JPH04341740A - Automatic inclination correcting device - Google Patents

Abstract

PURPOSE:To enable every operator to correct any inclination of a sample surface easily and in a short time by means of an automatic inclination correcting device. CONSTITUTION:The poisitoinal relation of a sample surface alpha to a specified plain-face is detected by using a parallel moving means 13 to move a sample 10 and then making surface detection by means of a surface detection means 11 at least at three points P1... not aligned in the same one line on the sample surface alpha. The paralell moving means 13 and an inclinating means 12 are driven in accordance with the detected results so that the sample surface alpha comes in a specific relation to the specified plain-face beta.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a sample moving and tilting device used in an electron beam microanalyzer, etc., and in particular, it corrects the tilt of the sample surface in order to make the sample surface coincide with a predetermined plane (measurement plane). Regarding equipment.

0002

2. Description of the Related Art In most electron beam microanalyzers, a spectroscopic optical system for dispersing X-rays is fixed, and accurate analysis cannot be performed unless the X-ray generation point is at a predetermined position. Therefore, even when performing surface analysis,
The electron beam irradiation point on the sample surface, which is the line generation point, must always be at a constant position, but the sample surface is tilted with respect to the moving plane of the sample moving table (this is the X-Y plane). When the sample is moved, the irradiation point shifts vertically. In order to correct the inclination of the sample surface with respect to the sample table moving plane, conventionally a mechanism for tilting the sample is provided between the sample table's X-Y plane moving device and the sample, and the sample surface is observed with an optical microscope. While moving the sample, the tilt of the sample was adjusted so that three points on the sample surface were in focus.

0003

SUMMARY OF THE INVENTION In the conventional tilt correction method described above, it is necessary to perform visual focusing at three points each time the sample is changed, which takes time and effort. Furthermore, if the surface of the sample has no features, it may be difficult to visually detect that the sample is in focus. The present invention was made to solve such problems, and its purpose is to easily enable anyone to
Moreover, it is an object of the present invention to provide an automatic tilt correction device that can correct the tilt of a sample surface in a short time.

0004

[Means for Solving the Problems] In an automatic tilt correction device according to the present invention, which has been made to solve the above problems, as conceptually shown in FIG. (b) surface detection means 11 for detecting whether or not the sample 10 is located at a predetermined point p0 within the predetermined plane β;
(c) a tilting means 12 that tilts the sample 10 with respect to the predetermined plane β; and (d) a parallel displacement means 13. the sample 10 is moved, and the surface detection means 11 detects the surface of the sample surface α at at least three points p1, . It is characterized by comprising a tilt correction control means 14 that drives the parallel movement means 13 and the tilt means 12 so that the sample surface α has a predetermined relationship with respect to the predetermined plane β based on the detection result.

[0005]

[Operation] The operation of the tilt correction control means 14 will be mainly explained. First, the surface detection means 11 detects the sample surface α at a predetermined point p.
0 (p0∈α). If the sample surface α is not at the predetermined point p0, the parallel moving means 13 moves the sample so that the sample surface α is at the predetermined point p0. When the sample surface α reaches a predetermined point p0 (this is referred to as "detection of the sample surface"), the position L1 of the sample at that time is memorized by the control parameters of the parallel movement means 13, etc. Next, the parallel moving means 13 is moved in a plane parallel to the predetermined plane β (referred to as the X-Y plane) to change the position of the sample 10. The sample surface α is similarly detected at this position of the sample 10, and the position L2 of the sample 10 at that time is stored. In this way, the sample surface α is detected at at least three points,
The positions L1, L2, and L3 of the sample 10 at each point are memorized. Here, these three points (points on the sample surface α that have reached the predetermined point p0) p1, p2, and p3 (p2 and p3 are not shown) are made not to lie on the same straight line. These three points p1, p2, p3
Since the plane defined by is nothing but the sample surface α,
From the positions L1, L2, and L3 of the sample 10 corresponding to each point,
The position of the sample surface α (in the reference coordinate system of the sample positions L1, L2, L3) is determined. On the other hand, since the position of the predetermined plane β with respect to the same reference coordinate system is known, the relationship of the sample surface α with respect to the predetermined plane β is detected thereby.

Based on the relationship between the sample surface α and the predetermined plane β thus detected, the sample is tilted by the tilting means 12, and the parallel moving means 13 (particularly in the direction perpendicular to the X-Y plane = (movement in the Z-axis direction) to place the sample surface α at a predetermined position with respect to a predetermined plane β (for example, by moving the sample surface α
can be made to coincide with the plane β, be inclined by a predetermined angle from the plane β, etc.).

[0007]

Embodiment FIG. 2 shows the structure of a sample moving and tilting device for an electron beam microanalyzer (EPMA) which is an embodiment of the present invention. The sample moving and tilting device of this embodiment uses an electronic imaging device 30 as a surface detection means, and its image sensor 3
1 is processed by the image signal processing device 20, the focus determination device 21 determines whether the focus of the optical system of the imaging device 30 is on the surface of the sample 34 in the sample chamber 33. judge. For focus determination processing by these devices, those used in ordinary video cameras and the like can be used.

[0008] Both the parallel moving means and the tilting means can be those provided in a conventional sample moving and tilting device. In this embodiment, the movement of the moving stage 38 in the XYZ axis directions (see the coordinate system at the bottom of FIG. 2 for each direction) is performed by the respective pulse motors 40, 41, and 42, and the inclination of the sample stage 35 with respect to the moving stage 38 is It is adjusted by two DC motors 36 and 37. Tilt motors 36, 37
are the inclination angle θx in the X-axis direction and θy in the Y-axis direction, respectively.
This is to adjust the Parallel movement pulse motor 40,
41, 42 and the tilting DC motors 36, 37 are driven by respective motor drivers 24, 23, and each motor driver 23, 24 is controlled by a microcomputer 22, which will be described later.

A microcomputer 22 is used as the tilt correction control means. The operation of the microcomputer 22 for correcting the inclination of the sample 34 in this embodiment will be explained with reference to the flowchart of FIG. First, it is detected based on a signal from the focus determination device 21 whether or not the focus of the optical system of the imaging device 30 is on the surface of the sample 34 (step S10). The focal position of the optical system of the imaging device 30 is adjusted to be at the same height as the focal position of the X-ray optical system of the EPMA of this embodiment. If it is determined in step S10 that the image is out of focus, the microcomputer 22 drives the Z-axis pulse motor 42 (step S11) to move the moving stage 38 up and down. When the optical system is focused at any point in time, the process proceeds to step S12, and the XYZ coordinate values (Fx1, Fy1, Fz1) of the moving stage 38 at that position are stored in the memory. Note that the number of pulses of the pulse motors 40, 41, and 42 can be used for this coordinate value.

In the next step S13, it is determined whether this focus detection has been performed three times. If the measurement has not been performed three times yet, first in step S14, the X-axis and Y-axis pulse motors 40 and 41 are driven to move to an XY coordinate point different from the XY coordinates of the previous measurement point. At this time, if focus detection has already been performed twice by then, the next
Make sure that the point does not lie on the straight line connecting the previous two points. When the movement of the XY coordinates is completed in step S14, the process returns to step S10, and the processes of steps S10 to S12 described above are repeated in the same way, and the XYZ coordinate values (Fx
2, Fy2, Fz2) in memory.

[0011] In this way, the focus is detected at three points, and the coordinate values of each point (Fx1, Fy1, Fz1), (Fx2, Fy2
, Fz2), and (Fx3, Fy3, Fz3) in the memory, the process proceeds to step S15 to calculate the equation of a plane passing through the three points. This plane is nothing but the surface α of the sample 34. Once the equation of the sample surface α is determined, the inclination angle θ of the sample surface α with respect to the moving plane (X-Y plane) of the moving stage 38 is determined.
x and θy are calculated (step S16).

After the equation of the sample surface α and the inclination angles θx and θy are determined, finally in step S17, each inclination motor 3
6 and 37 to make the sample surface α parallel to the X-Y plane, and drive the Z-axis motor 42 to adjust the sample surface α to a predetermined height (focal position of the optical system of the imaging device 30). . As a result, when performing two-dimensional X-ray analysis of the sample surface α, even if the sample is moved within the X-Y plane by the pulse motors 40 and 41, the sample surface α will always remain within the same plane. X-rays will always originate from a fixed point.

[0013] In addition to the above-mentioned imaging device, an ultrasonic range finder, a phase difference detection type focus detection device, etc. can also be used as the surface detection means.

[0014]

Effects of the Invention The automatic tilt correction device according to the present invention does not require focus determination by human eyes, so that tilt correction can be performed easily, quickly, and accurately. Also,
By using an ultrasonic ranging device etc. as a surface detection means,
It becomes possible to easily perform tilt correction even on a sample with no features on the surface (for example, a mirror-polished sample). This tilt correction device is suitable for normal
In addition to the line microanalyzer device, it can also be applied to devices that require the sample surface to be tilted by a predetermined angle (for example, a stereo scanning electron microscope that takes images twice by tilting the sample by about 5 degrees).

[Brief explanation of the drawing]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention.

FIG. 2 is a block diagram showing the configuration of an EPMA sample moving and tilting device that is an embodiment of the present invention.

FIG. 3 is a flowchart of sample tilt correction processing performed by the microcomputer, which is the central processing unit of the sample moving and tilting device of the embodiment.

[Explanation of symbols]

α…Surface of sample
β...Predetermined plane p0...Predetermined point on plane β
p1... Point 35 on the surface of the sample... Sample stage
36, 37...Tilt motor 38...Movement stage
40, 41, 42...X, Y, Z axis motor

Claims (1)

[Claims] 1. Surface detection means for detecting whether the sample surface is at a predetermined point within a predetermined plane; and parallel movement means for translating the sample in a plane parallel to the predetermined plane and in a direction perpendicular thereto. Then, the sample is moved using a tilting means for tilting the sample with respect to the predetermined plane and a parallel movement means, and the surface of the sample is detected by the surface detection means at at least three points on the sample surface that are not on the same straight line. The positional relationship of the surface with respect to a predetermined plane is detected, and based on the detection result, the sample surface has a predetermined relationship with respect to the predetermined plane.
An automatic tilt correction device comprising a parallel movement means and a tilt correction control means for driving a tilt means.