WO2014002702A1 - Manufacturing method for information recording medium, and board stripping jig - Google Patents

Abstract

Provided is a manufacturing method for an information recording medium which is capable of shortening discharge time of a fluid when stripping a glass substrate from a polishing platen after a polishing step. A manufacturing method for an information recording medium that is provided with a glass substrate (1) having a main surface, and a magnetic thin-film layer formed upon the main surface of the glass substrate (1), is provided with steps for: pressing, upon the polishing surface of the platen, the glass substrate (1) so as to polish the main surface thereof; and stripping the glass substrate (1) from the polishing surface using a board stripping jig. The board stripping jig has a nozzle (21) which discharges compressed air (A), and a contact surface (27) which comes into tactile contact with the glass substrate (1) which moves in the surface direction of the polishing surface by way of the compressed air (A), and includes a positioning unit (26) which defines a position for the glass substrate (1), and a board receiving unit (25) which receives and holds the glass substrate (1) which floats from the polishing surface by way of the compressed air (A).

Description

Information recording medium manufacturing method and substrate peeling jig

The present invention relates to an information recording medium manufacturing method and a substrate peeling jig, and in particular, an information recording medium manufacturing method including a glass substrate and a substrate peeling jig used for peeling a polished glass substrate from a surface plate. And about.

An information recording medium such as a magnetic disk is mounted as a hard disk on a computer or the like. An information recording medium is manufactured by forming a magnetic thin film layer including a recording layer using properties such as magnetism, light, or magnetomagnetism on the surface of a substrate. As the recording layer is magnetized by the magnetic head, predetermined information is recorded on the information recording medium.

The recording density of information recording media is improving year by year. Accordingly, high quality is required for the quality of substrates used for information recording media. Conventionally, an aluminum substrate has been used as a substrate for an information recording medium. However, as the recording density is improved, it is gradually being replaced by a glass substrate that is superior in smoothness and strength of the substrate surface as compared with an aluminum substrate.

The method for producing a glass substrate for an information recording medium has a polishing step for ensuring high surface shape accuracy. In order to achieve highly accurate shape quality of the glass substrate, two or more stages of polishing processes in which slurry and polishing pads having different processing capabilities are effectively combined are applied.

Conventionally, in a polishing process of a glass substrate, a double-side polishing apparatus is used in which both surfaces of a glass substrate are sandwiched between polishing pads and polished while supplying a polishing slurry. After completion of the polishing process using the double-side polishing apparatus, the glass substrate is stuck to the polishing pad. As a technique for taking out a glass substrate attached to a polishing pad from a double-side polishing apparatus without damaging the substrate surface, an adsorption support tool that adsorbs the glass substrate with a negative pressure has been conventionally proposed (for example, a special technique). No. 2007-216311 (Patent Document 1)).

The polishing slurry remaining on the polished glass substrate includes used or unused polishing abrasive grains and polishing scraps generated by polishing. For this reason, when the substrate surface is adsorbed by the adsorption support tool, the abrasive grains or the polishing debris adhere to the place where the adsorption support tool on the main surface of the glass substrate is in contact. When the adsorption time becomes long, the adsorbed portion dries early and the adhered matter sticks, and there is a problem that the surface quality of the main surface of the glass substrate is lowered. In response to this problem, a substrate peeling jig using compressed air, in which compressed air is jetted from a nozzle to float the glass substrate, and the glass substrate is supported by a substrate receiving portion composed of a cylindrical brush, sponge, etc. Has been proposed (for example, see Japanese Patent Application Laid-Open No. 2011-204321 (Patent Document 2)).

JP 2007-216311 A JP 2011-204321 A

In the substrate peeling jig described in Japanese Patent Application Laid-Open No. 2011-204321 (Patent Document 2), when compressed air is jetted, the glass substrate is pushed by the compressed air and moves horizontally on the surface plate, and is moved to the substrate receiving portion. On the other hand, the glass substrate was displaced, and as a result, the floating glass substrate was caught on the substrate receiving portion. When this catching occurs, the compressed air ejection time until the glass substrate is held by the substrate receiving portion becomes longer, the substrate surface dries, and the abrasive grains or polishing debris present on the glass substrate become convex on the substrate surface. In the worse case, there was a problem that the glass substrate itself could not be collected.

Deposits on the surface of the substrate become protrusions on the main surface of an information recording medium made from a glass substrate, causing problems such as errors or inability to read when passing through the magnetic head, and adversely affecting the flying characteristics of the magnetic head. Effect. For this reason, when peeling a glass substrate, the glass substrate was floated smoothly and the means which can hold | maintain a glass substrate to a board | substrate receiving part in a short time became a subject.

The present invention has been made in view of the above problems, and its main object is to provide a method for manufacturing an information recording medium that can shorten the fluid discharge time when the glass substrate after the polishing process is peeled off from the polishing surface plate. Is to provide. Another object of the present invention is to provide a substrate peeling jig that can be suitably used in the method for producing the information recording medium.

A method for manufacturing an information recording medium according to the present invention is a method for manufacturing an information recording medium, comprising: a glass substrate having a main surface; and a magnetic thin film layer formed on the main surface of the glass substrate. A step of pressing the glass substrate against the polishing surface to polish the main surface, and a step of peeling the glass substrate from the polishing surface using a substrate peeling jig. The substrate peeling jig has a nozzle that discharges fluid, a contact surface that comes into contact with the glass substrate that moves in the direction of the polishing surface by the fluid, a positioning portion that determines the position of the glass substrate, and the fluid is lifted from the polishing surface by the fluid A substrate receiving portion for receiving and holding the glass substrate.

Preferably, in the above method, the contact surface of the positioning portion is inclined toward the side closer to the substrate receiving portion as the distance from the polishing surface increases with respect to the normal direction of the polishing surface.

Preferably, in the above method, the contact surface of the positioning portion is inclined toward the side away from the substrate receiving portion as it is away from the polishing surface with respect to the normal direction of the polishing surface.

Preferably, in the above method, the contact surface of the positioning portion is formed in a shape in which the end on the polishing surface side is bent toward the substrate receiving portion.

Preferably, in the above method, the substrate peeling jig includes a shaft portion, the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion, and the substrate peeling jig has an end portion on the polishing surface side of the shaft portion. An elastic body is further included.

Preferably, in the above method, the positioning portion surrounds three sides of the glass substrate.
Preferably in the above method, the fluid is high pressure water.

Preferably, in the above method, the fluid includes compressed air and water.
Preferably, in the above method, the substrate peeling jig includes a temporary positioning portion disposed at a position facing the positioning portion via the substrate receiving portion, and before the glass substrate is peeled from the polishing surface, the outer peripheral end surface of the glass substrate. The position of the substrate peeling jig is defined by arranging the temporary positioning portions so as to face each other.

Preferably, in the above method, the substrate peeling jig includes a shaft portion, the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion, and the substrate peeling jig is provided at an end of the shaft portion on the polishing surface side. It further includes a light projecting unit that emits light.

Preferably, in the above method, the substrate peeling jig includes a shaft portion, the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion, and the substrate receiving portion faces the end portion of the shaft portion on the polishing surface side. Taper.

A substrate peeling jig according to the present invention is a substrate peeling jig used for peeling a glass substrate pressed on a polishing surface of a surface plate and polished on a main surface from the polishing surface, and a nozzle for discharging a fluid. And a contact portion that contacts the glass substrate that moves in the surface direction of the polishing surface by the fluid, a positioning portion that determines the position of the glass substrate, and a substrate receiving portion that receives and holds the glass substrate that is lifted from the polishing surface by the fluid ,including.

According to the method for producing an information recording medium of the present invention, the fluid discharge time when the glass substrate is peeled from the polishing platen after the polishing step can be shortened, so that the quality of the glass substrate can be improved by suppressing the drying of the glass substrate. Productivity can be improved by shortening the time required for manufacturing the substrate.

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 schematic diagram which shows the outline of a structure of a board | substrate peeling jig | tool. FIG. 3 is a schematic diagram showing a first step during the peeling operation of the glass substrate of the first embodiment. 6 is a schematic diagram showing a second step during the peeling operation of the glass substrate of Embodiment 1. FIG. FIG. 6 is a schematic diagram showing a third step during the peeling operation of the glass substrate of the first embodiment. It is a plane schematic diagram which shows an example of a positioning part. It is a plane schematic diagram which shows the modification of a positioning part. FIG. 10 is a schematic diagram showing a first step during the peeling operation of the glass substrate of the second embodiment. FIG. 10 is a schematic diagram showing a second step during the peeling operation of the glass substrate of the second embodiment. FIG. 10 is a schematic diagram showing a third step during the peeling operation of the glass substrate according to the second embodiment. FIG. 10 is a schematic diagram showing a first step during the peeling operation of the glass substrate according to the third embodiment. FIG. 10 is a schematic diagram showing a second step during the peeling operation of the glass substrate according to the third embodiment. 10 is a schematic diagram showing a third step during the peeling operation of the glass substrate of Embodiment 3. FIG. FIG. 10 is a schematic diagram showing a first step during the peeling operation of the glass substrate according to the fourth embodiment. FIG. 10 is a schematic diagram showing a second step during the peeling operation of the glass substrate according to the fourth embodiment. FIG. 10 is a schematic diagram showing a third step during the peeling operation of the glass substrate according to the fourth embodiment. FIG. 10 is a schematic diagram showing a first step during the peeling operation of the glass substrate of the fifth embodiment. FIG. 10 is a schematic diagram showing a second step during the peeling operation of the glass substrate according to the fifth embodiment. FIG. 10 is a schematic diagram showing a third step during the peeling operation of the glass substrate according to the fifth embodiment. FIG. 10 is a schematic diagram showing an outline of a configuration of a substrate peeling jig according to a sixth embodiment. It is a schematic diagram which shows the 1st process in the peeling operation | movement of the glass substrate of Embodiment 7. FIG. 11 is a schematic diagram showing a second step during the peeling operation of the glass substrate according to the seventh embodiment. FIG. 11 is a schematic diagram showing a third step during the peeling operation of the glass substrate according to the seventh embodiment. FIG. 20 is a schematic diagram showing an outline of a configuration of a substrate peeling jig according to an eighth embodiment. It is a schematic diagram which shows the 1st process in the peeling operation | movement of the glass substrate of Embodiment 9. It is a schematic diagram which shows the 2nd process in peeling operation | movement of the glass substrate of Embodiment 9. It is a schematic diagram which shows the 3rd process in peeling operation | movement of the glass substrate of Embodiment 9. It is a schematic diagram which shows the 1st process in the peeling operation | movement of the glass substrate of Embodiment 10. FIG. FIG. 32 is an enlarged schematic diagram of a region XXXII shown in FIG. 31. It is a schematic diagram which shows the 2nd process in peeling operation | movement of the glass substrate of Embodiment 10. FIG. It is a schematic diagram which shows the 3rd process in peeling operation | movement of the glass substrate of Embodiment 10. FIG. It is a schematic diagram which shows the 1st process in the peeling operation | movement of the glass substrate of Embodiment 11. It is a schematic diagram which shows the 2nd process in peeling operation | movement of the glass substrate of Embodiment 11. It is a schematic diagram which shows the 3rd process in peeling operation | movement of the glass substrate of Embodiment 11.

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 1 and magnetic disk 10]
With reference to FIG. 1 and FIG. 2, the glass substrate 1 obtained by the manufacturing method of the glass substrate for information recording media based on this Embodiment and the magnetic disc 10 provided with the glass substrate 1 are demonstrated first. FIG. 1 is a perspective view showing a glass substrate 1 used for a magnetic disk 10 (see FIG. 2). FIG. 2 is a perspective view showing a magnetic disk 10 provided with a glass substrate 1 as an information recording medium.

As shown in FIG. 1, a glass substrate 1 (glass substrate for information recording medium) used for a magnetic disk 10 has an annular disk shape with a hole 1H formed in the center. The circular disk-shaped glass substrate 1 has a front main surface 1A, a back main surface 1B, an inner peripheral end surface 1C, and an outer peripheral end surface 1D.

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

As shown in FIG. 2, in the magnetic disk 10, a magnetic film is formed on the front main surface 1A of the glass substrate 1 to form a magnetic thin film layer 2 including a magnetic recording layer. In FIG. 2, the magnetic thin film layer 2 is formed only on the front main surface 1A, but the magnetic thin film layer 2 may also be formed on the back main surface 1B.

The magnetic thin film layer 2 is formed by spin-coating a thermosetting resin in which magnetic particles are dispersed on the front main surface 1A of the glass substrate 1 (spin coating method). The magnetic thin film layer 2 may be formed on the front main surface 1A of the glass substrate 1 by a sputtering method, an electroless plating method, or the like.

The film thickness of the magnetic thin film layer 2 formed on the front main surface 1A of the glass substrate 1 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 electroless plating, 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 2 is preferably formed by sputtering or electroless plating.

The magnetic material used for the magnetic thin film layer 2 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 2 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, if necessary, an underlayer or a protective layer may be provided. The underlayer in the magnetic disk 10 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.

Also, 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 for preventing wear and corrosion of the magnetic thin film layer 2 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, in place of the protective layer, tetraalkoxysilane 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.

[Glass substrate manufacturing method]
Next, a method for manufacturing a glass substrate for information recording medium (hereinafter simply referred to as a glass substrate) in the present embodiment will be described with reference to the flowchart shown in FIG. FIG. 3 is a flowchart showing a method for manufacturing the glass substrate 1 in the embodiment.

The glass substrate manufacturing method in the present embodiment includes a glass blank material preparation step (step S10), a glass substrate formation / grinding step (step S20), a polishing step (step S30), a chemical strengthening step (step S40), and a cleaning. The process (step S50) is provided. The magnetic thin film forming step (step S60) may be performed on the glass substrate (corresponding to the glass substrate 1 in FIG. 1) obtained through the chemical strengthening treatment step (step S40). The magnetic disk 10 as an information recording medium is obtained by the magnetic thin film forming step (step S60).

Hereinafter, details of each of these steps S10 to S60 will be described in order. In the following, simple cleaning appropriately performed between each of steps S10 to S60 is not described.

(Glass blank material preparation process)
In the glass blank material preparation step (step S10), the glass material constituting the glass substrate is melted (step S11). For example, general aluminosilicate glass is used as the glass material. The aluminosilicate glass is composed of 58 mass% to 75 mass% SiO ₂ , 5 mass% to 23 mass% Al ₂ O ₃ , 3 mass% to 10 mass% Li ₂ O, and 4 mass% to 13 mass. % Na ₂ O as a main component. The molten glass material is poured onto the lower mold and then press-molded with the upper mold and the lower mold (step S12). A disk-shaped glass blank (glass base material) is formed by press molding.

The glass blank material may be formed by cutting out sheet glass (sheet glass) formed by a downdraw method or a float method with a grinding wheel. Further, the glass material is not limited to aluminosilicate glass, and may be any material.

