JP5123029B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding apparatus for grinding a workpiece such as a semiconductor wafer.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual semiconductor chips. In addition, optical device wafers in which gallium nitride compound semiconductors are laminated on the surface of sapphire substrates and silicon carbide (SiC) substrates are also cut into individual optical devices such as light-emitting diodes and laser diodes by cutting along the streets. Widely used in electrical equipment. The wafer divided in this way is ground to a predetermined thickness by a grinding device before being cut along the street.

A grinding apparatus for grinding a back surface of a semiconductor wafer includes a chuck table having a holding surface for holding the wafer, and a grinding unit having a grinding wheel having an annular grinding wheel for grinding the wafer held on the chuck table. And a grinding feed mechanism for grinding and feeding the grinding unit in a direction perpendicular to the holding surface of the chuck table. (For example, see Patent Document 1)
JP 2007-222986 A

  Therefore, since the wafer substrate on which optical devices such as LEDs are formed is made of a material with high Mohs hardness such as sapphire or silicon carbide (SiC), a grinding wheel in which diamond abrasive grains are hardened by vitrified bonds or the like. However, it is difficult to grind the back surface. That is, when a wafer made of a silicon carbide (SiC) substrate is ground with a grinding machine having high mechanical rigidity, it can be ground relatively well. However, when a wafer made of a sapphire substrate is ground, there is a problem that the wafer is broken. Further, grinding a wafer made of a silicon carbide (SiC) substrate with a grinding machine having low mechanical rigidity makes it difficult to grind the wafer, but grinding a wafer made of a sapphire substrate enables relatively good grinding.

  The present invention has been made in view of the above facts, and the main technical problem thereof is that even a workpiece made of a material having a high Mohs hardness such as sapphire or silicon carbide (SiC) can be ground well. It is to provide a grinding apparatus.

In order to solve the above main technical problem, according to the present invention, a chuck table mechanism including a chuck table having a holding surface for holding a workpiece, and a workpiece held on the holding surface of the chuck table are provided. In a grinding apparatus comprising grinding means for grinding, and grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table,
The grinding means includes a rotary spindle provided with a thrust plate on the outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, a plate storage space for storing the thrust plate, and the plate storage A spindle housing having a thrust bearing portion having a plurality of fluid supply holes respectively opening in a plurality of regions of the space, a wheel mount provided at the lower end of the rotary spindle, and a grinding wheel attached to the wheel mount; Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber of the plate storage chamber through the plurality of fluid supply holes of the radial bearing portion and the thrust bearing portion;
The fluid supply means includes support stiffness adjusting means for adjusting a support stiffness of the thrust plate by adjusting a supply region of fluid supplied to the plate housing chamber through the plurality of fluid supply holes.
A grinding device is provided.

  The support rigidity adjusting means includes selection means for selecting a fluid to be supplied to the plurality of fluid supply holes.

In addition, according to the present invention, a chuck table mechanism including a chuck table having a holding surface for holding a workpiece, and a grinding means for grinding the workpiece held on the holding surface of the chuck table; A grinding apparatus comprising a grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table,
The chuck table mechanism includes a rotary spindle having an upper end coupled to the chuck table and a thrust plate provided on an outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, and the thrust plate. A spindle housing having a thrust housing portion having a plate housing space to be accommodated and a plurality of fluid supply holes that open to a plurality of regions of the plate housing space, the radial bearing portion, and the plurality of fluid supplies of the thrust bearing portion Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber through holes;
The fluid supply means includes support stiffness adjusting means for adjusting a support stiffness of the thrust plate by adjusting a supply region of fluid supplied to the plate housing chamber through the plurality of fluid supply holes.
A grinding device is provided.

  The support rigidity adjusting means includes selection means for selecting a fluid to be supplied to the plurality of fluid supply holes.

Furthermore, according to the present invention, a chuck table mechanism having a chuck table having a holding surface for holding a workpiece, and a grinding means for grinding the workpiece held on the holding surface of the chuck table; A grinding apparatus comprising a grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table,
The grinding means includes a rotary spindle provided with a thrust plate on the outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, a plate storage space for storing the thrust plate, and the plate storage A spindle housing having a thrust bearing portion having a plurality of fluid supply holes respectively opening in a plurality of regions of the space, a wheel mount provided at the lower end of the rotary spindle, and a grinding wheel attached to the wheel mount; Fluid supply means for supplying fluid to the plurality of regions of the plate housing chamber through the plurality of fluid supply holes of the radial bearing portion and the thrust bearing portion is provided, and the fluid supply means passes through the plurality of fluid supply holes. Adjusting the supply area of the fluid supplied to the plate storage chamber and adjusting the support rigidity of the thrust plate Comprises a supporting rigidity adjusting means that,
The chuck table mechanism includes a rotary spindle having an upper end coupled to the chuck table and a thrust plate provided on an outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, and the thrust plate. A spindle housing having a thrust housing portion having a plate housing space to be accommodated and a plurality of fluid supply holes that open to a plurality of regions of the plate housing space, the radial bearing portion, and the plurality of fluid supplies of the thrust bearing portion Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber through holes, the fluid supply means adjusting the supply region of fluid supplied to the plate storage chamber through the plurality of fluid supply holes; A support stiffness adjusting means for adjusting the support stiffness of the thrust plate is provided.
A grinding device is provided.

A grinding apparatus according to the present invention adjusts a supply area of a fluid supplied to a plate housing chamber that is formed in a spindle housing that fluidly supports a rotating spindle of a grinding means and that is provided on the rotating spindle, and supports the thrust plate. Since the supporting rigidity adjusting means for adjusting the rigidity is provided, the supporting rigidity can be adjusted in accordance with the material forming the substrate of the wafer as the workpiece, so that the wafer held on the chuck table is always kept. It can be ground well.
Further, the grinding apparatus according to the present invention supplies a fluid to be supplied to a plate housing chamber that is formed in a spindle housing that fluidly supports a rotating spindle connected to the chuck table of the chuck table mechanism and accommodates a thrust plate provided on the rotating spindle. Since the support rigidity adjusting means for adjusting the region and adjusting the support rigidity of the thrust plate is provided, the support rigidity can be adjusted in accordance with the material forming the wafer substrate that is the workpiece. The wafer held on the chuck table can always be ground well.

