JP5403653B2 - Disc-shaped substrate inspection equipment - Google Patents

Description

  The present invention relates to an inspection apparatus capable of evaluating the formation state of the film layer of a disk-shaped substrate such as a semiconductor wafer having a film layer formed on the surface thereof.

Various film layers such as an insulating film and a conductive film are concentrically formed on the surface of a semiconductor wafer (disk-shaped substrate) through a film forming process and an etching process. Conventionally, there has been proposed an inspection apparatus for detecting whether or not the edge of a film layer formed on this semiconductor wafer is in a regular finished state without turning up or the like (see Patent Document 1). In this inspection apparatus, a plurality of locations on the outer edge portion of the semiconductor wafer are photographed, an exposure width between the outer peripheral edge and the edge of the film layer in the plurality of locations of the semiconductor wafer is measured from the image obtained by the photographing, and It is determined whether or not the edge of the film layer is in a regular finished state without turning up or the like from the state of the exposed width at the plurality of locations.
JP 2002-134575 A

  By the way, in the inspection apparatus described above, the photographed image obtained at each of a plurality of locations in the circumferential direction of the semiconductor wafer is processed, and when the state of the film layer is further evaluated in detail, the semiconductor It is necessary to process a photographed image obtained by photographing over the entire circumference of the outer peripheral portion of the wafer. In addition, in order to perform a highly accurate inspection, it is necessary to obtain a captured image with a relatively high resolution.

  Under such circumstances, in a disk-shaped substrate inspection apparatus such as a semiconductor wafer having a film layer formed on the surface, image data representing a photographed image tends to increase, and efficient processing is performed. It is desired.

  The present invention has been made in view of such circumstances, and when inspecting the state of the film layer formed on the surface of the disk-shaped substrate, the processing can be performed more efficiently without sacrificing accuracy. The present invention provides an inspection apparatus for a disc-shaped substrate.

A disk-shaped substrate inspection apparatus according to the present invention is a disk-shaped substrate inspection apparatus having a film layer formed on a surface thereof, and the surface of the disk-shaped substrate on which the film layer is formed is surrounded by the periphery of the disk-shaped substrate. An imaging unit that sequentially captures images in the direction and outputs an image signal; and an image processing unit that processes the image signals sequentially output from the imaging unit, wherein the image processing unit receives the disk-shaped substrate from the image signal. Image data generating means for generating photographed image data representing a photographed image extending corresponding to the circumferential direction, display control means for displaying the photographed image on a display unit based on the photographed image data, and display on the display unit and inspection area setting means for setting an inspection area has been extended to correspond to the circumferential direction on the captured image, from the captured image data, corresponding to the film layer in the test area on the captured image In-area vertical position information representing a vertical position that is a position in a direction crossing the circumferential direction at each position in the circumferential direction of the edge line in the inspection area by detecting the edge line of the layer image portion Inspection area vertical position indicating the in-area vertical position information to be generated, the vertical position information in the area, and the vertical position at each position in the circumferential direction on the captured image of the inspection area On the captured image based on the reference portion based on the information and reference vertical position information indicating the vertical position at each position in the circumferential direction of the reference portion determined in the captured image Film layer edge position information generating means for generating film layer edge position information representing the vertical position of each edge of the film layer image portion in the circumferential direction, and the disk based on the film layer edge position information The film layer formed on the surface of the substrate. Configuration and composed with the evaluation information generating means for generating evaluation information.

With such a configuration, the vertical position information in the area representing the vertical position at each position in the circumferential direction of the edge line of the film layer image portion in the inspection area set on the photographed image, and the above-mentioned inspection area Inspection area vertical position information indicating the vertical setting position at each position in the circumferential direction on the captured image, and the vertical position at each position in the circumferential direction of the reference portion determined in the captured image The film layer edge position representing the vertical position at each position in the circumferential direction of the edge line of the film layer image part on the captured image based on the reference part based on the reference vertical position information representing Since the information is generated and the evaluation information about the film layer formed on the surface of the disk-shaped substrate is obtained based on the film layer edge position information, in order to detect the edge line of the film layer image portion, Process all shot image data corresponding to the shot image. Even if not, it is possible to obtain film layer edge position information that is the basis of evaluation information about the film layer formed on the surface of the disk-shaped substrate only by processing the image data representing the image portion in the inspection area. Become.

  Further, in the disk-shaped substrate inspection apparatus according to the present invention, the reference portion is an edge line of the surface image portion of the disk-shaped substrate on the captured image, and the surface of the disk-shaped substrate on the captured image Information on the vertical position at each position in the circumferential direction of the edge line of the image portion can be configured as the reference vertical position information.

  With such a configuration, the film layer edge position information with respect to the edge line of the film layer image portion can be obtained with reference to the edge line of the surface image portion of the disk-shaped substrate, so the evaluation obtained based on the film layer edge position information According to the information, the position of the outer peripheral edge of the film layer relative to the outer peripheral edge of the disk-shaped substrate corresponding to the edge line of the surface image portion (the outer peripheral edge of the disk-shaped substrate and the outer peripheral edge of the film layer The film layer can be evaluated based on the distance between the two.

  The inspection area set on the photographed image can be automatically set based on the standard for the formation position of the film layer formed on the surface of the disk-shaped substrate to be inspected, or manually by the operator. Can be set. In the latter case, in the disk-shaped substrate inspection apparatus according to the present invention, the inspection area setting means can be set so as to set the inspection area in accordance with a predetermined setting operation in the operation unit.

  With such a configuration, an appropriate inspection area can be set on the photographed image according to the state of the film layer formed on the surface of the disk-shaped substrate.

  Further, in the disk-shaped substrate inspection apparatus according to the present invention, the area intima layer edge position detecting means scans an image in the inspection area in a direction crossing the circumferential direction at each position in the circumferential direction, According to a predetermined condition, an edge line of the film layer image portion is detected on each scanning line, and the condition for detecting the edge line can be made variable.

  With such a configuration, conditions for detecting the edge line of the film layer image portion in the inspection area by operating the inspection area in the direction crossing the circumferential direction with respect to each position in the circumferential direction are variable. Optimum for detecting an edge line of the membrane layer image portion that is a boundary between the membrane layer image and the background portion according to the state of the membrane layer image in the inspection area and the state of the background portion of the membrane layer image It becomes possible to set various conditions.

The condition for detecting the edge line of the film layer image portion can be automatically changed according to the density (luminance) state of the film layer image portion, the density (luminance) state of the background portion, or the like. It can also be changed at In the latter case, in the disk-shaped substrate inspection apparatus according to the present invention, the area intima layer edge position detecting means variably sets the condition for detecting the edge line according to a predetermined setting operation in the operation unit. It can be constituted as follows.

  The disc-shaped substrate inspection apparatus according to the present invention further includes an area deviation determination unit that determines whether an edge line of the film layer image portion has deviated from the inspection area, and the evaluation information generation unit includes The evaluation information based on the determination result by the area deviation determination means can be generated.

  With such a configuration, the fluctuation width in the direction crossing the circumferential direction of the disc-shaped substrate at the outer peripheral edge of the film layer is within the range corresponding to the width of the inspection area (length in the direction crossing the circumferential direction). It becomes possible to evaluate the film layer, such as whether or not.

Further, in the disk-shaped substrate inspection apparatus according to the present invention, an allowable area setting means for setting an allowable area extending in the circumferential direction in the inspection area, and an edge line of the film layer image portion are the allowable values. And an allowable area deviation determination unit that determines whether or not the vehicle has deviated from the area, and the evaluation information generation unit is configured to generate evaluation information based on a determination result by the allowable area deviation determination unit. It can be constituted as follows.

