Charged particle beam device, sample observation method, sample platform, observation system, and light emitting member

The purpose of the present invention is to eliminate the effort in placement and extraction of samples in observations using transmitted charged particles. A charged particle beam device (601) is characterized by having: a charged particle optical lens tube that irradiates a sample (6) with a primary charged particle beam; a sample stage on which a light emitting member (500) that emits light because of charged particles that have come by transmission internally in the sample (6) or scattering therefrom or a sample platform (600) having the light emitting member (500) is attachably and detachably disposed; and a detector (503) that detects the light emitted by the light emitting member.

TECHNICAL FIELD

The present invention relates to a charged particle beam apparatus that makes it possible to observe the inside of a sample and a sample support thereof.

BACKGROUND ART

In order to observe an inner structure in a minute region of a substance, a scanning transmission electron microscope (STEM), a transmission electron microscope (TEM), or the like is used. As a typical observation method of observing the inside of a sample by using such an electron microscope, a method has been known in which a sample that is sliced into such a thickness that an electron beam can be transmitted therethrough is arranged on a meshed sample support with multiple pores and the transmitted electron beam is obtained by a detector that is arranged on a side opposite to an electron source side with respect to a sample surface. However, since the method employs a configuration in which the sample floats over pores of the mesh, it is significantly difficult to perform an operation of mounting the sample on the sample support. Thus, PTL 1 proposes an electron detector on which a sample to be observed is directly placed.

In addition, a minute region of a substance can also be observed by an optical microscope as well as the electron microscope. By using the optical microscope, it is possible to obtain color information that cannot be obtained by the electron microscope in principle. According to the optical microscope, it is possible to obtain a transmission optical image by irradiating a sample with white light or specific light and forming an image from light which is absorbed by or emitted from the sample and has color information. In doing so, it is possible to dye only a specific region in a sample, such as biological cells, by applying a specific coloring material to the cells and to thereby observe which region has been dyed or has not been dyed by observing the color. This method has been widely used in the fields of pathologic diagnosis and life sciences, in particular.

While the electron microscope cannot obtain color information, the electron microscope can observe a minute region, which cannot be observed by the optical microscope, with high resolution. In addition, information that can be obtained from an image of the electron microscope is information reflecting differences in density of the sample and is different from information that can be obtained by the optical microscope.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

According to a sample support that also functions as a detector as disclosed in PTL 1, a sample is arranged directly on an electrical system wired to a semiconductor, a metal film, or the like with electric wiring or the like. Since the wiring is connected to the sample support that also functions as a detector, significant time and effort are required to disconnect the electric wiring in order to observe the same sample with another apparatus. In a case of observing cultured cells which require culturing of the sample itself on the sample support for observation with the microscope, for example, a circuit with the electric wiring connected thereto is dipped into a culture solution or the like, and it becomes difficult to place the circuit on the sample that also functions as a detector, in some cases. As described above, installation and extraction of a sample for observation by the transmission charged particle requires significant time and effort in the related art.

The present invention was made in view of such problems, and an object thereof is to provide a charged particle beam apparatus, a sample observation method, a sample support, an observation system, and a light-emitting member that make it possible to simply observe an image by a transmission charged particle.

Solution to Problem

In order to solve the aforementioned problem, the present invention is configured to generate a transmission charged particle image of a sample by detecting light that is caused by charged particles which have been transmitted through or scattered in the sample being incident on a light-emitting member on which the sample as a target of the irradiation of a charged particle beam is arranged directly or via a predetermined member.

Advantageous Effects of Invention

According to the present invention, it is possible to simply observe an image by a transmission charged particle by causing a sample support with a sample placed thereon to emit light and detecting the emitted light.

Problems, configurations, and advantages other than those described above will be clarified by the following descriptions of the embodiments.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the respective embodiments will be described with reference to drawings.

A detailed description of a sample support according to the present invention and a description of a charged particle beam apparatus to which the sample support is applied will be given below. However, this is only an example of the present invention, and the present invention is not limited to the embodiment described below. The present invention can be applied to an apparatus for observing a sample by irradiation with a charged particle beam, such as a scanning electron microscope, a scanning ion microscope, or a scanning transmission electron microscope, a composite apparatus of such an apparatus and a sample processing apparatus, and an analysis and inspection apparatus as an application thereof. The sample support according to the present invention and the charged particle beam apparatus on which the sample support is placed configure an observation system that makes it possible to observe a transmission charged particle beam image.

In the specification, “atmospheric pressure” is an air atmosphere or a predetermined gas atmosphere and means a pressure environment at atmospheric pressure or a slightly negative pressure. Specifically, the atmospheric pressure ranges from about 105Pa (atmospheric pressure) to about 103Pa.

In the specification, a “sample support” means a unit that can be detached from the charged particle beam apparatus along with a sample in a state in which the sample is placed thereon. Specifically, the “sample support” unit may include a light-emitting member and a base or may be formed only of the light-emitting member as will be described later.

First Embodiment

Outline

First, a description will be given of an outline of the embodiment. In the embodiment, a charged particle microscope and an observation system that generate a transmission charged particle beam image by transforming a charged particle beam transmitted through or scattered in a sample into light and detecting the light will be described. More specifically, at least a part of a sample support on which a sample is placed is formed of a light-emitting member that emits light in response to irradiation with a charged particle beam, light is generated by irradiation of the light-emitting member with the charged particle beam that is transmitted through or is scattered in the sample placed on the light-emitting member, and a transmission charged particle beam image is generated by detecting the light with a detector provided in the charged particle microscope. That is, in the embodiment, the charged particle beam that is transmitted through the sample is not directly detected but is transformed into light and the light is then detected. As will be described in detail later, the light-emitting member that transforms the charged particle beam into light does not require wiring, such as a power cable and a signal line, connected from the outside. For this reason, it is possible to observe a sample with the charged particle beam microscope and another apparatus by using the same sample support, and significant time and effort are not required for disconnecting the electric wiring when the sample is moved between the apparatuses. In addition, it is possible to simply attach and detach the light-emitting member itself or the sample support including the light-emitting member to and from the apparatuses and to thereby easily set any sample on the sample support. This is significantly effective in a case of observing cultured cells, which require culturing the sample itself on the sample support for observation with the microscope, in particular.

Furthermore, it is possible to perform observation with the charged particle beam microscope and observation with another apparatus such as an optical microscope if the sample support according to the embodiment is used as illustrated inFIG. 1. FIG.1illustrates a sample support600according to the embodiment that is provided with a detection element500(also referred to as a light-emitting member) capable of emitting light by transforming or amplifying the charged particle beam into light, a charged particle beam microscope601, and an optical microscope602. A sample6can be mounted to the sample support600.

In the embodiment, the detection element that is provided with the sample support is preferably made of a transparent member. Hereinafter, “transparent” in the specification means that visible light, ultraviolet light, or infrared light in a specific wavelength region can be transmitted, or that visible light, ultraviolet light, or infrared light in the entire wavelength region can be transmitted. The ultraviolet light is light in a wavelength region from about 10 nm to about 400 nm, the visible light is light in a wavelength region from about 380 nm to about 750 nm, and the infrared light is light in a wavelength region from about 700 nm to about 1 mm (=1000 μm). For example, it is considered that visible light in the specific wavelength region can be transmitted in a case of a see-through material even if a color is slightly mixed, and that visible light in the entire wavelength region can be transmitted in a case of a colorless transparent material. Here, “can be transmitted” means that a sufficient amount of light for observation with the optical microscope is transmitted by at least the light in the wavelength region (the transmittance is preferably equal to or greater than 50%, for example). In addition, the specific wavelength region described herein is a wavelength region including at least a wavelength region that is used for the observation with the optical microscope. Therefore, it is possible to use the wavelength region for a typical optical microscope (transmission optical microscope) that is capable of detecting a “light transmission signal”, which is obtained in response to light being transmitted through a sample from one surface side of the sample support according to the embodiment, from the other surface side of the sample support. Any optical microscope can be employed as long as the microscope employs light, such as a biological microscope, a stereoscopic microscope, an inverted microscope, a metallurgical microscope, a fluorescence microscope, or a laser microscope. Although a “microscope” is exemplified for illustrative purposes, the present invention is generally applicable to apparatuses that obtain information by irradiating a sample with light regardless of a magnifying power of an image.

According to the embodiment, it is possible to obtain a transmission charged particle microscope image by irradiating the sample6with a charged particle beam that is generated in the charged particle beam microscope and then detecting a “charged particle transmission signal” that is transmitted through or scattered in the sample by a detection element that is provided in the sample support. As will be described later, an optical detector503is provided in the charged particle beam microscope601in order to transform or amplify the light from the detection element500into an electrical signal.

Since information obtained by an electron microscope and information obtained by an optical microscope are different, there have been more requirements for observing the same sample by both the electron microscope and the optical microscope. However, light cannot be transmitted through the sample support that also functions as a detector as disclosed in PTL 1, for example, and the sample support is for the electron microscope and does not allow observation by the optical microscope in practice. For this reason, it is necessary to separately produce a sample for the electron microscope and a sample for the optical microscope, and there is a problem in that creation of the samples requires time and effort.

Since the sample support according to the embodiment can be mounted to a charged particle beam microscope apparatus such as an electron microscope, the sample support can be a common sample support that can be commonly used for both the electron microscope and the optical microscope. That is, it is possible to perform charged particle beam observation and optical observation while a sample is arranged on one sample support by moving the same sample supports between the respective microscopes as illustrated by the arrow in the drawing and observing the sample without producing a plurality of samples for the observation with both the microscopes or moving the sample therebetween. In addition, the same sample support may be mounted to the respective microscopes that are individually arranged as illustrated inFIG. 1, or a composite microscope apparatus in which an optical microscope and a charged particle microscope are integrated may be used as will be described later. Hereinafter, a detailed description will be given of the sample support, a sample installation method, an image acquisition principle, an apparatus configuration, and the like.

<Description of Sample Support>

A detailed description will be given of the sample support according to the embodiment with reference toFIG. 2. The sample support according to the embodiment is configured of the detection element500that transforms a charged particle beam into light and a base501(also referred to as a transparent member when the base501is transparent) that supports the detection element500. When observation with the optical microscope and observation with the charged particle microscope are performed by using the same sample support, it is preferable that the detection element500and the base501are transparent. The sample6is mounted directly on the detection element500. Alternatively, the sample6may be mounted indirectly via a member such as a film as will be described later. Although the base501is ideally colorless and transparent, a slight color may be mixed. As the base501, a transparent glass, a transparent plastic, a transparent crystal substance, or the like is used. In a case in which it is desired to perform observation with a fluorescence microscope or the like, plastic is preferably used since it is better that fluorescent light is not absorbed. According to the sample support of the embodiment, it is possible to perform optical observation with a microscope as long as at least the detection element and the base501that are between a location where the sample is arranged and a surface that faces the location, at which the sample is arranged, on the sample support are “transparent”. Moreover, the base501is not necessarily provided as will be described later.

The detection element500is an element that detects a charged particle beam that flies with energy from about several keV to about several tens of keV, for example, and emits light, such as visible light, ultraviolet light, or infrared light, when being irradiated with the charged particle beam. In a case of being used in the sample support according to the embodiment, the detection element transforms a charged particle, which is transmitted through or scattered in the sample placed on the sample support, into light. As the detection element, a scintillator, a luminescent light-emitting material, a YGA (yttrium, aluminum, garnet) element, a YAP (yttrium, aluminum, perovskite) element, and the like are exemplified. As the light-emitting wavelength, a specific or arbitrary wavelength region among those of visible light, ultraviolet light, and infrared light may be used. Examples of the scintillator include an inorganic scintillator made of an inorganic material such as SiN, a plastic scintillator or an organic scintillator that is contained in a material capable of emitting light such as polyethylene terephthalate, and a material coated with a liquid scintillator contained in anthracene or the like. The detection element500may be made of any material as long as the element can transfer the charged particle beam into light. In addition, the detection element is not limited to an attachable and detachable solid, and may be a thin film or a fine particle coated with a fluorescent agent that emits fluorescent light in response to irradiation with the charged particle beam. In the embodiment, members that emit light in response to reception of the charged particles by light-receiving surfaces, which include the aforementioned examples, will be collectively referred to as light-emitting members. A mean free path in solid of the charged particle beam depends on an acceleration voltage of the charged particle beam and ranges from several tens of nm to several tens of μm. Therefore, the light-emitting region in the upper surface of the detection element500is a region with the same thickness from the surface of the detection element. Accordingly, it is only necessary that the thickness of the detection element500exceeds the thickness. In contrast, in a case in which performing observation with the optical microscope using the same sample support is taken into consideration, it is necessary that the light transmission signal during the observation with the optical microscope can be transmitted as much as possible. Therefore, it is preferable that the thickness of the detection element is as thin as possible if a slight color is mixed therein.

In addition, the detection element500may be a thin film or a fine particle coated with a fluorescent agent that emits fluorescent light in response to irradiation with the charged particle beam. As a fabrication method, it is possible to employ a method of dissolving the fluorescent agent in a solvent such as water or alcohol and spin-coating or dip-coating a prepared slide with the mixture. Alternatively, the mixture may be sprayed to coat the prepared slide.

As sample supports that are used often with the optical microscope, there are transparent sample supports such as a slide glass (or a prepared slide) and a dish (or a petri dish). That is, if a sample support provided with the detection element, which is capable of transforming the charged particle beam into light, according to the embodiment is formed into a shape of a typical slide glass (for example, about 25 mm×about 75 mm×about 1.2 mm) dedicated for the optical microscope, it is possible to mount and observe a sample in the same manner as that in which a user previously experienced or felt during usage. Therefore, it is possible to use the sample support for primary screening with the optical microscope and for detailed observation of a selected sample with the charged particle microscope. Alternatively, it is possible to perform observation by using the sample support according to the embodiment as screening prior to observation with a high-performance transmission charged particle beam microscope since preparation of a sample by a typical high-performance transmission charged particle beam microscope device requires significant effort. In addition, a slide glass case and a sample mounting device for the optical microscope, which are owned by a user of the optical microscope, can be utilized. AlthoughFIG. 2illustrates a sectional shape of a slide glass, a dish (or petri dish) shape as illustrated inFIG. 3may be employed.FIG. 3(a)is a sectional view, andFIG. 3(b)is an arrow view. Since a side wall504is provided at a circumferential edge at a portion where a sample is to be arranged as compared withFIG. 2, the sample such as liquid does not leak.

FIGS. 2 and 3illustrate a state where the position of the upper surface of the detection element500coincides with the position of the upper surface of the base501. In order to make it possible to cause the user of the optical microscope to mount the sample in the same manner as that in which the user previously felt and experienced when using a slide glass or a petri dish, it is desirable that the upper surface (that is, the location on which the sample is arranged) of the detection element500is made to coincide with the upper surface of the base501at the same height such that not much unevenness is present between the detection element500and the base501.FIG. 4illustrates an example of the sample support in which the upper surface of the detection element500coincides with the upper surface of the base501. As a fabrication method, it is only necessary to separately produce the detection element500and the base501, providing a concave portion to a transparent member, such as glass or plastic, for the base501, and fitting the detection element500thereinto. If one of the detection element500and the base501projects from the other, optical plane grinding by polishing or the like may be performed. The base501and the detection element500are fixed to each other with an adhesive, a double-stick tape, a mechanical fitting, or the like. Alternatively, the base501and the detection element500may be bonded to each other by chemical bonding. Alternatively, optical grinding may be performed until the detection element is exposed to the surface of the sample support after producing the detection element500and the base501while fitting the detection element500thereinto from the beginning.

If it is possible to use a significantly large detection element, the entire surface of the sample support may be configured as the detection element as illustrated inFIG. 5(a). That is, the detection element itself may be used as the sample support, or alternatively, the entire region on the side of the surface, on which the sample is placed, of the transparent member may be used as the light-emitting member. In such a case, it is possible to obtain a transmission signal of the charged particle beam at any positions on the sample support. According to another configuration, a plurality of detection elements may be arranged on a transparent member as illustrated inFIG. 5(b). In a case in which there are a plurality of samples, this configuration makes it possible to easily recognize which sample is present at which detection element position.

Since the mean free path in solid of the charged particle beam ranges from several tens of nm to several tens of μm while depending on the acceleration voltage of the charged particle beam as described above, a film502that is sufficiently thinner than the mean free path may be arranged between the detection element500and the sample. That is, the sample is placed on the thin film502that covers the detection element500. The sample support will be shown inFIG. 6(a). The thickness is illustrated as A in the drawing. It is necessary that the thin film502is transparent with respect to the charged particle beam. That is, it is necessary to select a thickness and a material that allow at least a part of the charged particle beam to be transmitted. In a case of the observation with the optical microscope, it is further necessary that the thin film502is transparent to light. By arranging such a thin film502, it is possible to prevent the surface of the detection element500from being contaminated or scratched, for example. However, if the thin film502is an insulating substance, there is a possibility of electrification during irradiation of the detection element500with the charged particle beam in vacuum and it becomes difficult to observe the sample. Therefore, the thin film502inFIG. 6(a)is made of a conductive member such that it is possible to remove the electrification. In addition, the thin film502and the base501may be integrally formed into a same member as illustrated inFIG. 6(b). That is, it is possible to produce the sample support inFIG. 6(b)by producing the base501and the detection element500while fitting the detection element500into the base501and performing optical grinding until the distance between the upper surface of the detection element500and the base501becomes A. This results in prevention of the surface of the detection element500from being contaminated or scratched, for example, at low cost since less types of members are used as compared with the sample support inFIG. 6(a). Although not shown in the drawing, the portion represented as A in the drawing may include an uneven shape, for example. In such a case, it is possible to arrange a space of a predetermined distance, namely a gas material of a predetermined type and pressure between the mounted sample and the detection element500. As described above, a predetermined member in the form of solid, liquid, or gas may be arranged between the light-emitting member and the sample, and the sample may be arranged on the light-emitting member via the predetermined member.

In a case of using a slide glass (or a prepared slide) or a dish (or a petri dish) that is used often with the optical microscope, the sample support is coated with a material for enhancing adhesiveness between the sample and the sample support in order for the sample not to be separate from the sample support in some cases. In a case in which the sample is a biological sample such as cells, for example, the surface of the cells is in a negatively charged state due to a phospholipid bilayer. Therefore, peeling-off of the cell sample from the sample support is prevented by coating the sample support such as a slide glass with a molecule (lysine, aminosilane, or the like) in a positively charged state in some cases. For this reason, the molecule in the positively charged state may adhere to the sample support600or the detection element500in the same manner. Alternatively, coating with a material with hydrophilicity may be performed in order to facilitate the mounting of the sample that contains a large amount of liquid. Alternatively, coating with a material with high affinity with a biological sample such as collagen may be performed in order to facilitate mounting or cultivation of living cells or bacteria. Coating described herein widely includes methods of causing a coating material to adhere to the surface of the sample support, such as spraying, dipping, and coating. In addition, the molecule or the film may be arranged only at a predetermined position. The predetermined position described herein means a partial region in the detection element500. In a case in which the molecule in the positively charged state is arranged only at the predetermined position, for example, it is possible to arrange the sample only at the predetermined position in a case in which the sample is a biological sample such as cells. This method is effective when it is desired to shorten the observation time by narrowing a region as a target of observation. In addition, a conductive member (electrification prevention member) may be provided at least on the surface on which the sample is placed in order not to cause electrification during irradiation with the charged particle beam. Examples of the conductive member include a carbon material, a metal material, and a conductive organic substance. Such a molecule, a coating material, an electrification preventing film, and the like are arranged at the position represented as A inFIG. 6(a).

The detection element500may slightly project from the surface of the sample support600as illustrated inFIG. 7(a)as long as it is possible to mount the sample in the same manner as that in which the user previously experienced and felt. For example, the fabrication can be made by a method of attaching the detection element500with a thickness of several hundreds of μm or less to the base501. In such a case, since the base501has a significantly simple shape and the area of the detection element500is small, it is possible to produce the sample support at low cost. In addition, the thickness of the transparent member may be the same as that of the detection element, and such a shape that a portion from the upper surface to the lower surface of the sample support is made to function as the detection element500may be employed as illustrated inFIG. 7(b)as long as it is possible to produce or obtain the detection element500itself at low cost. In such a case, the base501functions as a base for supporting the detection element500.

The entire sample support600may be made to function as the detection element500as illustrated inFIG. 8as long as it is possible to produce the detection element500at significantly low cost. That is, the base501is not provided.FIG. 8(a)illustrates a simple flat sample support such as a slide glass. In contrast,FIGS. 8(b) and 8(c)illustrate examples in which the sample support has concave shapes. The sample is placed in the concaves and does not leak even in a case of a liquid sample.FIG. 8(b)illustrates a sample container configured such that the sample does not leak from side surfaces, such as a petri dish, and FIG.8(c) illustrates a culture container (a micro plate or a titer plate) with a plurality of places where the sample is stored. The light-emitting member may have anyone of the shapes inFIGS. 8(a), 8(b), and 8(c), or may have a shape other than the shapes illustrated in the drawings. In this case, there is an advantage in that production cost is not required since only one type of material is used.

