Abstract:
A linear actuator which can make a bed flat in emergency. A linear actuator ( 10 ) comprising a shaft ( 16 ) having an externally threaded portion ( 17 ), a worm reduction gear for transmitting rotation of a motor ( 40 ) to the shaft ( 16 ), a nut ( 19 ) screwing on the externally threaded portion ( 17 ) and advancing or retreating as the shaft ( 16 ) rotates forward or reversely, and a moving tube ( 12 ) secured to the nut ( 19 ) and advancing or retreating for the housing ( 11 ) is further provided with a sub-shaft ( 52 ) interlocked with the worm reduction gear, an inner race ( 59 ) spline coupled with the sub-shaft ( 52 ), an engaging male portion ( 82 ) and an engaging female portion ( 83 ) interposed between the inner race ( 59 ) and the collar ( 55 ) of the shaft ( 16 ) to engage freely with each other, an operating ring ( 66 ) fitted rotatably to the outer circumference of the housing ( 11 ), and a working ring ( 72 ) for transmitting the rotation of the operating ring ( 66 ) to the inner race ( 59 ) while converting into axial movement. The shaft ( 16 ) can be rotated freely in emergency by disengaging the engaging male portion and the engaging female portion.

Description:
TECHNICAL FIELD 
     The present invention relates to an edge inspection apparatus and edge inspection method of a semiconductor wafer inspecting an outer circumference edge part of a semiconductor wafer. 
     BACKGROUND ART 
     In the past, a measurement apparatus (inspection apparatus) for measuring a cross-sectional shape of an outer circumference edge part of a semiconductor wafer has been proposed (see Patent Literature 1). This measurement apparatus projects light to the outer circumference edge part of a semiconductor wafer parallel to the surface of the semiconductor wafer and in its tangential direction, has the light passing the outer circumference edge part and proceeding via an optical system forming a telecentric structure received by an image sensor, and thereby forms a cross-sectional projection of the outer circumference edge part on the image sensor. Further, two-dimensional dimensions of the outer circumference edge part of the semiconductor wafer are measured from the image corresponding to the cross-sectional projection of the outer circumference edge part of the semiconductor wafer obtained based on the signal output from the image sensor. 
     According to such a measurement apparatus, the two-dimensional dimensions of the outer circumference edge part of the semiconductor wafer can be measured, so it is possible to inspect the suitability of the shape of the outer circumference edge part of the semiconductor wafer based on the measurement results. 
     In this regard, the outer circumference edge part of a semiconductor wafer is preferably inspected not only for the shape, but also for the presence of cracks, particles, or other defects at the outer circumference edge part. In the past, an inspection apparatus performing that type of inspection has been proposed (see Patent Literature 2). This inspection apparatus has a line sensor capturing an outer circumference end face of the outer circumference edge part of the semiconductor wafer, a line sensor capturing a slanted surface at an outer circumference rim of one surface of the semiconductor wafer, and a line sensor capturing a slanted surface at an outer circumference rim of the other surface of the semiconductor wafer. Further, using the shading distribution, color distribution, or other state of the outer circumference edge part of the semiconductor wafer obtained based on the signals detected from the line sensor, the presence of cracks, particles, or other defects at the outer circumference end face or slanted surfaces of the outer circumference edge part of the semiconductor wafer is judged. 
     According to this inspection apparatus, even the presence of defects of the outer circumference edge part of the semiconductor wafer which cannot be found by visual inspection can be precisely inspected. 
     Patent Literature 1: Japanese Patent Publication (A) No. 2006-145487 
     Patent Literature 2: Japanese Patent Publication (A) No. 2003-243465 
     SUMMARY OF INVENTION 
     Technical Problem 
     The inspection apparatus for inspecting the shape of an outer circumference edge part of a semiconductor wafer explained above projects light to the outer circumference edge part and measures two-dimensional dimensions from an image expressing its shadow (projection), so it cannot judge cracks, particles, or other defects from that image. For this reason, the inspection apparatus for inspecting the shape of the outer circumference edge part of a semiconductor wafer cannot share components (cameras etc.) or processing with an inspection apparatus for inspecting for cracks, particles, or other defects of that outer circumference edge part. As a result, it is difficult to perform the inspection of the shape of the outer circumference edge part of the semiconductor wafer and the inspection for the presence of cracks, particles, or other defects by the same process (same apparatus). 
     The present invention was made in consideration of this situation and provides an edge inspection apparatus and edge inspection method of a semiconductor wafer able to easily inspect the shape of an outer circumference edge part of a semiconductor wafer by the same process or same apparatus as the inspection for the presence of cracks, particles, or other defects of the outer circumference edge part. 
     Solution to Problem 
     The edge inspection apparatus of a semiconductor wafer according to the present invention is comprised having an imaging unit arranged facing the outer circumference edge part of the semiconductor wafer, successively capturing the outer circumference edge part in a circumferential direction, and outputting an image signal and an image processing unit processing the image signal successfully output from the imaging unit, the image processing unit having an image information generating means for generating image information expressing the outer circumference edge part of the semiconductor wafer from the image signal and a shape information generating means for generating edge shape information expressing shapes of a plurality of positions of the outer circumference edge part from the image information, designed to output inspection results based on the edge shape information. 
     Due to this configuration, image information expressing the outer circumference edge part of the semiconductor wafer is generated from an image signal from an imaging unit able to change in accordance with the state of cracks, particles, or other defects at the outer circumference edge part of the semiconductor wafer, so that image information can express the outer circumference edge part including the defects etc. Further, edge shape information expressing the shape of each of a plurality of positions of the outer circumference edge part is generated from that type of image information and inspection results based on that edge shape information are output. 
     The number of positions for generating the edge shape information of the outer circumference edge part of the semiconductor wafer is preferably as large as possible. By generating the edge shape information at more positions across the entire circumference of the outer circumference edge part of the semiconductor wafer, it becomes possible to more accurately evaluate the shape across the entire circumference of the outer circumference edge part from the inspection results based on that edge shape information. 
     The inspection results may be edge shape information corresponding to each position at the outer circumference edge part of the semiconductor wafer output in a predetermined format or may be some sort of evaluation information obtained from edge shape information of a plurality of positions of the outer circumference edge part. 
     Further, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that the imaging unit captures at least one of an outer circumference end face of the semiconductor wafer, a first outer circumference bevel surface slanted at an outer circumference rim of a first surface of the semiconductor wafer, and a second outer circumference bevel surface slanted at an outer circumference rim of a second surface at an opposite side from the first surface as the outer circumference edge part of the semiconductor wafer, and the shape information generating means generates at least one of information expressing the shape at each of a plurality of positions of the outer circumference end face from image information expressing an outer circumference end face of the semiconductor wafer, information expressing the shape at each of a plurality of positions of the first outer circumference bevel surface from image information expressing a first outer circumference bevel surface of the semiconductor wafer, and information expressing the shape at each of a plurality of positions of the second outer circumference bevel surface from image information expressing a second outer circumference bevel surface of the semiconductor wafer as the edge shape information. 
     The outer circumference edge part of a general semiconductor wafer has an outer circumference end face of the semiconductor wafer, a first outer circumference bevel surface slanted at an outer circumference rim of one surface of the semiconductor wafer (first surface), and a second outer circumference bevel surface slanted at an outer circumference rim of another surface of the semiconductor wafer (second surface). In this case, due to the configuration, it becomes possible to accurately evaluate the shapes of the surfaces from the inspection results based on edge shape information expressing the shapes at a plurality of positions of at least one of an outer circumference end face of the semiconductor wafer, first outer circumference bevel surface, and second outer circumference bevel surface. 
     Furthermore, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that the shape information generating means generates at least one of outer circumference end face length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the outer circumference end face from image information expressing the outer circumference end face, first outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the first outer circumference bevel surface from image information expressing the first outer circumference bevel surface, and second outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the second outer circumference bevel surface from image information expressing the second outer circumference bevel surface as the edge shape information. 
     Due to this configuration, it becomes possible to accurately perform any of evaluation of a length shape in a direction cutting across the circumferential direction of the outer circumference end face from the inspection results based on the outer circumference end face length information at a plurality of positions of the outer circumference end face of the semiconductor wafer, evaluation of a length shape in a direction cutting across the first outer circumference bevel surface from the inspection results based on first outer circumference bevel surface length information at a plurality of positions of the first outer circumference bevel surface of the semiconductor wafer, and evaluation of a length shape in a direction cutting across the second outer circumference bevel surface from the inspection results based on second outer circumferential bevel surface length information at a plurality of positions of the second outer circumference bevel surface of the semiconductor wafer. 
     Further, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that the shape information generating means generates outer circumference end face length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the outer circumference end face from image information expressing the outer circumference end face, first outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the first outer circumference bevel surface from image information expressing the first outer circumference bevel surface, and second outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential directions at each of a plurality of positions of the second outer circumference bevel surface from image information expressing the second outer circumference bevel surface and, based on the outer circumference surface length information, the first outer circumference bevel surface length information, and the second outer circumference bevel surface length information, generates at least one of first outer circumference bevel surface angle information expressing a slant angle at each of said plurality of positions of the first outer circumference bevel surface, second outer circumference bevel surface angle information expressing a slant angle at each of said plurality of positions of the second outer circumference bevel surface, first outer circumference bevel surface diametrical direction component length information expressing a length component in a diametrical direction of the semiconductor wafer at each of the plurality of positions of the first outer circumference bevel surface, second outer circumference bevel surface diametrical direction component length information expressing a length component in the diametrical direction at each of the plurality of positions of the second outer circumference bevel surface, first outer circumference bevel surface axial direction component length information expressing a length component in an axial direction vertical to the semiconductor wafer at each of the plurality of positions of the first outer circumference bevel surface, and second outer circumference bevel surface axial direction component length information expressing a length component in the axial direction at each of the plurality of positions of the second outer circumference bevel surface as the edge shape information. 
