WAFER FABRICATION DEVICE

Abstract

A wafer manufacturing apparatus (2) that produces a wafer (252) from an ingot (230), the wafer manufacturing apparatus (2) comprising: an ingot grinding unit (4) comprising a first holding table (14) holding the ingot (230) and a grinding means (16) grinding an upper surface of the ingot (230) held by the first holding table (14) to planarize the upper surface; a laser irradiation unit (6) comprising a second holding table (60) holding the ingot (230) and laser irradiation means (62) that positions a focal point of a laser beam (LB) having a wavelength transmissible through the ingot (230) at a depth from the upper surface of the ingot (230) held by the second holding table (60) that corresponds to a thickness of a wafer (252) to be produced, and irradiates the ingot (230) with the laser beam (LB) to form a separation layer; a wafer separation unit (8) comprising a third holding table (80) holding the ingot (230) and a wafer separation means (82) that holds the upper surface of the ingot (230) held by the third holding table (80) and separates a wafer (252) from the separation layer; a tray (9) having an ingot support part (117) supporting the ingot (230) and a wafer support part (118) supporting the separated wafer (252); a conveyor belt unit (10) that transports the ingot (230) supported by the tray (9) between the ingot grinding unit (4), the laser irradiation unit (6) and the wafer separation unit (8); an ingot storage device (11) in which the ingot (230) supported by the support (9) is received; and an ingot supply unit (12) which supplies the ingot (230) to the conveyor unit (10) which is supported by the tray (9) which is received in the ingot storage device (11), the ingot supply unit (12) being arranged between the conveyor unit (10) and the ingot storage device (11).

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to a wafer manufacturing apparatus that manufactures wafers from an ingot. DESCRIPTION OF THE RELATED PRIOR ART

[0002] Devices such as an integrated circuit (IC), a large-scale integration (LSI), and a light-emitting diode (LED) are formed as follows. Specifically, a functional layer is deposited over a surface of a wafer made of silicon (Si), sapphire (Al 2 O 3) or the like, and the components are formed based on this functional layer in such a manner that they are demarcated by a plurality of intersecting planned division lines. Furthermore, a power device, an LED, etc. are formed as follows. Specifically, a functional layer is laid over a surface of a wafer whose material is silicon carbide single crystal (SiC single crystal), and these components are formed based on this functional layer in such a manner that they are demarcated by a plurality of intersecting planned division lines. The wafer over which components have been formed is divided into individual component chips by performing processing on the planned division lines by a cutter or a laser processing device, and the respective divided component chips are used for parts of electrical equipment such as mobile phones and personal computers.

[0003] The wafer over which the components are to be formed is generally manufactured by thinly slicing an ingot with a circular columnar shape using a wire saw. The front and back surfaces of the sliced ​​wafer are polished to a mirror finish (see, for example, Japanese Unexamined Patent Application Laid-Open No. 2000-94221A). However, when an ingot is sliced ​​using a wire saw and the front and back surfaces of the sliced ​​wafer are polished, a problem arises that most of the ingot (70% to 80%) becomes scrap, and this is uneconomical. Particularly in the case of a hexagonal SiC single-crystal ingot, the hardness is high, and cutting with a wire saw is difficult and time-consuming. Therefore, productivity is low. Furthermore, the unit cost of the ingot is high, and it is challenging to produce wafers efficiently.

[0004] For this reason, a technique has been proposed in which the focal point of a laser beam having such a wavelength that can be transmitted through a hexagonal SiC single crystal ingot is positioned inside a hexagonal SiC single crystal ingot, and the hexagonal SiC single crystal ingot is irradiated with the laser beam to form a separation layer on a predetermined cutting plane, and a wafer is separated from the hexagonal SiC single crystal ingot along the predetermined cutting plane at which the separation layer has been formed (see, for example, Japanese Patent Application Laid-Open No. 2013-49161 A).

[0005] Furthermore, the published patent application JP 2019-106458 A, as post-published prior art, discloses only a device for manufacturing components comprising an ingot polishing unit that polishes and planarizes an upper surface of an ingot, a laser beam application unit that applies a laser beam from the upper surface of the ingot and forms a release layer, a wafer release unit that holds the upper surface of the ingot and releases the wafer from the release layer, a wafer production device comprising an ingot support part that supports the ingot and a wafer support part that supports the peeled wafer, a belt conveyor unit that transports the ingot supported by the ingot polishing device between the ingot polishing device, the laser irradiation device, and the wafer peeling unit to the wafer production device, a cassette stacker in which a plurality of cassettes are accommodated,which receive the removed wafer, and a receiving device for receiving the wafer supported by the wafer production device into the cassette stacker. SUMMARY OF THE INVENTION

[0006] However, a step of forming a release layer in an ingot, a step of separating a wafer from the ingot, and a step of grinding the upper surface of the ingot to planarize the upper surface are carried out by labor, so that there is a problem of low manufacturing efficiency.

[0007] Accordingly, it is an object of the present invention to provide a wafer manufacturing apparatus that can automatically manufacture wafers from an ingot.

[0008] In accordance with one aspect of the present invention, a wafer manufacturing apparatus is provided that manufactures a wafer from an ingot.The wafer manufacturing apparatus includes an ingot grinding unit having a first holding table that holds the ingot and a grinding means that grinds an upper surface of the ingot held by the first holding table to planarize the upper surface; a laser irradiation unit having a second holding table that holds the ingot and a laser irradiation means that positions a focal point of a laser beam having such a wavelength that is transmissible through the ingot at a depth from the upper surface of the ingot held by the second holding table that corresponds to a thickness of a wafer to be manufactured and irradiates the ingot with the laser beam to form a separation layer; and a wafer separating unit having a third holding table that holds the ingot and a wafer separating means that holds the upper surface of the ingot held by the third holding table and separates a wafer from the separation layer.The wafer manufacturing apparatus also includes a tray having an ingot support part that supports the ingot and a wafer support part that supports the separated wafer, a conveyor unit that conveys the ingot supported by the tray between the ingot grinding unit, the laser irradiation unit, and the wafer separating unit, an ingot storage device in which the ingot supported by the tray is received, and an ingot supply unit that supplies the ingot supported by the tray, which is received in the ingot storage device, to the conveyor unit, the ingot supply unit being arranged between the conveyor unit and the ingot storage device.

[0009] Preferably, the ingot storage device includes a placing table on which the ingot supporting tray is placed, a first endless belt arranged in the placing table and leading out the ingot supporting tray, a driving force transmission part connected to the first endless belt and transmitting a driving force, and a frame in which a plurality of the placing tables are arranged in the vertical direction, and the ingot supply unit includes a receiving table that receives the ingot supporting tray from the placing table, a second endless belt arranged in the receiving table and feeding the ingot supporting tray to the conveyor belt unit, a motor that drives the second endless belt, a coupling part connected to the second endless belt and transmitting a driving force to the driving force transmission part, and an elevator.which positions the receiving table at any one of the plurality of placement tables arranged in the vertical direction. Preferably, the wafer manufacturing apparatus further includes a cassette storage device in which a plurality of cassettes containing the separated wafers are stored, and a receiving means for causing the wafer supported by the wafer support part of the tray to be received in the cassette stored in the cassette storage device.

[0010] According to the wafer manufacturing apparatus of the present invention, a series of works for manufacturing the wafers from the ingot can be automatically performed, and the manufacturing efficiency is improved.

[0011] The above and other objects, features and advantages of the present invention and the manner of carrying them into effect will become more apparent and the invention itself will be best understood by studying the following description and appended claims with reference to the attached drawings which show a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a wafer manufacturing apparatus of an embodiment of the present invention; Fig. 2 is a perspective view of a Fig. 1 shown ingot grinding unit; Fig. 3 is an enlarged perspective partial view of the Fig. 2 shown ingot grinding unit; Fig. 4 is a perspective view of a Fig. 1 laser irradiation unit; Fig. 5 is a block diagram of the Fig. 4 shown laser irradiation means; Fig. 6 is a perspective view of a Fig. 1 shown wafer separation unit; Fig. 7 is a partial sectional view of the Fig. 6 shown wafer separation unit; Fig. 8 is a perspective view of a Fig. 1 shown shelf; Fig. 9 is a partial perspective view of the Fig. 1 illustrated wafer manufacturing apparatus; Fig. 10A is a perspective view of a tray stopper in the state where a raising / lowering plate is arranged at a through position; Fig. 10B is a perspective view of the tray stopper in the state where the raising / lowering plate is arranged at a stop position; Fig. 10C is a perspective view of the tray stopper in the state where the raising / lowering plate is arranged at a separation position; Fig. 11A is a sectional view of the filing stopper, etc., which is connected to the Fig. 10A corresponds to the state shown; Fig. 11B is a sectional view of the filing stopper, etc., which is connected to the Fig. 10B corresponds to the state shown; Fig. 11C is a sectional view of the tray stopper, etc., which is connected to the Fig. 10C corresponds to the state shown; Fig. 12A is a perspective view of a conveyance in the state where a raising / lowering plate is arranged at a raised position; Fig. 12B is a perspective view of the conveyance in the state where the raising / lowering plate is arranged at a lowered position; Fig. 13 is a perspective view of a Fig. 1 shown ingot storage device; Fig. 14 is a perspective view of a Fig. 1 shown ingot supply unit; Fig. 15 is a perspective view of the state in which the Fig. 13 shown ingot storage device and the in Fig. 14 shown ingot supply unit; Fig. 16 is a perspective view showing a modified example of a coupling part; Fig. 17A is a front view of a hexagonal SiC single crystal ingot; Fig. Figure 17B is a top view of the hexagonal SiC single crystal ingot; Fig. Figure 17C is a perspective view of the hexagonal SiC single crystal ingot; Fig. 18 is a perspective view illustrating the state in which the ingot is conveyed to a second holding table of the laser irradiation unit; Fig. 19A is a perspective view illustrating the state in which a separation layer forming step is carried out; Fig. 19B is a front view illustrating the state in which the separation layer forming step is carried out; Fig. 20A is a plan view of the ingot in which a release layer is formed; Fig. 20B is a sectional view taken along line BB in Fig. 20A; Fig. 21A is a perspective view illustrating the state in which a liquid bath is arranged above a third holding table of the wafer separation unit; Fig. 21B is a perspective view illustrating the state in which the lower end of the liquid bath is in contact with the upper surface of the third holding table; and Fig. Fig. 22 is a perspective view illustrating the state in which a wafer is separated from the ingot by the wafer separating unit. DETAILED EXPLANATION OF THE PREFERRED EMBODIMENT

[0012] A wafer manufacturing apparatus of an embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is configured at least with an ingot grinding unit 4, a laser irradiation unit 6, a wafer separating unit 8, a tray 9 including an ingot support member that supports an ingot and a wafer support member that supports a separated wafer, a conveyor unit 10 that conveys the ingot supported by the tray 9 between the ingot grinding unit 4, the laser irradiation unit 6, and the wafer separating unit 8, an ingot stocker 11 that receives the ingot supported by the tray 9, and an ingot supply unit 12 that supplies the ingot supported by the tray 9, which is received in the ingot stocker 11, to the conveyor unit 10.

[0013] The ingot grinding unit 4 is described with reference to Fig. 2. The ingot grinding unit 4 is configured with at least a first holding table 14 that holds an ingot and has a circular shape, and an abrasive 16 that grinds the upper surface of an ingot held by the first holding table 14 to planarize the upper surface. The ingot grinding unit 4 of the present embodiment includes a base 18 having a rectangular parallelepiped shape and a circular rotary table 20 rotatably mounted on the upper surface of the base 18. The rotary table 20 is rotated by an unillustrated rotary table motor installed in the base 18, with the rotation center as an axis line passing through the center of the rotary table 20 in the radial direction and extending in a Z-axis direction.Furthermore, in the present embodiment, a pair of first holding tables 14 are rotatably mounted on the upper surface of the rotary table 20 and arranged with point symmetry, with the point of symmetry as the center of the rotary table 20 in the radial direction (rotation center). The first holding tables 14 are alternately mounted at a grinding position where grinding is performed by the abrasive 16 (rear position in FIG. Fig. 2) and an ingot attachment / removal position for attaching / removing an ingot (front position in Fig. 2) positioned by rotating the turntable 20.

[0014] The first holding table 14 is rotated by an unillustrated first holding table motor mounted on the lower surface of the rotary table 20, with the rotation center being an axis line passing through the radial center of the first holding table 14 and extending in the Z-axis direction. Furthermore, a porous suction chuck 22 connected to an unillustrated suction means is disposed on the upper surface of the first holding table 14. In the first holding table 14, an ingot placed on the upper surface of the suction chuck 22 is sucked and held by generating a suction force for the upper surface of the suction chuck 22 by the suction means. The Z-axis direction is the up-down direction, which is Fig. 2 is represented by an arrow Z. In addition, an X-axis direction, which is Fig. 2 is represented by an arrow X, a direction perpendicular to the Z-axis direction, and a Y-axis direction, which is Fig. 2, represented by an arrow Y, is a direction perpendicular to the X-axis direction and the Z-axis direction. The plane defined by the X-axis direction and the Y-axis direction is essentially horizontal.

[0015] As in Fig. 2, the grinding means 16 of the ingot grinding unit 4 in the present embodiment includes a gate-shaped support frame 24 mounted on the upper surface of the base 18. The support frame 24 has a pair of support columns 26 extending upward from the upper surface of the base 18 by a distance in the Y-axis direction, and a beam 28 spanning between the upper ends of the support columns 26 and extending in the Y-axis direction. A spindle housing 30 is movably supported (movable up and down) in the Z-axis direction by the pair of support columns 26 via a pair of links 32. A pair of raising and lowering motors 34 for causing the spindle housing 30 to move (move up and down) in the Z-axis direction are mounted on the upper surface of the beam 28.The lifting and lowering motor 34 is connected to a single end portion of an unillustrated ball screw extending inside the support column 26 in the Z-axis direction, and an unillustrated nut portion of the ball screw is fixed to the link 32. Furthermore, a rotational motion of the lifting and lowering motor 34 is converted into a linear motion by the ball screw and transmitted to the link 32, thereby lifting and lowering the spindle housing 30.

[0016] A spindle 36 (see Fig. 3) is supported by the spindle housing 30 for rotation about an axis extending in the Z-axis direction, and this spindle 36 is rotated about the axis extending in the Z-axis direction by an unillustrated spindle motor built into the spindle housing 30. A wheel holder 38 having a circular disk shape is attached to the lower end of the spindle 36, and an annular grinding wheel 42 is fixed by bolts 40 to the lower surface of the wheel holder 38. On the outer peripheral edge part of the lower surface of the grinding wheel 42, a plurality of abrasives 44 are arranged in a ring-like manner with intervals in the circumferential direction. When the first support table 14 is positioned at the grinding position, the center of rotation of the grinding wheel 42, as shown in Fig. 3, offset with respect to the center of rotation of the first holding table 14 in such a manner that the abrasives 44 pass through the center of rotation of the first holding table 14. For this reason, in the abrasive 16, the entire upper surface of an ingot can be planarized by grinding with the abrasives 44 by bringing the upper surface of the ingot held by the first holding table 14 into contact with the abrasives 44 while rotating the first holding table 14 and the grinding wheel 42 together.

[0017] The laser irradiation unit 6 is described with reference to the Fig. 1 to 4. As described in Fig. 1, the laser irradiation unit 6 arranged adjacent to the ingot grinding unit 4 is configured with at least a second holding table 60 which holds an ingot and has a circular shape, and a laser irradiation means 62 which positions the focal point of a laser beam having such a wavelength as to be transmitted through the ingot at a depth from the upper surface of the ingot held by the second holding table 60 that corresponds to the thickness of the wafer to be manufactured, and irradiates the ingot with the laser beam to form a separation layer.

[0018] As in Fig. 4, the laser irradiation unit 6 in the present embodiment includes a base 64 having a rectangular parallelepiped shape, and a mounting recess 64a recessed downward and extending in the X-axis direction is formed in the upper surface of this base 64. Furthermore, in the present embodiment, the second holding table 60 is mounted in the mounting recess 64a of the base 64 so as to be movable in the X-axis direction and rotatable about an axis line extending in the Z-axis direction. Furthermore, the base 64 is equipped with an unillustrated X-axis feed means that moves the second holding table 60 in the X-axis direction along the mounting recess 64a, and an unillustrated second holding table motor that rotates the second holding table 60 about an axis line passing in the radial direction through the center of the second holding table 60 and extending in the Z-axis direction.For example, it suffices for the X-axis feeding means to be a structure including a ball screw connected to the second holding table 60 and extending in the X-axis direction, and a motor that rotates this ball screw. The motor for the second holding table is moved in the X-axis direction by the X-axis feeding means together with the second holding table 60. Therefore, even when the second holding table 60 is moved in the X-axis direction by the X-axis feeding means, the motor for the second holding table rotates the second holding table 60. In addition, a porous suction chuck 66 connected to a suction means (not shown) is arranged on the upper surface of the second holding table 60. In the second holding table 60, an ingot placed on the upper surface of the suction chuck 66 is sucked and held by generating a suction force to the upper surface of the suction chuck 66 by the suction means.

[0019] As in Fig. As shown in FIG. 4, the laser irradiation means 62 of the laser irradiation unit 6 includes a gate-shaped support frame 68 mounted on the upper surface of the base 64, a casing 70 supported inside the support frame 68, an unillustrated Y-axis movable member mounted on the lower end side of the casing 70 for movement in the Y-axis direction, and an unillustrated Y-axis feed means that moves the Y-axis movable member in the Y-axis direction. For example, it suffices for the Y-axis feed means to be a structure including a ball screw connected to the Y-axis movable member and extending in the Y-axis direction, and a motor that rotates this ball screw.

[0020] Referring to Fig. 5 in conjunction with Fig. 4, the laser irradiation means 62 further includes a laser oscillator 72 (see Fig. 5) which is installed in the housing 70, a light collector or a condenser 74 (see Fig. 4 and Fig. 5) mounted on the lower end side of the Y-axis movable member so as to be movable up and down, an alignment means 76 (see Fig. 4) mounted on the lower end side of the Y-axis movable member in the Y-axis direction at a distance from the light collector 74, and an unillustrated focal point position adjusting means that raises and lowers the light collector 74 to adjust the position in the Z-axis direction with respect to the focal point of a pulsed laser beam LB converged by the light collector 74. The laser oscillator 72 oscillates a pulsed laser having a wavelength transmitted through the ingot, and the pulsed laser beam LB is emitted from the laser oscillator 72. The light collector 74 has an unillustrated converging lens that converges the pulsed laser beam LB emitted from the laser oscillator 72. The alignment means 76 images the ingot held by the second holding table 60 and detects the area to be subjected to laser processing.For example, it is sufficient for the focal point position adjusting means to be a structure including a ball screw connected to the light collector 74 and extending in the Z-axis direction, and a motor that rotates this ball screw.

[0021] As in Fig. 5, the following mirrors are installed in the housing 70: a first mirror 78 arranged at a distance from the laser oscillator 72 in the X-axis direction and reflecting the pulsed laser beam LB emitted from the laser oscillator 72, arranged with the optical axis along the X-axis direction to change the direction of the optical axis to the Y-axis direction; and a second mirror (not shown) arranged above the light collector 74 at a distance from the first mirror 78 in the Y-axis direction and changing the direction of the optical path of the pulsed laser beam LB reflected by the first mirror 78 from the Y-axis direction to the Z-axis direction to guide the pulsed laser beam LB to the light collector 74.

[0022] The second mirror is mounted on the Y-axis movable member and moves in the Y-axis direction together with the light collector 74 and the alignment means 76 when the Y-axis movable member is moved by the Y-axis feeding means. Furthermore, the pulsed laser beam LB emitted from the laser oscillator 72 is adjusted with the optical path along the X-axis direction, subjected to a change in the optical path direction from the X-axis direction to the Y-axis direction by the first mirror 78, and guided to the second mirror. Subsequently, the direction of the optical path is changed from the Y-axis direction to the Z-axis direction by the second mirror, and the pulsed laser beam LB is guided to the light collector 74. Then, the pulsed laser beam LB is converged by the converging lens of the light collector 74 and applied to the ingot held by the second holding table 60.Moreover, even when the light collector 74 is moved in the Y-axis direction by movement of the Y-axis movable member by the Y-axis feeding means, and even when the light collector 74 is raised or lowered by the focal point position adjusting means, the pulsed laser beam LB emitted from the laser oscillator 72 in parallel to the X-axis direction is subjected to a change in the direction of the optical path from the X-axis direction to the Y-axis direction by the first mirror 78 and is guided to the second mirror, and the pulsed laser beam LB guided to the second mirror is subjected to a change in the direction of the optical path from the Y-axis direction to the Z-axis direction by the second mirror and is guided to the light collector 74.

[0023] Furthermore, at the laser irradiation means 62, the ingot held by the second holding table 60 is imaged by the alignment means 76, and the area to be subjected to laser processing is detected. Then, the light collector 74 is raised and lowered by the focal point position adjusting means, and the focal point of the pulsed laser beam LB having such a wavelength that is transmitted through the ingot is positioned at a depth from the upper surface of the ingot held by the second holding table 60 that corresponds to the thickness of the wafer to be manufactured. Thereafter, the ingot held by the second holding table 60 is irradiated with the pulsed laser beam LB while the light collector 74 is appropriately moved in the Y-axis direction by the Y-axis feeding means. Thereby, a separation layer in which the strength is reduced can be formed inside the ingot.When the ingot held by the second holding table 60 is irradiated with the pulsed laser beam LB, the second holding table 60 can be moved in the X-axis direction by the X-axis feeding means.

[0024] The wafer separation unit 8 is described with reference to Fig. 1 and Fig. 6. As described in Fig. 1, the wafer separation unit 8 arranged next to the laser irradiation unit 6 is constructed with at least a third holding table 80 which holds an ingot and has a circular shape, and a wafer separation means 82 which holds the upper surface of the ingot held by the third holding table 80 and separates a wafer from a separation layer.

[0025] As in Fig. 6, the wafer separating unit 8 in the present embodiment includes a base 84 having a rectangular parallelepiped shape, and a mounting recess 84a recessed downward and extending in the X-axis direction is formed in the upper surface of this base 84. Moreover, in the present embodiment, the third holding table 80 is mounted in the mounting recess 84a of the base 84 so as to be movable in the X-axis direction. Furthermore, the base 84 is provided with an X-axis feeding means (not shown) that moves the third holding table 80 along the mounting recess 84a in the X-axis direction. For example, it suffices for the X-axis feeding means to be a structure including a ball screw connected to the third holding table 80 and extending in the X-axis direction, and a motor that rotates this ball screw.In addition, a porous suction chuck 86 connected to a suction means (not shown) is disposed on the upper surface of the third holding table 80. In the third holding table 80, an ingot placed on the upper surface of the suction chuck 86 is sucked and held by the suction means applying suction to the upper surface of the suction chuck 86.

[0026] As in Fig. As shown in FIG. 6, the wafer separating means 82 of the wafer separating unit 8 includes a gate-shaped support frame 88 mounted on the upper surface of the base 84, a housing 90 supported inside the support frame 88, an arm 92 extending upward and downward in the X-axis direction from a base end portion supported by the housing 90, and an unillustrated arm moving means that raises and lowers the arm 92. For example, it suffices for the arm moving means to be a structure including a ball screw connected to the base end portion of the arm 92 and extending in the Z-axis direction, and a motor that rotates this ball screw.

[0027] The description about the wafer separating means 82 will be made with reference to the Fig. 7 in conjunction with Fig. 6. As in Fig. 6 and Fig. As shown in Fig. 7, a liquid bath 94 is attached to the front part of the arm 92, which, in cooperation with the third holding table 80, contains a liquid when separating a wafer from an ingot. The liquid bath 94 has a circular upper wall 96 and a skirt wall 98 that descends from the peripheral edge of the upper wall 96 and has a circular cylindrical shape, and whose lower end is open. The outer diameter of the skirt wall 98 is set equal to or smaller than the diameter of the third holding table 80, and the lower end of the skirt wall 98 comes into contact with the upper surface of the third holding table 80 when the arm 92 is lowered.A liquid supply part 100, which allows the outside and inside of the liquid bath 94 to communicate with each other and has a circular cylindrical shape, is provided on the upper wall 96, and the liquid supply part 100 is connected to a liquid supply means (not shown). As shown in FIG. Fig. 7, an annular seal 102 is attached to the lower end of the skirt wall 98. Moreover, when the arm 92 is lowered by the arm moving means to bring the lower end of the skirt wall 98 into close contact with the upper surface of the third holding table 80, a liquid housing space 104 is defined by the upper surface of the third holding table 80 and the inner surface of the liquid bath 94. A liquid 106 supplied from the liquid supplying means to the liquid receiving space 104 through the liquid supplying part 100 is prevented from leaking out of the liquid receiving space 104 by the seal 102.

[0028] As in Fig. As shown in Fig. 7, an air cylinder 108 is mounted on the upper wall 96 of the liquid bath 94, and a cylinder tube 108a of the air cylinder 108 extends upward from the upper surface of the upper wall 96. A lower end portion of a piston rod 108b of the air cylinder 108 passes through a through hole 96a of the upper wall 96 and protrudes to the lower side of the upper wall 96. An ultrasonic vibration generating element 110, which may be formed of piezoelectric ceramics or the like, is fixed to the lower end portion of the piston rod 108b, and a suction attachment piece 112 is fixed to the lower surface of the ultrasonic vibration generating element 110. The suction attachment piece 112, which has a plurality of unillustrated suction holes formed in the lower surface, is connected to an unillustrated suction means.By generating a suction force for the lower surface of the suction piece 112 by the suction means, the suction piece 112 sucks and holds an ingot.

[0029] Furthermore, in the wafer separating means 82, the arm 92 is lowered by the arm moving means, and the lower end of the skirt wall 98 is brought into close contact with the upper surface of the third holding table 80 holding an ingot in which a separation layer has been formed. Furthermore, the piston rod 108b of the air cylinder 108 is lowered, and the suction adhesion piece 112 is caused to adhere to the upper surface of the ingot by negative pressure. Thereafter, the liquid 106 is received in the liquid receiving space 104, and then the ultrasonic vibration generating element 110 is actuated to apply ultrasonic vibration to the ingot. This can further reduce the strength of the separation layer.Moreover, in the wafer separating means 82, a wafer can be separated from the ingot by lifting the suction adhesion piece 112 by the air cylinder 108 in the state where the upper surface of the ingot is caused to adhere to the suction adhesion piece 112 by a negative pressure, by using the separation layer whose strength has been further reduced as a starting point.

[0030] File 9 is opened with reference to Fig. 8. The tray 9 of the present embodiment is constructed with a rectangular upper wall 113, a rectangular lower wall 114 disposed below the upper wall 113, a pair of rectangular side walls 115 coupling the upper wall 113 and the lower wall 114, and a cavity 116 extending between the pair of side walls 115. The tray 9 has an ingot support portion 117 supporting an ingot in the upper surface of the upper wall 113 and a wafer support portion 118 supporting a cut wafer in the upper surface of the lower wall 114.

[0031] The ingot support part 117 of the present embodiment has a recessed part 119 corresponding to ingots of two or more sizes. The recessed part 119 includes an annular larger-diameter recessed part 119a recessed downward from the upper surface of the upper wall 113, and a circular smaller-diameter recessed part 119b having a smaller diameter than the larger-diameter recessed part 119a and recessed further downward relative to the larger-diameter recessed part 119a. The larger-diameter recessed part 119a and the smaller-diameter recessed part 119b are concentrically formed.Furthermore, in the tray 9, an ingot having a comparatively large diameter (for example, a diameter of 6 inches) is supported by the larger diameter recess part 119a, and an ingot having a comparatively small diameter (for example, a diameter of 5 inches) is supported by the smaller diameter recess part 119b.

[0032] Although a detailed schematic representation has been omitted, the wafer support part 118 has a recess part 120 corresponding to wafers of two or more sizes. The structure of the recess part 120 of the wafer support part 118 may be a structure including a larger-diameter annular recess part recessed downward from the upper surface of the bottom wall 114 and a smaller-diameter circular recess part having a smaller diameter than the larger-diameter recess part and recessed further downward relative to the larger-diameter recess part, similar to the structure of the recess part 119 of the ingot support part 117. The larger-diameter recess part and the smaller-diameter recess part of the wafer support part 118 may be formed concentrically.Furthermore, in the tray 9, a wafer with a comparatively large diameter (for example, a 6-inch diameter) is supported by the larger-diameter recess portion of the wafer support member 118, and a wafer with a comparatively small diameter (for example, a 5-inch diameter) is supported by the smaller-diameter recess portion of the wafer support member 118. Unlike the present embodiment, the tray 9 may have a structure including the wafer support portion in the upper surface of the upper wall 113 and the ingot support portion in the upper surface of the lower wall 114.

[0033] The conveyor belt unit 10 is described with reference to Fig. 9. The conveyor belt unit 10, which is arranged along the ingot grinding unit 4, the laser irradiation unit 6 and the wafer separating unit 8, is provided with at least one forward conveyor belt 121, which conveys the tray 9 in the direction indicated by an arrow Y1 in Fig. 9, a reverse-running conveyor belt 122, which transports the tray 9 in the direction indicated by an arrow Y2 in Fig. 9 shown direction Y2 (opposite direction to Y1), and a conveying means 123 which conveys the tray 9 from the end point of the forward-moving conveyor belt 121 to the start point of the reverse-moving conveyor belt 122.

[0034] The forward conveyor belt 121 includes a pair of support walls 125 extending in the Y-axis direction, with an internal plurality of rollers or rolls 126 in the X-axis direction rotatably mounted on the inner surface of each support wall 125 at intervals in the Y-axis direction, a pair of endless belts 127 wound around the rolls 126, and a motor 128 that rotates the rolls 126. In the present embodiment, three forward conveyor belts 121 are arranged along the Y-axis direction. However, the length of the conveyance path of the tray 9 can be appropriately changed by changing the number of forward conveyor belts 121 and the length of the support walls 125 in the Y-axis direction. In addition, in the forward conveyor belt 121, the tray 9 attached to the endless belts 127 is conveyed by the rollers 126 in the direction Y1 by rotating the endless belts 127 via the motor 128.

[0035] As in Fig. 9, the structure of the reverse conveyor belt 122, which is arranged below the forward conveyor belt 121, may be substantially the same as the structure of the forward conveyor belt 121 in the present embodiment. Accordingly, the structure of the reverse conveyor belt 122 has been given the same reference numerals as the structure of the forward conveyor belt 121. In addition, in the reverse conveyor belt 122, the tray 9 attached to the endless belts 127 is conveyed over the rollers 126 in the opposite direction to the forward conveyor belt 121 in the Y2 direction by rotating the endless belts 127 by the motor 128. The reverse conveyor belt 122 may be arranged above the forward conveyor belt 121. In addition, it is preferable that both the forward conveyor belt 121 and the reverse conveyor belt 122 always run when the wafer manufacturing apparatus 2 is running.

[0036] As in Fig. 9, a tray stopper 129, which stops the tray 9 conveyed by the forward conveyor belt 121, is arranged at both a position opposite to the ingot grinding unit 4 and a position opposite to the laser irradiation unit 6 on the forward conveyor belt 121. As shown in Fig. 10, the storage stopper 129 in the present embodiment includes a substrate 130 fixed by an unillustrated suitable clamp, a raising / lowering plate 131 movably supported up and down by the upper surface of the substrate 130, a cylinder means 132 that raises and lowers the raising / lowering plate 131, and a stopper piece 133 fixed to the end part of the raising / lowering plate 131 on the downstream side in the direction Y1.

[0037] As in the Fig. 10A to 10C, a pair of engagement projections 131a are formed on the upper surface of the raising / lowering plate 131, which engage with a pair of engagement recesses (not shown) formed in the lower surface of the lower wall 114 of the tray 9. As shown in FIGS. Fig. 10A to Fig. 11C, the cylinder means 132, which is air-operated or electrically operated, positions the raising / lowering plate 131 at the following positions: a through position (for example, the position shown in the Fig. 10A and Fig. 11A) in which the upper end of the stopper piece 133 is located on the lower side relative to the lower end of the tray 9 conveyed by the forward conveyor belt 121; a stop position (for example, the position shown in Fig. 10B and Fig. 11B) in which the stopper piece 133 comes into contact with the tray 9 being conveyed by the forward-moving conveyor belt 121; and a separating position (for example, the position shown in Fig. 10C and Fig. 11C), via which the tray 9 is separated from the endless belts 127.

[0038] In addition, in the tray stopper 129, the passing of the tray 9 over the tray stopper 129 is prevented by positioning the raising / lowering plate 131 at the passing position (see Fig. 11A), and the tray 9 conveyed by the forward conveyor belt 121 can be moved by positioning the raising / lowering plate 131 at the stop position on the upper side relative to the passing position (see Fig. 11B). Furthermore, in the tray stopper 129, by positioning the raising / lowering plate 131 at the separation position on the upper side relative to the stop position, the load on the motor 128 of the forward conveyor belt 121 is prevented from increasing due to a displacement between the lower surface of the stopped tray 9 and the upper surfaces of the endless belts 127 (see Fig. 11C). In addition, positional displacement of the tray 9 at the raising / lowering plate 131 is prevented when the engaging projections 131a of the raising / lowering plate 131 engage with the engaging recesses of the tray 9 at the stop position or the separating position.

[0039] The means of transport 123 is described with reference to the Fig. 9, Fig. 12A and Fig. 12B. The conveying means 123, which is arranged adjacent to the end point of the forward conveyor belt 121 and the start point of the reverse conveyor belt 122, includes a support wall 134 extending in the Z-axis direction, a lifting / lowering plate 135 movably supported up and down by the support wall 134, a lifting / lowering means 136 that lifts and lowers the lifting / lowering plate 135, a Y-axis movable plate 137 supported by the upper surface of the Y-axis movable lifting / lowering plate 135, a Y-axis feeding means (not shown) that moves the Y-axis movable plate 137 in the Y-axis direction, and a stopper piece 138 provided at the end part of the in the Y-axis direction movable plate 137 is fixed on the downstream side in the direction Y1.

[0040] The raising / lowering means 136 includes a ball screw 139 connected to the raising / lowering plate 135 and extending in the Z-axis direction, and a motor 140 that rotates the ball screw 139. The raising / lowering means 136 raises and lowers the raising / lowering plate 135 in the Z-axis direction along guide rails 134a of the support wall 134 and stops the raising / lowering plate 135 at any position between a Fig. 12A and a raised position shown in Fig. 12B. On the upper surface of the Y-axis movable plate 137, a pair of engaging projections 137a are formed, which engage with the above-described pair of engaging recesses of the tray 9. The Y-axis feeding means is formed with, for example, an air cylinder or an electric cylinder, and moves the Y-axis movable plate 137 in the Y-axis direction along guide rails 135a of the raising / lowering plate 135 between an advanced position shown in the Fig. 12A and Fig. 12B is represented by a double-dotted line, and a retracted position shown in the Fig. 12A and Fig. 12B is represented by solid lines.

[0041] Furthermore, by positioning the upper surface of the Y-axis movable plate 137 on the slightly lower side relative to the upper surfaces of the endless belts 127 of the advancing conveyor belt 121 and by positioning the Y-axis movable plate 137 at the extended position, the stopper piece 138 in the conveying means 123 can be brought into contact with the tray 9 conveyed by the advancing conveyor belt 121, and the tray 9 can be stopped at the end point of the advancing conveyor belt 121 (also the position opposite to the wafer separating unit 8 in the present embodiment). In addition, by raising the raising / lowering plate 135 in the state where the tray 9 is standing orhas been stopped, the lower surface of the tray 9 can be separated from the upper surfaces of the endless belts 127, and the tray 9 can be attached to the upper surface of the Y-axis movable plate 137. When the tray 9 is attached to the Y-axis movable plate 137, the engaging projections 137a of the Y-axis movable plate 137 are engaged with the engaging recesses of the tray 9, and positional displacement of the tray 9 with the Y-axis movable plate 137 is prevented. Moreover, the Y-axis movable plate 137 to which the tray 9 is attached is positioned at the retracted position, and the raising / lowering plate 135 is subsequently lowered until the upper surface of the Y-axis movable plate 137 is located on the slightly upper side relative to the upper surface of the endless belts 127 of the reverse conveyor belt 122.Subsequently, the Y-axis movable plate 137 is positioned at the feed position, and then the raising / lowering plate 135 is slightly lowered. This allows the tray 9 to be transferred from the Y-axis movable plate 137 to the endless belts 127 of the reverse conveyor belt 122. In this way, the conveying means 123 conveys the tray 9 from the end point of the forward conveyor belt 121 to the start point of the reverse conveyor belt 122.

[0042] As in Fig. 9, the conveyor unit 10 in the present embodiment further includes a first transfer means 141 that transfers an ingot between the tray 9 stopped by the tray stopper 129 on the start point side of the forward conveyor belt 121 and the ingot grinding unit 4, a second transfer means 142 that transfers an ingot between the tray 9 stopped by the tray stopper 129 on the end point side of the forward conveyor belt 121 and the laser irradiation unit 6, and a third transfer means 143 that transfers an ingot between the tray 9 stopped by the transfer means 123 and the wafer separating unit 8 and transfers a wafer that has been separated from an ingot by the wafer separating unit 8 to the tray 9.

[0043] The structure of the second transfer means 142 and the structure of the third transfer means 143 may be the same as the structure of the first transfer means 141. Therefore, the structure of the first transfer means 141 will be described below, while a description of the structure of the second transfer means 142 and the structure of the third transfer means 143 will be omitted. The first transfer means 141 includes a multi-joint arm 144, an unillustrated drive source that drives the multi-joint arm 144, and a suction pad 145 attached to the end of the multi-joint arm 144. The drive source, which is configured with an air drive source or an electric drive source, drives the multi-joint arm 144 to position the suction pad 145 at an arbitrary position in any direction of the X-axis direction, the Y-axis direction, and the Z-axis direction, and to invert the suction pad 145.The suction adhesion piece 145, which has a plurality of suction holes (not shown) formed in a single surface, is connected to a suction means (not shown). In the first transfer means 141, an ingot is sucked and held via the suction adhesion piece 145 by generating a suction force for the suction adhesion piece 145 by the suction means. Furthermore, in the first transfer means 141, the ingot, which has been made to adhere to the suction adhesion piece 145 by a negative pressure, is transferred between the tray 9, which has been stopped by the tray stopper 129, and the ingot grinding unit 4 by driving the multi-joint arm 144 by means of the drive source.

[0044] The ingot storage device 11 is described with reference to Fig. 13. The ingot storage device 11 of the present embodiment is configured with at least placement tables 146 on which the tray 9 supporting an ingot is placed, first endless belts 148 disposed in the placement tables 146 and leading out the tray 9 supporting an ingot, driving force transmission parts 150 connected to the first endless belts 148 and transmitting a driving force, and a frame 152 in which a plurality of placement tables 146 are arranged in the vertical direction.

[0045] As in Fig. As shown in Fig. 13, a rectangular opening 154 extending in the Y-axis direction is formed in the upper surface of the placement table 146 having a rectangular shape, and a plurality of rollers (not shown) are rotatably mounted on the placement table 146. The first endless belt 148 is wound around the plurality of rollers of the placement table 146, and the upper surface of the first endless belt 148 is exposed through the rectangular opening 154. In addition, the driving force transmission member 150 extending in the X-axis direction and having a circular cylindrical shape is rotatably mounted on the placement table 146. One end part of the driving force transmission part 150 protrudes from a side surface on one end side of the placement table 146 in the Y-axis direction, and the other end part of the driving force transmission part 150 is connected to the roller around which the first endless belt 148 is wound.The rack 152 of the present embodiment includes a pair of side plates 156 arranged at a pitch in the X-axis direction, and four shelves 158 arranged at pitches in the up-down direction between the side plates 156, and a placement table 146 is arranged on each shelf 158. Moreover, when the driving force transmission member 150 in the ingot storage device 11 is rotated, the first endless belt 148 rotates, and the tray 9 placed on the upper surface of the placement table 146 is fed out in the Y-axis direction by the first endless belt 148. The roller of the placement table 146 may be formed with a circular cylindrical member and double as the driving force transmission member 150.

[0046] The ingot supply unit 12 is described with reference to Fig. 1 and Fig. 14. As described in Fig. 1, the ingot supply unit 12 is arranged between the conveyor belt unit 10 and the ingot storage device 11. Furthermore, the ingot supply unit 12 of the present embodiment, as shown in Fig. 14, at least a receiving table 160 that receives the tray 9 from the placing table 146 that supports an ingot, a second endless belt 162 that feeds the tray 9, which is arranged on the receiving table 160 and supports an ingot, to the conveyor belt unit 10, a motor 164 that drives the second endless belt 162, a coupling part 166 that is connected to the second endless belt 162 and transmits a driving force to the driving force transmission part 150 of the ingot storage device 11, and an elevator 168 that positions the receiving table 160 at one of the plurality of placing tables 146 arranged in the vertical direction.

[0047] As in Fig. As shown in Fig. 14, a pair of rectangular openings 170 extending in the Y-axis direction by a pitch in the X-axis direction are formed in the upper surface of the receiving table 160 having a rectangular shape, and a plurality of unillustrated rollers are rotatably mounted on the receiving table 160. The second endless belts 162 are wound around a plurality of rollers of the receiving table 160, and the upper surfaces of the second endless belts 162 are exposed through the rectangular openings 170. In addition, a driving force transmission member 172 extending in the X-axis direction and having a circular cylindrical shape is rotatably mounted in the Y-axis direction on one end side of the receiving table 160. One end part of the driving force transmission part 172 protrudes from a side surface of the receiving table 160, and the other end part of the driving force transmission part 172 is connected to the roller around which the second endless belt 162 is wound.The motor 164 is mounted on the side surface of the receiving table 160 on the other end side in the Y-axis direction, and an unillustrated shaft of the motor 164 is connected to the roller around which the second endless belt 162 is wound. The roller of the receiving table 160 may be formed with a circular cylindrical member and double as the driving force transmission part 172.

[0048] The description is made with reference to Fig. 14. The coupling part 166 includes an air cylinder 174 having a cylinder tube 174a fixed to the receiving table 160 and a piston rod 174b mounted on the cylinder tube 174a for forward and backward movement in the X-axis direction, a clamp piece 176 fixed to the end of the piston rod 174b of the air cylinder 174, a pair of tapered pins 178 rotatably mounted on the clamp piece 176 at a pitch in the Y-axis direction, and an endless drive belt 180 wound around the pair of tapered pins 178. In addition, the elevator 168 includes a substrate 182, a support plate 184 extending from an end part of the substrate 182 in the X-axis direction in the Z-axis direction, a lifting / lowering plate 186 supported by the support plate 184 to be movable up and down, and a lifting / lowering means 188 that lifts and lowers the lifting / lowering plate 186.The receiving table 160 is arranged on the upper surface of the raising / lowering plate 186. The raising / lowering means 188 includes a ball screw (not shown) connected to the raising / lowering plate 186 and extending in the Z-axis direction, and a motor 190 that rotates this ball screw. The raising / lowering means 188 raises and lowers the raising / lowering plate 186 in the Z-axis direction along guide rails 184a of the support plate 184, and stops the raising / lowering plate 186 at an arbitrary position.

[0049] Referring to Fig. 15, in the ingot supply unit 12, the raising / lowering plate 186 of the elevator 168 is raised and lowered, and the raising / lowering plate 186 is stopped at a position where the upper surface of the arbitrary placing table 146 of the ingot storage device 11 and the upper surface of the receiving table 160 are arranged at the same height. Thereafter, the piston rod 174b of the air cylinder 174 of the coupling part 166 is rotated by a Fig. 15 to a retracted position. Due to this, one of the pair of tapered pins 178 of the coupling part 166 is inserted into the driving force transmission part 150 of the ingot storage device 11 and is connected in such a manner as to be capable of transmitting rotation. Furthermore, the other of the pair of tapered pins 178 is inserted into the driving force transmission part 172 of the ingot supply unit 12 and is connected in such a manner as to be capable of transmitting rotation. When the motor 164 rotates in this state, the second endless belts 162 rotate. In addition, the first endless belt 148 of the ingot storage device 11 rotates by rotation of the driving force transmission part 172, the pair of tapered pins 178 and the drive belt 180 of the ingot supply unit 12 and the driving force transmission part 150 of the ingot storage device 11.Thereby, the tray 9 placed on the upper surface of the placing table 146 of the ingot storage device 11 is fed out in the Y-axis direction by the first endless belt 148 and is fed to the receiving table 160 of the ingot supply unit 12.

[0050] Furthermore, after the tray 9 is received by the receiving table 160, the ingot supply unit 12 stops the rotation of the motor 164 and moves the piston rod 174b of the air cylinder 174 of the coupling part 166 from the retracted position to the extended position. This releases the connection between one of the pair of tapered pins 178 and the driving force transmission part 150 of the ingot storage device 11 and releases the connection between the other of the pair of tapered pins 178 and the driving force transmission part 172 of the ingot supply unit 12. Then, the ingot supply unit 12 adjusts the upper surface of the receiving table 160 on which the tray 9 is placed to the same height as the upper surface of the endless belts 127 of the forward conveyor belt 121 of the conveyor belt unit 10 by raising and lowering the raising / lowering plate 186 by means of the elevator 168 as required, and then rotates the motor 164.As a result, the second endless belts 162 rotate, and the tray 9 placed on the upper surface of the receiving table 160 is fed to the forward conveyor belt 121 of the conveyor belt unit 10. In this way, the ingot supply unit 12 feeds the ingot, supported by the tray 9 accommodated in the ingot storage device 11, to the conveyor belt unit 10.

[0051] The driving force transmission part 150 of the ingot storage device 11 and the driving force transmission part 172 and the coupling part 166 of the ingot supply unit 12 are not limited to the embodiment described above and may, for example, have another embodiment such as that shown in Fig. 16. In the case of Fig. In the other embodiment shown in Figure 16, instead of the pair of tapered pins 178 of the coupling member 166 described above, a shaft 192 connected to the roller of the receiving table 160 and a drive magnet member 194 are rotatably mounted on a bracket piece 176. Furthermore, a drive magnet member 196 is mounted as a drive force transmission member on the roller of the placement table 146.

[0052] In addition, after the raising / lowering plate 186 has been moved to a position where the upper surface of the arbitrary placing table 146 of the ingot storage device 11 and the upper surface of the receiving table 160 are arranged at the same height, rotation of the motor 164 is stopped at the speed shown in Fig. 16, the force is transmitted to the first endless belt 148 of the placement table 146 via a magnetic coupling formed with the drive magnet element 194 and the drive magnet element 196. Since the magnetic coupling described above can be contact-free (a gap can be provided between the drive magnet element 194 and the drive magnet element 196), in the embodiment shown in Fig. 16, no air cylinder 174 is necessary to move the clamp piece 176 in the X-axis direction.

[0053] Referring to Fig. 1 and Fig. 9, the wafer manufacturing apparatus 2 of the present embodiment further includes a cassette storage device 200 in which a plurality of cassettes 198 accommodating separated wafers are accommodated, and a receiving means 202 that causes a wafer supported by the wafer support member 118 of the tray 9 to be accommodated in the cassette 198 accommodated in the cassette storage device 200.

[0054] As in Fig. 1, the cassette storage device 200 has a total of 16 cassette receiving parts 204 on four columns in the X-axis direction and four stages in the Z-axis direction. In each cassette receiving part 204, a cassette 198 is received, which receives wafers separated from an ingot in the wafer separation unit 8. The cassette 198 can receive a plurality (for example, 25) wafers at intervals in the up-down direction. In addition, each cassette receiving part 204 is received in the Y-axis direction in the cassette storage device 200. The cassette 198 can be arranged in the direction opposite to the Y-axis direction in Fig. 1 from the front side in each cassette receiving part 204, and a wafer can be loaded from the Y-axis direction into Fig. 1 rear side in the cassette receiving part 204.

[0055] As in Fig. 9, the receiving means 202 is arranged next to the ingot supply unit 12 and the cassette storage device 200. The receiving means 202 includes a support wall 206, an X-axis movable member 208 supported by the support wall 206 to be movable in the X-axis direction, an X-axis feed means 210 that moves the X-axis movable member 208 in the X-axis direction, a lifting / lowering block 212 supported by the X-axis movable member 208 to be movable up and down, a lifting / lowering means 214 that lifts and lowers the lifting / lowering block 212, a multi-joint arm 216 supported by the lifting / lowering block 212, a holding piece 218 attached to the end of the multi-joint arm 216 in such a manner that it can is to be turned upside down, and a drive source (not shown) that drives the multi-joint arm 216.

[0056] The description is made with reference to Fig. 9. The X-axis feed means 210 supported by the support wall 206 includes a ball screw 220 having a nut portion 220a fixed to the X-axis movable member 208 and extending in the X-axis direction, and a motor 222 that rotates the ball screw 220 and moves the X-axis movable member 208 in the X-axis direction along a guide rail 206a of the support wall 206. The raising / lowering means 214, which is supported by the X-axis movable member 208, includes a ball screw 224 connected to the raising / lowering block 212 and extending in the Z-axis direction, and a motor 226 that rotates the ball screw 224 and raises and lowers the raising / lowering block 212 along guide rails 208a of the X-axis movable member 208.The drive source, configured with an air drive source or an electric drive source, drives the multi-joint arm 216 to position the holding piece 218 at any position in each of the X-axis direction, the Y-axis direction, and the Z-axis direction, and to invert the holding piece 218. The holding piece 218, which has a plurality of unillustrated suction holes formed in a single surface, is connected to an unillustrated suction means.

[0057] Furthermore, in the receiving means 202, by orienting the suction holes of the holding piece 218 downward and generating a suction force for the holding piece 218 by the suction means, a wafer supported by the wafer supporting part 118 of the tray 9 can be sucked and held by the holding piece 218, and the wafer held by the holding piece 218 can be received in the cassette 198 received in the cassette storage device 200.

[0058] In the Fig. 17A to 17C, an ingot 230 is shown for which processing can be performed by the wafer manufacturing apparatus 2. The ingot 230 is formed in a circular columnar shape as a whole from a hexagonal SiC single crystal and has a first surface 232 having a circular shape, a second surface 234 having a circular shape on the opposite side of the first surface 232, a peripheral surface 236 arranged between the first surface 232 and the second surface 234, the c-axis ( <0001> -direction) which reaches the second surface 234 from the first surface 232, and the c-plane ({0001}-plane) perpendicular to the c-axis.

[0059] In the ingot 230, the c-axis is inclined with respect to a normal 238 to the first surface 232, and a deviation angle α (for example, α equal to 1°, 3°, or 6°) is formed by the c-plane and the first surface 232. The direction in which the deviation angle α is formed is shown in the Fig. 17A to 17C by an arrow A. In addition, a first orientation plane 240 and a second orientation plane 242 are formed in the peripheral surface 236 of the ingot 230, which represent the crystal orientation and have a rectangular shape. The first orientation plane 240 is parallel to the direction A in which the deviation angle α is formed, and the second orientation plane 240 is perpendicular to the direction A in which the deviation angle α is formed. As shown in Fig. 17B, ​​a length L2 of the second alignment plane 242, viewed from above, is shorter than a length L1 of the first alignment plane 240 (L2 <L1).

[0060] The ingot for which the processing can be performed by the wafer manufacturing apparatus 2 is not limited to the above-described ingot 230, and may be, for example, a hexagonal SiC single-crystal ingot in which the c-axis is not inclined with respect to the normal to the first surface and the deviation angle between the c-plane and the first surface is 0° (that is, the normal to the first surface corresponds to the c-axis), or may be an ingot formed of a material other than SiC single-crystal, such as gallium nitride (GaN).

[0061] When a wafer is manufactured from the ingot 230 by the wafer manufacturing apparatus 2 described above, an ingot receiving step is first performed, which causes the ingot 230 to be received in the ingot storage device 11. In the ingot receiving step of the present embodiment, first, four ingots 230 are prepared, and the ingot support members 117 of four trays 9 are made to hold the four ingots 230 as shown in Fig. 1. Subsequently, the respective trays 9, which support the ingots 230, are placed on the respective placement tables 146 of the ingot storage device 11 to be picked up.

[0062] After the ingot receiving step is performed, a conveying step of conveying the ingot 230 from the ingot storage device 11 to the laser irradiation unit 6 by the ingot supply unit 12 and the conveyor unit 10 is first performed. In the ingot 230, the end surfaces (first surface 232 and second surface 234) are normally planarized to such an extent that they do not obstruct the incidence of a laser beam in a separation layer formation step described later. Therefore, in the present embodiment, an example will be described in which the ingot 230 is conveyed from the ingot storage device 11 to the laser irradiation unit 6 during the first conveying step.However, if the end surfaces of the ingot 230 have not been planarized to such an extent that they do not obstruct the incidence of the laser beam in the separation layer forming step, the ingot 230 may be conveyed from the ingot storage device 11 to the ingot grinding unit 4 during the first conveying step.

[0063] In the first conveying step, first, the raising / lowering plate 186 of the elevator 168 of the ingot supply unit 12 is raised or lowered, and the raising / lowering plate 186 is positioned at the position where the upper surface of the placement table 146 at any position (for example, the uppermost stage) of the ingot storage device 11 and the upper surface of the receiving table 160 are at the same height. Subsequently, the air cylinder 174 of the coupling part 166 is actuated to insert one of the pair of tapered pins 178 of the coupling part 166 into the driving force transmission part 150 of the ingot storage device 11 and insert the other of the pair of tapered pins 178 into the driving force transmission part 172 of the ingot supply unit 12. Subsequently, the motor 164 of the ingot supply unit 12 is rotated to rotate the first endless belt 148 together with the second endless belts 162.Thereby, the tray 9 placed on the placement table 146 is fed out by the first endless belt 148 in the Y-axis direction and fed to the receiving table 160 of the ingot supply unit 12.

[0064] After the tray 9 is fed to the receiving table 160, the rotation of the motor 164 is stopped. Furthermore, the piston rod 174b of the air cylinder 174 is moved from the retracted position to the extended position. This releases the connection between one of the pair of tapered pins 178 and the driving force transmission part 150 of the ingot storage device 11, and releases the connection between the other of the pair of tapered pins 178 and the driving force transmission part 172 of the ingot supply unit 12. By moving the raising / lowering plate 186 of the elevator 168, the upper surface of the receiving table 160 on which the tray 9 is placed is adjusted to the same height as the upper surfaces of the endless belts 127 of the forward conveyor belt 121 of the conveyor belt unit 10.Subsequently, the second endless belts 162 are rotated by rotation of the motor 164, and the tray 9 placed on the upper surface of the receiving table 160 is fed to the forward conveyor belt 121.

[0065] After the tray 9 is fed to the forward conveyor belt 121, the tray 9 is conveyed by the forward conveyor belt 121 to the position opposite the laser irradiation unit 6. At the same time, the raising / lowering plate 131 of the tray stopper 129, which is arranged at the position opposite the ingot grinding unit 4, is positioned at the passing position, and the raising / lowering plate 131 of the tray stopper 129, which is arranged at the position opposite the laser irradiation unit 6, is positioned at the stopping position. Due to this, the tray 9 conveyed by the forward conveyor belt 121 in the Y1 direction can be made to pass over the tray stopper 129 arranged at the position opposite the ingot grinding unit 4 and can be stopped by the tray stopper 129 at the position opposite the laser irradiation unit 6.

[0066] Subsequently, the raising / lowering plate 131 of the tray stopper 129 is raised to the separation position to separate the lower surface of the stopped tray 9 from the upper surfaces of the endless belts 127. Subsequently, the multi-joint arm 144 of the second transfer means 142 is driven, and the suction pad 145 is brought into close contact with the upper surface of the ingot 230 (the first surface 232 in the present embodiment). Then, the suction means connected to the suction pad 145 is actuated to generate suction force for the suction pad 145, and the ingot 230 is sucked and held by the suction pad 145. Thereafter, the suction gripper 145 is moved by the multi-joint arm 144, and the lower surface (in the present embodiment, the second surface 234) of the ingot 230 sucked and held by the suction gripper 145 is, as shown in Fig. 18, brought into contact with the upper surface of the second holding table 60 of the laser irradiation unit 6. At this time, the second holding table 60 is at the ingot mounting / ingot removal position (in Fig. 4) for attaching / removing an ingot.

[0067] As with reference to Fig. 18, in the circumferential edge of the circular suction chuck 66 of the present embodiment, a first linear part 66a corresponding to the first alignment plane 240 of the ingot 230 and a second linear part 66b corresponding to the second alignment plane 242 are formed, and the ingot 230, in which the first alignment plane 240 and the second alignment plane 242 are formed, can be sucked and held by the suction chuck 66 with a predetermined suction force. Then, the suction means connected to the suction piece 145 is stopped to deactivate the suction force of the suction piece 145 and place the ingot 230 on the upper surface of the second holding table 60. In this way, the first conveying step is carried out by conveying the ingot 230 from the ingot storage device 11 to the laser irradiation unit 6.Although an illustrative diagram is omitted, in the suction chuck 22 of the first holding table 14 of the ingot grinding unit 4 and the suction chuck 86 of the third holding table 80 of the wafer separating unit 8, a first rectilinear part corresponding to the first alignment plane 240 and a second rectilinear part corresponding to the second alignment plane 242 are also formed.

[0068] After the first conveying step is performed, the separation layer forming step of holding the ingot 230 by the second holding table 60 and positioning the focal point of a laser beam having such a wavelength that is transmissible through the ingot 230 at a depth from the upper surface of the ingot 230 held by the second holding table 60 that corresponds to the thickness of the wafer to be manufactured, and irradiating the ingot 230 with the laser beam to form a separation layer is performed by the laser irradiation unit 6.

[0069] In the separation layer forming step, first, a suction force is generated for the upper surface of the second holding table 60, and the ingot 230 is sucked and held by the second holding table 60. Subsequently, the second holding table 60 is moved in the X-axis direction by the X-axis feeding means, and the Y-axis movable member is moved in the Y-axis direction by the Y-axis feeding means to position the ingot 230 under the aligning means 76. Subsequently, the ingot 230 is imaged by the aligning means 76 from the upper side of the ingot 230. Then, based on the image of the ingot 230 captured by the aligning means 76, the second holding table 60 is rotated and moved by the motor for the second holding table and the X-axis feeding means, and the Y-axis movable member is moved by the Y-axis feeding means.This sets the orientation of the ingot 230 to a predetermined orientation, and adjusts the positions of the ingot 230 and the light collector 74 in the XY plane. When the orientation of the ingot 230 is adjusted, as shown in FIG. Fig. 19A, the second alignment plane 242 is aligned with the X-axis direction. Therefore, the direction perpendicular to the direction A in which the deviation angle α is formed is aligned with the X-axis direction, and the direction A in which the deviation angle α is formed is aligned with the Y-axis direction.

[0070] Then, the light collector 74 is raised and lowered by the focal point position adjusting means, and the focal point FP is set as shown in Fig. 19B, positioned at a depth from the first surface 232 of the ingot 230 corresponding to the thickness of the wafer to be manufactured. While the second holding table 60 is moved by the X-axis feed means in the X-axis direction aligned with the direction perpendicular to the direction A in which the deviation angle α is formed, the ingot 230 is subsequently irradiated from the light collector 74 with the pulsed laser beam LB having a wavelength transmissible through the ingot 230. Due to this, SiC is separated into Si and carbon (C) by the irradiation with the pulsed laser beam LB, and the pulsed laser beam LB, which is next irradiated, is absorbed by the previously formed C, so that SiC is separated into Si and C in a chain reaction manner.In addition, cracks 248 are generated which extend isotropically along the c-plane from parts 246 where SiC is separated into Si and C.

[0071] Thereafter, by moving the Y-axis movable member by the Y-axis feeding means, pitch feeding of the focal point FP relative to the ingot 230 in the Y-axis direction aligned with the direction A in which the deviation angle α is formed is performed by a predetermined pitch amount Li in a range not exceeding the width of the cracks 248. By alternately repeating the irradiation of the pulsed laser beam LB and the pitch feeding, a plurality of partition parts 246 continuously extending in the direction perpendicular to the direction A in which the deviation angle α is formed are formed at intervals of the predetermined pitch amount Li in the direction A in which the deviation angle α is formed.Furthermore, the cracks 248 extending isotropically from the separation parts 246 along the c-plane are sequentially generated to cause the cracks 248 adjacent in the direction A in which the deviation angle α is formed to overlap in the up-down direction. At the depth from the top surface of the ingot 230 corresponding to the thickness of the wafer to be manufactured, a separation layer 250 constructed with the separation parts 246 and the cracks 248 can be formed, and the strength for separating a wafer from the ingot 230 is reduced. After the separation layer 250 is formed, the second holding table 60 is positioned at the ingot attachment / ingot removal position, and the suction force of the second holding table 60 is deactivated. The separation layer formation step can be performed under, for example, the following processing conditions. Wavelength of the pulsed laser beam: 1064 nm Repetition frequency: 80 kHz Average output power: 3.2 watts Pulse width: 4 ns Focal spot diameter: 3 µm Numerical aperture (NA) of the converging lens: 0.43 Position of the focal point in the Z-axis direction: 300 µm from the top surface of the ingot Feed speed of the second holding table: 120 to 260 mm / s Graduation amount: 250 to 400 µm

[0072] After the separation layer formation step is performed, a second conveying step of conveying the ingot 230, in which the separation layer 250 has been formed via the laser irradiation unit 6, to the wafer separation unit 8 is performed by the conveyor unit 10. In the second conveying step, first, the multi-joint arm 144 of the second transfer means 142 is driven, and the suction pad 145 is brought into close contact with the first surface 232 of the ingot 230 on the second holding table 60 to suck and hold the ingot 230 by the suction pad 145. Subsequently, the suction pad 145 is moved by the multi-joint arm 144, and the second surface 234 of the ingot 230 sucked and held by the suction pad 145 is brought into contact with the ingot support part 117 of the tray 9.Thereafter, the suction force of the suction pad 145 is deactivated to cause the ingot support part 117 of the tray 9 to support the ingot 230. Subsequently, the tray 9 is placed on the endless belts 127 of the forward conveyor belt 121 by lowering the raising / lowering plate 131 of the tray stopper 129 from the separation position to the passing position.

[0073] After the forward conveyor belt 121 is placed on the tray 9, the tray 9 is conveyed by the forward conveyor belt 121 to the position opposite to the wafer separation unit 8 (the end point of the forward conveyor belt 121 in the present embodiment). At this time, the raising / lowering plate 135 is positioned at a height where the upper surface of the Y-axis movable plate 137 of the conveying means 123 is lower than the upper surfaces of the endless belts 127 of the forward conveyor belt 121, and the stopper piece 138 comes into contact with the tray 9 conveyed by the forward conveyor belt 121. Furthermore, the Y-axis movable plate 137 is positioned at the advanced position.This can bring the stopper piece 138 into contact with the tray 9 conveyed by the forward conveyor belt 121 in the direction Y1 and stop the tray 9 at the position opposite to the wafer separation unit 8.

[0074] Subsequently, the raising / lowering plate 135 of the conveying means 123 is raised to mount the stopped tray 9 on the upper surface of the Y-axis movable plate 137 and separate the lower surface of the tray 9 from the upper surfaces of the endless belts 127. Then, the multi-joint arm 144 of the third transfer means 143 is driven, and the suction pad 145 is brought into close contact with the first surface 232 of the ingot 230, and the ingot 230 is sucked and held by the suction pad 145. Subsequently, the suction pad 145 is moved by the multi-joint arm 144, and the second surface 234 of the ingot 230, sucked and held by the suction pad 145, is brought into contact with the upper surface of the third holding table 80 of the wafer separation unit 8. At this time, the third holding table 80 is positioned at the ingot mounting / unmounting position (shown in Fig. 6). Then, the suction force of the suction pad 145 is deactivated, and the ingot 230 is placed on the upper surface of the third holding table 80. In this way, the second conveying step of conveying the ingot 230 from the laser irradiation unit 6 to the wafer separation unit 8 is performed.

[0075] After the second conveying step is performed, a wafer separating step of holding the ingot 230 in which the separation layer 250 has been formed by the third holding table 80 and holding the upper surface of the ingot 230 held by the third holding table 80 to separate a wafer from the separation layer 250 is performed by the wafer separating unit 8.

[0076] In the wafer separation step, the ingot 230 is first sucked and held by the third holding table 80. As shown in Fig. 21A, the third holding table 80 is subsequently positioned at a wafer separation position under the liquid bath 94. Then, the arm 92 is lowered by the arm moving means, and the lower end of the skirt wall 98 of the liquid bath 94 is, as shown in Fig. 21B, brought into close contact with the upper surface of the third holding table 80.

[0077] As in Fig. 7, the piston rod 108b of the air cylinder 108 is then moved, and the lower surface of the suction pad 112 is brought into close contact with the first surface 232 of the ingot 230. Then, suction force is generated for the lower surface of the suction pad 112, and the ingot 230 is sucked and held by the suction pad 112 from the first surface 232 side. Subsequently, the liquid supply means connected to the liquid supply part 100 is actuated to supply the liquid 106 (for example, water) from the liquid supply part 100 to the liquid receiving space 104 until the ultrasonic vibration generating element 110 is immersed. Subsequently, the ultrasonic vibration generating element 110 is actuated to apply ultrasonic vibration to the ingot 230. This stimulates the separation layer 250 and lengthens the cracks 248 to further reduce the strength of the separation layer 250.

[0078] Then, as in Fig. 22, by raising the arm 92 via the arm moving means in the state where the ingot 230 is sucked and held by the suction adhesion piece 112, a wafer 252 to be produced can be separated from the ingot 230 by using the separation layer 250 as a starting point. Moreover, when the arm 92 is raised, the liquid 106 is discharged from the liquid accommodating space 104, and the liquid 106 is discharged to the outside of the wafer separation unit 8 through an unillustrated discharge port formed in the base 84. After the wafer 252 is separated from the ingot 230, the third holding table 80 is positioned at the ingot attachment / ingot removal position, and the suction force of the third holding table 80 is deactivated.

[0079] When the ultrasonic vibration is applied to the ingot 230, a gap (for example, 2 to 3 mm) can be created between the upper surface of the ingot 230 and the lower surface of the suction pad 112. Furthermore, when the wafer 252 is separated from the ingot 230 by using the separation layer as a starting point, the wafer 252 can be separated from the ingot 230 by lifting the suction pad 145 after the upper surface of the ingot 230 is sucked and held by the suction pad 145 of the third transfer means 143.

[0080] After the wafer separation step is performed, a third conveying step of conveying the wafer 252 separated from the ingot 230 from the wafer separation unit 8 to the cassette 198 of the cassette storage device 200 and causing the wafer 252 to be picked up is performed by the conveyor unit 10, the ingot supply unit 12, and the pick-up means 202. In the third conveying step, first, the multi-joint arm 144 of the third transfer means 143 is driven, and the suction pad 145 of the third transfer means 143 is brought into close contact with a separation surface 252a of the wafer 252 to adhere to the suction pad 112 of the wafer separation means 82 by negative pressure, and the wafer 252 is sucked and held by the suction pad 145.Subsequently, the suction force of the suction pad 112 of the wafer separating means 82 is deactivated, and the wafer 252 is transferred from the suction pad 112 of the wafer separating means 82 to the suction pad 145 of the third transfer means 143. Then, the suction pad 145 is moved by the multi-joint arm 144, and the wafer 252 sucked and held by the suction pad 145 is brought into contact with the wafer support part 118 of the tray 9. Subsequently, the suction force of the suction pad 145 is deactivated to cause the wafer support part 118 of the tray 9 to support the wafer 252.

[0081] Furthermore, in order to convey the ingot 230 from which the wafer 252 has been separated by the wafer separating unit 8, along with the conveyance of the wafer 252 from the wafer separating unit 8 to the ingot grinding unit 4, the multi-joint arm 144 is driven in the third conveying step, and the suction pad 145 is brought into close contact with a separating surface 230a of the ingot 230 on the third holding table 80 to suck and hold the ingot 230 by the suction pad 145. Subsequently, the suction pad 145 is moved by the multi-joint arm 144, and the ingot 230 sucked and held by the suction pad 145 is conveyed to the ingot support part 117 of the tray 9 to cause the ingot support part 117 to support the ingot 230. Then, the Y-axis movable plate 137 of the conveyor 123 on which the tray 9 is located or attached is positioned at the retracted position.Then, the raising / lowering plate 135 is lowered, and the upper surface of the Y-axis movable plate 137 is positioned slightly upward relative to the upper surfaces of the endless belts 127 of the reverse conveyor belt 122. Then, the tray 9 is placed on the endless belts 127 of the reverse conveyor belt 122 by positioning the Y-axis movable plate 137 at the advanced position and lowering the raising / lowering plate 135.

[0082] After the tray 9 is placed on the reverse conveyor belt 122, the tray 9 is conveyed by the reverse conveyor belt 122 to the end point of the reverse conveyor belt 122. At this time, the upper surface of the receiving table 160 is adjusted by the elevator 168 of the ingot supply unit 12 to the same height as the upper surfaces of the endless belts 127 of the reverse conveyor belt 122. Furthermore, the second endless belts 162 are rotated by the motor 164 so that the upper surface sides of the second endless belts 162 move in the Y2 direction. Thus, the tray 9, conveyed by the reverse conveyor belt 122 in the Y2 direction, is placed on the upper surface of the receiving table 160.

[0083] After the tray 9 is placed on the receiving table 160, the rotation of the motor 164 is stopped. Furthermore, the raising / lowering plate 186 of the elevator 168 is moved, and the upper surface of the receiving table 160 on which the tray 9 is placed is adjusted to the same height as the upper surfaces of the endless belts 127 of the forward conveyor belt 121 of the conveyor belt unit 10. At this time, the piston rod 174b of the air cylinder 174 is positioned at the retracted position to prevent interference with the movement of the raising / lowering plate 186.Thereafter, by moving the elevating / lowering block 212 by the X-axis feeding means 210 and the elevating / lowering means 214 of the receiving means 202 and driving the multi-joint arm 216, the holding piece 218 is brought into close contact with the upper surface of the wafer 252 supported by the tray 9 on the receiving table 160, and the wafer 252 is sucked and held by the holding piece 218. By moving the holding piece 218 via the X-axis feed means 210, the elevating / lowering means 214, and the multi-joint arm 216, the wafer 252 sucked and held by the holding piece 218 is then carried out from the tray 9 and moved into the cassette 198 of the cassette storage device 200. Then, the suction force of the holding piece 218 is deactivated. In this way, the wafer 252 separated from the ingot 230 is conveyed and received by the wafer separation unit 8 to the cassette 198 of the cassette storage device 200.

[0084] After the wafer is carried out from the tray 9, the second endless belts 162 are rotated to guide the tray 9 placed on the upper surface of the receiving table 160 to the forward conveyor belt 121 and convey the tray 9 by the forward conveyor belt 121. At this time, the raising / lowering plate 131 of the tray stopper 129, which is located at the position opposite to the ingot grinding unit 4, is positioned at the stop position. This can stop the tray 9, which is conveyed by the forward conveyor belt 121 in the Y1 direction, by the tray stopper 129 at the position opposite to the ingot grinding unit 4.

[0085] Subsequently, the raising / lowering plate 131 of the tray stopper 129 is raised to the separation position to separate the lower surface of the stopped tray 9 from the upper surfaces of the endless belts 127. Subsequently, the multi-joint arm 144 of the first transfer means 141 is driven, and the suction pad 145 is brought into close contact with the separation surface 230a of the ingot 230 to suck and hold the ingot 230 by the suction pad 145. Then, the suction pad 145 is moved by the multi-joint arm 144, and the second surface 234 of the ingot 230 is brought into contact with the upper surface of the first holding table 14 of the ingot grinding unit 4, which is positioned at the ingot attachment / ingot removal position. Thereafter, the suction force of the suction piece 145 is deactivated, and the ingot 230 is placed on the upper surface of the first holding table 14.In this way, the ingot 230 from which the wafer 252 has been separated is conveyed from the wafer separation unit 8 to the ingot grinding unit 4.

[0086] After the third conveying step is performed, the ingot grinding unit 4 performs an ingot grinding step of holding the ingot 230 from which the wafer 252 has been separated by the first holding table 14 and grinding the separation surface 230a of the ingot 230 held by the first holding table 14 to planarize the separation surface 230a.

[0087] Referring to Fig.3, in the ingot grinding step, first, suction force is generated for the upper surface of the first holding table 14, and the ingot 230 is sucked and held by the first holding table 14. Subsequently, the first holding table 14 holding the ingot 230 is positioned at the grinding position. After that, the first holding table 14 holding the ingot 230 is rotated counterclockwise from the top at a predetermined rotation speed (for example, 300 revolutions per minute). Furthermore, the spindle 36 is rotated counterclockwise from the top at a predetermined rotation speed (for example, 6000 revolutions per minute). Subsequently, the spindle housing 30 is lowered, and the abrasives 44 are brought into contact with the parting surface 230a of the ingot 230. Then, the housing 30 is lowered at a predetermined grinding feed rate (for example, 1.0 µm per second).This can grind the separation surface 230a of the ingot 230 from which the wafer 252 has been separated, and planarize the separation surface 230a of the ingot 230 to such an extent that the incidence of the pulsed laser beam LB is not obstructed in the separation layer formation step. After the separation surface 230a of the ingot 230 is planarized, the first holding table 14 holding the ingot 230 is positioned at the ingot attachment / detachment position, and the suction force of the first holding table 14 is deactivated.

[0088] After the ingot grinding step is performed, a fourth conveying step is performed, which involves conveying the ingot 230, in which the parting surface 230a has been planarized by the ingot grinding unit 4, to the laser irradiation unit 6 by the conveyor belt unit 10. In the fourth conveying step, first, the multi-joint arm 144 of the first transfer means 141 is driven, and the suction pad 145 is brought into close contact with the parting surface 230a of the ingot 230 on the first holding table 14 to suck and hold the ingot 230 by the suction pad 145. Subsequently, the suction pad 145 is moved by the multi-joint arm 144, and the second surface 234 of the ingot 230, sucked and held by the suction pad 145, is brought into contact with the ingot support part 117 of the tray 9.Thereafter, the suction force of the suction pad 145 is deactivated to cause the ingot support part 117 of the tray 9 to support the ingot 230. Then, the tray 9 is placed on the endless belts 127 of the forward conveyor belt 121 by lowering the raising / lowering plate 131 of the tray stopper 129 from the separation position to the passing position.

[0089] After the tray 9 is placed on the forward conveyor belt 121, the tray 9 is conveyed by the forward conveyor belt 121 to the position opposite the laser irradiation unit 6. At this time, the raising / lowering plate 131 of the tray stopper 129, which is positioned at the position opposite the laser irradiation unit 6, is positioned at the stop position, and the tray 9, conveyed by the forward conveyor belt 121 in the Y1 direction, is stopped by the tray stopper 129 at the position opposite the laser irradiation unit 6. Subsequently, the raising / lowering plate 131 of the tray stopper 129 is raised to the separation position to separate the lower surface of the stopped tray 9 from the upper surfaces of the endless belts 127.Thereafter, the multi-joint arm 144 of the second transfer means 142 is driven, and the suction pad 145 is brought into close contact with the parting surface 230a of the ingot 230 to suck and hold the ingot 230 by the suction pad 145. Subsequently, the multi-joint arm 144 of the second transfer means 142 is driven, and the suction pad 145 is brought into close contact with the parting surface 230a of the ingot 230 to suck and hold the ingot 230 by the suction pad 145. Thereafter, the suction pad 145 is moved by the multi-joint arm 144, and the second surface 234 of the ingot 230 sucked and held by the suction pad 145 is brought into contact with the upper surface of the second holding table 60 of the laser irradiation unit 6, which is positioned at the ingot attachment / detachment position. Then, the suction force of the suction pad 145 is deactivated, and the ingot 230 is placed on the upper surface of the second holding table 60.In this way, the fourth conveying step of conveying the ingot 230 in which the parting surface 230a has been planarized from the ingot grinding unit 4 to the laser irradiation unit 6 is carried out.

[0090] After the fourth conveying step is performed, the above-described separation layer forming step is performed by the laser irradiation unit 6. Furthermore, by repeatedly performing the separation layer forming step, the wafer separating step, the ingot grinding step, and the second to fourth conveying steps, the wafers 252 are produced in a producible quantity from the ingot 230, and the wafers 252 are accommodated in the cassette 198 of the cassette storage device 200.

[0091] Above, the respective steps performed for the ingot 230 in the wafer manufacturing apparatus 2 were described, with attention being paid to one ingot 230. However, in the wafer manufacturing apparatus 2, after performing the first conveying step of conveying the ingot 230 from the ingot stocker 11 to the laser irradiation unit 6, the wafers 252 can be manufactured by repeatedly performing the first conveying step at required intervals and repeatedly performing the separation layer forming step, the wafer dicing step, the ingot grinding step, and the second to fourth conveying steps with a plurality of ingots 230 at a time (four in the present embodiment) in a producible quantity from the plurality of ingots 230.Furthermore, if the quantity of wafers 252 produced from one ingot 230 is, for example, 100, the wafers 252 are accommodated in four cassettes 198, in which 25 wafers 252 can be accommodated. In this case, by providing an identification (ID) for the tray 9 to identify the tray 9 and providing a reading means that reads the ID of the tray 9 at the wafer manufacturing apparatus 2, the manufactured wafers 252 can be accommodated in the cassette 198 with a classification for each ingot 230.

[0092] As described above, the wafer manufacturing apparatus 2 of the present embodiment is constructed with at least the following components: the ingot grinding unit 4 constructed with at least the first holding table 14 that holds the ingot 230 and the grinding means 16 that grinds the upper surface of the ingot 230 held by the first holding table 14 to planarize the upper surface; the laser irradiation unit 6, which is constructed at least with the second holding table 60 that holds the ingot 230, and the laser irradiation means 62 that positions the focal point FP of the laser beam LB having such a wavelength that is transmissible through the ingot 230 at a depth from the upper surface of the ingot 230 held by the second holding table 60 that corresponds to the thickness of the wafer 252 to be manufactured, and irradiates the ingot 230 with the laser beam LB to form the separation layer 250;the wafer separation unit 8, which is constructed with at least the third holding table 80 that holds the ingot 230 and the wafer separation means 82 that holds the upper surface of the ingot 230 held by the third holding table 80 and separates the wafer 252 from the separation layer 250; the tray 9, which has the ingot support part 117 that supports the ingot 230 and the wafer support part 118 that supports the separated wafer 252; the conveyor belt unit 10 that conveys the ingot 230 supported by the tray 9 between the ingot grinding unit 4, the laser irradiation unit 6, and the wafer separation unit 8; the ingot storage device 11 in which the ingot 230 supported by the tray 9 is received;and the ingot supply unit 12, which supplies the ingot 230, supported by the tray 9 accommodated in the ingot storage device 11, to the conveyor unit 10. Therefore, a series of operations for manufacturing the wafer 252 from the ingot 230 can be performed automatically, and the manufacturing efficiency can be improved.

[0093] Furthermore, in the wafer manufacturing apparatus 2 of the present embodiment, each unit is configured independently. Therefore, the number of each unit can be changed according to the ingot conditions, such as material and size, customer requirements, etc. For example, if the wafer manufacturing apparatus 2 has multiple units of each type of unit, the same step can be performed simultaneously, and the amount of wafers manufactured per unit time can be increased. Furthermore, in the wafer manufacturing apparatus 2, by arranging a large number of units that require a comparatively long time to perform one step compared to a number of units that can perform one step in a comparatively short time, it is also possible to avoid a delay in the step and improve manufacturing efficiency.

[0094] In the separation layer forming step of the present invention, the example has been described in which the ingot 230 is moved relative to the focal point FP in the direction perpendicular to the direction A in which the deviation angle α is formed upon irradiation with the laser beam LB, and the focal point FP is moved relative to the ingot 230 in the direction A in which the deviation angle α is formed upon scheduling feed. However, the direction of relative movement of the focal point FP and the ingot 230 upon irradiation with the laser beam LB does not need to be the direction perpendicular to the direction A in which the deviation angle α is formed. Furthermore, the direction of relative movement of the focal point FP and the ingot 230 upon scheduling feed does not need to be the direction A in which the deviation angle α is formed.

[0095] If desired, a wafer grinding unit may further be provided that grinds the separation surface 252a of the wafer 252 separated from the ingot 230 to planarize the separation surface 252a, and the wafer 252 may be accommodated in the cassette 198 after the separation surface 252a of the wafer 252 has been planarized by the wafer grinding unit. Furthermore, a cleaning unit may be provided that cleans the ingot 230 ground by the ingot grinding unit and the wafer 252 ground by the wafer grinding unit.

[0096] The present invention is not limited to the details of the preferred embodiment described above. The scope of the invention is defined by the appended claims, and all changes and modifications that fall within the equivalent scope of the claims are therefore intended to be embraced by the invention.

Claims

[1] A wafer manufacturing apparatus (2) that manufactures a wafer (252) from an ingot (230), the wafer manufacturing apparatus (2) comprising: an ingot grinding unit (4) comprising a first holding table (14) holding the ingot (230) and a grinding means (16) grinding an upper surface of the ingot (230) held by the first holding table (14) to planarize the upper surface; a laser irradiation unit (6) comprising a second holding table (60) holding the ingot (230) and laser irradiation means (62) that positions a focal point of a laser beam (LB) having a wavelength transmissible through the ingot (230) at a depth from the upper surface of the ingot (230) held by the second holding table (60) that corresponds to a thickness of a wafer (252) to be produced, and irradiates the ingot (230) with the laser beam (LB) to form a separation layer; a wafer separation unit (8) comprising a third holding table (80) holding the ingot (230) and a wafer separation means (82) that holds the upper surface of the ingot (230) held by the third holding table (80) and separates a wafer (252) from the separation layer; a tray (9) having an ingot support part (117) supporting the ingot (230) and a wafer support part (118) supporting the separated wafer (252); a conveyor belt unit (10) that transports the ingot (230) supported by the tray (9) between the ingot grinding unit (4), the laser irradiation unit (6) and the wafer separation unit (8); an ingot storage device (11) in which the ingot (230) supported by the support (9) is received; and an ingot supply unit (12) which supplies the ingot (230) to the conveyor unit (10) which is supported by the tray (9) which is received in the ingot storage device (11), the ingot supply unit (12) being arranged between the conveyor unit (10) and the ingot storage device (11). [2] Wafer manufacturing apparatus (2) according to claim 1, wherein the ingot storage device (11) has a placing table (146) on which the tray (9) supporting the ingot (230) is placed, a first endless belt (148) arranged in the placing table (146) and leading out the tray (9) supporting the ingot (230), a driving force transmission part (150) connected to the first endless belt (148) and transmitting a driving force, and a frame (152) in which a plurality of the placing tables (146) are arranged in the vertical direction, and wherein the ingot supply unit (12) has a receiving table (160) that receives the tray (9) supporting the ingot (230) from the placing table (146), a second endless belt (162) that is arranged in the receiving table (160) and feeds the tray (9) supporting the ingot (230) to the conveyor belt unit (10), a motor (164) that drives the second endless belt (162), a coupling part (166) that is connected to the second endless belt (162) and transmits a driving force to the driving force transmitting part (150), and an elevator (168) that positions the receiving table (160) at any one of the plurality of placing tables (146) arranged in the vertical direction. [3] A wafer manufacturing apparatus according to claim 1 or 2, further comprising: a cassette storage device (200) in which a plurality of cassettes (198) receiving the separated wafers (252) are received; and a receiving means (202) which causes the wafer (252) supported by the wafer support part (118) of the tray (9) to be received in the cassette (198) received in the cassette storage device (2).

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