(Glass substrate formation / grinding process)
Next, in the glass substrate formation / grinding process (step S20), the first lapping process is performed on both main surfaces of the press-molded glass blank material for the purpose of improving dimensional accuracy and shape accuracy. (Step S21). Both main surfaces of a glass blank material are the main surfaces used as the front main surface 1A and the main surface used as the back main surface 1B in FIG. 1 through each process mentioned later (henceforth, both main surfaces) Also called). For example, alumina abrasive grains having a particle size of # 400 (particle size of about 40 to 60 μm) are used, and the surface roughness Rmax is finished to about 6 μm.

After the first lapping step, a coring (inner peripheral cut) process is performed on the center portion of the glass blank using a cylindrical diamond drill or the like (step S22). By the coring process, an annular glass substrate having a hole in the center is obtained. A predetermined chamfering process may be performed on the hole in the center.

Also, the inner peripheral end surface and the outer peripheral end surface of the glass substrate are polished into a mirror surface by a brush (step S22). As the abrasive grains, a slurry containing cerium oxide abrasive grains is used.

Next, a second lapping process is performed on both main surfaces of the glass substrate (step S23). The second lapping step is performed using a double-side grinding apparatus that uses a planetary gear mechanism. Specifically, press the surface plate from above and below both main surfaces of the glass blank material, supply water, grinding liquid or lubricating liquid onto both main surfaces, and move the glass blank material and the lapping surface plate relatively. Then, the second lapping step is performed.

In the second lapping step, the approximate parallelism, flatness, thickness, etc. of the glass substrate are preliminarily adjusted, and a glass base material having an approximately flat main surface is obtained. In the second lapping step, fine abrasive grains are used as compared with the first lapping step in order to reduce the generated grinding marks. For example, by attaching fixed abrasive grains such as a diamond tile pad on a surface plate, both surfaces of the glass substrate are finished to a surface roughness Rmax of about 2 μm.

(Polishing process)
Next, in the polishing process (step S30), as a first polishing process (rough polishing), warping of the glass substrate while removing scratches remaining on both main surfaces of the glass substrate in the second lapping process (step S23). Is corrected (step S31). In the first polishing process, a double-side polishing apparatus using a planetary gear mechanism is used. For example, polishing is performed using a polishing pad such as hard velor, foamed polyurethane, or pitch-impregnated suede. As the abrasive, a slurry mainly composed of general cerium oxide abrasive grains is used. The substrate polished in the first polishing process is collected in the first polishing peeling process (step S32).

In the second polishing process (precise polishing), the glass substrate is subjected to polishing again, and minute defects remaining on both main surfaces of the glass substrate are eliminated (step S33). Both main surfaces of the glass substrate are finished to have a mirror-like surface, thereby forming a desired flatness and eliminating the warpage of the glass substrate. In the second polishing step, a double-side polishing apparatus using a planetary gear mechanism is used. For example, polishing is performed using a polishing pad which is a soft polisher made of suede or velor. As the abrasive, a slurry mainly composed of general colloidal silica that is finer than the cerium oxide used in the first polishing step is used.

Here, 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 attached to the lower surface, and the lower polishing pad 410 attached to the upper surface on the side (glass substrate side) facing the upper surface plate 300 of the lower surface plate 400 are provided.

The upper polishing pad 310 and the lower polishing pad 410 are processing tools for polishing both main surfaces of the glass substrate 1. 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.

The glass substrate is sandwiched between the upper surface plate 300 and the lower surface plate 400, and stress is applied in the thickness direction of the glass substrate by the upper surface plate 300 and the 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.

In the second polishing step (step S33), the surfaces of the upper polishing pad 310 and the lower polishing pad 410 may be cleaned. The cleaning of the surfaces of the upper polishing pad 310 and the lower polishing pad may be performed in any step in the polishing step (step S30), or may be performed in any step in the polishing step (step S30). Alternatively, it may be performed after the polishing process (step S30) ends.

After both main surfaces of the glass substrate 1 are polished once or a plurality of times, the surfaces of the upper polishing pad 310 and the lower polishing pad 410 are cleaned in the double-side polishing apparatus 2000. The surfaces of the upper polishing pad 310 and the lower polishing pad 410 may be periodically cleaned each time one or more polishings are performed, or may be cleaned irregularly.

After precision polishing using the double-side polishing apparatus, in the second polishing peeling step (step S34), the glass substrates attached to the polishing surface 311 of the upper polishing pad 310 and the polishing surface 411 of the lower polishing pad 410 are removed from the polishing pad. Ascend and peel. In order to peel and collect the glass substrate from the polishing pad, a substrate peeling jig described later is used.

(Chemical strengthening process)
After the glass substrate is washed, the chemical strengthening layer is formed on both main surfaces of the glass substrate by immersing the glass substrate in the chemical strengthening treatment liquid (step S40). After the glass substrate 1 is cleaned, the glass substrate 1 is immersed for about 30 minutes in a chemical strengthening treatment solution such as a mixed solution of potassium nitrate (70%) and sodium nitrate (30%) heated to 300 ° C. By chemical strengthening.

The alkali metal ions such as lithium ions and sodium ions contained in the glass substrate 1 are replaced by alkali metal ions such as potassium ions having a larger ion radius than these ions (ion exchange method).

Compressive stress is generated in the ion-exchanged region due to strain caused by the difference in ion radius, and both main surfaces of the glass substrate 1 are strengthened. For example, on both the main surfaces of the glass substrate 1, a chemical strengthening layer may be formed in a range from the surface of the glass substrate 1 to about 5 μm to improve the rigidity of the glass substrate 1. As described above, a glass substrate corresponding to the glass substrate 1 shown in FIG. 1 is obtained.

The glass substrate 1 may be further subjected to a polishing treatment with a machining allowance on both main surfaces of 0.1 μm to 0.5 μm. By removing the deposits remaining on the main surface of the glass substrate 1 after the chemical strengthening step, occurrence of head crashes in a magnetic disk manufactured using the glass substrate 1 is reduced. Further, by setting the machining allowance on both main surfaces in the polishing process to be 0.1 μm or more and 0.5 μm or less, the unevenness of stress generated by the chemical strengthening process does not appear on the surface. The manufacturing method of the glass substrate in the present embodiment is configured as described above.

It should be noted that a chemical strengthening step may be performed between the first polishing step (rough polishing) and the second polishing step (precision polishing).

(Washing process)
Next, the glass substrate is cleaned (step S50). By cleaning the two main surfaces of the glass substrate with detergent, pure water, ozone, IPA (isopropyl alcohol), UV (ultraviolet) ozone, or the like, the deposits attached to the two main surfaces of the glass substrate are removed.

Thereafter, the number of deposits on the surface of the glass substrate 1 is inspected using an optical defect inspection apparatus or the like.

(Magnetic thin film formation process)
The magnetic thin film layer 2 is formed by forming a magnetic film on both main surfaces (or one of the main surfaces) of the glass substrate (corresponding to the glass substrate 1 shown in FIG. 1) that has been subjected to the chemical strengthening treatment. Is done. The magnetic thin film layer includes an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoFeZr alloy, an orientation control underlayer made of Ru, a perpendicular magnetic recording layer made of a CoCrPt alloy, a protective layer made of a C system, and a lubrication made of an F system. It is formed by sequentially depositing layers. By forming the magnetic thin film layer, a perpendicular magnetic recording disk corresponding to the magnetic disk 10 shown in FIG. 2 can be obtained.

The magnetic disk in the present embodiment is an example of a perpendicular magnetic disk composed of a magnetic thin film layer. The magnetic disk may be composed of a magnetic layer or the like as a so-called in-plane magnetic disk.