     Due to this configuration, it becomes possible to accurately evaluate a shape relating to a slant angle of the first outer circumference bevel surface from inspection results based on first outer circumference bevel surface angle information at a plurality of positions of a first outer circumference bevel surface of the semiconductor wafer, evaluate a shape relating to a slant angle of the second outer circumference bevel surface from inspection results based on second outer circumference bevel surface angle information at a plurality of positions of a second outer circumference bevel surface of the semiconductor wafer, and evaluate a shape relating to a length component in a diametrical direction of the semiconductor wafer of the first outer circumference bevel surface from inspection results based on first outer circumference bevel surface diametrical direction component length information at a plurality of positions of the first outer circumference bevel surface, a shape relating to a length component in a diametrical direction of the semiconductor wafer of the second outer circumference bevel surface from inspection results based on second outer circumference bevel surface diametrical direction component length information at a plurality of positions of the second outer circumference bevel surface, a shape relating to a length component in the axial direction of the first outer circumference bevel surface from inspection results based on first outer circumference bevel surface axial direction length information at a plurality of positions of the first outer circumference bevel surface, and a shape relating to a length component in the axial direction of the second outer circumference bevel surface from inspection results based on second outer circumference bevel surface axial direction length information at a plurality of positions of the second outer circumference bevel surface. 
     Further, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that it outputs inspection results based on at least one of a maximum value, minimum value, average value, and standard deviation of a value of edge shape information at each of the plurality of positions based on edge shape information expressing a shape at each of a plurality of positions of the outer circumference edge part. 
     Further, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that it outputs inspection results based on at least one of a maximum value, minimum value, average value, and standard deviation of a value of at least one of the outer circumference end face length information, the first outer circumference bevel surface length information, and the second outer circumference bevel surface length information at each of the plurality of positions of the outer circumference edge part. 
     Furthermore, in the edge inspection apparatus of a semiconductor wafer according to the present invention, the apparatus may be configured so that it outputs inspection results based on at least one of a maximum value, minimum value, average value, and standard deviation of a value of at least one of first outer circumference bevel surface angle information, second outer circumference bevel surface angle information, first outer circumference bevel surface diametrical direction component length information, second outer circumference bevel surface diametrical direction component length information, first outer circumference bevel surface axial direction component length information, and second outer circumference bevel surface axial direction component length information at each of a plurality of positions of the outer circumference edge part. 
     Due to the above-mentioned configuration, it becomes possible to use inspection results of at least one of the maximum value, minimum value, average value, and standard deviation of a value of edge shape information at a plurality of positions of the outer circumference edge part of the semiconductor wafer so as to easily manage the trends in shape of that outer circumference edge part in the process of production of a semiconductor wafer  100 . 
     The edge inspection method of a semiconductor wafer according to the present invention has an edge capturing step using an imaging unit arranged facing an outer circumference edge part of a semiconductor wafer to capture an outer circumference edge part and an image processing step processing an image signal capturing the outer circumference edge part of the semiconductor wafer successively output from the imaging unit, the image processing step having an image information generating step generating image information expressing the outer circumference edge part of the semiconductor wafer from the image signal and a shape information generating step generating edge shape information expressing an edge shape at each of a plurality of positions of the outer circumference edge part from the image information, so as to obtain inspection results based on the edge shape information. 
     Further, in the edge inspection method of a semiconductor wafer as set forth in the present invention, the method may be configured so that the edge capturing step uses the imaging unit to capture at least one of an outer circumference end face of the semiconductor wafer, a first outer circumference bevel surface slanted at an outer circumference rim of a first surface of the semiconductor wafer, and a second outer circumference bevel surface slanted at an outer circumference rim of a second surface at an opposite side from the first surface as the outer circumference edge part of the semiconductor wafer, and the shape information generating step generates at least one of information expressing a shape at each of a plurality of positions of the outer circumference end face from image information expressing an outer circumference end face of the semiconductor wafer, information expressing a shape at each of a plurality of positions of the first outer circumference bevel surface from image expressing a first outer circumference bevel surface of the semiconductor wafer, and information expressing a shape at each of a plurality of positions of the second outer circumference bevel surface from image information expressing a second outer circumference bevel surface of the semiconductor wafer as the edge shape information. 
     Furthermore, in the edge inspection method of a semiconductor wafer according to the present invention, the method may be configured so that the shape information generating step generates at least one of outer circumference end face length information expressing a length of a direction cutting across the circumferential direction at each of a plurality of positions of the outer circumference end face from image information expressing the outer circumference end face, first outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the first outer circumference bevel surface from image information expressing the first outer circumference bevel surface, and second outer circumference bevel surface length information expressing a length in a direction cutting across the circumferential direction at each of a plurality of positions of the second outer circumference bevel surface from image information expressing the second outer circumference bevel surface as the edge shape information. 
     Advantageous Effects of the Invention 
     According to the edge shape inspection apparatus and edge inspection method according to the present invention, image information generated from an image signal output from an imaging unit capturing an outer circumference edge part of a semiconductor wafer can express cracks, particles, or other defects of the outer circumference edge part. Edge shape information expressing the shape of the outer circumference edge part is generated from that type of image information, so it becomes possible to easily inspect the shape of an outer circumference edge part of a semiconductor wafer by the same process or same apparatus as inspection for the presence of cracks, particles, or other defects at the outer circumference edge part based on the image information. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  A perspective view showing the appearance of a semiconductor wafer to be inspected by an edge inspection apparatus according to an embodiment of the present invention. 
         FIG. 1B  A cross-sectional view along the line A-A of  FIG. 1A . 
         FIG. 2  A view schematically showing main parts of an imaging system of an edge inspection apparatus according to an embodiment of the present invention. 
         FIG. 3  A block diagram schematically showing main parts of a control system of an edge inspection apparatus according to an embodiment of the present invention. 
         FIG. 4  A view schematically showing another example of the configuration of an imaging system of an edge inspection apparatus. 
         FIG. 5  A flowchart showing a processing routine in a processing unit in the control system shown in  FIG. 3  (part  1 ). 
         FIG. 6  A flowchart showing a processing routine in a processing unit in the control system shown in  FIG. 3  (part  2 ). 
         FIG. 7  A view for explaining an angular position of a semiconductor wafer. 
         FIG. 8  A view showing an example of a display image of a first outer circumference bevel surface (a) and a change in shading of that image at an angular position θ (b). 
         FIG. 9  A view showing an example of a display image of an outer circumference end face (a) and a change in shading of that image at an angular position θ (b). 
         FIG. 10  A view showing an example of a display image of a second outer circumference bevel surface (a) and a change in shading of that image at an angular position θ (b). 
         FIG. 11  A view showing an example of output of first outer circumference bevel surface length data Ub(θ) as inspection results. 
         FIG. 12  A view showing an example of output of outer circumference end face length data Ap(θ) as inspection results. 
         FIG. 13  A view showing an example of output of second outer circumference bevel surface length data Lb(θ) as inspection results. 
         FIG. 14A  A view showing an example of output of first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ) as inspection results. 
         FIG. 14B  A view showing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a first approximation value in the total angular range of each of the first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ). 
         FIG. 15A  A view showing an example of the cross-sectional shape of the outer circumference edge part of the semiconductor wafer. 
         FIG. 15B  A view showing another example of the cross-sectional shape of the outer circumference edge part of the semiconductor wafer. 
         FIG. 16  A view showing an example of edge shape information able to express the shape of an outer circumference edge part. 
         FIG. 17  A view showing an example of output of first outer circumference bevel surface angle data α 1 (θ) as inspection results. 
         FIG. 18  A view showing an example of output of second outer circumference bevel surface angle data α 2 (θ) as inspection results. 
         FIG. 19  A view showing another example of output of first outer circumference bevel surface angle data α 1 (θ) as inspection results. 
         FIG. 20  A view showing an initial approximation value at each angular position θ of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data). 
         FIG. 21A  A view showing a first approximation value at each angular position θ of each of A 1  (first outer circumference bevel surface diametrical direction component length data) and A 2  (second outer circumference bevel surface diametrical direction component length data). 
         FIG. 21B  A view showing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a first approximation value in the total angular range of each of A 1  (first outer circumference bevel surface diametrical direction component length data) and A 2  (second outer circumference bevel surface diametrical direction component length data). 
         FIG. 22A  A view showing a first approximation value at each angular position θ of each of α 1  (first outer circumference bevel surface angle data) and α 2  (second outer circumference bevel surface angle data). 
         FIG. 22B  A view showing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a first approximation value at the total angular range of each of α 1  (first outer circumference bevel surface angle data) and α 2  (second outer circumference bevel surface angle data). 
         FIG. 23  A view showing the case when hypothesizing the value at each angular position θ of each of α 1  (first outer circumference bevel surface angle data) and α 2  (second outer circumference bevel surface angle data) to be an average values of first approximation values. 
         FIG. 24A  A view expressing the first approximation value at each angular position θ of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data). 
         FIG. 24B  A view expressing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a first approximation value at the total angular range of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data). 
         FIG. 25A  A view expressing a second approximation value at each angular position θ of each of A 1  (first outer circumference bevel surface diametrical direction component length data) and A 2  (second outer circumference bevel surface diametrical direction component length data). 
         FIG. 25B  A view expressing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a second approximation value at the total angular range of each of A 1  (first outer circumference bevel surface diametrical direction component length data) and A 2  (second outer circumference bevel surface diametrical direction component length data). 
         FIG. 26  A view of the case when hypothesizing the value at each angular position θ of each of A 1  (first outer circumference bevel surface diametrical direction component length data) and A 2  (second outer circumference bevel surface diametrical direction component length data) to be an average value of the second approximation values. 
         FIG. 27A  A view expressing a second approximation value at each angular position θ of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data). 
         FIG. 27B  A view expressing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a second approximation value at the total angular range of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data). 
         FIG. 28A  A view expressing a second approximation value at each angular position θ of each of α 1  (first outer circumference bevel surface angle data) and α 2  (second outer circumference bevel surface angle data). 
         FIG. 28B  A view expressing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a second approximation value at the total angular range of each of α 1  (first outer circumference bevel surface angle data) and α 2  (second outer circumference bevel surface angle data). 
         FIG. 29A  A view expressing a value at an angular position θ corresponding to a thickness T of a semiconductor wafer in the case when hypothesizing that the value at each angular position θ of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data) is an n-th approximation value. 
         FIG. 29B  A view expressing a maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of a second approximation value in the total angular range of a thickness T of the semiconductor wafer when hypothesizing that the value at each angular position θ of each of B 1  (first outer circumference bevel surface axial direction component length data) and B 2  (second outer circumference bevel surface axial direction component length data) is an n-th approximation value. 
     
