JPS5978437A - Charged particle beam irradiation type line analyzer - Google Patents

Abstract

PURPOSE:To realize line analizing along a desired long line by alternately operating a scanning means by beam deflection and a means for fine drive of sample and thereby supporting the scanning on the occasion of analyzing a line with an analyzer. CONSTITUTION:An analyzer such as X-ray microanalyzer is formed with an X- direction sample fine adjusting board X and a vertical direction sample fine adjusting board Z driven by a pulse motor MP. A height of a fine adjusting board Z is detected by a detector H and the data is then sent to a control circuit C in order to control the beam deflection through a scanning signal output circuit D. Simultaneously a number of pulses for moving the fine adjusting board X is calculated and it is set to a register R. Moreover, a pulse motor PM is driven by controlling the gate G. Accordingly, scanning for a long line can be realized in combination with beam deflection and movement of the fine adjusting board X and simultaneously only a pair of pulse motor PM is used in view of simplifying the structure.

Description

Detailed Description of the Invention The present invention provides a method for irradiating a sample with a beam of charged particles such as electron ions.
2. Detection of electrons, X-rays, etc. emitted from a sample 1--Relates to a ray analysis device in an analysis device such as an X-ray microanalyzer, which analyzes the sample.

When performing line analysis, that is, analyzing a sample along a single line, using the above-mentioned analyzer, there are two methods: deflecting a charged particle beam and scanning it electro-optically, and keeping the beam fixed while moving the sample. There is a way to do this.

In the method of deflecting the beam, the distance that can be scanned on the sample surface is less than 200 μm, and as soon as the analysis
When the distance exceeds μm, a method is used in which the sample is moved.

Conventionally, in order to move a sample for line analysis, a motor was attached to the sample fine movement device and the sample was driven by the motor, but with this method it was necessary to remove the motor if the sample was to be sent at high speed. . To explain in more detail, a high-speed feed motor was connected to the sample fine movement device, and several low-speed feed motors were connected via a clutch.

The motor used is a pulse smoke motor for both high-speed and low-speed feed. In the case of high-speed feed, the feed amount is about 0.5 μm per step of the motor, but in the case of low-speed feed, it is difficult to obtain the positional resolution of the analysis. The feed amount is about 0.01 μm per feed, and a reduction mechanism with a larger ratio than that for high-speed feed is interposed between the fine movement device and the motor. If the fine movement mechanism and the low-speed feed motor are still connected, the high-speed feed motor will have to carry around the low-speed feed motor at an increased speed, so the low-speed feed motor will have a large load. The motor is connected to a fine movement device via a clutch, and it is necessary to disengage the clutch when performing high-speed feed. In this way, conventionally, when performing line analysis over a length of 200 μm or more, the sample was moved using a low-speed feed motor, and when returning the fine movement device to its original position, the sample was switched to a high-speed feed motor. Therefore, in conventional charged particle beam irradiation analyzers such as X-ray microanalyzers, the sample fine movement device only requires two motors, one for high-speed feeding and one for low-speed feeding, a deceleration mechanism, and a motor for high-speed feeding. This is what we are trying to do.

The present invention is characterized by a charged particle beam irradiation method that alternately combines beam deflection and high-speed sample feeding to perform line analysis along an arbitrarily long line using a high-speed feeding motor. This relates to a mold analysis device. The present invention will be explained below with reference to Examples.

Figure 1 shows the sample surface. The sample is, for example, a copper material C'u mixed with iron impurity Fe, and a line analysis is performed along a single line X. The analysis range is from point A to point D on the X-ray. In the present invention, in this AD line analysis range, the charged particle beam is scanned by deflecting it to the left from point A to point B, and at the end of this scanning, the sample is sent to the right by a high-speed feed motor. , move point B to the position of point A in the figure. Thereafter, the beam is deflected once from right to left in the same range [ ] to scan the surface of the sample, thereby analyzing the BC value spread on the sample. Thereafter, similar operations are repeated to complete the line analysis over the entire length of AD. When the chart of the recorder is driven intermittently in conjunction with two continuous line analysis operations, the line analysis results for the X-rays from point A to point D on the sample will be displayed continuously as shown in Figure 2. / Obtained as a record. FIG. 3 is a time chart of the above-mentioned line analysis operation, and A in the figure is the X-direction scanning signal of the charged particle beam. It corresponds to points A and D. The beam is deflected from point A to point B in Figure 1 using the sawtooth waveform scanning signal in Figure 3, returns to point A, and then the sample is driven to bring point B to the position of point A on the sample. .

Figure 3 shows starting and stopping of the pulse motor.

The pulse motor is started by detecting the fall of the scanning signal and using this detection signal, and stops when a certain number of pulses have been supplied. The time interval from the end point of one sawtooth wave in the scanning signal to the start point of the next sawtooth wave is set to be longer than the period during which the pulse motor is rotating. The pulse motor moves the sample fine movement device by a distance equal to one scanning width of the beam by being supplied with the above-mentioned fixed number of pulses. FIG. 3C shows the chart feeding of the recorder, and the chart feeding is interrupted during the beam scanning period.

FIG. 4 shows the configuration of the device of the present invention. Bke electron beam, S
C is a beam deflection coil, L is an objective lens, and S is a sample. X: An X-direction sample fine movement table driven by a pulse motor PM. Reference numeral 2 denotes a vertical sample fine movement table, and the X-direction scanning width for the same beam deflection angle changes depending on the vertical position of the sample. H is means for detecting the height position of the sample fine movement table.

In the case of line analysis, as mentioned above, it is necessary to move the fine movement table in the X direction by a distance equal to the scanning width by beam deflection, so the height of the fine movement table Z in the Z direction is detected and the data is sent to the control circuit C. , the control circuit C calculates the number of pulses to be supplied to the pulse motor to move the fine movement table in the X direction by that width from the beam scanning width at that height, and sets the number in the register R. The control circuit C controls the scanning signal output circuit to control beam deflection, and also opens the gate G at the falling edge of the scanning signal. Gate) G is interposed between the pulse motor PM and the pulse generation circuit PG, and when this gate opens, the pulse motor PM starts.
The X-direction sample fine movement table X is driven. The pulses supplied to the pulse motor PM are counted by a counter, and the counted output is compared with the data set in the register R by the comparator Com. When the two match, the gate G is closed by the signal output from R. When the pulse motor PM stops, the counter K is reset.

According to the present invention, there is no need to use two pulse motors for driving the X-direction sample fine movement table, one for high-speed feeding and one for low-speed feeding, for line analysis, and the motor attachment/detachment mechanism, etc. that was necessary when using two motors, etc. Since line analysis is performed by adding scanning by beam deflection, the scanning speed can be freely set and a wide range of scanning speeds can be selected.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an example of a sample surface, Fig. 2 is a plan view of a record chart for line analysis, Fig. 3 is a time chart showing the operation of the embodiment device of the present invention, and Fig. 4 is a plan view of the present invention. 1 is a block diagram showing the configuration of a device according to an embodiment; FIG. B...Electron beam, SC...Beam supine coil, S
・・Sample, ,
G...Gate, K...Counter, R...Register, Com...Comparator. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] In an analyzer that detects radiation emitted from a sample by irradiating the sample with a charged particle beam, there is a means for scanning the sample surface by deflecting the charged particle beam, and a means for scanning the sample surface using the charged particle beam. A drive means for driving by the scanning width in this scan is provided in the opposite direction to the scanning direction, and the scanning means by beam deflection and the sample fine movement device drive means are operated alternately, and the recorder is moved by the beam irradiation type beam. Analysis equipment.