JP6097863B2 - Charged particle beam apparatus, sample image acquisition method, and program recording medium - Google Patents

Description

  The present invention relates to a charged particle beam apparatus capable of observing a sample under atmospheric pressure, a desired gas pressure, or a gas species.

  In order to observe a minute region of an object, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like is used. Generally, in these apparatuses, a housing for placing a sample is evacuated and the sample atmosphere is evacuated to image the sample. However, biochemical samples, liquid samples, and the like are damaged or changed in state by vacuum. On the other hand, since there is a great need to observe such a sample with an electron microscope, an SEM apparatus capable of observing the observation target sample under atmospheric pressure, a desired gas pressure, or a gas species is strongly desired.

  Therefore, in recent years, by providing a diaphragm or minute hole through which the electron beam can pass between the electron optical system and the sample to partition the vacuum state in which the electron beam comes from the sample atmosphere, the atmospheric pressure or the desired gas pressure or An SEM device is disclosed in which a sample can be placed under a gas species. This publicly known document discloses an apparatus capable of performing sample position change and SEM observation under atmospheric pressure in a state where the diaphragm and the sample are not in contact with each other using a sample stage disposed immediately below the diaphragm. Yes.

JP 2012-221766 A

  When the observation target sample atmosphere is under atmospheric pressure, under a desired gas pressure or gas type, there is a problem that the electron beam is scattered by the introduced diaphragm, atmospheric gas, or introduced gas, and the microscope image becomes unclear. . For example, in a device that irradiates a charged particle beam to a sample placed under atmospheric pressure in a state where the diaphragm and the sample are not in contact with each other, the charged particle beam is scattered by gas molecules in the atmosphere if the distance between the diaphragm and the sample is long. The result is an unclear microscopic image. Therefore, it is important to reduce the amount scattered by atmospheric gas molecules by bringing the diaphragm and the sample close to each other.

  However, if the sample and the diaphragm are too close together, the sample and the diaphragm may come into contact with each other and the diaphragm may be damaged.

  Further, Patent Document 1 proposes a method and apparatus for reducing scattering by gas molecules between a diaphragm and a sample by introducing a light element gas. By introducing the light element gas, it is possible to acquire a high-quality image while maintaining the diaphragm and the sample. However, it is necessary for the user to always install a gas cylinder and release gas every time the image is observed. Even if a light element gas is introduced, the electron beam is still scattered. As a result, when observing a sample in a non-vacuum atmosphere with an electron microscope, it is considered common sense that the image quality is extremely deteriorated, and therefore, the scene where such an apparatus can be used effectively is limited.

  In summary, the conventional method has a problem that it is difficult to easily obtain a high-quality image due to the influence of an electron beam scattered by gas molecules and a diaphragm.

  The present invention has been made in view of such problems, and when the atmosphere in the vicinity of the sample to be observed is in a desired non-vacuum state such as in the air, the influence of scattering of the electron beam by the gas or the diaphragm is reduced. It is an object to easily obtain a captured image.

  In order to solve the above problems, the present invention provides a charged particle optical column whose inside is evacuated, a sample stage on which a sample is placed in a non-vacuum space, and a primary charge emitted from the charged particle optical column. A detector for detecting secondary charged particles obtained by irradiating the sample with a particle beam, and a spot of the primary charged particle beam by being scattered before the primary charged particle beam reaches the sample. And a data processing unit for removing the influence on the shape from the signal of the detector.

  According to the present invention, when the atmosphere in the vicinity of the observation target sample is in a desired non-vacuum state such as in the air, a high-quality image can be acquired without using a special gas. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

Mean free process of charged particle beam in atmospheric pressure. Image acquired by charged particle microscope. Principle explanatory drawing. Principle explanatory drawing. The image acquired by the charged particle microscope, and the image after carrying out image processing to the said image. 1 is a configuration diagram of a charged particle microscope according to Embodiment 1. FIG. FIG. 3 is an explanatory diagram of the vicinity of the diaphragm and the sample in Example 1. FIG. 3 is an explanatory diagram of the vicinity of the diaphragm and the sample in Example 1. The operation screen in Example 1. FIG. FIG. 3 is an explanatory diagram of an execution flow in the first embodiment. FIG. 3 is a data transmission / reception explanatory diagram according to the first embodiment. Principle explanatory drawing. The operation screen in Example 1. FIG. The operation screen in Example 1. FIG. FIG. 3 is a configuration diagram of a charged particle microscope of Example 2. FIG. 6 is a configuration diagram of a charged particle microscope of Example 3. FIG. 6 is a configuration diagram of a charged particle microscope of Example 4. Principle explanatory drawing. FIG. 6 is a configuration diagram of a charged particle microscope of Example 5. FIG. 6 is a configuration diagram of a charged particle microscope of Example 5. Principle explanatory drawing. FIG. 6 is a configuration diagram of a charged particle microscope of Example 6. The operation screen in Example 7.

  Each embodiment will be described below with reference to the drawings.

  Hereinafter, a charged particle microscope will be described as an example of the charged particle beam apparatus. However, this is merely an example of the present invention, and the present invention is not limited to the embodiments described below. The present invention can also be applied to a scanning electron microscope, a scanning ion microscope, a scanning transmission electron microscope, a combined device of these and a sample processing device, or an analysis / inspection device to which these are applied.

Further, in this specification, “atmospheric pressure” means an atmospheric atmosphere or a predetermined gas atmosphere, and means a pressure environment of atmospheric pressure or a slight negative pressure state. Specifically, the pressure is about 10 ⁵ Pa (atmospheric pressure) to about 10 ³ Pa.

<Principle explanation>
In a charged particle beam apparatus that can be observed under atmospheric pressure, the sample and the diaphragm must be in close proximity. As a result of our calculations, the relationship between the acceleration voltage of the charged particle beam and the mean free path of the charged particle beam at 1 atm is as shown in FIG. The mean free path is the average value of the distance that can travel without being disturbed by scattering. For example, when the acceleration voltage is 100 kV, the average free process is about 200 μm. As will be described later, there is a non-scattered charged particle beam that flies over the mean free path without being scattered and contributes to the resolution of the microscope image. Therefore, when actually observing a sample in the atmosphere with a charged particle beam microscope, the distance between the diaphragm and the sample may be several to five times as long as the mean free path shown in FIG. I know experimentally. That is, when the acceleration voltage of the charged particle beam is in the range of about 1 kV to 100 kV, the distance between the sample and the diaphragm must be about 1000 μm or less.

  FIG. 2 shows the experimental results of observing an observation sample placed in the atmosphere with a scanning electron microscope. The acceleration voltage is 15 kV, and the distance between the diaphragm and the sample is about 70 μm. The character “9” is made of metal, and the others are samples made of Si. In the figure, the A part and the B part are made of the same material, but the brightness of the image is different. Part B is observed brighter than part A. Also, the area around the character “9” appears blurred. On the other hand, the edge of the character “9” can be identified firmly.

  Generally, in an electron microscope, when a certain point is irradiated with a beam, a signal from a region other than the irradiated region is not detected. On the premise of this, it is common to scan a beam irradiation point on a sample and acquire an image with a field of view sufficiently larger than the size of the beam shape. That is, the luminance value of one point in the acquired image corresponds to the detection amount of secondary charged particles when the beam is irradiated to the place corresponding to the one point on the sample. Therefore, when the sample of FIG. 2 is observed with an electron microscope having a conventional high-vacuum sample chamber, the character “9” is bright and the other portions are dark, and the brightness of the A and B portions is almost the same. Should not change. However, in the case of the SEM image of FIG. 2, the B part is observed brighter than the A part. An image as shown in FIG. 2 is not acquired by a general electron microscope. A signal from other than the B part is detected in a state where the B part is irradiated with the electron beam. When an electron beam is radiated to the area of B part, a signal from other than the B part is detected. Actually, a part of the electron beam is also irradiated to an area other than the B part. Guessed. That is, the size of the beam shape actually irradiated on the sample is close to the size of the field of view. This phenomenon will be discussed below.

  The general components of the charged particle beam apparatus observed at atmospheric pressure will be described with reference to FIG. FIG. 3A is a conceptual diagram showing the configuration of a charged particle microscope. The charged particle optical column 2 provided with the charged particle source 8 is provided with charged particle optical components such as a condenser lens and an objective lens that can generate an electromagnetic field. A space 11 from the charged particle source 8 to the upper surface of the diaphragm 10 in the drawing is a vacuum. A space 12 from the lower surface of the diaphragm 10 to the sample 6 is a non-vacuum space in the atmosphere or a desired gas atmosphere. In the following description, the distance of the non-vacuum space is the length of the path through which the charged particle beam passes through the non-vacuum space unless otherwise specified, and indicates the length in the charged particle beam direction. Usually, since the charged particle beam is irradiated perpendicularly to the diaphragm 10, the distance between the diaphragm and the sample becomes the distance of the non-vacuum space. A simplified description of this configuration is as shown in FIG. When the surface from which the charged particles are emitted is the object surface 8a, the lens 301, the lens 302, and the lens 303 correspond to the focusing lenses 301a, 302a, and 303a that can focus the charged particle beam. On the other hand, the diaphragm 10 part and the non-vacuum atmosphere space 12 can be described as a scattering lens 10a and a scattering lens 12a for scattering charged particle beams, respectively.

  Here, the length of the optical column of the charged particle microscope (the focal position of the objective lens from the charged particle source) is generally about 10 mm to 1000 mm, although it depends on the acceleration voltage. In order to focus the charged particle beam, the length of the optical column generally increases as the acceleration voltage increases. In other words, if the length of the optical barrel is h1, and the distance between the diaphragm and the sample is h2, the following relationship holds.

h1 / h2 ≧ 1000 (Formula 1)
Therefore, the distance h2 between the diaphragm and the sample is actually much smaller than h1 than illustrated in FIG. That is, this configuration is very characteristic in that two very thin scattering lenses are introduced close to each other between the focusing lens 303a and the sample surface 6a.

  The charged particles that have passed through the diaphragm include charged particles scattered by the diaphragm and charged particles that have not been scattered. The amount of scattering of charged particle beams at the diaphragm depends on the material type m, density ρ, and thickness t of the diaphragm 10. The charged particles that have passed through the diaphragm enter the space 12 in a non-vacuum atmosphere. Charged particles incident on the non-vacuum atmosphere space 12 are scattered by the atmospheric gas. Again, there are charged particles that can travel without being scattered. The amount of scattering of charged particle beams in a non-vacuum atmosphere space depends on the distance z (h2 in FIG. 3) from the diaphragm 10 to the sample 6, the gas type a in the non-vacuum atmosphere, and the gas pressure P (or density). Further, the amount of scattering in the diaphragm and non-vacuum atmosphere also depends on the irradiation energy E (also referred to as acceleration voltage) of the charged particle beam. For example, as shown in FIG. 1, it can be said that the higher the accelerating voltage, the larger the mean free path, that is, it becomes difficult to scatter. In summary, when two scattering lenses representing the space between the diaphragm and the non-vacuum atmosphere are expressed by one scattering lens function (or deterioration function) A, the scattering lens function is described below.

A = A (m, ρ, t, a, P, z, E) (Expression 2)
Further, when the charged particle beam shape before passing through the space of the diaphragm and the non-vacuum atmosphere is F, and the charged particle beam shape after passing through the space of the diaphragm and the non-vacuum atmosphere is G, it is described by the following formula. The

G = A (m, ρ, t, a, P, z, E) × F (Formula 3)
In addition, as described above, there are charged particle beams that fly without being scattered even by a diaphragm or a non-vacuum atmosphere even through a scattering lens function. In order to explain the situation, scattering of charged particle beams in the diaphragm 10a and the space 12a in a non-vacuum atmosphere will be described with reference to FIG. A beam 305 represents the shape of the beam immediately before entering the diaphragm 10a. Thereafter, when passing through the diaphragm 10a, many charged particles are scattered in the diaphragm and in a non-vacuum atmosphere. On the other hand, there are charged particles that can travel without being scattered. Hereinafter, charged particles that can travel without being scattered by the gas in the diaphragm and non-vacuum atmosphere are referred to as “non-scattered charged particles”, and charged particles that have been scattered one or more times are referred to as “scattered charged particles”. As a result of the scattering of the beam in this way, the beam shape when it reaches the sample 6 becomes 306. In this figure, the horizontal direction is the distance indicating the beam shape (that is, the spatial distance on the sample surface), and the vertical direction represents the number of charged particles. The beam 306 includes a beam 307 composed of non-scattered charged particles and a beam 308 composed of scattered charged particles.

  FIG. 4B shows only the beam shape in an enlarged manner. When the number of non-scattered charged particles is represented by N0 and the number of scattered charged particles is represented by N1, the number of non-scattered charged particles N0 corresponds to a portion (area) 307a inside the beam shape, and the number N1 of scattered charged particles is 308a inside the beam shape. Corresponds to the area (area). That is, in the charged particle microscope apparatus in which the sample 6 is disposed in the atmosphere, the beam 305 focused by the optical lens has a shape represented by the beam 306 immediately before reaching the sample. When the beam diameter of the incident charged particle beam is d0, the beam diameter of the non-scattered charged particle is d1, and the beam diameter of the scattered charged particle is d2, these relations are as follows.

d2> d0 to d1 (Formula 4)
Since the beam diameter d0 of the incident charged particle beam and the beam diameter d1 of the non-scattered charged particles are substantially equal, the resolution of the acquired microscope image is determined by the beam diameter d1 of the non-scattered charged particles. That is, if only the beam 307 remains, the resolution can be maintained if there is a sufficient number of non-scattered charged particles if expressed in another way. Note that the beam diameters represented by d0, d1, and d2 may be specifically defined by a beam diameter, a radius, a half width, or the like as long as the definition of the beam diameter is the same. Hereinafter, unless otherwise specified, the beam shape or spot shape refers to a parameter representing the size of the beam diameter.

  Next, the size of d1 and d2 will be discussed. The beam diameter (d1) of the charged particle beam is generally about 1 nm to 100 nm at maximum. In addition, the material of the diaphragm, thickness, and scattering by gas depend on parameters such as distance, but typically the beam diameter (d2) of the scattered charged particle beam is about 10 nm to 10,000 nm. Since the amount of scattering increases as the distance Z between the diaphragm and the sample increases, d2 may be greater than 10,000 nm. From the above, it can be said that the following formula holds in the case where scattering of charged particle beams is a problem.

d2 / d1 ≧ 10 (Formula 5)
Based on the above consideration, the electron microscope image acquired in FIG. 2 can be explained by the scattered charged particles described in FIG. That is, it can be considered that when the electron beam is irradiated on the portion B in FIG. 2, the beam 308 of scattered electrons is also irradiated on the character “9” portion. On the other hand, since the A part is far from the character “9”, the beam 308 is not irradiated to the part of the character “9” when the A part is irradiated with the electron beam, and is observed darker than the B part. The On the other hand, since the resolution is maintained by the beam 307 of non-scattered electrons, it can be considered that the edge of the character “9” is clearly observed.

  This phenomenon is caused by the fact that the beam diameter of the scattered charged particle beam becomes very large compared to the beam diameter of the non-scattered charged particle beam as expressed by (Equation 5). As a result, the scattered charged particle beam is irradiated over a wide range on the sample. The effect of scattering of charged particles in such a wide range is a characteristic phenomenon when a charged particle beam is irradiated to a sample in a non-vacuum environment, and does not occur in an electron microscope having a conventional vacuum sample chamber. It is a phenomenon.

  From the above phenomenon and consideration, although the diaphragm and the non-vacuum atmosphere represented by a very thin scattering lens arranged between the charged particle optical column 2 and the sample 6 cause the spot shape change of the primary charged particle beam, We have found that image resolution is maintained if unscattered charged particle beam 307 remains. Further, as shown in (Equation 1), the causes of beam scattering are spatially very condensed, so that the beam shape change generated in this space can be theoretically calculated. That is, it is very easy to calculate the scattered beam function G by obtaining the scattering lens function A shown in (Equation 2) from calculation or simulation. This can be said to be a very important configuration from the viewpoint of image restoration described later.

<Image restoration>
The image restoration described below is a process for restoring resolution and image quality degradation by performing some arithmetic processing on the acquired image. In addition, the image restoration described below is not only for performing restoration processing by performing arithmetic processing on the acquired image, but by performing arithmetic processing on the signal output from the detector and generating an image by the processed signal. Including the case of doing.

  In an electron microscope for observing a sample under vacuum, a technique for restoring an image using a beam shape experimentally grasped is conventionally known. For example, a model of the acquired image G is shown below when convolution with a degradation function A such as degradation of resolution and noise n are superimposed on an ideal image F having no noise or resolution degradation.

G = A · F + n (Formula 6)
From this relationship, the ideal image F is estimated from the acquired image G and the deterioration function A. This is called image restoration. This correspondence is equivalent to (Equation 3). That is, it is possible to perform image restoration by obtaining a degradation function A representing the degradation of the beam shape and performing a deconvolution process on the shape. However, until now, it has not been carried out to estimate the ideal image F from the shape of a beam scattered under an air atmosphere, a desired gas pressure or a gas species. This is probably because the scattered region could not be controlled. On the other hand, as described above, in the case of an electron microscope that can be observed at atmospheric pressure, the image quality degradation factor can be regarded as a very thin scattering lens, and the factor that determines the degree of beam shape degradation is from the diaphragm to the sample. It is condensed in a local space. As a result, the only parameter that determines the scattering lens function that determines the beam shape is the parameter resulting from the space between the diaphragm and the non-vacuum atmosphere, and these are controllable, so that the degradation function A required for image restoration is obtained. It becomes very easy. This is one of the important points in the present invention.

  Among the parameters of the scattering lens function A (deterioration function A), the diaphragm used in the apparatus is known, so the material type M, density ρ, and thickness t of the diaphragm 10 are known. That is, the amount of scattering scattered by the diaphragm can be calculated in advance. Further, as will be described later, the acceleration voltage of the charged particle beam, the gas type in the non-vacuum atmosphere, the pressure, and the distance of the non-vacuum atmosphere space can be known by designating the user of the apparatus. That is, from these observation conditions, the ratio of the number of non-scattered charged particles N0 to the number of scattered charged particles N1, the beam diameter d1 of the non-scattered charged particles, the value of the beam diameter d2 of the scattered charged particles, the beam shape, and the like are obtained in advance. It is possible. As a result, it is possible to leave only the beam 307a of non-scattered charged particles and remove the influence of the beam 308a of scattered charged particles from the image signal. Thus, as will be described later, it is possible to estimate the ideal image F from the beam shape scattered under an air atmosphere that has not been carried out until now, or an atmosphere of a desired gas pressure or gas type, and to restore the image. became. Here, “removal” includes not only the case of complete removal, but also the case of partially removing the influence of scattered charged particles and reducing the influence on the image due to beam deterioration.

  The beam shape to be subjected to the image restoration processing is a shape 306 as shown in FIG. Therefore, as a model of the scattering lens function A in (Equation 6), for example, the sum of the first waveform 307a configured with the width d1 and the second waveform 308b configured with the width d2 as shown in FIG. May be used. The first waveform 307a represents the spot shape of the non-scattered charged particle beam, and the second waveform 308b represents the spot shape of the scattered charged particle beam. Since the scattered charged particle beam may be scattered again, it may not be described simply by the sum of two waveform distributions. In that case, the beam shape may be created as the sum of a plurality of waveforms such as d1, d2, d3... Dn while maintaining the condition that the number of incident electrons N is constant. The above-mentioned waveform is, for example, a Gaussian distribution, but may be expressed by any sum of waveforms. When the model of the scattering lens function A is determined, the scattering lens function A can be determined based on the parameters m, ρ, t, a, P, z, and E described in (Expression 2). By performing deconvolution processing on the acquired image G using the determined scattering lens function A, the ideal image F can be restored.

  One of the important points of the present invention is that it is separated into two (or two or more) waveforms of non-scattered charged particles and scattered charged particles, and when performing arithmetic processing for image restoration, It is a point that it was found that a beam shape deteriorated when reaching the sample (that is, a model of a scattering lens function) can be created by adding waveforms representing unscattered charged particles and scattered charged particles.

  In FIG. 5, the images before and after the image restoration process described above are compared. FIG. 5A is before image restoration, and FIG. 5B is after image restoration. FIG. 5 shows the result of the deconvolution processing as described above using the sum of the non-scattered charged particle beam and the scattered charged particle beam as a model of the scattering lens function A under the observation condition satisfying (Equation 5). This is a result of restoring the acquired image shown. It was confirmed that the blurring of the brightness around the character “9” due to scattered electrons can be greatly reduced by restoring the image. Also, the edge of the character “9” can be observed firmly.

  In this image restoration, it is important to grasp the parameters of the scattering lens function and perform image restoration processing. Therefore, hereinafter, a charged particle beam apparatus and an image processing method for restoring an image based on the parameters of the above-described scattering lens function will be described. As will be described later, the ratio of the number of non-scattered charged particles N0 to the number of scattered charged particles N1 according to the acceleration voltage of the charged particle beam, the gas type and pressure of the non-vacuum atmosphere, and the distance of the non-vacuum atmosphere space, The user may input values of the beam diameter d1 of the scattered charged particles and the beam diameter d2 of the scattered charged particles. In addition, the influence of scattering is calculated in advance and the shape of the beam 306 when it reaches the sample is stored in the storage unit in the computer, and the signal acquired by the detector is stored in the storage unit. The image may be automatically restored by performing the deconvolution process using the stored data.

