JP2012058148A - X-ray detection system - Google Patents

Abstract

In an X-ray detection system that diffracts characteristic X-rays from a sample irradiated with an electron beam and collects a spectrum, the energy distribution spectrum detection accuracy is improved by providing an X-ray focusing mirror that performs appropriate focusing. maintain.
An electron beam irradiation unit that irradiates a sample with an electron beam, an X-ray condensing mirror that collects characteristic X-rays emitted from the sample irradiated with the electron beam and guides them to a diffraction grating, An X-ray collector mirror adjustment unit that adjusts the position or angle of the X-ray collector mirror; a diffraction grating that generates a characteristic X-ray that is collected by the X-ray collector mirror; And an image sensor for detecting diffracted X-rays generated by the diffraction grating, wherein the X-ray focusing mirror adjusting unit reflects the energy of the characteristic X-ray reflected on the reflection surface of the X-ray focusing mirror. The position or angle of the X-ray collector mirror is adjusted within a possible angle range.
[Selection] Figure 1

Description

  The present invention relates to an X-ray detection system, and more particularly to an X-ray detection system having a configuration in which characteristic X-rays emitted from a sample are collected by a mirror and guided to a diffraction grating in a state appropriate to the X-ray energy. The present invention relates to an X-ray detection system that can be used.

  When the sample is irradiated with a charged particle beam such as an electron beam, characteristic X-rays are generated from the sample. A technique for detecting the characteristic X-rays with a detector and measuring the composition of the sample is called energy dispersive X-ray spectroscopy. This technique utilizes the characteristic X-rays having the specific energy of the elements constituting the sample. The number of X-rays generated per unit time is counted for each X-ray energy to obtain information such as the elemental composition of the sample. Here, as a means for detecting X-rays, a semiconductor detection element using a semiconductor crystal such as silicon or germanium is generally used.

  On the other hand, when characteristic X-rays generated by irradiating a sample with a charged particle beam such as an electron beam are incident on the diffraction grating, the diffracted X-rays are separated. There is also a technique for detecting the diffracted X-rays with an X-ray CCD image sensor and imaging it.

  An apparatus for realizing this technique includes an electron beam irradiation unit that irradiates a sample with an electron beam, and an X-ray collection that collects characteristic X-rays emitted from the sample irradiated with the electron beam and guides them to a diffraction grating. An optical mirror, a diffraction grating that receives characteristic X-rays collected by the X-ray condenser mirror and generates diffracted X-rays, and an image sensor that detects diffracted X-rays generated by the diffraction grating. ing.

  This type of X-ray detection system is also described in Patent Document 1 below.

JP 2002-329473 A

  Some X-ray detection systems as described above are configured to be able to select and use a plurality of different diffraction gratings according to the difference in X-ray energy. However, the X-ray collector mirror that guides X-rays from the sample to the diffraction grating is not exchanged according to the energy of the X-rays.

  Here, when the X-ray energy, that is, the wavelength is different, the critical angle of reflection is different. Therefore, although medium energy X-rays can be reflected by the X-ray condensing mirror, even if the angle is the same, high energy X-rays are not reflected. That is, it is difficult to realize an X-ray condenser mirror that always ideally reflects X-rays in an X-ray detection system in which various types of energy are detected according to the diffraction grating. In this case, if the position and angle of the X-ray condensing mirror do not match the X-ray energy, the condensing efficiency is lowered and the aberration in reflection is reduced, so that the resolution of the energy distribution spectrum is lowered. The detection accuracy may be reduced.

  The present invention has been made in view of the above problems, and an object thereof is an X-ray detection system that diffracts characteristic X-rays from a sample irradiated with an electron beam by a diffraction grating and collects a spectrum with an image sensor. An X-ray detection system that can maintain the detection accuracy of the energy distribution spectrum by providing an X-ray condensing mirror that performs appropriate condensing according to the energy of X-rays is realized.

  That is, the present invention for solving the above problems is as described below.

  (1) According to the present invention, an electron beam irradiation unit that irradiates a sample with an electron beam, and X-ray condensing that condenses characteristic X-rays emitted from the sample irradiated with the electron beam and guides them to a diffraction grating A diffraction grating that generates a diffracted X-ray upon receipt of a characteristic X-ray collected by the X-ray collector mirror, an X-ray collector mirror adjustment section that adjusts the position or angle of the X-ray collector mirror And an image sensor that detects the diffracted X-rays generated by the diffraction grating, and the X-ray collector mirror adjustment unit is configured to detect the energy of the characteristic X-ray reflected on the reflection surface of the X-ray collector mirror. The X-ray detection system is characterized in that the position or angle of the X-ray collector mirror is adjusted within a range of angles that can be reflected according to a fixed critical angle.

