Processing system

Abstract

To flatten a grinding surface after grinding and remove at least a portion of damage due to grinding.SOLUTION: A laser beam is applied to a rear surface 102 being a grinding surface of a ground wafer 100, and the rear surface 102 and a portion near the rear surface are melted. Therefore, the rear surface 102 can be flattened and at least a portion of damage on a front surface 101 and the portion near the rear surface can be repaired. A grinding device 1 conveys the wafer 100 to a first laser beam irradiation unit 40 from a first rough grinding unit 30 and a first finishing grinding unit 31 by a turntable 6. Therefore, in one grinding device 1, the wafer 100 is ground and damage on the wafer 100 generated by grinding can be easily and quickly repaired. Consequently, grinding of the wafer 100 and repairing of damage can be efficiently and excellently executed.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] As disclosed in Patent Document 1, after grinding a workpiece, in order to flatten the surface irregularities and remove grinding marks and damage caused by grinding, polishing with a polishing pad is generally performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a new processing system capable of flattening a grinding surface after grinding and removing at least a part of the damage caused by grinding.

Means for Solving the Problems

[0005] A processing system for a workpiece according to the present invention (this processing system) includes a grinding wheel and a spindle that rotatably supports the grinding wheel, a grinding unit for grinding the workpiece, and an energy supply unit that supplies energy to the grinding surface of the workpiece ground by the grinding unit to melt it and repair at least a part of the damage generated by grinding, and a transfer unit that transfers the workpiece from the grinding unit to the energy supply unit. The energy supply unit includes at least an oscillator that oscillates a laser beam and a condenser lens that condenses the laser beam, and is a laser beam irradiation unit that irradiates a laser beam. The laser beam irradiation unit irradiates From the center to the outer edge of the grinding surface of a circular workpiece a laser beam with an elongated irradiation range rotateIt is configured to irradiate the grinding surface of the workpiece. Alternatively, the processing system comprises a grinding unit for grinding a workpiece, which includes a grinding wheel and a spindle that rotatably supports the grinding wheel; an energy supply unit for supplying energy to the ground surface of the workpiece ground by the grinding unit to melt it and repair at least a portion of the damage caused by grinding; and a transport unit for transporting the workpiece from the grinding unit to the energy supply unit, wherein the energy supply unit is a laser beam irradiation unit for irradiating a laser beam, which includes at least an oscillator for emitting a laser beam and a focusing lens for focusing the laser beam, and the laser beam irradiation unit is configured to irradiate the ground surface of a workpiece moving in a second direction perpendicular to the first direction with a laser beam having an elongated irradiation range extending in a first direction, and the length of the irradiation range of the laser beam in the first direction is longer than the length of the portion of the workpiece in the first direction where the irradiation range is located. In this processing system, the laser beam irradiation unit may be equipped with a resonant scanner or a galvanometer scanner for forming the irradiation area of ​​the laser beam. In this processing system, the laser beam irradiation unit may irradiate the workpiece with a laser beam of a wavelength that is absorbed by it. In this processing system, the wavelength of the laser beam may be in the range of 500 to 1000 nm. In this processing system, the material of the workpiece may be a material grown using liquid phase growth. In this processing system, the transport unit may be a turntable that rotatably supports a holding table that holds a workpiece, and the holding table that holds the workpiece may be moved from the grinding unit to the energy supply unit by the rotation of the turntable. [Effects of the Invention]

[0006] This processing system supplies energy to the grinding surface of the workpiece, melting the surface, including the damage caused by grinding. Therefore, it is possible to flatten the grinding surface and repair at least some of the damage. Furthermore, in the case of a laser beam, by using a wavelength that is absorbed by the workpiece, it is possible to melt not only the grinding surface but also the surrounding area, repairing the damage there as well. Furthermore, the energy supply unit melts the surface layer of the grinding surface by supplying energy, and then the cooled surface layer solidifies again, repairing at least part of the damage and flattening the grinding surface. As a result, unlike grinding or polishing which remove a portion of the surface layer of the workpiece, no processing chips are generated, and there is no risk of processing chips adhering to the workpiece or the processing chamber. Furthermore, when a laser beam irradiation unit is used as the energy supply unit, laser beam processing does not use water, eliminating the need for waste liquid treatment and simplifying the equipment.

[0007] Furthermore, in this processing system, the workpiece can be transported from the grinding unit to the energy supply unit by 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 grinding can be easily and quickly repaired by the energy supply unit. Thus, it is possible to efficiently and effectively perform grinding and damage repair of the workpiece. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram showing the configuration of a grinding machine, which is an example of a processing system. [Figure 2] This is a perspective view showing the configuration of the first rough grinding unit and the first finish grinding unit. [Figure 3] This is a cross-sectional view showing the configuration of the first rough grinding unit and the first finish grinding unit. [Figure 4] This is a perspective view showing the configuration of the first laser beam irradiation unit. [Figure 5] This is an explanatory diagram showing the configuration of the first laser beam irradiation unit. [Figure 6] This is an explanatory diagram illustrating an example of an energy supply step. [Figure 7] This is an explanatory diagram showing other processing systems. [Figure 8] This is an explanatory diagram showing the configuration of the second laser beam irradiation unit. [Figure 9] This is an explanatory diagram showing another example of the energy supply step. [Figure 10] This is an explanatory diagram showing an example of a transport system. [Figure 11]A diagram showing a table indicating the relationship between the wavelength of the laser beam oscillated from the oscillator and the result of the energy supply step performed using each laser beam.

