WO2015194278A1

WO2015194278A1 - Polishing pad and method for producing polishing pad

Info

Publication number: WO2015194278A1
Application number: PCT/JP2015/063234
Authority: WO
Inventors: 史博向; 歳和田浦
Original assignee: バンドー化学株式会社
Priority date: 2014-06-17
Filing date: 2015-05-07
Publication date: 2015-12-23
Also published as: KR20170013315A; TW201600233A; JPWO2015194278A1; CN106457523A

Abstract

The purpose of the present invention is to provide a polishing pad that is capable of achieving a good balance between processing efficiency and finish flatness at high levels. A polishing pad according to the present invention has a base and a polishing layer that is laminated on the front surface of the base. This polishing pad is characterized in that: the polishing layer comprises a binder that is mainly composed of a resin or an inorganic material and diamond abrasive grains that are dispersed in the binder; and the diamond abrasive grains have an average shape factor of from 1 to 1.33 (inclusive). It is preferable that a main component of the binder is a thermosetting resin or a photocurable resin. It is preferable that a main component of the binder is a silicate salt. It is preferable that the polishing layer has a plurality of projected portions in the front surface and the plurality of projected portions are regularly arranged. It is preferable that an adhesive layer is provided on the back surface of the base. It is preferable that the adhesive layer is configured of an adhesive. It is preferable that the base has flexibility or ductility.

Description

Polishing pad and polishing pad manufacturing method

The present invention relates to a polishing pad and a method for manufacturing the polishing pad.

In recent years, electronic devices such as hard disks have been refined. As a substrate material for such an electronic device, glass or the like is used in consideration of rigidity, impact resistance, and heat resistance that can be reduced in size and thickness.

Such processing of a substrate (object to be polished) is mainly divided into lapping processing and polishing processing. First, physical lapping using hard particles such as diamond is performed in lapping, and substrate thickness control and planarization are performed. Next, in the polishing process, a chemical polishing process using fine particles such as ceria is performed, and the planarization accuracy of the substrate surface is improved.

Generally, when trying to improve the flattening accuracy of the finish, the processing time tends to be long, and the processing efficiency and the flattening accuracy are in a trade-off relationship. For this reason, it is difficult to achieve both processing efficiency and flattening accuracy. On the other hand, a polishing pad having a polishing layer containing a binder and abrasive grains and having a convex portion has been proposed in order to achieve both processing efficiency at the time of lapping and flattening accuracy ( (See JP-T 2002-542057).

However, even if this conventional polishing pad is used, it cannot be said that the processing efficiency and the flattening accuracy are sufficiently compatible, and a higher level of processing efficiency and finished flatness are both required. .

JP-T 2002-542057

The present invention has been made on the basis of the above-described circumstances, and an object thereof is to provide a polishing pad capable of achieving both processing efficiency and finished flatness at a high level.

As a result of intensive studies, the present inventors have found that the processing efficiency of the object to be polished and the finished flatness can be compatible at a high level by using diamond grains having an average shape factor within a certain range, and the present invention has been completed. I let you.

That is, the invention made to solve the above problems is a polishing pad having a base material and a polishing layer laminated on the surface thereof, wherein the polishing layer is a binder mainly composed of a resin or an inorganic substance. And diamond abrasive grains dispersed in the binder, wherein the diamond abrasive grains have an average shape factor of 1 or more and 1.33 or less.

Since the polishing pad has diamond abrasive grains having an average shape factor within the above range, the polishing pad can achieve both high processing efficiency and finished flatness of the object to be polished. Therefore, the polishing pad can flatten the surface of the object to be polished such as a glass substrate in a short time.

The main component of the binder is preferably a thermosetting resin or a photocurable resin. Thus, when the binder is composed mainly of a thermosetting resin or a photocurable resin, it is easy to ensure good dispersibility of diamond abrasive grains and good adhesion to the substrate when the binder is constituted. Moreover, it is easy to form a polishing layer. As a result, the durability of the polishing layer can be improved and the processing efficiency during polishing can be improved.

The main component of the binder is preferably silicate. Thus, the abrasive particle retention power of a polishing layer can be improved by making the main component of a binder into a silicate.

The polishing layer may have a plurality of convex portions on the surface, and the plurality of convex portions may be regularly arranged. Thus, the polishing layer has a plurality of convex portions on the surface, and the plurality of convex portions are regularly arranged, so that the anisotropy of polishing is reduced and the surface to be polished is further flattened. Can be easily converted.

It is good to have an adhesive layer on the back side of the substrate. Thus, by having an adhesive layer on the back side of the substrate, the polishing pad can be easily and reliably fixed to a support for mounting the polishing pad on a polishing apparatus.

The adhesive layer is preferably composed of an adhesive. Thus, by comprising the said adhesive layer with an adhesive, since a polishing pad can be peeled off from a support body and can be replaced, reuse of a polishing pad and a support body becomes easy.

It is preferable that the base material has flexibility or ductility. Thus, since the said base material has flexibility or ductility, since a polishing pad follows the surface shape of a to-be-polished body and it becomes easy to contact a grinding | polishing surface and a to-be-polished body, processing efficiency further improves.

Another invention made to solve the above problems is a method for producing a polishing pad having a substrate and a polishing layer laminated on the surface thereof, and the polishing layer is printed on the polishing layer composition. A polishing layer composition comprising a binder component mainly composed of a resin or an inorganic substance and diamond abrasive grains having an average shape factor of 1 or more and 1.33 or less. It is characterized by.

The manufacturing method of the polishing pad has high manufacturing efficiency because the polishing layer can be formed by printing the composition for polishing layer. Moreover, since the manufacturing method of the said polishing pad forms the polishing layer which has a diamond abrasive grain whose average shape factor is 1 or more and 1.33 or less, it is compatible with the processing efficiency and finished flatness of a to-be-polished body at a high level. A polishing pad can be manufactured.

Here, the “average shape factor” is (D ² / A) where D (μm) is the diameter of a circle circumscribing the projection surface of the abrasive grains, and A (μm ² ) is the area of the projection surface of the abrasive grains. ) × (π / 4).

As described above, according to the polishing pad of the present invention, both processing efficiency and finished flatness can be achieved at a high level. Therefore, the polishing pad can flatten the surface of the object to be polished such as a glass substrate in a short time.

1 is a schematic plan view showing a polishing pad according to an embodiment of the present invention. FIG. 1B is a schematic end view taken along line AA in FIG. 1A. It is a typical end elevation showing a polishing pad of an embodiment different from Drawing 1B.

[First embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

<Polishing pad>
A polishing pad 1 shown in FIGS. 1A and 1B includes a resin-made base material 10, a polishing layer 20 laminated on the front surface side of the base material 10, and an adhesive layer 30 laminated on the back surface side of the base material 10. Is provided.

(Base material)
The substrate 10 is a plate-like member for supporting the polishing layer 20.

Although it does not specifically limit as a material of the said base material 10, A polyethylene terephthalate (PET), a polypropylene (PP), a polyethylene (PE), a polyimide (PI), a polyethylene naphthalate (PEN), an aramid, aluminum, copper etc. are mentioned. It is done. Among these, PET and PI that have good adhesion to the polishing layer 20 are preferable. Moreover, the process which improves adhesiveness, such as a chemical process, a corona process, and a primer process, may be performed on the surface of the base material 10.

The base material 10 may be flexible or ductile. Thus, since the base material 10 has flexibility or ductility, the polishing pad 1 follows the surface shape of the object to be polished, and the polishing surface and the object to be polished are easily in contact with each other, thereby further improving the processing efficiency. Examples of the material of the flexible base material 10 include PET and PI. Moreover, aluminum and copper can be mentioned as a material of the base material 10 which has ductility.

