Machining device for determining whether a workpiece machined by it has been properly machined or not

Abstract

Machining device (1) comprising: a clamping table (30) for holding a workpiece (80) which has a marking (805) representing a crystal orientation, on a holding surface (302) of this; a processing unit (16) for grinding the workpiece (80) held on the clamping table (30) with grinding stones or for polishing the workpiece (80) held on the clamping table (30) with a polishing pad; a cassette stage (150, 151) for placing a cassette (21, 22) on it for storing several workpieces (80) on their respective shelves; an intermediate storage table (11) for temporarily placing a workpiece (80) on it; a centrifugal table (120) for holding a workpiece (80) to be cleaned on it; a robot (14) for feeding a workpiece (80) from the cassette (21, 22) placed on the cassette stage (150, 151) to the intermediate storage table (11) or for feeding a workpiece (80) held on the centrifugal table (120) into the cassette (21, 22) placed on the cassette stage (150, 151); a determination section (90) for determining whether a workpiece (80) has been properly machined or not properly machined; and a control unit (9) for performing a control operation to align the marking (805) of the workpiece (80) in a predetermined direction when the determination section (90) determines that the workpiece (80) has been properly machined, and storing the workpiece (80) in the cassette (21, 22), and for performing a control operation to align the marking (805) of the workpiece (80) in a direction deviating from the predetermined direction when the determination section (90) determines that the workpiece (80) has not been properly machined, and storing the workpiece (80) in the cassette (21, 22), wherein the control unit (9) is configured to rotate the centrifugal table (120) with the workpiece (80) held on it under suction by a predetermined angle in order to align the marking (805) of the workpiece (80).

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to an apparatus for processing a workpiece such as a semiconductor wafer, and more particularly to a processing apparatus capable of determining whether or not a workpiece processed thereby has been properly processed. DESCRIPTION OF THE RELATED PRIOR ART

[0002] For example, a fully automatic grinding device for grinding a workpiece with grindstones to thin the workpiece (see, for example, the disclosure of JP 2015-213995 A) comprises a cassette stage for placing thereon a cassette accommodating a plurality of workpieces on respective shelves, an intermediate storage table for temporarily placing a workpiece thereon, a chuck table having a holding surface for holding a workpiece thereon, a grinding unit for grinding a workpiece held on the chuck table with grindstones, a spin table for holding a workpiece that has been ground while it is being cleaned, a robot for feeding a workpiece from the cassette to the intermediate storage table or feeding a workpiece from the spin table to the cassette,a first feed mechanism for feeding a workpiece from the intermediate storage table to the clamping table and a second feed mechanism for feeding a workpiece from the clamping table to the spinning table.,

[0003] Japanese Unexamined Patent Application JP 2015-213995 A relates to a method for supplying a grinding fluid to a processing location where the grinding surface of a grindstone and a workpiece come into contact in a grinding apparatus. Furthermore, Japanese Unexamined Patent Application US 5,611,655 A discloses a vacuum processing apparatus capable of performing a predetermined vacuum processing operation on a semiconductor wafer, a vacuum processing method, and a technique for detecting whether a wafer has been properly processed. SUMMARY OF THE INVENTION

[0004] Workpieces have an alignment plane or alignment notch that indicates their crystal alignment. Workpieces that have been ground are returned to the cassette with their alignment planes aligned, regardless of whether they have been properly ground. Consequently, the operator operating the grinding device is unable to visually verify whether a workpiece returned to the cassette has been properly machined.One solution was to display workpiece data about each of the workpieces placed on respective trays in the cassette, as detected by the grinding device, on a display screen, such as a touch panel, of the cassette. This allows the operator to perform a workpiece removal operation to remove an improperly machined workpiece from the workpieces stored in the cassette while referring to the workpiece data displayed on the display screen and visually comparing the actual trays in the cassette and the displayed workpiece data. However, such a workpiece removal operation was cumbersome and time-consuming.

[0005] It is therefore an object of the present invention to provide a machining device that enables the worker to quickly and easily recognize, by viewing the interior of the cassette, whether machined workpieces placed on respective trays in a cassette have been properly machined or not.

[0006] According to one aspect of the present invention, a machining apparatus is provided. The machining apparatus comprises a chuck table for holding a workpiece having a mark representing a crystal orientation on its holding surface, a machining unit for grinding the workpiece held on the chuck table with grindstones or polishing the workpiece held on the chuck table with a polishing pad, a cassette stage for placing thereon a cassette for storing a plurality of workpieces on respective shelves, an intermediate storage table for temporarily placing a workpiece thereon, a spin table for holding a workpiece to be cleaned, a robot for feeding a workpiece from the cassette placed on the cassette stage to the intermediate storage table or for feeding a workpiece held on the spin table into the cassette placed on the cassette stage,a determination section for determining whether a workpiece has been properly machined or improperly machined, and a control unit for executing a control operation for aligning the mark of the workpiece in a predetermined direction when the determination section determines that the workpiece has been properly machined and storing the workpiece in the cassette, and for executing a control operation for aligning the mark of the workpiece in a direction deviating from the predetermined direction when the determination section determines that the workpiece has not been properly machined and storing the workpiece in the cassette, wherein the control unit is configured to rotate the spin table with the workpiece held thereon under suction by a predetermined angle to align the mark of the workpiece.

[0007] Preferably, the machining apparatus further comprises a thickness measuring unit for measuring the thickness of the workpiece, in which the determination section determines whether the workpiece has been properly machined or improperly machined based on the thickness of the workpiece measured by the thickness measuring unit.

[0008] Preferably, the determination section comprises a plurality of determination sections, the direction deviating from the predetermined direction comprises different directions which are preset in association with the respective determination sections as not being in agreement with each other, the determination sections determine whether the workpiece has been properly machined or improperly machined in accordance with respective different determination criteria, and when at least one of the determination sections determines that the workpiece has been improperly machined, the control unit executes a control operation for aligning the mark of the workpiece in the direction preset in accordance with the associated determination section which determines that the workpiece has been improperly machined, and stores the workpiece in the cassette.

[0009] The machining apparatus in accordance with the aspect of the present invention includes the determining section for determining whether a workpiece has been properly machined or improperly machined, and the control unit for executing the control operation for aligning the mark of the workpiece in the predetermined direction when the determining section determines that the workpiece has been properly machined and storing the workpiece in the cassette, and for executing the control operation for aligning the mark of the workpiece in the direction deviated from the predetermined direction when the determining section determines that the workpiece has been improperly machined and storing the workpiece in the cassette.Therefore, the worker can easily determine whether the workpiece has been properly machined or improperly machined by observing the alignment of the mark on the workpiece stored in the cassette. The worker can then easily remove only the improperly machined workpiece without having to laboriously view workpiece data on a fixture's display screen. Consequently, the worker can feed the cassette, from which improperly machined workpieces have been removed, to a fixture during the next processing step.

[0010] In a case where the machining apparatus further includes the thickness measuring unit for measuring the thickness of a workpiece, and the determining section determines whether the workpiece has been properly machined or improperly machined based on the thickness of the workpiece measured by the thickness measuring unit, the control unit can easily execute the control operation for aligning the mark of the workpiece in the predetermined direction or the control operation for aligning the mark of the workpiece in the direction deviating from the predetermined direction.

[0011] The determination section may include a plurality of determination sections. The direction deviating from the predetermined direction may include different directions preset in association with the respective determination sections as not being consistent with each other. The determination sections may determine whether the workpiece has been properly machined or improperly machined according to different determination criteria. In this case, if at least one of the determination sections determines that the workpiece has been improperly machined, the control unit executes the control operation for aligning the mark of the workpiece in the direction preset in association with the determination section that determines that the workpiece has been improperly machined, and stores the workpiece in the cassette.Therefore, the worker can easily know whether the workpiece has been properly machined or improperly machined by observing the orientation of the mark of the workpiece stored in the cassette and can recognize the nature of an abnormality of the workpiece that has not been properly machined.

