Processing equipment

Abstract

To provide a processing device that can remove processed chips adhering to irregularities on a holding surface of a porous plate.SOLUTION: A processing device 1 comprises: a porous chuck table 41 that holds by suction a work-piece, with a holding surface 46 made of a porous plate 42; a grinding unit that processes the work-piece held on the porous chuck table 41; a washing unit 70 that washes the holding surface 46 of the porous chuck table 41; and a control part. The washing unit 70 has: a main body part 71 which comprises a vibrating part 72 having a piezoelectric element and a nozzle hole 81 that supplies liquid 89 for transmitting vibrations of the vibrating part 72; and a positioning unit that positions the main body part 71 at a washing position where an end face 78 of the vibrating part 72 faces the holding surface 46 of the porous plate 42 through a gap with a predetermined width and a retreat position retreating from the porous chuck table 41.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a processing apparatus including a cleaning unit for a porous chuck table.

Background Art

[0002] In a processing apparatus for grinding, polishing, cutting, etc. various plate-shaped workpieces such as semiconductor device wafers, ceramic substrates, resin package substrates, etc., the workpiece is sucked and held by a porous chuck table and processed. The porous chuck table includes a porous plate such as ceramics, and on the holding surface of the polished and flattened porous plate, the workpiece can be sucked as a whole (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the workpiece is ground, polished, cut, etc. while being sucked and held by the porous plate, the machining chips generated during processing are sucked by the porous plate, and the machining chips are likely to remain on the porous plate. The remaining machining chips may adhere to the workpiece or cause a decrease in the air permeability of the porous plate. Therefore, the holding surface of the porous chuck table is cleaned with water, air, a brush, etc., but it is difficult to remove the unevenness on the holding surface of the porous plate and the machining chips attached to the inside.

[0005] An object of the present invention is to provide a processing apparatus capable of removing machining chips adhering to the unevenness of the holding surface of a porous plate.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a processing apparatus of the present invention is a processing apparatus that holds and processes a workpiece with a porous chuck table, and sucks and holds the workpiece with a holding surface made of a porous plate. A porous chuck table, a processing unit that processes the workpiece held by the porous chuck table, a cleaning unit that cleans the holding surface of the porous chuck table, and a control unit that controls each component. The cleaning unit includes a vibration unit having a piezoelectric element, and a nozzle that supplies a liquid that propagates the vibration of the vibration unit. A positioning unit that positions the main body at a cleaning position where an end surface of the vibration unit faces the holding surface of the porous plate with a gap of a predetermined value or less, and a retracted position where the main body is retracted from the porous chuck table. The porous chuck table is configured to be rotatable about a rotation axis orthogonal to the holding surface, The control unit positions the main body at the cleaning position, and vibrates the vibration unit while supplying the liquid from the nozzle into the gap between the end surface of the vibration unit and the holding surface. and while rotating the porous chuck table, the body portion is moved in the radial direction of the holding surface while maintaining the cleaning position with the positioning unit, and the holding surface is cleaned with the end surface of the vibrating portion having a smaller diameter than the holding surface, It is characterized by cleaning the holding surface to which machining chips adhere.

[0007] In the processing apparatus, the porous chuck table includes a fluid supply unit that supplies fluid to the porous plate and ejects fluid from the holding surface. The control unit may operate the fluid supply unit to eject fluid from the holding surface while cleaning the holding surface with the cleaning unit.

[0009] In the processing apparatus, the processing unit may be a grinding and polishing unit to which a tool for grinding or polishing a workpiece is attached.

Effects of the Invention

[0010] The present invention has an effect of being able to remove machining chips adhering to the unevenness of the holding surface of a porous plate.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0012] A mode (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the content described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Also, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[0013] 〔Embodiment 1〕 The processing apparatus 1 according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration example of the processing apparatus according to Embodiment 1. FIG. 2 is a cross-sectional view schematically showing the configuration of the porous chuck table of the processing apparatus shown in FIG. 1. FIG. 3 is a view schematically showing the configuration of the main body portion and the like of the cleaning unit of the processing apparatus shown in FIG. 1. FIG. 4 is a plan view of the main body portion shown in FIG. 3 as viewed from below.

