Processing system

Abstract

The present invention aims to flatten the grinding surface after grinding to remove at least a portion of the damage caused by grinding. The grinding device conveys the wafer from the first rough grinding unit and the first finishing grinding unit to the first laser beam irradiation unit by means of a turntable. Because of this, the wafer can be ground within a single grinding device, and damage to the wafer caused by grinding can be easily and quickly repaired. Therefore, it is possible to efficiently and effectively perform the grinding of the wafer and the repair of damage.

Description

Technology Field

[0001] The present invention relates to a processing system for thinning a workpiece. Background Technology

[0002] As disclosed in Patent Document 1, it is common practice to perform grinding with a grinding pad after grinding a workpiece in order to flatten the surface irregularities and remove grinding marks or damage caused by grinding. Prior art literature

[0003] [Patent Document 1] Japanese Patent Publication No. 2005-153090 The problem to be solved

[0004] Accordingly, the object of the present invention is to provide a processing system capable of removing at least a portion of the damage caused by grinding by flattening the grinding surface after grinding. means of solving the problem

[0005] According to the present invention, a workpiece processing system is provided, comprising: a grinding unit for grinding a workpiece, the grinding wheel and a spindle that rotatably supports the grinding wheel; an energy supply unit for supplying energy to the grinding surface of the workpiece ground by the grinding unit to melt and repair at least a portion of the damage caused by grinding; and a conveying unit for conveying the workpiece from the grinding unit to the energy supply unit.

[0006] Preferably, the energy supply unit comprises a laser oscillator that emits a laser beam and a focusing lens that focuses the laser beam, and is a laser beam irradiation unit that irradiates a laser beam.

[0007] Preferably, the laser beam irradiation unit irradiates a laser beam of a wavelength that is absorbent by the workpiece. Preferably, the wavelength of the laser beam is in the range of 500 nm to 1000 nm.

[0008] Preferably, the conveying unit is a turntable that rotatably supports a holding table that holds a workpiece, and by the rotation of the turntable, the holding table that holds the workpiece is moved from the grinding unit to the energy supply unit. Effects of the invention

[0009] In this processing system, energy is supplied to the grinding surface of the workpiece to melt the grinding surface, including the damage caused by grinding. Therefore, the grinding surface can be flattened, and it is possible to repair at least a portion of the damage caused on the grinding surface. In addition, in the case of a laser beam, by making the wavelength absorbent for the workpiece, it is possible to melt not only the grinding surface but also the area near the grinding surface and repair the damage.

[0010] In addition, the energy supply unit melts the surface layer of the grinding surface by supplying energy, and then, as the cooled surface layer hardens again, at least a portion of the damage is repaired, thereby flattening the grinding surface. For this reason, unlike grinding or polishing which removes a portion of the surface layer of the workpiece, processing debris is not generated, and there is no risk of processing debris adhering to the workpiece or the processing chamber.

[0011] In addition, when a laser beam irradiation unit is used as an energy supply unit, processing by laser beam is a water-free process, so the treatment of waste liquid becomes unnecessary, allowing the equipment to be simplified.

[0012] In addition, in this processing system, the workpiece can be transported from the grinding unit to the energy supply unit by means of a transport unit. Therefore, within a single system, the workpiece can be ground by the grinding unit, and the damage to the workpiece caused by the grinding can be easily and quickly repaired by the energy supply unit. Consequently, it is possible to efficiently and effectively perform the grinding of the workpiece and the repair of damage. Brief explanation of the drawing

[0013] Figure 1 is a plan view illustrating the configuration of a grinding device, which is an example of a processing system. FIG. 2 is a perspective view illustrating the configuration of the first rough grinding unit and the first finishing grinding unit. FIG. 3 is a cross-sectional view illustrating the configuration of the first rough grinding unit and the first finishing grinding unit. FIG. 4 is a perspective view illustrating the configuration of the first laser beam irradiation unit. Figure 5 is a schematic diagram illustrating the configuration of the first laser beam irradiation unit. Figure 6 is a plan view illustrating an example of an energy supply stage. Figure 7 is a plan view illustrating a different processing system. FIG. 8 is a perspective view illustrating the configuration of the second laser beam irradiation unit. Figure 9 is a plan view illustrating another example of an energy supply stage. FIG. 10 is a perspective view illustrating an example of a return system. Figure 11 is a table showing the relationship between the wavelength of a laser beam emitted from a laser oscillator and the result of an energy supply step performed using each laser beam. Specific details for implementing the invention

[0014] The grinding device (1) illustrated in FIG. 1 is an example of a processing system and is equipped with a holding table (5) for holding a wafer (100), a first rough grinding unit (30), and a first finishing grinding unit (31). In the grinding device (1), the wafer (100) held on the holding table (5) is ground by the first rough grinding unit (30) and the first finishing grinding unit (31).

[0015] The wafer (100) illustrated in FIG. 1 is an example of a workpiece, such as a circular semiconductor wafer. A device not illustrated is formed on the surface (101) of the wafer (100). The surface (101) of the wafer (100) faces downward in FIG. 1 and is protected by having a protective tape (103) adhered to it. A grinding process is performed on the back surface (102) of the wafer (100).

[0016] The grinding device (1) is equipped with a device base (10) and a first controller (7) that controls each member of the grinding device (1).

[0017] A first cassette (150) and a second cassette (151) are arranged on the front side (-Y direction side) of the device base (10). The first cassette (150) and the second cassette (151) have a plurality of shelves inside, and one wafer (100) is accommodated in each shelf.

[0018] A robot hand (155) is positioned near the opening (not shown) of the first cassette (150) and the second cassette (151). The robot hand (155) brings the wafer (100) after processing into the first cassette (150) or the second cassette (151). Additionally, the robot hand (155) takes out the wafer (100) before processing from the first cassette (150) or the second cassette (151) and places it in a temporary placement unit (152).

[0019] A wafer (100) placed in a temporary placement unit (152) is placed on the holding surface (4) of a holding table (5) near the temporary placement unit (152) by an incoming unit (153).

[0020] The holding table (5) is provided with a holding surface (4) for holding a wafer (100). The holding surface (4) is connected to a suction source not shown, and can hold the wafer (100) by suction through a protective tape (103).

[0021] In addition, the holding table (5) can be rotated, for example, in the direction of the arrow (501), around a central axis extending in the Z-axis direction through the center of the holding surface (4) by means of the table rotation support mechanism (3) shown in FIG. 3 while holding the wafer (100) by the holding surface (4).

[0022] In this embodiment, as shown in FIG. 1, four holding tables (5) are arranged at equal intervals in the circumferential direction on the upper surface of a turntable (6) placed on a device base (10). The turntable (6) rotatably supports the holding tables (5) that support the wafer (100). The turntable (6) moves the holding tables (5) that support the wafer (100) between the first rough grinding unit (30), the first finishing grinding unit (31), and the first laser beam irradiation unit (40).

[0023] At the center of the turntable (6), an unillustrated rotation axis is disposed to rotate the turntable (6). The turntable (6) can rotate, for example, in the direction of the arrow (502), around an axis extending in the Z-axis direction by this rotation axis. As the turntable (6) rotates, four holding tables (5) revolve. By doing so, the turntable (6) can sequentially position the holding tables (5) that support the wafer (100) near the temporary placement unit (152), below the first rough grinding unit (30), below the first finishing grinding unit (31), and below the first laser beam irradiation unit (40).

[0024] In this way, the turntable (6) is an example of a conveying unit that conveys a wafer (100) from the first rough grinding unit (30) and the first finishing grinding unit (31) to the first laser beam irradiation unit (40). That is, in this embodiment, by rotating the turntable (6), the holding table (5) that supports the wafer (100) is moved from the first rough grinding unit (30) and the first finishing grinding unit (31) to the first laser beam irradiation unit (40).

[0025] A wafer (100) placed on the holding surface (4) of a holding table (5) by the receiving unit (153) is first positioned below the first rough grinding unit (30) shown in FIG. 1 by the rotation of the turntable (6). The first rough grinding unit (30) is an example of a grinding unit that grinds the wafer (100).

[0026] As shown in FIG. 2, the first rough grinding unit (30) is equipped with a grinding wheel (34) having a rough grinding stone (33) and a spindle (35) that rotatably supports the grinding wheel (34). As shown in FIG. 2, the first rough grinding unit (30) is configured to rough grind a wafer (100) held on a rotating holding table (5) by the rough grinding stone (33) of the grinding wheel (34) by rotating the grinding wheel (34) as indicated by arrow (503) and lowering the first rough grinding unit (30) as indicated by arrow (504).

[0027] Additionally, as illustrated in FIG. 3, the first rough grinding unit (30) is provided via a vertical moving unit (50) on a column (11) that is erected on a device base (10) (see FIG. 1). The vertical moving unit (50) holds the first rough grinding unit (30) and moves the first rough grinding unit (30) relative to a holding table (5) in a vertical direction (Z-axis direction).

[0028] The vertical movement unit (50) is equipped with a Z-axis guide rail (51) extending in the Z-axis direction and a retaining plate (52) that slides on the Z-axis guide rail (51). The retaining plate (52) holds the first rough grinding unit (30).

[0029] In the vertical movement unit (50), the retaining plate (52) moves along the Z-axis guide rail (51) in the Z-axis direction by the driving force of a motor not shown. As a result, the first rough grinding unit (30) held by the retaining plate (52) and the grinding wheel (34) provided on the first rough grinding unit (30) move together with the retaining plate (52) in the Z-axis direction.

[0030] After rough grinding by the first rough grinding unit (30), the wafer (100) is positioned below the first finishing grinding unit (31) shown in FIG. 1 by the rotation of the turntable (6). The first finishing grinding unit (31) is an example of a grinding unit that grinds the wafer (100) held on the holding table (5), and is provided, for example, on a column (11) installed upright on the device base (10). The first finishing grinding unit (31) has the same configuration as the first rough grinding unit (30), except that it has a finishing grinding stone (37) instead of a rough grinding stone (33), as shown in FIG. 2 and FIG. 3.

[0031] Additionally, the grinding device (1) is equipped with a vertical moving unit (50) for moving a first finishing grinding unit (31), having the same configuration as that for moving a first rough grinding unit (30) as shown in FIG. 3.

[0032] After finishing grinding by the first finishing grinding unit (31), the wafer (100) is positioned below the first laser beam irradiation unit (40) shown in FIG. 1 by the rotation of the turntable (6).

[0033] The first laser beam irradiation unit (40) is an example of an energy supply unit that supplies energy to the grinding surface of a wafer (100) ground by the first rough grinding unit (30) and the first finishing grinding unit (31) to melt it and repair at least a portion of the damage caused by grinding.

[0034] In addition, in this embodiment, the energy supply unit is described as a laser beam irradiation unit, but the energy supply unit is not limited to this and may be a plasma etching device that supplies plasma or a device that supplies electromagnetic waves or ion beams.

[0035] The first laser beam irradiation unit (40) irradiates a laser beam onto the grinding surface of a wafer (100) ground by the first rough grinding unit (30) and the first finishing grinding unit (31) to melt it and repair at least a portion of the damage caused by grinding. As shown in FIG. 4, the first laser beam irradiation unit (40) has a processing head (concentrator) (41) for irradiating a laser beam onto the wafer (100), a camera (42) for capturing an image of the grinding surface of the wafer (100), and a case (43) that supports them. Additionally, the configuration of the first laser beam irradiation unit (40) will be described later.

[0036] After irradiation with a laser beam, the wafer (100) is returned to the first cleaning unit (156) by the discharge unit (154) shown in FIG. 1 and cleaned. The cleaned wafer (100) is brought into the first cassette (150) or the second cassette (151) [the cassette from which the wafer (100) was discharged] by the robot hand (155).

[0037] The first controller (7) is equipped with a CPU that performs computational processing according to a control program, and a storage medium such as memory. The first controller (7) controls each component of the grinding device (1) to perform grinding processing on the wafer (100). Below, a method for processing the wafer (100) in the grinding device (1) by the control of the first controller (7) is described.

[0038] (1) Maintenance phase

[0039] In the processing of the wafer (100), first, the first controller (7) controls the robot hand (155) shown in FIG. 1 to take out the wafer (100) before processing from, for example, the first cassette (150) and place it in the temporary placement unit (152). In addition, the first controller (7) controls the receiving unit (153) to hold the wafer (100) on the temporary placement unit (152) and place it on the holding surface (4) of the holding table (5) with the back surface (102) as the top surface. After that, the first controller (7) connects the holding surface (4) to a suction source not shown. By doing so, the holding surface (4) sucks and holds the wafer (100) through the protective tape (103). In this way, the wafer (100) is held by the holding table (5).

[0040] (2) Grinding step

[0041] In this step, the first rough grinding unit (30) and the first finishing grinding unit (31) grind the wafer (100) held on the holding table (5).

[0042] (2-1) Rough Grinding Stage

[0043] After the holding step, the first controller (7) rotates the turntable (6) shown in FIG. 1 to position the holding table (5) holding the wafer (100) below the first rough grinding unit (30).

[0044] Then, the first controller (7) rotates the grinding wheel (34) of the first rough grinding unit (30) and grinds and moves the first rough grinding unit (30) along the Z-axis direction by means of the vertical movement unit (50) (see FIG. 3). In addition, the first controller (7) rotates the holding table (5) by means of the table rotation support mechanism (3).

[0045] Accordingly, the rough grinding stone (33) of the rotating grinding wheel (34) contacts the back surface (102) of the wafer (100) held on the rotating holding table (5), and rough grinds the back surface (102).

[0046] Additionally, the first controller (7) measures the thickness of the wafer (100) using a thickness measuring device not shown during grinding with the rough grinding wheel (33). Then, the first controller (7) performs grinding with the rough grinding wheel (33) until the thickness of the wafer (100) reaches a predetermined rough grinding thickness.

[0047] (2-2) Finishing grinding step

[0048] In the finishing grinding step, the grinding surface of the wafer (100) by the rough grinding wheel (33) is finished grinded. In this step, first, the first controller (7) rotates the turntable (6) shown in FIG. 1 to position the holding table (5) holding the wafer (100) below the first finishing grinding unit (31).

[0049] And, similar to the rough grinding stage, the first controller (7) rotates the grinding wheel (34) and, by means of the vertical movement unit (50), grinds and moves the first finishing grinding unit (31) along the Z-axis direction. In addition, the first controller (7) rotates the holding table (5) by means of the table rotation support mechanism (3).

[0050] Accordingly, the finishing grinding stone (37) of the rotating grinding wheel (34) contacts the back surface (102) of the wafer (100) held on the rotating holding table (5) and finish grinds the back surface (102).

[0051] Additionally, the first controller (7) measures the thickness of the wafer (100) using a thickness measuring device not shown during grinding with the finishing grinding wheel (37). Then, the first controller (7) performs grinding with the finishing grinding wheel (37) until the thickness of the wafer (100) reaches a predetermined finishing grinding thickness.

[0052] (3) Energy supply stage

[0053] In this step, the first laser beam irradiation unit (40) irradiates the back surface (102), which is the grinding surface of the wafer (100), with a laser beam to melt it, then cools it to recrystallize it, thereby repairing at least some of the damage caused by grinding. Additionally, the grinding surface is flattened as it is melted and solidified again. This damage (damage layer) is a processing altered part (processing altered layer) that includes, for example, cracks, scratches, and irregularities caused by grinding.

[0054] Here, the configuration of the first laser beam irradiation unit (40) is described. The first laser beam irradiation unit (40) includes at least a laser oscillator that emits a laser beam and a focusing lens that focuses the laser beam, and emits a laser beam of a wavelength that is absorbent to the wafer (100) which is the workpiece.

[0055] The first laser beam irradiation unit (40), in addition to the processing head (41) having a focusing lens, is equipped with a laser oscillator (75) that emits a laser beam, an X-axis direction disperser (76), and a resonant scanner (77), as shown in FIG. 5. These laser oscillator (75), X-axis direction disperser (76), and resonant scanner (77), etc., are installed in the case (43) and processing head (41) of the first laser beam irradiation unit (40) shown in FIG. 4.

[0056] The laser oscillator (75) emits a laser beam of a wavelength that is absorbent to the wafer (100). The X-axis direction disperser (76) has an optical deflection element (AOD) (762) and a first mirror (761) that guides the laser beam from the laser oscillator (75) to the optical deflection element (762), and adjusts the position of the laser beam emitted from the laser oscillator (75) in the X-axis direction. The laser beam from the X-axis direction disperser (76) is guided to a resonant scanner (77) through a second mirror (78).

[0057] The resonant scanner (77) is equipped with a movable oscillating mirror (771) that reflects incident light and moves the irradiation position (light path) of the laser beam back and forth along the Y-axis direction. By controlling the oscillating movement of the oscillating mirror (771), the resonant scanner (77) can move the irradiation position of the laser beam back and forth along the Y-axis direction at any frequency and deflection angle.

[0058] A laser beam from the resonant scanner (77) is guided to an fθ lens (79) in the processing head (41). The fθ lens (79) is a focusing lens that focuses the laser beam. The fθ lens (79) irradiates the laser beam from the resonant scanner (77) as a parallel laser beam (401) with the same focusing height onto the back surface (102), which is the grinding surface of the wafer (100) held on the holding surface (4) of the holding table (5).

[0059] The first controller (7) performs an energy supply step using the first laser beam irradiation unit (40) having such a configuration.

[0060] That is, the first controller (7) first rotates the turntable (6) shown in FIG. 1 to place the holding table (5) holding the wafer (100) below the first laser beam irradiation unit (40).

[0061] Next, the first controller (7) emits a laser beam from the laser oscillator (75) in the first laser beam irradiation unit (40) shown in FIG. 5 and controls the oscillation state of the oscillation mirror (771) in the resonant scanner (77) to irradiate the laser beam (401) output from the fθ lens (79) to a long first range (402) from the center of the back surface (102) of the wafer (100) to the outer edge, as shown in FIG. 6.

[0062] Then, the first controller (7) rotates the holding table (5) as indicated by the arrow (501). By doing so, a laser beam (401) is irradiated from the fθ lens (79) of the first laser beam irradiation unit (40) onto the entire back surface (102), which is the grinding surface of the wafer (100), and the entire back surface (102) is melted. In addition, in this embodiment, since a laser beam (401) of a wavelength that is absorbent to the wafer (100) is used, not only the back surface (102) but also a portion (part near the back surface) up to a predetermined thickness from the back surface (102) is melted. The portion near the back surface to be melted varies depending on the condition of the damage, but for example, it is a portion with a thickness of about 0.5 μm to 1.5 μm or 0.5 μm to 4 μm from the back surface (102).

[0063] After that, the first controller (7) stops the irradiation of the laser beam (401). As a result, the molten back surface (102) and the area near the back surface cool and solidify.

[0064] (4) Cleaning step

[0065] After the energy supply step, the first controller (7) returns the wafer (100) to the first cleaning unit (156) by means of the outgoing unit (154) shown in FIG. 1 and cleans the wafer (100). The first controller (7) brings the cleaned wafer (100) into the first cassette (150) or the second cassette (151) by means of the robot hand (155).

[0066] As described above, in this embodiment, after the grinding step, an energy supply step is performed to irradiate a laser beam onto the back surface (102), which is the grinding surface of the wafer (100) ground by the first rough grinding unit (30) and the first finishing grinding unit (31), thereby melting the back surface (102) and the area near the back surface, including the damage caused by the grinding. Additionally, thereafter, the back surface (102) and the area near the back surface are cooled and hardened.

[0067] In this embodiment, through the process of melting and cooling the back surface (102) of the wafer (100), crystal growth can be performed on the molten region of the back surface (102) and the area near the back surface to form a seed crystal, and then recrystallization can be performed. Accordingly, the back surface (102) can be flattened, and cracks and defects caused by grinding on the back surface (102) and the area near the back surface can be combined, making it possible to repair at least some of the damage to the surface (101) and the area near the back surface. In addition, since the cutting strength of the wafer (100) can be increased by flattening, the risk of cracks or defects occurring in the wafer (100) during the process after the energy supply step can be reduced, and the cutting strength of the chip can be increased when chipping occurs.

[0068] Here, for the treatment of the grinding surface (flattening and repair of damage), it is also considered to grind the grinding surface using a grinding pad (CMP grinding or dry grinding). However, CMP is a treatment using a chemical solution, and a configuration for treating the liquid chemical solution is required. Furthermore, in CMP grinding and dry grinding, since a portion of the grinding surface is removed, grinding debris is generated, and there is a risk that the grinding debris may adhere to the workpiece or contaminate the inside of the device. In contrast, in the treatment in which the wafer (100) is melted by the first laser beam irradiation unit (40) to remove damage, liquid treatment is unnecessary and processing debris is not generated, so the equipment can be simplified and contamination of the workpiece and the device can be suppressed.

[0069] In addition, in this embodiment, the grinding device (1) is equipped with a first rough grinding unit (30), a first finishing grinding unit (31), and a first laser beam irradiation unit (40) on a single device base (10), and a wafer (100) is conveyed from the first rough grinding unit (30) and the first finishing grinding unit (31) to the first laser beam irradiation unit (40) by a turntable (6). Because of this, within a single grinding device (1), the wafer (100) can be ground by the first rough grinding unit (30) and the first finishing grinding unit (31), and the damage to the wafer (100) caused by the grinding can be easily and quickly repaired by the first laser beam irradiation unit (40). Therefore, it is possible to efficiently and effectively perform the grinding of the wafer (100) and the repair of damage.

[0070] In addition, in this embodiment, the material of the wafer (100) as the workpiece is preferably a liquid-phase growing material such as Si, Ge, and GaAs. Liquid-phase growing materials are prone to melting when energy is supplied by irradiation of a laser beam, etc. Therefore, damage formed on the grinding surface of the wafer (100) can be effectively repaired by supplying energy such as irradiation of a laser beam.

[0071] In addition, in the above-described embodiment, the first laser beam irradiation unit (40) has a configuration using a resonant scanner (77) to reciprocate the irradiation position of the laser beam along the Y-axis direction. Alternatively, the first laser beam irradiation unit (40) may use a galvanometer scanner to reciprocate the irradiation position of the laser beam along the Y-axis direction.

[0072] In addition, in the above-described embodiment, a grinding device (1) was described in which a first rough grinding unit (30), a first finishing grinding unit (31), and a first laser beam irradiation unit (40) are provided on a single device base (10). However, this is not limited to this, and the first rough grinding unit (30), the first finishing grinding unit (31), and the first laser beam irradiation unit (40) may be configured as separate devices. In this case, a processing system (2) as shown in FIG. 7 may be adopted.

[0073] As illustrated in FIG. 7, the processing system (2) has a second rough grinding unit (38) for rough grinding the wafer (100), a second finishing grinding unit (39) for finishing grinding the wafer (100), a second laser beam irradiation unit (45) for irradiating the wafer (100) with a laser beam, a second cleaning unit (157) for cleaning the wafer (100), a cassette placement unit (160), and a first transport unit (90) and a second transport unit (95) for transporting the wafer (100). Additionally, the processing system (2) is equipped with a second controller (8) for controlling each component of the processing system (2).

[0074] The second rough grinding unit (38) and the second finishing grinding unit (39) are equipped with a holding mechanism (such as a holding table) for holding the wafer (100), and have the same function as the first rough grinding unit (30) and the first finishing grinding unit (31) described above, and are configured to rough grind and finish grind the back surface (102) of the wafer (100), respectively.

[0075] In addition, the second laser beam irradiation unit (45) is also equipped with a holding mechanism for holding the wafer (100) and has the same function as the first laser beam irradiation unit (40) described above, and irradiates a laser beam onto the grinding surface of the wafer (100) to melt it and repair at least a portion of the damage caused by grinding. This second laser beam irradiation unit (45) is also an example of an energy supply unit, just like the first laser beam irradiation unit (40).

[0076] In addition, the second cleaning unit (157) also cleans the wafer (100) in the same way as the first cleaning unit (156). In addition, the cassette placement unit (160) has third to sixth cassettes (161 to 164) that accommodate the wafer (100).

[0077] The first transport unit (90) is equipped with a first guide rail (91) that extends approximately parallel to the direction in which the third to sixth cassettes (161 to 164) are arranged, and a first robot (92) that can move along the first guide rail (91). In the first transport unit (90), the first robot (92) can perform the extraction and storage of wafers (100) for the third to sixth cassettes (161 to 164). In the first transport unit (90), the first robot (92) places the wafer (100) extracted from any one of the third to sixth cassettes (161 to 164) into, for example, a position alignment unit not illustrated.

[0078] The second conveying unit (95) is equipped with a second guide rail (96) and a second robot (97) movable along the second guide rail (96). The second guide rail (96) extends approximately parallel to the direction in which the second rough grinding unit (38), the second cleaning unit (157), and the second laser beam irradiation unit (45) are arranged, and is positioned between them and the second finishing grinding unit (39).

[0079] In the second conveying unit (95), the wafer (100) placed in the positioning unit (not shown) by the first robot (92) of the first conveying unit (90) can be held by the second robot (97). Additionally, in the second conveying unit (95), the wafer (100) can be conveyed by the second robot (97) between the second rough grinding unit (38), the second finishing grinding unit (39), the second laser beam irradiation unit (45), and the second cleaning unit (157). That is, the second conveying unit (95) can convey the wafer (100) from the second rough grinding unit (38) and the second finishing grinding unit (39) to the second laser beam irradiation unit (45).

[0080] In a processing system (2) having such a configuration, a second controller (8) controlling the processing system (2) extracts a wafer (100) from any one of the third to sixth cassettes (161 to 164) by means of a first transport unit (90), and holds the wafer (100) on the second robot (97) of the second transport unit (95) through a position alignment unit not shown. Then, the second controller (8) performs the aforementioned grinding step, energy supply step, and cleaning step on the wafer (100) while moving the wafer (100) between the second rough grinding unit (38), the second finishing grinding unit (39), the second laser beam irradiation unit (45), and the second cleaning unit (157) by means of the second transport unit (95).

[0081] In this processing system (2), just like in the grinding device (1), the back surface (102) of the wafer (100) can be flattened by a process of melting and cooling by the second laser beam irradiation unit (45) on the back surface (102), which is the grinding surface, and at least some of the damage to the back surface (102) and the area near the back surface can be repaired.

[0082] Additionally, in the processing system (2), the wafer (100) can be transported from the second rough grinding unit (38) and the second finishing grinding unit (39) to the second laser beam irradiation unit (45) by the second transport unit (95). Because of this, within a single processing system (2), the wafer (100) can be ground by the second rough grinding unit (38) and the second finishing grinding unit (39), and the damage to the wafer (100) caused by the grinding can be easily and quickly repaired by the second laser beam irradiation unit (45). Therefore, it is possible to efficiently and effectively perform the grinding of the wafer (100) and the repair of damage.

[0083] Additionally, in the processing system (2), it is possible to use a configuration as shown in FIG. 8 as a second laser beam irradiation unit (45). When using the second laser beam irradiation unit (45) shown in FIG. 8, the wafer (100) in the processing system (2) is treated as a work set (110) including, for example, a ring frame (111), an adhesive tape (113), and the wafer (100).

[0084] The second laser beam irradiation unit (45) illustrated in FIG. 8 has a base (115), and on the upper surface of the base (115) has a holding table (143), a holding table section (140), an X-axis moving mechanism (120) for moving the holding table (143) in the X-axis direction, and a Y-axis moving mechanism (130) for moving the holding table (143) in the Y-axis direction.

[0085] The X-axis moving mechanism (120) moves the holding table (143) in the X-axis direction relative to the processing head (41). The X-axis moving mechanism (120) includes a pair of guide rails (123) extending in the X-axis direction, an X-axis table (124) placed on the guide rails (123), a ball screw (125) extending parallel to the guide rails (123), and a drive motor (126) that rotates the ball screw (125).

[0086] A pair of guide rails (123) are arranged on the upper surface of the base (115) parallel to the X-axis direction. An X-axis table (124) is installed on the pair of guide rails (123) so as to be slidable along these guide rails (123). A Y-axis movement mechanism (130) and a holding table section (140) are arranged on the X-axis table (124).

[0087] The ball screw (125) is screw-coupled to a nut portion (not shown) formed on the X-axis table (124). A drive motor (126) is connected to one end of the ball screw (125) and drives the ball screw (125) to rotate. As the ball screw (125) is driven to rotate, the X-axis table (124), the Y-axis moving mechanism (130), and the holding table portion (140) move along the guide rail (123) in the X-axis direction.

[0088] The Y-axis movement mechanism (130) moves the holding table (143) in the X-axis direction relative to the processing head (41). The Y-axis movement mechanism (130) comprises a pair of guide rails (131) extending in the Y-axis direction, a Y-axis table (132) placed on the guide rails (131), a ball screw (133) extending parallel to the guide rails (131), and a drive motor (135) that rotates the ball screw (133).

[0089] A pair of guide rails (131) are arranged on the upper surface of the X-axis table (124) parallel to the Y-axis direction. A Y-axis table (132) is installed on the pair of guide rails (131) so as to be slidable along these guide rails (131). A retaining table section (140) is arranged on the Y-axis table (132).

[0090] The ball screw (133) is screw-coupled to a nut portion (not shown) formed on the Y-axis table (132). A drive motor (135) is connected to one end of the ball screw (133) and drives the ball screw (133) to rotate. As the ball screw (133) is driven to rotate, the Y-axis table (132) and the holding table portion (140) move along the guide rail (131) in the Y-axis direction.

[0091] The holding table section (140) has a holding table (143) for holding a wafer (100), a clamp section (145) installed around the holding table (143), a support post (147) for supporting the holding table (143), and a cover plate (146) installed on the top of the support post (147) to surround the holding table (143).

[0092] On the upper surface of the holding table (143), a holding surface (144) containing a porous material is formed. This holding surface (144) is connected to a suction source (not shown) so that it is possible to suction and hold a wafer (100) from a work set (110).

[0093] Four clamp parts (145) are installed around the holding table (143). The four clamp parts (145) clamp and fix the ring frame (111) around the wafer (100) held on the holding table (143) from all sides.

[0094] Additionally, the second laser beam irradiation unit (45) is provided on the base (115) and has a housing (116) having a processing head (41) and a camera (42).

[0095] The housing (116) contains, for example, a laser oscillator (75) shown in FIG. 5, an X-axis direction disperser (76), a second mirror (78), and a resonant scanner (77). Additionally, the processing head (41) has an fθ lens (79) shown in FIG. 5. Accordingly, the second laser beam irradiation unit (45) can emit a laser beam of an absorbent wavelength onto a wafer (100) held on the holding table (143) of the holding table section (140), just like the first laser beam irradiation unit (40).

[0096] In a processing system (2) equipped with a second laser beam irradiation unit (45) having such a configuration, the second controller (8) emits a laser beam from the laser oscillator (75) shown in FIG. 5 and irradiates a laser beam (401) onto the back surface (102) of a wafer (100) held on a holding table (143) from the fθ lens (79) of the processing head (41).

[0097] At this time, the second controller (8) irradiates the laser beam (401) to the -X side end of the back surface (102) of the wafer (100) by controlling the X-axis movement mechanism (120) as shown in FIG. 9. At this time, the second controller (8) sets the irradiation range of the laser beam (401) to a first range (405) that is longer than the length of the wafer (100) in the Y-axis direction by controlling the oscillation state of the oscillation mirror (771) in the resonant scanner (77).

[0098] Additionally, the second controller (8) controls the X-axis movement mechanism (120) (see FIG. 8) to move the holding table (143) holding the wafer (100) along the -X direction. As a result, as indicated by the arrow (510) in FIG. 9, the first range (405) moves in the relative +X direction on the back surface (102) of the wafer (100). At this time, the length of the first range (405), which is the irradiation range of the laser beam (401), is appropriately set so that it is longer than the length of the wafer (100) in the Y-axis direction at the part where the first range (405) is located.

[0099] In this way, a laser beam (401) is irradiated from the fθ lens (79) of the second laser beam irradiation unit (45) onto the entire back surface (102), which is the grinding surface of the wafer (100), and the entire back surface (102) is melted. As a result, the back surface (102) is flattened, and at least some of the damage to the back surface (102) and the area near the back surface is repaired.

[0100] Additionally, the length of the first range (405) may be set longer than the diameter of the wafer (100), regardless of the position of the first range (405) in the wafer (100).

[0101] Additionally, the processing system (2) illustrated in FIG. 7 may have a conveying system (200) as illustrated in FIG. 10 instead of the first conveying unit (90) and the second conveying unit (95).

[0102] The conveying system (200) is an example of a conveying unit and is equipped with a traveling rail (205). The traveling rail (205) is installed across the units such as the second rough grinding unit (38), the second finishing grinding unit (39), the second laser beam irradiation unit (45), the second cleaning unit (157), and the cassette placement unit (160) shown in FIG. 7 so as to convey the wafer (100). That is, the units are connected to each other through the traveling rail (205). In addition, the traveling rail (205) is positioned above the case (250) of the units, as shown in FIG. 10.

[0103] Additionally, the conveying system (200) is equipped with a tray (210) that accommodates a work set (110) including a wafer (100), and an automatic conveyor (215) that conveys the tray (210). The automatic conveyor (215) can convey the work set (110) including the wafer (100) between each unit by traveling on a travel rail (205) while maintaining the tray (210) that accommodates the work set (110). That is, the conveying system (200) conveys the wafer (100) from the second rough grinding unit (38) and the second finishing grinding unit (39) to the second laser beam irradiation unit (45) by means of the automatic conveyor (215).

[0104] An opening (255) is formed at the corner of the upper plate (251) of the case (250) of each unit. Additionally, a tray support (260) for supporting a tray (210) is installed in the case (250). The tray support (260) is raised by a lifting mechanism (not shown) to pass through the opening (255) while supporting the tray (210).

[0105] Additionally, the conveying system (200) has a tray conveying arm (220) near the opening (255). The tray conveying arm (220) conveys the tray (210) between a tray support (260) located at a height equal to the opening (255) and an automatic conveyor (215) stopped near the opening (255).

[0106] Accordingly, it is possible to bring a work set (110) containing a wafer (100) into a case (250) by stopping an automatic transport vehicle (215) holding a tray (210) containing a work set (110) near a case (250) of each unit, transferring the tray (210) to a tray support (260) of the case (250) by means of a tray transport arm (220), and lowering the tray support (260) by means of a lifting mechanism not shown.

[0107] Additionally, it is possible to transfer the work set (110) to another unit by receiving the work set (110), which includes the wafer (100) after processing within the case (250) of each unit, into a tray (210), supporting the tray (210) by a tray support (260), raising it to an opening (255) by a lifting mechanism, and transferring it to an automatic transport vehicle (215) by a tray transport arm (220).

[0108] When using such a return system (200), the second controller (8) performs the aforementioned grinding step, energy supply step, and cleaning step on the wafer (100) while moving the wafer (100) between the second rough grinding unit (38), the second finishing grinding unit (39), the second laser beam irradiation unit (45), the second cleaning unit (157), and the cassette placement unit (160) by means of the return system (200).

[0109] Accordingly, in this case as well, the back surface (102), which is the grinding surface of the wafer (100), is flattened by laser irradiation by the second laser beam irradiation unit (45), and at least some of the damage to the back surface (102) and the area near the back surface is repaired.

[0110] Additionally, the wafer (100) can be transported from the second rough grinding unit (38) and the second finishing grinding unit (39) to the second laser beam irradiation unit (45) by the transport system (200). Because of this, within a single processing system (2), the wafer (100) can be ground by the second rough grinding unit (38) and the second finishing grinding unit (39), and the damage to the wafer (100) caused by the grinding can be easily and quickly repaired by the second laser beam irradiation unit (45). Therefore, it is possible to efficiently and effectively perform the grinding of the wafer (100) and the repair of damage.

[0111] In addition, as described above, the laser oscillator (75) of the first laser beam irradiation unit (40) illustrated in FIG. 5 emits a laser beam of a wavelength that is absorbent to the wafer (100). For example, when the wafer (100) is a silicon wafer, the wavelength of the laser beam emitted from the laser oscillator (75) is a wavelength in the range of 500 nm to 1000 nm, which is absorbent to silicon.

[0112] FIG. 11 is a diagram showing a table illustrating the relationship between the wavelength of a laser beam emitted from a laser oscillator (75) and the result (processing result) of an energy supply step performed using each laser beam. As shown in this table, when the wavelength is in the range of 500 nm to 1000 nm, it was possible to effectively melt the back surface (102) and the area near the back surface, which is the grinding surface of the silicon wafer (100).

[0113] Meanwhile, when the wavelength is 355 nm or less, it was difficult to sufficiently melt the back surface (102) and the area near the back surface, which is the grinding surface of the silicon wafer (100). Also, when the wavelength is 1064 nm, it was difficult to properly melt the back surface (102) and the area near the back surface because the laser beam passes through the wafer (100).

[0114] In addition, during the energy supply stage, energy may be supplied in any form. For example, instead of irradiating with a laser beam, plasma, an ion beam, electromagnetic waves, etc., may be supplied to the grinding surface of the workpiece to melt it, thereby repairing at least a portion of the damage caused by grinding. If the energy supply unit is a plasma supply device that supplies plasma to the workpiece, for example, a plasma supply device is used that includes a vacuum chamber, a holding table that holds a wafer (100) (workpiece) within the vacuum chamber, and a plasma supply unit that supplies a plasma-type gas to the wafer (100) held on the holding table. Explanation of the symbols

[0115] 1: Grinding device 2: Machining system 3: Table rotation support mechanism 4: Retaining surface 5: Hold table 6: Turntable 7: 1st Controller 8: 2nd Controller 10: Device base 11: Column 30: 1st rough grinding unit 31: 1st finishing grinding unit 33: Rough grinding wheel 34: Grinding wheel 35: Spindle 37: Finishing grinding wheel 38: 2nd rough grinding unit 39: 2nd finishing grinding unit 40: 1st laser beam irradiation unit 41: Processing head 42: Camera 43: Case 45: 2nd Laser Beam Irradiation Unit 50: Vertical Movement Unit 51: Z-axis guide rail 52: Retaining plate 75: Laser oscillator 76: X-axis disperser 77: Resonant Scanner 78: Second Mirror 79: fθ lens 90: First return unit 91: 1st guide rail 92: 1st robot 95: 2nd return unit 96: 2nd guide rail 97: Robot No. 2 100: Wafer 101: Surface 102: Back side 103: Protective tape 110: Work set 111: Ring frame 113: Adhesive tape 115: Base 116: Housing 120: X-axis movement mechanism 123: Guide rail 124: X-axis table 125: Ball screw 126: Drive motor 130: Y-axis movement mechanism 131: Guide rail 132: Y-axis table 133: Ball screw 135: Drive motor 140: Maintenance Table Section 143: Maintenance Table 144: Retaining surface 145: Clamp part 146: Cover plate 147: Support 150: 1st Cassette 151: 2nd Cassette 152: Temporary Deployment Unit 153: Import Unit 154: Export Unit 155: Robot Hand 156: 1st Cleaning Unit 157: 2nd Cleaning Unit 160: Cassette Placement Unit 161: Third Cassette 162: 4th Cassette 163: 5th Cassette 164: Cassette 6 200: Return System 205: Running rail 210: Tray 215: Automatic return vehicle 220: Tray return arm 250: Case 251: Top plate 255: Opening 260: Tray support 401: Laser beam 402: First range 405: 1st Range 761: 1st Mirror 762: Optical deflection element 771: Oscillating mirror

Claims

Claim 1 A workpiece processing system comprising: a grinding unit for grinding a workpiece, the grinding unit comprising a grinding wheel and a spindle that rotatably supports the grinding wheel; an energy supply unit for supplying energy to the grinding surface of the workpiece ground by the grinding unit to melt and repair at least a portion of the damage caused by grinding; and a conveying unit for conveying the workpiece from the grinding unit to the energy supply unit, wherein the energy supply unit comprises a laser oscillator for emitting a laser beam and a focusing lens for focusing the laser beam, and a laser beam irradiation unit for irradiating the laser beam, wherein the laser beam irradiation unit is configured to irradiate a laser beam with a long, narrow irradiation range from the center of the grinding surface of the circular workpiece to the outer edge of the grinding surface of the workpiece rotating. Claim 2 A processing system according to claim 1, wherein the energy supply unit comprises a resonant scanner having a oscillating mirror that reflects incident light, and the resonant scanner is configured to reciprocate the irradiation position of a laser beam along a specific direction by controlling the oscillating movement of the oscillating mirror. Claim 3 In claim 1, the laser beam irradiation unit is a processing system that irradiates a laser beam of a wavelength having absorption properties with respect to the workpiece. Claim 4 A processing system according to claim 1, wherein the wavelength of the laser beam is in the range of 500 nm to 1000 nm. Claim 5 A processing system according to claim 1, wherein the material of the workpiece is a liquid-phase growing material. Claim 6 A processing system according to claim 1, wherein the conveying unit is a turntable that rotatably supports a holding table that holds a workpiece, and moves the holding table that holds the workpiece from the grinding unit to the energy supply unit by the rotation of the turntable.

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