Chuck table

Abstract

To jet from a holding surface of a chuck table, fluid whose momentum is controlled.SOLUTION: A chuck table for sucking and holding a work-piece includes: a holding surface on which the work-piece is placed; a suction port communicating with the holding surface; and a communication passage one end of which communicates with the suction port and the other end of which communicates with a suction source. To the communication passage, a supply source supplying fluid containing water and / or gas is connected; a part or the whole of the communication passage is stuffed with a porous member; and the fluid supplied by the supply source for the communication passage passes through the porous member and is jetted out of the suction port. Preferably, on the holding surface, a groove with which the suction port communicates is formed. The fluid supplied by the supply source for the communication passage and jetted out of the suction port is supplied for the work-piece placed on the holding surface through the groove.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a chuck table on which a workpiece to be processed by a processing apparatus is placed, and which sucks and holds the workpiece to fix it.

Background Art

[0002] When devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), and LEDs (Light Emitting Diodes) are arranged and formed on the surface of a wafer made of a semiconductor material, and the wafer is divided for each device, device chips to be mounted on electronic devices can be formed. Further, by dividing a package substrate manufactured by coating device chips arranged side by side on a substrate with a sealing resin for each device chip, a package device can be manufactured. The device chips and package devices are mounted on electronic devices such as smartphones.

[0003] In recent years, the miniaturization and thinning of electronic devices have been remarkable, and there is also a demand for thinning of device chips and package devices. Therefore, the wafers and package substrates before being divided are ground and thinned.

[0004] A processing apparatus that performs processing such as division and grinding on a workpiece such as a wafer or a package substrate includes a chuck table having a holding surface on the upper surface and holding the workpiece placed on the holding surface, and a processing unit that processes the workpiece held by the chuck table. In the processing apparatus, the workpiece is fixed by the chuck table, and the workpiece is processed by the processing unit.

[0005] Generally, the chuck table is composed of a porous plate and a frame that houses the porous plate so as to be exposed upward (see Patent Document 1). Inside the frame, there is a communication path whose one end reaches the porous plate, and a suction source is connected to the other end of the communication path. When a workpiece is placed on the holding surface and the suction source is operated, negative pressure acts on the workpiece through the communication path and the porous plate, and the workpiece is sucked and held by the chuck table.

[0006] After the machining of the workpiece is completed, the suction of the workpiece by the chuck table is stopped, and the workpiece is unloaded from the holding surface of the chuck table. At this time, a fluid (for example, a mixed fluid of water and high-pressure air) is ejected from the holding surface so that the workpiece can be easily removed from the holding surface. Since the momentum of the fluid is appropriately reduced while passing through the porous plate, the fluid is ejected from the holding surface with an appropriate momentum. The fluid is supplied to the chuck table from facilities such as a factory where the processing device is installed, for example.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Some chuck tables used in processing devices are composed of plates made of aluminum, ceramics, etc., without a porous plate. The upper surface of this plate serves as the holding surface of the chuck table, and suction ports are formed on the holding surface. And a communication path serving as a negative pressure transmission path is formed inside the plate, and this communication path is connected to the suction port. When sucking and holding a workpiece with this chuck table, the workpiece is placed on the holding surface, and negative pressure is applied to the workpiece through the communication path and the suction port.

[0009] Here, after the machining of the workpiece is completed, when unloading the workpiece from the chuck table, it is conceivable to eject the fluid from the holding surface through the communication path and the suction port. However, in a plate without a porous structure, the fluid will be ejected upward from the suction port without the momentum being reduced. Therefore, there is a risk that the workpiece will move greatly and fall off the holding surface, and also, the ejected water will scatter in the processing chamber, which becomes a problem.

[0010] Therefore, it is conceivable to previously reduce the supply pressure of the fluid to the chuck table. However, the fluid is supplied to the processing apparatus from facilities such as a factory where the processing apparatus is installed, and the fluid supplied to the processing apparatus is also used for other purposes. Therefore, if the supply pressure of the fluid is reduced, the fluid will not be suitable for other purposes.

[0011] The present invention has been made in view of such problems, and an object thereof is to provide a chuck table capable of ejecting a fluid with controlled momentum from a holding surface.

Means for Solving the Problems

[0012] According to one aspect of the present invention, there is provided a chuck table for sucking and holding a workpiece, comprising a holding surface on which the workpiece is placed, a suction port communicating with the holding surface, and a communication path having one end communicating with the suction port and the other end communicating with a suction source. A supply source for supplying a fluid containing one or both of water and gas is connected to the communication path, and a porous member is packed in part or all of the communication path. The fluid supplied from the supply source to the communication path passes through the porous member and is ejected from the suction port.

[0013] Preferably, a radially or grid-shaped communication path is disposed inside.

[0014] More preferably, a plate-shaped workpiece can be sucked and held.

[0015] Also, preferably, a groove communicating with the suction port is formed on the holding surface, and the fluid supplied from the supply source to the communication path and ejected from the suction port is supplied to the workpiece placed on the holding surface through the groove.

Effects of the Invention

[0016] In the chuck table according to one aspect of the present invention, a supply source for supplying fluid is connected to a communication passage having one end communicating with a suction port. And a porous member is packed in part or all of this communication passage, and the fluid supplied from the supply source to the communication passage blows out from the suction port through the porous member. That is, since the fluid whose momentum has been reduced by the porous member jets out from the suction port, the work does not move greatly by the fluid, and the jetted fluid is difficult to scatter. Also, since there is no need to change the supply pressure, the use of the fluid for other purposes is not hindered.

[0017] Therefore, according to the present invention, there is provided a chuck table capable of jetting a fluid with controlled momentum from a holding surface.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The chuck table according to this embodiment is incorporated and used in a processing apparatus for processing a work (workpiece) such as a semiconductor wafer or a package substrate. The chuck table is configured to be able to suck and hold the work to be processed. First, the work sucked and held by the chuck table will be described.

[0020] Figures 4 and 5 include cross-sectional views schematically showing the workpiece 1. The workpiece 1 is, for example, a disk-shaped substrate made of a semiconductor such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), GaAs (gallium arsenide), or other semiconductors as a constituent material. A plurality of devices (not shown) such as ICs, LSIs, and LEDs are arranged in a matrix on the surface 1a of the workpiece 1, the workpiece 1 is ground and thinned from the back surface 1b side, and when the workpiece 1 is divided for each device, individual device chips can be formed.

[0021] Alternatively, the workpiece 1 may be a package substrate produced by coating device chips arranged side by side on a substrate with a sealing resin. By dividing the package substrate for each device chip, package devices can be manufactured.

[0022] A tape for protecting the device may be attached to the surface 1a of the workpiece 1. This tape has, for example, a film-shaped base material formed in a circular shape and an adhesive layer (paste layer) provided on the base material. And this base material consists of, for example, a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate. Also, this adhesive layer consists of, for example, an epoxy-based or acrylic-based adhesive. Alternatively, this adhesive layer may be an ultraviolet curable resin that cures when irradiated with ultraviolet rays.

[0023] Note that there are no restrictions on the material, shape, structure, size, etc. of the workpiece 1. For example, the workpiece 1 may include a wafer made of other semiconductor materials or a substrate made of materials such as ceramics, resin, or metal. Similarly, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the devices.

[0024] The workpiece 1 is processed by various processing apparatuses. For example, the workpiece 1 is processed by a cutting apparatus that cuts the workpiece 1 with an annular cutting blade, a laser processing apparatus that can perform laser processing on the workpiece 1 by irradiating a laser beam, a grinding apparatus that can grind the workpiece 1 with a grinding wheel provided with a grinding stone, and other processing apparatuses. The chuck table according to the present embodiment is incorporated into and used in these processing apparatuses.

[0025] Next, taking the grinding apparatus as an example, a processing apparatus incorporating the chuck table according to the present embodiment will be described. However, the processing apparatus incorporating the chuck table is not limited to the grinding apparatus, and other processing apparatuses may also be used. Furthermore, the chuck table may be incorporated into and used in apparatuses other than processing apparatuses, such as a cleaning apparatus.

[0026] FIG. 1 is a perspective view schematically showing a grinding apparatus 2 as an example of a processing apparatus. The X-axis direction (left-right direction) and the Y-axis direction (front-back direction) shown in FIG. 1 are directions orthogonal to each other on a horizontal plane, and the Z-axis direction (up-down direction) is a direction (vertical direction) orthogonal to the X-axis direction and the Y-axis direction.

[0027] The grinding apparatus (processing apparatus) 2 shown in FIG. 1 includes a base 4 that supports or houses each component. An opening 4a is formed on the upper surface side of the front end portion of the base 4, and a transfer unit 6 is provided inside the opening 4a. This transfer unit 6 has, for example, a suction pad that sucks the upper surface side of the workpiece 1 described later.

[0028] In addition, cassette installation areas 8a and 8b are respectively provided diagonally forward to the left and diagonally forward to the right of the transfer unit 6. And on each of the cassette installation areas 8a and 8b, cassettes 10a and 10b capable of accommodating a plurality of workpieces (workpiece 1) are arranged.

[0029] These cassettes 10a and 10b accommodate workpieces (workpiece 1 before grinding) to be processed (ground) in the grinding apparatus 2. And the workpieces processed in the grinding apparatus 2 are accommodated in the cassettes 10a and 10b.

[0030] Further, in the cassettes 10a and 10b shown in FIG. 1, for example, the workpiece 1 is accommodated such that the back surface 1b side faces upward. The conveying unit 6 sucks the upper surface side (for example, the back surface 1b side) of the workpiece 1 by a suction pad. Then, the conveying unit 6 carries out the workpiece 1 from the cassettes 10a and 10b by moving the arm while holding the workpiece 1.

[0031] Furthermore, an alignment mechanism 12 is provided at a position diagonally rearward to the left of the conveying unit 6 and where the workpiece 1 can be conveyed by the conveying unit 6. When the workpiece 1 carried out from the cassette 10a by the conveying unit 6 is carried into the alignment mechanism 12, the alignment mechanism 12 operates to sandwich the workpiece 1 and arrange it at a predetermined position.

[0032] Also, a conveying unit 14 for carrying out the workpiece 1 aligned in the alignment mechanism 12 is provided behind the conveying unit 6 and on the right side of the alignment mechanism 12. This conveying unit 14 has, for example, a suction pad that sucks the upper surface side (for example, the back surface 1b side) of the workpiece 1.

[0033] When the workpiece 1 aligned by the alignment mechanism 12 is sucked by the suction pad of the conveying unit 14 and held by the conveying unit 14, the conveying unit 14 operates to turn the suction pad and convey the workpiece 1 backward.

[0034] Also, a disk-shaped turntable 16 is provided behind the conveying unit 14. This turntable 16 is connected to a rotational drive source (not shown) such as a motor that rotates the turntable 16 around a rotation axis substantially parallel to the Z-axis direction.

[0035] Further, on the turntable 16, a plurality of chuck tables 18 are provided, each of which can suck and hold the lower surface side (for example, the surface 1a side) of the workpiece 1. In FIG. 1, an example is shown in which three chuck tables 18 are arranged at substantially equal intervals along the circumferential direction of the turntable 16. Also, as shown in FIG. 2, each chuck table 18 is supported and fixed to a table base 19 and used.

[0036] This chuck table 18 has a circular upper surface substantially parallel to the horizontal plane (XY plane), and holds the workpiece 1 on this upper surface. That is, the upper surface of the chuck table 18 serves as a holding surface for holding the workpiece 1. Details of the chuck table 18 will be described later.

[0037] Also, the turntable 16 rotates, for example, clockwise in a plan view, and positions each chuck table 18 in the order of the transfer position A, the first grinding position (rough grinding position) B, the second grinding position (finish grinding position) C, and the transfer position A. Then, the workpiece 1 conveyed by the transfer unit 14 is carried into the chuck table 18 positioned at the transfer position A.

[0038] The chuck table 18 is connected to a rotation drive source (not shown) such as a motor that rotates the chuck table 18 around a rotation axis substantially parallel to the Z-axis direction. This rotation drive source rotates the chuck table 18 when the workpiece 1 is ground by a plurality of grinding wheels 48 of the grinding wheels 44a, 44b described later.

[0039] Also, thickness measuring devices 20a, 20b for measuring the thickness of the workpiece 1 held by the chuck table 18 are provided near the first grinding position B and near the second grinding position C, respectively. Each thickness measuring device 20a, 20b measures the change in the thickness of the workpiece 1 over time when the workpiece 1 is ground.

[0040] Specifically, each thickness measuring device 20a, 20b has a pair of height gauges. One of this pair of height gauges has a measuring element that contacts the upper surface (for example, the back surface 1b) of the workpiece 1 that is exposed without being covered by the grinding wheels 44a, 44b described later when the workpiece 1 is being ground.

[0041] Also, the other of the pair of height gauges has a measuring element that contacts the holding surface of the chuck table 18 that is exposed without being covered by the workpiece 1 and the grinding wheels 44a, 44b described later when the workpiece 1 is being ground.

[0042] Therefore, when the workpiece 1 is being ground, the height of the upper surface (for example, the back surface 1b) of the workpiece 1 and the height of the holding surface of the chuck table 18 are respectively measured by the pair of height gauges. And each thickness measuring device 20a, 20b measures the difference between these heights as the thickness of the workpiece 1.

[0043] Also, a columnar support structure 22a is arranged behind the first grinding position B, and a columnar support structure 22b is arranged behind the second grinding position C. And on the front side (surface side) of each support structure 22a, 22b, moving mechanisms 24a, 24b for moving (lifting and lowering) the moving plates 28a, 28b along the Z-axis direction are provided.

[0044] Each moving mechanism 24a, 24b has a pair of guide rails 26 extending along the Z-axis direction. The moving plates 28a, 28b are connected to the front side (surface side) of this pair of guide rails 26 in a slidable manner. Also, between the pair of guide rails 26, a screw shaft 30 extending along the Z-axis direction is arranged.

[0045] And at the upper end of the screw shaft 30, a motor 32 for rotating the screw shaft 30 is connected. Also, on the outer peripheral surface where the thread of the screw shaft 30 is formed, a nut portion (not shown) for accommodating balls that circulate in response to the rotation of the screw shaft 30 is provided, and a ball screw is constituted.

[0046] Also, this nut portion is fixed to the rear surface side (back surface side) of the moving plates 28a and 28b. Therefore, if the screw shaft 30 is rotated by the motor 32, the moving plates 28a and 28b move (ascend and descend) along the Z-axis direction together with the nut portion.

[0047] Further, a grinding unit (processing unit) 34a for rough grinding the workpiece 1 is fixed to the front surface side (front side) of the moving plate 28a. On the other hand, a grinding unit (processing unit) 34b for finish grinding the workpiece 1 is fixed to the front surface side (front side) of the moving plate 28b.

[0048] Therefore, when the moving plate 28a ascends and descends, the grinding unit 34a also ascends and descends, and when the moving plate 28b ascends and descends, the grinding unit 34b also ascends and descends. Each grinding unit 34a and 34b has a hollow cylindrical housing 36 extending along the Z-axis direction.

[0049] A motor 38 is provided at the upper part of this housing 36, and this motor 38 is connected to the base end portion (upper end portion) of a spindle (not shown) accommodated in the housing 36 in a rotatable manner. Further, this spindle extends along the Z-axis direction, and its tip end portion (lower end portion) is exposed from the lower part of the housing 36. A disk-shaped mount 42 made of metal or the like is fixed to the tip end portion of the spindle exposed from the lower part of the housing 36.

[0050] Furthermore, a grinding wheel 44a for rough grinding is mounted on the lower surface side of the mount 42 of the grinding unit 34a, and a grinding wheel 44b for finish grinding is mounted on the lower surface side of the mount 42 of the grinding unit 34b. And each grinding wheel 44a and 44b rotates around a rotation axis substantially parallel to the Z-axis direction by the power transmitted from the motor 38 via the spindle and the mount 42.

[0051] In addition, each grinding wheel 44a, 44b has an annular wheel base whose diameter is approximately equal to the outer diameter of the mount 42. This wheel base is made of a metal such as aluminum or stainless steel, for example. Further, a plurality of grinding wheels 48 are fixed to the lower surface side of the wheel base.

[0052] Each of the plurality of grinding wheels 48 has, for example, a rectangular parallelepiped shape and is arranged at substantially equal intervals along the circumferential direction of the wheel base. Further, each of the plurality of grinding wheels 48 is formed by fixing abrasive grains made of diamond or cBN (cubic Boron Nitride), etc. with a binder such as a metal bond, a resin bond, or a vitrified bond.

[0053] However, as the grinding wheel 48 of the grinding wheel 44a, a grinding wheel suitable for rough grinding is applied, and as the grinding wheel 48 of the grinding wheel 44b, a grinding wheel suitable for finish grinding is applied. Therefore, the average particle size of the abrasive grains included in the grinding wheel 48 of the grinding wheel 44b is smaller than the average particle size of the abrasive grains included in the grinding wheel 48 of the grinding wheel 44a, for example.

[0054] Furthermore, inside each grinding unit 34a, 34b, a grinding fluid supply path (not shown) for supplying a liquid (grinding fluid) such as pure water is provided. Also, a nozzle for supplying the grinding fluid may be provided near each grinding unit 34a, 34b, in place of or in addition to the grinding fluid supply path.

[0055] This grinding fluid is supplied to the contact interface (processing point) between the workpiece 1 and the plurality of grinding wheels 48 when the workpiece 1 is ground by the plurality of grinding wheels 48 of the grinding wheels 44a, 44b. Thereby, the workpiece 1 and the grinding wheel 48 are cooled, and the chips (grinding chips) generated by grinding are washed away.

[0056] And in the grinding unit 34a, each component is arranged so that the locus of the plurality of grinding wheels 48 when the grinding wheel 44a is rotated overlaps with the center of the holding surface of the chuck table 18 positioned at the first grinding position B.

[0057] Similarly, in the grinding unit 34b, the components are arranged such that the trajectories of the plurality of grinding wheels 48 when the grinding wheel 44b is rotated overlap the center of the holding surface of the chuck table 18 positioned at the second grinding position C.

[0058] Also, at a position adjacent to the transfer unit 14 in the X-axis direction, a transfer unit 50 for unloading the workpiece 1 disposed on the chuck table 18 positioned at the transfer position A is provided. This transfer unit 50 includes, for example, a suction pad that sucks the upper surface side (e.g., the back surface 1b side) of the workpiece 1.

[0059] When the ground workpiece 1 is sucked by the suction pad of the transfer unit 50 and held by the transfer unit 50, the transfer unit 50 operates to turn the suction pad and transfer the workpiece 1 forward.

[0060] Also, a cleaning unit 52 for cleaning the workpiece 1 is provided at a position diagonally forward to the right of the transfer unit 50 and at a position where the workpiece 1 can be transferred by the transfer unit 50. When the ground workpiece 1 is carried into the cleaning unit 52 by the transfer unit 50, the cleaning unit 52 operates to clean the workpiece 1. The workpiece 1 that has been processed and cleaned by the cleaning unit 52 is transferred by the transfer unit 6 and housed in the cassettes 10a, 10b.

[0061] In the grinding device (processing device) 2, the workpieces 1 housed in the cassettes 10a, 10b are successively unloaded, processed, and returned. Then, when the processing of all the workpieces 1 housed in the cassettes 10a, 10b is completed, the cassettes 10a, 10b are unloaded from the grinding device 2.

[0062] Here, the chuck table 18 according to the present embodiment that sucks and holds the workpiece 1 will be described. FIG. 2 is a perspective view schematically showing the chuck table 18 placed and fixed on the table base 19, and FIG. 3 is a cross-sectional view schematically showing the chuck table 18. The plate-shaped chuck table 18 is detachable from the table base 19. In the grinding device (processing device) 2, an appropriate type of chuck table 18 is selected according to the size of the workpiece 1 and the content of the processing performed on the workpiece 1, and is fixed to the table base 19 in advance.

[0063] The chuck table 18 includes a holding surface 60 on which the workpiece 1 is placed, a suction port 66 communicating with the holding surface 60, and a communication path 68 having one end communicating with the suction port 66 and the other end communicating with a suction source. When the workpiece 1 is placed on the holding surface 60 and a negative pressure is applied to the workpiece 1 through the communication path 68 and the suction port 66, the chuck table 18 can suck and hold the workpiece 1. Note that grooves 72 arranged vertically and horizontally are formed on the holding surface 60 of the chuck table 18, and the grooves 72 also serve as a transmission path for the negative pressure. Hereinafter, the chuck table 18 will be described in more detail.

[0064] In the chuck table 18 used in the grinding device 2, a plate formed of aluminum or ceramics may be used. The holding surface 60 of the chuck table 18 is formed in a size and shape that can support the entire area of the workpiece 1 from below. For example, when the workpiece 1 is disk-shaped, the holding surface 60 is formed in a circular shape with a diameter larger than that of the workpiece 1.

[0065] Also, the holding surface 60 is formed to be substantially flat. However, when the processing device in which the chuck table 18 is incorporated and used is the grinding device 2, the holding surface 60 is constituted by a conical surface with an extremely small height and the center as the apex. However, for the sake of convenience of explanation, the holding surface 60 is drawn flat in each figure.

[0066] When the grinding wheels 44a and 44b mounted on the grinding units 34a and 34b rotate, the orientation of the chuck table 18 and the like is adjusted so that the annular orbits of the plurality of grinding wheels 48 are parallel to the highest generatrix of the conical holding surface 60. In this case, when the grinding wheel 48 is brought into contact with the back surface 1b of the workpiece 1 while rotating the chuck table 18, grinding of the back surface 1b of the workpiece 1 proceeds in the vicinity of the region overlapping with this generatrix, and the entire back surface 1b of the workpiece 1 is ground with the same strength.

[0067] The groove 72 formed in the holding surface 60 serves as a transmission path for negative pressure. There is no particular limitation on the depth of the groove 72. Also, there is no particular limitation on the formation position of the groove 72. The arrangement of the groove 72 is determined so that the negative pressure spreads widely over the held surface (front surface 1a) of the workpiece 1 and the workpiece 1 is properly sucked and held. Note that the width of the groove 72 is preferably about several millimeters or 1 mm or less. If the groove 72 becomes too wide, the workpiece 1 will sink into the groove 72 without being partially supported, and grinding (processing) cannot be properly performed. The groove 72 is formed in the holding surface 60 by, for example, machining.

[0068] Inside the chuck table 18, a communication passage 68 serving as a transmission path for negative pressure is formed. The communication passage 68 communicates the holding surface 60 and the bottom surface 64 of the chuck table 18. The communication passage 68 arranged inside the plate-shaped chuck table 18 is formed, for example, by advancing the chuck table 18 with a tool such as a drill.

[0069] More specifically, a plurality of horizontal holes are formed by advancing from the side surface 62 of the chuck table 18 in the central direction, and through holes are formed from the holding surface 60 and the bottom surface 64 toward each horizontal hole. Then, the entrance of the horizontal hole is sealed with a filler 76. Then, the communication passage 68 communicating from the bottom surface 64 to the holding surface 60 can be formed in the chuck table 18. The opening on the holding surface 60 side of this communication passage 68 becomes the suction port 66, and the opening on the bottom surface 64 side becomes the negative pressure supply port 70.

[0070] When forming the communication passage 68 in the chuck table 18 in such a manner, the communication passage 68 is disposed inside the chuck table 18 in a radial pattern with the main portion (lateral hole) facing the side surface 62 of the chuck table 18. However, the communication passage 68 may not be formed in the chuck table 18 in a radial pattern. For example, the communication passage 68 may be disposed inside the chuck table 18 in a lattice pattern where the main portion extends vertically and horizontally parallel to the holding surface 60.

[0071] Here, the suction port 66 on the holding surface 60 communicates with the groove 72. Therefore, the negative pressure supplied to the chuck table 18 is transmitted to the groove 72 through the communication passage 68. For example, when the width of the groove 72 is larger than that of the suction port 66, the through-hole is connected to the bottom of the groove 72. In this case, when looking at the through-hole constituting the communication passage 68 from above the chuck table 18, it appears as if a through-hole is formed in the groove 72. In this case, it can be said that the suction port 66 communicates with the holding surface 60 through the groove 72.

[0072] And in this case, several explanations can be considered regarding the position of the suction port 66 on the holding surface 60 that communicates with the holding surface 60. For example, it is also possible to consider the assumed position of the through-hole on the holding surface 60 when the groove 72 is not formed as the position of the suction port 66. Also, it is possible to consider the edge of the upper end of the groove 72 connected to the through-hole as the suction port 66. Furthermore, it is also possible to consider the groove 72 as a component of the communication passage 68. In any case, in the holding surface 60, the region connecting the space on the chuck table 18 and the communication passage 68 is the suction port 66.

[0073] A suction source 80 is connected to the supply port 70 provided on the bottom surface 64 of the chuck table 18 through a supply path 78 provided in the table base 19 or the like. The suction source 80 is, for example, the equipment of a factory where the grinding device (processing device) 2 is installed and is constituted by a pump. A valve 82 is provided in the supply path 78, and by opening and closing the valve 82, it is possible to connect or disconnect the supply port 70 and the suction source 80, or to switch them. Furthermore, the controller (control unit) of the grinding device 2 may control the opening and closing of the valve 82.

[0074] Further, in the communication path 68 of the chuck table 18, in addition to the suction source 80, a supply source 84 for supplying a fluid containing one or both of water and gas is connected. That is, the supply source 84 is connected to the supply port 70 provided on the bottom surface 64 of the chuck table 18 through a supply path 78 provided on the table base 19 or the like.

[0075] Here, the supply source 84 is a facility in the factory where the grinding device (processing device) 2 is installed. A valve 86 is provided in the supply path 78, and by opening and closing the valve 86, it is possible to connect or disconnect the supply port 70 and the supply source 84, or to switch. Further, the controller (control unit) of the grinding device 2 may control the opening and closing of the valve 86.

[0076] Note that the supply source 84 is, for example, a water tank such as pure water, or a gas cylinder such as air or nitrogen gas. Further, the supply source 84 may be constituted by both a water tank and a gas cylinder. In this case, a total of two valves 86, that is, a valve 86 provided between the water tank and the supply path 78 and a valve 86 provided between the gas cylinder and the supply path 78, may be used.

[0077] The usage mode of the chuck table 18 according to the present embodiment will be described. FIG. 4 is a cross-sectional view schematically showing the workpiece 1 sucked and held by the chuck table 18. When sucking and holding the workpiece 1 with the chuck table 18, first, the workpiece 1 is placed on the holding surface 60 of the chuck table 18. At this time, the back surface 1b that becomes the surface to be ground (surface to be processed) of the workpiece 1 is directed upward, and the front surface 1a of the workpiece 1 faces the holding surface 60. Note that a protective member may be attached to the front surface 1a of the workpiece 1, and the workpiece 1 may be placed on the chuck table 18 via the protective member.

[0078] Next, close valve 86 and open valve 82. Then, the suction source 80 is connected to the chuck table 18 through the supply path 78. As a result, the negative pressure derived from the suction source 80 is supplied to the chuck table 18 through the supply path 78. And the negative pressure is transmitted to the workpiece 1 through the supply port 70, the communication path 68, the suction port 66, and the groove 72 of the chuck table 18. That is, the workpiece 1 is sucked and held by the chuck table 18.

[0079] When the machining of the workpiece 1 is completed and the workpiece 1 is unloaded from the chuck table 18, close valve 82 to stop the supply of negative pressure to the workpiece 1. And in order to smoothly peel the workpiece 1 from the holding surface 60 of the chuck table 18, eject fluid from the suction port 66 of the holding surface 60.

[0080] FIG. 5 is a cross-sectional view schematically showing the chuck table 18 that ejects the fluid 88 from the holding surface 60 (suction port 66). When unloading the workpiece 1 from the chuck table 18, close valve 82 and open valve 86. Then, the supply source 84 is connected to the chuck table 18 through the supply path 78. As a result, the fluid 88 derived from the supply source 84 is supplied to the chuck table 18 through the supply path 78. And the fluid 88 passes through the supply port 70, the communication path 68, the suction port 66, and the groove 72 of the chuck table 18 and ejects from the holding surface 60.

[0081] When the fluid 88 ejects from the holding surface 60, the fluid 88 pushes up the workpiece 1 and the workpiece 1 smoothly peels from the holding surface 60. Therefore, it becomes easy to unload the workpiece 1 from the chuck table 18.

[0082] However, if the fluid 88 reaches the holding surface 60 as it is through the communication path 68 provided in the chuck table 18, the fluid 88 will be ejected upward from the suction port 66 without reducing its momentum. Therefore, there is a risk that the workpiece 1 will move greatly and fall from the holding surface 60, and also, the ejected fluid 88 will scatter in the machining chamber of the grinding device 2, which becomes a problem.

[0083] Therefore, it is conceivable to preliminarily reduce the supply pressure of the fluid 88 to the chuck table 18. However, the fluid 88 is supplied from facilities such as the factory where the grinding device (processing device) 2 is installed and is also used for other purposes. Therefore, if the supply pressure of the fluid 88 is reduced, the fluid 88 will not be suitable for other purposes.

[0084] Therefore, in the chuck table 18 according to the present embodiment, a porous member 74 is packed in part or all of the communication passage 68 that serves as a negative pressure or a flow path for the fluid 88. Then, the fluid 88 supplied from the supply source 84 to the communication passage 68 passes through the porous member 74 and blows out from the suction port 66. FIGS. 3 to 5 schematically show the porous member 74 packed in the communication passage 68 in the vicinity of the supply port 70.

