JP2009020021A - Apparatus and method for inspecting end of inspecting object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently inspect the condition of an end of an inspecting object, and to easily acquire an image of a defective part occurring in the inspection object. <P>SOLUTION: This end inspection apparatus inspects the condition of the end of the inspecting object by imaging the end of the inspecting object while rotating the disk-like inspecting object having a thin film. The surface of the inspecting object is formed of a flat part and an inclined part that is disposed at the rim of the flat part and is inclined down towards the circumferential surface of the inspecting object. The end inspection apparatus comprises: a first image acquiring means for acquiring the image of the end of the inspecting object including a part of the inclined part and the flat part; and an image comparing means for recognizing whether the thin film is formed in the inclined part by comparing a basic image showing the end of the surface of the inspecting object having no thin film with the image acquired by the first image acquiring means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an end inspection apparatus for inspecting an end of an object to be inspected such as a semiconductor wafer, and an end inspection method for the inspected object.

  In recent years, the degree of integration of circuit patterns formed on semiconductor wafers has been increasing year by year, and the types of substances used for wafer surface treatment during production have increased. Along with this, observation of the vicinity of the edge of the wafer located at the boundary of the film formed on the wafer in the production process has become important. This defect management near the end face affects the yield of circuits made from the wafer.

For this reason, in addition to observing the periphery of the edge of a semiconductor wafer or the like from a plurality of directions to inspect the state of the edge of the semiconductor wafer, the edge of the semiconductor wafer is irradiated with laser light around the edge of the semiconductor wafer. Receiving specular reflection light and scattered reflection light generated when reflected at the periphery, the state of the edge of the semiconductor wafer is inspected by detecting the presence or absence of scratches and calculating the surface roughness based on the amount of light received. (For example, patent document 1).
JP-A-11-351850

  However, since the inspection of the state near the edge of the semiconductor wafer is performed over the entire circumference of the semiconductor wafer while repeating the rotation of the object to be inspected and the observation of the edge of the semiconductor wafer, the inspection of the semiconductor wafer is performed once. Since all the images obtained are referred to determine the presence or absence of defects at the edge of the semiconductor wafer, there is a problem that the edge of the semiconductor wafer cannot be efficiently inspected. In addition, when inspecting the state of the end of the object to be inspected based on the amount of received light of regular reflection light and scattered reflection light, it is possible to detect the presence or absence of a flaw and the type of flaw (vertical flaw, horizontal flaw, oblique flaw, etc.). In this case, since the flaw itself is not observed as an image, there is a problem that the generation range of the flaw cannot be observed.

  The present invention efficiently inspects the state of the end portion of an object to be inspected, and can easily acquire an image of a defective portion generated in the object to be inspected, and inspection of the object to be inspected It aims to provide a method.

  In order to solve the above-mentioned problem, the edge inspection apparatus of the present invention images the edge of the inspection object while rotating the disk-shaped inspection object on which a thin film is formed. In the end inspection apparatus for inspecting the state of the end of the test object, the surface of the object to be inspected is a flat part, and an inclined part that is located at the periphery of the flat part and inclines downward toward the peripheral surface of the object to be inspected. A first image acquisition unit configured to acquire an image of an end portion of the inspection object including a part of the inclined portion and the flat portion from above the inspection object; and the thin film is formed. Whether or not the thin film is formed on the inclined portion by comparing a basic image showing an end portion of the surface of the object to be inspected and an image acquired by the first image acquisition means Recognizing image comparison means.

  In addition, the image processing apparatus includes a calculation unit that calculates a distance from a ridge line between the inclined portion and the peripheral surface to an outer edge portion of the thin film from an image acquired by the first image acquisition unit.

  Moreover, when the outer edge part of the said thin film cross | intersects with respect to the ridgeline of the said inclination part and the said surrounding surface, the 2nd which acquires the image of the surrounding surface of the to-be-inspected object in the location where the said thin film crossed A first image acquisition unit, a first image acquisition unit, and a second image acquisition unit obtain a correlation between the thin films on a peripheral surface from an inclined portion of the object to be inspected. And a state acquisition means.

  Further, when the outer edge of the thin film intersects the ridgeline between the peripheral surface of the object to be inspected and the back surface of the object to be inspected, the back surface end of the object to be inspected at the location where the thin film intersects Correlation of the thin film from the peripheral surface to the back surface of the object to be inspected from the images obtained by the third image obtaining means for obtaining the image of the part, the second image obtaining means, and the third image obtaining means. And second state acquisition means for acquiring a relationship.

  In this case, when it is determined from the correlation of the thin film that the boundary of the thin film is not continuous, using the first image acquisition means, the second image acquisition means, and the third image acquisition means, It is preferable to acquire an image of a peripheral portion of a region where the thin film is not continuous.

  Further, the range in which the defect has occurred is identified by a difference detection method using the defect acquired by the first image acquisition unit, the second image acquisition unit, and the third image acquisition unit and an image of the periphery thereof. It is preferable that a range specifying means is provided.

  In addition to specifying the range in which the defect has occurred, the range specifying unit can specify the diffusion direction of the defect, and based on the specified diffusion direction of the defect, the first image It is preferable to newly acquire a defect image using at least one of the acquisition unit, the second image acquisition unit, and the third image acquisition unit.

  The end inspection method of the object to be inspected according to the present invention is a method for inspecting the end of the inspected object by imaging the end of the inspected object while rotating the disk-shaped inspected object. The surface of the object to be inspected includes a part of the flat part and an inclined part that is located at the peripheral part of the flat part and is inclined downward toward the peripheral surface of the object to be inspected from above the object to be inspected By comparing the first step of acquiring an image at the edge of the first image, the basic image showing the edge of the surface of the object to be inspected on which the thin film is not formed, and the image acquired in the first step, And a second step of recognizing the presence or absence of the outer edge of the thin film in the inclined portion.

  According to the present invention, the state of the end of the object to be inspected can be efficiently inspected, and when a defect occurs in the thin film of the object to be inspected, an image of the defect can be efficiently acquired. .

  FIG. 1 is a schematic view showing a configuration of an end portion inspection apparatus 10 of the present invention. The edge inspection apparatus 10 includes a holding table 11, a rotation drive unit 12, a horizontal drive unit 13, and the like. The holding table 11 sucks and holds the semiconductor wafer 15 placed on the upper surface thereof. The rotation drive unit 12 rotates the holding table 11 by a predetermined angle. The predetermined angle is, for example, an angle that becomes a continuous image when images obtained at adjacent inspection positions are arranged, and this angle is set based on an imaging range in the CCD 29 described later.

  The horizontal drive unit 13 moves the holding table 11 and the rotation drive unit 12 in the horizontal direction. Here, the horizontal direction is a direction parallel to the surface of the holding table 11 on which the semiconductor wafer 15 is placed. By providing the horizontal driving unit 13, when the semiconductor wafer 15 is placed on the holding table 11, the center of the semiconductor wafer 15 and the rotation center of the holding table 11 can be matched, that is, the eccentric state can be corrected. it can.

  The edge inspection apparatus 10 includes a first image acquisition unit 21 that acquires an image of the upper surface of the end of the semiconductor wafer 15, a second image acquisition unit 22 that acquires an image of the peripheral surface of the semiconductor wafer 15, and the semiconductor wafer 15. And a third image acquisition unit 23 for acquiring an image of the lower surface of the end of the image.

  The first image acquisition unit 21 is disposed above the semiconductor wafer 15 sucked and held on the holding table 11. The first image acquisition unit 21 includes a light source 25, a lens 26, a half mirror 27, an imaging lens 28 and a CCD 29. As the light source 25, for example, a halogen lamp or LED is used. Light emitted from the light source 25 enters the half mirror 27 through the lens 26 and is reflected by the half mirror 27. The semiconductor wafer 15 is illuminated by the reflected light. Thereby, the semiconductor wafer 15 is illuminated by epi-illumination. Note that the upper end portion of the semiconductor wafer 15 illuminated by the epi-illumination is picked up by the CCD 29 disposed above it, that is, a bright field image is acquired.

