JP2012051072A - Method for manufacturing disk substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a disk substrate capable of reducing a difference in a polishing amount of both sides when polishing the disk substrate by a polishing machine, and reducing the difference in the polishing amount resulting from different setting positions of the disk substrate.SOLUTION: The method for manufacturing the disk substrate includes steps of setting two measurement boards 100 each having a measurement groove 103 formed on a surface thereof so that the measurement grooves 103 respectively face a first-side polishing side of the polishing machine and a second-side polishing side thereof; polishing the two measurement boards 100 by the polishing machine; measuring post-polishing depths of the measurement grooves 103 in the two measurement boards 100, and adjusting polishing conditions of the both sides of a glass substrate by the polishing machine.

Description

  The present invention relates to a method for manufacturing a disk-shaped substrate such as a glass substrate for a magnetic recording medium.

  In recent years, production of information recording media such as magnetic disks has been activated in response to increasing demand for recording media. Here, as a disk-shaped substrate used as a substrate for a magnetic disk, an aluminum substrate and a glass substrate are widely used. This aluminum substrate is characterized by high workability and low cost, and one glass substrate is characterized by excellent strength, surface smoothness and flatness. In particular, recently, the demand for miniaturization and high density of the disk substrate has been remarkably increased, and the degree of attention of the glass substrate capable of achieving high density with small roughness of the surface of the substrate has increased.

In Patent Document 1, a glass substrate for an information recording medium has a glass base plate formed into a disk shape by shape processing, chemically strengthened by chemical strengthening treatment, and then washed by cleaning treatment, and then lapped. In lapping and the like, the surface of the glass base plate is polished using a pair of surface plates so that the main surface on the front side and the main surface on the back side of the glass base plate have the same polishing amount. A method for manufacturing a glass substrate for an information recording medium is disclosed.
Patent Document 2 discloses a method for manufacturing a glass substrate having a main surface used for a recording disk having a small waviness of 0.6 nm or less, having a disk shape, and different in thickness. A glass substrate preparation step for preparing a plurality of glass substrates having a difference of 2 μm or less, and a plurality of glass substrates are collectively clamped with a polishing pad from above and below so that a set polishing amount for a main surface on one side is 9 μm or more. Including a glass substrate polishing step of simultaneously polishing a plurality of glass substrates.

JP 2006-324006 A JP 2009-279696 A

Here, when a disk-shaped substrate such as a glass substrate is polished by a polishing apparatus, both surfaces of the disk-shaped substrate are usually polished. However, one surface is preferentially polished, and there may be a difference in the polishing amount between one surface and the other surface. In addition, the polishing amount may be different depending on the position where the disk-shaped substrate is arranged.
The present invention makes it possible to reduce the difference in the polishing amount on both sides when polishing a disk-shaped substrate with a polishing apparatus, and to reduce the difference in the polishing amount due to the difference in the position where the disk-shaped substrate is disposed. It is an object of the present invention to provide a method for manufacturing a disk-shaped substrate that can be used.

  In order to achieve this object, a method for manufacturing a disk-shaped substrate according to the present invention is a method for manufacturing a disk-shaped substrate in which a first surface and a second surface of a plurality of disk-shaped substrates are simultaneously polished using a polishing apparatus. The first measurement substrate having the measurement groove formed on the surface is arranged in the polishing apparatus so that the measurement groove faces the side of the polishing apparatus on which the first surface is polished, and the second measurement structure is formed on the surface. The measurement substrate is arranged in the polishing device so that the measurement groove faces the second surface of the polishing device, and the first measurement substrate and the second measurement substrate arranged in the polishing device are polished. And measuring the depth after polishing of the measurement groove of the first measurement substrate and the measurement groove of the second measurement substrate, and adjusting the polishing conditions on both sides of the disk-shaped substrate by the polishing apparatus. .

  Here, the measurement groove of the first measurement substrate and the measurement groove of the second measurement substrate are formed on the first surfaces of the first measurement substrate and the second measurement substrate, and are the first of both surfaces of the polishing apparatus. The first measurement substrate is placed on the polishing apparatus with the first surface of the first measurement substrate facing the surface to be polished, and the second surface opposite to the first surface of both surfaces of the polishing apparatus is The second measurement substrate can be placed in the polishing apparatus with the first surface of the second measurement substrate facing the side to be polished. In this case, the polishing conditions are adjusted by the amount of polishing on the first surface of the polishing apparatus calculated by measuring the depth of the measurement groove of the first measurement substrate and the depth of the measurement groove of the second measurement substrate. It is preferable to adjust so as to suppress the difference between the polishing amount on the second surface.

