JP2011248945A - Manufacturing method for resist master disk, imprint stamper for magnetic recording medium and magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a resist master disk with which a polygonal recess having an apex angle can be formed with high definition using electron beam lithography.SOLUTION: A manufacturing method of a resist master disk comprises: a step (1) for forming a photoresist layer on a circular substrate; a step (2) for radiating electron beams while rotating the substrate in one direction to draw multiple patterns on the photoresist layer; and a step (3) for processing the photoresist layer on which drawing is processed using a developer and converting the multiple patterns into multiple polygonal recesses. Each of the patterns drawn in the step (2) is a combination of at least one polygonal part and multiple point parts or line parts, and has a shape which is not similar to the polygonal recess in the step (3).

Description

  The present invention relates to a resist master, an imprint stamper for a magnetic recording medium, and a method for manufacturing a magnetic recording medium. More specifically, the present invention relates to a resist master having a polygonal pattern including a rectangle of 100 mm square or less, an imprint stamper for a magnetic recording medium, and a method for manufacturing a magnetic recording medium.

  As a method for regulating a preformat signal on a magnetic recording medium, a magnetic transfer method using a magnetic transfer master formed by applying an optical disc stamper manufacturing method has been proposed (see, for example, Patent Document 1). In this method, a resist layer formed on a substrate is irradiated with a laser or an electron beam, and the obtained concavo-convex pattern is replicated on the magnetic transfer master by electroforming or the like to produce a magnetic transfer master having the concavo-convex pattern. is doing. However, in the pattern formation with a laser beam, it is difficult to form a pattern of 300 nm or less due to the diffraction limit of light, and the current situation is that it cannot cope with the increase in magnetic recording density.

  Regarding this problem, a method of manufacturing a magnetic transfer master using an electron beam having a smaller beam diameter than that of a laser beam has been proposed (see Patent Document 2). In this method, one element (exposure area) of an uneven pattern is formed by scanning an electron beam having a beam diameter smaller than the minimum width of the element a plurality of times. For example, when forming a rectangular element extending in a direction perpendicular to the track direction (radial direction), scanning of the electron beam in the radial direction and micro-rotation of the substrate are alternately repeated a plurality of times, and one element is formed. The drawing for forming is performed.

  Even when a concavo-convex pattern is directly formed on a magnetic recording medium such as a hard disk, a concavo-convex pattern can be formed by rotating a circular substrate coated with a resist and irradiating a laser beam modulated according to information to be transferred. Conceivable. However, in a magnetic recording medium such as a hard disk, the track width has been narrowed to cope with the increase in recording density.

  As a technique for achieving high recording density of a hard disk, a so-called discrete type medium structure in which a magnetic part region that emits a magnetic signal is divided by a nonmagnetic part has been proposed (see Patent Document 3). A typical discrete type medium has a data zone including a plurality of data tracks, and a servo zone including a SAM area, a burst area, and the like. However, in the above proposal, it is not clearly shown how the discrete type medium structure is manufactured (see Patent Document 3).

  Furthermore, as an example of a method for producing a discrete type medium structure, a method including a step of transferring by an imprint method has been proposed (see Patent Document 4). In this proposed method, a stamper is formed from a master disk obtained by applying an electron beam lithography technique on a glass substrate, and the stamper is applied to an imprint method. However, there is no specific description of the electron beam lithography technique for forming the master.

  Regarding the formation of the concavo-convex pattern using an electron beam, a method has been proposed in which the substrate is rotated in one direction and at the same time the electron beam is vibrated (scanned) with a constant amplitude in the radial direction (see Patent Document 5). In addition, a method of scanning an electron beam so as to draw a periodic waveform along an axis parallel to the track direction (circumferential direction) has been proposed (see Patent Document 6). Furthermore, a method including a step of irradiating an electron beam while a translational and rotational movement of a disk-shaped substrate coated with a resist has been proposed (see Patent Document 7). In this proposal, the deflection amount of the irradiated electron beam is changed so as to draw a concentric circle every rotation, and the exposure image at the place exposed once is partially overlapped with the exposure image after the next rotation.

  In the above proposal relating to a method for producing a discrete-type medium structure, the shape of an exposure image for obtaining a rectangular pattern is similar to the obtained pattern. There has been no specific proposal regarding a method for forming a rectangular pattern of 100 nm square or less formed in the burst region 230 of the servo zone 200 by drawing a shape that is not similar to the desired pattern shape.

  Further, a resist having a discontinuous fine pattern is formed on a single crystal substrate using electron beam exposure, and then anisotropic etching is performed to form a linear pattern dissimilar to the aforementioned discontinuous fine pattern. A method for manufacturing a diffraction grating structure has been proposed (see Patent Document 8). This method forms a continuous linear pattern by matching the anisotropic direction of etching and the arrangement direction of the discontinuous fine pattern, and is not applicable to the formation of a rectangular pattern of 100 nm square or less. Absent.

JP 2001-256644 A JP 2003-091806 A JP 2004-110896 A JP 2003-157520 A JP 2004-164856 A Japanese Patent Application Laid-Open No. 2004-1778736 JP 2006-1000066 A JP-A-9-167758

  When a resist master for forming a discrete type medium including a concave-convex pattern extending concentrically or spirally in the track direction (circumferential direction) is produced by electron beam drawing, the servo zone increases as the desired recording density increases. It is difficult to form a burst region. Specifically, as the recording density increases, it is necessary to form a polygonal pattern of 100 nm square or less in the servo area. However, when an electron beam is uniformly irradiated over the entire rectangular area similar to the desired rectangular pattern, the concave portion of the resulting resist layer becomes a substantially circular (dot) shape due to the proximity effect of the electron beam. . The proximity effect of the electron beam is due to the reflection of the electron beam by the substrate (backscattering) and / or the scattering of the electron beam in the resist layer (forward scattering), and the periphery of the portion irradiated with the electron beam is exposed to the electron beam. It means that it will be in the state. The proximity effect is particularly remarkable in a portion where electron beams are densely irradiated. When the electron beam is uniformly irradiated on the entire rectangular pattern, the central portion of each side of the rectangle is most significantly affected by the proximity effect, and the proximity effect at each vertex is minimized. As a result, the central part of each side expands outward and a substantially circular recess is obtained.

  Here, when the electron beam is irradiated to a rectangular pattern that gives a rectangular recess having a desired size when it is assumed that the proximity effect of the electron beam does not exist, the actually obtained recess is substantially larger than the desired size. It becomes a circular shape. When a discrete type medium is formed using this resist master, each of the magnetic parts in the burst area of the servo zone has a size larger than a desired size. The enlargement of the magnetic part in the burst region may interfere with normal writing / reading with respect to the magnetic recording medium due to miss reading of information such as the track position. On the other hand, when the rectangular pattern irradiated with the electron beam is reduced in consideration of the proximity effect of the electron beam, the size of the obtained recess is within a desired range, but the shape remains substantially circular. When a discrete medium is formed using this resist master, the signal output of each magnetic part in the burst area of the servo zone is lowered. This is because the formed substantially circular magnetic part has a smaller volume than the desired rectangular magnetic part. In this case as well, normal writing / reading on the magnetic recording medium may be hindered.

  Accordingly, it is an object of the present invention to provide a method of manufacturing a resist master capable of precisely forming a polygonal concave portion of 100 nm square or less corresponding to a magnetic part in a burst region of a servo zone of a magnetic recording medium. is there. It is another object of the present invention to provide an imprint master for a magnetic recording medium and a method for the magnetic recording medium using the obtained resist master.

