JP2011076712A - Magnetic recording medium, and magnetic recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium, and a magnetic recording and reproducing device having a high positioning accuracy. <P>SOLUTION: In the magnetic recording medium including a pattern structure in which a servo area is composed of a recorded part and non recorded part, the servo area has a preamble part storing preamble information and an address part storing address information. A non-recording part is arranged between column patterns indicating the preamble information adjacent in the track direction in the preamble part while the non-recording part is arranged between column patterns indicating the address information adjacent in the track direction in the address part, and a total width of the pattern of the address part and the non-recording part is the same as a pitch of the preamble part in the circumferential direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention particularly relates to a patterned servo magnetic recording medium in which a servo portion is patterned by the presence or absence of a magnetic material or unevenness, and a magnetic recording apparatus including the magnetic recording medium.

  As the capacity of magnetic recording devices, magnetic disk devices, and hard disk drives increases, the recording density required for magnetic recording media increases. Therefore, the magnetic information recorded by the magnetic recording / reproducing head that moves relatively on the magnetic recording medium is likely to adversely affect the recording of adjacent tracks. In order to avoid this adverse effect, it has been considered to physically separate magnetic bodies in adjacent tracks. A medium in which the presence or absence of a magnetic material or a pattern of a magnetic material and a non-magnetic material is provided in the shape of a recording track or a recording bit on a magnetic recording medium is called a patterned medium.

  When the magnetic recording / reproducing head relatively moves on the surface of the magnetic recording medium, magnetic data is recorded / reproduced at a desired position on the surface of the medium.

  In order for the magnetic recording / reproducing head to move to a desired position on the recording medium, a positioning servo area exists on the magnetic recording medium. At the time of recording / reproducing, the position of the recording / reproducing head on the recording medium is grasped from the position signal obtained from the reproducing head when the recording / reproducing head crosses the servo area. Based on the obtained position information, the position of the recording / reproducing apparatus is controlled to move the recording head to a desired recording position.

  In the patterned medium, the servo area signal is also created as a magnetic pattern in a batch with the data area, which reduces the cost of producing the medium, and the servo positioning signal and the recording pattern are created in a batch. This is preferable in that high positional accuracy can be obtained. A medium in which the servo area is made as a magnetic pattern is particularly called a patterned servo medium.

  The patterned medium or the patterned servo medium is created using, for example, a nanoimprint process. For example, in a medium having a magnetic and non-magnetic pattern, a nanoimprint stamper having a concavo-convex pattern is pressed against a resist film coated on the magnetic film to transfer the concavo-convex pattern onto the resist film. Thereafter, the magnetic material under the resist film is patterned using the resist film to which the uneven pattern has been transferred as a mask. Therefore, the quality of the pattern shape of the magnetic material is affected by the quality of the concavo-convex pattern formed on the resist film.

  A magnetic pattern shape of a servo area used in a general HDD will be described.

  The servo area includes at least a preamble area, an address area, and a positioning burst area (or burst area).

  The address area has track number and sector number information and indicates the track position where the head is located. The address information is written in gray code so that data can be read even when the head is shifted to an adjacent track during seeking.

  A conventional address area pattern is shown in Patent Document 1. In the patterned servo medium, the pattern shown in FIG. 17 is created as a magnetic material and a non-magnetic material, or an uneven pattern of the magnetic material. In the conventional patterned servo medium, since the pattern indicating the address is adjacent in each digit, it has a stepped portion (inside the dotted line) as shown in FIG.

US Pat. No. 6,643,082

  However, in order to produce the address area on the patterned servo medium, a resist film having the pattern of FIG. 17 as an uneven structure must be produced by means such as a nanoimprint process. However, when the stepped portion shown in FIG. 17 is formed as an uneven pattern on the resist film as the address region, the edge portion of the stepped portion is deformed due to the surface tension of the resist, so as shown in FIG. There is a risk that the corners become dull. If the corner of the resist film is dull in the stepped portion, the dull shape is transferred in the magnetic pattern obtained in the subsequent process, and the recording / reproducing head is assembled after the medium is incorporated into the recording / reproducing apparatus. There is a possibility that the positioning accuracy will be reduced and the reproduction margin at the time of data reproduction will be reduced.

  An object of the present invention is to provide a magnetic recording medium and a magnetic recording / reproducing apparatus having high positioning accuracy in order to solve the above problems.