  The measurement groove of the first measurement substrate and the measurement groove of the second measurement substrate can be formed on both surfaces of the first measurement substrate and the second measurement substrate. In this case, the adjustment of the polishing conditions suppresses the difference in the polishing amount of the polishing apparatus calculated by measuring the depth of the measurement groove of the first measurement substrate and the depth of the measurement groove of the second measurement substrate. It is preferable to adjust so that it may do.

Further, the disc-shaped substrate is polished by a pre-polishing step for rough polishing of the disc-shaped substrate and a post-polishing step for precise polishing of the disc-shaped substrate. In the pre-polishing step, a measurement substrate in which no measurement groove is formed on the surface is used. It is preferable that the polishing conditions are adjusted, and in the subsequent polishing step, the polishing conditions are adjusted using the first measurement substrate and the second measurement substrate having measurement grooves formed on the surface.
Furthermore, it is preferable that the disk-shaped substrate has a compressive stress layer formed on both sides, and the polishing conditions are adjusted so as to remove the compressive stress layer.

  According to the present invention, when a disk-shaped substrate is polished by a polishing apparatus, a phenomenon in which one surface is preferentially polished can be suppressed, and the difference in polishing amount between both surfaces can be further reduced. Can be provided.

(A)-(c) is the figure which showed the manufacturing process of the disk shaped board | substrate (disk board | substrate) to which this Embodiment is applied. (D)-(g) is the figure which showed the manufacturing process of the disk shaped board | substrate (disk board | substrate) to which this Embodiment is applied. (H)-(j) is the figure which showed the manufacturing process of the disk shaped board | substrate (disk board | substrate) to which this Embodiment is applied. It is a figure explaining the structure of the grinding machine. It is the figure explaining the holder in more detail. It is the figure which showed an example of the brush used in an inner periphery grinding | polishing process. (A) is the perspective view explaining the 1st example of the measurement board | substrate used in order to adjust the grinding | polishing conditions of a grinding machine. (B) is Vb-Vb sectional drawing of the measurement board | substrate shown to (a). It is the flowchart explaining the procedure which adjusts the grinding | polishing conditions of a grinding machine using the measurement board | substrate shown to Fig.5 (a)-(b). (A) is the perspective view explaining the 2nd example of the measurement board | substrate used in order to adjust the grinding | polishing conditions of a grinding machine. (B) is VIIb-VIIb sectional drawing of the measurement board | substrate shown to (a). It is the flowchart explaining the procedure which adjusts the grinding | polishing conditions of a grinding machine using the measurement board | substrate shown to Fig.7 (a)-(b). It is a figure explaining the other example which measures the difference of the grinding | polishing amount in both surfaces of a glass substrate.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIGS. 1-1 (a) to (c), FIGS. 1-2 (d) to (g), and FIGS. 1-3 (h) to (j) illustrate the manufacture of a disk-shaped substrate to which the present embodiment is applied. It is the figure which showed the process.

(Primary lapping process)
FIG. 1-1 (a) shows the primary lapping process. In this step, first, grinding (lapping) is performed for the first time by a grinding machine (grinding device, lapping machine) 40, and the surface 11 of a glass substrate (workpiece) 10 as an example of a disk-shaped substrate is ground smoothly.
Here, FIG. 2 is a diagram illustrating the structure of the grinding machine 40.
The grinding machine 40 shown in FIG. 2 includes a lower surface plate 21a on which the glass substrate 10 is placed, and an upper surface plate 21b for applying pressure necessary for pressing and grinding the glass substrate 10 from above. Yes.
Here, a tooth portion 42 is provided on the outer peripheral portion of the lower surface plate 21a, and a sun gear 44 is provided on the central portion of the lower surface plate 21a. Further, the lower surface plate 21a is provided with a disk-shaped holder (carrier) 30 for positioning the glass substrate 10 when grinding is performed.
In the grinding machine 40 shown in FIG. 2, five holders 30 are installed. A tooth portion 32 is provided on the outer peripheral portion of the holder 30, and meshes with both the tooth portion 42 and the sun gear 44 of the lower surface plate 21a. Further, the lower surface plate 21a and the upper surface plate 21b are provided with rotation shafts 46a and 46b for rotating them at the center.

