JP2002216684A - Electron beam apparatus, method for detecting displacement of axis of electron beam and method for manufacturing device using electron beam apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect an incident position and an incident angle of a beam. SOLUTION: An electron beam radiated from a radiating means 1 irradiates a sample through a deflecting means 4 and the first and second masks. When a displacement is detected, an opening of the first mask is scanned by the deflecting means 4 and the beam limited by the first mask irradiates the second mask 3. When the incident angle and the incident position are displaced, a beam region which is a part of the beam scanned by the deflecting means 4 and irradiates the second mask is eccentric, and an eccentric state is detected by an electron detecting means 5 and an axis displacement detecting means 6. When an apparatus uses multi-beam, the first mask is disposed in an opening for determining the number of openings of an optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam apparatus for irradiating a sample surface with an electron beam, and a method for manufacturing a semiconductor device including a step of evaluating a semiconductor wafer for defect inspection or the like using the electron beam apparatus. About the method.

[0002]

2. Description of the Related Art There is known an electron beam apparatus for irradiating an electron beam emitted from an electron gun onto a sample surface via a deflector or an electron lens. Examples of devices using this electron beam device include a scanning electron microscope that focuses and scans an electron beam in a spot shape and observes a sample surface, and an electron beam drawing device that directly draws a device pattern on a semiconductor wafer. There is. In such an electron beam device, the electron beam must pass accurately through the center of the deflector or the electron lens. However, the deflection magnetic field of the deflector usually becomes non-uniform when the electron beam deviates from the center of the deflector. There has occurred. When the electron beam deviates from the center position of the electron lens and undergoes a lens action, the beam irradiation position similarly shifts due to the spherical aberration of the lens.

[0003] Therefore, efforts have been made to mount the electron gun, the deflector, and the electron lens with strict accuracy so that the electron beam accurately passes through the center position of the deflector and the electron lens. However, despite such efforts, lack of accuracy has occurred.
The relative displacement between the electron gun and the deflector or the electron lens remains, and the axis of the electron beam deviates largely from the center position of the deflector or the electron lens. Therefore, it is necessary to adjust the alignment of the electron beam. FIG. 1 shows a charged beam device capable of aligning the beam axis with the center position of the aperture.
This will be described below with reference to FIGS.

In FIG. 13, an axis aligning mechanism 72, a sub deflection coil 73, a main deflection coil 74, and an objective lens 75 are arranged on the axis of an electron beam emitted from an electron gun 71. Usually, the electron beam is designed to pass through the center positions of the sub deflection coil 73, the main deflection coil 74, and the objective lens 75. However, as mentioned above, the axis of the electron beam is
Since there is a case where the beam is deviated from the center position such as 3 or the like, the beam is aligned by the axis alignment mechanism 72. As shown in FIG. 14A, the axis aligning mechanism 72 is configured by arranging a deflection coil 78 for axis alignment, a reflected electron detector 79, and an aperture mask 80 on the beam axis of the electron gun 71. The aperture mask 80 is arranged so that its center is coaxial with the centers of the sub-deflection coil 73, the main deflection coil 74, and the objective lens 75 at the subsequent stage.

[0005] The deflection coil 78 for axis alignment is shown in FIG.
As shown in (2), first, the electron beam is swung in the X direction. When the aperture mask 80 is irradiated with an electron beam, reflected electrons are generated from the irradiated area and detected by a reflected electron detector 79. On the other hand, when an electron beam is applied to the opening of the aperture mask 80, the electron beam passes through the opening, and thus no reflected electrons are detected.
Therefore, by oscillating the electron beam in the X direction, the rising and falling edge signals are detected by the reflected electron detector 79 at the time when the points A and B at the edges of the aperture of the aperture mask 80 are irradiated with the electron beam. Is detected.
Based on the detected edge signal, an arithmetic and control unit (not shown) such as a CPU calculates the coordinates of points A and B, and further calculates the coordinates of the middle point C of points A and B.