  With such a configuration, the fluctuation width in the direction crossing the circumferential direction of the disc-shaped substrate at the outer peripheral edge of the film layer corresponds to the width of the allowable area set in the inspection area (length in the direction crossing the circumferential direction). It becomes possible to evaluate the film layer, such as whether or not it is within the range.

  The permissible area can be set automatically according to the size of the set inspection area or the like, or can be set manually by an operator. In the latter case, in the disk-shaped substrate according to the present invention, the allowable area setting means can be configured to set the allowable area in accordance with a predetermined setting operation in the operation unit.

  Further, the disk-shaped substrate inspection apparatus according to the present invention may be configured such that when the permissible area deviation determination unit determines that the edge line of the film layer image portion has deviated from the permissible area, Means for determining whether or not film layer edge position information about a part of the edge line of the film layer image part deviating from the permissible area is obtained, and the evaluation information generating means includes the film layer image part. The film layer edge position information is used to generate the evaluation information when it is determined that the film layer edge position information is obtained for a portion of the edge line that deviates from the allowable area. can do.

  With such a configuration, the fluctuation width in the direction crossing the circumferential direction of the disc-shaped substrate at the outer peripheral edge of the film layer corresponds to the width of the allowable area set in the inspection area (length in the direction crossing the circumferential direction). Even if it is not within the range, it is possible to evaluate how much the fluctuation range is.

  Furthermore, in the disc-shaped substrate inspection apparatus according to the present invention, when the permissible area deviation determining means determines that the edge line of the film layer image portion has deviated from the permissible area, Defect mask determination means for determining whether or not a portion of the edge line of the film layer image portion deviating from the allowable area is a portion covered with a defect portion formed on the surface of the disk-shaped substrate. And the evaluation information generation means generates the evaluation information based on the determination result of the defect mask determination means.

  With such a configuration, it is determined by the image processing that the edge line of the film layer image portion deviates from the allowable area. It is possible to distinguish whether it is caused by a defect occurring in

  According to the disk-shaped substrate inspection apparatus of the present invention, in order to detect the edge line of the film layer image portion, the image portion in the inspection area can be detected without processing all the captured image data corresponding to the captured image. By processing only the image data to be represented, it becomes possible to obtain film layer edge position information that is the basis of evaluation information about the film layer formed on the surface of the disk-shaped substrate. Since it represents the vertical position at each position in the circumferential direction with reference to the reference portion determined on the photographed image of the edge of the film layer image portion, the film layer formed on the surface of the disk-shaped substrate When inspecting the state, processing can be performed more efficiently without sacrificing accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The disk-shaped substrate inspection apparatus according to the embodiment of the present invention is realized by, for example, a semiconductor wafer surface inspection apparatus. The imaging system of this semiconductor wafer surface inspection apparatus is configured as shown in FIG. 1, for example.

  In FIG. 1, a stage 100 is held on a rotating shaft 110 a of a rotary drive motor 110 and is continuously rotated in a certain direction. On the stage 100, a semiconductor wafer (hereinafter simply referred to as a wafer) 10 serving as a disk-shaped substrate is set in a horizontal state. The stage 100 is provided with an alignment mechanism (not shown), and the wafer 10 is positioned on the stage 100 of the wafer 10 so that the center of the wafer 10 matches the rotation center of the stage 100 (the axis of the rotation shaft 110a) as much as possible. The position of is adjusted.

  A camera unit 130 (photographing unit) is installed so as to face the outer peripheral portion of the surface of the wafer 10 set on the stage 100. As shown in FIG. 2, the camera unit 130 has a line sensor 130a as an image sensor, and the line sensor 130a is arranged so as to cross the outer peripheral edge of the wafer 10 (extend in a direction perpendicular to the circumferential direction). ing. As a result, when the wafer 10 rotates in the fixed direction Dr as the stage 100 rotates, the camera unit 130 sequentially photographs the outer peripheral portion of the surface of the wafer 10 in the circumferential direction Ds. The line sensor 130a has a structure in which 1024 elements (pixels) are arranged in a line.

  Referring to FIG. 3 together with FIG. 2, a first film layer 21 is formed on the surface of the wafer 10, and a second film layer 22 is further formed on the first film layer 21. In the normal state of the first film layer 21 and the second film layer 22, at any position (θi) in the circumferential direction Ds, the outer peripheral edge portion of the lower first film layer 21 (hereinafter referred to as the outside of the first film layer). 21e is closer to the outer peripheral edge (hereinafter referred to as wafer outer peripheral edge) 10e of the wafer 10 than the outer peripheral edge (hereinafter referred to as second film layer outer peripheral edge) 22e of the second film layer 22 on the upper side. Located on the side.

  The imaging field of view range F of the camera unit 130 (line sensor 130a) is further increased from the outer peripheral portion of the wafer 10 including the first outer peripheral edge portion 21e, the second outer peripheral edge portion 22e and the outer peripheral edge portion 10e of the wafer. The portion 10e reaches slightly outside. As a result, the wafer outer peripheral edge portion 10e, the first film layer outer peripheral edge 21e, and the second film layer edge portion 22e are reflected in the captured image obtained by the camera unit 130.

  Although the illumination system is not shown in FIGS. 1 and 2, actually, the outer peripheral portion of the wafer 10 included in the photographing field-of-view range F so that an appropriate photographed image can be obtained by the camera unit 130. An illuminating device for illuminating is provided.

The processing system of the surface inspection apparatus described above is configured as shown in FIG.
In FIG. 4, the camera unit 130 is connected to a processing unit 200 (image processing unit) configured by a computer. The processing unit 200 performs drive control of the rotation drive motor 110 so that the stage 100 on which the wafer 10 is set is rotated in a predetermined direction Dr at a predetermined speed. In addition, an image signal in units of pixels is output from the camera unit 130 (line sensor 130a) that captures the outer peripheral portion of the wafer 10 while the wafer 10 rotates in accordance with the rotation of the stage 100, and the processing unit 200 performs predetermined processing. The image signals are sequentially taken in at the timing of and processed. The processing unit 200 is connected to an operation unit 210 and a display unit 220, executes processing based on a signal from the operation unit 210 operated by an operator, and captures a captured image from the input image signal. Image data is generated, and various information obtained by processing the captured image and the captured image data is displayed on the display unit 220.

  The processing unit 200 that sequentially inputs the image signals output from the camera unit 130 in which the photographing field range F is set as shown in FIG. 2 executes processing according to the procedure shown in FIGS.

  In FIG. 5, the processing unit 200 generates photographed image data representing a photographed image extending corresponding to the circumferential direction Ds from an image signal from the camera unit 130 that sequentially photographs the outer peripheral portion of the wafer 10 in the circumferential direction Ds. Then, the photographed image data is stored in a predetermined memory (S1). Then, the processing unit 200 displays the photographed image on the display unit 220 based on the obtained photographed image data (S1). On the display unit 220, for example, a photographed image I corresponding to the photographing field-of-view range F (see FIG. 3) of the camera unit 130 is displayed as shown in FIG. This photographed image I corresponds to one round of the outer peripheral portion of the wafer 10 (reference position (for example, a notch) rotation angle range of 0 to 360 degrees), and the surface corresponding to the outer peripheral portion of the wafer 10 In addition, the surface image portion I10 includes a first film layer image portion I21 corresponding to the first film layer 21 and a second film layer image portion I22 corresponding to the second film layer 22. . The photographed image I includes an edge line E10 of the surface image portion I10 that is a boundary between the surface image portion I10 and the background portion, and a first film that is a boundary between the first film layer image portion I21 and the surface image portion I10. An edge line E21 of the layer image portion I21 and an edge line E22 of the second film layer image portion I22 which is a boundary between the second film layer image portion I22 and the first film layer image portion I21 are formed.

