JP2008251141A - Mold structural and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold structural by which tracking control of a recording and reproducing head is made nearly equal on both surfaces of an information recording medium, following properties of the head upon switching of recording and reproducing surfaces is improved, tracking errors and the number of retry times are reduced and seek time can be reduced and to provide a manufacturing method of the mold structure. <P>SOLUTION: In the manufacturing method of a pair of mold structures used for forming recording and reproducing tracks on the both surfaces of the information recording medium, the pair of mold structures are patterned so that trajectories corresponding to the recording and reproducing tracks of the information recording medium on one zero-th surface and the other first surface of the information recording medium will be nearly specularly symmetric. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mold structure for nanoimprint lithography suitably used for forming a track structure of an information recording medium for recording / reproducing information on both sides of a discrete track medium, a patterned medium, an optical recording medium, etc., and the mold structure The present invention relates to a method for manufacturing a body.

In recent years, the surface recording density of magnetic recording media has been remarkably improved by miniaturization of magnetic particles constituting the recording layer, change of materials, refinement of head processing, and the like. Improvement in density is expected.
However, problems such as incorrect information recording on other tracks adjacent to the recording target track due to the processing limit of the head, the spread of the magnetic field, and crosstalk during playback have become obvious, and surface recording using the conventional improved method The increase in density is at the limit. Therefore, as a candidate for a magnetic recording medium capable of further improving the surface recording density, a discrete track medium having a concavo-convex pattern or a structure in which a magnetic layer is divided to reduce magnetic interaction generated between tracks, A patterned medium has been proposed (see Patent Document 1). In the case of the discrete track medium, the recording layer is formed in a track pattern shape in the data area. In the case of the patterned medium, the recording layer is formed in a pattern shape such as a bit. In the case of the discrete track medium and the patterned medium, the recording layer is formed in a servo pattern shape in the servo area.

  A concave / convex pattern in such a magnetic recording medium is pressed against a resin layer on a substrate by pressing a mold (hereinafter also referred to as “stamper”) in which a nanometer-sized concave / convex pattern is formed. Nanoimprint lithography method for forming a nanometer-sized uneven pattern on a substrate by transferring to a layer (imprint method for forming nanometer-sized uneven pattern: hereinafter, also referred to as “imprint method”) It is proposed to form by (refer patent document 2).

  The stamper performs electroforming on a master plate on which information is formed in a concavo-convex pattern, laminates a metal disc composed of an electroformed layer on the master disc, and transfers the concavo-convex pattern onto the metal disc surface. In general, it is manufactured by a peeling process of peeling from the master.

  Also, in recent years, magnetic disks (hard disks) used in hard disk drives that are rapidly spreading are written with format information and address information before being installed in the drive after being delivered to the drive manufacturer by the magnetic disk manufacturer. Is common. This writing can be performed by a magnetic head, but a method of batch transfer with a mold (hereinafter, also referred to as “master disk”) in which format information and address information are written is efficient.

  In this magnetic transfer method for batch transfer, a magnetic disk generating means such as an electromagnet device or a permanent magnet device is disposed on one or both surfaces of a master disk and a disk to be transferred (slave disk) in close contact with each other. By applying a magnetic field, the information (for example, servo signal) that the master disk has is magnetically transferred to the slave disk. In order to perform magnetic transfer with high accuracy, it is extremely important that the master disk and the slave disk are in close contact with each other without gaps.

  By the way, as a master disk used in this magnetic transfer method, for example, as in Patent Document 3, a concave / convex pattern corresponding to an information signal is formed on the surface of a substrate, and the magnetic layer is coated on the surface of the concave / convex pattern. Is usually used. This master disk for magnetic transfer is electroformed by performing electroforming on a master disk on which information is formed in a concavo-convex pattern, and laminating a metal disk comprising an electroformed layer on the master disk, and transferring the concavo-convex pattern onto the surface of the metal disk. In general, it is manufactured by coating a magnetic layer on the surface of the concavo-convex pattern after passing through a process, a peeling process for peeling the metal disk from the master, and a punching process for punching the peeled metal disk to a predetermined size. .

