Method for using microscope device

Abstract

This method for using a microscope device comprises: a first step for disposing a sample in a chamber; a second step for reducing the pressure in the chamber by evacuating the chamber; a third step for, after the first step and the second step, removing part of the sample by performing ablation processing by irradiating the sample in the chamber with laser light through a transmission member that transmits the laser light; a fourth step for, after the first step and the second step, performing ablation processing on particles generated from the sample by irradiation with the laser light in a state where the sample is disposed in the chamber; and a fifth step for, after the third step, observing the sample using a microscope unit.

Description

How to use the microscope equipment

[0001] The present disclosure relates to a method of using a microscope apparatus.

[0002] Patent Document 1 describes a laser processing method. In this method, a workpiece is held in a vacuum chamber. The vacuum chamber is provided with a window that transmits a laser beam. A laser beam emitted from a laser light source passes through the window and is incident on the workpiece. This causes an etching phenomenon called ablation on the surface of the workpiece, and the surface of the workpiece is removed.

[0003] Japanese Patent Application Laid-Open No. 2002-248589

[0004] As in the laser processing method described in Patent Document 1, there is a demand for ablation processing of a sample by irradiating the sample with laser light through a transparent member such as a window of a vacuum container. When ablation processing of a sample is performed, particles may be generated from the sample and adhere to the transparent member. If ablation processing is continued in a situation where particles are adhering to the transparent member, the transmittance of the laser light through the transparent member may decrease, which may result in a decrease in processing quality or may cause unintended absorption of the laser light in the transparent member, resulting in damage to the transparent member.

[0005] An object of the present disclosure is to provide a method of using a microscope apparatus that can suppress a decrease in the transmittance of a transmitting member.

[0006] A method of using a microscope apparatus according to the present disclosure is [1] a method of using a microscope apparatus comprising: a first step of placing a sample in a chamber; a second step of evacuating the chamber to reduce the pressure inside the chamber; a third step of, after the first and second steps, performing ablation processing by irradiating the sample in the chamber with laser light through a transparent member that transmits the laser light to remove a portion of the sample; a fourth step of, after the first and second steps, performing ablation processing of particles generated from the sample by irradiating the sample with the laser light in a state in which the sample is placed in the chamber; and a fifth step of observing the sample using a microscope unit after the third step, wherein in the third step, a focal point of the laser light is positioned at a first position closer to the sample than the transparent member in the optical axis direction of the laser light, and in the fourth step, the focal point is positioned at a second position closer to the transparent member than the sample in the optical axis direction.

[0007] In this method of using a microscope apparatus, a sample is placed in a chamber, the chamber is depressurized, and then ablation processing of the sample is performed by irradiating the sample with laser light through a transparent member. Therefore, particles generated during the ablation processing may adhere to the transparent member (or may have already adhered to the transparent member). In contrast, this method performs ablation processing of particles generated from the sample by irradiating the sample with laser light. This can prevent particles from adhering to the transparent member and remove particles attached to the transparent member. This can prevent a decrease in the transmittance of the transparent member. Note that this method performs ablation processing when processing the sample and particles generated from the sample. Therefore, compared to when thermal processing is performed using laser light during sample processing, damage to the sample during processing is reduced, and even when laser light is irradiated onto the sample during processing of particles generated from the sample, damage to the sample is less likely to occur. Therefore, this method can prevent a decrease in the transmittance of the transparent member while suppressing damage to the sample.

[0008] The method of using the microscope apparatus according to the present disclosure may be [2] "the method of using the microscope apparatus described in [1] above, in which the fourth step is performed after the third step." In this case, particles generated from the sample in the previous third step and deposits attached to the transmitting member can be removed in the subsequent fourth step.

[0009] The method of using the microscope apparatus according to the present disclosure may be [3] "the method of using the microscope apparatus described in [2] above, in which the third step is performed again after the fourth step." In this case, for example, it is possible to remove the deposit removed from the transmitting member in the fourth step and attached to the sample by performing the third step again.

[0010] The method of using the microscope apparatus according to the present disclosure may be [4] "the method of using the microscope apparatus according to any one of [1] to [3] above, in which the position of the focal point is changed between the first position and the second position by moving the chamber between the third step and the fourth step." In this case, by moving the chamber, it is possible to change the position of the focal point of the laser light between the first position in the third step and the second position in the fourth step.

[0011] The method of using the microscope apparatus according to the present disclosure may be [5] "the method of using the microscope apparatus according to any one of [1] to [4] above, in which, between the third step and the fourth step, a lens for focusing the laser light toward the sample or the transparent member is moved, thereby changing the position of the focusing point between the first position and the second position." In this case, by moving the lens, it is possible to change the position of the focusing point of the laser light between the first position in the third step and the second position in the fourth step.

[0012] The method of using the microscope apparatus according to the present disclosure may be [6] "the method of using the microscope apparatus according to any one of [1] to [5] above, wherein, between the third step and the fourth step, a galvanometer scanner is used to change the position of the focal point between the first position and the second position." In this case, by using the galvanometer scanner, it is possible to change the position of the focal point of the laser light between the first position in the third step and the second position in the fourth step.

[0013] The method of using the microscope apparatus according to the present disclosure may be [7] "the method of using the microscope apparatus according to any one of the above [1] to [6], in which, between the third step and the fourth step, a spatial light modulator is used to change the position of the focal point between the first position and the second position." In this case, by using the spatial light modulator, it is possible to change the position of the focal point of the laser light between the first position in the third step and the second position in the fourth step.

[0014] The method of using the microscope apparatus according to the present disclosure may be [8] "the method of using the microscope apparatus according to the above [1], in which the fourth step is performed simultaneously with the third step." In this case, it is possible to shorten the processing time by simultaneously processing the sample and particles generated from the sample.

