JPH0442777B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for displaying the magnification of a sample image on the display screen of a scanning electron microscope or other electron beam apparatus (hereinafter referred to as SEM), and embodiments of this method. The present invention relates to a magnification display device for.

[Technical background] SEM irradiates and scans a sample with an electron beam, and displays an enlarged image of the sample on a display device (eg, CRT) based on sample signals generated during irradiation. Therefore, in the SEM, it is necessary to know how long an enlarged sample image corresponds to on the actual sample. For this reason, various methods have been proposed for SEM to display the scale of the sample together with the sample image on the display device.

[Prior Art] Conventionally, in a SEM, there are technical means for displaying the length on a sample according to the magnification together with the sample image, as shown in FIGS. 7 and 8, for example.

In the method shown in Fig. 7, scale 1 corresponding to a certain length (for example, 1 μm) on the sample is displayed together with sample image 2, and scale 1 is displayed on the display device according to the magnification of sample image 2. It is designed to expand and contract on the display screen 10 (Japanese Patent Publication No. 47-21345).

However, according to such means, the sample image 2
The length of scale 1 increases as the magnification of
There is a problem in that the length of the sample becomes small and the size of the sample cannot be determined accurately.

FIG. 8 shows a means for solving this problem. This displays on the display screen 10 a scale 4 having a constant length that is unrelated to the magnification of the sample image, and also displays the converted length of this scale 4 on the sample in characters ( Special Publication No. 58-51664). According to such means, problems such as the scale 4 protruding from the screen 10 of the display device or the scale 4 being too small and lacking in visibility can be solved.

[Problems with the prior art] However, in the case of such a method, when trying to find out the sample image length that is shorter than the set length of the scale 4, first, the length on the sample image 2 to be determined is shorter than the set length of the scale 4. The length on the sample image 2 must be determined by determining what fraction of the length corresponds to. However, using the length of the scale 4 as a standard, it takes time and effort to measure what fraction of that the length on the sample image 2 corresponds to, and it is not always possible to obtain an accurate value by measuring by eye. There is a problem.

In addition, the conventional display method described above has the problem that it is not always easy to accurately measure the length of the sample image in the vertical direction because no special consideration is given to measuring the length of the sample image in the vertical direction. be.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to easily and accurately determine the length in the vertical direction and the length in the lateral direction on the sample image. The purpose of the present invention is to provide a method and apparatus for displaying the magnification of a sample image, and the means for achieving this purpose is to display a reference line with a constant overall length on a display screen that displays a sample image, and to display a reference line with a constant overall length. In a sample image magnification display method in which the converted length on the sample image corresponding to is displayed as a character, a reference scale is displayed that divides the reference line according to the magnification, and one scale width of the reference scale is equivalent. The converted length on the sample image is displayed using characters, and the scale height of the reference scale is changed according to the magnification.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

1 to 3 illustrate a method for displaying the magnification of a sample image according to an embodiment of the present invention.

In this display method, as shown in FIG. 2, a reference line 2 is placed at the bottom of the display screen 10 that displays the sample image 15, and has a constant length regardless of changes in magnification.
In addition to displaying 0, the reference scale M that divides the reference line 20 is also displayed. This standard scale M
is a scale that is always displayed fixedly at the left end of the reference line 20.
M0, a scale M2 that is always displayed fixedly at the right end of the reference line 20, and a scale M1 that moves from left to right on the reference line 20 as the magnification increases. As shown in Figure 1, the scale M1 is 1x, 10x,
As the magnification increases by 10x, such as 100x and 1000x,
It is displayed at a position representing one-tenth of the length of the reference line 20. That is, if the length reference line between the scale M0 and the scale M2 is L, and the length between the scale M0 and M1 is the scale width l, then l=1/10L. When the magnification increases to 2x, l = 1/5L, and when the magnification increases to 10x, l = 1/10L again. Also,
The scale height h of the reference scale M is displayed to be 1/10 of the length scale width l between the scale M0 and the scale M1.
The length l and the scale height h of the scale M0 to scale M1 change proportionally depending on the magnification, and are always h=1/10l.

Further, on the right side of the reference line 20, at least the length L of the reference line and the converted length of the length scale width l of the scale M0 to scale M1 on the sample image 15 are displayed as characters. For example, if you also want to display the magnification, the magnification is 1.
If the reference line length is 100mm and the scale width l is 10mm, the display will be (×1, 100mm, 10mm).
When the magnification is doubled, the message (x2, 50mm, 10mm) is displayed. When the magnification is 10x, (×
10, 10mm, 1000μ). When the magnification is 10x, the scale height h is the sample image 15
Above, it is 1/10 of the scale width l, that is, the converted length is 100μ. By displaying in this manner, it becomes possible to perform measurements in both the vertical and horizontal directions more accurately than in the conventional measurement based only on the converted length of the reference line 20.

As a method of varying the height of the reference scale M, it goes without saying that the height between the scale M0 and the scale M1 may be displayed thickly, as shown in FIG.

Next, a magnification display device for implementing this method will be described. FIG. 4 shows a sample image magnification display device according to an embodiment of the present invention. This device consists of a horizontal deflection coil 40 and a vertical deflection coil 4 provided in an electron microscope main body (not shown).
By switching the current supplied to 1 using the magnification switching devices 42 and 43, the sample image 15 is enlarged and displayed on the CRT 45, and the reference line display means 50, the scale display means 60, and the character display means 70 are displayed. Necessary information regarding the length on the sample image 15 is displayed by each means.

In this figure, 51 is a horizontal scanning circuit that outputs a sawtooth signal Ex, and 53 is a reference voltage source that applies reference voltages E0 and E10 for positioning the start and end points of the reference line 20 to the comparison circuit 52. . This comparison circuit 52 allows the reference voltages E0 and E2 to match the sawtooth wave signal Ex, as shown in FIGS. 5a and 5b.
A signal is output at time points t1, t2,...t12. Also,
55 is a vertical scanning circuit that supplies a sawtooth wave signal Ey;
57 are reference voltages V1 and V2 for determining the thickness of the reference line 20 and the height position of the display on the display screen 10;
is the reference voltage for inputting to the comparison circuit 56.
The comparison circuit 56 outputs a pulse signal having a level between ta and tb when the reference voltages V1 and V2 match the sawtooth wave signal Ey, as shown in FIGS. 5c and 5d. The gate circuit 54 includes comparison circuits 52 and 56.
When the signals match, a signal as shown in FIG. 5e is outputted to the synthesizer 44. By this,
On the display screen 10 of the CRT 45, a reference line 20 of a certain length is displayed at an appropriate position. Reference numeral 61 denotes a scale reference voltage source that applies reference voltages E0 and E1 having different voltage values to the comparison circuit 62, respectively, corresponding to the reference scales M0 and M1. The sawtooth wave signal Ex from the horizontal scanning circuit 51 is input to the comparison circuit 62, and as shown in FIG. 6a and b, the reference voltages E0,
When E1 and the sawtooth wave signal Ex match, the pulse generation circuit 65 outputs signals on the reference scales M0 and M1. In addition, the reference voltage E2 corresponding to the reference scale M2
is input to the comparison circuit 62 from an independent reference voltage source 64 so as to be independent of the magnification. Therefore, the comparator circuit 62 outputs a signal on the reference scale M2 when the reference voltage E2 and the sawtooth wave signal Ex match, as shown in FIGS. 6c and 6d.

On the other hand, 67 is a reference voltage source that applies reference voltages V1 and V3 that determine the scale height of the reference scale M to the comparator circuit 66. A sawtooth wave signal Ey from the vertical scanning circuit 55 is input to the comparison circuit 66.
As shown in FIGS. 6e and 6f, when the sawtooth wave signal Ey and the reference voltages V1 and V3 match, a signal is generated between ta and tc. Therefore, the gate circuit 63 selects the sixth signal when the signals from the comparison circuits 62 and 66 match.
A signal as shown in Figure g is generated. Thereby, a reference scale M1 that moves from left to right on the reference line 20 according to the magnification and fixed reference scales M0 and M2 are displayed on the reference line 20.

Incidentally, since the scale reference voltage source 61 is set based on the reference voltage E0, the reference scale M displayed at the left end of the reference line 20 always remains at a fixed position. Furthermore, as shown in FIGS. 6c and 6d, since a constant value is always applied to the reference voltage E2 regardless of the magnification, the scale M2 is displayed fixedly at the right end of the reference line 20.

In addition, the voltage value of the reference voltage V3 is varied by switching the magnification such as 1x, 10x, and 100x, where one cycle is incrementing the number of rows by 10x, so the scale height is It repeatedly expands and contracts in response to changes in magnification every 10 times.

71 is a magnification display circuit, 72 is a reference line length display circuit, and 73 is a reference scale length display circuit. These circuits 71, 72, and 73 calculate numbers to be displayed as information using arithmetic devices such as microcomputers, and output the calculation results to the synthesizer 44 as information signals. Note that each display circuit 71, 72, 73 receives a sawtooth wave signal from the vertical scanning circuit 55 in order to determine the display position of the character.
Ey is taken and a character is displayed at a position that matches a preset reference voltage.

As described above, each signal inputted to the synthesizer 44 from the gate circuits 54, 63 and each display circuit 71, 72, 73 is transmitted to the CRT as a luminance modulation signal.
45, and displays the reference line 20, reference scale M, and characters on the display screen 10. It goes without saying that the horizontal deflection coil 40 of the SEM main body, the horizontal deflection coil 47 of the vertical deflection coil 41, and the vertical deflection coil 48 of the CRT 45 are synchronized by signals from the scanning circuits 51 and 55.

As explained above, with such a magnification display device, the magnification display method of the present invention as shown in FIGS. 1 to 3 can be implemented.

[Effects of the Invention] As explained above, the present invention displays a reference line of a certain length on the display screen of a CRT, and
While dividing the reference line and displaying a reference scale whose height varies depending on the magnification, the converted length on the sample image corresponding to the length of the reference line and reference scale width is displayed as a character. It is something. Therefore,
According to the present invention, it is possible to accurately measure the length of a sample image by using the lengths of the reference line and reference scale width and their converted lengths. Furthermore, since the height of the reference scale varies depending on the magnification, the length of the sample image, especially the length in the longitudinal direction, can be accurately measured.

[Brief explanation of drawings]

1 to 3 are diagrams showing a sample image magnification display method according to an embodiment of the present invention, FIG. 4 is a block diagram of a sample image magnification display device according to an embodiment of the present invention, and FIG. 6 is a time chart showing the operation of the sample image magnification display device according to the embodiment of the present invention, and FIGS. 7 and 8 are diagrams showing a conventional sample image magnification display method. 10...display screen, 15...sample image, 20...
Reference line, 50... Reference line display means, 60... Scale display means, 70... Character display means.

Claims (1)

[Claims] 1. A reference line with a constant overall length is displayed on the display screen that displays the sample image, and the magnification of the sample image is displayed based on the converted length character on the sample image to which the reference line corresponds. In the display method, a reference scale that divides the above-mentioned reference line according to the magnification is displayed, and the converted length on the sample image to which one division width of the reference scale corresponds is displayed as a character, and the scale of the above-mentioned reference scale is A method for displaying magnification of a sample image, characterized by changing the height according to the magnification. 2 a reference line display means for displaying a reference line with a constant overall length at a predetermined position on a display screen based on a horizontal sawtooth wave signal from a horizontal scanning circuit and a vertical sawtooth wave signal from a vertical scanning circuit; In the sample image magnification display device, the sample image magnification display device has a character display means for displaying a converted length on the sample image with a character, and a horizontal sawtooth wave signal from the horizontal scanning circuit and a horizontal sawtooth wave signal from the vertical scanning circuit. A scale whose voltage value changes in conjunction with the vertical sawtooth signal and the magnification switching device.The above reference line is divided according to the magnification based on the reference voltage, and a reference scale whose scale height changes according to the magnification is displayed. A reference scale display means is provided, and a converted length on the sample image corresponding to one scale width of the reference scale is calculated in conjunction with a magnification switching device.
A magnification display device for a sample image, characterized in that it is provided with a character display means for displaying the calculation result by a character.