[0012] 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 appended claims with reference to the attached drawings which show a preferred embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view illustrating, by way of example, a machining apparatus in accordance with an embodiment of the present invention; Fig. 2 is a perspective view illustrating, by way of example, a second cassette and a second cassette stage of the processing apparatus; Fig. 3 is a perspective view illustrating the manner in which a ground workpiece held by suction on a spin table is unloaded by a robot hand; Fig. 4 is a perspective view illustrating a workpiece stored in the second cassette after a control unit has performed a control operation for aligning a mark on a workpiece in a proper machining direction; Fig. 5 is a perspective view illustrating a workpiece stored in the second cassette after a control unit has executed a control operation for aligning a mark on a workpiece machining thickness anomaly direction; and Fig. 6 is a perspective view illustrating a workpiece stored in the second cassette after a control unit executes a control operation for aligning a mark on a workpiece in a machining crack anomaly direction, etc. DETAILED EXPLANATION OF THE PREFERRED EMBODIMENT

[0013] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

[0014] One in Fig. The machining apparatus 1 illustrated in FIG. 1 in accordance with the preferred embodiment of the present invention is a grinding apparatus for grinding a workpiece 80 held on a chuck table 30, having a machining unit 16. For the purpose of supplying a reference alignment frame to the machining apparatus 1, there are mutually perpendicular X-axis directions, Y-axis directions, and Z-axis directions, which will be described and illustrated with respect to various components of the machining apparatus 1. The X-axis directions include a +X direction and a -X direction as opposite directions, the Y-axis directions include a +Y direction and a -Y direction as opposite directions, and the Z-axis directions include a +Z direction and a -Z direction as opposite directions.

[0015] It should be noted that the machining device 1 has a base 10, above which a front portion extends in the -Y direction as a loading / unloading portion 100 for loading a workpiece 80 onto the chuck table 30 and unloading a workpiece 80 from the chuck table 30, and above which a rear portion extends in the +Y direction as a machining portion 101 for performing a grinding operation with the machining unit 16 on a workpiece 80 held on the chuck table 30.

[0016] The machining apparatus 1 according to the present invention may be arranged to include, as a machining unit, two grinding units including a rough grinding unit and a finish grinding unit, and a rotary table for positioning the chuck table 30 with the workpiece 80 held thereon under each of the grinding units. Alternatively, the machining apparatus according to the present invention may be arranged to include, as a machining unit, a polishing unit for polishing a workpiece with a polishing pad to finish a target surface of the workpiece 80 to a mirror finish or to increase the bending strength of the workpiece 80.

[0017] The machining device 1 includes a control unit 9 for controlling its components. The control unit 9 includes a central processing unit (CPU) for executing arithmetic processing operations in accordance with control programs and a storage device, such as a memory. The control unit 9 is electrically connected to the components of the machining unit 16 to control the components.

[0018] In accordance with the present embodiment, the Fig. 1, the workpiece 80 illustrated is a circular semiconductor wafer made of a base material of silicon or the like. The workpiece 80 has a front side 801 which is Fig. 1 with a plurality of components formed thereon is facing downwards. The end face 801 is protected by a protective band (not shown) attached thereto. The workpiece 80 has a rear side 802 which is Fig. 1 is facing upward and is a target surface to be ground. It should be noted that the workpiece 80 may be formed of gallium arsenide, sapphire, gallium nitride, resin, ceramic, silicon carbide, or the like instead of silicon.

[0019] The workpiece 80 has an alignment plane, as a mark indicating its crystal orientation, formed in an outer peripheral portion thereof by removing a portion of the outer peripheral portion, leaving an arcuate recess with a flat edge. The mark 805 may be in the form of a notch indicating the crystal orientation. The notch may be a recess formed in an outer peripheral edge of the workpiece 80 as a recess radially inward toward the center of the workpiece 80.

[0020] A first cassette stage 150 and a second cassette stage 151 for respectively placing cassettes, each storing a plurality of workpieces 80 on respective trays therein, are arranged on a front wall of the base 10 facing the -Y direction. A first cassette 21, in which a plurality of workpieces 80 to be machined are stored on respective trays therein, is placed on the first cassette stage 150. A second cassette 22, in which a plurality of workpieces 80 that have been machined are stored on respective trays therein, is placed on the second cassette stage 151.

[0021] Since the second cassette 22 and the first cassette 21 are substantially identical in structure to each other, the structure of the second cassette 22 will be described hereinafter, whereas the structure of the first cassette 21 will not be described hereinafter.

[0022] For example, the second cassette 22, which has the trays for storing a plurality of workpieces 80 that have been machined, i.e., ground, thereon, is also known as a Closed Front Opening Unified Pod (FOUP). The second cassette 22 includes at least an upper plate 222 supporting a handle 228 on its upper surface that can be grasped by a worker, two side plates 223 and 224 extending downward in the -Z direction from opposite side edges of the upper plate 222 and facing each other horizontally, a rear plate 225 connected to respective rear edges of the side plates 223 and 224, a plurality of trays 226 facing each other in the X-axis directions and formed on inner side surfaces of the side plates 223 and 224 for storing a plurality of workpieces 80, and a lower plate 225.Base plate 227 connecting the respective lower ends of the side plates 223 and 224 and the rear plate 225.

[0023] The shelves 226 for storing the respective workpieces 80 are spaced at predetermined intervals in the Z-axis directions in the vertical direction and have central access openings for a Fig. 1 to enter through the access openings toward the trays 226. The trays 226 support outer peripheral portions of the workpieces 80. The robot 14 can move from the access openings to positions directly beneath the workpieces 80 stored in the trays 226. Note that, in accordance with the present embodiment, the second cassette 22 is closed to protect against the entry of dirt and dust. However, the second cassette 22 may be an open cassette.

[0024] As in Fig. 2, the second cassette 22 has a front opening 220 open in the +Y direction. The front opening 220 is defined by respective front edges of the top plate 222, the side plates 223 and 224, and the bottom plate 227. Workpieces 80 can be loaded into and unloaded from the second cassette 22 through the front opening 220 via the robot 14 as it enters the access openings of the trays 226. When the second cassette 22 itself is sent from the processing device 1 to another device in a next processing step, the front opening 220 is closed, for example, by a cassette cover (not shown). When workpieces 80 are to be removed from the second cassette 22, an opening / closing handle on the cassette lid is rotated by an unillustrated opening / closing mechanism or the like of the machining device 1, which opens the cassette lid.

[0025] Four cassette holders 1511 for preventing the second cassette 22 placed on an upper surface of the second cassette stage 151 from being displaced horizontally parallel to a plane defined by the X-axis and Y-axis directions are arranged on the upper surface of the cassette stage 151 in alignment with respective four corners of the bottom plate 227 of the second cassette 22.

[0026] As in Fig. 1, the machining apparatus 1 includes an intermediate storage table 11 for temporarily placing a workpiece 80 thereon, a spin table 120 for holding and rotating a workpiece 80 while being cleaned, and the robot 14 for feeding a workpiece 80 from the first cassette 21 placed on the first cassette stage 150 onto the intermediate storage table 11 or feeding a workpiece 80 from the spin table 120 into the second cassette 22 placed on the second cassette stage 151.

[0027] As in Fig. 1, the robot 14 is arranged behind the opening 210 of the first cassette 21, which is open in the +Y direction. The robot 14 is, for example, a multi-joint robot and includes a robot hand 140 having a suction surface 1404 for holding a workpiece 80 thereon via suction, a horizontal hand movement mechanism 142 for horizontally moving the robot hand 140, a vertical hand movement mechanism 144, such as an electric actuator, for vertically moving the robot hand 140, and a hand rotation mechanism 146 for vertically rotating the suction surface 1404 of the robot hand 140.

[0028] The horizontal hand movement mechanism 142 is, for example, a structure for rotating a swing arm formed with a plurality of plate-shaped arm members or the like and including a cable mechanism therein, with a swing motor. Specifically, the horizontal hand movement mechanism 142 can rotate the robot hand 140 in a horizontal plane defined by the X-axis and Y-axis directions by rotating the plate-shaped arm members relative to each other about rotation axes whose axes extend in the Z-axis direction, i.e., the vertical direction. Furthermore, the horizontal hand movement mechanism 142 can change its shape from a state where the plate-shaped arm members cross each other to a state where the plate-shaped arm members are aligned with each other, etc., thereby causing the robot hand 140 to perform a linear movement in the horizontal plane.

[0029] The vertical hand movement mechanism 144 is connected to a lower portion of the horizontal hand movement mechanism 142. The vertical hand movement mechanism 144 can cooperate with the horizontal hand movement mechanism 142 to move the robot hand 140 vertically in the Z-axis directions to position the robot hand 140 at a predetermined height.

[0030] A housing 1463 is fixedly mounted to one of the plate-shaped arm members of the horizontal hand-rotating mechanism 142 via a columnar arm joint 145. The hand-rotating mechanism 146 includes a spindle 1462 having a central axis extending in the Y-axis directions perpendicular to the Z-axis directions in Fig. 1. The spindle 1462 is rotatably supported in the housing 1463. For example, the housing 1463 accommodates therein a reversing motor (not shown) for rotating the spindle 1462 about its central axis.

