JP2000100366A - Scanning electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately locate an optimum visual field in a short time at an intended scaling factor by providing a means for setting up a movement area of a stage, for continuously scanning the stage two-dimensionally, and for stopping the stage at an arbitrary position. SOLUTION: The moving direction of a stage is selected from among three kinds, the horizontal direction, the vertical direction, and the spiral direction. The magnification for search for a visual field is et up, and the coarseness of continuous movement of the stage is determined. An operator locates an object visual field while observing an image on an image display part 18. The present position of the stage and the locus of its movement are displayed in a matrix. When the object visual field is found and a click operation is performed, a cell designated is solidly colored. Next, magnification is automatically changed to a higher magnification, the stage is continuously moved in an area of the designated cell. The operator searches for an optimum observation visual field at the high magnification, while observing the image. When the optimum visual field is found, the movement of the stage is stopped by pressing a stop button, and the operator conducts detail observation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope.

[0002]

2. Description of the Related Art In order to search a desired optimum visual field at a desired magnification in a scanning electron microscope, the following operation is performed using a graphical user interface function.

[0003] 1. Search for the target observation field of view while moving the stage over a wide area at low magnification.

[0004] 2. After finding the desired field of view, stop the stage.

[0005] 3. Change to a higher magnification.

[0006] 4. The stage is moved little by little in order to match the target observation field of view at high magnification.

[0007] 5. Stop the stage at the position of the field of view that seems to be optimal.

[0008] 6. Search for the optimal observation field of view while gradually increasing the magnification.

The operations 1 to 6 are repeated, and observation is performed while displaying the optimal visual field at the desired magnification on the image display unit.

There are the following operation methods for moving the stage.

1. Move the stage by operating the stage control screen.

2. Move the stage by pressing the up, down, left and right buttons in the screen.

3. The pointer of the pointing device for moving the stage is displayed on the display, and the stage is moved by dragging and dropping the pointing device.

[0014]

In order for an operator to search for a desired optimum visual field at a desired magnification from within a sample within a magnification range of 200,000 to 500,000, the operator frequently changes the magnification and moves the stage. In addition, it is necessary to repeat very troublesome work and to waste a lot of time.

An object of the present invention is to provide a scanning electron microscope capable of easily performing a task of frequently changing a magnification and moving a stage, so that an optimum visual field can be accurately searched at a desired magnification in a short time. It is in.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a semiconductor device comprising:
The purpose of the present invention is to accurately search a target optimum visual field at a target magnification within a magnification range of 500,000. First, the entire stage is continuously moved at a low magnification, and the pointing device is operated at a target observation position. After the operation, the magnification is automatically changed to the high magnification, and the designated range is further continuously moved, so that the optimum visual field can be accurately searched at the high magnification.

To achieve the above object, an electron beam is scanned and irradiated on a sample, and an image memory for taking in a secondary electron signal generated from the sample as an image signal, and a scanning width for switching the electron beam scanning width. A magnification switching unit, a display for displaying the captured image signal in an image display area, a moving mechanism for moving the sample in at least the X direction and the Y direction by driving a motor, and a stage controller for controlling the motor. A scanning electron microscope having stage designating means for designating a moving range of the stage, and stage scanning driving means for continuously scanning the stage two-dimensionally by moving the stage in the X and Y directions within the designated range; A configuration is provided in which stage stop means for stopping the stage driving at an arbitrary position during the stage scanning driving is provided. Furthermore, the above object can be achieved by setting the method of moving the continuous stage, setting the magnification of the visual field search (low magnification, high magnification), and setting the moving speed of the continuous stage.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention for searching for an optimum observation visual field formed on a sample.

FIG. 1 is a configuration diagram of a scanning electron microscope of the present invention.

The electron beam 3 emitted from the electron gun 2 at the upper end of the mirror 1 evacuated is converted into a sample 6 by a converging lens system 4.
Converges.

The electron beam 3 is two-dimensionally scanned on the sample by the scanning coils 5X and 5Y. Scan coil 5X, 5Y
Are supplied with scanning signals from the horizontal scanning signal generator 7 and the vertical scanning signal generator 8. Further, the signal detected by the secondary electron detector 9 is supplied to the image memory 10 as a luminance signal. By synchronizing these two signals, a scanned image of the sample 6 is displayed on the image display unit 18 of the display 11.

The sample 6 is mounted on a sample moving table 12. The sample moving table 12 is moved in the X-axis direction and the Y-axis direction in the vertical plane of the electron beam 3 by an X-axis moving mechanism 13X and a Y-axis moving mechanism 13Y. It is to be moved in the direction. The X-axis and Y-axis signal generation circuits 15X and 15Y connected to the stage controller 14 generate signals in accordance with instructions from the stage controller 14. Therefore, the X-axis and Y-axis motors 13X and 13X
The sample moving table 12 is moved through Y. The stage controller 14 generates a signal based on a driving command from the computer 17 by operating the pointing device 16.

Next, processing up to searching for an optimal visual field at a target magnification will be described with reference to the processing flow of FIGS. 2 to 6 and FIG.

The operator clicks on a menu bar (Stage) of the main screen (FIG. 2) displayed on the display. After the click operation, a continuous stage movement setting screen shown in FIG. 3 is displayed. First, the stage moving method is set (A1). It can be selected from three types of continuous movement in the horizontal direction, continuous movement in the vertical direction, and continuous movement in the spiral direction. Next, a magnification for searching the visual field is set. The magnification setting includes a low magnification setting for searching the entire stage range and a high magnification setting for searching the designated cell range. By setting these magnifications, the roughness of the continuous stage movement can be determined (A2).

In order to display the field of view when the stage is continuously moved on the image display unit without omission, the number of rows and columns of the matrix is calculated from the sample size, the size of the image display unit, and the set values of the magnification. Once determined, the matrix can be displayed on the display. For example, if the sample size is
Assuming that Sy, the size of the image display unit is Dx, Dy, and the set magnification value is m, the matrix (number of rows) and (number of columns) can be obtained by the following equations.

[0026]

Equation 1 matrix (number of rows) = Sx / (Dx / m)

[0027]

## EQU2 ## matrix (number of columns) = Sy / (Dy / m) Speed in FIG. 3 sets the moving speed (A3) of the stage. The Set button in FIG. 3 determines the above settings. When the Set button is pressed (A4), the display shows the entire stage range matrix (low magnification), the designated cell range matrix (high magnification) and the + cursor indicating the current stage position (A5) on the display.

The setting information is transferred to the stage controller. After automatically moving the stage to the initial position in FIG. 5 (A6), the stage controller calculates the roughness of moving the stage, the stage moving speed at low magnification, and the stage moving speed at high magnification from the transferred information. Then, it is converted into a control signal for stage movement. The stage moving speed at low magnification can be determined by the set value, but the stage moving speed at high magnification is calculated. For example, if the low magnification value is Lm, the high magnification value is Hm, and the stage moving speed at low magnification is Vl, the stage moving speed Vh at high magnification is Vh = Vl ×
(Lm / Hm). When the magnification is changed to a high magnification, it is changed from Vl to Vh. Thereby, even at a high magnification, it is possible to observe with the same speed image as the moving speed observed at a low magnification.

Thereafter, the process waits until a stage movement start command is received from the computer. The Start button is for starting continuous stage movement. FIG. 5 shows the state of continuous stage movement. First, the magnification is automatically changed to a low magnification (A8). Next, continuous movement of the entire stage is started (A9).

The operator searches for a target visual field while observing the image displayed on the image display section of FIG.
During the movement of the stage, as shown in FIG. 4, a locus of movement is displayed in a matrix together with a + cursor display indicating the current stage position. When a target visual field is found, a click operation (A10) is performed. When this click operation is performed, the inside of the designated cell is filled with a color, and the designated cell is clarified.

Next, the magnification is automatically changed from the low magnification to the high magnification (A11). Next, a continuous stage movement (A12) within the specified cell range is performed. The operator searches for the optimal observation field of view at high magnification while observing the image displayed on the image display unit in FIG. If you find the optimal field of view,
By pressing the Stop button (A13), the stage movement is stopped (A14). Thereafter, the operator observes in detail.

To resume the continuous stage movement, use Star
t Press the button. After the observation of the visual field in the designated cell is completed, the magnification is returned to the low magnification again, and the continuous stage is moved from the previously clicked position. A8 to A13 in the processing flow of FIG. 7 are automatically performed until the search of the entire stage range is completed.

According to the present embodiment, within the magnification range of 20 to 500,000 times, the magnification change and the continuous stage movement for searching for the desired optimal visual field at the desired magnification from within the sample are performed automatically. , Operator's work is greatly reduced. In addition, since the continuous stage movement within the range limited to the entire range of the stage is performed stepwise, the visual field can be found accurately.

[0034]

As described above, according to the present invention, 20 to 5
Since the magnification change and the continuous stage movement are automatically performed when searching for the desired optimum visual field from the sample at the desired magnification within the magnification range of 100,000, the work of the operator can be greatly reduced.

As for the continuous stage movement, since the continuous stage movement is performed stepwise within the entire range of the stage and within a limited range, the visual field can be accurately found. Also, by displaying the current stage position and the locus of the stage movement on the display, the stage position and the locus can be visually grasped.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a scanning electron microscope of the present invention.

FIG. 2 is a diagram showing a main screen display for realizing the present invention.

FIG. 3 is a diagram showing a stage movement setting screen.

FIG. 4 is a diagram showing a matrix display when the stage is moved.

FIG. 5 is a view showing a state in which the entire stage is moved.

FIG. 6 is a diagram showing a specified cell range moving state.

FIG. 7 is a processing flow of an optimum visual field search.

[Explanation of symbols]

1 ... mirror body, 2 ... electron gun, 3 ... electron beam, 4 ... converging lens,
5X, 5Y scanning coil, 6 sample, 7 horizontal scanning signal generator, 8 vertical scanning signal generator, 9 secondary electron detector, 10 image memory, 11 display, 12 sample moving table, 13X: X-axis moving mechanism, 13Y: Y-axis moving mechanism, 14: Stage controller, 15X: X-axis motor, 15Y: Y-axis motor, 16: pointing device, 17: computer, 18: image display unit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mitsugu Sato 882 Momo, Oaza, Hitachinaka-shi, Ibaraki Prefecture F-term in Hitachi Measuring Instruments Division (Reference) 5C001 AA03 CC04

Claims (11)

[Claims] 1. An image memory for scanning and irradiating a sample with an electron beam to capture a secondary electron signal generated from the sample as an image signal, a magnification switching means for switching a scanning width of the electron beam, and a captured image A display for displaying a signal in an image display area, a moving mechanism for moving the sample in at least the X direction and the Y direction by driving a motor,
In a scanning electron microscope having a stage controller for controlling the motor, there is provided a designating means for designating a moving range of the stage, and X and Y of the stage are set within the designated range.
A scanning electron microscope comprising: a stage scanning drive unit that continuously scans a stage two-dimensionally by moving in a direction; and a stage stop unit that stops the stage driving at an arbitrary position during the stage scanning drive. 2. A scanning electron microscope according to claim 1, further comprising setting means for setting a continuous stage moving method. 3. The scanning electron microscope according to claim 1, wherein the moving range of the stage is designated by displaying a beam scanning image of the sample and specifying an area on the image. 4. The scanning electron microscope according to claim 1, wherein the moving range of the stage is specified by displaying an optical microscope image of a sample taken in advance and specifying an area on the image. 5. The scanning electron microscope according to claim 1, wherein the moving range of the stage is designated by a range of stage coordinates. 6. The scanning electronic device according to claim 1, wherein the two-dimensional scanning of the stage is performed by designating at least two or more types of stages. microscope. 7. The display device according to claim 1, wherein the speed of the stage scanning drive or the roughness of the movement is determined by displaying a display field determined by a magnification of a display image in a display area. A scanning electron microscope characterized by being determined as follows. 8. The scanning electron microscope according to claim 1, further comprising means for marking a current stage position on said display. 9. The scanning electron microscope according to claim 1, further comprising means for marking a locus of the current stage movement on said display. 10. The scanning electron microscope according to claim 1, further comprising means for automatically changing a magnification by operating a pointing device while moving the continuous stage. 11. The scanning electron microscope according to claim 10, wherein the speed and roughness of the stage movement are automatically changed to a state in which images are displayed all over at the changed magnification in conjunction with the magnification change. A scanning electron microscope characterized by the fact that: