JP2008298696A - Inspection method and inspection device of foreign matter on wafer circumferential edge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method and an inspection device of foreign matter on a wafer circumferential edge capable of accurately and quantitatively detecting foreign matter attached on the wafer circumferential edge. <P>SOLUTION: In the inspection method of the foreign matter on the wafer circumferential edge, light is irradiated from a floodlighting system on the wafer circumferential edge, and scattered light from the wafer circumferential edge is detected by a light receiving system to inspect the attached foreign matter and/or a defect on the wafer circumferential edge from intensity of the detected scattered light. A spot shape of the light at the wafer circumferential edge is formed to be elongate than a length of an apex in a length direction of the apex at the wafer circumferential edge. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention irradiates an inspection object such as a semiconductor wafer with light and inspects the inspection object for abnormalities (small foreign objects or defects adhering to the wafer) from the intensity of scattered light generated on the inspection object at this time In particular, the present invention relates to a method and apparatus for inspecting foreign matter at the peripheral edge of an object to be inspected.

  In the semiconductor manufacturing process, all chips formed on a wafer are processed under the same process conditions and chemical environment to form an integrated circuit. The yield of chips at the peripheral edge of the wafer (hereinafter referred to as the wafer edge) is formed. Is known to be considerably worse than near the wafer center. There are various factors that decrease the yield at the wafer edge. As one of the major factors, peeling or chipping of a thin film at the wafer edge and adhesion of fine foreign matters can be considered.

  As shown in FIG. 8A, the normal wafer edge is gradually inclined from the surface of the wafer (beveled) and cut off. The chamfered portion of the wafer edge is called a bevel, and the vertical portion is called an apex (also called apex). The shape of the wafer edge shown in FIG. 8A is called a bullet type, and the shape shown in FIG. 8B is called a round type.

  As a method of inspecting whether or not edge defects such as cracks, chips or scratches have occurred on the wafer edge, or whether fine foreign matter has adhered to the wafer edge, visual inspection using a penlight or the like is used. Other inspection methods include (1) image processing using a CCD camera and a computer, and (2) two inspection methods of irradiating a wafer edge with a line scan laser and detecting scattered light therefrom with a photodetector. Is representative.

  As an inspection method by image processing using a CCD camera and a computer, a method using a plurality of imaging cameras provided with a support portion that supports the wafer in a rotatable state and continuously images the peripheral edge of the supported wafer. (Patent Document 1). In this method, a peripheral edge of a wafer is imaged by a plurality of imaging cameras, and image processing is performed to inspect whether there is an abnormality in the wafer edge. However, in this method, since a plurality of imaging cameras are provided, there is a problem that the wafer inspection apparatus becomes large and the manufacturing cost of the wafer inspection apparatus itself increases.

  In order to solve the above-mentioned problems, a wafer edge inspection apparatus is disclosed in which a guide rail is provided in an arc shape around a wafer edge imaged by a camera, and the imaging camera is moved along the guide rail extending in the arc shape to image the wafer edge. (Patent Document 2). However, the wafer edge inspection method using a CCD camera is limited in detecting fine foreign substances because its performance depends on the imaging resolution of the CCD camera and the curvature and shape of the wafer edge. In addition, even if it is not a problem on a flat surface, there is a problem that a bent part such as a wafer edge blurs out of focus and it is difficult to identify a defect or a foreign substance attached thereto. Furthermore, it takes time to image all the parts and a large-capacity memory is required.

On the other hand, the method of irradiating the surface of a semiconductor wafer with laser light, generating scattered light on the surface of the semiconductor wafer, and detecting this scattered light with a photodetector is a problem of the depth of focus like the imaging method using a CCD camera. Less is.
As a method of inspecting for abnormalities at the wafer edge using laser light irradiation and scattered light, the laser light is focused on the wafer edge, laser light is irradiated, the periphery of the wafer edge is scanned, and the resulting scattered light is collected using an elliptical mirror. A method and apparatus for inspecting wafer edge defects and foreign matter adherence by analyzing the intensity of scattered and scattered light and frequency analysis is disclosed (Patent Document 3).

