transferring the concave / convex shape of the concave / convex pattern 5 in the stamper 1 to the resin layer 33 on the intermediate body 30. In this case, the convex portions 34a and 35a in the concave and convex patterns 34 and 35 are formed corresponding to the concave portions 5b of the concave and convex pattern 5 in the stamper 1, and the concave portions 34b and 35b are formed corresponding to the convex portions 5a. Thus, the imprint process is completed.

  In this case, in the stamper 1 used in this imprint process, as described above, the concave / convex pattern 5 is formed so that the depth of the concave portion 5b becomes shallower in a region where the area ratio of the concave portion 5b to the convex portion 5a is larger. Specifically, in the concavo-convex pattern 5, the area ratio of the concave portion 5b to the convex portion 5a in the burst pattern forming region Abs is larger than the area ratio of the concave portion 5b to the convex portion 5a in the preamble pattern forming region Aps. The depth of the recess 5b in the burst pattern formation region Abs is smaller than the depth of the recess 5b in the preamble pattern formation region Aps. The concave / convex pattern 5 is formed such that the area ratio of the concave portion 5b to the convex portion 5a in the burst pattern forming region Abs is larger than the area ratio of the concave portion 5b to the convex portion 5a in the data track pattern forming region Ats. In addition, the depth of the recess 5b in the burst pattern formation region Abs is smaller than the depth of the recess 5b in the data track pattern formation region Ats.

  Accordingly, as shown in FIG. 18, even in a region where the amount of the resin material that moves due to the pressing of each convex portion 5 a into the resin layer 33 is small (for example, the burst pattern forming region Abs), it moves by pressing each convex portion 5 a. Each recessed part 5b will be in the state filled with the made resin material. For this reason, even if the outer peripheral portion Ao and the inner peripheral portion Ai of the stamper 1 move in the directions of the arrows Co and Ci shown in FIG. 1 due to the bending of the stamper 1 and the base material 31 during the stamper pressing process, the concave portion 5b A situation in which the resin material inside moves inside the concave portion 5b so as to stick to the side surface of the convex portion 5a is avoided. As a result, as shown in FIG. 19, a situation in which each concave portion 34b in the concave / convex pattern 34 (the concave / convex pattern obtained by transferring the concave / convex pattern 5 in the burst pattern formation region Abs) expands in the radial direction is avoided, and the radial direction of each concave portion 34b. Is a length (desired length) substantially equal to the radial length L11s (see FIG. 6) of each convex portion 5a in the burst pattern formation region Abs in the stamper 1. In addition, with respect to each concave portion 35b in the concave / convex pattern 35 (the concave / convex pattern obtained by transferring the concave / convex pattern 5 in the data track pattern formation region Ats), the length L12t in the radial direction has a length L12t in the data track pattern formation region Ats in the stamper 1. The length (desired length) is substantially equal to the radial length L11t (see FIG. 6) of the convex portion 5a.

  In this case, the amount of the resin material that enters the recess 5 b of the stamper 1 during the stamper pressing process (the height of the protrusion 34 a and the protrusion 35 a formed in the recess 5 b) is the protrusion 5 a with respect to the resin layer 33. Is the sum of the depth at which the convex portion 5a is pushed in and the height of the convex portion formed by the resin material that has moved from the indented portion of the convex portion 5a into the concave portion 5b. In this case, the height of the convex portion formed by the resin material that has moved from the indented portion into the concave portion 5b by the indentation of the convex portion 5a is expressed as “indentation depth of the convex portion 5a” × “area of the convex portion 5a” / “ The area of the recess 5b ". Accordingly, by making the “indentation depth of the convex portion 5 a” + “indentation depth of the convex portion 5 a” × “area of the convex portion 5 a” / “area of the concave portion 5 b” and the depth of the concave portion 5 b equal, The inside of 5b can be filled with a resin material.

Specifically, for example, R1 is a value obtained by dividing the area of the convex portion 5a in the data track pattern formation region Ats by the area of the concave portion 5b, and the area of the convex portion 5a in the burst pattern formation region Abs is the area of the concave portion 5b. The value divided by R is R2, the depth of the recess 5b in the data track pattern formation region Ats is D1, the depth of the recess 5b in the burst pattern formation region Abs is D2, and the indentation depth of each protrusion 5a is In order to fill the recess 5b in the data track pattern formation area Ats and the recess 5b in the burst pattern formation area Abs with the resin material when the stamper pressing process is A,
D1 = A + A × R1, D2 = A + A × R2
It is sufficient to satisfy the conditions. Therefore,
D2 = (1 + R2) / (1 + R1) × D1
By defining the depth D2 of the recess 5b in the burst pattern formation region Abs so as to satisfy the above condition, if the recess 5b in the data track pattern formation region Ats is filled with a resin material during the stamper pressing process, the burst pattern The recess 5b in the formation region Abs can be filled with the resin material in the same manner as the recess 5b in the data track pattern formation region Ats.

  In this case, in the stamper 1, since the data track pattern formation area Ats and the servo pattern formation area Ass are defined corresponding to the data track pattern area and the servo pattern area in the information recording medium 40, the data of the data track pattern formation area Ats is defined. The area is very large with respect to the area of the servo pattern formation region Ass. Accordingly, in the data track pattern formation region Ats, for example, the stamper 1 is bent in the depth direction of the concave portion 5b due to the force applied by the press or the like, and each convex portion 5a is sufficiently deep with respect to the resin layer 33. Pushed in. For this reason, even if the depth D1 of each recess 5b is defined deeper than “A + A × R1”, the recess 5b can be filled with a resin material. On the other hand, the area of the servo pattern formation region Ass is extremely narrow with respect to the area of the data track pattern formation region Ats, so that the bending of the recess 5b in the depth direction due to the force applied by a press machine or the like. It is hard to occur. Therefore, when the depth D2 of each recess 5b in the servo pattern formation region Ass (burst pattern formation region Abs) is defined deeper than the above-mentioned “A + A × R2”, the recess 5b can be filled with a resin material. It has become difficult.

Further, since the area of the servo pattern formation region Ass is extremely narrow relative to the area of the data track pattern formation region Ats, the respective protrusions 5a in the data track pattern formation region Ats cannot be sufficiently pushed into the resin layer 33. In the state, it is difficult to sufficiently push the convex portion 5a in the servo pattern formation region Ass into the resin layer 33 as well. For this reason, the stamper pressing process is completed when the concave portions 5b in the data track pattern forming area Ats are filled with the resin material before the sufficient pressing of the convex parts 5a in the servo pattern forming area Ass is completed. In order to avoid the situation in which the stamper pressing process is completed without filling the concave portions 5b in the servo pattern formation region Ass (burst pattern formation region Abs) with the resin material, It is preferable to define the depth D2 of the recess 5b to be somewhat shallower than “A + A × R2”. Therefore,
D2 ≦ (1 + R2) / (1 + R1) × D1
By defining the depth D2 of the recess 5b in the burst pattern formation region Abs so as to satisfy the above condition, each recess 5b in the data track pattern formation region Ats and each recess 5b in the burst pattern formation region Abs are defined. It can be reliably filled with a resin material.

A value obtained by dividing the area of the convex portion 5a in the preamble pattern forming region Aps by the area of the concave portion 5b is R3, and the depth of the concave portion 5b in the preamble pattern forming region Aps is D3, and the preamble pattern forming region Aps and the burst pattern When the indentation depth of each convex portion 5a in the formation region Abs is A,
D3 = A + A × R3, D2 = A + A × R2
It becomes. Therefore,
D2 = (1 + R2) / (1 + R3) × D3
By defining the depth D2 of the recess 5b in the burst pattern formation region Abs so as to satisfy the above condition, if the recess 5b in the preamble pattern formation region Aps is filled with a resin material during the stamper pressing process, burst pattern formation is performed. The recess 5b in the region Abs can be filled with the resin material.