The shape and size of the substrate 10 are not particularly limited, but may be, for example, a 150 mm × 150 mm square shape or an annular shape having an outer diameter of 637 mm and an inner diameter of 234 mm. Moreover, the structure by which the several base material 10 juxtaposed on the plane is supported by a single support body may be sufficient.

The average thickness of the substrate 10 is not particularly limited, but can be, for example, 75 μm or more and 1 mm or less. When the average thickness of the substrate 10 is less than the lower limit, the polishing pad 1 may have insufficient strength and flatness. On the other hand, when the average thickness of the substrate 10 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and may be difficult to handle.

(Polishing layer)
The polishing layer 20 has a binder 21 and diamond abrasive grains 22 dispersed in the binder 21. The polishing layer 20 has a plurality of convex portions 23 on the surface.

The average thickness of the polishing layer 20 (average thickness of only the convex portion 23) is not particularly limited, but the lower limit of the average thickness of the polishing layer 20 is preferably 100 μm, and more preferably 130 μm. The upper limit of the average thickness of the polishing layer 20 is preferably 1000 μm, and more preferably 800 μm. When the average thickness of the polishing layer 20 is less than the lower limit, the durability of the polishing layer 20 may be insufficient. On the other hand, when the average thickness of the polishing layer 20 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and may be difficult to handle.

(binder)
The binder 21 contains a resin or an inorganic material as a main component.

The resin is not particularly limited, but a thermosetting resin and a photocurable resin are preferable. Examples of the thermosetting resin include polyurethane, polyphenol, epoxy resin, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacryl, acrylic ester resin, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polyamide. it can. Examples of the photocurable resin include acrylic ester resins, urethane acrylate resins, vinyl ester resins, polyester alkyds, and the like. Of these, thermosetting epoxy resins are preferred. When the thermosetting epoxy resin constitutes the binder 21, it is easy to ensure good dispersibility of the diamond abrasive grains 22 and good adhesion to the substrate 10. Moreover, even if it uses the resin which added the hardening | curing agent to the ultraviolet curable resin which added the ultraviolet curing agent, or thermoplastic resins, such as a polyacryl, the good dispersibility of the diamond abrasive grain 22 and the favorable to the base material 10 are similarly obtained. Adhesion is easy to ensure. The resin of the binder 21 may be at least partially crosslinked.

Examples of the inorganic substance include silicate, phosphate, and polyvalent metal alkoxide. Of these, silicates that are excellent in the abrasive particle retention of the polishing layer 20 are preferred.

The binder 21 may appropriately contain various auxiliaries and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a colorant depending on the purpose.

(Abrasive grains)
The lower limit of the average particle diameter of the diamond abrasive grains 22 is preferably 1 μm and more preferably 3 μm. Moreover, as an upper limit of the average particle diameter of the said diamond

abrasive grain

22, 20 micrometers is preferable and 15 micrometers is more preferable. When the average particle diameter of the diamond abrasive grains 22 is less than the lower limit, the polishing rate may be insufficient. On the other hand, when the average particle diameter of the diamond abrasive grains 22 exceeds the upper limit, the object to be polished may be damaged.

The lower limit of the average shape factor of the diamond abrasive grains 22 is 1. Moreover, as an upper limit of the average shape factor of the said diamond abrasive grain 22, it is 1.33, and 1.3 is more preferable. When the average shape factor of the diamond abrasive grains 22 exceeds the above upper limit, it may be difficult to achieve both high processing efficiency and finished flatness of the object to be polished. The average shape factor of the diamond abrasive grains 22 is not less than 1 from the definition.

