Method of processing and cutting apparatus for a plurality of wafers

Abstract

The present application provides a wafer processing method and a cutting device, without changing the movable range of the conveying unit relative to the usual specifications, the number of wafers processed per unit time is increased compared to the case where the first cassette is replaced with a second cassette after processing and conveying all the wafers received into the first cassette. A wafer processing method is provided, which has the following steps: a cassette replacement step, after receiving all the wafers except the final wafer into the first cassette, the first cassette is removed from the cassette placement table, and a second cassette different from the first cassette is placed on the cassette placement table; a conveying start step, after the cassette replacement step, the wafer conveying from the second cassette to the chuck table is started; and a final wafer placement step, after the conveying start step, the final wafer cut by the cutting step is placed on the wafer placement part, which is arranged on the lower side of the cassette placement table and is lifted together with the cassette placement table.

Description

TECHNICAL FIELD

[0001] The present application relates to a processing method of a plurality of wafers in which the plurality of wafers are sequentially cut along a division predetermined line, and a cutting apparatus that sequentially cuts a plurality of wafers. BACKGROUND

[0002] In a manufacturing process of a semiconductor device chip, a plurality of division predetermined lines are set in a lattice shape on a front surface of a disc-shaped wafer, and a device such as an IC (Integrated Circuit) is formed in each of a plurality of regions divided by the plurality of division predetermined lines. Then, the wafer is divided into a plurality of semiconductor device chips by cutting the wafer along each division predetermined line.

[0003] In order to cut the wafer, for example, a cutting apparatus is used. The cutting apparatus has a conveyance unit that conveys the wafer, a chuck table that suction-holds the wafer, and a cutting unit that has a cutting tool that cuts the wafer suction-held by the chuck table (for example, refer to Patent Literature 1).

[0004] In cutting the wafer, first, a first cassette that accommodates a plurality of wafers is arranged in the cutting apparatus. Then, the wafers are sequentially conveyed out of the first cassette by the conveyance unit, and the wafers after cutting and cleaning are sequentially conveyed into the first cassette.

[0005] Then, after all the wafers once accommodated in the first cassette are conveyed into the first cassette, another cassette (a second cassette) that accommodates a plurality of wafers is arranged in the cutting apparatus in place of the first cassette. Then, the wafers are sequentially conveyed out of the second cassette, and cutting and cleaning are performed as in the case of the first cassette.

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2011-159823

[0007] Therefore, the operation of the cutting apparatus needs to be stopped at the time of changing the cassette, and thus the number of wafers processed per unit time decreases. In contrast, in order to mount a plurality of cassettes in the cutting apparatus at the same time, it is also possible to consider changing the specifications of a general cutting apparatus so as to provide a plurality of cassette placement tables at the same height position, but a large modification such as expanding the movable range of the conveyance unit is required. SUMMARY

[0008] The present application is achieved in view of the above-described problems, and aims to increase the number of wafers processed per unit time without changing the movable range of the conveyance unit with respect to the general specifications, and compared to the case where the first cassette is changed to the second cassette after processing and conveying all the wafers accommodated into the first cassette.

[0009] According to one embodiment of the present application, there is provided a method of processing a plurality of wafers, the method comprising: placing a first cassette containing a plurality of wafers on a cassette placement table; sequentially transporting the wafers from the first cassette to a chuck table; determining whether the wafer transported to the chuck table is a final wafer that is the last wafer to be transported from the first cassette; cutting the wafer held by the chuck table using a cutting unit; after cutting the wafer that is not the final wafer, storing the wafer in the first cassette; after storing all the wafers except the final wafer in the first cassette, unloading the first cassette from the cassette placement table and placing a second cassette containing a plurality of wafers and different from the first cassette on the cassette placement table; after the step of placing the second cassette, starting to transport the wafers from the second cassette to the chuck table; and after the step of starting to transport the wafers, placing the final wafer on a wafer placement portion, the wafer placement portion being disposed below the cassette placement table and being raised and lowered together with the cassette placement table.

[0010] Preferably, the method of processing a plurality of wafers further comprises: after the step of placing the final wafer, taking out the final wafer placed on the wafer placement portion from the wafer placement portion and storing the final wafer in the first cassette.

[0011] According to another aspect of the present application, there is provided a cutting apparatus that, after cutting a plurality of wafers each having a device formed in a region divided by a plurality of division predetermined lines provided on a front side along each division predetermined line, respectively, houses the plurality of wafers in a cassette, respectively, the cutting apparatus including: a chuck table that holds a wafer; a cutting unit that has a spindle and a cutting tool attached to one end side of the spindle; a cassette mechanism that has a cassette placement table on which a first cassette in which the plurality of wafers are housed is placed and a wafer placement portion provided on a lower side of the cassette placement table and raised and lowered together with the cassette placement table; a conveyance unit that conveys a wafer between the cassette mechanism and the chuck table; a control unit that includes a determination portion that determines a wafer last conveyed from the first cassette as a final wafer of the first cassette, and a notification portion that issues a message urging replacement of the first cassette in a case where all wafers other than the final wafer that were housed in the first cassette are housed in the first cassette after cutting, the control unit controlling the conveyance unit so as to convey all wafers other than the final wafer among the wafers after cutting into the first cassette and convey the final wafer onto the wafer placement portion, and in a case where a second cassette in which the plurality of wafers are housed and which is different from the first cassette is placed on the cassette placement table after all wafers other than the final wafer are housed in the first cassette, start conveying a wafer from the second cassette to the chuck table before the final wafer after cutting is placed on the wafer placement portion.

[0012] In the method of processing a plurality of wafers of one embodiment of the present application, there is a step of: a cassette replacement step of, after housing all wafers other than a final wafer in a first cassette, unloading the first cassette from a cassette placement table and placing a second cassette in which the plurality of wafers are housed and which is different from the first cassette on the cassette placement table; a conveyance start step of, after the cassette replacement step, starting conveying a wafer from the second cassette to a chuck table; and a final wafer placement step of, after the conveyance start step, placing the final wafer after cutting by a cutting step on a wafer placement portion provided on a lower side of the cassette placement table and raised and lowered together with the cassette placement table.

[0013] Thus, before returning the final wafer to the first cassette, it is possible to start conveying a wafer from the second cassette to the chuck table. Therefore, it is possible to increase the number of wafers processed per unit time compared to a case where the first cassette is replaced with the second cassette after processing and conveying all wafers housed in the first cassette.

[0014] Further, since the wafer placement portion provided on the lower side of the cassette placement table is raised and lowered together with the cassette placement table, the movable range of the conveyance unit is not changed, and the conveyance unit can place the final wafer on the wafer placement portion. Therefore, it is not necessary to change the movable range of the conveyance unit with respect to a normal specification. Attached Figure Description

[0015] Figure 1 It is a three-dimensional diagram of the cutting device.

[0016] Figure 2 This is a partial sectional side view of a box mechanism, etc.

[0017] Figure 3 It is a 3D image of a chip, etc.

[0018] Figure 4 This diagram illustrates the processing of multiple wafers in a time sequence.

[0019] Figure 5 This diagram shows the process of cleaning wafer #1 and cutting wafer #2.

[0020] Figure 6 This diagram illustrates the processing of wafers #(N-1) and #N.

[0021] Figure 7 This is a diagram showing the box replacement steps.

[0022] Label Explanation

[0023] 2: Cutting device; 4: Base; 4a, 4b, 4e: Openings; 4c, 4d: Supports; 6: Box mechanism; 6a: Lifting platform; 6b: Wafer placement section; 6c: Opening; 6d: Box placement stage; 6e: Box; 6e-1: First box; 6e-2: Second box; 6f: Sensor; 8: Lifting mechanism; 10: Worktable cover; 12: Dustproof and drip-proof cover; 14: Chuck worktable; 14a: Holding surface; 14b: Fixture; 16: Lower arm unit; 16a: Moving mechanism; 16b: Cylinder; 16c: Rod; 16d: First arm; 16e: Adsorption pad; 16f: Holding mechanism; 18 20: Y-axis moving plate; 22: Z-axis pulse motor; 22: Cutting unit; 22a: Spindle housing; 22b: Spindle; 22c: Cutting tool; 24: Imaging unit; 26: Cleaning unit; 30: Upper arm unit; 30a: Moving mechanism; 30b: Cylinder; 30c: Rod; 30d: First arm; 30e: Adsorption pad; 32: Control unit; 34: Judgment unit; 36: Touch panel; 38: Alarm light; 40: Notification unit; 11: Chip; 11a: Front; 11b: Back; 13: Pre-division line; 15: Component; 17: Adhesive tape; 19: Frame; 21: Chip unit. Detailed Implementation

[0024] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a perspective view of cutting device 2. Additionally, Figure 1The X-axis direction (machining feed direction), the Y-axis direction (index feed direction), and the Z-axis direction (vertical direction, cutting feed direction) are perpendicular to each other.

[0025] The cutting device 2 has a base 4 that supports each structural element. An opening 4a is provided at a corner portion in front of the base 4. Inside the opening 4a is provided Figure 2 The illustrated cassette mechanism 6. Figure 2 is a partial cross-sectional side view of the cassette mechanism 6 or the like.

[0026] The cassette mechanism 6 has a lifting table 6a. The lifting table 6a is lifted along the Z-axis direction by a lifting mechanism 8 of a ball screw type. On the upper surface of the lifting table 6a is disposed a wafer placement portion 6b. The wafer placement portion 6b is a cuboid-shaped case whose length in the height direction is smaller than each of the length in the longitudinal direction and the length in the lateral direction.

[0027] The inside of the wafer placement portion 6b is hollow, and the wafer placement portion 6b has openings 6c in two side surfaces that are substantially perpendicular to the Y-axis direction. The openings 6c have a size that allows one wafer unit 21 described later to pass therethrough.

[0028] On the upper side of the wafer placement portion 6b is provided a flat plate-shaped cassette placement table 6d that has substantially the same size as the upper surface of the wafer placement portion 6b. On the cassette placement table 6d is placed a cassette 6e that houses a plurality of wafer units 21 (i.e., wafers 11).

[0029] Here, reference is made to Figure 3 The wafer 11 or the like is described. Figure 3 is a perspective view of the wafer 11 or the like. The wafer 11 is formed of a semiconductor material such as silicon, for example, and has a disc shape.

[0030] A plurality of division intended lines (streets) 13 are provided on the front surface 11a of the wafer 11 in a manner that intersects each other. In a plurality of regions divided by the plurality of division intended lines 13 are respectively formed devices 15 such as ICs (Integrated Circuits).

[0031] In addition, the wafer 11 is not limited in material, shape, configuration, size, or the like. For example, the wafer 11 can be formed of a semiconductor other than silicon, ceramic, resin, metal, or the like. Also, the devices 15 are not limited in kind, number, shape, configuration, size, arrangement, or the like.

[0032] On the back surface 11b side that is on the side opposite to the front surface 11a is attached a circular adhesive tape (dicing tape) 17 that is larger in area than the wafer 11. On the outer peripheral portion of the adhesive tape 17 is fixed a ring-shaped frame 19 of metal.

[0033] That is, the wafer unit 21 is formed in a manner that the wafer 11 is supported by the frame 19 with the aid of the adhesive tape 17. A plurality of wafer units 21 are housed in one cassette 6e. The cassette 6e has a pair of side walls and connecting portions connected to upper and lower portions of the pair of side walls, respectively.

[0034] A plurality of shelves (not shown) are provided on the pair of side walls in the height direction of the cassette 6e, and one wafer unit 21 is placed on each of the shelves. In addition, the side portions of the cassette 6e on both sides in the width direction of the pair of side walls become openings.

[0035] Here, returning Figure 2 to the cassette mechanism 6 will be described. The cassette mechanism 6 includes a wafer placement portion 6b and a cassette placement table 6d disposed on the lifting table 6a, and a cassette 6e. The cassette mechanism 6 is raised and lowered together in the Z-axis direction by the lifting mechanism 8.

[0036] The wafer unit 21 housed in the cassette 6e is detected by a sensor 6f disposed on the upper portion of the side wall disposed on the rear (one side in the Y-axis direction) among the side walls of the base 4 constituting the opening 4a.

[0037] The sensor 6f of the present embodiment is a reflection type mapping sensor having a light emitting portion including a light source such as an LED (Light Emitting Diode) and a light receiving portion including a photodiode or the like photoelectric conversion element that receives reflected light of light irradiated from the light emitting portion.

[0038] The sensor 6f irradiates light to the inside of the cassette 6e through the opening of the cassette 6e and receives reflected light from the frame 19, thereby detecting the presence or absence of the wafer unit 21. Specifically, the cassette 6e is raised by the lifting mechanism 8, and the sensor 6f receives the reflected light by the light receiving portion.

[0039] For example, the number of wafer units 21 (i.e., wafers 11) housed in the cassette 6e is counted by detecting the peak value of the brightness of the reflected light by the sensor 6f. In addition, as the sensor 6f, a transmission type mapping sensor or a comb type mapping sensor can also be used.

[0040] Here, returning Figure 1 to the other structural elements of the cutting device 2 will be described. An opening 4b having a length portion in the X-axis direction is formed on the rear of the opening 4a. A table cover 10 in a flat plate shape is disposed in the opening 4b.

[0041] A corrugated dust and drip prevention cover 12 is disposed on both sides in the X-axis direction of the table cover 10. A ball screw type X-axis moving mechanism (machining feed unit) (not shown) is disposed below the table cover 10 and the dust and drip prevention cover 12.

[0042] A chuck table 14 is provided on the stage cover 10. The chuck table 14 is movable along the X-axis direction together with the stage cover 10 by an X-axis moving mechanism. A rotary drive source (not shown) such as a motor is connected to the lower portion of the chuck table 14, and the chuck table 14 is rotatable about a rotation axis substantially parallel to the Z-axis direction (vertical direction).

[0043] A disc-shaped porous plate formed of a porous ceramic is fixed to the upper portion of the chuck table 14. The porous plate is connected to a suction source (not shown) such as a vacuum pump via a prescribed flow path.

[0044] When the suction source is activated, a negative pressure is generated on the upper surface of the porous plate. Therefore, the upper surface of the chuck table 14 becomes a holding surface 14a that holds a wafer 11 or the like by suction. In addition, four clamps 14b for fixing the frame 19 from four sides are provided around the chuck table 14.

[0045] A pair of rails (not shown) substantially parallel to the Y-axis direction is disposed behind the opening 4a and above the opening 4b. The pair of rails adjusts the position of the wafer unit 21 taken out from the cassette 6e in the X-axis direction, for example.

[0046] A door-shaped support body 4c is provided on the side of the opening 4a and the pair of rails in the X-axis direction so as to cross the opening 4b. A lower arm unit (conveying unit) 16 that conveys the wafer unit 21 is provided on the side surface of the support body 4c on the other side in the X-axis direction.

[0047] The lower arm unit 16 is connected to a moving mechanism 16a. The moving mechanism 16a includes a rail substantially parallel to the Y-axis direction, and supports the lower arm unit 16 so as to be movable in the Y-axis direction.

[0048] The lower arm unit 16 has a cylinder 16b disposed along the Z-axis direction. A rod 16c that is movable up and down in the Z-axis direction by air pressure control is provided in the cylinder 16b.

[0049] The lower end of the rod 16c is connected to one end portion of a first arm portion 16d that is an elongated flat plate along the X-axis direction. An elongated flat plate-shaped second arm portion along the Y-axis direction is connected to the other end portion of the first arm portion 16d in the X-axis direction.

[0050] Wide portions having a length in the X-axis direction longer than a length in the Y-axis direction are provided at both end portions of the second arm portion in the Y-axis direction, and a plurality of adsorption pads 16e that can adsorb the frame 19 are provided on the lower surface side of each wide portion.

[0051] A holding mechanism 16f that holds the wafer unit 21 is provided on the side surface of the wide portion on the side opposite to the second arm portion on the front side. If the lower arm unit 16 is moved to the rear in a state where the holding mechanism 16f grips a portion of the frame 19, the wafer unit 21 housed in the cassette 6e can be pulled out to the pair of rails.

[0052] The wafer unit 21 whose position in the X-axis direction is adjusted by the pair of rails is carried onto the chuck table 14 from the pair of rails in a state where the frame 19 is adsorbed by the plurality of adsorption pads 16e by the lower arm unit 16.

[0053] On the other hand, in the case of carrying the wafer unit 21 to the cassette 6e, the wafer unit 21 is carried onto the pair of rails in a state where the frame 19 is adsorbed by the plurality of adsorption pads 16e.

[0054] Then, after the position of the wafer unit 21 in the X-axis direction is adjusted by the pair of rails, the lower arm unit 16 is moved to the front in a state where a portion of the frame 19 is gripped by the holding mechanism 16f, and the wafer unit 21 is pushed out from the pair of rails to the cassette 6e.

[0055] In addition, in the case of carrying the wafer unit 21 from the pair of rails to the wafer placement portion 6b, the height of the opening 6c is made substantially the same as the height of the pair of rails by the lifting mechanism 8, and then the wafer unit 21 is similarly pushed onto the wafer placement portion 6b.

[0056] In this way, the lower arm unit 16 carries the wafer unit 21 (wafer 11) between the cassette mechanism 6 (wafer placement portion 6b and cassette 6e) and the chuck table 14.

[0057] A door-shaped support body 4d is provided on the side opposite to the lower arm unit 16 with respect to the support body 4c so as to span the opening 4b. A pair of processing unit moving mechanisms (indexing feed unit, plunge feed unit) are provided on the side of the support body 4c in the support body 4d.

[0058] The pair of processing unit moving mechanisms have a pair of Y-axis rails (not shown) disposed on the front surface of the support body 4d and substantially parallel to the Y-axis direction. A Y-axis moving plate 18 that constitutes each processing unit moving mechanism is slidably mounted on the pair of Y-axis rails.

[0059] A nut portion (not shown) in which a Y-axis ball screw (not shown) substantially parallel to the Y-axis rail is rotatably linked is provided on the side of the support body 4d of the Y-axis moving plate 18.

[0060] A Y-axis pulse motor (not shown) is connected to one end of the Y-axis ball screw. If the Y-axis ball screw is rotated by the Y-axis pulse motor, the Y-axis moving plate 18 moves along the Y-axis guide rail in the Y-axis direction.

[0061] A Z-axis guide rail (not shown) that is approximately parallel to the Z-axis direction is provided on the surface of the support body 4c of the Y-axis moving plate 18. A Z-axis moving plate (not shown) is slidably mounted on the Z-axis guide rail.

[0062] A nut portion (not shown) is provided on the surface of the support body 4d side of the Z-axis moving plate, and a Z-axis ball screw (not shown) parallel to the Z-axis guide rail is rotatably connected to the nut portion.

[0063] A Z-axis pulse motor 20 is connected to the upper end of the Z-axis ball screw (not shown). If the Z-axis ball screw is rotated by the Z-axis pulse motor 20, the Z-axis moving plate moves along the Z-axis guide in the Z-axis direction.

[0064] A cutting unit 22 for cutting the wafer 11 is provided at the lower part of the Z-axis moving plate. In this embodiment, a cutting unit 22 is provided at the lower part of each of a pair of Z-axis moving plates. The pair of cutting units 22 are arranged opposite each other along the Y-axis direction.

[0065] Reference Figure 5 The cutting unit 22 will be described. The cutting unit 22 has a cylindrical spindle housing 22a whose length is arranged along the Y-axis direction. The spindle housing 22a can support a cylindrical spindle 22b, which serves as a rotation axis parallel to the Y-axis direction, so that it can rotate.

[0066] One end of the spindle 22b protrudes from the spindle housing 22a, and a cutting tool 22c with a ring-shaped cutting edge is mounted at this end. Additionally, a rotary drive source (not shown) such as an electric motor is connected to the other end of the spindle 22b.

[0067] like Figure 1 As shown, an imaging unit 24 for photographing the wafer 11 is provided adjacent to the cutting unit 22. The imaging unit 24 is a camera that includes imaging elements such as an objective lens and an image sensor, and is used for alignment of the wafer 11 with the cutting unit 22, etc.

[0068] A circular opening 4e is provided behind the opening 4b. A cleaning unit 26 for cleaning the wafer 11 after cutting is disposed in the opening 4e. The cleaning unit 26 includes: a rotary table that attracts and holds the wafer unit 21; and a nozzle that sprays a gas-liquid mixture towards the holding surface of the rotary table.

[0069] The wafer unit 21 is carried between the rotary table of the cleaning unit 26 and the chuck table 14 arranged at the opening 4b by the upper arm unit 30. The upper arm unit 30 is connected with a moving mechanism 30a.

[0070] The moving mechanism 30a includes a rail arranged above the moving mechanism 16a in the substantially parallel direction to the Y-axis direction to support the upper arm unit 30 so as to be movable in the Y-axis direction. The upper arm unit 30 has a cylinder 30b arranged in the Z-axis direction.

[0071] A rod 30c capable of moving up and down in the Z-axis direction by air pressure control is provided in the cylinder 30b. The lower end of the rod 30c is connected to the central portion of a first arm portion 30d which is an elongated flat plate in the X-axis direction.

[0072] Wide portions in the Y-axis direction having a length longer than that in the X-axis direction are provided at both ends of the first arm portion 30d in the X-axis direction, and a plurality of adsorption pads 30e capable of adsorbing the frame 19 are provided at the lower surface side of the wide portions.

[0073] The upper arm unit 30 carries the wafer unit 21 from the chuck table 14 to the rotary table of the cleaning unit 26 while adsorbing the frame 19 of the wafer unit 21 including the cut wafer 11 with the plurality of adsorption pads 30e.

[0074] The cutting device 2 also has a control unit 32 which controls the operation of each structural element. The control unit 32 controls the operation of the sensor 6f, the lifting mechanism 8, the X-axis moving mechanism, the processing unit moving mechanism, the lower arm unit 16, the cutting unit 22, the imaging unit 24, the cleaning unit 26, the upper arm unit 30, and the like.

[0075] The control unit 32 is constituted by, for example, a computer including a processing device such as a CPU (Central Processing Unit), a main storage device such as a DRAM (Dynamic Random Access Memory), a SRAM (Static Random Access Memory), a ROM (ReadOnly Memory), and an auxiliary storage device such as a flash memory, a hard disk drive, and a solid state drive.

[0076] A software including a prescribed program is stored in the auxiliary storage device. The function of the control unit 32 is realized by causing the processing device and the like to operate in accordance with the software. The control unit 32 has a determination section 34 constituted by a prescribed program. The determination section 34 determines the number of wafers 11 accommodated in the cassette 6e from the value of the peak of the brightness of the reflected light detected by the sensor 6f.

[0077] In addition, the determination unit 34 determines that the nth wafer 11 is carried out of the cassette 6e (i.e., carried out), and further determines that the nth wafer 11 is carried into the cassette 6e (i.e., carried in).

[0078] For example, the determination unit 34 determines that the nth wafer 11 is carried out of the cassette 6e in accordance with the number of times of operation of the lower arm unit 16 pulled out from the cassette 6e to the pair of rails. Similarly, the determination unit 34 determines that the nth wafer 11 is carried into the cassette 6e in accordance with the number of times of operation of the lower arm unit 16 pushed into the cassette 6e from the pair of rails.

[0079] The determination unit 34 determines that the wafer 11 last carried out of the cassette 6e is the final wafer 11 of the cassette 6e. In addition, in a case where all the wafers 11 except for the final wafer 11 are housed in the cassette 6e after cutting and cleaning, the control unit 32 generates a control signal for urging replacement of the cassette 6e.

[0080] The control unit 32 causes the touch panel 36 serving as an input device and a display device, a speaker (not shown), the alarm lamp 38, and the like, which are the notification unit 40, to operate in accordance with the control signal. For example, the control unit 32 causes the touch panel 36 to display a message such as "Please replace the cassette".

[0081] The control unit 32 can also play a sound such as "Please replace the cassette" or a prescribed alarm sound from the speaker instead of or together with the message display of the touch panel 36. In addition, the control unit 32 can also give a message urging replacement of the cassette 6e by causing the alarm lamp 38 to blink.

[0082] Next, the processing of the wafers 11 will be described with reference to Figures 4 to 7 A processing method of the plurality of wafers 11 will be described, which is performed after the plurality of wafers 11 are cut by the cutting unit 22 respectively. Figure 4 is a view for explaining the processing of the plurality of wafers 11 in time series.

[0083] As shown in Figure 4 , the operator places the first cassette 6e-1 (first cassette 6e-1) in which N wafer units 21 (i.e., wafers 11) are housed on the cassette placement table 6d (cassette placement step S10 of the first cassette 6e-1). In addition, N is a natural number of 2 or more, and in the present embodiment, N = 25.

[0084] When the first cassette 6e-1 is placed on the cassette placement table 6d, the lifting mechanism 8 is raised or lowered at a prescribed speed. At this time, the control unit 32 counts the number of wafer units 21 housed in the first cassette 6e-1 using the sensor 6f.

[0085] After the number of wafer units 21 is counted, the lower arm unit 16 carries the wafer 11 of #1 from the height position-adjusted first cassette 6e-1 to the chuck table 14 via a pair of rails (#1 wafer carrying step S20). Note that the symbol # indicates the order of the wafer 11 carried from the cassette 6e.

[0086] In the #1 wafer carrying step S20, the judging section 34 judges whether the carried wafer 11 is the final wafer 11 carried last from the first cassette 6e-1 (#1 judging step S30). Of course, the wafer 11 of #1 is not the final wafer 11.

[0087] After the #1 judging step S30, the chuck table 14 is moved downward of the cutting unit 22 in a state where the back surface 11b side of the wafer 11 of #1 is suction-held. Also, the orientation of the chuck table 14 is adjusted about the rotation axis so as to make the one division intended line 13 substantially parallel to the X-axis direction.

[0088] Then, in a state where the lower end of the high-speed rotating cutting tool 22c is positioned between the back surface 11b and the holding surface 14a, the cutting tool 22c and the chuck table 14 are relatively moved along the X-axis direction. Thereby, the wafer 11 is cut along the one division intended line 13 (#1 cutting step S40).

[0089] After the wafer 11 is cut along all the division intended lines 13, the suction of the chuck table 14 is released. Then, the upper arm unit 30 carries the wafer 11 of #1 from the chuck table 14 to the cleaning unit 26, and the cleaning unit 26 cleans the wafer 11 of #1 (#1 cleaning step S50).

[0090] When the wafer 11 of #1 is carried to the cleaning unit 26, the lower arm unit 16 carries the wafer 11 of #2 from the first cassette 6e-1 to the chuck table 14 via a pair of rails (#2 wafer carrying step S20). In this way, the lower arm unit 16 sequentially carries the wafer 11 from the cassette 6e.

[0091] Also, in the #2 wafer carrying step S20, the judging section 34 judges whether the carried wafer 11 is the final wafer 11 (#2 judging step S30). Of course, the wafer 11 of #2 is not the final wafer 11 either.

[0092] Further, the wafer 11 of #2 is cut by the cutting unit 22 (#2 cutting step S40). In this way, the cutting unit 22 sequentially cuts the wafer 11. Figure 5 is a view showing the case where the wafer 11 of #1 is cleaned and the wafer 11 of #2 is cut.

[0093] In Figure 5For convenience, "#1" is marked in the circle to represent chip 11 (i.e., chip unit 21) of number #1. Similarly, "#2" is marked in the circle to represent chip 11 (i.e., chip unit 21) of number #2.

[0094] During the cutting of wafer 11 of #2, the lower arm unit 16 transfers the cleaned wafer 11 of #1 from the rotary table to the first box 6e-1. Thus, wafer 11 of #1 is stored in the first box 6e-1 (box storage step S60 of #1).

[0095] After the #1 cassette storage step S60 is completed, the #2 cleaning step S50, the #3 wafer transfer step S20, and the #3 judgment step S30 are performed. Then, the #2 cassette storage step S60 and the #3 cutting step S40 are performed. In this way, each wafer 11 is processed sequentially.

[0096] Further processing is carried out, including the wafer transfer step S20 and the judgment step S30 of #N in the cleaning step S50 of #(N-1). Figure 6 This is a diagram showing the processing of wafer 11 of #(N-1) and wafer 11 of #N.

[0097] exist Figure 6 For convenience, "#(N-1)" is written in the long circle to represent the #(N-1) wafer 11 (i.e., wafer unit 21). Similarly, "#N" is written in the circle to represent the final wafer 11, i.e., the #N wafer 11 (i.e., wafer unit 21).

[0098] After the box storage step S60 of #(N-1) and the cutting step S40 of #N are completed, and all wafers 11 except for the wafer 11 of #N (i.e., the final wafer 11) are stored in the first box 6e-1, the operator is informed that the first box 6e-1 should be replaced. The operator accepts this instruction and, for example, manually removes the first box 6e-1 from the box mounting stage 6d and moves it to a designated stage located outside the cutting device 2.

[0099] Then, the operator places the second box 6e-2, which is different from the first box 6e-1, on the box placement stage 6d (box replacement step S70, i.e. box placement step S10 of the second box 6e-2). Figure 7 This is a diagram showing the box replacement step S70.

[0100] In the second box 6e-2, multiple chips 11 are also stored in the state of chip unit 21. After the box replacement step S70, the chip 11 of #1 is transferred from the second box 6e-2 to the chuck worktable 14 (transfer start step S80, i.e. chip transfer step S20 of #1).

[0101] As for each wafer 11 in the second cassette 6e-2, the processing is performed in the same order as the wafer 11 in the first cassette 6e-1. In Figure 7 In the circle, "#1" is written to indicate the wafer 11 (#1) of the second cassette 6e-2 (i.e., the wafer unit 21).

[0102] In addition, the final wafer 11 housed in the first cassette 6e-1 is conveyed to the wafer placement portion 6b after the wafer 11 of #1 of the second cassette 6e-2 is conveyed starting step S80, through the cutting step S40 of #N and the cleaning step S50 of #N.

[0103] The final wafer 11 is placed on the wafer placement portion 6b located below the second cassette 6e-2 by the lower arm unit 16, instead of being placed in the second cassette 6e-2 (final wafer placement step S90).

[0104] In addition, in the final wafer placement step S90, the final wafer 11 is conveyed to the wafer placement portion 6b in a state where the wafer placement portion 6b is raised to the same height as the pair of rails by the lifting mechanism 8.

[0105] In the present embodiment, the wafer 11 can be started to be conveyed from the second cassette 6e-2 to the chuck table 14 before the final wafer 11 is returned to the first cassette 6e-1. Therefore, compared to a case where the first cassette 6e-1 is replaced with the second cassette 6e-2 after all the wafers 11 housed are processed and conveyed into the first cassette 6e-1, the number of wafers 11 processed per unit time can be increased.

[0106] Further, the wafer placement portion 6b disposed on the lower side of the cassette placement stage 6d is raised and lowered together with the cassette placement stage 6d, so the movable range of the lower arm unit 16 is not changed, and the final wafer 11 can be placed on the wafer placement portion 6b by the lower arm unit 16. Therefore, there is an advantage that it is not necessary to change the movable range of the lower arm unit 16 with respect to the usual specifications as well.

[0107] After the final wafer placement step S90, the operator takes out the final wafer 11 placed on the wafer placement portion 6b from the wafer placement portion 6b by hand work, and houses it in the first cassette 6e-1 disposed outside the cutting apparatus 2 (take-out and housing step S100). Thereby, all the wafers 11 including the final wafer 11 can be housed in the first cassette 6e-1.

[0108] In addition to this, the configuration, method, and the like of the above-described embodiments can be appropriately changed and implemented within a range not departing from the object of the present application. The cassette replacement step S70 and the take-out and housing step S100 are not limited to the hand work of the operator, and can be performed by a conveyance robot (not shown).

Claims

1. A plurality of wafers processing method of housing a plurality of wafers each having a device formed in a plurality of regions divided by a plurality of division predetermined lines set on a front surface side in a cassette after cutting along each division predetermined line, characterized by comprising: a cassette placement step of placing a first cassette housing the plurality of wafers on a cassette placement table; a wafer conveyance step of sequentially conveying wafers from the first cassette to a chuck table; a judgment step of judging whether a wafer conveyed to the chuck table is a final wafer which is lastly conveyed from the first cassette; a cutting step of cutting wafers held by the chuck table sequentially by a cutting unit; a cleaning step of cleaning the wafers cut by the cutting step sequentially; a cassette housing step of housing a wafer which is not the final wafer in the first cassette after cutting the wafer by the cutting step and cleaning the wafer by the cleaning step; a cassette replacement step of replacing the first cassette from the cassette placement table after housing all the wafers except the final wafer in the first cassette and placing a second cassette housing a plurality of wafers and different from the first cassette on the cassette placement table; a conveyance start step of starting to convey a wafer from the second cassette to the chuck table after the cassette replacement step; and a final wafer placement step of placing the final wafer cut by the cutting step and cleaned by the cleaning step on a wafer placement portion provided on a lower side of the cassette placement table and raised and lowered together with the cassette placement table after the conveyance start step.

2. The plurality of wafers processing method according to claim 1, further comprising: a taking-out and housing step of taking out the final wafer placed on the wafer placement portion from the wafer placement portion and housing the final wafer in the first cassette after the final wafer placement step.

3. A cutting apparatus of housing a plurality of wafers each having a device formed in a plurality of regions divided by a plurality of division predetermined lines set on a front surface side in a cassette after cutting along each division predetermined line, characterized by comprising: a chuck table which holds a wafer; a cutting unit having a spindle and a cutting tool mounted on one end side of the spindle; a cleaning unit which cleans a wafer cut, the cleaning unit including a rotary table which holds a wafer by suction and a nozzle which sprays a fluid toward a holding surface of the rotary table; a cassette mechanism having a cassette placement table which places a first cassette housing a plurality of wafers and a wafer placement portion provided on a lower side of the cassette placement table and raised and lowered together with the cassette placement table; a conveyance unit which conveys a wafer between the cassette mechanism and the chuck table; a control unit including a judgment portion which judges a wafer lastly conveyed from the first cassette as a final wafer of the first cassette; and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The notification unit issues a message urging replacement of the first cassette when all the wafers other than the final wafer that were housed in the first cassette are housed in the first cassette after cutting by the cutting unit and cleaning by the cleaning unit, The control unit controls the conveyance unit to convey all the wafers other than the final wafer after cutting to the first cassette and the final wafer to the wafer placement portion, After all the wafers other than the final wafer are housed in the first cassette, and when a second cassette that houses a plurality of wafers and is different from the first cassette is placed on the cassette placement table, wafer conveyance from the second cassette to the chuck table is started before the final wafer after cutting and cleaning is placed on the wafer placement portion.

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