JPH11260306A - Electron beam inspection apparatus and method therefor, apparatus applying charged particle beam and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam inspection apparatus capable of highly efficiently detecting secondary electrons and/or reflected electrons from a substrate at high speed. SOLUTION: This electron beam inspection apparatus is capable of detecting highly efficiently first secondary electrons 202 and/or reflected electrons from a substrate at high speed, without losses by deflection at a narrow angle by accelerating, deflecting, and radiating the first secondary electrons 202 and reflected electrons generated on the surface of a substrate to a plate member 7 to generate second secondary electrons 203 and leading the second secondary electrons to a detector 13 with a small surface area by an accelerating and converging electric field formed by the detector 13, an attracting electrode 14, and a plate member 7 to be detected. The electron beam inspection apparatus can also carry out high speed and highly accurate inspection of a semiconductor wafer including an insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit pattern inspection apparatus and method, and a charged particle beam application apparatus and method, and more particularly, to a pattern on a semiconductor wafer for irradiating low-acceleration electrons and acquiring an image at high speed. It is about inspection.

[0002]

2. Description of the Related Art With the miniaturization of circuit patterns on semiconductor wafers, circuit pattern inspection apparatuses using electron beams have been put to practical use. For example, Japanese Patent Application Laid-Open No. Sho 59-192943 discloses that a primary electron beam is decelerated and irradiated onto a sample, secondary charged particles from the sample are detected at high speed, and pattern defects are inspected. Also, Japanese Patent Application Laid-Open No. 09-17191
The gazette discloses a secondary electron detection technique in which a secondary electron generated from the reflective plate is attracted and captured by first hitting the reflective plate without directly attracting the electron to the detector.

Further, as described in JP-A-5-258703 and JP-A-6-1391985, a high-acceleration electron beam is decelerated immediately before a sample, and irradiated on the sample as a substantially low-acceleration electron beam. There is a known technique.

[0004]

However, the prior art has the following problems. (A) The retarding electric field is an accelerating electric field for secondary electrons and reflected electrons generated from the sample substrate. Therefore, secondary electrons and reflected electrons become highly accelerated electrons, cannot be captured only by the attraction electric field of the detector, and need to be deflected to a large angle by the EXB deflector toward the detector. For that purpose, it is necessary to apply a strong electromagnetic field to the EXB deflector. However, in the EXB deflector, there is a limitation that electrons cannot be deflected beyond the distance between the deflection plates.
Since the interval between the deflecting plates is inversely proportional to the strength of the deflecting electromagnetic field, increasing the deflecting field weakens the deflecting electromagnetic field. There are limitations on the applied voltage and coil current due to the relationship between the withstand voltage of the deflector and the power supply. That is, due to the configuration of the EXB deflector itself and the positional relationship between the detector and the detector, it is difficult to deflect at a large angle and to guide highly accelerated secondary electrons and reflected electrons to the detector. It becomes more remarkable in the case of the retarding voltage. (B) On the other hand, in order to collect secondary electrons to the detector with a small amount of deflection, it is necessary to install the detector close to the central axis of the primary beam. Need to be set apart. However, in this case, there is a problem that the mirror body becomes long and the observation accuracy is reduced due to the influence of vibration and the like. (C) In addition, if the deflection of the EXB deflector is made strong, there is a problem that an aberration occurs in the primary electron beam and it becomes difficult to converge finely with an objective lens. In order to prevent the aberration of the primary electron beam, there is known a technique in which another EXB deflector is provided in addition to the above-described method to cancel the aberration generated by each deflector. However, such a configuration is complicated, and it is difficult to realize an actually high-precision observation image because ideal axis adjustment and the like are required. (D) In order to detect a signal at a high speed with the semiconductor detector, it is necessary to increase the response speed of the semiconductor detection element. It is known that the response speed is proportional to the element area, and when the required response speed is determined, the allowable element area can be determined by performing back calculation. However, there is no specific disclosure about the point that the primary electron beam is scanned at a high speed and the secondary charged particles from the sample are detected by a high-speed detector, that is, a detector having a small detection area. Further, even when the reflector is used in the conventional secondary electron detection technique, no consideration is given to collecting and capturing electrons near the center of the detection region even in the process of attracting electrons to the detector. Therefore, when the detection area is small, a large number of secondary electrons reach outside the detection area. Therefore, it has been difficult for an electron beam inspection apparatus to capture secondary electrons with high efficiency in a small area detection region. In addition, since an accelerating electric field acts on secondary electrons emitted in the normal direction to the sample, secondary charged particles pass through the objective lens, escape to the electron source side, and a large number of particles are lost. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and can efficiently and quickly detect highly accelerated secondary electrons and reflected electrons with a small amount of deflection without reducing accuracy. Therefore, by obtaining a circuit pattern in the manufacturing process of a semiconductor device in which an insulator or an insulator and a conductive material are mixed, the electron beam is used to obtain a high-speed, stable, and high-quality, high-precision image with a large contrast between light and dark. The images can be automatically compared and inspected to detect defects without errors, and the results can be reflected in the manufacturing conditions of the semiconductor device to increase the reliability of the semiconductor device and reduce the defect rate. It is an object of the present invention to provide an electron beam inspection apparatus and a method thereof and a charged particle beam application apparatus and a method thereof.

[0006]

Means for Solving the Problems Representative means for achieving the above object will be described. The configuration of the electron beam inspection apparatus according to the present invention includes an electron source, an electron optical system that converges an electron beam from the electron source, scans and irradiates a sample, a sample stage that holds the sample, and the sample. A deflector for deflecting secondary charged particles and / or reflected electrons from
The secondary charged particles and / or
Or an electrode that generates an electric field that slows down the reflected electrons,
A detector having a plate member for changing the direction of secondary charged particles and / or reflected electrons from the sample, and an opening smaller than the plate member for detecting second charged particles and / or reflected particles from the plate member It is characterized by having.

[0007] The electron beam inspection method and the electron beam inspection apparatus having the above configuration will be functionally described. The amount of deflection of the secondary electrons and reflected electrons from the substrate may be the amount of deflection for irradiating a plate member provided between the primary electron beam and the detector, so that the irradiation is performed with a smaller angle of deflection than in the past. It may be configured to capture second secondary electrons and / or reflected electrons generated therefrom.

As a result, the deflection electromagnetic field of the EXB deflector is
An electromagnetic field weaker than in the related art is sufficient, and the interval between the deflection plates of the EXB deflector can be increased. Therefore, the amount of aberration of the primary electron beam and the loss of secondary electrons and reflected electrons due to collision with the deflection plate are reduced. Furthermore, among the electrons generated in the plate member, especially secondary electrons are 0 to
Since the energy is as low as about 50 eV, a high yield can be obtained by the suction voltage of the detector to which a voltage of several kV is applied.

Further, by forming this plate member from a material having a high secondary electron generation efficiency, it is possible to generate more secondary electrons than secondary electrons from the substrate. The number of secondary electrons trapped in the substrate increases, and the secondary electron detection efficiency can be further improved.

Further, the position and shape of the plate member and the position and shape of the detector peripheral structure are adjusted so that the electric field formed by the detector and the plate member becomes a desired electric field for converging the electrons generated from the plate member. By optimizing, electrons can be efficiently captured in the detection area of the detector smaller in area than the plate member, and detection with a fast response speed can be performed. That is, it is possible to improve the detection speed and the detection efficiency while keeping various conditions such as the installation position of the detector and the applied voltage at the same level as the current conditions.

With the configuration having these functions, it is possible to obtain a clear and stable image of a semiconductor substrate including an insulator by obtaining a high detection speed and a high efficiency of detecting secondary electrons, obtaining a high-contrast and high-precision signal. Thus, it is possible to configure an electron beam inspection apparatus and method capable of performing a high-speed and accurate defect inspection of a semiconductor pattern.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electron beam inspection apparatus according to the present invention will be described below with reference to FIGS.
FIG. 1 is an explanatory view of an electron beam inspection apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory view of a general semiconductor device manufacturing process flow, and FIG. 3 is a part of the electron beam inspection apparatus of FIG. FIG. 4 is a partially enlarged view of the electron beam inspection apparatus of FIG. 1, and FIG. 5 is an explanatory view of an electron beam inspection apparatus according to another embodiment of the present invention.

First, the relationship between the inspection of the semiconductor device and the manufacturing process will be described. As shown in FIG. 2, the semiconductor device manufacturing process repeats a number of pattern forming steps. The pattern forming process generally includes steps of film formation, application of a photosensitive resist, exposure to light, development, etching, removal of the resist, and cleaning. In each of these steps, if the manufacturing conditions are not optimized, the circuit pattern of the semiconductor device cannot be formed normally.

For example, if an abnormality occurs in the film forming process shown in FIG. 2, particles are generated, adhere to the wafer surface, and an isolated defect or the like occurs. In addition, during exposure after resist application, if the conditions such as focus and exposure time are not optimal, there will be places where the amount or intensity of light applied to the resist is too large or insufficient,
Shorts and disconnections, so-called pattern thinning, will be involved. If there is a defect on the mask reticle at the time of exposure, similar pattern shape abnormality is likely to occur. In addition, when the etching amount is not optimized, and due to a thin film or a particle generated during the etching, a short circuit, a projection, an isolated defect, an opening defect, or the like occurs. Abnormal oxidation is likely to occur at the corners of the pattern and other places depending on the condition of running out of water during drying during cleaning.

Therefore, in the wafer manufacturing process, it is necessary to optimize the processing conditions so that these defects do not occur, and it is necessary to detect the occurrence of the abnormality at an early stage, feed it back to each step, and eliminate the cause of the defect. is there. Therefore, in the present embodiment, an example will be described in which the inspection is applied after resist exposure and development in the n-th pattern forming step shown in FIG. Hereinafter, an outline of an inspection method and an inspection apparatus for detecting the above-described defect will be described.

The basic structure of an electron beam inspection apparatus according to the present invention is to detect secondary electrons and reflected electrons generated from a substrate on which a circuit pattern is formed, at high speed and efficiently, and convert the image into an image signal to perform a high-precision circuit pattern inspection. Irradiating the plate member other than the detector with the secondary electrons and the reflected electrons, and converging and attracting the second secondary electrons or the reflected electrons generated therefrom. Then, the light is captured by a detector. As a result, as described in (b) above, there is no need to separate the detector from the sample, and secondary electrons and reflected electrons generated on the sample surface can be efficiently detected at high speed and with a small angle of deflection without loss. Thus, it is possible to obtain a comparative inspection image using an electron beam having a large contrast.

[Embodiment 1] An embodiment of the present invention will be described with reference to FIG. An electron beam inspection apparatus (hereinafter, referred to as an inspection apparatus) is roughly divided into an electron optical system 101,
It comprises a sample chamber 102, a control unit 103, and an image processing unit 104. The electron optical system 101 includes an electron gun 1, an electron beam extraction electrode 2, a condenser lens 3, a blanking deflector 4, a scanning deflector 5, a diaphragm 6, a shield pipe 7, an EXB deflector 8, and an objective lens 9. Have been.

The sample chamber 102 includes an XY stage 1
1, a rotary stage 12, an optical height measuring device 26, and a position monitoring length measuring device 27, and a secondary electron detector 13 is located above the objective lens 9; The output signal is amplified by the preamplifier 21 and becomes digital data by the AD converter 22.

The image processing unit 104 includes a delay circuit 31
And image storage units 30a and 30b, calculation unit 33, defect determination unit 3
4, digital data from the AD converter 22 is taken in, and an electron beam image and an optical image are displayed on a monitor 32.

The control unit 103 is preliminarily input with conditions such as acceleration voltage, electron beam deflection width, deflection speed, sample stage moving speed, and signal acquisition timing of the detector when an electron beam is generated. In accordance with this, an operation command to each section of the inspection apparatus and its operation condition are controlled. The control unit 10
3 is an optical height measuring device 26, a position measuring length measuring device 27
Of the objective lens power supply 25 so that the electron beam is always irradiated to the correct position.
Alternatively, the correction signal is transmitted from the correction control circuit 28 to the scanning signal generator 24.

The electron gun 1 uses a diffusion-supply type thermal field emission electron source, which can provide a comparative inspection image with a small variation in brightness and can increase the electron beam current, so that high-speed inspection is possible. Becomes possible. The electron beam 201 is extracted from the electron gun 1 by applying a voltage to the extraction electrode 2. The electron beam 201 is accelerated by applying a high negative potential to the electron gun 1.

Thus, the electron beam 201 travels in the direction of the sample stage 11 at energy corresponding to the potential of the electron beam, for example, 12 KeV in this embodiment, is converged by the condenser lens 3, and further converged by the objective lens 9. The target substrate 10 (eg, wafer or chip), which is narrowed down and mounted on the XY stage 11, is irradiated. A negative voltage (hereinafter, referred to as a retarding voltage) can be applied to the test substrate 10 by the high-voltage power supply 23.

A ground electrode 29 is provided between the substrate 10 to be inspected and the EXB deflector 8, and a retarding electric field is formed between the ground electrode 29 and the substrate 10. By adjusting the high voltage power supply 23 connected to the substrate 10, the electron beam irradiation energy to the substrate under test 10 can be easily adjusted to an optimum value.

In this embodiment, a potential of -11.5 kV to -3 kV is applied to the substrate 10 as a retarding voltage. For image formation, a method in which the XY stage 11 is stopped and the electron beam 201 is two-dimensionally scanned,
Scans only one dimension and XY in a direction substantially orthogonal to the scanning direction.
One of the methods for continuously moving the stage 11 can be selected. When inspecting only a specific place, the stage 11 is stopped and inspected. When inspecting a wide range of the substrate 10 to be inspected, the stage 11 is continuously moved to inspect it. it can.

In order to acquire an image of the substrate 10 to be inspected, the substrate 10 to be inspected is irradiated with a narrowed electron beam 201 to generate secondary electrons 202 and reflected electrons 204.
By detecting these in synchronization with the scanning of the electron beam 201 and the movement of the stage 11, an image of the surface of the substrate to be inspected can be obtained.

In the automatic inspection as described in this embodiment, it is generally essential that the inspection speed is high, and therefore,
As in a normal SEM, a beam current of the order of pA is scanned at a low speed, and scanning is not performed a plurality of times. Therefore, compared to a normal SEM, it is about 100 times or more, for example, 1
An image was formed by a single scan of a high current electron beam of 00 nA.

In this way, one image is 1000
× 1000 pixels and acquired in 10 msec. The image signal is held with a delay of one image in the delay circuit 31 and is compared and evaluated with the delayed image in synchronization with the capture of the next image to search for defects on the circuit board 10. I made it.

A general description will be given of a process of generating secondary electrons for obtaining an image of the substrate 10 to be inspected. When the primary electron beam 201 enters the solid, it enters the interior, and excites electrons in the shell at each depth to lose energy. At the same time, a phenomenon occurs in which the reflected electrons scattered behind the primary electron beam by the primary electron beam also travel to the surface while exciting the electrons in the solid.

Through these multiple processes, the electrons in the shell become
From the solid surface, beyond the surface barrier to become secondary electrons, from 0 to 5
It goes into vacuum with energy of 0 eV. The smaller the angle formed between the primary electron beam and the solid surface, the smaller the ratio of the entrance distance of the primary electron beam to the distance from the entry position to the solid surface, and the secondary electrons are more likely to be emitted from the surface. Therefore, the generation of secondary electrons depends on the angle between the primary electron beam and the solid surface, and the amount of secondary electrons is information indicating irregularities on the sample surface.

The reflected electrons are electrons that are reflected with little energy loss by the primary electron beam colliding with atoms on the outermost surface, and are caused by differences in the average atomic number of the elements constituting the sample and the irregularities on the surface of the sample. The amount generated is different. These secondary electrons 202 and reflected electrons 204 are deflected by the EXB deflector 8 and collide with the reflector 300.

FIG. 3 shows an enlarged state of the reflector 300, the detector 13, and a part of the electron optical system.
The primary electron beam 201 irradiates the sample substrate 10 to generate first secondary electrons 202 first. First secondary electron 20
2 is accelerated to 11.5 kV to 3.5 keV by the retarding voltage applied to the substrate 10. At the same time, the light is converged and deflected by the objective lens 9 and the EXB deflector 8 and collides with the reflector 300. The reflection plate 300 is grounded. The EXB deflector 8 is connected to the primary electron beam 20.
1 is a deflector that deflects the amount of deflection due to the electric field and the magnetic field to each other, and deflects the secondary electrons 202 by superimposing them.

Here, referring to FIG.
0 will be explained. As shown in the drawing, the reflector 300 is a plate member integrated with a shield pipe 7 for shielding the primary electron beam 201 from an ambient electric field, and has a secondary electron having a cross section parallel to the plane of the plate member. The surface facing the detector 13 was configured to have a curved surface of an elliptical sphere.

In order to irradiate the secondary electrons 202 and the reflected electrons 204 from the substrate 10 (not shown in FIG. 4) without loss, the beam passage hole around the central axis of the primary beam has a size of 0.5.
mmφ. Further, the secondary electrons 202 or the reflected electrons 204 emitted upward from the center point of the EXB deflector 8 in a deflection range of an expected angle of 0.5 to 15 degrees with respect to the central axis can be covered. The position and surface shape of the reflection plate 300 were configured.

The material of the reflection plate 300 is CuBeO
Thus, a configuration is provided in which secondary electrons of about five times the number of irradiated electrons are emitted. From the reflection plate 300, second secondary electrons 203 and reflected electrons having an energy of 0 to 50 eV are generated. The second secondary electrons 203 are attracted to the light receiving surface of the detector 13 by an attraction electric field generated by the detector 13 and an attraction electrode 14 disposed on the front surface of the detector 13.

In this embodiment, the detector 13 is S
i, the detector 13 and the entire detection circuit system are floated at +9 kV, and the suction electrode 14 is used.
Is 0 V, and the effective detection area of the detector 13 is 4 mm ² . The suction electrode 14 has an opening having a diameter of 7 mm on the front of the detector 13 so that the suction electric field of the second secondary electrons is concentrated and formed on the front of the detector 13. Equipotential lines E1, E2, E3,.
Is shown in FIG.

In this embodiment, for example, the initial acceleration of the beam 201 is 12 kV, and the retarding voltage is -11.5 k.
When operated as V, the generated secondary electrons 202 and reflected electrons 204 have a difference of about 500 eV in energy, and the EXB deflector 8 has an angle ratio of approximately 1.03: 1 according to the respective energies. Be deflected. Therefore, in this case, it is possible to deflect the secondary electrons 202 and the reflected electrons 204 to impinge on the reflector 300 at the same time.

On the other hand, when the retarding voltage is -3 kV, the energy of the secondary electrons 202 and the energy of the reflected electrons 204 have a difference of about 9 kV, and a deflection angle ratio of about 3: 1 occurs. However, also in this case, for example, the secondary electrons 20
By deflecting the reflected electrons 204 by about 5 degrees and the reflected electrons 204 by about 1.7 degrees, both can be applied to the reflector. Of course, in either case, it is possible to deflect only the reflected electrons 204 or the secondary electrons 202 by using the vicinity of both ends of the reflection plate 300. That is, by simply adjusting the deflection amount of the EXB deflector 8, the composition information and the unevenness information of the surface of the substrate 10,
Alternatively, these superimposed images can be obtained.

In the present embodiment, the first secondary electrons 202 are deflected about 5 degrees by the EXB deflector 8 toward the installation side of the detector 13. Therefore, the voltage and magnetic field applied to the EXB deflector 8 and the electrode The interval is the retarding voltage 1
At 1.5 kV, 35V, 1.0E-6T,
It was 10 mm. This electromagnetic field can be changed in conjunction with the retarding voltage.

As described above, when the first secondary electrons 202 pass through the EXB deflector 8 due to the small angle deflection, the acceleration by the retarding voltage, and the convergence by the lens 9,
The probability of being lost by colliding with the inner wall of the deflector plate of the XB deflector is
The maximum could be 5% or less.

Next, the electron detection step will be described. Secondary electrons 202 and reflected electrons 204 from the sample substrate 10 collide with the reflecting plate 300, and second secondary electrons 203 and reflected electrons are generated from the respective positions. In this example, the reflection plate 30
Reflector 30 so as to mainly capture secondary electrons 203 from zero.
0 and the position and shape of the detector 13 were optimized.

The second secondary electron 203 is a secondary electron 202
And 204 are generated with an angular distribution from -90 to 90 degrees around the normal direction on the irradiation position of the reflector 300, and accelerated by the electric field near the reflector 300. The shape of the reflecting surface of the secondary electrons 202 and 204 of the reflecting plate 300 is an elliptical sphere, and the normal of the reflecting surface is gathered from any position near the center of the ellipse. The center of the detection area of the detector 13 was arranged in the vicinity. As a result, 90% or more of the secondary electrons 203 could be captured even with a detection element as small as 4 mm ² in area.

Note that the first secondary electrons 202
It is easy to operate so that the angle corresponding to 00 becomes a shallow angle with respect to the reflection plate, thereby further increasing the number of generated secondary electrons. The second secondary electrons 203 are incident on the semiconductor detector and lose a certain amount of energy in the surface layer. Then, the second secondary electrons 203 generate an electron-hole pair and are converted into an electric signal as an electric current.

In a Si semiconductor, it takes about 3.5 eV of energy to form one electron-hole pair. In consideration of the energy loss in the surface layer, the secondary electrons 203 that have been accelerated to 9 KeV and entered are amplified about 1000 times to become an output signal. This current signal is further amplified by the preamplifier 21 and taken in as an image luminance signal. With the above configuration, the conventional secondary electrons 202 are directly transmitted to the detector 13.
As compared with the configuration leading to the above, the loss of the secondary electrons 202 is greatly reduced, the aberration of the primary electron beam 201 can be reduced, and there is an effect of multiplying the secondary electrons.

The detection area of the detector 13 is also 1/4 of the conventional one.
The response speed can be reduced about four times, and the response speed has been increased about four times. As a result, it was possible to follow high-speed signal extraction, and high-speed inspection was realized. Further, since the secondary electrons generated from one point of the sample substrate 10 can be captured with high efficiency, the contrast of the detection signal becomes about 10 times on average,
A high-quality image in which a defect in a circuit pattern can be easily found can be obtained with high accuracy. That is, even when inspecting the substrate to be inspected 10 containing an insulator, an electron beam inspection apparatus is obtained in which a pattern contrast can be obtained at high speed, sharply and stably, and a comparative inspection with few erroneous detections can be performed.

Further, in this configuration, the effect of bending the secondary electrons by the attracted electric field on the front surface of the detector is constant irrespective of the retarding voltage, as compared with the configuration in which the secondary electrons are directly attracted to the detector. . Therefore, stable secondary electron capture can be realized by making the secondary electrons hit the reflector irrespective of the change in the retarding voltage. Since the deflection angle of the secondary electrons is small, the amount of change in the secondary electron deflection electromagnetic field required to obtain the same deflection angle according to the change in the retarding voltage may be small.

Accordingly, the secondary electron deflection which can cope with a wider retarding voltage than the conventional one can be realized by the EXB deflector. Therefore, the retarding voltage can be made higher than that of the related art, and the acceleration energy of the primary electron beam 201 in the electron source can be made higher. As a result, even when irradiation is performed on the substrate 10 with substantially the same energy, it is possible to acquire an image with higher precision and higher resolution than before.

[Embodiment 2] Next, another embodiment of the electron beam inspection apparatus according to the present invention will be described with reference to FIG. As shown in FIG. 5, an electron beam inspection apparatus in which the objective lens 9 is installed above the detector 13 and the other configuration is the same as that of [Embodiment 1] of FIG. 1 will be described. The characteristic parts of the present embodiment will be described,
About the common part with [Embodiment 1] of FIG. 1, since it becomes complicated, it will not be described again.

As shown, the first secondary electrons 202 are:
Because the retarding electric field between the substrate 10 and the ground electrode 29 is rapidly accelerated to 3.5 kV to 11.5 kV, the angular distribution of the first secondary electrons 202 is
The primary secondary electrons 202 are concentrated near the normal direction of the irradiation point of the primary electron beam 201, and when colliding with the reflector 300, the spread of the first secondary electrons 202 is as small as about several mm in diameter. Therefore, almost all of the first secondary electrons are made to collide with the reflector, so that the detection efficiency hardly deteriorates.

According to [Embodiment 2], the second secondary electrons 203 can be detected with the same detection efficiency as that of [Embodiment 1], and the focal length of the objective lens 9 can be reduced. It is longer than that of [Embodiment 1], and the beam deflection of the primary electron beam can be increased, and the secondary electrons are not converged.

The embodiments of the present invention have been described above. The point is that the first secondary electrons 20 generated on the substrate 10 are formed.
2 and backscattered electrons 204, as in the prior art,
At least once, rather than being guided to 3
The electron beam inspection apparatus or method is configured to irradiate the reflection plate 300 other than the third 3 and guide the second secondary electrons 203 generated from the reflection plate 300 to a detection area of the detector 13 having a smaller area than the reflection plate 300. As a result, the secondary electrons 202 and the reflected electrons 204 generated on the substrate 10 are obtained.
Is detected at high speed and high efficiency with little deflection and no loss,
Any signal may be used as long as it effectively contributes to the image signal and the detection signal becomes a signal with good contrast.

For this purpose, the reflection plate 300 is provided with the substrate 10
The second secondary electrons 202 and the reflected electrons 204 are collided with high efficiency, and the second secondary electrons 20 and the reflected electrons 204 are directed toward the detector 13.
4 and reflected electrons are generated, and an electric field may be formed between the detector and the detector 13 so that desired electrons can be collected and captured near one point of the detection area.

Therefore, the numerical values described in the description of the above embodiment are merely examples. The detector 13 and the suction electrode 14 may be any one in which the position and applied voltage, the size of the detection area, the size of the opening diameter of the suction electrode 14 and the like are appropriately selected so as to collect desired electrons. The detector 13 may be any device provided that the center of the detection area of the detection surface is set near one point where desired electrons gather.

The reflecting plate 300 may have a spherical reflecting surface in cross section or a taper angle of 60 at the tip.
The upper and lower end portions may be formed into a conical shape or a flat surface of 45 degrees, which may be realized by simple processing. The reflection plate may be constituted by a flat plate having no angle change. Further, the material is not limited to those described in the above embodiment.
The captured electrons may be reflected electrons from the reflection plate 300, and the positional relationship and configuration of the reflection plate 300, the detector 13, and the like may be appropriately selected so as to capture the reflected electrons.

The shape of the suction electrode 14 is not limited to the shape of the above-described embodiment, and the center of the opening may be eccentric from the center axis of the suction electrode. Further, the configuration and arrangement of the electron gun and the electron optical system for extracting and promising electrons are not limited to this embodiment. The electron gun may be one that focuses only by the electrodes. The position of the condenser lens is not limited to this embodiment. Further, the potential of the illustrated grounded electrode is also positive within a range that can achieve the object of the present embodiment,
Alternatively, the potential may be negative. It is needless to say that all the numerical values described in the embodiments are enumerations, and that it is possible to implement with different numerical specifications.

[0055]

As described above in detail, according to the structure of the present invention, it is possible to detect secondary electrons or reflected electrons with high efficiency and high response speed by using a small area detection region. An electron beam that enables high-precision inspection of semiconductor wafers with non-conductive surfaces such as resist patterns and oxide films when inspecting for defects, foreign matter, residues, etc. of the same design pattern of the semiconductor device on the wafer using an electron beam An inspection device and a method thereof can be provided. With this inspection apparatus, it is possible to discover a defect that cannot be detected by the conventional apparatus, which has occurred in the manufacturing process, and reduce the defect rate of the semiconductor device by feeding back to the semiconductor process, thereby improving the reliability.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an electron beam inspection device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a general semiconductor device manufacturing process flow.

FIG. 3 is a partially enlarged configuration diagram of the electron beam inspection apparatus of FIG.

FIG. 4 is a partially enlarged view of the electron beam inspection apparatus of FIG.

FIG. 5 is an explanatory view of an electron beam inspection apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electron gun 2 ... Extraction electrode 3 ... Condenser lens 4 ... Blanking deflector 5 ... Scanning deflector 6 ... Aperture 7 ... Shield pipe 8 ... EXB deflector 9 ... Objective lens 10 ... Substrate to be inspected 11 ... XY Stage 12 Rotary stage 13 Secondary electron detector 14 Suction electrode 21 Preamplifier 22 AD converter 23 High voltage power supply 24 Scanning signal generator 25 Objective lens power supply 26 Optical sample height measuring instrument 27 Length monitor for position monitoring 28 ... Correction control circuit 29 ... Ground electrode 30a, b ... Image storage unit 31 ... Delay circuit 32 ... Monitor 33 ... Calculation unit 34 ... Defect determination unit 101 ... Electronic optical system 102 ... Sample chamber 103 ... Control Unit 104: Image processing system 201: Primary electron beam 202: First secondary electron 203: Second secondary electron 204: Reflected electron 300: Reflector

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hisaya Murakoshi 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Central Research Laboratory (72) Inventor Masaki Hasegawa 1-280 Higashi Koikekubo, Kokubunji, Tokyo, Japan Inside the Central Research Laboratory of Hitachi, Ltd. 72) Inventor Yasutoshi Usami 882 Ma, Hitachinaka-shi, Ibaraki Pref.

Claims (21)

[Claims] An electron source, an electron optical system that converges an electron beam from the electron source and scans and irradiates a sample on the sample, a sample stage that holds the sample, secondary charged particles from the sample, A deflector for deflecting reflected electrons, an electrode for generating an electric field for decelerating secondary charged particles and / or reflected electrons from the sample on the sample stage side of the deflector, and a secondary from the sample. A plate member for changing the direction of charged particles and / or reflected electrons, and a detector having an opening smaller than the plate member for detecting second charged particles and / or reflected particles from the plate member are provided. Electron beam inspection equipment. 2. An electron optical system including an electron source, an objective lens for converging an electron beam from the electron source to scan and irradiate a sample on a sample, a sample stage for holding the sample, and A deflector for deflecting secondary charged particles and / or reflected electrons, an electrode for generating an electric field for decelerating the secondary charged particles and / or reflected electrons on the sample stage side from the deflector, the deflector and the electrons A plate member for changing the direction of secondary charged particles and / or reflected electrons from a sample between the objective lens of the optical system, and a plate member for detecting second charged particles and / or reflected electrons from the plate member An electron beam inspection apparatus comprising a detector having a smaller opening. 3. An electron optical system including an electron source, an objective lens for converging an electron beam from the electron source, and scanning and irradiating a sample on the sample, a sample stage for holding the sample, and two components from the sample. A deflector for deflecting the secondary charged particles and / or reflected electrons; an electrode for generating an electric field for decelerating the secondary charged particles and / or reflected electrons on the sample stage side from the deflector; On the source side, a plate member for changing the direction of secondary charged particles and / or reflected electrons from the sample, and an opening smaller than the plate member for detecting second charged particles and / or reflected electrons from the plate member. An electron beam inspection apparatus, comprising: a detector having: 4. An electron beam inspection apparatus according to claim 1, wherein said detector is a semiconductor detector. 5. An electron beam inspection apparatus according to claim 4, wherein said semiconductor detector is of a PIN type. 6. An electron beam inspection apparatus according to claim 4, wherein said semiconductor detector is of a Schottky type. 7. An electron beam inspection apparatus according to claim 4, wherein said semiconductor detector is of an avalanche type. 8. The electron beam inspection apparatus according to claim 1, wherein a detection area of said semiconductor detector is 2
An electron beam inspection device characterized by being within 5 mm ² . 9. The electron beam inspection apparatus according to claim 1, wherein a hollow solid member having an end face having an opening is provided in front of a detection area of the detector so that the detector is included therein. An electron beam inspection apparatus, wherein a potential different from that of the detector is applied to the hollow solid member to control an electric field for accelerating and converging the second secondary charged particles and / or reflected particles. 10. The electron beam inspection apparatus according to claim 1, wherein said plate member is irradiated with said secondary charged particles and / or reflected particles generated from an irradiation object of said electron beam, and said irradiation is performed. An electron beam inspection apparatus characterized by using a material that generates a larger number of second secondary charged particles and reflected particles than the number of particles. 11. The electron beam inspection apparatus according to claim 1, wherein the plate member serves as a collision surface with secondary charged particles or reflected particles from the substrate, and irradiates the detector and the substrate with an electron beam. An electron beam inspection device having an opposing surface substantially at the center of the position. 12. The electron beam inspection apparatus according to claim 1, wherein said electron beam inspection apparatus is formed by a rotating body coaxial with a center axis of said electron beam instead of said plate member. 13. The electron beam inspection apparatus according to claim 1, wherein the plate member has a curved surface that collides with secondary charged particles or reflected particles from the substrate. Electron beam inspection equipment. 14. The electron beam inspection apparatus according to claim 1, wherein the collision surface has a shape such that normals of the collision surface converge near a center of a detection area of the detector. Electron beam inspection equipment. 15. An electron beam inspection apparatus according to claim 1, wherein said collision surface has a substantially spherical shape having a spherical center near a center of a detection area of said detector. apparatus. 16. An electron beam inspection apparatus according to claim 1, wherein the plate member has a plane of collision with a secondary charged particle or a reflected particle from the substrate. Electron beam inspection equipment. 17. An electron beam inspection apparatus according to claim 1, wherein said secondary charged particles are secondary electrons. 18. A charged particle source, an irradiation optical system for converging a charged particle beam from the charged particle source to scan and irradiate a sample, a holding table for holding the sample, and a secondary beam from the sample. A deflector that deflects the charged particles and / or the reflected particles, an electrode that generates an electric field that slows down the secondary charged particles and / or the reflected particles, and a direction of the secondary charged particles and / or the reflected particles from the sample. A charged particle beam application apparatus comprising: a plate member to be changed; and a detector having an opening smaller than the plate member for detecting second charged particles and / or reflected particles from the plate member. 19. A step of irradiating first and second regions of a substrate having a circuit pattern with a primary charged particle beam, the first charged particle beam, and the first and second regions of the substrate by irradiating the primary charged particle beam. Decelerating the secondary charged particles and / or reflected particles generated from the second region;
Alternatively, a deflecting step of deflecting the reflective particles, and a step of causing the secondary charged particles and / or reflected particles after the deflection to collide with the plate member to generate second secondary charged particles and / or reflected particles from the plate member And an accelerating and converging step of accelerating and converging the second secondary charged particles and / or reflecting particles by an electric field formed by the charged particle detector to which the voltage is applied with the plate member. Detecting a second secondary charged particle and / or a reflected particle with a detector having a smaller opening than the plate member, and forming images in first and second regions on the substrate from the detection signal An electron beam inspection method, comprising: an image forming step of performing an image forming step; and a comparing step of comparing images in the first and second regions formed as described above. 20. The electron beam inspection method according to claim 19, wherein, as the plate member, the secondary charged particles and / or reflected particles generated from the irradiation object by the electron beam are smaller than the number of the irradiated particles. An electron beam inspection method using a material that generates a large number of the second secondary charged particles and the reflective particles. 21. A step of irradiating an object to be irradiated with a primary charged particle beam, and secondary charged particles and reflective particles generated from the region of the object to be irradiated by the primary charged particle beam and the irradiation of the primary charged particle beam. A deceleration step of decelerating, and a deflection step of deflecting the secondary charged particles and / or reflection particles;
A step of causing the secondary charged particles and / or reflected particles after the deflection to collide with a solid member to generate second secondary charged particles and / or reflected particles from the solid member; and applying a voltage to the solid member. An accelerating and converging step of accelerating and converging the second secondary charged particles and / or reflected particles with an electric field formed by the detector; and the second secondary charged particles and / or reflected particles accelerating and converging. A detector having an opening smaller than the solid member, and an image forming step of forming an image in the region of the irradiation target from the detection signal. Particle beam application method.