JP2003297278A - Inspection apparatus and inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection apparatus and an inspection method for making inspection by irradiating a sample with an electron beam, by which image formation is achieved with good quality without need of any complicated optical system, and throughput of inspection can be improved. <P>SOLUTION: The electron beam inspection apparatus 35 is equipped with 2 sources 21a, 21b of electron beam, and 4 electron beams 2A-2D are emitted from each source 21 of electron beam. Pairs of corresponding electron beams from the 2 sources 21a, 21b of electron beam are struck on prescribed positions of a surface of a sample 10, respectively. The electron beams 2A-2D are scanned in corresponding regions 91A-92B in charge on the surface of the sample 10, thereby covering the whole area 90 to be irradiated. An image of electrons from the surface of the sample 10 is formed in a detecting section 14 by a mapping projection section 25. A signal outputted on the basis of this image formation is processed in a image processing section 30. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and an inspection method for inspecting a surface of a solid sample by using an electron beam, and more particularly, to detect a defective wafer or a semiconductor by inspecting a pattern of a semiconductor wafer or a photomask. The present invention relates to an inspection device and an inspection method useful for improving process yield.

[0002]

2. Description of the Related Art An inspection apparatus for irradiating a solid sample such as a semiconductor wafer with an electron beam for inspection is known. Conventionally, in such an inspection apparatus, a single electron beam is emitted from a single electron beam source. In this case, when the electron beam is irradiated obliquely to the sample surface and the electron beam is taken out from the direction perpendicular to the sample surface, there is a problem that unevenness on the sample surface causes a shadow, so in the conventional inspection apparatus,
An electron beam in an oblique direction is deflected by a Wien filter (E × B filter) so as to be incident in a direction perpendicular to the sample surface, and electrons from the sample are the strength of the electric field and magnetic field of the Wien filter. Depending on the setting, the sample surface was taken out without being deflected in the vertical direction.

FIG. 11 shows a mapping projection type electron beam inspection apparatus 34 which is an example of such a conventional inspection apparatus. The inspection device 34 includes an electron gun 1 for irradiating a sample 10 with a primary electron beam 2 and a detector 1 for detecting secondary electrons 11 generated from the sample surface by irradiation with the primary electron beam 2 and generating an image signal.
4, a Wien filter 5 having an electrode 6 and a magnet 7, a first lens system 3 and a second lens system 4 for molding the primary electron beam 2, and a third lens system 8 arranged between the Wien filter 5 and the sample 10. And a fourth lens system 9, a sixth lens system 12 and a seventh lens system 13 arranged between the Wien filter 5 and the detection unit 14. In this inspection device,
The electron beam 2 emitted from the electron gun 1 by the Vienna filter 5
Is set so that the irradiation electron beam 2 is vertically incident on the sample surface, while the secondary electrons 11 emitted from the sample surface go straight and reach the detection unit 14. Such a detecting device is disclosed in, for example, Japanese Patent Laid-Open No. 11-13975.
It is disclosed in the publication.

[0004]

However, since such a conventional inspection apparatus uses the Wien filter, the transmittance of electrons from the sample is deteriorated, and aberrations such as distortion aberration are large, resulting in a blurred image field. There was a problem such as poor resolution at the periphery. In addition, there is a problem that a magnetic field is used in the Wien filter, a magnetic shield for the electron optical system is required, and a lens barrel shape becomes large.

Further, since only one electron beam is extracted from one electron beam source and is applied to the illumination area of the sample all at once, the illumination area is easily charged (charge-up). There is a problem that the image is distorted or out of focus because the imaging failure is caused in the next optical system. Further, in order to perform uniform illumination with one electron beam, a complicated illumination optical system is required. Furthermore, the amount of current obtained is small, and the throughput (the number of samples that can be processed in a unit time, for example, one sheet / hour). ) Was low.

The present invention has been made in view of such problems, and an inspection apparatus and an inspection method for inspecting by irradiating a sample with an electron beam do not require a complicated optical system and are of high quality. It is an object of the present invention to provide an image-capturing device that can improve imaging throughput.

[0007]

According to a first aspect of the present invention, there is provided an inspection apparatus for inspecting a state of a sample surface by irradiating the sample with an electron beam and detecting electrons generated from the surface of the sample. An electron that is provided with a plurality of electron beam sources for irradiating, outputs a plurality of electron beams from each electron beam source, and irradiates corresponding electron beams from different electron beam sources to substantially the same location on the sample surface. A radiation source, a scanning means for scanning the electron beam from these electron beam sources on the sample surface so that the entire irradiation area of the sample surface is irradiated with the electron beam, and the sample surface irradiated with the electron beam The image projection unit for forming an image of the electrons on the detection unit and the image processing unit for processing the signal output based on the image formation by the image projection unit.

According to a second aspect of the present invention, a sample moving means for moving the sample is provided, and the entire inspection area on the sample surface is irradiated with the electron beam by the scanning by the scanning means and the movement of the sample by the sample moving means. I chose

According to a third aspect of the invention, the image processing section is
Abnormalities on the sample surface are detected by comparing images at a plurality of irradiation locations. In the invention of claim 4, the plurality of electron beam sources are installed at positions that are rotationally symmetric with respect to the central axis of the image projection unit and are evenly divided.

According to a fifth aspect of the invention, in the first to fourth aspects of the invention, the sample is a semiconductor wafer in the process of being processed. According to the invention of claim 6, in the inspection method for inspecting the state of the sample surface by irradiating the sample with an electron beam and detecting electrons generated from the sample surface, a plurality of electron beams are emitted from each of the plurality of electron beam sources. By outputting and outputting corresponding electron beams from different electron beam sources to almost the same place on the sample surface, and scanning of these electron beams on the sample surface and movement of the sample, the entire inspection area of the sample surface Is irradiated with an electron beam, and a step of forming an image of electrons from the sample surface irradiated with the electron beam on the detection unit,
And a step of processing a signal based on the image formation.

According to the invention of claim 7, in the invention of claim 6, the sample is a semiconductor wafer in the process.

[0012]

According to the inspection apparatus or the inspection method of the present invention, since a set of electron beams is irradiated to substantially the same place on the sample surface from different directions, it is possible to prevent the generation of shadows due to the unevenness of the sample surface. Can be prevented. Therefore, it is not necessary to use the Wien filter, and it is possible to avoid the problems that the Wien filter increases aberrations and blurs the image, requires a magnetic shield, and enlarges the lens barrel. Further, a plurality of electron beams are emitted from each of the plurality of electron beam sources, and the entire inspection area is covered by scanning these electron beams and moving the sample. For this reason, the area irradiated with each electron beam can be reduced, so that the imaging failure due to charge-up of the sample is reduced. Further, since the amount of irradiation electron beam at each irradiation position can be increased, an image with higher contrast can be obtained. Further, by scanning with an electron beam, it is possible to easily and uniformly irradiate the entire irradiation area.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the first of the present invention.
It is a block diagram showing composition of an electron beam inspection device in an embodiment. As shown, the electron beam inspection device 35
Two electron beam sources 21 that irradiate the sample 10 such as a silicon wafer with the electron beam 2, and a mapping projection unit 25 that forms an image of the secondary electrons 11 from the sample surface irradiated with the electron beam on the detection unit 14.
A signal detecting unit 14 that detects and outputs the electronic signal formed by the image projecting unit 25; and an image processing unit 30 that displays the signal output from the signal detecting unit 14.

Two electron beam sources 21 (21a and 2a in FIG. 1)
1b) is a plurality (4 in the present embodiment).
Equipped with electron guns. Thereby, each electron beam source 2
As shown in FIG. 2, four electron beams 2 (indicated by 2A, 2B, 2C, and 2D in FIG. 2) from the No. 1 are deflected electrodes 22.
It is emitted from between. Corresponding electron beams 2 from the two electron beam sources 21 (in this case, for example, the electron beam 2A of one electron beam source 21 corresponds to the electron beam 2A of the other electron beam source 21, and similarly the electron beam 2B). Corresponds to the electron beam 2B, the electron beam 2C corresponds to the electron beam 2C, and the electron beam 2D corresponds to the electron beam 2D) are applied to substantially the same location P on the surface of the sample 10 from different directions, and the unevenness of the sample surface causes No shading is created on the image.

However, as will be described later in detail, when the beam scanning is performed at a speed sufficiently higher than the integrated speed of the detection unit, the corresponding electron beams (for example, 2A) do not necessarily move to the same location at the same time. No need to irradiate. That is, the electron beams 2A, 2B, 2C, and 2D are beam-scanned within their respective areas 91A, 91B, 91C, and 91D (see FIG. 4), but the electron beam source 21a
Corresponding to the electron beams 2A to 2D from the electron beams 2A to 2D from the electron beam source 21b (for example, the electron beam source 21
Electron beam 2A from a and electron beam 2A from electron beam source 21b
Etc.) are not necessarily in their respective areas 91A, 91A
It is not necessary to irradiate the same position in B, 91C, and 91D.

FIG. 3A is a sectional view showing a shadow 31 generated by the convex portion 32 on the sample surface, and FIG. 3B is a sectional view showing the arrangement of the electron beam 2 for preventing the generation of the shadow. Figure 3
As shown in (A), when an electron beam is incident on the surface of a sample having a convex portion 32 from one side of the convex portion, a shadow 31 without electron beam irradiation is generated on the other side of the convex portion. In order to prevent the generation of such a shadow, conventionally, an electron beam was deflected by a Wien filter and made incident on the sample surface in a vertical direction, so there was a problem caused by the Wien filter as described above. Therefore, instead of using the Wien filter, as shown in FIG. 3B, the other side of the convex portion is irradiated with another electron beam to generate the shadow 31 due to the convex portion in FIG. Prevent. Thereby, even when the sample surface has a concave portion, the electron beam is incident from both sides of the concave portion, so that the shadow due to the concave portion can be prevented.

More specifically, in the electron beam inspection apparatus 35 of FIG. 1, the two electron beam sources 21 and 21 are the center lines of the image projection unit 25, that is, the irradiation units P of the electron beams 2A to 2D and 2A to 2D. They are arranged symmetrically with respect to a line perpendicular to the sample surface (the same as the electron beam 11 generated from the sample surface).
In the present embodiment, the electron beams 2A to 2D and 2A to 2D are used.
The incident angle of is 45 degrees. However, if structurally possible, this incident angle is not limited, for example, 20 degrees to 7 degrees.
It can be any angle of 0 degrees.

With such a configuration, the electron beam inspection apparatus 3
5, the electron beams 2A and 2A from the two electron beam sources 21 and 21 are 2A, 2A, 2C and 2C, 2C and 2C, and 2
The set of D and 2D is irradiated from different directions to different predetermined points P on the surface of the sample 10. The images obtained by irradiation from the different directions are collectively detected. It is also possible to construct a three-dimensional image of the image by comparing the images independently acquired with respect to the electron beam irradiation in a specific direction, from the difference in the shadows in the respective irradiation directions.

FIG. 4 shows a sample 1 of primary electron beams 2A to 2D.
The scanning method on 0 is shown. The irradiation area 90 is an area where an image is to be observed or a slightly larger area, and a plurality of (four in the present embodiment) responsible areas 91.
It consists of A to 91D. The areas in charge 91A to 91D are
These are areas to be illuminated by the primary electron beams 2A to 2D, respectively.

The irradiation spots 92A to 92D which the electron beams 2A to 2D irradiate at a time are areas narrower than the areas 91A to 91D in charge to be irradiated by the electron beams 2A to 2D, but the electron beams 2A to 2D. Are scanned on the surface of the sample 10 so that the electron beams 2A to 2D are irradiated over the respective areas 91A to 91D in charge. As a result, the irradiation of the electron beam is controlled by the area 91A in charge.
To the entire irradiation area 90, which is an area obtained by combining .about.91D.

For example, by scanning an irradiation spot, which is an elliptical or circular small region, on the sample surface, the entire elliptical or rectangular area in charge (as a result, the entire irradiation area) is covered. Thereby, the charge-up of the sample 10 due to irradiation can be effectively prevented. Furthermore, by combining the movement of the stage, uniform irradiation can be easily performed over the entire inspection area (the area where the inspection is to be performed).

Specifically, for example, the irradiation spots 92A to 92D of the electron beams 2A to 2D are φ1.0 μm to φ10 μ.
The irradiation area is a circle of m, and the irradiation area covered by the scanning of the electron beams 2A to 2D is a rectangle of 210 μm × 52 μm. Four electron beams 2A from each electron beam source 21a, 21b
The irradiation current of ~ 2D is 100 nA (800 total).
nA), the electron acceleration voltage is −4.5 kV, and the sample bias voltage is −4 kV. Since the irradiation energy of the electron beam to the sample is 0.5 keV, damage to the sample due to the electron beam is reduced. The shape of the irradiation spot is not limited to a circular shape, and may be an ellipse, for example.

Scanning of the electron beams 2A to 2D (irradiation spots 92A to 92D) in the areas in charge 91A to 91D is relatively fast in the long side direction (X direction) of the irradiation area 90 as shown in FIG. 4, for example. And a relatively slow scan in the short side direction (Y direction) (so-called raster scan) are combined (for example, see the description of FIG. 10). It should be noted that the scanning method in each area in charge is not particularly limited, and any method can be adopted as long as it can uniformly irradiate the entire area in charge with an electron beam. Specifically, for example, the scanning in each area is performed by a combination of relatively high speed scanning in the short side (Y direction) and relatively low speed scanning in the long side (X direction). Alternatively, the scanning may be performed along the Lissajous figure. Further, the form of dividing the irradiation area 90 into the areas in charge is not particularly limited, and any form can be adopted.

The image projection unit 25 includes a two-stage electrostatic lens system 2
6, 28 and diaphragm 27. The detection unit 14 includes a micro channel plate (MCP), a fluorescent screen, a fiber optical plate (FOP), and a line type image sensor (TDI-CCD camera) which are not shown.

The sample 10 is mounted on the XY electrostatic stage 29, continuously moved at a speed commensurate with the imaging magnification, and a continuous image is obtained in combination with the line sensor. The position of the XY stage is monitored by a laser interferometer and controlled with accuracy on the order of nm.

The image processing section 30 displays the electric signal from the detection section 14 as an image on the CRT, and also displays a specific portion.
It is equipped with a function to detect abnormalities by comparing the above images.
The number of pixels of the TDI-CCD camera (not shown) incorporated in the detection unit 14 is 2048 stages and 32 taps, the signal processing speed is 800 MHz, and the effective processing speed is 60.
0 MHz is obtained. According to this embodiment, a visual field of 200 μm and a resolution of 0.1 μm were obtained when the magnification of the image projection unit was 160 times.

FIG. 5 is a block diagram showing the arrangement of an electron beam inspection apparatus according to the second embodiment of the present invention. In the present embodiment, the electron beam inspection device 36 includes four electron beam sources 2
1a, 21b, 21c, 21d. These electron beam sources 21a, 21b, 21c, and 21d are arranged in rotational symmetry every 90 degrees with respect to a center line of the image projection unit, that is, a straight line that passes through the center of the elliptical or rectangular irradiation area and is perpendicular to the paper surface. To be done.

The irradiation conditions of the electron beam sources 21a to 21d are as follows.
This is almost the same as in the case of the first embodiment. That is, four electron beams 2A are emitted from each of the electron beam sources 21a to 21d.
˜2D is irradiated, and the scanning of these electron beams 2A to 2D covers the entire irradiation area. Each electron beam 2A ~
The incident angle with respect to the sample surface of 2D is 45 degrees, the irradiation spot is a circle of φ1.0 μm to φ10 μm, and the irradiation area (total irradiation area by scanning) is a rectangle of 220 μm × 55 μm. Electron beam 2A from each electron beam source 21a-21d
The total irradiation current of 2D is 400 nA on the surface of the sample (the total current of the four irradiation parts is 1.6 μA), and the electron acceleration voltage is −4.5 kV.

In the electron beam inspection device 36, the irradiation unit 2
The irradiation portions 21c and 21d are connected to the irradiation portions 21a and 21b so that the irradiation shape substantially similar to the rectangular shape of 1a and 21b can be obtained.
It is rotated by 90 degrees.

The scanning direction 33 of the stage on which the sample 10 is mounted is set to the rectangular short axis of the irradiation electron beam. The electron beam inspection apparatus 36 can provide an image having a higher contrast and less shadows of the unevenness of the sample as compared with the electron beam inspection apparatus 35 shown in FIG. 1, and the throughput can be doubled. .

FIG. 6 is a flow chart showing an example of a semiconductor device manufacturing method using the electron beam inspection apparatus of the present invention. The semiconductor device manufacturing method of FIG. 6 includes the following main steps. (1) A wafer manufacturing process 51 for manufacturing the wafer 52 or a wafer preparation process for preparing the wafer 52. (2) A mask manufacturing process 61 for manufacturing a mask (reticle) 62 used for exposure or a mask preparation process for preparing a mask. (3) Wafer processing step 53 for performing necessary processing on the wafer. (4) A chip assembling step 54 in which the chips formed on the wafer are cut out one by one and made operable. (5) Chip inspection step 56 for inspecting the completed chip 55
And a step of obtaining a product (semiconductor device) 56 consisting of chips that have passed the inspection.

Each of these main steps includes several sub steps. The right part of FIG. 6 shows a sub-process of the wafer processing process 53. Among the main steps (1) to (6), the main step that has a decisive influence on the performance of the semiconductor device is the wafer processing step 53. In this step, the designed circuit patterns are sequentially laminated on the wafer to form a large number of chips that operate as memories and MPUs.

This wafer processing step includes the following steps. (6) Thin film forming step (CV) for forming a dielectric thin film to be an insulating layer, a wiring part, or a metal thin film for forming an electrode part
D or sputtering is used). (7) Oxidation step 6 for oxidizing the thin film layer and the wafer substrate
4. (8) A lithographic process 63 for forming a resist pattern using a mask (reticle) for selectively processing a thin film layer, a wafer substrate, or the like. (9) Etching process 64 (for example, using a dry etching technique) for processing a thin film layer or a substrate according to a resist pattern. (10) Ion / impurity implantation diffusion step 64. (11) Resist stripping step. (12) Inspecting step 65 for inspecting the processed wafer.

The wafer processing step is repeated by the required number of layers to manufacture a semiconductor device that operates as designed. The flowchart of FIG. 6 is based on the above (6),
(7), (9) and (10) are collectively shown in one block 64, including additional washing steps, and the repeating steps are shown in block 66. By using the inspection apparatus of the present invention in the inspection step of inspecting the processed wafer of (12) above, even a semiconductor device having a fine pattern can be inspected at a high throughput, a product yield is improved, and a defective product is produced. It is possible to prevent the shipment.

FIG. 7 is a flow chart showing details of the lithographic process 63 in the manufacturing method of FIG. As shown in FIG. 8, the lithographic process 63 includes (13) a resist coating process 71 for coating a resist on the wafer on which the circuit pattern has been formed in the previous process, and (14) an exposure process 72 for exposing the resist, 15) a developing step 73 for developing the exposed resist to obtain a resist pattern, and (16) an annealing step 74 for stabilizing the developed resist pattern. Since the semiconductor device manufacturing process, the wafer processing process, and the lithographic process are well known, further description will be omitted.

FIG. 8 is a block diagram showing the arrangement of an electron beam inspection apparatus 37 according to the third embodiment of the present invention. Figure 8
The electron beam inspection device 37 of FIG. 1 has a structure in which two electron beam inspection devices 35 of FIG. 1 are combined, and different points P1 and P2 of one sample 10 are controlled by a plurality of electron beam sources 21 of each electron beam inspection device 35. Simultaneously irradiating, the electrons generated by the irradiation points P1 and P2 are imaged on the detecting unit 14 by the respective image projecting units 25, converted into electronic signals by the detecting units 14 and output, and the output signals are not shown in image processing. To be displayed on the image. The same members as those of the electron beam inspection apparatus 35 of FIG. 1 are designated by the same reference numerals, and the duplicate description will be omitted.

This electron beam inspection apparatus 37 has one sample 1
With respect to 0, irradiation is performed on different points for each set of a plurality of electron beam sources 21, so that throughput can be improved by simultaneously inspecting a plurality of points.

In this embodiment, the electron beam inspection device 37 is provided with two sets (four) of electron beam inspection devices 35, but the present invention is not limited to such a form.
The electron beam inspection device 37 may include three or more sets (six or more even number) of the electron beam inspection devices 35. Thereby, the throughput can be further improved.

FIG. 9 shows a fourth embodiment of the present invention.
The electron beam inspection apparatus 100 according to the present embodiment includes an electron beam source 121.
a and 121b. Each electron beam source 121a, 12
From the electron gun 101 of 1b, four electron beams 102A, 1
02B, 102C, 102D are irradiated. Electron beam 10
2A to 102D are shaped by the aperture stop 103, and further, on the sample by the two-stage lenses 104 and 105.
The image is formed into an elliptical shape of 0 μm × 2.4 μm. This statue is
Raster scanning is performed by the deflector 107, whereby four electron beams 102A to 102D are converted into, for example, the sample 1
Irradiation and projection are performed so as to cover a rectangular area of 200 μm × 50 μm on the surface 10.

By this irradiation, 4 × 2 secondary electron beams 112 having information on the sample image 111 are emitted from the sample 110. The secondary electron beam 112 is transmitted through the lenses 109, 1
13 and 114 are enlarged, and 4 of 2 on MCP115
As a combination of images by the next electron beam 112, a rectangular enlarged projection image 116 is formed. This enlarged projection image 116 is an MCP
After being sensitized 10,000 times at 116, it is converted into light by the fluorescent part and further becomes an electric signal synchronized with the continuous moving speed of the sample 110 by the TDI-CCD 117. This electric signal is acquired as a continuous image on the image display unit 118,
It is output to a CRT or the like.

Although not shown in the drawings, the electron beam inspection apparatus according to the present embodiment includes a lens, a limited field stop, and a deflection having four or more poles for adjusting the electron beam axis. It is equipped with a unit necessary for illumination / imaging such as an aligner, an astigmatism corrector (stigmator), and a plurality of quadrupole lenses (quadrupole lenses) for shaping the beam shape.

FIG. 10 is a diagram showing a scanning method of the primary electron beam in this embodiment. It should be noted that in FIG. 10, the irradiation spots 152A to
Two pieces of 152D are shown, but for convenience of description, this shows that the irradiation spots 152A to 152D of the same electron beams 102A to 102D irradiate different points, and two electron beams are included. It does not indicate that is being irradiated.

Explaining in detail, the irradiation area 150 is
The four charge areas 151A to 151D corresponding to the electron beams 102A to 102D from the electron beam source 101 are combined so as not to overlap each other. Irradiation area 150
Is a rectangular area of 200 μm × 50 μm, and the areas 151 A to 151 D in charge are, for example, 200 μm × 12.
It is a rectangular area of 5 μm. The irradiation spots 152A to 152D of the respective electron beams 102 have an elliptical shape of 2 μm × 2.4 μm. This elliptical irradiation spots 152A to 152D
Scans each area 151A to 151
D is covered.

The irradiation spots 152A to 152D of the electron beams 102A to 102D are assigned to the areas 151A to 151 in charge.
The start point at the upper left end of D is reached to the end point at the upper right end (from the position shown on the left side of FIG. 10 to the position shown on the right side of FIG. 10) in the X direction in a finite time. Then, the areas in charge 151A to 1
Irradiation spots 152A to 152 from the start point of the left end of 51D
It returns to the position just below the diameter of D with almost no time loss, and the returned position is used as a new starting point, and X is again used.
Repeat scanning in the direction. When irradiation is performed on the entire areas 151A to 151D in charge by such scanning, the scanning is returned to the starting point at the upper left end again, and similar scanning is repeated at high speed.
In this case, if the scanning position is moved in the Y direction by the XY stage, the movement by the XY stage is made in the direction of arrow 160 in the figure. It should be noted that the moving direction of the XY stage only needs to match the direction of the number of stages of the TDI-CCD (integral direction), and does not have to depend on the scanning direction of the electron beam.

As described above, since the irradiation of the primary electron beam onto the sample 110 is performed by scanning the plurality of primary electron beams 102A to 102D, the irradiation area of a desired shape on the sample 110 is reduced in the irradiation unevenness. It is possible to uniformly irradiate, and high throughput can be obtained. Further, since the irradiation to the irradiation area is the irradiation by scanning the electron beams 102A to 102D, compared with the case where the entire image observation area is collectively irradiated, the imaging obstacle due to the charge-up can be significantly reduced.

Specifically, according to the electron beam inspection apparatus of this embodiment, the electron beam irradiation unevenness could be set to about ± 3%. Also,
Irradiation current is 250 nA per electron beam, 4 × 2
With the electron beam of the book, it was possible to obtain a value of 2.0 μA, which is almost four times the conventional value. If the number of electron beams is increased, the current can be increased and the throughput can be increased.
Further, the irradiation spot can be made smaller (about 1/80 in area) than the conventional one, and since it is moving, the charge-up can be suppressed to 1/20 or less of the conventional one.

In the above description, the scanning was performed by raster scanning, but the scanning method is not limited to raster scanning, and other scanning methods may be adopted. For example, scanning may be performed so as to draw a Lissajous figure.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electron beam inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing how four electron beams are emitted from an electron beam source.

FIG. 3A is a cross-sectional view showing a shadow due to a convex portion on the sample surface, and FIG. 3B is a cross-sectional view showing an arrangement of electron beams for preventing the generation of the shadow.

FIG. 4 is a diagram showing an electron beam scanning method.

FIG. 5 is a block diagram showing an electron beam inspection apparatus according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing an example of a semiconductor device manufacturing method.

7 is a flowchart showing details of a lithographic process in the manufacturing method of FIG.

FIG. 8 is a block diagram showing an electron beam inspection apparatus according to a third embodiment of the present invention.

FIG. 9 is a diagram showing an electron beam apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing an electron beam scanning method.

FIG. 11 is a block configuration diagram showing a conventional electron beam inspection apparatus.

[Explanation of symbols]

2A, 2B, 2C, 2D electron beam 10 samples 14 Detector 21 electron beam source 21a, 21b, 21c, 21d electron beam source 25 Mapping Projector 29 XY electrostatic stage 30 Image processing unit 35, 36, 37 Electron beam inspection device 90 irradiation area 91A, 91B, 91C, 91D Area in charge 92A, 92B, 92C, 92D irradiation spot

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01J 37/28 H01J 37/28 B 5F056 H01L 21/027 H01L 21/66 J 21/66 21/30 541B 541E F term (reference) 2H095 BD02 BD14 BD24 4M106 AA01 BA02 CA39 DB05 DJ04 DJ11 DJ23 5C001 AA03 CC04 5C030 BB17 5C033 UU01 UU03 UU05 5F056 AA33 BA08 CC04

Claims (7)

[Claims] 1. An inspection apparatus for inspecting the state of a sample surface by irradiating a sample with an electron beam and detecting electrons generated from the surface of the sample, comprising: a plurality of electron beam sources for irradiating the sample with electron beams; A plurality of electron beams are output from the electron beam source, and the electron beam sources from which different electron beam sources from different electron beam sources irradiate approximately the same location on the sample surface are used. Scanning means for irradiating the entire irradiation area of the sample surface with the electron beam by scanning the sample surface with the electron beam, and mapping projection for forming an electron from the sample surface irradiated with the electron beam on the detection section. And an image processing unit that processes a signal output based on an image formed by the image projecting unit. 2. A sample moving means for moving the sample is provided,
The inspection apparatus according to claim 1, wherein the entire inspection area on the sample surface is irradiated with an electron beam by the scanning by the scanning unit and the movement of the sample by the sample moving unit. 3. The inspection apparatus according to claim 1, wherein the image processing unit detects an abnormality on a sample surface by comparing images at a plurality of irradiation locations. 4. The electron beam source according to claim 1, wherein the plurality of electron beam sources are installed at positions that are rotationally symmetrical and evenly divided with respect to a central axis of the image projection unit. Inspection device described in one. 5. The inspection apparatus according to claim 1, wherein the sample is a semiconductor wafer in the process of being processed. 6. An inspection method for inspecting the condition of a sample surface by irradiating a sample with an electron beam and detecting electrons generated from the sample surface, wherein a plurality of electron beams are output from each of a plurality of electron beam sources. ,
The process of irradiating approximately the same place on the sample surface with corresponding electron beams from different electron beam sources, and the scanning of these electron beams on the sample surface and the movement of the sample causes the entire inspection area of the sample surface to be exposed to electron beams. And a step of forming an image of electrons from the sample surface irradiated with the electron beam on the detection part, and a step of processing a signal based on this image formation. Inspection method. 7. The inspection method according to claim 6, wherein the sample is a semiconductor wafer in the process of being processed.