Conveying device

Abstract

To provide a conveying device that can appropriately convey a workpiece having warpage to a holding table.SOLUTION: A conveying device conveys a workpiece having warpage to a holding table that sucks and holds the workpiece on a holding surface, and comprises: a holding unit that holds the workpiece; a motor that generates a power to bring the holding unit closer to the holding surface or separate the holding unit from the holding surface; and a controller that is connected with the motor. The holding unit includes: a support base; a suction part that is provided on the support base and connected with a suction source, and sucks and holds the workpiece with a suction force generated by the suction source; and a pressing part that is provided on the support base and presses the workpiece against the holding surface. The controller monitors the torque of the motor when the workpiece is pressed against the holding surface by the pressing part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transport device for transporting a workpiece. [Background technology]

[0002] A wafer on which a plurality of devices are formed is divided and diced to produce chips equipped with devices (device chips). A package substrate is formed by mounting a plurality of device chips on a predetermined substrate and covering and sealing the mounted device chips with a resin layer (mold resin). A chip equipped with a plurality of packaged device chips (packaged device) is manufactured by dividing and dicing this package substrate. The device chips and package devices are incorporated into various electronic devices such as mobile phones and personal computers.

[0003] When dividing a workpiece such as a wafer or a package substrate into chips, the workpiece is processed by various processing devices. For example, a cutting device that cuts the workpiece with an annular cutting blade, a laser processing device that performs laser processing on the workpiece, etc. are used to divide a wafer or a package substrate. Also, a grinding device is used to grind and thin the wafer or package substrate before division, thereby obtaining thin chips.

[0004] The above-mentioned processing device includes a holding table that holds the workpiece by suction on a holding surface, and a transport device (transport mechanism) that transports the workpiece. When the processing device processes the workpiece, the workpiece is automatically transported to the holding table by the transport device (see Patent Documents 1 and 2).

[0005] However, warping may occur in the workpiece processed by the processing device during the manufacturing or processing process. For example, when a disk-shaped wafer is subjected to a heat treatment or a thinning treatment, the outer periphery of the wafer may be deformed so as to warp upward. In addition, when a package substrate is manufactured, if a resin layer is cooled after a heat treatment for hardening the resin layer, the resin layer may shrink, causing warping of the package substrate.

[0006] When a workpiece is held by a holding table, a suction force (negative pressure) is applied to the holding surface of the holding table while the workpiece is placed on the holding surface of the holding table. However, if the workpiece is warped, the workpiece and the holding surface may not come into proper contact with each other, causing the suction force to leak, and the holding table may not be able to hold the workpiece sufficiently. In view of this, a conveying device has been proposed that can convey the workpiece to the holding table while correcting the warp of the workpiece (see Patent Document 3). By correcting the warp of the workpiece, it is possible to bring the workpiece into proper contact with the holding surface of the holding table, preventing the suction force from leaking, and the workpiece is reliably suction-held by the holding table. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2003-243483 A [Patent Document 1] JP 2022-136621 A [Patent Document 1] JP 2015-98073 A Summary of the Invention [Problem to be solved by the invention]

[0008] In order to convey the workpiece to the holding table while correcting the warpage of the workpiece, for example, a conveying device capable of pressing the workpiece against the holding surface when placing the workpiece on the holding surface of the holding table is used. By pressing the workpiece against the holding surface, the workpiece is deformed to conform to the holding surface, and the workpiece can be sucked and held by the holding table in a state in which the warpage of the workpiece has been corrected.

[0009] However, the material, thickness, degree of warping, etc. of the workpiece vary from workpiece to workpiece, and the pressing force required to correct the warping also differs for each workpiece. Therefore, even if the conveying device is operated uniformly to press the workpiece against the holding surface of the holding table, the workpiece may not be properly held by the holding table. For example, if the force pressing the workpiece against the holding surface is insufficient, the warping will not be corrected sufficiently and the suction force leakage at the holding surface cannot be prevented. On the other hand, if the workpiece is pressed against the holding surface too much, the workpiece may be damaged, such as chipped or cracked.

[0010] The present invention has been made in consideration of the above problems, and has an object to provide a conveying device capable of properly conveying a warped workpiece to a holding table. [Means for solving the problem]

[0011] According to one aspect of the present invention, there is provided a transport device for transporting a warped workpiece to a holding table which suction-holds the workpiece on a holding surface, the transport device comprising: a holding unit which holds the workpiece; a motor which generates power to move the holding unit towards or away from the holding surface; and a controller connected to the motor, the holding unit comprising: a support base; a suction section which is provided on the support base and connected to a suction source and which suction-holds the workpiece with a suction force generated by the suction source; and a pressing section which is provided on the support base and which presses the workpiece against the holding surface, the controller monitoring the torque of the motor when the workpiece is pressed against the holding surface by the pressing section.

[0012] Preferably, the controller moves the holding unit closer to the holding surface until a value corresponding to the torque of the motor reaches a predetermined reference value. Effect of the Invention

[0013] A conveying device according to one aspect of the present invention monitors the torque of a motor that generates power for pressing the workpiece against the holding surface when pressing the workpiece against the holding surface of a holding table to correct warpage of the workpiece. This makes it possible to stop pressing the workpiece against the holding surface at an appropriate time, and to properly convey the warped workpiece to the holding table. [Brief description of the drawings]

[0014] [Figure 1] FIG. [Diagram 2] 2 is a partial cross-sectional front view showing a transport device for transporting a workpiece. FIG. [Diagram 3] 1 is a partial cross-sectional front view showing the conveying device when a part of a workpiece is placed on a holding surface of a holding table. FIG. [Figure 4] 1 is a partial cross-sectional front view showing the conveying device when the entire workpiece is placed on the holding surface of the holding table. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a configuration example of a conveying device according to this embodiment will be described. Fig. 1 is a perspective view showing a conveying device 2. In Fig. 1, the X-axis direction (left-right direction, first horizontal direction) and the Y-axis direction (front-back direction, second horizontal direction) are perpendicular to each other and parallel to a horizontal plane. The Z-axis direction (up-down direction, height direction, vertical direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0016] The transport device 2 is mounted as a transport unit (transport mechanism) in a processing device that performs a predetermined process on a workpiece, and transports the workpiece within the processing device or between processing devices. Examples of processing devices on which the transport device 2 can be mounted include processing devices such as a cutting device that cuts the workpiece, a grinding device that grinds the workpiece, a polishing device that polishes the workpiece, and a laser processing device that performs laser processing on the workpiece.

[0017] The cutting device includes a holding table that holds the workpiece, and a processing unit (cutting unit) that cuts the workpiece. The cutting unit includes a spindle, and an annular cutting blade is attached to the tip of the spindle. The workpiece is held by the holding table, and the cutting blade is rotated while cutting into the workpiece, thereby cutting the workpiece.

[0018] The grinding device includes a holding table for holding the workpiece, and a processing unit (grinding unit) for grinding the workpiece. The grinding unit includes a spindle, and an annular grinding wheel including multiple grinding stones is attached to the tip of the spindle. The workpiece is held by the holding table, and the grinding stones are brought into contact with the workpiece while rotating the grinding wheel, thereby grinding the workpiece.

[0019] The polishing device includes a holding table for holding the workpiece and a processing unit (polishing unit) for polishing the workpiece. The polishing unit includes a spindle, and a disk-shaped polishing pad is attached to the tip of the spindle. The workpiece is held by the holding table, and the polishing pad is rotated and brought into contact with the workpiece, thereby polishing the workpiece.

[0020] The laser processing device includes a holding table (chuck table) for holding the workpiece, and a processing unit (laser irradiation unit) for performing laser processing on the workpiece. For example, the laser irradiation unit includes a laser oscillator that pulses a laser beam of a predetermined wavelength, and a condenser that condenses the laser beam emitted from the laser oscillator. The laser beam irradiated from the laser irradiation unit is condensed on the front, back, or inside of the workpiece, thereby performing laser processing on the workpiece.

[0021] The conveying device 2 can also be mounted on a processing device other than a processing device. For example, the conveying device 2 may be mounted on a cleaning device that cleans the workpiece, an inspection device that inspects the workpiece, etc. The cleaning device and the inspection device are also provided with a holding table that holds the workpiece.

[0022] The conveying device 2 holds and conveys the workpiece within or between the processing devices as described above. Specifically, the conveying device 2 conveys the workpiece from a predetermined location to a holding table, and also conveys the workpiece from the holding table to a predetermined location.

[0023] For example, the workpiece is a disk-shaped wafer made of a semiconductor material such as single crystal silicon. The wafer is divided into a plurality of rectangular regions by a plurality of streets (planned dividing lines) arranged in a lattice pattern so as to intersect with each other. In addition, devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices are formed in each of the regions divided by the streets.

[0024] A cutting device or a laser processing device is used to process the wafer and divide it along the streets to produce a plurality of device chips, each of which includes a device. Also, a grinding device or a polishing device is used to process and thin the wafer before division, to obtain thinned device chips.

[0025] However, there are no limitations on the type, material, size, shape, structure, etc. of the workpiece. For example, the workpiece may be a wafer (substrate) made of semiconductors other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramics, resin, metal, etc. In addition, there are no limitations on the type, number, shape, structure, size, arrangement, etc. of devices, and devices do not have to be formed on the workpiece.

[0026] Furthermore, the workpiece may be a package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) substrate. For example, a package substrate is formed by mounting a plurality of device chips on a predetermined substrate and covering and sealing the mounted device chips with a resin layer (mold resin). A cutting device or a laser processing device is used to divide and individualize the package substrate, thereby manufacturing a package device including a plurality of packaged device chips.

[0027] The transport device 2 includes a moving unit 4. The moving unit 4 includes a first moving mechanism (X-axis moving mechanism) 6 and a second moving mechanism (Z-axis moving mechanism) 18, and moves holding units 30A and 30B (described below) along the X-axis and Z-axis directions.

[0028] The first movement mechanism 6 includes a support structure 8. For example, the support structure 8 is formed in a rectangular parallelepiped shape, and the surface (front surface) of the support structure 8 is arranged along the XZ plane. On the surface side of the support structure 8, a pair of X-axis guide rails 10 arranged along the X-axis direction, and an X-axis ball screw 12 arranged along the X-axis direction between the pair of X-axis guide rails 10 are provided. In addition, a motor 14 that rotates the X-axis ball screw 12 is connected to an end of the X-axis ball screw 12.

[0029] An X-axis moving block 16 is attached to the pair of X-axis guide rails 10 so as to be slidable along the X-axis guide rails 10. For example, the X-axis moving block 16 is formed in a rectangular parallelepiped shape, and the surface (front surface) of the X-axis moving block 16 is disposed along the XZ plane. A nut portion (not shown) is provided on the back surface (rear surface) side of the X-axis moving block 16, and the X-axis ball screw 12 is screwed into this nut portion. When the X-axis ball screw 12 is rotated by the motor 14, the X-axis moving block 16 moves in the X-axis direction along the X-axis guide rails 10.

[0030] A second movement mechanism 18 is provided on the front surface side of the X-axis movement block 16. The second movement mechanism 18 includes a pair of Z-axis guide rails 20 arranged along the Z-axis direction, and a Z-axis ball screw 22 arranged along the Z-axis direction between the pair of Z-axis guide rails 20. In addition, a motor 24 that rotates the Z-axis ball screw 22 is connected to an end of the Z-axis ball screw 22.

[0031] A rectangular parallelepiped Z-axis moving block 26 is mounted on the pair of Z-axis guide rails 20 so as to be slidable along the Z-axis guide rails 20. A nut portion (not shown) is provided on the base end (rear end) side of the Z-axis moving block 26, and the Z-axis ball screw 22 is screwed into this nut portion. When the Z-axis ball screw 22 is rotated by the motor 24, the Z-axis moving block 26 moves along the Z-axis guide rails 20 in the Z-axis direction.

[0032] A pair of holding units 30A, 30B for holding a workpiece are attached to the tip (front end) of the Z-axis moving block 26. The first moving mechanism 6 and the second moving mechanism 18 control the movement of the holding units 30A, 30B. Specifically, when the motor 14 is operated, the X-axis ball screw 12 rotates, and the holding units 30A, 30B move along the X-axis direction by a distance corresponding to the number of rotations of the X-axis ball screw 12. When the motor 24 is operated, the Z-axis ball screw 22 rotates, and the holding units 30A, 30B move (raise and lower) along the Z-axis direction by a distance corresponding to the number of rotations of the Z-axis ball screw 22. This allows the holding units 30A, 30B to be positioned at a desired position.

[0033] A servo motor, a stepping motor (pulse motor), etc. can be used as the motors 14, 24. In particular, when a servo motor is used as the motors 14, 24, the movement of the holding units 30A, 30B can be controlled smoothly and with high precision even when a large load is applied to the holding units 30A, 30B during the transport of the workpiece.

[0034] The holding units 30A and 30B have the same configuration and are arranged in opposite directions. A rotation drive source (not shown) such as a motor is built into the Z-axis moving block 26, and the holding units 30A and 30B are attached to the Z-axis moving block 26 via the rotation drive source. When the rotation drive source is operated, the holding units 30A and 30B rotate around a rotation axis that is approximately parallel to the Y-axis direction. This allows the holding units 30A and 30B to be turned upside down.

[0035] The holding units 30A and 30B can hold the workpieces simultaneously. For example, one of the holding units 30A and 30B holds the workpiece being transported to the holding unit, and the other of the holding units 30A and 30B holds the workpiece being transported from the holding unit.

[0036] Next, a detailed description will be given of the configuration of the holding units 30A and 30B. Note that, although the configuration of the holding unit 30A will be described below, the configuration of the holding unit 30B is the same as that of the holding unit 30A.

