JP4826632B2 - X-ray microscope and X-ray microscope method - Google Patents

Description

  The present invention relates to an X-ray microscope and a microscopic method based on a scanning transmission electron microscope. The present invention provides a new measurement technique for non-destructively seeing through semiconductor devices, biomaterials, and the like with high spatial resolution at the nanometer level.

References referred to in this specification are as follows. References shall be referenced by their reference numbers.
JP 2004-138461 A JP 2002-202272 A

Many studies and practical devices are commercially available for X-ray microscopes (hereinafter referred to as X-ray microscopes) that have a higher transmission power than electron beams and can obtain transmission images with higher spatial resolution than light. These are roughly divided into two types: (1) scanning transmission type imaging method and (2) projection projection type imaging method.
In the scanning transmission imaging method, an electron beam emitted from an electron source is converged on the order of nanometers by an irradiation electron lens, and this is irradiated to an X-ray target installed in a vacuum. Thereby, X-rays having the same size as the electron beam irradiation size are generated. The generated X-ray passes through the sample immediately below and reaches the X-ray detector. Since X-rays absorb absorption corresponding to the internal composition and density in the sample, a projected image having a contrast corresponding to the internal composition and density can be obtained by imaging the X-ray transmitted through the sample. it can. The basic configuration of this method is disclosed in Patent Document 1. In this method, it is desired to maintain the spatial resolution of the X-ray image by irradiating the sample with X-rays generated from the X-ray target as small as possible, so that the electron beam converges on the X-ray target as small as possible while maintaining a large current. In addition, a device for bringing the X-ray target and the sample as close as possible is effective. Currently, the latter has a spatial resolution determined technically. For this reason, Patent Document 2 discloses an apparatus for mechanically bringing an X-ray target and a sample close to each other. However, in this scanning transmission type imaging method, the members are usually brought close to each other because the processing accuracy of the members determines the limit, and the distance between them is about submicron. In particular, in order to converge the electron beam, it is necessary to insert the sample into a space of several mm between the upper and lower poles, which is called the in-lens system, so that the converging lens approaches the X-ray target and the sample. There was a problem that it was extremely difficult to insert into this space.
On the other hand, in the projection projection type imaging method, the electron beam is irradiated onto the sample in parallel on the surface. X-rays are generated two-dimensionally from the sample when the sample is irradiated with an electron beam. This is applied to the light-receiving surface of a CCD camera or the like using an X-ray lens (generally called a diffraction grating called a Fresnel lens). Form an image. In this method, the spatial resolution is mainly determined by the aberration of the X-ray lens without depending on the irradiation diameter of the electron beam. However, in the projection projection type imaging method, since the X-ray transmittance of the Fresnel lens is low, the sensitivity may not be sufficient. In particular, in imaging of light elements in a sample, since the generated X-ray dose is small, there is a high possibility that S / N (Signal-to-Noise ratio) is not sufficient in the projection projection imaging method.

The present invention provides an X-ray microscope and an X-ray microscope method that improve the spatial resolution and the image S / N, which are the above-mentioned problems, based on the scanning transmission imaging method.
In order to solve the problem, the following means are provided.
1. A thin film serving as an X-ray generation source was formed on the sample surface.
2. Since the sample and the X-ray target are in contact, the sample holder is provided with a temperature adjustment mechanism. That is, in order to obtain a sufficient X-ray dose, it is necessary to irradiate the X-ray target with an electron beam with a large current, and an increase in the sample temperature caused by the electron beam irradiation becomes an inherent problem. For this reason, the sample holder is equipped with a cooling mechanism for cooling the sample by heat conduction from the liquid nitrogen tank and a heating mechanism for preventing dew condensation when the sample is taken in and out.
3. The X-ray target is a thin film, the electron beam is sufficiently stopped, and the X-ray is sufficiently transmitted. For this reason, since the thickness of the thin film depends on the acceleration energy of the electron beam, the optimum thickness is set to twice the range of the electron beam.
4). In the X-ray microscope, X-rays generated at the target are absorbed in the sample, so that an image contrast due to the composition and density difference can be obtained. For example, semiconductor devices are composed of members made of various materials such as silicon, silicon oxide, copper, and tungsten. Since the X-ray absorption rate varies depending on the material, it is desirable that X-rays of various energies can be irradiated to the sample. For this reason, the X-ray target film formed on the sample is assumed to be a multilayer film made of a plurality of materials. In particular, since characteristic X-rays from a material close to the target material have high absorptance, a material having an atomic number within 5 before and after the atomic number of the target sample is targeted.
5). The X-ray target thin film is basically formed on the sample surface by vapor deposition, but in semiconductor device analysis, often only the vicinity of the target transistor is thinned from the wafer backside by a focused ion beam (FIB) apparatus. The observation method is taken. For this reason, also by forming an X-ray target film in the processed groove processed by FIB, rapid evaluation can be performed by suppressing the vapor deposition area of the sample.
In this way, a new measurement technique for non-destructively seeing through semiconductor devices, biomaterials, and the like with high spatial resolution at the nanometer level is provided. Furthermore, according to this method, an enlarged image of the scanning transmission electron microscope can be formed with the portion where the focused crystal plane exists as a bright image and the other portion as a dark image.

FIG. 1 is a configuration example of an X-ray microscope based on an in-lens scanning transmission electron microscope (STEM).
FIG. 2 is a configuration example of an X-ray microscope based on an out-lens scanning electron microscope (SEM).
FIG. 3 is an example of X-ray target thin film formation (surface formation) on a sample.
FIG. 4 is an example of forming an X-ray target thin film on a sample (back surface formation, back surface polishing).
FIG. 5 is an example of forming an X-ray target thin film on a sample (surface formation, surface / back surface polishing).
FIG. 6 is an example of X-ray target thin film formation (multilayer target formation) on a sample.
FIG. 7 is an example of X-ray target thin film formation (surface formation) on a sample.
FIG. 8 shows an example of the configuration of a temperature-adjustable sample stage.

FIG. 1 shows an embodiment of the present invention. Here, an apparatus called a scanning transmission electron microscope (STEM) is usually used as an electron beam apparatus. That is, the primary electron beam 26 radiated from the electron gun 11 is irradiated with an irradiation lens 12, a condenser diaphragm 13, an axis deviation correcting deflector 14, a stigmator 15, an image shift deflector 16, a scanning deflector 17, an objective lens. A sample 24 that is minutely shaped and fixed on the sample stage 20 is focused and irradiated. In the present invention, a thin film serving as an X-ray target is formed directly on the sample 24. For example, in FIG. 1, a vapor deposition film 25 is formed on the sample 24 by vapor deposition, and the primary electron beam 26 first enters the vapor deposition film 25. Accordingly, an X-ray 27 excited by an electron beam is generated immediately above the sample 24, which passes through the sample 24 and enters the CCD camera 34 via the scintillator 33. Here, the CCD camera 34 detects a light image and can form an image even when directly irradiated with X-rays. However, the X-rays have high transmissivity, and in order to match the spectral sensitivity characteristics of the CCD, The scintillator 33 converts X-rays to 500 nm light having high CCD light receiving sensitivity (conversion quantum efficiency). Here, it is effective to use, for example, a YAG single crystal doped with Ce. In FIG. 1, the CCD camera 34 is installed in the atmosphere. That is, the X-ray 27 passes through the vacuum flange 32 with the X-ray window and forms an image on the scintillator 33. However, when the X-ray energy is low, the scintillator 33 and the CCD camera 34 may be placed in a vacuum. The CCD camera 34 is assumed to have a so-called slow scan function of slowing the signal reading speed by being a Peltier element or water-cooled from the viewpoint of increasing sensitivity, that is, improving the image S / N.
Now, since X-rays go straight from the vapor deposition film 25 to the CCD camera 34, the X-ray light source increases in proportion to the distance between the X-ray target (here vapor deposition film 25) and the sample, and the resolution deteriorates. For example, when the distance between the X-ray target and the sample is L and X-rays emitted from the X-ray target at an angle of ± 45 ° are used, the light source diameter d is d = 2L. For this reason, when both are mechanically brought close to each other as in the conventional method, it becomes d to several hundred nm, and the resolution is limited by the distance between the two, no matter how much the electron beam converges in the irradiation system. It becomes. However, in the present invention, since the X-ray target is formed on the sample, the distance between the two can be set to several tens of nanometers, so that high resolution of one digit or more can be realized.
The electron gun 11, the irradiation lens 12, the condenser diaphragm 13, the axis deviation correcting deflector 14, the stigmator 15, the image shift deflector 16, the scanning deflector 17, and the objective lens 18 are an electron gun control circuit 11 'and an irradiation, respectively. Lens control circuit 12 ′, condenser aperture control circuit 13 ′, axis deviation correction deflector control circuit 14 ′, stigmeter control circuit 15 ′, image shift deflector control circuit 16 ′, scanning deflector control circuit 17 ′, It is controlled from the system control / display computer 22 via the objective lens control circuit 18 '. Similarly, the sample stage 20 is controlled from the system control / display computer 22 via the sample stage control circuit 20 ′. For example, in the current scanning transmission electron microscope with an acceleration voltage of 200 kV, an electron beam having a beam diameter of about 0.1 nm can be irradiated onto the sample 24. For example, if the hole diameter of the condenser aperture 13 is increased, the beam diameter is made 1 nm. The current on the sample surface can be increased by several orders of magnitude. In particular, in the case of an X-ray microscope, since the amount of X-ray generation in the sample is small, it is necessary to increase the irradiation current amount as much as possible. Although the aberration correction of the electron optical system is performed by the stigmator 15 or the like, it is also effective to improve the current density while keeping the beam diameter small by installing a spherical aberration lens combined with a multipole lens.
In this embodiment, an X-ray or secondary electron detector 19 is installed in the vicinity of the sample 24. This is because image information is separately required in order to confirm that the beam is correctly focused on the vapor deposition film 25 at the stage before acquiring the X-ray image. Here, when the detector is an X-ray detector, the characteristic X-ray 28 generated in the vapor deposition film 25 or the sample 24 is detected, so that a composition image is obtained. In the case of a secondary electron detector, the surface unevenness image of the deposited film 25 is mainly obtained. In any case, the irradiation condition is optimized while monitoring this, and the primary electron beam 26 having a minute and large current is formed. Similarly, in this embodiment, a transmission electron detector 21 and a scattered electron detector 23 are installed. This is mainly for obtaining a transmission image of the sample 24. That is, information such as the crystal structure of the sample can be obtained from the transmission electron detector 21, and information on the composition structure of the sample can be obtained from the scattered electron detector 23. Can be. The transmission electron detector 21 and the scattered electron detector 23 are controlled by the system control / display computer 22 via the electron detector control circuit 21 ′, and an image is displayed on the system control / display computer 22.

  FIG. 2 shows an embodiment of the present invention. Here, a device called a scanning electron microscope (SEM) is usually used as an electron beam device. That is, the primary electron beam 26 radiated from the electron gun 11 is irradiated with an irradiation lens 12, a condenser diaphragm 13, an axis deviation correcting deflector 14, a stigmator 15, an image shift deflector 16, a scanning deflector 17, an objective lens. A sample 24 that is minutely shaped and fixed on the sample stage 20 is focused and irradiated. In the present invention, a thin film to be an X-ray target is formed directly on the sample 24 as in the first embodiment. The primary electron beam 26 first enters the deposited film 25. Therefore, an X-ray 27 excited by an electron beam is generated immediately above the sample 24, passes through the sample 24, and enters the CCD camera 34 via the scintillator 33. The CCD camera 34 was installed in the atmosphere. That is, the X-ray 27 passes through a vacuum flange 32 with an X-ray window and forms an image on the scintillator 33. Electron gun 11 firing lens 12, condenser aperture 13, axis deviation correcting deflector 14, stigmator 15, image shift deflector 16, scanning deflector 17, and objective lens 18 are electron gun control circuit 11 'and irradiation lens, respectively. Control circuit 12 ', condenser aperture control circuit 13', axis deviation correction deflector control circuit 14 ', stigmeter control circuit 15', image shift deflector control circuit 16 ', scanning deflector control circuit 17', objective It is controlled from the system control / display computer 22 via the lens control circuit 18 '. Similarly, the sample stage 20 is controlled from the system control / display computer 22 via the sample stage control circuit 20 '. In the present embodiment, an X-ray or secondary electron detector 19 is installed near the sample 24, and an E × B deflector 42, a secondary electron or reflected electron detector 31 is installed above. This is also for converging the beam on the vapor deposition film 25 with high accuracy as in the first embodiment. The E × B deflector 42 is controlled by the system control / display computer 22 by the E × B deflector control circuit 42 ′, the secondary electron or reflected electron detector 31 by the secondary electron or reflected electron detector control circuit 31 ′. The

例えば、ターゲット試料がシリコンの場合、Ｅ＝２００ｋＶの電子線の飛程は約２００ミクロンである。一方、シリコンで発生した特性Ｘ線はシリコン中では数ｎｍ透過することから、ターゲット試料厚さは十分に薄いと言える。試料２４電子線照射エネルギーを抑制する観点から裕度を持たせるとして、ここではターゲット試料の厚さは、飛程の０．５倍以上、２倍以下と成るように形成するものとする。ターゲット膜形成は、ターゲット材料を加熱して真空中で飛ばす真空蒸着法のほか、ターゲット材料に電子線を照射することで飛ばす電子線蒸着法、真空中の試料近傍に例えば有機タングステンガスなどを流し、成膜箇所を収束イオンビームで走査することにより有機タングステンガスを分解、金属化して固着させるイオンビームアシストデポジション法など、試料との相性や成膜面積に応じた膜形成法をとるものとする。
図４では、蒸着膜２５を試料２４表面に形成した後、基板側から評価箇所以外の構造物をウェハ裏面から研磨して除去した試料加工の方法を示す。図４（ｂ）では、配線構造の評価に着目し、プラグ・ゲート以下を研磨で除去した。すなわち、蒸着膜２５で発生したＸ線は配線構造のみで吸収の大小による像コントラストが形成されるものとし、プラグ・ゲートや基板での吸収によるコントラスト低下を抑制することを目的としている。
図５では、配線構造を残し、裏面から試料を研磨し、さらに研磨孔部分に裏面からターゲット材料を蒸着する方法を示した。すなわち、基板側に蒸着膜２５が形成される。この試料の場合、電子線入射方向は図中下から上向きとなる。この試料前処理法においては、イオンビームアシストデポジション法が有効である。すなわち、初めはアシストガスを流さず収束イオンビームで目的箇所を研磨し、試料加工が終了し次第ガスを流すことで、連続的にターゲット膜を視野近傍に形成することができるからである。
図６には、ゲート・プラグ構造を評価する場合の試料前処理法を示す。この場合、上部の配線構造と下部の基板構造を収束イオンビームで研磨、除去する。図６（ｂ）では、試料上面からターゲット膜を形成した例が示されているが、基板側の孔にターゲット膜を形成することも可能である。それぞれ、ターゲット面がある側から電子線を照射することとする。このように、Ｘ線は試料中の微小構造物での吸収量が小さいため、できるだけ目的の構造物による像コントラストを上げるためには、前後の余分な構造物を除去すると共に、加工孔にターゲット膜を形成することでターゲット膜と観察対象の距離をできるだけ短くすることが空間分解能の向上のために極めて重要である。
図７には、ターゲット膜を複数多層に形成する実施例を示す。半導体デバイスは複数の材料から形成される。特に酸素、窒素のような軽元素、シリコンや銅のような中重元素、タングステンのような重元素と様々な材料からなる構造物が同一視野内に存在する場合、それぞれの材料の透過能を最大化するエネルギーのＸ線を複数準備することは重要である。一般的には、観察対象の元素に近い原子番号のターゲット材から発生させたＸ線の吸収率が高くなることから、カーボン、アルミニウム、亜鉛、金などをターゲット膜として形成する。ここでは、大電流の電子線を照射することから、融点が高く、電子線による照射ダメージが小さく、照射による脱ガスなどの少ない材料を選択するなどの工夫が必要である。Here, the sample pretreatment will be described with reference to FIGS. 3 to 7 by taking an X-ray microscopic method, in particular, a semiconductor device evaluation as an example. FIG. 3A is a cross-sectional structure diagram of a semiconductor device having a typical structure before pretreatment. That is, there is a plug or gate structure on the silicon substrate, and there is a wiring structure that electrically connects them above. In the drawing, the thick solid line indicates the surface contour of the sample, and the thick dotted line indicates that the structure is connected to an adjacent location via the dotted line. In semiconductor device analysis, it is required to quickly evaluate the wiring below the surface, the disconnection of the plug structure, voids, the presence or absence of an altered layer between plug substrates, and the presence or absence of crystal defects in the substrate. Conventionally, a focused thin-film sample was extracted from a semiconductor wafer using a focused ion beam, and this was observed with high resolution using a transmission electron microscope. However, it took time to extract the sample, and damage to the sample was also caused. Since this is a problem, it has been difficult to apply to the evaluation of a structure that is easily deformed, such as an interlayer film. For this reason, evaluation with a probe having high permeability such as X-rays is required, but as described above, there is a problem that evaluation with high spatial resolution is difficult as with electron beams. For example, with respect to the above-described evaluation problem, a wiring is 100 nm or less (in the case of a void, a 10 nm altered layer or a defect is required to have a resolution of 1 nm. For this reason, by providing an X-ray target film directly on a sample, high resolution is achieved. This has been described in Examples 1 and 2. Corresponding to this, the simplest X-ray target film forming method is shown in Fig. 3. That is, the vapor deposition film 25 is directly formed on the sample 24. The incident direction of X-rays is downward from the top in the figure, whereby X-rays generated in the deposited film 25 are transmitted through the sample 24. At this time, the amount of X-ray absorption varies depending on the composition and density. The composition and density distribution in the sample can be obtained by capturing the X-ray distribution transmitted through the sample in a two-dimensional manner. Unabsorbed thickness A virtual manner. Usually, the accelerating voltage of the electron beam E (KV), the case of the density of the target sample ρ (g / cc), a depth of the electron beam to penetrate, the projected range Rρ (mg / cm ²⁾ is It is given by the following equation (Equation 1).

For example, when the target sample is silicon, the range of the electron beam of E = 200 kV is about 200 microns. On the other hand, since characteristic X-rays generated in silicon transmit several nm in silicon, it can be said that the target sample thickness is sufficiently thin. Assuming a margin from the viewpoint of suppressing the electron beam irradiation energy of the sample 24, here, the thickness of the target sample is formed to be not less than 0.5 times and not more than 2 times the range. Target film formation includes the vacuum evaporation method in which the target material is heated and blown in a vacuum, the electron beam evaporation method in which the target material is blown by irradiating an electron beam, and an organic tungsten gas, for example, is allowed to flow near the sample in the vacuum. The film formation method is based on compatibility with the sample and the film formation area, such as the ion beam assisted deposition method in which the organic tungsten gas is decomposed and metalized by scanning the film formation site with a focused ion beam. To do.
FIG. 4 shows a sample processing method in which after the vapor deposition film 25 is formed on the surface of the sample 24, structures other than the evaluation portion are polished and removed from the back side of the wafer from the substrate side. In FIG. 4B, paying attention to the evaluation of the wiring structure, the plug and the gate and below are removed by polishing. That is, the X-ray generated in the vapor deposition film 25 is intended to form an image contrast due to the magnitude of absorption only by the wiring structure, and to suppress a decrease in contrast due to absorption by the plug / gate or the substrate.
FIG. 5 shows a method of leaving the wiring structure, polishing the sample from the back surface, and further depositing the target material from the back surface to the polishing hole portion. That is, the vapor deposition film 25 is formed on the substrate side. In the case of this sample, the electron beam incident direction is upward from the bottom in the figure. In this sample pretreatment method, an ion beam assisted deposition method is effective. That is, the target film can be continuously formed in the vicinity of the field of view by polishing the target portion with the focused ion beam without flowing the assist gas and then flowing the gas as soon as the sample processing is completed.
FIG. 6 shows a sample pretreatment method for evaluating the gate plug structure. In this case, the upper wiring structure and the lower substrate structure are polished and removed with a focused ion beam. Although FIG. 6B shows an example in which the target film is formed from the upper surface of the sample, the target film can be formed in the hole on the substrate side. In each case, the electron beam is irradiated from the side with the target surface. As described above, since the amount of X-rays absorbed by the minute structures in the sample is small, in order to increase the image contrast by the target structure as much as possible, the excess structures before and after are removed and the target is formed in the processing hole. In order to improve the spatial resolution, it is extremely important to reduce the distance between the target film and the observation target as much as possible by forming the film.
FIG. 7 shows an embodiment in which a plurality of target films are formed in multiple layers. The semiconductor device is formed from a plurality of materials. In particular, when structures with various materials such as light elements such as oxygen and nitrogen, medium heavy elements such as silicon and copper, and heavy elements such as tungsten exist in the same field of view, the permeability of each material can be reduced. It is important to prepare a plurality of X-rays with energy to be maximized. In general, since the absorption rate of X-rays generated from a target material having an atomic number close to the element to be observed is increased, carbon, aluminum, zinc, gold, or the like is formed as a target film. Here, since a high-current electron beam is irradiated, it is necessary to devise a method such as selecting a material having a high melting point, a small irradiation damage due to the electron beam, and less degassing due to irradiation.

In the present invention, since a target film serving as an X-ray source is directly formed on a sample, a problem inherent to the method of increasing the temperature of the sample that has not occurred in the conventional method occurs. That is, in order to generate as many X-rays as possible, it is necessary for the electron beam to irradiate a current of microamperes or more. Depending on the shape of the sample, the temperature rise may reach several hundred degrees. In this case, problems such as deformation, flow, and dissolution of the sample occur. For this reason, the sample stage shown in FIG. 8 was devised. In FIG. 8, the polished sample 24 leaving the wiring structure is fixed on the sample holder 20. The primary electron beam 26 is irradiated from the vapor deposition film 25 side, and the generated X-rays 27 pass through the sample 24 and are projected downward through a hole provided in the sample holder 20 toward the CCD camera 34 (not shown). The The sample holder 20 is in thermal contact with the liquid nitrogen 37 in the liquid nitrogen tank 36 via the cooling rod 38. In order to effectively cool the sample 24, a cooling jig 35 is disposed so as to surround the sample 24. Since the liquid nitrogen 37 and the liquid nitrogen tank 36 need to be installed in the atmosphere, the cooling rod 38 is vacuum-sealed with respect to the electron microscope mirror body 44 through an O-ring. That is, the sample 24 is cooled to liquid nitrogen temperature in a vacuum. On the other hand, when the sample is taken in and out, the sample 24 needs to return to room temperature in order to prevent condensation. For this reason, the heater 39 controlled by the heater control power supply 40 is embedded in the sample holder 20, and the sample temperature is returned from the liquid nitrogen temperature to the room temperature at the time of loading and unloading.
Although the examples of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made and those skilled in the art will understand that the above-described embodiments can be appropriately combined. Let's be done.

  We will provide a new measurement technique that allows non-destructive fluoroscopy of semiconductor devices and biomaterials with high spatial resolution at the nanometer level.

Claims (7)

A sample stage for holding the sample;
An irradiation optical system for focusing and scanning the electron beam on the surface of the sample;
A detector for detecting X-rays transmitted through the sample by scanning the electron beam;
A detector for detecting an electron beam transmitted through the sample by scanning the electron beam;
Means for forming a transmission image of the sample from the signal detected by the detector;
Means for displaying the transmission image ;
A thin film that generates X-rays ,
Wherein the sample, X-ray microscope, characterized in that a sliced sample using samples forming the thin film on the incident side of the electron beam. An X-ray microscope characterized in that the sample stage according to claim 1 is provided with a mechanism for adjusting the temperature of the sample. The mechanism for adjusting the temperature of the sample according to claim 2,
An X-ray microscope comprising: a mechanism for cooling a sample with liquid nitrogen, liquid oxygen, liquid helium, and Peltier element; and a mechanism for heating the sample with a heater. A sample stage having a thickness that allows transmission of an electron beam, and holding a sample on which a thin film for generating X-rays by irradiation of the electron beam is formed;
An irradiation optical system that irradiates and scans the sample with the electron beam;
A transmission electron detector that detects electrons transmitted through the sample by scanning the electron beam;
An X-ray detector for detecting X-rays transmitted through the sample by scanning the electron beam;
Image forming means for forming and displaying a transmission image or X-ray image of the sample from image information of the sample detected by the transmission electron detector or image information of the sample detected by the X-ray detector;
An X-ray microscope comprising: means for controlling an irradiation position of the electron beam for acquiring the X-ray image from image information of the sample detected by the transmission electron detector. The X-ray microscope according to claim 4,
A scattered electron detector for detecting an electron beam scattered from the sample by irradiation of the electron beam;
An X-ray microscope characterized in that a scattered electron image of the sample can be displayed on the image forming means from image information of the sample detected by the scattered electron detector. In the X-ray microscopic method for observing the structure inside the sample,
Exposing the structure and polishing the sample so that an electron beam can pass through the structure;
Forming a thin film that generates X-rays by irradiating the electron beam to the polished portion of the sample,
Irradiating the electron beam to the sample after polishing to form a transmission image of the structure,
Based on the formed transmission image, determine the irradiation position of the electron beam to the structure,
An X-ray microscopic method comprising: detecting an X-ray generated by irradiating the irradiation position with the electron beam and acquiring an X-ray image. A sample stage having a thickness that allows transmission of an electron beam, and holding a sample on which a thin film for generating X-rays by irradiation of the electron beam is formed;
An irradiation optical system that irradiates and scans the sample with the electron beam;
A transmission electron detector that detects electrons transmitted through the sample by scanning the electron beam;
A scattered electron detector for detecting an electron beam scattered from the sample by irradiation of the electron beam;
An X-ray detector for detecting X-rays transmitted through the sample by scanning the electron beam;
From the image information of the sample detected by the transmission electron detector, the image information of the sample detected by the scattered electron detector, or the image information of the sample detected by the X-ray detector, the transmission image of the sample Image forming means for forming and displaying a scattered electron image or an X-ray image;
An X-ray microscope comprising: means for controlling an irradiation position of the electron beam for acquiring the X-ray image from image information of the sample detected by the transmission electron detector or the scattered electron detector.

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