JPS61233949A - Method and device for indicating magnification of image of sample - Google Patents

Abstract

PURPOSE:To accurately measure the length of a sample regardless of the size of the image of the sample, by indicating a reference line of prescribed length on a display surface, and using characters to indicate the converted length of every graduation interval for the image of the sample. CONSTITUTION:The image 15 of a sample and a reference line 20 are indicated on a display surface 10. Information on the reference line 20 is indicated by characters 30 on the display surface 10. The length of the reference line 20 on the display surface 10 is always fixed despite the change in the magnification of the sample image 15. Reference graduation marks 25, which divide the reference line 20, and auxiliary graduation marks 26, which equally divide the interval between the reference graduation marks, are indicated for the reference line 20. The enlargement scale 31 of the sample image 15, the length 32 of the reference line 20, which is converted in terms of the actual length of the sample, and the length 33 between the reference graduation marks 26, which is converted in terms of the actual length of the sample, are indicated by characters 30 such as digits and unit-representing characters under the right-hand portion of the reference line 20. The length of the sample can be accurately found out through these indications.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for displaying a specimen image at a magnification of 1 in a scanning electron microscope or other electron beam equipment (hereinafter referred to as SEM), and a method for displaying a sample image at a magnification of 1 for carrying out this method. This invention relates to display devices.

[Technical Background] In the SEM, a sample is irradiated and scanned by an electron beam, and a sample magnifier displays a sample image on a display device (for example, a CRT) based on a sample signal generated during the 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 of displaying the scale of the sample along with the sample image on a display device have been proposed for SEM.

[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. 9 and 10, for example.

9th y! In the method of increasing scale 1 to 1, 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 according to the magnification of sample image 2.
is expanded and contracted on the display screen 101 of the display device (Japanese Patent Publication No. 47-21345).

However, according to such means, as the magnification of the sample image 2 increases, the quality of the scale 1 increases;
If the scale 1 protrudes from the screen 1o or if the magnification is low, the flow of the scale 1 becomes small, resulting in a problem that the size of the sample cannot be determined accurately.

FIG. 10 shows a means for solving this problem. This displays on the display screen 10 a scale 4 having a fixed length that is unrelated to the magnification of the sample image, and also displays the converted length of this scale 4 on the sample as a character 5. Yes (Tokuko Sho 58-5166
No. 4). According to such means, when the scale 4 protrudes from the screen 10 of the display device or when the scale 4 is too small and you want to know the sample image length that is shorter than the set length, first, the sample image to be obtained is The length on the sample image 2 must be determined by determining what fraction of the length of the scale 4 corresponds to the length on the sample image 2, and then multiplying by the factor ll1llII corresponding to the magnification factor.

However, it is time-consuming to measure the length of the sample image 2 based on the length of the scale 4, and it is not always possible to obtain an accurate value by eye. Can not. In addition, since the converted value according to the magnification ratio is generally not an integer value, it is necessary to perform calculations using converted values with fractions, but such calculations are cumbersome and! ! Easy to make 1v9 mistakes.

Also, if you try to convert the conversion value into an integer value that is easy to calculate, you will have to change the magnification ratio to make it a specific value.
This is inconvenient due to restrictions on the use of the device.

[Means for Solving the Problems] The present invention has been made to solve the problems of the conventional methods described above. The purpose of the present invention is to provide a magnification display method and a magnification display device that can easily and accurately determine the sample image. A reference scale that displays a line and forms a scale width that changes according to the magnification of the sample image on this reference line, and subdivides the scale width of the reference scale when one scale width of this reference scale is equal to or larger than a predetermined width. In addition to displaying the sub scale, the converted length of the reference line on the sample and the converted length of one scale width of the reference scale on the sample are displayed as characters. In addition, for devices that implement this display method, there is a standard in which the total length is fixed at a predetermined position of the display device based on the horizontal sawtooth wave signal from the horizontal scanning circuit and the vertical sawtooth wave signal from the vertical scanning circuit. a reference line display means for displaying a line; and a reference scale on the reference line and subscales for subdividing the reference scale based on a reference voltage whose value changes according to changes in voltage and magnification of the horizontal sawtooth wave signal. and a character means for displaying the total length of the reference line and the converted length of one division of the reference scale on the sample.

[Example 1 Hereinafter, the present invention will be described in detail based on the accompanying drawings.

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

In FIG. 1, reference numeral 10 is a display screen for displaying a sample image;
This display screen 10 includes a reference line 20 along with a sample image 15.
and information regarding the reference line is displayed by character-30.

The reference line 20 always has a constant length on the display screen 10 regardless of changes in magnification of the sample image 15. Then, on this reference line 20, a reference scale 25 that divides the reference 41120 and a subscale 26 that subdivides the space between the reference scale 25 into equal parts are displayed. JI! 1! The scale 25 is, for example, 1μ- on the sample image 15, with the left end of the reference line 20 being O.
It is displayed sequentially to the right as one scale. Furthermore, as shown in an enlarged view in FIG. 2, the subscale 26 subdivides the space between the reference scales 25 into equal parts (for example, 10 equal parts), but the display position of the subscale 26 is 25 no 0
and 1, or between 5 and 6, etc., and can be changed as appropriate. Note that the reference scale 25 and the subscale 26 are distinguished by, for example, displaying the reference scale 25 large and the subscale 26 small.

As shown in FIG.
, the reference line length 32 does not represent the length on the sample image 15 to which the quality of the reference line 20 corresponds, and the reference scale length represents the length on the sample image 15 to which the length of one graduation of the reference scale 26 corresponds. 33, and these are characters such as numbers and their units - 30
is displayed. Therefore, by these displays, sample image 1
You will be able to accurately know the merits of 5.

FIG. 3 shows various cases of such magnification display methods. That is, by enlarging the magnification of the sample image 15, the reference scale 25 and the subscale 26 are sequentially moved to the right, and the width of each scale is enlarged according to the magnification. Therefore, the reference scale 25 disappears one by one as it crosses the right end of the reference line 20. Also, at this time, a new standard scale 25
A new subscale 26 is displayed between (for example, 0 and 1). Further, the display of the character 30 is also sequentially changed in accordance with the enlargement of the magnification.

Conversely, when decreasing the magnification, the magnification display is opposite to that when the magnification is enlarged. That is, as shown in FIG. 3, when transitioning from a high magnification state to a low magnification state, a new reference scale 25 appears at the right end of the reference line 20, and when the magnification drops below a certain level, the previous reference scale 25 is changed to the subscale 26. Further, in accordance with the change in magnification, the numerical values of each display 31°32.33 by the character 30 are also changed.

Note that the reference scale 25 and the subscale 26 may be displayed as long as they can be visually distinguished, so they may not only be indicated by lines perpendicular to the reference line 20 as shown in FIGS. The display method may be, for example, a display method such as changing the color.

Next, an example of a magnification display device for carrying out the above display method will be described.

FIG. 4 shows a sample image magnification display device according to an embodiment of the present invention. This device uses magnification switching devices 42 and 43 to supply current to a horizontal deflection coil 40 and a vertical deflection coil 41 provided in an electron microscope main body (not shown).
By switching, the specimen image 15 is enlarged and displayed on the CRT 44, and the reference line display means 50
, the scale display means 60, and the character display means 70 display necessary information regarding the length on the sample image 15.

In this figure, 51 is a horizontal scanning circuit that outputs a sawtooth signal Ex to the horizontal deflection coil 40 and a comparison circuit 52, and 53 is a comparison circuit that compares reference voltages EO and E10 for positioning the start and end points of the reference line 20. This is a reference voltage source applied to 52. As shown in FIGS. 5a and 5b, this comparison circuit 52 operates at a time tl where the reference voltages EO, E10 and the sawtooth wave signal Ex match.

(2... At the time of tl2, a pulse signal is output to the gate circuit 54. Also, 55 is a vertical deflection coil 4
1 and a vertical scanning circuit that supplies a sawtooth signal Ey to the comparison circuit 56; 57 is a reference voltage Vl that determines the thickness of the reference line 20 and the height position of the display on the display screen 10;
It is a reference voltage source that inputs V2 to the comparator circuit 56. As shown in FIG.
-tb, the gate circuit 54 sends a pulse signal that becomes H level.
Output for. The gate circuit 54 opens its gate when the signals from the comparison circuits 53 and 56 match, and outputs a signal as shown in FIG. 5e to the synthesis circuit 44. As a result, a reference line 20 of a certain length is displayed on the display screen 10 of the CRT 45 at an appropriate position.

Reference numeral 61 denotes a scale reference voltage source that supplies the comparator circuit 62 with the same number of reference voltages EO to E9 having different voltage values as the number of reference scales 25 that divide the reference $120.

The sawtooth wave signal Ey from the horizontal scanning circuit 51 is input to the comparison circuit 62, and as shown in FIGS. 6a and 6b, when the reference voltage EO-E9 and the sawtooth signal Ex match, , and output pulse signals in units of 10 to the gate circuit 63. Further, the 1 & quasi voltage E10 for displaying the reference scale 25 displayed at the right end of the reference line 20 is supplied from an independent reference voltage source 64 to the comparison circuit 6 so as to be independent of the magnification.
2 is input. Therefore, the comparator circuit 62 is shown in FIG.
, d, the sawtooth wave signal Ey and the reference voltage E10
It also generates a pulse signal when the two match.

On the other hand, reference voltage V1.65 determines the scale height of the reference scale 25. This is a reference voltage source that applies V3 to the comparator circuit 66. The comparison circuit 66 receives the sawtooth signal EV from the vertical scanning circuit 55, and as shown in FIG. A pulse signal is generated at tc111. Therefore, the gate circuit 63 generates 11 pulse signals as shown in FIG. 6 when the signals from the comparison circuits 62 and 66 match. As a result, on the reference line 20,
A reference scale 25 that divides the reference 11120 into ten equal parts will be displayed. Note that the reference voltages E1 to E9 are magnification reference voltages lI4 whose voltage values change in conjunction with switching of the magnification.
Since the magnification of 6 moves a depending on the reference voltage, as shown in FIG. 7a, when the magnification becomes high, the reference voltage E1~
E9 also fluctuates and becomes higher in voltage value than the sawtooth signal El. Therefore, the number of pulse signals generated from the comparator circuit 62 decreases as the magnification increases, as shown in FIG. However, since the scale reference voltage source 61 is set based on the reference voltage EO, the reference voltage EO does not change even if the magnification is changed. Therefore, the reference scale 25 displayed at the left end of the reference line 20 always remains at a fixed position. Further, as shown in FIGS. 7c and 7d, since the base MP-voltage E10 is always applied as a constant value regardless of the magnification, the comparator circuit 62 always generates a pulse signal at a constant time. Therefore, the reference scale 25 continues to be displayed in a fixed manner at the right end of the reference 120. After all, when the magnification is decreased, the reference marks 25 are displayed fixedly at the right and left ends of the reference line 20, and the reference date a25 sequentially moves to the right and disappears depending on the magnification. Teyuku (
(See Figure 7e).

Reference numerals 67 indicate different reference voltages E00 and EOl, the same number as the number of subscales 26 dividing the reference scale 25 into equal parts.
,...E 09 (E 01 to EO9 are, for example, EO
This is a subscale reference voltage source that applies a voltage value between .about.E1) to the comparator circuit 68. The comparison circuit 68 receives the sawtooth wave signal Ex from the horizontal scanning circuit 51, and the comparison circuit 68 inputs the sawtooth wave signal EX and the reference voltages EOO to EO9.
When they match, Figure 8a.

As shown in b, a pulse signal is generated similarly to the comparison circuit 62. This signal is supplied to the grid of the CRT 45 as a luminance modulation signal via the gate circuit 63 and the synthesizer 44, and is displayed on the display screen 10 as 01st @26 which subdivides the reference date #t25. In addition, the reference voltage EOI
~EO9 changes depending on the switching of the magnification, but the reference voltage EOO remains constant compared to the scale reference voltage EO~
It is similar to E9. In addition, this reference voltage EOO~EO9
Depending on how the value is taken, the subscale 26 will be set to the reference date T112.
It becomes possible to display the screen so as to divide it equally between any number of 5.

71 is a magnification display circuit; 72 is a reference line length display circuit; 7
3 is a reference scale length display circuit. . ,,Circuit 7 of L et al.
1.72.73 uses an arithmetic device such as a microcomputer to calculate the number to be displayed as information, and outputs the calculation result to the synthesizer 44 as an information signal. In addition, each display circuit 71, 72, 73 is a character-3
In order to determine the display position of 0, the sawtooth wave signal Ey is taken from the vertical scanning circuit 55, and the character -30 is displayed at a position that matches a preset reference voltage.

As described above, each signal inputted to the synthesizer 44 from the gate circuit 54.63 and each display circuit 71, 72.73 is outputted to the grid electrode of the CRT 45 as a brightness modulation signal, and displayed on the display screen 10. Reference line 20, reference scale 2
5. A subscale 26 and a character 30 are displayed. It goes without saying that the horizontal deflection coil 4o and vertical deflection coil 41 of the SEM body and the horizontal deflection coil 44 and vertical deflection coil 48 of the CRT 45 are synchronized by signals from the scanning circuits 51 and 55.

The operation of this magnification display device will be explained using FIG. 3.

Now, if the magnification is 1x and the reference line length is set to 100III11 as shown in Figure 3a, the display screen 1
0, a reference line with a length of 100 mm is displayed by the reference line display means 50, and the display circuit 71.72 displays a sample image 1 with a magnification of x1 and a reference line length corresponding to that of the sample image 1.
The converted length 100■ on 5 is displayed in characters. Further, the scale display means 60 displays a reference scale 25 that divides the reference line 20 into ten equal parts. Also, reference scale 2
The converted length on the sample image 15 of one scale length of 5 is displayed as 1oIIIm by the reference scale length display circuit 73.

Further, a subscale 26 is also displayed, and one scale is 1.times., but instead, a character of n length is not displayed.

Next, as shown in FIG. 3, when the magnification is doubled, the magnification reference voltage is doubled. As a result, the applied voltage of the scale reference voltage source 61 is also doubled, and the interval between the reference scale 25 and the open eye #t26 is also displayed as being doubled. At this time,
The portion exceeding the reference voltage E10 of the reference voltage source 64 will not be displayed.

In the character display at this time, the magnification is ×2, the reference line length is 50IIll, and the reference scale length is 10■. Next, when the magnification is changed to 5 times as shown in FIG. 3C, the interval between the scale marks 25 and 26 increases by 5 times. At this time,
For character display, the magnification is ×5, the reference line length is 201,
The standard scale quality is 101111. Furthermore, if the magnification is increased to 10 times as shown in Figure 3d, ! 1 directrix 20 and eye t
A25 and 26 are displayed in the same way when the magnification is 1x.

However, in this case, the character display is magnification x 10
, the reference line length is displayed as 1010l11 and the reference scale is 1000μ, so you can know that the converted length has changed.

In this way, the character display changes by switching the magnification, but the length of the reference line remains the same, and the scale lines 25 and 26 are repeated as the same display every 10 times. Therefore, as the magnification increases like 10 times, 100 times, 1000 times, etc., the reference line length and reference scale length become 1/10.1/100.1/1.
000 and getting smaller. That is, each time the digit of the magnification changes, the number of digits such as the reference line length also changes.