If it is necessary that the detection element500has the same size as that of a slide glass with which the user is familiar, it is also possible to just attach the detection element500to the slide glass as illustrated inFIG. 7(a). By producing the detection element500to have the same size as that of the slide glass, enhanced convenience is achieved in a case in which the detection element500is stored in a case for the slide glass, in a case in which the detection element500is mounted to a sample holder for the slide glass, and in a case in which the detection element500is mounted to a sample stage with a size of the slide glass of the optical microscope, for example. In a case in which the detection element500is a plastic scintillator configured of plastic, the sample support inFIG. 8(a)itself can be formed to have the size of the slide glass as long as it is possible to produce the sample support at significantly low cost.

As illustrated inFIG. 9, the sample support according to the embodiment can be integrated with a culture container. This example is preferable because in a case in which the sample is a biological sample, it is possible to culture or cultivate a sample on the light-emitting member and to omit an operation of moving the sample to the sample support. A container700is arranged on the sample support600(FIG. 9(a)). The container700is a cylindrical tubular member with opened surfaces on upper and lower sides, for example. Next, the sample6such as cells and a culture medium701that contains a nutritional material capable of providing nutrition and energy to the sample, such as a culture solution, are mounted on the inside of the container700(FIG. 9(b)). The form of the culture medium.701may be any one of solid, liquid, and gas. In addition, a leakage prevention member such as a rubber or a packing may be provided in order not to cause the culture medium701to leak from a space between the sample support600and the container700. Thereafter, the sample is cultured, and the culture medium701such as a culture solution is then removed (FIG. 9(c)). Then, it is possible to obtain a state in which the sample6adheres to the detection element500by peeling off the container700from the sample support600(FIG. 9(d)). Although only one detection element500and only one container700are illustrated in the drawings, a plurality of detection elements500and a plurality of containers700may be arranged on a single sample support. In addition, it is necessary that the sample is thin since the charged particle beam (and light in a case of the transmission optical observation) is required to be transmitted therethrough. For example, the thickness is from about several tens of nm to about several tens of μm. Therefore, it is necessary that the aforementioned cultured cells have substantially the same thickness as that described above after the culture. Examples of the cultured cells include cultured nerve cells, blood cells, and iPS cells. Alternatively, the cultured cells may be bacteria or viruses. By using the method, it is possible to obtain a transmission charged particle microscope image and an optical microscope image while the cell sample cultured on the sample support600remains mounted on the sample support600.

Alternatively, it is only necessary to place the detection element500on an existing culture container as illustrated inFIG. 10(a). An example in which a sample is arranged by the method will be shown inFIG. 10(b). Here, an exemplary procedure for culturing a cultured cell on the detection element500and observing the cultured cell with a charged particle microscope apparatus and an optical microscope apparatus will be described. First, the light-emitting member500with a desired size is placed in advance in a culture container808as illustrated inFIG. 10(a). Then, a culture solution806, a sample807, and the like are injected as illustrated inFIG. 10(b), and culture and the like is made to proceed. Next, the detection element500is extracted while the sample807is mounted thereon as illustrated inFIG. 10(c). Then, observation with the optical microscope602and the charged particle microscope601can be performed by extracting the detection element500as necessary as illustrated inFIG. 10(d)after performing desired pre-processing such as fixing, drying processing, metal dyeing, or immunostaining. In addition, the observation can be performed without any additional operation in the case of the observation with the optical microscope, or the observation may be performed after arranging the detection element500on a transparent member such as a slide glass. In addition, a culture container (a micro plate or a titer plate) that is capable of performing a plurality of culture operations as illustrated inFIG. 11may be used as the culture container. In such a case, it is possible to prepare a plurality of samples at the same time by placing a plurality of detection elements500in advance. If the detection element500as the light-emitting member is an inexpensive detection element with high workability, such as a plastic scintillator, as described above, the culture container808itself may be used as the detection element500.

The sample support600can be used not only with the charged particle beam microscope but also with the optical microscope, and it is also possible to observe the sample on the sample support with an inverted optical microscope in which a field lens251is arranged on the opposite side to the surface to which the sample is mounted as will be described later. In such a case, there is a case in which it is desired to cause the field lens251of the optical microscope to approach the sample as much as possible. If the distance between the field lens251and the sample6is represented as L, there is a case in which it is desired to set L to be equal to or less than about several hundreds of μm.

Although a method is considered in which the entire sample support600provided with the detection element500is formed to have a thin thickness of equal to or less than the distance L, there is a case in which intensity is low since the sample support600itself is excessively thin. Thus, it is also possible to form a transparent member at a portion, on which the sample is placed, of the sample support to be thinner than the other portions. That is, it is possible to set the distance between the sample6and the field lens251to be L by producing regions with thinner thickness at the portion at which the sample is arranged and at the detection element500as compared with the thickness of the sample support600(B in the drawing) as illustrated inFIG. 12(a). In doing so, it is possible to keep the strength of the sample support600itself high since both ends of the sample support are thick. The thick regions on both ends may be arranged on the opposite side as illustrated inFIG. 12(b)or the thick regions may be provided on both upper and lower sides of the sample placement surface as long as the user can mount the sample in the same manner as that in which the user previously experienced or felt.

In addition, a paper or a seal portion on which information related to the sample6, such as characters, numbers, barcodes, pictures, and the like can be written may be provided on the sample support600. In such a case, it becomes easier to manage the sample6that is mounted to the sample support.

Although not shown in the drawing, ion liquid may be arranged above, inside, or around the sample to be observed. The ion liquid has a characteristic that it is possible to apply conductivity to an electron irradiation surface. By arranging the ion liquid inside or around the sample to be observed, it is possible to prevent electrification of the sample during irradiation with the charged particle beam in vacuum. Furthermore, it is possible to maintain the sample in a wet state by causing the sample to contain the ion liquid. Therefore, it is possible to obtain a transmission image of the wet sample by detecting light emitted by the charged particle beam that has been transmitted through or scattered in the wet sample containing the ion liquid. As a method of mounting the ion liquid to the sample, the sample may be dipped in the ion liquid, or the ion liquid may be sprayed to the sample.

Although not shown in the drawing, if contamination, scratch, or the like is present before usage of the detection element500, a flat surface may be obtained by cleaning the detection element500with an organic solvent or the like in advance, polishing the detection element500by using a mechanical or chemical polishing agent, or sputtering the detection element500by an ion beam or the like. In addition, a member, through which the charged particle beam can be transmitted, which is as transparent as possible with respect to the light from the light source of the optical microscope and the light emitted by the detection element500may be arranged or applied in order not to cause the scratch and the contamination to appear outstandingly.

<Description of Method and Principle>

Hereinafter, descriptions will be given of a light detection method using the sample support according to the embodiment and a principle in which the transmission charged particle beam can be obtained.FIG. 13illustrates a state in which the sample6is arranged on the detection element500. A light detector503is illustrated below the sample support. The light detector503can transform or amplify the light signal from the detection element500into an electrical signal. The transformed or amplified electrical signal is input to a control unit or a computer via a communication line, and such a control system forms an image therefrom. The obtained image (transmission charged particle beam image) may be displayed on a monitor or the like.

Here a case will be considered in which a site508with high density and a site509with low density are present in a sample. If the site508with high density in the sample is irradiated with the primary charged particle beam510, a major part of the charged particle beam is backscattered. Therefore, the charged particle beam does not reach the detection element500. In contrast, if the site509with low density in the sample is irradiated with the primary charged particle beam511, the charged particle beam can be transmitted up to the detection element500. As a result, it is possible to detect a difference in density inside the sample (that is, convert the difference into a light signal) by the detection element500. The transmission level varies depending on acceleration energy of the charged particle beam. Therefore, it is possible to change internal information to be observed and a region thereof by changing the acceleration energy of the charged particle beam.

Although there may be a space between the light detector503and the sample support (the portion h in the drawing), it is preferable that the height h thereof is as short as possible in order to most efficiently detect the light. The sample support may be in contact with the light detector503. In addition, the light may be most efficiently detected by increasing a light-receiving area of the light detector503. Alternatively, a light-transmission path for efficiently delivering the light to the portion h between the sample support and the light detector503. As an example,FIG. 14illustrates an example in which a light transmission path811is provided between the detector and the light-emitting member. It is assumed that the sample support600is arranged on the sample stage5. The light transmission path811through which the light is delivered to a lower portion of the sample stage is formed of a light reflective material809for causing the light to pass without leaking to the outside of the light transmission path811and a light reflective material810for guiding the light to the light detector503. A configuration of the light transmission path811is not limited to the example.

The light emitted by the detection element500passes to reach the lower portion of the sample support600inFIG. 14and is incident on the light transmission path811. A track of the light that enters the light transmission path is controlled by the light reflective material809. An advancing direction of the light that has reached the light reflective material810is changed to a direction toward the detection element503by the light reflective material810, and the light passes through the light transmission path811and is then detected by the detection element503. The light transmission path811may be a solid substance capable of delivering the light or may deliver the light in the air or in vacuum. Examples of the solid material capable of allowing passage of the emitted light in the wavelength region include a transparent or semi-transparent material with respect to the light such as quartz, glass, optical fiber, or plastic. With such a configuration, it is possible to arrange the light detector503so as to be separate from the stage and to thereby arrange the wiring and the electric circuit to be connected to the light detector503at positions that are separate from the sample support and the sample stage for holding the sample support. Although the light detector503is arranged below the sample support600inFIGS. 13 and 14, the light detector503may be arranged in the lateral direction or above the sample support600as will be described later.

Here, a description will be given of a region from which light is emitted by irradiation of the detection element500with the charged particle beam that has passed through the sample, with reference toFIG. 15. The sample6adheres to or is in contact with a sample adhesion layer812on the detection element500. As described above, the sample adhesion layer is a layer that is configured such that cells or the like can easily adhere thereto, a conductive film layer for removing electrification due to the charged particle beam, or the like. If the width thereof in the thickness direction is assumed to be represented as A, it is necessary that the width A is thin enough to cause the charged particle beam flying with energy from about several keV to about several tens of keV to reach the light-emitting member. This is from about several nm, to about several hundreds of nm, for example. The charged particle beam that has passed through the sample adhesion layer812enters the detection element500and causes light emission814. The light-emitting region813that emits light depends on the depth of the entrance of the charged particle beam and energy at the time of the entrance and during the entrance. In a case of the charged particle beam with energy from about several keV to about several tens of keV, for example, the light-emitting region813ranges from about several tens of nm to about several μm. If the thickness is assumed to be represented as B and the thickness of the detection element500is thicker than the width B, a region (C in the drawing) other than the region represented with the width B does not contribute to the light emission. In order to detect the light emission on the lower side in the drawing, it is desirable that the region C that does not contribute to the light emission and the sample support600are transparent enough to minimize a loss of the light emission. Although not shown in the drawing, the light from the light-emitting region813is scattered in various directions inside the detection element500. Thus, it is also possible to deliver the whole light to the lower side in the drawing by providing a metal film capable of reflecting the light to the portion A in the drawing or to the side surface side of the detection element500to prevent the generated light from escaping to the upper side in the drawing and the side surface side.