  Next, the process of manufacturing the information recording medium 40 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 surfaces of the concave portions 34b and 35b of the concave and convex patterns 34 and 35 in the resin layer 33 is removed by oxygen plasma treatment. Next, an etching process is performed using the concave / convex patterns 34 and 35 (the convex portions 34a and 35a) as a mask. At this time, as shown in FIG. 20, the magnetic layer 32 at the bottom surface of the concave portions 34 b and 35 b of the concave and convex patterns 34 and 35 is removed, and the concave and convex pattern 41 is formed on the substrate 31. Subsequently, the resin layer 33 remaining on each convex portion 41a in the concave / convex pattern 41 is removed. Thus, as shown in FIG. 21, the data track pattern and servo in which grooves (concave portions 41b) corresponding to the concave portions 34b and 35b in the concave and convex patterns 34 and 35 to which the concave and convex shape of the stamper 1 is transferred are formed in the magnetic layer 32. A pattern is formed.

  In this case, the concave / convex pattern 41 is formed using the resin layer 33 formed by pressing the stamper 1 to form the concave / convex patterns 34 and 35 as a mask. Accordingly, the lengths L13s and L13t in the radial direction of the concave portions 41b in the concave / convex pattern 41 are substantially equal to the lengths L12s and L12t in the radial direction of the concave portions 34b and 35b in the concave / convex patterns 34 and 35 (see FIG. 19). (Desired length). Next, a surface finishing process is performed. In this surface finishing treatment, first, for example, after filling the 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 40 is completed. In this case, the information recording medium 40 uses the concave and convex patterns 34 and 35 having the concave portions 34b and 35b (see FIG. 19) formed so that the opening width (the length in the radial direction) becomes a desired width. Since it is manufactured, each concave portion 41b of the concave / convex pattern 41 (data recording track, servo pattern, etc.) formed using the concave / convex patterns 34, 35 also has a desired width in the entire area from the inner periphery to the outer periphery. Become.

  As described above, according to the stamper 1 and the method for forming the concavo-convex pattern using the stamper 1, the concavo-convex pattern 5 is formed so that the depth of the concave portion 5b becomes shallower as the area ratio of the concave portion 5b to the convex portion 5a increases. As a result, when each convex portion 5a is pushed into the resin layer 33 during the stamper pressing process at the time of forming the concave and convex pattern, the amount of the resin material that moves into the concave portion 5b by the pressing of the convex portion 5a is the area of the concave portion 5b. Even in a small area, the gap generated between the top surface of the resin layer 33 and the bottom surface of the recess 5b is made sufficiently small, or the recess 5b is filled with a resin material (a situation where a gap is generated is avoided). can do. Therefore, even if the inner peripheral portion Ai or the outer peripheral portion Ao of the stamper 1 moves to the middle peripheral portion Ac side due to the bending of the stamper 1 or the base material 31, for example, the amount of movement of the resin material in the concave portion 5b is sufficient. The movement of the resin material in the recess 5b can be avoided. Thus, the concave and convex patterns 34 and 35 formed by transferring the concave and convex pattern 5 can avoid the situation in which the radial length and the circumferential length of the concave portions 34b and 35b are excessively widened to avoid the concave portions 34b and b having a desired opening length. The uneven patterns 34 and 35 having 35b can be formed with high accuracy.

  Further, according to the stamper 1 and the concavo-convex pattern forming method using the stamper 1, the area ratio of the concave portion 5b to the convex portion 5a in the preamble pattern forming region Aps is larger than the convex portion 5a in the burst pattern forming region Abs. The concave / convex pattern 5 is formed so that the area ratio of the concave portions 5b is increased and the depth of the concave portions 5b in the burst pattern forming region Abs is shallower than the depth of the concave portions 5b in the preamble pattern forming region Aps. Thus, the burst pattern forming region Abs in which the portion corresponding to the unit burst region is configured by the convex portion 5a and the amount of the resin material that moves due to the pressing of the convex portion 5a is small is the same as the preamble pattern forming region Aps. The gap generated between the upper surface of the layer 33 and the bottom surface of the recess 5b is sufficiently small. Kusuru, or can fill the recess 5b with a resin material (to avoid a situation where a gap occurs). Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the recess 34b corresponding to the unit burst region are excessively widened.