However, in the inspection method using the elliptical mirror disclosed in Patent Document 3, since the laser light source and the light receiver are fixed, it cannot be identified whether the wafer edge portion is abnormal in the apex portion or the bevel portion. There's a problem. In addition, since the laser beam is not irradiated perpendicularly to the wafer edge, it is necessary to use an elliptical mirror to collect the scattered light, and there is a problem that the apparatus becomes large. Further, in order to identify whether there is an abnormality in the apex portion of the wafer edge or the bevel portion, a plurality of apparatuses are installed as in Patent Document 1, or a rotation mechanism is provided as in Patent Document 2. There is a need.
However, even if it does so, since an elliptical mirror takes fixed width and volume, there exists a problem that an apparatus enlarges or a complicated rotation mechanism is needed. Furthermore, the method using an elliptical mirror generally has poor sensitivity. This is because the accuracy of the elliptical mirror directly becomes the measurement accuracy. Therefore, in order to increase the measurement accuracy, it is necessary to increase the accuracy of the elliptical mirror and there is a problem that the cost increases.

JP 2003-243465 A JP 2006-294969 A Japanese Patent No. 2999712

  As described above, when inspecting the presence or absence of an abnormality of the wafer edge, it is accurately determined which part of the wafer edge has a size of a defect and how much foreign matter is attached to which part. Moreover, it is necessary to obtain the data as quantified with high reliability. Further, it is desirable that the inspection can be completed in a short time, and that the inspection apparatus is simple and low cost.

  According to the knowledge of the present inventors, a high stress region is created in the bevel portion and apex portion of the wafer edge, and thin film peeling is likely to occur, and the bevel portion of the wafer edge is covered by a wafer transfer robot or other mechanical contact. It is clear that the thin film is chipped and particles are attached.

  In addition, defects (defects, cracks, etc.) generated on the wafer edge in this way and foreign matters such as chips adhering to the wafer irradiate the laser beam at a predetermined angle with respect to the wafer edge surface, and the scattered light. It is clear that the wafer edge abnormality can be detected with extremely high sensitivity if the light is received by a predetermined light receiving system. In addition, it is known that how much anomaly is in which part of the wafer edge can be easily detected by irradiating laser light formed into a predetermined spot shape for each apex part and bevel part constituting the wafer edge. It was.

  Accordingly, an object of the present invention is to accurately and quantitatively detect which part of a wafer edge has a defect of which size and how much foreign matter is attached to which part. A foreign matter inspection method and a wafer edge foreign matter inspection apparatus are provided.

  The present invention irradiates light to the peripheral edge of the wafer by the light projecting system, detects scattered light from the peripheral edge of the wafer by the light receiving system, and detects foreign matter and / or defects attached to the peripheral edge of the wafer from the intensity of the detected scattered light. In the foreign matter inspection method at the wafer peripheral edge, the light spot shape at the wafer peripheral edge is formed to be longer than the apex length in the length direction of the apex at the wafer peripheral edge. .

  By making the shape of the light irradiated to the peripheral edge of the wafer longer than the length of the apex, the inspection of a predetermined apex portion can be completed with one light irradiation. This makes it possible to complete the inspection of the apex portion in a short time compared to the conventional scanning and inspection of the apex portion.

  It is preferable that the spot shape of the light is formed longer than the length of the bevel at the peripheral edge of the wafer. Thereby, the test | inspection of a predetermined bevel part can be completed by one light irradiation.

  Further, it is preferable that the spot shape of the light is formed to be longer than the apex at the peripheral edge of the wafer and longer than the bevel. Thereby, the apex portion and the bevel portion can be inspected with the same spot shape of light.

  In the wafer edge foreign matter inspection method of the present invention, the entire periphery of the apex portion of the wafer edge is inspected in a short time by irradiating the apex portion with light having a spot shape that is longer than the apex length while rotating the wafer. Can do.

  Further, by forming the light spot shape into a shape that is longer than the length of the bevel and inspecting the bevel portion while rotating the wafer, the entire circumference of the bevel portion of the wafer edge can be inspected in a short time.

  Further, by forming the light spot shape to be longer than the apex length and longer than the bevel length, the light spot shape in the apex portion inspection and the light spot shape in the bevel portion inspection are changed. Therefore, the wafer edge can be inspected.

  Of the scattered light of the light irradiated to the peripheral edge of the wafer, it is preferable to block the scattered light (direct scattered light from the wafer) not due to the foreign matter and / or defects. When light is irradiated to the wafer peripheral edge, reflected light directly reflected from the wafer peripheral edge enters the light receiving system in addition to the scattered light caused by foreign matter or the like adhering to the wafer peripheral edge. It is preferable to measure the intensity of scattered light after shielding such light.

In the wafer edge foreign matter inspection method of the present invention, since the light spot shape is configured as described above, for example, even if the wafer is slightly swung up and down and left and right, a portion that is not measured does not occur. On the other hand, a portion to be inspected overlaps at the time of apex measurement and at the time of bevel measurement, but as described in the embodiment, foreign matters other than the measurement portion can be ignored by setting the threshold value. For example, when measuring an apex, foreign matter in the bevel portion is ignored, and when measuring the bevel, foreign matter in the apex portion is ignored.
It is preferable to prevent vibration such as vertical movement of the wafer when the wafer is rotated.

  While rotating the wafer, for example, irradiate light in the order of the front surface bevel, apex, and back surface bevel at the wafer peripheral edge, inspect the entire periphery of the wafer peripheral edge, and the length of the apex at the wafer peripheral edge, Or foreign matter adhering to the entire surface of the wafer including the peripheral edge of the wafer by scanning the entire surface of the front and back surfaces of the wafer with a light spot shape that is formed to be longer than the longer one of the bevel lengths, and / or Or the defect can be inspected.

  The light is preferably a laser beam.

  According to the second aspect of the present invention, a light projecting system for irradiating light to the peripheral edge of the wafer, a light receiving system for receiving scattered light from the peripheral edge of the wafer, and foreign matter at the peripheral edge of the wafer from the intensity of the received scattered light. In the foreign matter inspection apparatus including the detecting means, the spot shape of the irradiated light at the peripheral edge of the wafer is formed to be longer than the apex length of the peripheral edge of the wafer or the length of the bevel. It is characterized by comprising a light shaping means.

  By providing light shaping means for shaping the light irradiating the peripheral edge of the wafer to be longer than the apex length and longer than the bevel length of the wafer peripheral edge, any of the apex part and the bevel part is provided. In addition, the inspection of the predetermined apex portion and the bevel portion can be completed by irradiating light once.

  A base on which the light projecting system and the light receiving system are fixed, base moving means for moving the base up and down, left and right, and back and forth with respect to the wafer, and a predetermined point on the wafer As a point, it is preferable to include a base rotating means for rotating the base.

  Thereby, it is possible to inspect from the front-side bevel to the apex and the back-side bevel at the peripheral edge of the wafer by a pair of light projecting system and light receiving system. Here, rotating the base around a predetermined point on the wafer means, for example, moving the base in an arc shape with the center of the apex as the center point, thereby tilting the base to a desired angle. be able to. As a result, it is possible to inspect the front and back bevels.

  It is preferable that the apparatus further includes means for rotating the wafer.

  It is preferable that the light receiving system includes means for shielding reflected light that does not originate from foreign matters and / or defects at the wafer peripheral edge out of the scattered light irradiated to the wafer peripheral edge. As a result, only the scattered light from the defect at the wafer peripheral edge or the foreign matter can be received, and the foreign matter at the wafer edge can be inspected with high accuracy.

  According to the present invention, it is possible to detect at high speed and accurately which portion of the wafer edge portion has what size defect and how much foreign matter is attached to which portion. Further, according to the present invention, a low-cost and high-performance wafer edge foreign matter inspection apparatus can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail based on examples. FIG. 1 is a conceptual diagram of a foreign substance inspection apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a spot shape at the wafer edge of the laser beam 13 when the laser beam 13 is irradiated from the light projecting system 11 to the wafer edge. In FIG. 2, the spot shape of the laser beam 13 is formed to be longer than both the apex length (vertical length) and the bevel length.

  The wafer 10 shown in FIG. 1 is placed on the wafer placement table 50 as shown in FIG. 3, and the wafer placement table 50 is rotated at a predetermined speed by the rotation mechanism provided in the support table 20 together with the wafer 10. While the wafer 10 is rotated by such a rotating mechanism, the light projection system 11 irradiates the laser beam 13. In this embodiment, a solid-state semiconductor laser is used as the light projecting system, but the present invention is not particularly limited to this, and any of a liquid laser, a gas laser, and a semiconductor laser may be used.

  Although the silicon photodiode is used for the light receiving system 12 (sensor for receiving the scattered light 14) in this embodiment, the present invention is not limited to this. For example, a photomultiplier tube, a phototransistor, a CCD device, an image Any of a sensor etc. may be sufficient.

  Conventionally, in a foreign matter inspection apparatus using a laser light source, as shown in FIG. 9, the focus of the laser beam 13 is focused on the wafer edge, and the spot shape of the laser beam on the wafer edge is irradiated as a point. The inspection is performed by scanning the part. That is, the wafer 10 is rotated, for example, the laser beam is scanned sequentially from the upper part of the apex toward the lower part, the scattered light 14 generated thereby is received by the light receiving system 12, and the intensity of the received scattered light 14 is determined from the intensity of the received scattered light 14. Checking for abnormalities.

  On the other hand, the present invention is characterized in that the spot shape of the laser beam 13 is formed to be narrower than both the apex length (vertical length) and the bevel length, as shown in FIG. Yes, the light projecting system 11 includes means for shaping the spot shape at the wafer edge of the laser light 13 irradiated from here.

  As shown in FIG. 2, the light projecting system 11 includes a lens 1 and a lens 2 therein, and controls the distance between the laser beam 13 and the lens 1 and the distance between the lens 2 and the wafer 10 to obtain a desired value. A mechanism (not shown) capable of forming laser light into a spot shape is provided.

  As shown in FIG. 2, the spot shape at the wafer edge of the laser beam 13 emitted from the light projecting system 11 is preferably a shape that is longer than the length of the apex in the vertical direction. For example, if the apex length is 0.3 mm, the length is preferably about 0.5 mm. That is, it is sufficient to protrude about 0.1 mm from both ends of the apex. Such a protrusion length is not limited to 0.1 mm on one side, but it has been found that 0.1 to 0.2 mm or a range of 10 to 30% of the apex length is suitable. As shown in FIG. 8, since the wafer edge has various shapes such as a bullet (round) type and a round type, when the apex length cannot be strictly defined, the wafer thickness is set to the laser beam thickness. It may be the length of the spot shape.

  The feature of the present invention is that, as shown in FIG. 2, the inspection of a predetermined apex portion can be completed by one irradiation of the laser beam 13 without scanning the apex portion with the laser beam 13. It is in. Similarly, the bevel portion can be completed by inspecting the predetermined bevel portion by irradiating the bevel portion with the laser beam 13 once.

  The irradiation angle of the laser beam 13 with respect to the wafer edge is not particularly limited. For example, the irradiation may be performed at an angle of 60 to 80 degrees with respect to the normal line at the laser beam irradiation point of the wafer edge.

  In FIG. 1, the light receiving system 12 preferably includes a mask for shielding light reflected from the wafer edge (light other than light scattered by a wafer edge defect or foreign matter). For example, when the light receiving system 12 is installed so that the reflected light enters from the center of the light receiving system 12, a predetermined mask may be provided at the center. Of course, when the position of the light receiving system 12 is adjusted so that the reflected light enters the end of the light receiving system 12, a mask may be provided at the end of the light receiving system 12.

  The light receiving system 12 receives the scattered light 14, photoelectrically converts and amplifies it, and outputs the scattered light signal as an electrical signal. The scattered photoelectric signal is amplified by the amplifier circuit 100 and then sent to the comparator 101 to specify the size of the foreign matter and further sent to the analysis device 102 to specify the location and the like of the foreign matter and then stored in the memory as data. Remembered.

  FIG. 3 is a schematic diagram of the overall configuration of the foreign matter inspection apparatus 1 of the present invention. The mounting table 50 on which the wafer 10 is mounted is supported by the support table 20. A wafer rotating mechanism for rotating the mounting table 50 is built in the support table 20. By this mechanism, the wafer 10 rotates at a predetermined speed.

  The rotation speed of the wafer 10 is adjusted to a predetermined speed by a rotation speed control device (not shown). Since the wafer edge inspection time depends on the rotation speed of the wafer 10, it is necessary to control the rotation at an optimal rotation speed in relation to the detection of the scattered light 14 in the light receiving system 12 and the subsequent processing. In general, a speed of about 1 m / sec is a standard for a wafer having a diameter of 300 mm.

  The light projecting system 11 and the light receiving system 12 are fixed on the base 15. The base 15 is fixed to the rotary arm 17, and is configured to rotate about 16 by the rotary arm 17. Further, the base 15 is configured to move up and down with respect to the wafer 10 by the guide plate 30 and also to move back and forth with respect to the wafer 10 by the guide plate control mechanism 40. By configuring the base 15 to rotate, move up and down, and back and forth in this way, foreign matter adhering to the front surface, front surface bevel, apex, back surface bevel, and back surface of the wafer 10 can be detected.

  FIG. 4 is a diagram showing details of the rotation mechanism of the base 15. The rotating arm 17 is fixed to the guide plate 30. A light projecting system 11 and a light receiving system 12 are fixed to the base 15. The base 15 is moved in an arc shape with the center of the apex of the wafer edge as a center point by the rotating arm 17. As the base 15 moves in an arc shape, the base 15 tilts so as to look into the wafer 10 from above or below. Thereby, both the front surface side bevel part and the back surface side bevel part of the edge of the wafer 10 can be inspected.

  In starting the edge inspection of the wafer 10, the wafer 10 is rotated, the height of the wafer 10 and the height of the base 15 (Y-axis direction) are adjusted by the guide plate control mechanism 40, and then the wafer 10 The base 15 is brought close to face the edge. Then, the base 15 is moved by the rotating arm 17, the bevel portion on the wafer surface side is inspected from above the wafer edge, the base 15 is then leveled by the rotating arm 17, and the apex portion is inspected from the horizontal direction. Then, the base 15 is moved again by the rotating arm 17, and the bevel portion on the wafer rear surface side is inspected from the lower direction, thereby completing the inspection of the entire circumference of the wafer edge.

  FIG. 5 is a photoelectric conversion circuit diagram for converting the intensity of the scattered light 14 received by the light receiving system 12 into an electric signal. The light receiving system 12 photoelectrically converts the scattered light 14 and outputs a scattered light signal Q corresponding to the intensity of the scattered light 14. The scattered light signal Q is amplified by the amplifier circuit 100. The analog signal output from here is compared with the reference voltage by the comparator 101, and the size of the foreign matter is specified. The result of conversion into a digital signal for each particle size and data such as the rotation speed and scattered light intensity of the wafer 10 are sent to the analysis device 102, and the analysis device 102 identifies the location of the particle, defect, etc. attached to the wafer edge. Is done.

Infrared semiconductor laser (transmitting wavelength is 785 nm, low threshold current is 30 mA) is used as light source of light projecting system 11, and silicon PIN photodiode (sensitivity wavelength range: 320 nm to 1060 nm) is used as light receiving system 12, and wafer edge inspection is performed. It was.
A wafer having a diameter of 300 mm was used as a test body. The shape of the peripheral edge of this wafer is a bullet type, the apex length is about 0.3 mm, and the bevel length is also about 0.3 mm. The spot shape at the wafer edge of the laser beam was an elongated shape having a length of 32 nm and a maximum width of 0.8 mm. While rotating the wafer at a speed of 1 m / sec, the apex portion was irradiated with laser light, and the intensity of the scattered light obtained thereby was photoelectrically converted. FIG. 6 is a graph showing the results.

  The vertical axis in FIG. 6 is voltage, which represents the intensity of scattered light. The horizontal axis indicates the position of the wafer edge (where it is on the entire circumference of the wafer). This position can be determined from the rotation speed of the wafer.

  As is apparent from FIG. 6, when there is an abnormality in the apex portion, strong scattered light is emitted from the abnormal portion. On the other hand, even if there is a similar size abnormality in the beveled portion, the intensity of the scattered light in the beveled portion is weak. For this reason, for example, if the threshold value of the output of the light receiving system 12 is set to 2 V, the output signal of the scattered light from the bevel portion is erased, and only the abnormality of the apex portion is obtained.

  FIG. 7 is a graph showing the relationship between the size of foreign matter (particle size) and the output voltage value in the present embodiment, and is a so-called calibration curve. By comparing this data with the output value from the amplifier circuit 100 by the comparator 101, the size of the particle can be estimated. For example, if the output voltage is 1V, it is determined that the particle is about 1 μm, and if it is 2V, the particle is about 2 μm.

It is a conceptual diagram which shows an example of the foreign material inspection apparatus of this invention. It is a figure which shows the spot shape of the laser beam in a wafer edge. It is the schematic which shows an example of the whole structure of the foreign material inspection apparatus of this invention. It is detail drawing of the rotation mechanism of a base. It is a photoelectric conversion circuit diagram which converts the intensity | strength of a scattered light into an electrical signal. It is a graph which shows the result of a present Example. The graph (calibration curve) which showed the relationship between the size of the foreign material and output voltage value in a present Example. It is a figure which shows the shape of a wafer edge. It is a figure which shows the foreign material inspection apparatus using the conventional laser light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foreign material inspection apparatus 10 Wafer 11 Light projection system 12 Light reception system 13 Laser light 14 Scattered light 15 Base 16 Center point 17 Rotating arm 20 Support base 30 Guide plate 40 Guide plate control mechanism 50 Mounting base 60 Base 100 Amplifier circuit 101 Comparator 102 Analysis device

Claims (12)

A wafer that irradiates the peripheral edge of the wafer with a light projecting system, detects scattered light from the peripheral edge of the wafer with a light receiving system, and inspects foreign matter and / or defects adhering to the peripheral edge of the wafer from the intensity of the detected scattered light In the foreign matter inspection method at the peripheral edge,
A method for inspecting a foreign substance at a wafer peripheral edge, wherein a spot shape of light at the peripheral edge of the wafer is formed to be longer than a length of the apex in a length direction of the apex at the peripheral edge of the wafer. A wafer that irradiates the peripheral edge of the wafer with a light projecting system, detects scattered light from the peripheral edge of the wafer with a light receiving system, and inspects foreign matter and / or defects adhering to the peripheral edge of the wafer from the intensity of the detected scattered light In the foreign matter inspection method at the peripheral edge,
A foreign matter inspection method for a wafer peripheral edge, wherein a spot shape of light at the peripheral edge of the wafer is formed to be longer than a length of the bevel in a length direction of the bevel at the peripheral edge of the wafer. In a foreign matter inspection method for a wafer peripheral edge in which light is irradiated to the wafer peripheral edge, scattered light from the wafer peripheral edge is detected, and foreign matter adhering to the wafer peripheral edge and / or defect is inspected from the intensity of the detected scattered light ,
A method for inspecting a foreign substance at a wafer peripheral edge, characterized in that the spot shape of light at the wafer peripheral edge is formed to be longer than the apex length of the wafer peripheral edge or the bevel length, whichever is longer. .   Inspection of foreign matter at the peripheral edge of the wafer, wherein the wafer bevel, apex, and backside bevel are sequentially irradiated with light while rotating the wafer to inspect the entire periphery of the wafer peripheral edge. Method.   5. The wafer peripheral edge according to claim 1, wherein, of the light received by the light receiving system, foreign matter adhering to the wafer peripheral edge and / or reflected light not caused by a defect is shielded. Foreign substance inspection method.   The whole surface of the peripheral edge of the wafer is inspected by the foreign matter inspection method according to claim 4, and the entire surface of the front and back surfaces of the wafer is scanned by the light spot shape according to claim 3 to adhere to the entire surface of the wafer. A method for inspecting foreign matter on a wafer, wherein foreign matter and / or defects are inspected.   6. The method for inspecting a foreign substance at a peripheral edge of a wafer according to claim 1, wherein the light is laser light. A light projecting system for irradiating light to the edge of the wafer;
A light receiving system for receiving scattered light from the peripheral edge of the wafer;
A foreign matter inspection apparatus comprising: means for detecting foreign matter at the peripheral edge of the wafer from the intensity of the scattered light received;
It comprises light shaping means for shaping the spot shape of the irradiated light at the peripheral edge of the wafer longer than the apex length of the wafer peripheral edge or the length of the bevel, whichever is longer. Foreign matter inspection device. A base on which the light projecting system and the light receiving system are fixed;
A base moving means for moving the base up and down, left and right, and back and forth with respect to the wafer;
The foreign matter inspection apparatus according to claim 8, further comprising: a base rotating unit that rotates the base around a predetermined point of the wafer.   10. The foreign matter inspection apparatus according to claim 8, further comprising means for rotating the wafer.   The light receiving system includes means for shielding reflected light that does not originate from foreign matters and / or defects at the wafer peripheral edge out of the scattered light irradiated to the wafer peripheral edge received by the light receiving system. Item 11. A foreign matter inspection apparatus according to any one of Items 8 to 10.   The foreign matter inspection apparatus according to claim 8, wherein the light is a laser beam.

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