JP6419849B2 - Charged particle beam equipment - Google Patents

Description

  The present invention relates to a charged particle beam apparatus.

  The charged particle beam apparatus scans a primary charged particle beam, detects signal charged particles emitted from a sample with a detector, and forms an image with the signal of the detected signal charged particles. In this charged particle beam apparatus, the primary charged particle beam and the signal charged particle are both electrons are called a scanning electron microscope (SEM).

  The SEM has a higher spatial resolution than the optical microscope, and its application is wide-ranging in the field of materials such as electronics and functional materials, or the field of biotechnology such as cells and pharmaceuticals.

  In SEM, signal electrons generated by irradiating a specimen with primary electrons are detected. The contrast of the obtained SEM image changes depending on the energy and emission angle of the detected signal electrons. In order to obtain an optimal contrast for SEM images of various samples, there is an increasing demand for a technique for selecting and detecting only signal electrons that contribute to contrast among signal electrons emitted from the sample.

  The signal electrons are roughly classified into low-energy secondary electrons of usually less than 50 eV and high-energy backscattered electrons of 50 eV or more. The secondary electrons are emitted from the free electrons in the sample by inelastic scattering of the primary electrons and emitted into vacuum. Although all electrons generated due to irradiation of primary electrons as secondary electrons in a broad sense are sometimes referred to as secondary electrons, in the following, electrons having an energy of less than 50 eV are referred to as secondary electrons.

  Since secondary electrons have low energy, those generated inside the sample are absorbed in the sample, and only those generated near the sample surface are released from the surface to the outside of the sample. Therefore, information on the surface shape and potential contrast of the sample can be obtained from the SEM image in which secondary electrons are detected. On the other hand, backscattered electrons are re-emitted from the surface of the sample in the process of the primary electrons being elastically scattered or inelastically scattered in the sample, and the energy range is widely distributed with the energy of the primary electrons as the maximum value. Further, in the SEM image in which backscattered electrons are detected, information on the composition and crystal orientation of the sample can be obtained depending on the atomic number and crystallinity.

  In addition, important information may be obtained by detecting signal electrons emitted in a specific elevation range or azimuth range. When the primary electrons are vertically incident on a flat sample, the distribution of the generation amount of the signal electrons follows the cosine side with respect to the elevation angle and is uniform with respect to the azimuth angle. For this reason, an SEM image in which the bottom of the high aspect structure is emphasized can be obtained by limiting the angle range of the detected signal electrons to the vicinity of the normal direction of the sample surface. Further, by detecting only in a specific azimuth angle range, an SEM image in which the unevenness of the pattern is enhanced by the shadow effect is obtained.

  Furthermore, there is an increasing need to perform angle-selective detection of signal electrons emitted from a sample while maintaining high SEM spatial resolution. There are a retarding method and a boosting method as a method for obtaining a high spatial resolution in a state where the incident energy of the primary electrons on the sample is low.

  In the retarding method, electrons incident on the sample are decelerated by applying a negative voltage to the sample stage. An electrostatic lens (cathode lens) is formed between the sample and the objective lens by the negative voltage applied to the sample stage. As a result, spherical aberration and chromatic aberration are reduced and the quality of the SEM image is improved. In addition, the deceleration electric field for the primary electrons is an acceleration electric field for the secondary electrons emitted from the sample.

  In the boosting method, an electrode (beam booster) for applying a positive voltage is inserted inside the column, the primary electrons are accelerated and passed through the objective lens, and after passing through the objective lens, decelerated to the original acceleration voltage. Since this beam booster ends near the end of the objective lens, an electrostatic lens is generated between the end of the objective lens and the sample. Similar to the retarding method, this electrostatic lens acts as a decelerating electric field for primary electrons and as an accelerating electric field for signal electrons emitted from the sample.

Japanese Patent Application Laid-Open No. 08-124513

  Although there is a need for angle selection of signal charged particles emitted from a sample, signal charged particle angle information may be lost due to several factors. This may be caused by the fact that the signal charged particles are deflected due to the influence of the magnetic field of the objective lens and lose the angle information, or the signal charged particles lose the angle information due to the retarding voltage or the electric field due to the retarding voltage. .

  Therefore, the present invention provides a technique for selecting and detecting an angle range without losing angle information (elevation angle and azimuth angle) of signal charged particles emitted from an observation sample.

  For example, in order to solve the above-mentioned problem, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. To give an example, a primary charged particle beam source that emits a primary charged particle beam, a deflector for scanning the primary charged particle beam, An objective lens for focusing the primary charged particle beam on a sample, a sample stage on which the sample is mounted, a detector for detecting signal charged particles emitted from the sample, the primary charged particle beam and the signal charged particles A diaphragm having at least one opening through which the aperture passes, the diaphragm being positioned between the objective lens and the sample stage, and the aperture depending on a detection angle range of the signal charged particles Provided is a charged particle beam device configured to change at least one of the shape of the portion and the height of the diaphragm.

  According to the present invention, the angle range can be selected and detected without losing the angle information of the signal charged particles emitted from the observation sample. Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. Further, problems, configurations and effects other than those described above will be clarified by the description of the following examples.

It is a whole lineblock diagram showing the outline of SEM concerning the 1st example. It is a figure explaining the definition of the elevation angle and azimuth of a secondary electron. It is a figure which shows another form (all column type booster electrode) of the booster electrode in SEM concerning 1st Example. It is a 1st example of the aperture_diaphragm | restriction with which the hole diameter in SEM concerning 1st Example was fixed. It is a 2nd example of the aperture_diaphragm | restriction with which the hole diameter in SEM concerning 1st Example was fixed. It is a 3rd example of the aperture_diaphragm | restriction with which the hole diameter in SEM concerning 1st Example was fixed. It is a 4th example of the aperture_diaphragm | restriction with which the hole diameter in SEM concerning 1st Example was fixed. FIG. 5 is a side sectional view of a diaphragm control mechanism used for the diaphragm of FIGS. 4A to 4D. FIG. 5 is a plan view from above of a diaphragm control mechanism used for the diaphragm of FIGS. 4A to 4D. It is an example of the aperture_diaphragm | restriction which can select the hole diameter in SEM concerning 1st Example. It is an example of the shielding board in SEM concerning 1st Example. FIG. 6 is a side sectional view of a diaphragm control mechanism used for the diaphragm of FIGS. 6A to 6B. FIG. 6 is a plan view from above of a diaphragm control mechanism used for the diaphragm of FIGS. 6A to 6B. It is a 1st example of the aperture_diaphragm | restriction which can change the hole diameter in SEM concerning 1st Example. It is a 2nd example of the aperture_diaphragm | restriction which can change the hole diameter in SEM concerning 1st Example. It is a 3rd example of the aperture_diaphragm | restriction which can change the hole diameter in SEM concerning 1st Example. It is a top view from the upper part of the aperture-control mechanism used for the aperture_diaphragm | restriction of FIG. 8A. It is the figure which looked at the detector using ExB in the SEM concerning the 1st example from the side. It is the figure which looked at the detector using ExB in SEM concerning the 1st example from the upper part. It is a figure explaining the structure of the detector which used the conversion board in SEM concerning 1st Example. It is a flowchart which selects the angle of a secondary electron in SEM concerning 1st Example, and acquires a SEM image. It is a figure which shows an example of the GUI screen which a user performs the setting for angle selection in SEM concerning 1st Example. It is a whole block diagram which shows the outline of SEM which does not use the boosting method and the retarding method in SEM concerning 1st Example. It is a whole block diagram which shows the outline of SEM concerning 2nd Example. It is a figure which shows an example of the GUI screen which a user performs the setting for angle selection in SEM concerning 2nd Example. It is a whole block diagram which shows the outline of SEM concerning 3rd Example. It is a figure which shows an example of the GUI screen which a user performs the setting for angle selection in SEM concerning 3rd Example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The accompanying drawings show specific embodiments in accordance with the principle of the present invention, but these are for the understanding of the present invention, and are never used to interpret the present invention in a limited manner. is not.

  The following embodiments relate to a charged particle beam apparatus that scans a primary charged particle beam, detects signal charged particles emitted from a sample with a detector, and forms an image with the signal of the detected signal charged particles. . Hereinafter, the SEM using electrons as the primary charged particle beam and the signal charged particle will be described as an example. However, the scope of application of the present invention is not limited to the SEM, and can be applied to other charged particle beam apparatuses. For example, the effect of the present invention can be obtained even with a helium ion microscope using helium ions as the primary charged particle beam.

  As described above, all electrons generated due to irradiation of primary electrons as secondary electrons in a broad sense are sometimes referred to as secondary electrons. Hereinafter, electrons having an energy of less than 50 eV are referred to as secondary electrons. Call it. In addition, the effect of this invention can be acquired also when the boundary of a secondary electron and a backscattered electron is defined in other than 50 eV.

[First embodiment]
FIG. 1 shows the overall configuration of the SEM relating to the present embodiment. The SEM includes an electron source (primary charged particle beam source) 101 that emits primary electrons (primary charged particle beam) 102, a deflector 117 for scanning the primary electrons 102, a booster electrode 103, and the primary electrons 102 as a sample. Objective lens 104 that converges on 106, sample stage 107 on which sample 106 is mounted, detector 109 that detects secondary electrons (signal charged particles) 108 emitted from sample 106, primary electrons 102 and secondary electrons And a diaphragm 105 having an opening (hole) through which 108 passes.

  The detector 109 includes a signal processing unit 110. The aperture 105 includes an aperture control mechanism 113. The SEM also includes a booster power supply 111, an objective lens power supply 112, a retarding control power supply 114, and a deflector power supply 118 as power supplies for various components.

  The information processing unit 115 is connected to the signal processing unit 110, the aperture control mechanism 113, the booster power supply 111, the objective lens power supply 112, the retarding control power supply 114, and the deflector power supply 118. The information processing unit 115 controls these components and executes various types of information processing. The image display terminal 116 includes an input unit (such as a mouse and a keyboard) that performs input to the information processing unit 115 and a display unit (such as a display) that displays an output from the information processing unit 115.

  The signal processing unit 110 and the information processing unit 115 described above may be realized using a general-purpose computer, or may be realized as a function of a program executed on the computer. The computer includes at least a processor such as a CPU (Central Processing Unit), a storage unit such as a memory, and a storage device such as a hard disk. The processing of the signal processing unit 110 and the information processing unit 115 may be realized by storing the program code in a memory and causing the processor to execute each program code. Note that part of the signal processing unit 110 and the information processing unit 115 may be configured by hardware such as a dedicated circuit board.

  In FIG. 1, primary electrons 102 generated by the electron source 101 pass through a booster electrode 103, a deflector 117, and an objective lens 104. The primary electrons 102 irradiate the sample 106 placed on the sample stage 107, whereby secondary electrons 108 are generated.

  The objective lens 104 is driven by the objective lens power source 112, and the deflector 117 is driven by the deflector power source 118. Further, a booster electrode 103 is applied with a positive booster voltage by a booster power supply 111. A negative retarding voltage is applied to the sample stage 107 from a retarding control power source 114. The voltage applied by the booster power supply 111 and the retarding control power supply 114 is based on the ground potential. The secondary electrons 108 are accelerated by the retarding voltage.

  The diaphragm 105 is installed between the deflector 117 and the sample 106 and between the objective lens 104 and the sample 106. In other words, the stop 105 is disposed below the deflector 117 for correcting the trajectory and below the objective lens 104.

  The accelerated secondary electrons 108 are further accelerated at the booster electrode 103 after passing through the aperture of the aperture 105. Thereafter, the accelerated secondary electrons 108 are deflected by the deflector 117 and detected by the detector 109. The signal detected by the detector 109 is processed by the signal processing unit 110, and the information processing unit 115 forms an image from the information from the signal processing unit 110 and displays the image on the image display terminal 116. Thereby, the user can confirm the image formed by the signal detected by the detector 109.

  A method of applying a positive voltage (booster voltage) to the booster electrode 103 by the booster power source 111 and accelerating the primary electrons 102 when passing through the objective lens 104 is called a boosting method. A method of decelerating the primary electrons 102 immediately above the sample 106 by applying a negative voltage (retarding voltage) to the sample 106 by the retarding control power supply 114 is called a retarding method.

  In the boosting method and the retarding method, by decelerating the primary electrons 102 immediately before the sample 106, an electrostatic lens is formed between the sample 106 and the objective lens 104, and the aberration of the primary electrons 102 is reduced. This is a technique that can realize spatial resolution.

  The form of the booster electrode 103 is not limited to the configuration shown in FIG. FIG. 3 shows the overall configuration of an SEM including another form of booster electrode 103. In FIG. 3, the configuration other than the booster electrode 103 is the same as that in FIG. In FIG. 1, the booster electrode 103 is installed in a space near the objective lens 104. On the other hand, in FIG. 3, the booster electrode 103 is installed in the space from the electron source 101 to the objective lens 104. The effect of the present invention can be obtained in the configurations of both FIG. 1 and FIG.

  Here, the electric field formed by the booster voltage and the retarding voltage acts as an accelerating electric field for the secondary electrons 108. In other words, changing the booster voltage and / or the retarding voltage affects not only the trajectory of the primary electrons 102 but also the trajectory of the secondary electrons 108. Typically, the booster voltage and the retarding voltage may be positive and negative voltages of several kV, respectively. However, the absolute value of the voltage described above is merely a typical value, and is not limited to this.

  FIG. 2 is a diagram for explaining the definition of the elevation angle (θ) and the azimuth angle (φ) of the secondary electrons 108. With respect to the elevation angle (θ) of the secondary electron 108, the normal direction is 90 degrees and the horizontal direction is 0 degrees with respect to the sample surface. Thereafter, the elevation angle near 90 degrees is a high angle, the elevation angle near 0 degrees is a base angle, and a high angle. The middle angle is about 45 degrees in the intermediate zone between the angle and the base angle. The azimuth angle (φ) represents an angle in the horizontal plane of the sample 106, and the range of the azimuth angle is 0 degree to 360 degrees.

  The objective lens 104 in FIG. 1 is preferably an out-lens type objective lens in which the elevation angle information of the secondary electrons 108 is stored. The reason why the elevation angle information is stored is that the out-lens objective lens has no influence on the trajectory of the secondary electrons 108 because the leakage magnetic field on the sample is suppressed. However, the objective lens system is not limited to the out lens type. For example, a snorkel type objective lens or an in-lens type objective lens that has a shorter focal length and a smaller spherical aberration coefficient and chromatic aberration coefficient than the out lens and enables high-resolution observation can be used. However, the snorkel type objective lens and the in-lens type objective lens greatly change the secondary electron trajectory under the influence of a strong leakage magnetic field. This problem can be solved by making the distance between the aperture 105 and the sample 106 extremely small and selecting the angle before the trajectory of the secondary electrons 108 changes.

  As a configuration of the detector 109 illustrated in FIG. 1, an Everhart Thornley (ET) type detector positioned above the objective lens 104 is used. The ET type detector is composed of a scintillator to which a high voltage is applied, and a photomultiplier tube that collides signal charged particles with the scintillator and converts them into photons, and multiplies the photons inside to convert them into electrical signals. Yes. The signal obtained by the detector 109 is processed by the signal processing unit 110. Information obtained as a result of processing in the signal processing unit 110 is displayed as a scanned image (SEM image) on the image display terminal 116 via the information processing unit 115. When displaying an image, the user can select appropriate information using the input unit of the information processing unit 115 and display the selected information on the image display terminal 116.

  The detector 109 is not limited to the ET type detector, and may be a semiconductor detector or a micro channel plate (MCP). The installation location of the detector 109 is not limited between the electron source 101 and the deflector 117, and may be installed between the objective lens 104 and the deflector 117. The detector 109 may be installed at a position closer to the sample stage 107 than the objective lens 104 and above the diaphragm 105.

  In order to perform angle selection detection of the secondary electrons 108 emitted from the sample 106, a diaphragm 105 is installed between the objective lens 104 and the sample 106. By installing the aperture 105 between the objective lens 104 and the sample 106, the aperture 105 of the aperture 105 is formed in a state where the electron trajectory of the secondary electrons 108 emitted from the sample 106 is not converged due to factors such as the magnetic field of the objective lens 104. Only the secondary electrons passing through (that is, secondary electrons whose angle range is selected) 108 are detected by the detector 109.

  Depending on the detection angle of the secondary electrons 108, the diaphragm 105 has (1) the shape (including not only the shape but also the size) of the hole (opening) of the diaphragm, and (2) at least the height of the diaphragm 105. It is configured so that one can be changed. More specifically, the user changes at least one of the hole diameter and shape of the diaphragm 105 and the distance between the diaphragm 105 and the sample 106 to change the secondary electrons 108 detected by the detector 109. The angle range can be selected.

  FIG. 4A to FIG. 4E are diagrams showing an example of the diaphragm 105 and showing a diaphragm with a fixed hole shape. The diaphragms 401 to 404 have holes (openings) that define at least one range of an elevation angle and an azimuth angle. In this example, SEM images can be acquired by appropriately replacing the diaphragms 401 to 404 according to the detection angle range.

  Each of the diaphragms 401 to 404 is a thin plate-like member, and has a hole through which the primary electrons 102 and the secondary electrons 108 pass. The diaphragms 401 to 404 are desirably as thin as possible (for example, about 0.1 mm). This is because the secondary electrons 108 scattered on the side walls of the holes of the apertures 401 to 404 can be detected.

  Further, it is desirable that the size of the diaphragm (that is, the size when viewed in plan view) is larger than that of the sample 106 to be observed. FIG. 4A shows an example in which the planar view size of the diaphragm 401 is larger than the planar view size of the sample 106. This is because if the size of the diaphragm 401 is small, not only the secondary electrons 108 that pass through the aperture of the diaphragm 401 but also the secondary electrons 108 that have passed outside the diaphragm 401 may be detected by the detector 109. Because.

  Further, in order to prevent charging due to the collision of the primary electrons 102 and the secondary electrons 108 with the stop 105, the material of the stop 105 is preferably a metal. In this embodiment, molybdenum is used as the material of the diaphragm 105, but the effects of the present invention can be obtained even with other metals.

  Further, the secondary electrons 108 that pass near the center of the hole (opening) of the aperture 105 and the secondary electrons 108 that pass near the end of the aperture of the aperture 105 respectively pass through the opening of the aperture 105. Is different. Therefore, when the magnification of the SEM image is low, the angles detected at the center and the edge of the image are different. In order to prevent this, it is desirable that the field of view of the SEM image is about 1% of the aperture of the aperture 105. Specifically, when the aperture 105 has a hole with a hole diameter of R1.1 mm, the field of view is preferably about 11 μm.

  A diaphragm 401 shown in FIG. 4A is a sufficiently thin plate, and has a hole 401a having an arbitrary hole diameter R at the center thereof. The diaphragm 401 is installed at a distance D from the sample 106. Although not shown, the objective lens 104 exists above the diaphragm 401.

  The primary electrons 102 and the secondary electrons 108 pass through the hole 401a. In the case of the diaphragm 401, the detection angle of the secondary electrons 108 is selected within one angle range determined geometrically from the distance D and the hole diameter R. Specifically, when the distance between the objective lens 104 and the sample 106 is 4 mm, the distance between the diaphragm 401 and the sample 106 is 1.5 mm, and the hole diameter R is 1.1 mm, the elevation angle is from 70 degrees to 90 degrees. Secondary electrons 108 pass through the hole 401a. When it is desired to detect another angle range, a diaphragm 401 having a hole diameter R ′ having a different size may be inserted into the SEM for each measurement. If only the lower limit value of the elevation angle is adjusted, the diaphragm 401 may be moved in the z-axis direction to reduce the distance between the diaphragm 401 and the sample 106.

  In this embodiment, the diaphragm control mechanism 113 can adjust the position of the diaphragm 401 so that the position of the center of gravity of the hole 401 a of the diaphragm 401 matches the optical axis of the primary electrons 102. 5A and 5B show an example of the aperture control mechanism 113. FIG.

  The aperture control mechanism 113 includes a support portion 501 for attaching the aperture 401, an x-axis screw 502, a y-axis screw 504, and a z-axis screw 503. An end of the diaphragm 401 is attached to the support section 501 and the diaphragm 401 is disposed on the xy plane. By rotating the x-axis screw 502, the y-axis screw 504, and the z-axis screw 503, the support portion 501 can be moved in the x-axis, y-axis, and z-axis directions. The aperture control mechanism 113 described with reference to FIGS. 5A and 5B can also be applied to the other apertures 402 to 404 shown in FIGS. 4B to 4D. Further, the support portion 501 of the aperture control mechanism 113 is configured such that the apertures 401 to 404 can be appropriately attached and detached in accordance with the detection angle range.

  In the case of the diaphragm 401 in FIG. 4A, only the secondary electrons 108 from an elevation angle of 90 degrees close to the optical axis to a certain angle can pass through the hole 401a of the diaphragm 401. When the user wants to detect a specific angle range of the elevation angle, a shape like a diaphragm 402 shown in FIG. 4B may be used.

  The diaphragm 402 in FIG. 4B has a first hole 402a and a second hole 402b. The first hole 402a is at the center of the diaphragm 402 and is a hole through which the primary electrons 102 pass. The second hole 402b is a ring-shaped hole outside the first hole 402a. The secondary electrons 108 that have passed through the space of the second hole 402 b are detected by the detector 109. Strictly speaking, secondary electrons 108 passing through the first hole 402a can also be detected by the detector 109, but the result obtained by the detector 109 is substantially in the angular range defined by the second hole 402b. Can be regarded as information.

  For example, when the distance between the objective lens 104 and the sample 106 is 4 mm and the distance between the diaphragm 402 and the sample 106 is 1.5 mm, the inner diameter of the ring defining the second hole 402b is 1.7 mm, and the ring When the outer diameter of the secondary electron is 5.2 mm, the secondary electrons 108 having an elevation angle of 30 to 60 degrees can be passed through the second hole 402b. Even in the case of the diaphragm 402, in order to change the angle range to be detected, the diaphragm 402 may be replaced with a diaphragm 402 having a hole size of another size for each measurement. As another example, the angle range to be detected may be changed by moving the diaphragm 401 in the z-axis direction and changing the distance between the diaphragm 401 and the sample 106. The diaphragm 402 in FIG. 4B is effective when observing the sample 106 in which the secondary electrons 108 tend to be emitted in a specific elevation range.

  The diaphragm 401 and the diaphragm 402 described above are diaphragms that select the elevation angle of the secondary electrons 108, but a diaphragm form that selects the azimuth angle may be used. 4C and 4D show stops 403 and 404 for selecting an azimuth angle.

  The diaphragm 403 in FIG. 4C has a first hole 403a and a second hole 403b. The first hole 403a is at the center of the diaphragm 403 and is a hole through which the primary electrons 102 pass. The second hole 403b is composed of two fan-shaped holes arranged around the first hole 402a. The secondary electrons 108 within a certain azimuth angle range pass through the space of the second hole 403 b, and these secondary electrons 108 can be detected by the detector 109. The diaphragm 403 in FIG. 4C is effective when observing, for example, the sample 106 having unevenness, in which the secondary electrons 108 tend to be emitted in a specific azimuth angle range.

  The diaphragm 404 in FIG. 4D has a first hole 404a and a second hole 404b. The first hole 404a is at the center of the diaphragm 404 and is a hole through which the primary electrons 102 pass. The second hole 404b of the diaphragm 404 is one fan-shaped hole disposed around the first hole 404a. Unlike the stop 403 in FIG. 4C, the second hole 404b can pass the secondary electrons 108 in one azimuth angle range. By using the diaphragm 404, it is possible to obtain an SEM image in which the shadow contrast is enhanced such that light is applied from the side in the sample 106 having minute unevenness.

  FIG. 6A shows an example of a diaphragm that can select the hole diameter. The plate-like diaphragm 601 has a plurality of holes 601a to 601d having different diameters. A desired hole diameter R is selected using the aperture control mechanism 113, and the center of the hole diameter is aligned with the center of the sample 106. Thereby, it is possible to perform observation by selecting a desired range from a plurality of detection angle ranges.

  Specifically, when the distance between the objective lens 104 and the sample 106 is 4 mm and the distance between the diaphragm 601 and the sample 106 is 1.5 mm, the hole diameter R of the first hole 601a is 1.1 mm, and the second The hole diameter R of the hole 601b is 1.7 mm, the hole diameter R of the third hole 601c is 3.6 mm, and the hole diameter R of the fourth hole 601d is 8.2 mm. In this case, the elevation angle of the secondary electrons 108 passing through the first hole 601a is 70 degrees to 90 degrees, and the elevation angle of the secondary electrons 108 passing through the second hole 601b is 60 degrees to 90 degrees, The elevation angle of the secondary electrons 108 passing through the hole 601c is 40 degrees to 90 degrees, and the elevation angle of the secondary electrons 108 passing through the fourth hole 601d is 20 degrees to 90 degrees.

  Here, as shown in FIG. 6B, the diaphragm 601 includes a shielding plate 602 for shielding three of the four holes 601a to 601d. The shielding plate 602 is disposed above the diaphragm 601. The shielding plate 602 is provided with a notch 602a in part when viewed in plan view. The cutout portion 602a only needs to be formed in a shape and a planar size so that the four holes 601a to 601d are exposed.

  7A and 7B are examples of the aperture control mechanism 113 used for the apertures in FIGS. 6A and 6B, in which the hole diameter can be selected. The aperture control mechanism 113 includes a rotation mechanism for selecting a hole having a desired hole diameter R among the plurality of holes 601a to 601d. In FIG. 7A and FIG. 7B, the same number is attached | subjected to the same component as FIG. 5A and FIG. 5B.

  The aperture control mechanism 113 includes a support portion 501, an x-axis screw 502, a y-axis screw 504, a z-axis screw 503, a rotation shaft 701, and a φ-axis screw 702. The diaphragm 601 is attached to the rotary shaft 701 and is disposed on the XY plane. The rotating shaft 701 is connected to a φ-axis screw 702. Further, the end of the shielding plate 602 is attached to the support portion 501, and the shielding plate 602 is disposed above the diaphragm 601. According to the above configuration, the diaphragm 601 rotates about the rotation shaft 701 on the XY plane by turning the φ-axis screw 702. When the aperture 601 rotates, one of the four holes 601a to 601d is sequentially exposed to the notch 602a of the shielding plate 602. The user may stop the rotation of the φ-axis screw 702 when a hole having a desired hole diameter R is exposed to the notch 602a of the shielding plate 602.

  Further, by rotating the x-axis screw 502, the y-axis screw 504, and the z-axis screw 503, the support portion 501 can be moved in the x-axis, y-axis, and z-axis directions. 602 can be moved in the x-axis, y-axis, and z-axis directions.

  The advantage of the diaphragm 601 is that it is not necessary to open the sample chamber to the atmosphere in order to change the hole diameter R unlike the diaphragm 401 shown in FIG. 4A. That is, by using the diaphragm 601, a desired hole diameter R can be selected from a plurality of different hole diameters without opening the sample chamber to the atmosphere. However, when the center of one hole having the hole diameter R is aligned with the center of the sample 106 to be observed, the secondary electrons 108 that have passed through the adjacent hole may be detected. This problem can be solved by the shielding plate 602. By using the shielding plate 602, when one hole is selected, the remaining plurality of holes are closed. Therefore, the secondary electrons 108 can be prevented from passing through a plurality of adjacent holes.

  For example, as shown in FIG. 6B, when the fourth hole 601d is used, the secondary electrons 108 passing through the fourth hole 601d are detected by the detector 109, but the first to third holes 601a to 601a are used. Since 601c is blocked by the shielding plate 602, the secondary electrons 108 cannot pass through them. The shape of the diaphragm 601 is not limited to a square. As a diaphragm, a plate-like member may be provided with a plurality of holes (openings) having different hole diameters. As another example, the diaphragm 601 may be attached to the support portion 501, and the shielding plate 602 may be attached to the rotating shaft 701. In this case, the shielding plate 602 rotates. Further, the shielding plate 602 may be disposed closer to the sample 106 than the diaphragm 601.