  When transferring a concavo-convex pattern on both sides of an information recording medium for recording / reproducing information on both sides of such a discrete track medium, patterned medium, optical recording medium, etc., as shown in FIG. The rotation-synchronized shake (RRO) resulting from the axial runout at the center of rotation is reproduced, and the locus of the track of interest in the drawing area deviates from a perfect circle. Therefore, a technique is disclosed in which the stamper pattern is brought close to a perfect circle and the center point thereof coincides with the rotation center of the disk. However, a technique for matching the projection pattern on the disk plane of a substantially concentric locus corresponding to the recording / reproducing track of the information recording medium for recording / reproducing on both sides as much as possible on both sides, including the amplitude and phase component of the deviation (RRO) from the concentric circle. There is no disclosure about.

For example, in Patent Document 4, since an exposure apparatus having a rotary stage has a shake of a rotary table, a method of drawing a measurement circle in advance and measuring a rotationally synchronized shake to compensate for the shake and increasing the roundness Has been proposed. However, in this proposal, the pattern fluctuation cannot be made zero, and a correction process is required.
Further, in Patent Document 5, when a patterned medium is manufactured using a nanoimprint technique, a relative alignment technique between a mold and a disk is important, and an alignment mark and a central hole or an outer circumferential edge of the disk are used. An alignment method has been proposed. However, this proposal only discloses that the center of the disk and the single-sided transfer mold are aligned.
Further, Patent Document 6 proposes a method of magnetic transfer after aligning servo patterns on both sides simultaneously. However, in this proposal, both stampers and the center of the disk are aligned at the same time, but there is no disclosure or suggestion about matching the pattern runout.

In general, in recording and reproducing while tracking such as a hard disk (HDD), eccentricity is allowed to some extent and can be corrected by a drive (see Patent Document 7 and Non-Patent Document 1). On the other hand, a plurality of hard disk (HDD) heads are fixed to one rotating mechanism, and are simultaneously controlled and driven by one HSA (head stack assembly) (see Non-Patent Document 2). As described above, the recording / reproducing operation in the HDD is not performed by a plurality of heads at the same time. However, from the viewpoint of performing the tracking operation at the time of switching the head smoothly and accurately with a high track density disk, In addition to matching the center of rotation of the disk, it is preferable that the eccentricity and runout components of the tracks on each side of the disk are also aligned.
In the case of a hard disk, the front and back of one medium are written with the same head, so the eccentricity is relatively small. However, with patterned media, the front and back surfaces are patterned with different stampers. Even if they are combined, there is a problem that deviation from the concentric circles and eccentricity are not aligned.

JP 2000-195042 A JP-A-2005-353164 JP 2001-256644 A JP 2006-30055 A JP 2006-40321 A JP 2006-134485 A JP 2003-281841 A "Servo track writing technology" FUJITSU. 58, 1, p. 29-34 (01, 2007) “Structure and application of hard disk drive” p. 39-44, issued by CQ Publisher

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, according to the present invention, the tracking control of the recording / reproducing head is substantially the same on both sides of the information recording medium, the followability of the head when switching the recording / reproducing surface is improved, the tracking error and the number of retries are reduced, and the seek time is reduced. An object of the present invention is to provide a mold structure capable of reducing the above and a method for manufacturing the mold structure.

Means for solving the problems are as follows. That is,
<1> A method for producing a pair of mold structures used for forming recording / reproducing tracks on both surfaces of an information recording medium,
The pair of mold structures are patterned so that the trajectory corresponding to the recording / reproducing track of the information recording medium is substantially mirror-symmetrical between the first 0th surface and the other first surface of the information recording medium. This is a method for manufacturing a mold structure.
<2> A reversal pattern is formed by electroforming from the pattern of the master for the 0th surface to produce a mold structure for forming the 0th surface,
An electroformed master having a reversal pattern formed by electroforming from the pattern of the first surface master is formed, and a reversal pattern is further formed by electroforming from the pattern of the electroformed master. It is a manufacturing method of a mold structure given in the above <1> to produce.
<3> The method for producing a mold structure according to <2>, wherein the pattern of the master for the 0th surface and the pattern of the master for the first surface are substantially the same.
<4> The mold structure according to any one of <2> to <3>, wherein a positive resist material is used for pattern formation of the 0th surface master and a negative resist material is used for pattern formation of the first surface master. It is a manufacturing method of a body.
<5> The method for producing a mold structure according to any one of <1> to <4>, wherein the information recording medium is any one of a discrete track medium, a patterned medium, an optical recording medium, and a magnetic transfer medium. is there.
<6> A mold structure manufactured by the method for manufacturing a mold structure according to any one of <1> to <5>.

