PATENT ABSTRACT
The present invention suppresses reductions in inspection precision caused by reflected and scattered light produced by wafer holders. In a wafer holder ( 10 ) that has protruding support parts ( 11 ) that contact and support a wafer and groove parts ( 12 ) that are separated from the wafer, the protruding support parts ( 11 ) are extended continuously from a part that supports one edge of the wafer to a part that supports the other edge of the wafer. Connecting parts ( 13 ) that connect adjacent protruding support parts ( 11 ) are provided in each of the vicinity of the parts supporting the one edge and the vicinity of the parts supporting the other edge.

PATENT DESCRIPTION
TECHNICAL FIELD 
       [0001]    The present invention relates to a substrate observation apparatus and inspection apparatus, a substrate support member, and a method for manufacturing semiconductor devices. 
       BACKGROUND ART 
       [0002]    While miniaturization of semiconductors is said to be approaching its limit, mounting semiconductor chips three-dimensionally has such merits as improving performance, saving electric power, saving space, etc., and thus is spreading rapidly, along with miniaturization of semiconductors, as a means for improving additional value. Three-dimensional mounting is a technique of thinning a plurality of semiconductor chips to the extent of 10 to 50 μm, and then stacking the same. Each of the stacked chips finally becomes as thin as 10 to 50 μm, while a number of electrodes or vias which penetrate through the chips are used to electrically connect the vertical layered chips (TSV: Through-Silicon Via). In this manner, it is possible to electrically connect the chips at a shorter distance than the conventional SiP (System in a Package) in which chips are horizontally aligned and connected. Therefore, compared with the conventional SiP (System in a Package) in which chips are horizontally aligned and connected, it is more efficient in achievement of improving the operation speed of elements, saving electric power, and saving space. 
         [0003]    There are a variety of methods for forming the TSV (Through-Silicon Via) such as in the cases of carrying out the formation before forming elements on the semiconductor chips, carrying out the formation after forming elements on the semiconductor chips, etc. In any of these cases, however, each TSV is formed by forming a deep hole tiny in diameter on a wafer (silicon substrate), and then filling the hole with a highly conductive substance such as copper or the like after covering the lateral wall of the hole with an insulation film. On this occasion, inspections are important in the process of forming the TSVs and after the TSVs are formed, and these inspections are carried out by breaking the wafer, and observing the same with an SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope) or the like. With this method, whereas it is possible to observe an actual shape of the cross section, the inspection is destructive, and takes time. 
         [0004]    On the other hand, although there are also methods for observing the surface of a wafer with a microscope or the like, it is merely possible to confirm the condition of the wafer surface with such methods. Further, although transmission images are also observed with microscopes using infrared light, because only a very small area is observable at one time, it is not practical to inspect the TSVs in the whole wafer surface with such a method. 
         [0005]    However, there are techniques of inspecting a repetitive pattern formed on a semiconductor wafer according to variation in diffracted light, polarization state, etc. (see Patent Literature 1, for example). According to such a method, it is possible to inspect a wide area in a short time, as well as to detect, in a short time with a good sensitivity, any abnormity due to focus variation or dose (exposure energy) variation of an exposure device for forming the pattern, and any abnormity arising from some defect or maladjustment of a processing device. Further, as a substrate support member of an inspection apparatus using this method, a wafer holder  500  is known to be configured, as shown in  FIGS. 18(   a ) and  18 ( b ) for example, to suck and hold a wafer W by letting a vacuum pump or the like apply a negative pressure to a plurality of suction grooves  512  formed to align concentrically in the support surface for the wafer W. Further, as another example of the substrate support member, such configuration is also known as to suck and hold a wafer by supporting the same with a plurality of small cylindrical support portions. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PATENT LITERATURE 1: U.S. Pat. No. 7,298,471 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    However, with conventional inspection apparatus using the method of inspecting a repetitive pattern formed on the semiconductor wafer according to the variation in diffracted light, polarization state, etc., because the wavelength of illumination light is in the wavelength range of visible light to deep ultraviolet light, it is only possible to inspect the abnormity in the diameter and opening parts of TSVs in the wafer surface, i.e., the condition in the vicinity of the wafer surface, but it is not possible to inspect the abnormity in deep parts of the TSV holes. To address this problem, such devices are being developed as to obtain the diffracted light from the TSV structure inside a wafer by setting the wavelength of the illumination light to be in the wavelength range of infrared, and using the fact that infrared light has a high transmittance to silicon which is the material of the wafer. 
         [0008]    When acquiring an image based on the diffracted light from the wafer as an inspection image of the wafer by using infrared light to irradiate the wafer supported by the conventional substrate support member as described earlier, then part of the irradiated infrared light is transmitted to the opposite side of the wafer. Therefore, other than the diffracted light from the wafer to be inspected, reflected and scattered light from the edges and the like of the support portions (the suction grooves  512 ) of the substrate support member may reach the camera of a light receiving system, and become noise in the inspection image as shown in  FIG. 18(   a ), and thereby the inspection precision is liable to reduction. 
         [0009]    The present invention is made in view of such problems, and an object thereof is to suppress the reduction in inspection precision due to the reflected and scattered light arising from the substrate support member. 
       Solution to the Problem 
       [0010]    In order to achieve such object as above, an aspect of the present invention provides an observation device including: a substrate support member supporting a substrate; an illumination section irradiating the substrate supported by the substrate support member with illumination light having transmittance with respect to the substrate; and a light detection section detecting light from the substrate irradiated with the illumination light, wherein the substrate support member has a protruding support portion which contacts with the substrate when supporting the substrate, and a separate portion which is located apart from the substrate; and wherein in a part of the substrate support member supporting an observation area to be observed on the substrate, the support portion and the separate portion of the substrate support member do not have any line or plane orthogonal to an incidence plane of the illumination light to the substrate. 
         [0011]    Further, in the observation device described above, it is possible to use infrared of a wavelength equal to or longer than 700 nm as the illumination light. 
         [0012]    Further, the observation device described above may further include a transport device transporting the substrate to the substrate support member, wherein the transport device has a holding member which holds an edge portion of the substrate when transporting the substrate; the substrate support member has a relief portion formed not to contact with the holding member when the transport device transports the substrate to the substrate support member; and the substrate support member is arranged not to have any line or plane orthogonal to the incidence plane of the illumination light in a part of the relief portion supporting the observation area. 
         [0013]    Further, in the observation device described above, the substrate support member may be configured to suck and hold the substrate by sucking air from a space formed by the supported substrate and the support portion so as to cause pressure reduction in the space; and a suction portion may be provided to suck the air in a part of the substrate support member supporting the other area than the observation area. 
         [0014]    Further, in the observation device described above, between the support portion and another support portion adjacent to the former support portion, a pressure reduction auxiliary portion may be provided to prevent inflow of air or gas from outside into the space formed by the supported substrate and the support portions. 
         [0015]    Further, in the observation device described above, the support portion may extend along the incidence plane of the illumination light. 
         [0016]    Further, in the observation device described above, the support portion may have a linear portion extending from one end to the other end of the observation area along the incidence plane of the illumination light. 
         [0017]    Further, the observation device described above may further include a rotary section which rotates the substrate support member about an axis vertical to the incidence plane of illumination light. Further, in the observation device described above, on a surface of the substrate support member facing the substrate, a layer of an infrared absorber may be formed to absorb infrared; the light detection section may have a cooled image sensor; and the illumination section may have a telecentric optical system which causes the illumination light to become parallel light to illuminate the substrate. 
         [0018]    Further, another aspect of the present invention provides an inspection device including: the observation device described above; and an inspection section which inspects whether or not there is an abnormity in the substrate based on a detection signal of the light detected by the light detection section of the observation device. 
         [0019]    Further, still another aspect of the present invention provides a method for manufacturing a semiconductor device, the method including: an exposing step of exposing a predetermined pattern onto a surface of a substrate; an etching step of etching the surface of the substrate according to the exposed pattern; and an inspecting step of inspecting the substrate with the pattern formed in the surface through the exposing or the etching, wherein the inspection device according to the present invention is used to carry out the inspecting step. 
         [0020]    Further, still another aspect of the present invention provides a substrate support member including: protruding support portions which support a substrate by contacting with the substrate; and a separate portion which is located apart from the substrate, wherein the protruding support portions extend continuously from a part supporting one end of the substrate to a part supporting the other end, and have connection portions which connect adjacent ones of the protruding support portions, respectively in the vicinity of the part supporting the one end and in the vicinity of the part supporting the other end. 
         [0021]    Further, in the substrate support member described above, the protruding support portions may each be formed into an approximate cuboid. 
         [0022]    Further, in the substrate support member described above, in the vicinity of each of the connection portions and in the ambit enclosed by the adjacent ones of the protruding support portions and the connection portions, a suction portion may be provided to be capable of sucking air from a space formed by the supported substrate and the support portions. 
         [0023]    Further, still another aspect of the present invention provides an observation device including: a substrate support member supporting a substrate; an illumination section irradiating the substrate supported by the substrate support member with illumination light having transmittance with respect to the substrate; and a light detection section detecting light from the substrate irradiated with the illumination light, wherein the substrate support member has a protruding support portion which contacts with the substrate when supporting the substrate, and a separate portion which is located apart from the substrate; and wherein in a part of the substrate support member supporting an observation area to be observed on the substrate, the support portion and the separate portion of the substrate support member intersect an incidence plane of the illumination light to the substrate at an acute angle or obtuse angle. 
