JP2007294604A - Device and method for inspecting external appearance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method for inspecting an external appearance that can detect defects present on the top surface and reverse surface of a sample at the same time. <P>SOLUTION: The device 1 for inspecting the external appearance which detects defects appearing on external surfaces of the sample 2 includes defect detecting units (20a and 20b) which detect a first defect group appearing in a reflected optical image reflected by one of the top and reverse surfaces of the sample 2 and a second defect group appearing in a transmitted optical image transmitted through the sample 2, and a defect comparing unit (25) which compares the first and second defect groups with each other to detect the defect appearing on the other of the top and reverse surfaces. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method for detecting defects appearing on the outer surface of a sample, and in particular, formed on the outer surface of a semiconductor wafer, a photomask substrate, a liquid crystal panel substrate, a liquid crystal device substrate, or the like. The present invention relates to an appearance inspection apparatus and an appearance inspection method for detecting a pattern defect. More specifically, the present invention relates to a technique for simultaneously detecting defects existing on the front surface and the back surface of these samples.

The manufacture of semiconductor devices such as semiconductor wafers, photomasks, and liquid crystal display panels consists of many man-hours. Inspecting the occurrence of defects in the final and intermediate processes and feeding them back to the manufacturing process improves yield. Is also important. In order to detect such defects in the middle of the manufacturing process, defects that appear in the appearance of patterns formed on the outer surface of samples such as semiconductor wafers, photomask substrates, liquid crystal display panel substrates, and liquid crystal device substrates are detected. Visual inspection such as pattern defect inspection is widely performed.
In the following description, a semiconductor wafer appearance inspection apparatus for inspecting defects in a pattern formed on a semiconductor wafer will be described as an example. However, the present invention is not limited to this, and can be widely applied to appearance inspection apparatuses for inspecting semiconductor devices such as a semiconductor memory photomask substrate, a liquid crystal display panel substrate, and a liquid crystal device substrate. .

  FIG. 1 shows a block diagram of an appearance inspection apparatus similar to that proposed by the applicant of the present application in Japanese Patent Application No. 2003-188209 (the following Patent Document 1). In general, the appearance inspection apparatus 1 includes a microscope unit 10 for obtaining a captured image of a semiconductor wafer 2 (hereinafter simply referred to as “wafer”), and an image for analyzing the acquired image and detecting defects appearing on the surface of the wafer 2. And a processing unit 20.

FIG. 1 shows a block diagram of an appearance inspection apparatus proposed by the applicant of the present patent application in Japanese Patent Application No. 2003-188209 (the following Patent Document 1). As shown in the drawing, a sample stage (chuck stage) 12 is provided on the upper surface of a stage 11 that can move freely in a two-dimensional direction. The stage 11 can move in the two-dimensional direction of the X direction and the Y direction, and can move the wafer 2 in the three-dimensional direction by raising and lowering the sample stage 12 in the Z direction. On this sample stage, the semiconductor wafer 2 to be inspected is placed and fixed. An imaging unit 13 configured using a one-dimensional or two-dimensional CCD camera or the like is provided on the upper part of the stage, and the imaging unit 13 generates an image signal of a pattern formed on the semiconductor wafer 2.
In the present embodiment, a one-dimensional TDI camera is used for the imaging unit 13 and the stage 11 is moved to cause the imaging unit 13 to scan relative to the wafer 2 at a constant speed in the X direction or the Y direction. A two-dimensional image is obtained.

  Further, for the sake of simplicity, an appearance inspection apparatus including a bright field illumination optical system will be described as an example, but the present invention is not limited to this. The appearance inspection apparatus also employs a dark field illumination optical system that does not directly capture illumination light, and an appearance inspection apparatus having a dark field illumination optical system is also an object of the present invention. In some cases, the dark field device does not use an image sensor, but this is also an object of the invention.

