MULTI-CASKETCH PROCESSING DEVICE THAT CAN PERFORM CONTINUOUS PROCESSING

Abstract

Machining device (1) comprising: a first cassette stage (7010) to which a first cassette (701) is attached, which holds several wafers (17); a second cassette stage (7020) to which a second cassette (702) is attached, which holds several wafers (17); a clamping table (2) which has a holding surface (200) and holds the wafer (17) on the holding surface; a processing unit (3, 5) that processes the wafer (17); a conveying mechanism (741) that conveys the wafer (17) onto the holding surface (200) of the clamping table (2); a delivery mechanism (742) that delivers the wafer (17) from the holding surface (200) of the clamping table (2); a setting section (90) which is configured to set first processing conditions for processing a wafer which is held in the first cassette (701) attached to the first cassette stage (7010), and which are used at the time of processing the wafer (17), and which is configured to set second processing conditions for processing a wafer which is held in the second cassette (702) attached to the second cassette stage (7020), and which differ from the first processing conditions and are used at the time of processing the wafer (17); a selection section (91) that is set up to select the first cassette stage (7010) or the second cassette stage (7020); a conveying control section (92) which is set up when processing of all wafers (17) that are held in a cassette (701, 702) attached to a cassette stage (7010, 7020) is completed in accordance with processing conditions corresponding to the cassette stage (7010, 7020) that has been selected by the selection section (91) and the last wafer (17) is conveyed out of the holding surface (200), thereby freeing the holding surface (200), to immediately convey a wafer (17) onto the holding surface (200) that is held in the cassette (701, 702) attached to the other cassette stage (7010, 7020); a switching section (93) which is configured to switch the processing conditions to the processing conditions corresponding to the other cassette stage (7010, 7020) when the wafer (17) to be attached to the holding surface (200) is changed from the wafer (17) that is conveyed from the side of one cassette stage (7010, 7020) to the wafer (17) that is conveyed from the side of the other cassette stage (7010, 7020), and a rotary table (23) on which several clamping tables (2) having holding surfaces (200) are arranged, which are set up to be rotatable between a feed-in position, where the wafer (17) can be conveyed onto the holding surface (200) by the feed-in mechanism (741), and a machining position, in which the machining unit (3, 5) machines the wafer (17) held by the holding surface (200), wherein, when processing of the wafers (17) is completed, after all wafers (17) held in the cassette (701, 702) attached to one cassette stage (7010, 7020) have been conveyed to the holding surface (200) and one of the several holding surfaces (200) becomes free by conveying the wafer (17) out of the holding surface (200), the conveying control section is set up to immediately convey the wafer (17) held in the cassette (701, 702) attached to the other cassette stage (7010, 7020) to the free holding surface (200).

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to a processing device. DESCRIPTION OF THE RELATED PRIOR ART

[0002] A grinding apparatus for grinding a wafer has a structure in which a cassette which accommodates wafers via trays is attached to a cassette stage, a wafer taken out from the cassette is ground by a grindstone under preset processing conditions, and the ground wafer is accommodated in the cassette.

[0003] As a grinding apparatus, as disclosed in Japanese Patent Application Laid-Open No. 2014-165434, there is one in which multiple cassette stages, such as a first cassette stage and a second cassette stage, are arranged. After the wafers housed in the cassette mounted on the first cassette stage are ground, the wafers housed in the cassette mounted on the second cassette stage are ground under the same processing conditions.

[0004] The published patent application JP 2016 - 203 362 A discloses a machining device comprising a clamping table, machining means, a cassette placement area on which cassettes for storing a plurality of workpieces are placed one above the other, an elevator for moving the cassettes in a vertical direction and thus making one of the cassettes accessible at a time, a conveyor means for transporting the workpieces between the cassettes, an intermediate storage area and the clamping table, and a control means for controlling each of these components.

[0005] Furthermore, the published patent application US 2008 / 0 090 505 A1 discloses a processing device in which a wafer is removed from a first cassette, a recess is formed in a region of a rear surface of the wafer by a rough and fine grinding unit, and the processed wafer is accommodated in a second cassette.

[0006] In recent years, there have been cases where, in order to produce multiple types of wafers in small quantities, wafers in a cassette mounted on a first cassette stage and wafers in a cassette mounted on a second cassette stage are ground by a grinder under different processing conditions. In the case of grinding wafers under different processing conditions, the processing conditions are set in the grinder, the wafers housed in the cassette mounted on the first cassette stage are ground, the ground wafers are all housed in the cassette mounted on the first cassette stage, then the processing condition setting is changed, and the wafers housed in the cassette mounted on the second cassette stage are transferred to a chuck table and ground. SUMMARY OF THE INVENTION

[0007] Therefore, until the processing conditions are changed, processing of the wafers housed in the cassette mounted on the second cassette stage cannot begin. During the period until the last wafer housed in the cassette mounted on the first cassette stage is ground and transferred from the chuck table to the cassette, and during the period until the first wafer housed in the cassette mounted on the second cassette stage is transferred, the grindstones are put on standby, resulting in low productivity. Furthermore, if the temperature in the processing chamber drops while the grindstones are on standby, the wafer thickness becomes uneven.