[0014] (Processing apparatus) In Embodiment 1, the processing apparatus 1 is a grinding apparatus that grinds (equivalent to processing) the workpiece 200. The workpiece 200 to be processed by the processing apparatus 1 shown in FIG. 1 is a wafer such as a disk-shaped semiconductor wafer or an optical device wafer based on a substrate such as silicon, sapphire, or gallium. In the workpiece 200, devices 203 are formed in each region partitioned by division planned lines 202 formed in a grid pattern on the surface 201 of the substrate.

[0015] The device 203 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), or a MEMS (Micro Electro Mechanical Systems).

[0016] Also, in Embodiment 1, after the protective tape 205 is adhered to the surface 201 of the workpiece 200 and the back surface 204 on the back side of the surface 201 is ground by the processing apparatus 1 and thinned to a predetermined finish thickness, the workpiece 200 is divided into individual devices 203 along the division planned lines 202. Further, in the present invention, the workpiece 200 is not limited to a wafer, and may be a rectangular package substrate having a plurality of devices sealed with resin, a ceramic substrate, a glass substrate, a ferrite substrate, or a substrate containing at least one of nickel and iron.

[0017] The processing apparatus 1 shown in FIG. 1 is a grinding apparatus that holds the surface 201 of the workpiece 200 on the porous chuck table 41 via the protective tape 205, grinds the back surface 204 of the workpiece 200, and thins the workpiece 200 to a predetermined finish thickness. As shown in FIG. 1, the processing apparatus 1 includes an apparatus main body 2, a first grinding unit 10, a second grinding unit 20, a grinding feed unit 30, a turntable 40, a plurality (three in Embodiment 1) of porous chuck tables 41 installed on the turntable 40, a cassette 60, an alignment unit 61, a loading unit 62, an unloading unit 63, a workpiece cleaning unit 64, a loading / unloading unit 65, a cleaning unit 70, and a control unit 100.

[0018] The turntable 40 is a disk-shaped table provided on the upper surface of the apparatus main body 2, is rotatably provided around an axis parallel to the Z-axis direction in the horizontal plane, and is rotationally driven at a predetermined timing. On this turntable 40, for example, three porous chuck tables 41 are arranged at equal intervals with a phase angle of, for example, 120 degrees.

[0019] These three porous chuck tables 41 suck and hold the workpiece 200 on the holding surface 46 made of a porous plate 42. As shown in FIG. 2, the porous chuck table 41 includes a disk-shaped porous plate 42, a thick disk-shaped base 43 that supports the outer edge of the porous plate 42, a suction unit 44, and a fluid supply unit 45.

[0020] The porous plate 42 is made of a porous material such as porous ceramics and has air permeability. The upper surface of the porous plate 42 is the holding surface 46 for holding the workpiece 200. For this purpose, minute irregularities are formed on the holding surface 46 of the porous plate 42. The base 43 is made of dense ceramics or the like, and a recess 48 for attaching the porous plate 42 is provided at the center of the upper surface 47. When the porous plate 42 is attached in the recess 48 of the base 43, the upper surface 47 is located in the same plane as the holding surface 46.

[0021] The suction unit 44 sucks the holding surface 46. The suction unit 44 includes a suction source 49, a suction passage 50 connecting the suction source 49 and the bottom surface of the recess 48 of the base 43, and an on-off valve 51 provided in the suction passage 50. The suction unit 44 sucks the holding surface 46 when the on-off valve 51 opens and the suction source 49 sucks the suction passage 50.

[0022] The fluid supply unit 45 supplies fluid to the porous plate 42 and ejects the fluid from the holding surface 46. The fluid supply unit 45 includes a fluid source 52 that supplies fluid, a fluid supply passage 53 connecting the fluid source 52 and the bottom surface of the recess 48 of the base 43, and an on-off valve 54 provided in the fluid supply passage 53. The fluid supply unit 45 ejects the fluid from the holding surface 46 when the on-off valve 54 opens and the fluid source 52 supplies fluid to the porous plate 42 through the fluid supply passage 53. In the first embodiment, the fluid supply unit 45 supplies pure water as the fluid to the porous plate 42 and ejects it from the holding surface 46. However, in the present invention, the fluid is not limited to pure water.

