processing device

Abstract

The processing apparatus of the present application forms a modification point constituting a modification region in a processing target. The processing apparatus of the present application includes a first irradiation section that irradiates a first light to the processing target to temporarily increase an absorption rate in a part of the processing target before the irradiation of the first light, and a second irradiation section that irradiates a second light to the part of the processing target during the period in which the absorption rate in the part of the processing target is temporarily increased.

Description

[0001] (This application is a divisional application of patent application No. 201980010433.6 filed on January 23, 2019, with the title of "Processing device".)

[0002] Technical Field

[0003] An aspect of the present application relates to a processing device. BACKGROUND

[0004] In the related art, a processing device that forms a modification point constituting a modification region in a processing target is known. As such a technology, for example, a laser processing device is described in Patent Literature 1. According to the laser processing device described in Patent Literature 1, a modification point is formed inside a processing target by irradiating laser light to the processing target.

[0005] [Related Art Documents]

[0006] [Patent Literature]

[0007] [Patent Literature 1] Japanese Patent Application Publication No. 2015-186825 SUMMARY

[0008] [Problems to be Solved by the Invention]

[0009] In recent years, the above-described processing device is gradually applied in various fields, and thus, it is desired to develop a high added-value product that can be easily applied to various processing requirements (for example, high division force, suppression of damage to a processing target, or both of these properties, etc.).

[0010] Here, an aspect of the present application aims to provide a processing device with high added value.

[0011] [Means for Solving the Problems]

[0012] As a result of diligent research by the present inventors, when a modification point is formed in a processing target by irradiation of light, a characteristic phenomenon was found during a period from the start to the end. Specifically, by irradiation of light to a processing target, the absorption rate of a part of the region of the processing target (for example, the vicinity of the focal point of the light. Hereinafter, sometimes simply referred to as "part of the region") temporarily rises (first stage). By irradiating light to the part of the region where the absorption rate temporarily rises, energy is injected to the part of the region, and the part of the region in a high temperature state is enlarged (second stage). As a result, it was found that a modification point is formed in the processing target. Furthermore, it was found that, by utilizing this characteristic phenomenon, various processing requirements can be easily dealt with, and the added value of the device can be improved, thereby completing the requirements of an aspect of the present application.

[0013] That is, one aspect of the present application relates to a processing device that forms a modification point constituting a modification region in a processing target, and the processing device includes a first irradiation section that irradiates first light to the processing target to temporarily increase an absorption rate in a part of the processing target, and a second irradiation section that irradiates second light to the part of the processing target during the absorption rate in the part of the processing target is temporarily increased.

[0014] In the processing device, the first light is irradiated to the processing target to temporarily increase the absorption rate in the part of the processing target, and the second light is irradiated to the part of the processing target during the absorption rate in the part of the processing target is temporarily increased, thereby forming the modification point. Thus, each time the modification point is formed, the light can be irradiated by being classified into the first light and the second light according to each phenomenon of the first stage and the second stage, respectively. By appropriately changing various parameters and irradiation methods of the first light and the second light, respectively, various processing requirements can be easily dealt with. Thus, a processing device with high added value can be realized.

[0015] In the processing device of one aspect of the present application, the energy of the second light can be higher than the energy of the first light. Thus, the first light and the second light can be further irradiated according to each phenomenon of the first stage and the second stage.

[0016] In the processing device of one aspect of the present application, the peak intensity of the second light can be lower than the peak intensity of the first light. Thus, the first light and the second light can be further irradiated according to each phenomenon of the first stage and the second stage.

[0017] In the processing device of one aspect of the present application, the wavelength of the second light can be different from the wavelength of the first light. By appropriately making the wavelength of the first light and the wavelength of the second light different, the absorption of the first light and the second light in the processing target and the processing result can be controlled.

[0018] In the processing device of one aspect of the present application, the second light can be light that does not form the modification point when the second light is irradiated alone to the processing target. In this case, the second light does not form the modification point even if the second light is irradiated in a conventional manner or is irradiated in advance, and the first light functions as a trigger that starts the formation of the modification point. The timing of the irradiation of the second light does not need to be precisely controlled.

[0019] In the processing device of one aspect of the present application, the irradiation direction of the second light to the processing target can be different from the irradiation direction of the first light to the processing target. By appropriately making the irradiation direction of the first light and the irradiation direction of the second light different, the direction in which the modification point expands when the modification point is formed and the position of the modification region can be controlled.

[0020] In the processing apparatus of one aspect of the present application, it can also be that the angle at which the second light is focused on the focusing position of the second light is different from the angle at which the first light is focused on the focusing position of the first light. By making the angle at which the first light is focused on the focusing position of the first light and the angle at which the second light is focused on the focusing position of the second light appropriately different, it is possible to control the width of the processing region.

[0021] In the processing apparatus of one aspect of the present application, it can also be that the beam profile of the second light is different from the beam profile of the first light. By making the beam profile of the first light and the beam profile of the second light appropriately different, it is possible to control the dividing force and the damage to the processing target.

[0022] In the processing apparatus of one aspect of the present application, it can also be that the M 2 value of the second light is different from the M 2 value of the first light. By making the M 2 value of the first light and the M 2 value of the second light appropriately different, it is possible to achieve simplification of the apparatus.

[0023] In the processing apparatus of one aspect of the present application, it can also be that the pulse width of the second light is different from the pulse width of the first light. By making the pulse width of the first light and the pulse width of the second light appropriately different, it is possible to further irradiate the first light and the second light in accordance with the respective phenomena of the first stage and the second stage.

[0024] In the processing apparatus of one aspect of the present application, it can also be that the pulse waveform of the second light is different from the pulse waveform of the first light. By making the pulse waveform of the first light and the pulse waveform of the second light appropriately different, it is possible to further irradiate the first light and the second light in accordance with the respective phenomena of the first stage and the second stage.

[0025] In the processing apparatus of one aspect of the present application, it can also be that the polarization direction of the second light is different from the polarization direction of the first light. By making the polarization direction of the first light and the polarization direction of the second light appropriately different, it is possible to further irradiate the first light and the second light in accordance with the respective phenomena of the first stage and the second stage.

[0026] In the processing apparatus of one aspect of the present application, it can also be that the modification region is a cut start region in which the processing target is cut in the thickness direction. In this case, the processing target can be cut in the thickness direction with the modification region as the start of the cut.

[0027] In the processing apparatus of one aspect of the present application, it can also be that the modification region is a cut start region in which the processing target is cut in a direction intersecting the thickness direction. In this case, the processing target can be cut (e.g., sliced) in a direction intersecting the thickness direction with the modification region as the start of the cut.

[0028] In the processing apparatus of one aspect of the present application, the modified region can also be a predetermined region removed in two dimensions or three dimensions in the processing target. In this case, the modified region is selectively removed by etching or the like, and thus a space extending in two dimensions or three dimensions can be formed in the processing target.

[0029] In the processing apparatus of one aspect of the present application, the modified region can also be a crystal region, a recrystallized region, or a gettered region formed in the inside of the processing target. In this case, the modified region can be utilized as the crystal region, the recrystallized region, or the gettered region.

[0030] In the processing apparatus of one aspect of the present application, the first irradiation section can be constituted by a first light source that emits first light, and the second irradiation section can be constituted by a second light source that emits second light and a control section that controls the timing of irradiation of the second light source in such a manner that the second light is irradiated toward the partial region during the period in which the absorption rate is rising. In this case, the processing apparatus of one aspect of the present application can be constituted by a plurality of light sources.

[0031] In the processing apparatus of one aspect of the present application, the first irradiation section and the second irradiation section can be constituted by a light source and an external modulator that modulates light emitted from the light source, a part of the light emitted from the light source and modulated by the external modulator being irradiated toward the processing target as first light, and the other part of the light emitted from the light source and modulated by the external modulator being irradiated toward the partial region as second light during the period in which the absorption rate is rising. In this case, the processing apparatus of one aspect of the present application can be constituted by the same one light source.

[0032] [Effects of Invention]

[0033] According to one aspect of the present application, a processing apparatus having high added value can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0034] [ Figure 1 ] Figure 1 is a schematic configuration view of a laser processing apparatus used when forming a modified region.

[0035] [ Figure 2 ] Figure 2 is a plan view of a processing target that becomes an object of forming a modified region.

[0036] [ Figure 3 ] Figure 3 is Figure 2 is a sectional view of the III-III line of the processing target of

[0037] [ Figure 4 ] Figure 4is a plan view of a processed object after laser processing.

[0038] [ Figure 5 ] Figure 5 is a cross-sectional view of a V-V line of the processed object of Figure 4 .

[0039] [ Figure 6 ] Figure 6 is a cross-sectional view of a VI-VI line of the processed object of Figure 4 .

[0040] [ Figure 7 ] Figure 7 is a diagram illustrating a formation mechanism of a modified point.

[0041] [ Figure 8 ] Figure 8 is a photographic view showing a cross section of the processed object after formation of a modified point.

[0042] [ Figure 9 ] Figure 9 is a schematic view showing a structure of a laser processing apparatus of the first embodiment.

[0043] [ Figure 10 ] Figure 10 is a diagram illustrating a first laser, a second laser, and an absorption rate.

[0044] [ Figure 11 ] Figure 11 is a schematic view showing a structure of a laser processing apparatus of a first modification of the first embodiment.

[0045] [ Figure 12 ] Figure 12 is a schematic view showing a structure of a laser processing apparatus of a second modification of the first embodiment.

[0046] [ Figure 13 ] Figure 13 is a schematic view showing a structure of a laser processing apparatus of a third modification of the first embodiment.

[0047] [ Figure 14 ] Figure 14 is a schematic view showing a structure of a laser processing apparatus of the second embodiment.

[0048] [ Figure 15 ] Figure 15 is a schematic view showing a structure of a laser processing apparatus of a modification of the second embodiment.

[0049] [ Figure 16 ] Figure 16 is a schematic view showing a structure of a laser processing apparatus of the third embodiment.

[0050] [Figure 17 ] Figure 17 This is a schematic diagram showing the structure of a laser processing apparatus according to a modified example of the third embodiment.

[0051] [ Figure 18 ] Figure 18 This is a schematic diagram showing the structure of the laser processing apparatus according to the fourth embodiment.

[0052] [ Figure 19 ] Figure 19 This is a schematic diagram showing the structure of the laser processing apparatus according to the fifth embodiment.

[0053] [ Figure 20 ] Figure 20 This is a schematic diagram showing the structure of the laser processing apparatus according to the sixth embodiment.

[0054] [ Figure 21 ] Figure 21 This is a schematic diagram showing the structure of the laser processing apparatus according to the seventh embodiment.

[0055] [ Figure 22 ] Figure 22 This is a schematic diagram showing the structure of a laser processing apparatus according to a modified example of the seventh embodiment.

[0056] [ Figure 23 ] Figure 23 This is a schematic diagram showing the structure of the laser processing apparatus according to the eighth embodiment.

[0057] [ Figure 24 ] Figure 24 This is a schematic diagram showing the structure of a laser processing apparatus according to a modified example of the eighth embodiment.

[0058] [ Figure 25 ] Figure 25 This is a schematic diagram showing the structure of the laser processing apparatus according to the ninth embodiment. Detailed Implementation

[0059] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in the various drawings, the same symbol will be used to label the same or equivalent parts, and repeated descriptions will be omitted.

[0060] [Formation of the modified zone]

[0061] The processing apparatus of this embodiment forms modified points constituting the modified region on the workpiece by focusing light onto it. Here, the formation of the modified region will be explained first.

[0062] like Figure 1The laser processing apparatus 100 shown is an example of a processing apparatus that performs laser processing using thermal stress. The laser processing apparatus 100 forms a modification region in the processing object 1 along a cutting intended line 5 by condensing laser light L in the processing object 1. The laser processing apparatus 100 includes a laser light source 101 that pulses the laser light L, a dichroic mirror 103 that is disposed so as to change the direction of the optical axis (optical path) of the laser light L by 90°, and a condensing lens 105 that condenses the laser light L. Further, the laser processing apparatus 100 includes a support table 107 that supports the processing object 1 on which the laser light L condensed by the condensing lens 105 is irradiated, a stage 111 that moves the support table 107, a laser light source control section 102 that controls the laser light source 101 in order to adjust the output, pulse width, pulse waveform, and the like of the laser light L, and a stage control section 115 that controls the movement of the stage 111.

[0063] In the laser processing apparatus 100, the laser light L emitted from the laser light source 101 has its optical axis changed in direction by 90° by the dichroic mirror 103 and is condensed inside the processing object 1 placed on the support table 107 by the condensing lens 105. At the same time, the stage 111 is moved so that the processing object 1 is moved relatively to the laser light L along the cutting intended line 5. Thus, a modification region along the cutting intended line 5 is formed in the processing object 1. Note that, in this case, the stage 111 is moved in order to move the laser light L relatively, but the condensing lens 105 can be moved instead, or both can be moved.

[0064] As the processing object 1, a plate-shaped member (e.g., a substrate, a wafer, or the like) including a semiconductor substrate formed of a semiconductor material and a piezoelectric substrate formed of a piezoelectric material, or the like is used. As shown in FIG. 1, the processing object 1 has a cutting intended line 5 for cutting the processing object 1. Figure 2 As shown in FIG. 1, the processing object 1 has a cutting intended line 5 for cutting the processing object 1. The cutting intended line 5 is a broken line extending in a straight line. In the case where a modification region is formed inside the processing object 1, as shown in FIG. 2, the cutting intended line 5 is a broken line extending in a straight line in the processing object 1. Figure 3 As shown in FIG. 1, the processing object 1 has a cutting intended line 5 for cutting the processing object 1. The cutting intended line 5 is a broken line extending in a straight line. In the case where a modification region is formed inside the processing object 1, as shown in FIG. 2, the cutting intended line 5 is a broken line extending in a straight line in the processing object 1. Figure 2 As shown in FIG. 1, the processing object 1 has a cutting intended line 5 for cutting the processing object 1. The cutting intended line 5 is a broken line extending in a straight line. In the case where a modification region is formed inside the processing object 1, as shown in FIG. 2, the cutting intended line 5 is a broken line extending in a straight line in the processing object 1. Figure 4 Figure 5 Figure 6 ​​As shown, the modified region 7 is formed in the work object 1 along the cutting intended line 5, and the modified region 7 formed along the cutting intended line 5 becomes a cutting starting point region 8. By applying an external force to the work object 1 in which the modified region 7 as the cutting starting point region 8 is formed, the work object 1 is divided into a plurality of pieces; or, when the modified region 7 as the cutting starting point region 8 is formed, the work object 1 can be divided into a plurality of pieces with the modified region 7 as a starting point of cutting.

[0065] The condensing point P is a site where the laser L is condensed. The cutting intended line 5 is not limited to a straight line, but can be a curved line, a three-dimensional shape formed by a combination of these, or a form in which coordinates are specified. The cutting intended line 5 is not limited to a virtual line, but can be a line actually drawn on the surface 3 of the work object 1. The cutting intended line 5 is a modified region formation intended line. The modified region formation intended line is an intended line in which the modified region 7 is intended to be formed. The modified region 7 can be formed continuously or discontinuously. The modified region 7 can be columnar or punctiform, and the point is that the modified region 7 is formed at least inside the work object 1. Also, there is a case where a crack is formed with the modified region 7 as a starting point, and the crack and the modified region 7 can be exposed to the outer surface (the surface 3, the back surface, or the peripheral surface) of the work object 1. The laser incidence surface at the time of formation of the modified region 7 is not limited to the surface 3 of the work object 1, but can be the back surface or the side surface of the work object 1.

[0066] On the surface 3 or the back surface side of the work object 1, a plurality of functional components (light receiving elements such as photodiodes, light emitting elements such as laser diodes, or circuit elements formed as circuits) are formed in a matrix shape. A plurality of cutting intended lines 5 are set in a lattice shape so as to pass between adjacent functional components.

[0067] It should be noted that, in a case where the modified region 7 is formed inside the work object 1, the laser L is transmitted through the work object 1 and is specifically absorbed near the condensing point P located inside the work object 1. Thus, the modified region 7 is formed in the work object 1 (i.e., internal absorption type laser processing). In this case, the laser L is hardly absorbed on the surface 3 of the work object 1, and thus the surface 3 of the work object 1 is not melted. On the other hand, in a case where the modified region 7 is formed on the surface 3 of the work object 1, the laser L is specifically absorbed near the condensing point P on the surface 3, is melted from the surface 3, and is removed, thereby forming a removal portion such as a hole or a groove (surface absorption type laser processing).

[0068] The modified region 7 refers to a region in which the density, the refractive index, the mechanical strength, or other physical characteristics become a state different from the surroundings thereof. As the modified region 7, for example, there are a fusion-processed region (indicating at least any one of a region after temporarily melting and solidifying again, a region in a molten state, and a region in a state of solidifying again after melting), a crack region, an insulation breakdown region, a refractive index variation region, and the like, and there are also regions in which these are mixed. Further, as the modified region 7, there are a region in which the density of the modified region 7 is changed compared with the density of the non-modified region in the material of the processing target object 1, and a region in which a crystal lattice defect is formed. In the case where the material of the processing target object 1 is a single crystal silicon, the modified region 7 can also be referred to as a high dislocation density region.

[0069] Further, in the case of the fusion-processed region, the refractive index variation region, the region in which the density of the modified region 7 is changed compared with the density of the non-modified region, and the region in which a crystal lattice defect is formed, there are cases in which a crack (a flaw, a micro crack) is contained in the inside of the region and on the interface between the modified region 7 and the non-modified region. In the case of the contained crack, there are cases in which the crack is formed across the entire surface of the modified region 7, and cases in which the crack is formed only in a part or a plurality of parts. The processing target object 1 includes a substrate composed of a crystalline material having a crystal structure. For example, the processing target object 1 includes a substrate formed of at least any one of gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO3, diamond, GaOx, and sapphire (Al2O3). In other words, in the processing target object 1, for example, there are a gallium nitride substrate, a silicon substrate, a SiC substrate, a LiTaO3 substrate, a diamond substrate, a GaOx substrate, or a sapphire substrate. As the crystalline material, there can be any one of an anisotropic crystal and an isotropic crystal. As the processing target object 1, there can also be a substrate composed of an amorphous material having an amorphous structure (an amorphous structure), for example, a glass substrate.

[0070] In the embodiment, the modified region 7 can be formed by forming one or a plurality of modified points (processing marks, modified layers). In this case, one modified point or a plurality of modified points concentrated become the modified region 7. The modified point is one or a plurality of modified portions included in the modified region 7. The modified point is a modified portion constituting the modified region 7. The modified point is a point-like modified portion. At least any one of the plurality of modified points can be either separated from each other or in contact with each other (continuous). The modified point is a modified portion formed by emission of one pulse of the pulsed laser (i.e., laser irradiation of one pulse: laser emission). Here, the modified point corresponds to a modified portion formed by irradiation of one pulse of the first laser described later. As the modified point, for example, a crack point, a melting processing point, or a refractive index change point, or a point in which at least one of these is mixed can be given. For the modified point, the size of the modified point and the length of the crack generated can be appropriately controlled in consideration of the required cutting accuracy, the required flatness of the cut surface, and the thickness, kind, crystal orientation, and the like of the work object 1. Also, in the embodiment, the modified point can be formed along the cutting intended line 5, and the modified point can be taken as the modified region 7. The modified point is not limited to be in a partial or point-like form. The size and shape of the modified point are not particularly limited, and can be various sizes and shapes.

[0071] [Formation mechanism of modified point]

[0072] The inventors found that, when the modified point is formed in the work object 1, there are phenomena having different specificities at each stage during the period from the start to the end thereof. Hereinafter, the formation mechanism of the modified point will be described.

[0073] As Figure 7 shown, for the phenomena from the start to the end of the formation of the modified point S, according to the contents of the phenomena, five stages can be divided. In this example, the work object 1 is silicon.

[0074] The first stage is a period immediately after the pulse of the laser L is irradiated on the work object 1. In the first stage, in the work object 1, initial absorption occurs from around room temperature, local temperature rise and plasma occur in a part of the region near the focal point (a region including a part of the focal point: hereinafter, sometimes simply referred to as "a part of the region"), and the absorptivity of the part of the region temporarily rises. The end of the first stage is, for example, a time point until 1 ps from the start of the irradiation of the laser L on the work object 1, in the case where a nonlinear absorption phenomenon such as multiphoton absorption occurs, that is, in the case of nonlinear absorption; or a time point until 1 ms, in the case where a normal absorption phenomenon, that is, linear absorption occurs. The work object 1 in the first stage has, for example, a temperature of several ten thousand K. The work object 1 in the first stage is in a state of plasma, vapor, or liquid. For such a first-stage laser L, any one of the following characteristics is desirable: good condensing property, transmissivity to the focal point, selective absorptivity in the focal point, high peak power, and steeply rising pulse waveform.

[0075] The second stage is a period in which the local temperature continues to rise and the part of the region in which the absorptivity rises expands. The second stage is a period of irradiation of the laser L. In the second stage, energy is injected into a part of the region in the work object 1 that is in a high-temperature state (a high-temperature region), the high-temperature region is expanded toward the upper side (the irradiation side of the laser L), and the formation region of the modified point is determined. The end of the second stage is, for example, a time point until 700 ns from the start of the irradiation of the laser L on the work object 1. The work object 1 in the second stage has, for example, a temperature of 2000 to 10000 K. The work object 1 in the second stage is in a liquid state. In the second stage, the high-temperature region is a molten region. For such a second-stage laser L, what is important is the pulse waveform thereof and the wavelength thereof that is not absorbed by the work object 1 before the work before the work object 1 around room temperature. For the second-stage laser L, any one of the following characteristics is desirable: a propagation profile corresponding to the work requirement (work purpose), large pulse energy, and long duration.

[0076] The third stage is a period during which the rapid temperature drop due to the conductive cooling continues, the cavities 13 are fixed, and the closing of the molten region (formation of the solidified region 11) occurs. The third stage is a period immediately after the irradiation of the laser L is stopped. The end of the third stage is, for example, a point in time up to 2 μs from the start of the irradiation of the laser L toward the workpiece 1. The workpiece 1 in the third stage has a temperature of, for example, 500 to 2000 K. The workpiece 1 in the third stage is in a solid state. In this third stage, any one of the following phenomena is expected to occur: rapid conductive cooling, early solidification around the focal point (fixing of the cavities 13), and closing of the molten liquid in a shape suitable for division and with a large volume. In addition, the fixing of the cavities 13 is not limited to formation in the third stage, but can also occur in the second stage.

[0077] The fourth stage is a period during which the entire body is solidified by further heat diffusion, a large stress St occurs in the region that is in a molten state until the end, a residual stress field is formed, and microcracks are generated and grown. In the illustrated example, the generated and grown microcracks gather together to form a microcrack group 9. The microcrack group 9 is a microcrack aggregate. The fourth stage is a period during which the irradiation of the laser L is stopped. A dislocation area is formed in the fourth stage. The end of the fourth stage is, for example, a point in time up to 10 μs from the start of the irradiation of the laser L toward the workpiece 1. The workpiece 1 in the fourth stage has a temperature equivalent to room temperature. The workpiece 1 in the fourth stage is in a solid state. In this fourth stage, at least any one of the following is expected: a solidification sequence and speed suitable for division, and formation of dislocations and a high-pressure region (control of the distribution of residual stress).

[0078] The fifth stage is a period during which the next pulse of the laser L is irradiated to the workpiece 1, as in the first stage. In addition, in the fifth stage, the microcracks grow in the modified points S formed in the first to fourth stages up to this point, and the microcrack group 9 is expanded.

[0079] Figure 8 is a photograph showing a cross section of the workpiece 1 after the formation of the modified points S. The state in the figure corresponds to the state in the fifth stage. The upper side in the figure is the irradiation side of the laser L. As Figure 8As shown, the modified particle S comprises a molten solidification region 11, a microcrack cluster 9, and a void 13. The molten solidification region 11 is the area that remains molten until the very end during the resolidification from the third to the fourth stage. Large stresses are generated due to the volume expansion during the resolidification of the molten solidification region 11. Cracks 14 are generated by the stress centered on the molten solidification region 11. The microcrack cluster 9 is formed along with the stress during the resolidification from the third to the fourth stage. High-density dislocations are also present in the microcrack cluster 9. The microcrack cluster 9 aggregates and grows to become crack 14. Voids 13 are cavities left during the resolidification after melting and evaporation in the second stage. The focal point P in the figure is the starting point of the processing and represents the area of ​​action in the first stage.

[0080] [First Implementation Method]

[0081] Next, the laser processing apparatus of the first embodiment will be described.

[0082] like Figure 9 The laser processing apparatus 200 of the first embodiment shown is a type of apparatus that prioritizes dividing force, which is capable of cutting the object 1 along the thickness direction with high dividing force. The laser processing apparatus 200 includes: a first light source 201, a second light source 202, a first attenuator 203, a second attenuator 204, a first beam expander 205, a second beam expander 206, a spatial light modulator 207, a relay optical system 208, a dichroic mirror 209, a focusing optical system 210, and a cylindrical lens unit 211.

[0083] The first light source 201 emits a first laser (first beam) L1, which is a pulsed laser with pulse oscillation. As an example, the first light source 201 emits a first laser L1 with a wavelength of 1064 nm and a pulse duration of 30 ns. The second light source 202 emits a second laser (second beam) L2, which is a pulsed laser with pulse oscillation. As an example, the second light source 202 emits a second laser L2 with a wavelength of 1550 nm and a pulse duration of 1000 ns. The first laser L1 and the second laser L2 correspond to the laser L mentioned above.

[0084] The first attenuator 203 adjusts the output (light intensity) and polarization direction of the first laser L1 emitted from the first light source 201. The second attenuator 204 adjusts the output and polarization direction of the second laser L2 emitted from the second light source 202. The first beam expander 205 adjusts the beam diameter and divergence angle of the first laser L1 passing through the first attenuator 203. The second beam expander 206 adjusts the beam diameter and divergence angle of the second laser L2 passing through the second attenuator 204.

[0085] The spatial light modulator 207 modulates and reflects the first laser light Ll that has passed through the first beam expander 205 and has been reflected by the mirror 212. The spatial light modulator 207 is a spatial light modulator (SLM) such as a reflective liquid crystal on silicon (LCOS). The spatial light modulator 207 has a display portion that receives the first laser light Ll, and modulates the reflected first laser light Ll (for example, modulates the intensity, amplitude, phase, polarization, and the like of the first laser light Ll) by appropriately setting a modulation pattern displayed on the display portion.

[0086] The relay optical system 208 images (forms an image of) the first laser light Ll in the display portion of the spatial light modulator 207 (the first laser light Ll after being modulated in the spatial light modulator 207) to the entrance pupil plane of the condensing optical system 210. As the relay optical system 208, for example, a 4f lens unit can be used.

[0087] The dichroic mirror 209 transmits the first laser light Ll that has passed through the relay optical system 208 and has been reflected by the mirror 213 to the condensing optical system 210, and reflects the second laser light L2 that has passed through the cylindrical lens unit 211 to the condensing optical system 210.

[0088] The condensing optical system 210 condenses the first laser light Ll and the second laser light L2 to the machining object 1. The condensing optical system 210 has a plurality of lenses and a holder that holds the plurality of lenses. The condensing optical system 210 is movable in the direction of the optical axis thereof by a driving force of a driving mechanism such as a piezoelectric element.

[0089] The cylindrical lens unit 211 adjusts (shapes) the beam profile of the second laser light L2 that has passed through the second beam expander 206 and has been reflected by the mirror 214 and the mirror 215. The cylindrical lens unit 211 adjusts the beam profile of the second laser light L2 that is irradiated to the machining object 1 to an elongated shape in the direction of the cutting intended line 5.

[0090] The control portion 216 is constituted by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The control portion 216 controls the operation of each portion of the laser processing apparatus 200. The control portion 216 has the above-described laser light source control portion 102 and the stage control portion 115 (refer to FIG. 1) as a function thereof. Figure 1The control section 216 controls the operation of the first light source 201 and the second light source 202, and causes the first laser light Ll and the second laser light L2 to be emitted from the first light source 201 and the second light source 202, respectively. The control section 216 adjusts the output and the pulse width of the first laser light Ll and the second laser light L2 emitted from the first light source 201 and the second light source 202. The control section 216 controls the operation of each part of the laser processing apparatus 200, and thereby causes the focal points of the first laser light Ll and the second laser light L2 to be located at a predetermined depth and relatively move along the cutting intended line 5 when the modified point S is formed. The control section 216 controls the time points at which the first laser light Ll and the second laser light L2 reach in the processing point by adjusting the time points at which the first laser light Ll and the second laser light L2 are emitted from the first light source 201 and the second light source 202.

[0091] The control section 216 controls the display section of the spatial light modulator 207 to display a predetermined modulation pattern when the modified point S is formed, and causes the spatial light modulator 207 to perform desired modulation on the first laser light Ll. The modulation pattern to be displayed is, for example, calculated in advance in accordance with the depth position of the modified point S to be formed, the wavelength of the first laser light Ll, the material of the processing target object 1, the refractive index of the condensing optical system 210 and the processing target object 1, and the like, and stored in the control section 216. The modulation pattern can include at least any one of an individual difference correction pattern for correcting individual differences occurring in the laser processing apparatus 200, a spherical aberration correction pattern for correcting spherical aberration, a coma correction pattern for correcting coma, and the like.

[0092] The control section 216 controls the second light source 202 to emit the second laser light L2 after the first light source 201 emits the first laser light Ll. Specifically, the control section 216 causes the first laser light Ll to be irradiated with one pulse toward the processing target object 1, and causes the second laser light L2 to be irradiated with one pulse toward a part of the region of the processing target object 1 during a period in which the absorbance of the part of the region temporarily increases, that is, an absorbance increase period. The control section 216 stops the emission of the first light source 201 and the second light source 202 for a certain period after the second laser light L2 is irradiated with one pulse. Thereafter, the control section 216 repeatedly performs the irradiation of the first laser light Ll and the second laser light L2 with one pulse.

[0093] The "part of the region" is, for example, the vicinity of the focal point of the first laser light Ll, and is a region in which the absorption rate rises in conjunction with the irradiation and condensation of the first laser light Ll. The "absorption rate" refers to the ratio of absorption of the first laser light Ll and the second laser light L2 per unit length (for example, per 1 cm). The "absorption rate rise period" refers to a period in which the absorption rate temporarily rises (temporarily becomes large) based on the absorption rate before the first laser light Ll is irradiated. With respect to the "absorption rate rise period", in a range in which the absorption rate is larger than before the first laser light Ll is irradiated, the period in which the absorption rate increases and the period in which the absorption rate decreases are included. For example, in the absorption rate rise period, in a range in which the absorption rate is larger than before the first laser light Ll is irradiated, the absorption rate first increases and then decreases with the passage of time.

[0094] More specifically, as described below, the control section 216 controls the irradiation timing of the first laser light Ll and the second laser light L2. That is, as shown in FIG. 6, first, one pulse of the first laser light Ll is irradiated. Thereby, the first stage is started, and the absorption rate of the part of the region sharply rises and then decreases after reaching a peak. During this absorption rate rise period H, one pulse of the second laser light L21 is irradiated. In the example shown in the figure, the pulse of the second laser light L2 rises at the end of the pulse of the first laser light Ll. The pulse of the second laser light L2 ends after continuing for a prescribed period. By the irradiation of the second laser light L2, the absorption rate is raised or maintained. In conjunction with the end thereof, the second stage ends, and the third stage is started. Also, the irradiation of the first laser light Ll and the second laser light L2 is stopped for a certain period. Thereby, the third stage and the fourth stage are continued. Figure 10

[0095] In the laser processing apparatus 200 configured in the manner described above, a processing method including the following steps is implemented, that is, a step of irradiating the first laser light Ll to the processing target 1 and temporarily raising the absorption rate in a part of the region of the processing target 1 before the first laser light Ll is irradiated, and a step of irradiating the second laser light L2 to the part of the region during the absorption rate rise period H in which the absorption rate of the part of the region temporarily rises.

[0096] Here, with respect to the laser processing apparatus 200, the characteristics of the first laser light Ll and the second laser light L2 that are irradiated to the processing target 1 are described in detail below.

[0097] ​The energy of the second laser L2 is higher than the energy of the first laser LI. Here, the "energy" is the total amount of energy input in the entire time axis. The peak intensity of the second laser L2 is lower than the peak intensity of the first laser LI. The "peak intensity" here refers to the energy per unit area and per unit time in the region where the laser L is absorbed. The energy and the peak intensity of the first laser LI can be controlled, for example, by at least any one of the first light source 201 and the first attenuator 203. The energy and the peak intensity of the second laser L2 can be controlled, for example, by at least any one of the second light source 202 and the second attenuator 204. The energy and the peak intensity of the first laser LI and the second laser L2 can also be controlled using a modulator such as an EOM (Electro-Optic Modulator) or an AOM (acousto-Optic Modulator).

[0098] The wavelength of the second laser L2 is different from the wavelength of the first laser LI. The wavelength of the second laser L2 and the wavelength of the second laser L2 are wavelengths that transmit the processing target object 1, and here, are 1000 to 8500 nm that transmit silicon. The wavelength of the second laser L2 is longer than the wavelength of the first laser LI. When the processing target object 1 is silicon, if the wavelength is set to 1000 nm or more and less than 1100 nm, the absorption to the processing target object 1 is rapid, the damage is less, and the crack is less likely to extend. When the processing target object 1 is silicon, if the wavelength is set to 1100 nm or more and less than 2000 nm, the separation force becomes high, and at this time, the separation force can be prioritized (the growth of the crack that occurs) compared to the suppression of the damage to the processing target object 1. When the processing target object 1 is silicon, if the wavelength is set to 2000 nm or more and less than 8500 nm, the separation force is higher, and at this time, the separation force can be more prioritized compared to the suppression of the damage to the processing target object 1. The wavelength of the first laser LI can be controlled, for example, by at least any one of the first light source 201 and the spatial light modulator 207. The wavelength of the second laser L2 can be controlled, for example, by the second light source 202. The wavelength of the first laser LI and the second laser L2 can also be controlled using a modulator such as an EOM or an AOM.

[0099] The second laser L2 is a laser that does not form the modified points S and the modified region 7 when irradiated alone toward the processing target 1. For example, the peak intensity of the second laser L2 is lower than the processing threshold of the processing target 1, and the formation of the modified points S does not start when irradiated alone. In this case, the second laser L2 can be irradiated to the processing target 1 at all times or in advance, and only the first laser L1 functions as a trigger to start processing. At this time, the second laser L2 does not become escape light by being absorbed by the processing target 1 until the start of processing. The "escape light" refers to light that is incident from one side of the processing target 1 and escapes (emerges) from the other side without being absorbed by the processing target 1. Damage that occurs on the side opposite the light incident side due to the escape light is also referred to as "back surface damage".

[0100] The NA (Numerical Aperture) of the second laser L2 is different from the NA of the first laser L1. The NA of the first laser L1 refers to the angle at which the first laser L1 converges at the converging position of the first laser L1. The NA of the second laser L2 refers to the angle at which the second laser L2 converges at the converging position of the second laser L2. Specifically, the NA of the second laser L2 is smaller than the NA of the first laser L1. The second laser L2 can also be a parallel light beam.

[0101] Regarding the NA of the first laser L1, for example, control can be performed by at least any one of the first beam expander 205, the spatial light modulator 207, and the converging optical system 210. Regarding the NA of the second laser L2, for example, control can be performed by at least any one of the second beam expander 206 and the converging optical system 210. In particular, regarding the NA of the laser L, control can be performed by at least any one of an objective lens or a limited opening such as a pinhole, a beam adjustment system such as a beam expander, and a spatial light modulator. The higher the value of the NA, the smaller the beam spot size of the converging point, and there is a tendency for the light beam diameter to increase rapidly away from the converging point. The NA depends on the diameter of the laser L in the converging optical system 210 and the focal distance of the converging optical system 210. The higher the NA, the greater the position dependence of the peak intensity of the laser L. In the case where the laser L is concentrated locally in the depth direction (the optical axis direction, the thickness direction), it is advantageous for the NA to be high. On the other hand, in the case where the laser L is distributed along the optical axis direction in a long region, it is advantageous for the NA to be low.

[0102] The beam profile of the second laser L2 differs from that of the first laser L1. Specifically, the beam profile of the first laser L1 is a circle or ring, exhibiting rotational symmetry. The beam profile of the second laser L2 is a long strip shape along the predetermined cutting line 5. The beam profile of the second laser L2 is a rotationally asymmetrical shape (e.g., oblong, elliptical, rectangular, or polygonal) with the direction along the predetermined cutting line 5 as its length direction. The beam profile of the first laser L1 can be controlled by the spatial light modulator 207. The beam profile of the second laser L2 can be controlled by the cylindrical lens unit 211. Alternatively, for example, a diffractive optical element (DOE) or a spatial light modulator can be used to control the beam profile, in which case even complex beam profiles such as oblong or polygonal shapes can be easily obtained.

[0103] The second laser L2's M 2 The value of M of the first laser L1 2 The values ​​are different. M 2 The value indicates the quality of laser L (the transverse mode of laser L). M 2 The value indicates the focusing ability of the laser beam L. M 2 The value is also represented as M^2. M 2 The value indicates how far the actual laser L is from the ideal Gaussian laser (fundamental mode light) of TEM00. M 2 The value is the ratio of the product of the divergence angle and the beam waist diameter of the actual laser L to the product of the divergence angle and the beam waist diameter of the Gaussian laser of TEM00.

[0104] The second laser L2's M 2 The value is M compared to the first laser L1 2 The value is large. For the first laser L1, good beam quality is essential; the M value of the first laser L1 is... 2 The value is below 1.5. For the second laser L2, it does not need to have the same beam quality as the first laser L1; the M value of the second laser L2... 2 The value is below 6.0. For the first laser L1, M... 2 The value, for example, can be controlled by at least one of the first light source 201 and the spatial light modulator 207. For the M value of the second laser L2... 2 The value, for example, can be controlled by the second light source 202. Additionally, for the M value of laser L... 2 The value can also be controlled by utilizing at least one of the laser source, spatial filter, and spatial light modulator of the laser L.

[0105] The pulse width of the second laser L2 is different from the pulse width of the first laser L1. The pulse width of the second laser L2 is longer than the pulse width of the first laser L1. The pulse width of the first laser L1 is controlled by the first light source 201, for example. The pulse width of the second laser L2 is controlled by the second light source 202, for example. The pulse width of the first laser L1 and the second laser L2 can also be controlled using a modulator such as an EOM or an AOM.

[0106] The pulse waveform of the second laser L2 is different from the pulse waveform of the first laser L1. The pulse waveform of the first laser L1 is a rectangular waveform or a Gaussian waveform. The pulse waveform of the second laser L2 is a waveform in which the output increases with time, specifically, a waveform in which the output increases in such a manner that the peak intensity becomes a certain value as the effective area of absorption of the second laser L2 in the absorption region increases (hereinafter, sometimes referred to as a "rear-rising waveform"). The pulse waveform of the second laser L2 is a square curve, for example. The pulse waveform of the first laser L1 is controlled by the first light source 201, for example. The pulse waveform of the second laser L2 is controlled by the second light source 202, for example. The pulse waveform of the first laser L1 and the second laser L2 can also be controlled using a modulator such as an EOM or an AOM.

[0107] The polarization direction of the second laser L2 is different from the polarization direction of the first laser L1. The polarization direction of the first laser L1 is vertical, horizontal, clockwise circular polarization, counterclockwise circular polarization, or Z polarization. The polarization direction of the second laser L2 is horizontal, vertical, counterclockwise circular polarization, clockwise circular polarization, or Z polarization. The polarization direction of the first laser L1 is controlled by at least either one of a wave plate (not shown) and a spatial light modulator 207, for example. The polarization direction of the second laser L2 is controlled by a wave plate (not shown), for example. As the polarization, linear polarization, crossed polarization, circular polarization, random polarization, Z polarization, and radial polarization can be cited, for example. The wave plate includes at least one of a 1 / 4 wave plate, a 1 / 2 wave plate, and a Z wave plate. The polarization direction of the first laser L1 and the second laser L2 can also be controlled using at least either one of a wave plate, a depolarizer, and a spatial light modulator.

[0108] According to this laser processing apparatus 200, the first laser L1 necessary and sufficient in the first stage can be supplied in the most suitable time and spatial distribution in the first stage. After the appropriate time interval, the second laser L2 necessary and sufficient in the second stage can be supplied in the most suitable time and spatial distribution in the second stage. Thereafter, after the third stage, the second laser L2 (and other light) is rapidly interrupted, so that cooling can be performed rapidly.

[0109] For the laser processing apparatus 200 herein, the first laser L1 and the second laser L2 that are irradiated to the processing target 1 have the following characteristics.

[0110] (Wavelength)

[0111] First laser L1: 1026 to 1064 nm

[0112] Second laser L2: 1180 to 7500 nm

[0113] (Beam quality (M 2 value)

[0114] First laser L1: 1.0

[0115] Second laser L2: less than 3.0

[0116] (Pulse duration)

[0117] First laser L1: 20 to 50 ns

[0118] Second laser L2: 0.7 to 5 μs

[0119] (Pulse rise time)

[0120] First laser L1: less than 5 ns

[0121] Second laser L2: less than 50 ns

[0122] (Pulse waveform)

[0123] First laser L1: rectangular waveform or Gaussian waveform

[0124] Second laser L2: rear rise waveform (quadratic curve)

[0125] (Peak intensity)

[0126] First laser L1: 70 W

[0127] Second laser L2: 150 to 250 W

[0128] (Repetition frequency)

[0129] First laser L1: 150 kHz or less

[0130] Second laser L2: 150 kHz or less

[0131] (Irradiation time point)

[0132] First laser L1: arbitrary

[0133] Second laser L2: after 20 to 30 ns

[0134] (first laser L1)

[0135] (converging system)

[0136] first laser L1: converging priority

[0137] second laser L2: path priority

[0138] (aberration correction)

[0139] first laser L1: yes

[0140] second laser L2: no

[0141] (symmetry of beam profile)

[0142] first laser L1: rotational symmetry (circular)

[0143] second laser L2: elongated in the direction of the cutting intended line 5

[0144] (NA)

[0145] first laser L1: 0.7 or more

[0146] second laser L2: 0.2 to 0.6

[0147] In the laser processing apparatus 200, the energy of the second laser L2 is higher than the energy of the first laser L1. Thereby, the first laser L1 and the second laser L2 can be further irradiated in correspondence with each phenomenon of the first stage and the second stage.

[0148] In the laser processing apparatus 200, the peak intensity of the second laser L2 is lower than the peak intensity of the first laser L1. Thereby, the first laser L1 and the second laser L2 can be further irradiated in correspondence with each phenomenon of the first stage and the second stage.

[0149] In the laser processing apparatus 200, the peak intensity of the second laser L2 is lower than the peak intensity of the first laser L1. Thereby, the first laser L1 and the second laser L2 can be further irradiated in correspondence with each phenomenon of the first stage and the second stage.

[0150] In the laser processing apparatus 200, the wavelength of the second laser L2 is different from the wavelength of the first laser L1. By making the wavelength of the first laser L1 and the wavelength of the second laser L2 appropriately different, the absorption of the first laser L1 and the second laser L2 in the processing target object 1 and the processing result can be controlled. Further, since the light absorption characteristic of the semiconductor, that is, the processing target object 1, greatly changes near the band gap, by changing the wavelength, the absorption distribution and the processing result can be effectively controlled. In particular, in the laser processing apparatus 200, the wavelength of the second laser L2 is longer than the wavelength of the first laser L1. Thereby, the absorption of the first laser L1 can be accelerated and damage can be suppressed, and the separation force can be increased by the second laser L2 (high separation force and suppression of damage are simultaneously achieved).

[0151] In the laser processing apparatus 200, the second laser L2 is light that does not form a modified point S when irradiated alone to the processing target object 1. Thereby, it is also possible to irradiate the second laser L2 at all times or in advance, and even in this case, a modified point S is not formed, and the first laser L1 functions as a trigger to start the formation of the modified point S. Thus, it is not necessary to precisely control the irradiation timing of the second laser L2.

[0152] In the laser processing apparatus 200, the NA of the second laser L2 is different from the NA of the first laser L1. By making the NA of the first laser L1 and the NA of the second laser L2 appropriately different, the width of the processing region can be controlled. In particular, in the laser processing apparatus 200, the NA of the second laser L2 is smaller than the NA of the first laser L1. Thereby, even at a position away from the focal point, the divergence of the light beam of the second laser L2 is suppressed, so that the modified point S can be guided to or formed at a position away from the focal point.

[0153] In the laser processing apparatus 200, the beam profile of the second laser L2 is different from the beam profile of the first laser L1. By making the beam profile of the first laser L1 and the beam profile of the second laser L2 appropriately different, the separation force and the damage to the processing target object 1 can be controlled. In particular, in the laser processing apparatus 200, the beam profile of the first laser L1 is a rotationally symmetrical shape, whereby the first laser L1 can be condensed to a small region, and a high power density can be achieved. Thus, the first stage phenomenon can be achieved with a minimum amount of light leakage. The beam profile of the second laser L2 is a long strip shape along the cutting intended line 5. Thereby, the processing target object 1 can be easily cut along the cutting intended line 5. Also, when viewed in the thickness direction, the direction that is perpendicular to the cutting intended line 5 is the width direction of the beam profile of the second laser L2, so that the negative effects on the functional elements of the processing target object 1 by the second laser L2 can be suppressed.

[0154] In the laser processing apparatus 200, the M2 value of the first laser L1 is different from the M 2 value of the first laser L1 is different from the M 2 value of the second laser L2. By making the M 2 value of the first laser L1 different from the M 2 value of the second laser L2, simplification, low cost, and ease of use of the apparatus can be achieved. In particular, in the laser processing apparatus 200, the M 2 value of the first laser L1 is smaller than the M 2 value of the second laser L2. Thereby, the beam quality necessary for the first laser L1 can be ensured, and the restriction on the beam quality of the second laser L2 can be reduced.

[0155] In the laser processing apparatus 200, the pulse width of the second laser L2 is different from the pulse width of the first light. By making the pulse width of the first laser L1 different from the pulse width of the second laser L2, the first laser L1 and the second laser L2 can be further irradiated in correspondence with each phenomenon of the first stage and the second stage. In particular, in the laser processing apparatus 200, the pulse width of the first laser L1 is longer than the pulse width of the second laser L2. Thereby, the energy supply by the second laser L2 can be further appropriately performed in correspondence with the speed at which the molten region can grow, or in correspondence with the time necessary for the molten region to grow, and a more appropriate molten region and a modified point S can be formed.

[0156] In the laser processing apparatus 200, the pulse waveform of the second laser L2 is different from the pulse waveform of the first laser L1. By making the pulse waveform of the first laser L1 different from the pulse waveform of the second laser L2, the first laser L1 and the second laser L2 can be further irradiated in correspondence with each phenomenon of the first stage and the second stage. In particular, in the laser processing apparatus 200, the pulse waveform of the first laser L1 is a rectangular waveform or a Gaussian waveform, whereby the pulse waveform has a characteristic of rapid rise, and the light leakage before processing can be minimized. The pulse waveform of the second laser L2 is a rear rise waveform, whereby even in a case where the area of the absorption region of the second laser L2 increases, the peak intensity can be correspondingly maintained at a certain value.

[0157] In the laser processing apparatus 200, the polarization direction of the second laser L2 is different from that of the first laser L1. By appropriately differentiating the polarization directions of the first laser L1 and the second laser L2, the first laser L1 and the second laser L2 can be irradiated in accordance with the various phenomena of the first and second stages. The combination and separation of the first laser L1 and the second laser L2 become easier. In particular, in the laser processing apparatus 200, the polarization direction of the first laser L1 is vertical, horizontal, clockwise circularly polarized, counterclockwise circularly polarized, or Z-polarized, and the polarization direction of the second laser L2 is horizontal, vertical, counterclockwise circularly polarized, clockwise circularly polarized, or Z-polarized. Thus, even when the wavelengths of the first laser L1 and the second laser L2 are the same, the difference in polarization direction makes it easy to combine or separate beams pointing towards the same optical path. Furthermore, by using a Z-polarized laser L with high transmittance into the material, the internal processing of the object 1 can be performed more appropriately.

[0158] In the laser processing apparatus 200, the modified region 7 is the starting point region for cutting the workpiece 1 along the thickness direction. Therefore, the modified region 7 can be used as the starting point for cutting to cut (segment) the workpiece 1 along the thickness direction.

[0159] The laser processing apparatus 200 includes a first light source 201, a second light source 202, and a control unit 216. The laser processing apparatus 200 can be configured to irradiate a first laser L1 and a second laser L2 onto a workpiece 1 using the first light source 201 and the second light source 202 (multiple light sources).

[0160] In the laser processing apparatus 200, the irradiation direction of the second laser L2 toward the workpiece 1 is the same as the irradiation direction of the first laser L1 toward the workpiece 1. In this case, the first laser L1 and the second laser L2 can be irradiated from the same direction, and an optical system can be easily formed.

[0161] Further, the irradiation direction of the first laser light Ll and the irradiation direction of the second laser light L2 can be appropriately set according to the processing purpose and the restriction of the device structure. The focal point of the first laser light Ll and the focal point of the second laser light L2 can be the same or different, and by controlling the irradiation direction (propagation direction) of each of them, the processing can be characterized. For example, as shown in the modified example described later, the first laser light Ll can be made to be normally incident from the surface (or the back surface) of the processing target object 1, and on the other hand, the second laser light L2 can be made to be incident from the back surface (or the surface), from the side, from the opposite direction thereof, or from a direction in which these are combined. By appropriately setting the irradiation direction of the first laser light Ll, the direction of the initial light leakage can be controlled. By appropriately setting the irradiation direction of the second laser light L2, the following can be achieved: the direction of the separation force can be given, the formation direction and position of the modified point S can be controlled, or it can be made to be most suitable for a specific processing method (for example, distribution control of the remaining light leakage), and the like.

[0162] In the laser processing device 200, as described above, the second laser light L2 is supplied in a beam shape that is rotationally asymmetric in a long strip along the cutting intended line 5, with a large energy and a long duration. Thereby, the second stage is continued for a long time, and the molten solidification region 11 can be enlarged toward the extension direction of the cutting intended line 5.

[0163] Further, in the present embodiment, the various parameters of the first laser light Ll and the second laser light L2 are not limited to the above-described values. The wavelength of the first laser light Ll can also be 1000 nm to 1100 nm, and in particular, if it is 1026 nm, 1028 nm, 1030 nm, 1047 nm, 1064 nm, or 1080 nm, the device is easy to manufacture, and thus is effective. The wavelength of the first laser light Ll can also be 9500 nm to 10000 nm.

[0164] Regarding the condensing state of the first laser light Ll, in order to achieve a high condensing intensity and to be a good beam quality, M 2 The value can also be less than 1.2. Regarding the spherical aberration correction of the first laser light Ll, the condensing can also be performed without aberration in the focal point P. The focal point diameter (beam diameter of the focal point) of the first laser light Ll can also be φ1 μm or less. The pulse duration of the first laser light Ll can also be less than 30 to 50 ns.

[0165] The timing of irradiation of the second laser L2 (from the delay time of the first laser LI) is after the onset of the transition phenomenon of excitation of electrons or temperature rise or the like in the local part of the portion of the region generated by the irradiation of the first laser LI, and can be a timing earlier than the "timing at which the transition phenomenon ends or decays due to relaxation of the excited electrons or heat diffusion, so that the carriers or the like diffuse or disappear." The wavelength of the second laser L2 can also be 1150 nm to 9500 nm. The wavelength of the second laser L2 can be any wavelength that is transmittable through the work object 1. The requirement for the beam quality of the second laser L2 is greatly reduced, and for example, the M 2 value of the second laser L2 can also be 4. The focal point diameter (beam diameter of the focal point) of the second laser L2 can also be φ 3 μm or so. The pulse waveform of the second laser L2 can be any waveform as long as the rise thereof does not relax the temperature rise in the local part of the portion of the region generated by the irradiation of the first laser LI to the extent that the carriers or the like diffuse or disappear. The pulse rise time of the second laser L2 can also be 10 to 30 ns.

[0166] The pulse duration of the second laser L2 can also be 500 to 5000 ns. The polarization state of the second laser L2 can be any state. As the second light source 202, a cheap random polarization laser light source can also be used. The condensing state of the second laser L2 determines the machining performance, and thus can be set according to the machining requirements. For the second laser L2, it is not the focal point but the propagation state that is important compared to the first laser LI.

[0167] In the above-described structure, the first light source 201 and the control section 216 constitute the first irradiation section, and the second light source 202 and the control section 216 constitute the second irradiation section.

[0168] Figure 11 is a schematic diagram showing the structure of a laser machining device 220 of a first modification of the first embodiment. The laser machining device 220 of the first modification differs from the above-described laser machining device 200 (refer to Figure 9 ) in that the former further irradiates the second laser L2 in a manner opposite to the first laser LI. The laser machining device 220 further has a half mirror 221 and a condensing optical system 224 compared to the laser machining device 200.

[0169] The half mirror 221 is disposed between the cylindrical lens unit 211 and the dichroic mirror 209 in the optical path of the second laser L2. The half mirror 221 reflects a part of the second laser L2 that has passed through the cylindrical lens unit 211, and transmits the other part of the second laser L2.

[0170] The condensing optical system 224 condenses the second laser light L2 reflected by the half mirror 221 and reflected by the mirrors 222, 223 toward the work 1. The condensing optical system 224 is disposed so as to face the condensing optical system 210 across the work 1. The condensing optical system 224 has a back surface (or a surface) on the opposite side of the laser light incident surface, that is, the surface (or the back surface) of the condensing optical system 210 as a laser light incident surface, and the second laser light L2 is incident thereon. The condensing optical system 224 has the same structure as the condensing optical system 210. As the condensing optical system 224, an optical system having higher performance than the condensing optical system 210 need not be used. In the laser processing apparatus 220, the second laser light L2 is simultaneously irradiated toward the work 1 from the surface side and the back surface side, and the modified points S can be grown toward the surface side and the back surface side, respectively, and formed.

[0171] In the laser processing apparatus 220, the same effects as those of the laser processing apparatus 200 described above can be achieved. In the laser processing apparatus 220, the irradiation direction of one of the two second laser lights L2 is different from the irradiation direction of the first laser light L1. By appropriately making the irradiation directions of the first laser light L1 and the second laser light L2 different from each other, the direction in which the modified points S and the cracks are grown (can be selectively induced) and the positions of the modified points S and the cracks can be controlled. In the laser processing apparatus 220, the simultaneous growth of the modified points S from the surface side and the back surface side and the maximization of the separation force can be achieved by the opposing condensing optical systems 210, 224.

[0172] Figure 12 is a schematic view showing the structure of a laser processing apparatus 230 according to a second modification of the first embodiment. The laser processing apparatus 230 according to the second modification differs from the laser processing apparatus 200 (refer to Figure 9 ) described above in that the former has a beam shifter 231.

[0173] The beam shifter 231 is disposed between the cylindrical lens unit 211 and the dichroic mirror 209 on the optical path of the second laser light L2. The beam shifter 231 shifts the position of the second laser light L2. Specifically, the beam shifter 231 shifts the position of the second laser light L2 so that the irradiation direction (optical axis) of the second laser light L2 condensed by the condensing optical system 210 becomes an inclined direction inclined with respect to the optical axis of the condensing optical system 210. The inclined direction herein is a direction inclined from the front side toward the back side of the scanning direction of the laser light L (the first laser light L1 and the second laser light L2) as it approaches the work 1.

[0174] In addition, the beam shifter 231 is not particularly limited, and various optical elements can be used as long as the position of the second laser L2 can be shifted. Hereinafter, the advancing direction of the scan will be simply referred to as the "scan advancing direction". The scan advancing direction is the direction in which the laser L is scanned, and is the direction in which the processing is performed.

[0175] In the laser processing apparatus 230, the above-described effects of the laser processing apparatus 200 can be achieved. In the laser processing apparatus 230, the second laser L2 can be irradiated from a tilt direction that is tilted with respect to the optical axis of the condensing optical system 210. In particular, the tilt direction is a direction that is tilted from the front side to the rear side of the scan advancing direction as the processing target object 1 is approached, and thus the modified point S can be formed before the laser L is scanned.

[0176] Figure 13 is a schematic diagram showing the structure of a laser processing apparatus 240 according to a third modification of the first embodiment. The laser processing apparatus 240 according to the third modification is different from the laser processing apparatus 200 (refer to FIG. 1) described above in that the former irradiates the second laser L2 from the side of the processing target object 1 and irradiates the second laser L2 in a manner opposite to the first laser L1. The laser processing apparatus 220 does not have the dichroic mirror 209 compared to the laser processing apparatus 200, and further has a half mirror 241 and condensing optical systems 242 and 243. In the laser processing apparatus 220, the condensing optical system 210 condenses only the first laser L1 to the processing target object 1. Figure 9

[0177] The half mirror 241 is disposed on the downstream side of the cylindrical lens unit 211 on the optical path of the second laser L2. The half mirror 241 reflects a part of the second laser L2 reflected by the mirror 244 through the cylindrical lens unit 211, and transmits the other part of the second laser L2.

[0178] ​The condensing optical system 242 condenses the second laser light L2 reflected by the half mirror 241 toward the machining object 1. The condensing optical system 242 is disposed opposite to the side surface of the machining object 1. The condensing optical system 242 enters the second laser light L2 toward the side surface of the machining object 1 as a laser light incident surface. The condensing optical system 242 has the same structure as the condensing optical system 210. The condensing optical system 243 condenses the second laser light L2 transmitted through the half mirror 221 and reflected by the mirrors 245 and 246 toward the machining object 1. The condensing optical system 243 is disposed opposite to the condensing optical system 210 with the machining object 1 interposed therebetween. The condensing optical system 243 enters the second laser light L2 toward the back surface (or the surface) opposite to the laser light incident surface, that is, the surface (or the back surface) of the condensing optical system 210. The condensing optical system 243 has the same structure as the condensing optical system 210. As the condensing optical systems 242 and 243, optical systems having higher performance than the condensing optical system 210 need not be used.

[0179] In the laser processing apparatus 240, the second laser light L2 is simultaneously irradiated toward the machining object 1 from the side surface side and the opposite side of the irradiation direction of the first laser light Ll, and the modified points S can be grown toward the side surface side and the opposite side of the irradiation direction of the first laser light Ll, respectively.

[0180] In the laser processing apparatus 240, the second laser light L2 is simultaneously irradiated toward the machining object 1 from the side surface side and the opposite side of the irradiation direction of the first laser light Ll, and the modified points S can be grown toward the side surface side and the opposite side of the irradiation direction of the first laser light Ll, respectively.

[0181] [Second Embodiment]

[0182] Next, the laser processing apparatus of the second embodiment will be described. Hereinafter, points different from the first embodiment will be described, and the repeated description will be omitted.

[0183] As Figure 14The laser processing apparatus 300 of the second embodiment shown is one in which damage to the work 1 is given priority in being suppressed, and is capable of suppressing damage (particularly, back surface damage) to the work 1 and cutting the work 1 along the thickness direction. The laser processing apparatus 300 differs from the laser processing apparatus 200 described above in the point that the former does not have the cylindrical lens unit 211. The laser processing apparatus 300 does not have the cylindrical lens unit 211, and makes both the first laser LI and the second laser L2 rotationally symmetrical beam profiles, and further unifies the propagation paths and focal points of both. Thus, the second laser L2 can more efficiently act on a portion of the region whose absorption temporarily rises by the first laser LI.

[0184] In the laser processing apparatus 300, priority is given to suppressing the light leakage of the first laser LI. The first laser LI has a large wavelength that can be absorbed by the work 1 and a sharply rising waveform. According to such a first laser LI, only the first stage can be implemented with a minimum amount of light leakage. In the laser processing apparatus 300, the second laser L2 has the following characteristics: a wavelength close to or longer than the energy band gap of the work 1, a rotationally symmetrical beam profile, a large energy, a sharply rising pulse waveform, and a long pulse duration. Thus, in a portion of the region whose absorption temporarily rises by the irradiation of the first laser LI, the second laser L2 can be irradiated in a manner unified in time and space, the second stage can be continued, and the molten solidified region 11 can be enlarged.

[0185] The laser processing apparatus 300 herein is configured such that the first laser LI and the second laser L2 that are irradiated to the work 1 have the following characteristics.

[0186] (wavelength)

[0187] First laser LI: 1026 to 1064 nm

[0188] Second laser L2: 1120 to 2000 nm

[0189] (brightness (M 2 value)

[0190] First laser LI: 1.0

[0191] Second laser L2: less than 3.0

[0192] (pulse duration)

[0193] First laser LI: 10 to 30 ns

[0194] Second laser L2: 0.5 to 1 μs

[0195] (Pulse rise time)

[0196] First laser L1: less than 3 ns

[0197] Second laser L2: less than 50 ns

[0198] (Pulse waveform)

[0199] First laser L1: rectangular waveform or Gaussian waveform

[0200] Second laser L2: rear rise waveform (quadratic curve)

[0201] (Peak intensity)

[0202] First laser L1: 70 W

[0203] Second laser L2: 150 to 250 W

[0204] (Repetition frequency)

[0205] First laser L1: 300 kHz or less

[0206] Second laser L2: 300 kHz or less

[0207] (Irradiation time point)

[0208] First laser L1: arbitrary

[0209] Second laser L2: 15 to 20 ns later

[0210] (Taking the start of irradiation of the first laser L1 as the starting point)

[0211] (Optimized appropriately according to the pulse width of the first laser L1, the rise of the first laser L1, and the rise of the second laser L2)

[0212] (Focusing system)

[0213] First laser L1: focusing priority

[0214] Second laser L2: path priority

[0215] (Aberration correction)

[0216] First laser L1: yes

[0217] Second laser L2: no

[0218] (Symmetry of beam profile)

[0219] First laser L1: rotational symmetry (circular)

[0220] Second laser L2: rotational symmetry (circular)

[0221] (NA)

[0222] First laser L1: 0.7 or more

[0223] Second laser L2: 0.2 to 0.6

[0224] In the laser processing apparatus 300 as well, the above-described effects produced by the laser processing apparatus 200 can be achieved. In the laser processing apparatus 300, in particular, the simple and inexpensive optical system can suppress the escape light and the damage to the processing target 1.

[0225] Figure 15 is a schematic diagram showing the structure of a laser processing apparatus 320 which is a modification of the second embodiment. The laser processing apparatus 320 of the modification differs from the above-described laser processing apparatus 300 (refer to Figure 14 ) in that the former irradiates the second laser L2 in opposition to the first laser L1. The laser processing apparatus 320 does not have the dichroic mirror 209 compared to the laser processing apparatus 300, and further has a condensing optical system 321. In the laser processing apparatus 320, the condensing optical system 210 condenses only the first laser L1 to the processing target 1.

[0226] The condensing optical system 321 condenses the second laser L2, which has passed through the second beam expander 206 and has been reflected by the mirrors 214, 215, 322, 323, 324, to the processing target 1. The condensing optical system 321 is arranged in opposition to the condensing optical system 210 with the processing target 1 interposed therebetween. The condensing optical system 321 has a back surface (or a surface) on the opposite side of the laser-incident surface, that is, the surface (or the back surface) of the condensing optical system 210 as a laser-incident surface, and the second laser L2 is incident thereon. The condensing optical system 321 has the same structure as the condensing optical system 210. As the condensing optical system 321, an optical system having higher performance than the condensing optical system 210 need not be used.

[0227] In this laser processing apparatus 320, the second laser L2 is irradiated to the processing target 1 from the opposite side of the irradiation direction of the first laser L1, and the modified points S are grown toward the opposite side of the irradiation direction of the first laser L1 and formed.

[0228] In the laser processing apparatus 320, the above-described effects of the laser processing apparatus 300 can be achieved. In the laser processing apparatus 320, by irradiating the second laser L2 from the opposite side of the irradiation direction of the first laser L1, the direction in which the modified point S and the crack are expanded can be controlled (selectively induced) toward the opposite side of the irradiation direction of the first laser L1 when the modified point S is formed. By irradiating the second laser L2 from the opposite side of the irradiation direction of the first laser L1, backside damage caused by escape light can be fundamentally avoided.

[0229] [Third Embodiment]

[0230] Next, the laser processing apparatus of the third embodiment will be described. Hereinafter, points different from the first embodiment will be described, and the repeated description will be omitted.

[0231] Figure 16 The laser processing apparatus 400 of the third embodiment illustrated above can form a modified point S elongated in the thickness direction in the processing target object 1. The laser processing apparatus 400 differs from the above-described laser processing apparatus 200 (refer to FIG. 2) in the device structure in that the former does not have the cylindrical lens unit 211. The laser processing apparatus 400 does not have the cylindrical lens unit 211, and makes both the first laser L1 and the second laser L2 into a rotationally symmetrical beam profile, and makes the propagation paths and the focal points of both further coincide. Thereby, the second laser L2 can more efficiently act on a part of the region in which the absorption rate is temporarily increased by the first laser L1. Figure 9

[0232] The laser processing apparatus 400 here is configured such that the first laser L1 and the second laser L2 irradiated to the processing target object 1 have the following features.

[0233] (Wavelength)

[0234] First laser L1: 1026 to 1064 nm

[0235] Second laser L2: 1120 to 2000 nm

[0236] (Beam quality (M 2 value))

[0237] First laser L1: 1.0

[0238] Second laser L2: less than 2.0

[0239] (Pulse duration)

[0240] First laser L1: 20 to 80 ns

[0241] ​Second laser L2: 2 to 200 μs

[0242] (Pulse rise time)

[0243] First laser LI: less than 3 ns

[0244] Second laser L2: less than 50 ns

[0245] (Pulse waveform)

[0246] First laser LI: rectangular waveform or Gaussian waveform

[0247] Second laser L2: rear rise waveform (quadratic curve) or rectangular waveform

[0248] (Peak intensity)

[0249] First laser LI: 70 W

[0250] Second laser L2: 150 to 250 W

[0251] (Repetition frequency)

[0252] First laser LI: 300 kHz or less

[0253] Second laser L2: 300 kHz or less

[0254] (Irradiation time point)

[0255] First laser LI: arbitrary

[0256] Second laser L2: 15 to 20 ns later

[0257] (Taking the start of irradiation of the first laser LI as the starting point)

[0258] (Collecting system)

[0259] First laser LI: collecting priority

[0260] Second laser L2: path priority

[0261] (Aberration correction)

[0262] First laser LI: yes

[0263] Second laser L2: no

[0264] (Symmetry of beam profile)

[0265] First laser LI: rotational symmetry (circular)

[0266] Second laser L2: rotational symmetry (circular) or arbitrary shape cross section

[0267] (NA)

[0268] First laser L1: 0.7 or more

[0269] Second laser L2: 0.4 to 0.6.

[0270] In the laser processing apparatus 400 as well, the above-described effects produced by the laser processing apparatus 200 can be achieved. In particular, in the laser processing apparatus 400, it is possible to form the modified points S and the modified region 7 elongated in the thickness direction.

[0271] Figure 17 is a schematic diagram showing the structure of a laser processing apparatus 420 according to a modification of the third embodiment. The laser processing apparatus 420 according to the modification differs from the above-described laser processing apparatus 400 (refer to Figure 16 ) in that the former further includes a cylindrical lens unit 421 and a beam displacer 422 between the mirror 215 and the dichroic mirror 209 in the optical path of the second laser L2.

[0272] The cylindrical lens unit 421 has the same structure as the above-described cylindrical lens unit 211 (refer to Figure 9 ). The beam displacer 422 has the same structure as the above-described beam displacer 231 (refer to Figure 12 ). In this laser processing apparatus 420, it is possible to irradiate the second laser L2 to the processing object 1 in the form of parallel beams.

[0273] In the laser processing apparatus 420 as well, the above-described effects produced by the laser processing apparatus 400 can be achieved. In addition, in the laser processing apparatus 420, by irradiating the second laser L2 to the processing object 1 in the form of parallel beams, it is possible to form the modified points S of infinite length on the side of the entrance surface of the second laser L2.

[0274] [Fourth Embodiment]

[0275] Next, the laser processing apparatus according to the fourth embodiment will be described. Hereinafter, points different from the first embodiment will be described, and the repeated description will be omitted.

[0276] Figure 18 The laser processing apparatus 500 according to the fourth embodiment shown in the drawing can cut the processing object 1 regardless of the cleaving direction of the processing object 1. The laser processing apparatus 500 differs from the above-described laser processing apparatus 200 (refer to Figure 9 ) in that the former further includes a beam displacer 501 and a beam shaper 502.

[0277] The beam shifter 501 moves the position of the second laser light L2. Specifically, the beam shifter 501 moves the position of the second laser light L2 so that the irradiation direction of the second laser light L2 condensed by the condensing optical system 210 becomes an inclined direction inclined with respect to the optical axis of the condensing optical system 210. The inclined direction here is a direction inclined from the back side to the front side of the scan travel direction as approaching the work object 1. Note that the beam shifter 501 is not particularly limited, and various optical elements can be used as long as the position of the second laser light L2 can be moved.

[0278] The beam shaper 502 shapes the beam profile of the second laser light L2 into an asymmetric profile that is asymmetric in the scan travel direction. As a specific example, the beam shaper 502 shapes the beam profile of the second laser light L2 as follows: that is, the second laser light L2 condensed by the condensing optical system 210 becomes a semicircular (semicircle of the back side in the scan travel direction) beam profile that is deficient on the front side in the scan travel direction.

[0279] In the above, in the laser processing apparatus 500, the above-described effects produced by the laser processing apparatus 200 can also be achieved. In particular, in the laser processing apparatus 500, it is possible to suppress cracking on the front side in the scan travel direction, and it is possible to cause cracking on the back side in the scan travel direction. It is possible to cut the work object 1 along the cutting intended line 5 without depending on the cleaving direction of the work object 1.

[0280] [Fifth Embodiment]

[0281] Next, the laser processing apparatus of the fifth embodiment will be described. Hereinafter, points different from the first embodiment will be described, and repeated descriptions will be omitted.

[0282] Figure 19 The laser processing apparatus 600 of the fifth embodiment shown can form the modified points S elongated in the thickness direction in the work object 1 without depending on the crystal orientation. The laser processing apparatus 600 differs from the above-described laser processing apparatus 200 (refer to Figure 9 ) in that the former further has a beam shifter 602 between the cylindrical lens unit 211 and the dichroic mirror 209 on the optical path of the second laser light L2. The cleaving direction of the work object 1 of the present embodiment is not along the extension direction of the cutting intended line 5, but intersects the cutting intended line 5.

[0283] The beam shifter 602 differs from the above-described beam shifter 231 (refer to Figure 12The structure is the same as that of the laser processing apparatus 600. In this laser processing apparatus 600, the second laser L2 can be irradiated onto the workpiece 1 in a parallel beam manner. The control unit 216 of this embodiment controls the irradiation time of the second laser L2 to control the solidification rate of the molten solidification region 11 in a way that does not cause cracking.

[0284] In the laser processing apparatus 600, the effects described above, produced by the laser processing apparatus 200, can also be achieved. In particular, in the laser processing apparatus 600, the second laser L2 is irradiated onto the workpiece 1 in a parallel beam manner, thereby suppressing cracking in the cracking direction while forming elongated modified particles S in the thickness direction.

[0285] [Sixth Implementation Method]

[0286] Next, the laser processing apparatus of the sixth embodiment will be described. Hereinafter, the differences from the first embodiment will be described, and repeated descriptions will be omitted.

[0287] for Figure 20 The laser processing apparatus 700 of the sixth embodiment shown can be constructed using inexpensive equipment. The laser processing apparatus 700 and the laser processing apparatus 200 described above (see...) Figure 9 The difference in the device structure is that the former does not have a second attenuator 204 and a cylindrical lens unit 601, but has a first light source 701 to replace the first light source 201 and a second light source 702 to replace the second light source 202.

[0288] The first light source 701 is different from the first light source 201 (refer to...). Figure 9 The second light source 702 is a small light source that outputs light. It utilizes a laser diode, a CW (Continuous Wave) fiber laser, or a QCW (Quasi Continuous Wave) fiber laser. As an example, the second light source 702 emits a second laser L2 with a wavelength of 1064 nm and a pulse duration of 1 μs.

[0289] In the laser processing apparatus 700, the effects produced by the laser processing apparatus 200 can also be achieved. In particular, the laser processing apparatus 700 provides a very inexpensive processing solution.

[0290] [Seventh Implementation Method]

[0291] Next, the laser processing apparatus of the seventh embodiment will be described. Hereinafter, the differences from the first embodiment will be described, and repeated descriptions will be omitted.

[0292] Figure 21The laser processing apparatus 800 of the seventh embodiment shown is capable of cutting (slicing) the processing target object 1 in a direction intersecting perpendicularly to the thickness direction (crossing). In the laser processing apparatus 800, the laser L (the first laser LI and the second laser L2) is incident from a direction intersecting perpendicularly to the slice predetermined surface provided in the processing target object 1, and a planar modified region 7 along the slice predetermined surface is formed inside the processing target object 1. The modified region 7 of the present embodiment is a cutting start point region of slicing.

[0293] The slice predetermined surface is an imaginary surface for slicing the processing target object 1, and expands in a planar shape. The slice predetermined surface is not limited to a planar shape, and can be a curved surface shape, can be a three-dimensional shape by a combination of these, or can be a shape whose coordinates are specified. The slice predetermined surface is a modified region formation predetermined surface. The modified region formation predetermined surface is a predetermined surface in which the modified region 7 is to be formed.

[0294] The laser processing apparatus 800 differs from the above-described laser processing apparatus 200 (refer to Figure 9 ) in the device structure in that the former further includes a beam displacer 801 between the cylindrical lens unit 211 and the dichroic mirror 209 in the optical path of the second laser L2. The beam displacer 801 has the same structure as the above-described beam displacer 231 (refer to Figure 12 ). In this laser processing apparatus 600, the second laser L2 can be irradiated to the processing target object 1 in a parallel beam. The control section 216 of the present embodiment controls the irradiation timing of the second laser L2 so as to control the solidification speed of the molten solidification region 11 in such a manner that a crack is not generated in the thickness direction.

[0295] In the laser processing apparatus 800, the first laser LI has a wavelength close to or longer than the band gap, and a sharply rising pulse waveform. The pulse waveform of the first laser LI is a rectangular waveform or a Gaussian waveform. The first laser LI is irradiated for only a short time at the depth position of the slice predetermined surface in the processing target object 1 or a deeper depth position than that. By this irradiation of the first laser LI, the first-stage absorption phenomenon is induced with a minimum height (width in the thickness direction) at the slice predetermined surface.

[0296] On the other hand, the second laser L2 has a wavelength that is not absorbed by the machining target object 1 in the ground state. The second laser L2 has a pulse waveform. The pulse waveform of the second laser L2 is a rectangular waveform or a Gaussian waveform. The second laser L2 is irradiated to the machining target object 1 for a short time and intermittently. Thereby, the second stage is intermittently generated, and the modified points S are inhibited from separating from the thickness direction of the slice predetermined surface. At the same time, in order to easily perform the division from the slice predetermined surface, the modified region 7 along the slice predetermined surface is formed by a method of simultaneously irradiating a plurality of points or the like. The propagation of the crack in the thickness direction is inhibited.

[0297] For the laser machining device 800 herein, the first laser L1 and the second laser L2 irradiated to the machining target object 1 have the following characteristics.

[0298] (Wavelength)

[0299] First laser L1: 1026 to 1064 nm

[0300] Second laser L2: 1180 to 1700 nm

[0301] (Beam quality (M 2 value)

[0302] First laser L1: 1.0

[0303] Second laser L2: less than 3.0

[0304] (Pulse duration)

[0305] First laser L1: 10 to 50 ns

[0306] Second laser L2: 0.3 to 0.7 μs

[0307] (Pulse rise time)

[0308] First laser L1: less than 3 ns

[0309] Second laser L2: less than 50 ns

[0310] (Pulse waveform)

[0311] First laser L1: rectangular waveform or Gaussian waveform

[0312] Second laser L2: rectangular waveform or Gaussian waveform

[0313] (Peak intensity)

[0314] First laser L1: 70 W

[0315] Second laser L2: 150 to 250 W

[0316] (repetition frequency)

[0317] first laser L1: 300 kHz or less

[0318] second laser L2: 300 kHz or less

[0319] (irradiation timing)

[0320] first laser L1: arbitrary

[0321] second laser L2: 20 to 30 ns later

[0322] (multiple pulse trains)

[0323] (condensing system)

[0324] first laser L1: condensing priority

[0325] second laser L2: path priority

[0326] (aberration correction)

[0327] first laser L1: yes

[0328] second laser L2: no

[0329] (symmetry of beam profile)

[0330] first laser L1: rotational symmetry (circular)

[0331] second laser L2: quadrilateral

[0332] (NA)

[0333] first laser L1: 0.7 or more

[0334] second laser L2: 0.6 or more

[0335] In the laser processing apparatus 800, the above-described effects produced by the laser processing apparatus 200 can also be achieved. In particular, in the laser processing apparatus 800, the modified region 7 is a cutting start region when the workpiece 1 is sliced. Thus, the workpiece 1 can be sliced with the modified region 7 as the start of cutting.

[0336] Figure 22 is a schematic diagram showing the structure of a laser processing apparatus 820 according to a modification of the seventh embodiment. The laser processing apparatus 820 according to the modification is similar to the laser processing apparatus 800 (refer to FIG. 8) described above, and thus the same components are denoted by the same reference numerals, and a description thereof will not be repeated. Figure 21The difference is that the former irradiates the second laser light L2 from the side of the processing target object 1. In comparison with the laser processing apparatus 800 described above, the laser processing apparatus 820 does not have the dichroic mirror 209, but further has a condensing optical system 821. In the laser processing apparatus 820, the condensing optical system 210 condenses only the first laser light L1 to the processing target object 1.

[0337] The condensing optical system 821 condenses the second laser light L2 that has passed through the cylindrical lens unit 211 and is reflected by the mirrors 822, 823 to the processing target object 1. The condensing optical system 821 is disposed opposite to the side of the processing target object 1. The condensing optical system 821 irradiates the second laser light L2 to the side of the processing target object 1 as a laser light incident surface. The condensing optical system 821 has the same structure as the condensing optical system 210. As the condensing optical system 821, it is not necessary to use an optical system having higher performance than the condensing optical system 210.

[0338] In the laser processing apparatus 820, the first laser light L1 has a wavelength close to or longer than the band gap, and a steeply rising pulse waveform. The first laser light L1 is irradiated to the slice predetermined surface in the processing target object 1. The first laser light L1 satisfies the damage suppression condition. By this irradiation of the first laser light L1, the induction of the first-stage temporary absorption region is minimized. On the other hand, the second laser light L2 has a wavelength that is not absorbed by the processing target object 1 in the ground state, a large energy, and a long pulse duration. The second laser light L2 satisfies the separation force priority condition. The beam profile of the second laser light L2 is along the slice predetermined surface. The second laser light L2 is irradiated to the slice predetermined surface from a direction along the slice predetermined surface with the beam profile along the slice predetermined surface. Thus, the second stage is continued for a long time, the molten solidification region 11 is enlarged in the slice predetermined surface, and a large separation force can be generated.

[0339] For the laser processing apparatus 820 here, it is configured such that the first laser light L1 and the second laser light L2 irradiated to the processing target object 1 have the following characteristics.

[0340] (wavelength)

[0341] First laser light L1: 1026 to 1064 nm

[0342] Second laser light L2: 1180 to 7500 nm

[0343] (brightness (M 2 value)

[0344] First laser light L1: 1.0

[0345] Second laser light L2: less than 2.0

[0346] (pulse duration)

[0347] First laser L1: 10-30 ns

[0348] Second laser L2: 0.7-5 μs

[0349] (Pulse rise time)

[0350] First laser L1: less than 3 ns

[0351] Second laser L2: less than 50 ns

[0352] (Pulse waveform)

[0353] First laser L1: rectangular waveform or Gaussian waveform Second laser L2: rear rise waveform (quadratic curve) (peak intensity)

[0354] First laser L1: 70 W

[0355] Second laser L2: 150-250 W (repetition frequency)

[0356] First laser L1: 150 kHz or less

[0357] Second laser L2: 150 kHz or less (irradiation time point)

[0358] First laser L1: arbitrary

[0359] Second laser L2: 20-30 ns later (condensing system)

[0360] First laser L1: condensing priority

[0361] Second laser L2: path priority (aberration correction)

[0362] First laser L1: yes

[0363] Second laser L2: according to depth (symmetry of beam profile)

[0364] First laser L1: rotational symmetry (circular)

[0365] Second laser L2: long strip along the slice predetermined surface (NA)

[0366] First laser L1: 0.7 or more

[0367] Second laser L2: 0.05-0.4

[0368] In the laser processing apparatus 820, the above-described effects of the laser processing apparatus 800 can be achieved. In the laser processing apparatus 820, by irradiating the second laser L2 in the direction along the slice predetermined surface, the direction of the modification point S and the crack propagation can be controlled (can be selectively induced) in the direction along the slice predetermined surface.

[0369] [The eighth embodiment]

[0370] Next, the laser processing apparatus of the eighth embodiment will be described. Hereinafter, points different from the first embodiment will be described, and the repeated description will be omitted.

[0371] Figure 23 The laser processing apparatus 900 of the eighth embodiment illustrated is a processing apparatus used when manufacturing, for example, an interposer or a micro flow path, and can form a modification region 7 extending in two dimensions or three dimensions in a processing target object 1. The modification region 7 of the present embodiment is a removal predetermined region selectively developed and removed by etching or the like. The laser processing apparatus 900 induces the modification region 7 at a super high speed by irradiating the second laser L2 toward the processing target object 1 from a plurality of directions.

[0372] The laser processing apparatus 900 and the above-described laser processing apparatus 200 (refer to Figure 9 ) differ in the device structure in that the former further includes a half mirror 901, 902, a condensing optical system 903, 904, and a baffle 907 to 909. The half mirror 901 is disposed between the cylindrical lens unit 211 and the dichroic mirror 209 on the optical path of the second laser L2. The half mirror 901 reflects a part of the second laser L2 that has passed through the cylindrical lens unit 211, and transmits the other part of the second laser L2.

[0373] The half mirror 902 is disposed on the downstream side of the half mirror 901 on the optical path of the second laser L2. The half mirror 902 reflects a part of the second laser L2 reflected by the half mirror 901, and transmits the other part of the second laser L2.

[0374] The condensing optical system 903 condenses the second laser light L2 reflected by the half mirror 902 toward the machining object 1. The condensing optical system 903 is disposed opposite to the side surface of the machining object 1. The condensing optical system 903 makes the second laser light L2 incident on the side surface of the machining object 1 as a laser light incident surface. The condensing optical system 903 has the same structure as the condensing optical system 210. The condensing optical system 904 condenses the second laser light L2 that has passed through the half mirror 902 and is reflected by the mirrors 905 and 906 toward the machining object 1. The condensing optical system 904 is disposed opposite to the condensing optical system 210 with the machining object 1 interposed therebetween. The condensing optical system 904 makes the back surface (or the surface) opposite to the laser light incident surface, that is, the surface (or the back surface) of the condensing optical system 210 as a laser light incident surface, and makes the second laser light L2 incident thereon. The condensing optical system 904 has the same structure as the condensing optical system 210. As the condensing optical systems 903 and 904, optical systems having higher performance than the condensing optical system 210 need not be used.

[0375] The shutters 907 to 909 control the interruption and opening of the second laser light L2. The shutter 907 is disposed, for example, between the half mirror 901 and the dichroic mirror 209 on the optical path of the second laser light L2. The shutter 908 is disposed, for example, between the half mirror 902 and the condensing optical system 903 on the optical path of the second laser light L2. The shutter 909 is disposed, for example, between the half mirror 902 and the mirror 905 on the optical path of the second laser light L2.

[0376] The control section 216 of the present embodiment achieves irradiation of the second laser light L2 in multiple directions toward the machining object 1 by appropriately switching the opening and closing of the shutters 907 to 909. For example, the control section 216 can irradiate the second laser light L2 toward the machining object 1 from any one of the surface side, the back surface side, and the side surface side of the machining object 1 by timely opening only any one of the shutters 907 to 909. Alternatively, the switching of the irradiation direction of the second laser light L2 can be achieved by combining a plurality of light sources and emitting light at appropriate time points.

[0377] In the laser processing apparatus 900, the first laser light L1 has a wavelength close to or longer than the band gap, and a steeply rising pulse waveform. The first laser light L1 is irradiated toward a removal scheduled position of the machining object 1. The irradiation of such first laser light L1 minimizes the induction of the first-stage temporary absorption region. On the other hand, the second laser light L2 has a wavelength that is not absorbed by the machining object 1 in the ground state, a large energy, and a long pulse duration. The second laser light L2 is irradiated along a removal scheduled path of the machining object 1. The irradiation of such second laser light L2 causes the second-stage long duration to continue for an arbitrary length, and forms the modified region 7 that is favorable for etching.

[0378] The removal predetermined path is an imaginary path used to form a removal predetermined area on the workpiece 1. The removal predetermined path is not limited to a straight line; it can also be curved, a three-dimensional shape composed of these, or a shape whose coordinates are specified. The removal predetermined path is a modification region forming predetermined path. The modification region forming predetermined path is a path predetermined to form the modification region 7.

[0379] The laser processing apparatus 900 described herein is configured such that the first laser L1 and the second laser L2 irradiating the workpiece 1 have the following characteristics. Furthermore, "aperture" corresponds to the diameter on a cross-section perpendicular to the extending direction of the modified region 7, which serves as a predetermined removal area.

[0380] (wavelength)

[0381] First laser L1: 1026~1064nm

[0382] Second laser L2: 1180~7500nm

[0383] (beam mass (M) 2 value))

[0384] First laser L1: 1.0

[0385] Second laser L2: less than 3.0

[0386] (Pulse duration)

[0387] First laser L1: 10–30 ns

[0388] Second laser L2: 0.1–5 μs

[0389] (Pulse rise time)

[0390] First laser L1: less than 3ns

[0391] Second laser L2: less than 50ns

[0392] (Pulse waveform)

[0393] First laser L1: rectangular waveform or Gaussian waveform; Second laser L2: rising waveform (square curve) (peak intensity).

[0394] First laser L1: 70W

[0395] Second laser L2: 80-180W (repetition frequency)

[0396] First laser L1: below 80kHz

[0397] Second laser L2: below 80kHz (irradiation time point)

[0398] First laser L1: arbitrary

[0399] Second laser L2: 20-30ns later (focusing system)

[0400] First laser L1: Focusing priority

[0401] Second laser L2: Path-first (aberration correction)

[0402] First laser L1: Yes

[0403] Second laser L2: Depends on depth and aperture (symmetry of beam profile)

[0404] First laser L1: rotationally symmetric (perfect circle)

[0405] Second laser L2: Dependent on modified region 7 (NA)

[0406] First laser L1: 0.7 or higher

[0407] Second laser L2: 0.05~0.4

[0408] In the laser processing apparatus 900, the effects described above, produced by the laser processing apparatus 200, can also be achieved. Specifically, in the laser processing apparatus 900, the modified region 7 is a predetermined removal region extending in a two-dimensional or three-dimensional shape within the workpiece 1. In this case, the modified region 7 is selectively removed by etching or the like, thereby forming a space extending in a two-dimensional or three-dimensional shape within the workpiece.

[0409] In the laser processing apparatus 900, a second laser L2 is irradiated onto the workpiece 1 from a desired irradiation direction, thereby enabling ultra-high-speed and three-dimensional induction of the progress of the modified region 7. A modified region 7 with a desired three-dimensional shape can be formed in the workpiece 1.

[0410] Furthermore, in the laser processing apparatus 900, sometimes due to limitations in the apparatus structure, it is difficult to ensure that the irradiation direction of the second laser L2 aligns with the direction of extension of the predetermined removal path. In such cases, by shortening the pulse duration of the second laser L2 and intermittently irradiating and scanning it, the modified region 7 can be advanced in a direction other than the irradiation direction of the second laser L2. The optical system of the laser processing apparatus 900 is not limited to... Figure 23 The structure shown can be any other structure as long as it can irradiate the workpiece 1 from multiple directions. For example, by using a high-speed bifurcation unit (EOM or AOM, etc.), the optical path can be switched instantaneously, which can significantly improve the utilization efficiency of the output of the second laser L2.

[0411] Figure 24 is a schematic diagram showing the structure of a laser processing apparatus 920 which is a modification of the eighth embodiment. The laser processing apparatus 920 of the modification differs from the above-described laser processing apparatus 900 (refer to Figure 23 ) in the structure of the apparatus in that the former does not have the dichroic mirror 209, the half mirrors 901, 902, the condensing optical system 904, the mirrors 905, 906, and the baffles 907 to 909. In the laser processing apparatus 920, the condensing optical system 210 condenses only the first laser light Ll toward the processing object 1. In the laser processing apparatus 920, the condensing optical system 903 condenses the second laser light L2 which has passed through the cylindrical lens unit 211 and has been reflected by the mirrors 921, 922, toward the processing object 1.

[0412] In the laser processing apparatus 920, the first laser light Ll has a large wavelength which can be absorbed by the processing object 1, and a steeply rising pulse waveform. By irradiating such first laser light Ll, only the first stage is implemented with a minimum molten solidification region 11. On the other hand, the second laser light L2 has a wavelength which is completely transparent to the processing object 1, a large energy, and a long pulse duration. By irradiating such second laser light L2, the second stage is continued for a long time, a modified region 7 which is favorable for etching is formed, and the modified region 7 is enlarged to an arbitrary size.

[0413] In the above, in the laser processing apparatus 920, the above-described effects produced by the above-described laser processing apparatus 900 can also be achieved. In addition, in the processing performed by the laser processing apparatus 920, the laser light L is scanned in a three-dimensional shape with a narrow pitch, unlike the case where the modified region 7 which is a cutting starting point region is formed inside the processing object 1. Therefore, the modified region 7 can be connected by slowing down the scanning speed and reducing the processing pitch. According to the processing performed by the laser processing apparatus 920, the modified region 7 can be developed to a state which is favorable for etching in the second stage.

[0414] [Ninth Embodiment]

[0415] Next, a laser processing apparatus of the ninth embodiment will be described.

[0416] According to the laser processing apparatus 1000 of the ninth embodiment shown in Figure 25 , irradiation of the first laser light Ll and the second laser light L2 toward the processing object 1 is implemented by one light source 1001. The laser processing apparatus 1000 has the light source 1001, an external modulator 1002, a branching optical element 1003, a combining optical element 1004, a mirror 1005, a mirror 1006, a condensing optical system 1007, and a control section 1008.

[0417] Light source 1001 emits a pulsed laser L (pulse oscillation). External modulator 1002 modulates the laser L emitted from light source 1001, thereby splitting it into a first laser L1 and a second laser L2 by a suitable downstream modulator, i.e., a bifurcation optical element 1003. There are no particular limitations on the external modulator 1002, and various modulators can be used.

[0418] A laser L modulated by an external modulator 1002 is incident into a bifurcation optical element 1003. The short-wavelength side, either horizontally or vertically polarized, is transmitted as a first laser L1, and the long-wavelength side, either vertically or horizontally polarized, is reflected as a second laser L2. The bifurcation optical element 1003 is, for example, a dichroic mirror or a polarizer. A connecting optical element 1004 allows the first laser L1 transmitted through the bifurcation optical element 1003 to pass through, and reflects the second laser L2, which was reflected by mirrors 1005 and 1006, to pass through the bifurcation optical element 1003. The structure of the connecting optical element 1004 is the same as that of the bifurcation optical element 1003.

[0419] The focusing optical system 1007 focuses the first laser L1, which has passed through the bonding optical element 1004, and the second laser L2, which is reflected by the bonding optical element 1004, onto the object to be processed 1. The focusing optical system 1007 and the aforementioned focusing optical system 210 (see reference 1007) are related. Figure 9 The structure is the same as that of the control unit 216 (see above). The control unit 1008 controls the operation of the light source 1001 and the external modulator 1002. The control unit 1008 has the same structure as the control unit 216 (see above). Figure 9 The same function. The light source 1001, the external modulator 1002 and the control unit 1008 constitute the first irradiation unit and the second irradiation unit.

[0420] In the laser processing apparatus 1000 configured as described above, a laser L is emitted from a light source 1001 and modulated by an external modulator 1002. A portion of the laser L modulated by the external modulator 1002 is transmitted as a first laser L1 through a bifurcation optical element 1003. The other portion of the laser L modulated by the external modulator 1002 is reflected by the bifurcation optical element 1003 as a second laser L2.

[0421] The first laser L1, which passes through the bifurcation optical element 1003, continues to pass through the bonding optical element 1004 and is then irradiated onto the workpiece 1 by the focusing optical system 1007. As a result, the absorptivity of a portion of the workpiece 1 temporarily increases. During this period of increased absorptivity H, the second laser L2, reflected by the bifurcation optical element 1003, is successively reflected by mirrors 1005, 1006, and the bonding optical element 1004, and is then irradiated onto a portion of the workpiece 1 by the focusing optical system 1007.

[0422] In the laser processing apparatus 1000, the above-described advantageous effects produced by the laser processing apparatus 200 can also be achieved. In the laser processing apparatus 1000, one light source 1001 can also be used.

[0423] [Modified Example]

[0424] The present application is not limited to the above-described embodiments.

[0425] In the above-described embodiments, the second light source 202 is not particularly limited, and a cheap and high-output gas laser and a multi-mode laser light source can also be used. As the second light source 202, for example, a laser light source having a wavelength in the region of 1.8 to 2.3 μm that has been popularized in the field of dentistry or the field of plastic surgery can be used. Also, for at least either one of the first light source 201 and the second light source 202, it is not necessarily a laser light source, but can be a bulb or the like that outputs incoherent light, can be a plasma light source, or can be a microwave oscillator that generates microwaves.

[0426] In the above-described embodiments, the number of the second light sources 202 is not particularly limited, and two or more second light sources 202 can be provided. In this case, during the absorption rate rise period H in which the absorption rate of a part of the region temporarily rises, a plurality of second lasers L2 are sequentially and simultaneously irradiated from the plurality of second light sources 202 at least a part of which.

[0427] In the above-described embodiments, the first laser Ll and the second laser L2 are incident from a perpendicular direction that is perpendicular to the surface, the back surface, or the side surface of the processing target object 1, but are not limited thereto. At least either one of the first laser Ll and the second laser L2 can be incident from an inclined direction that is inclined with respect to the perpendicular direction.

[0428] The processing apparatus of one aspect of the present application can also be applied to other processing other than the above-described processing, and it is important to form a modified region 7 in the processing target object 1. The modified region 7 can be, for example, a crystalline region, a recrystallized region, or a gettered region formed in the inside of the processing target object 1. The crystalline region is a region that maintains the structure of the processing target object 1 before processing. The recrystallized region is a region that solidifies in the form of a single crystal or a polycrystal when re-solidified after being temporarily evaporated, ionized, or melted. The gettered region is a region that exhibits a gettering effect of collecting and capturing impurities such as heavy metals, and can be continuously formed or intermittently formed. Also, for example, the processing apparatus can be applied to processing such as ablation.

[0429] An aspect of the present application can also be understood as a laser processing apparatus, a modified region forming apparatus, or a chip manufacturing apparatus. Also, an aspect of the present application can also be understood as a processing method, a laser processing method, a modified region forming method, or a chip manufacturing method. In the above-described embodiments and the above-described modified examples, at least a part of the structures of the respective embodiments and the respective modified examples can be appropriately combined.

[0430] [Explanation of symbols]

[0431] 1: object to be processed;

[0432] 7: modified region;

[0433] 100, 200, 220, 230, 240, 300, 320, 400, 420, 500, 600, 700, 800, 820, 900, 1000: laser processing apparatus (processing apparatus);

[0434] 201: first light source (first irradiation section);

[0435] 202: second light source (second irradiation section);

[0436] 216: control section (first irradiation section, second irradiation section);

[0437] 1001: light source (first irradiation section, second irradiation section);

[0438] 1002: external modulator (first irradiation section, second irradiation section);

[0439] 1008: control section (first irradiation section, second irradiation section);

[0440] L1: first laser light (first light);

[0441] L2: second laser light (second light);

[0442] S: modified point.

Claims

1. A processing apparatus, wherein it is a processing apparatus that forms a modification point constituting a modification region in a processing target, i.e., silicon, the processing apparatus comprises: a first irradiation section that irradiates a first light to the processing target to temporarily increase an absorption rate in a part of a region of the processing target before the irradiation of the first light; and a second irradiation section that irradiates a second light to the part of the region during an absorption rate increase period in which the absorption rate in the part of the region is temporarily increased, the second light has a longer wavelength than the first light, the wavelength of the second light is 1000 to 8500 nm, The M 2 value of the second light is greater than the M 2 value of the first light.

2. The processing apparatus according to claim 1, wherein the second light has a higher energy than the first light.

3. The processing apparatus according to claim 1, wherein the second light has a lower peak intensity than the first light.

4. The processing apparatus according to any one of claims 1 to 3, wherein the second light is a light that does not form a modification point when the second light is irradiated alone to the processing target.

5. The processing apparatus according to any one of claims 1 to 3, wherein the irradiation direction of the second light to the processing target is different from the irradiation direction of the first light to the processing target.

6. The processing apparatus according to any one of claims 1 to 3, wherein the numerical aperture of the second light is different from the numerical aperture of the first light.

7. The processing apparatus according to any one of claims 1 to 3, wherein the beam profile of the second light is different from the beam profile of the first light.

8. The processing apparatus according to any one of claims 1 to 3, wherein the pulse width of the second light is different from the pulse width of the first light.

9. The processing apparatus according to any one of claims 1 to 3, wherein the pulse waveform of the second light is different from the pulse waveform of the first light.

10. The processing apparatus according to any one of claims 1 to 3, wherein the polarization direction of the second light is different from the polarization direction of the first light.

11. The processing apparatus according to any one of claims 1 to 3, wherein the modification region is a cutting start point region in which the processing target is cut along a thickness direction.

12. The processing apparatus according to any one of claims 1 to 3, wherein the modification region is a cutting start point region in which the processing target is cut along a direction intersecting the thickness direction.

13. The processing apparatus according to any one of claims 1 to 3, wherein the modification region is a predetermined region to be removed that extends in two dimensions or three dimensions in the processing target.

14. The processing apparatus according to any one of claims 1 to 3, wherein the modification region is a crystalline region, a recrystallized region, or a gettering region formed in the inside of the processing target.

15. The processing apparatus according to any one of claims 1 to 3, wherein the first irradiation section is constituted by a first light source that emits the first light, The second irradiation section is composed of a second light source that emits the second light and a control section that controls a timing of irradiation of the second light source in such a manner that the second light is irradiated toward the partial region during the period of the rise in the absorption rate.

16. The processing apparatus according to any one of claims 1 to 3, wherein the first irradiation section and the second irradiation section are composed of a light source and an external modulator that modulates light emitted from the light source, a part of the light emitted from the light source and modulated by the external modulator is irradiated toward the processing target as the first light, another part of the light emitted from the light source and modulated by the external modulator is irradiated toward the partial region as the second light during the period of the rise in the absorption rate.

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