WO2013100154A1 - Procédé de fabrication d'un substrat en verre de disque magnétique - Google Patents

Procédé de fabrication d'un substrat en verre de disque magnétique Download PDF

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Publication number
WO2013100154A1
WO2013100154A1 PCT/JP2012/084234 JP2012084234W WO2013100154A1 WO 2013100154 A1 WO2013100154 A1 WO 2013100154A1 JP 2012084234 W JP2012084234 W JP 2012084234W WO 2013100154 A1 WO2013100154 A1 WO 2013100154A1
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WO
WIPO (PCT)
Prior art keywords
polishing
base plate
glass base
glass
wall surface
Prior art date
Application number
PCT/JP2012/084234
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English (en)
Japanese (ja)
Inventor
裕樹 中川
京介 飯泉
健太 岩間
剛太郎 吉丸
Original Assignee
Hoya株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to CN201280064360.7A priority Critical patent/CN104011795B/zh
Priority to JP2013551871A priority patent/JP5661950B2/ja
Publication of WO2013100154A1 publication Critical patent/WO2013100154A1/fr

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
    • B24B37/044—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor characterised by the composition of the lapping agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/07—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
    • B24B37/08—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for double side lapping

Definitions

  • the present invention relates to a method for producing a glass substrate for a magnetic disk.
  • a personal computer or a DVD (Digital Versatile Disc) recording device has a built-in hard disk device (HDD: Hard Disk Drive) for data recording.
  • HDD Hard Disk Drive
  • a hard disk device used in a portable computer such as a notebook personal computer
  • a magnetic disk in which a magnetic layer is provided on a glass substrate is used, and the magnetic head slightly floats above the surface of the magnetic disk.
  • magnetic recording information is recorded on or read from the magnetic layer.
  • a glass substrate is preferably used because it has a property that it is less likely to be plastically deformed than a metal substrate (aluminum substrate) or the like.
  • the density of magnetic recording has been increased.
  • the magnetic recording information area (recording bit) is miniaturized by using a perpendicular magnetic recording method in which the magnetization direction in the magnetic layer is perpendicular to the surface of the substrate.
  • the storage capacity of one disk substrate can be increased.
  • the distance from the magnetic recording layer is extremely shortened by further protruding the recording / reproducing element portion of the magnetic head, thereby further improving the accuracy of information recording / reproducing (S / N). To improve the ratio).
  • Such control of the recording / reproducing element portion of the magnetic head is called a DFH (Dynamic Flying Height) control mechanism, and a magnetic head equipped with this control mechanism is called a DFH head.
  • DFH Dynamic Flying Height
  • a magnetic head equipped with this control mechanism is called a DFH head.
  • the surface irregularity of the substrate is extremely small in order to avoid collision and contact with the magnetic head and the recording / reproducing element portion protruding further therefrom. It is made to be smaller.
  • the process for producing the glass substrate for magnetic disks includes a grinding process in which the main surface of the glass base plate that has become flat after press molding is ground with fixed abrasive grains, and scratches remaining on the main surface by this grinding process.
  • the main surface polishing step is included for the purpose of removing strain.
  • a method for manufacturing a glass substrate for a magnetic disk using cerium oxide (cerium dioxide) abrasive grains as an abrasive is known (Patent Document 1).
  • the main surface is polished (first polishing) using cerium oxide as free abrasive grains, and then the glass base plate is chemically strengthened. .
  • zirconia zirconium dioxide
  • a magnetic disk is produced by forming a magnetic layer on a glass substrate produced by using the above zirconia as a polishing material for free abrasive grains of a glass base plate, compared with a glass substrate produced by using cerium oxide as an abrasive.
  • problems such as a head crash failure and a thermal asperity failure are relatively frequent.
  • the present invention provides a magnetic disk glass that is less prone to problems such as head crash failure and thermal asperity failure when a glass substrate for magnetic disk is produced by polishing using zirconia abrasive as an abrasive for loose abrasive grains. It aims at providing the manufacturing method of the glass substrate for magnetic discs which can manufacture a board
  • the inventors of the present application are to investigate the cause of problems such as head crash failure and thermal asperity failure in a glass substrate for magnetic disk produced by polishing using zirconia abrasive as an abrasive for loose abrasive.
  • the main surface of the glass substrate has zirconia particles adhering to the main surface during the formation of the magnetic layer, even after the main surface is sufficiently cleaned and the particles are removed after polishing with a mirror finish.
  • a magnetic layer is laminated above the zirconia particles, and minute irregularities are formed on the surface of the magnetic layer.
  • the minute irregularities cause problems such as a head crash failure and a thermal asperity failure.
  • the zirconia particles adhering to the main surface of the glass substrate are part of the zirconia abrasive grains used for polishing and are likely to adhere to the outer peripheral surface and inner peripheral surface of the glass substrate.
  • abrasive grains such as cerium oxide and silica were used as an abrasive, but came to occur when zirconia abrasive grains were used.
  • cleaning method which removes effectively the zirconia particle adhering to the glass substrate is not established.
  • “adhering” means, for example, that zirconia particles are stuck and fixed to the side wall surface of the glass base plate.
  • the term “attach” means, for example, that the zirconia particles simply remain on the main surface of the glass base plate, and that the zirconium particles adhere to the side wall surface of the glass base plate. It may be understood to mean.
  • the inventors of the present application consider the reason why zirconia particles may adhere to the main surface when the magnetic layer is formed even if the main surface is sufficiently washed and particles are removed. Yes. In other words, even if zirconia particles remain on the glass base plate by main surface polishing with zirconia abrasive grains, the zirconia particles remaining on the main surface are removed by final polishing on the main surface, but on the side wall surface of the glass base plate. Residual or adhered zirconia particles are not removed by subsequent cleaning of the glass base plate.
  • the zirconia particles adhere to the side wall surface of the glass base plate by the glass base plate contacting the carrier during polishing. Conceivable.
  • the main surface polishing is performed by holding the glass base plate on the carrier in this way, the zirconia particles are fixed as a cause for the zirconia particles to adhere to the glass base plate.
  • the polishing pad is pressed against the glass base plate with a much stronger force, and the surface plate and carrier are rotated (relative to the polishing pad at a higher rotational speed than when cerium oxide is used).
  • the reason for performing main surface polishing under such severe conditions is that the cerium oxide abrasive grains were used under the same conditions as when cerium oxide abrasive grains were used. This is because the processing rate is significantly reduced.
  • the zirconia particle adhering to the side wall surface will detach
  • the side wall surface of the glass base plate or the magnetic disk glass substrate is gripped in the process so as not to deteriorate the surface properties of the main surface. It is considered that the particles are detached.
  • one aspect of the present invention is a method of manufacturing a glass substrate for a magnetic disk having a pair of main surfaces and a side wall surface orthogonal to the pair of main surfaces, and the disk-shaped glass base plate is held by a carrier
  • the main surface of the glass base plate is sandwiched between polishing pads, a polishing liquid having zirconia particles as abrasive grains is supplied between the glass base plate and the polishing pad, and the polishing pad and the glass base plate are relative to each other.
  • Another aspect of the present invention is a method of manufacturing a glass substrate for a magnetic disk having a pair of main surfaces and a side wall surface orthogonal to the pair of main surfaces, the disk-shaped glass base plate being held by a carrier
  • the main surface of the glass base plate is sandwiched between polishing pads, a polishing liquid having zirconia particles as abrasive grains is supplied between the glass base plate and the polishing pad, and the polishing pad and the glass base plate are relative to each other.
  • an end surface polishing step for polishing the side wall surface is a method of manufacturing a glass substrate for a magnetic disk having a pair of main surfaces and a side wall surface orthogonal to the pair of main surfaces, the disk-shaped glass base plate being held by a carrier
  • the main surface of the glass base plate is sandwiched between polish
  • Yet another aspect of the present invention is a method of manufacturing a glass substrate for a magnetic disk comprising a pair of main surfaces and a side wall surface orthogonal to the pair of main surfaces, wherein the disk-shaped glass base plate is used as a carrier.
  • the first polishing step of polishing the main surface of the glass base plate the glass base plate is held by the carrier, the main surface of the glass base plate is sandwiched between the polishing pads, A polishing liquid having abrasive grains other than zirconia particles as abrasive grains is supplied between the glass base plate and the polishing pad, and between the side wall surface of the glass base plate and the end face of the carrier.
  • Relative base plate By causing moved includes a second polishing step of polishing the main surface of the glass work
  • the maximum gap between the glass base plate and the carrier is preferably 0.5 mm or more.
  • the surface roughness of the end surface of the carrier that contacts the side wall surface of the glass base plate is preferably 5 ⁇ m or less.
  • the surface roughness of the side wall surface of the glass base plate before being polished using the polishing liquid having zirconia particles is 0.1 ⁇ m or less in terms of arithmetic average roughness Ra. It is preferable.
  • the method for producing a glass substrate for a magnetic disk is preferably performed when the glass substrate for a magnetic disk has a diameter larger than 2.5 inches and a plate thickness of 0.6 mm or less.
  • the side wall surface of the glass base plate when the side wall surface of the glass base plate is polished, it may be polished using free abrasive grains.
  • the size of the free abrasive grains is zirconia. It is preferable that it is smaller than the grain size.
  • the method for manufacturing a glass substrate for a magnetic disk it is preferable to chemically strengthen the glass base plate after polishing the side wall surface of the glass base plate.
  • Aluminosilicate glass, soda lime glass, borosilicate glass, or the like can be used as the material for the magnetic disk glass substrate in the present embodiment.
  • aluminosilicate glass can be suitably used in that it can be chemically strengthened and a glass substrate for a magnetic disk excellent in the flatness of the main surface and the strength of the substrate can be produced.
  • the composition of the glass substrate for a magnetic disk of this embodiment is not limited, the glass substrate of this embodiment is preferably converted to an oxide standard and expressed in mol%, SiO 2 is 50 to 75%, Al 2 to O 3 to 1 to 15%, at least one component selected from Li 2 O, Na 2 O and K 2 O in total 5 to 35%, selected from MgO, CaO, SrO, BaO and ZnO 0-20% in total of at least one component, and at least one selected from ZrO 2 , TiO 2 , La 2 O 3 , Y 2 O 3 , Ta 2 O 5 , Nb 2 O 5 and HfO 2 An aluminosilicate glass having a composition having a total of 0 to 10% of the components.
  • the glass substrate for magnetic disk in this embodiment is an annular thin glass substrate.
  • the size of the glass substrate for magnetic disks is not ask
  • the flatness of the surface of the glass base plate obtained by the float process is sufficiently high.
  • a glass gob made of molten glass is supplied onto a lower mold that is a receiving gob forming mold, and an upper mold that is a lower mold and an opposing gob forming mold is used. Glass gob is press molded. More specifically, after a glass gob made of molten glass is supplied onto the lower mold, the lower surface of the upper mold cylinder and the upper surface of the lower mold cylinder are brought into contact with each other, and the upper mold and the upper mold mold are slid.
  • a glass base plate used as the origin of the glass substrate for magnetic discs is shape
  • a glass base plate can be manufactured using not only the method mentioned above but well-known manufacturing methods, such as a downdraw method, a redraw method, and a fusion method.
