JP2003062754A - Polishing tool and manufacturing method of polishing tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing tool capable of efficiently carrying out a reliable mirror surface machining usable to a general polishing machine and a lapping machine. SOLUTION: In a polishing tool 10 whose polishing material is fixed on a base material 16, secondary particles 12 formed by aggregating minute primary particles 11 such as colloidal silica and hyperfine ceria are uniformly contained as the polishing material 1 in a short seat type base material such as polyurethane resin, which enables improvement of both working efficiency and working surface quality. Furthermore, when being used to an general polishing machine, good conformability to a working surface is secured, which leads to reliable polishing work according to a shape of the worked surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing tool and a method for manufacturing a polishing tool, and more particularly, it is suitable for finishing hard and brittle materials such as silicon and glass, and metal materials such as steel and aluminum. The present invention relates to a polishing tool and a method for manufacturing the same.

[0002]

2. Description of the Related Art Polishing (mirror finishing) using a polishing machine is used for the final finishing of the surface of parts made of various hard and brittle materials such as silicon wafers and glass disks, and metallic materials such as steel and aluminum. Has been done. That is, for example, a so-called abrasive slurry, in which fine free abrasive grains such as diamond paste are dispersed in a solvent as an abrasive to form a paste or slurry,
Polishing the processed surface by rotating the rotary table while supplying it to the gap between the polishing cloth attached to the rotary table of the polishing machine and the processed surface of the workpiece (hereinafter referred to as "processed surface" as appropriate). Was. In this processing method, it is easy to use fine free abrasive grains as an abrasive, so it is possible to easily obtain a mirror-finished machined surface with excellent machined surface quality and to use a large amount of abrasive slurry. There is an advantage that stable processing characteristics (processing efficiency, processing surface roughness, etc.) can be maintained. Therefore, polishing work using the abrasive slurry has been performed at many work sites.

However, in the polishing process using the abrasive slurry, since a large amount of the abrasive slurry is used, there are disadvantages that the surrounding environment is contaminated and the load on the environment due to waste liquid treatment increases. To improve the machining efficiency, the polishing speed (rotational speed of the rotary table) may be increased. However, when the polishing speed exceeds a certain level, the centrifugal force reduces the amount of abrasive supplied to the processed surface, Then, the phenomenon that the processing efficiency is lowered occurs. That is, in the polishing process using the abrasive slurry, there is a limit to the improvement of processing efficiency, which is one obstacle to the improvement of productivity.

Therefore, there is a demand for a machining tool which can obtain an excellent machined surface roughness equivalent to the machined surface roughness by polishing (mirror processed surface roughness) without using an abrasive slurry. It's getting higher. In particular, so-called fixed-abrasive machining tools, in which the abrasive grains are fixed to the base material of the tool, have come to the attention.

In the polishing process using abrasive grains, in order to obtain a machined surface having a small surface roughness, it is usually advantageous to use fine abrasive grains in order to reduce the cutting depth of the abrasive grains. However, in the fixed-abrasive machining tool, if abrasive grains having a grain size of several μm or less are used in order to obtain a machined surface roughness in a mirror surface state, when the abrasive grains are used, the base material (or bonding material) of the fixed-abrasive machining tool and The frequency of contact with the surface to be machined increases, and as a result, the machining resistance rapidly increases, the abrasive grains fall off, and in the worst case, the machine becomes incapable of machining. Further, even if measures are taken to suppress the contact between the base material (or the binder) and the processed surface, the particle size of the abrasive grains is small, so that the processing efficiency decreases with time. That is, it was difficult to satisfy both the improvement of the machining efficiency and the improvement of the quality of the machined surface at the same time.

Therefore, in order to solve these problems,
A fixed-abrasive machining tool has been developed that uses an aggregate of fine abrasive grains. The purpose of this is to obtain a machined surface having a small surface roughness by the action of fine abrasive grains and to improve the machining efficiency by the aggregate of the abrasive grains (aggregated abrasive grains).

A fixed-abrasive machining tool using an aggregate of fine abrasive grains is disclosed, for example, in JP-A-8-155840 (hereinafter referred to as "first known example") and JP-A-2000-.
198073 (hereinafter, referred to as "second known example") and JP-A-2000-237962 (hereinafter,
“Third known example”) and the like.

In the first known example, a binder (vitrified bond binder) is blended, and the agglomerated abrasive grains are formed by aggregating the abrasive grains to 4 to 8 times their diameter and molding the hardened resin together with a hard resin. And a method for manufacturing the same.
The second known example discloses a polishing grindstone in which agglomerated abrasive particles in which ultrafine abrasive particles are agglomerated are molded together with a hard resin. A third known example discloses a so-called polishing film in which granulated particles formed by aggregating fine primary particles are fixed on a polyethylene terephthalate film as a base material with a resin as a binder. .