[0037] The holding unit 30A includes a support base (main body) 32 that supports each of the components that make up the holding unit 30A. For example, the support base 32 is a rectangular parallelepiped member made of resin, metal, or the like, and includes a flat surface 32a facing the opposite side to the holding unit 30B. In addition, a rectangular recess 32b that opens to the surface 32a is provided on the surface 32a side of the support base 32.

[0038] The support base 32 is provided with a plurality of suction units 34 that suction-hold the workpiece. The plurality of suction units 34 are attached to the bottom surface of the recess 32b so as to be housed inside the recess 32b. Note that, although Fig. 1 shows an example in which 3 rows and 3 columns (total of 9 suction units 34) are arranged at predetermined intervals, there is no limit to the number and arrangement of the suction units 34, and they can be set appropriately depending on the size and shape of the workpiece.

[0039] The tip (one end) of the suction part 34 constitutes a suction surface 34a that comes into contact with the workpiece and holds the workpiece by suction. The base end (other end) of each of the plurality of suction parts 34 is connected to a flow path 36 constituted by piping such as a tube or a pipe via a flow path (not shown) formed inside the support base 32.

[0040] The flow passage 36 is connected to a suction source 40 such as an ejector via a valve 38A, and is connected to a gas supply source 42 via a valve 38B. The suction source 40 applies negative pressure to the plurality of suction parts 34 via the flow passage 36, thereby generating suction force for suctioning and holding the workpiece at the plurality of suction parts 34. The gas supply source 42 supplies gas such as air to the plurality of suction parts 34 via the flow passage 36.

[0041] The support base 32 is also provided with a plurality of pressing parts 44 that press the workpiece against the holding surface of the holding unit when the workpiece is transported to the holding unit. For example, the support base 32 is a plate-like member formed in a rectangular shape, and the four pressing parts 44 are fixed so as to fit along the four side surfaces of the recess 32b.

[0042] There is no limitation on the material of the pressing part 44 as long as it can press the workpiece. For example, a member made of a flexible elastic body such as resin or rubber is used as the pressing part 44. The pressing part 44 may be formed separately from the support base 32 and then fixed to the support base 32 via an adhesive or the like, or may be formed integrally with the support base 32.

[0043] The tip surface (upper surface in FIG. 1) of the pressing portion 44 constitutes a pressing surface 44a that comes into contact with the workpiece and presses the workpiece. The height of the pressing portion 44 is greater than the depth of the recess 32b. Therefore, the pressing surface 44a side of the pressing portion 44 is disposed so as to protrude from the surface 32a of the support base 32.

[0044] Furthermore, the transfer device 2 includes a controller (control unit, control section, control device) 46 that controls the transfer device 2. The controller 46 is connected to each component of the transfer device 2 (motors 14, 24, a rotation drive source that rotates the holding units 30A, 30B, valves 38A, 38B, suction source 40, gas supply source 42, etc.). The controller 46 outputs control signals to the components of the transfer device 2 to control the holding and transfer of the workpiece by the transfer device 2.

[0045] For example, the controller 46 is configured by a computer and includes a processing unit that executes processing such as calculations necessary for transporting the workpiece, and a storage unit that stores various information (data, programs, etc.) used in processing by the processing unit. The processing unit includes a processor such as a CPU (Central Processing Unit), and the storage unit includes memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory). If the processing device on which the transport device 2 is mounted is equipped with a controller, the controller of the processing device may also serve as the controller 46.

[0046] Fig. 2 is a partially sectional front view showing the transport device 2 transporting the workpiece 11. For simplification, the first moving mechanism 6 and the holding unit 30B are omitted from Fig. 2. Fig. 2 also shows a state in which the holding unit 30A is arranged so that the surface 32a of the support base 32, the suction surface 34a of the suction unit 34, and the pressing surface 44a of the pressing unit 44 face downward.

[0047] For example, the workpiece 11 is a disk-shaped wafer or a rectangular package substrate, and has a first surface 11a and a second surface 11b that are generally parallel to each other. The workpiece 11 also has warpage that occurs during its manufacturing or processing process. For example, when a disk-shaped wafer is subjected to a heat treatment or a thinning treatment, the outer periphery of the wafer may be deformed so as to warp upward. In addition, when manufacturing a package substrate, if the resin layer is cooled after a heat treatment for hardening the resin layer, the resin layer may shrink, causing warpage in the package substrate.

[0048] 2 shows the workpiece 11 warped so that the entire workpiece is curved in a downward convex shape. That is, the first surface 11a of the workpiece 11 is curved in a concave curved shape, the second surface 11b is curved in a convex curved shape, and the outer periphery is deformed so that it is warped upward. The holding unit 30A sucks and holds the warped workpiece 11 with a plurality of suction parts 34.

[0049] For example, the suction unit 34 includes a suction pad 50 that sucks the workpiece 11, and a columnar rod 52 connected to the suction pad 50. For example, the suction pad 50 is made of a flexible elastic body such as rubber, and is formed in a dome shape with a hollow inside. The tip surface of the suction pad 50 corresponds to the suction surface 34a of the suction unit 34, and a tip portion of the rod 52 is fixed to the base end side of the suction pad 50. In addition, the base end portion of the rod 52 is inserted into an insertion hole (not shown) provided in the bottom of the recess 32b of the support base 32, and the rod 52 is supported so as to be movable along the thickness direction of the support base 32 (the Z-axis direction in FIG. 2).

[0050] A biasing member 54 that biases the suction pad 50 is fixed to the suction pad 50. An elastic member such as a spring that can be elastically deformed can be used as the biasing member 54. For example, when the biasing member 54 is a coil spring, the coil spring is attached so as to surround the rod 52. One end of the coil spring is fixed to the suction pad 50, and the other end of the coil spring is fixed to the bottom surface of the recess 32b of the support base 32.

[0051] The suction pad 50 is urged toward the outside of the support base 32 by the urging member 54. When no external force is acting on the suction pad 50, the tip surface (suction surface 34a) of the suction pad 50 is positioned at a position farther from the surface 32a of the support base 32 than the pressing surface 44a of the pressing portion 44. In other words, the amount of protrusion of the suction portion 34 from the surface 32a is greater than the amount of protrusion of the pressing portion 44 from the surface 32a.

[0052] On the other hand, when an external force toward the support base 32 is applied to the suction pad 50, the biasing member 54 contracts and the suction pad 50 approaches the support base 32. As a result, the tip surface (suction surface 34a) of the suction pad 50 is positioned on the same plane as the pressing surface 44a of the pressing portion 44 or closer to the support base 32 than the pressing surface 44a. In other words, the amount of protrusion of the suction portion 34 from the surface 32a becomes equal to or less than the amount of protrusion of the pressing portion 44 from the surface 32a.

[0053] The above-mentioned conveying device 2 conveys the workpiece 11 to a holding table (chuck table) 60. The holding table 60 is mounted on the above-mentioned processing device (processing device, cleaning device, inspection device, etc.) together with the conveying device 2, and holds the workpiece 11 to be subjected to a predetermined process.

[0054] The holding table 60 includes a cylindrical frame (main body) 62 made of metal such as SUS (stainless steel), glass, ceramics, resin, or the like. A recess 62b is provided in the center of the upper surface 62a side of the frame 62, and a holding member 64 made of a porous material such as porous ceramics is fitted into the recess 62b. The holding member 64 includes a large number of pores that communicate from the upper surface to the lower surface of the holding member 64. The upper surface of the holding member 64 forms a suction surface 64a that sucks the workpiece 11 when the workpiece 11 is held by the holding table 60.

[0055] The shapes of the recess 62b and the holding member 64 are appropriately set according to the shape of the workpiece 11. For example, if the workpiece 11 is a disk-shaped wafer, the recess 62b and the holding member 64 can be formed in a circular shape. If the workpiece 11 is a rectangular package substrate, the recess 62b and the holding member 64 can be formed in a rectangular shape. The dimensions of the recess 62b and the holding member 64 are set so that the workpiece 11 can cover the entire suction surface 64a.

[0056] A holding surface 60a for holding the workpiece 11 is configured by an upper surface 62a of the frame 62 and a suction surface 64a of the holding member 64. The holding surface 60a is connected to a suction source 68 such as an ejector via a pore included in the holding member 64, a flow path 62c provided inside the frame 62, and a valve 66.

[0057] A moving unit (not shown) that moves the holding table 60 and a rotary drive source (not shown) that rotates the holding table 60 are connected to the holding table 60. The moving unit is configured, for example, by a ball screw type moving mechanism, and moves the holding table 60 along the XY plane. The rotary drive source is configured, for example, by a motor, and rotates the holding table 60 around a rotation axis that is approximately parallel to the Z-axis direction.

[0058] The operation of the transfer device 2 when transferring the workpiece 11 to the holding table 60 is controlled by the controller 46. A block diagram showing the functional configuration of the controller 46 is shown in FIG.

[0059] In this embodiment, when the workpiece 11 is placed on the holding surface 60a of the holding table 60, the controller 46 controls the motor 24 and monitors the torque of the motor 24. Specifically, the controller 46 includes a motor control unit 46a that controls the motor 24, and a monitoring unit 46b that monitors the torque of the motor 24. The controller 46 also includes a storage unit 46c that stores various information (data, programs, etc.) used in the processing in the motor control unit 46a and the monitoring unit 46b.

[0060] The motor control unit 46a outputs a control signal to the motor 24 to control the rotation direction, number of rotations, and rotation speed of the Z-axis ball screw 22. As a result, the Z-axis moving block 26 and the holding units 30A, 30B connected to the Z-axis moving block 26 move up and down a predetermined distance at a predetermined speed along the Z-axis direction. In other words, the motor 24 generates power to move the holding units 30A, 30B toward or away from the holding surface 60a of the holding table 60.

[0061] Furthermore, while the motor 24 is being driven, a value corresponding to the torque of the motor 24 (torque corresponding value) is input to the monitoring unit 46b or calculated by the monitoring unit 46b. The torque corresponding value may be the value of the torque applied to the rotating shaft of the motor 24, or may be another value corresponding to the torque applied to the rotating shaft of the motor 24. For example, when the torque applied to the rotating shaft of the motor 24 changes, the current value of the motor 24 required to maintain the rotation speed of the rotating shaft also changes. Therefore, the current value of the motor 24 can also be used as the torque corresponding value.

[0062] For example, the torque corresponding value is measured by a sensor built into or connected to the motor 24 and input to the monitoring unit 46b. The monitoring unit 46b may also calculate the torque corresponding value based on a signal input from the motor 24. In this way, the torque corresponding value of the motor 24 is sequentially acquired in real time by the monitoring unit 46b.

[0063] The monitoring unit 46b also monitors changes in the torque of the motor 24 based on the torque corresponding value. Specifically, a reference value corresponding to an upper limit of the torque corresponding value is stored in advance in the storage unit 46c. The monitoring unit 46b then compares the torque corresponding value of the motor 24 with the reference value read from the storage unit 46c to determine whether the torque corresponding value of the motor 24 has reached the reference value.

[0064] The result of monitoring (determination) by the monitoring unit 46b is output to the motor control unit 46a. Then, the motor control unit 46a outputs a control signal to the motor 24 based on the monitoring result (determination result). This makes it possible to control the operation of the motor 24 based on the torque of the motor 24.

[0065] Next, a specific example of a method for transporting a warped workpiece 11 to a holding unit will be described using the transport device 2. Note that, although the following describes a case where the workpiece 11 is held by the holding unit 30A as an example, the workpiece 11 may be held by the holding unit 30B.

[0066] When the workpiece 11 is transported, the workpiece 11 is first sucked and held by the multiple suction parts 34 provided in the holding unit 30A. Specifically, the rotation angle of the holding unit 30A is adjusted so that the suction surfaces 34a of the multiple suction parts 34 provided in the holding unit 30A face downward. The workpiece 11 is placed at a predetermined position, which is the source of transport. Then, with the suction surfaces 34a of the multiple suction parts 34 in contact with the first surface 11a of the workpiece 11, the valve 38A is opened to apply the suction force (negative pressure) of the suction source 40 to the suction surface 34a. As a result, the workpiece 11 is sucked and held by the holding unit 30A with the first surface 11a facing upward and the second surface 11b facing downward.

[0067] As described above, the plurality of suction units 34 are configured to be movable in the thickness direction of the support base 32 (the Z-axis direction in FIG. 2). When the suction pad 50 comes into contact with the workpiece 11, the height position of the suction pad 50 is adjusted according to the height position of the first surface 11a of the workpiece 11 by the expansion and contraction of the biasing member 54. This allows the suction surfaces 34a of the plurality of suction units 34 to come into contact with the first surface 11a of the workpiece 11, respectively, even if the workpiece 11 is warped and the first surface 11a is not flat.

[0068] Next, the holding unit 30A is moved by the first moving mechanism 6 and the second moving mechanism 18, and the holding unit 30A is disposed directly above the holding table 60 as shown in Fig. 2. As a result, the workpiece 11 is positioned so as to overlap with the holding surface 60a of the holding table 60 in the Z-axis direction.

[0069] Next, a control signal is output from the motor control unit 46a to the motor 24, and the motor 24 rotates the Z-axis ball screw 22 so that the Z-axis moving block 26 descends. This causes the holding unit 30A to descend, and the workpiece 11 approaches the holding surface 60a of the holding table 60. In addition, the valve 66 is opened to apply the suction force (negative pressure) of the suction source 40 to the holding surface 60a (suction surface 64a) of the holding table 60.

[0070] During the descent of the holding unit 30A, the monitoring unit 46b monitors the torque of the motor 24. Specifically, the monitoring unit 46b sequentially compares the torque corresponding value of the motor 24 with a reference value stored in the memory unit 46c in real time.

[0071] 3 is a partial cross-sectional front view showing the conveying device 2 when a part of the workpiece 11 is placed on the holding surface 60a of the holding table 60. When the holding unit 30A is lowered to a predetermined position, the second surface 11b side of the central part of the workpiece 11 reaches and comes into contact with the suction surface 64a of the holding table 60. As a result, the central part of the workpiece 11 is sucked by the suction surface 64a.

[0072] However, since the workpiece 11 has a curved outer periphery, even when the center of the workpiece 11 reaches the holding surface 60a, the outer periphery of the workpiece 11 does not come into contact with the suction surface 64a. That is, at the outer periphery of the workpiece 11, a gap exists between the second surface 11b of the workpiece 11 and the suction surface 64a. Then, the suction force acting on the suction surface 64a leaks from the gap. Therefore, at the stage where only the center of the workpiece 11 reaches the holding surface 60a, the workpiece 11 is not completely suction-held by the holding table 60.

[0073] Furthermore, when the workpiece 11 comes into contact with the holding surface 60a, the workpiece 11 is supported from below by the holding surface 60a, and the torque of the motor 24 generating the power to lower the holding unit 30A increases. However, at the stage where only the center of the workpiece 11 comes into contact with the holding surface 60a, the outer periphery of the workpiece 11 is not yet supported by the holding surface 60a, and the torque response value of the motor 24 does not reach the reference value.

[0074] 4 is a partial cross-sectional front view showing the conveying device 2 when the entire workpiece 11 is placed on the holding surface 60a of the holding table 60. When the holding unit 30A is further lowered after the center of the workpiece 11 reaches the holding surface 60a, the pressing surfaces 44a of the multiple pressing parts 44 come into contact with the outer periphery of the workpiece 11 and press the outer periphery of the workpiece 11 against the holding surface 60a. This causes the workpiece 11 to deform so as to eliminate the warp.

[0075] When the pressing portion 44 is pressed against the outer periphery of the workpiece 11, the biasing member 54 contracts as the support base 32 descends, narrowing the distance between the support base 32 and the suction pad 50. This makes it possible to prevent the suction portion 34 from interfering with the pressing of the workpiece 11 by the pressing portion 44.

[0076] When the outer periphery of the workpiece 11 is pressed against the pressing surface 44a and the entire second surface 11b side of the workpiece 11 comes into contact with the holding surface 60a, the workpiece 11 is deformed so as to become flat along the holding surface 60a, and the warpage of the workpiece 11 is corrected. In addition, the gap between the outer periphery of the workpiece 11 and the suction surface 64a disappears, and the suction surface 64a is entirely covered by the workpiece 11. This prevents leakage of the suction force acting on the suction surface 64a, and the workpiece 11 is reliably suction-held by the holding table 60.

[0077] Here, the controller 46 moves the holding unit 30A closer to the holding surface 60a until the torque correspondence value of the motor 24 reaches the reference value. Specifically, when the entire second surface 11b side of the workpiece 11 contacts the holding surface 60a, the workpiece 11 does not deform any more, and the load on the pressing unit 44 increases rapidly. As a result, the torque of the motor 24 generating the power to lower the holding unit 30A also increases rapidly, and the torque correspondence value of the motor 24 monitored by the monitoring unit 46b reaches the reference value. In other words, the reference value is set to a value equivalent to the torque correspondence value of the motor 24 when the entire workpiece 11 reaches the holding surface 60a.

[0078] When the entire workpiece 11 is held by the holding surface 60a and the torque corresponding value reaches the reference value, the monitoring unit 46b outputs a signal (arrival signal) to the motor control unit 46a indicating that the torque corresponding value has reached the reference value. Then, the motor control unit 46a, to which the arrival signal has been input, outputs a control signal to the motor 24 to stop the rotation of the Z-axis ball screw 22. This allows the descent of the holding unit 30A to be stopped in a timely manner at the timing when the workpiece 11 is sucked and held by the holding table 60. As a result, the workpiece 11 is securely held by the holding table 60, and damage to the workpiece 11 due to excessive pressing by the pressing unit 44 is avoided.

[0079] Then, after the descent of the holding unit 30A is stopped, the controller 46 closes the valve 38A and opens the valve 38B. This causes gas such as air to be supplied from the gas supply source 42 to the suction pad 50, and the suction and holding of the workpiece 11 by the suction unit 34 is released. Since the entire workpiece 11 is suction-held by the holding table 60, the warp of the workpiece 11 is maintained in a straightened state even when the suction of the workpiece 11 by the suction unit 34 is released. In this manner, the transfer of the workpiece 11 to the holding table 60 is completed.

[0080] Thereafter, the holding unit 30A is raised by the power of the motor 24, and the suction part 34 moves away from the workpiece 11. Then, the holding table 60 holding the workpiece 11 moves to a processing chamber or the like where a predetermined processing is performed on the workpiece 11.

[0081] As described above, the conveying device 2 according to this embodiment monitors the torque of the motor 24 that generates the power for pressing the workpiece 11 against the holding surface 60a when pressing the workpiece 11 against the holding surface 60a of the holding table 60 to correct the warpage of the workpiece 11. This makes it possible to stop pressing the workpiece 11 against the holding surface 60a at an appropriate time, and to properly convey the warped workpiece 11 to the holding table 60.

[0082] Although the above describes the case where the workpiece 11 is transported to the holding table 60 by the holding unit 30A, the holding unit 30B (see FIG. 1) can also be used to transport the workpiece 11. In this case, the rotation angle of the holding unit 30B is adjusted so that the multiple suction parts 34 provided in the holding unit 30B face downward. Then, the workpiece 11 is transported to the holding table 60 by the holding unit 30B in the same procedure as when the workpiece 11 is transported by the holding unit 30A.

[0083] The holding units 30A and 30B can also be used when transporting the workpiece 11 from the holding table 60. Specifically, after the workpiece 11 is subjected to a predetermined process, the holding table 60 is placed directly below the holding units 30A and 30B. Next, the motor 24 lowers the holding units 30A and 30B, and the suction surfaces 34a of the multiple suction parts 34 provided in the holding unit 30A or the holding unit 30B are brought into contact with the first surface 11a of the workpiece 11. Then, the valve 38A is opened to apply the suction force of the suction source 40 to the suction surface 34a. As a result, the workpiece 11 is suction-held by the multiple suction parts 34.

[0084] Next, the valve 66 is closed, and the suction holding of the workpiece 11 by the holding table 60 is released. Thereafter, the motor 24 rotates the Z-axis ball screw 22 to raise the holding units 30A and 30B, thereby releasing the workpiece 11 from the holding table 60. In this manner, the workpiece 11 is transported from the holding table 60 by the holding units 30A and 30B.

[0085] Furthermore, the workpiece 11 held by the holding table 60 can be replaced by the holding units 30A and 30B. Specifically, in a state where the processed workpiece 11 is placed on the holding table 60, a new workpiece 11 to be transported onto the holding table 60 is held by one of the holding units 30A and 30B. Then, the processed workpiece 11 is held by the other of the holding units 30A and 30B and removed from the holding table 60, and then the holding units 30A and 30B are turned upside down, and the workpiece 11 held by one of the holding units 30A and 30B is placed on the holding table 60. This allows the workpiece 11 to be transported to the holding table 60 and the workpiece 11 to be transported from the holding table 60 continuously, improving the transport efficiency.

[0086] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0087] 11 Workpiece 11a 1st page 11b Side 2 2. Conveyor device 4 Mobile Units 6 1st movement mechanism (X-axis movement mechanism) 8 Support structure 10 X-axis guide rail 12 X-axis ball screw 14 Motor 16 X-axis moving block 18 Second movement mechanism (Z-axis movement mechanism) 20 Z-axis guide rail 22 Z-axis ball screw 24 Motor 26 Z-axis moving block 30A, 30B holding unit 32 Support base (main body) 32a surface 32b Recess 34 Suction part 34a Suction surface 36 Flow Path 38A, 38B Valve 40 Suction source 42 Gas supply source 44 Pressing part 44a Pressing surface 46 Controller (control unit, control section, control device) 46a Motor control unit 46b Monitoring Department 46c storage section 50 Suction Pads 52 Rod 54 Pressing member 60 Holding table (chuck table) 60a Retaining surface 62 Frame (main body) 62a top surface 62b Recess 62c Flow Path 64 Retaining member 64a Suction surface 66 Valve 68 Suction source

Claims

1. A conveying device that conveys a warped workpiece to a holding table that holds the workpiece by suction with a holding surface, A holding unit for holding the workpiece; A motor that generates power to move the holding unit toward or away from the holding surface; a controller connected to the motor, The holding unit comprises: A support base; a suction unit provided on the support base and connected to a suction source for suction-holding the workpiece by a suction force generated by the suction source; a pressing portion provided on the support base and pressing the workpiece against the holding surface; The controller A conveying apparatus comprising: a conveying unit that monitors a torque of the motor when the workpiece is pressed against the holding surface by the pressing portion.

2. 2. The transport device according to claim 1, wherein the controller moves the holding unit closer to the holding surface until a value corresponding to a torque of the motor reaches a predetermined reference value.

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