JP3451608B2 - X-ray analyzer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray analyzer such as an electron beam microanalyzer, and more particularly to a composition mapping for performing two-dimensional analysis of a sample surface by scanning a stage.
A surface shape mapping representing a surface shape of a sample surface. 2. Description of the Related Art In an X-ray analyzer, for example, in an electron beam microanalyzer, a sample surface is two-dimensionally scanned with an electron beam to ionize the atoms of the sample, and a characteristic X generated at that time is generated.
Measurement of distribution of component elements and the like is performed by detecting secondary radiation such as a line. Such an apparatus is usually provided with an optical microscope for adjustment between the electron optical system and the X-ray optical system, confirmation of the analysis position on the sample surface, and the like. A sample stage capable of fine movement with an accuracy of about μm is provided. In order to cope with the analysis of the micro area of a large sample, the sample stage is automatically scanned in the X and Y directions to perform mapping by a wide area surface analysis, and to cope with the undulation and unevenness of the sample surface. In order to adjust the focus position of the X-ray spectroscope, the sample stage is moved in the Z-axis direction by an automatic focusing device provided in an optical microscope for observing an optical image of the sample surface. Thus, a two-dimensional surface analysis result is created as a composition map even for a large sample. FIG. 7A shows an example of a composition map, in which a composition and a two-dimensional distribution thereof are obtained based on a characteristic X-ray intensity distribution obtained from a sample and are displayed two-dimensionally. [0005] In the conventional X-ray analyzer, two-dimensional composition distribution can be observed.
There is a problem that three-dimensional observation including the surface shape of the sample cannot be simultaneously performed by one apparatus, and that display on the same map cannot be performed. In sample observation, information on the surface shape of the sample such as undulations and irregularities may be required in addition to information on the composition distribution of the sample. This surface shape is obtained by an observation means different from an X-ray analyzer such as observation of backscattered electrons such as BSE.
A surface shape map as shown in (b) is formed and two-dimensionally represented. Therefore, when information on both the composition distribution and the surface shape of the sample is required, the composition map and the surface shape map separately obtained are displayed side by side, and the data are compared and compared. [0007] Therefore, it is necessary to separately prepare an apparatus for the composition distribution and an apparatus for the surface shape, and it is not possible to obtain both data simultaneously, and it is not possible to perform analysis and observation in parallel. . Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional X-ray analyzer and to provide an X-ray analyzer capable of simultaneously obtaining composition data and shape data with one apparatus. It is another object of the present invention to provide an X-ray analyzer capable of displaying composition data and surface shape data on the same map. In the X-ray analyzer of the present invention, an electron beam irradiator, an X-ray spectroscope for detecting X-ray intensity, and a sample stage are automatically scanned in X and Y directions. By using a configuration including an X, Y stage device and a Z stage device that makes the sample surface follow the focal position of the X-ray spectrometer in the Z direction, the composition data of the sample is obtained from the X-ray intensity,
By obtaining the surface shape data of the sample from the stage device and the Z stage device, the composition data and the surface shape data are obtained simultaneously by one device. Further, the present invention includes a data processing device, and forms a three-dimensional map based on the composition data of the sample obtained from the X-ray intensity and the surface shape data of the sample obtained from the X, Y stage device and the Z stage device. A data processing device is provided. With this data processing device, the composition data and the surface shape data can be displayed on the same map. An X, Y stage apparatus according to the present invention controls an X, Y stage that directly moves a sample stage, an X, Y stage driving device that drives the X, Y stage, and controls the X, Y stage driving device. A series of mechanisms including an X and Y stage control unit. The surface shape data of the sample in the X and Y directions is coordinate data relating to the X and Y stage devices (for example, a movement amount, a control signal, etc. obtained from each device). ). Further, the Z stage apparatus of the present invention is a mechanism for moving the sample stage in the Z direction so that the position of the sample surface is always maintained at the focal position of the X-ray spectrometer, and the sample stage is directly moved. A series including a Z stage to be driven, a Z stage driving device for driving the Z stage, a Z stage control device for controlling the Z stage driving device, and a mechanism for detecting position information of a sample surface and feeding back the information to the Z stage control device The surface shape data of the sample in the Z direction can be obtained from coordinate data (for example, the movement amount and control signals from each device) related to the Z stage device. Further, the data processing apparatus of the present invention forms a three-dimensional map consisting of a set of composition data and surface shape data at the same analysis point of the same sample from the composition data and the surface shape data of the sample. Are superimposed and image-processed and displayed on the same map. In the first embodiment of the present invention, the mechanism for detecting the position information of the sample surface in the Z stage controller and feeding it back to the Z stage controller is provided in an optical microscope for observing an optical image of the sample surface. This is an automatic focusing device, and the surface shape data of the sample in the Z direction can be obtained from the movement amount in the Z axis direction by the automatic focusing device. According to a second embodiment of the present invention, a data processing device includes a storage device for storing composition data and surface shape data subjected to image processing, and stores the storage device in a display device in parallel with the image processing of the data. By transmitting the data, real-time display is possible, and by transmitting data from the storage device to the display device collectively, the entire analysis area can be displayed off-line. The sample stage is automatically scanned in the X and Y directions by the X and Y stage devices to match the electron beam irradiation point with the sample analysis point. On the other hand, the Z stage device moves and follows the sample stage in the Z direction according to the unevenness of the sample surface so that the sample surface is at the focal position of the X-ray spectrometer. Then, surface shape data of the sample is obtained from the X and Y coordinates obtained as the X and Y stage devices move and the Z coordinates obtained as the Z stage device moves. Further, in collecting the composition data of the sample, the analysis point is irradiated with an electron beam from an electron beam irradiation apparatus, and characteristic X-rays emitted from the analysis point are detected by an X-ray spectrometer. The measurement is performed by measuring the X-ray intensity of the characteristic X-ray. The collection of the surface shape data and the composition data can be performed simultaneously for the same sample with the same measurement. Further, the data processing device forms data of a three-dimensional map based on the composition data and the surface shape data of the sample, and displays the data on a three-dimensional map on a display device. This three-dimensional map displays composition data and surface shape data on the same map, and allows different-dimensional data to be checked at a glance without comparing and comparing two maps as in the related art. . Embodiments of the present invention will be described below in detail with reference to the drawings. (Configuration of Embodiment of the Present Invention) A configuration example of an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating the configuration of an embodiment of the X-ray analyzer according to the present invention. In FIG. 1, an electron beam irradiation apparatus 1 includes an electron gun, an electron lens, and the like, and forms an irradiation spot by an electron beam on an analysis point on the surface of a sample S.
The characteristic X-ray generated from the sample surface by the electron beam is detected by the X-ray analyzer 2 including the spectral crystal 21 and the X-ray detector 22. The scanning of the sample S in the X and Y directions is performed by controlling the sample stage 3 in the X and Y directions by the X and Y stage device 4. The X, Y stage device 4 includes an X, Y stage 41 for directly moving the sample stage 3, and an X, Y
X, Y stage driving device 42 for driving stage 41,
And an X, Y stage control device 43 for controlling the X, Y stage drive device 42. The X and Y stage control device 43 sends a scanning signal in the X and Y directions to the X and Y stage driving device 42 to drive the X and Y stage 41. The alignment of the analysis point of the sample S with the focal position of the X-ray spectrometer 2 is performed by controlling the sample stage 3 in the Z direction by following the surface shape of the sample S by the Z stage device 5. Done. The Z stage device 5 includes a Z stage 51 that directly moves the sample stage 3, a Z stage drive device 52 that drives the Z stage 51, and a Z stage control device 5 that controls the Z stage drive device 52.
3, and an autofocus device 54 that performs feedback so that the sample surface is always kept at the focal position of the X-ray spectrometer. The autofocus device 54 is provided in the optical microscope 6 for observing an optical image of the sample S in the X-ray analyzer, and is a mechanism for matching the focal position of the X-ray spectroscope 2 with the analysis point of the sample S. . In the X-ray analyzer of the present invention, the automatic focusing device 54 is used not only as a mechanism for focusing but also as a mechanism for acquiring surface shape data of the sample S. The X-ray intensity of characteristic X-rays obtained from the X-ray spectroscope 2, the X and Y coordinate data from the X and Y stage controller 43, and the data related to the Z coordinate obtained from the automatic focusing device 54 are data. Input to the processing device 7. The data processing device 7 performs image processing based on the input data, forms a three-dimensional map including X, Y, and Z coordinate data and composition data, and stores the map in a storage unit. The display device 8 reads the data of the three-dimensional map stored in the storage means, and displays the composition data and the surface shape data on the same map. (Operation of Embodiment of the Present Invention) Next, the operation of the embodiment of the present invention will be described with reference to FIGS. The operation of the X-ray analyzer of the present invention can be performed according to the flowchart shown in FIG. Hereinafter, a case will be described in which composition analysis is performed at analysis points P0, P1,... On the scanning line on the sample surface, and the surface shape at this position is detected. When scanning is started from the reference point P0 on the scanning line, first, the X, Y coordinates (x0, y0) of the reference point P0 are read from the X, Y stage controller 43 (step S1), and the X, Y stage is driven. By driving the device 42 and the X, Y stage 41, the irradiation position of the electron beam and the reference point P
0 is matched (step S2). Next, at the reference point P0, the Z-stage controller 5
3. The Z-stage driving unit 52 and the Z-stage 51 are driven to perform Z-axis positioning (step S).
3). The data processing device 7 inputs the coordinate position in the Z-axis direction before the automatic focusing operation from the Z-stage control device 53 as a reference position, and the coordinate position and the movement amount Δz in the Z-axis direction by the automatic focusing operation in step S3. In addition, the coordinate z from the reference position in the Z-axis direction is determined as z0. In addition,
An arbitrary value obtained by adding a bias value to the value of the coordinate position in the Z-axis direction before the automatic focusing operation can be set as the reference position (step S4). An index n for determining an analysis point in scanning is determined, and "1" representing the first analysis point is set (step S).
5). The analysis point P from the X, Y stage controller 43
Read the X, Y coordinates (xn, yn) of n (step S
6), the X, Y stage 41 is driven and the coordinate position (xn,
yn, zn-1). For example, when the value of the index n is “1”, the movement to the coordinate position (x1, y1, z0) is performed (step S7). The coordinate position (xn, yn, zn-1) is used as a tentative coordinate position of the analysis point Pn. At this position, the X-ray intensity of the characteristic X-ray from the X-ray spectroscope 2 is detected, and the data processor 7 To obtain analysis data (step S8). Next, the coordinate position (xn, yn, zn-
In 1), the Z stage 5 is
1 is driven to perform an automatic focusing operation to perform positioning in the Z-axis direction (step S9). The data processing device 7 inputs the movement amount Δz associated with the positioning in the Z-axis direction (step S10), and updates the Z coordinate zn as zn = zn + Δz (step S11). Using the updated Z coordinate zn, the coordinate position (x
n, yn, zn-1) to (xn, yn, zn),
The coordinate position (xn, yn, zn) is stored in the storage means as surface shape data together with the analysis data obtained in step S8. The form of the analysis data at the time of storage may be any of data before image processing, data after image processing, and data before and after image processing. When displaying in real time, the processing time can be reduced by storing the data after the image processing (step S12). The steps S6 to S12 are repeated while the index n is sequentially increased until the scanning is completed (steps S13 and S14). The collection of the analysis data in step S8 can be performed between step S9 and step S12. When the analysis data is collected in step S8, image processing of the obtained analysis data can be performed during the automatic focusing operation after this step,
Real-time display processing becomes easy. When the analysis data is collected between step S9 and step S12, the analysis data can be collected at a more accurate focal position. FIG. 3 is a view for explaining a procedure for obtaining data in the Z-axis direction by the automatic focusing operation in the step S10. The broken line indicates the position of the sample in the (i) -th scanning order, and the solid line indicates the position of the sample in the (j) -th scanning order. In the (i) -th sample, the focus of the electron beam is assumed to be aligned with the analysis point (Pi). The sample is moved by the arrow a by scanning.