The lower limit of the content of the diamond abrasive grains 22 with respect to the polishing layer 20 is preferably 35% by mass, and more preferably 40% by mass. Moreover, as an upper limit of content with respect to the polishing layer 20 of the said diamond abrasive grain 22, 70 mass% is preferable and 65 mass% is more preferable. When the content of the diamond abrasive grains 22 with respect to the polishing layer 20 is less than the lower limit, the polishing power of the polishing layer 20 may be insufficient. On the other hand, when the content of the diamond abrasive grains 22 with respect to the polishing layer 20 exceeds the upper limit, the object to be polished may be damaged.

(Convex part)
The polishing layer 20 has a plurality of convex portions 23 arranged on the surface in a lattice pattern with equal intervals. The shapes of the plurality of convex portions 23 are regularly arranged block pattern shapes. The bottom surface of the portion (groove portion) other than the convex portion 23 of the polishing layer 20 is constituted by the surface of the substrate 10.

The lower limit of the average area of the convex portion 23 is preferably 0.5 mm ^2, 1 mm ² is more preferable. The upper limit of the average area of the convex portions 23 is preferably 3 mm ^2, 2.5 mm ² is more preferable. When the average area of the convex portion 23 is less than the lower limit, the convex portion 23 of the polishing layer 20 may be peeled off. On the other hand, when the average area of the convex portion 23 exceeds the above upper limit, the frictional resistance during polishing of the polishing layer 20 increases, and the object to be polished may be damaged.

The lower limit of the area occupation ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 is preferably 15% and more preferably 20%. Moreover, as an upper limit of the area occupation rate with respect to the said whole polishing layer 20 of the said some convex-shaped

part

23, 40% is preferable and 35% is more preferable. When the area occupation ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 is less than the lower limit, the convex portions 23 of the polishing layer 20 may be peeled off. On the other hand, when the area occupancy ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 exceeds the upper limit, the frictional resistance during polishing of the polishing layer 20 is increased and the object to be polished may be damaged. The “area of the entire polishing layer” is a concept including the area of voids in the polishing layer.

(Adhesive layer)
The adhesive layer 30 is a layer that supports the polishing pad 1 and fixes the polishing pad 1 to a support for mounting on the polishing apparatus.

The adhesive used for the adhesive layer 30 is not particularly limited, and examples thereof include a reactive adhesive, an instantaneous adhesive, a hot melt adhesive, and an adhesive.

As the adhesive used for the adhesive layer 30, a pressure-sensitive adhesive is preferable. By using a pressure-sensitive adhesive as the adhesive used for the adhesive layer 30, the polishing pad 1 and the support can be easily reused because the polishing pad 1 can be peeled off from the support and replaced. Such an adhesive is not particularly limited. For example, an acrylic adhesive, an acrylic-rubber adhesive, a natural rubber adhesive, a synthetic rubber adhesive such as butyl rubber, a silicone adhesive, and a polyurethane adhesive. Agents, epoxy adhesives, polyethylene adhesives, polyester adhesives, and the like.

The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, more preferably 0.1 mm. Moreover, as a minimum of the average thickness of the contact bonding layer 30, 0.3 mm is preferable and 0.2 mm is more preferable. When the average thickness of the adhesive layer 30 is less than the above lower limit, the adhesive force is insufficient and the polishing pad 1 may be peeled off from the support. On the other hand, when the average thickness of the adhesive layer 30 exceeds the above upper limit, for example, due to the thickness of the adhesive layer 30, there is a risk that workability may be lowered, such as causing trouble when the polishing pad 1 is cut into a desired shape.

(Polishing pad manufacturing method)
The polishing pad 1 can be manufactured by a step of preparing a polishing layer composition and a step of forming the polishing layer 20 by printing the polishing layer composition.

First, in the polishing layer composition preparation step, a solution in which the polishing layer composition (the material for forming the binder 21 and the diamond abrasive grains 22) is dispersed in a solvent is prepared as a coating solution. The solvent is not particularly limited as long as the material for forming the binder 21 is soluble. Specifically, methyl ethyl ketone (MEK), isophorone, terpineol, N methylpyrrolidone, cyclohexanone, propylene carbonate, or the like can be used. In order to control the viscosity and fluidity of the coating liquid, a diluent such as water, alcohol, ketone, acetate ester and aromatic compound may be added.

