CN108857869B

CN108857869B - Carrier for polishing or grinding treatment, method for producing same, and method for producing substrate

Info

Publication number: CN108857869B
Application number: CN201810660620.6A
Authority: CN
Inventors: 玉置将德; 中川裕树
Original assignee: Hoya Corp
Current assignee: Hoya Corp
Priority date: 2013-11-29
Filing date: 2014-12-01
Publication date: 2021-04-27
Anticipated expiration: 2034-12-01
Also published as: CN105792988B; WO2015080295A1; JP6577636B2; CN105792988A; JP2018196926A; CN108857869A; JP6371310B2; SG11201604185PA; JPWO2015080295A1

Abstract

Provided are a carrier for polishing or grinding treatment, a method for manufacturing the same, and a method for manufacturing a substrate. The carrier for polishing treatment is formed of a composite material including fibers oriented in at least one direction and a resin material, and has a holding hole for holding a disk-shaped substrate when a pair of main surfaces of the substrate is subjected to polishing treatment while the substrate is sandwiched by an upper flat plate and a lower flat plate. The holding hole has a 1 st wall portion formed on the periphery of the inner peripheral wall surface of the holding hole so that the substrate is in contact with the fibers in a state where the substrate is held by the holding hole, and a 2 nd wall portion formed so that the substrate is not in contact with the fibers in a state where the substrate is held by the holding hole. The 2 nd wall portion is formed in a portion of the inner peripheral wall surface that faces an orientation direction of the fibers including the one direction.

Description

Carrier for polishing or grinding treatment, method for producing same, and method for producing substrate

The present application is proposed as item 42 in the rules for carrying out the patent method, and is a divisional application of the invention patent application "carrier for polishing treatment, method for manufacturing carrier for polishing treatment, and method for manufacturing substrate for magnetic disk" with application date of 2014, 12/1 and application number of 201480064905.3 (international application number PCT/JP 2014/081800).

Technical Field

The present invention relates to a carrier for polishing or grinding treatment used for polishing treatment of a substrate, a method for manufacturing the carrier, and a method for manufacturing a substrate.

Background

As a magnetic disk used as one of information recording media, a glass substrate has been preferably used. With the demand for increasing the storage capacity of hard disk drives, magnetic recording is now being attempted to achieve higher densities. In this case, the floating distance of the magnetic head from the magnetic recording surface is made extremely short, and the magnetic recording information area is miniaturized. The size and shape of the glass substrate used for such a magnetic disk are preferably manufactured with high accuracy according to the object.

In order to manufacture the size and shape of the glass substrate with high precision, the surface of the glass substrate is ground and polished. In grinding and polishing of a glass substrate, a plate-shaped carrier for grinding or polishing is used, which holds a glass substrate to be ground or polished by being sandwiched between two flat plates in grinding or polishing. The carrier is provided with a holding hole for holding the glass substrate.

Conventionally, as such a carrier, a resin-impregnated material in which a resin material is impregnated into a glass fabric having glass fibers oriented in two different directions has been widely used from the viewpoint of mechanical strength and cost. In particular, a carrier in which a plurality of layers in which a glass cloth is impregnated with an epoxy resin are laminated is preferably used. However, in this carrier, when the glass substrate is ground or polished, defects such as dented scratches may occur on the end face (outer peripheral sidewall face) of the glass substrate. The depth of the flaw is deeper and longer than other flaws formed on the end face. particles in the polishing slurry adhered to the recessed portion of the flaw, and the glass chip generated by the flaw adhered to the end face, which was a source of dust generation. Specifically, grains in the polishing slurry finally used for polishing were sandwiched between the end face and the carrier, and adhered as fine particles to the concave scratches and secured. The fine particles thus adhered may be detached from the end face of the glass substrate and pass through the main surface of the glass substrate during sputtering performed when the magnetic layer is formed on the glass substrate, thereby causing defects in the magnetic layer. Therefore, the flaw causes a reduction in yield in the production of a glass substrate or a magnetic disk.

In such a situation, a carrier for protecting a glass substrate with fibers such as glass fibers constituting the carrier is known (patent document 1). The carrier has the following structure: a plurality of concave portions are arranged on the inner peripheral wall surface of a holding hole of a glass substrate, and a holding hole buffer area formed only by a resin material and a holding hole reinforcing area formed by a composite material are arranged outside the holding hole buffer area. That is, since the fibers do not leak from the inner peripheral wall surface of the holding hole of the formed glass substrate, the outer peripheral wall surface of the glass substrate inserted into the holding hole can be prevented from being damaged when the polishing step is performed.

Further, a polishing carrier is known which can prevent scratches from being generated on the outer peripheral side surface of the object to be polished due to sliding between the inner peripheral surface of the holding hole of the polishing carrier and the outer peripheral side surface of the object to be polished (patent document 2). In this polishing carrier, a plurality of projections that support an object to be polished by contacting an outer peripheral side surface of the object to be polished are provided on an inner peripheral surface of a holding hole, and the interval between the projections is set to be larger than the width of the projections in the circumferential direction in the inner peripheral surface of the holding hole.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2012 and 218103

Patent document 2: japanese patent laid-open No. 2000-288921

Disclosure of Invention

Problems to be solved by the invention

However, in the carrier of patent document 1, since the inner peripheral wall surface of the holding hole of the glass substrate is a holding hole buffer region formed only of a resin material, the original mechanical strength of the carrier cannot be obtained, and the durability is poor, and therefore, for example, in the case of continuous processing, there is a possibility that the outer peripheral side surface of the glass substrate comes into contact with the angle of the main surface, and a part of the resin material constituting the holding hole buffer region is broken. In this case, the resin material detached from the holding hole buffer region is likely to cause the above-described flaw, and adheres to the main surface of the glass substrate to form a convex portion, thereby forming a defect.

In the polishing carrier described in patent document 2, when a glass substrate is used as a polishing target and polishing is performed, scratches on the outer peripheral side surface (outer peripheral end surface) of the glass substrate cannot be sufficiently suppressed.

Accordingly, an object of the present invention is to provide a polishing carrier, a method for manufacturing the polishing carrier, and a method for manufacturing a magnetic disk substrate, each of which comprises: the occurrence of scratches on the end face of the substrate can be suppressed, and the formation of defects due to adhesion of particles or the like to the main surface of the substrate can be suppressed (adverse effects on the main surface of the substrate can be avoided).

Means for solving the problems

One aspect of the present invention is a carrier for abrasive treatment. The carrier had the following form.

(form 1)

A carrier for polishing treatment, characterized in that,

which is formed of a composite material including fibers oriented in at least one direction and a resin material, and has a holding hole for holding a disc-shaped substrate when the substrate is subjected to a polishing process on a pair of main surfaces thereof with the substrate held between an upper flat plate and a lower flat plate,

the holding hole has a 1 st wall portion configured to bring the substrate into contact with the fibers in a state where the substrate is held in the holding hole and a 2 nd wall portion configured to not bring the substrate into contact with the fibers in a state where the substrate is held in the holding hole, on a circumference of an inner circumferential wall surface of the holding hole,

the 2 nd wall portion is formed in a portion of the inner peripheral wall surface that faces an orientation direction of the fibers including the one direction.

(form 2)

The polishing carrier according to mode 1, wherein the 2 nd wall portion is located further outward in a radial direction of the holding hole than the 1 st wall portion.

In other words, the carrier of embodiment 2 is a polishing carrier having a holding hole for holding a disk-shaped glass substrate when the glass substrate is sandwiched between an upper plate and a lower plate and the main glass surface of the glass substrate is subjected to polishing treatment,

the carrier for polishing treatment is characterized in that,

the carrier for polishing treatment is composed of a plate obtained by impregnating a resin material into a glass fabric in which glass fibers are oriented in 2 directions different from each other,

the contour of the holding hole is determined as follows: the orientation direction wall surface portions facing the 2 orientation directions in which the glass fibers are oriented in the inner peripheral wall surface of the holding hole are located outside an inscribed circle inscribed in the outline of the inner peripheral wall surface of the holding hole.

(form 3)

The polishing carrier according to mode 2, wherein the 1 st wall portion is a 1 st curved surface, a flat surface, or a 2 nd curved surface of a convex shape facing inward in a radial direction of the holding hole, a curvature radius of the 2 nd curved surface is larger than a curvature radius of an inscribed circle that is inscribed in an outline of an inner circumferential wall surface of the holding hole, and an outer circumferential wall surface of the substrate is in contact with the 1 st curved surface, the flat surface, or the 2 nd curved surface, and the 2 nd curved surface is convex outward in the radial direction of the holding hole.

In other words, the carrier of mode 3 is the polishing carrier of mode 2 as set forth in the other expression, wherein wall surfaces on both sides of the orientation direction wall surface portion of the holding hole in the circumferential direction of the holding hole are a 1 st curved surface, a flat surface, or a 2 nd curved surface of a convex shape facing an inner side of the holding hole, a radius of curvature of the 2 nd curved surface is larger than a radius of curvature of the inscribed circle, and is convex with respect to an outer side of the holding hole, and an outer peripheral side wall surface of the glass substrate abuts against the 1 st curved surface, the flat surface, or the 2 nd curved surface.

In the carrier according to aspect 2 or 3 described in the above another expression, the end of the glass fiber of the glass woven fabric may be absent in the 1 st curved surface, the plane, or the 2 nd curved surface of the holding hole, and the end of the glass fiber may be located outside the outline of the holding hole.

(form 4)

The polishing carrier according to mode 3, wherein the 1 st curved surface, the flat surface, or the 2 nd curved surface is provided at 4 or more positions on the circumference of the holding hole.

In other words, the carrier of form 4 is the polishing carrier according to form 2 or 3 described in the above another expression, wherein the 1 st curved surface, the flat surface, or the 2 nd curved surface is provided at 4 or more positions on the circumference of the holding hole.

(form 5)

The polishing treatment carrier according to any one of embodiments 2 to 4, wherein an inscribed circle inscribed in an outline of an inner peripheral wall surface of the holding hole has a diameter larger than a diameter of a disk shape of the substrate.

(form 6)

The polishing carrier according to mode 5, wherein the diameter of the inscribed circle is 1.002 to 1.031 times the diameter of the disk shape of the substrate.

In other words, the carrier according to embodiment 6 is the polishing carrier according to any one of embodiments 2 to 5 described in the above another expression, wherein the diameter of the inscribed circle is 1.002 to 1.031 times the diameter of the disk shape of the glass substrate.

Another aspect of the present invention is a method of manufacturing a substrate for a magnetic disk. The manufacturing method has the following aspects.

(form 7)

A method for manufacturing a magnetic disk substrate, comprising the steps of:

manufacturing a substrate having a circular plate shape;

the method for polishing a glass substrate according to any one of embodiments 2 to 6, wherein the glass substrate is held between an upper plate and a lower plate while the glass substrate is held in a holding hole provided in the carrier for polishing, and the main surface of the glass substrate is polished by relatively moving the glass main surface, the upper plate, and the lower plate.

In other words, the method for manufacturing a magnetic disk glass substrate according to embodiment 7 includes: and a polishing process of polishing a main surface of a glass substrate by holding the glass substrate in a holding hole provided in the polishing carrier according to any one of aspects 2 to 6 expressed by the other expression method, while holding the glass substrate between an upper plate and a lower plate, and relatively moving the glass main surface, the upper plate, and the lower plate.

(form 8)

The method of manufacturing a magnetic disk substrate according to mode 7, wherein, in the polishing process, the outer peripheral side wall surface of the substrate does not abut on the 2 nd wall portion, but abuts on both sides of the 2 nd wall portion.

In other words, the manufacturing method of mode 8 is the manufacturing method of a glass substrate for a magnetic disk according to mode 7 described in the above another expression, wherein the outer peripheral side wall surface of the glass substrate does not abut on the alignment direction wall surface portion but abuts on both sides of the alignment direction wall surface portion in the polishing process.

(form 9)

The method of manufacturing a magnetic disk substrate according to aspect 7 or 8, wherein the polishing treatment carrier is produced by: a holding hole is formed in a plate material composed of a composite material including fibers oriented in at least one direction and a resin material, and the plate material is etched after the holding hole is formed.

Another aspect of the invention is a carrier for abrasive treatment. The carrier has the following form.

(form 10)

The polishing treatment carrier according to mode 1, wherein a fiber-nonexistent region is disposed in an annular region extending from the inner peripheral wall surface of the holding hole to the outside in the radial direction of the holding hole, the fiber-nonexistent region being provided on the outside in the radial direction of the holding hole with respect to the 2 nd wall portion and having no fiber in the orientation direction.