In this primary lapping step, the glass substrate 10 is first placed on the lower surface plate 21a of the grinding machine 40 using the holder 30.
FIG. 3 is a diagram illustrating the holder 30 in more detail. As described above, the holder 30 shown in FIG. 3 includes the tooth portion 32 on the outer peripheral portion. A plurality of circular holes 34 in which the glass substrate 10 is placed when grinding is provided. The diameter of the hole 34 is slightly larger than the diameter of the glass substrate 10. By doing in this way, it can suppress that extra stress is applied to a part of outer periphery edge of the glass substrate 10 when grinding, Therefore The outer periphery edge of the glass substrate 10 becomes difficult to be damaged. In the present embodiment, the diameter of the hole 34 is, for example, about 1 mm larger than the diameter of the glass substrate 10. The holes 34 are arranged at substantially equal intervals. In the case of the present embodiment, for example, 35 holes 34 are opened.

  As a material of the holder 30, for example, an epoxy resin reinforced by mixing aramid fiber or glass fiber can be used. Further, the thickness of the holder 30 is made thinner than the finished thickness of the glass substrate 10 in this step so as to come into contact with the upper surface plate 21b during grinding in this step and not hinder the grinding. For example, if the finished thickness of the glass substrate 10 is 1 mm, the thickness of the holder 30 is 0.2 mm to 0.6 mm thinner than that.

After the glass substrate 10 is placed in the hole 34 of the holder 30, the upper surface plate 21b is moved until it comes into contact with the glass substrate 10, and the grinding machine 40 is operated.
The operation of the grinding machine 40 at this time will be described with reference to FIG. When operating the grinding machine 40, the upper rotating shaft 46b in the drawing is rotated in one direction, and the upper surface plate 21b is rotated in the same one direction. Further, the lower rotating shaft 46a in the figure is rotated in the opposite direction to the rotation of the rotating shaft 46b, and the lower surface plate 21a is rotated in the same direction as the rotating shaft 46a. Thereby, the tooth part 42 of the lower surface plate 21a also rotates in the same direction as the rotating shaft 46a. The sun gear 44 at the center also rotates in the same direction as the rotation shaft 46a.
Thus, by rotating the upper surface plate 21b, the lower surface plate 21a, and the sun gear 44, the holder 30 that meshes with these gears performs a so-called planetary motion in which the rotation motion and the revolution motion are combined. Similarly, the glass substrate 10 fitted in the holder 30 also performs planetary motion. By doing in this way, grinding of the glass substrate 10 can be performed more accurately and rapidly.

  In the present embodiment, grinding can be performed using an abrasive. Although it does not specifically limit as an abrasive, For example, the abrasives which consist of an alumina or a diamond can be used by slurrying. Or you may use the grindstone which these abrasives disperse | distributed and contained in the upper surface plate 21b and the lower surface plate 21a.

(Inner and outer grinding process)
FIG. 1-1 (b) shows the inner and outer peripheral grinding steps. In this step, grinding that is roughing of the inner peripheral surface of the opening 12 and the outer peripheral surface of the outer periphery 13 of the glass substrate 10 is performed. In the present embodiment, the inner peripheral surface and the outer peripheral surface are simultaneously ground. Specifically, the opening 12 provided in the center of the glass substrate 10 is ground by the inner peripheral grindstone 22, and the outer periphery 13 of the glass substrate 10 is ground by the outer peripheral grindstone 23. At this time, the inner peripheral surface 22 and the outer peripheral surface 23 of the glass substrate 10 are sandwiched between the inner peripheral grindstone 22 and the outer peripheral grindstone 23 and are simultaneously processed. This makes it easy to ensure the concentricity between the inner diameter and the outer diameter.
In the present embodiment, the inner peripheral grindstone 22 and the outer peripheral grindstone 23 have a wavy surface. Therefore, not only can the inner peripheral surface of the opening 12 and the outer peripheral surface of the outer periphery 13 of the glass substrate 10 be ground, but also the chamfering of the edges of the opening 12 and the outer periphery 13 can be performed together.

(Inner grinding process)
FIG. 1-1 (c) shows the inner periphery polishing step. In this step, polishing is performed to further smooth the inner peripheral surface of the aperture 12 of the glass substrate 10 that has been ground in the inner and outer periphery grinding step shown in FIG.
Specifically, the glass substrate 10 is first laminated and set in a holder (not shown). And the brush 24 is inserted in the center of the opening 12 of the glass substrate 10 set to this holder. Then, the inner peripheral surface of the glass substrate 10 is polished by rotating the brush 24 at a high speed while pouring the polishing liquid into the opening 12 of the glass substrate 10. In the present embodiment, since the brush 24 is used for polishing, the inner peripheral surface of the glass substrate 10 is polished, and the chamfered portion of the edge of the opening 12 performed in the inner and outer peripheral grinding step described above is also the same. Can be polished. As the polishing liquid, for example, a slurry obtained by dispersing cerium oxide abrasive grains in water can be used.