Preferred embodiments of a grinding apparatus constructed according to the present invention will be described below in more detail with reference to the accompanying drawings.
FIG. 1 shows a perspective view of a grinding apparatus constructed in accordance with the present invention. The grinding apparatus shown in FIG. 1 is provided with an apparatus housing generally indicated by numeral 2. This device housing 2 has a rectangular parallelepiped main portion 21 that extends long and an upright wall 22 that is provided at the rear end portion (upper right end in FIG. 1) of the main portion 21 and extends substantially vertically upward. ing. A pair of guide rails 221 and 221 extending in the vertical direction are provided on the front surface of the upright wall 22. A grinding unit 3 as grinding means is mounted on the pair of guide rails 221 and 221 so as to be movable in the vertical direction.

  The grinding unit 3 includes a moving base 31 and a spindle unit 4 mounted on the moving base 31. The movable base 31 is provided with a pair of legs 311 and 311 extending in the vertical direction on both sides of the rear surface. The pair of legs 311 and 311 is slidably engaged with the pair of guide rails 221 and 221. Guided grooves 312 and 312 are formed. As described above, a support portion 313 protruding forward is provided on the front surface of the movable base 31 slidably mounted on the pair of guide rails 221 and 221 provided on the upright wall 22. The spindle unit 4 is attached to the support portion 313.

  The spindle unit 4 includes a cylindrical spindle housing 41 mounted on the support portion 313 and a rotating spindle 42 that is rotatably disposed on the spindle housing 41. The spindle unit 4 will be described with reference to FIG. A rotating spindle 42 shown in FIG. 2 is provided with a thrust plate 421 that protrudes in the radial direction on the outer peripheral surface, and a lower end portion of the rotating spindle 42 protrudes downward from a lower end of the spindle housing 41. A wheel mount 43 is provided at the lower end of the rotary spindle 42, and a grinding wheel 44 is attached to the lower surface of the wheel mount 43. The grinding wheel 44 includes an annular wheel base 441 and a plurality of grinding wheels 442 mounted on the lower surface of the wheel base 441, and the wheel base 441 is attached to the lower surface of the wheel mount 43 by fastening bolts 45. Mounted.

  A cylindrical spindle housing 41 that rotatably supports the rotary spindle 42 includes a shaft hole 411 that penetrates in the axial direction. The rotating spindle 42 is disposed through a shaft hole 411 formed in the spindle housing 41. A plurality of annular fluid supply grooves 412a, 412b, 412c, 412d, and 412e are formed on the inner peripheral surface of the central portion of the shaft hole 411 formed in the spindle housing 41 at predetermined intervals in the axial direction. The spindle housing 41 includes a plurality of fluid supply holes 413a, 413b, 413c, 413d, and 413e that open to the plurality of annular fluid supply grooves 412a, 412b, 412c, 412d, and 412e, and the fluid supply holes 413a, A communication path 414 communicating with 413b, 413c, 413d, and 413e is formed. This communication path 414 is connected to a fluid supply means described later. Accordingly, by supplying a high-pressure fluid such as high-pressure air, high-pressure water, and high-pressure oil by a fluid supply means described later, a plurality of annular shapes are provided via the communication passage 414 and the plurality of fluid supply holes 413a, 413b, 413c, 413d, and 413e. The high pressure fluid is supplied to the fluid supply grooves 412a, 412b, 412c, 412d, and 412e. As a result, a fluid layer is formed by the high-pressure fluid between the inner peripheral surface of the shaft hole 411 of the spindle housing 41 and the outer peripheral surface of the rotary spindle 42, and the rotary spindle 42 is fluidly supported by the fluid layer in a freely rotatable manner. Accordingly, the inner peripheral surface of the shaft hole 411 of the spindle housing 41 and the plurality of annular fluid supply grooves 412a, 412b, 412c, 412d, 412e and the plurality of fluid supply holes 413a, 413b, 413c, 413d, 413e Functions as a radial bearing that rotatably supports the fluid.

  A plate accommodation chamber 415 for accommodating a thrust plate 421 provided on the rotary spindle 42 is formed in the lower portion of the spindle housing 41. A plurality of annular fluid supply grooves 416a, 416b, and 416c having different diameters around the shaft hole 411 are formed in the upper wall 415a forming the plate housing chamber 415 at predetermined intervals in the radial direction. A plurality of regions are defined by the plurality of annular fluid supply grooves 416a, 416b, and 416c. A plurality of annular fluid supply grooves 417a, 417b, and 417c having different diameters around the shaft hole 411 are formed in the lower wall 415b forming the plate storage chamber 415 at predetermined intervals in the radial direction. A plurality of regions are defined by the plurality of annular fluid supply grooves 417a, 417b, and 417c. Further, the spindle housing 41 has a plurality of fluid supply holes 418a, 418b, 418c that open to the plurality of annular fluid supply grooves 416a, 416b, 416c and 417a, 417b, 417c, respectively, and the plurality of fluid supply holes 418a, A plurality of communication passages 419a, 419b, 419c communicating with 418b, 418c, respectively, are formed. The plurality of communication passages 419a, 419b, 419c are connected to a fluid supply means described later. Accordingly, by supplying a high-pressure fluid such as high-pressure air, high-pressure water, and high-pressure oil by a fluid supply means, which will be described later, a plurality of communication paths 419a, 419b, 419c, a plurality of fluid supply holes 418a, 418b, 418c and a plurality of annular shapes The high pressure fluid is supplied to the plate accommodating chamber 415 through the fluid supply grooves 416a, 416b, 416c and 417a, 417b, 417c. As a result, a fluid layer is formed by the high-pressure fluid between the upper wall 415a and the lower wall 415b of the plate accommodating chamber 415 and the thrust plate 421, and the thrust plate 421 is fluid-supported by the fluid layer. Accordingly, the plate accommodating chamber 415, the plurality of annular fluid supply grooves 416a, 416b, 416c and 417a, 417b, 417c and the plurality of fluid supply holes 418a, 418b, 418c fluidly support the thrust plate 421 in the axial direction. Functions as a thrust bearing.

