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 decrease in transmittance of a transparent material. [Solution] The laser processing apparatus 20 includes a sample holder 2 on which a sample A is placed, a laser optical system 40 for irradiating with a first laser beam L1 and a second laser beam L2, and a cover 7 positioned between the sample A placed in the sample holder 2 and the laser optical system 40, which is on the optical axis of the first laser beam L1 and the second laser beam L2 and transmits the first laser beam L1 and the second laser beam L2. The laser optical system 40 includes a lens 48 that focuses the first laser beam L1 to form a first focal point P1 of the first laser beam L1 at a first position Z1 on the sample A side of the cover 7, and forms a first irradiation area R1 of the first laser beam L1 on the incident surface Ai of 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 processing object is held in a vacuum chamber. The vacuum chamber is provided with a window that transmits a laser beam. Then, the laser beam emitted from a laser light source is made to enter the processing object through the window. As a result, an etching phenomenon called ablation occurs on the surface of the processing object, and the surface of the processing object is supposed to be shaved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need to perform ablation processing of a sample by irradiating the sample with laser light through a transmission member such as a window of a vacuum chamber as in the laser processing method described in Patent Document 1 above. When performing ablation processing of the sample, particles may be generated from the sample and adhere to the transmission member. If ablation processing is continued in a situation where particles adhere to the transmission member, the transmittance of the laser light of the transmission member may decrease, resulting in a decrease in processing quality or an unintended absorption of laser light in the transmission member, which may cause the transmission member to break.

[0005] An object of the present invention is to provide a laser processing apparatus, a microscope apparatus, and a laser processing method capable of suppressing a decrease in the transmittance of a transmission member.

Means for Solving the Problems

[0006] The laser processing apparatus according to the present invention comprises: [1] a placement section on which an object is placed; a laser irradiation section for irradiating a first laser beam and a second laser beam; and a transparent member positioned between the object placed in the placement section and the laser irradiation section, on the optical axes of the first laser beam and the second laser beam, and transmitting the first laser beam and the second laser beam. The laser irradiation section focuses the first laser beam to form a first focusing point of the first laser beam at a first position closer to the object than the transparent member, and forms a passing region through which the first laser beam passes on the object-side surface of the transparent member, while forming a first irradiation region of the first laser beam on the incident surface of the first laser beam on the object. The laser processing apparatus comprises a focusing unit for focusing the second laser beam to form a second focusing point of the second laser beam at a second position closer to the transparent member than the first position, and for forming a second irradiation area of ​​the second laser beam on the surface of the transparent member on the object side, and a scanning unit for scanning the first irradiation area and the second irradiation area to perform ablation processing of the object with the first laser beam and ablation processing of particles generated by the ablation processing of the object with the second laser beam, and the incident surface is inclined with respect to the optical axis of the first laser beam such that the normal of the incident surface in the first irradiation area reaches outside the passing area.

[0007] The laser processing method according to the present invention is a laser processing method using a laser processing apparatus having:

[10] "a placement section on which an object is placed; a laser irradiation section for irradiating a first laser beam and a second laser beam; and a transparent member positioned between the object placed in the placement section and the laser irradiation section, on the optical axes of the first laser beam and the second laser beam, which transmits the first laser beam and the second laser beam, wherein by focusing the first laser beam, a first focusing point of the first laser beam is formed at a first position on the object side of the transparent member, and a passing region is formed on the object side surface of the transparent member through which the first laser beam passes, and a first irradiation region of the first laser beam is formed on the incident surface of the first laser beam of the object The laser processing method comprises: a focusing step for forming a region and focusing the second laser beam to form a second focusing point of the second laser beam at a second position on the side of the transmissive member closer to the first position, and for forming a second irradiation region of the second laser beam on the surface of the transmissive member on the object side; and a scanning step for scanning the first irradiation region and the second irradiation region to perform ablation processing of the object with the first laser beam and ablation processing of particles generated by the ablation processing of the object with the second laser beam, wherein the incident surface is inclined with respect to the optical axis of the first laser beam such that the normal of the incident surface in the first irradiation region reaches outside the passing region.

[0008] In this laser processing apparatus and laser processing method, when the first laser beam is focused, a first focal point of the first laser beam is formed at a first position on the object side of the transparent member, and a passage region is formed on the object-side surface of the transparent member through which the first laser beam passes, while a first irradiation region of the first laser beam is formed on the incident surface of the first laser beam on the object. When the second laser beam is focused, a second focal point of the second laser beam is formed at a second position on the object-side of the transparent member, and a second irradiation region of the second laser beam is formed on the object-side surface of the transparent member. Then, by scanning the first and second irradiation regions, ablation processing of the object is performed using the first laser beam, and ablation processing of particles generated by the ablation processing of the object is performed using the second laser beam. Therefore, particles adhering to the transparent member can be removed. Thus, a decrease in the transmittance of the transparent member is suppressed.

[0009] In particular, in this laser processing apparatus and laser processing method, the incident surface of the first laser beam on the object is tilted with respect to the optical axis of the first laser beam L such that the normal to the incident surface in the first irradiation region reaches outside the passage region (the region on the surface of the transparent member through which the first laser beam passes). When the first laser beam is irradiated onto the object, more particles are scattered in the direction of the normal to the incident surface of the first laser beam on the object than in other directions. Therefore, the amount of particles adhering to the passage region on the surface of the transparent member through which the first laser beam passes is reduced, and the decrease in transmittance is more reliably suppressed.

[0010] The laser processing apparatus according to the present invention may also be [2] "the laser processing apparatus according to [1] above, wherein the arrangement portion includes an arrangement surface on which the object is arranged such that the incident surface is inclined with respect to the optical axis of the first laser beam." In this way, when inclining the incident surface with respect to the optical axis of the first laser beam such that the normal to the incident surface reaches outside the passing region, the elements on the arrangement portion side on which the object is arranged (arrangement surface) may contribute.

[0011] The laser processing apparatus according to the present invention may also be [3] "the laser processing apparatus according to [2] above, wherein the arrangement unit further includes an angle adjustment unit for adjusting the angle of the arrangement surface." In this case, the angle of the arrangement surface becomes adjustable.

[0012] 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 laser irradiation unit further includes an optical axis adjustment unit that tilts the optical axis of the first laser beam with respect to the normal of the incident surface." In this way, the element on the laser irradiation unit side (optical axis adjustment unit) may contribute to tilting the incident surface with respect to the optical axis of the first laser beam so that the normal of the incident surface reaches outside the passing region.

[0013] The laser processing apparatus according to the present invention may also be [5] "a laser processing apparatus according to any one of [1] to [4] above, further comprising a housing for housing the arrangement portion, wherein a recess for collecting the particles is formed on the inner surface of the housing portion at a portion of the normal to the housing portion." In this case, by collecting particles in the recess of the housing portion, the amount of particles adhering to the surface of the transparent member can be reduced, and the reduction in the transmittance of the transparent member can be suppressed more reliably.

[0014] The laser processing apparatus according to the present invention may also be [6] "the laser processing apparatus according to [5] above, wherein, in the direction of the optical axis of the first laser beam, the distance from the object to the bottom surface of the recess is greater than the distance from the object to the transparent member." In this case, the adhesion of particles reflected from the bottom surface of the recess to the transparent member is reduced.

[0015] The laser processing apparatus according to the present invention may also be [7] "a laser processing apparatus according to any one of [1] to [6] above, further comprising a housing for housing the arrangement portion, wherein a collection area is provided on the inner surface of the housing portion, in the portion where the normal to the housing portion reaches, made of a material to which particles are more likely to adhere than to the inner surface." In this case, by collecting particles in the repair area of ​​the housing portion, the amount of particles adhering to the surface of the transparent member can be reduced, and the reduction in the transmittance of the transparent member can be suppressed more reliably.

[0016] The laser processing apparatus according to the present invention may also be [8] "the laser processing apparatus according to any one of [1] to [7] above, wherein the incident surface is inclined with respect to the optical axis of the first laser beam such that the normal extends outside the range in which the passing region can be formed by scanning the first irradiation region on the surface." In this case, particles adhering to the surface of the transparent member can be reduced more reliably.

[0017] The laser processing apparatus according to the present invention may also be [9] "the laser processing apparatus according to any one of [1] to [8] above, wherein the incident surface is inclined with respect to the optical axis of the first laser beam such that the normal reaches the outside of the transparent member." In this case, particles adhering to the surface of the transparent member can be reduced more reliably.