  (2) In the above (1), when the energy of the characteristic X-ray is large, the X-ray collector mirror adjustment unit may increase the incident angle of the characteristic X-ray with respect to the X-ray collector mirror. When the energy of the characteristic X-ray is small, adjustment is performed so that the incident angle of the characteristic X-ray with respect to the X-ray collector mirror is reduced.

  (3) In the above (1)-(2), the X-ray focusing mirror adjustment unit may be configured such that the position of the X-ray focusing mirror or The angle is adjusted.

  (4) In the above (1) to (3), the X-ray focusing mirror adjustment unit includes an analysis unit that analyzes the diffracted X-rays detected by the image sensor and generates an energy distribution spectrum. The position or angle of the X-ray collector mirror is adjusted so that the intensity of any spectral component included in the energy distribution spectrum is increased.

  (5) In the above (1)-(4), the X-ray focusing mirror adjustment unit includes an analysis unit that generates an energy distribution spectrum by analyzing the diffracted X-rays detected by the image sensor. When a decrease in resolution or a decrease in peak level is detected in any spectral component included in the energy distribution spectrum, an angle range that can be reflected is excluded according to a critical angle determined by the energy of the characteristic X-ray. In addition, the position or angle of the X-ray collector mirror is adjusted.

  (6) In addition, in (5), an analysis unit that analyzes the diffracted X-rays detected by the image sensor to generate an energy distribution spectrum is provided, and the X-ray focusing mirror adjustment unit is The position or angle of the X-ray collector mirror is adjusted within a range that can be eliminated.

  (7) Further, in the above (1) to (6), the X-ray condensing system is configured such that a plurality of different diffraction gratings determined according to the energy of the characteristic X-ray can be exchanged. The mirror adjustment unit stores adjustment value data for adjusting the position or angle of the X-ray focusing mirror in accordance with the characteristic X-ray energy corresponding to each of a plurality of different diffraction gratings. The adjustment value stored in accordance with the diffraction grating to be used is read and adjusted.

  According to these inventions, the following effects can be obtained.

  (1) In this invention, characteristic X-rays emitted from a sample irradiated with an electron beam are condensed by an X-ray condenser mirror and guided to a diffraction grating, and the diffraction X-rays generated by the diffraction grating are detected by an image sensor. Then, X-ray detection is performed, and at this time, the position or angle of the X-ray focusing mirror is adjusted by the X-ray focusing mirror adjustment unit.

  Here, the X-ray collector mirror adjustment unit is configured to reflect the X-ray collector mirror within a reflective angle range according to a critical angle determined by the energy of the characteristic X-ray reflected on the reflection surface of the X-ray collector mirror. Adjust the position or angle.

  For this reason, by adjusting the position or angle of the X-ray collector mirror by the X-ray collector mirror adjustment unit, the X-ray collector mirror can perform appropriate focusing according to the energy of the X-ray, and the energy It becomes possible to maintain the detection accuracy of the distribution spectrum.

  (2) In the above (1), the X-ray collector mirror adjustment unit adjusts the incident angle of the characteristic X-ray to the X-ray collector mirror to be large when the characteristic X-ray energy is large, and the characteristic X-ray When the energy of the X-ray is small, by adjusting the incident angle of the characteristic X-ray to the X-ray collector mirror to be small, the X-ray collector mirror can be reflected at each energy of the X-ray. The optical mirror can collect light appropriately according to the energy of the X-ray, and can maintain the detection accuracy of the energy distribution spectrum.

  (3) In the above (1)-(2), the X-ray collector mirror adjustment unit adjusts the position or angle of the X-ray collector mirror in a direction orthogonal to the energy dispersion direction of the image of the diffracted X-ray. Therefore, the X-ray collector mirror has an angle that can be reflected by each energy of the X-ray without affecting the image of the diffracted X-ray, and the X-ray collector mirror collects the light appropriately according to the energy of the X-ray. The detection accuracy of the energy distribution spectrum can be maintained.

  (4) In the above (1)-(3), by adjusting the position or angle of the X-ray focusing mirror so that the intensity of any spectral component included in the energy distribution spectrum is increased, The angle at which the X-ray collector mirror can be reflected with high efficiency at each energy level allows the X-ray collector mirror to perform appropriate focusing according to the energy of the X-ray, maintaining the detection accuracy of the energy distribution spectrum. It becomes possible to do.

  (5) In the above (1)-(4), when a decrease in resolution or a decrease in peak level is detected in any spectral component included in the energy distribution spectrum, it depends on the critical angle determined by the energy of the characteristic X-ray. By adjusting the position or angle of the X-ray focusing mirror so as to exclude the range of angles that can be reflected, the energy distribution spectrum detection accuracy is maintained by actively excluding energy components that are not required for measurement. It becomes possible to do.

  (6) In the above (5), when a decrease in resolution or a decrease in peak level is detected in any spectral component included in the energy distribution spectrum, reflection is possible according to the critical angle determined by the energy of the characteristic X-ray. When adjusting the position or angle of the X-ray collector mirror so as to exclude the angle range, it is not necessary for measurement by adjusting the position or angle of the X-ray collector mirror within the range where the decrease is eliminated. It is possible to maintain the detection accuracy of the energy distribution spectrum by positively and efficiently excluding unnecessary energy components.

  (7) In the above (1) to (6), when the position or angle of the X-ray focusing mirror is adjusted in accordance with the energy of the characteristic X-ray corresponding to each of a plurality of different exchangeable diffraction gratings X-rays associated with the exchange of diffraction gratings are stored by reading adjustment value data stored in accordance with the diffraction grating used and adjusting the position or angle of the X-ray focusing mirror. The X-ray condensing mirror can perform appropriate condensing according to the energy of the X-ray, and can maintain the detection accuracy of the energy distribution spectrum.

It is a block diagram which shows the structure of the X-ray detection system to which embodiment of this invention is applied. It is a block diagram which shows the structure of the X-ray detection system to which embodiment of this invention is applied. It is a block diagram which shows the structure of the principal part of the X-ray detection system to which embodiment of this invention is applied. It is a block diagram which shows the structure of the principal part of the X-ray detection system to which embodiment of this invention is applied. It is a block diagram which shows the structure of the principal part of the X-ray detection system to which embodiment of this invention is applied. It is explanatory drawing which shows the characteristic of the X-ray detection system to which embodiment of this invention is applied. It is explanatory drawing which shows the characteristic of the X-ray detection system to which embodiment of this invention is applied. It is explanatory drawing which shows the characteristic of the X-ray detection system to which embodiment of this invention is applied. It is a block diagram which shows the structure of the principal part of the X-ray detection system to which embodiment of this invention is applied.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments (embodiments) for carrying out an image forming apparatus of the present invention will be described below in detail with reference to the drawings.

<First Embodiment>
First, the configuration of the X-ray detection system of the first embodiment will be described with reference to FIGS. 1 and 2.

  In FIG. 1, known basic members for holding each part such as a lens barrel and a gantry, a mechanism part for holding a vacuum, etc. are omitted, and the arrangement of the characteristic parts of the embodiment is mainly shown. The X-ray detection system is shown in a perspective view. FIG. 2 shows the X-ray detection system in a state close to a block diagram.

  The electron beam irradiation unit 10 is provided in a lens barrel portion of a scanning electron microscope and irradiates the sample 20 with an electron beam.

  The X-ray focusing mirror unit 30 focuses the characteristic X-rays emitted from the sample 20 by the two mirrors 34 a and 34 b and guides them to the diffraction grating 50. Here, by condensing with the X-ray condensing mirror unit 30, the intensity of the characteristic X-rays incident on the diffraction grating 50 can be increased, the measurement time can be shortened, and the S / N ratio of the spectrum can be improved. .

  The X-ray condensing mirror unit 30 is a set of two mirrors 34a and 34b facing each other. The surfaces of the mirrors 34a and 34b facing each other are flat in the direction perpendicular to the paper surface (Z direction) in FIG. The interval between the mirrors is a flat surface, a bent flat surface, or a curved surface in which the sample side (incident side) is narrow and the diffraction grating side (exit side) is wide.

  As a result, the intensity of the characteristic X-rays incident on the diffraction grating 50 can be increased as compared with the case without the X-ray condensing mirror unit 30, thereby shortening the measurement time and improving the S / N ratio of the spectrum. it can.

  Here, for the sake of explanation, the mirrors 34a and 34b are exposed, but the present invention is not limited to this, and a cylindrical structure such as a mirror external housing that integrally holds the mirrors 34a and 34b. The body may be present.