  The image restoration method based on the scattering lens function described above is very effective for an apparatus having a charged particle optical system in which an object that can be regarded as a scattering lens is locally condensed and arranged. Specific embodiments of such an apparatus are shown in the following examples, but the application of the present invention is not limited to the following examples.

<Basic device configuration explanation>
In this example, a basic embodiment will be described. In FIG. 6, the whole block diagram of the charged particle microscope of a present Example is shown.

  The charged particle microscope shown in FIG. 6 mainly includes a charged particle optical column 2, a case (vacuum chamber) 7 connected to and supported by the charged particle optical column 2, and a sample stage 5 disposed in an air atmosphere. And a control system for controlling them. When the charged particle microscope is used, the inside of the charged particle optical column 2 and the housing 7 is evacuated by the vacuum pump 4. The start / stop operation of the vacuum pump 4 is also controlled by the control system. Although only one vacuum pump 4 is shown in the figure, two or more vacuum pumps may be provided. It is assumed that the charged particle optical column 2 and the housing 7 are supported by a pillar or a base (not shown).

  The charged particle optical column 2 includes an element such as a charged particle source 8 that generates a charged particle beam, an optical lens 1 that focuses the generated charged particle beam and guides it to the lower part of the column and scans the sample 6 as a primary charged particle beam. Consists of. The charged particle optical column 2 is installed so as to protrude into the housing 7 and is fixed to the housing 7 via a vacuum sealing member 123. A detector 3 for detecting secondary charged particles (secondary electrons or reflected electrons) obtained by irradiation with the primary charged particle beam is disposed at the end of the charged particle optical column 2. The detector 3 may be outside or inside the charged particle optical column 2. In addition to this, the charged particle optical column may include other lenses, electrodes, and detectors, or some of them may be different from the above, and the configuration of the charged particle optical system included in the charged particle optical column Is not limited to this.

  The charged particle microscope of the present embodiment includes, as a control system, a computer 35 used by the user of the apparatus, and a control unit 36 that controls the evacuation system, the charged particle optical system, and the like according to instructions connected to the computer 35 and transmitted / received. . The computer 35 includes a monitor 33 on which an operation screen (GUI) of the apparatus is displayed, and input means for an operation screen such as a keyboard and a mouse. The control unit 36 and the computer 35 are each connected by a communication line.

  The control unit 36 is a part that transmits and receives control signals for controlling the vacuum pump 4, the charged particle source 8, the optical lens 1, and the like, and further converts the output signal of the detector 3 into a digital image signal to convert the computer 35. And displayed on the screen 33. The image generated by the control unit 36 is displayed on the monitor 33 of the computer 35. In the figure, the output signal from the detector 3 is connected to the control unit 36 via an amplifier 154 such as a preamplifier. If an amplifier is not necessary, it may not be necessary.

  The control unit 36 may be a mixture of analog circuits, digital circuits, or the like, or may be composed of two or more control units. In addition to this, the charged particle microscope may include a control unit that controls the operation of each part. The control unit 36 may be configured as hardware by a dedicated circuit board, or may be configured by software executed by the computer 35. When configured by hardware, it can be realized by integrating a plurality of arithmetic units for executing processing on a wiring board or in a semiconductor chip or package. When configured by software, it can be realized by mounting a high-speed general-purpose CPU on a computer and executing a program for executing desired arithmetic processing. The configuration of the control system shown in FIG. 6 is merely an example, and modifications of the control unit, the valve, the vacuum pump, the communication wiring, and the like can be applied to the SEM of this embodiment as long as the functions intended in this embodiment are satisfied. It belongs to the category of charged particle beam equipment.

  A vacuum pipe 16 having one end connected to the vacuum pump 4 is connected to the housing 7 so that the inside can be maintained in a vacuum state. At the same time, a leak valve 14 for opening the inside of the housing to the atmosphere is provided, and the inside of the housing 7 can be opened to the atmosphere during maintenance. The leak valve 14 may not be provided, and may be two or more. Further, the arrangement location of the leak valve 14 in the housing 7 is not limited to the location shown in FIG. 6, and may be arranged at another position on the housing 7.

  A diaphragm 10 is provided on the lower surface of the housing at a position immediately below the charged particle optical column 2. The diaphragm 10 can transmit or pass the primary charged particle beam emitted from the lower end of the charged particle optical column 2, and the primary charged particle beam finally passes through the diaphragm 10 and finally reaches the sample stage 52. The sample 6 mounted is reached. The closed space formed by the diaphragm 10 (that is, inside the charged particle optical column 2 and the housing 7) can be evacuated. Since the sample is disposed in the non-vacuum space, the diaphragm 10 needs to be able to maintain the differential pressure between the vacuum space and the non-vacuum space. In this embodiment, the airtight state of the space evacuated by the diaphragm 10 is maintained, so that the charged particle optical column 2 can be maintained in a vacuum state and the sample 6 can be observed while maintaining the atmospheric pressure. Further, even when the charged particle beam is irradiated, the space in which the sample is installed is an air atmosphere or communicates with the space in the air atmosphere, so that the sample 6 can be freely exchanged during observation.

  The diaphragm 10 is formed or deposited on the base 9. The diaphragm 10 is a carbon material, an organic material, a metal material, silicon nitride, silicon carbide, silicon oxide, or the like. The base 9 is a member such as silicon or a metal member. Multiple portions of the diaphragm 10 may be arranged. The thickness of the diaphragm capable of transmitting or passing the primary charged particle beam is about several nm to several μm. The diaphragm must not break under the differential pressure to separate atmospheric pressure and vacuum. Therefore, the area of the diaphragm 10 is about several tens μm to at most several mm. The shape of the diaphragm 10 is not square but may be a rectangle or the like. Any shape may be used. If the base for manufacturing the diaphragm 10 is silicon, and the diaphragm material is formed on the silicon and then processed by wet etching, the upper and lower areas of the diaphragm are different as shown in the figure. That is, the upper opening area of the base 9 in the drawing is larger than the diaphragm area.

  A base 9 that supports the diaphragm 10 is provided on the diaphragm holding member 155. Although not shown, it is assumed that the base 9 and the diaphragm holding member 155 are bonded by an O-ring, packing, adhesive, double-sided tape or the like that can be vacuum-sealed. The diaphragm holding member 155 is detachably fixed to the lower surface side of the housing 7 via a vacuum sealing member 124. The diaphragm 10 is very thin with a thickness of about several nm to several μm or less because of the requirement for transmission of the charged particle beam, so that it may be deteriorated with time or damaged during observation preparation. Moreover, since the diaphragm 10 and the base 9 which supports it are small, it is very difficult to handle directly. Therefore, as in the present embodiment, the diaphragm 10 and the base 9 are integrated with the diaphragm holding member 155 so that the base 9 can be handled not via the direct but via the diaphragm holding member 155. Handling (especially exchange) becomes very easy. That is, when the diaphragm 10 is damaged, the diaphragm holding member 155 may be replaced. Even if the diaphragm 10 has to be replaced directly, the diaphragm holding member 155 can be taken out of the apparatus, and the base 9 integrated with the diaphragm 10 can be replaced outside the apparatus.

  Although not shown, an optical microscope capable of observing the sample may be disposed immediately below or near the sample 6. In this case, the diaphragm 10 is on the upper side of the sample, and the optical microscope is observed from the lower side of the sample. Therefore, in this case, the sample stage 52 needs to be transparent to the light of the optical microscope. Examples of the transparent member include transparent glass, transparent plastic, and transparent crystal. As a more general sample table, there is a transparent sample table such as a slide glass (or a preparation) or a dish (or a petri dish).

  Moreover, you may provide the voltage application part etc. which can generate | occur | produce an electric field in a temperature heater or a sample. In this case, it is possible to observe how the sample is heated or cooled and how the electric field is applied to the sample.

  Two or more diaphragms may be arranged. For example, there may be a diaphragm inside the charged particle optical column 2. Alternatively, a second diaphragm may be provided below the first diaphragm that separates the vacuum and the atmosphere, and a sample may be included between the second diaphragm and the sample stage.

  As another embodiment, the sample may be placed in an environmental cell and placed on a sample stage of a normal high vacuum charged particle microscope for observation. The environmental cell is a container that locally maintains the atmosphere in the vicinity of the sample in the vacuum chamber by enclosing the entire sample in a sealed state and introducing the sample into the vacuum apparatus. A sample height adjusting mechanism may be provided inside the environmental cell. The above-described image restoration processing is also effective when removing scattering between the diaphragm provided for the environmental cell and the sample for separating the local atmosphere. The present invention belongs to the category of SEM or charged particle beam apparatus of this embodiment as long as the function intended by this embodiment is satisfied, regardless of the number and type of diaphragms.

  Although not shown, a detector capable of detecting a charged particle beam that has passed through the sample 6 may be disposed immediately below the sample 6. This detector is a detection element that can detect and amplify a charged particle beam that comes in with energy of several keV to several tens of keV. For example, a semiconductor detector made of a semiconductor material such as silicon, a scintillator capable of converting a charged particle signal into light on or inside a glass surface, a luminescent light emitting material, a YAG (yttrium aluminum garnet) element, etc. Is used. An electrical signal or an optical signal from the detector is transmitted to a control system including the upper control unit 36 and the lower control unit 37 via a wiring, a light transmission path, or a photodetector. A transmitted charged particle signal can be detected from a detector on which such a sample is directly or indirectly mounted. Therefore, it is possible to acquire a transmitted charged particle beam image of the sample 6 in the atmosphere by bringing the detector on which the sample 6 is mounted close to the diaphragm 10. Also in this case, the image restoration method in this embodiment is effective.

  A sample stage 5 disposed in an air atmosphere is provided below the diaphragm 10 provided in the housing 7. As a result, the sample is placed in an air atmosphere (non-vacuum space). The sample stage 5 is provided with a Z-axis drive mechanism having a height adjusting function capable of causing at least the sample 6 to approach the diaphragm 10. As a matter of course, an XY drive mechanism that moves in the sample plane direction may be provided. Although not shown in the drawing, as a mechanism for adjusting the distance between the sample 6 and the diaphragm 10, the diaphragm 10 and the diaphragm holding member 155 are arranged in the sample direction (see FIG. 9) instead of or in addition to the Z-axis drive mechanism that moves the sample 6. You may provide the drive mechanism driven to a middle up-down direction). Alternatively, the charged particle optical column 2 and the vacuum casing 7 may be provided with a drive mechanism that can move in the vertical direction, and the entire charged particle optical column 2 and the vacuum casing 7 may be moved to the sample side. These mechanisms that make the distance between the diaphragm and the sample variable by making the diaphragm, sample, or charged particle optical column movable are collectively referred to as a distance adjusting mechanism.

