WAFER TRAINING APPARATUS

Abstract

A wafer forming apparatus (2) for forming a wafer (30) from a semiconductor ingot (24), the wafer forming apparatus (2) comprising: a conveyor tray (4) with an ingot receiving section (22) which receives the semiconductor ingot (24) and a wafer receiving section (28) which receives the wafer (30) formed from the semiconductor ingot, a belt conveyor unit (6) which conveys the conveyor tray (4) to each processing device, a cassette tray (10) on which cassettes (8) holding the wafers are arranged corresponding to the conveyor trays (4), and a transfer unit (12) which transfers the wafer from the wafer receiving section (28) of the conveyor tray to the cassette (8) arranged on the cassette tray (10), wherein the conveyor tray (4) is provided with an identification marking (34) and the cassette tray (10) or the cassette (8) corresponding to the conveyor tray (4) is provided with the same identification marking (34', 34") as the identification marking (34) provided on the conveyor tray.

Description

BACKGROUND OF THE INVENTIONTechnical field

[0001] The present invention relates to a wafer forming apparatus for forming a wafer from a semiconductor ingot. Description of the state of the art

[0002] Devices such as integrated circuits (ICs), large-scale integration circuits (LSIs), and light-emitting diodes (LEDs) are formed in a functional layer stacked on a front surface of a wafer made of silicon (Si) or sapphire (Al2O3) or the like, and separated by streets. Furthermore, power devices, LEDs, or the like are formed in a functional layer stacked on a front surface of a wafer made of single-crystal silicon carbide (single-crystal SiC), and separated by streets. The wafer formed with the devices is processed along the streets by a dicing device or a laser processing device to divide them into individual device chips. The divided device chips are used for electronic devices such as mobile phones and personal computers.

[0003] The wafer to be formed with devices is generally formed by cutting a cylindrical semiconductor ingot into a thin shape with a wire saw. The front surface and one back surface of the thus-cut wafer are polished to a mirror surface (see, for example, JP 2000-094221 A). However, if the semiconductor ingot is cut with a wire saw and the front and back surfaces of the thus-cut wafer are polished, most of the semiconductor ingot (70% to 80%) is discarded, which is uneconomical. In particular, the single-crystal SiC ingot has high hardness, is difficult to cut with a wire saw, and cutting is time-consuming, so productivity is poor. Furthermore, the semiconductor ingot has a high unit price, and efficient wafer formation is problematic.

[0004] In view of this, a wafer forming apparatus has been proposed in which a laser beam having a wavelength such that it passes through the single-crystal SiC is applied to the single-crystal SiC ingot, a focal point of the laser beam is positioned inside the single-crystal SiC ingot to form a release layer at a planned cutting plane, and the wafer is released from the single-crystal SiC ingot along the planned cutting plane formed with the release layer (see, for example, JP 2019 - 106 458 A).

[0005] Furthermore, in the wafer forming apparatus disclosed in JP 2019-106458 A, a series of operations can be efficiently performed, including continuously placing a plurality of conveying trays (for example, four conveying trays) on a belt conveying unit, conveying the semiconductor ingot to each processing apparatus by the belt conveying unit to form a wafer from the semiconductor ingot, accommodating the wafer in the same conveying tray as that for the semiconductor ingot from which the wafer is formed, and accommodating the wafer in a cassette associated with the semiconductor ingot in a wafer-out conveying section.

[0006] JP H04 - 159 902 A discloses further prior art. PRESENTATION OF THE INVENTION

[0007] However, when the operation of the wafer forming apparatus is stopped due to a shutdown or a malfunction, the conveying tray is conveyed out of the belt conveying unit, and then the operation is resumed, it may be impossible to accommodate the wafer in the cassette associated with the semiconductor ingot, and the parent-child relationship between the semiconductor ingot and the wafer may become unclear.

[0008] Accordingly, it is an object of the present invention to provide a wafer forming apparatus that ensures that even in the event of a shutdown or a malfunction, the parent-child relationship between a semiconductor ingot and a wafer is not broken but is always clear.

