JPH1164234A - Method and device for detecting foreign matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect foreign matters adhering to the surface of a semiconductor wafer in distinction from crystal defects, etc., existing on the surface of the semiconductor wafer. SOLUTION: A semiconductor wafer 2 is irradiated with a laser beam 4 from a laser light source 5, and scattered light from the wafer 2 irradiated with the laser beam 4 are detected by means of a plurality of photodetectors 6a, 6b, 6c, 6d, 6e, and 6f which are arranged so that the angles of elevation to the photodetectors 6a, 6b, 6c, 6d, 6e, and 6f from the irradiating point 4a of the laser beam 4 on the surface of the wafer 2 may become different from each other. Then, the intensity distribution of the scattered light is acquired by comparing the intensities of the scattered light detected by means of the detectors 6a, 6b, 6c, 6d, 6e, and 6f with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign matter detecting device and a foreign matter detecting method for detecting foreign matter attached to the surface of a semiconductor wafer.

[0002]

2. Description of the Related Art Most of the causes of defective semiconductor devices are caused by foreign substances adhering to the surface of a semiconductor wafer. In addition, if the design rules are further refined in the future, the pattern structure formed on the semiconductor wafer will be further refined, and it is expected that the failure rate of semiconductor devices will increase.

[0003] In order to detect foreign substances adhering to the surface of a semiconductor wafer, various foreign substance detection devices have been developed. FIG. 7 shows a typical conventional foreign matter detection device.

FIG. 7 is a perspective view showing a conventional foreign matter detection device. As shown in FIG.
Is a stage 103 on which the semiconductor wafer 102 is mounted.
A laser light source 105 for irradiating the surface of the semiconductor wafer 102 with a laser beam 104 from an oblique direction; and a photodetector 108 for detecting scattered light 107 generated by irradiating the foreign matter 106 on the semiconductor wafer 102 with the laser beam 104. And

[0005] The foreign substance detecting device 10 configured as described above
First, while irradiating the surface of the semiconductor wafer 102 with the laser beam 104 emitted from the laser light source 105, the stage 10 is driven by a stage driving means (not shown).
3 is driven in the illustrated X direction or Y direction. As a result, the laser beam 104 scans over the semiconductor wafer 102.

At this time, when the laser beam 104 is applied to the foreign material 106 attached to the semiconductor wafer 102, scattered light 107 reflected by the foreign material 106 is generated in addition to the normal regular reflected light 109. Therefore, by detecting the scattered light 107 by the photodetector 108, the foreign matter 106 attached to the surface of the semiconductor wafer 102 can be detected.

[0007]

However, at present,
COP on the mirror-polished surface of the semiconductor wafer
(Crystal Originated Parti
It is known that a crystal defect called cle) exists. When a laser beam is applied to the crystal defect, scattered light is generated in the same manner as when the foreign object is applied. In detecting foreign matter, it is necessary to distinguish between foreign matter and crystal defects, but it is impossible to distinguish between the two with a conventional foreign matter detection device as described above.

Further, during the process of manufacturing a semiconductor device, it is necessary to detect foreign substances on the surface of the semiconductor wafer when a pattern structure is formed on the surface of the semiconductor wafer. However, when a fine pattern structure is irradiated with a laser beam, diffracted light in a specific direction is generated. for that reason,
If the photodetector is located in the diffraction direction of the diffracted light, the diffracted light becomes noise and cannot be distinguished from the scattered light from the foreign matter and the diffracted light.

Accordingly, an object of the present invention is to provide a foreign matter detection method and a foreign matter detection device capable of detecting foreign matter adhering to the surface of a semiconductor wafer separately from crystal defects existing on the surface of the semiconductor wafer. It is still another object of the present invention to provide a foreign matter detection method and a foreign matter detection device capable of detecting foreign matter attached on a pattern structure formed on the surface of a semiconductor wafer.

[0010]

According to the present invention, there is provided a foreign matter detection method and foreign matter detection apparatus, comprising:
This is based on the fact that the characteristics of the elevation angle distribution are significantly different.

FIG. 8 is a schematic diagram showing the scattered light intensity due to crystal defects and the scattered light intensity due to foreign matter. On the surface of the semiconductor wafer 201 shown in FIG.
Are attached, and on the left side of the figure, COP which is a crystal defect is
203 is present.

The scattered light 205a generated by irradiating the foreign material 202 with the laser beam 204a
It has almost the same intensity in all directions of elevation from 04a '. On the other hand, the scattered light 205b generated by irradiating the COP 203 with the laser beam 204b has an intensity strongly deviated in a vertical elevation direction from the laser beam irradiation point 204b '.

Therefore, the method for detecting foreign matter according to the present invention comprises the steps of irradiating a surface of a semiconductor wafer with a laser beam;
By a plurality of photodetectors arranged so that elevation angles from the irradiation point of the laser beam on the surface of the semiconductor wafer are different from each other, detecting scattered light from the semiconductor wafer irradiated with the laser beam,
Comparing the intensities of the scattered light detected by the photodetectors with each other to obtain an intensity distribution of the scattered light.

As described above, for example, the scattered light generated by irradiating a foreign material with a laser beam and the scattered light generated by irradiating a crystal defect with a laser beam are, for example, elevation angles from the laser beam irradiation point. The intensity distribution of the scattered light in the directions is different. However, according to the foreign matter detection method as described above, since the scattered light from the detected object on the surface of the semiconductor wafer is detected from various elevation angles, it is possible to know the intensity distribution of the scattered light from the detected object. Therefore, the presence of foreign matter, crystal defects, and the like on the surface of the semiconductor wafer is confirmed.

Further, after the step of obtaining the intensity distribution of the scattered light, the obtained intensity distribution of the scattered light is
If the laser beam has substantially the same intensity in all elevation directions from the laser beam irradiation point, the object that caused the scattered light is determined to be foreign matter attached to the surface of the semiconductor wafer, and the laser beam If the intensity is deviated in the vertical elevation direction from the irradiation point, the object that caused the scattered light is determined to be a crystal defect existing on the surface of the semiconductor wafer, and specified from the irradiation point of the laser beam. When the intensity in the direction is strong, by having a configuration having a step of judging the detection object that caused the scattered light as a pattern structure formed on the surface of the semiconductor wafer, the detection object on the surface of the semiconductor wafer, Foreign substances adhering to the surface of the semiconductor wafer, crystal defects existing on the surface of the semiconductor wafer, and pattern structures formed on the surface of the semiconductor wafer are distinguished.

In addition, the step of irradiating the surface of the semiconductor wafer with a laser beam includes the step of scanning the surface of the semiconductor wafer with the laser beam. It is automatically adjusted to foreign substances and the like attached to the surface of the wafer.

Further, the foreign matter detecting device of the present invention comprises a stage on which a semiconductor wafer is mounted, a laser light source for irradiating a laser beam on the surface of the semiconductor wafer, and a laser light source for irradiating the semiconductor wafer with the laser beam. In a foreign matter detection device having a light detector for detecting scattered light, a plurality of the light detectors are provided, and each of the light detectors has a different elevation angle from a laser beam irradiation point on the surface of the semiconductor wafer. With such an arrangement, the above-described foreign matter detection method of the present invention is optimally performed.

Further, the laser beam scanning means for scanning the surface of the semiconductor wafer with the laser beam is provided, so that the irradiation point of the laser beam is Etc. automatically adjusted.

Further, the laser light source may be a continuous wave laser light source for continuously irradiating a laser beam or a pulse oscillation laser light source for irradiating a laser beam intermittently.

Further, the laser beam may be applied to the semiconductor wafer perpendicular to the surface of the semiconductor wafer, or the laser beam may be applied to the semiconductor wafer obliquely with respect to the surface of the semiconductor wafer. Irradiation may be adopted.

Further, the laser beam may have only a polarization component in a specific direction.

In addition, some or all of the plurality of photodetectors may be photodetectors that detect only a specific polarization component, and some or all of the plurality of photodetectors may be a detector array. It is good also as composition which is a type photodetector.

Further, at least one of foreign substance observing means for observing an object detected by the foreign substance detecting device and foreign substance analyzing means for analyzing a component of the detected object is provided. Is desirable.

Further, the foreign matter observation means is an electron microscope,
It is preferable to use an ion microscope or an atomic force microscope.

Further, the foreign substance analyzing means is preferably an X-ray detector, an Auger electron detector, a time-of-flight secondary ion mass spectrometer, or a laser microprobe mass spectrometer.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a perspective view showing a first embodiment of a foreign matter detection device according to the present invention.

As shown in FIG. 1, a foreign matter detection device 1 of the present embodiment includes a stage 3 on which a semiconductor wafer 2 is mounted,
The laser beam 4 is applied to the surface of the semiconductor wafer 2 from above vertically.
And a light detector 6a, 6b, 6c, 6 for detecting scattered light generated by irradiating the laser beam 4 to a foreign substance or the like attached to the surface of the semiconductor wafer 2.
d, 6e and 6f. Each photodetector 6a, 6b, 6
c, 6d, 6e, and 6f are irradiation points 4a of the laser beam 4.
Are installed in the foreign matter detection device 1 at equal angular intervals on an arc centered at. That is, each photodetector 6a, 6
The b, 6c, 6d, 6e, and 6f are installed in the foreign object detection device 1 so that the elevation angles from the irradiation point 4a of the laser beam 4 are different from each other.

In the foreign substance detection device 1 configured as described above, first, the laser beam 4 emitted from the laser light source 5
While irradiating the surface of the semiconductor wafer 2, the stage 3 is driven in the illustrated X direction or Y direction by a stage driving device (not shown) as a laser beam scanning unit. Thus, the laser beam 4 scans over the semiconductor wafer 2 and the irradiation point 4a of the laser beam 4 can be automatically adjusted to a foreign substance or the like attached to the surface of the semiconductor wafer 2.

At this time, when the laser beam 4 is irradiated on the foreign matter or the like on the semiconductor wafer 2, the laser beam 4 is reflected by the foreign matter or the like, and scattered light is generated. Therefore, the photodetector 6
a, 6b, 6c, 6d, 6e, and 6f, the scattered light is detected from various elevation angles, and the intensity distribution of the scattered light is obtained by comparing the detection intensities of the respective photodetectors. The presence of foreign matter or the like on the surface can be confirmed.

FIG. 2 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where foreign matter exists at the irradiation point of the laser beam.

As shown in FIG. 2, when the foreign material 7 is irradiated with the laser beam 4, the foreign material 7 reflects the laser beam 4, and generates scattered light 8a, 8b, 8c, 8d, 8e, 8f. As described with reference to FIG. 8, the scattered light 8a, 8b, 8c, 8 generated by irradiating the foreign material 7 with the laser beam 4
Since d, 8e, and 8f have substantially the same intensity in all directions of elevation from the foreign material 7, all the photodetectors 6a, 6f
b, 6c, 6d, 6e, and 6f, and their detection intensities are substantially uniform.

FIG. 3 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where a crystal defect exists at a laser beam irradiation point.

As shown in FIG. 3, COP which is a crystal defect
When the laser beam 4 is irradiated on the COP 9, scattered lights 10a, 10b, 10c, 10d, 10e, and 10f are generated from the COP 9. As described with reference to FIG. 8, the scattered light 10a, 10b,
Since 10c, 10d, 10e, and 10f have intensities strongly deviated in the vertical elevation direction, the intensity of the scattered lights 10c and 10d generated at a high angle is the strongest, and the intensity of the scattered lights 10a and 10f generated at a low angle. Is the weakest. Correspondingly, the photodetectors 6c and 6d have the strongest received light intensity of the scattered light detected by each photodetector, and the photodetectors 6a and 6f have the weakest received light intensity.

As described above, the scattered light from the foreign material 7 attached to the semiconductor wafer 2 has a uniform detection intensity at each photodetector, whereas the scattered light from the COP 9 is at each photodetector. The detection intensity is different. Therefore, the scattered light from the detected object on the semiconductor wafer 2 was detected by the photodetector, and the intensity of the scattered light from the detected object was obtained by comparing the scattered light detection intensities of the respective photodetectors with each other. Later, the obtained intensity distribution by the detected object is converted into a general intensity distribution of the scattered light by the foreign matter 7 attached to the surface of the semiconductor wafer 2 and a general intensity distribution of the scattered light by the COP 9 existing on the surface of the semiconductor wafer 2. The foreign matter 7 adhering to the surface of the semiconductor wafer 2 and the semiconductor wafer 2 were evaluated by comparing with the intensity distribution.
Can be detected separately from the crystal defects existing on the surface of.

FIG. 4 is a perspective view showing the foreign matter detecting apparatus shown in FIG. 1 in a state where a pattern structure exists at a laser beam irradiation point.

In the pattern structure 11, fine wiring and the like are formed at minute intervals, so that when the pattern structure 11 is irradiated with the laser beam 4, diffracted light in a specific direction, which is one of the scattered lights, is generated. 12a and 12b occur. The laser beam 4 does not reflect or scatter in other directions. Therefore, the diffracted lights 12a, 12a,
12b is detected, other photodetectors 6a, 6c,
In 6d and 6f, neither reflected light nor scattered light is detected.

FIG. 5 is a perspective view showing the foreign matter detecting device shown in FIG. 1 in a state where foreign matter and a pattern structure are present at a laser beam irradiation point.

As shown in FIG. 5, when the laser beam 4 is applied to the foreign material 7 and the pattern structure 11, the laser beam 4 is reflected by the foreign material 7 and scattered light 8a, 8b, 8c, 8
d, 8e, and 8f are generated, and the pattern structure 11 generates diffracted lights 12a and 12b having a high intensity in a specific direction. Then, the light detectors 6a, 6c, 6d, and 6f detect the scattered lights 8a, 8c, 8d, and 8f with uniform intensity. On the other hand, the scattered lights 8b, 8
e, the diffracted lights 12a and 12b are also detected, so that the detection intensities of the photodetectors 6b and 6e are equal to the photodetectors 6a, 6c,
It becomes larger than the detection intensity in 6d and 6f.

Therefore, the scattered light from the detected object on the semiconductor wafer 2 is detected by the photodetector, and the scattered light detection intensities of the respective photodetectors are compared with each other. Is obtained, the intensity distribution of the detected object is converted to the general intensity distribution of scattered light due to the foreign matter 7 attached to the surface of the semiconductor wafer 2 and the pattern structure 11 formed on the surface of the semiconductor wafer 2. The evaluation is made in comparison with the general intensity distribution of the diffracted light due to the pattern structure 11 formed on the surface of the semiconductor wafer 2.
Even if the foreign matter 7 is attached on the surface,
And the pattern structure 11 can be detected separately.

Although the foreign object detecting device 1 of the present embodiment uses six photodetectors 6a, 6b, 6c, 6d, 6e and 6f, the number of installed photodetectors is six. Not limited to The arrangement of the photodetectors is not limited to the arrangement shown in FIG.

(Second Embodiment) FIG. 6 is a perspective view showing a second embodiment of the foreign matter detection device of the present invention.

As shown in FIG. 1, the foreign matter detecting device 21 of the present embodiment comprises a stage 2 on which a semiconductor wafer 22 is mounted.
3, a laser light source 25 for irradiating the surface of the semiconductor wafer 22 with the laser beam 24 from an oblique direction, and a scattered light or the like generated by irradiating the laser beam 24 to a foreign substance or the like attached to the surface of the semiconductor wafer 22. Photodetector 26
a, 26b, 26c, 26d, 26e, 26f, 26g
And Each photodetector is installed in the foreign substance detection device 21 at equal angular intervals on an arc centered on the irradiation point 24a of the laser beam 24. That is, each photodetector is installed in the foreign substance detection device 21 such that the elevation angles of the laser beam 24 from the irradiation point 24a are different from each other.

The foreign object detecting device 21 configured as described above
First, while irradiating the surface of the semiconductor wafer 22 with the laser beam 24 emitted from the laser light source 25, the stage 23 is driven in the illustrated X direction or Y direction by the stage driving means (not shown). As a result, the laser beam 24 scans over the semiconductor wafer 22.

When there is no foreign matter or the like at the irradiation point 24a of the laser beam 24, only regular reflection light 24b of the laser beam 24 is generated on the surface of the semiconductor wafer 22,
No reflected light or scattered light is detected by any of the photodetectors.
However, when foreign matter, crystal defects, or a pattern structure (both not shown) are present at the irradiation point 24a of the laser beam 24, scattered light and diffracted light are generated as described in the first embodiment. . Therefore, by detecting the scattered light from the detection object on the semiconductor wafer 22 with the photodetector and comparing the detection intensities of the respective photodetectors with each other to obtain the intensity distribution from the detection object, the first embodiment As in the case of the embodiment, the detection object can be detected by distinguishing between the foreign matter and the crystal defect, and even if the detection object is a foreign matter adhered on the pattern structure, the foreign matter and the pattern structure can be detected separately.

In the foreign substance analyzer 21 of this embodiment, since the laser light source 25 is installed not obliquely above the semiconductor wafer 22 but obliquely, the photodetector is also installed vertically above the semiconductor wafer 22. ing. Therefore, the scattered light from the semiconductor wafer 22 can be detected from more angles, so that the intensity distribution of the scattered light can be more accurately obtained.

In the foreign substance detecting device 21 of the present embodiment, the seven photodetectors 26a, 26b, 26c, 26d, 26
Although the example using e, 26f, and 26g was shown, the number of photodetectors to be installed is not limited to seven. Further, the arrangement of each photodetector is not limited to the arrangement shown in FIG.

Further, in the foreign substance detection devices 1 and 21 of the first embodiment and the present embodiment, the stage 3 and the stage 3 are driven by a stage driving device (not shown) as a laser beam scanning means.
Although an example using a method in which the laser beams 4 and 24 scan the semiconductor wafers 2 and 22 by driving the laser light source 23 is shown, instead of using a stage driving device, a laser light source driving device (not shown) is used. 5 and 25 and drive the laser beams 4 and 24 to the semiconductor wafers 2 and 2
2 may be configured to scan. Further, the laser light sources 5 and 25 may be either continuous wave laser light sources that continuously irradiate the laser beams 4 and 24 or pulsed laser light sources that irradiate the laser beams 4 and 24 intermittently. Further, the laser beam 4 to be irradiated
24 may have only a polarization component in a specific direction. Further, some or all of the plurality of photodetectors may detect only a specific polarization component, or may be a detector array type photodetector.

Further, at least one of the foreign substance observing means and the foreign substance analyzing means may be combined with the foreign substance detecting devices 1 and 21 of the first embodiment and the present embodiment. An electron microscope, an ion microscope, an atomic force microscope, or the like can be used as the foreign substance observation means, and an X-ray detector, an Auger electron detector, a time-of-flight secondary ion mass spectrometer, And a laser / microprobe mass spectrometer.

First, an electron microscope, an ion microscope, and an atomic force microscope, which are means for observing foreign matter, will be described.

The electron microscope detects the position of a detected object such as a foreign substance or a crystal defect by the scattered light of the laser beams 4 and 24 and then irradiates the foreign substance or the like with an electron beam from an electron gun.
By detecting secondary electrons or reflected electrons generated from the detected object, a secondary electron image or a reflected electron image of the detected object is observed.

Further, the ion microscope detects the position of an object such as a foreign substance or a crystal defect in the same manner as described above, and then irradiates the object with an ion beam from an ion gun to generate a secondary beam generated from the object. By detecting ions, a secondary ion image of the foreign matter or the like is observed.

In addition, the atomic force microscope detects the position of a detection object such as a foreign substance or a crystal defect in the same manner as described above, and then moves the tip of the probe close to the detection object, thereby detecting the detection object and the probe. The shape of the object is observed by utilizing the interaction between atoms acting between the probe and the object while relatively moving the object.

Next, an X-ray detector as foreign matter analyzing means,
An Auger electron detector, a time-of-flight secondary ion mass spectrometer, and a laser microprobe mass spectrometer will be described.

The X-ray detector detects the position of a detected object such as a foreign substance or a crystal defect in the same manner as described above, and then irradiates the detected object with an electron beam from an electron gun to generate an X-ray generated from the detected object. Is detected to analyze the components of the detected substance.

Further, the Auger electron detection device detects the position of a detection object such as a foreign substance or a crystal defect in the same manner as described above, and then irradiates the detection object with an electron beam from an electron gun to generate the detection object. By detecting Auger electrons, the component analysis of the detected object is performed.

Further, the time-of-flight secondary ion mass spectrometer detects the position of an object such as a foreign substance or a crystal defect in the same manner as described above, and then irradiates the object with an ion beam from an ion gun. The component analysis of the detected object is performed by analyzing the flight time of secondary ions generated from the detected object.

Further, the laser microprobe mass spectrometer detects the position of a detected object such as a foreign substance or a crystal defect in the same manner as described above, and then irradiates the detected object with an ion beam from an ion gun. The secondary ions generated from the above are guided to a mass spectrometer to perform mass spectrometry, thereby performing elemental analysis and molecular structure analysis of the detected substance.

By providing the foreign substance detecting devices 1 and 21 with the above foreign substance observing means and foreign substance analyzing means, it is possible to not only detect foreign substances and the like, but also perform shape observation and component analysis of the foreign substances and the like. .

[0059]

As described above, according to the foreign matter detection method of the present invention, a step of irradiating a surface of a semiconductor wafer with a laser beam and a plurality of elevations from the irradiation point of the laser beam are different from each other. Detecting the scattered light from the semiconductor wafer by the photodetector, and having the step of comparing the detection intensity of the scattered light in each photodetector with each other to obtain the intensity distribution of the scattered light, The presence of foreign matter, crystal defects, and the like on the surface can be confirmed.

Further, the obtained intensity distribution of the scattered light is
If the object has substantially the same intensity in all elevation directions, the detected object is determined as a foreign substance.If the object has an intensity deviated in the vertical elevation direction, the detected object is determined as a crystal defect. When the intensity is strong, the method has a step of judging the object to be detected as a pattern structure so that the object to be detected on the surface of the semiconductor wafer can be made to have a foreign substance attached to the surface of the semiconductor wafer, crystal defects present on the surface of the semiconductor wafer, Can be distinguished from the pattern structure formed on the surface.

In addition, the step of irradiating the surface of the semiconductor wafer with the laser beam includes the step of scanning the surface of the semiconductor wafer with the laser beam, so that the irradiation point of the laser beam adheres to the surface of the semiconductor wafer. It can be automatically adjusted to a foreign substance or the like.

Further, in the foreign matter detection device of the present invention, a plurality of photodetectors for detecting scattered light from the semiconductor wafer irradiated with the laser beam have an elevation angle from the laser beam irradiation point on the surface of the semiconductor wafer. Since they are arranged so as to be different from each other, the above-described foreign matter detection method of the present invention can be optimally performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a foreign matter detection device of the present invention.

FIG. 2 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where a foreign matter exists at an irradiation point of a laser beam.

FIG. 3 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where a crystal defect exists at an irradiation point of a laser beam.

FIG. 4 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where a pattern structure exists at a laser beam irradiation point;

FIG. 5 is a perspective view showing the foreign matter detection device shown in FIG. 1 in a state where foreign matter and a pattern structure are present at an irradiation point of a laser beam.

FIG. 6 is a perspective view showing a second embodiment of the foreign matter detection device of the present invention.

FIG. 7 is a perspective view showing a conventional foreign matter detection device.

FIG. 8 is a schematic diagram showing scattered light intensity due to crystal defects and scattered light intensity due to foreign matter.

[Explanation of symbols]

1,21 Foreign particle detector 2,22 Semiconductor wafer 3,23 Stage 4,24 Laser beam 4a, 24a Irradiation point 5,25 Laser light source 6a, 6b, 6c, 6d, 6e, 6f, 26a, 26
b, 26c, 26d, 26e, 26f, 26g Photodetector 7 Foreign matter 8a, 8b, 8c, 8d, 8e, 8f, 10a, 10
b, 10c, 10d, 10e, 10f Scattered light 9 COP 11 Pattern structure 12a, 12b Diffracted light 24b Regular reflection light

Claims (20)

[Claims] Irradiating a laser beam on a surface of a semiconductor wafer; and a plurality of photodetectors arranged so that elevation angles from an irradiation point of the laser beam on the surface of the semiconductor wafer are different from each other. A step of detecting scattered light from the semiconductor wafer irradiated with a beam, and a step of comparing the detection intensity of the scattered light with each of the photodetectors with each other to obtain an intensity distribution of the scattered light. Detection method. 2. The method according to claim 1, wherein after the step of obtaining the intensity distribution of the scattered light, the obtained intensity distribution of the scattered light has an intensity substantially equal to an entire elevation direction from an irradiation point of the laser beam. If it has, the object that caused the scattered light is judged to be foreign matter attached to the surface of the semiconductor wafer, and if it has an intensity deviated in a vertical elevation direction from the irradiation point of the laser beam, the scattering The detected object that caused the light is determined to be a crystal defect existing on the surface of the semiconductor wafer, and when the intensity in a specific direction from the irradiation point of the laser beam is strong, the detected object that generates the scattered light is determined as 2. The foreign matter detection method according to claim 1, further comprising the step of judging a pattern structure formed on a surface of the semiconductor wafer. 3. The foreign matter detection method according to claim 1, wherein the step of irradiating the surface of the semiconductor wafer with a laser beam includes the step of scanning the surface of the semiconductor wafer with the laser beam. 4. A stage on which a semiconductor wafer is mounted, a laser light source for irradiating a laser beam on a surface of the semiconductor wafer, and a light for detecting scattered light from the semiconductor wafer irradiated with the laser beam. In a foreign matter detection device having a detector, a plurality of the photodetectors are provided, and each of the photodetectors is arranged so that elevation angles from an irradiation point of the laser beam on a surface of the semiconductor wafer are different from each other. A foreign matter detection device characterized by the above-mentioned. 5. The foreign matter detection device according to claim 4, further comprising a laser beam scanning unit for scanning the surface of the semiconductor wafer with the laser beam. 6. The foreign matter detection device according to claim 4, wherein the laser light source is a continuous wave laser light source that continuously emits a laser beam. 7. The foreign matter detection device according to claim 4, wherein the laser light source is a pulse oscillation type laser light source that irradiates a laser beam intermittently. 8. The foreign matter detection device according to claim 4, wherein the laser beam is applied to the semiconductor wafer perpendicularly to a surface of the semiconductor wafer. 9. The foreign matter detection device according to claim 4, wherein the laser beam is applied to the semiconductor wafer from an oblique direction with respect to the surface of the semiconductor wafer. 10. The foreign matter detection device according to claim 4, wherein the laser beam has only a polarization component in a specific direction. 11. The foreign object detection device according to claim 4, wherein a part or all of the plurality of photodetectors are photodetectors that detect only a specific polarization component. 12. A photo detector according to claim 4, wherein a part or all of said plurality of photo detectors are detector array type photo detectors.
The foreign matter detection device according to any one of the above. 13. The apparatus according to claim 4, further comprising at least one of foreign substance observing means for observing an object detected by said foreign substance detecting device, and foreign substance analyzing means for analyzing a component of said detected object. 13. The foreign matter detection device according to any one of 12 above. 14. The foreign matter detection device according to claim 13, wherein said foreign matter observation means is an electron microscope. 15. The foreign matter detection device according to claim 13, wherein said foreign matter observation means is an ion microscope. 16. The foreign matter detection device according to claim 13, wherein said foreign matter observation means is an atomic force microscope. 17. The foreign matter detecting device according to claim 13, wherein said foreign matter analyzing means is an X-ray detecting device. 18. The foreign matter detecting device according to claim 13, wherein said foreign matter analyzing means is an Auger electron detecting device. 19. The foreign matter detecting device according to claim 13, wherein said foreign matter analyzing means is a time-of-flight secondary ion mass spectrometer. 20. The foreign matter detecting device according to claim 13, wherein said foreign matter analyzing means is a laser microprobe mass spectrometer.