Ablation method and ablation unit

Abstract

An ablation method according to one aspect of the present disclosure comprises: a step for displaying, on a monitor, an image of a camera that captures images of an object; a step for designating a region of the object to which laser beam is to be directed by tracing the image displayed on the monitor; and a step for directing the laser beam to the designated region to ablate same.

Description

Ablation method and ablation unit

[0001] The present disclosure relates to ablation methods and ablation units.

[0002] An analytical unit is known that irradiates a target object with a laser beam and analyzes the elements contained in the target object. One such analytical unit includes an ablation unit that includes a laser beam emitted from a laser light source and an optical system that reflects the laser beam toward the target object, and an analyzer that performs analysis using an inductively coupled plasma method (International Publication No. WO 2019 / 202689).

[0003] International Publication No. 2019 / 202689

[0004] The analysis unit described in Patent Document 1 is said to be able to expand the range of analyzable positions on an object because the ablation unit can reflect laser light with two mirrors and move the irradiation position two-dimensionally. However, there is also a need to irradiate and analyze a partial or localized area of ​​an object with laser light, rather than the entire object. Such a partial or localized area may have a non-geometric shape.

[0005] In view of the above-mentioned circumstances, an object of the present disclosure is to provide an ablation method that allows for easy and highly flexible determination of the region of an object to be irradiated with laser light.

[0006] An ablation method according to one aspect of the present disclosure, which has been made to solve the above problem, includes the steps of displaying an image of a camera capturing an image of an object on a monitor, specifying an area of ​​the object to be irradiated with laser light by tracing the image displayed on the monitor, and irradiating the specified area with laser light to ablate it.

[0007] An ablation method according to one aspect of the present disclosure allows for easy and highly flexible determination of the area of ​​the object to be irradiated with laser light.

[0008] Fig. 1 is a schematic side view showing a state in which laser light of an ablation unit according to an embodiment of the present disclosure passes through an objective lens. Fig. 2 is a schematic side view showing a state in which laser light of the ablation unit of Fig. 1 passes through an fθ lens. Fig. 3 is a schematic side view showing a state in which laser light of the ablation unit of Fig. 1 passes through an fθ lens in a manner different from that of Fig. 2.

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

[0010] (1) An ablation method according to one aspect of the present disclosure includes the steps of: displaying an image of a camera capturing an image of an object on a monitor; designating an area of ​​the object to be irradiated with laser light by tracing the image displayed on the monitor; and irradiating the designated area with laser light to ablate it.

[0011] This ablation method allows the user to specify the area to be irradiated with laser light by tracing the image of the object displayed on the monitor, and therefore the area can be easily determined with a high degree of freedom, regardless of whether it has a geometric or non-geometric shape, allowing for efficient ablation of the desired area of ​​the object.

[0012] (2) In the above (1), a plurality of regions may be designated in the designating step. This ablation method allows the region to be determined with a high degree of freedom, so that even when a plurality of regions are designated, the region 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 with laser light to ablate it, and includes a laser emitting unit that emits laser light, a light reflecting unit that reflects the laser light to any position, an image processing unit that includes a camera that captures an image of the object and a monitor that displays the image from the camera, and a light reflection control unit that controls the light reflecting unit so that the laser light is irradiated to an area specified by tracing the image displayed on the monitor.

[0014] The ablation unit is equipped with a light reflecting section that reflects the laser light to any position, and a light reflection control section that controls the light reflecting section so that the laser light is irradiated onto a specified area by tracing an image displayed on a monitor.Therefore, the area to be irradiated with the laser light can be easily determined with a high degree of freedom, and the laser light can be irradiated onto this area efficiently.

[0015] (4) In the above (3), the ablation unit may further include an objective lens that focuses the laser light on the surface of the object, and the camera and the objective lens may be arranged on the axis of the laser light that enters the object. By arranging the camera and the objective lens on the axis of the laser light that enters the object, it is possible to easily capture an image of the object and improve the accuracy of specifying the irradiation area.