  The second image acquisition unit 22 includes a light source 30, a lens 31, a half mirror 32, an imaging lens 33, and a CCD 34. The second image acquisition unit 22 is located on the side of the semiconductor wafer 15 sucked and held on the holding table 11, and the imaging optical axis L 2 of the CCD 34 is orthogonal to the imaging optical axis L 1 of the CCD 29 of the first image acquisition unit 21. Are arranged as follows.

  The third image acquisition unit 23 includes a light source 35, a lens 36, a half mirror 37, an imaging lens 38 and a CCD 39. The third image acquisition unit 23 is below the semiconductor wafer 15 sucked and held by the holding table 11, and the imaging optical axis L 3 of the CCD 39 is substantially coaxial with the imaging optical axis L 1 of the CCD 29 of the first image acquisition unit 21. Are arranged as follows. In addition, since the structure of the 2nd image acquisition part 22 and the 3rd image acquisition part 23 is the structure similar to the 1st image acquisition part 21, the detail in these image acquisition parts is abbreviate | omitted.

  FIG. 2 shows an image acquisition range for the semiconductor wafer 15. Specifically, FIG. 2A is a top view of the semiconductor wafer 15, and FIG. 2B is a cross-sectional view taken along the line C-C ′ in FIG. Since the first image acquisition unit 21 is located above the semiconductor wafer 15, when the semiconductor wafer 15 is viewed from above, the image acquisition range on the semiconductor wafer 15 by the first image acquisition unit 21 is the semiconductor wafer 15. This is the range indicated by the symbol A at the upper surface end of the. The range indicated by the symbol A includes an inclined surface (hereinafter referred to as an upper bevel) 15a formed at an upper end portion of the semiconductor wafer 15, a part of a flat surface 15b continuous with the upper bevel 15a, and the outer side of the semiconductor wafer 15. It is a range including.

  Since the second image acquisition unit 22 is disposed outside the side surface (hereinafter referred to as apex) 15c of the semiconductor wafer 15, the image acquisition range of the semiconductor wafer 15 by the second image acquisition unit 22 is the apex 15c. .

  As described above, the third image acquisition unit 23 is arranged so that the imaging optical axis L3 thereof is substantially coaxial with the imaging optical axis L1 of the first image acquisition unit 21. The image acquisition range of the semiconductor wafer 15 by 23 is substantially the same as the image acquisition range of the first image acquisition unit 21 and is the lower surface thereof, but the third image acquisition unit 23 is arranged below the semiconductor wafer 15. Therefore, the image acquisition range by the third image acquisition unit 15 is a range including the lower bevel 15d, a part of the flat surface 15e connected to the lower bevel 15d, and the outside of the semiconductor wafer 15.

  Returning to FIG. 1, the control device 45 operates the horizontal drive unit 13 to adjust the position of the holding table 11 in the horizontal direction, as well as the rotation drive unit 12, the first image acquisition unit 21, and the second image acquisition unit. 22, the operation of the third image acquisition unit 23 is controlled. The control device 45 includes an image comparison unit 50, a state acquisition unit 51, and a range specifying unit 52.

The image comparison unit 50 includes an image of the upper bevel 15a (hereinafter referred to as an inspection image) of the semiconductor wafer 15 on which the thin film 16 is formed, an inspection image of the apex 15c and the lower bevel 15d, and the semiconductor wafer 15 on which the thin film 16 is not formed. An image (hereinafter referred to as a basic image) is compared to identify the boundary of the thin film 16. In the following, the inspection image of the upper bevel 15a is represented by PU _n (n: n = 1 when obtained at a reference inspection position), the inspection image of the apex 15c is PA _n , and the inspection image of the lower bevel 15d. Will be referred to as PD _n , the basic image of the upper bevel 15a will be referred to as PU ₀ , the basic image of the apex 15c as PA ₀ , and the basic image of the lower bevel 15d as PD ₀ .