  The magnetic recording medium according to the embodiment is a magnetic recording medium including a pattern structure in which a servo area includes a recording part and a non-recording part. The servo area stores a preamble part in which preamble information is recorded and address information. A non-recording portion is arranged between digits of a pattern indicating preamble information existing adjacent to the track direction in the preamble portion, and address information existing adjacent to the track direction is stored in the address portion. The non-recording portion is arranged between the digits of the pattern shown, and the combined width of the address portion pattern and the non-recording portion is the same as the circumferential pitch of the preamble portion.

  A magnetic recording / reproducing apparatus according to the present invention includes the magnetic recording medium described above and a magnetic recording / reproducing head for reading servo information recorded in the servo area.

  According to the present invention, it is possible to obtain a magnetic recording medium and a magnetic recording / reproducing apparatus having an address structure that shows higher positioning accuracy than a magnetic recording medium having a conventional address structure.

It is a top view of the servo area | region in the magnetic recording medium of this invention. It is AA sectional drawing of FIG. It is AA sectional drawing of FIG. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 1 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a manufacturing-process figure of the magnetic-recording medium of Example 2 of this invention. It is a structure conceptual diagram of the magnetic recording / reproducing apparatus of Example 3 of this invention. It is a top view of the servo area | region of the conventional patterned servo medium. It is an enlarged view of the step-shaped part shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A plan view of a servo area in the magnetic recording medium of the present invention is shown in FIG. The servo area is roughly divided into a preamble section 10, an address section 20, and a deviation detection burst section (hereinafter referred to as a burst section) 30, and is formed as a recording / non-recording pattern as in the data area.

  The preamble section 10 performs PLL (Phase Locked Loop) processing that synchronizes the servo signal reproduction clock with respect to time deviation caused by rotational eccentricity of the media, and AGC (Auto Gain Control) processing that appropriately maintains the signal reproduction amplitude. Provided to do. The configuration is formed by a pattern that repeats in a recording / non-recording circumferential direction that is continuous in a substantially circular arc shape that is not divided in the radial direction. Further, each linear magnetic pattern is divided at a period according to the width and skew angle of the reproducing head.

  The address part 20 includes a non-recording part that separates patterns between adjacent digits in the address part 20. Servo signal recognition codes called servo marks, sector information, cylinder information, and the like are formed by Manchester codes at the same pitch as the circumferential pitch of the preamble portion. In particular, the cylinder information has a pattern in which the information changes for each servo track. Therefore, code conversion that minimizes the change between adjacent tracks called gray codes is used to reduce the influence of address misreading during seek operations. After that, it is recorded in Manchester code.

  The burst unit 30 is an off-track detection area for detecting the off-track amount from the on-track state of the cylinder address, and is a mark in which the pattern phase is further shifted in four radial directions called A, B, C, and D bursts Is formed. In each burst, a plurality of marks are arranged in the circumferential direction at the same pitch period as that of the preamble section 10, and the radial period is proportional to the address pattern change period, in other words, the period proportional to the servo track period. To be taken. In this embodiment, each burst is formed for 10 periods in the circumferential direction, and the radial direction has a pattern that repeats at a period twice as long as the servo track period. In addition, the mark shape is basically a square, strictly speaking, a parallelogram that takes into account the skew angle when accessing the head, but it is somewhat rounded due to stamping accuracy and processing performance such as transfer formation. Shape. The mark part is formed as a nonmagnetic part. Although the details of the principle of position detection from the burst unit 30 are omitted, the off-track amount is calculated by calculating the average amplitude value of each ABCD burst unit reproduction signal.

  2 and 3 are AA cross-sectional views of FIG. As shown in FIGS. 2 and 3, the address unit 20 has a pattern in which the recording unit 2 and the non-recording unit 3 are alternately repeated in the same manner as other portions. The recording unit 2 and the non-recording unit 3 are roughly divided into a magnetic body presence / absence pattern shown in FIG. 2 and a magnetic body irregularity pattern shown in FIG.

  In the pattern in the address section 20 of the present invention, each digit of the pattern is separated by the non-recording sections 2-2 and 3 as shown in FIG. Therefore, there is no stepped portion. Therefore, the dullness of the stepped pattern of the conventional magnetic recording medium as shown in FIG. 17 does not exist in the address pattern of the present invention. Therefore, in the magnetic recording / reproducing apparatus using the magnetic recording medium having the address pattern of the present invention, The above-described positioning accuracy problem does not occur, and the magnetic recording / reproducing head can be positioned with high accuracy.

  If the width of the non-recording portions 2-2 and 3 between each digit is too wide, the area of the address area is widened and the information recording area of the medium is compressed to reduce the recording capacity. In addition to the above-mentioned problem that occurs in the stepped part between the pattern and the pattern pitch becomes smaller, the pattern becomes dull due to the narrower aspect of the pattern. It is necessary to specify. Specifically, the combined width of the pattern (recording units 2 and 2-1) of the address unit 20 and the non-recording units 2-2 and 3 is preferably the same as the circumferential pitch of the preamble unit 10. The width of the separation portion is preferably 50% or more and 100% or less with respect to the pattern width of each digit of the address portion 20.