  • lapping processing using alumina-based loose abrasive grains is performed on both main surfaces of the glass base plate cut into a predetermined shape, if necessary.
  • the lapping platen is pressed on both sides of the glass base plate from above and below, a grinding liquid (slurry) containing free abrasive grains is supplied onto the main surface of the glass base plate, and these are moved relatively.
  • a grinding liquid (slurry) containing free abrasive grains is supplied onto the main surface of the glass base plate, and these are moved relatively. Perform lapping.
  • a glass base plate is shape
  • a chamfering step for forming a chamfered portion at the ends (outer peripheral end and inner peripheral end) is performed.
  • the outer peripheral end and the inner peripheral end of the annular glass base plate are chamfered with, for example, a metal bond grindstone using diamond abrasive grains to form a chamfered portion.
  • the double-sided grinding apparatus has a pair of upper and lower surface plates (upper surface plate and lower surface plate), and an annular glass base plate is sandwiched between the upper surface plate and the lower surface plate. Then, by moving both the upper surface plate and the lower surface plate, or both of them, the main surface of the glass base plate is ground by relatively moving the glass base plate and each surface plate. be able to.
  • First polishing (main surface polishing) step (S20) Next, 1st grinding
  • the machining allowance by the first polishing is, for example, about several ⁇ m to 50 ⁇ m.
  • the purpose of the first polishing is to remove scratches, distortion, waviness, and fine waviness remaining on the main surface by grinding with fixed abrasive grains.
  • the surface roughness (Ra) of the side wall surface of the glass base plate before the first polishing is preferably 0.1 ⁇ m or less, and more preferably 0.05 ⁇ m or less.
  • the surface roughness (Ra) here can be measured with a stylus roughness meter.
  • the contact area with the carrier can be increased, so that the number of abrasive grains intercalated increases and the force is distributed to more abrasive grains. Therefore, the ZrO 2 particles are less likely to pierce. Also, if the roughness is small, scratches caused by the carrier are less likely to enter when coming into contact with the carrier, so the probability of piercing the side wall surface of the glass base plate is indirectly reduced by reducing the number of ZrO 2 abrasive grains captured by the scratch. It can be made even smaller. Therefore, it is difficult for zirconia abrasive grains to stick to the side wall surface of the glass base plate during the first polishing.
  • FIG. 2 is an exploded perspective view of a polishing apparatus (double-side polishing apparatus) used in the first polishing step.
  • FIG. 3 is a cross-sectional view of a polishing apparatus (double-side polishing apparatus) used in the first polishing process. Note that the same configuration as this polishing apparatus can be applied to a grinding apparatus used in the above-described grinding process.
  • the polishing apparatus has a pair of upper and lower surface plates, that is, an upper surface plate 40 and a lower surface plate 50.
  • An annular glass base plate G is sandwiched between the upper surface plate 40 and the lower surface plate 50, and either one or both of the upper surface plate 40 and the lower surface plate 50 are moved to operate the glass base plate G. By moving the surface plates relative to each other, both main surfaces of the glass base plate G can be polished.
  • an annular flat polishing pad 10 is attached to the upper surface of the lower platen 50 and the bottom surface of the upper platen 40 as a whole.
  • the carrier 30 (holding member) includes a tooth portion 31 provided on the outer peripheral portion and meshing with the sun gear 61 and the internal gear 62, and one or a plurality of hole portions 31 for receiving and holding the glass base plate G. .
  • the surface roughness of the end surface of the hole 31 that contacts the side wall surface of the glass base plate (the wall surface facing the side wall surface of the glass base plate) is 5 ⁇ m or less, preferably 3 ⁇ m or less.
  • the surface roughness (Ra) here can be measured by moving the needle in the circumferential direction with respect to the end face of the hole 31 using a stylus type roughness meter. Since the surface roughness of the end face of the hole portion 31 of the carrier is so small, the contact area with the glass base plate can be increased, so that the number of abrasive grains entering between them increases, and more abrasive grains are obtained. Since the force is dispersed, the ZrO 2 particles are hardly stuck. In addition, if the roughness is small, scratches are less likely to enter the glass base plate when it comes into contact with the glass base plate, so that the ZrO 2 abrasive grains captured by the scratches are reduced, and the glass base plate is pierced.
  • the sun gear 61, the internal gear 62 provided on the outer edge, and the disk-shaped carrier 30 constitute a planetary gear mechanism centered on the central axis CTR as a whole.
  • the disc-shaped carrier 30 meshes with the sun gear 61 on the inner peripheral side and meshes with the internal gear 62 on the outer peripheral side, and accommodates and holds one or more glass base plates G (workpieces).
  • the carrier 30 revolves while rotating as a planetary gear, and the glass base plate G and the lower surface plate 50 are relatively moved.
  • the carrier 30 rotates in the CW (clockwise) direction
  • the internal gear 62 rotates in the CCW direction.
  • relative movement occurs between the polishing pad 10 and the glass base plate G.
  • the glass base plate G and the upper surface plate 40 may be relatively moved.
  • the upper surface plate 40 is pressed against the glass base plate G (that is, in the vertical direction) with a predetermined load, and the polishing pad 10 is pressed against the glass base plate G.
  • a polishing liquid (slurry) is supplied between the glass base plate G and the polishing pad 10 from the polishing liquid supply tank 71 via one or a plurality of pipes 72 by a pump (not shown).
  • the main surface of the glass base plate G is polished by the abrasive contained in the polishing liquid.
