JP2015164084A - Magnetic disk substrate manufacturing method and polishing processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk substrate manufacturing method and a polishing processing apparatus, capable of simultaneously polishing many disk-shaped substrates at a time of polishing principal surfaces of the substrates between an upper surface plate and a lower surface plate, and ensuring less polishing irregularities and less irregularities in plate thickness after polishing.SOLUTION: In the polishing processing, a carrier plate layered body formed by building up a plurality of internal carriers (carrier plates) each holding substrates with a polishing plate including polishing surfaces formed on both sides put between the carrier plates is caused to revolve together with the polishing plate around rotation center axes of an upper surface plate and a lower surface plate while sliding the polishing plate and the substrates relatively, whereby two principal surfaces of each of the substrates are simultaneously polished using a polishing surface provided on the upper surface plate, a polishing surface provided on the lower surface plate, and the polishing surfaces of the polishing plate.

Description

  The present invention relates to a method for manufacturing a magnetic disk substrate including a polishing process for polishing a main surface of a disk-shaped substrate between an upper surface plate and a lower surface plate, and a polishing apparatus.

  Conventionally, a glass substrate has been suitably used for a magnetic disk used as one of information recording media. Today, in response to a request for an increase in storage capacity in a hard disk drive device, the density of magnetic recording has been increased. Along with this, the magnetic recording information area is miniaturized by extremely shortening the flying distance from the magnetic recording surface of the magnetic head. It is preferable that the size and shape of the glass substrate used for such a magnetic disk be manufactured with high accuracy as intended.

  The surface of the glass substrate is polished in order to manufacture the glass substrate with high accuracy in size and shape. In polishing a glass substrate, a planetary gear mechanism polishing apparatus has been conventionally used to polish a glass substrate sandwiched between two surface plates. In order to polish more glass substrates in a short time, a polishing apparatus having a lower surface plate, an intermediate surface plate, and an upper surface plate, each surface plate being configured to be driven to rotate relative to each other is known. (Patent Document 1).

  In the polishing apparatus, a polishing tool is provided on the upper surface of the lower surface plate, a polishing tool is provided on the upper surface and the lower surface of the middle surface plate, and a polishing tool is provided on the lower surface of the upper surface plate. A plurality of carriers provided with receiving holes for receiving glass substrates are arranged on the lower surface plate polishing tool, and a plurality of similar carriers are also arranged on the middle surface plate polishing tool. Of the carriers arranged in two stages on the top and bottom, the lower carrier meshes with the sun gear and the upper carrier meshes with the sun gear to move the glass substrate horizontally, so that both surfaces of the glass substrate move simultaneously. Polished.

JP 2000-127032 A

However, in the above-described polishing apparatus, uneven polishing was observed on the glass substrate polished at the same time, and variations in the plate thickness after polishing were observed. This is thought to be due to the fact that the parallelism between the three surface plates decreases, and the pressure applied to the glass substrate during polishing varies depending on the location and is not uniform. In the above polishing apparatus, since a lower surface plate, a middle surface plate, and an upper surface plate are used, it is extremely difficult to maintain parallelism between the surface plates.
Such a problem similarly occurs not only on a glass substrate but also on a metal substrate such as an aluminum alloy substrate to be polished.

  Therefore, the present invention can polish a large number of substrates at the same time when polishing the main surface of a disk-shaped substrate between an upper surface plate and a lower surface plate. It is an object of the present invention to provide a method of manufacturing a magnetic disk substrate including a polishing process and a polishing apparatus that hardly cause variations in plate thickness afterwards.

  In a conventional polishing apparatus having three surface plates, the outer peripheral portion of the surface plate is more easily bent downward due to its own weight than the center portion supported by the rotating shaft, and the parallelism between the surface plates is reduced. easy. For this reason, variation in plate thickness and polishing unevenness are likely to occur. For this reason, the inventor of the present application is a polishing method using two surface plates, an upper surface plate and a lower surface plate, which can polish a large number of substrates at the same time, and the variation in thickness and polishing of the substrate thickness. As a result of intensive studies, the inventors have invented a polishing method capable of reducing unevenness as compared with the conventional method.