[0023] In the porous chuck table 41 having the above-described configuration, the surface 201 side of the workpiece 200 is placed on the holding surface 46 via the protective tape 205, and the holding surface 46 is sucked by the suction source 49, so that the workpiece 200 is sucked and held on the holding surface 46.

[0024] Further, these porous chuck tables 41 are configured to be rotatable about a rotation axis 55 parallel to the Z-axis direction (vertical direction) in which the base 43 is orthogonal to the holding surface 46. During grinding, the porous chuck table 41 is rotationally driven in the horizontal plane by a rotation drive mechanism 56 about the rotation axis 55. The porous chuck table 41 is sequentially moved to the loading / unloading area 301, rough grinding area 302, finish grinding area 303, and loading / unloading area 301 by the rotation of the turntable 40.

[0025] The loading / unloading area 301 is an area for loading and unloading the workpiece 200 onto and from the porous chuck table 41. The rough grinding area 302 is an area for rough grinding (equivalent to grinding) the workpiece 200 held on the porous chuck table 41 by the first grinding unit 10. The finish grinding area 303 is an area for finish grinding (equivalent to grinding) the workpiece 200 held on the porous chuck table 41 by the second grinding unit 20.

[0026] The first grinding unit 10 is a grinding and polishing unit (equivalent to a processing unit) in which a grinding wheel 12 for rough grinding, which is provided with a rough grinding abrasive stone 11 arranged in a ring shape for rough grinding the back surface 204 exposed above the workpiece 200 held on the porous chuck table 41, is mounted at the lower end of the spindle, and the back surface 204 of the workpiece 200 held on the holding surface 46 of the porous chuck table 41 in the rough grinding area 302 is rough ground. The second grinding unit 20 is a grinding and polishing unit (equivalent to a processing unit) in which a grinding wheel 22 for finish grinding, which is provided with a finish grinding abrasive stone 21 arranged in a ring shape for finish grinding the back surface 204 of the workpiece 200 held on the porous chuck table 41, is mounted at the lower end of the spindle, and the back surface 204 of the workpiece 200 held on the holding surface 46 of the porous chuck table 41 in the finish grinding area 303 is finish ground.

[0027] The grinding units 10 and 20 rotate the grinding wheels 12 and 22 around the axis by motors 13 and 23, supply grinding water to the back surface 204 of the workpiece 200 held on the porous chuck table 41 in the grinding areas 302 and 303, and move the abrasive stones 11 and 21 closer to the porous chuck table 41 at a predetermined feed rate by the grinding feed unit 30, thereby rough grinding or finish grinding the back surface 204 of the workpiece 200.

[0028] The grinding feed unit 30 moves the grinding units 10 and 20 in the Z-axis direction to move the grinding units 10 and 20 away from and closer to the porous chuck table 41. In Embodiment 1, the grinding feed unit 30 is provided on a standing column 3 erected from one end in the Y-axis direction parallel to the horizontal direction of the apparatus main body 2. The grinding feed unit 30 includes a well-known ball screw rotatably provided around its axis, a well-known motor for rotating the ball screw around its axis, and a well-known guide rail for movably supporting the spindle housings of the grinding units 10 and 20 in the Z-axis direction.

[0029] In addition, in Embodiment 1, the axis of the first grinding unit 10 and the axis of the second grinding unit 20, which are the rotation centers of the grinding wheels 12 and 22, and the axis of the porous chuck table 41, which is the rotation center of the porous chuck table 41, are arranged parallel to each other with a horizontal interval therebetween, and the grinding wheels 11 and 21 pass over the center of the back surface 204 of the workpiece 200 held by the porous chuck table 41.

[0030] The cassette 60 is a storage container having a plurality of slots for storing a plurality of workpieces 200. The cassette 60 stores a plurality of workpieces 200 before and after grinding. In Embodiment 1, a pair of cassettes 60 are provided and are respectively installed on cassette installation tables. The cassette installation table raises and lowers the cassette 60 in the Z-axis direction. The alignment unit 61 is a table for temporarily placing the workpiece 200 taken out from the cassette 60 and performing centering thereof.