  FIG. 4 is a view showing an example of the brush 24 used in the inner periphery polishing step. The brush 24 includes a brush portion 241 formed by arranging hair tips in a spiral shape, and a shaft 242 formed continuously at both ends of the brush portion 241 and forming one end and the other end. Yes. When the inner peripheral surface of a small-diameter disk such as 0.85 inch is polished as the opening 12 of the glass substrate 10, it is necessary to make the core of the brush 24 thinner. In this case, in this embodiment, for example, a plurality of wires (material: for example, mild steel wire (SWRM), hard steel wire (SWRH), stainless steel wire (SUSW), brass wire (BSW), workability, rigidity, etc. The brush portion 241 is formed by sandwiching brush hair (material: for example, nylon (trade name of DuPont)) and twisting the wire in which the hair is sandwiched. By twisting this wire to form the brush portion 241, the brush bristles formed on the brush portion 241 can be spiraled, and the polishing liquid is passed through the opening 12 of the inserted glass substrate 10. It is possible to flow in the axial direction. Therefore, the polishing liquid can be transported satisfactorily.

(Secondary lap process)
FIG. 1-2 (d) shows the secondary lapping process. In this step, the surface 11 of the glass substrate 10 that has been ground in the primary lapping step shown in FIG. 1-1 (a) is ground more smoothly by grinding again.
As a device for performing grinding in the secondary lapping step, the grinding machine 40 shown in FIG. 1-1 (a) can be used. The grinding method, conditions, etc. can be performed in the same manner as in the case described with reference to FIG. In the present embodiment, the primary lapping step and the secondary lapping step can be grasped as grinding steps for grinding the glass substrate 10.

(Outer periphery polishing process)
FIG. 1-2 (e) shows the outer periphery polishing step. In this step, polishing is performed to further smooth the outer peripheral surface of the outer periphery 13 of the glass substrate 10 subjected to rough grinding in the inner and outer peripheral grinding step shown in FIG.
Specifically, the glass substrate 10 is first laminated on the hole 12 portion of the glass substrate 10 through the jig 25, and the glass substrate 10 is set on the jig 25. And while pouring polishing liquid into the location of the outer periphery 13 of the glass substrate 10, it is made to contact the glass substrate 10 which laminated | stacked the brush 26, and is rotated at high speed. Thereby, the outer peripheral surface of the glass substrate 10 can be grind | polished. In the present embodiment, since the brush 26 is used for polishing, the outer peripheral surface of the glass substrate 10 is polished, and the chamfered portion of the edge of the outer periphery 13 performed in the inner and outer peripheral grinding process described above is also polished. can do. As the polishing liquid, as in the case of the inner peripheral polishing step, for example, a slurry obtained by dispersing cerium oxide abrasive grains in water can be used.

(Strengthening layer forming process)
FIG. 1-2 (f) shows the reinforcing layer forming step. In this step, a reinforcing layer (compressive stress layer) is formed on the surface of the glass substrate 10 in order to strengthen the surface of the glass substrate 10. The reinforcing layer can be formed by ion-substituting alkali metal ions such as sodium ions on the surface of the glass substrate 10 with alkali metal ions such as potassium ions having a larger ion radius. That is, when such ion exchange is performed, a compressive stress is generated on the surface of the glass substrate 10 due to distortion caused by a difference in ion radius, and thus the surface of the glass substrate 10 is strengthened.
In the present embodiment, such ion exchange is performed by immersing the glass substrate 10 in a heated strengthening treatment liquid. As the strengthening treatment liquid, for example, a molten salt containing potassium ions or a molten salt containing potassium ions and sodium ions can be used. More specifically, potassium, sodium nitrate, carbonate, sulfate, a mixed molten salt thereof, or the like is used.

  In the present embodiment, it is necessary to reinforce the inner peripheral surface of the aperture 12 and the outer peripheral surface of the outer periphery 13 of the glass substrate 10. When the reinforcing layer is present on the main surface or the like which is another surface, the stress generated by providing the reinforcing layer is not uniform between both surfaces of the glass substrate 10, and the glass substrate 10 may be warped. Therefore, from the viewpoint of balancing the stress between both surfaces of the glass substrate 10, the reinforcing layer formed on the glass substrate 10 other than the inner peripheral surface of the aperture 12 and the outer peripheral surface of the outer periphery 13 is removed in the polishing step described later. Is required.

(Primary polishing process)
FIG. 1-2 (g) shows the primary polishing process. In this step, the surface 11 of the glass substrate 10 that has been ground in the secondary lapping step shown in FIG. 1-2D is polished (polishing) using a polishing machine (polishing apparatus, polishing machine) 50. It polishes by doing and raises smoothness further. The polishing machine 50 has substantially the same configuration as the grinding machine 40 described above. That is, a lower surface plate 21a on which the glass substrate 10 is placed and an upper surface plate 21b for applying pressure necessary for pressing and polishing the glass substrate 10 from above are provided. Then, the glass substrate 10 is placed on the lower surface plate 21a of the polishing machine 50 using the holder 30, and the upper surface plate 21b, the lower surface plate 21a, and the sun gear 44 are rotated to polish the glass substrate 10. However, as shown below, materials used for polishing are partially different.
In the present embodiment, polishing can be performed using, for example, a hard polishing cloth formed of urethane and using a polishing liquid in which cerium oxide abrasive grains and the like are dispersed in water to form a slurry.

(Secondary polishing process)
FIG. 1-3 (h) shows the secondary polishing process. In this step, the surface 11 of the glass substrate 10 that has been polished in the primary polishing step shown in FIG. 1-2 (f) is further polished by precision polishing, and the final finish of the surface 11 is completed. Do.
In this embodiment, when performing this polishing, for example, a suede-like soft polishing cloth is used, and a polishing liquid in which cerium oxide abrasive grains or colloidal silica is dispersed in a dispersion medium such as water and slurried is used. be able to. In the present embodiment, the primary polishing process and the secondary polishing process can be grasped as polishing processes for polishing the glass substrate using the polishing machine 50. Further, as described above, it is necessary to remove the reinforcing layer formed in the reinforcing layer forming step by the secondary polishing step.

(Final cleaning / inspection process)
1-3 (i) shows the final cleaning / inspection process. In the final cleaning, dirt such as the used abrasive is removed in the series of steps described above. For the cleaning, a method such as chemical cleaning with a detergent (chemical) using ultrasonic waves can be used.
In the inspection process, for example, the surface of the glass substrate 10 is inspected for scratches or distortions by an optical inspection device using a laser.

(Packing process)
Fig. 1-3 (j) shows the packing process. In the packing process, the glass substrate 10 that has passed the quality standard determined in the above-described inspection process is packed, and a package 90 of the glass substrate 10 is obtained. The package 90 is transported to a location where a magnetic recording medium (magnetic disk) is manufactured. This packing is performed in order to suppress adhesion of foreign matters such as dust and surface state changes to the glass substrate 10 during transportation.

  Here, in the polishing step, the polishing machine 50 polishes both surfaces of the glass substrate 10 simultaneously. However, when polishing is performed, there may be a difference in the polishing amount between one surface and the other surface. That is, when one surface is polished more preferentially than the other surface, the allowance for one surface may be large, but the allowance for the other surface may be small.

  Such a phenomenon that a difference in polishing amount between one surface and the other surface of the glass substrate 10 can be suppressed by adjusting the polishing conditions of the polishing machine 50. Therefore, it is necessary to adjust the polishing conditions of the polishing machine 50 appropriately.

In the present embodiment, in order to solve the above problem, the polishing conditions of the polishing machine 50 are adjusted by the following method.
FIG. 5A is a perspective view illustrating a first example of the measurement substrate 100 used for adjusting the polishing conditions of the polishing machine 50. FIG. 5B is a Vb-Vb cross-sectional view of the measurement substrate 100 shown in FIG.

The measurement substrate 100 shown in FIGS. 5A to 5B is formed of the same material and the same shape as the glass substrate 10. That is, the measurement substrate 100 is made of the same glass material as that used for the glass substrate 10 and has a disk shape. And it has the opening 12 in the center. However, unlike the glass substrate 10, measurement grooves 103 are formed on both surfaces of the measurement substrate 100.
The measurement substrate 100 can be manufactured by etching (etching) the glass substrate 10 to form the measurement groove 103.

  Here, the measurement groove 103 is formed on the first surface 101 of the measurement substrate 100. The width (W) of the measurement groove 103 may be, for example, a rectangular shape in cross section, the width (W) may be 200 μm, the length (L) may be 1 mm, and the depth (H) may be 7 μm. The depth (H) is preferably changed as appropriate according to the polishing amount. In addition, the position where the measurement groove 103 is formed is not particularly limited, but in this embodiment, the measurement groove 103 is formed at an intermediate position between the opening 12 of the measurement substrate 100 and the outer periphery 13 which is the outermost peripheral portion of the glass substrate 100. To do.

FIG. 6 is a flowchart illustrating a procedure for adjusting the polishing conditions of the polishing machine 50 using the measurement substrate 100 shown in FIGS.
The outline of the procedure for adjusting the polishing conditions of the polishing machine 50 will be described below with reference to FIGS. 5 (a) to 5 (b) and FIG. In this embodiment, two measurement substrates 100 shown in FIGS. 5A to 5B are used. For convenience of explanation, the two measurement substrates 100 are referred to as a first measurement substrate 100a and a second measurement substrate 100b.

First, the first measurement substrate 100a is arranged in the polishing machine 50 so that the measurement groove 103 faces the side of the polishing machine 50 that polishes both sides of the first surface (step 101). That is, the first measurement substrate 100a is disposed on the polishing machine 50 with the first surface 101 of the first measurement substrate 100a facing the first surface of the polishing machine 50 on which the first surface is polished.
Next, the second measurement substrate 100b is placed on the polishing machine 50 so that the measurement groove 103 faces the side of the polishing machine 50 where the second surface is polished (step 102). In other words, the first measurement surface 100b of the second measurement substrate 100b is opposed to the polishing surface 50 by making the first surface 101 of the second measurement substrate 100b face the second surface opposite to the first surface of both surfaces of the polishing machine 50. To place. As a result, the measurement substrates 100a and 100b are arranged such that the first surfaces 101 are opposite to each other. In the present embodiment, the measurement substrates 100a and 100b are arranged in the hole 34 (see FIG. 3) of the holder 30 (see FIG. 3). At this time, the glass substrate 10 is disposed in the remaining locations other than the locations where the measurement substrates 100a and 100b are disposed.
Next, the first measurement substrate 100a and the second measurement substrate 100b arranged in the polishing machine 50 are polished by the polishing machine 50 (step 103). Then, the depth after polishing of the measurement groove 103 of the first measurement substrate 100a and the measurement groove 103 of the second measurement substrate 100b is measured (step 104). The depth of the measurement groove 103 can be measured by using, for example, a surface roughness meter.
Further, the difference between the polishing amount on the first surface of the polishing machine 50 and the polishing amount on the second surface is calculated from the measured depth of the measurement groove 103 (step 105).
Then, based on the calculated difference between the polishing amount on the first surface of the polishing machine 50 and the polishing amount on the second surface, the polishing conditions of the polishing machine 50 are adjusted so as to suppress the difference in the polishing amount (step) 106). The polishing conditions for adjustment include, for example, a change in polishing pressure applied to the glass substrate 10 during polishing, a change in the number of rotations of the lower surface plate 21a and the upper surface plate 21b, and the like.

Accordingly, the measurement substrates 100a and 100b can be polished under the same conditions as when the glass substrate 10 is actually polished by the polishing machine 50. At this time, since the measurement substrates 100a and 100b are made of the same material and the same shape as the glass substrate 10, the measurement substrates 100a and 100b and the glass substrate 10 can be regarded as being polished in the same manner. . Eventually, by measuring the depth of the polishing groove 103 of the measurement substrates 100a and 100b, the difference in polishing amount between both surfaces of the glass substrate 10 can be easily measured.
Furthermore, according to the present embodiment, by using two measurement substrates 100, when the glass substrate 10 is arranged in the polishing machine 50, the difference in polishing amount due to the difference in position can be measured simultaneously. Then, the polishing conditions of the polishing machine 50 can be adjusted so as to suppress the difference in the polishing amount due to the difference in the arrangement position.

In the measurement substrate 100 described above, the measurement groove is formed on one surface thereof, but the present invention is not limited to this.
FIG. 7A is a perspective view illustrating a second example of the measurement substrate 100 used for adjusting the polishing conditions of the polishing machine 50. FIG. 7B is a sectional view taken along the line VIIb-VIIb of the measurement substrate 100 shown in FIG.

  The measurement substrate 100 shown in FIGS. 7A to 7B is formed of the same material and the same shape as the glass substrate 10 like the measurement substrate 100 shown in FIGS. Yes. However, unlike the measurement substrate 100 shown in FIGS. 5A to 5B, in the measurement substrate 100 shown in FIGS. 7A and 7B, the measurement grooves are formed on both surfaces of the measurement substrate 100. ing. 7A and 7B, the measurement groove 103 is formed on the first surface 101 of the measurement substrate 100, and the measurement groove is also formed on the second surface 102 opposite to the first surface 101. 104 is formed.

  The width (W), length (L), and depth (H) of the measurement groove 104 can be formed in the same manner as the measurement groove 103. The measurement groove 104 is formed at the intermediate position between the opening 12 and the outer periphery 13 of the measurement substrate 100 in the same manner as the measurement groove 103. However, the measurement groove 103 is along the circumferential direction. It is preferable to form by shifting. When the depths of the measurement grooves 103 and 104, which will be described later, are measured, it is easier to form them when they are not formed at the same location.

