JP4755040B2 - Scratch inspection device, scratch inspection method - Google Patents

Description

  The present invention relates to a flaw inspection apparatus and method for inspecting the end face of a thin sample such as a semiconductor wafer, an aluminum substrate for a hard disk, a glass substrate, or the like.

In general, the end surface of a semiconductor wafer that is a disk-like thin piece (plate-like) is a curved surface (cross-sectional shape is almost semicircular or semielliptical) that bulges (projects) outward, and is glossy (light Is specularly reflected).
Such a semiconductor wafer (hereinafter referred to as a wafer) may be damaged or chipped when its end face (edge) comes into contact with other components or a wafer holding member during its manufacture or device manufacturing using the wafer. There is a case. Further, the wafer may be cracked due to the scratches or chips. For this reason, it is important to inspect whether or not there is a scratch on the end face of the wafer.
On the other hand, in Patent Document 1, coherent light is applied to an end portion (end surface) to be inspected arranged at a first focal position of an elliptical mirror, and light scattered and reflected by a scratch on the end portion to be inspected is secondly reflected by the elliptical mirror. There is shown a flaw inspection apparatus for inspecting the presence or absence of a flaw at an end portion to be inspected by detecting with a photodetector arranged at a focal position. In addition, in the mirror surface (inner surface) of the elliptical mirror shown in Patent Document 1, the region where the specularly reflected light (reflected light from the part having no flaw) from the end to be inspected reaches the light absorbing member ( Masking tape is affixed. In such a flaw inspection apparatus, when there is no flaw at the end to be inspected, the light regularly reflected at the end to be inspected is absorbed by the light absorbing member, and the reflected light hardly reaches the photodetector. On the other hand, when there is a scratch at the end to be inspected, the light irregularly reflected at the scratched portion is condensed on the photodetector by the elliptical mirror. As a result, it is possible to determine the presence or absence of scratches at the end portion to be inspected based on the light intensity detected by the photodetector.
Japanese Patent Laid-Open No. 2003-287412

However, the elliptical mirror that constitutes the flaw inspection apparatus shown in Patent Document 1 has a complicated three-dimensional shape, and a light absorbing member is affixed to an appropriate position on the inner surface, and is designed with high dimensional accuracy. And manufacturing (three-dimensional processing) is required. For this reason, there has been a problem that the labor and cost of designing and manufacturing the apparatus are large. In addition, it is necessary to position the positional relationship of the apparatus with high accuracy so that the end portion (sample) and the photodetector are correctly arranged at the focal position of the elliptical mirror, which increases the labor and cost required for the positioning mechanism. There was also a problem.
Accordingly, the present invention has been made in view of the above circumstances, and the object of the present invention is to use an apparatus that can be easily manufactured by a combination of existing parts, etc., and an end face of a thin sample (plate-like sample) such as a semiconductor wafer. It is an object of the present invention to provide a scratch inspection apparatus and method capable of automatically inspecting the presence or absence of a scratch on the surface.

In order to achieve the above object, the present invention provides an end to be inspected which is a glossy end surface (may be referred to as a plate-like sample) of a thin sample such as a semiconductor wafer (may be referred to as a substantially mirror-like end surface). It is comprised as a wound inspection apparatus which test | inspects the presence or absence of the crack in a part, and is provided with the component shown to the following (1)-(6).
(1) A plurality of light sources that are arranged in one plane substantially orthogonal to the front and back surfaces of the thin sample and irradiate light from different directions to the end portion to be inspected.
(2) An imaging means for acquiring image data by imaging the end portion to be inspected from a predetermined direction.
(3) The switching control is performed so that the lighting states of the plurality of light sources are in a state where only some of the light sources that are adjacent to each other and are sequentially different from each other are turned on (hereinafter referred to as a partially lighting state). 1 light source control means.
(4) Based on the respective image data obtained by the imaging means in each of the partially lit states, for each of the light sources that are lit, the image formed by the specularly reflected light at the end of the inspection of the light A specularly reflected light area that is an image area is specified, and the specularly reflected light area and the identification information of the corresponding light source (lighting light source) are associated with each other and recorded in a predetermined storage means. Recording means.
(5) The switching control is performed so that the lighting states of the plurality of light sources are in a state in which only some of the light sources that are adjacent to each other and that are sequentially different from each other are turned off (hereinafter, referred to as a partially turned off state). 2 light source control means.
(6) For each of the image data obtained by the imaging means in each of the partially turned off states performed following the partially turned on state, in an image region other than the regular reflection region corresponding to all the light sources that are turned on. By determining whether or not an image having a predetermined luminance or higher exists within a region of interest that is a part or all of a region overlapping with the regular reflection region corresponding to the light source that is turned off. A flaw discriminating means for discriminating the presence or absence of a flaw at the inspection end.
Here, a typical example of the thin sample is a substantially disk-shaped semiconductor wafer.
In addition, the specular reflection light area specifying / recording unit specifies, as the specular reflection light area, an area formed by pixels from which luminance values in image data protrude, for example.
Note that the partially lit state and the partially unlit state are similar states from the viewpoint that some of the light sources are lit and some of the other light sources are unlit. However, in the present application, the partially lit state means a state in which most of the plurality of light sources are turned off (very few are turned on), and the partially turned off state is a plurality of light sources. It is assumed that most of them are lit (a very small part is not lit).

In the scratch inspection apparatus having the above-described configuration, the specularly reflected light region specifying / recording means causes the light to be specularly reflected at the end portion to be inspected for each light source (light reflected from a portion having no scratch). A region (region on the image data) that reaches is specified as the regular reflection light region.
In the partially extinguished state, when there is no scratch at the end to be inspected, all of the reflected light of the light source that is lit is substantially specularly reflected. For this reason, the image of the reflected light does not appear in the region of interest, and the entire region is dark. On the other hand, when there is a scratch at the end to be inspected in the partially extinguished state, the light from the lighted light source (all the light that reaches the scratched portion) is irregularly reflected in various directions in the scratched portion. . For this reason, usually, an image of a part of the irregularly reflected light from the scratched part appears in the region of interest, and a part of the region of interest is bright. Therefore, it is possible to determine the presence or absence of a flaw at the end portion to be inspected based on whether or not an image (pixel or pixel group) having a predetermined luminance or higher exists in the region of interest.
In addition, in the region of interest, a relatively bright image formed by superimposing irregularly reflected light at the scratches relating to the light of all other light sources that are lit (all of the light that reaches the scratched part). Therefore, the image of diffusely reflected light in the region of interest can be detected with high sensitivity, and as a result, the presence or absence of a flaw on the end portion to be inspected can be reliably inspected.

Here, the control for setting the partially lit state is performed in order to identify the regular reflection light region corresponding to each light source. For this reason, it can be considered that the partially lit state is basically a state in which only one light source is lit.
On the other hand, when a state in which a plurality of light sources are simultaneously turned on is the partially lit state, an image obtained by the imaging unit includes a plurality of reflected light images corresponding to the light sources, and a plurality of the regular reflection lights. An area will be specified. Then, if it is possible to identify which of the plurality of light sources that are lit corresponding to each of the plurality of regular reflection light regions, the partially lit state may be a state in which the plurality of light sources are lit simultaneously. There is an advantage that there is no hindrance and the inspection speed is improved.
In general, the end portion to be inspected is a surface whose surface angle monotonously increases (or monotonously decreases) like the end face of a semiconductor wafer, and the angle difference in the direction seen from the end portion to be inspected is within a relatively small range. When there are a plurality of light sources, a plurality of the regular reflection light regions corresponding to the plurality of light sources overlap or are close to each other, and it is difficult to identify which light source corresponds to them. However, for a plurality of light sources that exist in a direction in which the angle difference between the directions viewed from the end to be inspected is relatively large, the plurality of specularly reflected light regions corresponding to the plurality of light sources are separated by a relatively large distance. It is easy to identify which light source they correspond to.
Accordingly, the partially lit state may be a state in which a plurality of light sources that are present in a direction in which the angle difference in the direction viewed from the end to be inspected is equal to or larger than a predetermined angle (a direction in which the angle difference is large) are lit simultaneously. It is done.

On the other hand, as described later, for a plurality of light sources having relatively close light irradiation angles with respect to the end portion to be inspected, when the specularly reflected light regions corresponding to them overlap, the partial light extinction state is changed to one light source. If only the area is turned off, there is no area that can be set as the area of interest, or there is only a very small area, and the area of interest (ROI) to be inspected for the wound is sufficiently large (wide). A situation that cannot be set.
In such a case, it is preferable that the partially extinguished state is a state in which all the plurality of light sources that exist within a range in which the angle difference in the direction viewed from the end portion to be inspected is within a predetermined angle are extinguished simultaneously.
As a result, a sufficiently large area of interest can be secured.
Further, it is conceivable that the plurality of light sources are arranged along, for example, a substantially arc centering on the arrangement position of the end portion to be inspected. Thereby, the distance from each light source to the to-be-inspected end becomes substantially equal, and by using the same light source for each light source, the irradiation intensity of the light from each light source to the to-be-inspected end can be made uniform. As a result, when performing image processing based on the image of reflected light from the end portion to be inspected (specification of the specularly reflected light region, etc.), there is no need to switch parameters (luminance threshold values, etc.) for each light source, Processing is simplified.
In addition, when a plurality of light sources are arranged so that the angle difference in the direction viewed from the end portion to be inspected is large (when the number of light sources is small), the overlap of the regular reflection light regions can be avoided, A portion where light is not irradiated is generated at the end portion to be inspected. As a result, the portion that is not irradiated with light cannot be inspected for scratches, causing a problem of inspection omission.

By the way, when a CCD camera or the like is used as the imaging unit, there is a limit to the imaging range (light receiving range) by one imaging unit. This limitation leads to a limitation on the maximum range of the surface angle of the end portion to be inspected (end surface of the thin sample) that can be inspected.
On the other hand, when the end portion to be inspected is viewed from the front direction so that the thin sample is in the vertical direction, the end portion to be inspected is imaged from two substantially symmetrical left and right directions to obtain image data. It is conceivable to provide the two imaging means to be acquired. For example, the two image pickup means pick up images of the end portion to be inspected from directions that are approximately 90 ° with the end portion to be inspected as a base point. In this case, the specularly reflected light area specifying / recording unit and the flaw determining unit execute processing on each of the image data obtained by the two imaging units.
Thereby, the maximum range of the surface angle at which the flaw inspection can be performed can be expanded beyond the limitation of the imaging range by one imaging means.
Further, when the two image pickup units are provided, the first light source control unit simultaneously turns on a plurality of light sources corresponding to the two image pickup units in the process of switching the partially lit state. Can be considered.
Similarly, it is also conceivable that the second light source control means simultaneously turns off a plurality of light sources corresponding to each of the two imaging means in the process of switching the partially turned off state.
Thereby, inspection time can be shortened.

Further, when performing a scratch inspection on a plurality of the end portions to be inspected, when the shapes of the end portions to be inspected are approximately equal and the positions of the end portions to be inspected with respect to the light source and the imaging means can be substantially constant In other words, the specularly reflected light regions corresponding to the respective light sources are substantially equal even if the inspected end portions are different.
Therefore, in such a case, the flaw inspection apparatus according to the present invention is obtained by the processing of the first light source control means and the specular reflection light area specifying / recording means executed for one of the inspected end portions. The information on the specularly reflected light area thus obtained may be used for the processing of the scratch determination means executed for each of the plurality of end portions to be inspected.
Thereby, when performing the inspection of the scratches on the plurality of inspected ends, the processing of the first light source control means and the specular reflection light area specifying / recording means is executed for each of the inspected ends. Compared with, inspection time can be further shortened.
In this case, in the image data obtained in the partially extinguished state, a part of the entire image area other than the regular reflection area corresponding to all the light sources that are lit (including an edge part). It is particularly preferable that the region to be excluded is the region of interest.
This is because such a region of interest is a region where the influence of the variation can be ignored even if there is some variation in the shape of each end to be inspected and the position of each end to be inspected with respect to the light source and the imaging means. .

On the other hand, the present invention can also be regarded as a scratch inspection method corresponding to the inspection method using the above-described scratch inspection apparatus.
That is, it is a flaw inspection method for inspecting the presence or absence of a flaw on the end portion to be inspected, which is the glossy end face of the thin sample, and includes the following steps (1) to (4).
(1) The lighting states of a plurality of light sources that are arranged in one plane substantially orthogonal to the front and back surfaces of the thin sample and irradiate light from different directions to the inspected end portions are partially adjacent to each other. A first light source control step in which switching control is performed by a predetermined control means so that only a part of the different light sources are sequentially turned on.
(2) For each piece of image data obtained in each of the partially lit states by an imaging means that captures image data from the predetermined direction to acquire image data, the edge portion to be inspected of the light source that is lit A specular reflection light area that is an image area of an image formed by specular reflection light at the light source is specified, and the specular reflection light area and the identification information of the corresponding light source are associated with each other and recorded in a predetermined storage unit. Reflected light area identification and recording process.
(3) Second switching control is performed by predetermined control means so that the lighting states of the plurality of light sources are in a partly light- off state in which only a part of light sources adjacent to each other and sequentially differing part of the light sources are turned off. Light source control process.
(4) For each of the image data obtained by the imaging means in each of the partially turned off states performed following the partially turned on state, in an image region other than the regular reflection region corresponding to all the light sources that are turned on. By determining whether or not an image having a predetermined luminance or higher exists within a region of interest that is a part or all of a region overlapping with the regular reflection region corresponding to the light source that is turned off. A scratch determination process for determining the presence or absence of a scratch at the inspection end.
By adopting such a flaw inspection method, the same effect as the flaw inspection apparatus can be obtained.

ADVANTAGE OF THE INVENTION According to this invention, the presence or absence of the damage | wound in the end surface of thin piece samples, such as a semiconductor wafer, can be test | inspected reliably.
Moreover, the flaw inspection apparatus according to the present invention is configured by a combination of a plurality of light sources, imaging means, and light source control means (combination of existing parts), and can be manufactured requiring complicated processing like the elliptical mirror. As a result, the flaw inspection apparatus according to the present invention can be manufactured relatively easily with reduced design effort and cost.
Furthermore, according to the present invention, the specularly reflected light region corresponding to each light source is specified by the specularly reflected light region specifying / recording means by using an actual thin sample, that is, by actual matching. It is not necessary to position each of the light source, the imaging means and the thin sample (semiconductor wafer, etc.) with high accuracy in advance. For this reason, the effort and cost regarding positioning of the apparatus which comprises an apparatus can also be held down.

