JP3601382B2 - Inspection apparatus and inspection method using charged particle beam - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inspection apparatus and an inspection method for a semiconductor device such as a memory and an LSI having a fine circuit pattern and a circuit pattern such as a liquid crystal and a photomask, and particularly to an inspection apparatus and an inspection method using a charged particle beam.
[0002]
[Prior art]
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 on a photomask by lithography and etching. The quality of lithography, etching, and other processes in the manufacturing process of a semiconductor device, the generation of foreign matter in the manufacturing process, and the like greatly affect the yield of the semiconductor device. Therefore, in order to detect the occurrence of processing abnormality or defect early or in advance, it is necessary to inspect a pattern formed on a semiconductor wafer in a manufacturing process for each process.
[0003]
In the manufacturing process of a semiconductor device, the pattern is generated by scanning a pattern with a charged particle beam such as an electron beam or an optical visual inspection device for determining an abnormality using an image obtained by irradiating a pattern with a laser beam or the like. Various inspection devices for judging abnormalities from secondary electrons and reflected electrons using signal strength and images are actually used.
[0004]
As an example of an optical inspection apparatus for inspecting a defect existing in a pattern on a semiconductor wafer, a defect inspection apparatus that irradiates a semiconductor wafer with white light and compares the same circuit patterns of a plurality of LSIs using an optical image is known. This is known, and its summary is described in the magazine "Semiconductor World of the Month", August 1995, pp. 96-99.
[0005]
When a semiconductor wafer in a manufacturing process is inspected by such an optical inspection method, 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 cannot be detected. In addition, it was not possible to detect an unetched residue or a non-opening defect in a minute conduction hole, which was lower than the resolution of the optical system. Furthermore, a defect generated at the bottom of the step of the wiring pattern could not be detected.
[0006]
As described above, with the miniaturization of circuit patterns, the complexity of circuit pattern shapes, and the diversification of materials, it has become difficult to detect defects using optical images.Therefore, charged particle beams with higher resolution than optical images, especially electron There has been proposed a method of comparing and inspecting a circuit pattern using an image obtained by scanning a line. When a circuit pattern is compared and inspected using an electron beam image, an image is acquired at a very high speed compared with observation by a scanning electron microscope (SEM) in order to obtain a practical inspection time. There is a need. Then, it is necessary to ensure the resolution of the image acquired at high speed and the SN ratio of the image.
[0007]
As an example of such a pattern comparison inspection apparatus using an electron beam, a document "Journal of Vacuum Science Technology B, Vol. 9, No. 6, pp. 3005 to 3009 (1991)" (J. Vac. Sci. Tech. B, Vol. 9, No. 6, pp. 3005-3009 (1991)), and the document "Journal of Vacuum Science Technology B, Vol. 10, No. 6, Pages 2804 to 2808 (1992) "(J. Vac. Sci. Tech. B, Vol. 10, No. 6, pp. 2804-2808 (1992)), and JP-A-5-258703. And US Pat. No. 5,502,306 disclose an electron beam having an electron beam current 100 times or more (10 nA or more) that of a normal SEM. Is irradiated on a conductive substrate (such as an X-ray mask), and any or a plurality of generated secondary electrons, reflected electrons, and transmitted electrons are detected, and images formed from the signals are compared and inspected to automatically detect defects. A detection method is described.
[0008]
In addition, it is difficult to obtain a high-resolution image due to the space charge effect with a high current and low acceleration electron beam. As a method for solving this problem, Japanese Patent Application Laid-Open No. 5-258703 mentioned above discloses a method of immediately before the sample. Describes a method of decelerating a high-acceleration electron beam and irradiating the sample with a substantially low-acceleration electron beam on a sample.
[0009]
As a method for acquiring an electron beam image at a high speed, a method of continuously irradiating a semiconductor wafer on a sample stage with an electron beam while continuously moving the sample stage is disclosed in JP-A-59-160948 and JP-A-5-160948. -258703.
[0010]
In such an inspection apparatus that irradiates a sample substrate with a finely focused electron beam at a high speed to acquire and inspect an electron beam image, an aberration generated in comparison with the amount of deflection of the electron beam, that is, an acquisition having deflection distortion. Comparing an image with a reference image having no deflection distortion or an acquired image having a deflection distortion different from the previous deflection distortion will result in an erroneous result that there is a defect in a part that is not originally a defect.
[0011]
Regarding this deflection distortion, Japanese Patent Application Laid-Open No. Sho 58-154153 discloses that the stage obtained is moved to a position with respect to the optical axis of the visual field moved by the deflection of the charged particle beam, and the acquired image is degraded by the off-axis deflection. It is stated to prevent. However, when scanning the charged particle beam while continuously moving the sample stage, it is necessary to determine the deflection scanning region of the charged particle beam in consideration of the rotation error of the sample, and there is no description on this point.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to reduce the influence of deflection distortion of an image signal of a sample obtained by scanning a charged particle beam while moving or stopping the sample stage, and to provide a charged particle beam that can obtain a defect of the sample. An object of the present invention is to provide an inspection apparatus and an inspection method used.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is to match the optical axis of the charged particle beam with the center of the target area on the sample to be irradiated with the charged particle beam, and to perform the irradiation of the charged particle beam based on the moving speed of the stage. A scanning direction is determined, and then, the sample is irradiated with the charged particle beam while one of the stages is stopped and the other is moved.
[0014]
The present invention also provides an inspection apparatus for extracting a defect by comparing an image of a first region and an image of a second region obtained by scanning with a charged particle beam, wherein the first or the second region When scanning with a charged particle beam a spatially continuous image acquisition region including at least one of the regions, the center of at least one axis in a rectangular coordinate system centered on the optical axis of the charged particle beam is image acquisition. It is provided with a configuration for scanning a charged particle beam so as to pass near the center of the region.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
(Example)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
An outline of a configuration of an SEM type visual inspection apparatus for inspecting a pattern of a semiconductor wafer or a mask or a reticle using an electron beam to which the present invention is applied will be described. FIG. 1 is a longitudinal sectional view schematically showing the configuration of the SEM appearance inspection apparatus. The SEM appearance inspection apparatus 1 is roughly divided into an inspection room 2 including an electron optical system system 3, an optical microscope unit 4, and a sample room 8, an image processing unit 5, a control unit 6, and a secondary electron detection unit. 7
[0017]
The electron optical system 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, an objective lens 16, a reflection plate 17, and an ExB deflector 18. The sample 9 is irradiated with an electron beam 19 generated by the electron gun 10 and extracted by the extraction electrode 11 through the condenser lens 12, the aperture 14, and the objective lens 16. The electron beam 19 is a narrowed beam, and the sample 9 is scanned by the scanning deflector 15, and reflected electrons and secondary electrons 51 are generated from the sample 9. The secondary electrons have their trajectories bent by the ExB deflector 18 and irradiate the reflecting plate 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 opening of the stop 14 by the blanking deflector 13, the irradiation of the sample 9 with the electron beam 19 can be prevented.
[0018]
The sample chamber 8 includes a sample stage 30, an X stage 31, 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 a position near the electron optical system 3 in the room of the inspection room 2 so as not to affect each other, and is provided between the electron optical system 3 and the optical microscope unit 4. Is known. The X stage 31 or the Y stage 32 reciprocates a known distance between the electron optical system 3 and the optical microscope unit 4.
[0019]
The optical microscope unit 4 includes a white light source 40, an optical lens 41, and a CCD camera 42. Although not shown, an acquired image is sent to the image processing unit 5 in the same manner as an electron beam image described later.
[0020]
In this embodiment, a length measuring device based on laser interference is used as the position monitor measuring device 34. The positions of the X stage 31, the Y stage 32, and the rotating stage 33 can be monitored in real time, and the position information can be sent to the control unit 6. Although not shown, data such as the number of rotations of the motors of the X stage 31, the Y stage 32, and the rotation stage 33 are also transmitted from the respective drivers to the controller 6. The control unit 6 can accurately grasp the region and position where the electron beam 19 is irradiated based on these data, and corrects the positional deviation of the irradiation position of the electron beam 19 in real time as necessary. The correction can be performed using the control circuit 43. Further, even if the sample 9 is changed, the region irradiated with the electron beam can be stored for each sample.
[0021]
As the sample height measuring device 35, an optical measuring device using a measuring method other than the electron beam, for example, a laser interferometer or a reflected light measuring device for measuring a change in the position of reflected light is used. The configuration is such that the height of the sample 9 mounted on the Y stage 31 can be measured in real time. In the present embodiment, a method in which an elongated white light passing through a slit is applied to a sample 9 through a transparent window, the position of reflected light is detected by a position detection monitor, and a height change amount is calculated from a position change. Was used. Based on the measurement data of the sample height measuring device 35, the focal length of the objective lens 16 for narrowing down the electron beam 19 is dynamically corrected so that the electron beam 19 can be always focused on the inspection area. It has become. Further, it is also possible to configure so that the warpage and the height distortion of the sample 9 are measured in advance before the electron beam irradiation, and the correction conditions for each inspection area of the objective lens 16 are set based on the data. .
[0022]
In order to obtain an image of the sample 9, the electron beam 19 narrowed down is irradiated on the sample 9 to generate secondary electrons 51, which are scanned by the electron beam 19 and moved by the X stage 31 and the Y stage 32. Synchronously detect.
[0023]
The electron beam 19 is extracted from the electron gun 10 by applying a voltage between the electron gun 10 and the extraction electrode 11. The electron beam 19 is accelerated by applying a high negative voltage to the electron gun 10. As a result, the electron beam 19 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 and the Y stage 32 on the sample stage 30. The sample 9 mounted on the rotating stage 33 is irradiated.
[0024]
A scanning signal and a scanning signal generator 44 for generating a blanking signal are connected to the blanking deflector 13, and an objective lens power supply 45 is connected to the objective lens 16. A negative voltage can be applied to the sample 9 by the retarding power supply 36. By adjusting the voltage of the retarding power supply 36, the primary electron beam can be decelerated, and the irradiation energy of the electron beam 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 electron beam 19 is deflected by the blanking deflector 13, and the electron beam 19 can be controlled so as not to pass through the aperture 14.
[0025]
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. Above the sample 9, an ExB (E-cross-B) deflector 18 is arranged, and the accelerated secondary electrons 51 are deflected in a predetermined direction. The amount of deflection 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 changed in conjunction with a negative voltage applied to the sample. The secondary electrons 51 deflected by the ExB deflector 18 collide with the reflector 17 under predetermined conditions. The reflection plate 17 has a conical shape, and the electron beam 19 passes through an opening provided at the center thereof. When the accelerated secondary electrons 51 collide with the reflector 17, a second secondary electron 52 having an energy of several V to 50 eV is generated from the reflector 17.
[0026]
The secondary electron detector 20 is disposed above the objective lens 16 in the inspection room 2 and detects the second secondary electrons 52. The output signal of the secondary electron detector 20 is provided outside the inspection room 2. The amplified data is amplified by the preamplifier 21, converted into digital data by the AD converter 22, and transmitted from the light conversion unit 23 to the electric conversion unit 25 of the image processing unit 5 by the light transmission unit 24. When the reflection plate 17 is not provided, the secondary electrons 51 may be detected by the secondary electron detector 20 instead of the second secondary electrons 52.
[0027]
The high-voltage power supply 26 supplies a preamplifier drive power supply 27 for driving the preamplifier 21, an AD converter drive power supply for driving the AD converter 22, and a voltage to be applied to the secondary electron detector 20 to attract the second secondary electrons. Power is supplied to the reverse bias power supply 29. The second secondary electrons 52 generated by colliding with the reflection plate 17 are guided to the secondary electron detector 20 by an attraction electric field generated by the secondary electron detector 20 by the supply of the reverse bias power supply 29.
[0028]
The secondary electron detector 20 detects the secondary electrons 51 generated during the irradiation of the sample 9 with the electron beam 19 and then accelerates and collides with the reflector 17 to generate the second secondary electrons.
52 is configured to be detected in conjunction with the scanning timing of the electron beam 19.
[0029]
The output signal of the secondary electron detector 20 is amplified by a preamplifier 21 installed outside the inspection room 2, and converted into digital data by an AD converter 22. The AD converter 22 is configured to convert an 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. As described above, since the detected analog signal is digitized and transmitted immediately after the detection, a signal having a high speed and a high SN ratio can be obtained.
