JP2001006587A - Charged particle beam radiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce readjustment caused by an erroneous operation and thereby to improve operability by varying the relation between the operation amount of one or more operation means and the actuation amount of an adjustment function due to it according to a cumulated value of the operation amount or a period from the operation start. SOLUTION: A system control means 14 connected to various kinds of operation knobs of an adjustment operation panel 50 controls an electron beam control part 13 of an electron beam 3 from an electron source 2, and secondary electrons are displayed on an image display 22 through a secondary electron detector 9, an image memory 18 and the like. A focus rough adjustment knob 51 is effective only in the case of low magnification, and a focus fine adjustment knob 52 and X, Y astigmatic correction knobs 53, 54 can effectively be used for adjustment in the case of high magnification. The adjustment amounts with the knobs are prevented from varying at the initial operation stage, so that the adjusted state is not deviated even if other knobs are mistakingly touched. After operation for a predetermined period, the system control means 14 controls the variation of the adjustment so as to set it to a normal value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for operating means for performing focus adjustment, astigmatism correction, and other manual adjustment of a charged particle beam irradiation apparatus such as a scanning electron microscope. The control method of the operating means.

[0002]

2. Description of the Related Art In a charged particle beam irradiation apparatus such as a scanning electron microscope, there are portions for manual adjustment such as focus adjustment, astigmatism correction, and others. Taking focus adjustment as an example, the required focus change range is several tens of millimeters, and the fine adjustment step required at the highest magnification is 1 μm or less, which requires a very wide dynamic range. Adjustment can be easily performed by using two knobs and reducing the amount of change in focus per rotation angle as the magnification increases.

[0003]

In the conventional apparatus, there is a problem that the state of the adjustment is broken by erroneous operation. Taking focus adjustment as an example, the knobs for the coarse adjustment and the fine adjustment are often placed adjacent from the viewpoint of operability, and the focus adjustment is performed while watching the image,
Touching the coarse adjustment knob for fine adjustment may occur. In this case, the focus is greatly shifted, and it is necessary to perform the adjustment again from the beginning.
Also, for example, since astigmatism is a two-dimensional quantity,
Adjustment is required alternately with two knobs, and this operation requires skill. If the knob is accidentally touched, it takes time to readjust. Further, even after the adjustment is completed, if the user accidentally touches the knob, readjustment is required.

[0004] It is an object of the present invention to provide a charged particle beam irradiation apparatus such as a scanning electron microscope or the like in which operability is improved by reducing readjustment work caused by the erroneous operation as described above.

[0005]

SUMMARY OF THE INVENTION The present invention provides an apparatus incorporating protection means so that an adjusted state is not destroyed when another knob is accidentally touched. .

[0006] One method is to start the operation of the knob in such a manner that at the beginning of the operation of the knob, the adjustment amount by the knob does not change, and when the operation is continued, the change of the adjustment amount becomes a normal value. The change in the adjustment amount is controlled based on the accumulated value of the operation amount from the operation or the time from the start of the operation. In other methods, depending on conditions such as the current device status and operation history,
Restricts the operation of certain control knobs, for example,
When the magnification is equal to or more than a predetermined value, or once the focus fine adjustment knob is operated, the focus coarse adjustment knob is invalidated.
As a combination of the two, for example, when the magnification is equal to or more than a predetermined value, the operation of the coarse focus adjustment knob may be the first operation.

It is to be noted that operating means other than knobs, such as a slide type adjuster and an adjuster installed on a graphic user interface of a computer, are also required.
Similar control can be performed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a diagram showing an entire configuration of a scanning electron microscope according to an embodiment of the present invention. The scanning electron microscope main body 1 includes an electron source 2, a first converging lens 5, an astigmatism correction coil 6, a deflecting coil 7, a second converging lens 8,
It is constituted by a secondary electron beam detector 9 and the like, and is controlled by the scanning electron microscope controller 12. Scanning electron microscope controller 1
2 includes an electron beam control unit 13, an amplifier 15, an image memory 18, and a system control unit 14 for controlling each component. The computer 19 further includes a keyboard 20 as a character input device, a mouse 21 as a pointing device, and an image display 22 such as a cathode ray tube. As shown in FIG. 1B, the adjustment operation panel 50 is provided with operation knobs 51 to 59 for performing various adjustment operations.

The electron beam 3 emitted from the electron gun 2 is narrowed down by an electron beam stop 4, a first focusing lens 5, an astigmatism correction coil 6, a deflecting coil 7, and a second converging lens 8 to a sample 11. Irradiate while scanning. The control of these electron beams 3 is performed by the system control means 14 of the scanning electron microscope control device 12 controlling the electron beam control unit 13 composed of a high voltage power supply, a lens power supply, a deflection amplifier and the like. The focal position of the electron beam 3 irradiating the sample 11 is adjusted by controlling the second converging lens driving unit 13b and changing the current flowing through the second converging lens 8. Secondary electrons generated from the sample 11 by irradiation of the electron beam 3 are detected by the secondary electron detector 9, amplified by the amplifier 15, and input to the image memory 18. The image memory 18 converts the input signal into digital data by an A / D converter, forms image data on the memory from the signal of the detector input in synchronization with the scanning signal, and displays the image data on the image display 22. To be displayed. The operation knobs 51 to 59 of the adjustment operation panel 50 are used for operating the visual field movement, focusing, astigmatism correction, contrast, brightness, and magnification.
The system controller 14 detects the operation amount of the knob and controls the corresponding high-voltage power supply, lens power supply, deflection amplifier, etc., and moves the field of view, focuses, astigmatism correction, and contrast. Adjustment, brightness adjustment, and magnification setting are performed.

First, a method of invalidating the knob according to the state of the apparatus will be described. The focus coarse adjustment knob is enabled when the magnification is lower than a predetermined value, and disabled when the magnification is higher. At high magnifications, adjustment is possible with sufficient sensitivity with the fine adjustment knob. Conversely, astigmatism correction is disabled at low magnifications.
This is because a change in astigmatism cannot be observed unless the magnification is usually several thousand times or more, and aberrations tend to increase when operated at a low magnification. In addition, since it is difficult for ordinary operators to adjust the astigmatism correction unless the scanning speed is usually high, the astigmatism correction knob is disabled during observation at a low scanning speed. Since all of these states are set by the system control means 14, such control can be easily performed.

Next, at the beginning of the operation of the knob depending on the state of the apparatus, an operation sensitivity control is performed so that the adjustment amount by the knob does not change, and if the operation is continued, the change of the adjustment amount becomes a normal value. The method will be described. In this case as well, the conditions may be the same as in the above-mentioned case of invalidating, and instead of invalidating, the sensitivity of the knob may be controlled. It is also effective to control these controls based on the operation history of each knob. If the focus fine adjustment knob is operated after the coarse focus adjustment knob is operated,
This is a valid operation or a normal operation without operation sensitivity control. Conversely, after the focus fine adjustment knob is operated,
When the focus coarse adjustment knob is operated, it is invalidated or operation sensitivity control is performed so that the focus does not change only by the first operation. Hereinafter, at the beginning of the knob operation, operation sensitivity control that prevents the adjustment amount by the knob from changing, and if the operation is continued, changes the adjustment amount to the normal value, determines the current state of the device. Will be described in detail.

FIG. 2 is an example of a processing flow showing the flow of control of the focus coarse adjustment knob. The focus coarse adjustment knob is constituted by a rotary encoder, and generates a number of pulses in proportion to the rotation angle. The system control means 14 counts the pulses generated at regular intervals (for example, 10 mS),
Control is performed based on the count value. In step 204, an input of a coarse focus adjustment operation is waited. If there is an operation input (the count value is other than 0), in step 206, it is determined whether or not to perform the operation sensitivity control based on the apparatus state or the operation history described above. Do. If the determination condition is not satisfied, the operation sensitivity is set to the normal sensitivity in step 222. If the determination condition is satisfied, it is determined in step 208 whether the operation is a newly started operation or a part of a continuous operation at a time interval from the previous operation input, and the operation is a newly started operation. In this case, the operation sensitivity is cleared to 0 in steps 218 and 220, and a timer (TMw) for measuring the time (tw) from the start of the new operation is started. If the operation is a part of a continuous operation, in step 212, the operation sensitivity is set as a function f (tw) of the elapsed time so that the longer the elapsed time (tw) of the timer (TMw) is, the higher the operation sensitivity is. In step 214, the current of the second converging lens 8 is changed with the sensitivity determined and set as described above. In step 216, the timer (TMb) for measuring the time interval (tb) of the operation input is cleared, and the process returns to step 204.

FIG. 4 shows a change in the operation sensitivity to the operation of the knob when the processing flow of FIG. 2 is executed. The relationship between the elapsed time (tw) from the start of the new operation and the operation sensitivity is
The first fixed time (tw1) is a case where the sensitivity is 0, then the sensitivity is increased linearly, and then the sensitivity is fixed. At first, even when the knob is turned, the current of the second converging lens 8 does not change, and thereafter the operation sensitivity continuously increases. If the operation of the knob is stopped once and the operation is resumed before the time interval (tb) of the operation input reaches the predetermined value (tb1) as in operations 2, 4, and 6, a part of the continuous operation As a result, the operation sensitivity is not cleared,
Or it becomes a constant value. Like operations 3, 5, 7, and 8,
If the operation input is restarted after the time interval (tb) exceeds the predetermined value (tb1), the operation is regarded as a new operation and the sensitivity becomes zero.
The above operation is started from the state described above.

FIG. 3 shows a processing flow in the case where the control of the operation sensitivity, which has been performed with the passage of time in the above description, is performed with the cumulative value of the operation amount. At step 504, input of a coarse focus adjustment operation is waited. If there is an operation input, it is determined at step 506 whether or not operation sensitivity control is to be performed based on the apparatus state or operation history described above. If the conditions are not met, the operation sensitivity is set to the normal sensitivity in step 522. If the determination condition is satisfied, it is determined in step 508 whether the operation is a newly started operation or a part of a continuous operation based on a time interval from the previous operation input, and the operation is a newly started operation. In this case, the operation sensitivity is cleared to 0 in step 518, and in step 520, the counter for measuring the accumulated operation amount (m) from the start of the new operation is cleared. If it is part of a series of operations, step 512
The function f of the cumulative value of the operation amount is set so that the operation sensitivity increases as the cumulative value (m) of the operation amount from the start of the operation increases.
(M). In step 514, the current of the second converging lens 8 is changed with the sensitivity determined and set as described above. At step 516, the time interval of the operation input (t
clear the timer (TMb) for measuring b),
In step 524, the pulse count value is added to the cumulative operation amount counter value (m), and the process returns to step 204.

FIG. 5 shows the change in the operation sensitivity to the operation of the knob when the processing flow of FIG. 3 is executed. The relationship between the accumulated operation amount (m) and the operation sensitivity is a case where the sensitivity is 0 until the first constant operation amount (m1), then the sensitivity is increased linearly, and then the sensitivity is constant. At first, even when the knob is turned, the current of the second converging lens 8 does not change, and thereafter the operation sensitivity continuously increases. Operations 2, 4,
As shown in FIG. 6, if the operation of the knob is stopped and then restarted before the time interval (tb) of the operation input reaches the predetermined value (tb1), it is regarded as a part of the continuous operation, The previous operating sensitivity continues. Operations 3, 5, 7, 8
, The time interval (tb) of the operation input is a predetermined value (tb
When the operation is resumed after exceeding 1), the operation is regarded as a new operation, and the above operation is started from the state of zero sensitivity.

According to the above-described method, an undesired change in the state when the knob is operated by mistake can be reduced, and a device with good operability can be obtained.

Steps 212 and 2 in FIGS.
The function for setting the sensitivity in 512 is a combination of the elapsed time from the start of the operation and the accumulated amount of operation, for example, the dead period from the start of the operation is the elapsed time from the start of the new operation,
The period during which the sensitivity is increased thereafter may be used as a function of the accumulated operation amount. The initial sensitivity is not 0, and may be started from a low sensitivity. Further, the operating conditions of the sensitivity control, the function for setting the sensitivity, the time tb1, the operating sensitivity at the start, and various parameters such as the operating means to which the sensitivity control is applied are set on a setting screen as shown in FIGS. If a plurality of combinations are used to register and selectively apply, a more easy-to-use device can be realized.

FIG. 8 is an example of an operation screen created on the graphic user interface of the computer 19. An image display area 61 on the image display 22, a slide bar 62 for coarsely adjusting the focus, a slide bar 63 for finely adjusting the focus, and a slide bar 6 for adjusting astigmatism correction
4, 65, slide bar 66 for adjusting brightness,
A slide bar 67 for adjusting the contrast, a magnification adjustment slide bar 68, a magnification display area 69, and a mouse cursor 60 are displayed. The operation amounts of these slide bars are recognized by the computer 19, sent to the system control means 14, and the same operation as the operation by the operation knob described above can be performed. The control of the operation sensitivity described above can be applied to such a configuration in exactly the same manner.

[0019]

According to the present invention, by disabling the knob or changing the operation sensitivity with time according to the state of the apparatus and the operation history, it is possible to reduce the undesired change of the apparatus state due to an accidental erroneous operation. It can be a good device.

[Brief description of the drawings]

FIG. 1A is an overall configuration diagram of a scanning electron microscope according to an embodiment of the present invention, and FIG. 1B is a diagram illustrating an adjustment operation panel and various adjustment knobs.

FIG. 2 is a diagram showing a control flow according to the embodiment of the present invention.

FIG. 3 is a diagram showing another control flow according to the embodiment of the present invention.

FIG. 4 is a diagram showing an example of a change in operation sensitivity when a knob is operated under the control of the control flow of FIG. 2;

FIG. 5 is a diagram illustrating an example of a change in operation sensitivity when a knob is operated under control by the control flow of FIG. 3;

FIG. 6 is a view showing an example of a screen for setting operation sensitivity control.

FIG. 7 is a view showing an example of a screen for performing detailed settings of the operation sensitivity control of FIG. 6;

FIG. 8 is a diagram showing an operation screen of another adjusting means according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scanning electron microscope main body, 2 ... Electron source, 3 ... Electron beam, 4 ... Electron beam stop, 5 ... First converging lens, 6 ...
Astigmatism correction coil, 7: deflection coil, 8: second converging lens, 9: secondary electron detector, 11: sample, 12: scanning electron microscope controller, 13: electron beam controller, 13a
... Astigmatism correction coil drive unit 13b Second convergent lens drive unit 14 System control means 15 Amplifier 18
... Image memory, 19 ... Computer, 20 ... Keyboard, 21 ... Mouse, 22 ... Image display, 50 ... Adjustment control panel, 51 ... Coarse focus adjustment knob, 52 ... Focal fine adjustment knob, 53 ... X astigmatism correction knob 54 ... Y astigmatism correction knob, 55 ... brightness adjustment knob, 56 ... contrast adjustment knob, 57 ... X visual field movement knob, 58 ... Y
Field of view moving knob, 59: magnification adjustment knob, 60: mouse cursor, 61: image display area, 62: focus coarse adjustment slide bar, 63: focus fine adjustment slide bar, 64: X astigmatism correction slide bar, 65: Y non Point correction slide bar,
66: a slide bar for brightness adjustment; 67: a slide bar for contrast adjustment; 68: a slide bar for magnification adjustment; 69: a magnification display area.

Claims (7)

[Claims] 1. An electron optical system provided for irradiating a charged particle beam onto a sample, a detection system for detecting secondary electrons and other signals generated from the sample, and a display unit for displaying the detected signal. A charged particle beam irradiation apparatus comprising one or more operating means for performing an adjusting operation, wherein one or more predetermined adjusting functions are operated by operating the operating means. The relationship between the operation amount of the adjustment function and the operation amount of the adjustment function is determined by calculating the cumulative value of the operation amount of the operation means or
A charged particle beam irradiation apparatus characterized by being variable depending on the time from the start of operation. 2. An electron optical system provided for irradiating a charged particle beam onto a sample, a detection system for detecting secondary electrons and other signals generated from the sample, and a display unit for displaying the detected signals. A charged particle beam irradiation apparatus comprising: one or a plurality of operating means for performing an adjusting operation; and operating one or a plurality of predetermined adjusting functions by operating the operating means. Depending on the current state of the system,
A charged particle beam irradiation apparatus comprising means for invalidating or enabling the operation of a corresponding adjustment function by operation of the specific operation means. 3. An electron optical system provided for irradiating a charged particle beam onto a sample, a detection system for detecting secondary electrons and other signals generated from the sample, and a display unit for displaying the detected signals. A charged particle beam irradiation apparatus comprising: one or a plurality of operating means for performing an adjusting operation; and operating one or a plurality of predetermined adjusting functions by operating the operating means. Depending on the current state of the system,
The relationship between the operation amount of the operation means and the operation amount of the adjustment function is
A charged particle beam irradiation apparatus, comprising: means for changing. 4. An electron optical system provided for irradiating a charged particle beam onto a sample, a detection system for detecting secondary electrons and other signals generated from the sample, and a display unit for displaying the detected signals. A charged particle beam irradiation apparatus comprising one or a plurality of operating means for performing an adjusting operation, wherein one or a plurality of predetermined adjusting functions are operated by operating the operating means. With the operation history of, the operation of the corresponding adjustment function by the specific operation means is invalidated,
Alternatively, there is provided a charged particle beam irradiation apparatus comprising means for making it effective. 5. An electron optical system provided for irradiating a charged particle beam onto a sample, a detection system for detecting secondary electrons and other signals generated from the sample, and a display unit for displaying the detected signals. A charged particle beam irradiation apparatus comprising one or a plurality of operating means for performing an adjusting operation, wherein one or a plurality of predetermined adjusting functions are operated by operating the operating means. A charged particle beam irradiation apparatus comprising means for changing the relationship between the amount of operation of the operation means and the amount of operation of the adjustment function based on the operation history of (1). 6. The charged particle beam irradiation apparatus according to claim 1, wherein the operating condition of the operation sensitivity control, the rate of change of the operation sensitivity, or the operation means for applying the sensitivity control. A charged particle beam irradiation apparatus comprising means for allowing an operator to arbitrarily set at least one of them. 7. The charged particle beam irradiation apparatus according to claim 1, wherein the operation sensitivity control includes focus adjustment, astigmatism correction, brightness adjustment of an observation image, contrast adjustment, electromagnetic field of view. A charged particle beam irradiation apparatus characterized in that the apparatus is applied to at least one manual adjustment operation means among the movement functions.