Cleaning Equipment

Abstract

To provide a cleaning device capable of blocking communication between a space on the spindle unit side and a cleaning chamber accommodating a chuck table for a long period of time.SOLUTION: A seal portion that blocks communication between a space between a case and a spindle, and a cleaning chamber includes a ferrofluid in contact with the spindle. Therefore, the communication between the space and the cleaning chamber is cut off without bringing the solids into contact with each other. As a result, wear of the seal portion due to rotation of the spindle is reduced, and communication between the space and the cleaning chamber can be blocked for a long period of time.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cleaning device. [Background technology]

[0002] In the manufacturing process of various electronic components such as semiconductor device chips, plate-shaped workpieces such as silicon wafers on which devices are formed, glass substrates, or resin package substrates are processed using a cutting blade, a laser beam, etc. When the workpieces are processed in this manner, cutting chips, debris, and other processing waste may be generated and adhere to the surface of the workpiece.

[0003] Therefore, after processing, the workpiece is washed in a washing device having a washing chamber that houses a chuck table with a flat holding surface and a nozzle that supplies a washing liquid to the holding surface. This chuck table is generally capable of sucking the workpiece by generating a negative pressure in the space above the holding surface and separating the workpiece from the workpiece by generating a positive pressure in the space above the holding surface, and is also capable of rotating about a rotation axis that passes through the center of the holding surface and is perpendicular to the holding surface.

[0004] In this cleaning device, the back side of the workpiece is suction-held on the chuck table, and while the chuck table is rotating, a cleaning liquid is supplied from a nozzle to the front surface of the workpiece. This removes cutting chips or debris adhering to the front surface of the workpiece. The chuck table used in this manner is rotatably supported by a spindle unit.

[0005] The spindle unit has a spindle that supports the chuck table and a bearing that rotatably supports the spindle. The chuck table rotates together with the spindle when a motor connected to an end of the spindle is operated. In order to prevent lubricant such as grease provided inside the bearing from scattering around, the spindle and the bearing are housed in a case in the spindle unit.

[0006] Furthermore, the space above the holding surface of the chuck table communicates with a negative pressure supply pipe and a positive pressure supply pipe connected to the case via a negative or positive pressure supply pipe formed inside the spindle and a pressure variable section, which is a space defined by an oil seal between the case and the spindle. A negative pressure supply source connected to the negative pressure supply pipe operates to generate a negative pressure in the space above the holding surface, and a positive pressure supply source connected to the positive pressure supply pipe operates to generate a positive pressure in the space above the holding surface. Note that lubricating oil is often provided at the interface between the oil seal and the spindle so as not to impede the rotation of the spindle.

[0007] Here, the spindle has an end protruding from the case so as to be connected to the chuck table. The cleaning chamber housing the chuck table is provided with an opening into which the end of the spindle is inserted. Therefore, the space between the case and the spindle may communicate with the cleaning chamber through this opening. In this case, lubricant scattered from the bearing and / or lubricating oil scattered from the interface between the oil seal and the spindle may get mixed into the cleaning chamber and adhere to the surface of the workpiece.

[0008] For this reason, in devices having such a chuck table, a seal member is generally provided to block communication between the space on the chuck table side and the space on the spindle unit side (see, for example, Patent Document 1). This seal member is, for example, a V-ring, and is provided so that its lip portion comes into contact with the rotatable sealed portion. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2018-73930 A Summary of the Invention [Problem to be solved by the invention]

[0010] When the sealing member comes into contact with the rotatable sealed part, the sealing member wears as the sealed part rotates, making it difficult to block communication between the space on the chuck table side and the space on the spindle unit side over a long period of time.

[0011] In view of this, an object of the present invention is to provide a cleaning device that is capable of blocking communication between the space on the spindle unit side and the cleaning chamber that houses the chuck table for a long period of time. [Means for solving the problem]

[0012] According to the present invention, there is provided a cleaning device comprising a chuck table which holds a workpiece on a holding surface, a nozzle which supplies a cleaning liquid to the workpiece held on the chuck table, and a spindle unit which rotatably supports the chuck table, and which cleans the workpiece in a cleaning chamber which houses the chuck table and the nozzle, the spindle unit having a spindle which supports the chuck table, a bearing which rotatably supports the spindle, and a case which houses a part of the spindle and the bearing, a pressure variable section and an opening section are provided between the case and the spindle, and the pressure variable section comprises a negative pressure supply pipe and a positive pressure supply pipe which are connected to the case, and a negative or positive pressure supply pipe which is formed inside the spindle and communicates with a space above the holding surface. and is disposed at a position farther from the chuck table than the bearing, the open portion is provided between the bearing and the pressure variable portion, and is opened via a through hole formed in the case or an open tube connected to the case, the spindle has an end portion protruding from the case, a part of the cleaning chamber is defined by a cover member having an opening into which the end portion of the spindle is inserted, and a seal portion is provided between the cover member and the end portion of the spindle to block communication between the space between the case and the spindle and the cleaning chamber, and the seal portion has an annular magnet ring provided on an inner circumferential surface that defines the opening of the cover member, and a magnetic fluid provided inside the magnet ring and in contact with the end portion of the spindle.The magnetic force of the magnet ring is 400 to 800 G, and the thickness of the magnet ring is 3 to 5 mm. A cleaning apparatus is provided.

[0013] Furthermore, in the present invention, it is preferable that the end of the spindle has a cylindrical sealed portion that comes into contact with the magnetic fluid, and a cylindrical extending portion that extends from the sealed portion toward the chuck table and has the same diameter as the sealed portion. In the present invention, it is also preferable that there is no communication passage between the space between the bearing and the seal portion and the cleaning chamber other than the communication passage in which the seal portion is provided to block communication therebetween. Effect of the Invention

[0014] In the present invention, the seal that blocks communication between the space between the case and the spindle and the cleaning chamber has a magnetic fluid that contacts the spindle. Therefore, in the present invention, communication between the space and the cleaning chamber is blocked without solids coming into contact with each other. As a result, wear on the seal that accompanies the rotation of the spindle is reduced, and communication between the space and the cleaning chamber can be blocked for a long period of time.

[0015] Furthermore, in the present invention, an open section is provided between the bearing and the pressure variable section, which suppresses pressure fluctuations around the bearing even if leakage occurs from the pressure variable section to the open section in response to pressure fluctuations in the pressure variable section, thereby suppressing scattering of lubricants such as grease provided inside the bearing.

[0016] In addition, when such an opening is provided, the pressure fluctuation around the seal is suppressed, and therefore the magnetic fluid contained in the seal is prevented from leaking out, so that the communication between the space between the case and the spindle and the cleaning chamber can be blocked for a long period of time. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view illustrating an example of a processing apparatus. [Diagram 2] FIG. 2 is a partially cutaway perspective view that illustrates an example of a cleaning device. [Diagram 3]FIG. 3 is a partially sectional side view that typically shows the spindle, the case, the cover member, and the like. [Figure 4] FIG. 4 is a partially enlarged view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing a schematic example of a processing device (cutting device) having a cleaning device. Note that the X-axis direction (front-back direction) and the Y-axis direction (left-right direction) shown in Fig. 1 are directions perpendicular to each other on a horizontal plane, and the Z-axis direction (up-down direction) is a direction (vertical direction) perpendicular to the X-axis direction and the Y-axis direction.

[0019] The cutting device 2 shown in Fig. 1 includes a base 4 that supports each of the components. A rectangular opening 4a whose longitudinal direction is parallel to the X-axis direction is formed on the upper surface of the base 4. A movable table 6 and a bellows-shaped dust-proof and drip-proof cover 8 that expands and contracts as the movable table 6 moves are provided inside the opening 4a. An X-axis direction moving mechanism (not shown) that moves the movable table 6 along the X-axis direction is provided below the dust-proof and drip-proof cover 8.

[0020] A chuck table 10 is provided on the upper surface of the moving table 6. The chuck table 10 has a disk-shaped porous plate 10a exposed upward, and has the function of suction-holding a workpiece placed on the porous plate 10a. The upper surface of the porous plate 10a is generally flat, and serves as a holding surface for holding the workpiece. A suction passage (not shown) is formed inside the chuck table 10, one end of which is connected to a suction source (not shown) such as an ejector provided outside the chuck table 10.

[0021] The other end of the suction path reaches the porous plate 10a. Therefore, when the suction source is operated with a workpiece placed on the holding surface, the workpiece is sucked and held on the chuck table 10. Furthermore, the chuck table 10 is connected to a chuck table rotation drive source (not shown) such as a motor. When the chuck table rotation drive source is operated, the chuck table 10 rotates around a rotation axis that passes through the center of the holding surface and is perpendicular to the holding surface.

[0022] A support structure 12 is provided near the opening 4a on the upper surface of the base 4. The support structure 12 includes an erected portion 12a extending along the Z-axis direction from the upper surface of the base 4, and an arm portion 12b extending along the Y-axis direction from the upper end of the erected portion 12a so as to cross the opening 4a. A Y-axis direction moving mechanism 14 is provided on the front side of the arm portion 12b.

[0023] The Y-axis direction moving mechanism 14 is fixed to the front surface of the arm portion 12b and includes a pair of Y-axis guide rails 16 extending along the Y-axis direction. A Y-axis moving plate 18 is connected to the front surface of the pair of Y-axis guide rails 16 in a manner that allows it to slide along the pair of Y-axis guide rails 16.

[0024] Further, a screw shaft 20 extending along the Y-axis direction is disposed between the pair of Y-axis guide rails 16. A motor (not shown) for rotating the screw shaft 20 is connected to one end of the screw shaft 20. A nut portion (not shown) for accommodating balls that roll on the surface of the rotating screw shaft 20 is provided on the surface of the screw shaft 20 on which a spiral groove is formed, thereby forming a ball screw.

[0025] That is, when the screw shaft 20 rotates, the balls circulate inside the nut portion, and the nut portion moves along the Y-axis direction. This nut portion is fixed to the rear surface side of the Y-axis moving plate 18. Therefore, when the screw shaft 20 is rotated by a motor connected to one end of the screw shaft 20, the Y-axis moving plate 18 moves along the Y-axis direction together with the nut portion.

[0026] A Z-axis direction moving mechanism 22 is provided on the front side of the Y-axis moving plate 18. The Z-axis direction moving mechanism 22 is fixed to the front side of the Y-axis moving plate 18 and includes a pair of Z-axis guide rails 24 extending along the Z-axis direction. A Z-axis moving plate 26 is connected to the front side of the pair of Z-axis guide rails 24 in a manner that allows it to slide along the pair of Z-axis guide rails 24.

[0027] Further, a screw shaft 28 extending along the Z-axis direction is disposed between the pair of Z-axis guide rails 24. A motor 30 for rotating the screw shaft 28 is connected to one end of the screw shaft 28. A nut portion (not shown) for accommodating balls that roll on the surface of the rotating screw shaft 28 is provided on the surface of the screw shaft 28 on which a spiral groove is formed, thereby forming a ball screw.

[0028] That is, when the screw shaft 28 rotates, the balls circulate inside the nut portion, causing the nut portion to move along the Z-axis direction. This nut portion is fixed to the rear surface side of the Z-axis moving plate 26. Therefore, when the screw shaft 28 is rotated by the motor 30, the Z-axis moving plate 26 moves along the Z-axis direction together with the nut portion.

[0029] A cutting unit 32 is fixed to the lower part of the Z-axis moving plate 26. The cutting unit 32 has a cylindrical spindle housing 34 whose longitudinal direction is parallel to the Y-axis direction. A columnar spindle (not shown) whose longitudinal direction is parallel to the Y-axis direction is accommodated in the spindle housing 34. This spindle is supported by the spindle housing 34 in a rotatable state.

[0030] The tip of the spindle protrudes outside the spindle housing 34, and a cutting blade 36 having an annular cutting edge is attached to this tip. The base end of the spindle is connected to a rotary drive source for the cutting blade (not shown), such as a motor, which is built into the spindle housing 34.

[0031] An imaging unit 38 is provided at a position adjacent to the cutting unit 32 in the X-axis direction and fixed to the lower part of the Z-axis moving plate 26. The imaging unit 38 includes, for example, a light source such as an LED (Light Emitting Diode), an objective lens, and an imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0032] The cutting device 2 processes the workpiece in the following order, for example. First, the imaging unit 38 captures an image of the workpiece held by suction on the chuck table 10. Next, based on the image obtained by this imaging, the cutting unit 32 and the workpiece are aligned. Specifically, the Y-axis direction moving mechanism 14 and / or the Z-axis direction moving mechanism 22 adjust the position of the cutting unit 32, and / or the X-axis direction moving mechanism and / or the chuck table rotation drive source adjust the position and / or orientation of the chuck table 10 that holds the workpiece by suction.

