Method for manufacturing disk device and disk device

Abstract

Provided are a method for manufacturing a disk device and a disk device, which are suitable for improving the yield of a self-servo writing process. According to one embodiment, a method of manufacturing a disk device is provided. A method of manufacturing a disk device includes acquiring information on a write width of a head. The manufacturing method of the disk device includes adjusting a seek speed of a head when writing a spiral pattern to the disk according to the acquired writing width.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2024-040859 (filing date: March 15, 2024), the entire contents of which are incorporated herein by reference. Technical Field

[0002] Embodiments of the present invention relate to a method for manufacturing a disk device and a disk device. Background Art

[0003] The manufacture of disk devices is sometimes carried out through a self-servo write process. In this process, a spiral pattern is written on the disk, and a servo pattern is written based on the spiral pattern. In order to reduce the manufacturing cost of disk devices, it is desirable to improve the yield of this self-servo write process. Summary of the Invention

[0004] Embodiments of the present invention provide a method for manufacturing a disk device and a disk device suitable for improving the yield of a self-servo writing process.

[0005] The disk device manufacturing method of the embodiment includes acquiring information on a head's writing width. The disk device manufacturing method includes adjusting a seek speed of the head when writing a spiral pattern on the disk based on the acquired writing width. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a flowchart illustrating a method for manufacturing a disk device according to an embodiment.

[0007] Figure 2 This is a diagram showing the configuration of a disk device in an embodiment.

[0008] Figure 3 1 is a diagram showing the arrangement of guide spiral patterns on a disk in an embodiment.

[0009] Figure 4 This is a diagram showing the format of control information in the embodiment.

[0010] Figure 5 This is a flowchart illustrating the adjustment process in the embodiment.

[0011] Figure 6 It is a diagram showing the arrangement of adjustment patterns on a disk in the embodiment.

[0012] Figure 7 It is a diagram showing the configuration of an adjustment pattern in the embodiment.

[0013] Figure 8 1 is a diagram showing a read signal of an adjustment pattern with respect to the offset SA1 in the embodiment.

[0014] Figure 9 1 is a diagram showing a read signal of an adjustment pattern with respect to the offset SA2 in the embodiment.

[0015] Figure 10 1 is a diagram showing a read signal of an adjustment pattern with respect to the offset SA3 in the embodiment.

[0016] Figure 11 This is a diagram illustrating a method for obtaining a write width in the embodiment.

[0017] Figure 12 This is a diagram showing a method for determining a seek speed in an embodiment.

[0018] Figure 13 FIG. 1 is a diagram showing a spiral pattern written at a slow seek speed in an embodiment.

[0019] Figure 14 This is a diagram showing a spiral pattern written at a medium seek speed in an embodiment.

[0020] Figure 15 This is a diagram showing a spiral pattern written at a fast seek speed in an embodiment.

[0021] Figure 16 1 is a diagram showing the arrangement of spiral patterns on a disk in an embodiment.

[0022] Figure 17 1 is a diagram showing a read signal of a spiral pattern in the embodiment.

[0023] Figure 18 FIG. 1 is a diagram showing the arrangement of servo patterns on a disk in an embodiment.

[0024] Description of Reference Numerals

[0025] 1: disk device, 10: disk, 11, 11_1 to 11_3: guide spiral pattern, 12: adjustment pattern, 13, 13_1 to 13_6: spiral pattern, 14, 14_1 to 14_7: servo pattern. DETAILED DESCRIPTION

[0026] Hereinafter, a method for manufacturing a disk device according to an embodiment will be described in detail with reference to the accompanying drawings. However, this embodiment does not limit the present invention.

[0027] (Implementation Method)

[0028] The manufacturing method of the disk device of the embodiment includes a self-servo writing process, but efforts have been made to improve the yield of the self-servo writing process. For example, the manufacturing method of the disk device 1 is as follows: Figure 1 As shown, it includes a blank disk writing (BDW) process and a self-servo writing (SSW) process. Figure 1 1 is a flowchart illustrating a method for manufacturing the disk device 1 .

[0029] In the BDW process (S1), a guide spiral pattern is written onto a blank disc. The written guide spiral pattern is then used to write a spiral pattern onto the disc. In the SSW process (S2), a servo pattern is written onto the disc using the written spiral pattern. This spiral pattern is also called a final spiral pattern. The servo pattern is also called a product servo pattern.

[0030] In the BDW process (S1), prepare Figure 2 The disk device 1 is as shown. Figure 2 It is a diagram showing the structure of the disk device 1.

[0031] Disk device 1 is connected to port PT of a manufacturing rack RC in manufacturing system 100 and can communicate with rack terminal RT via the manufacturing rack RC. Manufacturing system 100 may include multiple manufacturing racks RC. Each manufacturing rack RC has a rack interface (rack I / F) 101 and multiple platforms PL_1 to PL_k. k is an integer greater than or equal to 2. Each platform PL_1 to PL_k has a platform interface (platform I / F) 102 and multiple ports PT_1 to PT_n. n is an integer greater than or equal to 2. Each port PL is connected to connector 40 of disk device 1.

[0032] The disk device 1 is connected to the port PT during the manufacturing process, but can be connected to the host 2 after the manufacturing process is completed. The standard of the communication line between the disk device 1 and the host 2 is not limited to a specific standard. In one example, SATA (Serial Advanced Technology Attachment) or SAS (Serial Attached SCSI) can be used. The connector 40 can also include a SATA connector or a UART (Universal Asynchronous Receiver / Transmitter) connector. The disk device 1 functions as a storage medium for the host 2. The disk device 1 is, for example, a disk-type storage medium such as an HDD (Hard Disk Drive) or an optical drive.

[0033] The host 2 corresponds to, for example, a processor, a personal computer, or a server, etc. The disk device 1 can receive access commands (read commands and write commands) from the host 2 .

[0034] A disk drive 1 includes a plurality of disks 10 that rotate about a rotation axis 12 of a spindle motor (SPM) 11. Here, as an example, the disk drive 1 includes six disks 10-1, 10-2, 10-3, 10-4, 10-5, and 10-6. The six disks 10-1, 10-2, 10-3, 10-4, 10-5, and 10-6 are rotated integrally by the SPM 11.

[0035] Disk 10 is a roughly disc-shaped medium used to record information. Disk 10 can be a magnetic disk or a magneto-optical disk. If disk 10 is a magnetic disk, each of the six disks 10 has recording surfaces on the front and back surfaces where data can be recorded. In other words, the six disks 10 have 12 recording surfaces. To access each of the 12 recording surfaces, disk drive 1 includes 12 heads HD1 to HD12 corresponding to the 12 recording surfaces.

[0036] Head HD1 is positioned opposite the front surface of disk 10-1. Head HD2 is positioned opposite the back surface of disk 10-1. Head HD3 is positioned opposite the front surface of disk 10-2. Head HD4 is positioned opposite the back surface of disk 10-2. Head HD5 is positioned opposite the front surface of disk 10-3. Head HD6 is positioned opposite the back surface of disk 10-3. Head HD7 is positioned opposite the front surface of disk 10-4. Head HD8 is positioned opposite the back surface of disk 10-4. Head HD9 is positioned opposite the front surface of disk 10-5. Head HD10 is positioned opposite the back surface of disk 10-5. Head HD11 is positioned opposite the front surface of disk 10-6. Head HD12 is positioned opposite the back surface of disk 10-6.

[0037] Hereinafter, the twelve heads HD1 through HD12 will sometimes be collectively referred to as heads HD. Each head HD can access the recording surfaces of the six disks 10, i.e., write information and read data. Each head HD includes a write element WE and a read element RE. The write element WE writes information to the disks 10, and the read element RE reads information from the disks 10.

[0038] The disk drive 1 includes an actuator system 20 that integrally moves twelve heads HD. The actuator system 20 includes seven actuator arms 21, twelve suspensions 22, and a voice coil motor (VCM) 23. Each of the twelve suspensions 22 in the actuator system 20 supports one of the heads HD1 through HD12. Each of the twelve suspensions 22 in the actuator system 20 is attached to the tip of one of the seven actuator arms 21.

[0039] The actuator system 20 is rotatable about a rotation axis 24. The rotation axis 24 is positioned parallel to and spaced apart from the rotation axis 12. The VCM 23 is capable of rotating the actuator system 20 within a predetermined range about the rotation axis 24. This allows the actuator system 20 to move the heads HD1 to HD12 radially relative to the recording surfaces of the disks 10-1 to 10-6.

[0040] The disk device 1 further includes an SVC (Servo Controller) 31 , a head amplifier 32 , a nonvolatile memory 33 , a volatile memory 34 , a processor 35 , an RWC (Read Write Channel) 36 , and an HDC (Hard Disk Controller) 37 .

[0041] The head amplifier 32 supplies a signal corresponding to write data input from the RWC 36 to the head HD facing the recording surface to be written. The head amplifier 32 also amplifies a signal output from the head HD facing the recording surface to be read and supplies it to the RWC 36.

[0042] The nonvolatile memory 33 is, for example, a flash memory. The nonvolatile memory 33 stores programs executed by the processor 35. During the manufacturing process of the disk device 1, the programs executed by the processor 35 include the BDW program and the SSW program. After the manufacturing process of the disk device 1 is completed, the programs executed by the processor 35 include firmware for normal operation.

[0043] The volatile memory 34 is composed of volatile memory such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). The volatile memory 34 includes areas for buffering write data received from the host 2 before being written to the disk 10 and read data read from the disk 10 before being sent to the host 2.

[0044] The RWC 36 modulates the write data buffered in the volatile memory 34 and outputs the modulated data to the head amplifier 32 . The RWC 36 also demodulates the signal supplied from the head amplifier 32 and outputs the demodulated data to the HDC 37 .

[0045] During the manufacturing process of the disk device 1, the HDC 37 serves as a communication interface that enables communication with the port PT. Specifically, the HDC 37 can send predetermined requests to the rack terminal RT via the port PT, the platform I / F 102, and the rack I / F 101. Upon receiving the predetermined request, the rack terminal RT transmits response information in accordance with the predetermined request. The HDC 37 receives the response information from the rack terminal RT via the rack I / F 101, the platform I / F 102, and the port PT.

[0046] After the manufacturing process of the disk device 1 is completed, the HDC 37 is a communication interface that enables communication with the host 2. Specifically, when the HDC 37 receives a write command from the host 2, it stores the write data in the volatile memory 34 and returns a response to the host 2 when the write data to the disk 10 is completed. Furthermore, when the HDC 37 receives a read command from the host 2, it reads the data requested in response to the read command (read data) from the disk 10 and buffers it in the volatile memory 34. Thereafter, the HDC 37 returns the read data buffered in the volatile memory 34 to the host 2.

[0047] The SVC 31 supplies a control signal to the SPM 11 to rotate the SPM 11 at a predetermined frequency and phase. The control signal can be a control current or a control voltage.

[0048] In addition, the SVC 31 drives the VCM 23 so that the head HD moves to a position designated by the processor 35 .

[0049] The processor 35 is, for example, a CPU (Central Processing Unit) and executes various processes according to a program stored in a nonvolatile storage medium such as the nonvolatile memory 33 or the disk 10 .

[0050] For example, the processor 35 controls data writing and reading by the head HD, determines an access position on the recording surface of the disk 10 , and instructs the servo controller 31 on an access position.

[0051] The servo controller 31, the head amplifier 32, the nonvolatile memory 33, the volatile memory 34, the processor 35, the RWC 36, and the HDC 37 constitute the controller 30. However, the components of the controller 30 are not limited thereto.

[0052] return Figure 1 In the BDW process (S1), the disk device 1 writes the guide spiral pattern 11 to the blank disk 10 (S3).

[0053] The disk device 1 can write data to the recording surface of the corresponding disk 10 by any head HD among the plurality of heads HD1 to HD12. Figure 3 There are multiple guide spiral patterns 11_1 to 11_3 as shown. Figure 3 is a diagram showing the arrangement of the guide spiral pattern 11 on the disk 10. Figure 3 In FIG, the rotation direction of the disk 10 is indicated by a dashed arrow. Each guide spiral pattern 11 extends spirally from the inner circumference to the outer circumference of the disk 10. Figure 3 In the embodiment, the case where three guide spiral patterns 11_1 to 11_3 are written is exemplified, but the number of guide spiral patterns 11 may be 1 to 2, or may be 4 or more.

[0054] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at a first position on the inner circumference side according to the predetermined rotational speed. While rotating the disk 10 at the predetermined rotational speed, the disk drive 1 moves the head HD from the inner circumference to the outer circumference of the disk 10 at a predetermined seek speed (seeking) to a target position on the disk 10, and writes control information IF2 via the write element WE.

[0055] The disk device 1 can also write to the disk 10 Figure 4 Control information IF2 as shown. Figure 4 This figure shows the format of control information IF2. Control information IF2 includes Sync marks at a predetermined frequency, and basic Dibits are included between the Sync marks. Sync marks are used to adjust the seek speed, which will be described later. Basic Dibits are used to adjust the amplitude of the read signal.

[0056] Regarding the disk device 1, the control information IF2 is written in a spiral shape on the disk 10. As a result, the guide spiral pattern 11_1 is written on the disk 10.

[0057] Similarly, disk drive 1 controls head HD to a second position on the inner circumference side in accordance with a predetermined rotational speed. The second position is offset circumferentially from the first position by a predetermined amount. While rotating disk 10 at a predetermined rotational speed, disk drive 1 causes head HD to seek from the inner circumference to the outer circumference of disk 10 at a predetermined seek speed, and writes control information IF2 via write element WE. Consequently, guide spiral pattern 11_2 is written onto disk 10.

[0058] The disk drive 1 controls the head HD to a third position on the inner circumference side in accordance with a predetermined rotational speed. The third position is offset circumferentially from the second position by a predetermined amount. While rotating the disk 10 at a predetermined rotational speed, the disk drive 1 causes the head HD to seek from the inner circumference to the outer circumference of the disk 10 at a predetermined seek speed, and writes control information IF2 via the write element WE. This writes a guide spiral pattern 11_3 onto the disk 10.

[0059] In the BDW process ( S1 ), the disk device 1 performs an adjustment process ( S4 ) of tracking the guide spiral pattern 11 and adjusting the seek speed for writing the spiral pattern 22 .

[0060] In S4, Figure 5 The processing of S11 to S16 is shown. Figure 5 It is a flowchart showing the adjustment process (S4).

[0061] In S11, the disk device 1 uses the head HD of S3 to track the guide spiral pattern 11. The disk device 1 controls the head HD to be positioned at a predetermined cylinder on the inner circumference side based on information read from the guide spiral pattern 11 by the head HD of S3, and tracks the predetermined cylinder.

[0062] In S12, the disk device 1 writes the adjustment pattern 12 in the circumferential direction using the head HD other than the head HD in S3 (S12).

[0063] The disk device 1 may also write to the disk 10 using a head HD different from the head HD of S3 among the plurality of heads HD1 to HD12. Figure 6 The adjustment pattern 12 is shown. Figure 6 1 is a diagram showing the arrangement of the adjustment pattern 12 on the disk 10. Figure 6 In FIG. 1 , the adjustment pattern 12 is shown as extending in a partially missing circular shape in the circumferential direction of the disk 10. Figure 6 , the rotation direction of the disk 10 is indicated by a single-dot chain line.

[0064] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the fourth position on the inner circumference side based on information read from the guide spiral pattern 11. The fourth position may be slightly outer than the innermost circumference of the disk 10. While rotating the disk 10 at the predetermined rotational speed, the disk drive 1 writes control information IF2 via the write element WE without causing the head HD to perform a seek.

[0065] The disk device 1 controls the head HD to be positioned at the fourth position, and writes the control information IF2 in the circumferential direction on the disk 10 (see Figure 4 ). The disk device 1 may also write the control information IF2 in the circumferential direction in such a manner that the writing range of the control information IF2 is shorter than the amount of one circle. Figure 7 As shown, the adjustment pattern 12 is written on the disk 10 . Figure 7 1 is a diagram showing the structure of the adjustment pattern 12. Figure 7 In the figure, the vertical axis represents the radial position and the horizontal axis represents the circumferential position. Figure 7 In FIG. 1 , the rotation direction of the disk 10 is indicated by a dashed arrow, and the direction in which the writing element WE moves relative to the disk 10 is indicated by a dotted arrow.

[0066] Furthermore, the period of the Sync mark in the adjustment pattern 12 may be equal to the period of the Sync mark in the guide spiral pattern 11. The format of the adjustment pattern 12 may be equal to the format of the guide spiral pattern 11.

[0067] In S13, disk drive 1 performs partial reading using head HD in S12, changes the tracking position, and locates adjustment pattern 12. While tracking guide spiral pattern 11, disk drive 1 performs partial reading using read element RE of head HD in S12, changes the tracking cylinder, and locates adjustment pattern 12. The length of the reading time can be set by the length of time the read strobe remains active. The length of time the read strobe remains active can be set, for example, within a range that allows for continuous detection of a predetermined number of syncs or more. The predetermined number corresponds to the maximum amplitude of the read signal and can be, for example, 10. The number of readings can be set, for example, to 10 to 30 positions per revolution.

[0068] In S14, the readable offset range (writing width) of the adjustment pattern 12 found in S13 is measured. The readable offset range can also be expressed as the radial position range within which the adjustment pattern 12 can be read. "Readability" is, for example, determined as "the average number of syncs detected is above a limit level." The limit level is a number between 0 and a predetermined number, for example, 5.

[0069] For example, the disk device 1 controls the read element RE of the head HD to be positioned so as to be offset from the track center TC by an offset amount SA0 in the radial direction (see FIG. Figure 11 ). The offset SA0 corresponds to the case where the read element RE passes radially inward of the adjustment pattern 12. Although the disk drive 1 uses the read element RE to read the adjustment pattern 12, since it passes radially inward of the adjustment pattern 12, the resulting read signal level is almost zero, and this is detected as "the Sync number in the read signal is almost zero."

[0070] like Figure 8 As shown, the disk device 1 controls the read element RE of the head HD to be positioned at a radial position that is offset from the track center TC by an offset amount SA1 in the radial direction. Figure 8 1 is a graph showing the read signal of the adjustment pattern 12 with respect to the offset SA1. The offset SA1 is larger than the offset SA0, which corresponds to the case where the read element RE passes near the inner edge of the adjustment pattern 12. When the disk device 1 reads the adjustment pattern 12 with the read element RE, Figure 8 As shown, the obtained read signal has an amplitude in the + and - directions that is greater than a predetermined value, and is detected as "the number of Syncs in the read signal is greater than a limit level (eg, 10)".

[0071] like Figure 9 As shown, the disk device 1 controls the read element RE of the head HD to be positioned at a radial position that is offset from the track center TC by an offset amount SA2 in the radial direction. Figure 91 is a graph showing the read signal of the adjustment pattern 12 with respect to the offset SA2. The offset SA2 is larger than the offset SA1, which corresponds to the case where the read element RE passes near the radial center of the adjustment pattern 12. When the disk device 1 reads the adjustment pattern 12 with the read element RE, as shown in FIG. Figure 9 As shown, the obtained read signal has an amplitude in the + and - directions that is greater than a predetermined value, and is detected as "the number of Syncs in the read signal is greater than a limit level (eg, 10)".

[0072] like Figure 10 As shown, the disk device 1 controls the read element RE of the head HD to be positioned at a radial position that is offset from the track center TC by an offset amount SA3 in the radial direction. Figure 10 3 is a graph showing the read signal of the adjustment pattern 12 with respect to the offset SA3. The offset SA3 is larger than the offset SA2, which corresponds to the case where the read element RE passes near the edge of the outer periphery of the adjustment pattern 12. When the disk device 1 reads the adjustment pattern 12 with the read element RE, Figure 10 As shown, the obtained read signal has an amplitude in the + and - directions that is greater than a predetermined value, and is detected as "the number of Syncs in the read signal is greater than a limit level (eg, 10)".

[0073] The disk device 1 controls the read element RE of the head HD to be positioned so as to be offset from the track center TC by an offset amount SA4 in the radial direction (see FIG. Figure 11 ). Offset SA4 corresponds to the case where "the read element RE passes radially outside the adjustment pattern 12." Although the disk drive 1 uses the read element RE to read the adjustment pattern 12, since it passes radially outside the adjustment pattern 12, the resulting read signal level is almost zero, and "the Sync number in the read signal is almost zero" is detected.

[0074] according to Figures 8 to 10 The measurement results shown, such as Figure 11 As shown, the readable offset range (write width) can be obtained. Figure 11 This is a diagram showing a method for obtaining the write width.

[0075] Whether or not reading is possible is determined, for example, by assuming that the number of Syncs exceeding the limit level (e.g., 5) is detected on average. In measuring the readable offset range, the offset from the reference position is given in a scale of a predetermined width (e.g., 1 / 20 of the track width) to determine whether or not the adjustment pattern 12 can be read. The offset range (write width W) is calculated based on the difference between the maximum and minimum values ​​of the readable offset. WE ). Write width W WE Corresponds to the radial width of the writing element WE. Figure 11In the case of , the maximum and minimum values ​​of the offset that can be read are SA3 and SA1 respectively, and the write width W of the head HD is WE It can be obtained by the following mathematical formula 1.

