CN112091811B

CN112091811B - Carrier and method for manufacturing substrate using the same

Info

Publication number: CN112091811B
Application number: CN202011023491.3A
Authority: CN
Inventors: J·珀姆查
Original assignee: Hoya Corp; Hoya Glass Disk Thailand Ltd
Current assignee: Hoya Corp; Hoya Glass Disk Thailand Ltd
Priority date: 2016-03-31
Filing date: 2017-03-31
Publication date: 2022-09-06
Anticipated expiration: 2037-03-31
Also published as: SG10202004819TA; JP2018022549A; JPWO2017171052A1; WO2017171052A1; JP6236191B1; JP7018292B2; SG11201802381PA; CN108349063A; MY174348A; CN112091811A; CN108349063B

Abstract

Provided are a carrier and a method for manufacturing a substrate using the same, which can obtain a high-quality substrate with a higher yield than before. A carrier (104) for polishing or grinding having a holding hole (122) for holding a substrate (for example, a glass substrate (102)), characterized in that a plurality of recesses (128) are provided in at least one surface of the carrier in a region (126) other than the peripheral edge (130) of the holding hole.

Description

Carrier and method for manufacturing substrate using the same

The present application is proposed in article 42 based on rules for patent law implementation, and is a divisional application of the invention patent application "carrier and method for manufacturing substrate using the carrier" having an application date of 2017, 31/3 and 201780003634.4 (international application number: PCT/JP 2017/013739).

Technical Field

The present invention relates to a carrier used for polishing a main surface of a plate-like substrate such as a substrate for a magnetic recording medium, a glass for a liquid crystal screen, or a silicon wafer, and a method for producing a substrate using the carrier.

Background

In recent years, information recording technology, particularly magnetic recording technology, has been remarkably advanced with the advancement of information technology. In a magnetic recording medium such as an HDD (hard disk drive) which is one of the magnetic recording media, a substrate made of glass or an aluminum alloy is used as a substrate.

The main surface of the substrate is polished simultaneously on the front surface and the back surface by, for example, a double-side polishing apparatus. In the double-side polishing apparatus, for example, a carrier holding substrate having a holding hole is sandwiched between an upper platen and a lower platen to which a polishing pad is attached. Then, the polishing liquid is supplied between the substrate and the polishing pad, and the substrate held by the carrier and the polishing pad are relatively moved by using a planetary gear mechanism or the like, whereby the entire main surface of the substrate is uniformly polished. This polishing method is a preferable method in terms of production efficiency because it can simultaneously polish a plurality of substrates.

In this polishing method, after polishing the surface of the substrate, the upper platen is raised, and the polished substrate is taken out from the carrier. However, when the upper platen is raised, the carrier adheres to the upper platen and is lifted up, and then falls off the upper platen and falls on the substrate, which causes a problem that the surface of the substrate is damaged.

In view of the above problem, in patent document 1 and patent document 2, the surface roughness of the front surface and the back surface of the carrier, and the contact angle of the front surface and the back surface are made different, thereby preventing the adhesion of the carrier to the upper platen.

Prior art documents

Patent document 1: japanese laid-open patent publication No. 2013-132744

Patent document 2: japanese laid-open patent publication No. 2013-132745

Disclosure of Invention

Problems to be solved by the invention

However, in the carrier described in the above document, it is not possible to sufficiently suppress the adhesion of the carrier to the upper platen. The carrier described in the above-mentioned document also has a problem of high production cost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a carrier capable of obtaining a high-quality substrate with a higher yield than ever before, and a method for manufacturing a substrate using the carrier.

Means for solving the problems

The inventors have intensively studied the cause of the above-described problems and then speculated as follows. That is, the main surface of the carrier and the surface of the polishing pad are both made of the same material such as "resin", and have high affinity. Further, since a relatively soft resin is used as the resin material on the surface of the polishing pad, the resin material easily follows the shape of the surface of the carrier and is easily attached to the surface of the carrier. Therefore, the roughness and undulation of the main surface of the carrier are slightly different between the front surface and the back surface, and the adsorption force of the main surface of the carrier to the surface of the polishing pad is not greatly different, and as a result, the adhesion of the carrier to the upper platen cannot be sufficiently suppressed.

In the above patent document, for example, the upper surface of the carrier is subjected to press working to form roughness, but in this case, the surface of the carrier is maintained in a state of being covered with resin. The present inventors have thus studied the material and shape of the front surface of the carrier, and have made extensive studies in consideration of the fact that the adsorption force between the front surface and the back surface of the carrier can be changed more than before.

That is, a typical structure of the carrier of the present invention is a carrier for polishing or grinding, which has a holding hole for holding a substrate, and is characterized in that a plurality of protrusions mainly composed of glass are present in at least a partial region of at least one surface of the carrier.

According to the above configuration, since the plurality of protrusions mainly composed of glass are present on the surface of the carrier, air is likely to enter between the upper surface of the carrier and the polishing pad on the upper platen side when the upper platen is raised, and adhesion can be prevented. In the present invention, since the polishing pad or the grinding pad attached to the platen surface is mainly composed of a resin-based component, the material of the polishing pad or the grinding pad is different from that of the polishing pad or the grinding pad. Therefore, the effect of preventing the adhesion (adsorption) of the carrier to the upper platen is high. In addition, since the protrusions are made of glass, the abrasion resistance (durability) of the protrusions is increased, and therefore, the same carrier is subjected to polishing treatment more times, and adhesion to the upper platen can also be prevented. That is, the polishing process can be performed a plurality of times using the same carrier, and the durability of the carrier can be improved.

In the above-described configuration, in other words, a carrier for polishing or grinding having a holding hole for holding a substrate is characterized in that a protrusion forming region is present on at least one surface of the carrier, and a plurality of protrusions mainly composed of glass are present in the protrusion forming region.

The height of the protrusion may be 2 μm or more. If the height of the protrusions is less than 2 μm, the effect of suppressing the adhesion of the carrier to the upper platen may not be exerted. Further, if the height of the protrusions is 3 μm or more, the suppression effect can be further improved, and therefore, it is more preferable. On the other hand, from the viewpoint of the above-mentioned suppression effect, the upper limit of the height of the protrusion is not particularly limited, but if the height of the protrusion exceeds 50 μm, there is a case where, when both surfaces of the substrate are processed, the difference between the front surface and the back surface is slightly increased in the surface shape of the substrate after processing. It is presumed that this phenomenon damages the surface of the polishing pad on the platen side facing the polishing pad if the height of the protrusions is too high. Therefore, the height of the protrusions is preferably 50 μm or less. From the above, the height of the protrusions is more preferably 2 to 50 μm.

The width of the protrusion may be 50 μm or more. By setting the width of the protrusion within this range, the wear resistance of the protrusion can be improved, and the effect of suppressing the adhesion of the carrier to the upper platen can be maintained for a long period of time. The width of the protrusion is set to the longest length in the direction parallel to the main surface of the carrier. On the other hand, from the viewpoint of the effect of suppressing the sticking, there is no upper limit to the width of the above-mentioned protrusions, but if it exceeds 600 μm, there is a case where, particularly when the protrusions are formed only on one side, the friction of the front surface and the back surface of the carrier varies, and abnormal noise is generated during the processing. If abnormal noise occurs, it is necessary to check the machining device, and the manufacturing efficiency is lowered, which is not preferable. Therefore, the width of the protrusion is more preferably 600 μm or less. From the above, it is further preferable that the width of the protrusion is 50 to 600 μm.