[0009]

However, the whetstone disclosed in the first known example or the second known example described above is attached to the surface plate of a polishing machine which is usually used in polishing. When polishing is performed, the hardness of the grindstone is too high, and therefore the grindstone may not cut into the processed surface. Further, since the polishing machine is more likely to generate vibration than the grinding machine, a machining mark (scratch) or the like may occur on the machined surface due to vibration of the grindstone.

On the other hand, the polishing film disclosed in the third known example has a structure in which a polishing layer is formed on a film-shaped substrate, and is usually used in a throw-away method, that is, a disposable method. Therefore, when used as a tool for polishing, the tool life is short,
There is an inconvenience that the tool cost becomes high. Further, when the polishing film is attached to the surface plate of the polishing machine to perform the polishing process, the number of tool replacements increases and the work efficiency decreases.

The present invention has been made in view of the above circumstances, and a first object thereof is to provide a polishing tool which can be used for an ordinary polishing machine or a lapping machine to efficiently perform stable mirror surface processing. To provide.

A second object of the present invention is to provide a method for manufacturing a polishing tool which can be used in a normal polishing machine or lapping machine to perform stable mirror surface processing.

[0013]

According to a first aspect of the present invention, there is provided an abrasive tool in which an abrasive material is fixed to a base material, wherein the base material is a soft member, and the abrasive material is provided in the base material. The polishing tool is characterized by containing secondary particles formed by aggregating fine primary particles in a dispersed manner.

According to this, since the secondary particles in which fine primary particles are aggregated are used as the abrasive, it is possible to improve the processing efficiency by the secondary particles and the surface quality of the processed by the primary particles. That is, it is possible to satisfy both the improvement of the machining efficiency and the improvement of the quality of the machined surface at the same time. Also, when the abrasive is a single particle, large crushing of the abrasive occurs during processing, so the abrasion of the abrasive progresses rapidly, but when the abrasive is an aggregate (secondary particle), the abrasive is Since the wear of the polishing tool gradually progresses, the wear of the polishing tool can be suppressed.

Further, since a softer base material is used than in the case of a grinding wheel, when used in a normal polishing machine, for example, it is more compatible with the machined surface than the grinding wheel and the shape of the machined surface is better. It is possible to perform stable polishing processing following the above.

Further, since the abrasive material is dispersed and contained in the base material, unlike the case of the abrasive film, when the abrasive tool is worn by the polishing process, new abrasive materials appear one after another on the surface of the abrasive tool. . Therefore, it can be used for polishing for a longer time than the polishing film. That is, since the life of the polishing tool (the tool life) is long, the cost (tool cost) is reduced, and the burden on the operator such as the replacement of the tool can be reduced.

Therefore, according to the invention of claim 1,
It is possible to efficiently perform stable mirror surface processing by using a normal polishing machine or lapping machine.

In this case, as in the polishing tool according to the second aspect, the average particle diameter of the primary particles can be 1 μm or less.

In each of the polishing tools described in claims 1 and 2, as in the polishing tool described in claim 3, the average particle size of the secondary particles is within the range of 1 to 30 μm. it can.

In each of the polishing tools described in claims 1 to 3, the content of the secondary particles is in the range of 5 to 60% by volume of the whole, as in the polishing tool described in claim 4. Can be

In each of the polishing tools described in claims 1 to 4, as in the polishing tool described in claim 5, the secondary particles are
It may be that the binder is not included therein.

In each of the polishing tools described in claims 1 to 5, as in the polishing tool described in claim 6, at least one of an organic substance and an inorganic substance is further contained as an additive in the base material. Can be

In this case, as in the polishing tool according to claim 7, the additive may contain at least one of powder and fiber.

In this case, as in the polishing tool according to claim 8, the additive may contain a powder, and the average particle diameter of the powder may be within the range of 0.3 to 3 μm.

In the polishing tool according to the seventh aspect, as in the polishing tool according to the ninth aspect, the additive contains fibers, and the fibers have an average minor axis of 0.1 to 1 μm and an average major axis of 0. .3 to 5 μm, respectively.

In each of the polishing tools described in claims 6 to 9, the content of the additive is in the range of 5 to 30% by volume of the whole, as in the polishing tool described in claim 10. can do.

In each of the polishing tools described in claims 1 to 10, as in the polishing tool described in claim 11, the base material may further include independent pores. .

In each of the polishing tools described in claims 1 to 11, the polishing tool described in claim 12, the base material may be in the form of a sheet.

A thirteenth aspect of the present invention is a method for manufacturing an abrasive tool in which an abrasive is fixed to a sheet-like base material, which comprises secondary particles formed by aggregating fine primary particles. A kneading step of kneading the abrasive and the base material to obtain a kneaded material; a molding step of molding the kneaded material into a predetermined shape;
A method for manufacturing a polishing tool including the following.

According to this, the secondary particles formed by aggregating the fine primary particles and the substrate are kneaded to obtain a kneaded product in which the secondary particles are uniformly dispersed in the substrate (kneading step ). Then, the kneaded product is molded into a predetermined shape (sheet shape) (molding step) to obtain a polishing tool in which secondary particles as abrasives are uniformly dispersed and contained in a sheet-shaped base material. It can be manufactured.

