JP2010286457A - Surface inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface inspection apparatus having a less effect of a non-sensitive region and improved inspection accuracy. <P>SOLUTION: The surface inspection apparatus includes: a stage 10 supporting an inspection object; an illuminating part 20 emitting illumination light to a surface of a wafer W supported by the stage 10; an imaging optical system 30 forming an image of the illumination light reflected from the surface of the inspection object on a predetermined imaging surface and shifting an optical axis; an imaging member taking the image, provided with picture elements receiving the image formed on the imaging surface by the imaging optical system 30 and the non-sensitive region disposed around the picture elements and not receiving the image; and an image processing part 45 generating an image of the surface of the inspection object based on the image taken by the imaging member. While the imaging optical system 30 is shifting the optical axis from the surface of the wafer W so that a position of the image to be formed on the imaging surface of the imaging member 60 may be shifted by a predetermined length, the imaging member 60 takes the image a plurality of times, so that the image processing part 45 combines each picture element in a plurality of taken images to generate a composite image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a surface inspection apparatus for inspecting the surface of a substrate such as a semiconductor wafer in a semiconductor manufacturing process.

  As a surface inspection device as described above, the surface of the silicon wafer is irradiated with illumination light to image regular reflection light or diffracted light from the surface of the silicon wafer, and the quality of the pattern is judged from the luminance change in the imaging surface. A surface inspection apparatus to perform is known (for example, see Patent Document 1). In such a surface inspection apparatus, as the pitch of the repetitive pattern becomes finer, the wavelength of illumination light is shortened to the ultraviolet region in order to generate diffracted light. Therefore, the imaging member mounted on the camera that images diffracted light has a small aperture ratio and low light receiving efficiency.

  In order to increase the light receiving efficiency, it is desirable to make the opening of the light receiving portion of the imaging member as large as possible, but it is necessary to arrange peripheral circuits that realize functions such as reducing noise and transferring information. A dead area that does not contribute to light reception must be provided in the pixel of the imaging member. That is, as shown in FIG. 9, in the imaging member C, a portion where the effective area (opening) A for light reception and the insensitive area B are combined is an area occupied by one pixel. As shown in FIG. 10 (a), information on the image formed on the effective area A (image of the wafer W) can be acquired as image information (luminance data), but as shown in FIG. 10 (b), Information on an image formed in the insensitive area B cannot be acquired as image information (luminance data). For this reason, the insensitive area information is not included in the reproduced image.

  Therefore, in order to guide more light to the aperture (effective area) of the imaging member, a condensing unit such as a microlens or an inner lens is disposed on the imaging surface of many imaging members, thereby improving the aperture ratio. The dead area is reduced. However, in the case of an imaging member that captures short-wavelength light, the above-described microlens and inner lens are generally made of a material having excellent moldability and high transparency in the visible range, such as PMMA, so that short-wavelength light such as ultraviolet rays is absorbed. Therefore, these cannot be used. Therefore, the imaging member for short wavelengths has a small aperture ratio.

JP 2008-151663 A

  In a surface inspection apparatus that has to use an imaging member with a small aperture ratio in order to use short-wavelength light, the aperture ratio of the imaging member is small, so the insensitive area is wide, and information on the image formed on the imaging surface is missing. The area becomes large, and the reproducibility of the image is lowered, which is a cause of a decrease in inspection accuracy.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a surface inspection apparatus in which the influence of the insensitive area is reduced and the inspection accuracy is improved.

  In order to achieve such an object, a surface inspection apparatus according to the present invention includes a stage that supports a test object, an illumination optical system that irradiates illumination light onto the surface of the test object supported by the stage, and An imaging optical system that forms an image of light reflected and emitted from the surface of the object irradiated with illumination light, and an imaging surface that is disposed at an imaging position by the imaging optical system, An imaging member that captures an image formed, and an image processing unit that generates an image of the surface of the test object based on the image captured by the imaging member, wherein the imaging surface of the imaging member In the surface inspection apparatus including a light receiving unit that receives the imaged image and a non-sensitive unit that is provided around the light receiving unit and does not receive the image, the imaging optical system includes the image Is shifted in the direction perpendicular to the optical axis. An optical path changing unit that changes an optical path of light emitted from the surface of the test object, and the image processing unit performs the optical path change by the optical path changing unit and the imaging by the imaging member a plurality of times. After the repetition, a plurality of images obtained by the repeated imaging are combined to generate a combined image.

