US20240066665A1 - Grindstone - Google Patents
Grindstone Download PDFInfo
- Publication number
- US20240066665A1 US20240066665A1 US18/446,658 US202318446658A US2024066665A1 US 20240066665 A1 US20240066665 A1 US 20240066665A1 US 202318446658 A US202318446658 A US 202318446658A US 2024066665 A1 US2024066665 A1 US 2024066665A1
- Authority
- US
- United States
- Prior art keywords
- filler
- binder
- grinding
- workpiece
- grindstone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
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- 239000011230 binding agent Substances 0.000 claims abstract description 49
- 239000006061 abrasive grain Substances 0.000 claims abstract description 22
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- 239000002245 particle Substances 0.000 claims description 27
- 239000000919 ceramic Substances 0.000 claims description 7
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- 239000000463 material Substances 0.000 abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 18
- 238000012545 processing Methods 0.000 description 18
- 239000007788 liquid Substances 0.000 description 9
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- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
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- 238000000748 compression moulding Methods 0.000 description 1
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/14—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic ceramic, i.e. vitrified bondings
- B24D3/18—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic ceramic, i.e. vitrified bondings for porous or cellular structure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
- B24D7/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/34—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties
- B24D3/342—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties incorporated in the bonding agent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/20—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground
- B24B7/22—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain
- B24B7/228—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain for grinding thin, brittle parts, e.g. semiconductors, wafers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/14—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic ceramic, i.e. vitrified bondings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/20—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially organic
- B24D3/28—Resins or natural or synthetic macromolecular compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/20—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially organic
- B24D3/28—Resins or natural or synthetic macromolecular compounds
- B24D3/32—Resins or natural or synthetic macromolecular compounds for porous or cellular structure
Definitions
- the present invention relates to a grindstone used for processing a workpiece.
- Device chips including devices are manufactured by dividing and individualizing a wafer formed with a plurality of devices.
- a package substrate is formed by mounting a plurality of device chips on a predetermined substrate and covering the device chips with a resin layer (molding resin) to seal the device chips.
- a resin layer molding resin
- package devices including a plurality of packaged device chips are manufactured.
- the device chips and the package devices are incorporated into various electronic apparatuses such as mobile phones and personal computers.
- the grinding apparatus includes a chuck table for holding a workpiece and a grinding unit for grinding the workpiece.
- the grinding unit includes a spindle, and an annular grinding wheel including a plurality of grindstones is mounted to a tip end part of the spindle.
- the workpiece is held by the chuck table, and, while the chuck table and the grinding wheel are rotated, grinding surfaces of the grindstones are brought into contact with the workpiece to grind the workpiece (see Japanese Patent Laid-open No. 2000-288881).
- the grindstones used for grinding the workpiece are formed by fixing abrasive grains with a binder (bond material).
- a binder bond material
- a mixture containing diamond abrasive grains and a vitrified bond material is kneaded and granulated, followed by compression molding and firing, whereby a vitrified bond grindstone is obtained (see Japanese Patent Laid-open No. 2006-1007).
- the binder of the grindstone contains a filler (aggregate) for reinforcing the binder.
- a filler typically, ceramic particles having an angular random shape (angular shape) are used. Addition of the filler to the binder enhances mechanical strength of the binder and prolongs the useful life of the binder. As a result, the cost of the grindstone is lowered, and lowering in processing efficiency attendant on replacing work of the grindstone is restrained. In addition, it has been confirmed that use of a filler of a larger size further enhances the strength of the binder.
- the present invention has been made in consideration of such a problem, and it is an object of the invention to provide a grindstone which is high in strength and is capable of restraining occurrence of defective processing.
- a grindstone including abrasive grains and a binder for fixing the abrasive grains, in which the binder contains a spherical filler for reinforcing the binder.
- the average particle diameter of the filler is greater than the average particle diameter of the abrasive grains.
- the filler is ceramic particles, and the ratio of a short axis to a long axis of the ceramic particles is not less than 0.7.
- the content of the filler in the binder is 5 to 90 wt %.
- the binder is a vitrified bond or a resin bond.
- the binder for fixing the abrasive grains contains the spherical filler.
- FIG. 1 is a perspective view depicting a grinding apparatus
- FIG. 2 is a perspective view depicting a grinding wheel
- FIG. 3 is a sectional view depicting a part of a grindstone
- FIG. 4 is a graph depicting the results of measurement of strengths of grindstones.
- FIG. 1 is a perspective view depicting a grinding apparatus 2 for grinding a workpiece 11 .
- an X-axis direction (a first horizontal direction, a front-rear direction) and a Y-axis direction (a second horizontal direction, a left-right direction) are mutually perpendicular directions.
- a Z-axis direction (a height direction, a vertical direction, an up-down direction) is a direction perpendicular to both the X-axis direction and the Y-axis direction.
- the workpiece 11 is a disk-shaped wafer formed of a semiconductor material such as single crystal silicon, and has a front surface (a first surface) 11 a and a back surface (a second surface) 11 b which are substantially parallel to each other.
- the workpiece 11 is partitioned into a plurality of rectangular regions by a plurality of streets (scheduled division lines) arranged in a grid pattern in such a manner as to mutually intersect.
- streets such devices (not illustrated) as integrated circuits (ICs), large scale integration (LSI) circuits, light emitting diodes (LEDs), and micro electro mechanical systems (MEMS) devices are formed respectively on the front surface 11 a side of the plurality of regions partitioned by the streets.
- ICs integrated circuits
- LSI large scale integration
- LEDs light emitting diodes
- MEMS micro electro mechanical systems
- a plurality of device chips respectively provided with the devices are manufactured.
- various processing apparatuses such as a cutting apparatus for cutting the workpiece 11 by an annular cutting blade and a laser processing apparatus for processing the workpiece 11 by applying a laser beam.
- a cutting apparatus for cutting the workpiece 11 by an annular cutting blade and a laser processing apparatus for processing the workpiece 11 by applying a laser beam.
