JPS63198250A - Surface analysis device - Google Patents

Abstract

PURPOSE:To obtain the desired measurement data by comparing the measured data with the preset reference value and setting the etching time in response to the condition change. CONSTITUTION:The measured value from a detector 4 is compared with the reference value preset from an input section 6 in sequence by a comparing means 7, and the resulting output is fed to a control means 8. Initial conditions such as the first and second etching time E1, E2 corresponding to the case of the rough analysis and the case of the fine analysis respectively and the total etching time are fed to the means 8 from the input section 6. The means 8 selects the time E1 when the measured value is ths reference value or less based on the output of the means 7 and selects the time E2 when the measured value exceeds the reference value to perform the control. The means 7, 8 are realized by a CPU and a memory. Accordingly, the desired measurement data can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a surface analysis device capable of performing analysis in the depth direction, such as ESCA or IMA.

(b) Prior art and its problems In this type of surface analysis device, for example ESCA, analysis in the depth direction is carried out by repeating pre-treatment such as etching and state changes, such as intensity measurements. It is done. In this kind of analysis, setting the etching time is important in order to analyze the necessary parts in detail.If the etching time is set too finely, the analysis will take time; No data will be obtained.

For this reason, conventionally, pre-measurements are carried out in advance, and conditions such as etching time are calculated and set based on the pre-measurements. Even with this setting, there are drawbacks such as the fact that predicted data may not be obtained due to differences in the performance of the etching apparatus.

The present invention has been made in view of the above-mentioned points, and aims to eliminate pre-measurement for setting conditions and troublesome setting of conditions, and to enable desired measurement data to be obtained. .

(C) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a method for analyzing the surface of a sample in the depth direction by alternately repeating pretreatment such as etching and measurement of state changes. In the analyzer, a comparison means for comparing a preset reference value of a state change with the measured value obtained by the measurement, and based on the output of the comparison means, the pretreatment time is controlled according to the state change. and control means for controlling.

(d) Effect According to the above configuration, the preprocessing time is controlled in accordance with the state change based on the measured value.

(e) Examples Examples of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of an embodiment of the present invention.

This embodiment will be explained by applying it to ESCA. In the figure, 1 is a sample, 2 is an etching means for performing ion etching as a pretreatment on the sample 1, 3 is an X-ray source that irradiates the sample 1 with X-rays, and 4 is an etching means for ion etching the sample 1 from the excited sample. A detector 5 for detecting photoelectrons is a drive mechanism for controlling these. This configuration is basically the same as the conventional one. This surface analyzer analyzes the sample I in the depth direction by alternately repeating etching and state change, in this example, measuring intensity.

In this embodiment, the reference value R set in advance from the input section 6 is
Comparing means 7 compares L with the measured value given from the detector 4, and control means 8 controls the etching time based on the output of the comparing means 7. Input section 6
The reference value RL that is set is a value that serves as a reference for a change in the state of the sample, and is set empirically. In this example,
The intensity of the specific element to be analyzed is selected to be sufficient to distinguish it from noise. Therefore, measured values that exceed this reference value RL are necessary data that does not contain noise, etc., and in areas where such measured values can be obtained, the etching time should be shortened and detailed measurements should be made. , conversely, the measured value below this reference value RL is
It is not very important as data, and it is desirable to increase the efficiency of analysis even if the etching time is increased.

The comparison means 7 successively compares this reference value RL with the measured value from the detector 4 and provides a corresponding output to the control means 8.

Initial conditions such as two types of first and second etching times El and E2 and a total etching time are inputted to the control means 8 from the input section 6. This first and second etching time E1. E2 corresponds to a case where a rough analysis is required and a case where a detailed analysis is required. Control means 8
Based on the output of the comparison means 7, the measured value is equal to the reference value RL.
If the measured value exceeds the reference value RL, the second etching time E2 is selected as it is necessary to perform detailed analysis. control.

The comparison means 7 and the control means 8 are realized by a CPU and memory.

Next, the operation of the surface analysis apparatus having the above configuration will be explained based on the flowchart of FIG. 2 and FIG. 3. Third
The figure shows the relationship between etching time and measured value (maximum intensity), where the horizontal axis shows the etching time and the vertical axis shows the maximum intensity.

First, in step nl, a reference value RL for state change is set, and the process moves to step n2. In step n2, the total etching time is set, and the process moves to step n3.
Now, there are two types of the first. Second etching time E1
, E2 are set and the process moves to step n4. step n4
Now, the first etching time El is initialized and the process moves to step n5. In step n5, the first etching time E
Etching is performed for 1 and then the process moves to step n6, where the intensity is measured. In step n7, it is determined whether the total etching time exceeds the set total etching time.

If it is determined in step n7 that the total etching time has not been exceeded, the process moves to step n8, and the measured value (
It is determined whether the maximum intensity) exceeds the reference value RL. When it is determined that the measured value does not exceed the reference value RL,
The process moves to step nlO, where the first etching time El is selected as there is no need for detailed analysis, and the process moves to step n5, where etching is performed at this first etching time El. In step n8, when it is determined that the measured value exceeds the reference value RL, the process moves to step n9, and the second etching time E2 is selected because detailed analysis is necessary, and the process moves to step n5. Etching is performed.

In step n7, when it is determined that the total etching time has been exceeded, the process moves to step nil, where a measurement end process is performed and the process ends.

In this way, since the etching is performed by selecting the etching time depending on whether the measured value exceeds the reference value RL, that is, depending on the state change, the reference value R is determined as shown in FIG.
For portions exceeding L, the etching time is shortened and detailed analysis can be performed, while for portions below the reference value RL, the etching time is lengthened for efficient analysis.

FIG. 4 is a schematic configuration diagram of another embodiment of the present invention.
Parts corresponding to the figures are given the same reference numerals. In this embodiment, the reference value RL, total etching time, first . Second etching time E
1 and E2 are set, and conditions for calculating the etching time are further set based on the rate of change (slope) of the measured value.

The control means 8a includes a slope calculation circuit 9 that calculates the rate of change of the measured value, that is, the slope in the characteristic diagram of FIG. An etching time calculation circuit 10 calculates an etching time E3 according to the slope based on the etching time E3, and either the calculated etching time E3 or the first etching time E1 set from the input section 6 is output from the comparing means 7. and a selection control circuit 11 that performs a selection based on the selection and predetermined control. The etching time calculation circuit IO calculates a shorter etching time based on the slope and the second etching time E2 as the slope becomes larger.Therefore, the larger the slope, the more detailed the analysis will be. .

FIG. 5 is a flowchart for explaining the operation of the embodiment shown in FIG. First, in step n1, a reference value RL is set, and the process moves to step n2. In step n2, conditions for calculating the etching time E3 according to the slope are set, and the process moves to step n3. In step n3, the total etching time is set, and the process moves to step n4. In step n4, two types of first etching time are set, as in the above embodiment. The second etching times El and E2 are set and the process moves to step n5. step n
In step 5, the first etching time El is initialized and the process moves to step n6. In step n6, etching is performed for the first etching time E1, and the process moves to step n7.
In step n7, the intensity is measured. step n8
Then, it is determined whether the total etching time exceeds the set total etching time.

If it is determined in step n8 that the total etching time has not been exceeded, the process moves to step n9, and the measured value (
It is determined whether the maximum intensity) exceeds the reference value RL. When it is determined that the measured value does not exceed the reference value RL,
The process moves to step n+2, where the first etching time E1 is selected as there is no need for detailed analysis, and the process moves to step n6, where etching is performed at this first etching time El. In step n9, when it is determined that the measured value exceeds the reference value RL, the process moves to step nlO, where the etching time calculated by multiplying the second etching time E2 by the coefficient value corresponding to the slope is determined as the need for detailed analysis. E3 is selected and the process moves to step n6, where the calculated etching time E3 is
Etching is performed.

In step n8, when it is determined that the total etching time has been exceeded, the process moves to step nil, where □ measurement end processing is performed and the process ends.

In this way, the etching time is selected depending on whether the measured value exceeds the reference value RL, and if the measured value exceeds the reference value RL, the etching is performed in consideration of the rate of change (slope). As shown in Figure 6, the reference value RL
For areas exceeding the standard value, the etching time is shortened according to the slope, allowing for more detailed analysis of the necessary areas than in the example shown in Figure 1.On the other hand, for areas below the standard value, the etching time is lengthened. This allows for efficient analysis.

In the above embodiment, only one reference value was set, but in another embodiment of the present invention, a plurality of reference values may be set, and the etching time may be controlled more finely depending on the range of the measured value. Of course, it may be configured to do so.

(f) Effects As described above, according to the present invention, the measured value is compared with a preset reference value and the etching time is set according to the change in state. It becomes possible to obtain desired measurement data without setting specific conditions.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
3 is a characteristic diagram showing the relationship between etching time and maximum strength obtained in the embodiment of FIG. 1, and FIG. 4 is a schematic diagram of another embodiment of the present invention. 5 is a flowchart for explaining the operation of the embodiment shown in FIG. 4, and FIG. 6 is a characteristic diagram showing the relationship between etching time and maximum intensity obtained by the embodiment shown in FIG. DESCRIPTION OF SYMBOLS 1... Sample, 2... Etching means, 3... X-ray source, 4... Detector, 7... Comparison means, 8, 8a...
- Control means.

Claims (1)

[Claims] (1) In a surface analysis device that performs depthwise analysis of a sample by alternately repeating pretreatment such as etching and measurement of state change, a preset reference value for state change and the measurement obtained by the above measurement are used. 1. A surface analysis apparatus comprising: a comparison means for comparing the values with the values; and a control means for controlling the pretreatment time according to a state change based on the output of the comparison means.