JP4551880B2 - Method for manufacturing magnetic recording medium - Google Patents

Description

The present invention relates to a magnetic recording medium, a recording / reproducing apparatus, and a method for manufacturing a magnetic recording medium.

  A patterned medium is a magnetic recording medium having a plurality of dot-shaped magnetic recording portions magnetically separated from each other, and typically a plurality of dot-shaped magnetic recording portions magnetically separated from each other by a nonmagnetic layer. Are arranged in the track direction. Magnetic recording devices using patterned media do not cause problems such as interference between recorded bits and thermal fluctuations that cannot be avoided in conventional magnetic recording devices that use a recording layer as a continuous film. It is expected that higher surface recording density can be realized.

  In order to record 1-bit information on one dot-shaped recording portion with this patterned medium, it is generally necessary that these dot-shaped recording portions are regularly arranged.

  One method for forming regularly arranged dot-shaped recording portions is a method using photolithography. However, when ultraviolet exposure is performed, ultrafine processing of 30 mm or less is difficult. In addition, although charged particle beam drawing and focused ion beam drawing enable fine processing, it is impractical to form a large number of dot-shaped recording portions by this method because the drawing time becomes long. is there.

  As another method for forming regularly arranged dot-shaped recording portions, a phenomenon in which a fine periodic structure is exhibited by phase separation of a block copolymer is used, and this is used as a mask template for processing a magnetic material to process magnetic films. There is a method for obtaining a separated magnetic dot array structure (Patent Document 1).

  Since this method forms island-like regions and sea-like regions using self-organization, an extremely fine pattern can be easily formed. However, the previous self-organization does not start from one place in the coating film but starts from a plurality of places. Under conditions where no external regulatory force is applied, the hexagonal lattice obtained as a result of self-organization starting from one location and the hexagonal lattice obtained as a result of self-organization originating from another location There is no correlation between the orientation directions. For this reason, regions having different hexagonal lattice orientation directions are generated in the coating film. That is, there are many defects and grain boundaries in the coating film, and practical recording and reproduction cannot be realized.

  Therefore, in order to use the pattern obtained by the arrangement of the self-organized particles as a recording bit of the patterned media, there is a method in which concentric or spiral concavo-convex grooves are provided on the surface of the recording disk and the self-organized particles are arranged along the grooves. Yes (Patent Document 2). By etching the magnetic film using the self-organized dots as a mask pattern, an array pattern of magnetic dots to which the shape of the dot pattern is transferred can be obtained, and these can be used as recording areas.

On the other hand, in order to position the recording / reproducing head in the recording area created using the self-organized arrangement, it is necessary to provide a servo area in an area different from the recording area. In this method, a self-organizing material is applied to the entire surface of the substrate, and a template is created using the obtained self-organizing dots as a mask pattern. Therefore, it is preferable in manufacturing that the servo area is also formed by the same method.
JP 2002-334414 A JP 2005-1000049 A

  The present invention has been made in view of the above circumstances, and a magnetic dot pattern in a recording area and a servo area is created simultaneously by using a self-organizing method using a block copolymer, and the magnetic dot pattern is formed in the recording area and the servo area. The present invention aims to provide a magnetic recording medium, a recording / reproducing apparatus, and a method for manufacturing the magnetic recording medium, in which the recording / reproducing head can accurately access the recording area from the servo area by arranging them regularly and reproducibly. .

  The magnetic recording medium of the present invention comprises a recording area for magnetically recording data and a servo area provided between the recording areas and having at least a burst portion for positioning the recording / reproducing head. A plurality of substantially square matrices are formed, and four or five magnetic dots are uniformly arranged in the matrix.

  Furthermore, the magnetic recording / reproducing apparatus of the present invention comprises the above magnetic recording medium, a read / write head, and a drive mechanism for moving the read / write head and the magnetic recording medium relative to each other when information is recorded and reproduced. Also good. Here, the sector turbo system records servo information such as a track positioning servo signal, a track address information signal, and a reproduction clock signal in the servo area of the magnetic recording medium, and the magnetic head uses this servo. In this method, the servo information is read by scanning the area to confirm and correct its own position.