  According to the present invention, the conventional problems can be solved, and the tracking control of the recording / reproducing head is almost the same on both sides of the information recording medium, the followability of the head when switching the recording / reproducing surface is improved, and the tracking error In addition, it is possible to provide a mold structure that can reduce the number of retries and reduce seek time, and a method of manufacturing the mold structure.

(Mold structure and method for producing mold structure)
The method for producing a mold structure of the present invention is a method for producing a pair of mold structures used for forming recording / reproducing tracks on both surfaces of an information recording medium,
The pair of mold structures are patterned so that the trajectory corresponding to the recording / reproducing track of the information recording medium is substantially mirror-symmetrical between the first 0th surface and the other first surface of the information recording medium. .
Here, “the locus corresponding to the recording / reproducing track is substantially mirror-symmetrical between the first 0th surface and the other first surface of the information recording medium” means that the pair of mold structures are It means that the tracks (for example, convex portions, concave portions, etc.) corresponding to the recording / reproducing tracks are almost completely overlapped when they are overlapped via the information recording medium. However, the case where there is a recording / playback track unique to one surface for the purpose of identifying the surface and the like and there is no track corresponding to the other surface is also included.
The 0th surface and the first surface correspond to the front surface and the back surface of the information recording medium.
The information recording medium is preferably any one of a discrete track medium, a patterned medium, an optical recording medium, and a magnetic transfer medium.
The mold structure of the present invention is manufactured by the method for manufacturing a mold structure of the present invention.
Hereinafter, the details of the mold structure of the present invention will be clarified through the description of the method for producing the mold structure of the present invention.

In the method for producing a mold structure of the present invention, a reversal pattern is formed by electroforming from the pattern of the master for the 0th surface to produce a mold structure for forming the 0th surface,
An electroformed master having a reversal pattern formed by electroforming from the pattern of the first surface master is formed, and a reversal pattern is further formed by electroforming from the pattern of the electroformed master. It is preferable to prepare them and use them as the pair of mold structures.
Hereinafter, the manufacturing method of the 0th surface and the 1st surface formation mold structure is demonstrated with reference to drawings.

<Preparation of 0th surface forming mold structure>
Here, FIG. 2A to FIG. 2E are process diagrams showing a manufacturing method of the 0th surface forming mold structure.
First, as shown in FIG. 2A, a pretreatment such as adhesion layer formation is performed on a substrate 15 having a smooth and clean surface, and an electron beam resist solution is applied by a spin coat method or the like to form a resist film 16, Bake.
Examples of the substrate include nickel, silicon, quartz plate, glass, aluminum, ceramics, and synthetic resin.
As the material of the resist film, either a positive resist material or a negative resist material may be used, but a different one from the first surface forming mold structure is used for pattern formation of the 0th surface master. When a positive resist material is used, it is preferable to use a negative resist material for pattern formation of the first surface master.
In FIG. 2A, a positive resist material is used.

There is no restriction | limiting in particular as said positive type resist material, According to the objective, it can select suitably, For example, FEP-171 (made by Fuji Film Electronics Materials Co., Ltd.) etc. are mentioned.
There is no restriction | limiting in particular as said negative resist material, According to the objective, it can select suitably, For example, FEP-270 (made by FUJIFILM Electronics Materials Co., Ltd.) etc. are mentioned.