[0030]
The sample 9 is mounted on the X stage 31 and the Y stage 32. The X stage 31 and the Y stage 32 are stationary when the inspection is performed, and the electron beam 19 is two-dimensionally scanned when the inspection is performed. , Y stage 32 is continuously moved in the Y direction at a constant speed, and any one of methods of linearly scanning electron beam 19 in the X direction can be selected. The former method is effective for inspecting a specific relatively small area, and the latter method is effective for inspecting a relatively large area.
[0031]
The image processing unit 5 includes a first storage unit 46, a second storage unit 47, a calculation unit 48, a defect determination unit 49, and a monitor 50. The captured electron beam image or optical image is displayed on the monitor 50. Operation commands and operation conditions of each unit of the device are input and output from the control unit 6. In the control unit 6, conditions such as acceleration voltage at the time of electron beam generation, electron beam deflection width, deflection speed, signal fetch timing of the secondary electron detector 20, and moving speed of the sample stage 30 are arbitrarily set according to the purpose. Is entered so that it can be selected or set. The control unit 6 monitors the position and height deviations from the signals of the position monitor length measuring device 34 and the sample height measuring device 35 using the correction control circuit 43, 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.
[0032]
The image processing unit 5 includes a first storage unit 46 and a second storage unit 47, a calculation unit 48, a defect determination unit
49, and a monitor 50. The image signal of the sample 9 transmitted by the optical fiber 24 is stored in the first storage unit 46 or the second storage unit 47 after being converted into an electric signal again by the electric conversion unit 25.
[0033]
The arithmetic unit 48 performs positioning of the stored image signal with the image signal of the other storage unit, normalizes the signal level, performs various image processing for removing noise signals, and compares the two image signals. Calculate.
[0034]
The defect judging unit 49 compares the absolute value of the difference image signal calculated by the operation unit 48 with a predetermined threshold value. If the difference image signal level is higher than the predetermined threshold value, the pixel is determined to be defective. The position is determined as a candidate, and the number of defects is displayed on the monitor 50.
[0035]
In the above-described embodiment, the secondary electron detector 20 is applied with the reverse bias voltage from the reverse bias power supply 29. However, the secondary electron detector 20 may be configured not to apply the reverse bias voltage. In the present embodiment, a PIN type semiconductor detector is used as the secondary electron detector 20, but another type of semiconductor detector, for example, a Schottky type semiconductor detector or an avalanche type semiconductor detector may be used. . If conditions such as responsiveness and sensitivity are satisfied, an MCP (micro channel plate) can be used as a detector.
[0036]
Next, a case where a semiconductor wafer subjected to pattern processing in a manufacturing process is inspected by the SEM appearance inspection apparatus 1 shown in FIG. 1 will be described with reference to FIG.
[0037]
The sample 9 is loaded into a sample exchange chamber (not shown). After the sample 9 is mounted on a sample holder (not shown) and held and fixed, the sample exchange chamber is evacuated, and 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 rotating stage 33 and held and fixed.
[0038]
The sample 9 is arranged at predetermined first coordinates 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 predetermined inspection conditions registered in advance. As a result, an optical microscope image of the circuit pattern formed on the sample 9 is observed. Then, it is compared with an equivalent circuit pattern image stored in advance for position rotation correction, and a position correction value of the first coordinate is calculated. Next, it moves away from the first coordinates by a certain distance, moves to the second coordinates where a circuit pattern equivalent to the first coordinates exists, and similarly observes the optical microscope image and stores it for position rotation correction. The position correction value of the second coordinate and the amount of rotation deviation with respect to the first coordinate are calculated by comparison with the circuit pattern image. The rotation stage 33 is rotated by the calculated rotation deviation amount to correct the rotation.
[0039]
In the present embodiment, the amount of rotation deviation is corrected by the rotation of the rotation stage 33. However, a method of correcting the scanning deflection position of the electron beam based on the calculated amount of rotation deviation without providing the rotation stage 33 is also possible. The amount of rotation deviation can be corrected. This method will be described later.
[0040]
Next, for future position correction, the first coordinate, the amount of displacement of the first circuit pattern by observing the optical microscope image, the second coordinate, the amount of misalignment of the second circuit pattern by observing the optical microscope image. Is stored and sent to the control unit 6.
[0041]
Next, the circuit pattern formed on the sample 9 is observed by an optical microscope, and the position of the chip where the circuit pattern is located, the distance between the chips, or the repetition pitch of a repetition pattern such as a memory cell is measured in advance. 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 relatively low magnification, and when the surface of the sample 9 is covered with, for example, a silicon oxide film, the image can be transmitted down to the base and observed. In addition, the arrangement of the chips and the layout of the circuit patterns in the chips can be easily observed, and the region to be inspected can be easily set.
[0042]
When the preparatory work such as the predetermined correction work and the setting of the inspection area by the optical microscope unit 4 is completed as described above, the sample 9 is moved below the electron optical system 3 by the movement of the X stage 31 and the Y stage 32. You. When the sample 9 is placed below the electron optical system 3, the same operation as the correction operation and the setting of the inspection area performed by the optical microscope unit 4 is performed by an electron beam image. The acquisition of the electron beam image at this time is performed by the following method.
[0043]
Based on the coordinate values stored and corrected by the alignment based on the optical microscope image, the electron beam 19 is two-dimensionally scanned in the X and Y directions by the scanning deflector 15 in the same circuit pattern as that observed by the optical microscope unit 4. Is scanned. Due to the two-dimensional scanning of the electron beam, secondary electrons 51 are generated from the observed part, and the second secondary electrons 52 generated by the reflection plate 17 are detected by the secondary electron detector 20 to obtain an electron beam image. Is done. Since simple inspection position confirmation, position alignment, and position adjustment have already been performed using an optical microscope image, and rotation correction has been performed in advance, large adjustment is not required. 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.
[0044]
Regarding the secondary electron detector 20, in the conventional SEM, a configuration using a scintillator (a phosphor deposited on aluminum), a light guide, and a photomultiplier tube is used. Since this type of detection device detects light emitted by a phosphor, it has poor frequency response and is unsuitable for high-speed electron beam image formation. In order to solve this problem, as a detecting device for detecting a high-frequency secondary electron signal, a detecting means using a semiconductor detector is described in JP-A-2-15545 and JP-A-5-258703. Thus, the embodiment of the present invention also uses a semiconductor detector for high-speed detection.