  First, a magnetic recording medium that is Embodiment 1 of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 and shows a pattern with and without a magnetic material.

  As shown in FIG. 2, in the pattern of presence / absence of magnetic material, the recording unit 2 has a magnetic material capable of recording / reproducing magnetic information by the magnetic recording / reproducing head, and the non-recording unit 3 records magnetic information by the recording / reproducing head. The reproducible magnetic film is thinner or not present than the thickness of the magnetic film of the recording part. A magnetic recording medium having such a pattern is called a magnetic material processing type medium. For example, in the case of a perpendicular recording magnetic recording medium, when the medium is magnetized in a direction perpendicular to the medium surface, magnetized information is obtained from the recording unit 2, but magnetization information is not obtained from the non-recording unit 3.

  Next, a method for manufacturing the magnetic recording medium of this embodiment will be described with reference to FIGS.

  First, as shown in FIG. 4, a resist 4 having a thickness of about 50 nm is applied on the substrate 1. The substrate 1 is preferably a Si substrate or a glass substrate. The resist 4 is a resist for electron beam drawing.

  Next, as shown in FIG. 5, the magnetic material pattern of the present invention is drawn as an electron beam and developed to form a magnetic material pattern as irregularities on the resist 4. At this time, the structure shown in FIG. 1 in which adjacent address patterns of the present invention are separated is formed. As described above, the separation width is preferably 50% to 100% with respect to the pattern width of each digit.

  After forming the magnetic material pattern, as shown in FIG. 6, the stamper 5 is obtained by electroforming the resist pattern obtained in FIG. The material of the stamper 5 is preferably Ni or an alloy thereof, but is not limited thereto. For example, metals such as Ti and Al, or alloys thereof, quartz, and the like can be given. The stamper unevenness is formed by transferring the resist unevenness in reverse. Although not shown, the stamper may be obtained by etching and transferring the surface of the substrate 1 corresponding to the unevenness of the resist.

  After the stamper 5 is formed, the resist 4 is removed as shown in FIG. 7, and a ferromagnetic layer 6 for magnetic recording is formed on the substrate 1 to a thickness of about 20 nm. The ferromagnetic layer 6 is preferably made of a material suitable for perpendicular recording, such as CoCrPt. Although not shown, it is preferable to form a base layer made of a soft magnetic material before forming the ferromagnetic layer 6. After the ferromagnetic layer 6 is formed, a resist for imprinting is applied thereon to about 40 nm to form a resist film 7.

  After forming the resist film 7, as shown in FIG. 8, the stamper 5 created in the process of FIG. 6 is opposed to the resist film 7, and the stamper 5 and the resist film 7 are pressed against each other based on the imprint method, The uneven pattern on the surface of the stamper 5 is transferred to the surface of the resist film 7. After the transfer, the stamper 5 is peeled off.

  After the concavo-convex pattern is transferred, as shown in FIG. 9, the lower ferromagnetic layer 6 is etched using the resist film 7 having the concavo-convex pattern formed by the process of FIG. The recording portion 2 is patterned according to the uneven pattern.

  Finally, a non-magnetic portion 3 is formed by forming a non-magnetic material in the concave portion between the recording portions 2, and the protective layer 8 made of DLC (Diamond-like Carbon) or the like is formed on the upper surface of the recording portion 2 and the non-recording portion 3. Although not shown, the lubricating layer is formed to complete the magnetic recording medium shown in FIG.

  With the above manufacturing method, a magnetic recording medium having a structure in which adjacent address patterns are separated is produced. Therefore, in this manufacturing method, there is no problem that the edge of the stepped portion of the address pattern becomes dull due to the deformation of the resist.

  Next, a magnetic recording medium that is Embodiment 2 of the present invention will be described with reference to FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1, like FIG. 2, and shows a pattern due to the unevenness of the magnetic material.

  In the concave / convex pattern of the magnetic material, as shown in FIG. 3, the recording portion 2 of the magnetic recording medium has a substrate convex portion 1-1 on which a magnetic material capable of recording and reproducing magnetic information by a magnetic recording / reproducing head is provided. It is formed. This portion is called a recording unit 2-1. The non-recording portion has a substrate recess 1-2, on which a magnetic material capable of recording / reproducing magnetic information is formed by a magnetic recording / reproducing head. This part is called a non-recording part 2-2. A magnetic recording medium having such a pattern is called a substrate processing medium. When this magnetic recording medium is incorporated in a magnetic recording / reproducing apparatus, the magnetic recording / reproducing head can record / reproduce magnetic information on the magnetic convex portion, but the magnetic concave portion is farther from the magnetic recording / reproducing head than the convex portion. Is long and magnetic information cannot be recorded / reproduced.