[0076] W WE =SA3-SA1…Mathematical formula 1

[0077] In S15, the disk device 1 writes the width W WE The size of the spiral pattern 13 is such that the appropriate sync number can be ensured (see Figure 17 ) width, one is selected from a plurality of seek speeds prepared in advance. The appropriate Sync number is the Sync number that can control the positioning of the head HD with the required accuracy, and can be set to a limit level (for example, 5) or more. The disk device 1 can also select a Sync number based on the write width W. WE The size of Sync is selected from multiple seek speeds, and the fastest seek speed among the seek speeds with a Sync number above the limit level is selected.

[0078] The width of the spiral pattern 13 in the circumferential direction that can ensure an appropriate number of Syncs is obtained by calculating the length of one frame of the spiral pattern 13 (one Sync) x the appropriate number of Syncs. WE The width of the spiral pattern 13 in the circumferential direction corresponding to twice the width is referred to as the spiral width SP.

[0079] A plurality of candidate seek speeds and their corresponding write widths can be determined in advance through experiments. Figure 12 As shown, there is a tendency that "at a certain seek speed, the wider the write width of the write element WE, the greater the number of Syncs that can be read by the read element RE during demodulation." Figure 12 FIG. 1 is a diagram showing a method for determining the seek speed. Figure 12 In the figure, the vertical axis represents the number of frames of the spiral width SP, and the horizontal axis represents the write width. When the time of one frame length (Sync + basic Dibit) is set to T (sec), the seek speed during writing is set to V (m / sec), and the write width is set to W WE (nm), the number of frames F (count) of the spiral width is calculated by the following mathematical formula 2.

[0080] F=(2×W WE ×10 -9 ) / V / T…Mathematical formula 2

[0081] For example, three seek speeds V1, V2, and V3 satisfying the following equation 3 are prepared.

[0082] V1<V2<V3…Mathematical formula 3

[0083] At a relatively slow seek speed V1, if Figure 12 The writing width W of the writing element WE is shown by the dot-dashed line L1. WE The larger the value, the more linearly the number of Syncs that can be read by the read element RE during demodulation increases.

[0084] At a relatively fast seek speed V3, such as Figure 12 As shown by the two-dot chain line L3, the writing width W WE In a wider area, the writing width W of the writing element WE WE The larger the value, the more linearly the number of Syncs that can be read by the read element RE during demodulation increases.

[0085] At a moderate seek speed V2, if Figure 12 As shown by the solid line L2, the writing width W WE At a moderate degree of area variation, the writing width W of the writing element WE WE The larger the value, the more linearly the number of Syncs that can be read by the read element RE during demodulation increases.

[0086] When the appropriate Sync number is set to a limit level or above, prepare to respond to the " Figure 12 The intersection points of the straight lines L1 to L3 and the straight line L0 representing the limit level are the three writing widths W1, W2, and W3 that satisfy the following mathematical formula 4.

[0087] W1<W2<W3…Mathematical formula 4

[0088] For a relatively narrow write width W WE (For example, W1≤W WE <W2) head HD, such as Figure 12 As shown by the dot-dash line in FIG. 1 , the seek speed when writing by the write element WE of the head HD is set to a relatively slow V1. Figure 13 As shown, the inclination angle θ1 of the spiral pattern 13 relative to the circumferential direction is reduced. WE The spiral width SP1, which is twice as large as , satisfies the following mathematical formula 5.

[0089] SP1=2×W WE ×1 / (tanθ1)…Formula 5

[0090] As shown in Mathematical Formula 5, by writing in a narrow width W WE In the case of reducing the tilt angle θ1, the length of the spiral width SP1 can be set appropriately. As a result, the Sync number when the spiral pattern 13 is demodulated by the read element RE of the head HD can be increased (see Figure 17 ), which can improve the yield of the SSW process.

[0091] For a relatively wide write width W WE (For example, W3≤W WE ) head HD, the seek speed when writing through the write element WE of the head HD is set to a relatively fast V3, such as Figure 15 As shown, the inclination angle θ3 of the spiral pattern 13 relative to the circumferential direction is increased. WE The spiral width SP3, which is twice as large as , satisfies the following mathematical formula 6.

[0092] SP3=2×W WE ×1 / (tanθ3)…Formula 6

[0093] As shown in Mathematical Formula 6, by writing in a wide width W WE In this case, the inclination angle θ3 is increased to set the appropriate length of the spiral width SP3. This can suppress the degradation of positioning accuracy caused by the reduction in the number of spirals that can be demodulated when the length of the spiral pattern 13 demodulated by the reading element RE of the head HD in the time direction is too long.

[0094] For a medium write width W WE (For example, W2≤W WE <W3) head HD, the seek speed when writing by the write element WE of the head HD is set to a medium level V2, as shown in FIG. Figure 14 As shown, the inclination angle θ2 of the spiral pattern 13 relative to the circumferential direction is set to a medium degree. WE The spiral width SP2, which is twice as large as , satisfies the following mathematical formula 7.