A fourteenth aspect of the present invention is a method for manufacturing an abrasive tool in which an abrasive is fixed to a base material, wherein the abrasive comprises secondary particles formed by aggregating fine primary particles. A polishing tool including a kneading step of kneading a kneading agent and a binder to obtain a kneaded material; an impregnation step of impregnating the kneaded material into a base material; and a molding step of molding a base material impregnated with the kneaded material. Is a manufacturing method.

According to this, the secondary particles formed by aggregating the fine primary particles and the binder are kneaded to obtain a kneaded product in which the secondary particles are uniformly dispersed in the binder (kneading step ). Then, by impregnating this kneaded material into a base material (impregnation step) and molding this base material (molding step), secondary particles as abrasives are uniformly dispersed and fixed in the base material. Can be manufactured.

In the method for manufacturing each of the polishing tools according to claims 13 and 14, as in the method for manufacturing the polishing tool according to claim 15, in the kneading step, at least one of an organic substance and an inorganic substance is further kneaded. Can be

In the method for manufacturing each of the polishing tools according to claims 13 to 15, as in the method for manufacturing the polishing tool according to claim 16, in the kneading step, the foaming agent is further kneaded. be able to.

In the method for manufacturing each of the polishing tools according to claims 13 to 16, as in the method for manufacturing the polishing tool according to claim 17, fine primary particles are aggregated to form two particles prior to the kneading step. The method may further include a granulation step of forming secondary particles.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments and examples of the present invention will be described below.

FIG. 1A is a block diagram of a polishing tool 10 according to an embodiment of the present invention. This polishing tool 10
Is composed of secondary particles 12 which are agglomerates of fine primary particles, an additive 14, a base material 16 and independent pores 18.

The secondary particles 12 are generally hard inorganic substances depending on the object to be processed, and as shown in the enlarged view of FIG. 1 (B), fine particles having an average particle size of 1 μm or less are used. Aggregates in which the primary particles 11 are aggregated and have an average particle diameter within the range of 1 to 30 μm are suitable. Normal secondary particles 12
As a material to be used for silica, silica (silicon oxide), ceria (cerium oxide), diamond, cBN (cubic boron nitride), alumina (aluminum oxide), silicon carbide and the like can be used, but the materials are not limited to these. is not. Although not normally used as an abrasive, it is also possible to use an aggregate (aggregated powder) used for applications such as filters and spacers. The secondary particles 1
The content of 2 is preferably in the range of 5 to 60% by volume of the entire polishing tool. In addition, inside the secondary particles 12,
It is desirable not to include inclusions such as a binder. Therefore, for example, when a commercially available agglomerated powder is used, it is preferable to perform heat treatment in advance.

The secondary particles 12 are formed by, for example, a general sol-gel method in which the sol containing the primary particles is hydrolyzed to aggregate the primary particles 11 into a predetermined size. As a result, the secondary particles 12 containing no inclusions such as a binder inside
Is obtained. The shape of the secondary particles 12 may be spherical, granular or amorphous.

As a method of forming the secondary particles 12,
It is not limited to the formation method utilizing precipitation by an aqueous solution reaction such as the sol-gel method, but depending on the material, the formation method utilizing precipitation from an aqueous solution (for example, spray dryer method, freeze drying method, solvent drying method). , A solid formation method (for example, thermal decomposition of solid matter, solid-phase reaction), a formation method from gas (for example, evaporation-condensation, vapor-phase decomposition method, vapor-phase reaction) and the like can be used. Moreover, you may use the impact method which makes primary particles collide with each other using a high-speed air stream. As a result, it suffices that secondary particles 12 having a predetermined average particle diameter be obtained without including inclusions such as a binder inside.

In particular, colloidal silica, fumed silica and colloidal ceria are ultrafine particles, have a chemical activity, and exhibit a mechanochemical action on the processed surface, so that the primary particles 11 constituting the secondary particles 12 are formed. Is a very preferable material.

As the additive 14, powders or fibers of organic or inorganic substances can be used. Suitable powders have an average particle size in the range of 0.3 to 3 μm,
Suitable fibers are those having an average short diameter of 0.1 to 1 μm and an average long diameter of 0.3 to 5 μm. As the organic powder, for example, acrylic or nylon powder can be used, and as the inorganic powder, for example, solid lubricant such as molybdenum disulfide, diamond, cB, etc.
Powders of N, silica, alumina, silicon carbide, iron oxide and the like can be used. Fibers such as acrylic and nylon can be used as the organic fibers, and fibers such as alumina, silicon carbide, and carbon can be used as the inorganic fibers. The additive 14 is not limited to one kind, and a plurality of materials may be used.

The content of the additive 14 is preferably in the range of 5 to 30% by volume of the entire polishing tool, and the type and shape of the additive 14, the content of the secondary particles 12 and the polishing tool 10 are preferable. The optimum content rate is determined by the mechanical properties required for. In addition, in the polishing tool 10 of the present embodiment,
Although the additive 14 is contained, it may not be necessarily contained as long as the characteristics required for the polishing tool are satisfied.

Further, the secondary particles 12 and the additives 14 may be subjected to surface modification (surface treatment) such as coupling treatment (for example, silane coupling treatment or titanate coupling treatment) as an example. . As a result, the bond with the base material 16 is further strengthened, and the effect as a filler can be expected. Here, depending on the types of the secondary particles 12 and the additives 14, the material of the base material 16, and the intended modification contents (for example, improvement in rigidity and impact strength), the optimum type of treatment, The processing method and the like are determined.

As the base material 16, a soft thermosetting resin,
A thermoplastic resin, a photocurable resin, or the like can be used. It should be noted that the base material 16 may have independent holes 18 as shown in FIG. The polishing debris generated by the processing is captured by the holes 18, so that the polishing debris can be prevented from adhering to the secondary particles 12. This hole 18
Is, for example, a foaming agent (for example, a physical foaming agent such as butane gas or a chemical foaming agent such as asodicarbonamide).
Can be easily formed by adding or adding a foamable material such as urethane foam resin to the base material 16.

Next, a method for manufacturing the polishing tool of the present invention will be briefly described.

As a first embodiment, a method of manufacturing a polishing tool in the case where a sheet-shaped material such as a woven cloth or a nonwoven cloth is used as a base material will be described. In this case, a binder is required to fix the secondary particles and the additives in the base material.

First, fine primary particles are aggregated by a sol-gel method or the like to form secondary particles (granulating step). Then, to the secondary particles, an additive made of at least one of an organic material and an inorganic material, a binder and a foaming agent are added, and a mixture of these is kneaded using a general-purpose stirrer, etc., and the secondary particles are added to the binder. A kneaded product in which the product and the foaming agent are uniformly dispersed is obtained (kneading step). A base material (woven fabric or non-woven fabric) is immersed in this kneaded product to impregnate the kneaded product in the base material (impregnation step). Further, the base material is heated at a predetermined temperature for a predetermined time to solidify the binder, and the secondary particles and the additives are fixed in the base material. This makes it possible to manufacture a polishing tool in which the secondary particles and additives are uniformly dispersed and contained in the base material.

In the first embodiment, the woven or non-woven fabric as the base material is generally formed of a material used for chemical fibers such as nylon and polyester. However, the present invention is not limited to these, as long as a soft woven or non-woven fabric can be formed.

In the first embodiment, the base material is immersed in the kneaded product in the impregnation step, but the present invention is not limited to this. For example, the kneaded product may be sprayed onto the base material. good. This is because it is sufficient that the kneaded product penetrates into the voids in the base material. Further, the base material may be subjected in advance to a surface treatment for improving the wettability with the kneaded product. In this case, the optimum surface treatment method is selected according to the type of binder.

Next, as a second embodiment, a method for manufacturing a polishing tool in the case of integrally molding a base material and secondary particles (and additives) into a sheet will be described. In this case, the binder for fixing the secondary particles and the additives in the base material is not always necessary.

Fine primary particles are aggregated by a sol-gel method or the like to form secondary particles (granulating step). To the secondary particles, an additive comprising at least one of an organic substance and an inorganic substance, a base material and a foaming agent are added, and a mixture of these is kneaded using a general-purpose stirrer, etc. And a kneaded product in which the foaming agent is uniformly dispersed is obtained (kneading step). Next, the kneaded product is poured into a mold having a predetermined shape, and the mold is heated at a predetermined temperature for a predetermined time to solidify and mold the base material (molding step). by this,
It is possible to manufacture a polishing tool in which secondary particles and additives are uniformly dispersed and contained in a sheet-shaped base material.

In the second embodiment, the kneaded product is poured into the mold in the molding process, but the mold is not limited to this, and for example, a ceramic mold may be used. . This is because it is sufficient if it can be molded into a predetermined shape.

In each of the above-mentioned embodiments, it is desirable that the average particle diameter of the primary particles is 1 μm or less in the granulation step, and the average particle diameter of the secondary particles is within the range of 1 to 30 μm. Is desirable. The granulation step can be omitted when a commercially available agglomerated powder is used.

Although the additives are kneaded in the kneading step in each of the above embodiments, the additives may not be included if it is not necessary to adjust the mechanical properties of the polishing tool. is there.

Further, in each of the above-mentioned embodiments, the foaming agent is kneaded in the kneading step, but it is not necessary when it is not necessary to generate the independent pores.

Further, in each of the above-mentioned embodiments, the surface modification treatment described above may be applied to the surface of the secondary particles and the additives prior to the kneading step.

Next, examples of the present invention will be described.

Example 1 In Example 1, ultrafine colloidal silica particles having an average particle size of 50 nm were used as primary particles, and a urethane resin was used as a base material.