- the back surface 11 b side of the workpiece 11 is preliminarily ground by the grinding apparatus 2 to thin the workpiece 11 prior to the division of the workpiece 11 , thinned device chips are obtained.
- the kind, material, size, shape, structure, and the like of the workpiece 11 are not limited to any particular ones.
- the workpiece 11 may be a wafer (substrate) formed of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramic, resin, metal, or the like.
- the kinds, number, shapes, structures, sizes, layout, and the like of the devices are not limited to any particular ones, and the workpiece 11 may not be formed with the devices.
- the grinding apparatus 2 includes a base 4 for supporting or accommodating each of constituent elements constituting the grinding apparatus 2 .
- a rectangular opening 4 a is formed such that the longitudinal direction thereof extends along the X-axis direction.
- a rectangular parallelepiped support structure 6 is provided along the Z-axis direction.
- a chuck table (a holding table) 8 for holding the workpiece 11 On the inside of the opening 4 a , a chuck table (a holding table) 8 for holding the workpiece 11 is provided.
- An upper surface of the chuck table 8 is a flat surface substantially parallel to a horizontal plane (XY plane), and constitutes a holding surface 8 a for holding the workpiece 11 .
- the holding surface 8 a is connected to a suction source (not illustrated) such as an ejector through a flow channel (not illustrated) formed inside the chuck table 8 , a valve (not illustrated), and the like.
- An X-axis moving unit 10 for moving the chuck table 8 along the X-axis direction is connected to the chuck table 8 .
- the X-axis moving unit 10 is, for example, a ball screw type moving mechanism, and is provided inside the opening 4 a .
- the X-axis moving unit 10 includes an X-axis ball screw (not illustrated) disposed along the X-axis direction and an X-axis pulse motor (not illustrated) for rotating the X-axis ball screw.
- the X-axis moving unit 10 includes a flat plate-shaped table cover 12 provided in such a manner as to surround the chuck table 8 .
- bellows-like dustproof and droplet-proof covers 14 capable of contracting and extending in the X-axis direction are provided.
- the table cover 12 and the dustproof and droplet-proof covers 14 are provided in such a manner as to cover the constituent elements (the X-axis ball screw, the X-axis pulse motor, and the like) of the X-axis moving unit 10 accommodated inside the opening 4 a .
- the chuck table 8 is moved in the X-axis direction together with the table cover 12 , and is positioned at a front end part (conveying position) or a rear end part (grinding position) of the opening 4 a .
- a rotational drive source such as a motor for rotating the chuck table 8 around a rotational axis substantially parallel to the Z-axis direction is connected to the chuck table 8 .
- a Z-axis moving unit 16 On a front surface side of the support structure 6 , a Z-axis moving unit 16 is provided.
- the Z-axis moving unit 16 includes a pair of Z-axis guide rails 18 disposed along the Z-axis direction.
- a flat plate-shaped Z-axis moving plate 20 is mounted to the pair of Z-axis guide rails 18 in such a manner as to be slidable along the Z-axis guide rails 18 .
- a nut section On a back surface side (a rear surface side) of the Z-axis moving plate 20 , a nut section (not illustrated) is provided. The nut section is in screw engagement with a Z-axis ball screw 22 disposed along the Z-axis direction between the pair of Z-axis guide rails 18 .
- a Z-axis pulse motor 24 for rotating the Z-axis ball screw 22 is connected to an end part of the Z-axis ball screw 22 .
- the Z-axis moving plate 20 is moved (lifted or lowered) in the Z-axis direction along the Z-axis guide rails 18 .
- a support member 26 is fixed to a front surface side of the Z-axis moving plate 20 .
- the support member 26 supports a grinding unit 28 for grinding the workpiece 11 .
- the grinding unit 28 includes a cylindrical housing 30 supported by the support member 26 .
- a cylindrical spindle 32 disposed along the Z-axis direction is accommodated in the housing 30 .
- a tip end part (a lower end part) of the spindle 32 projects downward from a lower surface of the housing 30 .
- a rotational drive source (not illustrated) such as a motor is connected to a base end part (an upper end part) of the spindle 32 .
- a disk-shaped wheel mount 34 made of metal or the like is fixed to the tip end part of the spindle 32 .
- An annular grinding wheel 36 for grinding the workpiece 11 is detachably mounted to a lower surface side of the wheel mount 34 .
- the grinding wheel 36 includes an annular wheel base 38 and a plurality of grindstones 40 fixed to the wheel base 38 .
- the grinding wheel 36 is rotated around a rotational axis substantially parallel to the Z-axis direction by motive power transmitted from the rotational drive source through the spindle 32 and the wheel mount 34 . Note that the configuration and functions of the grinding wheel 36 will be described later (see FIG. 2 ).
- the grinding apparatus 2 includes a controller (control unit, control section, control device) 42 for controlling the grinding apparatus 2 .
- the controller 42 is connected to each of constituent elements (the chuck table 8 , the X-axis moving unit 10 , the Z-axis moving unit 16 , the grinding unit 28 , etc.) of the grinding apparatus 2 .
- the controller 42 sends control signals to the constituent elements of the grinding apparatus 2 to thereby control the operation of the grinding apparatus 2 .
- the controller 42 includes a computer.
- the controller 42 includes a processing section for performing calculations and the like for the operation of the grinding apparatus 2 and a storage section for storing various kinds of information (data, a program, and the like) used for the operation of the grinding apparatus 2 .
- the processing section includes a processor such as a central processing unit (CPU).
- the storage section includes a memory such as a read only memory (ROM) and a random access memory (RAM).
- the workpiece 11 is held by the chuck table 8 .
- the workpiece 11 is disposed on the chuck table 8 such that the front surface 11 a side faces the holding surface 8 a and the back surface 11 b side is exposed to the upper side.
- a suction force (negative pressure) of the suction source is made to act on the holding surface 8 a , whereby the workpiece 11 is held under suction by the chuck table 8 .
