JP3021933B2 - X-ray data measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a characteristic X-ray generated from a sample by irradiating the sample with an electron beam and driving a sample stage in an arbitrary direction to scan the electron beam from a starting point to an ending point on the sample. The present invention relates to an X-ray data measurement device that collects data and performs line analysis.

[0002]

2. Description of the Related Art In an electron probe microanalyzer (EPMA), a sample is irradiated with an electron beam and characteristic X-rays generated from the sample are detected to analyze constituent elements of a substance. There are surface analysis for scanning a line two-dimensionally and line analysis for scanning a line linearly. Of which
In a line analysis by EPMA or the like in which a start point and an end point on a sample are set and an electron beam is linearly scanned from a start point to an end point, only the x-axis or the y-axis of the sample stage is driven and Was measured and the change in the X-ray intensity was recorded.

[0003]

However, there has been no device that smoothly drives a sample stage in an arbitrary direction to perform continuous line analysis. That is, in rare cases, a line analysis in an arbitrary direction at an arbitrary angle to the x-axis or the y-axis can be performed, but the stage drive is not usually smoothly and continuously driven at a constant speed. When driving the stage, even if there is one that can perform line analysis of a type that continuously drives smoothly, the target X-ray measurement position is removed because the X-ray measurement system and the stage drive system are not linked and controlled. There is a problem that X-ray data is collected. In addition, there is a type in which the stage drive is not continuous and the X-ray is measured while the stage is stopped after moving the stage by one step. In this case, the stage moves or stops, Vibration and driving noise,
In addition, the time during which no X-rays are measured occupies a large proportion of the entire data collection time, and therefore takes longer than necessary.

An object of the present invention is to provide an X-ray data measuring apparatus capable of continuously and smoothly driving a stage in an arbitrary direction to perform a line analysis. Is what you do.

[0005]

For this purpose, the present invention irradiates the sample with an electron beam and drives the sample stage in an arbitrary direction to linearly scan the electron beam from the start point to the end point on the sample. In an X-ray data measuring device for collecting data of characteristic X-rays generated from a sample and performing line analysis, an X-ray detecting means for detecting characteristic X-rays generated from a sample, and turning on an X-ray measurement gate at regular intervals X from X-ray detector
X-ray measurement means for taking in line data, a plurality of drive means for driving the sample stage in each drive axis direction, and a drive amount of each of a plurality of drive means calculated and driven from a designated start point and end point on the sample Data processing control means for controlling a plurality of driving means and X-ray measuring means to obtain a large amount of driving axes and measuring and processing the measured X-ray data, and driving the driving axis having a large driving amount by the X-ray measuring means The on-interval of the X-ray measurement gate is controlled based on a driving signal of the means.

[0006]

In the X-ray data measuring apparatus according to the present invention, the driving amounts of the plurality of driving units are set from the start point and the end point on the sample specified by the data processing control unit, and the driving axis having the large driving amount is set to the X-axis. Instruct the line measuring means, drive the sample stage in each drive axis direction by a plurality of driving means, and turn on the X-ray measuring gate based on the driving signal of the driving means of the driving axis having a large driving amount by the X-ray measuring means. Since the interval is controlled, the time for turning on the X-ray measurement gate can be finely controlled. In addition, the line analysis can be continuously performed without stopping the sample stage, and the vibration and noise of the stage driven by the motor can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an embodiment of an X-ray data measuring apparatus according to the present invention, wherein 1 is an electron gun, 2 is an electron beam, 3 and 4 are electron lenses, 5 is a sample, 6 is a stage, and 7 is a characteristic X. Line, 8
Is a spectral crystal, 9 is a spectroscope drive motor, 10 is an X-ray detector, 11 is an X-ray measurement device, 12 is a spectroscope drive control device,
13 is a storage device, 14 is a computer, 15 is a display output device, 16 to 18 are pulse motors, and 19 to 21 are drive control devices.

In FIG. 1, an electron beam 2 emitted from an electron gun 1 is squeezed finely by electron lenses 3 and 4 to irradiate a sample 5, and characteristic X-rays 7 generated from the sample are separated by a spectral crystal 8 to obtain X-rays. It is detected by the line detector 10. Then, the X-ray measurement data is taken into the computer 14 from the X-ray detector 10 via the X-ray measurement device 11 and analyzed, and the measurement data and the analysis result are stored in the storage device 13 and displayed as necessary. It is displayed on the output device 15. In addition, the computer 14
When an analysis condition is input by the analyst, the spectroscope drive control device 12, the X-ray measurement device 11, the drive control devices 19 to 2
Set control / measurement information to 1.

