JPH09311112A - Defect inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mask inspection device by which the defect in the pattern of a sample can be quickly and accurately inspected. SOLUTION: A plurality of electron beams EB11 to EB31 formed by a mask 3 are simultaneously scanned on the region corresponding to a plurality of regions of a sample 8 by means of deflectors 4a and 4b, and the secondary electrons SE11 to SE31 from the sample 8 are introduced to detectors M11 to M31 by means of a multilens 9 having lens apertures 901, 902, and 903 so as to be detected respectively. As a result, the pattern in a plurality of regions of the sample 8 can be simultaneously inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus capable of inspecting a circuit pattern on a mask, a reticle or a wafer (hereinafter referred to as a sample) for defects at high speed and with high accuracy.

[0002]

2. Description of the Related Art In a conventional inspection apparatus, a probe such as an electron beam that is narrowed down is scanned over a sample to detect secondary electrons generated from the sample by a detector, and a signal from the detector is processed. A pattern defect is detected.

[0003]

However, since only one probe scans the sample in the related art, for example,
In the case of detecting a defect of about 0.1 μm, it takes a long time to scan the entire surface of the sample with the probe, which has a drawback of low throughput. On the other hand, if high-speed scanning is performed to reduce the scanning time, the
Since the S / N ratio of the secondary electron signal is small, there is a problem that false detections increase.

It is an object of the present invention to provide a mask inspection apparatus capable of inspecting a sample pattern for defects at high speed and with high accuracy.

[0005]