  • the polishing liquid used for polishing the glass base plate G is discharged from the upper and lower surface plates, returned to the polishing liquid supply tank 71 by a filter and a return pipe (not shown), and reused.
  • the load of the upper surface plate 40 applied to the glass base plate G is adjusted for the purpose of setting a desired polishing load on the glass base plate G.
  • the load is preferably 50 g / cm 2 or more, more preferably 70 g / cm 2 or more, and still more preferably 90 g / cm 2 or more from the viewpoint of achieving a high polishing rate and suppressing scratches on the glass base plate.
  • the polishing load is preferably 180 g / cm 2 or less, more preferably 160 g / cm 2 or less, and even more preferably 140 g / cm 2 or less.
  • the load is preferably 50 g / cm 2 to 180 g / cm 2, more preferably 70 g / cm 2 to 160 g / cm 2, and still more preferably 90 g / cm 2 to 140 g / cm 2 .
  • the load of the upper surface plate 40 applied to the glass base plate G may be adjusted for the purpose of achieving a processing rate equal to or higher than that in the case of polishing using cerium oxide abrasive grains. .
  • Load, 120 g / cm 2 or more is preferred from the viewpoint of high polishing rate achieved, more preferably from 130 g / cm 2 or more, more preferably 150 g / cm 2 or more.
  • the platen rotational speed is preferably 35 rpm or more, more preferably 50 rpm or more. Moreover, 1 rpm or more is preferable and, as for the rotational speed of the sun gear 61, 2 rpm or more is more preferable.
  • the supply rate of the polishing liquid during polishing varies depending on the polishing pad 10, the composition and concentration of the polishing liquid, and the size of the glass base plate G. From the viewpoint of suppressing scratches on the glass base plate while improving the polishing rate, 500 It is preferably ⁇ 5000 ml / min, more preferably 1000 to 4500 ml / min, and further preferably 1500 to 4000 ml / min.
  • the polishing liquid used in the polishing apparatus of FIG. 1 contains zirconia (ZrO 2 ) abrasive grains as an abrasive.
  • the average particle diameter (D50) of the zirconia abrasive is preferably 0.10 to 0.60 ⁇ m, more preferably 0.2 to 0.4 ⁇ m from the viewpoint of improving the polishing rate.
  • the average particle size (D50) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
  • the grain diameters of the abrasive grains uniform, and the standard deviation (SD) of the zirconia abrasive grains in the polishing liquid is 1 ⁇ m or less.
  • SD standard deviation
  • the zirconia abrasive grains in the polishing liquid is 1 ⁇ m or less.
  • it is 0.5 ⁇ m or less, more preferably 0.2 ⁇ m or less.
  • the surface irregularities of the main surface of the glass base plate are polished so that the roughness (Ra) is 0.5 nm or less and the micro waveness (MW-Rq) is 0.5 nm or less.
  • the micro waveness can be expressed by an RMS (Rq) value calculated as a roughness of a wavelength band of 100 to 500 ⁇ m in an area having a radius of 14.0 to 31.5 mm on the entire main surface. Measurement can be performed using Model-4224.
  • the roughness of the main surface is represented by the arithmetic average roughness Ra defined by JIS B0601: 2001.
  • the roughness is 0.006 ⁇ m or more and 200 ⁇ m or less, for example, the roughness is measured with a Mitutoyo Corporation roughness measuring machine SV-3100, It can be calculated by a method defined in JIS B0633: 2001.
  • the roughness is 0.03 ⁇ m or less, for example, it is measured with a scanning probe microscope (atomic force microscope; AFM) nanoscope manufactured by Japan Veeco, and calculated by the method defined in JIS R1683: 2007.
  • the arithmetic average roughness Ra when measured at a resolution of 512 ⁇ 512 pixels in a 1 ⁇ m ⁇ 1 ⁇ m square measurement area can be used.
  • End face polishing step (S22) Next, end face polishing (edge polishing) of the annular glass base plate is performed.
  • the end surface polishing is performed on the inner peripheral side wall surface (end surface) and the outer peripheral side wall surface (end surface) of the glass base plate.
  • end surface polishing removal of contamination such as dust on the side wall surface of the glass base plate, damage or scratches, etc., preventing the occurrence of thermal asperity, corrosion of sodium and potassium, etc. It is possible to prevent the occurrence of ion precipitation that is a cause.
  • end face polishing it is possible to physically remove zirconia particles that can adhere to the side wall surface of the glass base plate G in the first polishing step described above (removal step).
  • cleaning, etc. is not included in removing the zirconia particle physically mentioned in this specification.
  • the machining allowance of the side wall surface of the glass base plate by end face polishing is 30 ⁇ m or more, preferably 50 ⁇ m or more. Thereby, the zirconia particle adhering to the side wall surface of a glass base plate can be removed reliably.
  • polishing using fixed abrasive grains or polishing using free abrasive grains may be used, but fixed abrasive grains are preferred. .
  • the spacers are considered in consideration of a shift at the time of stacking individual glass substrates in a direction parallel to the main surface of the glass base plate. Is dimensioned so as to be located on the inner side (center side of the glass base plate) than the side wall surface of the glass base plate.
  • the outer peripheral edge portion of the main surface of each glass base plate is slightly but exposed.
  • the free abrasive grains may enter the outer peripheral edge portion of the exposed main surface of the glass base plate to roughen (damage) the surface. Therefore, in end face polishing, polishing using fixed abrasive grains that do not roughen the outer peripheral edge portion of the main surface with abrasive grains is preferable to polishing using loose abrasive grains.
  • a hard urethane pad JIS-A hardness: 60 to 95
  • abrasives other than zirconia such as cerium
  • the fixed abrasive grains preferable. Since it is the side wall surface of the glass base plate that the zirconia particles adhere in the first polishing step of the previous step, when polishing the laminated body of the glass base plate, depending on the side wall surface of each glass base plate What is necessary is just to grind
  • end face polishing is performed using loose abrasive grains
  • a slurry (polishing liquid) containing fine particles such as cerium oxide as loose abrasive grains may be used.
  • the size of the loose abrasive used in the end face polishing is smaller than the size of the zirconia abrasive used in the first polishing. This is because even when free abrasive grains enter the main surface of the glass base plate during end surface polishing, since the free abrasive grains are smaller than the zirconia particles, the surface properties obtained in the first polishing step are This is because it does not worsen.
  • the average value (D50) of the free abrasive grains is 0.3 to 1.0 ⁇ m.
  • Chemical strengthening step (S24) the glass base plate after the first polishing is chemically strengthened.
  • the chemical strengthening solution for example, a mixed solution of potassium nitrate (60% by weight) and sodium sulfate (40% by weight) can be used.
  • the chemical strengthening liquid is heated to, for example, 300 ° C. to 400 ° C., and after the cleaned glass base plate is preheated to, for example, 200 ° C. to 300 ° C., the glass base plate is placed in the chemical strengthening liquid, for example, 1 Soak for 5 to 5 hours.
  • the immersion is preferably performed in a state of being housed in a holder so that the plurality of glass base plates are held by the side wall surfaces so that the entire main surfaces of both glass base plates are chemically strengthened.
  • the glass base plate is strengthened.
  • the chemically strengthened glass base plate is washed. For example, after washing with sulfuric acid, it is washed with pure water or the like.
  • Second polishing (final polishing) step (S26) final polishing is performed on the chemically strengthened and sufficiently cleaned glass base plate.
  • the machining allowance by the final polishing is 5 ⁇ m or less.
  • the second polishing is intended for mirror polishing of the main surface.
  • the polishing apparatus used in the first polishing is used.
  • the difference from the first polishing is that the type and particle size of the free abrasive grains are different and the hardness of the resin polisher is different.
  • the free abrasive grains used in the second polishing for example, fine particles (particle size: diameter of about 10 to 50 nm) such as colloidal silica made turbid in the slurry are used.
  • a glass substrate for a magnetic disk can be obtained by washing the polished glass base plate with a neutral detergent, pure water, IPA or the like.
  • the end face polishing step may be performed after the first polishing step using zirconia abrasive grains, and the other order may be changed as appropriate.
  • the chemical strengthening step may be performed before the first polishing step.
  • the glass in the end face polishing step after the first polishing step of polishing the main surface of the glass base plate using a polishing liquid containing zirconia as polishing abrasive grains, the glass in the end face polishing step.
  • the zirconia particles attached to the side wall surface of the glass base plate in the first polishing step are removed in the subsequent end surface polishing step.
  • polishing can be performed at a high processing rate even under relatively gentle processing conditions.
  • polishing could be performed under processing conditions where the processing pressure was about 100 g / cm 2 and the rotation speed of the surface plate was about 10 rpm.
  • the processing rate becomes extremely worse if the same processing conditions as when using cerium oxide abrasive grains are applied, so that processing is severer than when cerium oxide is used. Conditions need to be applied.
  • zirconia abrasive grains are different from the general processing conditions in the case of using cerium oxide, zirconia abrasive grains are formed on the side wall surface of the glass base plate during main surface polishing. There is a problem that it sticks easily by sticking.
  • the zirconia particles attached to the side wall surface of the glass base plate in the first polishing step are removed in the subsequent end surface polishing step, the zirconia particles are removed from the glass base plate in the subsequent step. It will not adhere to the main surface.
  • the manufacturing method of this embodiment is suitable for manufacturing a glass substrate for a magnetic disk having a diameter larger than 2.5 inch size and a plate thickness of 0.6 mm or less.
  • a glass substrate for a magnetic disk has a higher aspect ratio (diameter / plate thickness) than the conventional one. For this reason, since the plate
  • the zirconia particles are likely to adhere to the side wall surface of the glass base plate, and the ratio of the zirconia particles attached to the side wall surface of the glass base plate increases.
  • the zirconia particle adhering to the side wall surface of a glass base plate is removed in an end surface grinding
  • a magnetic disk is obtained as follows using a magnetic disk glass substrate.
  • the magnetic disk is, for example, on the main surface of a glass substrate for magnetic disk (hereinafter simply referred to as “substrate”), in order from the closest to the main surface, at least an adhesion layer, an underlayer, a magnetic layer (magnetic recording layer), and a protective layer.
  • a layer and a lubricating layer are laminated.
  • the substrate is introduced into a film forming apparatus that has been evacuated, and a film is sequentially formed from an adhesion layer to a magnetic layer on the main surface of the substrate in an Ar atmosphere by a DC magnetron sputtering method.
  • a magnetic recording medium can be formed by forming a protective layer using, for example, C 2 H 4 by a CVD method and subsequently performing nitriding treatment for introducing nitrogen into the surface. Thereafter, for example, PFPE (perfluoropolyether) is applied on the protective layer by a dip coating method, whereby a lubricating layer can be formed.
  • the produced magnetic disk is preferably incorporated in an HDD (Hard Disk Drive) as a magnetic recording / reproducing apparatus together with a magnetic head equipped with a DFH (Dynamic Flying Height) control mechanism.
  • HDD Hard Disk Drive
  • DFH Dynamic Flying Height
  • the manufacturing method of the glass substrate of 2nd Embodiment is a glass base plate shaping
  • Each step includes a grinding step with grains (S40), a first polishing (main surface polishing) step (S42), a second polishing step (S44), a chemical strengthening step (S46), and a final polishing step (S48).
  • End face polishing step (S38) Except for the following points, it is performed in the same manner as the end surface polishing step (S22) of the first embodiment.
  • the inner peripheral side wall surface (end surface) and the outer peripheral side wall surface (end surface) of the glass base plate are mirror-finished by brush polishing.
  • a slurry containing fine particles such as cerium oxide as free abrasive grains is used.
  • the end surface polishing step is performed before the first polishing step in order to smooth the end surface of the glass base plate and thereby make it difficult for the zirconia abrasive grains to adhere to the side wall surface of the glass base plate in the first polishing step of the subsequent step. It is preferable.
  • the end surface polishing so that the arithmetic average roughness Ra of the end surface of the glass base plate after the end surface polishing step is 0.1 ⁇ m or less.
  • polishing in order to remove the zirconia particles adhering to the side wall surface of the glass base plate G by polishing, either polishing using fixed abrasive grains or polishing using free abrasive grains may be used.
  • Second polishing step (S44) In the second polishing step (S44), second polishing is performed on the main surface of the glass base plate that has undergone the first polishing step.
  • the machining allowance by the second polishing is, for example, about several ⁇ m to 20 ⁇ m, preferably 30 ⁇ m or more, more preferably 50 ⁇ m or more.
  • the zirconia particle adhering to the side wall surface of a glass base plate can be removed reliably.
  • the main surface is polished at a high polishing rate, and zirconia particles that can adhere to the side wall surface of the glass base plate in the first polishing step are physically removed (removal step is performed).
  • FIG. 5 is a view showing a state in which the glass base plate G is accommodated in the hole 31 of the carrier 30. As shown in FIG. 5, when the outer diameter of the glass base plate G to be polished is D1, and the diameter of the hole 31 of the carrier 30 (the diameter of the contact surface with which the glass base plate abuts) is D2, D2> D1 Is established.
  • the gap CL is provided to such an extent that it can be).
  • the maximum value of the gap CL (maximum gap) is (D2-D1) at the maximum.
  • the maximum value of the relative displacement amount between the glass base plate G and the carrier 30 is defined by the gap CL.
  • the main surface is polished on the main surface of the glass base plate G in a state where cerium oxide abrasive grains are supplied to the gap CL between the glass base plate G and the hole 31 of the carrier 30. If it carries out, it will become possible to remove the zirconia particles adhering to the side wall surface Gt of the glass base plate G in the first polishing. This is due to the action described below. That is, during the polishing process, the glass base plate G moves in an unconstrained state in the hole 31 of the carrier 30 in a direction parallel to the main surface while being loaded by the surface plate in the thickness direction.
  • the side wall surface Gt of the glass base plate G is brought into contact with the side wall surface 30 t forming the hole portion 31, but the cerium oxide abrasive supplied to the gap CL between the glass base plate G and the hole portion 31 of the carrier 30.
  • the grains polish the side wall surface Gt of the glass base plate G, whereby the zirconia particles adhering to the side wall surface Gt are detached from the side wall surface Gt of the glass base plate G.
  • the zirconia particles separated from the side wall surface Gt are discharged together with the polishing liquid.
  • the surface property of the side wall surface Gt is not deteriorated (that is, the surface is roughened) by an impact when the side wall surface Gt of the glass base plate G abuts on the side wall surface 30t of the carrier 30.
  • An elastic member may be provided on the side wall surface 30t.
  • a sufficient amount of abrasive grains of cerium oxide (CeO 2 ) is supplied between the side wall surface Gt of the glass base plate G and the side wall surface 30t forming the hole 31 of the carrier 30 to the side wall surface Gt of the glass base plate G.
  • the maximum value (maximum gap; D2-D1) of the gap CL between the side wall surface Gt of the glass base plate G and the side wall surface 30t of the carrier 30 is preferably 0.5 mm or more. More preferably, it is 1.0 mm or more.
  • the concentration of the cerium oxide abrasive in the polishing liquid is 5 to 30% by weight from the viewpoint of efficiently polishing the side wall surface Gt of the glass base plate G with the cerium oxide abrasive to remove the zirconia particles. It is preferable.
  • the abrasive supplied to the gap CL between the glass base plate G and the hole 31 of the carrier 30 is not limited to cerium oxide abrasive grains, but may be other abrasives. That is, cerium oxide abrasive grains are preferable from the viewpoint of increasing the processing rate of the main surface polishing, but the second purpose of the second polishing is to physically remove zirconia particles that can adhere to the side wall surface of the glass base plate. In some cases, the abrasive may not be cerium oxide abrasive. As other abrasives, for example, abrasive grains of alumina, diamond, titanium, and silica may be used.
  • the average particle diameter (D50) of the abrasive grains in the polishing liquid in the second polishing is preferably equal to or smaller than the average particle diameter (D50) of the zirconia abrasive grains in the first polishing.
  • the roughness (Ra) of the surface irregularities on the main surface of the glass base plate is 0.5 nm or less.
  • polishing is performed so that the micro waveness (MW-Rq) is 0.5 nm or less.
  • Chemical strengthening step (S46) It is performed in the same manner as the chemical strengthening step (S24) of the first embodiment.
  • Final polishing step (S48) This is performed in substantially the same manner as the second polishing (final polishing) step (S26) of the first embodiment.
  • the maximum value (maximum gap) of the gap between the side wall surface of the glass base plate and the side wall surface of the carrier is 0.5 mm or more. Preferably, it is 1.0 mm or more.
  • particles such as colloidal silica are supplied between the glass base plate and the hole of the carrier in the same manner as shown in FIG.
