Laser processing apparatus, microscope apparatus, and laser processing method

Abstract

The present invention provides a laser processing apparatus, a microscope apparatus, and a laser processing method that can suppress the deterioration of the quality of the processed cross-section. [Solution] The laser processing apparatus 20 includes a polarization adjustment unit 45 that adjusts the polarization direction of the laser light L3 so that the laser light L4 includes a first component C1 in a first polarization direction P1 and a second component C2 in a second polarization direction P2; a spatial light modulator 46 that modulates the first component C1 of the laser light L4 emitted from the polarization adjustment unit 45 and emits it as modulated light Lm, and emits the second component C2 of the laser light L4 as unmodulated light Ln; a ​​lens 49 that focuses the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 toward the sample A to form a single continuous irradiation region R on the sample A that includes the modulated light Lm and the unmodulated light Ln; and a galvanometer mirror 48 for scanning the irradiation region R with respect to the sample A.

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus, a microscope apparatus, and a laser processing method.

Background Art

[0002] Patent Document 1 describes a laser processing method. In this method, a groove processing step of irradiating a workpiece with a laser beam for groove processing to form a groove having a predetermined depth is performed. The groove processing step consists of a pre-processing step and a main processing step. In the pre-processing step, a preliminary groove is formed by irradiating the groove processing region of the workpiece with a first laser beam for groove processing. In the main processing step, the groove bottom surface constituting the preliminary groove is irradiated with a second laser beam for groove processing so that the groove depth of the preliminary groove becomes a predetermined depth, and the groove bottom surface is processed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the laser processing method described in Patent Document 1 above, the bottom surface of the groove is the processing surface irradiated with the laser beam, and the inner surface of the groove along the scanning direction of the laser beam becomes the processing cross-section. In the above technical field, there may be a case where improvement in the quality of this processing cross-section is required. That is, when the pulse width of the laser beam becomes large, the properties of the processing cross-section change due to the influence of heat generated during processing, and as a result, the quality of the processing cross-section may deteriorate.

[0005] In contrast, by using an ultrashort pulse laser with a pulse width of 1 ps or less during the processing, changes in the properties of the processed surface due to heat can be suppressed. However, when processing is performed using an ultrashort pulse laser, a new fine periodic structure (for example, a laser-induced periodic surface structure (LIPSS)) may be formed on the processed surface, which may lead to a problem of reduced quality of the processed surface.

[0006] Therefore, the present invention aims to provide a laser processing apparatus, a microscope apparatus, and a laser processing method that can suppress the deterioration of the quality of the processed cross-section. [Means for solving the problem]

[0007] The laser processing apparatus according to the present invention is [1] a laser processing apparatus for forming a processed cross section on an object by irradiating the object with laser light, comprising: a laser output unit for outputting laser light having a pulse width of 1 ps or less; a polarization adjustment unit that receives the incident laser light output from the laser output unit, adjusts the polarization direction of the laser light so that the laser light includes a first component in a first polarization direction and a second component in a second polarization direction perpendicular to the first polarization direction, and emits the adjusted laser light; a spatial light modulator that receives the incident laser light emitted from the polarization adjustment unit, modulates the first component of the laser light and emits it as modulated light, and emits the second component of the laser light as unmodulated light; and the modulated light and the unmodulated light emitted from the spatial light modulator A laser processing apparatus comprising: a focusing unit that focuses light toward an object to form a single continuous irradiation area on the object including the modulated light and the unmodulated light; a scanning unit for scanning the irradiation area toward the object, wherein the polarization adjustment unit adjusts the polarization direction of the laser light so that the intensity of the first component in the laser light is equal to or greater than the intensity of the second component; the focusing unit focuses the modulated light and the unmodulated light in the irradiation area such that the first polarization direction is along a first direction intersecting the optical axis direction of the modulated light, and the second polarization direction is along a second direction intersecting the optical axis direction and the first direction; and the scanning unit scans the irradiation area toward the object along the second direction to form the processed cross section toward the object along the second direction.

[0008] The laser processing method according to the present invention is described as follows: [9] "A laser processing method for forming a processed cross section on an object by irradiating the object with laser light, comprising: a polarization adjustment step of adjusting the polarization direction of the laser light having a pulse width of 1 ps or less to include a first component in a first polarization direction and a second component in a second polarization direction perpendicular to the first polarization direction, and generating the adjusted laser light; a modulation step of injecting the laser light generated in the polarization adjustment step into a spatial light modulator, modulating the first component of the laser light with the spatial light modulator and emitting it from the spatial light modulator as modulated light, and emitting the second component of the laser light from the spatial light modulator as unmodulated light; and focusing the modulated light and the unmodulated light emitted from the spatial light modulator toward the object." The laser processing method comprises: a focusing step of forming a single continuous irradiation area on the object including the modulated light and the unmodulated light by illuminating it; and a scanning step of scanning the irradiation area with respect to the object, wherein in the polarization adjustment step, the polarization direction of the laser light is adjusted so that the intensity of the first component in the laser light is equal to or greater than the intensity of the second component; in the focusing step, the modulated light and the unmodulated light are focused in the irradiation area such that the first polarization direction is along a first direction intersecting the optical axis direction of the modulated light, and the second polarization direction is along a second direction intersecting the optical axis direction and the first direction; and in the scanning step, the irradiation area is scanned with respect to the object along the second direction to form the processed cross section on the object along the second direction.

[0009] In this laser processing apparatus and laser processing method, a processed cross-section is formed on an object by irradiating it with laser light. The laser light is an ultrashort pulse laser with a pulse width of 1 ps or less. Therefore, it is possible to suppress the deterioration of the quality of the processed cross-section caused by changes in the properties of the processed cross-section due to the effects of heat. Furthermore, in this laser processing apparatus and laser processing method, it is also possible to suppress the deterioration of the quality of the processed cross-section caused by the formation of a fine periodic structure on the processed cross-section by using an ultrashort pulse laser, as described below.

[0010] In other words, in this laser processing apparatus and laser processing method, the polarization direction of the laser light is adjusted so that the laser light includes a first component in a first polarization direction and a second component in a second polarization direction perpendicular to the first polarization direction. At this time, the polarization direction of the laser light is adjusted so that the intensity of the first component in the laser light is equal to or greater than the intensity of the second component. Furthermore, the spatial light modulator modulates the first component of the laser light after the polarization direction adjustment and emits it as modulated light, while emitting the second component of the laser light after the polarization direction adjustment as unmodulated light (without modulation).

[0011] Furthermore, by focusing the modulated and unmodulated light emitted from the spatial light modulator toward the object, a single continuous illumination region including the modulated and unmodulated light is formed on the object. At this time, the modulated and unmodulated light are focused in the illumination region such that the first polarization direction is along a first direction intersecting the optical axis direction of the modulated light, and the second polarization direction is along a second direction intersecting the optical axis direction and the first direction. Then, by scanning the illumination region toward the object along the second direction, a processed cross-section along the second direction is formed on the object.

[0012] According to the inventors' findings, when scanning a single continuous irradiation region formed by focusing modulated and unmodulated light onto an object, if the modulated light (first component) has an intensity greater than or equal to that of the unmodulated light (second component), and if the first polarization direction, which is the polarization direction of the modulated light, intersects the scanning direction (second direction), while the second polarization direction, which is the polarization direction of the unmodulated light, is aligned with the scanning direction, then the formation of a fine periodic structure is suppressed in the processed cross-section formed along the scanning direction. Therefore, this laser processing apparatus and laser processing method can suppress a deterioration in the quality of the processed cross-section.

[0013] Furthermore, a single continuous illumination region including modulated and unmodulated light means a state in which at least a portion of the illumination region of the modulated light on the object overlaps with at least a portion of the illumination region of the unmodulated light on the object. In addition, the illumination region of the modulated light on the object is the range in the object where the intensity of the modulated light is 20% or more of the peak, and the illumination region of the object where the intensity of the unmodulated light on the object is 20% or more of the peak.

[0014] The laser processing apparatus according to the present invention may also be [2] "the laser processing apparatus according to [1] above, wherein the spatial light modulator includes a liquid crystal layer and modulates the first component according to a modulation pattern displayed on the liquid crystal layer." In this case, by adjusting the modulation pattern displayed on the liquid crystal layer of the spatial light modulator, it becomes possible to easily perform various modulations, such as self-correcting the shape distortion of the spatial light modulator or adjusting the modulated light to unmodulated light that has been spatially shifted due to the shape distortion.

[0015] The laser processing apparatus according to the present invention may also be [3] "the laser processing apparatus according to [1] or [2] above, wherein the polarization adjustment unit adjusts the polarization direction of the laser light so that the ratio of the intensity of the first component to the intensity of the second component in the laser light is 50:50 or more and 90:10 or less." In this case, the formation of a microperiodic structure in the processed cross-section can be further suppressed.

[0016] The laser processing apparatus according to the present invention may also be [4] "the laser processing apparatus according to any one of [1] to [3] above, wherein the focusing unit focuses the modulated light and the unmodulated light such that the distance between the peak position of the intensity of the modulated light and the peak position of the intensity of the unmodulated light in the irradiation area is 80% or less of the diameter of the first irradiation area formed by the focusing of the modulated light." In this case, the formation of a microperiodic structure in the processed cross section can be further suppressed.

[0017] The laser processing apparatus according to the present invention may also be [5] "the laser processing apparatus according to [4] above, wherein the focusing unit focuses the modulated light and the unmodulated light such that, in the irradiation area, the peak position of the intensity of the modulated light and the peak position of the intensity of the unmodulated light overlap each other at least partially." In this case, the formation of a microperiodic structure in the processed cross section can be suppressed more reliably.

[0018] Furthermore, the statement that the peak positions of the modulated light intensity and the peak positions of the unmodulated light intensity overlap at least partially means that at least a portion of the region where the modulated light intensity is 95% or more of the peak overlaps with at least a portion of the region where the unmodulated light intensity is 95% or more of the peak.

[0019] The laser processing apparatus according to the present invention may also be [6] "the laser processing apparatus according to [4] above, wherein the focusing unit focuses the modulated light and the unmodulated light such that, in the irradiation area, the peak of the intensity of the unmodulated light is shifted toward the processing cross-section side relative to the peak of the intensity of the modulated light." Thus, if the peak of the intensity of the modulated light and the peak of the intensity of the unmodulated light do not coincide with each other in the irradiation area, the peak of the intensity of the unmodulated light may be shifted toward the processing cross-section side relative to the peak of the intensity of the modulated light.

[0020] The laser processing apparatus according to the present invention may also be [7] "the laser processing apparatus according to any of [1] to [6] above, wherein the polarization adjustment unit includes a half-wave plate." In this case, the polarization direction of the laser light can be easily controlled by adjusting the half-wave plate.

[0021] The microscope apparatus according to the present invention may also be a microscope apparatus comprising [8] "a laser processing apparatus as described in any of [1] to [7] above, and a microscope unit for observing the processed cross-section." In this case, since the deterioration of the quality of the processed cross-section is suppressed, it becomes possible to obtain highly accurate observation results of the processed cross-section. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a laser processing apparatus, a microscope apparatus, and a laser processing method capable of suppressing a decrease in the quality of a processed cross section.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a schematic diagram showing a part of the microscope apparatus according to the present embodiment. [Figure 2] FIG. 2 is a schematic diagram showing another part of the microscope apparatus according to the present embodiment. [Figure 3] FIG. 3 is a diagram showing the polarization direction of the laser beam at each stage of the laser optical system shown in FIG. 2. [Figure 4] FIG. 4 is a diagram showing an example of the modulation pattern displayed on the spatial light modulator. [Figure 5] FIG. 5 is a schematic diagram showing a state of processing a sample with a laser beam according to a conventional example and a SEM image showing a processed cross section of the sample according to the conventional example. [Figure 6] FIG. 6 is a diagram showing an example of an irradiation region formed on the sample. [Figure 7] FIG. 7 is a schematic perspective view showing a state of scanning the irradiation region. [Figure 8] FIG. 8 is a SEM image showing a processed cross section. [Figure 9] FIG. 9 is a diagram showing a state of a processed cross section when the ratio of the intensity of the modulated light to the intensity of the unmodulated light is changed. [Figure 10] FIG. 10 is a SEM image showing a processed cross section when the first polarization direction intersects the processed cross section in the irradiation region and the intensity of the first component is greater than or equal to the intensity of the second component. [Figure 11] FIG. 11 is a SEM image showing a processed cross section when the first polarization direction intersects the processed cross section in the irradiation region and the intensity of the first component is less than the intensity of the second component. [Figure 12] FIG. 12 is a SEM image showing a processed cross section when the first polarization direction is along the processed cross section in the irradiation region and the intensity of the first component is greater than or equal to the intensity of the second component. [Figure 13]Figure 13 is an SEM image showing the processed cross-section when the first polarization direction in the irradiation region is aligned with the processed cross-section and the intensity of the first component is less than the intensity of the second component. [Figure 14] Figure 14 shows the intensity distribution of modulated and unmodulated light and the processed cross-section related to the modified example. [Figure 15] Figure 15 shows the intensity distribution of modulated and unmodulated light and the processed cross-section for the comparative example. [Figure 16] Figure 16 is a schematic diagram showing a modified spatial light modulator. [Modes for carrying out the invention]

[0024] Hereinafter, a laser processing apparatus, a microscope apparatus, and a laser processing method according to one embodiment will be described with reference to the drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numeral, and redundant explanations may be omitted. In addition, each figure may show a Cartesian coordinate system including a first axis defining the first direction D1, a second axis defining the second direction D2 intersecting the first direction D1, and a third axis defining the third direction D3 intersecting the first direction D1 and the second direction D2.

[0025] Figure 1 is a schematic diagram showing a part of the microscope apparatus according to this embodiment. Figure 2 is a schematic diagram showing another part of the microscope apparatus according to this embodiment. The microscope apparatus 1 shown in Figures 1 and 2 includes, as will be described later, a focused ion beam (FIB) apparatus that irradiates a sample with focused ions (e.g., Ga ions) to perform etching on the sample, a scanning electron microscope (SEM) apparatus that irradiates a sample with an electron beam to observe the sample, and a laser processing apparatus that irradiates a sample with laser light to perform laser processing (e.g., ablation processing) on ​​the sample, and the processed cross-section of the sample formed by processing by the FIB apparatus and / or the laser processing apparatus can be observed by the SEM apparatus.

[0026] The microscope apparatus 1 comprises a sample holder (placement unit) 2, a beam irradiation unit 3, a first microscope unit (microscope unit) 4, a second microscope unit (microscope unit) 5, a cover 7, a chamber 10, and a laser processing apparatus 20. Sample A is placed in the sample holder 2. Sample A is also the object to be processed by the FIB apparatus and the laser processing apparatus 20. The object to be processed by the FIB apparatus and the laser processing apparatus 20 (i.e., the material of sample A) is, for example, copper, iron, alloy, semiconductor material, etc. The sample holder 2 may support sample A without fixing it, as in the case where sample A is simply placed, or it may fix and hold sample A by, for example, attaching it. Here, the sample holder 2 holds sample A. The beam irradiation unit 3 is for irradiating sample A, which is held (placed (hereinafter the same)) in the sample holder 2, with a focused ion beam. Therefore, the beam irradiation unit 3 may include at least the focused ion beam output unit of the FIB apparatus.

[0027] The first microscope unit 4 is for observing sample A held in the sample holder 2. More specifically, the first microscope unit 4 is configured to acquire an image of sample A (observe sample A) by irradiating sample A held in the sample holder 2 with an electron beam and detecting secondary electrons generated in sample A. Therefore, the first microscope unit 4 may be at least a part of a SEM apparatus that includes an electron beam emission unit and an electron beam detection unit.

[0028] The second microscope unit 5, like the first microscope unit 4, is for observing sample A held in the sample holder 2. More specifically, the second microscope unit 5 is capable of obtaining information about the crystal structure of sample A (observing sample A) by irradiating sample A held in the sample holder 2 with an electron beam and detecting the electron beam scattered by sample A. That is, an example of the second microscope unit 5 is a part of a scanning electron microscope (SEM) device that utilizes electron beam backscatter diffraction (EBSD), and may include at least an electron beam emission unit and a detection unit. Note that the microscope device 1 may also include a transmission electron microscope (TEM) device instead of (or in addition to) the SEM device. In this case, the first microscope unit 4 and the second microscope unit 5 may be at least parts of the TEM device.

[0029] The cover 7 is made of a material that transmits the laser light L, which will be described later, and is provided to cover the sample A held in the sample holder 2. As a result, the cover 7 can be positioned at a reference position interposed between the sample holder 2 and the beam irradiation unit 3, the first microscope unit 4, and the second microscope unit 5, and in the optical path of the laser light L. The cover 7 is configured to be movable from the reference position so as not to be interposed between the sample holder 2 and the beam irradiation unit 3, the first microscope unit 4, and the second microscope unit 5.

[0030] Chamber 10 houses a sample holder 2, a beam irradiation unit 3, a first microscope unit 4, a second microscope unit 5, and a cover 7. Chamber 10 has a laser beam L ingress section 11, which is formed in the shape of a window using a material that transmits laser light L. Chamber 10 also has an exhaust section 12 for evacuating the inside of the chamber 10 to reduce the pressure (create a vacuum). Furthermore, another unit 6 for processing or observing the sample A held in the sample holder 2 may be provided inside chamber 10.

[0031] The laser processing apparatus 20 is used to form a processed cross-section on a sample A by irradiating the sample A with laser light L (modulated light Lm and unmodulated light Ln, described later). The laser processing apparatus 20 has a laser output unit 30 and a laser optical system 40. The laser output unit 30 outputs a low-fluence, ultrashort pulse laser light L1 as the laser light L. The pulse width of the laser light L1 output from the laser output unit 30 is, for example, 1 ps or less. Furthermore, the low-fluence of the laser light L1 may mean, for example, that the energy density of the laser light L1 is near the energy density of the processing threshold of sample A, which is determined so that ablation processing occurs when laser processing is performed on sample A. The laser optical system 40 is a laser irradiation unit for irradiating the sample A, which is held in the sample holder 2, with the laser light L1 output from the laser output unit 30. The laser light L1 output from the laser output unit 30 is guided by the laser optical system 40 and injected into the chamber 10 from the incident unit 11.

[0032] Figure 3 shows the polarization direction of the laser light at each stage of the laser optical system shown in Figure 2. Polarization is represented by the vibration direction of the laser electric field. As shown in Figures 2 and 3, the laser optical system 40 includes a collimating lens 41, an output control unit 42, a beam diameter control unit 43, a branching unit 44, a polarization adjustment unit 45, a spatial light modulator 46, a relay optical system 47, a galvanometer mirror (scanning unit) 48, and a lens (focusing unit) 49. The laser light L1 output from the laser output unit 30 has a first polarization direction P1 which is linearly polarized along the X direction shown in the figure (see Figure 3(a)). The collimating lens 41 collimates the laser light L1 output from the laser output unit 30 and emits it.

[0033] The output control unit 42 is, for example, an attenuator, which adjusts the output of the laser light L1 output from the laser output unit 30. The beam diameter control unit 43 is, for example, a beam expander, which adjusts the beam diameter of the laser light L1 output from the laser output unit 30. Thus, the output control unit 42 and the beam diameter control unit 43 are positioned between the spatial light modulator 46 and the laser output unit 30, and function as adjustment units that adjust the output and beam diameter of the laser light L1.

[0034] The branching section 44 is, for example, a polarization beam splitter, which receives the incident laser light L1 emitted from the beam diameter control section 43 and splits it into a laser light L2 with a second polarization direction P2 along the Z direction shown in the figure (see Figure 3(b)) and a laser light L3 with a first polarization direction P1 (see Figure 3(c)). The second polarization direction P2 is linearly polarized along the Z direction shown in the figure and is a polarization direction perpendicular to the first polarization direction P1. For linearly polarized light to be perpendicular to each other means that the polarization directions of each other are within the range of 90° ± 10°.

[0035] The output control unit 42 (attenuator) may also function as a half-wave plate. In this case, the output control unit 42 may adjust the polarization direction of the laser beam L1, and then the splitter 44 (polarizing beam splitter) may split the laser beam L1 into laser beam L2 and laser beam L3. The laser beam L2 is emitted from the splitter 44 toward the beam damper 51. The laser beam L3 is emitted from the splitter 44 toward the polarization adjustment unit 45.

[0036] The polarization adjustment unit 45 includes, for example, a half-wave plate (one example being a half-wave plate). The polarization adjustment unit 45 receives the laser light L3 emitted from the branching unit 44, that is, the laser light L3 output from the laser output unit 30 and having passed through the above-mentioned optical elements, and adjusts the polarization direction of the laser light L3 to a third polarization direction P3. More specifically, the polarization adjustment unit 45 adjusts the polarization direction of the laser light L3 to a third polarization direction P3 such that the laser light L3 includes a first component C1 of the first polarization direction P1 and a second component C2 of the second polarization direction P2 which is orthogonal to the first polarization direction P1, and emits the adjusted laser light L4 (see Figure 3(d)).

[0037] Here, the total electric field of the laser light at each point is the vector sum of the electric fields of its constituent components. Therefore, the sum of the first component C1 in the first polarization direction P1 and the second component C2 in the second polarization direction P2 constitutes the laser light L4 having the third polarization direction P3.

[0038] The spatial light modulator 46 receives the laser light L4 emitted from the polarization adjustment unit 45, modulates the laser light L4, and emits it. Here, the spatial light modulator 46 has a liquid crystal layer, and by displaying a modulation pattern on the liquid crystal layer, the laser light L4 entering and leaving the liquid crystal layer is modulated according to the modulation pattern. As an example, the spatial light modulator 46 is an LCOS-SLM (Liquid Crystal On Silicon - Spatial Light Modulator).

[0039] The spatial light modulator 46 has the characteristic of modulating and emitting light in the first polarization direction P1, while emitting light in the second polarization direction P2 without modulation. Therefore, the spatial light modulator 46 modulates the first component C1 of the laser light L4 in the first polarization direction P1 and emits it as modulated light Lm (see Figure 3(e)), while emitting the second component C2 of the laser light L4 in the second polarization direction P2 as unmodulated light Ln (see Figure 3(f)).

[0040] When the spatial light modulator 46 performs modulation according to a modulation pattern, examples of such modulation patterns include pattern Mp1 for self-correcting the shape distortion of the spatial light modulator 46, as shown in Figure 4(a), and pattern Mp2 for aligning the modulated light Lm with the unmodulated light Ln, which is spatially shifted relative to the modulated light Lm due to the shape distortion of the spatial light modulator 46, as shown in Figure 4(b). The spatial light modulator 46 may also display a pattern composed of superimposing pattern Mp1, pattern Mp2, or other arbitrary patterns.

[0041] Refer to Figure 2 again. The relay optical system 47 includes a pair of lenses 47a and 47b and is used to image the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 onto the entrance pupil of lens 49. Lens 49 receives the modulated light Lm and unmodulated light Ln output from the spatial light modulator 46 via the relay optical system 47 and the galvanometer mirror 48 and focuses them toward sample A, thereby forming an illumination region R on sample A (see Figure 6, etc.). Lens 49 is, for example, an fθ lens.

[0042] The galvano mirror 48 includes mirrors 48a and 48b. By driving these mirrors 48a and 48b, the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 and passing through the relay optical system 47 are irradiated onto the sample A held in the sample holder 2 via the lens 49 while scanning. As described above, the modulated light Lm and unmodulated light Ln are focused by the lens 49 to form an irradiation area R on the sample A. Therefore, the galvano mirror 48 scans this irradiation area R onto the sample A.

[0043] Furthermore, the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 and passing through the relay optical system 47 may have their optical paths adjusted by predetermined mirrors 56 and 57 and then be incident on the galvanometer mirror 48. Alternatively, when scanning the irradiation area R with respect to the sample A, the galvanometer mirror 48 may perform reciprocating processing by repeatedly performing, in sequence, scanning the irradiation area R along the second direction D2 from one side of the second direction D2 to the other, moving the irradiation area R to the first direction D1, scanning the irradiation area R along the second direction D2 from the other side of the second direction D2 to the first, and moving the irradiation area R to the first direction D1. Alternatively, the galvanometer mirror 48 may perform helical processing by repeatedly performing scanning of the irradiation area R along the second direction D2 and scanning of the irradiation area R along the first direction D1 in a helical manner.

[0044] The microscope apparatus 1 described above can process sample A using a focused ion beam from the beam irradiation unit 3, and process sample A using laser light L (modulated light Lm and unmodulated light Ln) from the laser processing apparatus 20. When using a focused ion beam, high-precision processing of sample A is possible. On the other hand, when using laser light L, large-area processing of sample A is possible with high throughput.

[0045] Here, as shown in the conventional example in Figure 5, if sample A is processed using a low-fluence, ultrashort-pulse laser beam L near the processing threshold of sample A, there is a risk that a fine periodic structure, such as a laser-induced periodic surface structure (LIPSS), may be formed on the processed cross-section As of sample A. Since flatness of the processed cross-section As is required for observation with a SEM device, the formation of a fine periodic structure on the processed cross-section As is undesirable. Furthermore, not only from the standpoint of ensuring the flexural strength of sample A, but also from the standpoint of ensuring the flexural strength of sample A, the formation of a fine periodic structure on the processed cross-section As is undesirable. Note that the processed cross-section As is the surface that intersects the processed surface Ar that intersects the optical axis of the laser beam L in sample A (i.e., along the optical axis of the laser beam L). Note that the processed cross-section As being along the optical axis of the laser beam L includes cases where the processed cross-section As is parallel to the laser beam L, and cases where the processed cross-section As is slightly inclined with respect to the optical axis of the laser beam L.

[0046] Furthermore, one hypothesis for the principle of LIPSS formation is that it is due to the interaction between plasma and laser light. The outline of this hypothesis is as follows: When an ultrashort pulse laser beam is irradiated onto a sample, atoms and ions are removed from the sample surface. Once the atoms and ions are removed, a plasma with a shielding effect is generated directly above the point of laser irradiation. As a result, the atoms and ions removed from the sample surface are deposited on the processed surface without being diffused due to the shielding effect of the plasma. Consequently, LIPSS is formed on the processed surface by these deposits.

[0047] In contrast, the laser processing apparatus 20 according to this embodiment is equipped with a configuration that can suppress the generation of a fine periodic structure in the processed cross-section As of sample A. This point will be explained next.

[0048] As described above, the polarization adjustment unit 45 receives the laser light L3 emitted from the branching unit 44, adjusts the polarization direction of the laser light L3, and emits it as the adjusted laser light L4. At this time, the polarization adjustment unit 45 adjusts the polarization direction of the laser light L3 so that the intensity of the first component C1 in the first polarization direction P1 of the laser light L4 is equal to or greater than the intensity of the second component C2 in the second polarization direction P2.

[0049] The lens 49 focuses the modulated light Lm, which has been modulated by the spatial light modulator 46, and the unmodulated light Ln, which has not been modulated by the spatial light modulator 46, from the laser light L4 adjusted by the polarization adjustment unit 45, toward sample A, thereby forming a single continuous irradiation region R on sample A that includes the modulated light Lm and the unmodulated light Ln, as shown in Figure 6. The single continuous irradiation region R that includes the modulated light Lm and the unmodulated light Ln means a state in which at least a part of the first irradiation region R1 of the modulated light Lm in sample A and at least a part of the second irradiation region R2 of the unmodulated light Ln in sample A overlap. Furthermore, the first irradiation region R1 of the modulated light Lm in sample A is the range in sample A where the intensity of the modulated light Lm is 20% or more of the peak, and the second irradiation region R2 of the unmodulated light Ln in sample A is the range in sample A where the intensity of the unmodulated light Ln is 20% or more of the peak. Furthermore, Figure 6(a) is a schematic diagram of sample A as viewed from the optical axis direction (third direction D3) of the modulated light Lm and unmodulated light Ln, and Figure 6(b) is a diagram showing the intensity distribution of the irradiation area R as viewed from the third direction D3.

[0050] In the example shown in Figure 6, the lens 49 forms a single continuous irradiation region R by converging a first irradiation region R1 formed on sample A by converging a modulated light Lm and a second irradiation region R2 formed on sample A by converging an unmodulated light Ln, with these regions coinciding when viewed from a third direction D3. In other words, here, the lens 49 concentrates the modulated light Lm and the unmodulated light Ln in the irradiation region R such that the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln overlap with each other when viewed from a third direction D3. Note that the overlap of the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln means that the region where the intensity of the modulated light Lm is 95% or more of the peak and the region where the intensity of the unmodulated light Ln is 95% or more of the peak overlap with each other.

[0051] Furthermore, the lens 49 focuses the modulated light Lm and unmodulated light Ln in the irradiation area R such that the first polarization direction P1 is aligned with the first direction D1 which intersects the third direction D3, and the second polarization direction P2 is aligned with the second direction D2 which intersects the third direction D3 and the first direction D1. Then, as shown in Figures 6 and 7, the galvanometer mirror 48 scans the irradiation area R with respect to the sample A along the second direction D2, thereby forming a processed cross section As along the second direction D2 on the sample A.

[0052] According to the inventors' findings, when scanning a single continuous irradiation region R formed by focusing modulated light Lm and unmodulated light Ln onto a sample A, if the modulated light Lm (first component C1) has an intensity greater than or equal to the intensity of the unmodulated light Ln (second component C2), and the first polarization direction P1, which is the polarization direction of the modulated light Lm, intersects the scanning direction (second direction D2), while the second polarization direction P2, which is the polarization direction of the unmodulated light Ln, is aligned with the scanning direction, then, as shown in Figure 8, the formation of a microperiodic structure is suppressed in the processed cross section As formed along the scanning direction.

[0053] Next, we will examine this point further. Figure 9 shows the appearance of the processed cross-section when the ratio of the intensity of modulated light (first component) and unmodulated light (second component) is changed. Figures 9(a) to (k) show the processed cross-section As when the ratio of the intensity of the first component C1 (modulated light Lm) to the intensity of the second component C2 (unmodulated light Ln) (hereinafter sometimes referred to as the "intensity ratio") is 100:0, 97:3, 95:5, 88:12, 86:14, 82:18, 73:27, 66:34, 52:48, 15:85, and 0:100, respectively.

[0054] As shown in Figure 9, compared to the case where the intensity ratio in Figure 9(a) is 100:0 (i.e., only the first component C1 is present), it can be seen that when the intensity ratios in Figure 9(b) and (c) are 97:3 and 95:5, the microperiodic structure is reduced, but when the intensity ratio in Figure 9(d) becomes 88:12, the microperiodic structure is significantly reduced.

[0055] On the other hand, while a significant reduction in the fine periodic structure is observed when the intensity ratio changes from 88:12 in Figure 9(d) to 86:14, 82:12, 73:27, 66:34, and 52:48 in Figures 9(e) to (i), no reduction in the fine periodic structure is observed when the intensity ratios in Figures 9(j) and (k) are 15:85 and 0:100 (i.e., when only the second component C2 is present).

[0056] Therefore, when the polarization adjustment unit 45 adjusts the polarization direction of the laser light L3, it is desirable to adjust the polarization direction of the laser light L3 such that the ratio of the intensity of the first component C1 in the first polarization direction P1 of the laser light L4 to the intensity of the second component C2 in the second polarization direction P2 is 50:50 or more and 90:10 or less. Alternatively, the polarization adjustment unit 45 may adjust the polarization direction of the laser light L3 such that the ratio of the intensity of the first component C1 to the intensity of the second component C2 in the laser light L4 is 60:40 or more and 80:20 or less (and even 70:30 or more and 80:20 or less).

[0057] Here, regarding the relationship between the first polarization direction P1 and the second direction D2 (scanning direction) in the irradiation region R, and the relationship between the intensity ratio in the irradiation region R, the following four cases can be considered. Specifically, there are two cases in the irradiation region R where the first polarization direction P1 intersects the second direction D2 (i.e., intersects the processed cross section As) and the first polarization direction P1 follows the second direction D2 (i.e., follows the processed cross section As), and two cases in the irradiation region R where the intensity of the first component C1 is greater than or equal to the intensity of the second component C2 and the intensity of the first component C1 is less than the intensity of the second component C2. These four cases are composed of combinations of these two cases. Therefore, the reduction of the microperiodic structure will be examined for each of these four cases.

[0058] Figure 10 is an SEM image showing a processed cross-section in the irradiated area where the first polarization direction intersects the processed cross-section and the intensity of the first component is greater than or equal to the intensity of the second component. Figures 10(a) to (g) show the cases where the intensity ratios are 52:48, 65:35, 70:30, 74:26, 76:24, 80:20, and 85:15, respectively. Figure 10(h) is an enlarged view of a part of Figure 10(d). As shown in Figure 10, a reduction in the microperiodic structure is observed in this case.

[0059] Figure 11 is an SEM image showing a processed cross-section in the irradiated area where the first polarization direction intersects the processed cross-section and the intensity of the first component is less than the intensity of the second component. Figures 10(a) to (g) show the cases where the intensity ratios are 48:52, 35:65, 30:70, 26:74, 24:76, 20:80, and 15:85, respectively. Figure 11(h) is an enlarged view of a part of Figure 11(e). As shown in Figure 11, in this case, no reduction in the microperiodic structure is observed.

[0060] Figure 12 is an SEM image showing a processed cross-section when the first polarization direction in the irradiated area is aligned with the processed cross-section and the intensity of the first component is greater than or equal to the intensity of the second component. Figures 12(a) to (g) show the cases where the intensity ratios are 52:48, 65:35, 70:30, 74:26, 76:24, 80:20, and 85:15, respectively. Figure 12(h) is an enlarged view of a part of Figure 12(f). As shown in Figure 12, no reduction in the microperiodic structure is observed in this case either.

[0061] Figure 13 is an SEM image showing the processed cross-section when the first polarization direction aligns with the processed cross-section in the irradiated area, and the intensity of the first component is less than the intensity of the second component. Figures 13(a) to (g) show the cases where the intensity ratios are 48:52, 35:65, 30:70, 26:74, 24:76, 20:80, and 15:85, respectively. Figure 13(h) is an enlarged view of a part of Figure 13(g). As shown in Figure 13, no reduction in the microperiodic structure is observed in this case either.

[0062] From the above findings, it can be confirmed that when scanning a single continuous irradiation region R formed by focusing modulated light Lm and unmodulated light Ln onto sample A, the modulated light Lm (first component C1) has an intensity greater than or equal to the intensity of the unmodulated light Ln (second component C2), and the first polarization direction P1, which is the polarization direction of the modulated light Lm, intersects the scanning direction (second direction D2, i.e., the processed cross section As), thereby suppressing the formation of a microperiodic structure in the processed cross section As.

[0063] Next, the laser processing method according to this embodiment will be described. The laser processing method according to this embodiment is a laser processing method for forming a processed cross section As on a sample A by irradiating the sample A with laser light L (modulated light Lm and unmodulated light Ln). The laser processing method according to this embodiment includes a step S101 (polarization adjustment step) in which the polarization direction of the laser light L3 having a pulse width of 1 ps or less includes a first component C1 in a first polarization direction P1 and a second component C2 in a second polarization direction P2 that is orthogonal to the first polarization direction P1, and generates the adjusted laser light L4 (see Figures 2 and 3).

[0064] Furthermore, the laser processing method according to this embodiment includes a step S102 (modulation step) in which the laser light L4 generated in step S101 is incident on a spatial light modulator 46, the first component C1 of the laser light L4 is modulated by the spatial light modulator 46 and emitted from the spatial light modulator 46 as modulated light Lm, and the second component C2 of the laser light L4 is emitted from the spatial light modulator 46 as unmodulated light Ln (see Figures 2 and 3).

[0065] Furthermore, the laser processing method according to this embodiment includes a step S103 (focusing step) of focusing the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 toward the sample A to form a single continuous irradiation region R including the modulated light Lm and unmodulated light Ln on the sample A, and a step S104 (scanning step) of scanning the irradiation region R with respect to the sample A (see Figures 6 and 7).

[0066] In step S101, the polarization direction of the laser beam L4 is adjusted so that the intensity of the first component C1 in the laser beam L4 is greater than or equal to the intensity of the second component C2. In step S103, the modulated light Lm and unmodulated light Ln are focused in the irradiation area R so that the first polarization direction P1 is aligned with the first direction D1 and the second polarization direction P2 is aligned with the second direction D2 (see Figure 6). Then, in step S104, the irradiation area R is scanned along the second direction D2 with respect to the sample A to form a processed cross section As aligned with the second direction D2 on the sample A (see Figures 6 and 7). Even with the above laser processing method, the formation of a fine periodic structure in the processed cross section As is suppressed for the reasons mentioned above.

[0067] As described above, in the laser processing apparatus 20 and laser processing method according to this embodiment, a processed cross section As is formed on sample A by irradiating sample A with laser light L (modulated light Lm and unmodulated light Ln). The laser light L is an ultrashort pulse laser having a pulse width of 1 ps or less. Therefore, it is possible to suppress the deterioration of the quality of the processed cross section As caused by changes in the properties of the processed cross section As due to the effects of heat. Furthermore, in the laser processing apparatus 20 and laser processing method according to this embodiment, it is also possible to suppress the deterioration of the quality of the processed cross section As caused by the formation of a fine periodic structure on the processed cross section As by using an ultrashort pulse laser, as described below.

[0068] In other words, in the laser processing apparatus 20 and laser processing method according to this embodiment, the polarization direction of the laser beam L4 is adjusted so that the laser beam L includes a first component C1 in a first polarization direction P1 and a second component C2 in a second polarization direction P2 that is orthogonal to the first polarization direction P1. At this time, the polarization direction of the laser beam L3 is adjusted so that the intensity of the first component C1 in the laser beam L4 is equal to or greater than the intensity of the second component C2. Furthermore, the spatial light modulator 46 modulates the first component C1 of the laser beam L4 after the polarization direction adjustment and emits it as modulated light Lm, while emitting the second component C2 of the laser beam L4 after the polarization direction adjustment as unmodulated light Ln (without modulation).

[0069] Furthermore, by focusing the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 46 toward sample A, a single continuous irradiation region R including the modulated light Lm and unmodulated light Ln is formed on sample A. At this time, in the irradiation region R, the modulated light Lm and unmodulated light Ln are focused such that the first polarization direction P1 is along the first direction D1 which intersects the optical axis direction of the modulated light Lm (third direction D3), and the second polarization direction P2 is along the second direction D2 which intersects the third direction D3 and the first direction D1. Then, by scanning the irradiation region R toward sample A along the second direction D2, a processed cross section As along the second direction D2 is formed on sample A.

[0070] As a result, as shown in the above findings, the formation of a fine periodic structure in the processed cross-section As is suppressed. Therefore, the laser processing apparatus 20 and laser processing method according to this embodiment can suppress the deterioration of the quality of the processed cross-section As.

[0071] Furthermore, in the laser processing apparatus 20 according to this embodiment, the spatial light modulator 46 includes a liquid crystal layer and modulates the first component C1 according to the modulation pattern displayed on the liquid crystal layer. By adjusting the modulation pattern displayed on the liquid crystal layer of the spatial light modulator 46 in this way, it becomes possible to easily perform various modulations, such as self-correcting the shape distortion of the spatial light modulator 46 according to pattern Mp1, or adjusting the modulated light Lm to the unmodulated light Ln that has been spatially shifted due to the shape distortion according to pattern Mp2.

[0072] Furthermore, in the laser processing apparatus 20 according to this embodiment, the polarization adjustment unit 45 can adjust the polarization direction of the laser beam L3 so that the ratio of the intensity of the first component C1 to the intensity of the second component C2 in the laser beam L4 is 50:50 or more and 90:10 or less. In this case, the formation of a microperiodic structure in the processed cross section As can be further suppressed.

[0073] Furthermore, in the laser processing apparatus 20 according to this embodiment, the lens 49 focuses the modulated light Lm and the unmodulated light Ln such that the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln overlap with each other in the irradiation area R. Therefore, the formation of a fine periodic structure in the processed cross section As can be suppressed more reliably.

[0074] Furthermore, in the laser processing apparatus 20 according to this embodiment, the polarization adjustment unit 45 includes a half-wave plate. Therefore, by adjusting the half-wave plate, it becomes possible to easily control the polarization direction of the laser beam L3.

[0075] Furthermore, the microscope apparatus 1 according to this embodiment comprises the laser processing apparatus 20 described above, and a first microscope unit 4 and a second microscope unit 5 for observing the processed cross-section As. As a result, the deterioration of the quality of the processed cross-section As is suppressed, making it possible to obtain highly accurate observation results of the processed cross-section As.

[0076] The above embodiments describe one embodiment of the present invention. Therefore, the present invention can be modified without being limited to the above embodiments. Modifications will be described next.

[0077] In the above embodiment, an example was described in which the lens 49 focuses the modulated light Lm and the unmodulated light Ln such that the peak position Tm of the modulated light Lm's intensity and the peak position Tn of the unmodulated light Ln's intensity overlap in the irradiation region R. However, the lens 49 may also focus the modulated light Lm and the unmodulated light Ln such that the peak position Tm of the modulated light Lm's intensity and the peak position Tn of the unmodulated light Ln's intensity do not overlap in the irradiation region R.

[0078] Figure 14 shows the intensity distribution of modulated and unmodulated light and the processed cross-section according to a modified example. Figure 14(a) shows the intensity distribution of the irradiation region R when the modulated light Lm and unmodulated light Ln are focused so that the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln do not overlap. Figure 14(b) is an SEM image showing the processed cross-section As formed by scanning the irradiation region R having the said intensity distribution.

[0079] As shown in Figure 14, in this case, the modulated light Lm and unmodulated light Ln are focused in such a way that the distance Dp between the peak intensity position Tm of the modulated light Lm and the peak intensity position Tn of the unmodulated light Ln is 80% or less of the diameter Dm of the first irradiation region R1 formed by the focusing of the modulated light Lm, within the range in which a single continuous irradiation region R is formed including the modulated light Lm and the unmodulated light Ln. For example, the distance Dp is about 8 μm and the diameter Dm is about 10 μm. In particular, in this case, in the irradiation region R, the peak intensity position Tn of the unmodulated light Ln is shifted toward the processed cross section As side relative to the peak intensity position Tm of the modulated light Lm. Even in this case, the formation of a microperiodic structure in the processed cross section As is sufficiently suppressed.

[0080] Figure 15 shows the intensity distribution of modulated and unmodulated light and the processed cross-section for a comparative example. Figure 15(a) shows the intensity distribution of the irradiation region R when the modulated light Lm and unmodulated light Ln are focused so that the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln do not overlap. Figure 15(b) is an SEM image showing the processed cross-section As formed by scanning the irradiation region R having the said intensity distribution.

[0081] As shown in Figure 15, the modulated light Lm and unmodulated light Ln are focused in such a way that the distance Dp between the peak intensity position Tm of the modulated light Lm and the peak intensity position Tn of the unmodulated light Ln is greater than 80% of the diameter Dm of the first irradiation region R1 formed by the focusing of the modulated light Lm. For example, the distance Dp is about 12 μm and the diameter Dm is about 10 μm. In this case, the formation of a microperiodic structure in the processed cross section As is not sufficiently suppressed.

[0082] From at least the above viewpoint, the lens 49 can focus the modulated light Lm and the unmodulated light Ln such that, in the irradiation region R, the distance Dp between the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln is 80% or less of the diameter Dm of the first irradiation region R1 formed by the focusing of the modulated light Lm. Furthermore, the lens 49 can focus the modulated light Lm and the unmodulated light Ln such that, in the irradiation region R, the peak position Tn of the intensity of the unmodulated light Ln is shifted toward the processed cross-section As side relative to the peak position Tm of the intensity of the modulated light Lm. Moreover, the lens 49 can focus the modulated light Lm and the unmodulated light Ln such that, in the irradiation region R, the peak position Tm of the intensity of the modulated light Lm and the peak position Tn of the intensity of the unmodulated light Ln overlap each other at least partially.

[0083] Furthermore, in the above embodiment, a spatial light modulator 46 having a liquid crystal layer was exemplified as a means for generating modulated light Lm and unmodulated light Ln from the laser light L4 emitted from the polarization adjustment unit 45. However, in the laser processing apparatus 20, a spatial light modulator 70 shown in Figure 16 may be used instead of the spatial light modulator 46. The spatial light modulator 70 includes a pair of polarizing beam splitters 71, 74 and a pair of mirrors 72, 73 interposed between the polarizing beam splitters 71, 74.

[0084] The polarizing beam splitter 71 receives the laser light L4 emitted from the polarization adjustment unit 45, reflects the first component C1 of the laser light L4 in the first polarization direction P1 toward the mirror 72 as modulated light Lm, and transmits the second component C2 of the laser light L4 in the second polarization direction P2 toward the polarizing beam splitter 74 as unmodulated light Ln. The mirror 72 reflects the modulated light Lm emitted from the polarizing beam splitter 71 toward the mirror 73. The mirror 73 reflects the modulated light Lm from the mirror 72 toward the polarizing beam splitter 74.

[0085] The polarizing beam splitter 74 receives the modulated light Lm incident from the mirror 73, reflects the modulated light Lm and emits it in a direction different from the incident direction, and also emits the unmodulated light Ln that has passed through the polarizing beam splitter 71. At this time, the optical axis of the modulated light Lm and the optical axis of the unmodulated light Ln are aligned. The modulated light Lm and unmodulated light Ln emitted from the polarizing beam splitter 74 are emitted from the spatial light modulator 70. As a result, the lens 49 can focus the modulated light Lm and unmodulated light Ln emitted from the spatial light modulator 70 toward the sample A and form an illumination region R.

[0086] Furthermore, in the above embodiment, the polarization adjustment unit 45 was exemplified as including a half-wave plate (i.e., being a half-wave plate). However, the polarization adjustment unit 45 may include a rotator or a liquid crystal modulation element instead of (or in addition to) the half-wave plate.

[0087] Furthermore, the laser processing apparatus 20 according to the above embodiment may further include a wavelength conversion unit positioned downstream of the laser output unit 30 and upstream of the collimating lens 41, on the optical path of the laser beam L1. The wavelength conversion unit receives the incident laser beam L1 output from the laser output unit 30 and converts the wavelength of the laser beam L1 before outputting it. By using the wavelength conversion unit, for example, it is possible to shorten the wavelength of the laser beam L1 to enable finer processing, or to select the optimal wavelength for the material of sample A.

[0088] Furthermore, the laser processing apparatus 20 according to the above embodiment may have a control unit 60 that adjusts the ratio of the intensity of the first component C1 to the intensity of the second component C2 in the laser light L4 by controlling, for example, a half-wave plate of the polarization adjustment unit 45. In this case, the control unit 60 may further adjust the modulation pattern used for modulating the first component C1 by controlling the spatial light modulator 46. The control unit 60 may be configured as a computer device including, for example, a processor, memory, storage, and communication devices. In addition, the control unit 60 may perform various processes for controlling each part such as the polarization adjustment unit 45 and the spatial light modulator 46 by having the processor execute software (programs) loaded into the memory, etc., and controlling the reading and writing of data in the memory and storage, as well as communication by the communication device. Furthermore, the laser processing apparatus 20 does not have to be incorporated into the microscope device 1. [Explanation of Symbols]

[0089] 1...Microscope device, 20...Laser processing device, 30...Laser output unit, 45...Polarization adjustment unit, 46...Spatial light modulator, 48...Galvanometer mirror (scanning unit), 49...Lens (light focusing unit), A...Sample (object), As...Processed cross-section, C1...First component, C2...Second component, L,L1,L3,L4...Laser light, Lm...Modulated light, Ln...Unmodulated light, P1...First polarization direction, P2...Second polarization direction, R...Irradiation area, R1...First irradiation area, R2...Second irradiation area, Tm,Tn...Peak position.

Claims

1. A laser processing apparatus for forming a processed cross-section on an object by irradiating the object with laser light, A laser output unit for outputting laser light having a pulse width of 1 ps or less, A polarization adjustment unit receives the incident laser light output from the laser output unit, adjusts the polarization direction of the laser light so that the laser light includes a first component in a first polarization direction and a second component in a second polarization direction perpendicular to the first polarization direction, and emits the adjusted laser light. A spatial light modulator that receives the laser light emitted from the polarization adjustment unit, modulates the first component of the laser light and emits it as modulated light, and emits the second component of the laser light as unmodulated light, A focusing unit that focuses the modulated light and unmodulated light emitted from the spatial light modulator toward the object, thereby forming a single continuous illumination area on the object that includes the modulated light and the unmodulated light, A scanning unit for scanning the irradiation area with respect to the object, Equipped with, The polarization adjustment unit adjusts the polarization direction of the laser light so that the intensity of the first component in the laser light is equal to or greater than the intensity of the second component. The light-gathering unit focuses the modulated light and the unmodulated light in the irradiation area such that the first polarization direction is along a first direction intersecting the optical axis direction of the modulated light, and the second polarization direction is along a second direction intersecting the optical axis direction and the first direction. The scanning unit scans the irradiation area with respect to the object along the second direction, thereby forming the processed cross-section along the second direction on the object. Laser processing equipment.

2. The spatial light modulator includes a liquid crystal layer and modulates the first component according to a modulation pattern displayed on the liquid crystal layer. The laser processing apparatus according to claim 1.

3. The polarization adjustment unit adjusts the polarization direction of the laser light so that the ratio of the intensity of the first component to the intensity of the second component in the laser light is 50:50 or more and 90:10 or less. The laser processing apparatus according to claim 1.

4. The light-gathering unit focuses the modulated light and the unmodulated light such that the distance between the peak position of the intensity of the modulated light and the peak position of the intensity of the unmodulated light in the irradiation area is 80% or less of the diameter of the first irradiation area formed by the focusing of the modulated light. The laser processing apparatus according to claim 1.

5. The light-gathering unit focuses the modulated light and the unmodulated light in the irradiation area such that the peak position of the intensity of the modulated light and the peak position of the intensity of the unmodulated light overlap at least partially with each other. The laser processing apparatus according to claim 4.

6. The light-gathering unit focuses the modulated light and the unmodulated light in the irradiation area such that the peak intensity of the unmodulated light is shifted toward the processed cross-section side relative to the peak intensity of the modulated light. The laser processing apparatus according to claim 4.

7. The polarization adjustment unit includes a half-wave plate, The laser processing apparatus according to claim 1.

8. A laser processing apparatus according to any one of claims 1 to 7, A microscope unit for observing the processed cross-section, A microscope device equipped with the following features.

9. A laser processing method for forming a processed cross-section on an object by irradiating the object with laser light, A polarization adjustment step involves adjusting the polarization direction of a laser beam having a pulse width of 1 ps or less so that it includes a first component in a first polarization direction and a second component in a second polarization direction perpendicular to the first polarization direction, thereby generating the adjusted laser beam. A modulation step is to inject the laser light generated in the polarization adjustment step into a spatial light modulator, modulate the first component of the laser light with the spatial light modulator and emit it from the spatial light modulator as modulated light, and emit the second component of the laser light from the spatial light modulator as unmodulated light, A focusing step of focusing the modulated light and the unmodulated light emitted from the spatial light modulator toward the object, thereby forming a single continuous illumination region on the object that includes the modulated light and the unmodulated light, A scanning step of scanning the irradiation area with respect to the object, Equipped with, In the polarization adjustment step, the polarization direction of the laser light is adjusted so that the intensity of the first component in the laser light is equal to or greater than the intensity of the second component. In the focusing step, the modulated light and the unmodulated light are focused in the irradiation area such that the first polarization direction is along a first direction intersecting the optical axis direction of the modulated light, and the second polarization direction is along a second direction intersecting the optical axis direction and the first direction. In the scanning step, the irradiation area is scanned with respect to the object along the second direction to form the processed cross-section along the second direction on the object. Laser processing method.

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