[0033] Next, the cutting blade 36 is brought into contact with the workpiece while rotating. Specifically, while the cutting blade rotary drive source rotates the spindle with the cutting blade 36 attached to its tip, the Y-axis direction moving mechanism 14 and / or the Z-axis direction moving mechanism 22 move the cutting unit 32, and / or the X-axis direction moving mechanism and / or the chuck table rotary drive source move the chuck table 10 that suction-holds the workpiece. In this way, the desired processing is performed on the workpiece.

[0034] Furthermore, a cleaning device 40 is provided at a position in front of the support structure 12 on the upper surface of the base 4. Fig. 2 is a partially cutaway perspective view showing the cleaning device 40. The cleaning device 40 has a chuck table 42. The chuck table 42 has a disk-shaped porous plate 42a exposed upward and has the function of suction-holding a workpiece placed on the porous plate 42a. The upper surface of the porous plate 42a is generally flat and serves as a holding surface for holding the workpiece.

[0035] A cleaning chamber body 44 is provided around the chuck table 42, surrounding the chuck table 42. The cleaning chamber body 44 has a cylindrical outer peripheral wall 44a, an annular bottom wall 44b extending radially inward from the lower end of the outer peripheral wall 44a, and a cylindrical inner peripheral wall 44c standing upright from the inner end of the bottom wall 44b.

[0036] An exhaust port (not shown) is provided in the outer peripheral wall 44a, and this exhaust port is connected to an exhaust pump (not shown) via an exhaust pipe 46. A drain port 48 is provided in the bottom wall 44b, and a drain pipe 50 extending downward is connected to the drain port 48. A plurality of (e.g., three) support legs 52 are fixed to the lower surface of the bottom wall 44b. The plurality of support legs 52 are provided at approximately equal intervals along the circumferential direction of the bottom wall 44b, and support the cleaning chamber body 44.

[0037] A disk-shaped lid (not shown) is provided above the cleaning chamber main body 44. The diameter of this lid is longer than the inner diameter of the outer peripheral wall 44a. The lower surface of this lid is disposed in contact with the upper surface of the outer peripheral wall 44a, thereby preventing cutting chips attached to the workpiece or cleaning liquid used for cleaning from scattering onto the upper surface of the base 4 when the workpiece is cleaned.

[0038] A cleaning unit 54 and a drying unit 56 are disposed inside the outer peripheral wall 44a. The cleaning unit 54 and the drying unit 56 each have a pipe-shaped shaft portion 54a, 56a that is inserted into the bottom wall 44b. The shaft portions 54a, 56a are pipe-shaped members that extend outside the chuck table 42 in a direction perpendicular to the holding surface of the chuck table 42. A rotation drive source (not shown) such as a motor for rotating the shaft portions 54a, 56a is connected to the lower end sides of the shaft portions 54a, 56a.

[0039] Arms 54b, 56b are connected to the upper ends of the shafts 54a, 56a. The arms 54b, 56b are pipe-shaped members extending in a direction parallel to the holding surface of the chuck table 42 with a length equivalent to the distance from the upper ends of the shafts 54a, 54a to the center of the chuck table 42. Nozzles 54c, 56c facing downward are provided at the tips of the arms 54b, 56b (the ends of the arms 54b, 56b not connected to the shafts 54a, 56a).

[0040] Furthermore, the shaft portion 54a and the arm portion 54b are connected to a cleaning liquid supply source (not shown). Therefore, for example, after the shaft portion 54a is rotated so that the nozzle 54c is positioned above the chuck table 42, when cleaning liquid is supplied from the cleaning liquid supply source to the shaft portion 54a and the arm portion 54b, the cleaning liquid is supplied to the holding surface of the chuck table 42 from the nozzle 54c.

[0041] In addition, the shaft portion 56a and the arm portion 56b are connected to an air supply source (not shown). Therefore, for example, after the shaft portion 56a is rotated so that the nozzle 56c is positioned above the chuck table 42, when air is supplied from the air supply source to the shaft portion 56a and the arm portion 56b, air is supplied to the holding surface of the chuck table 42 from the nozzle 56c.

[0042] A spindle unit 58 passes vertically through a cylindrical space present inside the inner peripheral wall 44c. The spindle unit 58 has a spindle 60 made of ferritic or martensitic stainless steel or the like. The upper end side of the spindle 60 is connected to the chuck table 42 to support the chuck table 42. A motor 62 is connected to the lower end of the spindle 60. When the motor 62 is operated, the chuck table 42 rotates about a rotation axis that passes through the center of the holding surface and is perpendicular to the holding surface.

[0043] The motor 62 is supported by a support mechanism 64 in such a manner that it can move up and down. The support mechanism 64 includes a plurality of (e.g., three) air cylinders 66 attached to the motor 62, and a support leg 68 is connected to the lower part of each air cylinder 66. When the plurality of air cylinders 66 are operated simultaneously, the motor 62 and the chuck table 42 rise and fall.

[0044] For example, when a workpiece is loaded or unloaded in the cleaning device 40, the support mechanism 64 is operated to position the chuck table 42 at a predetermined load / unload position, and when the workpiece is cleaned, the chuck table 42 is positioned at a cleaning position below the load / unload position. Note that Fig. 2 shows the cleaning device 40 in a schematic state in which the chuck table 42 is at the load / unload position.

[0045] A case 70 and a cover member 72 are provided around the spindle 60. Fig. 3 is a partially cross-sectional side view showing the spindle 60, the case 70, the cover member 72, etc., and Fig. 4 is a partially enlarged view of Fig. 3. Figs. 3 and 4 show the cleaning device 40 in a state where the chuck table 42 is in the cleaning position.

[0046] The case 70 has a cylindrical shape with an outer diameter shorter than the inner diameter of the inner circumferential wall 44c, and is fixed to the motor 62 via a connecting member (not shown). An outer ring of a bearing 74 is fixed to the inner circumferential surface of the upper part of the case 70. The inner ring of the bearing 74 contacts the spindle 60 to rotatably support the spindle 60.

[0047] Furthermore, the case 70 is provided with three through holes that penetrate the case 70 in the radial direction, lined up one above the other. Of these three through holes, the through hole closest to the bearing 74 is connected to a pipe-shaped open tube 76. The open tube 76 communicates between the annular space (open portion) A between the case 70 and the spindle 60 and the space outside the case 70. It should be noted that the open tube 76 does not have to be provided. In other words, the open portion A may communicate with the space outside the case 70 via a through hole that penetrates the case 70.

[0048] The remaining two through holes are respectively connected to a pipe-shaped negative pressure supply pipe 78 and a positive pressure supply pipe 80. The negative pressure supply pipe 78 communicates between an annular space (pressure variable part) B between the case 70 and the spindle 60, which is farther from the bearing 74 than the open part A, and a negative pressure supply source (suction source) such as an ejector. The positive pressure supply pipe 80 communicates between the pressure variable part B and a positive pressure supply source such as an air supply source.

[0049] Furthermore, annular oil seals 82a, 82b are provided at the boundary between the open portion A and the pressure variable portion B and at the boundary between the pressure variable portion B and the external space below the pressure variable portion B. The pressure variable portion B can be communicated with a negative pressure or positive pressure supply pipe 60a formed inside the spindle 60. The negative pressure or positive pressure supply pipe 60a communicates with a space above the holding surface of the chuck table 42 via a flow path (not shown) formed inside the chuck table 42.

[0050] The cover member 72 has an annular top wall 72a and a cylindrical side wall 72b extending downward from the outer end of the top wall 72a. The inner diameter of the top wall 72a is longer than the inner diameter of the bearing 74. The outer diameter of the top wall 72a and the inner diameter of the side wall 72b are also longer than the outer diameter of the inner circumferential wall 44c.

[0051] The upper end of the spindle 60 protruding from the case 70 is inserted into the inside of the top wall 72a. In other words, the cover member 72 has an opening into which the upper end of the spindle 60 is inserted. In addition, an annular seal portion 84 is provided between the cover member 72 and the upper end of the spindle 60 to block communication between the space between the case 70 and the spindle 60 (for example, the open portion A and the pressure variable portion B) and the space on the chuck table 42 side.

[0052] The seal portion 84 has an annular magnet ring 84a provided on the inner peripheral surface of the top wall 72a. The magnet ring 84a is made of a permanent magnet, and is provided so that the north pole and the south pole are in contact with a pair of annular ball pieces 84b, respectively. In addition, a magnetic fluid 84c is provided between the ball pieces 84b and the spindle 60.

[0053] The magnetic fluid 84c is held along the magnetic flux lines formed between the magnet ring 84a and the ball piece 84b and the spindle 60. The magnetic fluid 84c is, for example, an alkylnaphthalene-based magnetic fluid containing ferromagnetic particles such as magnetite or manganese zinc ferrite and a surfactant. Alternatively, the magnetic fluid 84c may be a fluorine oil-based magnetic fluid containing ferromagnetic particles and a surfactant.

[0054] Here, when the cleaning device 40 is transported, the spindle 60 may be tilted, and as a result, the magnetic fluid 84c may spread outside the space between the ball pieces 84b of the spindle 60. Even in such a case, the spindle 60 preferably has a shape that generates a magnetic field that can suppress the outflow of the magnetic fluid 84c.

[0055] For example, the upper end of the spindle 60, which protrudes from the case 70 and is inserted into the opening (inside the top wall 72a) of the cover member 72, preferably has a cylindrical sealed portion that comes into contact with the magnetic fluid 84c and an extending portion that extends upward from the sealed portion and has the same diameter as the sealed portion. When the extending portion is provided in this manner, even if the magnetic fluid 84c spreads upward from the space between the ball pieces 84b of the spindle 60, the outflow of the magnetic fluid 84c is suppressed.

[0056] Furthermore, when the spindle 60 rotates, friction between the spindle 60 and the magnetic fluid 84c generates frictional heat. If the spindle 60 is heated by the frictional heat, for example, the oil seals 82a and 82b may deteriorate.

[0057] Therefore, it is preferable that the magnetic force of the magnet ring 84a is as weak as possible while still allowing an amount of magnetic fluid 84c capable of blocking communication between the above-mentioned two spaces to be held between the ball piece 84b and the spindle 60. For example, it is preferable that the magnetic force of the magnet ring 84a is 400 to 800 G.

[0058] Similarly, the thickness of the magnet ring 84a is preferably as thin as possible while still allowing an amount of magnetic fluid 84c capable of blocking communication between the above-mentioned two spaces to be held between the ball piece 84b and the spindle 60. For example, the thickness of the magnet ring 84a is preferably as thin as possible so that the magnetic fluid 84c in contact with the pair of ball pieces 84b is integrated without being separated, as shown in Fig. 4. Specifically, the thickness of the magnet ring 84a is preferably 3 to 5 mm.

[0059] 3, the lower surface of the top wall 72a of the cover member 72 comes sufficiently close to the upper surface of the inner circumferential wall 44c of the cleaning chamber body 44 when the chuck table 42 is in the cleaning position. Therefore, in the cleaning device 40, a cleaning chamber is defined by the cleaning chamber body 44, the lid arranged to contact the upper surface of the outer circumferential wall 44a of the cleaning chamber body 44, the cover member 72, and the seal portion 84.

[0060] The cleaning of the workpiece in the cleaning device 40 included in the cutting device 2 is performed, for example, in the following order. First, the workpiece that has been machined as described above is placed on the chuck table 42 that is at the carry-in / out position. Next, the chuck table 42 is moved to the cleaning position, and then the workpiece is sucked and held on the chuck table 42.

[0061] Next, a lid is placed in contact with the upper surface of the outer peripheral wall 44a of the cleaning chamber body 44 to form a cleaning chamber, and the shaft portion 54a is rotated so that the nozzle 54c of the cleaning unit 54 is positioned above the workpiece. Next, with the cleaning chamber evacuated via the exhaust pipe 46, a cleaning liquid is supplied to the workpiece from the nozzle 54c while rotating the chuck table 42. This removes cutting debris and the like adhering to the surface of the workpiece.

[0062] Next, the shaft portion 54a is rotated so that the nozzle 54c of the cleaning unit 54 is retracted from above the workpiece, and the shaft portion 56a is rotated so that the nozzle 56c of the drying unit 56 is positioned above the workpiece. Next, air is supplied to the workpiece from the nozzle 56c while rotating the chuck table 42. This removes the cleaning liquid and the like adhering to the surface of the workpiece.

[0063] Next, the shaft portion 56a is rotated so as to retract the nozzle 56c of the drying unit 56 from above the workpiece. Next, the chuck table 42 is moved to the carry-in / out position, and then the workpiece is carried out from the chuck table 42. This completes the cleaning of the workpiece.

