JP2014063543A - Method for manufacturing glass substrate for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass substrate for an information recording medium capable of integrating a glass substrate for an information recording medium into an information recording medium, and then providing a glass substrate for an information recording medium in which the deterioration of recording characteristics does not occur.SOLUTION: In a method for manufacturing a glass substrate for an information recording medium, a process of extracting a polished glass substrate 1G from a polishing pad 310 by using a glass substrate extraction jig 100 includes processes of: inserting the glass substrate extraction jig 100 in a closed state into a hole 11 of the glass substrate 1G from a surface 14 side to a rear face 15 side; putting the glass substrate extraction tool 100 in a state that it is opened to the outside of the radial direction of the glass substrate 1G; and pulling upward the glass substrate 1G by using the glass substrate extraction jig 100 in a state that an annular corner part P1 where the rear face 15 side of the glass substrate 1G and an inner peripheral edge face 13 of the hole 11 cross each other is placed on each of a first holding surface 132a and a second holding surface 142a.

Description

  The present invention relates to a method for producing a glass substrate for an information recording medium.

  Conventionally, an aluminum substrate or a glass substrate is used as an information recording medium (magnetic disk recording medium) used in a computer or the like. A magnetic thin film layer is formed on these substrates, and information is recorded on the magnetic thin film layer by magnetizing the magnetic thin film layer with a magnetic head.

  In recent years, in a hard disk drive (HDD) device, the recording density has been increased. As the recording density is increased, the gap (flying height) between the information recording medium (medium) and the head that reads and writes the recording while floating on the information recording medium is reduced to about several nanometers.

  As the flying height becomes smaller, there are problems such as read / write errors when accessing data recorded on the medium and head crashes when the magnetic head collides with the medium surface when the information recording medium is used in a hard disk drive. It is likely to occur. In order to suppress these problems, since the size of defects on the substrate surface allowed as an information recording medium is also smaller, even as a glass substrate for information recording media, higher surface smoothness has been pursued, In order to suppress foreign matter adhering to the glass substrate surface and undulation of the glass substrate surface, various devices have been devised in the manufacturing method.

  On the other hand, in recent years, the storage capacity of HDDs has been further improved. Currently, a single 2.5-inch recording medium has a recording capacity of 500 GB (single-sided 250 GB) and a surface recording density of 630 Gbit / square inch or more. Things are being developed.

  In the manufacturing process of the glass substrate for information recording media, the process of grind | polishing the surface of a glass substrate using a double-side polish apparatus is employ | adopted. For example, Japanese Patent Laid-Open No. 2010-238291 (Patent Document 1) discloses a jig having a special structure for recovering a polished glass substrate from a lower polishing pad placed on a lower surface plate. Is used.

JP 2010-238291 A

  When the glass substrate after polishing is taken out from the lower polishing pad on the lower surface plate using the jig described above, the glass substrate may be firmly adsorbed to the lower polishing pad. If the adsorbing force for adsorbing the glass substrate by the lower polishing pad is large, a large force is required when taking out the glass substrate from the lower polishing pad.

  At that time, in the jig disclosed in Patent Document 1, after the jig is inserted into the hole of the glass substrate, the diameter of the jig is increased radially outward, and planar friction with the inner peripheral end surface of the hole is achieved. A method of taking out the glass substrate from the lower polishing pad while holding the glass substrate based on the force is employed.

  However, when the jig is firmly pressed into the hole on the inner peripheral end surface of the hole, the polished slurry or the like is pressed against the inner peripheral end surface of the hole and firmly adhered to the inner peripheral end surface. As a result, on the inner peripheral end face, the adherence form of slurry or the like changes to an adherence form stronger than other glass substrate regions, and there is a possibility that it cannot be completely removed in a subsequent cleaning step. As described above, after the glass substrate on which dirt such as slurry is adhered is converted into an information recording medium (magnetic disk), the recording characteristics are deteriorated due to the wraparound of the deposit at the inner peripheral edge. become.

  The present invention has been made in view of the above circumstances, and provides an information recording medium glass substrate that does not cause deterioration in recording characteristics after the information recording medium glass substrate is converted into an information recording medium. An object of the present invention is to provide a method for producing a glass substrate for an information recording medium.

  The manufacturing method of the glass substrate for information recording media based on this invention is a glass substrate for information recording media provided with the grinding | polishing process using the grinding | polishing apparatus which grind | polishes the surface of the glass substrate which has a hole in the center using a polishing pad. A manufacturing method comprising the following steps.

  The polishing step includes a step of placing the glass substrate on the polishing pad, a step of polishing the surface of the glass substrate by the polishing apparatus, and taking out the glass substrate after polishing from the polishing pad. And a step of taking out using a jig.

  The glass substrate take-out jig is connected to be rotatable about a connecting shaft, and is movable between a closed position and an extended position so as to be openable and closable, and the first handle part. A first holding portion having a first enlarged diameter portion provided on one distal end side of the second handle portion, and a first enlarged diameter portion provided on one distal end side of the second handle portion. And a second holding part having a second diameter-expanding part that projects outward in the opposite direction.

  The upper surface of the first enlarged diameter portion has a first holding surface that is inclined downward toward the outside in a state where the first handle portion and the second handle portion are closed, and the second enlarged portion. The upper surface of the diameter portion has a second holding surface that is inclined downward toward the outside in a state where the first handle portion and the second handle portion are closed.

  In the step of taking out the glass substrate after polishing from the polishing pad using the glass substrate take-out jig, the glass substrate take-out jig is closed, and the back surface from the front side to the hole of the glass substrate After being inserted toward the side, the glass substrate take-out jig is opened to the outside in the radial direction of the glass substrate, so that the first holding surface and the second holding surface have the above-mentioned glass substrate. And a step of pulling the glass substrate upward using the glass substrate take-out jig in a state where an annular corner portion where the back surface side and the inner peripheral end surface of the hole intersect is placed.

  In another embodiment, the annular corner is in contact with the first holding surface and the second holding surface by line contact.

  In another embodiment, the annular corner is in contact with the first holding surface and the second holding surface by point contact.

  In another embodiment, the first holding part and the second holding part are further provided with a plurality of cleaning liquid jets for ejecting a cleaning liquid toward the radially outer side of the glass substrate, and polishing is performed from the polishing pad. In the step of taking out the subsequent glass substrate using a glass substrate take-out jig, there is a step of cleaning the inner peripheral end face of the hole by ejecting a cleaning liquid from the cleaning liquid outlet.

  In another embodiment, in the step of cleaning the inner peripheral end face of the hole, the inner peripheral end face is cleaned by applying ultrasonic waves to the cleaning liquid.

  According to the present invention, an information recording medium glass substrate capable of providing a glass substrate for information recording medium that does not cause deterioration in recording characteristics after the information recording medium glass substrate is converted into an information recording medium. It is possible to provide a manufacturing method.

It is a perspective view which shows the glass substrate used for a magnetic disc. It is a perspective view which shows the magnetic disc provided with the glass substrate. It is a flowchart which shows the manufacturing method of the glass substrate in embodiment. It is a fragmentary perspective view of the double-side polish apparatus used for a grinding | polishing process. It is a figure which shows the breakdown of a 2nd polishing process. It is a front view which shows the whole structure of the glass substrate extraction jig | tool in Embodiment 1. FIG. It is the VII-VII line arrow directional view in FIG. 3 is a partially enlarged perspective view showing an external structure of a holding portion of the glass substrate take-out jig in Embodiment 1. FIG. It is a figure which shows the holding | maintenance state of the glass substrate using the glass substrate extraction jig | tool in Embodiment 1. FIG. FIG. 9 is a partial enlarged view showing an external structure of a holding portion of a glass substrate take-out jig in a modification of the first embodiment. FIG. 10 is a partially enlarged perspective view showing an external structure of a holding portion of a glass substrate take-out jig in another modification of the first embodiment. FIG. 10 is a partial enlarged cross-sectional view showing an external structure of a holding part of a glass substrate take-out jig in another modification of the first embodiment. It is an expansion perspective view which shows the external appearance structure of the holding | maintenance part of the glass substrate extraction jig | tool in the other modification of Embodiment 1. FIG. FIG. 10 is an enlarged cross-sectional view showing an external structure of a holding portion of a glass substrate take-out jig in still another modified example of the first embodiment. FIG. 10 is an enlarged cross-sectional view showing an external structure of a holding portion of a glass substrate take-out jig in still another modified example of the first embodiment. 6 is an enlarged perspective view showing an external structure of a holding portion of a glass substrate take-out jig in Embodiment 2. FIG. 6 is a schematic plan view showing a glass substrate holding state in a holding portion of a glass substrate take-out jig in Embodiment 2. FIG. 10 is a cross-sectional view showing a structure of a glass substrate extraction jig in Embodiment 3. FIG. FIG. 10 is a cross-sectional view showing a cleaning state of an inner peripheral end surface of a glass substrate using a glass substrate take-out jig in Embodiment 3. FIG. 6 is a cross-sectional view showing a holding state of a glass substrate using a glass substrate taking out jig in Embodiment 3. It is sectional drawing which shows the structure of the glass substrate extraction jig | tool in Embodiment 4. FIG. It is a figure which shows the evaluation result of the information recording medium (medium) using the glass substrate manufactured in Embodiment 1-4 and the comparative example.

  Embodiments and examples based on the present invention will be described below with reference to the drawings. In the description of the embodiments and examples, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like, unless otherwise specified. In the description of the embodiments and examples, the same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

(Embodiment 1)
(Glass substrate 1G, magnetic disk 1)
With reference to FIG. 1 and FIG. 2, first, a glass substrate 1G obtained by the method for manufacturing a glass substrate for information recording medium according to the present embodiment and a magnetic disk 1 provided with the glass substrate 1G will be described. FIG. 1 is a perspective view showing a glass substrate 1G used for the magnetic disk 1 (see FIG. 2). FIG. 2 is a perspective view showing a magnetic disk 1 provided with a glass substrate 1G as an information recording medium.

  As shown in FIG. 1, a glass substrate 1G (glass substrate for information recording medium) used for a magnetic disk 1 has an annular disk shape with a hole 11 formed in the center. The circular disk-shaped glass substrate 1 </ b> G has a front main surface 14, a back main surface 15, an inner peripheral end surface 13, and an outer peripheral end surface 12. Further, chamfer surfaces 13a and 13b as tapered surfaces are formed on the front main surface 14 side and the back main surface 15 side of the inner peripheral end surface 13, respectively.

  The size of the glass substrate 1G is not particularly limited, and is, for example, an outer diameter of 0.8 inch, 1.0 inch, 1.8 inch, 2.5 inch, or 3.5 inch. The thickness of the glass substrate 1G is, for example, 0.30 mm to 2.2 mm from the viewpoint of preventing breakage. As for the size of the glass substrate 1G in the present embodiment, the outer diameter is about 65 mm, the inner diameter is about 20 mm, and the thickness is about 0.8 mm. The thickness of the glass substrate 1G is a value calculated by averaging the values measured at a plurality of arbitrary points that are point-symmetric on the glass substrate 1G.

  As shown in FIG. 2, in the magnetic disk 1, a magnetic film is formed on the front main surface 14 of the glass substrate 1G, and a magnetic thin film layer 23 including a magnetic recording layer is formed. In FIG. 2, the magnetic thin film layer 23 is formed only on the front main surface 14, but the magnetic thin film layer 23 may also be formed on the back main surface 15.

  The magnetic thin film layer 23 is formed by spin-coating a thermosetting resin in which magnetic particles are dispersed on the front main surface 14 of the glass substrate 1G (spin coating method). The magnetic thin film layer 23 may be formed on the front main surface 14 of the glass substrate 1G by a sputtering method, an electroless plating method, or the like.