Embodiments of the present invention will be described below with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.
Here, FIG. 1 is a schematic configuration diagram of a flaw inspection apparatus Z according to an embodiment of the present invention, FIG. 2 is a diagram showing definitions of a light irradiation angle and a surface angle, and FIG. 3 is a shape of an inspection end and a flaw inspection apparatus. FIG. 4 is a diagram showing an example (first example) of a first photographed image by the Z camera, and FIG. 4 is a diagram showing an example (second example) of the shape of the end to be inspected and the first photographed image by the camera of the wound inspection apparatus Z. FIG. 5 is a diagram illustrating an example of a binarized image of the first photographed image by the wound inspection apparatus Z, and FIG. 6 is a logical sum image based on the binarized images of the plurality of first photographed images by the wound inspection apparatus Z. FIG. 7 is a diagram illustrating an example of a second photographed image by the camera of the wound inspection apparatus Z, FIG. 8 is a flowchart illustrating a procedure of inspection processing by the wound inspection apparatus Z, and FIG. It is a figure showing schematic structure of flaw inspection apparatus Z 'which is an application example of.

First, the configuration of the flaw inspection apparatus Z according to the embodiment of the present invention will be described with reference to FIG. The flaw inspection apparatus Z is an apparatus that inspects whether or not a flaw exists on an end surface of a semiconductor wafer 1 (hereinafter referred to as a wafer) which is an example of a thin sample (which may be referred to as a plate-shaped sample). Here, the wafer 1 has a substantially circular plate shape (disk shape), and its end surface bulges outward and has a curved shape. 1A is a plan view (partial block diagram) of the scratch inspection apparatus Z, and FIG. 1B is a side view of the scratch inspection apparatus Z (partially omitted).
Hereinafter, the end face of the wafer 1 to be inspected for scratches is referred to as an inspected end portion P.
As shown in FIG. 1, the scratch inspection apparatus Z includes a light irradiation device 10, a camera 20, a computer 30 such as a personal computer, and a support mechanism 40 that supports the wafer 1.
The light irradiation device 10 is configured as an electronic circuit board, and a plurality of LEDs 12 that are point light sources for irradiating the wafer 1 with light and an LED drive circuit 11 for switching the blinking of each of the LEDs 12 are mounted on the electronic circuit board. Has been. In FIG. 1B, the description of some of the LEDs 12 is omitted.
Here, a predetermined position in a substantially central portion when the light irradiation device 10 (electronic circuit board) is viewed in plan is referred to as a reference position Q.

Here, the support mechanism 40 supports the wafer 1 so as to be rotatable in the circumferential direction. The support mechanism 40 is in contact with the two support portions 41 that support the end surface of the wafer 1 from below and the front and back surfaces of the wafer 1, thereby restricting the inclination of the wafer 1 (holding the posture) 42. And. Here, the two support portions 41 are configured by rollers that are driven to rotate by reducing a motor (not shown). And these two support parts 41 (roller) rotate, and the wafer 1 rotates to the circumferential direction. The operation of the drive sources (motors) of these two support portions 41 is controlled by the computer 30.
On the other hand, the guide portion 42 is constituted by a roller that rotates following the rotation of the wafer 1.

In the electronic circuit board constituting the light irradiation device 10, a notch 13 into which the wafer 1 is inserted is formed so that the inspection end portion P of the wafer 1 can be arranged at the reference position Q. That is, the reference position Q is the arrangement position of the inspection end portion P. Moreover, the to-be-inspected end part P can be easily changed by rotating the wafer 1 in the circumferential direction. Thereby, the presence or absence of a flaw can be inspected using the entire periphery of the wafer 1 or a plurality of end faces in the entire periphery as the inspection end portion P.
The plurality of LEDs 12 included in the light irradiation device 10 are such that the light emitting portions thereof are planes substantially orthogonal to the front and back surfaces of the wafer 1 and are located in one plane including the reference position Q, and the reference position It is mounted on the electronic circuit board so as to be located (along the arc) on an arc centered on Q. Here, the LEDs 12 are arranged at equal intervals (equal angular intervals) so that the directions viewed from the reference position Q are different by about 2 °, for example, except for the position where they interfere with the camera 20. In addition, the distance from the reference position Q (inspected end portion P) of each LED 12 is a sufficiently long distance (for example, about 150 mm) with respect to the depth dimension of the inspected end portion P. In addition, when the end surface of a thin piece sample is a semi-elliptical curved surface etc., it is possible to arrange | position each LED12 along the curve showing a shape substantially similar to the shape of the cross section of the thickness direction.
Further, the surface of the wafer 1 (the front surface and the back surface) is substantially orthogonal to one plane on which the light emitting portions of the LEDs 12 are arranged, and the center portion of the front and back surfaces of the wafer 1 (of the disk). The center) is inserted into the cutout portion 13 in a state where the light emitting portion of the LED 12 is positioned in one plane, and the inspection is performed in that state.
In accordance with a control command from the computer 30, the LED drive circuit 11 can individually blink the plurality of LEDs 12 arranged at each of a plurality of positions in one plane. In this way, each LED 12 (light source) of the light irradiation device 10 irradiates light at different irradiation angles with respect to the inspection end portion P of the wafer 1 disposed at the reference position Q.
The end surface (side surface) that is the end portion P to be inspected of the wafer 1 is processed smoothly and has a mirror surface or a glossy surface close to it. For this reason, as long as the to-be-inspected end P is not scratched, the light output from the LED 12 is substantially regularly reflected at the to-be-inspected end P and hardly diffusely reflected.

The camera 20 (digital camera) is fixed at a position (for example, about 50 mm to 100 mm) spaced from the reference position Q, receives reflected light from the inspection end portion P of the wafer 1 and photoelectrically converts it. , Two-dimensional luminance distribution data (that is, image data) of reflected light is acquired (an example of an imaging unit).
The camera 20 is disposed in one plane (a plane including the reference position Q) on which the light emitting unit of the LED 12 is disposed, and the front direction thereof is set toward the center of the surface of the wafer 1. That is, the camera 20 is installed so that the front direction thereof is a direction along a plane cross section at the center of the thickness direction of the wafer 1 (so that the wafer 1 is viewed from the side). As a result, the camera 20 can observe the inspected end portion P (end surface) of the wafer 1 over the entire thickness direction of the wafer 1.
Further, the focus of the camera 20 is set at the reference position Q (that is, the inspection end portion P).
The computer 30 controls the LED drive circuit 11 and the support mechanism 40 in the light irradiation device 10 (flashing control of the LED 12), and controls the shutter of the camera 20 and captures a captured image by the camera 20. The specific operation will be described later. Here, although not shown in FIG. 1, the computer 30 includes an interface for transmitting and receiving signals and acquiring image data with the LED drive circuit 11, the camera 20, and the support mechanism 40.
The processing of the computer 30 shown below is realized by the MPU included in the computer 30 executing a program stored in advance in a storage unit such as a hard disk drive included in the computer 30.