Note that the reference line display means 5 of the magnification display device according to the above embodiment
0 and the scale display means 60 have been described as being processed in an analog manner, but the present invention is not limited to this, but may also be performed using other means for performing similar operations, such as digital processing using a microcomputer or the like. Of course, it may be configured.

As explained above, according to the magnification display method and device according to the embodiment of the present invention, the reference line 20j3 and the reference scale 2
5. The length on the sample image can be accurately known by the display of the sub scale 26 and the display of each character. In addition, even if the converted length of the reference line 20 etc. is not an integer depending on the magnification, the length on the sample image 15 can be easily calculated based on the respective numbers displayed as 625.26.・Measurements will be accurate. Furthermore, since the length of the reference line 20 is always constant, it does not protrude from the display screen 10 or become too small to be seen, allowing accurate measurement. Furthermore, since the conversion quality on the sample image 15 is displayed as a character, even if the display screen 10 is copied onto a photograph and enlarged, the length can be measured with the same dimensions.

[Effects of the Invention] As described above, the present invention provides a reference scale that displays a reference line of a certain length on a CRT display screen, divides the reference line, and divides one division of the reference scale into equal parts. In addition to displaying subscales that subdivide the reference scale into subdivisions, the reference line and the converted length of one scale of the reference scale on the sample image are displayed as characters. Therefore, according to the present invention, by using these magnification displays, the length on the sample image can be accurately measured regardless of the size of the sample image. In addition, even if the converted length of the reference line, etc. becomes a complicated number with a fraction due to switching the magnification, the converted length of the reference line and the converted length of the reference scale that divides it, and the reference scale can be further subdivided. Since the subscale is displayed, it becomes easy to calculate the converted length, eliminating calculation errors and ensuring the accuracy of measurement. Also, since calculation is easier,
This eliminates restrictions on the operation of the device, such as changing the magnification ratio to make the converted length an integer.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a magnification display method for a sample image according to an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1 showing magnification display on the display screen, and FIG. FIG. 4 is a block diagram showing the magnification display device according to the embodiment of the present invention, and FIGS. 5 to 8 are time diagrams showing the operation of the magnification display device according to the embodiment of the present invention. Chart, No. 9
This figure and FIG. 10 are diagrams showing a conventional magnification display method. 10...Display screen 20...Reference line 25...
・Reference scale 26...Subscale 30...Character 50...Reference line display means 60...Scale display means 70...Character display means! ! I 8 Figure 119 Illustration procedure amendment 1980 ¥: October 31

Claims (5)

[Claims] (1) A reference line with a constant overall length is displayed on the display screen that displays the sample image, and a reference scale that forms a scale width that changes depending on the magnification of the sample image on this reference line, and this reference scale. When one scale width is equal to or larger than a predetermined width, a subscale that subdivides the scale width of the reference scale is displayed, and the converted length of the reference line on the sample and the conversion length of the one scale width of the reference scale on the sample are displayed. A method for displaying magnification of a sample image, characterized by displaying the length as a character. (2) The sub scale becomes a reference scale when the width of one scale of the reference scale exceeds the length of the reference line due to magnification expansion. Magnification display method. (3) The sub scale has an interval of one scale width of the reference scale of 10
A method for displaying a magnification of a sample image according to claim 1, wherein the sample image is divided into equal parts. (4) The sample image magnification display method according to claim 1, wherein the reference scale and the subscale are displayed in a visually distinguishable manner. (5) reference line display means for displaying a reference line with a constant overall length at a predetermined position on the display screen based on the horizontal sawtooth wave signal from the horizontal scanning circuit and the vertical sawtooth wave signal from the vertical scanning circuit; a scale display means for displaying a reference scale and subscales for subdividing the reference scale on a reference line based on the voltage of the horizontal sawtooth signal and a reference voltage whose value changes according to changes in magnification; and the reference scale. 1. A magnification display device for a sample image, comprising character display means for displaying the total length of a line and the converted length on the sample of one division of a reference scale in characters.