Method for conveying plate-like object

Abstract

To provide a method for conveying a plate-like object, which can reduce the probability that a robot hand cannot hold a warped plate-like object in an unloaded state, or that the plate-like object falls from the robot hand during transportation and is damaged.SOLUTION: A method for conveying a warped plate-like object in an unloaded state includes an upper holding step of causing a robot hand to hold a plate-like object and a warp mitigation plate by applying suction force from the robot hand through a through hole to the plate-like object on which the warp mitigation plate, with a through hole formed therein, is placed, and a conveying step of, after the upper holding step, moving the robot hand holding the plate-like object and the warp mitigation plate to convey the plate-like object and the warp mitigation plate.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for transporting a warped plate-like object in an unloaded state. [Background technology]

[0002] Chips of devices such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by thinning a plate-like object such as a wafer having a plurality of devices formed on its front surface, and then dividing the plate-like object along the boundaries of the plurality of devices.

[0003] The thinning of the plate-like object is performed, for example, by grinding the back side thereof (see, for example, Patent Document 1). The thinned plate-like object is divided, for example, by forming modified parts along the boundaries of multiple devices on the front side of the plate-like object using a laser beam with a wavelength that transmits the material, and then applying an external force to the plate-like object (for example, grinding the back side thereof) so that the plate-like object is divided starting from the modified parts (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-92776 [Patent Document 2] JP 2013-171846 A Summary of the Invention [Problem to be solved by the invention]

[0005] The transportation of the plate-like object before and after various processes such as forming a plurality of devices on the front side of the plate-like object, grinding the back side of the plate-like object, or forming a modified portion on the front side of the plate-like object is often performed by moving a robot hand that holds the plate-like object. Note that the robot hand generally holds the plate-like object by applying a suction force to the plate-like object.

[0006] However, when various processes are performed on a plate-like object, the plate-like object may warp when no external force is applied (unloaded state). In this case, a gap may be generated between the plate-like object and the robot hand, weakening the suction force acting on the plate-like object from the robot hand. In this case, the robot hand may not be able to hold the plate-like object, or the plate-like object may fall from the robot hand during transportation and be damaged.

[0007] In view of this, the object of the present invention is to provide a method for transporting plate-like objects that can reduce the likelihood that a robot hand will be unable to hold a warped plate-like object in an unloaded state, or that the plate-like object will fall from the robot hand and be damaged while being transported. [Means for solving the problem]

[0008] According to the present invention, there is provided a method for transporting a warped plate-like object in an unloaded state, the method comprising: an upper holding step in which a robot hand holds the plate-like object and the warp mitigation plate by applying suction force from the robot hand through a through hole to the plate-like object on which the warp mitigation plate having a through hole formed therein; and a transport step in which, after the upper holding step, the robot hand holding the plate-like object and the warp mitigation plate is moved to transport the plate-like object and the warp mitigation plate.

[0009] The method for transporting a plate-like object of the present invention preferably further comprises a placing step of placing the warp reducing plate on the plate-like object while the chuck table holds the plate-like object by applying a suction force from the chuck table on which the plate-like object is placed, and a releasing step of releasing the plate-like object by the chuck table by eliminating the suction force acting on the plate-like object from the chuck table after the placing step and before the upper holding step. In addition, the method for transporting a plate-like object of the present invention preferably further comprises a carrying step of carrying an unprocessed plate-like object having a warp smaller than that of the plate-like object in an unloaded state into the chuck table, a lower holding step of holding the unprocessed plate-like object by applying a suction force from the chuck table to the unprocessed plate-like object after the carrying step, and a processing step of processing the unprocessed plate-like object so as to form the plate-like object while the chuck table holds the unprocessed plate-like object after the lower holding step and before the placing step.

[0010] Alternatively, it is preferable that the method for transporting a plate-like object of the present invention further comprises, after the transport step performed to transport the plate-like object and the warp reduction plate to a chuck table, a releasing step in which the robot hand releases the plate-like object and the warp reduction plate by eliminating the suction force acting on the plate-like object from the robot hand through the through hole, after the releasing step, a lower holding step in which the chuck table holds the plate-like object by applying a suction force from the chuck table to the plate-like object, after the lower holding step, a separation step in which the warp reduction plate is separated from the plate-like object while the chuck table is holding the plate-like object, and after the separation step, a processing step in which the plate-like object is processed while the chuck table is holding the plate-like object.

[0011] Preferably, the warp mitigating plate is partitioned into a first region in which the through holes are formed and a second region in which the through holes are not formed, the conveyance of the warp mitigating plate for placing it on the plate-like object and for separating it from the plate-like object is performed with suction force applied to the second region without applying suction force to the first region, and the conveyance of the warp mitigating plate for moving it together with the plate-like object is performed with suction force applied to the first region. Alternatively, the warp mitigating plate includes a region made of a porous body including the through holes, and the conveyance of the warp mitigating plate for moving it together with the plate-like object is performed with suction force applied to the region. Effect of the Invention

[0012] In the present invention, a suction force is applied from a robot hand through the through holes to a plate-like object on which a warpage mitigating plate having through holes is placed. In this case, the suction force can be applied from the robot hand to the plate-like object in a state in which the warpage of the plate-like object is mitigated by gravity acting on the warpage mitigating plate.

