WO2015041011A1 - 情報記録媒体用ガラス基板の製造方法 - Google Patents
情報記録媒体用ガラス基板の製造方法 Download PDFInfo
- Publication number
- WO2015041011A1 WO2015041011A1 PCT/JP2014/072303 JP2014072303W WO2015041011A1 WO 2015041011 A1 WO2015041011 A1 WO 2015041011A1 JP 2014072303 W JP2014072303 W JP 2014072303W WO 2015041011 A1 WO2015041011 A1 WO 2015041011A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- glass substrate
- cleaning
- information recording
- recording medium
- peripheral end
- Prior art date
Links
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
Definitions
- the present invention relates to a method for producing a glass substrate for an information recording medium.
- a 2.5-inch recording medium has a recording capacity of 500 GB (single-sided 250 GB) and a surface recording density of 630 Gb / square inch or more. Those having a recording density have been developed.
- the distance (flying height) between the magnetic head and the magnetic disk is becoming smaller.
- the flying height becomes smaller, in order to suppress defects (head crashes) caused by the magnetic disk, requirements for the cleanliness of the substrate surface that is allowed as the magnetic disk and the flatness of the substrate surface have become stricter. .
- Patent Document 1 discloses a magnetic disk formed by adopting a chemical strengthening process.
- the HDD device does not operate when a larger impact than expected is applied.
- the magnetic disk in the HDD device is damaged in the event of an impact such as dropping.
- the present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a glass substrate for an information recording medium, which can further improve the strength of a magnetic disk.
- the glass substrate for information recording media has one main surface, the other main surface, an inner peripheral end surface that defines a hole, and an outer peripheral end surface, and a disc-shaped glass substrate as a whole.
- the step of molding, the step of polishing the inner end with cerium oxide on the inner peripheral end surface, the step of cleaning the glass substrate, and the surface of the glass substrate after cleaning the glass substrate And the step of cleaning the glass substrate is performed such that the amount of cerium oxide residue of ⁇ 0.1 ⁇ m or more is 3 pieces / mm 2 or less on the inner peripheral end face of the glass substrate.
- the process of performing is included.
- the step of cleaning the glass substrate is performed by inserting a vibrating rod into the hole and applying ultrasonic waves to the vibrating rod while the glass substrate is immersed in a cleaning solution.
- the glass substrate is cleaned by vibrating the vibrating bar.
- the glass substrate is cleaned while a brush is attached to the vibrating rod and the brush is in contact with the inner peripheral end surface.
- At least one precision polishing step is included.
- the glass substrate has a thickness of 0.65 mm or less.
- the method for manufacturing a glass substrate for information recording medium based on the present invention, it is possible to provide a method for manufacturing a glass substrate for information recording medium, which can further improve the strength of the magnetic disk.
- FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is a top view which shows the information recording medium provided with the glass substrate as an information recording medium.
- FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. It is a flowchart which shows the manufacturing method of a glass substrate. It is a schematic diagram which shows the subject which arises in the manufacturing method of a glass substrate. It is a schematic diagram of the washing
- FIG. 1 is a perspective view showing the information recording apparatus 30.
- the information recording apparatus 30 includes the glass substrate 1 manufactured by the method for manufacturing a glass substrate for information recording medium (hereinafter also simply referred to as a glass substrate) in the embodiment as the information recording medium 10.
- the information recording device 30 includes an information recording medium 10, a housing 20, a head slider 21, a suspension 22, an arm 23, a vertical shaft 24, a voice coil 25, a voice coil motor 26, a clamp member 27, and a fixing screw. 28.
- a spindle motor (not shown) is installed on the upper surface of the housing 20.
- An information recording medium 10 such as a magnetic disk is rotatably fixed to the spindle motor by a clamp member 27 and a fixing screw 28.
- the information recording medium 10 is rotationally driven by this spindle motor at, for example, several thousand rpm.
- a compression stress layer 12 see FIG. 5
- a magnetic recording layer 14 see FIGS. 4 and 5 are formed on the glass substrate 1. To be manufactured.
- the arm 23 is attached so as to be swingable around the vertical axis 24.
- a suspension 22 formed in a leaf spring (cantilever) shape is attached to the tip of the arm 23.
- a head slider 21 is attached to the tip of the suspension 22 so as to sandwich the information recording medium 10.
- a voice coil 25 is attached to the opposite side of the arm 23 from the head slider 21.
- the voice coil 25 is clamped by a magnet (not shown) provided on the housing 20.
- a voice coil motor 26 is constituted by the voice coil 25 and the magnet.
- a predetermined current is supplied to the voice coil 25.
- the arm 23 swings around the vertical axis 24 by the action of electromagnetic force generated by the current flowing through the voice coil 25 and the magnetic field of the magnet.
- the suspension 22 and the head slider 21 also swing in the direction of the arrow AR1.
- the head slider 21 reciprocates on the front and back surfaces of the information recording medium 10 in the radial direction of the information recording medium 10.
- a magnetic head (not shown) provided on the head slider 21 performs a seek operation.
- the head slider 21 While the seek operation is performed, the head slider 21 receives a levitation force due to the air flow generated as the information recording medium 10 rotates. Due to the balance between the levitation force and the elastic force (pressing force) of the suspension 22, the head slider 21 travels with a constant flying height with respect to the surface of the information recording medium 10. By the traveling, the magnetic head provided on the head slider 21 can record and reproduce information (data) on a predetermined track in the information recording medium 10.
- the information recording apparatus 30 on which the glass substrate 1 is mounted as a part of the members constituting the information recording medium 10 is configured as described above.
- FIG. 2 is a plan view showing glass substrate 1 manufactured by the method for manufacturing a glass substrate for information recording medium according to the present embodiment.
- 3 is a cross-sectional view taken along the line III-III in FIG.
- the glass substrate 1 (glass substrate for information recording medium) used as a part of the information recording medium 10 (see FIGS. 4 and 5) has a main surface 2, a main surface 3, It has an inner peripheral end face 4 that defines the hole 5 and an outer peripheral end face 6 and is formed in a disk shape as a whole.
- the hole 5 is provided so as to penetrate from one main surface 2 toward the other main surface 3.
- the inner peripheral end surface 4 includes a straight portion 4a and a chamfered portion 4b.
- the chamfered portion 4b includes an inner peripheral end chamfer portion formed between one main surface 2 and the straight portion 4a, and an inner peripheral end chamber formed between the other main surface 3 and the straight portion 4a. Including the fur part.
- the outer peripheral end surface 6 includes a straight portion 6a and a chamfered portion 6b.
- the chamfered portion 6b includes an outer peripheral end chamfer portion formed between one main surface 2 and the straight portion 6a, and an outer peripheral end chamfer portion formed between the other main surface 3 and the straight portion 6a. Including.
- the glass substrate 1G has a size of 0.8 inch, 1 inch, 1.8 inch, 2.5 inch or 3.5 inch, for example.
- the glass substrate 1G has thicknesses of, for example, 0.3 mm, 0.65 mm, 0.8 mm, 1 mm, 2 mm, and 2.2 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.
- the glass composition of the glass substrate 1G is not particularly limited as long as it can be chemically strengthened by ion exchange.
- soda lime glass mainly composed of SiO 2 , Na 2 O and CaO
- aluminosilicate glass mainly composed of SiO 2 , Al 2 O 3 and R 2 O
- R K, Na, Li
- R ′ Mg, Ca, Sr, Ba
- FIG. 4 is a plan view showing an information recording medium 10 provided with a glass substrate 1 as an information recording medium.
- FIG. 5 is a cross-sectional view taken along the line VV in FIG.
- the information recording medium 10 includes a glass substrate 1, a compressive stress layer 12, and a magnetic recording layer 14.
- the compressive stress layer 12 is formed so as to cover the main surfaces 2 and 3, the inner peripheral end face 4, and the outer peripheral end face 6 of the glass substrate 1.
- the magnetic recording layer 14 is formed so as to cover a predetermined region on the main surfaces 2 and 3 of the compressive stress layer 12.
- the magnetic recording layer 14 is formed on both the compressive stress layer 12 formed on the main surface 2 and the compressive stress layer 12 formed on the main surface 3 (both sides). Is formed.
- the magnetic recording layer 14 may be provided only on the compression stress layer 12 (one side) formed on the main surface 2, or on the compression stress layer 12 (one side) formed on the main surface 3. It may be provided.
- the magnetic recording layer 14 is formed by spin-coating a thermosetting resin in which magnetic particles are dispersed on the compressive stress layer 12 on the main surfaces 2 and 3 of the glass substrate 1 (spin coating method).
- the magnetic recording layer 14 may be formed by a sputtering method or an electroless plating method performed on the compressive stress layer 12 on the main surfaces 2 and 3 of the glass substrate 1.