  As shown in FIG. 2, a plurality of dies (chips) 3 are repeatedly arranged in a matrix on the wafer 2 in the X direction and the Y direction, respectively. Since the same pattern is formed on each die, the images obtained by imaging these dies should be essentially the same, and the pixel values of the corresponding portions of the captured images of each die are essentially the same values.

Therefore, if a difference in pixel values (gray level difference signal) between corresponding parts of the captured images of the two dies is detected, gray is detected when one die is defective compared to when both dies are not defective. By increasing the level difference signal, defects present on the die can be detected (die-to-die comparison).
Further, when a repeated pattern such as a memory cell is formed in one die, a defect is detected even if a gray level difference between images obtained by imaging a plurality of locations that should be the same in the repeated pattern is detected. Can be detected (cell-to-cell comparison).
In die-to-die comparison, it is common to compare images obtained by imaging two adjacent dies (single detection). Since this does not know which die is defective, it is further compared with the adjacent die on the different side, and if the gray level difference of the same part becomes larger than the threshold again, it is found that the die is defective ( Double detection). The same applies to the cell-to-cell comparison.

Returning to FIG. 1, the appearance inspection apparatus 1 compares the portions that should originally be the same in the captured image obtained by imaging the repetitive pattern formed on the surface of the semiconductor wafer 2 with the imaging unit 13, and compares the surface of the semiconductor wafer 2. The defect detection part 20 which detects the defect which appears in is provided.
The image signal output from the imaging unit 13 is converted into a multi-value digital signal (gray level signal) and then stored in the image storage unit 21 in the defect detection unit 20.
When the imaging unit 13 is scanned relative to the wafer 2 by moving the stage 11 and an output signal of the imaging unit 13 that is a one-dimensional TDI camera is captured during this time, an image of the wafer 2 is accumulated in the image storage unit 21. The

The defect detection unit 20 includes a difference detection unit 22 for calculating a gray level difference between corresponding portions of the captured images of the two dies in the image of the wafer 2 stored in the image storage unit 21.
When performing die-to-die comparison, the difference detection unit 22 takes out a partial image of a corresponding portion of a plurality of adjacent dies from the image storage unit 21, and sets one of them as an inspection image and the rest as a reference image. Then, a gray level difference signal between corresponding pixels between the inspection image and the reference image is calculated and output to the detection threshold value calculation unit 23 and the detection unit 24.
In the case of performing cell-to-cell comparison, the difference detection unit 22 similarly takes out a partial image of a corresponding portion of a plurality of adjacent cells from the image storage unit 21, and uses one as an inspection image and the rest as a reference image. Calculate the gray level difference.

The detection threshold calculation unit 23 determines a defect detection threshold from the gray level difference and outputs the defect detection threshold to the detection unit 24. The detection unit 24 detects the defect included in the inspection image by comparing the gray level difference input from the difference detection unit 22 with the defect detection threshold determined by the detection threshold calculation unit 23.
That is, when the gray level difference signal exceeds the defect detection threshold, the detection unit 24 determines that the inspection image includes a defect at the pixel position where the gray level difference signal is calculated.
The detection unit 24 creates and outputs defect information including information such as the position and size of the detected defect, the gray level difference signal at the time of detection, and the gray level value for each detected defect.

JP 2004-177397 A Japanese Patent Laid-Open No. 2003-203883

The appearance inspection apparatus as described above detects only defects existing on the surface on which the pattern is formed among the front and back surfaces of the wafer, and does not consider the defects existing on the back surface. This is because even if there is a defect on the back surface, the operation of the finally manufactured semiconductor device is not affected.
However, if particles adhere to the back surface of the wafer during the semiconductor manufacturing process, the back surface of the wafer becomes a source of new particles. That is, when the particles on the back surface of the wafer move to the wafer surface, pattern formation on the wafer surface may be hindered in a later process.