An embodiment of the invention will be described with reference to FIGS. (1) Describing in association with FIG. 1, the defect inspection apparatus according to the invention of claim 1 has a plurality of charged particle beams EB11 to EB31.
Are scanned on the sample 8 and the electrons SE11 to SE31 from the sample 8 are scanned.
Is detected for each of the charged particle beams EB11 to EB31 to inspect the pattern defect on the sample 8 to achieve the above object. (2) The invention of claim 1 is a sample 8 on which a pattern is formed.
A beam for forming a plurality of charged particle beams EB11 to EB31 by applying a charged particle beam EB11 to EB31 to the sample and detecting electrons SE11 to SE31 from the sample 8 to detect a defect of the pattern. Forming means 3, charged particle beam deflectors 4a and 4b for simultaneously scanning each of the charged particle beams EB11 to EB31 on a corresponding region of a plurality of regions provided on the sample 8, and electrons SE11 to SE11 from the sample 8. SE
A multi-detector having detectors M11 to M31 for detecting 31 respectively, and a plurality of electron lenses 901 and 9 for guiding electrons SE11 to SE31 from the sample 8 to the detectors M11 to M31, respectively.
And a multi-electron lens device 9 having 02,903 to achieve the above-mentioned object. (3) Explaining in association with FIG. 2, the invention of claim 3 is the defect inspection apparatus according to claim 1 or 2.
On the axis AX21 where the incident direction of the charged particle beams EB11 to EB31 to the sample 8 is different from the normal direction of the sample surface, and the specular reflection condition is satisfied with respect to the incident axis of the charged particle beams EB11 to EB31 incident on the sample surface. A detector M21 on the axes AX11, AX31
Detectors M11 and M31 are provided in the vicinity of, respectively. (4) Explaining in association with FIG. 3, the invention of claim 4 is the defect inspection apparatus according to claim 3, wherein the beam forming means is a substrate 3 having a plurality of holes 3a, and a plurality of holes 3
The positions of the plurality of holes 3a in the optical axis direction were shifted so that the optical path lengths of the charged particle beams EB11 to EB31 from a to the sample surface were all equal. (5) The invention of claim 5 is the defect inspection apparatus according to claim 3, wherein the beam forming means has a substrate 3 having a plurality of holes 3a and a holding table 11 for holding the substrate 3.
Charged particle beams EB11 to EB from the plurality of holes 3a to the sample surface
The holding table 11 is configured to hold the substrate 3 tilted with respect to the sample surface so that all the optical path lengths of 31 are equal. (6) Describing in association with FIG. 5, the invention of claim 6 is the defect inspection apparatus according to any one of claims 1 to 5, wherein the plurality of electron lenses 181 to 183 are irradiated with charged particles on the sample 8. The plurality of detectors M11 to M31 are arranged on a first spherical surface centered on a point and are concentric with the first spherical surface.
On the second spherical surface having a radius larger than that of the spherical surface. (7) The invention of claim 7 is the defect inspection apparatus according to any one of claims 1 to 5, wherein the plurality of electron lenses are a plurality of lenses formed on a non-magnetic metal plate to which a first potential is applied. Apertures 181 to 183, the plurality of lens apertures 181 to 183 and the plurality of detectors M11 to M31.
A second electric potential higher than the first electric potential is applied between
A multi-aperture plate 19 is provided for guiding the electrons in a predetermined area among the electrons that have passed through the lens apertures 181 to 183 to the detectors M11 to M31. (8) The invention of claim 8 is the defect inspection apparatus according to claim 7, wherein a plurality of lens apertures 181 to 183 are arranged on a first spherical surface centered on a charged particle irradiation point on the sample 8. , A plurality of openings 191 to 193 formed in the multi-aperture plate 19 are respectively arranged on a second spherical surface which is concentric with the first spherical surface and has a radius larger than the first spherical surface,
A plurality of detectors M11 to M31 are arranged on a third spherical surface which is concentric with the second spherical surface and has a radius larger than that of the second spherical surface. (9) Describing in association with FIG. 2, the invention of claim 9 is, in the defect inspection apparatus according to claim 8, a specular reflection condition with respect to the incident axes of the charged particle beams EB11 to EB31 incident on the sample surface. The larger the angle between the axes AX11 to AX31 satisfying the above and the axes J11 to J31 passing through the charged particle beam irradiation point on the sample 8 and the centers of the lens apertures 181 to 183, the larger the opening area of the lens apertures 181 to 183 becomes. did. (10) Describing in association with FIG. 4, the invention of claim 10 is the defect inspection apparatus according to any one of claims 1 to 9, in which the electron SE 11 passing through the multi-electron lens device 9 is used.
~ Electron deflector 16 for deflecting SE31 respectively, and electron deflector 16 is controlled in synchronization with the deflection of charged particle beam deflector 15 so that electrons SE11 to SE31 respectively enter detectors M11 to N31. And a control means 17 for controlling. (11) Describing in association with FIG. 5, the invention of claim 11 is the defect inspection apparatus according to claim 10, wherein an electric field of the electron deflector 16 is provided between the electron lens device 18 and the electron deflector 16. A shield 20 is provided to shield the above. (12) Describing in association with FIG. 2, the invention of claim 12 is the defect inspection apparatus according to any one of claims 2 to 11, wherein a plurality of charged particle beams EB11 to EB36 formed by the beam forming means. In the array distribution of, the number of charged particle beams imaged in the first direction (x direction) in which the optical path length to the irradiation surface of the sample 8 changes is the second direction (y Direction) is smaller than the number of charged particle beams that are imaged.

(1) According to the second aspect of the invention, the charged particle beams EB11 to EB31 formed by the beam forming means 3 are placed on the corresponding regions of the sample 8 by the charged particle beam deflectors 4a and 4b. Scan at the same time with the electron S from the sample 8.
E11 to SE31 are guided to detectors M11 to M31 by a multi-electron lens device 9 having electron lenses 901, 902 and 903, and detected. (2) In the invention of claim 3, charged particle beams EB11 to EB31 are used.
The direction of incidence on the sample 8 and the direction normal to the sample surface are different,
Make it obliquely incident. (3) In the invention of claim 4, the charged particle beams EB11 to EB from the plurality of holes 3a formed in the beam forming means to the sample surface.
The optical path lengths of B31 are all the same. (4) In the invention of claim 5, the holding table 11 has the plurality of holes 3
The substrate 3 is held tilted with respect to the sample surface so that the optical path lengths of the charged particle beams EB11 to EB31 from a to the sample surface are all equal. (5) According to the invention of claim 7, the lens apertures 181 to 1 are set by applying a potential higher than that of the plurality of lens apertures 181 to 183 to the multi-aperture plate 19.
The electrons SE11 to SE31 that have passed through 83 are detectors M11 to M31.
Be led to. (6) In the invention of claim 9, the lens apertures 181 to 18 in the direction in which the emission probability of the electrons SE11 to SE31 is small.
The opening area was increased by about 3. Therefore, the detector M
The amount of electrons incident on 11 to M31 is leveled. (7) In the invention of claim 10, the multi-electron lens device 9
The electrons SE11 to SE31 which have passed through the electron deflector 16 and the detectors M11 to N31, respectively.
~ SE31 so that they respectively enter the charged particle beam deflector 15
When the charged particle beams EB11 to EB31 are scanned by the
So that the electrons SE11-SE31 from the electron impinge on each of the detectors M11-N31.
Deflect. (8) In the invention of claim 11, the shield 20 shields the electric field of the electron deflector 16 with respect to the electron lens device 18.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to the embodiment.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First Embodiment FIG. 1 is a diagram for explaining the first embodiment of the defect inspection apparatus according to the present invention, and shows the main part of the apparatus. The electron beam emitted from the electron gun 1 is made into a beam parallel to the optical axis by the condenser lens 2, and the mask 3 held by the holding table 11 is irradiated with the beam. A plurality of holes 3 a are formed in the mask 3. In the present embodiment, the 1 μm square holes have a pitch of 1
In mm, 6 rows are provided in the y-axis direction and 3 columns are provided in the direction orthogonal to the y-axis. When the mask 3 is irradiated with an electron beam, the electrons passing through the hole 3a generate 18 electron beams EB11-
EB36 is formed. In FIG. 1, three electron beams EB11, EB21 and EB formed on the same plane as the paper surface.
Only 31 is shown, and in the following, description will be made with these three beams.

Electron beam EB formed by mask 3
11 to EB31 are imaged on the sample 8 by the lenses 5 and 7. 6 is an aperture, 4a and 4b are electron beams EB11
Is a deflector for simultaneously deflecting EB31 and includes deflectors 4a and 4a.
The electron beams EB11 to EB31 are raster-scanned on the sample 8 by b. SE11, SE21 and SE31 are secondary electrons emitted from the irradiation points of the electron beams EB11, EB21 and EB31 of the sample 8 and pass through the lens apertures 901, 902 and 903 of the multi-lens 9. Secondary electrons SE that have passed through the lens apertures 901 to 903
11-SE31 are openings 101- of the multi-aperture plate 10, respectively.
After passing through 103, detectors M11 to M31 such as electron multipliers
Is detected by The multi-lens 9 and the multi-aperture plate 10 are arranged so that the irradiation point of the electron beam EB11, the center of the lens aperture 901 and the center of the aperture 101 are arranged on the same axis J11 when the voltages of the deflectors 4a and 4b are zero. It is configured. Similarly, the lens aperture 902
And the aperture 102 is on the axis J21 and the lens aperture 90
3 and the opening 103 are respectively arranged on the axis J31. Further, the multi-lens 9 and the multi-aperture plate 10 are
It is a plane member whose axis is normal to J21 and is made of a non-magnetic metal such as aluminum or copper. The signals from the detectors M11 to M31 are processed by the signal processing circuit 12, and the comparison circuit 13
The defect is detected by comparing with reference data on the pattern. Reference numeral 14 is a storage unit that stores reference data in advance.

Voltages V9 and V10 (V9 <V10) are applied to the multi-lens 9 and the multi-aperture plate 10, respectively, and the potential of the multi-lens 9 is set higher than that of the sample 8. The voltages V9 and V10 are adjusted so that the sample 8 and the lens apertures 901 to 903 have a conjugate relationship with the secondary electrons having energy of 2 eV. P9 and P10 show the outline of equipotential surfaces near the openings of the multilens 9 and the multi-aperture plate 10, respectively, which are convex toward the sample 8 side. Therefore, the lens apertures 901 to 903 and the opening 10
1 to 103 act as a convex lens for secondary electrons. The lens apertures 901-903 have a larger amount of 2
The opening area is set large so that the secondary electrons can be collected in the detectors M11 to M31, but as described above, the secondary electron is focused at the centers of the openings 101 to 103 because of the convex lens function. The areas of the openings 101 to 103 are smaller than those of the lens apertures 901 to 903.

Thus, from the sample 8 to the multi-aperture plate 10
As the potential increases over time, the lens aperture 9
Since 01 to 903 and the openings 101 to 103 act as a convex lens, the secondary electrons emitted from the sample 8 can be efficiently detected by the detectors M11 to M31. Also,
Since the areas of the openings 101 to 103 are small and distant from each other, for example, the probability that secondary electrons SE21 generated by the adjacent electron beams EB21 are incident on the detectors M11 and M31 is very small, and the S / N ratio is improved. .

Further, the areas of the lens apertures 901 and 903 are set to be larger than the area of the lens aperture 902. FIG. 2A is a diagram for explaining this difference in area, and the electron beam EB11,
6 is an enlarged view of a portion where EB21 and EB31 are incident on the sample 8. FIG. Secondary electrons generated when the sample is irradiated with the electron beam are emitted according to the “cos law”. For example,
When the sample is irradiated with the electron beam vertically, the probability that the electron beam is emitted in the normal direction of the sample is the largest, and the probability decreases as the angle from the normal increases. The secondary electron emission amount is proportional to ω cos θ, where θ is the angle from the sample normal and ω is the solid angle centered on the irradiation point on the sample. In the present embodiment, since the electron beams EB11 to EB31 are obliquely incident on the surface of the sample 8, the axes AX11, AX21, A having a relationship of specular reflection with the incident direction of the electron beams EB11 to EB31.
It has the highest probability of being emitted in the X31 direction.

In FIG. 2A, θ11 is an angle formed by the axes AX11 and J11, θ31 is an angle formed by the axes AX31 and J31, and ω11, ω21 and ω31 are lens apertures 90.
The solid angles are 1,902 and 903. The axis AX
21 and J21 are in agreement. Therefore, the ratio of the amount of secondary electrons incident on each lens aperture 901 to 903 is

[Equation 1] (ω11 · cos θ11): ω21: (ω31 · cos θ31) (1) Therefore, in the present embodiment, the solid angles ω11 and ω31 of the lens apertures 901 and 903 are set to

Equation 2 ω11 = ω21 / cos θ11 (2) ω31 = ω21 / cos θ31 (3) As a result, the amount of secondary electrons incident on the lens apertures 901 and 903, that is, the amount of secondary electrons incident on the detectors M11 and M31, is the same as the amount of secondary electrons incident on the detector M21 arranged in the specular reflection direction. The same degree is achieved and the detection efficiency is improved. Since the amount of secondary electrons incident on the openings 901 to 903 does not always depend only on the angle θ, the solid angles ω11 and ω31 are not limited to the formulas (2) and (3).

When secondary electrons are detected by vertically irradiating a sample with an electron beam, the detector has to be arranged in an oblique direction with respect to the irradiation point. Is smaller, and the amount of secondary electrons that can be detected is smaller. However, in the case of obliquely irradiating the electron beam as in the present embodiment, the space for arranging the detector and the like becomes wider than that in the vertical irradiation, so that a larger number of detectors can be provided, The detector can be placed in or near a direction that satisfies the specular reflection condition. Therefore, as compared with the vertical irradiation, the amount of secondary electrons is increased, the S / N ratio is improved, and the scanning speed can be increased.

FIG. 2B shows 18 electron beams EB11 to EB36 formed on the sample 8 and is a view of the sample 8 seen from the lens 7 side. Reduction ratio of lenses 5 and 7 is 1 /
10, the electron beam EB11 imaged on the sample 8
~ EB36 is 0.1μm square and pitch is 100μ
m. However, since the sample 8 is not perpendicular to the optical axes of the lenses 5 and 7, the dimension in the x-axis direction is exactly 0.1.
Although not μm and 100 μm, here, in order to simplify the explanation, 0.1 μm and 100 μm are considered. Assuming that the deflection amounts of the deflectors 4a and 4b are 100 μm in the x and y directions on the sample 8, respectively, it is 300.1 μm on the sample 8.
An area of m × 600.1 μm square is simultaneously scanned. Then, the sample 8 is moved in the x or y direction and the same scanning is performed. By repeating such scanning, the entire area of the sample 8 can be inspected. In this way, different regions on the sample 8 can be inspected at the same time by a plurality of electron beams EB11 to EB36, so that the inspection time can be greatly shortened as compared with the conventional inspection with one electron beam. can do.

In the present embodiment, since the normal line of the sample 8 is tilted with respect to the optical axes of the lenses 5 and 7, the electron beams EB11 and EB31 at positions apart from the optical axes are blurred. Therefore, as shown in FIG. 2B, the number of beams in the x-axis direction in which the distance between the lens 7 and the sample 8 changes is reduced so that the positional deviation in the z-direction falls within the depth of focus. In addition,
In this embodiment, the electron beams EB11 to EB31 are applied to the sample 8
Although the light is obliquely incident with respect to, the light may be vertically incident. In that case, other effects excluding the effect due to oblique incidence, that is, the inspection time is shortened by using a plurality of electron beams, and the S / N ratio is improved by increasing the size of the lens apertures 901 to 903 toward the periphery. Can be similarly achieved.

-Second Embodiment- FIG. 3 is a diagram for explaining a second embodiment of the defect inspection apparatus according to the present invention. In the apparatus of FIG. 3, the same parts as those of FIG. 1 are designated by the same reference numerals. The secondary electron detection system (multi-lens 9, detectors M11 to M31, etc.), which is the same portion, is omitted because it is unnecessary for the description. As described in the first embodiment, since the electron beams EB11 to EB31 are obliquely applied to the surface of the sample 8, the distance from the lens 7 to the irradiation point of the sample 8 differs depending on the electron beam. . Therefore, in the apparatus of the present embodiment, the object side distance, that is, the distance from the lens 5 to the opening 301a of the mask 301 is set so as to correspond to the image side distance. As a result, the optical path length from the aperture 3a to the surface of the sample 8 becomes equal for all electron beams. FIG.
In the mask 301 of FIG. 3A, the openings 301a are formed in a stepped shape as shown in the figure so that the optical path lengths are equal, while in the case of the mask 302 of FIG. By holding the planar mask 302 obliquely with respect to the lens 5, the optical path lengths are made equal. In the case of the mask 302, when the circular electron beam is to be obtained on the sample 8, the opening 302 is used.
It is sufficient to make a a elliptical shape.

As shown in FIG. 3A, the electron beam EB
11 and EB21, when the difference in the distance from the lens 7 to the sample 8 is Δz, the reduction ratio of the lenses 5 and 7 is 1
If / M, the step between the opening forming the electron beam EB11 and the opening forming the electron beam EB21 is MΔz. That is, if the distance from the lens 7 to the sample 8 is increased by Δz, the distance from the lens 5 to the aperture 301 is M.
Reduce by Δz. The same applies to the case of the mask 302.

As described above, the opening 3 is formed depending on the inclination of the sample 8.
By changing the distance of 01a in the z-axis direction, the focusing condition can be satisfied for all electron beams, and the blurring of the beam on the sample 8 can be suppressed. Further, as shown in FIG. 2B, since the number of electron beams in the y-axis direction is larger than that in the x-axis direction, field curvature of the lens system is likely to occur, but the aperture position is shifted in the z-axis direction. This can be corrected by doing so.

-Third Embodiment- FIG. 4 is a diagram showing a third embodiment of the defect inspection apparatus according to the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. In the apparatus of FIG. 1 described above, the electron beams EB11 to EB
Although the deflectors 4a and 4b for scanning 31 are arranged between the mask 3 and the lens 5, in the apparatus of FIG.
A deflector 15 was provided between the lens 7 and the sample 8 instead of a and 4b. Further, the deflectors 16 are provided corresponding to the secondary electrons that have passed through the lens apertures 901 to 903, respectively. A control circuit 17 controls the deflectors 15 and 16. Other configurations are the same as those of the apparatus shown in FIG.

When the deflector 15 scans the electron beams EB11 to EB31, the electron beam irradiation point position on the sample 8, that is, the secondary electron generation point position changes. As a result, the secondary electrons that have passed through the lens apertures 901 to 903 deviate from the center of the aperture of the multi-aperture plate 10, and the detectors M11 to M11.
The detection efficiency by M31 changes. Therefore, in the present embodiment, the secondary electrons SE11 to SE11 are synchronized with the scanning of the deflector 15.
SE31 is deflected by the deflector 16, and the lens aperture 901
The control circuit 17 controls so that the secondary electrons passing through ˜903 enter the center of the aperture of the multi-aperture plate 10. Therefore, even when the electron beam is scanned, the change in detection efficiency can be reduced.

For example, the applied voltage of the deflector 15 is 0 (V).
Then, the voltage of the deflector 16 at which the output of the detectors M11 to M31 becomes maximum is stored in advance. Further, the voltage of the deflector 16 that maximizes the outputs of the detectors M11 to M31 with respect to the voltage of ± for scanning the electron beam by the deflector 15 is stored in advance. Then, based on these stored data, the deflector 1
The voltage applied to the deflector 6 with respect to the voltage applied to 5 is controlled.

-Fourth Embodiment- FIG. 5 is a diagram showing a fourth embodiment of the defect inspection apparatus according to the present invention. The same parts as those in FIGS. 1 and 4 are designated by the same reference numerals. , The different parts will be mainly described. Reference numeral 18 denotes a multi-lens having lens apertures 181, 182 and 183, and 19 denotes a multi-aperture plate having openings 191, 192 and 193, which correspond to the multi-lens 9 and the multi-aperture plate 10 of the apparatus shown in FIG. However, multi-lens 9
The multi-aperture plate 10 is a flat member, and the detector M
11 to M31 are also arranged on a plane, but the multi-lens 18 and the multi-aperture plate 19 form a part of a spherical shell centered on the irradiation point of the electron beam EB21 on the sample 8, and the detector M
11 to M31 are also arranged on a spherical surface centered on the irradiation point of the electron beam EB21. Further, the openings 191, 192, 193 of the multi-opening plate 19 are formed at positions displaced from the axes J11, J21, J31. Therefore, the multi-lens 18
The electron beams EB11, EB21, and EB31 that have passed through are respectively deflected by the deflector 16 so that the aperture 191,
It is incident on the centers of 192 and 193.

Further, in the apparatus of FIGS. 1 and 4, since the lens apertures 901 to 903 are arranged on the plane, the lens aperture 901 is located farther from the sample 8 than the lens aperture 903, and as a result, the lens The aperture area of the aperture 901 is closer to the lens aperture 903.
Get bigger. However, in the apparatus of FIG. 5, since the lens apertures 181 to 183 are arranged on the spherical surface centered on the irradiation point of the electron beam EB21, the lens aperture 1
The opening areas of 81 and 183 are almost equal.

A shield 20 is provided between the multi-lens 18 and the deflector 16, and the shield 20 has a secondary electron S.
Apertures 201 and 2 for passing E11, SE21 and SE31
02 and 203 are formed. The shield 20 is formed of a non-magnetic metal like the multi-lens 18 and the multi-aperture plate 19 and forms a part of a spherical shell centered on the irradiation point of the electron beam EB21 and shields the electric field of the deflector 16. The lens performance of the multi-lens 18 is not affected. Other configurations are similar to those of the apparatus shown in FIGS.

In the present embodiment, since the multi-lens 18 and the multi-aperture plate 19 are spherical shells having the electron beam incident point as a common center, they are formed between the multi-lens 18 and the multi-aperture plate 19. The equipotential surface of the electric field is also a concentric spherical surface, and aberration due to the electric field does not occur, so that secondary electrons can be efficiently detected. The secondary electron SE11
~ SE31 is the lens aperture 181 of the multi-lens 18
To 183, i.e., it is vertically incident on the lens surface of the multi-lens 18.
The aberration due to can be reduced. Further, since the electric field of the deflector 16 is shielded by the shield 20, it is possible to eliminate the influence of the lens apertures 181 to 183 on the electric field and reduce the aberration of the multi-lens 18.

When performing a defect inspection, there are cases where it is better to detect secondary electrons and cases where it is better to detect reflected electrons of the electron beam with which the sample is irradiated. In the device of the present embodiment, the openings 191 to 193 are connected to the axes J11 to J31.
The secondary electron SE is
When 11-SE31 are guided to the centers of the openings 191-193, respectively, backscattered electrons having low deflection sensitivity travel in the directions of the axes J11-J31 and do not enter the openings 191-193. That is, when detecting the secondary electrons, the reflected electrons are not detected as described above, while when the reflected electrons are detected, the reflected electrons are incident on the openings 191 to 193 of the deflector. It is sufficient to deflect the voltage.

In the above embodiment, the electron beam EB
11-EB31 are explained, but other electron beam E
The same applies to B12 to EB36. Although the electron beam has been described as the charged particle beam, the present invention is not limited to the electron beam and can be applied.

In the correspondence between the above-described embodiment and the elements described in the claims, the mask 3 is a beam forming means, and the polarizers 4a, 4b and 15 are charged particle beam polarizers.
The control circuit 17 constitutes a control means, the multi-lenses 9 and 18 constitute a multi-electron lens device, the deflector 16 constitutes an electronic deflector, and the lens apertures 901 to 903 and 181 to 183 constitute electron lenses. Further, the detectors M11 to M31 form a multi-detection device.

[0030]

As described above, according to the present invention,
Since different regions on the sample can be inspected at the same time by a plurality of charged particle beams, the inspection time can be greatly shortened without lowering the inspection accuracy. According to the invention of claim 3, since the charged particle beam is radiated obliquely to the sample surface, the space for arranging the detectors can be increased, and a larger number of detectors can be provided. . Also,
Since the detector is provided on or near the axis that satisfies the specular reflection condition with respect to the incident axis of the charged particle beam, the detection efficiency of electrons from the sample surface is improved and the S / N ratio is improved. According to the inventions of claims 4 and 5, blurring of the image of the charged particle beam with which the sample is irradiated can be reduced, and the detection sensitivity is improved. According to the inventions of claims 7 and 8, the electrons from the sample surface are focused by the lens aperture and enter the detector, so that the electron detection efficiency is improved and the S / N ratio is improved. According to the invention of claim 9, the larger the angle formed by the axis that satisfies the specular reflection condition and the axis that passes through the charged particle beam irradiation point and the center of the lens aperture, the larger the aperture area of the lens aperture becomes. The electron detection amount is substantially the same regardless of the arrangement position of the, and the difference in the detection amount depending on the detection direction can be reduced. According to the tenth aspect of the invention, even if the irradiation position of the charged particle beam is changed by the scanning of the charged particle beam, the electron is deflected by the electron deflector so that the electron always enters the detector, so that the electron detection efficiency changes. Can be reduced. According to the invention of claim 11, since the influence of the electronic deflector on the lens aperture is reduced by the shield, the lens aberration of the lens aperture can be reduced. According to the invention of claim 12, the number of blurred charged particle beams on the sample can be reduced even when a larger number of charged particle beams are used.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of a defect inspection apparatus according to the present invention, and is a schematic configuration diagram of the apparatus.

2A and 2B are diagrams illustrating secondary electrons emitted from a sample and a scanning region on the sample, FIG. 2A is an enlarged view of an electron beam irradiation portion on the sample, and FIG. 2B is an image formed on the sample. It is a figure which shows the electron beam which carried out.

FIG. 3 is a diagram illustrating a second embodiment of the defect inspection apparatus according to the present invention.

FIG. 4 is a diagram illustrating a third embodiment of the defect inspection apparatus according to the present invention.

FIG. 5 is a diagram illustrating a fourth embodiment of the defect inspection apparatus according to the present invention.

[Explanation of symbols]

1 Electron Gun 3 Mask 3a, 101-103, 191-193, 201-20
3 Apertures 4a, 4b, 15, 16 Deflectors 5, 7 Lenses 8 Samples 9, 18 Multi-lenses 10, 19 Multi-aperture plate 11 Holding table 12 Signal processing circuit 13 Comparison circuit 14 Storage section 17 Control circuits 901-903, 181- 183 lens aperture EB11 to EB36 electron beam M11 to M13 detector SE11 to SE31 secondary electron

Claims (12)

[Claims] 1. A defect inspection apparatus characterized by scanning a plurality of charged particle beams on a sample and detecting electrons from the sample for each charged particle beam to inspect a pattern for defects on the sample. 2. A beam forming a plurality of charged particle beams in a defect inspection apparatus for detecting a defect of the pattern by irradiating a sample on which a pattern is formed with a charged particle beam and detecting electrons from the sample. Forming means, a charged particle beam deflector for simultaneously scanning each of the charged particle beams on a corresponding region of a plurality of regions provided on the sample, and a detector for detecting electrons from the sample, respectively. A defect inspection apparatus comprising: a multi-detection device; and a multi-electron lens device having a plurality of electron lenses that respectively guide electrons from the sample to the detector. 3. The defect inspection apparatus according to claim 1, wherein the charged particle beam is incident on the sample surface while the incident direction of the charged particle beam on the sample is different from the normal direction of the sample surface. The defect inspection apparatus is characterized in that the detectors are respectively provided on or near an axis satisfying a specular reflection condition with respect to the incident axis of. 4. The defect inspection apparatus according to claim 3, wherein the beam forming means is a substrate having a plurality of holes, and the optical path lengths of the charged particle beam from the plurality of holes to the sample surface are all equal. In this way, the defect inspection apparatus is characterized in that the positions of the plurality of holes in the optical axis direction are shifted. 5. The defect inspection apparatus according to claim 3, wherein the beam forming unit has a substrate having a plurality of holes and a holding table for holding the substrate, and the beam from the plurality of holes is the sample surface. The defect inspection apparatus is configured to hold the substrate while inclining the substrate with respect to the sample surface so that the optical path lengths of the charged particle beams up to are equal to each other. 6. The defect inspection apparatus according to claim 1, wherein the plurality of electron lenses are respectively arranged on a first spherical surface centered on a charged particle irradiation point on the sample, A defect inspection apparatus characterized in that a plurality of detectors are arranged on a second spherical surface that is concentric with the first spherical surface and has a radius larger than the first spherical surface. 7. The defect inspection apparatus according to claim 1, wherein the plurality of electron lenses are a plurality of lens apertures formed on a nonmagnetic metal plate to which a first potential is applied. ,
A second electric potential higher than the first electric potential is applied between the plurality of lens apertures and the plurality of detectors, and electrons in a predetermined region among the electrons that have passed through the respective lens apertures are detected by the detectors. A defect inspection apparatus comprising a multi-aperture plate for leading to a defect. 8. The defect inspection apparatus according to claim 7, wherein the plurality of lens apertures are respectively arranged on a first spherical surface having a charged particle irradiation point on the sample as a center and are formed on the multi-aperture plate. The plurality of apertures are arranged on a second spherical surface concentric with the first spherical surface and having a radius larger than the first spherical surface, and the plurality of detectors are arranged on the second spherical surface.
And a third spherical surface that is concentric with the spherical surface and has a radius larger than that of the second spherical surface. 9. The defect inspection apparatus according to claim 8, wherein an axis that satisfies a specular reflection condition with respect to an incident axis of a charged particle beam incident on the sample surface, a charged particle beam irradiation point on the sample, and the A defect inspection apparatus characterized in that the opening area of the lens aperture is increased as the angle formed by the axis passing through the center of the lens aperture increases. 10. The defect inspection apparatus according to claim 1, wherein an electron deflector that deflects each electron passing through the multi-electron lens device, and each electron in each of the detectors. A defect inspection apparatus, comprising: a control unit that controls the electron deflector in synchronization with the deflection of the charged particle beam deflector so as to be incident. 11. The defect inspection apparatus according to claim 10, wherein a shield for shielding an electric field of the electron deflector is provided between the electron lens device and the electron deflector. apparatus. 12. The defect inspection apparatus according to claim 2, wherein the array distribution of the plurality of charged particle beams formed by the beam forming means has a change in optical path length to the irradiation surface of the sample. Defect inspection, characterized in that the number of charged particle beams imaged in a first direction is smaller than the number of charged particle beams imaged in a second direction orthogonal to the first direction. apparatus.