JP2011085602A - Inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device for an object to be inspected which correctly determines the boundary between a planar region of a surface of the object to be inspected which is irradiated with a laser beam and a predetermined region which corresponds to an wafer edge. <P>SOLUTION: The inspection device includes: a laser light source 31 for transmitting a laser beam Lt and irradiating the surface of the object 1 to be inspected with it; a rotary table 21 on which the object 1 to be inspected is placed, and which rotates it; a moving mechanism 22 for moving the rotary table in the transfer direction of the object 1 to be inspected; a camera 500 for taking an image of a laser spot Sp of the laser beam Lt irradiated on the surface of the object 1 to be inspected, and an image of the periphery of the laser spot Sp; and a data processor 52 for obtaining the ranges of the flat planar region of the surface of the object to be inspected which is irradiated with the laser beam Lt and the wafer edge which is out of the planar region, using the images of the laser spot Sp and the periphery of the laser spot Sp. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inspection apparatus for an inspection object such as a wafer, and in particular, irradiates the surface of an inspection object such as a wafer with a laser beam to obtain a range of a wafer edge portion deviating from a flat planar region on the surface of the inspection object. The present invention relates to an inspection apparatus for an inspection object.

  As an example of an inspection apparatus for inspecting an inspection object such as a wafer, Japanese Patent Application Laid-Open No. 9-304289 discloses a technique of an inspection object inspection apparatus for inspecting the surface of a wafer of the inspection object.

  In the technique of the wafer surface inspection apparatus disclosed in Japanese Patent Laid-Open No. 9-304289, a laser beam output from a laser light source becomes a laser spot Sp (hereinafter referred to as a spot Sp) by a lens system. The image is projected perpendicularly or obliquely onto the surface of the wafer, and the entire surface of the wafer is scanned by scanning the surface of the wafer in a spiral shape according to the movement of the wafer.

  If there are foreign matter e, scratches, crystal defects (COP) or other defects on the surface of the wafer, the spot Sp output from the laser light source is scattered at a wide range of angles (directions) due to the foreign matter e or COP defects. Se is generated, and a part of the scattered light Se is collected by a condenser lens and received by a photomultiplier tube (hereinafter referred to as PMT) of a light receiver which is a photoelectric converter.

  The scattered light Se incident on the PMT is converted into an electrical signal here, and the number and size of the defects such as the foreign matter e and COP are obtained by processing the converted electrical signal (light reception signal). Foreign matter data indicating the position is generated, and the foreign matter e and the state of the defect are displayed as a map on a printer or a display (not shown).

  In the wafer surface inspection apparatus disclosed in Japanese Patent Application Laid-Open No. 2006-201179, as a technique for detecting defects near the edge of the wafer, when a laser beam is irradiated on the surface of the wafer, scattered light generated from the edge of the wafer is edged. Directivity of scattered light detected by a detector located in the tangential direction of the edge of the wafer, taking advantage of the fact that the directivity is strongly distributed in the normal direction but the scattered light generated from the defect is not noticeable. A technique for determining whether the light is scattered only from the edge portion of the wafer or scattered light including a defect portion is disclosed.

JP-A-9-304289 JP 2006-201179 A

  However, in the inspection technique described in Japanese Patent Application Laid-Open No. 2006-201179, when the entire surface of the wafer, which is an inspection object, is continuously inspected by irradiating a laser beam, the edge portion of the wafer is irradiated by laser beam irradiation. Because of the influence of strong diffracted light generated from the wafer, the receiver that detects scattered light generated from foreign matter and scratches on the wafer surface deteriorates in a relatively short period of time, and as a result, exists at the edge of the wafer. There is a problem that it becomes difficult to detect foreign matter and defects such as COP at the edge of the wafer because scattered light generated from defects such as foreign matter and COP cannot be detected accurately.

  Similarly, in the inspection technique described in Japanese Patent Application Laid-Open No. 9-304289, when the entire surface of the wafer, which is an object to be inspected, is continuously inspected by irradiating a laser beam, foreign matter and scratches on the surface of the wafer are detected. The received light signal received by the light receiver that detects the scattered light generated from the light is affected by strong diffracted light generated at the edge of the wafer, and the noise component becomes high, and from the foreign matter and defects such as COP existing on the wafer surface. Since the generated scattered light is buried in this noise component, there is a problem that it is difficult to accurately detect the presence or absence of a foreign matter or a defect such as a COP at the edge portion of the wafer.

  By the way, in the inspection technique using a laser beam as described in Japanese Patent Application Laid-Open No. 2006-201179 and Japanese Patent Application Laid-Open No. 9-304289, foreign matter and scratches on the surface of the wafer of the inspection object are irradiated by irradiating the laser beam. In the predetermined area adjacent to the planar area corresponding to the area to be inspected and corresponding to the edge area of the wafer, the strong diffracted light generated from the predetermined area is incident on the light receiver (PMT) that detects the scattered light as described above. As a result, the photoreceiver may be damaged, so that it is treated as a non-inspection area that is not irradiated with a laser beam for scanning a foreign object or a flaw.

  The predetermined area which is a non-inspection area in the inspection object is the surface of the wafer due to the eccentricity of the wafer itself to be measured by irradiating the inspection object with a laser beam or the outer diameter difference due to individual differences of the wafer. The size of the predetermined area is large or small.

  For this reason, when inspecting the surface of an object to be inspected by irradiating a laser beam, the area of the plane area to be inspected on the surface of the wafer of the object to be inspected is set as wide as possible, and this plane area is Although it is necessary to inspect by scanning, in order to inspect by setting the plane area of the wafer surface as wide as possible, the range of the predetermined area corresponding to the edge of the wafer is accurately determined, that is, It is desirable to accurately determine the boundary position between the planar area and a predetermined area adjacent to the planar area, and set the range of the predetermined area as small as possible for inspection.

  An object of the present invention is to make it possible to set the plane area to be inspected of the inspection object as wide as possible when inspecting the surface of the inspection object by irradiating a laser beam. An object of the present invention is to provide an inspection apparatus for an inspection object that accurately inspects and inspects a boundary position with a predetermined area corresponding to an edge portion of the inspection object adjacent to the area.

  The inspection apparatus of the present invention includes a laser light source that emits a laser beam to irradiate the surface of an object to be inspected, a rotary table that mounts and rotates the object to be inspected, and a direction in which the inspection table is transferred. A moving mechanism for moving the surface of the object to be inspected, a laser spot image of the laser beam irradiated on the surface of the object to be inspected, a camera for taking an image of the periphery of the laser spot, an image of the laser spot, and the periphery of the laser spot And a data processing device that obtains a flat plane area on the surface of the object to be inspected irradiated by the laser beam and a range of the wafer edge portion outside the plane area.

  According to the present invention, when inspecting the surface of an object to be inspected by irradiating a laser beam, in order to make it possible to set the range of the plane area to be inspected of the object to be inspected as wide as possible, It is possible to realize an inspection apparatus for an inspection object that accurately determines and inspects a boundary position with a predetermined area corresponding to an edge portion of the inspection object adjacent to the area.

FIG. 1A is a conceptual diagram showing the intensity of diffracted light generated at the edge of a wafer when a semiconductor wafer as an object to be inspected is irradiated with laser light. FIG. 1B is a partial side view of the diffracted light generated in the edge region of the wafer as viewed from the side, and FIG. 1C is the scattered light generated from the foreign matter adhering to the surface of the wafer. Explanatory drawing which showed the state of. FIG. 2 shows an outline of a photoreceiver constituting the inspection apparatus of the embodiment of the present invention shown in FIG. 3, FIG. 2 (a) is a top view showing an arrangement state of the photoreceiver, and FIG. 2 (b) is a wafer. Schematic which shows the content of the processing of the received light signal at the time of detecting the scattered light which arose on the surface of this with a light receiver. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified configuration diagram of a detection optical system constituting an inspection object inspection apparatus that is an embodiment of the present invention. FIG. 4 is an explanatory view showing the inspection state of the edge region of the wafer by the inspection apparatus of the embodiment of the present invention shown in FIG. 3, and FIG. 4A is a schematic diagram of the edge region of the wafer irradiated with the laser beam, FIG. 4 (b) is a diagram showing the intensity ratio of the noise component in the received light signal of the scattered light detected by the light receiver of the present embodiment, and FIG. 4 (c) is the intensity of the noise component shown in FIG. 4 (b). Explanatory drawing which showed the example of a setting screen of threshold value Th in a ratio screen. The flowchart which shows the procedure of the test | inspection of the wafer in the test | inspection apparatus of the Example of this invention shown in FIG. The simplified block diagram which shows the optical system which comprises the test | inspection apparatus of the to-be-measured object which is another Example of this invention. The simplified block diagram which shows the optical system which comprises the test | inspection apparatus of the to-be-measured object which is further another Example of this invention.

  An inspection apparatus for an inspection object that is an embodiment of the present invention will be described below with reference to the drawings.

  The inspection object to which the inspection apparatus for the inspection object according to the embodiment of the present invention is applied is, for example, a semiconductor wafer, a wafer-like object, or an insulator wafer (for example, a sapphire glass wafer, a quartz glass wafer, or the like).

  Then, the inspection method and inspection apparatus of the inspection object which is one embodiment of the present invention applied to the surface inspection of the semiconductor wafer as the inspection object will be described below.

  A silicon wafer as a material for a semiconductor IC is made of high-purity polycrystalline silicon. The silicon wafer is made into a single crystal silicon ingot by a pulling method, the single crystal silicon ingot is sliced into a thin plate, and the surface of the thin silicon wafer and the outer peripheral edge of the wafer are polished to a mirror finish.

  Further, the silicon wafer is manufactured by cleaning the foreign matter adhering to the surface of the thin silicon wafer.

  During the manufacturing process of these silicon wafers, there are cases where foreign matter adheres or cracks occur at the outer peripheral edge of the wafer.

  The adhesion of foreign matter on the outer peripheral edge of the wafer, and defects such as cracks, scratches, and COPs are highly likely to be fatal defects, especially in wafers with a large diameter (300 mm). There is a need for inspection.

  In an inspection apparatus for inspecting the surface of a wafer to be inspected, which is an inspection apparatus according to an embodiment of the present invention, the wafer surface is irradiated with a laser beam from the center to the outer periphery of the wafer, Scattered light scattered on the surface is received, and the wafer surface of the inspection object is inspected based on the received scattered light.

  By the way, in the wafer inspection system, the area where the noise signal is high due to the influence of strong diffracted light generated from the edge of the wafer due to laser beam irradiation at the outer periphery of the wafer surface is excluded from the inspection area on the wafer surface. The effect of noise is avoided.

  However, as described above, if the area where the noise signal is high due to the influence of diffracted light at the outer periphery of the wafer surface is excluded from the inspection area on the wafer surface, the area on the wafer surface where the noise is high due to the influence of diffracted light is removed. Since the scattered scattered light cannot be received, it becomes impossible to obtain information on the foreign matter adhering to the wafer surface in the region or the defect generated on the wafer surface.

  Therefore, in the inspection apparatus for an inspected object according to an embodiment of the present invention, a plurality of light receivers for detecting scattered light scattered on the wafer surface by the laser beam irradiated on the wafer surface are installed. Diffracted light generated at the edge of the wafer from multiple light receivers by taking advantage of the characteristic that the direction (azimuth) of the strong diffracted light generated from the edge of the wafer is always radiated in the same direction (direction). By selecting a light receiver placed at an angle (direction) that is not affected by light and receiving scattered light, information on foreign matter adhering to the wafer surface and defects generated on the wafer surface is obtained over the entire wafer surface. It is configured to be possible.

  In the inspection object inspection apparatus according to one embodiment of the present invention, a plurality of light receivers for detecting scattered light scattered on the surface of the wafer by the laser beam irradiated on the surface of the wafer are installed. Boundary position between the flat plane area of the surface of the object to be inspected irradiated by the laser beam and the predetermined area corresponding to the edge portion deviated from the plane area by performing arithmetic processing based on the received light signal of the scattered light received by the instrument It is configured to be able to discriminate.

  An inspection object inspection apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. First, FIG. 1 shows a semiconductor wafer 1 as an inspection object and a laser that irradiates the semiconductor wafer 1. Conceptual diagram showing the state of the beam Lt, the intensity of the diffracted light a generated at the edge portion d of the wafer 1 by the irradiation of the laser beam Lt, and the scattered light Se generated from the foreign matter on the surface of the wafer 1 by the irradiation of the laser beam Lt It is.

  1A is a top view showing strong diffracted light a and weak diffracted light b generated at the edge portion d of the wafer 1 from above, and FIG. 1B is strong diffracted light generated at the edge portion d of the wafer 1. FIG. 1C is a side view showing a from the side, and FIG. 1C is an explanatory view showing the state of the scattered light Se generated from the foreign substance e existing on the surface of the wafer 1.

  As shown in FIG. 1A, the laser beam c that forms the laser beam Lt is irradiated onto the surface of the wafer 1 having a radius r. When the laser beam c is irradiated, strong diffracted light a is generated in the diameter direction of the wafer 1 and weak (small) diffracted light b is generated in the tangential direction of the wafer 1 as shown in FIG.

  This intense diffracted light a is controlled such that the irradiation position of the laser beam c which is the laser beam Lt irradiated on the surface of the wafer 1 is constant, and the wafer 1 is scanned in the circumferential direction indicated by the arrow by scanning by the irradiation of the laser beam Lt. It always exists in the diameter direction of the wafer 1 in order to linearly move in a predetermined constant direction while rotating.

  Therefore, the strong diffracted light a is always formed in the same direction with respect to the light receiver described later. Due to the influence of the diffracted light a, the scattered light Se generated from the foreign matter e or defect (COP, scratch, crack, etc.) existing on the surface of the wafer 1 is buried in the noise due to the diffracted light a. It is difficult to obtain a desired detection signal.

  As shown in FIG. 1B, when the wafer 1 of the object to be inspected is irradiated with the laser beam Lt of the laser light c, the diffracted light a generated at the edge portion d of the wafer 1 is viewed from the side, and the laser light c Produces a strong diffracted light a at the outer peripheral edge in the radial direction of the wafer, which is the edge portion d of the wafer 1.

  Further, as shown in FIG. 1C, the laser beam Lt of the laser beam c becomes a laser spot Sp and is irradiated on the surface of the wafer 1, and the surface of the wafer 1 has defects such as foreign matter e and COP. When present, scattered light Se is generated at a wide range of angles (directions) from defects such as foreign matter e and COP.

  When the position of the laser spot Sp of the laser beam Lt irradiated on the surface of the wafer 1 is the edge portion d which is the end portion on the outer diameter side in the radial direction of the wafer 1, foreign matter is present in the edge region d on the surface of the wafer 1. As described above, when there is a defect such as e or COP, the scattered light Se generated from the defect such as the foreign substance e or COP is detected in the noise generated by the strong diffracted light a generated at the edge portion d of the wafer 1. The detection signal is buried and a desired detection signal of the scattered light Se cannot be obtained.

  Therefore, in the inspection object inspection apparatus according to the embodiment of the present invention, the influence of noise caused by the diffracted light a generated at the edge portion d of the wafer 1 is eliminated or reduced by the following configuration, and the foreign matter e on the surface of the wafer 1 is detected. Scattered light Se generated from defects such as COP and COP can be detected effectively.

  FIG. 3 is a simplified configuration diagram of a detection optical system that constitutes an inspection apparatus for an inspection object that is an embodiment of the present invention, and FIG. 2 is a light receiving structure that constitutes the inspection apparatus of the embodiment of the present invention shown in FIG. FIG. 2 (a) is a top view showing the arrangement of the light receivers, and FIG. 2 (b) is a light reception when scattered light generated on the wafer surface is detected by the light receiver. It is the schematic which shows the content of the process of a signal.

  The configuration of a wafer inspection apparatus for inspecting the surface of the wafer 1 as an inspection object according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG. High-angle light receivers 371 to 374 composed of photomultiplier tubes (PMT) or the like that detect scattered light, and low-angle light receivers 381 to 386 that also detect scattered light, respectively. An example of the arrangement viewed from above is shown.

  The high-angle light receivers 371 to 374 receive the scattered light Se that is incident on the surface of the wafer 1 as the scattered light Se that is scattered by defects such as foreign matter e and COP that exist on the surface of the wafer 1. It is a light receiver disposed along an angle of about 50 to 70 degrees from the surface.

  Similarly, the light receivers 381 to 386 for low angles are incident on the wafer 1 on which the laser beam Lt irradiated on the surface of the wafer 1 becomes scattered light Se scattered by a foreign matter e or a defect such as COP existing on the surface of the wafer 1. 1 is a light receiver disposed along an angle of about 20 to 40 ° from the surface of 1.

  FIG. 2B shows an example of the arrangement of the light receivers when the high angle light receivers 371 to 374 and the low angle light receivers 381 to 386 shown in FIG. 2A are viewed from the side. The four high-angle light receivers 371 to 374 are arranged in the circumferential direction so that the arrangement directions thereof are different from each other by 90 ° in the circumferential direction when viewed from above.

  In addition, when viewed from above, the low-angle light receivers 381 to 386 are arranged in the circumferential direction by varying the arrangement direction by 60 ° in the circumferential direction.

  Among these high-angle light receivers 371 to 374 and low-angle light receivers 381 to 386, strong diffracted light a in the diameter direction of the wafer 1 generated at the edge portion d of the wafer 1 by the irradiation of the laser beam. Receivers 372 and 374 for high angles arranged along the diameter direction of the wafer 1 are receivers that are greatly affected by diffracted light a. Light receivers 382 and 385, and light receivers 381 and 384 for low angles.

  The light receivers that are less affected by the strong diffracted light a are the high-angle light receivers 371 and 373 that are arranged perpendicular to the diameter direction of the wafer 1. The receivers are low-angle light receivers 383 and 386.

  Next, the configuration of the wafer surface inspection apparatus according to the present embodiment will be described. As shown in FIG. 3, as shown in FIG. 3, the rotary table 21 for mounting and rotating the wafer 1 and the rotary table 21 are moved in the transfer direction of the wafer 1. A linear movement mechanism 22, a light projecting optical system, and a data processing device 52 are provided, and a wafer 1 to be inspected as an inspection target is placed on the rotary table 21.

  The light projecting optical system disposed on the upper portion of the wafer 1 includes a laser light source 31 including a laser oscillator, and a laser beam Lt that is output from the laser light source 31 and irradiates the surface of the wafer 1 for scanning. Is reflected from the mirror 331 that is output from the laser light source 31 and constitutes the first light projecting optical system, and forms a laser spot Sp (hereinafter referred to as spot Sp) vertically downward to be perpendicular to the surface of the wafer 1. Projected (vertical illumination).

  In the second light projecting optical system constituting the light projecting optical system, the mirror 331 constituting the first light projecting optical system is indicated by a two-dot chain line from the optical path of the laser beam Lt output from the laser light source 31. The second light projecting optical system disposed on the extended line of the optical path traveled by the laser beam Lt is moved to a position above the vertical direction so that the laser beam Lt irradiated from the laser light source 31 travels. The laser beam Lt is reflected downward in the vertical direction by the mirror 332 that constitutes the laser beam, and the reflected laser beam Lt is reflected in the direction of the wafer 1 by another mirror 35 that constitutes the second light projecting optical system. A spot Sp is projected obliquely onto the surface of the wafer 1 (oblique irradiation).

  The laser spot Sp of the vertically irradiated laser beam Lt or the laser spot Sp of obliquely irradiated laser beam Lt is applied to the wafer 1 according to the movement of the wafer 1 by driving the rotary table 21 and the linear moving mechanism 22. Scan the surface.

  The wafer 1 rotates while being mounted on the rotary table 21 by driving the rotary table 21 and the linear moving mechanism 22, and the rotary table 21 is driven by the linear moving mechanism 22 according to the rotation speed of the rotary table 21. It is configured to move in the radial direction (X direction: white arrow direction in the figure).

  By configuring the first light projecting optical system and the second light projecting optical system as described above as the wafer surface inspection apparatus of this embodiment, the laser spot Sp irradiated on the surface of the wafer 1 The surface of the wafer 1 is spirally scanned from the center of the wafer 1 to the outer peripheral side in the radial direction. As a result, the surface of the wafer 1 can be scanned over the entire surface.

  The driving of the rotary table 21 and the linear movement mechanism 22 is controlled by the data processing device 52 via the drive controller 51.

  In the wafer surface inspection apparatus according to the present embodiment, as shown in FIG. 1C, when a foreign object e or a defect exists on the surface of the wafer 1, the laser spot Sp of the laser beam Lt has a wide range due to the foreign object e or the defect. Scattered light Se is generated at an angle (direction).

  As shown in FIG. 2B, the scattered light Se scattered at a wide range of angles (directions) due to foreign matter e and defects existing on the surface of the wafer 1 is condensed and photoelectrically reflected. Light is received by high-angle light receivers 371 to 374 and low-angle light receivers 381 to 386, each of which includes a photomultiplier tube (hereinafter referred to as PMT), which is a converter.

  Scattered light Se scattered from a defect such as foreign matter e or COP existing on the surface of the wafer 1 incident on the high-angle light receivers 371 to 374 and the low-angle light receivers 381 to 386 is reflected on the light receivers 371 to 371. 374 and the light receivers 381 to 386 are respectively converted into light reception signals, and the converted light reception signals (electrical signals) are input to the foreign object detector 4.

  The received light signal input to the foreign object detector 4 is sent from the foreign object detector 4 to the data processing device 52, and in this data processing device 52, an A / D conversion circuit (A / D) provided in the data processing device 52. After being converted into digital data by 71, it is temporarily stored as digital data in a memory 72 provided in the data processing device 52.

  Further, by executing a predetermined program by an arithmetic unit (MPU) 73 provided in the data processing device 52, the high angle light receivers 371 to 374 converted into the digital data once recorded in the memory 72, and The detection data of each received light signal received by the low-angle light receivers 381 to 386 is input from the movement amount of the linear movement mechanism 22, and the scanning position of the laser spot Sp of the laser beam Lt that scans the surface of the wafer 1 ( Data processing is performed by the calculation unit (MPU) 73 of the data processing device 52 together with the position data of the (detection position).

  As a result of performing the data processing by the arithmetic unit (MPU) 73 of the data processing device 52, the size of the defect such as the foreign matter e or COP existing on the surface of the wafer 1 is determined according to the detection data of the light reception signal. Further, the number of defects such as foreign matter e and COP is counted.

  Further, when the arithmetic unit (MPU) 73 of the data processing device 52 executes a predetermined program, the number and size of defects such as foreign matter e and COP existing on the surface of the wafer 1, and the position of the foreign matter e and the defect are detected. Is generated and output to the printer or the display 75, and the state of the foreign matter or defect is displayed as a map.

  2A and 3, high-angle light receivers 371 to 374 and low-angle light receivers 381 to 386 made of photomultiplier tubes (PMT) or the like are respectively disposed above the surface of the wafer 1. Although the situation is shown, the six light receivers 381 to 386 constituting the group of the low angle light receivers 381 to 386 are arranged in the circumferential direction with an angle of approximately 60 degrees. .

  The four light receivers 371 to 374 constituting the group of the high angle light receivers 371 to 374 disposed above the low angle light receivers 381 to 386 are each approximately 90 degrees. Are arranged in the circumferential direction at an angle of.

  Among the high-angle light receivers 371 to 374, the light receiver 372 and the light receiver 374 correspond to the diameter direction of the wafer 1 that is the object to be inspected (corresponding to the edge portion d of the wafer 1 when irradiated with the laser beam Lt). (A direction in which strong diffracted light a is generated in a predetermined region), the surface of the wafer 1 is arranged on the same line or a parallel line when viewed from above.

  In addition, the light receiver 371 and the light receiver 373 are on the same line as viewed from above the surface of the wafer 1 with respect to the tangential direction of the wafer 1 that is the object to be inspected (the direction in which strong diffracted light a is not generated in a predetermined region). They are arranged on a parallel line, that is, in a direction orthogonal to the arrangement direction of the light receivers 372 and 374.

  Next, an inspection state of a predetermined area corresponding to the edge portion d of the wafer 1 by the inspection apparatus according to the embodiment of the present invention shown in FIG. 3 will be described with reference to FIG.

  4A is a schematic diagram showing a region near the edge portion d of the wafer 1 that is irradiated with the laser beam Lt, and FIG. 4B is a diagram illustrating a high angle light receivers 371 to 374 and a low angle receiver. FIG. 4C shows an example of the threshold value setting screen on the apparatus screen, showing the intensity ratio of the noise components of the received light signals detected by the light receivers 381 to 386 of FIG.

  First, the definition of the predetermined region corresponding to the edge portion d on the surface of the wafer 1 will be described with reference to FIG. 4A. The peripheral portion of the laser spot Sp of the laser beam Lt irradiated on the surface of the wafer 1 is When reaching a portion Ep that starts to be inclined toward the radially outer end of the wafer 1 from a plane region that forms most of the surface of the wafer 1, the diffracted light a in the diameter direction of the wafer 1 generated by irradiation with the laser beam Lt The intensity suddenly increases, and the detection of the scattered light Se generated by the foreign matter e or the defect existing on the Ep portion on the surface of the wafer 1 starts to appear.

  Therefore, as described above, the predetermined region 10 corresponding to the edge portion d of the wafer 1 or the bevel from the portion Ep where the above-described inclination where the diffracted light a on the surface of the wafer 1 is increased to the radially outer end portion of the wafer 1 Define.

  In this case, a portion Ep at which the above-described inclination that becomes the boundary between the planar region that forms most of the surface of the wafer 1 and the predetermined region 10 is the boundary position Ep between the planar region and the predetermined region 10.

  As shown in FIG. 1A, weak diffracted light in the tangential direction of the wafer 1 generated by irradiating the laser beam Lt to the predetermined region 10 or the bevel corresponding to the edge portion d of the surface of the wafer 1. Compared with the strong diffracted light a generated in the diameter direction of the wafer 1, b does not significantly affect the detection of the scattered light Se generated by the foreign matter e or a defect.

  Scanning of the surface of the wafer 1 by the laser spot Sp of the laser beam Lt irradiated on the surface of the wafer 1 extends beyond the boundary position Ep from a planar region that forms most of the surface of the wafer 1 that is the inspection object. When the predetermined region 10 is applied, the high-angle light receivers (371, 373) and the low-angle light receivers (383, 386) arranged at an angle that does not receive diffracted light (or is less affected by diffracted light). ) And a high-angle light receiver (372, 374) and a low-angle light receiver (381, 382, 384, 385) arranged at an angle that receives the diffracted light (or is greatly influenced by the diffracted light). In the meantime, a large difference appears in the noise level due to the diffracted light mixed in the received light signal for detecting the scattered light Se generated from the defect such as the foreign matter e or COP existing on the surface of the wafer 1.

  FIG. 4B shows a light receiver that is arranged at an angle that does not receive diffracted light (or that is less affected by diffracted light) and a light receiver that is arranged at an angle that receives diffracted light (or where the influence of diffracted light is large). Then, the scattered light Se generated from the defect such as the foreign matter e or COP is received, and the diffracted light is received by the foreign matter detector 4 shown in FIGS. 2B and 3 (or the influence of the diffracted light). The ratio of the output voltage V1 output from the light receiver arranged at an angle (large) and the output voltage V2 output from the light receiver arranged at an angle not receiving diffracted light (or having little influence of diffracted light). The calculated output voltage ratio (V1 / V2) is shown together with the threshold Th.

  Here, the output voltage output from the light receiver arranged at an angle that does not receive the diffracted light (or is less influenced by the diffracted light) is V2, and is arranged at an angle that receives the diffracted light (or has a large influence on the diffracted light). The output voltage output from the light receiver is V1.

  In FIG. 4B, the ratio of the output voltage V1 and the output voltage V2 detected by the light receiver (V1 / V2) is plotted on the vertical axis from the center of the surface of the wafer 1 having the radius R to the radially outer end. The abscissa is the distance R, and the intensity ratio of the noise components in the received light signal of the scattered light calculated by the foreign object detector 4 is shown as the value of the output voltage ratio V1 / V2 together with the threshold Th.

  From the value of the output voltage ratio V1 / V2 shown in FIG. 4B, the position of the surface of the wafer 1 irradiated with the laser spot Sp of the scanning laser beam Lt is in the radial direction of the wafer 1 from the plane region. When reaching a predetermined region 10 corresponding to the edge portion d of the outer end portion of the light, strong diffracted light a as shown in FIG. 1A is generated and affected by the strong diffracted light a (or diffracted). Since the value of the output voltage ratio suddenly increases (because of the influence of light), the value of the ratio V1 / V2 of the output voltage is compared with a threshold value to compare the planar area of the wafer 1 and the radial direction of the wafer 1 It is possible to accurately determine the boundary position Ep between the predetermined region 10 corresponding to the edge portion d of the outer end portion.

  Therefore, as an inspection condition of the wafer 1 that scans the surface of the wafer 1 by irradiating the laser spot Sp of the laser beam Lt, the value of the output voltage ratio V1 / V2 is just as illustrated in FIG. If the threshold value Th to be compared can be arbitrarily set, the ratio V1 / V2 of the output voltages detected by the light receiver shown in FIG. Is determined to be the boundary position Ep between the planar area and the predetermined area 10, and the entire area exceeding the threshold Th corresponds to the edge portion d on the surface of the wafer 1. It can be determined as the predetermined area 10.

  As described above, the arithmetic operation unit 73 of the data processing device 52 performs the comparison operation based on the light reception signal received by the detector, thereby accurately determining the boundary position Ep between the planar region on the surface of the wafer 1 and the predetermined region 10. It becomes possible to judge.

  As a result, the range over which the surface of the wafer 1 is scanned can be set to a wide range in which the effective range as the planar area of the wafer 1 to be scanned by irradiating the laser spot Sp of the laser beam Lt is extended to the limit with high accuracy.

  Further, as described above, the range of the predetermined region 10 on the surface of the wafer 1 can be accurately set by performing a comparison operation with the calculator 73 of the data processing device 52 based on the received light signal received by the detector. When scanning is performed by irradiating the laser spot Sp of the laser beam Lt 10 with a laser beam, it is possible to select a light receiving signal by selecting a light receiving device that is not affected by the diffracted light or at a position having little influence.

  As a result, it is possible to measure the state of defects such as foreign matter e and COP existing in the predetermined region 10 without being affected by the diffracted light or with less influence.

  That is, when a predetermined region 10 corresponding to the edge portion d of the wafer 1 is irradiated with the laser spot Sp of the laser beam Lt and the presence or absence of a defect such as a foreign substance e or COP existing in the predetermined region 10 is measured, From the above-described high-angle light receivers 371 to 374 and low-angle light receivers 381 to 386 by the sorting process in the arithmetic unit 73 of the data processing apparatus 52 provided in the wafer surface inspection apparatus of the embodiment, High-angle light receivers 371 and 373 and low-angle light receivers 383 that are arranged at angles that do not receive strong diffracted light a generated at the edge portion d of the surface of the wafer 1 (or that are less affected by diffracted light), 386 is selected, and the scattered light e generated from a defect such as a foreign substance e or a COP existing in a predetermined region 10 on the surface of the wafer 1 is measured based on a light reception signal detected by each selected light receiver. Thus, a defect such as foreign matter e or COP existing in a predetermined region 10 on the surface of the wafer 1 without being affected by (or reducing the influence of) noise due to the strong diffracted light a generated in the edge region d of the wafer 1. It is possible to accurately measure the situation.

  Alternatively, strong diffracted light generated in the edge region d from the high angle light receivers 371 to 374 and the low angle light receivers 381 to 386 by the selection process and sensitivity correction process by the arithmetic unit 73 of the data processing device 52. selected by selecting the high-angle light receivers 372 and 374 (or the low-angle light receivers 381 and 384 and the light receivers 382 and 385) arranged at an angle that receives a (or is greatly influenced by diffracted light) An operation of a sensitivity correction process for lowering the light receiving sensitivity of the light receiver is performed, or the intensity of the laser beam Lt irradiated on the surface of the wafer 1 is lowered for irradiation.

  Then, based on the light reception signal detected by the selected light receiver that has been modified to reduce the sensitivity, or the light reception signal detected by the light receiver by the scattered light from the laser beam Lt irradiated at a reduced intensity, the surface of the wafer 1 is detected. By measuring the scattered light e generated from a defect such as foreign matter e or COP existing in the predetermined region 10, it is not affected by noise due to strong diffracted light a generated at the edge portion d of the wafer 1 (or the influence is reduced). Thus, it is possible to accurately measure the state of defects such as foreign matter e and COP existing in the predetermined region 10 on the surface of the wafer 1.

  Next, by using the flowchart shown in FIG. 5, the presence of defects such as foreign matter e and COP existing on the surface of the wafer 1 by the wafer surface inspection apparatus in the present embodiment shown in FIG. A measurement flow of scanning the surface of the wafer 1 by irradiating Sp will be described.

  First, in step 101 for setting the inspection conditions for the wafer plane region, the data processing device 52 of the wafer surface inspection apparatus according to the present embodiment shown in FIG. Set the inspection conditions.

  Next, in step 102 for starting measurement, rotation of the rotary table 21 of the wafer surface inspection apparatus according to the present embodiment is started by a command from the drive controller 51, and the wafer 1 placed on the rotary table 21 is rotated. The measurement (scanning) is started while moving the position of the laser spot Sp of the laser beam Lt irradiated on the surface of the wafer 1 from the center in the radial direction of the wafer 1 toward the radially outer end.

  In step 104 during scanning of the planar area, the laser spot Sp of the laser beam Lt is irradiated to the planar area of the surface of the wafer 1 while moving the laser spot Sp from the radial center of the wafer 1 toward the radially outer end. Scan the surface.

  In step 105 for calculating a level obtained by averaging detection signals received by the respective light receivers for each round, scattered light Se detected by the light receiver while the laser spot Sp makes a round on the surface of the wafer 1. The level obtained by averaging the detection signals is calculated.

  A laser spot Sp of the laser beam Lt is continuously irradiated concentrically on the surface of the wafer 1, and scattered light Se scattered from a foreign substance e or a flaw existing on the surface of the wafer 1 is received by high angle light receivers 371 to 374. In addition, the detection signals that are received by the low-angle light receivers 381 to 386 are averaged for each turn by the data processing device 52 as described above, and the average level of the detection signals is calculated.

  Next, the output voltage V1 output from the light receiver disposed at the angle of the wafer 1 and receiving the diffracted light (or the influence of the diffracted light is large) and the radial direction of the wafer 1 are disposed. The wafer voltage direction (V1) for calculating the ratio (V1 / V2) of the output voltage to the output voltage V2 output from the light receiver arranged at an angle that is not subjected to diffracted light (or is less influenced by diffracted light) ) And the signal ratio of the optical receivers in the radial direction (V2), the process proceeds to step 106.

  The ratio (V1 / V2) of the output voltage (V1 / V2) of the light receiving signal detected by the light receiving device arranged in the diameter direction of the wafer 1 by the data processing device 52 and the light receiving signal detected by the light receiving device arranged in the radial direction. calculate.

  The position at which the surface of the wafer 1 is irradiated with the laser spot Sp of the laser beam Lt moves from the center of the surface of the wafer 1 toward the outer peripheral end in the radial direction. The movement of the position of the laser spot Sp is a linear movement mechanism 22. This is associated with the movement of the position of the wafer 1 by driving.

  Therefore, the laser spot Sp of the laser beam Lt is compared while comparing the input value of the movement amount of the linear movement mechanism 22 shown in FIG. 3 with the set value of the distance from the center of the wafer 1 to the predetermined region 10 on the surface of the wafer 1. The surface of the wafer 1 is scanned while being moved, and if the irradiation position approaches the predetermined area 10 from the plane area, the feed speed for moving the laser spot Sp of the laser beam Lt is set finely to adjust the wafer 1 The surface can be scanned concentrically.

  Then, along with the position data of the scanning position (detection position) of the laser spot Sp of the laser beam Lt that scans the surface of the wafer 1, it is scattered from defects such as foreign matter e or COP present on the surface of the wafer 1 received by the light receiver. The detection signal of the scattered light Se is calculated by an arithmetic unit (MPU) 73 of the data processing device 52 and processed.

  Then, the process proceeds to step 107 for determining the threshold value (Th) <V1 / V2, and the calculated value of the output voltage ratio V1 / V2 calculated by the calculator 73 of the data processing device 52 is shown in FIG. The laser spot Sp of the laser beam Lt is irradiated to the surface of the wafer 1 at a position where the calculated value of the output voltage ratio V1 / V2 exceeds the threshold Th by comparing with a preset threshold Th shown in FIG. The determined position is determined to be the boundary position Ep between the planar area on the surface of the wafer 1 and the predetermined area 10 corresponding to the edge d of the wafer 1.

  In order to accurately measure the boundary position Ep between the planar region of the surface of the wafer 1 and the predetermined region 10, when the laser spot Sp of the laser beam Lt irradiated on the surface of the wafer 1 approaches the vicinity of the predetermined region 10. The laser spot Sp of the laser beam Lt is finely fed so that the surface of the wafer 1 is irradiated with the laser spot Sp of the laser beam Lt concentrically.

  When the laser spot Sp of the laser beam Lt is irradiated in this way, the foreign matter e or defect is generated even if the foreign matter e or the defect exists at the irradiation position on the surface of the wafer 1 scanned concentrically. From a detection signal obtained by detecting the scattered light Se with a light receiver, a detection signal based on the scattered light Se generated from a foreign substance e or a defect is detected from a plurality of adjacent circumferential positions obtained by scanning the surface of the wafer 1 concentrically. Therefore, if the detection signal by the scattered light Se generated from the foreign matter e or the defect is deleted by the calculation of the calculator 73 of the data processing device 52, it corresponds to the planar area of the surface of the wafer 1 and the edge portion d of the wafer 1. It is possible to accurately determine the boundary position Ep with the predetermined region 10 to be performed.

  It should be noted that the feed amount of the laser spot Sp of the laser beam Lt irradiated to the surface of the wafer 1 when approaching the vicinity of the predetermined region 10 may be finely set to 1/4 to 1/2 of the normal feed amount. .

  Next, the entire region where the calculated value of the output voltage ratio V1 / V2 exceeds the threshold Th is determined as the predetermined region 10 on the surface of the wafer 1 corresponding to the edge portion d of the wafer 1.

  Then, the process proceeds to step 108 where the predetermined region 10 on the surface of the wafer 1 is discriminated as the predetermined region and the inspection condition is changed so as to correspond to the inspection in which the laser beam Lt is irradiated and scanned. When the computing unit 73 of the data processing device 52 determines that the scanning position by irradiating the spot Sp has shifted from the planar region to the predetermined region beyond the boundary position Ep, the computation of the data processing device 52 is performed. The inspection condition for the predetermined area for scanning by irradiating the laser spot Sp of the laser beam Lt to the predetermined area 10 of the wafer 1 is changed and set by the device 73.

  In other words, the intensity of the laser beam Lt irradiated from the laser light source 31 that irradiates the laser spot Sp of the laser beam Lt that scans the predetermined region 10 on the surface of the wafer 1 is adjusted or the scattered light Se is received. The light receiving sensitivity of the light receiving device is set so as to be lowered by adjusting the light receiving sensitivity of the light receiving device to receive the scattered light Se generated from the foreign matter e or the defect existing in the predetermined region 10 on the surface of the wafer 1.

  If the inspection conditions in the predetermined area 10 are changed and set as described above, the influence of strong diffracted light generated by the edge portion d on the surface of the wafer 1 is reduced, and the foreign matter existing in the predetermined area 10 on the surface of the wafer 1 It becomes possible to detect the scattered light Se generated from e or a defect. As a result, the foreign substance e or the defect existing in the predetermined region 10 can be detected.

  When the inspection in step 108 for determining the predetermined region and changing the inspection condition is completed, and in step 107 for determining threshold (Th) <V1 / V2, the calculated value of the output voltage ratio V1 / V2 Is only smaller than the threshold value Th, the process proceeds to step 103 of the measurement end position, and the scanning has been completed until the position of the laser spot Sp of the laser beam Lt reaches the measurement end position of the surface of the wafer 1 In step S109, the measurement is completed, and the measurement of the surface of the wafer 1 is completed.

  In the wafer surface inspection apparatus of this embodiment described above, the wafer 1 placed on the turntable 21 is rotated to irradiate the surface of the wafer 1 with the laser spot Sp of the laser beam Lt. e or scattered light Se generated from a defect is received by a light receiver to inspect the state of the foreign matter e or the defect. The deterioration of the light receiver and the decrease in the detection accuracy of the scattered light Se are caused by the following measures. Suppressed.

  That is, in the wafer surface inspection apparatus of the present embodiment, the detection sensitivity of the scattered light Se in the inspection of the predetermined region 10 on the surface of the wafer 1 corresponding to the edge portion d of the wafer 1 is suppressed. From among a plurality of light receivers that detect scattered light generated from a foreign substance e or a defect existing on the surface, a light receiver in an arrangement direction in which strong diffracted light generated at the edge portion d of the wafer 1 is not incident as much as possible is selected. Then, using the received light signal obtained by detecting the scattered light by the selected light receiver, the foreign matter e existing on the surface of the wafer 1 and defects such as scratches and crystal defects (COP) are detected with high accuracy.

  Further, the direction of the strong diffracted light a generated from the edge portion d of the wafer 1 is generated in the diameter direction of the wafer which is always the same direction with respect to the rotation of the wafer 1, so that the angle for receiving the diffracted light a is outside the angle. A light receiver is selected that detects the scattered light Se generated from the foreign matter e or defect existing on the surface of the wafer 1, and the wafer 1 is based on the light reception signal of the scattered light Se by the selected light receiver. The foreign substance e and the defect which exist on the surface of this are detected with high precision.

  That is, in the wafer surface inspection apparatus of this embodiment, the light receiver that detects the scattered light Se is not affected by the strong diffracted light a generated at the edge portion d of the wafer 1 shown in FIG. As light receivers for detecting scattered light generated from foreign matter e and defects existing on the surface of the wafer 1, among a large number of light receivers, high-angle light receivers 371 and 373 and low-angle light receiver 383 are used. 386, and by effectively detecting the scattered light Se generated from the foreign matter e or defect existing on the surface of the wafer 1 by these selected light receivers, the situation of the foreign matter e or the defect is accurately determined. Measuring (inspecting).

  In addition, the number of light receivers and the positions where they are arranged may be set as appropriate so as to avoid strong diffracted light a.

  According to the embodiment of the present invention, when the surface of the inspection object is inspected by irradiating the laser beam, the flat area to be inspected of the inspection object can be set as wide as possible. And an inspection apparatus for inspecting an object by accurately determining the boundary position between the predetermined area corresponding to the edge portion of the inspection object adjacent to the planar area.

  Next, an inspection object inspection apparatus according to another embodiment of the present invention will be described with reference to FIG.

  The inspection object inspection apparatus of the present embodiment shown in FIG. 6 is largely the same in configuration and operation as the inspection object inspection apparatus of the previous embodiment shown in FIGS. Therefore, the description of the configuration common to both is omitted, and only the configuration that is different will be described below.

  6, in the inspection apparatus for an inspection object according to the present embodiment, the boundary position Ep between the predetermined area 10 corresponding to the edge portion d on the surface of the wafer 1 and the flat planar area is determined by the surface of the wafer 1. A half mirror 501 that captures the shape of the laser spot Sp and the periphery of the laser spot Sp of the laser beam Lt irradiated on the surface, and the shape of the laser spot Sp and the periphery of the shape of the laser spot Sp reflected by the half mirror 501 are photographed. And the image data of the shape of the laser spot Sp taken by the observation camera 500 and the peripheral image data of the shape of the laser spot Sp of the boundary position Ep by the image recognition technique in the data processing device 52. The determination and the determination of the range of the predetermined area 10 are performed.

  In other words, a half mirror 501 is arranged in an optical path for irradiating the laser beam Lt in the vertical direction from the upper part of the surface of the wafer 1 as the inspection object to the surface of the inspection object, and the laser that has passed through the half mirror 501. The laser spot Sp of the laser beam Lt irradiated with the beam Lt or the mirror 331 from the optical path and irradiated obliquely toward the surface of the wafer 1 through the mirrors 332 and 35 is irradiated onto the surface of the wafer 1. An observation camera 500 that captures an image of the shape of the laser spot Sp reflected by the half mirror 501 and an image of the periphery of the shape of the laser spot Sp. It is equipped with.

  The half mirror 501 reflects the laser beam Lt output from the laser light source 31 in the projection optical system by the mirror 331 and vertically projects downward in the vertical direction toward the surface of the wafer 1, and the wafer. The position of the laser spot Sp that is transmitted through the surface of the wafer 1 and that is irradiated on the surface of the wafer 1 so that the image of the position of the laser spot Sp of the laser beam Lt irradiated onto the surface of 1 does not interfere with the image. In addition, the surrounding image is prepared for reflection in the direction in which the observation camera 500 is arranged and photographing.

  The observation camera 500 is configured to capture the shape of the laser spot Sp irradiated by the laser beam Lt irradiated by the light projecting optical system onto the surface of the wafer 1 and the number of pixels that can capture an image of the periphery of the laser spot Sp. And have resolution.

  In the present embodiment, the surface of the wafer 1 is irradiated with the laser spot Sp of the laser beam Lt, and the shape of the laser spot Sp irradiated on the surface of the wafer 1 during scanning, and the periphery of the laser spot Sp. The image of the image is taken by the observation camera 500, sequentially obtained as image data, and the image data is analyzed by an image recognition technique by the data processing device 52 provided in the inspection apparatus of the present embodiment to obtain the surface of the wafer 1 The boundary position Ep between the planar area and the predetermined area and the range of the predetermined area 10 corresponding to the edge portion of the wafer 1 are discriminated.

  That is, the shape of the laser spot Sp of the laser beam Lt photographed by the observation camera 500 is circular when the position irradiated with the laser spot Sp is in a planar region on the surface of the wafer 1, When the irradiation position of the laser spot Sp enters a boundary position Ep where the irradiation position changes from the planar area to the predetermined area 10 corresponding to the edge part d of the wafer 1, the shape of the laser spot Sp changes to an elliptical shape by the inclined surface of the edge part d. To do.

  For this reason, if an image recognition technique for pattern matching the shape of the laser spot Sp photographed by the observation camera 500 in the data processing device 52 is applied, the plane region between the surface of the wafer 1 and the predetermined region 10 is applied. The boundary position Ep can be determined with high accuracy.

  Further, the range of the predetermined region 10 corresponding to the edge portion d of the wafer 1 can be determined by the same method as described above.

  Further, the scattered light Se scattered by the foreign matter e existing on the surface of the wafer 1 and the defects such as scratches and crystal defects (COP) are received by the high angle light receivers 371 to 374 and the low angle as in the previous embodiment. The received light signals detected by the light receivers 381 to 386 are sent to the foreign object detector 4 and the data processing device 52 for calculation processing, and the size and position of the foreign object e and defects are displayed on the display 75. It is comprised so that it may be displayed.

  In this embodiment, the determination of the boundary position Ep and the determination of the state of the foreign matter e and defects present on the surface of the wafer 1 are the same as those in the previous embodiment described with reference to FIGS. Although the description is omitted, the boundary position Ep between the planar region on the surface of the wafer 1 and the predetermined region 10 is determined with high accuracy, and the scattered light Se generated from the foreign matter e or the defect existing on the surface of the wafer 1. Can be effectively detected by a light receiver, and the state of the foreign matter e and defects can be measured with high accuracy.

  According to the embodiment of the present invention, when the surface of the inspection object is inspected by irradiating the laser beam, the flat area to be inspected of the inspection object can be set as wide as possible. And an inspection apparatus for inspecting an object by accurately determining the boundary position between the predetermined area corresponding to the edge portion of the inspection object adjacent to the planar area.

  Next, an inspection object inspection apparatus according to still another embodiment of the present invention will be described with reference to FIG.

  The inspection device inspection apparatus of the present embodiment shown in FIG. 7 is also mostly in common with the configuration and operation of the inspection object inspection apparatus of the previous embodiment shown in FIGS. Therefore, description of the configuration common to both is omitted, and only the configuration that is different will be described below.

  In FIG. 7, in the inspection apparatus for an inspected object according to the present embodiment, the boundary position Ep between the flat planar region on the surface of the wafer 1 and the predetermined region corresponding to the edge portion d is determined, and the determination and predetermined region 10 are determined. And the status of foreign matter e and defects existing on the surface of the wafer 1 are determined by irradiating the surface of the wafer 1 with the laser spot Sp of the laser beam Lt and scattering light Se scattered on the surface of the wafer 1. In order to receive light, a plurality of condensing mirrors 601 that are installed above the wafer 1 and reflect the scattered light Se, and to receive the scattered light Se reflected by the plurality of condensing mirrors 601. For example, a line sensor 600 having a configuration in which a large number of sensors are arranged in an annular shape is installed, and the sensor of the line sensor 600 that receives scattered light Se reflected by the condenser mirror 601 is installed. In accordance with the received light, a sensor is sent to the foreign object detector 4 and the data processing device 52 based on the light reception signal of the received sensor for calculation processing, and the size and position of the foreign object e and the defect are displayed on the display 75 or the like. Has been.

  As a result, the boundary position Ep between the flat planar region on the surface of the wafer 1 and the predetermined region 10 corresponding to the edge portion d, the determination of the range of the predetermined region 10, and the surface of the wafer 1 exist. The state of the foreign matter e and the defect is determined, and the position of the boundary position Ep and the size and position of the foreign matter e and the defect are displayed on the display 75 or the like.

  The effect of using the line sensor 600 that receives the scattered light Se in the present embodiment is that even if intense diffracted light is incident as compared with the light receiver of the previous embodiment using a photomultiplier tube (PMT). The point which is hard to do is raised.

  Also in the line sensor 600 of this embodiment, similarly to the case where the scattered light Se is received by the light receiver of the previous embodiment, it is affected by the strong diffracted light a generated in the diameter direction of the wafer 1 or this diffraction. The light receiving signal V1 of the scattered light Se scattered from the surface of the wafer 1 in a region susceptible to the light a and the weak diffracted light b generated in the tangential direction of the edge portion of the wafer 1 or the diffracted light b The received light signal V2 of the scattered light Se scattered from the surface of the wafer 1 in the region that is susceptible to the above is acquired.

  Then, similarly to the arithmetic processing in the previous embodiment shown in FIGS. 1 to 5, the ratio of the output voltage V1 of the received light signal and the output voltage V2 of the received light signal detected by the plurality of sensors of the line sensor 600 ( The value of V1 / V2) is compared with an arbitrarily set threshold Th, and the position of the surface of the wafer 1 exceeding the threshold Th corresponds to the flat surface region of the wafer 1 and the edge portion d of the wafer 1. It is possible to accurately determine the boundary position Ep between the predetermined area.

  Further, in the line sensor 600 of the present embodiment, the scattered light Se scattered by the foreign matter e and defects existing on the surface of the wafer 1 can be received without being affected by the diffracted light so much. The situation can be detected with high accuracy.

  Further, when measuring the state of the foreign matter e or defect existing in the predetermined region 10 corresponding to the edge portion, the sensor of the line sensor 600 located within an angle range that is not affected by the strong diffracted light a that becomes noise. By selecting a portion, it is possible to minimize the decrease in sensitivity and to inspect the foreign matter e and defects existing in the predetermined region 10.

  Thus, by accurately determining the boundary position Ep between the surface area of the wafer 1 and the predetermined area, not only can the flat planar area of the surface of the wafer 1 be used to the maximum, but also the conventional measurement. Thus, it becomes possible to manage the state of foreign matter e and defects in a predetermined area corresponding to the edge portion d of the wafer 1, so that the critical defect of the wafer 1 is not overlooked.

  Therefore, it is possible to greatly reduce the defects of the semiconductor IC manufactured from the wafer 1 inspected by applying this embodiment.

  According to the embodiment of the present invention, when the surface of the inspection object is inspected by irradiating the laser beam, the flat area to be inspected of the inspection object can be set as wide as possible. And an inspection apparatus for inspecting an object by accurately determining the boundary position between the predetermined area corresponding to the edge portion of the inspection object adjacent to the planar area.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an inspection object inspection apparatus that inspects the surface state of an inspection object such as a wafer, and in particular, an inspection object inspection apparatus that inspects the surface of an inspection object such as a wafer by irradiating a laser beam. Is available.

  1: Wafer, 10: Predetermined area, 21: Rotary table, 22: Linear movement mechanism, 31: Laser light source, 331, 332, 35: Mirror, 371-374: High angle light receiver, 381-386: Low angle Light receiver, 4: Foreign object detector, 51: Drive controller, 52: Data processing device, 500: Observation camera, 501: Half mirror, 600: Line sensor, 601: Condensing mirror, 75: Display, a: Strong diffraction Light, b: weak diffracted light, c: laser light, d: edge, e: foreign material, Sp: laser spot, Lt: laser beam, Se: scattered light, Ep: boundary position, Th: threshold.

Claims (4)

A laser light source that emits a laser beam to irradiate the surface of the object to be inspected;
A rotary table for placing and rotating the inspection object;
A moving mechanism for moving the rotary table in the transfer direction of the inspection object;
A camera that captures an image of the laser spot of the laser beam irradiated on the surface of the object to be inspected, and an image around the laser spot;
A data processing apparatus that obtains a range of a wafer edge portion deviating from a flat planar region of the surface of the object to be inspected by the laser beam using the image of the laser spot and an image around the laser spot; An inspection apparatus comprising: The inspection apparatus according to claim 1,
The data processing apparatus obtains a boundary position between the surface region and the wafer edge portion. The inspection apparatus according to claim 1,
The data processing device performs pattern matching on the image of the laser spot. The inspection apparatus according to claim 1,
A half mirror that transmits the laser beam installed in the middle of an optical path that irradiates the laser beam in a vertical direction with respect to the surface of the inspection object;
The inspection apparatus, wherein the camera captures an image of a laser spot of the laser beam reflected on the half mirror and an image around the laser spot.

Images