FIG. 8 is a flowchart illustrating a procedure for adjusting the polishing conditions of the polishing machine 50 using the measurement substrate 100 shown in FIGS.
Hereinafter, an outline of a procedure for adjusting the polishing conditions of the polishing machine 50 will be described with reference to FIGS. 7A to 7B and FIG. 8. In this embodiment, two measurement substrates 100 shown in FIGS. 7A to 7B are used. For convenience of explanation, the two measurement substrates 100 are referred to as a first measurement substrate 100a and a second measurement substrate 100b.

  First, the measurement substrates 100a and 100b having the measurement grooves 103 and 104 formed on the surface are placed in the polishing machine 50 (step 201). In the present embodiment, the measurement substrates 100a and 100b are arranged in the hole 34 (see FIG. 3) of the holder 30 (see FIG. 3). At this time, the glass substrate 10 is disposed in the remaining locations other than the locations where the measurement substrates 100a and 100b are disposed. Next, both surfaces of the measurement substrates 100a and 100b arranged in the polishing machine 50 are simultaneously polished (step 202). Then, the depths of the measurement grooves 103 and 104 left on the polished measurement substrate 100 are measured (step 203). Further, a difference in polishing amount between both surfaces of the measurement substrates 100a and 100b is calculated from the measured depths of the measurement grooves 103 and 104 (step 204). Then, based on the calculated difference in polishing amount on both surfaces of the measurement substrates 100a and 100b, the polishing conditions of the polishing machine 50 are adjusted so as to suppress this difference in polishing amount (step 205).

  Thus, by measuring the depth of the measurement grooves 103 and 104 of the measurement substrate 100, the difference in the polishing amount due to the difference in the polishing amount on both surfaces of the glass substrate 10 and the position where the measurement substrate 100 is disposed can be measured. The polishing conditions of the polishing machine 50 can be adjusted so as to suppress the difference between the polishing amounts. Further, according to the present embodiment, since the measurement grooves 103 and 104 are formed on both surfaces of the measurement substrate 100, when the glass substrate 10 is disposed in the polishing machine 50 due to the difference in polishing amount on both surfaces of the glass substrate 10. The difference in the polishing amount due to the difference in position can be measured more clearly.

The adjustment of the polishing conditions of the polishing machine 50 by the above-described method is more effective in the secondary polishing process than in the primary polishing process.
That is, the polishing amount in the primary polishing step is, for example, 30 μm. On the other hand, the polishing amount in the secondary polishing step is, for example, 4 μm. In this case, since the polishing amount is large in the primary polishing step, the difference in the polishing amount on both surfaces of the glass substrate 10 can be measured by other methods.

FIG. 9 is a diagram illustrating another example of measuring a difference in polishing amount between both surfaces of the glass substrate 10.
In FIG. 9, the vicinity of the outer periphery 13 of the glass substrate 10 is illustrated. Here, in the outer periphery 13, the surface 10c is a chamfered portion in the above-described inner and outer periphery grinding process. Here, a portion indicated by a dotted line shows a cross section of the glass substrate 10 before the primary polishing step. Moreover, the part shown with the continuous line has shown the cross section of the glass substrate 10 after a primary polishing process.

  Here, the difference in the polishing amount between the first surface 10a and the second surface 10b of the glass substrate 10 can be measured from the shape of the surface 10c which is a chamfered portion. That is, in FIG. 9, the first surface 10a and the second surface 10c of the glass substrate 10 and the second surface 10b of the glass substrate 10 and the second surface 10b and the surface 10c of the glass substrate 10 intersect as a reference. The polishing amount of the surface 10b can be calculated. Taking the case of calculating the polishing amount of the first surface 10a as an example, more specifically, first, the width of the surface 10c viewed from the first surface 10a of the glass substrate 10 before the primary polishing step is “a”. It is. In addition, the width of the surface 10c viewed from the first surface 10a of the glass substrate 10 after the primary polishing step is “b”. Then, by taking this difference, the width “c” of the surface 10c polished in the primary polishing process viewed from the first surface 10a is obtained (c = a−b). Since the angle between the first surface 10a and the surface 10c is known in advance, the polishing amount of the first surface 10a can be calculated from the value of “c”. And the difference of the grinding | polishing amount in both surfaces of the glass substrate 10 is computable by calculating the grinding | polishing amount of the 2nd surface 10b by the same method. In this method, the glass substrate 10 can be used as it is as the measurement substrate.

  On the other hand, in the secondary polishing step, as described above, the polishing amount is very small. Therefore, it is difficult to accurately calculate the difference between the polishing amounts on both surfaces of the glass substrate 10 by the method shown in FIG. Therefore, the method described above with reference to FIGS. 5 to 8 becomes more effective. That is, in the primary polishing step, the polishing conditions of the polishing machine 50 are adjusted using a measurement substrate in which no measurement groove is formed on the surface, and in the secondary polishing step, the measurement substrate 100 in which the measurement groove is formed on the surface is used. Thus, the polishing conditions of the polishing machine 50 can be adjusted.

  In addition, when providing a reinforcement layer, it is necessary to remove a reinforcement layer at a grinding | polishing process as mentioned above. However, when polishing is performed, if there is a difference in the polishing amount between one surface and the other surface, a part of the reinforcing layer provided on the other surface may not be removed and may remain. In this case, the balance of stress is lost between one surface of the glass substrate 10 and the other surface, and the glass substrate 10 is likely to warp. Therefore, when providing a reinforcement layer, it is preferable to adjust the polishing conditions so as to remove the reinforcement layer.

DESCRIPTION OF SYMBOLS 10 ... Glass substrate, 50 ... Polishing machine, 100 ... Measurement substrate, 101 ... First surface, 102 ... Second surface, 103, 104 ... Measurement groove

Claims (7)

A method of manufacturing a disk-shaped substrate, wherein a first surface and a second surface of a plurality of disk-shaped substrates are simultaneously polished using a polishing apparatus,
A first measurement substrate having a measurement groove formed on a surface thereof is disposed in the polishing apparatus such that the measurement groove faces the side of the polishing apparatus on which the first surface is polished;
A second measurement substrate having a measurement groove formed on a surface thereof is disposed in the polishing apparatus so that the measurement groove faces the side of the polishing apparatus on which the second surface is polished;
Polishing the first measurement substrate and the second measurement substrate disposed in the polishing apparatus by the polishing apparatus,
The depth after polishing of the measurement groove of the first measurement substrate and the measurement groove of the second measurement substrate is measured, and the polishing condition of both surfaces of the disk-shaped substrate by the polishing apparatus is adjusted. A method for manufacturing a disk-shaped substrate. The measurement groove of the first measurement substrate and the measurement groove of the second measurement substrate are formed on the first surface of the first measurement substrate and the second measurement substrate,
The first measurement substrate is disposed in the polishing apparatus with the first surface of the first measurement substrate facing the first surface of the both surfaces of the polishing apparatus facing the first surface,
The second measurement substrate is polished by causing the first surface of the second measurement substrate to face the second surface of the polishing apparatus opposite to the first surface that is opposite to the first surface. 3. The method for manufacturing a disk-shaped substrate according to claim 1, wherein the disk-shaped substrate is disposed in an apparatus.   The polishing condition is adjusted by measuring the polishing amount on the first surface of the polishing apparatus calculated by measuring the depth of the measurement groove of the first measurement substrate and the depth of the measurement groove of the second measurement substrate. The method for manufacturing a disk-shaped substrate according to claim 2, wherein adjustment is performed so as to suppress a difference between the polishing amount on the second surface and the polishing amount on the second surface.   The measurement groove of the first measurement board and the measurement groove of the second measurement board are formed on both surfaces of the first measurement board and the second measurement board, respectively. 2. A method for producing a disk-shaped substrate according to 2.   The adjustment of the polishing condition suppresses the difference in the polishing amount of the polishing apparatus calculated by measuring the depth of the measurement groove of the first measurement substrate and the depth of the measurement groove of the second measurement substrate. It adjusts so that it may carry out, The manufacturing method of the disk shaped board | substrate of Claim 4 characterized by the above-mentioned. The polishing of the disc-shaped substrate is performed by a pre-polishing step for rough polishing the disc-shaped substrate and a post-polishing step for performing precise polishing of the disc-shaped substrate,
In the pre-polishing step, the polishing conditions are adjusted using a measurement substrate in which the measurement groove is not formed on the surface,
6. The polishing process according to claim 1, wherein, in the subsequent polishing step, the polishing conditions are adjusted using the first measurement substrate and the second measurement substrate having the measurement groove formed on a surface thereof. A method for producing a disk-shaped substrate according to claim 1. The disk-shaped substrate has a compressive stress layer formed on both sides,
The method for manufacturing a disk-shaped substrate according to any one of claims 1 to 6, wherein the polishing condition is adjusted so as to remove the compressive stress layer.

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