  The spindle unit 4 in the illustrated embodiment includes an electric motor 46 for driving the rotary spindle 42 to rotate. The illustrated electric motor 46 is a permanent magnet motor. The permanent magnet type electric motor 46 is disposed in the spindle housing 41 on the outer peripheral side of the rotor 461 and a rotor 461 made of a permanent magnet mounted on a motor mounting portion 422 formed at the upper end of the rotary spindle 42. It consists of a stator coil 462. The electric motor 46 configured as described above rotates the rotor 461 by applying AC power to the stator coil 462, and rotates the rotary spindle 42 to which the rotor 461 is mounted.

  Continuing with reference to FIG. 2, the grinding unit 3 as the grinding means in the illustrated embodiment includes a fluid supply means 47 for supplying fluid to the radial bearing portion and the thrust bearing portion. The fluid supply means 47 includes a high-pressure fluid source 471 such as high-pressure air, high-pressure water, and high-pressure oil; a radial bearing pipe 472 that connects the high-pressure fluid source 471 and the communication path 414 formed in the spindle housing 41; Thrust bearing piping 473a, 473b, 473c for connecting the fluid source 471 and the communication passages 419a, 419b, 419c formed in the spindle housing 41, respectively, and the electromagnetic on-off valve 474 and the thrust bearing disposed in the radial bearing piping 472 The pipes 473a, 473b, and 473c are provided with electromagnetic on-off valves 475a, 475b, and 475c, respectively. The electromagnetic on-off valves 474 and the electromagnetic on-off valves 475a, 475b, and 475c are controlled by control means (not shown). In the illustrated embodiment, the electromagnetic on-off valves 474 and 475a, 475b, 475c are closed when deenergized (OFF), and are opened when energized (ON). Has been.

  The fluid supply means 47 in the illustrated embodiment is configured as described above. When the electromagnetic on-off valve 474 is energized (ON), the high-pressure fluid from the high-pressure fluid source 471 is fed to the radial bearing pipe 472 and the communication path 414. The inner peripheral surface of the shaft hole 411 of the spindle housing 41 and the rotary spindle 42 from the plurality of annular fluid supply grooves 412a, 412b, 412c, 412d, 412e through the plurality of fluid supply holes 413a, 413b, 413c, 413d, 413e. Supplied between. As a result, a fluid layer is formed between the inner peripheral surface of the shaft hole 411 of the spindle housing 41 and the outer peripheral surface of the rotary spindle 42, and the rotary spindle 42 is rotatably supported by the fluid layer. Further, when the electromagnetic on-off valves 475a, 475b, and 475c are energized (ON), the high-pressure fluid of the high-pressure fluid source 461 causes the thrust bearing pipes 473a, 473b, and 473c and the plurality of communication passages 419a, 419b, and 419c to The plate storage chamber 415 is supplied from a plurality of annular fluid supply grooves 416a, 416b, 416c and 417a, 417b, 417c through the fluid supply holes 418a, 418b, 418c. As a result, a fluid layer is formed by the high-pressure fluid supplied between the upper wall 415a and lower wall 415b of the plate accommodation chamber 415 and the thrust plate 421, and the thrust plate 421 accommodated in the plate accommodation chamber 415 by this fluid layer. Is fluidly supported in the axial direction. In addition, by selecting and energizing (ON) the electromagnetic on-off valves 475a, 475b, and 475c respectively disposed in the thrust bearing pipes 473a, 473b, and 473c, a fluid supply region to be supplied to the plate housing chamber 415 is set. By adjusting, the support rigidity of the thrust plate 421 can be adjusted. Accordingly, the thrust bearing pipes 473a, 473b, and 473c and the electromagnetic on-off valves 475a, 475b, and 475c provided in the thrust bearing pipes 473a, 473b, and 473c, respectively, serve as support rigidity adjusting means for adjusting the support rigidity of the thrust plate 421. Function. Further, the electromagnetic on-off valves 475a, 475b, 475c constituting the support rigidity adjusting means function as a selection means for selecting a fluid to be supplied to the plurality of fluid supply holes 418a, 418b, 418c.

  In the above-described embodiment, the plurality of annular fluid supply grooves 416a, 416b, 416c and the plate formed in the upper wall 415a forming the plate housing chamber 415 via the plurality of fluid supply holes 418a, 418b, 418c. Although an example in which high-pressure fluid is supplied to the plurality of annular fluid supply grooves 417a, 417b, and 417c formed in the lower wall 415b that forms the storage chamber 415 has been shown, it is formed in the upper wall 415a that forms the plate storage chamber 415. Independent fluid supply holes are respectively connected to the plurality of annular fluid supply grooves 416a, 416b, 416c and the plurality of annular fluid supply grooves 417a, 417b, 417c formed in the lower wall 415b forming the plate accommodating chamber 415. The fluid supplied to the independent fluid supply hole may be selected. With this configuration, it is possible to change the support rigidity due to the high-pressure fluid acting on the upper side of the thrust plate 421 and the support rigidity due to the high-pressure fluid acting on the lower side of the thrust plate 421.

