Substrate processing method and substrate processing apparatus

Abstract

The substrate processing method sequentially includes: preparing a substrate having a first main surface and a second main surface facing the opposite direction of the first main surface, and having undulations on the first main surface and the second main surface; performing laser processing on the first main surface; grinding or grinding the second main surface; and grinding or grinding the first main surface. The substrate processing method comprises the following steps: acquiring mapping data of fluctuation of the first main surface before laser processing; and mapping data of the undulation of the first main surface, which is acquired before the laser processing of this time, in addition to mapping data of the undulation of the first main surface, further, processing conditions for this laser processing are set on the basis of desired data of the substrate after the laser processing of the first main surface, the grinding or polishing of the second main surface, and the grinding or polishing of the first main surface have been sequentially performed in the past.

Description

TECHNICAL FIELD

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

[0002] A method for processing a semiconductor wafer is described in Patent Literature 1. In the method for processing, a semiconductor wafer obtained by slicing a single crystal ingot is subjected to a chamfering process, a polishing process, an etching process, and a mirror polishing process.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2002-203823 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] One embodiment of the present disclosure provides a technique for improving flatness of a substrate.

[0008] SOLUTION TO PROBLEM

[0009] A substrate processing method according to one embodiment of the present disclosure sequentially includes: preparing a substrate having a first main surface and a second main surface facing in an opposite direction to the first main surface, and having undulations on the first main surface and the second main surface, respectively; performing laser processing of the first main surface; performing grinding processing or polishing processing of the second main surface; and performing grinding processing or polishing processing of the first main surface. The substrate processing method includes: acquiring mapping data of the undulations of the first main surface before the laser processing; and setting processing conditions of the laser processing of this time based on desired data of the substrate after the laser processing of the first main surface, the grinding processing or polishing processing of the second main surface, and the grinding processing or polishing processing of the first main surface have been sequentially performed in the past, in addition to the mapping data of the undulations of the first main surface acquired before the laser processing of this time.

[0010] EFFECT OF THE INVENTION

[0011] According to one embodiment of the present disclosure, flatness of a substrate can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a flowchart illustrating a substrate processing method according to one embodiment.

[0013] Figure 2 is a cross-sectional view illustrating an example of step S101.

[0014] Figure 3is a cross-sectional view showing an example of step S103.

[0015] Figure 4 is a cross-sectional view showing an example of step S104.

[0016] Figure 5 is a cross-sectional view showing an example of step S106.

[0017] Figure 6 (A) of FIG. 10 is a cross-sectional view showing an example of step S108, Figure 6 (B) of FIG. 10 is a cross-sectional view showing an example of step S110.

[0018] Figure 7 is a plan view showing a substrate processing apparatus according to an embodiment.

[0019] Figure 8 is a view showing an example of a configuration element of a control circuit by functional blocks.

[0020] Figure 9 is a plan view showing an example of movement of an irradiation point in a processing region.

[0021] Figure 10 is a cross-sectional view showing an example of a recessed portion.

[0022] Figure 11 is a plan view showing a modification example of movement of an irradiation point in a processing region.

[0023] Figure 12 is a view showing an example of a power density of an irradiation point.

[0024] Figure 13 (A) of FIG. 12 is a view showing an example of mapping data of a relief of a first main surface acquired before laser processing, Figure 13 (B) of FIG. 12 is a view showing an example of mapping data of a processing amount in laser processing, Figure 13 (C) of FIG. 12 is a view showing an example of mapping data of a relief of a first main surface acquired after grinding processing. DETAILED DESCRIPTION

[0025] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the same or corresponding portions will be denoted by the same reference signs in different drawings, and description thereof will not be repeated. In the drawings used in the following description, Figure 5 , Figure 7 , Figure 9 and Figure 11 , the X-axis direction, the Y-axis direction, and the Z-axis direction are directions perpendicular to one another, the X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is a vertical direction.

[0026] Reference will be made to Figures 1-6A substrate processing method relating to one embodiment will be described. For example, as shown in Figure 1 , the substrate processing method has steps S101 to S110. Steps S101 to S110 are performed under the control of a control circuit. Instead of grinding processing, polishing processing can be performed.

[0027] Further, the substrate processing method can not have all steps S101 to S110 shown in Figure 1 . For example, a plurality of substrates constituting the same substrate group have a high possibility of having the same or similar unevenness, and thus S102 to S105 can be performed on one substrate. The processing conditions of one substrate can be used as the laser processing conditions of the remaining substrates. A plurality of (for example, 25) substrates constituting the same substrate group are cut out from a single crystal ingot at the same time and housed in the same cassette.

[0028] In addition, the substrate processing method can further have a step not shown in the drawing. As the step not shown in the drawing, for example, cleaning or etching of the substrate is cited. The cleaning or etching of the substrate is performed, for example, immediately after the laser processing (step S106) or immediately after the grinding processing (step S108 or S110). Both the cleaning and the etching can be performed.

[0029] The etching of the substrate can be performed before the acquisition of the mapping data of the unevenness (step S102). By removing a damage layer generated at the time of cutting of the single crystal ingot by etching, it is possible to improve the measurement accuracy of the mapping data of the unevenness. In addition, since the damage layer does not become a problem, it is also possible to accelerate the cutting speed.

[0030] Next, the processing after step S101 will be described. Step S101 includes preparing a substrate W (refer to Figure 2 ). The preparation of the substrate W includes, for example, carrying the substrate W into the substrate processing apparatus 1 described later. The substrate W is carried into the substrate processing apparatus 1 in a state of being housed in the cassette C.