  As described above, according to the present invention, a magnetic recording medium in which magnetic dot patterns in the recording area and the servo area are simultaneously created using a self-organizing arrangement method using a block copolymer, and the magnetic dot patterns in the servo area are regularly arranged. A recording / reproducing apparatus and a method for manufacturing a magnetic recording medium can be provided. Also, it is possible to provide a recording / reproducing apparatus that can accurately access each dot in the recording area of the reproducing head by regularly arranging the magnetic dot patterns in the servo area with good reproducibility.

  Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. Each figure is a schematic diagram showing an example of the present invention, and its shape, dimensions, ratio, etc. are different from actual magnetic recording media, etc., but these are appropriately designed using the following description and known techniques. Can change.

  The configuration of each area of the recording medium according to the embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic cross-sectional view in the direction of a track formed concentrically on the recording surface of a recording medium. As shown in FIG. 1, the recording medium has a servo area 1 necessary for positioning control of the magnetic recording head and a recording area 2 for storing data. The servo area 1 includes a preamble section 3, an address section 4 and a deviation inspection. A burst unit 5 (hereinafter referred to as a burst unit) is provided.

  FIG. 2 is a schematic plan view in the direction of tracks formed concentrically on the recording surface of the recording medium. In one embodiment of the present invention, a magnetic dot array is provided in the rectangle of FIG. 2, but the dot structure is omitted in FIG. In FIG. 2, the scale in the left-right direction is reduced to show the entire servo area, but the actual burst mark of the burst portion 5 and the bit shape of the address portion 4 are nearly square.

  The recording area 2 includes a recording track 6 having a magnetic dot array and a guard band 7 having a nonmagnetic material. Magnetic and non-magnetic patterns are formed in the preamble part 3, the address part 4 and the burst part 5 of the servo area 1.

  The pattern of the magnetic material is a pattern formed by an aggregate including a ferromagnetic material that changes the direction of magnetization by the magnetic field generated by the recording head and maintains the direction of magnetization even after the magnetic field of the recording head disappears. The recording area has information recording, and the servo area has the above functions. The material is an alloy containing a magnetic material such as Co or Fe, or a multilayer film.

The non-magnetic pattern is a material that is affected by the magnetic field of the recording head, and the magnetic field strength applied to the reproducing head is weaker than the magnetic pattern. There is a function to stably perform the sweep of the reproducing head on the recording medium. Specific examples include metal oxides such as SiO ₂ and AlO ₂ , nonmagnetic inorganic substances such as C and Ti, and organic substances such as polymers.

  The preamble section 3 is provided for performing PLL processing for synchronizing the servo signal reproduction clock with respect to time lag caused by rotational eccentricity of the recording medium and AGC processing for maintaining the signal reproduction amplitude appropriately. In the preamble portion 3, dot patterns of magnetic material are formed at regular intervals.

  In the address section 4, servo signal recognition codes (servo marks), sector information, track information, and the like are formed by Manchester codes at the same pitch as the circumferential pitch of the preamble section 3. In particular, since the track information has a pattern in which the information changes for each servo track, it is converted to a gray code that minimizes the change from the adjacent track so that the influence of address determination mistakes during seek operations is minimized. The Manchester code is recorded.

  The burst unit 5 is an off-track detection area for detecting the amount of off-track from the on-track state of the track address, and includes four types of marks (A, B, C, D bursts with the pattern phase shifted in the cross track direction). Called). In each burst, a plurality of burst marks are arranged in the circumferential direction at the same pitch as the preamble portion 3. The cycle in the cross track direction is proportional to the cycle (servo track cycle) at which the address pattern changes. Each burst mark is formed of an aggregate of magnetic dots, and surrounds the magnetic dots with a non-magnetic material. The off-track amount is calculated by calculating the average amplitude value of the reproduction signals of the A, B, C, and D bursts.

  As described above, in the embodiment of the present invention, the preamble part 3, the address part 4, the burst part 5 and the recording area 2 are aggregates of magnetic dots, and the magnetic dots in each area are formed by a method using a self-organizing material. Is done.