The ultrafine colloidal silica particles were aggregated by a sol-gel method to obtain secondary particles of silica having an average particle size of 15 μm and containing no inclusions such as a binder inside. That is, in Example 1, first, ultrafine colloidal silica particles and a solution containing water and alcohol were mixed at a predetermined ratio and hydrolyzed to form a gel, and the silica particles were aggregated. Then, when the aggregate of silica particles reached a desired size, the aggregate was placed in a constant temperature bath at 50 ° C. to 65 ° C. to evaporate water, organic solvent, etc. contained in the aggregate. Furthermore, the particle size distribution of the aggregate was measured using a laser diffraction / scattering type particle size distribution measuring device, and the frequency integrated value was 50%.
It was confirmed that the particle size (median size) was 15 μm. The aggregate thus formed was used as a secondary particle.

Then, the secondary particles and the urethane resin were weighed to form a mixture. Here, the amount was determined so that the secondary particles occupy 35% by volume of the entire polishing tool. Also,
At this time, a foaming agent was also added to the mixture in order to form independent pores in the urethane resin.

Next, using a general-purpose stirrer, the secondary particles and the foaming agent were uniformly dispersed in the urethane resin by 6
The mixture was kneaded at 0 rpm for 15 minutes to give a kneaded product. Then, in order to form this kneaded product into a sheet having a diameter of 450 mm, it was poured into a predetermined mold and then the mold was heated at 110 ° C. for 8 hours to accelerate the polymerization of the urethane resin.

When the polymerization of the urethane resin was almost completed, the urethane resin was taken out of the mold to obtain a polishing tool having a predetermined shape.

The polishing tool thus prepared was mounted on a normal polishing machine to polish a silicon wafer having a pre-processed surface as shown in FIG. 2 (A). The silicon wafer is preprocessed with a grindstone corresponding to # 2000.

As a result of this polishing, the processing surface roughness without processing marks was 20 nm within a processing time of 10 minutes.
A mirror surface of Ry or less could be obtained. Then, after further polishing the other silicon wafers,
Even with the 20th sheet, the processing efficiency does not decrease, and
As shown in, the machined surface roughness is 2 without machining marks.
A mirror surface of 0 nmRy or less could be obtained. Furthermore, as shown in FIG. 3, even with the 25th sheet, a processed surface roughness of 30 nmRy or less could be obtained. In addition, the processed surface roughness was measured by using Futamari Surf S4C manufactured by Thera Hopson.

Example 2 In Example 2, ultrafine ceria particles having an average particle size of 0.1 μm were used as primary particles, and carbon fibers having an average minor axis of 0.5 μm and an average major axis of 2 μm were used as additives. As the base material, a sheet-shaped or roll-paper-shaped non-woven fabric of polyester fiber was used. An acrylic resin was used as a binder for the base material, the secondary particles and the additive.

The ultrafine ceria particles were aggregated by the sol-gel method to obtain secondary particles of ceria having an average particle size of 20 μm and containing no inclusions such as binder.

Then, the secondary particles, the carbon fibers and the acrylic resin were weighed to form a mixture. Here, the respective amounts were determined so that the secondary particles occupy 40% by volume of the entire polishing tool and the carbon fibers occupy 20% by volume of the entire polishing tool.

Next, a general-purpose stirrer was used to knead the mixture so that the secondary particles and the carbon fibers were uniformly dispersed in the acrylic resin, to obtain a kneaded product.

Then, a non-woven fabric of polyester fiber having a predetermined shape was immersed in the kneaded product, and the non-woven fabric was impregnated with the kneaded product.

Then, this non-woven fabric was heated at 100 ° C. for 6 hours to cure the acrylic resin into a predetermined shape to obtain a polishing tool.

The polishing tool thus prepared was mounted on a usual polishing machine to polish a lapping-finished glass disk having a surface roughness of 2 μmRy. As a result, the processing surface roughness is 20 nmR in 25 minutes processing time.
A mirror surface of y or less could be obtained. Further, when another glass disk was subsequently subjected to polishing processing, almost no decrease in processing efficiency or processed surface roughness was observed even with the 20th glass disk.

[Comparative Example 1] In Comparative Example 1, ultrafine colloidal silica particles having an average particle diameter of 50 nm are used as primary particles, copper powder having an average particle diameter of 3 μm is used as an additive, and a grinding stone is generally used as a base material. The phenolic resin used as the binding material of was used.

The ultrafine colloidal silica particles were aggregated by a sol-gel method to obtain secondary particles of silica having an average particle diameter of 15 μm and containing no inclusions such as a binder.

Then, the secondary particles, the copper powder and the phenol resin were weighed and made into a mixture. Here, the respective amounts were determined so that the secondary particles accounted for 35% by volume of the entire grinding wheel and the copper powder occupied 15% by volume of the entire grinding wheel.

Next, using a general-purpose stirrer, the above mixture was kneaded so that the secondary particles and the copper powder were uniformly dispersed in the phenol resin to obtain a kneaded product.

Then, after the kneaded product was poured into a predetermined mold, the mold was heated at 150 ° C. for 4 hours to cure the phenol resin.

When the curing of the phenol resin was almost completed, the phenol resin was taken out of the mold and molded into a predetermined shape to obtain a grinding wheel.

The grinding stone thus prepared was mounted on a usual polishing machine to polish a lapping-finished silicon wafer. As a result, it was possible to obtain a mirror surface with no processing marks on some silicon wafers in a processing time of 10 minutes, but on most silicon wafers, a processed surface with a lot of scratches with a processed surface roughness of about 0.2 μmRy. Became.

Comparative Example 2 In Comparative Example 2, ultrafine ceria particles having an average particle diameter of 0.1 μm were used as primary particles, and carbon fibers having an average short diameter of 0.5 μm and an average long diameter of 2 μm were used as additives. A film-shaped polyethylene terephthalate (commonly called PET) having a thickness of about 75 μm was used as the substrate. An acrylic resin was used as a binder for the base material, the secondary particles and the additive.

The ultrafine ceria particles were aggregated by the sol-gel method to obtain secondary particles of ceria having an average particle size of 20 μm and containing no inclusions such as binder.

Then, the secondary particles, the carbon fibers and the acrylic resin were weighed to form a mixture. Here, the respective amounts were determined so that the secondary particles occupy 40% by volume of the entire polishing layer and the carbon fibers occupy 20% by volume of the entire polishing layer.

Next, using a general-purpose stirrer, the above mixture was kneaded so that the secondary particles and the carbon fiber were uniformly dispersed in the acrylic resin to obtain a kneaded product.

Then, the wire kneaded product was applied onto the polyethylene terephthalate film using a wire bar coater, and then heated at 100 ° C. for 6 hours in a thermostat to cure the acrylic resin to obtain a polishing film. . The thickness of the polishing layer in this polishing film was almost the same as the maximum particle size of the secondary particles.

The thus-prepared polishing film was mounted on a usual polishing machine to polish a lapping-finished glass disk. As a result, it was possible to obtain a mirror surface having a processed surface roughness of 10 nmRy or less in a processing time of 25 minutes. However, when other glass discs were subsequently subjected to polishing, when the five glass discs were subjected to polishing, the polishing layer of the polishing film disappeared due to wear and the tool life was reached, as shown in FIG. It was

As described above, according to the polishing tool of Example 1, the average particle size produced by aggregating ultrafine silica particles having an average particle size of 50 nm as primary particles is 15 μm.
The secondary particles of m are used as abrasives, and the content is 3
Since it is dispersed and fixed in the base material of the polyurethane resin so as to be 5% by volume, it is possible to improve the processing efficiency by the secondary particles and the processed surface quality by the primary particles. That is, it is possible to satisfy both the improvement of the machining efficiency and the improvement of the quality of the machined surface at the same time. Also, when the abrasive is a single particle, large crushing of the abrasive occurs during processing, so the abrasion of the abrasive progresses rapidly, but when the abrasive is an aggregate (secondary particle), the abrasive is Since the wear of the polishing tool gradually progresses, the wear of the polishing tool can be suppressed.

Further, according to the polishing tool of Example 1, as the polishing tool wears due to the polishing process, new secondary particles appear on the surface of the polishing tool one after another. Therefore, it can be used for long-time processing. That is, since the tool life is long, the tool cost is reduced, and the burden on the operator such as tool replacement can be reduced.

Furthermore, according to the polishing tool of Example 1,
Since the urethane resin, which is a soft member, is used as the base material, it is soft as a polishing tool, has good compatibility with the machined surface, and can easily follow the shape of the machined surface. In addition, in the conventional polishing machine, when used in place of, for example, a polishing cloth, the base material can absorb the vibration of the polishing machine, and as shown in FIG. An excellent machined surface can be stably obtained. On the other hand, the grinding wheel shown in Comparative Example 1 is
As shown in FIG. 5, although the primary particles and the secondary particles are the same as those of the polishing tool of Example 1, the base material is hard, so that it is not sufficiently compatible with the processed surface, Further, the vibration of the polishing machine is transmitted to the processing surface as it is.
Therefore, in the grinding wheel shown in Comparative Example 1, the machining mark (scratch) is frequently generated on the machined surface.

Further, according to the polishing tool of Example 1, since the foaming agent is added to the mixture, independent pores are uniformly formed in the base material after molding. As a result, it is possible to prevent the polishing dust generated by the polishing process from being trapped in the pores and attached to the secondary particles.

In addition, according to the polishing tool of Example 2, the secondary particles having an average particle size of 20 μm prepared by aggregating ultrafine ceria particles having an average particle size of 0.1 μm as primary particles are used as the abrasive. Since the non-woven fabric of polyester fiber as the base material is impregnated so that the content rate is 40% by volume of the entire polishing tool, the processing efficiency by the secondary particles and the surface quality by the primary particles are improved. be able to.
That is, it is possible to satisfy both the improvement of the machining efficiency and the improvement of the quality of the machined surface at the same time.

Further, according to the polishing tool of Example 2,
With the abrasion of the polishing tool due to the polishing process, new secondary particles can appear on the surface of the polishing tool one after another. Therefore, as shown in FIG. 6, since the tool life is long, the cost of the tool is reduced, the burden on the operator such as the replacement of the tool can be reduced, and the work efficiency can be improved.
On the other hand, in the polishing film shown in Comparative Example 2 above, as shown in FIG.
As shown in FIG. 3, although the primary particles and the secondary particles were the same as those in the polishing tool of Example 2, P as the base material was used.
Since the secondary particles are fixed on the ET film as an abrasive layer with an acrylic resin, when the PET film is deformed due to vibration of the polishing machine, the abrasion of the abrasive layer becomes uneven and the secondary A region in which particles are partially depleted may appear in a short time. Therefore, the processing efficiency is reduced and it becomes difficult to obtain the required processed surface quality.

Further, according to the polishing tool of Example 2,
The carbon fiber having an average minor axis of 0.5 μm and an average major axis of 2 μm is added as an additive so that the content rate is 20% by volume of the entire polishing tool, so that the base material of the polishing tool is 1%.
Even when the polishing tool is made of only one kind of material, the mechanical properties of the polishing tool can be adjusted to a predetermined value, and the polishing tool can have abrasion resistance and the like required for the polishing tool. Moreover, heat resistance can be improved. In addition, the dispersed state of the secondary particles is further homogenized by including the additive, and the interval between the secondary particles exposed on the surface of the base material can be appropriately maintained. Is secured.

When the additive is in the form of fiber, the same effect as described above can be obtained as long as the average minor axis is 0.1 to 1 μm and the average major axis is 0.3 to 5 μm. However, if the average minor axis of the fibers is less than 0.1 μm, the effect of the above-mentioned addition is small, and if the average minor axis exceeds 1 μm, the frequency of scratches on the processed surface due to the additive increases. Similarly, when the average major axis is less than 0.3 μm, the effect of the above-mentioned addition is small, and the average major axis is 5 μm.
If it exceeds, the frequency of scratches on the processed surface due to the additive increases. In the case of fibers, even if the amount added is the same, it is possible to impart a hardness higher than that of powder to the polishing tool.

When the additive is in the form of powder, the same effect as described above can be obtained as long as the average particle size is within the range of 0.3 to 3 μm. However, if the average particle size of the powder is less than 0.3 μm, the effect of the above-described addition is small, and if the average particle size exceeds 3 μm, the frequency of scratches on the processed surface due to the additive increases.

Further, the content of the additive is 5% of the total amount of the polishing tool.
Within the range of ˜30% by volume, the same effect as described above can be obtained. However, if the content of the additive is less than 5% by volume of the whole polishing tool, the effect of the above-mentioned addition is small, and if it exceeds 30% by volume, the amount of the base material is small and the rigidity of the polishing tool is reduced. However, the frequency with which the polishing tool is deformed or broken is increased, and the strength for fixing the secondary particles is significantly reduced.

Further, according to each of the above-mentioned examples, since the secondary particles do not contain inclusions such as a binder inside,
It is possible to prevent the adhesion of polishing dust due to inclusions,
It becomes possible to maintain the processing ability of secondary particles. As a result, the stability of polishing can be improved.

In each of the above examples, if the average particle diameter of the primary particles is 1 μm or less, similarly excellent processed surface can be surely obtained. However, when the average particle size of the primary particles exceeds 1 μm, as an example, as shown in FIG. 7A for the case where the average particle size of the primary particles is 2 μm, scratches are generated on the processed surface and The frequency of degrading becomes high.

The secondary particles also have an average particle size of 1 to
Within the range of 30 μm, similarly excellent processed surface quality can be efficiently obtained. However, when the average particle size of the secondary particles is less than 1 μm, as an example, as shown in FIG. 7B for the case where the average particle size of the secondary particles is 0.5 μm, the polishing tool is not used during the polishing process. Frequent occurrences occur, such as slipping on the work surface to cause so-called burning, or direct contact between the base material (or binder) of the polishing tool and the work surface, resulting in a sharp increase in working resistance. On the other hand, when the average particle size of the secondary particles exceeds 30 μm, as an example, as shown in FIG. 7C for the case where the average particle size of the secondary particles is 40 μm, scratches are generated on the processed surface, The quality of the machined surface is reduced more frequently.

Further, in each of the above-mentioned examples, if the content of the secondary particles is within the range of 5 to 60% by volume of the entire polishing tool, similarly excellent processed surface quality can be efficiently obtained. However, the content of secondary particles is 5
If it is less than volume%, the secondary particles (abrasive material) are small, so that the processing efficiency is remarkably reduced. On the other hand, if it exceeds 60% by volume, the rigidity of the polishing tool is reduced due to the small amount of the base material. The frequency with which the polishing tool is deformed or broken is increased, and the strength for fixing the secondary particles is significantly reduced.

[0100]

As described above, according to the polishing tool of the present invention, secondary particles formed by aggregating fine primary particles are contained as an abrasive in a soft base material. Therefore, there is an effect that stable mirror surface processing can be efficiently performed by using an ordinary polishing machine or lapping machine.