A method of mounting the sample to the sample support will be described below. Since it is necessary to transmit the charged particle beam (and light in a case of using the optical microscope observation together), the sample is required to be thin. For example, the thickness is from about several tens of nm to about several tens of μm. Examples of the sample that can be mounted directly on the detection element500include liquid or mucosa containing cells, liquid-form biological specimens such as blood or urine, cells split into a piece, particles in a liquid, fine particles such as fungi, mold, and viruses, and a soft material containing fine particles and an organic substance. As a method of mounting the sample, the following methods can be considered as well as the aforementioned culture. For example, there is a method of dispersing the sample in a liquid and causing the liquid to adhere to the detection element. Alternatively, the sample may be split into a piece with a thickness through which the charged particle beam can be transmitted, and the sample split into the piece may be arranged on the detection element. More specifically, the sample may be made to adhere to a tip end of a cotton swab and applying the sample to the detector or dropping the sample with a dropper. In the case of fine particles, the detector may be sprinkled with the fine particle. Coating of the sample may be performed by spraying the sample, a spin coating method of coating the sample support with liquid during high-speed rotation may be used, or a dip coating method of coating the sample support with liquid by dipping the sample support into the liquid and extracting the sample support therefrom may be employed. Any methods may be employed as long as the sample can have a thickness from about several tens of nm to about several tens of μm.

Next, a description will be given of an exemplary procedure before observation with a microscope with reference toFIG. 16. First, the detection element500(the light-emitting sample support) to mount a sample thereon is prepared. Next, predetermined members are arranged on the detection element500as necessary. Here, the predetermined members mean the substance for enhancing the adhesiveness between the sample and the sample support, the conductive substance, the substance for reflecting light, or some predetermined gas material as described above. If it is not necessary to arrange the predetermined members, it is not necessary to perform this step. Then, the sample is mounted to the detection element500. Next, the processing proceeds to a step in which the detection element is mounted to and observed on the charged particle microscope or the optical microscope. Step A is a step of performing observation with the charged particle microscope, and Step B is a step of performing observation with the optical microscope. In Step A, the detection element500with the sample mounted thereto as described above is arranged in the charged particle microscope apparatus first. Then, the charged particle beam is made to be transmitted through or scattered in the sample by irradiating the sample with the charged particle beam. Then, since the detection element500emits light when the charged particles reach the detection element, the light emission is detected by the light emission detector. Next, a lower-order control unit37or the like generates a transmission charged particle image of the sample from the signal detected by the detector. After the observation with the charged particle microscope apparatus is completed, the sample is extracted to the outside of the charged particle microscope apparatus. The processing proceeds to Step B of performing observation with the optical microscope as necessary. In Step B of performing observation with the optical microscope, the detection element500with the sample mounted thereto is arranged in the optical microscope apparatus first. If it is necessary that the detection element500has the shape of the slide glass when the detection element500is arranged in the optical microscope apparatus, it is possible to place the detection element500on the slide glass as described above. Next, observation with the optical microscope is performed. After the observation is completed, the detection element500may be returned to the charged particle microscope apparatus again for further observation. Steps A and B may be replaced with each other, and the observation may be performed at the same time in a case of an apparatus in which the charged particle microscope apparatus and the optical microscope apparatus are integrated, as will be described later.

<Description of Observation with Charged Particle Beam Apparatus in Vacuum>

Here,FIG. 17illustrates a typical charged particle beam apparatus to which the sample support according to the embodiment is mounted. The charged particle microscope is configured mainly of a charged particle optical column2, a case body7(hereinafter, also referred to as a vacuum chamber) that supports the charged particle optical column relative to an apparatus installation surface, and a control system that controls the charged particle optical column2and the case body7. When the charged particle microscope is used, the inside of the charged particle optical column2and the case body7are evacuated by a vacuum pump4. An activation operation and a stop operation of the vacuum pump4are also controlled by the control system. Although only one vacuum pump4is illustrated in the drawing, two or more vacuum pumps4may be provided.

The charged particle optical column2is configured of elements such as a charged particle source8that generates the primary charged particle beam and an optical lens1that focuses the generated charged particle beam, guides the generated charged particle beam to a lower portion of the column, and scans the sample6with the primary charged particle beam. The charged particle optical column2is installed so as to project toward the inside of the case body7and is fixed to the case body7via a vacuum sealing member123. A detector3that detects secondary charged particles (secondary electrons, reflected electrons, or the like) that are obtained by irradiation with the primary charged particle beam is arranged at an end of the charged particle optical column2. The detector3may be provided at any locations in the case body7instead of the location illustrated in the drawing.

The secondary charged particles such as reflected charged particles or transmission charged particles are released from the inside or the surface of the sample by the charged particle beam that has reached the sample6. The secondary charged particles are detected by the detector3. The detector3is a detection element that is capable of detecting and amplifying the charged particle beam that flies with energy from several keV to several tens of keV. For example, a semiconductor detector made of a semiconductor material such as silicon or a scintillator that is capable of transforming a charged particle signal into light on or inside a glass surface is employed.

The charged particle microscope according to the embodiment includes, as control systems, a computer35that is used by a user of the apparatus, an upper-order control unit36that is connected to the computer35and performs communication, and a lower-order control unit37that controls a vacuum evacuation system, a charged particle optical system, and the like in response to an order that is transmitted from the upper-order control unit36. The computer35is provided with a monitor that displays an apparatus operation screen (GUI) and input means for the operation screen, such as a keyboard and a mouse. The upper-order control unit36, the lower-order control unit37, and the computer35are respectively connected via communication lines43and44.

The lower-order control unit37is a site that transmits and receives control signals to control the vacuum pump4, the charged particle source8, the optical lens1, and the like, further transforms a signal output from the detector3into a digital image signal, and transmits the digital image signal to the upper-order control unit36. In the drawing, the signal output from the detector3is connected to the lower-order control unit37via an amplifier53such as a preamplifier. The amplifier may not be provided if not necessary.

According to the upper-order control unit36and the lower-order control unit37, an analog circuit, a digital circuit, and the like may be present together, or the upper-order control unit36and the lower-order control unit37may be collectively provided as one control unit. The configuration of the control systems illustrated inFIG. 17is only an example, and modification examples of the control units, the valve, the vacuum pump, the communication wiring, and the like belong to the scope of the charged particle beam microscope according to the embodiment as long as the control units, the valve, the vacuum pump, the communication wiring, and the like function as intended in the embodiment.

Vacuum piping16with one end connected to the vacuum pump4is connected to the case body7such that the inside thereof can be maintained in a vacuum state. Also, a leak valve14for opening the inside of the case body to the atmospheric air is provided such that the inside of the case body7can be opened to the atmospheric air when the sample support is introduced into the apparatus. No leak valve14may be provided, or two or more leak valves14may be provided. In addition, the arrangement location of the leak valve14on the case body7is not limited to the position illustrated inFIG. 17, and the leak valve14may be arranged at another position on the case body7.

The case body7includes an opening portion provided in the side surface thereof, and the inside of the apparatus is maintained in an air tight vacuum state by a cover member122and a vacuum sealing member124for the opening portion. The charged particle microscope according to the embodiment is provided with the sample stage5for changing the positional relationship between the sample and the charged particle optical column after placing the sample mounted to the sample support inside the case body7as described above. The aforementioned light-emitting member or the sample support including the light-emitting member is detachably arranged on the sample stage5. A support panel107that functions as a bottom panel supported by the cover member122is attached, and the stage5is fixed to the support panel107. The stage5is provided with an XY drive mechanism in an in-plane direction, a Z-axis drive mechanism in a height direction, and the like. The support panel107is attached so as to be directed to a facing surface of the cover member122and stretch toward the inside of the case body7. Support shafts extend from the Z-axis drive mechanism and the XY drive mechanism, respectively and are connected to an operation grip51and an operation grip52included in the cover member122, respectively. The user of the apparatus can adjust the position of the sample by operating the operation grips. In addition, a configuration is also applicable in which the optical microscope can be provided on the cover member122as will be described later.

It is possible to mount the sample support600provided with the detection element500on the sample stage5. As described above, the detection element500transforms the charged particle beam into light. The light detector503for detecting the light, transforming the light into an electrical signal, and amplifying the signal is provided on the sample stage5or in the vicinity of the stage. As described above, the sample support provided with the detection element500may be located at a close position to the light detector or may be in contact with the light detector in order to efficiently detect the light signal. In addition, the light transmission path may be arranged therebetween. Although the light detector is provided on the sample stage in the drawing, the light detector503may be fixed to any location of the case body7or may be provided outside the case body7. In a case in which the light detector503is provided outside the case body7, the light detector can detect the light signal transformed by the detection element500by the light transmission path for delivering the light, such as glass or optical fiber, being located in the vicinity of the sample support500and the light signal being delivered through the light transmission path. The light detector is a semiconductor detection element or a photo-multiplier, for example. In any cases, the light detector according to the embodiment detects the light that is emitted by the detection element of the aforementioned sample support and passes through the transparent member.

The drawing illustrates a state in which the light detector503is provided on the stage5. A preamplifier substrate505is connected from the light detector503provided on the stage5via wiring504. The preamplifier substrate505is connected to the lower-order control unit37via wiring507. Although the preamplifier substrate505is inside the case body7in the drawing, the preamplifier substrate505may be outside the case body7. There is a projection506on the sample stage5, and the sample support600is arranged by using the projection506. In doing so, it is possible to fix the sample support5and prevent positional deviation. In addition, fixation to the sample support600can be made with a double-stick tape or the like on the stage5. However, in the case in which the sample support according to the embodiment is used with the optical microscope as described above, it is not preferable to attach the double-stick tape to the lower surface of the sample support600, and it is desirable to attach a positional deviation prevention member to the side surface or the like of the sample support600with a double-stick tape or the like. Since the light detector503is arranged immediately below the base501if the sample support600is mounted to the light detector503, it is possible to efficiently detect the light that is transmitted through the sample6and is emitted by the detection element500. By such an apparatus and a method, it is possible to obtain a transmission charged particle image by using the charged particle beam apparatus. Furthermore, in a case in which the sample support according to the embodiment is formed of a transparent member, it is possible to perform observation with the optical microscope after extracting the sample support to the outside of the charged particle beam apparatus.

In addition, since the charged particle beam apparatus according to the embodiment includes both the detector3and the detection element500, it is possible to cause the detector3to obtain the secondary charged particles that are generated or reflected by the sample and to cause the detection element500to obtain the transmission charged particles that are transmitted through or scattered in the sample. Accordingly, it is possible to switch display of a secondary charged particle beam image and a transmission charged particle image on the monitor35by using the lower-order control unit37or the like. In addition, it is possible to display two kinds of images at the same time.

