JP2004271269A - Pattern inspection method and pattern inspection device - Google Patents

Abstract

An object of the present invention is to provide a pattern inspection method capable of performing simple, quick, and reliable defect inspection even when performing a defect inspection of a pattern of a sample in a large area.
A pattern for irradiating a sample with an electron beam while scanning the sample to form sample images 40 'and 40 "based on charged particles generated from the sample and inspecting a pattern 40 of the sample based on the obtained sample image. In the inspection method, the electron beam scan area is set to the first area D1 including the sample image, the electron beam is scanned with respect to the sample to obtain a first sample image 40 ′, and the electron beam scan area is set to the first area. Unlike the area D1, the second area D2 including the sample image is set and the electron beam is scanned on the sample to obtain a second sample image 40 ″, and the first sample image 40 ′ and the second sample image 40 ″ are obtained. Are superimposed to obtain a composite sample image, and the defect inspection of the sample is performed by comparing the reference image 42 of the sample stored in advance with the composite sample image.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pattern inspection method and a pattern inspection apparatus used for a scanning electron microscope for performing inspection and length measurement of a sample such as a semiconductor element and a length measurement SEM.
[0002]
[Prior art]
Conventionally, a pattern of a sample is inspected using a scanning electron microscope or a length-measuring SEM. In a technical field of inspecting a semiconductor element or the like, various pattern inspection methods for inspecting a defect of the sample, An inspection device has been proposed (for example, see Patent Documents 1 and 2).
[0003]
For example, conventionally, there has been known a pattern inspection method of performing a so-called vector scan in which a minute scanning area limited along a contour (edge) of a pattern of a sample is two-dimensionally scanned to inspect the pattern.
[0004]
Further, by controlling the deflection coil of the electron microscope, the scanning direction of the electron beam (electron beam) is set oblique to the direction in which the line of the wiring pattern extends, and the electron beam is scanned on the semiconductor device to be measured, and the image of the wiring pattern is scanned. There is also known a pattern inspection method and a pattern inspection apparatus that obtains a pattern (for example, see Patent Literature 3 and Patent Literature 4).
[0005]
Further, there is also known a pattern inspection method and a pattern inspection apparatus in which a pattern image of a semiconductor device and a design CAD image of the pattern are superimposed and displayed (for example, see Patent Document 5).
[0006]
[Patent Document 1]
JP-A-63-210606 (FIGS. 3 and 4)
[Patent Document 2]
JP-A-9-313318 (paragraph number 0017, FIG. 3)
[Patent Document 3]
JP-A-9-265931
[Patent Document 4]
JP-A-10-3876
[Patent Document 5]
JP-A-2002-353280
[0007]
[Problems to be solved by the invention]
By the way, it is known that in a scanning electron microscope, a length measuring SEM, or the like, the resolution is low in a direction in which a contour line of a pattern parallel to a scanning direction (scanning direction) of an electron beam extends.
[0008]
In the conventional length measurement SEM, measurement is performed by focusing on a line segment perpendicular to the scanning direction. However, when performing defect inspection by comparing newly acquired two-dimensional image data with CAD data, scanning and scanning are performed. The low resolution in the direction in which the parallel contour lines extend causes a measurement error.
[0009]
The pattern inspection method using vector scanning can solve the problem that the resolution in the direction in which the contour line parallel to the scan extends is low. However, the pattern inspection method using vector scanning can be applied to the contour (edge) line of the pattern. Since this method is for inspecting a minute area along the surface, it takes a lot of trouble and time, and is not suitable for a pattern inspection method for inspecting a pattern of a sample in a large area.
[0010]
Further, in the pattern inspection method in which the sample image data of the sample pattern is simply superimposed on the CAD data, the deterioration of the resolution in the direction in which the contour line extending in parallel with the scan cannot be overcome, and there is a risk of overlooking the pattern defect.
[0011]
Further, in the pattern inspection method in which the scanning direction of the electron beam is oblique to the direction in which the contour line of the wiring pattern extends, a defect in the contour line portion of the pattern may be overlooked.
[0012]
The present invention has been made in view of the above circumstances, and its object is to enable simple, quick, and reliable defect inspection even when performing a defect inspection of a pattern of a large area sample. It is to provide a pattern inspection method and a pattern inspection device.