Next, in the polishing layer formation step, the coating liquid prepared in the polishing layer composition preparation step is applied to the surface of the base material 10, and the polishing layer 20 having the convex portions 23 is formed by a printing method. In order to form the convex portion 23, a mask having a shape corresponding to the shape of the convex portion 23 is used. The coating liquid is applied (printed) using this mask. As this coating method, for example, bar coating, reverse roll coating, knife coating, screen printing, gravure coating, die coating and the like can be used. Then, the polishing layer 20 is formed by drying and reaction-curing the applied coating liquid. Specifically, for example, after the solvent of the coating liquid is evaporated by heat of 100 ° C. or higher and 120 ° C. or lower, the solvent of the coating liquid is cured by heat of 80 ° C. or higher and 120 ° C. or lower to form the binder 21.

(advantage)
In the polishing pad 1, since the polishing layer 20 has diamond abrasive grains 22 having an average shape factor of 1 or more and 1.33 or less, the processing efficiency of the object to be polished and the finished flatness can be achieved at a high level. Therefore, the polishing pad 1 can flatten the surface of the object to be polished such as a glass substrate in a short time. Further, the polishing pad 1 has a block pattern shape in which the polishing layer 20 has a plurality of convex portions 23 on the surface, and the shapes of the plurality of convex portions 23 are regularly arranged. The anisotropy is reduced, and the surface to be polished can be further flattened. Moreover, the said polishing pad 1 can be easily and reliably fixed to the support body with which the said polishing pad 1 is mounted | worn with a polishing apparatus by having the contact bonding layer 30 on the back surface side of the said base material 10. FIG. Furthermore, since the manufacturing method of the said polishing pad 1 can form the polishing layer 20 by printing of the composition for polishing layers, manufacturing efficiency is good.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be implemented in a mode in which various changes and improvements are made in addition to the above-described mode. In the above-described embodiment, the convex portions are configured in an equally spaced grid pattern. However, the grid spacing does not have to be evenly spaced. For example, the spacing may be changed between the vertical direction and the horizontal direction. However, when the intervals between the convex portions are different, anisotropy may occur in the polishing, and therefore equal intervals are preferable. Further, the planar shape of the convex portion may not be a lattice shape, and may be, for example, a shape in which a polygon other than a quadrangle is repeated, a circular shape, a shape having a plurality of parallel lines, or the like.

Moreover, in the said embodiment, although it was set as the structure which the bottom face of said several groove part is the surface of a base material, even if the depth of a groove part is smaller than the average thickness of an abrasive layer, and a groove part does not reach the surface of a base material, Good. In that case, the depth of the groove can be 50% or more of the average thickness of the polishing layer. When the depth of the groove is less than the above lower limit, the groove due to wear may be lost, and the polishing pad may be inferior in durability.

In the above embodiment, a method using a mask was shown as a method for forming the convex portion. However, after the polishing layer composition is printed on the entire surface of the substrate, the convex portion is formed by etching or laser processing. May be.

In the above embodiment, the polishing layer has a convex portion, but the convex portion is not an essential component. For example, a polishing layer may be uniformly laminated on the substrate surface.

Further, as shown in FIG. 2, the polishing pad 2 may include a support 40 laminated via an adhesive layer 30 on the back side and a second adhesive layer 31 laminated on the back side of the support 40. . When the polishing pad 2 includes the support body 40, the polishing pad 2 can be easily handled.

Examples of the material of the support 40 include thermoplastic resins such as polypropylene, polyethylene, polytetrafluoroethylene, and polyvinyl chloride, and engineering plastics such as polycarbonate, polyamide, and polyethylene terephthalate. By using such a material for the support 40, the support 40 has flexibility, the polishing pad 2 follows the surface shape of the object to be polished, and the polishing surface and the object to be polished come into contact with each other. Since it becomes easy, processing efficiency further improves.