[0018] The microscope apparatus according to the present invention may also be

[10] "a microscope apparatus comprising a laser processing apparatus described in any of [1] to [9] above, and a microscope unit for observing the processed cross-section formed on the object by ablation processing with the first laser beam." Since this microscope apparatus is equipped with the above-mentioned laser processing apparatus, it is possible to suppress the reduction in the transmittance of the transparent member and to observe the processed cross-section of the object. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a laser processing apparatus, a microscope apparatus, and a laser processing method that can suppress the decrease in transmittance of a transparent member.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram showing a part of the microscope apparatus according to the present embodiment. [Figure 2] It is a schematic diagram showing the remaining part of the microscope apparatus shown in FIG. 1. [Figure 3] It is a diagram for explaining the laser processing according to the comparative example. [Figure 4] It is a diagram for explaining the laser processing according to the first embodiment. [Figure 5] It is a diagram for explaining the laser processing according to the first embodiment. [Figure 6] It is a diagram for explaining the laser processing according to the first embodiment. [Figure 7] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 8] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 9] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 10] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 11] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 12] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 13] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 14] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 15] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 16] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 17] It is a diagram for explaining a modified example of the laser processing according to the first embodiment. [Figure 18] This figure illustrates a modified example of laser processing according to the first embodiment. [Figure 19] This figure illustrates a modified example of laser processing according to the first embodiment. [Figure 20] This figure illustrates a modified example of laser processing according to the first embodiment. [Figure 21] This figure illustrates a modified example of laser processing according to the first embodiment. [Figure 22] This is a flowchart showing an example of a laser processing method according to the first embodiment. [Figure 23] Figure 22 is a flowchart showing the specific steps of process S102. [Figure 24] This is a diagram illustrating laser processing according to the second embodiment. [Figure 25] This figure illustrates a modified example of laser processing according to the second embodiment. [Figure 26] This figure shows a microscope apparatus related to a modified example. [Modes for carrying out the invention]

[0021] 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. [First Embodiment]

[0022] Figure 1 is a schematic diagram showing a part of the microscope apparatus according to this embodiment. Figure 2 is a schematic diagram showing the remaining part of the microscope apparatus shown in Figure 1. 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 of 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 (in this case, ablation processing) of the sample, and the processed cross-section of the sample formed by processing by the FIB apparatus and / or the laser apparatus can be observed by the SEM apparatus.

[0023] The microscope apparatus 1 comprises a sample holder 2 (placement section), a beam irradiation section (not shown), a microscope section 4, a sample chamber 6 (storage section), a cover 7 (transmissive member), a chamber 10, and a laser processing apparatus 20. A sample A (object) is placed in the sample holder 2. The sample holder 2 may support the sample A without fixing it, as in the case where the sample A is simply placed, or it may fix and hold the sample A by means of adhesive, for example. Here, the sample holder 2 holds the sample A. The beam irradiation section is for irradiating the sample A held (placed (hereinafter the same)) in the sample holder 2 with a focused ion beam. Therefore, the beam irradiation section may include at least the focused ion beam output section of the FIB apparatus.

[0024] The microscope unit 4 is for observing sample A held in the sample holder 2. More specifically, the 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 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.

[0025] The microscope device 1 may also include a separate microscope unit (not shown) from the microscope unit 4. In this case, the separate microscope unit, like the microscope unit 4, is for observing the sample A held in the sample holder 2. More specifically, the separate microscope unit 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 separate microscope unit is a part of a scanning electron microscope (SEM) device using electron backscatter diffraction (EBSD), and may include at least an electron beam emission unit and a detection unit. 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 microscope unit 4 and the separate microscope unit may be at least part of the TEM device.

[0026] The sample chamber 6 houses the sample holder 2 and the sample A placed in the sample holder 2. The cover 7 is made of a material that transmits the laser light L, which will be described later, and is provided between the sample A held in the sample holder 2 and the laser irradiation unit 3. More specifically, the cover 7 is provided on the wall of the sample chamber 6 facing the laser irradiation unit 3 and constitutes the incident part for the laser light L into the sample chamber 6. The cover 7 is formed in the shape of a flat plate, for example. That is, the cover 7 is positioned between the sample A placed in the sample holder 2 and the laser optical system 40, which will be described later, on the optical axes of the first laser light L1 and the second laser light L2, which will be described later, and transmits the first laser light L1 and the second laser light L2. The cover 7 may be configured to be movable so as not to be interposed on the observation axis of the microscope unit 4.

[0027] Chamber 10 houses a sample holder 2, a beam irradiation unit, a microscope unit 4, and a sample chamber 6. 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 may be provided inside the chamber 10 for processing or observing the sample A held in the sample holder 2.

[0028] The laser processing apparatus 20 includes a laser output unit 30 and a laser optical system 40. The laser output unit 30 is for outputting a low-fluence, ultrashort-pulse laser beam L. The pulse width of the laser beam L output from the laser output unit 30 is, for example, 1 ps or less. Furthermore, a low-fluence laser beam L may, for example, be defined as having an energy density near the processing threshold of sample A, which is set so that ablation processing occurs when laser processing is performed on sample A. The laser optical system 40 is for irradiating sample A and cover 7, held in sample holder 2, with the laser beam L (first laser beam L1 and second laser beam L2, described later) output from the laser output unit 30. The laser beam L output from the laser output unit 30 is guided by the laser optical system 40, injected into the chamber 10 from the injection unit 11, and then injected into the sample chamber 6 from the cover 7 (in Figure 2, the chamber 10 and injection unit 11 are omitted).

[0029] The laser optical system 40 includes a collimating lens 41, an output control unit 42, a beam diameter control unit 43, a polarization adjustment unit 44, a spatial light modulator 45, a relay optical system 46, a galvanometer mirror (scanning unit) 47, and a lens (focusing unit) 48. The collimating lens 41 collimates the laser light L output from the laser output unit 30 and emits it.

[0030] The output control unit 42 is, for example, an attenuator, which adjusts the output of the laser light L 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 L 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 45 and the laser output unit 30, and function as adjustment units that adjust the output and beam diameter of the laser light L.

[0031] The polarization adjustment unit 44 includes, for example, a half-wave plate (one example being a half-wave plate). The polarization adjustment unit 44 receives the incident laser light L emitted from the beam diameter control unit 43 and adjusts the polarization direction of the laser light L.

[0032] The spatial light modulator 45 receives the laser light L emitted from the polarization adjustment unit 44 and modulates the laser light L. As a result, the spatial light modulator 45 splits the laser light L to generate and emit a first laser beam L1 and a second laser beam L2. Here, the spatial light modulator 45 has a liquid crystal layer, and by displaying a modulation pattern on the liquid crystal layer, it modulates the laser light L entering and leaving the liquid crystal layer according to the modulation pattern. As an example, the spatial light modulator 45 is an LCOS-SLM (Liquid Crystal On Silicon - Spatial Light Modulator).

[0033] The relay optical system 46 includes a pair of lenses 46a and 46b, and is used to transfer the images of the first laser beam L1 and the second laser beam L2 emitted from the spatial light modulator 45 onto the lens 48. The lens 48 receives the first laser beam L1 and the second laser beam L2 output from the spatial light modulator 45 via the relay optical system 46 and the galvanometer mirror 47. The lens 48 focuses the first laser beam L1 toward the sample A to form a first irradiation region R1 on the sample A, and focuses the second laser beam L2 toward the cover 7 to form a second irradiation region R2 on the cover 7 (see Figure 4, etc.). The lens 48 is, for example, an fθ lens.

[0034] The galvano mirror 47 includes mirrors 47a and 47b. By driving these mirrors 47a and 47b, the first laser beam L1 and the second laser beam L2, emitted from the spatial light modulator 45 and passing through the relay optical system 46, are irradiated onto the sample A held in the sample holder 2 via the lens 48 while scanning. As described above, the first laser beam L1 and the second laser beam L2 are focused by the lens 48 to form the first irradiation region R1 and the second irradiation region R2. Therefore, the galvano mirror 47 scans the first irradiation region R1 onto the sample A and the second irradiation region R2 onto the cover 7. This allows for ablation of the sample A by the first laser beam L1, and also ablation of particles adhering to the cover 7 (e.g., particles generated by the ablation of the sample A) by the second laser beam L2. As a result, it becomes possible to ablate the sample A while removing particles adhering to the cover 7.

[0035] Figure 3 is a diagram illustrating laser processing according to a comparative example. In the example shown in Figure 3, the lens 48 focuses the laser beam L to form a first focal point Pp and a first irradiation region Rp on the incident surface Ai of the sample A. The lens 48 also focuses the second laser beam Lc to form a second focal point Pc and a second irradiation region Rc on the surface 7s of the cover 7 on the sample A side. In particular, here the first focal point Pp and the second focal point Pc are aligned in the optical axis direction (Z axis direction) of the laser beam L. That is, here, when viewed from the Z axis direction, the entire region where the intensity in the second irradiation region Rc peaks overlaps with the region where the intensity in the first irradiation region Rp peaks. The region where the intensity in the irradiation region peaks is, for example, the region from the focal point to where the intensity is 80% of the intensity at the focal point.

[0036] In this case, the removal of particles Rt attached to the surface 7s of the cover 7 by ablation processing with the second laser beam Lc and the ablation processing of sample A by laser beam L are performed simultaneously along the Z-axis. Therefore, in this case, since the laser beam L is irradiated while the transmittance of the cover 7 is improved, the decrease in processing quality and processing efficiency is suppressed compared to the case in which the particles Rt attached to the surface 7s of the cover 7 are not removed. On the other hand, in this case, there is a need to more effectively remove the particles Rt attached to the surface 7s of the cover 7.

[0037] As shown in Figures 4 and 5, in this embodiment, the lens 48 focuses the first laser beam L1 to form a first focal point P1 of the first laser beam L1 at a first position Z1 on the sample A side of the cover 7, and also forms a first irradiation region R1 of the first laser beam L1 on the incident surface Ai of the sample A. The lens 48 also focuses the second laser beam L2 to form a second focal point P2 of the second laser beam L2 at a second position Z2 on the cover 7 side of the first position Z1, and also forms a second irradiation region R2 of the second laser beam L2 on the surface 7s of the cover 7 on the sample A side.

[0038] At this time, the lens 48 focuses the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction (Z-axis direction) of the first laser beam L1, at least a portion of the region Rp2 where the intensity in the second irradiation region R2 is at its peak is located outside the region Rp1 where the intensity in the first irradiation region R1 is at its peak. Here, the lens 48 focuses the first laser beam L1 and the second laser beam L2 such that, when viewed from the Z-axis direction, the entire region Rp2 where the intensity in the second irradiation region R2 is at its peak is located outside the region Rp1 where the intensity in the first irradiation region R1 is at its peak. In the illustrated example, the entire second irradiation region R2 (for example, the beam spot of the second laser beam L2 on surface 7s) is located outside the first irradiation region R1 (for example, the beam spot of the first laser beam L1 on incident surface Ai).

[0039] Then, the galvanometer mirror 47 scans the first irradiation area R1 and the second irradiation area R2 in the same direction (in this case, the X-axis direction), thereby performing ablation processing of sample A with the first laser beam L1 and ablation processing of the particles Rt generated by the ablation processing of sample A (particles Rt attached to the surface 7s) with the second laser beam L2. Furthermore, the lens 48 focuses the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction (Z-axis direction) of the first laser beam L1 and the second laser beam L2, the second irradiation area R2 is positioned in front of the first irradiation area R1 in the scanning direction Ds (in this case, the X-axis direction) of the first laser beam L1 and the second laser beam L2.

[0040] Therefore, in this case, as shown in Figure 6, particle Rt is removed from the surface 7s of the cover 7 by ablation processing with the second laser beam L2 prior to the passage of the first laser beam L1. This makes it possible to more effectively remove particle Rt from the area on the surface 7s of the cover 7 through which the first laser beam L1 passes. As a result, it becomes possible to more reliably suppress the deterioration of processing quality and processing efficiency.

[0041] In the example in Figures 4 and 6, the first laser beam L1 is focused on the incident surface Ai, resulting in the formation of a first focal point P1 and a first irradiation region R1 at the same position in the Z-axis direction. Similarly, in the example in Figure 4, the second laser beam L2 is focused on the surface 7s, resulting in the formation of a second focal point P2 and a second irradiation region R2 at the same position in the Z-axis direction.

[0042] However, as shown in Figure 7, the first laser beam L1 may be focused at a first position Z1 on the cover 7 side (or opposite side of the cover 7) of the incident surface Ai, so that the first focal point P1 and the first irradiation region R1 are formed separately in the Z-axis direction, or the second laser beam L2 may be focused at a second position Z2 on the sample A side (or opposite side of the sample A) of the surface 7s, so that the second focal point P2 and the second irradiation region R2 are formed separately in the Z-axis direction. In other words, the first focal point P1 of the first laser beam L1 does not have to coincide with the processing point of sample A, and the second focal point P2 of the second laser beam L2 does not have to coincide with the processing point of cover 7.

[0043] Various configurations are possible for the branching of the laser beam L by the spatial light modulator 45. For example, in the example shown in Figure 4, the spatial light modulator 45 branches the laser beam L into two laser beams (first laser beam L1 and second laser beam L2). The spatial light modulator 45 can generate the first laser beam L1 and the second laser beam L2 by modulating and branching the laser beam L using a modulation pattern that includes a diffraction grating pattern, for example. In this case, for example, the first laser beam L1 may be unmodulated light and the second laser beam L2 may be modulated light.

[0044] In other words, the spatial light modulator 45 can emit a portion of the laser light L as unmodulated first laser light L1, and modulate another portion of the laser light L to emit modulated second laser light L2. In this case, the polarization adjustment unit 44 prior to the spatial light modulator 45 may adjust the polarization direction of the laser light L so that the laser light L includes a polarization component that is modulated by the spatial light modulator 45 and a polarization component that is not modulated by the spatial light modulator 45.

[0045] On the other hand, the spatial light modulator 45 may modulate a portion of the laser light L and emit it as modulated light, the first laser light L1, and also emit another portion of the laser light L without modulating it, as unmodulated light, the second laser light L2. Furthermore, the spatial light modulator 45 may modulate a portion of the laser light L and emit it as modulated light, the first laser light L1, and also modulate another portion of the laser light L and emit it as modulated light, the second laser light L2.

[0046] Thus, the laser processing apparatus 20 may further include a control unit 60, which controls the modulation and demodulation of the laser light L by controlling the polarization adjustment unit 44 and the spatial light modulator 45. 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 44 and the spatial light modulator 45, 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 devices. Furthermore, as will be described later, the control unit 60 may further control the output control unit 42.

[0047] Furthermore, the spatial light modulator 45 may split the laser beam L into three or more laser beams. That is, as an example, as shown in Figure 8, the spatial light modulator 45 can emit a portion of the laser beam L as an unmodulated first laser beam L1, modulate another portion of the laser beam L and emit it as a modulated second laser beam L2, and further modulate yet another portion of the laser beam L and emit it as a modulated third laser beam L3. In other words, the laser optical system 40 (laser irradiation unit) can further irradiate with the third laser beam L3.

[0048] At this time, the lens 48 focuses the third laser beam L3 to form a third focal point P3 of the third laser beam L3 at a third position Z3 on the sample A side of the cover 7, and also forms a third irradiation region R3 of the third laser beam L3 on the incident surface Ai of the sample A. The galvanometer mirror 47 then scans the first irradiation region R1 and the third irradiation region R3 in the same direction (in this case, the X-axis direction) to perform ablation processing of the sample A with the unmodulated first laser beam L1 and the modulated third laser beam L3. Here, the third irradiation region R3 may be positioned in front of (or behind or to the side of) the scanning direction Ds relative to the first irradiation region R1. That is, the first irradiation region R1 and the third irradiation region R3 (and furthermore, the second irradiation region R2) may be arranged along the scanning direction Ds (or a direction intersecting the scanning direction Ds).

[0049] In the illustrated example, the third laser beam L3 is focused on the incident surface Ai, so that the third focal point P3 and the third irradiation area R3 are formed at the same position in the Z-axis direction. However, the third laser beam L3 may be focused on a third position Z3 that is on the cover 7 side (or opposite side of the cover 7) from the incident surface Ai, so that the third focal point P3 and the third irradiation area R3 are formed separately in the Z-axis direction. Furthermore, in the illustrated example, the first position Z1 and the third position Z3 coincide in the Z-axis direction, but they may be different from each other.

[0050] As another example, as shown in Figure 9, the spatial light modulator 45 can modulate a portion of the laser light L and emit it as modulated light, the first laser light L1; modulate another portion of the laser light L and emit it as modulated light, the second laser light L2; and further, emit yet another portion of the laser light L without modulating it as unmodulated light, the fourth laser light L4. In other words, the laser optical system 40 (laser irradiation unit) can further irradiate with the fourth laser light L4.

[0051] At this time, the lens 48 can focus the fourth laser beam L4 to form a fourth focal point P4 of the fourth laser beam L4 at a fourth position Z4 closer to the cover 7 than the first focal point P1, and also form a fourth irradiation region R4 of the fourth laser beam L4 on the surface 7s of the cover 7. The galvanometer mirror 47 can then scan the second irradiation region R2 and the fourth irradiation region R4 in the same direction (here, the X-axis direction) to perform ablation processing of particles Rt with the second laser beam L2 and the fourth laser beam L4. Here, the fourth irradiation region R4 may be positioned in front of (or behind or to the side of) the scanning direction Ds relative to the second irradiation region R2. That is, when viewed from the Z-axis direction, the second irradiation region R2 and the fourth irradiation region R4 (and furthermore, the first irradiation region R1) may be arranged along the scanning direction Ds (or a direction intersecting the scanning direction Ds).

[0052] In the illustrated example, the fourth laser beam L4 is focused on the surface 7s of the cover 7, so that the fourth focal point P4 and the fourth irradiation area R4 are formed at the same position in the Z-axis direction. However, the fourth laser beam L4 may be focused on a fourth position Z4 that is on the side of sample A (or opposite to sample A) from the surface 7s of the cover 7, so that the fourth focal point P4 and the fourth irradiation area R4 are formed separately in the Z-axis direction. Furthermore, in the illustrated example, the second position Z2 and the fourth position Z4 coincide in the Z-axis direction, but they may be different from each other.

[0053] Furthermore, as another example, as shown in Figures 10 and 11, the laser optical system 40 (laser irradiation unit) may irradiate multiple fourth laser beams L4. In this case, the lens 48 focuses each of the multiple fourth laser beams L4 to form a fourth focal point P4 of the multiple fourth laser beams L4 at a fourth position Z4 closer to the cover 7 than the first focal point P1, and also forms a fourth irradiation region R4 of the multiple fourth laser beams L4 on the surface 7s of the cover 7. The galvanometer mirror 47 can then perform ablation processing of particles Rt with the second laser beam L2 and the multiple fourth irradiation regions R4 by scanning the second irradiation region R2 and the multiple fourth irradiation regions R4 in the same direction (in this case, the X-axis direction). In this case, the second irradiation region R2 and the multiple fourth irradiation regions R4 (and furthermore, the first irradiation region R1) may be arranged along the scanning direction Ds when viewed from the Z-axis direction. The fourth laser beam L4 can be generated by the spatial light modulator 45 modulating and branching the laser beam L.

[0054] As described above, when the laser optical system 40 irradiates with a fourth laser beam L4 (whether multiple or one), the lens 48 can focus the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, at least a portion of the region Rp2 where the intensity in the second irradiation region R2 peaks is located outside the region Rp1 where the intensity in the first irradiation region R1 peaks and the region Rp4 where the intensity in the fourth irradiation region R4 peaks.

[0055] In the illustrated example, lens 48 focuses the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the entire region Rp2 where the intensity in the second irradiation region R2 peaks is located outside the region Rp1 where the intensity in the first irradiation region R1 peaks and the region Rp4 where the intensity in the fourth irradiation region R4 peaks. Furthermore, in the illustrated example, the entire second irradiation region R2 is located outside the first irradiation region R1 and the fourth irradiation region R4.

[0056] Although not shown in the diagram, the same applies when the laser optical system 40 irradiates with the third laser beam L3. That is, the lens 48 can focus the first laser beam L1, the second laser beam L2, and the third laser beam L3 such that, when viewed from the Z-axis direction, at least a portion of the region where the intensity peaks in the third irradiation region R3 is located outside the region Rp1 where the intensity peaks in the first irradiation region R1 and the region Rp2 where the intensity peaks in the second irradiation region R2.

[0057] Furthermore, the lens 48 may focus the first laser beam L1, the second laser beam L2, and the third laser beam L3 such that, when viewed from the Z-axis direction, the entire region where the intensity peaks in the third irradiation region R3 is located outside the region Rp1 where the intensity peaks in the first irradiation region R1 and the region Rp2 where the intensity peaks in the second irradiation region R2. Moreover, the entire third irradiation region R3 may be positioned outside the first irradiation region R1 and the second irradiation region R2.

[0058] The relationships between the intensity peak region Rp1 in the first irradiation region R1, the intensity peak region Rp2 in the second irradiation region R2, the intensity peak region in the third irradiation region R3, and the intensity peak region Rp4 in the fourth irradiation region R4 are the same as shown in Figures 14, 15, and 21, except when the irradiation regions overlap, so redundant descriptions are omitted.

[0059] Here, when the laser optical system 40 irradiates the fourth laser beam L4, as shown in Figure 12, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that the second position Z2 is located closer to the cover 7 than the fourth position Z4, and the second focal point P2 and the fourth focal point P4 are aligned in the Z-axis direction. In the illustrated example, the spatial light modulator 45 modulates the laser beam L with a modulation pattern including an axicon lens pattern and branches the laser beam L in the Z-axis direction, thereby forming a plurality of fourth focal points P4 aligned in the Z-axis direction.

[0060] Furthermore, as shown in Figure 13, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the Z-axis direction, the second irradiation area R2 is located behind the first irradiation area R1 in the scanning direction Ds (here, the X-axis direction). In the illustrated example, the lens 48 further focuses the fourth laser beam L4 such that, when viewed from the optical axis direction (Z-axis direction) of the first laser beam L1 and the fourth laser beam L4, the fourth irradiation area R4 is located in front of the first irradiation area R1 in the scanning direction Ds (here, the X-axis direction). That is, the lens 48 can focus the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the second irradiation area R2 and the fourth irradiation area R4 are positioned in front of and behind the first irradiation area R1 in the scanning direction Ds, respectively.

[0061] Furthermore, as shown in Figure 14, when viewed from the Z-axis direction, the lens 48 may be configured such that the fourth irradiation region R4 is positioned before and after the first irradiation region R1 in the scanning direction Ds, and the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 are focused such that the second irradiation region R2 overlaps the first irradiation region R1 along the Z-axis direction. Here, an example is shown in which the entirety of the second irradiation region R2 overlaps the first irradiation region R1 when viewed from the Z-axis direction.

[0062] Furthermore, as shown in Figure 15, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that at least one of the second irradiation area R2 of the second laser beam L2 and the fourth irradiation area R4 of the fourth laser beam L4 is elongated in the Y-axis direction, for example, intersecting the scanning direction Ds (here, the X-axis direction), when viewed from the Z-axis direction. In the illustrated example, all of the second irradiation area R2 and the multiple fourth irradiation areas R4 are elongated elliptical shapes in the Y-axis direction when viewed from the Z-axis direction. Such irradiation areas can be formed, for example, by modulating the laser beam L, or the second laser beam L2 and the fourth laser beam L4, using a modulation pattern including a cylindrical lens pattern in the spatial light modulator 45, and then focusing them with the lens 48.

[0063] In the example shown in Figure 15, when viewed from the Z-axis direction, multiple (two in this case) fourth irradiation regions R4 are arranged both before and after the scanning direction Ds relative to the first irradiation region R1, and the second irradiation region R2 is arranged so as to overlap the first irradiation region R1 in the Z-axis direction.

[0064] Furthermore, as shown in Figure 16, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the Z-axis direction, the second irradiation area R2 is located laterally to the first irradiation area R1 in the scanning direction Ds. In the illustrated example, the galvanometer mirror 47 scans the first irradiation area R1 and the second irradiation area R2 at a specific position in the Y-axis direction (one planned scanning line) with the scanning direction Ds being from one X-axis direction to the other, and then moves them in the feed direction Di from one Y-axis direction to the other, positioning them at another position in the Y-axis direction (another planned scanning line). Subsequently, the first irradiation area R1 and the second irradiation area R2 are scanned at this other position in the Y-axis direction with the scanning direction Ds being from the other X-axis direction to the one.

[0065] In the illustrated example, the lens 48 focuses the first laser beam L1 and the second laser beam L2 such that, when viewed from the Z-axis direction, the second irradiation area R2 is positioned in the Y-axis direction (another planned scanning line) where the first irradiation area R1 is scanned later. Furthermore, when the laser optical system 40 further irradiates with the fourth laser beam L4, the lens 48 focuses the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the fourth irradiation area R4 is positioned in another position in the Y-axis direction (yet another planned scanning line) where the first irradiation area R1 is scanned later. That is, the lens 48 may further focus the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the fourth irradiation area R4 is positioned laterally to the first irradiation area R1 and the second irradiation area R2 in the scanning direction Ds.

[0066] In this case, as shown in Figure 17, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that at least one of the second irradiation region R2 and the fourth irradiation region R4 is elongated in the scanning direction Ds (here, the X-axis direction) when viewed from the Z-axis direction. In the illustrated example, the second irradiation region R2 and all of the multiple fourth irradiation regions R4 are elongated elliptical in the scanning direction Ds when viewed from the Z-axis direction.

[0067] Furthermore, as shown in Figure 18, the lens 48 may focus the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the arrangement of the second irradiation region R2 and / or the fourth irradiation region R4 is combined with the arrangement of the second irradiation region R2 and / or the fourth irradiation region R4 to the side in the scanning direction relative to the first irradiation region R1. In the illustrated example, a helical machining process is performed by sequentially repeating the following: scanning with scanning direction Dsy in the direction from one side of the Y-axis to the other; scanning with scanning direction Dsx in the direction from one side of the X-axis to the other; scanning with scanning direction Dsy in the direction from one side of the Y-axis to the other; and scanning with scanning direction Dsx in the direction from one side of the X-axis to the other.

[0068] In contrast, the lens 48 focuses the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that, when viewed from the Z-axis direction, the second irradiation region R2 and the fourth irradiation region R4 are positioned in the front-to-back direction of the scanning direction Dsy, respectively, relative to the first irradiation region R1, and the fourth irradiation region R4 is positioned on each of the sides of the scanning direction Dsy (i.e., each of the front-to-back directions of the scanning direction Dsx).

[0069] In this case, as shown in Figure 19, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that at least one of the second irradiation region R2 and the fourth irradiation region R4 is elongated in the scanning direction Dsx when viewed from the Z-axis direction. In the illustrated example, the second irradiation region R2 and all of the multiple fourth irradiation regions R4 are elongated elliptical in the scanning direction Dsx when viewed from the Z-axis direction.

[0070] Furthermore, as shown in Figure 20, the lens 48 may focus the first laser beam L1, the second laser beam L2, and the fourth laser beam L4 such that the arrangement of the second irradiation region R2 and the fourth irradiation region R4 in Figure 18 is rotated by an angle of approximately 45° around the first irradiation region R1. In this case, as shown in Figure 21, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that at least one of the second irradiation region R2 and the fourth irradiation region R4 is elongated in the X-axis direction when viewed from the Z-axis direction. In the illustrated example, the second irradiation region R2 and all of the multiple fourth irradiation regions R4 are elongated elliptical in the X-axis direction when viewed from the Z-axis direction.

[0071] As described above, when viewed from the Z-axis direction, the statement that the second irradiation region R2 is located laterally to the first irradiation region R1 in the scanning direction Ds can include the state in which the first irradiation region R1 and the second irradiation region R2 are aligned along a direction perpendicular to the scanning direction Ds (or scanning directions Dsx, Dsy), as shown in Figures 16-19, and the state in which the second irradiation region R2 is shifted with respect to a direction perpendicular to the scanning direction (X-axis direction or Y-axis direction), as shown in Figure 20.

[0072] The above examples illustrate various modes of branching the laser beam L using the spatial light modulator 45 and various modes of focusing the light using the lens 48. However, the branching of the laser beam L using the spatial light modulator 45 and the focusing of the light using the lens 48 are not limited to the modes described above, and further modifications may be made, for example, by arbitrarily combining each mode.

[0073] Next, an example of a laser processing method according to this embodiment will be described. Figure 22 is a flowchart of an example of a laser processing method according to the first embodiment. The laser processing method according to this embodiment is performed using the laser processing apparatus 20 described above. Here, we will illustrate the case in which the laser optical system 40 (laser irradiation unit) irradiates with a first laser beam L1 and a second laser beam L2.

[0074] As shown in Figure 22, in the laser processing method according to this embodiment, the irradiation conditions for the laser beam L are determined (step S101). Specifically, in step S101, the patterns (irradiation conditions) at the processing points (focus points) of the first laser beam L1 and the second laser beam L2 are determined. For example, the irradiation conditions are determined to be conditions such as branching the laser beam L in a direction intersecting the optical axis to generate the second laser beam L2, or conditions such that the beam pattern at the second focus point P2 of the second laser beam L2 is top-hat shaped.

[0075] These irradiation conditions are related to the generation of the modulation pattern to be displayed on the spatial light modulator 45 in a later step. For example, in order to realize irradiation conditions that generate a first laser beam L1 and a second laser beam L2 by splitting the laser beam L in a direction intersecting the optical axis, the modulation pattern should be generated to include a diffraction grating pattern. Therefore, in the next step, the modulation pattern to be displayed on the spatial light modulator 45 is determined (step S102). Step S102 will be explained in more detail.

[0076] Figure 23 is a flowchart showing the specific steps of step S102 shown in Figure 22. As shown in Figure 23, in step 102, the control unit 60 acquires various conditions for generating the modulation pattern to be displayed on the spatial light modulator 45. Specifically, here, the control unit 60 first acquires the set distance (step S201). The set distance is a set value of the distance between the first focal point P1 (first position Z1) and the second focal point P2 (second position Z2) in the optical axis direction (Z axis direction) of the first laser beam L1 and the second laser beam L2. The set distance is determined based on the distance between sample A and cover 7. The distance between sample A and cover 7 may be obtained by using the design value if the design value is known, or by measuring it using an optical method if the design value is unknown. The control unit 60 can acquire the set distance by, for example, receiving input of the set distance determined based on the distance between sample A and cover 7.

[0077] Next, the control unit 60 acquires the focal length of the Fresnel lens pattern included in the modulation pattern displayed on the spatial light modulator 45 (step S202). This is because, when the first laser beam L1 is unmodulated light and the second laser beam L2 is modulated light, the first focal point P1 of the first laser beam L1 is formed on a focal plane that is separated from the lens 48 by the focal length of the lens 48, while the second focal point P2 of the second laser beam L2 is formed at a position closer to the cover 7 than the first focal point P1, on the composite focal plane of the lens 48 and the Fresnel lens pattern.

[0078] Next, the control unit 60 acquires the output value (processing point output) of the first laser beam L1 at the first focusing point P1 (first irradiation area R1) for ablation processing of sample A (step S203). The control unit 60 also acquires the output value (processing point output) of the second laser beam L2 at the second focusing point P2 (second irradiation area R2) for ablation processing of particles Rt on the cover 7 side (step S204). The control unit 60 can acquire these output values, for example, by receiving input of these output values. Note that the processing point output of the second laser beam L2 may be a fixed value if the material of the cover 7 does not change.

[0079] Next, the control unit 60 acquires the grayscale values ​​of the Fresnel lens pattern (phase image) (step S205). The grayscale values ​​of the Fresnel lens pattern are determined such that the ratio of the intensity at the first focal point P1 of the first laser beam L1 to the intensity at the second focal point P2 of the second laser beam L2 is a desired set ratio. The control unit 60 can acquire these grayscale values, for example, by receiving input for the grayscale values.

[0080] Next, the control unit 60 generates a modulation pattern based on the various conditions acquired above (step S206). Specifically, the control unit 60 determines the Fresnel lens pattern based on the focal length of the Fresnel lens pattern acquired in step S202 and the gradation value of the Fresnel lens pattern acquired in step S205. The control unit 60 also determines, for example, the axicon lens pattern and the diffraction grating pattern based on the irradiation conditions determined in step S101.

[0081] In this case, the diffraction grating pattern can be determined based, for example, on the processing point output of the second laser beam L2, the branching direction of the laser beam L, the number of branching points of the laser beam L, the arrangement of the second laser beam L2 generated by the branching, and the branching distance. The branching distance is the distance between the center of the first irradiation area R1 of the first laser beam L1 and the center of the second irradiation area R2 of the second laser beam L2, as viewed from the Z-axis direction.

[0082] Subsequently, the control unit 60 displays the modulation pattern generated in step S206 on the spatial light modulator 45 (step S207). As a result, the laser light L is modulated by the modulation pattern in the spatial light modulator 45, and a first laser beam L1 and a second laser beam L2 are generated from the laser light L. In addition, the first laser beam L1 and the second laser beam L2 are focused by the lens 48, and a first focus point P1 and a second focus point P2 are simultaneously formed.

[0083] As shown in Figure 22, in the subsequent step, the control unit 60 adjusts the output of the laser beam L by controlling, for example, the output control unit 42, which is a variable attenuator (step S103). In step S103, the control unit 60 can control the output control unit 42 so that the output at the first focusing point P1 (first irradiation area R1) of the first laser beam L1 becomes the processing point output acquired in step S203, and the output at the second focusing point P2 (second irradiation area R2) of the second laser beam L2 becomes the processing point output acquired in step S204.

[0084] Then, for example, when the control unit 60 displays a modulation pattern on the spatial light modulator 45, it controls the laser output unit 30 to output laser light L and controls the galvanometer mirror 47 to scan the first laser light L1 and the second laser light L2, thereby performing ablation of sample A and ablation of particles Rt (step S104: focusing step and scanning step).

[0085] Specifically, in step S104, as shown in Figures 4 and 5, the first laser beam L1 is focused to form a first focal point P1 of the first laser beam L1 at a first position Z1 on the sample A side of the cover 7, and a first irradiation area R1 of the first laser beam L1 is formed on the incident surface Ai of the sample A. Furthermore, the second laser beam L2 is focused to form a second focal point P2 of the second laser beam L2 at a second position Z2 on the cover 7 side of the first position Z1, and a second irradiation area R2 of the second laser beam L2 is formed on the surface 7s of the cover 7 (step S301: focusing step).

[0086] Furthermore, in step S104, by scanning the first irradiation area R1 and the second irradiation area R2 in the same direction (in this case, the X-axis direction), ablation processing of sample A with the first laser beam L1 and ablation processing of particles Rt attached to the surface 7s of cover 7 with the second laser beam L2 are performed (step S302: scanning step). At this time, in step S301, the first laser beam L1 and the second laser beam L2 are focused such that, when viewed from the optical axis direction (Z-axis direction) of the first laser beam L1, at least a part of the region Rp2 where the intensity in the second irradiation area R2 is at its peak is located outside the region Rp1 where the intensity in the first irradiation area R1 is at its peak.

[0087] As described above, in the laser processing apparatus 20 and laser processing method according to the first embodiment, when the first laser beam L1 is focused, a first focusing point P1 of the first laser beam L1 is formed at a first position Z1 on the sample A side of the cover 7, and a first irradiation region R1 of the first laser beam L1 is formed on the incident surface Ai of the sample A. When the second laser beam L2 is focused, a second focusing point P2 of the second laser beam L2 is formed at a second position Z2 on the cover 7 side of the first position Z1, and a second irradiation region R2 of the second laser beam L2 is formed on the surface 7s of the cover 7 on the sample A side. Then, when the first irradiation region R1 and the second irradiation region R2 are scanned in the same direction, ablation processing of the sample A by the first laser beam L1 and ablation processing of particles Rt attached to the surface 7s of the cover 7 by the second laser beam L2 are performed.Therefore, it becomes possible to remove particles Rt attached to the cover 7.

[0088] In particular, in the laser processing apparatus 20 and laser processing method according to the first embodiment, at least a portion of the region Rp2 where the intensity in the second irradiation region R2 peaks is located outside the region Rp1 where the intensity in the first irradiation region R1 peaks, when viewed from the optical axis direction of the first laser beam L1. Therefore, it is possible to scan the first irradiation region R1 and the second irradiation region R2 in such a way that the area on the surface 7s of the cover 7 on the sample A side is to be scanned in advance by the second irradiation region R2. Thus, particles Rt adhering to that area can be suitably removed by ablation processing.

[0089] Furthermore, the laser processing apparatus 20 according to the first embodiment further includes a laser output unit 30 for outputting laser light L. The laser optical system 40 further includes a spatial light modulator 45 that receives the incident laser light L output from the laser output unit 30, modulates the laser light L to generate and emit a first laser light L1 and a second laser light L2. Therefore, the first laser light L1 and the second laser light L2 can be easily generated using the spatial light modulator 45.

[0090] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the spatial light modulator 45 may emit a portion of the laser light L as unmodulated first laser light L1, and modulate another portion of the laser light L to emit modulated second laser light L2. Alternatively, the spatial light modulator 45 may modulate a portion of the laser light L to emit modulated first laser light L1, and emit another portion of the laser light L to emit unmodulated second laser light L2.

[0091] As described above, by using the spatial light modulator 45, it is possible to make the first laser beam L1 for ablation of sample A and the second laser beam L2 for ablation of particle Rt modulated or unmodulated.

[0092] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction of the first laser beam L1, the entire region Rp2 where the intensity in the second irradiation region R2 is at its peak is located outside the region Rp1 where the intensity in the first irradiation region R1 is at its peak. In this case, it becomes possible to more reliably scan the area on the surface 7s of the cover 7 that the first laser beam L1 is about to pass through in advance with the second irradiation region R2.

[0093] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the laser optical system 40 may further irradiate the third laser beam L3. In this case, the lens 48 may focus the third laser beam L3 to form a third focal point P3 of the third laser beam L3 at a third position Z3 on the sample A side of the cover 7, and also form a third irradiation region R3 of the third laser beam L3 on the incident surface Ai of the sample A. In addition, the galvanometer mirror 47 may perform ablation processing of the sample A with the first laser beam L1 and the third laser beam L3 by scanning the first irradiation region R1 and the third irradiation region R3 in the same direction. In this case, it becomes possible to perform ablation processing of the sample A more efficiently.

[0094] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the laser optical system 40 may further irradiate with the fourth laser beam L4. In this case, the lens 48 may focus the fourth laser beam L4 to form a fourth focusing point P4 of the fourth laser beam L4 at a fourth position Z4 on the cover 7 side of the first focusing point P1, and also form a fourth irradiation area R4 of the fourth laser beam L4 on the surface 7s of the cover 7. In addition, the galvanometer mirror 47 may perform ablation processing of particles Rt by the second laser beam L2 and the fourth laser beam L4 by scanning the second irradiation area R2 and the fourth irradiation area R4 in the same direction. In this case, it becomes possible to remove particles Rt by ablation processing more efficiently.

[0095] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that, when viewed from the optical axis direction of the second laser beam L2 and the fourth laser beam L4, the region Rp2 where the intensity in the second irradiation region R2 is at its peak does not overlap with the region Rp4 where the intensity in the fourth irradiation region R4 is at its peak. In this case, the area on the surface 7s of the cover 7 on the sample A side that the first laser beam L1 is about to pass through can be scanned multiple times in advance by the second irradiation region R2 and the fourth irradiation region R4. Therefore, by making the fluence of the second laser beam L2 and the fourth laser beam L4 lower, it becomes possible to remove particles Rt while suppressing damage to the cover 7.

[0096] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the second laser beam L2 and the fourth laser beam L4 such that the second position Z2 is located closer to the cover 7 than the fourth position Z4, and the second focusing point P2 and the fourth focusing point P4 are aligned in the optical axis direction of the second laser beam L2. By aligning the focusing points of multiple lasers (second focusing point P2 and fourth focusing point P4) in the optical axis direction of the second laser beam L2 in this way, it becomes possible to effectively remove particles Rt by ablation processing even if the position of the cover 7 or the focusing points fluctuates along the optical axis direction.

[0097] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction of the first laser beam L1 and the second laser beam L2, the second irradiation area R2 is located in front of the first irradiation area R1 in the scanning direction. In this case, the area on the surface 7s of the cover 7 on the sample A side that the first laser beam L1 is about to pass through can be more reliably pre-scanned by the second irradiation area R2 of the second laser beam L2, which is located in front of the scanning direction of the first laser beam L1.

[0098] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction of the first laser beam L1 and the second laser beam L2, the second irradiation area R2 is located behind the first irradiation area R1 in the scanning direction. In this case, by scanning the area on the surface 7s of the cover 7 on the sample A side with the second irradiation area R2 located behind the scanning direction of the first laser beam L1, it is possible to ensure that the area is already free of particles Rt when the first laser beam L1 is about to pass over it next.

[0099] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction of the first laser beam L1 and the second laser beam L2, the second irradiation area R2 is located laterally to the first irradiation area R1 in the scanning direction. In this case, by scanning the area to the side of the area through which the first laser beam L1 passes on the surface 7s of the cover 7 on the sample A side with the second irradiation area R2, it is possible to ensure that the particles Rt have already been removed from that area when the first laser beam L1 is about to pass through it later.

[0100] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the second irradiation area R2 may be elliptical in shape when viewed from the optical axis direction of the second laser beam L2. In this case, it becomes possible to remove particles Rt over a wider area.

[0101] Furthermore, in the laser processing apparatus 20 according to the first embodiment, the lens 48 may include an fθ lens. In this way, the first laser beam L1 and the second laser beam L2, etc., may be focused using an fθ lens.

[0102] Furthermore, the microscope device 1 according to the first embodiment includes a laser processing apparatus 20 according to this embodiment and a microscope unit 4 for observing the processed cross-section formed on the sample A by ablation processing with the first laser beam L1. Since the microscope device 1 is equipped with the above-mentioned laser processing apparatus 20, it is possible to remove particles Rt from the surface 7s of the cover 7 and to observe the processed cross-section of the sample A. [Second Embodiment]

[0103] Next, a laser processing apparatus and laser processing method according to the second embodiment will be described. As shown in Figure 24, the laser processing apparatus 20 according to the second embodiment differs from the laser processing apparatus 20 according to the first embodiment mainly in that the incident surface Ai of the sample A is inclined with respect to the optical axis Ox of the first laser beam L1. This point will be explained in more detail.

[0104] In other words, the lens 48 focuses the first laser beam L1 to form a first focal point P1 of the first laser beam L1 at a first position Z1 on the sample A side of the cover 7, and forms a passage region R5 through which the first laser beam L1 passes on the sample A side surface 7s of the cover 7, while simultaneously forming a first irradiation region R1 of the first laser beam L1 on the incident surface Ai of the sample A. Furthermore, the lens 48 focuses the second laser beam L2 to form a second focal point P2 of the second laser beam L2 at a second position Z2 on the cover 7 side of the first position Z1, and simultaneously forms a second irradiation region R2 of the second laser beam L2 on the sample A side surface 7s of the cover 7.

[0105] Furthermore, the incident surface Ai of sample A is tilted with respect to the optical axis Ox (here, an axis parallel to the Z-axis) of the first laser beam L1 such that the normal N of the incident surface Ai in the first irradiation region R1 reaches outside the passing region R5. In addition, here, the incident surface Ai is tilted with respect to the optical axis Ox of the first laser beam L1 such that the normal N reaches outside the cover 7. Moreover, here, the sample holder 2 includes a placement surface 2s in which sample A is positioned such that the incident surface Ai is tilted with respect to the optical axis Ox of the first laser beam L1. That is, here, the tilt of the incident surface Ai with respect to the optical axis Ox is obtained by the tilt of the placement surface 2s.

[0106] However, in the laser processing apparatus 20 according to the second embodiment, the laser optical system 40 (laser irradiation unit) further includes an optical axis adjustment unit 81 that tilts the optical axis Ox of the first laser beam L1 with respect to the normal N of the incident surface Ai, and at least a portion of the tilt of the incident surface Ai with respect to the optical axis Ox may be obtained by the optical axis adjustment unit 81. In addition, in the laser processing apparatus 20 according to this embodiment, the sample holder 2 may further include an angle adjustment unit 82 that adjusts the angle of the placement surface 2s.

[0107] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the inner surface 6s of the sample chamber 6 may be provided with a collection area 70 made of a material to which particles Rt are more likely to adhere than the inner surface 6s, in the portion where the normal N in the sample chamber 6 reaches. In this case, the inner surface 6s is a flat surface of a metal such as stainless steel, and the collection area 70 may have a porous structure made of the same material as the sample A, for example, so that particles Rt bind together and are difficult to remove.

[0108] In the laser processing apparatus 20 according to the second embodiment, the lens 48 does not have to be configured to focus the first laser beam L1 and the second laser beam L2 such that, when viewed from the optical axis direction of the first laser beam L1, at least a portion of the region Rp2 where the intensity in the second irradiation region R2 is at its peak is located outside the region Rp1 where the intensity in the first irradiation region R1 is at its peak.

[0109] Furthermore, as shown in Figure 25, in the laser processing apparatus 20 according to the second embodiment, recesses 6c for collecting particles Rt may be formed on the inner surface 6s of the sample chamber 6 at all points along the normal N in the sample chamber 6. In the illustrated example, the distance T1 from the sample A to the bottom surface 6b of the recess 6c is greater than the distance T2 from the sample A to the cover 7, with respect to the optical axis of the first laser beam L1. In addition, the above-mentioned collection area 70 may be further provided on the inner surface (e.g., bottom surface 6b) of the recess 6c.

[0110] The laser processing method performed using the laser processing apparatus 20 according to the second embodiment described above includes a step S401 (focusing step) for focusing the first laser beam L1 to form a first focusing point P1 of the first laser beam L1 at a first position Z1 on the sample A side of the cover 7, and for forming a passage region R5 through which the first laser beam L1 passes on the surface 7s of the cover 7 on the sample A side, while forming a first irradiation region R1 of the first laser beam L1 on the incident surface Ai of the sample A, and for focusing the second laser beam L2 to form a second focusing point P2 of the second laser beam L2 at a second position Z2 on the cover 7 side of the first position Z1, and for forming a second irradiation region R2 of the second laser beam L2 on the surface 7s of the cover 7 on the sample A side. Furthermore, the laser processing method according to this embodiment includes a step S402 (scanning step) for performing ablation processing of sample A with the first laser beam L1 and ablation processing of particles Rt (particles Rt attached to the surface 7s) generated by the ablation processing of sample A with the second laser beam L2, by scanning the first irradiation area R1 and the second irradiation area R2. The incident surface Ai is inclined with respect to the optical axis Ox of the first laser beam L1 such that the normal N of the incident surface Ai in the first irradiation area R1 reaches outside the passing area R5.

[0111] As described above, in the laser processing apparatus 20 and laser processing method according to the second embodiment, when the first laser beam L1 is focused, a first focusing point P1 of the first laser beam L1 is formed at a first position Z1 on the sample A side of the cover 7, and a passage region R5 through which the first laser beam L1 passes is formed on the sample A side surface 7s of the cover 7, while a first irradiation region R1 of the first laser beam L1 is formed on the incident surface Ai of the sample A. When the second laser beam L2 is focused, a second focusing point P2 of the second laser beam L2 is formed at a second position Z2 on the cover 7 side of the first position Z1, and a second irradiation region R2 of the second laser beam L2 is formed on the sample A side surface 7s of the cover 7. Then, by scanning the first irradiation region R1 and the second irradiation region R2, ablation processing of the sample A with the first laser beam L1 and ablation processing of particles Rt attached to the cover 7 with the second laser beam L2 are performed. Therefore, the particles Rt attached to the cover 7 can be removed. Thus, the decrease in the transmittance of the cover 7 is suppressed.

[0112] In particular, in the laser processing apparatus 20 and laser processing method according to the second embodiment, the incident surface Ai of the first laser beam L1 on sample A is tilted with respect to the optical axis Ox of the first laser beam L1 such that the normal N of the incident surface Ai in the first irradiation region R1 reaches outside the passing region R5. As shown in Figures 24 and 25, when the first laser beam L1 is irradiated onto sample A, more particles Rt are scattered in the direction normal to the incident surface Ai of the first laser beam L1 on sample A than in other directions. Therefore, the amount of particles Rt adhering to the passing region R5 through which the first laser beam L1 passes on the surface 7s of the cover 7 is reduced, and the decrease in transmittance is more reliably suppressed.

[0113] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the sample holder 2 may include a placement surface 2s on which the sample A is positioned such that the incident surface Ai is inclined with respect to the optical axis Ox of the first laser beam L1. In this way, when inclining the incident surface Ai with respect to the optical axis Ox of the first laser beam L1 such that the normal N of the incident surface Ai reaches outside the passing region R5, the elements on the sample holder 2 side on which the sample A is positioned (placement surface 2s) may contribute.

[0114] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the sample holder 2 may further include an angle adjustment unit 82 for adjusting the angle of the placement surface 2s. In this case, the angle of the placement surface 2s becomes adjustable.

[0115] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the laser optical system 40 (laser irradiation unit) may further include an optical axis adjustment unit 81 that tilts the optical axis Ox of the first laser beam L1 with respect to the normal N of the incident surface Ai. In this way, when tilting the incident surface Ai with respect to the optical axis Ox of the first laser beam L1 so that the normal N of the incident surface Ai reaches outside the passing region R5, elements on the laser optical system 40 side (optical axis adjustment unit 81) may contribute.

[0116] Furthermore, the laser processing apparatus 20 according to the second embodiment further includes a sample chamber 6 for housing the sample holder 2, and recesses 6c for collecting particles Rt may be formed on the inner surface 6s of the sample chamber 6 at all points along the normal N in the sample chamber 6. In this case, by collecting particles Rt in the recesses 6c of the sample chamber 6, the amount of particles Rt adhering to the surface 7s of the cover 7 can be reduced, and the reduction in the transmittance of the transparent member can be suppressed more reliably.

[0117] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the distance T1 from the sample A to the bottom surface 6b of the recess 6c in the optical axis direction of the first laser beam L1 may be greater than the distance T2 from the sample A to the cover 7. In this case, the adhesion of particles Rt reflected from the bottom surface 6b of the recess 6c to the cover 7 is reduced.

[0118] Furthermore, the laser processing apparatus 20 according to the second embodiment further comprises a sample chamber 6 for housing the sample holder 2, and a collection area 70 made of a material to which particles Rt are more likely to adhere than the inner surface 6s is provided on the inner surface 6s of the sample chamber 6 in the portion where the normal N in the sample chamber 6 reaches. In this case, by collecting particles Rt in the collection area 70 of the sample chamber 6, the amount of particles Rt adhering to the surface 7s of the cover 7 can be reduced, and the reduction in the transmittance of the cover 7 can be suppressed more reliably.

[0119] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the incident surface Ai may be inclined with respect to the optical axis Ox of the first laser beam L1 such that the normal N reaches the outside of the cover 7. In this case, the particles Rt adhering to the surface 7s of the cover 7 can be reduced more reliably.

[0120] Here, the microscope device 1 may include the laser processing apparatus 20 according to the second embodiment described above, and a microscope unit 4 for observing the processed cross-section formed on the sample A by ablation processing with the first laser beam L1. With this microscope device 1, since it includes the laser processing apparatus 20 described above, it is possible to suppress the reduction in the transmittance of the cover 7 and to observe the processed cross-section of the sample A.

[0121] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments and can be modified as needed.

[0122] For example, as shown in Figure 26, the microscope apparatus 1 according to the first and second embodiments may not have a sample chamber 6. In this case, elements corresponding to the recess 6c and collection area 70 may be provided on the inner surface 10s of the chamber 10.

[0123] Furthermore, in the laser processing apparatus 20 according to the second embodiment, the incident surface Ai may be inclined with respect to the optical axis Ox of the first laser beam L1 such that the normal N extends outside the range in which a passing region R5 can be formed by scanning the first irradiation region R1 on the surface 7s of the cover 7.

[0124] Furthermore, the elements according to the first embodiment and the elements according to the second embodiment can be combined in any way. For example, in the laser processing apparatus 20 according to the first embodiment, as in the second embodiment, the incident surface Ai of the first laser beam L1 in the sample A may be tilted with respect to the optical axis Ox of the first laser beam L1 such that the normal N of the incident surface Ai in the first irradiation region R1 reaches outside the passing region R5. [Explanation of Symbols]

[0125] 1...Microscope device, 2...Sample holder (placement part), 2s...Placement surface, 4...Microscope part, 7...Cover (transmitting member), 7s...Surface, 40...Laser optical system (laser irradiation part), 47...Galvanometer mirror (scanning part), 48...Lens (light focusing part), 81...Optical axis adjustment part, 82...Angle adjustment part, A...Sample (object), Ai...Incident surface, L...Laser light, L1...First laser light, L2...Second laser light, R1...First irradiation area, R2...Second irradiation area, Rt...Particle.

Claims

1. The arrangement section where the object is placed, A laser irradiation unit for irradiating with a first laser beam and a second laser beam, Between the object placed in the arrangement section and the laser irradiation section, a transparent member is positioned on the optical axis of the first laser beam and the second laser beam, and transmits the first laser beam and the second laser beam. Equipped with, The laser irradiation unit is A focusing unit for focusing the first laser beam to form a first focusing point of the first laser beam at a first position closer to the object than the transparent member, and for forming a passing region on the object-side surface of the transparent member through which the first laser beam passes, while forming a first irradiation region of the first laser beam on the incident surface of the object, and for focusing the second laser beam to form a second focusing point of the second laser beam at a second position closer to the transparent member than the first position, and for forming a second irradiation region of the second laser beam on the object-side surface of the transparent member, A scanning unit for performing ablation processing of the target object with the first laser beam and ablation processing of particles generated by the ablation processing of the target object with the second laser beam by scanning the first irradiation area and the second irradiation area, The incident surface is inclined with respect to the optical axis of the first laser beam such that the normal to the incident surface in the first irradiation region reaches outside the passing region. Laser processing equipment.

2. The arrangement portion includes an arrangement surface on which the object is arranged such that the incident surface is inclined with respect to the optical axis of the first laser beam. The laser processing apparatus according to claim 1.

3. The arrangement unit further includes an angle adjustment unit for adjusting the angle of the arrangement surface. The laser processing apparatus according to claim 2.

4. The laser irradiation unit further includes an optical axis adjustment unit that tilts the optical axis of the first laser beam with respect to the normal of the incident surface. The laser processing apparatus according to claim 1.

5. The facility further comprises a housing section for housing the aforementioned arrangement section, On the inner surface of the containment section, recesses are formed in the portion of the normal to the containment section for collecting the particles. The laser processing apparatus according to claim 1.

6. With respect to the optical axis direction of the first laser beam, the distance from the object to the bottom surface of the recess is greater than the distance from the object to the transparent member. The laser processing apparatus according to claim 5.

7. The facility further comprises a housing section for housing the aforementioned arrangement section, On the inner surface of the containment section, a collection area is provided, in the portion of the containment section where the normal to the containment section reaches, made of a material to which particles are more likely to adhere than the inner surface. The laser processing apparatus according to claim 1.

8. The incident surface is inclined with respect to the optical axis of the first laser beam such that the normal vector extends outside the range in which the passage region can be formed by scanning the first irradiation region on the surface. The laser processing apparatus according to claim 1.

9. The incident surface is inclined with respect to the optical axis of the first laser beam such that the normal vector reaches the outside of the transmitting member. The laser processing apparatus according to claim 1.

10. A laser processing apparatus according to any one of claims 1 to 9, A microscope unit for observing the processed cross-section formed on the object by ablation processing using the first laser beam, A microscope device equipped with the following features.

11. A laser processing method using a laser processing apparatus having a placement section on which an object is placed, a laser irradiation section for irradiating a first laser beam and a second laser beam, and a transparent member positioned between the object placed in the placement section and the laser irradiation section, on the optical axes of the first laser beam and the second laser beam, and transmitting the first laser beam and the second laser beam, wherein A focusing step for the first laser beam to be focused to form a first focusing point of the first laser beam at a first position closer to the object than the transparent member, and to form a passing region through which the first laser beam passes on the object-side surface of the transparent member, while forming a first irradiation region of the first laser beam on the incident surface of the object, and for the second laser beam to be focused to form a second focusing point of the second laser beam at a second position closer to the transparent member than the first position, and to form a second irradiation region of the second laser beam on the object-side surface of the transparent member, A scanning step for performing ablation processing of the target object with the first laser beam and ablation processing of particles generated by the ablation processing of the target object with the second laser beam, by scanning the first irradiation area and the second irradiation area. Equipped with, The incident surface is inclined with respect to the optical axis of the first laser beam such that the normal to the incident surface in the first irradiation region reaches outside the passing region. Laser processing method.

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