In other words, the carrier of embodiment 10 is a carrier having a holding hole for holding a plate-shaped glass substrate when the glass substrate is sandwiched between an upper plate and a lower plate and the main surface of the glass substrate is polished,

the carrier is characterized in that it is,

the carrier is reinforced by a glass fabric in which a plurality of glass fibers are arranged in any of 2 orientation directions, and is composed of a resin-impregnated substrate in which the glass fabric is impregnated with a resin material,

a ring-shaped region extending outward from an inner wall surface of the holding hole, wherein 1 st reinforcing regions reinforced by only 1 st glass fibers oriented in one direction of the orientation directions and 2 nd reinforcing regions reinforced by only 2 nd glass fibers oriented in the other direction of the orientation directions are alternately arranged so as to be spaced apart from each other in a circumferential direction,

the 1 st reinforcing region is provided outside a 1 st inner wall portion of the inner wall surface of the holding hole facing the 2 nd glass fiber orientation direction, and the 2 nd reinforcing region is provided outside a 2 nd inner wall portion of the inner wall surface facing the 1 st glass fiber orientation direction.

(form 11)

The polishing treatment carrier according to mode 10, wherein the fiber nonexistence region is formed by a tip end of the fiber facing the 2 nd wall portion not reaching an inner peripheral wall surface of the holding hole.

In other words, the carrier of form 11 is the carrier according to form 10 described in the above another expression, wherein the 1 st reinforcing region is formed such that the ends of the 2 nd glass fibers do not reach the inner wall surface of the holding hole, and the 2 nd reinforcing region is formed such that the ends of the 1 st glass fibers do not reach the inner wall surface of the holding hole.

Another aspect of the present invention is a method for manufacturing a polishing carrier. The manufacturing method has the following aspects.

(form 12)

A method for manufacturing a carrier for polishing treatment, the carrier for polishing treatment having a holding hole for holding a disk-shaped substrate when the substrate is polished by sandwiching the substrate between an upper plate and a lower plate,

the method for producing a polishing carrier is characterized by comprising:

a step 1 of forming the holding hole on a plate material composed of a composite material including fibers oriented in at least one direction and a resin material; and

a 2 nd step of etching at least the plate material in which the holding holes are formed to produce the carrier,

in the 2 nd step, the fibers are etched at a portion of the inner peripheral wall surface facing the orientation direction of the fibers including the one direction.

In other words, the manufacturing method of embodiment 12 is a manufacturing method of a carrier having a holding hole for holding a disk-shaped glass substrate by sandwiching the glass substrate between an upper plate and a lower plate and polishing a main surface of the glass substrate,

the method for producing the carrier is characterized by comprising:

a step 1 of forming the holding hole in a resin-impregnated substrate in which a resin material is impregnated into the glass cloth, the glass cloth being reinforced by a plurality of glass fibers arranged in any of 2 orientation directions; and

a 2 nd step of manufacturing the carrier by etching the resin-impregnated substrate in which the holding holes are formed,

in the step 2, the glass fibers exposed to the orientation direction are etched in an inner wall portion of the inner wall surface of the holding hole facing in any direction of the orientation direction of the glass fibers, so that a reinforcing region is formed in a ring-shaped region extending outward from the inner wall surface of the holding hole of the carrier, the reinforcing region being reinforced only by the glass fibers having an orientation direction different from the orientation direction of the etched glass fibers.

(form 13)

The method of manufacturing a polishing-treatment carrier according to mode 12, wherein in the 2 nd step, a mask material is provided on a portion of the plate material constituting a portion other than the portion of the inner peripheral wall surface facing the orientation direction before the etching, and the mask material is removed after the etching.

In other words, the method of manufacturing the carrier according to mode 13 is the method of manufacturing the carrier according to mode 12 described in the above-mentioned another expression, wherein in the step 2, a mask material is provided in a portion other than the reinforcement region in the annular region before the etching, and the mask material is removed after the etching.

(form 14)

The method for manufacturing a polishing carrier according to mode 12 or 13, wherein in the 2 nd step, an etching agent for etching the fibers is applied to a portion of the plate material constituting a portion of the inner peripheral wall surface facing the orientation direction, thereby performing the etching.

In other words, the method of manufacturing the carrier according to aspect 14 is the method of manufacturing the carrier according to aspect 12 or 13 described in the above-mentioned another expression, wherein in the step 2, an etchant for etching the glass fiber is applied to a portion constituting the reinforcement region in the annular region of the resin-impregnated substrate, and the etching is performed.

(form 15)

The method of manufacturing a polishing-treatment carrier according to any one of aspects 12 to 14, wherein in the 2 nd step, before the etching, the plate material and 1 or more other substrates having holding holes formed at positions corresponding to positions where the holding holes are formed in the plate material are arranged so as to overlap in a plate material thickness direction.

In other words, the method of manufacturing the carrier according to aspect 15 is the method of manufacturing the carrier according to any one of aspects 12 to 14 described in the above another expression, wherein, in the step 2, the resin-impregnated substrate and 1 or more other substrates having holding holes formed at positions corresponding to positions of the resin-impregnated substrate where the holding holes are formed are arranged to overlap in a plate thickness direction before the etching.

(form 16)

The method for manufacturing a polishing-treatment carrier according to mode 15, wherein the other substrate is made of a composite material including fibers oriented in at least one direction and a resin material,

when the plate material is referred to as a 1 st plate material and the other substrate is referred to as a 2 nd plate material, the direction in which the fibers are oriented is aligned between the plate materials when the 1 st plate material and the 2 nd plate material are arranged to overlap in the 2 nd step.

In other words, the method of manufacturing the carrier according to mode 16 is the method of manufacturing the carrier according to mode 15 described in the above-mentioned another expression, wherein the other substrate is reinforced by a glass cloth in which a plurality of glass fibers are arranged in any of 2 orientation directions, and the glass cloth is impregnated with a resin material,

when the resin-impregnated substrate is referred to as a 1 st resin-impregnated substrate and the other substrate is referred to as a 2 nd resin-impregnated substrate, the alignment direction is aligned between the resin-impregnated substrates when the 1 st resin-impregnated substrate and the 2 nd resin-impregnated substrate are arranged to be overlapped in the 2 nd step.

(form 17)

when the plate material is referred to as a 1 st plate material and the other substrate is referred to as a 2 nd plate material, in the 1 st step, the holding holes are formed so that the direction in which the fibers are oriented is aligned between the plate materials when the 1 st plate material and the 2 nd plate material are arranged to overlap each other.

In other words, the method of manufacturing the carrier according to mode 17 is the method of manufacturing the carrier according to mode 15 described in the above-mentioned another expression, wherein the other substrate is reinforced by a glass cloth in which a plurality of glass fibers are arranged in any of 2 orientation directions, and the glass cloth is impregnated with a resin material,

when the resin-impregnated substrate is referred to as a 1 st resin-impregnated substrate and the other substrate is referred to as a 2 nd resin-impregnated substrate, the holding holes are formed so that the orientation directions are aligned between the resin-impregnated substrates when the 1 st resin-impregnated substrate and the 2 nd resin-impregnated substrate are arranged to overlap each other in the 1 st step.

(form 18)

A method for manufacturing a magnetic disk substrate, comprising:

a polishing treatment of polishing a main surface of a substrate while the polishing treatment carrier according to any one of

embodiments

10 and 11 or the polishing treatment carrier manufactured by the method for manufacturing a polishing treatment carrier according to any one of embodiments 12 to 17 holds the substrate.

In other words, the method of manufacturing the embodiment 18 is a method of manufacturing a glass substrate for a magnetic disk, including:

a polishing process of polishing a main surface of a glass substrate in a state where the carrier according to

form

10 or 11 described in the above another expression method or the carrier manufactured by the method for manufacturing a carrier according to any one of forms 12 to 17 described in the above another expression method holds the glass substrate.

Effects of the invention

According to the method for manufacturing a magnetic disk substrate and the carrier for polishing treatment of the present invention, it is possible to suppress the occurrence of scratches on the end face of the substrate and further suppress the occurrence of defects on the main surface of the substrate.

Further, according to the polishing treatment carrier of the present invention, the fibers oriented in the orientation direction (oriented direction) of the fibers do not exist in the vicinity of the inner wall portion facing the orientation direction, and for example, the carrier is reinforced only by the fibers oriented in the orientation direction different from the fibers. Thus, when the substrate is polished, the occurrence of scratches on the end face of the substrate can be prevented, and the strength of the carrier in the vicinity of the inner wall surface of the holding hole can be ensured, thereby suppressing the occurrence of contamination (foreign matter) caused by the resin material. According to the method for producing a polishing carrier of the present invention, such a carrier can be obtained. According to the method for manufacturing a substrate for a magnetic disk of the present invention, it is possible to prevent scratches from being generated on the end surface of the substrate during polishing treatment, and to suppress the occurrence of contamination caused by the resin material, thereby suppressing the occurrence of contamination or scratches on the main surface of the substrate.

Drawings

Fig. 1 is an exploded perspective view of an example of a grinding apparatus (double-side polishing apparatus) using a carrier according to embodiment 1.

Fig. 2 is a cross-sectional view of an example of the grinding apparatus shown in fig. 1.

Fig. 3 is a diagram for explaining an example of the relationship between the inner peripheral wall surface of the holding hole and two orientation directions in which the glass fibers are oriented in embodiment 1.

Fig. 4 is a diagram showing an example of the outline shape of the holding hole of the carrier according to embodiment 1.

Fig. 5 is a perspective view showing the carrier shown in fig. 1 focusing on one holding hole.

Fig. 6 is a diagram for explaining a state in which the inner peripheral wall surface of the holding hole of the carrier of embodiment 1 abuts against the glass substrate.

Fig. 7 (a) and (b) are views showing another example of the outline shape of the holding hole of the carrier according to embodiment 1.

Fig. 8 (a) to (c) are views showing still another example of the outline shape of the holding hole of the carrier according to embodiment 1.

Fig. 9 is a diagram showing still another example of the outline shape of the holding hole of the carrier according to embodiment 1.

Fig. 10 is a plan view of the carrier of embodiment 2.

Fig. 11 is a perspective view showing the carrier shown in fig. 10 focusing on one holding hole.

Fig. 12 is a view showing the carrier of fig. 1 focusing on the annular region.

Fig. 13 is a view showing the carrier of fig. 1 focusing on the annular region.

Detailed Description

Embodiment 1

Next, a polishing carrier and a method for manufacturing a magnetic disk substrate according to embodiment 1 will be described in detail. In the present embodiment, the polishing treatment includes: grinding of a glass substrate and polishing of a glass substrate to reduce the roughness of the glass main surface of the glass substrate after grinding. Therefore, the polishing carrier is a carrier that can be used for grinding and polishing a glass substrate. The carrier of the embodiment described below is described for use in polishing, but may be used for grinding.

The present inventors have made a practical study on a carrier and a substrate such as a glass substrate in order to solve the conventional problems. The carrier is composed of a plate (plate) of a glass fabric impregnated with a resin material in which glass fibers are oriented in two different directions, for example, two orthogonal directions. In this carrier, glass fabrics are laminated in a plurality of layers, and the orientation direction of the glass fibers in each glass fabric is the same. Further, the inventors have made the following guesses: in the inner peripheral wall surface of the holding hole of the glass substrate, at orientation direction wall surface portions (the 2 nd wall portion described later) respectively facing two orientation directions in which the glass fibers are oriented, when the ends of the glass fibers are brought into contact with the outer peripheral side wall surface of the glass substrate, the resin material is slightly bent, whereby the ends of the glass fibers slightly protrude (fly out), and the ends of the glass fibers are poked against the outer peripheral side wall surface of the glass substrate or the glass fibers protruding from the surface of the resin material are poked against the outer peripheral side wall surface of the glass substrate, thereby causing whether or not the outer peripheral side wall surface of the glass substrate is scratched.

In addition, the present inventors found that: in the polishing carrier of the above-described known (patent document 2), although the protrusions are provided, the orientation direction of the glass fibers is not considered. The inventors have also found that: the glass fibers at the ends of the protrusions protruding parallel to the orientation direction of the glass fibers cause scratches on the outer peripheral end surface of the glass substrate. Since the force is particularly easily concentrated at the end of the protrusion protruding in parallel with the orientation direction of the glass fiber, the outer peripheral end face of the glass substrate is easily scratched. Further, as a result of repeating the test, the following aspects of the carrier for polishing and the method for producing a substrate were invented.

In the present specification, the substrate includes an aluminum substrate, a silicon wafer, and the like in addition to a glass substrate, but in the following description, a glass substrate is described as a representative example. The aluminum substrate includes a substrate made of aluminum alloy containing other metal elements such as magnesium, in addition to a substrate made of pure aluminum. A plated film of, for example, NiP (nickel nitride) may be provided on the surface of the aluminum substrate or the like.

In the present specification, the fibers include metal fibers as well as glass fibers, but in the following description, glass fibers are typically used as an example. In addition, in the case of simply called a fiber, a plurality of fibers are shown except for the case described in advance. Further, the number of the orientation directions of the fibers may be 1,2, 3, or the like, and in the following description, a case of 2 directions will be described as an example as a representative example.

In the present specification, the inner side of the holding hole means a direction from the center of the holding hole to the outer side in the radial direction of the holding hole or a direction in which the holding hole is narrowed, and the outer side of the holding hole means a direction from the center of the holding hole to the inner side in the radial direction of the holding hole or a direction in which the holding hole is enlarged.

(grinding device)

A polishing apparatus for a glass substrate using the polishing carrier according to the present embodiment will be described with reference to fig. 1 and 2. The polishing carrier has a holding hole for holding a disk-shaped glass substrate when the glass substrate is sandwiched between an upper plate and a lower plate and the main glass surface of the glass substrate is polished. Fig. 1 is an exploded perspective view of a polishing apparatus (double-sided polishing apparatus). Fig. 2 is a sectional view of the polishing apparatus. Since the grinding apparatus also has the same configuration as the polishing apparatus, the description of the grinding apparatus will be omitted.

As shown in fig. 1, the polishing apparatus includes a pair of upper and lower flat plates, i.e., an upper flat plate 40 and a lower flat plate 60. The glass substrate G having an annular shape is held between the upper plate 40 and the lower plate 60, and the glass substrate G and each of the upper plate 40 and the lower plate 60 are moved relative to each other by moving either one or both of them, whereby both main surfaces of the glass substrate G can be polished. Further, a polishing slurry containing particles was supplied between the glass substrate and the flat plate. Hereinafter, the upper plate 40 and the lower plate 60 will be collectively referred to as a "plate".

Referring to fig. 1 and 2, the structure of the polishing apparatus will be described in more detail.

In the polishing apparatus, a polishing pad 10 is attached to the upper surface of the lower plate 60 and the lower surface of the upper plate 40. In fig. 1, the polishing pad 10 is in the form of a sheet. As the polishing pad 10, for example, a foamed urethane resin or the like can be used.

The carrier 30 has a holding hole for holding the disk-shaped glass substrate G when the main surface of the glass substrate G is polished by sandwiching the glass substrate G between the upper plate 40 and the lower plate 60. Specifically, the carrier 30 has a tooth portion 31 provided on the outer peripheral portion and meshing with the sun gear 61 and the

internal gear

62, and 1 or more holding holes 32 for receiving and holding the glass substrates G. The sun gear 61, the internal gear 62 provided on the outer periphery, and the disk-shaped carrier 30 constitute a planetary gear mechanism centered on the central axis CTR as a whole. The disk-shaped carrier 30 is meshed with the sun gear 61 on the inner circumferential side and meshed with the internal gear 62 on the outer circumferential side, and accommodates and holds 1 or more glass substrates G. On the lower plate 60, the carrier 30 revolves while rotating on its axis as a planetary gear, and the glass substrate G is moved relative to the lower plate 60. For example, if the sun gear 61 rotates counterclockwise, the carrier 30 rotates clockwise, and the internal gear 62 rotates counterclockwise. As a result, relative movement is generated between the lower plate 60 and the glass substrate G. Similarly, the glass substrate G and the upper plate 40 may be relatively moved.

In the above-described operation of the relative movement, the upper plate 40 presses the glass substrate G held by the carrier 30 (i.e., in the vertical direction) with a predetermined pressure, thereby pressing the polishing pad 10 against the glass substrate G. Then, as shown in fig. 2, the polishing slurry is supplied from a supply tank 71 to a space between the glass substrate G and the polishing pad 10 through 1 or more pipes 72 by a pump (not shown).

(Carrier)

The carrier 30 has a laminated structure in which a plurality of glass fabrics (JIS R3414: 2012) are laminated. The reason why the carrier 30 is constructed as a laminated structure using a glass cloth is as follows: during polishing, the carrier 30 is subjected to bending deformation and shearing deformation by the forces received from the sun gear 61 and the internal gear 62, and as a result, it is necessary to ensure bending rigidity, shearing rigidity, and mechanical strength in order to prevent the glass substrate G from being damaged. The glass fabric is produced by weaving glass filaments (JISR 3413: 2012, hereinafter, referred to as glass yarn) composed of glass fibers. The carrier 30 is formed by laminating and pressure-bonding the layers of the glass cloth impregnated with the resin material. That is, the carrier 30 is made of a plate material (hereinafter, referred to as a resin-impregnated substrate) in which glass fabric formed by orienting glass fibers in 2 directions different from each other is arranged in a resin material. As the resin material, a thermoplastic resin such as an epoxy resin or a phenol resin can be used.

Fig. 3 is a diagram for explaining an example of the relationship between the inner peripheral wall surface 36 of the holding hole 32 of the carrier 30 and 2 orientation directions in which the glass fibers are oriented in the present embodiment. For convenience of illustration, the contour shape of the inner peripheral wall surface 36 shown in fig. 3 is shown as a circle, but as will be described later, it has irregularities along the circumference of the holding hole 32. The carrier 30 is a plate formed by impregnating a resin material into a glass cloth having glass fibers oriented in 2 directions (X direction and Y direction) different from each other. The orientation directions of the glass fibers in each layer of the glass fabric are both the X direction and the Y direction. The glass fabric is a woven fabric in which glass fibers (33,34) having a filament diameter of several μm are arranged at a density of, for example, 200 to 800 fibers per unit.

Fig. 4 is a diagram showing an example of the outline shape of the holding hole 32 of the carrier 30. Fig. 5 is a perspective view showing the carrier 30 shown in fig. 1 focusing on one holding hole 32. Fig. 6 is a diagram for explaining a state in which the inner peripheral wall surface 36 of the holding hole 32 of the carrier 30 abuts against the glass substrate G.

The carrier 30 of the present embodiment is formed of a composite material including glass fibers and a resin material oriented in at least one direction, and has holding holes 32 for holding a disk-shaped substrate when the substrate is polished by sandwiching the substrate between an upper plate and a lower plate. The holding hole 32 has a 1 st wall portion (a portion excluding the 2 nd wall portion from the 1 st curved surface 37, the flat surface 38, and the 2 nd curved surface 39 described later) configured to contact the substrate with the fibers in a state where the substrate is held in the holding hole 32, and a 2 nd wall portion (an alignment direction wall portion 35 described later) configured to not contact the substrate with the fibers, on the periphery of the inner peripheral wall surface of the holding hole. The 2 nd wall portion is formed in a portion of the inner peripheral wall surface of the holding hole 32 that faces the orientation direction of the fibers including one direction. Further, the carrier 30 of embodiment 1 is characterized in that the 2 nd wall portion is located further outward in the radial direction of the holding hole than the 1 st wall portion. In addition, the orientation direction of the fibers including one direction means all directions in which the fibers in the carrier are oriented. Therefore, the 2 nd wall portions are formed on the inner peripheral wall surface of the holding hole so as to correspond to all the orientation directions of the fibers, and specifically, the 2 nd wall portions are formed on the inner peripheral wall surface so as to be 2 times as many as the number of the orientation directions of the fibers. For example, in the case where the number of the orientation directions of the fibers is 2, the 2 nd wall portion is formed at 4 of the inner peripheral wall surface. This point is also the same in embodiment 2 described later.

The profile of the holding hole 32 is set as follows: in the side wall surface of the holding hole 32 shown in fig. 4, all the orientation direction wall surface portions 35 facing 2 orientation directions (X direction, Y direction) in which the glass fibers are oriented are located outside an inscribed circle inscribed in the outline of the inner peripheral wall surface of the holding hole 32. Thus, the outer peripheral side wall surface of the glass substrate G during the polishing process does not abut on the alignment direction wall surface portion 35, but abuts on both sides of the alignment direction wall surface portion 35.

Here, as shown in fig. 3, the orientation direction wall surface portion 35 is a portion (a portion indicated by a thick solid line in fig. 3) of the inner peripheral wall surface of the holding hole 32 in the azimuth direction viewed from the center point of the inscribed circle, in which, when the inscribed circle C inscribed in the outline of the inner peripheral wall surface of the holding hole 32 is assumed, a portion on the inscribed circle having the normal direction of the inscribed circle (the direction orthogonal to the line connecting the inscribed circles) and the orientation direction of the glass fibers (33,34) aligned is positioned. In this case, the term "the normal direction coincides with the orientation direction" means that, as shown in fig. 3, a wall surface portion in a range where θ is 40 ° (± 20 ° with respect to the center line of the drawing) is set as the allowable range of the orientation direction wall surface portion 35, with a portion where the directions completely coincide as the center. In such an allowable range, for example, θ is 22.5 ° (± 11.25 ° with respect to the center line of the drawing). The holding hole 32 is formed in a substantially circular shape, and therefore has 4 orientation direction wall surface portions 35 centering on positions where θ is 0 °, θ is 90 °, θ is 180 °, and θ is 270 °, respectively, when the azimuth angle in the X direction is 0 °. In the inner peripheral wall surface 36 of the holding hole 32 shown in fig. 4, the orientation direction wall surface portion 35 is located outside an inscribed circle (indicated by a dotted line in fig. 4) inscribed in the outline of the inner peripheral wall surface of the holding hole 32. Specifically, in the example shown in fig. 4, the 1 st curved surface 37 of the orientation direction wall surface portion 35 is formed in a convex shape toward the inside of the holding hole 32, in the wall surfaces on both sides in the circumferential direction of the holding hole 32. The 1 st curved surface 37 of the convex shape meets the inscribed circle. Therefore, as shown in fig. 6, the outer peripheral side wall surface of the glass substrate G does not abut on the alignment direction wall surface portion 35, but abuts on both sides of the alignment direction wall surface portion 35. Thus, the orientation direction wall surface portion 35 facing the orientation direction of the glass fibers (33,34) is positioned outside the inscribed circle inscribed in the outline of the inner peripheral wall surface of the holding hole 32, and does not abut on the outer peripheral side wall surface of the glass substrate G. Therefore, even if the glass fibers (33,34) are exposed from the resin material in the orientation direction wall surface portion 35, the ends of the glass fibers (33,34) do not contact the outer peripheral side wall surface of the glass substrate G, and therefore, the outer peripheral side wall surface of the glass substrate G can be prevented from being scratched. This can prevent defects from being formed due to adhesion of particles to the main surface of the glass substrate G. In addition, in the end surfaces on the inner and outer peripheral sides of the glass substrate G, a side wall surface perpendicular to the main surface and a chamfered surface (via surface) connecting the side wall surface and the main surface are formed by chamfering, and in this case, it is possible to prevent the occurrence of a flaw on the side wall surface, particularly, on the end surface on the outer peripheral side (outer peripheral side wall surface) of the glass substrate G.

Further, the 21 st curved surfaces 37 of the convex shape located on both sides in the circumferential direction of the inner circumferential wall surface of the holding hole 32 with respect to the orientation direction wall surface portion 35 and facing the inside of the holding hole 32 abut on the glass substrate G, and the force applied to the outer circumferential wall surface of the glass substrate G is dispersed, so that the 21 st curved surfaces 37 of the convex shape abut on the outer circumferential wall surface of the glass substrate G and the generation of scratches can be suppressed. In addition, when the shape of the holding hole 32 is a simple circular shape as in the conventional art, since the contact is made at 1, the force is concentrated and the scratch is likely to occur.

In addition, when a plurality of holding holes 32 are provided in 1 carrier 30, it is preferable that the 1 st curved surface 37 of a convex shape facing the inside of the holding hole 32 be provided in all the holding holes 32 in consideration of the orientation direction of the glass fiber. The 1 st curved surface 37 of the convex shape is formed in all the holding holes 32 formed in the 1 carrier 30 in consideration of the orientation of the glass fiber included in the carrier 30. In a conventional polishing carrier having a convex protrusion (notch), as shown in patent document 2, for example, the orientation of the notch is not noticed, and therefore, when a plurality of holding holes are formed in 1 carrier, glass fibers may protrude in the vertical direction in a substrate support portion at the end of the notch. Therefore, when polishing or processing is performed using a carrier having a plurality of holding holes, it is not possible to prevent contact with glass fibers protruding in the vertical direction for all substrates in a batch.

The maximum projection amount of the 1 st curved surface 37 of the convex shape in the radial direction from the virtual circle constituting a part of the wall surface portion 35 in the orientation direction to the virtual circle in the center direction of the virtual circle is preferably 0.3 to 5mm, and more preferably 1 to 3 mm. The 1 st curved surface 37 of the convex shape may have a curved surface as long as it has a curved surface, and as shown in the drawing, may have a curved surface that bulges outward from a portion inside the 1 st curved surface 37 of the convex shape and is curved, or may have a curved surface or a flat surface that bulges inward from the outside of the 1 st curved surface of the convex shape as shown in fig. 1 of patent document 2. When the convex 1 st curved surface 37 has a curved surface which is curved so as to bulge outward from an inner portion of the convex 1 st curved surface 37, the curvature radius R of the curved surface is preferably 5 to 150mm, and more preferably 10 to 50 mm. The number of the 1 st curved surfaces of the convex shape is preferably 4 or more, and more preferably 8 or more.