The projection as a whole may be in the shape of an upwardly convex circular arc. The upwardly convex arc shape means, in other words, a shape in which the cross-sectional area of the surface parallel to the main surface of the carrier becomes smaller as it becomes the upper portion, or a mountain shape as a whole, or the like. If this shape is used, the protrusion does not have a corner at the top of about 90 degrees, but rather has a circular shape. Therefore, the polishing pad is less likely to be damaged, and as a result, both surfaces of the glass substrate can be polished to the same quality even in carriers having different specifications for the front and back surfaces.

The carrier may be made of a material in which glass fibers are woven and impregnated with a resin. At this time, the plurality of protrusions present in the carrier may include fibrous glass. Further, the plurality of protrusions present in the carrier may be formed substantially regularly in the grid of glass fibers. In addition, the plurality of protrusions present in the carrier may be formed of raised glass fibers in a lattice of glass fibers, or may be formed by a part of glass fibers standing up. Further, 1 glass fiber may be obtained by bundling relatively thin glass fibers.

Thus, in the case of using a sheet material in which glass fibers are woven and impregnated with a resin as a carrier, the glass fibers are generally woven in a bundle state and pressed and formed into a sheet shape in a state in which the glass fibers are impregnated with a resin. That is, the bundle of glass fibers is fixed by the resin in a state of being pressed in the thickness direction of the sheet. Thus, there is a case where when the resin in the periphery of the glass fiber is removed, the stress is released, and the glass fiber is raised to form a protrusion. In addition, if a part of the glass fiber is cut at this time, a protrusion may be formed in a state where a part of the glass fiber stands up. This enables formation of a protrusion mainly composed of glass.

Preferably, the protrusion is formed to avoid the periphery of the holding hole by a predetermined width. If the protrusion is formed to the contour of the holding hole, damage may occur on the inner wall surface of the holding hole or the shape of the holding hole may be changed. In this case, free movement of the substrate during the polishing process is inhibited, uniform polishing of the main surface of the substrate is inhibited, or damage is generated on the end face of the substrate. From the viewpoint of work efficiency, the predetermined width is preferably 1mm or more, and more preferably 2mm or more.

The protrusions may be formed in a plurality of regions separated from each other. In other words, the region where the protrusions are present on the surface of the carrier may be present as a plurality of regions separated from each other. Thus, when a plurality of holding holes are provided to improve the manufacturing efficiency and the space between the 2 holding holes is very narrow, the area where the protrusion exists is provided while avoiding the space between the 2 holding holes, and therefore, the work efficiency of forming the protrusion can be improved.

Further, a plurality of regions may be formed as recesses having a predetermined depth on the surface of the carrier, and the projections may be formed in the recesses. This reduces the possibility of contact between the protrusions and the polishing pad, improves the durability of the protrusions, suppresses generation of dust due to friction with the polishing pad, and improves the quality of the processed substrate surface. The depth of the recess is, for example, 0.3 to 30 μm. Preferably, the total area of the regions where the recesses are formed on one surface of the carrier is 5 to 80% of the total area.

In order to solve the above-described problems, a typical structure of a method for manufacturing a substrate using the carrier according to the present invention is characterized by having a polishing process of holding a substrate in a holding hole of the carrier for polishing, and simultaneously polishing both surfaces of the substrate by sandwiching the substrate between upper and lower platens having polishing pads or grinding pads. In this case, the polishing carrier is provided in the polishing apparatus with the surface having the protrusions as an upper side.

In the polishing process of the present invention, the face having the protrusions in the carrier is opposed to, for example, a polishing pad or a grinding pad on the upper platen side. Further, the carrier is substantially thinner than the substrate, and the difference in thickness between the carrier and the substrate is small, and the carrier repeatedly comes into contact with and separates from the substrate during the processing. The main component of the protrusions is glass, and the polishing pad or the grinding pad is mainly composed of a resin-based component, and therefore, the materials of the polishing pad and the grinding pad are greatly different. Therefore, the effect of preventing the carrier from adhering (adsorbing) to the upper platen is high. Therefore, when the upper platen is lifted after the polishing process, the following situation does not occur: the carrier adheres to the upper platen and lifts up, and then falls off from the upper platen and falls on the substrate, damaging the substrate surface of the substrate.

In addition, the grinding pad refers to a fixed abrasive tool including diamond abrasive grains, for example. For example, the fixed abrasive tool is shaped to fix diamond abrasive grains with resin or metal. Further, 1 diamond abrasive particle may be replaced with an aggregate abrasive particle in which a plurality of diamond abrasive particles are combined into 1 by vitreous (vitreous), metal, resin, or the like. The substrate is processed by exposing the diamond abrasive grains or the aggregate abrasive grains to the surface of the fixed abrasive tool. In the present invention, the average particle diameter (hereinafter, simply referred to as "average particle diameter") of the diamond abrasive grains contained in the fixed abrasive grain tool is preferably 0.1 to 10 μm.

Another typical configuration of the carrier of the present invention is a carrier for polishing or grinding, which has a holding hole for holding a substrate, and is characterized in that a plurality of recesses are provided in at least one surface of the carrier in a region other than the peripheral edge of the holding hole.

According to the above configuration, since the plurality of concave portions are provided on the surface of the carrier, the polishing liquid supplied to the carrier from above can be accumulated in the concave portions when the surface of the substrate is polished. Therefore, even when the polishing pad and the carrier are brought into close contact with each other, the close contact area of the resin on the surfaces of the polishing pad and the carrier is reduced, so that the adsorption force of the front surface and the back surface of the carrier to the polishing pad is reduced, and the effect of preventing the adhesion (adsorption) is high.

At least 1 of the plurality of recesses may be formed such that a contour of the recess does not contact the gear portion of the carrier. This enables the polishing liquid to be reliably deposited in the recessed portion when polishing the substrate surface, and therefore, the effect of preventing sticking is high.

The depth of the recess may be 0.3 to 30 μm. By setting the depth of the recess to 0.3 μm or more, the polishing liquid can be sufficiently stored in the recess, and the adhesion of the carrier can be prevented. On the other hand, if the depth of the recess exceeds 30 μm, the carrier warps during the polishing process, and the substrate to be polished may be detached from the carrier, thereby decreasing productivity. Therefore, the depth of the concave portion is more preferably 0.3 μm or more and 30 μm or less.

The contour forming the recess may be constituted by a free curve. The free curve may be a curve, for example. Designed as a free curve, thereby increasing surface tension. This enhances the effect of accumulating the polishing liquid, and therefore, the effect of preventing the adhesion is high.

The area occupied by the whole of the plurality of concave portions may be 5% or more of the area of the whole of at least one surface of the carrier. Here, when the ratio of the total area of the concave portions is less than 5%, the effect of preventing the sticking may not be sufficiently obtained because the polishing agent or the like adheres to the surface of the carrier in some cases. On the other hand, the upper limit of the ratio of the total area of the concave portions is not particularly limited. However, if the ratio is too large, the carrier warps and the substrate to be polished may be detached from the carrier, so the upper limit of the ratio is preferably 80% or less.

Further, it is preferable that the area of each of the plurality of concave portions is 1cm ² The above. When the area is less than 1cm ² In the case of the method, the effect of preventing adhesion cannot be sufficiently obtained. Further, it is more preferable that the area of the concave portion is 2cm ² The above. On the other hand, from the viewpoint of the effect of preventing sticking, the upper limit of the area is not particularly specified. However, if the area is too large, the carrier warps and the substrate to be polished may be detached from the carrier, and therefore 400cm is preferable ² The following. When a plurality of recesses are provided, the total thickness is preferably not less than 1/2 cm and is preferably 1cm ² The above. Preferably 1cm ² The number of the above recesses is not less than 2/3, and more preferably all. When 1cm ² When the number of the above-mentioned recesses is smaller than 1/2, which is the number of the entire regions, the number of the smaller recesses may increase, and therefore, the operation of forming the recesses by using a mask or the like becomes difficult, and the productivity of the carrier may deteriorate.

Preferably, the plurality of concave portions are formed to avoid the periphery of the holding hole by a predetermined width. If the recess is formed to the contour of the holding hole, there is a case where damage occurs to the inner wall surface of the holding hole or the shape of the holding hole is changed. In this case, free movement of the substrate during the polishing process is inhibited, uniform polishing of the main surface of the substrate is inhibited, or damage is generated on the end face of the substrate. The predetermined width is, for example, preferably 1mm or more, and more preferably 2mm or more, from the viewpoint of work efficiency.

Preferably, the plurality of recessed portions include a region surrounded by at least 3 or more holding holes. If the recessed portion is provided between 2 holding holes, the strength of the entire carrier may be reduced, and the number of times the carrier can be used may be reduced.

The carrier may be made of a material in which glass fibers are woven and impregnated with a resin. By applying a chemical method or a mechanical method to a carrier made of such a material, a plurality of concave portions can be provided on the surface of the carrier.

In order to solve the above problems, another typical configuration of the method for manufacturing a substrate using the carrier according to the present invention includes the following polishing process: a substrate is held in the holding hole of the polishing carrier, and both surfaces of the substrate are simultaneously polished by holding the substrate between upper and lower platens having polishing pads or grinding pads. In this case, the polishing carrier is provided in the polishing apparatus with the surface having the concave portion as an upper side.

Thus, in the polishing process of the present invention, the face having the concave portion in the carrier is brought into contact with the polishing pad or the grinding pad of the upper platen. Therefore, even when the carrier and the polishing pad are brought into close contact with each other, the close contact area of the resins on the surfaces of the carrier and the polishing pad can be reduced. Therefore, the adsorption force of the front and back surfaces of the carrier to the polishing pad is reduced, and the effect of preventing adhesion (adsorption) is high. Therefore, when the upper platen is raised after the polishing process, the following does not occur: the carrier is adhered to the upper platen and lifted up, and then falls down from the upper platen and falls on the substrate, damaging the substrate surface of the substrate.

Effects of the invention

According to the present invention, it is possible to provide a carrier capable of obtaining a high-quality substrate with a yield higher than that of the conventional carrier, and a method for manufacturing a substrate using the carrier.

Drawings

Fig. 1 is a cross-sectional view showing a main part of a double-side polishing apparatus used for polishing a substrate surface according to the present embodiment.

Fig. 2 is a schematic view showing a part of the upper surface of the carrier of fig. 1 in an enlarged manner.

Fig. 3 is a diagram showing an example of manufacturing the carrier of the present embodiment.

Fig. 4 is a schematic view of the upper surface of the carrier before forming the protrusions.

Fig. 5 is a schematic view of the upper surface of the carrier after forming the protrusions.

Fig. 6 is a plan view showing the carrier of fig. 1.

Fig. 7 is a schematic view showing a recess provided on the upper surface of the carrier of fig. 6 and its surroundings.

Fig. 8 is a schematic diagram showing an enlarged B region of fig. 7 (a).

Description of the reference symbols

100 … double-sided lapping apparatus, 102 … glass substrate, 104 … carrier, 106 … carrier mounting section, 108 … upper platen, 110 … lower platen, 112 … internal gear, 114 … sun gear, 115 … gear section, 116, 118, 146 … lapping pad, 120 … supply tube, 122a, 122b, 122c … holding hole, upper surface of 124 … carrier, 126 … area, 128 … recess, peripheral edge of 130 … holding hole, entire periphery of 132 … recess, main surface of 134 … carrier, lower surface of 135 … carrier, 136 … projection, 138 … etchant, 142 … lapping machine, front end of 144 … lapping machine, 150 … glass fiber, 152 … mesh, 154 … raised portion

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, other specific numerical values and the like shown in the embodiments are merely illustrations for easy understanding of the invention, and are not intended to limit the invention unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are given the same reference numerals, and overlapping description is omitted, and elements not directly related to the present invention are omitted from illustration.

[ embodiment 1]

Fig. 1 is a cross-sectional view showing a main part of a double-side polishing apparatus used for polishing a substrate surface according to the present embodiment. In the present embodiment, only the double-side polishing apparatus will be described, but the present invention is not limited thereto, and for example, a polishing pad provided on a platen may be changed to a polishing pad, and a double-side polishing apparatus having the same function and the like may be used.

As the substrate (object to be processed), for example, a circular or square plate-like substrate can be used. Specific examples of these substrates include a magnetic disk substrate such as a substrate made of glass or aluminum alloy, an aluminum alloy substrate having a plating film of NiP alloy formed on the surface thereof, a rectangular glass substrate such as a liquid crystal panel, a glass cover for screen protection, a photomask substrate, a silicon wafer, and the like, but the material, shape, size, and the like of the substrate are not limited thereto. The present invention is particularly suitable for use in processing a substrate for a magnetic disk, since both surfaces of the substrate need to have low roughness and low defects, and a large number of substrates can be processed at a time with high quality. Next, a case where a magnetic disk glass substrate is used as a workpiece will be described as an example.

The double-side polishing apparatus 100 is an apparatus for polishing the upper and lower surfaces of a glass substrate 102, and includes a carrier mounting portion 106 on which a carrier 104 is mounted, and an upper platen 108 and a lower platen 110. The carrier mounting portion 106 has an internal gear 112 and a sun gear 114 that are rotationally driven at predetermined rotational ratios, respectively, and mounts the carrier 104.

The carrier 104 has a gear portion 115 formed on an outer periphery thereof, and is attached to the carrier attachment portion 106 so that the gear portion 115 is engaged with the internal gear 112 and the sun gear 114. The carrier 104 performs planetary gear motion while being attached to the carrier attachment portion 106, and revolves around the sun gear 114 while rotating.

The upper platen 108 and the lower platen 110 are driven to be inverted with respect to each other across the carrier mounting portion 106. Polishing

pads

116 and 118 are attached to the surfaces of the upper platen 108 and the lower platen 110 facing the glass substrate 102, respectively. The upper platen 108 is movable in the vertical direction, and presses the

polishing pads

116 and 118 on the upper and lower sides of the glass substrate 102. Foams of synthetic resins such as polyurethane and polyester are used as the

polishing pads

116 and 118.

Then, slurry (polishing liquid) containing abrasive grains is supplied from above the carrier 104 through a supply pipe 120 provided on the upper platen 108. Thus, in the double-side polishing apparatus 100, the carrier 104 performs the planetary gear motion while the polishing liquid is supplied, and the upper platen 108 and the lower platen 110 are reversed with respect to each other. Therefore, in the double-side polishing apparatus 100, the glass substrate 102 and the

polishing pads

116 and 118 are moved relatively, and the upper and lower main surfaces of the glass substrate 102 are polished.

The carrier 104 has more than 1 retention hole 122. The carrier 104 holds 1 or more glass substrates 102, which are sandwiched between the polishing pad 116 of the upper platen 108 and the polishing pad 118 of the lower platen 110 and polished, by holding holes 122. In the double-side polishing apparatus 100, after polishing the upper and lower main surfaces of the glass substrate 102, the upper platen 108 is raised, and the polished glass substrate 102 is taken out from the carrier 104.

The carrier 104 is used for polishing, but is not limited to this, and can be widely used for main surface grinding other than polishing, such as friction using free abrasive grains or grinding using a grinding pad with fixed abrasive grains. The carrier 104 may be a carrier in which the carrier body portion having the holding hole 122 and the gear portion 115 are separate members and the carrier body portion and the gear portion are used in combination.

Fig. 2 is a schematic diagram showing a part of the upper surface of the carrier 104 of fig. 1 in an enlarged manner. Fig. 2 (a) is a plan view showing a part of the upper surface 124 of the carrier 104 in an enlarged manner. Fig. 2(b) is a sectional view taken along line a-a of fig. 2 (a).