  FIG. 8A to FIG. 8C show examples of a diaphragm that can change the hole diameter while the position of the diaphragm is fixed. The diaphragm control mechanism 113 controls the diaphragms 801 to 803 in FIGS. 8A to 8C, so that the desired hole diameter R can be changed according to the detection angle range in a state where the positions of the diaphragms 801 to 803 are fixed. The advantages of the apertures 801 to 803 in FIGS. 8A to 8C are that an SEM image can be acquired while changing the hole diameter R, and the user can confirm the change of the SEM image according to the change of the hole diameter R on the screen. it can.

  8A includes a first plate member 801a and a second plate member 801b arranged so as to overlap each other. Each of the first plate member 801a and the second plate member 801b has a quadrangular shape and includes a notch on one side. A portion surrounded by the notch portions of the first plate member 801a and the second plate member 801b is a quadrangular hole having a hole diameter R.

  In the aperture 801, the size of the hole diameter R is changed using the first plate member 801a and the second plate member 801b. The hole diameter R decreases as the first plate member 801a and the second plate member 801b approach each other, and the hole diameter R increases as the first plate member 801a and the second plate member 801b move away from each other. . Although both the first plate member 801a and the second plate member 801b can move to adjust the size of the hole diameter R, only one of them can move to adjust the size of the hole diameter R.

  FIG. 9 is an example of the diaphragm control mechanism 113 for driving the diaphragm 801. In FIG. 9, the same number is attached | subjected to the same component as FIG. 5A and 5B.

  The aperture control mechanism 113 includes a drive mechanism for moving the first plate member 801a and the second plate member 801b. In the example of FIG. 9, the support portion 501 is extended in the X direction (left direction in the drawing), and a reverse screw 902 is attached to the extended portion. The reverse screw 902 has two types of tapered portions 902a and 902b, and is connected to the φ-axis screw 901. The first plate member 801a is connected to the first tapered portion 902a of the reverse screw 902, and the second plate member 801b is connected to the second tapered portion 902b of the reverse screw 902.

  For example, when the φ-axis screw 901 is rotated, the first plate member 801a moves to the left, and the second plate member 801b moves to the right. Conversely, when the φ-axis screw 901 is rotated, the first plate member 801a moves to the right and the second plate member 801b moves to the left. Therefore, it is possible to change only the hole diameter R without changing the center of gravity position of the hole of the aperture 801 only by rotating the φ-axis screw 901. The position of the diaphragm 801 can be moved in the x-axis, y-axis, and z-axis directions by rotating the x-axis screw 502, the y-axis screw 504, and the z-axis screw 503.

  Since the maximum value of R depends on the size of the first plate member 801a and the second plate member 801b, the angle range and R required by the user are calculated in advance, and the first plate member 801a is calculated. It is necessary to design the second plate member 801b.

  The diaphragm 802 in FIG. 8B includes a first plate member 802a, a second plate member 802b, a third plate member 802c, and a fourth plate member 802d arranged so as to overlap each other. Each of the first to fourth plate members 802a to 802d has a shape in which one apex portion of a quadrangle is cut out, and a portion surrounded by the cut-out portions is a quadrangular hole having a hole diameter R. An advantage of the diaphragm 802 is that an arbitrary rectangular hole other than a square can be formed by independently moving each of the first to fourth plate members 802a to 802d in the x direction and the y direction. .

  The aperture control mechanism 113 for the aperture 802 can be mounted with the same configuration as that in FIG. For example, the aperture control mechanism 113 includes a drive mechanism that moves each of the first to fourth plate members 802a to 802d independently in the x direction and the y direction. Specifically, a method of attaching a plurality of θ-axis screws to the support portion 501 and connecting each of the first to fourth plate members 802a to 802d to each θ-axis screw with the same configuration as in FIG. .

  In addition to the secondary electrons 108 from the center of the sample 106 to be observed, if necessary, only the fourth plate member 802d is moved with the first to third plate members 802a to 802c fixed. Thus, it is possible to detect only half of the secondary electrons 108 from the center of the observation sample. In this case, the size of the first to fourth plate members 802a to 802d in plan view needs to be sufficiently larger than the observation sample.

  The diaphragm 803 in FIG. 8C includes five diaphragm blade members 803a to 803e arranged so as to overlap each other. According to this configuration, the hole diameter R can be changed by moving the five diaphragm blade members 803a to 803e like the diaphragm of the camera. The diaphragm blade members 803a to 803e have curved portions at least at the inner edges, and a portion surrounded by the curved portions is a substantial circle or ellipse having a hole diameter R. As shown in FIG. 8C, the outer edges of the diaphragm blade members 803a to 803e may be curved portions.

  Note that the shape formed by the curved portions of the inner edges of the five aperture blade members 803a to 803e is not a perfect circle. Therefore, although the angular resolution may be lower than that of the diaphragm 401 shown in FIG. 4A, the configuration of FIG. 8C has an advantage that a continuous SEM image can be acquired while maintaining a shape close to a circle.

  The diaphragm 803 in FIG. 8C includes five diaphragm blade members 803a to 803e, but the number of blade members is not limited to five. In addition, the larger the number of wing members, the closer the shape of the hole formed by the inner edges thereof to a circle.

  The aperture control mechanism 113 for the aperture 803 is the same as the mechanism for moving the aperture of the camera. For example, the five diaphragm blade members 803a to 803e are arranged on a ring-shaped substrate. The substrate is provided with guide grooves along the movement locus of each wing member, and each wing member and the guide groove are connected by a guide member such as a pin. And each wing member can be opened and closed by moving each wing member by a driving ring provided on the substrate. The mechanism for driving the diaphragm blade member is not limited to this, and other known shutter mechanisms may be applied.

  The angles of the secondary electrons 108 that pass through the diaphragms shown in FIGS. 4A to 4D, FIGS. 6A, and 8A to 8C are the working distance (WD, the distance between the sample 106 and the objective lens 104) and the distance D (the diaphragm 105 and the sample 106). (Distance) may be fixed to a certain value and selected. In the above description, the method of changing the hole diameter R of the diaphragm 105 is used to set an arbitrary detection angle. However, the same effect can be obtained by fixing the hole diameter R and changing the distance D. For example, in the diaphragm 401 of FIG. 4A, when the WD is fixed to a constant value and the distance D is reduced, the secondary electrons 108 passing through the diaphragm can select a range from a high angle to a low angle. Specifically, when the hole diameter R is 1.7 mm, when D is changed from 0.1 mm to 5.0 mm, the minimum elevation angle of the secondary electrons 108 passing through the aperture of the aperture changes from 7 degrees to 80 degrees (maximum Is always 90 degrees). Such an effect applies to all aperture shapes listed above. In order to obtain the above effect, the diaphragm control mechanism 113 has a drive mechanism for changing the distance D by moving the position of the diaphragm 105 in the same direction (z direction) as the optical axis of the primary electrons 102. .

  The detector 109 shown in FIG. 1 needs to detect the secondary electrons 108 that have passed through the diaphragm 105. When the boosting method is used, the secondary electrons 108 that have passed through the diaphragm 105 are accelerated by the electric field between the booster electrode 103 and the diaphragm 105 and pass through the objective lens 104. Therefore, it is necessary to install the detector 109 on the electron source 101 side with respect to the objective lens 104.

  In this case, an Everhart Thornley (ET) type detector can be used. The ET type detector includes a scintillator to which a positive high voltage is applied, a light guide for taking out photons generated when signal charged particles collide with the scintillator, and a photomultiplier tube for converting photons into electric signals. It consists of and. The secondary electrons 108 that have passed through the objective lens 104 are attracted to and detected by a scintillator to which a positive voltage has been applied.

  However, in the above case, it is conceivable that the primary electrons 102 are deflected by an electric field generated by a positive voltage applied to the scintillator. This problem can be solved by using an ExB deflector.

  10A and 10B show examples of detectors using ExB deflectors. The ExB deflector 1001 is an optical element in which the electric field and the magnetic field are orthogonal to each other, and the magnitudes of the electric field and the magnetic field are set so that the primary electrons 102 are not deflected. At this time, the secondary electrons 108 traveling in the direction opposite to the primary electrons 102 are deflected by the electric and magnetic fields described above and are deflected to the detector 109 side. By applying a positive voltage to the grid 1002, an electric field is generated between the grounded counter electrode 1003 and a magnetic field is generated by passing a current through the coil 1004.

  FIG. 11 shows a configuration of a detector using a conversion plate. The conversion plate 1101 is disposed above the detector 109 and has a hole for allowing the primary electrons 102 to pass therethrough. According to this configuration, the tertiary electrons 1102 generated due to the collision of the secondary electrons 108 with the conversion plate 1101 are drawn into the detector 109 by the ExB deflector 1001. Similar to FIGS. 10A and 10B, the electric field and magnetic field magnitude of the ExB deflector 1001 is set to a condition in which the primary electrons 102 are not deflected. It is deflected to the side of the instrument 109. The configuration shown in FIG. 11 is effective when the energy of the secondary electrons 108 is high, for example, when the retarding method is used.

  The detector 109 is not limited to the ET type detector, but may be a semiconductor detector or a micro channel plate (MCP). The installation location of the detector 109 is not limited between the electron source 101 and the deflector 117, but is installed between the objective lens 104 and the deflector 117, or on the sample stage 107 side with respect to the objective lens 104. May be. Further, a semiconductor detector or MCP may be installed instead of the conversion plate 1101.

  The signal obtained by the detector 109 is processed by the signal processing unit 110. The image signal obtained by the processing is displayed on the image display terminal 116 via the information processing unit 115. When displaying an image, the user can select appropriate information using the input unit of the information processing unit 115 and cause the image display terminal 116 to display the selected information.

  FIG. 12 is a flowchart for taking an SEM image while changing the hole diameter R of the aperture 105 by changing the hole diameter R of the secondary electron 108 emitted from the sample 106 using the aperture 105.

  First, the sample 106 is introduced into the SEM (S1201). Next, the sample 106 is moved to a desired observation position while viewing the SEM image, focus adjustment and astigmatism adjustment are performed, and WD and distance D are set (S1202). In this state, an SEM image of the sample 106 is acquired (S1203). Thereafter, the diaphragm 105 is inserted between the sample 106 and the objective lens 104 (S1204). Next, focus adjustment and astigmatism adjustment are performed (S1205). Next, while viewing the SEM image, the aperture control mechanism 113 is used to align the center of the aperture 105 with the center of the observation position (S1206). Thereafter, an SEM image is acquired (S1207). Next, the diaphragm 105 is taken out (S1208). By the flow up to this point, it is possible to compare the SEM image without the aperture 105 and the SEM image with the aperture 105 inserted (that is, the state in which the angle is selected). Finally, if it is desired to change the setting of WD or distance D and take another SEM image, the process returns to step S1202 and after changing WD or distance D, the remaining steps are executed. Thereby, the SEM images before and after the change of the detection angle range can be compared. If the WD and the distance D are not changed, the observation is terminated as it is (S1209).

  FIG. 13 shows an example of a GUI screen for making settings necessary for the user to perform angle selection detection. The GUI screen of FIG. 13 is displayed on the image display terminal 116, and the user can make settings on the GUI screen using an input unit (mouse, keyboard, etc.).

  The GUI screen 1301 is roughly divided into a part for setting and displaying various parameters and a part for displaying an image. First, after the sample 106 is introduced into the SEM, basic conditions such as acceleration voltage are input to the optical condition input unit 1304. The subsequent setting differs depending on whether the user moves the distance D to select an angle or changes the hole diameter R to select an angle.

  When the angle D is selected by moving the distance D, the user inputs the values of the hole diameter R and WD of the diaphragm 105 inserted in the SEM to the hole diameter input unit 1305 and the WD input unit 1307, respectively, and detects the angle to be detected. The range is input to the detection angle input unit 1306. At this time, the information processing unit 115 determines an appropriate distance D based on the input information. The information processing unit 115 inputs information on the determined distance D to the aperture control mechanism 113, and the aperture control mechanism 113 moves the aperture 105 to the position of the determined distance D. An SEM image acquired under these conditions is displayed on the SEM image display unit 1303.

  When selecting the angle by changing the hole diameter R using the aperture 105 that can change the hole diameter R, the user inputs the values of WD and distance D to the WD input unit 1307 and the distance D input unit 1308, respectively, and detects them. The desired angle range is input to the detection angle input unit 1306. The information processing unit 115 determines an appropriate hole diameter R based on the input information. The information processing unit 115 inputs information on the determined hole diameter R to the aperture control mechanism 113, and the aperture control mechanism 113 controls the aperture 105 so that the determined hole diameter R is obtained. An SEM image acquired under these conditions is displayed on the SEM image display unit 1303.

  The WD, the distance D, and the hole diameter R are displayed on the WD input unit 1307, the distance D input unit 1308, the hole diameter input unit 1305, and the positional relationship display unit 1302 on the GUI screen 1301, and these displays are displayed by the user. Can be confirmed.

  Therefore, by using the GUI screen 1301, it is possible to change at least one of the shape of the opening of the diaphragm 105 and the height of the diaphragm 105 in accordance with information input to the GUI screen 1301. Further, the user can check the SEM image of the selected detection angle range while changing the detection angle range.

  According to the present embodiment, by limiting the angle of the signal charged particles by the diaphragm 105 before passing through the objective lens, only the secondary electrons 108 in a specific angle range can be detected. For example, secondary electrons in a specific angle range cannot be discriminated due to the influence of the magnetic field of the objective lens in the objective lens or at a position above the objective lens. On the other hand, since the present embodiment discriminates the angle before passing through the objective lens, the angle information (elevation angle and azimuth angle) of the signal charged particles emitted from the observation sample is not lost. A range can be selected and detected.

  The present embodiment can provide an SEM that can selectively detect signal charged particles, in particular, low-energy secondary electrons 108 with high angular resolution and can achieve both high spatial resolution. There are a retarding method, a boosting method, and the like as a method for obtaining a high spatial resolution in a state where the incident energy of the primary electrons to the sample is low. This embodiment is particularly effective for these methods.

  As described above, the boosting method is effective for obtaining a high spatial resolution, but the electric field generated by the booster voltage exerts a convergence action on the secondary electrons 108. That is, when the diaphragm 105 is not used, there is a possibility that the angle information when the secondary electrons 108 are emitted from the sample 106 is lost when the secondary electrons 108 are accelerated by the booster voltage. However, when the diaphragm 105 is installed between the objective lens 104 and the sample 106, the secondary electrons 108 that have passed through the diaphragm 105 have already known the emission angle. Has no effect.

  In addition, this embodiment can obtain a high spatial resolution with respect to the retarding method. The secondary electrons 108 are accelerated at the same time as the primary electrons 102 are decelerated by the retarding voltage. Therefore, when no voltage is applied to the diaphragm 105, the secondary electrons 108 are deflected between the diaphragm 105 and the sample 106, and the angle information may be lost. Therefore, regarding this problem, it is desirable to apply a voltage having the same polarity to the diaphragm 105 and the sample 106. Note that the voltage applied to the diaphragm 105 and the sample 106 is not limited to a voltage having the same polarity.

  FIG. 14 is an overall configuration diagram showing an outline of an SEM that does not use the boosting method and the retarding method. As shown in FIG. 14, an effect can be obtained by installing a diaphragm 105 between the objective lens 104 and the sample 106 even in an SEM in which the retarding voltage and the booster voltage are not adapted. In this case, the spatial resolution of the primary electrons 102 deteriorates, but the angle of the secondary electrons 108 can be selected. Since the signal charged particles that have passed through the objective lens 104 are converged by the lens magnetic field with a rotational motion corresponding to the energy, the signal charged particles often lose angle information. According to this configuration, angle discrimination can be performed before passing through the objective lens 104, and an SEM image with angle discrimination can be obtained.

[Second Embodiment]
FIG. 15 shows the overall configuration of the SEM relating to the present embodiment. The matters described in the first embodiment and not described in the present embodiment are the same as those in the first embodiment.

  The information processing unit 115 includes an image storage unit 1501 that stores SEM images. The user sets the first condition (shape, hole diameter R, distance D between the diaphragm 105 and the sample 106, etc.) of the diaphragm 105, and acquires an SEM image under the first condition. The first SEM image acquired under the first condition is stored in the image storage unit 1501.

  Next, the user sets a second condition for the aperture 105 that is different from the first condition, and acquires an SEM image under the second condition. The second SEM image acquired under the second condition is stored in the image storage unit 1501. The information processing unit 115 can perform arithmetic processing on a plurality of SEM images stored in the image storage unit 1501. Specifically, a differential image or a composite image of a plurality of SEM images can be created. Note that the calculation process here is not limited to the difference process and the synthesis process, and other processing processes may be performed.

  FIG. 16 shows an example of a GUI screen for performing settings necessary for performing angle selection detection and SEM image calculation processing settings. The GUI screen 1301 includes an SEM image display unit 1601 that displays a first image acquired under the first condition and a second image acquired under the second condition. The GUI screen 1301 includes a calculation SEM image display unit 1602 that displays an image obtained by performing calculation processing (subtraction processing or addition processing) on the first image and the second image. The calculation SEM image display unit 1602 includes a calculation setting unit 1603 for setting the type of calculation. The calculation setting unit 1603 is, for example, a pull-down setting unit, and the type of calculation processing to be executed on the first image and the second image, such as a difference image (A−B) and a composite image (A + B). This is a setting unit that can select.

  In the example of FIG. 16, the first image acquired in the angle range A and the second image acquired in the angle range B are displayed on the SEM image display unit 1601. A difference image (A−B) is set in the calculation setting unit 1603. In this case, if the angle ranges A and B are settings related to the elevation angle, an image in which a specific elevation angle range as obtained by the diaphragm 402 shown in FIG. 4B is selected can be displayed by the subtraction process. If the angle ranges A and B are settings related to the azimuth angle, an image in which a specific azimuth angle range such as that obtained by the diaphragms 403 and 404 shown in FIGS. 4C and 4D is selected can be displayed by subtraction processing.

  In the case of the addition process, for example, a composite image of the first image in the angle range A and the second image in the angle range B is obtained, and an image in which a plurality of angle ranges are selected can be displayed.

  Although not shown in FIG. 16, the information processing unit 115 performs calculation by assigning an arbitrary weight to each SEM image (first image, second image) when performing the above-described calculation processing. Also good. In addition, although an example in which two SEM images are arithmetically processed has been described with reference to FIG. 16, arithmetic processing may be performed on three or more SEM images acquired under three or more conditions regarding the aperture 105. The values of WD, R, and D and their positional relationship can be confirmed on the positional relationship display unit 1302.

  According to the present embodiment, by acquiring and storing a plurality of images under a plurality of conditions related to the aperture 105, the user selects any combination from the plurality of images, and arbitrarily selects those combinations. Can be executed. Therefore, by acquiring images under a plurality of conditions in advance, the user can check the images while appropriately changing the angle range.

[Third embodiment]
FIG. 17 shows the overall configuration of the SEM relating to the present embodiment. Note that the matters described in the above-described embodiment and not described in the present embodiment are the same as those in the above-described embodiment.

  The boosting method used in this embodiment has an effect of improving the spatial resolution. When the boosting method is used, if the hole diameter R of the diaphragm 105 located between the objective lens 104 and the sample 106 is increased or the distance D between the diaphragm 105 and the sample 106 is decreased, the electron trajectory of the secondary electrons 108 is obtained. May be affected by the booster voltage. As a means for avoiding this influence, the SEM includes a tip electrode 1701 and a tip electrode power source 1702. The tip electrode 1701 is located between the booster electrode 103 and the diaphragm 105. The tip electrode power source 1202 can apply an arbitrary voltage to the tip electrode 1701.

  When the aperture diameter R of the aperture 105 is small, the electric field generated by the booster voltage is shielded by the aperture 105, so that even the low-energy secondary electrons 108 have secondary electrons 108 having a wider angle than the aperture diameter R of the aperture 105. Do not pass. However, as the diameter R of the aperture 105 of the aperture 105 increases, the smaller the secondary electrons 108, the more the secondary electrons 108 are converged by the booster electric field leaking from the aperture 105 and pass through the aperture 105. This is similar to the development that occurs in a snorkel type objective lens, and the angle selection mechanism using the aperture 105 becomes a factor.

  This problem can be solved by applying a negative voltage to the tip electrode 1701 disposed at a position close to the aperture 105 and controlling the electric field formed in the vicinity of the aperture of the aperture 105. The voltage applied to the tip electrode 1701 depends on the hole diameter R of the diaphragm 105, the distance between the diaphragm 105 and the objective lens 104, and the voltage of the booster electrode. Accordingly, it is desirable that the voltage applied to the tip electrode 1701 is preset by the apparatus manufacturer as a function of the hole diameter R of the diaphragm 105, the distance between the diaphragm 105 and the objective lens 104, and the booster electrode.

  FIG. 18 shows an example of a GUI screen for making settings necessary for the user to perform angle selection detection. The GUI screen 1301 includes a tip electrode voltage input unit 1801. As shown in FIG. 18, the user may input an arbitrary value to the tip electrode voltage input unit 1801 on the GUI screen 1301 as the voltage applied to the tip electrode 1701. Even if the voltage of the tip electrode 1701 is 0 kV, the angle selection mechanism of the diaphragm 105 is established.

  Note that the voltage applied to the tip electrode 1701 may be changed according to the hole diameter R of the aperture 105. It is also possible to select the angle of the secondary electrons 108 that pass through the hole diameter R by changing the voltage applied to the tip electrode 1701 while fixing the hole diameter R of the aperture 105. For example, when the voltage of the tip electrode 1701 is reduced under the condition of the hole diameter R of the same aperture 105, the elevation angle of the secondary electrons 108 can be detected up to a high angle, but when the voltage of the tip electrode 1701 is increased, it can be detected up to a middle angle. .

  Although the three embodiments have been described above, the numerical values of the apparatus configuration are merely examples, and the present invention is not limited to these.

  The present invention is not limited to the above-described embodiments, and includes various modifications. The above 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. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Moreover, the structure of another Example can also be added to the structure of a certain Example. Further, with respect to a part of the configuration of each embodiment, another configuration can be added, deleted, or replaced.

  The processing of the signal processing unit 110 and the information processing unit 115 described above can also be realized by a program code of software that realizes these functions. In this case, a storage medium in which the program code is recorded is provided to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing it constitute the present invention. As a storage medium for supplying such program code, for example, a flexible disk, CD-ROM, DVD-ROM, hard disk, optical disk, magneto-optical disk, CD-R, magnetic tape, nonvolatile memory card, ROM Etc. are used.

  The processes and techniques described herein are not inherently related to any particular apparatus and can be implemented by any suitable combination of components. In addition, various types of devices for general purpose can be used. In some cases, it may be beneficial to build a dedicated device to perform the processing described here. That is, a part of the signal processing unit 110 and the information processing unit 115 described above may be realized by hardware using electronic components such as an integrated circuit.

  Furthermore, in the above-described embodiments, control lines and information lines are those that are considered necessary for explanation, and not all control lines and information lines on the product are necessarily shown. All the components may be connected to each other.

DESCRIPTION OF SYMBOLS 101: Electron source 102: Primary electron 103: Booster electrode 104: Objective lens 105: Diaphragm 106: Sample 107: Sample stand 108: Secondary electron 109: Detector 110: Signal processing part 111: Booster power supply 112: Objective lens power supply 113 : Diaphragm control mechanism 114: retarding control power supply 115: information processing unit 116: image display terminal 117: deflector 118: deflector power supply 401, 402, 403, 404: diaphragm 501: support unit 502: x-axis screw 503: z Shaft screw 504: y-axis screw 601: aperture 602: shielding plate 602a: notch 701: rotating shaft 702: φ-axis screw 801, 802, 803: iris 901: φ-axis screw 902: reverse screw 1001: ExB deflector 1002 : Grid 1003: Counter electrode 1004: Coil 1101: Conversion plate 1 102: Tertiary electron 1202: Power supply for tip electrode 1301: GUI screen 1302: Position relation display unit 1303: SEM image display unit 1304: Optical condition input unit 1305: Hole diameter input unit 1306: Detection angle input unit 1307: WD input unit 1308: Distance D input unit 1501: Image storage unit 1601: SEM image display unit 1602: Calculation SEM image display unit 1603: Calculation setting unit 1701: Tip electrode 1702: Tip electrode power supply 1801: Tip electrode voltage input unit

Claims (12)

A primary charged particle beam source that emits a primary charged particle beam; and
A deflector for scanning the primary charged particle beam;
An objective lens for focusing the primary charged particle beam on the sample;
A sample stage on which the sample is mounted;
A detector for detecting signal charged particles emitted from the sample;
A charged particle beam apparatus Ru and a diaphragm having at least one opening for the primary charged particle beam and the signal charged particles to pass through,
The diaphragm is positioned between said sample stage and said objective lens, and to be able to change the height of the diaphragm from said shape and said sample of said opening in response to the detection angle range of the signal charged particles is configured to,
The charged particle beam device further includes a display unit that displays a screen for setting at least one of a shape of the opening of the diaphragm and a height of the diaphragm,
The screen includes an input unit for inputting the shape of the opening, the detection angle range, the distance between the sample and the objective lens, and the height from the sample to the diaphragm,
The charged particle beam device further includes an information processing unit that controls at least one of a shape of the opening and a height from the sample to the diaphragm,
The information processing section is input to the detection angle range input to the input section, a distance between the sample and the objective lens input to the input section, and input to the input section. Further, according to the shape of the opening, by controlling the height from the sample to the diaphragm, the angle range of the signal charged particles detected by the detector is controlled,
The information processing section is input to the detection angle range input to the input section, a distance between the sample and the objective lens input to the input section, and input to the input section. The charged particle beam apparatus , wherein the angular range of the signal charged particles detected by the detector is controlled by controlling the shape of the opening according to the height from the sample to the diaphragm . The charged particle beam apparatus according to claim 1,
The charged particle beam apparatus according to claim 1, wherein the aperture of the diaphragm defines at least one of an elevation angle and an azimuth angle of the signal charged particles. The charged particle beam apparatus according to claim 1,
A charged particle beam apparatus, further comprising a diaphragm control mechanism that controls at least one of a shape of the opening of the diaphragm and a height of the diaphragm. In the charged particle beam device according to claim 3,
The diaphragm has a plurality of openings having different shapes,
A shielding member having a notch that exposes one of the plurality of openings of the diaphragm;
The aperture control mechanism is configured to rotate the aperture or the shielding member to sequentially expose one of the plurality of apertures from the notch. . In the charged particle beam device according to claim 3,
The diaphragm includes a plurality of members arranged so as to overlap each other, and the opening is a portion surrounded by the plurality of members,
The charged particle beam device according to claim 1, wherein the aperture control mechanism is configured to change the shape of the opening by moving at least one of the plurality of members. In the charged particle beam device according to claim 3,
Before SL diaphragm control mechanism, a charged particle beam apparatus characterized by controlling at least one of the shape and the aperture of the height of the opening of the throttle in accordance with the information entered on the screen. The charged particle beam apparatus according to claim 1,
Wherein the information processing unit, the image formed of the information from the detector, the display unit, the charged particle beam apparatus characterized by that displays the image. The charged particle beam device according to claim 7 ,
An image storage unit for storing a plurality of images acquired under a plurality of conditions of the aperture;
The charged particle beam apparatus, wherein the information processing unit performs a calculation process on the plurality of images and displays the calculated image on the display unit. The charged particle beam apparatus according to claim 1,
The charged particle beam apparatus further comprising means for accelerating or decelerating the primary charged particle beam. The charged particle beam apparatus according to claim 9 , wherein
The means is means for applying a voltage to the sample stage and decelerating the primary charged particle beam immediately before the sample,
A charged particle beam apparatus, wherein a voltage having the same polarity is applied to the sample and the diaphragm. The charged particle beam apparatus according to claim 9 , wherein
The means is means for applying a voltage to at least a space near the objective lens to accelerate the primary charged particle beam,
A charged particle beam apparatus, wherein a tip electrode for applying a voltage is provided between the aperture and the acceleration means. The charged particle beam device according to claim 11 ,
The charged particle beam device characterized in that the voltage of the tip electrode is set according to the shape of the opening, the distance between the diaphragm and the objective lens, and the voltage of the accelerating means .

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