<Description of Observation with Charged Particle Beam Apparatus Under Atmospheric Pressure>

Next, a description will be given of a configuration in which the embodiment is applied to a charged particle beam apparatus capable of performing observation under an atmospheric pressure with reference toFIG. 18. The charged particle beam apparatus according to the embodiment is configured mainly of the charged particle optical column2, the first case body (hereinafter, also referred to as a vacuum chamber)7that supports the charged particle optical column with respect to the apparatus installation surface, a second case body (hereinafter, also referred to as an attachment)121that is used in a state of being inserted into the first case body7, the sample stage5that is arranged in the second case body, and a control system that controls the charged particle optical column2, the first case body7, the second case body121, and the sample stage5. Since basic configurations of the control system and the like are the same as those inFIG. 18, detailed descriptions thereof will be omitted.

At least one of side surfaces of a rectangular parallelepiped shape of the second case body121is an opened surface. The surfaces other than the surface, on which a barrier membrane holding member155is installed, among the side surfaces of the rectangular parallelepiped shape of a main body121are configured of walls of the second case body121. Alternatively, the second case body121itself may be not provided with a wall and may be configured of side walls of the first case body7in a state of being assembled in the first case body7. The second case body121is inserted into the first case body7through the opening portion and has a function of accommodating the sample6as a target of observation in a state of being assembled in the first case body7. The first case body7and the second case body121are connected via a vacuum sealing member126and are fixed to an outer wall surface of the side surface side. The second case body121may be fixed to any of the side surface and the inner wall surface of the first case body7and the charged particle optical column. In doing so, the entire second case body121is fitted into the first case body7. The aforementioned opening portion is most simply produced by utilizing an opening for carrying in and out the sample, which is originally provided in the vacuum sample chamber of the charged particle microscope. That is, if the second case body121is produced so as to match the size of the hole that is originally provided and the vacuum sealing member126is attached to the circumference of the hole, a modification of the apparatus can be minimized. In addition, the second case body121can be detached from the first case body7.

The side surface of the second case body121is an opened surface that communicates with an atmospheric air space through a surface with at least a size that allows carrying in and out of the sample, and the sample6that is accommodated in the second case body121is maintained in an atmospheric pressure state, a slightly negatively pressurized state, or a desired gas type state during the observation. AlthoughFIG. 18is a sectional view of the apparatus in a direction parallel to the optical axis and only one opened surface is illustrated, the number of the opened surfaces of the second case body121is not limited to one as long as the vacuum sealing is established with the side surfaces of the first case body in the further direction and the closer direction of the paper inFIG. 18. It is only necessary that at least one or more opened surfaces are provided in the state in which the second case body121is assembled in the first case body7. By the opened surfaces of the second case body, the sample can be carried in and out between the inside and the outside of the second case body (attachment).

A barrier membrane10through which the charged particle beam can be transmitted and pass is provided on the upper surface side of the second case body121. The barrier membrane10can be attached to and detached from the second case body121. The vacuum pump4is connected to the first case body7and evacuates a closed space (hereinafter, referred to as a first space) that is configured of the inner wall surface of the first case body7, the outer wall surface of the second case body, and the barrier membrane10. In doing so, the first space11is maintained in a highly vacuum state by the barrier membrane10while a second space12is maintained in a gas atmosphere at the atmospheric pressure or at substantially the same pressure as the atmospheric pressure in the embodiment. Therefore, it is possible to maintain the side of the charged particle optical column2in the vacuum state and to maintain the sample6and the aforementioned sample support at the atmospheric pressure or a predetermined atmospheric pressure during an operation of the apparatus. The barrier membrane10is held by the barrier membrane holding member155, and exchange of the barrier membrane10can be achieved by exchanging the barrier membrane holding member155.

In the case of the charged particle microscope according to the embodiment, the opened surface that configures at least one side surface of the second case body121can be covered with a cover member122. The cover member122is provided with the sample stage and the like.

The charged particle microscope according to the embodiment has a function of supplying replacement gas to the inside of the second case body121and a function with which it is possible to form a pressure state that is different from that of the first space. The charged particle beam that is released from the lower end of the charged particle optical column2passes through the first space that is maintained at the highly vacuum state, passes through the barrier membrane10illustrated inFIG. 18, and further enters the second space that is maintained in the atmospheric pressure state or the slightly negatively pressurized state. That is, the second space is in a state in which a level of vacuum is lower than that in the first space (lower vacuum level). Since the charged particle beam is scattered by gas molecules in the atmospheric air space, the mean free path becomes short. That is, if the distance between the barrier10and the sample6is long, the primary charged particle beam, or the secondary charged particles, reflected charged particles, or transmission charged particles that are generated by irradiation with the primary charged particle beam do not reach the sample, the detector3, and the detection element500. In contrast, the probability of scattering of the charged particle beam is proportional to the mass number and density of gas molecules. Therefore, it is possible to lower the probability of scattering of the charged particle beam and cause the charged particle beam to reach the sample by replacing the second space with gas molecules with a smaller mass number than that of the atmospheric air or by slightly performing vacuuming. In addition, it is only necessary that the air in at least the path, through which the charged particle beam passes, in the second space, that is, the atmospheric air in the space between the barrier membrane and the sample instead of the air in the entire second space can be replaced with the gas. If nitrogen or water vapor that is gas lighter than the atmospheric air is employed as the type of the replacement gas, it is possible to observe an effect of improving S/N in an image. However, the effect of improving S/N in the image is higher when helium gas or hydrogen gas with smaller mass is used.

For the aforementioned reason, an attachment portion (gas introduction portion) of the gas supply tube100is provided in the cover member122in the charged particle microscope according to the embodiment. The gas supply tube100is coupled to a gas tank103at the coupling portion102, and thereby introducing the replacement gas into the second space12. A gas control valve101is arranged at a mid-way point of the gas supply tube100so as to be able to control the flow volume of the replacement gas flowing through the tube. Therefore, a signal line extends from the gas control valve101to the lower-order control unit37, and the user of the apparatus can control the flow volume of the replacement gas on the operation screen that is displayed on a monitor of the computer35. In addition, the gas control valve101may be opened and closed through manual operations.

Since the replacement gas is light element gas, the replacement gas is easily accumulated in the upper portion of the second space12, and the air on the lower side thereof is not easily replaced. Thus, an opening that communicates between the inside and the outside of the second space is provided on the lower side than the attachment position of the gas supply tube100in the cover member122. For example, the opening is provided at an attachment position of a pressure adjustment valve104inFIG. 18. In doing so, the atmospheric gas is pressed by the light element gas introduced from the gas introduction portion and is then discharged from the opening on the lower side. Therefore, it is possible to efficiently replace the inside of the second case body121with the gas. In addition, the opening may be made to also function as a rough exhaust port which will be described later.

There is a case in which the electron beam is greatly scattered even in the light element gas such as helium gas. In such a case, it is only necessary to replace the gas tank103with a vacuum pump. By slightly performing vacuum drawing, it is possible to bring the inside of the second case body into a significantly low vacuum state (that is, an atmosphere at a pressure that is close to the atmospheric pressure). For example, a vacuum exhaust port is provided in the second case body121or the cover member122, and the inside of the second case body121is vacuum-exhausted once. Thereafter, the replacement gas may be introduced. Since it is only necessary to reduce atmospheric gas constituents remaining inside the second case body121to a predetermined amount or less, high-vacuum exhaust is not required, and rough exhaust is sufficient as the vacuum exhaust in this case.

However, in a case of observing a sample that contains moisture such as a biological sample, for example, moisture is evaporated from the sample that is placed in the vacuum state once, and the state thereof varies. Therefore, it is preferable to perform the observation before complete evaporation or to introduce the replacement gas directly from the air atmosphere as described above. By closing the aforementioned opening with the cover member after the introduction of the replacement gas, it is possible to effectively seal the replacement gas in the second space.

As described above, in the embodiment, it is possible to control the space where the sample is placed to an arbitrary level of vacuum from the atmospheric pressure (about 105Pa) to about 103Pa. According to a so-called low-vacuum scanning electron microscope in the related art, since an electron beam column communicates with a sample chamber, a pressure in the electron beam column varies in conjunction with a pressure in the sample chamber if the degree of vacuum in the sample chamber is lowered to obtain a pressure that is close to the atmospheric pressure, and it is difficult to control the sample chamber to the pressure from the atmospheric pressure (about 105Pa) to 103Pa. According to the embodiment, since the second space is separate from the first space with a thin film, it is possible to freely control the pressure and the gas type in the atmosphere in the second space that is surrounded by the second case body121and the cover member122. Accordingly, it is possible to realize the control of the sample chamber to the pressure from the atmospheric pressure (about 105Pa) to 103Pa, which is difficult in the related art. Furthermore, it is possible to observe states of the sample while continuously varying the pressure to other pressures around the atmospheric pressure in addition to the observation at the atmospheric pressure (about 105Pa).

If a three-way valve is attached to the position of the opening, the opening can be made to function both as a rough exhaust port and as an exhaust opening for atmospheric air leakage. That is, it is possible to realize the exhaust opening that is made to function both as the rough exhaust port and as the exhaust opening by attaching one way of the three-way valve to the cover member122, connecting another way thereof to the vacuum pump for rough exhaust, and attaching the leak valve to the other way.

The pressure adjustment valve104may be provided instead of the aforementioned opening. The pressure adjustment valve104functions so as to automatically open when the internal pressure of the second case body121becomes equal to or greater than 1 atm. By providing the pressure adjustment valve with such a function, it is possible to discharge the atmospheric gas constituents such as nitrogen and oxygen to the outside of the apparatus by automatically opening the pressure adjustment valve when the internal pressure becomes equal to or greater than 1 atm during introduction of the light element gas and to fill the inside of the apparatus with the light element gas. In addition, the gas tank or the vacuum pump103illustrated in the drawing is provided in the charged particle microscope in some cases, or the user of the apparatus attaches the gas tank or the vacuum pump103thereto later in other cases.

The sample support provided with the detection element500can be mounted to the sample stage5of the charged particle beam apparatus. In the state in which the aforementioned sample support is placed on the sample stage, the detection element500is in a state of being placed on the opposite side of the barrier membrane with respect to the sample. Arrangement configurations of the light detector503and the like in the vicinity of the sample stage are the same as those inFIG. 17. In the case of this configuration, it is possible to obtain a transmission charged particle beam signal in which variations in forms such as moisture evaporation that is caused by vacuum drawing are minimized. In addition, since it is not necessary to perform the vacuum drawing until the sample space becomes a highly vacuum state, it is possible to obtain a transmission charged particle beam microscope image of the sample on the sample support600at a significantly high throughput.

