CARRIER STORAGE

Abstract

A carrier tray (2) for use in a wafer forming apparatus for forming a wafer from a semiconductor ingot, the carrier tray (2) comprising: a housing (4) including an upper wall (10), a lower wall (12), a pair of side walls (14) connecting the upper wall and the lower wall, and a tunnel (16) formed by the upper wall (10), the lower wall (12) and the pair of side walls (14); an ingot receiving recess (6) formed in the upper wall (10) of the housing (4) and receiving the semiconductor ingot; a wafer receiving recess (8) formed in the bottom wall (12) of the housing (4) and receiving a wafer; wherein the ingot receiving recess (6) includes a first ingot receiving recess (6a) and a second ingot receiving recess (6b) which are concentric with each other and correspond to two sizes of semiconductor ingots, and a plurality of levers (22), each having a first application point (24a) protruding from a lower surface of the first ingot receiving recess (6a), a second application point (24b) protruding from a lower surface of the second ingot receiving recess (6b), a first action point (26a) protruding from a side surface of the first ingot receiving recess (6a), a second action point (26b) protruding from a side surface of the second ingot receiving recess (6b), and a pivot point (28), each lever (22) being attached to the housing (4) so ​​that it can be rotated about the pivot point (28), wherein, when the semiconductor ingot is received in the first or second ingot receiving recess (6a, 6b), the first or second application point (24a, 24b) of the lever (22) is actuated by the weight of the semiconductor ingot itself, and a side surface of the semiconductor ingot is supported by the first or second action point (26a, 26b) of the lever (22).

Description

BACKGROUND OF THE INVENTIONTechnical field

[0001] The present invention relates to a carrier tray used in 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 on a functional layer stacked on a front surface of a wafer, which includes a material made of silicon (Si), sapphire (Al2O3), or the like, in respective regions divided by a plurality of intersecting streets. In addition, power devices, LEDs, and the like are formed on a functional layer stacked on a front surface of a wafer, which includes a material made of single-crystal silicon carbide (SiC), in respective regions divided by a plurality of intersecting streets.The wafer formed with the components is subjected to processing along the streets by a cutting device and a laser processing device and divided into individual component chips, and the component chips are used in electrical equipment such as mobile phones and personal computers.

[0003] The wafer to be formed with the devices is generally formed by cutting a cylindrical ingot into a thin shape by a band saw.

[0004] A front surface and a back surface of the thus-cut wafer are polished and finished as a mirror surface (see, for example, Japanese Patent Laid-Open No. 2000-94221). However, if the ingot is cut by a band saw and the thus-cut front surface and back surface of the wafer are polished, most of the ingot (70% to 80%) is discarded, which is not economical. In particular, a single-crystal SiC ingot is so hard that it is difficult to cut the ingot by a band saw and it takes a considerable amount of time, resulting in low productivity and high unit costs. Accordingly, there is a problem that wafers must be manufactured efficiently.

[0005] In view of the above, a technology has been proposed in which a laser beam of such a wavelength that it can be transmitted through the single-crystal SiC is applied to a single-crystal SiC ingot, the focal point of the laser beam is positioned in the single-crystal SiC ingot to form a release layer at a planned dividing plane, and a wafer is peeled off from the single-crystal SiC ingot along the planned dividing plane in which the release layer was formed (see, for example, Japanese Patent Laid-Open No. 2019-106458). PRESENTATION OF THE INVENTION

[0006] In the wafer forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2019-106458, the ingot and the wafer detached therefrom are carried between units such as an ingot grinding unit and a laser deposition unit in the state of being placed on a carrier tray. However, the carrier tray has a problem that the ingot is unstable with respect to the carrier tray when the ingot is transported while being supported by an ingot support section, and the ingot may fall from the carrier tray.

[0007] JP H10-74816 A discloses a carrier tray with multiple levers.

[0008] Accordingly, it is an object of the present invention to provide a carrier tray which can stably hold an ingot and prevent the ingot from falling during carrying the ingot.