As shown in fig. 2 (a), a plurality of protrusions 136 are present on the upper surface 124 of the carrier 104. The main component of the plurality of protrusions 136 is glass. The surface other than the protrusions is, for example, resin. Examples of the resin include epoxy resins, polyvinyl chloride, polycarbonate, phenol, polyacetal copolymers, and polyethylene terephthalate. Among them, particularly, the epoxy resin, if impregnated in the glass fiber, can improve the flexural strength and the elastic modulus, and is particularly preferable because the water resistance and the chemical resistance are high.

The carrier 104 is made of a material in which glass fibers are woven and impregnated with a resin, which will be described in detail later, but may be made of fibrous glass or may be arranged substantially regularly, for example, in an approximately lattice shape. In fig. 2(b), the protrusions 136 are formed only on the upper surface 124 of the carrier 104 and are not provided on the lower surface 135, but may be provided on both the upper and lower surfaces as long as the effect of suppressing the suction to the upper platen 108 side is not impaired. When the protrusions 136 are provided on both the upper and lower surfaces, the height and number of the protrusions 136, the area where the protrusions 136 are formed (protrusion forming area), and the like may be appropriately adjusted in each surface.

For the protrusion 136 shown in fig. 2(b), it is preferable that the height La is 2 to 50 μm and the width Lb is 50 to 600 μm, respectively. The width dimension Lb is the longest length in the direction of the main surface 134 of the carrier 104.

The protrusion 136 has an arc shape protruding upward, and in fig. 2(b), has a mountain shape. However, the shape is not limited to this as long as it is an arc shape that protrudes upward as a whole, and may be a shape whose area becomes smaller toward the upper portion, in other words, a shape whose sectional area based on a plane parallel to the main surface 134 of the carrier 104 becomes smaller toward the upper portion. In addition, for example, an oval shape or an upwardly convex hemispherical shape is also possible. In this shape, the protrusion 136 does not have a corner of about 90 degrees at the top 136A, and is rounded.

In the case where the carrier 104 is made of a material in which glass fibers are woven and impregnated with a resin, the projections 136 may be formed by raising the glass fibers in a lattice of the glass fibers or the projections 136 may be formed by cutting a part of the glass fibers in an upright state by performing the method for manufacturing the carrier 104 according to the present embodiment described later. That is, a plurality of glass material protrusions 136 may be formed substantially regularly on the upper surface 124 of the carrier 104. The glass protrusions 136 have higher abrasion resistance than the resin protrusions, and are less likely to be abraded even if the polishing process is repeated.

In other words, the protrusions 136 of the glass material may be formed by exposing a part of the glass fibers contained in the carrier on the outermost surface or on the outer surface. Additionally, the exposed or exposed glass fibers may comprise chopped glass fibers.

The above-described protrusions 136 need not necessarily be formed on the entire surface of the main surface of the carrier. Since the protrusion 136 mainly composed of glass of the present invention has a very high effect of preventing adhesion, sufficient effects can be obtained by forming the protrusion 136 on at least a part of the main surface. In the present specification, a region where the protrusion 136 is formed is also referred to as a "protrusion forming region". When the above-described protrusion forming region is provided in a part of the main surface of the carrier, the protrusion forming region may be formed by being divided into a plurality of regions.

Preferably, the area occupied by the projection forming region (when a plurality of projection forming regions are present, the total area thereof) is 10% or more of the area of the entire at least one surface of one of the carriers in which the projection forming region is present. When the area ratio occupied by the protrusion-forming region is less than 10%, there is a case where the effect of preventing adhesion in the final stage of long-term continuous processing is reduced due to adhesion of the abrasive or the like to the surface of the carrier. More preferably, the ratio of the area is 20% or more. In addition, when the ratio of the area is small, the effect of preventing the adhesion can be improved even with a small area by forming the protrusion around the outer periphery of the carrier.

Further, it is preferable that the protrusion forming regions each have an area of 1cm ² The above. When the area is less than 1cm ² In the case, the effect of preventing the adhesion may not be sufficiently obtained. Further, it is more preferable that the respective areas of the protrusion forming regions are 2cm ² As described above. On the other hand, from the viewpoint of the effect of preventing sticking, the upper limit of the area is not particularly specified. However, if the area is too large, a mask or the like for avoiding the holding hole is requiredIn operation, the productivity of the carrier may be deteriorated, and therefore, 400cm is more preferable ² The following. In addition, when there are a plurality of protrusion-forming regions, 1/2, which is less than the whole, may be less than 1cm ² . Further preferably less than 1cm ² The number of protrusion-forming regions of (a) is less than 1/3, and still more preferably 1 is none. When less than 1cm ² When the number of the protrusion forming regions of (2) is not less than 1/2, the protrusion forming operation by a mask or the like may be difficult, and the productivity of the carrier may be deteriorated.

In addition, in the above-mentioned protrusion forming region, it is preferable to be 1mm per unit ² There is a density of 0.5 or more to form the protrusions. By setting the number to be more than 0.5, the effect of suppressing the adhesion of the carrier to the platen can be reliably obtained. Further preferably every 1mm ² More than 1 protrusion is formed. On the other hand, although there is no particular upper limit to the density from the viewpoint of the effect of suppressing the above-mentioned sticking, it is more preferable to set the density at every 1mm from the viewpoint of damage to a polishing pad or a grinding pad (in the present specification, these are collectively referred to as "processing pad") provided on the platen surface ² Less than 10 protrusions are formed. If damage to these processing pads occurs, when substrate manufacturing based on long-term continuous processing is performed, the difference between the surface and the back surface may become large at the final stage of manufacturing. The density of the protrusions may be obtained by observing a plurality of protrusion formation regions with a scanning electron microscope (hereinafter abbreviated as SEM) and averaging the results.

For example, the carrier 104 of the present invention can be manufactured by the following method. For example, in the case of a carrier made of a material in which glass fibers are woven and impregnated with a resin, the resin or glass, which is a constituent material of the carrier, may be removed by a chemical or mechanical method (see fig. 3) to expose a part of the glass fibers located in a position close to the surface of the carrier. Even in the case of using any method, the protrusions 136 can be formed on any region of the surface of the carrier 104 by appropriately combining with a masking process when the carrier 104 is manufactured.

As the chemical method, for example, a method such as dissolution or etching can be used. In these methods, it is only necessary to appropriately select a substance capable of dissolving or etching and bring a resin or glass into contact therewith. In addition, a substance that can dissolve or etch both the resin and the glass may be used.

Fig. 3 (a) is a diagram showing an example of manufacturing the carrier 104 of the present embodiment using a chemical method. Here, an etchant 138 for dissolving the resin is applied to the region 126 (protrusion forming region) indicated by oblique lines in the drawing on the upper surface 124 of the carrier 104. As the etchant 138, a liquid or paste etchant may be appropriately selected.

The region 126 may be the entire upper surface 124 of the carrier 104 or a part thereof as long as the protrusion 136 can be formed. In fig. 3, as the region 126, a region is illustrated which is located at a position other than the peripheral edge 130 of the 3

holding holes

122a, 122b, and 122c of the upper surface 124 of the carrier 104 and is surrounded by these holding

holes

122a, 122b, and 122 c. In addition, when the carrier 104 is manufactured, the above-described chemical method or mechanical method can be performed only on a part of the surface of the carrier 104 by appropriately masking.

When the protrusion 136 is formed on a part of the surface of the carrier 104, as described above, it is preferably formed in the region 126 surrounded by at least 3 or

more holding holes

122a, 122b, 122 c. Assuming that the area where the protrusion 136 is formed is provided between 2 holding holes, there are cases where the manufacturing cost and time of the carrier 104 increase.