For example, in a wet cleaning process in which the wafer surface is cleaned with hydrogen fluoride (HF), a batch method is employed in which a plurality of wafers are stacked and cleaned together. In such a process, a state in which the back surface of a certain wafer is close to the surface of the adjacent wafer is created, so that there is a high possibility that particles on the back surface of the wafer will move to another wafer surface.
Further, in the photolithography process, there is a problem in that the resolution performance of the pattern transferred to the wafer is lowered due to the presence of particles between the sample stage holding the wafer and the back surface of the wafer.

However, in the conventional appearance inspection apparatus, it is possible to image only one of the front surface and the back surface of the wafer, the surface facing the imaging device side or the surface contacting the sample table, and a pattern is formed in either case. Only defects present on the wafer surface could be detected. Therefore, in order to detect defects on both sides of the wafer, it is necessary to inspect one side and then turn the wafer over to inspect the other side, resulting in a decrease in throughput of appearance inspection.
In view of the above problems, an object of the present invention is to provide an appearance inspection apparatus and an appearance inspection method capable of simultaneously detecting defects present on the front surface and the back surface of a sample.

  In order to achieve the above object, in the present invention, defects appearing in the respective images are detected in the reflected optical image reflected by one of the front and back surfaces of the sample and the transmitted optical image transmitted through the sample. The difference between the detected defects is detected as a defect that appears on the other of the front and back surfaces.

  That is, according to the first aspect of the present invention, in the appearance inspection apparatus for detecting defects appearing on the outer surface of the sample, the first defect group appearing in the reflected optical image reflected by one of the front surface and the back surface of the sample. And a defect detection unit that detects a second defect group appearing in a transmission optical image transmitted through the sample, and the first defect group and the second defect group are compared to compare the other of the front surface and the back surface of the sample. There is provided an appearance inspection apparatus that includes a defect comparison unit that detects a defect appearing on a surface.

  Further, according to the second aspect of the present invention, there is provided an appearance inspection method for detecting a defect appearing on the outer surface of a sample, which generates a reflected optical image reflected on one of the front surface and the back surface of the sample, A transmission optical image transmitted through the reflection optical image, a first defect group appearing in the reflection optical image is detected, a second defect group appearing in the transmission optical image is detected, and the first defect group, the second defect group, And a visual inspection method for detecting a defect appearing on the other one of the front surface and the back surface.

  In each of the embodiments of the present invention described above, infrared light is included in order to generate a transmission optical image by transmitting the sample to the sample using the fact that the silicon wafer that is the material of the semiconductor wafer transmits infrared light. Light may be used as illumination light.

According to the present invention, defects existing on both sides of the sample can be detected simultaneously, so that defects such as particles existing on the back surface of the sample or inside the sample are detected without reducing the throughput of the appearance inspection. It becomes possible.
Also, assuming that a defect present on one surface of the sample is detected from the reflected optical image and a defect present on the other surface is detected from the transmitted optical image, the transmitted optical image is present on the other surface. In addition to the defects that appear, defects that exist on one side also appear. Therefore, in order to detect only the defects existing on the other surface, it is necessary to remove the defects existing on one surface appearing in the transmitted optical image. This process directly compares the reflected optical image and the transmitted optical image by detecting the difference after detecting the defect in each of the reflected optical image and the transmitted optical image as a defect existing on the second surface. This can be realized with a smaller processing amount.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 3 is a block diagram of a first configuration example of the appearance inspection apparatus according to the embodiment of the present invention. Among the components of the appearance inspection apparatus 1 shown in FIG. 3, the same reference numerals are given to the same components as those included in the appearance inspection apparatus shown in FIG.

