JPH10144248A - Electron beam detection method, electron beam detection method for scanning type electron microscope, dimension calibration method for scanning type electron microscope, and dimension calibration device for electron beam detection device and scanning type electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimension calibration method with low dispersion for a scanning type microscope. SOLUTION: A switching element which is equipped with a gate electrode 12 whose stripe shape is exposed in the top view, and is also equipped with a MOS FET structure permitting source drain current to start flowing with switching operated upon irradiating an electron beam onto the aforesaid gate electrode 12, is rested over the specimen table of a scanning type electron microscope, and the source drain current of the switching element 10 is thereby detected. By this constitution, the scanning time is thereby measured from the time when the gate electrode 12 is canned once by an electron beam till the time when the gate electrode 12 is scanned again next time by the electron beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an electron beam and a method for calibrating a dimension of a scanning electron microscope having a dimension measuring mechanism.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as highly integrated circuits, it is necessary to know the dimensions of the pattern of each part of the manufactured semiconductor device. In measuring the dimension of the pattern, a scanning electron microscope (hereinafter, also referred to as SEM) having a dimension measuring mechanism is used as a dimension measuring device.

When using an SEM as a dimension measuring device, it is necessary to calibrate the dimension of the SEM using a reference sample whose dimensions are known before measuring the dimensions. When calibrating the dimensions, an electron microscope image (SEM) of the reference sample projected on the screen of the SEM
The measurer counts the number of dots (pixels) occupied by the image) on the screen, and corrects the converted value between the number of dots on the screen and the size of the sample to be measured.

As a reference sample, a polycrystalline silicon film formed in a stripe shape or a sample obtained by etching an aluminum (Al) or tungsten (W) compound is usually used.

[0005]

However, the SEM
The outline of the image of the reference sample displayed on the screen is not always clear. For this reason, an error occurs when counting the number of dots in the image of the reference sample. Further, the counted number of dots varies among the measurers. For this reason,
When an image projected on a screen is used, there is a problem that dimensional calibration varies.

Therefore, in order to reduce variations in dimensional calibration due to unclear image outlines, it is conceivable to perform dimensional calibration using image processing technology. In performing the image processing, first, a screen is formed by using a signal detected by the secondary electron detector of the SEM as a pixel, and the brightness is represented by digitizing the signal intensity. Next, an appropriate brightness value is set as a threshold value. Then, the contour of the image is sharpened by cutting the image of the portion having the brightness less than the threshold value.

However, the performance of the secondary electron detector and the CRT for displaying an image is not completely the same between individual SEMs. In addition, there is a possibility that an error may occur when the brightness is digitized. Therefore, when image processing is performed,
This causes variations in dimensional calibration.

For this reason, there has been a demand for a method and a device for calibrating dimensions of a scanning electron microscope with less variation.

In a dimension measuring apparatus using a scanning electron microscope, a sample to be measured, such as a reference sample, is scanned with an electron beam.
An SEM image of the sample to be measured is obtained. The number of dots occupied by the SEM image of the measured sample on the screen is determined by the irradiation time during which the electron beam scans the measured sample and irradiates the measured sample. The irradiation time is determined by the scanning speed of the electron beam.

The inventor of the present application has conducted various studies and experiments to detect variations in the scanning speed of the electron beam without counting the number of dots in the SEM image of the reference sample in dimension calibration. I came up with dimensional calibration.

However, means for detecting an electron beam of a scanning electron microscope has not been known. Therefore, realization of a means for detecting an electron beam has been desired.

[0012]

[Means for Solving the Problems]

(First Invention) According to the electron beam detection method of the first invention of the present application, when an exposed control electrode is irradiated with an electron beam, an electric signal output from a switching element that performs a switching operation is detected. Thus, the method is characterized in that an electron beam is detected.

As described above, according to the electron beam detecting method of the first invention, by irradiating the control electrode of the switching element with the electron beam, the electron beam is detected as an electric signal output from the switching element. Can be.

(Embodiment 2) According to the electron beam detecting method of the scanning electron microscope of the second invention, the switching element which performs a switching operation when the exposed control electrode is irradiated with the electron beam is scanned. The electron beam is mounted on a sample stage of a scanning electron microscope so that the electron beam scans over the control electrode, and the electric signal output from the switching element is detected to detect the electron beam. .

As described above, according to the electron beam detecting method of the scanning electron microscope of the second invention, the control electrode of the switching element mounted on the sample stage of the scanning electron microscope is irradiated with the electron beam. Accordingly, an electron beam can be detected as an electric signal output from the switching element.

Further, in the electron beam detecting method for a scanning electron microscope according to the second invention, preferably, a switching element having a MOS FET structure is used as the switching element, and a gate electrode of the MOS FET structure is exposed as a control electrode. Using the part that has been
It is preferable to detect a current between the source region and the drain region of the OSFET structure (hereinafter, also referred to as a source / drain current).

When a switching element having a MOS FET structure is used, when a voltage is applied to the gate electrode by irradiating the gate electrode with an electron beam, the MOS
The source / drain current of the FET changes. Therefore, by detecting this source / drain current,
An electron beam can be detected. Since the application of the voltage to the gate electrode is performed by irradiating an electron beam, a wiring electrode connected to the gate electrode of a normal MOS FET is not required.

By the way, in a normal MOS FET element, the gate electrode is covered with a passivation film (insulating protective film). Therefore, even if the normal MOS FET element is irradiated with an electron beam, the MOS FET element operates. I can't let that happen.

(Third Invention) According to the method for calibrating dimensions of a scanning electron microscope according to the third invention, a switching operation is performed when an electron beam is applied to an exposed control electrode in a stripe shape when viewed from above. The switching element is mounted on a sample stage of a scanning electron microscope so that the electron beam scans over the control electrode, and the electron beam is controlled by detecting an electric signal output from the switching element. It is characterized in that the time from scanning the electrode to the next scanning of the control electrode is measured.

As described above, according to the method for calibrating dimensions of a scanning electron microscope according to the third aspect of the present invention, the control electrode of the switching element mounted on the sample stage of the scanning electron microscope is irradiated with the electron beam. Detecting an electron beam as an electric signal output from the switching element,
From this electric signal, the time from when the electron beam scans the control electrode until the next scan of the control electrode (hereinafter, also referred to as a scanning time) is measured. As a result, it is possible to measure the scanning time, which is the time required for the electron beam to scan in one scan for each scan of the electron beam.
Then, the variation in the scanning time can be known.
In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

In the third aspect of the present invention, even if the dimensions of the switching elements are not accurately known, the dimensions can be calibrated relatively.

Further, according to the dimension calibration method of the scanning electron microscope of the third invention, the dimension calibration is performed directly by detecting the electron beam, so that it is not necessary to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

Further, according to the method for calibrating dimensions of a scanning electron microscope of the third invention, it is not necessary to use an SEM image of a reference sample, so that the secondary electron detector of the SEM and the performance of a CRT for displaying an image are not required. Not affected by variation. For this reason, in dimension calibration, it is possible to reduce variation in dimension calibration between SEMs.

Further, according to the method for calibrating dimensions of a scanning electron microscope of the third invention, it is possible to use a switching element made of a material having electron beam resistance higher than that of a conventional photoresist-made reference sample.

In the method for calibrating dimensions of a scanning electron microscope according to the third aspect of the present invention, preferably, a plurality of control electrodes are arranged separately from each other, and after the electron beam scans one control electrode, another control electrode is controlled. It is preferable to measure a scanning time, which is a time required for scanning the electrodes.

As described above, by measuring the scanning time between a plurality of control electrodes, it is possible to measure not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in a partial region between the control electrodes. can do. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the method for calibrating dimensions of a scanning electron microscope according to the third invention, when a plurality of control electrodes are arranged,
Preferably, three or more control electrodes are arranged separately from each other, and the scanning time between a plurality of different control electrodes is preferably measured.

As described above, if three or more control electrodes are provided and the scan times between the control electrodes in the different partial areas are measured, it is possible to measure the variation in the scan time between the different partial areas. it can.

In the method for calibrating dimensions of a scanning electron microscope according to the third invention, when three or more control electrodes are arranged, preferably one of the control electrodes other than the outermost one is used. Is the reference control electrode, and this reference control electrode is
Place the switching element on the sample stage so that it comes to the position irradiated by the electron beam that has not been deflected,
The scanning time may be measured for each of two control electrodes arranged symmetrically with respect to the reference control electrode.

As described above, by measuring the scan times of the two control electrodes symmetrical with respect to the reference control electrode, the scan times between the reference control electrode and the respective control electrodes can be compared. In addition, it is possible to detect the deviation of the electron beam of the electron microscope.

In the method for calibrating dimensions of a scanning electron microscope according to the third invention, preferably, a switching element having a MOS FET structure is used as a switching element, and a gate electrode having a MOS FET structure is exposed as a control electrode. MOS signal as electric signal
It is preferable to detect a current (source / drain current) between the source region and the drain region of the FET structure.

When a switching element having a MOS FET structure is used, when a voltage is applied to the gate electrode by irradiating the gate electrode with an electron beam, a MOS
The source / drain current of the FET changes. Therefore, by detecting this source / drain current,
An electron beam can be detected. Since the application of the voltage to the gate electrode is performed by irradiating an electron beam, a wiring electrode connected to the gate electrode of a normal MOS FET is not required.

By the way, in a normal MOS FET device, since the gate electrode is covered with a passivation film (insulating protective film), even if the normal MOS FET device is irradiated with an electron beam, the MOS FET device operates. I can't let that happen.

(Fourth Invention) According to the dimension correction method for a scanning electron microscope of the fourth invention, an electron beam is applied to an exposed control electrode having a known stripe-shaped width when viewed from above. A switching element that performs a switching operation is mounted on a sample stage of a scanning electron microscope so that an electron beam scans over the control electrode, and by detecting an electric signal output from the switching element,
The method is characterized in that the time for irradiating the control electrode with the electron beam is measured.

As described above, if the width of the stripe shape of the control electrode is known, the scanning speed of the electron beam can be directly measured by measuring the time during which the electron beam scans the control electrode. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the S
Absolute dimensional calibration of a scanning electron microscope can be performed without using an EM image.

In the method for calibrating dimensions of a scanning electron microscope according to the fourth aspect of the present invention, preferably, a switching element having a MOS FET structure is used as the switching element, and a gate electrode having a MOS FET structure is exposed as a control electrode. MOS signal as electric signal
It is preferable to detect a current (source / drain current) between the source region and the drain region of the FET structure.

When a switching element having a MOS FET structure is used, when a voltage is applied to the gate electrode by irradiating the gate electrode with an electron beam, a MOS
The source / drain current of the FET changes. Therefore, by detecting this source / drain current,
An electron beam can be detected. Since the application of the voltage to the gate electrode is performed by irradiating an electron beam, a wiring electrode connected to the gate electrode of a normal MOS FET is not required.

By the way, in a normal MOS FET element, since the gate electrode is covered with a passivation film (insulating protective film), even if the normal MOS FET element is irradiated with an electron beam, the MOS FET element operates. I can't let that happen.

(Fifth Invention) According to the electron beam detection apparatus of the fifth invention, a switching element that performs a switching operation when an exposed control electrode is irradiated with an electron beam is constituted. It is characterized by the following.

As described above, according to the electron beam detecting apparatus of the fifth invention, by irradiating the control electrode of the switching element with the electron beam, the electron beam can be detected as an electric signal output from the switching element. Can be.

Further, when the switching element of the electron beam detector according to the fifth invention is mounted on the sample stage of the scanning electron microscope and the control electrode of the switching element is irradiated with an electron beam, the output from the switching element is obtained. An electron beam of a scanning electron microscope can be detected as the electric signal to be transmitted.

(Sixth Invention) According to the dimensional calibration apparatus for a scanning electron microscope of the sixth invention, the control electrode is provided with an exposed control electrode having a stripe shape when viewed from above, and the control electrode is provided with an electron beam. Is constituted by a switching element that performs a switching operation when is irradiated.

Then, when the switching element of the dimensional calibration device of the scanning electron microscope according to the sixth invention is mounted on the sample stage of the scanning electron microscope and the control electrode of the switching element is irradiated with an electron beam, An electron beam can be detected as an electric signal output from the switching element. Further, when the time from when the electron beam scans the control electrode to the next scan of the control electrode (hereinafter, also referred to as a scanning time) is measured from the electric signal, it is calculated as 1 for each scan of the electron beam. The scanning time, which is the time required for the electron beam to scan in each scan, can be measured. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, the relative dimensional calibration between the plurality of scanning electron microscopes is performed. Can be.

In the sixth aspect, even if the dimensions of the switching elements are not precisely known, the dimensions can be calibrated relatively.

Further, in the dimensional calibration apparatus for a scanning electron microscope according to the sixth aspect of the present invention, it is preferable that a plurality of control electrodes are arranged separately from each other.

When the scanning time between the plurality of control electrodes is measured, not only the variation in the scanning time of each scanning over the entire scanning width of the electron beam but also the scanning time in the partial region between the control electrodes is obtained. Variation can also be measured. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the dimensioning device for a scanning electron microscope according to the sixth aspect of the present invention, when a plurality of electrodes are arranged, it is preferable to arrange three or more control electrodes separately from each other.

And a plurality of sets of two control electrodes different from each other among the three or more control electrodes,
By measuring the scanning time between the control electrodes in the different partial regions, it is possible to measure the variation in the scanning time between the different partial regions.

Further, one of the control electrodes other than the outermost one of the control electrodes is used as a reference control electrode, and the sample stage is set so that this reference control electrode is located at a position irradiated by an electron beam which is not deflected. When the switching element is placed on the top and the scanning time is measured for each of the two control electrodes arranged symmetrically with respect to the reference control electrode, the two control electrodes which are symmetric with respect to the reference control electrode are measured. , The scanning time between the reference control electrode and each control electrode can be compared with each other to detect the bias of the electron beam of the electron microscope.

Further, in the dimensioning device for a scanning electron microscope according to the sixth invention, preferably, the switching element has a MOS FET structure, and the control electrode is a MOS FET.
It is preferable that the gate electrode has a portion where the gate electrode of the FET structure is exposed.

When a switching element having a MOS FET structure is used, when a voltage is applied to the gate electrode by irradiating the gate electrode with an electron beam, the MOS
The source / drain current of the FET changes. Therefore, by detecting this source / drain current,
An electron beam can be detected. Since the application of the voltage to the gate electrode is performed by irradiating an electron beam, a wiring electrode connected to the gate electrode of a normal MOS FET is not required.

By the way, in a normal MOS FET device, since the gate electrode is covered with a passivation film (insulating protective film), even if the normal MOS FET device is irradiated with an electron beam, the MOS FET device operates. I can't let that happen.

Further, in the dimension correcting apparatus for a scanning electron microscope according to the sixth invention, it is preferable that the width of the stripe shape of the control electrode is known.

If the width of the stripe shape of the control electrode is known, the scanning speed of the electron beam can be directly measured by measuring the time during which the electron beam scans the control electrode. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

(Seventh Invention) According to the electron beam detection method of the seventh invention, the superconducting state is broken by irradiating an electron beam. By detecting the electric resistance of the superconductor, It is characterized by detecting an electron beam.

As described above, according to the electron beam detecting method of the seventh invention, by irradiating the superconductor with the electron beam, the electron beam can be detected as a change in the electric resistance of the superconductor. .

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the seventh aspect, a weaker electron beam can be detected as compared with the case where the switching element is used.

(Eighth Invention) According to the electron beam detection method of the scanning electron microscope of the eighth invention, the superconductor which breaks the superconducting state when irradiated with the electron beam can be scanned by the scanning electron microscope. An electron beam is mounted on a sample stage of a microscope so as to scan over the superconductor, and the electric resistance of the superconductor is detected to detect the electron beam.

As described above, according to the electron beam detecting method of the scanning electron microscope of the eighth invention, the superconductor placed on the sample stage of the scanning electron microscope is irradiated with the electron beam, An electron beam can be detected as a change in the electric resistance of the superconductor.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the eighth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used.

(Ninth Invention) According to the dimensional calibration method for a scanning electron microscope of the ninth invention, the superconducting state is broken when irradiated with an electron beam. The conductor is placed on the stage of the scanning electron microscope.
The electron beam is placed so as to scan the superconductor, and by detecting the electric resistance of the superconductor, the electron beam scans the superconductor until the next scan of the superconductor. The time is measured.

As described above, according to the dimensional correction method for a scanning electron microscope of the ninth invention, the superconductor placed on the sample stage of the scanning electron microscope is irradiated with an electron beam, thereby An electron beam is detected as a change in electric resistance of the superconductor, and a time from the scanning of the control electrode by the electron beam to the next scanning of the control electrode (hereinafter also referred to as a scanning time) is obtained from the electric signal. ) Is measured. As a result, it is possible to measure the scanning time, which is the time required for the electron beam to scan in one scan for each scan of the electron beam. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

In the ninth aspect, even if the dimensions of the superconductor are not accurately known, the dimensions can be calibrated relatively.

Further, according to the dimensional calibration method for a scanning electron microscope of the ninth aspect, since the dimensional calibration is performed directly by detecting the electron beam, there is no need to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

Further, according to the dimensional calibration method of the scanning electron microscope of the ninth invention, it is not necessary to use the SEM image of the reference sample, so that the secondary electron detector of the SEM and the performance of the CRT for displaying the image are not required. Not affected by variation. For this reason, in dimension calibration, it is possible to reduce variation in dimension calibration between SEMs.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the ninth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

Further, according to the dimensional calibration method for a scanning electron microscope of the ninth aspect, a superconductor made of a material having higher electron beam resistance than a conventional photoresist standard sample can be used.

In the dimensional calibration method for a scanning electron microscope according to the ninth aspect of the present invention, preferably, a plurality of superconductors are arranged side by side so as to be separated from each other, and after the electron beam scans one superconductor, another It is good to measure the time between scanning the superconductors.

As described above, when the scanning time of a plurality of superconductors is measured, not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the superconductors is obtained. Can be measured. As a result, the SEM can be calibrated by adjusting the SEM so that the variation in the scanning time between the partial region of the SEM and the entire region is substantially the same.

Further, a plurality of scanning electron microscopes
By adjusting each scanning electron microscope so that the variation of the scanning time in the partial area is substantially the same, the relative dimension calibration of the scanning electron microscope can be performed.

In the dimensional configuration method for a scanning electron microscope according to the ninth aspect, when a plurality of superconductors are arranged, preferably, three or more superconductors are arranged separately from each other and different from each other. The scanning time between a plurality of superconductors may be measured.

As described above, if three or more superconductors are provided and the scanning times between the superconductors in the different partial regions are measured, the variation in the scanning time between the different partial regions is measured. be able to.

By adjusting the scanning electron microscope so that the variation of the scanning time in the plurality of partial regions is substantially the same, it is possible to calibrate the relative dimensions of the scanning electron microscope.

In the method for calibrating dimensions of a scanning electron microscope according to the ninth aspect of the present invention, when three or more superconductors are arranged, preferably, the superconductors other than the outermost superconductor are used. Is placed as a reference superconductor, this reference superconductor is placed at a position irradiated by an electron beam that has not been deflected, and arranged at positions symmetrical with respect to the reference superconductor. The scanning time may be measured for each of the two superconductors.

As described above, when the scanning times of two superconductors which are symmetrical with respect to the reference superconductor are respectively measured, the scanning time between the reference superconductor and each superconductor is determined. By comparing, the bias of the electron beam of the electron microscope can be detected.

(Tenth Invention) According to the dimensional calibration method for a scanning electron microscope of the tenth invention, the superconducting state is broken when irradiated with an electron beam. Is placed on a sample stage of a scanning electron microscope so that the electron beam scans the superconductor, and the electric beam is detected by detecting the electric resistance of the superconductor. It is characterized in that the time for irradiating the superconductor is measured.

As described above, if the width of the stripe shape of the superconductor is known, it is possible to directly measure the scanning speed of the electron beam by measuring the time during which the electron beam scans the superconductor. it can. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the tenth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

(Eleventh invention) According to the eleventh invention, the electron beam detector is constituted by a superconductor whose superconducting state is broken when irradiated with an electron beam. Features.

As described above, according to the electron beam detector of the eleventh aspect, when the superconductor is irradiated with the electron beam, the superconducting state is broken. Can be detected.

Further, when the superconductor as the electron beam detector of the eleventh invention is mounted on a sample stage of a scanning electron microscope and the superconductor is irradiated with an electron beam, the superconducting state is broken. As a change in the electrical resistance of the superconductor,
An electron beam of a scanning electron microscope can be detected.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the eleventh aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

(Twelfth Invention) According to the dimensional calibration apparatus for an electron microscope of the twelfth invention, the superconducting state is broken when irradiated with an electron beam. It is characterized by being constituted by a body.

Then, the superconductor as a dimensional calibration device of the scanning electron microscope of the twelfth invention is placed on a sample stage of the scanning electron microscope, and the superconductor is irradiated with an electron beam. The superconducting state is broken. Therefore, the electron beam can be detected as a change in the electric resistance of the superconductor. Furthermore, from the change in the electric resistance, the time from the time when the electron beam scans the superconductor to the time when the superconductor is next scanned (hereinafter, also referred to as a scanning time) is measured.
The scanning time, which is the time required for the electron beam to scan in each scan of the electron beam, can be measured. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

In the twelfth aspect, even if the dimensions of the switching elements are not accurately known, the dimensions can be calibrated relatively.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the twelfth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect, it is preferable that a plurality of superconductors are arranged side by side with a distance from each other.

When the scanning time between the plurality of superconductors is measured, not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the superconductors is obtained. Can be measured. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect of the invention, when a plurality of superconductors are arranged, it is preferable that three or more superconductors are arranged at a distance from each other.

Then, a plurality of sets of two superconductors different from each other among three or more superconductors are respectively sandwiched.
By measuring the scan times between the superconductors in the different partial regions, it is possible to measure the variation in the scan time between the different partial regions.

Further, one of the superconductors other than the outermost superconductor is used as a reference superconductor, and this reference superconductor comes to a position irradiated by an electron beam which has not been deflected. As described above, when the dimensional configuration device is placed on the sample table and the scanning time is measured for each of the two superconductors arranged symmetrically with respect to the reference superconductor, the reference superconductor is obtained. By measuring the scan times of two superconductors that are symmetrical in between, the scan times between the reference superconductor and each superconductor are compared, and the electron beam bias of the electron microscope is compared. Can be detected.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect, it is preferable that the width of the stripe shape of the superconductor is known.

If the width of the stripe shape of the superconductor is known, it is possible to directly measure the scanning speed of the electron beam by measuring the time during which the electron beam scans the superconductor. it can. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

[0094]

Embodiments of the present invention will be described below with reference to the drawings. The drawings referred to merely schematically show the sizes, shapes, and arrangements of the components to the extent that these inventions can be understood. Therefore, these inventions are not limited only to the illustrated examples.

(First Embodiment) Hereinafter, an electron beam detecting method according to a first invention, an electron beam detecting method using a scanning electron microscope according to a second invention, and a scanning electron according to a third invention according to the present application will be described. An example of a method for calibrating the dimensions of a microscope, an electron beam detecting apparatus according to a fifth invention, and an example of a dimension calibrating apparatus for a scanning electron microscope according to a sixth invention will be described together as a first embodiment.

FIG. 1 is a block diagram for explaining a dimension correcting apparatus for a scanning electron microscope according to the first embodiment.
In addition, this dimension correction device includes an electron beam detection device.

The dimension calibrating apparatus 10 includes a control electrode 12 which is exposed in a stripe shape when viewed from above, and includes a switching element 10 which performs a switching operation when the control electrode 12 is irradiated with an electron beam. It is constituted. The switching element 10 is composed of Si
MOSF formed on (silicon) semiconductor substrate 14
It has an ET structure. The control electrode 12 is a MOS
It is constituted by a portion where the gate electrode 12 of the stripe-shaped polysilicon in the FET structure is exposed. The length a of the short side of the gate electrode 12 having the stripe shape is about 0.3 μm, and the length b of the long side is about 20 μm.
In FIG. 1, the gate electrode 12 is shown with hatching, though not a cross-sectional portion, to facilitate understanding of the drawing.

The MOS FET structure includes a source region 16 and a drain region 18 with the gate electrode 12 interposed therebetween when viewed from above. And the source area 1
A bias voltage is applied between 6 and the drain region 18. Further, the source region 16 and the drain region 1
8 is provided with a source terminal 20 and a drain terminal 22 for extracting an electric signal.

The region including the source region 16 and the drain region 18 is covered with a passivation film except for the gate electrode 12. Therefore, the source region 16 and the drain region 18 are not directly irradiated by the electron beam, but only the gate electrode is irradiated by the electron beam. In FIG. 1, illustration of the passivation film is omitted.

Next, prior to the description of the operation of the dimensional calibration apparatus of the first embodiment, in order to facilitate understanding of the invention, the scanning of an electron beam of a scanning electron microscope (SEM) which is generally used at present. Will be described.

FIG. 2 is a schematic diagram showing the scanning path of the electron beam of the SEM on the surface of the sample to be observed as viewed from the electron beam source side.

The electron beam scans the observation target area indicated by a rectangle 24 in FIG. In FIG. 2, assuming that the horizontal direction of the drawing is the X direction and the vertical direction of the drawing is the Y direction, the electron beam scans the observation target area along the X direction from left to right in the drawing. Then, for each scan along the X direction,
The scanning position is moved by ΔY in the Y direction.

For example, the first scan is performed in the observation area 2
The section from the upper left first point 26 to the upper right second point 28 of the observation target area is scanned. The first scanning section is indicated by a solid arrow 30 in FIG. Next, in the second scan, a section from the third point 32 to the fourth point 34 is scanned. The second scanning section is indicated by an arrow 36 in FIG.
The third point 32 is Y from the first point 26 by ΔY.
Direction, and the fourth point 34 is also
This is a position shifted from the second point 28 in the Y direction by ΔY. Therefore, each scanning section is parallel to each other. In FIG. 2, a moving path 38 from the second point 28 to the third point 32 is indicated by a dotted arrow 38, but the electron beam is not irradiated on this moving path 38.

Thereafter, the observation target area 24 is scanned until the last scan in the same manner as the first and second scans.
The last scan is performed from the fifth point 40 at the lower left of the observation target area 24 to the sixth point 42 at the lower right of the observation target area 24.
Is scanned. In addition, in FIG.
4 is indicated by a solid arrow.

When the electron beam scans the observation target area, secondary electrons are generated. In the electron microscope, the secondary electrons are converted into a sensor such as a photomultiplier tube (not shown).
Was used to obtain SEM images. Conventionally, dimension calibration has been performed using this SEM image.

Next, a method for calibrating the dimensions of the scanning electron microscope according to the first embodiment will be described with reference to FIG. Note that this dimension calibration method includes a method of detecting an electron beam, and also includes a method of detecting an electron beam of a scanning electron microscope. FIG. 3 is a diagram for explaining a method of calibrating the dimensions of the scanning electron microscope according to the first embodiment.

First, the switching element 10 is mounted on a sample stage (not shown) of the scanning electron microscope so that the electron beam scans over the control electrode (gate electrode) 12.

Here, FIG. 3 shows the switching element 10 placed on the sample stage and the scanning section of the electron beam in an overlapping manner. The scanning section of the electron beam in FIG. 3 is the same as the scanning section of the electron beam in FIG.

Then, as shown in FIG. 3, each scanning section of the electron beam crosses over the stripe-shaped gate electrode 12. In FIG. 3, the switching element is placed so that each scanning section vertically crosses the stripe-shaped gate electrode 12, but the extending direction of the gate electrode 12 does not always coincide with the Y direction. You don't have to. In FIG. 3, since the gate electrode 12 is longer than the observation target region 24 in the Y direction, all scan sections of the observation target region 24 cross the gate electrode 12. Only a part of the scanning section 24 may cross over the gate electrode 12.

The conditions of the acceleration voltage and current of the electron beam are preferably the same as those for measuring the dimensions of the sample to be measured.

In the first embodiment, an electric signal output from the switching element 10 is detected. When the gate electrode 12 of the switching element 10 is irradiated with an electron beam, the potential of the gate electrode 12 changes. As a result, the switching element 10 performs a switching operation, and an electric signal between the source region 16 and the drain region 18 changes. In the switching element 10, the intensity of the source / drain current flowing between the source side terminal 20 and the drain side terminal 22 is increased only while the electron beam is irradiating the gate electrode 12.

That is, by irradiating the control electrode 12 of the switching element 10 with the electron beam, the electron beam can be detected as an electric signal output from the switching element 10.

[0113] Upon scanning of the electron beam, the electron beam begins scanning the first scan section 30 from the first point 26, at time t _1, a first first first gate electrode 12 on the scanning section 30 of The first irradiation position 46 which is the edge near the point 26 is irradiated. Then, the electron beam that has passed through the first irradiation position 46 scans the remaining section of the first scanning section 30 to reach the second point 28, and then starts the second scanning section 36 at the start point. Move to 3 points 32.
Then, the second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
The electron beam that has started the scan of No. 6 irradiates the second irradiation position 48 at the time t ₂ , which is the edge of the first gate electrode 12 near the third point 32 on the second scan section 36. Then, the electron beam that has passed through the second irradiation position 48 scans the remaining section of the second scanning section 36 and makes the fourth point 3
Then, the process proceeds to the start point of the third scanning section. Hereinafter, the electron beam is applied to the gate electrode 1 for each scanning section.
2 and the last scanning section is scanned to complete scanning of one screen.

The output of the switching element 10 is shown in the graph of FIG. The horizontal axis of the graph in FIG. 4 represents time (arbitrary unit), and the vertical axis of the graph represents current (arbitrary unit). The waveform of the source / drain current shown by the curve I in the graph of FIG. 4 is a pulse-like waveform.

The first peak P ₁ rising at the time t ₁ among the pulse-like peaks of the curve I is the time during which the electron beam scans the first gate electrode 12 in the first scanning section 30. Corresponding to Also, the time t _{2 of the} curve I
Second peak P ₂ rises, the second scanning section 3
6 corresponds to the time when the electron beam is scanning over the first gate electrode 12.

Further, in the first embodiment, based on the output of the switching element 10, the scanning time from the scanning of the gate electrode 12 by the electron beam to the next scanning of the gate electrode 12 is measured. . In the graph of FIG. 4, as an example of the scanning time, the electron beam irradiates the first irradiation position 46 of the gate electrode 12 in the first scanning section 30 from the time t ₁ to the second scanning section 36 of the gate electrode 12 in the second scanning section 36. 2 Time t ₂ at which the irradiation position 48 was irradiated
The total scanning time T up to is shown.

In addition to the scan time T over the first scan section 30 and the second scan section 36, the scan time over other mutually continuous scan sections (for example, the second scan section and the third scan section). Are respectively measured. As a result, variation in each scanning time can be known. Then, the relative dimensional calibration can be performed by adjusting the scanning electron microscope so that the variation of each scanning time is minimized.

Further, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the relative dimensions of the scanning electron microscope. Can be. As a result, it is possible to reduce variations in measurement dimensions due to differences in the used machines when a plurality of scanning electron microscopes are used.

In this embodiment, even if the dimensions of the stripe shape of the gate electrode 12 are not accurately known, the dimensions can be calibrated relatively.

In the first embodiment, since the dimension correction is performed directly by detecting the electron beam, there is no need to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

In the first embodiment, it is not necessary to use the SEM image of the reference sample.
And is not affected by variations in the performance of secondary electron detectors and CRTs that display images. For this reason, in dimensional calibration,
Variation in dimensional calibration between SEMs can be reduced.

(Second Embodiment) In the second embodiment, an example of the dimension calibration method for a scanning electron microscope according to the fourth invention and an example of the dimension calibration device for the electron microscope according to the sixth invention will be described together. explain.

In the dimension calibration apparatus 10 of the first embodiment, if the dimensions of the stripe-shaped gate electrode 12 are accurately determined, absolute dimension calibration can be performed. For example, when the length a of the short side of the gate electrode 12 of the switching element 10 is known to be exactly 0.3 μm, the switching element 10 is moved so that the scanning section of the electron beam crosses the gate electrode 12 vertically. When placed on the sample stage, the length of the scanning section on the gate electrode 12 is 0.3
μm.

Therefore, by measuring the time τ during which the electron beam scans on the gate electrode 12, the absolute scanning speed of the electron beam in the scanning section can be obtained. In the graph of FIG. 4, the time τ during which the current having the pulse-shaped waveform flows corresponds to the time during which the electron beam scans the gate electrode 12.

Therefore, based on the absolute scanning speed of the electron beam, dimensional calibration in dimensional measurement by a scanning electron microscope can be performed. In addition, if the absolute scanning speed of the electron beam is adjusted to a constant value by adjusting the scanning electron microscope, variations in dimensional measurement in the same machine and variations in dimensional measurement in multiple Reduction can be achieved.

(Third Embodiment) Next, as a third embodiment, a method for calibrating the size of a scanning electron microscope according to the third invention and a device for calibrating the size of a scanning electron microscope according to the sixth invention will be described. An example is also described.

FIG. 5 is a block diagram for explaining a dimension correcting device for a scanning electron microscope according to the third embodiment. The dimensional calibration device 50 includes a first control electrode 52 and a second control electrode 54 that are exposed in a stripe shape when viewed from above, and the two control electrodes 52 and 54 are switched when an electron beam is irradiated. It comprises a switching element 50 that operates. Further, the first control electrode 52 and the second control electrode 54 are spaced apart from each other and arranged in parallel.

This switching element 50 is
MOS formed on i (silicon) semiconductor substrate 14
It has an FET structure. Also, two control electrodes 52
And 54 are constituted by portions exposing the first gate electrode 52 and the second gate electrode 54 of stripe-shaped polysilicon in the MOS FET structure, respectively. The length a of the short side of each of the stripe-shaped gate electrodes 52 and 54 is about 0.3 μm, and the length b of the long side is about 20 μm. The distance c between the first gate electrode 52 and the second gate electrode 54 is about 0.5 μm. still,
In FIG. 5, in order to facilitate understanding of the drawing, each of the gate electrodes 52 and 54 is shown with hatching, though not a cross section.

The MOS FET structure has a first source region 5 with a first gate electrode 52 interposed therebetween when viewed from above.
6 and a drain region 58. Further, a second source region 60 and a drain region 58 are provided with the second gate electrode 54 interposed therebetween. Here, a region sandwiched between the first gate electrode 52 and the second gate electrode 54 is a drain region 58 for both the gate electrodes 52 and 54.
It has become.

A bias voltage is applied between the first source region 56, the second source region 60, and the drain region 58. In the first source region 56, the drain region 58, and the second source region 60, a first source terminal 62, a drain terminal 64, and a second source terminal 66 for extracting an electric signal are provided, respectively.

The region including the first source region 56, the drain region 58, and the second source region 60 is
Except for the gate electrode 52 and the second gate electrode 54, they are covered with a passivation film. Therefore, the first source region 56, the drain region 58, and the second source region 6
0 is not directly irradiated by the electron beam, and only the first and second gate electrodes 52 and 54 are irradiated by the electron beam. In FIG. 5, illustration of the passivation film is omitted.

Next, a method of calibrating the dimensions of the scanning electron microscope according to the third embodiment will be described with reference to FIG. FIG. 6 is a diagram for explaining a method of calibrating the dimensions of the scanning electron microscope according to the third embodiment.

First, the switching element 50 is placed on a sample stage (not shown) of the scanning electron microscope, and the first electron beam is applied.
It is placed so as to scan over the gate electrode 52 and the second gate electrode 54.

Here, FIG. 6 shows the switching element 50 mounted on the sample stage and the scanning section of the electron beam in an overlapping manner. The scanning section of the electron beam in FIG. 6 is the same as the scanning section of the electron beam in FIG. Then, as shown in FIG. 6, the scanning section of the electron beam crosses over the first gate electrode 52 and the second gate electrode 54 in a stripe shape, respectively. In FIG. 6,
The switching element is placed so that each scanning section vertically crosses each of the stripe-shaped gate electrodes 52 and 54, but the direction in which the gate electrode 52 extends is not necessarily Y.
The directions do not have to match. In FIG. 6, since the first and second gate electrodes 52 and 54 are longer than the Y direction of the observation target region 24, all the scanning sections of the observation target region 24 correspond to the first and second gate electrodes. Although it crosses over the electrodes 52 and 54, only a part of the scanning section of the observation target region 24 may cross over the first and second gate electrodes 52 and 54 in common.

Also, in the third embodiment, as in the case of the above-described first embodiment, the conditions of the accelerating voltage and current of the electron beam are the same as those for measuring the dimensions of the sample to be measured. It is preferably the same as

In the third embodiment, as in the case of the above-described first embodiment, the electric signal output from the switching element 50 is detected. When the first gate electrode 52 of the switching element 50 is irradiated with the electron beam, the potential of the first gate electrode 52 changes.
As a result, the switching element 50 performs a switching operation at a portion corresponding to the first gate electrode 52, and an electric signal between the first source region 56 and the drain region 58 changes. In the switching element 50, the intensity of the first source / drain current between the first source region 56 and the drain region 58 is increased only while the electron beam is irradiating the first gate electrode 52.

Further, when the second gate electrode 54 is irradiated with an electron beam, the potential of the second gate electrode 54 changes.
As a result, the switching element 50 performs a switching operation at a portion corresponding to the second gate electrode 54, and an electric signal between the second source region 60 and the drain region 58 changes. In the switching element 50, the intensity of the second source / drain current between the second source region 60 and the drain region 58 is increased only while the electron beam irradiates the second gate electrode 54.

[0139] Upon scanning of the electron beam, the electron beam begins scanning the first scan section 30 from the first point 26, at time t _1, a first first first gate electrode 52 on the scanning section 30 of The first irradiation position 68 which is the edge near the point 26 is irradiated. Subsequently, the electron beam is emitted at time u.
₁ is irradiated at a second irradiation position 70, which is an edge of the second gate electrode 54 on the first scanning section 30 near the first point 26.

The electron beam that has passed through the second irradiation position 70 scans the remaining section of the first scanning section 30 to reach the second point 28, and then reaches the second point 28.
It moves to the third point 32 which is the starting point of No. 6. Then, the second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
Electron beam begins scanning 6, the time t _2, the irradiation with a third point 32 near the edge of the second first gate electrode 52 on the scanning section 36 of the third irradiation position 72. Subsequently, the electron beam is irradiated at time u ₂ in the second scanning section 36.
A fourth irradiation position 74 which is an edge of the upper second gate electrode 54 near the third point 32 is irradiated.

Then, the electron beam having passed through the fourth irradiation position 74 scans the remaining section of the second scanning section 36 to reach the fourth point 34, and then reaches the start point of the third scanning section. Move on. Hereinafter, the electron beam sequentially irradiates the first and second gate electrodes 52 and 54 for each scanning section, scans the final scanning section, and completes scanning of one screen.

Here, the output of the switching element 50 is shown in the graph of FIG. The horizontal axis of the graph of FIG. 7 represents time (arbitrary unit), and the vertical axis of the graph represents current (arbitrary unit). Also, in the graph of FIG. 7, the first source / drain current shown by the curve I and the second source / drain current shown by the curve II
The waveform of the drain current is a pulse-like waveform. In FIG. 7, for convenience, a curve II is shown above the curve I. This is because the intensity of the second source / drain current shown by the curve II is the first source-drain current shown by the curve I. -It does not indicate that it is stronger than the intensity of the drain current. Actually, the peak intensity of the first source / drain current is substantially equal to the peak intensity of the second source / drain current.

The first peak P ₁ rising at the time t ₁ among the pulse-like peaks of the curve I is the time during which the electron beam scans the first gate electrode 52 in the first scanning section 30. Corresponding to Also, the time t _{2 of the} curve I
The second peak P ₂ rising in the second scanning section 3
6 corresponds to the time when the electron beam scans on the first gate electrode 52.

Also, among the pulse-like peaks of the curve II,
The first peak Q ₁ rising at time u ₁ corresponds to the time during which the electron beam scans over the second gate electrode 54 in the first scanning section 30. Further, the second peak Q ₂ rising at the time u ₂ of the curve II corresponds to the time when the electron beam scans on the second gate electrode 54 in the second scanning section 36.

Further, in the third embodiment, based on the output of the switching element 50, the electron beam scans the first or second gate electrode 52 or 54, and then scans the same gate electrode 52 or 54. In addition to measuring the time until scanning, the electron beam measures the time from scanning the first gate electrode 52 to scanning the second gate electrode 54. Here, the time between the rising times of the peaks is measured.

In the graph of FIG. 7, as an example of the entire scanning time, the time t at which the electron beam irradiates the first irradiation position 68 of the first gate electrode 52 in the first scanning section 30 is shown.
_{In the first} to second scanning sections 36, the first gate electrode 5
2 shows the entire scanning time T up to time t2 when the _second third irradiation position 72 is irradiated. In addition, from the time u ₁ at which the second irradiation position 70 of the second gate electrode 54 is irradiated in the _first scanning section 30 to the time u at which the fourth irradiation position 74 of the second gate electrode 54 is irradiated in the second scanning section 36. Shows the total scan time U up to ₂ . This overall scanning time U is substantially equal to the overall scanning time T.

Further, in the graph of FIG. 7, as an example of the partial scanning time, in the second scanning section 36, the time from the time t ₂ when the electron beam irradiates the third irradiation position 72 to the time when the fourth irradiation position 74 is irradiated by the electron beam. Partial scan time ΔT up to u ₂
Is shown.

As described above, when the partial scanning time between the two control electrodes is measured, not only the variation in the scanning over the entire scanning width of the electron beam but also the scanning time in the partial area between the two control electrodes is obtained. Variation can also be measured. As a result, in one scanning electron microscope, relative dimensional calibration can be performed by adjusting not only the variation in the scanning time in the entire scanning area but also the variation in the scanning time in the partial area to be the same. It can be performed. In addition, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial area is the same between a plurality of scanning electron microscopes. It can be carried out.

In this embodiment, the length a of the short side of the stripe shape of the first gate electrode 52 and the second gate electrode 54, and the distance between the first gate electrode 52 and the second gate electrode 54 Even if c is not exactly known,
It is possible to perform relative dimensional calibration. Further, the dimensions of the first gate electrode 52 and the dimensions of the second gate electrode 54 do not have to be equal.

(Fourth Embodiment) Next, as a fourth embodiment, a method for calibrating the size of a scanning electron microscope according to the third invention and a device for calibrating the size of the scanning electron microscope according to the sixth invention will be described. An example is also described.

FIG. 8 is a configuration diagram for explaining a dimension correcting device for a scanning electron microscope according to the fourth embodiment. The dimension calibrating device 80 includes a first control electrode 82, a second control electrode 84, and a third
A control electrode 86; these three control electrodes 82, 8
A switching element 80 that performs a switching operation when one of 4 and 86 is irradiated with an electron beam. And, again, the first control electrode 8
2. The second control electrode 84 and the third control electrode 86 are spaced apart from each other and arranged in parallel.

This switching element 80 is
MOS formed on i (silicon) semiconductor substrate 14
It has an FET structure. In addition, three control electrodes 8
Reference numerals 2, 84, and 86 are formed by portions exposing the first gate electrode 82, the second gate electrode 84, and the third gate electrode 86 of stripe-shaped polysilicon in the MOS FET structure. The length a of the short side of each of the gate electrodes 82, 84 and 86 in the form of a stripe is about 0.3 μm, and the length b of the long side is about 2 μm.
0 μm. The distance c between the first gate electrode 82 and the second gate electrode 84 and the distance c between the second gate electrode 84 and the third gate electrode 86 are each about 0.5 μm. In FIG. 8, for ease of understanding of the drawing, each of the gate electrodes 82, 84, and 86 is shown with hatching, though not a cross section.

Further, this MOS FET structure has a structure in which the first source region 8
8 and a first drain region 90. Further, a second source region 92 and a first drain region 90 are provided with the second gate electrode 84 interposed therebetween. Further, a second source region 92 and a second drain region 94 are provided with the third gate electrode 86 interposed therebetween.

The region sandwiched between the first gate electrode 82 and the second gate electrode 84 is a common first drain region 90 for the first gate electrode 82 and the second gate electrode 84. Further, the second gate electrode 84 and the third
The region sandwiched between the gate electrode 86 and the second gate electrode 8
The second source region 92 is common to the fourth and third gate electrodes 86.

A bias voltage is applied between the first source region 88 and the second source region 92 and the first drain region 90 and the second drain region 94.
The first source region 88, the first drain region 90, the second source region 92, and the second drain region 94 have a first source terminal 96, a first drain terminal 98, and a second drain terminal 98 for extracting an electric signal. Source side terminal 100 and second
Drain-side terminals 102 are provided.

The region including the first source region 88, the first drain region 90, the second source region 92, and the second drain region 94 is formed by the first gate electrode 82, the second gate electrode 84, and the third gate electrode 84. Except for 86, it is covered with a passivation film. Therefore, the first source region 88, the first drain region 90, the second source region 92, and the second drain region 94 are not directly irradiated by the electron beam, and the first to third gate electrodes 82, 84, and 8 are not irradiated.
Only 6 is irradiated by the electron beam. In FIG. 8, illustration of the passivation film is omitted.

Next, a method for calibrating the dimensions of a scanning electron microscope according to the fourth embodiment will be described with reference to FIG. FIG. 9 is a diagram for explaining a method of calibrating the dimensions of the scanning electron microscope according to the fourth embodiment.

First, the switching element 80 is placed on a sample stage (not shown) of the scanning electron microscope, and the first electron beam is applied.
The gate electrode 82, the second gate electrode 84, and the third gate electrode 86 are placed so as to scan.

FIG. 9 shows the switching element 80 mounted on the sample stage and the scanning section of the electron beam in an overlapping manner. The scanning section of the electron beam in FIG. 9 is the same as the scanning section of the electron beam in FIG. Then, as shown in FIG. 9, the scanning section of the electron beam is composed of a stripe-shaped first gate electrode 82, a second gate electrode 84, and a third gate electrode.
Each crosses over the gate electrode 86.

In FIG. 9, the switching elements are mounted so that each scanning section vertically crosses each of the stripe-shaped gate electrodes 82, 84 and 86. However, each of the gate electrodes 82, 84 and 86 is provided. Does not necessarily coincide with the Y direction. In FIG. 9, the first to third gate electrodes 82, 84, and 86
Because it is longer than the Y direction of the observation target area 24,
Although all scanning sections of the observation target area 24 cross over the first to third gate electrodes 82, 84, and 86, only a part of the scanning section of the observation target area 24 corresponds to the first to third gate electrodes 82, 84, and 86.
The gate electrodes 82, 84 and 86 may be traversed in common.

Also, in the fourth embodiment, as in the case of the above-described first embodiment, the conditions of the acceleration voltage and current of the electron beam are the same as those for measuring the dimensions of the sample to be measured. It is preferably the same as

In the fourth embodiment, as in the case of the first embodiment, an electric signal output from the switching element 80 is detected. When the first gate electrode 82 of the switching element 80 is irradiated with the electron beam, the potential of the first gate electrode 82 changes.
As a result, the switching element 80 performs a switching operation at a portion corresponding to the first gate electrode 82, and an electric signal between the first source region 88 and the first drain region 90 changes. In the switching element 80, the intensity of the first source / drain current between the first source region 88 and the first drain region 90 is increased only while the electron beam is irradiating the first gate electrode 82.

When the second gate electrode 84 is irradiated with an electron beam, the potential of the second gate electrode 84 changes.
As a result, the switching element 80 performs a switching operation at a portion corresponding to the second gate electrode 84, and an electric signal between the second source region 92 and the first drain region 90 changes. In the switching element 80, the intensity of the second source / drain current between the second source region 92 and the first drain region 90 is increased only while the electron beam is irradiating the second gate electrode 84.

When the third gate electrode 86 is irradiated with an electron beam, the potential of the third gate electrode 86 changes.
As a result, the switching element 80 performs a switching operation at a portion corresponding to the third gate electrode 86, and an electric signal between the second source region 92 and the second drain region 94 changes. In the switching element 80, the intensity of the third source / drain current between the second source region 92 and the second drain region 94 increases only while the electron beam is irradiating the third gate electrode 86.

[0166] Upon scanning of the electron beam, the electron beam begins scanning from the first point 26 first scan section 30, at time t _1, first the first gate electrode 82 on the first scanning section 30 The first irradiation position 104, which is the edge near the point 26, is irradiated. Subsequently, the electron beam is applied at time u ₁ to the second gate electrode 84 on the first scanning section 30.
Irradiation position 106, which is the edge near the first point 26 of FIG.
Is irradiated. Subsequently, the electron beam irradiates the third irradiation position 108 at the time v ₁ , which is the edge from the first point 26 of the third gate electrode 86 on the first scanning section 30.

Then, the electron beam that has passed through the third irradiation position 108 scans the remaining section of the first scanning section 30 to reach the second point 28, and then starts at the start point of the second scanning section 36. It moves to the third point 32. And
The second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
Electron beam begins scanning 6, the time t _2, the irradiation with a third point 32 near the edge of the first gate electrode 82 on the second scanning section 36 fourth irradiation position 110. Subsequently, the electron beam is emitted at time u ₂ in the second scanning section 3.
The fifth irradiation position 112, which is the edge of the second gate electrode 84 on 6 near the third point 32, is irradiated. Subsequently, an electron beam, a time v _2, is irradiated a second time sixth irradiation position 114 is a third point 32 near the edge of the third gate electrode 86 on the scanning section 36.

Then, the electron beam having passed through the sixth irradiation position 114 scans the remaining section of the second scanning section 36 to reach the fourth point 34, and then reaches the start point of the third scanning section. Move on. Hereinafter, the electron beam sequentially irradiates the first, second, and third gate electrodes 82, 84, and 86 in each scanning section, scans the final scanning section, and completes scanning of one screen. I do.

Here, the output of the switching element 80 is shown in the graph of FIG. The horizontal axis of the graph in FIG. 10 represents time (arbitrary unit), and the vertical axis of the graph represents current (arbitrary unit).
Represents Further, in the graph of FIG. 10, the first source / drain current indicated by the curve I, the second source / drain current indicated by the curve II, and the third source / drain current indicated by the curve III
The waveform of the drain current is a pulse-like waveform.

In FIG. 10, for convenience, the curve I
The curve II is shown above the curve II, and the curve III is shown above the curve II. This is because the intensity of the second source-drain current shown by the curve II is higher than that of the first source-drain current shown by the curve I. It does not indicate that the intensity of the third source / drain current indicated by the curve III is higher than the intensity of the second source / drain current indicated by the curve II. . In fact, the first
The peak intensity of the source / drain current, the peak intensity of the second source / drain current, and the peak intensity of the third source / drain current are all the same.

The first peak P ₁ rising at the time t ₁ among the pulse-like peaks of the curve I is the time during which the electron beam scans the first gate electrode 82 in the first scanning section 30. Corresponding to Also, the time t _{2 of the} curve I
The second peak P ₂ rising in the second scanning section 3
6 corresponds to the time when the electron beam is scanning over the first gate electrode 82.

Further, among the pulse-like peaks of the curve II,
The first peak Q ₁ rising at time u ₁ corresponds to the time during which the electron beam scans over the second gate electrode 84 in the first scanning section 30. The second peak Q ₂ rising at the time u ₂ of the curve II corresponds to the time during which the electron beam scans the second gate electrode 84 in the second scanning section 36.

The first peak R ₁ rising at the time v ₁ among the pulse-like peaks of the curve III is the time during which the electron beam scans the third gate electrode 86 in the first scanning section 30. Corresponding to The time v of the curve III
_{The second} peak R ₂ rising to 2 corresponds to the time when the electron beam scans on the third gate electrode 86 in the second scanning section 36.

Further, in the fourth embodiment, the electron beam scans the first gate electrode 82, the second gate electrode 84, or the third gate electrode 86 based on the output of the switching element 80, and then scans the electron beam. Same gate electrodes 82, 8
In addition to measuring the entire scanning time until scanning 4 or 86, the first scanning time required for the electron beam to scan the first gate electrode 82 and then scan the second gate electrode 84.
The partial scanning time and the electron beam are applied to the second gate electrode 8
The second partial scanning time required from scanning 4 to scanning the third gate electrode 86 is measured. Here, the time between the rising times of the peaks is measured.

In the graph of FIG. 10, as an example of the entire scanning time, the electron beam is irradiated on the first irradiation position 104 of the first gate electrode 82 in the first scanning section 30 from the time t _{1 in the} second scanning section. in 36 shows the scanning time T until time t ₂ when irradiated with the fourth irradiation position 110 of the first gate electrode 82. Further, as an example of the first partial scanning time, in the graph of FIG. 10, in the second scanning section 36, the time u from the time t ₂ at which the electron beam irradiates the fourth irradiation position 110 to the time u at which the fifth irradiation position 112 is irradiated. The partial scan time ΔT ₁ up to ₂ is shown. Further, as an example of the second partial scanning time, in the second scanning section 36, the electron beam irradiates the fifth irradiation position 112 from the time u ₂ to the sixth irradiation period.
The partial scan time ΔT ₂ up to time v ₂ when the irradiation position 114 is irradiated is shown.

As described above, by measuring the first partial scanning time and the second partial scanning time as the partial scanning time in each scanning section, not only the variation in scanning over the entire scanning width of the electron beam, but also Variations in partial scan time between a plurality of different partial regions between two control electrodes can also be measured. As a result, in one scanning electron microscope, relative dimensional calibration can be performed by adjusting not only the variation in the scanning time in the entire scanning area but also the variation in the scanning time in the partial area to be the same. It can be performed. In addition, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial area is the same between a plurality of scanning electron microscopes. It can be carried out.

In this embodiment, the respective stripe-shaped dimensions of the first gate electrode 82, the second gate electrode 84, and the third gate electrode 86, and the size of the first gate electrode 82 and the second gate electrode 84 are different. Even if the interval and the interval between the second gate electrode 84 and the third gate electrode 86 are not accurately known, the dimensional calibration can be performed relatively. Also, the dimensions of each gate electrode need not be equal to each other. Further, the first gate electrode 82 and the second gate electrode 84
, The second gate electrode 84 and the third gate electrode 86
May not be equal.

(Fifth Embodiment) Next, as a fifth embodiment, an example of a method for calibrating dimensions of a scanning electron microscope according to the third invention will be described. In the fifth embodiment, the dimensional calibration device used in the above-described fourth embodiment is used.

In the fifth embodiment, first, FIG.
The second gate electrode 84 which is a gate electrode other than the outermost one of the gate electrodes shown in FIG. Then, the switching element 80 is mounted on the sample table so that the reference control electrode 84 comes to a position where the reference control electrode 84 is irradiated with the electron beam when not being deflected by the scanning electron microscope.

When scanning of the electron beam by the scanning electron microscope is started, the electron beam is deflected, and the reference control electrode 84 is deflected.
Swings left and right around the center. Then, the reference control electrode 84
Is irradiated around the gate electrode.

In the fifth embodiment, the first gate electrode 82 and the third gate electrode 86 are provided on both sides of the second gate electrode 84 as the reference control electrode 84. The first distance between the first gate electrode 82 and the second gate electrode 84 is equal to the second distance between the second gate electrode 84 and the third gate electrode 86. Therefore, the first gate electrode 82 and the third gate electrode 86 are arranged at symmetrical positions with the second gate electrode 84 interposed therebetween.

In this embodiment, the scanning time at the first interval and the scanning time at the second interval are measured for two control electrodes arranged symmetrically with the reference control electrode 84 interposed therebetween. .

If the electron beam is not deviated left and right,
The scanning time of the first interval is equal to the scanning time of the second interval. Further, when there is a bias, the scanning time at the first interval is not equal to the scanning time at the second interval. further,
When the electron beam has a large bias, the electron beam may irradiate only one of the first gate electrode 82 and the third gate electrode 86 in some cases.

As described above, the scanning time of the first interval and the scanning time of the second interval, which are the scanning times of the two control electrodes symmetrical with respect to the reference control electrode, are measured and compared. In addition, it is possible to detect the deviation of the electron beam of the electron microscope.

(Sixth Embodiment) Hereinafter, an electron beam detection method according to a seventh invention, an electron beam detection method for a scanning electron microscope according to an eighth invention, and a scanning electron according to a ninth invention according to this application will be described. An example of a method for calibrating the dimensions of a microscope, an electron beam detecting apparatus according to an eleventh aspect of the present invention, and an example of a dimension calibrating apparatus for a scanning electron microscope according to a twelfth aspect will be described together with a sixth embodiment.

FIG. 11 is a block diagram for explaining a dimension correcting apparatus for a scanning electron microscope according to the sixth embodiment.
In addition, this dimension correction device includes an electron beam detection device.

[0188] The dimension calibrating device 120 converts the superconductor 126 having a stripe shape as viewed from above from a silicon (S)
i) Peltier cooling element 12 installed on substrate 122
4 above. Length a of the short side of this stripe shape
Is about 0.2 μm, and the length b of the long side is about 20 μm
It is. In addition, the first terminal 128 and the second terminal
A terminal 130 is provided. In FIG. 11, the superconductor 126 is hatched, though not a cross section, to facilitate understanding of the drawing. The Peltier cooling element 124 is covered with a passivation film.
In FIG. 1, illustration of the passivation film is omitted.

The superconductor 126 is made of an oxide superconductor having a thickness of about 500 ° formed by MBE (Molecular Beam Epitaxy), and has a composition of Ba ₂ Y ₁ Cu.
₃ O ₇ . The superconductor 126 is cooled by the Peltier cooling element 124 so as to maintain the superconducting state.

Next, a method for calibrating the dimensions of a scanning electron microscope according to the sixth embodiment will be described with reference to FIG. Note that this dimension calibration method includes a method of detecting an electron beam, and also includes a method of detecting an electron beam of a scanning electron microscope. FIG. 12 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the sixth embodiment;
The dimension calibration device 120 mounted on the sample stage and the scanning section of the electron beam are shown in an overlapping manner. FIG.
Are the same as the electron beam scanning section in FIG.

In the dimensional calibration, first, the superconductor 1
The dimensional calibration device 120 having 26 is mounted on a sample stage (not shown) of the scanning electron microscope so that the electron beam scans over the superconductor 126.

As shown in FIG. 12, each scanning section of the electron beam crosses over the stripe-shaped superconductor 126. In FIG. 12, the dimensional calibration device is placed so that each scanning section crosses the stripe-shaped superconductor 126 vertically.
The extending direction of 26 does not necessarily have to coincide with the Y direction. Further, in FIG. 12, since the superconductor 126 is longer than the Y direction of the observation target region 24, all the scanning sections of the observation target region 24 cross the superconductor 126. Only a portion of the scan zone of region 24 may cross over superconductor 126.

In the sixth embodiment, the electrical resistance between the first terminal 128 and the second terminal 130 at both ends of the superconductor 126 is detected as the output of the dimension calibration device 120. When the superconductor 126 is irradiated with the electron beam, the superconducting state is broken, and the electric resistance between the first terminal 128 and the second terminal 130 increases. Further, in the dimension correcting device 120, the electric resistance between the first terminal 128 and the second terminal 130 increases only while the superconductor 126 is irradiated with the electron beam. That is, by irradiating the superconductor 126 of the dimension calibration device 120 with the electron beam, the first terminal 128 of the dimension calibration device 120 is irradiated.
And an electric signal output from the second terminal 130,
An electron beam can be detected. Further, the conditions of the acceleration voltage and the current of the electron beam are preferably the same as the conditions for measuring the dimensions of the sample to be measured.

At the time of electron beam scanning, the electron beam that has started scanning in the first scanning section 30 from the first point 26 is moved to the first point of the superconductor 126 on the first scanning section 30 at time t _1. The first irradiation position 132, which is the edge closer to 26, is irradiated. Then, the electron beam that has passed through the first irradiation position 132 scans the remaining section of the first scanning section 30 and scans the second point 2 which is the end point of the first scanning section.
Then, the process moves to the third point 32, which is the start point of the second scanning section 36. Then, the second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
The electron beam that has started the scanning of the sixth superconductor 126 at the time t ₂ is the third point 32 of the superconductor 126 on the second scanning section 36.
The second irradiation position 134 which is a closer edge is irradiated. Then, the electron beam that has passed through the second irradiation position 134 scans the remaining section of the second scanning section 36 and reaches the fourth point 34 which is the end point of the second scanning section 36. Move to the start point of the second scanning section. Thereafter, the electron beam irradiates the superconductor 126 for each scanning section, scans the last scanning section, and ends scanning of one screen.

Next, the graph of FIG.
20 shows the output. The horizontal axis of the graph in FIG. 13 represents time (arbitrary unit), and the vertical axis of the graph represents electric resistance (arbitrary unit). Dimension calibration device 1 used in the sixth embodiment
In 20, the electric resistance between the first terminal 128 and the second terminal 130 increases only while the electron beam is irradiating the superconductor 126. Therefore, the output waveform of the dimension calibration device 120 becomes a pulse-shaped waveform as shown by the curve IV in the graph of FIG.

The first peak A ₁ among the pulse-like peaks of the curve IV in the graph of FIG. 13 corresponds to the time when the electron beam scans the superconductor 126 in the first scanning section 30. Correspondingly, the second peak A ₂ corresponds to the time during which the electron beam is scanning over the superconductor 126 in the second scanning section 36.

Further, in the sixth embodiment, based on the output of the dimension calibrating device 120, the time from when the electron beam scans the superconductor 126 to when the superconductor 126 is next scanned again is determined. Is measured. Here, the time between the rising times of the peaks is measured.

In the graph of FIG. 13, as an example of the whole scanning time, the time t ₁ at which the electron beam irradiates the first irradiation position 132 of the superconductor 126 in the first scanning section 30.
Second in scanning section 36 until the time t ₂ being irradiated with the second irradiation position 134 of the superconductors 126 scan time from T
Is shown.

Then, in addition to the scanning time T over the first scanning section 30 and the second scanning section 36, scanning over other mutually continuous scanning sections (for example, the second scanning section and the third scanning section). Measure the time respectively. As a result, variation in each scanning time can be known. By adjusting the electron microscope so that the variation in each scanning time is minimized, relative dimensional calibration can be performed.

Further, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the relative dimensions of the scanning electron microscope. Can be. As a result, it is possible to reduce variations in measurement dimensions due to differences in the used machines when a plurality of scanning electron microscopes are used.

In the present embodiment, even if the dimensions of the stripe shape of superconductor 126 are not accurately known, the dimensions can be calibrated relatively.

In the sixth embodiment, since the dimension correction is performed directly by detecting the electron beam, there is no need to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

In the sixth embodiment, since it is not necessary to use the SEM image of the reference sample, the SEM
And is not affected by variations in the performance of secondary electron detectors and CRTs that display images. For this reason, in dimensional calibration,
Variation in dimensional calibration between SEMs can be reduced.

The superconducting state of the superconductor is usually broken by a slight irradiation of an electron beam. Therefore, in the sixth embodiment, it is possible to detect even an electron beam having a lower intensity. As the electron beam is weaker, the size of the spot of the electron beam becomes smaller, so that the electron beam can be detected with higher accuracy. As a result, the accuracy of dimensional calibration can be improved.

(Seventh Embodiment) In the seventh embodiment, an example of the dimension calibration method for a scanning electron microscope according to the tenth invention and an example of the dimension calibration apparatus for the electron microscope according to the twelfth invention will be described. explain.

In the dimension correcting apparatus 120 according to the sixth embodiment, if the dimensions of the stripe-shaped superconductor 126 are accurately determined, absolute dimension calibration can be performed. For example, when the length a of the short side of the superconductor 126 of the dimension calibration device 120 is known to be exactly 0.2 μm,
If the dimensional calibration device 120 is mounted on the sample table so that the electron beam scanning section crosses the superconductor 126 vertically, the length of the scanning section on the superconductor 126 is determined to be 0.2 μm.

Thus, by measuring the time τ during which the electron beam scans over the superconductor 126, the absolute scanning speed of the electron beam in the scanning section can be obtained. In the graph of FIG. 13, the time τ during which the electric resistance having the pulse-shaped waveform flows corresponds to the time during which the electron beam scans the superconductor 126.

[0209] Therefore, based on the absolute scanning speed of the electron beam, it is possible to perform dimension calibration in dimension measurement by a scanning electron microscope. Also, by adjusting the electron microscope to make the absolute scanning speed of the electron beam constant, it is possible to reduce the variation in dimension measurement in the same machine and the variation in dimension measurement in multiple machines. Can be planned.

(Eighth Embodiment) Next, as an eighth embodiment, a dimensional calibration method for a scanning electron microscope according to a ninth invention and a dimensional calibration apparatus for a scanning electron microscope according to a twelfth invention will be described. An example is also described.

FIG. 14 is a block diagram for explaining a dimension correcting device for a scanning electron microscope according to the eighth embodiment. The dimensional calibration device 136 includes a Peltier cooling element mounted on a silicon (Si) substrate 122 by using a first superconductor 138 and a second superconductor 140 whose superconducting state is broken when irradiated with an electron beam. On the reference numeral 124, they are arranged separately from each other. These two superconductors 138 and 140 have stripe shapes when viewed from above. The length a of the short side of each of these stripe shapes is about 0.2 μm, and the length b of the long side is about 20 μm. The distance c between the first superconductor 138 and the second superconductor 140 is about 0.5
μm. Further, a first terminal 142 and a second terminal 144 are provided at both ends of the first superconductor 138 in the long side direction of the sprite shape. Further, a third terminal 146 and a fourth terminal 148 are provided at both ends of the sprite shape of the second superconductor 140 in the long side direction.

In FIG. 14, the first superconductor 138 and the second superconductor 140 are shown for easy understanding of the drawings.
Are not shown in cross-section, but are indicated by hatching. Further, the Peltier cooling element 124 is covered with a passivation film, but the illustration of the passivation film is omitted in FIG.

Each of the first superconductor 138 and the second superconductor 140 is made of an oxide superconductor having a thickness of about 500 ° formed by MBE (Molecular Beam Epitaxy), and has a composition of Ba. ₂ Y ₁ Cu ₃ O ₇ . The first superconductor 138 and the second superconductor 140 are cooled by the Peltier cooling element 124 to maintain the superconducting state.

Next, a method for calibrating the dimensions of a scanning electron microscope according to the eighth embodiment will be described with reference to FIG. FIG. 15 is a diagram for explaining a method of calibrating the dimensions of the scanning electron microscope according to the eighth embodiment.

First, the dimensional calibration device 136 is mounted on a sample stage (not shown) of the scanning electron microscope so that the electron beam scans over the first superconductor 138 and the second superconductor 140. I do.

Here, FIG. 15 shows a dimension calibration device 136 mounted on the sample table and a scanning section of the electron beam in an overlapping manner. The scanning section of the electron beam in FIG.
This is the same as the scanning section of the electron beam in FIG. Then, as shown in FIG. 15, the scanning section of the electron beam traverses over the first superconductor 138 and the second superconductor 140 in a stripe shape. In FIG. 15, each scanning section corresponds to each stripe-shaped superconductor 138.
And 140 are traversed vertically.
6 are placed, but the extending direction of the superconductor 136 does not necessarily have to coincide with the Y direction. FIG.
, The first and second superconductors 138 and 14
Since 0 is longer than the Y direction of the observation target region 24, all scan sections of the observation target region 24 cross over the first and second superconductors 138 and 140,
Only a part of the scanning section of the observation target area 24 is the first
And on the second superconductors 138 and 140 in common.

Also, in the eighth embodiment, as in the case of the above-described sixth embodiment, the conditions of the acceleration voltage and the electric resistance of the electron beam are changed when the dimensions of the sample to be measured are measured. Preferably, the conditions are the same.

In the eighth embodiment, as in the case of the above-described sixth embodiment, an electric signal output from the dimension calibration device 136 is detected. In the eighth embodiment, the first electric resistance between the first terminal 142 and the second terminal 144 at both ends of the first superconductor 138 and the second superconductor 14
The second electrical resistance between the third terminal 146 and the fourth terminal 148 at both ends of the zero is detected.

When the first superconductor 138 is irradiated with an electron beam, the superconducting state is broken, and the first terminal 142 and the second terminal
The first electrical resistance between the terminal 144 and the terminal 144 increases. Then, in the dimension correction device 136, the first electric resistance increases only while the first superconductor 138 is irradiated with the electron beam. When the second superconductor 140 is irradiated with an electron beam, the superconducting state is broken, and the second electric resistance between the third terminal 146 and the fourth terminal 148 increases. Then, in the dimension correction device 136, the second electric resistance increases only while the second superconductor 140 is irradiated with the electron beam.

At the time of electron beam scanning, the electron beam that has started scanning in the first scanning section 30 from the first point 26 is moved to the first superconductor 138 on the first scanning section 30 at time t ₁ . The first irradiation position 150 which is an edge near one point 26 is irradiated. Subsequently, the electron beam is applied to the second superconductor 140 on the first scanning section 30 at time u _1.
Irradiation position 152, which is an edge near the first point 26 of FIG.
Pass through. Then, the electron beam that has passed through the second irradiation position 152 scans the remaining section of the first scanning section 30 to reach the second point 28 which is the end point of the first scanning section, and then performs the second scanning. It moves to the third point 32 which is the starting point of the ward 36. Then, the second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
The electron beam that has started the scanning of No. 6 irradiates the third irradiation position 154 which is the edge of the first superconductor 138 on the second scanning section 36 near the third point 32 at the time t ₂ . Subsequently, the electron beam is emitted at time u ₂ in the second scanning section 3.
6 passes through a fourth irradiation position 156 which is an edge of the second superconductor 140 near the third point 32. Then, the electron beam that has passed through the fourth irradiation position 156 scans the remaining section of the second scanning section 36 to perform the second scanning section 36.
Reaches the fourth point 34, which is the end point, and then moves to the start point of the third scanning section. Hereinafter, the electron beam irradiates the first superconductor 138 and the second superconductor 140 in each scanning section, scans the final scanning section, and ends scanning of one screen.

Here, the output of the dimensional calibration device 136 is shown in the graph of FIG. The horizontal axis of the graph in FIG. 16 represents time (arbitrary unit), and the vertical axis of the graph represents electric resistance (arbitrary unit).
Represents In addition, the waveforms of the first electric resistance indicated by the curve IV and the second electric resistance indicated by the curve V in the graph of FIG. 16 are pulse-shaped waveforms.

In FIG. 16, for convenience, the curve IV
Above, the curve V does not indicate that the second electric resistance indicated by the curve V is higher than the first electric resistance indicated by the curve IV. Actually, the magnitude of the peak of the first electric resistance and the magnitude of the peak of the second electric resistance are substantially the same.

In the pulse-like peak of the curve IV in the graph of FIG. 16, the first peak A ₁ is that the electron beam scans the first superconductor 138 in the first scanning section 30. The second peak A ₂ corresponds to the time when the electron beam is scanning over the first superconductor 138 in the second scanning section 36. Further, among the pulse-like peaks of the curve V, the first peak B ₁ corresponds to the first scanning section 30.
Corresponds to the time during which the electron beam scans on the second superconductor 140, and the second peak B ₂ corresponds to the second scanning section 3
6 corresponds to the time when the electron beam is scanning over the second superconductor 140.

Further, in the eighth embodiment, based on the output of the dimensional calibration device 136, the electron beam
Alternatively, the electron beam scans the first superconductor 138 as well as measures the total scan time from scanning the second superconductor 138 or 140 to the next scan of the same superconductor 138 or 140. After that, the partial scanning time from when the second superconductor 140 is scanned is measured in each scanning section. Here, the time between the rising times of the peaks is measured.

In the graph of FIG. 16, the rising time t ₁ of the first peak A ₁ of the curve IV is shown as an example of the entire scanning time.
Difference T between the time and the rising time t _{2 of} the second peak A ₂
Is shown. Also shows the time difference U between the time u ₂ rising rise time u ₁ of the first peak of the B ₁ curve V and the second peak B _2. The entire scanning time U is substantially equal to the entire scanning time T.

Further, in the graph of FIG. 16, as an example of the partial scanning time, the curve in the second scanning section 36 is used.
The time difference ΔT between the rising time t ₂ of the second peak A ₂ of IV and the rising time u ₂ of the second peak B ₂ of the curve V is shown.

As described above, when the scanning time between the two control electrodes is measured, not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the two control electrodes is obtained. Can also be measured. as a result,
Performing relative dimensional calibration by adjusting not only the variation in the scanning time of the entire scanning area but also the variation in the scanning time in the partial area in one scanning electron microscope Can be. In addition, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial area is the same between a plurality of scanning electron microscopes. It can be carried out.

In this embodiment, the size of each stripe of first superconductor 138 and second superconductor 140 and the distance between first superconductor 138 and second superconductor 140 are different from each other. Even if they are not precisely known, dimensional calibration can be performed relatively.

(Ninth Embodiment) Next, as a ninth embodiment, a dimensional calibration method for a scanning electron microscope according to a ninth invention and a dimensional calibration apparatus for a scanning electron microscope according to a twelfth invention will be described. An example is also described.

FIG. 17 is a configuration diagram for explaining a dimensional calibration device for a scanning electron microscope according to the ninth embodiment. This dimension correction device 160 is configured to convert the first superconductor 162, the second superconductor 164, and the third superconductor 166 into silicon (Si) when the superconducting state is broken when the electron beam is irradiated.
On a Peltier cooling element 124 installed on the substrate 122 of FIG. Then, these three superconductors 162, 164 and 16
6 each have a stripe shape when viewed from above. The length a of the short side of each of these stripe shapes is about 0.2 μm, and the length b of the long side is about 2 μm.
0 μm. The distance c between the first superconductor 162 and the second superconductor 164 and the distance c between the second superconductor 164 and the third superconductor are both about 0.5 μm. Further, the first terminal 168 and the second terminal 1 are provided at both ends of the first superconductor 162 in the long side direction of the stripe shape, respectively.
70 is provided. Further, the third terminal 1 is provided at each end of the second superconductor 164 in the long side direction of the stripe shape.
72 and a fourth terminal 174 are provided. Further, a fifth terminal 176 and a sixth terminal 178 are provided at both ends of the third superconductor 166 in the long side direction of the stripe shape.

In FIG. 17, the first superconductor 162, the second superconductor 164, and the third superconductor 166 are hatched, though not in cross section, to facilitate understanding of the drawing. Shown. Also, the Peltier cooling element 124
Are covered with a passivation film, but the illustration of the passivation film is omitted in FIG.

The superconductors 162, 164
And 166 are both MBE (Molecular Beam Epitaxy)
It is made of an oxide superconductor having a thickness of about 500 ° formed by the method, and its composition is Ba ₂ Y ₁ Cu ₃ O ₇ .
And the respective superconductors 162, 164 and 166
Is cooled by the Peltier cooling element 124 to maintain the superconducting state.

Next, a method of calibrating the dimensions of the scanning electron microscope according to the ninth embodiment will be described with reference to FIG. FIG. 18 is a diagram for explaining a method of calibrating the dimensions of the scanning electron microscope in the ninth embodiment.

First, the dimensional calibration device 160 is set on a sample stage (not shown) of the scanning electron microscope, and the electron beam is applied to the first superconductor 162, the second superconductor 164, and the third superconductor 166. Is mounted so as to scan.

Here, FIG. 18 shows a dimension calibration device 160 placed on the sample table and a scanning section of the electron beam in an overlapping manner. The scanning interval of the electron beam in FIG.
This is the same as the scanning section of the electron beam in FIG. Then, as shown in FIG. 18, the scanning section of the electron beam is composed of a first superconductor 162 and a second superconductor 16 in a stripe shape.
Fourth and third superconductors 166, respectively. In FIG. 18, the dimension calibration device 160 is placed so that each scanning section vertically crosses each of the stripe-shaped superconductors 162, 164, and 166.
The extending direction of each superconductor 162, 164 and 166 is
It does not necessarily have to coincide with the Y direction. FIG.
8, the first, second and third superconductors 162,
Since 164 and 166 are longer than the Y direction of the observation region 24, all scanning sections of the observation region 24 cross over the superconductors 162, 164 and 166, but the observation region 24 Of the superconductors 162, 164, and 166 may be commonly traversed.

Also, in the ninth embodiment, as in the case of the above-described sixth embodiment, the conditions of the acceleration voltage and the electric resistance of the electron beam are changed when the dimensions of the sample to be measured are measured. Preferably, the conditions are the same.

In the ninth embodiment, as in the case of the above-described sixth embodiment, an electric signal output from the dimension calibration device 160 is detected. In the ninth embodiment, a first electric resistance between the first terminal 168 and the second terminal 170 at both ends of the first superconductor 162 and an electric signal of the second superconductor 164 are provided as electric signals. The second electric resistance between the third terminal 172 and the fourth terminal 174 at both ends and the fifth terminal 17 at both ends of the third superconductor 166
A third electrical resistance between each of the sixth and sixth terminals 178 is detected.

When the first superconductor 162 is irradiated with an electron beam, the superconducting state of the first superconductor 162 is broken,
The first electric resistance between the first terminal 168 and the second terminal 170 increases. Then, in the dimension calibration device 160, the first electric resistance increases only while the first superconductor 162 is irradiated with the electron beam. When the second superconductor 164 is irradiated with the electron beam, the superconducting state of the second superconductor 164 is broken, and the third terminal 172 and the fourth
The second electric resistance between the terminal 174 and the terminal 174 increases. Then, in the dimension correcting device 160, the second electric resistance increases only while the second superconductor 164 is irradiated with the electron beam. When the third superconductor 166 is irradiated with an electron beam, the superconducting state of the third superconductor 166 is broken, and the third electric resistance between the fifth terminal 176 and the sixth terminal 178 is reduced. growing. Then, in the dimension correcting device 160, the third electric resistance increases only while the third superconductor 166 is irradiated with the electron beam.

At the time of scanning of the electron beam, the electron beam which has started scanning in the first scanning section 30 from the first point 26 is moved to the first superconductor 162 on the first scanning section 30 at time t ₁ . The first irradiation position 180 which is an edge near one point 26 is irradiated. Subsequently, the electron beam is applied at time u ₁ to the second superconductor 164 on the first scanning section 30.
Irradiation position 182 which is the edge near the first point 26 of FIG.
Pass through. Subsequently, an electron beam, a time v _1, passes through the third irradiation position 184 which is a third edge of the first point 26 side of the superconductor 166 on the first scan section 30.

Then, the electron beam having passed through the third irradiation position 184 scans the remaining section of the first scanning section 30 to reach the second point 28 which is the end point of the first scanning section. The process moves to the third point 32, which is the start point of the second scanning section 36. Then, the second scanning of the scanning section 36 from the third point 32 is started.

The second scanning section 3 from the third point 32
The electron beam that has started the scanning of No. 6 irradiates the fourth irradiation position 186 at time t ₂ , which is the edge of the first superconductor 162 on the second scanning section 36 near the third point 32. Subsequently, the electron beam is emitted at time u ₂ in the second scanning section 3.
6 passes through a fifth irradiation position 188 which is an edge of the second superconductor 164 on the sixth point near the third point 32. Subsequently, an electron beam, a time v _2, passes through the sixth irradiation position 190 is a third third point 32 near the edge of the superconductor 166 on the second scanning section 36.

Then, the electron beam that has passed through the sixth irradiation position 190 scans the remaining section of the second scanning section 36 and reaches the fourth point 34 which is the end point of the second scanning section 36. Then, the process moves to the start point of the third scanning section.
Hereinafter, the electron beam is applied to the first superconductor 162, the second superconductor 164, and the third superconductor 16 in each scanning section.
6 is sequentially irradiated to scan the last scanning section to complete scanning of one screen.

Here, the output of the dimensional calibration device 160 is shown in the graph of FIG. The horizontal axis of the graph in FIG. 19 represents time (arbitrary unit), and the vertical axis of the graph represents electric resistance (arbitrary unit).
Represents In the graph of FIG. 19, the first electric resistance indicated by the curve IV, the second electric resistance indicated by the curve V, and the curve
The waveform of the third electric resistance indicated by VI is a pulse-like waveform.

In FIG. 19, for convenience, the curve IV
Shows a curve V above the curve V and a curve VI above the curve V, which indicates that the second electric resistance shown by the curve V is larger than the first electric resistance shown by the curve IV. And the third electrical resistance shown by curve VI is
It does not indicate that the electric resistance is larger than the second electric resistance indicated by the curve V. Actually, the magnitude of the peak of the first electrical resistance, the magnitude of the peak of the second electrical resistance, and the magnitude of the peak of the third electrical resistance are substantially equal to each other.

In the pulse-like peak of the curve IV in the graph of FIG. 19, the first peak A ₁ is that the electron beam scans the first superconductor 162 in the first scanning section 30. corresponds to a time, the second peak a ₂ is an electron beam in the second scanning section 36 corresponds to the time during which scanning the first superconductor 162. Further, among the pulse-like peaks of the curve V, the first peak B ₁ is the first scanning section 3
Zero corresponds to the time when the electron beam is scanning over the second superconductor 164, and the second peak B ₂ is that the electron beam scans over the second superconductor 164 in the second scanning section 36. Corresponding to the time you are. Further, among the pulse-like peaks of the curve VI, the first peak C ₁ corresponds to the time when the electron beam scans on the third superconductor 166 in the first scanning section 30, and The peak C ₂ corresponds to the time when the electron beam scans on the third superconductor 166 in the second scanning section 36.

Further, in the ninth embodiment, based on the output of the dimension calibration device 160, the electron beam
The superconductor 162, the second superconductor 164, or the third superconductor 166 is scanned, and then the same superconductor 162, 16
In addition to measuring the total scan time before scanning 4 or 166, the first partial scan time from when the electron beam scans the first superconductor 162 until it scans the second superconductor 164, And the electron beam is applied to the second superconductor 164.
Are measured until the third superconductor 166 is scanned. Here, the time between the rising times of the peaks is measured in each scanning section.

In the graph of FIG. 19, as an example of the entire scanning time, the rising time t ₁ of the first peak A ₁ of the curve IV is shown.
And the time difference T between the second peak A _{2 and} the rising time t ₂ .

Further, in the graph of FIG. 19, as an example of the first partial scanning time, the rising time t ₂ of the second peak A ₂ of the curve IV and the second peak B of the curve V in the second scanning section 36 are shown. the time difference ΔT ₁ and ₂ of the rising time u ₂
Is shown. As an example of the second part scan time, in a second scanning section 36, the second peak c ₂ of the second rise time of the peak B ₂ u ₂ and curve VI curve V rising time v ₂ and the The time difference ΔT ₂ is shown.

As described above, when the three stripe-shaped superconductors are provided and the partial scanning time in each partial scanning section is measured, not only the variation in the scanning over the entire scanning width of the electron beam but also the mutual scanning is obtained. Variations in scanning time between a plurality of different partial regions can also be measured. As a result, in one scanning electron microscope, not only the variation in the scanning time of the entire scanning region but also the variation in the scanning time between a plurality of partial regions is adjusted to be substantially the same, so that relative scanning is performed. Dimensional calibration can be performed. In addition, by adjusting each scanning electron microscope so that the degree of variation in the entire scanning time and the degree of variation in the scanning time in the partial area are the same between a plurality of scanning electron microscopes, the scanning electron microscope Relative dimensional calibration can be performed.

In this embodiment, the first superconductor 162, the second superconductor 164, and the third superconductor 1
66, the distance between the first superconductor 162 and the second superconductor 164, and the distance between the second superconductor 164 and the third superconductor 166 are not precisely known. In both cases, dimensional calibration can be performed relatively.

(Tenth Embodiment) Next, as a tenth embodiment, a dimensional calibration method for a scanning electron microscope according to the ninth invention will be described. In the tenth embodiment, the dimension calibration device used in the ninth embodiment is used.

In the tenth embodiment, first, a second superconductor 164 which is a superconductor other than the outermost one of the superconductors in each stripe shape shown in FIG. Body 164. And this reference superconductor 1
The dimensional calibration device 160 is mounted on the sample table so that the position 64 is irradiated by the electron beam when not receiving the deflection of the scanning electron microscope.

When the scanning of the electron beam by the scanning electron microscope is started, the electron beam is deflected, and the reference superconductor 16 is deflected.
Touch right and left around 4. And the reference superconductor 1
Irradiate the superconductor around 64.

In the tenth embodiment, the first superconductor 164 as the reference superconductor 164 has the first superconductor 164 on both sides.
A superconductor 162 and a second superconductor 166 are provided. A first gap between the first superconductor 162 and the second superconductor 164, and a second superconductor 164 and a third superconductor 166;
Are equal to each other. Therefore, the first
The superconductor 162 and the third superconductor 166 are arranged at symmetrical positions with the second superconductor 164 interposed therebetween.

In this embodiment, the two superconductors arranged at positions symmetrical with respect to the reference superconductor 164 are arranged.
The scan time at the first interval and the scan time at the second interval are measured for one superconductor.

If the electron beam is not deviated in the left-right direction,
The scanning time of the first interval is equal to the scanning time of the second interval. Further, when there is a bias, the scanning time at the first interval is not equal to the scanning time at the second interval. further,
When the electron beam has a large bias, the electron beam may irradiate only one of the first superconductor 162 and the third superconductor 166 in some cases.

As described above, the bias of the electron beam of the scanning electron microscope can be detected by measuring the scanning time at the first interval and the scanning time at the second interval and comparing them with each other.

In each of the embodiments described above, only examples in which these inventions are configured using specific materials and under specific conditions have been described. However, these inventions can be subjected to many changes and modifications. For example, in the embodiment described above, the first
As an example of the electron beam detection method of the seventh invention and the electron beam detection device of the fifth and eleventh inventions, an example of detecting an electron beam of an electron microscope has been described. The seventh and eleventh inventions are, for example,
It can also be used for detecting an electron beam in an electron beam (EB) exposure apparatus.

In the third and fourth embodiments described above, the drain region and the source region corresponding to the two gate electrodes are provided in common. However, in these inventions, each gate electrode is provided for every one gate electrode. Alternatively, a drain region and a source region may be separately provided.

[0261]

【The invention's effect】

(First invention) According to the electron beam detection method of the first invention, by irradiating the control electrode of the switching element with the electron beam, the electron beam can be detected as an electric signal output from the switching element. it can.

(Second Invention) According to the electron beam detection method of the scanning electron microscope of the second invention, the control electrode of the switching element mounted on the sample stage of the scanning electron microscope is irradiated with the electron beam. By doing so, an electron beam can be detected as an electric signal output from the switching element.

In the electron beam detecting method for a scanning electron microscope according to the second invention, the switching element may be
Using a switching element having a MOS FET structure,
If a portion where the gate electrode of the MOS FET structure is exposed is used as the control electrode, the MOS F
By detecting a current between the source region and the drain region of the ET structure, an electron beam can be detected.

(Third invention) According to the method for calibrating dimensions of a scanning electron microscope according to the third invention, an electron beam is applied to a control electrode of a switching element mounted on a sample stage of the scanning electron microscope. Thereby, an electron beam is detected as an electric signal output from the switching element, and further, from this electric signal, a time from when the electron beam scans the control electrode to when the next control electrode is scanned (hereinafter, referred to as “the time”).
Scan time). As a result, it is possible to measure the scanning time, which is the time required for the electron beam to scan in one scan for each scan of the electron beam. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

Further, according to the method for calibrating dimensions of a scanning electron microscope according to the third aspect of the invention, since the dimension is directly calibrated by detecting the electron beam, there is no need to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

Further, according to the method of calibrating the dimensions of the scanning electron microscope of the third invention, it is not necessary to use the SEM image of the reference sample. Not affected by variation. For this reason, in dimension calibration, it is possible to reduce variation in dimension calibration between SEMs.

Further, according to the dimension correction method for a scanning electron microscope of the third invention, a switching element made of a material having higher electron beam resistance than a conventional photoresist reference sample can be used.

Further, in the method for calibrating dimensions of a scanning electron microscope according to the third invention, a plurality of control electrodes are arranged separately from each other, and the electron beam scans one control electrode and then scans another control electrode. By measuring the scanning time, which is the time required to perform the scanning, it is possible to measure not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the control electrodes. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the method for calibrating dimensions of a scanning electron microscope according to the third invention, when a plurality of control electrodes are arranged,
If three or more control electrodes are arranged separately from each other and the scan time between the control electrodes at a plurality of different locations is measured, it is possible to measure the variation in the scan time between different partial regions. As a result, not only the variation in scanning over the entire scanning width of the electron beam but also the variation in scanning time between partial regions between control electrodes can be measured. By adjusting each scanning electron microscope so that the degree of variation in the scanning time in the region is substantially the same, the relative dimensional calibration of the scanning electron microscope can be performed.

In the method for calibrating dimensions of a scanning electron microscope according to the third aspect of the present invention, when three or more control electrodes are arranged, one of the control electrodes other than the outermost one is subjected to reference control. The switching element is placed on the sample stage such that the reference control electrode is located at a position irradiated by the undeflected electron beam, and the reference control electrode is arranged in a symmetrical position across the reference control electrode. If the scanning time is measured for each of the two control electrodes, the bias of the electron beam of the scanning electron microscope can be detected by comparing the scanning times between the reference control electrode and each control electrode. .

In the method for calibrating dimensions of a scanning electron microscope according to the third aspect of the present invention, the switching element may include a MOS.
If a switching element having an FET structure is used and a portion where a gate electrode of the MOS FET structure is exposed is used as a control electrode, a current between a source region and a drain region of the MOS FET structure can be detected as an electric signal. Thereby, the dimension calibration can be performed by detecting the electron beam.

(Fourth invention) If the width of the stripe shape of the control electrode is known, the scanning speed of the electron beam can be directly measured by measuring the time during which the electron beam scans the control electrode. Can be. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed without using an SEM image.

In the method for calibrating dimensions of a scanning electron microscope according to the fourth invention, a MOS is used as a switching element.
If a switching element having an FET structure is used and a portion where a gate electrode of the MOS FET structure is exposed is used as a control electrode, a current between a source region and a drain region of the MOS FET structure can be detected as an electric signal. Thereby, the dimension calibration can be performed by detecting the electron beam.

(Fifth Invention) According to the electron beam detecting apparatus of the fifth invention, by irradiating the control electrode of the switching element with the electron beam, the electron beam is detected as an electric signal output from the switching element. can do.

Further, when the switching element of the electron beam detector of the fifth invention is mounted on the sample stage of the scanning electron microscope and the control electrode of the switching element is irradiated with an electron beam, the output from the switching element is obtained. An electron beam of a scanning electron microscope can be detected as the electric signal to be transmitted.

(Sixth Invention) According to the dimensional calibration apparatus for a scanning electron microscope of the sixth invention, the switching element is mounted on the sample stage of the scanning electron microscope, and is used as a control electrode of the switching element. When the electron beam is irradiated, the electron beam can be detected as an electric signal output from the switching element. Further, when the time from when the electron beam scans the control electrode to the next scan of the control electrode (hereinafter, also referred to as a scanning time) is measured from the electric signal, it is calculated as 1 for each scan of the electron beam. The scanning time, which is the time required for the electron beam to scan in each scan, can be measured. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, the relative dimensional calibration between the plurality of scanning electron microscopes is performed. Can be.

In the dimensional calibration apparatus for a scanning electron microscope according to the sixth aspect of the present invention, if a plurality of control electrodes are arranged spaced apart from each other, and a partial scanning time between the plurality of control electrodes is measured. Can be. As a result, it is possible to measure not only the variation in the scanning time of each scan over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the control electrodes. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the dimensional calibration apparatus for a scanning electron microscope according to the sixth invention, when a plurality of electrodes are arranged, preferably, when three or more control electrodes are arranged apart from each other, three or more control electrodes are arranged. It is possible to measure the scanning time between the control electrodes in the different partial regions, which are sandwiched between two different sets of two control electrodes among the electrodes. As a result, it is possible to measure the variation in scanning time between different partial regions.

Further, in the dimensioning apparatus for a scanning electron microscope according to the sixth invention, if three or more control electrodes are arranged apart from each other, one of the control electrodes other than the outermost one is used as a reference control electrode. The switching element is mounted on the sample stage such that the reference control electrode is located at a position irradiated by the undeflected electron beam, and the two control electrodes are arranged symmetrically with respect to the reference control electrode. , The scanning time can also be measured. As a result, by measuring the scanning time for each of the two control electrodes that are symmetrical with respect to the reference control electrode, the scanning times between the reference control electrode and the respective control electrodes are compared with each other, and the electron microscope The deviation of the electron beam can be detected.

In the dimensioning device for a scanning electron microscope according to the sixth invention, a MOS is used as a switching element.
If a switching element having an FET structure is used and a portion where a gate electrode of the MOS FET structure is exposed is used as a control electrode, a current between a source region and a drain region of the MOS FET structure can be detected as an electric signal. Thereby, the dimension calibration can be performed by detecting the electron beam.

In the dimensional calibration apparatus for a scanning electron microscope according to the sixth invention, if the width of the stripe shape of the control electrode is known, the time during which the electron beam scans over the control electrode is measured. In addition, the scanning speed of the electron beam can be directly measured. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

(Seventh invention) According to the electron beam detection method of the seventh invention, the electron beam is detected as a change in the electric resistance of the superconductor by irradiating the superconductor with the electron beam. Can be.

Further, the superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the seventh aspect, a weaker electron beam can be detected as compared with the case where the switching element is used.

(Eighth Invention) According to the electron beam detection method for a scanning electron microscope of the eighth invention, the superconductor placed on the sample stage of the scanning electron microscope is irradiated with the electron beam. Thereby, the electron beam can be detected as a change in the electric resistance of the superconductor.

In addition, the superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the eighth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used.

(Ninth Invention) According to the dimensional correction method for a scanning electron microscope of the ninth invention, the superconductor placed on the sample stage of the scanning electron microscope is irradiated with an electron beam. Then, the electron beam is detected as a change in the electric resistance of the superconductor, and the time (scanning time) from the scanning of the control electrode by the electron beam to the next scanning of the control electrode is determined from the electric signal. Measure. As a result, it is possible to measure the scanning time, which is the time required for the electron beam to scan in one scan for each scan of the electron beam. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

According to the dimensional calibration method for a scanning electron microscope of the ninth aspect, since the dimensional calibration is performed directly by detecting the electron beam, there is no need to use the SEM image of the reference sample. Therefore, no error occurs when counting the number of dots in the image of the reference sample. Also, there is no variation among the measurers who count the number of dots.

Further, according to the dimensional calibration method for a scanning electron microscope of the ninth aspect, it is not necessary to use an SEM image of a reference sample. Not affected by variation. For this reason, in dimension calibration, it is possible to reduce variation in dimension calibration between SEMs.

The superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the ninth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

In the dimensional calibration method for a scanning electron microscope according to the ninth aspect of the present invention, a plurality of superconductors are arranged separately from each other, and after the electron beam scans one superconductor, the other superconductor is scanned. By measuring the time between scanning the body,
It is possible to measure not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the superconductors. As a result, the SEM can be calibrated by adjusting the SEM so that the variation in the scanning time between the partial region of the SEM and the entire region is substantially the same. Further, by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same,
The relative dimensional calibration of the scanning electron microscope can be performed.

In the dimensional configuration method for a scanning electron microscope according to the ninth invention, when a plurality of superconductors are arranged, three or more superconductors are arranged separately from each other, and
By measuring the scanning time between the superconductivity at a plurality of different locations, it is possible to measure the variation in the scanning time between different partial regions. Then, by adjusting the scanning electron microscope so that the degree of variation in the scanning time in the plurality of partial regions is substantially the same, relative dimensional calibration of the scanning electron microscope can be performed.

In the method for calibrating dimensions of a scanning electron microscope according to the ninth aspect, when three or more superconductors are arranged, one of the superconductors other than the outermost superconductor may be used. Is a reference superconductor, and this reference superconductor is placed at a position irradiated by an undeflected electron beam, and two superconductors are arranged at positions symmetrical with respect to the reference superconductor. If you measure the scan time for each body,
By comparing the scanning times between the reference superconductor and each superconductor, the bias of the electron beam of the electron microscope can be detected.

(Tenth Invention) In the dimension correction method for a scanning electron microscope according to the tenth invention, since the width of the stripe shape of the superconductor is known, the time during which the electron beam scans the superconductor is determined. Is measured, the scanning speed of the electron beam can be directly measured. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

In addition, the superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the tenth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

(Eleventh Invention) According to the electron beam detector of the eleventh invention, when the superconductor is irradiated with an electron beam, the superconducting state is broken. An electron beam can be detected.

Further, the superconductor as the electron beam detector of the eleventh invention is placed on a sample stage of a scanning electron microscope, and the superconductor cooled to maintain the superconducting state is irradiated with the electron beam. Irradiates the superconducting state,
As a change in the electric resistance of the superconductor, an electron beam of a scanning electron microscope can be detected.

Further, the superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the eleventh aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

(Twelfth Invention) According to the dimensional calibration apparatus for a scanning electron microscope of the twelfth invention, the superconductor is placed on the sample stage of the scanning electron microscope to maintain the superconducting state. By irradiating the cooled superconductor with an electron beam,
The superconducting state is broken. Therefore, the electron beam can be detected as a change in the electric resistance of the superconductor. Further, from the change in the electric resistance, the time (scanning time) between the scanning of the superconductor by the electron beam and the next scanning of the superconductor is measured. The scanning time, which is the time required for the electron beam to scan in each scan, can be measured. Then, the variation in the scanning time can be known. In addition, by adjusting each scanning electron microscope so that the degree of variation in the scanning time between the plurality of scanning electron microscopes is substantially the same, it is possible to calibrate the dimensions of the scanning electron microscope.

Further, the superconducting state is usually broken only by irradiation with an extremely weak electron beam. Therefore, in the twelfth aspect, a weaker electron beam can be detected as compared with the case where the switching element is used. As a result, since the weak electron beam becomes thin, the dimensional calibration can be performed with better accuracy.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect, if a plurality of superconductors are arranged apart from each other, the scanning time between the plurality of superconductors can be measured. As a result, it is possible to measure not only the variation in the scanning over the entire scanning width of the electron beam but also the variation in the scanning time in the partial region between the superconductors. As a result, the relative dimensional calibration of the scanning electron microscope is adjusted by adjusting each scanning electron microscope so that the degree of variation in the scanning time in the partial region between the plurality of scanning electron microscopes is substantially the same. It can be performed.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect, if three or more superconductors are arranged apart from each other, a plurality of different sets of the three or more superconductors are different from each other. By measuring the scanning time between the superconductors in the different partial regions sandwiched between the two superconductors, it is possible to measure the variation in the scanning time between the different partial regions.

Furthermore, if three or more superconductors are arranged,
One of the superconductors other than the outermost superconductor is used as a reference superconductor, and the sample stage is positioned so that the reference superconductor is located at a position irradiated by an undeflected electron beam. When the dimensional configuration device is placed on the top and the scanning time is measured for each of the two superconductors arranged at positions symmetrical with respect to the reference superconductor, the two superconductors are symmetric with respect to the reference superconductor. By measuring the scanning time for each of the two superconductors, it is possible to detect the bias of the electron beam of the electron microscope by comparing the scanning times between the reference superconductor and the respective superconductors. it can.

In the dimensional calibration apparatus for a scanning electron microscope according to the twelfth aspect, if the width of the stripe shape of the superconductor is known, the time during which the electron beam scans over the superconductor is measured. Thus, the scanning speed of the electron beam can be directly measured. As a result, not only can the variation in the scanning speed of the electron beam be known, but also the absolute dimensional calibration of the scanning electron microscope can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for explaining a dimension calibration device of a scanning electron microscope according to a first embodiment.

FIG. 2 is a view from the electron beam source side of a scanning electron microscope,
FIG. 3 is a schematic diagram showing a scanning path of an electron beam.

FIG. 3 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the first embodiment, and is a diagram in which a switching element and an electron beam scanning section are overlapped.

FIG. 4 is a graph of an output of the switching element according to the first embodiment.

FIG. 5 is a configuration diagram for explaining a dimension correction device of a scanning electron microscope according to a third embodiment.

FIG. 6 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the third embodiment, in which a switching element and an electron beam scanning section are overlapped.

FIG. 7 is a graph of the output of the switching element according to the third embodiment.

FIG. 8 is a configuration diagram for explaining a dimension correction device of a scanning electron microscope according to a fourth embodiment.

FIG. 9 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the fourth embodiment, and is a diagram in which a switching element and a scanning section of an electron beam are overlapped.

FIG. 10 is a graph of the output of the switching element according to the fourth embodiment.

FIG. 11 is a configuration diagram for explaining a dimension calibration device of a scanning electron microscope according to a sixth embodiment.

FIG. 12 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the sixth embodiment, and is a diagram in which a switching element and an electron beam scanning section are overlapped.

FIG. 13 is a graph of an output of the dimension calibration device according to the sixth embodiment.

FIG. 14 is a configuration diagram for explaining a dimensional configuration device of a scanning electron microscope according to an eighth embodiment.

FIG. 15 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the eighth embodiment, and is a diagram in which a dimension calibration device and an electron beam scanning section are overlapped.

FIG. 16 is a graph of an output of the dimension calibration device according to the eighth embodiment.

FIG. 17 is a configuration diagram for explaining a dimensional calibration device for a scanning electron microscope according to a ninth embodiment;

FIG. 18 is a diagram for explaining a dimension calibration method of the scanning electron microscope according to the ninth embodiment, and is a diagram in which a dimension calibration device and an electron beam scanning section are overlapped.

FIG. 19 is a graph of an output of the dimension calibration device according to the ninth embodiment.

[Explanation of symbols]

 10: Dimension calibration device, switching element 12: control electrode, gate electrode 14: semiconductor substrate 16: source region 18: drain region 20: source side terminal 22: drain side terminal 24: rectangular, observation target region 26: first point 28 : 2nd point 30: 1st scanning section 32: 3rd point 34: 4th point 36: 2nd scanning section 38: Moving path 40: 5th point 42: 6th point 44: Final scanning section 46 : First irradiation position 48: Second irradiation position 50: Dimension calibration device, switching element 52: First control electrode, first gate electrode 54: Second control electrode, second gate electrode 56: First source region 58: Drain Region 60: second source region 62: first source side terminal 64: drain side terminal 66: second source side terminal 68: first irradiation position 7 : Second irradiation position 72: Third irradiation position 74: Fourth irradiation position 80: Dimension calibration device, switching element 82: First control electrode, first gate electrode 84: Second control electrode, second gate electrode 86: First Third control electrode, third gate electrode 88: first source region 90: first drain region 92: second source region 94: second drain region 96: first source side terminal 98: first drain side terminal 100: second Source side terminal 102: Second drain side terminal 104: First irradiation position 106: Second irradiation position 108: Third irradiation position 110: Fourth irradiation position 112: Fifth irradiation position 114: Sixth irradiation position 120: Dimension calibration Device 122: Substrate 124: Peltier cooling element 126: Superconductor 128: First terminal 130: Second terminal 132: First irradiation position 134: Second irradiation position 136: Dimension calibration Positive device 138: 1st superconductor 140: 2nd superconductor 142: 1st terminal 144: 2nd terminal 146: 3rd terminal 148: 4th terminal 150: 1st irradiation position 152: 2nd irradiation position 154: Third irradiation position 156: Fourth irradiation position 160: Dimension calibration device 162: First superconductor 164: Second superconductor 166: Third superconductor 168: First terminal 170: Second terminal 172: Third Terminal 174: Fourth terminal 176: Fifth terminal 178: Sixth terminal 180: First irradiation position 182: Second irradiation position 184: Third irradiation position 186: Fourth irradiation position 188: Fifth irradiation position 190: Sixth Irradiation position

Claims (27)

[Claims] 1. An electron beam detection method, comprising: detecting an electron beam by detecting an electric signal output from a switching element that performs a switching operation when an exposed control electrode is irradiated with the electron beam. 2. A switching element, which performs a switching operation when an electron beam is irradiated on an exposed control electrode, is mounted on a sample stage of a scanning electron microscope so that the electron beam scans over the control electrode. An electron beam detection method for a scanning electron microscope, wherein an electron beam is detected by detecting an electric signal output from the switching element. 3. The electron beam detection method for a scanning electron microscope according to claim 2, wherein a switching element having a MOS FET structure is used as the switching element, and a gate electrode of the MOS FET structure is used as the control electrode. An electron beam detecting method for a scanning electron microscope, comprising: detecting a current between a source region and a drain region of the MOS FET structure as the electric signal using an exposed portion. 4. A switching element, which performs a switching operation when an electron beam is irradiated on an exposed control electrode in a stripe shape as viewed from above, is mounted on a sample stage of a scanning electron microscope. It is mounted so as to scan, and by detecting an electric signal output from the switching element, measuring a time from scanning of the control electrode by the electron beam to scanning of the control electrode next time. Characteristic calibration method for scanning electron microscope. 5. The method for calibrating dimensions of a scanning electron microscope according to claim 4, wherein a plurality of control electrodes are provided separately from each other and arranged so that an electron beam scans one control electrode and then another control electrode. A dimensional calibration method for a scanning electron microscope, wherein a scanning time which is a time until scanning is measured. 6. The method for calibrating dimensions of a scanning electron microscope according to claim 5, wherein three or more control electrodes are arranged separately from each other, and the scanning times between the control electrodes at a plurality of different positions are respectively set. A method for calibrating dimensions of a scanning electron microscope, characterized by measuring. 7. The method for calibrating dimensions of a scanning electron microscope according to claim 6, wherein one of the control electrodes other than the outermost one is a reference control electrode, and the reference control electrode is deflected. To be illuminated by the unirradiated electron beam
A scanning electron microscope, wherein the switching element is mounted on the sample stage, and the scanning time is measured for each of the two control electrodes arranged symmetrically with respect to the reference control electrode. Dimension calibration method. 8. A switching element, which performs a switching operation when an electron beam is irradiated on an exposed control electrode having a known stripe-shaped width when viewed from above, is mounted on a sample stage of a scanning electron microscope. A scanning electron microscope, which is mounted so as to scan over a control electrode, and detects an electric signal output from the switching element to measure a time during which an electron beam irradiates the control electrode. Dimension calibration method. 9. The method for calibrating dimensions of a scanning electron microscope according to claim 4, wherein a switching element having a MOS FET structure is used as the switching element, and the switching element having the MOS FET structure is used as the control electrode. A method for calibrating dimensions of a scanning electron microscope, wherein a current between a source region and a drain region of the MOS FET structure is detected as the electric signal using a portion where a gate electrode is exposed. 10. An electron beam detection device comprising a switching element that performs a switching operation when an electron beam is irradiated on an exposed control electrode. 11. A control electrode having a stripe-shaped exposed control electrode as viewed from above, and comprising a switching element that performs a switching operation when the control electrode is irradiated with an electron beam. Calibration device for scanning electron microscope. 12. The size calibration device for a scanning electron microscope according to claim 11, wherein a plurality of control electrodes are arranged apart from each other. 13. The size calibration device for a scanning electron microscope according to claim 12, wherein three or more control electrodes are arranged apart from each other. 14. The dimensional configuration device for a scanning electron microscope according to claim 11, wherein the switching element has a MOS FET structure, and the control electrode has a portion exposing a gate electrode of the MOS FET structure. A dimensional calibration device for a scanning electron microscope characterized by comprising: 15. The size calibration device for a scanning electron microscope according to claim 11, wherein the width of the stripe shape of the control electrode is known. 16. A method for detecting an electron beam, comprising: detecting an electron beam by detecting an electric resistance of a superconductor, wherein a superconducting state is broken when irradiated with an electron beam. . 17. A superconductor whose superconducting state is broken when irradiated with an electron beam is placed on a sample stage of a scanning electron microscope so that the electron beam scans over the superconductor, An electron beam detection method for a scanning electron microscope, wherein an electron beam is detected by detecting an electric resistance of the superconductor. 18. A superconducting state which is broken when irradiated with an electron beam. A superconductor having a stripe shape as viewed from above is scanned on a sample stage of a scanning electron microscope by the electron beam. Detecting the electric resistance of the superconductor to measure the time from scanning of the superconductor by the electron beam to the next scanning of the superconductor. Method for calibrating the dimensions of a scanning electron microscope. 19. The method for calibrating dimensions of a scanning electron microscope according to claim 18, wherein a plurality of said superconductors are arranged separately from each other, and an electron beam scans one superconductor before another. A method for calibrating the dimensions of a scanning electron microscope, comprising measuring a time required for scanning a superconductor. 20. The method for calibrating dimensions of a scanning electron microscope according to claim 18, wherein three or more superconductors are arranged side by side apart from each other, and the scanning time between the superconductors at a plurality of different places is determined. A method for calibrating the dimensions of a scanning electron microscope, characterized by measuring each. 21. The method for calibrating dimensions of a scanning electron microscope according to claim 20, wherein one of the superconductors other than the outermost superconductor is a reference superconductor, and the reference superconductor is a reference superconductor. The body is placed at a position irradiated by an undeflected electron beam, and the scanning time is measured for each of the two superconductors arranged symmetrically with respect to the reference superconductor. A method for calibrating dimensions of a scanning electron microscope, characterized in that: 22. A superconductor having a known stripe-shaped width when viewed from above is broken on a sample stage of a scanning electron microscope. Dimensional calibration of a scanning electron microscope, wherein a conductor is placed so as to scan, and a time for irradiating the superconductor with an electron beam is measured by detecting an electric resistance of the superconductor. Method. 23. An electron beam detecting device comprising a superconductor whose superconducting state is broken when irradiated with an electron beam. 24. A dimensional calibration of a scanning electron microscope, comprising a superconductor having a stripe shape as viewed from above, which breaks a superconducting state when irradiated with an electron beam. apparatus. 25. The dimension correcting device for a scanning electron microscope according to claim 24, wherein a plurality of said superconductors are arranged separately from each other. 26. The dimensional calibration apparatus for a scanning electron microscope according to claim 25, wherein three or more superconductors are arranged apart from each other. 27. The size calibration device for a scanning electron microscope according to claim 24, wherein the width of the stripe shape of the superconductor is known.