  In the surface inspection apparatus described above, it is preferable that the imaging optical system shifts the image by 1 / n of an interval between adjacent pixels with respect to the imaging surface. However, n is an integer greater than 1.

  Further, in the above-described surface inspection apparatus, the imaging member outputs an image signal from the formed image to perform imaging, and the image processing unit includes a plurality of images obtained by the imaging repeated a plurality of times. It is preferable that the composite image is generated by combining the image signal of the image so that the pixel data does not overlap each other.

  In the surface inspection apparatus described above, the optical path changing unit is supported to be tiltable with respect to the light emitted from the test object, and a concave reflecting surface is directed toward the light and the light is reflected by the reflecting surface. It is preferable to change the optical path by tilting the concave mirror.

  Further, in the above-described surface inspection apparatus, the optical path changing unit is supported to be tiltable about an axis extending in a direction parallel to a plane perpendicular to a traveling direction of light emitted from the test object. A parallel plane plate having a transmission surface that transmits the light, and the optical path may be changed by tilting the parallel plane plate about the axis.

  In the surface inspection apparatus described above, the optical path changing unit is supported rotatably about an axis extending in a direction parallel to the traveling direction of the light emitted from the test object, and transmits the light. A declination prism having a transmission surface, the transmission surface being inclined with respect to a plane perpendicular to the optical axis, and the optical path by rotating the declination prism about the axis May be changed.

  In the surface inspection apparatus described above, the optical path changing unit is supported to be tiltable about an axis extending in a direction parallel to a plane perpendicular to the traveling direction of the light emitted from the test object. An objective lens that transmits the light and condenses it on the imaging surface of the imaging member, and the optical path may be changed by tilting the objective lens about the axis.

  According to the present invention, inspection accuracy can be improved.

It is a figure which shows the surface inspection apparatus of 1st Embodiment. It is a figure which shows the imaging device in 1st Embodiment (4th Embodiment). It is a schematic diagram which shows the detail of an imaging member. It is a schematic diagram which shows the example which the defect image imaged on the imaging member. It is a schematic diagram which shows the positional relationship of a defect image and an imaging member at the time of imaging while moving a defect image. It is a figure which shows the image process performed based on the result (The result of having performed the 1st-4th imaging) the image processing part imaged 4 times. It is a figure which shows the imaging device in 2nd Embodiment. It is a figure which shows the imaging device in 3rd Embodiment. It is a perspective view of the conventional imaging member. It is a figure which shows a mode that the image of a wafer forms an image.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A surface inspection apparatus 1 according to the present embodiment is shown in FIG. 1, and the surface of a semiconductor wafer (hereinafter referred to as a wafer W), which is a semiconductor substrate, is inspected by this apparatus. In the surface inspection apparatus 1 according to the present embodiment, the wafer W is transferred by a transfer apparatus (not shown) and placed on the stage 10 and fixed and held by vacuum suction by the stage 10 to inspect defects (abnormalities) on the surface. It is possible to do. The surface inspection apparatus 1 according to the first embodiment includes the above-described stage 10, the illumination optical system 20 that irradiates the surface of the wafer W with illumination light, and the regular reflection that is reflected from the surface of the wafer W after being irradiated with the illumination light. An imaging optical system 30 that photoelectrically converts an image of the surface of the wafer W with light to generate an image signal thereof, and an image processing unit 45 that generates an image of the surface of the wafer W by the image signal generated by the imaging optical system 30; It is comprised by. In the following description, the light traveling direction is defined as the positive Z-axis direction, the direction perpendicular thereto is defined as the X-axis direction, and the direction perpendicular to the Z-axis and the X-axis is defined as the Y-axis direction.

  The illumination optical system 20 includes an illumination unit 21 that emits illumination light, and an illumination-side concave mirror 25 that reflects the illumination light emitted from the illumination unit 21 toward the surface of the wafer W. The lighting unit 21 includes a light source unit 22 such as a metal halide lamp or a mercury lamp, a light control unit 23 that can extract light of a wavelength in a specific region from the light from the light source unit 22, and can adjust the intensity of the light. The light guide fiber 24 guides the light to the illumination-side concave mirror 25 as illumination light. The light emitted from the light source unit 22 is emitted from the light guide fiber 24 to the illumination side concave mirror 25 as illumination light having a specific wavelength (for example, 248 nm) by the light control unit 23. The light guide fiber 24 is arranged so that the emitted illumination light is positioned on the focal plane of the illumination-side concave mirror 25, and the illumination light is converted into a parallel beam by the illumination-side concave mirror 25 and held on the stage 10. Irradiate the surface.

  The imaging optical system 30 includes a light receiving side concave mirror 31 disposed to face the stage 10 and an imaging device 50 that captures an image of the wafer W. The emitted light (regular reflected light) is obtained by irradiating the illumination light onto the wafer W of the illumination optical system 20, and the emitted light (regular reflected light) is condensed and reflected by the light receiving side concave mirror 31 to be imaged. Is incident on. As shown in FIG. 2, the imaging device 50 includes an imaging lens group 51 including an objective lens that collects incident regular reflection light onto an imaging member 60 described later, and an imaging member 60 that forms an imaging surface. It is comprised. When regular reflection light from the surface of the wafer W reflected by the light-receiving-side concave mirror 31 enters the imaging device 50, it is condensed after passing through the imaging lens group 51 and forms an image on the imaging surface of the imaging member 60. It has become. The imaging member 60 photoelectrically converts the image of the wafer W formed on the imaging surface to generate an image signal, and outputs the image signal to the image processing unit 45 (detailed later).

  The image processing unit 45 generates an image of the wafer W based on the image signal input from the imaging member 60. The image processing unit 45 has an internal memory (not shown), and image data of non-defective wafers is stored in the internal memory in advance. After generating the image of the wafer W, the image processing unit 45 compares the image data with the image data of the non-defective wafer, and inspects whether there is a defect (abnormality) on the surface of the wafer W. The inspection result by the image processing unit 45 and the image (composite image) of the wafer W at that time are output and displayed on an image display device (not shown).

  The imaging member 60 is composed of, for example, a solid-state imaging device such as a CCD or a CMOS, and the imaging surface of the imaging member 60 is formed by gathering pixel regions 61 shown in FIG. The pixel region 61 includes a light receiving region 61a (also referred to as an opening or an effective region) that receives an image formed and a dead region 61b to 61d that does not receive the image. Hereinafter, the positional relationship between the image of the wafer W formed on the imaging surface of the imaging member 60 and the imaging member 60 will be described with reference to FIG. FIG. 3A schematically shows the imaging member 60, and FIG. 3B shows a light receiving area 61a and insensitive areas 61b, 61c, 61d in each pixel area 61 of the imaging member 60. FIG. ing. An interval between pixel centers in adjacent pixel regions 61 is referred to as a pixel interval. In the following, for convenience of explanation, as shown in FIG. 3, the lower right area of the pixel area 61 is a light receiving area 61a, and the lower left area, the upper left area, and the upper right area are insensitive areas 61b and 61c, respectively. , 61d will be described.

  First, an example in which a defect image on the wafer W is formed on the imaging surface of the imaging member 60 will be described with reference to FIG. In FIG. 4, the defect image 70 of the wafer W is imaged from the second pixel region 61 from the seventh surface from the left on the imaging surface of the imaging member 60 to the third pixel region 61 from the second from the left to the third. It is a figure which shows the state which carried out. In the case of the example shown in FIG. 4A, since the defect image 70 is in the sixth light receiving region 61a from the top left and the third light receiving region 61a from the top second from the left, the pixel region 61 is Although an image signal of the defect image 70 is generated, no image signal is generated because the other part is not in the light receiving region 61a. Therefore, the image signal is only at both end portions of the defect image 70 (black pixel region 61 shown in FIG. 4B), that is, the second from the second from the left, the second from the top from the left, the second 2 from the top. An image signal is output from only the pixel regions 61, and the image processing unit 45 receives the image signal, and as a final image, a defect image 70 such as a black portion in FIG. An image having a shape different from the shape is generated.

  Therefore, in the present invention, the position of the light impinging on the imaging surface of the imaging member 60 is set in the XY direction (relative to the traveling direction of the light) so that the image of the wafer W is formed at a position shifted by ½ of the pixel interval. It is possible to improve inspection accuracy by capturing a plurality of images while shifting in the vertical direction) and generating a composite image of the captured images. Hereinafter, four embodiments for shifting the position of the light will be described. First, in the first embodiment, as shown in FIG. 1, a mirror tilting device 80 capable of tilting the light-receiving-side concave mirror 31 about the X axis and the Y axis passing through the center is provided. Thus, a plurality of images of the wafer W are picked up by tilting the light-receiving side concave mirror 31 and shifting the position of light hitting the image pickup surface by ½ of the pixel interval.

  5A shows the positional relationship between the defect image 70 formed on the imaging surface of the imaging member 60 and the pixel region 61. FIG. 5B shows the light receiving side concave mirror 31 tilted by the mirror tilting device 80. FIG. FIG. 5C shows the positional relationship between the defect image 70 and the pixel region 61 that are shifted to the right by ½ of the pixel interval, and FIG. 5C shows the defect image that is shifted to the right and downward by ½ of the pixel interval. FIG. 5D shows the positional relationship between the defect image 70 and the pixel region 61 shifted downward by ½ of the pixel interval. As shown in FIGS. 5A to 5D, the mirror tilting device 80 tilts the light-receiving side concave mirror 31 and images the wafer W while shifting the image by a half of the pixel interval. The insensitive areas 61b to 61d of the imaging member 60 are complemented to each other by the image processing unit 45 generating these composite images (detailed later).

  In the following description, the imaging of the image formed as shown in FIG. 5A is shifted to the right by ½ of the first imaging and the pixel interval, and the imaging is performed as shown in FIG. 5B. The second image is taken, and the image taken as shown in FIG. 5C is shifted to the right and down by 1/2 of the pixel interval. The third image is taken by 1/2 of the pixel interval. Imaging of an image that is shifted downward and imaged as shown in FIG. 5D is referred to as fourth imaging.

  As described above, a method of capturing an image of the wafer W while shifting the image and generating a composite image by the image processing unit 45 will be described below with reference to FIGS. 5 and 6. First, when the first imaging is performed, an image signal of a black portion in FIG. 5A is output to the image processing unit 45. That is, in the case of the pixel region 61 shown in FIG. 5A, the image signal (referred to as image signal a) in the third pixel region 61 from the second top from the left and the second pixel region from the top six from the left. Only the image signal at 61 (referred to as image signal b) is output to the image processing unit 45.

  Further, as shown in FIG. 5B, when the second imaging is performed by tilting the light-receiving side concave mirror 31 by the mirror tilting device 80 and moving it to the right by ½ of the pixel interval, the second top from the left , Third from the left, third from the top, sixth from the left, second from the top, and seventh from the left, the second pixel region 61 (referred to as image signals c, d, e, and f, respectively). ) Is output to the image processing unit 45. Then, as shown in FIG. 5C, the light receiving side concave mirror 31 is tilted by the mirror tilting device 80 and moved downward from the state shown in FIG. The third to third pixel regions from the left, the fourth from the left to the third from the top, the fifth from the left to the third from the top, and the sixth to the third from the left. g, h, i, j) are output to the image processing unit 45. Further, as shown in FIG. 5D, the light-receiving-side concave mirror 31 is tilted by the mirror tilting device 80 and is moved leftward from the state shown in FIG. The third from the left, the third from the left, the third from the top, the fourth from the left, the third from the top, the fifth from the left, the third from the top, the sixth from the left, the third from the top Image signals in the region 61 (respectively image signals k, l, m, n, and o) are output to the image processing unit 45.

  The image processing unit 45 generates a composite image by associating the image signals a to o output by the above four imaging operations with the regions a to o. A method for generating a composite image will be described below with reference to FIG. FIG. 6 shows an image obtained by combining image signals output as a result of performing the first to fourth imaging. First, the number of pixels of the composite image generated by the image processing unit 45 is four times the number of pixels at the time of imaging. When four pixels are defined as one block in the composite image, the image signal obtained by the first imaging is The image signal obtained by the second imaging in which the image is shifted to the right by 1/2 the pixel interval at the lower right of the block is the lower left of the block, and the image after the second imaging is lower by 1/2 of the pixel interval The image signal obtained by the shifted third imaging is the upper left of the block, and the image signal obtained by the fourth imaging in which the image after the third imaging is shifted to the left by ½ of the pixel interval is on the upper right of the block. It corresponds.

  Specifically, the image signal a in the third pixel region 61 from the second top to the left of the first imaging and the image signal b in the second pixel region 61 from the top to the second from the left are the second top from the left. Are arranged in the lower right regions a and b of the third and sixth blocks from the left (see FIG. 6A). As described above, the image signals c to f output in the second imaging are the lower left of the corresponding block, the image signals g to j output in the third imaging are the upper left of the corresponding block, and the image output in the fourth imaging. The signals k to o are arranged at the upper right of the corresponding block. As a result, the defect image 70 image signal is output to the areas a to o in FIG. 6A, and the image processing unit 45 generates a composite image as shown by a set of minute points in FIG. 6B. In the above description, an example has been described in which images are captured while being shifted by a half of the pixel interval, and the image processing unit 45 generates a composite image that is four times the number of pixels at the time of imaging. When the image is taken while being shifted by 1 / n of the interval, a composite image that is n × n times the number of pixels is generated. Note that n is an integer greater than 1.

  As described above, according to the surface inspection apparatus 1 of the first embodiment, the light-receiving-side concave mirror 31 is tilted by the mirror tilting device 80, and the image processing unit 45 performs imaging a plurality of times while shifting the light hitting the imaging surface of the imaging member 60. Generates a composite image of the wafer W and performs surface inspection of the wafer W, so that it is possible to obtain image signals of images that could not be obtained by forming images on the insensitive areas 61b to 61d. By reproducing the image as a composite image, it is possible to reduce the influence of the insensitive area and improve the inspection accuracy.

  Next, a second embodiment of the surface inspection apparatus will be described with reference to FIG. The surface inspection apparatus according to the second embodiment is different from the surface inspection apparatus 1 according to the first embodiment only in the configuration of the imaging apparatus, and the other configurations are the same. Detailed description will be omitted. As shown in FIG. 7, the imaging device 90 according to the second embodiment includes an imaging lens group 51, a plane parallel plate 91, and a plane plate tilting device 92. The specularly reflected light emitted from the surface of the wafer W and collected by the light-receiving side concave mirror 31 passes through the imaging lens group 51 and is collected, and then enters the parallel flat plate 91.

  As shown in FIG. 7, the plane parallel plate 91 passes through the center of the plane parallel plate 91 and extends in the direction perpendicular to the light traveling direction (optical axis direction) by the plane plate tilting device 92. The specularly reflected light collected by the imaging lens group 51 is configured to be tiltable about two axes of a traveling direction (optical axis direction) and a Y axis perpendicular to the X axis. Is adjusted by the plane plate tilting device 92, whereby the position of the image formed on the imaging surface of the imaging member 60 can be changed. Specifically, when the plane parallel plate 91 is tilted about the Y axis, the optical axis is shifted in the X axis direction, and when tilted about the X axis, it is shifted in the Y axis direction. For example, a disk-shaped plate having a diameter of about 15 mm and a thickness of about 1 mm can be used as the plane-parallel plate 91 as described above. If the plane-parallel plate 91 is tilted once, the result is as follows. The position of the image to be imaged can be shifted by about 5 μm.

  A procedure for capturing an image of the wafer W formed on the imaging surface of the imaging member 60 using the surface inspection apparatus according to the second embodiment as described above and causing the image processing unit 45 to generate a composite image will be described. First, the first imaging is performed without tilting the plane parallel plate 91. Further, the parallel plate 91 is tilted about the Y axis so that the image of the wafer W is shifted in the X axis positive direction (right direction) by 1/2 of the pixel interval by the plane plate tilting device 92 to perform the second imaging. . Then, the third imaging is performed by tilting the plane-parallel plate 91 about the X axis so that the wafer image is shifted in the Y axis negative direction (downward) by 1/2 of the pixel interval. Further, the fourth imaging is performed by tilting the plane parallel plate 91 about the Y axis so that the image of the wafer W is shifted in the X axis negative direction (left direction) by 1/2 of the pixel interval. Thereafter, as in the first embodiment, the image processing unit 45 generates a composite image and inspects whether there is a defect (abnormality) on the surface of the wafer W, and the inspection result and the image of the wafer W (composite image). ) Is output and displayed on an image display device (not shown).

  As described above, in the surface inspection apparatus according to the second embodiment, the plane-plate tilting device 92 tilts the parallel plane plate 91 provided between the imaging lens group 51 and the imaging member 60 and hits the imaging surface of the imaging member 60. Since the image processing unit 45 generates a composite image of the wafer W and inspects the surface of the wafer W by shifting the light a plurality of times and performs the surface inspection of the wafer W, the influence of the insensitive area is reduced and the inspection accuracy is improved as in the first embodiment. Can be improved. In the second embodiment, an example in which one parallel plane plate 91 is tilted about the X axis and the Y axis by the plane plate tilting device 92 is described. However, the present invention is not limited to this configuration. Two parallel plane plates that tilt about the axis and two parallel plane plates that tilt about the Y axis may be provided to tilt each of the parallel plane plates.

  Next, a third embodiment of the surface inspection apparatus will be described with reference to FIG. The surface inspection apparatus according to the third embodiment is different from the surface inspection apparatus according to the second embodiment only in the configuration of the imaging apparatus, and the other configurations are the same. Detailed description will be omitted. As illustrated in FIG. 8A, the imaging device 100 according to the third embodiment includes an imaging lens group 51, a declination prism 101, and a prism rotation device 105. The specularly reflected light emitted from the surface of the wafer W and condensed by the light-receiving-side concave mirror 31 passes through the imaging lens group 51 and then enters the declination prism 101.

  As shown in FIG. 8, the declination prism 101 includes a first prism piece 102 and a second prism piece 103, and the first prism piece 102 is supported by the second prism piece 103 and is a prism rotation device. 105 is provided so as to be rotatable about a Z axis passing through the center of the first prism piece 102 and parallel to the light traveling direction. The light condensed by the imaging lens group 51 can change the position of the image formed on the imaging surface of the imaging member 60 by adjusting the rotation angle for rotating the first prism piece 102. It has become. Specifically, when the first prism piece 102 is rotated and the apex angle 102a of the first prism piece 102 is located on the X-axis negative direction side with respect to the Z-axis, the solid arrow in FIG. Thus, when the optical axis is shifted in the negative X-axis direction and the apex angle 102a is located on the positive X-axis side with respect to the Z-axis, the positive X-axis direction is indicated by the dotted arrow in FIG. It is supposed to shift to. Similarly, when the apex angle 102a is located on the Y axis positive direction side from the Z axis, the light of the specularly reflected light in the Y axis positive direction, and when the apex angle 102a is located on the Y axis negative direction side, the light of the specularly reflected light. It is possible to shift the position of the shaft. As the declination prism 101 as described above, for example, a prism having a diameter of about 25 mm and a thickness of about 2 mm can be used.

  A procedure for causing the image processing unit 45 to generate a composite image using the surface inspection apparatus according to the third embodiment configured as described above will be described below. First, first imaging is performed, and second imaging is performed by rotating the first prism piece 102 by 90 degrees in the clockwise direction on the imaging surface of the imaging member 60 by the prism rotating device 105. Then, the third imaging is performed by rotating again 90 degrees in the clockwise direction, and the fourth imaging is performed by rotating 90 degrees in the clockwise direction again. Thereafter, as in the first and second embodiments, the image processing unit 45 generates a composite image and performs a defect inspection of the wafer W, and the result is displayed on an image display device (not shown).

  As described above, according to the surface inspection apparatus in the third embodiment, the wafer is rotated a plurality of times while rotating the first prism piece 102 so that the image formed on the imaging surface of the imaging member 60 is shifted by ½ of the pixel interval. When W is imaged and the image processing unit 45 generates the composite image, the inspection accuracy can be improved as in the first and second embodiments. In addition, unlike the second embodiment, the plane-parallel plate 91 is not tilted about the two axes of the X axis and the Y axis, but the declination prism 101 only needs to be rotated about the Z axis. The mechanism of the inspection apparatus can be simplified. In addition, although the example which rotates the 1st prism piece 102 with respect to the 2nd prism piece was demonstrated above, the same effect can be acquired even if it rotates the 1st and 2nd prism pieces 102 and 103 together. it can.

  A fourth embodiment of the surface inspection apparatus will be described. As shown in FIG. 2, the imaging device 120 in the fourth embodiment is configured in the same manner as the imaging device 50 in the first embodiment, but an objective lens (not shown) of the imaging lens group 121 passes through the center thereof. In addition, the X-axis extending in a direction perpendicular to the light traveling direction and the Y-axis perpendicular to the light traveling direction and the X axis are supported so as to be tiltable with respect to the first to third embodiments. Different. The objective lens according to the fourth embodiment can be tilted about the X axis and the Y axis by a lens tilting device (not shown), similarly to the plane parallel plate 91 according to the second embodiment. Thus, the position of the optical axis of the light impinging on the imaging surface of the imaging member 60 can be shifted.

  A procedure for causing the image processing unit 45 to generate a composite image using the surface inspection apparatus according to the fourth embodiment as described above will be described below. First, the first imaging is performed without tilting the objective lens. Further, the second imaging is performed by tilting the objective lens so that the image of the wafer W is shifted by the lens tilting device in the positive X-axis direction (right direction) by 1/2 of the pixel interval. Then, the objective lens is tilted so as to be shifted in the Y-axis negative direction (downward) by 1/2 of the pixel interval, and the third imaging is performed, and further, the X-axis negative direction (leftward) is set by 1/2 of the pixel interval. The fourth lens is picked up by tilting the objective lens so as to deviate. Thereafter, as in the first to third embodiments, the image processing unit 45 generates a composite image and performs a defect inspection of the wafer W, and displays the result on an image display device (not shown).

  As described above, according to the surface inspection apparatus in the fourth embodiment, the objective lens is tilted, and the image processing unit 45 performs imaging a plurality of times while shifting the position of the optical axis of the light hitting the imaging surface of the imaging member 60. By generating the composite image, the inspection accuracy can be improved as in the first to third embodiments.

  As described above, in each of the above-described embodiments, an example of capturing a plurality of images while shifting the position of the optical axis so that the image of the wafer W is formed by being shifted by ½ of the pixel interval of the imaging member 60. As described above, the length of shifting the optical axis is not limited to 1/2 of the pixel interval, and may be 1 / n of the pixel region 61, for example. However, n is an integer greater than 1.

  In each of the above-described embodiments, the example using the specularly reflected light from the wafer W has been described. However, the present invention is not limited to this example. For example, the wafer is tilted by a tilting mechanism (not shown) and diffracted light of a specific order. The present invention can also be applied to the case where the light is used or the scattered light generated on the surface of the wafer W is used.

  In each of the above-described embodiments, the surface inspection apparatus that inspects the surface of the wafer W is shown. However, the present invention is not limited to this. For example, the present invention is applied to a surface inspection apparatus that inspects the surface of a glass substrate. be able to.

W wafer 1 Surface inspection device (first embodiment)
10 Stage 20 Illumination Optical System 30 Imaging Optical System 31 Receiving Side Concave Mirror (Concave Mirror)
45 Image processing unit 60 Imaging member 61 Pixel region 61a Light receiving region (light receiving unit)
61b Insensitive area (insensitive area) 61c Insensitive area (insensitive area)
61d Insensitive area (insensitive area) 91 Parallel plane plate 101 Deflection prism

Claims (7)

A stage that supports the specimen;
An illumination optical system for irradiating illumination light onto the surface of the test object supported by the stage;
An imaging optical system that forms an image of light reflected and emitted from the surface of the object irradiated with the illumination light;
An imaging member that is arranged so that an imaging surface is positioned at an imaging position by the imaging optical system, and that images the imaged image;
An image processing unit that generates an image of the surface of the test object based on an image captured by the imaging member;
In the surface inspection apparatus having a pixel in which the imaging surface of the imaging member includes a light receiving unit that receives the formed image and a non-sensitive unit that is provided around the light receiving unit and does not receive the image,
The imaging optical system includes an optical path changing unit that changes an optical path of light emitted from the surface of the test object so that the image is shifted in a direction orthogonal to the optical axis.
The image processing unit repeats the change of the optical path by the optical path changing unit and the imaging by the imaging member a plurality of times, and then combines a plurality of images obtained by the imaging repeated the plurality of times to obtain a composite image. A surface inspection apparatus characterized by generating. The surface inspection apparatus according to claim 1, wherein the imaging optical system shifts the image by 1 / n of an interval between adjacent pixels with respect to the imaging surface.
However, n is an integer greater than 1. The imaging member outputs an image signal from the imaged image to perform imaging,
The image processing unit generates the composite image by combining image signals of a plurality of images obtained by the imaging repeated a plurality of times so that the pixel data does not overlap each other. Item 3. The surface inspection apparatus according to Item 1 or 2. The optical path changing unit is a concave mirror that is supported so as to be tiltable with respect to the light emitted from the test object, directs a concave reflective surface to the light, and reflects the light by the reflective surface,
The surface inspection apparatus according to claim 1, wherein the optical path is changed by tilting the concave mirror. The optical path changing unit is supported to be tiltable about an axis extending in a direction parallel to a plane perpendicular to a traveling direction of light emitted from the test object, and a transmission surface that transmits the light. A plane parallel plate having
The surface inspection apparatus according to claim 1, wherein the optical path is changed by tilting the parallel plane plate about the axis. The optical path changing unit is rotatably supported around an axis extending in a direction parallel to the traveling direction of the light emitted from the test object, and has a transmission surface that transmits the light. A declination prism provided to be inclined with respect to a plane perpendicular to the axis;
The surface inspection apparatus according to claim 1, wherein the optical path is changed by rotating the declination prism about the axis. The optical path changing unit is supported to be tiltable about an axis extending in a direction parallel to a plane perpendicular to a traveling direction of light emitted from the test object, and transmits the light to perform the imaging. An objective lens that focuses light on the imaging surface of the member,
The surface inspection apparatus according to claim 1, wherein the optical path is changed by tilting the objective lens about the axis.

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