In the example shown in fig. 4, 8 convex 1 st curved surfaces 37 are provided toward the inside of the holding hole 32, but the number of the 1 st curved surfaces 37 arranged on the circumference is not limited to 8. Fig. 7 (a) and (b) are diagrams showing another example of the outline shape of the holding hole 32 of the carrier 30. As shown in (a), (b) of fig. 7, the number of configurations may be 6, 10, or the like. In this way, the number of arrangement is not limited as long as the 1 st curved surface 37 having a convex shape is provided on the wall surface on both sides of the orientation direction wall surface portion 35 facing the 2 orientation directions (X direction, Y direction) in which the glass fibers (33,34) are oriented.

Further, flat surfaces 38 may be provided on the wall surfaces on both sides of the orientation direction wall surface portion 35 instead of the convex 1 st curved surface 37. Fig. 8 (a) to (c) show still another example of the outline shape of the holding hole 32 of the carrier 30. As long as the outer peripheral side wall surface of the glass substrate G does not abut on the orientation direction wall surface portion 35 but abuts on both sides of the orientation direction wall surface portion 35, as shown in fig. 8 (a) to (c), in the outline shape of the holding hole 32, a flat surface 38 can be formed in the wall surface on both sides of the orientation direction wall surface portion 35 in the 2 orientation directions (X direction, Y direction) in which the glass fibers (33,34) are oriented. The flat surface 38 meets the inscribed circle C. That is, the outline shape of the holding hole 32 may be a regular polygon or a polygon such as a regular hexagon, a regular octagon, or a regular decagon. In the case of the regular hexagon shown in fig. 8 (a), since the 4 positions of the orientation direction wall surface portion 35 cannot be made to correspond to the positions of the vertices of the regular hexagon, as shown in fig. 8 (a), the orientation of the regular hexagon with respect to the 2 orientation directions (X direction, Y direction) in which the glass fibers (33,34) are oriented is adjusted so that the position of the orientation direction wall surface portion 35 is located at a position deviated from the positions of the vertices of the regular hexagon. Similarly, in the case of the regular decagon shown in fig. 8 (c), since the positions of the vertices of the regular decagon cannot be corresponded to the positions of the 4 positions of the orientation direction wall portion 35, the orientation of the regular decagon with respect to the 2 orientation directions (X direction, Y direction) in which the glass fibers (33,34) are oriented is adjusted so that the position of the orientation direction wall portion 35 is located at a position deviated from the position of the vertices of the regular decagon.

In the example of the regular octagon shown in fig. 8 (b), since the positions of the 4 orientation direction wall portions 35 can be made to correspond to the positions of the vertices of the regular octagon, the orientation of the regular octagon with respect to the 2 orientation directions (X direction, Y direction) in which the glass fibers (33,34) are oriented can be adjusted so that the positions of the orientation direction wall portions 35 are positioned at the positions of the vertices of the regular octagon.

In the examples shown in fig. 8 (a) to (C), the flat surface 38 is in contact with the inscribed circle C in the inner peripheral wall surface of the holding hole 32. By setting the contour of the holding hole 32 so that the alignment direction wall surface portions 35 are all positioned outside the inscribed circle C inscribed in the contour of the inner circumferential wall surface of the holding hole 32, the outer circumferential side wall surface of the glass substrate G in the polishing process abuts on both sides of the alignment direction wall surface portion 35 without abutting on the alignment direction wall surface portion 35. That is, the wall surfaces of the orientation direction wall surface portion 35 of the holding hole 32 on both sides in the circumferential direction of the holding hole 32 are flat surfaces 38, and the outer peripheral wall surface of the glass substrate G during the polishing process abuts on the portions of the flat surfaces 38. Therefore, even if the glass fibers (33,34) are exposed from the resin material in the orientation direction wall surface portion 35, the ends of the glass fibers (33,34) do not come into surface contact with the outer peripheral side wall surface of the glass substrate G, and therefore, the outer peripheral side wall surface of the glass substrate G can be prevented from being scratched. This can prevent the formation of defects due to the adhesion of particles or the like to the main surface of the glass substrate G.

Also, the wall surfaces of the orientation direction wall surface portion 35 of the holding hole 32 on both sides in the circumferential direction of the holding hole 32 may not be the flat surfaces 38. Fig. 9 shows still another example of the outline shape of the holding hole of the carrier 30. Instead of the flat surface 38, a 2 nd curved surface 39 having a radius of curvature larger than that of an inscribed circle C inscribed in the outline of the inner peripheral wall surface of the holding hole 32 may be used. The 2 nd curved surface 39 has a convex shape on the outer side of the holding hole 32 (a concave shape on the inner side of the holding hole 32). The 2 nd curved surface 39 meets the inscribed circle C. In this case, as shown in the drawing, the contour of the holding hole 32 is set so that the orientation direction wall surface portions 35 are all located outside the inscribed circle C inscribed in the contour of the inner peripheral wall surface of the holding hole 32 in the inner peripheral wall surface of the holding hole 32. Therefore, the outer peripheral side wall surface of the glass substrate G during the polishing process does not abut on the alignment direction wall surface portion 35, but abuts on the 2 nd curved surface 39 on both sides of the alignment direction wall surface portion 35. Therefore, even if the glass fibers (33,34) are exposed from the resin material in the orientation direction wall surface portion 35, the ends of the glass fibers (33,34) do not come into contact with the outer peripheral side wall surface of the glass substrate G, and therefore, the outer peripheral side wall surface of the glass substrate G can be prevented from being scratched. This prevents the formation of defects due to adhesion of particles to the main surface of the glass substrate G.

The ends of the glass fibers (33,34) are preferably located on the inner peripheral wall surface 36 of the holding hole 32 from the viewpoint of improving the mechanical strength of the carrier 30. That is, it is preferable that the ends of the glass fibers (33,34) are located on the surface of the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39.

However, from the viewpoint of further preventing the generation of scratches on the outer peripheral side wall surface of the glass substrate G, it is preferable that the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39 located on both sides of the orientation direction wall surface portion 35 do not form the ends of the glass fibers (33,34) of the glass cloth, and the ends of the glass fibers (33,34) are located outside the outline of the holding hole 32 with respect to the outline. Since the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39 positioned on both sides of the orientation direction wall surface portion 35 is not the orientation direction wall surface portion 35, even if the ends of the glass fibers (33,34) are positioned on the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39, it is difficult to generate scratches on the outer peripheral side wall surface of the glass substrate G. However, even if the glass fibers (33,34) are not exposed from the resin material in the orientation direction wall surface portion 35, the resin material surrounding the glass fibers (33,34) is slightly compressed when contacting the glass substrate G during polishing, and thus the glass fibers (33,34) may protrude from the resin material. In addition, during the polishing process, the resin material may rub against the glass substrate G to abrade the resin material, thereby exposing the glass fibers (33, 34). In this case, in order to suppress the occurrence of scratches on the outer peripheral side wall surface of the glass substrate G, it is preferable that the ends of the glass fibers (33,34) be positioned outside the outline of the holding hole 32 with respect to the outline of the holding hole 32. In this case, the distance between the ends of the glass fibers (33,34) and the outline of the holding hole 32 is preferably less than 2 μm from the viewpoint of ensuring the mechanical strength of the carrier 30. In this way, the glass fibers (33,34) whose ends do not reach the inner peripheral wall surface 36 of the holding hole 32 are obtained by etching the glass fibers (33,34) exposed to the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39 of the carrier 30 using an etching solution containing hydrofluoric acid. That is, it is preferable that the glass fiber reinforced resin sheet is obtained by reinforcing a glass cloth in which a plurality of glass fibers are arranged in any of 2 orientation directions, forming a holding hole 32 in a resin-impregnated substrate in which the glass cloth is impregnated with a resin material, and etching the resin-impregnated substrate after forming the holding hole 32.

Further, on the inner peripheral wall surface of the holding hole 32 of the carrier 30, the glass fibers (33,34) are subjected to etching treatment using an etching solution containing hydrofluoric acid in the 1 st curved surface 37, the flat surface 38 or the 2 nd curved surface 39, and then to removal treatment for removing fluoroaluminate generated by the etching treatment using an acidic electrolyte solution containing metal ions. First, by performing this etching treatment, the probability of occurrence of a flaw on the outer peripheral end face of the glass substrate G can be further reduced. Further, since the removal process is performed after the etching process to remove the fine particles of the fluoroaluminate remaining on the carrier 30, it is possible to prevent the fine particles of the fluoroaluminate from entering between the glass substrate G and the upper plate 40 or the lower plate 60 during polishing to cause scratches on the main surface of the glass substrate G or to prevent the fine particles from passing through the main surface of the glass substrate G during sputtering to form a magnetic layer on the glass substrate G to cause defects in the magnetic layer.

The 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39 on both sides of the orientation direction wall surface portion 35 is preferably provided at 4 or more positions on the circumference of the holding hole 32 in terms of dispersing the force when the inner circumferential wall surface 36 of the holding hole 32 abuts against the outer circumferential side wall surface of the glass substrate G. When the contact force is concentrated without being dispersed, the carrier 30 is locally deformed by a locally large force, and thereby the carrier 30 is damaged or the glass substrate G enters a gap where the carrier 30 is deformed and bent, and there is a possibility that the glass substrate G or the polishing pad is damaged during polishing.

Further, in a point that the outer peripheral side wall surface of the glass substrate G is not brought into contact with the orientation direction wall surface portion 35 but is surely brought into contact with the wall surfaces on both sides of the orientation direction wall surface portion 35, the diameter of the inscribed circle C inscribed in the outline of the inner peripheral wall surface of the holding hole 32 is preferably substantially the same as or slightly larger than the disk shape of the glass substrate G to be polished, and is 1.002 to 1.031 times the diameter of the disk shape constituting the glass substrate G. If the amount is smaller than this range, it may be difficult to hold the glass substrate in the holding hole or take out the glass substrate from the holding hole. If the thickness is larger than this range, the glass substrate is likely to be strongly abutted against the inner peripheral wall surface of the holding hole during processing, and the end surface is likely to be scratched.

In the polishing apparatus shown in fig. 1 and 2, the polishing pad is attached to the upper plate 40 or the lower plate 60, but particles may be fixed to the upper plate 40 or the lower plate 60, and the refrigerant may be supplied between the glass substrate G and the upper plate 40 or the lower plate 60. The carrier 30 may be used in a grinding apparatus for grinding the glass substrate G in addition to the polishing apparatus.

The carrier 30 can be used in a polishing apparatus, and further, in a grinding apparatus having a configuration substantially similar to that of the polishing apparatus, and can be applied to the production of a magnetic disk glass substrate as described below. In grinding using a grinding apparatus for a glass substrate, the roughness Ra of the main surface of the glass substrate after grinding is larger than that of polishing. In such grinding, the main surface of the glass substrate may be ground by supplying a grinding fluid between each of the upper and lower flat plates and the glass substrate. Alternatively, fixed particles may be provided on each of the upper plate and the lower plate, and the main surface of the glass substrate may be ground by supplying a lubricating liquid between the fixed particles and the glass substrate.

(method of manufacturing magnetic disk substrate)

According to the manufacturing method of the present embodiment, first, a molding process of a glass blank to be a material of a plate-shaped magnetic disk glass substrate having a pair of main surfaces is performed. Subsequently, the rough grinding process of the glass blank is performed. Thereafter, the glass blank is subjected to shape processing and end face polishing. Thereafter, the glass substrate obtained from the glass blank was subjected to finish grinding using fixed pellets. Thereafter, the glass substrate is subjected to the 1 st polishing process, the chemical strengthening process, and the 2 nd polishing process. In the present embodiment, the above-described processes are performed by the above-described flow, but the above-described processes need not be all performed, and these processes may be appropriately omitted. The order of processing can be changed as appropriate. Next, each process will be described.

(a) Shaping of glass blanks

For molding the glass blank, for example, a press molding method can be used. By the press molding method, a circular glass blank can be obtained. Further, the down can be produced by a known production method such as a down drawing method, a redrawing method, a melting method, or a floating method. By appropriately shaping the plate-shaped glass blank produced by these known production methods, a disc-shaped glass substrate that constitutes a base member of a glass substrate for a magnetic disk can be obtained.

(b) Rough grinding

In the rough grinding, specifically, the main surfaces on both sides of the glass blank are ground by holding the glass blank in a holding hole provided in a holding member (carrier) attached to a known double-side grinding device provided with a planetary gear mechanism similar to the device shown in fig. 1 and 2. In this case, the carrier 30 described above may be used. As the abrasive, for example, free grains can be used. The rough grinding is performed so that the glass blank is roughly close to the target thickness of the plate material and the flatness of the main surface. Further, rough grinding is performed depending on the dimensional accuracy or surface roughness of the glass blank to be molded, and may not be performed in some cases.

(c) Shape working

Subsequently, shape processing is performed. In the shape processing, after a glass blank is molded, a circular hole is formed in the center of the glass blank by a known processing method, and a circular plate-shaped glass substrate perforated with the circular hole is obtained. After that, chamfering treatment of the end face of the glass substrate is performed. That is, the glass blank is processed in (a) to (c), whereby a disk-shaped glass substrate can be manufactured.