- the thickness of the magnetic recording layer 14 is about 0.3 ⁇ m to 1.2 ⁇ m for the spin coating method, about 0.04 ⁇ m to 0.08 ⁇ m for the sputtering method, and about 0.05 ⁇ m to about the electroless plating method. 0.1 ⁇ m. From the viewpoint of thinning and high density, the magnetic recording layer 14 is preferably formed by sputtering or electroless plating.
- a Co-based alloy or the like containing Ni or Cr as a main component is added for the purpose of adjusting the residual magnetic flux density. Is preferably used.
- Fe—Pt magnetic materials have been used as magnetic layer materials suitable for heat-assisted recording.
- the surface of the magnetic recording layer 14 may be thinly coated with a lubricant.
- a lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a solvent such as Freon.
- the magnetic recording layer 14 may be provided with a base layer or a protective layer as necessary.
- the underlayer in the information recording medium 10 is selected according to the type of 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.
- the underlayer provided on the magnetic recording layer 14 is not limited to a single layer, and may have a multilayer structure in which the same or different layers are stacked.
- 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 for preventing wear and corrosion of the magnetic recording layer 14 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 together with the underlayer and the magnetic film. These protective layers may be a single layer, or may have a multilayer structure composed of the same or different layers.
- Another protective layer may be formed on the protective layer or instead of the protective layer.
- tetraalkoxylane is diluted with an alcohol-based solvent on a Cr layer, and then colloidal silica fine particles are dispersed and applied, followed by baking to form a silicon oxide (SiO 2 ) layer. It may be formed.
- the glass substrate 1 has a thickness of, for example, 0.3 mm, 0.65 mm, 0.8 mm, 1 mm, 2 mm, and 2.2 mm is exemplified. It is preferable to have a thickness of When the thickness of the glass substrate is reduced and the fluttering amount of the glass substrate itself is increased (the fluttering amount when the thickness is 0.635 mm, for example, is twice the fluttering amount when the thickness is 0.8 mm).
- the above-described durability can be remarkably improved, and the flying characteristics of the magnetic head can be more reliably stabilized.
- FIG. 6 is a flowchart showing a method for manufacturing the glass substrate 1 and the information recording medium 10.
- step 10 a “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.
- 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.
- 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.
- a hole was formed in the center of the glass substrate using a cylindrical diamond drill to produce an annular glass substrate.
- 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.
- the inner peripheral end surface of the glass substrate was subjected to mirror polishing by brush polishing.
- a slurry containing general cerium oxide abrasive grains (average particle diameter ⁇ 2 ⁇ m) was used.
- 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.
- the outer peripheral end face of the glass substrate was subjected to mirror polishing by brush polishing.
- a slurry containing general cerium oxide abrasive grains was used as the abrasive grains.
- first polishing step 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.
- the main surface was polished by a double-side polishing apparatus having a planetary gear mechanism.
- abrasive general cerium oxide abrasive grains were used.
- a surface reinforcing layer was formed on the main surface of the glass substrate 1.
- chemical strengthening was performed by immersing the glass substrate 1 in a mixed solution of potassium nitrate (70%) and sodium nitrate (30%) heated to 300 ° C. for about 30 minutes.
- 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.
- the main surface polishing step was performed in the “second polishing step” of S20.
- 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.
- polishing was performed by a double-side polishing apparatus having a planetary gear mechanism.
- abrasive colloidal silica having an average particle diameter of about 20 nm was used to obtain a smooth surface.
- an adhesion layer made of a Cr alloy and a soft magnetic layer made of a CoFeZr alloy are formed on both main surfaces of the glass substrate 1.
- An information recording medium of a perpendicular magnetic recording system was manufactured by sequentially forming an orientation control underlayer made of Ru, a perpendicular magnetic recording layer made of a CoCrPt alloy, a C-based protective layer, and an F-based lubricating layer.
- 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.
- an FePt-based material may be used as a magnetic layer material suitable for heat-assisted recording.
- the “post-heat treatment step” of S23 is performed to complete the information recording medium.
- FIG. 7 is a schematic diagram illustrating a problem that occurs in the method for manufacturing a glass substrate.
- the HDD device when a larger impact than expected is applied, the HDD device may not operate.
- the glass substrate 1 (magnetic disk) in the HDD device is damaged in the event of an impact such as dropping.
- the broken glass substrate 1 was investigated, it turned out that the broken part has the high tendency for a part (streak-like crack) of the inner peripheral end surface 4 of the glass substrate 1 to start.
- the cause of the occurrence of streak-like scratches was as follows.
- the inner peripheral end face is finished to a mirror surface by using cerium oxide as an abrasive.
- cerium oxide in FIG. 7 is applied to the inner peripheral end surface 4 of the glass substrate 1 when the holding pad 100 is moved to the next step and / or when the polishing pad 110 is pressed during polishing. Ce) tends to pierce or react with the glass substrate 1 to be easily fused.
- the “cleaning before chemical strengthening” of S18 is performed before the “chemical strengthening step” of S19, and the inner peripheral end face 4 of the glass substrate 1 has ⁇ 0.1 ⁇ m or more. Cleaning is performed so that the amount of the cerium oxide residue is 3 pieces / mm 2 or less.
- FIG. 8 is a schematic diagram of a cleaning apparatus used for cleaning the glass substrate 1 before chemical strengthening
- FIG. 9 is an enlarged view of the cleaning apparatus used for cleaning the glass substrate 1 before chemical strengthening.
- a cleaning liquid W having a concentration of 3% acidic detergent is accumulated in a circulation tank 501, and a plurality of glass substrates 1 are immersed therein.
- the glass substrate 1 has a plurality of glass substrates 1 held in a horizontal direction by a substrate holding member 51 and held in a vertical direction at a predetermined interval.
- the substrate holding member 51 includes a frame member 55 that holds the outer peripheral end of the glass substrate 1 and a guide portion 53 that directly contacts the outer peripheral end of the frame member 55 and positions the glass substrate 1. .
- a vibrating bar 59 is inserted into the hole 5 of each glass substrate 1.
- the vibrating bar 59 is connected to a vibrating element 58 and a transmitter 50 that apply ultrasonic waves (US) of a predetermined frequency to the vibrating bar 59 to vibrate the vibrating bar 59.
- US ultrasonic waves
- the diameter of the vibrating bar 59 is preferably about 5 mm.
- the frequency applied to the vibrating bar 59 by the vibrating element 58 and the transmitter 50 may be 40 kHz to 60 kHz.
- Ultrasonic (US) cleaning was performed for about 5 minutes at a liquid temperature of the cleaning liquid W of 30 ° C.
- a brush (channel brush) 590 has a configuration in which a brush portion 592 is fixed to a base portion 591 and extends in the longitudinal direction.
- the cross-sectional shape of the base portion 591 is substantially square, and the length of one side (h1) is about 1.5 mm in this embodiment.
- the protruding length (h2) of the brush part 592 from the base part 591 is about 4 mm.
- Nylon fibers having a diameter of 0.2 mm were used for the brush bristles of the brush portion 592.
- brush hair made of vinyl chloride or pig hair may be used.
- the glass substrate 1 is cleaned with a brush 590 in contact with the inner peripheral end face 4.
- ultrasonic (US) cleaning was performed for about 5 minutes while rotating the vibrating rod 59A (in the direction of arrow R) and swinging up and down (in the direction of arrow Y). As a result, it is possible to remove the cerium oxide that is firmly adhered to the inner peripheral end face 4.
- the glass substrate 1 is rotated at 15 rpm and the vibrating rod 59A is rotated at 985 rpm so as to be mutually reverse.
- the relative rotation speed between the inner peripheral end face 4 and the brush 590 is preferably about 1000 rpm or more.
- the brush 590 of the vibrating bar 59A was pressed about 2 mm in one direction on the inner peripheral end face 4, and ultrasonic waves (US) were performed while the vibrating bar 59A was swung up and down at a speed of 400 mm / min.
- the shape and attachment method of the brush 590 are not limited to this embodiment.
- the glass substrate 1 was immersed in a circulation tank for 3 minutes using a cleaning liquid having an HF concentration of 0.2% and a liquid temperature of 30 ° C. As a result, the reacted cerium oxide is dissolved and removed together with the glass substrate 1 on all the main surfaces 2 and 3 including the inner peripheral end face 4. If the liquid temperature and time are fixed due to a chemical reaction, if the concentration is low, a sufficient effect cannot be obtained. On the contrary, if the concentration is high, the surface of the glass substrate 1 is rough and the dimensions change, such being undesirable. Therefore, the HF concentration is preferably 0.1% to 0.3%.