  Next, a method for manufacturing the magnetic recording medium of this embodiment will be described with reference to FIGS.

  The steps up to the creation of the stamper 5 (FIGS. 10 to 12) are the same as those in the manufacturing method of the first embodiment.

  After forming the stamper 5, the resist 4 is removed as shown in FIG. 13, and an imprint resist film 7 is newly applied on the substrate 1.

  After the resist film 7 is formed, as shown in FIG. 14, the stamper 5 created in the steps up to FIG. 12 is opposed to the resist film 7, and the stamper 5 and the resist film 7 are pressed against each other based on the imprint method. Then, the uneven pattern on the surface of the stamper 5 is transferred to the surface of the resist film 7. After the transfer, the stamper 5 is peeled off.

  After transferring the concavo-convex pattern, as shown in FIG. 15, the surface of the substrate 1 is made uneven by etching the lower substrate 1 surface using the resist film 7 having the concavo-convex pattern formed in the process of FIG. 14 as a mask. Patterned according to the pattern.

  Finally, as shown in FIG. 3, a ferromagnetic layer for magnetic recording is formed to a thickness of about 20 nm on the substrate 1 having an uneven surface. Among the formed ferromagnetic layers, the ferromagnetic layer formed on the substrate convex portion 1-1 becomes the recording portion 2-1, and the ferromagnetic layer formed on the substrate concave portion 1-2 is the non-recording portion 2-2. It becomes. The ferromagnetic layer is preferably made of a material suitable for perpendicular recording, such as CoCrPt. Although not shown, it is preferable to form an underlayer made of a soft magnetic material before forming the ferromagnetic layer. Then, a protective layer (not shown) made of DLC (Diamond-like Carbon) or the like and a lubricating layer (not shown) are formed on the upper surface of the recording unit 2-1, thereby completing the magnetic recording medium shown in FIG. .

  With the above manufacturing method, a magnetic recording medium having a structure in which adjacent address patterns are separated is produced. Therefore, as in the first embodiment, this manufacturing method does not cause a problem that the edge of the stepped portion of the address pattern becomes dull due to the deformation of the resist.

  Next, the configuration of the magnetic recording / reproducing apparatus of the present invention will be described with reference to FIG.

  FIG. 16 is a conceptual diagram of a configuration including one magnetic recording / reproducing head. The magnetic recording / reproducing apparatus of the present invention records and reproduces one magnetic recording medium on both the front and back surfaces of the magnetic recording medium with two magnetic recording / reproducing heads. Each is provided. The configuration of the magnetic recording / reproducing apparatus is basically the same as the conventional configuration except that the magnetic recording medium is the medium of the present invention.

  As shown in FIG. 16, the magnetic recording / reproducing apparatus of the present invention comprises a main body portion also called a head / disk assembly (HDA) 100 and a printed circuit board (PCB) 200.

(HDA)
As shown in FIG. 16, the HDA 100 includes a magnetic recording medium 140, a spindle motor (SPM) 150 that rotates the magnetic recording medium 140, a magnetic recording / reproducing head 110, a head moving mechanism, and a head amplifier (HIC) 120. Have.

  In the magnetic recording / reproducing head 110, a magnetic head element having a read element (magnetoresistance effect element; not shown) and a write element (not shown) is mounted on a slider (ABS; not shown) which is a head body. It is mounted on the head moving mechanism.

  The head moving mechanism includes a suspension arm 130 that supports the magnetic recording / reproducing head, a pivot shaft 139 that rotatably supports the suspension arm 130, and a voice coil motor (VCM) 131. The VCM 131 generates a rotational torque around the pivot shaft 139 in the suspension arm 130 to move the magnetic recording / reproducing head 110 in the radial direction of the magnetic recording medium. Further, an HIC 120 for amplifying an input / output signal of the magnetic recording / reproducing head 110 is fixed on the arm, and is electrically connected to the PCB 200 side by a flexible cable (FPC).

  In this embodiment, the HIC 120 is installed on the head moving mechanism in order to reduce the signal / noise ratio of the magnetic recording / reproducing head signal. However, the present invention is not limited to this. Also good.

  A magnetic recording medium 140 is mounted on a spindle motor (SPM) 150. As described above, the magnetic recording medium 140 is front and back, and is incorporated in the front and back directions in which the head movement locus of the magnetic recording / reproducing apparatus and the arc shape of the servo area pattern of the magnetic recording medium substantially coincide. Naturally, the specifications of the magnetic recording medium 140 satisfy the outer diameter and inner diameter suitable for the drive, the recording / reproducing characteristics, and the like, as in the prior art.

(PCB)
The PCB mainly includes four system LSIs. A disk controller (HDC) 210, a read / write channel IC 220, an MPU 230, and a motor driver IC 240.

  The MPU 230 is a control unit of the magnetic recording / reproducing apparatus drive system, and includes a ROM, a RAM, a CPU, and a logic processing unit (not shown) that realize the magnetic recording / reproducing head positioning control system according to this embodiment. The logic processing unit is an arithmetic processing unit configured by a hardware circuit and is used for high-speed arithmetic processing. The operation software (FW) is stored in the ROM, and the MPU 230 controls the magnetic recording / reproducing apparatus according to the FW.

  The HDC 210 is an interface unit in the magnetic recording / reproducing apparatus, exchanges information with the interface between the magnetic recording / reproducing apparatus and a host system (for example, a personal computer), the MPU 230, the read / write channel IC 220, and the motor driver IC 240. The entire recording / reproducing apparatus is managed.

  The read / write channel IC 220 is a head signal processing unit related to read / write, and includes a circuit that processes recording / reproduction signals such as channel switching of the HIC and read / write.

  Reconstruction of modulation method A for reading information A recorded in the pattern portion in the present invention, additional writing of information B using modulation method B in the pattern portion, and restoration of the recorded information B based on modulation method B Is performed in the read / write channel IC 220.

  The motor driver IC 240 is a drive driver unit of the VCM 131 and the SPM 150, and drives and controls the SPM 150 at a constant rotation, or supplies the VCM operation amount from the MPU 230 to the VCM as a current value to drive the head moving mechanism.

  As described above, in this embodiment, since the magnetic recording media shown in Embodiments 1 and 2 are used, higher positioning accuracy can be obtained compared with a magnetic recording / reproducing apparatus equipped with a conventional magnetic recording medium.

  For example, a magnetic recording medium having a servo pattern with a servo pitch of 200 nm on a 1.8 inch disk and having a conventional address structure, and a magnetic recording medium having the servo pattern and having the address structure of the present invention are prepared. Servo tracking accuracy was measured on a magnetic recording / reproducing device. The magnetic recording medium having the conventional address structure has a positioning accuracy of 3 nm and 10 nm, whereas the magnetic recording medium having the address structure of the present invention has a positioning accuracy of 3 nm and 7 nm. High positioning accuracy was shown compared to the recording medium.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2, 2-1 ... Recording part 2-2, 3 ... Non-recording part 4 ... Resist 5 ... Stamper 6 ... Ferromagnetic layer 7 ... Resist film 8 ... Protective layer 10 ... Preamble part 20 ... Address part 30 ... Burst Part
100 ... HDA
110 ... Magnetic recording / reproducing head 120 ... HIC
130 ... Suspension arm 131 ... VCM
139 Pivot shaft 140 Magnetic recording medium 150 SPM
200 ... PCB
210… HDC
220 ... Read / write channel IC
230 ... MPU
240 ... Motor driver IC

Claims (6)

  In a magnetic recording medium including a pattern structure in which a servo area includes a recording part and a non-recording part, the servo area has a preamble part in which preamble information is recorded and an address part in which address information is recorded, A non-recording portion is arranged between digits of a pattern indicating preamble information existing adjacent to the track direction in the preamble portion, and a non-recording portion is arranged between digits of a pattern indicating address information existing adjacent to the track direction in the address portion. The magnetic recording medium is characterized in that the combined width of the pattern of the address portion and the non-recording portion is the same as the circumferential pitch of the preamble portion.   2. The magnetic recording medium according to claim 1, wherein the width of the non-recording portion between patterns is 50% or more and 100% or less with respect to the width of the pattern of the address portion.   The magnetic recording medium according to claim 1, wherein the pattern is formed by a difference in film thickness of a magnetic recording layer in the magnetic recording medium.   The magnetic recording medium according to claim 1, wherein the pattern is formed by unevenness of a substrate in the magnetic recording medium.   5. A magnetic recording / reproducing apparatus comprising: the magnetic recording medium according to claim 1; and a magnetic recording / reproducing head for reading servo information recorded in the servo area.   6. The magnetic recording / reproducing apparatus according to claim 5, wherein the address information is formed by a gray code.

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