  In this embodiment, the energy E when the charged particle beam from the charged particle beam source 8 reaches the sample is set and controlled. An irradiation energy control unit 59 is provided between the control unit 36 and the charged particle optical column 2. The irradiation energy control unit 59 is a high voltage power source that can change the irradiation energy E of the charged particle beam to the sample by making the voltage supplied to the charged particle beam source 8 variable, for example. The irradiation energy control unit 59 may be inside the control unit 36. As another example, the irradiation energy control unit 59 may be an electrode that changes an acceleration voltage of a charged particle beam from a charged particle beam source. Further, a power source that variably controls the voltage to the optical lens capable of accelerating or decelerating the primary charged particle beam may be used. As another example, a power source capable of applying a voltage to the sample stage may be used. Such a control system may be in the control unit 36 or between the control unit 36 and the optical lens 1. The specific examples of the charged particle beam irradiation energy control unit described above may be used in appropriate combination.

  The computer 35 includes a data transmission / reception unit 60, a data memory unit 61, an external interface 62, and a data processing unit 63. The data transmitter / receiver 60 transmits and receives various data such as reception of detection signals. The data memory unit 61 can store image signals. The external interface 62 is connected to the monitor 33 and the user interface 34 such as a keyboard and a mouse. The data processing unit 63 converts the detection signal into an image signal and outputs it. Furthermore, in the present embodiment, the data processing unit 63 performs a process for removing the influence on the spot shape caused by scattering of the primary charged particle beam before reaching the sample as described above, that is, an image restoration process. In this embodiment, the primary charged particle beam is scattered by the diaphragm and the atmosphere between the diaphragm and the sample. The parameters of the scattering lens function for image restoration can be input by the user interface 34. The data processing unit 63 obtains a beam shape composed of non-scattered charged particles and scattered charged particles using the parameters of the scattering lens function. As described above, the amount of scattering by the diaphragm can be determined by the diaphragm and the material type, density, and thickness. The amount of scattering by the atmosphere between the diaphragm and the sample is the distance between the diaphragm and the sample, the gas type in the atmosphere, and the pressure. Can be obtained. Based on the amount of scattering determined in this way, it is possible to determine the effect that occurs on the spot shape of the primary charged particle beam. Thereafter, the image restoration process is performed on the acquired image or the currently acquired image signal as described above to remove the influence of the scattering on the spot shape. As a result, a microscope image in which the influence of the scattered charged particles is reduced can be displayed on the monitor 33. If the scattering lens function parameters are known and need not be input, the beam shape may be obtained using the correspondence relationship between the image acquisition conditions stored in advance and the scattering lens function parameters. Specifically, a correspondence table between the image acquisition conditions and the scattering lens function parameters is stored in the data memory unit 61, and after the image acquisition conditions are automatically read, the scatter corresponding to the image acquisition conditions using this correspondence table. The lens function parameters are automatically read to determine the scattering lens function, and the image is restored using this function.

  In the apparatus configuration shown in FIG. 6, if the same type of diaphragm is used every time, the material type M, density ρ, and thickness t of the diaphragm 10 are constant without being changed. Further, the gas type A and pressure P in the non-vacuum space (atmospheric space) are almost constant as long as they are used under atmospheric pressure. That is, in FIG. 6, the only factor that fluctuates the scattering lens function parameter is the distance Z between the diaphragm 10 and the sample 6 in this embodiment. Therefore, a plurality of methods for determining the distance between the diaphragm and the sample will be described below.

  In FIG. 7A, only the diaphragm and the periphery of the sample are shown. In this embodiment, a distance control member 400 is provided between the sample 6 and the diaphragm 10. The distance control member is provided so as to protrude from the sample stage, and the tip of the distance control member 400 is always disposed on the diaphragm side of the sample 6 as shown in FIG. Then, as shown in FIG. 7B, the distance control member 400 contacts the diaphragm holding member 155 in the state where the position of the sample table 401 is approached in the direction of the diaphragm 10. As a result, the distance between the diaphragm 10 and the sample 6 can be set to a certain constant value. On the other hand, the height B of the sample 6 may vary depending on the sample. Therefore, it is desirable to have an adjustment mechanism that can adjust the height A of the distance control member 400 according to the height of the sample B. For example, the distance control member 400 is a male screw, and the height A of the distance control member 400 can be changed by turning the screw portion of the distance control member 400 by setting the sample stage 401 side to the female screw 402. Become. The adjustment mechanism may be any mechanism that can move the position where the sample and the diaphragm contact each other in the distance control member 400 in the optical axis direction of the charged particle optical column.

  When the distance (sample thickness) from the sample stage 401 to the sample surface is B and the distance between the diaphragm holding member 155 and the diaphragm 10 is C, the diaphragm when the distance control member 400 is brought into contact with the diaphragm holding member 155 And the distance Z between the samples is given by the following equation.

Z = (A−B) −C (Expression 7)
As described above, the distance Z between the diaphragm and the sample is desirably short from the viewpoint of the mean free path of the charged particle beam. Specifically, it is good that it is 1000 μm or less. Further, in order to prevent the diaphragm 10 and the sample 6 from contacting each other, it is necessary to follow the following formula.

A-B> C (Formula 8)
From the above relational expression, when the distance control member is used, it can be assured that the distance between the sample and the diaphragm is Z.

  Next, another embodiment in which the distance control member 408 is arranged will be described with reference to FIG. In this case, a distance control member 408 is provided on the base 9 holding the diaphragm 10. The distance control member 408 may be a thin film formed on the base 9 in advance, or may be a spacer attached later. For example, when the sample 6 is brought into contact with the distance control member 408 having a known thickness, the distance Z to the diaphragm can be grasped. Alternatively, after the contact, the distance between the sample 6 and the diaphragm 10 can be controlled by separating the sample and the distance control member 408 by a certain known distance again.

  Although not shown, the distance may be grasped by a camera or the like from the lateral direction of the apparatus of FIG. Alternatively, the distance between the diaphragm and the sample may be measured with a laser or the like. Alternatively, the distance between the sample and the diaphragm may be controlled by sending a signal from the data transmitting / receiving unit 400 to a drive control unit (not shown) to electrically drive the sample stage or the like. Although not shown, instead of bringing the sample 6 and the diaphragm 10 closer by moving the sample stage 5 on which the sample 6 is placed, the sample is driven by a driving mechanism in which the diaphragm 10 and the diaphragm holding member 155 are driven in the vertical direction in the figure. 6 and the diaphragm 10 may be brought close to each other. Alternatively, if the sample height is known by measuring the height of the sample 6 at a place other than the charged particle beam apparatus, the diaphragm 10 can be determined from the height of the sample stage 5 without using the method described above. And the distance between the sample 6 can be grasped.

<Operation screen>
FIG. 9 shows an example of the operation screen. Here, an example of image restoration using parameters input through the operation screen will be described.

  The operation screen 700 includes a condition setting unit 701 that sets an observation condition, an image display unit 702 that displays an acquired original image, an image display unit 703 that displays an image after image restoration, an image adjustment unit 704, and an image restoration parameter setting unit. 705 and the like. The condition setting unit 701 includes an irradiation energy E setting unit 706, an irradiation start button 707, an irradiation stop button 708, an image save button 709, an image read button 710, and the like. The image display unit 702 displays an image before image restoration, and the image display unit 703 displays the restored image. The image adjustment unit 704 includes a focus adjustment unit 715, a brightness adjustment unit 716, a contrast adjustment unit 717, and the like.

  The image restoration parameter setting unit 705 is an input field for inputting parameters related to a substance that contributes to scattering of the primary charged particle beam. Specifically, a diaphragm-sample distance setting unit 711, an acceleration voltage input unit 723 for inputting an acceleration voltage at the time of image acquisition, a magnification setting unit 732, an image restoration start button 713, and adjusting the brightness and contrast of the restored image It has a button to do. Here, assuming that the information about the diaphragm is known and the space between the diaphragm and the sample is the atmosphere, the distance Z between the diaphragm and the sample, the acceleration voltage E, and the magnification are set as shown in FIG. The scattered charged particle beam shape can be calculated. As a matter of course, not only the distance Z between the diaphragm and the sample but also other parameters described above may be input as parameters related to the substance contributing to the scattering of the primary charged particle beam. Note that the magnification is set because the size (pixel size) of one pixel constituting an image determines some. The pixel size may be input instead of the magnification.

  From these values, the beam diameter d1 of the non-scattered charged particle beam, the beam diameter d2 of the scattered charged particle beam, and the non-scattered charged particle ratio N0 / (N0 + N1) are determined. These are automatically calculated by preparing calculation formulas and calculation tables in advance as described above and using known parameters stored in the computer. By performing deconvolution processing on the image acquired using this result, the influence of beam scattering can be removed. However, when the distance between the diaphragm and the sample is different from the input person's assumption, the image restoration result may be inappropriate. In that case, instead of using the automatically calculated value, the user manually inputs the beam diameter d1 of the non-scattered charged particle beam, the beam diameter d2 of the scattered charged particle beam, and the ratio N0 / (N0 + N1) of the non-scattered charged particle beam. May be. You may provide the button 726,727 which can select whether these values are calculated automatically or a user inputs. On the other hand, when this operation is complicated, the part 725 for setting parameters may not be displayed. Since the user can input parameters used for the image restoration process in this way, the user can search for a beam shape that is closer to reality. Alternatively, it is possible to obtain knowledge that the beam shape used when the image is the closest to the ideal image as a result of the user adjusting the parameters is close to the actual beam shape.

  If an image is called up and a file in which image acquisition information when the image is acquired is read, it is possible to save time and effort for inputting the acceleration voltage and the magnification.

  Further, these parameters may be collectively replaced with some parameters and input. For example, the parameter indicates the strength of the deconvolution process. More specifically, the intensity level of the image restoration process is divided into 1 to 10 so that level 1 corresponds to d2 / d1 = 10 and level 10 corresponds to d2 / d1 = 1000. In this case, input means such as a slider bar may be displayed instead of inputting numerical values of parameters. In this way, the user performs image restoration at the image restoration processing level, and if the result is not satisfactory, the image restoration may be performed again at another level. The user should select only the image restoration processing level. Therefore, the operation is very simple.

<Specific area image restoration>
FIG. 5 shows the result of processing the entire image. However, when the sample 6 has large irregularities as shown in FIG. 10, the distance between the diaphragm 10 and the sample 6 is not uniform, and the distance between the diaphragm and the sample surface depends on the position on the sample. For example, the distance between the diaphragm and the sample surface is Z1 at the position 6a, whereas the distance between the diaphragm and the sample surface is Z2 at the position 6b. When the distance between the diaphragm and the sample surface varies depending on the position on the sample, the parameter of the scattering lens function varies. Therefore, the beam shape 306 of the charged particle beam that reaches the sample surface when the incident beam shape 305 is incident is as shown in the lower diagram of FIG. That is, the shape of the beam due to the non-scattered charged particles and the number of the scattered charged particles and the number of these differ, so that the beam shape when reaching the sample surface is different. For this reason, it is not optimal to collectively perform image restoration processing with one scattering lens parameter for all regions of the image in which the sample 6a portion and the sample 6b portion are mixed.