(Configuration of the substrate peeling jig 20)
Next, the detailed structure of the board | substrate peeling jig | tool 20 used in the 2nd polish peeling process (step S34) mentioned above is demonstrated. FIG. 5 is a schematic diagram showing an outline of the configuration of the substrate peeling jig 20. As shown in FIG. 5, the substrate peeling jig 20 includes a nozzle 21 that discharges a fluid such as compressed air. A through passage is formed inside the nozzle 21, and a fluid is supplied between the lower polishing pad 410 and the glass substrate 1 through the through passage. One end of the through passage formed in the nozzle 21 forms a discharge port through which the fluid is discharged from the nozzle 21, and the other end is connected to a fluid supply source via a fluid supply system. The nozzle 21 is, for example, a flat nozzle having a width corresponding to the outer dimension of the glass substrate 1 at least at the discharge port.

The substrate peeling jig 20 includes a shaft portion 24 and a substrate receiving portion 25. The substrate receiving portion 25 receives and holds the glass substrate 1 that is peeled off and lifted from the polishing surface 411 of the lower polishing pad 410 by the discharged fluid. The substrate receiving portion 25 is radially attached to the outer peripheral surface of the shaft portion 24. The board | substrate receiving part 25 is a roll brush formed with the bristle material attached to the axial part 24 as a core material.

The substrate peeling jig 20 also includes a cover 22 that covers the glass substrate 1. The nozzle 21 is attached to the end of the cover 22. The substrate receiving portion 25 is also attached to the cover 22 via the shaft portion 24. The base end portion of the shaft portion 24 is attached to the center portion on the lower surface side of the top plate of the cover 22, and the substrate receiving portion 25 is attached to the outer peripheral surface of the shaft portion 24. The nozzle 21 and the shaft portion 24 are each attached to the cover 22 such that the lower end of the shaft portion 24 is positioned a predetermined distance away from the tip of the nozzle 21 in the horizontal direction.

The length of the hair of the bristle material of the substrate receiving portion 25 and the outer shape of the shaft portion 24 are adjusted so that the diameter of the substrate receiving portion 25 is larger than the hole 1H which is the central opening of the glass substrate 1. The substrate receiving portion 25 is inserted into the hole 1H in the central portion of the glass substrate 1 peeled from the lower polishing pad 410, and the hole 1H in the central portion of the glass substrate 1 is supported from the lower surface by the hair tips of the substrate receiving portion 25. ,It is configured. The diameter of the substrate receiving portion 25 is not particularly limited as long as the glass substrate 1 peeled from the lower polishing pad 410 can be held. The board | substrate receiving part 25 can hold | maintain the glass substrate 1 which has a different magnitude | size and a weight suitably by combining the diameter of the axial part 24, the length of the hair of a hair material, and the material of a hair material.

As the bristle material of the substrate receiving portion 25, the hair tips can be made flexible by using resin bristle having a diameter of about 0.2 mm, and the adhesion of scratches to the glass substrate 1 can be suppressed. As the material of the hair material, for example, nylon can be used. From the viewpoint of further reducing the adhesion of scratches to the glass substrate 1, the substrate receiving portion 25 may be configured to be rotatable. The substrate receiving portion 25 is not particularly limited as long as it is a roll member that is inserted into the hole 1H at the center of the glass substrate 1 and can support the glass substrate 1 from the lower surface side of the hole 1H. A sex sponge may be used. When a sponge is used, the inner peripheral end surface 1C of the glass substrate 1 can be supported.

The substrate peeling jig 20 includes a positioning portion 26 located on the opposite side of the nozzle 21 with respect to the substrate receiving portion 25. The positioning unit 26 determines the position of the glass substrate 1 that is moved by being pushed by the fluid discharged from the nozzle 21. The positioning unit 26 has a contact surface 27 that contacts the glass substrate 1. The glass substrate 1 moves in the surface direction on the polishing surface 411 of the lower polishing pad 410 by receiving pressure from the fluid. When the contact surface 27 of the positioning part 26 contacts the glass substrate 1 moving on the polishing surface 411, the movement of the glass substrate 1 in the surface direction is completed, and the position of the glass substrate 1 is determined. Here, the surface direction is a direction in which the polishing surface 411 of the flat lower polishing pad 410 extends, and is a direction orthogonal to the thickness direction of the lower polishing pad 410.

When the glass substrate 1 is peeled from the lower polishing pad 410 using the substrate peeling jig 20, the lower end portion of the positioning portion 26 comes into contact with the polishing surface 411 of the lower polishing pad 410. At this time, the lower end of the shaft portion 24 is separated from the polishing surface 411 by a distance slightly smaller than the thickness of the glass substrate 1, and the lower end of the substrate receiving portion 25 is separated from the polishing surface 411 by a distance slightly larger than the thickness of the glass substrate 1. Placed apart. Therefore, when the lower end portion of the positioning portion 26 is brought into contact with the polishing surface 411, the lower end of the shaft portion 24 is inserted into the hole 1H of the glass substrate 1, while the substrate receiving portion 25 is disposed so as not to enter the hole 1H. The

The positioning portion 26 is formed of a material having sufficient strength so that the glass substrate 1 moving in the surface direction does not break even if it collides. On the other hand, it is necessary to form the positioning portion 26 with a softer material than the forming material of the glass substrate 1 so that the glass substrate 1 is not damaged when the glass substrate 1 collides. For example, the positioning part 26 may be formed of a resin material such as polycarbonate.

The substrate peeling jig 20 has a grip portion (not shown) provided so that an operator can grip it with one hand. An operation lever is attached to the grip portion, and the operator can switch between supply and stop of fluid from the nozzle 21 by operating the operation lever. The substrate peeling jig 20 supports the substrate peeling jig 20 in contact with the lower polishing pad 410 when peeling the glass substrate 1 from the lower polishing pad 410. The substrate peeling jig 20 extends vertically downward from the top plate of the cover 22. May have a portion (not shown).

The substrate peeling jig 20 includes a fluid supply system that supplies a pressurized fluid such as compressed air to the nozzle 21. The fluid supply system includes a fluid supply source 28. When the fluid is compressed air, the fluid supply source 28 may be an accumulator that accumulates instrumentation air in the factory, an air compressor, or the like. The fluid supply system to the nozzle 21 includes, in order from the fluid supply source 28 side, a filter 29 that removes impurities such as dust in the fluid, an open / close valve 30 that controls the flow rate of the fluid, and a primary pressure of the fluid that is determined in advance. And a regulator 31 for reducing the pressure to a secondary pressure. If necessary, in addition to the filter 29, an oil separator or the like that removes oil in the fluid may be disposed in the fluid supply system. As the pressurized fluid, in addition to compressed air, various gases having different specific gravities or liquids such as pressurized water may be used.

(Operation of the substrate peeling jig 20)
The peeling operation | movement of the glass substrate 1 using the board | substrate peeling jig | tool 20 which has the above structure is demonstrated. 6 to 8 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the first embodiment. In the first embodiment, an example in which the glass substrate 1 is peeled from the lower polishing pad 410 by discharging compressed air from the nozzle 21 will be described. 6 to 8 and drawings to be described later, the lower polishing pad 410 on which the glass substrate 1 is placed and the fluid supply system for supplying fluid to the nozzle 21 are not shown.