Next, the deflection coil 78 for axis alignment is moved to the point C
The electron beam in the Y direction so as to pass through. Based on the edge signal detected in the same manner, the CPU obtains the coordinates of the points D and E at the edge of the opening, and calculates the coordinates of the middle point F from the coordinates. This point F is the center position of the aperture mask 80. As described above, the center position of the aperture mask 80 is obtained, and by irradiating the position with the electron beam, the axis of the electron beam is aligned with the center position of the aperture mask 80 and the sub-stage at the subsequent stage as shown in FIG. It can be adjusted to the center position of the deflection coil 73, the main deflection coil 74, and the objective lens 75.

[0007]

However, in the above-mentioned prior art, the beam incident position can be adjusted to the center position of the aperture, but the deviation of the incident angle cannot be detected and corrected. . That is, as shown in FIG. 16, when there is a deviation in the installation angle of the electron gun 71, a deviation occurs in the incident angle of the beam when entering the aperture mask 80. Also in this case, it is possible to detect the center position of the aperture mask 80 and to make the electron beam incident on the center position by oscillating the beam by the deflection coil 78 for axial alignment.

However, since the incident angles are shifted,
With respect to the sub-deflection coil 73, the main deflection coil 74, and the objective lens 75 in the latter stage, the electron beam enters each off the center position, and eventually, when performing deflection control and lens control, aberration occurs. I will. Therefore, in the axial alignment of the electron beam, it is necessary to consider not only the incident position at the center position of the aperture mask 80 but also the incident angle at that time.

A first object of the present invention is to solve the above-mentioned problems of the prior art, and to detect an axis deviation including not only the beam incident position but also the beam incident angle. , And a method for detecting an axis shift in an electron beam device. A second object of the present invention is to provide a semiconductor manufacturing method including a step of evaluating a semiconductor wafer using an electron beam apparatus capable of detecting a beam incident position and an axis deviation of an incident angle. .

[0010]

In order to achieve the above object, in an electron beam apparatus according to the present invention, there is provided an irradiation means for irradiating a plurality of electron beams onto a sample surface; A first mask having a first opening through which an electron beam passes, an optical component such as a lens having a second opening through which the electron beam passes through the first opening, an electron source, and an electron source. A deflecting unit disposed between the first opening and the first opening, and deflecting the electron beam emitted from the electron source;
An electron detecting means for detecting an electron beam irradiated to the second opening among the electron beams passing through the first opening; and a beam axis of the irradiating means based on a distribution of electrons detected by the electron detecting means. An axis deviation detecting means for detecting an axis deviation from a reference axis passing through the centers of the first and second apertures, and a secondary optical system for guiding secondary electrons emitted from the sample to a group of detectors, It is characterized in that a plurality of electron beams are applied to positions separated from each other by a distance resolution of the secondary optical system.

In one embodiment of the above-described electron beam apparatus according to the present invention, the second opening also serves as an electron detecting means, and is configured to detect electrons of the directly irradiated electron beam. The first mask may also serve as an electron detection unit, and may be configured to detect at least one of secondary electrons and reflected electrons generated by irradiation of an electron beam. Further, in one embodiment of the electron beam apparatus according to the present invention, an opening for determining a numerical aperture NA is provided in a primary optical system of the electron beam apparatus, and the opening is formed by a first mask. Is equivalent to

According to the present invention, there is also provided a method of detecting an axial deviation of an electron beam in the above-mentioned electron beam apparatus, wherein the electron beam scans a first opening, and among the electron beams passing through the first opening, An electron of an electron beam irradiated on a second mask having a second opening coaxial with the first opening is detected. Based on a distribution of the detected electrons, a beam axis of the irradiation unit and first and second electrons are detected. A method for detecting an axis deviation of the electron beam from a reference axis passing through the center of the aperture of the electron beam. The present invention further provides a semiconductor device manufacturing method including a step of evaluating a wafer during or after a process using the above-described electron beam apparatus.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram for explaining the principle of detecting an axis shift in a first embodiment of the electron beam apparatus according to the present invention. The electron beam apparatus includes an irradiation unit 1 for irradiating an electron beam onto a sample surface, and a first mask disposed between the irradiation unit 1 and the sample and provided with a first opening 2a through which the electron beam passes. 2 and the first opening 2a
A second mask 3 provided with a second opening 3a through which an electron beam passing therethrough is provided; an irradiation means 1 and a first mask 2
And a deflecting means 4 for deflecting the electron beam irradiated from the irradiating means 1. When the deflecting means 4 scans the first opening 2 a with the electron beam, the deflecting means 4 passes through the first mask 2. Detecting means 5 for detecting the electrons of the electron beam irradiated to the second mask 3 out of the electron beams limited by the irradiation, and irradiating means 1 based on the output distribution of the electrons detected by the electron detecting means 5. Misalignment detecting means 6 for detecting misalignment between the beam axis of the laser beam and a reference axis passing through the centers of the two apertures.
And

In the electron beam apparatus of the first embodiment, for example, as shown in FIG. 1A, the electron beam scans the first opening 2a by the deflecting means 4. At this time, since the electron beam is restricted by the first mask 2, only the electron beam that has passed through the first opening 2 a reaches the second mask 3 and scans the surface of the second mask 3. Will be.
Then, the electron detecting means 5 detects the electrons of the electron beam applied to the second mask 3. At this time, the detection of the electrons performed by the electron detection means 5 not only directly detects the electrons of the electron beam irradiated on the second mask 3, but also detects the electrons from the second mask 3 when the electron beam is irradiated. Indirect detection for detecting generated electrons (secondary electrons, reflected electrons, etc.) is also included.

Next, the axis deviation detecting means 6 determines the axis of the electron beam from the reference axis based on the output distribution of the detected electrons (specifically, corresponding to the scanned image of the second mask 3). Detect the deviation. In the axis deviation detecting means 6,
For example, as shown in FIG. 1B, when the electron beam is obliquely incident, the area of the electron beam irradiated on the right side of the second mask 3 is enlarged, and the electron beam is not irradiated on the left side. Further, as shown in FIG. 1C, when the incident position of the electron beam shifts to the right, the area of the electron beam irradiated on the right side of the second mask 3 remains constant and does not change much. Is no longer irradiated with an electron beam. As described above, depending on how the electron beam restricted via the first mask 2 is irradiated on the second mask 3, it is possible to detect the deviation of the incident angle and the incident position of the beam axis. .

FIG. 2 is a block diagram for explaining the principle of detecting an axis shift in the electron beam apparatus according to the second embodiment of the present invention. This device is the same as the electron beam device of the first embodiment shown in FIG. 1, except that the first mask 2 also serves as the electron detecting means 5,
Is configured to detect at least one of a secondary electron and a reflected electron generated from the mask 3. In the electron beam apparatus according to the second embodiment, when the electron beam is irradiated on the second mask 3, secondary electrons and reflected electrons generated from the irradiated area are detected by the first mask 2. be able to.

FIG. 3 is a block diagram for explaining the principle of detecting an axis shift in the electron beam apparatus according to the third embodiment of the present invention. This device is the same as the electron beam device of the first embodiment shown in FIG. 1, except that the second mask 3 also serves as the electron detecting means 5, and the second mask 3 is used for irradiating the electron beam to the mask. It is configured to directly detect the electrons of the beam.

Next, the electron beam apparatus of any one of the first to third embodiments shown in FIGS. 1 to 3 is used as an evaluation apparatus for evaluating a defect on a surface of a semiconductor wafer, a line width, and the like. The case where this is applied will be described. FIG. 4A is a schematic diagram showing an optical system and a control system of the electron beam device according to the present invention. In FIG. 2A, the electron beam emitted from the electron gun 1 is focused by a condenser lens 2 to form a crossover at a point 4. In order to determine the aperture angles for the plurality of beams, an aperture plate, that is, an aperture plate 21 is provided at the position of the point 4. Below the condenser lens 2, a first multi-aperture plate 3 having a plurality of small openings is arranged, and a plurality of primary electron beams are formed by the plurality of small openings provided in the opening plate 3. Each of the formed primary electron beams is reduced by the reduction lens 5 and projected onto a point 15. Then, after focusing at the point 15, the sample wafer 8 placed on the stage 20 is focused via the Wien filter (EXB separator) 6 and the objective lens 7.
A plurality of primary electron beams from a plurality of small apertures of the first multi-aperture plate 3 are deflected by a deflector 19 disposed between the reduction lens 5 and the objective lens 7 so as to simultaneously scan the surface of the wafer 8. Is done.

In order to prevent the field curvature aberration between the reduction lens 5 and the objective lens 7, the first multi-aperture plate 3 has a small aperture on the circumference as shown in FIG. Are arranged, and X, which is the scanning direction of raster scanning,
The positional relationship of the openings is set such that the points projected in the direction are substantially equally spaced. In FIG. 4B, a small opening of the first opening plate 3 is indicated by reference numeral 3. The plurality of focused primary electron beams irradiate a plurality of points on the wafer 8, and the secondary electron beams emitted from the plurality of irradiated points are attracted and narrowed by the electric field of the objective lens 7. , Are deflected by the Wien filter 6, and then input to the secondary optical system. The image by the secondary electron beam focuses on point 16 which is closer to objective lens 7 than point 15. This is because a plurality of primary electron beams each have energy of about 500 eV on the surface of the wafer 8, whereas the secondary electron beam has energy of only several eV.

The secondary optical system has magnifying lenses 9 and 10, and the secondary electron beam passing through these magnifying lenses forms an image on the second multi-aperture plate 11. The secondary optical system is also provided with an aperture or aperture plate 22 for determining the aperture angle of the system.
Are arranged at positions where the principal rays intersect. Then, the light passes through a plurality of openings of the second multi-aperture plate 11 and is detected by a plurality of detectors 12 provided corresponding to these openings. Note that the plurality of openings of the second multi-aperture plate 11 arranged in front of the detector 12 and the plurality of openings of the first multi-aperture plate 3 are, as shown in FIG. It corresponds to one to one. It goes without saying that the detector 12 and the plurality of apertures have a one-to-one correspondence. The aperture plate 22 having an opening for determining the opening angle of the secondary optical system is provided at a position where the principal rays intersect.

Each of the detectors 12 converts the received secondary electron beam into an electric signal representing its intensity. After the electric signal from each detector 12 is amplified by the amplifier 13,
The image is converted into sub-image data in the image processing unit 14. In a normal operation, the image processing unit 14 is also supplied with a scanning signal supplied from the deflector control unit 48 to the deflector 19 to deflect the primary electron beam. The deflector control unit 48 controls not only the deflector 19 but also the deflectors 17, 23, 24, 25. In addition,
Reference numeral 44 denotes a CPU, which controls the entire electron beam apparatus.

When the primary electron beam that has passed through the opening of the first multi-aperture plate 3 is focused on the surface of the wafer 8, distortion, field curvature, and astigmatism caused by the primary optical system are caused.
Care should be taken to minimize the effects of the two aberrations. Further, if the minimum value of the interval between the irradiation spots of the plurality of primary electron beams is separated by a distance larger than the aberration of the secondary optical system, crosstalk between the plurality of electron beams can be eliminated.

The aperture plate 21 in FIG. 4 is made of metal and is formed in a disk shape, and it is necessary to align the axis of the electron beam. Hereinafter, the operation of aligning the electron beam with the aperture plate 21 will be described with reference to FIGS. FIG. 5 is an enlarged view of the periphery of the aperture plate 21. 33a is an upper electrode of the reduction lens 5, and the upper electrode 33a is arranged so as to be orthogonal to the optical axis of the primary optical system 25. Further, a beam passage hole 33b for passing a primary beam is formed in the upper electrode 33a. Above the upper electrode 33a of the reduction lens 5,
A metal cylindrical holding portion 33c is provided so as to surround the beam passage hole 33b. The above-mentioned metal disk-shaped aperture plate 21 is attached to the inner wall thereof via a ceramic insulating portion 33 d so as to be orthogonal to the optical axis of the primary optical system 25. In the aperture plate 21,
An opening 21a having a smaller diameter than the beam passage hole 33b is formed. The opening 21a and the primary beam passage hole 33b are arranged so that their respective centers are coaxial with each other, and this axis becomes the reference axis (the central axis of the reduction lens 5). Since a crossover is formed at the position of the opening 21a of the aperture plate 21, all of the plurality of primary beams are aggregated into one spot beam.

Using the above configuration, the deviation of the incident angle and the incident position of the beam are corrected as follows. Deflector 1
Reference numerals 7 and 23 control the deflection of the spot beam in accordance with horizontal and vertical (X and Y direction) scanning signals from the deflector control unit 48, and repeatedly scan the aperture 21a of the aperture plate 21 with the spot beam.

A positive voltage is applied to the aperture plate 21. For this reason, it is possible to take in electrons of a spot beam that is directly applied to the surface of the aperture plate 21. Further, when the spot beam passes through the opening 21a and irradiates the edge portion of the beam passage hole 33b, electrons (at least one of secondary electrons and reflected electrons) generated from the irradiated portion can be taken in. . Ammeter 52
Detects the captured electrons as a current signal. The image processing unit 14 A / D converts the current signal in synchronization with the horizontal and vertical scanning signals to the deflectors 17 and 23, and generates a scanned image.

FIG. 6 shows a scanned image of the spot beam. The scanned image is an image in which the beam passage hole 33b and the opening 21a are viewed from above. The area A indicates the aperture plate 21, the area B indicates an edge portion of the beam through hole 33b, and the area C indicates the beam through hole 33b. Region A is a high-brightness image because a spot beam directly applied to the aperture plate 21 is detected, and region B is a medium-brightness image because electrons generated from the edge of the beam passage hole 33b are detected. In the area C, the spot beam has the aperture 2
Since no electrons are detected after passing through the beam passing hole 1a and the beam passage hole 33b, a low-luminance image is formed. Using this scanned image,
An incident angle shift and an incident position shift are detected.

The state of the incident angle shift will be described with reference to FIG. Note that, for the sake of simplicity, the description will be made assuming that the beams are irradiated in parallel. (1) shows a state in which the beam axis coincides with the reference axis and there is no deviation of the incident angle. At this time, the region B has an annular shape, and the interval D, which is the width thereof, has a constant value of D1. (2) shows a state in which an angle shift has occurred between the beam axis and the reference axis. Here, the incident angle of the spot beam is shifted, and the area of the spot beam irradiated on the left side of the primary beam passage hole 33b is enlarged. (3) shows a state in which the beam axis and the reference axis further have a large angle shift. The area of the spot beam irradiated on the left side of the primary beam through hole 33b further expands,
On the right side, the spot beam is cut off by the aperture plate 21 and is not irradiated at all. The states relating to these incident angle shifts can be obtained as scanned images in the image processing unit 14.

The state of the incident position shift will be described with reference to FIG. In (1), the beam axis coincides with the reference axis,
This shows a state where there is no incident position shift. At this time, the centers of the regions A, B, and C coincide with each other at the center 0. (2) shows a state in which a position shift has occurred between the beam axis and the reference axis. Here, the incident position of the spot beam has moved to the left, and the images of the areas B and C have moved to the right. (3) shows a state where the beam axis and the reference axis further have a large displacement. The images of the areas B and C have moved further to the right. The state of these incident position shifts can also be obtained as a scanned image in the image processing unit 14.

By the way, regarding the axial deviation of the electron beam, the above-described incident angle deviation and incident position deviation actually occur simultaneously, and the state can be shown in FIG. 9 (1). When performing axis alignment in this state, first, the image processing unit 14 performs a filtering process using an edge-preserving smoothing filter on the scanned image illustrated in FIG. 9A to reduce noise. Next, edge enhancement processing is performed by a high-frequency enhancement filter. Further, the edge portion is binarized and thinned by the threshold value processing, and the region A and the region B are binarized.
, A boundary line between the regions B and C, and a boundary line between the regions A and C are extracted.

Next, the CPU 44 calculates coordinate data of the extracted boundary line, and obtains an interval D in the X direction. Then, the difference between the interval D and D1 shown in FIG. 10A is calculated to determine the incident angle shift amount in the X direction, and the correction deflection amount for correcting the shift amount is calculated. The calculated correction deflection amount is supplied to the deflector control unit 48, which controls the deflectors 17 and 23 to tilt the spot beam and correct the X-direction incident angle deviation. I do. Thereby, as shown in FIG. 9 (2),
A scanned image in which the incident angle shift in the X direction has been corrected is obtained.

The image processing unit 14 has a CPU
Under the control of 44, image processing for boundary line extraction is executed for the scanned image shown in FIG. Based on the boundary line, the CPU 44 calculates the distance D in the Y direction, obtains the amount of deviation of the incident angle in the Y direction from the difference from D1, and calculates the correction deflection amount. The CPU 44 supplies the corrected deflection amount to the deflector control unit 48, thereby controlling the deflectors 17 and 23 according to the corrected deflection amount to tilt the spot beam and correct the Y-direction incident angle shift. The CPU 44
The operation of correcting the deviation of the incident angle is repeated until the interval D in the direction and the Y direction coincides with D1. FIG. 9C shows a scanned image in which the incident angle shift has been corrected.

When the correction of the incident angle deviation is completed, the incident position deviation is corrected next. The image processing unit 14 corresponds to FIG.
Scanned image shown at 0 (1) (same as the image at (3) in FIG. 9)
, Image processing for boundary line extraction is executed. And
The CPU 44 determines the coordinates of the center 0 in the area A and the area B
And the coordinates of the center 0 ′ in the area C are calculated.
Then, the X-direction incident position deviation amount and the Y-direction incident position deviation amount are obtained from the coordinates of the center 0 ′ and the coordinates of the center 0 ′, and the correction deflection amount for correcting the incident position deviation is calculated. Based on the obtained corrected deflection amount, the deflector control unit 48 sets the deflector 17
23 is controlled to shift the spot beam in the X direction and the Y direction to correct the incident position shift.

FIG. 10B shows a scanned image in which the incident position shift has been corrected. The centers of the regions A, B, and C coincide at the center O, and the incident position shift is corrected.
This completes the axis alignment operation. As described above, the CPU
The deflectors 17 and 23 shift and tilt the primary beam based on the incident angle deviation correction deflection amount and the incident position deviation correction deflection amount calculated in 44, whereby the primary beam is always shifted to the central axis of the reduction lens 5. And can be made incident.

As described above, in the present embodiment, the axis deviation between the reference axis and the beam axis depends on how the beam passing through the opening 21a of the aperture plate 21 is irradiated on the upper electrode 33a of the reduction lens 5. Has been detected. Therefore, even if the electron gun 1 and the reduction lens 5 are displaced from each other and the incident angle and the incident position of the beam incident on the reduction lens 5 are deviated, the primary beams are tilted and shifted by the deflectors 17 and 23. By doing so, the primary beam can always be made incident on the central axis, and a clear image with little aberration can always be obtained.

Conventionally, a beam axis and a reduction lens 5 are used.
Although the design precision that exactly matches the center axis of the beam was required, the fine adjustment of the beam axis can be performed later, so that the production tolerance is remarkably improved. Alternatively, the primary beam may be detected by both the aperture plate 21 and the upper electrode 33a of the reduction lens 5 to acquire a scan image, and the acquired two scan images may be superimposed and displayed. Further, a plurality of secondary beams are used instead of a spot beam, and the plurality of secondary beams are
Similarly, when the light is condensed on the axis 2, the above-described axis deviation detection and axis alignment operation can be performed.

Next, the semiconductor device manufacturing method of the present invention will be described. The semiconductor device manufacturing method of the present invention
A semiconductor device is manufactured while evaluating a wafer in various manufacturing processes using the above-described evaluation apparatus. A general method for manufacturing a semiconductor device will be described with reference to the flowcharts in FIGS. As shown in FIG. 11, the semiconductor device manufacturing method is roughly divided into a wafer manufacturing step S1 for manufacturing a wafer, a wafer processing step S2 for performing a necessary processing on the wafer, and a mask required for exposure. It comprises a mask manufacturing step S3, a chip assembling step S4 for cutting out chips formed on the wafer one by one to enable operation, and a chip inspection step S5 for inspecting completed chips. Each of these steps
It includes several sub-steps.

Among the above-mentioned steps, a step that has a decisive effect on the manufacture of a semiconductor device is a wafer processing step. This means that in this process, a designed circuit pattern is formed on a wafer, and a memory or M
This is because many chips that operate as PUs are formed.
As described above, it is important to evaluate the processing state of the wafer performed in the sub-process of the wafer processing process which affects the manufacture of the semiconductor device. The sub-process will be described below.

First, a dielectric thin film serving as an insulating layer is formed, and a metal thin film for forming a wiring portion and an electrode portion is formed. The thin film is formed by CVD, sputtering, or the like. Next, the formed dielectric thin film and metal thin film, and the wafer substrate are oxidized, and using the mask or reticle created in the mask manufacturing process S3,
In a lithography process, a resist pattern is formed. Then, the substrate is processed according to a resist pattern by dry etching technology or the like, and ions and impurities are implanted. Thereafter, the resist layer is peeled off, and the wafer is inspected. Such a wafer processing step
This process is repeated for a required number of layers, and a wafer before being separated for each chip in the chip assembling step S4 is formed.

FIG. 12 is a flowchart showing a lithography process which is a sub process of the wafer processing process of FIG. As shown in FIG. 4, the lithography process includes a resist coating process S21, an exposure process S22, a developing process S23, and an annealing process S24. In the resist application step S21, a resist is applied on the wafer on which the circuit pattern has been formed using CVD or sputtering, and in the exposure step S22, the applied resist is exposed. Then, in a developing step S23, the exposed resist is developed to obtain a resist pattern,
In the annealing step S24, the developed resist pattern is annealed and stabilized. These steps S21
Steps S24 to S24 are repeatedly performed by the required number of layers.

In the method of manufacturing a semiconductor device according to the present invention, the evaluation apparatus described above is used in a chip inspection step S5 for inspecting a completed chip, so that even a semiconductor device having a fine pattern can be distorted.
Since an image with reduced blur and the like can be obtained, a defect of the wafer can be reliably detected. Note that the processing device in which the evaluation device is disposed in the vicinity may be any processing device as long as it performs a process requiring evaluation.

[0041]

As described above, the first embodiment according to the present invention is described.
In the electron beam apparatus according to the first embodiment, the incident angle shift and the incident position shift of the beam axis are detected depending on how the electron beam restricted via the first mask is irradiated on the second mask. be able to. In the electron beam apparatus according to the second embodiment of the present invention, when the electron beam is irradiated on the second mask, the secondary electrons generated from the irradiated area,
Backscattered electrons can be detected by the first mask. Therefore, since the first mask also serves as the electron detecting means, the number of components can be reduced, and the configuration of the device can be simplified. In the electron beam apparatus according to the third embodiment of the present invention, the second mask can detect the electrons of the directly irradiated electron beam. Therefore, since the second mask also serves as the electron detecting means, the number of components can be reduced, and the configuration of the device can be simplified.

In the method of aligning the electron beam, the deviation between the reference axis and the beam axis is detected based on how the electron beam restricted via the first mask is irradiated on the second mask. can do. As described above, in the electron beam apparatus to which the present invention is applied, since the axis alignment of the electron beam can be performed for both the incident angle and the incident position, the electron beam always passes through the center position of the deflector and the electron lens. Thus, aberrations of the deflector and the electron lens can be suppressed. In addition, since the axial alignment can be adjusted later even if aging occurs, a stable electron beam device that can withstand long-term use can be realized.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a principle block diagram of the present invention.

FIG. 3 is a principle block diagram of the present invention.

FIG. 4 is an overall configuration diagram of an embodiment of an electron beam device according to the present invention.

FIG. 5 is an enlarged view around an aperture plate.

FIG. 6 is a diagram showing a scanned image of a spot beam. ,

FIG. 7 is a diagram illustrating an incident angle shift.

FIG. 8 is a diagram for explaining an incident position shift.

FIG. 9 is a diagram illustrating an axis alignment operation.

FIG. 10 is a diagram illustrating an axis alignment operation.

FIG. 11 is a flowchart of a method of manufacturing a semiconductor device by applying the evaluation device according to the present invention.

FIG. 12 is a flowchart of a lithography step which is a sub-step of the wafer processing step shown in FIG. 11;

FIG. 13 is a configuration diagram of a conventional electron beam device.

FIG. 14 is a diagram illustrating a conventional axis alignment operation.

FIG. 15 is a diagram illustrating a conventional axis alignment operation.

FIG. 16 is a diagram illustrating a case where there is a deviation in the incident angle.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 37/28 H01L 21/66 J H01L 21/66 G01R 31/28 L 11-1 Haneda Asahimachi, Ota-ku Ebara Meister Co., Ltd. (72) Inventor Shinji Noji 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (72) Inventor Toru Satake Haneda, Ota-ku, Tokyo 11-1 Asahicho EBARA CORPORATION F-term (reference) 2G132 AA00 AF13 AL11 4M106 AA01 AA02 BA02 CA38 DB04 DB05 DB12 DB18 DB30 DJ01 DJ20 5C030 AA07 AB02 AB06 5C033 FF10 JJ07 MM07 UU04 UU10

Claims (5)

[Claims] 1. An electron beam apparatus, comprising: an irradiation unit for irradiating a plurality of electron beams onto a sample surface; and a first opening disposed between an electron source and the sample and having a first opening through which the electron beams pass. A mask, an optical component such as a lens having a second opening through which the electron beam passing through the first opening passes, and an electron beam disposed between the electron source and the first opening and irradiated from the electron source Deflecting means for deflecting the electron beam, and, when the electron beam scans the first opening by the deflecting means, an electron for detecting an electron beam irradiated to the second opening among the electron beams passing through the first opening. Detecting means, based on a distribution of electrons detected by the electron detecting means,
Axis shift detecting means for detecting an axis shift between a beam axis of the irradiating means and a reference axis passing through the centers of the first and second openings; a secondary optical system for guiding secondary electrons emitted from the sample to a group of detectors And an electron beam apparatus, wherein the plurality of electron beams are applied to positions separated from each other by a distance resolution of a secondary optical system. 2. An electron beam apparatus according to claim 1, wherein said second aperture also serves as an electron detecting means, and detects electrons of an electron beam directly irradiated. 3. The electron beam apparatus according to claim 1, wherein a numerical aperture NA is provided in a primary optical system of the electron beam apparatus.
An electron beam apparatus, comprising: an opening for determining the size of the first mask; and the opening corresponds to a first mask. 4. A method for detecting an axial deviation of an electron beam in the electron beam apparatus according to claim 1, wherein the electron beam scans a first opening and passes through the first opening. An electron beam, which is irradiated on an optical component such as a lens having a second opening coaxial with the first opening, is detected from the electron beam, and based on a distribution of the detected electrons, a beam axis of the irradiation unit and a first axis are detected. And detecting an axis deviation from a reference axis passing through the center of the second opening. 5. A method for manufacturing a semiconductor device, comprising a step of evaluating a wafer during or after a process using the electron beam apparatus according to claim 1.