[0009] In accordance with one aspect of the present invention, there is provided a carrier tray according to claim 1 which can be used in a wafer forming apparatus for forming a wafer from a semiconductor ingot.The carrier tray includes: a housing including an upper wall, a lower wall, a pair of side walls connecting the upper wall and the lower wall, and a tunnel formed by the upper wall, the lower wall, and the pair of side walls; an ingot receiving recess received in the upper wall of the housing and receiving the ingot; a wafer receiving recess formed in the lower wall of the housing and receiving a wafer; and a plurality of levers each having an application point protruding from a lower surface of the ingot receiving recess, an action point protruding from a side surface of the ingot receiving recess, and a pivot point formed between the application point and the action point, each of the levers being mounted on the housing so as to be able to rotate about the pivot point.When the semiconductor ingot is received in the ingot receiving cavity, the application points of the levers are actuated by a weight of the semiconductor ingot itself and a side surface of the semiconductor ingot is supported by the points through the action of the levers.

[0010] Preferably, the ingot receiving cavity includes more than two receiving cavities that are concentric and correspond to multiple sizes of semiconductor ingots.

[0011] According to the present invention, since the application points are actuated by the weight of the ingot itself and the side surfaces of the ingot are supported by the action points, the ingot can be held stably and prevented from falling off during carrying of the ingot.

[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 carrier tray according to an embodiment of the present invention; Fig. 2 is a front view of a lever used in Fig. 1 is shown; Fig. 3A is a sectional view of the carrier tray shown in Fig. 1, in a state where a large-diameter ingot is positioned at an upper side of an ingot receiving recess; Fig. 3B is a sectional view of the carrier tray shown in Fig. 1, in a state where the large-diameter ingot is supported in the ingot receiving recess; Fig. 4A is a sectional view of the carrier tray shown in Fig. 1, in a state where a small-diameter ingot is positioned at an upper side of the ingot receiving recess; Fig. 4B is a sectional view of the carrier tray shown in Fig. 1, in a state where the small diameter ingot is supported in the ingot receiving recess; Fig. 5 is a front view of a lever according to a modification; Fig. 6 is a perspective view of a wafer forming apparatus in which the carrier tray shown in Fig. 1 is used; and Fig. 7 is a perspective view of a portion of the wafer forming apparatus shown in Fig. 6 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] A carrier tray according to a preferred embodiment of the present invention will be described below with reference to the figures. A carrier tray, which is designated as a whole by reference numeral 2 in Fig. 1 includes a housing 4, an ingot receiving recess 6 which receives a semiconductor ingot (hereinafter simply referred to as an ingot), and a wafer receiving portion 8 which receives a wafer.

[0014] The housing 4 includes a rectangular upper wall 10, a rectangular lower wall 12 arranged on a lower side of the upper wall 10, a pair of rectangular side walls 14 connecting the upper wall and the lower wall 12, and a tunnel 16 formed by the upper wall 10, the lower wall 12 and the pair of side walls 14.

[0015] As in Fig. 1, the ingot receiving recess 6 is formed in an upper surface of the top wall 10 of the casing 4. The ingot receiving recess 6 in the present embodiment includes an annular first ingot receiving recess 6a recessed downward from the upper surface of the top wall 10, and a circular second ingot receiving recess 6b smaller in diameter than the first ingot receiving recess 6a and recessed further downward compared to the first ingot receiving recess 6a. The first ingot receiving recess 6a and the second ingot receiving recess 6b are concentrically formed.

[0016] The diameter of the first ingot receiving recess 6a is slightly larger (on the order of several millimeters) than the diameter of a cylindrical ingot 18 having a comparatively large diameter (for example, a 6-inch diameter), and the ingot 18 having a comparatively large diameter is received in the first ingot receiving recess 6a. The diameter of the second ingot receiving recess 6b is slightly larger than that of the cylindrical ingot 20 having a comparatively small diameter (for example, a 4-inch diameter), and the ingot 20 having a comparatively small diameter is received in the second ingot receiving recess 6b.

[0017] Accordingly, in the present embodiment, the ingot receiving recess 6 includes the concentric first and second ingot receiving recesses 6a and 6b corresponding to the two sizes of the ingots 18 and 20. Note that the ingot receiving recess 6 may be a single circular recess corresponding to one size of an ingot, or may include a plurality of concentric receiving recesses corresponding to three or more sizes of ingots.

[0018] With reference to Fig. 1 to 3, a plurality of levers 22 (four in the present embodiment) are arranged in the carrier tray 2 at intervals in a circumferential direction of the ingot receiving recess 6. Each of the levers 22 has an application point 24 protruding from a lower surface of the ingot receiving recess 6, an action point 26 protruding from a side surface of the ingot receiving recess 6, and a pivot point 28 formed between the application point 24 and the action point 26.

[0019] As with reference to Fig. 3A and Fig. 3B, each lever 22 is disposed in a receiving hole 30 formed in the housing 4 corresponding to the shape of the lever 22, and is rotatably mounted on the housing 4 by a pin (the reference numeral is omitted) penetrating through the pivot point 28.

[0020] As in Fig. 2, Fig. 3A and Fig. 3B, the lever 22 in the present embodiment includes a first portion 22a extending upward from the pivot point 28, a second portion 22b extending inward in a radial direction of the ingot receiving recess 6 from an upper end of the first portion 22a, a third portion 22c extending inward in the radial direction of the ingot receiving recess 6 from the pivot point 28, a fourth portion 22d extending upward from the third portion 22c between a radially outer end portion and a radially inner end portion of the third portion 22c, a fifth portion 22e extending radially inward in the radial direction from the fourth portion 22d between an upper end and a lower end of the fourth portion 22d, and a sixth portion 22f.which extends upwards from the radially inner end part of the third section 22c.,

[0021] The application point 24 of the lever 22 in the present embodiment includes a first application point 24a formed from an upper end of the fourth portion 22d protruding from a lower surface of the first ingot receiving recess 6a, and a second application point 24b formed from an upper end of the sixth portion 22f protruding from a lower surface of the second ingot receiving recess 6b.The action point 26 of the lever 22 in the present embodiment includes a first action point 26a formed from an inner end part in the radial direction of the second portion 22b that protrudes (can protrude) from a side surface of the first ingot receiving recess 6a, and a second action point 26b formed from a radially inner end part of the fifth portion 22e that protrudes (can protrude) from a side surface of the second ingot receiving recess 6b.

[0022] The lever 22 is pivotable about the pivot point 28 between a support position, at which a side surface of the ingot is supported by the action point 26, and a release position, at which the support of the ingot is released. As shown in Fig. 3A, at the release position, the first application point 24a protrudes from the lower surface of the first ingot receiving recess 6a and the second application point 24b protrudes from the lower surface of the second ingot receiving recess 6b, wherein the first action point 26a does not protrude from the side surface of the first ingot receiving recess 6a and the second action point 26b does not protrude from the side surface of the second ingot receiving recess 6b.

[0023] As in Fig. As shown in Fig. 3A, the carrier tray 2 in the present embodiment has a positioning means 32 additionally provided on the housing 4 for positioning the lever 22 at the release position in the case where the ingot 18 or 20 is not accommodated in the first or second ingot accommodation recess 6a or 6b. The positioning means 32 in the present embodiment includes a coil spring disposed in a hole 34 formed in the housing 4 so as to extend in the radial direction, one side end part of the coil spring being connected to the first portion 22a of the lever 22, and an end part of another side of the coil spring being connected to a side surface of the hole 34.

[0024] Furthermore, with reference to Fig. 3A and Fig. 3B, when the ingot 18 having a large diameter is received in the first ingot receiving recess 6a, the first application point 24a of the lever 22 is pressed by the ingot 18 and moved downward, as shown in Fig. 3B. In other words, the first application point 24a is actuated by the weight of the ingot 18 itself. Then, the lever is pivoted about the pivot point 28 to the support position by overcoming the force of the positioning means 32, and the first action point 26a of the lever 22 protrudes from the side surface of the first ingot receiving recess 6a to support the side surface of the ingot 18. In the support tray 2, therefore, the ingot 18 can be stably held while supporting the ingot 18, so that the ingot 18 can be prevented from falling. Note, while any number of levers 22 may be provided, it is preferable to provide three or more levers so that the ingot 18 is stably held.

[0025] With reference to Fig. 4A and Fig. 4B, when the ingot 20 with a small diameter is received in the second ingot receiving recess 6b, the second application point 24b is supported by the weight of the ingot 20 itself, as shown in Fig. 4B, the lever 22 is actuated (moved downward). Then, the lever 22 is pivoted about the pivot point 28 to the support position by overcoming the force of the positioning means 32, and the second action point 26b of the lever 22 protrudes from the side surface of the second ingot receiving recess 6b to support the side surface of the ingot 20. Consequently, the support tray 2 has the levers 22 corresponding to the sizes of the ingots 18 and 20 and can stably hold the ingots 18 and 20.

[0026] On the other hand, when the ingot 18 or 20 is removed from the first or second ingot receiving recess 6a or 6b, the weight of the ingot 18 or 20 does not act on the first or second application point 24a or 24b (anymore) and therefore the lever 22 is pivoted about the pivot point 28 to the release position by the positioning means 32.

[0027] Note that the positioning means 32 that applies a force to the lever 22 toward the release position includes the coil spring in the present embodiment, but the coil spring is not limiting in that a force is applied to the lever 22 toward the release position to such an extent that the lever 22 can swing when the ingot 18 or 20 is received in the first or second ingot receiving recess 6a or 6b, and the first or second action point 26a or 26b can support the side surface of the ingot 18 or 20. The material of the positioning means 32 can be a metal, a synthetic rubber, a synthetic plastic, or the like.

[0028] For example, in the case where a position of the center of gravity of the lever 22 and a position of the pivot point 28 are appropriately adjusted so that the lever 22 is positioned at the release position when the ingots 18 and 20 are not accommodated in the first and second ingot accommodating recesses 6a and 6b, the positioning means need not be additionally provided on the housing 4.

[0029] While the levers 22 described above correspond to the sizes of both ingots 18 and 20, a plurality of first levers 36a corresponding to the ingot 18 and a plurality of second levers 36b corresponding to the size of the ingot 20 may be arranged in the housing 4 at intervals in the circumferential direction, as shown in Fig. 5 shown.

[0030] Although not shown, a configuration may be adopted in which, when the ingot 18 is received in the first ingot receiving recess 6a, a first application point 38a is actuated (the first lever 36a is rotated about a first pivot point 40a) by the weight of the ingot 18 itself and a first action point 42a supports the side surface of the ingot 18, and, when the ingot 20 is received in the second ingot receiving recess 6b, a second application point 38b is actuated (the second lever 36b is pivoted about a second pivot point 40b) by the weight of the ingot 20 itself and a second action point 42b supports the side surface of the ingot 20.

[0031] In addition, in the case where the ingot receiving recess 6 is a single circular receiving recess corresponding to one size of the ingot, levers are arranged corresponding to one size of the ingot, and in the case where the ingot receiving recess 6 is concentric receiving recesses corresponding to three or more sizes of the ingots, levers may be arranged corresponding to three or more sizes of the ingots.

[0032] As in Fig. As shown in Figure 1, the wafer receiving portion 8 is formed in an upper surface of the bottom wall of the casing 4. The wafer receiving portion 8 in the present embodiment includes an annular first wafer receiving portion 8a recessed downward from the upper surface of the bottom wall 12, and a circular second wafer receiving portion 8b smaller in diameter than the first wafer receiving portion 8a and recessed further downward than the first wafer receiving portion 8a. The first wafer receiving portion 8a and the second wafer receiving portion 8b are concentrically formed.

[0033] The diameter of the first wafer receiving portion 8a is slightly larger than that of a disc-shaped wafer having a relatively large diameter (for example, a 6-inch diameter), and a wafer having a relatively large diameter is received in the first wafer receiving portion 8a. The diameter of the second wafer receiving portion 8b is slightly larger than that of a disc-shaped wafer having a relatively small diameter (for example, a 4-inch diameter), and a wafer having a relatively small diameter is received in the second wafer receiving portion 8b.

[0034] Thus, in the present embodiment, the wafer receiving section 8 includes the concentric first and second wafer receiving sections 8a and 8b corresponding to the two wafer sizes. Note that the wafer receiving section 8 may be a single circular receiving section corresponding to one wafer size or may include multiple concentric receiving sections corresponding to three or more wafer sizes.

[0035] Fig. 6 and Fig. 7 illustrates a wafer forming apparatus 50 using the carrier tray 2 described above. The wafer forming apparatus 50 for forming a wafer from an ingot includes: an ingot grinding unit 52; a laser deposition unit 54; a wafer detachment unit 56; a belt conveyor unit 58 that carries the ingot carried by the carrier tray 2 to the ingot grinding unit 52, the laser deposition unit 54, and the wafer detachment unit 56; a carrier tray storage 60; a cassette storage 64 in which a plurality of cassettes 62 that hold wafers detachable from the ingot are stored; and a receiving means 66 that carries the carrier tray 2 in the carrier tray warehouse 60 to the belt conveyor unit 58 and receives the wafers carried in the wafer receiving section 8 of the carrier tray 2 into the cassette 62 in the cassette warehouse 64.

[0036] As in Fig. As shown in Fig. 7, the ingot grinding unit 52 includes a holding table 68 that holds the ingot under suction and is rotatable, and an abrasive 70 that grinds an upper surface of the ingot held under suction by the holding table 68 to make the surface flat. The abrasive 70 has a grinding wheel 72 that includes grinding stones (not shown) and is rotatable. The ingot grinding unit 52 brings the grinding stones into contact with the upper surface of the ingot while rotating the holding table 68 that holds the ingot under suction and rotating the grinding wheel 72, thereby grinding the upper surface of the ingot and making the upper surface flat.

[0037] The laser deposition unit 54 includes a holding table 74 that holds the ingot under suction and is movable and rotatable in an X-axis direction, and a laser deposition means 76 that applies a laser beam to the ingot held under suction by the holding table 74. The laser deposition means 76 has a light collector 78 that collects a pulsed laser beam emitted by a laser oscillator (not shown) to apply the pulsed laser beam to the ingot, and is movable in the Y-axis direction.

[0038] The laser application unit 54 applies a laser beam of such a wavelength as to be transmitted through the ingot while applying a focal point of the laser beam at a depth corresponding to a thickness of a wafer to be formed from the upper surface of the ingot, while the holding table 74 holding the ingot under suction is moved in the X-axis direction or while the light collector 78 is moved in the Y-axis direction, to thereby form a release layer whose strength is lowered in the ingot.

[0039] The wafer detaching unit 56 includes a holding table 80 that holds the ingot under suction and can be moved in the X-axis direction, a liquid tank body 82 that forms a liquid collecting space together with the holding table 80, and an ultrasonic vibration generating element 84 that applies ultrasonic vibration to the ingot held under suction by the holding table 80 and holds a wafer, which is detached from the ingot, under suction.

[0040] The wafer detaching unit 56 actuates the ultrasonic vibration generating element 84 to apply ultrasonic vibration to the ingot after a liquid is held in the liquid holding space formed by the holding table 80 holding the ingot under suction and the liquid tank body 82, to thereby detach the wafer from the ingot with the detaching layer as a starting point.

[0041] The belt conveyor unit 58 includes a forward belt conveyor 86 that carries the carrier tray 2 in a Y1 direction, a reverse belt conveyor 88 that carries the carrier tray 2 in a Y2 direction (a direction opposite to the Y1 direction), a first carrying means 90 that carries the carrier tray 2 from an end point of the forward belt conveyor 86 to a start point of the reverse belt conveyor 88 and stops the carrier tray 2 carried by the forward belt conveyor 86 at a position facing the wafer detaching unit 56, and a second carrying means 92 that carries the carrier tray 2 from an end point of the reverse belt conveyor 88 to a start point of the forward belt conveyor 86.

[0042] In addition, the belt conveyor unit 58 includes a vertically movable first carrier tray stopper 94 that stops the carrier tray 2 conveyed by the forward belt conveyor 86 at a position facing the ingot grinding unit 52, and a vertically movable second carrier tray stopper 96 that stops the carrier tray 2 conveyed by the forward belt conveyor 86 at a position facing the laser deposition unit 54.

[0043] Further, the belt conveying unit 58 includes a first transfer means 98 that transfers the ingot between the carrier tray 2 stopped by the first carrier tray stopper 94 and the ingot grinding unit 52, a second transfer means 100 that transfers the ingot between the carrier tray 2 stopped by the second carrier tray stopper 96 and the laser deposition unit 54, and a third transfer means 102 that transfers the ingot between the carrier tray 2 stopped by the first transfer means 90 and the wafer detaching unit 96, and transfers the wafer detached from the ingot from the wafer detaching unit 56 to the carrier tray 2.

[0044] Each of the first, second, and third transfer means 98, 100, and 102, which have a common configuration, includes an articulated boom 104 that can be moved in the X-axis direction, the Y-axis direction, and a Z-axis direction, and a suction piece 106 attached to a tip end of the articulated boom so that it can be inverted from top to bottom. A one-sided surface of the suction piece 106 is formed with a plurality of suction holes (not shown) connected to a suction means (not shown).

[0045] With reference to Fig. 6, the carrier tray storage 60 in the present embodiment has four receiving sections 108 extending in the X-axis direction. In the carrier tray storage 60, the carrier tray 2 can be accommodated from this side in the X-axis direction in Fig. 6 can be received in one of the receiving sections 108 and the carrier tray 2 in the receiving section 108 can be moved from the depth side in the X-axis direction into Fig. 6 can be removed.

[0046] As in Fig. 6, the cassette storage 64 in the present embodiment has 16 receiving sections 116 projecting in the Y-axis direction, and the cassette 62, which receives the wafers detached from the ingot, is received in each of the receiving sections 110. In the cassette storage 64, the cassette 62 can be placed in the receiving sections 110 from this side in the Y-axis direction. Fig. 6 and the wafers can be loaded in the cassette 62 in the loading section 110 from the depth side in the Y-axis direction in Fig. 6 can be recorded.

[0047] As in Fig. As shown in Figure 7, the receiving means 66 includes an articulated boom 112 that can be moved in the X-axis, Y-axis, and Z-axis directions, and a suction pad 114 mounted at a tip end of the articulated boom 112 so that it can be turned upside down. A one-sided surface of the suction pad 114 is formed with a plurality of suction holes (not shown) connected to suction means (not shown).

[0048] At the time of forming a wafer from an ingot by the wafer forming apparatus 50 as shown in Fig.6, first, one or more ingots (four large-diameter ingots 18 in the present embodiment) are prepared. Next, each of the ingots 18 is received in the first ingot receiving recess 6a of the carrier tray 2, and a side surface of the ingot 18 is supported by the first action points 26a so that the ingot 18 cannot fall from the carrier tray 2 while the ingot 18 is supported by the wafer forming apparatus 50. Subsequently, the carrier trays 2 supporting the ingots 18 are received in the receiving sections 108 of the carrier tray stocker 60.

[0049] Next, a first carrying step is performed for carrying the ingot 18 from the carrier support warehouse 60 to the laser deposition unit 54. Generally, the ingot has an end surface formed flat so that it does not obstruct the incidence of the laser beam in a release layer forming step, which will be described later. Therefore, in the present embodiment, an example of carrying the ingot 18 from the carrier support warehouse 60 to the laser deposition unit 54 in the first carrying step will be described in the present embodiment. In the case where the end surface of the ingot 18 is not formed flat to such an extent that it does not obstruct the incidence of the laser beam in the release layer forming step, the ingot 18 can be carried from the carrier support warehouse 60 to the ingot grinding unit 52 in the first carrying step.

[0050] In the first carrying step, first, the articulated boom 112 of the receiving means 66 is driven, and the suction piece 114, with the suction holes facing upward, is inserted into the tunnel 116 of the carrier tray 2. Next, the suction piece 114 is slightly moved upward in the tunnel 16, and a lower surface of the upper wall 110 of the carrier tray 2 is held under suction by the suction piece 114. Thereafter, the carrier tray 2, held under suction by the suction piece 114, is carried from the carrier tray storage 60 onto the forward belt conveyor 86.

[0051] After the carrier tray 2 is placed on the forward belt conveyor 86, the carrier tray 2 is carried in the Y1 direction by the forward belt conveyor 86 to the position facing the laser deposition unit 54. In this case, the first carrier tray stopper 94 is lowered and the second carrier tray stopper 96 is raised, so that the carrier tray 2 is stopped at the position facing the laser deposition unit 54.

[0052] Next, the articulated arm 104 of the second transfer means 100 is driven, and the ingot 18 on the carrier tray 2 is held under suction by the suction piece 106. Subsequently, the ingot 18, held under suction by the suction piece 106, is transferred from the carrier tray 2 to the holding table 74 of the laser deposition unit 54. Note that when the ingot 18 is lifted from the first ingot receiving recess 6a, the weight of the ingot 18 no longer acts on the first application points 24a, and therefore, each lever 22 is pivoted about the pivot point 28 to the release position by the positioning means 32.

[0053] After the first support step is performed, the release layer forming step of holding the ingot 18 under suction by the holding table 74 and applying a laser beam of such a wavelength that can be transmitted through the ingot 18 is positioned on the ingot 18 with the focus point of the laser beam at a depth corresponding to the thickness of the wafer to be formed from the upper surface of the ingot 18 held under suction by the holding table 74, to thereby form the release layer in the laser deposition unit 54.

[0054] After the release layer forming step is performed, a second carrying step is performed for carrying the ingot 18 formed with the release layer from the laser deposition unit 54 to the wafer detachment unit 56. In the second carrying step, first, the articulated boom 104 of the second transfer means 100 is driven, and the ingot 18 is held on the holding table 74 under suction by the suction piece 106, and the suction force of the holding table 74 is released. Next, the ingot 18 held under suction by the suction piece 106 is transferred from the holding table 74 to the first ingot receiving recess 6a of the carrier tray 2.

[0055] Subsequently, the carrier tray 2 is carried in the Y1 direction by the forward belt conveyor 86 to the position facing the wafer detachment unit 56. In this case, the carrier tray 2 is stopped at the position facing the wafer detachment unit 56 by the first carrying means 90. Next, the articulated boom 104 of the third transfer means 102 is driven, and the ingot 18 on the carrier tray 2 is held under suction by the suction piece 106. Subsequently, the ingot 18 held under suction by the suction piece 106 is transferred from the carrier tray 2 to the holding table 80 of the wafer detachment unit 56.

[0056] After the second support step is performed, a wafer detaching step of holding the ingot 18 formed with the release layer under suction by the holding table 80 and holding the upper surface of the ingot 18 held under suction by the holding table 80 and detaching the wafer from the ingot 18 with the release layer as a starting point is performed at the wafer detaching unit 56.

[0057] After the wafer detaching step is performed, a third carrying step is performed for carrying the wafer (not shown) detached from the ingot 18 from the wafer detaching unit 56 into the cassette 62 in the cassette storage 64 and carrying the ingot 18 from which the wafer has been detached from the wafer detaching unit 56 to the ingot grinding unit 52.

[0058] In the third support step, first, the articulated boom 104 of the third transfer means 102 is driven, and the wafer detached from the ingot 18 is held under suction by the suction piece 106. Next, the wafer, held under suction by the suction piece 106, is picked up by the wafer detachment unit 56 into the wafer receiving section 8a of the carrier tray 2.

[0059] Subsequently, the articulated arm 104 of the third transfer means 102 is driven, the ingot 18 is held on the holding table 80 under suction by the suction piece 106, and the suction force of the holding table 80 is released. Next, the ingot 18, held under suction by the suction piece 106, is transferred from the holding table 80 into the first ingot receiving recess 6a of the carrier tray 2.

[0060] Subsequently, the carrier tray 2 carrying the ingot 18 and the wafer is carried from the forward belt conveyor 86 to the reverse belt conveyor 88 by the first carrying means 90. Next, the carrier tray 2 is carried in the Y2 direction by the reverse belt conveyor 88, and the carrier tray 2 is transferred to the second carrying means 92. Subsequently, the carrier tray 2 is carried to the forward belt conveyor 86 by the second carrying means 92.

[0061] The second support means 92 is stopped once before the carrier tray 2 is transferred from the second support means 92 to the forward belt conveyor 86. Next, the articulated boom 112 of the pick-up means 66 is driven, and the wafer supported by the carrier tray 2 on the second support means 92 is held under suction by the suction piece 114. Then, the wafer held under suction by the suction piece 114 is removed from the carrier tray 2, and the wafer is received in the cassette 62 of the cassette storage 64.

[0062] Subsequently, the second carrying means 92 is actuated to move the carrier tray 2 from the second carrying means 92 onto the forward belt conveyor 86, whereupon the carrier tray 2 is moved in the Y1 direction by the forward belt conveyor 86 to the position facing the ingot grinding unit 52. In this case, the first carrier tray stopper 94 is lifted, and the carrier tray 2 is stopped at the position facing the ingot grinding unit 52. Next, the articulated boom 104 of the first transfer means 98 is driven, and the ingot 18 on the carrier tray 2 is held under suction by the suction piece 106. Subsequently, the ingot 18 held under suction by the suction piece 106 is transferred from the carrier tray 2 to the holding table 86 of the ingot grinding unit 52.

[0063] After the third support step is performed, an ingot grinding step of holding the ingot 18 from which the wafer has been detached under suction by the holding table 68 and grinding the upper surface (detachment surface) of the ingot 18 under suction by the holding table 68 to make the upper surface flat is performed at the ingot grinding unit 52.

[0064] After the ingot grinding step is performed, a fourth supporting step of supporting the ingot 18 having the upper surface flattened by the ingot grinding unit 52 to the laser deposition unit 54 is performed.

[0065] In the fourth support step, first, the articulated boom 104 of the first transfer means 98 is driven, the ingot 18 is held on the holding table 68 under suction by the suction piece 106, and the suction force of the holding table 68 is released. Next, the ingot 18, held under suction by the suction piece 106, is transferred from the holding table 68 into the first ingot receiving recess 6a of the support tray 2.

[0066] Subsequently, the carrier tray 2 is carried in the Y1 direction by the forward belt conveyor 86 to the position where it faces the laser deposition unit 54. Next, the articulated boom 104 of the second transfer means 100 is driven, and the ingot 18 on the carrier tray 2 is held under suction by the suction piece 106. Subsequently, the ingot 18 held under suction by the suction piece 106 is transferred from the carrier tray 2 to the holding table 74 of the laser deposition unit 54.

[0067] After the fourth support step is performed, the above-described release layer formation step is performed at the laser deposition unit 54. Then, the release layer formation step, the wafer release step, the ingot grinding step, and the second to fourth support steps are repeated to form a number of wafers that can be formed from the ingot 18, and the wafers are accommodated in the cassette 62 in the cassette storage 64.

[0068] In the present embodiment, each step performed by the wafer forming apparatus 50 has been described with reference to a single ingot. However, after the first support step of supporting the ingot 18 from the carrier tray stock 60 to the laser deposition unit 54 is performed, the first support step may be repeated, and the release layer forming step, the wafer releasing step, the ingot grinding step, and the second to fourth support steps may be repeated in parallel for a plurality (for example, four) ingots 18, so that a number of wafers formed from the plurality of ingots 18 can be obtained.

[0069] As described above, in the carrier tray 2 in the present embodiment used in the wafer forming apparatus 50 described above, the application points 24 are actuated (moved downward) by the weight of the ingot itself, and the action points 26 support the side surface of the ingot, therefore the ingot can be stably held and prevented from falling off while the ingot is supported.

Claims

[1] A carrier tray (2) for use in a wafer forming apparatus for forming a wafer from a semiconductor ingot, the carrier tray (2) comprising: a housing (4) including an upper wall (10), a lower wall (12), a pair of side walls (14) connecting the upper wall and the lower wall, and a tunnel (16) formed by the upper wall (10), the lower wall (12) and the pair of side walls (14); an ingot receiving recess (6) formed in the upper wall (10) of the housing (4) and receiving the semiconductor ingot; a wafer receiving recess (8) formed in the bottom wall (12) of the housing (4) and receiving a wafer; wherein the ingot receiving recess (6) includes a first ingot receiving recess (6a) and a second ingot receiving recess (6b) which are concentric with each other and correspond to two sizes of semiconductor ingots, and a plurality of levers (22), each having a first application point (24a) protruding from a lower surface of the first ingot receiving recess (6a), a second application point (24b) protruding from a lower surface of the second ingot receiving recess (6b), a first action point (26a) protruding from a side surface of the first ingot receiving recess (6a), a second action point (26b) protruding from a side surface of the second ingot receiving recess (6b), and a pivot point (28), each lever (22) being attached to the housing (4) so ​​that it can be rotated about the pivot point (28), wherein, when the semiconductor ingot is received in the first or second ingot receiving recess (6a, 6b), the first or second application point (24a, 24b) of the lever (22) is actuated by the weight of the semiconductor ingot itself, and a side surface of the semiconductor ingot is supported by the first or second action point (26a, 26b) of the lever (22). [2] The carrier tray (2) according to claim 1, wherein the ingot receiving recess (6) includes more than two ingot receiving recesses (6a, 6b) which are concentrically formed and correspond to a plurality of sizes of semiconductor ingots.

Images