First, the substrate peeling jig 20 is appropriately arranged around the glass substrate 1. As shown in FIG. 6, the substrate peeling jig 20 is positioned with respect to the glass substrate 1 by inserting the lower end of the shaft portion 24 into the hole 1 </ b> H formed in the glass substrate 1. The lower end portion of the positioning portion 26 contacts the polishing surface 411 of the lower polishing pad 410. At this time, the tip of the nozzle 21 is disposed in the vicinity of the outer peripheral end face 1 </ b> D of the glass substrate 1. The substrate receiving portion 25 is disposed above the glass substrate 1 with a predetermined interval between the front main surface 1A of the glass substrate 1.

In a state where the substrate peeling jig 20 is properly arranged, the opening / closing valve 30 is opened, and supply of compressed air from the nozzle 21 is started. Dust is removed from the compressed air supplied from the fluid supply source 28 by the filter 29, the pressure is reduced to a secondary pressure that is a predetermined set pressure by the regulator 31, and the compressed air is supplied to the substrate peeling jig 20. In addition, the pressure of the compressed air after decompressing with the regulator 31 is set to 0.1 MPa or more and 0.5 MPa, for example, 0.3 MPa. The flow rate of the compressed air is set to 100 liters / minute or more and 700 liters / minute or less.

As shown in FIG. 7, the compressed air A is discharged from the nozzle 21 toward the glass substrate 1. At this time, when the compressed air A exerts pressure on the outer peripheral end surface 1D of the glass substrate 1, the glass substrate 1 moves in a direction away from the nozzle 21 as indicated by an arrow in FIG. 7. The glass substrate 1 moved in the surface direction on the polishing surface 411 comes into contact with the contact surface 27 of the positioning portion 26, stops at that position, and does not move in the surface direction. Subsequently, when the compressed air A flows between the polishing surface 411 of the lower polishing pad 410 and the glass substrate 1, upward stress acts on the glass substrate 1 as indicated by an arrow in FIG. 8. Then, it is peeled off from the lower polishing pad 410.

The lower end of the substrate receiving portion 25 is disposed above the hole 1H in the central portion of the glass substrate 1 in a state where the outer peripheral end surface 1D is in contact with the contact surface 27 of the positioning portion 26 and the glass substrate 1 is positioned. The glass substrate 1 peeled from the lower polishing pad 410 floats while being guided by the shaft portion 24, and the substrate receiving portion 25 is inserted into the hole 1 </ b> H of the glass substrate 1. Since the outer diameter of the substrate receiving portion 25 is adjusted to be larger than the diameter of the inner peripheral end surface 1C of the glass substrate 1, the glass substrate 1 is in contact with the hair tips of the substrate receiving portion 25 while the inner peripheral end surface 1C is in contact therewith. Float up. The board | substrate receiving part 25 supports the glass substrate 1 of the floated state from the lower surface side with a hair tip. Thereby, the substrate receiving portion 25 can reliably receive and support the glass substrate 1 peeled from the lower polishing pad 410.

After holding the glass substrate 1 with the substrate receiving portion 25, the substrate peeling jig 20 is separated from the lower polishing pad 410. Then, the operator removes the glass substrate 1 held by the substrate receiving portion 25 from the front end side of the shaft portion 24 by hand. In this way, the glass substrate 1 can be peeled from the lower polishing pad 410 without generating scratches and deposits on the main surface of the glass substrate 1.

(Action / Effect)
As described above, according to the present embodiment, the compressed air A is discharged between the lower polishing pad 410 and the glass substrate 1 so that the jig does not come into contact with the surface of the glass substrate 1. The glass substrate 1 adhered to the side polishing pad 410 can be peeled off and removed. Therefore, it is possible to suppress adhesion of scratches and dirt to the main surface of the glass substrate 1 when the glass substrate 1 is peeled off.

Compressed air A is discharged from the nozzle 21 for peeling the glass substrate 1, so there is a concern that moisture is easily removed from the surface of the glass substrate 1 by the compressed air A and the glass substrate 1 is easily dried. In the present embodiment, as described above, the positioning portion 26 is provided, the glass substrate 1 is positioned at a position after the movement by the action of the compressed air A, and the substrate is so received as to float on the position. A receiving part 25 is arranged.

With this configuration, the glass substrate 1 is smoothly held by the substrate receiving portion 25, and the glass substrate 1 can be prevented from being inclined and caught on the substrate receiving portion 25 or the shaft portion 24. The held state can be obtained early. Therefore, the injection time of the compressed air A can be shortened, and the flow rate of the compressed air A discharged toward the glass substrate 1 can be reduced. Accordingly, drying of the glass substrate 1 can be suppressed, and dirt and foreign matter can be prevented from adhering to the glass substrate 1, so that a good glass substrate 1 with less deposits on the main surface can be obtained and the quality of the glass substrate 1 can be improved. can do. In addition, since the time required for peeling the glass substrate 1 can be shortened, the time required for manufacturing the glass substrate 1 can be shortened, and the productivity can be improved.

(Modification)
FIG. 9 is a schematic plan view illustrating an example of the positioning unit 26. Although the positioning part 26 may be formed in a flat plate shape, as shown in FIG. 9, it is desirable that the positioning part 26 is formed with a curvature so that the contact surface 27 facing the glass substrate 1 has a concave shape. The curvature of the concave contact surface 27 is made smaller than the curvature of the outer peripheral end surface 1D of the glass substrate 1. By defining the shape of the contact surface 27 in this way, when the glass substrate 1 that has moved under the pressure of the compressed air A is brought into contact with the contact surface 27 and stopped in the surface direction, the glass substrate 1 is specified in the surface direction. It is possible to position at the position. If it does in this way, the glass substrate 1 can be positioned more reliably and the catch of the glass substrate 1 can be suppressed more reliably.

FIG. 10 is a schematic plan view showing a modified example of the positioning portion 26. Instead of the configuration for setting the curvature of the contact surface 27 described with reference to FIG. 9, as shown in FIG. 10, a plurality of pin-shaped positioning portions 26 are provided, and the plurality of locations on the outer peripheral end surface 1 </ b> D of the glass substrate 1 are provided. The positioning part 26 may be brought into contact. Also with this configuration, the glass substrate 1 can be reliably positioned in the surface direction, and the catching of the glass substrate 1 can be more reliably suppressed.

[Embodiment 2]
FIGS. 11 to 13 are schematic views showing the respective steps during the peeling operation of the glass substrate 1 of the second embodiment. The substrate peeling jig 20 according to the second embodiment is different from the first embodiment in the arrangement of the positioning portion 26 and the substrate receiving portion 25.

Specifically, the contact surface 27 of the positioning portion 26 is inclined with respect to the normal direction of the polishing surface 411 of the lower polishing pad 410. The contact surface 27 is inclined toward the side closer to the substrate receiving portion 25 as the distance from the polishing surface 411 increases. In accordance with the inclination of the contact surface 27, the substrate receiving portion 25 and the shaft portion 24 serving as the core material of the substrate receiving portion 25 are also inclined with respect to the normal direction of the polishing surface 411. The substrate receiving portion 25 and the shaft portion 24 are inclined to the side away from the nozzle 21 as the distance from the polishing surface 411 increases.

The substrate peeling jig 20 according to the second embodiment is arranged with respect to the glass substrate 1 as shown in FIG. 11, and the compressed air A is discharged from the nozzle 21 in this state. The glass substrate 1 that receives stress from the compressed air A moves in the surface direction as shown in FIG. On the outer peripheral end surface 1D of the glass substrate 1, chamfered portions on the upper side (front main surface 1A side) and the lower side (back main surface 1B side) are formed (see FIG. 2). When the glass substrate 1 comes into contact with the contact surface 27 of the positioning portion 26, the upper chamfered portion or the corner portion formed by the upper chamfered portion and the outer peripheral end surface 1 </ b> D contacts the contact surface 27.

When the glass substrate 1 is positioned by the contact surface 27, the glass substrate 1 is lifted and separated from the polished surface 411 by the compressed air A that enters between the polished surface 411 and the glass substrate 1 as shown in FIG. 13. Substrate receiving portion 25 and shaft portion 24 are arranged so as to extend along a direction orthogonal to the main surface of glass substrate 1 in the floated state shown in FIG. Thereby, the substrate receiving portion 25 can reliably receive and support the glass substrate 1 peeled from the lower polishing pad 410.

According to the second embodiment described above, the glass substrate 1 is floated at a certain inclination and held by the substrate receiving portion 25 because the positioning portion 26 is disposed at an inclination. Since the glass substrate 1 can be kept in a certain posture, the time for jetting the compressed air A can be further shortened, and thus drying of the glass substrate 1 can be more reliably suppressed, and dirt and foreign matter on the glass substrate 1 can be suppressed. Adhesion can be reduced.

[Embodiment 3]
14 to 16 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the third embodiment. The substrate peeling jig 20 according to the third embodiment is different from the first embodiment in the arrangement of the positioning portion 26 and the substrate receiving portion 25.

Specifically, the contact surface 27 of the positioning portion 26 is inclined with respect to the normal direction of the polishing surface 411 of the lower polishing pad 410. The contact surface 27 is inclined to the side away from the substrate receiving portion 25 as it is away from the polishing surface 411. Unlike the second embodiment, the substrate receiving portion 25 and the shaft portion 24 extend along the normal direction of the polishing surface 411.

14 is arranged with respect to the glass substrate 1 as shown in FIG. 14, and the compressed air A is discharged from the nozzle 21 in this state. The glass substrate 1 that receives stress from the compressed air A moves in the surface direction as shown in FIG. 15 and contacts the contact surface 27. When the glass substrate 1 is positioned by the contact surface 27, the glass substrate 1 is lifted and peeled off from the polished surface 411 by the compressed air A entering between the polished surface 411 and the glass substrate 1 as shown in FIG. 16.

In the configuration of the first embodiment, when the glass substrate 1 starts to float, the glass substrate 1 is tilted with respect to the substrate receiving portion 25 extending in the normal direction of the polishing surface 411 because it floats from the end on the nozzle 21 side. there is a possibility. On the other hand, in the substrate peeling jig 20 according to the third embodiment, since the contact surface 27 of the positioning portion 26 is inclined, the glass that contacts the contact surface 27 after the glass substrate 1 contacts the contact surface 27. The end portion of the substrate 1 is likely to float along the contact surface 27. Therefore, when starting to float from the polishing surface 411, the glass substrate 1 floats from both ends of the nozzle 21 side and the positioning portion 26 side opposite to the nozzle 21. Can be suppressed.

Therefore, since it can suppress more that the glass substrate 1 inclines and is caught by the board | substrate receiving part 25 or the axial part 24, the injection time of compressed air A can be shortened, drying of the glass substrate 1 can be suppressed, and the glass substrate 1 can be prevented from drying. Dirt and adhesion of foreign matter can be further reduced.

[Embodiment 4]
FIGS. 17 to 19 are schematic diagrams showing the respective steps during the peeling operation of the glass substrate 1 according to the fourth embodiment. In addition to the nozzle 21 that discharges the compressed air A, the substrate peeling jig 20 according to the fourth embodiment further includes a nozzle 41 that sprays pure water in the form of a mist. The substrate peeling jig 20 uses the nozzles 21 and 41 together during the peeling operation of the glass substrate 1. In the fourth embodiment, the fluid supplied to the glass substrate 1 includes compressed air and water.

As shown in FIGS. 18 and 19, the compressed air A is discharged from the nozzle 21, and at the same time, mist water W is sprayed from the nozzle 41 to supply moisture to the glass substrate 1. If it does in this way, since the drying of the surface of the glass substrate 1 can be prevented directly, drying of the glass substrate 1 can be suppressed and the adhesion | attachment of the stain | pollution | contamination and foreign material to the glass substrate 1 can be reduced more.

[Embodiment 5]
20 to 22 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the fifth embodiment. The substrate peeling jig 20 according to the fifth embodiment includes a temporary positioning portion 46. The temporary positioning portion 46 is disposed on the nozzle 21 side with respect to the substrate receiving portion 25 at a position facing the positioning portion 26 via the substrate receiving portion 25.

As shown in FIG. 20, when the substrate peeling jig 20 is placed before peeling the glass substrate 1 from the polishing surface 411, the temporary positioning portion 46 is placed facing the outer peripheral end face 1 </ b> D of the glass substrate 1. The position of the substrate peeling jig 20 can be defined. In the first embodiment, the shaft part 24 is inserted into the hole 1H of the glass substrate 1 to position the substrate peeling jig 20. However, if the shaft part 24 accidentally contacts the main surface of the glass substrate 1, the main surface is brought into contact with the main surface. Scratches and deposits may occur.

In contrast, in the fifth embodiment, the temporary positioning portion 46 is provided, and the substrate peeling jig 20 is arranged so that the glass substrate 1 is placed between the temporary positioning portion 46 and the positioning portion 26. Since the approximate position of the substrate peeling jig 20 is adjusted using the temporary positioning portion 46, the contact of the shaft portion 24 with the glass substrate 1 can be surely prevented, and the occurrence of scratches on the main surface can be suppressed. Therefore, the surface quality of the main surface of the glass substrate 1 can be improved.

In the fifth embodiment, since the substrate peeling jig 20 is arranged using the temporary positioning portion 46, it is not necessary to use the shaft portion 24 for positioning the substrate peeling jig 20. Therefore, unlike the first embodiment, the lower end of the shaft portion 24 and the lower end of the substrate receiving portion 25 are arranged at the same distance from the polishing surface 411, and the lower end of the shaft portion 24 is located with respect to the lower end of the substrate receiving portion 25. The lower end of the shaft portion 24 is not inserted into the hole 1H of the glass substrate 1 without protruding.

[Embodiment 6]
FIG. 23 is a schematic diagram showing an outline of the configuration of the substrate peeling jig 20 according to the sixth embodiment. The substrate peeling jig 20 according to the sixth embodiment further includes a light projecting unit 48 that irradiates light L to the tip of the shaft 24, that is, the end of the shaft 24 on the side facing the polishing surface 411. The light projecting unit 48 is, for example, a light emitting diode. The light projecting unit 48 is irradiated with the light L at the tip of the shaft part 24 for positioning the substrate peeling jig 20 by being inserted into the hole 1H of the glass substrate 1, thereby improving the visibility of the tip of the shaft part 24. Yes. That is, by illuminating the tip end of the shaft portion 24 with the light projecting portion 48, the operator can easily see the tip end of the shaft portion 24.

Thereby, the position of the tip of the shaft portion 24 can be accurately grasped, so that the tip of the shaft portion 24 is more reliably inserted into the hole 1H of the glass substrate 1 and the shaft portion 24 is positioned when the substrate peeling jig 20 is positioned. Accidental contact with the main surface of the glass substrate 1 can be avoided. Accordingly, it is possible to suppress the generation of scratches and deposits on the main surface of the glass substrate 1, so that the surface quality of the main surface of the glass substrate 1 can be improved.