The method of manufacturing the resist master disk according to the first embodiment of the present invention is as follows.
(1) forming a photoresist layer on a circular substrate;
(2) drawing a plurality of patterns on the photoresist layer by irradiating an electron beam while rotating the substrate in one direction;
(3) processing the patterned photoresist layer using a developer to convert the plurality of patterns into a plurality of polygonal recesses, and each of the patterns drawn in step (2) is It is a combination of at least one polygonal part and a plurality of point-like parts or linear parts, and has a shape that is not similar to the polygonal concave part in the step (3). Here, it is desirable to arrange a plurality of dotted portions or linear portions in the step (2) on the bisector of the apex angle of each vertex of the polygonal portion. Furthermore, in the step (2), it is desirable to accelerate the electron beam with an acceleration voltage of 50 to 100 kV.

A method of manufacturing an imprint stamper for a magnetic recording medium according to the second embodiment of the present invention is as follows:
(4) forming a resist master using the method described in the first embodiment;
(5) forming a metal layer on the surface having the plurality of polygonal concave portions of the resist master using an electroforming method;
(6) removing the resist master and forming an imprint stamper.

A method of manufacturing a magnetic recording medium according to the third embodiment of the present invention includes:
(7) forming an imprint stamper using the method described in the second embodiment;
(8) A step of preparing a magnetic recording medium having at least a magnetic recording layer, wherein the magnetic recording layer is the outermost surface of the magnetic recording medium;
(9) forming a resist layer on the magnetic recording layer;
(10) pressing the imprint stamper against the resist layer to form a patterned resist layer;
(11) Etching the magnetic recording layer in a pattern using the patterned resist layer as a mask;
It is characterized by including.

  According to the present invention, when a resist master for forming a discrete medium including a concavo-convex pattern extending concentrically or spirally in the track direction (circumferential direction) is formed, it is formed in the burst region of the servo zone. A polygonal pattern having a maximum inscribed circle diameter of 100 nm or less can be finely formed. Moreover, the imprint master for magnetic recording media can be produced using the obtained resist master. Furthermore, a high-quality magnetic recording medium can be manufactured using the imprint master.

It is a figure which shows the pattern of a discrete track medium. It is a figure explaining the electron beam drawing process of a prior art, (a) is a figure which shows the pattern of electron beam drawing, (b) is a figure which shows the recessed part obtained after a image development process, (c) is obtained. It is a figure which shows the SEM observation image of the surface of the obtained resist original disc. It is a figure explaining the electron beam drawing process of the method of this invention, (a) is a figure which shows the pattern of electron beam drawing, (b) is a figure which shows the recessed part obtained after a image development process, (c) FIG. 5 is a view showing an SEM observation image of the surface of the obtained resist master. It is a figure which shows the detail of the electron beam drawing process using a rotation stage.

The method of manufacturing the resist master disk according to the first embodiment of the present invention is as follows.
(1) forming a photoresist layer on a circular substrate;
(2) drawing a plurality of patterns on the photoresist layer by irradiating an electron beam while rotating the substrate in one direction;
(3) processing the patterned photoresist layer using a developer to convert the plurality of patterns into a plurality of polygonal recesses, and each of the patterns drawn in step (2) is It is a combination of at least one polygonal part and a plurality of point-like parts or linear parts, and has a shape that is not similar to the polygonal concave part in the step (3). Polygons in the present invention include triangles, quadrangles (rectangles, squares, etc.), pentagons, hexagons, and the like. The polygon in the present invention preferably has an apex angle having an angle of 90 degrees or less.

  FIG. 1 shows a typical example of a discrete type medium structure. The discrete type medium includes a data zone 300 and a servo zone 200. In the data zone 300, there is a data track 310 which is a magnetic part region divided by non-magnetic parts. on the other hand. The servo zone 200 is classified into a SAM area 210, a preamble area 220, and a burst area 230, and an appropriate patterned magnetic part is formed in each of these areas. In the method of the first embodiment of the present invention, a polygonal magnetic part (preferably a rectangular magnetic part with a 100 nm square or less) whose maximum inscribed circle has a diameter of 100 nm or less is formed in the burst region 230. An object of the present invention is to provide a resist master that can be used. Note that the maximum inscribed circle that defines the dimensions of the polygon need not be inscribed on all sides of the polygon. For example, in the case of a rectangle, it is desirable that the diameter of a circle in contact with the three sides (that is, the short side of the rectangle) be 100 nm or less.

  In step (1), a photoresist layer is formed on the circular substrate. The circular substrate can be formed using any material known in the art, such as a silicon wafer, a glass substrate, or a ceramic substrate. In addition, the photoresist layer is made of any positive electron beam photoresist material known in the art (such as ZEP-520 manufactured by Nippon Zeon Co., Ltd.) using any technique known in the art. It can be formed by attaching to a substrate.

  In step (2), while rotating the circular substrate on which the photoresist layer is formed in one direction, an electron beam is irradiated to draw a plurality of patterns on the photoresist layer.

  As shown in FIG. 3A, each of the patterns 10 drawn on the photoresist layer in the step (2) is a combination of at least one polygonal portion 11 and a plurality of dot-like portions or linear portions 12. Has a shape. This shape is not similar to the polygonal concave portion obtained in the step (3). Here, it is desirable to arrange a plurality of dotted portions or linear portions 12 on the bisector of the apex angle of each vertex of the polygonal portion 11. The dimensions of the polygonal part 11 and the dimensions of the plurality of dot-like parts or linear parts 12 are determined depending on the material of the circular substrate and photoresist layer used, the beam diameter and intensity of the electron beam used, and the like. .

  FIG. 4 shows one pattern drawn on the photoresist layer. As shown in FIG. 4, each of the polygonal portion 11 and the plurality of point-like portions or line-like portions 12 is an aggregate of a plurality of drawing points 14. For example, scanning is performed with an electron beam in the radial direction (vertical direction in FIG. 4) of the circular substrate, and drawing is performed at the position of the required virtual drawing center line 16 to form one row of drawing points 14. Here, by turning on / off the electron beam by blanking control, it is possible to accurately irradiate the target virtual drawing center line 16 with the electron beam. Next, the circular substrate is slightly rotated in the circumferential direction. The step (2) can be performed by alternately repeating the electron beam scanning step and the circular substrate micro-rotation step.

  In the step (2), it is preferable to use an electron beam accelerated at an acceleration voltage of 50 to 100 kV. The influence of forward scattering can be reduced by setting the acceleration voltage of the electron beam to 50 kV or higher, and the influence of backscattering can be reduced by setting the acceleration voltage to 100 kV or lower, thereby enabling fine pattern drawing.

  In step (2), by increasing the pitch for irradiating the electron beam (pitch between the drawing points), the dose amount in the minimum feed amount of the electron beam scanning in the radial direction of the circular substrate can be reduced. Conversely, by performing electron beam irradiation a plurality of times at the same drawing point, the dose amount in the minimum feed amount of the electron beam scanning in the radial direction of the circular substrate can be increased.

  Subsequently, in the step (3), the patterned photoresist layer is processed using a developer, so that the plurality of patterns 10 shown in FIG. 2A are converted into a plurality of polygons shown in FIG. It converts into the shape recessed part 20. FIG.

  Here, the plurality of dot-like parts or line-like parts 12 compensate for the proximity effect of the electron beam at the apex of the polygonal part 11 which is insufficient as compared with the central part of each side of the polygonal part 11, as shown in FIG. A polygonal recess 20 as shown in (b) is provided. The obtained polygonal recess 20 can be used to manufacture the magnetic part of the burst region 230 of the servo zone 200 in the manufacture of the discrete medium shown in FIG. Alternatively, in the production of bit patterned media in which the recording bits that are the minimum units of magnetic recording in the data zone are independent from each other, the polygonal recess 20 can be used for the production of the recording bits in the data zone. .

  Optionally, subsequent to the treatment with the developer, washing with a rinsing solution may be performed to remove the residue of the photoresist material peeled from the photoresist layer. Further, after treatment with a developing solution or cleaning with a rinsing solution, drying may be performed using any means (such as air blow) known in the art.

A method of manufacturing an imprint stamper for a magnetic recording medium according to the second embodiment of the present invention is as follows:
(4) forming a resist master using the method described in the first embodiment;
(5) forming a metal layer on the surface having the plurality of polygonal concave portions of the resist master using an electroforming method;
(6) removing the resist master and forming an imprint stamper. Here, step (4) can be carried out as described above.