- FIG. 13 is a diagram showing the results of drop impact tests of Examples 1 to 3 and Comparative Examples 1 to 3.
- Example 1 In Example 1, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As cleaning before chemical strengthening (S18), the above-described cleaning steps 2 to 6 were performed.
- Example 2 In Example 2, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As the cleaning before chemical strengthening (S18), the cleaning steps 1 to 6 were performed.
- Example 3 In Example 3, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As the cleaning before chemical strengthening (S18), the cleaning steps 1 to 6 were performed. However, the conditions were changed as shown below. Washing step 1 was carried out in twice the washing time of 10 minutes. A refreshing process using a brush was performed every time before the cleaning process 2 was performed. That is, since the cerium oxide removed also adheres to the brush as the number of times of use, a process of preparing a substrate that has been completed up to the final cleaning step in advance and cleaning it as a dummy substrate to remove the cerium oxide adhering to the brush Added. The washing time of washing step 2 was doubled for 10 minutes.
- Comparative Example 1 In Comparative Example 1, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As cleaning before chemical strengthening (S18), cleaning steps 1 to 3 were not performed, and only cleaning steps 4 to 6 were performed.
- Comparative Example 2 In Comparative Example 2, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As cleaning before chemical strengthening (S18), only cleaning steps 3 to 6 were performed without performing cleaning steps 1 and 2.
- Comparative Example 3 In Comparative Example 3, a glass substrate and an information recording medium were manufactured based on the manufacturing flow shown in FIG. As cleaning before chemical strengthening (S18), only cleaning steps 3 to 6 were performed without performing cleaning steps 1 and 2. However, three tanks of HF immersion cleaning in the cleaning step 3 were provided, and the cleaning was performed 3 times ⁇ 3 times. In this case, cerium oxide is further removed by the etching effect of HF, but there is a possibility that the cleaning tank equipment becomes large and the roughness of the end face surface reaches the upper limit of the standard value.
- the inner peripheral end face 4 of the extracted glass substrate is divided into several parts so that it can be observed with a scanning electron microscope (SEM), and observation of deposits with an SEM and an energy dispersive X-ray analyzer (EDX: Energy Dispersive X) -ray spectrocopy) was performed, and the number of cerium oxides having a diameter of 0.1 ⁇ m or more present on the inner peripheral end face 4 was determined. Then, the amount of cerium oxide residue (number) per unit area (1 square millimeter) was determined by dividing by the area of the inner peripheral end face 4.
- SEM scanning electron microscope
- EDX Energy Dispersive X-ray analyzer
- the amount (number) of residues per unit area of cerium oxide before the chemical strengthening step is 3 / mm 2 in Example 1, 2.6 / mm 2 in Example 2 , Example 3 was 1.9 pieces / mm 2 .
- Comparative Example 1 4.5 / mm 2, Comparative Example 2, 3.8 / mm 2, Comparative Example 3 was 3.3 pieces / mm 2.
- the magnetic disks produced in Examples 1 to 3 and Comparative Examples 1 to 3 were mounted on a 5000 rpm HDD device, and a drop impact test was performed.
- the tester was performed by dropping the HDD device attached with the magnetic disk of each example and each comparative example from a certain height using a commercially available drop impact tester. In the test, after dropping the HDD device from a height of 1 m, the HDD device was disassembled and the presence or absence of cracking of the magnetic disk was visually confirmed.
- FIG. 13 shows the evaluation results of the 1000 magnetic disk HDD devices produced in each example and each comparative example. Determination of crack occurrence rate (quality) after the drop test is evaluated as “A” when the cracks generated are 1 or less, “B” when 2-5, and 6-10. The case of “C” and 11 or more sheets is evaluated as “F”.
- A is a satisfactory level for actual use
- B is a level that is sufficiently usable
- C is an unstable level for actual use
- F is for practical use. Is an unsuitable level.
- the evaluation result is proportional to the amount (number) of residues per unit area of cerium oxide before the chemical strengthening step, and the amount of residues (number) per unit area of cerium oxide is 1.9. pieces / mm 2 of example 3 is the most evaluation result is good, an evaluation "a”, then the second embodiment of the residual amount (number) is 2.6 / mm 2 is rated "B”, the residue Example 3 having an amount (number) of 3 / mm 2 was also evaluated as “B”.
