Ablation method and ablation unit

Abstract

An ablation method according to one aspect of the present disclosure includes a step of displaying, on a monitor, an image of a camera that is imaging an object to be ablated, a step of designating a region of the object to be irradiated with laser light by tracing the image displayed on the monitor, and a step of irradiating the designated region with laser light to ablate it.

Description

Technical Field

[0001] The present disclosure relates to an ablation method and an ablation unit.

Background Art

[0002] There is known an analysis unit that irradiates a target object with laser light and analyzes the contained elements of the target object. As such an analysis unit, there is known an analysis unit including an ablation unit including laser light emitted from a laser light source and an optical system that reflects the laser light toward the target object, and an analyzer that performs analysis by an inductively coupled plasma method (International Publication No. 2019 / 202689).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the analysis unit described in Patent Document 1, since the ablation unit can reflect the laser light with two mirrors and move the irradiation position two-dimensionally, it is said that the analyzable position of the target object can be widened. On the other hand, it is also required to irradiate and analyze a partial or local region of the target object, rather than the entire target object. Such a partial or local region may have a non-geometrical shape.

[0005] In view of the above circumstances, an object of the present disclosure is to provide an ablation method capable of easily determining, with a high degree of freedom, a region irradiated with laser light of a target object.

Means for Solving the Problems

[0006] An ablation method according to an aspect of the present disclosure made to solve the above problems includes a step of displaying an image of a camera that images an object to be imaged on a monitor, a step of designating a region of the object to be irradiated with laser light by tracing the image displayed on the monitor, and a step of irradiating the designated region with laser light to ablate it.

Effect of the Invention

[0007] An ablation method according to an aspect of the present disclosure can determine the region to be irradiated with laser light of the object to be ablated with a high degree of freedom and easily.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] [Description of Embodiment of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) An ablation method according to an aspect of the present disclosure includes a step of displaying an image of a camera that images an object to be imaged on a monitor, a step of designating a region of the object to be irradiated with laser light by tracing the image displayed on the monitor, and a step of irradiating the designated region with laser light to ablate it.

[0011] Since the ablation method can specify the area to be irradiated with the laser light by tracing the image of the object to be ablated displayed on the monitor, this area can be easily determined with a high degree of freedom even if it has a geometric or non-geometric shape. Therefore, ablation of a desired area of the object to be ablated can be efficiently performed.

[0012] (2) In the above (1), a plurality of areas may be specified in the above specifying step. Since the ablation method can determine the above area with a high degree of freedom, even the specification of a plurality of areas can be easily determined.

[0013] (3) An ablation unit according to another aspect of the present disclosure is a unit that irradiates the surface of an object to be ablated with a laser beam and ablates it, and includes a laser emission unit that emits a laser beam, a light reflection unit that reflects the laser beam to an arbitrary position, a camera that images the object to be ablated, and an image processing unit that includes a monitor that displays an image of this camera, and a light reflection control unit that controls the light reflection unit so that the laser beam is irradiated to a region specified by tracing the image displayed on the monitor.

[0014] Since the ablation unit includes a light reflection unit that reflects the laser beam to an arbitrary position and a light reflection control unit that controls the light reflection unit so that the laser beam is irradiated to a region specified by tracing the image displayed on the monitor, the region to be irradiated with the laser beam can be easily determined with a high degree of freedom, and the laser beam can be efficiently irradiated to this region.

[0015] (4) In the above (3), the ablation unit may further include an objective lens that condenses the laser beam on the surface of the object to be ablated, and the camera and the objective lens may be arranged on the axis of the laser beam incident on the object to be ablated. By arranging the camera and the objective lens on the axis of the laser beam incident on the object to be ablated, the object to be ablated can be easily imaged, and the accuracy of specifying the irradiation region can be improved.

[0016] (5) In the above (3) or (4), the ablation unit may further include an fθ lens that focuses the laser light on the surface of the object to be treated, and a camera for the fθ lens that captures an image for designating the area irradiated by the laser light passing through the fθ lens. By the ablation unit further including an fθ lens, a relatively wide area of the object to be treated can be easily ablated. By the ablation unit including a camera for the fθ lens, the accuracy of designating the irradiation area can be improved.

[0017] (6) In any one of (3) to (5) above, the laser emission unit may have a femtosecond pulse laser oscillator capable of setting the repetition frequency to 1 kHz or more. By irradiating the object to be treated with femtosecond pulse laser light having a repetition frequency of 1 kHz or more, ablation can be performed efficiently.

[0018] (7) In (6) above, the light reflection unit may include a galvanometer mirror, and this galvanometer mirror may change the reflection angle corresponding to the repetition frequency. By the light reflection unit including a galvanometer mirror capable of changing the reflection angle corresponding to the repetition frequency, ablation can be performed more efficiently.

[0019] (8) In any one of (3) to (7) above, the wavelength of the laser light may be deep ultraviolet. By setting the wavelength of the laser light to deep ultraviolet, ablation can be performed more efficiently.

[0020] Note that the area includes a point (resulting from ablation at one point), a line (a continuous straight line, curve, or a combination thereof resulting from multiple ablations).

[0021] [Details of the Embodiment for Carrying Out the Invention] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the drawings are diagrams exemplarily showing the embodiments, and the shape, size, scale, arrangement, etc. of each component (member) may be different from the actual ones.

[0022] <Ablation method> The ablation method includes a step of displaying an image of a camera that is imaging an object to be ablated on a monitor, a step of designating a region of the object to be ablated that is irradiated with laser light by tracing the image displayed on the monitor, and a step of irradiating the designated region with laser light to ablate it. The object to be ablated is not particularly limited and may be a solid object or a liquid object, but the ablation method is particularly suitable for solid objects.

[0023] The ablation method can be performed, for example, using the ablation unit 100 shown in FIGS. 1, 2, and 3. The ablation unit 100 is connected to, for example, an analysis unit 200 that performs elemental analysis, and analyzes the contained elements of the object to be ablated (not shown).

[0024] 〔Analysis unit〕 The analysis unit 200 is not particularly limited and may be, for example, a device that performs a known analysis method such as inductively coupled plasma mass spectrometry or high-frequency inductively coupled plasma optical emission spectrometry.

[0025] 〔Ablation unit〕 The ablation unit 100 includes a laser emission unit 110 that emits laser light L (shown as a dashed line in each figure), a light reflection unit that reflects the laser light L to an arbitrary position, cameras 191, 192, 193 that image the object to be ablated (not shown), and an image processing unit 190 that includes a monitor 195 that displays the images of these cameras 191, 192, 193, and a light reflection control unit 196 that controls the light reflection unit so that the laser light L is irradiated to the designated region by tracing the image displayed on the monitor 195.

[0026] (Cell) The object to be measured is housed in the cell 170 and irradiated with the laser beam L. The cell 170 is a container that houses one or more objects to be measured and prevents the aerosol generated by ablation from scattering. A transparent plate (not shown) through which the laser beam L is incident is disposed on the top surface of the cell 170. That is, the cell 170 has a light incident portion formed of a transparent plate on the incident surface of the laser beam L.

[0027] The cell 170 has a gas supply port 171 to which a carrier gas for transporting the aerosol to the analysis unit 200 is supplied, and a gas discharge port 172 for discharging the carrier gas containing the aerosol. A gas supply pipe P1 is connected to the gas supply port 171, and a gas discharge pipe P2 is connected to the gas discharge port 172.

[0028] By irradiating the surface of the object to be measured housed in the cell 170 with the laser beam L to ablate it, the object to be measured is partially aerosolized. Specifically, when the laser beam L is irradiated, the surface of the object to be measured is vaporized and a part of it is ionized. Further, the laser beam L enters the interior of the object to be measured at a depth of several nm to several μm from the surface, and releases most of its energy to vaporize and fragment the constituent components of the object to be measured. By this ablation, the ionized and vaporized elements, solid particles in which some of these are recondensed, and fragmented fragments are released from the object to be measured as an aerosol. The aerosol is transported to the analysis unit 200 via the gas discharge pipe P2 by a carrier gas such as helium supplied into the cell 170, and the chemical composition of the object to be measured is analyzed.

[0029] (Stage) The cell 170 is disposed on the stage 180. Specifically, the cell 170 housing the object to be measured is disposed on the mounting surface (top surface) of the stage 180 so as not to move relative to the stage 180.

[0030] As a means for preventing the cell 170 from moving relative to the stage 180, it is not particularly limited and may be fixed with bolts, pins, etc., but it is preferably fixed by magnetic force. Specifically, it is preferable to dispose a magnet (not shown) on the stage 180 and fix the cell 170 formed of a magnetic material such as metal by the magnetic force of the magnet. What is disposed on the stage 180 may be a coil (not shown) that generates a magnetic force when energized. The magnet or the coil may be disposed on the cell 170, or may be disposed on both the stage 180 and the cell 170. It is preferable that a guide portion (not shown) for determining the position where the cell 170 is disposed is provided on the placement surface of the stage 180.

[0031] The stage 180 is preferably capable of moving the cell 170 in the axial direction (Z direction) of the laser beam L incident on the object to be measured, and in two directions (X direction and Y direction) that are orthogonal to this axial direction and orthogonal to each other. That is, it is preferable that the placement surface of the stage 180 can move in the X - Y - Z directions. By doing so, the irradiation positions of the laser beam L in the X direction, Y direction, and Z direction on the object to be measured can be easily adjusted.

[0032] As the means for moving the stage 180 in the Z direction (height adjustment means) on the placement surface, it is not particularly limited, but it is preferably configured to be adjustable by driving a piezo element. The upper limit value of the minimum movement unit (resolution) in the movement in the Z direction is preferably 5 nm, more preferably 2 nm, and even more preferably 1 nm. The lower limit value of the minimum movement unit is not particularly limited and may be, for example, 0.1 nm. By setting the minimum movement unit within the above range, the position of the laser beam L focused in the Z direction can be efficiently determined. That is, the focal points of the fθ lens 130 and the objective lens 140, the depth at which the laser beam L enters the object to be measured, etc. can be adjusted with high precision, and as a result, efficient aerosolization and improvement of the analysis accuracy by the analysis unit 200 can be achieved. The stage 180 may be a goniostage capable of changing the angle of the X - Y plane.

[0033] (Laser emission unit) The laser emission unit 110 emits a laser beam L that irradiates the surface of the object to be processed (hereinafter also referred to as the target surface). The laser emission unit 110 includes a known laser oscillator (not shown) such as a solid-state laser, a semiconductor laser, or a gas laser. It is preferable that the wavelength range of the laser beam L can be arbitrarily set. The wavelength of the laser beam L is preferably deep ultraviolet. That is, it is preferable that the laser emission unit 110 can set the wavelength range of the laser beam L to deep ultraviolet. Specifically, it is preferable that the wavelength of the laser beam L can be set to 280 nm or less, more preferably 270 nm or less, and even more preferably 260 nm or less. The lower limit value of the above-mentioned wavelength that can be set is not particularly limited, and may be, for example, 100 nm. By irradiating the target surface with the laser beam L having a deep ultraviolet wavelength, the refinement of aerosol (fragmented pieces) by ablation can be promoted.

[0034] The laser beam L emitted from the laser emission unit 110 may be a continuous wave, but is preferably a pulsed wave. It is preferable that the pulse width of the pulsed wave in the laser beam L emitted from the laser emission unit 110 can be arbitrarily set. The above-mentioned pulse width is preferably settable to 600 femtoseconds or less, and more preferably 300 femtoseconds or less. By irradiating the target surface with the laser beam L having such a pulse width, the refinement of aerosol by ablation can be further promoted.

[0035] By setting the wavelength and pulse width of the laser beam L within the above ranges, the absorption efficiency of the energy of the laser beam L (laser energy) on the target surface is improved, and when the object to be processed is a solid object, the depth at which the laser beam L penetrates the surface (surface layer) of the object to be processed is reduced. That is, the above laser energy can be absorbed in a small volume.

[0036] When the object is a solid and the solid is analyzed (for example, the elements contained are analyzed), when the solid is irradiated with the laser beam L at a deep ultraviolet wavelength and a short pulse of 600 femtoseconds or less, the absorption efficiency of the laser energy on the surface of the solid is improved, and the depth of the ablation mark can be made shallower. Specifically, the depth of the ablation mark can be controlled in nanometer units. By making the depth of the ablation mark shallower, the analysis in the depth direction of the solid can be performed with high accuracy. That is, a dense depth profile of the solid can be obtained. Note that the ablation mark (also referred to as a spot, crater, etc.) means a groove (hole) formed in the solid by ablation with a laser beam.

[0037] In addition, since the laser energy is efficiently absorbed on the surface of the solid, the fragmentation of the fragments broken on the surface is promoted and the aerosolization is improved, and thus the analysis accuracy by the analysis unit 200 can be improved. Specifically, the average particle size of the fragments broken on the surface can be made 400 nm or less, or 300 nm or less, 200 nm or less. Therefore, the ionization of the fragments by the plasma in the analysis unit 200 can be promoted, and the analysis accuracy can be improved. Note that the average particle size means the particle size at the integrated value 50% in the particle size distribution obtained by the laser diffraction scattering method.

[0038] The repetition frequency of the pulse wave of the laser beam L is preferably arbitrarily settable. The repetition frequency is preferably settable to 1 kHz or more, more preferably settable to 10 kHz or more, and even more preferably settable to 100 kHz or more. By setting such a repetition frequency, ablation of the specified irradiation region can be performed at high speed.

[0039] (Lens) The ablation unit 100 has a lens for adjusting the condensing diameter of the laser beam L on the target surface. The ablation unit 100 of the present embodiment includes an fθ lens 130 and an objective lens 140 so that the condensing diameter of the laser beam L can be arbitrarily selected. In the laser ablation unit 100 of the present embodiment, the fθ lens 130 and the objective lens 140 are arranged in parallel in the X direction. The fθ lens 130 condenses the laser beam L on the surface of the object to be processed with a relatively large condensing diameter, and the objective lens 140 condenses the laser beam L with a condensing diameter smaller than that of the fθ lens 130. A beam expander lens (not shown) for expanding the beam diameter may be arranged upstream of the fθ lens 130 and the objective lens 140.

[0040] The objective lens 140 of the present embodiment includes three objective lenses 141, 142, and 143. The three objective lenses 141, 142, and 143 are held by a lens holder 144 in parallel in the X direction. The lens holder 144 is mounted on an objective lens moving means (not shown) such as a known uniaxial stage and can move in the X direction. By moving the lens holder 144, the ablation unit 100 can arbitrarily select the three objective lenses 141, 142, and 143 to vary the condensing diameter of the laser beam L on the target surface.

[0041] It is preferable that the condensing diameter of the laser beam L by at least one objective lens 140 is 2 μm or less. That is, it is preferable that any one of the three objective lenses 141, 142, and 143 has a magnification that can make the condensing diameter of the laser beam L on the target surface 2 μm or less. As the upper limit value of the condensing diameter by the above magnification, 1.5 μm is more preferable, 1.0 μm is further preferable, and 0.5 μm is particularly preferable. By irradiating the target surface with the laser beam L having such a condensing diameter, dense ablation can be performed. The lower limit value of the condensing diameter by the above magnification is not particularly limited and may be, for example, 0.1 μm.

[0042] Specifically, for example, in the case of the first objective lens 141, the lens magnification is preferably selected such that the above-mentioned light condensing diameter is 0.5 μm, in the second objective lens 142, the light condensing diameter is 3.0 μm, and in the third objective lens 143, the light condensing diameter is 5.0 μm. As the lens magnification of each of the three objective lenses 141, 142, and 143, for example, it may be 60 times, 40 times, 20 times, or it may be 50 times, 20 times, 10 times, etc. The light condensing diameter by the fθ lens 130 may be, for example, 10 μm. In this way, since the light condensing diameter on the target surface can be arbitrarily selected by a plurality of lenses, ablation can be performed according to the purpose of analysis, the characteristics of the object to be analyzed, etc.

[0043] (Light reflection part) The light reflection part reflects the laser beam L so that the laser beam L irradiates an arbitrary position on the target surface. That is, the above-mentioned light reflection part controls the irradiation position of the laser beam L on the target surface. The above-mentioned light reflection part is not particularly limited, but it is preferably the galvanometer parts 121 and 122 including a galvanometer mirror. The ablation unit 100 of the present embodiment has a first galvanometer part 121 that controls the irradiation position of the laser beam L transmitted through the objective lens 140, and a second galvanometer part 122 that controls the irradiation position of the laser beam L transmitted through the fθ lens 130. By using such galvanometer parts 121 and 122, the laser beam L transmitted through the fθ lens 130 and the objective lens 140 can move to an arbitrary position on the target surface, and ablation of a desired region on the target surface can be easily performed.

[0044] The first galvanometer unit 121 includes a first galvanometer mirror 121a and a second galvanometer mirror 121b. Each of the two galvanometer mirrors 121a and 121b is provided with a driving unit (not shown) that changes the reflection angle by being rotationally driven. That is, the first galvanometer unit 121 has two driving units. Each of these two driving units is electrically connected to the light reflection control unit 196. The first galvanometer mirror 121a reflects the laser beam L emitted by the laser emission unit 110 and moves the irradiation position in one direction (X direction). The second galvanometer mirror 121b reflects the laser beam L reflected by the first galvanometer mirror 121a and moves the irradiation position in a direction (Y direction) orthogonal to the one direction.

[0045] Similar to the first galvanometer unit 121, the second galvanometer unit 122 includes a third galvanometer mirror 122a that moves the irradiation position of the laser beam L transmitted through the fθ lens 130 in the X direction, and a fourth galvanometer mirror 122b that moves the irradiation position of the laser beam L reflected by the third mirror 122a in the Y direction. The second galvanometer unit 122 is provided with two driving units (not shown) that rotationally drive each of the two galvanometer mirrors 122a and 122b to change the reflection angle, and each of these two driving units is electrically connected to the light reflection control unit 196.

[0046] Preferably, the galvanometer units 121 and 122 can change the reflection angle corresponding to the repetition frequency of the laser beam L. That is, preferably, the first galvanometer mirror 121a, the second galvanometer mirror 121b, the third galvanometer mirror 122a, and the fourth galvanometer mirror 122b can vary the reflection angle in synchronization with the repetition frequency of the laser beam L. By doing so, the speed of the laser beam L scanning the target surface can be increased. In addition, the regions of a plurality of regions or cells 170 of the object to be processed can be sequentially or alternately irradiated at high speed with the laser beam L.

[0047] The ablation unit 100 of the present embodiment includes an objective lens reflecting mirror 151 that reflects the laser beam L reflected by the first galvanometer unit 121, and an fθ lens reflecting mirror 152 that reflects the laser beam L reflected by the second galvanometer unit 122. The objective lens reflecting mirror 151 reflects the laser beam L toward the objective lens 140. The fθ lens reflecting mirror 152 reflects the laser beam L toward the fθ lens 130.

[0048] The objective lens reflecting mirror 151 is preferably a dichroic mirror. The dichroic mirror reflects the laser beam L reflected by the first galvanometer unit 121 toward the objective lens 140 and transmits other light. By using the dichroic mirror as the objective lens reflecting mirror 151, the first camera 191 can be easily arranged to face the incident surface of the cell 170 as described later.

[0049] (Switching means) The ablation unit 100 of the present embodiment includes a first laser reflecting mirror 161 that reflects the laser beam L toward the first galvanometer unit 121, a second laser reflecting mirror 162 that reflects the laser beam L toward the second galvanometer unit 122, and a third laser reflecting mirror 163 that reflects the laser beam L emitted from the laser emitting unit 110 toward the first laser reflecting mirror 161 and the second laser reflecting mirror 162.

[0050] The second laser mirror 162 is disposed on the optical axis of the laser beam L reflected by the third laser mirror 163. The first laser mirror 161 is configured to move between on the optical axis of the laser beam L reflected by the third laser mirror 163 and outside the optical axis. That is, the first laser mirror 161 moves between a position where it reflects the laser beam L reflected by the third laser mirror 163 and a position where it does not reflect the laser beam L. When the first laser mirror 161 moves to a position where it reflects the laser beam L reflected by the third laser mirror 163 toward the first galvanometer unit, the laser beam L passes through the objective lens 140. When the first laser mirror 161 moves to a position where it does not reflect the laser beam L reflected by the third laser mirror 163, the laser beam L is reflected by the second laser mirror 162 and passes through the fθ lens 130. That is, the first laser mirror 161 is configured as an optical path switching means for the laser beam L. The ablation unit 100 can selectively perform ablation of the object by the laser beam L that has passed through the fθ lens 130 and ablation of the object by the laser beam L that has passed through the objective lens 140 by switching the optical path by moving the first laser mirror 161.

[0051] The means for moving the first laser mirror 161 between a position where it reflects the laser beam L reflected by the third laser mirror 163 and a position where it does not reflect the laser beam L is not particularly limited. For example, as shown in FIG. 2, the first laser mirror 161 may be configured to move in the X direction, or as shown in FIG. 3, the first laser mirror 161 may be rotated so as to deviate from the optical axis of the laser beam L reflected by the third laser mirror 163.

[0052] The stage 180 can move between a first position where the object to be ablated is ablated by the objective lens 140 (see FIG. 1) and a second position where the object to be ablated is ablated by the fθ lens 130 (see FIG. 2). That is, the ablation unit 100 has stage moving means (not shown) for moving the stage 180 between the first position and the second position. The stage moving means is not particularly limited, and for example, the stage 180 may be disposed on a known single-axis stage.

[0053] Preferably, the switching means and the stage moving means are configured to operate in synchronization with each other. That is, when the first laser mirror 161 moves to a position where it reflects the laser beam L toward the first galvanometer unit 121, the stage 180 is moved to the first position (on the optical axis of the laser beam L reflected by the objective lens mirror 151) by the stage moving means, and when the first laser mirror 161 moves to a position where it does not reflect the laser beam L toward the first galvanometer unit, the stage 180 is preferably moved to the second position (on the optical axis of the laser beam L reflected by the fθ lens mirror 152) by the stage moving means.

[0054] (Image processing unit) The ablation unit 100 includes an image processing unit 190 including cameras 191, 192, 193 for imaging the object to be ablated and a monitor 195 for displaying images of these cameras 191, 192, 193. The image processing unit 190 of the present embodiment includes a first camera 191 for imaging the object to be ablated by the objective lens 140, second and third cameras 192 and 193 as fθ lens cameras for imaging the object to be ablated by the fθ lens 130, and a monitor 195 for displaying images captured by these cameras 191, 192, 193. The monitor 195 may be, for example, a display screen of a personal computer. The monitor 195 is a device (e.g., a touch panel, etc.) capable of input by touching the screen. The operator designates the area to be irradiated with the laser beam L by touching an arbitrary part of the target surface displayed on the monitor 195.

[0055] The first camera 191 and the objective lens 140 are preferably arranged on the axis of the laser beam L incident on the object to be imaged. In other words, the first camera 191 is preferably arranged to face the incident surface of the cell 170 across the objective lens 140 in the axial direction of the laser beam L incident on the object to be imaged. The first camera 191 of the present embodiment is arranged above the objective lens mirror 151 (on the side opposite to the side where the laser beam L is reflected) and on the extension line of the optical axis of the laser beam L passing through the objective lens 140. By doing so, the image captured by the first camera 191 from the normal direction of the target surface can be displayed on the monitor 195, so that the accuracy of region designation can be improved.

[0056] The second camera 192 may be arranged to have an angle with respect to the optical axis of the laser beam L passing through the fθ lens 130. That is, the second camera 192 may be arranged to image the object accommodated in the cell 170 obliquely.

[0057] The second camera 192 is a camera for positioning the object irradiated by the laser beam L passing through the fθ lens 130. That is, the operator positions the object while checking the image captured by the second camera 192 on the monitor 195.

[0058] The third camera 193 is a camera that captures an enlarged image of the target surface positioned by the second camera 192. The operator designates the irradiation region of the object while checking the image captured by the third camera 193 on the monitor 195. The third camera 193 captures an image that is enlarged compared to the image captured by the second camera 192. That is, the third camera 193 captures an enlarged image of a part of the region captured by the second camera 192.

[0059] The third camera 193 is arranged between the fθ lens 130 and the cell 170 such that the imaging direction (the direction in which the third camera 193 captures the subject) is orthogonal to the optical axis of the laser beam L that irradiates the object to be imaged. A periscope 194 for reflecting the object to be imaged by approximately 90° is arranged in the imaging direction of the third camera 193. That is, the third camera 193 images the object to be imaged via the periscope 194 that changes the position (orientation) of the viewpoint by approximately 90°.

[0060] The periscope 194 includes a reflecting mirror, a prism, a lens, and the like. The periscope 194 preferably includes a telecentric lens. The periscope 194 is arranged to be movable in the imaging direction (X direction) of the third camera 193. The means for moving the periscope 194 in the X direction is not particularly limited. For example, a drive source (such as a motor) may be mounted on the periscope 194, the periscope 194 may be arranged on a one-axis stage, or it may be a manual operation by an operator.

[0061] The operator positions the object to be imaged while checking the image captured by the second camera 192, and moves the periscope 194 so that the object to be imaged can be captured by the third camera 193. Subsequently, the irradiation area is specified on the monitor 195 while checking the image captured by the third camera 193 via the periscope 194 (see FIG. 3). After specifying the irradiation area, the periscope 194 is moved to a position outside the optical axis of the laser beam L, and the irradiation with the laser beam L is started (see FIG. 2). By doing so, the object to be imaged can be easily positioned, and the accuracy of specifying the irradiation area of the object to be ablated by the fθ lens 130 can be improved. In FIG. 3, the laser beam L transmitted through the fθ lens 130 and the periscope 194 moved on its optical axis are depicted as reference figures.

[0062] (Optical reflection control unit) The light reflection control unit 196 controls the light reflection unit so that the laser beam L is irradiated onto the specified area. That is, the light reflection control unit 196 controls the galvanometer units 121 and 122 so that the laser beam L is irradiated onto the specified area. Specifically, the light reflection control unit 196 controls the drive units of the galvanometer units 121 and 122 so that the laser beam L is reflected onto the area specified by the operator touching the monitor 195. The light reflection control unit 196 is not particularly limited, and examples thereof include a personal computer. In the present embodiment, a personal computer is used as the light reflection control unit 196, and its display unit is used as the monitor 195 of the image processing unit 190. The light reflection control unit and the image processing unit may be provided separately.

[0063] By using the ablation unit 100 having such a configuration, the ablation method can be easily performed. In the ablation method using the ablation unit 100, before the step of displaying, there are a step of arranging the cell 170 containing the object to be processed on the stage 180, and after this arranging step, a step of selecting either transmission through the fθ lens 130 of the laser beam L or transmission through the objective lens 140. Further, when analyzing the object to be processed using the ablation unit 100 and the analysis unit 200, after the step of ablating, there is a step of transporting the aerosol generated by ablation to the analysis unit 200.

[0064] 〔Arranging step〕 In the arranging step, the cell 170 containing the object to be processed is arranged on the stage 180. The cell 170 is preferably fixed so as not to move relative to the stage 180. A gas supply pipe P1 and a gas discharge pipe P2 are connected to the cell 170 arranged on the stage 180, and preparations for supplying and discharging the carrier gas are made.

[0065] 〔Selecting step〕 In the selecting step, either the transmission of the fθ lens 130 or the transmission of the objective lens 140 of the laser beam L is selected. The operator selects the fθ lens 130 or the objective lens 140 and places the stage 180 at the position of the selected lens. The transmission of the fθ lens 130 or the objective lens 140 of the laser beam L is switched by the switching means. When ablating a relatively wide area, a plurality of areas of the object to be treated, or areas of each of a plurality of objects to be treated, ablation can be efficiently performed by selecting the fθ lens 130. To perform ablation of a relatively narrow area, analysis in the depth direction of the object to be treated, or high-precision analysis of the object to be treated, it is preferable to select the objective lens 140.

[0066] 〔Displaying step〕 In the displaying step, images of the cameras 191, 192, and 193 that image the object to be treated are displayed on the monitor 195. Specifically, the object to be treated that is placed on the stage 180 and imaged by the first camera 191, the second camera 192, or the third camera 193 is displayed on the monitor 195. The object to be treated is preferably displayed on the monitor 195 until the irradiation of the laser beam L is completed. By doing so, the operator can observe the state of the object to be treated before and after the irradiation of the laser beam L and the situation where the object to be treated is being ablated.

[0067] 〔Specifying step〕 In the specifying step, the area of the object to be treated irradiated with the laser beam L is specified by tracing the image displayed on the monitor 195. That is, the area for analyzing the object to be treated is determined. Specifically, the area is specified by tracing the displayed object to be treated with a touch pen (not shown) or the like, and the laser beam L is irradiated to the specified area. The light reflection control unit 196 converts the area specified on the monitor 195 into coordinate information and controls the drive unit based on this coordinate information. Note that tracing means that a touch pen or the like moves on the monitor 195 while maintaining contact with the monitor 195, and also includes the case where a touch pen or the like contacts the monitor 195 at a single point.

[0068] In the above-specified process, a plurality of regions may be specified. By specifying a plurality of regions, for example, it is possible to irradiate a plurality of regions of the object to be measured with the laser beam L, or to irradiate one or a plurality of regions of each of the plurality of objects to be measured accommodated in the cell 170 with the laser beam L.

[0069] [Ablation step] In the ablation step, the specified region is irradiated with the laser beam L for ablation. The ablation step preferably includes a first irradiation procedure of irradiating the outer periphery of the edge portion in the specified region with the laser beam L and a second irradiation procedure of irradiating the specified region with the laser beam L after the first irradiation means. That is, before irradiating the specified region with the laser beam L, it is preferable to irradiate the outer periphery of the edge portion with the laser beam L to partially remove it with a certain width and depth. By doing so, when the edge portion of the specified region (irradiation region) is irradiated with the laser beam L, it is possible to suppress ablation of the region that is not specified (non-irradiation region). That is, it is possible to suppress aerosolization of the non-irradiation region simultaneously with aerosolization of the irradiation region. For this reason, the purity of the aerosol generated in the irradiation region can be improved, and the analysis accuracy of the specified region can be improved.

[0070] It is preferable to irradiate the laser beam L so that the depth of the ablation mark formed in the second irradiation procedure is shallower than the depth of the ablation mark formed in the first irradiation procedure. By doing so, when ablating the irradiation region, it is possible to further suppress ablation of the non-irradiation region at the same time.

[0071] The conditions such as the output, wavelength, condensing diameter, and pulse width of the laser beam L in the ablation step may be appropriately set according to the physical properties of the object to be measured, the analysis method, the analysis purpose, and the like. For example, when analyzing the contained elements with the object to be measured as a solid, by setting the laser beam L to a condensing diameter of 2 μm or less, a deep ultraviolet wavelength region, a pulse width of 600 femtoseconds or less, and a repetition frequency of 1 kHz or more, the analysis accuracy by the analysis unit 200 can be improved.

[0072] When the laser light L is a pulsed laser light and a plurality of regions are designated in the designation step, the pulsed laser light may be irradiated to each of the regions with a set number of pulses. That is, the number of pulses of the pulsed laser light L to be irradiated to each of the designated regions may be set, and one of the regions and the other of the regions may be partially ablated sequentially or alternately with the set number of pulses. That is, the plurality of regions may be ablated simultaneously with the set number of pulses.

[0073] Specifically, when two regions are designated in the above designation step, m 1 A first region is irradiated with m pulses. 1 +m including 1st time 2 The second region may be irradiated with m pulses of the pulsed laser light, and this may be repeated alternately to ablate the two regions in parallel. 1 A first region is irradiated with m pulses. 1 +m including 1st time 2 A second region is irradiated with m pulses. 1 +m 2 +m including 1st time 3 A third region may be ablated with a single pulse, and this may be repeated in sequence to ablate the three regions in parallel. 1 ,m 2 and m 3 is an integer equal to or greater than 1, and m 1 ,m 2 ,m 3 may be the same integer.

[0074] Ablation of multiple regions may be started and stopped sequentially, i.e., all ablation in one region may be completed before ablation in another region begins.

[0075] [Transporting step] In the conveying step, the aerosol generated by ablation is conveyed to the analysis unit 200. Specifically, the aerosol is discharged from the cell 170 together with the supplied carrier gas and conveyed to the analysis unit 200 through the gas discharge pipe P2. The analysis unit 200 analyzes the object to be analyzed by known analysis methods such as inductively coupled plasma mass spectrometry and high-frequency inductively coupled plasma optical emission spectrometry.

[0076] [Other Embodiments] The above embodiments do not limit the configuration of the present invention. Therefore, based on the description in this specification and common technical knowledge, it is possible to omit, replace, or add components of each part of the above embodiments, and all of them should be interpreted as belonging to the scope of the present invention.

[0077] The ablation method and the ablation unit are not limited to being used in the analysis unit. The ablation method and the ablation unit may be used, for example, in a laser processing machine that processes an object with laser light.

[0078] The ablation unit may be provided with another fθ lens (second fθ lens) upstream of the objective lens. That is, after the laser light passes through the second fθ lens, it may be configured to pass through the objective lens and ablate the object to be analyzed.

[0079] The ablation unit is not limited to the above-described configuration. For example, it may be provided with either an fθ lens or an objective lens, or it may be provided with two laser emission units for the fθ lens and the objective lens. Also, the number of objective lenses included in the ablation unit may be one. The stage may be immovable, or for example, it may have two stages, a first stage for the objective lens and a second stage for the fθ lens.

[0080] The ablation unit may be provided with other optical lenses such as imaging lenses, other optical mirrors such as half mirrors, and lighting devices for illuminating the object to be ablated, as long as the ablation of the object to be ablated is not inhibited.

Industrial Applicability

[0081] The ablation method according to one aspect of the present disclosure can be used for an ablation unit connected to an analysis unit that analyzes elements contained in an object to be ablated using laser light, etc., to perform efficient analysis.

Explanation of Signs

[0082] 10 Analysis unit 100 Ablation unit 110 Laser emission unit 121, 122 Galvano unit 121a First mirror 121b Second mirror 122a Third mirror 122b Fourth mirror 130 fθ lens 140 Objective lens 141 First objective lens 142 Second objective lens 143 Third objective lens 144 Lens holder 151 Mirror for objective lens 152 Mirror for fθ lens 161 First laser mirror 162 Second laser mirror 163 Third laser mirror 170 Cell 171 Gas supply port 172 Gas discharge port 180 Stage 190 Image processing unit 191 First camera 192 Second camera 193 Third camera 194 Periscope 195 Monitor 196 Light reflection control unit 200 Analysis unit L Laser light P1 Gas supply pipe P2 Gas discharge pipe

Claims

1. A unit that irradiates a surface of an object with a laser beam to ablate it, comprising: a laser emitting unit that emits a laser beam; an fθ lens that condenses the laser beam on the surface of the object; an optical reflection unit that reflects the laser beam to an arbitrary position; an imaging processing unit including a camera that images the object and a monitor that displays an image of the camera; an optical reflection control unit that controls the optical reflection unit so that the laser beam is irradiated to a region specified by tracing an image displayed on the monitor; and the imaging processing unit includes a positioning camera for positioning the object irradiated by the laser beam transmitted through the fθ lens and a region specifying camera for specifying a region irradiated by the laser beam on the positioned object, the ablation unit.

2. Further comprising an objective lens that condenses the laser beam on the surface of the object, the imaging processing unit further includes an objective lens camera that images the object irradiated by the laser beam transmitted through the objective lens, the ablation unit according to claim 1, wherein the objective lens camera and the objective lens are arranged on the axis of the laser beam incident on the object.

3. The region specifying camera is arranged such that its imaging direction is orthogonal to the optical axis of the laser beam irradiating the object, the ablation unit according to claim 1, wherein the imaging processing unit further includes a periscope that reflects the object 90° toward the region specifying camera.

4. The ablation unit according to claim 1, wherein the laser emitting unit has a femtosecond pulse laser oscillator capable of setting a repetition frequency of 1 kHz or more.

5. The optical reflection unit includes a galvanometer mirror, the ablation unit according to claim 4, wherein the galvanometer mirror changes a reflection angle corresponding to the repetition frequency.

6. The ablation unit according to any one of claims 1 to 5, wherein the wavelength of the laser beam is deep ultraviolet.

7. A method of ablating an object using the ablation unit according to any one of claims 1 to 5, comprising: a step of displaying an image of the region specifying camera that images the object on the monitor; a step of specifying a region of the object to be irradiated with the laser beam by tracing the image displayed on the monitor; a step of irradiating the specified region with the laser beam to ablate it An ablation method comprising **Claim 8** The ablation method according to claim 7, wherein a plurality of regions are specified in the step of specifying.

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