JP2010117323A - Surface inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface inspection apparatus that reduces the inspection time. <P>SOLUTION: A surface inspection apparatus 1 includes: edge detectors 30-50 to detect the status in the vicinity of an edge on a wafer 10; an arithmetic processing unit 70 to perform inspection in the vicinity of the edge on the wafer 10 depending on the outputs from the edge detectors 30-50; and a wafer holding section 20 for performing relative rotation of the wafer 10 relative to the edge detectors 30-50. The edge detectors 30-50 detect the status in the vicinity of the edge on the wafer 10 while performing the relative rotation by the wafer holding section 20, and the arithmetic processing unit 70 performs inspection in the vicinity of the edge on the wafer 10 depending on the outputs from the edge detectors 30-50. Pre-alignment sensors 61-63 are provided that detect an edge on the wafer 10. Depending on the outputs from the pre-alignment sensors 61-63, the arithmetic processing unit 70 corrects an operating status of the first and second edge detectors 30, 40, and the output from the third edge detector 50 to the arithmetic processing unit 70. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface inspection apparatus that inspects the surface of an end portion of a substrate such as a semiconductor wafer or a liquid crystal glass substrate.

  Various surface inspection apparatuses for inspecting the surface state of an inspection object have been devised (see, for example, Patent Document 1), but in recent years, as the degree of integration of circuit element patterns formed on a semiconductor wafer increases, Inspection of the edge of the wafer has become important. If there is an abnormality such as a foreign substance at the edge of the wafer or in the vicinity of the edge, the foreign substance or the like moves to the surface side of the wafer in a subsequent process and has an adverse effect, thereby affecting the yield of circuit elements created from the wafer.

Therefore, the vicinity (for example, apex and upper and lower bevels) of the substrate formed in the shape of a disk such as a semiconductor wafer is observed (detected) from a plurality of directions to remove foreign matter and film, bubbles in the film, film A surface inspection apparatus has been devised for inspecting whether there is an abnormality such as wraparound. Such a surface inspection apparatus utilizes a configuration in which an image near the edge of the substrate is continuously picked up while rotating the substrate to detect foreign matters, or scattered light generated by irradiation with laser light or the like. There is a configuration for detecting foreign matter and the like.
JP 2008-64656 A

  In such a surface inspection apparatus, in order to inspect all substrates, it has been an important issue how much information on the entire circumference of the substrate can be detected.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a surface inspection apparatus that shortens the inspection time.

  In order to achieve such an object, the surface inspection apparatus according to the present invention includes an edge detector that detects a state in the vicinity of an end portion of a substrate formed in a substantially disc shape, and the output from the edge detector. An inspection unit for inspecting the vicinity of the edge of the substrate; and a relative rotation unit for rotating the substrate relative to the edge inspection device with a rotational symmetry axis of the substrate as a rotation axis, and the relative rotation by the relative rotation unit. In the surface inspection apparatus in which the edge detector detects a state in the vicinity of the end of the substrate while performing the inspection, and the inspection unit inspects in the vicinity of the end of the substrate based on an output from the edge detector. Based on the output from the pre-alignment sensor that detects the edge of the substrate and the pre-alignment sensor, the operation of the edge detector or the output from the edge detector to the inspection unit is small. And also configured and a correcting section for correcting one.

  In the above-described invention, the edge detector uses an illumination unit that illuminates oblique light near the end of the substrate, and a plurality of photodetectors arranged in a hemisphere so as to cover the end of the substrate. A detection unit that detects a distribution of light from the vicinity of the edge of the substrate that is illuminated with the oblique light, and the inspection unit uses the distribution of the light output from the detection unit to the inspection unit. It is preferable to inspect the vicinity of the end of the substrate based on the above.

  In the above-described invention, in the edge detector, the illuminating unit illuminates oblique light near the end portion on the front surface or the back surface of the substrate, and the detection unit emits light from the vicinity of the end portion on the front surface or the back surface of the substrate. The illumination unit has a variable diaphragm that can change the illumination position of the oblique light, and the correction unit is based on an output from the pre-alignment sensor, It is preferable to have a drive control unit that drives and controls the variable diaphragm so that the oblique illumination position with respect to the vicinity of the end of the substrate is constant.

  In the above-described invention, in the edge detector, the illumination unit illuminates the edge of the substrate from the extending direction of the substrate, and the detection unit detects the light distribution from the end of the substrate. Preferably, the correction unit includes a position correction unit that corrects position information of the light distribution detected by the detection unit based on an output from the pre-alignment sensor. .

  In the above-described invention, it is preferable that the edge detector and the pre-alignment sensor are disposed at positions separated from each other by 180 degrees with the rotational symmetry axis of the substrate as a rotation axis.

  Furthermore, in the above-described invention, three sets of the edge detector and the pre-alignment sensor are provided, and are arranged at predetermined angular intervals around the rotational symmetry axis of the substrate, and the three sets of the edge The first edge detector of the detectors detects a state in the vicinity of the end of the substrate from the surface side of the substrate, and the second edge detector of the three sets of the edge detectors is the substrate. The state near the edge of the substrate is detected from the back side of the substrate, and the third edge detector of the three sets of edge detectors detects the state near the edge of the substrate from the extending direction of the substrate. It is preferable to detect.

  Moreover, in the above-mentioned invention, it is preferable that the pre-alignment sensor is a line sensor that detects an end portion of the substrate from a front surface or a back surface side of the substrate.

  According to the present invention, the inspection time can be further shortened.

  Hereinafter, preferred embodiments of the present invention will be described. The surface inspection apparatus of this embodiment is shown in FIG. 1 and FIG. 2, and this surface inspection apparatus 1 is configured to detect abnormalities (scratches, foreign matter) at and near the end of a semiconductor wafer 10 (hereinafter referred to as wafer 10). It is for inspecting the presence or absence of adhesion).

  The wafer 10 is formed in a thin disk shape, and an insulating film and electrodes are formed on its surface in order to form a circuit pattern (not shown) corresponding to a plurality of semiconductor chips (chip regions) taken out from the wafer 10. A thin film (not shown) such as a wiring film or a semiconductor film is formed over multiple layers. As shown in FIG. 3, an upper bevel portion 11 is formed in a ring shape inside the outer peripheral end portion on the surface (upper surface) of the wafer 10, and a circuit pattern is formed inside the upper bevel portion 11. . Further, a lower bevel portion 12 is formed symmetrically with the upper bevel portion 11 with respect to the wafer 10 on the inner side of the outer peripheral end portion on the back surface (lower surface) of the wafer 10. The wafer end face connected to the upper bevel portion 11 and the lower bevel portion 12 becomes the apex portion 13.

  By the way, as shown in FIGS. 1 and 2, the surface inspection apparatus 1 includes a wafer holding unit 20 that rotatably holds the wafer 10, and three edge detectors 30 that detect a state near the end of the wafer 10, 40, 50, three pre-alignment sensors 61-63 for detecting the edge of the wafer 10, and arithmetic processing for performing predetermined arithmetic processing based on the light detection signals input from the edge detectors 30, 40, 50 The unit 70 and a monitor 75 that displays a processing result and the like by the arithmetic processing unit 70 are mainly configured.

  The wafer holding unit 20 supports the wafer 10 on the upper surface side by being attached substantially horizontally to the base 21, the rotary shaft 22 provided vertically extending from the base 21, and the upper end of the rotary shaft 22. And a wafer holder 23. A vacuum suction mechanism (not shown) is provided inside the wafer holder 23, and the wafer 10 on the wafer holder 23 is suction-held using vacuum suction by the vacuum suction mechanism.

  A rotation drive mechanism (not shown) for rotating the rotation shaft 22 is provided inside the base 21, and the rotation shaft 22 is rotated counterclockwise as viewed from above, for example, by the rotation drive mechanism. Together with the wafer holder 23 attached to the rotating shaft 22, the wafer 10 sucked and held on the wafer holder 23 is rotationally driven with the center of the wafer holder 23 (rotation symmetry axis AX) as the rotating axis. The rotation drive mechanism is supported by an XY table (not shown) provided inside the base 21 so as to be horizontally movable, and the horizontal position of the wafer holder 23 that is rotationally driven by the rotation drive mechanism can be adjusted. It is like that. The wafer holder 23 is formed in a substantially disk shape having a diameter smaller than that of the wafer 10, and includes an upper bevel portion 11, a lower bevel portion 12, and an apex portion 13 with the wafer 10 being sucked and held on the wafer holder 23. The vicinity of the outer peripheral end of the wafer 10 protrudes from the wafer holder 23.

  The first edge detector 30 includes a first illuminating unit 31 that illuminates oblique light L1 in the vicinity of an end portion (that is, the upper bevel portion 11) on the surface (upper surface) of the wafer 10, and an end of the wafer 10 that is illuminated by the oblique light L1. And a first detection unit 36 that detects the distribution of light from the vicinity of the unit (upper bevel unit 11). The first illumination unit 31 includes a first light source 32 and a first collimator lens 33, and the optical axis thereof is configured to be inclined with respect to the normal line of the upper bevel surface of the wafer 10. The oblique light L1 emitted from the first light source 32 is converted into parallel light by the first collimator lens 33 and is illuminated near the end portion (upper bevel portion 11) of the wafer 10 covered by the first detection unit 36. . In addition, a first variable stop 34 capable of changing the illumination position of the oblique light L <b> 1 is provided between the first light source 32 and the first collimator lens 33.

  The first detection unit 36 includes a first housing unit 37 that covers the vicinity of the end of the wafer 10, and a plurality of photodetectors (not shown) attached to the inside of the first housing unit 37. Configured. The first housing portion 37 is formed in a hemispherical dome shape, and is arranged so as to cover the vicinity of the end portion of the wafer 10 (near the upper bevel portion 11) from above (without contact). At this time, the center (rotation target axis) of the first casing portion 37 is positioned above the end portion of the wafer 10. The first casing portion 37 is formed with an opening 38 through which the oblique light L1 from the first illuminating portion 31 passes inside the first casing portion 37 (first detection portion 36). This opening 38 is preferably as small as possible so that as many photodetectors as possible can be arranged.

  The second edge detector 40 includes a second illuminator 41 that illuminates oblique light L2 in the vicinity of the end portion (that is, the lower bevel portion 12) on the back surface (lower surface) of the wafer 10, and an end of the wafer 10 that is illuminated by the oblique light L2. And a second detection unit 46 that detects the distribution of light from the vicinity of the unit (lower bevel unit 12). The second illumination unit 41 includes a second light source 42 and a second collimator lens 43, and the optical axis thereof is configured to be inclined with respect to the normal line of the lower bevel surface of the wafer 10. The oblique light L <b> 2 emitted from the second light source 42 becomes parallel light by the second collimator lens 43 and is illuminated near the end of the wafer 10 (the lower bevel portion 12) covered by the second detection unit 46. . In addition, a second variable stop 44 capable of changing the illumination position of the oblique light L2 is provided between the second light source 42 and the second collimator lens 43.

  The second detection unit 46 includes a second casing unit 47 that covers the vicinity of the end of the wafer 10, and a plurality of photodetectors (not shown) attached to the inside of the second casing unit 47. The first detection unit 36 is disposed at a position rotated 45 degrees clockwise (as viewed from above) about the rotational symmetry axis AX of the wafer 10 as a rotation axis. The second casing 47 is formed in a hemispherical dome shape, and is disposed so as to cover the vicinity of the end of the wafer 10 (the vicinity of the lower bevel 12) from below (without contact). At this time, the center (rotation target axis) of the second casing portion 47 is positioned below the end portion of the wafer 10. The second casing 47 is provided with an opening 48 through which the oblique light L2 from the second illumination unit 41 passes inside the second casing 47 (second detection unit 46). The opening 48 is preferably as small as possible so that as many photodetectors as possible can be arranged.

  The third edge detector 50 includes a third illuminating unit 51 that illuminates oblique light L3 on the end portion (that is, apex portion 13) of the wafer 10 from the extending direction of the wafer 10, and an end of the wafer 10 that is illuminated by the oblique light L3. And a third detector 56 that detects the distribution of light from the vicinity of the part (apex part 13). The third illumination unit 51 includes a third light source 52 and a third collimator lens 53, and the optical axis thereof is configured to be inclined with respect to the tangent line of the outer peripheral end of the wafer 10 at the illumination position. . The oblique light L3 emitted from the third light source 52 becomes parallel light by the third collimator lens 53 and is illuminated near the end portion (apex portion 13) of the wafer 10 covered by the third detection portion 56.

  The third detector 56 includes a third casing 57 that covers the vicinity of the end of the wafer 10, and a plurality of photodetectors 59 (see FIG. 4) attached to the inside of the third casing 57. And is disposed at a position away from the second detection unit 46 by rotating 45 degrees clockwise about the rotational symmetry axis AX of the wafer 10 (viewed from above). The third housing portion 57 is formed in a hemispherical dome shape, and the end portion of the wafer 10 (near the apex portion 13) is viewed from the side (the extending direction of the wafer 10) (without contact). Arranged to cover. At this time, the center (rotation target axis) of the third casing portion 57 is directed in the radial direction of the wafer 10 (direction from the outer peripheral portion to the rotational symmetry axis). The third housing part 57 has an opening 58 through which the oblique light L3 from the third illumination part 51 passes inside the third housing part 57 (third detection part 56). The opening 58 is preferably as small as possible so that as many photodetectors as possible can be arranged.

  As the plurality of photodetectors 59 attached to the inside of the third housing portion 57, for example, photodiodes with good response are used. As shown in FIG. It arrange | positions side by side continuously so that an internal peripheral surface may be comprised (namely, in a dome shape). Thereby, it is possible to detect the distribution of light such as specularly reflected light, diffracted light, and scattered light generated in the vicinity of the end portion (apex portion 13) of the wafer 10 illuminated with the oblique light L3. The light detection signals detected by the light detector 59 are output to the arithmetic processing unit 70, respectively. A plurality of photodetectors (not shown) attached to the inside of the first casing 37 in the first edge detector 30 and the inside of the second casing 47 in the second edge detector 40. The plurality of photodetectors (not shown) attached to the same configuration as the plurality of photodetectors 59 attached to the inside of the third casing portion 57 are detected by the respective photodetectors. The photodetection signals are output to the arithmetic processing unit 70, respectively.

  The first pre-alignment sensor 61 shown in FIG. 1 and FIG. 2 is configured using, for example, a CCD line sensor, and is disposed above the wafer 10 and detects the edge of the wafer 10 from the front side of the wafer 10. . Further, as shown in FIG. 1, the first pre-alignment sensor 61 is positioned 180 degrees away from the first detection unit 36 of the first edge detector 30 with the rotational symmetry axis AX of the wafer 10 as the rotation axis. In addition, the longitudinal direction of the first pre-alignment sensor 61 faces the radial direction of the wafer 10.

  The second pre-alignment sensor 62 is also configured using, for example, a CCD line sensor, and is disposed above the wafer 10 and detects the edge of the wafer 10 from the front side of the wafer 10. In addition, the second pre-alignment sensor 62 is disposed at a position away from the second detection unit 46 of the second edge detector 40 by rotating 180 degrees about the rotational symmetry axis AX of the wafer 10 as a rotation axis. The longitudinal direction of the 2 pre-alignment sensor 62 is directed to the radial direction of the wafer 10. In other words, the second pre-alignment sensor 62 is disposed at a position away from the first pre-alignment sensor 61 by rotating 45 degrees clockwise with the rotational symmetry axis AX of the wafer 10 as the rotation axis (as viewed from above). . In FIG. 2, the description of the second pre-alignment sensor 62 is omitted for ease of explanation.

  The third pre-alignment sensor 63 is also configured using, for example, a CCD line sensor, and is disposed above the wafer 10 and detects the edge of the wafer 10 from the front surface side of the wafer 10. The third pre-alignment sensor 63 is disposed at a position away from the third detection unit 56 of the third edge detector 50 by rotating 180 degrees about the rotational symmetry axis AX of the wafer 10 as a rotation axis. The longitudinal direction of the 3 pre-alignment sensor 63 is directed to the radial direction of the wafer 10. In other words, the third pre-alignment sensor 63 is disposed at a position away from the second pre-alignment sensor 62 by rotating 45 degrees clockwise about the rotational symmetry axis AX of the wafer 10 (viewed from above). . The light detection signals detected by the first to third pre-alignment sensors 61 to 63 are output to the arithmetic processing unit 70, respectively.

  The arithmetic processing unit 70 performs predetermined arithmetic processing based on the light detection signals respectively input from the photodetectors of the first to third edge detectors 30, 40, 50, and near the end of the wafer 10, that is, Each of the upper bevel part 11, the lower bevel part 12, and the apex part 13 is inspected for abnormalities. Further, the arithmetic processing unit 70 has a database 71 that stores light distribution information (light intensity distribution information described later) according to the type of abnormality.

  In the surface inspection apparatus 1 configured as described above, abnormalities (such as attachment of scratches or foreign matters) in the vicinity of the edge of the wafer 10 (upper bevel portion 11, lower bevel portion 12, and apex portion 13) using dark field observation. In order to inspect the presence / absence), first, the wafer 10 to be inspected is placed on the wafer holder 23 of the wafer holding unit 20 by a transfer device (not shown), and the wafer holder 23 holds the wafer 10 by suction using vacuum suction. To do.

  When the wafer holding unit 20 sucks and holds the wafer 10, the first illumination unit 31 of the first edge detector 30 illuminates the oblique light L 1 near the upper bevel portion 11 of the wafer 10, and the second illumination of the second edge detector 40. The portion 41 illuminates the oblique light L2 near the lower bevel portion 12 of the wafer 10, and the third illumination portion 51 of the third edge detector 50 illuminates the oblique light L3 near the apex portion 13 of the wafer 10. At this time, since the vicinity of the apex portion 13 is covered by the dome-shaped third detection unit 56, the oblique light L <b> 3 is illuminated if there is no scratch or foreign matter (dust, dust, etc.) in the vicinity of the apex portion 13. The regular reflection light from the apex unit 13 is detected by the photodetector 59 of the third detection unit 56 corresponding to the arrival position of the regular reflection light.

  Similarly, since the vicinity of the upper bevel portion 11 is covered by the dome-shaped first detection unit 36, the oblique light L1 is generated if there is no damage or foreign matter (dust or dust) attached to the vicinity of the upper bevel portion 11. The regularly reflected light from the illuminated upper bevel portion 11 is detected by a photodetector (not shown) of the first detector 36 corresponding to the arrival position of the regularly reflected light. Similarly, since the vicinity of the lower bevel portion 12 is covered by the dome-shaped second detection unit 46, the oblique light L <b> 2 is present if there is no scratch or foreign matter (dust or dust) attached to the vicinity of the lower bevel portion 12. Is reflected by the photodetector (not shown) of the second detection unit 46 corresponding to the arrival position of the regular reflection light.

  On the other hand, as shown in FIG. 4A, for example, when foreign matter D exists on the apex portion 13 of the wafer 10, the oblique light L3 illuminated on the portion where the foreign matter D exists is reflected (or diffracted) here. The scattered light (or diffracted light) that is the reflected light is detected by any one of the photodetectors 59 of the third detector 56. The right side of FIG. 4A illustrates the distribution of light reaching the inner surface of the hemispherical third housing portion 57. For example, there is no scratch or foreign matter in the vicinity of the apex portion 13. For example, the regular reflection light R <b> 1 is detected from the apex portion 13. Further, for example, when forward scattering along the traveling direction of the oblique light L3 occurs strongly, light such as the first scattered light R2 is detected, and when scattering occurs over a wide range, the second scattered light R3 is detected. When the backscattering on the opposite side to the traveling direction of the oblique light L3 occurs strongly, the light such as the third scattered light R4 is detected.

  Similarly, when a foreign matter exists on the upper bevel portion 11 of the wafer 10, the oblique light L <b> 1 illuminated on the portion where the foreign matter is present is reflected (or diffracted) here, and scattered light (or diffracted light) that is the reflected light. Light) is detected by one of the photodetectors (not shown) of the first detector 36. Similarly, when there is a foreign substance on the lower bevel portion 12 of the wafer 10, the oblique light L2 illuminated on the part where the foreign substance exists is reflected (or diffracted) here, and the scattered light (or the reflected light) (Diffracted light) is detected by one of the photodetectors (not shown) of the second detector 46.

  At this time, the first illumination unit 31 illuminates the oblique light L1 in the vicinity of the upper bevel portion 11 of the wafer 10 while rotating the wafer 10 by the wafer holding unit 20, and any one of the photodetectors ( (Not shown) continuously detects the distribution of light such as specularly reflected light, diffracted light, and scattered light generated in the upper bevel portion 11. Similarly, while rotating the wafer 10 by the wafer holding unit 20, the second illumination unit 41 illuminates the oblique light L2 in the vicinity of the lower bevel portion 12 of the wafer 10, and any one of the photodetectors (see FIG. (Not shown) continuously detects the distribution of light such as specularly reflected light, diffracted light, and scattered light generated at the lower bevel portion 12. Similarly, while rotating the wafer 10 by the wafer holding unit 20, the third illumination unit 31 illuminates the oblique light L3 in the vicinity of the apex unit 13 of the wafer 10, and any one of the photodetectors 59 of the third detection unit 56 is activated. The distribution of light such as specularly reflected light, diffracted light, and scattered light generated at the apex unit 13 is continuously detected. The rotation angle of the wafer 10 when the light distribution is detected for each detection unit is also detected.

  Accordingly, the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13 can be efficiently inspected over the entire circumference of the wafer 10. In addition, by using a photodiode with good responsiveness as the photodetector 59, the light detection time is shortened, so that the wafer 10 can be rotated at a relatively high speed, and inspection is performed in a short time. be able to.

  When the light detector 59 of the third detection unit 56 detects light from the apex unit 13, it outputs a light detection signal to the arithmetic processing unit 70. When the light detection signal is input from the light detector 59, the arithmetic processing unit 70 performs an integration process or the like based on the input light detection signal, thereby performing the illumination direction of the oblique light L3 (the outer peripheral edge of the wafer 10). 1-dimensional light intensity distribution along the tangential direction at (). The light intensity distribution excludes specularly reflected light, and the degree of abnormality (defect) increases as the light intensity increases.

  In addition, the light intensity distribution varies depending on the size, shape, surface state, and the like of the abnormality. Therefore, the database 71 stores information on the light intensity distribution according to the type of abnormality, and the arithmetic processing unit 70 uses the light intensity distribution generated based on the light detection signal from the light detector 59 as the database. It is determined that there is an abnormality when the generated light intensity distribution is equivalent to the light intensity distribution recorded in the database 71 as compared with the light intensity distribution according to the type of abnormality of the apex portion 13 recorded in 71. The type of abnormality detected from the type of the corresponding light intensity distribution is classified.

  Similarly, when a light detector (not shown) of the first detection unit 36 detects light from the upper bevel unit 11, it outputs a light detection signal to the arithmetic processing unit 70, and the arithmetic processing unit 70 is inputted. Based on the detected light signal, a one-dimensional light intensity distribution along the illumination direction of the oblique light L1 (the tangential direction at the outer peripheral edge of the wafer 10) is generated. Then, the generated light intensity distribution is compared with the light intensity distribution according to the type of abnormality of the upper bevel portion 11 recorded in the database 71, and the generated light intensity distribution is compared with the light intensity distribution recorded in the database 71. If they are equivalent, it is determined that there is an abnormality, and the type of abnormality detected is classified from the type of the corresponding light intensity distribution.

  Similarly, when a light detector (not shown) of the second detection unit 46 detects light from the lower bevel unit 12, it outputs a light detection signal to the arithmetic processing unit 70, and the arithmetic processing unit 70 Based on the light detection signal thus generated, a one-dimensional light intensity distribution along the illumination direction of the oblique light L2 (the tangential direction at the outer peripheral edge of the wafer 10) is generated. Then, the generated light intensity distribution is compared with the light intensity distribution according to the type of abnormality of the lower bevel portion 12 recorded in the database 71, and the generated light intensity distribution is compared with the light intensity distribution recorded in the database 71. If they are equivalent, it is determined that there is an abnormality, and the type of abnormality detected is classified from the type of the corresponding light intensity distribution.

  If the arithmetic processing unit 70 determines that there is an abnormality in any of the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13 of the wafer 10, it is near the end of the wafer 10 (upper bevel portion 11, lower bevel portion 11). (Any one of the section 12 and the apex section 13) that the abnormality is detected and the rotation angle of the wafer 10 at that time (that is, the position where the abnormality exists) are displayed on the monitor 75.

  By the way, when the wafer 10 is rotated by the wafer holding unit 20, the three pre-alignment sensors 61 to 63 detect the end portions of the wafer 10 and output detection signals to the arithmetic processing unit 70. At this time, the arithmetic processing unit 70 is based on the detection signals input from the three pre-alignment sensors 61 to 63, and the positions of the three outer peripheral end portions of the wafer 10 detected by the pre-alignment sensors 61 to 63. For each. If the position of the outer peripheral end portion of the wafer 10 formed in a disk shape is obtained at three locations, the position of the center (rotation symmetry axis AX) of the wafer 10 can be obtained. The center position of the wafer 10 is obtained based on the obtained positions of the three peripheral end portions of the wafer 10. The arithmetic processing unit 70 obtains the eccentricity (eccentricity and eccentricity direction) of the center of the wafer 10 with respect to the rotation center of the wafer holder 23, and performs the correction described below.

  In the first edge detector 30 that detects the state of the upper bevel portion 11, when the center of the wafer 10 (rotation symmetry axis AX) is decentered with respect to the rotation center of the wafer holder 23, the apparent appearance of the wafer 10 occurs when the wafer 10 rotates. Since the position is moved, the illumination range S1 of the oblique light L1 by the first illumination unit 31 moves relative to the upper bevel unit 11 as the wafer 10 rotates as shown in FIG. Therefore, the arithmetic processing unit 70 outputs a drive signal to the first variable aperture 34 and synchronizes with the outputs from the three pre-alignment sensors 61 to 63, that is, according to the eccentricity of the center of the wafer 10. Driving control of the first variable stop 34 is performed so that the illumination condition is constant with respect to the upper bevel part 11 of the oblique light L1 with respect to the bevel part 11 (for example, the central part in the width direction of the bevel coincides with the central part of the illumination). (Feedback control). Specifically, the outer peripheral side end of the illumination range S1 is fixed, the inner peripheral side end of the illumination range S1 is moved, and the first variable stop 34 so that the illumination range in the upper bevel portion 11 is constant. Is controlled. As a result, the illumination range (illumination position and light amount) of the oblique light L1 in the upper bevel portion 11 is constant with respect to the bevel regardless of the eccentricity of the center of the wafer 10, so that inspection is performed under the same conditions over the entire circumference of the wafer 10. It becomes possible to do.

  Further, in the second edge detector 40 that detects the state of the lower bevel portion 12, as in the case of the first edge detector 30, the arithmetic processing unit 70 outputs a drive signal to the second variable diaphragm 44, In synchronization with the outputs from the three pre-alignment sensors 61 to 63, that is, according to the eccentricity of the center of the wafer 10 (rotation symmetry axis AX), the lower bevel portion 12 with respect to the lower bevel portion 12 is illuminated. The second variable stop 44 is driven and controlled (feedback control) so that the condition is constant (for example, the central portion in the width direction of the bevel coincides with the central portion of the illumination). Specifically, the outer peripheral side end of the illumination range S2 is fixed and the inner peripheral side end of the illumination range S2 is moved so that the illumination range in the lower bevel portion 12 is constant with respect to the bevel. The variable aperture 44 is driven and controlled. Accordingly, the illumination range (illumination position and light amount) of the oblique light L2 in the lower bevel portion 12 is constant regardless of the eccentricity of the center of the wafer 10, so that the inspection can be performed under the same conditions over the entire circumference of the wafer 10. It becomes possible.

  In the third edge detector 50 that detects the state of the apex portion 13, when an eccentricity of the center of the wafer 10 (rotation symmetry axis AX) with respect to the rotation center of the wafer holder 23 occurs, the apparent position of the wafer 10 when the wafer 10 rotates. Therefore, the illumination range S3 of the oblique light L3 by the third illumination unit 51 moves relative to the apex unit 13 with the rotation of the wafer 10, as shown in FIG. In particular, since the illumination range S3 is relatively moved in the optical axis direction of the oblique light L3, the oblique light L3 is illuminated at a circumferential position of the wafer 10 different from the position to be originally illuminated. At this time, as shown in FIG. 4B, the distribution of light detected by the third detection unit 56 also moves around the regular reflection light R1.

  Therefore, the arithmetic processing unit 70 synchronizes with the outputs from the three pre-alignment sensors 61 to 63, that is, according to the eccentricity of the center of the wafer 10, the position of the light distribution detected by the third detection unit 56. The information is corrected. Specifically, from the amount of eccentricity of the center of the wafer 10 and the inclination angle of the oblique light L3, and the rotation angle of the wafer 10 actually detected when the light distribution is detected by the third detection unit 56, the oblique light is obtained. The rotation angle position of the wafer 10 illuminated by L3 (illumination range S3) is calculated. Accordingly, it is possible to accurately obtain the relationship between the detection data by the third detection unit 56 and the rotation angle position of the wafer 10 at that time without performing alignment separately.

  In addition, after performing the inspection in this manner, when performing another type of inspection on the same wafer 10 (for example, macro inspection on the surface of the wafer 10 or the like), the wafer 10 is rotated with respect to the rotation center of the wafer holder 23. Alignment is performed so that the center of the wafer 10 (rotation symmetry axis AX) coincides with the rotation center of the wafer holder 23 based on the eccentricity of the center (the eccentric amount and the eccentric direction).

  As a result, according to the surface inspection apparatus 1 according to the present embodiment, the arithmetic processing unit 70 operates the first and second edge detectors 30 and 40 based on the outputs from the pre-alignment sensors 61 to 63 ( The state of the variable apertures 34 and 44) and the output (position information of the light distribution) from the third edge detector 50 to the arithmetic processing unit 70 can be corrected, so that pre-alignment and inspection of the wafer 10 can be performed simultaneously. Therefore, the inspection time can be further shortened.

  Further, by detecting the vicinity of the edge of the wafer 10 based on the distribution of light detected by the detectors 36, 46, and 56 having a plurality of photodetectors, detection is performed by the detectors 36, 46, and 56. Since there is a lot of information on the light to be detected, it is possible to classify the detected abnormality. Further, since the light detection range is also widened, it is possible to cope with the deviation of the light distribution accompanying the eccentricity of the center of the wafer 10 (rotation symmetry axis AX).

  In addition, based on the outputs from the pre-alignment sensors 61 to 63, the arithmetic processing unit 70 sets each variable aperture so that the illumination positions of the oblique lights L1 and L2 with respect to the upper bevel portion 11 and the lower bevel portion 12 of the wafer 10 are constant. By driving and controlling 34 and 44, the illumination ranges (illumination positions and light amounts) of the oblique lights L1 and L2 in the upper bevel portion 11 and the lower bevel portion 12 are independent of the eccentricity of the center (rotation symmetry axis AX) of the wafer 10. Therefore, the inspection can be performed under the same conditions over the entire circumference of the wafer 10.

  In addition, the arithmetic processing unit 70 corrects the positional information of the light distribution detected by the third detection unit 56 based on the outputs from the pre-alignment sensors 61, 62, and 63, so that alignment is not performed separately. In addition, the relationship between the detection data by the third detection unit 56 and the rotation angle position of the wafer 10 at that time can be accurately obtained.

  Further, three sets of edge detectors and pre-alignment sensors are provided to detect the states of the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13 of the wafer 10. Inspection can be performed efficiently.

  Further, by using a line sensor as the pre-alignment sensor, the movement of the end portion of the wafer 10 can be detected at a high speed and in a wide range.

  In the above-described embodiment, each of the pre-alignment sensors 61 to 63 is disposed above the wafer 10 and detects the end of the wafer 10 from the front surface side of the wafer 10, but is not limited thereto. Instead, the end of the wafer 10 may be detected from the back side of the wafer 10 disposed below the wafer 10.

  In the above-described embodiment, three sets of edge detectors and pre-alignment sensors are provided to detect the states of the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13 of the wafer 10, respectively. The present invention is not limited, and one set of edge detectors and pre-alignment sensors may be provided to detect any one state of the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13. At this time, it is preferable that the edge detector and the pre-alignment sensor are arranged 180 degrees apart from each other with the rotational symmetry axis AX of the wafer 10 as the rotation axis. The position of the part can be detected with high sensitivity. Note that two sets of edge detectors and pre-alignment sensors may be provided to detect any two states of the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13.

  In the above-described embodiment, the operation state of the first and second edge detectors 30 and 40 and the arithmetic processing from the third edge detector 50 are detected while detecting the edge of the wafer 10 by the pre-alignment sensors 61 to 63. Although the output to the unit 70 is corrected, the present invention is not limited to this. The first and second rotations of the wafer 10 are detected after the detection by the pre-alignment sensors 61 to 63 at the first rotation of the wafer 10. The operation state of the second edge detectors 30 and 40 and the output from the third edge detector 50 to the arithmetic processing unit 70 may be corrected to inspect the wafer 10.

  In the above-described embodiment, the line sensor is used as the pre-alignment sensor. However, the present invention is not limited to this, and the end of the wafer 10 is detected using the first or second detection unit 36 or 46. It may be. For example, by using the first detection unit 36 having a plurality of photodetectors, the position of the specularly reflected light from the upper bevel portion 11 illuminated by the oblique light L1 by the first illumination unit 31 is detected. It is possible to detect the position of the end portion.

  Further, in the above-described embodiment, the vicinity of the end portion of the wafer 10 (the upper bevel portion 11, the lower bevel portion 12, and the apex portion 13) is inspected. However, the present invention is not limited to this. It is also possible to inspect the vicinity of the end.

It is a top view of a surface inspection apparatus. It is a side view of a surface inspection apparatus. It is a side view which shows the outer periphery edge part vicinity of a wafer. (A) is sectional drawing and bottom view of a 3rd test | inspection part, (b) is a figure which shows the state which the wafer moved with respect to (a). It is a figure which shows the positional relationship of the illumination range of the oblique light by a 1st and 2nd illumination part, and a wafer. It is a figure which shows the positional relationship of the illumination range of the oblique light by a 3rd illumination part, and a wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface inspection apparatus 10 Wafer 20 Wafer holding part (relative rotation part)
30 1st edge detector 31 1st illumination part 34 1st variable aperture 36 1st detection part 40 2nd edge detector 41 2nd illumination part 44 2nd variable aperture 46 2nd detection part 50 3rd edge detector 51 Third Illumination Unit 56 Third Detection Unit 59 Photodetector 61 First Prealignment Sensor 62 Second Prealignment Sensor 63 Third Prealignment Sensor 70 Arithmetic Processing Unit (Inspection Unit and Correction Unit)
L1 Oblique light L2 Oblique light L3 Oblique light AX Rotation symmetry axis

Claims (7)

An edge detector that detects a state near the edge of the substrate formed in a substantially disk shape, an inspection unit that performs an inspection near the edge of the substrate based on an output from the edge detector, and rotation of the substrate A relative rotation unit that rotates the substrate relative to the edge inspection device with a symmetry axis as a rotation axis, and the edge detector is in a state near the end of the substrate while performing the relative rotation by the relative rotation unit. In the surface inspection apparatus for detecting and inspecting the vicinity of the edge of the substrate based on the output from the edge detector by the inspection unit,
A pre-alignment sensor for detecting an end of the substrate;
And a correction unit that corrects at least one of the operation of the edge detector or the output from the edge detector to the inspection unit based on the output from the pre-alignment sensor. Surface inspection device. The edge detector illuminates the oblique light using an illumination unit that illuminates oblique light near the edge of the substrate and a plurality of light detectors arranged in a hemispherical shape so as to cover the edge of the substrate. And a detector for detecting the distribution of light from the vicinity of the edge of the substrate,
The surface inspection apparatus according to claim 1, wherein the inspection unit performs an inspection in the vicinity of an end portion of the substrate based on a distribution of the light output from the detection unit to the inspection unit. The edge detector is configured so that the illumination unit illuminates oblique light near an end portion on the front surface or the back surface of the substrate, and the detection unit detects a light distribution from the vicinity of the end portion on the front surface or the back surface of the substrate. Configured,
The illumination unit has a variable diaphragm capable of changing the illumination position of the oblique light,
The correction unit includes a drive control unit that drives and controls the variable diaphragm based on an output from the pre-alignment sensor so that the illumination position of the oblique light with respect to the vicinity of the end portion of the substrate is constant. The surface inspection apparatus according to claim 2. The edge detector is configured so that the illuminating unit illuminates oblique light on an end portion of the substrate from an extending direction of the substrate, and the detection unit detects a light distribution from the end portion of the substrate. And
The said correction | amendment part has a position correction | amendment part which correct | amends the positional information on the distribution of the said light detected by the said detection part based on the output from the said pre-alignment sensor. Surface inspection equipment.   5. The edge detector and the pre-alignment sensor are disposed at positions separated from each other by rotating 180 degrees about a rotational symmetry axis of the substrate as a rotation axis. The surface inspection apparatus described. The edge detector and the pre-alignment sensor are provided in three sets, and are arranged at predetermined angular intervals around the rotational symmetry axis of the substrate,
The first edge detector of the three sets of the edge detectors detects a state near the edge of the substrate from the surface side of the substrate,
The second edge detector of the three sets of the edge detectors detects a state in the vicinity of the edge of the substrate from the back side of the substrate,
The surface inspection apparatus according to claim 5, wherein a third edge detector of the three sets of the edge detectors detects a state in the vicinity of an end portion of the substrate from an extending direction of the substrate. .   The surface inspection apparatus according to claim 1, wherein the pre-alignment sensor is a line sensor that detects an end portion of the substrate from a front surface or a back surface side of the substrate.

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