When the analysis is performed at the analysis point (Pj) by moving in the direction of, the focal point of the electron beam and the analysis point (Pj) do not coincide with each other due to unevenness of the sample surface. Therefore, the sample is moved in the Z-axis direction of the arrow b by the automatic focusing operation, so that the focus of the electron beam coincides with the analysis point Pj. In this automatic focusing operation, the amount of movement Δz moved in the Z-axis direction is the height difference between the analysis points Pi and Pj on the sample surface. By calculating the height difference on the sample surface, the surface shape data of the sample can be obtained. Obtainable. FIGS. 4 and 5 show scanning in the X and Y directions and Z scanning.
It is a figure explaining the relation with the movement of the direction. In this embodiment, when moving to the analysis point Pn, the X and Y coordinates (xn, yn) of the analysis point Pn are used for the X and Y coordinates.
The Z coordinate is estimated based on the Z coordinate (zn-1) value of the previous analysis point Pn-1. As shown in FIG. 4, when scanning and analysis are sequentially performed from the analysis point P0 to the analysis point P5 along one scanning line on the sample surface, the procedure is as shown in FIG. In FIG. 5, the movement from the analysis point P0 to the analysis point P1
(X0,
y0) to (x1, y1) (x in the figure)
mark). Next, the sample is moved in the Z-axis direction by an automatic focusing operation, and the (Z0 + Δz1) obtained by adding the Z coordinate z0 of the analysis point P0 to the movement amount Δz1 at that time is defined as the Z-axis coordinate z1 of the analysis point P1. Next, the movement from the analysis point P1 to the analysis point P2 is performed in the X and Y directions (x
From (1, y1) to (x2, y2), the sample is moved in the Z-axis direction by the automatic focusing operation, and the Z coordinate z1 of the analysis point P1 is added to the movement amount Δz2 at that time (z1 + Δ).
z2) is the Z-axis coordinate z2 of the analysis point P2. Hereinafter, similarly, the movement to the analysis points P3, P4, and P5 and the detection of the Z-axis coordinates can be performed. FIG. 6 shows an example of a three-dimensional map of the composition data and the surface shape data obtained by the data processing device 7. The composition data indicated by A to D in the figure can be displayed by, for example, color coding and the like, and the surface shape data can be represented by contour lines and cross-sectional views. As described above, according to the present invention,
An X-ray analyzer capable of simultaneously obtaining composition data and shape data with a single device can be provided. Also,
An X-ray analyzer capable of displaying composition data and surface shape data on the same map can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of an embodiment of an X-ray analyzer according to the present invention. FIG. 2 is a flowchart for explaining the operation of the X-ray analyzer of the present invention. FIG. 3 is a diagram illustrating a procedure for obtaining data in the Z-axis direction by an automatic focusing operation according to the present invention. FIG. 4 is a diagram illustrating the relationship between scanning in the X and Y directions and movement in the Z direction according to the present invention. FIG. 5 is a diagram illustrating the relationship between scanning in the X and Y directions and movement in the Z direction according to the present invention. FIG. 6 is an example of a three-dimensional map of composition data and surface shape data displayed by the device of the present invention. FIG. 7 is a conventional composition map example and surface shape map example. [Description of Signs] 1 ... electron beam irradiation device, 2 ... X-ray spectroscope, 3 ... sample stage, 4 ... X and Y stage device, 5 ... Z stage device, 6 ... optical microscope, 7 ... data processing device, 41 ... X,
Y stage, 42 ... X, Y stage driving device, 43 ...
X, Y stage controller, 51 ... Z stage, 52 ... Z
Stage drive device, 53 ... Z stage control device, 54 ...
Autofocus device, S: sample.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 23/00-23/227 H01J 37/252-37/295 G01B 11/00-11/30 102

Claims (1)

(57) [Claims 1] An electron beam irradiation apparatus, an X-ray spectroscope for detecting X-ray intensity, and an X and Y stage apparatus for automatically scanning a sample stage in X and Y directions. A Z stage device that makes the sample surface follow the focal position of the X-ray spectrometer in the Z direction, composition data of the sample obtained from the X-ray intensity, and surface shape data of the sample obtained from the X, Y stage device and the Z stage device An X-ray analysis apparatus comprising: a data processing device that forms a three-dimensional map by using the data processing device.