  The film thickness of the magnetic thin film layer 23 formed on the front main surface 14 of the glass substrate 1G is about 0.3 μm to about 1.2 μm in the case of the spin coating method, and about 0.04 μm to about 0.00 in the case of the sputtering method. In the case of the electroless plating method, the thickness is about 0.05 μm to about 0.1 μm. From the viewpoint of thinning and high density, the magnetic thin film layer 23 is preferably formed by sputtering or electroless plating.

  The magnetic material used for the magnetic thin film layer 23 is not particularly limited, and a conventionally known material can be used. However, in order to obtain a high coercive force, Co having high crystal anisotropy is basically used for the purpose of adjusting the residual magnetic flux density. A Co-based alloy to which Ni or Cr is added is suitable. Further, as a magnetic layer material suitable for heat-assisted recording, an FePt-based material may be used.

  Further, a lubricant may be thinly coated on the surface of the magnetic thin film layer 23 in order to improve the sliding of the magnetic recording head. Examples of the lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a solvent such as Freon.

  Furthermore, you may provide a base layer and a protective layer as needed. The underlayer in the magnetic disk 1 is selected according to the magnetic film. Examples of the material for the underlayer include at least one material selected from nonmagnetic metals such as Cr, Mo, Ta, Ti, W, V, B, Al, and Ni.

  Further, the underlayer is not limited to a single layer, and may have a multi-layer structure in which the same or different layers are stacked. For example, a multilayer underlayer such as Cr / Cr, Cr / CrMo, Cr / CrV, NiAl / Cr, NiAl / CrMo, or NiAl / CrV may be used.

  Examples of the protective layer that prevents wear and corrosion of the magnetic thin film layer 23 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, and a silica layer. These protective layers can be formed continuously with an in-line type sputtering apparatus, such as an underlayer and a magnetic film. In addition, these protective layers may be a single layer, or may have a multilayer structure including the same or different layers.

  Another protective layer may be formed on the protective layer or instead of the protective layer. For example, instead of the protective layer, colloidal silica fine particles are dispersed and coated on a Cr layer with tetraalkoxysilane diluted with an alcohol solvent, and then fired to form a silicon oxide (SiO2) layer. May be.

(Manufacturing process of glass substrate 1G)
Next, a method for manufacturing the glass substrate 1G and the information recording medium 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a method for manufacturing the glass substrate 1G and the information recording medium 1.

  First, in the “glass melting step” of step 10 (hereinafter abbreviated as “S10”, the same applies to step 11 and subsequent steps), the glass material constituting the glass substrate is melted.

  In the “press molding step” of S11, a glass substrate was produced by pressing the molten glass material using an upper mold and a lower mold. The glass composition used was a general aluminosilicate glass. The method for producing the glass substrate is not limited to molding, and may be cut out from plate glass, which is a known technique, and the glass composition is not limited thereto.

  In the “first lapping step” of S12, both main surfaces of the glass substrate were lapped. This first lapping step was performed using a double-sided lapping device using a planetary gear mechanism. Specifically, the lapping platen was pressed on both surfaces of the glass substrate from above and below, the grinding liquid was supplied onto the main surface of the glass substrate, and these were moved relatively to perform lapping. By this lapping process, a glass substrate having a substantially flat main surface was obtained.

  In the “coring step” of S13, an annular glass substrate was produced by forming a hole in the center of the glass substrate using a cylindrical diamond drill. The inner peripheral end surface and the outer peripheral end surface of the glass substrate were ground with a diamond grindstone, and a predetermined chamfering process was performed.

  In the “second lapping step” of S14, lapping was performed on both main surfaces of the glass substrate in the same manner as in the first lapping step (S12). By performing the second lapping step, the fine uneven shape formed on the main surface in the coring and end face processing in the previous step can be removed in advance. As a result, the polishing time of the main surface in the subsequent process can be shortened.

  In the “outer periphery / inner periphery polishing step” of S15, the outer peripheral end surface and the inner peripheral end surface of the glass substrate were subjected to mirror polishing by brush polishing. At this time, as the abrasive grains, a slurry containing general cerium oxide abrasive grains was used.

In the “first polishing step” of S16, main surface polishing was performed. The first polishing step is mainly intended to correct scratches and warpage remaining on the main surface in the first and second lapping steps (S12, S14) described above. In the first polishing step, the main surface was polished by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, general cerium oxide abrasive grains were used.

  In the “chemical strengthening step” of S17, a surface reinforcing layer was formed on the main surface of the glass substrate 1G. Specifically, chemical strengthening was performed by bringing the glass substrate 1G into contact with a mixed solution of potassium nitrate (70%) and sodium nitrate (30%) heated to 300 ° C. for about 30 minutes. As a result, the lithium ion and sodium ion on the inner peripheral end surface and outer peripheral end surface of the glass substrate are respectively replaced with sodium ions and potassium ions in the chemical strengthening solution, and a compressive stress layer is formed, thereby forming the main surface of the glass substrate and The end face was strengthened.

  In the “second polishing step” of S18, a main surface polishing step was performed. This second polishing step aims to eliminate the fine defects on the main surface that have been generated and remain in the above-described steps and finish it in a mirror shape, to eliminate warpage and finish it to a desired flatness. In the second polishing step, polishing was performed by a double-side polishing apparatus having a planetary gear mechanism. As the abrasive, colloidal silica having an average particle diameter of about 20 nm was used to obtain a smooth surface.

  Next, in the “Final Cleaning” of S19, final cleaning of the main surface and the end surface of the glass substrate is performed. Thereby, the deposits remaining on the glass substrate are removed. The final cleaning process is a process performed at the end of the glass substrate manufacturing process, and includes a drying process as appropriate.

  The manufacturing method of the glass substrate in this Embodiment is comprised as mentioned above. The glass substrate 1G shown in FIG. 1 is obtained by using this glass substrate manufacturing method. Thereafter, the information recording medium 1 shown in FIG. 2 is obtained using the glass substrate 1G thus obtained.