The pulse motors 16, 17, 18 drive the sample stage 6 in the x, y, and z-axis directions, respectively, and drive control devices 19, 20, 21 operate based on settings from the computer 14. The pulse motors 16, 17, and 18 are driven by generating drive pulses so that the irradiation position of the electron beam at the point moves from the given start point to the end point, and furthermore, at each specified step (a fixed number of drive pulses). In each case, a drive end pulse is generated and sent to the X-ray measurement device 11. The X-ray measurement apparatus 11 receives a signal of a drive axis (scan axis) having the largest drive amount from the computer 14, and the pulse motors 16, 17, and 18 drive the sample stage 6 by driving the drive controllers 19, 20, and 21. When moving from the start point to the end point, the drive end pulse of the drive axis having the largest drive amount is selected, the X-ray measurement gate is turned on and off, and the X-ray detector 10 measures X-rays.
X-ray measurement is performed by taking line data into a memory. The computer 14 controls each unit according to measurement conditions designated and input by a measurer using a keyboard, a mouse, or the like (not shown), and performs data processing control for measuring and processing X-ray data measured by the X-ray measurement apparatus 11. When the start point and the end point are specified as described above in the line measurement according to the present invention, the drive amounts in the x, y, and z-axis directions are calculated based on the specification, and the drive control devices 19, 20, 21
And a control means for setting control data in the X-ray measuring device 11 and measuring and processing the X-ray data measured by the X-ray measuring device 11.

FIG. 2 is a diagram for explaining an outline of processing by a computer, FIG. 3 is a diagram for explaining a relationship between a starting point, an ending point, and a drive shaft, and FIG. 4 is a diagram showing a measuring operation of the X-ray measuring apparatus. FIG. 5 is a diagram for explaining timing, and FIG. 5 is a diagram showing a configuration example of a control circuit of the X-ray measurement device.

When a start point and an end point are designated and input at the time of line measurement as shown in FIG. 2, the computer 14 inputs its coordinate values (x, y, z) (step S1),
Calculate the driving amounts in the y and z axis directions (step S
2). Subsequently, a drive axis having the largest drive amount is determined as a scan axis from among them (step S3).

Assuming that the specified start point S and end point E are on a plane composed of the x-axis and the y-axis as shown in FIG. From the angle θ between l and the x-axis, the x-axis direction is
The cos θ and y-axis directions are obtained by calculating l sin θ.
Therefore, when lcos θ is driven in the x-axis direction,
By driving sin θ in the y-axis direction, the irradiation position of the electron beam moves linearly from the start point S to the end point E. In the case of FIG. 3, since the x-axis direction is longer than the y-axis direction, the x-axis becomes the scan axis.

If the angle is 45 °, the drive amounts are the same, and there are a plurality of drive axes with the largest drive amounts. Therefore, it is checked whether or not one scan axis with the longest drive amount is present (step S).
4) In the case of two or more, for example, one scan axis is determined according to the priority order of x, y, z (step S).
5). Then, the drive amount (drive speed) and the number of pulses n for generating the drive end pulse are set as control data in each of the drive controllers 19, 20, and 21 (step S6), and the X-ray measurement device 11 uses the scan axis as control data. (Step S7).

As described above, each drive control device 19, 2
After setting the control data in 0, 21 and the X-ray measurement device 11, by starting, each drive control device 19,
20 and 21 drive the pulse motors 16 to 18 in accordance with the set drive amount and set the drive end pulse to X every n pulses.
X-ray measurement device 11
As shown in (1), every time the drive end pulse of the drive axis having the largest drive amount is input, the X-ray measurement gate is turned on / off to take the measured X-ray data into the memory. The sample stage 6
Is accelerated and decelerated in the region near the start point and the end point, and in this region, the interval between the drive end pulses is longer than that in the region where the constant speed is reached.

The control circuit of the X-ray measuring device 11 is, for example, as shown in FIG. 5, a driving end pulse selecting section including a selective driving axis register 31, AND gate circuits 32-1 to 32-3, and an OR gate circuit 33. The measurement control unit 34 detects a drive end pulse from a drive axis (scan axis) having a large drive amount.
Is configured to be input to Then, the measurement control unit 34
After the stage drive is started according to the time chart shown in FIG. 4, the X-ray measurement gate 35 is turned on / off and the measured X-ray data is taken into the memory every time a drive end pulse is input in n steps of the scan axis. The line measurement gate 35 and the measurement X-ray data acquisition unit 36 are controlled.

In this manner, the computer 14 determines the x-, y-, and z-axis drive speeds (pulse generation time intervals) and any of the pulse intervals n, x, y, and z-axes for transmitting signals to the X-ray measurement device 11. The selection is set, the measurement data of the X-ray measured by the X-ray measurement device 11 is fetched, the fetched measurement data is stored in the storage device 13, and the values are displayed in, for example, a graph. 15 is displayed.

Now, the number of data points to be collected by one line analysis scan is N, the X-ray collection time (dwell time) for each data point is T seconds, and the stage moves while collecting the data of this one point. The pulse step of the motor of the scan axis 6 is n. In this case, if the driving speed v of the stage 6 is equal to or less than n / T, data acquisition (X-ray measurement) of one point is completed during the movement of the stage, and a dummy time t during which the stage moves without data collection occurs. Will be. The dummy time t includes a time m for taking the measured X-ray data into the memory, a time g required for turning on the X-ray gate, and a time u from when the X-ray gate is turned off to when the stage has an n-step drive end pulse. Can be made shorter. For this reason, in FIG. 2, the dummy time is set to be large for easy understanding. However, the dummy time t can be suppressed to a value that can be practically ignored as compared with the X-ray measurement time. This makes it possible to reduce the total data collection time as compared with the case where the stage moves n steps and stops and then measures X-rays. In addition, if the dummy time occupying the entire data collection time becomes smaller, the time during which the X-ray is not measured during the driving of the stage becomes shorter, and the probability of missing the peak of the X-ray peak profile during this time becomes smaller. More accurate line analysis spectrum data collection becomes possible.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above-described embodiment, a pulse motor is used as the stage driving means. However, a micro step motor that drives in extremely small steps may be used, or a DC motor that does not rely on a pulse current may be used. However, when a DC motor is used, it is needless to say that position detection can be performed by means such as an encoder in order to provide a signal for starting X-ray measurement at a constant drive interval.

Although the scan axis is selected by the X-ray measuring device, a drive control device for outputting a drive end pulse from the computer is designated, and only the designated drive control device outputs the drive end pulse. You may. In this case, the register and the AND gate circuit are omitted in FIG. 5, and the line of the drive end pulse from each drive control device is directly connected to the OR gate circuit. Further, the number n of steps for generating the drive end pulse is set irrespective of the angle θ, but may be adjusted so as to be a predetermined unit length by a space length connecting the start point and the end point. That is, in FIG. 2, even if the scan axis is the same as the x axis with respect to the scan length l, when θ increases, n decreases, and conversely, θ
Is larger, n is increased to keep the distance of the stage 6 moving while collecting one point of data constant.

[0020]

As is apparent from the above description, according to the present invention, a plurality of driving amounts in the respective driving axis directions are set from a designated starting point and an ending point on a sample, and the driving amount is large. Since the axis is designated as the scan axis and the ON interval of the X-ray measurement gate is controlled based on the drive signal of the scan axis, the time for turning on the X-ray measurement gate can be finely controlled. In addition, continuous line analysis can be performed without stopping the sample stage, and the time for collecting data with the same dwell time per point can be reduced. Also, vibration and noise of the stage driven by the motor can be reduced. In addition, since the time during which the X-ray measurement gate is closed and driven can be minimized, a minute change in X-ray intensity in the line analysis path is correctly reflected in the collected data.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of an X-ray data measurement device of the present invention.

FIG. 2 is a diagram for explaining an outline of processing by a computer.

FIG. 3 is a diagram for explaining a relationship between a start point, an end point, and a drive shaft.

FIG. 4 is a diagram for explaining a timing of a measurement operation of the X-ray measurement device.

FIG. 5 is a diagram illustrating a configuration example of a control circuit of the X-ray measurement device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron gun, 2 ... Electron beam, 3 and 4 ... Electron lens, 5 ... Sample, 6 ... Stage, 7 ... Characteristic X-ray, 8 ... Spectral crystal, 9 ...
Spectroscope drive motor, 10: X-ray detector, 11: X-ray measurement device, 12: Spectroscope drive control device, 13: Storage device, 1
4 Computer, 15 Display output device, 16-18 ...
Pulse motor, 19-21 ... Drive control device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-78437 (JP, A) JP-A-1-144552 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 37/00-37/36 G01N 23/225

Claims (1)

(57) [Claims] 1. A sample is irradiated with an electron beam and a sample stage is driven in an arbitrary direction to linearly scan the electron beam from a start point to an end point on the sample to collect characteristic X-ray data generated from the sample. X-ray data measurement device for performing X-ray analysis by performing X-ray detection means for detecting characteristic X-rays generated from a sample, turning on an X-ray measurement gate at regular intervals,
X-ray measuring means for taking in X-ray data from the line detecting means, a plurality of driving means for driving the sample stage in each drive axis direction,
And calculating the driving amount of each of the plurality of driving means from the designated start point and end point on the sample, obtaining a driving axis having a large driving amount, controlling the plurality of driving means and the X-ray measuring means, and measuring the measured X. Data processing control means for measuring and processing the line data, wherein the X-ray measurement means controls the ON interval of the X-ray measurement gate based on the drive signal of the drive means of the drive shaft having a large drive amount. X-ray data measuring device.