Substrate processing method and substrate processing device

Abstract

To provide a technique for quickly removing waviness in a first main surface of a substrate and quickly flattening the first main surface of the substrate.SOLUTION: A substrate processing method includes preparing a substrate having a first main surface and a second main surface facing opposite to the first main surface and having undulations on the first main surface, holding the substrate from below with a holder with the first main surface of the substrate facing upward, and irradiating the first main surface with a laser beam on the basis of a measurement result of the undulations of the first main surface to flatten the first main surface while the substrate is held by the holder. The holder includes a plurality of pins on which the substrate can be placed.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-203823 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique for quickly removing waviness in a first main surface of a substrate and quickly flattening the first main surface of the substrate. [Means for solving the problem]

[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 and having undulations on the first main surface, holding the substrate from below with the first main surface of the substrate facing upward with a holder, and, while the substrate is held by the holder, irradiating the first main surface with a laser beam based on a measurement result of the undulations of the first main surface to flatten the first main surface. The holder includes a plurality of pins on which the substrate can be placed. Effect of the Invention

[0006] According to one aspect of the present disclosure, waviness in the first main surface of the substrate can be removed in a short period of time, and the first main surface of the substrate can be flattened in a short period of time. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a flowchart showing a substrate processing method according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of step S102 in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of the magnitude of waviness of a substrate. [Figure 4] FIG. 4 is a diagram showing an example of step S107 in FIG. [Diagram 5] FIG. 5 is a diagram showing an example of step S110 in FIG. [Figure 6] FIG. 6 is a plan view showing a substrate processing apparatus according to an embodiment. [Figure 7] FIG. 7 is a plan view showing a substrate processing apparatus according to a first modified example. [Figure 8] FIG. 8 is a plan view showing a substrate processing apparatus according to a second modified example. [Figure 9] FIG. 9 is a flowchart showing an example of a process performed by the substrate processing apparatus of FIG. [Figure 10] FIG. 10 is a diagram illustrating an example of a laser processing module. [Figure 11] FIG. 11(A) is a diagram showing a first example of the intensity distribution of a laser beam, and FIG. 11(B) is a diagram showing a second example of the intensity distribution of a laser beam. [Figure 12] Figure 12(A) is a plan view showing a first example of how the irradiation points are arranged, Figure 12(B) is a plan view showing a second example of how the irradiation points are arranged, and Figure 12(C) is a plan view showing a third example of how the irradiation points are arranged. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding configurations are denoted by the same reference numerals, and the description may be omitted. In this specification, 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.

[0009] First, a substrate processing method according to the present embodiment will be described with reference to Figures 1 to 5. The substrate processing method includes steps S101 to S112 shown in Figure 1. Note that the substrate processing method does not need to include all of steps S101 to S112 shown in Figure 1, and may further include steps not shown.

[0010] 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. 6 and the like) described below. The substrate W is loaded into the substrate processing apparatus 1 in a state where it is accommodated in a cassette C.

[0011] 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. 2, 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] 2, step S102 includes measuring the ripple of the substrate W. The ripple measurement is performed using a ripple measurement module 35. The ripple measurement module 35 includes, for example, a holder 351 and measurement heads 352 and 353. The ripple measurement module 35 may include only one of the measurement heads 352 and 353. If the substrate W is inverted, the ripples on both sides of the substrate W can be measured with one measurement head.

[0014] The holder 351 holds the substrate W in a natural state. The natural state is a state in which no external forces (e.g., suction forces) other than gravity and its resistive force are acting on the substrate W. The holder 351 includes, for example, a plurality of pins (e.g., three pins). The substrate W is placed on the plurality of pins. The upper ends of the plurality of pins are disposed on the same horizontal plane HP. The holder 351 holds the substrate W horizontally with the first main surface Wa of the substrate W facing upward.

[0015] The measuring head 352 measures, for example, the height distribution of the upper surface (e.g., the first main surface Wa) of the substrate W. Meanwhile, the measuring head 353 measures the height distribution of the lower surface (e.g., the second main surface Wb) of the substrate W. The reference plane for the height is, for example, the horizontal plane HP. The reference plane for the height may be a crystal plane expressed by desired Miller indices, or a plane inclined by a desired off angle from the crystal plane.

[0016] The measuring heads 352, 353 include, for example, an infrared sensor, a laser displacement meter, or a capacitance sensor. The substrate W is moved horizontally relative to the measuring heads 352, 353 while measuring the distance between the measuring heads 352, 353 and the substrate W, thereby obtaining the height distribution. The measuring heads 352, 353 are of a non-contact type in this embodiment, but may be of a contact type. The measuring heads 352, 353 transmit the measurement data to the control module 9 (see FIG. 6, etc.).

[0017] Step S103 includes setting one of the first main surface Wa and the second main surface Wb of the substrate W, which has a smaller waviness, as the first processed surface to be flattened by the laser beam. Flattening by the laser beam is hereinafter also referred to as laser processing or first processing. In this embodiment, the first processed surface is the second main surface Wb, as shown in FIG.

[0018] Step S103 may also include setting one of the first main surface Wa and the second main surface Wb of the substrate W, which has a larger waviness, as a second processed surface to be flattened by a grinding tool. The flattening process using a grinding tool is hereinafter also referred to as a grinding process or a second process. In this embodiment, the second processed surface is the first main surface Wa, as shown in FIG.

