SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS

Abstract

A substrate processing method comprising: preparing a substrate having a first main surface and a second main surface opposite to the first main surface and having waviness in each of the first main surface and the second main surface; irradiating the first main surface with a first laser beam to reduce the waviness in the first main surface; and irradiating, after having reduced the waviness in the first main surface, the first main surface with a second laser beam different from the first laser beam to reduce the surface roughness of the first main surface.

Description

Substrate processing method, substrate processing apparatus, and grinding apparatus

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a grinding apparatus.

[0002] Patent Document 1 describes a semiconductor wafer processing method in which semiconductor wafers obtained by slicing a single crystal ingot are subjected to a chamfering step, a lapping step, an etching step, and a mirror polishing step.

[0003] Japanese Patent Application Publication No. 2002-203823

[0004] One aspect of the present disclosure provides a technique for increasing the number of substrates processed per unit time.

[0005] A substrate processing method according to one aspect of the present disclosure includes: preparing a substrate having a first main surface and a second main surface facing opposite to the first main surface, the first main surface and the second main surface each having waviness; irradiating the first main surface with a first laser beam to reduce the waviness of the first main surface; and after reducing the waviness of the first main surface, irradiating the first main surface with a second laser beam different from the first laser beam to reduce surface roughness of the first main surface.

[0006] According to one aspect of the present disclosure, the number of substrates that can be processed per unit time can be increased.

[0007] FIG. 1 is a flowchart showing a substrate processing method according to an embodiment. FIG. 2A is a cross-sectional view showing an example of step S101, FIG. 2B is a cross-sectional view showing an example of step S102, and FIG. 2C is a cross-sectional view showing an example of step S103. FIG. 3A is a cross-sectional view showing an example of step S107, and FIG. 3B is a cross-sectional view showing an example of step S109. FIG. 4 is a plan view showing a substrate processing apparatus according to an embodiment. FIG. 5 is a flowchart showing a substrate processing method according to a first modified example. FIG. 6 is a plan view showing a substrate processing apparatus according to the first modified example. FIG. 7 is a flowchart showing a substrate processing method according to a second modified example. FIG. 8 is a plan view showing a substrate processing apparatus according to the second modified example.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0009] A substrate processing method according to one embodiment will be described with reference to Figures 1 to 3. The substrate processing method includes steps S101 to S104 and S107 to S109 shown in Figure 1. Steps S105 to S106 will be described later.

[0010] 1 , or may further include steps not shown. An example of a step not shown is cleaning of the substrate W. Cleaning of the substrate W is performed after laser processing of the substrate W or grinding of the substrate W. Etching of the substrate W may also be performed as a step not shown. A cleaning device for cleaning the substrate W and an etching device for etching the substrate W can be provided in the substrate processing apparatus 1 described below.

[0011] Step S101 includes preparing a substrate W. Preparing the substrate W includes, for example, loading the substrate W into a substrate processing apparatus 1 (see FIG. 4 , etc.) described below. The substrate W is loaded into the substrate processing apparatus 1 while being accommodated in a cassette C. The substrate W is a silicon wafer or a compound semiconductor wafer. The compound semiconductor wafer is not particularly limited, but may be, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer. The substrate W is a bare wafer.

[0012] The substrate W is, for example, disk-shaped. The substrate W may include a bevel on its periphery. As shown in FIG. 2A , the substrate W includes a first main surface Wa and a second main surface Wb facing opposite to the first main surface Wa. The first main surface Wa and the second main surface Wb are formed by slicing a single crystal ingot. Therefore, the substrate W has waviness on each of the first main surface Wa and the second main surface Wb.

[0013] The waviness of each of the first main surface Wa and the second main surface Wb is measured in advance using a measuring device. The measuring device may be a contact type or a non-contact type. A commercially available three-dimensional measuring machine is used as the measuring device. The measuring device measures the height distribution of the upper surface of the substrate W. The measuring device may also measure the height distribution of both the upper surface and the lower surface of the substrate W simultaneously. The reference plane for the height is, for example, a horizontal plane. The reference plane for the height may be a crystal plane expressed by desired Miller indices, or a plane inclined from that crystal plane by a desired off-angle.

[0014] Step S102 includes irradiating the first main surface Wa with a first laser beam LB1 as shown in FIG. 2B based on the measurement results of the waviness of the first main surface Wa to reduce the waviness of the first main surface Wa. The magnitude of the waviness is expressed, for example, by the maximum height difference in a direction perpendicular to a height reference plane. Step S102 also includes flattening the first main surface Wa.

[0015] Step S102 includes forming an irradiation point P1 of the first laser beam LB1 on the first principal surface Wa and moving the position of the irradiation point P1 within the first principal surface Wa. A galvanometer scanner, an XY stage, an XYθ stage, or the like is used to move the irradiation point P1. The first laser beam LB1 may be irradiated onto the entire first principal surface Wa, or onto only a portion of the first principal surface Wa. Even in the latter case, it is possible to flatten the first principal surface Wa.

[0016] The surface layer of the first principal surface Wa absorbs the first laser beam LB1 and either changes state from solid to gaseous and disperses, or disperses while remaining in the solid state. This removes the surface layer. The amount of removal (removal depth) varies depending on the location within the first principal surface Wa. The amount of removal can be controlled by the number of times the first laser beam LB1 is irradiated. The more times the irradiation is performed, the greater the amount of removal. The number of irradiations is the number of times the irradiation point P1 passes through.

[0017] In step S102, the amount of removal per irradiation is not particularly limited, but is, for example, greater than 0.1 μm to 1.0 μm. If the amount of removal per irradiation is greater than 0.1 μm, fewer irradiations are required, and the time required for laser processing is shorter. Furthermore, if the amount of removal per irradiation is 1.0 μm or less, fine height adjustment is possible, and the amount of waviness after laser processing is small.

[0018] Step S103 includes irradiating the first principal surface Wa with a second laser beam LB2 to reduce the surface roughness Ra of the first principal surface Wa, as shown in FIG. 2C. The surface roughness Ra refers to the arithmetic mean roughness as defined in JIS B0601:2013. The second laser beam LB2 is different from the first laser beam LB1. Step S103 removes a smaller amount of material per irradiation than step S102. This allows for more precise height adjustment. In step S103, the amount of material removed per irradiation is not particularly limited, but is, for example, 0.01 μm to 0.1 μm.

[0019] In order to differentiate the amount of removal per irradiation in step S102 and step S103, the fluence (J / cm ２ The greater the fluence, the greater the amount of removal per irradiation. The first laser beam LB1 has a fluence (J / cm) greater than the second laser beam LB2. ２ The fluence can be adjusted by the spot diameter, the number of bursts, the laser output, or the like. The first laser beam LB1 has a larger fluence (J / cm) than the second laser beam LB2. ２ ) is increased by setting the spot diameter to be small, the number of bursts to be large, or the laser output to be large.

[0020] Step S103 includes forming an irradiation point P2 of the second laser beam LB2 on the first principal surface Wa and moving the position of the irradiation point P2 within the first principal surface Wa. A galvanometer scanner, an XY stage, an XYθ stage, or the like is used to move the irradiation point P2. The second laser beam LB2 may be irradiated onto the entire first principal surface Wa, or onto only a portion of the first principal surface Wa.

[0021] However, if the second laser beam LB2 is irradiated onto the entire first principal surface Wa, the surface roughness Ra can be made uniform over the entire first principal surface Wa. In step S102, it is more effective to irradiate only a portion of the first principal surface Wa with the first laser beam LB1 and not irradiate the remaining portion of the first principal surface Wa with the first laser beam LB1. This is because in this case, a difference in surface roughness Ra occurs between the portion and the remaining portion of the first principal surface Wa.

[0022] The surface layer of the first principal surface Wa absorbs the second laser beam LB2 and either changes state from a solid phase to a gas phase and scatters, or scatters while remaining in the solid phase. This removes the surface layer. In step S103, the removal amount (removal depth) may be the same regardless of the location within the first principal surface Wa, but it is preferable that it differs depending on the location to further reduce waviness. The removal amount can be controlled by the number of times the second laser beam LB2 is irradiated. The more the number of times the irradiation is performed, the greater the removal amount. The number of times the irradiation is performed is the number of times the irradiation point P2 passes through.