(d) End face grinding

Subsequently, the end face of the glass substrate is polished. The end face polishing is a process of polishing a glass substrate by supplying a polishing liquid containing free particles between a polishing brush and an end face of the glass substrate and relatively moving the polishing brush and the glass substrate. In the edge face polishing, the inner peripheral wall surface and the outer peripheral wall surface of the glass substrate are polished, and the inner peripheral wall surface and the outer peripheral wall surface are mirror surfaces.

(e) Fine grinding

Next, the main surface of the glass substrate is finish-ground. Preferably, the main surface of the glass substrate is ground by using a flat plate to which fixed grains are attached for finish grinding and using a double-side grinding apparatus of a planetary gear mechanism similar to the grinding apparatus shown in fig. 1 and 2. In this case, it is preferable to use a combination of a flat plate provided with fixed particles and a refrigerant instead of the combination of the free particles and the polishing pad. Specifically, the main surfaces of the glass substrate on both sides were ground by fixing grains in holding holes provided in the carrier 30 as holding members of the double-side grinding apparatus. The substitution amount according to grinding is, for example, about 10 μm to 200 μm. The load applied to the substrate by the flat plate is preferably 100 to 250g/cm²。

In the finish grinding of the present embodiment, the main surface of the glass substrate is ground by bringing the grinding surface including fixed grains into contact with the main surface of the glass substrate, but grinding may be performed using free grains.

(f) 1 st grinding

Next, the main surface of the glass substrate was subjected to the 1 st polishing. Specifically, the outer peripheral side wall surfaces of the glass substrates G are held in holding holes 32 provided in a carrier 30 of the polishing apparatus shown in fig. 1 and 2, and the main surfaces on both sides of the glass substrates G are polished. In the polishing 1, free particles were used, and a polishing pad attached to a flat plate was used. The 1 st polishing is for removing cracks and distortions remaining on the main surface when grinding is performed with fixed grains, for example. In the 1 st polishing, the shape of the end portion of the main surface is prevented from being excessively recessed or protruded, and the surface roughness of the main surface, for example, the arithmetic average roughness Ra, is reduced. The main surface is a mirror surface.

The free grains used in the first polishing are not particularly limited, and for example, cerium oxide grains, zirconium oxide grains, or the like are used.

The kind of the polishing pad is not particularly limited, and for example, a hard foamed urethane resin polishing material is used.

(g) Chemical strengthening

The glass substrate is chemically strengthened by a known method. The timing of performing the chemical strengthening can be appropriately determined. The chemical strengthening may be performed as needed, or may not be performed.

(h) Grinding No. 2 (Final grind)

Subsequently, the glass substrate after chemical strengthening is subjected to the 2 nd polishing. The purpose of the 2 nd polishing is to further reduce the roughness and the expansion of the main surface. In the 2 nd polishing, a double-side polishing apparatus of a planetary gear mechanism having the same configuration as that of the double-side polishing apparatus used in the 1 st polishing was used. Specifically, the outer peripheral side wall surfaces of the glass substrates G are held in holding holes 32 provided in a carrier 30 of the polishing apparatus shown in fig. 1 to 3, and the main surfaces on both sides of the glass substrates G are polished. This prevents the end portion of the main surface from being excessively recessed or protruding, and reduces the roughness of the main surface. In the 2 nd polishing, the type and particle size of the free particles and the hardness of the resin polished object of the polishing pad were different from those in the 1 st polishing.

As the free particles used for the 2 nd polishing, fine particles such as colloidal silica are used, for example. The polished glass substrate was cleaned to obtain a magnetic disk glass substrate.

The 2 nd polishing is not necessarily performed, but is preferably performed in order to further improve the level of surface irregularities of the main surface of the glass substrate. Thus, the glass substrate subjected to the 2 nd polishing was a magnetic disk glass substrate.

In at least one of the rough grinding, the finish grinding, the 1 st grinding and the 2 nd grinding performed by using the grinding apparatus or the polishing apparatus, an upper plate and a lower plate sandwiching the glass substrate G from the upper and lower directions are used. By setting the contour of the holding hole 32 so that the orientation direction wall surface portions 35 are positioned outside the circular arc shape inscribed in the contour of the inner peripheral wall surface of the holding hole 32 in the side wall surface of the holding hole 32 holding the glass substrate G used in the polishing process, the outer peripheral side wall surface of the glass substrate G in the polishing process is not abutted with the orientation direction wall surface portions 35 but abutted on both sides of the orientation direction wall surface portions 35 along the circumferential direction of the holding hole 32. Preferably, the wall surfaces of the orientation direction wall surface portion 35 of the holding hole 32 on both sides in the circumferential direction of the holding hole 32 form a convex 1 st curved surface 37 shown in fig. 4, a flat surface 38 shown in (a) to (c) of fig. 8, or a 2 nd curved surface 39 shown in fig. 9. The outer peripheral side wall surface of the glass substrate G during the polishing process is in contact with the 1 st curved surface 37, the flat surface 38, or the 2 nd curved surface 39, but is not in contact with the alignment direction wall surface portion 35. Therefore, the occurrence of scratches on the outer peripheral side wall surface of the glass substrate G can be suppressed, and the formation of defects on the main surface of the glass substrate G can be suppressed.

Embodiment 2

Next, the polishing carrier, the method for manufacturing the polishing carrier, and the method for manufacturing the magnetic disk substrate according to embodiment 2 will be described in detail.

As a result of the study by the present inventors, it has been found that when the polishing treatment is performed using the carrier described in patent document 1, foreign matter adheres to the main surface of the glass substrate, and the main surface is contaminated or scratched (minute scratches). Specifically, it was found that after the polishing treatment using the carrier on which the holding hole buffer regions were formed, the strength in the vicinity of the inner wall surfaces of the holding holes was reduced, and a part of the resin material constituting the carrier was detached (lacked), and foreign matter was attached to the main surface of the glass substrate after the polishing treatment, thereby contaminating the main surface. In addition, scratches may be formed on the main surface of the glass substrate. After the present inventors have studied for some time, the following reasons have been found: in the ring-shaped region outside the inner wall surface of the holding hole, the glass fibers are completely removed, the reinforcing effect by the glass cloth is lost, the strength in the vicinity of the inner wall surface of the holding hole is reduced, and in the polishing process, the glass substrate repeatedly collides or is pressed against the holding hole buffer region of the carrier, so that a part of the resin material constituting the holding hole buffer region is dropped and contaminated and enters between the glass substrate and the flat plate, whereby the main surface of the glass substrate is contaminated or scratched. Further, as a result of repeating experiments, the following aspects of the carrier for polishing, the method for manufacturing the carrier for polishing, and the method for manufacturing the substrate for a magnetic disk were invented.

(Carrier for polishing treatment)

Fig. 10 shows a carrier 1 of the present embodiment.

The carrier 1 is used for holding a glass substrate as a grinding target or a polishing target in a grinding process (a rough grinding process and a finish grinding process) and a polishing process (a 1 st polishing process and a 2 nd polishing process) to be described later. In the present embodiment, the grinding process is simply referred to as a polishing process, and the grinding process is understood to be a concept included therein. The carrier 1 has a plurality of holding holes 3 for holding glass substrates.

The carrier 1 includes a resin-impregnated substrate having a glass cloth in which a plurality of glass fibers are arranged in any of 2 orientation directions and a resin material impregnated in the glass cloth, and the glass cloth reinforces the carrier 1.

The glass cloth is not particularly limited, and a known glass cloth can be used, and for example, a cloth obtained by plain-weaving a plurality of glass yarns as bundles of glass fibers can be used. In the plain-woven glass fabric, a plurality of glass yarns are oriented in 2 orientation directions orthogonal to each other. In the present embodiment, the term "orthogonal" includes not only the case where the 2 alignment directions form 90 °, but also the case where the 2 alignment directions form substantially 90 ° (e.g., 70 to 110 °, 78.75 to 101.25 °, 80 to 100 °). The 2 alignment directions may be orthogonal to each other or may be non-orthogonal to each other (for example, directions forming 60 ° or 120 ° with each other). The material of the glass fiber is not particularly limited, and for example, aluminosilicate glass is used.

In the resin-impregnated substrate, the resin material is impregnated into the glass cloth so as to surround each glass fiber, but a part of the glass fibers may be directly connected to each other. The resin material is not particularly limited, and for example, a thermosetting resin such as an epoxy resin or a phenol resin is used. The resin-impregnated substrate is produced by a known method, for example, by the following method: a resin material is impregnated into a glass cloth, and a plurality of prepregs (for example, 5 prepregs) obtained by drying the resin material are stacked so that the orientation directions of the prepregs are aligned, and are pressure-bonded. The diameter of the glass fiber is not particularly limited, and is, for example, 5 to 10 μm. The plain-woven glass fabric is not particularly limited, but the thickness of the glass yarn (the width of the glass yarn along the planar direction of the carrier) is, for example, 200 to 700 μm, the thickness of the glass yarn (the width of the glass yarn along the thickness direction of the plate material of the carrier) is, for example, 40 to 90 μm, and the interval (gap) between the glass yarns is, for example, 300 to 700 μm.

The carrier 1 of the present embodiment is formed of a composite material including glass fibers and a resin material oriented in at least one direction, as in the carrier 30 of embodiment 1, and has holding holes 3 for holding a disk-shaped substrate when the substrate is polished by sandwiching the substrate between an upper plate and a lower plate on a pair of main surfaces of the substrate. The holding hole 3 has a 1 st wall portion configured to bring the substrate into contact with the fibers in a state where the substrate is held by the holding hole 3 and a 2 nd wall portion (a 1 st inner wall surface 5a and a 2 nd inner wall surface 5b described later) configured to not bring the substrate into contact with the fibers, on the periphery of an inner wall surface (inner peripheral wall surface) 5 of the holding hole 3. The 2 nd wall portion is formed at a portion facing the orientation direction of the fibers including one direction in the inner peripheral wall surface of the holding hole 3. Further, the carrier 1 of embodiment 2 is characterized in that a fiber-absent region (the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 described later) which is provided on the outside of the radial direction of the holding hole with respect to the 2 nd wall portion and in which no fiber is present in the orientation direction is arranged in the annular region 7 extending from the inner peripheral wall surface of the holding hole 3 to the outside of the radial direction of the holding hole 3.

As shown in fig. 12, in the annular region 7 extending outward from the inner wall surface 5 of the holding hole 3, the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 of the carrier 1 are alternately arranged in the circumferential direction of the holding hole 3 while being spaced apart from each other. Fig. 12 is a view showing the holding hole 3 of the carrier 1 focusing on the annular region 7. In fig. 12, for convenience of explanation, 1 glass fiber regarded as 1 glass yarn is shown instead of the glass yarn constituting the glass woven fabric, and the width of the annular region 7 (the length along the length in the radial direction of the holding hole 3) is shown as being enlarged. In the present embodiment, the inner wall surface of the holding hole means an inner wall surface defining the holding hole, except for the case described in advance. The term "outside of the inner wall surface" or "extending outward from the inner wall surface" means a portion of the composite material constituting the carrier, which extends from the inner wall surface along the planar direction of the carrier 1 to a direction extending outward in the radial direction of the holding hole 3 from the center of the holding hole 3, in other words, a predetermined width exists outward in the radial direction of the holding hole 3 from the inner wall surface.

The width (length along the radial direction of the holding hole 3) of the annular region 7 is not particularly limited, and is, for example, 2 to 10 μm. The 1 st strengthened region 11 is strengthened only by the 1 st glass fiber 21 oriented in one direction (X direction) of the 2 orientation directions (X direction and Y direction shown in fig. 12). In addition, the 2 nd reinforcing region 13 is reinforced only by the 2 nd glass fiber oriented in the other direction (Y direction) of the orientation direction. In other words, in the 1 st reinforcing region 11, only the 2 nd glass fiber 23 is removed, and in the 2 nd reinforcing region 13, only the 1 st glass fiber 21 is removed. The glass fibers (21,23) for reinforcing the respective reinforcing regions (11,13) are not limited to those shown in fig. 12 in the respective reinforcing regions (11,13), and there are 1 or more glass fibers depending on the diameter of the glass fibers. In the 1 st reinforcing region 11, the 2 nd glass fibers 23 are removed, and a portion made of a resin material having a plurality of recesses (not shown) each having a shape extending in an orientation direction (a direction substantially perpendicular to the inner wall surface) to which the 2 nd glass fibers 23 face is formed. In the 2 nd reinforcing region 13, the 1 st glass fiber 21 is removed to form a portion similarly made of a resin material having a plurality of recesses (not shown). In the present embodiment, the case of reinforcing only with the 2 nd glass fiber includes a case where the 2 nd glass fiber is partially absent in the 1 st reinforcing region. Similarly, the case of reinforcing only with the 1 st glass fiber includes a case る where the 1 st glass fiber is partially absent in the 2 nd reinforcing region. From tens to thousands of glass fibers are bundled to form a yarn. In the present embodiment, when a yarn oriented in the lateral direction (direction substantially perpendicular to the orientation direction of the glass fibers) is present on the surface of the inner wall surface, most of the fibrils remain even if part of the fibrils (1 glass fiber) on the surface is etched. Therefore, the strength of the carrier is almost maintained.