The appearance inspection apparatus 1 shown in FIG. 3 includes a microscope unit 40 for obtaining a captured image of the outer surface of the wafer 2 as a sample, and an image processing unit 50 that analyzes the acquired image and detects defects appearing on the outer surface of the wafer 2. And is configured.
The microscope unit 40 includes an objective lens 43 that projects an optical image of the outer surface of the wafer 2, and two imaging units 13 a and 13 b that capture an optical image of the outer surface of the wafer 2 projected by the objective lens 43. A one-dimensional or two-dimensional CCD camera can be used for the imaging units 13a and 13b, and an image sensor such as a TDI camera is preferably used. The imaging units 13a and 13b convert the optical image of the outer surface of the wafer 2 formed on the light receiving surface into an electric signal. In the present embodiment, a one-dimensional TDI camera is used for the imaging units 13a and 13b, and the stage 11 is moved so that the imaging units 13a and 13b are relatively scanned on the wafer 2 at a constant speed in the X direction or the Y direction. .

Here, regarding the notation of the front surface and the back surface of the wafer 2, the surface on which the pattern is formed is referred to as “front surface”, and the opposite surface is referred to as “back surface”. In addition, the surface facing the imaging unit side of the microscope unit 40 among the front and back surfaces of the wafer 2 is referred to as a “first surface”, and the opposite surface is referred to as a “second surface”. To do.
The surface of the wafer 2 does not have to be the “first surface” facing the imaging unit side of the microscope unit 40, and the appearance inspection may be performed with the back surface of the wafer 2 facing the imaging unit side of the microscope unit 40. Good.

  Further, the microscope section 40 includes a normal light source 41a for illuminating the wafer 2 with normal visible light, a condensing lens 42a thereof, and a semi-transparent mirror (beam splitter) 44a provided on the projection optical path of the objective lens 43. . The semi-transparent mirror 44a reflects the illumination light of the visible light collected by the condenser lens 42a toward the objective lens 43, and the projection light of the reflected optical image of the first surface of the wafer 2 projected by the objective lens 43. Transparent.

The microscope unit 40 further includes an infrared light source 41b for illuminating the wafer 2 with illumination light having a wavelength in the infrared region (hereinafter simply referred to as “infrared light”), its condensing lens 42b, and an objective lens. A semi-transparent mirror (beam splitter) 44b provided on the projection optical path 43 is provided. The semi-transparent mirror 44 b reflects the infrared illumination light collected by the condenser lens 42 b toward the objective lens 43.
The infrared illumination light that has passed through the objective lens 43 is irradiated onto the wafer 2, passes through the wafer 2, reflects off the surface of the sample stage 12, and then passes through the wafer 2 again. The objective lens 43 projects the transmitted optical image, and the projected light passes through the semi-transparent mirrors 44a and 44b. The surface of the sample stage 12 is preferably mirror-finished in order to efficiently reflect infrared light transmitted through the wafer 2.

The projection light obtained by combining the reflected optical image by the visible light reflected by the first surface of the wafer 2 and the transmitted optical image by the infrared light transmitted through the wafer 2 is a half mirror 45 provided on the projection optical path of the objective lens 43. The projection light that has been split by and reflected by the half mirror 45 is imaged on the light receiving surface of the normal light imaging unit 13a by the imaging optical system 46a.
The normal light imaging unit 13a is composed of a white light camera, and generates an analog image signal by converting only a reflected optical image of visible light into an electrical signal out of the formed reflected optical image and transmitted optical image. Further, it is converted into a multi-value digital signal (gray level signal) and output to the image processing unit 50.

  On the other hand, each optical image transmitted through the half mirror 45 is imaged on the light receiving surface of the infrared light imaging unit 13b, which is an infrared light camera, by the imaging optical system 46b. At this time, only the transmitted optical image is formed on the infrared light imaging unit 13b by passing through the wavelength selection filter 47 that transmits only the infrared light. The infrared light imaging unit 13b converts the formed transmission optical image into an electric signal to generate an analog image signal, and further converts it into a multi-value digital signal (gray level signal) and outputs it to the image processing unit 50. To do.

The image signal of the reflection optical image and the image signal of the transmission optical image input to the image processing unit 50 are input to the normal light image defect detection unit 20a and the infrared light image defect detection unit 20b, respectively.
The normal light image defect detection unit 20a and the infrared light image defect detection unit 20b may be realized by the same configuration as the defect detection unit 20 illustrated in FIG. Then, the normal light image defect detection unit 20a detects the first defect group appearing in the reflected optical image by comparing portions that should be originally identical in the captured image of the reflected optical image, and detects the first defect group. The defect information described above is output for each defect included in the defect group.
Here, since the aspect of the first surface facing the imaging units 13a and 13b of the front surface and the back surface of the wafer 2 appears in the reflected optical image, the first optical image defect detection unit 20a detects the first surface. The defect group includes only defects that appear on the first surface of the wafer 2.

  On the other hand, the infrared light image defect detection unit 20b detects a second defect group appearing in the transmission optical image by comparing portions that should originally be the same in the captured image of the transmission optical image, and detects the second defect group. The defect information is output for each defect included in the defect group. Here, in the transmitted optical image, aspects of both the front surface and the back surface of the wafer 2 appear. Therefore, the second defect group detected by the infrared light image defect detection unit 20b includes defects appearing on the first surface of the wafer 2 in addition to defects appearing on the second surface of the wafer 2.

The defect comparison unit 25 inputs defect information related to the first defect group and defect information related to the second defect group, respectively, from the normal light image defect detection unit 20a and the infrared light image defect detection unit 20b. Then, by comparing these defect information, the defects included in the first defect group are removed from the defects included in the second defect group, and the remaining defect groups (that is, the first defect group and the second defect group) are removed. Difference from the group) is extracted as defect information of defects existing on the second surface of the wafer 2.
At this time, the defect comparison unit 25 determines whether the defect included in the second defect group is also included in the first defect group, and the defect included in the first defect group and the second defect. By comparing the positional information of the defects included in the defect information of these defects with the defects included in the group, the defects included in the first defect group and the defects included in the second defect group To determine the identity between.

  Then, the image processing unit 50 outputs the defect information output from the normal light image defect detection unit 20a as the defect information of the defects existing on the first surface of the wafer 2, and the defect information output from the defect comparison unit 25. Output as defect information of defects present on the second surface of the wafer 2.

FIG. 4 is a flowchart illustrating an example of an appearance inspection method according to an embodiment of the present invention.
In step S1, an illumination optical system including a normal light source 41a that provides visible illumination light (for example, the normal light source 41a, the condensing lens 42a, the semi-transparent mirror 44a, and the objective lens 43 in the configuration example of FIG. 3) is used for the wafer. Illuminate 2.
In step S2, an illumination optical system including an infrared light source 41b that provides infrared illumination light (for example, in the configuration example of FIG. 3, the infrared light source 41b, the condensing lens 42b, the semi-transparent mirror 44b, and the objective lens 43). The wafer 2 is illuminated by

In step S <b> 3, the reflected optical image generated by reflecting the visible illumination light on the first surface of the wafer 2 and the infrared illumination light is transmitted through the wafer 2 and reflected on the surface of the sample table 12. After that, a transmission optical image generated by passing through the wafer 2 again is projected by the objective lens 43. The projected optical image is captured by the normal light imaging unit 13a. For example, in the configuration example of FIG. 3, the projection light is reflected by the half mirror 45 and imaged on the light receiving unit of the normal light imaging unit 13a by the imaging optical system 46a.
By imaging the formed reflected optical image and transmitted optical image with the normal light imaging unit 13a that is a white light camera, only the reflected optical image by visible light is converted into an electrical signal to generate an analog image signal. Further, it is converted into a multi-value digital signal (gray level signal) and output to the image processing unit 50.

  In step S4, the projected optical image is captured by the infrared light imaging unit 13b. For example, in the configuration example of FIG. 3, the projection light transmitted through the half mirror 45 out of the projection light of the reflected optical image and the transmitted optical image projected by the objective lens 43 is transmitted by the infrared light camera by the imaging optical system 46a. An image is formed on the light receiving surface of a certain infrared imaging unit 13b. At this time, the infrared light imaging unit 13b captures only the transmitted optical image of the infrared light through the wavelength selection filter 47 that transmits only the infrared light. The obtained analog image signal is converted into a multi-value digital signal (gray level signal) and output to the image processing unit 50.

  In step S5, the normal light image defect detection unit 20a of the image processing unit 50 compares the portions that should originally be the same in the captured image of the reflection optical image captured by the normal light image capturing unit 13a, thereby reflecting the reflected optical image. The first defect group appearing on the first defect group is detected, and the defect information described above is output for each defect included in the first defect group. As described above, since the first defect group includes only defects appearing on the first surface of the wafer 2, the image processing unit 50 obtains defect information about each defect included in the first defect group as the first defect group. Output as defect information of defects appearing on the surface.

  In step S6, the infrared light image defect detection unit 20b compares the portions that should be the same in the captured optical image captured by the infrared light imaging unit 13b with each other and appears in the transmitted optical image. Two defect groups are detected, and defect information is output for each defect included in the second defect group. Here, as described above, the second defect group includes defects appearing on the first surface in addition to defects appearing on the second surface of the wafer 2.

  In step S7, the defect comparison unit 25 inputs defect information about the first defect group and defect information about the second defect group, respectively, from the normal light image defect detection unit 20a and the infrared light image defect detection unit 20b. . Then, the difference between these defect information is extracted as defect information of defects existing on the second surface of the wafer 2. The extraction method may be the same as in the above example. The difference between the defect information is output as defect information of the defect appearing on the second surface.

As described above, according to the present invention, defects existing on the front surface and the back surface of the wafer 2 can be detected simultaneously, and the appearance inspection of the back surface of the wafer 2 can be performed without impairing the throughput of the appearance inspection apparatus 1. It becomes possible. Note that since the internal state of the wafer 2 also appears in the transmission optical image, the second defect group includes defects inside the wafer 2. Therefore, it is possible to extract defects inside the wafer 2 by the defect comparison unit 25.
Also, as a method of extracting only the defects appearing on the second surface from the transmission optical image, a method of generating a difference image between the transmission optical image and the reflection optical image can be considered, but in this method, only detected defect information is compared. Therefore, the processing amount is reduced as compared with the method using such a difference image. Further, in such a method using the difference image, it is necessary to perform image adjustment between the transmission optical image and the reflection optical image in order to accurately remove only the defect appearing on the first surface from the transmission optical image. Since this method does not require such a delicate adjustment process, it is possible to accurately extract only the defects appearing on the second surface.

FIG. 5 is a block diagram showing a second configuration example of the appearance inspection apparatus according to the embodiment of the present invention. In this configuration example, the normal light imaging unit 13a and the infrared light imaging unit 13b illustrated in FIG. For example, such an imaging unit 13 is provided with a wavelength selection filter that transmits infrared light every other light receiving cell arranged in the imaging device, and such an infrared transmission wavelength selection filter is provided. An electric signal obtained only by the light receiving cell and an electric signal obtained only by the light receiving cell without the infrared transmission wavelength selection filter are output as separate image signals.
Then, the image signal obtained only by the light receiving cell without the infrared transmission wavelength selection filter is input to the normal light image defect detection unit 20a of the image processing unit 50 as a reflected optical image by visible light, and the infrared transmission wavelength selection filter An image signal obtained by only the light receiving cell is input to the infrared light image defect detection unit 20b of the image processing unit 50 as a transmission optical image by infrared light. The configuration and operation of the image processing unit 50 are the same as those in the configuration example of FIG.

FIG. 6 is a block diagram showing a third configuration example of the appearance inspection apparatus according to the embodiment of the present invention. In the configuration example shown in FIG. 3, infrared illumination light is irradiated from the first surface of the wafer 2, that is, the surface facing the infrared light imaging unit 13, but in this embodiment, the first surface is irradiated. The second surface on the back side is irradiated.
Therefore, in this configuration example, as illustrated, the infrared light sources 41b and 42b are arranged on the second surface side of the wafer 2, or the illumination light from the infrared light source 41b is used as the second light source of the wafer 2. Light guide means such as an optical fiber is provided to change the direction of illumination light to the second surface side.

Further, an edge clamp 60 that holds the wafer 2 by contacting the side surface of the wafer 2 is provided in place of the sample table 12 shown in FIG. 3 so as not to block the illumination light that is illuminated from the second surface side. The edge clamp 60 may grip a peripheral region where the pattern is not formed on the front surface and the back surface of the wafer 2. Or you may make it transmit the illumination light which comprises the upper surface member of the sample stand 12 supporting the 2nd surface of the wafer 2 by a transparent member, and illuminates from the 2nd surface side.
Compared to the configuration example of FIG. 3 in which a transmission optical image transmitted twice through the wafer 2 is irradiated by irradiating infrared light from the first surface, in this configuration example, the number of transmissions in the wafer 2 is one. Therefore, there is an advantage that the scale of the infrared light source 41b can be reduced. Other components in this configuration example are the same as those in the configuration example of FIG.
Further, in the configuration example in which the illumination light of the infrared light shown in FIG. 6 is illuminated from the second surface of the wafer 2, the normal light imaging unit 13 a and the infrared light imaging unit 13 b are similar to the configuration example in FIG. 5. Can be realized by a single imaging unit.
Further, in the configuration examples of FIGS. 3, 5 and 6, by using a light source (for example, a halogen lamp) including both infrared light and normal light wavelength bands as the light source, the two light sources 41a and 41b are converted into one light source. You may comprise by a unit.

  The present invention can be used for an appearance inspection apparatus and an appearance inspection method for detecting defects appearing on the outer surface of a sample. In particular, the present invention can be used in an appearance inspection apparatus and an appearance inspection method for detecting defects in patterns formed on the outer surfaces of semiconductor wafers, photomask substrates, liquid crystal panel substrates, liquid crystal device substrates, and the like.

It is a block diagram of the conventional appearance inspection apparatus. It is a figure which shows the arrangement | sequence of the die | dye on a semiconductor wafer. It is a block diagram which shows the 1st structural example of the external appearance inspection apparatus by the Example of this invention. It is a flowchart which shows the example of the external appearance inspection method by the Example of this invention. It is a block diagram which shows the 2nd structural example of the external appearance inspection apparatus by the Example of this invention. It is a block diagram which shows the 3rd structural example of the external appearance inspection apparatus by the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Appearance inspection apparatus 2 Semiconductor wafer 40 Microscope part 43 Objective lens 47 Wavelength selection filter 50 Image processing part

Claims (4)

In the visual inspection device that detects defects appearing on the outer surface of the sample,
A defect detection unit for detecting a first defect group appearing in a reflected optical image reflected by one of the front and back surfaces of the sample and a second defect group appearing in a transmitted optical image transmitted through the sample When,
Comparing the first defect group and the second defect group, and detecting a defect appearing on the other of the front and back surfaces of the sample;
An appearance inspection apparatus comprising: A light source unit for supplying illumination light including infrared light;
The appearance inspection apparatus according to claim 1, wherein the illumination light supplied from the light source unit is transmitted through the sample to generate the transmission optical image. In the visual inspection method for detecting defects appearing on the outer surface of the sample,
Generating a reflected optical image reflected on one of the front and back surfaces of the sample;
Generating a transmission optical image transmitted through the sample;
Detecting a first defect group appearing in the reflected optical image;
Detecting a second defect group appearing in the transmission optical image;
Comparing the first defect group and the second defect group to detect a defect appearing on the other of the front and back surfaces of the sample;
An appearance inspection method characterized by that.   4. The appearance inspection method according to claim 3, wherein a transmission optical image transmitted through the sample is generated by transmitting illumination light including infrared light through the sample to generate the transmission optical image.

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