  Furthermore, according to the stamper 1 and the concavo-convex pattern forming method using the stamper 1, the convex portion 5a in the burst pattern formation region Abs is larger than the area ratio of the concave portion 5b to the convex portion 5a in the data track pattern formation region Ats. The concave / convex pattern 5 is formed so that the area ratio of the concave portion 5b to the concave portion 5b is larger and the depth of the concave portion 5b in the burst pattern formation region Abs is shallower than the depth of the concave portion 5b in the data track pattern formation region Ats. As a result, the portion corresponding to the unit burst region is configured by the convex portion 5a, and the burst pattern forming region Abs in which the amount of the resin material that moves due to the pressing of the convex portion 5a is small is the same as the data track pattern forming region Ats. A gap formed between the top surface of the resin layer 33 and the bottom surface of the recess 5b. Reduce the amount, or, (to avoid a situation where a gap is generated) that satisfies the recess 5b in the resin material can be. Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the recess 34b corresponding to the unit burst region are excessively widened.

  In this case, a value obtained by dividing the area of the convex portion 5a in the data track pattern formation region Ats by the area of the concave portion 5b is R1, and a value obtained by dividing the area of the convex portion 5a in the burst pattern formation region Abs by the area of the concave portion 5b. Is R2, D1 is the depth of the recess 5b in the data track pattern formation region Ats, and D2 is the depth of the recess 5b in the burst pattern formation region Abs, D2 ≦ (1 + R2) / (1 + R1) × By forming the concavo-convex pattern 5 so as to satisfy the condition of D1, the recesses 5b can be filled with the resin material in the stamper pressing process for both the data track pattern formation region Ats and the burst pattern formation region Abs.

  Further, according to the uneven pattern forming method using the stamper 1, a stamper pressing process for pressing the stamper 1 against the resin layer 33 formed on the intermediate body 30, and a stamper peeling process for peeling the stamper 1 from the resin layer 33. Are performed in this order to transfer the concave / convex shape of the concave / convex pattern 5 to the resin layer 33, so that a gap generated between the upper surface of the resin layer 33 and the bottom surface of the concave portion 5 b in the entire area of the stamper 1 during the stamper pressing process. Can be made sufficiently small, or the inside of each recess 5b can be filled with a resin material (a situation in which a gap is generated is avoided). Therefore, the concave and convex patterns 34 and 35 can be formed with high accuracy by avoiding a situation in which the radial length and the circumferential length of the concave portions 34 b and 35 b are excessively expanded in the entire region of the resin layer 33.

  Further, according to the method for manufacturing the information recording medium according to the present invention, by manufacturing the information recording medium 40 using the uneven patterns 34 and 35 transferred to the resin layer 33 by the uneven pattern forming method according to the present invention, for example, The positional relationship between the radial end of the unit burst area in the burst pattern and the center of the data recording track can be set to a desired positional relationship throughout the information recording medium 40. Therefore, in this information recording medium 40, accurate tracking servo control can be performed, and as a result, occurrence of recording / reproducing errors can be avoided.

  In addition, this invention is not limited to said structure and method. For example, the stamper 1 in which the portion corresponding to the unit burst region in the burst pattern is configured by the convex portion 5a has been described. However, the portion corresponding to the unit burst region in the burst pattern is recessed as in the stamper 1A shown in FIGS. The concave / convex pattern 5s can be formed by 5b. In addition, in both figures, about the same component as said stamper 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted. In this stamper 1A, a region having a larger area ratio of the concave portion 5b to the convex portion 5a is formed so that the depth of the concave portion 5b is shallower, and in regions having the same area ratio, the depth of the concave portion 5b is equal to each other. Yes. Specifically, in the data track pattern formation region Ats, the area ratio is 1 in all of the regions A1i, A1c, and A1o in the same manner as the stamper 1 described above. In the preamble pattern formation region Aps, the area ratio is 1 in all of the regions A2i, A2c, and A2o in the same manner as the stamper 1 described above. Therefore, the depth D1 of the recess 5b in the data track pattern formation region Ats and the depth (not shown) of the recess 5b in the preamble pattern formation region Aps are defined to be equal to each other.