As shown in fig. 13, the positions of the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 in the annular region 7 are preferably set as follows: the reinforcing regions (11,13) are arranged at substantially equal intervals in the circumferential direction, and are preferably located at positions in the range of ± 20 ° (for example, ± 11.25 °, ± 10 °) around the center of the holding hole (3) (around the center portion) in the directions forming 0 °, 90 °, 180 °, 270 °, and with respect to the directions forming 0 °, 90 °, 180 °, 270 ° around the center of the holding hole (3). Thus, the glass fibers substantially orthogonal to the inner wall surface 5 of the holding hole 3 can be reliably removed from the reinforcing regions (11,13), and the glass fibers can be secured in the other annular region 7 (in the annular region 7, the region other than the reinforcing regions (11, 13)). Fig. 13 shows the holding hole 3 of the carrier 1 focusing on the annular region 7.

In the present embodiment, the annular region 7 includes two 1 st reinforcing regions 11 and two 2 nd reinforcing regions 13, and the number of the 1 st reinforcing regions and the 2 nd reinforcing regions is determined according to the angle formed by the 2 orientation directions. In addition, the portion 15 of the annular region 7 other than the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 included in the 1 annular region 7 is reinforced by both the 1 st glass yarn and the 2 nd glass yarn, as in the portion of the carrier 1 outside the annular region 7.

The 1 st reinforcing region 11 is provided on the outer side of the 1 st inner wall surface 5a facing the orientation direction (oriented direction) of the 2 nd glass fiber 23 in the inner wall surface 5 of the holding hole 3. In addition, the 2 nd reinforcing region 13 is provided on the outer side of the 2 nd inner wall surface 5b facing the orientation direction (facing the orientation direction) of the 1 st glass fiber 21 in the inner wall surface 5. The portion of the inner wall surface 5 of the holding hole 3 other than the 1 st inner wall surface 5a and the 2 nd inner wall surface 5b (both 2 nd wall portions) is the 1 st wall portion. In other words, the 1 st inner wall surface 5a and the 2 nd inner wall surface 5b of the inner wall surface 5 of the holding hole 3 are fiber contact surfaces configured such that the glass substrate does not contact the glass fibers in a state where the glass substrate is held in the holding hole 3, and portions other than the 1 st inner wall surface 5a and the 2 nd inner wall surface 5b are fiber contact surfaces configured such that the glass substrate contacts the glass fibers in the above state.

In the present embodiment, the inner wall portion facing the orientation direction means that the inner wall portion faces the orientation direction, in other words, means that the inner wall portion faces the orientation direction or the normal direction of the inner wall portion faces the orientation direction or the fibers are exposed or projected (projected) from the inner wall portion of the plate material in the vertical direction in the process of producing the carrier. The vertical direction mentioned here is a direction within a range of ± 20 ° (for example, ± 11.25 °, ± 10 °) in the plane direction of the carrier with respect to the normal line direction of the inner wall portion. When the inner wall portion is directed in the orientation direction, the case where the wiring direction of the inner wall portion at the position of the inner wall portion intersecting with the orientation direction is orthogonal to the orientation direction (center line) includes the case where the wiring direction intersects with the orientation direction within an angular range of ± 20 ° (for example, ± 11.25 °) around the orthogonal direction. In other words, the normal direction of the inner wall portion at the position of the inner wall portion intersecting the orientation direction may coincide with the orientation direction, and may also coincide with the orientation direction within the above-described angular range around the orientation direction. The orientation direction of the glass fibers facing the inner wall portion indicates a direction in which the glass fibers protrude substantially perpendicularly to the wire connecting direction of the inner wall portion.

In the carrier 1, the 1 st reinforcing region 11 is formed so that the ends of the 2 nd glass fibers 23 do not reach the inner wall surface 5 of the holding hole 3, and the 2 nd reinforcing region 13 is formed so that the ends of the 1 st glass fibers 21 do not reach the inner wall surface 5 of the holding hole 3. In other words, a part of the range of the 1 st reinforcing region 11 is determined by the end of the 2 nd glass fiber 23, and a part of the range of the 2 nd reinforcing region 13 is determined by the end of the 1 st glass fiber 21.

When the glass substrate is polished using the carrier 1 described above, there are no glass fibers protruding (flying) from the inner wall surface 5 of the holding hole 3 in a direction substantially perpendicular thereto, and therefore, it is possible to prevent the end surface of the glass substrate from being scratched during the polishing process. In addition, the glass fibers oriented in a direction different from the glass fibers oriented in a direction substantially perpendicular to the inner wall surface 5 are present in the 1 st reinforcing region 11 and the 2 nd reinforcing region 13, thereby securing the strength in the vicinity of the inner wall surface 5 of the holding hole 3. Therefore, it is possible to prevent the portion near the inner wall surface 5 made of the resin material having a plurality of recesses from being peeled by external force (collision, pressure contact, friction, or the like with respect to the inner wall surface of the glass substrate) in the polishing process, and from being detached from the carrier. Therefore, the resin material can be prevented from being contaminated, entering between the glass substrate and the flat plate, adhering to the main surface of the glass substrate, or causing scratches on the main surface of the glass substrate.

Further, since the glass fibers present in the 1 st strengthening region and the 2 nd strengthening region are oriented in a direction substantially perpendicular to the inner wall surface (for example, a direction substantially parallel thereto), even if the glass fibers are brought into contact with the end surfaces of the glass substrate during the polishing process, the glass fibers are brought into contact with the end surfaces of the glass substrate so as to slide with respect to the glass fibers and rotate, and therefore, the glass fibers are less likely to be scratched.

In the carrier 1, the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 need not be provided on the inner wall surfaces 5 of all the holding holes 3 included in the carrier 1, and may be provided only on a part of the inner wall surfaces 5 of the holding holes 3. In this case, the polishing process is performed while holding the glass substrate only in the holding hole 3 provided with the 1 st strengthening region 11 and the 2 nd strengthening region 13.

(method of producing polishing Carrier)

Next, a method for producing the polishing carrier will be described.

The method for manufacturing a polishing carrier according to the present embodiment includes a cutting process (step 1) and an etching process (step 2).

In the cutting process, the holding hole 3 is formed in the resin-impregnated substrate. Specifically, the resin-impregnated substrate was cut by an end mill to produce the outer peripheral shape of the carrier and the holding hole shown in fig. 10. Fig. 11 is a perspective view showing the carrier shown in fig. 10 focusing on one holding hole. In fig. 10, for convenience of explanation, the outer shape of the carrier is shown as a different form from that of fig. 11. At this time, in the resin-impregnated substrate, the glass fibers of the glass fabric are cut along the outer peripheral shape of the carrier and the holding holes. In the cutting process, when a plurality of resin-impregnated substrates are arranged in a stacked manner in the etching process, it is preferable that the holding holes 3 are not formed so that the orientation direction of the glass fibers is aligned between the resin-impregnated substrates, from the viewpoint of providing a mask material described later and easily applying an etchant. For example, after resin-impregnated substrates (plate materials) are stacked in alignment with the orientation direction, holding holes may be formed through the plurality of resin-impregnated substrates. This improves productivity. After the cutting process is performed, a deburring process may be performed.

In the etching treatment, the resin-impregnated substrate on which the holding holes 3 are formed is at least etched to produce a carrier. For example, after etching, the carrier is produced by washing, drying, or the like. In the etching treatment, specifically, the glass fibers exposed in the orientation direction are etched at inner wall portions (portions of the inner wall surfaces indicated by

reference numerals

5a and 5b in the carrier shown in fig. 12) of the inner wall surface 5 of the holding hole 3 in any direction toward the orientation direction of the glass fibers, so that a reinforcing region is formed in an annular region 7 extending outward from the inner wall surface 5 of the holding hole 3 of the carrier, the reinforcing region being reinforced only by the glass fibers in the orientation direction different from the orientation direction of the etched glass fibers. In short, as shown in fig. 12, the 1 st reinforcing region 11 and the 2 nd reinforcing region 13 are formed by etching the 2 nd glass fiber 23 exposed on the 1 st inner wall surface 5a and the 1 st glass fiber 21 exposed on the 2 nd inner wall surface 5 b. In the present embodiment, the end of the glass fiber is positioned on the inner wall surface, and the end protrudes inward from the inner wall surface when simply referred to as exposure.

In the etching treatment, the resin-impregnated substrate to be cut is immersed in, for example, an etchant, and the glass fibers exposed by the cutting are etched. In the present embodiment, only the fibers protruding (flying) in the vertical direction in a part of the inner wall surface (the part constituting the 2 nd wall portion) among the fibers included in the resin-impregnated substrate are removed, and therefore, the fibers woven in most of the inner wall surface, that is, the fibers oriented in any orientation direction are left in a state of being left, and a decrease in the strength of the carrier can be prevented. The etchant used for the etching treatment by impregnation is not particularly limited as long as it is an etchant having etching properties to the fibers. In the case of etching glass fibers, for example, an etchant containing a fluorine acid or a fluorine compound is preferably used. Examples of the etchant containing hydrofluoric acid include, in addition to hydrofluoric acid, fluorosilicic acid and the like. Examples of the fluorine compound may include ammonium fluoride (NH)₄F) Ammonium hydrogen fluoride (NH)₅F₂) And the like. Further, a mixed acid obtained by mixing a strong acid such as hydrofluoric acid, sulfuric acid, or nitric acid may be used as the etchant, and a viscosity adjuster, a solvent, or the like may be further included. The above-mentioned substances may be mixed appropriately and used. In the case where the resin-impregnated material is impregnated with an etchant to be etched, for example, an etchant containing hydrofluoric acid and sulfuric acid may be used. In this case, it is preferable that the concentration of the fluoric acid is about 0.01 to 2.0% and the concentration of the sulfuric acid is about 0.02 to 4.0%. In the present embodiment,% represents mass%. The impregnation time may be appropriately determined depending on the amount of glass fiber etched (the length in the radial direction of the 1 st reinforcing region 11 and the 2 nd reinforcing region 13) and the concentration of the etchant, and is preferably less than 60 minutes, for example. If the concentration of the etchant is too high or the time for which the etchant is left is too long, the fibers are removed to a necessary extent, and the resin portion is damaged by etching, whereby the fibers are damagedThe strength of the inner wall surface of the holding hole is reduced, and the resin on the inner wall surface is easily peeled off during polishing or grinding.

The etching treatment is not limited to the one by impregnation with the seed, and may be performed by applying an etchant to the resin-impregnated material. The coating may be performed by using a coating means such as a brush, or may be performed by spraying with a sprayer. As the etchant in this case, for example, an aqueous solution of hydrofluoric acid, ammonium bifluoride or the like is used. The concentration of the etchant and the standing time of the resin-impregnated material after application may be appropriately set, but from the viewpoint of maintaining the strength of the inner wall surface of the holding hole, for example, the concentration of the etchant is preferably 0.1 to 20 wt%. Also, the standing time after coating is preferably less than 60 minutes.

The etching treatment may be performed by dipping, coating, or spraying, in addition to the above-described impregnation and coating.

In the etching process, a mask material (not shown) may be provided in a portion 15 (see fig. 12) of the annular region 7 other than the portion where the reinforcing region is formed, before the etching, and the mask material may be removed after the etching. This protects the portion other than the portion where the reinforcing region is formed from the etchant, and prevents the glass fiber from being etched in this portion. The carrier 1 can be prepared by impregnating with a masking agent, for example, by spraying. As the mask material, for example, a tape or a resin layer is used. As the resin of the resin layer, polytetrafluoroethylene, epoxy resin, or the like is used. In addition, since creases corresponding to the orientation direction of the glass fibers usually appear on the main surface of the carrier with respect to the positions on the inner wall surface where the mask material is provided, these directions can be visually confirmed and set accordingly. In the case of impregnation, the main surface of the mask support is preferably impregnated with a resin or the like. Further, as the mask, a plate material (resin-impregnated substrate) of another composite material may be laminated. By stacking, carrier manufacturing efficiency can be improved and cost can be reduced.

In the etching treatment, the resin-impregnated substrate may be etched by applying the etchant to a portion where the reinforcing region is formed in the annular region 7, instead of the impregnation with the etchant described above. This allows the glass fibers to be etched only in the portion of the annular region 7 of the carrier that is to be formed as the reinforcing region. The position to which the etchant is applied can be set by visually checking the orientation direction of the glass fibers by a crease appearing on the main surface of the carrier, as in the method of checking the position to provide the mask material.