  FIG. 3 is a cross-sectional view for explaining a process of forming magnetic dots.

  FIG. 3A is a diagram showing a step of forming a guide for filling the self-organizing material. A magnetic layer 32 is formed on the surface of the substrate 31, a mask film 33 is formed on the magnetic layer 32, and then a resist 34 is formed by spin coating or the like. The resist 34 obtains a concave guide 35 by drawing and etching by an artificial drawing method. The material of the substrate 31 is preferably Si, glass, or quartz that can be etched. A known novolak type resist can be used as the resist film. In this embodiment, the magnetic dots are assumed to have a diameter of about 10 nm, the pitch between adjacent magnetic dots is about 25 nm, and the resist thickness is about 70 nm. The thickness of the magnetic layer is about 30 nm.

  FIG. 3B is a diagram showing a process of phase-separating the self-organizing material 35 by filling the guide 35 obtained in (A) with the self-organizing material 36 and performing an annealing process after removing the resist. It is. The phase separation structure in this step is composed of dot portions 37 arranged in a hexagonal lattice and a matrix portion 38 surrounding the dot portions 37.

  In this embodiment, PS (polystyrene) -PMMA (polymethyl methacrylate) diblock copolymer is assumed as the self-organizing material 36. The molecular weight ratio of the PS-PMMA diblock copolymer is, for example, when the pitch between the dots 37 is 26 nm, the PMMA molecular weight is 35500 with respect to the PS molecular weight of 12200, and the ratio is approximately PS25% and PMMA75%. At this time, a PS structure having a micelle structure and a low etching rate constitutes the dot portion 37, and PMMA having a high etching rate constitutes the matrix portion 38. The PS-PMMA diblock copolymer is dissolved in a suitable solvent such as toluene to form a film. Then, a phase separation structure is obtained by performing an annealing treatment at a temperature equal to or higher than the glass transition temperature of the PS-PMMA diblock copolymer. In this case, phase separation occurs in a nitrogen atmosphere at, for example, about 160 ° C. for about 10 hours.

  FIG. 3C is a cross-sectional view showing a process of transferring a pattern to the lower magnetic layer 32 using the self-organized material 36 having a phase separation structure in FIG. 3B as a mask. In the step of FIG. 3C, a pattern is formed on the magnetic layer 32 by performing etching based on the obtained phase separation structure. In this step, the hexagonal lattice array dot portions 37 become convex portions, and the matrix portions are removed from the magnetic layer 32 to become concave portions. Etching in this step is performed by applying an electric field of about 100 W in an atmosphere of about −20 ° C. and about 2 mTorr by RIE (reactive ion etching) using oxygen ions. At this time, RIE using CF4 as an etchant is also possible. Further, the self-organized material 39 left after etching forms the magnetic dots by etching the magnetic layer 32 by a magnetic material processing process such as Ar milling. In the step (C), when the etching resistance of the mask film 33 is low with respect to the remaining self-organized material 39, the magnetic layer other than the matrix portion 38, that is, the magnetic layer 41 outside the dot portion is etched. May be removed. In that case, only the magnetic material layer below the dot portion 37 is provided on the substrate 31, but the effect of the present invention is not affected if four or five magnetic dots are uniformly arranged.

  FIG. 3D is a cross-sectional view showing a process of forming a planarizing film 40 on the matrix portion formed in FIG. After the residue of the self-organizing material is removed by ashing, a planarizing film 40 is formed on the front surface of the substrate. The planarizing film 40 was formed by using a polymer such as SiO 2, carbon, alumina, PMMA, or PS to fill the matrix portion and polishing the surface.

  As described above, in a magnetic recording medium using a self-organizing material such as a block copolymer, it is necessary to form a guide structure corresponding to the matrix portion in the servo area and the recording area, and the shape of the guide becomes an array of magnetic dots. A big influence.