  In addition, as a magnetic thin film layer film forming step in the manufacture of the information recording medium, after cleaning the glass substrate 1G obtained through the above-described steps, an adhesion layer made of a Cr alloy, a CoFeZr alloy is formed on both main surfaces of the glass substrate 1G. Information recording in a perpendicular magnetic recording system by sequentially forming a soft magnetic layer made of Ru, an orientation control underlayer made of Ru, a perpendicular magnetic recording layer made of a CoCrPt alloy, a protective layer made of C, and a lubricating layer made of F Produce media. This configuration is an example of a configuration of a perpendicular magnetic recording system, and a magnetic layer or the like may be configured as an in-plane information recording medium. Thereafter, the information recording medium 1 is completed by performing a heat treatment step and the like.

  Next, with reference to FIG. 4 to FIG. 9, a step of taking out the glass substrate after polishing from the double-side polishing apparatus in the second polishing step (S18) which is the final polishing step in the present embodiment will be described. FIG. 4 is a partial perspective view of a double-side polishing apparatus used in the polishing process, FIG. 5 is a diagram showing a breakdown of the second polishing process, and FIG. 6 shows the entire structure of the glass substrate extraction jig in the present embodiment. FIG. 7 is a front view, FIG. 7 is a view taken along arrow VII-VII in FIG. 6, FIG. 8 is a partially enlarged perspective view showing the external structure of the holding portion of the glass substrate take-out jig in the present embodiment, and FIG. It is a figure which shows the holding state of the glass substrate using the glass substrate extraction jig | tool in this Embodiment.

  First, a schematic configuration of the double-side polishing apparatus 2000 will be described with reference to FIG. FIG. 4 is a partial perspective view of a double-side polishing apparatus 2000 used in the polishing process.

  The double-side polishing apparatus 2000 includes an upper surface plate (upper whetstone holding surface plate) 300, a lower surface plate (lower whetstone holding surface plate) 400, and a side (glass substrate side) facing the lower surface plate 400 of the upper surface plate 300. The upper polishing pad 310 mounted on the lower surface and the lower polishing pad 410 mounted on the upper surface on the side facing the upper surface plate 300 (glass substrate side) of the lower surface plate 400 are provided.

  The upper polishing pad 310 and the lower polishing pad 410 are processing members for polishing both main surfaces of the glass substrate 1G. The upper surface plate 300 and the lower surface plate 400 rotate in directions opposite to each other with respect to the revolution direction of the carrier 500. A surface of the upper polishing pad 310 facing the lower surface plate 400 forms an upper polishing surface 311. The surface of the lower polishing pad 410 facing the upper surface plate 300 forms a lower polishing surface 411. Carrier 500 is arranged in a gap formed between upper surface plate 300 and lower surface plate 400. A plurality of disk-shaped glass substrates 1 are held by the carrier 500.

  Glass substrate 1G is sandwiched between upper surface plate 300 and lower surface plate 400, and stress is applied in the thickness direction of the glass substrate by upper surface plate 300 and lower surface plate 400. As a result, both main surfaces of the glass substrate are pressed against the polishing surface 311 of the upper polishing pad 310 and the polishing surface 411 of the lower polishing pad 410. In this state, the polishing surface 311 of the upper polishing pad 310 moves relative to one main surface of the glass substrate, whereby the one main surface is polished. At the same time, the polishing surface 411 of the lower polishing pad 410 moves relative to the other main surface of the glass substrate, whereby the other main surface is polished. In this manner, both main surfaces of the glass substrate are simultaneously polished using the double-side polishing apparatus 2000.

  After precision polishing using the double-side polishing apparatus 2000, the glass substrate 1 adhered to the polishing surface 311 of the upper polishing pad 310 and the polishing surface 411 of the lower polishing pad 410 is taken out from the polishing pad.

  Referring to FIG. 5, the second polishing step S18 includes a carrier placement step (S181), a glass substrate placement step (S182), a polishing step (S183), a glass substrate removal step (S184), and a carrier removal step (S185). have.

(Glass substrate extraction jig 100)
With reference to FIGS. 6 to 9, the structure of the glass substrate extraction jig 100 used in the glass substrate extraction step S334 and the glass substrate extraction step (S184) using the glass substrate extraction jig 100 will be described.

  With reference to FIGS. 6 to 8, the glass substrate take-out jig 100 is connected so as to be rotatable about a connection axis R <b> 1, and a closed position (position shown in FIG. 6) and an expanded position (see FIG. 9). A first handle portion 110 and a second handle portion 120 that can be opened and closed. The material of the first handle part 110 and the second handle part 120 may be any material as long as it has rigidity.

  A first holding part 130 made of a resin material or the like is provided on one tip side of the first handle part 110. The first holding part 130 includes a first base part 131 that is fixed to the tip of the first handle part 110, and a first enlarged diameter part 132 that is provided integrally with the first base part 131 and projects outward. And have. An annular grip 150 is provided on the other side of the first handle 110.

  A second holding part 140 made of a resin material or the like is provided on one tip side of the second handle part 120. The second holding part 140 is provided integrally with the second base part 141 fixed to the tip of the second handle part 120 and the second base part 141, and is opposite to the first diameter-expanding part 132 described above. And a second enlarged-diameter portion 142 projecting toward the outside. On the other side of the second handle 120, an annular grip 160 is provided.

  The outer surface 131a of the first base portion 131 has a semicylindrical shape. The upper surface of the first enlarged diameter portion 132 has a first holding surface 132a that inclines downward toward the outer side opposite to the second enlarged diameter portion 142, and has a semiconical shape as a whole.

  The outer surface 141a of the second base portion 141 has a semicylindrical shape. The upper surface of the second enlarged diameter portion 142 has a second holding surface 142a that inclines downward toward the outer side opposite to the first enlarged diameter portion 132, and has a semiconical shape as a whole.

  In the present embodiment, when the glass substrate extraction jig 100 shown in FIGS. 6 to 8 is closed, the first base portion 131 of the first holding portion 130 and the second base portion 141 of the second holding portion 140 are used. And the first enlarged portion 132 and the second enlarged portion 142 are overlapped to give a conical appearance.

  Next, with reference to FIG. 9, the glass substrate extraction process (S184) using the glass substrate extraction jig | tool 100 which has the said structure is demonstrated.

  First, the glass substrate extraction jig 100 is closed, and the glass substrate extraction jig 100 is inserted into the hole 11 of the glass substrate 1G from the front main surface 14 side to the back main surface 15 side. Then, as shown in FIG. 9, the glass substrate extraction jig 100 is opened to the outside in the radial direction of the glass substrate 1G.

  Thereby, the annular corner P1 where the back main surface 15 side of the glass substrate 1G and the inner peripheral end surface 13 of the hole 11 intersect is placed on the first holding surface 132a and the second holding surface 142a. Thereafter, the glass substrate 1G is pulled upward using the glass substrate extraction jig 100. In the glass substrate 1G in the present embodiment, chamfer surfaces 13a and 13b are formed as tapered surfaces on the front main surface 14 side and the back main surface 15 side of the inner peripheral end surface 13, respectively. Therefore, in the present embodiment, the annular corner portion P1 is defined by a region where the back main surface 15 side and the chamfer surface 13b corresponding to the inner peripheral end surface 13 of the hole 11 intersect.

  Thereby, the annular corner P1 is in line contact with the first holding surface 132a and the second holding surface 142a (point contact when viewed in cross section), and the first holding surface 132a and the second holding surface 142a Without applying a large pressure between the glass substrate 1G and the contact area between the first holding surface 132a and the second holding surface 142a and the glass substrate 1G is reduced, the glass substrate 1G is pulled upward. Is possible. As a result, it becomes possible to prevent the polished slurry and the like from being pressed against the inner peripheral end surface 13 of the hole 11 and firmly attached to the inner peripheral end surface 13.

  Further, even when the glass substrate 1G obtained in this way is used as an information recording medium (magnetic disk), the deposits on the glass substrate 1G are reduced, so that the recording characteristics are deteriorated. Nor.

  In addition, although the said glass substrate extraction jig | tool 100 demonstrated the case where the 2 division | segmentation structure which divides a holding part into the 1st holding | maintenance part 130 and the 2nd holding | maintenance part 140 was employ | adopted, it is not limited to a 2 division | segmentation structure It is also possible to adopt a division structure of three divisions, four divisions, or more.

(Modification: Glass substrate extraction jig 100A)
Next, with reference to FIG. 10, a glass substrate extraction jig 100A as a modification of the glass substrate extraction jig 100 will be described. FIG. 10 is a partially enlarged perspective view showing the external structure of the holding portion of the glass substrate extraction jig 100A.

  In the glass substrate extraction jig 100, the first base portion 131 of the first holding portion 130 and the second base portion 141 of the second holding portion 140 are overlapped when the glass substrate extraction jig 100 is closed. In this way, a cylindrical appearance was exhibited, and the first enlarged portion 132 and the second enlarged portion 142 were overlapped to give a conical appearance, but the glass substrate extraction jig 100A shown in FIG. The glass substrate take-out jig 100 is partially cut out in a rectangular shape, and the first base portion 131 of the first holding portion 130A and the second base portion 141 of the second holding portion 140A are overlapped. It has a substantially rectangular appearance, and the first enlarged diameter portion 132 of the first holding portion 130A and the second enlarged diameter portion 142 of the second holding portion 140A are overlapped to give a substantially rectangular appearance.

  Similarly to the glass substrate extraction step (S184) using the glass substrate extraction jig 100 shown in FIG. 9, the glass substrate extraction jig 100A having this shape also has the first holding surface 132a and the second holding surface 142a. The annular corner P1 where the back main surface 15 side of the glass substrate 1G and the inner peripheral end face 13 of the hole 11 intersect can be placed in a line contact state (point contact when viewed in cross section). . As a result, the same effect as the glass substrate extraction jig 100 can be obtained by the glass substrate extraction jig 100A.

(Other modifications: glass substrate extraction jig 100B)
Next, with reference to FIG. 11 to FIG. 13, a glass substrate extraction jig 100B as another modification of the glass substrate extraction jig 100 will be described. 11 is a partially enlarged perspective view showing the external structure of the holding portion of the glass substrate extraction jig 100B. FIG. 12 is a partial enlarged cross-sectional view showing the external structure of the holding portion of the glass substrate extraction jig 100B. These are expansion perspective views which show the external appearance structure of the holding | maintenance part of the glass substrate extraction jig | tool 100B.

  In the glass substrate unloading jig 100, the first holding surface 132a of the first enlarged diameter portion 132 has a conical surface. However, in the glass substrate unloading jig 100B, the first holding surface 132b of the first holding portion 130B. Has a concave surface that curves downward. In addition, the second holding surface 142b of the second holding unit 140B also has a concave surface that curves downward. Other forms are the same as those of the glass substrate extraction jig 100.

  Also in the glass substrate take-out jig 100B having this shape, as shown in FIG. 13, the first holding surface 132b and the second holding surface 142b are provided on the back main surface 15 side of the glass substrate 1G and the inner peripheral end surface 13 of the hole 11. Can be placed in a state of line contact (point contact when viewed in a cross section). As a result, the same effect as the glass substrate extraction jig 100 can be obtained by the glass substrate extraction jig 100B.

  In addition, it is also possible to deform | transform this glass substrate extraction jig | tool 100B into the external appearance form similar to 100A of glass substrate extraction jig | tool shown in FIG.

(Still another modified example: glass substrate taking out jig 100C)
Next, with reference to FIG. 14, a glass substrate extraction jig 100C as still another modified example of the glass substrate extraction jig 100 will be described. FIG. 14 is an enlarged cross-sectional view showing the external structure of the holding portion of the glass substrate extraction jig 100C.

  The glass substrate take-out jig 100C includes a third holding surface 133a facing the first holding surface 132a in a region facing the upper side of the first enlarged diameter portion 132 having the first holding surface 132a in the first holding portion 130C. The 3rd enlarged diameter part 133 which has is provided. The third holding surface 133a is inclined upwardly toward the outer side opposite to the second holding portion 140C.

  Similarly, in the second holding portion 140C, a fourth diameter expansion having a fourth holding surface 143a facing the second holding surface 142a in a region facing the upper side of the second diameter expanding portion 142 having the second holding surface 142a. A portion 143 is provided. The fourth holding surface 143a is inclined upward toward the outer side opposite to the first holding portion 130C.

  In the glass substrate extraction jig 100 </ b> C having this configuration, the functions of the first holding surface 132 a and the second holding surface 142 a are the same as those of the glass substrate extraction jig 100. Here, when the glass substrate 1G of the first holding surface 132a and the second holding surface 142a is placed, the glass substrate 1G slides upward along the slopes of the first holding surface 132a and the second holding surface 142a. It is possible.

  In this case, according to the glass substrate take-out jig 100C, the third holding surface 133a and the fourth holding surface 143a are provided. Therefore, the glass substrate 1G is provided on the third holding surface 133a and the fourth holding surface 143a. The annular corner P2 where the inner peripheral end surface 13 and the chamfer surface 13a intersect can be brought into contact with each other in a line contact state (point contact when viewed in a cross section).

  Also in the glass substrate extraction jig 100C having this shape, as shown in FIG. 14, the back of the glass substrate 1G is placed on the first holding surface 132a and the second holding surface 142a as in the case of the glass substrate extraction jig 100. The annular corner P1 where the main surface 15 side and the inner peripheral end face 13 of the hole 11 intersect can be placed in a line contact state (point contact when viewed in a cross section). As a result, the same effect as the glass substrate extraction jig 100 can be obtained by the glass substrate extraction jig 100C.

  Further, an annular corner P2 where the inner peripheral end surface 13 of the glass substrate 1G and the chamfer surface 13a intersect with the third holding surface 133a and the fourth holding surface 143a is in line contact (point contact when viewed in cross section). Therefore, the movement of the glass substrate 1G can be suppressed when the glass substrate 1G is held by the glass substrate extraction jig 100C.

  It should be noted that the glass substrate extraction jig 100C can be modified in the same manner as the glass substrate extraction jig 100B and the glass substrate extraction jig 100C.

(Still another modification: glass substrate take-out jig 100D)
Next, with reference to FIG. 15, a glass substrate extraction jig 100D as still another modification of the glass substrate extraction jig 100 will be described. FIG. 15 is an enlarged cross-sectional view showing the external structure of the holding portion of the glass substrate extraction jig 100D.

  When the glass substrate extraction jig 100D is compared with the configuration of the glass substrate extraction jig 100C, the first holding surface 132a and the third holding surface 133a are directly intersected with each other in the first holding portion 130D. A substantially V-shaped holding surface is formed. Similarly, in the second holding portion 140D, the second holding surface 142a and the fourth holding surface 143a directly intersect to form a substantially V-shaped holding surface in a cross-sectional view.

  According to the glass substrate extraction jig 100 </ b> D having this configuration, the same effects as those of the glass substrate extraction jig 100 </ b> C can be obtained. Also, the glass substrate extraction jig 100D can be modified in the same manner as the glass substrate extraction jig 100B and the glass substrate extraction jig 100C.

(Embodiment 2: Glass substrate extraction jig 100E)
Next, with reference to FIG. 16 and FIG. 17, the glass substrate extraction jig | tool 100E in Embodiment 2 is demonstrated. Note that the glass substrate extraction jigs 100 to 100D in the first embodiment are different from each other only in the structure of the first holding unit 130E and the second holding unit 140E, and the other configurations are the same. The structures of the first holding unit 130E and the second holding unit 140E will be described in detail. FIG. 16 is an enlarged perspective view showing the external structure of the holding part of the glass substrate extraction jig 100E, and FIG. 17 is a schematic plan view showing the holding state of the glass substrate in the holding part of the glass substrate extraction jig 100E.

  Referring to FIG. 16, this glass substrate take-out jig 100E has a structure similar to that of glass substrate take-out jig 100A shown in FIG. 10, but the outer surface of first base portion 131e of first holding portion 130E. And the 1st holding surface 132f of the 1st enlarged diameter part 132e has a flat surface shape. Similarly, the outer surface of the second base portion 141e of the second holding portion 140E and the second holding surface 142f of the second enlarged diameter portion 142e also have a flat surface shape.

  As a result, as shown in FIG. 17, when the glass substrate 1G is held using the glass substrate take-out jig 100E, the first holding surface 132f and the second holding surface 142f are in contact with the annular corner portion P1. The locations hold the glass substrate 1G by the first holding surface 132f and the second holding surface 142f in two point contact states, respectively.

  Thereby, it is possible to pull the glass substrate 1G upward while further reducing the contact area between the first holding surface 132a and the second holding surface 142a and the glass substrate 1G. As a result, it is possible to further suppress the polishing slurry and the like from being pressed against the inner peripheral end surface 13 of the hole 11 and firmly attached to the inner peripheral end surface 13.

  In addition, although the said glass substrate extraction jig | tool 100E demonstrated the case where the 2 division | segmentation structure which divides a holding part into the 1st holding | maintenance part 130E and the 2nd holding | maintenance part 140E was employ | adopted, it is not limited to a 2 division | segmentation structure It is also possible to adopt a division structure of three divisions, four divisions, or more.

  Moreover, it is also possible to apply to this glass substrate extraction jig | tool 100E the modification applied to the glass substrate extraction jig | tool 100B, 100C, 100D mentioned above.

(Embodiment 3: Glass substrate extraction jig 100F)
Next, with reference to FIG. 18 to FIG. 20, a glass substrate extraction jig 100F in the third embodiment will be described. In addition, glass substrate extraction jig 100F in the present embodiment employs a configuration in which a cleaning liquid can be ejected outward in the radial direction of glass substrate 1G to the first holding unit and the second holding unit. The configuration of the glass substrate extraction jig itself is the same as that of the glass substrate extraction jig 100, 100A to 100E.

  Here, the case where the configuration capable of ejecting the cleaning liquid is applied to the glass substrate extraction jig 100D shown in FIG. 15 will be described below. However, all the other glass substrate extraction jigs 100, 100A, 100B described above are used. , 100C, 100E can be applied with a configuration capable of ejecting the cleaning liquid described below.

  18 is a cross-sectional view showing the structure of the glass substrate take-out jig 100F, FIG. 19 is a cross-sectional view showing the cleaning state of the inner peripheral end surface of the glass substrate 1G using the glass substrate take-out jig 100F, and FIG. It is sectional drawing which shows the holding | maintenance state of the glass substrate using the board | substrate extraction jig | tool 100F.

  Referring to FIG. 18, the basic structure of glass substrate extraction jig 100F is the same as glass substrate extraction jig 100D shown in FIG. 15, and a cleaning liquid ejection mechanism 200 is further added. In the cleaning liquid ejection mechanism 200, one end is connected to the first conduit 210 and the other end is the first in the first conduit 210 disposed inside the first handle 110 and the first holding portion 130D. It has a plurality of jet lines 220 that are exposed to the holding surface 132a and the third holding surface 133a and that constitute a cleaning liquid jet port.

  Similarly, in the 1st pipe line 210 arrange | positioned inside the 2nd handle | pattern part 120, and the inside of 2nd holding | maintenance part 140D, one end is connected with the 1st pipe line 210, and the other end is 2nd holding surface 142a and It has a plurality of ejection pipes 220 that are exposed to the fourth holding surface 143a and constitute a cleaning liquid ejection port.

  In the present embodiment, the ejection pipe line 220 is arranged in the ejection pipe line 220 so that the cleaning liquid is concentrated on the inner peripheral end surface of the glass substrate 1G in the first holding part 130D and the second holding part 140D. Each is provided so as to be inclined at a predetermined angle.

  A cleaning liquid supply device 230 for supplying a cleaning liquid to the first pipe line 210 and the ejection pipe line 220 is connected to the other end side of the first pipe line 210.

  Next, with reference to FIG. 19 and FIG. 20, the glass substrate extraction process (S184: refer FIG. 5) using the glass substrate extraction jig | tool 100F which has the said structure is demonstrated.

  Referring to FIG. 19, glass substrate extraction jig 100F is closed, and glass substrate extraction jig 100E is inserted into hole 11 of glass substrate 1G from the front main surface 14 side to the back main surface 15 side. . Next, the cleaning liquid supply device 230 is driven to supply the cleaning liquid to the first pipe line 210 and the ejection pipe line 220. As the cleaning liquid, for example, a solution obtained by diluting the polycarboxylic acid for dispersing the colloidal silica abrasive used in the polishing step S183 (see FIG. 5) to 2% is sprayed on the inner peripheral end face 13 of the glass substrate 1G for about 5 seconds.

  Referring to FIG. 20, glass substrate extraction jig 100E is opened to the outside in the radial direction of glass substrate 1G.

  Thereby, in the glass substrate extraction step (S184), after the inner peripheral end face 13 of the glass substrate 1G is cleaned, the glass substrate 1G is extracted in the same manner as the glass substrate extraction jig 100D shown in FIG. 20 in the direction of arrow D).

(Embodiment 4: Glass substrate extraction jig 100G)
Next, with reference to FIG. 21, the glass substrate extraction jig | tool 100G in Embodiment 4 is demonstrated. FIG. 21 is a cross-sectional view showing the structure of the glass substrate extraction jig 100G. The basic configuration of the glass substrate extraction jig 100G is the same as that of the glass substrate extraction jig 100F. The difference is that an ultrasonic application device 240 is added to the cleaning liquid ejection mechanism 200.

  When the cleaning liquid supply device 230 is driven to supply the cleaning liquid to the first pipe line 210 and the ejection pipe line 220, an ultrasonic wave of 1 MHz is applied to the cleaning liquid using the ultrasonic wave application device 240. Thereby, it becomes possible to improve the cleaning efficiency of the inner peripheral end face 13 of the glass substrate 1G using the glass substrate extraction jig 100F.

(quality evaluation)
The glass substrate extraction jig 100 disclosed in the first embodiment, the glass substrate extraction jig 100E disclosed in the second embodiment, 100F disclosed in the third embodiment, and the glass substrate extraction jig disclosed in the fourth embodiment. A read and write test on an information recording medium (medium) by forming a magnetic film having a surface recording density of 630 Gb / in 2 or more on a glass substrate 1G manufactured using the tool 100G (error occurrence rate) (N = 100)). Evaluation of the test results is shown in FIG.

  The test result on the information recording medium (medium) using the glass substrate 1G manufactured according to the first embodiment has an error rate of 1%, and the evaluation is “B”, which is a usable level. It was.

  The test result with the information recording medium (medium) using the glass substrate 1G manufactured according to the second embodiment shows that the error rate is 0.7%, and the evaluation is “B”, which is a usable level. Met.

  The test result with the information recording medium (medium) using the glass substrate 1G manufactured according to the third embodiment shows that the error occurrence rate is 0.5%, and the evaluation is a sufficiently usable level “A "Met.

  The test result on the information recording medium (medium) using the glass substrate 1G manufactured according to the fourth embodiment shows that the error occurrence rate is 0.1%, and the evaluation is a sufficiently usable level “A "Met.

  In the comparative example, the glass substrate 1G was used in which a jig was brought into surface contact with the inner peripheral end surface 13 of the glass substrate 1G and the glass substrate 1G was taken out based on the frictional force. As a result, the test result on the information recording medium (medium) using the glass substrate 1G has a high error occurrence rate of 2%, and the evaluation is “C” which is a level not suitable for actual use. .

  As mentioned above, the evaluation result in each embodiment was a favorable result with respect to the comparative example. In the comparative example, the glass substrate take-out jig is brought into surface contact with the inner peripheral end surface 13 of the glass substrate 1G and the glass substrate 1G is held by a frictional force. Since it changed into a form, the evaluation result is “C”.

  On the other hand, the glass substrate take-out jig in each embodiment holds the glass substrate from below by line contact or point contact without bringing the glass substrate take-out jig into surface contact with the inner peripheral end surface 13 of the glass substrate 1G. Thus, the glass substrate is taken out. As a result, the deposit on the inner peripheral end surface is not pressed against the inner peripheral end surface 13 of the hole 11, and the adhesion of the deposit on the inner peripheral end surface 13 is suppressed. In addition, compared with the first embodiment (line contact), the second embodiment (point contact) has fewer contact portions with the inner peripheral end face 13, and the quality evaluation is improved accordingly.

  Compared to the second embodiment (point contact), the third embodiment (point contact + cleaning) has fewer contact parts with the inner peripheral end face 13 and is cleaned, so the quality is improved. Evaluation has also improved. Furthermore, compared with the third embodiment (point contact + cleaning), the fourth embodiment (point contact + ultrasonic cleaning) reduces the number of contact portions with the inner peripheral end face 13 and performs ultrasonic cleaning. As a result, the quality evaluation has also improved.

  In the above embodiment, the case where the double-side polishing apparatus is used has been described. However, the present invention is not limited to the double-side polishing apparatus.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Magnetic disk, 1G glass substrate, 11 hole, 12 Outer peripheral end surface, 13 Inner peripheral end surface, 13a, 13b Chamfer surface, 14 Front main surface, 15 Back main surface, 23 Magnetic thin film layer, 100, 100A, 100B, 100C, 100D , 100E, 100F, 100G Glass substrate extraction jig, 110 1st handle, 120 2nd handle, 130, 130A, 130B, 130C, 130D, 130E 1st holding part, 131 1st base part, 131a, 141a outside Surface, 131e 1st base part, 132 1st enlarged diameter part, 132a, 132b, 132f 1st holding surface, 132e 1st enlarged diameter part, 133 3rd enlarged diameter part, 133a 3rd holding surface, 140, 140A, 140B , 140C, 140D, 140E second holding portion, 141, 141e second base portion, 142 second diameter expanding portion 142a, 142f 2nd holding surface, 142e 2nd enlarged diameter part, 143 4th enlarged diameter part, 143a 4th holding surface, 150,160 grip part, 200 washing | cleaning liquid ejection mechanism, 210 1st pipe line, 220 ejection pipe line, 230 cleaning liquid supply device, 240 ultrasonic application device, 300 upper surface plate (upper grinding wheel holding surface plate), 310 upper polishing pad, 311 polishing surface, 400 lower surface plate (lower grinding wheel holding surface plate), 410 lower polishing pad, 411 polishing surface, 500 carrier, 2000 double-side polishing apparatus, R1 connecting shaft, P1, P2 annular corners.

Claims (5)

A method for producing a glass substrate for an information recording medium, comprising a polishing step using a polishing apparatus that polishes the surface of a glass substrate having a hole in the center using a polishing pad,
The polishing step includes
Placing the glass substrate on the polishing pad;
Polishing the surface of the glass substrate by the polishing apparatus;
The step of taking out the glass substrate after polishing from the polishing pad using a glass substrate take-out jig,
The glass substrate take-out jig is
A first handle portion and a second handle portion that are pivotally connected about a connecting shaft and movable between a closing position and an expanding position so as to be openable and closable;
A first holding portion provided on one tip side of the first handle portion and having a first diameter-expanded portion projecting outward;
A second holding part provided on one tip side of the second handle part and having a second enlarged diameter part projecting outward in the direction opposite to the first enlarged diameter part,
On the upper surface of the first enlarged diameter portion, in a state where the first handle portion and the second handle portion are closed, the first holding surface is inclined downward toward the outside,
On the upper surface of the second enlarged diameter portion, in a state where the first handle portion and the second handle portion are closed, it has a second holding surface that is inclined downward toward the outside,
In the step of taking out the glass substrate after polishing from the polishing pad using the glass substrate take-out jig,
After the glass substrate take-out jig was closed and inserted through the hole of the glass substrate from the front side to the back side, the glass substrate take-out jig was opened outward in the radial direction of the glass substrate. By making the state, an annular corner portion where the back surface side of the glass substrate and the inner peripheral end surface of the hole intersect is placed on the first holding surface and the second holding surface, The manufacturing method of the glass substrate for information recording media including the process of pulling up a glass substrate upwards using the said glass substrate extraction jig | tool.   The method for manufacturing a glass substrate for an information recording medium according to claim 1, wherein the annular corner portion is in contact with the first holding surface and the second holding surface by line contact.   The method of manufacturing a glass substrate for an information recording medium according to claim 1, wherein the annular corner portion, the first holding surface, and the second holding surface are in contact with each other by point contact. The first holding part and the second holding part are further provided with a plurality of cleaning liquid jets for jetting a cleaning liquid toward the radially outer side of the glass substrate,
In the step of taking out the glass substrate after polishing from the polishing pad using a glass substrate take-out jig,
The manufacturing method of the glass substrate for information recording media in any one of Claim 1 to 3 which has the process of ejecting a washing | cleaning liquid from the said washing | cleaning-liquid ejection port, and wash | cleaning the said inner peripheral end surface of the said hole.   5. The method for manufacturing a glass substrate for an information recording medium according to claim 4, wherein the step of cleaning the inner peripheral end surface of the hole performs cleaning of the inner peripheral end surface by applying an ultrasonic wave to the cleaning liquid.

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