JP2008059728A - Inner peripheral edge surface polishing device of glass substrate for magnetic disk, manufacturing method of glass substrate for magnetic disk, and manufacturing method of magnetic disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce operation time while tolerance and roundness of inner holes of glass substrates are enhanced in polishing an inner peripheral edge surface of the glass substrates for magnetic disks. <P>SOLUTION: A manufacturing method of the glass substrates for the magnetic disks having the inner holes at a center thereof includes a step for fixing a work holder 100 to a table 201 of an inner peripheral edge surface polishing device 1 so that a center axis of the plurality of glass substrates 10 laminated in the work holder 100 and a rotational axis of a polishing means 203 polishing the connected inner holes of the glass substrates 10 are aligned with each other and a step for rotating the table 201 and the polishing means 203 to polish the inner peripheral edge surfaces of the glass substrates 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to polishing of an inner peripheral end face of a magnetic disk glass substrate.

  In recent years, with the advancement of information technology, information recording technology, particularly magnetic recording technology, has made remarkable progress. An aluminum substrate has been widely used as a substrate for a magnetic recording medium such as an HDD (Hard Disk Drive) which is one of the magnetic recording media. However, with the miniaturization, thinning, and high-density recording of magnetic disks, glass substrates that are superior in substrate surface flatness and substrate strength compared to aluminum substrates are gradually being replaced.

  As the magnetic recording technology has been increased in density, the magnetic head has been changed from a thin film head to a magnetoresistive head (MR head) and a large magnetoresistive head (GMR head). The flying height from is narrowed to about 8 nm. For this reason, if there is an uneven shape on the magnetic disk surface, there may be a crash failure in which the magnetic head collides, or a thermal asperity failure that causes a read error due to adiabatic compression or contact of air. Under the circumstances as described above, the importance of the smoothness of the end face of the substrate has been recognized conventionally. In Patent Document 1 (Japanese Patent Laid-Open No. 10-154321), it is possible to prevent generation and adsorption of particles on the substrate end surface by polishing the outer periphery and inner peripheral end surface of the substrate until they reach the mirror surface, thereby solving the above problem. Yes.

As a configuration for polishing the inner peripheral end face of the glass substrate, a polishing method using a rotating brush as described in Patent Document 2 (Japanese Patent Laid-Open No. 11-221742) is known. In this conventional polishing method, a disk-shaped glass substrate 1 is laminated to form a columnar shape, and a rotating brush 50 is inserted into a communicating inner hole, and while supplying a polishing liquid (slurry), the glass substrate 1 and the rotating brush 50 The inner peripheral end face is polished by rotating each of these.
JP-A-10-154321 JP-A-11-221742

  Recently, in order to further improve the recording density, a perpendicular magnetic recording system is being adopted. In the case of this perpendicular magnetic recording medium, the influence of the glass substrate tends to appear more conspicuously than in the case of the in-plane magnetic recording system. For this reason, the glass substrate is required to have lower roughness, flatness, and shape accuracy. In particular, the rotational speed of the magnetic disk tends to increase in order to improve the read / write speed of the hard disk, and the center of gravity of the rotation of the magnetic disk is extremely important. For this reason, there is a demand for higher accuracy with respect to the small dimensional tolerance and the high roundness of the inner hole (inner peripheral end face), and thus the small fitting tolerance with the spindle.

  On the other hand, in recent years, there has been a demand for small hard disks to be mounted especially on mobile phones, digital cameras, portable music players, etc., and magnetic disks are required to be further downsized, higher in recording density, and lower in cost. It has been.

  Here, in order to reduce the production cost in polishing the inner peripheral end face of the glass substrate, it is conceivable to shorten the working time during polishing. However, in order to process with high accuracy, it is necessary to attach the workpiece (glass substrate) to the polishing apparatus with high accuracy, and work time corresponding to that is required. Further, as in the case of shortening the work time, it is also conceivable to increase the number of stacked layers during polishing. For example, if 300 sheets are stacked and polished up to now, if 300 sheets are stacked and polished, production can be simply performed with 1/3 tact (processing time). However, as the number of stacked layers is increased, tolerance and roundness tend to decrease.

  Accordingly, the present invention provides a glass disk substrate inner surface polishing apparatus and a magnetic disk glass substrate capable of reducing working time while improving tolerance and roundness of the inner hole of the glass substrate. It is an object to provide a method and a method of manufacturing a magnetic disk.