  The edge line E10 of the surface image portion I10 corresponds to the outer peripheral edge portion 10e (see FIG. 2) of the wafer 10, and the edge line E21 of the first film layer image portion I21 is the outer peripheral edge portion 21e of the first film layer 21 (see FIG. 2). The edge line E22 of the second film layer image portion I22 corresponds to the outer peripheral edge portion 22e (see FIG. 2) of the second film layer 22. The edge line E10 of the surface image portion I10 corresponding to the outer peripheral edge portion 10e of the wafer 10 should be a straight line. However, since the outer peripheral edge portion 10e can vary in the radial direction of the wafer 10 (diameter variation) depending on the processing accuracy of the end face of the wafer 10, the success or failure of the processing process, etc., the edge line of the surface image portion I10 on the photographed image I As shown in FIG. 8, E10 can vary in the direction orthogonal to the circumferential direction (hereinafter referred to as the longitudinal direction) over the circumferential direction (0 to 360 degrees).

  As described above, when the captured image I as shown in FIG. 8 is displayed on the display unit 220, the processing unit 200 displays the film layer image portions (first film layer image portion I21, second film layer image portion I22). ) The edge line (E21, E22) detection process (S2) is executed. Specifically, the edge detection processing of the film layer image portion is performed as shown in FIG.

In FIG. 6, when the setting operation of the inspection area is performed in the operation unit 210, the processing unit 200 moves the circumferential direction (0 degree) of the wafer 10 on the photographed image I displayed on the display unit 220 according to the setting operation. An inspection area extending corresponding to (~ 360 degrees) is set (S21). For example, as shown in FIG. 9, the first inspection area Z1 including the edge line E21 of the first film layer image portion I21 and the second inspection area Z2 including the edge line E22 of the second film layer image portion I22 are set. . FIG. 6 shows processing for one inspection area. In this example, the reference detection area Z0 including the edge line E10 of the surface image portion I10 is set together with the inspection areas Z1 and Z2. The reference detection area Z0 is also processed in substantially the same manner as the inspection areas Z1 and Z2, as will be described later.

In the setting of the inspection areas Z1 and Z2, the processing unit 200 determines the set positions of the inspection areas Z1 and Z2 on the captured image I based on the signal input from the operation unit 210 in response to the setting operation. Get the width (length in the vertical direction). For example, as shown in FIG. 9, the lower limit position in the vertical direction of the first inspection area Z1 is acquired as the set position of the first inspection area Z1. Information indicating the lower limit position (set position) of the first inspection area Z1 is referred to as first inspection area vertical direction position information Y _Z11 . Further, the lower limit position in the vertical direction of the second inspection area Z2 is acquired as the setting position of the second inspection area Z2. Information indicating the lower limit position (set position) of the second detection area Z2 is referred to as second inspection area vertical direction position information Y _Z21 . The processing unit 200 determines the upper limit position Y _Z12 in the vertical direction of the first inspection area Z1 and the vertical direction of the second inspection area Z2 based on the width of each inspection area acquired together with the set position (lower limit position). The upper limit position Y _Z22 can be recognized.

Similarly, for the reference detection area Z0, the lower limit position (reference area vertical direction position information Y _Z0 ) in the vertical direction of the reference detection area Z0 is acquired as the set position on the captured image I.

  When the processing unit 200 acquires the setting positions and widths of the inspection areas Z1 and Z2, the processing unit 200 extracts image data in the inspection areas Z1 and Z2 specified by the setting positions and widths from the captured image data I. Processing is individually performed on images in each of the inspection areas Z1 and Z2 as shown in FIGS. 10 (a) and 10 (b). The processing unit 200 first performs an averaging (integration) process in the circumferential (θ) direction (S22). Specifically, while moving the pixel of interest one pixel at a time in the circumferential direction (lateral direction), each gray value of each pixel of interest and a predetermined number of pixels sandwiching it in the circumferential direction is averaged, and the averaged gray value is calculated. Processing for setting the gray value of the target pixel is performed. Even if, for example, a pattern pattern (for example, a chip pattern) is formed on the film layer by the averaging process in the circumferential direction (θ), the pattern pattern is formed in the film layer image portion (in the inspection area). The corresponding shading pattern is smoothed, and noise on the image is removed. Next, the processing unit 200 scans in the vertical direction at each position (θi) while shifting the circumferential position (θi) on the image of each inspection area Z1, Z2 by a predetermined width (for example, once). Then, edge detection on the image is performed (S23).

  This edge detection process is basically a differentiation process. For example, while moving the target pixel one pixel at a time in the vertical direction, the sum of the gray values of a predetermined number of pixels positioned above the target pixel in the vertical direction. And the difference between the sum of the shade values of a predetermined number of pixels located below the pixel value is calculated as a differential value of the pixel of interest. As a result of such processing, the difference is increased at the pixel of interest at a position where the gray value varies rapidly in the vertical direction, and the difference is decreased at the pixel of interest at a position where the variation of the gray value is small. As a result of such differential processing, for example, as shown in FIG. 11A, the boundary between the first film layer image portion I21 and the second film layer image portion I22 (the edge line E21 of the first film layer image portion I21). ), The primary differential waveform changes as shown in FIG. 11B, and the secondary differential waveform changes as shown in FIG. 11C. When such a differential waveform of the image is obtained at each position (θi) in the circumferential direction, the processing unit 200 causes the display unit 220 to display the differential waveform at the designated circumferential position (θi) (S24). ). The operator scans the inspection areas Z1 and Z2 for detecting the edge line of the film layer image portion while observing the peak fluctuation state of the differential waveform at each position (θi) in the circumferential direction (from the lower limit position to the upper limit). A direction toward the position, a direction from the upper limit position toward the lower bound position) and a threshold level to be detected as an edge line (these are conditions for edge line detection) are set by operating the operation unit 210 (S25). , S26).

As described above, when the conditions for detecting the edge lines E21 and E22 of the film layer image portions I21 and I22 are set in the inspection areas Z1 and Z2, the processing unit 200 performs the differential image ( The first-order differential waveform information or the second-order differential waveform information) is scanned in the vertical direction while shifting the position (θi) in the circumferential direction by a predetermined width (for example, once), and each circumferential direction is referenced based on the threshold value. The edge lines E21 and E22 are detected at the position (θi) (S27). Specifically, in the detection process of the edge line E21 of the first film layer image portion I21, as shown in FIG. 10B, the position of the edge line E21 at each circumferential position (θi) is subjected to the first inspection. In the first area vertical direction position information y _Z1 (θi) expressed as a distance from the lower limit position of the area Z1, the detection processing of the edge line E22 of the second film layer image portion I22 is performed as shown in FIG. ), Vertical position information y _Z2 (θi) in the second area representing the position of the edge line E22 at each circumferential position (θi) as a distance from the lower limit position of the second inspection area Z2 is generated. The

The reference detection area Z0 including the edge line E10 of the surface image portion I10 corresponding to the outer peripheral edge portion 10e (see FIG. 2) of the wafer 10 is the same as the processing (S22 to S27) for the inspection areas Z1 and Z2. In the reference area, the position of the edge line E10 of the surface image portion I10 at each circumferential position (θi) is expressed as a distance from the lower limit position of the reference detection area Z0, as shown in FIG. Vertical position information y _Z0 (θi) is generated.

  Next, the processing unit 200 includes film layer edge position information Y (θi) indicating the vertical position at each circumferential position (θi) of the edge lines E21 and E22 of the film layer image portions I21 and I22 on the captured image I. ) Is generated (S28).

Specifically, first, a reference vertical position Ys (θi) representing a vertical position at each position (θi) in the circumferential direction of the edge line E10 of the surface image portion I10 in the photographed image I is the reference detection area Z0. Using the reference area vertical position information Y _Z0 (θi) representing the installation position of the image and the reference area vertical position information y _Z0 (θi) of the edge line E10 of the surface image portion I10,
Ys (θi) = Y _Z0 (θi) + y _z0 (θi)
(See FIG. 9 and FIG. 10C).