Further, the protrusion 136 is preferably formed at a position other than the peripheral edge 130, for example, so as to avoid the periphery of the holding hole 122 by a predetermined width. Assuming that the protrusion 136 is formed to the contour of the holding hole 122, there are cases where damage occurs to the inner wall surface of the holding hole 122 or the shape of the holding hole 122 is changed. In this case, free movement of the substrate during the polishing process may be inhibited, uniform polishing of the main surface of the substrate may be inhibited, or damage may occur to the end surface of the substrate. The predetermined width is preferably 1mm or more, and more preferably 2mm or more, for example, from the viewpoint of work efficiency.

It is preferable that the region 126 provided with the protrusion 136 be a plurality of regions separated from each other. Thus, when a plurality of holding holes 122 are provided to improve the manufacturing efficiency and the space between the 2 holding holes 122 is very narrow, the area where the protrusion 136 exists can be avoided between the 2 holding holes 122, and therefore the manufacturing efficiency of the carrier 104 can be improved.

Further, a plurality of concave regions having a predetermined depth may be formed on the surface of the carrier 104, and the protrusions 136 may be formed in the concave regions. This reduces the possibility of contact between the protrusions 136 and the polishing pad, improves the durability of the protrusions 136, suppresses generation of dust due to friction with the polishing pad, and improves the quality of the processed substrate surface. In addition, for example, the depth of the concave portion may be 0.3 to 30 μm. In addition, in one surface of the carrier 104, the total area of the regions where the recesses are formed is preferably 5 to 80% of the area of the entire surface of the carrier 104.

Further, as shown in fig. 3 (b), a mechanical method of rubbing or grinding the surface of the carrier 104 using an abrasive tool (grinding tool) such as sandpaper, rasp, grinder, or the like may be used. Here, a grinding tool 146 is attached to the front end 144 of the grinder 142 so as to be appropriately brought into contact with or the like, thereby grinding the surface of the region 126.

In the case of the carrier 104 made of a material in which glass fibers are woven and impregnated with a resin, since the hardness and physical properties of glass and resin are greatly different from each other, the etching agent 138, the polishing tool, and the like are appropriately selected, and thus the removal target is one or both of the resin and the glass fibers.

Further, the above chemical method and mechanical method may be combined. For example, a surface with less burrs can be finished by substantially removing the resin by a mechanical method and then removing the resin by a chemical method. Further, if a large amount of burrs remain on the surface of the carrier, the polishing pad of the double-side polishing apparatus 100 may be damaged, or the burrs may be detached during the processing, which may cause contamination of the substrate surface with foreign matter.

In addition to the above method, a film of resin or metal may be laminated in a state where the region 126 of the carrier surface where the recess 128 is to be formed is masked, and then the mask may be removed to form the recess 128.

Next, a process of forming the protrusion 136 by applying the above-described chemical method or mechanical method to the region 126 of the upper surface 124 of the carrier 104 will be described with respect to a case where the carrier 104 is made of a material in which glass fibers are woven and impregnated with resin. Fig. 4 is a schematic view of the upper surface 124 of the carrier 104 prior to forming the protrusions 136. Fig. 5 is a schematic view of the upper surface 124 of the carrier 104 after forming the protrusions 136. In addition, in fig. 4 and 5, an enlarged view of a part of the region 126 is schematically illustrated.

The carrier 104 shown in fig. 4 is an enlarged view illustrating the surface of a sheet (sheet) material in which glass fibers 150 are woven and impregnated with resin. The sheet is a laminate of a woven fabric (each sheet impregnated with resin is referred to as a prepreg herein) in which bundles of several tens to several hundreds of glass fibers 150 are collected and alternately woven. The plain weave is a so-called plain weave in which the longitudinal bundles and the transverse bundles of the glass fibers 150 are alternately exposed on the surface side for each mesh 152. Since the thickness of the prepreg is, for example, 0.1 to 0.2mm and is very thin, the sheet is generally formed by laminating a plurality of prepregs and pressure-bonding the plurality of prepregs. Further, although not particularly shown in the drawings, the surface is covered with a resin layer.

In such a carrier 104, the glass fibers 150 have a mountain shape in a convex state on the surface layer side at the overlapping position of the mesh 152. For example, the vertical bundles or horizontal bundles of the glass fibers 150 rise substantially regularly on the surface side so as to undulate every 1 mesh 152. The glass fibers 150 are usually embedded in a resin and thus have a nearly flat shape in appearance, but when the resin on the surface is not present by dissolution or the like, the glass fiber bundles (or glass fibers) emerge in a mountain shape. This is because the prepreg is pressed with a strong force when it is pressure-bonded, and the prepreg is cured by the resin in this state. That is, a stress to return to the original thickness is generated in the glass fiber bundle. With this structure, the projections can be easily formed substantially regularly by relieving the stress applied to the glass fiber.

Fig. 5 (a) is a diagram schematically showing a state where the projections 136 are substantially regularly formed. Protrusions 136 as raised portions 154 where glass fiber bundles (or glass fibers) emerge and rise in a mountain shape are formed in each mesh 152 of the longitudinal bundles appearing on the surface side, and further in 1 mesh of the lateral bundles appearing on the surface side. Since the vertical glass fibers and the horizontal glass fibers are not necessarily woven uniformly microscopically, the thickness of the resin covering the surface may vary depending on the individual difference of the sheet or the position within 1 sheet. Fig. 5 (a) is an example in this case.

Therefore, for example, in fig. 5 (a), the protrusions 136 may be formed in all of the 9 cells 152 that can be confirmed, and the protrusions 136 may be formed only in 5 cells out of the cells 152 of the vertical glass fibers. However, in any case, since the protrusions 136 are formed in substantially the center of the mesh 152, the protrusions 136 can be formed substantially regularly. In other words, the protrusions 136 can be formed substantially regularly in accordance with the mesh 152. Further, if the protrusions are formed so as to cross the boundaries of the mesh 152, the area of the resin covering the surface may decrease, and the strength of the carrier 104 may decrease, so it is preferable to form the protrusions 136 so as not to cross the boundaries of the mesh 152. In other words, it is preferred that resin is present in the carrier surface between the protrusions.

In addition, when forming the protrusion 136, it is not necessary to remove the resin until the glass fiber 150 embedded in the resin is completely exposed. In the case of the carrier 104 made of a material in which the glass fibers 150 are woven and impregnated with resin, the glass fibers 150 (or glass fiber bundles) are fixed with resin in a state of being pressed in the thickness direction in the manufacturing process thereof. Therefore, by removing a part of the resin to such an extent that the stress applied to the glass fiber 150 is released, the protrusion 136 mainly composed of glass can be formed. The same applies to the case where the glass fiber embedded in the resin is a non-fibrous glass such as glass particles. That is, the resin does not necessarily need to be removed until the glass embedded in the resin is completely exposed.

When the protrusion is formed in this manner, the resin may remain on a part of the surface of the protrusion, but the glass component may be exposed on at least a part of the surface. Whether or not the glass component is exposed on the surface of the protrusion can be confirmed by SEM and energy dispersive X-ray analysis (hereinafter abbreviated as EDX), for example.

When the resin covering the glass fibers 150 is relatively thin on the surface of the carrier 104, a material capable of dissolving and etching glass can be used. In this case, the glass-dissolved substance permeates into the resin layer and reaches the glass fibers 150 inside, and a part of the dissolved substance of the glass fibers 150 is deposited on the surface against the coating film of the resin. As a result, the resin coating is broken, and a bulge including the glass fiber 150 is formed.

As illustrated in fig. 5 (b), a part of the glass fiber 150 constituting the protrusion 136 may be cut. If a portion of the glass fiber 150 is cut, a fragment of the glass fiber 150 easily protrudes from the surface. In other words, the cut glass fibers 150 tend to stand up with respect to the surface of the carrier 104. This allows the cut glass fiber to be included in a part of the protrusion 136, thereby improving the adhesion effect. Further, according to the study of the inventors, only a part of the glass fiber is cut under the etching conditions using the general etching solution for glass, and therefore the rigidity of the glass fiber is low and the polishing pad or the grinding pad facing thereto is not easily damaged. The reason for this is presumed to be that several hundred glass fibers are bundled, and a resin is present between each glass fiber.

In addition to the above method, when a resin is used as a component of the surface of the carrier, the protrusions may be formed by a method of scattering fine particles mainly composed of glass having a predetermined particle diameter on the surface of the carrier, pressing the fine particles while heating the fine particles, thereby embedding a part of the glass fine particles in the surface of the carrier, a method of applying an adhesive to the surface of the carrier, and then scattering the glass fine particles, or the like.

After the protrusion 136 mainly composed of glass is formed by the above method, a cleaning process and a burr removing process may be appropriately performed. Further, the height of the projection may be adjusted by using a dresser such as a diamond dresser, or a process for removing burrs may be performed.

Further, for example, a surface shape measuring device such as a stylus or an optical system may be used as appropriate to confirm the height, length, and other shapes of the protrusions 136 of the completed carrier 104. Further, by performing SEM observation and EDX-based elemental analysis on the protrusions 136, for example, it is possible to confirm whether or not the glass component is contained in the protrusions 136, whether or not the glass fiber is contained, and whether or not the cut glass fiber is present. Further, a micrometer or a length gauge may be used to confirm the removal depth of the resin and the variation in the thickness of the carrier 104.

According to the carrier 104 of the present embodiment, since the plurality of protrusions 136 are present on the upper surface 124 of the carrier 104, air easily enters between the upper surface 124 of the carrier 104 and the polishing pad 116 on the upper side when the upper platen 108 is raised. Therefore, the carrier 104 can be prevented from adhering to the upper platen 108. Further, since the protrusion 136 is made of a glass material, it has high abrasion resistance, and can prevent adhesion to the upper platen 108 more times.

Further, by regularly providing the protrusions 136, the ease of entry of air between the upper surface 124 of the carrier 104 and the upper polishing pad 116 is equalized, and adhesion can be more effectively prevented.

Further, the projection 136 as a whole can be formed in a smooth convex shape. Further, it may be possible that the top 136A thereof does not have an angle of about 90 degrees. Further, since the polishing pad 116 is circular as a whole, the polishing pad 116 in contact with the protrusions 136 is not easily damaged. As a result, both surfaces of the glass substrate 102 can be polished equally even in a carrier having a front surface and a back surface with different specifications.

As is clear from the examples described below, the protrusions 136 have a height La of 2 μm or more as shown in fig. 2b (see table 1), and therefore have high abrasion resistance and can prevent adhesion more effectively. For example, in the case of a sheet material in which glass fibers are woven and impregnated with resin, the height and width of the protrusions 136 can be adjusted by appropriately setting the thickness and number of bundles of the glass fibers 150, the weave, and the size (interval) of the mesh, in addition to changing the etching amount.

For example, in the case of a sheet formed by weaving glass fibers and impregnating the glass fibers with resin, the height and width of the protrusions 136 can be adjusted by appropriately setting the thickness of the glass fibers 150, the number of bundles, the weaving method, and the size (interval) of the mesh, in addition to changing the etching amount. For example, the height and width of the protrusion can be increased by increasing the etching amount of the resin.

The height and width dimension values of the protrusions 136 may be averaged to obtain the first 50 values having larger values when the random sampling measurement is performed on 100 protrusions. By doing so, the size of the protrusion that contributes to reliably preventing adhesion to the upper platen can be determined.

[ examples ]

Hereinafter, examples of the present invention will be described by way of example, but the present invention is not limited to only the following examples.

(preparation of substrate to be processed)

A target substrate was a glass substrate for a magnetic disk having a nominal 2.5 size (diameter of about 65mm), and a substrate obtained after completion of the first polishing treatment with a polishing liquid containing cerium oxide abrasive grains was prepared by a known method.

(preparation of Experimental support)

The carrier is produced by using a sheet in which glass fibers are woven and epoxy resin is impregnated, and shaping the sheet. Then, by appropriately using the above method, additional processing was performed on 1 surface of the carrier to form a plurality of protrusions having the specifications shown in table 1. In other specifications, the width of the protrusions was set to 300 μm, and the density of the protrusions was set to 3 (pieces/mm) ² ) The ratio of the area occupied by the protrusion-forming region on the main surface of the carrier was set to 50%. Further, as a result of confirmation by SEM, no cutting of the glass fiber was found. Here, for the dimension values of the height and width of the protrusions, 100 protrusions were sampled and measured at random, and the values were largeAverage of the first 50 values of (a).

(Experimental conditions)

The second polishing is performed on the substrate to be processed by the above-described or known method except for the following. As the polishing machine, both surfaces of the substrate to be processed are simultaneously polished using the above-described double-side polishing apparatus in which polishing pads are adhered to upper and lower platens, respectively. The polishing pad is a polyurethane resin polishing pad, and is a suede-type polishing pad having a surface layer with a fluff layer formed with a plurality of fine elongated pores (fluff) formed in the thickness direction by a foaming agent. The polishing agent was a polishing liquid containing colloidal silica particles having an average particle diameter (D50) of 30nm as polishing abrasive grains. The orientation of the carrier is set in the grinder so that the surface having the protrusions faces upward.

In the polishing process 1 time (1 batch), 5 carriers were provided so as to hold 10 substrates per 1 carrier, and both main surfaces of 50 substrates were polished at one time. The substrate to be processed was replaced, and 20 batches of continuous processing were carried out without replacing the carrier. That is, in each experimental example, platen adhesion on the carrier was checked 100 times in total.

In each experimental example, the difference in the minute waviness between the front surface and the back surface of the main surface was obtained using the substrates processed in the 20 th lot. Specifically, 2 substrates are sampled from each carrier, that is, 10 substrates in total are sampled, the average value of the minute undulations on the upper platen side (10 surface) and the average value of the minute undulations on the lower platen side (10 surface) are calculated, and the difference between these average values is calculated.

In table 1, the case where no protrusions mainly composed of glass exist on the surface of the carrier is used as a comparative example, and the cases where protrusions exist and the heights of the protrusions are different are used as examples 1 to 8. The ratio of the number of times of occurrence of sticking in table 1 is a relative value when the comparative example is "1.0".

[ Table 1]

As shown in table 1, a high effect of preventing adhesion was obtained only when the protrusions of 2 μm were formed on the surface of the carrier. In addition, if the height of the protrusions is 3 μm or more (examples 2 to 8), it is possible to substantially eliminate the adhesion of the carrier to the upper platen. On the other hand, if the height of the protrusion exceeds 50 μm (example 8), the difference between the front surface and the back surface in the surface shape of the substrate after processing is slightly larger than that of the other examples. Therefore, the height of the protrusions is preferably 50 μm or less. In example 8, since the height of the protrusions was too high, it is estimated that the surface of the polishing pad on the opposite upper platen side was damaged and the surface was roughened. From the results in Table 1, it was confirmed that the height of the protrusions is preferably 2 to 50 μm.

The minute undulations in table 1 were measured by an optical surface shape measuring device using a laser beam. The measurement method includes the steps of irradiating a laser beam of a predetermined wavelength onto the surface of the object to be measured at a predetermined angle, detecting the reflected light from the object to be measured, and obtaining height information of the main surface. The wave band of the micro-wave is 10-500 μm. In the present embodiment, the front and back surfaces of a glass substrate having a diameter of about 65mm were measured by using the range of 15mm to 30mm as the radius of the main surface as the measurement region, and the "difference" of the minute undulations of the front and back surfaces was calculated. When it is necessary to have the same processing quality on both surfaces as in the case of a substrate for a magnetic disk, if this difference becomes large, polishing is not good due to the influence of the main surface on which the fine fluctuation is large, and re-polishing is necessary, which is not preferable because productivity is deteriorated.