[0019] For example, as shown in Fig. 3, the waviness magnitude ΔZa of the first main surface Wa is expressed by the maximum height difference. Similarly, the waviness magnitude ΔZb of the second main surface Wb is expressed by the maximum height difference. As described above, the reference plane for the height is the horizontal plane HP, but it may be a crystal plane expressed by desired Miller indices, or a plane inclined by a desired off angle from the crystal plane. Note that the waviness magnitudes ΔZa and ΔZb are expressed by the maximum height difference in this embodiment, but may also be expressed by the volume to be removed by flattening.

[0020] However, the first processing (laser processing) has a slower processing speed than the second processing (grinding processing). Therefore, the control module 9 may set the first main surface Wa or the second main surface Wb, whichever has the smaller waviness, as the first processing surface, and set the one with the larger waviness as the second processing surface, based on the measurement results of the waviness of the first main surface Wa and the measurement results of the waviness of the second main surface Wb. This can improve throughput.

[0021] When the magnitude of waviness is the same on the first main surface Wa and the second main surface Wb, the control module 9 may set the upward surface (e.g., the first main surface Wa) as the first processing surface, and the downward surface (e.g., the second main surface Wb) as the second processing surface. The first processing (laser processing) is performed before the second processing (grinding processing). Therefore, if the upward surface is set as the first processing surface, one step of flipping the substrate W can be omitted.

[0022] Step S104 includes determining whether to invert the substrate W based on the measurement results of the undulations of the first main surface Wa and the measurement results of the undulations of the second main surface Wb. For example, the control module determines to invert the substrate W when the first processed surface faces downward, and determines not to invert the substrate W when the first processed surface faces upward.

[0023] If it is necessary to invert the substrate W (step S105, YES), the control module 9 controls the inversion module 38 (see FIG. 6) and the like to invert the substrate W upside down (step S106). On the other hand, if it is not necessary to invert the substrate W (step S105, NO), the control module 9 performs step S107 without performing step S106.

[0024] Step S107 includes irradiating a laser beam onto the first processed surface based on the measurement results of the waviness of one of the first main surface Wa and the second main surface Wb of the substrate W (specifically, the first processed surface) to flatten the first processed surface. As shown in Fig. 4, the laser beam LB is irradiated onto the upper surface of the substrate W. Therefore, the substrate W is held horizontally with the first processed surface facing upward.

[0025] The first processing (laser processing) is performed using a laser processing module 31. The laser processing module 31 irradiates the first processing surface with a laser beam LB, as shown in Fig. 4. The surface layer of the first processing surface absorbs the laser beam LB and either changes state from a solid phase to a gas phase and scatters, or scatters while remaining in the solid phase, and is removed.

[0026] The laser processing module 31 moves the position of the irradiation point P of the laser beam LB within the first processing surface to flatten the first processing surface. The laser beam LB may be irradiated onto the entire first processing surface, or onto only a part of the first processing surface. Even in the latter case, the first processing surface can be flattened.

[0027] The depth of the surface layer removed by irradiation with the laser beam LB is controlled by the cumulative dose (unit: J), which is the product of the output (unit: W) of the laser beam LB and the irradiation time. The greater the cumulative dose, the deeper the surface layer that is removed. Since the first processing surface has waviness, the depth of the surface layer that is removed varies depending on the location within the first processing surface.

[0028] The control module 9 controls the integrated dose of the laser beam LB per unit area of ​​the first processed surface based on the measurement results of the waviness measurement module 35. Since the first processed surface has waviness, the control module 9 changes the integrated dose depending on the location within the first processed surface.

[0029] The control of the cumulative irradiation amount includes one or more selected from the control of the output of the light source 31b and the control of the irradiation time. The control of the irradiation time includes, for example, control of the number of irradiations. The more the number of irradiations, the longer the irradiation time and the deeper the surface layer that is removed. Since the depth of the surface layer that is removed is proportional to the number of irradiations, it is easy to manage the depth of the surface layer that is removed.

[0030] The laser processing module 31 includes a holder 311 that holds the substrate W. The holder 311 holds the substrate W in a natural state. The holder 311 includes, for example, a plurality of pins (for example, three). The substrate W is placed on the plurality of pins. The upper ends of the plurality of pins are arranged on the same horizontal plane. The holder 311 holds the substrate W horizontally with the first processing surface of the substrate W facing upward.

[0031] Unlike step S102 (waviness measurement), step S107 (laser processing) may be performed with the substrate W attached to the horizontal chucking surface of the vacuum chuck. This is because the depth of the surface layer removed by the laser beam LB is determined by the integrated irradiation amount. Note that, if the substrate W is attached, it is possible to prevent the substrate W from shifting from its original position.

[0032] Furthermore, step S107 may include engraving, by the laser beam LB, identification information for identifying the substrate W or the like on the first processed surface of the substrate W. The identification information is engraved in the form of characters (including numbers), a one-dimensional code, a two-dimensional code, or the like.

[0033] Step S108 includes cleaning the first processed surface of the substrate W after planarizing the first processed surface and before planarizing the second processed surface. The cleaning of the first processed surface includes at least one selected from, for example, scrub cleaning and acid cleaning. Debris scattered from the irradiation point P of the laser beam LB and attached to the first processed surface can be removed by cleaning. Step S108 may include cleaning both the first processed surface and the second processed surface. Note that if removal of debris is not required, step S108 is not necessary.

[0034] Step S109 includes inverting the substrate W. Step S109 includes, for example, inverting the substrate W upside down so that the first processed surface of the substrate W faces downward and the second processed surface of the substrate W faces upward.

[0035] Step S110 includes flattening the first processed surface of the substrate W, and then grinding a second processed surface opposite to the first processed surface of the substrate W, and flattening the second processed surface. Before the grinding process, the second processed surface is not laser processed and has waviness.

[0036] 5, the second processed surface is flattened by using a grinding module 51. The grinding module 51 includes a holder 511, a holder driver 512, and a tool driver 513.

[0037] The holder 511 adsorbs the first processed surface of the substrate W and holds the substrate W. The holder 511 is, for example, a vacuum chuck, which adsorbs the first processed surface of the substrate W by vacuum and holds the substrate W horizontally with the second processed surface of the substrate W facing upward. The holder 511 may be an electrostatic chuck.

[0038] The holder driving unit 512 rotates the holder 511, and rotates the substrate W held by the holder 511. The holder driving unit 512 includes, for example, a rotation motor and a transmission mechanism that transmits the rotational driving force of the rotation motor to the holder 511.

[0039] Meanwhile, with the substrate W held by the holder 511, the tool driving unit 513 drives a grinding tool 514 placed in contact with a second processing surface of the substrate W. The grinding tool 514 includes, for example, a disk-shaped grinding wheel 515 and a plurality of grindstones 516 arranged in a ring shape on the lower surface of the grinding wheel 515.

[0040] For example, the tool driving unit 513 includes a rotation motor and a transmission mechanism that transmits the rotational driving force of the rotation motor to the grinding tool 514. The tool driving unit 513 may further include a lifting mechanism that lifts and lowers the grinding tool 514.

[0041] Step S111 includes cleaning the second processed surface of the substrate W after planarizing the second processed surface. Cleaning of the second processed surface includes, for example, scrubbing. Grinding debris adhering to the second processed surface can be removed by cleaning. Step S111 may include cleaning both the first processed surface and the second processed surface.

[0042] Step S112 includes cleaning the second processed surface of the substrate W and then etching the second processed surface. By etching the second processed surface, damage caused during grinding can be removed. Furthermore, by etching the second processed surface, the surface roughness of the second processed surface can be reduced.

[0043] As described above, the substrate processing method of the present embodiment includes planarizing a first processed surface of the substrate W with the laser beam LB, and then planarizing a second processed surface of the substrate W with the grinding tool 514. The second processed surface can be planarized by grinding the second processed surface parallel to the first processed surface that has been previously planarized.

[0044] If the first processed surface is adsorbed to the adsorption surface of the holder 511 in a wavy state, the first processed surface will be flattened according to the adsorption surface. In this state, if the second processed surface is ground parallel to the first processed surface, when the adsorption of the substrate W by the holder 511 is released, not only will the first processed surface return to a wavy state, but the second processed surface will also have the same wavy state as the first processed surface.

[0045] According to this embodiment, the second processed surface can be flattened by grinding the second processed surface parallel to the first processed surface that has been flattened in advance. Also, compared to flattening both sides of the substrate W with a laser beam, the undulations present on both sides of the substrate W can be removed in a short time, and both sides of the substrate W can be flattened in a short time. This is because the processing speed of the laser processing is slower than that of the grinding processing. The reason why both sides of the substrate W are not ground with the grinding tool 514 is that grinding is a technique for making one side of the substrate W parallel to the other side, and flattening does not proceed if both sides of the substrate W have undulations.

[0046] Moreover, according to this embodiment, the substrates W can be planarized one by one, and the processing conditions can be changed for each substrate W. Therefore, both sides of the substrate W can be planarized in a shorter time than when multiple substrates W having different undulations are planarized simultaneously under the same processing conditions. Furthermore, by planarizing the substrates W one by one, it is easy to track the history of the processing conditions for the substrates W, and it is easy to correct the processing conditions for the substrates W based on the processing results of the substrates W. Furthermore, by planarizing the substrates W one by one, the apparatus can be made more compact than when multiple substrates W are planarized simultaneously.

[0047] Next, the substrate processing apparatus 1 according to this embodiment will be described with reference to Fig. 6. The substrate processing apparatus 1 includes a loading / unloading station 2, a first processing station 3, a second processing station 5, and a control module 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.

[0048] The loading / unloading station 2 includes a mounting table 20 and a transport section 23. The mounting table 20 includes a plurality of mounting plates 21. The plurality of mounting plates 21 are arranged in a line in the Y-axis direction. A cassette C is placed on each of the plurality of mounting plates 21. Each cassette C horizontally accommodates a plurality of substrates W arranged at intervals in the vertical direction. The number of mounting plates 21 and the number of cassettes C are not particularly limited.

[0049] The transport section 23 is disposed adjacent to the mounting table 20 on the positive side of the X-axis, and adjacent to the first processing station 3 on the negative side of the X-axis. The transport section 23 is equipped with a transport device 24 that transports the substrate W. The transport device 24 includes a transport arm that holds the substrate W. The transport arm is capable of moving in the horizontal direction (both in the X-axis and Y-axis directions) and the vertical direction, and of rotating about the vertical axis. The transport device 24 transports the substrate W between the cassette C on the mounting table 20 and the first processing station 3.

[0050] The first processing station 3 includes a first processing block G1, a second processing block G2, a third processing block G3, a fourth processing block G4, a first transfer region G5, and a second transfer region G6. The first transfer region G5 is provided in an area surrounded on four sides by the first processing block G1, the second processing block G2, the third processing block G3, and the fourth processing block G4. The second transfer region G6 is provided in an area surrounded on three sides by the second processing block G2, the fourth processing block G4, and the second processing station 5.

[0051] A first transfer device 41 that transfers the substrate W is provided in the first transfer region G5. The first transfer device 41 includes a transfer arm that holds the substrate W. The transfer arm is capable of moving in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction, and of rotating about a vertical axis. The first transfer device 41 transfers the substrate W between the first processing block G1, the second processing block G2, the third processing block G3, and the fourth processing block G4.

[0052] A second transfer device 42 that transfers the substrate W is provided in the second transfer region G6. The second transfer device 42 includes a suction pad that adsorbs the substrate W. The suction pad is capable of moving in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction, and of rotating about a vertical axis. The second transfer device 42 transfers the substrate W between the second processing block G2, the fourth processing block G4, and the second processing station 5.

[0053] The first processing block G1 is disposed on the Y-axis positive side of the first transfer region G5. The first processing block G1 includes, for example, a laser processing module 31. The laser processing module 31 irradiates a first processing surface of the substrate W with a laser beam to flatten the first processing surface.

[0054] The second processing block G2 is disposed on the Y-axis negative side of the first transfer region G5. The second processing block G2 includes, for example, a cleaning module 32 and an etching module 33. The cleaning module 32 cleans the substrate W after grinding. The etching module 33 etches the substrate W after grinding. The etching module 33 etches the second processing surface of the substrate W, but may also etch the first processing surface of the substrate W. The etching module 33 for the second processing surface and the etching module 33 for the first processing surface may be provided separately. The cleaning module 32 and the etching module 33 are stacked. The stacking order is not limited to the order in FIG. 6.

[0055] The third processing block G3 is disposed on the negative X-axis direction side of the first transfer region G5. The third processing block G3 includes, for example, a transition module 34, a swell measurement module 35, and an inversion module 36. The transition module 34 transfers the substrate W between the transfer device 24 of the loading / unloading station 2 and the first transfer device 41 of the first processing station 3. The swell measurement module 35 measures the swell of the first main surface Wa and the second main surface Wb of the substrate W. The inversion module 36 inverts the substrate W. The transition module 34, the swell measurement module 35, and the inversion module 36 are stacked. The stacking order is not limited to the order in FIG. 6.

[0056] In addition, when it is determined in advance which of the first principal surface Wa and the second principal surface Wb is the first processed surface (laser processed surface), the waviness measuring module 35 may measure the waviness of only the first processed surface. For example, when the top surface of the substrate W is determined to be the first processed surface, the waviness measuring module 35 may measure the waviness of only the top surface of the substrate.

[0057] The fourth processing block G4 is disposed on the X-axis positive side of the first transfer region G5. The fourth processing block G4 includes, for example, a cleaning module 37, an inversion module 38, and an alignment module 39. The cleaning module 37 cleans the substrate W after laser processing but before grinding processing. The inversion module 38 inverts the substrate W. The alignment module 39 detects the center of the substrate W. In addition, the alignment module 39 detects the notch of the substrate W. The cleaning module 37, the inversion module 38, and the alignment module 39 are stacked. The stacking order is not limited to the order in FIG. 6.

[0058] It should be noted that the first processing station 3 only needs to have at least the laser processing module 31. The type, arrangement, and number of modules constituting the first processing station 3 are not limited to those shown in FIG.

[0059] The second processing station 5 includes, for example, a grinding module 51. The grinding module 51 grinds the second processed surface of the substrate W to flatten the second processed surface.

[0060] The control module 9 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed in the substrate processing apparatus 1. The control module 9 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the programs stored in the storage medium 92.

[0061] Next, the operation of the substrate processing apparatus 1 according to this embodiment will be described with reference to Fig. 1 again. Steps S101 to S112 shown in Fig. 1 are performed under the control of the control module 9.

[0062] First, an external transfer device transfers the substrate W into the load / unload station 2 of the substrate processing apparatus 1 (step S101). A cassette C containing the substrate W is placed on the mounting table 20. Next, the transfer device 24 removes the substrate W from the cassette C on the mounting table 20, and transfers it to the transition module 34. Subsequently, the first transfer device 41 of the first processing station 3 receives the substrate W from the transition module 34, and transfers it to the waviness measurement module 35.

[0063] Next, the undulation measuring module 35 measures the undulations of the first main surface Wa and the second main surface Wb of the substrate W (step S102). The undulation measuring module 35 transmits the measurement data to the control module 9.

[0064] Next, the control module 9 sets one of the first main surface Wa and the second main surface Wb of the substrate W, which has a smaller waviness, as the first processed surface (laser processed surface) (step S103). In addition, the control module 9 determines whether to turn over the substrate W (step S104).

[0065] If the substrate W needs to be inverted (step S105, YES), the first transfer device 41 receives the substrate W from the waviness measurement module 35 and transfers it to the inversion module 36. Then, the inversion module 36 inverts the substrate W upside down (step S106). After that, the first transfer device 41 receives the substrate W from the inversion module 36 and transfers it to the laser processing module 31.

[0066] On the other hand, if there is no need to turn over the substrate W (step S105, NO), the first transfer device 41 receives the substrate W from the waviness measurement module 35 and transfers it to the laser processing module 31.

[0067] Next, the laser processing module 31 irradiates a laser beam onto the first processed surface based on the measurement result of the waviness of the first processed surface of the substrate W, and flattens the first processed surface (step S107). Thereafter, the first transfer device 41 receives the substrate W from the laser processing module 31, and transfers it to the cleaning module 37.

[0068] Next, the cleaning module 37 cleans the first processing surface of the substrate W (step S108). The cleaning module 37 may also clean the second processing surface of the substrate W. Thereafter, the first transfer device 41 receives the substrate W from the cleaning module 37 and transfers it to the inversion module .

[0069] Next, the inversion module 38 turns the substrate W upside down (step S109). Thereafter, the first transfer device 41 receives the substrate W from the inversion module 38 and transfers it to the alignment module 39.

[0070] Next, the alignment module 39 detects the center of the substrate W. The center of the substrate W can be aligned with the rotation centerline of the holder 511 of the grinding module 51. The alignment module 39 may detect a notch of the substrate W. In a rotating coordinate system that rotates together with the holder 511, the crystal orientation of the substrate W can be aligned to a desired orientation. The second transfer device 42 receives the substrate W from the alignment module 39 and transfers it to the grinding module 51 of the second processing station 5.

[0071] Next, the grinding module 51 grinds the second processed surface of the substrate W to flatten the second processed surface (step S110). Thereafter, the second transfer device 42 receives the substrate W from the grinding module 51 and transfers it to the cleaning module 32.

[0072] Next, the cleaning module 32 cleans the second processing surface of the substrate W (step S111). The cleaning module 32 may also clean the first processing surface of the substrate W. Thereafter, the first transfer device 41 receives the substrate W from the cleaning module 32 and transfers it to the etching module 33.

[0073] Next, the etching module 33 etches the second processing surface of the substrate W (step S112). The etching module 33 may also etch the first processing surface of the substrate W. Thereafter, the first transfer device 41 receives the substrate W from the etching module 33 and transfers it to the transition module .

[0074] The etching of the first work surface may occur after the etching of the second work surface, in which case the flip module 38 may flip the substrate W after the etching of the second work surface and before the etching of the first work surface.

[0075] The etching of the first processing surface may be performed before the etching of the second processing surface, the etching of the first processing surface may be performed simultaneously with the etching of the second processing surface, or the etching solution may be supplied simultaneously to both the upper and lower surfaces of the horizontal substrate W.

[0076] However, when the etching liquid is supplied from below the substrate W, etching is more likely to become uneven and the uniformity of the thickness of the substrate W is more likely to decrease than when the etching liquid is supplied from above the substrate W.

[0077] When both the first and second processed surfaces are etched, it is preferable to turn the first and second processed surfaces upward in that order and supply the etching liquid to the upward surface, which can improve the uniformity of the thickness of the substrate W.

[0078] The main purpose of etching the second processed surface is to improve the thickness uniformity over the entire surface of the substrate and to remove the grinding marks. If there are no grinding marks, the main purpose of etching the second processed surface is to improve the thickness uniformity over the entire surface of the substrate.

[0079] The purpose of etching the first processed surface is to remove contaminants that have adhered to the first processed surface during grinding and to remove scars from laser processing. If there are no scars from laser processing, the main purpose of etching the first processed surface is to remove contaminants. This is particularly effective for removing contaminants that contain metal components that are difficult to remove by cleaning.

[0080] Next, the transport device 24 of the load-unloading station 2 receives the substrate W from the transition module 34, and transports it to the cassette C on the mounting table 20. The substrate W is unloaded from the substrate processing apparatus 1 while still accommodated in the cassette C. This completes the processing of the substrate W.

[0081] Next, a substrate processing apparatus 1 according to a first modified example will be described with reference to Fig. 7. The substrate processing apparatus 1 according to this modified example performs steps S101 to S109 among steps S101 to S112 shown in Fig. 1. Note that step S109 may be performed by the substrate processing apparatus 1 according to a second modified example, which will be described later. Below, differences between this modified example and the above embodiment will be mainly described.

[0082] The substrate processing apparatus 1 includes a loading / unloading station 2, a processing station 3, and a control module 9. The loading / unloading station 2 and the processing station 3 are disposed in this order from the negative side in the X-axis direction to the positive side in the X-axis direction.

[0083] The processing station 3 includes a first processing block G1, a second processing block G2, a third processing block G3, and a transfer area G5. The transfer area G5 is provided in an area surrounded on three sides by the first processing block G1, the second processing block G2, and the third processing block G3.

[0084] The transfer region G5 is provided with a transfer device 41 that transfers the substrate W. The transfer device 41 transfers the substrate W between the first processing block G1, the second processing block G2, and the third processing block G3.

[0085] The first processing block G1 is disposed on the Y-axis positive side of the transfer region G5. The first processing block G1 includes, for example, a laser processing module 31.

[0086] The second processing block G2 is disposed on the Y-axis negative side of the transfer region G5. The second processing block G2 includes, for example, a cleaning module 37. The cleaning module 37 cleans the substrate W after the laser processing and before the grinding processing.

[0087] The third processing block G3 is disposed on the negative X-axis direction side of the transfer region G5. The third processing block G3 includes, for example, a transition module , a waviness measurement module 35, and an inversion module .

[0088] Next, the operation of the substrate processing apparatus 1 according to the first modified example will be described with reference to Fig. 1 again. Of steps S101 to S112 shown in Fig. 1, steps S101 to S109 are performed under the control of the control module 9.

[0089] The description of steps S101 to S108 is the same as that of the above embodiment, and therefore will be omitted. After step S108, the transfer device 41 receives the substrate W from the cleaning module 37, and transfers it to the inversion module .

[0090] Next, the inversion module turns the substrate W upside down (step S109). Thereafter, the transport device 41 receives the substrate W from the inversion module and transports it to the transition module .

[0091] As described above, the substrate processing apparatus 1 does not need to perform step S109. In this case, after step S108, the transfer device 41 receives the substrate W from the cleaning module 37 and transfers it to the transition module .

[0092] Next, the transport device 24 of the load-unloading station 2 receives the substrate W from the transition module 34, and transports it to the cassette C on the mounting table 20. The substrate W is unloaded from the substrate processing apparatus 1 while still accommodated in the cassette C. This completes the processing of the substrate W.

[0093] Next, a substrate processing apparatus 1 according to a second modified example will be described with reference to Fig. 8. The substrate processing apparatus 1 according to this modified example performs steps S110 to S112 among steps S101 to S112 shown in Fig. 1. The substrate processing apparatus 1 may also perform step S109. The following mainly describes the differences between this modified example and the above embodiment.

[0094] The substrate processing apparatus 1 includes a loading / unloading station 2, a first processing station 3, a second processing station 5, and a control module 9.

[0095] The first processing station 3 includes a first processing block G1, a second processing block G2, a third processing block G3, and a transfer area G6. The transfer area G6 is provided in an area surrounded on three sides by the first processing block G1, the second processing block G2, and the third processing block G3.

[0096] The transfer region G6 is provided with a transfer device 42 for transferring the substrate W. The transfer device 42 transfers the substrate W between the first processing block G1, the second processing block G2, the third processing block G3, and the second processing station 5.

[0097] The first processing block G1 is disposed on the Y-axis positive side of the first transfer region G5. The first processing block G1 includes, for example, a cleaning module 43 and an alignment module 39. The cleaning module 43 cleans the substrate W after laser processing and before grinding processing.

[0098] The second processing block G2 is disposed on the Y-axis negative side of the first transfer region G5. The second processing block G2 includes, for example, a cleaning module 32 and an etching module 33. The cleaning module 32 cleans the substrate W after grinding. The etching module 33 etches the substrate W after grinding. The etching module 33 etches the second processing surface of the substrate W, but may also etch the first processing surface of the substrate W. The etching module 33 for the second processing surface and the etching module 33 for the first processing surface may be provided separately.

[0099] The third processing block G3 is disposed on the negative X-axis direction side of the first transfer region G5. The third processing block G3 includes, for example, a transition module 34, a swell measurement module 35, and an inversion module 36. The swell measurement module 35 measures the swells of both the first main surface Wa and the second main surface Wb of the substrate W. The inversion module 36 inverts the substrate W.

[0100] The second processing station 5 includes, for example, a grinding module 51. The grinding module 51 grinds the second processed surface of the substrate W to flatten the second processed surface.

[0101] Next, the operation of the substrate processing apparatus 1 according to the second modified example will be described with reference to Fig. 9. Steps S201 to S207 and S110 to S112 shown in Fig. 9 are performed under the control of the control module 9.

[0102] First, an external transfer device transfers the substrate W after laser processing into the load / unload station 2 of the substrate processing apparatus 1. A cassette C containing the substrate W after laser processing is placed on the mounting table 20. Next, the transfer device 24 takes out the substrate W from the cassette C on the mounting table 20, and transfers it to the transition module 34. Subsequently, the transfer device 42 of the first processing station 3 receives the substrate W from the transition module 34, and transfers it to the waviness measurement module 35.

[0103] Next, the undulation measuring module 35 measures the undulations of both the first main surface Wa and the second main surface Wb of the substrate W (step S201). The undulation measuring module 35 transmits the measurement data to the control module 9.

[0104] Next, the control module 9 sets the first main surface Wa or the second main surface Wb of the substrate W, whichever has the larger waviness, as the second processed surface (grinding surface) (step S202). The surface with the smaller waviness has already been laser processed and flattened.

[0105] Next, the control module 9 determines whether to invert the substrate W (step S203). For example, the control module determines to invert the substrate W when the second processing surface faces downward, and determines not to invert the substrate W when the second processing surface faces upward.

[0106] If the substrate W needs to be inverted (step S204, YES), the transport device 42 receives the substrate W from the waviness measurement module 35 and transports it to the inversion module 36. Then, the inversion module 36 inverts the substrate W upside down (step S205). Thereafter, the transport device 42 receives the substrate W from the inversion module 36 and transports it to the cleaning module 43.

[0107] On the other hand, if there is no need to invert the substrate W (step S204, NO), the transport device 42 receives the substrate W from the waviness measurement module 35 and transports it to the cleaning module 43.

[0108] Next, the cleaning module 43 cleans the substrate W (step S206). For example, the cleaning module 43 scrubs the substrate W. Thereafter, the transport device 42 receives the substrate W from the cleaning module 43 and transports it to the alignment module 39. Note that if the substrate W is clean, step S206 does not need to be performed.

[0109] Next, the alignment module 39 detects the center of the substrate W (step S207). The center of the substrate W can be aligned with the rotation center line of the holder 511 of the grinding module 51. The alignment module 39 may detect a notch of the substrate W. In a rotating coordinate system that rotates together with the holder 511, the crystal orientation of the substrate W can be aligned to a desired orientation. The transfer device 42 receives the substrate W from the alignment module 39 and transfers it to the grinding module 51 of the second processing station 5.

[0110] Thereafter, steps S110 to S112 are carried out. The explanation of steps S110 to S112 is omitted since it is similar to the explanation of the above embodiment.

[0111] Next, an example of the laser processing module 31 will be described with reference to Fig. 10. The laser processing module 31 includes a holder 311, a light source 312, and a galvanometer scanner 313 which is a moving part. The laser processing module 31 also includes an fθ lens 314, a homogenizer 315, and an aperture 316.

[0112] The holder 311 holds the substrate W. For example, the holder 311 holds the substrate W horizontally from below with the laser processing surface of the substrate W facing upward. The holder 311 holds the substrate W in a natural state without suction. The holder 311 may suction the substrate W, or may be a vacuum chuck or an electrostatic chuck.

[0113] The light source 312 oscillates a laser beam LB to be irradiated onto the upper surface of the substrate W. The laser beam LB is absorbent for the substrate W. If the substrate W is a silicon wafer, the laser beam LB is, for example, UV light. The substrate W absorbs the laser beam LB and either changes state from a solid phase to a gas phase and disperses, or disperses while remaining in the solid phase. As a result, the upper surface of the substrate W can be flattened. The laser beam LB may be focused and irradiated onto the upper surface of the substrate W. The irradiation point P is the focused point where the power density is highest, but it does not have to be the focused point.

[0114] The light source 312 is, for example, a pulsed laser. The irradiation time per pulse is, for example, 30 nsec or less. If the irradiation time per pulse is 30 nsec or less, the laser beam LB with a high power density can be irradiated to the substrate W in a short time, and overheating of the substrate W can be suppressed. Therefore, deterioration of the substrate W due to heat can be suppressed, for example, the occurrence of a discolored layer can be suppressed. The irradiation time per pulse is preferably 10 psec or less. If the irradiation time per pulse is 10 psec or less, deterioration of the substrate W due to heat can be suppressed even if irradiation points P are formed multiple times at the same location.

[0115] The galvano scanner 313 is disposed, for example, above the substrate W held by the holder 311. The galvano scanner 313 makes it possible to move the position of the irradiation point P of the laser beam LB on the upper surface of the substrate W without moving the holder 311. Even when the holder 311 does not adsorb the substrate W, as long as the holder 311 does not move, no positional deviation of the substrate W with respect to the holder 311 occurs. Therefore, the position of the irradiation point P can be controlled with high precision.

[0116] The galvanometer scanner 313 includes two pairs (only one pair is shown in FIG. 10) of a galvanometer mirror 317 and a galvanometer motor 318. One galvanometer motor 318 rotates one galvanometer mirror 317 to displace the irradiation point P in the X-axis direction. Another galvanometer motor 318 rotates another galvanometer mirror 317 to displace the irradiation point P in the Y-axis direction.

[0117] It should be noted that the moving unit in this embodiment is the galvano scanner 313, but the technology of the present disclosure is not limited thereto. The moving unit may be any unit that moves the position of the irradiation point P of the laser beam LB on the upper surface of the substrate W while the substrate W is held by the holder 311. For example, the moving unit may be a unit that moves the holder 311 in the X-axis direction and the Y-axis direction, and may have a motor and a ball screw mechanism that converts the rotational motion of the motor into linear motion of the holder 311. The moving unit may also have a mechanism that rotates the holder 311 around a vertical axis.

[0118] The fθ lens 314 forms a focal plane perpendicular to the Z-axis direction. While the galvanometer scanner 313 moves the position of the irradiation point P in the X-axis direction or the Y-axis direction, the fθ lens 314 maintains the Z-axis position of the irradiation point P on the focal plane, and also maintains the shape and dimensions of the irradiation point P on the focal plane. As a result, as will be described later, rectangular irradiation points P can be two-dimensionally arranged regularly and without gaps on the upper surface of the substrate W. The height of the irradiation point P is the height of the focal plane.

[0119] The homogenizer 315 converts the intensity distribution of the laser beam LB from the Gaussian distribution shown in FIG. 11(A) to a top-hat distribution shown in FIG. 11(B), and homogenizes the intensity distribution.

[0120] Aperture 316 shapes the cross-sectional shape of laser beam LB into a rectangle. Rectangles include not only rectangular shapes but also square shapes. Aperture 316 is a light-shielding film with a rectangular opening. The opening allows laser beam LB to pass through within the range indicated by arrow D in FIG. 11(B), for example.

[0121] A rectangular irradiation spot P with a uniform intensity distribution can be formed by the homogenizer 315 and the aperture 316. By arranging the irradiation spots P two-dimensionally in a regular manner without gaps as described later, the integrated irradiation amount of the laser beam LB per unit area can be controlled with high precision.

[0122] As shown in Fig. 12(A), the irradiation point P is a rectangle with a uniform intensity distribution, two sides of the rectangle are parallel to the X-axis direction, and the remaining two sides of the rectangle are parallel to the Y-axis direction. The X-axis dimension X0 of the irradiation point P may be the same as or different from the Y-axis dimension Y0 of the irradiation point P. This is the same in Fig. 12(B) and Fig. 12(C).

[0123] 12(A), while oscillating the laser beam LB in pulses, the control module 9 moves the irradiation point P in the X-axis direction by X0 during the pulse off time, and arranges the irradiation points P in a line without gaps over the entire X-axis direction of the upper surface of the substrate W. Thereafter, while oscillating the laser beam LB in pulses, the control module 9 repeatedly moves the irradiation point P in the Y-axis direction by Y0 during the pulse off time and moves the irradiation point P in the X-axis direction by X0 during the pulse off time, and arranges the irradiation points P two-dimensionally without gaps over the entire upper surface of the substrate W.

[0124] Alternatively, as shown in FIG. 12(B), the control module 9, while oscillating the laser beam LB in pulses, moves the irradiation point P in the X-axis direction by half the value of X0 during the off-time of the pulse, and arranges the irradiation points P in a line while overlapping them over the entire X-axis direction of the upper surface of the substrate W. Thereafter, while oscillating the laser beam LB in pulses, the control module 9 repeats moving the irradiation point P in the Y-axis direction by Y0 during the off-time of the pulse and moving the irradiation point P in the X-axis direction by half the value of X0 during the off-time of the pulse, and arranges the irradiation points P two-dimensionally without gaps over the entire upper surface of the substrate W. Note that the control module 9 may move the irradiation point P by half the value of Y0 instead of moving the irradiation point P in the Y-axis direction by Y0 during the off-time of the pulse.

[0125] Alternatively, as shown in FIG. 12(C), the control module 9, while oscillating the laser beam LB in a pulsed manner, moves the irradiation point P in the X-axis direction by twice the distance X0 during the off-time of the pulse, and arranges the irradiation points P in a line while forming a gap SP over the entire X-axis direction of the upper surface of the substrate W. Next, the control module 9, while oscillating the laser beam LB in a pulsed manner again, moves the irradiation point P in the X-axis direction by twice the distance X0 during the off-time of the pulse so as to fill the gap SP with the irradiation point P. Thereafter, the control module 9, while oscillating the laser beam LB in a pulsed manner, moves the irradiation point P in the Y-axis direction by Y0 during the off-time of the pulse, moves the irradiation point P in the X-axis direction by twice the distance X0 during the off-time of the pulse, and repeats moving the irradiation point P in the X-axis direction by twice the distance X0 during the off-time of the pulse so as to fill the gap SP with the irradiation point P, and arranges the irradiation points P two-dimensionally without gaps.

[0126] Although the embodiments of the substrate processing method and the 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.

[0127] This application claims priority based on Patent Application No. 2021-008295 filed with the Japan Patent Office on January 21, 2021, and the entire contents of Patent Application No. 2021-008295 are incorporated by reference into this application. [Explanation of symbols]

[0128] 1 Substrate processing equipment 9 Control module (control section) 31 Laser Processing Module 311 Holding part 312 Light source 313 Mobile Division

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 having undulations; holding the substrate from below with a holding part with the first main surface of the substrate facing upward; irradiating a laser beam onto the first main surface based on a measurement result of the waviness of the first main surface while the substrate is held by the holding part, thereby flattening the first main surface; Including, The substrate processing method, wherein the holding portion includes a plurality of pins on which the substrate is placed.

2. The substrate processing method according to claim 1 , wherein upper ends of the pins of the holding portion are arranged on the same horizontal plane.

3. 3. The substrate processing method according to claim 1 or 2, further comprising grinding the second main surface while the first main surface, which has been planarized by irradiation with the laser beam, is adsorbed to a second holding portion, thereby planarizing the second main surface.

4. holding the substrate from below with a third holding part with the first main surface facing upward before irradiating the first main surface with the laser beam; measuring a waviness of the first main surface of the substrate while the substrate is held by the third holding part; Including, The substrate processing method according to any one of claims 1 to 3, wherein the third holding portion includes a plurality of pins on which the substrate is placed, and upper ends of the plurality of pins of the third holding portion are arranged on the same horizontal plane.

5. a holding part that holds a substrate from below, the substrate having a first main surface and a second main surface facing opposite to the first main surface and having undulations on the first main surface with the first main surface facing upward; a light source that oscillates a laser beam to be irradiated onto the first main surface of the substrate; a moving unit that moves a position of an irradiation point of the laser beam on the first main surface of the substrate in a state in which the substrate is held by the holding unit; a control unit that controls the moving unit based on a measurement result of the waviness of the first main surface of the substrate and flattens the first main surface of the substrate; Equipped with The substrate processing apparatus, wherein the holding portion includes a plurality of pins on which the substrate is placed.

6. The substrate processing apparatus according to claim 5 , wherein upper ends of the pins of the holding portion are arranged on the same horizontal plane.

7. a second holder that adsorbs the first main surface that has been planarized by the irradiation of the laser beam and holds the substrate; a tool driving unit that drives a grinding tool that is in contact with the second main surface while the substrate is held by the second holding unit; and The substrate processing apparatus according to claim 5 or 6, comprising:

8. a third holding portion that holds the substrate from below with the first main surface of the substrate facing upward; a measurement head that measures waviness of the first main surface of the substrate while the substrate is held by the third holding part; Equipped with The substrate processing apparatus according to any one of claims 5 to 7, wherein the third holding portion includes a plurality of pins on which the substrate is placed, and upper ends of the plurality of pins of the third holding portion are arranged on the same horizontal plane.

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