Further, according to the method for manufacturing a polishing tool according to the present invention, it is possible to manufacture a polishing tool which can be used in an ordinary polishing machine or lapping machine to efficiently perform stable mirror surface processing. There is an effect.

[Brief description of drawings]

1A is a configuration diagram of a polishing tool as an embodiment of the present invention, and FIG. 1B is an enlarged view of secondary particles 12 in FIG. 1A.

FIG. 2 (A) is a diagram (photograph as a substitute for a drawing) showing an example of a photograph of a surface state of a silicon wafer before polishing, which is observed with a microscope, and FIG. It is a figure (drawing substitute photograph) which shows an example of the photograph which observed the surface state after the polishing process of the 20th silicon wafer which carried out the polishing process with the polishing tool with the microscope.

FIG. 3 is a diagram for explaining the result of polishing by the polishing tool of Example 1.

FIG. 4 is a diagram (photograph as a substitute for a drawing) showing an example of a photograph obtained by observing a surface state of a polishing film after polishing five glass disks with a microscope in Comparative Example 2.

FIG. 5 is a diagram for explaining the difference between Example 1 and Comparative Example 1.

FIG. 6 is a diagram for explaining the difference between Example 2 and Comparative Example 2.

FIG. 7A is a diagram showing an example of a photograph obtained by observing a surface state of a silicon wafer after polishing with a microscope when the average particle diameter of primary particles is 2 μm (drawing substitute photograph). 7B, the average particle diameter of the secondary particles is 0.
FIG. 7C is a diagram (photograph as a substitute for a drawing) showing an example of a photograph of a surface state of a silicon wafer after being subjected to polishing in the case of 5 μm (drawing substitute photograph), and FIG. It is a figure (drawing substitute photograph) which shows an example of the photograph which observed the surface state of the silicon wafer after grind processing in the case of 40 micrometers with a microscope.

[Explanation of symbols]

10 ... Abrasive tool, 11 ... Primary particles, 12 ... Secondary particles, 14
… Additives, 16… Base materials, 18… Independent pores.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhiro Tani             3-47-12 Miyasaka, Setagaya-ku, Tokyo F-term (reference) 3C063 AA03 AB07 BB01 BB08 BB25                       BD01 BD02 BG01 BG22 FF23

Claims (17)

[Claims] 1. A polishing tool in which an abrasive is fixed to a base material, wherein the base material is a soft member, and a secondary material formed by aggregating fine primary particles as the abrasive material in the base material. A polishing tool containing particles dispersed therein. 2. The polishing tool according to claim 1, wherein the average particle diameter of the primary particles is 1 μm or less. 3. The average particle diameter of the secondary particles is 1 to 30 μm.
The polishing tool according to claim 1 or 2, wherein the polishing tool is in the range. 4. The content of the secondary particles is 5 to 6 of the whole.
4. It is within the range of 0% by volume.
The polishing tool according to any one of 1. 5. The polishing tool according to claim 1, wherein the secondary particles do not contain a binder inside. 6. The polishing tool according to claim 1, wherein the base material further contains at least one of an organic substance and an inorganic substance as an additive. 7. The polishing tool according to claim 6, wherein the additive contains at least one of powder and fiber. 8. The polishing tool according to claim 7, wherein the additive contains powder, and the average particle diameter of the powder is in the range of 0.3 to 3 μm. 9. The additive according to claim 7, wherein the additive includes fibers, and the average minor axis of the fibers is within a range of 0.1 to 1 μm and the average major axis is within a range of 0.3 to 5 μm. Polishing tool. 10. The content of the additive is 5 to 3 of the whole.
It is in the range of 0% by volume.
The polishing tool according to any one of 1. 11. The polishing tool according to claim 1, wherein the base material further contains independent pores. 12. The polishing tool according to claim 1, wherein the base material has a sheet shape. 13. A method of manufacturing a polishing tool in which an abrasive is fixed to a sheet-shaped substrate, the abrasive and the substrate comprising secondary particles formed by aggregating fine primary particles. And a forming step of forming the kneaded material into a predetermined shape, and a kneading step of kneading the kneaded material into a kneaded material. 14. A method of manufacturing a polishing tool in which an abrasive is fixed to a base material, wherein the abrasive composed of secondary particles formed by aggregating fine primary particles and a binder are kneaded. A method of manufacturing a polishing tool, comprising: a kneading step of forming a kneaded material; an impregnation step of impregnating the kneaded material into a base material; and a molding step of molding a base material impregnated with the kneaded material. 15. The method of manufacturing a polishing tool according to claim 13, wherein in the kneading step, at least one of an organic substance and an inorganic substance is further kneaded. 16. The method for manufacturing a polishing tool according to claim 13, wherein the foaming agent is further kneaded in the kneading step. 17. The method according to claim 13, further comprising a granulation step of aggregating fine primary particles to form secondary particles prior to the kneading step. Polishing tool manufacturing method.