[0013] Therefore, in this method, the suction force acting on the plate-like object from the robot hand is prevented from decreasing, and as a result, it is possible to reduce the probability that the robot hand cannot hold the plate-like object, or that the plate-like object falls from the robot hand during transportation and is damaged. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1(A) is a plan view that shows a schematic example of a plate-like object warped in an unloaded state, and FIG. 1(B) is a cross-sectional view that shows a schematic example of the plate-like object shown in FIG. 1(A). [Diagram 2] FIG. 2(A) is a plan view showing a schematic example of a warp mitigation plate used when transporting a plate-like object, and FIG. 2(B) is a cross-sectional view showing a schematic example of the warp mitigation plate shown in FIG. 2(A). [Diagram 3]FIG. 3(A) is a perspective view showing a schematic diagram of a transport unit for transporting a plate-like object together with a warp mitigation plate, and FIG. 3(B) is a cross-sectional view showing a schematic diagram of a robot hand included in the transport unit shown in FIG. 3(A). [Figure 4] FIG. 4 is a flow chart showing an example of a method for transporting a plate-shaped object together with a warp reducing plate by using a transport unit. [Diagram 5] 5(A) and 5(B) are cross-sectional views each showing a schematic view of the holding step shown in FIG. [Figure 6] FIG. 6 is a flow chart showing an example of a method for transporting a plate-like object, in which a warp-reducing plate is placed on the plate-like object in a state where the warp of the plate-like object has been reduced, and then the plate-like object is transported together with the warp-reducing plate. [Figure 7] 7(A) is a cross-sectional view that typically illustrates the placement step shown in FIG. 6, and FIG. 7(B) is a cross-sectional view that typically illustrates the release step shown in FIG. [Figure 8] FIG. 8 is a flowchart showing an example of a method for transporting a plate-like object, in which an unprocessed plate-like object is processed in a laser processing apparatus equipped with a chuck table shown in FIG. 7(A) and FIG. 7(B) so as to form a modified portion, and then the plate-like object is transported together with a warp mitigation plate. [Figure 9] 9(A) is a cross-sectional view that typically shows the state of the loading step shown in FIG. 8, and FIG. 9(B) is a cross-sectional view that typically shows the state of the lower holding step shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing a schematic view of the processing step shown in FIG. [Figure 11] FIG. 11 is a flow chart showing an example of a method for transporting a plate-shaped object, in which the plate-shaped object is transported together with a warp reducing plate before being processed. [Figure 12] 12A is a cross-sectional view that typically illustrates the state of the transport step shown in FIG. 11, and FIG. 12B is a cross-sectional view that typically illustrates the state of the release step shown in FIG. [Figure 13]13A is a cross-sectional view that typically illustrates the state of the lower holding step shown in FIG. 11, and FIG. 13B is a cross-sectional view that typically illustrates the state of the separation step shown in FIG. [Figure 14] 14A to 14C are cross-sectional views each showing a schematic diagram of the processing step shown in FIG. [Figure 15] FIG. 15(A) is a plan view showing a schematic diagram of another example of a plate-shaped object warped in an unloaded state, and FIG. 15(B) is a cross-sectional view showing a schematic diagram of yet another example of a plate-shaped object warped in an unloaded state. [Figure 16] FIG. 16(A) is a plan view showing a schematic diagram of another example of a warp mitigation plate used when transporting a plate-like object, and FIG. 16(B) is a plan view showing a schematic diagram of yet another example of a warp mitigation plate used when transporting a plate-like object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1(A) is a plan view showing an example of a plate-like object warped in an unloaded state, and Fig. 1(B) is a cross-sectional view showing the plate-like object shown in Fig. 1(A). The plate-like object 11 shown in Fig. 1(A) and Fig. 1(B) is, for example, a wafer made of silicon (Si) and having a chamfered outer edge.

[0016] A plurality of devices 13 are provided in a matrix arrangement on the front surface 11a side of the plate-like object 11. Each of the plurality of devices 13 includes an element for constituting, for example, an IC, a semiconductor memory, or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0017] Furthermore, modified parts 15 extending in a lattice pattern along the boundaries of the multiple devices 13 are formed on the front surface 11a side of the plate-like object 11. These modified parts 15 are parts where the crystal structure of the material of the plate-like object 11 is disrupted, and are formed, for example, by positioning the focal point of a laser beam with a wavelength that transmits through this material inside the plate-like object 11 and moving this focal point and the plate-like object 11 relatively.

[0018] When the modified portion 15 is formed on the front surface 11a side of the plate-like object 11, internal stress is generated on the front surface 11a side and the volume of the front surface 11a side expands. Therefore, in an unloaded state, the front surface 11a side of the plate-like object 11 protrudes and the back surface 11c side of the plate-like object 11 warps so as to be recessed.

