Transportation method

Abstract

This invention provides a transport method that enables the precise holding and transport of objects to be transported. [Solution] This is a transport method in which one side (111) of a transport object (11) is held by a holding part (10), and the other side (112) is held by a transport part (21) for transport. The method includes sensors (30, 40) that detect the load applied to at least one of the holding part and the transport part. A target load is set to be applied when the transport part holds the transport object held by the holding part, and the transport part is pressed relative to the transport object held by the holding part until the load detected by the sensors reaches the target load, causing the transport part to hold the transport object, and the transport part then performs an operation to unload the transport object from the holding part.

Description

Technical Field

[0004]

[0001] The present invention relates to a conveying method for conveying an object to be conveyed.

Background Art

[0002] A conveying mechanism for loading and unloading an object to be conveyed with respect to the holding surface of a holding unit needs to appropriately hold the object to be conveyed on a conveying unit (such as a conveying pad that sucks and holds the object to be conveyed). When holding, if the conveying unit is pressed too strongly against the object to be conveyed, there is a risk of damaging the object to be conveyed. Conversely, if the pressing force of the conveying unit against the object to be conveyed is insufficient, there is a risk that the object to be conveyed cannot be held during conveyance and will fall off.

[0003] In the method disclosed in Patent Document 1, the torque of a motor that raises and lowers the conveying unit is monitored, and when the torque exceeds a threshold value, it is determined that the conveying unit has been pressed against the object to be conveyed, enabling automatic management of the pressing force of the conveying unit. <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​One aspect of the present invention is a transport method for transporting an object, in which one side of the object is held by a holding part and the other side is held by a transport part, the method comprising a sensor for detecting the load applied to at least one of the holding part and the transport part, setting a target load to be applied when the transport part holds the object held by the holding part, pressing the transport part relative to the object held by the holding part until the load detected by the sensor reaches the target load, causing the transport part to hold the object, and then performing a transport operation to unload the object from the holding part.

[0008] One aspect of the present invention is a transport method for transporting an object, in which one side of the object is held by a holding unit and the other side of the object is held by a transport unit, the method comprising a sensor for detecting the load applied to at least one of the holding unit and the transport unit, setting a target load to be applied when the transport unit holds the object held by the holding unit, recording the relative target position of the transport unit with respect to the holding unit when the target load is reached, causing the transport unit to hold the object based on the target position, and performing an operation to discharge the object from the holding unit by the transport unit.

[0009] It is preferable to provide a plurality of the sensors in a planar direction along one or the other surface of the object to be conveyed.

[0010] When setting the target load, it is preferable that the holding unit holds a setting workpiece whose contact area with the conveying unit is the same as that of the object to be conveyed, and that the conveying unit detects a load that allows the setting workpiece to be held.

[0011] The transport unit preferably holds the object to be transported by suction. [Effects of the Invention]

[0012] According to the conveying method of the present invention, a sensor detects the load applied to at least one of the holding section and the conveying section to set an appropriate target load, and the conveying section is pressed until the target load is reached, or a target position corresponding to the target load is used as a reference to cause the conveying section to hold the object to be conveyed, and the conveying section then performs an operation to release the object to be conveyed from the holding section, thereby enabling the conveying section to hold and convey the object to be conveyed with high precision. [Brief explanation of the drawing]

[0013] [Figure 1] This is a side view of a holding table and transport mechanism with a load sensor positioned on the transport pad side. [Figure 2] This is a plan view showing the arrangement of load sensors on a transport pad or holding table. [Figure 3] This is a side view of a holding table and transport mechanism in a configuration where a load sensor is positioned on the holding table side. [Modes for carrying out the invention]

[0014] The holding table 10 shown in Figure 1 constitutes the holding unit in the transport method of this disclosure and is provided in the processing device that processes the object to be transported 11. The processing performed on the object to be transported 11 by the processing device includes various processes such as grinding, polishing, cutting, laser processing, and plasma processing, as well as cleaning, tape application, inspection, and imaging. The processing unit that performs these processes is not shown in the illustration. The processing device may perform processes other than those described above.

[0015] The transport object 11 can be various types of wafers, such as silicon wafers, or package substrates. The material and shape of the transport object 11 are not limited, but the transport method of this disclosure is particularly useful when the transport object 11 is a thin, plate-like object that may be damaged if subjected to strong pressure.

[0016] The holding table 10 is constructed by attaching a porous plate 13 made of a porous material to the upper side of a frame 12. Through a flow path 14 communicating with the porous plate 13, a suction force is applied to the porous plate 13 from a suction source 15, making it possible to suction and hold the object to be transported 11 on the holding surface 16 of the holding table 10. Alternatively, the structure may be designed to apply suction force by forming suction holes or suction grooves on the holding surface 16 without providing a porous plate 13. When processing the object to be transported 11 with the processing device, one side of the object to be transported, the lower surface 111, is placed on the holding surface 16 of the holding table 10, and the suction source 15 is operated to suction and hold the object to be transported 11 on the holding surface 16.

[0017] The frame 12 of the holding table 10 is supported by a base 17. When the object to be transported 11 is to be moved or rotated horizontally, the base 17 is movably supported relative to the base of the processing device by a horizontal movement mechanism and a rotation mechanism (not shown), and the holding table 10 moves or rotates via the base 17. The horizontal movement mechanism for moving the base 17 is, for example, a ball screw mechanism equipped with a ball screw that extends horizontally and screws into the base 17, and the ball screw is rotated by a motor to impart a horizontal movement force to the base 17. The rotation mechanism for rotating the base 17 is, for example, a mechanism that rotatably supports a rotation shaft that extends vertically and connects to the base 17, and the rotation shaft is driven by a motor to rotate it. The holding table 10 may also be fixed without rotating or moving.

[0018] The transport mechanism 20 for loading and unloading the transport object 11 onto the holding table 10 comprises a transport pad 21 and a transport arm 22, which constitute the transport section in the transport method of this disclosure. The transport pad 21 is attached to the tip of the transport arm 22. The transport pad 21 and the transport arm 22 are moved horizontally by a horizontal movement mechanism 23 and vertically by a lifting mechanism 24.

[0019] The horizontal movement mechanism 23 is provided with a guide rail 232 extending in the horizontal direction on a column 231 fixed to the base of the processing device, and supports a horizontal movement table 233 so as to be movable in the horizontal direction along the guide rail 232. A ball screw 234 extending in the horizontal direction is screwed into the nut portion of the horizontal movement table 233. When the ball screw 234 is rotated by a motor 235, the horizontal movement table 233 moves in the horizontal direction along the guide rail 232.

[0020] The lifting mechanism 24 is constituted by a ball screw mechanism that rotates a ball screw 241 extending in the vertical direction by a motor 242 to apply a vertical movement force to the transfer arm 22. A guide rail 243 extending in the vertical direction is provided on the horizontal movement table 233, and the transfer arm 22 is supported so as to be movable in the vertical direction by the guide rail 243. The ball screw 241 is screwed into the nut portion of the transfer arm 22. When the motor 242 is operated to rotate the ball screw 241, the transfer arm 22 moves in the vertical direction along the guide rail 243. The rotation angle of the motor 242 is detected by an encoder 244 and transmitted to a control unit 31 that controls the operation of the transfer mechanism 20. The control unit 31 controls the operation of the motor 242 based on the signal input from the encoder 244. Note that the lifting mechanism 24 may be constituted by an air cylinder mechanism or the like that moves a piston in the vertical direction by the force of air with respect to the cylinder.

[0021] A plurality of suction pads 25 are provided on the lower surface side of the transfer pad 21. It is possible to apply a suction force from a suction source 27 to the suction pads 25 through a flow path 26 communicating with the suction pads 25. When the transfer mechanism 20 transfers the transfer object 11, the suction source 27 is operated to make the suction force act on the suction pads 25, and the suction pads 25 of the transfer pad 21 are pressed against the upper surface 112 which is the other surface of the transfer object 11, so that the transfer object 11 is sucked and held below the transfer pad 21.

[0022] When loading the object 11 to be conveyed onto the holding table 10, the suction source 27 is operated to hold the upper surface 112 of the object 11 to be conveyed by the suction pad 25 in a suction - held state. Then, the horizontal movement mechanism 23 moves the conveyance pad 21 above the holding table 10, and the lifting mechanism 24 lowers the conveyance pad 21 to place the lower surface 111 of the object 11 to be conveyed on the holding surface 16. The suction source 15 is operated to apply a suction force to the holding surface 16, and at the same time, the operation of the suction source 27 is stopped to release the suction force acting on the suction pad 25. As a result, the object 11 held on the conveyance pad 21 side separates from the suction pad 25, and the lower surface 111 of the object 11 adheres closely to the holding surface 16 and is suction - held on the holding table 10 side.

[0023] When unloading the object 11 held on the holding table 10, the horizontal movement mechanism 23 moves the conveyance pad 21 above the holding table 10, and the lifting mechanism 24 lowers the conveyance pad 21 to press the suction pad 25 against the upper surface 112 of the object 11 to be conveyed. Also, the suction source 27 is operated to apply a suction force to the suction pad 25. Before pressing the suction pad 25 against the upper surface 112 of the object 11 to be conveyed, the suction force may be applied to the suction pad 25. On the holding table 10, the suction force acting from the suction source 15 on the holding surface 16 is released. As a result, the object 11 held on the holding table 10 side separates from the holding surface 16, and the object 11 to be conveyed is suction - held on the conveyance pad 21 side via the suction pad 25.

[0024] In this way, when performing conveyance by the conveyance mechanism 20 in a form where the conveyance pad 21 sucks and holds the opposite upper surface 112 side of the object 11 to be conveyed whose lower surface 111 side is held by the holding table 10, by pressing the suction pad 25 provided on the conveyance pad 21 against the object 11 to be conveyed, the suction force of the suction pad 25 acts on the object 11 to be conveyed. That is, when transferring the object 11 to be conveyed from the holding table 10 to the conveyance pad 21, it is necessary to lower the conveyance pad 21 by the lifting mechanism 24 until the suction force from the suction pad 25 acts reliably on the object 11 to be conveyed.

[0025] If, in order to prioritize securely holding the object to be transported 11, the lifting mechanism 24 is controlled to lower the transport pad 21 excessively, the pressing force applied by the suction pad 25 of the transport pad 21 against the object to be transported 11 may become excessive. Pressing the object to be transported 11 with excessive force may cause it to break. In particular, if the object to be transported 11 is thin or made of a fragile material, the risk of breakage is high, so the force applied by the transport pad 21 must be carefully controlled.

[0026] Conversely, if the operation control is set to reduce the amount the transport pad 21 is lowered by the lifting mechanism 24 in order to avoid placing a large load on the transport object 11, the force pressing the suction pad 25 against the upper surface 112 of the transport object 11 will be insufficient, the suction pad 25 will not adhere closely to the upper surface 112 of the transport object 11, the suction force from the suction pad 25 will leak, and there is a risk that the transport object 11 will not be properly held by suction.

[0027] Therefore, when transporting the object 11 held on the holding table 10 by the transport mechanism 20, it is necessary to precisely control the amount of downward movement of the transport pad 21 to transfer the object 11 to the transport pad 21. Due to factors such as the individual differences in the thickness of the objects 11, the possibility of warping of the objects 11 causing variations in the height of the top surface 112, and the change in the height position of the holding surface 16 on the holding table 10 due to self-grinding, which grinds the porous plate 13 to adjust the surface shape of the holding surface 16, the optimal height position of the transport pad 21 when holding the object 11 is not uniform. For this reason, conventionally, when holding the object 11 on the transport pad 21, the operator would visually check the height of the transport pad 21 and the transport arm 22 while observing the change in the vacuum pressure for suction to manage the appropriate pressing force, but this was prone to human error and time-consuming.

[0028] Alternatively, as described in Patent Document 1 above, a method is known in which the torque of the motor 242 of the lifting mechanism 24 that raises and lowers the transport pad 21 is monitored and the pressing force of the transport pad 21 against the object to be transported 11 is automatically controlled. Specifically, when attempting to lower the transport pad 21 while the suction pad 25 is in contact with the object to be transported 11, resistance is applied to the movement of the transport pad 21, causing the torque of the motor 242 of the lifting mechanism 24 to increase. This torque is set as a threshold, and when the torque of the motor 242 detected when the transport pad 21 is lowering exceeds the threshold, it is determined that the transport pad 21 is being pressed against the object to be transported 11, and the lowering of the transport pad 21 is controlled to stop.

[0029] However, in the lifting mechanism 24, the torque of the motor 242 tends to be large in order to drive the heavy transport pad 21 and transport arm 22, making it difficult to obtain minute changes in pressing force based on changes in the torque of the motor 242. In other words, determining the load based on changes in the torque of the motor 242 was not always suitable as a method for controlling the position of the transport pad 21, which requires adjustment of minute pressing forces. Furthermore, the torque of the motor 242 may change due to aging deterioration of the components of the lifting mechanism 24 or fluctuations in operating resistance, which may cause detection errors due to reasons other than the pressing state of the transport pad 21 against the transported object 11.

[0030] Thus, in conventional conveying methods, there is a problem in that it is difficult to control and manage the lowering of the conveying pad 21 to achieve an appropriate pressing force when holding the object to be conveyed 11 with the conveying pad 21, and a solution to this problem has been sought. The conveying method of this disclosure presses the conveying pad 21 against the object to be conveyed 11 with an optimal pressing force, thereby preventing damage to the object to be conveyed 11 and achieving high-precision conveying.

[0031] In this embodiment, the transport mechanism 20 has a structure in which multiple suction pads 25 are arranged on the lower side of the transport pad 21. However, the transport pad 21 may also have a structure in which a wide suction surface made of a porous plate is provided on the lower side of the transport pad 21. Even in the case of a transport pad 21 with such a structure, when the transport object 11 held on the holding table 10 is held by the transport pad 21 by suction, it is necessary to lower the transport pad 21 and press the suction surface of the transport pad 21 against the upper surface 112 of the transport object 11, so the same problem exists. In other words, in the transport method of this disclosure, the configuration of the transport pad 21 for holding the transport object 11 is not limited, and any configuration that performs an action of pressing the transport pad 21 against the transport object 11 when holding is applicable.

[0032] As shown in Figure 1, the transport pad 21 is equipped with an intermediate support member 28 that supports multiple suction pads 25, and a load sensor 30 is provided between the main body 29 of the transport pad 21 and the intermediate support member 28. Multiple load sensors 30 are arranged at different positions in the horizontal direction (in a planar direction parallel to the lower surface 111 and upper surface 112 of the object to be transported 11). For example, as shown in Figure 2, three load sensors 30 are arranged at approximately equal intervals (120° intervals) in the circumferential direction of the disc-shaped transport pad 21. Each load sensor 30 uses a piezoelectric sensor that detects the charge when a piezoelectric element elastically deforms due to a load, or a strain gauge sensor that detects the change in electrical resistance when a strain gauge deforms due to a load, making it possible to detect changes in the vertical load acting on the intermediate support member 28 via the suction pads 25. The detection signals from the load sensors 30 are transmitted to a control unit 31 that controls the operation of the transport mechanism 20.

[0033] A first embodiment of the transport method of this disclosure will now be described. First, a setting step is performed to set a target load to be applied when the transport pad 21 holds the transport object 11 held on the holding table 10. The setting step is performed by holding a setting workpiece (dummy workpiece) that covers the holding surface 16 of the holding table 10 on the holding table 10. The setting workpiece satisfies the condition that at least the contact area with the transport pad 21 is the same as that of the transport object 11, and it is preferable that its thickness is also the same as that of the transport object 11. In this embodiment, it is required that all of the suction pads 25 provided on the transport pad 21 can be pressed against the setting workpiece. Note that the shape of the setting workpiece may differ from that of the transport object 11 as long as this condition is met. For example, if the transport object 11 is circular in plan view, the setting workpiece may be rectangular in plan view.

[0034] With the setting workpiece held on the holding surface 16 of the holding table 10, the suction source 27 is activated to apply suction force to the suction pad 25, the motor 242 of the lifting mechanism 24 is activated to lower the transport pad 21 and press the suction pad 25 against the setting workpiece, and then the transport pad 21 is raised. This operation is performed in stages multiple times, varying the amount the transport pad 21 is lowered, and the load when the transport pad 21 is pressed against the transport object 11 each time (the load at the position where the transport pad 21 changes from lowering to raising) is acquired and recorded by the load sensor 30. The load at which the transport pad 21 was able to hold and transport the setting workpiece without any problems is set as the target load.

[0035] For example, the amount of descent of the transport pad 21 is gradually increased, and the load at the descent position where the transport pad 21 can first securely lift and transport the object to be transported by suction is the minimum required load. This minimum required load, or a load with a small margin above the minimum required load, can be set as the target load.

[0036] Alternatively, the setting workpiece may be made of the same material as the object to be transported 11, and in the setting step, the transport pad 21 may be lowered until the setting workpiece is damaged, and the load sensor 30 may detect the boundary load (maximum limit load) at which the pressing force of the transport pad 21 becomes excessive. By setting the target load to be smaller than the maximum limit load, the target load can be set with even greater precision, and it is possible to reliably prevent the pressing force of the transport pad 21 from becoming excessive. In other words, in addition to the minimum required load, which is the lower limit, the maximum limit load, which is the upper limit at which the object to be transported 11 is not damaged, may be determined, and the target load may be set with a range between the minimum required load and the maximum limit load.

[0037] As described above, in the setting step, a target load is set that provides sufficient pressure for the transport pad 21 to suction and hold the object to be transported 11. Then, the target load is stored in the memory of the control unit 31.

[0038] Furthermore, when transporting multiple objects 11 in succession, it is possible to perform the setting step by holding the first object 11 on the holding table 10 instead of using a setting workpiece. However, during the setting step, there is a possibility that a strong pressing force from the transport pads 21 may act on the objects 11, or that the pressing force from the transport pads 21 may be insufficient and the objects 11 may fall during transport. Therefore, from the viewpoint of preventing damage to the objects 11, it is desirable to use a setting workpiece in the setting step.

[0039] Based on the target load set in the setup step, the actual transport object 11 is transported. With the transport object 11 held on the holding surface 16 of the holding table 10, the motor 242 of the lifting mechanism 24 is operated to lower the transport pad 21. When the suction pad 25 contacts the upper surface 112 of the transport object 11, the load value detected by the load sensor 30 increases in accordance with the lowering of the transport pad 21. The control unit 31 compares the load detected by the load sensor 30 with the target load stored in memory and causes the lifting mechanism 24 to lower the transport pad 21 until the detected load reaches the target load. Then, when the detected load reaches the target load, the motor 242 of the lifting mechanism 24 is stopped, and the lowering of the transport pad 21 is stopped. At this stage, a pressing force is applied so that the transport pad 21 can reliably hold the upper surface 112 of the transport object 11 by suction, so the suction source 27 is operated to apply suction force to the suction pad 25, and the transport object 11 is held without falling off the transport pad 21. Furthermore, since the target load is set so that the pressing force by the transport pad 21 is not excessive, there is no risk of the transport object 11 being damaged when the transport pad 21 holds the transport object 11.

[0040] Next, the motor 242 of the lifting mechanism 24 is activated to raise the transport pad 21, which is holding the object to be transported 11, and the object to be transported 11 is removed from the holding surface 16 of the holding table 10. Once the object to be transported 11 is separated from the holding surface 16, the motor 235 of the horizontal movement mechanism 23 is activated to move the transport pad 21 horizontally and transport the object to be transported 11 to a position away from above the holding table 10.

[0041] In the first form of the above transport method, since the appropriate target load for a transport object 11 of specific specifications is constant, once the target load is set, even if conditions such as the height of the holding surface 16 are changed afterward, the pressing action of the transport pad 21 against the transport object 11 can be controlled based on reaching the target load, without being affected by the change.

[0042] A second embodiment of the conveying method of this disclosure will now be described. The setting step is the same as the first embodiment described above, up to the point of setting an appropriate target load. As shown in Figure 1, the conveying mechanism 20 is equipped with a height gauge 32 on a horizontal moving table 233, which has a scale indicating the vertical position change of the conveying pad 21 and the conveying arm 22. The conveying arm 22 is equipped with an indicator part 33 that points to the scale on the height gauge 32. The horizontal moving table 233 on which the height gauge 32 is formed is configured so that its height position in the vertical direction does not change relative to the holding table 10. Therefore, by reading the height position of the indicator part 33 relative to the scale on the height gauge 32 when the target load is set, the relative target height (target position) of the conveying pad 21 with respect to the holding table 10 when the target load is reached can be recorded.

[0043] Based on the target height determined in this way, the amount of descent of the transport pad 21 is set, and when the object to be transported 11 held on the holding table 10 is unloaded, the motor 242 of the lifting mechanism 24 is operated to lower the transport pad 21 to the target height. As an example of operation control for lowering the transport pad 21 to the target height, the transport mechanism 20 is equipped with an imaging unit (camera) capable of continuously capturing images of the height gauge 32, and the control unit 31 monitors the images (video) captured by the imaging unit and uses image recognition processing to determine whether the scale position on the height gauge 32 indicated by the indicator unit 33 has reached the position corresponding to the target height. When it is detected that the target height has been reached, the motor 242 of the lifting mechanism 24 is stopped and the descent of the transport pad 21 is stopped.

[0044] The method for detecting the height position of the transport pad 21 and the transport arm 22 is not limited to this. For example, the height position may be detected using an ultrasonic sensor that emits ultrasonic waves toward the transport pad 21 and the transport arm 22 and measures the distance to the transport pad 21 and the transport arm 22 based on the time it takes to detect the reflected ultrasonic waves, or a magnetic sensor that detects changes in the magnetic field when the transport pad 21 and the transport arm 22 move. Alternatively, the height position may be detected using an optical distance measuring sensor that irradiates the transport pad 21 and the transport arm 22 with light such as laser light and measures the distance to the transport pad 21 and the transport arm 22 based on the time it takes to detect the reflected light.

[0045] The control described above stops the descent of the transport pad 21 at the target load, and a pressing force is applied that allows the transport pad 21 to reliably hold the upper surface 112 of the object to be transported 11 by suction. By operating the suction source 27 and applying suction force to the suction pad 25, the object to be transported 11 is held without falling off the transport pad 21. Furthermore, the target load is set so that the pressing force applied by the transport pad 21 is not excessive, so there is no risk of the object to be transported 11 being damaged when the transport pad 21 holds it.

[0046] Next, the motor 242 of the lifting mechanism 24 is activated to raise the transport pad 21, which is holding the object to be transported 11, and the object to be transported 11 is unloaded from the holding table 10. Furthermore, the motor 235 of the horizontal movement mechanism 23 is activated to move the transport pad 21 horizontally, transporting the object to be transported 11 to a position away from above the holding table 10.

[0047] Furthermore, if the height of the holding surface 16 changes due to the self-grinding of the holding table 10, the appropriate target height will also change. Therefore, it is desirable to record the target height corresponding to the target load again when conditions such as the height of the holding surface 16 change.

[0048] In the configuration shown in Figure 1, the load sensor 30 is provided on the transport pad 21 side that transports the object to be transported 11. However, as shown in the configuration in Figure 3, the load sensor 40 may be provided on the holding table 10 side that holds the object to be transported 11. The load sensor 40 is provided between the lower surface of the frame 12 and the upper surface of the base 17 that constitute the holding table 10. Similar to the load sensor 30 described above, the load sensor 40 is composed of a piezoelectric sensor or a strain gauge sensor.

[0049] Furthermore, multiple load sensors 40 are arranged at different positions in the horizontal direction (in a planar direction parallel to the lower surface 111 and upper surface 112 of the object to be conveyed 11). For example, as shown in Figure 2, when the holding table 10 is approximately circular in plan view, three load sensors 40 are arranged at approximately equal intervals (120° intervals) around the circumferential direction of the holding table 10, similar to the arrangement of the load sensors 30 described above.

[0050] When the holding table 10 is equipped with a load sensor 40, the transport pad 21 does not need to be equipped with a load sensor. In the configuration shown in Figure 3, the suction pad 25 is positioned on the lower surface of the main body 29 of the transport pad 21 without the interposition of a load sensor.

[0051] In the configuration shown in Figure 3, when the lifting mechanism 24 lowers the transport pad 21 and the suction pad 25 is pressed against the object to be transported 11, the pressing force is transmitted from the object to be transported 11 to the holding surface 16 of the holding table 10, and the holding table 10 receives a downward pressing force. At this time, the load applied to the holding table 10 is detected by the load sensor 40. The detection signal from the load sensor 40 is transmitted to the control unit 31, which controls the operation of the transport mechanism 20.

[0052] The load change when the transport pad 21 is lowered and the suction pad 25 is pressed against the object to be transported 11 is detected by the load sensor 40. Therefore, in the same manner as the above configuration in which the load sensor 30 is provided on the transport pad 21 side, it is possible to perform a setting step using load detection by the load sensor 40 and set an optimal target load that is neither too much nor too little for the transport pad 21 to hold the object to be transported 11. In the setting step, it is desirable to hold a setting workpiece with the same thickness as the object to be transported 11 on the holding table 10. Then, when the transport pad 21 holds the object to be transported 11, by applying the first form described above in which the control unit 31 determines when the target load has been reached, or the second form described above in which the control unit 31 determines when the target height corresponding to the target load has been reached, the transport pad 21 can be automatically pressed against the object to be transported 11 with the optimal load, and the object to be transported 11 can be reliably held by the transport pad 21 without damaging the object to be transported 11.

[0053] As described above, the transport method of this disclosure allows the transport pad 21 to be pressed against the object to be transported 11 held on the holding table 10 with an optimal pressing force that is neither too strong nor too weak, thereby preventing damage to the object to be transported 11 and ensuring that the object to be transported 11 is securely held and transported by the transport pad 21. After setting a target load using load sensors 30 and 40 provided on the transport pad 21 or the holding table 10, in either the first form (where the control unit 31 determines when the target load is reached) or the second form (where the control unit 31 determines when the target height corresponding to the target load is reached), the transport pad 21 is pressed against the object to be transported 11 with an automatically optimized pressing force controlled by the control unit 31. This eliminates the need for the operator to manage or adjust the pressing force, resulting in excellent time efficiency and eliminating the risk of human error in setting.

[0054] In particular, in the transport method of this disclosure, load sensors 30 and 40 capable of detecting minute changes in load are provided on the transport pad 21 that is pressed against the object to be transported 11, or on the holding table 10 that holds the object to be transported 11. This makes it possible to determine the state of pressure applied from the transport pad 21 to the object to be transported 11 with higher accuracy than indirectly detecting changes in load via the torque of the motor 242 of the lifting mechanism 24.

[0055] Since multiple load sensors 30 and 40 are provided at different positions in a planar direction parallel to the lower surface 111 or upper surface 112 of the object to be transported 11, by comparing the load values ​​detected by these multiple load sensors 30 and 40, information such as the posture of the transport pad 21 and the shape of the object to be transported 11 can be obtained, enabling even more accurate transport control.

[0056] For example, if the transport pad 21 is tilted relative to the holding surface 16 of the holding table 10, when the transport pad 21 is lowered and pressed against the object to be transported 11, the multiple suction pads 25 will not contact the object to be transported 11 at the same time, but will contact it with a time difference. This will result in differences in the timing of load increase detection by the multiple load sensors 30 and 40. The control unit 31 monitors the timing and speed of load increase detected by each load sensor 30 and 40, and if there is a variation greater than a predetermined amount in the timing and speed of the load increase relative to each other, it is possible to determine that the transport pad 21 is tilted relative to its normal orientation. If the tilt of the transport pad 21 relative to the object to be transported 11 is large, even if the transport pad 21 is pressed against the upper surface 112 of the object to be transported 11, the suction force exerted by the individual suction pads 25 will be uneven, and there is a risk that the object to be transported 11 cannot be held stably. Alternatively, excessive pressure may be applied to the object being transported 11 to correct the tilt of the transport pad 21, potentially damaging the object 11. By arranging multiple load sensors 30 and 40 in the planar direction, such tilting of the transport pad 21 can be detected, preventing transport failures in the transport mechanism 20.

[0057] Furthermore, if the object to be transported 11 is partially curved relative to the holding surface 16 of the holding table 10 (a shape that is lifted away from the holding surface 16), when the transport pad 21 is brought close to the object to be transported 11, there is a possibility that multiple suction pads 25 will come into contact with the object to be transported 11 at different but simultaneous timings. If the curvature of the object to be transported 11 is small, the pressure from the transport pad 21 can eliminate the curvature and make the object to be transported 11 conform to the holding surface 16. However, if the curvature of the object to be transported 11 is large, the amount of deformation of the object to be transported 11 when the transport pad 21 is pressed hard may exceed the allowable strength range, potentially damaging the object to be transported 11. The control unit 31 monitors the timing and speed of load increase detected by the individual load sensors 30 and 40, and even if the transport pad 21 is adjusted to prevent tilting, if there is a variation in the timing and speed of the load increase that exceeds a predetermined level, it may be determined that there is a partial shape defect in the object to be transported 11.

[0058] In this way, by arranging multiple load sensors 30 and 40 in the planar direction, it is possible not only to detect with high accuracy the optimal pressing force of the transport pad 21 against the object to be transported 11, but also to identify situations where abnormalities are occurring, such as tilting of the transport pad 21 or excessive warping of the object to be transported 11. In these situations, there is a high possibility that the object to be transported 11 may be damaged due to pressing the transport pad 21 too hard in certain areas, or that the pressing force of the transport pad 21 may be insufficient in certain areas, resulting in poor holding. Since it may not be possible to set the optimal pressing force, providing multiple load sensors 30 and 40 can prevent transport failures in the transport mechanism 20.

[0059] In the configuration shown in Figure 2, three load sensors 30 and 40 are arranged at equal intervals in the circumferential direction on the circular transport pad 21 and holding table 10 in a plan view. This arrangement ensures that the distance of each load sensor 30 and 40 from the center of the transport pad 21 and holding table 10 is equal, and the detection conditions for each load sensor 30 and 40 are standardized, making it easier to obtain accurate information such as the tilt of the transport pad 21 and the curvature of the transported object 11. Furthermore, by providing three or more load sensors 30 and 40, the accuracy of detecting the tendency of load bias in the planar direction is improved.

[0060] The embodiments described above are preferred examples of the conveying method of this disclosure and are not limited to these embodiments. For example, Figures 1 and 3 show a structure in which an object to be conveyed 11 is held on a holding table 10 with a holding surface 16 facing upward, and a conveying pad 21 descends and approaches to press against the object to be conveyed 11. However, the application of the conveying method of this disclosure is not limited to such holding structures. For example, the holding part corresponding to the holding table 10 may have a holding surface perpendicular to the horizontal direction, and the conveying part corresponding to the conveying pad 21 may move horizontally to press against the object to be conveyed. In this case, the force with which the conveying part presses against the object to be conveyed acts horizontally, so a load sensor provided on the conveying part or holding part detects a load acting horizontally on the conveying part or holding part. Furthermore, when performing the control of the second embodiment described above, the relative target position of the conveying part with respect to the holding part when the target load is reached is not a target height indicating a position in the vertical direction, but a target position in the horizontal direction.

[0061] The holding portion is not limited to the holding table 10 described above, which holds the entire surface of one side of the object to be transported 11. For example, the holding portion may be composed of a pair of parallel holding rails, and the transport portion may be pressed against the object to be transported, which is held across the pair of holding rails, to transfer the holding. In this case, the transport portion and the holding portion do not have to be opposite each other in the thickness direction of the object to be transported. For example, the holding portion (holding rails) may hold the area near the edge of the object to be transported, and the transport portion may be pressed against the area of ​​the object closer to the center than the edge.

[0062] Alternatively, the holding unit may be another transport unit that transports the object to be transported. For example, a transport pad with a structure such that the transport pad 21 in the transport mechanism 20 is inverted may constitute the holding unit. In this case, the first transport unit that first holds the object to be transported corresponds to the holding unit, and the second transport unit that then receives the object to be transported corresponds to the transport unit.

[0063] In the above embodiment, the holding surface 16 of the holding table 10 and the transport pad 21 are shown to be circular, but the shape of the holding part and the transport part are not limited to circular. For example, if the object to be transported is a rectangular package substrate, the holding part and the transport part may be equipped with a rectangular holding table and a rectangular transport pad, respectively. In particular, according to the transport method of this disclosure, as long as the warping of the object to be transported is not excessive, it is possible to set an optimal target load and automatically set the pressing force during transport even for objects that have some warping, making it suitable for transporting package substrates that are relatively prone to warping.

[0064] The arrangement of the load sensors may differ from that of the above embodiment depending on the shape of the transport and holding sections. For example, if the transport and holding sections are rectangular, a total of four load sensors may be placed near the four corners.

[0065] In the above embodiment, this method is applied to a transport mechanism 20 that transports the object to be transported 11 linearly by a horizontal movement mechanism 23. However, the form in which the object to be transported is transported is not limited to this embodiment. For example, it can also be applied to a transport mechanism that moves the transport unit by a rotational movement around a rotation axis.

[0066] Furthermore, this method is not limited to transport mechanisms that move only along a fixed path along the guide rail 232, as in the horizontal movement mechanism 23 described above, but can also be applied to transport systems that transport objects using a transport vehicle capable of traveling along any transport path. Specifically, a transport unit that can be extended and retracted from the transport vehicle is provided, the transport unit is extended from the transport vehicle and pressed against the object to be transported on the holding unit to hold it by suction, and the transport unit holding the object is retracted into the transport vehicle and the transport vehicle is driven. The transport method of this disclosure is also useful in the transfer of objects from the holding unit to the transport unit in such a transport system.

[0067] Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability]

[0068] According to the conveying method of the present invention, the conveying unit can hold and convey the object with high precision, reducing the effort required for setting up and managing conveying, and improving conveying efficiency. [Explanation of symbols]

[0069] 10: Holding table (holding part) 11: Object to be transported 12:Frame body 13: Porous board 14: Flow channel 15: Suction source 16: Holding surface 17: Pedestal 20: Conveying mechanism 21: Conveyor pad (conveyor section) 22: Transport arm (transport section) 23: Horizontal movement mechanism 24: Lifting mechanism 25: Suction pad 26: Flow path 27: Suction source 28: Intermediate support member 29: Main body 30: Load sensor 31: Control Unit 32: Height gauge 33: Index section 40: Load sensor 111: Bottom surface (one side of the object being transported) 112: Top surface (the other side of the object being transported) 231: Column 232: Guide rail 233: Horizontal moving table 234: Ball screw 235: Motor 241: Ball screw 242: Motor 243: Guide rail 244: Encoder

Claims

1. A conveying method in which one side of an object to be conveyed is held by a holding unit, and the other side of the object to be conveyed is held by a conveying unit, and the object to be conveyed is conveyed, The system includes a sensor that detects the load applied to at least one of the holding section and the transport section, A target load is set for when the object to be transported, which is held in the holding section, is held in the transport section. The transport unit is pressed relative to the object to be transported, which is held in the holding unit, until the load detected by the sensor reaches the target load, thereby holding the object to be transported in the transport unit, and the transport unit then performs the operation of unloading the object from the holding unit. Transportation method.

2. A conveying method in which one side of an object to be conveyed is held by a holding unit, and the other side of the object to be conveyed is held by a conveying unit, and the object to be conveyed is conveyed, The system includes a sensor that detects the load applied to at least one of the holding section and the transport section, A target load is set for when the object to be transported, which is held in the holding section, is held in the transport section. The relative target position of the conveying section with respect to the holding section when the target load is reached is recorded. The transport unit holds the object to be transported based on the target position, and the transport unit performs the operation of unloading the object from the holding unit. Transportation method.

3. The conveying method according to claim 1 or 2, characterized in that a plurality of sensors are provided in a planar direction along one or the other surface of the object to be conveyed.

4. The conveying method according to claim 1 or 2, characterized in that when setting the target load, the holding unit holds a setting workpiece whose contact area with the conveying unit is the same as that of the object to be conveyed, and the conveying unit detects a load that allows the setting workpiece to be held.

5. The conveying method according to claim 1 or 2, characterized in that the conveying unit holds the object to be conveyed by suction.

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