  • the zirconia particles adhering to the side wall surface may be removed by polishing.
  • the glass substrate for magnetic disk and the magnetic disk are the same as described in the first embodiment.
  • Examples and comparative examples related to the first embodiment In order to confirm the effect of the manufacturing method of the glass substrate of the first embodiment, a 2.5-inch magnetic disk is manufactured from the manufactured glass substrate, a LUL durability test is performed, and a head crash failure, a thermal asperity failure, etc. The presence or absence of defects was examined.
  • the composition of the glass of the manufactured magnetic disk glass substrate is as follows (% means mass%).
  • Glass composition Converted to oxide basis, expressed in mol%, SiO 2 is 50 to 75%, Al 2 O 3 is 1 to 15%, at least one component selected from Li 2 O, Na 2 O and K 2 O 5 to 35% in total, 0 to 20% in total of at least one component selected from MgO, CaO, SrO, BaO and ZnO, and ZrO 2 , TiO 2 , La 2 O 3 , Y 2 O 3 , Aluminosilicate glass having a composition having a total of 0 to 10% of at least one component selected from Ta 2 O 5 , Nb 2 O 5 and HfO 2
  • the glass base plate of (1) was formed by using a press molding method used in the method for manufacturing a magnetic disk glass substrate described in JP2011-138589A. .
  • lapping alumina-based free abrasive grains having an average particle diameter of 20 ⁇ m were used.
  • the diamond sheet (average particle diameter: 1 to 20 ⁇ m) was ground by using a grinding apparatus in which a diamond sheet obtained by hardening a resin bond was attached to the upper and lower surface plates.
  • the glass base plate was immersed in the chemical strengthening solution for 4 hours.
  • polishing was performed for a predetermined time using colloidal silica having a particle diameter of 10 to 50 ⁇ m using a polishing apparatus similar to the polishing apparatus of FIGS. Thereby, arithmetic mean roughness Ra (JIS B0601: 2001) of the main surface was made into 0.15 nm or less.
  • the glass base plate after the second polishing was cleaned using a neutral cleaning solution and an alkaline cleaning solution. This obtained the glass substrate for magnetic discs.
  • the average particle size (D50) was measured by a light scattering method using a particle size / particle size distribution measuring apparatus (Nikkiso Co., Ltd., Nanotrac UPA-EX150).
  • a magnetic disk having a magnetic layer formed on the obtained glass substrate for a magnetic disk was prepared, and evaluated by performing a LUL durability test (600,000 times).
  • the LUL endurance test is a state in which a hard disk drive (HDD) constituting a magnetic disk is placed in a constant temperature and humidity layer at a temperature of 70 ° C. and a humidity of 80% without stopping the movement of the head between the lamp and the ID stopper. It is a test to investigate the occurrence of abnormalities such as dirt and wear of the head after the test by reciprocating motion (seek operation).
  • Step, (5) first polishing (main surface polishing) step, (6) end surface polishing step, (7) chemical strengthening step, and (8) second polishing (final) polishing step are performed in this order. It was. That is, the end face polishing step was performed after the first polishing step.
  • each process of the manufacturing method of the glass substrate of 2nd Embodiment was performed in order.
  • a plurality of glass base plates laminated with a spacer interposed between the glass base plates is polished using cerium oxide having an average particle size (D50) of 1.0 ⁇ m as free abrasive grains. Polished with a brush.
  • the diamond sheet (average particle diameter: 1 to 20 ⁇ m) was ground by using a grinding apparatus in which a diamond sheet obtained by hardening a resin bond was attached to the upper surface plate and the lower surface plate.
  • polishing was performed for 60 minutes using the polishing apparatus of FIGS.
  • polishing conditions are as shown below.
  • polishing was performed for 30 minutes using another polishing apparatus similar to that shown in FIGS.
  • Detailed polishing conditions are as shown below.
  • the maximum gap between the glass base plate and the carrier of the polishing apparatus is as shown in Table 2.
  • Polishing pad Hard urethane pad (JIS-A hardness: 80-100) Polishing load: 120 g / cm 2 ⁇ Surface plate speed: 30 rpm Polishing fluid supply flow rate: 3000 L / min Polishing liquid: 15% by weight of zirconia (ZrO2) is contained as abrasive grains.
  • Polishing pad Hard urethane pad (JIS-A hardness: 80-100) Polishing load: 120 g / cm 2 ⁇ Surface plate speed: 30 rpm Polishing fluid supply flow rate: 3000 L / min Polishing liquid: 15% by weight of abrasive grains described in Tables 1 and 2 are contained.
  • a magnetic disk having a magnetic layer formed on the obtained glass substrate for a magnetic disk was produced, and evaluated by performing an LUL durability test (two types of 400,000 times and 600,000 times).
  • the LUL endurance test is a state in which a hard disk drive (HDD) constituting a magnetic disk is placed in a constant temperature and humidity layer at a temperature of 70 ° C. and a humidity of 80% without stopping the movement of the head between the lamp and the ID stopper. It is a test to investigate the occurrence of abnormalities such as dirt and wear of the head after the test by reciprocating motion (seek operation).
  • the maximum gap is provided at least 0.5 [mm] or more, the abrasive grains are supplied to the gap between the glass base plate and the carrier, and the side wall surface of the glass base plate It can be seen that the zirconia particles adhered to the side wall surface could be removed. Furthermore, if the maximum gap is set to 1.0 [mm] or more, the abrasive grains are sufficiently supplied to the gap between the carrier and the glass base plate, and the removal performance of zirconia particles can be sufficiently ensured.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
  • Surface Treatment Of Glass (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'un substrat en verre de disque magnétique. Selon l'invention, le procédé comprend le polissage effectué par utilisation de grains abrasifs de zircone comme matériau de polissage à grains abrasifs dispersés et permet la fabrication d'un substrat en verre de disque magnétique pour lequel il y a peu de risques d'apparition de dysfonctionnements comme une défaillance d'accrochage de la tête ou une défaillance liée à une aspérité thermique. Ce procédé, qui est un procédé de fabrication d'un substrat en verre de disque magnétique comprenant deux surfaces principales et une surface de paroi latérale perpendiculaire aux deux surfaces principales, comprend les étapes suivantes : une étape de polissage pendant laquelle l'ébauche de verre en forme de disque est maintenue dans un support, les surfaces principales de l'ébauche de verre sont prises en sandwich par des tampons de polissage, un liquide de polissage comprenant des particules de zircone comme grain abrasif de polissage est amené entre l'ébauche de verre et les tampons de polissage, et les surfaces principales de l'ébauche de verre sont polies par un déplacement relatif des tampons de polissage et de l'ébauche de verre ; et une étape de retrait dans laquelle, après l'étape de polissage, lorsque la surface de paroi latérale ou les surfaces principales de l'ébauche de verre ont été polies, la surface de paroi latérale de l'ébauche de verre et les surfaces d'extrémité du support orienté vers la surface de paroi latérale du substrat en verre frottent les unes contre les autres et, comme résultat, les particules de zircone qui ont adhéré à la surface de paroi latérale de l'ébauche de verre sont physiquement éliminées.
PCT/JP2012/084234 2011-12-29 2012-12-28 Procédé de fabrication d'un substrat en verre de disque magnétique WO2013100154A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017182858A (ja) * 2016-03-31 2017-10-05 株式会社フジミインコーポレーテッド 研磨用組成物、基板の研磨方法および基板の製造方法
EP3670081A4 (fr) * 2017-12-27 2021-07-14 Hoya Corporation Procédé de fabrication de substrat en verre en forme de disque, procédé de fabrication de substrat en verre en feuille, procédé de fabrication de plaque guide de lumière et substrat en verre en forme de disque

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SG10201912466TA (en) * 2015-03-31 2020-02-27 Hoya Corp Magnetic-disk substrate, magnetic disk, and method for manufacturing magnetic-disk substrate
CN109712648B (zh) * 2017-10-25 2022-02-22 新科实业有限公司 研磨用的坯体及其制造方法、金刚石研磨坯的制造方法
CN115816267A (zh) * 2022-12-29 2023-03-21 西安奕斯伟材料科技有限公司 硅片双面抛光装置的承载件及硅片双面抛光装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10121034A (ja) * 1996-03-18 1998-05-12 Showa Denko Kk 磁気ディスク基板の研磨用組成物
JP2001162510A (ja) * 1999-09-30 2001-06-19 Hoya Corp 研磨方法並びに磁気記録媒体用ガラス基板の製造方法及び磁気記録媒体の製造方法
JP2006053965A (ja) * 2004-08-10 2006-02-23 Fuji Electric Device Technology Co Ltd 磁気記録媒体用基板の製造方法並びにそれに用いる両面研磨装置及び基板研磨用キャリア
JP2008176843A (ja) * 2007-01-17 2008-07-31 Konica Minolta Opto Inc 磁気記録媒体用基板、及び磁気記録媒体用基板の製造方法
JP2009173538A (ja) * 2001-09-26 2009-08-06 Hitachi Maxell Ltd 非磁性板状粒子とその製造方法
JP2011207626A (ja) * 2009-06-04 2011-10-20 Ohara Inc 情報記録媒体用結晶化ガラス基板およびその製造方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2003292786A1 (en) * 2002-12-26 2004-07-22 Hoya Corporation Method for producing glass substrate for information recording medium, polishing apparatus and glass substrate for information recording medium
JP2008226349A (ja) * 2007-03-13 2008-09-25 Showa Denko Kk 円盤状基板の製造方法、洗浄装置
CN101796582A (zh) * 2007-09-04 2010-08-04 柯尼卡美能达精密光学株式会社 信息记录介质用玻璃基板的制造方法、信息记录介质用玻璃基板以及磁记录介质

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10121034A (ja) * 1996-03-18 1998-05-12 Showa Denko Kk 磁気ディスク基板の研磨用組成物
JP2001162510A (ja) * 1999-09-30 2001-06-19 Hoya Corp 研磨方法並びに磁気記録媒体用ガラス基板の製造方法及び磁気記録媒体の製造方法
JP2009173538A (ja) * 2001-09-26 2009-08-06 Hitachi Maxell Ltd 非磁性板状粒子とその製造方法
JP2006053965A (ja) * 2004-08-10 2006-02-23 Fuji Electric Device Technology Co Ltd 磁気記録媒体用基板の製造方法並びにそれに用いる両面研磨装置及び基板研磨用キャリア
JP2008176843A (ja) * 2007-01-17 2008-07-31 Konica Minolta Opto Inc 磁気記録媒体用基板、及び磁気記録媒体用基板の製造方法
JP2011207626A (ja) * 2009-06-04 2011-10-20 Ohara Inc 情報記録媒体用結晶化ガラス基板およびその製造方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017182858A (ja) * 2016-03-31 2017-10-05 株式会社フジミインコーポレーテッド 研磨用組成物、基板の研磨方法および基板の製造方法
EP3670081A4 (fr) * 2017-12-27 2021-07-14 Hoya Corporation Procédé de fabrication de substrat en verre en forme de disque, procédé de fabrication de substrat en verre en feuille, procédé de fabrication de plaque guide de lumière et substrat en verre en forme de disque

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