[0019] There is no limitation on the material or shape of the plate-like object 11. The plate-like object 11 may be made of, for example, a semiconductor other than silicon (e.g., silicon carbide (SiC) or gallium nitride (GaN)) or an insulator (e.g., sapphire (Al 2 O 3 ) or quartz glass (SiO 2 In addition, the plate-like object 11 may be warped so that its front surface 11a side is recessed and its back surface 11c side is protruding when no load is applied.

[0020] Fig. 2(A) is a plan view showing a schematic example of a warp mitigating plate used when transporting a plate-like object 11, and Fig. 2(B) is a cross-sectional view showing a schematic example of the warp mitigating plate shown in Fig. 2(A). The warp mitigating plate 17 shown in Fig. 2(A) and Fig. 2(B) is a circular plate made of ceramics and / or metal and has a chamfered outer edge.

[0021] The warp mitigating plate 17 is divided into an annular first region 17a in a plan view and a circular second region 17b surrounded by the first region 17a. Note that, in Fig. 2(A), the boundary between the first region 17a and the second region 17b is shown by a dashed line, but this is for convenience and does not exist in the actual warp mitigating plate 17.

[0022] Further, a plurality of through holes 19 are formed in the first region 17a, whereas no through holes 19 are formed in the second region 17b. The warp mitigation plate 17 has a mass that is 1 to 10 times, preferably 2 to 8 times, and more preferably 3 to 6 times that of the plate-like object 11. The diameter of the plate-like object 11 (i.e., the outer diameter of the first region 17a) is, for example, approximately equal to the diameter of the plate-like object 11.

[0023] There is no limitation on the material or shape of the warp mitigating plate 17. The warp mitigating plate 17 may be, for example, a circular plate having a diameter different from that of the plate-like object 11. Alternatively, the planar shape of the warp mitigating plate 17 may be non-circular (for example, rectangular or elliptical). Moreover, the outer edge of the warp mitigating plate 17 does not have to be chamfered.

[0024] Fig. 3(A) is a perspective view showing a schematic diagram of a transport unit for transporting a plate-like object 11 together with a warp reducing plate 17. The transport unit 2 shown in Fig. 3(A) has a cylindrical first drive unit 4 extending along the vertical direction. The lower end of this first drive unit 4 is connected to a horizontal movement mechanism (not shown) having, for example, a ball screw and a motor. When this horizontal movement mechanism is operated, the first drive unit 4 moves along the horizontal direction.

[0025] An actuator (not shown) rotatable around a vertical axis is provided inside first driving unit 4, and this actuator has a piston rod that is movable vertically. The piston rod is exposed through an opening formed in the top surface of first driving unit 4, and a robot arm 6 is connected to the upper end of the piston rod.

[0026] Therefore, the robot arm 6 is movable in the horizontal and vertical directions. That is, when a horizontal movement mechanism connected to the first driving unit 4 is operated, the robot arm 6 moves in the horizontal direction together with the first driving unit 4. Also, when an actuator provided inside the first driving unit 4 is operated, the robot arm 6 moves (rises and falls) in the vertical direction.

[0027] The robot arm 6 has a plurality of joints. Specifically, the robot arm 6 has a plate-shaped first arm portion 6a extending perpendicular to the vertical direction. The lower side of one end of the first arm portion 6a is connected to the upper end of a piston rod. In addition, the lower side of a cylindrical first joint portion (not shown) is connected to the upper side of the other end of the first arm portion 6a.

[0028] A plate-shaped second arm 6b extending perpendicular to the vertical direction is connected to the upper side of the first joint. The lower side of one end of this second arm 6b is connected to the upper side of the other end of the first arm 6a via the first joint in a manner that allows it to rotate around a rotation axis along the vertical direction. The lower side of a cylindrical second joint 6c is connected to the upper side of the other end of the second arm 6b.

[0029] A rectangular parallelepiped second drive unit 6d extending perpendicular to the vertical direction is connected to the upper side of the second joint 6c. A lower side of one end of the second drive unit 6d is connected to the upper side of the other end of the second arm 6b via the second joint 6c in a manner that allows the second drive unit 6d to rotate around a rotation axis along the vertical direction.

[0030] In addition, a motor (not shown) is provided inside the second driving unit 6d to rotate a rotatable spindle 6e around a rotation axis along a direction perpendicular to the vertical direction. The spindle 6e is exposed through an opening formed in one surface of the second driving unit 6d, and the robot hand 8 is connected to the tip of the spindle 6e via a plate-shaped connecting part 6f.

[0031] Therefore, the robot hand 8 can rotate together with the spindle 6e around a rotation axis along a direction perpendicular to the vertical direction. Fig. 3(B) is a cross-sectional view showing the robot hand 8. Fig. 3(B) also shows schematic components that can communicate with the robot hand 8.

[0032] The robot hand 8 has a disk-shaped main body 10 and a rectangular parallelepiped wrist 12 provided between the main body 10 and a connecting portion 6f of the robot arm 6 so as to connect the two. The main body 10 has a frame 10a composed of a disk portion and a cylindrical portion provided on the outer circumferential region of the disk portion. The cylindrical portion of the frame 10a has an inner diameter slightly smaller than the diameter of the warp mitigation plate 17 and an outer diameter slightly larger than the diameter of the warp mitigation plate 17, for example.