[0064] In the cleaning device 40, the seal portion 84 that blocks communication between the space between the case 70 and the spindle 60 (e.g., the open portion A and the pressure variable portion B) and the cleaning chamber has a magnetic fluid 84c that contacts the spindle 60. Therefore, in the cleaning device 40, communication between the space and the cleaning chamber is blocked without solids coming into contact with each other. As a result, wear of the seal portion 84 caused by the rotation of the spindle 60 is reduced, and communication between the space and the cleaning chamber can be blocked for a long period of time.

[0065] Furthermore, in the cleaning device 40, an open part A is provided between the bearing 74 and the pressure variable part B. This suppresses pressure fluctuations around the bearing 74 even if leakage occurs from the pressure variable part B to the open part A in response to pressure fluctuations in the pressure variable part B. This suppresses scattering of lubricant such as grease provided inside the bearing 74.

[0066] Furthermore, when such an opening A is provided, the pressure fluctuation around the seal portion 84 is also suppressed. Therefore, the magnetic fluid 84c contained in the seal portion 84 is prevented from leaking out. As a result, the communication between the space between the case 70 and the spindle 60 and the cleaning chamber can be blocked for a long period of time.

[0067] The structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0068] 2:Cutting device 4: Base (4a: opening) 6: Moving table 8: Dust-proof and water-resistant cover 10: Chuck table (10a: Porous plate) 12: Support structure (12a: standing part, 12b: arm part) 14:Y-axis direction movement mechanism 16: Y-axis guide rail 18: Y-axis moving plate 20: Screw shaft 22:Z-axis direction movement mechanism 24: Z-axis guide rail 26: Z-axis moving plate 28: Screw shaft 30: Motor 32: Cutting unit 34: Spindle housing 36: Cutting blade 38: Imaging unit 40: Cleaning equipment 42: Chuck table (42a: Porous plate) 44: cleaning chamber body (44a: outer peripheral wall, 44b: bottom wall, 44c: inner peripheral wall) 46: Exhaust pipe 48:Drain port 50: Drain pipe 52:Support leg 54: cleaning unit (54a: shaft, 54b: arm, 54c: nozzle) 56: Drying unit (56a: shaft, 56b: arm, 56c: nozzle) 58: Spindle unit 60: Spindle (60a: Negative or positive pressure supply pipe) 62: Motor 64:Support mechanism 66: Air cylinder 68:Support leg 70: Case 72: Cover member 74: Bearing 76:Open tube 78: Negative pressure supply pipe 80: Positive pressure supply pipe 82a, 82b: Oil seal 84: Seal part (84a: magnet ring, 84b: ball piece, 84c: magnetic fluid)

Claims

1. A cleaning device comprising: a chuck table that holds a workpiece on a holding surface; a nozzle that supplies a cleaning liquid to the workpiece held on the chuck table; and a spindle unit that rotatably supports the chuck table, and cleans the workpiece in a cleaning chamber that houses the chuck table and the nozzle, The spindle unit comprises: A spindle supporting the chuck table; A bearing that rotatably supports the spindle; a case that houses a portion of the spindle and the bearing; A pressure variable portion and an opening portion are provided between the case and the spindle, the pressure varying unit is provided between a negative pressure supply pipe and a positive pressure supply pipe connected to the case, and a negative pressure or positive pressure supply pipe formed inside the spindle and communicating with a space above the holding surface, and is disposed at a position farther from the chuck table than the bearing; the opening is provided between the bearing and the pressure variable portion, and is opened via a through hole formed in the case or an opening pipe connected to the case; The spindle has an end that projects from the case; the washing chamber is defined in part by a cover member having an opening through which the end of the spindle is inserted; a seal portion is provided between the cover member and the end of the spindle to block communication between the space between the case and the spindle and the cleaning chamber; The seal portion is an annular magnet ring provided on an inner circumferential surface of the cover member that defines the opening; a magnetic fluid disposed inside the magnet ring and in contact with the end of the spindle; The magnetic force of the magnet ring is 400 to 800 G. The cleaning device is characterized in that the thickness of the magnet ring is 3 to 5 mm.

2. 2. The cleaning device according to claim 1, wherein the end of the spindle has a cylindrical sealed portion that contacts the magnetic fluid, and a cylindrical extending portion that extends from the sealed portion toward the chuck table and has the same diameter as the sealed portion.

3. A cleaning device as described in claim 1 or 2, in which there is no communication passage between the space between the bearing and the seal portion and the cleaning chamber other than the communication passage in which the seal portion is provided to block communication between them.

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