One aspect of the present invention is a method of manufacturing a magnetic disk substrate by polishing a main surface of a disk-shaped substrate between an upper surface plate and a lower surface plate having a rotation center axis.
In the polishing process, a carrier plate laminate formed by stacking the carrier plates in multiple stages with a polishing plate having polishing surfaces formed on both sides between a plurality of carrier plates holding a plurality of substrates, By relatively sliding the polishing plate and the substrate between the upper surface plate and the lower surface plate while revolving together with the polishing plate around the rotation center axis of the upper surface plate and the lower surface plate The main surfaces on both sides of the substrate are simultaneously polished using the polishing surface provided on the upper platen, the polishing surface provided on the lower platen, and the polishing surface of the polishing plate.

  At that time, the main surfaces on both sides of the substrate are polished using an annular member that fixes one outer side of the plurality of carrier plates and the polishing plate of the carrier plate laminate, and the annular member is rotated to the central axis of rotation. It is preferable that at least one of the plurality of carrier plates and the polishing plate is rotated by being rotated while revolving around.

  In the polishing process, it is preferable that the polishing plate and the substrate are relatively slid by rotating the plurality of carrier plates while revolving around the rotation center axis.

  Alternatively, during the polishing process, it is also preferable that the polishing plate and the substrate are relatively slid by rotating the polishing plate while revolving around the rotation center axis.

  The polishing plate is preferably provided with a through-hole through which the liquid passes in order to flow the liquid supplied to the main surface of the substrate from the upper side to the lower side.

Another embodiment of the present invention is a polishing apparatus for polishing a main surface of a disk-shaped substrate. The polishing processing apparatus
An upper surface plate and a lower surface plate having a rotation center axis provided with a polishing surface for sandwiching the substrate from the main surface sides on both sides of the plurality of substrates,
Holding a plurality of substrates, a plurality of carrier plates provided in multiple stages between the upper surface plate and the lower surface plate, and
A polishing plate provided between the carrier plates stacked in multiple stages, the polishing surfaces having polishing surfaces formed on both sides;
A carrier plate laminate formed by stacking the carrier plates in multiple stages with the polishing plate sandwiched between a plurality of the carrier plates, the upper surface plate and the lower surface plate between the upper surface plate and the lower surface plate And a moving mechanism for relatively sliding the polishing plate and the substrate while revolving together with the polishing plate around a rotation center axis.

  The polishing apparatus further includes an annular member that fixes one of the plurality of carrier plates and the polishing plate of the carrier plate laminate, and rotates while rotating the annular member around the rotation center axis. It is preferable that at least one of the plurality of carrier plates and the polishing plate is rotated by performing the above.

In addition, the carrier plate and the annular member include an engaging portion that meshes with each other and fixes the carrier plate to the annular member in the circumferential direction of the annular member,
Preferably, the annular member rotates while revolving around the rotation center axis, and the carrier plate rotates while revolving around the rotation center axes of the upper surface plate and the lower surface plate.

  The polishing plate and the annular member include an engaging portion that meshes with each other and fixes the polishing plate with respect to the annular member in a circumferential direction of the annular member. It is also preferable that the polishing plate rotates while revolving around, and the polishing plate rotates while revolving around the rotation center axis.

  According to the above-described method for manufacturing a magnetic disk substrate and polishing apparatus, a large number of substrates can be polished simultaneously, so that polishing unevenness after polishing is smaller and variation in plate thickness after polishing is smaller than in the past. A substrate can be obtained.

It is a figure which shows the external appearance shape of the grinding | polishing processing apparatus of one form used for the manufacturing method of the glass substrate for magnetic discs of this embodiment. It is an enlarged view of the cross section of the principal part of the grinding | polishing processing apparatus shown in FIG. (A), (b) is a figure explaining the example of a movement of the annular member and internal carrier in the grinding | polishing processing apparatus shown in FIG. It is a figure which shows the external appearance shape of the grinding | polishing processing apparatus of another form used for the manufacturing method of the glass substrate for magnetic discs of this embodiment. It is an enlarged view of the cross section of the principal part of the grinding | polishing processing apparatus shown in FIG. (A), (b) is a figure explaining the example of the movement of the annular member and internal carrier in the grinding | polishing processing apparatus shown in FIG. It is a figure explaining the example of the surface of the grinding | polishing board used for the grinding | polishing processing apparatus of this embodiment.

  Hereinafter, a method for manufacturing a magnetic disk substrate and a polishing apparatus according to the present invention will be described in detail. In the present specification, the polishing treatment includes grinding of the glass substrate for cutting the glass main surface in order to adjust the shape of the glass substrate to a predetermined shape, and polishing treatment for reducing surface irregularities on the glass main surface after grinding. In the embodiment described below, a glass substrate is used as a substrate to be polished, but it can also be applied to a metal substrate such as an aluminum alloy in addition to the glass substrate.

(Polishing apparatus 10)
One embodiment of a glass substrate polishing apparatus for performing a polishing process performed in the glass substrate manufacturing method of the present embodiment will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a polishing apparatus. FIG. 2 is an enlarged view of a cross section of a main part of the polishing processing apparatus. FIGS. 3A and 3B are diagrams illustrating an example of the movement of the carrier plate that holds the annular member and the glass substrate.

  As shown in FIG. 1, the polishing apparatus 10 has a pair of upper and lower surface plates, that is, an upper surface plate 50 and a lower surface plate 60. The upper surface plate 50 and the lower surface plate 60 have a rotation center axis, and sandwich the plurality of glass substrates G from the glass main surface sides on both sides of the glass substrate G. On the lower surface of the upper surface plate 50 and the upper surface of the lower surface plate 60, a polishing surface 12, for example, a surface of a polishing pad, for polishing the glass substrate G is provided. Each surface plate moves relative to the glass substrate G by moving the upper surface plate 50 or the lower surface plate 60 or both of them so as to rotate around the rotation center axis. In the polishing apparatus 10, the rotation direction and the rotation speed of the upper surface plate 50 and the lower surface plate 60 may be the same, or may be configured to be freely set separately. Therefore, the rotation direction and the rotation speed may be the same or different. Thereby, both main surfaces of the glass substrate G can slide with a grinding | polishing surface and can grind | polish. Here, a carrier plate laminate in which carrier plates holding a plurality of glass substrates G are laminated in multiple stages rotates around the central axis. Specifically, in addition to the upper surface plate 50 and the lower surface plate 60, the polishing apparatus 10 includes carrier plates 30a and 30b, a polishing plate 32, an annular member 34, a sun gear 61, an internal gear 62, Have

Each of the carrier plates 30 a and 30 b is a circular plate that holds a plurality of glass substrates G and is provided in multiple stages between the upper surface plate 50 and the lower surface plate 60. The carrier plates 30a and 30b are provided with a plurality of holding holes for holding a plurality of glass substrates G.
The polishing plate 32 is provided so as to be sandwiched between carrier plates 30a and 30b stacked in multiple stages. A polishing surface 36, for example, a polishing pad surface, is formed on both sides. On the outer peripheral end surfaces of the carrier plates 30a and 30b, engagement convex portions are formed that engage with engagement concave portions formed on an inner peripheral wall surface of the annular member 34, which will be described later, and fix the carrier plates 30a and 30b to the annular member 34. ing. Specifically, the fixing by the engaging concave portion and the engaging convex portion is fixing in the circumferential direction of the annular member 34. When the carrier plates 30 a and 30 b are fixed to the annular member 34, the carrier plates 30 a and 30 b may be fixed to the upper end surface or the lower end surface of the annular member 34 in addition to the case of fixing to the inner peripheral surface of the annular member 34.