[0033] A disk-shaped porous body 10b made of ceramics or the like and having a diameter roughly equal to the inner diameter of the cylindrical part is fixed in the recess defined by the disk part and the cylindrical part of the frame body 10a. The porous body 10b includes a number of through holes extending in the thickness direction. One surface of the main body 10 (the surface of the cylindrical part of the frame body 10a and the surface of the porous body 10b) is roughly horizontal.

[0034] Furthermore, a flow path 14 is formed in the disk portion of the frame body 10a, opening at the bottom surface of the recess, and this flow path 14 is connected to a suction source 18 via a valve 16a, and is also connected to a gas supply source 20 via a valve 16b. The suction source 18 includes, for example, an ejector. The gas supply source 20 includes, for example, a tank for storing a gas (for example, air) in a high pressure state, a filter for removing foreign matter mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0035] 4 is a flow chart showing an example of a method for transporting a plate-like object 11 together with a warp reducing plate 17 by using the transport unit 2. In this method, first, the robot hand 8 holds the plate-like object 11 and the warp reducing plate 17 (upper holding step S1).

[0036] 5(A) and 5(B) are cross-sectional views each showing a schematic view of the upper holding step S1. In this upper holding step S1, first, the robot hand 8 is moved so that the porous body 10b included in the main body 10 of the robot hand 8 contacts the upper surface of the warpage reducing plate 17 placed on the plate-like object 11 with the back surface 11c facing upward (see FIG. 5(A)).

[0037] At this time, the warp of the plate-like object 11 is mitigated by gravity acting on the warp mitigation plate 17, and, for example, the front surface 11a and the back surface 11c are generally flat. If the front surface 11a and the back surface 11c of the plate-like object 11 are not generally flat, the robot hand 8 may be positioned at a position where the robot hand 8 presses the plate-like object 11 and the warp mitigation plate 17 to flatten them.

[0038] Next, the valve 16a is opened and the suction source 18 is operated (see FIG. 5(B)). This causes a suction force to act on the multiple through holes 19 from the robot hand 8 (specifically, the multiple through holes contained in the porous body 10b of the main body 10). As a result, the plate-like object 11 and the warpage mitigation plate 17 are held by the robot hand 8.

[0039] After the upper holding step S1, the plate-like object 11 and the warp mitigating plate 17 are transported (transport step S2). Specifically, in this transport step S2, the plate-like object 11 and the warp mitigating plate 17 are transported by moving the robot hand 8 that holds the plate-like object 11 and the warp mitigating plate 17.

[0040] This transport step S2 is performed, for example, to carry the plate-like object 11 and the warp mitigating plate 17 into a cassette (not shown) capable of accommodating a plurality of plate-like objects 11. Specifically, this carrying is performed by moving the robot hand 8 so as to position the plate-like object 11 and the warp mitigating plate 17 at desired positions in the cassette, and then the robot hand 8 releases the plate-like object 11 and the warp mitigating plate 17.

[0041] This release is achieved by eliminating the suction force acting from the robot hand 8 on the plate-like object 11 and the warp reduction plate 17; specifically, by closing the valve 16a and stopping the operation of the suction source 18, and then opening the valve 16b and operating the gas supply source 20.

[0042] 4, a suction force is applied from a robot hand 8 to the plate-like object 11 on which a warpage mitigating plate 17 having a plurality of through holes 19 formed therein is placed, via the plurality of through holes 19. In this case, the suction force can be applied from the robot hand 8 to the plate-like object 11 in a state in which the warpage of the plate-like object 11 is mitigated by gravity acting on the warpage mitigating plate 17.

[0043] Therefore, this method suppresses a decrease in the suction force acting from the robot hand 8 to the plate-like object 11. As a result, this method can reduce the probability that the robot hand 8 cannot hold the plate-like object 11, or that the plate-like object 11 falls from the robot hand 8 during transportation and is damaged.

[0044] 4 may be carried out after placing the warpage-reducing plate 17 on the plate-like object 11 in a state where the warpage of the plate-like object 11 has been reduced. Fig. 6 is a flow chart showing an example of the plate-like object conveying method carried out in this manner.

[0045] In this method, prior to the above-mentioned upper holding step S1, the warp mitigation plate 17 is placed on the plate-like object 11 while the chuck table is holding the plate-like object 11 (placing step S3), and then the chuck table 22 releases the plate-like object 11 (releasing step S4).

[0046] Fig. 7(A) is a cross-sectional view showing a schematic diagram of the placing step S3, and Fig. 7(B) is a cross-sectional view showing a schematic diagram of the releasing step S4. The placing step S3 and the releasing step S4 are performed, for example, by utilizing the chuck table 22 shown in Fig. 7(A) and Fig. 7(B).

[0047] The chuck table 22 has a frame 22a composed of a disk portion and a cylindrical portion provided on the outer circumferential region of the disk portion. The cylindrical portion of the frame 22a has, for example, an inner diameter slightly smaller than the diameter of the plate-like object 11 and an outer diameter slightly larger than the diameter of the plate-like object 11.