The average thickness of the support 40 can be, for example, 0.5 mm or more and 2 mm or less. When the average thickness of the support 40 is less than the lower limit, the strength of the polishing pad 2 may be insufficient. On the other hand, when the average thickness of the support 40 exceeds the upper limit, it may be difficult to attach the support 40 to a polishing apparatus or the flexibility of the support 40 may be insufficient.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]
Diamond abrasive grains ("LS series" from Lands) were prepared, and average particle diameter and average shape factor were measured using Malvern "Morphology G3". The results are shown in Table 1.

Add epoxy solvent ("JER828" from Mitsubishi Chemical Corporation), diluting solvent (isophorone), curing agent ("YH306" from Mitsubishi Chemical Corporation and "Cureazole 1B2MZ" from Shikoku Kasei Corporation) and the above diamond abrasive The mixture was mixed and adjusted so that the content of the diamond abrasive grains with respect to the polishing layer was 55% by mass to obtain a coating solution.

A PET film (“Melenex S” manufactured by Teijin DuPont Films Ltd.) having an average thickness of 75 μm was used as a substrate, and a polishing layer having convex portions was formed on the surface of the substrate by printing. In addition, the convex part was formed in the grinding | polishing layer by using the mask corresponding to a convex part as a printing pattern. The convex portion had a square shape with a side of 1.5 mm in plan view and an average thickness of 135 μm. The convex portions were in the form of regularly arranged block patterns, and the area occupation ratio of the convex portions with respect to the entire polishing layer was 36%.

Further, a hard vinyl chloride resin plate (“SP770” from Takiron Co., Ltd.) having an average thickness of 1 mm is used as a support that supports the polishing pad and is fixed to the polishing apparatus, and the back surface of the substrate and the surface of the support are It bonded together with the adhesive material of average thickness 130micrometer. A double-sided tape (“# 5605HGD” from Sekisui Chemical Co., Ltd.) was used as the adhesive material.

[Examples 2 and 3, Comparative Examples 1 to 3]
Examples 2 and 3 and Comparative Examples 1 to 3 were obtained by changing the average grain size and average shape factor of the diamond abrasive grains of Example 1 as shown in Table 1.

[Example 4]
The same diamond abrasive grains as in Example 1 were used, and the silicate ("Sodium silicate seal brand" of Fuji Chemical Co., Ltd.) and the curing agent ("Recassette No. 5" of Kobe Riken Co., Ltd.) were used. )) Was mixed and adjusted so that the content of diamond abrasive grains was 65% by mass, the content of silicate was 34% by mass, and the content of curing agent was 1% by mass to obtain a molding liquid. .

The molding liquid is poured into a polytetrafluoroethylene resin mold having a side of 3 mm and a depth of 1 mm, dehydrated at 90 ° C. for 1 hour or more, then released from the resin mold, and fired at 300 ° C. for 1 hour. A shaped part was produced.

An aluminum plate having an average thickness of 500 μm was used as the base material, and the convex portions obtained by the firing were arranged in a block pattern at a pitch of 5 mm on the surface of the base material. Bonded with ceramic D "). The area occupation ratio of the convex portion with respect to the entire polishing layer is 36%. Then, the convex part surface was planarized using WA # 800 grindstone.

[Example 5, Comparative Example 4]
Example 5 and Comparative Example 4 were obtained by changing the average particle size and average shape factor of the diamond abrasive grains of Example 4 as shown in Table 1.

[Polishing conditions]
The glass substrate was polished using the polishing pads obtained in Examples 1 to 5 and Comparative Examples 1 to 4. Three soda lime glasses (made by Hiraoka Special Glass Manufacturing Co., Ltd.) having a diameter of 6.25 cm and a specific gravity of 2.4 were used for the glass substrate. A commercially available double-side polishing machine (Nippon Engis Co., Ltd. “EJD-5B-3W”) was used for the polishing. The carrier of the double-side polishing machine is an epoxy glass having a thickness of 0.6 mm. Polishing was performed at a polishing pressure of 200 g / cm ² for 15 minutes under the conditions of an upper surface plate rotation speed of 60 rpm, a lower surface plate rotation speed of 90 rpm, and a SUN gear rotation speed of 30 rpm. At that time, 120 cc of “Tool Mate GR-20” supplied by Moresco Co., Ltd. was supplied as a coolant.

[Evaluation methods]
For the glass substrates polished using the polishing pads of Examples 1 to 5 and Comparative Examples 1 to 4, the polishing rate and the surface roughness (Ra) of the polished object were determined, and the processing efficiency and the finished flatness As the evaluation of coexistence, the value (compatibility level) obtained by dividing the polishing rate by the surface roughness (Ra) was evaluated. This level of compatibility becomes a large value when the polishing rate is high and the processing efficiency is high, and when the surface roughness is low and the finished flatness is high, and shows high compatibility between the working efficiency and the finished flatness. The results are shown in Table 1. The polishing rate and the surface roughness (Ra) were determined by the following methods.

(Polishing rate)
The polishing rate was calculated by dividing the weight change (g) of the glass substrate before and after polishing by the surface area (cm ² ) of the glass substrate, the specific gravity (g / cm ³ ) of the glass substrate, and the polishing time (minutes).

(Surface roughness)
Regarding the surface roughness, a contact type surface roughness meter (“S-3000” manufactured by Mitutoyo Corporation) was used to measure any four locations on the front and back surfaces, and the average value of a total of 8 locations was determined.

The coexistence level obtained by dividing the polishing rate by Ra from Table 1 is high in Examples 1 to 5 in which the average shape factor is 1.33 or less, regardless of the average grain size or the amount of the diamond abrasive grains. Low in Comparative Examples 1 to 4 where the shape factor exceeds 1.33. Therefore, it can be seen that the processing efficiency and the finished flatness can be compatible at a high level by setting the average shape factor of the diamond abrasive grains to 1.33 or less.

According to the polishing pad of the present invention, both processing efficiency and finished flatness can be achieved at a high level. Therefore, the polishing pad can flatten the surface of the object to be polished such as a glass substrate in a short time.

DESCRIPTION OF

SYMBOLS

1, 2 Polishing pad 10 Base material 20 Polishing layer 21 Binder 22 Diamond abrasive grain 23 Convex part 30 Adhesive layer 31 Second adhesive layer 40 Support body

Claims

A polishing pad having a substrate and a polishing layer laminated on the surface side thereof,
The polishing layer has a binder mainly composed of a resin or an inorganic substance and diamond abrasive grains dispersed in the binder,
An average shape factor of the diamond abrasive grains is 1 or more and 1.33 or less.
The polishing pad according to claim 1, wherein the main component of the binder is a thermosetting resin or a photocurable resin.
The polishing pad according to claim 1, wherein the main component of the binder is silicate.
The polishing layer has a plurality of convex portions on the surface,
The polishing pad according to claim 1, wherein the plurality of convex portions are regularly arranged.
The polishing pad according to any one of claims 1 to 4, further comprising an adhesive layer on the back side of the substrate.
The polishing pad according to claim 5, wherein the adhesive layer is composed of an adhesive.
The polishing pad according to any one of claims 1 to 6, wherein the substrate has flexibility or ductility.
A method for producing a polishing pad having a substrate and a polishing layer laminated on the surface side,
Comprising the step of forming the polishing layer by printing the composition for polishing layer,
In the polishing layer forming step, a polishing pad composition comprising a binder component mainly composed of a resin or an inorganic substance and diamond abrasive grains having an average shape factor of 1 or more and 1.33 or less is used. Production method.