Next, using this reference vertical direction position information Ys (θi), the film layer edge representing the vertical position at each circumferential position (θi) for the edge lines E21 and E22 of the film layer image portions I21 and I22 Position information Y ₁ (θi), Y ₂ (θi) is calculated.

For the edge line E21 of the first film layer image portion I21, the vertical direction value information y _Z1 (θi) in the first area and the first inspection area vertical direction position information Y indicating the set position of the first inspection area Z1. _{Using Z11} (θi) and the reference vertical position information Ys (θi), the film layer edge position information Y ₁ (θi) is
Y ₁ (θi) = Y _Z11 (θi) + y _Z1 (θi) −Ys (θi)
Is calculated according to

Further, regarding the edge line E22 of the second film layer image portion I22, the second area vertical position information y _Z2 (θi) and the second inspection area vertical position information indicating the set position of the second inspection area Z2. Using Y _Z21 (θi) and the reference vertical position information Ys (θi), the film layer edge position information Y ₂ (θi)
Y ₂ (θi) = Y _Z21 (θi) + y _Z2 (θi) −Ys (θi)
Is calculated according to

The film layer edge position information Y ₁ (θi), Y ₂ (θi) for the edge lines E21, E22 of the film layer image portions I21, I22 calculated according to the above equations is the surface image I10 on the photographed image I. The vertical position with respect to the edge line E10, that is, the distance from the edge line E10 of the surface image I10 is shown.

As described above, the circumferential directions of the edge line E21 of the first film layer image portion I21 and the edge line E22 of the second film layer image portion I22 on the photographed image I on the basis of the edge line E10 of the surface image portion I10. When the film layer edge position information Y ₁ (θi), Y ₂ (θi) representing the vertical position at each position (θi) is obtained, the processing unit 200 returns to FIG. Evaluation information about the corresponding film layer is generated based on the information Y (θi) (S3). The evaluation information generation process is specifically performed as shown in FIG.

For example, an evaluation process for the first film layer 21 corresponding to the first film layer image portion I21 in the first inspection area Z1 will be described as an example. In FIG. 7, the processing unit 200 has a circumferential direction position information y _Z1 (θi) (see FIG. 10B) in the first area with respect to the edge line E21 of the first film layer image portion I21 in the circumferential direction. By determining whether or not the position (θi) exists, it is determined whether or not the edge line E21 of the first film layer image portion I21 exceeds (is deviated from) the first inspection area Z1 (S31). ). Determination that the edge line E21 of the first film layer image portion I21 is within the first inspection area Z1 over all positions (θ) in the circumferential direction (see FIGS. 9 and 10B) (YES in S31) Then, the processing unit 200 extracts the maximum value Y _max and the minimum value Y _min of the film layer edge position information Y ₁ (θi) at all the positions (θi) in the circumferential direction ( S33, S34). Further, the processing unit 200 calculates the average value Y _ave and the standard deviation value Y _std of the film layer edge position information Y ₁ (θi) at all circumferential positions (θi) (S36). Then, the processing unit 200 displays the maximum value Y _max , the minimum value Y _min , the average value Y _ave , and the standard deviation value Y _std on the display unit 220 as evaluation information of the first film layer 21 (S37).

From the maximum value Y _max , the minimum value Y _min , the average value Y _ave , and the standard deviation value Y _std as the evaluation information of the first film layer 21 displayed on the display unit 220, the operator can _move the outside of the first film layer 21. It is possible to know the maximum value, minimum value, average value, and standard deviation value of the distance between the peripheral edge portion 21e and the outer peripheral edge portion 10e of the wafer 10, and based on this, the formation position and shape of the first film layer 21, The suitability of the film formation process can be determined.

For example, as shown in FIGS. 12 and 13, when the edge line E22 of the second membrane layer image portion I22 deviates from the second inspection area Z2, the edge line E22 of the second membrane layer image portion I22 In the circumferential position range (angle range) θi to θj, the vertical position information y _Z2 (θ) in the second area is not obtained (see S27 in FIG. 6). In this case, in the process of the evaluation information generation process for the second membrane layer 22 corresponding to the second membrane layer image portion I22, the processing unit 200 performs the vertical direction in the second area with respect to the edge line E22 of the two membrane layer image portion I22. It is determined that there are circumferential positions θi to θj where position information y _Z2 (θi) is not obtained, that is, the edge line E22 of the second film layer image portion I22 exceeds the second inspection area Z2 (deviation) (Yes in S31). Then, the processing unit 200 stores the status information ST that the edge line E22 of the second film layer image portion I22 exceeds the second inspection area Z2 in the range of the circumferential position range θi to θj, and the second The number n (corresponding to the range of θi to θj) of positions (locations) in the circumferential direction where the edge line E22 of the film layer image portion I22 has deviated is stored (S32). Then, the processing unit 200 uses the film layer edge position information Y ₂ (θi) obtained in a range where the edge line E22 does not deviate from the second inspection area Z2, and the maximum value Y _max and the minimum value Y _min was extracted (S33, S34), and the edge line E22 deviated from the obtained film layer edge position information Y ₂ (θi) and the number N of all the positions in the circumferential direction (for 360 degrees). The average value Y _ave and the standard deviation value Y _std of the film layer edge position information Y ₂ (θi) are calculated using the number obtained by subtracting the number n of positions (locations) in the circumferential direction (S35, S36). Processing unit 200, the maximum value obtained Y _max, the minimum value Y _min, the average value Y _ave, with standard deviation value Y _std, position range of the edge line E22 of the second film layer image part I22 circumferential direction θi~θj Then, the status information ST indicating that the second inspection area Z2 is exceeded is displayed on the display unit 220 as the evaluation information of the second film layer 22 (S37).

  The operator can know that there is a portion (θi to θj) where the second film layer 22 is not formed within the normal range based on the status information ST displayed on the display unit 220, and The maximum value, the minimum value, the average value, and the standard deviation value of the distance between the outer peripheral edge portion 22e of the second film layer 22 and the outer peripheral edge portion 10e of the wafer 10 in the excluded range can be known. Based on the evaluation information, the formation position and shape of the second film layer 22 and the suitability of the film formation process can be determined.

According to the surface inspection apparatus for the wafer 10 as described above, in order to detect the edge lines E21 and E22 of the film layer image portions I21 and I22, it is not necessary to process all the captured image data corresponding to the captured image I. Film layer edge position information Y ₁ (θi) that serves as a basis for evaluation information on the film layers 21 and 22 formed on the surface of the wafer 10 only by processing image data representing image portions in the inspection areas Z1 and Z2. , Y ₂ (θi) can be obtained, and the film layer edge position information Y ₁ (θi), Y ₂ (θi) are taken images of the edge lines E21, E22 of the film layer image portions I21, I22. A vertical position at each position in the circumferential direction with respect to the edge line E10 of the surface image portion I10 on I (between the outer peripheral edge portions 21e and 22e of the film layers 21 and 22 and the outer peripheral edge portion 10e of the wafer 10 Formed on the surface of the wafer 10. When inspecting the state of each of the film layers 21 and 22, the processing can be performed more efficiently without sacrificing accuracy.

  Furthermore, in the above-described example, conditions (scanning direction, threshold level) for detecting the edge lines E21 and E22 of the corresponding film layer image portions I21 and I22 are set for each of the inspection areas Z1 and Z2. Even if the state of the image area including the edge lines E21 and E22 of the film layer image portions I21 and I22 (contrast state between the film layer image portion and its background portion, noise state, etc.) is different. In addition, both of the edge lines E21 and E22 of the film layer image portions I21 and I22 can be detected according to appropriate conditions. That is, the detection accuracy can be improved.

  The edge line detection process (S2) of the film layer image portion shown in FIG. 5 can be performed according to the procedure shown in FIG. This process is different from the above-described process (FIG. 6) in that an allowable area is set in each of the inspection areas Z1 and Z2. In this case, the evaluation information generation process (S3) is performed as shown in FIG. 15, for example.

In FIG. 14, when an operation area setting operation is performed in the operation unit 210, the processing unit 200 sets the inspection areas Z <b> 1 and Z <b> 2 on the captured image I displayed on the display unit 220 in accordance with the setting operation. (S21) Furthermore, two determination lines L _Zn1 and L _Zn2 extending corresponding to the circumferential direction are set for each of the inspection areas Z1 and Z2 (S211). Specifically, as shown in FIG. 16, two determination lines L _Z11 and L _Z12 extending corresponding to the circumferential direction are set at a substantially central portion in the vertical direction of the first inspection area Z1. In addition, two determination lines L _Z21 and L _Z22 extending corresponding to the circumferential direction are set at a substantially central portion in the vertical direction of the second inspection area Z2. A region sandwiched between the two determination lines L _Zn1 and L _Zn2 in each inspection area Z1 and Z2 is an allowable area.

Thereafter, the processing unit 200 extracts the image data in each inspection area Z1, Z2 set from the photographed image data, and images in each inspection area Z1, Z2 as shown in FIGS. 17 (a) and 17 (b). The same processing as in the above-described example (see S22 to S28 in FIG. 6) is performed. As a result, the processing unit 200 sets the film layer edge position information Y ₁ (θi) for the edge line E21 of the first film layer image portion I21, the vertical position information y _Z1 (θi) in the first area, and the first Using the first inspection area vertical position information Y _Z11 (θi) representing the set position of the inspection area Z1 and the reference vertical position information Ys (θi),
Y ₁ (θi) = Y _Z11 (θi) + y _Z1 (θi) −Ys (θi)
The film layer edge position information Y ₂ (θi) for the edge line E22 of the second film layer image portion I22, the vertical position information y _Z2 (θi) in the second area, and the second inspection area Z2 Using the second inspection area vertical position information Y _Z21 (θi) representing the set position of the reference vertical position information Ys (θi),
Y ₂ (θi) = Y _Z21 (θi) + y _Z2 (θi) −Ys (θi)
Calculate according to

In this example, the vertical widths of the inspection areas Z1 and Z2 are set wider than those in the above-described example (see FIGS. 9 and 10). The width in the vertical direction of the allowable area (the interval between the two determination lines L _Zn1 and L _Zn2 ) can be set to be approximately the same as the width of the inspection areas Z1 and Z2 in the above-described example.

When the film layer edge position information Y ₁ (θi) and Y ₂ (θi) of the edge line E21 of the first film layer image portion I21 and the edge line E22 of the second film layer image portion I22 are obtained, the processing unit 200 The evaluation information processing is executed according to the procedure shown in FIG.

In FIG. 15, the processing unit 200, based on the vertical position information y _Z1 (θi), y _Z2 (θi) in each area, in each inspection area Z1, Z2, the edge line E21 of the film layer image portions I21, I22. , E22 is judged whether it exceeds the judgment lines L _Zn1 and L _Zn2 (S311). For example, as shown in FIG. 16 and FIG. 17 (a), the case edge line E22 of the second film layer image part I22 is in the circumferential direction of the position range Shitaai～shitaj, exceeding the judgment line L _Z21, processing unit 200 In the process of evaluation information processing for the second membrane layer 22 corresponding to the second membrane layer image portion I22, the edge line E22 of the second membrane layer image portion I22 exceeds the judgment line L _Z21 (the allowable area is Is deviated) (YES in S311). Then, the processing unit 200 stores status information ST that the edge line E22 of the second film layer image portion I22 exceeds the determination line L _Z21 in the circumferential position range (angle range) θi to θj. The number n (j−i) of positions (locations) in the circumferential direction where the edge line E22 of the second film layer image portion I22 has deviated is stored (S312). Thereafter, the processing unit 200 determines film layer edge position information Y ₂ (θi) to Y for the edge line E22 in the position range θi to θj where the edge line E22 of the second film layer image portion I22 exceeds the determination line L _Z21 . ₂ whether or not it is possible to compensate for (.theta.j), i.e., whether the film layer edge position information Y ₂ of the edge line E22 at the position range _{θi~θj (θi) ~Y 2 (θj} ) has already been obtained Is determined (S313). Then, if there edges line E22 at the position range θi~θj within the inspection area Z2, the position range θi~θj film layer edge position of the edge line E22 in the information _{Y 2 (θi) ~Y 2 (} θj) is If already acquired (YES in S313), the processing unit 200 determines the film layer edge position information Y _{2 of the} position range θi to θj where the edge line E22 of the second film layer image portion I22 exceeds the determination line L _Z21. (Θi) to Y ₂ (θj) are supplemented as basic information of the evaluation information (S314).

Then, the processing unit 200 resets the number n (corresponding to the range of θi to θj) of the position (location) where the edge line E22 of the second film layer image portion I22 has deviated to zero (S315), The maximum value Y _max and the minimum value Y _min of the film layer edge position information Y ₂ (θi) at all the positions (θi) in the circumferential direction are extracted (S33, S34). An average value Y _ave and standard deviation value Y _std of film layer edge position information Y ₂ (θi) at all positions (θi) in the direction are calculated (S36). In the processing unit 200, the maximum value Y _max , the minimum value Y _min , the average value Y _ave , the standard deviation value Y _std, and the edge line E22 of the second film layer image portion I22 are in the circumferential position range (angle range). Status information ST indicating that the judgment line L _Z21 is exceeded in the range of θi to θj is displayed on the display unit 220 as evaluation information (S37).

The operator can know that there is a portion (θi to θj) where the second film layer 22 is not formed within the allowable range based on the status information ST as the evaluation information displayed on the display unit 220. Further, the operator assumes that the second film layer 22 is formed beyond the allowable range, and the maximum value Y _max as the evaluation information of the second film layer 22 displayed on the display unit 220 is the minimum value. From the value Y _min , the average value Y _ave , and the standard deviation value Y _std , the maximum value, minimum value, average value, and standard deviation of the distance between the outer peripheral edge portion 22e of the second film layer 22 and the outer peripheral edge portion 10e of the wafer 10 are obtained. You can know the value. Therefore, even if the second film layer 22 is formed beyond the allowable range, the formation position and shape of the second film layer 22 and the suitability of the film formation process can be determined over the entire circumference of the wafer 10. It becomes like this.

For example, in the process of evaluation information processing for the first film layer 21 corresponding to the first film layer image portion I21, the edge line E21 of the first film layer image portion I21 is determined as shown in FIG. If it is determined that the lines L _Z11 and L _Z12 are not _exceeded (does not deviate from the permissible area) (NO in S311), the status information ST is not generated and all the positions in the circumferential direction ( The maximum value Y _max and the minimum value Y _min of the film layer edge position information Y ₁ (θi) at θi) and the film layer edge position information Y at all the positions (θi) in the circumferential direction thereof. The average value Y _ave of ₁ (θi) and its standard deviation value Y _std are obtained as evaluation information (S33 to S36). Then, the evaluation information is displayed on the display unit 220 (S37).

Further, in the process of the evaluation information processing for the second film layer 22 corresponding to the second film layer image portion I22 described above, the position range in which the edge line E22 of the second film layer image portion I22 exceeds the determination line L _Z21. it is impossible to compensate for the film layer edge position information _{Y 2 (θi) ~Y 2 (} θj) for the edge line E22 in Shitaai～shitaj, i.e., edge line E22 of the second film layer image part I22 is the position range θi~ If the second inspection area Z2 to be deviating by layer edge position information Y ₂ of that range (θi) ~Y ₂ (θj) it is determined that is not obtained made in .theta.j (nO in S313), The maximum value Y _max and the minimum value Y _min are extracted using the film layer edge position information Y (θi) obtained in a range where the edge line E22 does not exceed the determination line L _Z21 (S33, S34), The obtained film layer edge position information Y (θi) and all of the circumferential direction Position using the number of the edge line E22 from the number N is minus the number n of positions (portions) in the circumferential direction exceeds the judgment line L _Z21 of (360 degrees), the film layer edge position information Y ( An average value Y _{ave of} θi) and its standard deviation value Y _std are calculated (S35, S36).

When the determination lines L _Zn1 and _Zn2 (allowable areas) are set in the inspection areas Z1 and Z2 (when the edge line inspection process for the film layer image portion shown in FIG. 14 is performed), the processing unit 200 performs the evaluation information generation process. (S3) can be executed according to the procedure shown in FIGS. In this process, for example, as shown in FIG. 20, even when a defect D (M) exists in the inspection area Z1, appropriate evaluation information for the film layer can be obtained.

For example, as shown in FIG. 20, when there is a defect image portion D (M) related to the determination lines L _Z11 and L _Z12 in the circumferential position range θm to θn in the first inspection area Z1, the processing unit 200 In the process of evaluation information processing for the first film layer 21 corresponding to the one film layer image portion I21, the edge line of the first film layer image portion I21 is affected by the defect image portion D (M) in the position range θm to θn. It is determined that E21 exceeds the determination lines L _Z11 and L _Z12 (departs from the allowable area) (YES in S311). Then, the processing unit 200 receives status information ST indicating that the judgment lines L _Z11 and L _Z12 are exceeded in the circumferential position range (angle range) θm to θn of the edge line E21 of the first film layer image portion I21. The number n (corresponding to the range of θm to θn) of positions (locations) in the circumferential direction where the edge line E22 of the first film layer image portion I21 has deviated is stored (S312). Next, the processing unit 200 detects film layer edge position information Y ₁ (θm) for the edge line E21 in the position range θm to θn where the edge line E21 of the first film layer image portion I21 exceeds the determination lines L _Z11 and L _Z12. ) To Y ₁ (θn) cannot be supplemented, that is, the film layer edge position information Y ₁ (θm) to Y ₁ (θn) for the edge line E21 in the position range θm to θn has not been acquired. (NO in S313), the process proceeds to the process shown in FIG.

In FIG. 19, the processing unit 200 determines whether or not the mask designation for ignoring the defect images on the determination lines L _Z11 and L _Z12 in the first inspection area Z1 has been made (S316). If it is determined that this mask designation has been made (YES in S316), the processing unit 200 stores the status STm for the mask location corresponding to the defect image portion D (M) (S317). Thereafter, the processing unit 200 returns to the processing shown in FIG. 18, and the film layer edge position information Y ₁ (in the range in which the edge line E21 does not exceed the determination lines L _Z11 , L _Z12 ) The maximum value Y _max and the minimum value Y _min are extracted using θi) (S33, S34), the obtained film layer edge position information Y ₁ (θi) and all the positions in the circumferential direction (360 degrees) The film layer edge position information Y is obtained by subtracting the number n of positions (locations) in the circumferential direction that the edge line E21 has exceeded the judgment lines L _Z11 and L _Z12 from the number N of minutes). An average value Y _ave of (θi) and its standard deviation value Y _std are calculated (S35, S36).

In the processing unit 200, the maximum value Y _max , the minimum value Y _min , the average value Y _ave , the standard deviation value Y _std, and the edge line E21 of the first film layer image portion I21 are in the circumferential position range (angle range) θm. Status information ST that the judgment lines L _Z11 and L _Z12 are exceeded in the range of .about..theta.n and the status STm for the mask location corresponding to the defect image portion D (M) are displayed on the display unit 220 as evaluation information (S37). .

The operator can know that there is a portion (θm to θn) where the first film layer 21 is not formed within the allowable range based on the status information ST and STm as evaluation information displayed on the display unit 220. At the same time, it can be known that it has been judged as such due to defects. In addition, the operator assumes that the second film layer 22 is affected by the defect, and the maximum value Y _max , the minimum value Y _min as the evaluation information of the first film layer 21 displayed on the display unit 220, From the average value Y _ave and the standard deviation value Y _std , the maximum value, minimum value, average value, and standard deviation value of the distance between the outer peripheral edge portion 21e of the first film layer 21 and the outer peripheral edge portion 10e of the wafer 10 are known. Can do. Based on the evaluation information, the formation position and shape of the first film layer 21 and the suitability of the film formation process can be determined.

  In each example described above, the first inspection area Z1, the second inspection area Z2, and the reference detection area Z0 have a rectangular shape, but are not limited thereto. These areas can be set in an inclined shape on the captured image, or can have an arbitrary shape such as an elliptical shape. The present invention is not limited to the semiconductor wafer inspection apparatus described above, and can be applied to other disk-shaped substrate inspection apparatuses such as DVDs.

  In the surface inspection apparatus for the wafer 10 described above, the inspection areas Z1 and Z2 and the reference detection area Z0 are set according to the operation of the operation unit 210 by the operator (processing in S21 in FIGS. 6 and 14). The processing unit 200 may automatically set based on the shape standard of the wafer 10 and the formation specification of the film layer.

In this case, edge detection is performed on the captured image I by scanning in the vertical direction every predetermined angle in the circumferential direction. By this edge detection processing, for example, as shown in FIG. 21, the vertical position Y (θ) of the edge line E22 of the second film layer image portion I22 is obtained at predetermined angular intervals. Then, the minimum value of the vertical position, for example, the vertical position extended from the vertical position Y _MIN of the edge line E22 at the angular position θi by a predetermined amount outside the second film layer image portion I22 is the second inspection. This is recognized as the lower limit position Y _Z21 of the area Z2. The maximum value of the longitudinal position of said edge line E22, for example, by a predetermined amount from the longitudinal position Y _MAX on the inner side of the second film layer image part I22 of the edge line E22 at the angular position theta = 360 ° unfolded vertical The direction position is recognized as the upper limit position Y _Z22 of the second inspection area Z2.

  The fluctuation period of the vertical position of the edge line of each film layer is generally very large (not small) due to the film forming process. Accordingly, the edge detection performed for setting the inspection area can be performed at a relatively large angular interval. Therefore, the inspection area can be automatically set without extremely increasing the processing amount.

  Further, in the specific edge line detection process of the film layer image portion shown in FIGS. 6 and 14, the average (integration) process (S22) in the circumferential direction is performed on the entire captured image I, and then the average is obtained. The edge detection (differentiation) process at each circumferential position (θi) is performed on the captured image that has undergone the conversion process, but the averaging process in the circumferential direction is performed for each pixel (target pixel) of the captured image I And edge detection processing can also be performed.

  In this case, as shown in FIG. 22, an n × m (pixel) window W is set on the captured image I, and the window W is moved in the vertical direction and the horizontal direction, and is located at the center of the window W. The pixels are subjected to averaging (integration) processing in the horizontal direction (circumferential direction of the wafer 10) using the gray value D of the surrounding pixels, and edge detection processing is performed in the vertical direction. A specific process will be described with reference to FIGS. 23 to 26, taking the case of a 5 × 7 window W as an example.

In FIG. 23, the gray value D ₀ of the target pixel (shaded portion) and the gray values D ₋₂ , D ₋₁ , D ₊₁ , and D _{+2 of the} two pixels before and after the horizontal direction are averaged. An averaged gray value is obtained. The average gray value is, for example,
_{(D -2 + D -1 + D} 0 + D +1 + D +2) / 5
It is calculated as follows. Here, the sum D ₋₂ + D ₋₁ + D ₀ + D ₊₁ + D ₊₂ of the gray value of each pixel in the row of the target pixel (D ₀ ) in the window W is described as Σ ₀ .