In example 8, it was confirmed that the same difference in the minute fluctuation was observed between the 1 st batch and the 10 th batch, and the result was 0.001 or less, which was a good result. Thus, it was confirmed that the difference of the minute undulations was generated when the long-term continuous processing was performed.

Therefore, according to the carrier 104 and the method for manufacturing the glass substrate 102 using the carrier 104 of the present embodiment, the adhesion of the carrier 104 to the upper platen 108 is prevented by the plurality of protrusions 136 existing on the upper surface 124 of the carrier 104, and further, the difference in the minute undulations between the upper surface and the lower surface of the glass substrate 102 is prevented from becoming large, so that the glass substrate 102 of high quality can be obtained.

Next, based on the conditions of example 5, the amount of epoxy resin etched in the sheet, which is a material of the carrier 104, was changed as appropriate, thereby producing the carrier 104 in which the width dimension of the protrusion 136 was changed. Thereafter, the surface was processed by a grinder so that the height of the protrusions 136 was uniform to 20 μm. Using these

carriers

104, 100 batches of continuous processing were performed in the same manner as described above. Table 2 summarizes the results.

[ Table 2]

	Width of the protrusion (mum)	Adhesion
			Example 9	25	Adhesion at run 90
Example 10	50	100 batches or more did not cause adhesion
			Example 11	100	No adhesion occurred in more than 100 batches
Practice ofExample 12	300	No adhesion occurred in more than 100 batches
			Example 13	600	No adhesion occurred in more than 100 batches
Example 14	900	No adhesion occurred in more than 100 batches

As is clear from examples 10 to 14, it was confirmed that the effect of suppressing the adhesion was maintained for a long time by setting the width of the protrusion 136 to 50 μm or more. In contrast, in example 14 in which the width of the projection was 900 μm, abnormal noise was detected during the machining. Therefore, it was confirmed that the thickness is preferably 600 μm or less from the viewpoint of suppressing abnormal noise.

(relationship with protrusion Density)

Based on the conditions of example 5, the density of protrusions (piece/mm) was prepared ² ) The carriers varied to 0.5, 1, 5, and 10, and 20 batches of substrates were continuously polished. Table 3 shows the experimental results. As seen from examples 15 to 18, no adhesion of the carrier to the upper platen occurred.

[ Table 3]

	Density of protrusions (pieces/mm) ² )	Adhesion after 20 batches processing
			Example 15	0.5	Is not generated
Example 16	1	Is not generated
			Example 17	5	Does not generate
Example 18	10	Is not generated

(relationship with area ratio of protrusion-forming region)

Carriers in which the ratio (%) of the area of the protrusion-forming region was changed to 10, 20, 75, and 100 were prepared based on the conditions of example 5, and 20 batches of substrates were continuously polished. Table 4 shows the experimental results. As is clear from examples 19 to 22, no sticking of the carrier to the upper platen occurred up to 20 batches.

[ Table 4]

(relationship with chopped glass fiber)

The surface of the carrier produced under the conditions of example 1 was treated with a liquid containing fluorosilicic acid, and then the surface was treated with a grinder. Thus, the glass fibers were protruded on the surface of the carrier, and a part of the glass fibers were cut, thereby preparing a carrier having the same average height of protrusion as that of example 1. Using this carrier, 20 batches of substrates were continuously polished. As a result, the ratio of the number of times of adhesion was 0.1, which was halved. In addition, as in the above, the carrier produced under the conditions of example 9 was treated, and after the continuous polishing treatment experiment, adhesion of 100 batches or more was not detected. From these results, it was confirmed that a higher adhesion preventing effect was further obtained by cutting a part of the glass fiber.

(relationship with concave part)

In the carrier of example 8, 3 kinds of carriers were prepared, i.e., recesses having a depth of 0.3, 10, or 30 μm, which were obtained by etching the resin in the protrusion forming region. Using these carriers, 20 batches of continuous polishing treatment of substrates were performed. As described above, regarding the substrates processed in the 20 th batch, differences in the minute waviness of the front surface and the back surface of the main surface were evaluated to be 0.0017, 0.0012, and 0.001 or less, respectively. In addition, no adhesion occurred. From this result, it was confirmed that by forming the protrusions in the recesses, the difference in the minute undulations of the front surface and the back surface can be reduced.

[ 2 nd embodiment ]

Embodiment 2 of the carrier of the present invention and a method for manufacturing a substrate using the carrier will be described. The same reference numerals are given to those parts overlapping with those in embodiment 1, and the description thereof is omitted.

Fig. 6 is a top view showing the carrier 104 of fig. 1. On the upper surface 124 of the carrier 104 representatively shown in the drawing, recesses 128 are provided in a plurality of regions 126 (protrusion forming regions) (see fig. 7 (b)). As shown, the plurality of regions 126 are located at locations other than the periphery 130 of the retention aperture 122 and are spaced apart from one another. In particular, it may be a region surrounded by at least 3 retaining holes 122 and discontinuous with the retaining holes 122.

Further, the contour forming the plurality of recesses 128 is constituted by a free curve, for example, formed so as not to contact the gear portion 115 formed on the outer periphery of the carrier 104. The area occupied by the entire plurality of recesses 128 is 5% or more of the entire upper surface 124 of the carrier 104, and the upper limit is set to 80% or less. In addition, a plurality ofThe area of the recess 128 is set to 1cm ² Above and 400cm ² The following ranges. The number of the recesses 128 having an area satisfying this range is preferably not less than 1/3 in all the recesses 128. More preferably not less than 1/2, and still more preferably all. When the amount is less than 1/3, the effect of suppressing the sticking may not be stably obtained.

Fig. 7 is a schematic diagram illustrating the recess 128 and its surroundings disposed on the upper surface 124 of the carrier 104 of fig. 6. Fig. 7 (a) is a schematic view typically showing a region 126 located on the upper surface 124 of the carrier 104. Fig. 7 (b) is a sectional view taken along line a-a of fig. 7 (a).

The region 126 shown in fig. 7 (a) includes a region surrounded by 3 holding

holes

122a, 122b, and 122c, and is discontinuous from these holding

holes

122a, 122b, and 122 c. As shown in fig. 7 (b), a recess 128 is provided in the region 126. The entire perimeter 132 of the recess 128 becomes the major surface 134 of the carrier 104. That is, the concave portion 128 is in the form of a pool or a bag and can store the polishing liquid. As shown in fig. 7 (b), the concave portion 128 is provided only on the upper surface 124 of the carrier 104 and not on the lower surface 135, but may be provided on both the upper and lower surfaces as long as the effect of suppressing the suction to the upper platen 108 side is not impaired. When the recessed portions 128 are provided on both the upper and lower surfaces, the area and the number of the recessed portions 128, the depth dimension Lc (see fig. 8 (b)), the region where the recessed portions 128 are formed, and the like may be appropriately adjusted for each surface.

Fig. 8 is a schematic diagram showing an enlarged B region of fig. 7 (a). Fig. 8 (a) is a plan view showing the B region in an enlarged manner. Fig. 8 (b) is a cross-sectional view taken along line C-C of fig. 8 (a). As shown in fig. 8 (a), the recess 128 is provided in the region 126 located outside the peripheral edge 130 of the holding hole 122. The depth Lc of the recess 128 shown in FIG. 8 (b) is set to 0.3 to 30 μm.