In the etching treatment, it is preferable that before the etching, a resin-impregnated substrate (the 1 st plate material) and 1 or more other substrates having holding holes formed at positions corresponding to the positions of the resin-impregnated substrate where the holding holes 3 are formed are arranged so as to overlap in the plate material thickness direction. In this way, the main surface of the resin-impregnated substrate is prevented from being exposed to the etchant during etching, and the strength of the carrier is prevented from being reduced by etching the glass fibers of the main surface of the resin-impregnated substrate. The other substrate may be a resin-impregnated substrate (2 nd plate material) for manufacturing the same carrier as the carrier 1, or may be a dummy substrate used for protecting the main surface of the 1 st plate material. The dummy substrate may be disposed on both sides of the 1 st plate member so as to sandwich the 1 st plate member, or the 1 st plate member may be disposed on both sides of the dummy substrate. The other substrate and the 1 st plate material are bonded during etching according to a temporary adhesive or the like for temporarily fixing each other.

Preferably, when a plurality of resin-impregnated substrates (the 1 st plate material and the 2 nd plate material) are arranged in a stacked manner, the orientation direction of the glass fibers is aligned between the resin-impregnated substrates. When the positions of the holding holes 3 formed with respect to the orientation direction of the glass fibers are the same between the plurality of resin-impregnated substrates, the step of providing the above-described mask material and applying the etchant in a laminated state can be easily performed.

The polishing carrier of the above embodiment or the carrier produced by the method for producing a polishing carrier is used, for example, in a method for producing a magnetic disk substrate described later, and may be used, for example, in the production of a substrate other than a glass substrate such as an aluminum substrate or a silicon wafer.

The polishing carrier or the carrier produced by the method for producing a polishing carrier described above can be used not only for polishing but also for grinding. For example, the method for manufacturing a magnetic disk substrate described later can be used in the whole process of grinding or polishing the main surface by planetary gear motion, such as rough grinding, finish grinding, 1 st polishing, and 2 nd polishing.

(method of manufacturing magnetic disk substrate)

Next, a method for manufacturing a magnetic disk substrate according to the present embodiment will be described.

The manufacturing method comprises the following grinding treatment: the main surface of the substrate is polished while holding the glass substrate in the polishing carrier described above or the polishing carrier produced by the method for producing the polishing carrier. In the following description, the term "carrier" refers to the polishing carrier described above or a carrier produced by the method for producing a polishing carrier.

The outline of the manufacturing process performed in the present embodiment is described below: first, a molding process for forming a plate-like glass blank having a pair of main surfaces is performed. The glass blank becomes a material of a glass substrate for a magnetic disk. Next, the glass blank is subjected to a rough grinding process. Thereafter, the glass blank is subjected to shape processing to form a glass substrate, and further subjected to end face polishing. Thereafter, the glass substrate was subjected to finish grinding using fixed grains. Thereafter, the glass substrate is subjected to the 1 st polishing process and the 2 nd polishing process. In the present embodiment, the process is performed by the above-described flow, but the type of the above-described flow and process is not limited, and the above-described process may be appropriately omitted as necessary. Next, the above-described respective processes will be described.

(a) Shaping treatment of glass blank

In the molding treatment, for example, a press molding method is used for molding. A disk-shaped glass blank is obtained by press molding. Instead of the pressing method, a known molding method such as a down drawing method, a redrawing method, or a melting method may be used to manufacture a glass blank. The plate-shaped glass blank obtained by these methods is subjected to shape processing described later as appropriate, to obtain a disk-shaped glass substrate serving as a base member of a glass substrate for a magnetic disk.

(b) Rough grinding treatment

Subsequently, rough grinding treatment is performed. In the rough grinding process, the glass blank is held by a carrier of a double-side grinding apparatus, and main surfaces of both sides of the glass blank are ground. Specifically, the glass blank is held in a holding hole provided in a carrier, and is sandwiched between an upper plate and a lower plate, and either or both of the upper plate and the lower plate is moved while a grinding fluid including a grinding agent is supplied, whereby the glass substrate and each of the plates are relatively moved, and both main surfaces of the glass substrate are ground. As the abrasive, for example, free grains are used. In the rough grinding process, the glass blank is ground to approximately approximate the thickness dimension of the target plate material and the flatness of the main surface. In addition, the rough grinding process is performed according to the dimensional accuracy or surface roughness of the glass blank to be molded, and the rough grinding process may be appropriately omitted.

(c) Shape processing treatment

Subsequently, shape processing is performed. In the shape processing, a circular hole is formed in the glass blank by a known processing method, and a circular plate-shaped glass substrate having a circular hole is obtained. After that, chamfering treatment of the end face of the glass substrate is performed. Both end faces of the glass substrate on the inner peripheral side and the outer peripheral side are chamfered. By performing the chamfering process, a side wall surface orthogonal to the main surface and a chamfered surface (via surface) for connecting the side wall surface and the main surface are formed on the end surface of the glass substrate.

(d) End face grinding treatment

Subsequently, the end face of the glass substrate is polished. In the end face polishing process, a polishing liquid containing free particles is supplied between the polishing brush and the end face of the glass substrate, and the polishing brush and the glass substrate are moved relatively in the thickness direction of the glass substrate to polish the glass substrate. The end faces on the inner and outer peripheral sides of the glass substrate are polished by the end face polishing process to be in a mirror surface state.

(e) Finish grinding process

Next, the main surface of the glass substrate is subjected to finish grinding processing. In the finish grinding process, it is preferable to grind the main surface of the glass substrate using a double-surface grinding apparatus in which fixed particles are stuck to a flat plate. Specifically, both main surfaces of the glass substrate were ground almost in the same manner as in the above-described rough grinding treatment except for the point where grinding was performed using fixed grains instead of the above-described free grains. The glass substrate is held on the carrier of the above embodiment, and ground by planetary gear movement in the double-side grinding apparatus. In this carrier, since there are no glass fibers oriented in the direction near the inner wall portion facing the direction of orientation of the glass fibers, the end surface of the glass substrate is prevented from being scratched in the finish grinding process. The carrier is reinforced by the glass fibers having a different orientation direction from the glass fibers, and therefore, the strength of the carrier in the vicinity of the inner wall surface of the holding hole is ensured, and the occurrence of contamination due to the resin material is suppressed. In the finish grinding process, the main surface of the glass substrate is ground by bringing the grinding surface of the flat plate to which the fixed grains are attached into contact with the main surface of the glass substrate, or alternatively, grinding may be performed using free grains.

(f) 1 st grinding treatment

Next, the first polishing process is performed on the main surface of the glass substrate. In the first polishing process, the glass substrate was held on a carrier and the main surfaces of the glass substrate on both sides were polished using a known double-side polishing apparatus. In the polishing process 1, using free particles, a polishing pad attached to a flat plate was brought into contact with the main surface of the glass substrate and polished. The free grains are not particularly limited, and for example, grains of cerium oxide or grains of zirconium oxide are used. In the polishing process 1, for example, when the polishing is performed using fixed grains, cracks and distortions remaining in the main surface and fine surface irregularities generated in the main surface by the crystallization process are removed. By appropriately adjusting the substitution amount, the shape of the end portion of the main surface is prevented from being excessively recessed or protruding, and the surface roughness of the main surface, such as the arithmetic average roughness Ra, can be reduced.

(g) 2 nd grinding (mirror grinding) treatment

Subsequently, the 2 nd polishing process is performed. The purpose of the 2 nd polishing process is to perform mirror polishing of the main surface. In the 2 nd polishing treatment, the same double-side polishing apparatus and polishing method as those used in the 1 st polishing treatment can be used, but it is preferable to use polishing grains having a smaller grain size than polishing grains used in the 1 st polishing treatment. Thus, the shape of the end portion of the main surface is prevented from being excessively recessed or protruding, and the roughness of the main surface can be reduced.

A known double-side polishing apparatus can be used for the second polishing process 2. The device includes: a pair of upper and lower plates; an inner gear clamped between the upper flat plate and the lower flat plate; a sun gear provided on the lower plate; and a plurality of carriers engaged with the internal gear and the sun gear. A polishing pad is attached to each flat plate. In this apparatus, a glass substrate is held between an upper plate and a lower plate, and the upper plate and the lower plate are rotated in opposite directions relative to each other, so that a carrier holding the glass substrate revolves while rotating on its axis, and a planetary gear motion is performed. Thus, the glass substrate and the polishing pad are relatively moved, and the main surface of the glass substrate is polished. The above-described machining device and machining mechanism can be used in the grinding and polishing as well.

After the 2 nd polishing process, the glass substrate was removed from the double-side polishing apparatus for each carrier and washed, and the manufacturing process was completed. While the above-described manufacturing process is being repeated, the same polishing liquid is used in the 2 nd polishing process.

In the method for manufacturing a magnetic disk substrate according to the present embodiment, since the polishing treatment is performed using the carrier described above, the occurrence of scratches on the end surfaces of the glass substrate during the polishing treatment is prevented, contamination by the resin material is suppressed, and contamination and scratches on the main surfaces of the glass substrate are suppressed.

(example corresponding to embodiment 1)

Carriers were produced that had the specifications described in embodiment 1 in addition to the specifications for the wall part 1 described below (examples 1 to 4, comparative examples 1 and 2).

Example 1: as shown in FIG. 4, in the case where 1 holding hole includes 8 convex-shaped 1 st curved surfaces (notches)

Example 2: in the case where 1 holding hole includes 6 notches

Example 3: as shown in FIG. 6 (a), in the case where 1 holding hole includes 10 notches

Example 4: as shown in FIG. 8 (b), in the case where 1 holding hole includes 8 planes

Comparative example 1: case where the first wall part 1 is not provided (case where a simple circular holding hole is formed without etching)

Comparative example 2: in comparative example 1, the plate material of the portion where the holding hole was formed was subjected to etching treatment over the entire circumference, so that there was no glass fiber over the entire circumference of the holding hole

In the notches of examples 1 to 3, the maximum protrusion amount was 2mm, the curvature radius R was 30mm, and the maximum protrusion amount of the flat surface of example 4 (the protrusion amount in the radial direction of a virtual circle that extends from a virtual circle that is a part of the wall surface portion of the orientation direction wall surface portion toward the center direction of the virtual circle) was 2 mm. The etching treatment of comparative example 2 was performed in the same manner as in comparative example 5 described later.

< grinding test >

Using the carriers of examples 1 to 4 and comparative examples 1 and 2, and a double-side polishing apparatus having a planetary gear mechanism, the load applied to the substrate was 100g/cm²A magnetic disk glass substrate was produced based on embodiment 1 except that the glass substrate was subjected to polishing treatment 2 of embodiment 1 under polishing conditions of a plate rotation speed of 25rpm and a polishing time of 60 minutes. An aluminosilicate glass substrate having an outer diameter of 2.5 inches was used as the glass substrate, and the plate thickness was finally set to 0.653 mm.

After the 2 nd polishing treatment, the glass substrate was cleaned and dried, and then defects on the main surface of the glass substrate were detected using a laser type surface inspection apparatus, and for 20 defects per substrate randomly selected from among them, SEM observation and elemental analysis were further performed, and the number of resinous foreign matter (number of defects) was measured. If the number of the resin foreign matter is 1 or less per substrate, there is no problem in practical use. The scratches (recessed defects) on the side wall surfaces of the end surfaces were observed visually or with a microscope using a spotlight on a dark screen. When the end face was scratched, bright spots were observed continuously over the entire circumference at regular intervals of about 1mm or less. The results are shown in Table 1.

TABLE 1

As shown in table 1, when the polishing treatment was performed using the carrier having the 1 st wall portion described in embodiment 1 (examples 1 to 4), the number of defects in the main surface was smaller than that when the polishing treatment was performed using the carrier not having such 1 st wall portion (comparative examples 1 and 2).

Further, as a result of visual observation of the side wall surface, it is considered that the flaw caused by the friction with the carrier was not found in any of the glass substrates except comparative example 1.

< grinding test >

Next, a magnetic disk glass substrate was produced based on embodiment 1, except that the carriers of examples 1 to 4 and comparative examples 1 and 2 were used, and a double-side grinding apparatus provided with a planetary gear mechanism was used to perform finish grinding. grains of grinding pad were stuck and fixed to a flat plate, and the load on the substrate was 150g/cm²The plate rotation speed was 25rpm, and the processing time was 60 minutes, 100 lots of experiments were performed with replacement of the substrate without replacing the carrier (examples 5 to 8 and comparative examples 3 and 4, respectively), and after cleaning the glass substrates of the 1 st lot and the 100 th lot, scratches on the side wall surfaces were detected. In addition, 100 sheets were processed per batch, and 5 carriers capable of holding 20 sheets were used per batch, and therefore, each carrier was usedIn the experimental examples, a total of 10000 glass substrates were produced.

TABLE 2

In comparative examples 3 and 4, no scratch was observed in the 100 th batch. Then, as a result of detecting the inner wall surface of the holding hole of the carrier after processing of 100 batches, the glass fiber protruding vertically was observed. That is, it is thought that, of the portions including the inner walls of the holding holes, only the portions made of the resin material are peeled off during grinding, and the glass fibers protruding vertically are exposed, thereby causing scratches on the end faces of the glass substrates. In contrast, in examples 5 to 8, no flaw was observed on the side wall surface of the glass substrate in any of the 1 st batch and the 100 th batch.