Here, with reference to FIG. 2, reference numerals representing the light irradiation direction and the like will be described. 2A is a diagram schematically illustrating a state in which the wound inspection apparatus Z is viewed in plan, and FIG. 2B is a diagram illustrating an enlarged portion of the reference position P. .
As shown in FIG. 2, the light irradiation angle when the direction of a straight line connecting the inspected end portion P and the camera 20 (hereinafter referred to as the camera front direction) is used as a reference is φ. In addition, a surface orthogonal to the camera front direction at the center position Px of the portion where the light is regularly reflected at the inspected end portion P (hereinafter referred to as an XY plane in the sense of a surface corresponding to the XY plane in the captured image). ) Is the surface angle with reference to.
Hereinafter, a state in which light is applied to the end portion P to be inspected by only one LED 12 is referred to as a single lighting state (an example of a partial lighting state). In addition, an image obtained by the camera 20 in the single lighting state is referred to as a first captured image, and the image data thereof is referred to as first image data.

Next, the principle of the flaw inspection of the end portion P to be inspected by the flaw inspection apparatus Z will be described.
In the wound inspection apparatus Z installed in the dark room, when light is irradiated to the inspection end portion P having no scratch, the light is regularly reflected at the inspection end portion P having gloss. The captured image by the camera 20 represents an image of the reflected light.
FIG. 3 is a view showing an example (a) of the shape of the end P to be inspected and an example (b) of the first photographed image by the camera 20 of the end P to be inspected. In FIG. 3B, the low luminance (dark) region is represented in black, and the light luminance (bright) region is represented in white.
FIG. 3A shows a shape of the end P to be inspected so that the surface angle θ increases monotonously (or monotonously decreases). The vertical direction in FIG. 3A is the thickness direction of the wafer 1.
When such an inspected end portion P is imaged by the camera 20 while irradiating light with only one LED 12, first image data of an image as shown in FIG. 3B is obtained.

In the first image data, the region Sx formed by the pixels having a relatively higher luminance value than the other (the luminance value protrudes) is almost equal to the light emitted from the lit LED 12 at the inspected end portion P. This is an image region (image region) formed by specularly reflected light (regularly reflected light). Hereinafter, the specularly reflected light image regions corresponding to the respective LEDs 12 are collectively referred to as a specularly reflected light region Sx.
For example, the computer 30 may be an image region composed of pixels having a predetermined luminance or higher in the first image data, or a spatial differential value of luminance (difference in luminance between adjacent pixels) may be equal to or higher than a predetermined value. An image region surrounded by the pixels is specified as a regular reflection light region Sx (a region where the luminance value protrudes).
The regular reflection light region Sx differs depending on the light irradiation direction of the LED 12 (the number of the LED 12 to be lit). That is, each LED 12 to be lit and the regular reflection light region Sx have a one-to-one correspondence. Hereinafter, the identification number (number in the order of arrangement) of each LED 12 is “i”, and the region of the image formed by the specularly reflected light of the i-th LED 12 is referred to as a specularly reflected light region Sx (i). The number of all LEDs 12 is n.

On the other hand, FIG. 4 is a diagram showing another example (a) of the shape of the end portion P to be inspected and an example (b) of the first photographed image by the camera 20 of the end portion P to be inspected.
FIG. 4A shows a measurement site P having a shape in which the end P to be inspected is recessed inward (hereinafter referred to as a recessed shape). The vertical direction in FIG. 4A is the thickness direction of the wafer 1.
When such an inspected end portion P is imaged by the camera 20 while irradiating light with only one LED 12, as shown in FIG. 4B, a plurality of specularly reflected light images (high luminance regions). Is obtained. This phenomenon occurs when there are a plurality of regular reflection positions Px having the same surface angle φ.
When the inspected end portion P has a shape as shown in FIG. 4A, except that the regular reflection region Sx corresponding to one LED 12 is constituted by a plurality of separated regions. There is no difference from the case of the inspected end portion P shown in FIG.
Therefore, if the wound inspection apparatus Z is used, it is possible to inspect the presence or absence of a scratch even when the inspected end portion P has a hollow shape.

Next, regarding the plurality of LEDs 12, consider the partially off state in which only some of the LEDs 12 are off (the other LEDs 12 are on). Hereinafter, an image obtained by the camera 20 in the partially unlit state is referred to as a second captured image, and the image data thereof is referred to as second image data.
FIG. 7 is a diagram illustrating an example of a second photographed image taken by the camera 20 in the case where there is no scratch on the inspected end portion P. Here, FIG. 7A shows an example in the case where there is no flaw in the inspected end portion P, and FIG. 7B shows an example in which there is a flaw in the inspected end portion P.
When there is no scratch on the end P to be inspected, as shown in FIG. 7A, in the second captured image, an image region other than the regular reflection region Sx corresponding to all the LEDs 12 that are lit (reflected light). If the region of interest Sy (ROI) is part or all of the region that overlaps with the regular reflection region Sx corresponding to the LED 12 being extinguished), the region of interest Sy is within the region of interest Sy. Does not show an image of reflected light.
On the other hand, when a scratch exists at the end P to be inspected, the light of the LED 12 that reaches the scratched portion is irregularly reflected in various directions at the scratched portion. For this reason, usually, as shown in FIG. 7B, in the second captured image, a partial image (pixels with high luminance) of irregularly reflected light from the scratched part also appears in the region of interest Sy. .
Therefore, it is possible to determine the presence or absence of a flaw in the inspected end portion P based on whether or not an image (pixel or pixel group) having a predetermined luminance or higher exists in the region of interest Sy.
In addition, in the region of interest Sy, the diffusely reflected light at the wound portion relating to the light of all other LEDs 12 that are lit (all of the light that reaches the wound portion) is relatively bright and formed. An image appears. For this reason, the image of the diffusely reflected light in the region of interest Sy can be detected with high sensitivity, and as a result, the presence or absence of a flaw on the end P to be inspected can be reliably inspected.

Next, a description will be given of what state the partial light-off state should be.
FIG. 5 shows the first picked-up image in the single lighting state in which each of the five LEDs 12 (i−2) to (i + 2) is lit, the specular reflection light region Sx (i), and other regions. An example of binarized images V (i−2) to V (i + 2) binarized into two. Here, since the LEDs 12 in the wound inspection apparatus Z shown in FIG. 1 are arranged in different directions by 2 degrees around the reference position Q (inspected end portion P), the numbers (i-2) to (i + 2) The numbered five LEDs 12 exist in a direction in which the angle difference in the direction viewed from the end P to be inspected (reference position Q) is within 8 ° (2 ° × 4).
When a large number of LEDs 12 (light sources) are arranged densely (here, in increments of 2 °) as in the scratch inspection apparatus Z shown in FIG. 1, the LEDs 12 to be lit are close to each other in the lighting state. The specularly reflected light region Sx partially overlaps. In the example shown in FIG. 5, at least a regular reflection region Sx when a certain LED 12 is turned on and a regular reflection region Sx when a neighboring LED 12 is turned on partially overlap each other.