       Advantageous Effects of Invention 
       [0024]    According to the present invention, it is possible to suppress the reduction in inspection precision due to the reflected and scattered light arising from the substrate support member. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0025]      FIG. 1(   a ) is a plan view of a wafer holder according to a first embodiment; 
           [0026]      FIG. 1(   b ) is a sectional view along the line indicated by the arrows b-b in  FIG. 1(   a ); 
           [0027]      FIG. 2  is a schematic configuration diagram of a wafer inspection apparatus; 
           [0028]      FIG. 3  is a plan view showing a transport unit of the inspection apparatus; 
           [0029]      FIG. 4(   a ) is a plan view of a wafer holding device; 
           [0030]      FIG. 4(   b ) is a sectional view along the line indicated by the arrows b-b in  FIG. 4(   a ); 
           [0031]      FIG. 5  is a flowchart showing a wafer inspection method; 
           [0032]      FIG. 6(   a ) is an enlarged view of a wafer when observed from above; 
           [0033]      FIG. 6(   b ) is an enlarged sectional view of the wafer; 
           [0034]      FIG. 7(   a ) is an enlarged sectional view of a wafer with the holes swelling out in the middle parts; 
           [0035]      FIG. 7(   b ) is an enlarged sectional view of a wafer with the holes tapering off in the deep parts; 
           [0036]      FIG. 8  is a plan view showing a first modification of the wafer holder according to the first embodiment; 
           [0037]      FIG. 9  is a plan view showing a second modification of the wafer holder according to the first embodiment; 
           [0038]      FIG. 10  is a sectional side view showing a third modification of the wafer holder according to the first embodiment; 
           [0039]      FIG. 11(   a ) is a plan view of a wafer holder according to a second embodiment; 
           [0040]      FIG. 11(   b ) is a sectional view along the line indicated by the arrows b-b in  FIG. 11(   a ); 
           [0041]      FIG. 12  is a plan view showing a modification of the wafer holder according to the second embodiment; 
           [0042]      FIG. 13(   a ) is a plan view of a wafer holder according to a third embodiment; 
           [0043]      FIG. 13(   b ) is a sectional view along the line indicated by the arrows b-b in  FIG. 13(   a ); 
           [0044]      FIG. 14  is a plan view of a wafer holder according to a fourth embodiment; 
           [0045]      FIG. 15  is a sectional side view of the wafer holder according to the fourth embodiment; 
           [0046]      FIG. 16  is a sectional side view showing a modification of support portions; 
           [0047]      FIG. 17  is a flowchart showing a method for manufacturing a semiconductor device; 
           [0048]      FIG. 18(   a ) is a plan view showing an example of a conventional wafer holder; and 
           [0049]      FIG. 18(   b ) is a sectional side view showing the example of the conventional wafer holder. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0050]    Hereinbelow, referring to the accompanying drawings, explanations will be given about a few embodiments of the present invention.  FIG. 2  shows an inspection apparatus of a first embodiment, and this apparatus inspects, at one time, the entire surface of a wafer W which is a silicon substrate (the whole of an aftermentioned observation area T 1 ). The inspection apparatus  1  of the first embodiment includes a wafer holder  10  supporting the approximately circular-disk-like wafer W, and the wafer W transported there by a transport system  50  shown in  FIG. 3  is placed on the wafer holder  10  and held fixedly through vacuum suction. By using a tilt mechanism  9  provided on the wafer holder  10 , it is possible to tilt the wafer W held on the wafer holder  10  around an axis passing through the surface of the wafer W. That is, it is possible to rotate the wafer W held on the wafer holder  10  around the axis passing through the surface of the wafer W, i.e., around an axis vertical to an incidence plane of illumination light. By virtue of this, the incidence angle of the illumination light becomes adjustable. 
         [0051]    The inspection apparatus  1  is configured to further include an illumination system  20  which irradiates the surface of the wafer W held on wafer holder  10  with the illumination light as parallel light, a light receiving system  30  which condenses or focuses the light from the wafer W when receiving the irradiation of the illumination light, an imaging section  35  which takes an image of the wafer W by receiving the light condensed by the light receiving system  30 , a control section  40  which carries out operation control for the device, an image processing section  41  which carries out image processing and the like, and a display section  42  which carries out image display. The illumination system  20  is configured to have an illumination unit  21  which emits the illumination light, and an illumination-side concave mirror  25  which reflects the illumination light emitted from the illumination unit  21  toward the surface of the wafer W. The illumination unit  21  is configured to have a light source  22  such as a metal halide lamp, mercury lamp or the like, a dimmer  23  which extracts the light having a predetermined wavelength among the light from the light source  22  and which adjusts the intensity of the extracted light, and a light guiding fiber  24  which guides the light from the dimmer  23  as the illumination light to the illumination-side concave mirror  25 . 
         [0052]    Then, the light from the light source  22  passes through the dimmer  23 , and the illumination light having the predetermined wavelength with a predetermined intensity emits from the light guiding fiber  24  toward the illumination-side concave mirror  25  to become divergent light. Because the emitting portion of the light guiding fiber  24  is arranged on the focal plane of the illumination-side concave mirror  25 , the illumination light emitted from the light guiding fiber  24  to the illumination-side concave mirror  25  is then caused by the illumination-side concave mirror  25  to become parallel (telecentric) light which irradiates the entire surface of the wafer W held by the wafer holder  10 . Further, with respect to the wafer W, the incoming or incidence and outgoing angles of the illumination light are adjustable by tilting (inclining) the wafer holder  10  to change the angle of placing the wafer W. 
         [0053]    The light receiving system  30  condenses the outgoing light from the wafer W (the diffracted light, the regular reflection light and the like). The light receiving system  30  is composed primarily of a light-receiving-side concave mirror  31  arranged to face the wafer holder  10 . The outgoing light condensed by the light-receiving-side concave mirror  31  comes onto the imaging plane of the imaging section  35  to form an image of the wafer W. The imaging section  35  includes unshown objective lens, image sensor and the like to generate an image signal (detection signal) by photoelectrically converting the image of the wafer W formed on the imaging plane of the image sensor, and outputting the generated image signal to the image processing section  41  via the control section  40 . 
         [0054]    The control section  40  controls the operations of the wafer holder  10  and tilt mechanism  9 , the illumination unit  21 , the imaging section  35 , the transport system  50  (see  FIG. 3 ), and the like, respectively. The image processing section  41  generates an image (digital image) of the wafer W based on the image signal inputted from the imaging section  35 . A database (not shown) electrically connected with the image processing section  41  prestores the image data of a nondefective wafer. On generating the image of the wafer W, the image processing section  41  compares the generated image data of the wafer W with the image data of the nondefective wafer stored in the database to inspect whether or not there is any abnormity (defection) in the wafer W. Then, the inspection result from the image processing section  41  and the image of that wafer W are outputted and displayed on the display section  42 . 
         [0055]    However, while being contained in a wafer carrier C as shown in  FIG. 3 , the inspection object wafer W is transported from a processing device (an etching device, for example) to an unshown port portion of the inspection apparatus  1  after an inspection object process (an etching process, for example), and then taken out of the wafer carrier C to be further transported onto the wafer holder  10  by the transport system  50  provided in the inspection apparatus  1 . As shown in  FIG. 3 , the transport system  50  includes a first transport device  51 , a second transport device  61 , and a third transport device  71 . 
         [0056]    The first transport device  51  is configured to include a robot arm  52  which is capable of chucking (sucking and holding, for example) the back side of the wafer W. The first transport device  51  takes out the wafer W contained in the wafer carrier C to transport the wafer W to the second transport device  61  and, on the other hand, takes in the inspected wafer W transported there by the third transport device  71  to let the wafer carrier C contain the same. The second transport device  61  is configured to include a transport stage  62  which is capable of rotation and parallel movement with the back side of the wafer W being chucked (sucked and held, for example), and an alignment portion  63  which carries out alignment with reference to the pattern or outer edge portion of the wafer W (a notch, an orientation flat or the like). After taking in the wafer W transported there by the first transport device  51  and carrying out the alignment, the second transport device  61  transports the wafer W to the third transport device  71 . The second transport device  61  carries out the alignment which is one of the transport functions. 
         [0057]    The third transport device  71  is configured to include a transport arm  72  which is capable of swinging within an approximately horizontal plane, and a wafer holding device  73  which is slidably fitted on the transport arm  72  to hold edge portions of the wafer W. The third transport device  71  takes in the wafer W aligned by the second transport device  61  to transport the wafer W onto the wafer holder  10  and, on the other hand, transports the inspected wafer W on the wafer holder  10  to the first transport device  51 . (The inspected wafer W is transferred from the third transport device  71  to the first transport device  51 . The first transport device  51  takes in the wafer W to let the wafer carrier C contain the wafer W.) As shown in  FIGS. 4(   a ) and  4 ( b ), the wafer holding device  73  is configured to have a plate-like first base member  74  slidably fitted below the transport arm  72 , a second base member  75  vertical-movably fitted below the first base member  74 , a raising and lowering mechanism  76  which vertically moves (raises and lowers) the second base member  75  relative to the first base member  74 , four holding members  77  which are rotatably fitted on the second base member  75  to hold edge portions of the wafer W, and four motors for opening/closing operation  78  which respectively drive the holding members  77  to rotate. 
         [0058]    Detailed illustration being omitted, the raising and lowering mechanism  76  includes two guide shafts which extend vertically across the first base member  74  and second base member  75 , a rack gear fitted on the second base member  75 , and a pinion gear fitted on the first base member  74  to engage the rack gear. Further, the raising and lowering mechanism  76  is not limited to the configuration using a combination of the rack gear and pinion gear, but may adopt various other configurations as necessary. For example, it may either be configured to use a linear actuator such as an air cylinder, electromagnetic solenoid or the like, or be configured to use a ball screw and motor. Further, those configurations are merely exemplifications; hence, the present invention should not be limited thereto. 
         [0059]    As shown in the enlarged view of  FIG. 4(   b ), the holding members  77  are each formed into a cylinder in which an engagement groove  77   a  is formed in its barrel to be engageable with an edge portion of the wafer W. Further, in a lateral portion of each of the holding members  77 , a planate cutaway  77   b  is formed to cut away part of the engagement groove  77   a . The four holding members  77  are coupled respectively to the rotary shafts of the four motors for opening/closing operation  78  fitted on the second base member  75 , whereby the holding members  77  become rotatable respectively around the rotary shafts of the motors for opening/closing operation  78 , as well as capable of vertical movement (up-down movement) relative to the first base member  74 . Further, the four holding members  77  are arranged at such intervals as to locate in the vicinity of two edge portions of the wafer W such that, as shown on the right side of the enlarged view of  FIG. 4(   a ), when not holding edge portions of the wafer W, the holding members  77  are each rotationally displaced to a non-holding position to let the cutaways  77   b  face edge portions of the wafer W. On the other hand, as shown on the left side of the enlarged view of  FIG. 4(   a ), when holding edge portions of the wafer W, the four holding members  77  are each rotationally displaced to a holding position to let the engagement grooves  77   a  engage the edge portions of the wafer W. In this manner, by rotating the holding members  77 , it is possible to either hold edge portions of the wafer W or release the holding of edge portions of the wafer W. 
         [0060]    As shown in  FIGS. 6(   a ) and  6 ( b ) for example, a repetitive pattern (hole pattern) is formed in the surface of the wafer W. This pattern A has a structure of forming holes (or vias) regularly arranged in a bare wafer made of silicon (Si). Here,  FIG. 6(   a ) is an enlarged view of part of the wafer W when observed from above, while  FIG. 6(   b ) is an enlarged sectional view of the wafer W. As an example, the hole diameter is 2 μm, the hole pitch or interval is 4 μm, and the hole depth is 20 μm. Further, the wafer W is 725 μm thick, but  FIGS. 6(   a ) and  6 ( b ) illustrate the wafer W without describing its thickness. Further,  FIGS. 6(   a ) and  6 ( b ) show the silicon portion with oblique (hatched) lines and the holes in blank. Further, the abovementioned dimensions, such as the thickness of the wafer W, the pitch, depth and diameter of the holes, etc., are merely exemplifications; hence, the present invention should not be limited thereto. 
         [0061]      FIGS. 7(   a ) and  7 ( b ) show examples of abnormally formed holes constituting the pattern A. Here,  FIG. 7(   a ) shows the holes swelling out in the middle parts, while  FIG. 7(   b ) shows the holes tapering off in the deep parts. Since such kinds of shapes will give rise to problems in the succeeding formation process and the function of completed TSVs, it is necessary to find out those holes through inspection. In the first embodiment, the area of the wafer W to be inspected and observed is referred to as the observation area. The observation area T 1  of the first embodiment is, as shown in  FIG. 1(   a ), an area inside of the part of the wafer W where an EBR (Edge Bead Removal) process is carried out. Further, the EBR process is a process of removing the residues of resist brought about on some edge portion of the wafer W by peeled-off resist and the like. 
         [0062]    Further, the observation area is not limited to the abovementioned area, but can also be an area of the wafer W inside of the inclined part (bevel) of the edge portion of the wafer W. Further, the observation area can also be an area of the wafer W where the pattern A is formed. Further, when there is no observation object in a street or path, then it is also possible to set an observation area to exclude that street from the observation area. 
         [0063]    Next, referring to  FIG. 1 , the wafer holder  10  according to the first embodiment will be explained. Using ceramic or the like, the wafer holder  10  of the first embodiment is formed into an approximately circular disk to fit the shape of the wafer W. The upper-end portion (front-end portion) of the wafer holder  10  is formed with a plurality of protruding support portions  11  to contact with the wafer W when supporting the wafer W, and a plurality of groove portions  12  which are formed between these plurality of support portions  11  and apart from the wafer W. 
         [0064]    Each of the support portions  11  is formed into an approximate cuboid to continuously support the wafer W from one end to the other end, and arranged to extend along an incidence plane of the illumination light to the wafer W. Further, the incidence plane of the illumination light is a plane determined by the incident light and incident normal of the illumination light (the normal of the surface of the wafer W or the normal of the surface of the support portions  11  supporting the wafer W). Further, the plurality of support portions  11  are formed to be approximately parallel to each other, as well as formed to let the plurality of groove portions  12  be approximately parallel to each other between the respective support portions  11 . Therefore, with each of the support portions  11 , there are formed a support surface  11   a  which is a flat surface to contact with the back side of the wafer W, lateral sides  11   b  approximately vertical to the support surface  11   a , an edge line  11   c  which is an intersectional line between the support surface  11   a  and the lateral sides  11   b , and the like, all of which extend along the incidence plane of the illumination light. 
         [0065]    As described above, the plurality of groove portions  12  are formed to be approximately parallel to each other between the respective support portions  11 . With the wafer W being supported by the wafer holder  10 , a pressure reduction space S 1  is formed with each of the groove portions  12  to be enclosed by the wafer W, and the support portions  11  positioned on both sides of the corresponding groove portion  12 . By sucking the air from the pressure reduction spaces S 1  formed respectively with the groove portions  12  to reduce the air pressures inside the pressure reduction spaces S 1 , the wafer W is sucked and held on the wafer holder  10 . Further, a plurality of connection portions  13  are each formed to connect the corresponding ends of one adjacent pair of the support portions  11  at a portion of the wafer holder  10  supporting one end or the other end of the wafer W and, by those connection portions  13 , both ends of each of the groove portions  12  are closed up to prevent inflow of air or gas into the above pressure reduction spaces S 1  from outside. 
         [0066]    Further, in the bottoms of the respective groove portions  12 , suction holes  14  are formed for sucking air from the respective pressure reduction spaces S 1 . The suction holes  14  are arranged respectively in the bottoms of the groove portions  12  and in the vicinity of the connection portions  13 , i.e., in the portion of the wafer holder  10  supporting the area other than the observation area T 1  (the area outside of the observation area T 1 ), and formed to extend downward from the bottoms of the groove portions  12 . The lower ends of the suction holes  14  are connected respectively to an internal passage  15  formed inside the wafer holder  10 , while the internal passage  15  is connected to an unshown vacuum source (a shared pressure reduction line on a production line, for example) via a vacuum piping  19  fitted below the wafer holder  10 . 
         [0067]    Further, a black coating capable of absorbing infrared rays is applied to the surface of the upper-end portion (front-end portion) of the wafer holder  10  where the support portions  11 , groove portions  12  and the like are formed. Further, without being limited to a black coating, a layer of any suitable infrared absorber may be formed on the upper-end surface of the wafer holder  10  as necessary. For example, as the infrared absorber, it is also possible to apply or attach carbon black, diimmonium salt, aminium salt, or the like, to the surface of the wafer holder  10 . Further, black SiC (silicon carbide) may also be used to form the wafer holder  10 . 
         [0068]    At the left and right sides of the wafer holder  10 , a pair of relief portions  16  (also see  FIG. 4(   a )) are formed to prevent the wafer W from contact with the holding members  77  of the wafer holding device  73  when the third transport device  71  transports the wafer W onto the wafer holder  10 . These two relief portions  16  are edges which form cutaways of the approximately circular-disk-like wafer holder  10 , and the wafer holder  10  is disposed such that the lateral sides and edge lines (of the wafer holder  10 ) forming the respective relief portions  16  may extend along the incidence plane of the illumination light. 
         [0069]    Referring to the flowchart shown in  FIG. 5 , an explanation will be given about a method for inspecting the wafer W by using the inspection apparatus  1  configured in the above manner. Further, the control section  40  issues commands based on a sequence stored in an unshown storage portion to carry out a series of operations explained below. First, the first transport device  51  chucks the back side of the wafer W contained in the wafer carrier C to take out the wafer W from the wafer carrier C (step S 101 ). Next, the first transport device  51  transports and transfers the wafer W taken out from the wafer carrier C to the second transport device  61  (step S 102 ). At this time, the first transport device  51  (robot arm  52 ) releases the chucking of the back side of the wafer W, while the second transport device  61  (transport stage  62 ) chucks the back side of the wafer W. 
         [0070]    Next, the second transport device  61  causes the transport stage  62  and alignment portion  63  to carry out the alignment of the wafer W (step S 103 ). At this time, it is configured to acquire positional information of the pattern A formed on the surface of the wafer W, and to carry out the alignment (to detect and store the wafer coordinates based on the notch, orientation flat, alignment mark, or the like) such that the wafer W can be placed on the wafer holder  10  at a predetermined position and in a predetermined direction. 
         [0071]    Next, the second transport device  61  transports the aligned wafer W to a predetermined first transfer position to transfer the same to the third transport device  71  (step S 104 ). At this time, at the first transfer position, the second transport device  61  (transport stage  62 ) releases the chucking of the back side of the wafer W, while the third transport device  71  (wafer holding device  73 ) holds edge portions of the wafer W (step S 105 ). Further, in order for the wafer holding device  73  to hold the edge portions of the wafer W, after the raising and lowering mechanism  76  and the like adapt the height of the engagement grooves  77   a  of the four holding members  77  to the height of the edge portions of the wafer W, each of the holding members  77  is rotationally displaced from the aforementioned non-holding position to the holding position. 
         [0072]    Next, the third transport device  71  transports the wafer W from the first transfer position onto the wafer holder  10  (step S 106 ). At this time, on the wafer holder  10  maintained in an approximately horizontal state by the tilt mechanism  9 , the third transport device  71  (wafer holding device  73 ) releases the holding of the edge portions of the wafer W, while the wafer holder  10  chucks the back side of the wafer W (step S 107 ). 
         [0073]    Further, in order for the wafer holding device  73  to release the holding of the edge portions of the wafer W, each of the holding members  77  is rotationally displaced from the aforementioned holding position to the non-holding position. On the other hand, in order for the wafer holder  10  to chuck the back side of the wafer W, with the back side of the wafer W being in contact with the wafer holder  10 , the vacuum source (not shown) is used to suck the air, via the suction holes  14 , from the pressure reduction spaces S 1  formed respectively with the groove portions  12  of the wafer holder  10 . By virtue of this, the pressures inside the pressure reduction spaces S 1  are reduced, and thus the wafer W is sucked and held on the wafer holder  10 . 
         [0074]    In this manner, when the wafer W to be inspected is transported with its surface facing upward onto the wafer holder  10 , then the third transport device  71  retreats from the wafer holder  10  to a predetermined retreat position so as not to obstruct the inspection (step S 108 ). After the third transport device  71  retreats from the wafer holder  10 , inspection of the wafer W is carried out (step S 109 ). 
         [0075]    When the inspection of the wafer W is finished, then the third transport device  71  moves from the predetermined retreat position to the wafer holder  10  (step S 110 ). At this time, on the wafer holder  10 , the wafer holder  10  releases the chucking of the back side of the wafer W, while the third transport device  71  (wafer holding device  73 ) holds edge portions of the wafer W (step S 111 ). 
         [0076]    Further, in order for the wafer holder  10  to release the chucking of the back side of the wafer W, after the tilt mechanism  9  restores the wafer holder  10  to an approximately horizontal state, a gas supply device (not shown), switching valve (not shown) and the like are used to supply air or a gas from the suction holes  14  to the aforementioned pressure reduction spaces S 1  formed in the wafer holder  10 . By virtue of this, the reduced pressures inside the pressure reduction spaces S 1  return to the atmospheric pressure, thereby releasing the wafer W from being sucked by the wafer holder  10 . On the other hand, in order for the wafer holding device  73  to hold edge portions of the wafer W, after the raising and lowering mechanism  76  and the like adapt the height of the engagement grooves  77   a  of the four holding members  77  to the height of the edge portions of the wafer W, each of the holding members  77  is rotationally displaced from the aforementioned non-holding position to the holding position. 
         [0077]    Next, the third transport device  71  transports the inspected wafer W from the wafer holder  10  to a predetermined second transfer position to transfer the same to the first transport device  51  (step S 112 ). At this time, at the second transfer position, the third transport device  71  (wafer holding device  73 ) releases the holding of the edge portions of the wafer W, while the first transport device  51  (robot arm  52 ) chucks the back side of the wafer W (step S 113 ). 
         [0078]    Then, the first transport device  51  transports the inspected wafer W from the first transfer position into the wafer carrier C to contain the wafer W (step S 114 ). At this time, the first transport device  51  (robot arm  52 ) releases the chucking of the back side of the wafer W in the wafer carrier C, and then retreats from the wafer carrier C. This finishes the inspection of the one wafer W which is an inspection object. Further, when the wafer carrier C contains a plurality of wafers W to be inspected, then until all of the wafers W are finished with the inspection, the aforementioned process from step S 101  to step S 114  is repeated. 
         [0079]    Next, the inspection of the wafer W in step S 109  will be explained. In order to inspect the wafer W, first, the surface of the wafer W sucked and held by the wafer holder  10  is irradiated with illumination light transmissive for the wafer W (light of the wavelengths from 900 nm to 1100 nm, for example). At this time, the illumination light having a predetermined wavelength (in the range of visible or near-infrared light) is emitted from the illumination unit  21  to the illumination-side concave mirror  25 , reflected from the illumination-side concave mirror  25  to become parallel light, and irradiates the entire surface of the wafer W held by the wafer holder  10 . 
         [0080]    Still at this time, by adjusting the wavelength of the illumination light emitted from the illumination unit  21 , and the rotation angle and tilt angle of the wafer W held on the wafer holder  10  (to be referred to hereinbelow as satisfying a diffraction condition), the imaging section  35  can receive the diffracted light from the repetitive pattern A regularly formed at a predetermined pitch to form an image of the wafer W. In particular, the transport stage  62  and alignment portion  63  of the second transport device  61  rotate the wafer W such that the illumination direction on the surface of the wafer W (the direction from the illumination system  20  toward the light receiving system  30 ) may consist with the repetitive direction of the pattern A, while the tilt mechanism  9  carries out such a setting as to satisfy the following Formula 1 based on Huygens&#39; principle (to tilt the wafer holder  10 ), where P represents the pitch of the pattern A, λ represents the wavelength of the illumination light irradiating the surface of the wafer W, θ 1  represents the incoming angle of the illumination light, and θ 2  represents the outgoing angle of the nth-order diffracted light. 
         [0000]        P=n ×λ/{sin(θ1)−sin(θ2)}  [Formula 1]
 
         [0081]    Next, it is configured to detect the diffracted light from the wafer W irradiated with the illumination light. The diffracted light arising from the repetitive pattern A of the wafer W is condensed by the light-receiving-side concave mirror  31 , and then comes onto the imaging plane of the imaging section  35  to form an image of the wafer W (an image formed from the diffracted light). At this time, the image sensor of the imaging section  35  generates an image signal by photoelectrically converting the image of the wafer W formed on the imaging plane, and outputs the generated image signal to the image processing section  41  via the control section  40 . 
         [0082]    Then, the wafer W is inspected by using information of the detected diffracted light (the diffracted light intensity, for example). At this time, the image processing section  41  generates an image of the wafer W (a digital image) based on the image signal inputted from the imaging section  35 . Further, having generated the image of the wafer W (the digital image), the image processing section  41  compares the generated image data of the wafer W with the image data of the nondefective wafer stored in the database (not shown) to inspect whether or not there is any abnormity (defection) in the wafer W. Further, the inspection of the wafer W is carried out according to each chip region, and it is determined to be abnormal when the difference between the signal intensity (brightness value) of the inspection object wafer W and the signal intensity (brightness value) of the nondefective wafer is greater than a predetermined threshold value. On the other hand, it is determined to be normal when the difference between the signal intensities (brightness values) is smaller than the threshold value. Then, the inspection result from the image processing section  41  and the image of that wafer W are outputted and displayed on the display section  42 . 
         [0083]    When the inspection apparatus  1  of the first embodiment is used to obtain an image based on the diffracted light from the entire surface of the wafer W, then the obtained image has a brightness in accordance with the intensity of the diffracted light (to be referred to hereinbelow as a diffraction image). The diffracted light intensity changes according to the distribution of diffraction efficiency. Thus, when the regularly formed pattern A is uniformly laid out, then localized change in diffraction efficiency does not occur. On the contrary, when the pattern A changes in shape in some region, then the diffraction efficiency also changes in that region. As a result, the corresponding region of the diffraction image changes in brightness, and thereby it is possible to detect the change of the pattern in the corresponding region. Further, the change of the pattern refers to the change of the pattern A in line width (hole diameter) or cross-sectional shape. 
         [0084]    The distance or length on the wafer W corresponding to one pixel (pixel size) of the diffraction image obtained by the imaging section  35  is, for example, 300 μm, which is, generally, much greater than the dimension of the pattern A or the repetitive pitch. However, the brightness of each pixel in the diffraction image corresponds to an average intensity of the diffracted light from the pattern of the corresponding region on the wafer W. When the pattern A of the wafer W is not normally formed due to some problems in the exposure device and the like for forming the pattern, then it is conceivable that the entire pattern of the region occupying a certain area deforms in the same manner. Therefore, even though the pixel size is greater than the dimension of the pattern A or the repetitive pitch, it is still possible to detect abnormity (defection) of the corresponding region. 
         [0085]    For example, when it is set to emit a light (illumination light) of the wavelength 546 nm (e-ray) from the illumination unit  21  based on a command from the control section  40 , and when the diffraction condition is satisfied, then the imaging section  35  can obtain a diffraction image. From this diffraction image, as described above, it is possible to detect abnormity (defection) in the pattern A. However, because the light of the wavelength 546 nm is not transmissive through silicon, the detectable abnormities are only those in the vicinity of the surface of the wafer W. That is, the detectable abnormities are abnormity in the hole diameter near the surface of the wafer W, abnormity in the cross-sectional shape of the holes near the surface of the wafer W, etc. 
         [0086]    When it is set to emit a light including infrared of the wavelength 700 nm or longer, for example, a light (illumination light) of the wavelength 1100 nm, from the illumination unit  21  based on a command from the control section  40 , and when the diffraction condition is satisfied, then a diffraction image can be obtained in the same manner. On this occasion, because the light of the wavelength 1100 nm is transmissive through the silicon substrate (thickness 725 μm) used in the first embodiment, it is possible to detect abnormities (defections) even in deep parts of the holes. The reason is that although the light of the wavelength 1100 nm is transmitted through the silicon, diffracted light (diffraction phenomenon) still occurs in the boundary (interface) between the part of silicon and the part of holes of the wafer W. 
         [0087]    When the wafer W formed with TSVs is inspected by irradiating, with infrared light, the wafer W held by a conventional wafer holder (of which material is ceramic or aluminum alloy), then part of the irradiated infrared light is transmitted to the opposite side of the wafer W. Therefore, other than the diffracted light from the inspection object wafer, reflected and scattered light is also received from the edges and the like of the support portions (suction grooves) of the wafer holder, and becomes noise in the image of the wafer W, thereby being liable to obstruct the inspection. 
         [0088]    In contrast to this, in the wafer holder  10  of the first embodiment, each of the protruding support portions  11  is configured to extend continuously from the part supporting one end of the wafer W to the part supporting the other end, without any line or plane orthogonal to the incidence plane of the illumination light to the wafer W in the portion of the wafer holder  10  supporting the aforementioned observation area T 1 . In other words, in the portion of the wafer holder  10  supporting the aforementioned observation area T 1 , each of the protruding support portions  11  (and groove portions  12 ) is formed to intersect the incidence plane of the illumination light at an acute angle or obtuse angle. For example, in an area overlapping the observation area T 1  in planar view, the lateral sides  11   b  and edge lines  11   c  of the support portions  11  are formed to be not orthogonal to the incidence plane of the illumination light. Further, it is desirable to form an angle not exceeding 45 degrees (including zero degrees) between each of the protruding support portions  11  (and groove portions  12 ) and the incidence plane of the illumination light. Further, the plane orthogonal to the incidence plane of the illumination light refers to such a plane that when it is flat then its perpendicular is parallel to the incidence plane, but when it is curved then its normal is parallel to the incidence plane. By virtue of this, even when any reflected and scattered infrared light arises from the edges (the parts of the edge lines  11   c ) of the protruding support portions  11 , because the perpendicular to the edges does not extend parallel to the incidence plane of the illumination light (that is, toward the light receiving system  30 ), most of the reflected and scattered light arising from the edges proceeds in a different direction from the propagation direction of the diffracted light arising from the pattern A (that is, the light-receiving direction of the light receiving system  30 ). Therefore, because the reflected and scattered light arising from the edges of the protruding support portions  11  becomes less likely to reach the light receiving system  30 , in the observation area T 1  of the wafer W, it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  10 . Further, because it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  10 , based on the image of the wafer W with little noise, it becomes possible to inspect whether or not there is any abnormity (defection) in the wafer W, thereby allowing the inspection precision to be improved. 
         [0089]    Further, the relief portions  16  formed with the wafer holder  10  are also arranged to not have any lines or planes orthogonal to the incidence plane of the illumination light. Likewise, in this case, too, even when any reflected and scattered infrared light arises from the edges of the relief portions  16 , because the perpendicular to the edges does not extend parallel to the incidence plane of the illumination light (that is, toward the light receiving system  30 ), most of the reflected and scattered light arising from the edges of the relief portions  16  proceeds in a different direction from the propagation direction of the diffracted light arising from the pattern A (that is, the light-receiving direction of the light receiving system  30 ). Therefore, because the reflected and scattered light arising from the edges of the relief portions  16  becomes less likely to reach the light receiving system  30 , in the observation area T 1  of the wafer W, it is possible to more reliably prevent detection of the reflected and scattered light arising from the wafer holder  10 , thereby allowing the inspection precision to be improved more. 
         [0090]    Further, the support portions  11  are each formed into an approximate cuboid, and extend along the incidence plane of the illumination light. Therefore, the lateral sides  11   b  and edge lines  11   c  of the support portions  11  are parallel to but not orthogonal to the incidence plane of the illumination light. By virtue of this, it is possible to more reliably prevent detection of the reflected and scattered light arising from the wafer holder  10 , thereby allowing the inspection precision to be improved more. 
         [0091]    Further, the tilt mechanism  9  is provided to tilt (rotate) the wafer holder  10  around an axis vertical to the incidence plane of illumination light, and thus it is possible to change the incident angle and the like of the illumination light to the wafer W. Therefore, it is possible to detect the desired diffracted light from the wafer W without detecting the reflected and scattered light arising from the wafer holder  10 , thereby allowing the inspection precision to be improved more. 
         [0092]    Further, when it is configured to use the illumination light including infrared of the wavelength 700 nm or longer, then it is possible to use an ordinary image sensor to detect the light from the wafer W (to take an image of the wafer W), whereby the inspection can be carried out with a simple and convenient configuration. Further, because the sensitivity of the image sensor to near-infrared may decrease so as to lower the signal-noise ratio, a cooled image sensor can be used as necessary to raise the signal-noise ratio. 
         [0093]    Further, the wafer holder  10  of the first embodiment is configured to suck and hold the wafer W by sucking the air from the pressure reduction spaces S 1  formed by the wafer W and support portions  11  to reduce the pressures inside the pressure reduction spaces S 1 , and the suction holes  14  through which the air is sucked are provided in the portion of the wafer holder  10  supporting the other area than the observation area T 1  (in the groove portions  12  and in the vicinity of the connection portions  13 ). In this manner, by arranging the suction holes  14  outside of the observation area T 1 , it is possible to suck and hold the wafer W without detecting the reflected and scattered light arising from the edges and the like of the suction holes  14 , in the observation area T 1 . 