FIG. 3 shows a comparison procedure between the inspection image PU _n of the upper bevel 15 a of the semiconductor wafer 15 and the basic image PU ₀ . As a method of comparing the inspection image PU _n and the basic image PU ₀ , the pixel value of the pixel at the same position in the basic image PU ₀ is subtracted from the pixel value of each pixel of the inspection image PU _n . For example, since the pixel value of the pixel corresponding to the thin film 16 among the pixels of the inspection image PU _n is different from the pixel value of the pixel where the thin film 16 is not formed, the pixel corresponding to the location where the thin film 16 is formed And a pixel value of a pixel in which the thin film 16 is not formed.

On the other hand, the pixel value of the pixel corresponding to the portion where the thin film 16 is not formed is almost constant. For this reason, by comparing the inspection image PU _n and the basic image PU ₀ , the pixel region where the difference is larger than a certain threshold is specified as the region where the thin film 16 is formed. By this specification, the boundary of the thin film 16 formed on the semiconductor wafer 15 is specified. The same applies to the comparison between the inspection image PA _n of the apex 15a and the basic image PA _0, and the comparison between the inspection image PD _n of the lower bevel 15d and the basic image PD _0, and the details are omitted here.

The image comparison unit 50 includes a distance calculation unit 54. When the distance calculation unit 54 compares, for example, the inspection image PU _n of the upper bevel 15a and the basic image PU ₀ , the distance D from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 (See FIG. 3) is calculated. That is, the position in the Y direction with respect to the boundary B0 between the upper bevel 15a and apex 15c are recognized from the inspection image PU _n and basic image PU ₀ above bevel 15a, a thin film in comparison with the test image PU _n and the basic image PU ₀ 16 Since the region of the pixel in which no is formed is also specified, the number of pixels in which no difference occurs in the pixel value in the Y direction from the boundary B0 between the upper bevel 15a and the apex 15c is specified. Since the scale for one pixel is known in advance, the distance D from the boundary L0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 is calculated from the specified number of pixels and the scale.

The state acquisition unit 51 acquires the state of the boundary B1 of the thin film 16 from the result of comparing the inspection image PU _n and the basic image PU ₀ by the image comparison unit 50. For example, since the number of pixels (or distance) from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 is calculated by the image comparison unit 50, the number of images is compared in each of the X directions. As a result, the state of the thin film 16 formed on the upper bevel 15a of the semiconductor wafer 15 is acquired. For example, at each position in the X direction, when the distance D from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 is within the crossing range at the design stage, the thin film 16 is formed normally. Recognize that

As shown in FIG. 4, when there is a point where the number of pixels from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 is 0 at any position in the X direction, the thin film It is recognized that 16 boundaries B1 intersect the boundary B0 between the upper bevel 15a and the apex 15c. In this case, the inspection images PA _n Apex 15c is acquired by the second image acquisition unit 22.

Also in this case, the acquired inspection image PA _n of the apex 15c and the basic image PA ₀ are compared. Since this comparison is also similar to the comparison between the inspection image PA _n of the upper bevel 15a and the basic image PA ₀ , the details thereof are omitted, but the basic image PA ₀ corresponding to each pixel of the inspection image PA _n is determined by this comparison. A region of a pixel having a difference from each pixel larger than the threshold is specified as a region where the thin film 16 is formed, and a region of a pixel whose difference is smaller than the threshold is specified as a region where the thin film 16 is not formed.

Furthermore, when the number of pixels in the Z direction is 0 until the boundary B1 of the thin film 16 and the boundary B2 between the apex 15c and the lower bevel 15d, if the boundary of the thin film 16 formed on the apex 15c is B1 ′, determines a boundary B1 of the thin film 16 'crosses the boundary between the apex 15c and the lower bevel 15d, an inspection image PD _n of the lower bevel 15d is acquired by the third image acquisition unit 23. Again, compared with the inspection image PD _n and the basic image PD ₀ under bevel 15d obtained is performed. Comparison of flow and description of the inspection image PD _n and the basic image PD ₀ below bevel 15d thereof is omitted details.

When comparing the inspection image PU _n of the upper bevel 15a with the basic image PU ₀ , comparing the inspection image PA _n of the apex 15c with the basic image PA _0, and further comparing the inspection image PD _n and the basic image PD of the lower bevel 15d. At the time of comparison with ₀ , there may be a case where an area where the difference in pixel value is smaller than a threshold value changes suddenly in the outer peripheral direction (X direction). In this case, it is determined that the boundary of the thin film 16 is not continuous. When this determination is made, the control device 45 rotates forward and backward by a predetermined angle from the current inspection position via the rotation drive unit 12, and acquires inspection images of the upper bevel 15a, apex 15c, and lower bevel 15d, respectively. .

  The range specifying unit 52 determines an area (defect area) where a defect is generated from the inspection images of the upper bevel 15a, apex 15c, and lower bevel 15d acquired when it is determined that the boundary of the thin film 16 is not continuous. Identify. For example, a difference inspection method is used to specify the defect range. Since the difference inspection method is well known, the details thereof are omitted here. However, as shown in FIG. 5, all acquired inspection images are divided into a plurality of regions in the X direction, and adjacent regions are inspected. A difference between pixel values of images having the same position coordinate value in the Y direction is calculated. When this difference is calculated, a location where the difference is larger than the threshold (a region indicated by hatching in FIG. 5) is a location where a defect occurs, and a location where the difference is less than the threshold is a location where no defect occurs To do. By calculating this difference for all regions, in addition to the presence or absence of defects, the position and range of the defects, and the direction in which the defects extend (diffusion direction) can be specified. When the position and range of the generated defect are specified, an image of the entire defect is acquired using any of the first image acquisition unit 21, the second image acquisition unit 22, or the third image acquisition unit 23. The The acquired image of the entire defect is stored in the memory of the control device 45 together with the inspection position. In addition, even if the position of the defect can be specified but the range cannot be specified, the inspection position where the defect is detected is stored in the control device 45 and the end of the semiconductor wafer 15 is inspected over the entire circumference. Later, the semiconductor wafer 15 may be inspected again with another device.

  In addition, instead of dividing all acquired inspection images into a plurality of regions in the X direction, the above-described image determination unit 50 compares the inspection image with the basic image, and there is no continuity at the thin film boundary. After extracting the inspection image, it is also possible to specify the defect range by the above-described differential inspection method for the extracted inspection image.

  Next, the flow of inspection of a semiconductor wafer in the edge inspection apparatus 10 of the present invention will be described using the flowchart of the drawing.

Step S1 is a process of acquiring the basic images PU ₀ , PA ₀ , PD ₀ of the semiconductor wafer 15 on which the thin film 16 is not formed. In step S1, the semiconductor wafer 15 on which the thin film 16 is not formed is set on the holding table 11, and the first image acquisition unit 21, the second image acquisition unit 22, and the third image acquisition unit 23 are sequentially operated, The basic image PU ₀ of the upper bevel 15a, the basic image PA ₀ of the apex 15c, and the basic image PD ₀ of the lower bevel 15d are acquired. In step S1, when each basic image is acquired, the process of step S1 ends, and the process proceeds to step S2.

Step S2 is a process of acquiring the inspection image PU _n of the upper bevel 15a of the semiconductor wafer 15 on which the thin film 16 is formed. In step S <b> 2, the semiconductor wafer 15 on which the thin film 16 is not formed is removed from the holding table 11, and the semiconductor wafer 15 on which the thin film 16 is formed is set on the holding table 11. Thereafter, the inspection image PU ₁ of the upper bevel 15 a of the semiconductor wafer 15 at the reference position is acquired using the first image acquisition unit 21 with the state set on the holding table 11 as the reference position. When the inspection image of the upper bevel 15a is acquired, the process of step S2 ends, and the process proceeds to step S3.

Step S <b> 3 is a process of specifying the boundary of the thin film 16. In step S3, and the image comparing section 50 is operated, to compare the test image PU ₁ and the basic image PU ₀ acquired, identifying the boundaries B1 of the thin film in the upper bevel 15a 16. When the process of specifying the boundary B1 of the thin film 16 is performed, the process proceeds to step S4.

  Step S4 is a process of determining whether or not the specified boundary B1 of the thin film 16 intersects the boundary B0 between the upper bevel 15a and the apex 15c. In this determination, when it is determined that the boundary B1 of the thin film 16 intersects the boundary B0 between the upper bevel 15a and the apex 15c, the process proceeds to step S5, and when it is determined that the boundary does not intersect, Proceed to step S10.

Step S5 is a process of acquiring an inspection image PA ₁ of the apex 15c. In step S5, the second image acquisition unit 22 is activated, the inspection image PA ₁ Apex 15c is obtained. When this process ends, the process proceeds to step S6.

Step S6, and compares the inspection image PA ₁ and the basic image PA ₀ of the obtained apex 15c, a process for specifying the boundary B1 'of the thin film 16 formed on the apex 15c. When the process of specifying the boundary B1 ′ of the thin film 16 is performed, the process proceeds to step S7.

  Step S7 is a process of determining whether or not the boundary B1 'of the specified thin film 16 intersects the boundary B2 between the apex 15c and the lower bevel 15d. In this determination, when it is determined that the boundary B1 ′ of the thin film 16 intersects the boundary B2 between the apex 15c and the lower bevel 15d, the process proceeds to step S8, and when it is determined that the boundary does not intersect. The process proceeds to step S10.

Step S8 is processing for acquiring an inspection image of the lower bevel 15d. In step S8, the third image acquisition unit 23 is activated, the inspection image PD ₁ below bevel 15d is obtained. When this process ends, the process proceeds to step S9.

Step S9 carries out comparison between the inspection image PD ₁ and the basic image PD ₀ under bevel 15d obtained, a process for specifying the boundary of the thin film 16 formed on the lower bevel 15d. If the process which specifies the boundary of the thin film 16 is made, it will progress to step S10.

  Step S10 is a process of calculating a distance D from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16. That is, since the boundary B1 of the thin film 16 is specified in step S3, the actual distance D is calculated from the number of pixels from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film. When the process of calculating the distance D from the boundary B0 between the upper bevel 15a and the apex 15c to the boundary B1 of the thin film 16 is completed, the process proceeds to step S11.

  Step S11 is a process of determining whether or not the boundary B1 of the thin film 16 formed on the semiconductor wafer 15 is a boundary having continuity. If it is determined in step S11 that there is no continuity, the process proceeds to step S12. If it is determined that there is continuity, the process proceeds to step S14.

  Step S12 is processing for specifying a defective area. As described above, the flow for specifying the defective area is obtained by acquiring an inspection image when the holding table 11 on which the semiconductor wafer 15 is set is rotated forward or reverse by a predetermined angle from the current inspection position. This is a process for specifying a defect area, a direction in which the defect spreads, and the like from the inspection image thus obtained. When this process is executed, the process proceeds to step S13.

  Step S13 is a process for acquiring an image of the specified defective area. In step S13, based on the defect area specified in step S12, the first image acquisition unit 21, the second image acquisition unit 22, and the third image acquisition unit 23 are operated to acquire an image of the defect area. . When this process ends, the process proceeds to step S14.

  Step S <b> 14 is processing for determining whether or not inspection has been performed over the entire circumference of the semiconductor wafer 15. If it is determined in step S <b> 13 that the inspection has been performed over the entire circumference of the semiconductor wafer 15, the inspection of the semiconductor wafer 15 ends. On the other hand, if the inspection has not been performed over the entire circumference, the process proceeds to step S15, and the holding table is rotated by a predetermined angle. Thereafter, returning to step S2, the inspection of the end portion of the semiconductor wafer 15 at a different inspection position is executed according to the procedure described above.

According to this, as long as the inspection image PU _n of the upper bevel 15a is compared with the basic image PU ₀ , the formation state of the thin film 16 becomes normal, and it is specified that the boundary B1 of the thin film 16 has continuity. Since it is not necessary to acquire the inspection image PA _n of the apex 15c and the inspection image PD _n of the lower bevel 15d, the number of acquired inspection images can be reduced and the inspection images are compared. Since it is not necessary, the presence or absence of defects in the semiconductor wafer 16 can be detected efficiently.

Further, when the inspection image PU _n of the upper bevel 15a is compared with the basic image PU ₀ , the formation state of the thin film 16 becomes normal, and if it is specified that the boundary of the thin film 16 is continuous, the upper bevel By calculating the distance D from the boundary B0 between the boundary 15a and the apex 15c to the boundary B1 of the thin film 16, the formation state of the thin film 16 can be managed by grasping the formation state of the thin film 16 that is actually formed. It becomes possible.

  When the boundary B1 of the thin film 16 intersects the boundary B0 between the upper bevel 15a and the apex 15c, or when it intersects the boundary B2 between the apex 15c and the lower bevel 15d, the apex 15c and the lower bevel 15d Since an inspection image is acquired, an image of a defective portion can be acquired efficiently.

  Further, by acquiring an inspection image around the inspection position when the boundary B1 of the thin film 16 is not continuous, it is possible to efficiently acquire an image of a defective portion due to the roughness of the boundary B1 of the thin film 16.

  Furthermore, since the range of the defect with respect to the acquired inspection image is specified using the difference detection method, the range in which the defect is generated, the direction in which the defect is diffused, and the type of the defect itself can be specified.

In the present embodiment, the basic images PU ₀ , PA ₀ , PD ₀ of the upper bevel 15a, apex 15c, and lower bevel 15d are actually obtained from the semiconductor wafer 15 on which the thin film 15 is not formed before the defect detection of the thin film 15 is performed. However, it is also possible to acquire these basic images in advance. These basic images may be basic images acquired with respect to all rotation angle positions imaged at the time of inspection, or a specific rotation if the semiconductor wafer has the same shape at any rotation position. It may be a basic image at a position. When the basic image is acquired at each rotation angle position, it is better to use the basic image at the same rotation angle position when taking the difference from the inspection images PU _n , PA _n , PD _n .

  In the present embodiment, an example of an edge inspection apparatus having three image acquisition units is taken up. However, the present invention is not limited to this, and an edge inspection apparatus including one image acquisition unit may be used. That is, when there is one image acquisition unit, it is necessary to arrange an image acquisition unit so that an inspection image of the upper bevel can be acquired in the initial state, and to acquire an inspection image of the apex and the lower bevel. In other words, the image acquisition unit may be moved from the position for acquiring the inspection image for the upper bevel to the position for acquiring the inspection image for the apex or the position for acquiring the inspection image for the lower bevel.

  In this embodiment, the distance from the boundary between the upper bevel and the apex to the boundary of the thin film is calculated only when the upper bevel has a thin film boundary. However, the present invention is not limited to this. If there is a boundary, calculate the distance from the boundary between the lower bevel and the apex to the boundary of the thin film, or if there is a boundary of the thin film on the lower bevel, from the boundary between the lower bevel and the flat surface to the boundary of the thin film It is also possible to calculate the distance. Thus, by calculating the distance from each boundary to the boundary of the thin film, the sagging state of the thin film can be grasped.

  In the present embodiment, the distance calculation unit is provided in the image comparison unit. However, the present invention is not limited to this, and can be provided in the state acquisition unit, for example.

  In the present embodiment, the edge inspection apparatus is used. However, the function of the edge inspection apparatus of the present invention can be added to an inspection apparatus that inspects the entire surface of an object to be inspected such as a semiconductor wafer.

It is the schematic which shows the structure of the edge part inspection apparatus of this invention. It is explanatory drawing which shows the structure of a semiconductor wafer. It is a figure which shows the flow at the time of comparing with a test | inspection image when a thin film is formed in the upper bevel, and a basic image. It is a figure which shows the flow at the time of comparing with a test | inspection image and a basic image in case a thin film is formed ranging from an upper bevel to an apex. It is a figure which shows the flow which specifies a defect area | region when there is no continuity in the boundary of a thin film. It is a flowchart which shows the flow which test | inspects the edge part of a semiconductor wafer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... End part inspection apparatus, 15 ... Semiconductor wafer, 15a ... Upper bevel, 15c ... Apex, 15d ... Lower bevel, 21 ... 1st image acquisition part, 22 ... 2nd image acquisition part, 23 ... 3rd image acquisition part, 45 ... Control device, 50 ... Image comparison unit, 51 ... Status acquisition unit, 52 ... Range specifying unit, 54 ... Distance calculation unit

Claims (8)

In the end inspection apparatus that inspects the state of the end of the inspection object by imaging the end of the inspection object while rotating the disk-shaped inspection object formed with a thin film,
The surface of the object to be inspected is composed of a flat part and an inclined part that is located at the periphery of the flat part and inclines downward toward the peripheral surface of the object to be inspected.
A first image acquisition means for acquiring an image of an end of the inspection object including a part of the inclined part and the flat part from above the inspection object;
The thin film is formed on the inclined portion by comparing the basic image showing the end of the surface of the object to be inspected on which the thin film is not formed with the image acquired by the first image acquisition means. Image comparison means for recognizing whether or not,
An end portion inspection apparatus comprising: The end inspection apparatus according to claim 1,
End inspection comprising a calculating means for calculating the distance from the ridgeline between the inclined portion and the peripheral surface to the outer edge of the thin film from the image acquired by the first image acquiring means apparatus. In the edge inspection device according to claim 1 or 2,
A second image for acquiring an image of the peripheral surface of the object to be inspected at a location where the thin film intersects when the outer edge portion of the thin film intersects the ridge line between the inclined portion and the peripheral surface Acquisition means;
First state acquisition means for acquiring the correlation of the thin film on the peripheral surface from the inclined portion of the object to be inspected from the images acquired by the first image acquisition means and the second image acquisition means;
An end inspection device comprising: The end inspection device according to claim 3,
When the outer edge of the thin film intersects the ridgeline between the peripheral surface of the object to be inspected and the back surface of the object to be inspected, the back end portion of the object to be inspected at the location where the thin film intersects A third image acquisition means for acquiring an image;
From the images obtained by the second image acquisition means and the third image acquisition means, second state acquisition means for acquiring the correlation of the thin film on the back surface from the peripheral surface of the object to be inspected;
An end inspection device comprising: The end inspection device according to claim 4,
When it is determined from the thin film correlation that the boundary of the thin film is not continuous, using at least one of the first image acquisition means, the second image acquisition means, and the third image acquisition means An edge inspection apparatus for acquiring a peripheral image of a region where the thin film is not continuous. The end inspection device according to claim 5,
A range for specifying a range in which the defect is generated by a difference detection method using the defect acquired by the first image acquisition unit, the second image acquisition unit, and the third image acquisition unit and an image of the periphery thereof. An end inspection apparatus comprising a specifying means. The end inspection apparatus according to claim 6,
In addition to specifying the range in which the defect has occurred, the range specifying means can specify the diffusion direction of the defect,
Based on the specified diffusion direction of the defect, an image of the defect generated in the inspection object using at least one of the first image acquisition unit, the second image acquisition unit, and the third image acquisition unit. An edge inspection device characterized by acquiring the above. In the method of inspecting the end of the inspection object by imaging the end of the inspection object while rotating the disk-shaped inspection object,
From the upper side of the object to be inspected, an end of the surface of the object to be inspected including a part of the flat part and an inclined part that is located at the peripheral part of the flat part and is inclined downward toward the peripheral surface of the object A first step of acquiring an image in the unit;
Recognizing the presence or absence of the outer edge of the thin film in the inclined portion by comparing the basic image showing the edge of the surface of the object to be inspected on which the thin film is not formed with the image acquired in the first step A second step to
A method for inspecting an end portion of an object to be inspected.

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