  Referring back to FIG. 1, the grinding apparatus in the illustrated embodiment moves the grinding unit 3 up and down along the pair of guide rails 221 and 221 (perpendicular to a holding surface of a chuck table described later). Grinding feeding means 5 that is moved in the direction) is provided. The grinding feed means 5 includes a male threaded rod 51 disposed on the front side of the upright wall 22 and extending substantially vertically. The male screw rod 51 is rotatably supported by bearing members 52 and 53 whose upper end and lower end are attached to the upright wall 22. The upper bearing member 52 is provided with a pulse motor 54 as a drive source for rotationally driving the male screw rod 51, and an output shaft of the pulse motor 54 is transmission-coupled to the male screw rod 51. A connecting portion (not shown) that protrudes rearward from the center portion in the width direction is also formed on the rear surface of the movable base 31, and a through female screw hole (not shown) that extends in the vertical direction is formed in this connecting portion. The male screw rod 51 is screwed into the female screw hole. Therefore, when the pulse motor 54 rotates forward, the moving base 31, that is, the grinding unit 3 is lowered or moved forward, and when the pulse motor 54 reversely moves, the moving base 31, that is, the grinding unit 3 is raised or moved backward.

  Continuing the description with reference to FIG. 1, the chuck table mechanism 6 is disposed in the main portion 21 of the housing 2. The chuck table mechanism 6 includes a chuck table 61, a cover member 62 that covers the periphery of the chuck table 61, and bellows means 63 and 64 disposed before and after the cover member 62. The chuck table 62 is configured to be rotated by a spindle unit, which will be described later, and is configured to suck and hold a wafer, which is a workpiece, on its upper surface by operating a suction means described later. Further, the chuck table 61 is moved between a workpiece placement area 24 shown in FIG. 1 and a grinding area 25 facing the grinding wheel 44 constituting the spindle unit 4 of the grinding unit 3 by means of a chuck table moving means described later. It can be moved. The bellows means 63 and 64 can be formed from any suitable material such as campus cloth. The front end of the bellows means 63 is fixed to the front wall of the main portion 21, and the rear end is fixed to the front end surface of the cover member 62. The front end of the bellows means 64 is fixed to the rear end surface of the cover member 62, and the rear end is fixed to the front surface of the upright wall 22 of the apparatus housing 2. When the chuck table 61 is moved in the direction indicated by the arrow 23a, the bellows means 63 is expanded and the bellows means 64 is contracted, and when the chuck table 612 is moved in the direction indicated by the arrow 23b, the bellows means 63 is The bellows means 64 is expanded by contraction.

Next, the chuck table 61 and the spindle unit 7 for rotationally driving the chuck table 61 will be described with reference to FIG.
The chuck table 61 shown in FIG. 3 includes a chuck table main body 611 and a suction holding chuck 612 disposed on the upper surface of the chuck table main body 611. The chuck table main body 611 is formed in a disc shape by a metal material such as stainless steel, and a circular fitting recess 611a is formed on the upper surface, and an annular mounting portion is provided on the outer periphery of the bottom surface of the fitting recess 611a. A shelf 611b is provided. Then, the suction holding chuck 612 formed by a porous member made of porous ceramics or the like having countless suction holes is fitted into the fitting recess 611a. Thus, the suction holding chuck 612 fitted in the fitting recess 611a formed in the chuck table main body 611 functions as a holding surface for sucking and holding the workpiece. A suction passage 611c communicating with the fitting recess 611a is formed at the center of the chuck table body 611. The suction passage 611c is connected to suction means described later.

  3, the spindle unit 7 for rotationally driving the chuck table 61 is rotated by the cylindrical spindle housing 71 disposed on the lower side of the chuck table 61 and the spindle housing 71. And a freely rotating spindle 72. The rotary spindle 72 is provided with a thrust plate 721 that protrudes in the radial direction on the outer peripheral surface, and an upper end portion of the rotary spindle 72 protrudes upward from an upper end of the spindle housing 71. The lower surface of the chuck table 61 is joined to the upper end of the rotating spindle 72. A communication passage 722 extending in the axial direction is formed at the center of the rotary spindle 72, and the upper end of the communication passage 722 communicates with a suction passage 611 c formed in the chuck table body 611 of the chuck table 61. ing. The rotating spindle 72 thus configured has a lower end projecting downward from the lower end of the spindle housing 71, and the rotating spindle 72 has a rotary joint 73 communicating with the lower end of the communication path 722. Is installed. The passage 731 formed in the rotary joint 73 is connected to the suction means 74. The suction means 74 includes a suction source 741, a suction pipe 742 that connects the suction source 741 and a passage 731 formed in the rotary joint 73, and an electromagnetic opening / closing valve 743 disposed in the suction pipe 742. The electromagnetic on-off valve 743 is controlled by control means (not shown). In the illustrated embodiment, the electromagnetic on-off valve 743 is closed when de-energized (OFF), and is configured to open when energized (ON). Therefore, when the electromagnetic on-off valve 743 is energized (ON), it is sucked from the suction source 741 through the suction pipe 742, the passage 731 formed in the rotary joint 73, the communication passage 722, the suction passage 611c, and the fitting recess 611a. A negative pressure is applied to the holding surface, which is the upper surface of the holding chuck 612.

  Next, a cylindrical spindle housing 71 that rotatably supports the rotary spindle 72 will be described. The spindle housing 71 shown in FIG. 3 includes a shaft hole 711 penetrating in the axial direction. The rotating spindle 72 is disposed through a shaft hole 711 formed in the spindle housing 71. A plurality of annular fluid supply grooves 712a, 712b, 712c, 712d, and 712e are formed on the inner peripheral surface of the central portion of the shaft hole 711 formed in the spindle housing 71 at predetermined intervals in the axial direction. Further, the spindle housing 71 has a plurality of fluid supply holes 713a, 713b, 713c, 713d, 713e opened to the plurality of annular fluid supply grooves 712a, 712b, 712c, 712d, 712e, and the plurality of fluid supply holes. A communication path 714 that communicates with 713a, 713b, 713c, 713d, and 713e is formed. This communication path 714 is connected to a fluid supply means described later. Accordingly, by supplying a high-pressure fluid such as high-pressure air, high-pressure water, and high-pressure oil by a fluid supply means described later, a plurality of annular shapes are provided via the communication path 714 and the plurality of fluid supply holes 713a, 713b, 713c, 713d, and 713e. High-pressure fluid is supplied to the fluid supply grooves 712a, 712b, 712c, 712d, and 712e. As a result, a fluid layer is formed by the high pressure fluid between the inner peripheral surface of the shaft hole 711 of the spindle housing 71 and the outer peripheral surface of the rotary spindle 72, and the rotary spindle 72 is fluidly supported by the fluid layer in a freely rotatable manner. Therefore, the inner peripheral surface of the shaft hole 711 of the spindle housing 71, the plurality of annular fluid supply grooves 712a, 712b, 712c, 712d, 712e and the plurality of fluid supply holes 713a, 713b, 713c, 713d, 713e Functions as a radial bearing that rotatably supports the fluid.