[0008] Accordingly, it is an object of the present invention to provide a machining apparatus in which a plurality of cassette stages are arranged and which can perform continuous machining without keeping a machining unit in a standby state.

[0009] In accordance with one aspect of the present invention, there is provided a processing apparatus comprising a first cassette stage to which a first cassette accommodating a plurality of wafers is mounted; a second cassette stage to which a second cassette accommodating a plurality of wafers is mounted; a chuck table having a holding surface and holding the wafer on the holding surface; a processing unit that processes the wafer; a feed-in mechanism that feeds the wafer onto the holding surface of the chuck table; a feed-out mechanism that feeds the wafer out from the holding surface of the chuck table;a setting section that sets first processing conditions used at the time of processing the wafer accommodated in the first cassette mounted on the first cassette stage, and second processing conditions different from the first processing conditions used at the time of processing the wafer accommodated in the second cassette mounted on the second cassette stage; a selection section that selects the first cassette stage or the second cassette stage;a conveyance control section that, when processing of all wafers accommodated in a cassette mounted on one cassette stage has been completed in accordance with processing conditions corresponding to the cassette stage selected by the selection section and the last wafer has been conveyed out from the holding surface, thereby vacating the holding surface, immediately conveys the wafer accommodated in the cassette mounted on the other cassette stage onto the holding surface; and a switching section that, when the wafer to be mounted on the holding surface is switched from the wafer conveyed out from one side of the cassette stage to the wafer conveyed out from the other side of the cassette stage, switches the processing conditions to the processing conditions corresponding to the other cassette stage.

[0010] In addition, the processing apparatus further comprises a turntable on which a plurality of chuck tables with holding surfaces are arranged and rotatably arranged between a feed-in position, where the wafer can be conveyed onto the holding surface by the feed-in mechanism, and a processing position, where the processing unit processes the wafer held by the holding surface. When processing of the wafers at the processing apparatus has been completed after all wafers accommodated in the cassette attached to one cassette stage have been conveyed onto the holding surface and one of the plurality of holding surfaces becomes vacant by conveying the wafers out of the holding surface, the conveyance control section immediately conveys the wafer accommodated in the cassette attached to the other cassette stage to the vacant holding surface.

[0011] In the processing apparatus of the present invention, the first processing conditions and the second processing conditions are preset in the setting section, and when processing of all wafers accommodated in the first cassette is completed and the holding surface becomes vacant, the wafer accommodated in the second cassette is automatically conveyed onto the holding surface under the control of the conveyance control section, so that the standby period of the processing unit can be reduced. As a result, the time required for processing the wafers can be shortened.

[0012] In addition, since it is managed which of the cassette stages the wafer is coming from and is conveyed to the holding surface, and processing conditions are switched accordingly, continuous processing of the wafers is possible even if the processing conditions differ with regard to the cassette stages.

[0013] The above and other objects, features and advantages of the present invention and the modes for carrying them out will become more apparent and the invention itself will be best understood by studying the following description and the appended claims with reference to the attached drawings which show a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing the entire part of a machining device. DETAILED EXPLANATION OF THE PREFERRED EMBODIMENT 1 Structure of a processing device

[0014] One in Fig. The processing apparatus illustrated in Figure 1 is a processing apparatus that processes a wafer 17 held by one of three chuck tables 2 by using a first processing unit 3 and a second processing unit 5. A structure of the processing apparatus 1 will be described below. The processing apparatus 1 includes a base 10, which, as shown in Fig. 1, extends in a Y-axis direction. A first column 11 is erected on the +Y direction side and the +X direction side of the base 10, and a second column 12 is erected on the -X direction side of the first column 11. Furthermore, the machining device 1 includes a housing cover 100, and various elements of the machining device 1 are covered by the housing cover 100.

[0015] A first cassette stage 7010 is arranged on the -Y direction side and on the +X direction side of the base 10, and a second cassette stage 7020 is arranged on the -X direction side of the first cassette stage 7010. A first cassette 701 is attached to the first cassette stage 7010. The first cassette 701 includes a plurality of unillustrated trays for receiving wafers 17, and, for example, a plurality of wafers 17 that have not yet been processed are received on trays in the first cassette 701. A second cassette 702 is attached to the second cassette stage 7020. The second cassette 702 includes a plurality of unillustrated trays for receiving the wafers 17, and, for example, a plurality of wafers 17 that have not yet been processed are received via trays in the second cassette 702.

[0016] A robot 71 is arranged on the +Y direction side of the first cassette 701. The robot 71 is used to pull out the wafer 17 accommodated in the first cassette 701 and transport it to an intermediate placement area 720. Furthermore, the robot 71 is used to pull out the wafer 17 accommodated in the second cassette 702 and transport it to the intermediate placement area 720.

[0017] Incidentally, the robot 71 can accommodate the processed wafer 17 in the first cassette 701 or the second cassette 702. For example, the wafer 17 taken out and processed by the robot 71 from the first cassette 701 is accommodated in the first cassette 701 after processing. On the other hand, the wafer 17 taken out and processed by the robot 71 from the second cassette 702 is accommodated in the second cassette 702 after processing.

[0018] The temporary placement area 720 where the wafer 17 that has not been processed yet is temporarily placed is provided on the +X direction side in a moving range of the robot 71, and a cleaning area 732 where the wafer 17 that has been processed is cleaned is provided on the -X direction side in the moving range of the robot 71.

[0019] An alignment mechanism 72 is arranged at the intermediate placement area 720. The wafer 17, which has been conveyed out of the cassette 70 and placed in the intermediate placement area 720, is aligned by the alignment mechanism 72 to be placed at a predetermined position.

[0020] A spin cleaning unit 73 is arranged in the cleaning area 732. The spin cleaning unit 73 includes a spin table 730 for holding the wafer 17, and a cleaning water supply nozzle 731 for ejecting cleaning water toward the wafer 17 held by the spin table 730. For example, in a state where the wafer 17 that has been processed is held on an upper surface of the spin table 730, cleaning water is supplied from the cleaning water supply nozzle 731 while the spin table 730 is rotated, whereby the wafer 17 can be cleaned. Furthermore, a waterproof cover 733 for preventing cleaning water supplied from the cleaning water supply nozzle 731 from being scattered in the vicinity of the cleaning area 732 is provided on an upper side of the spin table 730.

[0021] At a position adjacent to the intermediate placement area 720, a feed-in mechanism 741 is arranged, which feeds the wafer 17, which has been aligned at the intermediate placement area 720 using the alignment mechanism 72, onto one of the three chuck tables 2. The feed-in mechanism 741 includes a disk-shaped feed pad 75 and an arm 76 on which the feed pad 75 is suspended. The feed pad 75 is connected to a suction source (not shown), and the wafer 17 can be held by suction on a holding surface 750, which is a lower surface of the feed pad 75.

[0022] Furthermore, a shaft portion 77 is connected to one end portion of the arm 76, and an unillustrated rotation mechanism that rotates the shaft portion 77 about an axis in the Z-axis direction is connected to the shaft portion 77. By rotating the shaft portion 77 using the rotation mechanism, the arm 76 connected to the shaft portion 77 can be pivoted, and the conveying pad 75 can be moved in the horizontal direction. Further, an unillustrated lifting mechanism is arranged on the shaft portion 77. The shaft portion 77 is raised or lowered in the Z-axis direction by using the lifting mechanism, whereby the arm 76 and the conveying pad 75 are raised or lowered in the Z-axis direction as one body.

[0023] For example, in a state where the wafer 17 is placed in the temporary placement area 720, the arm 76 is pivoted to position the conveying pad 75 directly above the wafer 17 temporarily placed in the temporary placement area 720 and is lowered, after which the suction source is actuated, whereby the wafer 17 can be held by the conveying pad 75 under suction. Then, in a state where the wafer 17 is held by the conveying pad 75 via suction, the arm 76 is pivoted to place the wafer 17, which is held by the conveying pad 75 under suction, on the upper side of the chuck table 2, after which the conveying pad 75 is lowered and the suction force acting on the conveying pad 75 is released, whereby the wafer 17 can be conveyed onto the chuck table 2.

[0024] On the -X direction side of the infeed mechanism 741, a outfeed mechanism 742 is arranged, which feeds out the wafer 17 that has been processed from the chuck table 2. The outfeed mechanism 742 is constructed similarly to the infeed mechanism 741, and thus, the outfeed mechanism 742 is indicated by a symbol similar to that of the infeed mechanism 741.

[0025] For example, the wafer 17 that has been processed is held by the conveying pad 75 under suction, and the arm 76 is pivoted to position the wafer 17 held by the conveying pad 75 under suction on an upper surface of the spin table 730, after which the conveying pad 75 is lowered, and the suction force acting on the conveying pad 75 is interrupted, whereby the wafer 17 can be conveyed out from the holding surface 200 to the cleaning area 732.

[0026] A disk-shaped rotary table 23 is arranged on the +Y direction side of the base 10. The three chuck tables 2 are arranged on the upper surface 230 of the rotary table 23 at regular intervals in the circumferential direction. The rotary table 23 is connected to a rotation mechanism (not shown) and is rotatable about an axis in the Z-axis direction passing through a center point 2300 of the rotary table 23 by using the rotation mechanism.

[0027] The three chuck tables 2 are disc-shaped. The three chuck tables 2 each include a suction section 20 and a frame body 21 that supports the suction section 20. An upper surface of the suction section 20 is a holding surface 200 on which the wafer 17 is held, and an upper surface 210 of the frame body 21 is flush with the holding surface 200.

[0028] The suction section 20 is connected to a suction source (not shown). By transmitting a suction force generated by the suction source to the suction section 20 in a state in which the wafer 17 is attached to the holding surface 200, the wafer 17 can be held on the holding surface 200, for example, by suction.

[0029] In addition, a pressure monitoring means (not shown) that measures the level of pressure on the holding table 200 is connected to the holding surface 200. The pressure monitoring means measures different pressures when the wafer 17 is held on the holding surface 200 by suction and when nothing is held on the holding surface 200 in a state in which the suction source is operating.

[0030] In addition, each of the clamping tables 2 is connected to a rotation mechanism (not shown). Using the rotation mechanism, the clamping table 2 can be rotated about an axis in the Z-axis direction passing through the center of the holding surface 200.

[0031] By rotating the turntable 23, the three chuck tables 2 arranged on the turntable 23 can be rotated around the center point 2300 of the turntable 23. By rotating the chuck tables 2 using the turntable 23, each of the three chuck tables 2 can be positioned at a first processing position, which is a horizontal position on a lower side of the first processing unit 3, a second processing position, which is a horizontal position on a lower side of the second processing unit 5, and a feed-in position, which is a horizontal position at the time of conveying the wafer 17 onto the holding surface 200 by using the feed-in mechanism 741 (as well as a feed-out position at the time of feeding the wafer 17 out by using the feed-out mechanism 742).

[0032] Here, the first processing position is a horizontal position of the chuck table 2 at the time of rough grinding the wafer 17 by using the first processing unit 3, and the second processing position is a horizontal position of the chuck table 2 at the time of finish grinding the wafer 17 by using the second processing unit 5. For example, when one of the three chuck tables 2 is positioned at the first processing position, the other two chuck tables 2 are positioned at the second processing position and the feed-in position, respectively.

[0033] On a side surface on the -Y direction side of the first column 11, a first machining feed mechanism 4 is arranged, which supports the first machining unit 3 in a raisable and lowerable manner. The first machining feed mechanism 4 includes a ball screw 40 having a rotation axis 45 in the Z-axis direction, a pair of guide rails 41 arranged parallel to the ball screw 40, a Z-axis motor 42 that rotates the ball screw 40 about the rotation axis 45, a lifting plate 43 with a nut arranged therein and threadedly engaged with the ball screw 40 and having side portions in slidable contact with the guide rails 41, and a bracket 44 connected to the lifting plate 43 and supporting the first machining unit 3.

[0034] When the ball screw 40 is driven by the Z-axis motor 42 and the ball screw 40 is rotated about the rotation axis 45, the lifting plate 43 is raised or lowered accordingly in the Z-axis direction while being guided by the guide rails 41, and the first machining unit 3 is raised or lowered in the Z-axis direction.

[0035] The first processing unit 3 is, for example, a rough grinding unit including a spindle 30 having a rotation axis in the Z-axis direction, a housing 31 that rotatably supports the spindle 30, a spindle motor 32 that rotates the spindle 30 around the rotation axis 35, a holder 33 connected to a lower end of the spindle 30, and a rough grinding wheel 34 detachably attached to a lower surface of the holder 33. The rough grinding wheel 34 includes a wheel base 341 and a plurality of substantially rectangular, cuboid-shaped rough grinding stones 340 arranged in an annular pattern on a lower surface of the wheel base 341. Lower surfaces 342 of the rough grinding stones 340 are grinding surfaces that contact an upper surface 170 of the wafer 17.

[0036] When the spindle 30 is rotated by using the spindle motor 32, the bracket 33 connected to the spindle 30 and the rough grinding wheel 34 attached to the lower surface of the bracket 33 are rotated as one body.

[0037] A first thickness measuring unit 13 is arranged in the vicinity of the first processing unit 3 on the base 10. The first thickness measuring unit 13 includes, for example, a contact height gauge or the like, and can measure the thickness of the wafer 17 by bringing the height gauge into contact with the upper surface 170 of the wafer 17 held on the holding surface 200 and with the upper surface 210 of the frame body 21 and measuring the height difference between them during rough grinding of the wafer 17.

[0038] On a side surface on the -Y direction side of the second column 12, a second machining feed mechanism 6 is arranged, which supports the second machining unit 5 in a raisable and lowerable manner. The second machining feed mechanism 6 includes a ball screw 60 having a rotation axis 65 in the Z-axis direction, a pair of guide rails 61 arranged parallel to the ball screw 60, a Z-axis motor 62 that rotates the ball screw 60 about the rotation axis 65, a lifting plate 63 having a nut inside and threadedly engaged with the ball screw 60 and having side portions in slidable contact with the guide rails 61, and a bracket 64 connected to the lifting plate 63 and supporting the second machining unit 5.

[0039] When the ball screw 60 is driven by the Z-axis motor 62 and rotated around the rotation axis 65, the lifting plate 63 is raised or lowered accordingly while being guided by the guide rails 61, and the second machining unit 5 held by the bracket 64 is raised or lowered in the Z-axis direction.

[0040] The second machining unit 5 is, for example, a finish grinding unit including a spindle 50 having a rotation axis 55 in the Z-axis direction, a housing 51 that supports the spindle 50 in a rotatable manner, a spindle motor 52 that drives the spindle 50 in a rotational manner around the rotation axis 55, a bracket 53 connected to a lower end of the spindle 50, and a finish grinding wheel 54 detachably attached to a lower surface of the bracket 53.

[0041] The finishing grinding wheel 54 includes a wheel base 541 and a plurality of substantially rectangular, cuboid-shaped finishing grinding stones 540 arranged in an annular pattern on a lower surface of the wheel base 541. Here, the abrasive grains of the finishing grinding stones 540 are finer than the abrasive grains of the coarse grinding stones 340. Lower surfaces 542 of the finishing grinding stones 540 are grinding surfaces that contact the upper surface 170 of the wafer 17.

[0042] When the spindle 50 is rotated by using the spindle motor 52, the bracket 53 connected to the spindle 50 and the finishing grinding wheel 54 attached to the lower surface of the bracket 53 are rotated as one body.

[0043] A second thickness measuring unit 14 is arranged in the vicinity of the second processing unit 5 on the base 10. The second thickness measuring unit 14 includes, for example, a contact height gauge or the like, which is similar to the first thickness measuring unit 13. The thickness of the wafer 17 can be measured by bringing the height gauge into contact with the upper surface 170 of the wafer 17, which is held by the holding surface 200, and the upper surface 210 of the frame body 21, and measuring the height difference between them during the finish grinding of the wafer 17.

[0044] The processing apparatus 1 includes a setting section 90 that sets first processing conditions for processing the wafer 17 accommodated in the first cassette 701 mounted on the first cassette stage 7010 and second processing conditions for processing the wafer 17 accommodated in the second cassette 702 mounted on the second cassette stage 7020. The setting section 90 includes, for example, a storage element such as a memory that has an area for storing the first processing conditions and an area for storing the second processing conditions. The first processing conditions and the second processing conditions are different processing conditions.A touch panel 15 is provided on a side surface on the -Y direction side of the housing cover 100 of the machining device 1, and the touch panel 15 is electrically connected to the setting section 90. For example, by touching the touch panel 15 to set the machining conditions, the set machining conditions are stored in the setting section 90.

[0045] Furthermore, the processing apparatus 1 includes a selecting section 91 that selects the first cassette stage 7010 or the second cassette stage 7020. The processing apparatus 1 includes a conveying control section 92 that, when processing of all the wafers accommodated in the first cassette 701 attached to the first cassette stage 7010 or the second cassette 702 attached to the second cassette stage 7020 selected by the selecting section 91 is completed, and the last wafer 17 has been conveyed out from the holding surface 200, leaving the holding surface 200 vacant, executes control to immediately convey the wafer 17 accommodated in the other cassette onto the holding surface 200.

[0046] The above-mentioned unillustrated pressure monitoring means is electrically connected to the conveyance control section 92. Furthermore, an unillustrated detection means that detects the number of wafers 17 previously stored in the first cassette 701 and an unillustrated counter that counts the number of wafers 17 pulled out and processed from the first cassette 701 are connected to the conveyance control section 92. The counter has, for example, a function of incrementing each time the pressure on the holding surface 200 changes as the wafer 17 is conveyed away from the holding surface 200.

[0047] In the conveyance control section 92, the time at which processing of the last wafer 17 is to be completed is determined based on the number of wafers 17 previously received in the first cassette 701, which is detected by the detection means, and the number of processed wafers 17, which is counted by the counter. When the last wafer 17 has been conveyed away from the holding surface 200 and the holding surface 200 becomes vacant, emptiness is detected by a change in pressure monitored by the pressure monitoring means, and is transmitted as an electrical signal to the conveyance control section 92.

[0048] The vacancy of the holding surface 200 can be detected when the number of wafers 17 previously held in the first cassette 701, which is detected by the detection means, and the number of processed wafers 17, which is counted by the counter, agree with each other. Furthermore, the pressure monitoring means and the counter can be arranged at the carrying-out mechanism 742 that carries out the wafer 17 from the holding surface. The counter can be caused to count up by a pressure change detected by the pressure monitoring means when the wafer 17 is held by the carrying-out mechanism 742. The vacancy of the holding surface 200 can be detected when the counted value agrees with the number of wafers 17 that have been held in the first cassette 701.

[0049] Further, the processing apparatus 1 includes a switching section 93 that switches the processing conditions to the processing conditions corresponding to the other cassette stage when the wafer 17 held by the holding surface 200 is to be switched from the wafer 17 conveyed from the first cassette stage 7010 or the second cassette stage 7020 to the wafer 17 conveyed from the other cassette stage. The switching section 93 reads the first processing conditions or the second processing conditions from the setting section 90 and uses the read processing conditions to control the processing apparatus 1. 2 Operation of the processing device

[0050] An operation of the processing apparatus 1 when the wafer 17 is processed by using the processing apparatus 1 will now be described. As a processing order, a case where all the wafers 17 accommodated in the first cassette 701 are processed first, and then the wafers 17 accommodated in the second cassette 702 are processed, will be described as an example.

[0051] To process the wafers 17 accommodated in the first cassette 701 using the processing apparatus 1, the first cassette stage 7010 is first selected by the selecting section 91. As a result, the first processing conditions set in the setting section 90 as processing conditions corresponding to the first cassette stage 7010 are read out. The first processing conditions include, for example, rotation speeds of the rough grinding stones 340 and the finishing grinding stones 540, and processing feed speeds of both grinding stones.

[0052] Then, one of the plurality of wafers 17 accommodated in the first cassette 701 is taken out by using the robot 71 and placed in the intermediate placement area 720 and subjected to alignment using the alignment mechanism 72.

[0053] Further, the turntable 23 is rotated, whereby one of the three chuck tables 2 disposed on the turntable 23 is positioned at the feed-in position of the wafer 17. In a state where one of the three chuck tables 2 is positioned at the feed-in position, the wafer 17 placed in the intermediate placement area 720 is conveyed onto the holding surface 200 of the chuck table 2 positioned at the feed-in position by using the feed-in mechanism 741. Next, in a state where the wafer 17 is attached to the holding surface 200, the unillustrated suction source is actuated, whereby the generated suction force is transmitted to the holding surface 200, and the wafer 17 is held on the holding surface 200 by suction.

[0054] Subsequently, the turntable 23 is rotated, for example, by 120° counterclockwise, whereby the chuck table 2 with the wafer 17 held on its holding surface 200 is moved to a position on a lower side of the first processing unit 3. As a result, the chuck table 2 with the wafer 17 held on its holding surface 200 is positioned at the first processing position.

[0055] In addition, the wafer 17 held on the holding surface 200 of the chuck table 2 is rotated by an unillustrated rotation mechanism, and the rough grinding stones 340 are rotated about the rotation axis 35 in advance by using the spindle motor 32.

[0056] In a state where the wafer 17 held by the holding surface 200 and the rough grinding stones 340 are rotated, the rough grinding stones 340 are lowered in the -Z direction by using the first processing feed mechanism 4. As a result, the lower surfaces 342 of the rough grinding stones 340 are brought into contact with the upper surface 170 of the wafer 17.

[0057] In a state where the lower surfaces 342 of the rough grinding stones 340 are in contact with the upper surface 170 of the wafer 17, the rough grinding stones 340 are gradually lowered further in the -Z direction by using the first processing feed mechanism 4, thereby roughly grinding the wafer 17. During the rough grinding of the wafer 17, a measurement of the thickness of the wafer 17 is performed using the first thickness measuring unit 13. When the wafer 17 is ground to a predetermined thickness, the rough grinding of the wafer 17 is terminated.

[0058] After the rough grinding of the wafer 17 is completed, the rough grinding stones 340 are lifted in the +Z direction by using the first processing feed mechanism 4, whereby the rough grinding stones 340 are separated from the upper surface 170 of the wafer 17.

[0059] Then, the turntable 23 is rotated, for example, by 120° counterclockwise, thereby moving the chuck table 2 with the roughly ground wafer 17 held thereon to a position on a lower side of the second processing unit 5. As a result, the chuck table 2 with the roughly ground wafer 17 held thereon is positioned at the second processing position.

[0060] In addition, the finishing grindstones 540 are rotated about the rotation axis 55 in advance by using the spindle motor 52. In a state where the wafer 17 held on the holding surface 200 and the finishing grindstones 540 are rotated, the finishing grindstones 540 are lowered in the -Z direction by using the second processing feed mechanism 6, thereby bringing the lower surfaces 542 of the finishing grindstones 540 into contact with the upper surface 170 of the wafer 17. In a state where the lower surfaces 542 of the finishing grindstones 540 are in contact with the upper surface 170 of the wafer 17, the finishing grindstones 540 are further lowered in the -Z direction by using the second processing feed mechanism 6, thereby finish-grinding the wafer 17.

[0061] During the finish grinding of the wafer 17, a thickness measurement of the wafer 17 is performed using the second thickness measuring unit 14. When the wafer 17 has been finish ground to a predetermined thickness, the finish grinding of the wafer 17 is finished. After the finish grinding of the wafer 17 is finished, the finishing grindstones 540 are lifted in the +Z direction using the second processing feed mechanism 6, thereby separating the finishing grindstones 540 from the upper surface 170 of the wafer 17.

[0062] Then, the turntable 23 is rotated, for example, by 120° counterclockwise, thereby positioning the chuck table 2 with the finished-ground wafer 17 held thereon in the carry-out area (the same as the carry-in area). In a state where the chuck table 2 with the finished-ground wafer 17 held thereon is positioned in the carry-out area, the wafer 17 is carried out from the holding surface 200 onto the spin table 730 by using the carry-out mechanism 742.

[0063] Then, in a state where the wafer 17 is held on the spin table 730, cleaning water is ejected from a cleaning water supply nozzle 731 while the spin table 730 is rotated, whereby the upper surface 170 of the wafer 17 is cleaned with the running water.

[0064] After cleaning the upper surface 170 of the wafer 17 with running water, the wafer 17 is picked up in the first cassette 701 by using the robot 71.

[0065] In the above-mentioned sequence of processing operations, immediately after the chuck table 2 with the wafer 17 held thereon is moved to a position on a lower side of the first processing unit 3, the wafer 17 is transferred as the next workpiece to be processed onto the chuck table 2, which is positioned at the feed-in position at that time. Consequently, the wafers 17 accommodated in the first cassette 701 are taken out one by one and are subjected to rough grinding by using the first processing unit 3 and finish grinding by using the second processing unit 5. The number of wafers 17 accommodated in the first cassette 701 is detected in advance, and the number of rough-ground and finish-ground wafers 17 is counted.

[0066] When the final grinding of the last wafer 17, which is among the wafers 17 accommodated in advance in the first cassette 701, is completed and the last wafer 17 has been carried out from the holding surface 200 of the chuck table 2 by the carrying-out mechanism 742, the holding surface 200 of the chuck table 2 becomes free.

[0067] Here, the above-described, unillustrated pressure monitoring means is connected to the holding surface 200, and a change in the magnitude of the suction force on the holding surface 200 is monitored. When changing from a state in which the last wafer 17 is held on the holding surface 200 by suction to a state in which the last wafer 17 has been carried out from the holding surface by the carrying-out mechanism 742 and nothing is held on the holding surface 200, the magnitude of the suction force on the holding surface 200 changes. The pressure change is transmitted as an electrical signal to the conveyance control section 92.

[0068] When the electrical signal is transmitted to the conveyance control section 92, the second cassette stage 7020 is selected by the selection section 91. In response to operation control by the conveyance control section 92, the wafer 17 accommodated in the second cassette 702 attached to the second cassette stage 7020 is then pulled out by the robot 71 and placed in the intermediate placement area 720. Then, alignment of the wafer 17 is performed using the alignment mechanism 72.

[0069] After the alignment of the wafer 17 is performed, the wafer 17 is conveyed onto the chuck table 2 in a state where the chuck table 2 is positioned in advance in the conveyance area by using the conveyance-in mechanism 741. When the wafer 17 to be held on the holding surface 200 is switched from the first cassette 701 placed on the first cassette stage 7010 to the wafer 17 accommodated in the second cassette 702 placed on the cassette stage 7020, the second processing conditions are read out from the setting section 90, and processing conditions are switched from the first processing conditions to the second processing conditions, which are processing conditions corresponding to the second cassette stage 7020, by the switching section 93.

[0070] Thereafter, the wafer 17 is roughly ground by using the first processing unit 3 and then finish ground by using the second processing unit 5 similarly to the above-described manner, and the wafer 17 is carried out from the holding surface 200 onto the spin table 730 by using the carry-out mechanism 742, followed by cleaning the upper surface 170 of the wafer 17 with running water by using the spin cleaning unit 73 and picking up the wafer 17 in the second cassette 702 by using the robot 71.

[0071] Further, the wafers 17 accommodated in the second cassette 702 are successively pulled out and are sequentially subjected to rough grinding by using the first processing unit 3 and finish grinding by using the second processing unit 5, whereby all the wafers 17 previously accommodated in the second cassette 702 are processed.

[0072] In the processing according to the prior art, after processing of the wafers 17 under one processing condition is completed, a new processing condition is set for processing the wafers 17 under a different processing condition, which has been a bottleneck. On the other hand, in the processing apparatus 1, first processing conditions and second processing conditions are set in advance in the setting section 90, and when processing of all the wafers 17 accommodated in the first cassette 701 is completed and the holding surface 200 becomes vacant, the wafers 17 accommodated in the second cassette 702 are automatically conveyed to the holding surface 200 under control using the conveyance control section 92, so that the length of the waiting time of the first processing unit 3 and the second processing unit 5 can be reduced.Accordingly, the time required to process the wafers 17 can be shortened.

[0073] In addition, since it is managed from which of the cassette stages the wafer 17 that is conveyed onto the holding surface 200 comes, and processing conditions are switched by the switching section 93, continuous processing of the wafers 17 is possible even if the processing conditions are different depending on the cassette.

[0074] It should be noted that the processing apparatus 1 is not limited to the above-described grinding apparatus for grinding the wafers 17, and may be a polishing apparatus for polishing the wafers 17 or a cutting apparatus for cutting the wafers 17.

Claims

[1] Processing device (1) comprising: a first cassette stage (7010) to which a first cassette (701) is mounted, which holds a plurality of wafers (17); a second cassette stage (7020) to which a second cassette (702) is mounted, which holds a plurality of wafers (17); a chuck table (2) having a holding surface (200) and holding the wafer (17) on the holding surface; a processing unit (3, 5) that processes the wafer (17); a feed-in mechanism (741) that feeds the wafer (17) onto the holding surface (200) of the chuck table (2); a discharge mechanism (742) that discharges the wafer (17) from the holding surface (200) of the chuck table (2); a setting section (90) configured to set first processing conditions for processing a wafer accommodated in the first cassette (701) attached to the first cassette stage (7010) and used at the time of processing the wafer (17), and configured to set second processing conditions for processing a wafer accommodated in the second cassette (702) attached to the second cassette stage (7020), which are different from the first processing conditions and used at the time of processing the wafer (17); a selecting section (91) configured to select the first cassette stage (7010) or the second cassette stage (7020); a conveyance control section (92) configured, when processing of all wafers (17) accommodated in a cassette (701, 702) mounted on one cassette stage (7010, 7020) is completed in accordance with processing conditions corresponding to the cassette stage (7010, 7020) selected by the selecting section (91) and the last wafer (17) is conveyed out from the holding surface (200), thereby freeing the holding surface (200), to immediately convey a wafer (17) accommodated in the cassette (701, 702) mounted on the other cassette stage (7010, 7020) onto the holding surface (200); a switching section (93) configured to switch the processing conditions to the processing conditions corresponding to the other cassette stage (7010, 7020) when the wafer (17) to be mounted on the holding surface (200) is changed from the wafer (17) conveyed out from the side of one cassette stage (7010, 7020) to the wafer (17) conveyed out from the side of the other cassette stage (7010, 7020), and a turntable (23) on which a plurality of clamping tables (2) having the holding surfaces (200) are arranged, which are configured to be rotatable between a feed-in position, where the wafer (17) can be conveyed onto the holding surface (200) by the feed-in mechanism (741), and a processing position, in which the processing unit (3, 5) processes the wafer (17) held by the holding surface (200), wherein, when processing of the wafers (17) is completed after all the wafers (17) accommodated in the cassette (701, 702) attached to the one cassette stage (7010, 7020) have been conveyed onto the holding surface (200) and one of the plurality of holding surfaces (200) becomes free by conveying out the wafer (17) from the holding surface (200), the conveyance control section is arranged to immediately convey the wafer (17) accommodated in the cassette (701, 702) attached to the other cassette stage (7010, 7020) onto the free holding surface (200).

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