[0031] The loading unit 62 and the unloading unit 63 have suction pads for sucking the workpiece 200. The loading unit 62 sucks and holds the workpiece 200 before grinding that has been aligned by the alignment unit 61, and loads it onto the holding surface 46 of the porous chuck table 41 located in the loading / unloading area 301. The unloading unit 63 sucks and holds the workpiece 200 after grinding on the holding surface 46 of the porous chuck table 41 located in the loading / unloading area 301, and conveys the workpiece 200 to the workpiece cleaning unit 64. The workpiece cleaning unit 64 cleans the workpiece 200 after grinding, and removes contaminations such as grinding chips (corresponding to processed chips) adhering to the ground back surface 204.

[0032] The loading / unloading unit 65 takes out the workpiece 200 before grinding from the cassette 60, conveys the workpiece 200 to the alignment unit 61, takes out the workpiece 200 after grinding from the workpiece cleaning unit 64, and conveys it to the cassette 60. The loading / unloading unit 65 is a robot pick having, for example, a U-shaped hand 66, and sucks and holds the workpiece 200 by the U-shaped hand 66 and conveys it.

[0033] The cleaning unit 70 cleans the holding surface 46 of the porous chuck table 41. The cleaning unit 70 is installed above the porous chuck table 41 located in the loading / unloading area 301, and has a main body 71 and a positioning unit 90 shown in FIG. 3.

[0034] As shown in FIG. 3, the main body 71 includes a vibration unit 72 and a nozzle 81. The vibration unit 72 has a piezoelectric element 73, a mounting member 74 attached to the piezoelectric element 73, and a vibration member 75 attached to the lower end of the mounting member 74.

[0035] The piezoelectric element 73 is powered by a power source (not shown) and, in Embodiment 1, expands and contracts (also referred to as vibration and hereinafter referred to as ultrasonic vibration) in the Z-axis direction at a frequency of 10 kHz or more and 60 kHz or less with an amplitude of 3 μm to 50 μm. In Embodiment 1, the piezoelectric element 73 is formed in a thick disk shape with an outer diameter smaller than that of the workpiece 200.

[0036] The mounting member 74 is made of a metal such as stainless steel and is formed in a cylindrical shape with the piezoelectric element 73 attached to the upper end and the vibrating member 75 attached to the lower end. In Embodiment 1, the mounting member 74 includes a large-diameter portion 76 with an outer diameter equal to that of the piezoelectric element 73 and the piezoelectric element 73 attached to the upper end, and a small-diameter portion 77 connected to the lower end of the large-diameter portion 76 with an outer diameter smaller than that of the piezoelectric element 73 and the vibrating member 75 attached to the lower end. The mounting member 74 arranges the large-diameter portion 76 and the small-diameter portion 77 coaxially with each other. The length, diameter, and material of the mounting member 74 are selected such that the vibration of the piezoelectric element 73 is transmitted to the vibrating member 75 most efficiently without attenuation.

[0037] The vibrating member 75 is attached to the lower end of the mounting member 74 and has an end face 78 facing the holding surface 46 of the porous chuck table 41 located in the loading / unloading area 301 along the Z-axis direction. The end face 78 of the vibrating member 75 is formed flat along the X-axis direction parallel to the horizontal direction and the Y-axis direction orthogonal to the X-axis direction and parallel to the horizontal direction. In Embodiment 1, the outer diameter of the vibrating member 75 is 5 mm or more and 30 mm or less.

[0038] Also, in Embodiment 1, a cylindrical second mounting member 79 having the same diameter as the piezoelectric element 73 is attached to the upper surface of the piezoelectric element 73 in the main body portion 71. The second mounting member 79, the piezoelectric element 73, and the large-diameter portion 76 of the mounting member 74 are housed in a cylindrical member 80 made of metal or the like, and the piezoelectric element 73 is pressed and fixed to the mounting member 74.

[0039] The vibrating part 72 is powered by a power source to supply power to the piezoelectric element 73, causing the piezoelectric element 73 to ultrasonically vibrate. The ultrasonic vibration of the piezoelectric element 73 is propagated to the vibrating member 75 through the mounting member 74, and the end face 78 of the vibrating member 75 ultrasonically vibrates along the Z-axis direction.

[0040] The nozzle 81 supplies a liquid 89 (shown in FIG. 5) that propagates the ultrasonic vibration of the vibrating part 72 between the end face 78 of the vibrating member 75 and the holding surface 46 of the porous chuck table 41. The nozzle 81 includes a cylindrical nozzle member 82 with an inner diameter larger than the outer diameters of the vibrating member 75 and the small-diameter part 77, a liquid supply path 84 that supplies the liquid 89 from the liquid supply source 83 into the nozzle member 82, and an on-off valve 85 provided in the liquid supply path 84.

[0041] The nozzle member 82 houses the vibrating member 75 and the small-diameter part 77 inside, has its upper end attached to the lower end of the large-diameter part 76 and the cylindrical member 80, and is arranged at a position coaxial with the vibrating member 75 and the small-diameter part 77. The lower end of the nozzle member 82 is formed in a plane along both the X-axis direction and the Y-axis direction, and the lower end is arranged on the same plane as the end face 78 of the vibrating member 75.

[0042] The liquid supply path 84 is a cylindrical member that allows the liquid 89 to pass through inside, such as a tube. It includes a single supply source connection part 86 connected to the liquid supply path 84, and a plurality (two in Embodiment 1) of nozzle connection parts 87 connected to the supply source connection part 86 and the through hole 88 that penetrates the nozzle member 82 as shown in FIG. 4. The on-off valve 85 is provided at the supply source connection part 86 of the liquid supply path 84.

[0043] When the on-off valve 85 of the nozzle 81 opens, the liquid 89 from the liquid supply source 83 is supplied into the inside of the nozzle member 82 through the liquid supply path 84, and the liquid 89 is supplied onto the holding surface 46 of the porous chuck table 41 from the lower end of the nozzle member 82. In Embodiment 1, the nozzle 81 supplies pure water as the liquid 89.

[0044] The positioning unit 90 positions the main body 71 at a cleaning position shown in Fig. 5 where the end face 78 of the vibrating unit 72 faces the holding surface 46 of the porous plate 42 of the porous chuck table 41 with a gap of not more than a predetermined value, and at a retracted position where the end face 78 of the vibrating unit 72 is retracted from the porous chuck table 41. The cleaning position is a position of the main body 71 where the end face 78 of the vibrating unit 72 faces the holding surface 46 with a space therebetween, and the end face 78 of the vibrating unit 72 is immersed in the liquid 89 supplied from the nozzle 81 to the holding surface 46 of the porous chuck table 41.

[0045] In Embodiment 1, the positioning unit 90 moves the main body 71 up and down along the Z-axis direction and also moves horizontally above the porous plate 42 of the porous chuck table 41 located in the loading / unloading area 301. In Embodiment 1, when the positioning unit 90 moves the main body 71 horizontally, it passes above the center of the holding surface 46 of the porous plate 42 of the porous chuck table 41 located in the loading / unloading area 301. The positioning unit 90 includes a well-known ball screw, a well-known motor, a well-known guide rail, and the like.

[0046] The control unit 100 controls each of the above-described components constituting the processing apparatus 1. That is, the control unit 100 causes the processing apparatus 1 to execute a processing operation on the workpiece 200. The control unit 100 is a computer having an arithmetic processing unit with a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and an input / output interface device.

[0047] The arithmetic processing unit of the control unit 100 performs arithmetic processing according to a computer program stored in a storage device, and outputs a control signal for controlling the processing device 1 to the above-described components of the processing device 1 via an input / output interface device. Further, the control unit 100 is connected to a display unit composed of, for example, a liquid crystal display device that displays the state and image of the processing operation, an input unit used when an operator registers processing content information, etc., and a notification unit that notifies the operator. The input unit is composed of at least one of a touch panel provided on the display unit and a keyboard or the like. The notification unit notifies the operator by emitting at least one of sound, light, and a message on the touch panel.

[0048] Next, the processing operation of the processing device 1 according to Embodiment 1 will be described. In the processing device 1, a cassette 60 containing a workpiece 200 with a protective tape 205 before grinding attached thereto is installed on a cassette installation table, and the processing conditions are registered in the control unit 100 by an operator. When the control unit 100 of the processing device 1 receives an instruction to start the processing operation from the operator, it starts the processing operation.

