JP2002310963A - Electron beam type inspection method and apparatus therefor and production method of semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam inspection method and an apparatus therefor which enable the inspecting of minute defects with higher reliability at a higher speed, by reducing charge up phenomenon caused when electron beams are made to irradiate onto an object for obtaining a signal with a high contrast exhibiting physical natures due to secondary electrons, reflected electrons or the like from the object. SOLUTION: In the electron beam type inspection method and apparatus therefor, electron beams are made to irradiate an object and physical changes caused in the object are detected with a sensor. From signals showing physical changes detected, the inspection or measuring of the object is carried out based on inspection conditions corresponding to the change up phenomenon in the surface of the object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of obtaining an image or a waveform representing the physical properties of an object such as a semiconductor wafer by using an electron beam to judge a defect, or obtaining information on the size or shape of a specific portion or manufacturing. The present invention relates to an electron beam inspection method and apparatus for inspecting by measuring conditions and the like, a semiconductor manufacturing method, and a manufacturing line thereof.

[0002]

2. Description of the Related Art A conventional electron beam inspection technique detects secondary electrons generated when an electron beam is irradiated under the same conditions, as described in, for example, Japanese Patent Application Laid-Open No. 5-258703. An image of secondary electrons is obtained by scanning a line, and a defect is determined based on the image.

[0003]

In the above prior art, the charge-up phenomenon that occurs when an object is irradiated with an electron beam has not been sufficiently considered.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to reduce a charge-up phenomenon that occurs when an object is irradiated with an electron beam and to reduce physical properties due to secondary electrons or reflected electrons from the object. It is an object of the present invention to provide an electron beam type inspection method and apparatus capable of obtaining a high-contrast signal expressing the above and inspecting minute defects at high speed with high reliability.

Another object of the present invention is to adjust inspection conditions to a charge-up phenomenon generated when an object is irradiated with an electron beam, and to adjust physical properties due to secondary electrons or reflected electrons from the object. It is an object of the present invention to provide an electron beam type inspection method and apparatus capable of performing an inspection or measurement based on an image signal expressing the above, so that a high-speed and minute defect can be inspected with high reliability.

Another object of the present invention is to provide an electron beam type inspection method and apparatus which enable highly reliable inspection of fine resist patterns and insulating film patterns which are easily charged.

Another object of the present invention is to provide a semiconductor manufacturing method and a manufacturing line for improving the yield by inspecting minute pattern defects on a semiconductor substrate such as a semiconductor wafer with high reliability. is there.

[0008]

In order to achieve the above object, the present invention controls an acceleration voltage of an electron beam and a potential gradient near an object. Is irradiated on the object, and a sensor detects a physical change generated from the object in accordance with the controlled potential gradient, and the object is detected based on a signal indicating the detected physical change. This is an electron beam inspection method characterized by performing inspection or measurement on an object.

Further, according to the present invention, an acceleration voltage of an electron beam and a potential gradient near an object are controlled, and an electron beam is irradiated on the object with the controlled acceleration voltage. A physical change generated from the object according to the potential gradient detected by the sensor, and a signal indicating the detected physical change is displayed on a display means. is there.

Further, according to the present invention, the acceleration voltage of the electron beam and the potential gradient near the object are controlled in accordance with the type of the cross-sectional structure on the surface of the object. Is irradiated on the object, a physical change generated from the object is detected by the sensor according to the controlled potential gradient, and the object is detected based on a signal indicating the detected physical change. This is an electron beam inspection method characterized by performing inspection or measurement on an object.

Further, according to the present invention, the acceleration voltage of the electron beam and the potential gradient near the object are controlled in accordance with at least the kind of material on the surface of the object, and the electron beam is controlled by the controlled acceleration voltage. Is irradiated on the object, a physical change generated from the object is detected by the sensor according to the controlled potential gradient, and the object is detected based on a signal indicating the detected physical change. This is an electron beam inspection method characterized by performing inspection or measurement on an object. Further, according to the present invention, the acceleration voltage of the electron beam and the potential gradient near the object are controlled in accordance with the change in the cross-sectional structure on the surface of the object, and the electron beam is irradiated with the controlled acceleration voltage. Irradiate the object, a physical change generated from the object according to the controlled potential gradient is detected by a sensor, and based on a signal indicating the detected physical change, the object is detected. An electron beam type inspection method characterized by performing inspection or measurement.

According to the present invention, the acceleration voltage of the electron beam and the potential gradient near the object are controlled in accordance with the type or change of the sectional structure in the area where the object is irradiated with the electron beam. The object is irradiated with an electron beam at the acceleration voltage, and a physical change generated from the object according to the controlled potential gradient is detected by a sensor. An electron beam inspection method characterized by performing inspection or measurement on an object based on a signal indicating a change.

Further, according to the present invention, an appropriate electron beam acceleration voltage and a potential gradient in the vicinity of the object corresponding to the charge-up phenomenon on the surface of the object are set, and the acceleration voltage is controlled to the set acceleration voltage. In this state, the object is irradiated with an electron beam, and a sensor detects a physical change generated from the object in accordance with the potential gradient controlled to the set potential gradient. An electron beam inspection method characterized by inspecting or measuring an object based on a signal indicating a physical change that has been made.

According to the present invention, there is provided an electron beam acceleration voltage and a potential gradient near an object corresponding to a charge-up phenomenon of the surface corresponding to the kind or change of the sectional structure on the surface of the object. Is set, and an electron beam is irradiated to the object in a state controlled to the set acceleration voltage, and is generated from the object according to the potential gradient controlled to the set potential gradient. An electron beam inspection method is characterized in that a physical change is detected by a sensor, and an inspection or measurement is performed on an object based on a signal indicating the detected physical change. Further, the invention is characterized in that, in the electron beam inspection method, the phenomenon of charge-up is regarded as secondary electron emission efficiency. Further, according to the present invention, in the electron beam inspection method, an acceleration voltage of the electron beam may be 0.3 KV to 5 KV.
V. Further, according to the invention, in the electron beam inspection method, a potential gradient near the object is 5 KV / mm or less.

The present invention also relates to an acceleration voltage of an electron beam on a sample, an electric field gradient on the sample, a beam current, a beam diameter, or an image detection frequency (the frequency of a clock for reading an image signal; Current density will change), or image size (by changing the scanning speed of the electron beam, the beam current density will change to change the image size), or precharge (by blowing an electron shower). Precharge on the object is controlled) or discharge (discharge on the object is controlled by spraying an ion shower), or a combination thereof to control the electron beam. An object is irradiated, a physical change generated from the object is detected by a sensor, and a signal indicating the detected physical change is provided. From an electron beam inspection method and performing inspection or measurement for the subject matter. Also, the present invention provides an acceleration voltage of an electron beam on a sample, or an electric field gradient on a sample, or a beam current, or a beam diameter, or an image detection frequency in accordance with the type or change of a cross-sectional structure on the surface of an object. (This is the frequency of the clock for reading the image signal, and the beam current density changes.) Or the image size (by changing the scanning speed of the electron beam, the beam current density changes and the image size changes). ), Or precharge (precharge on the object is controlled by spraying an electron shower), or discharge (discharge on the object is controlled by spraying an ion shower), or By controlling these combinations, the object beam is irradiated with the electron beam, and the physical change generated from the object is sensed. In detecting an electron beam inspection method and performing inspection or measurement for the object from the signal indicating the physical changes that this has been detected.

Further, according to the present invention, an object is irradiated with an electron beam, a physical change generated from the object is detected by a sensor, and an object is detected from a signal indicating the detected physical change. An electron beam inspection method for inspecting or measuring an object based on inspection conditions such as inspection standards (including judgment standards and measurement standards) corresponding to a charge-up phenomenon on the surface of the object. is there. Further, according to the present invention, an object is irradiated with an electron beam, a physical change generated from the object is detected by a sensor, and a signal indicating the detected physical change is used to detect the physical change of the object. Inspection or measurement of an object based on inspection conditions (including judgment standards and measurement standards) corresponding to the phenomenon of charge-up of the surface corresponding to the type or change of the cross-sectional structure of the surface. This is a characteristic electron beam inspection method. Further, according to the present invention, an object is irradiated with an electron beam, a physical change generated from the object is detected by a sensor, and a signal indicating the detected physical change is used to detect the physical change of the object. An electron beam inspection method characterized by extracting a structural feature of an object based on a feature extraction parameter corresponding to a charge-up phenomenon on a surface.

Further, according to the present invention, an object is irradiated with an electron beam, a physical change generated from the object is detected by a sensor, and an object is detected from a signal indicating the detected physical change. An electron beam inspection method for extracting a structural feature of an object based on a feature extraction parameter corresponding to a phenomenon of charge-up of the surface corresponding to a type or change of a cross-sectional structure of the surface of the object. It is. According to the present invention, a precharge (spraying an electron shower) or a discharge (spraying an ion shower) is applied to the surface of the object, and the object is irradiated with an electron beam to generate the electron beam. An electron beam inspection method is characterized in that a physical change to be detected is detected by a sensor, and an inspection or measurement is performed on an object from a signal indicating the detected physical change. According to the present invention, a precharge (spraying an electron shower) or a discharge (spraying an ion shower) is applied to the surface of the object, and the object is irradiated with an electron beam to generate the electron beam. An electron beam inspection method characterized in that a physical change to be detected is detected by a sensor, and a structural feature on the surface of the object is extracted from a signal indicating the detected physical change.

The present invention also provides an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. An objective lens, a potential control means for controlling an acceleration voltage of the electron beam and a potential gradient in the vicinity of the object, and irradiating the object with the electron beam at an acceleration voltage controlled by the potential control means. And a sensor that detects a physical change generated from the object according to the potential gradient controlled by the potential control means, and detects the physical change based on a signal indicating the physical change detected from the sensor. An electron beam type inspection apparatus comprising: an image processing means for inspecting or measuring an object. Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And, potential control means for controlling the acceleration voltage of the electron beam and a potential gradient in the vicinity of the object, and when irradiating the object with the electron beam at an acceleration voltage controlled by the potential control means, A sensor for detecting a physical change generated from the object according to the potential gradient controlled by the potential control means, and a display means for displaying a signal indicating the physical change detected from the sensor. An electron beam type inspection apparatus characterized in that:

The present invention also provides an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. An objective lens to be controlled, potential control means for controlling an acceleration voltage of the electron beam and a potential gradient in the vicinity of the object according to the type or change of the cross-sectional structure on the surface of the object, and controlled by the potential control means. A sensor for detecting a physical change generated from the object in accordance with the potential gradient controlled by the potential control means when the object is irradiated with an electron beam at the acceleration voltage, An electron beam inspection apparatus comprising: image processing means for inspecting or measuring an object based on a signal indicating a detected physical change.
Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And potential control means for controlling an acceleration voltage of the electron beam and a potential gradient near the object according to at least the kind or change of the material on the surface of the object; and an acceleration voltage controlled by the potential control means. A sensor for detecting a physical change generated from the object in accordance with the potential gradient controlled by the potential control means when the object is irradiated with an electron beam, and detecting the sensor from the sensor. An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object based on a signal indicating a physical change.

The present invention also provides an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. An objective lens to be controlled, potential control means for controlling an accelerating voltage of the electron beam and a potential gradient in the vicinity of the object in accordance with the type or change of the cross-sectional structure in the electron beam irradiation region on the object; When irradiating the object with the electron beam at the acceleration voltage controlled by the potential control means, a physical change generated from the object is detected according to the potential gradient controlled by the potential control means. An electron beam inspection apparatus comprising: a sensor; and image processing means for inspecting or measuring an object based on a signal indicating a physical change detected from the sensor. Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And potential control means for controlling an appropriate electron beam acceleration voltage corresponding to a charge-up phenomenon on the surface of the object and a potential gradient near the object, and an acceleration voltage controlled by the potential control means. A sensor for detecting a physical change generated from the object in accordance with the potential gradient controlled by the potential control means when the object is irradiated with an electron beam, and detecting the sensor from the sensor. An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object based on a signal indicating a physical change.

The present invention also provides an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. An objective lens to be controlled, and a proper acceleration voltage of an electron beam corresponding to a charge-up phenomenon of the surface corresponding to a kind or change of a cross-sectional structure of the surface of the object and a potential gradient in the vicinity of the object are controlled. A potential control unit, and a physics generated from the object according to a potential gradient controlled by the potential control unit when the object is irradiated with an electron beam at an acceleration voltage controlled by the potential control unit. Characterized by comprising: a sensor for detecting a physical change; and image processing means for inspecting or measuring an object based on a signal indicating a physical change detected from the sensor. An electron beam inspection apparatus. Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And controlling the acceleration voltage of the electron beam on the sample, or the electric field gradient on the sample, or the beam current, or the beam diameter, or the image detection frequency, or the image size, or the precharge, or the discharge, or a combination thereof. Control means, when irradiating the object with the electron beam,
A sensor for detecting a physical change generated from the object, and image processing means for inspecting or measuring the object from a signal indicating the physical change detected from the sensor, This is an electron beam type inspection apparatus.

According to another aspect of the present invention, there is provided an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. The objective lens and the accelerating voltage of the electron beam on the sample, or the electric field gradient on the sample, or the beam current, or the beam diameter, or the image detection frequency corresponding to the type or change of the cross-sectional structure on the surface of the object And control means for controlling image size, or precharge, or discharge, or a combination thereof, and detects a physical change generated from the object when the object is irradiated with an electron beam. An electron beam inspection apparatus, comprising: a sensor and image processing means for inspecting or measuring an object from a signal indicating a physical change detected from the sensor. That. The present invention also provides an electron beam source,
A beam deflector for deflecting the electron beam emitted from the electron beam source, an objective lens for focusing the electron beam emitted from the electron beam source on the object, and applying the electron beam to the object. A sensor for detecting a physical change generated from the object when irradiated to the object, an inspection condition creating means for creating an inspection condition corresponding to a phenomenon of charge-up on the surface of the object, and detection from the sensor. An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object based on an inspection condition created by the inspection condition creation unit from a signal indicating a physical change to be performed. It is.

The present invention also provides an electron beam source, a beam deflector for deflecting the electron beam emitted from the electron beam source, and focusing the electron beam emitted from the electron beam source on an object. An objective lens, a sensor for detecting a physical change generated from the object when the object is irradiated with an electron beam, and a type or change of a cross-sectional structure on the surface of the object. An inspection condition creating means for creating an inspection condition corresponding to the phenomenon of charge-up on the surface; and a test object created from a signal indicating a physical change detected from the sensor based on the inspection condition created by the inspection condition creating means. An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object. Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. Creates a sensor that detects physical changes that occur from an object when the object is irradiated with an electron beam, and creates feature extraction parameters corresponding to the phenomenon of charge-up on the surface of the object. Image processing for extracting a structural feature of an object based on a feature extraction parameter created by a preceding feature extraction parameter creating unit from a signal indicating a physical change detected from the sensor. And an electron beam type inspection apparatus.

According to the present invention, an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an electron beam emitted from the electron beam source are focused on an object. An objective lens to be caused, a means for applying a precharge or a discharge to the surface of the object, and a sensor for detecting a physical change generated from the object when irradiating the object with an electron beam, An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object based on an inspection condition from a signal indicating a physical change detected from the sensor. Further, the present invention provides an electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. Means for precharging or discharging the surface of the object, a sensor for detecting a physical change generated from the object when the object is irradiated with an electron beam, and An electron beam inspection apparatus comprising: an image processing unit that extracts a structural feature of an object based on a feature extraction parameter from a signal indicating a detected physical change. According to another aspect of the present invention, there is provided a semiconductor manufacturing line including a plurality of processing apparatuses for processing a substrate and a control apparatus for controlling the plurality of processing apparatuses. An electron beam inspection apparatus for inspecting based on an image signal obtained by irradiation is provided, and the processing apparatus is controlled by the control apparatus based on an inspection result obtained from the electron beam inspection apparatus. This is a semiconductor production line.

