JP2003324135A - Electron-beam pattern inspecting apparatus and pattern inspecting method using electron beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron-beam pattern inspecting apparatus capable of obtaining an optimum inspecting condition in a short period of time, and an inspecting method using an electron beam. <P>SOLUTION: In the electron-beam pattern inspecting apparatus where a sample is inspected by using images obtained by irradiating the sample with the electron beam, or the inspecting method using the electron beam, a plurality of set values relating to the conditions for irradiating the electron beam are set so as to use predetermined reference values corresponding to separate set items, and for one set value among the set values, a value selected in a predetermined range is applied. While the set values except for one value and the selected value are applied, the sample is irradiated with the electron beam to obtain the images, and one set value among the set values is determined in the predetermined range based on the obtained images. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device such as a memory having a fine circuit pattern, a semiconductor device such as an LSI, a circuit pattern such as a liquid crystal or a photomask, and an inspection method, and particularly to an inspection device using an electron beam. Regarding inspection method.

[0002]

2. Description of the Related Art A semiconductor device is manufactured by repeating a process of transferring a circuit pattern formed on a semiconductor wafer by a photomask by a lithography process and an etching process. The quality of the lithography process, the etching process, and other processes that are manufacturing processes of semiconductor devices,
The generation of foreign matter in the manufacturing process greatly affects the yield of semiconductor devices. Therefore, in order to detect the occurrence of processing abnormalities and defects early or in advance, it is necessary to inspect the pattern formed on each step of the semiconductor wafer in the manufacturing process.

In the process of manufacturing a semiconductor device, an optical visual inspection apparatus for determining an abnormality using an image obtained by irradiating a pattern with a laser beam or the like, or a pattern is scanned with a charged particle beam such as an electron beam. Various inspection devices are actually used to determine anomalies from secondary electrons and backscattered electrons generated by using signal intensity and images.

As an example of an optical inspection apparatus for inspecting a defect existing in a pattern on a semiconductor wafer, a semiconductor wafer is irradiated with white light and a defect for comparing circuit patterns of the same kind of a plurality of LSIs using an optical image is compared. Inspection equipment is known, and its outline is the magazine "Monthly Semiconductor World" 1
August 995, pp. 96-99.

When a semiconductor wafer is inspected in the manufacturing process by such an optical inspection method, it is not possible to detect a residue or a defect of a pattern having a silicon oxide film or a photosensitive photoresist material on the surface, through which light is transmitted. It was In addition, it was not possible to detect an etching residue or a non-opening defect of a minute conductive hole, which is lower than the resolution of the optical system. Furthermore, the defect generated at the bottom of the step of the wiring pattern could not be detected.

As described above, with the miniaturization of circuit patterns, the complicated circuit pattern shapes, and the diversification of materials, it has become difficult to detect defects by an optical image. Therefore, a charged particle beam having a higher resolution than an optical image, In particular, a method of comparing and inspecting a circuit pattern using an image acquired by scanning with an electron beam has been proposed. In order to obtain a practical inspection time when comparing and inspecting circuit patterns by electron beam images, it is necessary to acquire images at a much higher speed than observation by a scanning electron microscope (SEM). There is. Then, it is necessary to secure the resolution of the image acquired at high speed and the SN ratio of the image.

As an example of a pattern comparative inspection apparatus using such an electron beam, reference J. Vac. Sci. Tech. B, Vol.
9, No.6, pp.3005-3009 (1991), Reference J. Vac. Sci. Tec
h. B, Vol. 10, No. 6, pp. 2804-2808 (1992), and Japanese Patent Publication No. 5-258703 and USP 5,502,
100 times more than normal SEM for 306 (10 nA or more)
An image formed from the signal by irradiating a conductive substrate (X-ray mask, etc.) with an electron beam having the electron beam current of any of the above, and detecting any or a plurality of secondary electrons, reflected electrons, or transmitted electrons generated. There is described a method of automatically detecting a defect by performing a comparative inspection of.

Further, it is difficult to obtain a high-resolution image due to the space charge effect with an electron beam with a large current and a low acceleration.
JP-A-258703 describes a method of decelerating a high-acceleration electron beam immediately before the sample and irradiating the sample with a substantially low-acceleration electron beam.

As a method for acquiring an electron beam image at high speed, there is a method of continuously irradiating an electron beam on a semiconductor wafer on the sample table while continuously moving the sample table to obtain an electron beam image.
It is described in JP-A No. 160948 and JP-A No. 5-258703.

In the inspection apparatus using the SEM as described above, it is important to set the following parameters,
It takes a considerable amount of time to derive the optimum inspection conditions, and the prior art does not consider this point.

(1) Setting of acceleration voltage value of electron beam (2) Current value setting of electron beam (3) Setting the number of additions of image signals (4) Pixel size setting (5) Scanning direction setting of electron beam

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide an electron beam accelerating voltage, an electron beam current, a number of signal additions,
When setting the inspection conditions in the pixel size and scanning direction of the electron beam, the image signal of the sample when each parameter is changed is automatically acquired, and the optimum inspection conditions can be set in a short time by the contrast of the image. An object of the present invention is to provide an inspection apparatus and an inspection method using an electron beam that can be obtained.

[0013]

In order to achieve the above object, an embodiment of the present invention is directed to irradiating a sample having a pattern with an electron beam to detect secondary charged particles and acquiring an image to obtain an image. In an electron beam type pattern inspection method for detecting a defect of the pattern of the sample using an image, a plurality of set values regarding conditions when irradiating the electron beam is set as reference values corresponding to respective preset values, and One of the set values is selected from a predetermined range, and the sample is irradiated with the electron beam to obtain the image according to the set value other than the one value and the selected value. One of the set values is determined from the predetermined range based on the acquired image.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the outline of the configuration of an SEM type appearance inspection apparatus for inspecting a pattern of a semiconductor wafer, a mask or a reticle using an electron beam to which the present invention is applied. The SEM type visual inspection device 1 is roughly divided into
The inspection chamber 2 includes an electron optical system device 3, an optical microscope unit 4, and a sample chamber 8, an image processing unit 5, a control unit 6, and a secondary electron detection unit 7.

The electron optical system device 3 includes an electron gun 10, an electron beam extraction electrode 11, a condenser lens 12, a blanking deflector 13, a diaphragm 14, a scanning deflector 15, and an objective lens 1.
6, a reflection plate 17, and an ExB deflector 18, and an electron beam 19 generated by the electron gun 10 and extracted by the extraction electrode 11 irradiates the sample 9 through the condenser lens 12, the diaphragm 14, and the objective lens 16. To be done. The electron beam 19 is a beam that is narrowed down and is scanned by the scanning deflector 15
And the sample 9 generates backscattered electrons and secondary electrons 51. The secondary electrons have their trajectories bent by the ExB deflector 18 and irradiate the reflector 17 to generate second secondary electrons 52, which are detected by the secondary electron detector 20. On the other hand, by directing the electron beam 19 to the outside of the aperture of the diaphragm 14 by the blanking deflector 13, irradiation of the sample 9 with the electron beam 19 can be prevented.

The sample chamber 8 includes a sample table 30 and an X stage 3
1, a Y stage 32, a rotary stage 33, a position monitor length measuring device 34, and a sample height measuring device 35. The optical microscope unit 4 is installed in the vicinity of the electron optical system device 3 in the room of the examination room 2 and at a position away from each other to the extent that they do not affect each other. The distance is known. And X stage 3
The 1 or Y stage 32 reciprocates a known distance between the electron optical system device 3 and the optical microscope unit 4.

The optical microscope unit 4 is composed of a white light source 40, an optical lens 41, and a CCD camera 42. Although not shown, the acquired image is sent to the image processing unit 5 as in the case of an electron beam image described later. To be

As the position monitor length measuring device 34, a length measuring device by laser interference is used in this embodiment. X stage 31,
The positions of the Y stage 32 and the rotary stage 33 can be monitored in real time, and the position information can be sent to the control unit 6. Although not shown, the X stage 31, Y
Similarly, data such as the number of rotations of the motors of the stage 32 and the rotary stage 33 is configured to be sent from each driver to the control unit 6. Based on these data, the control unit 6 can accurately grasp the area and the position where the electron beam 19 is irradiated, and correct the positional deviation of the irradiation position of the electron beam 19 in real time if necessary. It can be corrected by using the control circuit 43. Even if the sample 9 is replaced, the area irradiated with the electron beam can be stored for each sample.

As the sample height measuring instrument 35, an optical measuring instrument which is a measuring method other than the electron beam, for example, a laser interferometer or a reflected light measuring instrument for measuring a change in the position of reflected light is used. The height of the sample 9 mounted on the X stage 31 and the Y stage 32 can be measured in real time. In this embodiment, a long white light that has passed through a slit is irradiated onto a sample 9 through a transparent window, the position of reflected light is detected by a position detection monitor, and the amount of change in height is calculated from the position change. Was used. Based on the measurement data of the sample height measuring instrument 35, the focal length of the objective lens 16 for narrowing down the electron beam 19 is dynamically corrected, so that the inspected area can always be irradiated with the focused electron beam 19. It has become. It is also possible to measure the warpage and height distortion of the sample 9 before the electron beam irradiation, and to set the correction condition for each inspection region of the objective lens 16 based on the data. .

In order to obtain an image of the sample 9, the sample 9 is irradiated with a narrowed electron beam 19 to generate secondary electrons 51, which are scanned by the electron beam 19 and the X stage 3 is used.
1, it is detected in synchronization with the movement of the Y stage 32.

The electron beam 19 is generated by the electron gun 10 and the extraction electrode 11.
It is extracted from the electron gun 10 by applying a voltage between and. The electron beam 19 is accelerated by applying a high voltage negative potential to the electron gun 10. As a result, the electron beam 1
9 advances toward the sample stage 30 with energy corresponding to the potential, is converged by the condenser lens 12, is further narrowed down by the objective lens 16, and is narrowed down by the X stage 31, Y stage 32, and rotary stage 33 on the sample stage 30. The sample 9 mounted above is irradiated.

The blanking deflector 13 has a scanning signal generator 44 for generating a scanning deflection signal and a blanking signal.
The objective lens power supply 45 is connected to the objective lens 16. Sample 9 has a retarding power supply 36
This allows a negative voltage to be applied. By adjusting the voltage of the retarding power source 36, the primary electron beam can be decelerated, and the electron beam irradiation energy to the sample 9 can be adjusted to an optimum value without changing the potential of the electron gun 10. When it is necessary to blank the electron beam 19, the blanking deflector 13 deflects the electron beam 19 so that the electron beam 19 can be controlled so as not to pass through the diaphragm 14.

The secondary electrons 51 generated by irradiating the sample 9 with the electron beam 19 are accelerated by the negative voltage applied to the sample 9. The ExB deflector 18 is arranged above the sample 9, and the secondary electrons 51 accelerated by this are deflected in a predetermined direction. The deflection amount can be adjusted by the voltage applied to the ExB deflector 18 and the strength of the magnetic field. Further, this electromagnetic field can be varied in association with the negative voltage applied to the sample. The secondary electrons 51 deflected by the ExB deflector 18 are reflected by the reflector 1 under a predetermined condition.
Clash with 7. This reflector 17 has a conical shape,
The electron beam 19 passes through the opening provided in the center.
When the accelerated secondary electrons 51 collide with the reflection plate 17, second secondary electrons 52 having an energy of several V to 50 eV are generated from the reflection plate 17.

The secondary electron detector 20 is arranged above the objective lens 16 in the inspection room 2 to detect the second secondary electron 52, and the output signal of the secondary electron detector 20 is the output signal of the inspection room 2. The AD converter 22 is amplified by the preamplifier 21 installed outside.
Is converted into digital data by the optical conversion means 23 to the optical transmission means 24, and the electrical conversion means 25 of the image processing unit 5
Sent to. If the reflector 17 is not provided, the secondary electron 51 may be detected by the secondary electron detector 20 instead of the second secondary electron 52.

The high-voltage power supply 26 is a preamplifier drive power supply 27 for driving the preamplifier 21, and an A for driving the AD converter 22.
A D converter drive power supply, and a power supply to a reverse bias power supply 29 that supplies a voltage applied to the secondary electron detector 20 to attract the second secondary electrons. The second secondary electrons 52 generated by colliding with the reflection plate 17 are guided to the secondary electron detector 20 by the attraction electric field generated in the secondary electron detector 20 by the supply of the reverse bias power source 29.

The secondary electron detector 20 is a second secondary electron generated when the secondary electron 51 generated while the electron beam 19 is irradiated on the sample 9 is accelerated and then collides with the reflector 17. 52 is detected in conjunction with the scanning timing of the electron beam 19.

The output signal of the secondary electron detector 20 is amplified by the preamplifier 21 installed outside the inspection room 2 and becomes digital data by the AD converter 22. AD converter 22
Is configured to convert the analog signal detected by the secondary electron detector 20 into a digital signal immediately after being amplified by the preamplifier 21 and transmit the digital signal to the image processing unit 5. In this way, since the detected analog signal is digitized and transmitted immediately after detection, it is possible to obtain a high-speed signal with a high SN ratio.

The sample 9 is mounted on the X stage 31 and the Y stage 32, and the X stage 31,
A method of linearly scanning the electron beam 19 in the X direction such that the Y stage 32 is continuously moved in the Y direction at a constant speed, and the X stage 31 and the Y stage 32 are continuously moved in the X direction at a constant speed. It is possible to select one of the methods of linearly scanning the electron beam 19 in the Y direction while moving.

The image processing section 5 is composed of a first storage section 46, a second storage section 47, a calculation section 48, a defect determination section 49, and a monitor 50. The captured electron beam image or optical image is displayed on the monitor 50. The operation command and operation condition of each part of the device are input and output from the control part 6. In the control unit 6, conditions such as an acceleration voltage at the time of electron beam generation, an electron beam deflection width, a deflection speed, a signal acquisition timing of the secondary electron detector 20 and a moving speed of the sample table 30 are arbitrarily set according to the purpose. It is input to or to select and set. The control unit 6 uses the correction control circuit 43 to monitor the position and height deviations from the signals of the position monitor length measuring device 34 and the sample height measuring device 35, and generates a correction signal from the result, and generates an electron beam. The correction signal of the objective lens 16 is sent to the objective lens power supply 45 and the correction signal of the blanking deflector 13 is sent to the scanning signal generator 44 so that 19 is always irradiated to the correct position.

The image processing section 5 is composed of a first storage section 46, a second storage section 47, a calculation section 48, a defect determination section 49, and a monitor 50. The image signal of the sample 9 transmitted by the optical fiber 24 is converted into an electric signal again by the electric conversion means 25 and then stored in the first storage unit 46 or the second storage unit 47.

The arithmetic section 48 performs various image processings for aligning the stored image signal with the image signal of the other storage section, standardizing the signal level, and performing various image processings for removing noise signals, and outputs both images. Comparing the signals.

The defect determining section 49 compares the absolute value of the difference image signal calculated by the calculating section 48 with a predetermined threshold value, and if the difference image signal level is higher than the predetermined threshold value, the pixel is a defect candidate. Then, the position, the number of defects, etc. are displayed on the monitor 50. This predetermined threshold is called an inspection threshold.

Although the secondary electron detector 20 is applied with the reverse bias voltage by the reverse bias power supply 29 in the above embodiment, it may be configured so that the reverse bias voltage is not applied. In addition, in this embodiment, the secondary electron detector 20 has a PI
Although the N-type semiconductor detector is used, another type of semiconductor detector, such as a Schottky type semiconductor detector or an avalanche type semiconductor detector, may be used. Further, if conditions such as responsiveness and sensitivity are satisfied, MCP (micro channel plate) can be used as a detector.

Next, a case where a semiconductor wafer patterned in the manufacturing process is inspected by the SEM type visual inspection apparatus 1 shown in FIG. 1 will be described with reference to FIG.

The sample 9 is loaded into a sample exchange chamber (not shown). The sample 9 is mounted on a sample holder (not shown) and held and fixed, and then the sample exchange chamber is evacuated. When the sample exchange chamber reaches a certain degree of vacuum, it is transferred to the inspection chamber 2.
In the inspection room 2, the sample holder is placed on the sample table 30 via the X stage 31, the Y stage 32, and the rotary stage 33, and is held and fixed.

The sample 9 is placed at a predetermined first coordinate below the optical microscope unit 4 by moving the X stage 31 and the Y stage 32 in the X and Y directions based on a predetermined inspection condition registered in advance. The monitor 50 observes an optical microscope image of the circuit pattern formed on the sample 9. Then, the position correction value of the first coordinate is calculated by comparing with the equivalent circuit pattern image stored in advance for the position rotation correction. Next, move a certain distance from the first coordinate and move to the second coordinate where the circuit pattern equivalent to the first coordinate exists. Similarly, the optical microscope image is observed and the position rotation correction is performed. Is compared with the circuit pattern image stored in
The position correction value of the second coordinate and the amount of rotation deviation with respect to the first coordinate are calculated. The rotary stage 33 rotates and corrects by the calculated rotation deviation amount.

In this embodiment, the rotation deviation is corrected by the rotation of the rotary stage 33.
The rotation deviation amount can also be corrected by a method in which the scanning deflection position of the electron beam is corrected on the basis of the calculated rotation deviation amount without providing No. 3.

Next, for future position correction, the first coordinate, the position shift amount of the first circuit pattern by the optical microscope image observation, the second coordinate, the second circuit pattern of the second circuit pattern by the optical microscope image observation. The positional deviation amount is stored and sent to the control unit 6.

Next, the circuit pattern formed on the sample 9 is observed by an optical microscope, and the positions of the chips having the circuit pattern, the distance between the chips, the repeating pitch of the repeating pattern such as a memory cell, and the like are previously determined. The measurement is performed and the measured value is input to the control unit 6. Further, a chip to be inspected and a region to be inspected in the chip are designated and input to the control unit 6. The image of the optical microscope can be observed at a comparatively low magnification, and when the surface of the sample 9 is covered with, for example, a silicon oxide film, the image can be observed through the base layer. The arrangement of chips and the layout of circuit patterns in the chips can be easily observed, and the area to be inspected can be easily set.

When the predetermined correction work by the optical microscope unit 4 and the preparatory work such as the inspection area setting are completed as described above, the sample 9 is moved under the electron optical system device 3 by the movement of the X stage 31 and the Y stage 32. Be moved to. When the sample 9 is placed under the electron optical system device 3, the same work as the correction work and the setting of the inspection area performed by the optical microscope unit 4 is performed by the electron beam image. Acquisition of an electron beam image at this time is performed by the following method.

On the basis of the coordinate values stored and corrected by the alignment based on the optical microscope image, the electron beam 19 is moved in the X and Y directions by the scanning deflector 15 in the same circuit pattern as that observed in the optical microscope section 4. It is scanned two-dimensionally. By the two-dimensional scanning of the electron beam, the secondary electrons 51 are generated from the observed region, and the second secondary electrons 5 generated on the reflecting plate 17 are generated.
2 is detected by the secondary electron detector 20, and an electron beam image is acquired. Since simple inspection position confirmation, position adjustment, and position adjustment have already been performed using the optical microscope image, and rotation correction has already been performed in advance, large adjustment is not necessary. The electron beam image has a higher resolution than the optical image and can perform alignment, position correction, and rotation correction with high magnification and high accuracy.

For the secondary electron detector 20, the conventional S
In the EM, a configuration including a scintillator (aluminum deposited phosphor), a light guide, and a photomultiplier tube is used. Since this type of detection device detects the light emission from the phosphor, it has poor frequency response and is not suitable for high-speed electron beam image formation. In order to solve this problem, as a detection device for detecting a high-frequency secondary electron signal,
Detection means using a semiconductor detector is disclosed in Japanese Patent Laid-Open No. 15545/1990.
Japanese Patent Laid-Open No. 5-258703 and Japanese Patent Laid-Open No. 5-258703, and a semiconductor detector is also used for high speed detection in the embodiment of the present invention.

Further, by the method of detecting secondary electrons using the secondary electron detector 20, digitizing the detected image signal immediately after detection, and then optically transmitting, the influence of noise generated in various conversions / transmissions. Can be reduced, and image signal data with a high SN ratio can be obtained. In the process of forming an electron beam image from the detected signal, the image processing unit 5 sets the desired pixel at the electron beam irradiation position designated by the control unit 6 to a desired pixel.
The detection signal corresponding to each corresponding time is used as the brightness gradation value according to the signal level and is stored in the first storage unit 46 or the second storage unit 4.
Sequentially store in 7. An electron beam image of the circuit pattern of the sample 9 is two-dimensionally formed by associating the electron beam irradiation position with the amount of secondary electrons associated with the detection time. It should be noted that in the present embodiment, the inspection method and apparatus for detecting the secondary electrons generated from the sample have been described, but backscattered electrons and reflected electrons are generated from the sample at the same time as the secondary electrons. These secondary charged particles as well as the secondary electrons can be similarly detected as an electron beam image signal.

When the image signal is transferred to the image processing section 5,
The electron beam image of the first area is stored in the first storage unit 46. The arithmetic unit 48 performs various image processes for aligning the stored image signal with the image signal of the other storage unit, standardizing the signal level, and removing noise signals.
Subsequently, the electron beam image of the second region is stored in the second storage unit 47, and the same circuit pattern of the electron beam image of the second region and that of the first electron beam image are stored while being subjected to the same arithmetic processing. And the image signals of the location are compared and calculated. Defect determination unit 49
Compares the absolute value of the difference image signal that has been compared and calculated by the calculation unit 48 with a predetermined threshold (inspection threshold), and if the difference image signal level is higher than the predetermined threshold (inspection threshold), the pixel is defective. The candidate is determined and the position, the number of defects, etc. are displayed on the monitor 50. Next, thirdly, the electron beam image of the region is stored in the first storage unit 46, and while being subjected to the same calculation, it is compared and calculated with the electron beam image of the second region previously stored in the second storage unit 47. The defect is judged. Thereafter, by repeating this operation, the image processing is executed for all the inspection areas.

With the above-described inspection method, a high-precision and high-quality electron beam image is acquired and comparative inspection is performed, so that a minute defect generated on a fine circuit pattern can be detected within an inspection time according to practicality. You can Further, by acquiring an image using an electron beam, patterns formed by a silicon oxide film or a resist film and foreign matter / defects of these materials, which cannot be inspected because light is transmitted by the optical pattern inspection method, are detected. Be able to inspect. Further, even when the material forming the circuit pattern is an insulator, the inspection can be stably performed.

When the sample 9 is irradiated with the electron beam 19,
The place becomes charged. In order to avoid the influence of the electrification at the time of inspection, the circuit pattern which irradiates the electron beam 19 in the pre-inspection preparatory work such as the above-mentioned position rotation correction or inspection region setting is selected in advance from the region to be inspected. Alternatively, it is preferable that the control unit 6 can automatically select an equivalent circuit pattern in a chip other than the chip to be inspected. As a result, the inspection image is not affected by the irradiation of the electron beam 19. The scanning with the high-current electron beam may be performed only once or may be repeated several times.

The inspection conditions of the apparatus using the electron beam as described above include the electron beam current, the number of times the image signal is added, the pixel size, the electron beam scanning direction, and the like. It is necessary to obtain optimum values of these parameters for each purpose of inspection, shape of circuit pattern, and material.

FIG. 2 shows a first embodiment of the present invention. FIG. 2 is a flowchart of the inspection procedure. First, sample 9
Is loaded into the sample chamber 8 (step 201). Next, the electron beam beam acceleration voltage setting (step 202), the electron beam beam current setting (step 203), the image signal addition number setting (step 204), the pixel size setting (step 205), and the electron beam beam scanning. Direction setting (Step 2)
06) is set. In this embodiment, as the inspection conditions, the current setting of the electron beam in step 203 is performed, and other parameters of the acceleration voltage of the electron beam, the number of additions of image signals, the pixel size, and the scanning direction of the electron beam are set. With regard to, since the standard value is used in consideration of the inspection purpose, inspection time, etc., the value is not changed.

In step 203, the current value of the electron beam is designated by the band, the current value is actually changed in that range, and the image of the sample 9 is acquired. These are done automatically.

FIG. 3 is an example of a screen when the current value of the electron beam is designated by band. On the screen 301, an electron beam acceleration voltage setting button 302, an electron beam current setting button 303, an image signal addition count setting button 304, a pixel size setting button 305, an electron beam scanning direction setting. Button 306 is displayed, and by clicking any of them with the mouse, a setting area is displayed below the screen 301. In this embodiment, the case where the electron beam current setting button 303 is clicked is shown. The electron beam current setting button 303 is displayed in order to distinguish it from other buttons that are clicked and not clicked. The frame is emphasized and color-coded. Below the screen 301, regions 307, 308, and 309 for designating the value of the electron beam in bands are displayed, and values are designated in each region. A return button 310 is provided below the screen 301, and when the return button 310 is clicked, a screen for executing an inspection (not shown) is displayed. The acceleration voltage of the electron beam, the number of times the image signal is added, the pixel size, and the condition setting of the scanning direction of the electron beam can also be changed within the range specified by the band, as in the case of setting the electron beam current. .

Returning to FIG. 2, after setting the above inspection conditions, the sample layout setting for determining the coordinates on the sample (Step 2
07), alignment for aligning the position on the sample to be irradiated with the electron beam (step 208), inspection area setting to set the area to be irradiated with the electron beam (step 209), setting of threshold value etc. (step 210), inspection (Step 211) is sequentially executed to automatically acquire the image of the sample 9. And
The acquired image is displayed on the monitor 50, and the operator determines the optimum current value of the electron beam from the image. If the image is still not suitable, steps 202-206
By changing the other conditions up to and acquiring images in the same manner, finally, the operator can determine the optimum inspection conditions.

As described above, according to the present embodiment, the inspection conditions can be easily set and the image can be acquired, so that the optimum inspection conditions can be derived in a short time and the working efficiency can be improved.

[0054]

As described above, according to the present invention, it is possible to provide an inspection apparatus using an electron beam, which can guide the optimum inspection conditions in a short time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the outline of the apparatus configuration of an SEM type appearance inspection apparatus.

FIG. 2 is a flowchart of an inspection procedure.

FIG. 3 is a screen for setting inspection conditions.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... SEM type visual inspection apparatus, 5 ... Image processing part, 9 ... Sample, 50 ... Monitor, 301 ... Screen, 302 ... Electron beam acceleration voltage setting button, 303 ... Electron beam current setting button, 304 ... button for setting number of addition of image signal, 305 button for setting pixel size, 306 button for setting scanning direction of electron beam.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Taku Ninomiya             882 Ichige, Ichima, Hitachinaka City, Ibaraki Prefecture             Ceremony company Hitachi High Technologies Design and manufacturing             Headquarters Naka Operations (72) Inventor Hiroshi Miyai             882 Ichige, Ichima, Hitachinaka City, Ibaraki Prefecture             Ceremony company Hitachi High Technologies Design and manufacturing             Headquarters Naka Operations F-term (reference) 4M106 AA01 AA02 BA02 CA39 DB05                       DE08

Claims (8)

[Claims] 1. An electron beam pattern inspection for detecting a secondary charged particle generated by irradiating a sample having a pattern with an electron beam to obtain an image and detecting a defect in the pattern of the sample using the image. The apparatus includes a monitor that displays conditions for irradiating the electron beam, the monitor displaying a reference value corresponding to each of a plurality of preset values of the electron beam, and the setting. Display a selection area for selecting one of the values from a predetermined range, and acquire the sample by irradiating the sample with the electron beam according to the set value other than the one value and the selected value. An electron beam type pattern inspection apparatus, which displays an area in which one of the set values is determined from the predetermined range based on the image. 2. An electron beam pattern inspection for detecting a secondary charged particle generated by irradiating a sample having a pattern with an electron beam to obtain an image, and detecting a defect in the pattern of the sample using the image. In the method, a plurality of setting values relating to the conditions when irradiating the electron beam is a reference value corresponding to each of the predetermined, and one of the setting values is selected from a predetermined range, The image is obtained by irradiating the sample with the electron beam according to the set value other than the one value and the selected value, and one of the set values is obtained based on the acquired image. A pattern inspection method using an electron beam, wherein the pattern inspection method is determined from the predetermined range. 3. A method for inspecting the pattern by irradiating a sample having a pattern formed on its surface with an electron beam to detect secondary electrons and reflected electrons generated from the sample, when setting inspection conditions. , The optical condition is controlled according to the purpose of inspection, the material and structure of the sample, the optical condition is specified by a band, and the image signal of the sample when the optical condition is changed within the range is acquired, and the target defect A pattern inspection method using an electron beam capable of obtaining the optimum optical condition that can obtain a sufficient contrast for detecting. 4. The purpose of inspection when setting the inspection conditions,
The accelerating voltage of the electron beam is controlled according to the material and structure of the sample, the accelerating voltage of the electron beam is specified by a band, and the image signal of the sample when changing within that range is acquired. The pattern inspecting method using an electron beam according to claim 3, wherein an optimum accelerating voltage of the electron beam that can obtain a sufficient contrast for detecting the defect is obtained. 5. When setting the inspection conditions, the purpose of the inspection,
The current of the electron beam is controlled according to the material and structure of the sample, the current of the electron beam is designated by a band, and the image signal of the sample when changed within that range is acquired and used as a target. 4. The pattern inspection method using an electron beam according to claim 3, wherein an optimum current of the electron beam that can obtain a sufficient contrast for detecting a defect is obtained. 6. The purpose of inspection when setting the inspection conditions,
The number of additions of the image signal is controlled according to the material and structure of the sample, the number of additions of the image signal is designated by a band, and the image signal of the sample when changed within that range is acquired and used. 4. The pattern inspection method using an electron beam according to claim 3, wherein an optimum number of times of addition of the image signals that can obtain a sufficient contrast for detecting a defect is obtained. 7. The purpose of inspection when setting the inspection conditions,
The pixel size of the image is controlled according to the material and structure of the sample, the pixel size of the image is designated by a band, and the image signal of the sample when the range is changed is acquired to detect the target defect. 4. The pattern inspection method using an electron beam according to claim 3, wherein the optimum pixel size of the previous period image that can obtain a sufficient contrast is obtained. 8. When setting the inspection conditions, the purpose of the inspection,
For controlling the scanning direction of the electron beam according to the material and structure of the sample, acquiring the image signal of the sample when the scanning direction of the electron beam is changed, and detecting the target defect. 4. A pattern inspection method using an electron beam according to claim 3, wherein an optimum scanning direction of the electron beam that can obtain a sufficient contrast is obtained.