[0048] A disk-shaped porous body 22b made of ceramics or the like and having a diameter approximately equal to the inner diameter of the cylindrical portion is fixed in a recess defined by the disk portion and the cylindrical portion of the frame body 22a. The porous body 22b includes a large number of through holes extending in the thickness direction. The upper surface of the chuck table 22 (the upper surface of the cylindrical portion of the frame body 22a and the upper surface of the porous body 22b) is approximately horizontal.

[0049] Furthermore, a flow path 24 that opens at the bottom surface of the recess is formed in the disk portion of the frame body 22a, and this flow path 24 is connected to a suction source 28 via a valve 26a, and is also connected to a gas supply source 30 via a valve 26b. The suction source 28 includes, for example, an ejector. The gas supply source 30 includes, for example, a tank for storing a gas (for example, air) in a high pressure state, a filter for removing foreign matter mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0050] A central region of a protective tape 21 is attached to the surface 11a of the plate-like object 11 held by the chuck table 22, and an annular frame (not shown) is attached to the outer circumferential region of the protective tape 21 so as to surround the plate-like object 11. When the plate-like object 11 and the frame are integrated through the protective tape 21 in this manner, the plate-like object 11 can be easily handled.

[0051] The holding of the plate-like object 11 by the chuck table 22 in the placing step S3 is performed, for example, by applying a suction force from the chuck table 22 on which the plate-like object 11 is placed via the protective tape 21 to the protective tape 21 and the plate-like object 11 (see FIG. 7(A)). Specifically, this holding is performed by opening the valve 26a and operating the suction source 28 with the plate-like object 11 placed on the chuck table 22 via the protective tape 21.

[0052] When the plate-like object 11 is held by the chuck table 22 in this manner, the warpage of the plate-like object 11 is alleviated by the suction force acting from the chuck table 22, and, for example, the front surface 11a and the back surface 11c become substantially flat. In this case, compared to a case in which the warpage of the plate-like object 11 is not alleviated, it becomes easier to place the warpage alleviation plate 17 at a desired position on the plate-like object 11, and the likelihood of the plate-like object 11 being damaged during this placement can be reduced.

[0053] In the placing step S3, the warpage mitigating plate 17 is placed on the plate-like object 11, for example, manually or by using a transport unit having a structure similar to that of the transport unit 2 except that the size of the robot hand is different. The transport unit used for this placing has, for example, a robot hand whose main body has a diameter approximately equal to the diameter of the second region 17b of the warpage mitigating plate 17.

[0054] This transport unit is capable of transporting the warp mitigating plate 17 while holding only the second region 17b of the warp mitigating plate 17. In other words, when this transport unit is used, the warp mitigating plate 17 is transported so as to place the warp mitigating plate 17 on the plate-like object 11 while applying suction force to the second region 17b of the warp mitigating plate 17 and not to the first region 17a of the warp mitigating plate 17.

[0055] In the release step S4, valve 26a is closed and suction source 28 is stopped, and then valve 26b is opened and gas supply source 30 is operated (see FIG. 7(B)). This causes the suction force acting on plate-like object 11 from chuck table 22 to disappear. As a result, plate-like object 11 is released from chuck table 22.

[0056] Furthermore, the method for conveying a plate-like object shown in Fig. 6 may be carried out after processing an unprocessed plate-like object so as to form a plate-like object 11, specifically, so as to form a modified portion 15 on the surface side of the plate-like object. Fig. 8 is a flow chart showing an example of the method for conveying a plate-like object carried out in this manner.

[0057] In this method, prior to the above-mentioned placing step S3, the unprocessed plate-like object is loaded onto the chuck table 22 (loading step S5), and the chuck table 22 holds the unprocessed plate-like object (lower holding step S6), after which the unprocessed plate-like object is processed to form the plate-like object 11 (processing step S7).

[0058] Fig. 9(A) is a cross-sectional view showing the loading step S5, Fig. 9(B) is a cross-sectional view showing the lower holding step S6, and Fig. 10 is a cross-sectional view showing the processing step S7. The loading step S5, the lower holding step S6, and the processing step S7 are performed in a laser processing device including, for example, a chuck table 22 and a laser beam irradiation unit 32 shown in Figs. 9(A), 9(B), and 10.

[0059] The laser beam irradiation unit 32 has a head 32a provided at the tip of a housing (not shown). The head 32a houses an optical system such as a condenser lens and a mirror, and the housing houses an optical system such as a mirror and / or a lens. The base end of the housing is connected to a moving mechanism. The moving mechanism includes, for example, a ball screw and a motor. When the moving mechanism is operated, the housing and the head 32a move in the horizontal and / or vertical directions.

[0060] The laser beam irradiation unit 32 also has a laser oscillator (not shown) containing, for example, Nd:YAG or the like as a laser medium. This laser oscillator has a wavelength (for example, 1064 nm) that transmits through the material (for example, silicon) of the plate-like object 11, and generates a pulsed laser beam. Then, after the output of this laser beam is adjusted by an attenuator (not shown), it is emitted directly downward from the head a via the housing and an optical system contained in the head 32a.

[0061] The unprocessed plate-like object 1 has the same structure as the plate-like object 11, except that the unprocessed plate-like object 1 does not have the modified portion 15. Therefore, the unprocessed plate-like object 1 has a smaller warp in an unloaded state than the plate-like object 11, and for example, its front surface 1a and back surface 1b are generally flat.

[0062] In the loading step S5, the unprocessed plate-like object 1 is loaded onto the chuck table 22, for example, manually or by using a transport unit capable of holding the frame by applying suction force to the frame integrated with the unprocessed plate-like object 1 via the protective tape 21 (see Figure 9(A)).

[0063] In the lower holding step S6, the valve 26a is opened and the suction source 28 is operated (see FIG. 9(B)). This causes a suction force to act on the protective tape 21 and the unprocessed plate-like object 1 from the chuck table 22. As a result, the protective tape 21 and the unprocessed plate-like object 1 are held by the chuck table 22.

[0064] In the processing step S7, the laser beam LB is emitted from the head 32a so that the focal point is positioned inside the unprocessed plate-like object 1, specifically, on the surface 1a side, and the unprocessed plate-like object 1 is irradiated with the laser beam LB so that the focal point passes through all of the boundaries of the multiple devices 13 (see FIG. 10). As a result, a plate-like object 11 including modified parts 15 is formed on the surface 11a side.

[0065] 4 may be carried out before processing the plate-like object 11. This processing may include, for example, grinding the back surface 11c side of the plate-like object 11 in order to divide the plate-like object 11 starting from the modified portion 15. FIG. 11 is a flow chart showing an example of the plate-like object transport method carried out in this manner.

[0066] In this method, first, the above-mentioned upper holding step S1 is performed, and then the plate-like object 11 and the warp mitigating plate 17 are transported to a chuck table (transport step S2'). Fig. 12(A) is a cross-sectional view showing the transport step S2'. In this transport step S2', for example, the plate-like object 11 and the warp mitigating plate 17 are transported from a cassette to a chuck table 34 of the grinding device.

[0067] The chuck table 34 has a frame 34a that is composed of a disk portion and a cylindrical portion provided on the outer circumferential region of the disk portion. The cylindrical portion of the frame 34a has, for example, an inner diameter that is slightly smaller than the diameter of the plate-like object 11 and an outer diameter that is slightly larger than the diameter of the plate-like object 11.

[0068] A disk-shaped porous body 34b made of ceramics or the like and having a diameter approximately equal to the inner diameter of the cylindrical part is fixed in a recess defined by the disk part and the cylindrical part of the frame 34a. The porous body 34b includes a large number of through holes extending in the thickness direction. The upper surface of the chuck table 34 (the upper surface of the cylindrical part of the frame 34a and the upper surface of the porous body 34b) may be approximately horizontal or may have a shape corresponding to the side surface of a cone.

[0069] Furthermore, a flow path 36 that opens at the bottom surface of the recess is formed in the disk portion of the frame body 34a, and this flow path 36 is connected to a suction source 40 via a valve 38a, and is also connected to a gas supply source 42 via a valve 37b. The suction source 40 includes, for example, an ejector. The gas supply source 42 includes, for example, a tank for storing a gas (for example, air) in a high pressure state, a filter for removing foreign matter mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0070] In addition, the chuck table 34 is connected to a rotation mechanism (not shown) having, for example, a pulley, a motor, etc. When this rotation mechanism is operated, the chuck table 34 rotates about a straight line passing through the center of the upper surface of the chuck table 34 as a rotation axis.

[0071] In addition, a protective tape 23 having a diameter approximately equal to that of the plate-like object 11 is attached to the surface 11a of the plate-like object 11 held by the chuck table 34. When the protective tape 23 is attached to the surface 11a of the plate-like object 11 in this manner, damage to the multiple devices 13 in the processing step S11 described later can be suppressed.

[0072] In the transport step S2', the robot hand 8 is moved so that the surface of the protective tape 23 comes into contact with the upper surface of the chuck table 34. As a result, the plate-like object 11 and the warp reducing plate 17 are transported to the chuck table 34 together with the protective tape 23.

[0073] After the transport step S2', the robot hand 8 releases the plate-like object 11 and the warp reducing plate 17 (releasing step S8). Fig. 12(B) is a cross-sectional view that typically shows the state of the releasing step S8.

[0074] In this releasing step S8, the valve 16a is closed and the operation of the suction source 18 is stopped, and then the valve 16b is opened and the gas supply source 20 is operated. This causes the suction force acting on the plate-like object 11 from the robot hand 8 through the through-holes 19 formed in the warp mitigating plate 17 to disappear. As a result, the plate-like object 11 and the warp mitigating plate 17 are released from the robot hand 8.

[0075] Incidentally, the robot hand 8 that has released the plate-like object 11 and the warp reducing plate 17 is moved so as to separate from the warp reducing plate 17 at a suitable timing after the releasing step S8 and before the separating step S10 described later.

[0076] After the releasing step S8, the chuck table 34 holds the plate-like object 11 (lower side holding step S9). Fig. 13(A) is a cross-sectional view that typically shows the state of the lower side holding step S9.

[0077] In this lower-side holding step S9, the valve 38a is opened and the suction source 40 is operated. This causes a suction force to act on the protective tape 23 and the plate-like object 11 from the chuck table 34. As a result, the protective tape 23 and the plate-like object 11 are held by the chuck table 34.

[0078] After the lower holding step S9, the warp reducing plate 17 is separated from the plate-like object 11 (separation step S10). Fig. 13(B) is a cross-sectional view that typically shows the state of the separation step S10.

[0079] In this separation step S10, the warpage mitigating plate 17 is separated from the plate-like object 11, for example, manually or by using a transport unit having a structure similar to that of the transport unit 2 except that the size of the robot hand is different. The transport unit used for this separation has, for example, a robot hand whose main body has a diameter approximately equal to the diameter of the second region 17b of the warpage mitigating plate 17.

[0080] This transport unit is capable of transporting the warpage mitigating plate 17 while holding only the second region 17b of the warpage mitigating plate 17. In other words, when this transport unit is used, the warpage mitigating plate 17 is transported to separate the warpage mitigating plate 17 from the plate-like object 11 while applying suction force to the second region 17b of the warpage mitigating plate 17 and not to the first region 17a of the warpage mitigating plate 17.

[0081] After the separation step S10, the plate-like object 11 is processed (processing step S11). Fig. 14 is a cross-sectional view showing the processing step S11. For example, in the processing step S11, the back surface 11c of the plate-like object 11 is ground using a grinding unit 44 provided above the chuck table 34.

[0082] The grinding unit 44 has a spindle 46 extending in the vertical direction. The lower end (tip) of the spindle 46 is a disk-shaped mount 48 whose diameter is larger than the radius of the plate-like object 11. A plurality of holes (not shown) are formed in the outer circumferential region of the mount 48, penetrating the mount 48 in the thickness direction, and a bolt (not shown) is inserted into each hole.

[0083] Furthermore, a grinding wheel 50 is attached to the underside of the mount 48 using a number of bolts. This grinding wheel 50 has an annular base 52 made of a metal material such as stainless steel or an aluminum alloy. The outer diameter of the base 52 is roughly equal to the diameter of the mount 48, and a number of grinding stones 54 are provided discretely in an annular shape on its underside.

[0084] Each of the grinding wheels 54 includes a bond material such as vitrified or resinoid, and abrasive grains such as diamond dispersed in the bond material. A motor (not shown) is connected to the base end (upper end) of the spindle 46. When the motor is operated, the grinding wheel 50 rotates together with the spindle 46 around a straight line along the direction in which the spindle 46 extends (here, the vertical direction) as a rotation axis.

[0085] The spindle 46 is connected to a horizontal movement mechanism (not shown) and a vertical movement mechanism (not shown). Each of these movement mechanisms includes, for example, a motor and a ball screw. When the horizontal movement mechanism is operated, the spindle 46 moves in the horizontal direction, and when the vertical movement mechanism is operated, the spindle 46 moves in the vertical direction.

[0086] In processing step S11, the spindle 46 is lowered while rotating both the chuck table 34 and the spindle 46. As a result, the grinding wheels 54 come into contact with the back surface 11c of the plate-like object 11, and the back surface 11c side of the plate-like object 11 is ground. Then, this grinding is continued until the plate-like object 11 is divided, starting from the modified portion 15.

[0087] The above-mentioned contents are examples of the present invention, and the present invention is not limited to the above-mentioned contents. For example, in the present invention, a plate-like object having a structure different from that of the plate-like object 11 may be the object to be conveyed. Fig. 15(A) is a plan view showing a schematic diagram of another example of the plate-like object, and Fig. 15(B) is a cross-sectional view showing a schematic diagram of yet another example of the plate-like object.

[0088] A plate-like object 25 shown in Fig. 15(A) is a package substrate having a rectangular shape in a plan view, and a surface 25a side of the plate-like object 25 is provided with a plurality of devices 27. A plate-like object 29 shown in Fig. 15(B) is a bonded substrate obtained by bonding together a pair of substrates 31 and 33 each made of, for example, silicon.

[0089] In the present invention, the object to be transported may be a plate-like object that is warped in an unloaded state due to processing other than processing for forming the modified portion 15. Examples of such processing include forming a plurality of devices on the front surface side of the plate-like object, grinding the back surface side, or laser processing for generating laser ablation on the front surface side.

[0090] In the present invention, a warp mitigating plate having a structure different from that of warp mitigating plate 17 may be used when transporting plate-like object 11. Fig. 16(A) is a plan view showing a schematic diagram of another example of the warp mitigating plate, and Fig. 16(B) is a plan view showing a schematic diagram of yet another example of the warp mitigating plate.

[0091] The warpage mitigating plate 35 shown in Fig. 16(A) is a circular plate having a plurality of through holes 37 formed all over the plate so as to be arranged in a matrix, while the warpage mitigating plate 39 shown in Fig. 16(B) is a circular plate having a plurality of through holes 41 formed so as to be arranged radially.