[0045]
In addition, the method of detecting secondary electrons using the secondary electron detector 20, digitizing the detected image signal immediately after detection, and then transmitting the light, reduces the effect of noise generated in various conversions and transmissions. , Image signal data having a high SN ratio. In the process of forming an electron beam image from the detected signal, the image processing unit 5 applies a detection signal every time corresponding to a desired pixel at the electron beam irradiation position designated by the control unit 6 according to the signal level. The stored brightness gradation values are sequentially stored in the first storage unit 46 or the second storage unit 47. By correlating the electron beam irradiation position with the amount of secondary electrons associated with the detection time, an electron beam image of the circuit pattern of the sample 9 is formed two-dimensionally. In this embodiment, the inspection method and apparatus for detecting secondary electrons generated from the sample have been described. However, backscattered electrons and reflected electrons are generated from the sample simultaneously with the secondary electrons. These secondary charged particles as well as secondary electrons can be similarly detected as electron beam image signals.
[0046]
When the image signal is transferred to the image processing unit 5, the electron beam image of the first area is stored in the first storage unit. The arithmetic unit 48 performs alignment of the stored image signal with the image signal of the other storage unit, normalization of a signal level, and various image processing for removing a noise signal. 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 the first electron beam image is obtained while performing the same arithmetic processing. And the image signal at the location are compared. The defect judging unit 49 compares the absolute value of the difference image signal calculated by the operation unit 48 with a predetermined threshold value. If the difference image signal level is higher than the predetermined threshold value, the pixel is determined to be defective. The position is determined as a candidate, and the number of defects is displayed on the monitor 50. Next, thirdly, the electron beam image of the region is stored in the first storage unit 46, and is compared with the electron beam image of the second region previously stored in the second storage unit 47 while performing the same operation. Is determined. Thereafter, by repeating this operation, image processing is performed on all inspection areas.
[0047]
By acquiring a high-precision and high-quality electron beam image by the above-described inspection method and performing comparative inspection, a minute defect generated on a fine circuit pattern can be detected in an inspection time conforming to practicality. In addition, by acquiring an image using an electron beam, light transmitted by the optical pattern inspection method cannot be inspected, and a pattern formed by a silicon oxide film or a resist film, and foreign materials and defects of these materials can be removed. Be able to inspect. Further, the inspection can be stably performed even when the material forming the circuit pattern is an insulator.
[0048]
When the sample 9 is irradiated with the electron beam 19, the portion is charged. In order to avoid the influence of the electrification at the time of the inspection, the circuit pattern to be irradiated with the electron beam 19 in the pre-inspection preparation work such as the position rotation correction or the inspection area setting is selected from circuit patterns existing outside the inspection area in advance. Alternatively, it is preferable that the controller 6 can automatically select an equivalent circuit pattern on a chip other than the chip to be inspected. Thus, the influence of the irradiation of the electron beam 19 does not affect the inspection image. The scanning with the large current electron beam may be performed only once or may be repeated several times.
[0049]
The conditions for irradiating the sample with the electron beam include the irradiation amount of the electron beam per unit area, the current value of the electron beam, the scanning speed of the electron beam, and the irradiation energy of the electron beam irradiating the sample. For these parameters, it is necessary to find the optimum values for each of the shapes and materials of the circuit patterns. For that purpose, it is necessary to freely adjust and control the irradiation energy of the electron beam irradiating the sample. In this embodiment, a retarding power supply
A negative voltage for decelerating the primary electrons of the electron beam 19 is applied by 36, and by adjusting this voltage, the irradiation energy of the electron beam 19 can be appropriately adjusted. When the acceleration voltage applied to the electron gun 10 is changed, a change in the axis of the electron beam 19 occurs and various adjustments are required. In this embodiment, the acceleration voltage applied to the electron gun 10 is not changed. Thus, the irradiation energy of the electron beam 19 can be adjusted.
[0050]
2 to 4 and FIGS. 10 and 11 show a first embodiment of the present invention. 2 and 3 are views for explaining the scanning direction of the electron beam, and are enlarged views of a portion of the sample irradiated with the electron beam, and FIG. 4 is a view for explaining the scanning deflection direction of the electron beam corresponding to FIG. It is a schematic diagram. FIG. 10 is a flowchart showing the procedure of the inspection in FIG. 2, and FIG. 11 is a flowchart showing the procedure of the inspection in FIG.
[0051]
As shown in FIG. 2, when inspecting a certain relatively small inspection area, an image is formed by two-dimensionally scanning the electron beam 19 while the stage is stationary.
[0052]
At the time of scanning, the sample 9 is irradiated with the electron beam 19 in only one direction shown by a solid line, and blanked during the reversal of the electron beam 19 shown by a dashed line.
The sample 19 is not irradiated, and the sample 9 is uniformly and spatially and temporally irradiated with the electron beam 19.
[0053]
This is a case where the electron beam 19 is sequentially scanned from the end in a rectangular area having a width w and a length 1 which is the image acquisition area 60. First, in step 61 of FIG. 10, the angle between the scanning direction of the electron beam 19 and the X-axis direction, that is, the wafer rotation angle θ is detected. Details will be described with reference to FIG. Next, in step 62, the position of the sample 9 is corrected by the rotating stage 33 so that the scanning direction of the electron beam 19 and the X-axis direction match. Next, in step 63, the image acquisition area 60 is set, and in step 64, the center of the image acquisition area 60 is set.
The X stage 31 and the Y stage 32 are stopped by a command from the control unit 6 so that 53 becomes the center of the two-dimensional scanning by the electron beam 19. That is, the sample is stopped so that the optical axis of the electron optical system 3 coincides with the center of the image acquisition area 60, and then an electron beam is scanned to acquire an image.
[0054]
In FIG. 2, the width of the image acquisition area 60 is defined as w, the length is defined as l, and the position of the optical axis and the center 53 of the image acquisition area 60 are coordinate origins (0, 0) under an orthogonal XY coordinate system. 0), the electron beam 19 is deflected by the scanning deflector 15 so that the scanning start point is at the coordinate (-w / 2, l / 2) at the point A at the upper left corner of the image acquisition area 60, and is moved in the X direction. Along the scanning range w from the left end to the right end B of the area. This scanning in the X direction is repeated while shifting one scanning at a time at a pitch 59 (Δp) set in the Y direction, and scanning is performed up to the coordinates (w / 2, −1/2) at the lower right corner. These scanning conditions are set in advance, and are designated by the control unit 6. The above scanning is the step of FIG.
Steps 65 to 69 are performed.
[0055]
When scanning along the image acquisition area 60 is performed by such a scanning method, the amount of deflection distortion is distributed at the scanning center, so that the total amount of deflection in the scan of the image acquisition area 60 is minimized, and the deflection per pixel is reduced. The distortion is minimized, and it is possible to prevent a defect from being erroneously detected in the comparison inspection of the two images.
[0056]
The method shown in FIGS. 3 and 4 is an application of the above method when scanning an electron beam while moving the stage.
[0057]
The semiconductor wafer that is the sample 9 has a diameter of 150 mm to 200 mm, while the width w that can be scanned by the electron beam 19 using a scanning electron microscope (SEM) is at most about several hundred μm. According to the above method, when inspecting all over, it takes time to scan the electron beam while stopping the stage for each image acquisition area, and it takes time to move the stage, and it takes a long time to inspect one semiconductor wafer. Is not suitable. Therefore, a method of shortening the inspection time by scanning the electron beam 19 in one direction at a high speed in a direction orthogonal to or intersecting with the stage movement direction while continuously moving the stage in one direction at a constant speed can be considered. . White arrows indicate stage speed v.
[0058]
In FIG. 3, first, in step 71 of FIG. 11, the angle between the scanning direction of the electron beam 19 and the X-axis direction, that is, the wafer rotation angle θ is detected. The wafer rotation angle θ will be described in detail with reference to FIG. Next, in step 72, the position of the sample 9 is corrected by the rotating stage 33 so that the scanning direction of the electron beam 19 coincides with the X-axis direction. Then, step
At 73, the image acquisition area 60 is set, and at step 74, when the Y stage 32 moves in the Y direction according to an instruction from the control unit 6, the optical axis 54 of the electron beam 19 moves to the center of the image acquisition area 60. The X stage is stopped so as to pass through 53, and the electron beam 19 is scanned by the scanning deflector 44 while the Y stage 32 continuously moves at a constant speed in the Y direction.
[0059]
The scanning of the electron beam 19 viewed from the optical axis of the electron optical system 3 is as shown in FIG. When scanning the image acquisition while continuously moving the sample 9 by the stage mechanism, it is necessary to consider the constant speed of the stage movement in the stage movement direction. Assuming that the width of the image acquisition region 60 is w, the stage speed v scans the sample 9 moving at a constant speed in the Y direction with the electron beam 19 horizontally in the X direction. It is necessary to scan the electron beam 19 with the scanning deflector 15 at a tracking angle δ and a scanning width | w / cos δ | Since the stage speed v slightly changes over time, the optical axis 54 of the electron beam 19 may be shifted in the stage moving direction at the center 53 of the image acquisition area 60 accordingly. The following angle δ is determined by the stage speed v of the Y stage 32 and the scanning speed u of the electron beam. That is, δ = arcsin (v / u). Here, the sign of δ, v, u is positive in the direction of the arrow in FIGS. 3 and 4. The following angle δ may be assumed to be zero if the stage speed v is sufficiently smaller than the scanning speed u.
[0060]
The following calculation of the following angle δ is performed in step 75 of FIG. 11, and scanning is performed in steps 76 to 81.
[0061]
Scanning of the image acquisition area 60 at the set pitch 59 (Δp) is performed by repeating scanning at a time interval Δp / v. These scanning conditions are set in advance and specified by the control unit 6.
[0062]
In the area or position where the electron beam 19 is irradiated, the measurement data measured by the position monitor length measuring device 34 installed on the X stage 31 and the Y stage 32 is transferred to the control unit 6 every moment. Is understood in detail. Similarly, the fluctuation of the height of the region irradiated with the electron beam 19 or the position is described in detail by transferring the measurement data measured by the sample height measuring device 35 to the control unit 6 every moment. To be grasped. Based on these data, the deviation of the irradiation position or the focal position of the electron beam 19 is calculated, and these corrections are automatically corrected by the correction control circuit 43. In this way, the electron beam 19 is controlled with high accuracy and precision.
[0063]
By the above-described scanning method, scanning along the image acquisition area is performed, and the deflection distortion amount is distributed at the scanning center, so that the total deflection amount in scanning the image acquisition area is minimized, and the deflection distortion per pixel is minimized. In addition, it is possible to prevent erroneous determination of a defect in inspection by comparing two images.
[0064]
5 to 7 show a second embodiment of the present invention. 5 and 6 are views for explaining the scanning direction of the electron beam, as in FIG. 2, and are enlarged views of a portion of the sample irradiated with the electron beam. FIG. 7 is a drawing corresponding to FIG. It is a schematic diagram explaining a deflection direction.
[0065]
The difference between the present embodiment and the first embodiment is that the rotary stage 33 is not provided. The other configuration is the same as that of the first embodiment, and will not be described here.
[0066]
As shown in FIG. 5, since the image of the sample 9 does not have the rotating stage 33, it is assumed that the image is rotated by an angle θ with respect to the XY axis.
[0067]
First, similarly to the first embodiment, a position correction value of predetermined first coordinates and a second coordinate, and an amount of rotational displacement of the second coordinates with respect to the first coordinates are calculated from an optical microscope image or an electron beam image. Is done. A description will be given of a scanning method for correcting the rotational deviation amount by correcting the scanning deflection position of the electron beam and forming an image in which the deflection distortion amount per pixel is minimized.
[0068]
When performing a specific relatively small area inspection, an image is formed by two-dimensionally scanning an electron beam while the stage is stationary. FIG. 5 shows a two-dimensional scanning method in the case where the wafer has the angle θ of the rotational shift amount. The image acquisition area is designated by the control unit 6.
The stage is stopped so that the center 53 of the 60 coincides with the center of the two-dimensional scanning, that is, the optical axis 54. In this case, the center of the two-dimensional scanning is located at a position that is a half of the width w of the image acquisition area 60 and a half of the length l. That is, the electronic optical system 3 is stopped so that the optical axis 54 of the electron optical system 3 and the center 53 of the image acquisition area 60 coincide.
[0069]
In FIG. 5, if the width of the image acquisition area 60 is w and the height is 1 and the center 53 of the image acquisition area 60 is the origin (0, 0) of the coordinates under an orthogonal XY coordinate system, The electron beam 19 is scanned and deflected so that the scanning start point A is at the coordinates (− (w / 2) cos θ + (l / 2) sin θ, (w / 2) sin θ + (l / 2) cos θ) of the image acquisition area 60. It is deflected by the detector 15 and scans to the end B at an angle θ along the area. Scanning in this direction is repeated while being shifted by one scan at a preset scanning pitch 59 (Δp), and the coordinates ((w / 2) cos θ− (l / 2) sin θ, − (w / 2) sin θ− (l / 2) Scan to cos θ).
[0070]
During scanning, the sample 9 is irradiated with the electron beam 19 in only one direction indicated by a solid line, and blanking is performed so that the electron beam 19 is not irradiated on the sample 9 during the reversal of the electron beam 19 indicated by a broken line. The electron beam can be uniformly and spatially and temporally irradiated on the sample 9. Blanking is performed by deflecting the electron beam 19 by the blanking deflector 13 so as not to pass through the aperture 14.
[0071]
According to the above-described scanning method, scanning along the image acquisition area is performed, and the amount of deflection distortion is distributed at the scanning center, so that the total amount of deflection in the scanning of the image acquisition area is minimized, and the deflection distortion per pixel is minimized. An image suitable for inspection is formed.
[0072]
When inspecting a wide area, according to the above-described method, acceleration, deceleration, and position setting are added for each image acquisition area in addition to the time for stopping the stage and scanning the electron beam as the movement time of the stage. It takes time, and it takes a long time for the entire inspection time. Therefore, when inspecting a wide area, the electron beam is scanned in one direction at high speed in a direction orthogonal to or crossing the stage movement direction while moving the stage continuously in one direction at a constant speed, thereby obtaining an inspection area. An inspection method that acquires an image may be used. The electron beam acquisition time for one scanning width of the predetermined distance is only the time for the stage to move the predetermined distance.
[0073]
FIGS. 6 and 7 illustrate the case of the single-axis continuous movement of the stage, and FIGS. 8 and 9 illustrate the case of the two-axis continuous movement of the stage.
[0074]
First, the third embodiment of the present invention in the case of continuous movement of one axis of the stage will be described below. In FIG. 6, when one axis of the stage continuously moves at an angle θ of the rotational deviation amount, when the Y stage 32 is moved in the Y direction at a constant stage speed v by the designation from the control unit 6 shown in FIG. Then, the X stage 31 is stopped so that the optical axis 54 of the electron optical system 3 passes through the center 53 of the image acquisition area 60. Then, while the Y stage 32 is continuously moving in the Y direction, the electron beam 19 is scanned along a rectangular area having a width w and a length l.
[0075]
While the Y stage 32 is moving, the electron beam 19 repeats scanning around the center 53 of the image acquisition area 60. At this time, the scanning pattern viewed from the optical axis 54 of the electron optical system 3 is as follows. As shown in FIG. 7, in the XY coordinate system having the optical axis 54 as the origin, the width of the image acquisition area 60 is w, the length is 1, the scanning speed is u, and the apparent scanning speed from the sample 9 is u ′. Then, the following angle δ includes the rotational deviation θ, and δ = arcsin ((u ′ / u) sin θ−v / u). Here, δ, u ′, u, θ, and v each have the positive direction of the arrow in FIG.
[0076]
Assuming that the optical axis 54 is the origin (0, 0) under the orthogonal XY coordinates, the scanning start point A is such that the scanning center is the coordinate ((l / 2) cos θ, 0) and the scanning width is ( (cos θ / cos δ) The scanning is performed up to the point B with the following angle δ so that w. However, when scanning the image acquisition while the sample is continuously moved by the stage mechanism, it is necessary to consider the constant speed of the stage movement in the direction of the stage movement.
[0077]
Then, using the scanning pitch 59 (Δp) on the sample 9 shown in FIG. 6, the coordinates of the scanning center are moved by Δp · cos θ at every time interval (Δp · sin θ) / v, Is repeated until (-(l / 2) cos θ, 0), so that the image acquisition area 60 can be scanned at a preset scanning pitch 59 (Δp). These scanning conditions are set in the inspection apparatus in advance, and designated by the control unit 6 shown in FIG. Since the stage speed v slightly changes with time, the optical axis 54 of the electron beam 19 may be shifted in the stage moving direction at the center 53 of the image acquisition area 60 accordingly.
[0078]
In scanning the image acquisition area 60, the sample 9 is irradiated with the electron beam 19 only in one direction indicated by a solid line in the embodiments of FIGS. During the swingback of the electron beam 19 indicated by the broken line, the sample 9 is blanked so that the electron beam 19 is not irradiated, so that the sample 9 is uniformly and spatially and temporally irradiated with the electron beam 19. Can be. Blanking is performed by deflecting the electron beam 19 by the blanking deflector 13 so as not to pass through the aperture 14.
[0079]
The region or position where the electron beam is irradiated is grasped in detail by transferring the measurement data of the position monitor length measuring device 34 installed on the X stage 31 and the Y stage 32 to the control unit 6 every moment. You. Similarly, the fluctuation of the height of the region or position irradiated with the electron beam 19 can be grasped in detail by transferring the measurement data of the sample height measuring device 35 to the control unit 6 every moment. Based on these data, the deviation of the irradiation position or the focal position of the electron beam 19 is calculated, and these corrections are automatically corrected by the correction control circuit 43. In this way, the electron beam can be scanned with high accuracy and precision.
[0080]
According to the above, scanning along the image acquisition area is performed, and the deflection distortion amount is distributed at the scanning center. Therefore, the total deflection amount in the scanning of the image acquisition area is minimized, and the deflection distortion per pixel is minimized. Erroneous determination of a defect in inspection by image comparison can be prevented.
[0081]
Next, a description will be given of a fourth embodiment of the present invention in the case of continuous movement of the stage in two axes. FIG. 8 is a view for explaining the scanning direction of the electron beam similarly to FIG. 2, and is an enlarged view of a portion of the sample irradiated with the electron beam. FIG. 9 shows the scanning deflection direction of the electron beam corresponding to FIG. It is a schematic diagram explaining.
[0082]
First, a description will be given of a scanning method when the two axes of the stage continuously move at the rotation deviation angle θ.
[0083]
In FIG. 8, first, the X stage 31 and the Y stage 32 are moved to the stage speed v so that the center 53 of the rectangular image acquisition area 60 having the width w and the length l coincides with the optical axis 54 of the scanning of the electron beam 19. To move at a constant speed. Next, the electron beam 19 is scanned while moving the stage. At this time, the stage speed v, which is the combined speed of both the X stage 31 and the Y stage 32 shown in FIG. 8, is substantially perpendicular to the scanning direction 55 of the electron beam 19 shown in FIG. The speed of the stage 31 and the speed of the Y stage 32 are determined.
[0084]
Here, in practice, unevenness in the moving speed of each stage and unevenness in the electron beam scanning position due to unevenness in the deflection control of the electron beam 19 exist. Since it is difficult to perform the defect determination, it is only necessary to maintain the accuracy at which there is no problem in the defect determination using the acquired image.
[0085]
Further, while scanning the electron beam 19, the X stage 31 and the Y stage 32 are moving, so that the actual scanning direction of the electron beam is determined in consideration of the movement of the X stage 31 and the Y stage 32. There is a need. As shown in FIG. 9, the following angle δ is obtained by the method described with reference to FIG. 4 in consideration of the angle θ of the rotational deviation amount with respect to the X-axis direction, and the actual scanning angle is obtained. By scanning the electron beam 19 in this manner, it is possible to obtain an image in which the angle θ of the rotational deviation has been corrected, as in the case described with reference to FIGS.
[0086]
As a result of the above, scanning along the image acquisition area is performed and the deflection distortion amount is distributed at the scanning center, so that the total deflection amount in scanning the image acquisition area is minimized, and the deflection distortion per pixel is minimized, It is possible to prevent erroneous determination of a defect in the inspection by comparing two images.
[0087]
As described above, according to the present embodiment, it is possible to obtain a high-quality image with less deflection distortion per pixel, which is suitable for the comparative inspection, to reduce erroneous detection, and to improve the reliability as an inspection device. An inspection method and an inspection apparatus that can be provided. Further, by applying the inspection apparatus according to the present invention to a semiconductor manufacturing process, it is possible to quickly and accurately detect the occurrence of an abnormality, thereby providing an excellent effect that a large number of defects can be prevented from occurring. . Furthermore, as a result, the occurrence of defects can be reduced, so that the reliability of semiconductor devices and the like can be increased, and the excellent effects of improving the development efficiency of new products and the like and reducing the manufacturing cost can be obtained. .
[0088]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain the defect of the sample by reducing the influence of the deflection distortion of the image signal of the sample obtained by scanning the charged particle beam while moving or stopping the sample stage. There is an effect that an inspection apparatus and an inspection method using a charged particle beam can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing the configuration of a SEM type visual inspection device.
FIG. 2 is an enlarged view of a portion irradiated with an electron beam.
FIG. 3 is an enlarged view of a portion irradiated with an electron beam.
FIG. 4 is a schematic diagram for explaining a scanning deflection direction of an electron beam corresponding to FIG. 3;
FIG. 5 is an enlarged view of a portion irradiated with an electron beam.
FIG. 6 is an enlarged view of a portion irradiated with an electron beam.
FIG. 7 is a schematic diagram illustrating a scanning deflection direction of an electron beam corresponding to FIG.
FIG. 8 is an enlarged view of a portion irradiated with an electron beam.
FIG. 9 is a schematic diagram illustrating the scanning deflection direction of the electron beam corresponding to FIG.
FIG. 10 is a flowchart showing the procedure of the inspection in FIG. 2;
FIG. 11 is a flowchart showing the procedure of the inspection in FIG. 3;
[Explanation of symbols]
1 SEM type visual inspection device, 9 sample, 15 scanning deflector, 19 electron beam,
Reference numeral 20: secondary electron detector, 31: X stage, 32: Y stage, 34: position monitor length measuring instrument, 49: defect determination unit, 51: secondary electron, 52: second secondary electron, 53: center , 54: optical axis, 55: scanning direction, 59: pitch, 60: image acquisition area.

Claims (12)

A stage composed of two members on each of which a sample is placed and movable in one direction, a charged particle source for generating a charged particle beam, and a charged particle beam generated by the charged particle source is irradiated to the sample and generated. Image forming means for detecting secondary charged particles and forming an image signal, wherein the center of an image acquisition area on the sample irradiated with the charged particle beam is the center of two-dimensional scanning by the charged particle beam. While the stage is stationary , the scanning direction of the irradiation of the charged particle beam is determined based on the moving speed and the moving direction of the stage, and the sample stage is continuously moved along one of two orthogonal biaxial directions. while when scanning spatially continuous image acquisition area by the charged particle beam, irradiation of the charged particle beam so that the center of the image acquisition area is the center of the two-dimensional scanning by said charged particle beam onto the sample To, from changes in the position monitor length meter by have been the height of the charged particle beam is determined by the position and the sample height gauge being irradiated position measurement of the irradiation position and the focal position of the charged particle beam An inspection apparatus using a charged particle beam, comprising: control means for calculating a shift, transmitting a correction signal to an objective lens and a blanking deflector, and performing scanning along an image acquisition area while correcting the correction . A charged particle source for generating a charged particle beam, lens means for focusing the charged particle beam on a sample on which a pattern is formed, a sample table on which the sample is mounted, and a sample including the sample table transferred to a sample chamber Transporting means, charged particle beam scanning means for scanning the charged particle beam on the sample, a detector for detecting secondary charged particles generated from the sample, and the sample based on a signal from the detector. Image forming means for forming a charged particle beam image signal of the first region above, storage means for storing the charged particle beam image signal, and a charged particle beam image signal stored in the storage means on the sample Comparing means for comparing a charged particle beam image signal of a second area in which the same pattern as the first area is formed, and defect determining means for determining a defect of the pattern from a comparison result of the comparing means. Detection using charged particle beam In the apparatus, a sample containing the sample stage in two perpendicular axial spatially moved by stationary, then allowed to continuously move the sample stage along a uniaxial of said biaxial, compared with the comparison means When scanning a spatially continuous image acquisition area including at least one of the first or second areas targeted by the charged particle beam, the center of the image acquisition area is determined by the charged particle beam. While irradiating the sample with the charged particle beam so as to be the center of two-dimensional scanning , the position where the charged particle beam was measured by a position monitor length measuring device and the position measured by a sample height measuring device were measured. calculating a deviation of the irradiation position and the focal position of the charged particle beam from the variation in the height position to be scanned along an image acquisition area while correcting by sending a correction signal to the objective lens and the blanking deflector Inspection apparatus using a charged particle beam, characterized. 3. The inspection apparatus according to claim 2, wherein each of the first and second regions is included in a separate one of the image acquisition regions. The device according to claim 3, further comprising: a rotation detecting unit configured to detect a rotation amount of the sample when the sample is placed on the sample stage; and a correction unit configured to correct the rotation amount. An inspection apparatus using a charged particle beam, wherein a rotation amount is corrected and an image of the image acquisition area is formed by the image forming unit. 5. The inspection apparatus according to claim 4, wherein the rotation amount correcting unit is a rotary stage mechanism that spatially rotates the sample including the sample stage. 5. The inspection apparatus according to claim 4, wherein the rotation amount correction unit corrects the rotation amount based on a scanning direction of the charged particle beam. 6. 3. The inspection apparatus according to claim 2, wherein the first or second area is included in one image acquisition area. The apparatus according to claim 7, further comprising a stage mechanism for spatially moving the sample stage, wherein the acquisition of the image of the image acquisition area based on the movement of the sample stage by the stage mechanism is performed by a set of electron optical system. An inspection apparatus using a charged particle beam, which is performed. A stage including an X stage, a Y stage, and a rotating stage; charged particle beam irradiation means for irradiating a sample mounted on the stage with a charged particle beam; and secondary electrons generated by irradiating the charged particle beam. Secondary electron detecting means for detecting at least one of the second secondary electrons generated by the secondary electrons being further reflected by the reflecting plate; and a defect of the sample based on a signal detected by the secondary electron detecting means. In the inspection apparatus using a charged particle beam provided with a defect detection means for detecting the center, a center detection means for detecting the center of the target area on the sample irradiated with the charged particle beam, and the optical axis setting means center is still the stage so that the center of the two-dimensional scanning by said charged particle beam, run of the irradiation of the charged particle beam based on the shape of the target region Scanning direction determining means for determining a direction and rotating the rotating stage based on the scanning direction to determine the direction of the sample, wherein the stage spatially moves the sample in orthogonal two-axis directions. is allowed to stand still, along said single axis of biaxially by continuously moving the specimen, the charged particle beam irradiation means irradiates the charged particle beam to said scanning direction determined by said scanning direction determining means The deviation of the irradiation position or the focal position of the charged particle beam from the fluctuation of the position where the charged particle beam is irradiated by the position monitor measuring device and the position measured by the sample height measuring device is changed. An inspection apparatus using a charged particle beam, wherein a scanning is performed along a target area while performing correction by performing a calculation and transmitting a correction signal to an objective lens and a blanking deflector . A secondary electron generated by irradiating a sample mounted on a stage including an X stage, a Y stage, and a rotating stage with a charged particle beam, or a secondary electron generated by the secondary electrons being further reflected by a reflector. In an inspection method using a charged particle beam that detects at least one of the secondary electrons and detects a defect of the sample based on the detected signal, a center of an image acquisition area on the sample that irradiates the charged particle beam is The stage is stopped so as to be the center of the two-dimensional scanning by the charged particle beam, a scanning direction of irradiation of the charged particle beam is determined based on a shape of the target area, and the rotating stage is determined based on the scanning direction. the rotate the stage is stationary spatially moving the sample in two orthogonal axial directions, said by continuously moving the sample along one axis of the two-axis, before the determined And irradiating said charged particle beam in the scanning direction, the charged from the height variation of the position measured by the position and sample height measuring device the charged particle beam measured is irradiated by the position monitor length measuring device Inspection using charged particle beam, which calculates the deviation of the irradiation position and focal position of the particle beam, sends a correction signal to the objective lens and blanking deflector, and scans along the target area while correcting Method. A stage composed of an X stage and a Y stage, charged particle beam irradiation means for irradiating a sample mounted on the stage with a charged particle beam, secondary electrons generated by irradiation of the charged particle beam or the secondary electrons Further detects at least one of the second secondary electrons generated by reflection on the reflection plate, and detects a defect of the sample based on a signal detected by the secondary electron detection means. In an inspection apparatus using a charged particle beam having a defect detection unit, a center detection unit that detects a center of a target region on the sample that irradiates the charged particle beam, and a center detected by the center detection unit is wherein the optical axis setting means for stationary the stage so that the center of the two-dimensional scanning with the charged particle beam, the irradiation of the charged particle beam based on the moving speed and the moving direction of the stage And a scanning direction determining means for determining a査direction, the spatially continuous image acquisition area while continuously moving the sample stage along a single axis of the biaxial direction the charged particle beam irradiation means perpendicular Scanning with a charged particle beam, the irradiation of the charged particle beam based on a change in the height of the position irradiated with the charged particle beam measured by a position monitor length measuring device and the height measured by a sample height measuring device An inspection apparatus using a charged particle beam, which calculates a displacement of a position or a focal position, transmits a correction signal to an objective lens and a blanking deflector, and performs scanning along a target area while performing correction . A sample placed on a stage composed of an X stage and a Y stage is irradiated with a charged particle beam, and at least the secondary electrons generated or the second secondary electrons generated by the secondary electrons being further reflected by a reflecting plate are generated. In the inspection method using a charged particle beam for detecting one and detecting a defect of the sample based on the detected signal, the center of an image acquisition area on the sample irradiated with the charged particle beam is determined by the charged particle beam. The stage is stopped so as to be the center of the two-dimensional scanning, the scanning direction of the irradiation of the charged particle beam is determined based on the moving speed and the moving direction of the stage, and then, of the orthogonal two axial directions, While continuously moving the sample stage along one axis, a spatially continuous image acquisition area is scanned with the charged particle beam, and the charged particle beam measured by a position monitor length measuring device is irradiated. While correcting by sending a correction signal to the location and the sample height from changes in the height of the measured position by the measuring instruments and calculates the deviation of the irradiation position and the focal position of the charged particle beam objective lens and the blanking deflector An inspection method using a charged particle beam, wherein scanning is performed along a target area.

Images