- Comparative Example 1 of residual amount (number) is 4.5 pieces / mm 2
- Comparative Example 2 3.8 pieces / mm 2 are both rated “F” residual amount (number) of 3 Comparative example 3 with 3 pieces / mm 2 was evaluated as “C”.
- cleaning of the glass substrate 1 implemented before the process of chemically strengthening the surface of the glass substrate 1 is the glass substrate 1.
- Cleaning is performed on the inner peripheral end face 4 so that the amount of cerium oxide residue of ⁇ 0.1 ⁇ m or more is 3 pieces / mm 2 or less.
- polishing steps S20, S17
- chemical strengthening step S19
- cerium oxide is removed by turning around the end surface of the polishing pad during polishing, and scratches on the surface of the inner peripheral end surface are removed. Occurrence is assumed. As a result, it can be expected that the stress is released and the glass substrate is weakened by a drop impact. Therefore, by adopting the method of manufacturing the glass substrate for information recording medium of the present embodiment, the present embodiment is more effective. The effect of can be obtained.
- the thinner glass substrate 1 is weak against the same impact.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
Description
(情報記録装置30)
図1を参照して、情報記録装置30について説明する。図1は、情報記録装置30を示す斜視図である。情報記録装置30は、実施の形態における情報記録媒体用ガラス基板(以下、単にガラス基板ともいう)の製造方法によって製造されたガラス基板1を、情報記録媒体10として備える。
図2は、本実施の形態に基づく情報記録媒体用ガラス基板の製造方法によって製造されるガラス基板1を示す平面図である。図3は、図2中のIII-III線に沿った矢視断面図である。
図4は、情報記録媒体としてガラス基板1を備えた情報記録媒体10を示す平面図である。図5は、図4中のV-V線に沿った矢視断面図である。
次に、図6を参照して、本実施の形態に係るガラス基板1および情報記録媒体10の製造方法を説明する。図6は、ガラス基板1および情報記録媒体10の製造方法を示すフロー図である。
ここで、発明者らが知見したガラス基板の製造方法の課題について、図7を参照して説明する。図7は、ガラス基板の製造方法において生じる課題を示す模式図である。
この洗浄装置500は、循環槽501内に、酸性洗剤の濃度が3%の洗浄液Wが蓄積され、複数枚のガラス基板1が浸漬されている。
次に、図10から図12を参照して、振動棒59に代わり、振動棒59Aを用いてUS洗浄を行なう。この振動棒59Aの基本的構成は、上記した振動棒59と同じであり、相違点は、図10に示すように、筒状の振動棒59の外周面に、螺旋状にブラシ590が巻きつけられている。上下に隣接するブラシ590の配置ピッチP1は、本実施の形態では、4mmに設定している。配置ピッチP1が細かすぎると洗浄液Wの置換効率が悪く、配置ピッチP1が大きすぎると洗浄液Wの洗浄能力が低下する。よって、ブラシ590の配置ピッチP1は、適宜変更することが望ましい。
次に、循環槽において、HF濃度0.2%、液温30℃の洗浄液を用いて、ガラス基板1を3分間浸漬させた。これにより内周端面4を含む全ての主表面2,3において、反応している酸化セリウムをガラス基板1とともに溶解、除去する。化学反応の為、液温、時間が固定の場合、濃度が薄いと十分な効果がえられず、逆に濃い場合はガラス基板1の表面が粗れて寸法が変化するので好ましくない。よって、HF濃度は、0.1%~0.3%が好ましい。
次に、酸洗剤濃度3%、液温30℃の洗浄液を用いて、槽底に振動板がレイアウトされた浸漬式のUS洗浄(80KHz)を5分実施し、ガラス基板全面の洗浄を行なった。
その後、純水、1way槽を用いて、槽底に振動板がレイアウトされた浸漬式のUS洗浄(80KHz)を5分実施し、ガラス基板1全面の最終リンスを行なった。
最後にIPA(イソプロピルアルコール)循環槽にガラス基板1を浸漬し、その後IPAベーパー槽にてガラス基板1乾燥させた。
以下、図13を参照して、本実施の形態における各実施例について説明する。図13は、実施例1から3、比較例1から3の落下衝撃試験の結果を示す図である。
実施例1は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、上記洗浄工程2から6を実施した。
実施例2は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、上記洗浄工程1から6を実施した。
実施例3は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、上記洗浄工程1から6を実施した。ただし、以下に示すように条件を変更した。洗浄工程1は、洗浄時間を2倍の10分で実施した。洗浄工程2の洗浄前に毎回ブラシを用いたレフレッシュ工程を実施した。すなわち、使用回数につれてブラシにも除去した酸化セリウムが付着する為に、予め最終洗浄工程まで完了した基板を準備し、それをダミー基板として洗浄することで、ブラシに付着した酸化セリウムを除去する工程を追加した。洗浄工程2の洗浄時間を2倍の10分で実施した。