Next, as shown in FIG. 2B, a substrate 15 mounted on the stage is modulated in accordance with a servo signal or the like by an electron beam exposure apparatus (not shown) equipped with a high-precision rotary stage or XY stage. The desired concavo-convex pattern P ′ is drawn and exposed on the resist film 16 by irradiation with the electron beam.
Here, the drawing on the master for the 0th surface and the master for the first surface is a substantially congruent figure including rotationally synchronized runout (RRO) caused by axial runout at the rotation center of the drawing apparatus. Thus, the XY stage and the beam are moved by the same method and the same procedure. For example, the conditions affecting the RRO component such as the moving direction of the XY stage, the sequence, and the beam swinging direction are all the same. However, the patterns required for identifying the 0th surface and the first surface, or for positioning, etc. may be different.
In addition, the exposure conditions necessary to make the patterns of the positive resist material and the negative resist material into the required shapes can be set separately.

  Next, as shown in FIG. 2C, the resist film 16 is developed, and a desired concavo-convex pattern P ′ is formed by the resist film 16 remaining after removing the exposed portion. A conductive layer (not shown) is provided on the concavo-convex pattern P ′ by, for example, stapling to produce a 0-th surface master 17 that can be electroformed.

Next, as shown in FIG. 2C, the entire surface of the zeroth surface master 17 is subjected to electroforming with an electroforming apparatus (not shown), and a desired thickness (Ni electroformed layer) of Ni metal is laminated.
Usually, the metal used for the mold is nickel (Ni). However, when the mold is manufactured by electroforming, it is preferable to use a nickel sulfamate bath in which a mold with low stress can be easily obtained. Such a nickel sulfamate bath is composed of, for example, a surfactant (for example, sodium lauryl sulfate) based on 400 g / L to 800 g / L of nickel sulfamate and 20 g / L to 50 g / L (supersaturated) of boric acid. Additives are added as necessary. The bath temperature of the plating bath is preferably 40 ° C to 60 ° C. It is preferable to use a nickel ball in a titanium case for the counter electrode during electroforming.

  Next, the metal disk 18 is peeled off from the 0th surface master 17, and the remaining resist film 16 is removed and washed. As a result, as shown in FIG. 2D, a mold master 11 ′ having an inverted concavo-convex pattern P and having an outer diameter D before being punched into a predetermined size is obtained. The master 11 'is punched out, and the back surface is polished as necessary, so that a 0th surface forming mold structure 10 having a predetermined size of the outer diameter d shown in FIG. 2E is obtained.

<Preparation of mold structure for first surface formation>
In the production of the first surface forming mold structure, a first surface master was produced in the same manner except that a resist material different from the production of the 0th surface master in the 0th surface forming mold structure was used. did.
Next, a first surface electroformed master in which a reversal pattern was formed by electroforming from the pattern of the first surface master was produced in the same manner as the above-described 0th surface forming mold structure.
Next, a reversal pattern was further formed from the pattern of the electrocasting master for the first surface by electroforming in the same manner as the above-described mold structure for forming the zeroth surface, to produce a mold structure for forming the first surface.

  The obtained 0th surface forming mold structure and 1st surface forming mold structure are such that the locus corresponding to the recording / reproducing track of the information recording medium has one 0th surface of the information recording medium and the other. Since the first surface of the recording medium is substantially mirror-symmetrical, the tracks (projections, recesses, etc.) corresponding to the recording / reproducing tracks almost completely overlap when they are overlapped via the information recording medium. As a result, the projection pattern on the disk plane of the substantially concentric locus corresponding to the recording / reproducing track of the information recording medium to be recorded / reproduced on both sides should be matched on both sides including the amplitude and phase component of the deviation (RRO) from the concentric circles. Can do.

  Examples of the other steps include a protective layer forming step. When a magnetic transfer master disk is manufactured as the mold, a magnetic layer forming step of forming a magnetic layer on the surface of the manufactured mold is included. The magnetic transfer master disk may be subjected to end face processing and back surface polishing.

  In the above embodiment, the positive resist material is used for the 0th surface, and the beam drawing region corresponds to the convex portion of the mold structure. However, the combination of the surface, the resist type, and the drawing data is as follows. Any combination may be used as long as a mold structure having a desired concavo-convex shape is obtained, and a combination with a small drawing area and a short drawing time is preferable from the viewpoint of productivity and drawing accuracy.