  Further, the X-ray collector mirror unit 30 is angled by an X-ray collector mirror adjusting member 42 (adjustment members 42a, 42b, 42c, 42d) described later on the fixed unit 31 whose position is fixed in the X-ray detection system. Alternatively, the position can be adjusted. In addition, although the fixing | fixed part 31 may be provided as the X-ray condensing mirror part 30, you may use the chassis of an X-ray detection system, etc. as it is.

  The X-ray collector mirror adjustment control unit 41 uses the X-ray collector mirror adjustment member 42 (adjustment members 42a, 42b, 42c, 42d) based on the analysis result in the analysis unit described later to adjust the X-ray collector mirrors 34a, 34b. Adjust the angle or position. The X-ray focusing mirror adjustment control unit 41 and the X-ray focusing mirror adjustment member 42 (adjustment members 42a, 42b, 42c, 42d) constitute an X-ray focusing mirror adjustment unit 40.

  Here, the X-ray focusing mirror adjusting member 42 is adjusted with the adjusting member 42a that adjusts in the X direction (direction orthogonal to the energy dispersion direction of the image of the diffracted X-ray) while supporting the end of the X-ray focusing mirror 34a. And an adjustment member 42c and an adjustment member 42d that adjust in the X direction (direction orthogonal to the energy dispersion direction of the image of the diffracted X-ray) while supporting the end of the X-ray condenser mirror 34b. Configured.

  Here, for the adjustment members 42a and 42c and 42b and 42d, various active adjustment members such as a piezo element, a linear motor, an actuator, and a screw can be used. Further, by using screws as the adjusting members 42a to 42d as a micrometer, it is possible to adjust while confirming the amount of displacement.

  The diffraction grating 50 receives characteristic X-rays collected by the X-ray condenser mirror unit 30 and generates diffracted X-rays having different diffraction states according to energy. This diffractive grating 50 is formed with unequally spaced grooves for aberration correction, and such unequally spaced diffractive gratings are nearly parallel to a large incident angle (diffraction grating surface (Y axis in FIG. 1)). When the light beam is incident at an angle, the focal point of the diffracted light is designed not on the Roland circle but on a plane substantially perpendicular to the light beam (light receiving surface of the image sensor 70: XZ plane in FIG. 1).

  The image sensor 70 is an X-ray CCD camera or an X-ray CMOS camera having sensitivity to soft X-rays in order to detect diffracted X-rays. Desirably, it comprises a back-illuminated X-ray CCD camera. The position of the image sensor 70 is adjusted so that the light receiving surface thereof coincides with the image plane of diffracted X-rays.

  The analysis unit 80 is a waveform analyzer that analyzes the diffracted X-rays detected by the image sensor 70 and generates an energy distribution spectrum that means how many X-rays with a certain value of energy are detected.

  The display unit 90 is a display that visually displays an energy distribution spectrum that is an analysis result of the analysis unit 80 and various other information.

  The analysis unit 80 and the display unit 90 can also be configured by a computer device and a computer program that calculates an energy distribution spectrum.

  The sample 20, the X-ray condensing mirror unit 30, the diffraction grating 50, and the image sensor 70 are not shown, but are provided in a spectroscope chamber evacuated by a vacuum pump and scanned via a gate valve. It shall be attached to the barrel of a scanning electron microscope. Further, the adjusting members 42a, 42c, 42b, and 42d may be provided in the spectroscope chamber exhausted by a vacuum pump, or can be adjusted from the outside of the spectroscopic chamber through an operation member such as a rod. It is.

  Further, details of the configuration of the diffraction grating 50 and its periphery in this X-ray detection system are described in Japanese Patent Application Laid-Open No. 2002-329473, to which the applicant of the present application separately applied. Further, since a known system for processing a diffracted X-ray obtained by the image sensor 70 can be used, detailed description thereof is omitted.

  FIG. 3 shows a case where the X-ray condensing mirrors 34a and 34b are linearly configured.

  In FIG. 3A, the mirrors 34a and 34b are adjusted in their positions or angles by adjusting members 42a to 42d controlled by the X-ray focusing mirror adjustment control unit 41. The X-ray focusing mirrors 34a and 34b are in the initial state or A specific example in the neutral state is shown. Here, it is assumed that X-rays detected in the X-ray detection system have intermediate energy compared to the case described later.

  Here, an example of the locus of X-rays reflected from the sample 20 by the X-ray collector mirrors 34 a and 34 b is shown, and a large number of reflected light and direct light not shown here are incident on the diffraction grating 50. Yes.

  Here, when the X-ray detected in the X-ray detection system becomes higher energy than in the case of FIG. 3A, the analysis unit 80 that analyzes this high-energy X-ray is in high energy processing. This is notified to the X-ray condenser mirror adjustment control unit 41.