  Therefore, the images near 6a and 6b are restored using different parameters. An operation screen for performing this process is shown in FIG. The screen 700 includes a button 710 for reading an image, an image display unit 702 for displaying the read image, and an image display unit 703 for displaying the restored image. The parts not specifically mentioned such as the image restoration parameter setting unit 705 are as described with reference to FIG. The screen 700 is provided with an area setting unit 729 for setting an image restoration area. In the area setting unit 729, a figure such as a square, a circle, or a triangle can be selected, and a range indicated by a desired figure can be input on the image display unit 702. The image included in the displayed figure is restored with the specified parameters. That is, on the screen 700, the user can specify an area for image restoration processing of one image. In addition to known shapes such as squares and circles, it may be possible to set an area so that the user can freely draw an area freehand.

  In addition, it is possible to set a region for image restoration with the same parameter at a plurality of locations for one image. For example, a region 730 and a region 731 in the figure. When the image restoration start button 723 is pressed in such a state, image restoration is started, and the restored image is displayed on the image display unit 703. In this state, the image restoration is performed at two places with the same parameters. Next, when it is desired to perform image restoration with different parameters for another region, for example, when the restoration image call button 729 is pressed, the restored image is called up in the image display unit 702, and then the same procedure is repeated. Thus, it is possible to perform image restoration with another parameter and overwrite the result.

  As another example, as shown in FIG. 12, the image restoration parameter setting unit 705 may be provided with an input field 733 (multiple parameter setting unit) in which parameters can be set for each region. The multi-parameter setting unit may have a button for clearly indicating that the area corresponding to the input numerical parameter can be selected. A parameter is set while a selection button (such as the button for area A in the figure) is pressed, a figure is selected by the area setting unit 729, and an area 730 (A part in the figure) is designated on the image display unit 702. Next, another parameter button (area B button in the figure) is selected in the multiple parameter setting section, and another area 731 (area B in the figure) is similarly selected. In this way, it is possible to restore the image collectively using different parameters for the region 730 and the region 731 included in one image, and thus it is not necessary to read the saved image again. .

<Procedure>
Hereinafter, a procedure for acquiring an image will be described with reference to FIG. First, at step 500, the acceleration voltage E is set. Next, in step 501, an image is captured. Next, in step 502, a desired image is stored. An image to be subjected to image restoration processing is selected from the stored images. Alternatively, a desired image may be called up (step 511). Next, in step 512, the acceleration voltage E and the magnification (or pixel size) when the image is acquired are set. In the next step 503, an area in the image to be restored is set. This step may be omitted when performing image restoration processing on the entire image. Next, in step 504, the diaphragm-sample distance Z is set. As described above, the parameter set in step 504 may be a parameter that is replaced with something other than the diaphragm-sample distance Z. In step 505, parameters relating to the scattered charged particle beam are determined using the set parameters. The parameters relating to the scattered charged particle beam include the beam diameter d1 of the non-scattered charged particle beam, the beam diameter d2 of the scattered charged particle beam, the non-scattered charged particle ratio N0 / (N0 + N1), and the like. As described above, if it is desired to manually input parameters relating to the scattered charged particles, they are input in this step.

  As shown in FIG. 12, when it is desired to set a plurality of image restoration areas, the process returns to step 503 to determine another image restoration area. If the set parameter is a satisfactory value, image restoration is started. Next, the restored image is confirmed (step 507), and if the result is not satisfactory, the parameters are reset. If there is no problem, the restored image is saved (step 510), and the image restoration process is terminated.

  Also, as described above in the description of FIG. 9, since it is very complicated to input parameters in the processing from step 504 to 505, the parameters may be calculated by replacing them with parameters indicating the strength of deconvolution processing. Good.

  In addition, when information such as acceleration voltage and magnification is embedded in the image file itself when the microscope stores the image, or when it is stored in another file, the image file is called in step 511. At this time, it is possible to eliminate step 512 by simultaneously reading these files.

  Note that the image restoration processing of this embodiment can also be performed on a computer independent of the charged particle microscope apparatus. FIG. 14 illustrates this state. A computer 35 is provided in the charged particle microscope apparatus, and a computer 35 ′ is provided independently of the computer 35. The computer 35 and the computer 35 'can transmit and receive data via communication wiring, a recording medium, and the like. The charged particle microscope image acquired in a state including the scattered charged particle beam is transmitted to the computer 35 ′ via the computer 35. In the computer 35 ′, the parameters used for image restoration and the area to be restored can be set by using the operation screen as shown in FIG. 11 or 12. Thereafter, as shown in step 511 of FIG. 13, the image data received by the computer 35 'is called and image restoration is performed. Note that when image restoration is performed by the computer 35 ′ arranged separately, setting units such as charged particle beam irradiation conditions and focus adjustment as in the operation screen of FIG. 9 are unnecessary. According to the embodiment of FIG. 14, it is possible to perform image restoration work on another computer without using the computer 35 that controls the charged particle microscope, so that image acquisition and image restoration can be performed efficiently. In the case of the embodiment of FIG. 14, the image restoration processing of this embodiment can be performed by installing dedicated software in the computer 35 '. This dedicated software has at least a function for displaying an operation screen in which parameters can be set as shown in FIG. 11 or FIG. 12, and a function for determining a scattering lens function and performing image restoration processing using these parameters. This dedicated software is stored in a non-transitory and tangible computer readable recording medium.

  As described in this embodiment or other embodiments, a charged particle beam apparatus that observes a sample under atmospheric pressure may be used by a beginner who is not accustomed to using a charged particle beam apparatus, and can acquire an optimal image. Although it is not always easy to place a sample at a position, according to the method described in this example, a good image can be obtained by performing image restoration even if the distance between the sample and the diaphragm is long. Can be obtained. As a result, it is possible to achieve an effect that the usability is dramatically improved without damaging the diaphragm and the sample.

  As described above, in the present embodiment, the apparatus and method for performing image restoration according to the distance between the sample and the diaphragm have been described. However, each control configuration, wiring route, and operation screen may be arranged in places other than those described above. As long as the functions intended in the embodiment are satisfied, the device belongs to the category of SEM or charged particle beam apparatus of the present embodiment.

  In the following, a description will be given of an apparatus configuration that allows a general charged particle beam apparatus to easily observe a sample in the atmosphere. FIG. 15 shows an overall configuration diagram of the charged particle microscope of the present embodiment. Similar to the first embodiment, the charged particle microscope of the present embodiment also includes a charged particle optical column 2, a casing (vacuum chamber) 7 that supports the charged particle optical column with respect to the apparatus installation surface, a sample stage 5, and the like. Composed. Since the operations and functions of these elements or additional elements added to the elements are substantially the same as those in the first embodiment, detailed description thereof is omitted.

  This configuration includes a second casing (attachment) 121 that is used by being inserted into the casing 7 (hereinafter referred to as a first casing). The second casing 121 includes a rectangular parallelepiped body portion 131 and a mating portion 132. As will be described later, at least one side surface of the rectangular parallelepiped side surface of the main body 131 is an open surface 15. Of the rectangular parallelepiped side surfaces of the main body 131, the surface other than the surface on which the diaphragm holding member 155 is installed may be configured by the wall of the second casing 121, or the second casing 121 itself has no wall and is the first. You may be comprised by the side wall of the 1st housing 7 in the state integrated in the 1 housing 7. FIG. The second housing 121 is fixed to the side surface or inner wall surface of the first housing 7 or the charged particle optical column. The main body 131 has a function of storing the sample 6 to be observed, and is inserted into the first housing 7 through the opening. The mating portion 132 forms a mating surface with the outer wall surface on the side surface side where the opening of the first housing 7 is provided, and is fixed to the outer wall surface on the side surface side via the vacuum sealing member 126. As a result, the entire second housing 121 is fitted into the first housing 7. The opening is most easily manufactured using the opening for loading and unloading the sample originally provided in the vacuum sample chamber of the charged particle microscope. That is, if the second casing 121 is manufactured according to the size of the hole that is originally open and the vacuum sealing member 126 is attached around the hole, the modification of the apparatus is minimized. The second housing 121 can be detached from the first housing 7.

  The side surface of the second housing 121 is an open surface 15 that communicates with the atmospheric space with a surface that is at least large enough to allow the sample to be taken in and out. The inside of the second housing 121 (right side from the dotted line in the figure; The sample 6 stored in the space is placed in an atmospheric pressure state during observation. 15 is a cross-sectional view of the apparatus in the direction parallel to the optical axis, and therefore only one open surface 15 is shown, but it is vacuum-sealed by the side surface of the first casing in the back direction and the front direction in FIG. If so, the open surface 15 of the second casing 121 is not limited to one surface. It is sufficient that at least one open surface is provided in a state where the second housing 121 is incorporated in the first housing 7. On the other hand, a vacuum pump 4 is connected to the first housing 7, and a closed space (hereinafter referred to as a first space) constituted by the inner wall surface of the first housing 7, the outer wall surface of the second housing and the diaphragm 10. Can be evacuated. By arranging the diaphragm so as to keep the pressure in the second space larger than the pressure in the first space, the second space can be isolated in pressure in this embodiment. That is, the first space 11 is maintained in a high vacuum by the diaphragm 10, while the second space 12 is maintained in a gas atmosphere having an atmospheric pressure or almost the same pressure as the atmospheric pressure. The particle optical column 2 and the detector 3 can be maintained in a vacuum state, and the sample 6 can be maintained at atmospheric pressure. Further, since the second casing 121 has an open surface, the sample 6 can be freely exchanged during observation. That is, it is possible to move the sample 6 in the atmosphere or to remove it from the apparatus while the first space 11 is in a vacuum state.

  On the upper surface side of the second housing 121, the diaphragm 10 is provided at a position immediately below the charged particle optical lens barrel 2 when the entire second housing 121 is fitted to the first housing 7. The diaphragm 10 can transmit or pass the primary charged particle beam emitted from the lower end of the charged particle optical column 2, and the primary charged particle beam finally reaches the sample 6 through the diaphragm 10. To do.

  The sample stage 5 is disposed inside the second housing 121. A sample 6 is disposed on the sample stage 5. A sample stage 5 is used to approach the diaphragm 10 and the sample 6. The sample stage may be operated manually, or the sample stage 5 may be provided with a drive mechanism such as an electric motor and operated by electrical communication from the outside of the apparatus.

  As described above, by introducing the attachment unit provided with the diaphragm, it is possible to observe the sample at atmospheric pressure or in a gas atmosphere using a general charged particle beam apparatus that performs imaging under vacuum. Further, the attachment of the present embodiment can be easily increased in size because it is inserted from the side surface of the sample chamber.

  Even with the apparatus configuration of the present embodiment, the method described in the first embodiment can provide an effect that the sample position can be easily and accurately adjusted without damaging the diaphragm and the sample.

  Also in the apparatus configuration described in this embodiment, the above-described image restoration is effective because the beam shape deteriorates due to scattering in the diaphragm and scattering in the air space between the diaphragm and the sample. Since the parameters used for image restoration and the method of image restoration processing are as described above, description thereof will be omitted.

  In FIG. 16, the whole block diagram of the charged particle microscope of a present Example is shown. Similar to the second embodiment, the charged particle microscope of the present embodiment also includes a charged particle optical column 2, a first casing (vacuum chamber) 7 that supports the charged particle optical column with respect to the apparatus installation surface, and a first casing. The second housing (attachment) 121 used by being inserted into the body 7 is constituted by a control system and the like. Since the operations and functions of these elements or additional elements added to the elements are substantially the same as those in the first and second embodiments, detailed description thereof is omitted.

  In the case of the charged particle microscope of the present embodiment, the open surface forming at least one side surface of the second housing 121 can be covered with the lid member 122, and various functions can be realized. This will be described below.

  In the charged particle microscope of the present embodiment, the sample stage 5 as means for moving the observation field of view by changing the sample position is connected to the lid member 122. The sample stage 5 includes an XY drive mechanism in the in-plane direction and a Z-axis drive mechanism in the height direction. A support plate 107 serving as a bottom plate for supporting the sample stage 5 is attached to the lid member 122, and the sample stage 5 is fixed to the support plate 107. The support plate 107 is attached so as to extend toward the inside of the second casing 121 toward the surface of the lid member 122 facing the second casing 121. Support shafts extend from the Z-axis drive mechanism and the XY drive mechanism, respectively, and are connected to the operation knob 108 and the operation knob 109 of the lid member 122, respectively. The apparatus user adjusts the position of the sample 6 in the second housing 121 by operating these operation knobs 108 and 109.

  The charged particle microscope of the present embodiment has a function of supplying a replacement gas into the second housing. For example, a gas cylinder and a gas supply pipe. Alternatively, a function capable of forming a pressure state different from the first space 11 and the outside air outside the apparatus may be provided. For example, a pump that can be evacuated slightly. The charged particle beam emitted from the lower end of the charged particle optical column 2 passes through the diaphragm 10 through the first space maintained at a high vacuum, and further, at atmospheric pressure (rather than the first space). It penetrates into the second space maintained at a low vacuum. Thereafter, the sample 6 is irradiated with a charged particle beam. Since the electron beam is scattered by the gas molecules in the atmospheric space, the mean free path is shortened. That is, if the distance between the diaphragm 10 and the sample 6 is large, the primary charged particle beam, or secondary electrons, reflected electrons, transmitted electrons, etc. generated by charged particle beam irradiation do not reach the sample and the detector 3. On the other hand, the scattering probability of charged particle beams is proportional to the mass number and density of gas molecules. Therefore, if the second space is replaced with gas molecules having a lighter mass number than the atmosphere, or if the vacuum is slightly evacuated, the scattering probability of the electron beam is lowered and the charged particle beam can reach the sample. Become. Further, even if not the entire second space, it is sufficient that at least the passage of the charged particle beam in the second space, that is, the atmosphere between the diaphragm 10 and the sample 6 can be replaced or evacuated.

  For the above reasons, in the charged particle microscope of this embodiment, the lid member 122 is provided with an attachment portion (gas introduction portion) for the gas supply pipe 100. Although referred to herein as a gas supply pipe, it can also be used for slightly evacuating as described above by using it as an exhaust pipe. The gas supply pipe 100 is connected to the gas cylinder 103 by the connecting portion 102, whereby the replacement gas is introduced into the second space 12. A gas control valve 101 is arranged in the middle of the gas supply pipe 100, and the flow rate of the replacement gas flowing through the pipe can be controlled. For this reason, a signal line extends from the gas control valve 101 to the lower control unit 37, and the apparatus user can control the flow rate of the replacement gas on the operation screen displayed on the monitor of the computer 35. The gas control valve 101 may be manually opened and closed.

  As the type of the replacement gas, if the gas is lighter than the atmosphere, such as nitrogen or water vapor, the effect of improving the image S / N can be seen, but helium gas or hydrogen gas having a lighter mass has a better image S / N. Great improvement effect.

  Since the replacement gas is a light element gas, it tends to accumulate in the upper part of the second space 12, and the lower side is difficult to replace. Therefore, an opening that communicates the inside and outside of the second space is provided below the attachment position of the gas supply pipe 100 by the lid member 122. For example, in FIG. 16, an opening is provided at the attachment position of the pressure adjustment valve 104. Thereby, since the atmospheric gas is pushed out by the light element gas introduced from the gas introduction part and discharged from the lower opening, the inside of the second housing 121 can be efficiently replaced with the gas. Note that this opening may also be used as a rough exhaust port described later.

  A pressure regulating valve 104 may be provided instead of the above-described opening. The pressure regulating valve 104 has a function of automatically opening the valve when the internal pressure of the second housing 121 becomes 1 atm or more. By providing a pressure regulating valve with such a function, when light element gas is introduced, it automatically opens when the internal pressure reaches 1 atm or more and discharges atmospheric gas components such as nitrogen and oxygen to the outside of the device. The element gas can be filled in the apparatus. The illustrated gas cylinder or vacuum pump 103 may be provided in a charged particle microscope, or may be attached later by an apparatus user.

  Even light element gases such as helium gas and hydrogen gas may have large electron beam scattering. In that case, the gas cylinder 103 may be replaced with a vacuum pump. Then, by slightly evacuating, the inside of the second housing can be brought into an extremely low vacuum state (that is, an atmosphere having a pressure close to atmospheric pressure). That is, the space between the first diaphragm 10 and the sample 6 can be evacuated. For example, a vacuum exhaust port is provided in the second casing 121 or the lid member 122, and the inside of the second casing 121 is slightly evacuated. Thereafter, a replacement gas may be introduced. The vacuum evacuation in this case does not require high vacuum evacuation because the atmospheric gas component remaining in the second housing 121 may be reduced to a certain amount or less, and rough evacuation is sufficient. In addition, you may have the pressure gauge 80 which can monitor the pressure of the space 12 in this case.

  Although not shown, the cylinder 103 may be a composite gas control unit in which a gas cylinder and a vacuum pump are combined. Although not shown, a heating mechanism for heating the sample 6 may be disposed inside the second casing 121.

  Further, in addition to the secondary electron detector and the backscattered electron detector, an X-ray detector and a photodetector may be provided so that EDS analysis and fluorescent ray detection can be performed. The X-ray detector and the photodetector may be arranged in either the first space 11 or the second space 12.

Thus, in this apparatus configuration, the space in which the sample is placed can be controlled to an arbitrary degree of vacuum from atmospheric pressure (about 10 ⁵ Pa) to about 10 ³ Pa. In the conventional so-called low-vacuum scanning electron microscope, the electron beam column and the sample chamber communicate with each other, so if the pressure in the sample chamber is reduced to a pressure close to atmospheric pressure, the pressure in the electron beam column also changes accordingly. Therefore, it was difficult to control the sample chamber to a pressure of atmospheric pressure (about 10 ⁵ Pa) to about 10 ³ Pa. According to the present embodiment, since the second space and the first space are separated by the thin film, the pressure of the atmosphere in the second space 12 surrounded by the second casing 121 and the lid member 122. And the gas species can be controlled freely. Therefore, the sample chamber can be controlled to a pressure of atmospheric pressure (about 10 ⁵ Pa) to about 10 ³ Pa, which has been difficult to control until now. Furthermore, not only the observation at atmospheric pressure (about 10 ⁵ Pa) but also the state of the sample can be observed by continuously changing the pressure in the vicinity thereof. That is, the configuration according to the present embodiment is characterized in that the second space 12 inside the second housing is closed, as compared with the configuration described above. Therefore, for example, it is possible to provide a charged particle beam apparatus that can introduce gas or evacuate between the diaphragm 10 and the sample 6.

  In the present embodiment, the sample stage 5 and its operation knobs 108 and 109, the gas supply pipe 100, and the pressure adjustment valve 104 are all attached to the lid member 122. Therefore, the user of the apparatus can operate the operation knobs 108 and 109, replace the sample, or operate the gas supply pipe 100 and the pressure adjustment valve 104 on the same surface of the first housing. Therefore, the operability is greatly improved as compared with the charged particle microscope in which the above-described components are separately attached to the other surfaces of the sample chamber.

  In addition to the configuration described above, a contact monitor that detects the contact state between the second housing 121 and the lid member 122 may be provided to monitor whether the second space is closed or open.

  As described above, in addition to the effects of the first and second embodiments, the apparatus according to the present embodiment can perform observation from atmospheric pressure under a desired replacement gas species or a desired pressure. In addition, it is possible to observe the sample in an atmosphere having a pressure different from that of the first space. Further, by removing the diaphragm and allowing the first space and the second space to communicate with each other, in addition to the observation in the atmosphere or in a predetermined gas atmosphere, the sample can be observed in the same vacuum state as the first space. Is realized. Even with the apparatus configuration of the present embodiment, the method described in Embodiments 1 and 2 can provide an effect that the position of the sample can be adjusted easily and accurately without damaging the diaphragm or the sample.

  Also in this embodiment, the primary charged particle beam is scattered by the gas between the diaphragm and the sample, which is a diaphragm and a non-vacuum space. The influence of the scattering on the spot shape of the primary charged particle beam can be removed by the same method as described above. The parameters and calculation processing method are as described above. However, in the apparatus of the present embodiment, when a gas is introduced between the sample and the diaphragm, or when the pressure is lower than the atmospheric pressure, the shape of the sample reaching beam shown in FIG. 4 changes. This is because the scattering lens function of the scattering lens 12a corresponding to the space 12 in FIG. 3 changes.

  That is, the gas type a and the gas pressure P in (Expression 2) change. When a light element gas is introduced into the space between the sample and the diaphragm, it is necessary to set a which has a smaller amount of scattering, and when a vacuum is drawn a little, it is necessary to set a pressure P having a smaller amount of scattering. In addition, when the distance between the sample and the diaphragm is changed by introducing gas or evacuating lightly, it is also necessary to input a new change. As described above, when the light element gas is introduced or the pressure is lower than the atmospheric pressure, the mean free path is extended, and thus the scattered charged particle beam diameter d2 tends to be reduced. Therefore, the operation screen of the apparatus in the present embodiment has a setting unit that can input the gas type a introduced into the space 12 and the gas pressure P measured by the pressure gauge 80 on the operation screen of FIG. Thus, the above-described image restoration can be performed.

  In the present embodiment, a configuration in which the charged particle optical barrel 2 which is a modification of the first embodiment is located below the diaphragm 10 will be described. In FIG. 17, the block diagram of the charged particle microscope of a present Example is shown. A vacuum pump and a control system are not shown in the figure. Further, it is assumed that the housing 7 and the charged particle optical column 2 that are vacuum chambers are supported by columns, supports, and the like on the apparatus installation surface. Since the operation / function of each element or additional elements added to each element are substantially the same as those in the above-described embodiment, detailed description thereof is omitted.

  As shown in FIG. 17A, the apparatus of this embodiment includes a sample stage 5 for bringing the sample 6 close to the diaphragm 10. In the apparatus configuration of this example, the sample surface below the sample 6 in the figure is observed. In other words, in the apparatus configuration of the present embodiment, the upper part of the apparatus is opened as an atmospheric pressure space. Also in this case, the distance between the diaphragm and the sample can be adjusted by the method described in the first and second embodiments.

  As shown in FIG. 17B, the sample 6 may be directly mounted on the diaphragm 10 side (arrow in the figure). In this case, the sample stage 5 is not necessarily required. In order to apply the method described in Embodiments 1 and 2 to the present embodiment to bring the diaphragm and the sample 6 close to each other, a thin film formed with a predetermined thickness between the diaphragm 10 and the sample 6 and removable. A contact preventing member 56 such as a foil material is used. In this case, the contact preventing member 56 corresponds to the distance adjusting mechanism described in the first and second embodiments. By placing the contact prevention member 56, it is possible to arrange the sample 6 with confidence. For example, a plurality of contact prevention members 56 having various known thicknesses are prepared. First, the contact preventing member 56 having a thickness of t1 is disposed on the base 9. Next, the sample 6 is mounted. Thereby, it becomes possible to carry out observation without bringing the diaphragm 10 and the sample 6 into contact with each other and damaging them.

  In any of the configurations of FIGS. 17A and 17B, the above-described image restoration is effective because the beam shape deteriorates due to scattering in the diaphragm and scattering in the air space between the diaphragm and the sample. Since the parameters used for image restoration and the method of image restoration processing are as described above, description thereof will be omitted.

  In the embodiments described above, the apparatus and method for observing a charged particle microscope in which the diaphragm 10 and the sample 6 are arranged in the non-contact state in the atmosphere have been described. In this embodiment, a method for performing image restoration using an apparatus for observing a sample placed in an air atmosphere in a state where the diaphragm and the sample are in contact with each other will be described.

  The general components of the charged particle beam apparatus observed at atmospheric pressure will be described with reference to FIG. Descriptions similar to those in FIG. 3 are omitted. In FIG. 18, the lower surface side of the diaphragm 10 in the figure is a non-vacuum space, and the upper side of the diaphragm 10 in the figure is a vacuum space. The sample is held in contact with the diaphragm 10. A simplified description of this configuration is as shown in FIG. Since the sample is in contact with the diaphragm 10, there is no scattering lens 12a corresponding to the non-vacuum space as described in FIG. That is, only the scattering lens 10a by the diaphragm 10 exists, and the amount of scattering depends on the material type m, the density ρ, the thickness t, and the irradiation energy E of the charged particle beam. Assuming that the scattering lens function (or degradation function) A is based only on the diaphragm, the scattering lens function is described below.

A = A (m, ρ, t, E) (Equation 9)
Further, when the charged particle beam shape before entering the diaphragm is F and the charged particle beam shape after passing through the diaphragm is G, the following is described.

G = A (m, ρ, t, E) × F (Expression 10)
If the beam shape incident on the diaphragm 10 is a beam 305, the beam shape reaching the sample 6 is a beam 306. Since there is no scattering lens (12a in FIG. 3) due to the non-vacuum atmosphere between the diaphragm and the sample, the number of beams caused by scattered charged particles is smaller than in the devices of Examples 1 to 5. That is, the scattered charged particle beam diameter d2 is small. However, scattering by the diaphragm 10 occurs as in the case of FIG. As a result, as in the case of FIG. 3, the beam 307 by the non-scattered charged particle beam and the beam 308 by the scattered charged particle beam are mixed. Therefore, the image restoration method described above is useful.

  FIG. 19 shows a charged particle device in this example. It is assumed that the charged particle optical column 2 and the housing 7 are supported by a pillar or a base (not shown). In addition, as shown in FIG. 17, the charged particle optical column may be arranged below the diaphragm 10. In this configuration, the configuration is the same as that of the first embodiment except that the sample 6 is in contact with the diaphragm 10. As shown in FIGS. 15 and 16 described in the second and third embodiments, a general charged particle microscope apparatus may be provided with an attachment. When the sample is held in direct contact with the diaphragm, after the sample 6 is mounted on the diaphragm holding member 155, the diaphragm holding member 155 is brought into contact with the housing 7, the space 11 is evacuated, and the charged particle beam is irradiated. Get an image. Thereafter, the above-described image restoration is performed on the acquired image.

  As another example, FIG. 20 describes another charged particle microscope apparatus that observes a diaphragm and a sample in contact with each other. In this configuration, a container 100 that can enclose and enclose the sample 6 in a local space in a non-vacuum atmosphere is disposed on the sample stage 5 of the charged particle device. Sample 6 is in contact with diaphragm 10. The sample 6 is directly mounted on the diaphragm 10 provided on the lid 101 of the container 100 outside the charged particle microscope apparatus. The lid 101 and the container 100 are fixed by screws or the like (not shown). As a result, the interior of the container 100 is held in a local atmosphere space different from the space outside the container 100. Next, the container 100 is introduced into the load current microscope apparatus and charged particle microscope observation is performed. In this case, the charged particle beam emitted from the charged particle source 8 passes through several optical lenses 1, then passes through the vacuum space 11, and reaches the sample 6 through the diaphragm 10. In this case, since the outside of the container 100 is evacuated, the only factor that scatters the charged particle beam is mainly the diaphragm 10 as in the apparatus of FIG.

  In the case of an apparatus configuration in which the sample 6 is brought into contact with these diaphragms, the sample portion in contact with the diaphragm 10 is observed. Therefore, charged particle beam scattering depends only on the material type, density, and thickness of the diaphragm 10. Since the parameters related to the diaphragm are known, there is no parameter to be set by the user when calculating (Equation 10). Therefore, when performing image restoration of an image acquired by the charged particle microscope apparatus, it is not necessary to input the distance between the diaphragm and the sample as described in the operation screen of FIG. In other words, it can be said that the distance between the diaphragm and the sample is zero. As a result, the beam shape 306 can be obtained in advance, so that the amount of scattering by the diaphragm is stored in the computer 35, and image restoration processing is always performed with the same parameters at the time of image acquisition. May be. However, the sample part to be observed is not necessarily in contact with the diaphragm. In that case, in order to be able to adjust the scattering amount, it may have some scattering amount adjusting section.

  In the case of the apparatus configuration described in this embodiment, since there is no scattering due to the atmosphere in the non-vacuum space between the diaphragm and the sample, a clearer image can be acquired. Furthermore, since the user does not need to worry about the parameters of the scattering lens function caused by the atmosphere in the non-vacuum space, it is possible to perform simpler image restoration.

In this embodiment, unlike Embodiments 1 to 5, an example will be described in which the diaphragm is not disposed and the sample is disposed under a low vacuum. For example, a low-vacuum SEM that enables SEM observation in a low-vacuum region. In the following, low vacuum means about 10 ⁻¹ Pa to 10 ³ Pa. Also in this case, the charged particle beam is scattered by the gas remaining in the low vacuum environment before reaching the sample. Although the amount of scattering is small compared to the first to fifth embodiments, the above-described image restoration is still effective in the present embodiment.

The general components of the charged particle beam apparatus will be described with reference to FIG. Descriptions similar to those in FIG. 3 are omitted. A space 13 on the lower surface side of the diaphragm 10 is a low vacuum space. The sample is placed under low vacuum. In general, since it is not desirable that the charged particle beam source 8 has a low vacuum around the charged particle beam source 8, the atmosphere of the charged particle beam source 8 is maintained at a high vacuum (10 ⁻¹ Pa or less) by the vacuum pump 4 and the pipe 16. In order to avoid the gas gas in the housing 7 from entering the charged particle source side as much as possible, an aperture 82 having a minute hole is provided. A plurality of apertures may be provided, and the differential pressure may be formed in multiple stages. Hereinafter, the low vacuum space means from the aperture 82 (the aperture closest to the sample when there are a plurality of apertures) to the sample 6 (part h3 in the figure).

  The distance of the low vacuum space h3 (that is, the distance from the aperture to the sample) is determined relative to the working distance that is the distance from the objective lens. The position of the aperture 82 and the position of the objective lens 303 are unique to the apparatus, and the working distance can be grasped from the magnetic field strength of the objective lens 303. That is, the position where the sample is focused can be obtained regardless of the position of the sample. Therefore, the distance of the low vacuum space h3 can be grasped by making a relative comparison with the working distance.

  When this configuration is simplified and described, it is as shown in FIG. Since there is no diaphragm 10 as compared with the above-described embodiment, the scattering lens 13a corresponding to the low vacuum space 13 is a main factor for scattering the charged particle beam. The amount of scattering depends on the distance z (h3 in FIG. 21A) from the diaphragm 10 to the sample 6, the gas type a and gas pressure P (or density) in the low vacuum space, and the irradiation energy E of the charged particle beam. In other words, when the scattering lens function (or degradation function) A in the low vacuum space in this case is assumed, the scattering lens function is described below.

A = A (a, P, z, E) (Formula 11)
Further, when the charged particle beam shape before passing through the low vacuum space is F and the charged particle beam shape after passing through the low vacuum space is G, the following is described.

G = A (a, P, z, E) × F (Formula 12)
When the beam shape incident on the low vacuum space is a beam 305, the beam shape reaching the sample 6 is a beam 306. Since there is no scattering lens 12a due to the diaphragm, the amount of scattering is less than that of the devices of the first to fifth embodiments due to scattered charged particles. That is, the scattered charged particle beam diameter d2 is small. However, since the beam 307 is a non-scattered charged particle beam and the beam 308 is a scattered charged particle beam, the image restoration method described above is useful.

  FIG. 22 shows an example of a charged particle device in this embodiment. In this apparatus, a sample is placed in the low vacuum space 13. An aperture 82 is provided in the charged particle optical column 2 so that the gas inside the housing 7 does not enter the charged particle source 8. In order to make the inside of the housing 7 have a low vacuum degree, a leak valve 81 and a pressure gauge 80 are provided. The leak valve 81 is connected to, for example, the atmosphere side, and atmospheric gas can be introduced into the housing 7 by the opening / closing amount of the leak valve. Further, the pressure can be measured by the pressure gauge 80. The leak valve 81 and the pressure gauge 80 are electrically connected to the control unit 36, and the degree of vacuum can be controlled by the computer 35. Although not shown, a plurality of vacuum pumps may be provided so that the gas is not mixed into the charged particle source via the pipe 16. Such an apparatus has a data processing unit capable of image restoration similar to the above. By the above-described image restoration processing, image quality can be improved by image restoration of an image acquired under a low vacuum.

  FIG. 23 shows an example of the operation screen. Descriptions similar to those in FIG. 9 are omitted. The operation screen 700 is provided with a vacuum degree setting unit 733 capable of setting the degree of vacuum inside the housing 7 and making the set degree of vacuum. The image restoration parameter setting unit 705 includes an input field 734 for setting the distance of the low vacuum space h3. Instead, the sample height or the working distance with the objective lens may be input to the input field 734, and the distance of the low vacuum space h3 may be obtained using this value. An input field 735 for setting the degree of vacuum is also provided. As other conditions, an acceleration voltage and a magnification are set. Thus, the image restoration parameter is determined, and the above-described image restoration can be performed. In this way, the image restoration process can be optimized according to the parameters input by the user parameters.

  If the image to be restored is called and processed, or if the displayed image is accompanied by information indicating the conditions at the time of image acquisition, the conditions such as acceleration voltage and magnification are known, so the user No need to enter. In addition, even if the image restoration processing is performed by a computer installed separately from the charged particle beam device, the sample position, working distance, vacuum degree, acceleration voltage, and magnification when the image was acquired If a file in which image acquisition information is described is read, it is possible to save the user from inputting all or part of the parameters described above.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor.

  Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or an optical disk.

  Further, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

1: optical lens, 2: charged particle optical column, 3: detector, 4: vacuum pump, 5: sample stage, 6: sample, 7: housing, 8: charged particle source, 9: base, 10: diaphragm , 11: first space (or vacuum space), 12: second space (or atmospheric space), 13: low vacuum space, 14: leak valve, 16: vacuum piping, 17: stage support, 18: support column , 19: Support member for lid member, 20: Bottom plate, 33: Monitor, 34: User interface such as keyboard and mouse, 35: Computer, 36: Control unit, 43, 44, 45: Communication line, 52: Base, 53 : Optical axis, 60: Data transmission / reception unit, 61: Data memory unit, 62: External interface, 63: Data processing unit, 64: Stage control unit, 80: Pressure gauge, 81: Leak valve, 82: Aperture, 100: Gas Supply pipe, 101: valve for gas control, 102: connecting part, 103: gas cylinder or vacuum pump, 104: pressure adjusting valve, 107: support plate, 108, 109: operation knob, 121: second casing, 122, 130 : Lid member, 123, 124, 125, 126, 128, 129: Vacuum sealing member, 131: Main body part, 132: Matching part, 154: Signal amplifier, 155: Diaphragm holding member, 155: Base, 200: Optical axis 301: Lens 1, 302: Lens 2, 303: Lens 3, 305: Incident beam shape, 306: Sample arrival beam shape, 307: Unscattered charged particle beam shape, 308: Scattered charged particle beam shape, 400: Distance control Member, 401: sample stage, 402: female screw, 407: vacuum sealing member, 408: distance control member, 500: step, 700: operation screen, 01: Condition setting unit, 702: Image display unit, 703: Image display unit after image restoration, 704: Image adjustment unit, 705: Threshold setting unit, 706: Irradiation energy E setting unit, 707: Irradiation start button, 708: Irradiation Stop button, 709: Image save button, 710: Image readout button, 711: Diaphragm-sample distance setting unit, 713: Image restoration start button, 715: Focus adjustment unit, 716: Brightness adjustment unit, 717: Contrast adjustment unit 720: Unscattered charged particle size setting unit, 721: Scattered charged particle size setting unit, 722: Unscattered charged particle ratio setting unit, 723: Image restoration start button, 724: Automatic contrast adjustment button, 725: Manual input unit, 726: Automatic input selection button, 727: Manual input selection button, 728: Automatic noise adjustment button, 729: Image restoration area setting unit, 73 : Setting unit, 731: setting unit, 732: magnification setting unit, 733: multi-parameter setting unit, 734: Vacuum degree setting unit

Claims (18)

A charged particle optical column whose inside is evacuated,
A sample stage for placing the sample in a non-vacuum space;
A detector for detecting secondary charged particles obtained by irradiating the sample with a primary charged particle beam emitted from the charged particle optical column;
A data processing unit that removes an influence on the spot shape of the primary charged particle beam from being scattered by the primary charged particle beam before reaching the sample from the signal of the detector;
A diaphragm capable of maintaining a differential pressure between a space communicating with the inside of the charged particle optical column and maintained in a vacuum state and a non-vacuum space in which the sample is disposed, and transmitting or passing the primary charged particle beam And comprising
The data processing unit may be affected by a spot shape of the primary charged particle beam having a width of 10 nm to 10000 nm and / or the primary charged particle beam scattered when the primary charged particle beam passes through the diaphragm. caused by the charged particle beam is by Ri scattered gases present in the non-vacuum space, the impact width is 10nm or more 10000nm following the primary charged particle beam spot shape is removed from the signal of the detector, Charged particle beam equipment.   The charged particle beam apparatus according to claim 1, wherein the data processing unit obtains an influence generated on a spot shape of the primary charged particle beam according to a material type, a density, and a thickness of the diaphragm.   The data processing unit obtains an influence on a spot shape of the primary charged particle beam according to a type of the gas, a distance through which the primary charged particle beam passes through the non-vacuum space, and a pressure of the gas. Item 2. A charged particle beam apparatus according to Item 1.   The ratio between the length h1 of the charged particle optical column and the distance h2 through which the primary charged particle beam passes in the non-vacuum space is h1 / h2 ≧ 1000, and h2 is 1 mm or less. Charged particle beam equipment.   The data processing unit was scattered before reaching the sample of the primary charged particle beam and the spot shape of the non-scattered charged particle beam that was not scattered before reaching the sample of the primary charged particle beam The charged particle beam apparatus according to claim 1, wherein a spot shape model of the primary charged particle beam when reaching the sample is generated using a spot shape of a scattered charged particle beam.   The charged particle beam apparatus according to claim 1 or 5, wherein a width of a spot shape of a non-scattered charged particle beam that has not been scattered before reaching the sample among the primary charged particle beam is 1 nm or more and 100 nm or less.   Of the primary charged particle beam, the width of the spot shape of the non-scattered charged particle beam that has not been scattered before reaching the sample is d1, and the scattered charge that is scattered until the sample reaches the sample of the primary charged particle beam. The charged particle beam apparatus according to claim 1, wherein the relationship between the d1 and the d2 satisfies d2 / d1 ≧ 10, where d2 is a spot shape width of the particle beam.   2. The charged particle beam according to claim 1, further comprising: a display that displays an operation screen that allows a user to specify a region to be processed for image restoration out of one image formed based on a signal from the detector. apparatus.   Of the one image formed on the basis of the signal from the detector, a first region in which image restoration processing is performed using a first parameter set is different from the first parameter set. The charged particle beam apparatus according to claim 1, further comprising: a display that displays an operation screen that allows a user to designate a second area on which image restoration processing is performed using the parameters. The primary charged particle beam is emitted from the charged particle optical column whose inside is evacuated,
Irradiating a sample placed in a non-vacuum space with the primary charged particle beam,
A secondary charged particle obtained by irradiating the sample with the primary charged particle beam is detected by a detector,
Removing from the signal of the detector the influence caused on the spot shape of the primary charged particle beam by being scattered before the primary charged particle beam reaches the sample;
The primary charged particle beam emitted from the charged particle optical column has a differential pressure between a space communicating with the inside of the charged particle optical column and maintained in a vacuum state and a non-vacuum space in which the sample is arranged. Permeates or passes through a diaphragm that is maintainable,
The influence of the spot shape of the primary charged particle beam having a width of 10 nm to 10000 nm and / or the primary charged particle beam caused by scattering when the primary charged particle beam passes through the diaphragm, and / or caused by being scattered Ri by the gas present in the vacuum space, the impact width is 10nm or more 10000nm following the primary charged particle beam spot shape is removed from the signal of the detector, the sample image acquiring method. The sample image acquisition method according to claim 10 , wherein an influence generated on a spot shape of the primary charged particle beam is obtained according to a material type, density, and thickness of the diaphragm. The sample image according to claim 10 , wherein an influence generated on a spot shape of the primary charged particle beam is determined according to a type of the gas, a distance that the primary charged particle beam passes through the non-vacuum space, and a pressure of the gas. Acquisition method. The spot shape of the non-scattered charged particle beam that was not scattered before reaching the sample among the primary charged particle beam and the spot of the scattered charged particle beam that was scattered before reaching the sample among the primary charged particle beam shape was used to generate a model of the spot shape of the primary charged particle beam when reaching the sample, determining the effects caused in the spot shape of the primary charged particle beam by using the model, according to claim 10, wherein Sample image acquisition method.   The charged particle beam apparatus according to claim 10 or 13, wherein a width of a spot shape of a non-scattered charged particle beam that has not been scattered before reaching the sample among the primary charged particle beam is 1 nm or more and 100 nm or less.   Of the primary charged particle beam, the width of the spot shape of the non-scattered charged particle beam that has not been scattered before reaching the sample is d1, and the scattered charge that is scattered until the sample reaches the sample of the primary charged particle beam. The charged particle beam apparatus according to claim 10, wherein the relationship between the d1 and the d2 satisfies d2 / d1 ≧ 10, where d2 is a spot shape width of the particle beam. The sample image acquisition method according to claim 10 , wherein an image restoration process is performed on a part of a region designated by a user among one image formed based on a signal from the detector. Of the one image formed on the basis of the signal from the detector, a first region in which image restoration processing is performed using a first parameter set is different from the first parameter set. The sample image acquiring method according to claim 10 , wherein the user can designate the second region to be subjected to image restoration processing using the parameters. A charged particle optical column whose inside is evacuated,
A sample stage for placing the sample in a non-vacuum space;
A detector for detecting secondary charged particles obtained by irradiating the sample with a primary charged particle beam emitted from the charged particle optical column;
A diaphragm capable of maintaining a differential pressure between a space communicating with the inside of the charged particle optical column and maintained in a vacuum state and a non-vacuum space in which the sample is disposed, and transmitting or passing the primary charged particle beam A program recording medium on which a program to be executed by a computer connected to a charged particle beam apparatus is recorded,
The program performs a process of removing the influence generated on the spot shape of the primary charged particle beam from the signal of the detector by being scattered before the primary charged particle beam reaches the sample, and
The influence of the spot shape of the primary charged particle beam having a width of 10 nm to 10000 nm and / or the primary charged particle beam caused by scattering when the primary charged particle beam passes through the diaphragm, and / or caused by being scattered Ri by the gas present in the vacuum space, the impact width is 10nm or more 10000nm following the primary charged particle beam spot shape, it performs a process of removing from the signal of the detector, the program recording medium .

Images