According to the same method, each pixel (D ⁻³ , D ⁻² , D ⁻¹ , D ⁺¹ , D ⁺² , D ⁺³ ) in the column of the target pixel (D ₀ ) in the window W is described. It is assumed that an average gray value is obtained. In the process, the sum Σ ₋₃ , Σ ₋₂ , Σ ₋₁ , Σ ₊₁ , Σ ₊₂ , and Σ ₊₃ of the gray value of the target pixel and the five pixels in the horizontal direction across the pixel are obtained. .

In such a situation, edge detection (differentiation) processing is performed. Specifically, the sum ΣA ₀ of the average gray values of the three pixels (D ⁺¹ , D ⁺² , D ⁺³ ) located above the pixel of interest (D ₀ ) in the vertical direction is calculated, and The sum ΣB ₀ of the average gray values of the three pixels (D ⁻¹ , D ⁻² , D ⁻³ ) located below the pixel (D ₀ ) in the vertical direction is calculated. And
ΣA ₀ -ΣB ₀
Is calculated as a differential value of the pixel of interest (D _o ). When the absolute value of the differential value is equal to or greater than a predetermined value, it means that there is a large variation in light and shade with the target pixel (D ₀ ) as a boundary (the target pixel corresponds to the edge portion).

Next, the window W is shifted upward by one pixel in the vertical direction. Then, the relationship between the window W and each pixel is as shown in FIG. In FIG. 24, the average gray value of the pixel (D ⁺⁴ ) located at the center is calculated based on the gray value of the pixels for one row newly entered in the window W. Then, the pixel (D ⁺¹ ) (shaded portion) located in the center of the window W becomes the target pixel, and the same processing as that for the target pixel (D ₀ ) is performed on the pixel.

Since the average gray value of the pixel of interest (D ^{+ 1} ) has already been obtained, edge detection (differentiation) processing is performed. Specifically, the summation ΣA ₁ of the average gray values of the three pixels (D ⁺² , D ⁺³ , D ⁺⁴ ) located above the target pixel (D ⁺¹ ) in the vertical direction is calculated, The sum ΣB ₁ of the averaged gray values of the three pixels (D ₀ , D ⁻¹ , D ⁻² ) located below the pixel of interest (D ⁺¹ ) in the vertical direction is calculated. And
ΣA ₁ −ΣB ₁
Is obtained as a differential value of the pixel of interest (D ⁺¹ ).

The sum ΣA ₁ of the averaged gray values of the three pixels is not added to the average gray value of each pixel, but the average gray value E ⁺ of the pixel (D ⁺⁴ ) is added to the previously obtained sum ΣA _0. ^{It is obtained} by adding ⁴ and subtracting the average gray value E ⁺¹ of the pixel (D ⁺¹ ) that has now become the pixel of interest (see the following equation).
ΣA ₁ = ΣA ₀ + E ⁺⁴ −E ⁺¹
Similarly, with respect to the sum ΣB ₁ of the averaged gray values of the three pixels arranged below the ^target pixel (D ⁺¹ ) in the vertical direction, the average gray level of the pixel (D ₀ ) is also added to the previously obtained sum ΣB _0. It is obtained by adding the value E ₀ and subtracting the average gray value E ^-3 of the pixel (D ^-3 ).
ΣB ₁ = ΣB ₀ + E ₀ −E ⁻³

Further, the window W is shifted upward by one pixel in the vertical direction. Then, the relationship between the window W and each pixel is as shown in FIG. In FIG. 25, the average gray value of the pixel (D ⁺⁵ ) located at the center is calculated based on the gray value of the pixel for one row newly entered in the window W. The pixel located in the center of the window W (D ⁺²⁾ (hatched portion) is a target pixel, with respect to the target pixel, the same edge detection process as for the previous pixel of interest D ⁺¹ is made. That is, the summation ΣA ₂ of the average gray values of the three pixels (D ⁺³ , D ⁺⁴ , D ⁺⁵ ) located above the target pixel (D ⁺² ) in the vertical direction is calculated, and the target pixel ( The sum ΣB ₂ of the average gray values of the three pixels (D ⁺¹ , D ₀ , D ^-1 ) located below in the vertical direction of D ⁺² ) is calculated. And
ΣA ₂ -ΣB ₂
Is obtained as a differential value of the pixel of interest (D ⁺² ).
The sums ΣA ₂ and ΣB ₂ are obtained by calculation using the sum obtained previously, as described above.

As described above, while moving the window W one pixel at a time in the vertical direction, the averaging (integration) process for one line and the edge detection (differentiation) process for the pixel of interest are repeated, and the edge of the inspection area in the vertical direction is repeated. When reaching, the window W is shifted by one pixel in the horizontal direction (corresponding to the circumferential direction of the wafer 10). For example, when the window W in the state of FIG. 23 is shifted by one pixel in the horizontal direction, the relationship between the window W and each pixel is as shown in FIG. In FIG. 26, a pixel (for example, D ₊₁₎ located at the center of each row in the window W is added with the gray value of each pixel in the column (D ₊₃ column) newly entered in the window W. Etc.) is calculated. For example, when the pixel (D ₊₁ ) is the target pixel, the average gray value is
(D _-1 + D ₀ + D ₊₁ + D ₊₂ + D ₊₃ ) / 5
Obtained according to

Here, if the sum total _{D -1 + D 0 + D +1} + D +2 + D +3 gray value of each pixel in the row of the pixel of interest (D ₊₁₎ within the window W is described as sigma _01, the sum described above .SIGMA.A ₁ As in the case of ΣB ₁ , the previously obtained sum Σ ₀ and the gray value D _{+3 of} the pixel (D ₊₃ ) newly entered in the window W by shifting the window W by one pixel , Using the gray value D _{-2 of} the pixel (D _-2 ) coming out of the window W,
Σ ₀₁ = Σ ₀ + D ₊₃ −D ₋₂
Is calculated according to

When the average gray value for each pixel in the column including the pixel (D ₊₁ ) in the window W is obtained in this way, the pixel (in the same manner as described with reference to FIGS. 23 to 25). Edge detection processing is performed in a column (vertical direction) including D + 1). Thereafter, every time the window W is shifted by one pixel in the horizontal direction, the same gradation value averaging (integration processing) and edge detection (differentiation) processing as described above is performed.

  If the averaging process in the circumferential direction and the edge detection (differentiation) process in the vertical direction are performed on the captured image I as described above, the process can be advanced two-dimensionally and high-speed processing is possible. (Vertical and horizontal two-dimensional calculation filter). In addition, in the gradation value averaging process and edge detection (differentiation) process, when calculating the sum Σ of the gradation values (averaged gradation values) of a plurality of pixels arranged, the window W In addition to adding the gray value (average gray value) of the pixels that entered by moving the image to the previous total sum Σ, subtracting the gray value (average gray value) of the pixels that came out by moving the window W from the previous total value Σ As a result, it is possible to increase the speed of the averaging process and the edge detection process. In particular, the greater the number of gray values (average gray values) to be averaged (the number of pixels to be calculated), the greater the effect.

  Further, the conditions (scanning direction, threshold level, etc.) for detecting the edge lines E21, E22 of the film layer image portions I21, I22 are also determined by the processing unit 200 in the images in the inspection areas Z1, Z2 and the reference detection area Z0. The status can be scanned and set automatically based on the result. For example, the processing unit 200 can detect the edge line position (vertical position) based on the set threshold level while setting the threshold level at each angular position (θi).

  In this case, for example, the processing unit 200 scans the differential image (waveform) from the lower limit position to the upper limit position (or from the upper limit position to the lower limit position) of the inspection area at each angular position (θi), and the position of the peak value. (Vertical position) is detected, and a threshold level of a predetermined ratio (for example, 70%) of the peak value is set. Then, the processing unit 100 determines the center point of the width of the differential image (waveform) sliced at the threshold level as the edge line position (vertical position).

  As described above, since the threshold level is set based on the peak value of the differential waveform for each angular position (θi) and the edge line position is detected based on the set threshold level, the entire captured image I is detected. Even if the actual light / dark state changes partially, the edge line position can be detected based on the threshold level corresponding to the light / dark state, so that the edge line position can be detected with high accuracy. It becomes like this.

  As described above, the disk-shaped substrate inspection apparatus according to the present invention performs more efficient processing without sacrificing accuracy when inspecting the state of the film layer formed on the surface of the disk-shaped substrate. It is useful as an inspection apparatus that can evaluate the formation state of the film layer of a disk-shaped substrate such as a semiconductor wafer having a film layer formed on the surface.

It is a figure which shows typically the principal part of the imaging | photography system in the surface inspection apparatus of the semiconductor wafer as a disk-shaped board | substrate inspection apparatus which concerns on embodiment of this invention. It is a top view which shows the arrangement | positioning relationship of the camera unit with respect to a semiconductor wafer. It is sectional drawing which shows the example of the film layer formed in the surface of a semiconductor wafer. It is a block diagram which shows typically the principal part of the processing system in the surface inspection apparatus of the semiconductor wafer as a disk-shaped board | substrate inspection apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the process performed by the processing unit in the processing system shown in FIG. It is a flowchart which shows the 1st specific example of the edge line detection process of the film layer image part in the process shown in FIG. It is a flowchart which shows the 1st specific example of the evaluation information generation process in the process shown in FIG. It is a figure which shows an example of a picked-up image. It is a figure which shows the example by which the test | inspection area was set on the picked-up image. FIG. 10 is a diagram individually showing inspection areas (a) and (b) and a reference detection area (c) shown in FIG. 9. It is a figure which shows the principle of the process for detecting the edge line of a film layer image. It is a figure which shows the example by which the test | inspection area was set on the picked-up image of the state which the edge line of the film layer image part meandered largely. It is a figure which shows individually the test | inspection area shown in FIG. It is a flowchart which shows the 2nd specific example of the edge line detection process of the film layer image part in the process shown in FIG. It is a flowchart which shows the 2nd specific example of the evaluation information generation process in the process shown in FIG. It is a figure which shows the example in which the test | inspection area containing an allowance area was set on the picked-up image. It is a figure which shows individually test | inspection area (a) and (b) containing the tolerance | permissible area shown in FIG. It is a flowchart (the 1) which shows the 3rd specific example of the evaluation information generation process in the process shown in FIG. It is a flowchart (the 2) which shows the 3rd example of the evaluation information generation process in the process shown in FIG. It is a figure which shows the example which has the image part corresponding to a defect in an inspection area. It is a figure showing the technique principle of the automatic setting of an inspection area. It is a figure which shows the window used for the averaging (integration) process in the circumferential direction of a picked-up image, and an edge detection (differentiation) process. It is a figure which shows the specific example of the window shown in FIG. It is a figure which shows the state which shifted the window by 1 pixel in the vertical direction. It is a figure which shows the state which shifted the window further 1 pixel in the vertical direction. It is a figure which shows the state which shifted the window by 1 pixel in the horizontal direction.

Explanation of symbols

10 Semiconductor wafer (disc-shaped substrate)
10e Wafer outer periphery 21 First film layer 21e First film layer outer periphery 22 Second film layer 22e Second film layer outer periphery 100 Stage 110 Rotation drive motor 110a Rotating shaft 130 Camera unit 200 Processing unit 210 Operation unit 220 Display unit

Claims (10)

An inspection apparatus for a disk-shaped substrate having a film layer formed on a surface thereof,
An imaging unit that sequentially images the surface of the disk-shaped substrate on which the film layer is formed in the circumferential direction of the disk-shaped substrate and outputs an image signal;
An image processing unit that processes image signals sequentially output from the photographing unit;
The image processing unit
Image data generating means for generating photographed image data representing a photographed image extending from the image signal corresponding to the circumferential direction of the disk-shaped substrate;
Display control means for displaying the photographed image on a display unit based on the photographed image data;
Inspection area setting means for setting an inspection area extending corresponding to the circumferential direction on the photographed image displayed on the display unit;
An edge line of a film layer image portion corresponding to the film layer in the inspection area on the captured image is detected from the captured image data, and at each position in the circumferential direction of the edge line in the inspection area. Area intima layer edge position detecting means for generating in-area longitudinal position information representing a longitudinal position that is a position in a direction across the circumferential direction of
Vertical position information in the area, inspection area vertical position information indicating the vertical position of each position in the circumferential direction on the captured image of the inspection area, and a reference determined in the captured image The circumferential direction of the edge line of the film layer image portion on the captured image based on the reference portion based on reference vertical position information representing the vertical position at each position in the circumferential direction of the portion Film layer edge position information generating means for generating film layer edge position information representing the vertical position at each position;
A disk-shaped substrate inspection apparatus comprising: evaluation information generating means for generating evaluation information on the film layer formed on the surface of the disk-shaped substrate based on the film layer edge position information. The reference portion is an edge line of a surface image portion of the disk-shaped substrate on the photographed image,
The disk-shaped substrate inspection apparatus according to claim 1, wherein information on a vertical position at each position in the circumferential direction of an edge line of a surface image portion of the disk-shaped substrate on the photographed image is used as the reference vertical position information. .   3. The disk-shaped substrate inspection apparatus according to claim 1, wherein the inspection area setting means sets the inspection area in accordance with a predetermined setting operation by an operation unit. The area intima layer edge position detecting means scans an image in the inspection area in a direction crossing the circumferential direction at each position in the circumferential direction, and according to a predetermined condition, the film layer image portion on each scanning line Which detects the edge line of
4. The disk-shaped substrate inspection apparatus according to claim 1, wherein the condition for detecting the edge line is variable. 5. The disk-shaped substrate inspection apparatus according to claim 4, wherein the area intima layer edge position detecting means variably sets the condition for detecting the edge line according to a predetermined setting operation by the operation unit. An area departure determining means for determining whether an edge line of the film layer image portion has deviated from the inspection area;
6. The disk-shaped substrate inspection apparatus according to claim 1, wherein the evaluation information generation unit generates evaluation information based on a determination result by the area deviation determination unit. In the inspection area, a permissible area setting means for setting a permissible area extending corresponding to the circumferential direction;
An allowable area deviation determining means for determining whether an edge line of the film layer image part deviates from the allowable area;
The disk-shaped substrate inspection apparatus according to claim 1, wherein the evaluation information generation unit generates evaluation information based on a determination result by the allowable area deviation determination unit.   8. The disk-shaped substrate inspection apparatus according to claim 7, wherein the allowable area setting means sets the allowable area in accordance with a predetermined setting operation by the operation unit. When the permissible area deviation determining means determines that the edge line of the film layer image portion deviates from the permissible area, the permissible area deviates from the permissible area of the membrane layer image part. Means for determining whether or not film layer edge position information about the portion is obtained;
The evaluation information generation means determines that the film layer edge position information is obtained for a part of the edge line of the film layer image part that deviates from the permissible area. The disk-shaped substrate inspection apparatus according to claim 7 or 8, wherein the inspection information is used for generating the evaluation information. When the permissible area deviation determining means determines that the edge line of the film layer image portion has deviated from the allowable area, it deviates from the allowable area of the edge line of the film layer image portion. A part having a defect mask for determining whether or not the part is a part covered with a defect part formed on the surface of the disk-shaped substrate;
The disk-shaped substrate inspection apparatus according to claim 7, wherein the evaluation information generation unit generates evaluation information based on a determination result by the defect mask determination unit.

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