<Description of Observation with Optical Microscope>

FIG. 19illustrates a case of performing observation with an optical microscope. First, a description will be given of an optical microscope250. The optical microscope250is provided with optical lenses such as a field lens252. Microscope information through the optical lens is projected to an ocular lens207. Alternatively, the microscope information may be transformed into a digital signal by a CCD camera and may be displayed on a monitor which is not shown in the drawing. The sample support600according to the embodiment is arranged on a sample stage258that is provided with drive mechanisms204such as an XY drive mechanism that can be moved in the lateral direction in the drawing or in the paper plane direction with respect to an optical axis251of the optical microscope and a Z-axis drive mechanism that can change the distance from the field lens252. An opening portion259is provided around the optical axis251of the optical microscope on the sample stage258, and the sample support600according to the embodiment is arranged over the opening portion. The optical microscope250is provided with light sources that are capable of emitting white light, ultraviolet light, light with a controlled wavelength, or a photon beam such as a laser. The light sources include a light source255for emitting light from the upper side of the sample support600in the drawing and a light source256for emitting light from the lower side of the sample support600. In addition, the light source may be a light source of a room where the optical microscope250is arranged or solar light. For the light source, supply and control are performed to adjust the light intensity of the light and the power source for turning on and off the light by a communication line, an electric line, or the like which is not shown in the drawing. Although the light sources are arranged at the aforementioned two locations in the drawing, at least one light source may be provided. Although the example of two light source locations was described above, the light sources may be arranged at other locations. In order to change an observation magnifying power or a focus position of the sample6on the sample support, the optical microscope250includes an optical lens drive mechanism253. By moving the field lens252in a direction of the optical axis251of the optical microscope by the optical lens drive mechanism253, it is possible to adjust the focal point on the sample6on the sample support600. Although not shown in the drawing, the focal point may be changed by moving the optical lens inside the optical microscope250in the direction of the optical axis251instead of the field lens252.

The light emitted from the light source256is released from the field lens251or a circumference thereof via a mirror or the like in the optical microscope250and reaches the sample support600. The photon beam that has reached the sample support600passes through the base501and the detection element500and reaches the sample. Reflected light that has been reflected by the sample passes through the detection element500and the base501again and reaches the field lens251. In doing so, an image is formed inside the optical microscope251from a signal of light with which the field lens251is irradiated, and the observation of the sample with the optical microscope can be performed through the ocular lens207. In a case in which the light source position corresponds to the light source255, the sample is irradiated with the photon beam released from the light source255first. It is possible to form the optical microscope image by causing the photon beam that has been transmitted through the sample to pass through the detection element500and the base501and pass through the field lens.

Although the optical microscope described with reference to the drawing is an inverted optical microscope in which the optical lens and the like are arranged below the sample, an upright optical microscope in which the optical system is arranged above the sample is also employed. In such a case, the light sources may be placed at any arbitrary locations.

The method and apparatus for observing the sample6on the sample support600according to the embodiment with the optical microscope was described hitherto. If the detection element500and the base501are transparent with respect to the light from the light sources as described above, it is possible to perform the observation with the optical microscope while transmitting light through the sample and the sample support, and also, it is possible to obtain a charged particle microscope image in vacuum or in the atmospheric air by the charged particle beam microscope apparatus as illustrated inFIGS. 17 and 18.

Second Embodiment

In the first embodiment, the configuration in which the light emitted by the detection element500passes through the detection element500and the sample support600and the light is detected below the detection element500or the sample support600was described. In this embodiment, configurations of a sample support and an apparatus in which the light generated by the detection element500is detected on the upper side or the lateral side of the detection element500or the sample support600will be described. Since portions that are not particularly stated in this embodiment, such as the material and the shape of the detection element500and provision of the layer for facilitating the adhesion of the sample to the detection element and the conductive film layer for removing the electrification due to the charged particle beam, are the same as those in the first embodiment, the detailed descriptions thereof will be omitted.

First, a description will be given of principles of light generation and emitted light detection with reference toFIG. 20. The sample6is made to adhere to or is in contact with the sample adhesion layer812on the detection element500. Since the sample adhesion layer is the same as that in the first embodiment, a detailed description thereof will be omitted. The charged particle beam that has passed through the sample adhesion layer812enters the detection element500, and the light emission814is caused. If the charged particle beam that has been transmitted through or scattered in the sample6reaches the detection element500, ultraviolet light, visible light, infrared light, or the like is emitted. The wavelength of the emitted light may be any wavelength within a wavelength range that can be detected by the detector. Since the thickness B of the light-emitting region is the same as that in the first embodiment, a detailed description thereof will be omitted. If it is considered that the site508with high density and the site509with low density are present in the sample in the same manner as in the first embodiment, the charged particle beam can be transmitted up to the detection element500if the site509with low density in the sample is irradiated with the primary charged particle beam511. The light814that is generated in the light-emitting region813with low density below the sample is released to the upper side in the drawing as well as the lower side in the drawing. That is, even if the charged particle beam is scanned and a light signal at the scanning position is obtained on the upper side than the sample, the obtained light signal is transmission information inside the sample6or a signal representing a transmission image. According to this principle, the region C that does not contribute to the light-emitting region in the detection element500is not necessarily transparent. Similarly, the sample support600is not necessarily transparent. For example, the sample support600may be a metal member made of aluminum, for example. In a case in which it is desired to perform observation with the light transmission optical microscope as described above in the first embodiment, it is only necessary to separate the detection element500from the sample support600and to use only the detection element500. In such a case, it is necessary that the detection element500is as transparent as possible with respect to the light from the light transmission optical microscope used.

Since the light generated in the light-emitting region813is released in the lower direction in the drawing, a light reflective portion815may be provided between the light sample support600and the detection element500to reflect light and generate reflected light816in order to enhance a light detection rate. The light reflective portion815is configured by providing a light reflective film for reflecting light on the lower surface of the detection element500, making the sample support600from metal polished for easily reflecting light, or arranging a metal film for reflecting light between the sample support600and the detection element500. In such a case, it is desirable that the region B is transparent enough to deliver the emitted light while minimizing a loss. A detector instead of the light reflective portion815may also be provided on the lower side of the detection element500separately from the light detector800, the light may be detected by these detectors together, and the detection signals may be synthesized.

According to the scheme of directly detecting the charged particle beam, the position of the detector for detecting the transmitted charged particle beam is limited at least to a position below the sample. However, by transforming the transmission charged particle beam into light and detecting the light as described above, a degree of freedom in relation to the detector installation position significantly increases, and it becomes possible to form a transmission charged particle beam image even from a signal from a detector in the lateral direction of the sample or in the upper direction than the sample. This is because the light generated by the transmission charged particle beam is omnidirectionally generated inside the light-emitting member as described above and the light can be detected regardless of the direction in which the detector is installed with respect to the sample. Specifically, the “lateral direction” of the sample means a position at which a horizontal surface where the sample is placed intersects a detection surface of the detector, and the “upper direction” of the sample means a position when the detection surface of the detector is above (on the side of the charged particle source) the horizontal surface where the sample is placed.

Next, an exemplary apparatus configuration according to the embodiment will be shown inFIG. 21. InFIG. 21, a configuration includes the charged particle optical column2, the case body7, the vacuum pump4, the sample stage5, the control system, and the like in the same manner as inFIG. 17. Since operations and functions of the respective elements and additional elements that are added to the respective elements are substantially the same as those in the first embodiment, detailed descriptions thereof will be omitted. In the case of the embodiment, the detection element500for detecting, as alight signal, the charged particle beam that has been transmitted through or scattered in the sample is arranged below the sample in the same manner as in the first embodiment. The detection element500is a light-emitting member capable of emitting light such as ultraviolet light, visible light, or infrared light when irradiated with the charged particle beam. The signal of the light emitted by the detection element500is detected by the detector3provided in the case body7or the light detector800that is capable of detecting light that has passed the light transmission path801for delivering light to the light detector800. Although two detectors, namely the detector3and the light detector800are illustrated in the drawing, any one of or both the detectors may be provided. In addition, a detector for detecting the charged particle beam and the light may be arranged at another location and may be used to detect the light from the light-emitting member. For example, it is possible to use a detector that is arranged in the charged particle optical column instead of the aforementioned detectors or to use the detector in the charged particle optical column along with the aforementioned detectors. It is possible to obtain an internal transmission signal of the sample by the detector3or the light detector800. Although not shown in the drawing, the light-emitting member500and the sample support or the stage may be fixed to each other by a double-stick tape or the like in order for the light-emitting member500not to drop from the sample support or the stage when the sample stage is moved. In a case in which it is desired to prevent contamination due to contact of the double-stick tape with the light-emitting member from occurring, a component for covering the side surface, the upper surface, or the like of the light-emitting member500may be provided as described above.

Hereinafter, a detailed description will be given of the detector3. The detector3is a detector that is capable of detecting the light signal generated by the detection element500, and for example, is a semiconductor detector that is made of a semiconductor material such as silicon. Since an electron-hole pair is generated when the light signal is incident on the semiconductor detector, the light signal is transformed into an electrical signal. The electrical signal is amplified by a signal amplification circuit53or the like and is displayed on the screen of the computer35as image information via the lower-order control unit37or the upper-order control unit36or is stored in a storage unit such as a memory or a hard disc. The semiconductor detector is configured of silicon or the like, and it is possible to produce the semiconductor detector to have a significantly thin thickness. Therefore, it is possible to arrange the semiconductor detector at a significantly narrow position between the charged particle optical column and the sample. Since resolution of an image increases as the distance between the charged particle optical column and the sample decreases in a case of a typical charged particle beam apparatus, for example, it is desirable to detect light by using the thin semiconductor detector3in a case in which it is desired to narrow the distance between the charged particle optical column and the sample.

Next, a description will be given of the light detector800. The light detector800is a photomultiplier that is capable of transforming and amplifying the light signal into an electrical signal (photomultiplier). The light generated by the detection element500passes through the light transmission path801that can allow passing of the emitted light in the wavelength region and reaches the light detector800such as a light intensifier tube that is provided outside the case body7. A material of the light transmission path801that allows the passing of the emitted light in the wavelength region is a material that is transparent or semi-transparent with respect to the light, such as quartz, glass, optical fiber, or plastic. In order to cause the light to easily reach the light detector800such as a photomultiplier, a light reflective material or the like may be arranged in the circumference of the light transmission path801. The light which has reached the light intensifier tube is amplified and is transformed into an electrical signal. The electrical signal is amplified by the signal amplification circuit802or the like and is displayed on the screen of the computer35as image information via the lower-order control unit37or the upper-order control unit36or is stored in the storage unit such as a memory or a hard disc.

FIG. 22illustrates another configuration of the light transmission path801. InFIG. 22(a), the light transmission path801for delivering light is arranged between the charged particle optical column and the sample in order to efficiently collect the light. More specifically, the light transmission path801is provided immediately below the charged particle optical column, for example, below the field lens. The light transmission path801illustrated in the drawing is an annular light transmission path including a hole803provided at the center thereof so as to allow the primary charged particle beam to pass therethrough. The light transmission path801is provided with a light reflective material804(the one-dotted chain line in the drawing) for delivering the light to the side of the light detector800such as a photomultiplier in order for the light that has once entered the light transmission path801not to leak to the outside. In the case of this configuration, it is possible to collect the light emitted from the detection element500at a wide angle and to thereby more efficiently detect the light. InFIG. 22(b), the light transmission path801for delivering the light is provided immediately next to the detection element. The light transmission path801may be a flexible member such as an optical fiber. Since it is possible to cause the light transmission path801to approach the sample in this example, the light is significantly effectively collected. In addition, since resolution of an image increases as the distance between the charged particle optical column and the sample is shorter in the typical charged particle beam apparatus as described above, the configuration illustrated inFIG. 22(b)is preferably employed in a case in which it is desired to further narrow the distance between the charged particle optical column and the sample.

The light transmission path801may be arranged at a position other than the aforementioned position, and may be arranged on the lower side or the lateral side of the sample stage5, or may be arranged in the charged particle optical column, for example. The light detector800such as a photoelectron amplifier may be inside or outside the case body7as long as the light transmission path801is used, and a degree of freedom in arranging the detector increases. In addition, it is not necessary to provide the light transmission path801as long as it is possible to arrange the light detector800such as a photomultiplier at a location that is relatively close to the sample. Positions and modification examples of the light amplifier and the light transmission paths belong to the scope of the charged particle beam microscope according to the embodiment as long as the light amplifier and the light transmission path satisfy the functions intended in the embodiment.

If the sample6is mounted on a sample support in the related art that does not emit light instead of the detection element500as a light-emitting member, the detector3can obtain the reflected charged particle beam that is reflected by the sample6. That is, it is possible to obtain a sample transmission image if the platform to which the sample is mounted is changed to the light-emitting member, and it is possible to use the same apparatus as a typical charge particle beam apparatus if the platform to which the sample is mounted is changed to a non-light-emitting member. Accordingly, it is possible to easily obtain a transmission charged particle image by an apparatus such as a scanning electron microscope in the related art without performing a complicated operation of changing the apparatus or using an apparatus dedicated for observation with the transmission charged particles, by using the sample support according to the embodiment.

In a case in which the sample support according to the embodiment is used in the apparatus configuration illustrated inFIG. 21, the detector3simultaneously detects the charged particle beam reflected by the sample and the light from the light-emitting member of the sample support as described above. Therefore, in a case in which it is desired to detect only the reflected charged particles by the detection element3, a light absorbing body for causing the surface of the detection element3to reflect or absorb the light so as not to allow the detection element3to detect the light from the light-emitting member of the sample support may be provided. Alternatively, in the case in which the detection element3is a semiconductor detection element, arrangement to control a position of a depletion layer, for example, can be made in order to lower detection sensitivity with respect to the light.

Although the description was given of the apparatus configuration in which the space in the case body7was significantly large with reference toFIG. 21, an apparatus configuration may be implemented based on a side entry scheme in which the sample and the sample support are introduced from a small region in the side surface of the case body7as illustrated inFIG. 23. Since the control system for controlling the respective optical lenses, the detection system for detecting the detection signal, the vacuum pump for exhausting from the inside of the case body7and the charged particle optical column2, and the like are obvious, the descriptions thereof will be omitted. The light emitted from the detection element500below the sample6can be detected by the light detector that is arranged inside the case body7or the like. The light detector for detecting the light emitted from the detection element500may be arranged inside or outside the case body7, on the sample support7or the sample stage5, or at any position in the optical column2in the drawing, and positions and modification examples of the light amplifier and the light transmission path belong to the scope of the charged particle beam microscope according to the embodiment as long as the functions intended in the embodiment are satisfied.

In addition, the observation of the inside of the sample may be performed from various angles while the sample is inclined by providing a mechanism capable of inclining the sample in the sample stage5in the apparatus configuration as illustrated inFIG. 17, 21, or23. Information of an inner structure that is obtained by continuously capturing or continuously observing images while continuously moving inclination of the sample or intermittently moving the inclination of the sample at a specific angle and computing such images by a control unit such as a computer may be saved or displayed as a tomography. The information of the inner structure may be saved in a storage unit such as a hard disc. With such a function, it is possible to recognize a three-dimensional structure inside the sample by observing a fine structure inside the sample from various angles. Alternatively, the tomography observation may be realized by providing, to the charged particle beam optical column2, an optical lens capable of changing an angle at which the sample is irradiated with the charged particle beam from the charged particle beam optical column. Since it is not necessary to provide the sample inclining function to the sample stage5in this case, the apparatus configuration is simplified. In addition, stereoscopic observation of stereoscopically observing the sample may be performed by using the saved or displayed image. During the stereoscopic observation, two images that are captured at different angles may be used, an image obtained by overlapping images with different colors may be used, or a display unit such as a monitor capable of allowing three-dimensional observation may be made to perform three-dimensional display.

Third Embodiment

Description of Basic Apparatus Configuration

In the first embodiment, the usage of the same sample support600with the optical microscope and the charged particle beam microscope that are individually arranged was described. Hereinafter, a description will be given of a composite microscope apparatus configuration in which the optical microscope and the charged particle beam microscope are integrated. Although the light detection element503is arranged immediately below the sample support, the light detection element503may be arranged at any position as long as the light detection element503can detect light as described above.

First, a description will be given of an outline of this configuration with reference toFIG. 24. Since operations and functions of the respective elements and additional elements that are added to the respective elements are substantially the same as those in the first embodiment, detailed descriptions thereof will be omitted.

In this configuration, the optical microscope250is arranged inside the case body7of the charged particle beam microscope apparatus. The optical microscope250forms an optical microscope image with visible light, ultraviolet light, or infrared light in a specific or entire wavelength region that has passed through the transparent member of the aforementioned sample support. The optical microscope250is arranged on the support panel107that supports the sample stage5and has a configuration of performing observation from the lower side of the sample support600. It is necessary to respectively adjust an optical axis200of the charged particle optical column2and the optical axis251of the optical microscope250in order to match the positions of the observation with the charged particle beam microscope and the optical microscope. Therefore, an optical axis adjustment mechanism260capable of changing the position of the optical microscope250is provided. Here, a state where the cover member122is provided with the optical axis adjustment mechanism260is illustrated. The cover member122is provided with an operation unit of the optical axis adjustment mechanism260. The position of the optical microscope250is changed by causing the optical microscope250to slide along an upper or lateral side of a base263such as a guide or a rail by rotating the optical axis adjustment mechanism260, for example. Although only one optical axis adjustment mechanism260is illustrated in the drawing, a plurality of optical axis adjustment mechanisms260may be provided since it is also necessary to move the optical axes in the direction vertical to the paper plane in the drawing.

The optical axis adjustment mechanism260may be provided only in the second case body according to another embodiment though not shown in the drawing. In such a case, the position of the optical microscope250is changed in a state in which the cover member122is drawn out. Since it is possible to adjust the respective optical axes with this configuration, it is possible to observe the sample6with the charged particle optical column2and to observe the same site based on an optical microscope image with the optical microscope250. Since the sample stage5and the optical microscope250are independently arranged as illustrated in the drawing, the position of the optical microscope250is not changed even if the sample stage5is moved.

According to this configuration, the microscope information that has passed through the optical lens of the optical microscope is delivered to a CCD camera254arranged in the case body7. The CCD camera254functions as a signal formation unit that transforms optical information into a digital signal such as electrical information. The image information that is transformed into the electrical information by the CCD camera254is delivered to the control unit or the like via a communication line209or a communication line45and is then displayed on the monitor. It is a matter of course that an imaging device other than the CCD camera may be provided. A wiring connection portion208capable of delivering the signal while establishing atmosphere insulation between the case body7and the outside of the apparatus is arranged in a space from the communication line209or the communication line45. The image capturing unit may perform direct observation using the ocular lens254as illustrated inFIG. 19.

In addition, the light sources of the optical microscope may be provided in the microscope250as illustrated inFIG. 19or may be arranged on the side of the charged particle optical column2.

According to the charged particle beam microscope with this configuration, it is possible to obtain not only a reflected charged particle microscope image by the detector3but also a transmission charged particle beam microscope image by the detection element500. The configuration in which the sample support600according to the embodiment is provided on the sample stage is the same as illustrated inFIG. 17.

FIG. 25(a)illustrates a first configuration of a circumference of the sample support600. In the case of this configuration, the light detector503with the opening portion607provided at the center thereof is arranged. In doing so, it is possible to arrange the field lens252of the optical microscope at a position near the sample support600. By observing at least apart of the sample6on the sample support600through the opening portion, it is possible to perform observation with the optical microscope from the lower side of the drawing. Furthermore, it is possible to transform or amplify the light that is generated by irradiation of the detection element500with the charged particle beam that has been transmitted through the sample6into an electrical signal by the light detector503in the circumference of the opening portion607.

FIG. 25(b)illustrates a second configuration. In such a case, the light detector503is provided on the lateral side of the sample support600, and the light delivered through the inside of the sample support600is detected on the lateral side of the light detector503. Since there is no light detector between the optical microscope and the sample support600as illustrated inFIG. 25(a)in this case, an optical microscope image with a wide field of view is easily obtained. Although not shown in the drawing, processing of reflecting light inside the sample support600may be performed in order to efficiently collect the light on the lateral side of the sample. For example, processing of performing light reflection treatment such as attachment of a reflective material or application of surface roughness to an upper surface, a lower surface, a side surface, or the like of the sample support600is performed. For example, light reflection treatment processing608is performed on the site as represented by the one-dotted chain line inFIG. 25(b). However, it is also necessary to provide an observation site609with no light reflection treatment processing performed thereon, such as a site to be observed with the optical microscope.

With such a configuration, it is possible to obtain the charged particle transmission signal generated by the charged particle beam apparatus and the light transmission signal generated by the optical microscope inside the same apparatus. Furthermore, it is possible to obtain the charged particle beam microscope image and the optical microscope image of the same site of the sample6. By employing this configuration, it is possible to omit time and effort to alternately place the sample support600in the optical microscope250and the charged particle microscope apparatus601as illustrated inFIG. 1and to perform observation with the optical microscope250and the charged particle microscope apparatus601by a single operation.

Furthermore, since the charged particle beam apparatus according to the embodiment is provided with the detector3, it is possible to obtain, by the detector3, the secondary charged particles that are generated or reflected by the sample, to obtain the transmission charged particles that have been transmitted through or scattered in the sample due to the light emitted by the detection element500, and to obtain the optical microscope image by the optical microscope. Since these images can be obtained at the same time, it is possible to switch display of the secondary charged particle image, the transmission charged particle image, and the optical microscope image on the monitor35by using the lower-order control unit37or the like. In addition, it is also possible to display the three types of images at the same time. Although not shown in the drawing, the light transmission path801, the light detector800such as a photoelectron amplifier, and the like may be arranged in the case body7.

Although it is possible to observe the sample6with the optical microscope and the charged particle microscope without moving the sample stage5in the case illustrated inFIG. 24, the circumference of the sample stage has a significantly complicated structure. Thus, a configuration is also applicable in which the optical microscope250and the charged particle optical column2are aligned as illustrated inFIG. 26. The case body7is provided with the charged particle optical column2and the optical microscope250. Since the sample stage5, the vacuum pump, the detector, the display unit for displaying images, and the control system for controlling the optical lens and the like are obvious, depiction thereof is omitted. The light source256for obtaining an optical microscope image may be provided on the upper side or the lower side of the sample support600. However, in the case in which the light source256is provided on the lower side of the sample support, it is necessary that the sample support600is transparent with respect to the light that is generated by the light source256. If the light source256is provided on the upper side, the sample support600is not necessarily transparent. In the case of this configuration, it is possible to obtain the transmission charged particle image of the sample6and to cause the optical microscope250to obtain light information of the sample6by detecting the light emitted from the detection element500by the same apparatus. Since the positional relationship between the charged particle optical column2and the optical microscope250is maintained constant, it is possible to easily shift the transmission charged particle image and the optical microscope image by causing the control unit of the sample stage5or the upper-order control unit to memorize the positional relationship.

Fourth Embodiment

It is also possible to combine an atmospheric pressure charged particle beam microscope apparatus capable of performing observation under the atmospheric pressure and an optical microscope apparatus and to use the sample support according to the embodiment with the composite apparatus. The configuration will be illustrated inFIG. 27. Since these apparatuses basically have apparatus configurations as a combination ofFIGS. 18 and 24, the repeated description of the aforementioned first to third embodiments will be omitted.

The configuration is characterized in that the aforementioned sample support is arranged between the charged particle optical microscope apparatus capable of performing observation under the atmospheric pressure and the optical microscope250under the atmospheric pressure. It is preferable to employ the apparatus configuration according to the embodiment when it is desired to obtain a transmission charged particle microscope image and an optical microscope image of the same site of a sample that contains a large amount of liquid.

Since it is not necessary to maintain the sample space in the highly vacuum state in the apparatus according to the embodiment, it is possible to carry in and out the sample at a significantly high throughput. In addition, it is possible to set a desired gas type and a pressure inside the second case body7as described above and to thereby perform observation with the transmission charged particle microscope and the optical microscope in desired gas.

Fifth Embodiment

In this embodiment, an example in which the second case body121is not provided unlike the aforementioned embodiments will be described. Since configurations of the circumference of the barrier membrane10, the sample stage5, and the circumference of the optical microscope250are substantially the same as those in the aforementioned first to fourth embodiments, differences will be mainly described below.

FIG. 28illustrates an overall configuration of the charged particle microscope according to the embodiment. In the configuration, the charged particle optical column2is fitted into the case body271and is sealed in the vacuum state with the vacuum sealing member123. The case body271is supported by a pillar269. The pillar269is supported by a base270. Although only one pillar269is illustrated in the drawing, it is preferable to provide a plurality of pillars269to support the case body in practice. Since an atmosphere state of the sample6becomes the same as that outside the apparatus with this configuration, it is possible to expose the sample to a state in a completely atmospheric air.

Gas supply from the gas tank103is performed by a gas nozzle272that is directed toward the direction to the vicinity of the sample6. The gas nozzle272is connected to the case body271via a support273, for example. The gas tank103is connected to the gas nozzle272via a coupling portion102. Although the aforementioned configuration is an exemplary configuration, it is possible to eject desired gas to the vicinity of the sample6with this configuration. As a type of the gas, nitrogen, water vapor, helium gas, hydrogen gas, or the like that is lighter than the atmospheric air is employed in order to reduce scattering of the electron beam. The gas can be freely changed by the user. In addition, the gas tank103may be replaced with a vacuum pump in order to perform vacuum drawing between the barrier membrane10and the sample6.

The optical microscope250is arranged immediately below the case body271, that is, the optical microscope250is arranged coaxially with the optical axis of the charged particle optical column. In doing so, it is possible to obtain the charged particle beam microscope image by irradiating the sample6on the sample support600that is arranged on the sample stage5with the charged particle beam that has passed through the barrier membrane10and to obtain the optical microscope image generated by the optical microscope250. Configurations of the optical axis adjustment mechanism260, the optical lens drive mechanism253for driving the inner lens of the optical microscope in the direction of the optical axis251of the optical microscope250, and the like are the same as those described in the aforementioned embodiments.

With the configuration according to the embodiment, it is possible to observe the same site with the charged particle beam microscope and the optical microscope in a state in which the barrier membrane10, the sample6, and the optical microscope250are in a non-contact state.

Since the sample arrangement space is not limited in the case of this configuration, the configuration is useful when the size of the sample support600is significantly large.

Sixth Embodiment

Next, an example will be shown in which an atmospheric pressure charged particle beam microscope apparatus capable of performing observation under the atmospheric pressure and an optical microscope apparatus are combined. In this embodiment, a description will be given of a configuration in which the charged particle optical column2according to the aforementioned embodiment is arranged on the lower side of the barrier membrane10.

FIG. 29illustrates a configuration diagram of the charged particle microscope according to the embodiment. The vacuum pump, the control system, and the like are omitted in the drawing. In addition, it is assumed that the case body7as a vacuum chamber and the charged particle optical column2are supported by a pillar, a support, or the like with respect to the apparatus installation surface. Operations and functions of the respective elements and additional elements that are added to the respective elements are substantially the same as those in the aforementioned embodiments, the detailed descriptions thereof will be omitted.

In order to maintain the sample6that is mounted to the sample support600and the barrier membrane10in the non-contact state, a sample stage5is provided on the barrier membrane holding member or the case body. That is, the lower portion of the sample6in the drawing is irradiated with the charged particle beam. By using the operation unit204for operating the sample stage5, it is possible to cause the lower surface of the sample in the drawing to approach the barrier membrane10or to bring the lower surface thereof into contact with the barrier membrane10.

In addition, the optical microscope602is arranged on the upper side of the charged particle optical column2and the sample support600and is arranged coaxially with the optical axis of the charged particle optical column. In doing so, it is possible to obtain the charged particle beam microscope image by irradiating the sample6that is arranged on the sample stage5with the charged particle beam that has passed through the barrier membrane10and to obtain the optical microscope image generated by the optical microscope602from the upper side in the drawing.

Seventh Embodiment

FIG. 30illustrates a configuration in which the optical microscope is removed from the apparatus according to the fifth embodiment. Since the optical microscope is not provided in the case of the configuration, the opening portion607at the center of the light detector503is not necessarily provided. In a case in which it is desired to perform observation with a separately arranged optical microscope, it is only necessary to remove the sample support501from the sample stage5and to arrange the sample support501in the optical microscope. Since the light is detected in a space outside the apparatus in the case of this configuration, light from the outside, such as room light, is detected by the light detector503in some cases. Therefore, the light from the outside of the apparatus may be blocked by a cover or the like which is not illustrated in the drawing. Although the light detector503is arranged below the sample support501in the drawing, the light detector503may be arranged in the vacuum space11. Since the optical microscope is not provided in the case of this configuration, apparatus cost becomes more reasonable.

Eighth Embodiment

FIG. 31illustrates a configuration in which the optical microscope is removed from the apparatus according to the sixth embodiment. Since the optical microscope is not provided in this configuration, the opening portion607at the center of the light detector503is not necessarily provided.FIG. 31(a)illustrates a state in which the sample6is in close contact with the detection element500. In the case of this configuration, it is possible to move relative positions between the sample6and the barrier membrane10by moving the sample stage5by the drive mechanism204. In addition, the sample6and the barrier membrane10may be brought into contact with each other or may be maintained in a non-contact state. In the case of bringing the sample6into contact with the barrier membrane10, it is only necessary to cover the sample6with the light-emitting member500.FIG. 31(b)illustrates a state in which the sample6is arranged on the barrier membrane10and the detection element500, the light detector503, and the like are provided in a support. Although not shown in the drawing, the detection element500and the light detector503may be provided with drive mechanisms capable of realizing motion in the vertical direction and the horizontal direction in the drawing. It is possible to change the relative positions between the sample6and the optical axis200by the barrier membrane holding member155, the barrier membrane10, and the drive mechanism204that is connected to the sample6mounted to the barrier membrane10. The distance between the sample6and the light-emitting member500is adjusted to a desired distance, and the sample6and the light-emitting member500are arranged via a desired member such as atmospheric gas or desired gas that is introduced from the outside. In doing so, the charged particle beam that has been transmitted through the sample6mounted to the barrier membrane passes through the predetermined distance, and the light-emitting member500is irradiated with the charged particle beam via the gas member of the desired material. Therefore, it is possible to observe the sample6that is mounted to the barrier membrane10with the transmission charged particle microscope. Although not shown in the drawing, the sample6and the light-emitting member500may be in close contact with each other. Since the light is detected in the space outside the apparatus in the case of this configuration, the light such as room light is detected by the light detector503in some cases. Therefore, the light from the outside of the apparatus may be blocked by a cover or the like which is not shown in the drawing. Although the light detector503is above the sample support501in the drawing, the light detector503may be provided inside the vacuum space11. Since the optical microscope is not provided in the case of this configuration as compared with the sixth embodiment, the apparatus cost becomes more reasonable.

The present invention is not limited to the aforementioned embodiments and includes various modification examples. For example, the aforementioned embodiments are for detailed descriptions of the present invention for the purpose of easy understanding, and the present invention is not necessarily limited to a structure including all the aforementioned configurations. It is possible to replace a part of a configuration according to a specific embodiment with a configuration according to another embodiment, or to add a configuration according to another embodiment to a configuration according to a specific embodiment. In relation to a part of a configuration according to each embodiment, addition, deletion, and replacement of another configuration can be made. Moreover, apart or entirety of the aforementioned respective configurations, functions, processing units, processing means, and the like can be realized as hardware by designing the part or the entirety thereof on an integrated circuit, for example. In addition, the aforementioned respective configurations, functions, and the like may be realized as software by a processor interpreting and executing programs for realizing the respective functions.

Information of programs, tables, files, and the like for realizing the respective functions can be stored in a memory, a recording device such as a hard disc or an SSD (Solid State Drive) or a recording medium such as an IC card, an SD card, or an optical disc.

In addition, only the control line and the information line that are considered to be necessary for the description were illustrated, and all the control lines and information lines in a product are not necessarily illustrated. It may be considered that substantially all the configurations are connected to each other in practice.

REFERENCE SIGNS LIST