  A plate accommodation chamber 715 for accommodating a thrust plate 721 provided on the rotary spindle 72 is formed in the upper portion of the spindle housing 71. A plurality of annular fluid supply grooves 716a, 716b, 716c having different diameters around the shaft hole 711 are formed in the upper wall 715a forming the plate housing chamber 715 at predetermined intervals in the radial direction. A plurality of regions are defined by the plurality of annular fluid supply grooves 716a, 716b, and 716c. In addition, a plurality of annular fluid supply grooves 717a, 717b, and 717c having different diameters around the shaft hole 711 are formed in the lower wall 715b forming the plate accommodating chamber 715 at predetermined intervals in the radial direction. The plurality of annular fluid supply grooves 717a, 717b, and 717c define a plurality of regions. The spindle housing 71 has a plurality of fluid supply holes 718a, 718b, 718c that open to the plurality of annular fluid supply grooves 716a, 716b, 716c and 717a, 717b, 717c, respectively, and the plurality of fluid supply holes 718a, A plurality of communication passages 719a, 719b, 719c communicating with 718b, 718c, respectively, are formed. The plurality of communication passages 719a, 719b, 719c are connected to a fluid supply means described later. Accordingly, by supplying a high-pressure fluid such as high-pressure air, high-pressure water, or high-pressure oil by a fluid supply means described later, a plurality of communication passages 719a, 719b, 719c, a plurality of fluid supply holes 718a, 718b, 718c and a plurality of annular shapes are provided. The high-pressure fluid is supplied to the plate accommodating chamber 715 through the fluid supply grooves 716a, 716b, 716c and 717a, 717b, 717c. As a result, a fluid layer is formed by the high-pressure fluid between the upper wall 715a and the lower wall 715b of the plate housing chamber 715 and the thrust plate 721, and the thrust plate 721 is fluid-supported by the fluid layer. Accordingly, the plate accommodating chamber 715, the plurality of annular fluid supply grooves 716a, 716b, 716c and 717a, 717b, 717c and the plurality of fluid supply holes 718a, 718b, 718c fluidly support the thrust plate 721 in the axial direction. Functions as a thrust bearing.

  The spindle unit 7 in the illustrated embodiment includes an electric motor 75 for driving the rotary spindle 72 to rotate. The illustrated electric motor 75 is a permanent magnet motor. The permanent magnet type electric motor 75 is disposed on the spindle housing 71 on the outer peripheral side of the rotor 751 and a rotor 751 made of a permanent magnet mounted on a motor mounting portion 723 formed at the upper end of the rotary spindle 72. The stator coil 752 is included. In the electric motor 75 configured in this manner, the rotor 751 is rotated by applying AC power to the stator coil 752, and the rotating spindle 72 to which the rotor 751 is mounted is rotated.

  Continuing with reference to FIG. 3, the chuck table mechanism 6 in the illustrated embodiment includes fluid supply means 76 for supplying fluid to the radial bearing portion and the thrust bearing portion. The fluid supply means 76 includes a high-pressure fluid source 761 such as high-pressure air, high-pressure water, and high-pressure oil; a radial bearing pipe 762 that connects the high-pressure fluid source 761 and the communication path 714 formed in the spindle housing 71; Thrust bearing pipes 763a, 763b, and 763c that connect the fluid source 761 and the communication passages 719a, 719b, and 719c formed in the spindle housing 71, respectively, an electromagnetic on-off valve 764 and a thrust bearing disposed in the radial bearing pipe 762 The on-off valves 765a, 765b, and 765c are disposed in the pipes 763a, 763b, and 763c, respectively. The electromagnetic on-off valves 764 and the on-off valves 765a, 765b, and 765c are controlled by control means (not shown). In the illustrated embodiment, the electromagnetic on-off valves 764 and 765a, 765b, and 765c are closed when deenergized (OFF), and are opened when energized (ON). Has been.

  The fluid supply means 76 in the illustrated embodiment is configured as described above. When the electromagnetic on-off valve 764 is energized (ON), the high-pressure fluid of the high-pressure fluid source 761 is supplied to the radial bearing pipe 762 and the communication path 714. The inner peripheral surface of the shaft hole 711 of the spindle housing 71 and the rotary spindle 72 from the plurality of annular fluid supply grooves 712a, 712b, 712c, 712d, 712e through the plurality of fluid supply holes 713a, 713b, 713c, 713d, 713e. Supplied between. As a result, a fluid layer is formed between the inner peripheral surface of the shaft hole 711 of the spindle housing 71 and the outer peripheral surface of the rotary spindle 72, and the rotary spindle 72 is fluidly supported by the fluid layer in a freely rotatable manner. Further, when the electromagnetic on-off valves 765a, 765b, 765c are energized (ON), the high-pressure fluid of the high-pressure fluid source 761 is thrust bearing pipes 763a, 763b, 763c, the plurality of communication passages 719a, 719b, 719c, and the plurality. A plurality of annular fluid supply grooves 716a, 716b, 716c and 717a, 717b, 717c are supplied to the plate storage chamber 715 through the fluid supply holes 718a, 718b, 718c. As a result, a fluid layer is formed by the high-pressure fluid supplied between the upper wall 715a and lower wall 715b of the plate accommodation chamber 715 and the thrust plate 721, and the thrust plate 721 accommodated in the plate accommodation chamber 715 by this fluid layer. Is fluidly supported in the axial direction. It is to be noted that a fluid supply region to be supplied to the plate accommodating chamber 715 is selected by energizing (ON) the electromagnetic on-off valves 765a, 765b, and 765c disposed in the thrust bearing pipes 763a, 763b, and 763c, respectively. By adjusting, the support rigidity of the thrust plate 721 can be adjusted. Therefore, the thrust bearing pipes 763a, 763b, and 763c and the electromagnetic on-off valves 765a, 765b, and 765c respectively disposed in the thrust bearing pipes 763a, 763b, and 763c serve as support rigidity adjusting means for adjusting the support rigidity of the thrust plate 721. Function. Further, the electromagnetic on-off valves 765a, 765b, 765c constituting the support rigidity adjusting means function as a selection means for selecting a fluid to be supplied to the plurality of fluid supply holes 718a, 718b, 718c.

