JPH01166447A - Surface analysis mapping device - Google Patents

Abstract

PURPOSE:To reduce a time required for by deciding a scanning range automatically in a process of mapping instead of setting a scanning area previously so as not to scan the area where there is no sample. CONSTITUTION:As electron pulse microanalyzer(EPMA) is composed of an electron gun 1, the objective lens 2 of an electron optics system, a sample stage 3, a moving device 4 in the X, Y and Z axis directions, a spectral crystal 5 and a X-ray detecting unit 6 and the like. An automatic focusing detecting means 11 is provided in an optical microscope attached to this EPMA, and whether an electron beam irradiation point is on a sample S surface or not is distinguished by whether a sample S surface is detected in a defined range in the optical axis direction or not at the time of scanning the sample S surface, and the scanning direction is inverted where a state that the sample S surface is detected changes to a state that it is not detected. With this arrangement, a scanning range is automatically decided in compliance with the form of the sample, and a useless range is not scanned, and thereby a required time for mapping is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an apparatus for two-dimensionally analyzing a sample surface using an electron beam microanalyzer (EPMA).

Two-dimensional analysis (matuping) of the sample surface using the conventional technique EPMA
Conventionally, when performing analysis, a rectangular scanning area was set on the sample surface. In this method of setting the scanning area to a rectangle, if the shape of the sample is irregular, such as when mapping the entire cross section of a given product, the scanning area can be set to a rectangle that circumscribes the shape of the sample. Therefore, time is consumed for scanning even parts of the region where no sample is present, and the time required for analysis is long relative to the sample area.

C.9 Problems to be solved by the invention When mapping irregularly shaped samples, conventionally a scanning area was set that encompasses the sample, but it is extremely complicated to set the scanning area in advance to match the shape of the sample. This is because it is work. Therefore, in the present invention, the scanning area is set in advance (,
The aim is to automatically determine the scanning range during the mapping process.

21 Means for Solving Problems The optical microscope attached to the EPMA is equipped with automatic focus detection means, and during sample surface scanning, the electronic beam The system identifies whether the irradiation point is on the sample surface or off the sample surface, and the scanning direction is reversed when the sample surface changes from being detected to not being detected.

The optical axis of the optical microscope attached to the E-8 action EPMA is aligned with the optical axis of the electron optical system. Assuming that the two directions orthogonal to the optical axis are the X and Y directions, and the optical axis direction is the two directions, the position of the sample surface in the Z direction can be determined by moving the sample surface in the Z direction so that the focus of the optical microscope is on the sample surface. In other words, the height can be set at a predetermined position. When the sample surface is moved in both the X and Y directions and the sample surface is scanned by the electron beam, if the sample surface deviates from the optical axis of the optical microscope, the focus detection device will generate an out-of-focus signal and the optical axis of the electron optical system will be It can be seen that it has come off the sample surface. Therefore, if the scanning direction is reversed when the state changes from in-focus to out-of-focus, scanning will always be performed within the range that extends beyond the outer shape of the sample, and the scanning range will automatically change. It is determined according to the shape of the sample, and since there is no need to scan unnecessary areas, the time required for mapping is shortened.

Embodiment FIG. 1 shows an embodiment of the present invention. 1 is the electron gun, 2 is the objective lens of the electron optical system, 3 is the sample stage, X, Y3
It is mounted on the axial moving device B4, and S is the sample placed on the sample stage. 5 is a spectroscopic crystal that separates X-rays emitted from the electron beam irradiation point on the sample surface;
Reference numeral 6 denotes an X-ray detector, and the above-mentioned parts constitute an EPMA.

7 is an objective concave mirror of an optical microscope attached to the EPMA, and its optical axis is aligned with the optical axis of the electron optical system. The optical axis of the optical microscope is bent laterally by a mirror 8 so that an image of the sample surface by an objective concave surface j; 17 is formed on the light receiving surface of the image pickup elements 9, 9'. Image sensor 9, 9
゛ is when the sample surface is at the normal height on the optical axis of the optical microscope.
They are arranged on opposite sides of the optical axis in front and behind the image I of the sample surface when it is at the axially inner position wl). Reference numeral 10 denotes a semi-transparent mirror. Regarding this semi-transparent mirror, a point light source is arranged at a position conjugate to the image position I on the sample surface, and the image of this L is formed on the sample surface by the objective concave mirror 7.

The light from the light source projected onto the sample surface is reflected by the sample surface, forming an image of the projected spot of the light from the light source on the sample surface at an image I on the sample surface. When the sample surface is at the normal height, the image of this spot is! The spot image is slightly blurred and widened at the image pickup devices located before and after the position I. As the height of the sample surface decreases, the image of the spot approaches the image sensor 9, and the light receiving range of the image sensor 9 becomes wider than that of the image sensor 9'. The light receiving range of the image sensor 9' is 9
wider than that of The focus detection device 11 includes an image sensor 9,
The light receiving range of 9" is monitored, and if the light receiving range of 9" is larger, a signal is sent to raise the sample surface, and if the light receiving range of 9" is larger, a signal is sent to lower the sample surface. Outputs
The control device receives the above signal and controls the X, Y, and Z of the sample stage.
By controlling the movement of the direction movement device 4 in the Z-axis direction, the image sensor 9
．． 9" is always the same width. In this way, even if the sample surface is somewhat uneven, the electron beam irradiation point on the sample surface is at the correct height during mapping operation. It has become.

When performing a mapping operation in the above configuration, the @control device 12 controls the height position of the sample using the signal from the focus detection device 11, and sets a preset limit amount for the amount of movement in the direction of raising the sample. If the in-focus state is still not obtained even after the amount exceeds the limit, it is determined that the sample surface has deviated from the optical axis of the electron optical system. The control bag fli12 controls the entire mapping operation, and controls the movement of the moving device 4 in the X and Y directions, takes in the output of the X-ray detector 6,
It also controls data processing, display, etc. for the captured X-ray detection data.

Scanning of the sample surface in the mapping operation is performed as shown in FIG. During scanning, the sample is fed in steps of one pixel in the positive direction of the X-axis, and when scanning along the X-direction scanning line of the book is completed, it is fed in steps of one pixel in the Y-direction, and then scanned in the negative direction of the X-axis. If the starting point of the next scanning line is violated, the step feed is performed one pixel at a time in the X-axis pressure direction again.

Conventionally, for irregularly shaped samples as shown in the second example (Xa, Y
a) (Xb, Ya) (Xa, Yb) + (Xb, Yb
), whereas the scanning range is changed to start from point A (Xa, Ya), scan to point 21, then return to R2 and scan to point 22. The mapping operation ends when reaching point B, which is determined according to the shape of the sample.

FIG. 3 shows an example of a flowchart of the operation of the control device 12 that performs the mapping operation described above.

When mapping, insert the sample into the EPMA, replace the image pickup elements 9 and 9' of the optical microscope with the eyepieces, shift the position of the light source backwards so that the entire surface of the sample is illuminated, and place the sample in the EPMA. Focus the optical microscope visually by moving it up and down. In this way, the sample surface is set at the normal height. Next, move the sample in X and Y directions and visually check the mapping viewpoint.

The end point position is determined, and the X and Y coordinates of the sample stage 3 when each position is brought to the center of the field of view of the optical microscope are read into the control device e12. The mapping viewpoint end points set in this way are indicated by A and B in FIG. 2, for example.

Thereafter, the eyepiece lens is replaced with an image pickup device 9,9゛. The horizontal coordinate values of points A and B are the coordinates of the sample stage 3, which is calculated by the controller fi12 counting the drive pulses supplied to the Y-axis and Y-axis drive motors of the moving device 4, which are driven by stepping motors. It is detected by Mapping is started by positioning the sample stage 3 at the starting point of mapping. In the mapping operation, the sample stage 3 is driven step by pixel in the X and Y directions. First, the optical microscope is driven one step in the positive X direction (a), and it is determined whether the optical microscope is in focus (b). This judgment is made by raising or lowering the sample surface from the focus detection bag fill.If neither signal is output, the focus is on; if it is, the moving device 4 is moved until the focus is reached according to the specified signal from the focus detection device 11. Drive the Z axis (c). When in focus, the X-ray detector output is taken into memory along with the sample stage coordinate data (2). When performing Z-axis drive due to in-focus, detect whether the amount of drive in the Z-axis direction exceeds the upper limit in step (e), and if it does not exceed the upper limit (No), proceed to step (b). Two-axis driving is performed until return to focus is achieved.If it is exceeded (YES), check whether or not focus was achieved at the previous sample stage position in step (v).If NO, the operation returns to (a). Initially, when starting from point A, point A is a point outside the sample, so the operation goes through a loop of (a), (b), (c), (e), (f), and (b), so that the sample moves along the X axis. The data is not captured during this time.When the sample surface comes under the electron beam irradiation point, the operation goes through a loop of (a), (b), (d), and (a). Data is acquired one pixel at a time along one scanning line in the X direction (as the scanning progresses along one scanning line and the electron beam irradiation point moves outside the right edge of the sample, The movement continues as (A), (B), (C), and (E) again.
Step becomes YES. In other words, the object that had been in focus until then could no longer be in focus because the sample surface had changed.
I know what happened. If the step (to) becomes YES, it is checked whether the Y-axis coordinate of the stage 4 is Yb (final scanning line), and if the result is No, the Y-axis coordinate of the moving bag e4 is checked.
Drive the axis one step (p), and step drive the Y-axis in the negative direction (p). In this step drive in the negative direction of the X-axis, the same operation steps (i) as in (a) to (f) above
Repeat steps to (to), and when step (to °) becomes YES, the operation returns to step (a) via (g'), (ch'). In this way, the zigzag scan of the sample surface progresses. However, when step (G) or (C) becomes YES, the mapping operation ends.

In the above example, the sample surface is scanned in a zigzag manner.
If you want to import analysis data only when moving in the X-axis pressure direction, and return quickly in the negative direction, the data acquisition step (2) will be skipped in the flow shown in Figure 3. , and the step of (chi) is (
Become.

According to the present invention, when mapping an irregularly shaped sample using EPMA or the like, it is not necessary to scan the area where there is no sample, so the time required for analysis is shortened.Moreover, since the scanning area is automatically determined according to the shape of the sample, the sample can be mapped in advance. There is no need for complicated operations such as setting the scanning area according to the shape of the image, and analysis efficiency is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram of a sample surface scanning trajectory according to the present invention, and FIG. 3 is a flowchart of the operation of a control device according to an embodiment of the present invention. be. DESCRIPTION OF SYMBOLS 1... Electron gun, 2... Electron objective lens, 3... Sample stage, 4... X, Y, Z 3-axis direction movement device, 5
...X-ray spectrometer crystal, 6...X-ray detector, 7...concave objective mirror, 8...mirror, 9,9°...imaging device, 10
... Semi-transparent mirror, 11... Focus detection device, 12...
Control device, S...sample, L...point light source. Agent Patent Attorney Hiroshi Agata IIw:A

Claims (1)

[Claims] A surface analysis device that scans the sample surface two-dimensionally, an optical microscope that has the same viewpoint as the above device on the sample surface, a focus detection device installed in the microscope, and a control that moves the sample three-dimensionally. This control device is designed to move the sample two-dimensionally within a predetermined vertical movement range of the sample surface and within the range where a focusing signal can be obtained from the focus detection device. Features surface analysis mapping device.