[0023] According to this embodiment, in step S102, the first main surface Wa is roughly processed using the first laser beam LB1, which has a high processing speed (a large amount of removal per irradiation), and then in step S103, the first main surface Wa is precisely processed using the second laser beam LB2, which has a low processing speed (a small amount of removal per irradiation). This makes it possible to increase the number of substrates W processed per unit time while maintaining processing precision.

[0024] Step S104 includes inverting the substrate W. Step S104 includes inverting the substrate W upside down so that the first main surface Wa of the substrate W faces downward and the second main surface Wb of the substrate W faces upward. Steps S105 to S106 following step S104 will be described later. In this embodiment, steps S105 to S106 are not performed.

[0025] 3A, step S107 includes grinding the second main surface Wb with a tool D in a state in which the first main surface Wa, which has been irradiated with the second laser beam LB2, is held by the suction surface 54a of the chuck 54. The tool D includes a grinding stone.

[0026] The second main surface Wb can be flattened by grinding it with the tool D. In this embodiment, the second main surface Wb is not laser processed before grinding and has waviness. The second main surface Wb can be flattened by grinding it parallel to the first main surface Wa, which has been flattened in advance in steps S102 and S103.

[0027] If steps S102 and S103 are not performed and the suction surface 54a of the chuck 54 suctions the first main surface Wa while the first main surface Wa is in a wavy state, the first main surface Wa will be flattened along the suction surface 54a. In this state, if the second main surface Wb is ground parallel to the first main surface Wa and the suction of the substrate W is then released, not only will the first main surface Wa return to a wavy state, but the second main surface Wb will also have the same wavy state as the first main surface Wa.

[0028] According to this embodiment, the second main surface Wb can be planarized by grinding the second main surface Wb parallel to the first main surface Wa, which has been planarized in advance. Furthermore, compared to planarizing both surfaces of the substrate W with a laser beam, waviness present on both surfaces of the substrate W can be removed in a shorter time. This is because the processing speed of laser processing is slower than that of grinding processing.

[0029] Step S108 includes turning over the substrate W. Step S108 includes turning over the substrate W upside down so that the first main surface Wa of the substrate W faces upward and the second main surface Wb of the substrate W faces downward.

[0030] 3B, step S109 includes grinding the first main surface Wa with the tool D while the ground second main surface Wb is held by the suction surface 54a of the chuck 54. The processing quality of the first main surface Wa and the second main surface Wb can be made equivalent. Because the first main surface Wa has been planarized in steps S102 and S103, the amount of grinding of the first main surface Wa is less than the amount of grinding of the second main surface Wb.

[0031] According to this embodiment, by reducing the surface roughness Ra of the first main surface Wa before grinding the first main surface Wa, it is possible to reduce wear of the grinding wheel when grinding the first main surface Wa. Furthermore, according to this embodiment, by uniforming the surface roughness Ra of the first main surface Wa before grinding the first main surface Wa, it is possible to uniformize the biting of the grinding wheel when grinding the first main surface Wa.

[0032] Next, a substrate processing apparatus 1 according to one embodiment will be described with reference to Fig. 4. In Fig. 4, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is vertical.

[0033] The substrate processing apparatus 1 includes a loading / unloading station 2, a first processing station 3, a second processing station 5, and a control device 9. The loading / unloading station 2, the first processing station 3, and the second processing station 5 are arranged in this order from the negative side in the X-axis direction to the positive side in the X-axis direction.

[0034] The loading / unloading station 2 includes a mounting table 20, a third transport area 21, and a third transport device 22. A plurality of cassettes C are placed on the mounting table 20. Each cassette C accommodates a plurality of substrates W. The number of cassettes C is not particularly limited.

[0035] The third transfer region 21 is adjacent to the mounting table 20 and the transition device 33 of the first processing station 3. The third transfer device 22 transfers substrates between multiple devices adjacent to the third transfer region 21. The third transfer device 22 has a transfer arm that holds the substrate W and a drive unit that moves or rotates the transfer arm. The transfer arm is capable of moving horizontally (in both the X-axis and Y-axis directions) and vertically, and of rotating about a vertical axis. Multiple transfer arms may be provided.

[0036] The first processing station 3 includes a first transfer region 31, a first transfer device 32, a transition device 33, a first laser processing device 34, a second laser processing device 35, and an inversion device 36. The arrangement and number of devices constituting the first processing station 3 are not limited to those shown in FIG.

[0037] The first transfer region 31 is adjacent to a transition device 33, a first laser processing device 34, a second laser processing device 35, and an inversion device 36. The first transfer device 32 transfers substrates between multiple devices adjacent to the first transfer region 31. The first transfer device 32 has a transfer arm that holds the substrate W and a drive unit that moves or rotates the transfer arm. The transfer arm is capable of moving horizontally (in both the X-axis and Y-axis directions) and vertically, and of rotating about a vertical axis. Multiple transfer arms may be provided.

[0038] The transition device 33 relays substrates W between the third transport device 22 of the loading / unloading station 2 and the first transport device 32 of the first processing station 3. Different transition devices 33 may be provided for relaying substrates W from the third transport device 22 to the first transport device 32 and for relaying substrates W from the first transport device 32 to the third transport device 22.

[0039] The first laser processing device 34 irradiates the first main surface Wa with a first laser beam LB1 based on the measurement results of the waviness of the first main surface Wa of the substrate W, thereby reducing the waviness of the first main surface Wa. After the waviness of the first main surface Wa has been reduced by the first laser processing device 34, the second laser processing device 35 irradiates the first main surface Wa with a second laser beam LB2 different from the first laser beam LB1, thereby reducing the surface roughness Ra of the first main surface Wa.

[0040] The inverting device 36 inverts the substrate W upside down.

[0041] The second processing station 5 includes a second transfer device 51, a grinding device 52, a transition device 56, and an inversion device 57. The arrangement and number of devices constituting the second processing station 5 are not limited to those shown in FIG.

[0042] The second transport device 51 transports the substrate W inside the second processing station 5. The second transport device 51 has a suction pad that holds the substrate W and a drive unit that moves or rotates the suction pad. The suction pad can move horizontally (in both the X-axis direction and the Y-axis direction) and vertically, and can rotate about a vertical axis. Multiple suction pads may be provided.

[0043] The grinding device 52 includes, for example, a rotary table 53, four chucks 54A, 54B, 54C, and 54D, and two tool driving units 55A and 55B. The chucks 54A, 54B, 54C, and 54D adsorb the substrate W onto their adsorption surfaces. The tool driving units 55A and 55B drive a tool D that is pressed against the substrate W. The tool D is rotated and raised and lowered.

[0044] The rotary table 53 is rotated around a rotation center line R1. The four chucks 54A to 54D are rotated together with the rotary table 53. The four chucks 54A to 54D are provided at intervals around the rotation center line R1 of the rotary table 53 and are rotated together with the rotary table 53. When the rotation of the rotary table 53 is stopped, the four chucks 54A to 54D can independently rotate around their respective rotation center lines.

[0045] The two chucks 54A, 54C are arranged symmetrically about the rotation center line R1 of the turntable 53. Each of the chucks 54A, 54C moves between a first load / unload position A3, where the second transport device 51 loads / unloads the substrate W, and a first processing position A1, where the substrate W is processed by one tool driving unit 55A. The two chucks 54A, 54C move between the first load / unload position A3 and the first processing position A1 every time the turntable 53 rotates 180°.

[0046] The other two chucks 54B, 54D are arranged symmetrically about the rotation center line R1 of the turntable 53. Each of the chucks 54B, 54D moves between a second load / unload position A0, where the second transport device 51 loads / unloads the substrate W, and a second processing position A2, where the substrate W is processed by another tool driving unit 55B. The other two chucks 54B, 54D move between the second load / unload position A0 and the second processing position A2 every time the turntable 53 rotates 180°.

[0047] When viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first processing position A1, and the second processing position A2 are arranged in this order in a counterclockwise direction. In this case, when viewed from above, the chucks 54A, 54B, 54C, and 54D are arranged in this order at 90° intervals in a counterclockwise direction.

[0048] The positions of the first loading / unloading position A3 and the second loading / unloading position A0 may be reversed, and the positions of the first processing position A1 and the second processing position A2 may also be reversed. That is, when viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first processing position A1, and the second processing position A2 may be arranged in this order clockwise. In this case, when viewed from above, the chucks 54A, 54B, 54C, and 54D are arranged in this order clockwise at 90° intervals.

[0049] However, the number of chucks is not limited to four, and the number of tool driving units is not limited to two. Also, the rotary table 53 may be omitted. Instead of the rotary table 53, a slide table may be provided.

[0050] The transition device 56 temporarily waits for the substrate W. The transition device 56 relays the substrate W between the first transport device 32 and the second transport device 51. Different transition devices 56 may be provided for relaying the substrate W from the first transport device 32 to the second transport device 51 and for relaying the substrate W from the second transport device 51 to the first transport device 32.

[0051] The inverting device 57 turns upside down the substrate W. Similar to the transition device 56, the inverting device 57 may relay the substrate W between the first transport device 32 and the second transport device 51.

[0052] The control device 9 is, for example, a computer, and includes an arithmetic unit 91 such as a CPU (Central Processing Unit), and a storage unit 92 such as a memory. The storage unit 92 stores programs for controlling various processes executed in the substrate processing apparatus 1. The control device 9 controls the operation of the substrate processing apparatus 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92. A unit controller for controlling the operation of each unit constituting the substrate processing apparatus 1 may be provided, and a system controller for overall control of multiple unit controllers may be provided. The control device 9 may be configured with the unit controllers and the system controller.

[0053] Next, the operation of the substrate processing apparatus 1 having the above configuration will be described with reference to Fig. 1 again. Steps S101 to S104 and S107 to S109 shown in Fig. 1 are performed under the control of the control device 9.

[0054] First, a transport device (not shown) loads a substrate W into the substrate processing apparatus 1 (step S101). The substrate W is placed on the mounting table 20 while being accommodated in a cassette C. Next, the third transport device 22 removes the substrate W from the cassette C on the mounting table 20 and transports it to the transition device 33. Subsequently, the first transport device 32 in the first processing station 3 removes the substrate W from the transition device 33 and transports it to the first laser processing device 34.

[0055] Next, the first laser processing device 34 irradiates the first main surface Wa with a first laser beam LB1 based on the measurement result of the waviness of the first main surface Wa of the substrate W, thereby reducing the waviness of the first main surface Wa (step S102). Thereafter, the first transport device 32 takes the substrate W out of the first laser processing device 34 and transports it to the second laser processing device 35.

[0056] Next, the second laser processing device 35 irradiates the first principal surface Wa with the second laser beam LB2 to reduce the surface roughness Ra of the first principal surface Wa (step S103). Thereafter, the first transport device 32 takes the substrate W out of the second laser processing device 35 and transports it to the reversing device 36.

[0057] Next, the inversion device 36 inverts the substrate W upside down so that the first main surface Wa of the substrate W faces downward and the second main surface Wb of the substrate W faces upward (step S104). Thereafter, the first transport device 32 takes out the substrate W from the inversion device 36 and transports it to the transition device 56 of the second processing station 5. Subsequently, the second transport device 51 takes out the substrate W from the transition device 56 and transports it to the grinding device 52. The substrate W is attracted to the suction surface of the chuck 54A or 54C at the first load / unload position A3, and then moved from the first load / unload position A3 to the first processing position A1.

[0058] Next, the grinding device 52 grinds the second main surface Wb while the first main surface Wa is held by the suction surface of the chuck 54A or 54C (step S107). At the first processing position A1, the tool driving unit 55A grinds the second main surface Wb of the substrate W. The substrate is then moved from the first processing position A1 to the first carry-in / out position A3. The second transport device 51 then removes the substrate W from the grinding device 52 and transports it to the inversion device 57.

[0059] Next, the inverting device 57 inverts the substrate W upside down so that the first main surface Wa of the substrate W faces upward and the second main surface Wb of the substrate W faces downward (step S108). Thereafter, the second transport device 51 takes the substrate W out of the inverting device 57 and transports it to the grinding device 52. The substrate W is attracted to the suction surface of the chuck 54B or 54D at the second load / unload position A0, and then moved from the second load / unload position A0 to the second processing position A2.

[0060] Next, the grinding device 52 grinds the first main surface Wa while the second main surface Wb is held by the suction surface of the chuck 54B or 54D (step S109). At the second processing position A2, the tool driving unit 55B grinds the first main surface Wa of the substrate W. The substrate is then moved from the second processing position A2 to the second load / unload position A0. The second transport device 51 then removes the substrate W from the grinding device 52 and transports it to the transition device 56.

[0061] Thereafter, the first transport device 32 takes out the substrate W from the transition device 56 and transports it to the transition device 33. Next, the third transport device 22 takes out the substrate W from the transition device 33 and stores it in the cassette C on the mounting table 20. Finally, a transport device (not shown) unloads the substrate W stored in the cassette C from the substrate processing apparatus 1.

[0062] According to this embodiment, the first laser processing device 34 and the second laser processing device 35 are provided separately. This allows the reduction of waviness on the first main surface Wa of one substrate W (step S102) and the reduction of the surface roughness Ra of the first main surface Wa of another substrate W (step S103) to be performed simultaneously. This allows the number of substrates W processed per unit time to be increased.

[0063] Furthermore, according to this embodiment, tool driving units 55A and 55B are provided separately, so that grinding of the second main surface Wb of one substrate W (step S107) and grinding of the first main surface Wa of another substrate W (step S109) can be performed simultaneously, thereby increasing the number of substrates W processed per unit time.

[0064] In this embodiment, the first processing station 3 and the second processing station 5 are provided in one substrate processing apparatus 1, but they may also be provided in separate substrate processing apparatuses. That is, a first substrate processing apparatus including the first processing station 3 and a second substrate processing apparatus including the second processing station 5 may be provided separately. In this case, the substrate W is subjected to reduction of at least the waviness of the first main surface Wa and reduction of the surface roughness of the first main surface Wa in the first substrate processing apparatus, and then transferred from the first substrate processing apparatus to the second substrate processing apparatus, where the second main surface Wb is ground. The same applies to the first and second modified examples described below.

[0065] Next, a substrate processing method according to a first modification will be described with reference to Fig. 5. The following mainly focuses on the differences from the above embodiment. The substrate processing method of this modification includes step S106 in addition to steps S101 to S104 and S107 to S109.

[0066] Step S106 includes irradiating the second main surface Wb with a third laser beam to reduce the surface roughness Ra of the second main surface Wb. Step S106 preferably includes irradiating the entire second main surface Wb with the third laser beam to uniformize the surface roughness Ra of the second main surface Wb. Step S106 is performed in the same manner as step S103, and is therefore not shown in the drawings.

[0067] According to this modification, by reducing the surface roughness Ra of the second main surface Wb before grinding the second main surface Wb, wear of the grinding wheel can be reduced during grinding of the second main surface Wb. Furthermore, according to this modification, by uniforming the surface roughness Ra of the second main surface Wb before grinding the second main surface Wb, it is possible to uniformize the biting of the grinding wheel during grinding of the second main surface Wb.

[0068] Step S106 may be performed before grinding the second main surface Wb (step S107), for example, before step S101. However, in order to reduce the number of times the substrate W is turned over, step S106 is preferably performed immediately before step S107, and is preferably performed after step S104.

[0069] Next, a substrate processing apparatus 1 according to a first modification will be described with reference to Fig. 6. Differences from the above embodiment will be mainly described below. In the substrate processing apparatus 1 according to this modification, the first processing station 3 includes a third laser processing apparatus 37. The third laser processing apparatus 37 performs step S106.

[0070] After the substrate W is inverted (step S104), the first transport device 32 takes the substrate W out of the inverting device 36 and transports it to the third laser processing device 37. Next, the third laser processing device 37 irradiates the second main surface Wb with a third laser beam to reduce the surface roughness Ra of the second main surface Wb (step S106).

[0071] Thereafter, the first transport device 32 takes the substrate W out of the second laser processing device 35 and transports it to the transition device 56 of the second processing station 5. Subsequently, the second transport device 51 takes the substrate W out of the transition device 56 and transports it to the grinding device 52. Thereafter, grinding of the second main surface Wb is performed (step S107).

[0072] According to this modification, the first laser processing device 34, the second laser processing device 35, and the third laser processing device 37 are separately provided. This allows the reduction of waviness on the first main surface Wa of the first substrate W (step S102), the reduction of the surface roughness Ra of the first main surface Wa of the second substrate W (step S103), and the reduction of the surface roughness Ra of the second main surface Wb of the third substrate W (step S106) to be carried out simultaneously. This allows the number of substrates W processed per unit time to be increased.

[0073] Next, a substrate processing method according to a second modified example will be described with reference to FIG. The following mainly focuses on the differences from the first modified example. The substrate processing method of this modified example includes step S105 in addition to steps S101 to S104 and S106 to S109. Steps S105 and S106 are performed consecutively in this order.

[0074] Step S105 includes, before step S106, irradiating the second main surface Wb with a fourth laser beam to reduce waviness of the second main surface Wb. Step S105 is performed in the same manner as step S102, and is therefore not shown in the drawings. The fourth laser beam is different from the third laser beam. Step S106 removes a smaller amount of material per irradiation than step S105.

[0075] According to this modification, in step S105, the second main surface Wb is roughly processed using the fourth laser beam having a high processing speed (a large amount of removal per irradiation), and then in step S106, the second main surface Wb is precisely processed using the third laser beam having a low processing speed (a small amount of removal per irradiation), thereby making it possible to increase the number of substrates W processed per unit time while maintaining processing precision.

[0076] Step S105 may be performed before reducing the surface roughness Ra of the second main surface Wb (step S106), for example, before step S101. However, step S105 is preferably performed immediately before step S106, and preferably after step S104, in order to reduce the number of times the substrate W is turned over.

[0077] Next, a substrate processing apparatus 1 according to a second modified example will be described with reference to Fig. 8. The following mainly focuses on the differences from the first modified example. In the substrate processing apparatus 1 according to this modified example, the first processing station 3 is provided with a fourth laser processing apparatus 38. The fourth laser processing apparatus 38 performs step S105.

[0078] After the substrate W is inverted (step S104), the first transport device 32 takes the substrate W out of the inverting device 36 and transports it to the fourth laser processing device 38. Next, the fourth laser processing device 38 irradiates the second main surface Wb with a fourth laser beam to reduce waviness of the second main surface Wb (step S105).

[0079] Thereafter, the first transport device 32 takes out the substrate W from the fourth laser processing device 38 and transports it to the third laser processing device 37. Thereafter, the surface roughness Ra of the second main surface Wb is reduced (step S106).

[0080] According to this modification, the first laser processing device 34, the second laser processing device 35, the third laser processing device 37, and the fourth laser processing device 38 are separately provided. This allows the reduction of waviness on the first main surface Wa of the first substrate W (step S102), the reduction of the surface roughness Ra of the first main surface Wa of the second substrate W (step S103), the removal of waviness on the second main surface Wb of the third substrate W (step S105), and the reduction of the surface roughness Ra of the second main surface Wb of the fourth substrate W (step S106) to be performed simultaneously. This allows the number of substrates W processed per unit time to be increased.

[0081] Although the substrate processing method of this modified example includes steps S101 to S109, if the first main surface Wa and the second main surface Wb can be processed to the desired surface accuracy by steps S101 to S106, steps S107 to S109 are unnecessary. If the first main surface Wa can be processed to the desired surface accuracy by laser processing, at least one of the grinding and etching processes performed on the first main surface Wa after laser processing can be omitted. Furthermore, if the second main surface Wb can be processed to the desired surface accuracy by laser processing, at least one of the grinding and etching processes performed on the second main surface Wb after laser processing can be omitted.

[0082] Although the embodiments of the substrate processing method and substrate processing apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0083] This application claims priority based on Japanese Patent Application No. 2022-115685 filed with the Japan Patent Office on July 20, 2022, the entire contents of which are incorporated herein by reference.

[0084] W: Substrate Wa: First main surface Wb: Second main surface LB1: First laser beam LB2: Second laser beam

Claims

1. preparing a substrate having a first main surface and a second main surface facing opposite to the first main surface, the first main surface and the second main surface each having undulations; A conveying device conveys the substrate to a first laser processing device; The first laser processing device irradiates the first main surface with a first laser beam to reduce waviness of the first main surface; After the first laser processing device irradiates the first main surface with the first laser beam, the transport device removes the substrate from the first laser processing device; The transport device transports the substrate removed from the first laser processing device to a second laser processing device; The second laser processing device irradiates the first main surface with a second laser beam different from the first laser beam to reduce a surface roughness of the first main surface; After the second laser processing device irradiates the first main surface with the second laser beam, the transport device removes the substrate from the second laser processing device; The substrate processing method comprises:

2. The substrate processing method according to claim 1 , wherein the first laser beam removes a larger amount of material per irradiation than the second laser beam.

3. 3. The substrate processing method according to claim 1, further comprising: after reducing the surface roughness of the first main surface, grinding the second main surface while the first main surface is attracted to an attraction surface of a chuck.

4. 4. The substrate processing method according to claim 3, further comprising: after grinding the second main surface, grinding the first main surface while the second main surface is being attracted to an attraction surface of a chuck.

5. 4. The substrate processing method according to claim 3, further comprising, prior to grinding the second main surface, irradiating the second main surface with a third laser beam to reduce a surface roughness of the second main surface.

6. 6. The substrate processing method according to claim 5, further comprising irradiating the second main surface with a fourth laser beam different from the third laser beam before reducing the surface roughness of the second main surface, thereby reducing waviness of the second main surface.

7. The substrate processing method according to claim 6 , wherein the fourth laser beam removes a larger amount of material per irradiation than the third laser beam.

8. a transport device configured to transport a substrate having a first main surface and a second main surface facing opposite to the first main surface, the first main surface and the second main surface each having undulations; a first laser processing device that irradiates the first main surface with a first laser beam to reduce waviness of the first main surface; a second laser processing device that irradiates the first main surface with a second laser beam different from the first laser beam after the waviness of the first main surface is reduced by the first laser processing device, thereby reducing a surface roughness of the first main surface; A control device; Equipped with The control device includes: Controlling the transfer device to transfer the substrate to the first laser processing device; Control of the first laser processing device to irradiate the first laser beam onto the first main surface and reduce waviness of the first main surface; a control in which the transport device removes the substrate from the first laser processing device after the first laser processing device irradiates the first main surface with the first laser beam; Controlling the transfer device to transfer the substrate removed from the first laser processing device to the second laser processing device; Control of the second laser processing device to irradiate the first main surface with the second laser beam to reduce surface roughness of the first main surface; control in which the transport device removes the substrate from the second laser processing device after the second laser processing device irradiates the first main surface with the second laser beam; The substrate processing apparatus performs the above steps.

9. The substrate processing apparatus according to claim 8 , wherein the first laser beam removes a larger amount of material per irradiation than the second laser beam.

10. 10 . The substrate processing apparatus according to claim 8 , further comprising: a grinding device configured to reduce a surface roughness of the first main surface, and then grind the second main surface while the first main surface is attracted to an attraction surface of a chuck.

11. The substrate processing apparatus according to claim 10 , wherein the grinding device grinds the first main surface after grinding the second main surface, while the second main surface is held by suction on an attraction surface of a chuck.

12. The substrate processing apparatus according to claim 10 , further comprising a third laser processing apparatus that irradiates the second main surface with a third laser beam before grinding the second main surface, thereby reducing a surface roughness of the second main surface.

13. 13. The substrate processing apparatus according to claim 12, further comprising a fourth laser processing apparatus that irradiates the second main surface with a fourth laser beam different from the third laser beam before reducing the surface roughness of the second main surface, thereby reducing waviness of the second main surface.

14. The substrate processing apparatus according to claim 13 , wherein the fourth laser beam has a larger removal amount per irradiation than the third laser beam.