[0092] Furthermore, in the present invention, instead of or in addition to a plurality of through holes, a warpage mitigating plate including a region made of a porous body including a large number of through holes extending in the thickness direction may be used when transporting the plate-like object 11. In this case, the warpage mitigating plate is transported to move together with the plate-like object 11 while, for example, a suction force is applied from the robot hand 8 to the region made of the porous body.

[0093] Furthermore, in the present invention, a common transport unit may be used to transport the warp mitigating plate 17 alone (for example, transport of the warp mitigating plate 17 for placing the warp mitigating plate 17 on the plate-like object 11 and for separating the warp mitigating plate 17 from the plate-like object 11) and transport of the warp mitigating plate 17 for moving together with the plate-like object 11. In this case, the transport unit is configured, for example, to be capable of applying suction forces to the first region 17a and the second region 17b of the warp mitigating plate 17 independently of each other.

[0094] In the present invention, the warp mitigating plate 17 may be transported by itself using a transport unit capable of holding the warp mitigating plate 17 without applying suction force. An example of such a transport unit is a transport unit having a gripping portion capable of gripping a part of the warp mitigating plate 17 (for example, its outer peripheral region).

[0095] In addition, the structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0096] 1: Unprocessed plate-like object (1a: front side, 1b: back side) 2: Transport unit 4: First drive unit 6: Robot arm (6a: first arm, 6b: second arm, 6c: second joint) (6d: second drive unit, 6e: spindle, 6f: connection unit) 8: Robot hand 10: Main body (10a: frame, 10b: porous body) 11: Plate-like object (11a: front surface, 11b: side surface, 11c: back surface) 12: List section 13: Device 14: Flow path 15: Modification section 16a, 16b: Valve 17: Warp mitigation plate (17a: first region, 17b: second region) 18:Suction source 19:Through hole 20: Gas supply source 21: Protective tape 22: chuck table (22a: frame, 22b: porous body) 23: Protective tape 24: Flow path 25: Plate-like object (25a: surface) 26a, 26b: Valve 27: Device 28: Suction source 29: Plate-shaped object 30: Gas supply source 31: Substrate 32: Laser beam irradiation unit (32a: head) 33: Substrate 34: chuck table (34a: frame, 34b: porous body) 35: Warp relief plate 36: Flow path 37:Through hole 38a, 38b: Valve 39: Warp relief plate 40:Suction source 41:Through hole 42: Gas supply source 44: Grinding unit 46: Spindle 48: Mount 50: Grinding wheel 52: Foundation 54: Grinding wheel

Claims

1. A method for conveying a warped plate-like object in an unloaded state, comprising: an upper holding step in which a robot hand holds the plate-like object and the warp mitigating plate by applying a suction force from the robot hand through the through hole to the plate-like object on which the warp mitigating plate having a through hole is placed; a conveying step of conveying the plate-like object and the warp reducing plate by moving the robot hand that holds the plate-like object and the warp reducing plate after the upper holding step; A method for transporting a plate-like object comprising the steps of:

2. a placing step of placing the warp reducing plate on the plate-like object in a state in which the chuck table holds the plate-like object by applying a suction force from the chuck table on which the plate-like object is placed to the plate-like object; a releasing step in which, after the placing step and before the upper holding step, the chuck table releases the plate-like object by eliminating a suction force acting on the plate-like object from the chuck table; The method for conveying a plate-like object according to claim 1 , further comprising:

3. a loading step of loading an unprocessed plate-like object having a warp smaller than that of the plate-like object in an unloaded state onto the chuck table; a lower holding step in which the chuck table holds the unprocessed plate-like object by applying a suction force from the chuck table to the unprocessed plate-like object after the carrying-in step; a processing step of processing the unprocessed plate-like object so that the plate-like object is formed while the chuck table holds the unprocessed plate-like object after the lower holding step and before the placing step; The method for conveying a plate-like object according to claim 2 , further comprising:

4. a releasing step in which, after the transporting step is performed to transport the plate-like object and the warp reducing plate to a chuck table, the robot hand releases the plate-like object and the warp reducing plate by eliminating a suction force acting on the plate-like object from the robot hand through the through hole; a lower holding step in which the chuck table holds the plate-like object by applying a suction force from the chuck table to the plate-like object after the releasing step; a separation step of separating the warp reducing plate from the plate-like object while the chuck table holds the plate-like object after the lower holding step; a processing step of processing the plate-like object while the chuck table holds the plate-like object after the separating step; The method for conveying a plate-like object according to claim 1 , further comprising:

5. the warp mitigation plate is partitioned into a first region in which the through hole is formed and a second region in which the through hole is not formed, a conveyance of the warp mitigating plate for placing the warp mitigating plate on the plate-like object and for separating the warp mitigating plate from the plate-like object is performed in a state where a suction force is applied to the second region without applying a suction force to the first region; 5. The method for transporting a plate-like object according to claim 1, wherein the warp reducing plate is transported so as to move together with the plate-like object while a suction force is applied to the first region.

6. the warp mitigation plate includes a region formed of a porous body including the through holes, 5. The method for transporting a plate-like object according to claim 1, wherein the warp reducing plate is transported so as to move together with the plate-like object while a suction force is applied to the region.

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