On the other hand, FIG. 6 shows an example of a logical sum image (OR image) based on the binarized image in which the regular reflection light regions Sx overlap as shown in FIG.
Here, FIG. 6A is an example of an OR image obtained by performing a logical sum process on all binarized images (each pixel) other than the binarized image V (i). This corresponds to a binary image of an image obtained with only the i-th LED 12 (only one) turned off.
FIG. 6B is an example of an OR image obtained by performing a logical sum process on all binarized images (each pixel) other than the binarized images V (i−1) to V (i + 1). . This is because only the three consecutive LEDs 12 (i-1) to (i + 1) are turned off, that is, the angle difference in the direction viewed from the end P (reference position Q) to be inspected is 4 ° ( This corresponds to a binarized image of an image obtained in a state where all the LEDs 12 existing within a range of 2 ° × 2) are turned off simultaneously.
FIG. 6C is an example of an OR image obtained by performing a logical sum process on all binarized images (each pixel) other than the binarized images V (i−2) to V (i + 2). . In this state, only the five consecutive LEDs 12 (i-2) to (i + 2) are turned off, that is, the angle difference in the direction viewed from the end P (reference position Q) to be inspected is 8 ° ( This corresponds to a binarized image of an image obtained in a state where all the LEDs 12 existing within a range of 2 ° × 4) are simultaneously turned off.

When the LEDs 12 are densely arranged (when the regular reflection light regions Sx overlap), as shown in FIG. 6A, when only one LED 12 is turned off, the LED 12 (i-th LED being turned off) In the regular reflection region Sx (i) corresponding to (), an image of regular reflection light of another LED 12 whose light irradiation angle is relatively close appears. For this reason, it is an image area other than the regular reflection areas (Sx (1) to Sx (i-1), Sx (i + 1) to Sx (n)) corresponding to all the other LEDs 12 that are turned on and is turned off. A region overlapping with the regular reflection region Sx (i) corresponding to the LED 12 (a dark region where an image of reflected light does not appear) is not present (or only a very small region is present), and is subject to a scratch inspection. The region of interest Sy (ROI) cannot be set to a sufficient size (width).
On the other hand, as shown in FIGS. 6B and 6C, all the angle differences in the direction as viewed from the end P to be inspected (reference position Q) are within 4 ° or 8 °. When the LED 12 is turned off at the same time, it corresponds to an image region (a dark region where an image of reflected light does not appear) other than the regular reflection region Sx corresponding to all the other LEDs 12 that are turned on, and the LED 12 that is turned off. It is possible to sufficiently secure a region where the regular reflection region (for example, Sx (i)) overlaps (region that can be the region of interest Sy).
In the present embodiment, all the LEDs 12 that exist within a predetermined angle αs (for example, 4 ° or 8 °) within a range in which the angle difference seen from the end P (reference position Q) to be inspected is determined. With respect to the second image data obtained in the state of being turned off at the same time (an example of the partially turned off state), an image region (an image of reflected light appears) other than the regular reflection region Sx corresponding to all the other LEDs 12 that are turned on. A region in which the regular reflection region corresponding to the LED 12 located at the center when viewed from the end P to be inspected overlaps the region of interest Sy.
For example, when the set angle αs = 8 °, as shown in FIG. 6C, an image obtained when only the five consecutive LEDs 12 (i-2) to (i + 2) are turned off. Regarding the data, the image area (dark area where the reflected light image does not appear) other than the regular reflection area Sx corresponding to all other LEDs 12 that are lit, and the regular reflection area (Sx corresponding to the i-th LED 12 that is not lit) A region where (i)) overlaps is defined as a region of interest Sy (i). In this case, as shown in FIG. 6C, in the second image data obtained in the partially extinguished state, regular reflection corresponding to all the LEDs 12 (i-2) to (i + 2) that are turned on. Of the entire image area other than the areas Sx (i−2) to Sx (i + 2), a part of the area including the center (area excluding the edge) becomes the area of interest Sy (i).

Next, an inspection procedure of the inspection end portion P of the wafer 1 by the scratch inspection apparatus Z will be described with reference to the flowchart shown in FIG. Hereinafter, S1, S2,... Represent identification codes of processing procedures (steps). It is assumed that the processing shown in FIG. 8 is started in a state where the inspection end portion P of the wafer 1 is disposed at the reference position Q.
[Steps S1 to S6]
First, the computer 30 initializes a number i for identifying each LED 12 (i = 1) (S1).
Then, the computer 30 controls the LED drive circuit 11 to turn on the i-th LED 12 (S2), and the imaging of the end P to be inspected by the camera 20 in the lighting state (the one lighting state) (shutter ON). Then, recording (S3) of the captured image data (the first image data) is performed. An image captured by the camera 20 is recorded (stored) in a storage unit such as a hard disk included in the computer 30.
Further, the computer 30 performs an image processing calculation for specifying the regular reflection area Sx (i) corresponding to the lit-up i-th LED 12 based on the stored (acquired) first image data, and identifies the specified regular reflection area. Information representing Sx (i) and the corresponding LED 12 number (light source identification information) are associated with each other and recorded in storage means such as a hard disk (S4).
Then, the computer 30 sequentially increments the number i (S6), and determines that the lighting, imaging, and specular reflection area Sx identification and recording of all the LEDs 12 have been completed (S5). Repeat the process.
Thus, the computer 30 changes the lighting state of the plurality of LEDs 12 (point light sources) to the one lighting state (an example of the partial lighting state) in which only a part (here, one) of the LEDs 12 are sequentially lit. (S1, S2, S6: first light source control means and an example of the process).
Further, the computer 30 calculates the specular reflection region Sx (at the end P to be inspected) for each LED 12 that is lit based on the image data (first image data) obtained by the camera 20 in each of the one lighting state. The image region of the image formed by the regular reflection light) is specified, and the regular reflection light region Sx and the number (identification information) of the LED 12 corresponding thereto are associated and recorded in the storage means (S4: regular reflection). Example of optical region specifying / recording means and its process).

Next, the computer 30 displays a pattern (hereinafter referred to as an LED extinguishing pattern) indicating how the LED 12 is extinguished to make the partial extinguishing state in what combination, and the region of interest (ROI) corresponding to each of the LED extinguishing patterns. ) Is set (S7).
Here, as described above, the computer 30 has all of the angle differences in the direction viewed from the inspected end portion P (reference position Q) within a predetermined set angle αs (for example, 8 °). N types of LED turn-off patterns are set so that the state where the LEDs 12 are turned off at the same time becomes the partially turned off state. For each of the n LEDs 12, the LEDs 12 that are present within a range of ± (αs / 2) ° centering on the direction in which the LED 12 exists (direction viewed from the end portion P to be inspected) are turned off simultaneously. n types of LED extinguishing patterns up to n-th are set.
Further, the computer 30 sets the regular reflection region Sx (i) corresponding to the i-th LED 12 as the region of interest Sy (i) corresponding to the i-th LED turn-off pattern. As a result, each region of interest Sy is an image region other than the regular reflection region Sx corresponding to all the other LEDs 12 that are lit (images of reflected light are present) in the second image data obtained in the partially unlit state. A dark region that does not appear) and a part or all of a region in which the regular reflection region corresponding to the LED 12 located at the center when viewed from the inspected end portion P of the unlit LED 12 overlaps (FIG. 6B). FIG. 6 (c) and FIG. 7).
Here, an example is shown in which the computer 30 automatically sets the LED extinguishing pattern based on the set angle αs. However, it is considered that the LED extinguishing pattern is preset by information input by a user or the like. It is done.

[Steps S8 to S13]
Next, the computer 30 executes a process of steps S8 to S17 described below, thereby executing a scratch inspection process for the inspected end portion P of the wafer 1.
First, the computer 30 initializes a number j (j = 1) for identifying each LED turn-off pattern (S8).
Next, the computer 30 controls the LED drive circuit 11 to set the lighting state of the LED 12 to a state according to the j-th LED turning-off pattern (S9). Further, the computer 30 performs imaging (shutter ON) of the inspection end portion P by the camera 20 and recording of the captured image data (second image data) in the LED extinguishing pattern (the partially extinguished state) (S10). An image captured by the camera 20 is recorded (stored) in a storage unit such as a hard disk included in the computer 30.
Next, the computer 30 sets a predetermined setting in the region of interest Sy (j) corresponding to the LED turn-off pattern at that time for the second image data obtained with the j-th LED turn-off pattern. By determining whether or not an image (pixel) having a luminance or higher is present, it is determined whether or not there is a scratch on the inspected end P (S11: an example of a scratch determination unit and its process).
Furthermore, the computer 30 sequentially increments the number j (S13) unless it is determined in step S11 that an image (pixel) having a luminance equal to or higher than the set luminance exists (a flaw exists) in the region of interest Sy (j). However, the processes in steps S9 to S13 are repeated until it is determined (S12) that the processes for all the LED turn-off patterns have been completed.
In this way, the computer 30 performs switching control so that the lighting states of the plurality of LEDs 12 are changed to the partially extinguished state in which only some of the different light sources are sequentially turned off (S8 to 10, S13: second light source control). Examples of means and steps thereof).
Further, the computer 30 determines whether or not there is an image of the set luminance or more in the corresponding region of interest Sy for each of the second image data obtained by the camera 20 in each of the partially off states. Is used to determine the presence or absence of scratches at the end P to be inspected (S11: scratch determination means and an example of the process).

[Steps S14 to S17]
When the computer 30 determines in step S11 that an image (pixel) having a luminance equal to or higher than the set luminance exists in the region of interest Sy (j) during the processing of steps S9 to S13, the end portion to be inspected An output indicating that there is a scratch on P, for example, a message output or a voice output to the display unit, or a predetermined error signal is output (S14), and the scratch inspection process for the wafer 1 is terminated.
On the other hand, if no high-luminance pixel is found in the region of interest Sy for all the LED extinguishing patterns (no flaws are present), the computer 30 is in a state that satisfies a predetermined inspection end condition. Is determined (S15).
Here, when the computer 30 determines that the inspection end condition is not satisfied, the computer 30 changes the position of the inspected end portion P by controlling the support mechanism 40 and rotating the wafer 1 (S16), Then, the processes in steps S8 to S16 described above are repeated.
And the computer 30 is a case where during the processing of steps S8 to S16, in step S11, it has not been determined that an image (pixel) having the set luminance or higher exists in the region of interest Sy (j). In step S15, if it is determined that the inspection end condition is satisfied, an output indicating that there is no scratch on the inspected end portion P (message output to the display unit, etc.) is performed (S17). The scratch inspection process is terminated.

According to the flaw inspection apparatus Z that performs the processing described above, the end surface of the wafer 1 can be reliably and promptly inspected for the presence or absence of flaws at a plurality of end portions P in the circumferential direction.
Moreover, the flaw inspection apparatus Z is configured by a combination of a plurality of LEDs 12, a camera 20, and a computer 30 (control means) (combination of existing parts), and can be manufactured that requires complicated processing like the elliptical mirror. As a result, the flaw inspection apparatus Z can be manufactured relatively easily with reduced design and manufacturing effort and cost.
Further, according to the scratch inspection apparatus Z, the specularly reflected light region Sx corresponding to each of the LEDs 12 is specified by using the actual wafer 1, that is, by actual matching, by the processing of steps S1 to S6. For this reason, it is not necessary to position each of the plurality of LEDs 12, the camera 20, and the wafer 1 with high accuracy in advance. For this reason, the effort and cost regarding positioning of the apparatus which comprises an apparatus can also be held down.

Here, the relative position of the support mechanism 40, the LED 12, and the camera 20 is positioned so that the inspected end portion P, which is one place on the end face, is located at the reference position Q for the wafer 1 to be inspected. Consider a case (a state in which preparations for starting the processing of steps S1 to S17 are completed).
In this case, even after the wafer 1 is rotated by the support mechanism 40 and the end portion P to be inspected is changed (S16), if the shapes of the end faces of the wafer 1 are substantially equal (if the same type of wafer 1 is used). ), The regular reflection light region Sx corresponding to each of the LEDs 12 is substantially the same even if the inspected end portion P is different.
Therefore, in the flaw inspection process (FIG. 8) by the flaw inspection apparatus Z, the processing of steps S1 to S6 executed for one inspection end P (the first light source control means and the specular reflection light area identification / recording). Scratch discrimination processing (S11: Scratch discrimination) in which the information of the regularly reflected light region Sx (information recorded in step S4) obtained by the processing of the means is executed for each of the plurality of end portions P to be inspected. It is configured to be used for an example of processing of means.
Thereby, when performing the test | inspection of the damage | wound about several to-be-inspected edge part P, compared with the case where the process of step S1-S6 is performed about each of several to-be-tested edge part P, inspection time can be shortened more.
Of course, the results of the processing in steps S1 to S6 (information about the specular reflection light region Sx) performed on the inspection end portion P of a certain wafer 1 are used as the scratches executed on a plurality of inspection end portions P of other wafers 1. You may make it use for a discrimination | determination process (S11: An example of a process of a damage | wound discrimination | determination means).

[Scratch inspection device Z '(application example)]
Next, a wound inspection apparatus Z ′, which is an application example of the wound inspection apparatus Z, will be described with reference to FIG. Hereinafter, only the difference between the scratch inspection apparatus Z described above and the scratch inspection apparatus Z will be described. In FIG. 9, the same components as those shown in FIG. 1 are denoted by the same reference numerals.
As shown in FIG. 9, the wound inspection apparatus Z ′ includes two cameras 20R and 20L as the camera 20 that captures an image of reflected light from the inspected end P, and these are provided in the inspected end P. They are arranged in different directions. Hereinafter, they are referred to as a first camera 20R and a second camera 20L, respectively.
Further, the flaw inspection apparatus Z ′ includes a computer 30 ′ that is different from the computer 30 described above and that has a part of the program to be executed.

In the example shown in FIG. 9, when the two cameras 20R and 20L are viewed from the front direction of the inspected end portion P so that the wafer 1 (thin sample) is in the vertical direction, the inspected end portion P Is imaged from each of two symmetrical left and right directions to obtain image data.
The two cameras 20R and 20L are arranged in a direction that forms 90 ° with respect to the reference position Q (that is, the end portion P to be inspected) (direction of ± 45 ° with respect to the surface direction of the wafer 1). Yes. Thereby, each of the cameras 20R and 20L detects the brightness of the reflected light reflected in a part of the entire region (entire surface) of the end portion P to be inspected (region visible from each arrangement position).
Then, the computer 30 ′ performs processing (specific specular light region identification and processing) for each of the image data (the first image data and the second image data) obtained by two cameras in steps S4 and S11 shown in FIG. Recording process and scratch determination process).

Further, the computer 30 ′ switches the plurality of LEDs 12 corresponding to each of the two cameras 20 </ b> R and 20 </ b> L in the process of sequentially switching the plurality of LEDs 12 through the LED driving circuit 11 and lighting them (the process of switching the partial lighting state). Control is performed so that the lights are turned on simultaneously (an example of the first light source control means).
As shown in FIG. 9, among a plurality of LEDs 12 arranged on a circular arc, a part of the LEDs 12R (for example, LED 12Ra) arranged on the opposite side to the second camera 20L with respect to the first camera 20R, The output light is blocked by the wafer 1 and does not reach the second camera 20L (an image is not detected).
Similarly, with respect to a part of the LED 12L (for example, the LED 12La) disposed on the opposite side to the first camera 20R with respect to the second camera 20L, the output light is blocked by the wafer 1 and the second camera 20L. Will not reach.
Therefore, the computer 30 ′, in the above-described step S2 (see FIG. 8), some of the LEDs (such as LED12Ra) corresponding to the first camera 20R and some of the LEDs (such as LED12La) corresponding to the second camera 20L. And the LED driving circuit 11 are controlled so as to light up simultaneously.
Similarly, in the process of switching the partially off state through the LED drive circuit 11 (step S8), the computer 30 ′ controls the plurality of LEDs 12 corresponding to the two cameras 20R and 20L to be turned off simultaneously (step S8). Example of second light source control means).
Thereby, inspection time can be shortened.
The flaw inspection apparatus Z ′ shown in FIG. 9 includes two cameras 20, but the same operation and effect can be obtained with a configuration including three or more cameras 20.

In the embodiment described above, the LED 12 that is a diffused light source is directly used as a light source (point light source). The reason why such a configuration can be adopted is that each LED 12 is arranged at a distance far enough compared to the size (depth length) of the end portion P to be inspected, and the light of each LED 12 is the end portion to be inspected. This is because P can be regarded as parallel light.
On the other hand, when a light source such as the LED 12 is disposed close to the inspection end P, it is desirable to irradiate the inspection end P with the light from the light source as parallel light using a lens.
In the above-described embodiment, the LED 12 is used as the light source. However, other types of light sources such as a laser diode, an incandescent bulb, and a fluorescent lamp may be used.
In the above-described embodiment, since the shape of the end face of the wafer 1 is inspected over the entire thickness direction of the wafer 1, the camera 20 looks at the wafer 1 from the side (from the front of the inspected end portion P). Was set to. However, it is conceivable that the camera 20 is installed at a position and orientation different from those of the above-described embodiments according to the purpose.
In addition, according to the flaw inspection apparatuses Z and Z ′, the flaw inspection of the end face can be similarly performed on a thin sample such as an aluminum substrate or a glass substrate.

In the above-described embodiment, the configuration in which the reflected light from the end portion P to be inspected is directly incident on the camera 20 has been described. However, a configuration is also conceivable in which an optical device (such as a mirror) that changes the reflected light from the end P to be inspected is provided and the reflected light that has been changed by the optical device is incident on the camera 20. Thereby, when it is desired to detect reflected light in a direction along a plane on which the light source (LED 12) is arranged, interference between the camera 20 and the light source having a relatively large installation space can be avoided. Thereby, the range of a light irradiation angle can be expanded and the inspection range of the flaw in the to-be-inspected edge part P can be expanded more.
Further, the scratch inspection apparatus Z according to the above-described embodiment is intended to inspect a substantially circular plate-shaped (disk-shaped) wafer 1, but if the support mechanism is replaced, other shapes such as a rectangular plate shape may be used. It is also possible to use a thin piece sample as an inspection object.

In the above-described embodiment, the example in which the LEDs 12 (light sources) are arranged over a range close to 360 ° when viewed from the reference position Q (inspected end portion P) is shown. However, the present invention is not limited to this. Absent.
For example, the LEDs 12 (light sources) are arranged over a predetermined angular range (for example, a range of ± 90 °) on the left and right with the front direction of the end portion P to be inspected as the center when viewed from the reference position Q (the end portion to be inspected P). Such a configuration is also conceivable.
As a result, on the end face of the wafer 1 (the end face protruding outward), it is possible to inspect the scratch at least at the apex portion and its periphery where damage is most likely to occur.
The support mechanism 40 is not limited to the above-described configuration, and may be realized by other configurations such as a mechanism that supports and rotates the center position of the wafer 1 by suction.
In the above-described embodiment, the example in which the first image data is acquired as the single lighting state in which only one LED 12 is lit in step S2 (see FIG. 8) is not limited to this. .
For example, in the process in which the wound inspection apparatus Z shown in FIG. 1 executes the process of step S2, the angle in the direction when the lighting state (partial lighting state) of the LED 12 is viewed from the end portion P (reference position Q) to be inspected. It is also conceivable that two LEDs 12 present in a direction where the difference is equal to or larger than a predetermined angle (for example, about 200 °) are lit simultaneously. That is, among the plurality of LEDs 12, the specularly reflected light region Sx is separated by a relatively large distance, and it is easy to identify which LED 12 corresponds to them (the identification method is known). A plurality of lights are turned on simultaneously. For example, the 1st to nth LEDs 12 are arranged at positions whose angles around the inspected end P are different by 2 °, and when the predetermined angle is 200 °, (i + 100) ) The LED is turned on at the same time. In this case, in step S4, the computer 30 detects the two regular reflection light regions Sx corresponding to the two LEDs 12 that are simultaneously turned on. Further, the computer 30 identifies which of the two regularly-reflected light regions Sx detected corresponds to one of the two lit LEDs 12 depending on whether it is on the right side or the left side.

By the way, when using the light irradiation apparatus 10 that switches a plurality of light sources (the LEDs 12 in the above-described embodiment) and irradiates light to the end portion P to be inspected, the inspection of the reference position Q from each light source due to individual differences of each light source. Variations may occur in the amount of light (intensity) of the light irradiated to the end portion P. Therefore, it is important to adjust in advance so that the variation becomes as small as possible.
Specifically, when a photosensor is arranged at the reference position Q where the end P to be inspected is arranged, and each light source is sequentially switched and lit, the light intensity detected by the photosensor is at a substantially constant level. Then, the power (voltage or current) supplied to each light source, that is, the light emission amount (light emission intensity) of each light source is adjusted in advance.
For example, when the light source is an LED, a variable resistor is provided on the power supply line for each LED, and the supply current to each LED is adjusted in advance by adjusting the resistance value of this variable resistor. Alternatively, a pulse width modulation device that can control the power supply to each LED by pulse width modulation (PWM) is provided, and thereby the power supplied to each LED is adjusted in advance.
In addition, it is detected by the camera 20 when a reflecting member (mirror or the like) whose reflection direction or reflectance is known is arranged at the reference position Q where the end P to be inspected is arranged, and each light source is sequentially switched on. It is also conceivable that a light intensity correction coefficient for each light source is calculated and stored in advance based on variations in light intensity. At the time of actual inspection, the inspection is performed using the corrected measurement value (light intensity distribution) based on the correction coefficient.
By performing the adjustment as described above, it is possible to avoid the occurrence of inspection errors due to variations in the characteristics of the light source.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a scratch inspection apparatus for an end face of a thin sample such as an aluminum substrate or a glass substrate for a semiconductor wafer or hard disk.

The schematic block diagram of the wound inspection apparatus Z which concerns on embodiment of this invention. The figure showing the definition of a light irradiation angle and a surface angle. The figure showing the example (1st example) of the shape of the to-be-inspected edge part, and the 1st picked-up image by the camera of the wound inspection apparatus Z. The figure showing the example (2nd example) of the shape of a to-be-inspected edge part, and the 1st picked-up image by the camera of the wound inspection apparatus Z. The figure showing an example of the binarized image of the 1st picked-up image by the wound inspection apparatus Z. The figure showing an example of the logical sum image based on the binarized image of the some 1st picked-up image by the wound inspection apparatus Z. The figure showing the example of the 2nd picked-up image by the camera of the wound inspection apparatus Z. The flowchart showing the procedure of the inspection process by the wound inspection apparatus. The figure showing the schematic structure of the flaw inspection apparatus Z 'which is an application example of the flaw inspection apparatus Z.

Explanation of symbols

Z, Z '... Scratch inspection device 1 ... Wafer 10 ... Light irradiation device 11 ... LED drive circuit 12 ... LED
13 ... Notch 20 ... Camera 30, 30 '... Computer 40 ... Support mechanism

Claims (11)

A wound inspection apparatus for inspecting the presence or absence of scratches at the end portion to be inspected, which is the glossy end face of a thin sample,
A plurality of light sources arranged in a plane substantially orthogonal to the front and back surfaces of the thin sample, and irradiating light from different directions with respect to the end portion to be inspected,
Imaging means for capturing image data by capturing the inspected end from a predetermined direction;
First light source control means for performing switching control so that the lighting states of the plurality of light sources are partly light sources adjacent to each other and only different light sources are sequentially turned on;
Based on the image data obtained by the imaging means in each of the partially lit states, for each of the light sources that are lit, in the image area of the image formed by the specularly reflected light at the inspected end of the light A specularly reflected light area is specified, and the specularly reflected light area is specified and recorded in a predetermined storage means in association with the identification information of the light source corresponding to the specularly reflected light area;
A second light source control means for performing switching control so that a lighting state of the plurality of light sources is a partial light- off state in which only a part of light sources adjacent to each other and sequentially differing light sources are turned off;
With respect to each of the image data obtained by the imaging means in each of the partial light- off states performed following the partial light-on state, the image data other than the regular reflection regions corresponding to all the light sources that are lit are turned off. By determining whether or not an image having a predetermined luminance or higher is present in a region of interest that is a part or all of a region overlapping with the regular reflection region corresponding to the light source in the inside, scratches on the inspected end portion Scratch detection means for determining the presence or absence of,
A flaw inspection apparatus comprising: Wherein some lighting state, Ri state where only one light source is lit, or the state der the angular difference in the direction as viewed from the inspected end a plurality of light sources that are present in the direction of a predetermined angle or more are lit at the same time, 2. The flaw inspection apparatus according to claim 1, wherein the partial light extinction state is a state in which a plurality of light sources existing in a range in which an angle difference in a direction viewed from the end portion to be inspected is within a predetermined angle are extinguished simultaneously . The flaw inspection apparatus according to claim 1 or 2 , wherein the plurality of light sources are arranged along a substantially arc centering on an arrangement position of the end portion to be inspected. The flaw inspection according to any one of claims 1 to 3 , wherein the specular reflection light area specifying / recording unit specifies, as the specular reflection light area, an area formed by pixels having a luminance value protruding from image data. apparatus. When the end portion to be inspected is viewed from the front direction so that the thin sample is in the vertical direction, the end portion to be inspected is imaged from two substantially symmetrical left and right directions to obtain image data. Comprising the imaging means ;
The flaw inspection apparatus according to any one of claims 1 to 4 , wherein the specularly reflected light region specifying / recording unit and the flaw discriminating unit execute processing on each of the image data obtained by the two imaging units. The wound inspection apparatus according to claim 5 , wherein the two image pickup units are arranged such that their optical axes intersect each other at approximately 90 ° through the end portion to be inspected . The plurality of light sources correspond to the two imaging means so as to irradiate light from each of two substantially symmetrical directions on the left and right sides with respect to the inspected end portion. Composed of two light source groups arranged in
The first light source control means includes lighting states of a plurality of light sources included in each of the light source groups included in the two light source groups, disposed substantially symmetrically with respect to the end portion to be inspected, and adjacent to each other. Switching control is performed so that only a part of the two light sources that are sequentially different and the two light sources that are sequentially turned on are partially lit.
The second light source control means includes lighting states of a plurality of light sources included in each of the light source groups included in the two light source groups, disposed substantially symmetrically with respect to the end portion to be inspected, and adjacent to each other. Switching control is performed so that only a part of the two light sources that are sequentially different and only two light sources that are sequentially turned off are partially turned off .
The first light source control means is included in the two light source groups in the process of switching the lighting state of the light source in the partially lit state, and is disposed substantially symmetrically with respect to the end portion to be inspected. The wound inspection apparatus according to claim 5 or 6 , wherein a part of light sources adjacent to each other are turned on simultaneously . The second light source control means is included in the two light source groups in the process of switching the lighting state of the light source in the partially off state , and is disposed substantially symmetrically with respect to the end portion to be inspected. The wound inspection apparatus according to any one of claims 5 to 7 , wherein a part of light sources adjacent to each other are turned off simultaneously. The flaw inspection apparatus according to claim 1 , wherein the thin piece sample is a substantially disk-shaped semiconductor wafer . The information on the specularly reflected light area obtained by the processing of the first light source control means and the specularly reflected light area specifying / recording means executed for one of the inspected end parts includes a plurality of the inspected end parts. The flaw inspection apparatus according to any one of claims 1 to 9 , wherein the flaw inspection device is used for processing of the flaw discriminating means executed for each of the flaws. A scratch inspection method for inspecting the presence or absence of scratches at the end portion to be inspected, which is the glossy end surface of a thin sample ,
The lighting states of a plurality of light sources that are arranged in one plane substantially orthogonal to the front and back surfaces of the thin sample and irradiate light from different directions to the end portion to be inspected are a part of the light sources adjacent to each other. A first light source control step of performing switching control by a predetermined control means so that only a part of the different light sources are sequentially turned on ,
For each of the image data obtained in each of the partially lit states by the imaging means that captures the imaged edge from a predetermined direction and acquires image data, the light of the light source that is lit is positive at the edge to be inspected. A specular reflection light area that is an area of an image formed by reflected light is specified, and the specular reflection light area is specified and recorded in a predetermined storage unit in association with identification information of the corresponding light source.・ Recording process ,
Second light source control for performing switching control by a predetermined control means so that the lighting states of the plurality of light sources are in a partially extinguished state in which only some of the light sources adjacent to each other and sequentially differing light sources are extinguished. Process ,
With respect to each of the image data obtained by the imaging means in each of the partial light-off states performed following the partial light-on state, the image data other than the regular reflection regions corresponding to all the light sources that are lit are turned off. By determining whether or not an image having a predetermined luminance or higher is present in a region of interest that is a part or all of a region overlapping with the regular reflection region corresponding to the light source in the inside, scratches on the inspected end portion A scratch determination process for determining the presence or absence of
A scratch inspection method comprising:

Images