[Embodiment 7]
24 to 26 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the seventh embodiment. The substrate peeling jig 20 according to the seventh embodiment further includes an elastic body 34 that covers the tip end portion of the shaft portion 24, that is, the end portion of the shaft portion 24 on the side facing the polishing surface 411. The elastic body 34 is disposed so as to cover the distal end surface of the shaft portion 24 facing the polishing surface 411 and the outer peripheral surface of the shaft portion 24 from the distal end portion of the shaft portion 24 to the substrate receiving portion 25. Thereby, the board | substrate peeling jig | tool 20 is comprised so that the axial part 24 at the front end side may not be exposed outside. The elastic body 34 is made of a softer material than the forming material of the lower polishing pad 410. For example, the elastic body 34 may be formed using urethane or sponge.

By covering the outer peripheral surface of the shaft portion 24 with the elastic body 34, the glass substrate 1 is pivoted when moving in the surface direction of the glass substrate 1 shown in FIG. 25 or when the glass substrate 1 shown in FIG. Direct contact with the portion 24 can be prevented. Even if the glass substrate 1 is close to the shaft portion 24, it is the soft elastic body 34 that contacts the glass substrate 1, so that it is possible to more reliably prevent the glass substrate 1 from being damaged.

[Embodiment 8]
FIG. 27 is a schematic diagram illustrating an outline of the configuration of the substrate peeling jig 20 according to the eighth embodiment. As shown in FIG. 27 in plan view of the glass substrate 1, in the substrate peeling jig 20 of the eighth embodiment, the positioning portion 26 is provided so as to surround three sides of the glass substrate 1. In three directions excluding the direction in which the nozzle 21 is arranged with respect to the glass substrate 1, the periphery of the glass substrate 1 is surrounded by a positioning portion 26. Other glass substrates 101, 102, and 103 are disposed around the glass substrate 1. The positioning unit 26 functions as a partition that partitions the glass substrate 1 and the other glass substrates 101, 102, 103 adjacent to the glass substrate 1.

According to the configuration of the positioning unit 26 of the eighth embodiment, the compressed air A discharged from the nozzle 21 toward the glass substrate 1 is changed in direction by the positioning unit 26, as in the backflow AR shown in FIG. , Flows toward the nozzle 21 side. Therefore, the compressed air A discharged to the glass substrate 1 does not leak to the other adjacent glass substrates 101, 102, 103, and the other glass substrates 101, 102, 103 receive pressure from the compressed air A and face Never move in the direction. Accordingly, since the collision between the glass substrate 1 and the other glass substrates 101, 102, 103 or the collision between the other glass substrates 101, 102, 103 can be prevented, the glass substrate 1 and the other glass substrates 101, 102, 103 are prevented. It is possible to reliably avoid the occurrence of scratches due to collision.

[Embodiment 9]
28 to 30 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the ninth embodiment. In the substrate peeling jig 20 according to the ninth embodiment, the substrate receiving portion 25 is formed in a shape that tapers toward the tip portion of the shaft portion 24, that is, the end portion of the shaft portion 24 on the side facing the polishing surface 411. Yes. For example, the outer peripheral surface of the substrate receiving portion 25 may be formed in a conical surface shape, the substrate receiving portion 25 is formed by a plurality of fins extending along the extending direction of the shaft portion 24, and the side surfaces of the fins are triangular or It may have a trapezoidal shape. The substrate receiving portion 25 is not limited to a shape that continuously tapers toward the distal end portion of the shaft portion 24, and may have a shape that gradually decreases in diameter stepwise toward the distal end portion of the shaft portion 24. .

Preferably, as shown in FIGS. 28 to 30, the shaft portion 24 and the substrate receiving portion 25 may be formed so that the outer diameters thereof are equal at the end portion facing the polishing surface 411.

By forming the substrate receiving portion 25 as in the ninth embodiment, the substrate receiving portion 25 can more easily hold the glass substrate 1 floating from the polishing surface 411. Since the resistance when the substrate receiving portion 25 is inserted into the hole 1H of the glass substrate 1 is reduced, it is possible to suppress the substrate receiving portion 25 from hindering the glass substrate 1 from floating. Therefore, since it can further suppress that the glass substrate 1 is caught by the substrate receiving part 25, the spray time of the compressed air A can be shortened, and drying of the glass substrate 1 can be suppressed and dirt and foreign matter adhesion to the glass substrate 1 can be further reduced. can do.

[Embodiment 10]
31, 33 and 34 are schematic diagrams showing each process during the peeling operation of the glass substrate 1 of the tenth embodiment. FIG. 32 is a schematic diagram showing the area XXXII shown in FIG. 31 in an enlarged manner. In the substrate peeling jig 20 according to the tenth embodiment, the contact surface 27 of the positioning portion 26 is formed in a shape in which the end portion on the polishing surface 411 side is bent toward the substrate receiving portion 25 side.

Specifically, as shown in detail in FIG. 32, the positioning portion 26 has a hook-like portion 56 that protrudes toward the substrate receiving portion 25 at the end on the polishing surface 411 side. The positioning portion 26 increases in thickness at the flange-shaped portion 56, and the thickness of the flange-shaped portion 56 gradually increases toward the tip that faces the polishing surface 411 side. The contact surface 27 has a tapered surface 57 that is inclined with respect to the normal direction of the polishing surface 411 of the lower polishing pad 410. The taper surface 57 is inclined with respect to the normal direction of the polishing surface 411 toward the side away from the substrate receiving portion 25 as the distance from the polishing surface 411 increases. The contact surface 27 is bent at the boundary between the portion extending in the normal direction of the polishing surface 411 and the tapered surface 57.

By forming the contact surface 27 into a bent shape, when the glass substrate 1 shown in FIG. 33 moves in the surface direction by the compressed air A and contacts the contact surface 27, the glass from the contact surface 27 to the glass substrate 1 is reduced. A stress in a direction to scoop up the substrate 1 from the polishing surface 411 acts. After the glass substrate 1 receiving pressure from the compressed air A comes into contact with the contact surface 27, the end of the glass substrate 1 that contacts the contact surface 27 is likely to float along the contact surface 27. Therefore, when starting to float from the polishing surface 411, the glass substrate 1 floats from both ends on the nozzle 21 side and the positioning portion 26 side, so that the inclination of the glass substrate 1 can be suppressed.

Therefore, since it can suppress more that the glass substrate 1 inclines and is caught by the board | substrate receiving part 25 or the axial part 24, the injection time of compressed air A can be shortened, drying of the glass substrate 1 can be suppressed, and the glass substrate 1 can be prevented from drying. Dirt and adhesion of foreign matter can be further reduced.

[Embodiment 11]
35 to 37 are schematic views showing respective steps during the peeling operation of the glass substrate 1 of the eleventh embodiment. The substrate peeling jig 20 of the eleventh embodiment has the same configuration as that of the second embodiment, and includes a nozzle 41 that discharges high-pressure water W instead of the nozzle 21 that discharges compressed air A. This is different from Form 2. The fluid discharged from the nozzle 41 is high-pressure water W. The pressure of the high-pressure water W can be set to 1.0 MPa or more and 10 MPa or less, and the flow rate of the high-pressure water W can be set to 0.5 liter / min or more and 2.0 liter / min.

When the high-pressure water W is discharged from the nozzle 41, the glass substrate 1 that has received stress from the high-pressure water W moves in the surface direction and contacts the contact surface 27 as shown in FIG. When the glass substrate 1 is positioned by the contact surface 27, the glass substrate 1 is lifted and separated from the polished surface 411 by the high-pressure water W that enters between the polished surface 411 and the glass substrate 1 as shown in FIG. 37. The substrate receiving portion 25 reliably receives and supports the glass substrate 1 peeled from the lower polishing pad 410.