  In the step (5), first, a conductive film for use in an electroforming method may be formed on a photoresist layer in which a polygonal concave portion of a resist master is formed. The conductive film can be formed by depositing any metal known in the art such as nickel on the photoresist layer using a technique such as sputtering, vapor deposition, or electroless plating. .

  Subsequently, the resist master on which the conductive film is formed is immersed in an electroforming bath, and electroforming is performed by passing an electric current using the conductive film as a cathode to form a metal layer. The electroforming bath may contain any solution known in the art such as, for example, nickel sulfamate plating solution, Watt solution, wood solution, black nickel plating solution.

  Electroforming can be performed for a time sufficient to obtain a metal layer of the desired thickness, depending on the current flow.

  Subsequently, in step (6), the resist master is removed to form an imprint stamper made of a metal layer. The resulting imprint stamper has an uneven surface that is a reverse image of the resist master. The removal of the resist master can be carried out using conventional means. Further, in order to remove the resist residue on the imprint stamper, cleaning by oxygen plasma ashing, electrolytic cleaning, or the like may be performed.

A method of manufacturing a magnetic recording medium according to the third embodiment of the present invention includes:
(7) forming an imprint stamper using the method described in the second embodiment;
(8) A step of preparing a magnetic recording medium having at least a magnetic recording layer, wherein the magnetic recording layer is the outermost surface of the magnetic recording medium;
(9) forming a resist layer on the magnetic recording layer;
(10) pressing the imprint stamper against the resist layer to form a patterned resist layer;
(11) Etching the magnetic recording layer in a pattern using the patterned resist layer as a mask;
(12) A step of removing the patterned resist layer. Here, step (7) can be carried out as described above.

  In step (8), a magnetic recording medium is prepared. The magnetic recording medium that can be used in the present invention has at least a magnetic recording layer formed on a substrate. The outermost surface of the magnetic recording medium prepared in this step is preferably a magnetic recording layer. This is because the magnetic recording layer is patterned in the step (11) described later. Alternatively, an underlayer, an intermediate layer, and the like for controlling the crystallinity and orientation of the magnetic recording layer material may be provided between the substrate and the magnetic recording layer. When the magnetic recording medium is for performing perpendicular magnetic recording, a soft magnetic backing layer for concentrating the perpendicular next time on the magnetic recording layer may be provided between the substrate and the magnetic recording layer. Each of the aforementioned layers can be formed using any material and technique known in the art.

  In step (9), a resist layer is formed on the magnetic recording layer that forms the outermost surface of the magnetic recording medium. The resist layer can be formed of any material that can form irregularities by imprinting in the step (10) described below and has sufficient etching resistance for use as a mask in the step (11). Also, a resist layer can be formed by attaching a resist material to the magnetic recording layer using any technique known in the art. The resist layer formed in this step desirably has a uniform film thickness over the entire surface of the magnetic recording layer (magnetic recording medium).

  In step (10), the imprint stamper formed by the method of the second embodiment is pressed against the resist layer to transfer the irregularities, thereby forming a patterned resist layer. Optionally, a release agent may be applied in advance to the unevenness forming surface of the imprint stamper. In this step, in order to facilitate the transfer of unevenness from the imprint stamper to the resist layer, at least one of the resist layer (magnetic recording medium) or the imprint stamper may be heated. The pressing pressure in this step can be appropriately selected depending on the resist layer material used, the presence or absence of heating, and the like. The imprint stamper is pressed for a time sufficient to transfer the irregularities at a given temperature and pressure condition, and then the imprint stamper is separated from the resist layer. Here, a thin layer of the resist material may remain on the bottom surface of the recess of the resist layer. As long as the position and width of the convex portion of the resist layer are maintained, a dry etching process such as oxygen plasma ashing for removing the thin layer of the resist material may be performed. Alternatively, although depending on the etching conditions in the step (11), the step (11) may be performed while the thin layer of the resist material remains.

  In step (11), the magnetic recording layer is etched using the patterned resist layer as a mask. Although depending on the materials used for the resist layer and the magnetic recording layer, this step can be performed using a technique such as reactive ion etching (RIE). In this step, at least a part of the magnetic recording layer is removed to form a plurality of magnetically independent portions including a burst pattern of the servo zone in the magnetic recording layer. Further, when the magnetic recording medium includes a layer other than the magnetic recording layer, even if a layer other than the magnetic recording layer is etched in this step as long as a plurality of magnetically independent portions are formed in the magnetic recording layer. Good.

  After completion of the step (11), the patterned resist layer may be removed as necessary. The removal of the resist layer can be performed by a dry etching technique such as oxygen plasma ashing. Furthermore, if necessary, a layer such as a protective layer or a lubricating layer may be formed on the magnetic recording layer etched into a pattern.

(Comparative Example 1)
Resist ZEP-520 manufactured by Nippon Zeon Co., Ltd. was diluted 4-fold with anisole to prepare a coating solution. The obtained coating solution was applied to a 6-inch diameter silicon wafer substrate using a spin coating method, and then pre-baked at 180 ° C. for 2 minutes to produce a substrate having a resist layer with a thickness of 50 nm.

  The obtained substrate is transported to a predetermined position in the electron beam drawing apparatus, and a pattern shown in FIG. 2A is drawn under vacuum using an electron beam having an acceleration voltage of 50 kV, a beam current of 20 pA, and a beam diameter of 1.5 nm. Went. More specifically, an electron beam was uniformly applied to the inside of a square pattern 110 of 20 nm square alternately arranged for each column at a vertical and horizontal pitch of 100 nm. Subsequently, development was performed by immersing the drawn substrate in a developer for 15 seconds. Furthermore, the substrate after development was immersed in a rinse solution for 30 seconds, washed, and dried by air blowing to obtain a resist master having a circular recess 120 having a diameter of about 30 nm as shown in FIG. FIG. 2C shows an SEM observation image of the surface of the obtained resist master.

  Here, the electrons irradiated to the substrate surface during electron beam drawing are scattered (forward scattered) in the resist and reflected (back scattered) from the substrate. The intensity distributions of forward scattering and back scattering are normal distributions having different dispersions. The amount of electron beam energy per unit area (dose amount) accumulated in the resist layer at a given site is the sum of the amount of energy by direct electron beam irradiation and the amount of energy of the two types of scattering. Therefore, the portion of the resist layer that was not directly irradiated with the electron beam was also exposed to the electron beam. Therefore, even if a polygonal (square or the like) pattern 110 is drawn using an electron beam with a thin beam diameter, the concave portion 120 actually formed after development has a larger area, forming a polygonal concave portion having a vertex. In general, when the accelerating voltage is 50 kV, it is difficult to form a polygonal recess of 50 nm square or less.

Example 1
A substrate having a resist layer with a thickness of 50 nm was produced by the same procedure as in Comparative Example 1.

  The obtained substrate was transported to a predetermined position in the electron beam drawing apparatus, and a plurality of patterns 10 were drawn under vacuum using an electron beam having an acceleration voltage of 50 kV, a beam current of 20 pA, and a beam diameter of 1.5 nm. . Here, as shown in FIG. 3A, each of the drawn patterns 10 is a polygonal portion 11 having a square shape of 20 nm square, which is alternately arranged for each column at a vertical and horizontal pitch of 100 nm. And a dot-like portion or linear portion 12 having a length of 20 nm extending from each vertex of the polygonal portion 11 in the direction of the bisector of the apex angle. Further, as shown in FIG. 4, the pattern 10 was drawn by repeating the scanning of the electron beam in the radial direction of the substrate and the minute rotation of the substrate.

  The drawn substrate was processed using the same method as in Comparative Example 1 to obtain a resist master having a recess 20 formed in the resist layer as shown in FIG. The obtained recess 20 had a size of 50 nm square. FIG. 3C shows an SEM observation image of the surface of the obtained resist master. As is apparent from FIG. 3C, the recesses in the resist layer of the obtained resist master were desired squares with apex angles formed.