  The inventors of the present invention have made extensive studies on the above problems, and as a result, when the work holder holding the glass substrate is decentered or tilted with respect to the table when polishing the inner circumference, the tolerance of the inner hole and I found out that the roundness would decrease. In particular, when it is inclined, the tolerance and the like are significantly reduced when the number of stacked layers is increased. Then, as a result of examining the polishing process to solve this problem, in the stage of fixing the work holder to the inner peripheral end surface polishing apparatus, a fixing means for matching the central axis of the work holder with the central axis of the polishing means is used. Thus, it has been found that the degree of coincidence can be improved and the working time can be shortened, and the present invention has been completed.

  That is, in order to solve the above problems, a typical configuration of a method for manufacturing a glass substrate for a magnetic disk according to the present invention is laminated on a work holder in the method for manufacturing a glass substrate for a magnetic disk having an inner hole at the center. A step of fixing a work holder to a table of an inner peripheral end surface polishing apparatus so that a central axis of a plurality of glass substrates and a rotation axis of a polishing means for polishing an inner hole communicating with the glass substrates are aligned; And rotating the means to polish the inner peripheral end face of the glass substrate.

  According to the said structure, the center axis | shaft of a glass substrate and the rotating shaft of a grinding | polishing means can be corresponded only by fixing a work holder to the table | surface of a grinding | polishing apparatus. Therefore, the working time can be shortened while improving the tolerance and roundness of the inner hole of the glass substrate.

  The step of fixing the work holder to the table of the inner peripheral end surface polishing apparatus includes the step of placing the work holder on the table of the inner peripheral end surface polishing apparatus, and the central axis of the glass substrate laminated by the fixing means provided on the table. And a step of fixing the work holder in a direction orthogonal to each other.

  A typical configuration of an inner peripheral end surface polishing apparatus for a magnetic disk glass substrate according to the present invention is a state in which a plurality of glass substrates are laminated in an inner peripheral end surface polishing apparatus for a magnetic disk glass substrate having an inner hole in the center. A table for supporting the work holder held in step 1, a polishing means for polishing the inner peripheral end surface of the glass substrate by being inserted into an inner hole communicating with the glass substrate and rotating, and a slurry supply means for supplying slurry to the polishing portion The table further includes fixing means for positioning and fixing the work holder in a direction orthogonal to the central axis of the laminated glass substrates, and the fixing means includes the work holder and the central axis of the laminated glass substrates. It is characterized by fixing so that the rotating shaft of a grinding | polishing means may correspond.

  The fixing means may be configured to position and fix the protrusion protruding below the work holder in a direction perpendicular to the central axis of the laminated glass substrates. Alternatively, the central axis of the laminated glass substrate and the rotation axis of the polishing means may be aligned and fixed by pressing the protrusion of the work holder from the entire circumferential direction. Or you may provide the positioning member which contact | abuts to the projection part of a work holder from at least 2 directions, and the urging means which urges the projection part of a work holder to a positioning member. Or you may provide the internal thread part fitted with the external thread part formed in the outer peripheral surface of the protrusion part of a work holder. It is an example of the concrete structure of a fixing means.

  Another typical configuration of the inner peripheral end surface polishing apparatus for a magnetic disk glass substrate according to the present invention is a method of laminating a plurality of glass substrates in an inner peripheral end surface polishing apparatus for a magnetic disk glass substrate having an inner hole in the center. A table for supporting the work holder held in a state in which it is held, a polishing means for polishing the inner peripheral end surface of the glass substrate by being inserted into an inner hole communicating with the glass substrate and rotating, and a slurry for supplying slurry to the polishing site And the table further includes a fixing means for positioning and fixing the work holder, and the fixing means presses a projecting portion projecting downward from the work holder from the entire circumferential direction, thereby pressing the work holder. The center axis of the laminated glass substrate is fixed so that the rotation axis of the polishing means coincides.

  A typical configuration of a magnetic disk according to the present invention is characterized in that at least a magnetic layer is formed on the surface of a glass substrate obtained by the method for manufacturing a glass substrate for a magnetic disk.

  According to the present invention, while improving the tolerance and roundness of the inner hole of the glass substrate, the working time can be shortened, and the production cost can be reduced by increasing the number of laminated layers at the time of inner circumference polishing. .

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an inner peripheral end surface polishing apparatus, a magnetic disk glass substrate manufacturing method, and a magnetic disk manufacturing method according to the present invention will be described. FIG. 1 is a diagram illustrating an inner peripheral end surface polishing apparatus, FIGS. 2 to 5 are diagrams illustrating a fixing unit, and FIG. 6 is a diagram illustrating a configuration of an inner peripheral end surface polishing apparatus for reference. Note that specific dimensions, shapes, materials, and other numerical values shown in the following embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. .

  A polishing apparatus 1 shown in FIG. 1 is an apparatus for polishing inner peripheral end surfaces of a plurality of glass substrates. The polishing apparatus 1 includes a table 201 that rotates while supporting the work holder 100, and a brush 203 as an example of a polishing unit that polishes the inner peripheral end surface of the glass substrate. The table 201 is configured to be rotatable with respect to the base 202. Further, as will be described later, the table 201 includes a fixing means 200 that positions and fixes the work holder 100 in a direction orthogonal to the central axis of the laminated glass substrates 10.

  The brush 203 is inserted through the inner hole of the glass substrate 10 held by the work holder 100. The brush shaft 204 of the brush 203 is rotationally driven by a drive shaft 205 at its upper end and is rotatably supported by a brush lower end support portion 206 at its lower end. The brush 203 is also swung in the vertical direction while being driven to rotate, thereby polishing the inner peripheral end surface of the glass substrate 10. At the time of polishing, a slurry mixed with abrasive grains is supplied to a polishing portion from a nozzle 207 as an example of a slurry supply unit. In the present embodiment, both the table 201 and the brush 203 are configured to rotate. However, only one of the table and the brush may be configured to rotate.

  The work holder 100 stacks and holds a magnetic disk glass substrate having an inner hole in the center. A plurality of glass substrates 10 (for example, 100 to 300) are laminated, and are sandwiched between the lower support portion 101 and the upper support portion 104 with the inner holes communicating. Below the lower support portion 101, a protruding portion 107 is formed to protrude. The protrusion 107 is a tubular body in the present embodiment, and the brush 203 or 206 can be disposed in the inner hole.

  The upper surface of the fixing means 200 is orthogonal to the rotation center of the table 201. The lower surface of the lower support portion 101 of the work holder 100 (portion other than the protruding portion 107) is orthogonal to the central axis of the work holder 100 (that is, the central axis of the laminated glass substrates). Therefore, by placing the work holder 100 on the fixing means 200, the center axis of the work holder 100 and the rotation center of the table 201 become parallel. Note that the rotation axis of the brush 203 is parallel to the rotation center of the table 201.

  FIG. 2 is a view showing a bush 210 as an example of the fixing means 200. In the bush 210, a step portion 211 a having a small diameter in the main body 211 is inserted into a hole 201 a of the table 201, and is fixed to the table 201 with a fastener such as a bolt 209. An inner hole 210 a is formed at the center of the bush 210, and the protrusion 107 of the lower support portion 101 of the work holder 100 is inserted therein.

  As shown in FIG. 3, the bush body 211 is provided with a screw hole 212, and a screw 213 is rotatably attached from the outside. A space 214 inside the screw 213 is filled with a fluid pressure medium (for example, oil), and the space 214 communicates with a gap 215 between the sleeve 216 and the main body 211 forming the inner hole 210a. The sleeve 216 has elasticity and is displaced by the pressure received from the gap 215. Therefore, by rotating the screw 213 and moving it, the sleeve 216 can be displaced via the pressure medium in the space 214 and the gap 215, and the diameter of the inner hole 210a can be changed.

  The work holder 100 is replaced for each work, but the bush 210 is fixedly provided on the polishing apparatus 1. The bush 210 is orthogonal to the rotation center of the table 201. The central axis of the inner hole 210 a of the bush is coaxial with the rotation center of the table 201.

  By using such a bush 210, the protrusion 107 can be pressed from the entire circumference only by rotating the screw 213, and can be positioned and fixed in a direction perpendicular to the central axis of the laminated glass substrates. At this time, even if the protrusion 107 is deviated from the rotation center of the table 201, the work holder 100 can be moved in parallel to correct the position by tightening with the same pressure from the entire circumferential direction. The center and the center axis of the work holder 100 (that is, the center axis of the laminated glass substrates 10) can be matched. That is, centering can be performed mechanically while fixing the work holder 100 without requiring position adjustment by an operator.

  FIG. 6 is a diagram showing a configuration of an inner peripheral end surface polishing apparatus for reference. In FIG. 6, the fixing means 200 is not provided, and the lower support portion 101 is directly fixed to the table 201 with a bolt 208 or the like. A protrusion 107 is provided at a lower portion of the lower support portion 101 and is fitted to a hole 201a of the table 201 with a predetermined fitting tolerance.

  In the configuration of FIG. 6, the worker first tightens the bolt 208 lightly, finely adjusts the position of the work holder 100 while rotating the table 201, confirms that the core is out, and then tightens the bolt 208. Tighten. This position adjustment takes about 5 minutes on average, and the work holder 100 is inclined depending on the tightening method. In addition, the accuracy depends largely on the skill of the workers.

  However, according to the configuration of the present embodiment, if the work holder 100 is fixed, the rotation axis of the work holder 100 and the rotation center of the table 201 inevitably coincide with each other. The production cost can be reduced. In addition, the work holder 100 is not inclined due to the tightening method, and even if the number of the glass substrates 10 stacked on the work holder 100 is increased, the glass substrate can be reliably prevented from being inclined. Therefore, the production cost can also be reduced by increasing the number of sheets that can be polished at one time while improving the tolerance and roundness of the inner hole of the glass substrate.

  In the configuration of FIG. 6, the fitting tolerance between the protrusion 107 and the table hole 201a is about 50 μm, which is sufficient for the processing accuracy of the inner hole (inner peripheral end face) required for the conventional glass substrate. It was. However, as explained in the above section, high accuracy is required for the small dimensional tolerance and roundness of the inner hole (inner peripheral end face) and the small fitting tolerance with the spindle. It is coming. The present invention plays a part in realizing such high-precision processing, and is extremely useful as a method for manufacturing a glass substrate in the future.

  FIG. 4 shows a configuration in which a positioning member 220 that comes into contact with the protrusion of the work holder 100 and a swing clamp 221 as an example of an urging unit are provided as another example of the fixing unit 200. In FIG. 4A, the upper surface of the positioning member 220 is orthogonal to the rotation center of the table 201. By placing the work holder 100 thereon, the rotation of the center axis of the work holder 100 and the table 201 is performed. The center is parallel. As shown in FIG. 4B, the inner hole 220a of the positioning member 220 is provided with two contact protrusions 220b that contact the protrusion 107 on one side, and on the other side across the protrusion 107. Is provided with a moving contact portion 220c.

  The swing clamp 221 is mounted on the table 201, and the cam 221b rotates by rotating the lever 221a. A long hole is provided in the cam 221b, and the moving contact portion 220c is slidably connected. Therefore, by rotating the lever 221a, the moving contact portion 220c advances and retreats with respect to the projection portion 107, and the projection portion 107 is urged to be fixed to the contact projection 220b, or released from being urged. it can.

  Here, the contact protrusion 220b is formed in a shape in which the center of rotation of the table 201 and the center axis of the work holder 100 (that is, the center axis of the laminated glass substrates 10) coincide with the protrusion 107 biased. Has been. That is, even in the configuration of FIG. 4, the work holder 100 can be fixed and mechanically centered at the same time.

  FIG. 5 shows a configuration for centripetal fixing using a screw structure as another example of the fixing means 200. In FIG. 5, the holder receiving member 224 includes a female screw portion 224 a, while a male screw portion 107 a is formed on the outer peripheral surface of the projection 107 of the work holder 100. Note that the fixing means of the polishing apparatus 1 refers only to the holder receiving member 224 and does not include the male screw portion 107a and the protruding portion 107.

  The upper surface of the holder receiving member 224 is orthogonal to the rotation center of the table 201. Accordingly, when the work holder 100 is rotated so that the male screw portion 107a and the female screw portion 224a are screwed together, and the lower surface of the projection 107 comes into contact with the upper surface of the holder receiving member 224, the center axis of the work holder 100 and the rotation center of the table 201 are Are parallel. At this time, the screw structure ensures that the male screw comes to the center of the female screw when fastened. That is, even in the configuration of FIG. 5, the work holder 100 can be fixed and mechanically centered at the same time.

