JP4292179B2 - Whetstone - Google Patents

Description

  The present invention relates to a grindstone for polishing a surface of a workpiece.

  A grindstone is a tool formed by solidifying hard particles, that is, abrasive grains with a binder. There are two types of processing using a grindstone: grinding processing and polishing processing. Routine processing is customarily referred to as grinding processing, and finishing processing is referred to as polishing processing. In these processes, the surface of the workpiece, i.e., the surface to be processed, is moved by the abrasive grains by relatively moving the grindstone and the workpiece while the grindstone is pressed against the workpiece, i.e., the workpiece. The two are functionally synonymous, and in this specification, both are referred to as polishing.

  For polishing using a grindstone, cylindrical polishing for processing the cylindrical outer peripheral surface of the workpiece, internal polishing for processing the cylindrical inner peripheral surface of the workpiece, and processing the flat surface of the workpiece There is a surface polishing process. As a grindstone for processing the outer peripheral surface or the inner peripheral surface, a grindstone provided with a cylindrical processed surface is used. In addition, as a grindstone for machining a flat surface, a cylindrical grindstone having a machining surface provided on the outer peripheral surface or a cup-shaped, ring-shaped and disc-shaped grindstone having a machining surface provided on a flat end surface is used. .

In order to polish the surface of the silicon wafer, an attempt to use a grindstone has been made as described in Patent Document 1. A grindstone having a flat working surface is used for such flat processing, and CMP processing is performed by applying a slurry in which an abrasive is suspended to the processing surface as a polishing liquid, and the polishing liquid is applied to the processing surface. Therefore, the polishing liquid is supplied through the pores of the grindstone.
JP 2002-187062 A

  The grindstone is attached to a polishing holder or a polishing head and is driven to rotate. To apply a polishing liquid having loose abrasive grains or a slurry having a chemical abrasive to the work surface through the pores of the grindstone When the dimension between the base end surface of the grindstone, that is, the surface abutted against the polishing head, and the machining surface is increased, the area where the pores are connected to each other decreases, the air flow resistance of the polishing liquid increases, and the polishing liquid is processed into the grindstone. Since the surface cannot be transmitted through the pores, it is necessary to reduce the thickness dimension between the base end surface of the grindstone and the processed surface. If the thickness is reduced, the airflow resistance of the polishing liquid and slurry is reduced, and it is possible to permeate the pores and discharge the polishing liquid etc. from the processing surface. However, the grinding stone is deformed by the pressure of the polishing liquid, and high-precision polishing is performed. It becomes impossible to do.

  The objective of this invention is providing the grindstone which can perform a highly accurate grinding | polishing process.

The grindstone of the present invention is a grindstone for polishing a work surface of a workpiece, and is provided with a work surface for polishing the work surface, which is formed of a porous body having abrasive grains, a binder, and pores. a polishing layer, the fluid passages of the tubular extending along the communication with and the processing surface on the working surface through the pores of the polishing layer is formed the polishing, abrasive grains, a porous material having a binder and a pore A grinding wheel base formed integrally with the layer, and the surface to be machined and the machining by supplying pressurized fluid or discharging negative pressure fluid from a supply / discharge port formed in the grinding wheel base and communicating with the fluid passage It is characterized in that a fluid flow is generated between the surfaces.

  The grindstone of the present invention is characterized in that the polishing layer has a disk shape with a flat processed surface, and the grindstone base formed integrally with the polishing layer has a disk shape.

  The grindstone of the present invention supplies a polishing liquid having loose abrasive grains, a slurry having a chemical abrasive, or a mixture thereof between the workpiece and the processing surface via the fluid passage and pores. Features.

  The grindstone of the present invention is characterized in that the polishing layer is formed by a porous body having an open pore structure in which pores communicate with each other, and the grindstone base is formed by a porous body having a closed pore structure in which pores are closed.

  The grindstone of the present invention is characterized in that a closed pore body layer made of a porous body having a closed pore structure in which pores are closed is formed on the grindstone outer surface other than the processed surface.

  The grindstone of the present invention is characterized in that the abrasive grains are any one of diamond and CBN or a mixture thereof.

  According to the present invention, the fluid flow path is formed inside the grindstone, and the processing surface of the grindstone and the fluid flow path are communicated via the pores of the porous body constituting the grindstone. Even when a pressurized fluid is supplied, it is possible to prevent a great back pressure from being applied to the grindstone in a direction away from the grindstone holder. Thus, even if a fluid such as a slurry having a chemical abrasive is supplied under pressure to the fluid flow path, the grindstone will not be deformed so as to float from the grindstone holder. Moreover, since the fluid flow path is formed inside the integrally structured grindstone, even if the fluid is pressurized and supplied to the fluid flow path, the grindstone itself does not deform. Thereby, the deformation | transformation of the process surface of a grindstone is prevented and a highly accurate grinding | polishing process can be performed.

  Even if pressurized fluid is supplied, the grinding wheel is prevented from being deformed, so that the portion of the polishing layer of a predetermined thickness portion can be made thinner from the machining surface without increasing the pressure of pressurized fluid or negative pressure fluid. The fluid can be reliably permeated into the polishing layer through the pores.

  In order to prevent the pressurized fluid from flowing out from the outer surface of the grindstone other than the processed surface and the inflow of negative pressure fluid by flowing the pressurized fluid out of the processed surface of the grindstone and flowing in the negative pressure fluid from the processed surface, The grindstone base may be a porous body having a closed pore structure, and the outer surface other than the processed surface may be sealed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a grindstone according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a state where the grindstone shown in FIG. 1 is attached to a grindstone holder, and FIG. 4 is a partially enlarged sectional view, and FIG. 4 is a sectional view of the grindstone in the direction along line 4-4 in FIG.

  The grindstone 10 shown in FIG. 1 has a disc shape, that is, a disk shape as a whole, and has one end surface as a processing surface 11 and the other end surface as a base end surface 12. As shown in FIG. 2, the grindstone 10 is attached to the grindstone holder 20 so that the base end surface 12 is abutted against the grindstone holder 20, and is rotated by the grindstone holder 20. The grindstone 10 is attached to the grindstone holder 20 by a bolt 14 that passes through an attachment hole 13 formed on the outer periphery of the grindstone 10 and is screwed to the grindstone holder 20.

  The grindstone 10 is formed of abrasive grains and a binder that connects the abrasive grains, and is a porous body having fine pores formed therein.

  As shown in FIG. 3, the grindstone 10 has a polishing layer 15 at a portion having a predetermined thickness t from the processed surface 11, and a lower portion of the grindstone base 16 in the drawing is a grindstone base 16. Is T. As shown in FIG. 4, a plurality of fluid flow paths 17 are formed concentrically on the grindstone base 16, and in order to communicate the fluid flow paths 17 with each other, the fluid flow paths 17 are based on the thickness direction. A plurality of fluid flow paths 18 are formed radially by shifting toward the end face 12 side. Further, a supply / discharge port 19 communicating with each fluid flow path 18 is formed to open to the outside in the radial center of the grindstone base 16. When the grindstone 10 is attached to the grindstone holder 20, it is formed in the grindstone holder 20. The supply / discharge port 19 faces and communicates with the fluid flow path 21. Accordingly, each fluid channel 17 communicates with the fluid channel 21 via the fluid channel 18 and the supply / discharge port 19.

  The portion of the polishing layer 15 having the thickness t and the portion of the grinding wheel base 16 having the thickness t1 in which the fluid flow path 17 is formed are porous bodies having an open pore structure in which pores communicate with each other. The part is a porous body having a closed pore structure in which the pores are closed. The porosity of the porous body having an open pore structure is 20% or less, and the porosity of the porous body having an open pore structure is 20 to 60%. Thus, since the base end surface 12 side of the grindstone base portion 16 has a closed pore structure, when a pressurized fluid such as a polishing liquid is supplied from the fluid channel 21, the outer peripheral surface of the grindstone base portion 16 having the closed pore structure is formed. The pressurized fluid passes through the polishing layer 15 having the open pore structure without leaking the pressurized fluid, and the pressurized fluid is supplied to the processing surface 11. On the other hand, when a negative pressure supply source is communicated with the fluid flow path 21, an external fluid does not enter from the outer peripheral surface of the grindstone base 16, and the polishing liquid supplied to the processing surface 11 is a polishing layer 15 having an open pore structure. And is discharged from the supply / discharge port 19. However, the entire grindstone 10 is formed of a porous body having an open pore structure, and the outer surface other than the processing surface 11, that is, the base end surface 12 and the outer peripheral surface of the grindstone 10 are sealed, and fluid leaks from these surfaces. Inflow may be prevented.

  As shown in FIG. 2, the grindstone 10 is attached to the grindstone rotating shaft 22 of the polishing apparatus via the grindstone holder 20, and the grindstone 10 holds the grindstone holder 20 by a motor (not shown) that drives the grindstone rotating shaft 22. It is rotationally driven through. A fluid guide channel 23 formed in the grindstone rotating shaft 22 is connected to a vacuum pump 25 via a rotary joint 24, and a channel opening / closing valve is connected to the fluid guide channel 26 a connecting the vacuum pump 25 and the rotary joint 24. 27a and a pressure regulating valve 28a are attached. Therefore, when the vacuum pump 25 is operated with the flow path opening / closing valve 27a opened, the pores of the polishing layer 15 communicate with the vacuum pump 25 via the fluid guide flow path 23 and are lower than the atmospheric pressure. A vacuum state, that is, a negative pressure state occurs, and ambient air or liquid flows into the pores from the outside to the processed surface 11 of the grindstone 10.

  A pressure pump 29 is connected to the rotary joint 24, and a channel opening / closing valve 27 b and a pressure adjusting valve 28 b are attached to the fluid guide channel 26 b connecting the pressure pump 29 and the rotary joint 24. The pressurizing pump 29 pressurizes and discharges a liquid such as a polishing liquid contained in the container 30, and when the pressurizing pump 29 is operated with the flow path opening / closing valve 27 b opened, the liquid is guided to the fluid. It enters the pores of the polishing layer 15 through the flow path 23 and flows out of the processed surface 11.

  Above the grindstone rotating shaft 22 is provided a work rotating shaft 32 to which a vacuum chuck 31 for supporting and rotating a workpiece W such as a silicon wafer is mounted. The workpiece rotating shaft 32 is movable in the horizontal direction along the processing surface 11 of the grindstone 10 and is also movable in the vertical direction. The workpiece W supported by the vacuum chuck 31 is directed toward the grindstone 10. Can be moved closer and away. Furthermore, a pressing force can be applied to the workpiece W by the dead weight of the workpiece rotating shaft 32 and the vacuum chuck 31 while the workpiece W is in contact with the grindstone 10. In addition to the pressing force due to its own weight, a pressing force may be applied to the workpiece W by applying a thrust to the workpiece rotating shaft 32 by a pneumatic cylinder or the like.

  The vacuum chuck 31 has a chuck plate 34 in which a plurality of intake holes 33 are formed, and a vacuum channel 35 communicating with each of the intake holes 33 is formed in the work rotation shaft 32. The vacuum flow path 35 is connected to a vacuum pump 37 via a rotary joint 36, and a flow path opening / closing valve 39 is attached to a vacuum supply path 38 that connects the vacuum pump 37 and the rotary joint 36. Therefore, when the vacuum pump 37 is operated to bring the vacuum flow path 35 to a pressure lower than the atmospheric pressure, external air flows into the intake hole 33 and the workpiece W is vacuum-adsorbed and held by the vacuum chuck 31. .

  As shown in FIG. 4, the respective fluid flow paths 17 are formed at equal pitches in the radial direction, and are distributed in a plane along the processing surface 11. When the pressurized fluid is supplied, the pressurized fluid flows out from the entire processing surface 11, and a fluid flow such as a polishing liquid is generated between the processing surface of the workpiece W and the processing surface 11 of the grindstone 10. . On the other hand, when a negative pressure fluid is supplied from the supply / discharge port 19, an external fluid enters the polishing layer 15 from the entire processing surface 11, and the processing surface of the workpiece W and the processing surface 11 of the grindstone 10 are in contact with each other. In the meantime, a flow of fluid such as external air or polishing liquid is generated. In the case shown in FIG. 2, the outer diameter of the polishing layer 15 is about 300 mm, and the pitch in the radial direction of the fluid flow path 17 is about 15 mm.

  FIG. 5 is a cross-sectional view showing a grindstone 10 according to another embodiment of the present invention, and FIG. 5 shows a portion of a fluid flow path 17 formed in the grindstone 10 as in FIG. The fluid flow path 17 formed in the grindstone 10 shown in FIG. 5 is continuous in a spiral shape, and the fluid flow paths 17 are dispersed in a plane along the processing surface 11 and formed at a predetermined pitch in the radial direction. . Also in this case, as in the case shown in FIG. 4, a plurality of fluid flow paths 18 are formed in the grindstone 10 so as to communicate with the fluid flow paths 17 in the radial direction. However, since the fluid flow path 17 shown in FIG. 5 is formed by a continuous flow path that is spirally connected, the fluid supply port 17 may be directly connected to the central portion of the fluid flow path 17 so that the fluid flow The pressurized fluid can be guided to the entire flow path 17.

  6A is a cross-sectional view showing a grindstone 10 according to another embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along line 6B-6B in FIG. 6A. (A) shows the part of the fluid flow path 17 formed in the grindstone 10 like FIG. The fluid flow path 17 formed in the grindstone 10 shown in FIG. 6 has a lattice shape, and the total area of the fluid flow path 17 in the direction along the processing surface 11 is larger than that shown in FIGS. 4 and 5. At the same time, the dispersion density in the direction along the processed surface 11 is high. Since the lattice-like fluid flow path 17 communicates as a whole, as shown in FIG. 6 (B), the supply / discharge port 19 is directly communicated with the central portion of the fluid flow path 17 so that the grindstone 10 as a whole. The thickness dimension can be made thinner than the grindstone 10 shown in FIGS. However, the radial fluid flow path 18 may be formed in the grindstone 10 in the same manner as described above.

  As shown in FIGS. 1 to 6, fluid flow paths 17 and 18 are provided inside the integrally formed grindstone 10, and the polishing liquid pressurized by the pressure pump 29 is fluidized from the supply / discharge port 19. When supplied into the flow paths 17 and 18, a back pressure corresponding to the product of the area of the supply / discharge port 19 and the fluid pressure is only applied to the grindstone 10, and the fluid pressure is applied to almost the entire base end surface 12 of the grindstone 10. Compared to the case, the back pressure acting in the direction of separating the grindstone 10 from the grindstone holder 20 is slight. Therefore, the grindstone 10 does not deform in the direction of lifting from the grindstone holder 20. Further, even if the pressure of the pressurized fluid is applied to the fluid flow paths 17 and 18, the fluid flow paths 17 and 18 are formed in the grindstone 10 that is integrated and integrated systematically. It is possible to prevent cracks from being generated or deformed.

  As the polishing process using the grindstone 10, the polishing process of the workpiece W in which the polishing liquid having free abrasive grains is pressurized by the pressure pump 29 and flows out from the processing surface 11 through the fluid flow path 17, Further, the present invention can be applied to a polishing process, that is, a CMP process in which a slurry having a chemical abrasive is allowed to flow out from the processed surface 11 on the surface of the wafer before the circuit pattern is formed or the wafer on which the circuit pattern is formed. In such a polishing process, since a polishing liquid or the like is supplied from the processing surface 11 between the grindstone 10 and the workpiece W, the polishing liquid is reliably supplied to the entire processing surface of the workpiece W. can do. In addition, since the grindstone 10 has a higher hardness of the processed surface 11 than a polishing pad made of urethane or the like as in a normal CMP process, the grindstone 10 is polished with high flatness without causing waviness or the like on the surface of the wafer. Processing can be performed, and further, by adjusting the pressure between the processing surface 11 and the workpiece W, the polishing processing time and the polishing amount can be easily set.

  In order to manufacture the grindstone 10 in which the fluid flow paths 17 and 18 are formed, a mixture of abrasive grains, a binder, and an auxiliary agent is injected into a mold. On the other hand, a core made of a disappearing material that disappears when heat is applied, such as a disappearing resin, is manufactured in the shape of the fluid flow paths 17 and 18 in advance, and the mixture is injected into the mold when injected into the mold. Insert the core. By heating the grinding wheel material formed in the shape corresponding to the grinding wheel 10 in the firing furnace in this manner, the core disappears and the abrasive grains are connected by the binder, and the fluid flow path has pores inside. A grindstone 10 made of a porous body on which 17 and 18 are formed is integrally manufactured. Although the porosity of the grindstone 10 decreases as the amount of the auxiliary agent is increased, the porosity can be adjusted not only by the amount of the auxiliary agent but also by the firing temperature or the like.

  Therefore, when the grindstone 10 is formed by the portion of the polishing layer 15 and the grindstone base 16 as described above, for example, by making the amount of the auxiliary agent different between the polishing layer 15 and the grindstone base 16, The portion of the grindstone base 16 where the fluid flow path 17 is formed (the portion of thickness t + t1) is a porous body having an open pore structure, and the portion closer to the base end face 12 than this portion is a porous body having a closed pore structure. can do.

  However, the part having the polishing layer 15 and the other part may be molded separately and fired in a state where they are abutted, and after each part is separately molded and fired, both are made of glass adhesive. The glass adhesive layer may be melted and bonded under a state of being butted through the layers. In any case, since the entire grindstone 10 is formed integrally with the structure constituting it, even if a pressurized polishing liquid is supplied into the fluid flow paths 17 and 18, The grindstone 10 can be polished with high accuracy without being deformed or causing cracks. In addition, as above-mentioned, the grindstone 10 whole is formed with the porous body of an open-pore structure, and the outer surface other than the process surface 11 in the grindstone 10, ie, a base end surface 12, and an outer peripheral surface is sealed, and from these surfaces The fluid may be prevented from leaking out and flowing in.

As the abrasive grains constituting the grindstone 10, diamond, that is, diamond abrasive grains are used, and the average particle diameter is 0.1 to 300 μm. However, instead of diamond, cubic boron nitride (CBN) abrasive grains or CBN may be used, a mixture of diamond and CBN may be used, and silicon carbide SiC or GC. , Mullite (3Al ₂ O ₃ -2SiO ₂ ), or molten alumina Al ₂ O _3, that is, WA alone or a mixture thereof may be used. Vitrified bonds are used as the binding material constituting the grindstone 10, but various bonding materials such as resinoid bonds, metal bonds, and electrodeposition bonds can be used as the respective binding materials in addition to vitrified bonds. .

  7A is a side view showing the overall configuration of the polishing apparatus using the grindstone 10, FIG. 7B is a front view of FIG. 7A, and FIG. 8 is 8 in FIG. 7B. It is an expanded sectional view which follows -8 line.

  This polishing apparatus has a base 41 in which the grindstone rotating shaft 22 shown in FIG. 2 is rotatably incorporated, and a polishing head 42 provided on the base 41, and two polishing heads 42 are provided. The workpiece rotation shafts 32 are rotatably provided. Therefore, the illustrated polishing apparatus can polish two workpieces W at the same time.

  A pulley 43 is fixed to the grindstone rotating shaft 22 as shown in FIG. 8, and a belt 46 is interposed between the pulley 45 and the pulley 43 of the motor 44 fixed to the base 41 as shown in FIG. The grindstone rotating shaft 22 is rotationally driven by a motor 44. A hose 47 constituting the fluid guide channel 23 is connected to the rotary joint 24 attached to the grindstone rotating shaft 22, and the rotary pump 24 and the vacuum pump 25 shown in FIG. Either one or both of the pressure pumps 29 are connected.

  The polishing head 42 is provided with a slide base 49 that slides along a guide rail 48 fixed in the horizontal direction to the polishing head 42, and each work rotation shaft 32 is movable in the vertical direction on the slide base 49. And it is rotatably provided. A spline 51 is provided on the upper end side of each work rotation shaft 32, and a pulley 52 meshing with the spline 51 is rotatably incorporated in a slide base 49, and a motor 53 fixed to the pulley 52 and the slide base 49. A belt 55 is stretched between the pulley 54 and the work rotation shaft 32 by a motor 53. The work rotation shaft 32 is incorporated in a sleeve 55 that is mounted on the slide base 49 so as to be movable up and down. The work rotation shaft 32 is moved up and down via the sleeve 55 and moved toward and away from the grindstone 10. For this purpose, the piston rod 57 of the pneumatic cylinder 56 attached to the slide base 49 is connected to the sleeve 55. A rotary joint 36 is attached to the end of the work rotation shaft 32, and this rotary joint 36 is connected to a vacuum pump 37 as shown in FIG. FIG. 8 shows one of the two workpiece rotating shafts 32 provided on the polishing head 42 as shown in FIG. 7, both of which have the same structure.

  In order to polish the surface of a disk-shaped workpiece W such as a silicon wafer by the polishing apparatus shown in FIGS. 7 and 8, the workpiece W is held in the respective vacuum chucks 31. Then, the work rotation shaft 32 is moved toward the grindstone 10 by the pneumatic cylinder 56. The workpiece W is brought into contact with the processing surface 11 of the grindstone 10 while the workpiece 53 is rotated by the motor 53 and the grindstone rotation shaft 22 is rotated by the motor 44. The grindstone 10 and the workpiece W are slid relative to each other by the motors 44 and 53. When the vacuum pump 25 is driven in this state, the machining surface 11 and the workpiece surface of the workpiece W In between, a flow of negative pressure air is generated through the pores of the grindstone 10, and between these, a negative pressure state occurs and a pressure lower than the atmospheric pressure is generated. On the other hand, when air or liquid is supplied from the pressurizing pump 29 between the processing surface 11 and the workpiece W, a pressure higher than the atmospheric pressure is generated between them. Each pressure is adjusted by pressure regulating valves 28a and 28b. In this way, by adjusting the pressure in the gap and changing the thickness thereof, the number of abrasive grains contacting the work surface can be changed, and the polishing amount and the finishing accuracy of the work surface can be adjusted.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. For example, a grindstone 10 shown in the figure is a disc-shaped grindstone for polishing a flat surface provided with a flat work surface 11 on an end surface, and a grindstone is formed in a cup shape or a ring shape instead of a disc shape. Surface polishing may be performed using the surface as the processing surface. The present invention is also applied to a grinding wheel for processing a cylindrical outer peripheral surface of a workpiece and an inner surface polishing process for processing a cylindrical inner peripheral surface of a workpiece. Alternatively, a fluid flow path may be formed.

It is a perspective view which shows the grindstone which is one embodiment of this invention. It is sectional drawing which shows the state in which the grindstone shown in FIG. 1 was attached to the grindstone holder. It is a partially expanded sectional view of FIG. It is sectional drawing of the grindstone of the direction in alignment with line 4-4 in FIG. It is sectional drawing which shows the grindstone which is other embodiment of this invention. (A) is sectional drawing which shows the grindstone which is other embodiment of this invention, (B) is sectional drawing which follows the 6B-6B line | wire in (A). (A) is a side view which shows the whole structure of the grinding | polishing apparatus using a grindstone, (B) is a front view of (A). It is an expanded sectional view which follows the 8-8 line in FIG.7 (B).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Grinding wheel 11 Processing surface 12 Base end surface 15 Polishing layer 16 Grinding wheel base parts 17 and 18 Fluid flow path 19 Supply / discharge port 20 Grinding wheel holder 22 Grinding wheel rotation shaft 25 Vacuum pump 29 Pressure pump 31 Vacuum chuck W Workpiece

Claims (6)

A grindstone for polishing a workpiece surface of a workpiece,
A polishing layer provided with a processing surface that is formed of a porous body having abrasive grains, a binder, and pores and that polishes the processing surface;
The communication to and fluid passage of the tubular extending along the working surface to the working surface through the pores of the polishing layer is formed, abrasive grains, formed integrally with the abrasive layer of a porous material having a binder and a pore And a grindstone base to be
A fluid flow is generated between the processing surface and the processing surface by supplying pressurized fluid from a supply / exhaust port formed on the grindstone base or communicating with the fluid passage or discharging negative pressure fluid. A whetstone characterized by that.   2. The grindstone according to claim 1, wherein the polishing layer has a disc shape with a flat processed surface, and the grindstone base formed integrally with the polishing layer has a disc shape.   3. The grindstone according to claim 1, wherein a polishing liquid having loose abrasive grains, a slurry having a chemical abrasive, or a mixture thereof is interposed between the workpiece and the processing surface through the fluid passage and pores. A grindstone characterized by being supplied.   The grindstone according to any one of claims 1 to 3, wherein the polishing layer is formed by a porous body having an open pore structure in which pores communicate with each other, and the grindstone is formed by a porous body having a closed pore structure in which pores are closed. A grindstone characterized by forming a base.   The grindstone according to any one of claims 1 to 3, wherein a closed pore body layer made of a porous body having a closed pore structure in which pores are closed is formed on a grindstone outer surface other than the processed surface. A whetstone characterized by that. In the grindstone according to any one of claims 1 to 5,
The grindstone according to claim 1, wherein the fluid passage is formed to have any one of a concentric shape, a spiral shape, and a lattice shape .

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