JPH10160685A - Irradiation position adjusting method for laser beam and electron beam, foreign material detecting device using laser beam, and scan-type electron microscope and foreign material analyzing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust irradiation position of laser beam and electron beam. SOLUTION: On an XY stage 21 driven in XY direction, a plate 51 comprising a part 51a which is different from surroundings in composition is set. Above the XY stage 21, a laser light source 32 which projects laser beam toward the XY stage 21, the first photo-detector 33 which detects scattered light of projected laser beam, and the second photo-detector 34 which detects reflected light of projected laser beam are assigned. With laser beam poured on the XY plate 21, the position where the intensity of reflected light detected with the second photo-detector 34 is maximum is taken as reference position of the XY stage 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign matter detection device for irradiating a focused laser beam to the surface of an object to optically detect a foreign matter attached to the surface of the object, and irradiating an electron beam to the surface of the object. Electron microscope for observing the object surface,
Furthermore, the present invention relates to a foreign substance analyzer for analyzing the composition of a foreign substance detected by a foreign substance detector, and more particularly, to a method for adjusting the irradiation position of a light beam or an electron beam used in the foreign substance analyzer.

[0002]

2. Description of the Related Art The high magnification of an electron microscope has made it possible to easily observe fine objects such as submicrons that cannot be confirmed with the naked eye, but it is troublesome to put an object to be viewed within the field of view of the microscope. It takes time and effort. For example, a fine particle attached to a semiconductor wafer, a fine wiring formed on a wafer, or a defective portion of a manufactured wiring has a diameter of 200 mm to 3 mm.
It is very difficult to search for and observe an object of 1 μm or less from the wafer area which is becoming 00 mm.

[0003] Detection of minute foreign matter from a large wafer area is realized by a foreign matter detection device that irradiates the wafer with light and detects light scattering from the foreign matter. The specific shape cannot be observed just by understanding. Therefore, after detecting the foreign matter with the foreign matter detection device, the sample is moved into the field of view of the electron microscope based on the position coordinates of the detected foreign matter, and the shape is observed by scanning electron microscope observation or energy dispersive X-ray analysis (EDX). ) Is generally performed.

[0004] As this kind of foreign substance analyzing apparatus, there is one described in, for example, JP-A-6-308039.
Hereinafter, this conventional foreign substance analyzer will be described with reference to FIG. The apparatus includes an XY stage 121 on which a wafer 111 to be inspected is mounted and which can move the wafer 111 in both XY directions, and a foreign matter detection device 1 for optically detecting foreign matter.
31 and a scanning electron gun 1 used as an electron beam source
41 and X from the wafer 111 irradiated with the electron beam.
An energy dispersive X-ray detector 142 for detecting energy and performing energy analysis, and a wafer 111 irradiated with an electron beam.
And a secondary electron detector 143 for detecting secondary electrons from the detector.

[0005] All of these devices and parts constituting the foreign substance analyzer are housed in a vacuum vessel (not shown).
In the vacuum container, the foreign matter detection device 131 and the scanning electron gun 141 are arranged apart from each other, and an X-ray detector 142 and a secondary electron detector 143 are arranged near the scanning electron gun 141. . The foreign object detection device 131 includes a laser light source that emits laser light, an optical lens system that narrows down the laser light from the laser light source, a light detection unit that detects the laser light, and the like. The scanning electron gun 141 can scan a certain area of the surface of an object with a narrowly focused electron beam, and includes an electron gun as an electron beam source, an electron lens system, an electron beam scanning system, and the like. . When the scanning electron gun 141 and the secondary electron detector 143 are combined,
An ordinary scanning electron microscope (SEM) is configured.

An XY stage 121 is disposed at the bottom of the vacuum vessel, and is provided with a foreign matter detector 131 and a scanning electron gun 14.
1, the wafer 111 can be moved in the XY directions to position the wafer 111 at a position immediately below the foreign matter detection device 131 or the scanning electron gun 141. XY stage 1
21 includes an X-direction encoder 122a for measuring the amount of movement in the X direction and a Y-axis for measuring the amount of movement in the Y direction.
A direction encoder 122b is attached.

Next, the operation of detecting, observing, and analyzing foreign matter by the above foreign matter detecting device will be described.

First, an XY control is performed by a drive control device (not shown).
The drive of the stage 121 is controlled, and the wafer 111 is arranged below the foreign matter detection device 131. Here, while the XY stage 121 is slightly moved in the XY directions, the
Irradiates the surface of the wafer 111 with laser light from the
The foreign substance on the wafer 111 is detected by observing the scattered light caused by the minute foreign substance adhered to the surface of the wafer 11 by the light detection unit of the foreign substance detection device 131. The readings of the X-direction encoder 122a and the Y-direction encoder 122b when detecting foreign matter on the surface of the wafer 111 indicate the position where the foreign matter is attached.

Next, the XY stage 121 is again driven and controlled to move the wafer 111 below the scanning electron gun 141, and the XY stage 121 is moved in the XY directions while referring to the surface position of the previously detected foreign matter. Then, the positioning is performed so that the foreign matter coincides with the focal point of the electron beam from the scanning electron gun 141. As a result, the foreign matter to be observed falls within the field of view of the X-ray detector 142 and the secondary electron detector 143.

Here, the secondary electron generated from the foreign matter by the electron beam emitted from the scanning electron gun 141 is detected by the secondary electron detector 143, so that the external shape of the foreign matter can be observed. Similarly, the scanning electron gun 14
By detecting and analyzing the characteristic X-rays generated from the foreign matter by the electron beam irradiated from 1 with the X-ray detector 142, the composition of the foreign matter can be analyzed by X-rays.

[0011]

The above-described conventional foreign matter analyzer is capable of detecting foreign matter adhering to the surface of an object, observing the outer shape of the detected foreign matter, and performing component analysis. The external shape observation operation and the component analysis operation require complicated operations by an operator, and are not suitable for use in a production line requiring a high throughput or for automatic measurement.

[0012] The reason is that the spot size of the laser light source used when foreign matter is detected by the foreign matter detection device,
When analyzing foreign matter, the spot size of the electron beam emitted from the scanning electron gun is greatly different from the spot size by orders of magnitude, and it is difficult to irradiate both at the same position. For example, the spot size of a semiconductor laser beam generally used as a laser light source of a foreign matter detection device is about 10 μm, and even if it is detected that a foreign matter exists within the range of the spot of the laser light, a scanning electron gun may be used. Generally, an electron beam to be irradiated is often used with a spot size of about 0.1 μm, so that it is not easy to accurately irradiate a foreign substance with the electron beam. This depends on whether the foreign object is hitting the electron beam,
Alternatively, it is not possible to determine whether or not a hit has occurred.

As described above, it is difficult to irradiate an electron beam to the position where a foreign substance is detected by a laser light source. At present, it is actually the case that an operator corrects the position while viewing a scanning electron microscope image. .

Accordingly, the present invention provides an adjustment method that can easily adjust the irradiation position of a laser beam or an electron beam,
It is a further object of the present invention to provide a foreign object detection device, a scanning electron microscope, and a foreign object analysis device capable of easily detecting, or observing and analyzing a minute object by applying these adjustment methods.

[0015]

In order to achieve the above object, a method for adjusting the irradiation position of a laser beam according to the present invention comprises the steps of: irradiating a laser beam from a laser light source to a sample placed on the stage; A method for adjusting the irradiation position of a laser beam when detecting a foreign substance attached to the surface of the sample by relatively moving a light source and detecting scattered light from the sample, One plate having a portion having a different composition was set on the stage, and the reflected light intensity generated by irradiating the plate with the laser beam was measured, and the change in the reflected light intensity was maximized. The position is used as a reference position for relative movement between the stage and the laser light source.

In the method for adjusting the irradiation position of an electron beam according to the present invention, the sample mounted on a stage is irradiated with an electron beam from an electron beam source, and the stage and the electron beam source are relatively moved. Characteristics X generated from the sample
A method of adjusting the irradiation position of the electron beam when observing the surface shape of the sample by detecting the line and performing the composition analysis of the sample, or detecting the secondary electrons. A single plate having different portions is placed on the stage, and characteristic X-rays generated by irradiating the electron beam to the portions having different compositions are detected. It is a reference position for relative movement with the electron beam source.

In the method for adjusting the irradiation position of a laser beam and an electron beam according to the present invention, the stage and the laser light source are relatively moved while irradiating the sample mounted on the stage with the laser beam from the laser light source. After detecting foreign matter attached to the surface of the sample by detecting scattered light from the sample, the detected foreign matter is irradiated with an electron beam from an electron beam source, and characteristic X-rays generated from the foreign matter are emitted. When performing the composition analysis of the sample by detecting, a method for adjusting the irradiation position of a laser beam and an electron beam,
A plate having a portion different in composition from the surroundings is placed on the stage, and the reflected light intensity generated by irradiating the plate with the laser beam is measured. After detecting the foreign matter with the position where becomes the reference position, the characteristic X-ray generated by irradiating the part having the different composition with the electron beam is detected, and the foreign matter is detected based on the position at that time. The stage and the electron beam source are relatively moved to the position at which the stage has been moved.

According to the present invention, the irradiation position of the laser beam or the electron beam on the stage is accurately recognized, and the irradiation position of the laser beam or the electron beam is adjusted. For this purpose, a single plate having a part with a composition different from that of the surroundings is placed on the stage, and changes in physical properties obtained by irradiating a part with a different composition with a laser beam or an electron beam are measured. Detect
The irradiation position of the laser beam or the electron beam is adjusted using the position at that time as a reference position.

When the plate is irradiated with the laser beam, the laser beam reflects at a reflectance depending on the composition of the irradiated portion. Therefore, by measuring the intensity of the reflected light, it is possible to know whether or not the laser beam is applied to a portion of the plate having a different composition. In other words, when the change in the measured reflected light intensity is maximum,
This means that the laser beam is applied to portions of the plate having different compositions. In addition, if a portion having a different composition is made convex or concave, the portion having a different composition is irradiated with the laser beam by detecting the presence or absence of scattered light generated by irradiating the portion with the laser beam. You can know. Then, the laser beam is irradiated to a desired position by adjusting the irradiation position of the laser beam with reference to the position at this time.

When the plate on the stage is irradiated with the electron beam, characteristic X-rays depending on the composition are generated from the portion irradiated with the electron beam. Therefore, by detecting the characteristic X-rays and analyzing the composition, it is possible to know whether or not the electron beam is irradiated on the portion of the plate having a different composition. By adjusting the irradiation position of the electron beam with reference to the position at this time, the electron beam is irradiated to a desired position.

Further, when a foreign substance on the sample surface is detected by laser beam irradiation, and characteristic X-rays are detected by irradiating the detected foreign substance with an electron beam, the composition analysis of the foreign substance is performed. The adjustment of the irradiation position and the adjustment of the irradiation position of the electron beam are performed in order, and the reference position of the irradiation of the laser beam and the reference position of the irradiation of the electron beam are matched, so that the electron beam is Is accurately irradiated to the position where the foreign matter is detected.

Further, by providing a plurality of portions having different compositions on the plate, the relative movement amount between the stage and the laser beam or the electron beam when the stage is aligned with respect to the portions having different compositions, and By comparing the actual spacing between portions having different compositions, the irradiation position error of the laser beam or the electron beam can be measured. Furthermore, by comparing the response of each detector obtained by irradiating a laser beam or an electron beam by making the areas of these portions having different compositions different from each other, the size of the foreign substance and the response of each detector can be compared. Relationship can be easily known.

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a perspective view showing a schematic configuration of an example of a foreign object detecting apparatus to which the present invention is applied.

A single plate 5 having a portion 51a having a composition different from that of the surroundings is provided on the XY stage 21 which is driven and controlled in the X and Y directions by a drive control device (not shown).
1 is installed. The XY stage 21 is for mounting a sample such as a semiconductor integrated circuit wafer to be inspected for foreign matter, and the plate 51 is arranged at a position not overlapping the sample.

The XY stage 21 has an X-direction encoder 22a for measuring the movement amount and position in the X direction, and a Y-direction encoder 2 for measuring the movement amount and position in the Y direction.
2b is attached. Note that a laser interferometer may be provided instead of each encoder for more precise position measurement.

Above the XY stage 21, a laser light source 32 for irradiating a laser beam toward the XY stage 21 is provided.
And a first photodetector 33 for detecting scattered light of the irradiated laser beam, and a second photodetector 34 for detecting reflected light of the irradiated laser beam. The laser beam emitted from the laser light source 32 is narrowed down narrowly through an optical lens system (not shown), and is irradiated as a spot light of about 10 μm. The positional relationship and the functions of the laser light source 32 and the photodetector 33 are the same as those of the conventional foreign matter detection device, and therefore, detailed description thereof will be omitted. Also, XY
Stage 21, laser light source 32 and photodetectors 33, 3
The mechanisms and components constituting the foreign matter detection device, such as 4, are housed in a vacuum vessel (not shown) as necessary.

Based on the above configuration, a sample is placed on the XY stage 21 and a laser light source 32 irradiates the sample surface with a laser beam, and scattered light caused by foreign substances adhering to the sample surface is converted into first light. The detection of foreign matter on the surface of the sample is performed by the detection by the detector 33.
The irradiation position of the laser beam with respect to the XY stage 21 is aligned.

For this purpose, the XY stage 21 is slightly moved so that the laser beam from the laser light source 32 is irradiated on the portion 51a of the plate 51 having a different composition. At this time, if the position where the plate 51 is set in advance is input to an external storage device such as a memory, the portion 51a having a different composition can be used.
X automatically until the laser beam is irradiated near
The Y stage 21 can be moved.

When the substance is irradiated with light, the reflected light intensity is:
It depends on the reflectance specific to the substance at the wavelength of the irradiated light. Therefore, when the laser beam hits the portion 51a having a different composition, the change of the reflected light intensity is changed by the second photodetector 34.
When the fine movement of the XY stage 21 is stopped at the point where the change in the intensity of the reflected light is greatest, the X-direction encoder 22a and the Y-direction encoder 22 at that time are stopped.
The reading of b is the position of the XY stage 21 when the laser beam is irradiated on the portion 51a having a different composition.

The size of the portion 51a having a different composition preferably matches the spot size of the laser beam to be irradiated. However, even when the spot size of the laser beam is larger than the size of the portion 51a having a different composition, In general, the intensity distribution of the light source is not constant within the spot, but has a distribution (Gaussian distribution) that becomes stronger toward the center. When stopped, there is no problem if it is considered that the portion 51a having a different composition is located at the center of the spot.

When the movement of the XY stage 21 is stopped, the readings of the X-direction encoder 22a and the Y-direction encoder 22b at that position are stored. Thereafter, if the XY stage 21 is moved with the stored position as the origin, it is possible to know which position on the XY stage 21 is irradiated with the laser beam with reference to the position of the portion 51a having a different composition. Can be irradiated with a laser beam. That is, by setting the position of the portion 51a having a different composition as the reference position for laser beam irradiation, the laser beam irradiation position can be easily adjusted. Then, the sample on the XY stage 21 is irradiated with a laser beam, and scattered light is detected by the first photodetector 33, thereby detecting foreign matter adhering to the sample surface.

When the XY stage 21 is slightly moved so as to irradiate the laser beam to the portion 51a having a different composition, the X-direction encoder 22a and the Y-direction encoder
If the output of the second photodetector 34 is stored together with the reading of the second photodetector 2b, by comparing the output with the size of the portion 51a having a different composition, the spot of the laser beam actually irradiated on the sample can be obtained. You can know the size. Since the spot size of the laser beam is determined by the position of the laser light source 32 and the optical lens system, or the position of the XY stage 21 in the vertical direction, it is possible to irradiate the desired spot size and the desired position by controlling these. Becomes possible.

Even when a plurality of light sources are used, after the first light source is aligned as described above, the relative position between the XY stage 21 and the first light source is fixed, and the second and subsequent light sources are fixed. If the positions of the light sources are similarly adjusted and aligned, it is possible to irradiate a plurality of laser beams to the same position with an arbitrary spot size.

Further, when the XY stage 21 is operated, an unavoidable error such as a backlash caused by the drive mechanism of the XY stage 21 occurs. Overlap can be eliminated. This also means that the repeatability of the XY stage 21 can be arbitrarily measured.

The above process can also be performed automatically by feeding back the output of the second photodetector 34 and finely moving the XY stage 21.

In this embodiment, the portions 51a having different compositions are used.
In the example described above, the change in reflected light intensity was used to detect
The same can be achieved by making the portion 51a having a different composition convex or concave and detecting scattered light generated when the convex or concave portion is irradiated with a laser beam. In this case, the scattered light can be detected using the first photodetector 33 used for detecting foreign matter.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 2 is a perspective view showing a schematic configuration of an example of a scanning electron microscope to which the present invention is applied. In FIG. 2, components having the same configuration as in the first embodiment are denoted by the same reference numerals as those in FIG.

As shown in FIG. 2, in this embodiment, as in the first embodiment, a portion 51 having a different composition from the surroundings is used.
A plate 51 having a is placed on the XY stage 21 on which a sample to be observed is placed. Above the XY stage 21, a scanning electron gun 41 used as an electron beam source, an X-ray detector 42 for detecting characteristic X-rays from a substance irradiated with the electron beam, and a substance irradiated with the electron beam Electron detector 43 for detecting secondary electrons from
And are arranged.

The scanning electron gun 41 is, for example, several μm.
The XY stage 21 can be scanned with a narrowly focused electron beam in an area of m squares.
A secondary electron image (that is, a scanning electron microscope image) can be obtained by detecting secondary electrons in Step 3. Also,
A characteristic X-ray corresponding to the composition is also emitted from the portion irradiated with the electron beam, and the composition analysis of the sample can be performed by detecting the characteristic X-ray with the X-ray detector 42 and performing energy analysis. The present scanning electron microscope also has a function as a composition analyzer. A mechanism that constitutes a scanning electron microscope and a composition analyzer, such as the XY stage 21, the scanning electron gun 41, the X-ray detector 42, and the secondary electron detector 43;
Parts are housed in a vacuum vessel (not shown) as necessary.

Based on the above configuration, a sample is placed on the XY stage 21, the surface of the sample is irradiated with an electron beam from the scanning electron gun 41, and secondary electrons generated from the sample are detected by the secondary electron detector 43. By doing so, the external shape of the sample or a specific portion of the sample is observed. Before that, the irradiation position of the electron beam with respect to the XY stage 21 is adjusted.

For this purpose, the XY stage 21 is moved so that the electron beam from the scanning electron gun 41 is irradiated on the portion 51a having a different composition on the plate 51. At this time, if the position where the plate 51 is set in advance is input to an external storage device such as a memory, the portion 51a having a different composition can be used.
The XY stage 21 can be automatically moved until the electron beam is irradiated to the vicinity of the XY stage. After irradiating the plate 51 with the electron beam, the characteristic X-rays emitted from the portion to which the electron beam is irradiated are next detected by the X-ray detector 42.
To detect. Then, it is measured whether or not the composition of the portion 51a having a different composition is detected while finely moving the XY stage 21. If the fine movement of the XY stage 21 is stopped at a position where the change in the composition is the maximum, the X direction at that time is stopped. The readings of the encoder 22a and the Y-direction encoder 22b are the positions when the electron beam is irradiated on the portion 51a having a different composition.

When the movement of the XY stage 21 is stopped, the readings of the X-direction encoder 22a and the Y-direction encoder 22b at that position are stored. Thereafter, if the XY stage 21 is moved with the stored position as the origin or the electron beam is scanned, which position on the XY stage 21 is irradiated with the electron beam with reference to the position of the portion 51a having a different composition. And it is possible to irradiate a desired position with an electron beam. That is, by setting the position of the portion 51a having a different composition as the reference position for the irradiation of the electron beam, the irradiation position of the electron beam can be easily adjusted. Then, the sample on the XY stage 21 is irradiated with an electron beam, and secondary electrons from the sample are detected by a secondary electron detector 43.
By detecting the above, the surface of the sample can be observed. Further, when foreign matter is attached to the sample, the foreign matter is irradiated with an electron beam, and characteristic X-rays from the foreign matter are detected by the X-ray detector 42, whereby the composition analysis of the foreign matter can be performed.

When the XY stage 21 is slightly moved so as to irradiate the electron beam to the portion 51a having a different composition, the X-direction encoder 22a and the Y-direction encoder 22
If the output of the X-ray detector 42 is stored together with the reading of b, by comparing the output with the size of the portion 51a having a different composition, the spot size of the electron beam actually irradiated on the sample can be determined. You can know. The spot size of the electron beam is determined by the setting and position of the lens system in the scanning electron gun 41 or the vertical position of the XY stage 21. By controlling these, the laser beam reaches the desired spot size and desired position. Can be irradiated.

Further, when the XY stage 21 is operated, an unavoidable error such as a backlash caused by the driving mechanism of the XY stage 21 occurs. Overlap can be eliminated. This also means that the repeatability of the XY stage 21 can be arbitrarily measured.

The above steps can be all automatically performed by feeding back the output of the X-ray detector 42 and finely moving the XY stage 21.

(Third Embodiment) Next, a third embodiment of the present invention will be described. FIG. 3 is a perspective view showing a schematic configuration of an example of the foreign substance analyzer to which the present invention is applied. In FIG. 3, the same components as those in the first embodiment and those in the second embodiment are denoted by the same reference numerals as those in FIGS.

In the present embodiment, the foreign matter adhering to the surface of the wafer 11 is detected by the foreign matter detecting device 31, and the detected foreign matter is observed by an electron microscope, and the composition is analyzed by energy dispersive X-ray analysis. The foreign matter detecting device 31 is for optically detecting foreign matter, and includes a laser light source that emits laser light, an optical lens system that narrows down the laser light from the laser light source, a light detection unit that detects laser light, and the like. The X-ray detector 42 detects characteristic X-rays from the wafer 11 irradiated with the electron beam and performs energy analysis. Further, on the XY stage 21, a plate 51 having a portion 51a having a composition different from that of the surroundings is provided as in the above-described embodiments.

That is, the foreign substance analyzer of the present embodiment is a combination of the foreign substance detector described in the first embodiment and the scanning electron microscope and the foreign substance analyzer described in the second embodiment. These devices and parts constituting the foreign substance analyzer of the embodiment are housed in a vacuum vessel (not shown).

Next, the operation of detecting, observing and analyzing foreign matter by the foreign matter analyzer of the present embodiment will be described.

First, in the same manner as in the first embodiment, the irradiation position of the laser beam from the foreign matter detection device 31 is aligned, and then the foreign matter attached to the surface of the wafer 11 is removed by the foreign matter detection device 31. To detect. The readings of the X-direction encoder 22a and the Y-direction encoder 22b at this time are stored.

Next, the XY stage 21 is moved below the scanning electron gun 41, and the irradiation position of the electron beam from the scanning electron gun 41 is adjusted in the same manner as in the second embodiment. Then, the XY stage 21 is moved to a position where the readings of the X-direction encoder 22a and the Y-direction encoder 22b are the same as the readings stored when the foreign object detection device 31 detects the foreign object. Since the reading of the X-direction encoder 22a and the Y-direction encoder 22b at the time of detecting a foreign object is based on the position of the portion 51a having a different composition, the irradiation position of the electron beam by the scanning electron gun 41 is also the portion 51a having the different composition. By using the position as a reference, it is possible to accurately irradiate the same position as the position where the foreign matter is detected with the electron beam.

As described above, the plate 51 is provided with the portion 51a having a different composition, and the portion 51a having the different composition is irradiated with a laser beam or an electron beam to obtain physical characteristics corresponding to each beam. By detecting the change, two types of beams can be aligned with one plate 51. The alignment of the two types of beams may be performed before the wafer 11 is inspected.

Thus, even if the foreign matter is minute in a large wafer area, the foreign matter can be easily irradiated with the electron beam, and the secondary electron detector 43 detects the secondary electrons. , And the composition analysis of the foreign matter by the X-ray detector 42 can be performed easily and in a short time.

In this embodiment, after the foreign matter is detected by the foreign matter detection device 31, the XY stage 21 is moved to observe and analyze the detected foreign matter. In some cases, the position repeatability of the XY stage 21 requires high accuracy. For example, when the size of the foreign matter is 1 μm or less, it may be necessary to narrow the scanning range of the electron beam to a range of 1 μm × 1 μm for composition analysis. At this time, the position reproducibility of the XY stage 21 is required to have an accuracy of 1 μm or less. In order to improve the accuracy of such position reproducibility, it is necessary to move the XY stage 21 at a low speed or use a costly high-precision stage, which directly affects the time required for inspection or the cost of the apparatus. May be exerted.

On the other hand, if each device is installed so that the laser beam irradiation position and the electron beam irradiation position coincide with each other without separating the foreign matter detection portion by the laser beam and the foreign matter detection portion by the electron beam, the measurement time can be reduced. You can keep it fast. The alignment of the laser beam is performed as in the first embodiment described above, and the alignment of the electron beam is performed as in the second embodiment. Matching becomes possible. In this case, too, of course, prevention of error superposition and measurement of the reproducibility of repetition of the XY stage 21 can be realized by the same method.

The above steps can be all automatically performed by feeding back the output of the X-ray detector 42 and finely moving the XY stage 21. That is, detection of foreign matter, observation of the outer diameter shape, and composition analysis can be performed fully automatically.

(Other Embodiments) In each of the embodiments described above, an example was described in which one portion having a different composition was used. However, by using a plurality of portions having different compositions,
It is also possible to correct the irradiation position error of the laser beam or the electron beam.

Since the size and interval of the portions having different compositions can be known with high accuracy by other measuring means, the alignment of the laser beam or the electron beam is performed for all the portions having different compositions, and the measurement is performed by the encoder. By comparing the amount of movement of the stage with the actual distance between parts with different compositions, it is possible to easily measure the irradiation position error of the laser beam or electron beam and the position error of the stage, and to correct and adjust them. it can.

Further, when the areas of the portions having different compositions are different from each other, the areas of the portions having different compositions, and the area of each detector obtained by irradiating a laser beam or an electron beam are different. By comparing the response, the relationship between the size of the foreign object and the response of each detector can be easily known, and can be used for calibration when measuring the size of the foreign object.

[0061]

As described above, according to the present invention, a plate having a portion having a composition different from that of the surroundings is provided on a stage, and when a sample on the stage is irradiated with a laser beam or an electron beam, the composition differs. By setting the portion as the reference position, adjustment of the irradiation position of the laser beam or the electron beam can be easily and fully automatically performed. In particular, when a foreign substance on a sample surface is detected by laser beam irradiation, secondary electrons are detected by irradiating the detected foreign substance with an electron beam, and the surface shape of the foreign substance is observed. When analyzing the composition of foreign matter by detecting the line,
Even a minute foreign substance in a large sample area can be easily and automatically irradiated with an electron beam at the same position as the position where the foreign substance is detected.

As a result, by applying the above-described adjustment of the irradiation position to a foreign substance detection device, a scanning electron microscope, or a foreign substance analyzer, it is possible to detect a foreign substance in a sample, observe the detected foreign substance, and further detect the detected foreign substance. Composition analysis can be performed easily and in a short time and fully automatically.

Further, by using a plurality of portions having different compositions, it is possible to correct the irradiation position error of the laser beam or the electron beam. Further, by making the portions having different compositions different in area, It can also be used for calibration when measuring the size of foreign matter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an example of a foreign object detection device to which the present invention is applied.

FIG. 2 is a perspective view showing a schematic configuration of an example of a scanning electron microscope to which the present invention is applied.

FIG. 3 is a perspective view showing a schematic configuration of an example of a foreign substance analyzer to which the present invention is applied.

FIG. 4 is a perspective view showing a schematic configuration of a conventional foreign matter analyzer.

[Explanation of symbols]

 Reference Signs List 21 XY stage 22a X-direction encoder 22b Y-direction encoder 31 Foreign object detector 32 Laser light source 33 First photodetector 34 Second photodetector 41 Scanning electron gun 42 X-ray detector 43 Secondary electron detector 51 Plate 51a Part with different composition

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/66 H01L 21/66 JL (72) Inventor Naojiro Ichikawa 2-703 Tachino, Higashiyamato-shi, Tokyo Inside Chemitronics Co., Ltd.

Claims (14)

[Claims] 1. A laser light source irradiates a laser beam onto a sample placed on a stage, the stage and the laser light source are relatively moved, and scattered light from the sample is detected. A method for adjusting the irradiation position of a laser beam when detecting a foreign substance adhering to the surface of a laser, wherein one plate having a portion different in composition from the surroundings is placed on the stage, The reflected light intensity generated by irradiating the beam to the plate is measured, and the position where the change in the reflected light intensity is maximized is set as the reference position for the relative movement between the stage and the laser light source. Position adjustment method. 2. A portion having a different composition is formed into a convex shape or a concave shape, scattered light generated by irradiating the portion having the different composition with the laser beam is detected, and a position at that time is determined by the stage and the laser light source. 2. The method for adjusting a laser beam irradiation position according to claim 1, wherein the reference position is a reference position for relative movement of the laser beam. 3. A stage in which a plurality of portions having the different compositions are provided on the plate, and the irradiation position of the laser beam is adjusted for the portions having the different compositions by measuring the reflected light intensity. A relative displacement amount between the stage and the laser light source is measured by measuring a relative displacement amount with the laser light source, comparing an actual interval between the plurality of different compositions and the relative displacement amount. 3. The irradiation position adjusting method of the laser beam according to 1 or 2. 4. A sample mounted on a stage is irradiated with an electron beam from an electron beam source, and a characteristic X-ray generated from the sample is detected while relatively moving the stage and the electron beam source. A method for adjusting the irradiation position of the electron beam when performing the composition analysis of the sample, wherein one plate having a portion having a composition different from the surroundings is set on the stage, and the electron beam is A method for adjusting an irradiation position of an electron beam, wherein characteristic X-rays generated by irradiating a portion having a different composition are detected, and a position at that time is used as a reference position for relative movement between the stage and the electron beam source. 5. A sample mounted on a stage is irradiated with an electron beam from an electron beam source, and secondary electrons generated from the sample are detected while relatively moving the stage and the electron beam source. A method of adjusting the irradiation position of the electron beam when observing the surface shape of the sample, wherein one plate having a portion different in composition from the surroundings is placed on the stage, A characteristic X-ray generated by irradiating a portion having a different composition with the electron beam, and setting the position at that time as a reference position for relative movement between the stage and the electron beam source. 6. The stage when a plurality of portions having different compositions are provided on the plate, and the irradiation position of the electron beam is adjusted for the portions having different compositions by detecting the characteristic X-rays. Measuring a relative movement amount with respect to the electron beam source, comparing an actual interval between the plurality of portions having different compositions with the relative movement amount, and determining a relative position error between the stage and the laser light source. Item 6. The method for adjusting a laser beam irradiation position according to Item 4 or 5. 7. The sample mounted on a stage by irradiating the sample with a laser beam from a laser light source while relatively moving the stage and the laser light source and detecting scattered light from the sample. After detecting foreign matter adhering to the surface of the sample, irradiating the detected foreign matter with an electron beam from an electron beam source and detecting characteristic X-rays generated from the foreign matter, the composition analysis of the sample is performed. A method of adjusting the irradiation position of a laser beam and an electron beam, wherein one plate having a part different in composition from the surroundings is placed on the stage, and the plate is irradiated with the laser beam. After measuring the intensity of the reflected light generated and detecting the foreign matter with the position where the change in the intensity of the reflected light is maximized as the reference position, the electron beam is applied to a portion where the composition is different. A characteristic X-ray generated by irradiation is detected, and a laser beam and an electron beam are used to relatively move the stage and the electron beam source to a position at which the foreign object is detected, based on the position at that time. Irradiation position adjustment method. 8. A laser light source for irradiating a sample placed on a stage with a laser beam, and a photodetector for detecting scattered light from the sample irradiated with the laser beam, wherein the laser A foreign matter detector that relatively moves the stage and the laser light source while irradiating a beam, and detects scattered light from the sample to detect foreign matter attached to the surface of the sample; A second light detector for detecting reflected light from the irradiated material, and a plate having a portion different in composition from the surroundings is provided on the stage, and the stage and the laser light source are provided. When the plate is irradiated with the laser beam, the plate is relatively moved with respect to a position where the change in the intensity of the reflected light measured by the second photodetector is maximum. A foreign matter detection device, characterized in that: 9. The foreign matter detection device according to claim 8, wherein a plurality of portions having different compositions are provided on the plate. 10. The foreign matter detection device according to claim 9, wherein the plurality of portions having different compositions have different areas. 11. An electron beam source for irradiating a sample placed on a stage with an electron beam, and an X-ray detector for detecting characteristic X-rays from the sample irradiated with the electron beam. A scanning X-ray microscope for observing the surface of the sample by detecting the secondary electrons while relatively moving the stage and the electron beam source, wherein a characteristic X-ray from a substance irradiated with the electron beam; And a plate having a portion having a composition different from the surroundings is provided on the stage, and the stage and the electron beam source are configured such that the electron beam has the composition. A scanning electron microscope, wherein characteristic X-rays generated by irradiating different portions are relatively moved with reference to a position detected by the X-ray detector. 12. The scanning electron microscope according to claim 11, wherein a plurality of portions having different compositions are provided on the plate. 13. A foreign object detection device for irradiating a sample mounted on a stage with a laser beam from a laser light source and detecting scattered light from the sample to detect a foreign object attached to the sample. An electron beam source for irradiating an electron beam, and an X-ray detector for detecting characteristic X-rays from the sample irradiated with the electron beam, wherein the foreign matter is detected after the foreign matter is detected by the foreign matter detection device. A foreign matter analyzer for irradiating the foreign matter with an electron beam from the electron beam source, detecting the X-rays with the X-ray detector, and analyzing the composition of the foreign matter. A plate having a plurality of plates, and a relative reference position between the stage and the laser light source at the time of detecting the foreign material is irradiated with the laser beam to the plate to detect the foreign material. The position where the change in the reflected light intensity detected by the position is the maximum, the relative reference position between the stage and the electron beam source when analyzing the composition of the foreign matter, Characteristic X caused by irradiating different parts
A foreign matter analyzer, wherein a line is set at a position detected by the X-ray detector. 14. The foreign matter analyzer according to claim 13, further comprising secondary electron detection means for detecting secondary electrons from a substance irradiated with the electron beam.