  On the other hand, in the burst pattern formation region Abs of the stamper 1A, as shown in FIG. 23, the area ratio is 1/3 in all of the regions A3i, A3c, and A3o. Therefore, the depth of the recess 5b in the burst pattern formation region Abs is defined to be deeper than the depth of the recess 5b in the data track pattern formation region Ats and the depth of the recess 5b in the preamble pattern formation region Aps. . In other words, in this stamper 1A, the depth of the recess 5b in the data track pattern formation region Ats and the depth of the recess 5b in the preamble pattern formation region Aps are shallower than the depth of the recess 5b in the burst pattern formation region Abs. Yes.

In this case, a value obtained by dividing the area of the convex portion 5a in the data track pattern formation region Ats by the area of the concave portion 5b is R1, and a value obtained by dividing the area of the convex portion 5a in the burst pattern formation region Abs by the area of the concave portion 5b. Is R2, the depth of the recess 5b in the data track pattern formation region Ats is D1, the depth of the recess 5b in the burst pattern formation region Abs is D2, and the indentation depth of each protrusion 5a is A. ,
D1 = A + A × R1, D2 = A + A × R2
It becomes. Therefore,
D1 = (1 + R1) / (1 + R2) × D2
By defining the depth D1 of the recess 5b in the data track pattern formation region Ats so as to satisfy the condition, the data track can be obtained if the recess 5b in the burst pattern formation region Abs is filled with a resin material during the stamper pressing process. The recess 5b in the pattern formation region Ats can be filled with the resin material.

In this case, in this stamper 1A, the area of the servo pattern formation region Ass is extremely narrow with respect to the area of the data track pattern formation region Ats in the same manner as the stamper 1 described above. In a state where the portion 5a cannot be sufficiently pushed into the resin layer 33, it is difficult to sufficiently push the convex portion 5a in the servo pattern formation region Ass into the resin layer 33 as well. For this reason, the stamper pressing process is completed when the concave portions 5b in the data track pattern forming area Ats are filled with the resin material before the sufficient pressing of the convex parts 5a in the servo pattern forming area Ass is completed. In order to avoid a situation in which the stamper pressing process is completed without filling the concave portions 5b in the servo pattern formation region Ass (burst pattern formation region Abs) with the resin material, the data track pattern formation region Ats It is preferable to define the depth D1 of each recess 5b to some extent deeper than “A + A × R1”. Therefore,
D1 ≧ (1 + R1) / (1 + R2) × D2
By defining the depth D1 of each recess 5b in the data track pattern formation region Ats so as to satisfy the condition, each recess 5b in the data track pattern formation region Ats and each recess 5b in the burst pattern formation region Abs The inside can be reliably filled with a resin material.

A value obtained by dividing the area of the convex portion 5a in the preamble pattern formation region Aps by the area of the concave portion 5b is R3, the depth of the concave portion 5b in the preamble pattern formation region Aps is D3, and the preamble pattern formation region Aps and burst When the indentation depth of each convex portion 5a in the pattern formation region Abs is A,
D3 = A + A × R3, D2 = A + A × R2
It becomes. Therefore,
D3 = (1 + R3) / (1 + R2) × D2
By defining the depth D3 of the recess 5b in the preamble pattern formation region Aps so as to satisfy the above condition, if the recess 5b in the burst pattern formation region Abs is filled with a resin material during the stamper pressing process, the formation of the preamble pattern The recess 5b in the region Aps can be filled with the resin material.

  Thus, according to this stamper 1A, the area ratio of the concave portion 5b to the convex portion 5a in the preamble pattern formation region Aps is larger than the area ratio of the concave portion 5b to the convex portion 5a in the burst pattern forming region Abs. In addition, since the concave / convex pattern 5 is formed so that the depth of the concave portion 5b in the preamble pattern forming region Aps is shallower than the depth of the concave portion 5b in the burst pattern forming region Abs, the convex portion 5a is moved by pressing. For the preamble pattern formation region Aps in which the amount of the resin material to be performed is smaller than in the burst pattern formation region Abs, a sufficient gap is formed between the upper surface of the resin layer 33 and the bottom surface of the recess 5b in the same manner as the burst pattern formation region Abs. Or the recess 5b is filled with a resin material (a gap is formed). To avoid a situation) can be. Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the concave portion 34b corresponding to the preamble pattern are excessively widened.

  Further, according to the stamper 1A, the area ratio of the recess 5b to the protrusion 5a in the data track pattern formation region Ats is larger than the area ratio of the recess 5b to the protrusion 5a in the burst pattern formation region Abs. In addition, since the concave / convex pattern 5 is formed so that the depth of the concave portion 5b in the data track pattern forming region Ats is smaller than the depth of the concave portion 5b in the burst pattern forming region Abs, the concave portion 5b is moved by pressing the convex portion 5a. For the data track pattern formation region Ats in which the amount of the resin material to be processed is smaller than in the burst pattern formation region Abs, a gap formed between the upper surface of the resin layer 33 and the bottom surface of the recess 5b is formed in the same manner as the burst pattern formation region Abs. Make it small enough or fill the recess 5b with a resin material (a gap is created) To avoid a situation) can be. Therefore, it is possible to avoid a situation in which the radial length and the circumferential length of the concave portion 34b corresponding to the guard band portion (or data recording track) are excessively widened.

  In this case, a value obtained by dividing the area of the convex portion 5a in the data track pattern formation region Ats by the area of the concave portion 5b is R1, and a value obtained by dividing the area of the convex portion 5a in the burst pattern formation region Abs by the area of the concave portion 5b. Is R2, D1 is the depth of the recess 5b in the data track pattern formation region Ats, and D2 is the depth of the recess 5b in the burst pattern formation region Abs, D1 ≧ (1 + R1) / (1 + R2) × By forming the concavo-convex pattern 5 so as to satisfy the condition of D2, the recesses 5b can be filled with the resin material in the stamper pressing process for both the data track pattern formation region Ats and the burst pattern formation region Abs.

  Furthermore, the stamper 1 according to the present invention uses the stamper manufactured by transferring the uneven shape of the stamper 1 to a stamper forming material as a master stamper, and transfers the uneven shape of the master stamper to another stamper forming material. In other words, the stamper formed by transferring the uneven shape of the stamper 1 only an even number of times is included. The master 18 manufactured in the manufacturing process of the stamper 1 is also included in the stamper according to the present invention. Therefore, instead of the stamper 1 described above, the information recording medium 40 can be manufactured using the stamper or the master 18 formed by transferring the uneven shape of the stamper 1 an even number of times as a stamper. Further, the stamper 1 having the burst pattern in which parallelogram-shaped unit burst regions are arranged in the circumferential direction has been described. However, a stamper capable of forming a burst pattern in which substantially elliptical (including circular) unit burst regions are arranged in the circumferential direction has been described. The present invention can be applied.

  Furthermore, in the uneven pattern forming method using the above-described imprint apparatus (manufacturing method for manufacturing the information recording medium 40), the separation process of the stamper 1 is completed before the stamper 1 is pressed against the intermediate body 30 (resin layer 33). In the meantime, the heat treatment for both the resin layer 33 and the stamper 1 is continuously executed. However, the present invention is not limited to this, and for example, the stamper 1 is sufficiently pressed against the resin layer 33 to some extent. Thereafter, the heat treatment for the resin layer 33 and the stamper 1 may be terminated, and then the stamper 1 may be peeled off. In this case, both the stamper 1 and the intermediate 30 can be cooled to a temperature below the glass transition point of the resin layer 33 prior to the separation of the stamper 1. 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 method of manufacturing the information recording medium 40 by pressing the stamper 1 against the resin layer 33 formed on the intermediate 30 (magnetic layer 32) corresponding to the base material in the present invention has been described. The recording medium manufacturing method is not limited to this. For example, one or more mask layers are formed between the intermediate body 30 and the resin layer 33, and the uneven patterns 34 and 35 transferred to the resin layer 33 by pressing the stamper 1 are etched on the lower layer side. A manufacturing method in which the concavo-convex pattern 41 is formed by etching the magnetic layer 32 using the concavo-convex pattern transferred to the mask layer (the mask layer on the intermediate 30 side) sequentially and transferred to the mask layer on the intermediate 30 as a mask. Can be adopted.