Further, according to the present invention, the acceleration voltage of the electron beam and the potential gradient near the object are controlled, and the electron beam is irradiated on the object with the controlled acceleration voltage. Manufacturing a semiconductor substrate by detecting a physical change generated from the semiconductor substrate according to the potential gradient by a sensor and performing inspection or measurement on the semiconductor substrate based on a signal indicating the detected physical change. A semiconductor manufacturing method characterized by the following. The present invention also provides an acceleration voltage of the electron beam on the sample, or an electric field gradient on the sample,
Or beam current, or beam diameter, or image detection frequency,
Or controlling the image size, or precharge, or discharge, or a combination thereof, irradiating the semiconductor substrate with an electron beam, detecting a physical change generated from the semiconductor substrate with a sensor, and detecting the detected physical change. A semiconductor manufacturing method characterized in that a semiconductor substrate is manufactured by inspecting or measuring a semiconductor substrate from a signal indicating a physical change. Further, according to the present invention, a semiconductor substrate is irradiated with an electron beam, a physical change generated from the semiconductor substrate is detected by a sensor, and a charge on the surface of the semiconductor substrate is detected from a signal indicating the detected physical change. A semiconductor manufacturing method characterized by performing inspection or measurement on a semiconductor substrate based on an inspection condition corresponding to an up phenomenon and manufacturing the semiconductor substrate. Further, according to the present invention, in the semiconductor manufacturing method, the inspection or measurement result is analyzed and fed back to a predetermined process.

The present invention is also a method for inspecting a pattern on a sample by irradiating an electron beam on a sample having a pattern formed on its surface and detecting secondary electrons or reflected electrons generated from the sample, An electron beam type inspection method characterized by controlling an accelerating voltage of an electron beam and a potential gradient near a surface of the sample in accordance with a material in a region of the sample irradiated with the electron beam. Further, according to the present invention, in the electron beam inspection method, the accelerating voltage of the electron beam is controlled based on a difference between a secondary electron emission rate of the pattern and a secondary electron emission rate of a portion other than the pattern. It is characterized by the following. Further, the invention is characterized in that, in the electron beam inspection method, a potential gradient near the sample surface is controlled based on a secondary electron emission rate from the pattern. Further, the present invention is a method for inspecting a pattern on a sample by irradiating an electron beam on a sample having a pattern formed on its surface and detecting secondary electrons or reflected electrons generated from the sample, The accelerating voltage of the electron beam and the potential gradient near the sample surface are controlled according to the material in the region where the electron beam is irradiated, and the charge accumulated on the sample surface is neutralized, and the detected secondary electrons or An electron beam inspection method characterized by displaying an image of reflected electrons on a screen.

As described above, according to the present invention, the charge-up phenomenon that occurs when an object is irradiated with an electron beam is reduced, and the physical properties due to secondary electrons or reflected electrons from the object are reduced. Thus, a high-contrast signal indicating the above can be obtained, and a fine defect can be inspected at high speed with high reliability.
Further, according to the present invention, an image signal expressing physical properties due to secondary electrons or reflected electrons from an object by adapting inspection conditions to a charge-up phenomenon generated when an electron beam is irradiated onto the object. Inspection or measurement can be performed on the basis of high-speed and high-reliability inspection of fine defects.

Further, according to the present invention, a fine resist pattern or an insulating film pattern which is easily charged can be inspected with high reliability. Further, according to the present invention, a fine pattern defect on a semiconductor substrate such as a semiconductor wafer can be inspected with high reliability to improve the yield. Further, according to the present invention, a fine defect can be inspected at high speed with high reliability, and as a result, a fine pattern defect on a wafer having a fine pattern line width can be inspected in a production line. .

[0029]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a pattern inspection method for inspecting a pattern size and a defect on an object such as a semiconductor wafer using an electron beam according to the present invention, and a semiconductor wafer manufacturing method. It will be described using FIG. A case where a semiconductor wafer is used as an object will be described. The same holds for other objects such as a photomask, a thin-film multilayer substrate, a printed wiring board, and a TFT substrate.

First, a description will be given of an embodiment in which a pattern on an object such as a semiconductor wafer is detected using a material A1 and a material B2 when the pattern on the object is detected using an electron beam according to the present invention. The object has a three-dimensional cross-sectional structure made of, for example, a material A1 on a base (lower) and a material B2 on an upper part. When an object having such a three-dimensional cross-sectional structure made of different materials is irradiated with an electron beam, the contrast may be almost eliminated at a specific acceleration voltage. This will be described with reference to FIG. FIG.
Shows the relationship between the acceleration voltage E of the material A1 and the material B2 and the secondary electron emission efficiency η. From this figure, it can be seen that the acceleration voltage E
When b is used, the secondary electron emission efficiency η of the material A1 and the material B2 is greatly different, and the secondary electron images obtained by the material A1 and the material B2 have sufficient contrast as shown in FIG. Yes, inspection including measurement (inspection of dimensions or defects) is possible. On the other hand, when the specific acceleration voltage Ea is used, the secondary electron emission efficiencies of the material A1 and the material B2 are equal, and the contrast of the secondary electron images obtained by the material A1 and the material B2 is almost eliminated. As shown in b), an image having almost no contrast is obtained, and an inspection including a measurement (inspection of dimensions or defects) becomes impossible. The specific acceleration voltage Ea differs depending on the material, and a suitable acceleration voltage differs depending on the material of the object.

Next, an embodiment in which a pattern on an object such as a semiconductor wafer is detected using a material A3 and a material B4 when detecting a pattern on the object using an electron beam according to the present invention will be described. This will be described with reference to FIGS. 3, 4, 5, and 6. That is, as shown in FIG. 3, an electron beam is applied to an object having a three-dimensional cross-sectional structure including a material A3 (for example, a wiring pattern) on the upper part and a material B4 (for example, an interlayer insulating layer) on the base (lower part). When the material B4 is irradiated, the material B4 is charged up negatively, that is, the secondary electron emission efficiency η is 1 or less. Under the condition that the material A3 is positively charged up, that is, the secondary electron emission efficiency η is 1 or more (secondary electrons substantially equivalent to the irradiated electron beam are emitted). Meaning). In case of light charge up,
As shown in (a), the defect 7 of the material A3 as well as the defect of the material A3 is detected to be bright, the defect B4 of the material A4 is detected to be dark, and the defect 7 of the material A3 originally protruding to the portion of the material B4 is also detected to be bright.

However, when charge-up is severe,
Since the material A3 located at the upper portion has a positive charge-up, the secondary electrons 6 from the defect 7 of the material A3 located at the lower portion are attracted to the positively charged material A3 to be secondary electrons. It is not detected by the detector 16 (11). For this reason, as shown in FIG. 4B or FIG. 4C, a small detection is performed, or detection is not possible at all. Similarly, since information on the inclined portion of the material B4 is lost, FIG.
As shown in (a), the pattern dimension to be detected is
As shown in FIG. 5B, the detection is small.

Further, this phenomenon depends on relaxation of charge-up of the object, that is, diffusion speed of positively or negatively charged charges. In the case where charge-up is eased quickly, the phenomenon is complicated, the dependence of the electron beam on the scanning direction is increased, and information to be lost differs depending on the X and Y scanning directions. As a result, an image as shown in FIGS. 6B and 6C is obtained. In other words, when scanning in the X direction, the effect is likely to appear near the pattern edge in the X direction, and when scanning in the Y direction, the effect is likely to appear near the pattern edge in the Y direction. The diffusion differs depending on the conductivity of the underlying pattern (material B). When the conductivity is large, the diffusion is very fast, and the charge-up is eased quickly. Next, when detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention, a third embodiment in which the pattern of the object is made of a material A8 and a material B9 will be described. This will be described with reference to FIGS. That is, as shown in FIG. 7, when an object having a three-dimensional cross-sectional structure composed of the material B9 on the base and the material A8 on the base is irradiated with the electron beam 5, the condition that the material B9 is positively charged up. That is, the secondary electron emission efficiency η is 1
In the above, it is assumed that the condition under which the material A8 is negatively charged up, that is, the secondary electron emission efficiency η is 1 or less. If the degree of charge-up is light, material A as shown in FIG.
8 is dark and material B9 is bright. However, when the charge-up is severe, an electric field is formed due to the influence of the charge-up. The electric field formed in the periphery is shown in the figure. When the 0 V equipotential line 73 and the negative equipotential line 72 are formed and the electron beam 5 is irradiated on the material A8 to generate the secondary electrons 71, The next electron 71 is repelled by a negative electric field and pushed back. For this reason, the secondary electrons 71 from the material A8 cannot reach the secondary electron detector 16 (11), and information about the base is lost. As a result, FIG.
As shown in (1), a portion where the pattern density is high is to be detected as a bright portion, while a dark portion is detected, and a pseudo pattern is generated at a boundary where the pattern density is different.

In any case, when charge-up occurs, the secondary electron emission efficiency η changes due to the charge-up of itself. Therefore, the first detection image and the plurality of detection images change as shown in FIG. Therefore, in the present invention, first, in the object 20, at least the pattern (material A) on the upper portion is prevented from being charged as much as possible, that is, the degree of charge-up is reduced, and the pattern (material A) is further reduced. The purpose of the present invention is to optimize inspection conditions including measurement so that an appropriate contrast ρ can be obtained (as high as possible) from the pattern and the minute interval (material B) of the pattern so that an image can be detected. That is, as shown in FIG. 1, at least an upper pattern (material A or material A) having a characteristic of the secondary electron emission efficiency η with respect to the acceleration voltage E to the irradiated electron beam in each of the materials A and B, as shown in FIG. In B), charge-up is prevented from occurring as much as possible (the secondary electron emission efficiency η from the upper pattern (material A or B) is within a small allowable value of about 1), and an appropriate contrast ρ is obtained.
(The secondary electron emission efficiency η from the lower material B or A is set to a predetermined range (for example, 0.7 to
(B) (c) or FIG. 5 (b) or (b) by making the condition that the difference from the secondary electron emission efficiency η of the material A or B in the upper part is the largest. FIG.
Instead of the image signal greatly affected by the charge-up as shown in (b), the influence of the charge-up is reduced as shown in FIG. 4 (a), FIG. 5 (a) or FIG. The image signal having obtained the contrast ρ can be detected by the sensor 11. Therefore, in order to minimize the charge-up of at least the upper pattern (material A or B) in the object 20, a method of reducing the amount of electron beams accumulated on the object 20. And a method of irradiating an electron shower or an ion shower for neutralization.

As a method for reducing the amount of the electron beam accumulated on the object 20, the object 20 or the object 2
A suitable acceleration voltage (E ₀₎ for accelerating the electron beam emitted from the electron beam source 14 between the electron beam source 14 and a voltage applying means 19 such as a grid for passing an electron beam provided on the top of the electron beam.
−E ₂ ), and a potential gradient α on the object between the voltage applying means 19 such as a grid and the object 20.
By providing an appropriate potential difference (E ₀ −E ₁ ) proportional to However, the phenomenon of charging up the upper pattern changes when the constituent material (material) and cross-sectional structure of the upper pattern change. Therefore, the constituent material (material) and the cross-sectional structure (upper constituent material (material) of the upper pattern
In particular, the acceleration voltage E of the electron beam to the object and the amount of Needs to be set appropriately. That is, the charge is increased by the constituent material (material) of the upper pattern and the cross-sectional structure (including the shape (including line width and density) and the thickness of the pattern and the constituent material (material) of the lower part) of the object. This is because the phenomenon changes and the secondary electron emission efficiency η changes. FIG. 1 shows the secondary electron emission efficiency η with respect to the acceleration voltage E when the material is changed.
Is shown.

In particular, since the phenomenon of charge-up relaxation (diffusion of charged charges) occurs especially in the upper pattern, the scanning direction of the electron beam in the X direction and the Y direction is as shown in FIGS. 6 (b) and 6 (c). As shown, a difference appears in the image signal detected by the sensor 11. Therefore, the image signal detected by the sensor 11 when the scanning direction of the electron beam is in the X direction and the image signal detected by the sensor 11 when the scanning direction of the electron beam is in the Y direction with respect to the object 20 are compared. In particular, it is necessary to properly set the acceleration voltage E of the electron beam to the object and the potential gradient α on the object so as to reduce the difference between them as much as possible. Also, in order to inspect the pattern at the top for dimensions or defects,
In particular, the acceleration voltage E of the electron beam to the object and the potential gradient α on the object need to be appropriately set so that the upper pattern can be detected with an appropriate contrast ρ as an image signal detected by the sensor 11. There is.

As will be described later, the potential difference (E₀−
E_Two) Indicates the potential difference from the electron beam source 14 to the object 20.
This is the acceleration voltage E shown in FIG. This potential
Difference (E ₀-E_Two), That is, by controlling the acceleration voltage E
In particular, as shown in FIG.
Quality A or B)
Can be changed. On the other hand, the object 2
0 and a potential difference (E
₀-E₁) Is almost proportional to the potential gradient α on the object surface.
Will be. Therefore, the potential difference (E₀-E₁), The potential gradient
By controlling the arrangement α, as shown in FIG.
Char to the pattern (Material A or B) located at the top
Changing the secondary electron emission efficiency η by changing the zip-up phenomenon
Can be. Potential gradient α is positive, that is, secondary electrons are decelerated
In this case, secondary electrons are difficult to be emitted,
The output efficiency η will decrease. On the other hand, the potential gradient α
Negative, that is, secondary electrons are emitted when secondary electrons are accelerated
Increase secondary electron emission efficiency η
become. In addition, the beam current or beam on the object
Diameter or image detection frequency (clock for reading image signal
And the beam current density will change.
You. ) Or image size (change the scanning speed of the electron beam
Changes the beam current density and image dimensions.
I will understand. ) Also controls the char
Optimize the detected image signal by changing the
Can be.

As described above, depending on the material and cross-sectional structure of the pattern of the object (including the shape of the pattern (including the line width and density), the thickness, and the relationship with the lower constituent material (material), etc.), For example, by controlling two parameters (the acceleration voltage E of the electron beam to the object and the potential gradient α on the object) in a predetermined relationship, the secondary electron emission efficiency η from the pattern located particularly above Is within an allowable range (approximately 1) with respect to 1, the charge-up occurring in the upper pattern is reduced to a value less than a desired value so as to almost eliminate the charge-up, and the secondary electron emission efficiency from the lower material is reduced. η determined range (for example, 0.7 to 1.2)
The charge-up is also reduced as much as possible for the material located at the lower part by making it inside, and the difference of the secondary electron emission efficiency η between the pattern located at the upper part and the pattern not located at the upper part is minimized. By increasing the size, the contrast ρ can be optimized, and as a result, an image having a sufficient contrast can be detected by the sensor 11 under a condition that does not cause charge-up particularly for a pattern located on the upper portion, and the line width can be detected. Inspection of dimensions and defects in miniaturized patterns can be realized with high reliability. That is, various factors are considered in accordance with the material and cross-sectional structure of the pattern of the object (including the shape of the pattern (including the line width and density), the thickness, and the relationship with the lower constituent material (material)). Inspection of dimensions and defects in fine patterns on semiconductor wafers, etc., whose line width has been reduced by optimizing the acceleration voltage of the electron beam to the object and the potential gradient α on the object It can be realized by. Even in a chip formed on a semiconductor wafer, when the material and cross-sectional structure of the pattern (including the pattern shape (including line width and density), the thickness, and the relationship with the lower constituent material (material)) change Therefore, it is necessary to control two parameters (acceleration voltage E of the electron beam to the object and potential gradient α on the object) in a predetermined relationship. Naturally, if the material or cross-sectional structure of the surface of the object to be inspected for dimensions or defects changes, two parameters (acceleration voltage E of electron beam to the object and potential gradient α on the object) are used. Must be controlled in a predetermined relationship. In any case, two parameters suitable for the material of the surface pattern and the cross-sectional structure (the acceleration voltage E of the electron beam to the object and the object before the inspection of the pattern on the surface of the object). It suffices if the condition of the above potential gradient α) can be set.

Even if the accelerating voltage E of the electron beam to the object and the potential gradient α on the object are optimized, the charge-up phenomenon and the charge-up relaxation phenomenon (especially the charge-up phenomenon) particularly in the pattern on the upper part. Charge diffusion phenomenon) cannot be almost eliminated. Therefore, when performing, for example, a defect inspection on an upper pattern based on an image signal detected by the sensor 11, a parameter for extracting a structural feature amount as a defect, a defect determination criterion (inspection criterion) and the like are compared. In consideration of the charge-up phenomenon and the relaxation phenomenon of the charge-up (diffusion phenomenon of the charged charge) to the pattern on the upper part, the error caused by the charge-up phenomenon and the relaxation phenomenon of the charge-up to the upper pattern is determined. Inspection of dimensions and defects in a fine pattern on a semiconductor wafer or the like having a reduced line width by eliminating detection can be realized with high reliability. If the material and the cross-sectional shape (including the line width and density) of the pattern of the object change, the charge-up phenomenon and the charge-up relaxation phenomenon (diffusion phenomenon of the charged charge) to the pattern on the upper part also change. Depending on the material and cross-sectional shape (including the line width and density) of the pattern of the object, a parameter for extracting a structural feature amount as a defect, a defect determination criterion for comparison and the like may be selected. It also detects the charge-up phenomenon and the charge-up relaxation phenomenon (diffusion phenomenon of charged charge) in the pattern on the upper part, and responds to the detected charge-up phenomenon and the charge-up relaxation phenomenon in the upper pattern. A parameter for extracting a structural feature amount as a defect, a defect determination criterion for comparison and the like may be selected.

Next, a semiconductor wafer is formed using the electron beam according to the present invention.
A system for detecting patterns on an object such as eha
One embodiment will be described with reference to FIG. Immediately
In this system, the potential from the ground is E_TwoIs
An electron beam source 14 for generating a sagittal beam is scanned by an electron beam.
And a beam deflector 15 for imaging.
An objective lens 18 for forming an image on an object 20;
Between the object 18 and the object 20 such as a semiconductor wafer.
The potential from the grid is E₁Potential application to grids
The means 19 and the object 20 are mounted, and the object 20 is grouped.
E from the land₀XY stage
The sample stage 21 and secondary electrons generated in the object 20
A sensor 11 for detecting a physical change such as
A height detection sensor 13 for detecting the height of the object 20;
The potential E of each part that determines the acceleration voltage of the electron beam to the object 20
₀, E₁, E_TwoPotential control unit 23 for controlling the height
Outgoing sensor 13 Objective lens based on height of object 20
Focus position controller 22 for controlling the focus position by controlling 18
And the physical properties of the object detected by the sensor 11
Converts a waveform or image signal representing
A / D conversion unit 24 and the A / D conversion unit 24
Image processing on the digital signal
An image processing unit 25 for performing an inspection including a dimension measurement of the turn;
Process number indicating the surface cross-sectional structure of the object 20 and the object
For example, from the A / D conversion unit 24
Inspection conditions (for example,
Two parameters (potential difference (E₀-E_TwoGiven as)
Acceleration voltage E and potential difference (E
₀-E₁Object) given in a relationship that is approximately proportional as
Condition of the upper potential gradient α) or the pattern
Charge-up phenomenon and charge-up relaxation phenomenon (charging
Inspection conditions to optimize the charge diffusion phenomenon))
And the inspection conditions (for example, the two parameters described above).
(Potential difference (E₀-E_TwoTo the object given as
The acceleration voltage E and the potential difference (E₀-E ₁)
Potential gradient α) on the object given by a proportional relationship
Condition or charge up to the pattern on top
Elephant and charge-up relaxation (diffusion of charged charge
Elephant) etc. are replaced with step numbers indicating the surface cross-sectional structure of the object 20.
A group of objects by specifying the number and the object number
For each object (for each object having the same surface structure)
Condition setting unit 28 for setting inspection conditions by using
A scanning controller 47 for controlling the director 15 and a sample stage 21.
And a stage control unit 50 for controlling
It comprises a body control unit 26.

As the sequence of this system, three shown in FIG. 14 can be considered. The first method is based on an inspection condition (for example, the two parameters (potential difference (E ₀ −
The acceleration voltage E of the electron beam to the object given as E ₂ ) and the condition of the potential gradient α) on the object given in a substantially proportional relationship as the potential difference (E ₀ −E ₁ ) are set. After loading the target object 20 in step 31a and aligning the target object 20 in step 32a, the inspection condition optimization unit 27 determines the physical condition of the target object 20 detected by the sensor 11 in step 33a. The relationship between the charge-up phenomenon based on the secondary electron emission efficiency η extracted based on the characteristic waveform or image signal and the charge-up relaxation phenomenon based on the change in the signal detected by multiple scanning of the electron beam In step 34a, the inspection condition setting unit 28 determines the optimized inspection conditions stored in the inspection condition optimization unit 27. Desired inspection conditions are stored and set for the case, and in step 35a, the overall control unit 26 uses the potential control unit 23 based on the desired inspection conditions set in the inspection condition setting unit 28 to set the potentials E ₀ and E _{1 of the respective} units. , E ₂ , the electron beam emitted from the electron beam source 14 is imaged on the object 20 by the objective lens 18, scanned by the beam deflector 15, and the secondary electrons generated in the object 20 are controlled. And a physical change such as backscattered electrons are detected by the sensor 11, and a waveform or image signal representing the detected physical property of the object is obtained. Inspection for defects and the like is performed, and the object 20 is unloaded in step 36a.

In the second method, before the inspection, inspection conditions (for example, the acceleration voltage E and the potential difference (E ₀ ) of the electron beam to the object given to the _two parameters (potential difference (E ₀ -E ₂ ) given above) -E ₁ ) by setting a potential gradient α) on the object, which is given in a substantially proportional relationship, in advance for each group of objects (for each object having the same surface structure) in step 31b. In step 32b, each object having a different surface structure is loaded, and the object is positioned in step 32b. Then, in step 33b, the inspection condition optimizing unit 27 uses the sensor 11 for each object having the same surface structure. A charge-up phenomenon based on a secondary electron emission efficiency η extracted based on a waveform or image signal representing a physical property of the detected object 20 or a plurality of scans of an electron beam Inspection conditions are optimized and stored based on the relationship between the phenomena of charge-up mitigation based on the change in the signal detected in step 36b, and each object is unloaded in step 36b.
0 is loaded in step 31c and the object is aligned in step 32c, and then in step 34c, the inspection condition setting unit 28 determines whether each object having the same surface structure stored in the inspection condition optimization unit 27 has A desired inspection condition corresponding to the object to be actually inspected is selected and stored and set from the appropriate inspection condition group, and in step 35c, the overall control unit 26 selects and sets the desired inspection condition selected and set by the inspection condition setting unit 28. The potentials E ₀ , E ₁ , and E ₂ of the respective parts are controlled by the potential control unit 23 based on the inspection conditions described above, and the electron beam emitted from the electron beam source 14 is imaged on the object 20 by the objective lens 18. The beam is deflected by the beam deflector 15, and physical changes such as secondary electrons and reflected electrons generated in the object 20 are detected by the sensor 11. It inspects such dimensions or defects in the image processing unit 25 based on this signal to obtain a signal having a waveform or image Genwa the physical properties, for unloading the subject matter 20 in step 36c.

In the third method, the relationship between the charge-up phenomenon and the charge-up relaxation phenomenon based on the secondary electron emission efficiency η, which can be theoretically or empirically calculated from the information on the object before inspection in step 37d. Based on the inspection conditions (for example, the two parameters (potential difference (E ₀ −
The acceleration voltage E of the electron beam to the object given as E ₂ ) and the potential gradient α) on the object given in a substantially proportional relationship as the potential difference (E ₀ −E ₁ ) are supplied to the inspection condition setting unit 28. After the object 20 to be actually inspected is loaded in step 31d and the object is aligned in step 32d, the object 20 is stored and set in advance in the inspection condition setting unit 28 in step 34d. Storing desired inspection conditions from the inspection conditions
In step 35d, the overall control unit 26 controls the potentials E ₀ , E ₁ , and E ₂ of the respective units by the potential control unit 23 based on the set desired inspection conditions, and applies the electron beam emitted from the electron beam source 14 to the objective. An image is formed on the object 20 by the lens 18 and scanned by the beam deflector 15.
The sensor 11 detects physical changes such as secondary electrons and reflected electrons generated by the sensor 11, obtains a waveform or image signal representing the detected physical properties of the object, and obtains an image based on the signal. Inspection of dimensions or defects is performed in the processing unit 25, and the object 20 is unloaded in step 36d. Note that the setting of the inspection condition in the inspection condition setting unit 28 in step 37d may be performed after the loading if it is before the inspection.

As the inspection conditions, in addition to the above two parameters, the beam current and beam diameter on the object, the image detection frequency (the frequency of the clock for reading the image signal, and the beam current density changes) .),
An image size (an image size changes due to a change in beam current density by changing the scanning speed of the electron beam) can be considered.

Next, the inspection condition which is a component of these systems
Of inspection conditions and setting of inspection conditions based on information on the target object
The setting of the converted inspection condition will be described. That is, FIG.
And the relationship shown in FIG. 10 may be determined in advance. Suffered
In the sectional structure of the elephant 20 (for example, materials A and B),
The acceleration voltage (E = E) between the sagittal source 14 and the object 20 ₀
-E_Two) And the potential proportional to the potential gradient α on the object
Difference (E₀-E₁) Is related to the secondary electron emission efficiency η.
That is, these relation tables are created
If there is a charge up for the upper pattern
Within the range (secondary power from upper pattern)
The lower emission rate η is within a small tolerance around 1)
Charge up as much as possible (lower
Large tolerance of secondary electron emission rate η from pattern around 1
Within the value (for example, 0.7 to 1.2) and the upper pattern
Between the brightness of the image signal and the lower pattern
The proper contrast ρ shown (two from the top pattern)
Secondary electron emission rate η and secondary electron emission rate η from lower pattern
And given by the difference ) Can be selected.

That is, in FIG. 11, the secondary electron emission efficiency (indicated by a solid line) η from the upper pattern (material A) and the secondary electron emission efficiency (indicated by the dashed line) η from the lower pattern (material B) are shown in FIG. Is selected so that the difference (contrast .rho.) Between them becomes large, and then the secondary electron emission rate .eta. From the upper pattern (material A) falls within a small allowable value around 1. The potential difference (E ₀₎ proportional to the potential gradient α
−E ₁ ). In this case, if the secondary electron emission rate η from the lower pattern (material B) does not fall within a large allowable value of about 1, the acceleration voltage Ec is finely adjusted to obtain an appropriate value. Inspection conditions can be selected.

In FIG. 12, the secondary electron emission efficiency (indicated by a dashed line) η from the upper pattern (material B) and the secondary electron emission efficiency (indicated by the solid line) η from the lower pattern (material A) are shown in FIG. Is selected so that the difference (contrast .rho.) Between them becomes large, and then the secondary electron emission rate .eta. From the upper pattern (material B) falls within a small allowable value of about 1. The potential difference (E ₀₎ proportional to the potential gradient α
−E ₁ ), and when the secondary electron emission rate η from the lower pattern (material A) does not fall within a large allowable value of about 1, the acceleration voltage Ec is finely adjusted to the acceleration voltage Ed. This makes it possible to select appropriate inspection conditions.

FIG. 15 shows an inspection condition optimizing unit 27 (27).
a, 27b) and a specific configuration showing an embodiment of the inspection condition setting unit 28. Reference numeral 131 denotes a CPU; 132, a ROM storing a test condition optimization processing program;
Reference numeral 33 denotes an image memory for storing digital images and the like obtained from the C / D converter 24, and 134 an R for storing various data, information on optimized inspection conditions, set inspection conditions, and the like.
AM, 135 are input means formed by a keyboard, a mouse or the like, 136 is display means, such as a display, and 137 is C
An external storage device for storing information on the object such as AD data, 138 is design information composed of CAD data and the like obtained from a design system, 139 to 144 are interface (I / F) circuits, and 145 is a bus connecting each of them. It is.

Each unit shown in FIG. 13 is initialized by a command from the overall control unit 26, and the stage control unit 50 is controlled to move the object 20 to a predetermined or user-specified location. The potentials E ₀ , E ₁ , and E ₂ determined in advance are set by the potential control unit 23 in accordance with a command from the overall control unit 26, and the focus position determined by the conditions is set by the focus position control unit 22. The electron beam emitted from the source 14 is irradiated on the object 20 via the objective lens 18 while being scanned by the beam deflector 15 under the control of the scanning control unit 47, and generated by the sensor 11 on the object 20. A physical change such as a secondary electron or a reflected electron is detected to detect a waveform or image signal representing the physical properties of the object, and the A / D converter 24 converts the signal into a digital image signal. The inspection condition optimization section 27 stores the digital image signal converted by the A / D conversion section 24 in the image memory 133, displays the stored digital image signal on the display 136, and displays the displayed digital image signal. 2, the user designates a pattern (material A or B) on the upper part of a region having a pattern repetition as shown in FIGS. 2, 4, 5, 6, and 8 using the input means 135 or the like. Then, based on the designation, the CPU 131 extracts the contour of the pattern (material A or B) from the detected digital image signal and stores the shape of the pattern (material A or B) in, for example, an external storage device (dictionary). ) 137 and the like and the object 2
The amount (for example, dose) of the electron beam irradiated on the zero is also stored in, for example, the RAM 134 using the input means 135 or the like.
In addition, about the shape of a pattern (material A or B),
There is no need to extract and find the contour of the pattern (material A or B) from the detected digital image signal.
An area can be designated based on the design information obtained as the CAD data 138. CAD data 138
Since information (particularly, shape (including line width and interval), thickness, etc.) relating to the upper pattern can be obtained from, appropriate inspection conditions can be selected using this information.

Next, an electron beam is irradiated on the object 20.
New areas that have not been charged up
For installation, based on the control of the stage control unit 50
While scanning the stage of the sample table 21,
Each potential E for each returned pattern area₀, E₁, E
_TwoIs controlled by the potential control unit 23 at a constant pitch, for example.
The acceleration voltage (E) between the electron beam source 14 and the object 20₀−
E_Two) And the potential difference proportional to the potential gradient α on the object
(E₀-E₁) Is controlled and designated on the object 20.
Secondary power generated from the area of each repeated pattern
Waveform or image showing physical changes such as electrons and backscattered electrons
Is detected by the sensor 11 and the A / D converter 24
Is converted to a digital image signal and stored in the image memory 133.
Each of the potentials E changed and controlled by the potential control unit 23₀, E₁, E
_TwoIs received via the overall control unit 26 and, for example, R
Store it in AM134. The CPU 131 executes the above image memo
Out of the digital image signal stored in the
Pattern stored (registered) in storage device (dictionary) 137
(Material A or B) at a location that matches the external shape
Secondary electron emission rate η and contrast ρ (image material)
Digitizer corresponding to secondary electron emission rate η by A and material B
It is given by the difference in brightness of the image signal. ) Etc.
The result is stored in the RAM 134, for example. CPU 13
For example, among the image quality stored in the RAM 134,
The electron emission rate η is within a small allowable value of around 1.
Charge-up as much as possible)
Each potential E having the highest image contrast ρ₀, E₁, E_TwoSeeking
Thus, each of the obtained potentials E₀, E ₁, E_TwoThe proper inspection clause
Inspection condition storage unit (RAM 134 or external storage
Device 137). Note that the secondary electron emission efficiency η is
Irradiated electron beam (the amount (dose) of the irradiated electron beam is, for example,
It is stored in the RAM 134 and is known. Released against)
Defined by the percentage of secondary electrons Therefore, CPU1
31 corresponds to the outer shape of the pattern (material A or B)
Secondary electricity detected from the sensor 11
Digital image signal strength (brightness)
), The secondary electron emission efficiency η is determined by the amount of irradiated electron beam.
Can be calculated. in this way
The secondary electron emission efficiency η is a function of the amount of irradiated electron beam.
Calculated as the ratio of the secondary electrons emitted by the sensor 11
Can be

The contrast ρ of the whole image is
It is given by the ratio of the brightness intensity averaged for the lower pattern to the brightness intensity averaged for the upper pattern (the secondary electron emission efficiency η is within a small tolerance around 1). That is, the contrast ρ in the entire image is, for example, as shown in FIG.
Area and its surrounding area (neighboring area: lower pattern area)
(Material B) and the intensity (brightness) of the digital image signal having a correlation with the emitted secondary electrons detected from the sensor 11, the dark intensity (secondary) averaged over a plurality of pattern (material A) areas The electron emission efficiency η is given as a ratio of a bright intensity averaged over a plurality of peripheral regions (neighboring regions) to a small allowable value of around 1. Since the charge-up is affected by the scanning of the electron beam as shown in FIGS. 6B and 6C, it is necessary to calculate the contrast ρ in the entire image in consideration of this point. That is, the contrast ρ in the entire image is determined by comparing the plurality of upper pattern regions (material A) with respect to the dark intensity averaged for the peripheral region of the plurality of upper patterns (material A).
Is given as a ratio of the bright intensity (secondary electron emission efficiency η is within a small allowable value of about 1) averaged for the portion affected by the scanning inside. Obviously, the contrast ρ of a portion of the plurality of upper pattern regions (material A) which is not affected by scanning is clearly improved. Therefore, the CPU 131 determines whether the processing shown in FIG.
(B) As shown in (c), the intensity (brightness) of the digital image signal having a correlation with the secondary electrons emitted from the sensor 11 in the pattern (material A) region and its peripheral region (neighboring region) ), The contrast ρ of the entire image can be calculated.

Further, this concept is extended to the object 20.
If the term other than secondary electrons cannot be ignored if it is defined as a total sum of electron doses that do not accumulate in the object due to reflection, secondary electron emission transmission, leak, etc., on the electron beam irradiated on the These may be measured using a plurality of sensors and their values may be used. Further, as a method for setting the optimum inspection conditions, an electron beam is scanned at a low speed in the X direction while scanning in the Y direction by scanning the electron beam at a low speed in the Y direction while scanning the electron beam at a high speed in the X direction. The two-dimensional images are compared by scanning with each other, and the sum σ of the differences between the images over the entire image (the small sum σ means that the electron beam is scanned at high speed as shown in FIG. 6A) (Secondary electron emission efficiency η is almost close to 1).
6 means that charge-up occurs in the direction in which the electron beam is scanned at a high speed, as shown in FIGS. 6B and 6C. ) And the image contrast ρ between the upper pattern and the lower pattern (interval of the upper pattern) in one of the images can be calculated and stored as the image quality. Further, of the stored image qualities, the sum σ of image differences over the entire image is equal to or less than a certain allowable value (meaning that charge-up hardly occurs as shown in FIG. 6A), and furthermore, image contrast. Each of the potentials E ₀ , E ₁ , and E ₂ having the highest ρ can be stored as optimized test conditions.

As a method of setting the optimum inspection conditions,
The same location is scanned several times with an electron beam to detect an image and
These images are compared, and a sum σ of the difference between the images over the entire image (sum σ
Small means that the same location is scanned multiple times with an electron beam.
Charge-up hardly occurs (secondary electron emission
Output efficiency η is close to 1). )
Upper and lower patterns in one of the images
(Contrast between upper patterns)
Is calculated and stored as image quality. Internal image of stored image quality
Is less than a certain allowable value (charge
This means that almost no up occurs. ) And
Highest image contrast ρ or average over the entire image
As a condition that the change of the secondary electron emission efficiency η is the minimum, each potential E
₀, E₁, E _TwoCan be stored as optimal inspection conditions
You. In addition, the setting of the optimum inspection conditions is all performed automatically.
The calculation results of the information necessary to determine the inspection conditions
The image itself is presented to the worker, and the worker
Can achieve the same effect with the method that determines the optimal inspection conditions.
Wear. Also, image quality evaluation parameters and optimal inspection conditions
Is not limited to the above embodiment.
No. How to set inspection conditions based on information on the object
Will be described. In advance, as shown in FIG. 1 and FIG.
Acceleration voltage E on the object of material and potential gradient on the object
FIG. 15 shows the relationship between the secondary electron emission efficiency η and the distribution α.
External storage device 13 in the inspection condition optimization unit 27 shown in FIG.
7 or the RAM 134. At this time
As described in the embodiment, the object 20 is placed on the object 20.
Originating from the area of each specified repeated pattern
Waveforms that show physical changes such as secondary electrons and reflected electrons.
Or an image signal is detected by the sensor 11 and the A / D converter 2
4 and converted into a digital image signal and stored in the image memory 133.
The secondary electron emission from this stored digital image signal
In addition to calculating the output efficiency η, using a theoretical analysis method
Can also be calculated.

Next, the material located at the top of the cross-sectional structure made up of a plurality of materials constituting the object (inspection object) corresponding to the process number or the object number indicating the surface structure of the object 20 The input means 135 and the like are used to specify two materials, that is, the material of the upper pattern and the material located below (the material of the lower pattern), the film thickness and shape of the upper pattern, and the scanning conditions of the electron beam. The CPU 131 selects an inspection condition (for example, each potential E ₀ , E ₁ , E ₂ ) suitable for the specified surface structure of the target object 20 from the relation table stored in the external storage device 137 or the RAM 134, and selects the target object. The information is stored in the RAM 134 or the like in association with the process number or the object number indicating the surface structure of the object 20. The selection of the inspection conditions is such that, for example, the electron emission efficiency η from the upper material (upper pattern) is almost 1, and the secondary electron emission rate η from the lower material (lower pattern) is 0, for example. 0.7 to 1.2, and a condition where there is a certain difference with the secondary electron emission efficiency η from the material (upper pattern) located on the upper side. This is performed by obtaining the potentials E ₀ , E ₁ , and E ₂ . Naturally, in selecting inspection conditions, it is necessary to consider the thickness and shape of the upper pattern, the scanning conditions of the electron beam, and the like. This is because the charge-up characteristics particularly for the upper pattern change.

Next, setting of inspection conditions in the inspection condition setting section 28 will be described. The inspection conditions selected in advance by the inspection condition optimizing unit 27 are stored in the RAM 134 or the like. Accordingly, by inputting the process number or the object number indicating the surface structure of the object 20 in the inspection condition setting unit 28 using the input means 135 or the like, the R
Inspection conditions optimized from AM134 etc. (each potential E ₀ ,
E ₁ , E ₂ ) can be read and set for the potential control unit 23 via the overall control unit 26.

[0056] potential control unit 23, based on the set inspection conditions in the inspection condition setting unit 28 (the potentials E _0, E _1, E _2), the potential E ₀ with respect to the object 20, on the subject matter The potential E ₁ for the voltage applying means 19 and the potential E ₂ for the electron beam source 14 for applying the potential gradient α are controlled. (E ₀ −E ₂ ) is the object (sample) from the electron beam source 14.
It represents the potential difference up to 20, and is the acceleration voltage E shown in FIG. Further, (E ₀ -E ₁₎ is proportional to the potential gradient α on the object (sample) plane. FIG. 12 shows the potential gradient α
(In proportion to (E ₀ −E ₁ )) shows the secondary electron emission efficiency η when changing. When the potential gradient α is positive, that is, when the secondary electrons are decelerated, the secondary electrons are less likely to be emitted, so that the secondary electron emission efficiency η decreases. On the other hand, when the potential gradient α is negative, that is, when secondary electrons are accelerated, secondary electrons are easily emitted, and the secondary electron emission efficiency η increases. By controlling these two parameters in a predetermined relationship in the potential control unit 23, the secondary electron emission rate η is set to about 1 (within a small allowable value of about 1) for the material (upper pattern) located on the upper side. Charge-up can be suppressed as much as possible with respect to the upper pattern, and the image contrast ρ between the material located at the upper part (upper pattern) and the material not located at the upper part (lower pattern) can be optimized. This makes it possible to detect an image having sufficient contrast under conditions that do not cause charge-up of the upper pattern.

Further, according to these, it is possible to inspect minute defects and dimensions at high speed with high reliability in accordance with the sectional structure of the object. Pattern defects and dimensions can be inspected in the production line. In particular, by using an electron beam, it is possible to inspect defects and dimensions in a pattern such as an optically transparent oxide film or resist with high reliability.

Next, a second embodiment of the system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention will be described with reference to FIG. That is, the present system (inspection apparatus) includes an electron beam source 14 for generating an electron beam, a beam deflector 15 for scanning and imaging an electron beam, and an electron beam on a wafer 20 as an object. An objective lens (electrostatic optical system) 18 for forming an image,
A voltage applying means 19 such as a grid provided between the objective lens 18 and the wafer (object) 20, a wafer stage 20 on which the wafer 20 is mounted, and a sample stage 21 for holding the wafer 20 are scanned and positioned. Stage 46 and secondary electrons generated from the surface of the wafer 20 are detected by the secondary electron detector 16.
ExB (collected with an electric field E (electric field) and a magnetic field B (magnetic field)) 17 for collecting
A height detection sensor 13; a focus position controller 22 for adjusting the focus position of the objective lens 18 based on height information on the wafer surface obtained from the height detection sensor 13; , A sample stage potential adjustment 49 for adjusting the potential E ₀ of the sample stage 21, a grid potential adjustment 48 for controlling the potential E ₁ of the voltage applying means 19 such as a grid, and the electron beam source 14. Potential control unit 2 comprising a source potential adjustment 51 for controlling the voltage E ₂ of
1, an A / D converter 24 for A / D converting a signal from the secondary electron detector 16, an image memory 52 and an image comparing means 53, and A / D converted by the A / D converter 24. An image processing unit 25 that processes a digital image, an inspection condition optimization unit 27a that optimizes inspection conditions from an A / D converted digital image, and an inspection that is optimized and selected by the inspection condition optimization unit 27a. Inspection condition setting unit 28 for setting and storing conditions, and stage control unit 50 for controlling stage 46
And an overall control unit 26 for controlling the whole, the electron beam source 14, the beam deflector 15, and the objective lens (electrostatic optical system) 1.
8, a voltage applying means 19 such as a grid, and a vacuum sample chamber 45 containing a wafer 20 as an object (sample).

FIG. 14B shows the sequence of this system. In a method in which the inspection conditions are set in advance before the inspection, the cross-sectional structure of the surface changes depending on the type in which the cross-sectional structure of the surface changes in advance (the cross-sectional structure of the surface changes depending on each process. The sample (wafer) 20 is loaded onto the completed resist pattern, an insulating film pattern in which a through hole for connecting an upper wiring and a lower wiring between wiring layers is formed, or a wiring pattern. Step 31b) After the alignment (step 32b), the inspection condition optimizing unit 27
In step a, the inspection conditions are optimized (step 33).
b) Unloading (step 36b).

In the inspection condition optimizing process (step 33b) in the inspection condition optimizing unit 27a, a command is issued from the CPU 131 to the overall control unit 26, and each unit is initialized by the instruction from the overall control unit 26. The stage 46 is driven to move to a designated location, and the focal position of the objective lens 18 is set by the focal position control 22 so that the focus is adjusted to the height of the sample (wafer) 20 detected by the height detection sensor 13. The CPU 131 includes the external storage device 137 and the RAM 13
The display means 136 displays a predetermined menu stored at
, And the user specifies from this menu the one closest to the three-dimensional structure (cross-sectional structure) of the sample surface (particularly, the material of the upper pattern and the material of the lower pattern, etc.) by the input means 135 such as a mouse. The potential E ₂ of the electron beam source 14, the potential E ₁ of the voltage applying means 19 such as a grid, and the potential E ₀ of the sample table 21 registered in the menu are controlled by the potential control via the overall control 26. Source potential adjustment 51, grid potential adjustment 4 in section 23
8. Set the sample stage potential adjustment 48, and
And the focus position determined by the condition is set by the focus position control unit 22, and the electron beam from the electron beam source 14 is irradiated on the wafer 20 via the objective lens 18 by commanding via the overall control 26. Then, secondary electrons generated from the surface of the sample (wafer) 20 are collected by the ExB 17, an image is detected by the secondary electron detector 16, and converted into a digital image signal by the A / D converter 24. The CPU 131 temporarily stores the digital image signal obtained from the A / D converter 24 in the image memory 133 and displays the digital image signal on the display unit 136. In the displayed digital image, the CPU 131 has a repeatability and is located at the top. The user specifies the pattern using the input means 135 such as a mouse or the like, extracts the contour of the pattern, calculates the pattern shape information, and stores it in the RAM 134 or the external storage device 137. As described above, the pattern shape information including the repetition pitch is information determined by the inspection object, and thus may be obtained directly from the CAD data 138 and stored in the RAM 134 or the external storage device 137. Therefore, by designating the image detected by the secondary electron detector 16 based on the shape information of the pattern stored in the RAM 134 or the external storage device 137, the area from the upper pattern area or the lower pattern area is specified. The secondary electron emission rate η can be calculated.

Next, in accordance with a command from the CPU 131, the stage control unit 50 is controlled via the overall control unit 26 in order to make the region irradiated with the electron beam on the wafer a new surface region where no charge-up has occurred. While controlling the drive and scanning the stage 46 on which the sample stage 21 is installed, the potential controller 23 is controlled via the overall controller 26 to control each potential E.
₀ , E ₁ , and E ₂ are changed at a predetermined pitch, commanded via the overall control 26, a focus position offset determined by the conditions is set in the focus position control unit 22, and commanded via the overall control 26. The electron beam from the electron beam source 14 is
And the secondary electrons generated from the surface area of the repeated upper pattern and lower pattern on the wafer 20 in response to the change of the potentials E ₀ , E ₁ , and E ₂ are collected by the ExB 17. An image is detected by the secondary electron detector 16 and converted into a digital image signal by the A / D converter 24. The CPU 131 stores a digital image from the surface area of the upper pattern and the lower pattern that are repeated on the wafer 20 in accordance with a change in each of the potentials E ₀ , E ₁ , and E ₂ obtained by the A / D converter 24 in the image memory 133. Remember,
In the digital image corresponding to the change of the stored potentials E ₀ , E ₁ , E ₂ , the RAM 134 or the external storage device 1
By designating the upper pattern area or the lower pattern area based on the pattern shape information stored in 37, the upper pattern area and the lower pattern area according to the change of each of the potentials E ₀ , E ₁ , and E ₂ . The secondary electron emission rate η in the region and the contrast ρ in the entire image (expressed as the difference between the secondary electron emission ratio η in the upper pattern region and the secondary electron emission ratio η in the lower pattern region) Is calculated and stored in the external storage device 137 or the like. CP
As shown in FIGS. 11 and 12, U131 is a small (approximately 1) allowable value in which the secondary electron emission rate η from the upper pattern is about 1 in the image quality stored in the external storage device 137 or the like. Within (with little charge-up to the upper pattern) and within a large allowable value of the secondary electron emission rate η from the lower pattern of about 1 (to minimize charge-up to the lower pattern). And potentials E ₀ , E ₁ , E _{2 at which an} appropriate image contrast ρ is obtained.
Is obtained and stored in the external storage device 137 or the like as the inspection conditions (each potential E ₀ , E ₁ , E ₂ ) corresponding to the type of the cross-sectional structure of the surface of the inspection object (including each process). At the time of image detection, the focus position control unit 22 controls to follow the focus position obtained by adding the focus position offset to the output of the height detection sensor 13. CPU1
31 is, for example, the image comparison means 5 in the image processing unit 25.
The secondary electron emission rate η from the upper pattern is set based on the actually inspected defect information (especially erroneous detection information) obtained from Step 3 or the inspection criterion (defect criterion) in the image comparing means 53. By calibrating (adjusting) a small allowable value around 1 or a large allowable value set around the secondary electron emission rate η from the lower pattern η, the inspection conditions (each potential E ₀ , E ₁ , E
₂ ) is corrected, and the inspection condition (each potential E ₀ , E ₁ , E ₂ ) is set again in the inspection condition setting section 28, so that erroneous detection can be prevented in the actual inspection in the image processing section 25. The allowable value for the secondary electron emission rate η is determined by the inspection determination criterion (defect determination criterion) in the image comparing means 53.
It is because it is related. Of course, the CPU 131 uses the history of the defect information (especially erroneous detection information) actually inspected obtained from, for example, the image comparing unit 53 in the image processing unit 25 based on the history associated with the surface cross-sectional structure of the inspection object. It is also possible to directly calibrate the inspection conditions (each potential E ₀ , E ₁ , E ₂ ). CPU 131
When calculating the secondary electron emission rate η from the upper pattern or setting a small allowable value of about 1 to the secondary electron emission rate η, the shape of the upper pattern obtained from the CAD data 138 ( By making adjustments based on information such as line width and spacing) and thickness, more appropriate inspection conditions can be selected.

Next, an inspection process for the inspection object (wafer) 20 to be actually inspected will be described. First, before loading the inspection object (wafer) 20 to be actually inspected, the inspection condition setting unit 28 determines the type (including each process) in which the cross-sectional structure of the surface of the inspection object to be actually inspected changes. By inputting using the input unit 135 or the like, the inspection conditions (each potential E) corresponding to the inspection object actually inspected and stored in the external storage device 137 or the like.
₀ , E ₁ and E ₂ ) are selected and set and stored in the RAM 134 or the like. Next, based on a command from the overall control unit 26, the inspection object (wafer) 20 to be actually inspected is loaded (step 31c) and aligned (step 32).
c) Thereafter, according to the inspection conditions (each potential E ₀ , E ₁ , E ₂ ) corresponding to the type of the inspection object (wafer type and process) previously set and stored in the RAM 134 or the like of the inspection condition setting unit 28. By controlling the source potential adjustment 51, the grid potential adjustment 48, and the sample stage potential adjustment 48 constituting the potential control unit 23, each of the potentials E ₀ , E ₁ , and E ₂ is obtained (step 34).
c), the focus position offset determined by the condition is set by the focus position control unit 22. After the setting, based on the command of the overall control unit 26, the stage 46 is driven and driven in the Y direction at a constant speed under the control of the stage control unit 50, and the electron beam is controlled by the beam deflector 15 under the control of the scan control unit 47. The electron beam from the source 14 is scanned in the X direction, secondary electrons obtained from the surface of the inspection object 20 are collected by the secondary electron detector 16 by the ExB 17, and are successively two-dimensionally detected by the secondary electron detector 16. A / D converter 2 detects the secondary electron image of
At 4, the image signal is converted into a two-dimensional digital secondary electronic image signal and stored in the image memory 52 of the image processing unit 25.
Of the detected two-dimensional digital secondary electronic image signal and the two-dimensional digital secondary electronic image signal stored in the image memory 52, for example, an image comparison between image signals for each chip, which is expected to have the same pattern, is performed. The means 53 compares and detects different parts as defects, and stores information on the defects including the position coordinates of the defects in the image processing unit 25 or in the memory of the overall control unit 26 (step 35c). When the inspection is completed at all places to be inspected, the inspection object 20
Is unloaded from the sample table 21 (step 36).
c).

Next, a description will be given of a modified example different from the above-described inspection condition optimizing process in the inspection condition optimizing section 27a. That is, a first modified example of the present embodiment is as follows.
Instead of calculating the secondary electron emission rate η at a location specified and registered in the dictionary in advance, the CPU 131 calculates an average secondary electron emission rate η in a specified range registered in the dictionary. That is, the CPU 131 preliminarily stores an external storage device (dictionary) from the secondary electron emission rates η in the upper pattern area and the lower pattern area in accordance with the change of each of the potentials E ₀ , E ₁ , and E _2.
The average secondary electron emission rate η is calculated for a range registered in 137 or the like (a range in which a plurality of repeated upper pattern regions and lower pattern regions are repeated). Then, the CPU 131 selects an inspection condition (each potential E ₀ , E ₁ , E ₂ ) in which the calculated average secondary electron emission rate η falls within a small allowable value of about 1 (a value close to ₁ ). I do.
As a result, although the contrast ρ slightly decreases, charge-up does not occur on the surface of the inspection object on average, so that stable inspection can be performed for a long time.

A second modification of the present embodiment is a
In addition to the calculation of the secondary electron emission rate η at the place specified and registered in the dictionary in advance by the PU 131, the PU 131 calculates the average secondary electron emission rate η in the specified range registered in the dictionary in advance. Select inspection conditions close to. That is, the CPU 131
Calculates the secondary electron emission rate η from the area of the upper pattern in accordance with the change of each of the potentials E ₀ , E ₁ , and E _{2 and} the average secondary electron emission rate η over the above-mentioned range, and weights these. Average 1
(Each potential E ₀ , E ₁ , E ₂ ) is selected.
As a result, the charge-up of the upper pattern and the average charge-up can be optimized, and a long detective inspection can be performed.

A third modification of the present embodiment is a modification of C
Instead of calculating the secondary electron emission rate η at the place designated by the PU 131 registered in the dictionary in advance, the PU 131 calculates the secondary electron emission rate η at the place designated by the worker. That is, in accordance with a command from the CPU 131, the stage control section 5 is controlled via the overall control section 26 in order to make the area irradiated with the electron beam on the wafer a new surface area in which no charge-up has occurred.
0 while scanning the stage 46 on which the sample stage 21 is installed by controlling the driving of the potential controller 23 via the overall controller 26.
To change the potentials E ₀ , E ₁ , and E ₂ at a predetermined pitch, set a focal position offset determined by the conditions in the focal position control unit 22 by instructing via the overall control 26,
An electron beam from the electron beam source 14 is directed to the wafer 20 via the objective lens 18 under the command of the overall control 26, and the electron beam is repeatedly applied to the wafer 20 according to the change of each of the potentials E ₀ , E ₁ , and E _2. The secondary electrons generated from the surface regions of the upper pattern and the lower pattern to be collected are collected by the ExB 17, an image is detected by the secondary electron detector 16, and is converted into a digital image signal by the A / D converter 24. Digital images from the surface area of the upper pattern and the lower pattern that are repeated on the wafer 20 in accordance with the changes of the potentials E ₀ , E ₁ , and E ₂ obtained by the / D converter 24 are stored in the image memory 133. A digital image corresponding to the change of each potential E ₀ , E ₁ , E ₂ is displayed on the screen of the display means 136,
By using the input means 135 or the like to specify the location (region) where the secondary electron emission rate η is calculated for the digital image corresponding to the change of the displayed potentials E ₀ , E ₁ , and E ₂ , It is possible to calculate the secondary electron emission rate η and the contrast ρ at the designated portion (region). This eliminates the need for dictionary registration and allows selection of inspection conditions even for patterns that are not necessarily repeatable. Further, while clipping each potential E ₀ , E ₁ , E ₂ using the input means 135 or the like, a digital image corresponding to the change of each potential E ₀ , E ₁ , E ₂ displayed on the screen of the display means 136 is displayed. While observing, no charge-up was observed directly on the upper pattern without calculating the secondary electron emission rate η and contrast ρ,
In addition, inspection conditions (each potential E ₀ , E ₁ , E ₂ ) having an appropriate contrast ρ are selected and stored in the external storage device 137 or the like in accordance with the type of the inspection object (the cross-sectional structure of the surface). Can be. When the CPU 131 calculates the secondary electron emission rate η and the contrast ρ to optimize the inspection conditions (each potential E ₀ , E ₁ , E ₂ ), the optimized digital image is displayed on the display means 136. Display on the screen, it is possible to confirm that the inspection conditions are appropriate.

A fourth modification of the present embodiment is a modification of C
Instead of calculating the secondary electron emission rate η at a place designated by the PU 131 registered in the dictionary in advance, the PU 131 calculates an average secondary electron emission rate η within the entire image or within a range designated by the operator. As a result, there is no need to register a dictionary, and even if the pattern is not necessarily repeatable, the inspection conditions (each potential E ₀ , E ₁ ,
E ₂ ) can be selected and charge-up does not occur on average, so that a long-term stable inspection can be realized. In a fifth modification of the present embodiment, instead of the CPU 131 calculating the secondary electron emission rate η at a location designated and registered in a dictionary in advance, a plurality of scanning methods (FIGS. 6B and 6C) are used. By changing the scanning direction as shown in the figure or scanning the same portion continuously for a plurality of times) to detect digital images by secondary electrons and the like (the degree to which there is no difference between the digital images).
Is calculated, and the inspection condition (the potentials E ₀ ,
E ₁ , E ₂ ) are selected. In other words, when charge-up occurs on the surface of the object to be inspected, the charge-up phenomenon is changed by scanning a plurality of electron beams in a relatively short time, even if the charge-up relaxation phenomenon occurs. Should occur. Therefore, when no change is observed between the detected digital images (the degree of coincidence is high), it indicates that no charge-up has occurred on the surface of the inspection object. For the contrast ρ,
It can be calculated from a digital image that can be detected. According to this, inspection conditions can be selected without specifying a registered dictionary or an operator. It should be noted that a phenomenon (charging up) on the surface of the object to be inspected can be grasped by the difference (change) between the detected digital images.

A sixth modification of the present embodiment is a modification of C
Instead of calculating the secondary electron emission rate η at the location designated and registered in the dictionary by the PU 131 in advance, the dictionary stores a pattern that can be detected as the same digital image signal even when the scanning direction is changed by 180 degrees on the inspection object. By registering and designating the position of the pattern, the electron beam 172 irradiated with the pattern 171 is aligned through the overall control unit 26 as shown in FIG.
The electron beam 172 is reciprocally scanned by 173 and 174 by changing the scanning direction of the electron beam by 180 degrees with respect to 71, and the digital image signal obtained from one of the scanning lines is mirror-inverted by 180 degrees and this inverted digital image is inverted. The signal is compared with a digital image signal obtained from the other scanning line to calculate the degree of coincidence. The degree of coincidence is high, and the contrast ρ calculated based on the detected digital image is appropriate for the inspection condition ( each potential _{E 0, E 1, E 2} ) to select a. When charge-up occurs in the pattern 171, a digital image appears in each of the reciprocating scanning lines 173 and 174, with a tail 175 drawn downstream of the scanning line in the pattern 171. Therefore, by comparing a digital image signal obtained by inverting a digital image signal obtained from one scanning line by 180 degrees with a digital image signal obtained from the other scanning line, the pattern 17 is obtained.
When charge-up occurs in pattern 1, pattern 171
Tail 175 will appear as a mismatch (difference) on both sides of. When no charge-up occurs in the pattern 171, the tail 175 is not generated as a digital image downstream of the scanning line in the pattern 171 in each of the reciprocating scanning lines 173 and 174, and the matching degree is high. That is, it is possible to select an inspection condition (each potential E ₀ , E ₁ , E ₂ ) that does not cause charge-up in the pattern 171. According to this modification, it is possible to select an appropriate inspection condition without information on the cross-sectional structure of the inspection object. The pattern 1 is obtained by comparing a digital image signal obtained by inverting a digital image signal obtained from one scanning line by 180 degrees with a digital image signal obtained from the other scanning line.
Tail 17 appearing as a mismatch (difference) on both sides of 71
By detecting No. 5, the charge-up phenomenon occurring in the pattern 171 can be grasped.

A seventh modification of the present embodiment is a modification of C
Instead of the PU 131 calculating the secondary electron emission rate η at a location designated by registering it in a dictionary in advance, as shown in FIG. An image is detected and, for example, the first detected digital image is compared with a plurality of detected digital images to calculate the degree of coincidence, and the degree of coincidence is high, and the contrast calculated based on the detected digital image ρ selects an appropriate inspection condition (each potential E ₀ , E ₁ , E ₂ ). That is, if charge-up occurs in the upper pattern, for example, the difference between the first detected digital image and the plurality of detected digital images increases. Conversely, if no charge-up has occurred in the upper pattern, for example, 1
There is almost no difference between the first and second detection digital images, and the degree of coincidence is high. Therefore, it is possible to select an inspection condition (each potential E ₀ , E ₁ , E ₂ ) that does not cause charge-up in the upper pattern. Conversely, according to this modified example of comparison, an appropriate inspection condition can be selected without information on the surface sectional structure of the inspection object.

In an eighth modification of the present embodiment, instead of automatically selecting the inspection conditions, the CPU 131 sets the secondary electron emission rate η at the specified location, and the degree of coincidence of digital images detected by a plurality of scanning methods. Then, the image quality evaluation parameters such as the contrast of the digital image are displayed on the display means 136 and presented to the operator to select the inspection conditions. According to this modification, it is possible to select appropriate inspection conditions with a simple configuration. In a ninth modification of the present embodiment, instead of automatically selecting the inspection condition, the CPU 131 displays the digital image detected in correspondence with each of the potentials E ₀ , E ₁ , and E ₂ to be changed. It is presented to the operator by displaying it at 136 or the like, and the appropriate inspection conditions (the potentials E ₀ , E ₁ , E ₂ ) are selected based on the observed digital image. According to this modification, without information on the surface cross-sectional structure of the inspection object,
Moreover, the inspection conditions can be selected with a simple configuration. Also, it is clear that appropriate inspection conditions (each potential E ₀ , E ₁ , E ₂ ) may be selected by applying a plurality of modified examples described above.

As described above, according to this embodiment, wafers (objects to be inspected) of various types and processes can be inspected under appropriate inspection conditions (each potential E ₀ , E ₁ , E ₂ ). Inspection of defects and dimensions of patterns on a wafer (object to be inspected) having various surface cross-sectional structures in a plurality of processes as well as a specific product type can be realized. As a result, as shown in FIG. 21, it can be used as a visual inspection apparatus, and inspects fine defects and dimensions in a resist pattern or an insulating film pattern having a surface cross-sectional structure that cannot be optically inspected in the course of a manufacturing process. Can be realized inline. Of course, it can also be implemented offline.

Next, a semiconductor wafer is formed using the electron beam according to the present invention.
A system for detecting patterns on an object such as eha
The third embodiment will be described with reference to FIG. Immediately
The system (device) is an electron beam generating electron beam.
Source 14 and a beam for scanning and imaging the beam
A deflector 15 and a wafer 20 which is an electron beam to be inspected.
The objective lens 18 to be imaged on the
Voltage applying means 19 such as a grid provided between EHAs 20
And a sample stage 21 for holding a wafer 20
A stage 46 for scanning and positioning the 20;
A secondary electron detector 1 detects secondary electrons generated from the surface of the wafer.
ExB to collect in 6 (electric field E (electricfield)
To which a magnetic field B (magnetic field) is applied) 17
And the height detection sensor 13 and the height detection sensor 13
Objective lens 18 based on height information of the wafer surface
A focus position control unit 22 for adjusting the focal position of the
Scanning system that realizes electron beam scanning by controlling the director 15
Control unit 47 and the potential E of the sample stage 21 ₀Adjust the sample stage power
Potential adjustment 49, potential E of voltage applying means 19 such as a grid.₁
Potential adjustment 48 and electron beam source 14
Voltage E_TwoPotential control consisting of source potential adjustment 51 for controlling
A / D conversion of signals from the section 21 and the secondary electron detector 16
A / D converter 24, image memory 52 and image ratio
The A / D converter 24 performs A / D conversion.
An image processing unit 25 for processing the digital images
Based on the surface cross-sectional structure of the inspected object obtained from
An inspection condition optimizing unit 27b for optimizing the inspection conditions by
Inspection optimized and selected by the inspection condition optimization section 27b
An inspection condition setting unit 28 for setting and storing conditions;
6 and a stage control unit 50 for controlling
Controller 26, the electron beam source 14, the beam deflector 1
5. Voltage of objective lens (electrostatic optical system) 18, grid, etc.
Application means 19 and wafer 20 as an object (sample)
And the like, and a vacuum sample chamber 45 containing therein. Different from FIG.
This is the inspection condition optimization unit 27b.

FIG. 14C shows the sequence of this system. In this method, inspection conditions are set based on a plurality of materials constituting the inspection object 20. The optimization of the inspection conditions in the inspection condition optimization unit 27b is performed as described below. That is, as shown in FIG. 1 and FIG. 10, the CPU 131 sets the acceleration voltage E on the sample, the potential gradient α on the sample, and the The relationship with the release efficiency η is theoretically calculated based on the experimental value input using the input means 135 and stored in the external storage device 137 or the like. Next, a plurality of materials (a material located at the upper portion and a material located at the lower portion) constituting the cross-sectional structure of the surface according to the type of the object to be inspected are designated using the input means 135 or the like. The CPU 131 determines that the secondary electron emission efficiency η of the specified upper material is within a small allowable value of about 1 (approximately 1), and the secondary electron emission rate η of the lower material is, for example, 0. 7 to 1.
The difference from the secondary electron emission efficiency η of the material located above and within a predetermined allowable range such as 2 (contrast ρ)
Searches for appropriate inspection conditions (each potential E ₀ , E ₁ , E ₂ ) and stores them as appropriate inspection conditions in the external storage device 137 or the like (step 37d). Naturally, the external storage device 137 and the like store a group of appropriate inspection conditions corresponding to each type over the number of types of the inspection target.

Next, the actual inspection of the wafer will be described. First, before actually inspecting a wafer, the inspection condition setting unit 28 selects a wafer to be inspected from a group of inspection conditions (each potential E ₀ , E ₁ , E ₂ ) stored in the external storage device 137 or the like. Type (consisting of product type and process)
Is selected and stored in the RAM 134 or the like. Next, in response to a command from the overall control unit 26, the wafer to be actually inspected is loaded (step 31d) and aligned (step 32d), and then the inspection conditions stored in the inspection condition setting unit 28 are read out to control the potential. Each of the potentials E ₀ , E ₁ , and E ₂ is controlled by a sample stage potential adjustment 49, a grid potential adjustment 48, and a source potential adjustment 51 included in the unit 23, and the focus position offset determined by these conditions is used as the focus position control unit. 22 is set (step 34d). After this setting, the stage 4 is controlled by a command from the overall control unit 26.
The scanning controller 4 is driven in the Y direction at a predetermined speed under the control of the stage controller 50 (the scanning in the Y direction may be performed by scanning with the beam deflector 15).
7, the electron beam from the electron beam source 14 is scanned in the X direction using the beam deflector 15 to detect a continuous two-dimensional image signal from the secondary electron detector 16, and the A / D converter 24 And converts it into a two-dimensional digital image signal and stores it in the image memory 52 of the image processing unit 25. Next, in the image comparing means 53, it is expected that the detected two-dimensional digital image signal and the two-dimensional digital image signal stored in the image memory 52 are originally the same (for example, a repeated chip or block or unit area). Image signals (for each pattern) are compared, and different portions are determined as defects based on an inspection criterion (determination criterion), and are recorded in a memory in the image processing unit 25 or the overall control unit 26. (Step 35d). When the inspection is completed for all the places to be inspected for the wafer 20, the wafer 20 is unloaded (step 36d).

The first modification according to the present embodiment is different from the first embodiment in that the search conditions (each potential E ₀ , E ₁ , E ₂ ) obtained by searching only based on the information of the object to be inspected are used instead of the search. (Each potential E ₀ , E ₁ ,
Calibration in the vicinity of E ₂ ) by the method described in the second embodiment (optimization of inspection conditions based on a digital image signal obtained by detecting secondary electrons generated from the surface of the inspection object). By doing so, it is possible to calculate inspection conditions suitable for the cross-sectional structure of the actual wafer surface. That is, the phenomenon of charge-up is not determined only by the material of the pattern in the cross-sectional structure of the surface,
This is because it changes depending on the shape and thickness of the upper pattern. According to the present modification, it is possible to set accurate inspection conditions in the shortest time.

In this embodiment, the same operation and effect as those of the second embodiment can be obtained. That is, wafers of various types and processes can be inspected under optimal inspection conditions, and the present invention can be applied to wafers obtained in a plurality of processes as well as specific types.

Next, a fourth embodiment of a system for detecting (observing) a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention will be described with reference to FIG. FIG. 19 is a schematic configuration diagram showing an embodiment of the observation SEM according to the present invention. The system (apparatus) includes an electron beam source 14 for generating an electron beam, a beam deflector 15 for scanning and imaging a beam, and an objective lens 18 for forming an image of the electron beam on an object 20. Voltage applying means 19 such as a grid provided between the objective lens and the object
And a stage 46 on which the sample stage 21 for holding the object 20 is set and the object 20 is scanned and positioned.
And ExB (electric field E) for collecting secondary electrons generated from the surface of the object to the secondary electron detector 16.
ld) and a magnetic field B (magnetic field)
17, a height detection sensor 13, a focus position control unit 22 for adjusting the focus position of the objective lens 18 based on height information on the surface of the object obtained from the height detection sensor 13, and a beam deflector 15. A scanning controller 47 for controlling the electron beam scanning, a sample stage potential adjustment 49 for adjusting the potential E ₀ of the sample stage 21, and a grid potential adjustment 48 for controlling the potential E ₁ of the voltage applying means 19 such as a grid. And a potential control unit 21 comprising a source potential adjustment 51 for controlling the voltage E ₂ of the electron beam source 14, and a signal from the secondary electron detector 16 to A /
A / D converter 24 for D / D conversion and A / D converter 24
An image display unit 54 for displaying the / D converted digital image on a monitor 55 such as a display, and an inspection condition optimizing unit for optimizing the inspection conditions based on the surface cross-sectional structure of the object to be inspected obtained from design information and the like. 27b, an inspection condition setting unit 28 for setting and storing inspection conditions optimized and selected by the inspection condition optimization unit 27b, a stage control unit 50 for controlling the stage 46, and an overall control unit for controlling all of them. 26, voltage applying means 19 such as an electron beam source 14, a beam deflector 15, an objective lens (electrostatic optical system) 18, and a grid.
And a vacuum sample chamber 45 containing the wafer 20 or the like as an object (sample). 16 and 18 is that an image display unit 54 and a monitor 55 are provided instead of the image processing unit 25. Since the inspection condition optimizing unit 27b has the function of the image display unit 54 and also includes the monitor (display unit) 136, the monitor 5
A monitor (display means) 136 can be used in place of 5.

The sequence of this system is shown in FIG.
As shown in the figure, it is the same as in the third embodiment. However,
In the inspection in step 35d, the stage 46 is driven in the Y direction at a predetermined speed under the control of the stage control unit 50 in accordance with a command from the overall control unit 26 in accordance with an instruction from the operator (the scanning in the Y direction is performed by beam deflection). Table 15
May be used in combination. ), The secondary electron detector 16 scans the electron beam from the electron beam source 14 in the X direction using the beam deflector 15 under the control of the scanning controller 47.
, A continuous two-dimensional image signal is detected from the A / D converter 2
The image is converted into a two-dimensional digital image signal by the image display unit 54 in
And stored in an image memory provided therein. Then, the image display section 54 cuts out the designated image from the image signals stored in the image memory, enlarges the image on the monitor 55, and presents it to the operator. Therefore, the operator can enlarge and observe a specific partial image on the surface of the object. According to the present embodiment, observation can always be performed under conditions that do not cause charge-up, regardless of changes in the material of the surface of the object.

Next, a semiconductor wafer is formed using the electron beam according to the present invention.
A system for detecting patterns on an object such as eha
The fifth embodiment will be described with reference to FIG. FIG.
0 is the length measuring device for inspecting the dimension of the pattern according to the present invention.
It is a schematic structure figure showing one embodiment. This system (package
) Includes an electron beam source 14 for generating an electron beam and a beam.
A beam deflector 15 for scanning and imaging;
An objective lens 18 for imaging a line on an object 20;
With voltage such as a grid provided between the object lens and the object
And a sample stage 21 for holding the object 20.
To scan and position the object 20
Stage 46 and secondary electrons generated from the surface of the object.
ExB (electric field E (el
ectric field) and magnetic field B (magnetic field)
17), the height detection sensor 13, and the height detection sensor.
Based on height information of the surface of the object obtained from the sensor 13
Position controller for adjusting the focal position of the objective lens 18
22 and scanning of the electron beam by controlling the beam deflector 15
And a potential E of the sample table 21. ₀To
Sample stage potential adjustment 49 to be adjusted, voltage applying means such as grid
The potential E of the stage 19₁Grid potential adjustment 48 and
And the voltage E of the electron beam source 14_TwoSource potential adjustment 51 for controlling
And a potential control unit 21 composed of
A / D converter 24 for A / D converting a signal, and A / D conversion
For storing a digital image that has been A / D converted by the imager 24
A digital image stored in the image memory.
Measurement processing for measuring the dimensions of a given pattern based on an image
The image processing unit 25 having the unit 56 and the A / D converter 24
The surface of the inspected object based on the digital image obtained
Inspection conditions suitable to optimize inspection conditions according to the cross-sectional structure
The inspection condition optimization unit 27a and the inspection condition optimization unit 27a
Inspection condition setting unit that sets and stores the inspection condition selected
28 and a stage controller 50 for controlling the stage 46
And an overall control unit 26 for controlling the whole thereof, and an electron beam source
14, beam deflector 15, objective lens (electrostatic optical system) 1
8, a voltage applying means 19 such as a grid and an object (test
Vacuum chamber 45 containing the wafer 20 and the like
It becomes. The difference from FIG. 16 and FIG.
Measure the dimensions of the pattern on the inspection object in 25
Is to do. Note that the image processing unit 25
In order to measure the dimensions of the
And the amount of electron beam deflection (scanning) applied to the beam deflector 15.
And the stage is controlled by the stage controller 50.
Data on the amount of displacement (travel) is required. Therefore,
The image processing unit 25 has a beam deflector 1 from the scanning control unit 47.
Deflection amount (scanning amount) and stay of electron beam given to 5
The amount of displacement (running) for moving the stage by the
(Line amount) data (position information) 221 is input.

The sequence of this system is shown in FIG.
As shown in the figure, it is the same as the second embodiment. However,
In step 35c, the electron beam source 14 is driven by the beam deflector 15 under the control of the scanning control unit 47 while the stage 46 is driven in the Y direction at a predetermined speed under the control of the stage control unit 50 under the command of the overall control unit 26. The electron beam is scanned in the X direction to detect a continuous two-dimensional image signal from the secondary electron detector 16, is converted into a two-dimensional digital image signal by the A / D converter 24, and is sent to the image processing unit 25. It is stored in the provided image memory. The image processing unit 25 includes a deflection amount (scanning amount) of the electron beam input from the scanning control unit 47 to the beam deflector 15 and a stage control unit 50.
Based on the image data stored in the image memory, the dimensions of a desired pattern formed on the surface of the object are measured using displacement (travel distance) data (position information) 221 that causes the stage to travel. Then, the result is stored in a memory in the image processing unit 25 or the overall control unit 26, and output to be presented to an operator as needed.

According to the present embodiment, it is possible to measure patterns on a wafer in various qualities and processes under appropriate inspection conditions, and to measure not only a specific product type but also dimensions of a pattern on a wafer obtained from a plurality of processes. Accurate measurement, and as a result,
It can be used as the quality inspection device shown in FIG. That is, it is possible to accurately measure a fine line width or the like of a resist pattern or a pattern of an insulating film or the like that cannot be optically measured during the manufacturing process, and as a result, a quality inspection can be realized. Next, sixth to tenth embodiments of a system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention will be described with reference to FIGS. FIG. 22 is a diagram showing a sixth embodiment of a system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention. In the sixth embodiment, when a charge-up occurs on the surface of the inspection object 20, the sensor 11 (16) is detected by the sensor 11 (16) as shown in FIGS. 4 to 6, 8, and 17. In the image processing unit 25, an inspection criterion (judgment criterion) is applied to a charge-up phenomenon that appears in a digital image signal obtained by converting an image signal due to, for example, secondary electrons, which represents the physical properties of the inspection object, by the A / D converter 24. ) To reduce the influence of this charge-up so that correct inspection can be performed.

That is, in the embodiment shown in FIG. 22, the inspection condition optimizing section 27a
Is a sensor 1 for each type having different surface cross-sectional structures of the object to be inspected, according to the scanning direction in which the electron beam scans at high speed.
1) High-speed scanning of an electron beam based on a digital image signal of, for example, secondary electrons which indicates the physical properties of the inspection object detected by the A / D converter 24 and detected by the A / D converter 24. In accordance with the direction, for example, as shown in FIG. 6B or FIG. 6C and FIG. 8B, a change area (change area due to charge-up) of the digital image signal due to charge-up is extracted. If necessary, a charge-up determination such as obtaining an average brightness in the change area is performed, and the result is stored in the external storage device 137 or the like for each type of the inspection object. Extraction of a change region of the digital image signal due to occurrence of charge-up can be realized by using, for example, two thresholds for erasing the brightness of the upper pattern region and erasing the brightness of the lower pattern region. This is because the brightness of the change area due to the charge-up is intermediate between the brightness of the upper pattern area and the brightness of the lower pattern area. Therefore, in the inspection condition optimizing unit 27a, the external storage device 1
37, etc., two-dimensional mask data indicating a changed area due to repeated charge-up of, for example, a chip or a block or a unit area, corresponding to a scanning direction in which an electron beam is scanned at a high speed for each type of the inspection object. (Mask signal) (for example, shown in FIGS. 6D and 6E and FIG. 8C) is formed. However, a process for enlarging only the change area is performed on two-dimensional mask data (mask signal) indicating a change area due to charge-up, and the result is stored as mask data (mask signal) 222 in the external storage device 137 or the like. It is desirable to keep. In addition, in a repeated chip, block or unit area on the same type of object to be inspected, for example, a plurality of types of charge-up phenomena may have different surface cross-sectional structures, so two-dimensional mask data is prepared accordingly. There is a need.

The inspection criterion (judgment criterion) in the change area due to charge-up may be determined based on the average brightness in the change area obtained by the CPU 131. In addition, the inspection criterion (judgment criterion) other than the above-mentioned change area may be determined based on the image contrast ρ between the upper pattern area and the lower pattern area.

Next, the actual inspection of the inspection object (wafer) will be described. First, the inspection condition setting unit 28
Reads the mask signal corresponding to the type of the inspection target specified at the time of the actual inspection from the external storage device 137 or the like, and sets and stores the mask signal in the RAM 134 or the like. Next, the electron beam source 14 is driven by the beam deflector 15 under the control of the scanning control unit 47 while the stage 46 is driven in the Y direction at a predetermined speed under the control of the stage control unit 50 according to the command from the overall control unit 26. The electron beam is scanned in the X direction to detect a continuous two-dimensional image signal from the sensor 11 (secondary electron detector 16), and is converted into a two-dimensional digital image signal by the A / D converter 24 to perform image processing. It is stored in the image memory 52 of the unit 25. Next, in the image comparing means 53, it is expected that the detected two-dimensional digital image signal and the two-dimensional digital image signal stored in the image memory 52 are originally the same (for example, a repeated chip or block or unit area). When comparing image signals (for each), the RAM 1
The mask data 222 stored in the storage device 34 or the like is read, and the deflection amount (scanning amount) of the electron beam given to the beam deflector 15 from the scanning control unit 47 and the displacement amount (traveling amount) for moving the stage by the stage control unit 50 are read. Based on the data (position information) 221, the read mask data 22
2 is aligned with the two-dimensional digital image signal to be compared, the inspection criterion (judgment criterion) is changed between the changed area and the other area based on the mask data 222, and a portion where the image signals are different is regarded as a defect. It is determined and recorded in the memory in the image processing unit 25 or the overall control unit 26. That is, when the image comparing means 53 compares image signals that are originally expected to be the same (for example, for each repeated chip, block, or unit area), a change area due to charge-up based on the mask data 222 is used. By changing the inspection criterion (judgment criterion) between and the other area (for example, reducing the sensitivity in a change area due to charge-up), even if a change occurs in the digital image signal detected by the charge-up, erroneous detection is performed. Can be prevented.

By the way, as shown in FIGS. 6 and 17, the change area due to charge-up changes mainly in relation to the scanning direction in which the electron beam is scanned at a high speed. By rotating the object to be inspected 20 by 90 or 180 degrees by rotating it, the scanning direction of the electron beam is changed, and a continuous two-dimensional image signal is detected again from the sensor 11 (secondary electron detector 16). By converting into a two-dimensional digital image signal by the / D converter 24 and inspecting by the image processing unit 25, it is possible to inspect over the entire area with the same inspection criterion (judgment criterion).

FIG. 23 is a view showing a seventh embodiment of a system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention. In the seventh embodiment shown in FIG. 23, the inspection object 20 (2
8), and after the stage 46 is positioned under the control of the stage control unit 50 in accordance with a command from the overall control unit 26, a certain chip or block or a unit area (in the case of a pattern ), The electron beam is scanned once and the sensor 11 is scanned.
A continuous first two-dimensional image signal is detected from the (secondary electron detector 16), converted to a first two-dimensional digital image signal by the A / D converter 24, and converted into an image memory of the inspection condition optimizing unit 27c. 232 and the image memory 52 of the image processing unit 25. Next, for the same chip or block or unit area (including the case of a pattern),
The electron beam is scanned a plurality of times (the direction of high-speed scanning may be changed). A continuous two-dimensional image signal is detected from the sensor 11 (secondary electron detector 16), and the A / D converter is used. 24
Is converted into a second two-dimensional digital image signal, and the charge-up determination unit 233 including the CPU and the like of the inspection condition optimization unit 27c is used to convert the image memory 232 (13
The difference between the first two-dimensional digital image signal stored in 3) and the second two-dimensional digital image signal is calculated, and two-dimensional mask data (mask signal) indicating a change area due to charge-up (for example, FIG. 6 (d) (e) and FIG.
(Shown in (c)) is formed and stored in the memory 234. However, a process for enlarging only the change area is performed on the two-dimensional mask data (mask signal) indicating the change area due to the charge-up, and the result is converted into mask data (mask signal) 2.
It is desirable to store it as 35 in the memory 234. In addition, as for the inspection criterion (judgment criterion) in the change area due to the charge-up, the charge-up judging unit 2
33 may be determined based on the average brightness in the above-mentioned change area. As for the inspection criterion (judgment criterion) other than the above-mentioned change area, the image contrast ρ between the upper pattern area and the lower pattern area is determined.
It may be determined based on. As described above, until the mask data 235 is created in the inspection condition optimization unit 27c.
It is assumed that the image comparison unit 53 does not execute the inspection.

Next, when an object to be inspected (wafer) is actually inspected, the operation is the same as that of the embodiment shown in FIG. That is, the scanning controller 4 controls the stage 46 in accordance with a command from the overall controller 26 while driving the inspection object (wafer) in the Y direction at a predetermined speed under the control of the stage controller 50.
7 scans the electron beam from the electron beam source 14 in the X direction using the beam deflector 15 under the control of the sensor 11.
A continuous two-dimensional image signal in which a chip, a block, or a unit area is repeated is detected from the (secondary electron detector 16), and is converted into a two-dimensional digital image signal by the A / D converter 24. Next, in the image comparing means 53, the detected two-dimensional digital image signal and the first two-dimensional digital image signal stored in the image memory 52 are stored.
When comparing image signals that are originally expected to be the same (for example, for each repeated chip, block, or unit area) among the two-dimensional digital image signals, the mask data 235 stored in the memory 234 is used. The deflection amount (scanning amount) of the electron beam which is read out and given from the scanning control unit 47 to the beam deflector 15 and the stage control unit 50
The read mask data 235 is aligned with the first two-dimensional digital image signal to be compared based on the data (position information) 221 of the displacement amount (travel amount) for moving the stage by the mask data 235. The inspection criterion (determination criterion) is changed between the changed area and the other area based on the information, and a portion where the image signals are different from each other is determined as a defect, and is recorded in the memory in the image processing unit 25 or the overall control unit 26. That is, in the image comparison means 53,
When comparing image signals that are originally expected to be the same (for example, for each repeated chip or block or unit area), inspection is performed based on the mask data 235 in a change area due to charge-up and in other areas. By changing the criterion (criterion) (for example, reducing the sensitivity in a change area due to charge-up), erroneous detection can be prevented even if a change occurs in a digital image signal detected by charge-up.

As shown in FIGS. 6 and 17, since the change area due to the charge-up changes mainly in relation to the scanning direction in which the electron beam is scanned at a high speed, for example, the sample table 21 is set at 90 degrees or 180 degrees. By rotating the object to be inspected 20 by 90 or 180 degrees by rotating it, the scanning direction of the electron beam is changed, and a continuous two-dimensional image signal is detected again from the sensor 11 (secondary electron detector 16). By converting into a two-dimensional digital image signal by the / D converter 24 and inspecting by the image processing unit 25, it is possible to inspect over the entire area with the same inspection criterion (determination criterion).

FIG. 24 is a view showing an eighth embodiment of a system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention. In the eighth embodiment shown in FIG. 24, the sensor 11 (secondary electron detector 16) performs two-dimensional scanning while reciprocally scanning or twice scanning an electron beam on the same line on the surface of the inspection object. 2 shows a case in which a continuous two-dimensional image signal in which a chip, a block, or a unit area is repeated is detected from A and is converted into a two-dimensional digital image signal by the A / D converter 24. 241 is
This is a memory configured by a shift register or the like that stores a digital image signal of one scanning line obtained from the A / D converter 24 in the reciprocating scanning or the double scanning. An image addition circuit 242 adds the digital image signal of one scanning line from the memory 241 and the digital image signal of one scanning line obtained from the A / D converter 24. In the case of reciprocal scanning, the memory 2
It is necessary to invert and read out the digital image signal of one scanning line from the point 41 by 180 degrees. A gate circuit 243 is a circuit that is closed during the reciprocating scan or the first of the two scans.

In the embodiment shown in FIG. 24, the inspection object 20 (28) is loaded,
The stage 46 is controlled by the stage control unit 50
After the alignment by the control from
For a certain chip, block, or unit area (including a pattern) on zero, two-dimensional scanning is performed by reciprocating scanning or scanning twice with the electron beam.
A continuous two-dimensional image signal is detected from the (secondary electron detector 16) while reciprocating scanning or scanning twice, and is converted into a two-dimensional digital image signal while reciprocating scanning or scanning twice by the A / D converter 24. Converted, CP of inspection condition optimization unit 27d
In the charge-up determination unit 233 composed of U or the like, the two-dimensional digital image signal based on the previous scan line in the reciprocal scan or the double scan obtained from the memory 241 and A
The difference between the two-dimensional digital image signal based on the reciprocating scan or the two subsequent scans obtained from the / D converter 24 and the two-dimensional digital image signal is calculated, and two-dimensional mask data (mask signal) indicating a change area due to charge-up is calculated. (For example, FIG. 6D
(E) and shown in FIG.
4 is stored. However, it is possible to apply a process of enlarging only the change area to two-dimensional mask data (mask signal) indicating a change area due to charge-up and store the result in the memory 234 as mask data (mask signal) 235. desirable. Next, the object to be inspected (wafer)
Is the same as the embodiment shown in FIGS. 22 and 23. Since the two-dimensional digital image signal to be inspected is added by the adding circuit 242, the S / N ratio is improved, and a highly reliable inspection can be realized. However, the electron beam scanning becomes complicated, and it is necessary to accurately align digital image signals obtained by reciprocal scanning or double scanning.

FIG. 25 is a diagram showing a ninth embodiment of the system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention. In the ninth embodiment shown in FIG. 25, the image comparison means 254 compares image signals that are originally expected to be the same (for example, for each repeated chip or block or unit area), and determines that they are not coincident with each other. , And each of the compared two images including the defect candidate is cut out by each of the cutout circuits 255 and 256, and is temporarily stored in each of the image memories 257 and 258.
In 9, the charge-up is considered by changing the inspection reference (judgment criterion) using two-dimensional mask data (mask signal) indicating a change area due to the charge-up obtained from the inspection condition setting unit 28, and the true charge-up is considered. This enables inspection of minute defects and the like. That is, the delay circuit 2
Reference numeral 51 denotes a chip for delaying a digital image signal by a repeated chip or block or unit area, and is constituted by, for example, a shift register. Image memory 25
Each of 2, 253 stores a digital image of a certain area composed of a plurality of scanning lines. Image comparison means 25
Numeral 4 compares the digital image signals, which are originally expected to be the same, stored in the image memories 252 and 253, respectively, and extracts defect candidates as mismatches. Each of the extraction circuits 255 and 256 is provided with an image comparison unit 254.
Each of the digital image signals including the defect candidates extracted in step (1) is cut out from each of the image memories 252 and 253 and stored in each of the image memories 257 and 258. The detailed analysis means 259 includes an image memory 257,
Each of the digital images cut out to include each of the defect candidates 258 is inspected using a two-dimensional mask data (mask signal) indicating a change area due to charge-up obtained from the inspection condition setting unit 28, and the like. ) Can be changed and a detailed analysis can be performed to inspect true fine defects and the like. According to this embodiment, when detailed analysis takes time, the sensor 11 (the secondary electron detector 1) is used.
Without synchronizing with the occurrence of the image detected from 6)
True minute defects can be inspected without being greatly affected by charge-up. In particular, in order to find true fine defects, etc., it is necessary to perform positioning more accurately than the fine defect size for detecting digital images, and for that purpose, position shift detection is also necessary, and furthermore, using multiple parameters Inspection criteria (judgment criteria) prepared according to the extracted features
It is necessary to make a determination based on the above, and the detailed analysis requires time.

FIG. 26 is a diagram showing a tenth embodiment of a system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention. For example, as shown in FIG. 5 (b), when a pattern is detected in a reduced manner in a detected image due to charge-up,
For example, when comparing repeated image signals for each chip, block, or unit area, the pattern is reduced in the same way for the compared image signals, so that a defect as mismatch can be detected. However, when extracting a structural feature of a pattern dimension (line width, thickness, etc.), if a change occurs in an image detected by charge-up, the structural feature is extracted in accordance with the change. It is necessary to change the parameters to perform.

In the tenth embodiment in this case,
This will be described with reference to FIG. A reference target (reference sample) whose dimensions are measured by another method and which are the same as the surface cross-sectional structure of the object to be inspected (particularly the same as the material), are set on the sample stage 21, and the reference target is The line is scanned two-dimensionally and irradiated to detect a two-dimensional image signal from the sensor 11 (secondary electron detector 16), and is converted into a two-dimensional digital image signal by the A / D converter 24, so that the inspection condition is appropriate. The conversion unit 27a calculates a feature amount such as a dimension of the reference target based on the converted two-dimensional digital image signal, obtains a difference between the feature amount such as the dimension of the known reference target, and obtains a difference between the feature amount and the known feature amount, for example, as shown in FIG. As shown in b), a change rate of a feature amount such as a pattern reduction rate due to charge-up is calculated and stored in the external storage device 137 or the like. When there are many surface cross-sectional structures of the inspection object, the number of reference targets to be prepared in groups is reduced, and within that group, interpolation or correction is performed using the design information of the surface cross-sectional structure of the inspection object. Just fine.

The inspection condition setting unit 28 reads and sets the rate of change 264 of the characteristic amount according to the surface sectional structure of the inspection object. In the image processing unit 25, various parameters for extracting structural features such as pattern dimensions (line width, thickness, etc.) according to the type of the surface cross-sectional structure of the inspection object are input to various parameter setting means 261. Is stored. The correction unit 262 specifies the type of the object to be inspected, so that various parameter setting units 261 are provided.
A parameter suitable for the type of a desired inspection object is read out from various parameters for extracting a structural feature such as a dimension of a pattern stored in the memory, and the read-out parameter is changed according to a change rate 264 of a feature amount. To perform the correction. The structural characteristic amount extracting means 263 converts the characteristic amount (pattern) of the sectional structure of the surface from the two-dimensional digital image signal of the inspection object 20 (28) obtained from the A / D converter 24 based on the corrected parameter. , Etc.) are extracted. That is, the structural feature extraction means 263
The data (position information) of the deflection amount (scanning amount) of the electron beam given from the scanning control unit 47 to the beam deflector 15 and the displacement amount (running amount) for moving the stage by the stage control unit 50 (on the inspection object) (Indicating the position coordinates) 22
1, a feature value of the cross-sectional structure of the surface of the inspection object is extracted. As described above, the structural feature amount extraction means 263
In the above, by correcting the parameter for extracting the structural feature, the structural feature on the surface of the inspection object 20 (28) is taken into account in consideration of the phenomenon of charge-up occurring on the surface of the inspection object 20 (28). Can be extracted. Further, the inspection can be executed by comparing the structural feature amounts (pattern dimensions and the like) extracted by the structural feature amount extracting unit 263 with an inspection standard (judgment standard).

The eleventh embodiment of the system for detecting a pattern on an object such as a semiconductor wafer using an electron beam according to the present invention.
This embodiment will be described with reference to FIG. 14 is an electron beam source, 15 is a beam deflector, and 16 is a secondary electron detector. Reference numeral 21 ′ denotes a wafer chuck that supports the inspection target object 20 such as a wafer with a needle 272 that is grounded.
Therefore, the electric charge charged on the inspection object 20 is changed to the needle 272.
Escaping, and the phenomenon of charge-up relaxation occurs. 46 is an XY stage. 271
Is a position monitor length measuring device that detects the position of the XY stage 46 and the position coordinates on the inspection object 20. 273
Is an electron shower generator, which sprays an electron shower onto the inspection object 20 to the extent that secondary electrons are not generated, neutralizes the positively charged state, and prevents charge up. is there. Reference numeral 274 denotes an ion shower generator which sprays an ion shower onto the inspection target object 20 to such an extent that secondary electrons are not generated, thereby neutralizing the negatively charged state and preventing the charge up from occurring. It is. Reference numeral 275 denotes a mesh electrode to which a negative potential is applied, and a secondary electrode generated from the surface of the inspection object 20 when a focused electron beam (electron beam) 5 is irradiated to a desired portion of the inspection object 20. The electron is properly detected by the secondary electron detector 16.
This is provided for detection by. Reference numeral 24 'denotes an image input unit for inputting a two-dimensional secondary electron image signal detected by the secondary electron detector 16, and includes an A / D converter 24. Reference numeral 25 denotes an image processing unit having an image memory 52, an image comparison unit 53, and the like. An object to be inspected obtained from the two-dimensional secondary electron image signal input to the image input unit 24 'and the length monitor 271 for position monitoring. Inspection of the upper pattern or the like is performed based on the position coordinates on the upper surface 20. Reference numeral 26 denotes a control computer (overall control unit) which controls the beam deflector 15, X-
It controls the voltage applied to the Y stage 46, the electron shower generator 273, the ion shower generator 274, and the mesh electrode 275. In particular, the control computer (overall control unit) 26 affects the secondary electron signal detected by the secondary electron detector 16 by the electrons and ions sprayed by the electron shower generator 273 and the ion shower generator 274. It is necessary to control it not to be.

The eleventh embodiment can be applied to the first to tenth embodiments. That is, in the first to tenth embodiments, the electric charge accumulated on the surface of the object 20 is neutralized by the electrons and ions sprayed by the electron shower generator 273 and the ion shower generator 274. For example, the contrast in a detected image based on secondary electrons or reflected electrons can be kept substantially constant in time. FIG. 21 shows a schematic configuration of a manufacturing system in which a wafer (semiconductor substrate) 212 is put into a manufacturing line 211 and manufactured using a number of manufacturing facilities 1 to n. 213
Are various manufacturing conditions (including manufacturing lots) input from terminals 2141 to n provided corresponding to a large number of manufacturing facilities 1 to n constituting a manufacturing line, a quality inspection device 215, and an intermediate visual inspection device 216. And a quality management network that manages quality data inspected by the probe tester 217 and the like, and is connected to a quality management computer (not shown). A control device provided in the manufacturing facility may be directly connected to the quality control network 213.

The quality inspection device 215 is an inspection device for inspecting a wafer 212 manufactured up to a desired manufacturing device at least in units of lots, such as a foreign matter defect and a dimension measurement. Also, an inspection device using an electron beam according to the present invention can be applied. The quality inspection device 215 may perform in-line at least a lot unit for the wafer 212 manufactured up to a desired manufacturing device. Here, the inspection apparatus using the electron beam according to the present invention is also applied to the dimension measurement of the exposed and developed resist pattern (having transparency to light) and the like, thereby achieving higher precision than the optical system. Measurement test results can be obtained. In the intermediate visual inspection device 216,
An optical inspection is performed by an inspection apparatus for inspecting a wiring pattern formed on the surface of the wafer or an insulating film pattern formed with through holes in at least a lot unit for the wafer 212 manufactured to a desired manufacturing apparatus. An inspection device and an inspection device using an electron beam according to the present invention can also be applied. The intermediate visual inspection device 216 is also a quality inspection device 215.
Similarly to the above, in-line may be performed on at least a lot unit for the wafer 212 manufactured up to a desired manufacturing apparatus. In this case, by applying the inspection apparatus using the electron beam according to the present invention to the defect inspection of the insulating film pattern or the like in which the through hole is formed, it is possible to obtain a defect inspection result with higher precision than the optical method.

[0097] The probe tester 217 is an apparatus for inspecting the electrical characteristics of all the IC chips formed on the completed wafer. Therefore, the probe tester 217 detects a defective item for each chip on the wafer. The quality control computer obtains inspection results obtained from the quality inspection device 215, the intermediate appearance inspection device 216, and the probe tester 217 via the quality management network 213, and estimates the cause of the defect by analyzing the inspection results.
The manufacturing process (manufacturing apparatus) that causes the cause of the failure is specified, the information is reported to the terminal of the manufacturing apparatus, and the manufacturing conditions are changed or corrected so that the failure does not occur.

That is, a film forming dry process for forming an insulating film such as an interlayer insulating film and a protective film and a wiring metal film on a semiconductor substrate (wafer), an insulating film pattern having a wiring pattern, a through hole, and the like are performed. An etching dry process to form, an exposure and development process to form a resist pattern by applying and exposing and developing a resist, a resist removing process,
A semiconductor is manufactured through a planarization process for planarizing an insulating film and the like, a cleaning process, and the like. Therefore, a semiconductor manufacturing line is configured by arranging a large number of manufacturing apparatuses 1 to n each having various processing apparatuses for realizing each of the above processes and a control apparatus for controlling each processing apparatus. Then, the inspection apparatus using the electron beam according to the present invention is installed between the desired manufacturing apparatuses, and the inspection apparatus inspects a pattern on a wafer manufactured by the manufacturing apparatus. 213 to the computer for quality control,
The quality control computer investigates the cause of the defect based on the inspection data and the past quality control data, and reports the defect to the terminal of the manufacturing facility that has induced the defect. The terminal receiving the report performs countermeasure control according to the cause of the defect on the manufacturing equipment. The production conditions (process conditions) are changed or corrected (including cleaning), that is, control is performed so that no defect occurs.

[0099]

According to the present invention, the inspection conditions suitable for the surface cross-sectional structure of the object are set by reducing the phenomenon of charge-up and the relaxation of the charge-up when the object is irradiated with an electron beam. Thus, it is possible to perform highly reliable inspection, measurement, image display, and the like on the object.

Further, according to the present invention, inspection conditions suitable for a phenomenon of charge-up and a phenomenon of relaxation of charge-up generated when an object is irradiated with an electron beam are set so that the object has high reliability. An effect that inspection, measurement, display of an image, and the like can be performed is achieved. Further, according to the present invention, a semiconductor substrate that is being manufactured in a semiconductor manufacturing line can be actually inspected. A highly reliable semiconductor can be stably produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between an acceleration voltage E and a secondary electron emission efficiency η for a plurality of materials according to the present invention.

FIG. 2 is a diagram showing an embodiment of a detected image when the secondary electron emission efficiency η is close to a plurality of materials by setting an acceleration voltage to approximately Ea as shown in FIG.

FIG. 3 shows a material A (upper pattern) and a material B according to the present invention.
FIG. 11 is a schematic cross-sectional view showing a situation where a material A (upper pattern) is positively charged by irradiating an object having a surface cross-sectional structure consisting of (lower pattern) with an electron beam.

FIG. 4 is a diagram for explaining that a small defect is detected in a detected image when a material A (upper pattern) is positively charged up, as shown in FIG. 3;

FIG. 5 is a diagram for explaining that an upper pattern is reduced in a detected image when a material A (upper pattern) is positively charged up.

FIG. 6 is a diagram showing that a charge-up effect appears in a detected image in relation to a high-speed scanning direction of an electron beam when a material A (upper pattern) is positively charged up and a mask signal.

FIG. 7 shows a material A (upper pattern) and a material B according to the present invention.
FIG. 9 is a schematic cross-sectional view showing a situation in which a material A (upper pattern) is negatively charged by irradiating an object having a surface cross-sectional structure consisting of (lower pattern) with an electron beam.

FIG. 8 is a diagram showing that a decrease in contrast appears as an effect of charge-up in a detected image when a material A (upper pattern) is negatively charged-up and a mask signal.

FIG. 9 is a diagram for explaining that when a material A (upper pattern) is negatively charged up, the detection image changes according to the number of electron beam scans.

FIG. 10 is a diagram showing a change in the secondary electron emission rate η when a positive and negative potential gradient α is applied to a material according to the present invention.

FIG. 11 shows a proper acceleration voltage E and a proper potential gradient so as to reduce the occurrence of charge-up when the upper pattern, which is the surface cross-sectional structure of the object according to the present invention, is made of material A and the lower pattern is made of material B. FIG. 4 is a diagram for describing an embodiment for setting α.

FIG. 12 shows a proper acceleration voltage E and a proper potential gradient so as to reduce the occurrence of charge-up when the upper pattern, which is the surface sectional structure of the object according to the present invention, is made of material B and the lower pattern is made of material A. FIG. 4 is a diagram for describing an embodiment for setting α.

FIG. 13 is a diagram showing a first embodiment of a system for detecting a pattern on an object according to the present invention.

FIG. 14 is a diagram for explaining various sequences in the system for detecting a pattern on an object according to the present invention.

FIG. 15 is a schematic configuration diagram showing an embodiment of a hardware configuration of an inspection condition optimizing unit and an inspection condition setting unit according to the present invention.

FIG. 16 is a diagram showing a second embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 17 is a diagram for explaining a phenomenon of charge-up occurring on the downstream side of a pattern as a detected image signal in the case of reciprocating scanning with an electron beam.

FIG. 18 is a diagram showing a third embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 19 is a diagram showing a fourth embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 20 is a diagram showing a fifth embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 21 is a diagram showing one embodiment of a semiconductor manufacturing line according to the present invention.

FIG. 22 is a diagram showing a sixth embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 23 is a diagram showing a seventh embodiment of the system for detecting a pattern on an object according to the present invention.

FIG. 24 is a diagram showing an eighth embodiment of a system for detecting a pattern on an object according to the present invention.

FIG. 25 is a diagram showing a ninth embodiment of a system for detecting a pattern on an object according to the present invention.

FIG. 26 is a diagram showing a tenth embodiment of a system for detecting a pattern on an object according to the present invention.

FIG. 27 is a diagram showing an eleventh embodiment of the system for detecting a pattern on an object according to the present invention.

[Explanation of symbols]

1 Material A (upper pattern), 2 Material B (lower pattern), 3 Material A (upper pattern), 4 Material B (lower pattern), 5 electron beam, 6 secondary electron, 7 defect , 8
... Material A (upper pattern), 9 ... Material B (lower pattern), 11 ... sensor (secondary electron detector), 13 ... height detection sensor, 14 ... electron beam source, 15 ... beam deflector, 16
... Secondary electron detector, 17 ... ExB, 18 ... Objective lens, 19 ... Electrical potential applying means (grid etc.), 20 ... Object (inspected object), 21 ... Sample table, 22 ... Focal position controller, 23 ... potential control unit, 24 ... A / D converter, 25 ...
Image processing unit, 26: Overall control unit (control computer), 28
... wafer, 27, 27a, 27b, 27c, 27d ... inspection condition optimization unit, 28 ... inspection condition setting unit, 45 ... vacuum sample chamber, 46 ... stage, 47 ... scanning control unit, 48 ... grid voltage adjustment, 49 ... Sample stage potential adjustment, 50: Stage controller, 51: Source potential adjustment, 52: Image memory, 53
... image comparing means, 54 ... image display unit, 55 ... monitor, 5
6 Measurement processing unit, 71 Secondary electrons, 72 Negative equipotential line, 73 Equipotential line of 0 V, 131 CPU, 132
ROM, 133: image memory, 134: RAM, 135
... input means (keyboard, mouse, etc.), 136 ... display means (monitor), 137 ... external storage device, 138 ... CAD
Data, 211: production line, 212: wafer, 213
... Quality management network, 214 ... Terminal, 215 ... Quality inspection device, 216 ... Intermediate appearance inspection device, 217 ... Probe tester, 232 ... Image memory, 234 ... Memory, 23
5 mask data, 241 memory, 242 image addition circuit, 243 gate circuit, 251 delay circuit, 254
... Image comparison means, 255, 256.
7, 258: Image memory, 259: Detailed analysis means, 26
3 ... Structural feature extraction means, 271: Position monitor length measuring device, 273 ... Electronic shower generator, 274 ... Ion shower generator.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Watanabe 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Research Institute (72) Inventor Asahiro Kuni 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Address Co., Ltd.Production Technology Laboratory, Hitachi, Ltd. (72) Inventor Yukio Matsuyama 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Production Technology Laboratory, Hitachi, Ltd. (72) Inventor Yuji Takagi, Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture 292-machi, Hitachi, Ltd.Production Technology Laboratory (72) Inventor Hiroyuki Shinada 1-280 Higashi-Koigabo, Kokubunji-shi, Tokyo Tokyo, Japan Inside (72) Inventor Mari Mari Nozoe 1-280, Higashi-Koigabo, Kokubunji-shi, Tokyo Address Central Research Laboratory, Hitachi, Ltd. (72) Inventor Yutoshi Sugimoto, Tokyo 2326 Imai, Ome-shi F-term in Hitachi, Ltd. Device Development Center (Reference) 2G001 AA03 BA07 CA03 FA03 FA06 GA04 GA05 GA06 HA01 HA07 HA09 HA13 JA02 JA03 JA11 JA12 JA13 JA15 KA03 LA11 MA05 PA01 PA02 PA11 SA06 4M106 AA01 AA10 BA02 CA38 DB05 DE01 DE03 DE04 DE21 DH24 DJ11 DJ21 DJ23

Claims (11)

[Claims] An object is irradiated with an electron beam,
The sensor detects the physical change generated from the object,
An electron beam inspection method characterized by inspecting or measuring an object based on an inspection condition corresponding to a charge-up phenomenon on the surface of the object from a signal indicating the detected physical change. 2. An object is irradiated with an electron beam,
The sensor detects the physical change generated from the object,
From the signal indicating the detected physical change, inspection or measurement of the object is performed based on the inspection condition corresponding to the phenomenon of charge-up of the surface corresponding to the type or change of the cross-sectional structure on the surface of the object. An electron beam inspection method characterized by performing. 3. An object is irradiated with an electron beam,
The sensor detects the physical change generated from the object,
An electron beam inspection method for extracting a structural feature of the object from a signal indicating the detected physical change based on a feature extraction parameter corresponding to a charge-up phenomenon on the surface of the object. Method. 4. An object is irradiated with an electron beam,
The sensor detects the physical change generated from the object,
From the signal indicating the detected physical change, the structural feature of the object is determined based on a feature extraction parameter corresponding to a phenomenon of charge-up of the surface corresponding to the type or change of the sectional structure on the surface of the object. An electron beam type inspection method, characterized by extracting the following. 5. An electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And a sensor for detecting a physical change generated from the object when the object is irradiated with an electron beam, and an inspection condition corresponding to a charge-up phenomenon on the surface of the object. Inspection condition creating means, and image processing means for inspecting or measuring an object based on an inspection condition created by the inspection condition creating means from a signal indicating a physical change detected from the sensor. An electron beam inspection apparatus characterized by the above-mentioned. 6. An electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. And a sensor that detects a physical change generated from the object when the object is irradiated with an electron beam, and a surface of the object corresponding to the type or change of the cross-sectional structure on the surface of the object. An inspection condition creating means for creating an inspection condition corresponding to a charge-up phenomenon; and an object based on an inspection condition created by the inspection condition creating means from a signal indicating a physical change detected from the sensor. An electron beam type inspection apparatus comprising: an image processing means for performing inspection or measurement. 7. An electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. Creates a sensor that detects physical changes that occur from an object when the object is irradiated with an electron beam, and creates feature extraction parameters corresponding to the phenomenon of charge-up on the surface of the object. Image processing for extracting a structural feature of an object from a signal indicating a physical change detected from the sensor based on the feature extraction parameter created by the preceding feature extraction parameter creating unit And an electron beam inspection apparatus. 8. An electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. Means for precharging or discharging the surface of the object, a sensor for detecting a physical change generated from the object when the object is irradiated with an electron beam, and An electron beam inspection apparatus comprising: an image processing unit that inspects or measures an object based on an inspection condition from a signal indicating a detected physical change. 9. An electron beam source, a beam deflector for deflecting an electron beam emitted from the electron beam source, and an objective lens for focusing the electron beam emitted from the electron beam source on an object. Means for precharging or discharging the surface of the object, a sensor for detecting a physical change generated from the object when the object is irradiated with an electron beam, and An electron beam inspection apparatus, comprising: an image processing unit that extracts a structural feature of an object based on a feature extraction parameter from a signal indicating a detected physical change. 10. A semiconductor substrate is irradiated with an electron beam, a physical change generated from the semiconductor substrate is detected by a sensor, and charge on the surface of the semiconductor substrate is detected from a signal indicating the detected physical change. A method for manufacturing a semiconductor, comprising: performing inspection or measurement on a semiconductor substrate based on an inspection condition corresponding to an up phenomenon to manufacture a semiconductor substrate. 11. The method according to claim 10, wherein said inspection or measurement result is analyzed and fed back to a predetermined process.