[0095] SP2=2×W WE ×1 / (tanθ2)…Formula 7

[0096] As shown in Mathematical Formula 7, by writing at a moderate width W WE In the case of , setting the tilt angle θ2 to a moderate value allows for setting an appropriate spiral width SP3. This ensures an appropriate sync number and improves the yield of the SSW process. Furthermore, it suppresses the degradation of positioning accuracy caused by a reduction in the number of spirals that can be demodulated.

[0097] Figures 13 to 15 The spiral widths SP1 to SP3 shown satisfy the following mathematical formula 8.

[0098] SP1≈SP2≈SP3…Mathematical formula 8

[0099] By writing according to the width W WESeek speeds V1 to V3 are selected and set as tilt angles θ1 to θ3 so that the spiral widths SP1 to SP3 are all the same.

[0100] In addition, for a device with an excessively narrow write width W WE (For example, 0≤W WE The head HD of <W1) can also be treated as an error. This can avoid writing of the spiral pattern 13 with an insufficient number of Syncs.

[0101] like Figure 12 As shown, it is also possible to set a method for determining the write width W WE With a relatively narrow writing width W WE Correspondingly, W1≤W WE <W2 range WR1. With medium writing width W WE Correspondingly, W2≤W WE <W3 range WR2. With a relatively wide write width W WE Correspondingly, W3≤W WE Range WR3. With too narrow write width W WE Correspondingly, 0≤W is specified WE Range WR0 <W1.

[0102] If the writing width W measured in S15 WE If the write width W measured in S15 is included in the range WR1, the disk device 1 selects the seek speed V1 from among the plurality of seek speeds V1 to V3. WE If the write width W measured in S15 is included in the range WR2, the disk device 1 selects the seek speed V2 from among the plurality of seek speeds V1 to V3. WE If the data is included in the range WR3, the disk device 1 selects the seek speed V3 from among the plurality of seek speeds V1 to V3. This allows the seek speed to be appropriately adjusted according to the write width.

[0103] Furthermore, if the write width W measured in S15 WE If it is included in the range WR0, the disk device 1 may report it as an error and terminate the process.

[0104] In S16, the adjustment pattern 12 is erased. While tracking the guide spiral pattern 11, the adjustment pattern 12 is written by deflecting from the cylinder on which the adjustment pattern 12 is written. The frequency of the erasure pattern is, for example, an AC erasure pattern with a frequency four times the fundamental bit of the adjustment pattern 12. The writing range of the erasure pattern is, for example, ten circumferential revolutions. In the radial direction, an offset of 0.5 tracks is applied from the cylinder on which the adjustment pattern is written, and the writing is performed over a range of ±2 cylinders, erasing substantially all of the adjustment pattern.

[0105] Back to Figure 1 In the BDW process (S1), the guide spiral pattern 11 is tracked and the spiral pattern 13 is written at the seek speed adjusted in S4 (S5). The disk device 1 can also use the head HD to write to the recording surface of the corresponding disk 10. Figure 16 There are multiple spiral patterns 13_1 to 13_6 as shown. Figure 16 is a diagram showing the arrangement of the spiral pattern 13 on the disk 10. Figure 16 In FIG, the rotation direction of the disk 10 is indicated by a dashed arrow. Each spiral pattern 13 extends spirally from the inner circumference to the outer circumference of the disk 10. Figure 16 In FIG. 1 , the case where six spiral patterns 13_1 to 13_6 are written is exemplified, but the number of spiral patterns 13 may be 1 to 5, or may be 7 or more.

[0106] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the fifth position on the inner circumference side based on the information read from the guide spiral pattern 11_1. While rotating the disk 10 at the predetermined rotational speed, the disk drive 1 causes the head HD to seek from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_1 is written onto the disk 10.

[0107] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the sixth position on the inner circumference side based on the information read from the guide spiral pattern 11_1. While rotating the disk 10 at the predetermined rotational speed, the disk drive 1 causes the head HD to seek from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_2 is written onto the disk 10.

[0108] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the seventh position on the inner circumference side based on the information read from the guide spiral pattern 11_2. While rotating the disk 10 at the predetermined rotational speed, the disk drive 1 causes the head HD to seek from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_3 is written onto the disk 10.

[0109] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the eighth position on the inner circumference side based on the information read from the guide spiral pattern 11_2. While the disk drive 1 rotates the disk 10 at the predetermined rotational speed, the head HD seeks from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_4 is written onto the disk 10.

[0110] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the 9th position on the inner circumference side based on the information read from the guide spiral pattern 11_3. While the disk drive 1 rotates the disk 10 at the predetermined rotational speed, the head HD seeks from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_5 is written onto the disk 10.

[0111] The disk drive 1 rotates the disk 10 at a predetermined rotational speed and controls the head HD to be positioned at the 10th position on the inner circumference side based on the information read from the guide spiral pattern 11_3. While the disk drive 1 rotates the disk 10 at the predetermined rotational speed, the head HD seeks from the inner circumference side to the outer circumference side of the disk 10 at a seek speed of S4 and writes the control information IF2 through the write element WE. Figure 16 As shown, a spiral pattern 13_6 is written onto the disk 10.

[0112] Back to Figure 1 In the SSW process (S2), the spiral pattern 13 is tracked and the servo pattern 14 is written (S6). Figure 17 As shown, the disk device 1 reads the spiral pattern 13 by the read element RE of the head HD, and controls the write element WE of the head HD to be positioned at the eleventh position based on the information read from the spiral pattern 13 . Figure 17 13 is a diagram showing a read signal of the spiral pattern 13. The disk drive 1 rotates the disk 10 at a predetermined rotation speed while writing data via the write element WE of the head HD. Figure 18 Servo patterns 14_1 to 14_7 are distributed concentrically as indicated by the dotted lines in FIG. Figure 18 is a diagram showing the arrangement of the servo pattern 14 on the disk 10. Figure 18 In the embodiment, the case where seven servo patterns 14_1 to 14_7 are written is exemplified, but the number of servo patterns 14 may be 1 to 6, or may be 8 or more.

[0113] In this way, a plurality of concentric tracks are defined corresponding to the plurality of servo patterns 14_1 to 14_7 , and the disk device 1 equipped with the disk 10 including the plurality of tracks is manufactured.

[0114] As described above, in the embodiment, the disk drive 1 obtains information about the write width of the head HD, adjusts the seek speed of the head HD when writing a spiral pattern on the disk 10 based on the write width, and writes the spiral pattern on the disk 10 at the adjusted seek speed. This allows the inclination angle of the written spiral pattern relative to the circumferential direction to be set to an appropriate angle corresponding to the write width, thereby improving the manufacturing yield in the SSW process.

[0115] For example, for a relatively narrow write width W WE By setting the seek speed V1 to be relatively slow during writing and reducing the tilt angle θ1, the length of the spiral width SP1 can be set appropriately. This can increase the number of Syncs when the spiral pattern 13 is demodulated by the read element RE of the head HD while ensuring an appropriate number of Syncs (see Figure 17 ), which can improve the yield of the SSW process.

[0116] For a relatively wide write width W WE By setting the seek speed V3 during writing to a relatively fast one for the head HD and increasing the tilt angle θ3, it is possible to set an appropriate spiral width SP3. This can suppress the degradation of positioning accuracy caused by a decrease in the number of spirals that can be demodulated when the length of the spiral pattern 13 demodulated by the read element RE of the head HD in the time direction is too long.

[0117] For a medium write width W WE By setting the seek speed V2 and tilt angle θ2 during writing to a moderate head HD, the spiral width SP3 can be appropriately set. This ensures an appropriate number of syncs and improves the yield of the SSW process. Furthermore, it can suppress the degradation of positioning accuracy caused by a reduction in the number of spirals that can be demodulated.

[0118] Furthermore, the manufacturing information IF1 stored in the rack terminal RT may include information on the write width of the head HD in association with the identification information of the disk device 1. In this case, the disk device 1 may obtain the information on the write width of the head HD by receiving the information from the rack terminal RT via the communication line.

[0119] Specifically, in Figure 2In the disk drive 1 shown, the HDC 37 can send an acquisition request to the rack terminal RT via the port PT, the platform I / F 102, and the rack I / F 101, requesting information about the write width of the head HD. The acquisition request includes identification information of the disk drive 1 and a request to acquire information about the write width of the head HD. Upon receiving the acquisition request, the rack terminal RT refers to the manufacturing information IF1 based on the acquisition request and uses the identification information included in the acquisition request as a key to extract information about the write width of the head HD from the manufacturing method IF1. The rack terminal RT transmits the information about the write width of the head HD. Upon receiving the information about the write width of the head HD from the rack terminal RT via the rack I / F 101, the platform I / F 102, and the port PT, the HDC 37 stores the information about the write width of the head HD in the non-volatile memory 33.

[0120] In this case, the disk device 1 is Figure 1 In S4, instead of Figure 5 In S11 to S14, the process of receiving the information of the writing width of the head HD from the rack terminal RT via the communication line is performed, and then the process of S15 is performed. In addition, the process of S16 is omitted.

[0121] This simplifies the seek speed adjustment process ( S4 ), and reduces the time required for manufacturing the disk device 1 .

[0122] Alternatively, the writing width of the head HD may also vary depending on the writing conditions. In this case, the disk device 1 may change the writing conditions to write the adjustment pattern 12 and select a combination of writing conditions and seek speed that provides an appropriate number of Sync detections.

[0123] Specifically, in Figure 5 In S12, disk device 1 writes multiple adjustment patterns 12 corresponding to multiple write conditions onto disk 10. Under these multiple write conditions, the overshoot of the write current may vary. Overshoot refers to the magnitude of the current amplitude that fluctuates beyond the steady-state amplitude (DC amplitude) in the write current waveform. Multiple adjustment patterns 12 can be written onto different recording surfaces using different heads HD.

[0124] In the same manner as in the embodiment Figure 5 After S13, the disk device 1 Figure 5 In S14, the readable offset range (writing width) is measured for each of the multiple adjustment patterns 12 corresponding to the multiple writing conditions. The readable offset range can also be expressed as the radial position range within which the adjustment pattern 12 can be read. In S14, measurement results are obtained for multiple combinations of writing conditions and seek speeds. The number of combinations is (number of writing conditions) × (number of seek speed types).

[0125] exist Figure 5 In S15, the disk device 1 writes the width W WE The size of the spiral pattern 13 is selected from a variety of combinations to ensure the appropriate number of syncs (see Figure 16 The disk device 1 may select the fastest seek speed among a plurality of combinations at which the number of Sync detections is greater than or equal to the limit level.