  As described above, according to the configuration of the present invention, the center axis of the glass substrate 10 and the center of rotation of the table 201 can be matched by simply fixing the work holder 100 to the table 201 of the polishing apparatus 1. Therefore, the working time can be shortened and the production cost can be reduced while improving the tolerance and roundness of the inner hole of the glass substrate 10 easily and reliably.

[Example]
Examples of a glass substrate for a magnetic disk and a method for manufacturing the magnetic disk to which the present invention is applied will be described below. This glass substrate for magnetic disk and magnetic disk are 0.8 inch type disk (inner diameter 6 mm, outer diameter 21.6 mm, plate thickness 0.381 mm), 1.0 inch type disk (inner diameter 7 mm, outer diameter 27.4 mm, It is manufactured as a magnetic disk having a predetermined shape such as a plate thickness of 0.381 mm) and a 1.8 inch type magnetic disk (inner diameter of 12 mm, outer diameter of 48 mm, plate thickness of 0.508 mm). Further, it may be manufactured as a 2.5 inch type disc or a 3.5 inch type disc.

(1) Shape processing step and first lapping step In the method of manufacturing a magnetic disk glass substrate according to this example, first, the surface of the plate glass is lapped (ground) to obtain a glass base material. Cut the material and cut out the glass disc. Various plate glasses can be used as the plate glass. This plate-like glass can be manufactured by using a known manufacturing method such as a press method, a float method, a downdraw method, a redraw method, or a fusion method using a molten glass as a material. Of these, plate glass can be produced at low cost by using the pressing method. As the material of the plate glass, amorphous glass or glass ceramics (crystallized glass) can be used. As the material for the plate glass, aluminosilicate glass, soda lime glass, borosilicate glass, or the like can be used. In particular, as an amorphous glass, an aluminosilicate glass can be preferably used in that it can be chemically strengthened and a magnetic disk substrate excellent in flatness of the main surface and substrate strength can be supplied.

In this example, the melted aluminosilicate glass was molded into a disk shape by direct pressing using an upper mold, a lower mold, and a barrel mold to obtain an amorphous plate glass. As the aluminosilicate _glass, SiO 2: 58 to 75 _{wt%, Al} 2 O 3: _{5~23 wt%,} Li 2 O: 3 to 10 _wt%, Na 2 O: 4 to 13 principal component weight% Chemically strengthened glass contained as

  Next, both main surfaces of the plate glass were lapped to form a disk-shaped glass base material. This lapping process was performed using alumina free abrasive grains with a double-sided lapping apparatus using a planetary gear mechanism. Specifically, the lapping platen is pressed on both sides of the plate glass from above and below, the grinding liquid containing free abrasive grains is supplied onto the main surface of the plate glass, and these are moved relative to each other for lapping. went. By this lapping process, a glass base material having a flat main surface was obtained.

(2) Cutting process (coring, forming, chamfering)
Next, the glass base material was cut using a diamond cutter, and a disk-shaped glass substrate was cut out from the glass base material. Next, using a cylindrical diamond drill, an inner hole was formed in the center of the glass substrate to obtain an annular glass substrate (coring). Then, the inner peripheral end face and the outer peripheral end face were ground with a diamond grindstone and subjected to predetermined chamfering (forming, chamfering).

(3) Second Lapping Step Next, a second lapping process was performed on both main surfaces of the obtained glass substrate in the same manner as in the first lapping step. By performing this second lapping step, it is possible to remove in advance the fine unevenness formed on the main surface in the cutting step and end surface polishing step, which are the previous steps, and shorten the subsequent polishing step on the main surface. Will be able to be completed in time.

(4) End surface grinding | polishing process Next, mirror polishing was performed with the brush grinding | polishing method about the outer peripheral end surface of the glass substrate. At this time, as the abrasive grains, a slurry (free abrasive grains) containing cerium oxide abrasive grains was used.

  As for the inner peripheral end face, the work holder 100 in which the plurality of glass substrates 10 are laminated and held as described above is placed on the table 201 of the inner peripheral end face polishing apparatus 1. The work holder 100 is fixed in a direction orthogonal to the central axis of the laminated glass substrate 10 by the fixing means 200 provided on the table 201 so that the central axis of the laminated glass substrate and the rotation axis of the polishing means coincide with each other. . Then, the brush 203 was inserted into the inner hole communicated with the glass substrate 10, and the table 201 and the brush 203 were rotated while the slurry was supplied from the nozzle 207 to polish the inner peripheral end surface of the glass substrate 10.