  The X-ray focusing mirror adjustment control unit 41 that has received the notification of the high energy processing performs control such that the adjustment members 42a and 42c are extended and the adjustment members 42b and 42d are compressed. As a result, the distance between the X-ray condenser mirrors 34a and 34b on the sample 20 side is narrowed and the distance on the diffraction grating 50 side is widened. This state is shown in FIG. In FIG. 3B, for comparison, the positions of the X-ray focusing mirrors 34a and 34b in FIG. 3A are indicated by thin broken lines. In the case of FIG. 3B, the X-ray condensing mirrors 34a and 34b increase the incident angle of X-rays reflected at the same position as in FIG. 3A, thereby reflecting high-energy X-rays. It becomes possible to respond.

  That is, since the critical angle that can be reflected increases as the X-rays become higher energy, the X-rays with higher energy cannot be reflected if they remain as shown in FIG. 3A, but are incident as shown in FIG. 3B. Increasing the angle causes high energy X-rays to be reflected.

  The incident angle means an angle formed between the incident direction and the normal of the reflecting surface at that point when entering the reflecting surface. The critical angle is the minimum incident angle that causes total reflection beyond the incident angle.

  Since the incident sides of the X-ray condensing mirrors 34a and 34b are narrowed, the condensing efficiency is slightly lowered. Therefore, it is desirable to determine the angle to be adjusted according to the degree of X-ray energy.

  On the other hand, when the X-ray detected in the X-ray detection system has a lower energy than in FIG. 3A, the analysis unit 80 for analyzing the low-energy X-ray is in a low energy process. Is sent to the X-ray condenser mirror adjustment control unit 41.

  The X-ray focusing mirror adjustment control unit 41 that has received this low energy processing notification performs control to compress the adjustment members 42a and 42c and extend the adjustment members 42b and 42d. As a result, the distance between the X-ray condenser mirrors 34a and 34b on the sample 20 side is widened and the distance on the diffraction grating 50 side is narrowed. This state is shown in FIG. In FIG. 3C, the positions of the X-ray condensing mirrors 34a and 34b in FIG. 3A are indicated by thin broken lines for comparison. In the case of FIG. 3C, the X-ray condensing mirrors 34a and 34b reduce the incident angle of X-rays reflected at the same position as in FIG. 3A, thereby reflecting low-energy X-rays. It will be in a suitable state.

  In other words, the critical angle that can be reflected decreases as the X-ray energy becomes lower. In this case, low-energy X-rays can be reflected even if the state shown in FIGS. 3A and 3B is maintained, but condensing efficiency is improved by widening the incident side as shown in FIG. 3C. Also, there is an advantage that high energy X-rays that are not to be processed are not reflected.

  It should be noted that adjusting the positions and angles of the X-ray focusing mirrors 34a and 34b changes from the initial angle in FIG. 3A, and hence the aberration caused by the X-ray focusing mirrors 34a and 34b increases. Since the resolution of the energy distribution spectrum may be lowered, the analysis unit 80 and the X-ray focusing mirror adjustment control unit 41 make necessary adjustments according to the difference in X-ray energy and the request for resolution.

  As described above, the X-ray collector mirror adjustment unit 40 adjusts the incident angle of the characteristic X-rays to the X-ray collector mirrors 34a and 34b to be large when the energy of the characteristic X-rays is large. When the energy of the X-ray is small, by adjusting the incident angle of the characteristic X-ray to the X-ray collector mirror to be small, the X-ray collector mirror can be reflected at each energy of the X-ray. The optical mirror can collect light appropriately according to the energy of the X-ray, and can maintain the detection accuracy of the energy distribution spectrum.

  The X-ray collector mirror adjustment unit 40 adjusts the position or angle of the X-ray collector mirrors 34a and 34b in a direction orthogonal to the energy dispersion direction of the diffracted X-ray image, thereby diffracted X-ray image. The X-ray collector mirror is able to reflect the X-ray energy at each angle so that the X-ray collector mirror can collect light appropriately according to the energy of the X-ray. It becomes possible to maintain the detection accuracy of the spectrum.

Second Embodiment
FIG. 3 shows the case where the X-ray condensing mirrors 34a and 34b are configured in a straight line. However, in order to increase the condensing efficiency, as shown in FIG. It is also possible to have a reflecting surface composed of a curved surface of the combination. However, since the curvature of the curved surface that is optimal varies depending on the energy of the X-rays to be used, the curvature of the curved surface is determined in accordance with the intermediate energy X-rays, and then shown in FIGS. As shown in c), it is desirable to adjust the positions or angles of the X-ray focusing mirrors 34a and 34b.