<Configuration of mold structure>
FIG. 3 is a partial perspective view showing a configuration in an embodiment of a mold structure according to the present invention.
As shown in FIG. 3, in the mold structure 1 of the present embodiment, a plurality of convex portions 3a are concentrically formed on one surface 2a (hereinafter sometimes referred to as a reference surface 2a) of a disc-shaped substrate 2. , Formed at predetermined intervals.
In the present embodiment, the convex portion 3 a and the concave portion 3 b formed between the plurality of convex portions 3 a are collectively referred to as the concave and convex portion 3.
As the substrate 2, nickel, silicon, quartz plate, glass, aluminum, ceramics, synthetic resin, or the like is used.
Moreover, the cross-sectional shape of the convex part 3a in the radial direction of the concentric circle (direction in which the convex parts 3a are arranged) is, for example, a rectangle.
In addition, the cross-sectional shape of the said convex part 3a is not restricted to a rectangle, According to the objective, arbitrary shapes can be selected by controlling the etching process mentioned later.
Hereinafter, in the description of the present embodiment, “cross section (shape)” refers to a cross section (shape) in the radial direction of the concentric circles (direction in which the convex portions 3 a are arranged) unless otherwise specified.
Moreover, it is preferable that the thickness of the board | substrate 2 is 0.01 mm or more and less than 0.5 mm.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Comparative Example 1)
-Production of mold structure for 0th surface formation-
As shown in FIG. 2A, a positive resist solution (FEP-171, manufactured by FUJIFILM Electronics Materials Co., Ltd.) is applied onto a substrate 15 made of a silicon wafer having a smooth surface and a smooth surface by spin coating. Was formed and baked. Then, with an electron beam exposure apparatus (not shown) equipped with a high-precision rotary stage or XY stage, the original plate 15 mounted on the stage is irradiated with an electron beam B modulated in accordance with a servo signal or the like, A desired concavo-convex pattern P ′ was drawn and exposed on the resist film 16.
The drawing on the master for the 0th surface and the master for the first surface is substantially congruent, including rotationally synchronized runout (RRO) caused by axial runout at the rotation center of the drawing apparatus. -The Y stage and the beam were moved by the same method and the same procedure. For example, the conditions affecting the RRO component, such as the stage moving direction, sequence, and beam swaying direction, are all the same.

  Next, as shown in FIG. 2B, the resist film 16 was developed, and a desired concavo-convex pattern P ′ was formed by the resist film 16 remaining after removing the exposed portion. A conductive layer (not shown) was applied on the concave / convex pattern P ′ by stamping to produce an electroforming zero-side master 17. As shown in the left drawing of FIG. 4A, the track of interest is formed as a recess 103 in the zeroth surface master 17.

Next, as shown in FIG. 2C, the electroforming process is performed while immersing the 0th surface master 17 provided with the conductive layer in a Ni electroforming bath having the following composition and rotating at a rotation speed of 50 to 150 rpm. went. As a result, a metal disc having a total thickness of 300 μm was formed.
-Ni electroforming bath composition and temperature-
・ Nickel sulfamate ... 600g / L
・ Boric acid ... 40g / L
・ Surfactant (sodium lauryl sulfate) ... 0.15 g / L
・ PH = 4.0
・ Temperature = 55 ℃

Next, the metal disk was peeled from the 0th surface master 17, and the remaining resist film 16 was removed and washed. As a result, as shown in FIG. 2D, a 0th-surface master 11 ′ having an inverted concavo-convex pattern P and having an outer diameter D before being punched into a predetermined size was obtained. The 0th surface master 11 ′ is punched out, the back surface is polished to a surface roughness (Ra) of 1 μm or less, and the 0th surface of 2.5 inch size (disk outer diameter 65 mm, inner diameter 24 mm) shown in FIG. 2E is formed. A mold structure 10 for manufacturing was produced.
In the first surface forming mold structure 10, the track of interest is formed as a convex portion 104 as shown in the right side of FIG. 4A.

-Production of mold structure for first surface formation-
A master for the first surface was produced in the same manner as the production of the 0th surface forming mold structure. As shown in the left diagram of FIG. 4B, the track of interest is formed as a recess 203 in the first surface master 201.
Next, using the first surface master 201, a first surface forming mold structure was manufactured in the same manner as the 0th surface forming mold structure. In this first surface forming mold structure 202, a track of interest is formed as a convex portion 204 as shown in the right side of FIG. 4B.

  Next, when the 0th surface forming mold structure 10 of the comparative example 1 and the first surface forming mold structure 202 of the first comparative example are used and overlapped via the information recording medium 105 as shown in FIG. The convex portion 104 (represented by a dotted line) and the convex portion 204 (solid line) of the track of interest are not substantially mirror-symmetrical, resulting in a shift.

Example 1
-Production of mold structure for 0th surface formation-
Similarly to Comparative Example 1, the 0th surface master 101 in which the track of interest is formed as the groove 103 shown in the left diagram of FIG. 6A is produced, and the 0th surface master 101 is used and shown in the right diagram of FIG. 6A. A 0th surface forming mold structure 102 was produced. In the 0th surface forming mold structure 102, the track of interest is formed as a convex portion 104 as shown in the right side of FIG. 6B.

-Production of mold structure for first surface formation-
A negative resist solution (FEP-270, manufactured by FUJIFILM Electronics Materials Co., Ltd.) was applied on a substrate 15 made of a silicon wafer having a smooth and clean surface by spin coating to form a resist film 16 and baked. Then, with an electron beam exposure apparatus (not shown) equipped with a high-precision rotary stage or XY stage, the original plate 15 mounted on the stage is irradiated with an electron beam B modulated in accordance with a servo signal or the like, A desired concavo-convex pattern P ′ was drawn and exposed on the resist film 16.
The drawing on the master for the 0th surface and the master for the first surface is substantially congruent, including rotationally synchronized runout (RRO) caused by axial runout at the rotation center of the drawing apparatus. -The Y stage and the beam were moved by the same method and the same procedure. For example, the conditions affecting the RRO component, such as the stage moving direction, sequence, and beam swaying direction, are all the same.

Next, a first surface master 301 capable of electroforming was manufactured in the same manner as the manufacture of the 0th surface forming mold structure of Comparative Example 1.
As shown in FIG. 6B, the target track 301 is formed with convex portions 304 on the first surface master 301.

Next, using the first surface master 301, a first surface electroformed master 302 was manufactured in the same manner as the manufacture of the 0th surface forming mold structure of Comparative Example 1. As shown in FIG. 6B, the target track is formed as a recess 305 in the first surface electroformed master 302.
Next, the first surface forming mold structure 303 was produced by electroforming in the same manner as the production of the 0th surface forming mold structure of Comparative Example 1 using the first surface electroforming master 302. .
In this first surface forming mold structure 303, as shown in FIG. 6B, the track of interest is formed as a convex portion 306.

  Next, when the 0th surface forming mold structure 102 of Example 1 and the first surface forming mold structure 303 of Example 1 are used and overlapped via the information recording medium 105 as shown in FIG. In both cases, the convex portion 104 and the convex portion 306 of the track of interest are substantially mirror-symmetric and overlapped without deviation.

<Performance evaluation>
The magnetic signals of each of the disks produced in Example 1 and Comparative Example 1 were measured by fixing or tracking the head with a high-precision spin stand, and the RROs on both sides were read / write testers for hard disks (BitFinder, manufactured by Aimes Corporation). In the first embodiment, the projection pattern on the disk plane of the substantially concentric locus corresponding to the recording / reproducing track of the information recording medium for recording / reproducing on both sides is the amplitude and phase component of deviation (RRO) from the concentric circle. It was found that they were consistent with each other.
On the other hand, in Comparative Example 1, a deviation occurred in the amplitude and phase component of RRO.

  In the disk of Example 1, the tracking control of the recording / reproducing head is almost the same on both sides of the information recording medium, the head followability at the time of switching the recording / reproducing surface is improved, the tracking error and the number of retries are reduced, and the seek is performed. It can be estimated that the time can be reduced.