Embodiment for Carrying Out the Invention

[0009] The grinding apparatus 1 shown in FIG. 1 is an example of a processing system, and includes a holding table 5 for holding a wafer 100, a first rough grinding unit 30, and a first finish grinding unit 31. In the grinding apparatus 1, the wafer 100 held by the holding table 5 is ground by the first rough grinding unit 30 and the first finish grinding unit 31.

[0010] The wafer 100 shown in FIG. 1 is an example of a workpiece, and is, for example, a circular semiconductor wafer. Devices (not shown) are 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 attaching a protective tape 103. A grinding process is performed on the back surface 102 of the wafer 100.

[0011] The grinding apparatus 1 includes a device base 10 and a first control unit 7 that controls each member of the grinding apparatus 1.

[0012] On the front side (-Y direction side) of the device base 10, a first cassette 150 and a second cassette 15 is are arranged. The first cassette 150 and the second cassette 151 each have a plurality of shelves inside, and one wafer 100 is accommodated on each shelf.

[0013] Near the openings (not shown) of the first cassette 150 and the second cassette 151, a robot hand 155 is disposed. The robot hand 155 carries the processed wafer 100 into the first cassette 150 or the second cassette 151. Further, the robot hand 155 takes out the wafer 100 before processing from the first cassette 150 or the second cassette 151 and places it on the temporary placement unit 152.

[0014] The wafer 100 placed on the temporary placement unit 152 is placed on the holding surface 4 of the holding table 5 near the temporary placement unit 152 by the loading unit 153.

[0015] The holding table 5 has a holding surface 4 for holding the wafer 100. The holding surface 4 is communicated with a suction source (not shown) and can suck and hold the wafer 100 through the protective tape 103.

[0016] Also, while the holding table 5 holds the wafer 100 by the holding surface 4, it can rotate, for example, in the direction of arrow 501 around a central axis that passes through the center of the holding surface 4 and extends in the Z-axis direction by the table rotation support mechanism 3 shown in FIG. 3.

[0017] In the present embodiment, as shown in FIG. 1, four holding tables 5 are arranged at equal intervals in the circumferential direction on the upper surface of the turntable 6 arranged on the apparatus base 10. The turntable 6 rotatably supports the holding table 5 that supports the wafer 100. And the turntable 6 moves the holding table 5 that supports the wafer 100 among the first rough grinding unit 30, the first finish grinding unit 31, and the first laser beam irradiation unit 40.

[0018] At the center of the turntable 6, a rotation axis (not shown) for rotating the turntable 6 is arranged. The turntable 6 can rotate, for example, in the direction of arrow 502 around an axis extending in the Z-axis direction by this rotation axis. When the turntable 6 rotates, the four holding tables 5 revolve. Thereby, the turntable 6 can sequentially position the holding table 5 that supports the wafer 100 near the temporary placement unit 152, below the first rough grinding unit 30, below the first finish grinding unit 31, and below the first laser beam irradiation unit 40.

[0019] Thus, the turntable 6 is an example of a transport unit that transports the wafer 100 from the first rough grinding unit 30 and the first finish grinding unit 31 to the first laser beam irradiation unit 40. In other words, in this embodiment, the rotation of the turntable 6 moves the holding table 5 that supports the wafer 100 from the first rough grinding unit 30 and the first finish grinding unit 31 to the first laser beam irradiation unit 40.

[0020] The wafer 100, placed on the holding surface 4 of the holding table 5 by the loading unit 153, is first positioned below the first rough grinding unit 30 shown in Figure 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.

[0021] As shown in Figure 2, the first rough grinding unit 30 comprises a grinding wheel 34 having a rough grinding wheel 33, and a spindle 35 that rotatably supports the grinding wheel 34. As shown in Figure 2, the first rough grinding unit 30 is configured to roughly grind the wafer 100 held on the rotating holding table 5 by the rough grinding wheel 33 of the grinding wheel 34, by lowering the first rough grinding unit 30 as indicated by arrow 504 while rotating the grinding wheel 34 as indicated by arrow 503.

[0022] Furthermore, as shown in Figure 3, the first rough grinding unit 30 is mounted on a column 11 erected on the device base 10 (see Figure 1) via a vertical movement unit 50. The vertical movement unit 50 holds the first rough grinding unit 30 and moves the first rough grinding unit 30 relative to the holding table 5 in the vertical direction (Z-axis direction).

[0023] The vertical movement unit 50 includes a Z-axis guide rail 51 extending in the Z-axis direction and a holding plate 52 that slides along the Z-axis guide rail 51. The holding plate 52 holds the first rough grinding unit 30.

[0024] In the vertical movement unit 50, the holding plate 52 moves in the Z-axis direction along the Z-axis guide rail 51 due to the driving force of a motor (not shown). As a result, the first rough grinding unit 30, which is held by the holding plate 52, and the grinding wheel 34 provided on the first rough grinding unit 30, move together with the holding plate 52 in the Z-axis direction.

[0025] After rough grinding by the first rough grinding unit 30, the wafer 100 is positioned below the first finish grinding unit 31 shown in Figure 1 by the rotation of the turntable 6. The first finish grinding unit 31 is an example of a grinding unit that grinds a wafer 100 held on a holding table 5, and is provided, for example, on a column 11 erected on a device base 10. The first finish grinding unit 31 has the same configuration as the first rough grinding unit 30, except that it has a finish grinding wheel 37 instead of a rough grinding wheel 33, as shown in Figures 2 and 3.

[0026] Furthermore, as shown in Figure 3, the grinding apparatus 1 includes a vertical movement unit 50 for moving the first finish grinding unit 31, which has a configuration similar to that for moving the first rough grinding unit 30.

[0027] After finish grinding by the first finish grinding unit 31, the wafer 100 is positioned below the first laser beam irradiation unit 40 shown in Figure 1 by the rotation of the turntable 6.

[0028] The first laser beam irradiation unit 40 is an example of an energy supply unit that supplies energy to the ground surface of the wafer 100 ground by the first rough grinding unit 30 and the first finish grinding unit 31, causing it to melt and repair at least some of the damage caused by grinding. 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.

[0029] The first laser beam irradiation unit 40 irradiates the ground surface of the wafer 100, which has been ground by the first rough grinding unit 30 and the first finish grinding unit 31, with a laser beam to melt it and repair at least a portion of the damage caused by grinding. As shown in Figure 4, the first laser beam irradiation unit 40 has a processing head (concentrator) 41 for irradiating the wafer 100 with a laser beam, a camera 42 for imaging the ground surface of the wafer 100, and a housing 43 that supports them. The configuration of the first laser beam irradiation unit 40 will be described later.

[0030] After irradiation with a laser beam, the wafer 100 is transported to the first cleaning unit 156 by the transport unit 154 shown in Figure 1 and cleaned. The cleaned wafer 100 is then loaded by the robot hand 155 into either the first cassette 150 or the second cassette 151 (the cassette from which the wafer 100 was removed).

[0031] The first control unit 7 includes a CPU that performs calculations according to a control program, and a storage medium such as memory. The first control unit 7 controls each component of the grinding apparatus 1 to perform grinding on the wafer 100. The following describes the method of processing the wafer 100 in the grinding apparatus 1 under the control of the first control unit 7.

[0032] (1) Holding step In the processing of wafer 100, first, the first control unit 7 controls the robot hand 155 shown in Figure 1 to take, for example, a wafer 100 before processing from the first cassette 150 and place it on the temporary storage unit 152. Furthermore, the first control unit 7 controls the loading unit 153 to hold the wafer 100 on the temporary storage unit 152 and place it on the holding surface 4 of the holding table 5 with the back surface 102 facing upwards. After that, the first control unit 7 connects the holding surface 4 to a suction source (not shown). As a result, the holding surface 4 holds the wafer 100 by suction via the protective tape 103. In this way, the wafer 100 is held by the holding table 5.

[0033] (2) Grinding step In this step, the first rough grinding unit 30 and the first finish grinding unit 31 grind the wafer 100 held on the holding table 5.

[0034] (2-1) Rough grinding step After the holding step, the first control unit 7 rotates the turntable 6 shown in Figure 1, thereby positioning the holding table 5, which is holding the wafer 100, below the first rough grinding unit 30.

[0035] The first control unit 7 rotates the grinding wheel 34 of the first rough grinding unit 30 and uses the vertical movement unit 50 to feed the first rough grinding unit 30 along the Z-axis direction (see Figure 3). Furthermore, the first control unit 7 rotates the holding table 5 using the table rotation support mechanism 3.

[0036] As a result, the rough grinding wheel 33 of the rotating grinding wheel 34 comes into contact with the back surface 102 of the wafer 100 held on the rotating holding table 5, and rough grinds this back surface 102.

[0037] Furthermore, the first control unit 7 measures the thickness of the wafer 100 using a thickness measuring device (not shown) while grinding with the rough grinding wheel 33. The first control unit 7 then performs grinding with the rough grinding wheel 33 until the thickness of the wafer 100 reaches a predetermined rough grinding thickness.

[0038] (2-2) Finishing grinding step In the finish grinding step, the surface of the wafer 100 that has been ground by the rough grinding wheel 33 is finished grinding. In this step, first, the first control unit 7 rotates the turntable 6 shown in Figure 1 to position the holding table 5 that holds the wafer 100 below the first finish grinding unit 31.

[0039] Then, similar to the rough grinding step, the first control unit 7 rotates the grinding wheel 34 and uses the vertical movement unit 50 to feed the first finish grinding unit 31 along the Z-axis direction. Furthermore, the first control unit 7 rotates the holding table 5 using the table rotation support mechanism 3.

[0040] As a result, the finishing grinding wheel 37 of the rotating grinding wheel 34 comes into contact with the back surface 102 of the wafer 100 held on the rotating holding table 5, and finish grinds the back surface 102.