         [0094]    Further, the plurality of connection portions  13  are each formed to connect the corresponding ends of one adjacent pair of the support portions  11  in a portion of the wafer holder  10  supporting one end or the other end of the wafer W and, by those connection portions  13 , both ends of each of the groove portions  12  are closed up to prevent inflow of air or gas into the aforementioned pressure reduction spaces S 1  from outside. By virtue of this, by arranging the connection portions  13  outside of the portion of the wafer holder  10  supporting the observation area T 1 , it is possible to more reliably suck and hold the wafer W without detecting the reflected and scattered light arising from the edges and the like of the connection portions  13 , in the observation area T 1 . 
         [0095]    Further, in the first embodiment described above, the two relief portions  16  formed at lateral sides of the wafer holder  10  are configured to extend respectively along the incidence plane of the illumination light. However, they are not limited to this configuration. As shown in  FIG. 8  for example, four relief portions  86  may alternatively be formed at lateral sides of a wafer holder  80  at regular intervals (90° intervals). Because each of the relief portions  86  shown in  FIG. 8  has an arc-like cutaway, part of the arc may become a line or plane orthogonal to the incidence plane of the illumination light. However, there is no obstruction because the relief portions  86  are all located out of the observation area T 1 . Being configured in this manner, it is possible to arrange the four holding members  77  of the wafer holding device  73  at regular intervals (90° intervals) along the edge of the wafer W, so as to enable the wafer holding device  73  to stably hold edge portions of the wafer W. Further, the wafer holder  80  shown in  FIG. 8  has the same configuration as the wafer holder  10  shown in  FIGS. 1(   a ) and  1 ( b ) except for the relief portions  86 , and therefore reference numerals are omitted except for the relief portions  86 . Further, each of the relief portions  86  is formed with a curved surface to fit the shape of the holding members  77 , and positioned outside of the portion of the wafer holder  10  supporting the observation area T 1 . 
         [0096]    Further, in the first embodiment described above, the support portions  11  are each formed into an approximate cuboid to extend along the incidence plane of the illumination light, and the lateral sides  11   b  of the support portions  11  are flat surfaces approximately vertical to the support surfaces  11   a  respectively. However, the support portions  11  are not limited to this configuration. As shown in  FIG. 9  for example, lateral sides  91   b ,  91   b  at two sides of each support portion  91  may be formed into curved surfaces approximately vertical to the support surface, and be connected at an approximately acute angle with each other at both ends of each support portion  91 . In such configuration, because there is no line or plane orthogonal to the incidence plane of the illumination light in the portion of a wafer holder  90  supporting the observation area T 1  of the wafer W, it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  90 , thereby allowing the inspection precision to be improved. Further, in the wafer holder  90  shown in  FIG. 9 , connection portions (not shown) may also be provided to connect corresponding ends of the support portions  91 , so as to close up both ends of each groove portion  92  on the outside of the portion of the wafer holder  90  supporting the observation area T 1 . By virtue of this, because no air or gas flows from outside into the pressure reduction spaces described in the aforementioned first embodiment, it is possible to more reliably suck and hold the wafer W. Further, suction holes (not shown) may also be formed in the groove portions  92 , respectively, on the outside of the portion of the wafer holder  90  supporting the observation area T 1 . 
         [0097]    Further, as shown in  FIG. 10 , each support portion  101  may be formed into a tapered shape such that lateral sides  101   b  of each support portion  101  are inclined obliquely to a support surface  101   a . In such configuration, it is also possible to obtain the same effect as in the case described in the aforementioned first embodiment. Further, in this case as shown by the two-dot chain lines in  FIG. 10 , without being limited to the bottoms of groove portions  102 , suction holes  104  may also be formed in the lateral sides  101   b  of the support portions  101 . 
         [0098]    Further, in the first embodiment described above, the suction holes  14  are provided to suck the air from the pressure reduction spaces S 1  formed by the wafer W and support portions  11 . However, without being limited to this configuration, the wafer holder may also be formed of a porous material (for example, a porous metal, porous ceramics, etc.), and the vacuum source (not shown) may be used to suck the air from the pressure reduction spaces formed by the wafer W and support portions via tiny air holes or pores formed in the wafer holder. In such configuration, it is also possible to reduce the pressures inside the pressure reduction spaces, so as to suck and hold the wafer W on the wafer holder  10 . 
         [0099]    Further, in the first embodiment described above, the plurality of connection portions  13  are each formed to connect the corresponding ends of one adjacent pair of the support portions  11  at a portion of the wafer holder  10  supporting one end or the other end of the wafer W and, by those connection portions  13 , both ends of each of the groove portions  12  are closed up to prevent inflow of air or gas into the aforementioned pressure reduction spaces S 1  from outside. However, the present invention is not limited to such configuration. For example, between the corresponding ends of each adjacent pair of the support portions  11 , a pressure reduction auxiliary portion may be provided to close up part of both ends of the corresponding groove portion  12 , so as to prevent inflow of air or gas into the pressure reduction spaces S 1  from outside. 
         [0100]    Next, referring to  FIGS. 11(   a ) and  11 ( b ), a second embodiment of the inspection apparatus will be explained. The inspection apparatus of the second embodiment has the same configuration as the inspection apparatus  1  of the first embodiment except for the wafer holder. Therefore, the same reference numeral is assigned to each of the other portions as in the first embodiment while detailed explanation will be omitted. A wafer holder  200  of the second embodiment primarily includes a planate electrode (not shown), and a pair of insulation members, i.e., a dielectric layer  210  and a supportive layer  220 , oppositely arranged to sandwich the electrode, and is configured to use electrostatic force to suck and hold the wafer W by applying a predetermined voltage to the electrode with the wafer W being placed on the dielectric layer  210 . 
         [0101]    The dielectric layer  210  and supportive layer  220  are formed into an approximately circular disk to fit the shape of the wafer W by using an insulation material such as ceramic or the like. On the upper-end portion (front-end portion) of the dielectric layer  210 , there are formed a plurality of protruding support portions  211  to contact with the wafer W when supporting the wafer W, and a plurality of groove portions  212  formed between the plurality of support portions  211  and apart from the wafer W. 
         [0102]    Each of the support portions  211  is formed into an approximate cuboid to continuously support the wafer W from one end to the other end, and arranged to extend along an incidence plane of the illumination light to the wafer W. Further, the plurality of support portions  211  are formed to be approximately parallel to each other, as well as formed to let the plurality of groove portions  212  be approximately parallel to each other between the respective support portions  211 . Therefore, with each of the support portions  211 , there are formed a support surface  211   a  which is a flat surface to contact with the back side of the wafer W, lateral sides  211   b  approximately vertical to the support surface  211   a , an edge line  211   c  which is an intersectional line between the support surface  211   a  and the lateral sides  211   b , and the like, all of which extend along the incidence plane of the illumination light. 
         [0103]    Further, a black coating capable of absorbing infrared rays is applied to the surface of the upper-end portion (front-end portion) of the dielectric layer  210  where the support portions  211 , groove portions  212  and the like are formed. Further, without being limited to a black coating, it is possible to form a layer of any suitable infrared absorber on the upper-end surface of the dielectric layer  210 . For example, as the infrared absorber, it is also possible to apply or attach carbon black, diimmonium salt, aminium salt, or the like, to the surface of the dielectric layer  210 . Further, black SiC (silicon carbide) may also be used to form the dielectric layer  210 . 
         [0104]    At the left and right sides of the dielectric layer  210  (and supportive layer  220 ), a pair of relief portions  216  are formed to prevent the wafer W from contact with the holding members  77  of the wafer holding device  73  when the third transport device  71  transports the wafer W onto the wafer holder  200  (the dielectric layer  210 ). These two relief portions  216 ,  216  are edges which form cutaways of the approximately circular-disk-like dielectric layer  210  (and supportive layer  220 ), and the wafer holder  200  is disposed such that the lateral sides and edge lines (of the dielectric layer  210  and supportive layer  220 ) forming the respective relief portions  216  may extend along the incidence plane of the illumination light. 
         [0105]    With the wafer holder  200  of the second embodiment configured in the above manner, in order to chuck the back side of the wafer W, the predetermined voltage is applied to the electrode (not shown) with the back side of the wafer W in contact with the dielectric layer  210  (support portions  211 ). By virtue of this, the wafer W is sucked and held on the wafer holder  200  by using electrostatic force. On the other hand, in order to release the chucking of the back side of the wafer W from the wafer holder  200 , it is only necessary to turn off the power to the electrode after the tilt mechanism  9  restores the wafer holder  200  to an approximately horizontal state. 
         [0106]    In the wafer holder  200  of the second embodiment, each of the protruding support portions  211  is configured to extend continuously from the part supporting one end of the wafer W to the part supporting the other end, without any line or plane orthogonal to the incidence plane of the illumination light to the wafer W in the portion of the wafer holder  200  supporting the observation area T 1  of the wafer W. In other words, in the portion of the wafer holder  200  supporting the aforementioned observation area T 1 , each of the protruding support portions  211  (and groove portions  212 ) is formed to intersect the incidence plane of the illumination light at an acute angle or obtuse angle. For example, the lateral sides  211   b  and edge lines  211   c  of the support portions  211  are formed to be not orthogonal to the incidence plane of the illumination light. Therefore, in the same manner as in the first embodiment, it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  200 , thereby allowing the inspection precision to be improved. 
         [0107]    Further, according to the second embodiment, in the same manner as in the first embodiment, because the wafer holder  200  is formed with the relief portions  216 , it is possible to more reliably prevent detection of the reflected and scattered light arising from the wafer holder  200 , thereby allowing the inspection precision to be improved more. Further, still in the same manner as in the first embodiment, because the support portions  211  are each formed into an approximate cuboid to extend along the incidence plane of the illumination light, it is possible to more reliably prevent detection of the reflected and scattered light arising from the wafer holder  200 , thereby allowing the inspection precision to be improved more. 
         [0108]    Further, in the second embodiment described above, each of the support portions  211  is formed into an approximate cuboid to continuously support the wafer W from one end to the other end. However, without being limited to this configuration, as shown in  FIG. 12  for example, each support portion  261  may be formed into a rhombic protrusion. Further, on a dielectric layer  260  of a wafer holder  250  shown in  FIG. 12 , there are formed the plurality of support portions  261  to contact with the wafer W when supporting the wafer W, and a separate portion  262  apart from the wafer W. Each of the support portions  261  is formed into the rhombic protrusion to partially support the wafer W, and arranged such that the long diagonal of a rhombic support surface  261   a  may extend along the incidence plane of the illumination light to the wafer W. Further, the plurality of support portions  211 ,  211 , . . . are arranged to align in a plurality of rows parallel to the incidence plane of the illumination light. Therefore, with each of the support portions  261 , there are formed lateral sides  261   b  approximately vertical to the rhombic support surface  261   a , an edge line  261   c  which is an intersectional line between the support surface  261   a  and the lateral sides  261   b , and the like, all of which extend obliquely (not vertically) to the incidence plane of the illumination light. Further, when a chamfering process or the like is carried out to prevent burrs on the vertexes of the edge lines  261   c , then it is possible to form planes or lines orthogonal to the incidence plane of the illumination light. Therefore, it is desirable to arrange the vertexes of the edge lines  261   c  into aftermentioned streets Ws. 
         [0109]    By virtue of this, even when any reflected and scattered infrared light arises from the edges (the parts of the edge lines  211   c ) of the protruding support portions  261 , because the perpendicular to the edges does not extend parallel to the incidence plane of the illumination light (that is, toward the light receiving system  30 ), most of the reflected and scattered light arising from the edges proceeds in a different direction from the propagation direction of the diffracted light arising from the pattern A (that is, the light-receiving direction of the light receiving system  30 ), thereby becoming less likely to reach the light receiving system  30 . In this manner, in the portion of the wafer holder  250  supporting the observation area T 1  of the wafer W, the wafer holder  250  shown in  FIG. 12  is configured not to have any lines or planes orthogonal to the incidence plane of the illumination light to the wafer W (the lateral sides  261   b  and edge line  261   c  of each of the support portions  261  are not orthogonal to the incidence plane of the illumination light). Therefore, it is possible to obtain the same effect as the aforementioned second embodiment. 
         [0110]    Further, in the second embodiment described above, like the first embodiment, it is also possible either to form four relief portions at lateral sides of the wafer holder at regular intervals (90° intervals), or to form each of the support portions into a tapered shape. 
         [0111]    Next, referring to  FIGS. 13(   a ) and  13 ( b ), a third embodiment of the inspection apparatus will be explained. The inspection apparatus of the third embodiment has the same configuration as the inspection apparatus  1  of the first embodiment except for the wafer holder. Therefore, the same reference numeral is assigned to each of the other portions as in the first embodiment while detailed explanation will be omitted. Using ceramic or the like, a wafer holder  300  of the third embodiment is formed into an approximately circular disk to fit the shape of the wafer W. The upper-end portion (front-end portion) of the wafer holder  300  is formed with a plurality of protruding support portions  311  to contact with the wafer W when supporting the wafer W, and a plurality of groove portions  312  which are formed between these plurality of support portions  311  and apart from the wafer W. 
         [0112]    In the same manner as in the first embodiment, each of the support portions  311  is formed into an approximate cuboid to continuously support the wafer W from one end to the other end, and arranged to extend along an incidence plane of the illumination light to the wafer W. Further, still in the same manner, the plurality of support portions  311  in the portion supporting the observation area T 1  are formed to be approximately parallel to each other, as well as formed to let the plurality of groove portions  312  be approximately parallel to each other between the respective support portions  311 . 
         [0113]    Then, with the wafer W being supported by the wafer holder  300 , a pressure reduction space S 2  is formed with each of the groove portions  312  to be enclosed by the wafer W, and the support portions  311  positioned on both sides of the corresponding groove portion  312 . By sucking the air from the pressure reduction spaces S 2  formed respectively with the groove portions  312  to reduce the pressures inside the pressure reduction spaces S 2 , the wafer W is sucked and held on the wafer holder  300 . Further, a plurality of connection portions  313  are each formed to connect the corresponding ends of one adjacent pair of the support portions  311  at a portion of the wafer holder  300  supporting one end or the other end of the wafer W and, by those connection portions  313 , both ends of each of the groove portions  312  are closed up to prevent inflow of air or gas into the above pressure reduction spaces S 2  from outside. 
         [0114]    In a central portion of the wafer holder  300  of the third embodiment, a rhombic passage hole  316  is formed to enable a chuck portion  360  of a transfer stage  350  to pass through. Therefore, due to the passage hole  316 , there are disconnected parts in the support portions  311  and groove portions  312  passing through the central portion of the wafer holder  300 . Hence, a plurality of hole-side connection portions  317  are each formed to connect one adjacent pair of the support portions  311  at a portion in connection with the passage hole  316 . Thus, the hole-side connection portions  317  close up the disconnected parts of the groove portions  312  due to the passage hole  316  so as to prevent inflow of air or gas into the above pressure reduction spaces S 2  from outside. Further, each of the hole-side connection portions  317  is formed into a wall shape extending along the periphery of the passage hole  316 . 
         [0115]    Further, in the bottoms of the groove portions  312 , suction holes  314  are formed for sucking air from the respective pressure reduction spaces S 2 . The suction holes  314  are arranged respectively in the bottoms of the groove portions  312 , and in the vicinity of the connection portions  313 , i.e., in the portion of the wafer holder  300  supporting the area other than the observation area T 1  (the area outside of the observation area T 1 ), and formed to extend downward from the bottoms of the groove portions  312 . The lower ends of the suction holes  314  are connected respectively to an internal passage  315  formed inside the wafer holder  300 , while the internal passage  315  is connected to the unshown vacuum source via a vacuum piping (not shown) fitted below the wafer holder  10 . 
         [0116]    Further, outer support portions  311 ′ are each formed into an arc shape according to the outer-periphery shape of the wafer W so as to support areas of the left and right ends of the wafer W in  FIGS. 13(   a ) and  13 ( b ), while being each connected to both ends of the adjacent support portion  311  so as to form a semicircular outer groove portion  312 ′ on the inner-periphery side. A pressure reduction space S 2  is also formed with each of these outer groove portions  312 ′ to be enclosed by the wafer W, and the support portion  311  and support portion  311 ′ positioned on both sides of the corresponding outer groove portion  312 ′, while in the bottoms of the outer groove portions  312 ′, outer suction holes  314 ′ are formed for sucking air from the corresponding pressure reduction spaces S 2 . 
         [0117]    Further, a black coating capable of absorbing infrared rays is applied to the surface of the upper-end portion (front-end portion) of the wafer holder  300  where the support portions  311 , groove portions  312  and the like are formed. Further, without being limited to a black coating, it is possible to form a layer of any suitable infrared absorber on the upper-end surface of the wafer holder  300 . For example, as the infrared absorber, it is also possible to apply or attach carbon black, diimmonium salt, aminium salt, or the like, to the surface of the wafer holder  300 . Further, black SiC (silicon carbide) may also be used to form the wafer holder  300 . 
         [0118]    Below the wafer holder  300 , the transfer stage  350  is provided to receive the wafer W transported there by the third transport device  71  and transfer the same to the wafer holder  300 . The transfer stage  350  is configured to include a chuck portion  360  which sucks and holds the wafer W, a raising and lowering portion  370  which vertically moves (raises and lowers) the chuck portion  360 . The chuck portion  360  is formed into a rhombus a little smaller than the passage hole  316  of the wafer holder  300  and, in the same manner as the wafer holder  300 , configured to have support portions, groove portions, connection portions and the like to be capable of sucking the wafer W. 
         [0119]    The upper end of a vertically extending support shaft  365  is connected to the lower end of the chuck portion  360 , while the lower end of the support shaft  365  is connected to a plate-like raising and lowering base  366  fitted on the nut of a ball screw  372 . By virtue of this, the chuck portion  360  is connected with the raising and lowering portion  370  via the support shaft  365  and raising and lowering base  366 . The raising and lowering portion  370  is configured to have a motor  371 , and the ball screw  372  which receives the rotary force of the motor  371  to vertically move the raising and lowering base  366 , so as to be capable of vertically moving (raising and lowering) the chuck portion  360  along with the raising and lowering base  366  and support shaft  365 . 
         [0120]    With the wafer holder  300  of the third embodiment configured in the above manner, in order to receive the wafer W transported by the third transport device  71 , first, the chuck portion  360  of the transfer stage  350  is inserted through the passage hole  316  of the wafer holder  300  and raised up to the first transfer position set to be above and apart from the wafer holder  300 . Then, at the first transfer position, while the third transport device  71  (wafer holding device  73 ) releases the holding of the edge portions of the wafer W, the chuck portion  360  chucks the back side of the wafer W. Next, the wafer W held by the chuck portion  360  is lowered along with the chuck portion  360  down to the wafer holder  300 , where the chuck portion  360  releases the chucking of the back side of the wafer W while the wafer holder  300  chucks the back side of the wafer W. Then, by lowering the chuck portion  360  below the wafer holder  300 , it is possible to hold the wafer W on the wafer holder  300  while causing the tilt mechanism  9  to tilt the wafer holder  300 . 
         [0121]    On the other hand, in order to transfer the wafer W from the wafer holder  300  to the third transport device  71 , first, the chuck portion  360  of the transfer stage  350  is raised up to the same height as the wafer holder  300 , where the wafer holder  300  releases the chucking of the back side of the wafer W while the chuck portion  360  chucks the back side of the wafer W. Then, the wafer W held by the chuck portion  360  is raised along with the chuck portion  360  up to the first transfer position, where the chuck portion  360  releases the chucking of the back side of the wafer W while the third transport device  71  (wafer holding device  73 ) holds edge portions of the wafer W. Further, the wafer holder  300  as well as the chuck portion  360  chucks the back side of the wafer W and releases the chucking of the back side of the wafer W in the same manner as in the first embodiment. 
         [0122]    The wafer holder  300  of the third embodiment is similar to the wafer holder  10  of the first embodiment in the shapes and the like of the support portions  311  and groove portions  312 , but different therefrom in that the rhombic passage hole  316  is formed in the central portion. This passage hole  316  is arranged such that the diagonals of the rhombus may extend along the incidence plane of the illumination light to the wafer W, while the lateral sides of the passage hole  316 , the edge lines along the edges of the passage hole  316 , and the like are configured to extend obliquely (not vertically) to the incidence plane of the illumination light. By virtue of this, even when any reflected and scattered infrared light arises from the edges (the parts of the edge lines) of the passage hole  316  and hole-side connection portions  317 , because the perpendicular to the edges does not extend parallel to the incidence plane of the illumination light (that is, toward the light receiving system  30 ), most of the reflected and scattered light arising from the edges proceeds in a different direction from the propagation direction of the diffracted light arising from the pattern A (that is, the light-receiving direction of the light receiving system  30 ), thereby becoming less likely to reach the light receiving system  30 . In this manner, in the portion of the wafer holder  300  supporting the observation area T 1  of the wafer W, the wafer holder  300  of the third embodiment is configured not to have any lines or planes orthogonal to the incidence plane of the illumination light to the wafer W. Therefore, in the same manner as in the first embodiment, it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  300 , thereby allowing the inspection precision to be improved. Further, the passage hole  316  (as well as the chuck portion  360 ) is not necessarily rhombic, but may take on any shape as far as it is arranged in the observation area T 1  without forming any lines or planes orthogonal to the incidence plane of the illumination light to the wafer W. For example, the passage hole  316  (as well as the chuck portion  360 ) may be formed either into an octagon, or a tetragon which superimposes the bases of two isosceles triangles different in height from each other. Further, it is not necessary to arrange the passage hole  316  (as well as the chuck portion  360 ) such that the diagonals of the rhombus may extend along the incidence plane of the illumination light to the wafer W, but it is possible to arrange the same at any angle as far as it is arranged in the observation area T 1  without forming any lines or planes orthogonal to the incidence plane of the illumination light to the wafer W. For example, the passage hole  316  (as well as the chuck portion  360 ) may be arranged to be a few degrees (5 to 10 degrees) inclined from the arrangement shown in  FIG. 13(   a ). 
         [0123]    Further, in the third embodiment described above, it is configured to suck and hold the wafer W on the wafer holder  300  by sucking the air from the pressure reduction spaces S 2  enclosed by the support portions  311  and wafer W to reduce the pressures inside the pressure reduction spaces S 2 . However, the present invention is not limited to this but, as described in the second embodiment, may be configured to use electrostatic force to suck and hold the wafer W on the wafer holder. Further, in the same manner, the chuck portion  360  of the transfer stage  350  may also be configured to use electrostatic force to suck and hold the wafer W. 
         [0124]    Further, in the third embodiment described above, like the first embodiment, it is also possible either to form each of the support portions into a tapered shape, or to form the wafer holder of a porous material. Further, instead of the connection portions, pressure reduction auxiliary portions may be provided to prevent inflow of air or gas into the pressure reduction spaces S 2  from outside. 
         [0125]    Next, referring to  FIGS. 14 and 15 , a fourth embodiment of the inspection apparatus will be explained. The inspection apparatus of the fourth embodiment has the same configuration as the inspection apparatus  1  of the first embodiment except for the wafer holder. Therefore, the same reference numeral is assigned to each of the other portions as in the first embodiment while detailed explanation will be omitted. Further, in the fourth embodiment, an observation area T 2  refers to an area of the wafer W where chips Wc (the pattern A) are formed, and streets Ws formed between the respective chips Wc are supposed to be not included in the observation area T 2 . Using ceramic or the like, a wafer holder  400  of the fourth embodiment is formed into an approximately circular disk to fit the shape of the wafer W. The upper-end portion (front-end portion) of the wafer holder  400  is formed with protruding support portions  411  to contact with the wafer W when supporting the wafer W, and separate portions  412  apart from the wafer W. 
         [0126]    As shown in  FIG. 14 , the support portions  411  are formed into parallel crosses extending in a crisscross manner so as to contact with the back sides of the streets Ws of the wafer W. Further, the support portions  411  are smaller in width than the streets Ws. Further, because generally the chips Wc do not change in size with each wafer W of the same type, it is possible to uniformly determine the width and interval of the support portions  411  formed in parallel crosses. The plurality of separate portions  412  are formed to be partitioned by the support portions  411  formed in parallel crosses. 
         [0127]    Then, as shown in  FIG. 15 , with the wafer W being supported by the wafer holder  400 , a pressure reduction space S 3  is formed with each of the separate portions  412  to be enclosed by the wafer W and the support portions  411 . By sucking the air from the pressure reduction spaces S 3  formed respectively with the separate portions  412  to reduce the pressures inside the pressure reduction spaces S 3 , the wafer W is sucked and held on the wafer holder  400 . Further, as shown in  FIG. 14 , an annular connection portion  413  is formed to connect the corresponding ends of the adjacent support portions  411  at a portion of the wafer holder  400  supporting the peripheral portion of the wafer W (where the chips Wc are not formed) and, by this connection portion  413 , the abovementioned pressure reduction spaces S 3  are also formed with the separate portions  412  positioned in the peripheral portion of the wafer holder  400 . 
         [0128]    Further, as shown in  FIG. 15 , in the bottom of each of the separate portions  412 , a suction hole  414  is formed for sucking air from the corresponding pressure reduction space S 3 . The suction holes  414  are formed to extend downward from the bottoms of the separate portions  412 , and connected respectively to the unshown vacuum source via an internal passage and vacuum piping (not shown) of the wafer holder  400 . Further, the suction holes  414  may also be each formed into a rhombus whose diagonals extend along the incidence plane of the illumination light to the wafer W. 
         [0129]    Further, a black coating capable of absorbing infrared rays is applied to the surface of the upper-end portion (front-end portion) of the wafer holder  400  where the support portions  411 , separate portions  412  and the like are formed. Further, without being limited to a black coating, a layer of any suitable infrared absorber may be formed on the upper-end surface of the wafer holder  400  as necessary. For example, as the infrared absorber, it is also possible to apply or attach carbon black, diimmonium salt, aminium salt, or the like, to the surface of the wafer holder  400 . Further, black SiC (silicon carbide) may also be used to form the wafer holder  400 . 
         [0130]    With the wafer holder  400  of the fourth embodiment configured in the above manner, in order to chuck the back side of the wafer W, with the back side of the wafer W being in contact with the wafer holder  400 , the unshown vacuum source is used to suck the air, via the suction holes  414 , from the pressure reduction spaces S 3  formed respectively with the separate portions  412  of the wafer holder  400 . By virtue of this, the air pressures inside the pressure reduction spaces S 3  are reduced, and thus the wafer W is sucked and held on the wafer holder  400 . On the other hand, in order for the wafer holder  400  to release the chucking of the back side of the wafer W, after the tilt mechanism  9  restores the wafer holder  400  to an approximately horizontal state, the unshown gas supply device, switching valve and the like are used to supply air or a gas from the suction holes  414  to the aforementioned pressure reduction spaces S 3  formed in the wafer holder  400 . By virtue of this, the reduced pressures inside the pressure reduction spaces S 3  return to the atmospheric pressure, thereby releasing the wafer W from being sucked by the wafer holder  400 . 
         [0131]    In the wafer holder  400  of the fourth embodiment, the protruding support portions  411  are formed in parallel crosses to contact with the back sides of the streets Ws which are not included in the observation area T 2 , and configured not to have any lines or planes orthogonal to the incidence plane of the illumination light to the wafer W in the portion of the wafer holder  400  supporting the observation area T 2  of the wafer W. By virtue of this, even when the reflected and scattered light arising from the edges and the like of the support portions  411  reaches the imaging section  35 , it is only reflected in the part of the streets Ws which are not included in the observation area T 2 , but not reflected in the observation area T 2  in which the chips Wc are formed. Therefore, in the same manner as in the first embodiment, it is possible to prevent detection of the reflected and scattered light arising from the wafer holder  400 , thereby allowing the inspection precision to be improved. Further, because the support portions  411  can be arranged uniformly, it is possible to suck and hold the wafer W without giving rise to any deflection. 
         [0132]    Further, in the fourth embodiment described above, it is configured to suck and hold the wafer W on the wafer holder  400  by sucking the air from the pressure reduction spaces S 3  enclosed by the support portions  411  and wafer W to reduce the pressures inside the pressure reduction spaces S 3 . However, without being limited to this configuration, it may also be configured to use electrostatic force to suck and hold the wafer W on the wafer holder as described in the second embodiment. Further, when the streets Ws are narrow, then it is necessary to narrow the support portions  411  too. When the streets Ws are each narrower than a predetermined width, then it becomes practically difficult to use the streets Ws for the support. Hence, it can be said that the fourth embodiment is effective for the streets Ws which are each broader than the predetermined width. On the other hand, in the fourth embodiment, even when the wafer W is turned over and then held by the wafer holder, because the support portions  411  still do not overlap the pattern, the diffraction inspection may also be carried out from the surface (back surface) on the opposite side to the surface (front surface) where the pattern A is formed. 
         [0133]    Further, in each of the abovementioned embodiments, the wafer holding device  73  holds edge portions of the wafer W by rotating the holding members  77  where the engagement grooves  77   a  are formed. However, without being limited to this configuration, for example, the wafer holding device  73  may include a pair of holding members which are slidable in mutually opposite horizontal directions, a pair of rod-like members on which rack gears are formed and which are connected respectively to the holding members, a pinion gear which has engaged the respective rack gears, and a motor which rotationally drives the pinion gear, to let the holding members hold edge portions of the wafer W or release the holding of the edge portions of the wafer W by causing the motor to rotate the pinion gear so as to slide the pair of rod-like members and the pair of holding members in the horizontal directions. Further, when there is no negative influence on the surface side of the wafer W, then it is also possible to chuck the surface of the wafer W. 
         [0134]    Further, in each of the abovementioned embodiments, the wafer holder sucks and holds the wafer W (from the back side of the wafer W) with its surface facing upward. However, without being limited to this configuration, the wafer W may also be turned over and then held by the wafer holder, and the diffraction inspection may be carried out from the surface (back surface) on the opposite side to the surface (front surface) where the pattern A is formed. On this occasion, further, it is desirable to use a thin-film protector to cover and protect the surface of the wafer W where the pattern A is formed. On this occasion, furthermore, it is desirable to grind the back surface of the wafer W into a specular surface. Moreover, it is desirable to control the back surface of the wafer W so as not to let any dirt and the like adhere thereto. The reason is that because the illumination light passes through the back surface of the wafer W twice, when this surface is a scattering surface (not ground), or when some dirt and the like adhere to this surface, then the inspection is subject to encounter with obstruction. 
         [0135]    Further, in each of the abovementioned embodiments, the diffracted light arising from the pattern A of the wafer W is detected to carry out the inspection of the wafer W. However, without being limited to this configuration, for example, it is also possible to detect a state change in the polarized light due to the structural birefringence arising from the pattern A of the wafer W. It is possible to detect a state change in the polarized light due to the structural birefringence by arranging a polarization element in each of the optical paths of the illumination system  20  and light receiving system  30  to form a crossed-Nicol relationship between the polarization element of the illumination system  20  and the polarization element of the light receiving system  30 . Further, sensitivity may be improved by deviating the relationship between the polarization element of the illumination system  20  and the polarization element of the light receiving system  30  from the crossed Nicol according the polarization state of the reflected light. Further, for example, it is also possible to detect the regular reflection light or scatted light from the front surface (or back surface) of the wafer W. 
         [0136]    Further, in each of the abovementioned embodiments, the illumination system  20  (illumination unit  21 ) is configured to irradiate the wafer W with the illumination light of a specific wavelength. However, without being limited to this configuration, the illumination system  20  (illumination unit  21 ) may also be configured to irradiate the wafer W with white light in a range including near-infrared light, and let a wavelength selection filter be appropriately inserted right in front of the imaging section  35  to only transmit the light (diffracted light) of the specific wavelength. 
         [0137]    Further, in each of the abovementioned embodiments, the wafer holder sucks and holds the wafer W. However, without being limited to this configuration, when it is not necessary to suck and hold the wafer W for example, then the wafer holder may also be configured to just support the wafer W. On such an occasion, moreover, a plurality of support portions  461  aligned approximately parallel to one another, as shown in  FIG. 16 , may be each formed into a pentahedron which is a triangle in a sectional view, to continuously support the wafer W from one end to the other end, and be arranged to extend along the incidence plane of the illumination light to the wafer W. 
         [0138]    Further, in each of the abovementioned embodiments, the explanations are made with an example of the inspection apparatus which includes an inspection section (the image processing section  41 ) to carry out inspection of the wafer W based on the detection signal (image signal) detected by the imaging section  35 . However, without being limited to this configuration, it is also possible to apply the present invention to any observation devices which observe the image of the wafer W acquired by the imaging section  35  without including such observation section. Further, in each of the abovementioned embodiments, the explanations are made with an example of the pattern A formed with the holes (or vias) which are arranged regularly. However, the inspection objects are not limited to this pattern, but may be any patterns having such a depth as formed from a surface of a substrate in an orthogonal direction to the surface. For example, without being limited to hole patterns, it is also possible to adopt line and space patterns. Further, in each of the abovementioned embodiments, concave mirrors are used as the illumination-side concave mirror  25  and light-receiving-side concave mirror  31 . However, without being limited to this configuration, it is also possible to replace the same with lenses. Further, while the light source is a built-in type in each of the abovementioned embodiments, it is also possible to use a fiber or the like to input light generated outside. 
         [0139]    Next, referring to the flowchart shown in  FIG. 17 , explanations will be given about a method for manufacturing a semiconductor device where the wafer W is inspected by the aforementioned inspection apparatus. The flowchart of  FIG. 17  shows a process for forming TSVs in the semiconductor device of a three-dimensional lamination type. In this TSV formation process, first, a resist is coated to the surface of a wafer (a bare wafer or the like) (step S 201 ). In this resist coating process, a resist coating device (not shown) is used, for example, to fix the wafer on a rotary support table with a vacuum chuck or the like, and rotate the wafer at a high speed to form a thin resist film after dropping liquid photoresist from a nozzle onto the surface of the wafer. 
         [0140]    Next, a predetermined pattern (a hole pattern) is exposed and projected to the wafer surface to which the resist has been coated (step S 202 ). In this exposure process, an exposure device is used, for example, to irradiate the resist on the wafer surface with a light beam of a predetermined wavelength (an energy beam such as an ultraviolet beam or the like) through a photomask formed with the predetermined pattern, so as to transfer the mask pattern to the wafer surface. 
         [0141]    Next, development is carried out (step S 203 ). In this development process, a developing device (not shown) is used, for example, to carry out a process for dissolving the resist in the exposed portion with a solvent, and preserving the resist pattern in the unexposed portion. By virtue of this, the hole pattern is formed with the resist on the wafer surface. 
         [0142]    Next, inspection is carried out on the wafer surface formed with the resist pattern (hole pattern) (step S 204 ). In the inspection process after development, a surface inspection apparatus (not shown) is used, for example, to irradiate the entire wafer surface with illumination light, take an image of the wafer with the diffracted light arising from the resist pattern, and inspect whether or not there is any abnormity in the resist pattern and the like from the image taken from the wafer. This inspection process determines whether or not the resist pattern is nondefective. When the resist pattern is defective, then it is determined whether or not to rework the wafer, i.e., to take an action of removing the resist and treating the wafer over again from the resist coating process. When detecting some abnormity (defection) for which the rework is needed, the resist is removed (step S 205 ) and the process from step S 201  to step S 203  is carried out over again. Further, the inspection result from the surface inspection apparatus is fed back to the resist coating device, the exposure device, and the developing device, respectively. 
         [0143]    When it is confirmed that no abnormity is present in the inspection process after development, then etching is carried out (step S 206 ). In this etching process, an etching device (not shown) is used, for example, to mask the preserved resist and remove the silicon part of the bare-wafer base to form the holes for TSV formation. By virtue of this, the repetitive pattern A, which is constituted by the holes for TSV formation, is formed in the surface of the wafer W. 
         [0144]    Next, inspection is carried out on the wafer W with the pattern A formed by etching (step S 207 ). The inspection process after etching is carried out by the inspection apparatus according to any of the aforementioned embodiments. In this inspection process, when some abnormity is detected, then according to the type and degree of the abnormity including the depth of the detected abnormity, it is determined to adjust which of the exposure conditions for the exposure device (deformation illumination condition, focus offset condition and the like) and/or which part of the etching device, whether or not to discard the wafer W, and/or whether or not to require a detailed analysis such as further breaking the wafer W to observe its cross section. When a serious and extensive abnormity is discovered in the wafer W after etching, then the wafer W cannot be reworked, and thus should be either discarded or diverted to analysis such as cross section observation and the like (step S 208 ). 
         [0145]    When it is confirmed that no abnormity is present in the inspection process after etching, then an insulation film is formed on the sidewall of each hole (step S 209 ), and the portion of each hole formed with the insulation film is filled with a conductive material such as Cu or the like (step S 210 ). By virtue of this, TSVs are formed in the wafer (bare wafer). 
         [0146]    Further, the inspection result from the inspection process after etching is fed back primarily to the exposure device and the etching device. When some abnormity has been detected in the cross-sectional shape of the holes and/or in the diameter of the holes, then the feedback is carried out to provide information for focus and/or dose adjustment of the exposure device, while when there is some abnormity in the hole shape in the depth direction and/or in the hole depth, then the feedback is carried out to provide information for adjusting the etching device. In the etching process for TSV formation, because it is necessary to form the holes with a high aspect ratio (depth/diameter) (such as 10 to 20), which is technically difficult, it is important to carry out those adjustments based on the feedbacks. In this manner, in the etching process, it is required to form deep holes at a nearly vertical angle and, in recent years, a method called RIE (Reactive Ion Etching) is widely adopted. In the case of inspection after etching, it is monitored whether or not there is any abnormity in the etching device. When some abnormity is detected, then such a feedback operation is mainly carried out as to shut down the etching device and adjust the same. As the parameters for adjusting the etching device, for example, the following ones are conceivable: the parameter for controlling the etching rate ratio between the vertical and horizontal directions, the parameter for controlling the depth, the parameter for controlling the uniformity within the wafer surface, and the like. 
         [0147]    Further, when the inspection process after development is carried out, then any abnormity in the resist application device, exposure device or developing device is basically detected in the inspection process after development. However, when the inspection process after development is not carried out, or if any problem in those devices is discovered for the first time through the etching, then feedback to each device (adjustment of each device) is carried out. 
         [0148]    On the other hand, it is also possible to feed forward the inspection result from the inspection process after etching to the succeeding processes. For example, when some chips of the wafer W are determined to be abnormal (defective) in the inspection process after etching, then that information is transmitted online from the aforementioned inspection apparatus  1  to the host computer (not shown) in control of the process, and is stored there for use in management such as in the case of not using the abnormal part (chips) in the inspection and measurement of the succeeding processes, etc., or for application in the case of not carrying out unnecessary electrical test at the stage of final completion of the device, etc. Further, when the abnormal part has a large area according to the inspection result from the inspection process after etching, then it is possible to use the information to reduce the influence on the nondefective part, etc., by accordingly adjusting the parameter for forming the insulation film or for filling of Cu. 
         [0149]    According to the method for manufacturing the semiconductor device in accordance with the present embodiment, because the inspection apparatus according to the aforementioned embodiments is used to carry out the inspection process after etching, it is possible to carry out the inspection based on the image of the wafer W with little noise, thereby improving the inspection precision. Hence, it is possible to improve the efficiency of manufacturing the semiconductor device. 
         [0150]    Further, in the aforementioned TSV formation process, TSVs are formed at the initial stage before forming any elements on the wafer. However, without being limited to this sequence, the TSVs may also be formed either after forming the elements or in the course of forming the elements. Further, in such case, implanting ions, etc., in the process of forming the elements may result in decreasing the degree of transparency for infrared but does not lead to complete opaqueness. Therefore, considering the change in transparency, it is only necessary to select the wavelength and/or adjust the amount of illumination light. Further, even on a production line using such method, as a condition required for the line and for QC purpose, when TSVs are formed in a bare wafer and inspection is carried out, then it is possible to carry out the inspection without being affected by the decrease in transparency due to the ion implantation. 
       INDUSTRIAL APPLICABILITY 
       [0151]    It is possible to apply the present invention to the inspection apparatus which is used in the inspection process after etching for manufacturing a semiconductor device. By virtue of this, it is possible to improve the inspection precision of the inspection apparatus, thereby being able to improve the efficiency of manufacturing the semiconductor device. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Inspection apparatus 
           9  Tilt mechanism (rotary section) 
           10  Wafer holder (first embodiment) 
           11  Support portion ( 11   a  Support surface,  11   b  Lateral side,  11   c  Edge line) 
           12  Groove portion (separate portion) 
           13  Connection portion (pressure reduction auxiliary portion) 
           14  Suction hole 
           16  Relief portion 
           20  Illumination system (illumination section) 
           30  Light receiving system (detection section) 
           35  Imaging section (detection section) 
           40  Control section 
           41  Image processing section (inspection section) 
           50  Transport unit 
           51  First transport device 
           61  Second transport device 
           71  Third transport device 
           73  Wafer holding device 
           77  Holding member 
           80  Wafer holder (modification of first embodiment) 
           86  Relief portion 
           90  Wafer holder (modification of first embodiment) 
           91  Support portion ( 91   b  Lateral side) 
           92  Groove portion (separate portion) 
           101  Support portion ( 101   a  Support surface,  101   b  Lateral side) 
           102  Groove portion (separate portion) 
           104  Suction hole 
           200  Wafer holder (second embodiment) 
           211  Support portion 
           212  Groove portion ( 211   a  Support surface,  211   b  Lateral side,  211   c  Edge line) 
           216  Relief portion 
           250  Wafer holder (modification of second embodiment) 
           261  Support portion ( 261   a  Support surface,  261   b  Lateral side,  261   c  Edge line) 
           262  Separate portion 
           300  Wafer holder (third embodiment) 
           311  Support portion 
           312  Groove portion (separate portion) 
           313  Connection portion 
           314  Suction hole 
           400  Wafer holder (fourth embodiment) 
           411  Support portion 
           412  Separate portion 
           413  Connection portion 
           414  Suction hole 
           461  Support portion (modification) 
           500  Wafer holder (conventional example) 
         C Wafer carrier 
         W Wafer 
         A Pattern 
         Wc Chip 
         Ws Street 
         S 1  to S 3  Pressure reduction space 
         T 1  and T 2  Observation area