[0031] The substrate W is a silicon wafer or a compound semiconductor wafer. The compound semiconductor wafer is not particularly limited, but is, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer. The substrate W is a bare wafer. The substrate W is, for example, a disc shape. The substrate W can have a bevel at the periphery thereof.

[0032] As shown in Figure 2 , the substrate W includes a first main surface Wa and a second main surface Wb facing in a direction opposite to the direction of the first main surface Wa. The substrate W has unevenness on the first main surface Wa and the second main surface Wb, respectively. The unevenness has a tendency to have a shape that is linearly symmetrical about a reference line L0 extending in the cutting direction, as shown in (A) of Figure 13 . Figure 13 In (A) of Figure 13 , the height of the mapping data is represented by the gradation. The color is closer to white from black, and the height is higher.

[0033] The undulations of the first principal surface Wa and the second principal surface Wb are pre-measured by an undulation measuring device. The undulation measuring device can be either contact or non-contact. A commercially available three-dimensional measuring machine is used, such as the SBW-330 manufactured by Kobe Steel Research Co., Ltd. The undulation is represented by the height from the reference plane. The reference plane is a plane. The reference plane can be, for example, a plane obtained by approximating the center planes of the first principal surface Wa and the second principal surface Wb using the least squares method, but it can also be a crystal plane represented by the desired Miller indices, or a plane tilted only by the desired deviation angle relative to that crystal plane.

[0034] Step S102 includes acquiring mapping data of the undulations of the first master surface Wa. The mapping data can be acquired from both the upper and lower surfaces of the substrate W, or the surface with the smaller difference in undulation height can be designated as the first master surface Wa. The first master surface Wa simply needs to be the surface to be laser-processed.

[0035] Step S103 includes mapping data based on the fluctuations obtained in step S102, such as... Figure 3 Create the mapping data for the processing quantity D as shown. Figure 3 In the diagram, dashed lines represent contour lines. The processing amount D is mainly determined by the height from the reference point P0 in the undulating mapping data. The height of the reference point P0 is the height of the first master surface Wa obtained through laser processing. The reference point P0 can be either the lowest point in the undulating mapping data or a point shifted downwards by a set amount from that lowest point.

[0036] In addition, the mapping data for the processing volume D can also be created using a model generated through machine learning, but details will be discussed later.

[0037] Step S104 includes, for example, Figure 4 As shown, the mapping data of the processing amount D created in step S103 is divided according to the height to create n (e.g., 3) layers L1, L2, L3. n can be any integer greater than 2, and is not limited to 3.

[0038] n is set based on the maximum processing amount D, Dmax, and the processing amount per laser irradiation. The processing amount per irradiation is determined by the power density of the irradiation point P. Alternatively, n can be set based on the upper limit of the surface roughness after laser processing.

[0039] In this embodiment, the n layers L1, L2, and L3 have the same thickness, but they can also have different thicknesses. The thickness of each of the n layers L1, L2, and L3 is appropriately set according to the power density of the irradiation point P and the overlap of the trajectories of adjacent irradiation points P, but for example, it is 0.1 μm to 1.0 μm.

[0040] Step S105 includes setting a processing region for each of the layers L1, L2, L3 made in step S104. As for the processing region of each of the layers L1, L2, L3, the processing region of each of the layers L1, L2, L3 is respectively identical in the present embodiment, but can be different. For example, in Figure 4 , the processing region of the layer L3 as the lowermost layer can also be expanded in a manner connecting the two layers L3 apart.

[0041] As shown in Figure 5 , step S106 includes performing laser processing of the first main surface Wa. The laser processing is ablation processing. At the irradiation point P of the laser light LB, the substrate W is locally changed from a solid phase to a gas phase and scattered, or scattered in a solid phase, so that the substrate W is locally cut. Further, details of the laser processing device 35 are described later.

[0042] Step S106 includes, for example, moving the irradiation point P of the laser light LB in the processing region for each of the layers L1, L2, L3. The n layers L1, L2, L3 are removed in a desired order. For example, a layer (for example, the layer L1) having a high height is removed earlier than a layer (for example, the layer L2) having a low height.

[0043] Step S106 includes moving the irradiation point P in the entire processing region of the (k+1)th removed layer after moving the irradiation point P in the entire processing region of the kth removed layer. k is an integer of 1 or more and (n-1) or less. Thereby, the layers L1, L2, L3 are removed for each of the layers L1, L2, L3.

[0044] According to the present embodiment, the irradiation point P is moved in the processing region for each of the layers L1, L2, L3. The n layers L1, L2, L3 can be removed in a desired order. The layers L1, L2, L3 each have a certain thickness, so that the power density of the irradiation point P can not be changed and the output of the light source can not be changed in most of the respective processing regions. Therefore, the control of the laser processing can be simplified.

[0045] As described above, the n layers L1, L2, L3 can also have the same thickness. The power density of the irradiation point P can not be changed and the output of the light source can not be changed for each of the layers L1, L2, L3. Therefore, the control of the laser processing can be further simplified. However, two or more of the n layers L1, L2, L3 can also have different thicknesses in consideration of the gradient of the relief and the like.

[0046] Further, in the present embodiment, the irradiation point P is moved in the processing region for each layer L1, L2, L3, but the technology of the present disclosure is not limited thereto. If the power density of the irradiation point P is changed each time according to the position of the irradiation point P while referring to the height of the mapping data of the processing amount D, the mapping data of the processing amount D can also not be divided into n layers.

[0047] Step S107 includes turning over the substrate W. Step S107 includes turning over the substrate W upside down to make the first main surface Wa of the substrate W face downward and the second main surface Wb of the substrate W face upward.

[0048] As shown in (A) of FIG. 10, step S108 includes performing grinding processing of the second main surface Wb in a state where the first main surface Wa that is planarized by laser processing is adsorbed by the adsorption surface 391a of the holding disc 391. The processing tool 392 includes, for example, a grindstone. By grinding the second main surface Wb in parallel with the first main surface Wa that is planarized in advance, the second main surface Wb can be planarized. Further, instead of grinding processing, polishing processing can also be performed. Figure 6

[0049] It is assumed that when the adsorption surface 391a of the holding disc 391 adsorbs the first main surface Wa in a state where the first main surface Wa has undulations, the first main surface Wa is planarized along the adsorption surface 391a. In this state, when the adsorption of the substrate W is released after grinding the second main surface Wb in parallel with the first main surface Wa, not only the first main surface Wa returns to a state of having undulations, but also the same undulations as the first main surface Wa are generated in the second main surface Wb.

[0050] According to the present embodiment, by grinding the second main surface Wb in parallel with the first main surface Wa that is planarized in advance by laser processing, the second main surface Wb can be planarized. In addition, compared to a case where both surfaces of the substrate W are planarized by laser light, it is possible to remove undulations existing in both surfaces of the substrate W in a short time. This is because laser processing is slower in processing speed compared to grinding processing.

[0051] Step S109 includes turning over the substrate W. Step S109 includes turning over the substrate W upside down to make the first main surface Wa of the substrate W face upward and the second main surface Wb of the substrate W face downward.

[0052] As shown in (A) of FIG. 10, step S108 includes performing grinding processing of the second main surface Wb in a state where the first main surface Wa that is planarized by laser processing is adsorbed by the adsorption surface 391a of the holding disc 391. The processing tool 392 includes, for example, a grindstone. By grinding the second main surface Wb in parallel with the first main surface Wa that is planarized in advance, the second main surface Wb can be planarized. Further, instead of grinding processing, polishing processing can also be performed. Figure 6 ​As shown in (B), step S110 includes grinding the first main surface Wa while the second main surface Wb, which has been planarized by grinding, is adsorbed on the adsorption surface 391a of the holding disk 391. This allows the processing quality of the first main surface Wa and the second main surface Wb to be equivalent. Since the first main surface Wa has been planarized by laser processing, the grinding amount of the first main surface Wa can also be less than that of the second main surface Wb. Alternatively, lapping can be performed instead of grinding.

[0053] Next, refer to Figure 7 This section describes a substrate processing apparatus 1 according to one embodiment. The substrate processing apparatus 1 performs... Figure 1 Steps S101 to S107 are shown. Steps S108 to S110 are performed outside of the substrate processing apparatus 1. Furthermore, the substrate processing apparatus 1 may also include... Figure 6 (A) and Figure 6 The grinding apparatus 39 shown in (B) can also be used to perform steps S108 to S110. Alternatively, a polishing apparatus can be provided instead of the grinding apparatus 39.

[0054] The substrate processing apparatus 1 includes a loading / unloading station 2, a processing station 3, and a control circuit 9. The loading / unloading station 2 and the processing station 3 are arranged from the negative side of the X-axis direction to the positive side of the X-axis direction in the order of loading / unloading station 2 and processing station 3.

[0055] The loading / unloading station 2 includes a loading platform 20, a second transport area 21, and a second transport device 22. Multiple boxes C are loaded on the loading platform 20. Each box C contains multiple substrates W. Multiple substrates W cut from a single crystal ingot are simultaneously housed in the same box C. The number of boxes C is not specifically limited.

[0056] The second transport area 21 is adjacent to the conveying device 33 of the loading platform 20, i.e., the processing station 3. The second transport device 22 transports substrates between multiple devices adjacent to the second transport area 21. The second transport device 22 has a transport arm that holds the substrate W and a drive unit that moves or rotates the transport arm. The transport arm is capable of moving in the horizontal direction (both the X-axis and Y-axis directions) and the vertical direction, as well as rotating about the vertical axis. Multiple transport arms may also be provided.

[0057] Processing station 3 includes a first conveying area 31, a first conveying device 32, a conveying device 33, an undulation measuring device 34, a laser processing device 35, a cleaning device 36, a flipping device 37, and an alignment device 38. Furthermore, the configuration and number of the devices constituting processing station 3 are not limited to… Figure 7 The configuration and quantity are shown.

[0058] The first transfer region 31 is adjacent to the transfer device 33, the fluctuation measuring device 34, the laser processing device 35, the cleaning device 36, the turnover device 37, and the alignment device 38. The first transfer device 32 transfers the substrate between the plurality of devices adjacent to the first transfer region 31. The first transfer device 32 has a transfer arm that holds the substrate W and a driving portion that moves or rotates the transfer arm. The transfer arm is capable of movement in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction and rotation about the vertical axis. A plurality of transfer arms can also be provided.

[0059] The transfer device 33 relays the substrate W between the second transfer device 22 of the in-out station 2 and the first transfer device 32 of the processing station 3. A transfer device 33 for relaying from the second transfer device 22 to the first transfer device 32 and a transfer device 33 for relaying from the first transfer device 32 to the second transfer device 22 can also be provided separately.

[0060] The fluctuation measuring device 34 measures the fluctuation of the first main surface Wa of the substrate W. The fluctuation measuring device 34 can also measure the fluctuation of the second main surface Wb of the substrate W. The fluctuation measuring device 34 transmits the measurement data to the control circuit 9. The control circuit 9 acquires the map data of the fluctuation of the first main surface Wa from the fluctuation measuring device 34. Furthermore, the fluctuation measuring device 34 is provided inside the substrate processing device 1 in the present embodiment, but can also be provided outside the substrate processing device 1.

[0061] The fluctuation measuring device 34 measures the fluctuation of the first main surface Wa of the substrate W before laser processing in the present embodiment, but can also measure the fluctuation of the first main surface Wa of the substrate W after laser processing. In addition, the fluctuation measuring device 34 can also measure the fluctuation of the first main surface Wa of the substrate W after grinding processing or polishing processing.

[0062] The laser processing device 35 performs laser processing of the first main surface Wa of the substrate W. The laser processing device 35, for example, moves the irradiation point P in the processing region for each layer L1, L2, L3. The n layers L1, L2, L3 can be removed in the desired order. By performing laser processing of the first main surface Wa, the fluctuation of the first main surface Wa can be reduced.

[0063] The turnover device 37 turns the substrate W upside down. The turnover device 37 can also relay the substrate W between the first transfer device 32 and the second transfer device 22 as with the transfer device 33. The turnover device 37 and the transfer device 33 can also be stacked in the vertical direction.

[0064] The alignment device 38 detects the notch of the substrate W while rotating the substrate W, thereby orienting the notch of the substrate W in the desired direction. The notch indicates the crystal orientation of the substrate W. The alignment device 38 can also detect an orientation flat instead of the notch.

[0065] The control circuit 9 is, for example, a computer, including 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 circuit 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. Alternatively, a lower-level control circuit can be provided for each device constituting the substrate processing apparatus 1 to control the operation of the device, and a higher-level control circuit can be provided to uniformly control multiple lower-level control circuits. The control circuit 9 can be composed of lower-level control circuits and a higher-level control circuit.

[0066] The control circuit 9 includes electronic circuits such as a CPU, FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit), and executes various control actions described in this application specification by executing command codes stored in memory or by designing circuits for special purposes.

[0067] like Figure 8 As shown, the control circuit 9 includes, for example, a data acquisition unit 901, a processing amount setting unit 902, a layer fabrication unit 903, a processing area setting unit 904, a movement control unit 905, a power density control unit 906, and a model generation unit 907. The data acquisition unit 901 acquires mapping data of the undulations of the first main surface Wa of the substrate W. The processing amount setting unit 902 creates mapping data for the processing amount D in laser processing based on the undulation mapping data acquired by the data acquisition unit 901. The layer fabrication unit 903 creates n layers L1, L2, L3 by dividing the mapping data of the processing amount D created by the processing amount setting unit 902 according to the height. The processing area setting unit 904 sets a processing area for each layer L1, L2, L3 created by the layer fabrication unit 903. The movement control unit 905 controls the movement of the irradiation point P within the processing area for each layer L1, L2, L3. The power density control unit 906 sets the power density (unit: W / cm²) of the irradiation point P. 2 The model generation unit 907 generates the model used in the creation of the mapping data for the processing quantity D, but details will be described later.

[0068] also, Figure 8The illustrated functional blocks are conceptual, and need not necessarily be physically configured as illustrated. All or a portion of the functional blocks can be dispersed / centralized in any unit in terms of function or physicality. All or any portion of the processing functions performed by the functional blocks can be realized by a program executed by a CPU or as hardware based on wiring logic.

[0069] Next, the operation of the substrate processing apparatus 1 having the above-described configuration will be described. First, an unillustrated conveyance apparatus conveys the substrate W into the substrate processing apparatus 1. Thus, preparation of the substrate W is performed (step S101). The substrate W is placed on the placement table 20 in a state of being housed in the cassette C. Next, the second conveyance apparatus 22 takes out the substrate W from the cassette C on the placement table 20 and conveys it to the transfer apparatus 33. Next, the first conveyance apparatus 32 of the processing station 3 takes out the substrate W from the transfer apparatus 33 and conveys it to the alignment apparatus 38.

[0070] Next, the alignment apparatus 38 detects the notch of the substrate W while rotating the substrate W, thereby orienting the notch of the substrate W in a desired direction. Thereafter, the first conveyance apparatus 32 takes out the substrate W from the alignment apparatus 38 and conveys it to the fluctuation measuring apparatus 34.

[0071] Next, the fluctuation measuring apparatus 34 measures the fluctuation of the first main surface Wa of the substrate W. The fluctuation measuring apparatus 34 transmits the measurement data to the control circuit 9. The data acquisition section 901 acquires the map data of the fluctuation of the first main surface Wa (step S102). Next, the processing amount setting section 902 creates map data of the processing amount D in laser processing based on the map data of the fluctuation (step S103). Next, the layer creation section 903 creates the n layers L1, L2, L3 by dividing the map data of the processing amount D according to the height (step S104). Next, the processing region setting section 904 sets the processing region for each of the layers L1, L2, L3 (step S105).

[0072] Next, the first conveyance apparatus 32 takes out the substrate W from the fluctuation measuring apparatus 34 and conveys it to the laser processing apparatus 35. Further, steps S102 to S105 can be performed as long as they are performed before the start of the laser processing of the first main surface Wa (step S106). Steps S102 to S105 can also be performed after the first conveyance apparatus 32 takes out the substrate W from the fluctuation measuring apparatus 34.

[0073] Next, the laser processing apparatus 35 performs laser processing of the first main surface Wa (step S106). The movement control section 905 controls the movement of the irradiation point P in the processing region for each of the layers L1, L2, L3. After the laser processing of the first main surface Wa, the first conveyance apparatus 32 takes out the substrate W from the laser processing apparatus 35 and conveys it to the cleaning apparatus 36.

[0074] Next, the cleaning device 36 cleans the first main surface Wa of the substrate W. After that, the first conveyance device 32 takes out the substrate W from the cleaning device 36 and conveys it to the turnover device 37. Next, the turnover device 37 turns upside down the substrate W (step S107). Next, the second conveyance device 22 takes out the substrate W from the turnover device 37 and accommodates it in the cassette C on the stage 20. Finally, a conveyance device not shown takes out the substrate W from the substrate processing device 1 in the state of being accommodated in the cassette C.

[0075] Next, the cleaning device 36 cleans the first main surface Wa of the substrate W. After that, the first conveyance device 32 takes out the substrate W from the cleaning device 36 and conveys it to the turnover device 37. Next, the turnover device 37 turns upside down the substrate W (step S107). Next, the second conveyance device 22 takes out the substrate W from the turnover device 37 and accommodates it in the cassette C on the stage 20. Finally, a conveyance device not shown takes out the substrate W from the substrate processing device 1 in the state of being accommodated in the cassette C. Figure 5 An example of the laser processing device 35 will be described. The laser processing device 35 is provided with a substrate holding section 351, a light source 352, and an electric probe scanner 353. In addition, the laser processing device 35 can have a fθ lens 354, a homogenizer 355, and an aperture 356.

[0076] The substrate holding section 351 holds the substrate W. For example, the substrate holding section 351 holds the substrate W horizontally from below with the first main surface Wa of the substrate W facing upward. The substrate holding section 351 does not adsorb the substrate W and holds the substrate W in a natural state in which no external force other than gravity and its resistance acts. Alternatively, the substrate holding section 351 can adsorb the substrate W. The substrate holding section 351 can be a vacuum holding plate or an electrostatic holding plate.

[0077] The light source 352 oscillates a laser beam LB. In the case where the substrate W is a silicon wafer, the laser beam LB is, for example, UV light. At an irradiation point P of the laser beam LB, the substrate W locally changes from a solid phase to a gas phase and scatters or scatters in a solid phase, and the substrate W is locally cut. The laser beam LB can be condensed and irradiated on the upper surface of the substrate W. The irradiation point P is a condensing point at which the power density is highest in the present embodiment, but can not be a condensing point.

[0078] The light source 352 is, for example, a pulse laser. The irradiation time of each pulse is, for example, 30 nsec or less. If the irradiation time of each pulse is 30 nsec or less, the substrate W can be irradiated with a high power density laser beam LB in a short time, and overheating of the substrate W can be suppressed. Thus, deterioration of the substrate W due to heat, for example, generation of a discoloration layer, can be suppressed. The irradiation time of each pulse is preferably 10 psec or less. If the irradiation time of each pulse is 10 psec or less, even if the irradiation point P is formed multiple times at the same site, deterioration of the substrate W due to heat can be suppressed.

[0079] The current detector 353 is disposed, for example, above the substrate W held by the substrate holder 351. According to the current detector 353, the irradiation point P of the laser beam LB can be moved on the upper surface of the substrate W without moving the substrate holder 351. Even when the substrate holder 351 does not hold the substrate W, as long as the substrate holder 351 does not move, there will be no positional shift of the substrate W relative to the substrate holder 351. Therefore, the position of the irradiation point P can be controlled with high precision.

[0080] The current detector 353 includes two sets (in) Figure 5 (Only one set is illustrated) An electroscope 357 and an electroscope motor 358 are assembled. One electroscope motor 358 rotates one electroscope 357 to shift the illumination point P in the X-axis direction. Another electroscope motor 358 rotates another electroscope 357 to shift the illumination point P in the Y-axis direction.

[0081] The electro-detector scanner 353 is an example of a moving part that moves the irradiation point P. Furthermore, the moving part can move the substrate holding part 351 in the X-axis and Y-axis directions, and may also have a motor and a ball screw mechanism that converts the rotational motion of the motor into the linear motion of the substrate holding part 351. Additionally, the moving part may also have a mechanism that rotates the substrate holding part 351 about a vertical axis.

[0082] The fθ lens 354 forms a focal plane perpendicular to the Z-axis direction. During the movement of the illumination point P in the X-axis or Y-axis direction by the detector 353, the fθ lens 354 maintains the shape and size of the illumination point P on the upper surface of the substrate W. In this embodiment, the height of the illumination point P is the same as the height of the focal plane, but it may not be the same as the height of the focal plane, and it may be higher or lower than the height of the focal plane.

[0083] The homogenizer 355 converts the power density distribution of the laser beam LB from a Gaussian distribution to a flat-top distribution, thus homogenizing the power density. The aperture 356 shapes the cross-sectional shape of the laser beam LB into a rectangle. The aperture 356 is a light-shielding film with a rectangular opening. This opening allows the portion of the laser beam LB with a fixed power density to pass through. Using the homogenizer 355 and the aperture 356, a rectangular illumination point P with uniform power density can be formed.

[0084] Next, refer to Figure 9 An example of the movement of the irradiation point P in processing area A will be illustrated. Figure 9 In the diagram, the arrow indicates the direction and range of movement of the irradiated point P. The range of movement is the distance from the starting point to the ending point of the movement. (This will be discussed later.) Figure 11 In the image, the arrows represent the same thing. Furthermore, the movement of the irradiation point P is not limited to... Figure 9 and Figure 11The movement of the irradiation point P can also be performed spirally, for example.

[0085] For example as Figure 9 As illustrated, the movement control section 905 repeatedly performs control to move the irradiation point P in a first direction (for example, the positive direction of the X axis) and control to move the irradiation point P in a second direction (for example, the negative direction of the X axis) opposite to the first direction. In addition, the movement control section 905 performs control to displace the position of the irradiation point P in a third direction (for example, the negative direction of the Y axis) perpendicular to the first direction and the second direction before and after changing the moving direction of the irradiation point P between the first direction and the second direction.

[0086] The first trajectory in which the irradiation points P adjacent in the third direction move in the first direction and the second trajectory in which the irradiation points P move in the second direction can also partially overlap in the third direction. The pitch of the irradiation points P in the third direction can also be smaller than the size of the irradiation points P in the third direction, so that the first trajectory and the second trajectory partially overlap in the third direction. By providing the first trajectory and the second trajectory with overlap in the third direction, it is possible to make the processing trace formed along the moving direction of the irradiation point P (the first direction or the second direction) thin.

[0087] The movement control section 905 can also perform control to change the moving direction of the irradiation point P to be perpendicular or inclined between the kth removed layer and the (k+1)th removed layer. For example, the movement control section 905 can also perform control to change the moving direction of the irradiation point P to be perpendicular or inclined between the odd-numbered removed layers and the even-numbered removed layers.

[0088] For example, the movement control section 905 repeatedly performs control to move the irradiation point P in the first direction and control to move the irradiation point P in the second direction when removing the odd-numbered layers L1, L3. In addition, the movement control section 905 performs control to displace the position of the irradiation point P in the third direction before and after changing the moving direction of the irradiation point P between the first direction and the second direction when removing the odd-numbered layers L1, L3.

[0089] On the other hand, the movement control section 905 repeatedly performs control to move the irradiation point P in the third direction and control to move the irradiation point P in a fourth direction (for example, the positive direction of the Y axis) opposite to the third direction when removing the even-numbered layers L2. In addition, the movement control section 905 performs control to displace the position of the irradiation point P in the first direction or the second direction before and after changing the moving direction of the irradiation point P between the third direction and the fourth direction when removing the even-numbered layers L2.

[0090] As described above, the movement control section 905 performs control to change the moving direction of the irradiation point to be perpendicular or inclined (perpendicular in this embodiment) between the kth removed layer and the (k+1)th removed layer. Thereby, it is possible to make the processing trace formed along the moving direction of the irradiation point P thin. Therefore, it is possible to reduce the surface roughness of the first main surface Wa after laser processing.

[0091] In addition, the processing region A is set for each layer L1, L2, L3. The periphery of the processing region A coincides with the periphery of each of the layers L1, L2, L3. The start point at which the movement of the irradiation point P is started and the end point at which the movement of the irradiation point P is ended are set to the periphery of the processing region A, for example, as shown in Figure 9

[0092] The inventors of the present application found that, in the case where the start point and the end point are set to the periphery of the processing region A as shown in Figure 9 Figure 10

[0093] Further, when the second main surface Wb is ground in parallel with the first main surface Wa after the recess Wc is formed in the state where the first main surface Wa is ground, a local recess is formed in the second main surface Wb, like the first main surface Wa.

[0094] Therefore, as shown in Figure 11 Figure 11 Therefore, as shown in

[0095] In the present embodiment, the movement control section 905 displaces the positions of both the start point and the end point from the periphery of the processing region A when moving the irradiation point P in the first direction and when moving the irradiation point P in the second direction, but the technology of the present disclosure is not limited thereto. As long as the start point and the end point are arranged in a zigzag manner along the periphery of the processing region A, that is, in a manner in which the periphery is repeatedly approached and distanced from the periphery along the periphery of the processing region A.

[0096] ​​​​For example, the movement control unit 905 may, when moving the irradiation point P in the first direction, shift the positions of both the start point and the end point from the periphery of the processing area A, and when moving the irradiation point P in the second direction, prevent the start point and the irradiation point from shifting from the periphery of the processing area A. Alternatively, the movement control unit 905 may, when moving the irradiation point P in the first direction and when moving the irradiation point P in the second direction, shift only the position of the start point from the periphery of the processing area A, or shift only the position of the end point from the periphery of the processing area A.

[0097] As described above, the start and end points can be configured in a serrated pattern along the periphery of the processing area A, that is, by repeatedly approaching and moving away from the periphery along the periphery of the processing area A. This suppresses the formation of the recess Wc. This effect is particularly pronounced when the first and second trajectories, which are adjacent in the third direction, partially overlap in the third direction.

[0098] When a first trajectory and a second trajectory that are adjacent in the third direction partially overlap in the third direction, the start point of the first trajectory and the end point of the second trajectory are separated in a non-overlapping manner. Similarly, when a first trajectory and a second trajectory that are adjacent in the third direction partially overlap in the third direction, the end point of the first trajectory and the start point of the second trajectory are separated in a non-overlapping manner. This suppresses the formation of the concave portion Wc.

[0099] Or, such as Figure 12 As shown, the power density control unit 906 can also control the power density of the irradiation point P at the periphery of the processing area A to decrease compared to the power density of the irradiation point P at the center of the processing area A. The amount of power density decrease ΔW is preset through experiments, etc. The power density of the irradiation point P is controlled, for example, by the output of the light source 352. By decreasing the power density of the irradiation point P at the periphery of the processing area A compared to the power density of the irradiation point P at the center of the processing area A, the formation of a local concave portion Wc along the periphery of the processing area A can be suppressed, thereby improving the processing quality of the laser processing.

[0100] also, Figure 11 The control and Figure 12 The controls shown can also be used in combination. Additionally, Figure 11 The control and shown Figure 12 The control shown can also be applied to cases where the mapping data of the processing amount D is not divided into n layers L1, L2, L3. In this case, it is also possible to suppress the formation of localized recesses Wc along the periphery of the processing area A, thereby improving the processing quality of laser processing.

[0101] Next, refer to Figure 13 For example Figure 1An example of three mapping data of the substrate W after the laser processing of the first main surface Wa, the grinding processing of the second main surface Wb, and the grinding processing of the first main surface Wa2 have been sequentially performed as illustrated will be described. Figure 13 (A) is mapping data of the undulation of the first main surface Wa acquired before the laser processing. Figure 13 (B) is mapping data of the processing amount D in the laser processing. Figure 13 (C) is mapping data of the undulation of the first main surface Wa acquired after the grinding processing. In Figure 13 In (C), the height of the mapping data is represented by the gradation. The color is closer to white as the color is closer to black, and the height is higher.

[0102] The inventors of the present application found that after the laser processing of the first main surface Wa is performed in such a manner that the undulation of the first main surface Wa is completely removed by the laser processing and the mapping data of the processing amount D is made and the laser processing of the first main surface Wa is performed according to the mapping data, the undulation of the first main surface Wa is not completely removed but remains after the grinding processing. It can be considered that unexpected deformation of the substrate W is generated in the laser processing or the grinding processing. In addition, as described above, polishing processing can be performed instead of the grinding processing.

[0103] Therefore, the processing amount setting section 902 can make the mapping data of the processing amount D in the laser processing of this time based on not only the mapping data of the undulation of the first main surface Wa acquired before the laser processing of this time but also expected data of the substrate W after the laser processing of the first main surface Wa, the grinding processing or the polishing processing of the second main surface Wb, and the grinding processing or the polishing processing of the first main surface Wa have been sequentially performed in the past.

[0104] The expected data, for example, includes (A) mapping data of the undulation of the first main surface Wa acquired before the laser processing, (B) mapping data of the processing amount D in the laser processing, and (C) data of the undulation of the first main surface Wa acquired after the grinding processing or the polishing processing.

[0105] (C) is data of the undulation of the first main surface Wa acquired after the grinding processing or the polishing processing. In the present embodiment, the data is mapping data, but can be simply data of the height difference. The height difference of the undulation after the grinding processing or the polishing processing is used as scoring data of the mapping data of the processing amount. The smaller the height difference of the undulation after the grinding processing or the polishing processing is, the better the score is.

[0106] According to the present embodiment, not only the mapping data of the undulation of the first main surface Wa acquired before the laser processing of this time but also the expected data are used, whereby the mapping data of the processing amount D in the laser processing of this time can be appropriately corrected. As a result, the height difference of the undulation of the first main surface Wa acquired after the grinding processing or the polishing processing of this time can be reduced.

[0107] For example, a regression analysis or the like is performed to absorb errors caused by unexpected deformation that is considered to have occurred in past laser processing, grinding processing, or polishing processing, and the mapping data of the processing amount D in this time's laser processing can be corrected. By feeding back the past data into the processing conditions of this time, the flatness of the substrate W can be improved.

[0108] The processing amount setting section 902 can also output the mapping data of the processing amount D in this time's laser processing by inputting the mapping data of the undulation of the first main surface Wa acquired before this time's laser processing to a model that is a model obtained by machine learning using the desired data as training data, so that the difference in height of the undulation after this time's grinding processing or polishing processing becomes equal to or less than the set value. By using a model obtained by machine learning in advance, the mapping data of the processing amount D can be appropriately corrected regardless of the proficiency of the user, that is, without depending on the experience and intuition of the user.

[0109] The data input to the model obtained by machine learning can include, in addition to (D) the mapping data of the undulation of the first main surface Wa acquired before this time's laser processing, (E) the mapping data of the predetermined undulation of the first main surface Wa acquired after this time's grinding processing or polishing processing. The data input to the above-described model can also include (F) the difference in height of the predetermined undulation of the first main surface Wa acquired after this time's grinding processing or polishing processing instead of (E).

[0110] The model can be read out and used as it is stored in advance in the storage section, but can also be generated by the model generation section 907. The model generation section 907 generates the model by supervised learning using a known machine learning algorithm such as a convolutional neural network (CNN) using the desired data as training data.

[0111] Further, the processing amount setting section 902 is an example of a processing condition setting section. The processing condition setting section sets the laser processing conditions of this time based on the desired data acquired in the past in addition to the mapping data of the undulation of the first main surface Wa acquired before this time's laser processing. The laser processing conditions can also include, for example, the mapping data of the processing amount D, the number of layers L1, L2, L3, the thickness of each of the layers L1, L2, L3, Figure 11 the ΔL illustrated above, and Figure 12 at least one selected from the ΔW illustrated above.

[0112] The above describes an embodiment of a substrate processing method and a substrate processing apparatus according to the present disclosure, but the present disclosure is not limited to the above-described embodiment. Various modifications, corrections, substitutions, additions, deletions, and combinations can be made within the scope recited in the claims. These are of course within the technical scope of the present disclosure.

[0113] This application claims priority based on Japanese Patent Application No. 2023-062838 filed on April 7, 2023, with the Japan Patent Office, and the entire contents of Japanese Patent Application No. 2023-062838 are hereby incorporated by reference into this application.

[0114] Explanation of Reference Numerals

[0115] LB: laser light; P: irradiation point; W: substrate; Wa: first main surface; Wb: second main surface.

Claims

1. A substrate processing method comprising, in sequence, a process of preparing a substrate having a first main surface and a second main surface facing in a direction opposite to that of the first main surface, and having a relief on each of the first main surface and the second main surface, a process of performing laser processing of the first main surface, a process of performing grinding processing or polishing processing of the second main surface, and a process of performing grinding processing or polishing processing of the first main surface, wherein The substrate processing method includes the following processes: acquiring mapping data of the unevenness of the first main surface before laser processing; and The processing conditions of the present laser processing are set based on the desired data of the substrate after the laser processing of the first main surface, the grinding processing or polishing processing of the second main surface, and the grinding processing or polishing processing of the first main surface have been sequentially performed in the past in addition to the mapping data of the unevenness of the first main surface acquired before the present laser processing.

2. The substrate processing method according to claim 1, wherein the desired data includes the mapping data of the unevenness of the first main surface acquired before laser processing, mapping data of the processing amount in laser processing, and data of the unevenness of the first main surface acquired after grinding processing or polishing processing, the processing conditions include mapping data of the processing amount.

3. A substrate processing method comprising, in sequence, a process of preparing a substrate having a first main surface and a second main surface facing in a direction opposite to that of the first main surface, and having a relief on each of the first main surface and the second main surface; a process of performing laser processing of the first main surface; a process of performing grinding processing or polishing processing of the second main surface; and a process of performing grinding processing or polishing processing of the first main surface, wherein The substrate processing method includes the following processes: acquiring mapping data of the unevenness of the first main surface before laser processing; and and The computer outputs mapping data of the processing amount in the present laser processing by inputting the mapping data of the unevenness of the first main surface acquired before the present laser processing into a model, the model being a model obtained by machine learning of desired data of the substrate after the laser processing of the first main surface, the grinding processing or polishing processing of the second main surface, and the grinding processing or polishing processing of the first main surface have been sequentially performed in the past, the desired data includes the mapping data of the unevenness of the first main surface acquired before laser processing, mapping data of the processing amount in laser processing, and data of the unevenness of the first main surface acquired after grinding processing or polishing processing.

4. The substrate processing method according to claim 2 or 3, including the following processes: The mapping data of the processing amount is divided according to the height, thereby making n layers; a processing area is set for each of the layers; and for each of the layers, a laser light ray is moved in the processing area, wherein n is an integer of 2 or more.

5. The substrate processing method according to claim 4, wherein Further including the following processes: the moving direction of the irradiation point is changed to be perpendicular or inclined between the k-th removed layer and the k+1-th removed layer, where k is an integer of 1 or more and n-1 or less.

6. The substrate processing method according to claim 4, wherein the n layers have the same thickness.

7. The substrate processing method according to claim 4, wherein Further including at least one of the following processes: the position of at least one of a start point at which the movement of the irradiation point is started and an end point at which the movement of the irradiation point is ended is shifted from the periphery of the processing region; and the power density of the irradiation point at the periphery of the processing region is lower than the power density of the irradiation point at the center of the processing region.

8. The substrate processing method according to claim 7, wherein The substrate processing method further includes repeating, in the processing region, a process of moving the irradiation point in a first direction and a process of moving the irradiation point in a second direction, and shifting a position of the irradiation point in a third direction before and after changing a moving direction of the irradiation point between the first direction and the second direction, the second direction being a direction opposite to the first direction, and the third direction being a direction perpendicular to the first direction and the second direction. The substrate processing method further includes shifting a position of at least one of a start point at which the moving of the irradiation point in the first direction is started and an end point at which the moving of the irradiation point in the first direction is ended from a periphery of the processing region.

9. The substrate processing method according to claim 8, wherein The start point and the end point are arranged along the periphery of the processing region in a manner of repeatedly approaching the periphery and moving away from the periphery.

10. The substrate processing method according to claim 9, wherein Trajectories in which the irradiation points adjacent in the third direction move in the first direction and trajectories in which the irradiation points move in the second direction partially overlap in the third direction.

11. A substrate processing apparatus comprising: a conveyance section that conveys a substrate, the substrate having a first main surface and a second main surface facing in a direction opposite to a direction in which the first main surface faces, and having a relief on each of the first main surface and the second main surface; a laser processing section that performs laser processing on the first main surface before performing grinding processing or polishing processing on the second main surface and the first main surface in sequence; and a control circuit that controls the laser processing section, wherein The control circuit controls: acquiring mapping data of the relief of the first main surface before laser processing; and setting a processing condition of the laser processing this time based on desired data of the substrate after laser processing of the first main surface, grinding processing or polishing processing of the second main surface, and grinding processing or polishing processing of the first main surface have been performed in sequence in the past in addition to the mapping data of the relief of the first main surface acquired before the laser processing this time.

12. The substrate processing apparatus according to claim 11, wherein The desired data includes the mapping data of the relief of the first main surface acquired before laser processing, mapping data of a processing amount in laser processing, and data of the relief of the first main surface acquired after grinding processing or polishing processing, The processing condition includes the mapping data of the processing amount.

13. A substrate processing apparatus comprising: a conveyance section that conveys a substrate, the substrate having a first main surface and a second main surface facing in a direction opposite to a direction in which the first main surface faces, and having a relief on each of the first main surface and the second main surface; a laser processing section that performs laser processing on the first main surface before performing grinding processing or polishing processing on the second main surface and the first main surface in sequence; and a control circuit that controls the laser processing section, wherein The control circuit controls as follows: The control circuit controls as follows: The control circuit controls as follows: The control circuit controls as follows:

14. The substrate processing apparatus according to claim 12 or 13, wherein The control circuit controls as follows: The control circuit controls as follows:

15. The substrate processing apparatus of claim 14, wherein, The control circuit controls as follows: The control circuit controls as follows: The control circuit controls as follows: The control circuit controls as follows:

17. 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