[0126] This allows the tilt angle of the written spiral pattern with respect to the circumferential direction to be set to an appropriate angle according to the writing width and writing conditions, and further improves the manufacturing yield in the SSW process.

[0127] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These novel embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the gist of the invention. These embodiments and their variations are intended to be within the scope and spirit of the invention, and are within the scope of the invention set forth in the claims and their equivalents.

Claims

1. A method for manufacturing a disk device, comprising: Get the head write width information; and The seek speed of the head when writing a spiral pattern on a disk is adjusted based on the acquired write width.

2. The method for manufacturing a disk device according to claim 1, The process of obtaining the information includes: The information on the write width of the head is received from a system that manages the disk device via a communication line.

3. The method for manufacturing a disk device according to claim 1, The process of obtaining the information includes: The writing width of the head was measured.

4. The method for manufacturing a disk device according to claim 1, The process of adjusting the seek speed includes: corresponding to the obtained writing width being the first writing width, setting the seek speed of the head during writing to a first speed; and In response to the acquired writing width being a second writing width narrower than the first writing width, a seek speed of the head during writing is set to a second speed slower than the first speed.

5. The method for manufacturing a disk device according to claim 3, The process for performing the assay comprises: Writing an adjustment pattern on the disk in a circumferential direction; and A radial position range in which the adjustment pattern can be read is searched.

6. The method for manufacturing a disk device according to claim 5, The adjustment pattern includes a plurality of synchronization marks, The process of finding the position range includes: The adjustment pattern is read while the radial position of the second head is shifted from the track center relative to the disk, and a shift range is determined in which the number of synchronization marks included in the read signal exceeds a first threshold.

7. The method for manufacturing a disk device according to claim 6, The process of adjusting the seek speed includes: A width of a spiral pattern corresponding to a distance twice the offset range is determined for a plurality of seek speed candidates, and a seek speed having a width including a number of frames greater than a second threshold value is selected from the plurality of seek speed candidates.

8. The method for manufacturing a disk device according to claim 7, The process of selecting the seek speed candidate includes: The fastest seek speed is selected from one or more seek speed candidates in which the number of frames included in the width is greater than a second threshold value among the plurality of seek speed candidates.

9. The method for manufacturing a disk device according to claim 5, The process of performing the determination further comprises: The adjustment pattern is erased.

10. The method for manufacturing a disk device according to claim 3, The process for performing the assay comprises: writing an adjustment pattern in the circumferential direction of the disc under a plurality of writing conditions; and For each of the plurality of writing conditions, a radial position range in which the adjustment pattern can be read is searched. The process of finding the position range includes: The adjustment pattern is read while the radial position of the second head is shifted from the center of the track relative to the disk, and a shift range is determined for each of the plurality of write conditions in which the number of synchronization marks included in the read signal exceeds a first threshold value. The process of adjusting the seek speed includes: A spiral pattern width corresponding to a distance twice the offset range is determined for a plurality of seek speed candidates, and a combination of seek speed and writing conditions is selected in which the number of frames included in the width is greater than a second threshold value.

11. A disk device comprising: plate; an actuator to cause a head to seek relative to the disk; and The controller obtains information on the writing width of the head and adjusts the seek speed of the head when writing the spiral pattern on the disk based on the obtained writing width.

12. The disk device according to claim 11, The controller receives information on the write width of the head from a system that manages the disk device via a communication line.

13. The disk device according to claim 11, The controller obtains the information by measuring the writing width of the head.

14. The disk device according to claim 11, The controller adjusts the seek speed by setting the seek speed of the head during writing to a first speed corresponding to the obtained write width being the first write width, and setting the seek speed of the head during writing to a second speed slower than the first speed corresponding to the obtained write width being a second write width narrower than the first write width.

15. The disk device according to claim 13, The controller measures the writing width of the head by writing an adjustment pattern in the circumferential direction of the disk and searching for a radial position range where the adjustment pattern can be read.

16. The disk device according to claim 15, The adjustment pattern includes a plurality of synchronization marks, The controller searches the position range by reading the adjustment pattern while shifting the radial position of the second head relative to the disk from the track center and finding the shift range in which the number of synchronization marks included in the read signal exceeds a first threshold.

17. The disk device according to claim 16, The controller adjusts the seek speed by determining the width of the spiral pattern corresponding to a distance twice the offset range for a plurality of seek speed candidates, selecting a seek speed candidate whose width includes more frames than a second threshold value, and setting the selected seek speed candidate as the seek speed.

18. The disk device according to claim 17, The controller selects the seek speed candidate by selecting the fastest seek speed candidate from one or more seek speed candidates whose number of frames included in the width is greater than a second threshold value, and setting the fastest seek speed candidate as the seek speed.

19. The disk device according to claim 15, The controller erases the adjustment pattern.

20. The disk device according to claim 13, the controller, The writing width of the head is measured by writing an adjustment pattern on the disk in the circumferential direction under a plurality of writing conditions and searching for a radial position range where the adjustment pattern can be read for each of the plurality of writing conditions. The adjustment pattern is read while the radial position of the second head is offset from the center of the track relative to the disk, and the offset range in which the number of synchronization marks included in the read signal exceeds the first threshold is obtained for each of the plurality of write conditions, thereby finding the position range. A spiral pattern width corresponding to a distance twice the offset range is determined for a plurality of seek speed candidates, and a combination of seek speed and writing conditions is selected in which the number of frames included in the width is greater than a second threshold value.

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