  The annular member 34 has an annular shape and is provided between the upper surface plate 50 and the lower surface plate 60. On the inner peripheral wall surface of the annular member 34, an engagement recess is formed that engages with the engagement protrusions on the outer peripheral end surfaces of the carrier plates 30 a and 30 b, and the carrier plates 30 a and 30 b are in relation to the annular member 34. It is fixed in the circumferential direction. The engaging convex portion and the engaging concave portion are collectively referred to as an engaging portion. Fixing in the circumferential direction means that no relative movement or displacement occurs between the carrier plates 30a and 30b and the annular member 34 in the circumferential direction. Thereby, when the annular member 34 rotates, the internal carriers 30a and 30b also rotate. On the other hand, a gear that meshes with the sun gear 61 and the internal gear 62 is formed on the outer peripheral wall surface of the annular member 34. The sun gear 61 and the internal gear 62 slidably move the polishing plate 32 and the glass substrate G while revolving the carrier plate laminate around the rotation center axis of the upper surface plate 50 and the lower surface plate 60 together with the polishing plate 32. It is a moving mechanism to move. The carrier plate laminate is formed by laminating a plurality of carrier plates in multiple stages with the polishing plate 32 interposed therebetween.

  Since the sun gear 61 and the internal gear 62 are rotated by a drive source such as a motor (not shown), the annular member 34 and the carrier plates 30a and 30b are rotated as shown in FIG. As shown, it revolves around the rotation center axis of the upper surface plate 50 and the lower surface plate 60 while rotating. Since the polishing plate 32 is not fixed to the annular member 34 in the circumferential direction, the polishing plate 32 does not rotate in conjunction with the sun gear 61 and the internal gear 62, as shown in FIG. Revolve.

  As described above, in this embodiment, the internal carriers 30a and 30b are stacked in multiple stages with the polishing plates 32 having the polishing surfaces 36 formed on both sides between the carrier plates 30a and 30b holding the glass substrate G. The glass substrate G is polished between the upper surface plate 50 and the lower surface plate 60 together with the polishing plate 32 while revolving the carrier plate laminate formed by the process around the rotation center axis of the upper surface plate 50 and the lower surface plate 60. The glass main surfaces on both sides of the glass substrate G are simultaneously formed using the polishing surface provided on the upper surface plate 50, the polishing surface provided on the lower surface plate 60, and the polishing surface of the polishing plate 32. Polish. In the present embodiment, a polishing plate 32 having substantially the same size as the carrier plates 30a and 30b is used without providing an intermediate surface plate in addition to the upper surface plate 50 and the lower surface plate 60. For this reason, it is not necessary to adjust the parallelism between the three surface plates as in the prior art, and only the parallelism of the upper surface plate 50 and the lower surface plate 60 needs to be adjusted. A glass substrate with small unevenness and small variation in plate thickness after polishing can be obtained. In addition, since the glass main surfaces on both sides of the glass substrate G are polished by overlapping the carrier plates 30a and 30b in multiple stages, a large number of glass substrates can be polished simultaneously.

Further, in the present embodiment, the carrier plate laminate is configured such that the carrier plates 30a and 30b of the carrier plate laminate are fixed to the annular member 34 in the circumferential direction of the annular member 34 using the engaging portion during the polishing process. Are arranged surrounded by the inner peripheral surface of the annular member 34. Then, at least the carrier plates 30a and 30b are rotated by rotating the annular member 34 while revolving around the rotation center axes of the upper surface plate 50 and the lower surface plate 60, that is, by causing the planetary gear mechanism to move. Thus, the glass substrate G and the polishing surfaces of the upper surface plate 50, the lower surface plate 60, and the polishing plate 32 slide relative to each other. For this reason, the grinding | polishing process of the glass plate G can be performed efficiently.
In particular, during the polishing process, the carrier plates 30a and 30b are rotated while revolving around the rotation center axes of the upper surface plate 50 and the lower surface plate 60, thereby causing the polishing plate 32 and the glass substrate G to slide relative to each other. Therefore, the polishing process of the glass plate G by the polishing surface 36 can be performed efficiently.

  In the present embodiment, the carrier plate laminate is revolved around the rotation center axes of the upper surface plate 50 and the lower surface plate 60 by using the annular member 34 that surrounds and engages the carrier plate laminate. 34 need not be used. At least the carrier plate laminate formed by stacking the carrier plates 30a and 30b with the polishing plate 32 sandwiched between the carrier plates 30a and 30b holding the glass substrate G and revolving around the rotation center axis is made of glass. What is necessary is just to slide the board | substrate G and the grinding | polishing board 32 relatively. For example, the carrier plates 30a and 30b may include a sun gear 61 and a gear meshing with the internal gear 62 on the outer end surface.

(Polishing apparatus 100)
Another embodiment of the glass substrate polishing apparatus for performing the polishing process performed in the glass substrate manufacturing method of the present embodiment will be described with reference to FIGS. FIG. 4 is an exploded perspective view of the polishing processing apparatus. FIG. 5 is an enlarged view of a cross section of a main part of the polishing processing apparatus. FIGS. 6A and 6B are diagrams illustrating an example of the movement of the carrier plate that holds the annular member and the glass substrate.

  As shown in FIG. 4, the polishing apparatus 100 has a pair of upper and lower surface plates, that is, an upper surface plate 150 and a lower surface plate 160. Similar to the upper surface plate 50 and the lower surface plate 60 of the polishing processing apparatus 10, the upper surface plate 150 and the lower surface plate 160 have a rotation center axis, and the glass substrate G from the glass main surface side on both sides of the glass substrate G. Between. A polishing surface 112 for polishing the glass substrate G, for example, a surface of a polishing pad, is provided on the lower surface of the upper surface plate 50 and the upper surface of the lower surface plate 60. Each surface plate moves relative to the glass substrate G by performing a moving operation so that either one or both of the upper surface plate 150 and the lower surface plate 160 rotate around the rotation center axis. In the polishing apparatus 100, the rotation direction and the number of rotations of the upper surface plate 150 and the lower surface plate 160 may be the same, or may be configured to be freely set separately. Therefore, the rotation direction and the rotation speed may be the same or different. Thereby, both main surfaces of the glass substrate G can be polished. Here, a carrier plate laminate in which carrier plates holding a plurality of glass substrates G are laminated in multiple stages rotates around the central axis. Specifically, in addition to the upper surface plate 150 and the lower surface plate 160, the polishing apparatus 100 includes carrier plates 130a and 130b, a polishing plate 132, an annular member 134, a sun gear 161, an internal gear 162, Have Polishing surfaces 136 are provided on both surfaces of the polishing plate 132.

When the polishing apparatus 100 is compared with the polishing apparatus 10, the outer peripheral end surface of the polishing plate 132 is provided with an engaging convex portion that meshes with an engaging concave portion provided on the inner peripheral wall surface of the annular member 134. Is fixed to the annular member 134 in the circumferential direction of the annular member 134.
Fixing in the circumferential direction means that no relative movement or displacement occurs between the carrier plates 130a and 130b and the annular member 134 in the circumferential direction. When the carrier plates 130 a and 130 b are fixed to the annular member 134, the carrier plates 130 a and 130 b may be fixed to the upper end surface or the lower end surface of the annular member 134 in addition to fixing to the inner peripheral surface of the annular member 134. The engaging convex portion and the engaging concave portion are collectively referred to as an engaging portion. Thereby, when the annular member 134 rotates, the carrier plates 130a and 130b rotate. The outer peripheral end faces of the carrier plates 130a and 130b are not provided with gears that mesh with the gears provided on the inner peripheral wall surface of the annular member 134. Since the configuration other than this is the same as that of the polishing apparatus 10, description thereof is omitted.

In the polishing apparatus 100, the carrier plate laminate is an inner peripheral surface of the annular member 134 so that the polishing plate 132 is fixed to the annular member 134 in the circumferential direction of the annular member 34 using the engaging portion during the polishing process. Surrounded by. Then, at least the polishing plate 132 is rotated by rotating the annular member 134 while revolving around the rotation center axis of the upper surface plate 150 and the lower surface plate 160, that is, by causing the planetary gear mechanism to move. Thus, the glass substrate G and the polishing surfaces of the upper surface plate 150, the lower surface plate 160, and the polishing plate 32 slide relative to each other. For this reason, the grinding | polishing process of the glass plate G can be performed efficiently.
Since the sun gear 161 and the internal gear 162 are rotated by a drive source such as a motor (not shown), the annular member 134 and the polishing plate 132 are rotated by the sun gear 161 and the internal gear 162 as shown in FIG. In addition, it revolves around the rotation center axis of the upper surface plate 150 and the lower surface plate 160 while rotating. Since the carrier plates 130a and 130b are not fixed in the circumferential direction with respect to the annular member 134, the carrier plates 130a and 130b rotate in conjunction with the sun gear 161 and the internal gear 162 as shown in FIG. Revolution without doing. Accordingly, since the polishing plate 132 and the glass substrate G are relatively slid, the polishing treatment of the glass plate G by the polishing surface 36 can be performed efficiently.

  During the polishing process, liquid such as polishing slurry or coolant flows from the upper surface plate 50, 150 between the glass main surface of the glass substrate G and the polishing surface, and is supplied from the upper side to the lower side. When 32 and 132 are provided, it becomes difficult for liquid such as polishing slurry or coolant to be supplied to the lower glass substrate. Therefore, as shown in FIG. 7, the polishing plates 32 and 132 have central holes 32 a and 132 a that are through-holes that allow the liquid supplied to the glass substrate to flow from the upper direction to the lower direction and the radial direction. It is preferable to provide hole rows 32b and 132b, which are rows of through holes extending in a row. FIG. 7 is a view for explaining an example of the surface of the polishing plate used in the polishing apparatus of this embodiment. In this case, as shown in FIG. 7, it is preferable to provide polishing surfaces 36 and 136 between adjacent hole rows 32b and 132b on the circumference.

In the present embodiment, a carrier plate laminate formed by stacking internal carriers 130a and 130b in multiple stages with a polishing plate 132 sandwiched between carrier plates 130a and 130b holding a glass substrate G is used as an upper surface plate 150. The glass plate G and the polishing plate 132 are relatively slid between the lower platen 160 and the polishing plate 132 while revolving around the rotation center axis of the upper platen 150 and the lower platen 160. The glass main surfaces on both sides of the glass substrate G are simultaneously polished using the polishing surface provided on 150, the polishing surface provided on the lower surface plate 160, and the polishing surface of the polishing plate 132. Also in this embodiment, the polishing plate 132 having substantially the same size as the carrier plates 130a and 130b is used without providing the middle surface plate in addition to the upper surface plate 150 and the lower surface plate 160. Therefore, unlike the prior art, it is not necessary to adjust the parallelism between the three surface plates, and only the parallelism of the upper surface plate 150 and the lower surface plate 160 needs to be adjusted. A glass substrate with small unevenness and small variation in plate thickness after polishing can be obtained. Further, since the glass main surfaces on both sides of the glass substrate G are polished by overlapping the carrier plates 130a and 130b in multiple stages, a large number of glass substrates can be polished simultaneously.
In any of the polishing processing apparatuses 10 and 100, when used for grinding a glass substrate that cuts the glass main surface, the surfaces of the upper surface plates 50 and 150 and the lower surface plates 60 and 160 and the surfaces of the polishing plates 32 and 132 are as follows. A pad or cast iron surface with fixed abrasive is used. When using fixed abrasive grains, for example, a grindstone in which diamond abrasive grains are bonded with a resin is used. In the above grinding, grinding is performed while supplying a polishing slurry containing a coolant such as a coolant and free abrasive grains to the glass substrate.

(Description of manufacturing method of glass substrate for magnetic disk)
In the manufacturing method of the present embodiment, first, a glass blank that is a material for a plate-shaped magnetic disk glass substrate having a pair of main surfaces is formed. Next, the molded glass blank is machined. The machining process includes an annular shape (ring shape) machining process, an end face polishing process, a main surface grinding process, and a main surface polishing process. Specifically, the produced glass blank is processed into an annular shape (ring shape). Thereby, a glass substrate is obtained. Further, shape processing is performed on the glass substrate. Next, end-face polishing is performed on the circular glass substrate that has been processed into a shape. Grinding is performed on the glass substrate that has been subjected to end face polishing. Next, the main surface of the glass substrate is polished. The glass substrate for magnetic disks is obtained through the above processing. Hereinafter, each process will be described in detail. Note that grinding may not be performed. Further, the order of the processes described above may be changed as appropriate.

(A) Molding of glass blank In the molding of a glass blank, for example, a press molding method can be used. A circular glass blank can be obtained by the press molding method. Furthermore, it can manufacture using well-known manufacturing methods, such as a downdraw method, a redraw method, and a fusion method. A disk-shaped glass substrate serving as a base of the magnetic disk glass substrate can be obtained by appropriately performing shape processing on the plate-shaped glass blanks produced by these known production methods.

(B) Annular shape processing After the press forming process, the formed glass blank is made into an annular (ring shape) glass substrate of a predetermined size by a method such as a known core drill or scribe.

(C) Shape processing processing Next, the shape processing processing will be described. The shape processing treatment includes chamfering processing (chamfering processing of the outer peripheral side end surface and the inner end surface) to the end portion of the glass substrate after the annular shape processing processing. The chamfering is performed with a diamond grindstone or the like on the outer peripheral side end face and the inner end face of the glass substrate after the circular shape processing. A glass substrate having a predetermined shape is generated by this shape processing. The chamfering inclination angle is, for example, 40 to 50 degrees with respect to the main surface, and is preferably about 45 degrees.

(D) End Surface Polishing Process Next, the end surface polishing process will be described. In the end surface polishing, mirror finishing is performed by brush polishing on the inner end surface and the outer peripheral side end surface of the glass substrate. At this time, an abrasive slurry containing fine particles such as cerium oxide as free abrasive grains is used. By polishing the end surface, removing contamination such as contamination and scratches on the end surface of the glass substrate will prevent the occurrence of thermal asperity failure and cause corrosion such as sodium and potassium. The occurrence of ion precipitation can be prevented.

(E) Grinding process In the grinding process, grinding is performed on the main surface of the glass substrate using a double-sided grinding apparatus having a planetary gear mechanism. As the double-side grinding apparatus, an apparatus having the same configuration as the polishing apparatus shown in FIG. 1 or 4 may be used. Specifically, the outer peripheral side end surface of the glass substrate generated from the glass blank is ground on the main surfaces on both sides of the glass substrate while holding the glass substrate in the holding hole provided in the holding member of the double-side grinding apparatus. . Grinding may be performed using loose abrasive grains or may be performed using fixed abrasive grains. In this case, the grinding process is performed using the polishing apparatuses 10 and 100 while applying a grinding liquid or the like to the glass substrate.

(F) Polishing treatment Next, the main surface of the ground glass substrate is polished. For polishing, the main surface is mirror-polished by removing scratches and distortions remaining on the main surface of the glass, or adjusting fine surface irregularities (micro-waveness, roughness). In the polishing process, the glass substrate is polished using a polishing apparatus 10 or 100 shown in FIG. 1 or 4 while applying a polishing slurry containing loose abrasive grains. By carrying out the polishing treatment, the roughness (Ra) of the main surface is reduced and the micro-waveness of the main surface is reduced. In this way, the polished glass substrate is cleaned to become a magnetic disk glass substrate. The polishing process may include two types of polishing: a first polishing and a second polishing performed after the first polishing in order to perform the polishing more precisely. In this case, the first polishing removes scratches and distortions remaining on the glass main surface or adjusts minute surface irregularities. In the second polishing, the glass main surface is mirror-polished. The second polishing may not be performed depending on circumstances.
Note that a chemical strengthening process may be performed between the polishing process and the grinding process, or between the first polishing and the second polishing.

  The method for manufacturing a magnetic disk substrate and the polishing apparatus of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention. Of course, improvements and changes may be made.

10, 110 Polishing processing device 12, 36 Polishing surface 30a, 30b, 130a, 130b Carrier plate 32, 132 Polishing plate 34, 134 Annular member 50, 150 Upper surface plate 60, 160 Lower surface plate 61, 161 Inside sun gears 62, 162 gear

Claims (9)

A method of manufacturing a magnetic disk substrate by polishing a main surface of a disk-shaped substrate between an upper surface plate and a lower surface plate having a rotation center axis,
In the polishing process, a carrier plate laminate formed by stacking the carrier plates in multiple stages with a polishing plate having polishing surfaces formed on both sides between a plurality of carrier plates holding a plurality of substrates, By relatively sliding the polishing plate and the substrate between the upper surface plate and the lower surface plate while revolving together with the polishing plate around the rotation center axis of the upper surface plate and the lower surface plate The main surface on both sides of the substrate is simultaneously polished using the polishing surface provided on the upper surface plate, the polishing surface provided on the lower surface plate, and the polishing surface of the polishing plate. A method for manufacturing a disk substrate.   A main surface on both sides of the substrate is polished using an annular member that fixes one outer side of the plurality of carrier plates and the polishing plate of the carrier plate laminate, and the annular member is disposed around the rotation center axis. The method for manufacturing a magnetic disk substrate according to claim 1, wherein at least one of the plurality of carrier plates and the polishing plate is rotated by rotating while revolving.   3. The magnetism according to claim 1, wherein the polishing plate and the substrate are relatively slid by rotating the plurality of carrier plates while revolving around the rotation center axis during the polishing process. 4. A method for manufacturing a disk substrate.   3. The magnetic disk according to claim 1, wherein the polishing plate and the substrate are slid relative to each other by rotating the polishing plate while revolving around the rotation center axis during the polishing process. A method for manufacturing a substrate.   The through-hole which allows the said liquid to pass through in order to flow the liquid supplied to the main surface of the said board | substrate from the upper direction to the downward direction is provided in the said grinding | polishing board. Of manufacturing a magnetic disk substrate. A polishing apparatus for polishing a main surface of a disk-shaped substrate,
An upper surface plate and a lower surface plate having a rotation center axis provided with a polishing surface for sandwiching the substrate from the main surface sides on both sides of the plurality of substrates,
Holding a plurality of substrates, a plurality of carrier plates provided in multiple stages between the upper surface plate and the lower surface plate, and
A polishing plate provided between the carrier plates stacked in multiple stages, the polishing surfaces having polishing surfaces formed on both sides;
A carrier plate laminate formed by stacking the carrier plates in multiple stages with the polishing plate sandwiched between a plurality of the carrier plates, the upper surface plate and the lower surface plate between the upper surface plate and the lower surface plate A polishing processing apparatus comprising: a moving mechanism that relatively slides the polishing plate and the substrate while revolving together with the polishing plate around a rotation center axis.   And further comprising an annular member for fixing one of the plurality of carrier plates and the polishing plate of the carrier plate laminate, and rotating the annular member while revolving around the rotation center axis. The polishing apparatus according to claim 6, wherein at least one of a plurality of carrier plates and the polishing plate is rotated. The carrier plate and the annular member include an engaging portion that meshes with each other and fixes the carrier plate to the annular member in the circumferential direction of the annular member;
The annular member rotates while revolving around the rotation center axis, and the carrier plate rotates while revolving around the rotation center axes of the upper surface plate and the lower surface plate. Polishing processing equipment.   The polishing plate and the annular member include an engaging portion that meshes with each other and fixes the polishing plate to the annular member in the circumferential direction of the annular member, and the annular member is arranged around the rotation center axis. The polishing apparatus according to claim 7, wherein the polishing plate rotates while revolving, and the polishing plate rotates while revolving around the rotation center axis.

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