According to the carrier 104 of the present embodiment, the polishing liquid can be stored in the recessed portion 128 by forming the recessed portion 128 in the region 126 in the upper surface 124 of the carrier 104. Thereby, even when the carrier 104 attempts to closely adhere to the polishing pad 116 of the upper platen 108, the closely adhering area of the resins to each other can be reduced. Therefore, the adsorption force of the surface of the carrier 104 to the polishing pad 116 is reduced, and the effect of preventing adhesion (adsorption) is high.

Further, the contour of the recess 128 formed in the region 126 is constituted by a free curve, and is preferably formed so as not to contact the gear portion 115 of the carrier 104. Therefore, when the surface of the glass substrate 102 is polished, the polishing liquid can be reliably accumulated in the concave portion 128, and the effect of preventing sticking is high.

The area occupied by the entire plurality of recesses 128 is preferably 5% to 80% of the area of the entire surface of the carrier 104. If the ratio of the total area of the recesses 128 is less than 5%, the effect of preventing the sticking may not be stably obtained for a long period of time due to the adhesion of the polishing agent or the like to the surface of the carrier 104. On the other hand, if the ratio of the total area of the concave portions 128 is too large, the carrier 104 warps, and the glass substrate 102 as a substrate to be polished may be detached from the carrier 104. Therefore, the upper limit of the proportion of the area is preferably 80% or less. In addition, when the ratio of the area is small, the concave portions are distributed around the vicinity of the outer periphery of the carrier, and the effect of preventing the adhesion can be improved even with a small area.

In addition, it is preferable that at least 1/3 or more recesses among all the recesses 128 have an area of 1cm ² Above and 400cm ² The following. Assuming that the area of the recess 128 is less than 1cm ² Then, the effect of preventing adhesion may not be sufficiently obtained. Further, it is more preferable that the area of the recess 128 is 2cm ² The above. On the other hand, if the area of the recess 128 is too large, the carrier 104 warps, and the glass substrate 102 may be detached from the carrier 104. Therefore, the upper limit of the area of the recess 128 is preferably 400cm ² The following.

Further, since the depth dimension Lc of the concave portion 128 shown in fig. 8 (b) is set to 0.3 to 30 μm (see table 1), the polishing liquid can be sufficiently stored in the concave portion 128. Therefore, adhesion of the carrier 104 can be prevented, and warpage of the carrier 104 and detachment of the glass substrate 102 from the carrier 104 during the polishing process can be prevented.

[ examples ]

Examples of the present invention will be described below by way of example, but the present invention is not limited to the following examples.

(preparation of substrate to be processed)

A target substrate was a glass substrate for a magnetic disk having a nominal 2.5 size (diameter of about 65mm), and a substrate obtained after completion of the first polishing treatment using a polishing liquid containing cerium oxide abrasive grains was prepared by a known method.

(preparation of test Carrier)

The carrier is produced by using a sheet in which glass fibers are woven and epoxy resin is impregnated, and shaping the sheet. Then, by appropriately using the above method, additional processing was performed on 1 surface of the carrier to form a plurality of recesses having the specifications shown in table 1.

(Experimental conditions)

The second polishing is performed on the substrate to be processed by the above-described or known method except for the following. As the polishing machine, both surfaces of the substrate to be processed are simultaneously polished using the above-described double-side polishing apparatus in which polishing pads are adhered to upper and lower platens, respectively. The polishing pad is a polyurethane resin polishing pad, and is a suede-type polishing pad having a surface layer with a nap formed with a plurality of fine elongated holes (naps) formed in the thickness direction by a foaming agent. The polishing agent is a polishing liquid containing colloidal silica particles having an average particle diameter (D50) of 30nm as polishing abrasive grains. The carrier is provided in the grinder so that the surface having the recess faces upward.

In the polishing process 1 time (1 batch), 5 carriers were provided so that 10 substrates could be held per 1 carrier, and both main surfaces of 50 substrates were polished at one time. The substrate to be processed was replaced, and 20 batches of continuous processing were carried out without replacing the carrier. That is, in each experimental example, platen adhesion on the carrier was checked 100 times in total.

In Table 5, the case where no recess is present on the surface of the carrier is referred to as comparative example 2, and the cases where recesses are present and the depths of the recesses are different are referred to as examples 15 to 21. The ratio of the number of times of occurrence of sticking in table 5 is a relative value when comparative example 2 is assumed to be "1.0". Further, the recess formation of each embodimentNot in contact with the gear portion of the carrier. In addition, in the recesses of each embodiment, the ratio of the area occupied in the entire surface of one surface of the carrier excluding the holding holes was set to 30%, and the area of all the recesses was set to 1cm ² The above.

The deformation of the carrier in table 5 is a result of observing warpage, deformation, and a surface state after the end of 100 batches by removing the carrier from the double-side polishing apparatus. Further, if the carrier is deformed such as warped, the substrate may be detached from the holding hole during the polishing process if the carrier is used continuously, which is not preferable.

[ Table 5]

As shown in Table 5, it is preferable that the depth of the concave portion is 0.3 μm or more (examples 23 to 29) because the ratio of the number of times of occurrence of sticking can be reduced. On the other hand, if the depth of the recess exceeded 30 μm (example 29), warpage of the carrier was confirmed. Therefore, the depth of the recess is preferably 30 μm or less. Thus, it was confirmed from the results of Table 5 that the depth of the concave portion is preferably 0.3 to 30 μm.

Therefore, according to the carrier 104 and the method of manufacturing the glass substrate 102 using the carrier 104 of the present embodiment, sticking (adsorption) can be prevented by the plurality of concave portions 128 provided in the region 126 of the upper surface 124 of the carrier 104. Further, since the carrier 104 is prevented from warping during the polishing process and the glass substrate 102 is prevented from being detached from the carrier 104, high-quality glass substrates 102 can be obtained at a higher yield than in the conventional art without lowering productivity.

While the preferred embodiments of the present invention have been described above with reference to the drawings, it is apparent that the present invention is not limited to the above embodiments, and various modifications and alterations can be made by those skilled in the art within the scope of the claims.

Industrial applicability

The present invention can be used as a carrier used for polishing the main surface of a plate-like substrate such as a substrate for a magnetic recording medium, a glass for a liquid crystal screen, or a silicon wafer, and a method for producing a substrate using the carrier.

Claims

1. A carrier for polishing or grinding, having a holding hole for holding a substrate,

a plurality of recesses are provided on at least one surface of the carrier in a region other than a peripheral edge of the holding hole,

the carrier is made of a material in which glass fibers are woven and impregnated with a resin.

2. The carrier of claim 1,

at least 1 of the plurality of recesses is formed such that a contour forming the recess does not contact the gear portion of the carrier.

3. The carrier according to claim 1 or 2,

the depth of the recess is 0.3 [ mu ] m or more.

4. The carrier according to claim 1 or 2,

the profile forming the recess consists of a free curve.

5. The carrier according to claim 1 or 2,

the area occupied by the whole of the plurality of concave portions is 5% or more of the area of the whole of at least one surface of the carrier.

6. The carrier according to claim 1 or 2,

at least a recess portion of the plurality of recess portions having an area of not less than 1/3 is 1cm ² The above.

7. The carrier according to claim 1 or 2,

the plurality of recesses are formed to have a predetermined width so as to avoid the periphery of the holding hole.

8. The carrier according to claim 1 or 2,

a plurality of projections mainly composed of glass are present in at least a part of the recess.

9. A method for manufacturing a substrate, comprising:

holding a substrate in the holding hole of the carrier according to any one of claims 1 to 8, and polishing or grinding both surfaces of the substrate simultaneously by sandwiching the substrate with upper and lower platens having polishing pads or grinding pads.

10. The method for manufacturing a substrate according to claim 9, wherein the substrate is a substrate for a magnetic disk.