  The mold structure manufactured by the method for manufacturing a mold structure of the present invention shifts the projection pattern on the disk plane of a substantially concentric circle corresponding to the recording / reproducing track of the information recording medium to be recorded / reproduced on both sides from the concentric circle ( RRO) can be matched on both sides including the amplitude and phase components, for example, a magnetic recording medium having a concave-convex pattern recording layer such as discrete track media, patterned media, and a palm type having a continuous recording layer of the concave-convex pattern It can be applied to the manufacture of magnetic recording media, magneto-optical recording media, optical recording media, hard disks, and various semiconductor products.

FIG. 1 is a schematic diagram showing the deviation of the locus of the track of interest from the perfect circle in the drawing area of the information recording medium. FIG. 2A is a diagram illustrating a process of forming a resist film on a substrate and performing baking in the method for manufacturing a mold structure of the present invention. FIG. 2B is a diagram showing an exposure step in the method for manufacturing a mold structure of the present invention. FIG. 2C is a diagram showing a concavo-convex pattern forming step in the method for producing a mold structure of the present invention. FIG. 2D is a diagram showing a step of peeling the metal disk from the master disk in the method for manufacturing a mold structure of the present invention. FIG. 2E is a diagram showing a step of punching a metal disc and producing a mold of a predetermined size in the method for manufacturing a mold structure of the present invention. FIG. 3 is a partial perspective view showing a configuration in an embodiment of a mold structure according to the present invention. FIG. 4A is a diagram showing a pattern on the 0-th surface side in the conventional mold structure manufacturing method. FIG. 4B is a diagram showing a pattern on the first surface side in the conventional mold structure manufacturing method. FIG. 5 is a diagram showing a pattern transfer method using the 0th surface forming mold structure of FIG. 4A and the first surface forming mold structure of FIG. 4B. FIG. 6A is a diagram showing a pattern on the 0th surface side in the method for manufacturing a mold structure of the present invention. FIG. 6B is a diagram showing a pattern on the first surface side in the method for manufacturing a mold structure of the present invention. FIG. 7 is a diagram showing a pattern transfer method using the 0th surface forming mold structure of FIG. 6A and the first surface forming mold structure of FIG. 6B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold structure 2 Board | substrate 3 Uneven part 3a Convex part 3b Concave part 10 0th surface formation mold structure 11 Electroformed layer 12 Magnetic layer 14 Slave disk 15 Substrate 16 Resist layer 17 0th surface master 18 Metal plate 101 0th Surface master 102 Mold structure for 0th surface formation 103, 203, 305 Concavity 104, 204, 301, 306 Projection 201 Master for first surface 202 Mold structure for first surface 301 Master for first surface 302 First Electrocasting master for one side 303 Mold structure for first side formation

Claims (6)

A method for producing a pair of mold structures used for forming recording / reproducing tracks on both sides of an information recording medium,
The pair of mold structures are patterned so that the trajectory corresponding to the recording / reproducing track of the information recording medium is substantially mirror-symmetrical between the first 0th surface and the other first surface of the information recording medium. A manufacturing method of a mold structure characterized by the above. A reversal pattern is formed by electroforming from the pattern of the master for the 0th surface to produce a mold structure for forming the 0th surface,
An electroformed master having a reversal pattern formed by electroforming from the pattern of the first surface master is formed, and a reversal pattern is further formed by electroforming from the pattern of the electroformed master. The manufacturing method of the mold structure of Claim 1 to produce.   The method for producing a mold structure according to claim 2, wherein the pattern of the master for the 0th surface and the pattern of the master for the first surface are substantially the same.   4. The method for producing a mold structure according to claim 2, wherein a positive resist material is used for pattern formation of the zeroth surface master and a negative resist material is used for pattern formation of the first surface master. 5.   The method for producing a mold structure according to any one of claims 1 to 4, wherein the information recording medium is any one of a discrete track medium, a patterned medium, an optical recording medium, and a magnetic transfer medium.   A mold structure manufactured by the method for manufacturing a mold structure according to claim 1.