  In the above-described embodiment, the plurality of annular fluid supply grooves 716a, 716b, 716c and the plate formed in the upper wall 715a forming the plate housing chamber 715 via the plurality of fluid supply holes 718a, 718b, 718c. Although an example in which high-pressure fluid is supplied to the plurality of annular fluid supply grooves 717a, 717b, and 717c formed in the lower wall 715b that forms the storage chamber 715 has been shown, it is formed in the upper wall 715a that forms the plate storage chamber 715. Independent fluid supply holes are respectively connected to the plurality of annular fluid supply grooves 716a, 716b, 716c and the plurality of annular fluid supply grooves 717a, 717b, 717c formed in the lower wall 715b forming the plate accommodating chamber 715. The fluid supplied to the independent fluid supply hole may be selected. With this configuration, it is possible to change the support rigidity due to the high-pressure fluid acting on the upper side of the thrust plate 721 and the support rigidity due to the high-pressure fluid acting on the lower side of the thrust plate 721.

  The chuck table mechanism 6 in the illustrated embodiment includes the workpiece table mounting area 24 shown in FIG. 1 for the chuck table 61 and a grinding area 25 facing the grinding wheel 44 constituting the spindle unit 4 of the grinding unit 3. The chuck table moving means 8 shown in FIG. 4 for moving between them is provided. The chuck table moving means 8 shown in FIG. 4 includes a support base 81 that supports the spindle unit 7 and a pair of guide rails 82 and 82 that slidably support the support base 81. The pair of guide rails 82, 82 are arranged on the main portion 21 of the housing 2 in the direction indicated by the arrows 23 a and 23 b that are the front-rear direction (the direction perpendicular to the front surface of the upright wall 22). The support table 81 slidably mounted on the pair of guide rails 82 is connected to the workpiece mounting area indicated by the solid line in FIG. 4 (the workpiece mounting area 24 illustrated in FIG. 1) by the moving mechanism 83. ) And a grinding area indicated by a two-dot chain line in FIG. 4 (grinding area 25 shown in FIG. 1). The moving mechanism 83 includes a male screw rod 831 disposed between the pair of guide rails 82 and 82 and extending in parallel with the guide rails 82 and 82, and a servo motor 832 that rotationally drives the male screw rod 831. The male screw rod 831 is screwed into a screw hole 811 provided in the support base 81, and its tip is rotatably supported by a bearing member 833 attached by connecting a pair of guide rails 82 and 82. ing. The servo motor 832 has a drive shaft connected to the base end of the male screw rod 831 in a transmission manner. Therefore, when the servo motor 832 rotates in the forward direction, the support base 81, that is, the chuck table 61 moves in the direction indicated by the arrow 23a. When the servo motor 832 rotates in the reverse direction, the support base 81, that is, the chuck table 61 moves in the direction indicated by the arrow 23b. It is done.

The grinding apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
As shown in FIG. 1, a wafer W as a workpiece is placed on a holding surface which is an upper surface of a chuck table 61 positioned in a workpiece placement area 24 of a grinding apparatus. A protective tape T for protecting the device is attached to the surface on which the device is formed on the wafer W, and this protective tape T side is placed on the upper surface of the chuck table 61. When the wafer W as the workpiece is placed on the chuck table 61 in this way, the electromagnetic on-off valve 743 constituting the suction means 74 of the chuck table mechanism 6 shown in FIG. 3 is energized (ON). . As a result, as described above, the holding surface, which is the upper surface of the suction holding chuck 612, from the suction source 741 to the suction pipe 742, the passage 731 formed in the rotary joint 73, the communication passage 722, the suction passage 611c, and the fitting recess 611a. A negative pressure is applied to the wafer W, and the wafer W placed on the chuck table 61 via the protective tape T is sucked and held. When the wafer W is sucked and held on the chuck table 61 in this way, the moving mechanism 83 of the chuck table moving means 8 shown in FIG. 4 is operated to move the chuck table 62 in the direction indicated by the arrow 23a and perform grinding. Position in area 25.