比較例1は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、洗浄工程1~3は実施せずに、洗浄工程4~6のみを実施した。
比較例2は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、洗浄工程1~2は実施せずに、洗浄工程3~6のみを実施した。
比較例3は、図6に示す製造フローに基づきガラス基板および情報記録媒体を製造した。化学強化前洗浄(S18)としては、洗浄工程1~2は実施せずに、洗浄工程3~6のみを実施した。ただし、洗浄工程3のHF浸漬洗浄を3槽設けて、各3分×3回の洗浄として実施した。この場合、HFのエッチング効果により酸化セリウムはさらに除去されるが、洗浄槽設備が大きくなることと、端面表面の粗さが規格値上限にまで達してしまうおそれがある。
実施例1、2、3、比較例1、2、3で作製したガラス基板において、S18後(化学強化工程(S19)前)のガラス基板に対して、内周端面4に存在する酸化セリウムの評価を下記のように行なった。
Claims (5)
- 情報記録媒体用ガラス基板の製造方法であって、
一方の主表面、他方の主表面、孔を規定する内周端面、および外周端面を有し、全体として円盤状のガラス基板を成形する工程と、
前記内周端面に対して、酸化セリウムによる内端研磨を行なう工程と、
前記ガラス基板の洗浄を行なう工程と、
前記ガラス基板の洗浄を行なった後に、前記ガラス基板の表面を化学強化する工程と、を備え、
前記ガラス基板の洗浄を行なう工程は、前記ガラス基板の前記内周端面において、φ0.1μm以上の酸化セリウムの残渣量が3個/mm2以下となるように洗浄を行なう工程を含む、情報記録媒体用ガラス基板の製造方法。 - 前記ガラス基材の洗浄を行なう工程は、
前記ガラス基板を洗浄液中に浸漬させた状態で、前記孔に振動棒を挿入し、前記振動棒に超音波を付与して前記振動棒を振動させて、前記ガラス基板の洗浄を行なう、請求項1に記載の情報記録媒体用ガラス基板の製造方法。 - 前記振動棒にブラシを装着し、前記内周端面に前記ブラシを当接させた状態で、前記ガラス基板の洗浄を行なう、請求項2に記載の情報記録媒体用ガラス基板の製造方法。
- 前記化学強化を行なった後に、少なくとも1つ以上の精密研磨を行なう工程を含む、請求項1または3のいずれか1項に記載の情報記録媒体用ガラス基板の製造方法。
- 前記ガラス基板の厚みが、0.65mm以下である、請求項1または4のいずれか1項に記載の情報記録媒体用ガラス基板の製造方法。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SG11201601610QA SG11201601610QA (en) | 2013-09-17 | 2014-08-26 | Method for manufacturing glass substrate for information recording medium |
CN201480047838.4A CN105493183A (zh) | 2013-09-17 | 2014-08-26 | 信息记录介质用玻璃基板的制造方法 |
JP2015537618A JPWO2015041011A1 (ja) | 2013-09-17 | 2014-08-26 | 円盤状ガラス基板の製造方法、円盤状ガラス基板、情報記録媒体用ガラス基板、および、情報記録媒体 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013-191767 | 2013-09-17 | ||
JP2013191767 | 2013-09-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015041011A1 true WO2015041011A1 (ja) | 2015-03-26 |
Family
ID=52688666
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2014/072303 WO2015041011A1 (ja) | 2013-09-17 | 2014-08-26 | 情報記録媒体用ガラス基板の製造方法 |
Country Status (4)
Country | Link |
---|---|
JP (1) | JPWO2015041011A1 (ja) |
CN (1) | CN105493183A (ja) |
SG (1) | SG11201601610QA (ja) |
WO (1) | WO2015041011A1 (ja) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03245388A (ja) * | 1990-02-22 | 1991-10-31 | Supiide Fuamu Clean Syst Kk | ディスク基板用洗浄装置 |
JP2004059419A (ja) * | 2002-05-31 | 2004-02-26 | Nippon Sheet Glass Co Ltd | ガラス基材の製造方法及びその製造方法で得られたガラス基材 |
JP2004273623A (ja) * | 2003-03-06 | 2004-09-30 | Shibaura Mechatronics Corp | ブラシ洗浄装置及びブラシ洗浄方法 |
WO2012093516A1 (ja) * | 2011-01-07 | 2012-07-12 | 旭硝子株式会社 | 情報記録媒体用ガラス基板、その製造方法および磁気記録媒体 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3706617B2 (ja) * | 2003-04-22 | 2005-10-12 | 島田理化工業株式会社 | 被洗浄物の洗浄方法 |
JP4481811B2 (ja) * | 2004-12-27 | 2010-06-16 | 富士通株式会社 | 洗浄装置及び洗浄方法 |