  The obtained resist master was transported into a film forming chamber of a sputtering apparatus, and nickel was deposited on the resist layer having the irregularities by a sputtering method to form a conductive film having a thickness of 4 nm. Next, a resist master having a conductive film formed on the surface thereof was immersed in a nickel sulfamate plating solution, and electroformed over 120 minutes using the conductive film as a cathode to form a metal layer having a thickness of 30 μm. Subsequently, the resist master is removed, the resist residue remaining on the conductive film is removed using an oxygen plasma ashing method, the central portion of the conductive film and the metal layer is removed by punching, and the conductive film and the metal layer are removed. An annular imprint stamper having a multilayer structure was obtained.

(Example 2)
The drawing technique described in the first embodiment is used in the burst area 230 of the servo zone 200, and the conventional drawing method is used in the other parts (the data zone 300, the SAM area 210 and the preamble area 220 of the servo zone 200). A resist master having a concavo-convex pattern as shown in FIG. 1 was prepared. In this embodiment, each of the patterns 10 drawn in the resist layer region corresponding to the burst region 230 is divided into a polygonal portion 11 having a square of 50 nm square and a bisection of the apex angle from each vertex of the polygonal portion. It was comprised with the four linear parts 12 of length 20nm extended in a line direction. The concave portion of the resist layer obtained after the development process had a square shape of 80 nm square.

  By applying the method described in Example 1 to the obtained resist master, an annular imprint stamper was obtained.

  Subsequently, a magnetic recording medium having the magnetic recording layer as the uppermost layer was separately manufactured. A resist layer was formed on the magnetic recording layer. The uneven surface of the imprint stamper obtained above was pressed against the resist layer to obtain a patterned resist layer. Further, the magnetic recording layer is etched using the patterned resist layer as a mask, so that a desired magnetic portion (including data tracks in the data zone 300, bursts in the burst region 230, etc.) is magnetically independent discrete track media. Obtained.

10 Pattern 11 Polygonal part 12 Point or line part 14 Drawing point 16 Virtual drawing center line 20 Polygonal concave part 110 Pattern 120 Concave part 200 Servo zone 210 SAM area 220 Preamble area 230 Burst area 300 Data zone 310 Data track

Claims (5)

(1) forming a photoresist layer on a circular substrate;
(2) drawing a plurality of patterns on the photoresist layer by irradiating an electron beam while rotating the substrate in one direction;
(3) processing the patterned photoresist layer using a developer to convert the plurality of patterns into a plurality of polygonal recesses, and each of the patterns drawn in step (2) is A method for producing a resist master, which is a combination of at least one polygonal portion and a plurality of point-like portions or linear portions, and has a shape that is not similar to the polygonal concave portion in step (3).   The resist master disc according to claim 1, wherein the plurality of dotted portions or linear portions in step (2) are arranged on a bisector of an apex angle of each vertex of the polygonal portion. Method.   The method of manufacturing a resist master according to claim 1, wherein in the step (2), the electron beam is accelerated with an acceleration voltage of 50 to 100 kV. (4) forming a resist master using the method according to any one of claims 1 to 3, and
(5) forming a metal layer on the surface having the plurality of polygonal concave portions of the resist master using an electroforming method;
(6) A method of manufacturing an imprint stamper for a magnetic recording medium, comprising: removing the resist master and forming an imprint stamper. (7) forming an imprint stamper using the method according to claim 4;
(8) A step of preparing a magnetic recording medium having at least a magnetic recording layer, wherein the magnetic recording layer is the outermost surface of the magnetic recording medium;
(9) forming a resist layer on the magnetic recording layer;
(10) pressing the imprint stamper against the resist layer to form a patterned resist layer;
(11) Etching the magnetic recording layer in a pattern using the patterned resist layer as a mask;
A method for manufacturing a magnetic recording medium, comprising: