JP2003077969A - Dust particle detection method, its device and semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that minute dust particles exist during semiconductor manufacturing because LSI is made minute and contamination due to heavy metal elements or the like existing in a wafer or on the surface of the wafer can not be detected. SOLUTION: An atmosphere setting and holding system detected while suppressing Rayleigh scattering in which scattering light from the dust particles or the contamination is unnecessary in a specific atmosphere in a scattering light detection system is provided with a contamination detector for detecting scattering light detection from the dust particles existing on a substrate or contamination, and the contamination detector is provided with a substrate heating system for further previously heating the substrate prior to contamination detection. The above constituted contamination detector is installed in a doorway of each substrate of a vacuum processing device for semiconductor manufacturing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contamination detecting method and apparatus for detecting foreign matters and contamination existing on a substrate, or contaminant elements existing in the substrate with high accuracy, and a device therefor. The present invention relates to a semiconductor manufacturing line in which devices are arranged in a predetermined line.

[0002]

2. Description of the Related Art In semiconductor manufacturing, if a minute foreign substance exists on a wafer, it is likely that an insulation defect or a short circuit will occur on the wiring due to the presence of the minute foreign substance. Further, when an element such as a heavy metal exists on the wafer as the semiconductor element is miniaturized, the insulating film of the capacitor, the gate oxide film, or the like is easily broken or short-circuited due to the element. .

By the way, as a technique for detecting a minute foreign substance on a wafer, for example, Japanese Patent Application Laid-Open No. 63-1358 has been used.
No. 48 is cited. In this case, the wafer is irradiated with the laser, but when foreign matter is attached to the wafer, scattered light is generated by the foreign matter itself, and the foreign matter is detected by detecting the scattered light. It has become so. The foreign matter detected as described above is analyzed by a known technique such as laser photoluminescence or secondary X-ray spectroscopy (XMR).

In addition to the above literature,
EM Observation Of Defects In Juiced By Cu Contamination On Si (100) Surface "(Japanese Journal Of Applied Physics Vol. 27, Vol. 1
0, October 1988, pages L1819-L1821).
"TEM Observation of Defec
ts Induced by Cu Contamine
ation on Si (100) Surface (J
APANESE JOURNAL OF APPLIE
D PHYSICS Vol. 27, No. 10, OC
TOBER, 1988, pp. L1819-L182
1) ”means that when the Si substrate is heat-treated, C in the Si substrate is
The phenomenon that u is diffused and precipitated is introduced.

Further, "Applied Physics" (Vol. 51, No. 11 (1982), pp. 1246-1254) discusses the relationship between crystal defects and precipitation of contaminants.

[0006]

By the way, the reality is that the presence of minute foreign particles is gradually becoming a problem in the manufacture of semiconductors with the miniaturization of LSIs. However, such minute foreign matter can no longer be detected by the technique according to the above publication, let alone in the wafer,
Alternatively, contamination by heavy metal elements or the like existing on the wafer surface cannot be detected.

An object of the present invention is to provide a contamination detection method capable of detecting foreign matters and contamination existing on a substrate with high accuracy.

Another object of the present invention is to provide a contamination detecting method capable of detecting contaminant elements and the like existing in a substrate with high accuracy.

Further, another object of the present invention is to improve the accuracy of a contamination detecting device capable of detecting foreign matters and contamination existing on a substrate with good accuracy, and a contaminant element existing in the substrate with good accuracy. The present invention is to provide a contamination detection device capable of detecting.

Still another object of the present invention is to provide a semiconductor manufacturing line in which the degree of contamination of a substrate to be processed and the presence or absence of foreign matter can be easily detected in each vacuum processing apparatus for semiconductor manufacturing. It is in.

[0011]

The above object is achieved by detecting scattered light from a spot position on the substrate while suppressing unnecessary Rayleigh scattering when the entire surface of the substrate is scanned by the spot light.

Another object is achieved by detecting foreign matter or contamination after heating the substrate as a pretreatment.

Still another object is to provide a contamination detection device for detecting foreign matter or contamination existing on a substrate by detecting scattered light from the foreign matter or contamination, and a foreign matter or contamination in the scattered light detection system. Atmosphere setting that can detect scattered light in a specific atmosphere while suppressing unnecessary Rayleigh scattering.
This can be achieved by providing the holding system with the substrate heating system that preheats the substrate in advance of the contamination detection in the contamination detection device provided with the atmosphere setting / holding system.

Still another object is achieved by equipping each of the substrate processing entrances and exits of the vacuum processing apparatus for semiconductor manufacturing with the contamination detecting apparatus constructed as described above.

[0015]

In general, when the entire surface of the substrate is scanned by spot light, if foreign matter or contamination is present on the substrate, scattered light is generated at the location of the foreign matter, and the foreign matter is detected by detecting this scattered light. Alternatively, contamination can be detected. However, at that time, if the spot light is irradiated or reflected on the substrate surface in normal air, and if scattered light due to foreign matter or contamination is to be detected, the air will be emitted through the spot light irradiation path and the reflection path. Unnecessary Rayleigh scattering occurs due to molecules, and scattered Ray cannot be detected with a large S / N ratio because unnecessary Rayleigh scattering occurs due to air molecules even in the course of the path to the scattered light detection system. That is. Therefore, scattered light is detected in a specific atmosphere state in which unnecessary Rayleigh scattering is suppressed to be small (specifically, low pressure or low temperature, or an atmosphere state of a specific gas (one in which Rayleigh scattering is smaller than air)). By doing so, foreign matter and contamination can be detected with good accuracy.

Further, when the substrate is heated by, for example, laser beam scanning prior to detection of foreign matter or contamination, contaminant elements such as heavy metals existing in the substrate are diffused and collected on the substrate surface. As a result, the contaminant elements existing in the substrate can be detected. At that time, when the substrate is etched with the processing gas after being heated, or when the substrate is heated with a low potential portion or minute scratches formed on its surface, the contamination is particularly emphasized. The contamination can be detected with high accuracy.

Further, the contamination detecting device is generally configured to detect the foreign matter existing on the substrate or the scattered light from the contamination, but the foreign matter existing on the substrate or the contamination is detected from the foreign matter or the contamination. When a contamination detection device that detects by scattered light detection is equipped with an atmosphere setting / holding system that can detect scattered light from foreign matter or contamination in the scattered light detection system while suppressing unnecessary Rayleigh scattering in a specific atmosphere. , Not only the generation of unnecessary Rayleigh scattering on the spot light irradiation path and the reflection path can be suppressed, but also the Rayleigh scattering on the scattered light detection path of scattered light required for detecting foreign matter or contamination can be suppressed. Therefore, the foreign matter or the contamination can be detected with high accuracy. Further, in order to detect contaminant elements and the like existing in the substrate, a contamination detection device equipped with an atmosphere setting / holding system is further provided with a substrate heating system for preheating the substrate prior to contamination detection. At the least, the contaminant elements and the like existing in the substrate can be easily detected for the reasons described above.

Furthermore, when the substrate inlet / outlet of each vacuum processing apparatus as a component in the semiconductor manufacturing line is equipped with the contamination detecting apparatus configured as described above, before and after processing in each vacuum processing apparatus. It is possible to control pollution in the area.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to FIGS.

First, the contamination detecting apparatus according to the present invention will be described. FIG. 1 shows an example of the construction. As shown in the figure, the whole of this example is composed of a contamination depositing section 100, a contamination detecting section 200, and a contamination analyzing section 300. Of these, the contamination deposition part (heating part of the substrate as a sample) 100 is configured with a vacuum chamber 101 as a center, and a sample (substrate: specifically, a substrate taken into the vacuum chamber 101 from the outside through a sample inlet 102). Wafers, LCD TV substrates with TFTs, etc.)
3 is an infrared heater 10 in a state of being mounted on the mounting table 110.
The sample is taken out / intake 104 after being heated by 9.
It is adapted to be taken into the contamination detection unit 200 via the. The heating temperature at that time is measured by the thermometer 108, and the atmosphere in the vacuum chamber 101 is set and controlled by the gas reaction gas supply system 112, the reaction gas exhaust system 107, and the vacuum exhaust system 106. It has become a thing. Incidentally, an infrared heater 109 as a heating source,
The thermometer 108 as the temperature measuring means and the atmosphere setting control will be briefly described as follows.

That is, first, an infrared heater 1 is used as a heating source.
Besides 09, a filament type (halogen lamp, tungsten lamp, etc.) and a laser light source (Ar laser, excimer laser, YAG laser, CO ₂ laser, etc.) can be used. If the laser light from the laser light source is condensed and the sample 3 is scanned, the sample 3 can be easily heated. Also, since this method can be used to process only a limited area on the wafer, the TEG (TE
If a contamination evaluation region is formed on the ST ELEMENT GROUP), the contamination generated in each process can be evaluated.

As for the temperature measuring means, an infrared radiation type and a diffracted light detection type (Japanese Patent Laid-Open No. 62-88929).
It is also possible to measure the temperature of the sample 3 directly, such as the one described in Japanese Patent Publication No.), or to measure the temperature of the mounting table 110 on which the sample 3 is mounted. At that time, a contact thermometer such as a thermocouple can also be used.

Further, the atmosphere setting control will be explained. First, for the vacuum exhaust system 106 for vacuum exhausting the inside of the vacuum chamber 101, any one of a rotary pump, an oil diffusion pump, a turbo molecular pump, etc. is used. It may be one. However, during the heat treatment, it is necessary for the sample 3 to have a performance sufficient to maintain a sufficient degree of vacuum so as not to react with unexpected gas molecules in the atmosphere. Specifically, the degree of vacuum is preferably about 10 ⁻⁸ Torr, and for that purpose, it is desirable to roughly draw with a rotary pump and then draw with a turbo molecular pump or the like. Although the reaction gas exhaust system 107 is configured as a vacuum exhaust system, only the vacuum exhaust system 106 is normally used for vacuum exhaust. However, when the reaction gas is a harmful gas or a reactive gas, the reaction gas exhaust system 107 is used,
If the exhaust performance of the vacuum exhaust system 106 is insufficient,
It is designed to be used together with the vacuum exhaust system 106. Further, the reaction gas supply system 112 contains 1 such as O ₂ , N ₂ , CF ₂ or the like.
More than one kind of gas is accumulated in the cylinder 104, but one or more kinds of these gases are selected and the mixer 1 is selected.
After being mixed in 03, it is supplied into the vacuum chamber 101 via the flow rate controller 105.

The contamination deposit 100 has been described above. Next, the contamination detection unit 200 will be described. It includes a stage system 219, a vacuum chamber system 220 and a light source system 22.
2, a scattered light detection system 223 and a signal processing system 224. As shown in the figure, the stage system 219 is arranged such that the sample 3 is placed on the Z stage 21
Since the sample 3 is placed on the Θ stage 204 and the X stage 202, the sample 3 is rotatable and movable in the X and Z directions. Further, the vacuum chamber system 220 is provided with the sample take-out / take-in ports 104 and 217.
1 and a vacuum exhaust system 203 for evacuating the same, the light source system 222 also includes a He—Cd laser light source (wavelength 325 nm) 206, an optical window (a part of the vacuum chamber 201 partition wall) 218, It is composed of a condensing optical system 221 and a mirror (for scanning) 207. Further, the scattered light detection system 223 includes an objective lens 208, a detector 209 and a cooler (for cooling the detector 209) 210, and a signal processing system 224 further includes a light source blinking controller 212, a synchronization detection circuit 213, and a binary circuit 214. And a data processing unit 216. In this example, only the detector 209 is cooled to about −180 ° C. by liquid nitrogen, but in addition to this, the analog portion including the synchronization detection circuit 213 and the binary circuit 214 may be cooled. . This is because the noise in the analog part is reduced by cooling.

After the sample 3 is placed on the mounting table 205, the stage system 219 is moved so that the sample is positioned on the focal plane of the scattered light detection system 223 by the autofocus system 211 under the control of the controller 215. It is finely adjusted, but after this adjustment, while rotating the Θ stage 204, the X stage 20
If the sample 2 is moved, the entire surface of the sample 3 is covered by the mirror 20.
It is scanned by the laser light spot from 7. Incidentally, as the autofocus system 211, an appropriate system such as a stripe pattern projection system or a laser oblique illumination system can be adopted.

FIG. 2 shows the configuration of another example of the scattered light detection system 223. As shown, the objective lens 20
8 and the detector 209 may be provided outside the vacuum chamber 201. However, in the case of such a configuration, an optical window (which constitutes a part of the partition wall of the vacuum chamber 201) 229 is required. At that time, the objective lens 208
Must be aberration-corrected including the thickness and position of the optical window 229. In some cases, optical window 229 may be configured as part of objective lens 208.

FIG. 3 also shows an example in which an infrared heater 109 forming a part of the contamination depositing portion 100 is provided outside the vacuum chamber 101. In this case, the entire vacuum chamber 101 is configured as the sample chamber 113. The sample chamber 113 itself is movable in the direction of the contamination detection unit 200 so as to be located directly below the objective lens 208, and
A part of the vacuum chamber 101 partition wall is configured as an optical window 111. The vacuum chamber 101 is the contamination detection unit 200.
When the sample is moved to (1) (a part of the sample 3 and the like is indicated by a broken line), scattered light from the inside of the sample chamber 113 is detected outside the vacuum chamber 101 through the optical window 111. The other circumstances are the same as in the case of FIG. In addition,
In this example, of the stage system 219, the Θ stage 204
Is changed to the Y stage 205, because it is necessary to move the vacuum chamber 101 toward the contamination detection unit 200. Of course, the Θ stage 204 and the Y stage 205 may be used together.
Note that the autofocus system is not shown in FIG.

Now, returning to FIG. 1 again, the contamination analysis unit 300
The contamination analysis in the contamination analysis unit 300 is performed in the vacuum chamber 301 under the control of the control unit 309. A sample table 305, a Z stage 318, a Θ stage 304 and an X stage 302 are provided in a vacuum chamber 301 provided with a sample take-out / intake port 217, a sample take-out port 307 and a vacuum exhaust system 303. A scanning electron microscope 306 is provided for this purpose. At that time, the scanning electron microscope 30
It is desirable that the No. 6 be equipped with a secondary X-ray spectroscopic analysis (XMR) means 308. Instead of the scanning electron microscope 306 or the like, a scanning tunnel microscope, secondary ion mass spectrometric means or the like may be provided.

Now, to explain the operation as a whole, the contamination detection apparatus according to the present invention shown in FIG. 1 evaluates foreign matter and contamination existing on the sample 3, With this, it is possible to evaluate the degree of cleanliness in various LSI manufacturing apparatuses (for example, a dry processing apparatus 1 such as an etching apparatus, a CVD apparatus, a sputtering apparatus, an exposure apparatus, or a wet processing apparatus 2 such as a cleaning apparatus or a wet etching apparatus). Has become. During the evaluation, a contamination evaluation dummy sample is passed through the LSI manufacturing apparatus, and the sample 3 thus obtained is first placed on the contamination deposition unit 100. Further, when the TEG region on the wafer described above is used, it may be a sample during device fabrication instead of the dummy sample. The sample 3 is heated in the contamination deposition portion 100 prior to the detection of contamination. The reason why this heating is required is clear from the paper already mentioned in the section [Prior Art]. According to the article, Cu ₆ Si having a size of 0.2 × 0.2 μm and a depth of 0.5 μm is deposited and formed on a defect portion on the surface of a Si substrate by heat treatment at a temperature of 1150 ° C. for 1 hour in an N ₂ atmosphere. Although it has been reported that this phenomenon occurs, it is not known in detail in that paper that Cu atoms contained in the Si substrate are diffused by heat treatment and gettered to Si defects. It is explained that there is. By analogy with this, it is expected that a similar phenomenon will occur with other metals having a small solid solubility limit in Si, such as Fe, Cr, and W.

In order to utilize the above phenomenon, the contamination detection unit 10
In Sample No. 0, Sample 3 was heat-treated at about 1000 ° C. for about 1 hour. The processing temperature and the processing time at that time are standard, and the temperature and the time are not limited thereto but can be set appropriately. Further, in order to make the above phenomenon due to heating more reliable, crystal defects (scratches) are formed on the surface of the sample 3 so that a low potential portion is formed. The scratch is the core of contamination deposition. However, it is necessary that the scratches are sufficiently small so as not to become noise when it is detected whether or not contamination is deposited. In particular,
The size is preferably 0.01 μm or less.
The scratches at this time are described in the literature (Nanometer Scale).
Structure of of Silicon b
y Direct Indentation), it is effective to use a scanning tunneling microscope. Further, at that time, when a specific gas species is selected as the atmosphere in the vacuum chamber 101, it is possible to selectively grow only a specific element.

Next, the operation of the contamination detecting section 200 will be described. The heat-treated sample 3 is then placed on the mounting table 2 next.
05, the height of the surface of the sample 3 is adjusted so as to match the focus plane of the scattered light detection system 223, and thereafter, the sample 3 is rotated by the Θ stage 204 and further moved by the X stage 202. The entire surface is scanned by the laser light spot while moving in the direction. When foreign matter or contamination is present at a certain scanning position, the laser light scattered by the foreign matter or contamination is detected by the detector 209 via the objective lens 208, and the foreign matter or contamination is detected by detecting the scattered light. It can be determined that they are doing. In this example, the vacuum chamber 20
Since No. 1 is evacuated to a vacuum state prior to detection of contamination, unnecessary Rayleigh scattering is suppressed as much as possible, and the scattered light is increased in S / N ratio to make the detector 20
9 can be detected. At that time, instead of exhausting the vacuum chamber 201 to a vacuum state as much as possible, the atmosphere in the vacuum chamber 201 may be filled with a specific gas (one in which Rayleigh scattering is less likely to occur than air) or may be kept in a low temperature state. The same effect can be obtained. Generation of scattered light is suppressed by keeping the inside of the vacuum chamber 201 in a low pressure state, and FIG. 4 shows the situation. This figure was calculated with reference to "The Principle of Optics III" (translated by Tokai University Press, pp. 950-962), translated by Max Born and Emil Wolf, translated by Tohru Kusagawa and Eiji Yokota. As can be seen from this figure, the scattered light output due to Rayleigh scattering of air molecules under 1 atm is at the same level as that of a foreign substance having a size of about 0.05 μm. Therefore, when air is normally present, the size of the foreign matter is the detection limit. However, if the inside of the vacuum chamber 201 is evacuated and the pressure is reduced to, for example, 100 mT0rr, the size of the foreign matter can be detected up to about 0.01 μm. It should be noted that the operation of the pollution analyzer 300 is not directly related to the present invention, and therefore its operation is omitted.

Although the pollution detecting device according to the present invention has been described above, this pollution detecting device can be incorporated in a semiconductor manufacturing line. When a contamination detecting device is provided at the substrate entrance / exit of each vacuum processing apparatus constituting the semiconductor manufacturing line, the contamination can be easily controlled before and after the processing in each vacuum processing apparatus.

Finally, a method of preparing a sample used for evaluating the performance of the contamination detection device according to the present invention will be described. When evaluating the contamination detecting device, 0.
Although it is necessary to attach fine particles having a size of about 01 μm to 0.03 μm onto the sample, it has been difficult to obtain a sample to which such fine particles are attached so far. The reason is that even if standard fine particles such as polystyrene are used, the adhesion position on the sample becomes unclear, or the mixture in ultrapure aggregates. Was difficult.

By the way, "Journal of Science and Technology B6 (6) .NOV / DE
C 1988 "(J.VAC.SCI.TECHNO
L. B6. NOV / DEC 1988) page 1877-
In 1880 papers, size 0.02-0.03μ
It has been reported that m depot particles were created. Figure 5
As shown in FIG. 2, a scanning tunneling microscope 1 and a tungsten carbon (W (C
O) ₆ ) is used to form the deposit particles 3 of that size on the surface of the wafer 4, and this technique makes it possible to obtain a sample for performance evaluation. As shown in FIG. 6, the depot particles 3 are substantially regularly attached to the surface of the performance evaluation sample 5, and therefore,
Since the position of the depot particles is clear as compared with the method using standard particles, the evaluation can be performed quantitatively and quickly.

[0035]

As described above, according to the first to fourth aspects, foreign matters and contaminations existing on the substrate can be detected with high accuracy, and according to the fifth to eighth aspects. ,
The contaminant elements and the like existing in the substrate can be detected with high accuracy. Further, according to claim 9, foreign matter or contamination existing on the substrate can be detected, and in the case of claim 10, contamination elements etc. existing in the substrate can be detected with high accuracy. A device is available. Furthermore, according to the eleventh aspect, the degree of contamination of the substrate to be processed and the presence or absence of foreign matter can be easily evaluated and detected in each of the vacuum processing apparatuses constituting the semiconductor manufacturing line.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an example of a pollution detection device according to the present invention.

FIG. 2 is a diagram showing a configuration of another example of the scattered light detection system shown in FIG.

FIG. 3 is a diagram showing a configuration of another example of the contamination depositing portion shown in FIG. 1.

FIG. 4 is a diagram for explaining how Rayleigh scattering due to air molecules changes depending on atmospheric pressure conditions.

FIG. 5 is a diagram for explaining a method of creating a depot particle in a certain paper.

FIG. 6 is a diagram showing a sample for evaluating the performance of the pollution detection device according to the present invention.

[Explanation of symbols]

3 ... Sample (substrate), 100 ... Contamination deposit part, 101, 20
DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 109 ... Infrared heater, 200 ... Contamination detection part, 206 ... He-Cd laser light source, 208 ... Objective lens, 209 ... Detector

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[Procedure amendment]

[Submission date] June 28, 2002 (2002.6.2)
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Patent application title: Foreign object detection method and apparatus, and semiconductor device manufacturing method

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

3. Overheating the sample prior to heating the sample.
The sample is prepared by locally irradiating a laser different from the laser
Is locally overheated.
2. The foreign matter detection method described in 2.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

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[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign matter detection method and apparatus for detecting foreign matter and contamination existing on a substrate, or contaminant elements existing in the substrate with high accuracy, and a device therefor. The present invention relates to a semiconductor device manufacturing method for manufacturing a semiconductor device by arranging the device in a predetermined line.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

An object of the present invention is to provide a foreign matter detection method and apparatus capable of detecting foreign matter and contamination existing on a substrate with high accuracy.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Another object of the present invention is to provide a semiconductor manufacturing line in which the degree of contamination of a substrate to be processed and the presence or absence of foreign matter can be easily detected in each vacuum processing apparatus for semiconductor manufacturing. Especially.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0009

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Claims (2)

[Claims] 1. In a semiconductor manufacturing line having a plurality of processing steps for processing a substrate, the substrate is heated in a low-pressure atmosphere before and after processing in the processing step for processing the substrate, respectively. The foreign matter or contamination of the substrate is detected while emphasizing the defects of the substrate, and the state of occurrence of the foreign matter or contamination on the substrate in the processing step is monitored using the detected foreign matter or contamination data. A method of manufacturing a semiconductor device, comprising: 2. A vacuum chamber means having a window for transmitting light, the inside of which is maintained in a low pressure state, a mounting means for mounting a sample in the vacuum chamber means, and a mounting means mounted on the mounting means. Heating means for heating the sample, laser irradiation means for scanning and irradiating a laser on the surface of the sample placed on the placing means through the window and heated by the heating means, and the laser Detecting means for detecting scattered light from the surface of the sample due to irradiation, and processing for processing the signal obtained by detecting the scattered light by the detecting means to obtain information on the state of occurrence of foreign matter or contamination on the sample And a means for detecting foreign matter.