[0049] In the processing operation, the control unit 100 of the processing device 1 causes the carry-in / out unit 65 to take out the workpiece 200 from the cassette 60 and carry it out to the alignment unit 61. The control unit 100 causes the alignment unit 61 to perform centering of the workpiece 200, and carries the surface 201 side of the aligned workpiece 200 into the holding surface 46 of the porous chuck table 41 located in the carry-in / out region 301 by the carry-in unit 62.

[0050] The control unit 100 of the processing apparatus 1 sucks and holds the surface 201 side of the workpiece 200 on the holding surface 46 of the porous chuck table 41 in the loading / unloading area 301 via the protective tape 205, exposes the back surface 204, and conveys the workpiece 200 in order to the rough grinding area 302, the finish grinding area 303, and the loading / unloading area 301 by the turntable 40, and performs rough grinding and finish grinding in order. Note that the control unit 100 of the processing apparatus 1 loads the workpiece 200 before grinding into the porous chuck table 41 in the loading / unloading area 301 every time the turntable 40 rotates 120 degrees.

[0051] The control unit 100 of the processing apparatus 1 loads the workpiece 200 after grinding into the workpiece cleaning unit 64 by the unloading unit 63, cleans it in the workpiece cleaning unit 64, and loads the workpiece 200 after cleaning into the cassette 60 by the U-shaped hand 66 of the loading / unloading unit 65. The control unit 100 of the processing apparatus 1 ends the processing operation when grinding is performed on all the workpieces 200 in the cassette 60. In the above-described processing operation, the control unit 100 of the processing apparatus 1 controls the positioning unit 90 of the cleaning unit 70 to position the main body 71 of the cleaning unit 70 at the retracted position. Further, the processing apparatus 1 generates machining chips during rough grinding and finish grinding, and a part of the machining chips generated during the processing operation may adhere to the holding surface 46 of the porous chuck table 41.

[0052] Next, a cleaning operation for cleaning the holding surface 46 of the porous chuck table 41 of the cleaning unit 70 of the processing apparatus 1 according to Embodiment 1 will be described. FIG. 5 is a cross-sectional view for explaining the cleaning operation of the cleaning unit shown in FIG. 3. FIG. 6 is a cross-sectional view for explaining the movement range of the main body in the cleaning operation of the cleaning unit shown in FIG. 3. FIG. 7 is a plan view for explaining the movement range of the main body in the cleaning operation of the cleaning unit shown in FIG. 3.

[0053] When the control unit 100 determines that it is a predetermined timing, the processing apparatus 1 starts the cleaning operation of the holding surface 46 of the porous chuck table 41. The predetermined timing is any timing for cleaning the holding surface 46 of the porous chuck table 41. For example, every time each workpiece 200 before grinding is carried into the porous chuck table 41 located in the loading / unloading area 301 during the processing operation, when a predetermined number of workpieces 200 before grinding are carried into the porous chuck table 41 located in the loading / unloading area 301, after each workpiece 200 after grinding is carried out from the porous chuck table 41 located in the loading / unloading area 301 after the processing operation is completed, when an instruction to start the cleaning operation of the holding surface 46 of the porous chuck table 41 of the operator is received via the input unit or the like, and the like.

[0054] In the cleaning operation, the processing apparatus 1 positions the porous chuck table 41 to be cleaned in the loading / unloading area 301 by the control unit 100, closes the on-off valve 51 of the suction unit 44 of the porous chuck table 41 located in the loading / unloading area 301, and positions the main body 71 of the cleaning unit 70 at the cleaning position. In the cleaning operation, the processing apparatus 1 supplies the liquid 89 from the nozzle 81 into the gap between the end face 78 of the vibrating unit 72 and the holding surface 46 of the porous chuck table 41 located in the loading / unloading area 301 while the control unit 100 opens the on-off valve 85, opens the on-off valve 54 to operate the fluid supply unit 45 of the porous chuck table 41 located in the loading / unloading area 301, ejects the fluid from the holding surface 46 of the porous chuck table 41 located in the loading / unloading area 301, and supplies power to the piezoelectric element 73 of the vibrating unit 72 to ultrasonically vibrate the end face 78 of the vibrating unit 72 as shown in FIG. 5.

[0055] In the cleaning operation, since the end face 78 of the vibrating unit 72 is immersed in the liquid 89, the processing apparatus 1 applies ultrasonic vibration to the liquid 89 between the end face 78 and the holding surface by ultrasonically vibrating the end face 78 of the vibrating unit 72. In the cleaning operation, the processing apparatus 1 causes the machining chips attached to the holding surface 46 having minute irregularities to float from the holding surface 46 by the ultrasonic vibration of the liquid 89, and cleans the holding surface 46 to which the machining chips are attached.

[0056] Also, in the cleaning operation, the processing apparatus 1 supplies the liquid 89 from the nozzle 81 to the holding surface 46 of the porous chuck table 41 positioned in the loading / unloading area 301, ejects the fluid from the holding surface 46 of the porous chuck table 41 positioned in the loading / unloading area 301, rotates the porous chuck table 41 positioned in the loading / unloading area 301 around the rotation axis 55 while ultrasonically vibrating the end face 78 of the vibration unit 72, and moves the main body 71 in the radial direction of the holding surface 46 of the porous chuck table 41 between the position indicated by the solid line in FIGS. 6 and 7 located above one end of the holding surface 46 of the porous chuck table 41 and the position indicated by the two-dot chain line in FIGS. 6 and 7 located above the other end of the holding surface 46 of the porous chuck table 41.

[0057] Also, in the cleaning operation, since the fluid supplied from the fluid supply unit 45 is ejected from the holding surface 46, it promotes the floating of the processing chips from the holding surface 46 and ejects the processing chips attached inside the porous plate 42 from the holding surface 46 together with the fluid. Thus, the control unit 100 operates the fluid supply unit 45 to eject the fluid from the holding surface 46 while the cleaning unit 70 is cleaning the holding surface 46.

[0058] Also, in the processing operation, since the processing apparatus 1 rotates the porous chuck table 41 around the rotation axis 55 and moves the main body 71 between the position indicated by the solid line in FIGS. 6 and 7 and the position indicated by the two-dot chain line in FIGS. 6 and 7, the control unit 100 moves the main body 71 in the radial direction of the holding surface 46 while rotating the porous chuck table 41 and maintaining the cleaning position with the positioning unit 90, and cleans the holding surface 46 with the end face 78 of the vibration unit 72 having a diameter smaller than that of the holding surface 46.

[0059] In the first embodiment, in the cleaning operation, the frequency of the ultrasonic vibration of the piezoelectric element 73 is set to 10 kHz or more and 60 kHz or less, the amplitude of the ultrasonic vibration of the piezoelectric element 73 is set to 3 μm or more and 50 μm or less, the distance between the end face 78 and the holding surface 46 is set to 0.5 mm or more and 5 mm or less, and the flow rate of the liquid 89 supplied from the nozzle 81 is set to 0.3 l / min or more and 2.0 l / min or less.

[0060] As described above, the processing apparatus 1 according to Embodiment 1 positions the liquid 89 between the holding surface 46 of the porous plate 42 and the end surface 78 of the vibrating portion 72 facing the holding surface 46, and immerses the end surface 78 in the liquid 89, so that ultrasonic vibration can be propagated to the holding surface 46 with little attenuation. As a result, the processing apparatus 1 according to Embodiment 1 can lift and wash the machining chips adhering to the unevenness of the holding surface 46 of the porous plate 42 that cannot be reached by brushing or water injection, and has the effect of being able to remove the machining chips adhering to the unevenness of the holding surface 46 of the porous plate 42.

[0061] Further, even if the vibrating portion 72 is formed small for easy ultrasonic vibration, the processing apparatus 1 relatively moves the vibrating portion 72 and the porous chuck table 41, so that the entire holding surface 46 can be efficiently cleaned.

[0062] Further, the processing apparatus 1 can promote the floating of the machining chips by ejecting a fluid from the holding surface 46 during cleaning, and can also suppress the intrusion of the machining chips into the porous plate 42.