  And the glass substrate which finished the end surface grinding | polishing process was washed with water. By this end face polishing step, the end face of the glass substrate was processed into a mirror state that can prevent the precipitation of sodium and potassium. In particular, the inner peripheral end face was in a good state without a decrease in tolerance and roundness of the inner hole even when a large number of about 200 to 300 sheets were laminated and polished.

(5) Main surface polishing step As the main surface polishing step, first, a first polishing step was performed. This first polishing step is mainly intended to remove scratches and distortions remaining on the main surface in the lapping step described above. In the first polishing step, the main surface was polished using a hard resin polisher by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, cerium oxide abrasive grains were used.

  The glass substrate which finished this 1st grinding | polishing process was immersed in each washing tank of neutral detergent, a pure water, and IPA (isopropyl alcohol) one by one, and was wash | cleaned.

  Next, a second polishing step was performed as the main surface polishing step. The purpose of this second polishing step is to finish the main surface into a mirror surface. In the second polishing step, mirror polishing of the main surface was performed using a soft foamed resin polisher by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, cerium oxide abrasive grains finer than the cerium oxide abrasive grains used in the first polishing step were used.

  The glass substrate which finished this 2nd grinding | polishing process was immersed in each washing tank of neutral detergent, a pure water, and IPA (isopropyl alcohol) sequentially, and was wash | cleaned. Note that ultrasonic waves were applied to each cleaning tank.

(6) Chemical strengthening process Next, the glass substrate which finished the above-mentioned lapping process and polishing process was chemically strengthened. For chemical strengthening, a chemical strengthening solution prepared by mixing potassium nitrate (60%) and sodium nitrate (40%) is prepared, and the chemically strengthened solution is heated to 400 ° C., and the cleaned glass substrate is preheated to 300 ° C. And was immersed in the chemical strengthening solution for about 3 hours. In this immersion, in order to chemically strengthen the entire surface of the glass substrate, it was performed in a state of being housed in a holder so that a plurality of glass substrates were held at the end surfaces.

  Thus, by immersing in the chemical strengthening solution, the lithium ions and sodium ions in the surface layer of the glass substrate are replaced with sodium ions and potassium ions in the chemical strengthening solution, respectively, and the glass substrate is strengthened. The thickness of the compressive stress layer formed on the surface layer of the glass substrate was about 100 μm to 200 μm.

  The glass substrate that had been subjected to the chemical strengthening treatment was immersed in a 20 ° C. water bath and rapidly cooled, and maintained for about 10 minutes. And the glass substrate which finished quenching was immersed in the concentrated sulfuric acid heated at about 40 degreeC, and was wash | cleaned. Further, the glass substrate after the sulfuric acid cleaning was cleaned by immersing in a cleaning bath of pure water and IPA (isopropyl alcohol) sequentially.

  As described above, a flat and smooth, high-rigidity magnetic disk is obtained by performing the first lapping step, the cutting step, the end surface polishing step, the second lapping step, the first and second polishing steps, and the chemical strengthening step. A glass substrate was obtained.

(7) Magnetic disk manufacturing process On both surfaces of the glass substrate obtained through the above-described processes, an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoTaZr-based alloy, an underlayer made of Ru, and a CoCrPt group on the surface of the glass substrate A perpendicular magnetic recording disk was manufactured by sequentially forming a perpendicular magnetic recording layer made of an alloy, a protective layer made of hydrogenated carbon, and a lubricating layer made of perfluoropolyether. Although this configuration is an example of a configuration of a perpendicular magnetic disk, a magnetic layer or the like may be configured as an in-plane magnetic disk.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  INDUSTRIAL APPLICABILITY The present invention can be used as an inner peripheral end surface polishing apparatus for a magnetic disk glass substrate, a magnetic disk glass substrate manufacturing method, and a magnetic disk manufacturing method.

It is a figure explaining an inner peripheral end surface grinding | polishing apparatus. It is a figure explaining a fixing means. It is a figure explaining a fixing means. It is a figure explaining a fixing means. It is a figure explaining a fixing means. It is a figure which shows the structure of the internal peripheral end surface grinding | polishing apparatus for reference.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polishing apparatus 10 ... Glass substrate 100 ... Work holder 101 ... Lower side support part 104 ... Upper side support part 107 ... Projection part 107a ... Male thread part 200 ... Fixing means 201 ... Table 201a ... Hole 202 ... Base 203 ... Brush 207 ... Nozzle 208 ... Bolt 209 ... Bolt 210 ... Bush 210a ... Inner hole 211 ... Main body 211a ... Step part 212 ... Screw hole 213 ... Screw 214 ... Space 215 ... Gap 216 ... Sleeve 220 ... Positioning member 220a ... Inner hole 220b ... Abutting protrusion 220c ... Moving contact part 221 ... Swing clamp 221a ... Lever 221b ... Cam 224 ... Holder receiving member 224a ... Female thread part

Claims (9)

In the method of manufacturing a glass substrate for a magnetic disk having an inner hole in the center,
The work holder is attached to the table of the inner peripheral end surface polishing apparatus so that the central axis of the plurality of glass substrates stacked on the work holder coincides with the rotation axis of the polishing means for polishing the inner hole communicating with the glass substrate. Fixing, and
And rotating the table and polishing means to polish the inner peripheral end surface of the glass substrate. The step of fixing the work holder to the table of the inner peripheral surface polishing apparatus,
Placing the work holder on the table of the inner peripheral surface polishing apparatus;
The method for manufacturing a glass substrate for a magnetic disk according to claim 1, further comprising a step of fixing the work holder in a direction orthogonal to a central axis of the glass substrates laminated by a fixing means provided on the table. Method. In an inner peripheral end surface polishing apparatus for a glass substrate for a magnetic disk having an inner hole in the center,
A table for supporting a work holder held in a state where a plurality of glass substrates are laminated;
Polishing means for polishing the inner peripheral end surface of the glass substrate by being inserted into the inner hole communicated with the glass substrate and rotating;
Slurry supply means for supplying slurry to the polishing site;
Further, the table includes a fixing means for positioning and fixing the work holder in a direction orthogonal to the central axis of the laminated glass substrates,
The said fixing means fixes a work holder so that the center axis | shaft of the laminated | stacked glass substrate and the rotating shaft of the said grinding | polishing means may correspond, The inner peripheral end surface grinding | polishing apparatus of the glass substrate for magnetic discs characterized by the above-mentioned. 4. The inner circumference of the glass substrate for a magnetic disk according to claim 3, wherein the fixing means positions and fixes the protrusion protruding downward from the work holder in a direction perpendicular to the central axis of the laminated glass substrates. End surface polishing equipment. The said fixing means presses the protrusion part of a work holder from the perimeter direction, and fixes the center axis | shaft of the laminated | stacked glass substrate and the rotating shaft of the said grinding | polishing means to correspond. An apparatus for polishing an inner peripheral end surface of the glass substrate for a magnetic disk according to claim. The said fixing means is provided with the positioning member which contact | abuts to the protrusion part of a work holder from at least 2 directions, and the urging means which urges | biases the protrusion part of a work holder to the said positioning member. Polishing device for inner peripheral surface of glass substrate for magnetic disk. 5. The apparatus for polishing an inner peripheral end surface of a glass substrate for a magnetic disk according to claim 4, wherein the fixing means includes a female screw portion that fits with a male screw portion formed on the outer peripheral surface of the protrusion of the work holder. . In an inner peripheral end surface polishing apparatus for a glass substrate for a magnetic disk having an inner hole in the center,
A table for supporting a work holder held in a state where a plurality of glass substrates are laminated;
Polishing means for polishing the inner peripheral end surface of the glass substrate by being inserted into the inner hole communicated with the glass substrate and rotating;
Slurry supply means for supplying slurry to the polishing site;
Further, the table includes a fixing means for positioning and fixing the work holder,
The fixing means fixes the work holder so that the central axis of the laminated glass substrate and the rotation axis of the polishing means coincide with each other by pressing the protrusion protruding downward from the work holder from the entire circumferential direction. An apparatus for polishing an inner peripheral end face of a glass substrate for a magnetic disk. A method for producing a magnetic disk, comprising forming at least a magnetic layer on a surface of a glass substrate obtained by the method for producing a glass substrate for a magnetic disk according to claim 1.

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