    
    
     REFERENCE SIGNS LIST 
     
         
         
           
               10  CCD camera 
               10   a  first CCD camera 
               10   b  second CCD camera 
               10   c  third CCD camera 
               11  camera lens 
               12  camera body 
               20  processing unit 
               31  first mirror 
               32  second mirror 
               33  correction lens 
               40  display unit 
               50  rotation drive motor 
               51  turntable 
               100  semiconductor wafer 
               101  outer circumference edge part 
               101   a  outer circumference end face 
               101   b  first outer circumference bevel surface 
               101   c  second outer circumference bevel surface 
               102  notch 
           
         
       
    
     DESCRIPTION OF EMBODIMENTS 
     Below, embodiments of the present invention will be explained using the drawings. 
     A silicon semiconductor wafer to be inspected by an edge inspection apparatus according to an embodiment of the present invention is structured as shown in  FIG. 1A  and  FIG. 1B . Note that,  FIG. 1A  is a perspective view of a semiconductor wafer, while  FIG. 1B  is a cross-sectional view along the line A-A of  FIG. 1A . As shown in  FIG. 1A  and  FIG. 1B , an outer circumference edge part  101  of a disk-shaped semiconductor wafer  100  is comprised of an outer circumference end face  101   a  of the semiconductor wafer  100 , a first outer circumference bevel surface  101   b  slanted at an outer circumference rim of one surface of the semiconductor wafer  100  (first surface), and a second outer circumference bevel surface  101   c  slanted at an outer circumference rim of another surface of the semiconductor wafer  100 . At that outer circumference edge part  101 , a notch  102  is formed expressing a reference position in the circumferential direction (Ds). 
     The basic configuration of the imaging system in an edge inspection apparatus according to an embodiment of the present invention becomes as shown in  FIG. 2 . Note that, the configuration of the mechanical system of this edge inspection apparatus as a whole may, for example, be made similar to that described in the Patent Literature 2. 
     In  FIG. 2 , the semiconductor wafer  100  configured as explained above (see  FIG. 1A  and  FIG. 1B ) is, for example, set on a turntable (not shown in  FIG. 2 ) and can turn together with that turntable about its rotational shaft Lc. Facing the outer circumference edge part  101  of the semiconductor wafer  100  set on the turntable, an imaging unit comprised of three CCD cameras, that is, a first CCD camera  10   a , second C=D camera  10   b , and third CCD camera  10   c , is set. The first CCD camera  10   a  faces the outer circumference end face  101   a  of the semiconductor wafer  100 . A CCD line sensor  11   a  inside it is set to an orientation so as to extend in a direction (Da) cutting across the outer circumference end face  101   a  substantially perpendicularly to its circumferential direction (Ds: direction vertical to paper surface of  FIG. 2 ). The second CCD camera  10   b  faces the first outer circumference bevel surface  101   b  of the semiconductor wafer  100 . A CCD line sensor  11   b  inside it is set to an orientation so as to extend in a direction (Db) cutting across the first outer circumference bevel surface  101   b  substantially perpendicularly to its circumferential direction (Ds). The third CCD camera  10   c  faces the second outer circumference bevel surface  101   c  of the semiconductor wafer  100 . A CCD line sensor  11   c  inside it is set to an orientation so as to extend in a direction (Dc) cutting across the second outer circumference bevel surface  101   c  substantially perpendicularly to its circumferential direction (Ds). 
     In the process of the semiconductor wafer  100  turning, the CCD line sensor  11   a  of the first CCD camera  10   a  successively scans that outer circumference end face  101   a  in the circumferential direction (Ds) (sub scan). Due to this, the first CCD camera  10   a  successively captures the outer circumference end face  101   a  in the circumferential direction (Ds) and outputs an image signal in pixel units. Further, in that process, the CCD line sensor  11   b  of the second CCD camera  10   b  successively scans the first outer circumference bevel surface  101   b  of the semiconductor wafer  100  in the circumferential direction (Ds) (sub scan) and the CCD line sensor  11   c  of the third CCD camera  10   c  successively scans the second outer circumference bevel surface  101   c  in the circumferential direction (Ds) (sub scan). Due to this, the second CCD camera  10   b  captures the first outer circumference bevel surface  101   b  and the third CCD camera  10   c  captures the second outer circumference bevel surface  101   c  in the circumferential direction (Ds) and output image signals in pixel units. 
     A control system of an edge inspection apparatus according to an embodiment of the present invention is configured as shown in  FIG. 3 . 
     In  FIG. 3 , the first CCD camera  10   a , second CCD camera  10   b , and third CCD camera  10   c  are connected to a processing unit  20  formed by a computer. The processing unit  20  controls the drive of a rotation drive motor  50  so as to turn a turntable  51  on which a semiconductor wafer  100  is set in a horizontal state by an alignment mechanism at a predetermined speed and processes image signals successively output from the first CCD camera  10   a , second CCD camera  10   b , and third CCD camera  10   c . Further, the processing unit  20  is connected to a display unit  40 . The processing unit  20  displays images based on image information generated from the image signals, information expressing inspection results obtained by processing the image information, etc. on the display unit  40 . 
     Note that, the imaging unit capturing the outer circumference edge part  101  of the semiconductor wafer  100  need not be configured by three CCD cameras  10   a ,  10   b , and  10   c . For example, as shown in  FIG. 4 , it may also be configured by a single CCD camera  10 . In this case, near the first outer circumference bevel surface  101   b  at the outer circumference edge part  101  of the semiconductor wafer  100 , a first mirror  31  is set, while near the second outer circumference bevel surface  101   c , a second mirror  32  is set. The slants of the first mirror  31  and second mirror  32  are set so that the direction in which the image of the first outer circumference bevel surface  101   b  reflected at the first mirror  31  is led and the direction in which the image of the second outer circumference bevel surface  101   c  reflected at the second mirror  32  is led become parallel. 
     The CCD camera  10  has a camera lens  11  and a camera body  12 . The camera body  12  is provided with a CCD line sensor and is designed so that an image led through the camera lens  11  is formed on that CCD line sensor. The cm camera  10  has a visual field including the outer circumference edge part  101  of the semiconductor wafer  100  and is arranged at a position where the image of the first outer circumference bevel surface  101   b  and the image of the second outer circumference bevel surface  101   c  led through the first mirror  31  and second mirror  32  are focused on the imaging surface of the CCD line sensor. 
     The image of the outer circumference end face  101   a  of the semiconductor wafer  100  passes through the camera lens  11  of the CCD camera  10  and is formed on the imaging surface of the CCD line sensor in the camera body  12 . In this case, the optical path length from the first outer circumference bevel surface  101   b  (second outer circumference bevel surface  101   c ) through the first mirror  31  (second mirror  32 ) to the camera unit  10  and the optical path length from the outer circumference end face  101   a  to the camera unit  10  differ, so as that is, the image of the outer circumference end face  101   a  will not be focused on the imaging surface of the camera body  12 . Therefore, between the outer circumference end face  101   a  of the semiconductor wafer  100  and the CCD camera  10 , a correction lens  33  is set. This correction lens  33  and camera lens  11  are used to guide the image of the outer circumference end face  101   a  of the semiconductor wafer  100  so as to be focused on the imaging surface of the CCD line sensor in the camera body  12 . 
     In this way, the optical system arranged between the CCD camera  10  and the outer circumference edge part  101  of the semiconductor wafer  100  (first mirror  31 , second mirror  32 , and correction lens  33 ) is used so that the images of the outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c  of the outer circumference edge part  101  are focused on the imaging surface of the CCD line sensor of the CCD camera  10 . Due to this, the image signals successively output from the CCD camera  10  express the different parts of the outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c.    
     The processing unit  20  executes processing in accordance with the routine shown in  FIG. 5  and  FIG. 6 . 
     In  FIG. 5 , the processing unit  20  makes the turntable  51  on which the semiconductor wafer  100  is set turn by a predetermined speed (S 1 ). In the process of the semiconductor wafer  100  turning, the processing unit  20  receives as input image signals successively output from the first CCD camera  10   a , second CCD camera  10   b , and third CCD camera  10   c , generates image information expressing the outer circumference edge part  101  of the semiconductor wafer  100  from these image signals (for example, shading data represented in predetermined gradation for each pixel), and stores that image information (image data) in a predetermined memory (not shown) (S 2 ). Specifically, from the image signal from the first CCD camera  10   a , as shown in  FIG. 7 , image data I AP (θ) expressing the outer circumference end face  101   a  of the semiconductor wafer  100  at each angular position θ in the circumferential direction (Ds) from the notch  102  (θ=0°) (for example, by an angular resolution corresponding to the width of the CCD line sensor  11   a ) is generated, from the image signal from the second CCD camera  10   b , image data I Ub (θ) expressing the first outer circumference bevel surface  101   b  of the semiconductor wafer  100  at each angular position θ is generated, from the image signal from the third CCD camera  10   c , image data I Lb (θ) expressing the second outer circumference bevel surface  101   c  of the semiconductor wafer  100  at each angular position θ is generated, and these image data I AP (θ), I Ub (θ), and I Lb (θ) are stored in the memory in a state linked with the angular position θ. 
     The processing unit  20 , in the process of the processing, judges if one turn&#39;s worth of image data of the semiconductor wafer  100  has finished being fetched (stored in the memory) (S 3 ). When one turn&#39;s worth of image data of the semiconductor wafer  100  has finished being fetched (YES at S 3 ), the processing unit  20  stops the turning of the turntable  51  on which the semiconductor wafer  100  is set (S 4 ). After this, it performs processing for image display based on the fetched image data I AP (θ), I Ub (θ), and I Lb (θ) (S 5 ) and ends the series of processing. 
     Note that, when using a single CCD camera  10  as shown in  FIG. 4 , the processing unit  20  cuts out from the image signals from the CCD camera  10  the signal part corresponding to the outer circumference end face  101   a , the signal part corresponding to the first outer circumference bevel surface  101   b , and the signal part corresponding to the second outer circumference bevel surface  101   c  to generate from the signal parts the image data I AP (θ), I Ub (θ), and I Lb (θ) expressing the outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c.    
     Due to the processing for image display (S 5 ), based on the image data I Ub (θ) expressing the first outer circumference bevel surface  101   b  of one turn of the semiconductor wafer  100 , for example, as shown in  FIG. 8(   a ), the image I(Ub) of the first outer circumference bevel surface  101   b  in the visual field Eb of the second CCD camera  10   b  is displayed on the display unit  40 . Further, based on the image data I AP (θ) expressing the outer circumference end face  101   a  of one turn of the semiconductor wafer  100 , for example, as shown in  FIG. 9(   a ), the image I(Ap) of the outer circumference end face  101   a  in the visual field Ea of the first CCD camera  10   a  is displayed on the display unit  40 , furthermore, based on the image data I Lb (θ) expressing the second outer circumference bevel surface  101   c  of one turn of the semiconductor wafer  100 , for example, as shown in  FIG. 10(   a ), the image I(Lb) of the second outer circumference bevel surface in the visual field Ec of the third CCD camera  10   c  is displayed on the display unit  40 . 
     Note that, display unit  40  can be made to display the screen by scrolling in a case where all of the images of one turn of the semiconductor wafer for the first outer circumference bevel surface  101   b , outer circumference end face  101   a , and second outer circumference bevel surface  101   c  cannot be displayed all together. 
     As shown in  FIG. 8(   a ),  FIG. 9(   a ), and  FIG. 10(   a ), the images I(Ub), I(AP), and I(Lb) of the first outer circumference bevel surface  101   b , outer circumference end face  101   a , and second outer circumference bevel surface  101   c  displayed on the display unit  40  can express cracks, particles, or other defects d 2 , d 1 , and d 3 . By observing the images displayed on such a display unit  40 , it is possible to inspect at what positions of the outer circumference edge part  101  of the semiconductor wafer  100  (first outer circumference bevel surface  101   b , outer circumference end face  101   a , and second outer circumference bevel surface  101   c ) (angular position θ from the notch  102 ) there are defects. 
     The processing unit  20  responds to a predetermined operation at the operation unit (not shown) and performs processing relating to shape inspection of the outer circumference edge part  101  of the semiconductor wafer  100  in accordance with the routine shown in  FIG. 6 . 
     In  FIG. 6 , the processing unit  20  sets the angular position θ at an initial value (for example, θ=0°) (S 11 ) and reads out three types of image data I AP (θ), I Ub (θ), and I Lb (θ) (S 12 ) stored in the memory as explained above in response to this angular position θ. Further, the processing unit  20  generates edge shape information expressing the shape of the first outer circumference bevel surface  101   b  at the angular position θ based on image data I Ub (θ) expressing the first outer circumference bevel surface  101   b  (S 13 ). Specifically, as shown in  FIG. 8 , based on the state of change (change of shading) of the image data I Ub (θ) at the angular position θ (see  FIG. 8(   b )), the boundaries of the image I(Ub) of the first outer circumference bevel surface  101   b  are detected and the first outer circumference bevel surface length data Ub(θ) expressed by the number of pixels between the image boundaries (or converted to distance by the pitch of pixels of the CCD line sensor  11   b ) is generated as edge shape information. This first outer circumference bevel surface length data Ub(θ) expresses the length in a direction cutting across the circumferential direction (Ds) at the angular position θ of the first outer circumference bevel surface  101   b  approximately perpendicularly (see  FIG. 8(   a )). 
     The processing unit  20  similarly generates edge shape information expressing the outer circumference end face  101   a  and edge shape information expressing the shape of the second outer circumference bevel surface  101   c  (S 13 ). Specifically, as shown in  FIG. 9 , based on the state of change of the image data I AP (θ) at the angular position θ (change of shading) (see  FIG. 9(   b )), the boundaries of the image I(Ap) of the outer circumference end face  101   a  are detected and the outer circumference end face length data Ap(θ) expressed by the number of pixels between the image boundaries is generated as edge shape information. This outer circumference end face length data Ap(θ) expresses a length in a direction cutting across the circumferential direction (DS) of the outer circumference end face  101   a  at the angular position θ approximately perpendicularly (see  FIG. 9(   a )). Further, for the shape of the second outer circumference bevel surface  101   c , as shown in  FIG. 10 , based on the state of change (change of shading) of the image data I Lb (θ) at the angular position θ (see  FIG. 10(   b )), the boundaries of the image I(Lb) of the second outer circumference bevel surface  101   c  are detected and second outer circumference bevel surface length data Lb(θ) expressed by the number of pixels between the image boundaries is generated as the edge shape information. This second outer circumference bevel surface length data Lb(θ) expresses the length of a direction cutting across the circumferential direction (Ds) at the angular position θ of the second outer circumference bevel surface  101   c  approximately perpendicularly (see  FIG. 10(   a )). 
     Returning to  FIG. 6 , the processing unit  20  stores the first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ) as edge shape information of the angular position θ generated in the above way in a predetermined memory linked with the angular position θ (S 14 ). After this, the processing unit  20  judges if the angular position θ has reached 360° (θ=360°) (S 15 ). If the angular position θ does not reach 360° (NO at S 15 ), it judges that the processing for one turn of the semiconductor wafer  100  is not ended and increases the angular position θ by exactly the amount of a predetermined angle Δθ (θ=θ+Δθ:S 16 ). Further, the processing unit  20  performs similarly processing again as the above-mentioned processing for that new angular position θ (S 12  to S 16 ). Due to this, the first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ) at the new angular position θ are stored in a predetermined memory linked with that angular position θ (S 14 ). 
     When it is judged that the angular position θ has reached 360° (YES at S 15 ), it is judged that the processing of one turn of the semiconductor wafer  100  has ended. The processing unit  20  executes output processing (S 17 ) and ends the series of processing. 
     By the above output processing, for example, graphs where the first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ) generated as explained above are plotted corresponding to a plurality of angular positions θ are displayed as inspection results on the display unit  40 . For a certain semiconductor wafer  100 , a graph where the first outer circumference bevel surface length data Ub(θ) is plotted so as to correspond to the angular position θ is displayed as the broken line Q 11  (solid line) or the broken line Q 21  (dotted line) of  FIG. 11 , a graph where the outer circumference end face length data Ap(θ) is plotted so as to correspond to the angular position θ is displayed as the broken line Q 12  (solid line) or the broken line Q 22  (dotted line) of  FIG. 12 , and, further, a graph where the second outer circumference bevel surface length data Lb(θ) is plotted to correspond to the angular position θ is displayed as the broken line Q 13  (solid line) or the broken line Q 23  (dotted line) of  FIG. 13 . For example, from the broken lines Q 11 , Q 12 , and Q 13 , at the semiconductor wafer  100  being inspected, the outer circumference end face length Ap (see broken line Q 12 ) is stable over the entire circumference, but it is learned that the first outer circumference bevel surface length Ub (see broken line Q 11 ) and second outer circumference bevel surface length Lb (broken line Q 13 ) fluctuate relatively largely at the angular position range θ=90° to 180°. From this, the semiconductor wafer  100  being inspected can be evaluated as changing in shape relatively largely at the first outer circumference bevel surface  101   b  and second outer circumference bevel surface  101   c  at the angular position range 90° to 180° compared with other angular position ranges. This evaluation result can be utilized as useful information in the next processing step such as processing for forming a film on the semiconductor wafer  100 . Further, in the previous processing step for forming the outer circumference edge part  101  of the semiconductor wafer  100  (outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c ) as well, the evaluation result can be utilized as useful information. 
     Note that, the outer circumference end face length data Ap(θ), first outer circumference bevel surface length data Ub(θ), and second outer circumference bevel surface length data Lb(θ) at each angular position θ may, as shown in  FIG. 14A , be graphed all together for output as inspection results. Further, the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of Ap, Ub, and Lb at the total angular position range (0° to 360°) may, for example, as shown in  FIG. 14B , be tabularized for output as inspection results. 
     When graphing all together the outer circumference end face length data Ap(θ), first outer circumference bevel surface length data Ub(θ), and second outer circumference bevel surface length data Lb(θ) corresponding to each angular position θ for display (output) as the inspection results, it becomes possible to visually judge the shape of the outer circumference edge part (outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c ) of the semiconductor wafer  100  based on the shape of the graph. Further, when tabularizing the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of the Ap, Ub, and Lb at the total angular position range (0° to 360°) for display (output) as inspection results, in the production process of a semiconductor wafer  100 , it becomes possible to easily manage the trends in the shape of the outer circumference edge part of a semiconductor wafer  100  based on the trends in these statistical values. 
     Note that, for example, as shown in  FIG. 15A  and  FIG. 15B , even when the cross-sectional shape of the outer circumference edge part  101  is curved, image data corresponding to the outer circumference end face  101   a , first outer circumference bevel surface  101   a , and second outer circumference bevel surface  101   c  as shown by the dotted line is obtained. Therefore, even when the cross-sectional shape of the outer circumference edge part  101  is curved in this way, in the same way as explained above, the first outer circumference bevel surface length data Ub(θ), outer circumference end face length data Ap(θ), and second outer circumference bevel surface length data Lb(θ) at the plurality of angular positions θ can be used to evaluate the external shape of the outer circumference edge part  101  of the semiconductor wafer  100 . 
     The edge inspection apparatus such as explained above is particularly effective for determining the trends in the overall shape of the outer circumference edge part  101  for each semiconductor wafer  100  (individual specimen). 
     As explained above, the image data I Ap (θ), I Ub (θ), and I Lb (θ) generated from the image signals output from the first CCD camera  10   a , second CCD camera  10   c , and third CCD camera  10   b  capturing the outer circumference edge part  101  of the semiconductor wafer  100  can express cracks, particles, or other defects dl, d 2 , and d 3  of the outer circumference end face  101   a , first outer circumference bevel surface  101   b , and second outer circumference bevel surface  101   c  at the outer circumference edge part  101 . Therefore, in the edge inspection apparatus, from that type of image data I AP (θ), I Ub (θ), and I Lb (θ), as the edge shape information expressing the shape of the outer circumference edge part  101 , the outer circumference end face length data Ap(θ) expressing the shape of the outer circumference end face  101   a , the first outer circumference bevel surface length data Ub(θ) expressing the shape of the first outer circumference bevel surface  101   b , and the second outer circumference bevel surface length data Lb(θ) expressing the shape of the second outer circumference bevel surface  101   c  are generated, so it becomes possible to easily inspect the shape of the outer circumference edge part  101  by the same process or same apparatus as the inspection for the presence of cracks, particles, or other defects dl, d 2 , and d 3  at the outer circumference edge part  101  based on the image data I AP (θ), I Ub (θ), and I Lb (θ) (see  FIG. 8 ,  FIG. 9 , and  FIG. 10 ). 
     In the above-mentioned example, as the edge shape information expressing the shape of the outer circumference edge part  101  of the semiconductor wafer  100 , outer circumference end face length data Ap(θ) expressing a length in a direction cutting across the circumferential direction at a plurality of angular positions θ of the outer circumference end face  101   a  approximately perpendicularly, first outer circumference bevel surface length data Ub(θ) expressing a length of a direction cutting across the circumferential direction at a plurality of angular positions θ of the first outer circumference bevel surface  101   b  approximately perpendicularly, and second outer circumference bevel surface length data Lb(θ) expressing the length in a direction cutting across the circumferential direction at a plurality of angular positions θof the second outer circumference bevel surface  101   c  approximately perpendicularly were used, but that edge shape information may also be one or more of these or may be other information. For example, as shown in  FIG. 16 , at least one of first outer circumference bevel surface angle data α 1  expressing a slant angle at each of a plurality of angular positions θof the first outer circumference bevel surface  101   b , second outer circumference bevel surface angle data α 2  expressing a slant angle at each of a plurality of angular positions θof the second outer circumference bevel surface  101   c , first outer circumference bevel surface diametrical direction component length data Al expressing a length component in the diametrical direction of the semiconductor wafer  100  at each of a plurality of angular positions θof the first outer circumference bevel surface  101   b , second outer circumference bevel surface diametrical direction component length data A 2  expressing a length component in the diametrical direction at each of a plurality of angular positions θ of the second outer circumference bevel surface  101   c , first outer circumference bevel surface axial direction component length data B 1  expressing a length component in the axial direction vertical to the semiconductor wafer  100  at each of a plurality of angular positions θ of the first outer circumference bevel surface  101   b , and second outer circumference bevel surface axial direction component length data B 2  expressing a length component in the axial direction at each of a plurality of angular positions θ of the second outer circumference bevel surface  101   c  may be generated as the edge shape information. 
     The first outer circumference bevel surface angle data α 1 , second outer circumference bevel surface angle data α 2 , first outer circumference bevel surface diametrical direction component length data A 1 , second outer circumference bevel surface diametrical direction component length data A 2 , first outer circumference bevel surface axial direction component length data B 1 , and second outer circumference bevel surface axial direction component length data B 2 , as explained above, may be calculated in accordance with various techniques from the outer circumference surface length data Ap(θ), first outer circumference bevel surface length data Ub(θ), and second outer circumference bevel surface length data Lb(θ) generated from the image data I AP (θ) I Ub (θ), and I Lb (θ) (see  FIG. 16 ). 
     For example, in  FIG. 16 ,
 
 Ub=A 1/cos α1  (1)
 
 B 1= Ub ·sin α1  (2)
 
where,
 
 B 1= B 2=( T−Ap )/2  (3)
 
is hypothesized. Note that, T is the thickness of the semiconductor wafer  100  (for example, T=755 μm).
 
     As explained above, for each of a plurality of (for example, 10) semiconductor wafers  100  for which the Ap (outer circumference surface length data), Ub (first outer circumference bevel surface length data), and Lb (second outer circumference bevel surface length data) have already been generated from the image data, first outer circumference bevel surface axial direction component length data B 1  (i) at a certain angular position θ is calculated in accordance with the equation (3) (i is a number identifying the semiconductor wafer  100 , i=1, . . . 10). 
     Further, the average value B 1 ave of that B 1 ( 1 ), B 1 ( 2 ), . . . , B 1 ( 10 ) is calculated in accordance with
 
 B 1ave={ B 1(1)+ B 1(2)+ . . . + B 1(10)}/10  (4)
 
     This average value B 1 ave is returned to the equation (2)
 
 B 1ave= Ub ·sin α1,
 
     so in accordance with
 
α1=sin −1 ( B 1ave/ Ub )  (5)
 
the first outer circumference bevel surface angle data α 1  at a certain angular position θ is calculated.
 
     Further, from the equation (1), the first outer circumference bevel surface diametrical direction component length data A 1  at a certain angular position θ is calculated in accordance with:
 
 A 1= Ub ·cos α1
 
     Note that, the second bevel surface axial direction component length B 2 ave, second outer circumference bevel surface angle data α 2 , and second outer circumference bevel surface diametrical direction component length data A 2  may also be similarly calculated. 
     For example, when using the first outer circumference bevel surface angle data α 1  and second outer circumference bevel surface angle data α 2  as the edge shape information, as the inspection results, a graph where the first outer circumference bevel surface angle data α 1 (θ) is plotted to correspond to each angular position θ is displayed like the broken line Q 14  (solid line) or broken line Q 24  (dotted line) of  FIG. 17 , and a graph where the second outer circumference bevel surface angle data α 2 (θ) is plotted to correspond to each angular position θ is displayed like the broken line Q 15  (solid line) or the broken line Q 25  (dotted line) of  FIG. 18 . In this case, for example, from the broken line Q 15  of  FIG. 18 , it is learned that the second outer circumference bevel surface angle data α 2  is comparatively larger in the angular position range 90° to 180°. From this, the semiconductor wafer  100  being inspected can be evaluated as one which changes in shape relatively largely at a slant angle of the second outer circumference bevel surface  101   c  of the angular position range 90° to 180° compared with other angular position ranges. 
     Furthermore, for example, when the graph of the first outer circumference bevel surface angle data α 1 (θ) (similar for second outer circumference bevel surface data α 2 (θ) as well) plotted to correspond to each angular position θ becomes the broken line Q 26  (solid line) of  FIG. 19 , the first outer circumference bevel surface angle α 1  becomes approximately constant over the entire circumference of the angular position of 0 degree to 360 degrees, but when the same graph becomes the broken line Q 16  (dotted line) of  FIG. 19 , the first outer circumference bevel surface angle α 1  greatly falls in the range of the angular position of 90 degrees to 270 degrees. If the outer circumference edge part  101  of the semiconductor wafer  100  has fluctuating parts of the first outer circumference bevel surface angle α 1  like shown by the broken line Q 16 , in the resist film coating process, it will become difficult to uniformly coat a resist film over the entire circumference of the outer circumference edge part  101  of the semiconductor wafer  100 . Further, if the coated resist film becomes uneven in thickness, eventually that resist film is liable to partially peel off and cause dust or to crack. Therefore, operationally, for example, when the first outer circumference bevel surface angle data α 1  becomes a characteristic like the broken line Q 16 , by adjusting the processing conditions in the previous processing step forming the outer circumference edge part  101  to characteristics so that the first outer circumference bevel surface angle data α 1  becomes like the broken line Q 26 , it becomes possible to reduce the obstructing factors in the post treatment process (film-forming process). 
     Note that, in the process of production of a semiconductor wafer  100 , it is possible to perform an operation similar to the operation based on the above-mentioned α 1  and α 2  based on the other edge shape information (outer circumference surface length data Ap(θ), first outer circumference bevel surface length data Ub(θ), and second outer circumference bevel surface length data Lb(θ): see  FIG. 11  to  FIG. 13 ). 
     Next, still another example of the output processing (S 17 ) will be explained. 
     As explained above, in  FIG. 16 , the following relationships stand.
 
 B 1= Ub ·sin α1  (6)
 
α1=sin −1 ( B 1/ Ub )  (7)
 
 B 2= Lb ·sin α2  (8)
 
α2=sin −1 ( B 2/ Lb )  (9)
 
 A 1= Ub ·cos α1  (10)
 
α1=cos −1 ( A 1/ Ub )  (11)
 
 A 2= Lb ·cos α2  (12)
 
α2=cos −1 ( A 2/ Lb )  (13)
 
 T=Ap+B 1+ B 2(T is thickness of semiconductor wafer  100 )  (14)
 
     From the above relationships, in accordance with the technique of recursive regression, the values of the parameters α 1  (first outer circumference bevel surface angle data), α 2  (second outer circumference bevel surface angle data), A 1  (first outer circumference bevel surface diametrical direction component length data), A 2  (second outer circumference bevel surface diametrical direction component length data), B 1  (first outer circumference bevel surface axial direction component length data), and B 2  (second outer circumference bevel surface axial direction component length data) can be found. 
     Specifically, first, if hypothesizing that at each angular position θ, B 1 =B 2 , from the equation (14), the following relationship stands:
 
 B 1= B 2=( T−Ap )/2  (15)
 
Further, by entering the prescribed value of the thickness T of the semiconductor wafer  100  (for example, 755 μm) and the value of the Ap (outer circumference end face length data) at each angular position θ obtained as explained above into equation (15), the values of B 1  and B 2  (=B 1 ) at each angular position θ are found as initial approximation values. Note that, the initial approximation values of B 1  and B 2  based on the above hypothesis, for example, as shown in  FIG. 20 , change in accordance with the change of the value of Ap (outer circumference end face length data) for each angular position θ.
 
     The initial approximation value of B 1  at each angular position θ and the Ub (first outer circumference bevel surface length data) at the corresponding angular position θ obtained as explained above are entered into equation (7) whereby the value of α 1  at each angular position θ is obtained, while the initial approximation value of B 2  (=B 1 ) at each angular position θ and the Lb (second outer circumference bevel surface length data) at the corresponding angular position θ obtained as explained above are entered into equation (9) whereby the value of α 2  at each angular position θ is found. Further, the value of α 1  at each angular position θ and the Ub (first outer circumference bevel surface length data) at the corresponding angular position θ obtained as explained above are entered into equation (10) whereby the value of A 1  at each angular position θ is found, while the value of α 2  at each angular position θ and the Lb (second outer circumference bevel surface length data) at the corresponding angular position θ obtained as explained above are entered into equation (12) whereby the value of A 2  at each angular position θ is found. 
     The approximation value of each of α 1 , α 2 , A 1 , and A 2  at each angular position θ when hypothesizing that the values of B 1  and B 2  (=B 2 ) at each angular position θ are the initial approximation values in this way is found as the first approximation value. After this, the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of the first approximation value of each of α 1 , α 2 , A 1 , and A 2  at the total angular position range (0° to 360°) of the semiconductor wafer  100  being inspected are found. Note that, the first approximation value of each of A 1  and A 2  for each angular position θ calculated under the above hypothesis, for example, becomes as shown in  FIG. 21A , while the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of A 1  and A 2  at the total angular position range (0° to 360°), for example, become as shown in  FIG. 21B . Further, the first approximation value of each of α 1  and α 2  for each angular position θ calculated under the above hypothesis, for example, becomes as shown in  FIG. 22A , while the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of α 1  and α 2  at the total angular position range (0° to 360°), for example, become as shown in  FIG. 22B . 
     Next, it is hypothesized that the value of α 1  at each angular position θ is the average value α 1 ave (fixed value) of the first approximation value and this average value α 1 ave and the Ub (first outer circumference bevel surface length data) at each angular position θ are entered into equation (6) whereby the value of B 1  at each angular position θ is found, while it is hypothesized that the value of α 2  at each angular position θ is the average value α 2 ave of the first approximation value and this average value α 2 ave and the Lb (second outer circumference bevel surface length data) at each angular position θ are entered into equation (8) whereby the value of B 2  at each angular position θ is found. Further, the average value α 1 ave and the Ub (first outer circumference bevel surface length data) at each angular position θ are entered into equation (10) whereby the value of A 1  at each angular position θ is found, while the average value α 2 ave of α 2  and the Lb (second outer circumference bevel surface length data) of each angular position θ are entered into equation (12) whereby the value of A 2  at each angular position θ is found. 
     The value of each of B 1  and B 2  at each angular position θ when hypothesizing that α 1 =α 1 ave and α 2 =α 2 ave at each angular position θ is found as a first approximation value, while the value of each of A 1  and A 2  at each angular position θ is found as a second approximation value. After this, the maximum values (MAX), minimum values (MIN), average values (AVE), and standard deviation values (STD) of the first approximation value of each of B 1  and B 2  and the second approximation value of each of A 1  and A 2  of the semiconductor wafer  100  being inspected at the total angular position (0° to 360°) are found. Note that, under the above hypothesis, the average values α 1 ave and α 2 ave of the first approximation values of α 1  and α 2  at each angular position θ are, for example, as shown in  FIG. 23 , constant, the first approximation value of each of B 1  and B 2  for each angular position θ calculated under that hypothesis, for example, becomes as shown in  FIG. 24A , and the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of B 1  and B 2  at the total angular position range (0° to 360°), for example, become as shown in  FIG. 24B . Further, the second approximation value of each of A 1  and A 2  for each angular position θ calculated under the above hypothesis, for example, becomes as shown in  FIG. 25A , while the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of A 1  and A 2  at the total angular position range (0° to 360°), for example, become as shown in  FIG. 25B . 
     Next, it is hypothesized that the value of A 1  at each angular position θ is the average value A 1 ave (fixed value) of the second approximation value and this average value A 1 ave and the Ub (first outer circumference bevel surface length data) at each angular position θ are entered into equation (11) whereby the value of α 1  at each angular position θ is found, while it is hypothesized that the value of A 2  at each angular position θ is the average value A 2 ave (fixed value) of the second approximation value and this average value A 2 ave and the Lb (second outer circumference bevel surface length data) at each angular position θ are entered into equation (13) whereby the value of α 2  at each angular position θ is found. Further, the value of α 1  at each angular position θ and the Ub (first outer circumference bevel surface length data) at the corresponding angular position θ are entered into equation (6) whereby the value of B 1  at each angular position θ is found, while the value of α 2  at each angular position θ and the Lb (second outer circumference bevel surface length data) at the corresponding angular position θ are entered into equation (8) whereby the value of B 2  at each angular position θ is found. 
     In this way, the value of each of α 1  and α 2  at each angular position θ is found as the second approximation value and the value of each of B 1  and B 2  at each angular position θ is found as the second approximation value when hypothesizing that A 1 =A 1 ave and A 2 =A 2 ave at each angular position θ. After this, the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation value (STD) of the second approximation value of each of B 1  and B 2  and the second approximation value of each of α 1  and α 2  at the total angular position (0° to 360°) of the semiconductor wafer  100  being inspected are found. Note that, under the above hypothesis, the average values A 1 ave and A 2 ave of the second approximation values of A 1  and A 2  at each angular position θ are, for example, as shown in  FIG. 26 , constant, the second approximation value of each of B 1  and B 2  for each angular position θ calculated under that hypothesis, for example, becomes as shown in  FIG. 27A , and the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of BE and B 2  at the total angular position (0° to 360°), for example, become as shown in  FIG. 27B . Further, the second approximation value of each of α 1  and α 2  for each angular position θ calculated under the above hypothesis, for example, becomes as shown in  FIG. 28A , while the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of each of α 1  and α 2  at the total angular position range (0° to 360°), for example, become as shown in  FIG. 28B . 
     After this, any of the set of the parameters B 1  and B 2 , the set of the parameters A 1  and A 2 , and the set of the parameters α 1  and α 2  is cyclically selected, the values at each angular position θ of the selected set of parameters is hypothesized as being the average values of the previously found approximation values, and the parameters of the other sets are computed based on this. This is successively repeated in the same way as explained above whereby the n-th approximation values at each angular position θ of each of the parameters B 1 , B 2 , A 1 , A 2 , α 1 , and α 2  (technique of recursive regression) are found. Further, the n-th approximation values of the parameters B 1 , B 2 , and A 1  obtained by repeating the above operations a predetermined number of times are output as the edge shape information. 
     The values (approximation values) of the edge shape information corresponding to each angular position θ may, for example, as shown in  FIG. 21A ,  FIG. 22A ,  FIG. 24A ,  FIG. 25A ,  FIG. 27A , and  FIG. 28A , be graphed for display (output) as the inspection results. Further, the statistical values of the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) in the total angular range (0° to 360°) found from the values of the edge shape information at each angular position θ may, as shown in  FIG. 21B ,  FIG. 22B ,  FIG. 24B ,  FIG. 25B ,  FIG. 27B , and  FIG. 28B , be tabularized for display (output) as the inspection results. Note that the output format of the inspection results is not limited to the graph format and the table format and may be other formats as well. 
     When graphing the values (approximation values) of the edge shape information corresponding to the different angular positions θ of the semiconductor wafer  100  being inspected for display (output) as the inspection results, it becomes possible to visually judge the shape of the outer circumference edge part of the semiconductor wafer  100  based on the shape of the graph. Further, when tabularizing the statistical values of the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) at the total angular range (0° to 360°) found from the values of the edge shape information of the semiconductor wafer  100  being inspected for display (output) as the inspection results, it is possible to easily manage the trends in the shape of the outer circumference edge part of a semiconductor wafer  100  based on the trends in these statistical values in the process of production of a semiconductor wafer  100 . 
     In the above example, the statistical values (the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) at the total angular range (0° to 360°)) of each of the parameters B 1 , B 2 , A 1 , A 2 , α 1 , and α 2  were obtained for each of the semiconductor wafers  100 , but the statistical values may also be obtained for each cassette in which a plurality of semiconductor wafers  100  are stored, for each lot of semiconductor wafers  100 , or for each other unit. Further, the statistical values need not be all of the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) and may be one or more of the same. 
     Note that, the value of each of the first outer circumference bevel surface axial direction component length data B 1  and second outer circumference bevel surface axial direction component length B 2  at each angular position θ obtained based on the above-mentioned technique of recursive regression and the values of the outer circumference end face length data Ap at the corresponding angular position θ obtained by measurement may be entered into the above-mentioned equation (14) to find the thickness T of the semiconductor wafer  100  at each angular position θ. The thickness T of the semiconductor wafer  100  at each angular range θ is found, for example, as shown in  FIG. 29A , while further, the maximum value (MAX), minimum value (MIN), average value (AVE), and standard deviation (STD) of T are found, for example, as shown in  FIG. 29B . 
     INDUSTRIAL APPLICABILITY 
     The edge inspection apparatus and edge inspection method of a semiconductor wafer according to the present invention has the advantageous effects of enabling easy inspection of the shape of outer circumference edge part of a semiconductor wafer by the same process or same apparatus as inspection for the presence of cracks, particles, or other defects at the outer circumference edge part and is useful as an edge inspection apparatus and edge inspection method of a semiconductor wafer for inspecting the outer circumference edge part of a semiconductor wafer.