[0085] The momentum of the fluid 88 passing through the porous member 74 inside the communication passage 68 is reduced. That is, the fluid 88 whose momentum has been reduced by the porous member 74 jets out from the suction port 66. Therefore, the workpiece 1 does not move greatly due to the fluid 88, and the jetted fluid 88 is not likely to scatter. In addition, since it is not necessary to reduce the supply pressure of the fluid 88 at the supply source 84, the use of the fluid 88 for other purposes is not hindered.

[0086] For example, the porous member 74 is made of a material such as alumina or glass. Alternatively, the porous member 74 may be made of a material such as a metal bond, a resin bond, or a vitrified bond that can also be used for the abrasive material 48 of the grinding wheels 44a and 44b. There are no particular limitations on the porosity, density, particle size of the constituent members, etc. of the porous member 74, and these values may be appropriately determined according to the type and pressure of the fluid 88 supplied to the chuck table 18.

[0087] The porous member 74 preferably has a shape that can block at least a part of the communication passage 68. More specifically, the porous member 74 is preferably formed in a columnar shape having the same outer shape as the cross-sectional shape of the communication passage 68 at the position where the porous member 74 is disposed. Then, the porous member 74 is disposed in the communication passage 68, for example, by being inserted into the communication passage 68 from the suction port 66 or the supply port 70. That is, the porous member 74 is inserted into a through-hole that communicates with the main part of the communication passage 68 from the suction port 66 or the supply port 70.

[0088] Note that the porous member 74 is fixed to the communication passage 68 by being fitted into the through-hole. Alternatively, the porous member 74 is fixed to the communication passage 68 by an adhesive. Alternatively, after the porous member 74 is inserted into the through-hole, the chuck table 18 may be heated to a high temperature and the porous member 74 may be sintered to the wall surface of the through-hole, whereby the porous member 74 is fixed to the communication passage 68.

[0089] However, the communication passage 68 and the porous member 74 shall not be sealed by an adhesive. Alternatively, the internal porous structure of the porous member 74 shall not disappear due to sintering. That is, the communication passage 68 must be capable of allowing negative pressure and the fluid 88 to pass through.

[0090] Note that the arrangement position of the porous member 74 in the communication passage 68 is not limited to this. For example, when a main part (horizontal hole) of the communication passage 68 is formed by digging from the side surface 62 of the chuck table 18, the porous member 74 may be inserted into the main part of this communication passage 68 from the side surface 62 before the backfill material 76 is arranged. In this case, the porous member 74 is arranged in the main part of the communication passage 68.

[0091] Also, the method of disposing the porous member 74 in the communication passage 68 is not limited to this. For example, one of the suction port 66 or the supply port 70 is blocked, and particles serving as raw materials of the porous member 74 are packed into the communication passage 68 from the other. Then, the chuck table 18 is heated to the temperature at which the particles are sintered. Thereby, the porous member 74 is disposed throughout the communication passage 68.

[0092] Note that the momentum (such as pressure and ejection volume) of the fluid 88 supplied from the supply source 84, passing through the communication path 68, and ejected from the holding surface 60 of the chuck table 18 changes depending on the position, amount, size, shape, etc. of the porous member 74 disposed in the communication path 68. Therefore, the position, etc. of the porous member 74 may be determined based on the momentum of the fluid 88 supplied from the supply source 84 to the chuck table 18, the momentum of the fluid 88 suitable for ejection from the holding surface 60, etc.

[0093] For example, when the porous member 74 is disposed in the vicinity of the supply port 70 in the communication path 68 as shown in FIG. 5 etc., since the fluid 88 that has passed through the porous member 74 then further advances through the communication path 68 in a relatively long time, the momentum of the fluid 88 significantly attenuates. On the other hand, when the porous member 74 is disposed in the vicinity of the suction port 66 in the communication path 68, since the fluid 88 that has passed through the porous member 74 then advances through the communication path 68 in a relatively short time, the attenuation amount of the momentum of the fluid 88 becomes small.

[0094] Also, for example, when the porous member 74 is disposed throughout the communication path 68, the momentum of the fluid 88 significantly attenuates. On the other hand, when the porous member 74 is disposed in a part of the communication path 68 as shown in FIG. 5 etc., the attenuation amount of the momentum of the fluid 88 becomes small.

[0095] Furthermore, when a groove 72 through which the suction port 66 communicates with the holding surface 60 is formed, the fluid 88 supplied from the supply source 84 to the communication path 68 and ejected from the suction port 66 is supplied to the work 1 placed on the holding surface 60 through the groove 72. Since the action of the fluid 88 supplied to the work 1 changes depending on the arrangement, length, width, depth, etc. of this groove 72, the position, etc. of the porous member 74 may be determined taking into account the arrangement, etc. of the groove 72.

