JP2008064656A - Peripheral edge inspecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a peripheral edge inspecting apparatus capable of minutely observing an edge portion, without making the apparatus large-sized. <P>SOLUTION: The apparatus comprises: a support member (rotary table 30) for supporting an object to be inspected (semiconductor wafer 10); an illuminating member (lamp 20, ring-light 27) for illuminating the peripheral edge (edge portion 11) of the object to be inspected; an observing member (CCD camera 21) for observing the peripheral edge of the object to be inspected; and a reflecting member (reflective mirror 22) for reflecting light which passes through an area near the peripheral edge, toward the observing member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a peripheral inspection apparatus for irradiating light to the edge portion and observing the edge portion in order to detect defects generated on the peripheral edge (edge portion) of an inspection object such as a semiconductor wafer or a liquid crystal glass substrate.

  The integration degree of each chip area formed on a semiconductor wafer is increasing year by year. Accompanying this, observation and inspection of defects generated at the edge portion of the semiconductor wafer, for example, defect of the edge portion, generation of foreign matters such as particles due to the defect, adhesion, and the like have become important. Such a defect in the edge portion extends to a chip region in the vicinity thereof and greatly affects the yield of the semiconductor chip.

  In the inspection and observation of the edge part, the illumination light is directed toward the edge part from the semiconductor wafer in order to obtain a good image of the edge part that is important not only for detecting foreign matter but also for understanding the defect state. It is necessary to shoot with irradiation.

  However, of the illumination light, what is actually involved in shooting is only light that irradiates the surface of the semiconductor wafer, reflects it, and returns to the shooting camera. Light that irradiates the edge portion is rounded. The light is scattered and it hardly returns to the camera side. For this reason, the image of the edge part acquired with the imaging camera is painted black, and the shape cannot be determined. In addition, some illumination light passes through the semiconductor wafer without hitting it, and therefore the periphery of the edge portion is assimilated with the edge portion and similarly painted black, and the edge portion cannot be extracted. .

For example, the light emitting part is formed in a belt-like shape and in an arc shape or an elliptical arc shape, and is equipped with a C-type light source that irradiates scattered light from the top and bottom and side directions on the edge portion of the silicon wafer placed on the rotary table. Surface defect detection equipped with a CCD camera for top surface shooting, side surface shooting, and bottom surface shooting that receives the reflected light of the light emitted from the C-type light source to the edge portion and images the top, side, and bottom surfaces of the edge portion. An apparatus has been proposed (Patent Document 1).
JP 2003-139523 A

  However, it requires a C-type light source that irradiates scattered light from the top and bottom and side surfaces of the edge portion, and a plurality of CCD cameras that receive reflected light from the edge portion of the light irradiated by the C-type light source. There was a problem that became a major issue.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a peripheral inspection apparatus capable of performing detailed observation of an edge portion without making the apparatus large.

  The peripheral inspection apparatus according to claim 1 of the present invention that achieves the above object is a support member that supports an inspection object, an illumination member that illuminates the peripheral edge of the inspection object, and an observation of the peripheral edge of the inspection object. And a reflecting member that reflects the light that has passed through the vicinity of the periphery toward the observation member.

  Examples of the inspection object include a semiconductor wafer such as a silicon wafer and a liquid crystal glass substrate.

  Examples of the support member include, but are not limited to, a rotary table on which the inspection object is placed.

  The observation unit includes, for example, a CCD camera, but is not limited to this, and a CMOS sensor can also be used.

  The reflection member includes, for example, a reflection mirror, but is not limited thereto, and a prism can also be used.

  The peripheral edge inspection apparatus according to claim 2 of the present invention is characterized in that the reflecting member is disposed at a position facing the illumination member with the inspection object interposed therebetween.

  The peripheral edge inspection apparatus according to claim 3 of the present invention is characterized in that the reflection member is configured such that an angle with respect to the peripheral edge and / or the observation member can be adjusted.

  The peripheral edge inspection apparatus according to claim 4 of the present invention is configured such that the illumination member has the illumination edge parallel to or inclined with respect to a direction (line) connecting the observation member and the periphery observed by the observation member. It is characterized by lighting.

  In the peripheral inspection apparatus according to claim 5 of the present invention, the observation member includes an image sensor, and the image output of the peripheral image captured by the image sensor is subjected to image processing to detect the shape and size of the peripheral defect. An image processing apparatus is provided.

  A peripheral edge inspection apparatus according to a sixth aspect of the present invention includes a defect position detection member that detects a defect position on a peripheral edge of the inspection object, and the support member includes a rotation mechanism that rotates the inspection object. The defect position detection device detects a defect position on the periphery of the inspection object while rotating the inspection object by the rotation mechanism.

  The peripheral edge inspection method according to claim 7 of the present invention is a method of rotating the inspection object, irradiating illumination light to the periphery of the inspection object, and photographing the periphery irradiated with the illumination light. And a step of reflecting the illumination light toward the image sensor during the photographing step.

  The peripheral edge inspection method according to claim 8 of the present invention further includes a step of detecting a defect position of the peripheral edge.

  According to the peripheral inspection apparatus of the present invention, since the reflection member that reflects the light that has passed through the vicinity of the periphery of the inspection object is reflected toward the observation member, the apparatus does not become large and detailed observation of the edge portion can be performed. .

  Hereinafter, an embodiment of a peripheral edge inspection apparatus according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic side view showing an embodiment of the peripheral edge inspection apparatus of the present invention, and FIG. 2 is a schematic side view showing a modification of the peripheral edge inspection apparatus of FIG.

  As shown in FIG. 1, the peripheral edge inspection apparatus includes a lamp 20 as an illumination member that illuminates an edge portion 11 of a semiconductor wafer 10 such as a silicon wafer placed on a rotary table 30 and a planar portion 12 in the vicinity thereof, A CCD camera 21 as an observation member for photographing the edge portion 11 and the plane portion 12 illuminated by the lamp 20 and a reflection member for reflecting the light of the lamp 20 that has passed near the edge portion 11 toward the CCD camera 21. Reflection mirror 22.

  The lamp 20 is composed of, for example, a halogen lamp, a white light emitting diode, or the like, and is disposed in a space orthogonal to the optical axis of the CCD camera 21 at a position above the surface of the semiconductor wafer 10. A half mirror 23 is disposed at the intersection of the center of the optical path of the lamp 20 and the optical axis of the CCD camera 21. The half mirror 23 reflects the illumination light from the lamp 20 and bends its optical path at a right angle, and the edge portion 11 of the semiconductor wafer 10 is aligned or parallel to the direction connecting the CCD camera 21 and the edge portion 11. In addition, the illumination light is incident on the planar portion 12 in the vicinity thereof, while the reflected light from the planar portion 12 is transmitted and guided to the CCD camera 21.

  The CCD camera 21 is disposed at a position above the surface of the semiconductor wafer 10 and is connected to an image processing device 24 that processes the captured image. The captured image of the edge portion 11 subjected to image processing by the image processing device 24 is enlarged and displayed by the display device 25.

  The reflection mirror 22 is disposed near the edge portion 11 on the back surface side of the semiconductor wafer 10 and at a position facing the lamp 20 and the CCD camera 21. The reflection mirror 22 is equipped with an adjustment mechanism 26 that adjusts the inclination angle of the reflection mirror 22 with respect to the edge portion 11 and the CCD camera 21.

  FIG. 3 is an explanatory view for explaining the operation of the above-described peripheral edge inspection apparatus.

  By the illumination light of the lamp 20, the edge portion of the semiconductor wafer 10 and the planar portion 12 adjacent to the edge portion 11 are coaxially illuminated.

  Illumination light irradiated on the edge portion 11 of the semiconductor wafer 10 is scattered by the edge portion 11, and most of the illumination light does not enter the CCD camera 22 through the half mirror 23, but is adjacent to the edge portion 11. The illumination light that irradiates the planar portion 12 to be reflected is reflected by the planar portion 12, passes through the half mirror 23, and enters the CCD camera 22.

  Illumination light that has passed through the vicinity of the edge portion 11 without hitting the edge portion 11 or the plane portion 12 is reflected by the reflection mirror 22 and enters the CCD camera 21.

  As a result, the light hitting the edge portion 11 and the surface portion 12 and the light hitting the reflection mirror 22 without hitting them can be separated almost completely, and the edge portion 11 can be extracted.

  FIG. 4 shows an example of a photographed image of the edge portion 11 photographed by coaxially illuminating the semiconductor wafer 10 with the peripheral edge inspection apparatus of FIG. FIG. 5 is a photographed image taken by removing the reflecting mirror 22 from the peripheral edge inspection apparatus of FIG. 1 for comparison.

  As shown in FIG. 4, since most of the light irradiated on the edge portion 11 is scattered and does not enter the CCD camera 21, the photographed image appears to be blacked out, but in the vicinity of the edge portion 11. Since the light irradiated there is reflected by the reflecting mirror 22 and enters the CCD camera 21, the photographed image is not assimilated with the edge portion 11 and painted black, and as a result, the edge portion 11 emerges. (Extract). For this reason, it becomes possible to observe the shape, dimension, etc. even if the edge portion 11 is slightly chipped (see the left portion of the notch in FIG. 4).

  When the reflection mirror 22 is removed, as shown in FIG. 5, the light irradiated on the vicinity of the edge portion 11 does not enter the CCD camera 21, so that the captured image is the edge portion 11. Assimilation is painted black, and as a result, the edge portion 11 is buried in the black painted image.

  FIG. 2 shows a modified example of the peripheral edge inspection apparatus shown in FIG.

  A ring light 27 is used instead of the lamp 20 and the half mirror 23. The ring light 27 uniformly illuminates the semiconductor wafer 10 with ring-shaped (360 °) illumination light. A fluorescent lamp is formed in a ring shape, or a plurality of white light emitting diodes are arranged on a ring-shaped body. Configured. The illumination light from the ring light 27 is inclined at a predetermined angle with respect to the illumination light flux of the ring light 27, and illuminates the edge portion 11 and the flat portion 12 from an oblique direction (oblique illumination) rather than from directly above. The ring light 27 is disposed between the semiconductor wafer 10 and the CCD camera 21 at a position above the surface of the semiconductor wafer 10 so that the center of the illumination light beam coincides with the optical axis of the CCD camera 21.

  The optical axis of the CCD camera 21 passes through the central through hole 27a of the ring light 27, and the light reflected from the edge portion 11 and the planar portion 12 of the semiconductor wafer 10 enters the CCD camera 21 through the through hole 27a. In addition, a part of the light that has passed through the edge portion 11 without being irradiated is reflected by the reflection mirror 22 and enters the CCD camera 21 through the through hole 27a.

  The adjustment mechanism 26 adjusts the tilt angle of the reflection mirror 22 with respect to the edge portion 11 and the CCD camera 21 so that the passing light is not missed without irradiating the edge portion 11, so that more light is incident on the CCD camera 21. It can be made.

  FIG. 6 shows an example of a photographed image of the edge portion 11 photographed by obliquely illuminating the semiconductor wafer 10 by the peripheral edge inspection apparatus of FIG. FIG. 7 is a photographed image taken by removing the reflecting mirror 22 from the peripheral edge inspection apparatus of FIG. 2 for comparison.

  As shown in FIG. 6, the light irradiated onto the edge portion 11 by the oblique illumination is scattered, but a part of the light is incident on the CCD camera 21, so that the photographed image is one of the edge portions 11. Only the part appears shining, and the remaining part is painted black. In the vicinity of the edge portion 11, a part of the light irradiated thereon is reflected by the reflection mirror 22 and enters the CCD camera 21, so that the photographed image is not assimilated with the edge portion 11 and painted black. The boundary portion with the edge portion 11 is illuminated, and as a result, the edge portion 11 is raised (extracted). For this reason, it is possible to observe the shape, dimensions, and the like of even a slight chip of the edge portion 11 (see the portion on the left side of the notch in FIG. 6).

  When the reflecting mirror 22 is removed, as shown in FIG. 7, the light irradiated on the edge portion 11 does not enter the CCD camera 21 as shown in FIG. The boundary portion is also assimilated and painted black, and as a result, the edge portion 11 is buried in the black painted image.

  As described above, according to the peripheral edge inspection apparatus shown in FIGS. 1 and 2, it is possible to obtain a detailed photographed image of the edge portion 11 simply by disposing the reflection mirror 22. Therefore, it is not necessary to use a large illuminating device for illuminating from the beginning and to equip a plurality of CCD cameras 21.

  FIG. 8 is a schematic perspective view showing another embodiment of the peripheral edge inspection apparatus of the present invention.

  In the present embodiment, the peripheral edge inspection apparatus shown in FIG. 1 is further equipped with a defect position detection member 40 that detects the position of a defect such as a chip generated in the edge portion 11 of the semiconductor wafer 10. The defect position detection member 40 is opposed to the linear CCD 41 disposed above the front surface of the semiconductor wafer 10 at a position upstream of the CCD camera 21 in the rotation direction of the semiconductor wafer 10 and the linear CCD 28 on the back surface side of the semiconductor wafer 10. And an illumination member 42 arranged as described above. The linear CCD 41 and the lamp 42 are arranged so that the edge portion 10 of the semiconductor wafer 10 is located between them, and a part of the light from the illumination member 42 is blocked by the edge portion 11 and enters the linear CCD 41. It is like that. Since the amount of light of the illumination member 42 blocked by the edge portion 11 is constant, the charge is proportional to the amount of incident light except for the notch previously formed in the edge portion 11 and the chipped portion generated in the edge portion 11. The accumulated output of the linear CCD 41 is proportional to the amount of incident light.

  When the edge portion 11 is illuminated by the illumination member 42 while the semiconductor wafer 10 is rotated by the rotary table 30, the output of the linear CCD 41 is constant because the amount of light of the illumination member 42 blocked by the edge portion 11 is constant. However, since the light quantity of the illumination member 42 to be blocked is changed at the notch formed in the edge portion 11 or the chipped portion generated in the edge portion 11, these portions change between the linear CCD 41 and the illumination member 42. When moving to, the output of the linear CCD 41 changes.

  FIG. 9 is a graph showing changes in the output of the linear CCD 41. The vertical axis represents the output value of the linear CCD 41, and the horizontal axis represents the rotation angle. As shown in the figure, the output of the linear CCD 41 changes at a notch or chipped portion, and the rotation position of the chip (rotation angle from the notch) can be detected from this output change.

  Therefore, if the rotational position information of the chip generated in the edge portion 11 is acquired in advance, when the edge portion 11 in which the chip is generated due to the rotation of the semiconductor wafer 10 moves to the position of the CCD camera 21, the semiconductor once. The wafer 10 can be photographed with the rotation stopped, and the edge portion 11 can be observed and inspected in detail, and the inspection throughput can be improved.

  In the above-described embodiment, the case where the edge portion 11 is coaxially illuminated using the lamp 20 and the half mirror 23 and the case where the ring light 27 is used to obliquely illuminate are shown, but the illumination method is limited to this. It is not something.

  Moreover, although the case where the CCD camera 21 is used is shown, a solid-state amplification type imaging device such as a CMOS can be used.

  Furthermore, although the case where the reflection mirror 22 is used was shown, it is not limited to this, You may use a diffuser plate, white paper, etc. In short, the light passing through the edge portion 11 may be returned to the observation member such as the CCD camera 21.

It is a schematic side view which shows one Embodiment of the periphery test | inspection apparatus of this invention. It is a schematic side view which shows the modification of the periphery test | inspection apparatus of FIG. It is explanatory drawing explaining an effect | action of the periphery test | inspection apparatus of FIG. 2 is a photographed image of an edge portion 11 photographed by coaxially illuminating a semiconductor wafer 10 with the peripheral edge inspection apparatus of FIG. 1. FIG. 4 is a photographed image of the edge portion 11 taken by removing the reflection mirror 22 from the peripheral edge inspection apparatus of FIG. 1 for comparison. FIG. 3 is a photographed image of an edge portion 11 photographed by obliquely illuminating the semiconductor wafer 10 by the peripheral edge inspection apparatus of FIG. 2. For comparison, it is a photographed image of the edge portion 11 photographed by removing the reflecting mirror 22 from the peripheral edge inspection apparatus of FIG. It is a schematic perspective view which shows other embodiment of the periphery test | inspection apparatus of this invention. It is a graph which shows the output change of the linear CCD of the periphery test | inspection apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor wafer 11 Edge part 12 Plane part 20 Lamp (illumination member)
21 CCD camera (observation member)
22 Reflective mirror (reflective member)
24 Image processing device 26 Adjustment device 27 Ring light (illumination member)
30 Rotary table (support member)
40 Defect position detection member 41 Linear CCD
42 Illumination member

Claims (8)

A support member for supporting the object to be inspected;
An illumination member that illuminates the periphery of the object to be inspected;
An observation member for observing the periphery of the inspection object;
And a reflecting member that reflects light that has passed through the vicinity of the periphery toward the observation member. The peripheral edge inspection apparatus according to claim 1,
The peripheral inspection apparatus, wherein the reflecting member is disposed at a position facing the illumination member with the inspection object interposed therebetween. In the peripheral inspection apparatus according to claim 1 or 2,
The peripheral inspection apparatus, wherein the reflection member is configured to be adjustable in angle with respect to the peripheral edge and / or the observation member. In the peripheral inspection apparatus according to any one of claims 1 to 3,
The peripheral inspection apparatus, wherein the illumination member illuminates the periphery with illumination light parallel or inclined to a direction connecting the observation member and the periphery observed by the observation member. In the peripheral inspection apparatus according to any one of claims 1 to 4,
The observation member includes an image sensor,
An edge inspection apparatus, comprising: an image processing apparatus that detects an image output of the periphery captured by the image sensor and detects a shape and size of the defect on the periphery. In the peripheral inspection apparatus according to any one of claims 1 to 5,
A defect position detection member for detecting a defect position at the periphery of the inspection object;
The support member has a rotation mechanism for rotating the inspection object,
A peripheral inspection apparatus, wherein a defect position on a peripheral edge of the inspection object is detected by the defect position detection apparatus while rotating the inspection object by the rotation mechanism. Rotating the object to be inspected;
Irradiating illumination light to the periphery of the inspection object;
Photographing the peripheral edge irradiated with the illumination light;
And a step of reflecting the illumination light toward the image sensor during the photographing step. In the peripheral inspection method according to claim 7,
A peripheral inspection method, further comprising a step of detecting a defect position on the peripheral edge.