Further, for example, in the data track pattern formation region Ats, the depth of the concave portion 5b in the region A1i, A1c, A1o (see FIG. 3) increases as the area ratio of the concave portion 5b to the convex portion 5a increases. The concave / convex pattern 5 is formed so as to be shallower , and the preamble pattern formation region Aps has a larger area ratio of the concave portion 5b to the convex portion 5a in the regions A2i, A2c, A2o (see FIG. 4). The concave / convex pattern 5 is formed so that the depth of the concave portion 5b becomes shallow , and the burst pattern formation region Abs has a large area ratio of the concave portion 5b to the convex portion 5a in the regions A3i, A3c, A3o (see FIG. 5). As described above, the example in which the concave / convex pattern 5 is formed so that the depth of the concave portion 5b in the region is shallow has been described. For "area" of the object for comparing the serial area ratio of it is not limited to a narrow range, such as in the above example. For example, a region in which the same type of pattern (functionally the same type of pattern or the same type of pattern in shape) is formed as one region, and the concave portion with respect to the convex portion 5a for each region in which a different pattern is formed By comparing the area ratio of 5b, the concave / convex pattern can be formed so as to increase the depth of the concave part 5b in the region having a large area ratio.

2 is a plan view of the stamper 1. FIG. 3 is a plan view showing an example of a data track pattern formation area Ats and a servo pattern formation area Ass (preamble pattern formation area Aps and burst pattern formation area Abs) in the stamper 1. FIG. 3 is a plan view of a data track pattern formation region Ats in the stamper 1. FIG. 3 is a plan view of a preamble pattern formation region Aps in the stamper 1. FIG. 3 is a plan view of a burst pattern formation region Abs in the stamper 1. FIG. 2 is a cross-sectional view of the stamper 1. FIG. FIG. 5 is a cross-sectional view of a state in which a resist layer 12 is formed on a base material 11 to form a latent image 12a in the manufacturing process of the stamper 1. It is sectional drawing of the state which developed the resist layer 12 of the state shown in FIG. 7, and formed the uneven | corrugated pattern 13. FIG. It is sectional drawing of the state which etched the base material 11 using the resist layer 12 in which the uneven | corrugated pattern 13 was formed as a mask, and formed the uneven | corrugated pattern 14. FIG. It is sectional drawing of the state which formed the resist layer 15 on the base material 11 in which formation of the uneven | corrugated pattern 14 was completed, and formed the latent image 15a. It is sectional drawing of the state which developed the resist layer 15 of the state shown in FIG. 10, and formed the uneven | corrugated pattern 16. FIG. It is sectional drawing of the state which formed the uneven | corrugated pattern 17 by etching the base material 11 using the resist layer 15 in which the uneven | corrugated pattern 16 was formed as a mask. It is sectional drawing of the base material 11 of the state which removed the resist layer 15. FIG. 3 is a cross-sectional view of a state in which a nickel layer 19 is formed on the surface of the base material 11 where the concave and convex patterns 14 and 17 are formed. FIG. It is sectional drawing of the state which peeled the base material 11 from the nickel layer 19 (master 20) of the state shown in FIG. FIG. 3 is a cross-sectional view of a state in which a nickel layer 25 is formed on the formation surface of the concave and convex patterns 21 and 22 on the master 20. 3 is a cross-sectional view of the intermediate body 30 in a state where a resin layer 33 is formed on a magnetic layer 32. FIG. 3 is a cross-sectional view of a state in which a stamper 1 is pressed against a resin layer 33. FIG. It is sectional drawing of the state which peeled the stamper 1 from the intermediate body 30 (resin layer 33) of the state shown in FIG. 18, and formed the uneven | corrugated pattern 34,35. FIG. 20 is a cross-sectional view of a state in which a concavo-convex pattern 41 is formed by etching the magnetic layer 32 using the concavo-convex patterns 34 and 35 shown in FIG. 19. FIG. 21 is a cross-sectional view of the information recording medium 40 with the resin layer 33 in the state shown in FIG. 20 removed. It is a top view which shows an example of the data track pattern formation area Ats and the servo pattern formation area Ass (preamble pattern formation area Aps and burst pattern formation area Abs) in the stamper 1A. It is a top view of burst pattern formation area Abs in stamper 1A. It is sectional drawing of the state which stamped the stamper 10x in the resin layer 20x with the conventional imprint method. FIG. 25 is a cross-sectional view showing a state in which the stamper 10x in the state shown in FIG. 24 is bent. It is another cross-sectional view of a state in which the stamper 10x is pushed into the resin layer 20x by a conventional imprint method. It is sectional drawing of the state which peeled the stamper 10x from the resin layer 20x in the conventional imprinting method. It is sectional drawing of the information recording medium 100x manufactured using the uneven | corrugated pattern 24x formed by the conventional imprint method as a mask.