[0096] As described above, in the chuck table 18 according to the present embodiment, the porous member 74 is disposed in the communication passage 68 that leads from the bottom surface 64 to the holding surface 60. Therefore, the fluid 88 supplied from the supply source 84 has its momentum reduced by the porous member 74 and jets out from the holding surface 60. Therefore, the workpiece 1 does not move significantly due to the fluid 88, and the jetted fluid 88 is less likely to scatter. Also, since there is no need to change the supply pressure or the like of the fluid 88 from the supply source 84, the use of the fluid 88 for other purposes is not hindered.

[0097] In the above embodiment, as illustrated in FIGS. 3 to 5, the case where the porous member 74 is packed in the communication passage 68 in the vicinity of the supply port 70 has been described. However, one aspect of the present invention is not limited to this. FIG. 6 is a cross-sectional view schematically showing the chuck table 18 according to a modified example.

[0098] In one aspect of the present invention, as shown in FIG. 6, the porous member 90 may be disposed in the communication passage 68 at a position away from the suction port 66. The state of the fluid 88 when the fluid 88 that has passed through the porous members 74 and 90 exits the communication passage 68 and jets out from the holding surface 60 may change depending on the position where the porous members 74 and 90 are disposed. Therefore, the positions of the porous members 74 and 90 may be determined so that the state of the fluid 88 when it jets out from the holding surface 60 is an optimal state for the purpose of jetting the fluid 88.

[0099] Also, in the above embodiment, as illustrated in FIGS. 3 to 5, the case where the porous member 74 is provided in a relatively small part of the communication passage 68 has been described. However, one aspect of the present invention is not limited to this.

[0100] In one aspect of the present invention, as shown in FIG. 6, a porous member 90 may be provided in a relatively large portion of the communication passage 68. Alternatively, the entire communication passage 68 may be filled with a porous member. The state of the fluid 88 ejected from the holding surface 60 may change depending on the ratio of the volume of the porous members 74, 90 in the communication passage 68. Therefore, the size and shape of the porous members 74, 90 may be determined so that the state of the fluid 88 when ejected from the holding surface 60 becomes an optimal state for the purpose of ejecting the fluid 88.

[0101] In the above embodiment, the case where the porous member 74 is disposed in the communication passage 68 has been described for the chuck table 18 in which the groove 72 is formed on the holding surface 60. However, one aspect of the present invention is not limited to this. For example, even when the chuck table is composed of a frame body having a circular recess on the upper surface and a disk-shaped porous plate housed in the recess of the frame body, in order to control the momentum of the fluid 88 and the like, an additional porous member may be disposed in the communication passage communicating with the recess.

[0102] Also, in the above embodiment, the chuck table 18 has been described by taking as an example the case where the chuck table 18 is used in the grinding apparatus 2 for grinding the workpiece 1. However, one aspect of the present invention is not limited to this. The chuck table 18 according to one aspect of the present invention may be incorporated and used in various processing apparatuses such as a cutting apparatus for cutting the workpiece 1 with an annular cutting blade, a laser processing apparatus for irradiating the workpiece 1 with a laser beam to perform laser processing on the workpiece 1, and a polishing apparatus for polishing the workpiece 1.

[0103] The structure, method, etc. according to the above embodiment can be appropriately changed and implemented without departing from the scope of the object of the present invention.

Description of Reference Numerals

[0104] 1 Workpiece 1a Surface 1b Back surface 2 Grinding apparatus 4 Base 4a Opening 6 Conveyor Unit 8a, 8b Cassette Installation Areas 10a, 10b Cassettes 12 Alignment Mechanism 14 Conveyor Unit 16 Turntable 18 Chuck Table 19 Table Base 20a, 20b Thickness Measuring Instruments 22a, 22b Support Structures 24a, 24b Moving Mechanisms 26 Guide Rail 28a, 28b Moving Plates 30 Screw Shaft 32 Motor 34a, 34b Grinding Units 36 Housing 38 Motor 42 Mount 44a, 44b Grinding Wheels 48 Grinding Stone 50 Conveyor Unit 52 Cleaning Unit 60 Holding Surface 62 Side Surface 64 Bottom Surface 66 Suction Port 68 Communication Path 70 Supply Port 72 Groove 74, 90 Porous Members 76 Filling Material 78 Supply Path 80 Suction Source 82 Valve 84 Supply Source 86 Valve 88 Fluid

Claims

1. A chuck table that suction-holds a workpiece, A holding surface on which the workpiece is placed; A suction port communicating with the holding surface; a communication passage having one end communicating with the suction port and the other end communicating with a suction source; A supply source that supplies a fluid containing one or both of water and gas is connected to the communication passage; The communication passage is filled with a porous material in part or in its entirety, The fluid supplied from the supply source to the communication passage passes through the porous member and is ejected from the suction port.

2. 2. The chuck table according to claim 1, wherein the communication passages are arranged inside the table in a radial or lattice pattern.

3. 2. The chuck table according to claim 1, wherein the chuck table is capable of suction-holding the plate-shaped workpiece.

4. A groove communicating with the suction port is formed on the holding surface, 2. The chuck table according to claim 1, wherein the fluid supplied from the supply source to the communication passage and ejected from the suction port is supplied to the workpiece placed on the holding surface through the groove.

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