[0063] Note that the present invention is not limited to the above-described embodiment. That is, various modifications can be made and implemented without departing from the gist of the present invention. In Embodiment 1, the grinding wheels 12 and 22 are attached to the lower ends of the spindles of the grinding units 10 and 20 of the processing apparatus 1. However, in the present invention, as shown in FIG. 8, a polishing tool 112 having a polishing pad 111 for polishing the workpiece 200 (corresponding to a tool for polishing the workpiece 200) is attached to the lower end of the spindle of the grinding units 10 and 20. Note that FIG. 8 is a perspective view showing a state in which a polishing tool is attached to the grinding unit of the processing apparatus shown in FIG. 1, and the same parts as those in Embodiment 1 are denoted by the same reference numerals and the description thereof is omitted.

[0064] In the present invention, when the polishing tool 112 is attached to the lower ends of the spindles of the grinding units 10 and 20, the processing apparatus 1 may polish the workpiece 200 while supplying a polishing liquid, may polish the workpiece 200 without supplying a polishing liquid (so-called dry polishing), or may polish the workpiece 200 while supplying a polishing liquid having a chemical action (so-called chemical mechanical polishing (CMP)).

[0065] In addition to the above-described embodiment, the porous chuck table 41 may be a universal chuck table that can hold workpieces having different diameters and has a barrier region made of a non-porous member on the holding surface 46 in a region corresponding to the outer periphery of the workpiece of each diameter. In particular, when the universal chuck table grinds or polishes a workpiece having a small diameter, machining chips are likely to adhere to the holding surface (region for sucking a workpiece having a large diameter) 46 exposed outside the workpiece having a small diameter. Therefore, the cleaning effect by the cleaning unit 70 of the present invention is great.

[0066] In the present invention, the processing apparatus 1 is not limited to the grinding apparatus described in the embodiment, and may be various processing apparatuses such as a cutting apparatus that holds the workpiece 200 by the porous chuck table 41 and cuts it with a cutting blade along the division planned line 202.

Explanation of Reference Numerals

[0067] 1 Processing apparatus 10 First grinding unit (processing unit, grinding and polishing unit) 12 Grinding wheel (tool for grinding) 20 Second grinding unit (processing unit, grinding and polishing unit) 22 Grinding wheel (tool for grinding) 41 Porous chuck table 42 Porous plate 45 Fluid supply unit 46 Holding surface 55 Rotation axis 70 Cleaning unit 71 Main body part 72 Vibration part 73 Piezoelectric element 78 End face 81 Nozzle 89 Liquid 90 Positioning unit 100 Control unit 112 Grinding tool (tool for grinding) 200 Workpiece

Claims

1. A processing apparatus for holding and processing a workpiece on a porous chuck table, a porous chuck table that suction-holds a workpiece on a holding surface made of a porous plate, a processing unit that processes the workpiece held by the porous chuck table, a cleaning unit that cleans the holding surface of the porous chuck table, and a control unit that controls each of the components; The cleaning unit comprises: A main body including a vibration part having a piezoelectric element and a nozzle for supplying a liquid that propagates the vibration of the vibration part; a positioning unit that positions the main body at a cleaning position where an end surface of the vibration unit faces the holding surface of the porous plate via a gap of a predetermined size or less, and at a retreated position where the main body is retreated from the porous chuck table; the porous chuck table is configured to be rotatable about a rotation axis perpendicular to the holding surface, The control unit A processing apparatus which positions the main body at the cleaning position, vibrates the vibration part while supplying the liquid from the nozzle into the gap between the end face of the vibration part and the holding surface, and moves the main body in the radial direction of the holding surface while maintaining the cleaning position with the positioning unit while rotating the porous chuck table, cleaning the holding surface with the end face of the vibration part, which has a smaller diameter than the holding surface, thereby cleaning the holding surface from which processing debris has adhered.

2. the porous chuck table includes a fluid supply unit that supplies a fluid to the porous plate and ejects the fluid from the holding surface; 2. The processing apparatus according to claim 1, wherein the control unit operates the fluid supply unit to eject the fluid from the holding surface while the holding surface is being cleaned by the cleaning unit.

3. 3. The processing apparatus according to claim 1, wherein the processing unit is a grinding / polishing unit to which a tool for grinding or polishing a workpiece is attached.

Images