[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, and an fθ lens camera that captures an image for specifying an area to be irradiated with the laser light that passes through the fθ lens. By including the fθ lens in the ablation unit, a relatively large area of ​​the object can be easily ablated. By including the fθ lens camera in the ablation unit, the accuracy of specifying the irradiation area can be improved.

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

[0018] (7) In the above (6), the light reflecting section may include a galvanometer mirror, and the galvanometer mirror may change the reflection angle in response to the repetition frequency. By including a galvanometer mirror whose reflection angle can be changed in response to the repetition frequency in the light reflecting section, more efficient ablation can be achieved.

[0019] (8) In any one of (3) to (7) above, the wavelength of the laser light may be deep ultraviolet. By using a wavelength of the laser light in the deep ultraviolet range, more efficient ablation can be achieved.

[0020] It should be noted that the region includes points (caused by one ablation) and lines (continuous straight lines, curved lines, and combinations thereof caused by multiple ablations).

[0021] [Details of the embodiment of the present disclosure] Hereinafter, the embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the drawings are illustrative of the embodiment, and the shape, size, scale, arrangement, etc. of each component (member) may differ from the actual ones.

[0022] <Ablation Method> This ablation method includes the steps of: displaying an image of a camera capturing an object on a monitor; designating an area of ​​the object to be irradiated with laser light by tracing the image displayed on the monitor; and irradiating the designated area with laser light to ablate it. The object is not particularly limited and may be a solid or liquid object, but this ablation method is particularly suitable for solid objects.

[0023] The ablation method can be performed using, for example, an ablation unit 100 shown in Figures 1, 2, and 3. The ablation unit 100 is connected to, for example, an analysis unit 200 that performs elemental analysis, and analyzes the elements contained in a target object (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 atomic emission spectrometry.

[0025] [Ablation Unit] The ablation unit 100 includes a laser emission unit 110 that emits laser light L (shown by a dot-dash line in each figure), a light reflection unit that reflects the laser light L to any position, an image processing unit 190 that includes cameras 191, 192, and 193 that capture images of an object (not shown) and a monitor 195 that displays images from the cameras 191, 192, and 193, and a light reflection control unit 196 that controls the light reflection unit so that the laser light L is irradiated onto a specified area by tracing the image displayed on the monitor 195.

[0026] (Cell) The target object is housed in a cell 170 and irradiated with the laser light L. The cell 170 is a container that houses one or more target objects and prevents the aerosol generated by ablation from scattering. A transparent plate (not shown) through which the laser light 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 light L.

[0027] The cell 170 has a gas supply port 171 through which a carrier gas that transports the aerosol to the analysis unit 200 is supplied, and a gas exhaust port 172 through which the carrier gas containing the aerosol is exhausted. A gas supply pipe P1 is connected to the gas supply port 171, and a gas exhaust pipe P2 is connected to the gas exhaust port 172.

[0028] The surface of the object contained in the cell 170 is irradiated with laser light L to ablate it, thereby partially aerosolizing the object. Specifically, the surface of the object is vaporized by irradiation with laser light L, and a portion of the vaporized material is ionized. The laser light L then penetrates the object to a depth of several nanometers to several micrometers from the surface and releases most of its energy, vaporizing and fragmenting the object's constituent components. This ablation releases the ionized and vaporized elements, some of which recondense into solid particles, and fragmented fragments from the object as an aerosol. The aerosol is transported to the analysis unit 200 via the gas exhaust pipe P2 by a carrier gas, such as helium, supplied into the cell 170, where the chemical composition of the object is analyzed.

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

[0030] The means for preventing the cell 170 from moving relative to the stage 180 is not particularly limited, and may be fixed with bolts, pins, or the like, but is preferably fixed by magnetic force. Specifically, it is preferable that a magnet (not shown) is placed on the stage 180, and the cell 170, which is made of a magnetic material such as metal, is fixed by the magnetic force of the magnet. A coil (not shown) that generates a magnetic force when energized may also be placed on the stage 180. The magnet or the coil may be placed on the cell 170, or may be placed on both the stage 180 and the cell 170. It is preferable that a guide portion (not shown) is provided on the mounting surface of the stage 180 to determine the position at which the cell 170 is placed.

[0031] The stage 180 is preferably capable of moving the cell 170 in the axial direction (Z direction) of the laser light L incident on the object, and in two directions (X direction and Y direction) that are perpendicular to this axial direction and perpendicular to each other. In other words, it is preferable that the mounting surface of the stage 180 is movable in the X-Y-Z directions. This makes it possible to easily adjust the irradiation position of the laser light L on the object in the X-, Y-, and Z-directions.

[0032] The Z-direction movement means (height adjustment means) on the mounting surface of the stage 180 is not particularly limited, but is preferably configured to be adjustable by piezoelectric element drive. The upper limit of the minimum movement unit (resolution) for the Z-direction movement is preferably 5 nm, more preferably 2 nm, and even more preferably 1 nm. The lower limit 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 focusing position of the laser light L in the Z direction can be efficiently determined. In other words, the focus of the fθ lens 130 and the objective lens 140, the depth to which the laser light L penetrates the object, and the like can be adjusted with high precision, resulting in efficient aerosolization and improved analysis accuracy by the analysis unit 200. The stage 180 may be a goniostage capable of changing the angle in the X-Y plane.

[0033] (Laser Emitter) The laser emitter 110 emits laser light L to irradiate the surface of the target object (hereinafter also referred to as the target surface). The laser emitter 110 includes a known laser oscillator (not shown), such as a solid-state laser, a semiconductor laser, or a gas laser. The wavelength range of the laser light L can preferably be set arbitrarily. The wavelength of the laser light L is preferably deep ultraviolet. That is, the laser emitter 110 can preferably set the wavelength range of the laser light L to deep ultraviolet. Specifically, the wavelength of the laser light L can preferably be set to 280 nm or less, more preferably 270 nm or less, and even more preferably 260 nm or less. The lower limit of the wavelength that can be set is not particularly limited and may be, for example, 100 nm. Irradiating the target surface with laser light L having a deep ultraviolet wavelength can promote the reduction of aerosol (fragments) by ablation.

[0034] The laser light L emitted from the laser emission unit 110 may be a continuous wave, but is preferably a pulse wave. The pulse width of the pulse wave of the laser light L emitted from the laser emission unit 110 can preferably be set arbitrarily. The pulse width can preferably be set to 600 femtoseconds or less, and more preferably 300 femtoseconds or less. By irradiating the target surface with laser light L having such a pulse width, it is possible to further promote the aerosol micronization by ablation.

[0035] By setting the wavelength and pulse width of the laser light L within the above ranges, the absorption efficiency of the energy of the laser light L (laser energy) on the target surface is improved, and if the target object is a solid object, the depth to which the laser light L penetrates into the surface (surface layer) of the target object is reduced. In other words, the laser energy can be absorbed in a small volume.

[0036] When a solid object is analyzed (e.g., for the analysis of contained elements), irradiating the solid object with laser light L having a deep ultraviolet wavelength and a short pulse of 600 femtoseconds or less improves the absorption efficiency of laser energy on the surface of the solid object, thereby reducing the depth of the ablation marks. Specifically, the depth of the ablation marks can be controlled in nanometer units. By reducing the depth of the ablation marks, accurate analysis of the depth direction of the solid object can be performed. In other words, a precise depth profile of the solid object can be obtained. Note that the ablation marks (also called spots, craters, etc.) refer to grooves (holes) formed in a solid object by ablation with laser light.

[0037] Furthermore, efficient absorption of laser energy by the surface of the solid object promotes the fragmentation of fragments broken up at the surface, improving aerosolization and ultimately improving the analytical accuracy by the analysis unit 200. Specifically, the average particle size of the fragments broken up at the surface can be set to 400 nm or less, or 300 nm or less, or 200 nm or less. This promotes ionization of the fragments by plasma in the analysis unit 200, improving the analytical accuracy. The average particle size means the particle size at 50% of the integrated value in the particle size distribution determined by the laser diffraction scattering method.

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

[0039] (Lens) The ablation unit 100 has a lens that adjusts the focused diameter of the laser light L on the target surface. The ablation unit 100 of this embodiment includes an fθ lens 130 and an objective lens 140 so that the focused diameter of the laser light L can be selected arbitrarily. In the laser ablation unit 100 of this embodiment, the fθ lens 130 and the objective lens 140 are arranged parallel to each other in the X direction. The fθ lens 130 focuses the laser light L on the surface of the target object with a relatively large focused diameter, while the objective lens 140 focuses the laser light L with a smaller focused diameter than the fθ lens 130. A beam expander lens (not shown) that expands the beam diameter may be arranged upstream of the fθ lens 130 and the objective lens 140.

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

[0041] The focused diameter of the laser light L by at least one objective lens 140 is preferably 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 focused diameter of the laser light L on the target surface 2 μm or less. The upper limit of the focused diameter at the above magnification is more preferably 1.5 μm, even more preferably 1.0 μm, and particularly preferably 0.5 μm. By irradiating the target surface with the laser light L at such a focused diameter, precise ablation can be performed. The lower limit of the focused diameter at the above magnification is not particularly limited and may be, for example, 0.1 μm.

[0042] Specifically, it is preferable to select the lens magnification so that the focused light diameter is 0.5 μm for the first objective lens 141, 3.0 μm for the second objective lens 142, and 5.0 μm for the third objective lens 143. The lens magnifications of the three objective lenses 141, 142, and 143 may be, for example, 60x, 40x, 20x, or 50x, 20x, 10x, etc. The focused light diameter of the fθ lens 130 may be, for example, 10 μm. In this way, the focused light diameter on the target surface can be arbitrarily selected using multiple lenses, allowing ablation to be performed according to the purpose of analysis, the characteristics of the target object, etc.

[0043] (Light Reflecting Unit) The light reflecting unit reflects the laser light L so that the laser light L irradiates a desired position on the target surface. That is, the light reflecting unit controls the irradiation position of the laser light L on the target surface. The light reflecting unit is not particularly limited, but is preferably galvano units 121 and 122 including a galvanometer mirror. The ablation unit 100 of this embodiment has a first galvano unit 121 that controls the irradiation position of the laser light L passing through the objective lens 140, and a second galvano unit 122 that controls the irradiation position of the laser light L passing through the fθ lens 130. By using such galvano units 121 and 122, the laser light L passing through the fθ lens 130 and the objective lens 140 can be moved to a desired position on the target surface, making it easy to ablate a desired area of ​​the target surface.

[0044] The first galvanometer unit 121 has a first galvanometer mirror 121a and a second galvanometer mirror 121b. Each of the two galvanometer mirrors 121a and 121b has a driver (not shown) that changes the reflection angle by being rotated. That is, the first galvanometer unit 121 has two drivers. Each of these two drivers is electrically connected to the light reflection control unit 196. The first galvanometer mirror 121a reflects the laser light 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 light L reflected by the first galvanometer mirror 121a and moves the irradiation position in a direction (Y direction) perpendicular to the one direction.

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

[0046] It is preferable that the galvanometer units 121 and 122 can change the reflection angle in accordance with the repetition frequency of the laser light L. That is, it is preferable that the first galvanometer mirror 121a and the second galvanometer mirror 121b and the third galvanometer mirror 122a and the fourth galvanometer mirror 122b can change the reflection angle in synchronization with the repetition frequency of the laser light L. This makes it possible to increase the speed of the laser light L scanning the target surface. Furthermore, it is possible to sequentially or alternately irradiate multiple regions of the target object or respective regions of multiple target objects contained in the cell 170 with the laser light L at high speed.

[0047] The ablation unit 100 of this embodiment has an objective lens reflecting mirror 151 that reflects the laser light L reflected by the first galvano section 121, and an fθ lens reflecting mirror 152 that reflects the laser light L reflected by the second galvano section 122. The objective lens reflecting mirror 151 reflects the laser light L toward the objective lens 140. The fθ lens reflecting mirror 152 reflects the laser light L toward the fθ lens 130.

[0048] The objective lens reflecting mirror 151 is preferably a dichroic mirror. The dichroic mirror reflects the laser light L reflected by the first galvano unit 121 toward the objective lens 140 and transmits other light. By using a dichroic mirror as the objective lens reflecting mirror 151, it is possible to easily position the first camera 191 so as to face the entrance surface of the cell 170, as will be described later.

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

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

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

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

[0053] It is preferable that the switching means and the stage moving means are configured to operate in synchronization with each other. That is, when the first laser reflecting mirror 161 moves to a position where it reflects the laser light L toward the first galvano unit 121, the stage 180 is moved to the first position (on the optical axis of the laser light L reflected by the objective lens reflecting mirror 151) by the stage moving means, and when the first laser reflecting mirror 161 moves to a position where it does not reflect the laser light L toward the first galvano unit, the stage 180 is moved to the second position (on the optical axis of the laser light L reflected by the fθ lens reflecting 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, and 193 that capture images of the target object and a monitor 195 that displays images of the cameras 191, 192, and 193. In this embodiment, the image processing unit 190 includes a first camera 191 that captures images of the target object to be ablated by the objective lens 140, a second camera 192 and a third camera 193 as fθ lens cameras that capture images of the target object to be ablated by the fθ lens 130, and a monitor 195 that displays images captured by these cameras 191, 192, and 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) that allows input by touching the screen. The operator designates an area to be irradiated with the laser light L by touching any part of the target surface displayed on the monitor 195.

[0055] The first camera 191 and the objective lens 140 are preferably disposed on the axis of the laser light L incident on the object. In other words, the first camera 191 is preferably disposed in the axial direction of the laser light L incident on the object so as to face the incident surface of the cell 170 across the objective lens 140. The first camera 191 of this embodiment is disposed above the objective lens reflector 151 (the side opposite to where the laser light L is reflected) on an extension of the optical axis of the laser light L passing through the objective lens 140. This allows the image captured by the first camera 191 from the normal direction of the object surface to be displayed on the monitor 195, thereby improving the accuracy of area designation.

[0056] The second camera 192 may be disposed at an angle with respect to the optical axis of the laser light L passing through the fθ lens 130. In other words, the second camera 192 may be disposed so as to capture an image of the object housed in the cell 170 from an oblique angle.

[0057] The second camera 192 is a camera for determining the position of an object to be irradiated with the laser light L transmitted through the fθ lens 130. That is, the operator determines the position of the object while checking the image captured by the second camera 192 on the monitor 195.

[0058] Third camera 193 is a camera that captures an enlarged image of the target surface positioned by second camera 192. The worker specifies the irradiation area of ​​the target object while checking the image captured by third camera 193 on monitor 195. Third camera 193 captures an enlarged image compared to that captured by second camera 192. In other words, third camera 193 captures an enlarged image of a portion of the area captured by second camera 192.

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

[0060] The periscope 194 includes a reflecting mirror, a prism, a lens, etc. The periscope 194 preferably includes a telecentric lens. The periscope 194 is disposed so as to be movable in the image capturing direction (X direction) of the third camera 193. The means for moving the periscope 194 in the X direction is not particularly limited, and for example, the periscope 194 may be equipped with a drive source (such as a motor), the periscope 194 may be disposed on a one-axis stage, or the periscope 194 may be manually operated by an operator.

[0061] The operator positions the target object while checking the image captured by the second camera 192 and moves the periscope 194 so that the target object can be imaged by the third camera 193. Next, while checking the image captured by the third camera 193 through the periscope 194, the operator specifies the irradiation area on the monitor 195 (see FIG. 3 ). After specifying the irradiation area, the operator moves the periscope 194 so that it is positioned outside the optical axis of the laser light L, and irradiation with the laser light L begins (see FIG. 2 ). This arrangement facilitates positioning of the target object and improves the accuracy of specifying the irradiation area of ​​the target object to be ablated by the fθ lens 130. Note that FIG. 3 also illustrates, for reference, the laser light L passing through the fθ lens 130 and the periscope 194 moved to its optical axis.

[0062] (Light Reflection Control Unit) The light reflection control unit 196 controls the light reflection unit so that the laser light L is irradiated onto a designated area. That is, the light reflection control unit 196 controls the galvano units 121 and 122 so that the laser light L is irradiated onto the designated area. Specifically, the light reflection control unit 196 controls the drive units of the galvano units 121 and 122 so that the laser light L is reflected onto a designated area when the operator touches the monitor 195. The light reflection control unit 196 is not particularly limited, and examples thereof include a personal computer. In this embodiment, a personal computer is used as the light reflection control unit 196, and its display unit is the monitor 195 of the image processing unit 190. The light reflection control unit and the image processing unit may be provided separately.

[0063] The ablation method can be easily performed by using the ablation unit 100 having such a configuration. The ablation method using the ablation unit 100 includes, before the displaying step, a step of placing the cell 170 containing the object on the stage 180, and, after this placing step, a step of selecting whether the laser light L passes through the fθ lens 130 or the objective lens 140. Furthermore, when the object is analyzed using the ablation unit 100 and the analysis unit 200, a step of transporting the aerosol generated by the ablation to the analysis unit 200 is included after the ablation step.

[0064] [Placing Step] In the placing step, the cell 170 containing the object to be measured is placed 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 exhaust pipe P2 are connected to the cell 170 placed on the stage 180, and preparations are made for the supply and exhaust of a carrier gas.

[0065] [Selecting Step] In the selecting step, the laser light L is selected to be transmitted through either the fθ lens 130 or the objective lens 140. 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 switching means switches between transmitting the laser light L through the fθ lens 130 or the objective lens 140. When ablating a relatively wide area, multiple areas of the object, or each area of ​​multiple objects, selecting the fθ lens 130 enables efficient ablation. When ablating a relatively narrow area, analyzing the object in the depth direction, or analyzing the object with high precision, it is preferable to select the objective lens 140.

[0066] [Displaying Step] In the displaying step, images from cameras 191, 192, and 193 that capture images of the object are displayed on monitor 195. Specifically, the object that is placed on stage 180 and captured by first camera 191, second camera 192, or third camera 193 is displayed on monitor 195. It is preferable that the object is displayed on monitor 195 until irradiation of laser light L is completed. In this way, the operator can observe the state of the object before and after irradiation with laser light L, and the state of the object being ablated.

[0067] [Designation Step] In the designation step, the area of ​​the object to be irradiated with the laser light L is designated by tracing the image displayed on the monitor 195. That is, the area of ​​the object to be analyzed is determined. Specifically, the area is designated by tracing the displayed object with a touch pen (not shown) or the like, and the laser light L is irradiated onto this designated area. The light reflection control unit 196 converts the area designated on the monitor 195 into coordinate information and controls the drive unit based on this coordinate information. Note that tracing means moving the touch pen or the like across the monitor 195 while maintaining contact with the monitor 195, and includes contacting the touch pen or the like with the monitor 195 at a single point.

[0068] In the above-described designation step, multiple regions may be designated. By designating multiple regions, for example, it is possible to irradiate multiple regions of the object with the laser light L, or to irradiate one or multiple regions of each of multiple objects contained in the cell 170 with the laser light L.

[0069] [Ablation Step] In the ablation step, the designated region is ablated by irradiating it with laser light L. The ablation step preferably includes a first irradiation step of irradiating the outer periphery of the edge of the designated region with laser light L, and a second irradiation step of irradiating the region with laser light L after the first irradiation step. That is, before irradiating the region with laser light L, it is preferable to irradiate the outer periphery of the edge with laser light L to partially remove a certain width and depth. By doing so, when irradiating the edge of the designated region (irradiation region) with laser light L, ablation of the non-designated region (non-irradiation region) can be suppressed. That is, aerosolization of the irradiated region can be suppressed simultaneously with aerosolization of the non-irradiation region. This improves the purity of the aerosol generated in the irradiation region and improves the analytical accuracy of the designated region.

[0070] It is preferable to irradiate the laser light L so that the depth of the ablation scar formed in the second irradiation procedure is shallower than the depth of the ablation scar formed in the first irradiation procedure. In this way, when ablating the irradiated area, ablation of the non-irradiated area can be further suppressed.

[0071] The conditions of the laser light L in the ablation step, such as the output, wavelength, focused diameter, and pulse width, may be set appropriately depending on the physical properties of the object, the analysis method, the purpose of the analysis, etc. For example, when the object is a solid object and the elements contained therein are analyzed, the analytical accuracy of the analysis unit 200 can be improved by setting the laser light L to a focused diameter of 2 μm or less, a wavelength region in the deep ultraviolet, a pulse width of 600 femtoseconds or less, and a repetition frequency of 1 kHz or more.

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

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

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

[0075] In the transporting step, the aerosol generated by ablation is transported to the analysis unit 200. Specifically, the aerosol is discharged from the cell 170 together with the supplied carrier gas, and is transported to the analysis unit 200 through the gas exhaust pipe P2. The analysis unit 200 analyzes the object of interest using a known analysis method such as inductively coupled plasma mass spectrometry or high frequency inductively coupled plasma atomic emission spectrometry.

[0076] [Other Embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as falling within the scope of the present invention.

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

[0078] The ablation unit may include another fθ lens (second fθ lens) upstream of the objective lens, i.e., the laser light may be configured to pass through the second fθ lens, and then pass through the objective lens to ablate the object.

[0079] The ablation unit is not limited to the above-described configuration. For example, it may be one that includes either an fθ lens or an objective lens, or one that includes two laser emission units, one for the fθ lens and one for the objective lens. The ablation unit may also have only one objective lens. The stage may be immovable, and may have two stages, for example, a first stage for the objective lens and a second stage for the fθ lens.

[0080] The ablation unit may also include other optical lenses such as an imaging lens, other optical mirrors such as a half mirror, and an illumination device for illuminating the object, as long as the ablation of the object is not hindered.

[0081] An ablation method according to one aspect of the present disclosure can be used in an ablation unit connected to an analysis unit that uses laser light to analyze elements contained in a target object, thereby enabling efficient analysis.

[0082] 10 Analysis unit 100 Ablation unit 110 Laser emission section 121, 122 Galvano section 121a First reflecting mirror 121b Second reflecting mirror 122a Third reflecting mirror 122b Fourth reflecting mirror 130 fθ lens 140 Objective lens 141 First objective lens 142 Second objective lens 143 Third objective lens 144 Lens holder 151 Reflecting mirror for objective lens 152 Reflecting mirror for fθ lens 161 First laser reflecting mirror 162 Second laser reflecting mirror 163 Third laser reflecting mirror 170 Cell 171 Gas supply port 172 Gas exhaust port 180 Stage 190 Image processing section 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 exhaust pipe

Claims

1. An ablation method comprising the steps of: displaying on a monitor an image taken by a camera capturing an image of an object; specifying an area of ​​the object to be irradiated with laser light by tracing the image displayed on the monitor; and irradiating the specified area with laser light to ablate it.

2. The ablation method according to claim 1, wherein a plurality of regions are designated in said designating step.

3. A unit for ablating the surface of an object by irradiating it with laser light, comprising: a laser emission unit that emits laser light; a light reflection unit that reflects the laser light to any desired position; an image processing unit including a camera that captures an image of the object and a monitor that displays the image from the camera; and a light reflection control unit that controls the light reflection unit so that the laser light is irradiated to a specified area by tracing the image displayed on the monitor.

4. An ablation unit as described in claim 3, further comprising an objective lens for focusing the laser light on the surface of the object, said camera and said objective lens being arranged on the axis of said laser light incident on the object.

5. The ablation unit described in claim 3, further comprising: an fθ lens that focuses the laser light on the surface of the object; and an fθ lens camera that captures an image for specifying an area to be irradiated with the laser light passing through the fθ lens.

6. The ablation unit according to claim 3, wherein said laser emission section has a femtosecond pulse laser oscillator capable of setting the repetition frequency to 1 kHz or more.

7. The ablation unit according to claim 6, wherein the light reflecting portion includes a galvanometer mirror, and the galvanometer mirror changes the reflection angle in response to the repetition frequency.

8. An ablation unit according to any one of claims 3 to 7, wherein the wavelength of the laser light is deep ultraviolet.

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