- the chuck table 8 is moved by the X-axis moving unit 10 , and is positioned on the lower side of the grinding wheel 36 (grinding position).
- the grinding wheel 36 is lowered at a predetermined speed by the Z-axis moving unit 16 , to bring the grindstones 40 into contact with the workpiece 11 .
- the back surface 11 b side of the workpiece 11 is ground away, and the workpiece 11 is ground and thinned.
- the grinding wheel 36 is fixed to the wheel mount 34 (see FIG. 1 ) by fixing means (not illustrated) such as fastening bolts, for example. As a result, the grinding wheel 36 is mounted to the tip end part of the spindle 32 through the wheel mount 34 .
- FIG. 2 is a perspective view depicting the grinding wheel 36 including the wheel base 38 and the plurality of grindstones 40 .
- the wheel base 38 is formed of such metal as an aluminum alloy, and is formed in an annular shape substantially equal in diameter to the wheel mount 34 (see FIG. 1 ).
- the wheel base 38 includes a first surface 38 a and a second surface 38 b which are substantially parallel to each other.
- the first surface 38 a corresponds to a fixed end face fixed to the wheel mount 34 (see FIG. 1 )
- the second surface 38 b corresponds to a free end face which is not fixed to the wheel mount 34 .
- the wheel base 38 is provided in a central part thereof with an opening 38 c penetrating the wheel base 38 in the thickness direction from the first surface 38 a to the second surface 38 b .
- the opening 38 c is formed in a frustoconical shape whose diameter increases from the first surface 38 a toward the second surface 38 b .
- an annular groove 38 d is provided on the second surface 38 b side of the wheel base 38 .
- the groove 38 d is formed concentrically with the wheel base 38 on the outer circumferential side of the wheel base 38 than the opening 38 c .
- the plurality of grindstones 40 for grinding the workpiece 11 are fixed.
- the plurality of grindstones 40 are each formed, for example, in a rectangular parallelepiped shape, and are arranged in an annular pattern at substantially equal intervals along the groove 38 d .
- the width of the grindstones 40 and the width of the groove 38 d are substantially equal, and the grindstones 40 are arranged such that the lengthwise direction (longitudinal direction) thereof is along the tangential direction (circumferential direction) of the groove 38 d .
- the grindstone 40 includes a rectangular grinding surface 40 a which is exposed to the side opposite to the wheel base 38 .
- the grinding surface 40 a is a surface that comes into contact with the workpiece 11 at the time of grinding, and the workpiece 11 is ground by the grinding surface 40 a.
- the wheel base 38 includes a plurality of grinding liquid supply passages 38 e penetrating the wheel base 38 from the first surface 38 a to the second surface 38 b .
- One end side of the grinding liquid supply passage 38 e is opened in the first surface 38 a
- the other end side of the grinding liquid supply passage 38 e is opened in that region of the second surface 38 b which is located between the opening 38 c and the groove 38 d .
- the openings of the plurality of grinding liquid supply passages 38 e exposed in the second surface 38 b are arranged in an annular pattern at substantially equal intervals along the circumferential direction of the wheel base 38 .
- the grinding wheel 36 is mounted to the wheel mount 34 which is fixed to the tip end part of the spindle 32 .
- the grinding wheel 36 is rotated around a rotational axis which is substantially parallel to the Z-axis direction.
- the plurality of grindstones 40 are each rotated (slewed) along an annular rotational route centered on a rotational axis of the grinding wheel 36 .
- the workpiece 11 is ground.
- liquid such as pure water is supplied to one end side of the grinding liquid supply passage 38 e (the first surface 38 a side of the wheel base 38 ), and the grinding liquid is supplied from the other end side of the grinding liquid supply passage 38 e to the workpiece 11 and the plurality of grindstones 40 .
- the workpiece 11 and the grindstones 40 are cooled, and swarf (grinding swarf) generated by grinding of the workpiece 11 is washed away.
- FIG. 3 is a sectional view depicting a part of the grindstone 40 .
- the grindstone 40 includes abrasive grains 50 formed of diamond, cubic boron nitride (cBN), or the like and a binder (bonding material) 52 for fixing the abrasive grains 50 .
- the binder 52 there can be used a vitreous vitrified bond containing SiO 2 or the like as a main constituent, a resin bond containing resin as a main constituent, or the like.
- a number of pores are formed inside the binder 52 . It is to be noted, however, that the material and grain diameter of the abrasive grains 50 and the material of the binder 52 are not limited to any kind.
- the binder 52 contains a filler (aggregate) 54 for reinforcing the binder 52 .
- a filler (aggregate) 54 for reinforcing the binder 52 .
- the filler 54 contained in the binder 52 , mechanical strength of the binder 52 is enhanced, and consumption of the grindstones 40 is suppressed.
- a spherical filler 54 is contained in the binder 52 .
- the filler 54 does not have an angular random shape (angular shape), and is particles (powder material) having a true spherical shape or a shape resembling a true sphere.
- the ratio of a short axis a to a long axis b (aspect ratio a/b) of the filler 54 is not less than 0.7, preferably not less than 0.8, and more preferably not less than 0.9.
- the short axis a of the filler 54 passes through the center (center of gravity) of the filler 54 and corresponds to the length of a shortest straight line connecting two points on the surface of the filler 54 .
- the long axis b of the filler 54 passes through the center (center of gravity) of the filler 54 and corresponds to the length of a longest straight line connecting two points on the surface of the filler 54 .
- the short axis a corresponds to a short diameter of the filler 54
- the long axis b corresponds to a long diameter of the filler 54
- the circularity of the filler 54 is, for example, not less than 0.95, preferably not less than 0.96, and more preferably not less than 0.97.
- the convexity of the filler 54 is, for example, not less than 0.97, preferably not less than 0.98, and more preferably not less than 0.99, and the solidity of the filler 54 is, for example, not less than 0.94, preferably not less than 0.95, and more preferably not less than 0.96.
- spherical ceramic particles formed of aluminum oxide (alumina, Al 2 O 3 ), silicon dioxide (silica, SiO 2 ), or the like are used as the filler 54 .
- As a commercial product which can be used as the filler 54 there may be mentioned true spherical fine particles (trade name: ADMAFINE (registered trademark)) made by ADMATECHS COMPANY LIMITED.
- the amount of the filler 54 contained in the binder 52 is adjusted according to the strength of the binder 52 required.
- the content of the filler 54 in the binder 52 can be set to be 5 to 90 wt %, and preferably 60 to 80 wt %. This content corresponds to the ratio of the mass of the filler 54 based on the mass of the binder 52 in which the filler 54 is contained (the total of the mass of the binder 52 and the mass of the filler 54 ).
- the strength of the binder 52 is high as compared to the case where a filler of an angular shape is used (see FIG. 4 ).
- the strength of the binder 52 is higher as the size of the filler 54 is greater (see FIG. 4 ).
- the average particle diameter of the filler 54 be greater than the average particle diameter of the abrasive grains 50 .
- the average particle diameter of the filler 54 is 1.1 to 20 times the average particle diameter of the abrasive grains 50 .
- the particle diameters of the abrasive grains 50 and the filler 54 can be measured, for example, by a laser diffraction method.
- the filler 54 has an angular shape
- the sharp angular parts of the filler 54 largely project from the binder 52 to be liable to collide against the workpiece 11 , and defective processing may occur.
- the spherical filler 54 is used as in the present embodiment, even if the filler 54 projects from the binder 52 , only a smooth surface (curved surface) of the filler 54 would make contact with the workpiece 11 .
- the average particle diameter of the filler 54 is greater than the average particle diameter of the abrasive grains 50 , damaging of the workpiece 11 by the filler 54 is not liable to occur, and defective processing is restrained.
- the binder 52 for fixing the abrasive grains 50 contains the spherical filler 54 . As a result, it is possible to restrain occurrence of defective processing at the time of processing the workpiece 11 by the grindstones 40 , while enhancing the strength of the grindstones 40 .
- a plurality of rectangular parallelepiped grindstones (with the length of 20 mm, the width of 10 mm, and the thickness of 4 mm) containing no abrasive grains but fillers in the binder (vitrified bons) were used.
- a grindstone A containing aluminum oxide of an angular shape as the filler, a grindstone B containing spherical aluminum oxide as the filler, and a grindstone C containing spherical silicon dioxide as the filler were formed.
- two kinds of grindstones A, four kinds of grindstones B, and three kinds of grindstones C, which were different in particle diameter of the filler were prepared.
- the particle diameters of the filler (aluminum oxide of angular shape) contained in the two kinds of grindstones A were 0.5 ⁇ m and 2 ⁇ m.
- the particle diameters of the filler (spherical aluminum oxide) contained in the four kinds of grindstones B were 0.7 ⁇ m, 4.2 ⁇ m, 5 ⁇ m, and 5.4 ⁇ m.
- the particle diameters of the filler (spherical silicon dioxide) contained in the three kinds of grindstones C were 1.6 ⁇ m, 3 ⁇ m, and 5.7 ⁇ m.
- FIG. 4 is a graph depicting the measurement results of the strength of the grindstones.
- the strength of the grindstone was higher as the particle diameter of the filler was greater.
- enlargement of the filler is effective for enhancing the strength of the grindstone.
- a grindstone B having a strength of not less than 10 MPa, not less than 30 MPa, or not less than 40 MPa was obtained.
- a grindstone C having a strength of not less than 5 MPa or not less than 10 MPa was obtained.
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Abstract
A grindstone includes abrasive grains and a binder for fixing the abrasive grains, and the binder contains a spherical filler for reinforcing the bonding material.
Description
- The present invention relates to a grindstone used for processing a workpiece.
- Device chips including devices are manufactured by dividing and individualizing a wafer formed with a plurality of devices. In addition, a package substrate is formed by mounting a plurality of device chips on a predetermined substrate and covering the device chips with a resin layer (molding resin) to seal the device chips. By dividing and individualizing the package substrate, package devices including a plurality of packaged device chips are manufactured. The device chips and the package devices are incorporated into various electronic apparatuses such as mobile phones and personal computers.
- In recent years, in association with miniaturization of the electronic apparatuses, thinning of the device chips and the package devices has been demanded. In view of this, a process of grinding the wafer or the package substrate prior to division by a grinding apparatus may be conducted. The grinding apparatus includes a chuck table for holding a workpiece and a grinding unit for grinding the workpiece. The grinding unit includes a spindle, and an annular grinding wheel including a plurality of grindstones is mounted to a tip end part of the spindle. The workpiece is held by the chuck table, and, while the chuck table and the grinding wheel are rotated, grinding surfaces of the grindstones are brought into contact with the workpiece to grind the workpiece (see Japanese Patent Laid-open No. 2000-288881).
- The grindstones used for grinding the workpiece are formed by fixing abrasive grains with a binder (bond material). For example, a mixture containing diamond abrasive grains and a vitrified bond material is kneaded and granulated, followed by compression molding and firing, whereby a vitrified bond grindstone is obtained (see Japanese Patent Laid-open No. 2006-1007).
- The binder of the grindstone contains a filler (aggregate) for reinforcing the binder. As the filler, typically, ceramic particles having an angular random shape (angular shape) are used. Addition of the filler to the binder enhances mechanical strength of the binder and prolongs the useful life of the binder. As a result, the cost of the grindstone is lowered, and lowering in processing efficiency attendant on replacing work of the grindstone is restrained. In addition, it has been confirmed that use of a filler of a larger size further enhances the strength of the binder.
- However, even when a filler of an angular shape is contained in the binder of the grindstone, there is a limit in enhancing the strength of the grindstone. In addition, if the size of the filler of the angular shape is enlarged for enhancing the strength of the grindstone, sharp angular parts of the filler would largely project from the binder, and would be liable to collide against the workpiece during processing. As a result, although the contact between the abrasive grains and the workpiece should dominantly contribute to processing of the workpiece in a normal situation, the projecting angular parts of the filler would interfere with the workpiece, and may cause defective processing.
- The present invention has been made in consideration of such a problem, and it is an object of the invention to provide a grindstone which is high in strength and is capable of restraining occurrence of defective processing.
- In accordance with an aspect of the present invention, there is provided a grindstone including abrasive grains and a binder for fixing the abrasive grains, in which the binder contains a spherical filler for reinforcing the binder.
- Note that, preferably, the average particle diameter of the filler is greater than the average particle diameter of the abrasive grains. In addition, preferably, the filler is ceramic particles, and the ratio of a short axis to a long axis of the ceramic particles is not less than 0.7. Besides, preferably, the content of the filler in the binder is 5 to 90 wt %. In addition, preferably, the binder is a vitrified bond or a resin bond.
- In the grindstone according to one mode of the present invention, the binder for fixing the abrasive grains contains the spherical filler. As a result, it is possible to restrain occurrence of defective processing at the time of processing a workpiece by the grindstone, while enhancing the strength of the grindstone.
- The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing a preferred embodiment of the invention.
-
FIG. 1 is a perspective view depicting a grinding apparatus; -
FIG. 2 is a perspective view depicting a grinding wheel; -
FIG. 3 is a sectional view depicting a part of a grindstone; and -
FIG. 4 is a graph depicting the results of measurement of strengths of grindstones. - An embodiment according to one mode of the present invention will be described with reference to the attached drawings. First, a configuration example of a grinding apparatus that can grind a workpiece by use of a grinding wheel according to the present embodiment will be described.
FIG. 1 is a perspective view depicting agrinding apparatus 2 for grinding aworkpiece 11. Note that, inFIG. 1 , an X-axis direction (a first horizontal direction, a front-rear direction) and a Y-axis direction (a second horizontal direction, a left-right direction) are mutually perpendicular directions. In addition, a Z-axis direction (a height direction, a vertical direction, an up-down direction) is a direction perpendicular to both the X-axis direction and the Y-axis direction. - For example, the
workpiece 11 is a disk-shaped wafer formed of a semiconductor material such as single crystal silicon, and has a front surface (a first surface) 11 a and a back surface (a second surface) 11 b which are substantially parallel to each other. Theworkpiece 11 is partitioned into a plurality of rectangular regions by a plurality of streets (scheduled division lines) arranged in a grid pattern in such a manner as to mutually intersect. In addition, such devices (not illustrated) as integrated circuits (ICs), large scale integration (LSI) circuits, light emitting diodes (LEDs), and micro electro mechanical systems (MEMS) devices are formed respectively on thefront surface 11 a side of the plurality of regions partitioned by the streets. As a result of dividing theworkpiece 11 along the streets, a plurality of device chips respectively provided with the devices are manufactured. For division of theworkpiece 11, there can be used various processing apparatuses such as a cutting apparatus for cutting theworkpiece 11 by an annular cutting blade and a laser processing apparatus for processing theworkpiece 11 by applying a laser beam. In addition, when theback surface 11 b side of theworkpiece 11 is preliminarily ground by thegrinding apparatus 2 to thin theworkpiece 11 prior to the division of theworkpiece 11, thinned device chips are obtained. - It is to be noted, however, that the kind, material, size, shape, structure, and the like of the
workpiece 11 are not limited to any particular ones. For example, theworkpiece 11 may be a wafer (substrate) formed of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramic, resin, metal, or the like. In addition, the kinds, number, shapes, structures, sizes, layout, and the like of the devices are not limited to any particular ones, and theworkpiece 11 may not be formed with the devices. - The
grinding apparatus 2 includes abase 4 for supporting or accommodating each of constituent elements constituting thegrinding apparatus 2. On the upper surface side of thebase 4, arectangular opening 4 a is formed such that the longitudinal direction thereof extends along the X-axis direction. In addition, on the upper surface side of a rear end part of thebase 4, a rectangularparallelepiped support structure 6 is provided along the Z-axis direction. - On the inside of the
opening 4 a, a chuck table (a holding table) 8 for holding theworkpiece 11 is provided. An upper surface of the chuck table 8 is a flat surface substantially parallel to a horizontal plane (XY plane), and constitutes aholding surface 8 a for holding theworkpiece 11. Theholding surface 8 a is connected to a suction source (not illustrated) such as an ejector through a flow channel (not illustrated) formed inside the chuck table 8, a valve (not illustrated), and the like. - An
X-axis moving unit 10 for moving the chuck table 8 along the X-axis direction is connected to the chuck table 8. TheX-axis moving unit 10 is, for example, a ball screw type moving mechanism, and is provided inside theopening 4 a. Specifically, theX-axis moving unit 10 includes an X-axis ball screw (not illustrated) disposed along the X-axis direction and an X-axis pulse motor (not illustrated) for rotating the X-axis ball screw. TheX-axis moving unit 10 includes a flat plate-shaped table cover 12 provided in such a manner as to surround the chuck table 8. On the front side and the rear side of thetable cover 12, bellows-like dustproof and droplet-proof covers 14 capable of contracting and extending in the X-axis direction are provided. Thetable cover 12 and the dustproof and droplet-proof covers 14 are provided in such a manner as to cover the constituent elements (the X-axis ball screw, the X-axis pulse motor, and the like) of theX-axis moving unit 10 accommodated inside theopening 4 a. When theX-axis moving unit 10 is operated, the chuck table 8 is moved in the X-axis direction together with thetable cover 12, and is positioned at a front end part (conveying position) or a rear end part (grinding position) of theopening 4 a. In addition, a rotational drive source (not illustrated) such as a motor for rotating the chuck table 8 around a rotational axis substantially parallel to the Z-axis direction is connected to the chuck table 8. - On a front surface side of the