JP5152357B2 (ja) * | 2011-03-07 | 2013-02-27 | 旭硝子株式会社 | 磁気記録媒体用ガラス基板の製造方法 |
JP5067498B1 (ja) * | 2011-10-13 | 2012-11-07 | 旭硝子株式会社 | 磁気記録媒体用ガラス基板及び磁気記録媒体 |
-
2014
- 2014-08-26 SG SG11201601610QA patent/SG11201601610QA/en unknown
- 2014-08-26 CN CN201480047838.4A patent/CN105493183A/zh active Pending
- 2014-08-26 JP JP2015537618A patent/JPWO2015041011A1/ja active Pending
- 2014-08-26 WO PCT/JP2014/072303 patent/WO2015041011A1/ja active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03245388A (ja) * | 1990-02-22 | 1991-10-31 | Supiide Fuamu Clean Syst Kk | ディスク基板用洗浄装置 |
JP2004059419A (ja) * | 2002-05-31 | 2004-02-26 | Nippon Sheet Glass Co Ltd | ガラス基材の製造方法及びその製造方法で得られたガラス基材 |
JP2004273623A (ja) * | 2003-03-06 | 2004-09-30 | Shibaura Mechatronics Corp | ブラシ洗浄装置及びブラシ洗浄方法 |
WO2012093516A1 (ja) * | 2011-01-07 | 2012-07-12 | 旭硝子株式会社 | 情報記録媒体用ガラス基板、その製造方法および磁気記録媒体 |
Also Published As
Publication number | Publication date |
---|---|
SG11201601610QA (en) | 2016-04-28 |
CN105493183A (zh) | 2016-04-13 |
JPWO2015041011A1 (ja) | 2017-03-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2007294073A (ja) | 磁気ディスク用ガラス基板の製造方法及び磁気ディスクの製造方法 | |
JP6105488B2 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP2004335081A (ja) | 磁気ディスク用ガラス基板の洗浄方法及び磁気ディスク用ガラス基板の製造方法並びに磁気ディスクの製造方法 | |
JP4860580B2 (ja) | 磁気ディスク用基板及び磁気ディスク | |
JP6423935B2 (ja) | 情報記録媒体用ガラス基板の製造方法および研磨用ブラシ | |
JP5978394B2 (ja) | 板ガラスの製造方法、情報記録媒体用ガラス基板の製造方法および情報記録媒体の製造方法 | |
WO2014148421A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
WO2015041011A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP5067498B1 (ja) | 磁気記録媒体用ガラス基板及び磁気記録媒体 | |
WO2013099656A1 (ja) | 情報記録媒体用ガラス基板およびその製造方法 | |
JP5392075B2 (ja) | 情報記録装置 | |
JP5897959B2 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP5886108B2 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP5303741B1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
WO2014045653A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP6196976B2 (ja) | 情報記録媒体用ガラス基板の製造方法、情報記録媒体の製造方法、および、情報記録媒体用ガラス基板 | |
JPWO2013099584A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP6021911B2 (ja) | 情報記録媒体用ガラス基板および情報記録媒体用ガラス基板の製造方法 | |
WO2014103982A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
JP2013206501A (ja) | Hdd用ガラス基板の製造方法 | |
JP2011086371A (ja) | 磁気ディスク用ガラス基板の製造方法 | |
WO2013099585A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
WO2013047288A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
WO2013047287A1 (ja) | 情報記録媒体用ガラス基板の製造方法 | |
WO2014156795A1 (ja) | 情報記録媒体用ガラス基板およびその製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 201480047838.4 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 14845660 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2015537618 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 14845660 Country of ref document: EP Kind code of ref document: A1 |