[0041] Furthermore, the first control unit 7 measures the thickness of the wafer 100 using a thickness measuring instrument (not shown) while grinding with the finishing grinding wheel 37. The first control unit 7 then performs grinding with the finishing grinding wheel 37 until the thickness of the wafer 100 reaches a predetermined finishing grinding thickness.

[0042] (3) Energy supply step In this step, the first laser beam irradiation unit 40 irradiates the back surface 102 of the wafer 100, which is the grinding surface, with a laser beam to melt it, then cools and recrystallizes it, repairing at least some of the damage caused by grinding. The melting and re-solidification also has the effect of flattening the grinding surface. This damage (damage layer) is a processed alteration layer that includes, for example, cracks, scratches, and chips caused by grinding.

[0043] The configuration of the first laser beam irradiation unit 40 will now be described. The first laser beam irradiation unit 40 includes at least an oscillator that emits a laser beam and a focusing lens that focuses the laser beam, and emits a laser beam with a wavelength that is absorbed by the wafer 100, which is the workpiece.

[0044] In addition to the processing head 41 having a focusing lens, the first laser beam irradiation unit 40 includes, as shown in Figure 5, an oscillator 75 for emitting a laser beam, an X-axis direction diffuser 76, and a resonant scanner 77. These oscillator 75, X-axis direction diffuser 76, and resonant scanner 77 are housed within the housing 43 and processing head 41 of the first laser beam irradiation unit 40 shown in Figure 4.

[0045] The oscillator 75 emits a laser beam with a wavelength that is absorbed by the wafer 100. The X-axis disperser 76 includes an optical deflection element (AOD) 762 and a first mirror 761 that guides the laser beam from the oscillator 75 to the optical deflection element 762, thereby adjusting the position of the laser beam emitted from the oscillator 75 in the X-axis direction. The laser beam from the X-axis disperser 76 is guided to the resonant scanner 77 via a second mirror 78.

[0046] The resonant scanner 77 is equipped with a oscillating mirror 771 that reflects incident light, causing the laser beam's irradiation position (optical axis) to reciprocate along the Y-axis. By controlling the oscillating motion of the oscillating mirror 771, the resonant scanner 77 can reciprocate the laser beam's irradiation position along the Y-axis at any frequency and oscillation angle.

[0047] The laser beam from the resonant scanner 77 is guided to the fθ lens 79 in the processing head 41. The fθ lens 79 is a focusing lens that concentrates the laser beam. The fθ lens 79 irradiates the back surface 102, which is the grinding surface of the wafer 100 held on the holding surface 4 of the holding table 5, with the laser beam from the resonant scanner 77 as parallel laser beams 401 with equal focusing heights.

[0048] The first control unit 7 performs the energy supply step using the first laser beam irradiation unit 40 having the above configuration.

[0049] In other words, the first control unit 7 first rotates the turntable 6 shown in Figure 1 to position the holding table 5 that holds the wafer 100 below the first laser beam irradiation unit 40.

[0050] Next, the first control unit 7, in the first laser beam irradiation unit 40 shown in Figure 5, oscillates a laser beam from the oscillator 75 and controls the oscillation state of the oscillating mirror 771 in the resonant scanner 77, thereby irradiating the laser beam 401 output from the fθ lens 79 onto a long, narrow first range 402 from the center to the outer edge of the back surface 102 of the wafer 100, as shown in Figure 6.

[0051] Then, the first control unit 7 rotates the holding table 5 as shown by the arrow 501. As a result, the laser beam 401 from the fθ lens 79 of the first laser beam irradiation unit 40 irradiates the entire back surface 102 of the wafer 100, which is the grinding surface, and melts the entire back surface 102. In this embodiment, since the laser beam 401 has a wavelength that is absorbed by the wafer 100, not only the back surface 102 but also the portion from the back surface 102 to a predetermined thickness (the portion near the back surface) is melted. The portion near the back surface that is melted varies depending on the extent of damage, but for example, it is the portion with a thickness of 0.5 μm to 1.5 μm or 0.5 μm to 4 μm from the back surface 102.

[0052] Subsequently, the first control unit 7 stops irradiating with the laser beam 401. This allows the molten back surface 102 and the area near the back surface to cool and solidify.

[0053] (4) Washing step After the energy supply step, the first control unit 7 transports the wafer 100 to the first cleaning unit 156 using the unloading unit 154 shown in Figure 1, and cleans the wafer 100. The first control unit 7 then uses the robot hand 155 to load the cleaned wafer 100 into the first cassette 150 or the second cassette 151.

[0054] As described above, in this embodiment, after the grinding step, an energy supply step is performed to irradiate the back surface 102 of the wafer 100, which is the ground surface, with a laser beam to melt the back surface 102 and the surrounding area, including the damage caused by grinding. Furthermore, the back surface 102 and the surrounding area are then cooled and solidified.

[0055] In this embodiment, the melting and cooling process on the back surface 102 of the wafer 100 allows for crystal growth in the molten region of the back surface 102 and the surrounding area to form seed crystals, which are then recrystallized. Therefore, the back surface 102 can be flattened, and cracks and chips caused by grinding can be bonded to the back surface 102 and the surrounding area, making it possible to repair at least a portion of the damage to the surface 101 and the surrounding area. Furthermore, flattening increases the flexural strength of the wafer 100, reducing the risk of cracking or chipping in the wafer 100 in subsequent processes after the energy supply step, and increasing the flexural strength of the chip when it is chipped.

[0056] Here, one could consider polishing the ground surface with a polishing pad (CMP polishing or dry polishing) to treat the ground surface (flattening and repairing damage). However, CMP is a chemical treatment, and a configuration is needed to handle the liquid chemical. In addition, both CMP polishing and dry polishing remove a portion of the ground surface, generating polishing debris, which may adhere to the workpiece or contaminate the inside of the equipment. In contrast, the process of melting the wafer 100 with the first laser beam irradiation unit 40 to remove damage does not require liquid treatment and does not generate processing debris, thus simplifying the equipment and suppressing contamination of the workpiece and equipment.

[0057] Furthermore, in this embodiment, the grinding apparatus 1 is equipped with a first rough grinding unit 30, a first finish grinding unit 31, and a first laser beam irradiation unit 40 on a single apparatus base 10, and the wafer 100 is transported from the first rough grinding unit 30 and the first finish grinding unit 31 to the first laser beam irradiation unit 40 by a turntable 6. Therefore, within a single grinding apparatus 1, the wafer 100 can be ground by the first rough grinding unit 30 and the first finish grinding unit 31, and the damage to the wafer 100 caused by grinding can be easily and quickly repaired by the first laser beam irradiation unit 40. Thus, it is possible to efficiently and effectively perform the grinding and repair of damage to the wafer 100.

[0058] In this embodiment, the material of the wafer 100 as the workpiece is preferably a liquid-phase grown material such as Si, Ge, and GaAs. Liquid-phase grown materials melt easily when energy is supplied, such as by laser irradiation. Therefore, damage formed on the grinding surface of the wafer 100 can be effectively repaired by supplying energy such as laser irradiation.

[0059] Furthermore, in the above-described embodiment, the first laser beam irradiation unit 40 has a configuration that uses a resonant scanner 77 to move the irradiation position of the laser beam back and forth along the Y-axis. Alternatively, the first laser beam irradiation unit 40 may use a galvanometer scanner to move the irradiation position of the laser beam back and forth along the Y-axis.

[0060] Furthermore, in the above-described embodiment, a grinding apparatus 1 was described in which a first rough grinding unit 30, a first finish grinding unit 31, and a first laser beam irradiation unit 40 are provided on a single apparatus base 10. However, the apparatus is not limited to this, and the first rough grinding unit 30, the first finish 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 Figure 7 may be employed.

[0061] As shown in Figure 7, the processing system 2 includes a second rough grinding unit 38 for rough grinding the wafer 100, a second finish grinding unit 39 for finish 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. Furthermore, the processing system 2 includes a second control unit 8 that controls each component of the processing system 2.

[0062] The second rough grinding unit 38 and the second finish grinding unit 39 are equipped with a holding mechanism (such as a holding table) for holding the wafer 100 and have the same functions as the first rough grinding unit 30 and the first finish grinding unit 31 described above, and are configured to rough grind and finish grind the back surface 102 of the wafer 100, respectively.

[0063] Furthermore, the second laser beam irradiation unit 45 also has a holding mechanism for holding the wafer 100 and has the same functions as the first laser beam irradiation unit 40 described above, irradiating the grinding surface of the wafer 100 with a laser beam to melt it and repair at least a portion of the damage caused by grinding. This second laser beam irradiation unit 45, like the first laser beam irradiation unit 40, is an example of an energy supply unit.

[0064] Furthermore, the second cleaning unit 157 also cleans the wafer 100 in the same manner as the first cleaning unit 156. Furthermore, the cassette mounting unit 160 has third to sixth cassettes 161 to 164 for housing the wafers 100.

[0065] The first transport unit 90 includes a first guide rail 91 extending substantially parallel to the direction in which the third to sixth cassettes 161 to 164 are lined up, 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 take out and put into the third to sixth cassettes 161 to 164. In the first transport unit 90, the first robot 92 places the wafer 100 taken out from any of the third to sixth cassettes 161 to 164 onto, for example, an alignment unit (not shown).

[0066] The second transport unit 95 includes a second guide rail 96 and a second robot 97 that can move along the second guide rail 96. The second guide rail 96 extends substantially 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 aligned, and is positioned between them and the second finish grinding unit 39.

[0067] In the second transport unit 95, the wafer 100, which has been placed on the alignment unit (not shown) by the first robot 92 of the first transport unit 90, can be held by the second robot 97. Furthermore, in the second transport unit 95, the second robot 97 can transport the wafer 100 between the second rough grinding unit 38, the second finish grinding unit 39, the second laser beam irradiation unit 45, and the second cleaning unit 157. In other words, the second transport unit 95 can transport the wafer 100 from the second rough grinding unit 38 and the second finish grinding unit 39 to the second laser beam irradiation unit 45.

[0068] In a processing system 2 having such a configuration, the second control unit 8, which controls the processing system 2, uses the first transport unit 90 to take a wafer 100 from one of the third to sixth cassettes 161 to 164 and, via an alignment unit (not shown), has the second robot 97 of the second transport unit 95 hold the wafer 100. Then, using the second transport unit 95, the second control unit 8 moves the wafer 100 between the second rough grinding unit 38, the second finish grinding unit 39, the second laser beam irradiation unit 45, and the second cleaning unit 157, while performing the grinding step, energy supply step, and cleaning step described above on the wafer 100.

[0069] In this processing system 2, as with the grinding apparatus 1, the back surface 102 of the wafer 100 can be flattened and at least a portion of the damage to the back surface 102 and the area near the back surface can be repaired by the melting and cooling process performed by the second laser beam irradiation unit 45.

[0070] Furthermore, in the processing system 2, the wafer 100 can be transported from the second rough grinding unit 38 and the second finish grinding unit 39 to the second laser beam irradiation unit 45 by the second transport unit 95. Therefore, within a single processing system 2, the wafer 100 can be ground by the second rough grinding unit 38 and the second finish grinding unit 39, and the damage to the wafer 100 caused by grinding can be easily and quickly repaired by the second laser beam irradiation unit 45. Thus, it is possible to efficiently and effectively perform the grinding and repair of damage to the wafer 100.

[0071] Furthermore, in processing system 2, the configuration shown in Figure 8 can be used as the second laser beam irradiation unit 45. When using the second laser beam irradiation unit 45 shown in Figure 8, in processing system 2, the wafer 100 is treated as a workset 110 including, for example, a ring frame 111, adhesive tape 113, and the wafer 100.

[0072] The second laser beam irradiation unit 45 shown in Figure 8 is equipped with a base 115, and the upper surface of the base 115 is equipped with a holding table section 140 with a holding table 143, an X-axis movement mechanism 120 for moving the holding table 143 in the X-axis direction, and a Y-axis movement mechanism 130 for moving the holding table 143 in the Y-axis direction.

[0073] The X-axis movement mechanism 120 moves the holding table 143 in the X-axis direction relative to the machining head 41. The X-axis movement mechanism 120 includes a pair of guide rails 123 extending in the X-axis direction, an X-axis table 124 mounted on the guide rails 123, a ball screw 125 extending parallel to the guide rails 123, and a drive motor 126 for rotating the ball screw 125.

[0074] A pair of guide rails 123 are positioned on the upper surface of the base 115, parallel to the X-axis direction. The X-axis table 124 is mounted 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 mounted on the X-axis table 124.

[0075] The ball screw 125 is screwed into a nut (not shown) provided on the X-axis table 124. The drive motor 126 is connected to one end of the ball screw 125 and rotates the ball screw 125. As the ball screw 125 rotates, the X-axis table 124, the Y-axis movement mechanism 130, and the holding table section 140 move in the X-axis direction along the guide rail 123.

[0076] The Y-axis movement mechanism 130 moves the holding table 143 in the X-axis direction relative to the machining head 41. The Y-axis movement mechanism 130 includes a pair of guide rails 131 extending in the Y-axis direction, a Y-axis table 132 mounted on the guide rails 131, a ball screw 133 extending parallel to the guide rails 131, and a drive motor 135 for rotating the ball screw 133.

[0077] A pair of guide rails 131 are positioned parallel to the Y-axis direction on the upper surface of the X-axis table 124. The Y-axis table 132 is mounted on the pair of guide rails 131 so as to be slidable along these guide rails 131. A holding table section 140 is placed on the Y-axis table 132.

[0078] The ball screw 133 is screwed into a nut portion (not shown) provided on the Y-axis table 132. The drive motor 135 is connected to one end of the ball screw 133 and rotates the ball screw 133. As the ball screw 133 rotates, the Y-axis table 132 and the holding table portion 140 move in the Y-axis direction along the guide rail 131.

[0079] The holding table section 140 includes a holding table 143 for holding the wafer 100, a clamp section 145 provided around the holding table 143, a support column 147 for supporting the holding table 143, and a cover plate 146 provided at the upper end of the support column 147 so as to surround the holding table 143.

[0080] A holding surface 144 made of porous material is formed on the upper surface of the holding table 143. This holding surface 144 is connected to a suction source (not shown), making it possible to hold the wafer 100 in the workset 110 by suction.

[0081] Four clamping portions 145 are provided around the holding table 143. The four clamping portions 145 clamp and secure the ring frame 111 surrounding the wafer 100 held by the holding table 143 from all four sides.

[0082] Furthermore, the second laser beam irradiation unit 45 is mounted on the base 115 and includes a housing 116 having a processing head 41 and a camera 42.

[0083] The housing 116 incorporates, for example, the oscillator 75, the X-axis disperser 76, the second mirror 78, and the resonant scanner 77 shown in Figure 5. The processing head 41 also has the fθ lens 79 shown in Figure 5. As a result, the second laser beam irradiation unit 45, like the first laser beam irradiation unit 40, can emit a laser beam of an absorbing wavelength to the wafer 100 held on the holding table 143 of the holding table section 140.

[0084] In the processing system 2 equipped with the second laser beam irradiation unit 45 having such a configuration, the second control unit 8 emits a laser beam from the oscillator 75 shown in Figure 5 and irradiates the back surface 102 of the wafer 100 held on the holding table 143 with the laser beam 401 from the fθ lens 79 of the processing head 41.

[0085] At this time, as shown in Figure 9, the second control unit 8 controls the X-axis movement mechanism 120 to irradiate the laser beam 401 to the -X side edge of the back surface 102 of the wafer 100. At this time, the second control unit 8 controls the oscillation state of the oscillating mirror 771 in the resonant scanner 77 to set 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.

[0086] Furthermore, the second control unit 8 controls the X-axis movement mechanism 120 (see Figure 8) to move the holding table 143 that holds the wafer 100 along the -X direction. As a result, the first range 405 moves relatively in the +X direction on the back surface 102 of the wafer 100, as shown by the arrow 510 in Figure 9. At this time, the length of the first range 405, which is the irradiation range of the laser beam 401, is appropriately set to be longer than the length of the wafer 100 in the Y-axis direction in the part where the first range 405 is located.

[0087] In this way, the laser beam 401 is irradiated from the fθ lens 79 of the second laser beam irradiation unit 45 onto the entire back surface 102 of the wafer 100, which is the grinding surface, causing the entire back surface 102 to melt. As a result, the back surface 102 is flattened, and at least a portion of the damage to the back surface 102 and the area near the back surface is repaired. The length of the first range 405 may be set to be longer than the diameter of the wafer 100, regardless of the position of the first range 405 on the wafer 100.

[0088] Furthermore, the processing system 2 shown in Figure 7 may have a transport system 200 as shown in Figure 10 instead of the first transport unit 90 and the second transport unit 95.

[0089] The transport system 200 is an example of a transport unit and includes a travel rail 205. The travel rail 205 is installed across the units shown in Figure 7, such as the second rough grinding unit 38, the second finish grinding unit 39, the second laser beam irradiation unit 45, the second cleaning unit 157, and the cassette mounting unit 160, so that wafers 100 can be transported to these units. In other words, these units are connected to each other via the travel rail 205. The travel rail 205 is also positioned above the housings 250 of these units, as shown in Figure 10.

[0090] Furthermore, the transport system 200 includes a tray 210 for accommodating a workset 110 containing wafers 100, and an automated guided vehicle 215 for transporting the tray 210. The automated guided vehicle 215 travels along the travel rail 205 while holding the tray 210 containing the workset 110, thereby enabling the transport of the workset 110, including wafers 100, between each unit. In other words, the transport system 200 uses the automated guided vehicle 215 to transport wafers 100 from the second rough grinding unit 38 and the second finish grinding unit 39 to the second laser beam irradiation unit 45.

[0091] An opening 255 is provided at the corner of the top plate 251 of the housing 250 of each unit. The housing 250 is also provided with a tray support base 260 for supporting the tray 210. The tray support base 260 is raised and lowered by a lifting mechanism (not shown) so that it passes through the opening 255 while supporting the tray 210.

[0092] Furthermore, the transport system 200 has a tray transport arm 220 located near the opening 255. The tray transport arm 220 transports the tray 210 between a tray support base 260 positioned at the same height as the opening 255 and an automated guided vehicle 215 stopped near the opening 255.

[0093] Therefore, by stopping an automated guided vehicle 215 holding a tray 210 containing a workset 110 near the housing 250 of each unit, transferring the tray 210 to the tray support base 260 of the housing 250 using a tray transfer arm 220, and lowering the tray support base 260 using a lifting mechanism (not shown), it is possible to load the workset 110, including the wafer 100, into the housing 250.

[0094] Furthermore, the workset 110, including the processed wafer 100, is placed in a tray 210 within the housing 250 of each unit. This tray 210 is supported by a tray support base 260, raised to the opening 255 by a lifting mechanism, and then handed over to an automated guided vehicle 215 by a tray transport arm 220, thereby enabling the workset 110 to be transported to other units.

[0095] When using such a transport system 200, the second control unit 8 moves the wafer 100 between the second rough grinding unit 38, the second finish grinding unit 39, the second laser beam irradiation unit 45, the second cleaning unit 157, and the cassette mounting unit 160 using the transport system 200, while performing the grinding step, energy supply step, and cleaning step described above on the wafer 100.

[0096] Therefore, even in this case, the back surface 102 of the wafer 100, which is the grinding surface, is flattened by laser irradiation by the second laser beam irradiation unit 45, and at least a portion of the damage to the back surface 102 and the area near the back surface is repaired.

[0097] Furthermore, the transport system 200 can transport the wafer 100 from the second rough grinding unit 38 and the second finish grinding unit 39 to the second laser beam irradiation unit 45. Therefore, within a single processing system 2, the wafer 100 can be ground by the second rough grinding unit 38 and the second finish grinding unit 39, and the damage to the wafer 100 caused by grinding can be easily and quickly repaired by the second laser beam irradiation unit 45. Thus, it is possible to efficiently and effectively perform the grinding and repair of damage to the wafer 100.

[0098] Furthermore, as described above, the oscillator 75 of the first laser beam irradiation unit 40 shown in Figure 5 emits a laser beam with a wavelength that is absorbed by the wafer 100. For example, if the wafer 100 is a silicon wafer, the wavelength of the laser beam emitted from the oscillator 75 is in the range of 500 to 1000 nm, which is a wavelength that is absorbed by silicon.

[0099] Figure 11 is a table showing the relationship between the wavelength of the laser beam emitted from the oscillator 75 and the results (processing results) of the energy supply steps performed using each laser beam. As shown in this table, when the wavelength was in the range of 500 to 1000 nm, it was possible to successfully melt the back surface 102 and the area near the back surface, which are the grinding surfaces of the silicon wafer 100.

[0100] On the other hand, when the wavelength was 355 nm or less, it was difficult to sufficiently melt the back surface 102 and the area near the back surface of the silicon wafer 100, which is the grinding surface. Also, when the wavelength was 1064 nm, the laser beam passed through the wafer 100, making it difficult to properly melt the back surface 102 and the area near the back surface.

[0101] In the energy supply step, 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 and repair 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 the wafer 100 (workpiece) in the vacuum chamber, and a plasma supply unit that supplies plasma-like gas to the wafer 100 held on the holding table. [Explanation of Symbols]

[0102] 1: Grinding device, 2: Processing system, 3: Table rotation support mechanism, 4: Holding surface, 5: Holding table, 6: Turntable, 7: First control unit, 8: Second control unit, 10: Device base, 11: Column, 30: First rough grinding unit, 31: First finishing grinding unit, 33: Rough grinding wheel, 34: Grinding wheel, 35: Spindle, 37: Finishing grinding wheel, 38: Second rough grinding unit, 39: Second finishing grinding unit, 40: First laser beam irradiation unit, 41: Machining head 42: Camera, 43: Housing, 45: Second laser beam irradiation unit, 50: Vertical movement unit, 51: Z-axis guide rail, 52: Holding plate, 75: Oscillator, 76: X-axis disperser, 77: Resonant scanner, 78: Second mirror, 79: fθ lens, 90: first transport unit, 91: first guide rail, 92: First robot, 95: Second transport unit, 96: Second guide rail, 97: Second robot, 100: Wafer, 101: Front side, 102: Back side, 103: Protective tape, 110: Workset, 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: Holding table section, 143: Holding table, 144: Holding surface, 145: Clamp section 146: Cover plate, 147: Support column, 150: First cassette, 151: Second cassette, 152: Temporary storage unit, 153: Delivery unit, 154: Delivery unit, 155: Robot hand, 156: First washing unit, 157: Second washing unit, 160: Cassette mounting unit, 161: 6th cassette, 162: 6th cassette, 163: The 6th cassette, 164: The 6th cassette, 200: Conveyor system, 205: Running rail, 210: Tray, 215: Automated guided vehicle, 220: Tray transport arm 250: Enclosure, 251: Top panel, 255: Opening, 260: Tray support base, 401: Laser beam, 402: First range, 405: First range, 761: First mirror, 762: Optical deflection element, 771: Oscillating mirror

Claims

1. A grinding unit for grinding a workpiece includes a grinding wheel and a spindle that rotatably supports the grinding wheel, An energy supply unit that supplies energy to the ground surface of a workpiece ground by the grinding unit to melt it and repair at least a portion of the damage caused by grinding, The system includes a conveying unit that transports the workpiece from the grinding unit to the energy supply unit, The energy supply unit is a laser beam irradiation unit that includes at least an oscillator that emits a laser beam and a focusing lens that focuses the laser beam, and irradiates with a laser beam. The laser beam irradiation unit is configured to irradiate the grinding surface of a rotating workpiece with a laser beam that extends from the center to the outer edge of the circular grinding surface of the workpiece. Processing system.

2. A grinding unit for grinding a workpiece includes a grinding wheel and a spindle that rotatably supports the grinding wheel, An energy supply unit that supplies energy to the ground surface of a workpiece ground by the grinding unit to melt it and repair at least a portion of the damage caused by grinding, The system includes a conveying unit that transports the workpiece from the grinding unit to the energy supply unit, The energy supply unit is a laser beam irradiation unit that includes at least an oscillator that emits a laser beam and a focusing lens that focuses the laser beam, and irradiates with a laser beam. The laser beam irradiation unit is configured to irradiate the grinding surface of a workpiece moving in a second direction perpendicular to the first direction with a laser beam having an elongated irradiation range extending in a first direction, wherein the length of the irradiation range of the laser beam in the first direction is longer than the length of the portion of the workpiece in the first direction where the irradiation range is located. Processing system.

3. The laser beam irradiation unit is equipped with a resonant scanner or galvanometer scanner for forming the irradiation area of ​​the laser beam. The processing system according to claim 1 or 2.

4. The laser beam irradiation unit is characterized by irradiating the workpiece with a laser beam of a wavelength that has absorption properties. A processing system according to any one of claims 1 to 3.

5. The wavelength of the laser beam is characterized by being in the range of 500 to 1000 nm. A processing system according to any one of claims 1 to 4.

6. The material of the workpiece is characterized by being a material grown in the liquid phase. A processing system according to any one of claims 1 to 5.

7. The transport unit is a turntable that rotatably supports a holding table that holds the workpiece, The rotation of the turntable is characterized by moving the holding table that holds the workpiece from the grinding unit to the energy supply unit. The processing system according to any one of claims 1 to 6.

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