  When the chuck table 61 is positioned in the grinding area 25 in this way, the electric motor 75 constituting the spindle unit 7 of the chuck table mechanism 6 is driven to rotate the rotary spindle 72 so that the chuck table 61 is moved in a predetermined direction, for example. While rotating at a rotational speed of 300 rpm, the electric motor 46 constituting the spindle unit 4 of the grinding unit 3 is driven to rotate the rotary spindle 42 and rotate the grinding wheel 44 in a predetermined direction, for example, at a rotational speed of 6000 rpm. At this time, the electromagnetic on-off valve 764 disposed in the radial bearing pipe 762 constituting the fluid supply means 76 of the chuck table mechanism 6 is energized (ON), and the inner periphery of the shaft hole 711 of the spindle housing 71 as described above. A fluid layer is formed between the surface and the outer peripheral surface of the rotary spindle 72 to rotatably support the rotary spindle 72, and electromagnetic on-off valves 765a, 765b respectively disposed in the thrust bearing pipes 763a, 763b, 763c, By energizing (ON) 765c, a fluid layer is formed between the upper and lower walls 715a and 715b of the plate accommodating chamber 715 and the thrust plate 721 as described above, and the thrust plate 721 accommodated in the plate accommodating chamber 715 is disposed. Fluid support in the axial direction. The support rigidity for fluidly supporting the thrust plate 721 is adjusted by the material forming the substrate of the wafer W that is the workpiece. For example, when the substrate of the wafer W is formed of sapphire, the electromagnetic on-off valves 765a and 765b constituting the fluid supply means 76 are energized (ON) and the high pressure fluid is platen through the thrust bearing pipes 763a and 763b. It flows into the storage chamber 714. On the other hand, when the substrate of the wafer W is formed of silicon carbide (SiC), the electromagnetic on-off valves 765a, 765b, 765c constituting the fluid supply means 76 are energized (ON) to provide thrust bearing piping 763a, The support rigidity is increased by allowing the high-pressure fluid to flow into the plate housing chamber 714 through 763b and 763c.

  Further, when the electric motor 46 constituting the spindle unit 4 of the grinding unit 3 is driven to rotate the rotating spindle 42 and rotate the grinding wheel 44, the radial bearing pipe 472 constituting the fluid supply means 47 of the grinding unit 3. As described above, the electromagnetic on-off valve 474 disposed in the shaft is turned on to form a fluid layer between the inner peripheral surface of the shaft hole 411 of the spindle housing 41 and the outer peripheral surface of the rotary spindle 42 and rotate. The spindle 42 is rotatably supported by the fluid, and the electromagnetic on-off valves 475a, 475b, 475c disposed in the thrust bearing pipes 473a, 473b, 473c are energized (ON) as described above. Thrust plate accommodated in the plate accommodation chamber 415 by forming a fluid layer between the upper wall 415a and the lower wall 415b and the thrust plate 421. 421 is fluidly supported in the axial direction. The support rigidity for fluidly supporting the thrust plate 421 is adjusted by the material forming the substrate of the wafer W that is the workpiece. For example, when the substrate of the wafer W is formed of sapphire, the electromagnetic on-off valves 475a and 475b constituting the fluid supply means 47 are energized (ON) and high pressure fluid is platen through the thrust bearing pipes 473a and 473b. It flows into the storage chamber 415. On the other hand, when the substrate of the wafer W is formed of silicon carbide (SiC), the electromagnetic on-off valves 475a, 475b, and 475c constituting the fluid supply means 47 are energized (ON), and the thrust bearing pipe 473a, The support rigidity is increased by allowing the high-pressure fluid to flow into the plate storage chamber 415 through 473b and 473c.

  The axial rigidity of the thrust plate 721 accommodated in the plate accommodating chamber 715 constituting the spindle unit 7 of the chuck table mechanism 6 and the thrust accommodated in the plate accommodating chamber 415 constituting the spindle unit 4 of the grinding unit 3 are described. Only one of the adjustments of the support rigidity in the axial direction of the plate 421 may be used. For example, in the chuck table mechanism 6, the electromagnetic on-off valves 765 a, 765 b, 765 c constituting the fluid supply means 76 are energized (ON) to allow high-pressure fluid to flow into the plate housing chamber 715 through the thrust bearing pipes 763 a, 763 b, 763 c. As a result, the supporting rigidity of the thrust plate 721 is maintained to be increased, and the electromagnetic on-off valves 475a and 475b constituting the fluid supply means 47 corresponding to the material forming the substrate of the wafer W that is the workpiece in the grinding unit 3 The support rigidity of the thrust plate 421 may be adjusted by selecting 475c and energizing (ON). In the grinding unit 3, the electromagnetic on-off valves 475 a, 475 b and 475 c constituting the fluid supply means 47 are energized (ON) to allow high-pressure fluid to flow into the plate housing chamber 415 through the thrust bearing pipes 473 a, 473 b and 473 c. The thrust plate 421 is maintained in a state where the rigidity of the thrust plate 421 is increased, and the electromagnetic on-off valves 765a, 765b, 765c constituting the fluid supply means 76 are selected and energized (ON) in the chuck table mechanism 6 to thereby activate the thrust plate 721. You may adjust the support rigidity of.

  As described above, the support rigidity with respect to the axial direction of the thrust plate 421 accommodated in the plate accommodation chamber 415 constituting the spindle unit 4 of the grinding unit 3 or the plate accommodation chamber 715 constituting the spindle unit 7 of the chuck table mechanism 6 is accommodated. If the support rigidity in the axial direction of the thrust plate 721 or the support rigidity in the axial direction of the thrust plate 421 and the thrust plate 721 is adjusted in accordance with the material forming the substrate of the wafer W as the workpiece, the grinding feed The pulse motor 54 of the means 5 is driven to rotate forward to lower the grinding unit 3, and the grinding surfaces of the grinding wheels 442 of the grinding wheel 44 are brought into contact with the upper surface (back surface) of the wafer W held on the chuck table 61. Feed fixed grinding. As a result, the wafer W held on the chuck table 61 is ground to a predetermined thickness. At this time, as described above, the rigidity of the axial support of the thrust plate 421 accommodated in the plate accommodation chamber 415 constituting the spindle unit 4 of the grinding unit 3 or the plate accommodation chamber 715 constituting the spindle unit 7 of the chuck table mechanism 6. Since the support rigidity in the axial direction of the thrust plate 721 or the support rigidity in the axial direction of the thrust plate 421 and the thrust plate 721 is adjusted according to the material forming the substrate of the wafer W as the workpiece. The wafer W held on the chuck table 61 is ground well.

  As mentioned above, although this invention was demonstrated based on embodiment of illustration, this invention is not limited only to embodiment, A various deformation | transformation is possible in the range of the meaning of this invention. For example, in the illustrated embodiment, the bearing mechanism of the rotating spindle 42 constituting the spindle unit 4 of the grinding unit 3 and the bearing mechanism of the rotating spindle 72 constituting the spindle unit 7 of the chuck table mechanism 6 are each constituted by a fluid bearing mechanism. However, only one of them may be configured by the hydrodynamic bearing mechanism according to the present invention.

1 is a perspective view of a grinding apparatus constructed according to the present invention. Sectional drawing of the spindle unit which comprises the grinding unit with which the grinding apparatus shown in FIG. 1 is equipped. The principal part perspective view of the chuck table mechanism with which the grinding apparatus shown in FIG. 1 is equipped. FIG. 2 is a cross-sectional view of a main part of a chuck table mechanism installed in the grinding apparatus shown in FIG. 1.

Explanation of symbols

2: Device housing 3: Grinding unit 31: Moving base 4: Spindle unit of grinding unit 41: Spindle housing 415: Plate housing chamber 42: Rotating spindle 421: Thrust plate 43: Wheel mount 44: Grinding wheel 46: Electric motor 47 : Fluid supply means 471: Fluid supply means 472: High pressure fluid source 473: Radial bearing piping 474: Electromagnetic on-off valves 475a, 475b, 475c: Electromagnetic on-off valves 5: Grinding feed means 6: Chuck table mechanism 61: Chuck table 7: Chuck Spindle unit of table mechanism 71: Spindle housing 715: Plate housing chamber 72: Rotating spindle 721: Thrust plate 73: Rotary joint 74: Suction means 741: Suction source 742: Suction pipe 743: Electromagnetic switching Valve 75: Electric motor 76: Fluid supply means 761: Fluid supply means 762: High-pressure fluid source 763: Radial bearing piping 764: Electromagnetic on-off valves 765a, 765b, 765c: Electromagnetic on-off valves

Claims (5)

A chuck table mechanism having a chuck table having a holding surface for holding a workpiece, a grinding means for grinding the workpiece held on the holding surface of the chuck table, and the grinding means for the chuck table A grinding apparatus comprising a grinding feed means for grinding and feeding in a direction perpendicular to the holding surface of
The grinding means includes a rotary spindle provided with a thrust plate on the outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, a plate storage space for storing the thrust plate, and the plate storage A spindle housing having a thrust bearing portion having a plurality of fluid supply holes respectively opening in a plurality of regions of the space, a wheel mount provided at the lower end of the rotary spindle, and a grinding wheel attached to the wheel mount; Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber of the plate storage chamber through the plurality of fluid supply holes of the radial bearing portion and the thrust bearing portion;
The fluid supply means includes support stiffness adjusting means for adjusting a support stiffness of the thrust plate by adjusting a supply region of fluid supplied to the plate housing chamber through the plurality of fluid supply holes.
A grinding apparatus characterized by that.   The grinding apparatus according to claim 1, wherein the support rigidity adjusting means includes selection means for selecting a fluid to be supplied to the plurality of fluid supply holes. A chuck table mechanism having a chuck table having a holding surface for holding a workpiece, a grinding means for grinding the workpiece held on the holding surface of the chuck table, and the grinding means for the chuck table A grinding apparatus comprising a grinding feed means for grinding and feeding in a direction perpendicular to the holding surface of
The chuck table mechanism includes a rotary spindle having an upper end coupled to the chuck table and a thrust plate provided on an outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, and the thrust plate. A spindle housing having a thrust housing portion having a plate housing space to be accommodated and a plurality of fluid supply holes that open to a plurality of regions of the plate housing space, the radial bearing portion, and the plurality of fluid supplies of the thrust bearing portion Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber through holes;
The fluid supply means includes support stiffness adjusting means for adjusting a support stiffness of the thrust plate by adjusting a supply region of fluid supplied to the plate housing chamber through the plurality of fluid supply holes.
A grinding apparatus characterized by that.   The grinding apparatus according to claim 3, wherein the support rigidity adjusting means includes selection means for selecting a fluid to be supplied to the plurality of fluid supply holes. A chuck table mechanism having a chuck table having a holding surface for holding a workpiece, a grinding means for grinding the workpiece held on the holding surface of the chuck table, and the grinding means for the chuck table A grinding apparatus comprising a grinding feed means for grinding and feeding in a direction perpendicular to the holding surface of
The grinding means includes a rotary spindle provided with a thrust plate on the outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, a plate storage space for storing the thrust plate, and the plate storage A spindle housing having a thrust bearing portion having a plurality of fluid supply holes respectively opening in a plurality of regions of the space, a wheel mount provided at the lower end of the rotary spindle, and a grinding wheel attached to the wheel mount; Fluid supply means for supplying fluid to the plurality of regions of the plate housing chamber through the plurality of fluid supply holes of the radial bearing portion and the thrust bearing portion is provided, and the fluid supply means passes through the plurality of fluid supply holes. Adjusting the supply area of the fluid supplied to the plate storage chamber and adjusting the support rigidity of the thrust plate Comprises a supporting rigidity adjusting means that,
The chuck table mechanism includes a rotary spindle having an upper end coupled to the chuck table and a thrust plate provided on an outer peripheral surface, a radial bearing portion that forms a fluid layer around the rotary spindle and supports the fluid, and the thrust plate. A spindle housing having a thrust housing portion having a plate housing space to be accommodated and a plurality of fluid supply holes that open to a plurality of regions of the plate housing space, the radial bearing portion, and the plurality of fluid supplies of the thrust bearing portion Fluid supply means for supplying fluid to the plurality of regions of the plate storage chamber through holes, the fluid supply means adjusting the supply region of fluid supplied to the plate storage chamber through the plurality of fluid supply holes; A support stiffness adjusting means for adjusting the support stiffness of the thrust plate is provided.
A grinding apparatus characterized by that.

Images