[0031] The spindle 1462 has a distal end portion protruding from the housing 1463, and the robot hand 140 has a proximal end mounted on a holder disposed at the protruding distal end portion of the spindle 1462. When the unillustrated reversing motor is energized, the spindle 1462 is rotated by a predetermined angle about its central axis, which rotates the robot hand 140 connected to the spindle 1462 through the holder to reverse the suction surface 1404 of the robot hand 140, that is, to reverse the suction surface 1404 of the robot hand 140 from top to bottom or vice versa.

[0032] For example, the robot hand 140 has a plate shape for holding a workpiece 80 via suction and, as a whole, has a substantially U-shaped profile when viewed from above. The robot hand 140 includes a base 1406 formed as a flat rectangular plate mounted on the support, and a suction member 1400 formed integrally with the base 1406. The suction member 1400 has a U-shaped opening defined therein. Note that the robot hand 140 according to the present embodiment is not limited to the illustrated shape, but may, as a whole, have a substantially rice grain shape when viewed from above.

[0033] For example, the robot hand 140 has a Fig. 1 serves as a suction surface 1404 for holding a workpiece 80 thereon via suction. Note that the robot hand 140 has a lower surface opposite the suction surface 1404, which may also be a suction surface. The suction surface 1404 has been machined to a smooth surface and may have chamfered edges to protect against damage that may be inflicted upon contact with the workpiece 80.

[0034] A plurality of suction holes open in the suction surface 1404. The suction holes include, for example, three or four suction holes opened in each of five regions arranged at substantially equally spaced intervals along an outer peripheral portion of the suction surface 1404. However, the suction holes are not limited to this number and location in accordance with the present embodiment. The suction holes may have respective elastically deformable rubber suction cups or the like disposed therein.

[0035] Resin tubes are kept in fluid communication with the respective suction ports via couplings or similar devices. The resin tubes are sufficiently flexible to allow the robot hand 140 to rotate and move as desired.

[0036] The resin tubes are connected to a suction source, such as a vacuum generator or an ejection mechanism.

[0037] The intermediate storage table 11 is arranged within the movable range of the robot 14. The intermediate storage table 11 is combined with a positioning unit 119.

[0038] The temporary storage table 11 has, for example, a circular shape smaller in diameter than the workpieces 80 and has a flat upper surface serving as a temporary storage surface for temporarily placing a workpiece 80 thereon. The positioning unit 119 includes a plurality of, for example, six, positioning pins arranged in an annular pattern with equally spaced intervals around the temporary storage table 11. The positioning pins are movable radially inward toward the temporary storage table 11 and radially outward away from the temporary storage table 11. A workpiece 80 temporarily placed on the temporary storage table is positioned or centered at a predetermined position on the temporary storage table 11 when the positioning pins of the positioning unit 119 are moved radially into contact with the outer peripheral edge of the workpiece 80.

[0039] A clipboard rotation mechanism 118, including an electric motor 1181, a spindle 1182, etc., is connected to a lower surface of the clipboard table 11. When the electric motor 1181 is energized, the clipboard table 11 is rotated by the spindle 1182, whose central axis extends in the Z-axis direction. The electric motor 1181 is, for example, a servo motor associated with an encoder 1183 electrically connected to the control unit 9, which also functions as a servo amplifier. When the control unit 9 supplies an actuation signal to the electric motor 1181 from an output interface thereof, the electric motor 1181 is energized, causing the spindle 1182 to rotate about its central axis.The encoder 1883 detects a rotational speed of the electric motor 1181 and consequently of the spindle 1182 and outputs the detected rotational speed as an encoder signal to an input interface of the control unit 9. When the control unit 9 receives the encoder signal representing the rotational speed detected by the encoder 1183, the control unit 9 detects a sequence of rotation angles of the intermediate storage table 11.

[0040] A loading arm 131 including a suction pad or the like for holding a workpiece 80 is angularly movably disposed at a position adjacent to the intermediate storage table 11. The loading arm 131 holds a workpiece 80 that has been centered on the intermediate storage table 11 and feeds the workpiece 80 to the chuck table 30 located at a loading position in the machining area 101. An unloading arm 132 including a suction pad or the like for holding a machined workpiece 80 is angularly movably disposed adjacent to the loading arm 131.

[0041] A workpiece-by-workpiece cleaning unit 12 for cleaning a machined workpiece 80 fed by the unloading arm 132 is arranged in the movable range of the unloading arm 132. The cleaning unit 12 includes the spin table 120, which has a smaller diameter than the workpieces 80, and a cleaning nozzle 121 angularly movable above a workpiece 80 held on the spin table 120. While the workpiece 80 is held on and rotated by the spin table 120, the cleaning nozzle 121 ejects a cleaning fluid toward the back surface 802 of the workpiece 80 to clean the back surface 802.

[0042] A spin table rotation mechanism 126, including an electric motor 123, a spindle 124, etc., is connected to a lower surface of the spin table 120 for rotating the spin table 120 about its central axis extending in the Z-axis direction. The electric motor 123 is, for example, a servo motor associated with an encoder 125, which is electrically connected to the control unit 9, which also functions as a servo amplifier. When the control unit 9 outputs an actuation signal to the electric motor 123 from the output interface, the electric motor 123 is energized, rotating the spindle 124 about its central axis. The encoder 125 detects a rotation speed of the electric motor 123 and thus of the spindle 124 and outputs the detected rotation speed as an encoder signal to the input interface of the control unit 9.When the control unit 9 receives the encoder signal representing the rotation speed detected by the encoder 125, the control unit 9 detects a sequence of rotation angles of the spinning table 120.

[0043] An image pickup unit 127 is arranged above the spin table 120. The image pickup unit 127 includes a light application unit (not shown) for applying light to the back surface 802, i.e., the target surface to be ground, of a workpiece 80 held on the spin table 120, an optical system such as lenses for capturing light reflected from the workpiece 80, and an unillustrated camera such as an image pickup device for outputting an object image focused by the optical system.

[0044] In accordance with the present embodiment, the Fig. The chuck table 30 illustrated in FIG. 1 includes a circular suction member 300 made of a porous material or the like for attracting a workpiece 80 thereto via suction, and a frame 301 supporting the suction member 300. The suction member 300 is held in fluid communication with a suction source (not illustrated), such as a vacuum generator. When the suction source is actuated, it generates a negative pressure that transmits a suction force to a holding surface 302 provided as an exposed upper surface of the suction member 300, enabling the chuck table 30 to hold the workpiece 80 to the holding surface 302 via suction. For example, the holding surface 302 has a shape identical to the shape of the workpiece 80, which has the mark 805 as the orientation plane representing the crystal orientation of the workpiece 80.In other words, the circular suction element 300 has an outer peripheral portion partially removed in tangential directions, leaving an arcuate recess with a flat edge. The arcuate recess with the flat edge in the suction element 300 is also referred to as the "alignment plane alignment part." The alignment plane alignment part is used to align it with the mark 805 of a workpiece 80 when the workpiece 80 is placed on the chuck table 30.

[0045] The clamping table 30 is surrounded at its periphery by a cover 39. The clamping table 30 is reciprocally movable on the base 10 in the Y-axis direction by a table movement mechanism 17 arranged in the base 10 under the cover 39 and a bellows cover 390 coupled to the cover 39. The clamping table 30 is also rotatable about a rotation axis extending in the Z-axis direction by a clamping table rotation mechanism 36.

[0046] The table moving mechanism 17 includes a ball screw 170 having a central axis extending in the Y-axis direction, a pair of guide rails 171 extending parallel to the ball screw 170 and disposed on either side of the ball screw 170, an electric motor 172 coupled to one end of the ball screw 170 for rotating the ball screw 170 about its central axis, and a movable platen 173 having an unillustrated inner nut threadedly engaged with the ball screw 170 and a pair of side portions held in slidable contact with the guide rails 171. The chuck table 30 is mounted on the movable platen 173 with a table base 35 interposed therebetween.When the electric motor 172 is energized, it rotates the ball screw 170 about its central axis, causing the nut to move the movable platen 173 linearly in one of the Y-axis directions while being guided along the guide rails 171, which moves the chuck table 30 mounted on the movable platen 173 via the table base 35 in the same Y-axis direction.

[0047] The clamping table 30 is removably secured to the table base 35. The clamping table rotation mechanism 36 includes an electric motor 360, a spindle 361, etc., and is connected to a lower surface of the table base 35. The electric motor 360 is, for example, a servo motor associated with an encoder 362, which is electrically connected to the control unit 9, which also functions as a servo amplifier. When the control unit 9 supplies an actuation signal to the electric motor 360 from the output interface, the electric motor 360 is energized, rotating the spindle 361 about its central axis. The encoder 362 detects a rotation speed of the electric motor 360 and, consequently, the spindle 361, and outputs the detected rotation speed as an encoder signal to the input interface of the control unit 9.When the control unit 9 receives the encoder signal representing the rotational speed detected by the encoder 362, the control unit 9 detects a sequence of rotation angles of the intermediate storage table 11 and the orientation or position of the arcuate recess with the flat edge in the suction element 300, which corresponds to the mark 805 of the workpiece 80 on the holding surface 302 of the clamping table 30.

[0048] A column 18 is positioned in the +Y direction at the rear of the machining area 101. The column 18 supports a grinding feed mechanism 19 on a front surface facing the -Y direction. The grinding feed mechanism 19 moves, i.e., feeds, the machining unit 16 and the clamping table 30 relative to each other in the Z-axis directions perpendicular to the support surface 302 for grinding.The grinding feed mechanism 19 includes a ball screw 190 having a central axis extending in the Z-axis directions, a pair of guide rails 191 extending parallel to the ball screw 190 and arranged one on each side of the ball screw 190, an electric motor 192 coupled to an upper end of the ball screw 190 for rotating the ball screw 190 about its central axis, a vertically movable platen 193 having an unillustrated inner nut threadedly engaged with the ball screw 190 and a pair of side portions held in slidable contact with the guide rails 191, and a holder 194 coupled to the vertically movable platen 193 and holding the machining unit 16.When the electric motor 192 is energized, it rotates the ball screw 190 about its central axis, which causes the inner nut to move the vertically movable plate 193 in one of the Z-axis directions while moving it along the guide rails 191, which moves the machining unit 16 held by the holder 194 in the same Z-axis direction, that is, feeds it for machining.

[0049] The machining unit 16, which grinds a workpiece 80 held on the chuck table 30, includes a shaft or rotation axis 160 having a central axis extending in the Z-axis direction, a housing 161 in which the rotation axis 160 is rotatably supported, an electric motor 162 for rotating the rotation axis 160 about its central axis, an annular holder 163 connected to a lower end of the rotation axis 160, and a grinding wheel 164 detachably mounted on a lower surface of the annular holder 163.

[0050] The grinding wheel 164 includes a wheel base and a plurality of grinding stones, each having a substantially rectangular cuboid shape and mounted in an annular array on a lower surface of the wheel base. The grinding stones are made, for example, of abrasive grains strongly held together by a binder or the like.

[0051] The rotation axis 160 has a fluid channel (not shown) defined axially therethrough in the Z-axis direction as a passage for a grinding fluid. The fluid channel also extends through the annular support 163 and is open at the lower surface of the wheel base for discharging the grinding fluid from a grinding fluid source (not shown) toward the grinding stones.

[0052] A contact thickness measuring unit 38 for measuring the thickness of a workpiece 80 being ground during contact therewith is arranged at a position near the grinding wheel 164, which has been lowered to a height or vertical position at which the grinding wheel 164 grinds the workpiece 80. The thickness measuring unit 38 includes, for example, a pair of thickness gauges or height gauges, namely, a first thickness gauge, i.e., a first height gauge 381, for measuring the vertical position of the holding surface 302 of the chuck table 30 and a second thickness gauge, i.e., a second height gauge, 382, ​​for measuring the vertical position of the back surface 802 of the workpiece 80 held on the chuck table 30.

[0053] The first thickness gauge 381 and the second thickness gauge 382 each have a contact portion that is vertically movable in contact with a surface to be measured. Specifically, the first thickness gauge 381 and the second thickness gauge 382 are vertically movably supported and can be held against the respective surfaces to be measured under an appropriate force. The first thickness gauge 381 measures or detects the vertical position of the support surface 302 serving as a reference surface, whereas the second thickness gauge 382 measures or detects the vertical position of the back side 802 of the workpiece 80 to be ground, which faces upward. The thickness measuring unit 38 calculates the difference between the detected vertical positions, thereby continuously measuring the thickness of the workpiece 80 while the workpiece 80 is being ground.

[0054] It should be noted that the thickness measuring unit 38 may be a non-contact thickness measuring unit.

[0055] The machining device 1 according to the present invention includes a determination section 90 for determining whether a tool 80 that has been ground is a workpiece that has been properly machined or a workpiece that has not been properly machined. According to the present embodiment, the determination section 90 belongs to the control unit 9.

[0056] The determination section 90 includes a plurality of, for example, two, determination sections capable of determining, in accordance with respective different determination criteria, whether a workpiece 80 that has been ground is a workpiece that has been properly machined, or a workpiece that has not been properly machined. Specifically, according to the present embodiment, the determination section 90 includes a first determination section 901 for determining whether a workpiece 80 is a workpiece that has been properly machined, a workpiece that has not been properly machined, or a workpiece whose thickness before grinding, i.e., a loading thickness, is abnormal and is not to be ground, based on the thickness of the workpiece 80 measured by the thickness measuring unit 38, and a second determination section 902 for determining whether a workpiece 80 is cracked.chipped on its outer circumference or burned on its surface or not, via an image taken by the image pickup unit 127 of the back 802 of the workpiece 80 that has been cleaned on the spin table 120, and for determining that the workpiece 80 is a workpiece that has been properly machined if the workpiece 80 is not cracked, chipped, or burned, and that the workpiece 80 is a workpiece that has not been properly machined if the workpiece 80 is cracked, chipped, or burned.

[0057] When the determination section 90 has determined that the workpiece 80 has been properly machined, the control unit 9 in accordance with the present embodiment executes a control operation for aligning the mark 805 in a predetermined direction 99, hereinafter referred to as “proper machining direction 99”, shown in Fig. 4, and stores the workpiece 80 that has been machined in the second cassette 22, and when the determination section 90 has determined that the workpiece 80 has not been properly machined, the control unit 9 executes a control operation to align the mark 805 in a direction deviating from the proper machining direction 99 and stores the workpiece 80 that has been machined or that has not yet been machined in the second cassette 22.

[0058] According to the present embodiment, the determination section 90 includes the first determination section 901 and the second determination section 902, and in a case where the first determination section 901 and / or the second determination section 902, that is, one or more of the plurality of determination sections, determines that the workpiece 80 has not been properly machined, the control unit 9 executes the control operation of aligning the mark 805 in the direction set in the determination section that determined that the workpiece 80 has not been properly machined, which is different from the proper machining direction 99, and stores the workpiece 80 in the second cassette 22.For example, the deviated direction preset in the first determination section 901 and applied in a case where the workpiece 80 has not been properly machined will hereinafter be referred to as “machining thickness anomaly direction 98” (see . Fig. 5). The deviating direction preset in the second determination section 902 and applied in a case where the workpiece 80 has not been properly machined is hereinafter referred to as “machining crack anomaly direction, etc. 97” (see Fig. 6). The machining thickness anomaly direction 98 and the machining crack anomaly direction 97 are preset to be inconsistent.

[0059] It is hereby established that an operation of Fig. 1 for grinding a workpiece 80 held on the clamping table 30 will be described in detail. (Grinding the first workpiece 80)

[0060] Under the control of the control unit 9, for example, a first workpiece 80 is unloaded from the first cassette 21. In particular, the vertical hand movement mechanism 144 moves the robot hand 140 of the robot 14 in the vertical direction to position the robot hand 140 at a height or vertical position aligned with the tray 226, such as the lowest tray 226 in Fig. 2, where the first workpiece 80 is stored in the first cassette 21.

[0061] In the first cassette 21, for example, the front side 801 of the workpiece 80 is facing downward and the back side 802 is facing upward. Then, the suction surface 1404 of the robot hand 140 is set to an upward-facing state, that is, a state directed in the +Z direction.

[0062] For example, the robot hand 140 is rotated to enter the first cassette 21 through the opening 210 of the first cassette 21 to a predetermined position therein, and is positioned at the predetermined position in a horizontal plane where the center of the robot hand 140 and the center of the workpiece 80 are substantially aligned. Then, the robot hand 140 is lifted to bring its suction surface 1404 into contact with the end face 801 of the workpiece 80, causing the suction surface 1404 to hold the workpiece 80 by suction. The robot hand 140 ceases to be lifted when the workpiece 80 lifted by the robot hand 140 is slightly spaced from the tray 226 at its outer peripheral edge.

[0063] The robot hand 140, which has been holding the workpiece 80 under suction, is moved in the +Y direction and unloads the workpiece 80 from the first cassette 21. It should be noted that the robot hand 140 can bring the suction surface 1404 against the workpiece 80 from above to hold the workpiece 80 under suction.

[0064] The Fig. 1 then moves the workpiece 80 over the intermediate storage table 11 and places the workpiece 80 on the intermediate storage table 11 with the end face 801 facing downward. In particular, the robot hand 140 is lowered to place the workpiece 80 on the intermediate storage table so that the intermediate storage table 11 enters the U-shaped opening in the suction element 1400 of the robot hand 140.

[0065] Then, the positioning pins of the positioning unit 119 are moved radially inward while being held in a circular row and press the outer peripheral edge of the workpiece 80 in a targeted manner, which corrects the position of the workpiece 80. For example, the Fig. 6 illustrates six positioning pins starting to move when they all touch the outer peripheral edge of the workpiece 80. As a result, the center of the workpiece 80 is aligned with the center of the intermediate table 11, so that the control unit 9 can detect the center position of the first workpiece 80. Thereafter, the workpiece 80 is held on the intermediate table 11 by suction.

[0066] Since the workpiece 80 has the arcuate recess as the mark 805, which represents the alignment plane, one of the Fig. 1 illustrates six positioning pins positioned at the mark 805, for example, when centering the workpiece 80, moving one of the six positioning pins radially inward by a greater distance than the other positioning pins. Consequently, the different distance by which one of the six positioning pins is moved radially inward allows the control unit 9 to detect the position of the mark 805 of the workpiece 80 centered on the intermediate table 11. Then, for example, the intermediate table 11, which holds the workpiece 80 by suction, is rotated by a certain angle under the control of the control unit 9 to align the mark 805 of the workpiece 80 in a predetermined direction.In accordance with an alternative approach, for example, an image acquisition unit may be positioned above the intermediate storage table 11, and the control unit 9 may analyze an image of the workpiece 80 acquired by the image acquisition unit and recognize the center point and the mark 805 of the workpiece 80 on the intermediate storage table 11 from the image.

[0067] Next, the loading arm 131 holds and moves the workpiece 80 which has been centered on the intermediate storage table 11 and whose mark has been placed at a predetermined circumferential position on the clamping table 30.

[0068] As described above, the holding surface 302 of the chuck table 30 includes the alignment plane alignment part for aligning it with the mark 805 of the workpiece 80 when the workpiece 80 is placed on the chuck table 30. The chuck table 30 is rotated to position the alignment plane alignment part in alignment with the mark 805 of the workpiece 80 on the chuck table 30 in terms of its angle. Specifically, the position of the mark 805 of the workpiece 80 at the time the loading arm 131 holds the workpiece 80 has already been detected by the control unit 9 when the loading arm 131 feeds from the intermediate table 11 to the chuck table 30.The control unit 9 controls the clamp table rotation mechanism 36 to rotate the clamp table 30 by a predetermined angle to align the alignment plane alignment part of the clamp table 30 with the mark 805 of the workpiece 80, which is fed from the intermediate table 11 to the clamp table 30 by the loading arm 131. The workpiece 80 is then placed on the support surface 302 of the clamp table 30 with the back surface 802 facing upward, so that the center of the clamp table 30 and the center of the workpiece 80 are substantially aligned with each other.

[0069] The suction force generated when the suction source fluidly connected to the suction element 300 is actuated is transmitted to the holding surface 302 of the chuck table 30, enabling the chuck table 30 to hold the workpiece 80 to the holding surface 302 via suction. Furthermore, the circumferential position of the mark 805 of the workpiece 80 held to the holding surface 302 via suction has been detected by the control unit 9. Since the control unit 9 controls the chuck table rotation mechanism 36, the control unit 9 continues to detect the circumferential position of the mark 805 of the workpiece 80 at any time after grinding of the workpiece 80 has begun or after the workpiece has been ground.

[0070] After the chuck table 30 has suction-held the workpiece 80 onto the holding surface 302, the table moving mechanism 17 moves the chuck table 30 in the +Y direction. The chuck table 30, with the workpiece 80 held thereon, is moved until it reaches a position where the rotation center of the grinding wheel 164 of the machining unit 16 is horizontally offset by a predetermined distance from the rotation center of the workpiece 80, and the track to be followed by the grinding stones as they rotate passes through the rotation center of the workpiece 80.

[0071] For example, before starting a grinding process for grinding the workpiece 80, the thickness measuring unit 38 measures the loading thickness of the workpiece 80. The loading thickness refers to the thickness of the workpiece 80 at the time the workpiece 80 is loaded into the machining area 101, that is, before the workpiece 80 is machined. Information of the loading thickness of the workpiece 80 measured by the thickness measuring unit 38 is sent to the first determination section 901 of the determination section 90 of the control unit 9. The control unit 9 includes a storage medium that includes a preset allowable range for the loading thickness of the workpiece 80. The first determination section 901 determines, through comparison, whether or not the loading thickness of the first workpiece 80 falls within the allowable range for the loading thickness.

[0072] For example, the first determination section 901 determines that the loading thickness of the first workpiece 80 falls within the allowable loading thickness range. In this case, the grinding process for grinding the workpiece 80 is started.

[0073] The machining unit 16 is fed in the -Z direction by the grinding feed mechanism 19, which brings the rotating grindstones into contact with the back surface 802 of the workpiece 80 held on the chuck table 30, thereby grinding the back surface 802 of the workpiece 80. As the chuck table rotating mechanism 36 rotates the chuck table 30 at a predetermined rotation speed, the workpiece 80 on the holding surface 302 rotates therewith, causing the grindstones to grind the back surface 802 of the workpiece 80 as a whole. While the workpiece 80 is being ground, the grinding fluid is supplied through the fluid channel to a contact area where the grindstones and the back surface 802 of the workpiece 80 contact each other, cooling and cleaning the contact area.

[0074] During the grinding process, the thickness measuring unit 38 continuously measures the thickness of the workpiece 80 and sends information of the measured thickness to the first determination section 901 of the determination section 90 of the control unit 9. For example, the storage medium of the control unit 9 also stores a finished thickness of the workpiece 80 and an allowable range of several ±µm, such as the finished thickness. The first determination section 901 continuously monitors the measurements from the thickness measuring unit 38 to determine whether or not the thickness of the first workpiece 80 falls within the finished thickness and the allowable range of several ±µm while being ground.

[0075] For example, the thickness measuring unit 38 measures the thickness of the workpiece 80, and the first determination section 901 monitors the thickness of the workpiece 80. The machining unit 16 is lifted and spaced from the workpiece 80 that has been properly ground to the finished thickness after the chuck table 30, with the workpiece 80 held thereon under suction, is rotated through a predetermined angle under the control of the control unit 9 to align the mark 805 of the workpiece 80 in a predetermined direction. Then, the table moving mechanism 17 moves the chuck table 30 in the Y direction to a position near the unloading arm 132.

[0076] With the marker 805 positioned at a predetermined circumferential position, the unloading arm 132 next holds and guides the workpiece 80 from the chuck table 30 to the spin table 120. The workpiece 80 is placed on the spin table 120 with the back surface 802 facing upward, the diameter of which is smaller than that of the workpiece 80, and the workpiece 80 is then held to the spin table 120 by suction. The center of the workpiece 80 and the center of the spin table 120 are substantially aligned with each other. Then, the cleaning nozzle 121 is reciprocated over the workpiece 80 at a predetermined angle while ejecting the cleaning fluid toward the back surface 802 of the workpiece 80.At the same time, the spin table rotation mechanism 126 rotates the spin table 120 at a predetermined rotation speed, allowing the cleaning fluid to be supplied to the entire back surface 802 of the workpiece 80, thereby cleaning the back surface 802.

[0077] The encoder 125 associated with the electric motor 123 of the spin table rotation mechanism 126 outputs an encoder signal to the control unit 9 while the spin table 120 rotates. The control unit 9 continuously detects the angular position of the mark 805 of the rotating workpiece 80 based on the received encoder signal.

[0078] After the workpiece 80 has been cleaned for a predetermined period of time, the spin table 120 stops rotating, and the cleaning nozzle 121 applies, for example, air to the workpiece 80, which dries the workpiece 80. Then, the image pickup unit 127 captures an image of the back surface 802 of the workpiece 80. The captured image is sent from the image pickup unit 127 to the second determination section 902 of the determination section 90 of the control unit 9. The second determination section 902 analyzes the captured image while performing a binarization process, an edge processing process, etc. on the captured image on a virtual output screen, and determines from the captured image whether or not the workpiece 80 is cracked, chipped on its outer periphery, wavy, or burned on its surface.For example, the second determination section 902 determines that the first workpiece 80 that has been ground is not cracked, chipped, wavy, or burned.

[0079] Consequently, the first determination section 901 has determined that the first workpiece 80 has been properly ground to the finished thickness, and the second determination section 902 has also determined that it is free from grinding failure, that is, it is not cracked, chipped, wavy, or burned. In a case where the determination section 90 thus determines that the workpiece 80 has been properly machined, the control unit 9 executes the control process for aligning the mark 805 in the proper machining direction 99 (see Fig. 4) and stores the properly machined workpiece 80 in the second cassette 22.

[0080] In particular, the Fig. 1, the robot hand 140 of the robot 14 is moved by the vertical hand movement mechanism 144 in the Z-axis direction to a predetermined vertical position where the suction surface 1404 facing upward can hold the end face 801 of the workpiece 80 on the spin table 120 by suction. Furthermore, the robot hand 140 is rotated by the horizontal hand movement mechanism 142 until the U-shaped opening in the suction element 1400 of the robot hand 140 is positioned directly opposite the spin table 120 in the X-axis direction. In other words, the robot hand 140, as shown in Fig. 3 illustrates its distal end portion aligned in the -X direction.

[0081] The spinning table 120 with the workpiece 80 held thereon under suction is moved under the control of the Fig. 1 illustrated control unit 9 is rotated by a predetermined angle to mark the mark 805 of the workpiece 80, as shown in Fig. 3 illustrates the U-shaped opening in the suction element 1400 of the robot hand 140 being aligned directly opposite in the +X direction.

[0082] The horizontal hand movement mechanism 142 moves the robot hand 140 linearly in the -X direction to cause the sling table 120 to enter the U-shaped opening in the suction element 1400. The robot hand 140 is then placed, for example, in a horizontal plane at a predetermined position where the center of the robot hand 140 and the center of the workpiece 80 are substantially aligned. The robot hand 140 is then raised to bring the suction surface 1404 into contact with the end face 801 of the workpiece 80, whereupon the suction surface 1404 holds the workpiece 80 under suction. The mark 805 of the workpiece 80 is aligned toward the base 1406 of the robot hand 140.

[0083] Then, the robot hand 140, which holds the workpiece 80 by suction, is rotated by the horizontal hand movement mechanism 142 under the control of the control unit 9 until the robot hand 140 is positioned directly opposite the front opening 220 of the second cassette 22 in the Y-axis direction. In other words, the mark 805 of the workpiece 80 held by the robot hand 140 by suction is aligned in the +Y direction.

[0084] In addition, the robot hand 140 is moved to the vertical position of the shelf 226, for example, the lowest shelf 226 in Fig. 2, where the workpiece 80 is to be stored in the second cassette 22. The robot hand 140 is moved linearly in the -Y direction to a predetermined position in the second cassette 22. The robot hand 140 then releases the workpiece 80, which is placed with the back 802 facing upward on the tray 226 in the second cassette 22. The robot hand 140, positioned under the workpiece 80, is then withdrawn from the second cassette 22.

[0085] Consequently, the first workpiece 80, as shown in Fig. 4, on the tray 226 with the mark 805 aligned in the proper machining direction 99, that is, aligned in the +Y direction towards the front opening 220 of the second cassette 22, stored in the second cassette 22. (Grinding the second workpiece 80)

[0086] For example, while the first workpiece 80 is being ground by the grinding wheel 164 as described above, the Fig. 1, robot 14 next removes a second workpiece 80 to be ground from the first cassette 21 in the same manner as when unloading the first workpiece 80. Then, the Fig. 1, robot 14 illustrated the second workpiece 80 over the intermediate storage table 11. As with the first workpiece 80, the second workpiece 80 is centered on the intermediate storage table 11, and the circumferential position of the mark 805 of the second workpiece 80 is detected by the control unit 9.

[0087] After the ground first workpiece 80 is unloaded from the chuck table 30 by the unloading arm 132, leaving the chuck table 30 unoccupied, the loading arm 131 holds and moves the second workpiece 80, which has been centered on the intermediate table 11 and whose mark 805 has been brought to the circumferential position above the chuck table 30. The second workpiece 80 is then held on the chuck table 30 by suction while the center of the second workpiece 80 and the center of the chuck table 30 are aligned with each other, and while the alignment plane alignment part of the chuck table 30 and the mark 805 of the second workpiece 80 are also aligned with each other.

[0088] After the clamping table 30 has held the workpiece 80 thereto by suction, the table movement mechanism 17 moves the clamping table 30 in the +Y direction. The workpiece 80 and the grinding wheel 164 of the machining unit 16 are then positioned relative to each other.

[0089] Before starting a grinding operation for grinding the second workpiece 80, the thickness measuring unit 38 measures the loading thickness of the workpiece 80. Information of the loading thickness is sent to the first determination section 901. The first determination section 901 determines, through comparison, whether the loading thickness of the second workpiece 80 falls within the allowable range for the loading thickness. For example, the first determination section 901 determines that the loading thickness of the second workpiece 80 does not fall within the allowable range.It should be noted that the loading thickness of the second workpiece 80 does not fall within the allowable range in a case where the loading thickness of the second workpiece 80 is larger than the allowable range for the loading thickness, that is, in a case where the workpiece 80 is too thick, or in a case where the loading thickness of the second workpiece 80 is smaller than the allowable range for the loading thickness, that is, in a case where the workpiece 80 is too thin.

[0090] In this case, the first determination section 901 controls a speaker of the machining device 1 to output a warning sound, or controls a display device such as a display monitor or a touch panel of the machining device 1 to display an error message, notifying the worker operating the machining device 1 of the determined result that the machining device 1 will not perform a grinding operation on the second workpiece because the loading thickness of the second workpiece 80 is larger than the allowable range for the loading thickness, that is, the workpiece 80 is too thick, or the loading thickness of the second workpiece 80 is smaller than the allowable range for the loading thickness, that is, the workpiece is too thin.

[0091] Furthermore, the second workpiece 80 is not ground but stored in the second cassette 22 under the control of the control unit 9. Specifically, the table moving mechanism 17 moves the chuck table 30 to a position near the unloading arm 132. The unloading arm 132 then holds and moves the workpiece 80, whose mark 805 has been placed from the chuck table 30 to the spin table 120 at the circumferential position.

[0092] The robot hand 140 is brought to a predetermined height or vertical position to hold the front side 801 of the workpiece 80 with the back side 802 facing upward on the spin table 120 by suction. Furthermore, the robot hand 140 is rotated by the horizontal hand movement mechanism 142 until the U-shaped opening in the suction element 1400 of the robot hand 140 is aligned in the -X direction and positioned directly opposite the spin table 120 in the X-axis directions.

[0093] The spinning table 120 with the workpiece 80 held thereon under suction is rotated by a predetermined angle under the control of the control unit 9 until the mark 805 of the workpiece 80 is aligned clockwise from the +Z direction at an angle with respect to the U-shaped opening in the robot hand 140 of, for example, 45°.

[0094] The Fig. The robot hand 140 illustrated in Figure 1 is moved linearly in the -X direction by the horizontal hand movement mechanism 142 and then holds the workpiece 80 under suction so that the center of the robot hand 140 and the center of the workpiece 80 are substantially aligned. The mark 805 of the workpiece 80 has been angularly spaced 45° clockwise from the +Z direction relative to the base 1406 of the robot hand 140.

[0095] The robot hand 140 rotated by the horizontal hand movement mechanism 142 under the control of the control unit 9 is positioned in the Y-axis directions directly opposite to the front opening 220 of the second cassette 22. In addition, the robot hand 140 is moved to the vertical position of the tray 226, for example, the next tray 226 in Fig. 2, which is higher than the lowest shelf 226, where the workpiece 80 is to be stored in the second cassette 22, is raised or lowered. The robot hand 140 is moved linearly in the -Y direction to a predetermined position in the second cassette 22. Then, the robot hand 140 releases the workpiece 80, which is placed in the second cassette 22 with the back 802 facing upward on the shelf 226. Thereafter, the robot hand 140, which is positioned below the workpiece 80, is retracted from the second cassette 22.

[0096] As in Fig. 5, the second workpiece 80 is therefore stored on the tray 226 in the second cassette 22 with the mark 805 aligned in the machining thickness anomaly direction 98, that is, viewed from above, aligned in the direction 98 spaced 45° angularly clockwise with respect to the front opening 220 of the second cassette 22 aligned in the +Y direction. (Grinding the third workpiece 80)

[0097] For example, while the thickness of the second workpiece 80 is being measured as described above, the Fig. 1, robot 14 illustrates unloading a third workpiece 80 to be ground next from the cassette 21 in the same manner as the first workpiece 80 was unloaded.

[0098] Then the Fig. 1, robot 14 illustrated the third workpiece 80 via the intermediate storage table 11. As with the first workpiece 80, the third workpiece 80 is centered on the intermediate storage table 11, and the circumferential position of the mark 805 of the third workpiece 80 is detected by the control unit 9.

[0099] After the second workpiece 80 is unloaded from the chuck table 30 by the unloading arm 132, leaving the chuck table 30 unoccupied, the loading arm 131 holds and moves the third workpiece 80, which has been centered on the intermediate table 11 and whose mark 805 has been brought to the circumferential position above the chuck table 30. The third workpiece 80 is then held on the chuck table 30 by suction while the center of the third workpiece 80 and the center of the chuck table 30 are aligned with each other, and while the alignment plane alignment part of the chuck table 30 and the mark 805 of the third workpiece 80 are also aligned with each other.

[0100] After the chuck table 30 holds the workpiece 80 thereto by suction, the table moving mechanism 17 moves the chuck table 30 in the +Y direction, and the workpiece 80 and the grinding wheel 164 of the machining unit 16 are then positioned with respect to each other. Furthermore, before starting a grinding operation for grinding the third workpiece 80, the thickness measuring unit 38 measures, for example, the loading thickness of the workpiece 80. The first determination section 901, having received information of the measured loading thickness, determines that the loading thickness of the third workpiece 80 falls within the allowable range. In this case, the grinding operation for grinding the third workpiece 80 is started.

[0101] During the grinding process for grinding the third workpiece 80, which is performed in the same manner as the grinding process for grinding the first workpiece 80, the thickness measuring unit 38 continuously measures the thickness of the workpiece 80 and sends information of the measured thickness to the first determination section 901 of the determination section 90. The first determination section 901 continuously monitors the measurements from the thickness measuring unit 38 to determine whether or not the thickness of the third workpiece 80 while being ground falls within the finished thickness and the allowable range of several ±µm.

[0102] For example, although the thickness measuring unit 38 measures the thickness of the workpiece 80 and the first determination section 901 monitors the thickness of the workpiece 80, due to the volume of processing tasks of the control unit 9, a time delay may occur until the measured thickness information of the workpiece 80 obtained by the thickness measuring unit 38 is sent to the first determination section 901. This time delay may delay control of the grinding feed mechanism 19 by the control unit 9, which tends to cause a delay in lifting the processing unit 16 from the workpiece 80 with the grinding feed mechanism 19. As a result, the ground third workpiece 80 may be made thinner than the thickness calculated by subtracting the allowable range from the predetermined finished thickness. It should be noted that the workpiece 80 may also be thinner due to the condition of the grindstones, etc.can be made thinner than the thickness calculated by subtracting the allowable range from the predetermined finished thickness.

[0103] Furthermore, although the thickness measuring unit 38 measures the thickness of the workpiece 80 and the first determination section 901 monitors the thickness of the workpiece 80, the workpiece may not be properly ground in cases where, for example, the back surface 802 of the workpiece 80 has an abnormality such as surface burn, or where the grinding stones of the machining unit are not sharp enough during grinding. In this case, when the machining unit 16 is lifted from the workpiece 80 under the control of the grinding feed mechanism 19 controlled by the control unit 9, the third workpiece 80 that has been ground may be made thicker than the thickness calculated by adding the allowable range to the predetermined finished thickness.

[0104] In this case, the first determination section 901 controls the speaker of the machining device 1 to output a warning sound, or controls the display device such as a touch panel of the machining device 1 to display an error message, notifying the worker of the determined result that the thickness of the third workpiece 80 that has been ground has experienced a thickness deviation.

[0105] For example, the clamping table 30 with the workpiece 80 held thereon under suction is rotated by a predetermined angle under the control of the control unit 9 to align the mark 805 of the ground third workpiece 80 in a predetermined direction. Then, the clamping table 30 is moved in the -Y direction and positioned near the unloading arm 132, which feeds the workpiece 80 from the clamping table 30 to the spinning table 120.

[0106] After the cleaning unit 12 has cleaned and dried the workpiece 80, the image acquisition unit 127 captures an image of the back surface 802 of the workpiece 80. The second determination section 902 determines from the captured image whether the workpiece 80 is cracked, chipped, wavy, or burned on its outer periphery. For example, the second determination section 902 determines that the third workpiece 80, which has been ground, is not cracked, chipped, wavy, or burned.

[0107] The control unit 9 performs a control operation for aligning the mark 805 of the ground third workpiece 80, which the first determination section 901 of the determination section 90 has determined to have an abnormal thickness, in the machining thickness anomaly direction 98 (see Fig. 5) and stores the workpiece 80 in the second cassette 22. Specifically, the control unit 9 performs the same control operation as the above-described control operation for storing the second workpiece 80 in the second cassette 22, which stores the third workpiece 80 on the tray 226 of the second cassette 22 with the mark 805 aligned in the machining thickness anomaly direction 98 of the second cassette 22, that is, in the angularly spaced direction of 45° as viewed clockwise from above with respect to the front opening 220 aligned in the +Y direction. (Grinding the fourth workpiece 80)

[0108] For example, while the third workpiece 80 is being ground by the grinding wheel 164 as described above, the robot 14 unloads a fourth workpiece 80 to be ground next in the same manner as the first workpiece 80 was unloaded from the Fig. 1. The fourth workpiece fed by the robot 14 is then centered on the intermediate storage table 11, like the first workpiece 80, and the circumferential position of the mark 805 is detected by the control unit 9.

[0109] After the third workpiece 80 is unloaded from the chuck table 30 by the unloading arm 132, the fourth workpiece 80, placed with the mark 805 centered in the circumferential position, is moved onto the chuck table 30 by the loading arm 131. The fourth workpiece 80 is then held on the chuck table 30 by suction, while the center of the fourth workpiece 80 is centered with the chuck table 30, and while also aligning the alignment plane alignment part of the chuck table 30 and the mark 805 of the fourth workpiece 80 with each other.

[0110] After the chuck table 30 holds the workpiece 80 thereon by suction, the table moving mechanism 17 positions the workpiece 80 and the grinding wheel 164 of the machining unit 16 relative to each other. Before starting a grinding operation for grinding the fourth workpiece 80, the thickness measuring unit 38 further measures the loading thickness of the workpiece 80. The first determination section 901, having received information of the measured loading thickness, determines that the loading thickness of the fourth workpiece 80 falls within the allowable range.

[0111] During the grinding process for grinding the fourth workpiece 80, which is performed in the same manner as the grinding process for grinding the first workpiece 80, the thickness measuring unit 38 continuously measures the thickness of the workpiece 80 and sends information of the measured thickness to the first determining section 901. The first determining section 901 continuously monitors the measurements from the thickness measuring unit 38 to determine whether or not the thickness of the fourth workpiece 80 while being ground falls within the finished thickness and the allowable range of several ±µm.

[0112] After the machining unit 16 has been left and spaced from the workpiece 80 that has been properly ground to the finished thickness, while the thickness measuring unit 38 measures the thickness of the workpiece 80 and the first determination section 901 monitors the thickness of the workpiece 80, the chuck table 30, which has held the workpiece 80 thereon by suction, is rotated by a predetermined angle under the control of the control unit 9 to align the mark 805 of the workpiece 80 in a predetermined direction. Then, the table moving mechanism 17 moves the chuck table 30 in the -Y direction to a position near the unloading arm 132.

[0113] Then, the unloading arm 132 holds and moves the workpiece 80, whose mark 805 has been placed at a predetermined circumferential position, from the chuck table 30 to the spin table 120. After the cleaning unit 12 has cleaned and dried the fourth workpiece, the image pickup unit 127 captures an image of the back surface 802 of the workpiece 80. The second determination section 902 determines from the captured image whether or not the workpiece 80 is cracked, chipped on its outer circumference, wavy, or burned on its surface. For example, the second determination section 902 determines that the fourth workpiece 80 has a crack 808 (see Fig. 6). In this case, the second determination section 902 emits an alarm sound or displays an error message, notifying the worker of the determined result that the ground fourth workpiece 80 has a machining abnormality.

[0114] Then, the control unit 9 performs a control operation for aligning the mark 805 of the ground fourth workpiece 80 in the direction of the machining crack anomaly direction 97 (see Fig. 6) which has been determined by the second determining section 902 to have the crack 808, and stores the fourth workpiece 80 in the second cassette 22.

[0115] Specifically, the robot hand 140 is raised to a predetermined height or vertical position to hold the downward-facing end face 801 of the workpiece 80 to the spin table 120 by suction. Furthermore, the robot hand 140 is rotated until the U-shaped opening of the robot hand 140 is aligned in the -X direction and positioned directly opposite the spin table 120 in the X-axis directions.

[0116] The spin table 120 is rotated, for example, by a predetermined angle under the control of the control unit 9 until the mark 805 of the workpiece 80 is aligned at an angle of 45° counterclockwise from the +Z direction with respect to the U-shaped opening in the robot hand 150.

[0117] The horizontal hand movement mechanism 142 moves the robot hand 140 linearly in the -X direction until the center of the robot hand 140 and the center of the workpiece 80 are substantially aligned, after which the robot hand 140 holds the workpiece 80 under suction. The mark 805 of the workpiece 80 is oriented counterclockwise from the +Z direction with respect to the base 1406 of the robot hand 140 at an angle of 45°.

[0118] Then, the robot hand 140 is rotated by the horizontal hand movement mechanism 142 under the control of the control unit 9 until the robot hand 140 is positioned in the Y-axis direction directly opposite the front opening 220 of the second cassette 22. Furthermore, the robot hand 140 is raised or lowered to the vertical position of the tray 226 where the workpiece 80 is to be stored in the second cassette 22. Furthermore, the robot hand 140 is moved linearly in the Y-direction to a predetermined position in the second cassette 22. Then, the robot hand 140 releases the workpiece 80 placed in the second cassette 22 with the back side 802 facing upward onto the tray 226. After that, the robot hand 140 is withdrawn from the second cassette 22.

[0119] Therefore, the fourth workpiece 80, as shown in Fig. 6, stored on the tray 226 in the second cassette 22 while the mark 805 is oriented in the machining crack anomaly direction etc. 97, that is, in the counterclockwise direction viewed from above angularly spaced by 45° relative to the front opening 220 of the second cassette 22 which is oriented in the +Y direction.

[0120] The machining apparatus 1 in accordance with the present invention comprises the determination section 90 which determines whether a workpiece 80 has been properly machined or not properly machined, and the control unit 9 which executes a control operation for aligning the mark 805 of the workpiece 80 in a predetermined direction, that is, the direction shown in Fig. 4, when the determining section 90 determines that the workpiece 80 has been properly machined, stores the workpiece 80 in the second cassette 22, and carries out, for example, a control operation for aligning the mark 805 of the workpiece 80 in a direction deviating from the proper machining direction 99, that is, the direction shown in Fig. 5 illustrated machining thickness anomaly direction 98 or the one in Fig. 6, when the determining section 90 determines that the workpiece 80 has been improperly machined, it determines the machining crack anomaly direction 97 illustrated in FIG. 6 and stores the workpiece 80 in the second cassette 22. Therefore, the worker can easily determine whether the workpiece 80 has been properly machined, like the first workpiece 80, or improperly machined, like any of the second to fourth workpieces 80, by observing the orientation of the mark 805 of the workpiece 80 stored in the second cassette. For example, the worker can then easily remove only the workpiece 80 that has been improperly machined without laboriously comparing workpiece data on a display screen of the device.Accordingly, after the second cassette 22 has been filled, it is possible for the worker to feed the second cassette 22, from which the workpieces 80 that have not been properly processed have been removed, to a device in a next processing step.

[0121] The machining device 1 in accordance with the present invention includes the thickness measuring unit 38 for measuring the thickness of a workpiece 80, and the determination section 90 determines whether the workpiece 80 has been properly machined or not properly machined based on the thickness of the workpiece 80 measured by the thickness measuring unit 38, so that the control unit 9 can easily perform the control operation for aligning the mark 805 of the workpiece 80 in the predetermined direction 99, that is, the direction shown in Fig. 4, or the control process for aligning the mark 805 of the workpiece 80 in the direction 98 deviating from the proper machining direction 99, that is to say the direction shown in Fig. 5 illustrated machining thickness anomaly direction 98.

[0122] The determination section 90 includes a plurality of determination sections, that is, the first determination section 901 and the second determination section 902 according to the present embodiment, which determine whether the workpiece 80 is a workpiece that has been properly machined or a workpiece that has not been properly machined according to respective different determination criteria. If at least one of the first determination section 901 and the second determination section 902 determines that the workpiece 80 has not been properly machined, the control unit 9 performs the control operation to align the mark 805 in the machining thickness anomaly direction 98 preset by the first determination section 901 that determines that the workpiece 80 has not been properly machined, or in the machining crack anomaly direction, etc.97 preset by the second determining section 902, which determines that the workpiece 80 has been improperly machined because it does not agree with the machining thickness anomaly direction 98, and stores the workpiece in the second cassette 22. The worker can easily know whether the workpiece 80 has been properly machined or improperly machined by observing the orientation of the mark 805 of the workpiece 80 stored in the second cassette 22 and can recognize the type of anomaly of the workpiece 80 that has been improperly machined.

[0123] The machining device 1 according to the present invention is not limited to the above embodiment, but can be implemented in a variety of different ways within the scope of the technical subject matter of the invention. The external profiles, etc., of the components of the machining device 1 illustrated in the accompanying drawings are not limitative, but can be changed and modified to the extent that the advantages of the present invention apply.

[0124] For example, assume that when the above-described fourth workpiece 80 is ground, the first determination section 901 determines that the ground fourth workpiece 80 has a thickness abnormality, and the second determination section 902 further determines that the ground fourth workpiece 80 has a machining abnormality such as the crack 808. In this situation, the control unit 9 may execute a control operation for aligning the mark 805 of the workpiece 80 in a direction defined for a case where both the first determination section 901 and the second determination section 902 determine that the ground workpiece 80 is abnormal and deviates from the thickness specified in Fig. 4 and stores the workpiece 80 in the second cassette 22. In this case, the fourth workpiece 80 is, for example, stored in the second cassette 22 with the marking 805 of the rear plate 225 of the Fig. 1, that is to say with the marking 805 facing the rear side of the second cassette 22.

Claims

[1] Processing device (1) comprising: a chuck table (30) for holding a workpiece (80) having a mark (805) representing a crystal orientation on a holding surface (302) thereof; a machining unit (16) for grinding the workpiece (80) held on the clamping table (30) with grindstones or for polishing the workpiece (80) held on the clamping table (30) with a polishing pad; a cassette platform (150, 151) for placing thereon a cassette (21, 22) for storing therein a plurality of workpieces (80) on respective shelves; an intermediate storage table (11) for temporarily placing a workpiece (80) thereon; a spinning table (120) for holding a workpiece (80) to be cleaned thereon; a robot (14) for feeding a workpiece (80) from the cassette (21, 22) placed on the cassette stage (150, 151) to the intermediate storage table (11) or for feeding a workpiece (80) held on the spinning table (120) into the cassette (21, 22) placed on the cassette stage (150, 151); a determining section (90) for determining whether a workpiece (80) has been properly machined or has not been properly machined; and a control unit (9) for executing a control operation for aligning the mark (805) of the workpiece (80) in a predetermined direction when the determining section (90) determines that the workpiece (80) has been properly machined and storing the workpiece (80) in the cassette (21, 22), and for executing a control operation for aligning the mark (805) of the workpiece (80) in a direction deviating from the predetermined direction when the determining section (90) determines that the workpiece (80) has not been properly machined and storing the workpiece (80) in the cassette (21, 22), wherein the control unit (9) is arranged to rotate the spinning table (120) with the workpiece (80) held thereon under suction by a predetermined angle in order to align the marking (805) of the workpiece (80). [2] Processing device (1) according to claim 1, in which the determination section (90) has a plurality of determination sections (901, 902), the direction deviating from the predetermined direction comprises different directions which are preset as not being consistent with each other in connection with the respective destination sections, the determining sections (901, 902) determine, in accordance with respective different determination criteria, whether the workpiece (80) has been properly machined or has not been properly machined, and when at least one of the determining sections (901, 902) determines that the workpiece (80) has not been properly machined, the control unit (9) executes a control operation for aligning the mark (805) of the workpiece (809) in the direction preset in conjunction with the determining section (901, 902) determining that the workpiece (80) has not been properly machined, and stores the workpiece (80) in the cassette (21, 22). [3] Processing device (1) according to claim 1, further comprising: a thickness measuring unit (38) for measuring the thickness of the workpiece (80), wherein the determining section (90) determines whether the workpiece (80) has been properly machined or improperly machined based on the thickness of the workpiece (80) measured by the thickness measuring unit (38). [4] Processing device (1) according to claim 3, in which the determination section (90) has a plurality of determination sections (901, 902), the direction deviating from the predetermined direction comprises different directions which are preset as not coinciding with each other in connection with the respective determination sections (901, 902), the determining sections (901, 902) determine, in accordance with respective different determination criteria, whether the workpiece (80) has been properly machined or has not been properly machined, and when at least one of the determining sections (901, 902) determines that the workpiece (80) has not been properly machined, the control unit (9) executes a control operation for aligning the mark (805) of the workpiece (80) in the direction preset in association with the determining section (901, 902) determining that the workpiece (80) has not been properly machined, and storing the workpiece (80) in the cassette (21, 22).

Images