(example corresponding to embodiment 2)

A resin-impregnated substrate was prepared by the following steps: a resin-impregnated substrate having a thickness of 0.5mm was obtained by impregnating a plain-woven glass fabric with an epoxy resin, drying and curing the impregnated fabric to obtain a prepreg having a thickness of 0.1mm, stacking 5 sheets of the prepreg so that the orientation directions of the glass fibers are aligned, and pressure-bonding the stacked sheets. The resin-impregnated substrate was cut by an end mill and deburred to have the shape shown in fig. 10. In order to form the portions of the circumferential direction regions of the 1 st reinforcing region 11 and the 2 nd reinforcing region 13, which form the inner wall surface of the holding hole of the resin-impregnated substrate subjected to cutting, in regions in which circumferential direction positions of 0 °, 90 °, 180 °, and 270 ° are within ± 11.25 ° respectively around the center of the holding hole 3 with respect to any one of the reinforcing regions, a liquid (etchant) in which ammonium bifluoride and glycerin for viscosity adjustment are mixed at a concentration of 20% is applied and left for 10 minutes, and only the applied portion is subjected to etching treatment of glass. After the etching treatment was performed, the resin-impregnated substrate was washed with water, thereby obtaining a support (example 9). A carrier was produced in the same manner as in example 9, except that the standing time (etching time) after coating was 20 minutes (example 10).

Comparative example

A carrier was obtained in the same procedure as in example 9 except that the resin-impregnated substrate cut by cutting was immersed for 15 minutes in an etchant composed of hydrofluoric acid having a concentration of 1.3% and sulfuric acid having a concentration of 2.6% during the etching treatment (comparative example 5). A carrier was obtained in the same procedure as in example 9 except that the etching agent was applied to the entire circumferential region of the inner wall surface of the holding hole (comparative example 6).

< Observation of Ring-shaped region >

As a result of observing the inner wall surfaces of the holding holes of the carriers of example 9 and comparative examples 5 and 6 using an optical microscope and a laser microscope, in the ring-shaped region of the carrier of example 9, a region where only the 1 st glass fiber was removed and the 2 nd glass fiber was left and a region where only the 2 nd glass fiber was removed and the 1 st glass fiber was left were alternately formed at intervals of substantially 90 ° in the circumferential direction of the inner wall surface. In addition, in the annular regions of the carriers of comparative examples 5 and 6, regions where all of the 1 st glass fiber and the 2 nd glass fiber were removed were formed over the entire circumference.

< grinding test >

Except that the carriers of examples 9 and 10 and comparative examples 5 and 6 were used and a double-side polishing apparatus equipped with a planetary gear mechanism was used, the load on the substrate was 100g/cm²A magnetic disk glass substrate was produced based on embodiment 2 above, except that the glass substrate was subjected to polishing treatment 2 of embodiment 2 above under polishing conditions of a platen rotation speed of 25rpm and a polishing time of 60 minutes. As the glass substrate, an aluminosilicate glass substrate having an outer diameter of 2.5 inches was used, and the thickness of the finally obtained plate was 0.653 mm.

After the 2 nd polishing treatment, the glass substrate was cleaned and dried, and then defects on the main surface of the glass substrate were detected using a laser type surface inspection apparatus, and the number of resinous foreign matter (number of defects) was measured by performing SEM observation and elemental analysis on 20 defects per substrate randomly selected from among the defects. If the number of the resin foreign matter is 1 or less per substrate, there is no problem in practical use. The scratches (recessed defects) on the side wall surfaces of the end surfaces were observed visually or with a microscope using a spotlight on a dark screen. When the end face is scratched, bright spots are observed continuously over the entire circumference at a constant interval of about 1mm or less. The results are shown in Table 3.

TABLE 3

As shown in table 3, when the polishing treatment was performed using the carriers having the strengthened regions strengthened with only one of the glass fibers oriented in the 2 orientation directions (examples 9 and 10), the number of defects in the main surface was smaller than that in the cases where the polishing treatment was performed using the carriers having the regions where all of the glass fibers oriented in the 2 orientation directions were removed (comparative examples 5 and 6), and adverse effects on the main surface of the glass substrate could be avoided.

Further, as a result of visual observation of the side wall surface, no flaw was observed in any of the glass substrates, which would be caused by friction with the carrier, but as a result of observation of the side wall surface using a laser type surface inspection apparatus, no flaw was observed in the side wall surface when the polishing treatment was performed using the carriers of examples 9 and 10, and a flaw was observed in the side wall surface when the polishing treatment was performed using the carriers of comparative examples 5 and 6.

In addition, as a result of observing the 1 st reinforcing region and the 2 nd reinforcing region of the carrier of example 10 using a laser microscope, the 1 st glass fiber and the 2 nd glass fiber were also partially etched, respectively. Further, it was found that when the carrier of example 10 was used and the polishing treatment was performed under the above conditions, the number of defects on the side wall surface and the main surface was small, and adverse effects on the glass substrate could be avoided.

< grinding test >

Next, a magnetic disk glass substrate was produced based on embodiment 2, except that the carriers of examples 9 and 10 and comparative examples 5 and 6 were used, and a double-side grinding apparatus provided with a planetary gear mechanism was used to perform finish grinding. grains of grinding pad were stuck and fixed to a flat plate, and the load on the substrate was 150g/cm²The plate rotation speed was 25rpm, and the processing time was 60 minutes, 100 lots of experiments were performed by replacing the substrate without replacing the carrier (examples 11 and 12 and comparative examples 7 and 8, respectively), and after cleaning the glass substrates of the 1 st lot and the 100 th lot, scratches on the side wall surfaces were detected. In addition, since 100 sheets of glass were processed for each batch and 5 sheets of carriers capable of holding 20 sheets of glass were used for each batch, 10000 sheets of glass substrates were produced in total in each experimental example.

TABLE 4

In comparative examples 7 and 8, no flaw was observed on the side wall surface of the glass substrate in batch 1, but a flaw was observed in batch 100. Then, the inner wall surfaces of the holding holes of the carrier after processing of 100 batches were detected, and as a result, glass fibers protruding vertically were observed. That is, it is thought that only a portion composed of a resin material among portions including the inner wall of the holding hole is peeled off during grinding, glass fibers protruding perpendicularly are exposed, and a flaw occurs at the end face of the glass substrate. On the other hand, in examples 11 and 12, no flaw was observed on the side wall surface of the glass substrate in both the 1 st batch and the 100 th batch.

Evaluation of the main surface of the glass substrate by a laser microscope was not carried out because the roughness of the substrate surface was large and difficult to perform. In addition, since the machining load was large, the side wall surface scratches were more clearly observed in comparative examples 7 and 8 than in comparative examples 5 and 6.

The polishing carrier, the method for manufacturing the polishing carrier, and the method for manufacturing the magnetic disk substrate of the present invention have been described above in detail, but the present invention is not limited to the above embodiments, and various improvements and modifications can be made to the present invention within a scope not departing from the gist of the present invention.

(description of symbols)

1,30 vectors

3,32 holding holes

5,36 inner wall surface (inner wall surface)

5a 1 st inner wall surface

5b 2 nd inner wall surface

7 annular region

10 grinding pad

11 st 1 reinforcing region

13 nd 2 nd strengthening region

15 other part of the annular region

21 st glass fiber

23 nd 2 glass fiber

31 tooth part

33,34 glass fiber

35 orientation direction wall part

37 No. 1 curved surface

38 plane

39 nd 2 curved surface

40 upper flat plate

60 lower flat plate

61 Sun Gear

62 internal gear

71 supply tank

72 piping

Claims

1. A method for manufacturing a carrier for polishing or grinding treatment, the carrier having a holding hole for holding a disk-shaped substrate when the substrate is polished or ground by sandwiching the substrate between an upper plate and a lower plate,

the method for producing the carrier for polishing or grinding treatment is characterized by comprising:

an etching step of etching a part of an inner peripheral wall surface of a holding hole of a plate material which is made of a composite material including fibers oriented in at least one direction and a resin material and in which the holding hole is formed in a circular shape,

in the etching step, etching is performed so as to form an etched region and a non-etched region on the inner peripheral wall surface,

in the non-etched region, a normal direction of the inner peripheral wall surface does not coincide with an orientation direction of the fibers.

2. The method for producing a carrier for grinding or milling treatment according to claim 1,

the etched region includes a region on the inner peripheral wall surface where a normal direction of the inner peripheral wall surface coincides with an orientation direction of the fibers.

3. A method for manufacturing a carrier for polishing or grinding treatment, the carrier having a holding hole for holding a disk-shaped substrate when the substrate is polished or ground by sandwiching the substrate between an upper plate and a lower plate,

in the etching step, etching is performed on the inner peripheral wall surface so as to form etched regions of the fibers exposed on the inner peripheral wall surface and non-etched regions of the fibers exposed on the inner peripheral wall surface,

4. The method for producing a carrier for grinding or milling treatment according to claim 3,

the unetched region includes a region on the inner peripheral wall surface where a normal direction of the inner peripheral wall surface does not coincide with an orientation direction of the fibers.

5. The method for producing a carrier for grinding or milling treatment according to any one of claims 1 to 4, wherein the carrier is a single-layer carrier,

the plate material is obtained by impregnating a resin material with a glass cloth which is obtained by plain-weaving glass yarns oriented in 2 orthogonal directions, which are bundles of glass fibers,

the inner peripheral wall surface includes 4 etched regions formed in directions of 0 °, 90 °, 180 °, and 270 ° around the center of the holding hole.

6. The method for producing a carrier for grinding or milling treatment according to claim 5,

one of the glass fibers has a diameter of 5 to 10 μm,

the width of the glass yarn in the plate material along the plane direction of the plate material is 200 to 700 μm.

7. The method for producing a carrier for grinding or milling treatment according to claim 5,

in the etched region, glass yarns that are oriented in the normal direction on the inner peripheral wall surface among the glass yarns oriented in the 2 orthogonal directions are not present,

in the unetched regions, there are both the glass yarns oriented in the orthogonal 2 directions.

8. The method for producing a carrier for grinding or milling treatment according to any one of claims 1 to 4, 6 and 7, wherein the carrier is a single-layer carrier,

in the etching step, masking is performed in which a mask material is provided on the region not to be etched on the inner peripheral wall surface before the etching, and the mask material is removed after the etching.

9. The method for producing a carrier for grinding or milling treatment according to claim 8,

in the etching step, before the etching, the plurality of plate materials in which the holding holes are formed are arranged to overlap each other such that the orientation direction of the fibers and the positions of the holding holes overlap each other, and the inner peripheral wall surfaces of the holding holes of the overlapped plate materials are covered.

10. The method for producing a carrier for grinding or milling treatment according to any one of claims 1 to 4, 6, 7 and 9,

in the etching step, an etchant for etching the fiber is applied to the etched region, thereby performing the etching.

11. The method for producing a carrier for grinding or milling treatment according to claim 10,

in the etching step, before the application of the etchant, the plurality of plate materials in which the holding holes are formed are arranged in a stacked manner such that the orientation direction of the fibers and the positions of the holding holes overlap each other, and the etchant is applied to the inner peripheral wall surface of the holding hole of the stacked plate materials.

12. The method for producing a carrier for grinding or milling treatment according to any one of claims 1 to 4, 6, 7, 9 and 11,

the holding hole is formed by a holding hole forming step in which a circular holding hole is formed in a plate material composed of a composite material including fibers and a resin material oriented in at least one direction,

in the holding hole forming step, after the plurality of plate materials are overlapped in the orientation direction of the fibers before the holding hole is formed, the holding hole is formed so as to penetrate the plurality of plate materials.

13. A method for manufacturing a substrate, comprising a polishing or grinding process in which a main surface of the substrate is polished or ground while holding the substrate by the polishing or grinding carrier manufactured by the method for manufacturing a polishing or grinding carrier according to any one of claims 1 to 12.

14. A carrier for grinding or milling treatment, characterized in that,

the carrier for grinding or milling treatment has glass fibers oriented in 2 orthogonal directions and circular holding holes,

the inner peripheral wall surface of the holding hole includes 4 reinforcing regions formed in directions of 0 DEG, 90 DEG, 180 DEG, and 270 DEG around the center of the holding hole,

in the 4 reinforced regions, only glass fibers oriented in a direction different from the normal direction of the inner peripheral wall surface are present.

15. The carrier for grinding or milling treatment according to claim 14,

the reinforcing regions are formed on the inner peripheral wall surface at wall surface portions within a range of ± 20 ° with respect to directions of 0 °, 90 °, 180 °, and 270 ° around the center of the holding hole, respectively.

16. The carrier for grinding or milling treatment according to claim 14 or 15,

the length of the reinforcing region along the radial direction of the holding hole is 2 to 10 [ mu ] m.

17. A method for manufacturing a substrate, characterized by comprising: polishing or grinding the main surface of the substrate in a state where the substrate is held in the holding hole of the polishing or grinding treatment carrier according to any one of claims 14 to 16.

18. The method for manufacturing a substrate according to claim 13 or 17, wherein the substrate is a substrate for a magnetic disk.