[0009] According to one aspect of the present invention, a wafer forming apparatus for forming a wafer from a semiconductor ingot is provided, the wafer forming apparatus comprising: a conveyor tray having an ingot receiving portion that receives the semiconductor ingot and a wafer receiving portion that receives the wafer formed from the semiconductor ingot, a belt conveyor unit that conveys the conveyor tray to each processing device, a cassette tray on which cassettes that receive the wafers are arranged corresponding to the conveyor trays, and a transfer unit that transfers the wafer from the wafer receiving portion of the conveyor tray to the cassette placed on the cassette tray,wherein the conveyor tray is provided with an identification mark and the cassette tray or the cassette corresponding to the conveyor tray is provided with the same identification mark as the identification mark provided on the conveyor tray.,

[0010] Preferably, the identification mark is a color or a symbol or a character or a number or a pattern or an image or a combination thereof.

[0011] According to the present invention, even in the event of a shutdown or a failure that stops the operation of a wafer processing apparatus, a wafer can be securely housed in a cassette associated with a semiconductor ingot, and the parent-child relationship between the semiconductor ingot and the wafer is not broken but is always unique.

[0012] The above and other objects, features and advantages of the present invention and the mode for carrying them out will become more apparent and the invention itself will be best understood by studying the following description and the appended claims with reference to the attached drawings which show a preferred embodiment of the invention. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1 is a perspective view of a wafer forming apparatus according to an embodiment of the present invention; Fig. 2 is a perspective view of a conveyor tray shown in Fig. 1; and Fig. 3 is a partial perspective view of the Fig. 1 shown wafer forming apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] A wafer forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Fig. The wafer forming apparatus 2 shown in Fig. 1 includes a conveyor tray 4 that accommodates a semiconductor ingot (hereinafter referred to simply as an ingot) and a wafer, a belt conveyor unit 6 that conveys the conveyor tray 4 to each processing apparatus, a cassette tray 10 on which cassettes 8 that accommodate the wafers are arranged corresponding to the conveyor trays 4, and a transfer unit 12 that transfers the wafer from the conveyor tray 4 to the cassette 8 arranged on the cassette tray 10.

[0014] Referring to Fig. 2, the conveyor tray 4 comprises a rectangular upper wall 14, a rectangular lower wall 16 disposed at the bottom of the upper wall 14, a pair of rectangular side walls 18 connecting the upper wall 14 and the lower wall 16, and a tunnel 20 defined by the upper wall 14 and the lower wall 16 and the pair of side walls 18.

[0015] An upper surface of the top wall 14 is formed with an ingot receiving portion 22 for receiving an ingot. The ingot receiving portion 22 in the present embodiment includes an annular first ingot receiving portion 22a recessed downward from the upper surface of the top wall 14, and a circular second ingot receiving portion 22b smaller in diameter than the first ingot receiving portion 22a and recessed further downward than the first ingot receiving portion 22a. The first ingot receiving portion 22a and the second ingot receiving portion 22b are concentrically formed.

[0016] The diameter of the first ingot receiving portion 22a is slightly (on the order of a few mm) larger than a cylindrical ingot 24 with a comparatively large diameter (for example, 6 inches), and the first ingot receiving portion 22a receives the ingot 24 with a comparatively large diameter. The diameter of the second ingot receiving portion 22b is slightly larger than a cylindrical ingot 26 with a comparatively small diameter (for example, 4 inches), and the second ingot receiving portion 22b receives the ingot 26 with a comparatively small diameter.

[0017] Thus, the ingot receiving portion 22 of the present embodiment includes the concentric first and second ingot receiving portions 22a and 22b corresponding to the ingots 24 and 26 of two sizes. Note that the ingot receiving portion 22 may be a single circular receiving recess corresponding to an ingot of a single size or may include a plurality of concentric receiving recesses corresponding to ingots of three or more sizes.

[0018] As in Fig. As shown in Figure 2, an upper surface of the bottom wall 16 is formed with a wafer receiving portion 28 for receiving the wafer formed from an ingot. The wafer receiving portion 28 of the present embodiment includes an annular first wafer receiving portion 28a recessed downward from the upper surface of the bottom wall 16 and a circular second wafer receiving portion 28b smaller in diameter than the first wafer receiving portion 28a and recessed further downward than the first wafer receiving portion 28a. The first wafer receiving portion 28a and the second wafer receiving portion 28b are concentrically formed.

[0019] The diameter of the first wafer receiving section 28a is slightly larger than a relatively large-diameter disk-shaped wafer 30 (e.g., 6 inches in diameter), and the first wafer receiving section 28a receives the relatively large-diameter wafer 30. The diameter of the second wafer receiving section 28b is slightly larger than a relatively small-diameter disk-shaped wafer 32 (e.g., 4 inches in diameter), and the second wafer receiving section 28b receives the relatively small-diameter wafer 32.

[0020] Thus, the wafer receiving portion 28 of the present embodiment includes the concentric first and second wafer receiving portions 28a and 28b corresponding to the wafers 30 and 32 of two sizes. Note that the wafer receiving portion 28 may be a single circular receiving recess corresponding to the wafer of a single size or may include a plurality of concentric receiving recesses corresponding to wafers of three or more sizes. Note that, unlike the present embodiment, the upper surface of the upper wall 14 may be formed with the wafer receiving portion 28, and the upper surface of the lower wall 16 may be formed with the ingot receiving portion 22.

[0021] As in Fig. 1 and Fig. As shown in Fig. 2, the conveyor tray 4 is provided with an identification mark 34. The identification mark 34 may be a color, a symbol, a character, a number, a pattern, or an image, or may be a combination of two or more of a color, a symbol, a character, a number, a pattern, and an image. In the present embodiment, characters A, B, C, and D are provided on an outer surface of the side wall of the conveyor tray 4 as the identification mark 34, but a color such as red, blue, green, and yellow may be provided as the identification mark 34, a number such as WW, XX, YY, and ZZ may be provided, or an image may be drawn.

[0022] As in Fig. 1, the conveyor tray 4, which receives an ingot (in the present embodiment, the ingot 24 with a comparatively large diameter), is accommodated in a conveyor tray frame 36. The conveyor tray frame 36, in the present embodiment, has four receiving sections 38 projecting in an X-axis direction shown in Fig. 1 is indicated by the arrow X. In the conveyor tray frame 36, the conveyor tray 4 can be moved from the viewer side in the X-axis direction in Fig. 1 can be accommodated in the receiving section 38, and the conveyor tray 4 in the receiving section 38 can be moved from the depth side in the X-axis direction in Fig. 1. It should be noted that a Y-axis direction that is Fig. 1 is indicated by the arrow Y, a direction orthogonal to the X-axis direction, a Z-axis direction which is in Fig. 1 indicated by the arrow Z, a vertical direction is orthogonal to the X-axis direction and the Y-axis direction, and an XY plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

[0023] With reference to the Fig. 1 and Fig. 3 describes each processing device to which the conveyor tray 4 that receives the ingot is transported. The wafer forming apparatus 2 in the present embodiment includes an ingot grinding unit 40, a laser deposition unit 42, and a wafer detachment unit 44 as processing devices.

[0024] As in Fig. As shown in Figure 3, the ingot grinding unit 40 includes a holding table 46 that holds the ingot under suction and can be rotated, and an abrasive 48 that grinds the upper surface of the ingot held by the holding table 46 under suction to planarize the upper surface. The abrasive 48 has a grinding wheel 50 equipped with grinding stones (not shown) and is rotatable. The ingot grinding unit 40 brings the grinding stones into contact with the upper surface of the ingot while rotating the holding table 46 with the ingot held thereon under suction and rotating the grinding wheel 50, thereby grinding and planarizing the upper surface of the ingot.

[0025] The laser application unit 42 includes a holding table 52 that holds the ingot under suction and is movable and rotatable in the X-axis direction, and a laser application means 54 that applies a laser beam to the ingot held by the holding table 52 under suction. The laser application means 54 includes a light concentrator 56 that focuses a pulsed laser beam emitted from a laser oscillator (not shown) to apply the pulsed laser beam to the ingot, and is movable in the Y-axis direction.

[0026] The laser application unit 42 applies a laser beam having such a wavelength to the ingot as to pass through the ingot, with a focal point of the laser beam positioned at a depth corresponding to the thickness of the wafer to be formed from the upper surface of the ingot, while the holding table 52 holding the ingot under suction is moved in the X-axis direction, or while the light concentrator 56 is moved in the Y-axis direction, thereby forming a release layer with lowered strength inside the ingot.

[0027] The wafer detaching unit 44 includes a holding table 58 that holds the ingot under suction and can be moved in the X-axis direction, a liquid tank body 60 that cooperates with the holding table 58 to form a liquid containing space, and an ultrasonic vibration generating element 62 that applies ultrasonic vibration to the ingot held by the holding table 58 under suction and holds the wafer detached from the ingot under suction.

[0028] The wafer detaching unit 44, after a liquid is received in the liquid receiving space formed by the holding table 58 that holds the ingot under suction and the liquid tank body 60, actuates the ultrasonic vibration generating element 62 to apply ultrasonic vibration to the ingot, thereby detaching the wafer from the ingot with the detaching layer as a starting point.

[0029] In the present embodiment, the conveyor tray 4 is conveyed from the belt conveyor unit 6 to the ingot grinding unit 40, the laser deposition unit 42 and the wafer detachment unit 44.

[0030] The belt conveyor unit 6 includes a forward belt conveyor 64 that conveys the conveying tray 4 in a Y1 direction, a reverse belt conveyor 66 that conveys the conveying tray 4 in a Y2 direction (direction opposite to Y1), a first conveyor unit 68 that conveys the conveying tray 4 from an end point of the forward belt conveyor 64 to a start point of the reverse belt conveyor 66 and stops the conveying tray 4 conveyed by the forward belt conveyor 64 at a position opposite to the wafer detaching unit 44, and a second conveyor unit 70 that conveys the conveying tray 4 from an end point of the reverse belt conveyor 66 to a start point of the forward belt conveyor 64.

[0031] Further, the belt conveyor unit 6 includes a first conveyor tray stopper 72 that can be lifted up and down and stops the conveyor tray 4 conveyed by the forward belt conveyor 64 at a position opposite to the ingot grinding unit 40, and a second conveyor tray stopper 74 that can be lifted up and down and stops the conveyor tray 4 conveyed by the forward belt conveyor 64 at a position opposite to the laser application unit 42.

[0032] Further, the belt conveyor unit 6 includes a first moving mechanism 76 that moves the ingot between the conveyor tray 4, which is stopped by the first conveyor tray stopper 72, and the ingot grinding unit 40, a second moving mechanism 78 that moves the ingot between the conveyor tray 4, which is stopped by the second conveyor tray stopper 74, and the laser deposition unit 42, and a third moving mechanism 80 that moves the ingot between the conveyor tray 4, which is stopped by the first conveyor unit 68, and the wafer detaching unit 44, and moves the wafer detached from the ingot from the wafer detaching unit 44 to the conveyor tray 4.

[0033] The first, second, and third moving mechanisms 76, 78, and 80, which may have a common configuration, each include an articulated arm 82 movable in the X-axis, Y-axis, and Z-axis directions, and a suction piece 84 mounted on a tip of the articulated arm 82 so as to be reversible. A surface of the suction piece 84 is formed with a plurality of suction holes (not shown) connected to suction means (not shown).

[0034] As in Fig. 1, the cassette tray 10 in the present embodiment has sixteen receiving sections 86 extending in the Y-axis direction. The cassettes 8, which receive the wafers detached from the ingot, are received in each receiving section 86. In the cassette tray 10, the cassettes 8 can be inserted into the receiving sections 86 from the viewer side in the Y-axis direction. Fig. 1, and the wafers can be stored in the cassettes 8 in the storage sections 86 from the depth side in the Y-axis direction in Fig. 1 can be recorded.

[0035] It is important that the cassette tray 10 corresponding to the conveying tray 4 be provided with the same identification mark 34' as the identification mark 34 provided on the conveying tray 4, or that the cassette 8 corresponding to the conveying tray 4 be provided with the same identification mark 34" as the identification mark 34 provided on the conveying tray 4. In the present embodiment, the same characters A, B, C, and D as the identification marks 34 of the conveying trays 4 are provided on the receiving portions 86 of the cassette tray 10 as identification marks 34', and the same characters A, B, C, and D as the identification marks 34 of the conveying trays 4 are provided on the outer surfaces of the cassettes 8 as identification marks 34".At the receiving sections 86 of the cassette tray 10, the cassette 8 is provided with the same identification mark 34" as the identification mark 34' of each receiving section 86. It should be noted that in . Fig. 1 the identification markings 34' are only applied to the receiving sections 86 on the uppermost step of the cassette tray 10, but the identification markings 34' can also be applied to the other receiving sections 86.

[0036] Referring to Fig. 3, the transfer unit 12 includes an articulated arm 88 movable in the X-axis, Y-axis, and Z-axis directions, and a suction piece 90 mounted on a tip of the articulated arm 88 so as to be reversible. A surface of the suction piece 90 is formed with a plurality of suction holes (not shown) connected to suction means (not shown). The transfer unit 12 conveys the conveying tray 4 in the conveying tray frame 36 to the belt conveying unit 6 and transfers the wafer from the wafer receiving section 28 of the conveying tray 4 to the cassette 8 arranged on the cassette tray 10.

[0037] At the time of forming a wafer from an ingot by the wafer forming apparatus 2 as shown in Fig. As shown in Figure 1, first, one or more ingots (in the present embodiment, four large-diameter ingots 24) are prepared. Next, the respective ingots 24 are received in the first ingot receiving sections 22a of the conveying trays 4, and the conveying trays 4 receiving the ingots 24 are housed in the conveying tray rack 36.

[0038] Subsequently, a first conveying step is performed in which the ingot 24 is conveyed from the conveying tray rack 36 to the laser deposition unit 42. Normally, the end surface of the ingot is planarized to such an extent that it does not obstruct the incidence of a laser beam in the release layer forming step described later, and therefore, in the present embodiment, an example is described in which the ingot 24 is conveyed from the conveying tray rack 36 to the laser deposition unit 42 in the first conveying step. However, in the case where the end surface of the ingot 24 is not planarized to such an extent that it does not obstruct the incidence of the laser beam in the release layer forming step, the ingot 24 may be conveyed from the conveying tray rack 36 to the ingot grinding unit 40 in the first conveying step.

[0039] In the first conveying step, the articulated arm 88 of the transfer unit 12 is first driven, and the suction piece 90 with the upwardly directed suction holes is inserted into the tunnel 20 of the conveyor tray 4. Subsequently, the suction piece 90 is slightly lifted in the tunnel 20, and the underside of the upper wall 14 of the conveyor tray 4 is held by suction by the suction piece 90. Subsequently, the conveyor tray 4, held by suction by the suction piece 90, is conveyed from the conveyor tray frame 36 to the forward belt conveyor 64.

[0040] After placing the conveying tray 4 on the forward belt conveyor 64, the conveying tray 4 is conveyed by the forward belt conveyor 64 in the Y1 direction to a position opposite the laser deposition unit 42. In this case, the first conveying tray stopper 72 is lowered and the second conveying tray stopper 74 is raised, thereby stopping the conveying tray 4 in a position opposite the laser deposition unit 42. Subsequently, the articulated arm 82 of the second moving mechanism 78 is driven, and the ingot 24 on the conveying tray 4 is held by the suction piece 84 under suction. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the conveying tray 4 to the holding table 52 of the laser deposition unit 42.

[0041] After the first conveying step is performed, a release layer forming step is performed at the laser deposition unit 42 in which the ingot 24 is held by the holding table 52 under suction, and a laser beam having a wavelength such that it passes through the ingot 24 is applied to the ingot 24, the focal point of the laser beam being positioned at a depth corresponding to the thickness of the wafer to be formed from the upper surface of the ingot 24 held by the holding table 52 under suction, to form a release layer.

[0042] After the release layer forming step is performed, a second conveying step is performed for conveying the ingot 24 formed with the release layer from the laser deposition unit 42 to the wafer detachment unit 44.

[0043] In the second conveying step, first, the articulated arm 82 of the second moving mechanism 78 is driven, the ingot 24 is held on the holding table 52 by the suction piece 84 under suction, and the suction force of the holding table 52 is released. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the holding table 52 to the first ingot receiving section 22a of the conveying tray 4.

[0044] Subsequently, the conveying tray 4 is conveyed by the forward belt conveyor 64 in the Y1 direction to a position opposite the wafer detachment unit 44. In this case, the conveying tray 4 is stopped at a position opposite the wafer detachment unit 44 by the first conveying unit 68. Subsequently, the articulated arm 82 of the third moving mechanism 80 is driven, and the ingot 24 on the conveying tray 4 is held by the suction piece 84 under suction. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the conveying tray 4 to the holding table 58 of the wafer detachment unit 44.

[0045] After the second conveying step is performed, a wafer detaching step is performed at the wafer detaching unit 44, in which the ingot 24 formed with the detachment layer is held by the holding table 58 under suction, the upper surface of the ingot 24 is held by the holding table 58 under suction, and the wafer 30 is detaching from the ingot 24 with the detachment layer as a starting point.

[0046] After the wafer removal step has been carried out, in a third conveying step the wafer 30 removed from the ingot 24 (see Fig. 2) is conveyed from the wafer detachment unit 44 to the cassette 8 on the cassette tray 10 and the ingot 24 with the wafer 30 detached therefrom is conveyed from the wafer detachment unit 44 to the ingot grinding unit 40.

[0047] In the third conveying step, first, the articulated arm 82 of the third moving mechanism 80 is driven, and the wafer 30 detached from the ingot 24 is held by the suction piece 84 under suction. Subsequently, the wafer 30 held by the suction piece 84 under suction is moved by the wafer detachment unit 44 to the first wafer receiving section 28a of the conveying tray 4.

[0048] Subsequently, the articulated arm 82 of the third moving mechanism 80 is driven, the ingot 24 is held on the holding table 58 by the suction piece 84 under suction, and the suction force of the holding table 58 is released. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the holding table 58 to the first ingot receiving section 22a of the conveying tray 4.

[0049] Subsequently, the conveyor tray 4, which holds the ingot 24 and the wafer 30, is conveyed by the first conveyor unit 68 from the forward belt conveyor 64 to the reverse belt conveyor 66. Subsequently, the conveyor tray 4 is conveyed in the Y2 direction by the reverse belt conveyor 66, and the conveyor tray 4 is transferred to the second conveyor unit 70. Subsequently, the conveyor tray 4 is conveyed by the second conveyor unit 70 toward the forward belt conveyor 64.

[0050] Before the conveying tray 4 is transferred from the second conveying unit 70 to the forward belt conveyor 64, the second conveying unit 70 is stopped once. Subsequently, the articulated arm 88 of the transfer unit 12 is driven, and the wafer 30 accommodated in the conveying tray 4 on the second conveying unit 70 is held by suction by the suction piece 90. Then, the wafer 30 held by the suction piece 90 is conveyed out of the conveying tray 4, and the wafer 30 is transferred to the cassette 8 on the cassette tray 10. In this case, the wafer 30 is transferred to the cassette 8 provided with the same identification mark 34 as the identification mark 34 of the conveying tray 4.

[0051] Subsequently, the second transfer unit 70 is actuated to transfer the conveying tray 4 from the second transfer unit 70 to the forward belt conveyor 64, after which the conveying tray 4 is conveyed by the forward belt conveyor 64 in the Y1 direction Y1 to a position opposite the ingot grinding unit 40. In this case, the first conveying tray stopper 72 is lifted, thereby stopping the conveying tray 4 at a position opposite the ingot grinding unit 40. Subsequently, the link arm 82 of the first moving mechanism 76 is driven, and the ingot 24 on the conveying tray 4 is held by the suction piece 84 under suction. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the conveying tray 4 to the holding table 46 of the ingot grinding unit 40.

[0052] After the third conveying step is performed, an ingot grinding step is performed in the ingot grinding unit 40 in which the ingot 24 with the wafer 30 detached therefrom is sucked off the holding table 46, and the upper surface (separation surface) of the ingot 24 held by the holding table 46 under sucking is ground to planarize the upper surface.

[0053] After the ingot grinding step has been performed, a fourth conveying step is performed in which the ingot 24 with its upper surface planarized by the ingot grinding unit 40 is conveyed to the laser deposition unit 42.

[0054] In the fourth conveying step, first, the articulated arm 82 of the first moving mechanism 76 is driven, the ingot 24 is held on the holding table 46 by the suction piece 84 under suction, and the suction force of the holding table 46 is released. Subsequently, the ingot 24 held by the suction piece 84 under suction is moved from the holding table 46 to the first ingot receiving section 22a of the conveying tray 4.

[0055] Subsequently, the conveyor tray 4 is conveyed by the forward belt conveyor 64 in the Y1 direction to a position opposite the laser deposition unit 42. Subsequently, the articulated arm 82 of the second moving mechanism 78 is driven, and the ingot 24 is held on the conveyor tray 4 by the suction piece 84 under suction. Subsequently, the ingot 24, held by the suction piece 84 under suction, is moved from the conveyor tray 4 onto the holding table 52 of the laser deposition unit 42.

[0056] After the fourth conveying step is performed, the aforementioned release layer forming step is performed at the laser deposition unit 42. Then, the release layer forming step, the wafer releasing step, the ingot grinding step, and the second to fourth conveying steps are repeatedly performed, whereby the wafers 30 are formed in the number that can be formed from the ingot 24, and the wafers 30 are housed in the cassette 8 provided with the same identification mark 34" as the identification mark 34 provided on the conveying tray 4.

[0057] In the present embodiment, each step performed by the wafer forming apparatus has been described considering a single ingot 24. After the first conveying step of conveying the ingot 24 from the conveying tray 36 to the laser deposition unit 42 is performed, the first conveying step is repeatedly performed at an appropriate interval, and the release layer forming step, the wafer peeling step, the ingot grinding step, and the second to fourth conveying steps are simultaneously repeatedly performed for a plurality of ingots 24, whereby the wafers 30 can be formed in an amount in which the wafers 30 can be formed from the plurality of ingots.

[0058] Furthermore, in the wafer forming apparatus 2, the conveying tray 4 is provided with the identification mark 34, and the cassette tray 10 or the cassette 8 corresponding to the conveying tray 4 is provided with the same identification mark 34' or 34" as the identification mark 34 of the conveying tray 4. Therefore, even in the case where an operation interruption or a failure occurs and the operation of the wafer forming apparatus 2 is stopped, the wafer 30 can be securely accommodated in the cassette 8 associated with the ingot 24, and the parent-child relationship between the ingot 24 and the wafer 30 is not broken but is always clear.

[0059] 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 encompassed by the invention.

Claims

[1] Wafer forming apparatus (2) for forming a wafer (30) from a semiconductor ingot (24), the wafer forming apparatus (2) comprising: a conveyor tray (4) with an ingot receiving section (22) which receives the semiconductor ingot (24) and a wafer receiving section (28) which receives the wafer (30) formed from the semiconductor ingot, a belt conveyor unit (6) which conveys the conveyor tray (4) to each processing device, a cassette tray (10) on which cassettes (8) holding the wafers are arranged corresponding to the conveyor trays (4), and a transfer unit (12) which transfers the wafer from the wafer receiving section (28) of the conveyor tray to the cassette (8) arranged on the cassette tray (10), wherein the conveyor tray (4) is provided with an identification marking (34) and the cassette tray (10) or the cassette (8) corresponding to the conveyor tray (4) is provided with the same identification marking (34', 34") as the identification marking (34) provided on the conveyor tray. [2] The wafer forming apparatus (2) according to claim 1, wherein the identification mark (34) is a color, a symbol, a character, a numeral, a pattern, or an image, or a combination thereof.

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