support structure 6, a Z-axis moving unit 16 is provided. The Z-axis moving unit 16 includes a pair of Z-axis guide rails 18 disposed along the Z-axis direction. A flat plate-shaped Z-axis moving plate 20 is mounted to the pair of Z-axis guide rails 18 in such a manner as to be slidable along the Z-axis guide rails 18. On a back surface side (a rear surface side) of the Z-axis moving plate 20, a nut section (not illustrated) is provided. The nut section is in screw engagement with a Z-axis ball screw 22 disposed along the Z-axis direction between the pair of Z-axis guide rails 18. In addition, a Z-axis pulse motor 24 for rotating the Z-axis ball screw 22 is connected to an end part of the Z-axis ball screw 22. When the Z-axis ball screw 22 is rotated by the Z-axis pulse motor 24, the Z-axis moving plate 20 is moved (lifted or lowered) in the Z-axis direction along the Z-axis guide rails 18. - A
support member 26 is fixed to a front surface side of the Z-axis moving plate 20. Thesupport member 26 supports a grindingunit 28 for grinding theworkpiece 11. The grindingunit 28 includes acylindrical housing 30 supported by thesupport member 26. Acylindrical spindle 32 disposed along the Z-axis direction is accommodated in thehousing 30. A tip end part (a lower end part) of thespindle 32 projects downward from a lower surface of thehousing 30. In addition, a rotational drive source (not illustrated) such as a motor is connected to a base end part (an upper end part) of thespindle 32. - A disk-shaped wheel mount 34 made of metal or the like is fixed to the tip end part of the
spindle 32. Anannular grinding wheel 36 for grinding theworkpiece 11 is detachably mounted to a lower surface side of thewheel mount 34. The grindingwheel 36 includes anannular wheel base 38 and a plurality ofgrindstones 40 fixed to thewheel base 38. The grindingwheel 36 is rotated around a rotational axis substantially parallel to the Z-axis direction by motive power transmitted from the rotational drive source through thespindle 32 and thewheel mount 34. Note that the configuration and functions of thegrinding wheel 36 will be described later (seeFIG. 2 ). - The grinding
apparatus 2 includes a controller (control unit, control section, control device) 42 for controlling the grindingapparatus 2. Thecontroller 42 is connected to each of constituent elements (the chuck table 8, theX-axis moving unit 10, the Z-axis moving unit 16, the grindingunit 28, etc.) of thegrinding apparatus 2. Thecontroller 42 sends control signals to the constituent elements of thegrinding apparatus 2 to thereby control the operation of thegrinding apparatus 2. For example, thecontroller 42 includes a computer. Specifically, thecontroller 42 includes a processing section for performing calculations and the like for the operation of thegrinding apparatus 2 and a storage section for storing various kinds of information (data, a program, and the like) used for the operation of thegrinding apparatus 2. The processing section includes a processor such as a central processing unit (CPU). In addition, the storage section includes a memory such as a read only memory (ROM) and a random access memory (RAM). - In grinding the
workpiece 11 by the grindingapparatus 2, first, theworkpiece 11 is held by the chuck table 8. For example, theworkpiece 11 is disposed on the chuck table 8 such that thefront surface 11 a side faces the holdingsurface 8 a and theback surface 11 b side is exposed to the upper side. In this state, a suction force (negative pressure) of the suction source is made to act on the holdingsurface 8 a, whereby theworkpiece 11 is held under suction by the chuck table 8. Thereafter, the chuck table 8 is moved by theX-axis moving unit 10, and is positioned on the lower side of the grinding wheel 36 (grinding position). Then, while the chuck table 8 and thespindle 32 are rotated at predetermined rotating speeds in respective predetermined directions, the grindingwheel 36 is lowered at a predetermined speed by the Z-axis moving unit 16, to bring thegrindstones 40 into contact with theworkpiece 11. As a result, theback surface 11 b side of theworkpiece 11 is ground away, and theworkpiece 11 is ground and thinned. - Next, a configuration example of the
grinding wheel 36 mounted to the grindingunit 28 of thegrinding apparatus 2 will be described. The grindingwheel 36 is fixed to the wheel mount 34 (seeFIG. 1 ) by fixing means (not illustrated) such as fastening bolts, for example. As a result, the grindingwheel 36 is mounted to the tip end part of thespindle 32 through thewheel mount 34. -
FIG. 2 is a perspective view depicting the grindingwheel 36 including thewheel base 38 and the plurality ofgrindstones 40. For example, thewheel base 38 is formed of such metal as an aluminum alloy, and is formed in an annular shape substantially equal in diameter to the wheel mount 34 (seeFIG. 1 ). In addition, thewheel base 38 includes afirst surface 38 a and asecond surface 38 b which are substantially parallel to each other. Thefirst surface 38 a corresponds to a fixed end face fixed to the wheel mount 34 (seeFIG. 1 ), whereas thesecond surface 38 b corresponds to a free end face which is not fixed to thewheel mount 34. Thewheel base 38 is provided in a central part thereof with anopening 38 c penetrating thewheel base 38 in the thickness direction from thefirst surface 38 a to thesecond surface 38 b. For example, theopening 38 c is formed in a frustoconical shape whose diameter increases from thefirst surface 38 a toward thesecond surface 38 b. On thesecond surface 38 b side of thewheel base 38, anannular groove 38 d is provided. Thegroove 38 d is formed concentrically with thewheel base 38 on the outer circumferential side of thewheel base 38 than theopening 38 c. On the inside of thegroove 38 d, the plurality ofgrindstones 40 for grinding theworkpiece 11 are fixed. - The plurality of
grindstones 40 are each formed, for example, in a rectangular parallelepiped shape, and are arranged in an annular pattern at substantially equal intervals along thegroove 38 d. Note that the width of thegrindstones 40 and the width of thegroove 38 d are substantially equal, and thegrindstones 40 are arranged such that the lengthwise direction (longitudinal direction) thereof is along the tangential direction (circumferential direction) of thegroove 38 d. In addition, thegrindstone 40 includes a rectangular grindingsurface 40 a which is exposed to the side opposite to thewheel base 38. The grindingsurface 40 a is a surface that comes into contact with theworkpiece 11 at the time of grinding, and theworkpiece 11 is ground by the grindingsurface 40 a. - In addition, the
wheel base 38 includes a plurality of grindingliquid supply passages 38 e penetrating thewheel base 38 from thefirst surface 38 a to thesecond surface 38 b. One end side of the grindingliquid supply passage 38 e is opened in thefirst surface 38 a, whereas the other end side of the grindingliquid supply passage 38 e is opened in that region of thesecond surface 38 b which is located between the opening 38 c and thegroove 38 d. The openings of the plurality of grindingliquid supply passages 38 e exposed in thesecond surface 38 b are arranged in an annular pattern at substantially equal intervals along the circumferential direction of thewheel base 38. - As depicted in
FIG. 1 , the grindingwheel 36 is mounted to thewheel mount 34 which is fixed to the tip end part of thespindle 32. When thespindle 32 is rotated in this state, the grindingwheel 36 is rotated around a rotational axis which is substantially parallel to the Z-axis direction. As a result, the plurality ofgrindstones 40 are each rotated (slewed) along an annular rotational route centered on a rotational axis of thegrinding wheel 36. With the grinding surfaces 40 a of therotating grindstones 40 made to come into contact with theworkpiece 11, theworkpiece 11 is ground. - At the time of grinding the
workpiece 11 by the grindingwheel 36, liquid (grinding liquid) such as pure water is supplied to one end side of the grindingliquid supply passage 38 e (thefirst surface 38 a side of the wheel base 38), and the grinding liquid is supplied from the other end side of the grindingliquid supply passage 38 e to theworkpiece 11 and the plurality ofgrindstones 40. As a result, theworkpiece 11 and thegrindstones 40 are cooled, and swarf (grinding swarf) generated by grinding of theworkpiece 11 is washed away. -
FIG. 3 is a sectional view depicting a part of thegrindstone 40. Thegrindstone 40 includesabrasive grains 50 formed of diamond, cubic boron nitride (cBN), or the like and a binder (bonding material) 52 for fixing theabrasive grains 50. As thebinder 52, there can be used a vitreous vitrified bond containing SiO2 or the like as a main constituent, a resin bond containing resin as a main constituent, or the like. In addition, a number of pores (not illustrated) are formed inside thebinder 52. It is to be noted, however, that the material and grain diameter of theabrasive grains 50 and the material of thebinder 52 are not limited to any kind. - The
binder 52 contains a filler (aggregate) 54 for reinforcing thebinder 52. With thefiller 54 contained in thebinder 52, mechanical strength of thebinder 52 is enhanced, and consumption of thegrindstones 40 is suppressed. Particularly, in the present embodiment, aspherical filler 54 is contained in thebinder 52. In other words, thefiller 54 does not have an angular random shape (angular shape), and is particles (powder material) having a true spherical shape or a shape resembling a true sphere. - Specifically, the ratio of a short axis a to a long axis b (aspect ratio a/b) of the
filler 54 is not less than 0.7, preferably not less than 0.8, and more preferably not less than 0.9. The short axis a of thefiller 54 passes through the center (center of gravity) of thefiller 54 and corresponds to the length of a shortest straight line connecting two points on the surface of thefiller 54. Meanwhile, the long axis b of thefiller 54 passes through the center (center of gravity) of thefiller 54 and corresponds to the length of a longest straight line connecting two points on the surface of thefiller 54. For example, in the case where thefiller 54 is in the shape of a long sphere (a body of rotation obtained by rotating an ellipse around the long axis of the ellipse), the short axis a corresponds to a short diameter of thefiller 54, and the long axis b corresponds to a long diameter of thefiller 54. In addition, the circularity of thefiller 54 is, for example, not less than 0.95, preferably not less than 0.96, and more preferably not less than 0.97. Further, the convexity of thefiller 54 is, for example, not less than 0.97, preferably not less than 0.98, and more preferably not less than 0.99, and the solidity of thefiller 54 is, for example, not less than 0.94, preferably not less than 0.95, and more preferably not less than 0.96. For example, spherical ceramic particles formed of aluminum oxide (alumina, Al2O3), silicon dioxide (silica, SiO2), or the like are used as thefiller 54. As a commercial product which can be used as thefiller 54, there may be mentioned true spherical fine particles (trade name: ADMAFINE (registered trademark)) made by ADMATECHS COMPANY LIMITED. - The amount of the
filler 54 contained in thebinder 52 is adjusted according to the strength of thebinder 52 required. Specifically, the content of thefiller 54 in thebinder 52 can be set to be 5 to 90 wt %, and preferably 60 to 80 wt %. This content corresponds to the ratio of the mass of thefiller 54 based on the mass of thebinder 52 in which thefiller 54 is contained (the total of the mass of thebinder 52 and the mass of the filler 54). - Note that it was confirmed, as described later, that, when the
spherical filler 54 is used, the strength of thebinder 52 is high as compared to the case where a filler of an angular shape is used (seeFIG. 4 ). Hence, by thespherical filler 54 being contained in thebinder 52, it is possible to more securely reinforce thebinder 52, and to restrain consumption of thebinder 52. In addition, as described later, it was also confirmed that the strength of thebinder 52 is higher as the size of thefiller 54 is greater (seeFIG. 4 ). Hence, it is preferable that the average particle diameter of thefiller 54 be greater than the average particle diameter of theabrasive grains 50. For example, the average particle diameter of thefiller 54 is 1.1 to 20 times the average particle diameter of theabrasive grains 50. The particle diameters of theabrasive grains 50 and thefiller 54 can be measured, for example, by a laser diffraction method. - Note that, in the case where the
filler 54 has an angular shape, when the average particle diameter of thefiller 54 is set larger than the average particle diameter of theabrasive grains 50, the sharp angular parts of thefiller 54 largely project from thebinder 52 to be liable to collide against theworkpiece 11, and defective processing may occur. On the other hand, when thespherical filler 54 is used as in the present embodiment, even if thefiller 54 projects from thebinder 52, only a smooth surface (curved surface) of thefiller 54 would make contact with theworkpiece 11. Hence, even when the average particle diameter of thefiller 54 is greater than the average particle diameter of theabrasive grains 50, damaging of theworkpiece 11 by thefiller 54 is not liable to occur, and defective processing is restrained. - As described above, in the
grindstones 40 according to the present embodiment, thebinder 52 for fixing theabrasive grains 50 contains thespherical filler 54. As a result, it is possible to restrain occurrence of defective processing at the time of processing theworkpiece 11 by thegrindstones 40, while enhancing the strength of thegrindstones 40. - Note that the structures, methods, and the like concerning the above embodiment can appropriately be modified in carrying out the present invention insofar as the modifications do not depart from the scope of the object of the invention.
- Next, the results of evaluation of the strength of the grindstones according to the present invention will be described. In this evaluation, a plurality of grindstones in which the material and size of the filler contained in the binder differ were formed, and the strength of each of the grindstones was measured.
- In this evaluation, a plurality of rectangular parallelepiped grindstones (with the length of 20 mm, the width of 10 mm, and the thickness of 4 mm) containing no abrasive grains but fillers in the binder (vitrified bons) were used. Specifically, a grindstone A containing aluminum oxide of an angular shape as the filler, a grindstone B containing spherical aluminum oxide as the filler, and a grindstone C containing spherical silicon dioxide as the filler were formed. More specifically, two kinds of grindstones A, four kinds of grindstones B, and three kinds of grindstones C, which were different in particle diameter of the filler, were prepared. The particle diameters of the filler (aluminum oxide of angular shape) contained in the two kinds of grindstones A were 0.5 μm and 2 μm. The particle diameters of the filler (spherical aluminum oxide) contained in the four kinds of grindstones B were 0.7 μm, 4.2 μm, 5 μm, and 5.4 μm. The particle diameters of the filler (spherical silicon dioxide) contained in the three kinds of grindstones C were 1.6 μm, 3 μm, and 5.7 μm.
- For the total of nine kinds of grindstones, measurement of strength (bending stress) by a three-point bending test was conducted.
FIG. 4 is a graph depicting the measurement results of the strength of the grindstones. - As depicted in
FIG. 4 , it was confirmed that the strengths of the grindstones B and C using the spherical fillers are higher than the strength of the grindstone A using the filler of the angular shape having the equivalent size. It is conjectured that this difference comes from such facts that, on one hand, the filler of the angular shape is liable to generate cracks in the inside of the binder by sharp angular parts, and, on the other hand, the spherical fillers make contact with the binder by their smooth surfaces and, hence, are not liable to generate cracks in the inside of the binder. - In addition, comparison of the strengths of the grindstones B and C has verified that the grindstone B containing spherical aluminum oxide is higher in strength than the grindstone C containing silicon dioxide. It is conjectured that the aluminum oxide particles are higher in strength than the silicon dioxide particles, and the strengths of the fillers are reflected on the strengths of the grindstones B and C.
- Further, in any one of the grindstones A, B, and C, the strength of the grindstone was higher as the particle diameter of the filler was greater. As a result, it was confirmed that enlargement of the filler is effective for enhancing the strength of the grindstone. Specifically, by use of spherical aluminum oxide as the filler, a grindstone B having a strength of not less than 10 MPa, not less than 30 MPa, or not less than 40 MPa was obtained. In addition, by use of spherical silicon dioxide as the filler, a grindstone C having a strength of not less than 5 MPa or not less than 10 MPa was obtained.
- The present invention is not limited to the details of the above described preferred embodiment. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalence of the scope of the claims are therefore to be embraced by the invention.
Claims (5)
1. A grindstone comprising:
abrasive grains; and
a binder for fixing the abrasive grains,
wherein the binder contains a spherical filler for reinforcing the binder.
2. The grindstone according to claim 1 ,
wherein an average particle diameter of the filler is greater than an average particle diameter of the abrasive grains.
3. The grindstone according to claim 1 ,
wherein the filler is ceramic particles, and
a ratio of a short axis to a long axis of the ceramic particles is not less than 0.7.
4. The grindstone according to claim 1 ,
wherein a content of the filler in the binder is 5 to 90 wt %.
5. The grindstone according to claim 1 ,
wherein the binder is a vitrified bond or a resin bond.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2022138453A JP2024034299A (en) | 2022-08-31 | 2022-08-31 | whetstone |
JP2022-138453 | 2022-08-31 |
Publications (1)
Publication Number | Publication Date |
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US20240066665A1 true US20240066665A1 (en) | 2024-02-29 |
Family
ID=89475006
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US18/446,658 Pending US20240066665A1 (en) | 2022-08-31 | 2023-08-09 | Grindstone |
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US (1) | US20240066665A1 (en) |
JP (1) | JP2024034299A (en) |
KR (1) | KR20240031029A (en) |
CN (1) | CN117620917A (en) |
CH (1) | CH719873B1 (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP4154067B2 (en) | 1999-04-06 | 2008-09-24 | 株式会社ディスコ | Grinding equipment |
JP4769488B2 (en) | 2004-05-20 | 2011-09-07 | 株式会社ディスコ | Vitrified bond grinding wheel manufacturing method |
-
2022
- 2022-08-31 JP JP2022138453A patent/JP2024034299A/en active Pending
-
2023
- 2023-07-26 KR KR1020230097382A patent/KR20240031029A/en unknown
- 2023-08-09 US US18/446,658 patent/US20240066665A1/en active Pending
- 2023-08-25 CH CH000907/2023A patent/CH719873B1/en unknown
- 2023-08-28 CN CN202311091233.2A patent/CN117620917A/en active Pending
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CN117620917A (en) | 2024-03-01 |
JP2024034299A (en) | 2024-03-13 |
KR20240031029A (en) | 2024-03-07 |
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