According to the eleventh embodiment, in addition to the effect of the second embodiment that shortens the injection time of the compressed air A by keeping the glass substrate 1 in a certain posture, the high-pressure water W is supplied to the glass substrate 1. An effect of directly preventing drying of the surface of the glass substrate 1 can be obtained. Therefore, drying of the glass substrate 1 can be more reliably suppressed, and dirt and foreign matter adhesion to the glass substrate 1 can be reduced.

Hereinafter, each example and comparative example of the method of manufacturing the information recording medium will be described. According to the flowchart shown in FIG. 3, information recording media of Examples and Comparative Examples were manufactured. An example of peeling the glass substrate 1 from the polishing surface 411 of the lower polishing pad 410 using the substrate peeling jig 20 according to the above-described first to eleventh embodiments after the second polishing step (step S33). Examples 1 to 11 were used respectively. On the other hand, the example which peels the glass substrate 1 from the polishing surface 411 of the lower side polishing pad 410 using the conventional board | substrate peeling jig | tool which does not have the positioning part 26 was made into the comparative example.

In each example and comparative example, a total of 100 glass substrates were extracted from the glass substrate manufactured according to each step shown in FIG. 3, and the non-defective rate of the substrate was inspected after the cleaning step (step S50). Furthermore, the cause of the defect in the glass substrate determined to be defective was inspected. As a test apparatus, an optical defect inspection apparatus Candela-OSA6100 manufactured by KLA-Tencor was used.

In the sampling non-defective product inspection, it is evaluated as “particularly good” when the yield, that is, the proportion of non-defective products is 92% or more, and is evaluated as “good” when the yield is 86% or more and less than 92%. If it was less than 86%, it was evaluated as “slightly poor”. In the attached matter evaluation inspection, a product having an adhesion count number of 10 or more is regarded as a defective product, and if the number of defective products out of 100 is less than 5, it is evaluated as “particularly good” and the number of defective products is When it was 5 or more and 10 or less, it was evaluated as “good”, and when the number of defective products was 11 or more, it was evaluated as “slightly defective”. In the scratch evaluation inspection, a product with a clear scratch (scratch) is regarded as a defective product, and if the number of defective products out of 100 is less than 4, it is evaluated as “particularly good”. Was evaluated as “good” when 4 or more and 7 or less, and “slightly defective” when the number of defective products was 8 or more.

In addition, after the information recording medium produced through the magnetic thin film forming step (step S60) was incorporated into the drive, the read / write characteristics were evaluated, and the recording characteristics of the information recording medium were inspected. If an information recording medium that cannot be read or has a reading error in the evaluation of read / write characteristics is regarded as a defective product, and the number of defective products out of 100 is less than 4, it is evaluated as “particularly good” and the number of defective products is 4 If it was 6 or less, it was evaluated as “good”, and if the number of defective products was 7 or more, it was evaluated as “slightly defective”.

Table 1 shows the results of inspection of defective products, breakdown of defective products, and inspection of recording characteristics of the glass substrates of Examples 1 to 11 and Comparative Example.

As shown in Table 1, the glass substrate of the comparative example has a lot of deposits on the glass substrate and a lot of scratches, and it is evaluated as “slightly bad” in any inspection, and the evaluation of the read / write characteristics is also possible. “Slightly bad”. On the other hand, the glass substrates of Examples 1 to 11 were evaluated as “particularly good” or “good” in all inspections, and the evaluation of the read / write characteristics was also “particularly good” or “good”.

In the above embodiment, the substrate peeling jig is used in the second polishing peeling step after the second polishing step, but the same substrate peeling jig may be used in the first polishing peeling step after the first polishing step. .

Although the embodiments of the present invention have been described as above, the configurations of the embodiments may be combined as appropriate. In addition, it should be considered that the embodiments and examples disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The present invention can be particularly advantageously applied to a manufacturing process of a magnetic disk glass substrate for a hard disk, a manufacturing process of various semiconductor wafers, and the like.

1 glass substrate, 1A front main surface, 1B back main surface, 1H hole, 10 magnetic disk, 20 substrate peeling jig, 21, 41 nozzle, 24 shaft portion, 25 substrate receiving portion, 26 positioning portion, 27 contact surface, 34 Elastic body, 46 Temporary positioning part, 48 Light projecting part, 56 Hook-shaped part, 57 Tapered surface, 300 Upper surface plate, 310 Upper polishing pad, 311 411 Polishing surface, 400 Lower surface plate, 410 Lower polishing pad, A compression Air, W water.

Claims (12)

1. A method for manufacturing an information recording medium, comprising: a glass substrate having a main surface; and a magnetic thin film layer formed on the main surface of the glass substrate,
   Polishing the main surface by pressing the glass substrate against a polishing surface of a surface plate;
   Removing the glass substrate from the polished surface using a substrate peeling jig,
   The substrate peeling jig is
   A nozzle for discharging fluid;
   A contact portion that contacts the glass substrate that moves in the surface direction of the polishing surface by the fluid; and a positioning portion that determines a position of the glass substrate;
   A substrate receiving portion that receives and holds the glass substrate that is lifted from the polishing surface by the fluid.
2. 2. The method of manufacturing an information recording medium according to claim 1, wherein the contact surface is inclined toward a side closer to the substrate receiving portion as the distance from the polishing surface is longer than a normal line direction of the polishing surface.
3. 2. The method of manufacturing an information recording medium according to claim 1, wherein the contact surface is inclined toward the side away from the substrate receiving portion as it is away from the polishing surface with respect to the normal direction of the polishing surface.
4. 2. The method of manufacturing an information recording medium according to claim 1, wherein the contact surface is formed in a shape in which an end portion on the polishing surface side is bent toward the substrate receiving portion side.
5. The substrate peeling jig includes a shaft portion, and the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion,
   5. The information recording medium manufacturing method according to claim 1, wherein the substrate peeling jig further includes an elastic body that covers an end of the shaft portion on the polishing surface side. 6.
6. The method for manufacturing an information recording medium according to claim 1, wherein the positioning portion surrounds three sides of the glass substrate.
7. The method for manufacturing an information recording medium according to any one of claims 1 to 6, wherein the fluid is high-pressure water.
8. The method for manufacturing an information recording medium according to any one of claims 1 to 6, wherein the fluid includes compressed air and water.
9. The substrate peeling jig includes a temporary positioning portion disposed at a position facing the positioning portion via the substrate receiving portion,
   The position of the said board | substrate peeling jig | tool is prescribed | regulated by arrange | positioning the temporary positioning part facing the outer peripheral end surface of the said glass substrate before peeling the said glass substrate from the said grinding | polishing surface. 9. A method for producing an information recording medium according to any one of 8 above.
10. The substrate peeling jig includes a shaft portion, and the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion,
    The method for manufacturing an information recording medium according to claim 1, wherein the substrate peeling jig further includes a light projecting unit that irradiates light to an end of the shaft portion on the polishing surface side.
11. The substrate peeling jig includes a shaft portion, and the substrate receiving portion is provided radially on the outer peripheral surface of the shaft portion,
    The method for manufacturing an information recording medium according to claim 1, wherein the substrate receiving portion tapers toward an end portion of the shaft portion on the polishing surface side.
12. A substrate peeling jig that is used to peel a glass substrate pressed against a polishing surface of a surface plate and whose main surface is polished from the polishing surface,
    A nozzle for discharging fluid;
    A contact portion that contacts the glass substrate that moves in the surface direction of the polishing surface by the fluid; and a positioning portion that determines a position of the glass substrate;
    A substrate receiving part that receives and holds the glass substrate that is lifted from the polishing surface by the fluid.

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