[0015] The method of using the microscope apparatus according to the present disclosure may be [9] "the method of using the microscope apparatus described in the above [8], in which the third step and the fourth step are performed simultaneously by modulating the laser light with a spatial light modulator to form the focal points at both the first position and the second position." In this case, it is possible to preferably simultaneously process the sample and particles generated from the sample.

[0016] The method of using the microscope apparatus according to the present disclosure may be

[10] "the method of using the microscope apparatus according to any one of [1] to [9] above, wherein the pulse width of the laser light is 1 ps or less." In this case, it becomes possible to perform ablation processing effectively.

[0017] The method of using the microscope apparatus according to the present disclosure may be

[11] "the method of using the microscope apparatus according to any one of [1] to

[10] above, wherein the second position is a position within 2 mm from the surface of the transparent member facing the sample." In this way, by setting the position (second position) of the focal point of the laser light in the fourth step within 2 mm from the surface of the transparent member facing the sample, it is possible to ensure laser intensity sufficient to remove deposits on the surface of the transparent member.

[0018] The method of using the microscope apparatus according to the present disclosure may be

[12] "the method of using the microscope apparatus according to any one of [1] to

[11] above, wherein the second position is a position on the opposite side of the sample from the surface of the transparent member facing the sample." In this way, by moving the position (second position) of the focal point of the laser light in the fourth step further away from the sample, damage to the sample can be suppressed.

[0019] The method of using the microscope apparatus according to the present disclosure may be

[13] "the method of using the microscope apparatus described in the above

[12] , in which the second position is a position inside the transparent member." In this way, the position (second position) of the focal point of the laser light in the fourth step may be set inside the transparent member.

[0020] The method of using the microscope apparatus according to the present disclosure may be

[14] "the method of using the microscope apparatus described in

[12] above, in which the second position is a position outside the transparent member." In this way, by setting the position (second position) of the focal point of the laser light in the fourth step to outside the transparent member on the side opposite to the sample, it is possible to ensure a wider irradiation area of ​​the laser light on the surface of the transparent member facing the sample.

[0021] The method of using a microscope apparatus according to the present disclosure may be

[15] "the method of using a microscope apparatus according to any one of [1] to

[14] above, wherein in the fourth step, the laser light transmitted through the transparent member is irradiated onto the sample." As described above, in this method, the same laser light as that used for ablation processing of the sample is used to process particles generated from the sample, so even if part of the laser light irradiated onto the transparent member in the fourth step is irradiated onto the sample, damage to the sample is unlikely to occur. Therefore, in the fourth step, there is no need to move the sample or block the laser light so that part of the laser light is not irradiated onto the sample.

[0022] The method of using the microscope apparatus according to the present disclosure may be

[16] "the method of using the microscope apparatus according to any one of the above [1] to

[15] , wherein the transparent member is an incident portion of the laser light in the chamber." In this way, the transparent member from which the deposits are to be removed may be an incident portion of the laser light in the chamber.

[0023] The method of using the microscope apparatus according to the present disclosure may be

[17] "the method of using the microscope apparatus according to any one of the above [1] to

[15] , wherein the transparent member is a cover provided to cover the sample in the chamber." In this way, the transparent member from which the deposits are to be removed may be a cover provided to cover the sample.

[0024] The method of using the microscope apparatus according to the present disclosure may be

[18] "the method of using the microscope apparatus according to any one of [1] to

[17] above, in which the fourth step and the fifth step are performed in different chambers." In this way, the observation of the sample in the fifth step may be performed in a chamber different from the chamber in which the ablation processing of particles generated from the sample in the fourth step is performed.

[0025] The method of using the microscope apparatus according to the present disclosure may be

[19] "the method of using the microscope apparatus according to any one of [1] to

[17] above, in which the fourth step and the fifth step are performed in the same chamber." In this way, the observation of the sample in the fifth step may be performed in the same chamber as the chamber in which the ablation processing of particles generated from the sample in the fourth step is performed.

[0026] The method of using the microscope apparatus according to the present disclosure may be

[20] "the method of using the microscope apparatus according to any one of [1] to

[19] above, in which the beam pattern of the laser light is a top hat type." In this case, for example, in the fourth step, particles generated from the sample can be processed more uniformly.

[0027] A method of using a microscope apparatus according to the present disclosure may be

[21] "a method of using a microscope apparatus according to any one of items [1] to

[20] above, comprising: a first step of placing a sample in a chamber; a second step of evacuating the chamber to reduce the pressure inside the chamber; a third step of, after the first and second steps, performing ablation processing by irradiating the sample in the chamber with laser light through a transparent member that transmits the laser light to remove a portion of the sample; a fourth step of, after the first and second steps, irradiating the transparent member with the laser light while the sample is placed in the chamber to perform ablation processing of material attached to the transparent member to remove the material attached; and a fifth step of, after the third step, observing the sample using a microscope, wherein in the third step, a focal point of the laser light is positioned at a first position closer to the sample than the transparent member in the optical axis direction, and in the fourth step, the focal point is positioned at a second position closer to the transparent member than the sample in the optical axis direction."

[0028] In this method of using a microscope apparatus, a sample is placed in a chamber, the chamber is depressurized, and then ablation processing of the sample is performed by irradiating the sample with laser light through a transparent member. Therefore, particles generated during the ablation processing may adhere to the transparent member (or may be pre-adhered to the transparent member). In contrast, this method irradiates the transparent member with laser light to ablate the adhered material, thereby removing the adhered material from the transparent member. This makes it possible to suppress a decrease in the transmittance of the transparent member. Note that this method performs ablation processing when processing the sample and removing the adhered material. Therefore, compared to when thermal processing is performed with laser light during sample processing, damage to the sample during processing is suppressed, and even when laser light is irradiated onto the sample during the removal of the adhered material, damage to the sample is less likely to occur. Therefore, this method makes it possible to remove the adhered material from the transparent member while suppressing damage to the sample.

[0029] According to the present disclosure, it is possible to provide a method of using a microscope apparatus that can suppress a decrease in the transmittance of a transmitting member.

[0030] FIG. 1 is a schematic diagram showing a portion of a microscope apparatus according to this embodiment. FIG. 2 is a schematic diagram showing the remaining portion of the microscope apparatus shown in FIG. 1. FIG. 3 is a flowchart showing an example of a method of using the microscope apparatus according to this embodiment. FIG. 4 is a schematic diagram showing steps in the method of using the microscope apparatus shown in FIG. 3. FIG. 5 is a schematic diagram showing steps in the method of using the microscope apparatus shown in FIG. 3. FIG. 6 is a schematic diagram showing steps in the method of using the microscope apparatus shown in FIG. 3. FIG. 7 is a schematic diagram for explaining an example of dual-focal simultaneous processing. FIG. 8 is a schematic diagram showing a microscope apparatus according to a modified example. FIG. 9 is a flowchart showing each step when cleaning a transparent member according to the transmittance of the transparent member. FIG. 10 is a schematic diagram showing a microscope apparatus according to another modified example.

[0031] Hereinafter, a method of using a microscope apparatus according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description may be omitted.

[0032] Fig. 1 is a schematic diagram showing a part of a microscope apparatus according to this embodiment. Fig. 2 is a schematic diagram showing the remaining part of the microscope apparatus shown in Fig. 1. As will be described later, the microscope apparatus 1 shown in Fig. 1 and Fig. 2 includes a focused ion beam (FIB) apparatus that irradiates a sample with focused ions (e.g., Ga ions) to etch the sample, a scanning electron microscope (SEM) apparatus that irradiates the sample with an electron beam to observe the sample, and a laser apparatus that irradiates the sample with laser light to perform laser processing (here, ablation processing) of the sample, and is an apparatus that allows the SEM apparatus to observe a processed cross section of the sample formed by processing using the FIB apparatus and / or the laser apparatus.

[0033] The microscope device 1 includes a sample holder 2, a beam irradiation unit 3, a first microscope unit (microscope unit) 4, a second microscope unit (microscope unit) 5, a cover 7 (transmitting member), a chamber 10, and a laser device 20. A sample A is placed on the sample holder 2. The sample holder 2 may support the sample A without fixing it, as in the case where the sample A is simply placed on the sample holder 2, or may hold the sample A fixedly by, for example, gluing it on something. In this example, the sample holder 2 holds the sample A. The beam irradiation unit 3 is for irradiating the sample A held (placed (the same applies hereinafter)) on the sample holder 2 with a focused ion beam. Therefore, the beam irradiation unit 3 may include at least a focused ion beam emission unit of the FIB device.

[0034] The first microscope unit 4 is for observing the sample A held in the sample holder 2. More specifically, the first microscope unit 4 is configured to be able to obtain an image of the sample A (observe the sample A) by irradiating the sample A held in the sample holder 2 with an electron beam and detecting secondary electrons and the like generated in the sample A. Therefore, the first microscope unit 4 can be at least a part of the SEM apparatus that includes an electron beam emission unit and detection unit.

[0035] Like the first microscope unit 4, the second microscope unit 5 is used to observe the sample A held in the sample holder 2. More specifically, the second microscope unit 5 is capable of irradiating the sample A held in the sample holder 2 with an electron beam and detecting the electron beam scattered by the sample A, thereby acquiring information about the crystalline structure of the sample A (observing the sample A). That is, an example of the second microscope unit 5 may be a part of an SEM device using the electron backscatter diffraction (EBSD) method, including at least an electron beam emission unit and a detection unit. Note that the microscope device 1 may be equipped with a transmission electron microscope (TEM) device instead of (or in addition to) the SEM device. In this case, the first microscope unit 4 and the second microscope unit 5 may be at least a part of the TEM device.

[0036] The cover 7 is made of a material that transmits the laser light L described below, and is provided so as to cover the sample A held in the sample holder 2. As a result, the cover 7 can be placed at a reference position that is between the sample holder 2 and the beam irradiation unit 3, the first microscope unit 4, and the second microscope unit 5, and that is interposed in the optical path of the laser light L. The cover 7 is configured to be movable from the reference position so as not to be interposed between the sample holder 2 and the beam irradiation unit 3, the first microscope unit 4, and the second microscope unit 5.

[0037] The cover 7 may be formed in a box shape or a flat plate shape. If the cover 7 is box-shaped, it may be formed, for example, in a rectangular box shape with one side open, or in a box shape with one side open and a semicircular cross section (as shown in the example). In this case, the cover 7 may be arranged so that, with the sample A placed inside the box, the open part of the box faces the bottom of the chamber 10 and the bottom of the box faces the beam irradiation unit 3, the first microscope unit 4, and the second microscope unit 5. In this case, the edge forming the open part of the box may be in contact with the bottom of the chamber 10 or may be spaced apart from the bottom of the chamber 10 (as shown in the example).

[0038] The chamber 10 houses the sample holder 2, the beam irradiation unit 3, the first microscope unit 4, the second microscope unit 5, and the cover 7. The chamber 10 is formed with an entrance unit 11 for the laser light L, which is configured in the shape of a window and made of a material that transmits the laser light L. The chamber 10 also has an exhaust unit 12 for exhausting the inside of the chamber 10 to reduce the pressure (to create a vacuum). Furthermore, the chamber 10 may be provided with another unit 6 for processing or observing the sample A held in the sample holder 2.

[0039] The laser device 20 includes a laser output unit 30 and a laser optical system 40. The laser output unit 30 outputs ultrashort pulsed laser light L at a low fluence. The pulse width of the laser light L output from the laser output unit 30 is, for example, 1 ps or less. Furthermore, the low fluence of the laser light L may mean, for example, that the energy density of the laser light L is near a processing threshold of the sample A, which is determined so that ablation processing occurs during laser processing of the sample A. The laser optical system 40 irradiates the laser light L output from the laser output unit 30 onto the sample A held in the sample holder 2. The laser light L output from the laser output unit 30 is guided by the laser optical system 40 and incident into the chamber 10 from the incident unit 11.

[0040] The laser optical system 40 has a spatial light modulator 41 and a galvano scanner 43. The spatial light modulator 41 modulates the laser light output from the laser output unit 30 according to a modulation pattern and emits the modulated laser light. More specifically, the spatial light modulator 41 is, for example, an LCOS-SLM (Liquid Crystal On Silicon - Spatial Light Modulator), and displays a modulation pattern on a liquid crystal layer, thereby modulating the laser light L that enters and exits the liquid crystal layer according to the modulation pattern.

[0041] The spatial light modulator 41 can, for example, as described below, modulate the laser light L so that the laser light L has multiple focal points P in the optical axis direction B, or modulate the laser light L so as to correct aberrations that occur when the laser light passes through transparent members such as the cover 7 and the entrance portion 11, thereby suppressing the spread of the spot system at the focal position of the laser light L.

[0042] The galvano scanner 43 includes mirrors 43a and 43b, and by driving the mirrors 43a and 43b, the laser light L emitted from the spatial light modulator 41 is scanned and irradiated onto the sample A held by the sample holder 2. The laser light L emitted from the galvano scanner 43 is focused by a lens 42 toward the sample A. The lens 42 is, for example, an fθ lens.

[0043] The laser optical system 40 has a relay optical system 44. The relay optical system 44 is disposed between the spatial light modulator 41 and the galvanometer scanner 43. The relay optical system 44 includes a pair of lenses 44a and 44b, and is configured to transfer an image of the laser light L modulated by the spatial light modulator 41 onto the lens 42. The laser light L emitted from the spatial light modulator 41 and passed through the relay optical system 44 has its optical path adjusted by predetermined mirrors 56 and 57 and is then supplied to the galvanometer scanner 43.

[0044] The laser optical system 40 further includes a collimating lens 51, an output control unit (adjustment unit) 52, a beam diameter control unit (adjustment unit) 53, a half-wave plate 54, and a polarizing beam splitter 55, which are arranged in this order on the optical path of the laser light L traveling from the laser output unit 30 to the spatial light modulator 41. The collimating lens 51 collimates the laser light L output from the laser output unit 30 and emits it. Therefore, the collimated laser light L is incident on the spatial light modulator 41. The collimating lens 51 may be omitted.

[0045] The output control unit 52 is, for example, an attenuator, and adjusts the output of the laser light L output from the laser output unit 30. The beam diameter control unit 53 is, for example, a beam expander, and adjusts the beam diameter of the laser light L output from the laser output unit 30. In this way, the output control unit 52 and the beam diameter control unit 53 are disposed between the spatial light modulator 41 and the laser output unit 30, and function as adjustment units that adjust the output and beam diameter of the laser light L.

[0046] The half-wave plate 54 changes the polarization direction of the laser light L output from the laser output unit 30. The polarizing beam splitter 55 separates the laser light L, which is output from the laser output unit 30 and enters through the half-wave plate 54, into an s-polarized component and a p-polarized component. The p-polarized component (p-polarized laser light L) is incident on the spatial light modulator 41. As described above, the laser light L incident on the spatial light modulator 41 is modulated and then enters the chamber 10 via the galvano scanner 43, where it is used to scan the sample A.

[0047] The microscope device 1 described above can process the sample A using the focused ion beam from the beam irradiation unit 3 and the laser light L from the laser device 20. When the focused ion beam is used, the sample A can be processed and observed with high precision. On the other hand, when the laser light L is used, a large area of ​​the sample A can be processed and observed with high throughput.

[0048] Next, a method of using the microscope apparatus described above will be described. Fig. 3 is a flowchart showing an example of a method of using the microscope apparatus according to this embodiment. Figs. 4 and 5 are schematic diagrams showing steps in the method of using the microscope apparatus shown in Fig. 3. Note that in Figs. 4 and 5, the beam irradiation unit 3, first microscope unit 4, second microscope unit 5, and unit 6 of the microscope apparatus 1 shown in Fig. 1 are omitted from the illustration.

[0049] 3 and 4A, in the method of using the microscope apparatus 1 according to this embodiment, first, a sample A is placed in the chamber 10 (step S1, first step). In step S1, the sample A is held by the sample holder 2. Next, the chamber 10 is evacuated using the exhaust unit 12, thereby reducing the pressure inside the chamber 10 (creating a vacuum) (step S2, second step).

[0050] 3 and 4B, the sample A in the chamber 10 is irradiated with laser light L through the entrance portion 11 and the cover 7, which transmit the laser light L, to perform ablation processing and remove a portion of the sample A (step S3, third step). At this time, particles are generated from the sample A. In this step S3, the laser light L is scanned (irradiated) onto the sample A while the focal point P of the laser light L is positioned at a first position P1 on the sample A side relative to the cover 7 in the optical axis direction B of the laser light L. The first position P1 is, for example, the position where the laser light L is focused on the surface of the sample A on the cover 7 side.

[0051] As an example, in the method of using the microscope apparatus 1 according to this embodiment, the number of times that ablation processing of the sample A is performed in step S3 may be set in advance, and step S3 may be performed the number of times. Thermal processing is processing in which the temperature of the sample is increased by absorbing laser light into the sample, thereby melting the sample and removing a portion of the sample. In contrast, ablation processing is non-thermal processing in which the energy of the laser light L is used to cut bonds between molecules and atoms in the sample A, causing a portion of the sample A to instantaneously decompose and scatter in the area irradiated with the laser light L.

[0052] 3 and 5A, with the specimen A placed in the chamber 10, the cover 7 is irradiated with laser light L to perform ablation of the deposits, thereby removing the deposits from the cover 7 (cleaning the cover 7) (step S4, fourth step). In step S4, in addition to (or instead of) the ablation of the deposits on the cover 7, the laser light L is irradiated to particles (particles that may become deposits on the cover 7) generated from the specimen A during the ablation of the specimen A in step S3, thereby performing ablation of the particles. That is, in step S4, the laser light L is irradiated to ablate the particles generated from the specimen A. In step S4, the same laser light L as the laser light L used for ablation of the specimen A in step S3 is used. As described above, in the method of using the microscope apparatus 1 according to this embodiment, step S4 is performed after step S3.

[0053] The cover 7 includes a surface 7a on the sample A side and a surface 7b on the opposite side of the surface 7a (the side of the incident portion 11) from the surface 7a, which is the incident surface for the laser light L. As shown in FIG. 5B, in step S4, the focal point P of the laser light L is positioned at a second position P2 closer to the cover 7 than the sample A in the optical axis direction B, and the laser light L is scanned (irradiated) onto the surface 7a of the cover 7. Thus, in step S3, the distance between the first position P1, where the focal point P of the laser light L is positioned, and the sample A is shorter than the distance between the first position P1 and the cover 7, and the distance between the second position P2, where the focal point P of the laser light L is positioned, and the cover 7 in step S4 is shorter than the distance between the second position P2 and the sample A. In other words, the first position P1 is positioned closer to the sample A than the second position P2.

[0054] The second position P2 is a position within a predetermined distance D from the surface 7a of the cover 7 on the sample A side. The distance D is, for example, 2 mm. The second position P2 may be a position closer to the sample A than the surface 7a of the cover 7, or may be a position on the opposite side of the surface 7a of the cover 7 from the sample A. When the second position P2 is on the opposite side of the surface 7a of the cover 7 from the sample A, the second position P2 may be a position inside the cover 7 or a position outside the cover 7. By shifting the second position P2 (i.e., the focal point P) from the surface 7a along the optical axis direction B, the irradiation area of ​​the laser light L on the surface 7a can be widened. In particular, it is possible to adjust the amount of shift of the focal point P from the surface 7a along the optical axis direction B so as to expand the irradiation area of ​​the laser light L on the surface 7a while maintaining the energy density of the laser light L on the surface 7a at or above a threshold for removing deposits.

[0055] It should be noted that step S4 is performed in a state in which the specimen A is placed in the chamber 10. Therefore, in step S4, a portion of the laser light L irradiated onto the cover 7 may be transmitted through the cover 7 and irradiated onto the specimen A. Furthermore, as an example, in the method of using the microscope apparatus 1 according to this embodiment, the number of times that the ablation process of the deposits on the cover 7 (or the ablation process of the particles generated from the specimen A) in step S4 is performed may be set in advance, and step S4 may be performed the number of times.

[0056] As described above, in the method of using the microscope apparatus 1 according to this embodiment, the position of the focal point P of the laser light L is changed (switched) between the first position P1 and the second position P2 between steps S3 and S4. Various methods can be employed to switch the position of the focal point P of the laser light L.

[0057] For example, between steps S3 and S4, the position of the focal point P may be changed between a first position P1 and a second position P2 by driving a stage supporting the chamber 10 to move the chamber 10. Furthermore, between steps S3 and S4, the position of the focal point P may be changed between a first position P1 and a second position P2 by moving a lens 42 for focusing the laser light L toward the sample A or the cover 7.

[0058] Alternatively, between steps S3 and S4, the position of the focal point P may be changed between the first position P1 and the second position P2 using the galvano scanner 43. Furthermore, between steps S3 and S4, the position of the focal point P may be changed between the first position P1 and the second position P2 using the spatial light modulator 41. Furthermore, at least two of the above methods may be arbitrarily combined.

[0059] In the next step, it is determined whether the intended processing of the sample A has been completed (step S5). As an example, in step S5, the number of times to perform laser processing (e.g., the number of times step S3 is performed) is set in advance, and by determining whether the set number of laser processing operations has been completed, it is possible to determine whether the intended processing of the sample A has been completed. If the result of the determination in step S5 is that the intended processing of the sample A has not been completed (step S5: NO), steps S3 to S5 are performed again. On the other hand, if the result of the determination in step S5 is that the intended processing of the sample A has been completed (step S5: YES), as shown in FIG. 6 , the sample A is observed using the first microscope unit 4 or the second microscope unit 5 arranged in the chamber 10 (step S6, step S5).

[0060] In step S6, first, the cover 7 is moved from the reference position so that the cover 7 is not interposed between the sample A and the first microscope unit 4 or the second microscope unit 5. Thereafter, the sample A can be observed by irradiating the sample A with an electron beam E from the first microscope unit 4 or the second microscope unit 5 (the first microscope unit 4 in the illustrated example).

[0061] As described above, in the method of using the microscope apparatus 1 according to this embodiment, the sample A is placed in the chamber 10, the pressure inside the chamber 10 is reduced, and then the sample A is subjected to ablation processing by irradiating it with laser light L via the cover 7. Therefore, there is a risk that particles generated during the ablation processing may adhere to the cover 7 (or may have already adhered thereto).

[0062] In contrast, in the method of using the microscope apparatus 1 according to this embodiment, ablation processing of particles generated from the sample A is performed by irradiating the sample with laser light L. This prevents particles from adhering to the cover 7 and removes material adhering to the cover 7. This prevents a decrease in the transmittance of the cover 7. As a result, this method reduces the frequency of replacing the cover 7, enabling continuous processing. This makes it possible to remove a large volume of a single sample A or process multiple samples A without breaking the vacuum in the chamber 10. Note that this method performs ablation processing when processing the sample and particles generated from the sample. Therefore, compared to when thermal processing is performed using laser light L during processing of the sample A, damage to the sample A during processing is reduced, and even when the sample A is irradiated with laser light L during processing of particles generated from the sample A, damage to the sample A is less likely to occur. Therefore, this method prevents a decrease in the transmittance of the cover 7 while preventing damage to the sample A.

[0063] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the attachments on the cover 7 are removed by irradiating the cover 7 with laser light L to ablate the attachments. This makes it possible to suppress a decrease in the transmittance of the cover 7. Therefore, this method makes it possible to remove the attachments on the cover 7 while suppressing damage to the specimen A.

[0064] The wavelength of the laser light L used in the ablation processing of the sample A may be a wavelength that is absorbed by the sample A, or may be a wavelength that is not absorbed by the sample A. Even if the wavelength of the laser light L is a wavelength that is absorbed by the sample A, damage to the sample A is suppressed compared to thermal processing. Furthermore, if the wavelength of the laser light L is a wavelength that is not absorbed by the sample A, damage to the sample A is further suppressed.

[0065] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, step S4 is performed after step S3, so that deposits that have been generated in the preceding step S3 and that have adhered to the cover 7 (or particles generated from the specimen A) can be removed in the subsequent step S4.

[0066] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the position of the focal point P may be changed between the first position P1 and the second position P2 by moving the chamber 10 between steps S3 and S4. In this case, by moving the chamber 10, the position of the focal point P of the laser light L can be changed between the first position P1 in step S3 and the second position P2 in step S4.

[0067] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, between steps S3 and S4, the position of the focal point P may be changed between a first position P1 and a second position P2 by moving the lens 42 for focusing the laser light L toward the sample A or the cover 7. In this case, by moving the lens 42, it is possible to change the position of the focal point P of the laser light L between the first position P1 in step S3 and the second position P2 in step S4.

[0068] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, between steps S3 and S4, the position of the focal point P may be changed between a first position P1 and a second position P2 using the galvano scanner 43. In this case, by using the galvano scanner 43, it is possible to change the position of the focal point P of the laser light L between the first position P1 in step S3 and the second position P2 in step S4.

[0069] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, between steps S3 and S4, the position of the focal point P may be changed between a first position P1 and a second position P2 using the spatial light modulator 41. In this case, by using the spatial light modulator 41, it is possible to change the position of the focal point P of the laser light L between the first position P1 in step S3 and the second position P2 in step S4.

[0070] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the pulse width of the laser light L is 1 ps or less, which makes it possible to effectively perform ablation processing.

[0071] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the second position P2 may be a position within 2 mm from the surface 7 a on the specimen A side of the cover 7. In this way, by setting the position (second position P2) of the focal point P of the laser light L in step S4 within 2 mm from the surface 7 a on the specimen A side of the cover 7, it is possible to ensure laser intensity sufficient to remove any deposits on the surface 7 a of the cover 7.

[0072] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the second position P2 may be a position on the opposite side of the surface 7a of the cover 7 on the side of the sample A. In this way, by moving the position of the focal point P of the laser light L (second position P2) in step S4 further away from the sample A, damage to the sample A can be suppressed.

[0073] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the second position P2 may be a position inside the cover 7. In this way, the position of the focal point P of the laser light L in step S4 (second position P2) may be set inside the cover 7.

[0074] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, the second position P2 may be a position outside the cover 7. In this way, by setting the position (second position P2) of the focal point P of the laser light L in step S4 outside the cover 7 on the side opposite to the specimen A, it is possible to ensure a wider irradiation area of ​​the laser light L on the surface 7 a of the cover 7 on the specimen A side.

[0075] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, in step S4, the laser light L that has passed through the cover 7 may be irradiated onto the specimen A. As described above, in this method, the same laser light L as the laser light L used for ablation processing of the specimen A is used to process particles generated from the specimen A. Therefore, even if part of the laser light L irradiated onto the cover 7 in step S4 is irradiated onto the specimen A, damage to the specimen A is unlikely to occur. Therefore, in step S4, it is not necessary to move the specimen A or block the laser light L so that part of the laser light L is not irradiated onto the specimen A.

[0076] Furthermore, in the method of using the microscope apparatus 1 according to this embodiment, steps S4 and S6 are performed in the same chamber 10. In this way, the observation of the sample A in step S5 may be performed in the same chamber 10 as the chamber in which the ablation processing of particles generated from the sample A in step S4 is performed. In this case, it is not necessary to move the sample A between steps S4 and S6, and high-precision processing and observation become possible.

[0077] The above embodiment has described one aspect of the method of using the microscope apparatus according to the present invention. Therefore, the method of using the microscope apparatus according to the present invention is not limited to the method of using the microscope apparatus 1 described above, and can be modified as desired. Next, modified examples will be described.

[0078] In the above embodiment, an example in which step S4 is performed after step S3 has been described, but the order of steps S3 and S4 is not limited to this. For example, if the microscope device 1 has already been used, there may be a deposit already attached to the cover 7. Therefore, step S4 may be performed before step S3 is performed.

[0079] Alternatively, step S3 may be performed again after step S3 and step S4 are performed in this order. In this case, the deposits removed from the cover 7 in step S4 and attached to the specimen A can be removed by performing step S3 again.

[0080] Furthermore, steps S3 and S4 may be performed simultaneously. In this case, the focal point P of the laser light L is formed at both the first position P1 and the second position P2. For this purpose, as an example, as shown in FIG. 7 , the laser light L can be modulated by the spatial light modulator 41 so that the focal point P of the laser light L is formed at each of the first position P1 and the second position P2 at overlapping positions along the optical axis direction B (two-focal simultaneous processing). That is, by modulating the laser light L with the spatial light modulator 41 to form the focal point P at both the first position P1 and the second position P2, steps S3 and S4 can be performed simultaneously. Note that, when performing two-focal simultaneous processing, the laser light L may be modulated by the spatial light modulator 41 so that the focal points P of the laser light L are formed at each of the first position P1 and the second position P2 so as not to overlap each other in the optical axis direction B (i.e., by being shifted from each other in a plane direction intersecting the optical axis direction B).

[0081] As another example, steps S3 and S4 may be performed simultaneously by using an optical element having a light branching function to branch the laser beam L into two branched beams and focusing each of the two branched beams to form a focal point P at the first position P1 and the second position P2, respectively. In this case as well, the focal points P at the first position P1 and the second position P2 may or may not overlap with each other along the optical axis direction B.

[0082] As yet another example, steps S3 and S4 may be performed simultaneously by outputting two laser beams L from the laser output unit 30 and focusing each of the two laser beams L to form a focal point P at the first position P1 and the second position P2, respectively. In this case, too, the focal points P at the first position P1 and the second position P2 may or may not overlap with each other along the optical axis direction B. As described above, by simultaneously performing steps S3 and S4, sample A and particles generated from sample A can be processed simultaneously, thereby shortening the processing time.

[0083] In the above embodiment, the cover 7 is exemplified as a transparent member for the laser light L that is the target for cleaning of deposits. However, if the microscope device 1 does not have the cover 7, or if the microscope device 1 has the cover 7 but deposits may also adhere to the incident part 11 of the chamber 10, the transparent member that is the target for cleaning may be the incident part 11 (and the cover 7).

[0084] Furthermore, in the above embodiment, an example has been given of a case where all processing and observation, including steps S3, S4, and S6, are performed in the same chamber 10. However, steps S3, S4, and S6 may be performed in different chambers. In this way, the observation of sample A in step S6 may be performed in a chamber different from the chamber 10 in which the ablation processing in steps S3 and S4 is performed. In this case, adhesion of particles generated during the ablation processing to the first microscope unit 4 and the second microscope unit 5 is suppressed, and a decrease in the accuracy of the observation of sample A is suppressed.

[0085] The beam pattern of the laser light L may be a top hat type. In this case, for example, in step S4, it is possible to more uniformly process particles generated from the sample A. In addition, in this case, it is possible to process a wider range compared to when the laser light L having a Gaussian distribution is used.

[0086] Furthermore, in the above embodiment, an example has been given of a case in which the ablation processing of the specimen A in step S3 is performed a preset number of times, and then the cleaning of the transparent member (cover 7 in the above embodiment) in step S4 (ablation processing of particles generated from the specimen A) is performed. This method makes it possible to efficiently remove deposits that accumulate on the transparent member as step S3 is performed multiple times, and effectively maintain the transmittance of the transparent member. On the other hand, it is also possible to measure the transmittance of the transparent member after performing step S3, and then perform step S4 to clean the transparent member based on the measurement results.

[0087] In this case, as shown in Fig. 8, the microscope apparatus 1 can be provided with a configuration for measuring the transmittance of the transparent member. Note that the beam irradiation unit 3, the first microscope unit 4, the second microscope unit 5, and the unit 6 are not shown in Fig. 8. Also, Fig. 8 illustrates the incident unit 11 of the chamber 10 as an example of the transparent member to be cleaned.

[0088] 8 , the microscope device 1 includes a laser output unit 60, a dichroic mirror 61, a beam splitter 62, a mirror 63, and a detector 64. The laser light L output from the laser output unit 30 passes through, for example, the above-mentioned laser optical system 40 (not shown), is reflected by a mirror 57, and enters a lens 58 via the dichroic mirror 61, and is focused toward the sample A or the entrance unit 11.

[0089] The laser output unit 60 outputs a measurement laser beam L0 having a wavelength different from the processing laser beam L output from the laser output unit 30. The laser beam L0 output from the laser output unit 60 is incident on a dichroic mirror 61 via a beam splitter 62, reflected therefrom, and focused toward the incident unit 11 by a lens 58. A portion of the laser beam L0 incident on the incident unit 11 is reflected by the surface 11a of the incident unit 11 on the sample A side. The reflected light of the laser beam L0 is guided via the lens 58, the dichroic mirror 61, the beam splitter 62, and the mirror 63, and is incident on and detected by a detector 64. This allows the transmittance of the incident unit 11 to be measured.

[0090] 9 is a flowchart showing the steps of cleaning the transparent member (incident portion 11) in accordance with its transmittance. As shown in FIG. 9, steps S1, S2, and S3 are performed in this example, similar to the above-described embodiment. Thereafter, the transmittance of the incident portion 11 is measured using the configuration shown in FIG. 8, and it is determined whether the measured transmittance has decreased to or above a predetermined threshold (step S14).

[0091] If the determination result of step S14 shows that the transmittance of the incident portion 11 has not decreased to a predetermined threshold or more (step S14: NO), step S6 (observation of sample A) is performed as in the above embodiment. On the other hand, if the determination result of step S14 shows that the transmittance of the incident portion 11 has decreased to a predetermined threshold or more (step S14: YES), cleaning of the incident portion 11 is performed as in the above embodiment (step S4). That is, by irradiating the incident portion 11 with laser light L, ablation processing of deposits on the surface of the incident portion 11 facing the sample A is performed, and the deposits are removed.

[0092] After the determination in step S14 and before performing step S6, it is possible to determine whether the intended processing of sample A has been completed, similar to step S5 described above. In this case, the number of times laser processing is performed (for example, the number of times step S3 is performed) is set in advance, and it is possible to determine whether the intended processing of sample A has been completed by determining whether the set number of times laser processing has been completed. Then, if the result of this determination is that the intended processing of sample A has been completed, it is possible to observe sample A in step S6 as described above.

[0093] As described above, by cleaning the incident part 11 based on the transmittance of the incident part 11, it is possible to efficiently clean the incident part 11 a necessary and sufficient number of times.

[0094] The configuration for measuring the transmittance of the incident part 11 is not limited to the example in FIG. 8 , and may be, for example, the configuration shown in FIG. 10 . In the example in FIG. 10 , the microscope device 1 includes a laser output unit 60, a beam splitter 62, a mirror 63, a detector 64, a dichroic mirror 65, and a galvanometer scanner 70. The dichroic mirror 65 and the galvanometer scanner 70 are arranged in this order on the optical path of the laser light L. As a result, the laser light L output from the laser output unit 30 passes through, for example, the laser optical system 40 (not shown) and the dichroic mirror 65, is reflected by the galvanometer scanner 70, enters the lens 58, and is focused toward the sample A or the incident part 11.

[0095] The laser light L0 output from the laser output unit 60 enters the dichroic mirror 65 via the beam splitter 62, is reflected by the dichroic mirror 65 and the galvanometer scanner 70 in order, and is focused by the lens 58 toward the incident unit 11. A portion of the laser light L0 entering the incident unit 11 is reflected by the surface 11a of the incident unit 11 on the sample A side. The reflected light of the laser light L0 is guided via the lens 58, the galvanometer scanner 70, the dichroic mirror 65, the beam splitter 62, and the mirror 63, and enters the detector 64 where it is detected. This measures the transmittance of the incident unit 11. Note that in the configuration shown in FIG. 10 , a reflective spatial light modulator 80 may be provided instead of the galvanometer scanner 70.

[0096] The beam irradiation unit 3 is not essential to the microscope apparatus 1 and may be omitted. The microscope apparatus 1 may also include a cooling unit for cooling the spatial light modulator 41. In this case, the thermal influence on the spatial light modulator 41 is suppressed.

[0097] Furthermore, in the microscope device 1, the laser optical system 40 has the collimating lens 51 for making the collimated laser light L incident on the spatial light modulator 41. However, when collimated light is output from the laser output unit 30, the collimating lens 51 may be omitted.

[0098] In addition, the microscope device 1 may omit one of the first microscope unit 4 and the second microscope unit 5, and may include at least one microscope unit. Furthermore, in the microscope device 1, it is also possible to omit one or both of the output control unit 52 and the beam diameter control unit 53, and the relay optical system 44.

[0099] Furthermore, in the above embodiment, an example has been given of the case where the sample A is observed in step S6 using the first microscope unit 4 or the second microscope unit 5 arranged in the chamber 10. However, in step S6, the observation is not limited to the first microscope unit 4 or the second microscope unit 5 arranged in the chamber 10, and the sample A may also be observed using a microscope unit arranged outside the chamber 10. In this case, at least one of the first microscope unit 4 and the second microscope unit 5 may be arranged outside the chamber 10 (for example, in a chamber other than the chamber 10) and used for the observation in step S6.

[0100] 1...microscope device, 4...first microscope section (microscope section), 5...second microscope section (microscope section), 7...cover (transparent member), 10...chamber, 11...incident section (transparent member), 41...spatial light modulator, 42...lens, 43...galvanometer scanner.

Claims

1. A first step of placing a sample in a chamber; a second step of reducing the pressure inside the chamber by evacuating the chamber; a third step of, after the first step and the second step, performing ablation processing by irradiating the sample in the chamber with the laser light through a transparent member that transmits the laser light, thereby removing a portion of the sample; a fourth step of, after the first step and the second step, irradiating the laser light with the sample placed in the chamber to perform ablation processing of particles generated from the sample; a fifth step of observing the sample using a microscope unit after the third step; Equipped with In the third step, a focal point of the laser light is positioned at a first position closer to the sample than the transparent member in the optical axis direction of the laser light, In the fourth step, the focusing point is positioned at a second position closer to the transmitting member than the sample in the optical axis direction. How to use microscope equipment.

2. The fourth step is carried out after the third step. A method for using the microscope apparatus according to claim 1.

3. After the fourth step, the third step is carried out again. A method for using the microscope apparatus according to claim 2.

4. Between the third step and the fourth step, the chamber is moved to change the position of the light focusing point between the first position and the second position. A method for using the microscope apparatus according to claim 1.

5. Between the third step and the fourth step, a lens for focusing the laser light toward the sample or the transparent member is moved, thereby changing the position of the focusing point between the first position and the second position. A method for using the microscope apparatus according to claim 1.

6. Between the third step and the fourth step, a position of the light-focusing point is changed between the first position and the second position using a galvano scanner. A method for using the microscope apparatus according to claim 1.

7. Between the third step and the fourth step, a spatial light modulator is used to change the position of the light-focusing point between the first position and the second position. A method for using the microscope apparatus according to claim 1.

8. The fourth step is carried out simultaneously with the third step. A method for using the microscope apparatus according to claim 1.

9. modulating the laser light by a spatial light modulator to form the focusing points at both the first position and the second position, thereby simultaneously performing the third step and the fourth step; A method for using the microscope apparatus according to claim 8.

10. The pulse width of the laser light is 1 ps or less. A method for using the microscope apparatus according to claim 1.

11. the second position is a position within 2 mm from the surface of the transmitting member on the sample side; A method for using the microscope apparatus according to claim 1.

12. the second position is a position on the opposite side of the sample from the surface of the transmitting member facing the sample; A method for using the microscope apparatus according to claim 1.

13. the second position is a position inside the transparent member; A method for using the microscope apparatus according to claim 12.

14. the second position is a position outside the transparent member; A method for using the microscope apparatus according to claim 12.

15. In the fourth step, the laser light transmitted through the transmitting member is irradiated onto the sample. A method for using the microscope apparatus according to claim 1.

16. the transparent member is an incident portion of the laser light in the chamber; A method for using the microscope apparatus according to claim 1.

17. the transparent member is a cover provided to cover the sample in the chamber; A method for using the microscope apparatus according to claim 1.

18. The fourth step and the fifth step are performed in different chambers. A method for using the microscope apparatus according to claim 1.

19. The fourth step and the fifth step are performed in the same chamber. A method for using the microscope apparatus according to claim 1.

20. the beam pattern of the laser light is a top hat type; A method for using the microscope apparatus according to claim 1.

21. In the fourth step, the laser light is irradiated onto the transparent member to perform ablation processing of the deposits on the transparent member, thereby removing the deposits. A method for using the microscope apparatus according to any one of claims 1 to 20.