PROCESSING DEVICE

Abstract

Machining device (2) for machining a workpiece (1), the machining device (2) comprising: a clamping table (10) holding the workpiece (1) which has several roads (3) intersecting at a holding surface (10a); a machining unit (14) that machines the workpiece (1) held by the clamping table (10) along a corresponding line of the roads (3); a machining feed unit (6) that moves the clamping table (10) and the machining unit (14) relative to each other in a direction parallel to the holding surface (10a) along a machining feed direction; a rotary unit (10e) that is capable of rotating the clamping table (10) about an axis of rotation along a direction perpendicular to the holding surface (10a);and a control device (50) that controls the clamping table (10), the machining unit (14), the machining feed unit (6) and the rotary unit (10e), wherein, when machining is interrupted, leaving an unmachined area while the machining unit (14) is caused to machine the workpiece (1) from one end to the other end of the path (3) with a relative movement of the clamping table (10) and the machining unit (14) along the machining feed direction by the machining unit (14), the control device (50) rotates the clamping table (10) by 180 degrees by the rotary unit (10e) and causes the machining unit (14) to machine the unmachined area of ​​the workpiece (1) from the other end of the path (3), while the clamping table (10) and the machining unit (14) are moved relative to each other along the machining feed direction by the machining feed unit (6).

Description

BACKGROUND OF THE INVENTIONField of the InventionThe present invention relates to a processing apparatus that processes and divides a workpiece such as a semiconductor wafer along streets.DESCRIPTION OF THE RELATED ARTIn manufacturing methods of device chips to be mounted in electronic apparatuses or the like, plate-shaped workpieces such as semiconductor wafers and plastic package substrates are processed by various processing apparatuses. Planned dividing lines in a grid shape called roads are arranged in the plate-shaped workpiece, and devices such as integrated circuits (ICs) and large scale integration circuits (LSIs) are arranged in the respective areas delimited by the roads. When the workpiece is divided along these streets, individual device chips are manufactured.A machining apparatus having a function of detecting abnormality of machining being performed is known (see Japanese Patent Application Laid-Open JP 2013-74 198 A). In this machining apparatus, when an abnormality is detected during machining of a workpiece, the machining is temporarily stopped. The user or the like of the machining apparatus checks the states of the machining apparatus and the workpiece and performs the required settings on the machining apparatus and then resumes machining. However, in some cases, the machining is resumed without thorough inspection in the state where the setting for the machining device temporarily stopped is insufficient, and the abnormality continuously occurs in the machining device. Therefore, a machining apparatus is known in which conditions for resuming machining are defined depending on the content of an abnormality occurred in machining, and a specific resumption method is required when a specific abnormality has occurred (see Japanese Patent Application Laid-Open No. 2020-77 668 A).Further information helpful for understanding the present invention can be found in the following documents:DE 10 2021 200 656 A1 relates to a method for carrying out machining for a workpiece.DE 10 2020 200 257 A1 relates to a workpiece cutting method.JP 2005-251 986 A relates to a wafer separation detection method and an apparatus for this.SUMMARY OF THE INVENTIONWhen an abnormality is detected and machining stops while a workpiece is being machined along a road, an unprocessed area remains in this road. If the road is further machined during machining after the setting of the machining apparatus is completed, the machining of the unprocessed region could be started from the position where the machining was stopped. In this case, for resuming the machining from the center of the road, a special method requiring labor and time is required. In addition, a machining tool acts on an abnormal machining track formed last before the machining stop, and an unexpected force is applied to the machining tool or the workpiece. As a result, the machining tool or the like may be broken in some cases.Alternatively, there is a case where, when an abnormality is detected and the processing stops, the further processing of the road is abandoned during the processing, and the processing is resumed from the next road. In this case, the road along which an unprocessed region remains is left as it is. Accordingly, an unshared area remains on the wafer, and the number of device chips obtained may decrease. It is also conceivable for the operator to actuate the machining device in order to process the relevant road further from a preferred position at which the machining tool or the like does not break. In this case, however, a great amount of labor and time is required, and the efficiency of the machining operation is significantly lowered.Therefore, it is an object of the present invention to provide a processing apparatus that can process a workpiece further without applying a load to a processing tool and without significantly reducing the number of manufactured device chips and the processing efficiency when an abnormality has occurred in the processing of the workpiece.According to an aspect of the present invention, there is provided a processing apparatus including: a chuck table that holds a workpiece having a plurality of roads intersecting on a holding surface; a processing unit that processes the workpiece held by the chuck table along a corresponding one of the roads; a processing supply unit that moves the chuck table and the processing unit relative to each other in a direction parallel to the holding surface along a processing supply direction; a rotating unit that is capable of rotating the chuck table about a rotation axis along a direction perpendicular to the holding surface; and a controller that controls the chuck table, the processing unit, the processing supply unit, and the rotating unit. When machining is interrupted with an unprocessed region remaining while causing the machining unit to machine the workpiece from one end to the other end of the road with relative movement of the chuck table and the machining unit along the machining feed direction by the machining unit, the controller rotates the chuck table by 180 degrees by the rotating unit and causes the machining unit to machine the unprocessed region of the workpiece from the other end of the road while moving the chuck table and the machining unit relative to each other along the machining feed direction by the machining feed unit.Preferably, the machining unit is a cutting unit that cuts the workpiece by a circular annular cutting blade.Further, the processing unit is a laser processing unit that irradiates the workpiece with a laser beam to perform laser processing on the workpiece.Specifically, the control device includes an abnormality detection section that detects an abnormality occurring while the workpiece is being machined by the machining unit and interrupts machining of the workpiece by the machining unit when the abnormality is detected by the abnormality detection section.More preferably, the processing unit further includes an imaging unit that images the workpiece held by the chuck table, and the abnormality detection section causes the imaging unit to image a position processed by the processing unit on the workpiece and detects the abnormality on the basis of a captured image captured by the imaging unit.In the machining apparatus according to the aspect of the present invention, when machining is interrupted while causing the machining unit to machine the workpiece, the controller rotates the chuck table by 180 degrees and causes the machining unit to machine the unprocessed region in the opposite direction. In this way, the unprocessed region is not left to stand and device chips are manufactured with the least possible loss. Further, in the road to be processed, the processing is not resumed from the place where the processing was interrupted, but the processing is performed from the other end side of the road where there is no abnormality. In this case, at the start of the further processing, the processing tool is not caused to act at the location of the interruption of the processing at which an abnormality exists. Therefore, breakage, etc. of the machining tool, etc. can be prevented. Moreover, the user or the like of the processing device for the subsequent processing does not need to input a particular instruction regarding the start position of the subsequent processing, etc., into the processing device and operate the processing device. In addition, a method requiring attention to perform the further processing from the center of the road is not required. Thus, the machining efficiency becomes favorable.Therefore, the present invention provides a processing apparatus that can process a workpiece further without applying a load to a processing tool and without substantially reducing the number of manufactured device chips and the processing efficiency when an abnormality has occurred in the processing of the workpiece.The above and other objects, features and advantages of the present invention, as well as the manner of realizing them, will be best understood by studying the following specification and appended claims with reference to the accompanying drawings which show a preferred embodiment of the invention, and the invention itself will be best understood thereby.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a perspective view schematically illustrating an example of a machining apparatus; FIG. 2 is a perspective view schematically illustrating a workpiece; FIG. 3 is a side view schematically illustrating a chuck table, a machining unit, and a machining feed unit; FIG. 4 is a perspective view schematically illustrating the machining unit that machines the workpiece; FIG. 5A is a plan view schematically illustrating a side of the front surface of the workpiece; FIG. 5B is a plan view schematically illustrating the side of the front surface of the workpiece in which the machining has been interrupted halfway; FIG. 6A is a plan view schematically illustrating the side of the front surface of the workpiece in which machining has been once interrupted and machining has been resumed; FIG. 6B is a plan view schematically illustrating the side of the front surface of the workpiece in which an unprocessed region is processed from an opposite side; FIG. 7A is a flowchart illustrating a flow of respective steps of a machining method of the workpiece along a road; and FIG. 7B is a flowchart illustrating a flow of respective steps of a machining method of the workpiece in which further machining is performed after the end of predetermined machining when an abnormality in machining of the workpiece has been detected.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTAn embodiment of the present invention will be described below in detail with reference to the accompanying drawings. A processing apparatus according to the present embodiment processes a plate-shaped workpiece such as a semiconductor wafer. FIG. 1 is a perspective view schematically illustrating a machining apparatus 2 and a frame unit 11 including a workpiece 1. FIG. 2 is a perspective view schematically illustrating the frame unit 11.First, the workpiece 1 to be machined by the machining device 2 will be described. For example, the workpiece 1 is a substantially circular plate-shaped wafer formed of silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), or other semiconductor materials. Alternatively, the workpiece 1 could also be a plate-shaped substrate or the like which is formed from a material such as sapphire, quartz, glass or ceramic. The glass is, for example, alkali glass, non-alkali glass, soda-lime glass, lead glass, borosilicate glass, quartz glass or the like. Further, the workpiece 1 may be a package substrate in which a plurality of chips are sealed by a resin. However, the workpiece 1 is not limited thereto.In FIG. 2, a perspective view schematically showing a circular plate-shaped semiconductor wafer is illustrated, which is an example of the workpiece 1. For example, a plurality of devices 5 such as ICs and LSIs are formed on a front surface 1 aof the workpiece 1. Planned dividing lines are defined in the workpiece 1 between the components 5, which are referred to as roads 3. Further, when cutting the workpiece 1 along the streets 3 and forming machining traces (dividing grooves) 13 for dividing the workpiece 1, as illustrated in FIG. 4, individual device chips may be formed. The cutting of the workpiece 1 can be performed by a cutting device having a circular cutting blade. The machining device 2 according to the present embodiment is, for example, a cutting device that cuts the workpiece 1. However, the workpiece 1 could also be machined by a machining device 2 other than the cutting device. For example, the processing device 2 could be a laser processing device capable of performing laser processing on the workpiece 1 by irradiation with a laser beam along the streets 3. Although the present embodiment will be described below using the example of a case where the machining device 2 is the cutting device, the machining device 2 is not limited thereto.Before the workpiece 1 is loaded into the machining apparatus 2, the workpiece 1 is connected to a division band 9 and a ring frame 7, and the frame unit 11 is formed. FIG. 2 is a perspective view schematically illustrating the workpiece 1 provided in the frame unit 11. The division band 9 is adhered to the ring frame 7 to close an opening of the ring frame 7 formed of a metal such as aluminum. Further, a rear surface 1 bside of the workpiece 1 is adhered to the division tape 9 exposed in the opening of the ring frame 7. For example, the division tape 9 is an adhesive tape having a base layer and an adhesive layer supported by the base layer. However, the division tape 9 is not limited thereto, and does not need to have the adhesive layer. For example, the division tape 9 could be a film formed of a polyolefin-based material or a film formed of a polyester-based material. In this case, the frame unit 11 may be formed by bonding the sheet to the workpiece 1 and the ring frame 7 by a method such as the thermoplastically bonding.When the frame unit 11 is formed, the workpiece 1 can be processed through the ring frame 7 and the division band 9, so that the handling of the workpiece 1 is facilitated. In addition, the device chips formed by dividing the workpiece 1 are fixed to the division tape 9, so that the handling of the device chips is also easy. When the dicing tape 9 is expanded outward in the radial direction within the opening of the ring frame 7 after the workpiece 1 is divided, a gap is generated between the individual device chips, so that picking up the device chips is also easy.Next, the processing apparatus 2 that processes the workpiece 1 will be described. FIG. 1 is a perspective view schematically illustrating a cutting device which is an example of the machining device 2 according to the present embodiment. The machining apparatus 2 has a base 4 which supports the respective components. On an upper surface of the base 4, a rectangular opening 4 aextending in the X-axis direction (machining feed direction) is formed. FIG. 3 is a side view schematically illustrating the structure inside the opening 4 a. In the opening 4 a, an X-axis moving table 6 aand a machining feed unit 6 that moves the X-axis moving table 6 ain the X-axis direction (machining feed direction) are arranged. Above the X-axis moving table 6a, a chuck table 10 is placed.The machining feed unit 6 has a pair of X-axis guide rails 6 carranged along the X-axis direction at a bottom part in the opening 4 a. The X-axis moving table 6a is slidably mounted on the X-axis guide rails 6c. At a lower portion of the X-axis moving table 6a, a ball nut member (not shown) to which an X-axis ball screw 6b parallel to the X-axis guide rails 6c is screwed is disposed. An X-axis pulse motor 6 dis connected to an end part of the X-axis ball screw 6 b. When the X-axis ball screw 6 bis rotated by the X-axis pulse motor 6 d, the X-axis moving table 6 amoves in the machining feed direction (X-axis direction), thereby displacing relative to the X-axis guide rails 6 c. When the machining feed unit 6 is operated and the X-axis moving table 6 ais moved, the machining feed of the chuck table 10 placed above the X-axis moving table 6 ais performed. The machining feed unit 6 is configured by the X-axis moving table 6 a, the X-axis ball screw 6 b, the X-axis guide rails 6 c, the X-axis pulse motor 6 d, etc., and has a function of executing the machining of the chuck table 10.The machining supply unit 6 may move a machining unit 14 to be described later along the machining supply direction instead of the chuck table 10 or move the chuck table 10 and the machining unit 14. That is, the machining feed unit 6 has a function of moving the chuck table 10 and the machining unit 14 relative to each other along the machining feed direction.As shown in FIG. 1, a dust- and drip-proof cover 8 covering the machining supply unit 6 is disposed at an upper end portion of the opening 4 a. The dust- and drip-proof cover 8 further covers the processing supply unit 6 while expanding or contracting portions thereof on the front and rear sides of the chuck table 10 in association with the movement of the chuck table 10, respectively. The chuck table 10 is installed above the X-axis moving table 6 a. A porous component 10 c(see FIG. 3 ) is embedded in an upper surface of the chuck table 10, and an upper surface of the porous component 10 cis a holding surface 10 a. Inside the chuck table 10, a suction path is formed, one end of which leads to the porous component 10 cand the other end of which is connected to a suction source configured by a pump or the like, not illustrated. Further, around the chuck table 10, clamps 10 bfor gripping the ring frame 7 of the frame unit 11 are disposed.At a corner part on a front side of the base 4 of the machining apparatus 2, a protruding part 12 protruding from the base 4 toward one side is disposed. A space is formed inside the protruding part 12, and a cassette elevator 46 is installed in this space. On an upper surface of the cartridge elevator 46, a cartridge 48 is placed in which a plurality of frame units 11 can be accommodated. The frame unit 11 including the workpiece 1 is accommodated in the cassette 48 and is loaded into the machining apparatus 2. The cassette elevator 46 raises and lowers the cassette 48.A conveying unit (not shown) that conveys the frame unit 11 from the cassette 48 to the chuck table 10 is positioned in the vicinity of the opening 4 a. The frame unit 11 conveyed from the cassette 48 by the conveying unit is placed on the holding surface 10 aof the chuck table 10. Then, when the ring frame 7 is gripped by the clamps 10 band a negative pressure generated from the suction source is caused to act on the workpiece 1 through the suction path and the porous component 10 cvia the division belt 9, the workpiece 1 is held under suction by the chuck table 10. The chuck table 10 is coupled to a rotating unit 10 ecomprising a rotational drive source such as a motor, and is rotated about a rotational axis 10 falong the direction perpendicular to the holding surface 10 a.On the upper surface of the base 4, a support structure 16 is disposed which supports the machining unit 14 machining the workpiece 1 so as to hang above the opening 4 a. An index feeding unit 18 athat moves the machining unit 14 along an index feeding direction (Y-axis direction) and a raising-lowering unit 18 bthat raises and lowers the machining unit 14 are disposed at an upper part of the front surface of the support structure 16.The index feeding unit 18a has a pair of Y-axis guide rails 20 disposed on the front surface of the support structure 16 and parallel to the Y-axis direction. A Y-axis moving plate 22 is slidably mounted on the Y-axis guide rails 20, and a nut member (not shown) is disposed on a rear surface side (front side) of the Y-axis moving plate 22 to which a Y-axis ball screw 24 is screwed in parallel with the Y-axis guide rails 20. A Y-axis pulse motor (not shown) is connected to an end part of the Y-axis ball screw 24. When the Y-axis ball screw 24 is rotated by the Y-axis pulse motor, the Y-axis moving plate 22 moves in a Y-axis direction along the Y-axis guide rails 20.The raising-lowering unit 18 bis disposed on a side of the front surface of the Y-axis moving plate 22. The elevating-lowering unit 18b has a pair of Z-axis guide rails 26 fixed to the front surface of the Y-axis moving plate 22 and parallel to the Z-axis direction. A Z-axis moving plate 28 is slidably mounted on the Z-axis guide rails 26. On a rear surface side (front side) of the Z-axis moving plate 28, a nut member (not shown) to which a Z-axis ball screw 30 parallel to the Z-axis guide rails 26 is screwed is disposed. A Z-axis pulse motor 32 is coupled to an end part of the Z-axis ball screw 30. When the Z-axis ball screw 30 is rotated by the Z-axis pulse motor 32, the Z-axis moving plate 28 moves in the Z-axis direction along the Z-axis guide rails 26.The processing unit 14 that processes the workpiece 1 held on the chuck table 10 and an imaging unit (camera unit) 34 that images an upper surface of the workpiece 1 held on the chuck table 10 are attached to a lower part of the Z-axis moving plate 28. When the Y-axis moving plate 22 is moved in the Y-axis direction by the index supply unit 18 a, the index supply of the processing unit 14 and the imaging unit 34 is performed. Further, the processing unit 14 and the imaging unit 34 move up and down in the Z-axis direction when the Z-axis moving plate 28 is moved in the Z-axis direction by the raising-lowering unit 18 b.FIG. 3 is a side view schematically illustrating a part of the machining unit 14. Further, a perspective view schematically illustrating the processing unit 14 is provided in FIG. 4. The machining unit 14 is, for example, a cutting unit that includes an annular cutting blade (machining tool) 40 and cuts the workpiece 1 with the cutting blade 40. The machining unit (cutting unit) 14 includes a spindle housing 36 in which the base end side of a spindle (not illustrated) forming a rotation axis parallel to the Y-axis direction is rotatably accommodated. Inside the spindle housing 36, a rotational drive source such as a motor that drives the spindle is housed, and the spindle is rotated when this rotational drive source is operated. The annular circular cutting blade 40 is fixed to the tip of the spindle. By rotating the spindle, the cutting blade 40 can be rotated.The cutting blade 40 has a grinding part that includes a ring-shaped joint with a metal, plastic, or the like material and abrasive grains that are formed of diamond or the like material and are dispersed and fixed in the joint. The Z-axis moving plate 28 is moved, and the cutting blade 40 is lowered to a predetermined height. Then, the machining supply unit 6 is operated and machining feed of the chuck table 10 is performed to bring the grinding part of the cutting blade 40 that is rotated into contact with the workpiece 1. This causes cutting of the workpiece 1.As illustrated in FIG. 4, the machining unit 14 further includes a blade cover 38 that covers the cutting blade 40, and a cutting water supply nozzle 42 connected to the blade cover 38. Therefore, cutting water made of purified water or the like is ejected from the cutting water supply nozzle 42 to the cutting blade 40 and the workpiece 1 while the workpiece 1 is being cut by the cutting blade 40. The cutting water removes the cutting dust and the heat generated during the machining.However, the processing unit 14 is not limited thereto. The processing unit 14 could be a laser processing unit that performs laser processing on the workpiece 1 by means of a laser beam. In this case, the processing unit 14 includes a laser oscillator and a processing head, and irradiates the workpiece 1 held on the chuck table 10 with the laser beam oscillated from the laser oscillator from the processing head. The laser processing is performed when the processing supply unit 6 is operated to perform processing supply of the workpiece 1 while the workpiece 1 is irradiated with the laser beam with the focal point of the laser beam positioned at a predetermined height.The imaging unit (camera unit) 34 images the front surface 1 aof the workpiece 1 held on the chuck table 10. The imaging unit 34 includes an imaging element such as a CCD sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, and has a function of transmitting a captured image to a controller 50 to be described later. The image captured by the imaging unit 34 is used when the processing unit 14 is positioned to process a predetermined location. Further, by capturing an image in which a region obtained after the workpiece 1 is machined appears, it can be judged whether or not the machining result is favorable.A cleaning unit 44 that cleans the workpiece 1 obtained after the machining is disposed on a rear side relative to the opening 4 aof the base 4. The workpiece 1 obtained after the machining is conveyed from the chuck table 10 to the cleaning unit 44 by a conveying mechanism not illustrated. The cleaning unit 44 includes a rotary table that holds the workpiece 1 in a cylindrical space under suction. Further, above the turntable, a nozzle that ejects a fluid for cleaning (typically, a binary fluid in which water and air are mixed) to the workpiece 1 is disposed. When the rotary table on which the workpiece 1 is placed is rotated and the fluid is ejected from the nozzle for cleaning, the workpiece 1 can be cleaned. The workpiece 1 cleaned by the cleaning unit 44 is accommodated in the cassette 48 by, for example, a conveying mechanism (not illustrated).The processing apparatus 2 further includes the control device (control unit) 50 that controls the respective components including the chuck table 10, the processing unit 14, the processing supply unit 6, the rotating unit 10 e, the imaging unit 34, the index supply unit 18 a, and the raising-lowering unit 18 b. The control device 50 is configured by, for example, a computer including a processing device such as a central processing unit (CPU), a main storage device such as a dynamic random access memory (DRAM), and an auxiliary storage device such as a flash memory. The functions of the control device 50 are implemented by the operation of the processing apparatus and so on according to the software stored in the auxiliary storage device.The machining conditions for machining the workpiece 1 are input and registered in advance in the control device (unit) 50. Then, the controller 50 controls the respective components according to the machining conditions. The machining conditions are set according to the kind of the workpiece 1 and the desired machining result. Further, the controller 50 controls the respective components with reference to the information transmitted from the respective components to cause the workpiece 1 to be machined in a predetermined method. That is, the controller 50 includes a storage portion 50 ain which various information including various machining conditions can be registered, and a machining control portion 50 bthat controls the respective components according to the machining conditions registered in the storage portion 50 aand performs the machining of the workpiece 1.In addition, the processing apparatus 2 may include a touch panel-equipped display (not illustrated) used for inputting a command to the controller 50 and displaying various kinds of information. Further, the processing device 2 may include a warning unit (not illustrated) that alerts the user through a lamp or a warning sound. In addition, the machining apparatus 2 may include a measurement unit such as an ammeter that measures the load current value of the rotational drive source of the spindle connected to the cutting blade 40, and a pressure meter that measures the pressure value of a negative pressure generated by the suction source connected to the chuck table 10, such as a pump.In the processing apparatus 2, the frame unit 11 accommodated in the cassette 48 is successively conveyed to the chuck table 10 and held by the chuck table 10 under suction. Then, the workpiece 1 on the chuck table 10 is machined by the machining unit 14 under a predetermined machining condition. The processed workpiece 1 is cleaned by the cleaning unit 44 and then accommodated in the cassette 48. After finishing the machining of the workpieces 1 of all the frame units 11 accommodated in the cassette 48 and loaded in the machining apparatus 2, the cassette 48 is unloaded from the machining apparatus 2.In the machining apparatus 2, it may be rare cases that a disturbance occurs in some components in machining the workpiece 1 and the machining does not proceed as scheduled. In this case, unchanged continuation of the machining frequently leads not only to failure in achieving a predetermined machining result but also to breakage of the workpiece 1 and the cutting blade (cutting tool) 40. therefore, it is preferable that the machining apparatus 2 has a function of detecting irregular machining being performed, and it is preferable to temporarily stop the machining of the workpiece 1 and issue a warning to the user or the like of the machining apparatus 2 when a kind of abnormality is detected while the machining is being performed. Further, when the machining apparatus 2 is stopped due to an abnormality, the user or the like checks the states of the machining apparatus 2, the workpiece 1, and so on, and performs the necessary setting for the machining apparatus 2, and then causes the machining apparatus 2 to resume machining.Here, when an abnormality is detected and the machining is stopped while the workpiece 1 is machined along the road 3, an unprocessed area is left in the road 3 in the middle of the machining. A more detailed description will be given below. FIG. 5A is a plan view schematically illustrating the front surface 1 aof the workpiece 1 that is unprocessed. FIG. 5B is a plan view schematically illustrating the workpiece 1 when an abnormality is detected and machining is stopped while the machining device 2 is executing machining. When the workpiece 1 is machined (cut) by the machining unit (cutting unit) 14, the machining traces (cutting grooves) 13 are sequentially formed in the respective roads 3. Further, as illustrated in FIG. 5B, in a case where an abnormality is detected and the processing is stopped, when a position 15 is processed while the processing is being performed from one end 3 ato the other end 3 bof a certain road 3, an unprocessed region 3 cremain from the position 15 to the other end 3 bof the road 3.Thereafter, when the machining of the workpiece 1 is resumed by adjustment of the machining apparatus 2, in a case where the machining of the unprocessed region 3 cis resumed from the position 15, an unexpected force may act on the cutting blade (cutting tool) 40 or the workpiece 1, and its breakage may occur. The occurrence of an abnormality in the machining track 13 formed in the vicinity of the position 15 immediately before the interruption of machining in the machining apparatus 2 is one of the reasons for this.For example, it is conceivable that the workpiece 1 is not suctioned and held with sufficient force and the workpiece 1 floats or vibrates when the negative pressure caused to act on the workpiece 1 by the chuck table 10 is weak in machining the position 15. Further, it is conceivable that the cutting blade 40 etc. is not sufficiently cooled and the abrasive part of the cutting blade 40 thermally expands when the amount of cutting water supplied to the cutting blade 40 etc. is small in the processing of the position 15. In such a case, the abnormal machining track 13 may be formed at the position 15 on the workpiece 1.In addition, when the drive current of the rotational drive source that rotates the spindle to which the cutting blade 40 is connected does not have normal fluctuations, there is a possibility that breakage or deformation of the cutting blade 40 or meandering or positional deviation of the machining track 13 has occurred. When the machining is resumed at the position 15 where the abnormality has occurred as described above, an unexpected force is applied to the cutting blade 40, etc.Further, when the machining is stopped, the raising-lowering unit 18 bis operated, and the cutting blade 40 is lifted from the workpiece 1 and moved away from the workpiece 1. When the machining is resumed, the cutting blade 40 is lowered near the position 15 and caused to cut gently and gently from the upper side into the workpiece 1. However, when the cutting blade 40 is caused to cut into the workpiece 1 from the upper side, breakage called chipping may occur at the outer periphery of the machining track 13. Therefore, the quality of the formed machining trace 13 could be degraded, and in some cases, breakage of a formed chip could also occur.Thus, when an abnormality is detected and the machining is stopped, the further machining is not performed for the rough area 3 cof the road 3 in the middle of the machining, and the machining is resumed from the next road 3. In this case, the road 3 processed at the time of stopping the processing is left to stand. This causes an unshared area in the workpiece 1, and there is a problem in that the number of chips obtained decreases. It is also conceivable that the operator operates the machining device 2 to resume machining of the workpiece 1 normally from the vicinity of the region where machining has been stopped. In this case, however, a great amount of labor and time is required, and the efficiency of the machining operation is significantly lowered. Therefore, in the processing apparatus 2 according to the present embodiment, when the processing is stopped due to an abnormality, the workpiece 1 is further processed without applying a load to the cutting blade (processing tool) 40, etc., and without significantly reducing the number of manufactured device chips and the processing efficiency. The following will continue the description of the machining apparatus 2 according to the present embodiment, centering on a configuration that interrupts machining when an abnormality is detected in machining, and then further machines the workpiece 1.First, a configuration that monitors whether or not an abnormality exists in the machining and stops the machining when an abnormality is detected will be described. In the machining apparatus 2, the operating state of the respective components is monitored by an ammeter that measures the load current value of the rotational drive source of the spindle connected to the cutting blade 40, a pressure meter that measures the pressure value of the negative pressure acting on the chuck table 10, and a flow meter that measures the flow rate of the cutting water. Alternatively, in the machining apparatus 2, the workpiece 1 obtained after machining is photographed by the imaging unit 34, and the machining result is evaluated based on a captured image.For example, the controller 50 of the machining apparatus 2 includes an abnormality detection unit 50 cthat detects an abnormality occurring during machining of the workpiece 1 by the machining unit 14. The abnormality detection unit 50 cdetects occurrence of an abnormality when the load current value of the rotational drive source of the spindle, the pressure value of the negative pressure acting on the chuck table 10, or the flow rate of the cutting water has an unusual variation. Alternatively, the abnormality detection unit 50 ccauses the imaging unit 34 to image a position machined by the machining unit 14 on the workpiece 1, and detects an abnormality based on an image captured by the imaging unit 34. The machining control portion 50 bof the controller 50 interrupts the machining of the workpiece 1 by the machining unit 14 when an abnormality has been detected by the abnormality detection unit 50 c. For example, the processing control section 50 bstops the processing supply unit 6 to stop the processing of the chuck table 10 and so on, and operates the raising-lowering unit 18 bto raise the cutting blade 40.Further, for example, the controller 50 may cause the imaging unit 34 to sequentially capture the machining tracks 13 formed in the workpiece 1 by machining, and sequentially display the obtained images on the touch panel-equipped display. The user or the like of the machining apparatus 2 could monitor whether or not there is an abnormality by visually recognizing the machining tracks 13 appearing in the captured and sequentially displayed images. When the user or the like detects the occurrence of an abnormality, he inputs a command to end the machining to the machining device 2 and stops the machining. That is, the detection of an abnormality need not be performed by functions of the controller 50.In this manner, the machining with the unprocessed region 3 con the left is interrupted while causing the machining unit 14 to machine the workpiece 1 from the one end 3 ato the other end 3 bof the road 3 with relative movement of the chuck table 10 and the machining unit 14 along the machining feed direction by the machining feed unit 6. In this case, the controller 50 acquires information regarding the road 3 where the unprocessed area 3 cremain in the workpiece 1 and the position 15 where the processing has been stopped, and causes the storage portion 50 ato store the information.Then, the controller 50 rotates the chuck table 10 with the rotating unit 10 eby 180 degrees before resuming the interrupted machining. Alternatively, the controller 50 resumes the machining from the road 3 to be machined next to the road 3 in which the machining has been interrupted, and rotates the chuck table 10 by 180 degrees by the rotating unit 10 eafter the machining has advanced to a predetermined state. Thereafter, the controller 50 causes the machining unit 14 to machine the unprocessed region 3 cof the workpiece 1 from the other end 3 bof the road 3 while moving the chuck table 10 and the machining unit 14 relative to each other along the machining feed direction by the machining feed unit 6. That is, the road 3 in which the unprocessed region 3 cis located is processed in the opposite direction.FIG. 6A is a plan view schematically illustrating the workpiece 1 in which, after the cut-off of the machining, the road 3 in which the unprocessed region 3 cremains is left and the machining has been performed along all the other roads 3 that are parallel to the remaining road 3. Further, FIG. 6B is a plan view schematically illustrating the workpiece 1 for which the chuck table 10 has been rotated by 180 degrees thereafter by the rotating unit 10 e, and the road 3 in which the unprocessed region 3 cremains has been further processed in the opposite direction, and a processing lane 17 has been formed. In FIG. 6B, the machining track 17 formed by the further machining is shown by a broken line for ease of explanation.The controller 50 reads out the information concerning the road 3 including the unprocessed area 3c, the information concerning the position 15, etc. stored in the storage section 50a, and determines the position from which the further processing is to be performed. Then, the further processing is started from the other end 3b of the road 3. This further processing is performed similarly to the normal processing performed from the one end 3 aof the road 3. Therefore, no unexpected force acts on the cutting blade (machining tool) 40 or the workpiece 1, unlike the case where the further machining is started from the position 15 in the vicinity of which the abnormal machining track 13 is formed. Further, no abnormal chipping is formed on the outer periphery of the machining track 17 unlike the case where the cutting blade 40 is caused to cut into the workpiece 1 from the upper side to perform the post-machining.When the further processing is performed in this manner, the unprocessed region 3 cdoes not remain in the workpiece 1, and therefore the maximum number of device chips can be manufactured from the workpiece 1. However, there is a possibility that normal processing is not performed and the normal processing track 13 is not formed in the vicinity of the position 15, and it is also conceivable that a high quality device chip is not obtained from the vicinity of the position 15. Therefore, it is preferable that a device chip formed from the workpiece 1 in the vicinity of the position 15 is subjected to a special test step or is distinguished from the other positioned device chips.The further processing from the other end 3b of the road 3 could be terminated immediately before the position 15 representing the end point of the unprocessed region 3c. In this case, the cutting blade (machining tool) 40 does not machine the position 15 where the abnormal machining track 13 may be formed, and therefore breakage of the cutting blade 40 and so on due to execution of machining in the vicinity of the abnormal machining track 13 is prevented. However, the machining apparatus 2 according to the present embodiment is not limited thereto, and the further machining may be performed up to the position 15.When the cutting blade 40 of the processing unit 14 has advanced to the position 15 or the vicinity thereof, the processing is terminated by operating the raising-lowering unit 18 bto raise the cutting blade 40. Then, after the entire predetermined processing including the subsequent processing is performed for the workpiece 1, the frame unit 11 including the workpiece 1 is performed by the chuck table 10.As described above, in the machining apparatus 2 according to the present embodiment, even when an abnormality is detected in machining of the workpiece 1 and machining is interrupted, the road 3 including the unprocessed region 3 cmay be further machined without causing the cutting blade 40 to break, etc. Further, when the controller 50 causes the storage portion 50 ato store information regarding the road 3 for which machining is required and the position 15 at which the machining has been stopped, the machining can be easily and quickly executed without giving a detailed instruction regarding the machining by the user or the like of the machining apparatus 2.Preferably, the frequency of occurrence of abnormality in the machining of the workpiece 1 by the machining device 2 is low. In fact, the abnormality occurrence frequency is low, and the number of workpieces 1 for which further processing is performed by the processing device 2 according to the present embodiment is limited. However, in the machining apparatus 2 according to the present embodiment, the further machining of the workpiece 1 for which the further machining is required is efficiently and stably performed, and thus the machining is completed early also for other workpieces 1 machined thereafter. Therefore, the machining apparatus 2 according to the present embodiment has an advantage not only for machining the workpiece 1 for which further machining is required but also for machining the workpiece 1 for which further machining is not finally required. Even if an abnormality is not detected while a plurality of workpieces 1 are being machined in the machining apparatus 2, and the machining of all the workpieces 1 is finally performed without delay, it is advantageous if the machining apparatus 2 has only a function that enables efficient execution of the further machining. For example, the operation of the processing device 2 does not require inefficient post-processing.Next, processing methods of the workpiece 1 performed in the processing apparatus 2 according to the present embodiment will be described. The following explains the structure and operation of the machining apparatus 2 according to the present embodiment with respect to the machining methods. FIG. 7A is a flowchart illustrating the flow of respective steps of a machining method for machining the workpiece 1 along a road 3. FIG. 7B is a flowchart illustrating the flow of respective steps of a machining method for further machining the workpiece 1. In the machining apparatus 2, the machining process of the workpiece 1 to be described with FIG. 7A is repeatedly performed and the machining is performed along all the streets 3. Then, after the workpiece 1 is machined along some of the streets 3 or after the workpiece 1 is machined along all the streets 3, the machining process described with FIG. 7B is performed to finish the workpiece 1 as necessary.First, the frame unit 11 is conveyed to the chuck table 10 of the processing apparatus 2, and the chuck table 10 is caused to suck and hold the workpiece 1 with the intermediary of the division belt 9. FIG. 3 schematically shows a sectional illustration of the workpiece 1 held by the clamping table 10 under suction. Next, the upper surface of the workpiece 1 is imaged by the imaging unit 34 to detect the extending direction of the streets 3, and the chuck table 10 is rotated by the rotating unit 10 eto align the alignment of the streets 3 with the machining feed direction (X-axis direction). Then, the processing procedure whose flow is shown in FIG. 7A is executed for the road 3 to be processed first. First, the cutting blade 40 is positioned over an extended line of the road 3 to be processed first, the rotation of the cutting blade 40 is started, and the cutting blade 40 is lowered to a predetermined height position. Then, the machining feed unit 6 is operated, and the machining of the chuck table 10 and the machining unit 14 is relatively performed. Then, the abrasive part of the cutting blade 40 comes into contact with the workpiece 1, and the processing of the workpiece 1 is started (S 10). At this time, the cutting water is supplied from the cutting water supply nozzle 42 and so on to the cutting blade 40.The abnormality detection unit 50 cor the user of the machining apparatus 2 monitors the machining apparatus 2 while the workpiece 1 is being machined. Then, when the abnormality detection unit 50 cdetermines an abnormality (S 20), the controller 50 interrupts the processing by the processing unit 14 (S 50). Alternatively, when the user or the like of the machining apparatus 2 detects a kind of abnormality (S 20), the user or the like inputs a command to interrupt the machining by the machining unit 14 to the controller 50, and interrupts the machining (S 50). Then, when an abnormality is detected and the processing in the processing apparatus 2 is interrupted, the position at which the abnormality has occurred is acquired (S 60). That is, the storage portion 50 aof the controller 50 stores information related to the position 15 at which the abnormality of the workpiece 1 has been detected and the machining has been stopped, the road 3 in which the unprocessed region 3 cremains, and so on.Further, in a case where an abnormality is not detected while the workpiece 1 is being machined along this road 3 (S 20), if the machining has not advanced to the end point of the road 3 (S 30), the machining is continued without any change (S 40). Then, the processing is continued until the end point of the road 3 as long as no abnormality is detected. Thereafter, when the cutting blade 40 has machined the end point of the road 3, the machining of this road 3 ends (S 70).After the processing of the workpiece 1 along the one street 3 is completed, index feeding of the workpiece 1 is performed, and the workpiece 1 is similarly cut along the next street 3. That is, the machining method illustrated in FIG. 7A is newly executed. Then, after the processing of all the roads 3 along the one direction is completed, the rotating unit 10 eis operated, and the orientation of the roads 3 along the other direction is associated with the processing feeding direction. Then, the machining of the workpiece 1 is similarly advanced, and the machining is completed along all the streets 3. When the workpiece 1 is machined normally along all the streets 3, it is divided into individual device chips. Further processing is performed when processing is not normal in some of the roads 3 and an abnormality is detected, so that processing is interrupted and the unprocessed region 3 cis left.In FIG. 7B, the flow of the machining method of a workpiece is illustrated in which the re-machining is performed according to the necessity after all the roads 3 have been machined. For example, after each step is executed along the flow shown in FIG. 7A and the processing is performed for all the roads 3 (S 80), if the road 3 in which an abnormality in the processing is detected and the processing is interrupted is present (S 90), the further processing is prepared for that road 3 in which the unprocessed region 3 cis left. In this case, first, the rotating unit 10 eis operated and the chuck table 10 is rotated to connect the orientation of the road 3 that becomes the target of machining with the machining feed direction (X-axis direction). At this time, the chuck table 10 is rotated by 180 degrees from the state where this road 3 has been machined first by the rotating unit 10e, so that the machining could be in the opposite direction to the direction where this road 3 has been machined first.The chuck table 10 does not need to rotate by 180 degrees at once. That is, it is sufficient to achieve the state in which the chuck table 10 is rotated 180 degrees from the state in which the road 3 that is the target of the further processing has been processed first. More specifically, the chuck table 10 is rotated 180 degrees after an abnormality is detected and the processing of this road 3 is interrupted, the processing of other roads 3 parallel to this road 3 is performed, and thereafter the further processing is performed. Further processing could be performed immediately after an abnormality is detected and processing of this road 3 is interrupted. Also in this case, the chuck table 10 is rotated by 180 degrees. On the other hand, when the processing of other roads 3 that are not parallel to this road 3 is performed after an abnormality is detected and the processing is interrupted during the processing of this road 3, the chuck table 10 has already been rotated at this time. Thereafter, when the further machining is performed, the chuck table 10 is rotated to cause this road 3 which becomes the target of the further machining to be further machined in the opposite direction. This achieves the state in which the chuck table 10 is rotated 180 degrees from the state in which this road 3 has been first machined.As described above, rotating the chuck table 10 180 degrees means that the road 3 which becomes the target of machining is oriented in the opposite direction to the direction in the normal machining. After the chuck table 10 is rotated as described above (S 100), the further processing is thereafter performed (S 110).When the machining is executed, the machining control section 50 breads out the information relating to the position 15 at which the machining has been stopped, the road 3 in which the unprocessed area 3 cremains, and so on, which have been stored in the storage section 50 a. Then, in the further processing, the unprocessed region 3 cis processed from the other end 3 b(see FIG. 6B, etc.) of the road 3. That is, the cutting blade 40 is positioned outward relative to the other end 3 bof the road 3, the cutting blade 40 is rotated, and the processing unit 14 is lowered to a predetermined height position. Thereafter, the machining feed unit 6 is operated, and the relative machining feed of the chuck table 10 and the machining unit 14 is executed. This causes the cutting blade 40 to cut from the other end 3 bside into the unprocessed region 3 cof the road 3. Then, the machining track 17 is formed. The further processing is carried out until the processing track 17 is formed in the vicinity of the position 15 or at the position 15.If an abnormality is never detected and the machining is not interrupted while the workpiece 1 is being machined along all the roads 3 (S 90), the further machining need not be performed. After the further machining of the workpiece 1 (S 110) is completed or after it is determined that the further machining is not necessary, the frame unit 11 is executed by the chuck table 10.After the workpiece 1 is divided into individual device chips by the processing, the individual device chips are picked up by the division tape 9 and mounted on a predetermined mounting device. In the processing apparatus 2 according to the present embodiment, even if some kind of abnormality has occurred in the processing of the workpiece 1, as many device chips as possible can be efficiently manufactured.The present invention is not limited to the description of the above-described embodiment, and can be embodied with various changes. For example, in the above-described embodiment, the case where the plurality of streets 3 set on the front surface 1 aof the workpiece 1 are machined one by one from one end of the workpiece 1 has been described, as illustrated in FIG. 5B, etc. However, the processing apparatus 2 according to an aspect of the present invention is not limited thereto. That is, there is no particular limitation to the order of processing of the respective roads 3.

Claims

A processing apparatus (2) that processes a workpiece (1), the processing apparatus (2) comprising: a chuck table (10) that holds the workpiece (1) having a plurality of streets (3) intersecting on a holding surface (10a); a processing unit (14) that processes the workpiece (1) held by the chuck table (10) along a corresponding one of the streets (3); a processing supply unit (6) that moves the chuck table (10) and the processing unit (14) relative to each other in a direction parallel to the holding surface (10a) along a processing supply direction; a rotating unit (10e) that is capable of rotating the chuck table (10) about an axis of rotation along a direction perpendicular to the holding surface (10a); and a controller (50) that moves the chuck table (10), the processing unit (14) controls the processing supply unit (6) and the rotating unit (10e), wherein when processing is interrupted with an unprocessed region remaining while the processing unit (14) is caused to process the workpiece (1) from one end to the other end of the road (3) with a relative movement of the chuck table (10) and the processing unit (14) along the processing supply direction by the processing unit (14), the controller (50) rotates the chuck table (10) by 180 degrees by the rotating unit (10e), and causes the processing unit (14) to process the unprocessed region of the workpiece (1) from the other end of the road (3) while the chuck table (10) and the processing unit (14) are moved relative to each other along the processing supply direction by the processing supply unit (6).The processing apparatus (2) according to claim 1, wherein the processing unit (14) is a cutting unit that cuts the workpiece (1) with a circular annular cutting blade (40).The processing apparatus (2) according to claim 1, wherein the processing unit (14) is a laser processing unit (14) that irradiates the workpiece (1) with a laser beam to perform laser processing on the workpiece (1).The machining apparatus (2) according to any one of the preceding claims, wherein the controller (50) includes an abnormality detecting section that detects an abnormality occurring while the workpiece (1) is being machined by the machining unit (14), and that interrupts machining of the workpiece (1) by the machining unit (14) when the abnormality is detected by the abnormality detecting section.The processing apparatus (2) according to claim 4, further comprising: an imaging unit (34) that images the workpiece (1) held by the chuck table (10), wherein the abnormality detection section causes the imaging unit (34) to image a position processed by the processing unit (14) on the workpiece (1) and detect the abnormality based on a captured image captured by the imaging unit (34).

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