[0013]
[Means for Solving the Problems]
The pattern inspection method according to claim 1, wherein a sample image is formed based on charged particles generated from the sample by irradiating the sample with an electron beam while scanning, and a pattern of the sample is inspected based on the obtained sample image. In the pattern inspection method
The electron beam scan area is set to a first area including the sample image, the electron beam is scanned with respect to the sample to obtain a first sample image, and the electron beam scan area is set to the first area. Unlike this, a second area including the sample image is set, the electron beam is scanned on the sample to obtain a second sample image, and the first sample image and the second sample image are superimposed. A composite sample image is obtained by comparing the reference image of the sample stored in advance with the composite sample image, and a defect inspection of the sample is performed.
[0014]
The pattern inspection method according to claim 2, wherein a sample image is formed based on charged particles generated from the sample by irradiating the sample with an electron beam while scanning the same, and a pattern of the sample is inspected based on the obtained sample image. In the pattern inspection method
A scan area of the electron beam is set to a first area including the sample image, the electron beam is scanned with respect to the sample to obtain a first sample image, and a reference image of the sample stored in advance and the A sample defect image based on the first sample image is obtained by comparing the sample image with the one sample image, and the electron beam scan area is set to a second area including the sample image different from the first area. Is scanned with respect to the sample to obtain a second sample image, and the reference image and the second sample image are compared to obtain a sample defect image based on the second sample image. A defect inspection of the sample is performed by synthesizing a sample defect image based on the sample image and a sample defect image based on the second sample image.
[0015]
In the pattern inspection method according to the third aspect, in the pattern inspection method according to the first or second aspect, the angle for shifting the scan area of the electron beam with respect to the line direction of the pattern of the sample image is automatically set. It is characterized by what is required.
[0016]
The pattern inspection apparatus according to claim 4, wherein the sample mounting means for mounting the sample, an electron beam irradiating means for irradiating the sample with an electron beam while scanning the sample, and charged particles generated from the sample. A sample image forming unit for forming an image, and a storage unit storing a reference image of the sample in advance, and comparing the obtained pattern of the sample image with the reference image to obtain a pattern of the sample. A pattern inspection apparatus having arithmetic control means for inspecting, wherein the arithmetic control means rotates and shifts a scanning direction of an electron beam including the sample image and a line direction of a pattern of the sample image by using the electron beam. The irradiation unit or the sample mounting unit is controlled to scan the shifted first region to obtain a first sample image, and scan the second region including the sample image different from the first region to obtain a second sample image. Controlling the electron beam irradiating means or the sample image forming means to obtain a sample image, and combining the first sample image and the second sample image to obtain a combined sample image; A defect inspection of the sample is performed by comparing a reference image with the composite sample image.
[0017]
The pattern inspection apparatus according to claim 5, wherein the sample mounting means for mounting the sample, an electron beam irradiating means for irradiating the sample while scanning the electron beam, and charged particles generated from the sample A sample image forming unit for forming a sample image; and a storage unit in which a reference image of the sample is stored in advance. A pattern inspection apparatus having an arithmetic control unit for inspecting the pattern of the sample by comparing the pattern of the sample image obtained with the reference image, wherein the arithmetic control unit scans an electron beam including the sample image. The electron beam irradiating means or the sample mounting means is controlled to rotate and shift the line direction of the pattern of the region and the pattern of the sample image, and a first sample image is acquired by scanning in the shifted first region. A sample defect image based on the first sample image is obtained in comparison with a reference image, and a second region including the sample image is scanned differently from the first region to obtain a second sample image, and compared with the reference image. And obtaining a sample defect image based on the second sample image, combining the sample defect image based on the first sample image and the sample defect image based on the second sample image, and performing a defect inspection of the sample. Features.
[0018]
7. The pattern inspection apparatus according to claim 6, wherein the arithmetic control unit is configured to set a line of the pattern of the sample image to set a scanning direction of the electron beam. It is characterized in that an angle to be shifted with respect to the direction is automatically obtained.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
<Embodiment 1>
FIG. 1 shows the overall configuration of a pattern inspection apparatus used for a pattern inspection method according to the present invention.
[0020]
In FIG. 1, reference numeral 10 denotes a disk-shaped movable table as a sample mounting means for mounting a sample 11 such as a semiconductor wafer or chip. This pattern inspection apparatus generally includes a scanning electron microscope 12, a host computer (operation control means) 13, and a monitor 14.
[0021]
The scanning electron microscope 12 includes an electron gun 16 provided above a lens barrel 15, a condenser lens coil 17, an X-direction deflection coil 18, a Y-direction deflection coil 19, a detector (charged particle detecting means) 20, an objective lens coil. 21.
[0022]
The electron lens 16, the condenser lens coil 17, the X-direction deflection coil 18, the Y-direction deflection coil 19, and the objective lens coil 21 constitute an electron beam irradiation unit, and the electron beam 16 a emitted from the electron gun 16 is used for the condenser lens coil 17. Then, the sample 11 is irradiated through the objective lens coil 21. The electron beam 16a is appropriately deflected by the X-direction deflection coil 18 and the Y-direction deflection coil 19 via the X-direction scan control circuit 18A and the Y-direction scan control circuit 19A.
[0023]
Then, the detector 20 detects a secondary electron beam or the like from the sample 11 generated by the irradiation of the electron beam 16a. The detection signal is input to the host computer 13, and the host computer 13 functions as a sample image forming means for appropriately processing the detection signal to form a sample image. The image processing result is output to the monitor 14, Is displayed as a sample image on the screen 14A.
[0024]
The moving table 10 is installed in the sample chamber 22 in a vacuum state. The movable table 10 is movable in the X direction and the Y direction orthogonal to each other. The movement in the X direction and the Y direction is performed by an X direction actuator 23, an X direction feed screw 24, an X direction guide bar 25, a Y direction actuator 26, a Y direction feed screw 27, and a Y direction guide bar 28 as shown in FIG. Done. The X-direction actuator 23 is controlled by an X-direction actuator control circuit 29, and the Y-direction actuator 26 is controlled by a Y-direction actuator drive control circuit 30.
[0025]
An X-direction movement command value setting device 31 is connected to the X-direction actuator drive control circuit 29, and a Y-direction movement command value setting device 32 is connected to the Y-direction actuator drive control 30. Control signals are input from the host computer 13 to the X direction movement command value setting device 31 and the Y direction movement command value setting device 32.
[0026]
The movable table 10 is moved to the position of the sample to be measured, and the sample image 11a is displayed on the screen 14A of the monitor 14 by irradiating the charged particles to the field of view 11 'to be measured, for example, by irradiating the field of view 11' of 10000 times. Is displayed.
[0027]
A CAD data storage device 13a is connected to the host computer 13. The CAD data storage device 13a stores, for example, CAD data as a design drawing indicating a pattern to be formed on a wafer as the sample 11.
[0028]
Here, the pattern formed on the wafer is a stepped pattern 40 as shown in FIG. 3, and the stepped pattern 40 is repeatedly formed on the wafer as shown in FIG. The step-shaped pattern 40 is called from the CAD data storage device 13a and used as a reference image 42 (see FIG. 5F) when performing a defect inspection of the pattern formed on the sample 11.
[0029]
When performing the defect inspection, the host computer 13 automatically acquires the scanning direction of the electron beam 16a from the extending direction of the contour line 40a of the pattern 40 of the sample 11 based on the CAD data.
[0030]
Then, the host computer 13 automatically calculates the raster scan angle θ with respect to the direction in which the contour line 40a extends from the CAD data. The host computer 13 controls the deflection coils 18 and 19 using the angle θ.
[0031]
As a result, the sawtooth currents SX and SY generated by the scanning power supplies of the deflection coils 18 and 19 are divided into function values of sin θ and cos θ, and the current signals are added by the adders and supplied to the deflection coils 18 and 19. Then, the scanning direction (raster scanning direction) of the electron beam 16a on the sample 11 is rotated by an angle θ with respect to the direction in which the contour line 40a extends.
[0032]
This relational expression is shown below.
X = SX sin θ + SY cos θ
Y = −SXcos θ + SY sin θ
Thereby, as shown in FIG. 5A, the electron beam 16a sets the pattern 40 of the sample 11 in the first direction (first region) D1 at an angle θ with respect to the direction in which the contour line 40a extends. Perform raster scan.
[0033]
As a result, a pattern image 40 'as a first sample image shown in FIG. 5B is obtained. In FIG. 5B, reference numeral 40 b ′ denotes a defect image corresponding to the defect 40 b of the pattern 40.
[0034]
Next, the host computer 13 controls the deflection coils 18 and 19 so that the scanning direction of the electron beam 16a is in a second direction D2 which is 90 degrees with respect to the first direction D1. As a result, the electron beam 16a raster-scans the pattern 40 of the sample 11 by setting the electron beam 16a in a second direction (second region) D2 orthogonal to the first direction, as shown in FIG. 5C.
[0035]
As a result, a pattern image 40 ″ as a second sample image shown in FIG. 5D is obtained. In FIG. 5D, reference numeral 40b ″ indicates a defect portion image corresponding to the defect portion 40b of the pattern 40. ing.
[0036]
The host computer 13 functions as an image synthesizing unit, and superimposes the pattern image 40 ′ as the first sample image and the pattern image 40 ″ as the second sample image to form a synthesized image as shown in FIG. 5 (E), reference numeral 41b denotes a defective portion image 41b corresponding to the defective portion 40b of the pattern 40.
[0037]
By combining the first sample image and the second sample image, if the pattern 40 has a defect 40b, the defect image 41b corresponding to the defect 40b is clarified.
[0038]
The host computer 13 then compares the pattern image 41 with a reference image 42 as a staircase-shaped pattern 40 as a design drawing, and determines whether or not the pattern 40 has a defective portion 40b.
[0039]
When the defect inspection for one visual field 11 'is completed, the host computer 13 controls the moving platform 10 in the directions of arrows A1 to A4 shown in FIG. Perform a defect inspection of
[0040]
Further, a corner portion indicated by reference numeral 40c in FIG. 6A 'and a corner portion indicated by reference numeral 40d in FIG. 6C are obtained by scanning with an electron beam as indicated by reference numeral 40c' in FIG. In FIG. 6 (D ′), it looks like a rounded defective portion image and a reference numeral 40d ′, and it may not be possible to determine whether or not the image is a true defective portion image.
[0041]
Therefore, first, the scanning region of the electron beam is set to the first region, a pattern image 40 ′ as a first sample image is acquired, and this is compared with a reference image 42 (see FIG. 6 (E ′)). A sample defect image is obtained, and then the scanning area of the electron beam is set to the second area to obtain a pattern image 40 ″ as a second sample image, and this and a reference image 42 (see FIG. 6E). Are compared to obtain a sample defect image, and thereafter, these sample defect images are combined to obtain a pattern image 41 (see FIG. 6 (F ′)).
[0042]
Thereby, the defect portion image 41b is clarified, and it is clarified whether or not the pattern 40 of the sample 11 has the defect portion 40b.
[0043]
Here, the direction of the raster scan of the electron beam 16a is inclined by the angle θ with respect to the direction in which the contour line 40a of the pattern 40 extends. However, as shown in FIG. A first sample image is obtained by raster scanning with the horizontal direction in which the contour line 40a extends as a first direction D1, and then, as shown in FIG. 7B, in a second direction D2 orthogonal to the first direction D1. The raster scan direction of the electron beam 16a is set, the same field of view 11 'of the sample 11 is raster-scanned to obtain a second sample image, and the first sample image and the second sample image are combined to obtain the image shown in FIG. A pattern image 41 as a composite image shown in FIG. 7C may be obtained, and the pattern image 41 may be compared with a reference image 42 shown in FIG.
[0044]
In the first embodiment of the present invention, a first direction D1 extending the contour line 40a and a second direction D2 orthogonal to the first direction D1 are set, and the sample 11 is scanned to acquire two sample images. Although the defect of the sample 11 is inspected by synthesizing the sample images, the angle between the first direction D1 and the second direction D2 may be 90 degrees or less.
[0045]
As described above, in the first embodiment of the invention, the angle of the raster scan with respect to the sample 11 is set by the control of the deflection coils 18 and 19 by the host computer 13. It is also possible to perform a raster scan in the direction D1 and the second direction D2 to obtain the pattern images 40 ′ and 40 ″ and inspect the defect of the pattern 40 of the sample.
[0046]
<Embodiment 2>
Here, the viewing area 11 'is scanned not in a direction orthogonal to the direction but in a parallelogram shape excluding a rectangle by giving a skew angle to the scan.
[0047]
Scan rotation with skew angle added
X = SXsin (θ + φ) + SYcosθ
Y = −SXcos (θ + φ) + SYsinθ
The scan of the electron beam 16a becomes a parallelogram with respect to the sample 11 due to the superposition of the scan angle φ.
[0048]
As a result, each visual field region 11 'of the sample 11 is scanned in a parallelogram shape as shown in FIG.
[0049]
For example, in the skew scan rotation, the field of view 11 'is scanned as shown in FIGS. 9A and 9C.
[0050]
As shown in FIG. 9A, the host computer 13 causes the electron beam 16a to skew scan the pattern 40 of the sample 11 in the first direction D1 at an angle φ with respect to the direction in which the contour line 40a extends.
[0051]
As a result, a pattern image 40 'as the first sample image shown in FIG. 9B is obtained. In FIG. 9B, reference numeral 40 b ′ indicates a defect image corresponding to the defect 40 b of the pattern 40.
[0052]
Next, the host computer 13 controls the deflection coils 18 and 19 so that the scanning direction of the electron beam 16a is in a second direction D2 which is 90 degrees with respect to the first direction D1. Thus, the electron beam 16a skew-scans the pattern 40 of the sample 11 in the second direction D2 orthogonal to the first direction, as shown in FIG.
[0053]
As a result, a pattern image 40 ″ as a second sample image shown in FIG. 9D is obtained. In FIG. 9D, reference numeral 40B ″ indicates a defect portion image corresponding to the defect portion 40b of the pattern 40. ing.
[0054]
The pattern images 40 'and 40 "obtained by FIGS. 9B and 9D are different from the images which the observer expects in design. The conversion is performed, and the shaped images 41 'and 41 "shown in FIGS. 9E and 9F are displayed on the screen 14A.
[0055]
The host computer 13 functions as an image synthesizing unit, and superimposes the shaped image 41 ′ as the first sample image and the shaped image 41 ″ as the second sample image to form a synthesized image as shown in FIG. 9 (G), reference numeral 41b denotes a defective portion image 41b corresponding to the defective portion 40b of the pattern 40.
[0056]
By combining the first sample image and the second sample image, if the pattern 40 has a defect 40b, the defect image 41b corresponding to the defect 40b is clarified.
[0057]
Next, the host computer 13 compares the pattern image 41 with a reference image 42 (see FIG. 9H) as a staircase pattern 40 as a design drawing, and determines whether or not the pattern 40 has a defective portion 40b. .
[0058]
Further, a corner portion indicated by reference numeral 40c in FIG. 10A 'and a corner portion indicated by reference numeral 40d in FIG. 10C are obtained by scanning with an electron beam as indicated by reference numeral 40c' in FIG. In FIG. 10 (D '), it looks like a rounded defective portion image and a symbol 40d' in FIG.
[0059]
Accordingly, first, the scan area of the electron beam is set to the first area to obtain the pattern image 40 ′ as the first sample image, and this is shaped to obtain the shaped image 41 ′ (see FIG. 10 (E ′)). After that, the shaped image 41 ′ is compared with the reference image 42 (see FIG. 10 (G ′)) to obtain a sample defect image. Then, the electron beam scan area is set to the second area and After obtaining a pattern image 40 ″ as a two-sample image and shaping it to obtain a shaped image 41 ″ (see FIG. 10 (F ′)), the shaped image 41 ″ and a reference image 42 (see FIG. )) To obtain a sample defect image, and then synthesize these sample defect images to obtain a pattern image 41 (see FIG. 10 (H ′)).
[0060]
Thereby, the defect portion image 41b is clarified, and it is clarified whether or not the pattern 40 of the sample 11 has the defect portion 40b.
[0061]
When the defect inspection for one visual field 11 'is completed, the host computer 13 controls the moving platform 10 in the directions of arrows A1 to A4 shown in FIG. Perform a defect inspection of
[0062]
In the second embodiment of the present invention, a first direction D1 extending the contour line 40a and a second direction D2 orthogonal thereto are set, and the sample 11 is skew-scanned to acquire two sample images. Although the defect of the sample 11 is inspected by combining two sample images, the angle between the first direction D1 and the second direction D2 may be 90 degrees or less.
[0063]
According to the second embodiment of the present invention, since the scanning can be performed at an angle with respect to the horizontal line, the resolution of the horizontal contour line 40a can be prevented from deteriorating.
[0064]
Further, even when the large area of the sample is inspected by moving the sample stage 10, the scanning can be performed by overlapping the parallelogram-shaped visual field areas, so that a useless area can be prevented from being generated in the scanning.
[0065]
The sample stage 10 is mechanically rotated, and the pattern and the scan are relatively rotated and shifted so that the raster scan is oblique to the direction in which the contour line 40a of the pattern 40 extends, and then the first direction D1 And a skew scan in the second direction D2 to obtain pattern images 40 ′ and 40 ″, thereby inspecting the pattern 40 of the sample for defects.
[0066]
【The invention's effect】
Since the present invention is configured as described above, even when performing a defect inspection of a pattern of a sample in a large area, the defect inspection can be performed simply, quickly, and reliably.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a pattern inspection apparatus according to the present invention.
FIG. 2 is a diagram showing an example of a sample mounting table shown in FIG.
FIG. 3 is a diagram illustrating an example of a pattern formed on a sample.
FIG. 4 is an explanatory diagram showing a relationship between a repetitive pattern formed on a sample and a visual field region.
FIG. 5 is an explanatory diagram showing an example of the pattern inspection method according to the first embodiment of the present invention, in which (A) raster-scans the sample in a first direction oblique to the direction in which the contour line of the pattern extends; (B) shows a first sample image obtained by the raster scan shown in (A), and (C) shows a state in which the sample is raster-scanned in a second direction orthogonal to the first direction. (D) shows a second sample image obtained by the raster scan shown in (B), and (E) shows a combined image obtained by combining the first sample image and the second sample image. , (F) show reference images to be compared with the composite image.
FIG. 6 is an explanatory diagram showing another example of the pattern inspection method according to the first embodiment of the present invention, wherein (A ′) is a first direction (first direction) oblique to the direction in which the contour line of the pattern extends; (A) shows a state in which the sample is raster-scanned, (B ′) shows a first sample image obtained by the raster scan shown in (A ′), and (C ′) shows a first sample image orthogonal to the first direction. (D ') shows the second sample image obtained by the raster scan shown in (B'), and (E ') shows the first sample image and the second sample image. A synthesized image obtained by synthesizing the sample image is shown, and (F ′) indicates a reference image to be compared with the synthesized image.
FIGS. 7A and 7B are explanatory views showing still another example of the pattern inspection method according to the first embodiment of the present invention, wherein FIG. 7A shows a sample in a first direction oblique to the direction in which the contour line of the pattern extends; (B) shows a state where the sample is raster-scanned in a second direction orthogonal to the first direction, and (C) shows a state where the first sample image and the second sample image are combined. (D) shows a reference image to be compared with the composite image.
FIG. 8 is a diagram showing an example of the pattern inspection method according to the second embodiment of the present invention, showing a state in which the visual field region is skew-scanned into a parallelogram.
FIG. 9 is an explanatory view showing an example of a pattern inspection method according to the second embodiment of the present invention, in which (A) performs skew scanning of a sample in a first direction with respect to a direction in which a contour line of a pattern extends. (B) shows a first sample image obtained by the skew scan shown in (A), and (C) shows a state in which the sample is skew-scanned in a second direction orthogonal to the first direction. (D) shows a second sample image obtained by the skew scan shown in (B), (E) shows a shaped image of the first sample image, and (F) shows a shaped image of the second sample image. (G) shows a combined image obtained by combining the shaped image of the first sample image and the shaped image of the second sample image, and (H) shows a reference image to be compared with the synthesized image. .
FIG. 10 is an explanatory view showing another example of the pattern inspection method according to the second embodiment of the present invention, wherein (A ′) is a first direction (first region) with respect to a direction in which the contour line of the pattern extends. (B) shows a first sample image obtained by the skew scan shown in (A '), and (C') shows a second sample orthogonal to the first direction. (D ') shows a second sample image obtained by the skew scan shown in (B'), and (E ') shows the first sample. (F ′) shows a shaped image of the second sample image, and (G ′) shows a shaped image of the first sample image and a shaped image of the second sample image. (H ′) indicates a reference image to be compared with the composite image.
[Explanation of symbols]
11 ... sample
11 ': Viewing area
40 ... pattern
40 ': Pattern image (first sample image)
40 "... pattern image (second sample image)
42 ... Reference image
D1... First direction (first region)
D2: Second direction (second area)

Claims (6)

In a pattern inspection method of forming a sample image based on charged particles generated from the sample by irradiating the sample while scanning the electron beam, and inspecting the pattern of the sample based on the obtained sample image,
The electron beam scan area is set to a first area including the sample image, the electron beam is scanned with respect to the sample to obtain a first sample image, and the electron beam scan area is set to the first area. Unlike this, a second area including the sample image is set, the electron beam is scanned on the sample to obtain a second sample image, and the first sample image and the second sample image are superimposed. A composite sample image obtained by the method, a reference image of the sample stored in advance is compared with the composite sample image, and a defect inspection of the sample is performed. In a pattern inspection method of forming a sample image based on charged particles generated from the sample by irradiating the sample while scanning the electron beam, and inspecting the pattern of the sample based on the obtained sample image,
A scan area of the electron beam is set to a first area including the sample image, the electron beam is scanned with respect to the sample to obtain a first sample image, and a reference image of the sample stored in advance and the A sample defect image based on the first sample image is obtained by comparing the sample image with the one sample image, and the electron beam scan area is set to a second area including the sample image different from the first area. Is scanned with respect to the sample to obtain a second sample image, and the reference image and the second sample image are compared to obtain a sample defect image based on the second sample image. A sample defect image based on the second sample image and a sample defect image based on the second sample image, and performing a defect inspection of the sample. 3. The pattern inspection method according to claim 1, wherein an angle at which the scan area of the electron beam is shifted with respect to a line direction of the pattern of the sample image is automatically obtained. Sample mounting means for mounting the sample, electron beam irradiating means for irradiating the sample while scanning an electron beam, and sample image forming means for forming a sample image by charged particles generated from the sample A storage unit in which a reference image of the sample is stored in advance, and a calculation control unit for inspecting the pattern of the sample by comparing the pattern of the obtained sample image with the reference image. In the inspection device,
The arithmetic control unit controls the electron beam irradiation unit or the sample mounting unit to rotate and shift the line direction of the pattern of the sample image and the scan area of the electron beam including the sample image, and The electron beam irradiating means or the sample for acquiring a first sample image by scanning in one area and acquiring a second sample image by scanning in a second area including the sample image differently from the first area; Controlling the image forming means to obtain a synthesized sample image by synthesizing the first sample image and the second sample image; comparing a reference image of the sample stored in advance with the synthesized sample image; A pattern inspection apparatus for performing a defect inspection of a pattern. Sample mounting means for mounting a sample, electron beam irradiating means for irradiating the electron beam on the sample while scanning the sample, and sample image forming means for forming a sample image by charged particles generated from the sample And storage means for storing the reference image of the sample in advance, and having storage means for storing the pattern of the obtained sample image and the pattern in advance, the pattern of the obtained sample image and the reference image, A pattern inspection apparatus having an arithmetic control unit for inspecting the pattern of the sample by comparing
The arithmetic and control unit controls the electron beam irradiation unit or the sample mounting unit to rotate and shift the line direction of the scan area of the electron beam including the sample image and the pattern of the sample image. A first sample image is acquired by scanning in one area, and a sample defect image based on the first sample image is obtained by comparing with the reference image, and is scanned in a second area different from the first area and including the sample image. To obtain a sample defect image based on the second sample image by comparing with the reference image, and obtain a sample defect image based on the first sample image and a sample defect image based on the second sample image. A pattern inspection apparatus for performing a defect inspection of the sample by combining the above. 6. The pattern inspection apparatus according to claim 4, wherein the arithmetic control unit automatically obtains an angle shifted from a line direction of the pattern of the sample image in order to set a scan direction of the electron beam. A pattern inspection apparatus characterized by the above-mentioned.

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