  FIG. 4 is a plan view showing an arrangement structure of magnetic dots. (A1), (B1) and (C1) in FIG. 4 show the length of the guide based on the pitch of the self-organized arrangement of the guide and the diblock copolymer. Further, (A2), (B2), and (C2) are dot arrangement structures after the diblock copolymer is filled in the guide and the processes of FIGS. 3 (A) to (D) are performed.

  In FIG. 4A1, for example, a substantially square guide having one side 2P is formed. When the block copolymer is filled in this guide, a structure consisting of four dots in which 2 rows × 2 rows of magnetic dots are arranged in the guide of (A1) in FIG. 4A2 in the film surface is obtained. In the diblock copolymer, two different polymers are linked to form one polymer. When the annealing treatment is performed, a micelle structure in which two types of polymers are aggregated with each other in the film is formed. That is, a structure is formed in which highly hydrophilic groups in the polymer aggregate to form a spherical shape and the outer surface thereof is covered with a highly hydrophobic group. Therefore, by adjusting the molecular weights of the two polymer parts, the diameter of the convex part and the pitch thereof can be adjusted in the structure after phase separation. In the case of FIG. 4 (A2), the pitch of the magnetic dots is P, which is substantially equal to the sum of the length of the hydrophilic group and the length of the hydrophobic group after layer separation. On the other hand, in a limited area inside the guide, the dot pattern does not necessarily form a hexagonal lattice, and has a structure in which dots are arranged as uniformly as possible in the area. Therefore, the magnetic dot pattern can be regularly arranged with good reproducibility, and a uniform burst mark can be formed.

  In FIG. 4 (B1), a square guide with one side of 2.5P is used. When the self-organized arrangement of the diblock copolymer is formed in this guide, as shown in FIG. 4 (B2), there are five dot arrangement structures in which two dots are arranged from one side of the guide, one by two, and so on. can get. The reason why this dot arrangement structure is obtained is that the guide is larger than the one side 2P guide used in FIG. 4 (A1). This is because it is necessary to form dots. The other dot position is formed at the center of the four dots, so that almost the entire guide surface can be filled. As a result, a structure consisting of a total of five dots in two, one, and two arrays is obtained. It is done.

    Note that the guide structure of FIG. 4B1 is the same as that of FIG. 4A1, and the same dot arrangement can be obtained in a plurality of adjacent guides. Therefore, as in FIG. 4A1, the magnetic dot pattern can be regularly arranged with good reproducibility, and a uniform burst mark can be formed.

  On the other hand, in FIG. 4 (C1), a substantially square structure with one side 3P is used as the guide structure. As a result of the phase separation of the diblock copolymer in this guide, as shown in FIG. 4 (C2), a total of 9 dot arrangement structure of 3 rows × 3 rows and 8 dots consisting of 3, 2, 3 An array structure is observed. The three, two, and three structures include a mixture of two dots arranged vertically and an array arranged horizontally. The reason why this dot arrangement structure can be obtained is that, when a 3 × 3 square lattice dot structure is formed in a square guide with a side of 3P, the filling rate is lower than that of the hexagonal lattice fine packing. The two-dot structure fills the space between the three dots at both ends, and the two dots have a larger size than the square dots in order to fill the surrounding space. In addition, the center dot of the three dot arrays at both ends moves slightly inward to fill the space between two large dots.

  In addition, in a substantially square guide with one side of 3P, the above-mentioned 3 × 3 structure, two by three structure, two in a horizontal direction and a total of three arrangements in a vertical direction are almost equally stable. When a plurality of guides are used, three arrays are randomly generated as shown in FIG. 4 (C2).

  As described above with reference to FIG. 4, depending on the shape of the guide and the molecular weight of the diblock copolymer, there are cases where the structures in the plurality of guides are the same or different in several types. If the dot structure in the guide is different, the signal shape at the time of positioning is different for each guide in the servo area obtained using this guide. In order to make the dot arrangement structure in the rectangular guide constant among the plurality of guides, a structure in which two dots are arranged on each side of the rectangular guide as shown in FIGS. 4 (A2) and 4 (B2). is necessary.

  In the present invention, as a structure for satisfying this condition, either the 2 × 2 structure shown in FIG. 4A2 or the two-by-two structure shown in FIG. Is used to create a magnetic recording medium.

(Example)
(Manufacture of recording media)
(1) A magnetic layer is formed by forming a Pd underlayer having a thickness of about 30 nm and a perpendicular magnetic recording material CoCrPt having a thickness of about 50 nm on a glass substrate having a side of 1 inch, and further forming a thickness on the magnetic layer. About 50 nm of SiO2 film was formed. A resist was spin-coated on the SiO2 film. A resist is processed by nano-imprinting lithography, and recording is made up of concave guides (outlined portions) having a width of 50 nm and a spacing of 120 nm arranged in parallel, as shown by the shaded portion in the schematic diagram of FIG. A resist pattern of a servo area formed by combining the area and a square guide (outlined part) having a side of 60 nm was formed. Using this resist pattern as a mask, the SiO2 film was etched by RIE until the magnetic layer was reached, and the guide was transferred to the SiO2 film. The guide formed in this way becomes a recording area and a servo area.

  (2) A block copolymer was embedded in the guide region to form a regular array structure of fine particles. First, the surface of the magnetic layer exposed on the bottom surface of the guide was hydrophobized with hexamethyldisilazane. Thereafter, the resist pattern residue was ashed. A solution in which a polystyrene-polybutadiene block copolymer (PS molecular weight Mw = 12000, PB molecular weight Mw = 35000) was dissolved in toluene at a concentration of 1% w / w was prepared. The solution was spin-coated on the sample, and the block copolymer was embedded in the guide region transferred to the SiO2 film. The sample was annealed in vacuum at 150 ° C. for 30 hours to order the block copolymer. As a result, as shown in FIG. 5B, the island-shaped polystyrene particles are surrounded by the sea-like polybutadiene portion, and in the burst portion of the servo region, the pitch between the centers of adjacent polystyrene particles in each guide is 30 nm. A periodically arranged structure was formed.

  (3) A recording cell was formed using the regularly arranged fine particles as a mask. The block copolymer was treated with ozone to remove the polybutadiene portion and then washed with water. Using the remaining polystyrene particles as a mask, the magnetic layer was etched by Ar ion milling to form a recording cell.

  (4) A matrix between recording cells was formed, and the surface was flattened. The residue of polystyrene particles was ashed. A SiO2 film having a thickness of about 50 nm was formed on the entire surface and embedded between the recording cells to form a matrix. The surface of the SiO2 film was polished and flattened by chemical mechanical polishing (CMP). Thereafter, diamond-like carbon was formed on the entire surface to form a protective film.

(Recording and playback device)
Next, an example of a recording / reproducing apparatus using a patterned medium magnetic recording medium in the embodiment of the present invention will be briefly described with reference to FIG.

  The hard disk shown in FIG. 6 has a main body called a head disk assembly (HDA) 100 and a printed circuit board 200 called PCB. The HDA 100 includes a patterned media disk 140 having a recording surface as shown in FIG. 1, a spindle motor (SPM) 150 that rotates the disk 140, a recording / reproducing head 110, head moving mechanisms 130, 131, and 139, as shown in FIG. Not have a head amplifier (HIC).

  The head 110 has a slider (ABS), which is a head body, mounted with a magnetic head element having a read element (GMR element) and a write element, and is mounted on a head moving mechanism. The head moving mechanism includes a suspension arm 130 that supports the head, a pivot shaft 139 that rotatably supports the suspension arm 130, and a VCM 131. The VCM 131 causes the suspension arm 130 to generate a rotational torque around the pivot shaft 139 to move the head in the radial direction of the disk 140. Further, a head amplifier (HIC) for amplifying the head input / output signals is fixed on the arm and electrically connected to the PCB 200 side by a flexible cable (FPC). In this embodiment, the HIC is installed on the head moving mechanism in order to reduce the SN of the head signal. However, the HIC may be fixed to the main body.

  The disk 140 can be recorded and reproduced on both front and back surfaces, and is incorporated in the front and back direction in which the head movement locus and the arc shape of the servo area pattern of the magnetic recording medium 140 substantially coincide. The specifications naturally satisfy the outer diameter, inner diameter, recording / reproducing characteristics, etc. that are suitable for recording / reproducing devices as in the past, but the servo area arc shape extends from the disk rotation center to the pivot center. It has a circular arc center on the circumference having the distance as a radial position, and the circular arc radius is given as a distance from the pivot to the magnetic head element.

  The PCB 200 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 a hard disk drive system, and includes a ROM, a RAM, a CPU, and a logic processing unit that realize a head positioning control system using a servo area of a patterned medium. 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 controls the drive according to the FW.

  The HDC 210 is an interface unit in the hard disk, and manages the entire drive by exchanging information with the interface between the disk drive and the host system (for example, a personal computer), MPU, read / write channel IC, and motor driver IC.

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

(Head positioning method)
Next, head positioning control will be briefly described with reference to FIG.

  FIG. 7 is a block diagram of the head positioning control, and C, F, P, and S represent system transfer functions, respectively. The control target P specifically corresponds to a head moving unit including a VCM, and the signal processing unit S is an element realized by a channel IC and an MPU (part of the off-track amount detection process is an MPU). is there.

  The control processing unit includes a feedback control unit C (hereinafter referred to as a first controller) and a synchronization suppression compensation unit F (second controller), and is specifically realized by an MPU.

  Although details of the operation in the signal processing unit S will be described later, the current track position (TP) information on the magnetic recording medium is obtained based on a reproduction signal including address information from the disk servo area immediately below the head position (HP). Generate.

  Based on the position error (E) between the target track position (RP) on the magnetic recording medium and the current position (TP) of the head on the magnetic recording medium, the first controller reduces the FB operation value in a direction in which the position error decreases. U1 is output.

  The second controller is an FF compensator for correcting the track shape on the magnetic recording medium, vibrations synchronized with the rotation of the magnetic recording medium, and the like, and stores the rotation synchronization compensation value calibrated in advance in the memory table. The second controller normally does not use the position error (E), and refers to a table based on servo sector information (not shown) given from the signal processing unit S and outputs it as an FF operation value U2.

  The control processing unit adds the first and second controller outputs U1 and U2, supplies the control operation value U to the VCM via the HDC, and drives the head.

  The synchronization compensation value table is calibrated during the initial operation, but when the position error (E) becomes greater than or equal to the set value, the recalibration process is started and the synchronization compensation value is updated.

(Location information detection processing method)
Next, how the position deviation is detected from the reproduction signal will be briefly described with reference to FIG.

  The magnetic recording medium is rotated at a constant rotation speed by SPM. The head is elastically supported via a gimbal provided on the suspension arm, and is designed to float so as to maintain a minute gap in balance with the air pressure accompanying the disk rotation. Thereby, the head reproducing element can detect the leakage magnetic flux from the disk magnetic layer with a certain magnetic gap.

  Due to this rotation, the servo area signal of the magnetic recording medium passes immediately below the head at a constant period. By detecting the track position information from the servo area reproduction signal, servo processing at a constant period can be executed.

  Once the HDC recognizes a servo area identification flag called a servo mark, the HDC can predict the timing at which the servo area comes directly under the head because of the fixed period. Therefore, the HDC prompts the channel to start servo processing at the timing when the preamble portion comes directly under the head.

  With reference to the block diagram of FIG. 8, the address reproduction processing unit in the channel will be briefly described. A reproduction output signal from a head amplifier IC (HIC) is read into a channel IC, subjected to analog filter processing (longitudinal signal equalization processing) by an equalizer, and sampled as a digital value by an analog digital converter (ADC).

  The leakage magnetic flux from the magnetic recording medium according to the present embodiment corresponds to a magnetic / non-magnetic pattern in a vertical magnetic field, but the high-pass characteristic of the head amplifier (HIC) and the longitudinal length of the equalizer at the front stage of the channel IC. By the equalization processing, the DC offset component is completely removed, and the output after the analog filter from the preamble portion is substantially a pseudo sine wave.

  In the channel IC, processing is switched according to the reproduction signal phase. Specifically, a synchronization pull-in process for synchronizing the reproduction signal clock with the media pattern period, an address interpretation process for reading sector / cylinder information, a burst part process for detecting the off-track amount, and the like are performed.

  Although details of the synchronization pull-in process are omitted, the AGC process is performed in which the ADC sampling timing is synchronized with the sine wave-like reproduction signal and the signal amplitude of the digital sample value is made to a certain level. The 1 and 0 periods of the media pattern are sampled at 4 points.

  In the address interpretation process, the sampling value is reduced in noise by FIR, and converted into sector information / track information by Viterbi composite processing based on maximum likelihood estimation or gray code inverse conversion processing. Thereby, the servo track information of the head can be acquired.

  Next, the channel shifts to an off-track amount detection process in the burst portion. Each signal amplitude is sample-and-hold integrated in the order of burst signal patterns A, B, C, and D, a voltage value corresponding to the average amplitude is output to the MPU, and a servo processing interrupt is issued to the MPU. Upon receiving this interrupt, the MPU reads each burst signal in time series by the internal ADC and performs a process of converting it to an off-track amount by the DSP. The servo track position of the head is accurately detected based on the off-track amount and the servo track information.

  With the above method, the recording / reproducing head in the magnetic recording medium positioned on the magnetic recording medium, and recording / reproducing was performed.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components 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 components disclosed in the embodiment. For example, you may delete a some component from all the components over embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

Sectional view of the magnetic recording medium according to the present embodiment Plan view of a magnetic recording medium according to the present embodiment The top view which shows the manufacturing process of the magnetic dot of the magnetic recording medium based on this embodiment The top view which shows the arrangement structure of the magnetic dot which concerns on this embodiment The top view which shows the matrix structure of the magnetic-recording medium based on this embodiment The block diagram which shows the recording / reproducing apparatus which concerns on this embodiment Block diagram of a head positioning control mechanism in the recording / reproducing apparatus according to the present embodiment Block diagram of an address reproduction processing unit in the recording / reproducing apparatus according to the present embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Servo area 2 ... Recording area 3 ... Preamble part 4 ... Address part 5 ... (Deviation inspection) Burst part 6 ... Recording track 7 ... Guard band 31 ... Substrate 32 ... Magnetic layer 33 ... Mask film 34 ... Resist 35 ... Guide 36 ... Self-organized material 37 ... Dot part 38 ... Matrix part 39 ... Self-organized material 40 left by etching ... Flattened film 100 ... Head disk assembly (HDA)
DESCRIPTION OF SYMBOLS 110 ... Head 130 ... Head moving mechanism 131 ... Head moving mechanism 139 ... Head moving mechanism 140 ... Magnetic recording medium 150 ... Spindle motor (SPM)
200 ... Printed circuit board (PCB)
210 ... Disk controller (HDC)
220 ... Read / write channel IC
230 ... MPU
240 ... motor driver IC 240

Claims (3)

A recording area for magnetically recording data;
A servo area provided between the recording areas and having at least a burst portion for positioning the recording / reproducing head;
A plurality of burst marks provided in the burst portion and having a plurality of magnetic dots ;
A method of manufacturing a sector servo magnetic recording medium comprising :
Forming a magnetic layer on the substrate;
Forming a mask film on the magnetic layer;
Forming a resist on the mask film;
The resist and the mask film are removed up to the surface of the magnetic layer by drawing and etching a part of the resist, and the burst mark having a substantially square shape whose one side is twice or 2.5 times the pitch of the magnetic dots. Forming a corresponding recess;
Removing the resist;
Filling the recess with a self-organizing material;
Separating the self-organized material by annealing the self-organized material; and
Etching the magnetic layer using the self-organized material separated as a mask to form magnetic dots; and
A method for producing a magnetic recording medium, comprising: The method of manufacturing a magnetic recording medium according to claim 1, wherein the number of the magnetic dots included in the burst mark is four . The method of manufacturing a magnetic recording medium according to claim 1, wherein the number of the magnetic dots included in the burst mark is five .

Images