Explanation of symbols

1,1A Stamper 5,5s, 5t, 34,35,41 Concave and convex pattern 5a, 34a, 35a, 41a Convex part 5b, 34b, 35b, 41b Concave part 30 Intermediate body 31 Base material 32 Magnetic layer 33 Resin layer 40 Information recording medium A1i, A1c, A1o, A2i, A2c, A2o, A3i, A3c, A3o area Abs burst pattern forming area Aps preamble pattern forming area Ass servo pattern forming area Ats data track pattern forming area D1, D2 depth L1a, L1b, L2ai, L2ac, L2ao, L2bi, L2bc, L2bo, L3ai, L3ac, L3ao, L3bi, L3bc, L3bo, L11s to L13s, L11t to L13t Length

Claims (4)

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 in the data track pattern formation region corresponding to the data track pattern region rather than the area ratio of the concave portion to the convex portion in the burst pattern formation region corresponding to the burst pattern region in the servo pattern. The concave portion is formed so that the area ratio of the concave portion to the convex portion is large, and the depth of the concave portion in the data track pattern forming region is shallower than the depth of the concave portion in the burst pattern forming region. A value obtained by dividing the area of the convex portion in the data track pattern formation region by the area of the concave portion is R1, and a value obtained by dividing the area of the convex portion in the burst pattern formation region by the area of the concave portion Is R2, and the depth of the recess in the data track pattern formation region is D1, The depth of the recesses of the pattern forming region is taken as D2,
D1 ≧ (1 + R1) / (1 + R2) × D2
A stamper that satisfies the above condition and is formed so that the protruding end portions of the respective convex portions are substantially flush with each other. 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 in the burst pattern forming region corresponding to the burst pattern region in the servo pattern, rather than the area ratio of the concave portion to the convex portion in the data track pattern forming region corresponding to the data track pattern region. The concave portion is formed so that the area ratio of the concave portion to the convex portion is large, and the depth of the concave portion in the burst pattern forming region is shallower than the depth of the concave portion in the data track pattern forming region. A value obtained by dividing the area of the convex portion in the data track pattern formation region by the area of the concave portion is R1, and a value obtained by dividing the area of the convex portion in the burst pattern formation region by the area of the concave portion Is R2, and the depth of the recess in the data track pattern formation region is D1, The depth of the recesses of the pattern forming region is taken as D2,
D2 ≦ (1 + R2) / (1 + R1) × D1
A stamper that satisfies the above condition and is formed so that the protruding end portions of the respective convex portions are substantially flush with each other. And the stamper pressing process presses the stamper side convex pattern in claim 1, wherein the stamper to the resin layer formed by a resin material is applied to the surface of the substrate, a stamper peeling process for peeling the stamper from the resin layer Are performed in this order, and the concavo-convex pattern forming method for transferring the concavo-convex shape of the stamper-side concavo-convex pattern to the resin layer. An information recording medium manufacturing method for manufacturing an information recording medium using the uneven pattern transferred to the resin layer by the uneven pattern forming method according to claim 3 .

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