<Third Embodiment>
FIG. 4 shows the case where the X-ray condensing mirrors 34a and 34b are formed of curved surfaces. However, in order to realize the approximation of the curved surface according to the energy of the X-ray, as shown in FIG. The X-ray collector mirror 34a on the first side is configured with two X-ray collector mirrors 34a1 and 34a2, and the X-ray collector mirror 34b on the other side is configured with two X-ray collector mirrors 34b1 and 34b2. It is possible.

  Then, adjustment members 42a1 and 42a2 for adjusting the X-ray collector mirror 34a1, adjustment members 42b1 and 42b2 for adjusting the X-ray collector mirror 34a2, adjustment members 42c1 and 42c2 for adjusting the X-ray collector mirror 34b1, and an X-ray collector Adjustment members 42d1 and 42d2 for adjusting the optical mirror 34b2 are provided, and control is performed from the X-ray focusing mirror adjustment control unit 41.

  In this case, the X-ray condenser mirror adjustment control unit 41 gives instructions to the adjustment members 42a1, 42a2, 42c1, and 42c2, and when the characteristic X-ray energy is large, the characteristic X for the X-ray condenser mirrors 34a1 and 34b1 Adjustment is made so that the incident angle of the line becomes large, and when the energy of the characteristic X-ray is small, adjustment is made so that the incident angle of the characteristic X-ray with respect to the X-ray collector mirror becomes small.

  The X-ray collector mirror adjustment control unit 41 adjusts the adjustment member 42b1 in conjunction with the adjustment member 42a2 so that the adjacent end portions of the X-ray collector mirrors 34a1 and 34a2 coincide with each other. 42d1 is adjusted in conjunction with the adjustment member 42c2 so that the adjacent end portions of the X-ray focusing mirrors 34b1 and 34b2 coincide.

  Then, the X-ray focusing mirror adjustment control unit 41 gives an instruction to the adjustment members 42b2 and 42d2 and performs adjustment so that the above-described reduction in resolution can be suppressed according to the energy of the characteristic X-rays.

  As described above, the X-ray collector mirrors 34a1, 34a2, 34b1, and 34b2 have angles that can be reflected by the X-ray energy, and the X-ray collector mirrors correspond to the X-ray energy. Appropriate focusing can be performed, and the detection accuracy of the energy distribution spectrum can be maintained. That is, it is possible to realize the control of the incident angle at the time of reflection corresponding to the energy of X-rays (FIG. 3) and the approximation of the optimum curved surface according to the energy of X-rays to be used.

  FIG. 5 shows a specific example in which the X-ray collector mirrors 34a and 34b are each divided into two pieces. However, even when the X-ray collector mirrors 34a and 34b are divided more than this, the X-ray collector mirror adjustment unit 40 is similarly divided. Thus, each X-ray condensing mirror can perform appropriate condensing according to the energy of X-rays, and can maintain the detection accuracy of the energy distribution spectrum.

  Further, the X-ray condensing mirrors 34a and 34b are each composed of a flexible thin plate, and a large number of adjusting members are arranged so that the incident side is a hyperbolic function and the exit side is a parabolic function control. It is also possible to control to an optimum shape according to energy. In this case, although the number of parts increases, it becomes possible to control to a desired reflecting surface shape.

<Fourth embodiment>
By the way, it is assumed that the diffraction X-ray image on the light receiving surface of the image sensor 70 is formed as shown in FIG. It is assumed that the energy distribution spectrum as an analysis result in the analysis unit 80 in this state is displayed as shown in FIG.

  Here, if the one end of the X-ray condensing mirrors 34a and 34b is excessively narrowed by the control as shown in FIG. 3B and the condensing efficiency is lowered, the light receiving surface of the image sensor 70 as shown in FIG. A part of the diffracted X-ray image may disappear at the end in the X direction. An energy distribution spectrum as an analysis result in the analysis unit 80 in this state is as shown in FIG. 6D, and the peak level is lower than that in FIG.

  Therefore, when the adjustment amount is changed by the X-ray condenser mirror adjustment unit 40, the analysis unit 80 can detect a reduction in the light collection efficiency by monitoring the change in the peak value of the energy distribution spectrum. is there. Note that the analysis unit 80 can also perform image processing on the diffracted X-ray image on the light receiving surface of the image sensor 70 to recognize whether or not a disappeared portion has occurred in the diffracted X-ray image. Therefore, the analysis unit 80 and the X-ray collector mirror adjustment unit 40 cooperate with each other in the range where the light collection efficiency does not decrease, or at the time of reflection corresponding to the above-described X-ray energy within the minimum reduction of the light collection efficiency. It is desirable to control the incident angle.

  On the other hand, when the incident side of the X-ray condensing mirrors 34a and 34b is widened by the control as shown in FIG. 3 (c) or excessively condensed by narrowing the exit side, as shown in FIG. 6 (e). In addition, on the light receiving surface of the image sensor 70, a dark band (fogging) region in the Z direction may occur near the center in the X direction. In this case, since the S / N ratio is reduced as a whole in the image received by the image sensor 70, the resolution of the energy distribution spectrum may be reduced.

  Therefore, when the adjustment amount is changed by the X-ray condenser mirror adjustment unit 40, the analysis unit 80 performs image processing on the diffraction X-ray image on the light receiving surface of the image sensor 70, and the disappearance portion is included in the diffraction X-ray image. It is also possible to recognize an image of whether it has occurred. Therefore, the analysis unit 80 and the X-ray collector mirror adjustment unit 40 cooperate to control the incident angle at the time of reflection corresponding to the X-ray energy as long as a dark band in the Z direction does not occur. It is desirable.

  Further, by adjusting the positions and angles of the X-ray condensing mirrors 34a and 34b, the aberration caused by the X-ray condensing mirrors 34a and 34b becomes large when there is a large change from the initial angle in FIG. There is a case. When the aberration caused by the X-ray condensing mirrors 34a and 34b increases, a Fermi edge linear in the X direction as shown in FIG. ) Is a distorted Fermi edge. Due to such a distorted Fermi edge, the peak resolution of the energy distribution spectrum is lowered.

  Therefore, when the adjustment amount is changed by the X-ray collector mirror adjustment unit 40, the analysis unit 80 causes the sharpness of the rising edge of the edge portion of the energy distribution spectrum (inclination in the vertical direction in FIGS. 7C and 7D). By monitoring this, it is possible to discover whether aberration has occurred. Note that the analysis unit 80 can also perform image processing on the diffraction X-ray image on the light receiving surface of the image sensor 70 to recognize the image component ratio between the X direction and the Y direction of the edge in the diffraction X-ray image. is there. Therefore, the analysis unit 80 and the X-ray condenser mirror adjustment unit 40 correspond to the above-described X-ray energy within a range where the Fermi edge is not distorted or within a range where the Fermi edge can be distorted. It is desirable to control the incident angle during reflection.

<Fifth Embodiment>
By adjusting the positions and angles of the X-ray condensing mirrors 34a and 34b as described above, various aberrations occur, or interference light such as CL (cathode luminescence) light is reflected and diffracted. The lattice 50 may be reached. As a result, by adjusting the positions and angles of the X-ray condensing mirrors 34a and 34b as described above, the influence of aberration and interference light may appear greatly, and the resolution of the energy distribution spectrum may deteriorate. In such a case, the position and angle of the X-ray condensing mirrors 34a and 34b are adjusted so that aberration is not generated or interference light is not reflected so that the analyzing unit 80 and the X-ray condensing mirror adjustment control are performed. It is desirable for the part 41 to adjust.

  For example, as shown in FIG. 8A, by adjusting the X-ray condensing mirrors 34a and 34b in a direction parallel to the spread of the characteristic X-rays from the sample 20, characteristic X-rays and interference light are reflected. Disappears.

  Alternatively, as shown in FIG. 8B, the characteristic X-rays and interference light are reflected by adjusting the direction so that the incident angle of the characteristic X-rays with respect to the X-ray condensing mirrors 34a and 34b is equal to or greater than the critical angle. Disappear. Further, even if characteristic X-rays or interference light partially reflected near the ends of the X-ray collector mirrors 34a and 34b are present, the X-ray collector mirrors 34a and 34b are oriented in such a direction that they do not face the diffraction grating 50. Adjust.

  In addition, even if the orientation is not adjusted to the extreme direction as shown in FIGS. 8A and 8B, the resolution is lowered due to the influence of aberration or interference light while adjusting from the orientation of FIG. 3 to the orientation of FIG. It is desirable that the analysis unit 80 and the X-ray focusing mirror adjustment control unit 41 adjust so that the position and angle disappear.

<Sixth Embodiment>
In the above configuration, there is an X-ray detection system in which a plurality of different diffraction gratings can be exchanged according to the energy value, the material of the sample 20, the energy of characteristic X-rays, and the like. In the case of FIG. 9, a plurality of different diffraction gratings 50 a and 50 b on the turntable 51 that rotate in response to an instruction from the analysis unit 80 are selectively used.

  In this case, the analysis unit 80 adjusts the positions or angles of the X-ray focusing mirrors 34a and 34b according to the characteristic X-ray energy corresponding to each of the plurality of different diffraction gratings 50a / 50b. The adjustment value data is stored, the stored adjustment value is read out according to the diffraction grating 50a / 50b to be used, and the adjustment value is notified to the X-ray focusing mirror adjustment control unit 41. As a result, the positions and angles of the X-ray focusing mirrors 34a and 34b are automatically adjusted in accordance with the X-ray energy corresponding to the diffraction grating 50a / 50b. By executing the automatic adjustment according to the diffraction gratings 50a / 50b as a rough adjustment and then performing the adjustment described with reference to FIGS. Accordingly, it is possible to quickly perform appropriate light focusing according to a wide range of the above, and to maintain the detection accuracy of the energy distribution spectrum.

  In the case of FIG. 9, when the generation of CL light or the like is predicted according to the type of the diffraction grating 50, the angle at which reflection is not performed as shown in FIG. 8 may be stored in advance. . In this way, measurement without failure is possible.

DESCRIPTION OF SYMBOLS 10 Electron beam irradiation part 20 Sample 30 X-ray condensing mirror part 40 X-ray condensing mirror adjustment part 50 Diffraction grating 70 Image sensor 80 Analysis part 90 Display part

Claims (7)

An electron beam irradiation unit for irradiating the sample with an electron beam;
An X-ray condenser mirror that condenses characteristic X-rays emitted from the sample irradiated with the electron beam and guides it to a diffraction grating;
An X-ray collector mirror adjustment unit for adjusting the position or angle of the X-ray collector mirror;
A diffraction grating that receives characteristic X-rays collected by the X-ray focusing mirror and generates diffracted X-rays;
An image sensor for detecting diffracted X-rays generated by the diffraction grating;
With
The X-ray collector mirror adjustment unit adjusts the position or angle of the X-ray collector mirror within an angle range that can be reflected according to the energy of the characteristic X-ray reflected on the reflection surface of the X-ray collector mirror. To
X-ray detection system characterized by the above. The X-ray collector mirror adjustment unit adjusts an incident angle of the characteristic X-ray with respect to the X-ray collector mirror when the energy of the characteristic X-ray is large, and the energy of the characteristic X-ray is small In this case, the incident angle of the characteristic X-ray with respect to the X-ray collector mirror is adjusted to be small.
The X-ray detection system according to claim 1. The X-ray collector mirror adjustment unit adjusts the position or angle of the X-ray collector mirror in a direction orthogonal to the energy dispersion direction of the image of the diffracted X-ray;
The X-ray detection system according to claim 1-2. An analysis unit that generates an energy distribution spectrum by analyzing the diffracted X-rays detected by the image sensor;
The X-ray collector mirror adjustment unit adjusts the position or angle of the X-ray collector mirror so that the intensity of any spectral component included in the energy distribution spectrum is increased.
The X-ray detection system according to claim 1, wherein the system is an X-ray detection system. An analysis unit that generates an energy distribution spectrum by analyzing the diffracted X-rays detected by the image sensor;
The X-ray focusing mirror adjustment unit may detect a decrease in resolution or a peak level in any spectral component included in the energy distribution spectrum according to a critical angle determined by the energy of the characteristic X-ray. Adjusting the position or angle of the X-ray collector mirror so as to exclude the range of angles that can be reflected;
The X-ray detection system according to claim 1, wherein the system is an X-ray detection system. An analysis unit that generates an energy distribution spectrum by analyzing the diffracted X-rays detected by the image sensor;
The X-ray collector mirror adjustment unit adjusts the position or angle of the X-ray collector mirror within a range in which the decrease is eliminated;
The X-ray detection system according to claim 5, wherein: An X-ray detection system configured such that a plurality of different diffraction gratings determined according to the energy of the characteristic X-ray can be exchanged,
The X-ray collector mirror adjustment unit adjusts data for adjusting the position or angle of the X-ray collector mirror according to the characteristic X-ray energy corresponding to each of a plurality of different diffraction gratings. , And read and adjust the adjustment value stored according to the diffraction grating used,
The X-ray detection system according to any one of claims 1 to 6, wherein: