JPH07296147A - Device and method for recognizing id of semiconductor wafer - Google Patents

Abstract

PURPOSE:To provide the device and method for recognizing ID of semiconductor wafer capable of exactly recongiging an identifier in a short time. CONSTITUTION:A control circuit 11 receives information on the surface of a semiconductor wafer 7 from a host CPU4 for each manufacture process and adjusts the voltage or current of a light source 2 based on the information, so that the intencity of reflected light to be received at a photodetector 1 can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer ID recognition apparatus and method for imaging and recognizing an identifier (ID) provided on the surface of a semiconductor wafer.

[0002]

2. Description of the Related Art In general, characters or symbols are provided on the surface of a semiconductor wafer as an identifier (ID) representing the information of the semiconductor wafer. These characters or symbols are formed of a material having a reflectance different from that of the surface of the semiconductor wafer, or formed by cutting the surface of the semiconductor wafer. As a device that recognizes such an identifier,
For example, there is one shown in FIG.

In FIG. 4, a light source 2 and a light projecting lens system 3 are arranged obliquely above a semiconductor wafer 7, and a diaphragm 19, an imaging lens 6 and a light receiver 1 are sequentially arranged directly above the semiconductor wafer 7. The light receiver 1 is composed of a CCD camera or the like,
A recognition circuit 5 is connected to the light receiver 1, and the recognition circuit 5 includes a diaphragm driving motor 2 for adjusting the aperture of the diaphragm 19.
0 is connected. In addition, the recognition circuit 5 has a higher CPU 4
Are connected. An identifier 8 made of a material having a reflectance different from that of the semiconductor wafer 7 is formed on the surface of the semiconductor wafer 7.

Next, the image pickup operation will be described. First,
The surface of the semiconductor wafer 7 is obliquely illuminated by the light source 2 and the projection lens system 3, and the reflected light is imaged on the light receiver 1 by the imaging lens 6. At this time, since the reflectance of the identifier 8 is different from the reflectance of the surface of the semiconductor wafer 7, the projection lens system 3
Incident light 9 incident on the surface of the semiconductor wafer 7 via
Considering a, 9b and 9c, the reflected light 1 from the identifier 8
0b and the reflected light 10a and 10c from the portion where the identifier 8 does not exist cause an intensity difference. The identifier 8 such as a character or a symbol is imaged by this difference in intensity.

The identifier 8 imaged in this way is image-recognized by the recognition circuit 5 according to the flow chart shown in FIG. First, the recognition circuit 5 is the upper CPU
When the reading command is received from 4, the image is input from the light receiver 1 in step S1 and the received light intensity is determined in step S2. That is, the brightness of, for example, 256 gradations for each pixel of the image captured in step S1 is accumulated, and it is determined whether or not the accumulated value is within a preset brightness range. If the total value is within the set range, it is determined that the image is captured with an appropriate received light intensity, and the recognition circuit 5 proceeds to step S3 to recognize the identifier 8 composed of characters or symbols from the input image. When the identifier 8 is recognized (step S4), the recognition circuit 5 sets the recognition result in step S5 and transmits it to the upper CPU 4.

On the other hand, if the cumulative value is not within the set range in step S2, it is determined that the received light intensity is inappropriate, and the aperture driving motor 20 is driven in step S6 to open the aperture 19. After adjusting the degree by a predetermined amount, the process returns to step S1 to input an image from the light receiver 1. In this way, steps S6, S1 and S2 are performed until the received light intensity is determined to be appropriate in step S2.
Is repeated.

If the recognition of the identifier 8 is not successful in step S4, the process proceeds to step S7 to check the number N of times of recognition of the identifier. If it is less than the set number of times, the aperture adjustment is performed in step S6. After that, the process returns to step S1 to input an image, and then step S2
In step S3, the received light intensity is determined, and in step S3, the identifier is recognized. If it is determined in step S7 that the number N of repetitions of identifier recognition exceeds the set number of times, an error code is set in step S8 and transmitted to the upper CPU 4.

[0008]

However, the reflectance of the surface of the semiconductor wafer 7 greatly differs depending on the manufacturing process and the type of device to be manufactured. Therefore, it is necessary to appropriately set the illumination intensity for each process of the semiconductor wafer 7. In the method shown in the flowchart of FIG. 5 described above, it is determined whether the received light intensity is appropriate based on the input image that has been taken in, and the amount of light entering the light receiver 1 is adjusted by the diaphragm 19 according to the determination result. Besides, as a method of setting the received light intensity, it is also possible to adjust the amount of light irradiated to the semiconductor wafer 7 by changing the voltage and current supplied to the light source 2. However, in any of the methods, it is necessary to repeat trial and error several times before setting an appropriate received light intensity, which complicates the control of received light intensity and requires a long time until the received light intensity is set. This leads to an increase in the entire processing time of the semiconductor wafer 7. Further, there is a possibility that an appropriate received light intensity cannot be found within a predetermined time and the identifier cannot be recognized.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor wafer ID recognition apparatus and method capable of surely recognizing an identifier in a short time. .

[0010]

According to a first aspect of the present invention, there is provided a semiconductor wafer ID recognition apparatus which comprises a host computer system having information on a semiconductor wafer to be processed and information on each manufacturing process, and a surface of the semiconductor wafer. Illuminating means for illuminating, a light receiver for receiving reflected light from the semiconductor wafer, a recognition means for processing an image from the light receiver to recognize an identifier formed on the surface of the semiconductor wafer, and for each manufacturing process. And a control means for receiving the information from the host computer system and controlling the intensity of the reflected light received by the light receiver based on the information.

According to a second aspect of the semiconductor wafer ID recognition apparatus of the first aspect, the control means controls the intensity of the illumination light emitted from the illumination means.

According to a third aspect of the present invention, there is provided a semiconductor wafer ID recognition apparatus according to the first aspect, wherein the control means adjusts the aperture arranged between the semiconductor wafer and the light receiver and the aperture of the aperture. A diaphragm drive means is included.

According to a fourth aspect of the semiconductor wafer ID recognition method, information regarding a semiconductor wafer to be processed is received for each manufacturing process, and reflected light having an intensity preset for the information regarding the semiconductor wafer is received. By illuminating the surface of the semiconductor wafer and receiving the reflected light from the semiconductor wafer, the image of the identifier formed on the surface of the semiconductor wafer is captured, and the captured image is processed to recognize the identifier. is there.

A semiconductor wafer ID recognition method according to a fifth aspect is the method according to the fourth aspect, wherein the intensity of the illumination light for illuminating the semiconductor wafer is adjusted to set the received intensity of the reflected light to the set intensity.

A semiconductor wafer ID recognizing method according to a sixth aspect is the method according to the fourth aspect, wherein the reflected light from the semiconductor wafer is narrowed to set the received light intensity of the reflected light to the set intensity.

[0016]

In the semiconductor wafer ID recognition apparatus according to the first aspect, the control means receives information from the host computer system for each manufacturing process and controls the intensity of the reflected light received by the light receiver based on the information. An appropriate received light intensity can be set without repeating trial and error.

In the semiconductor wafer ID recognition apparatus according to a second aspect of the present invention, in the apparatus of the first aspect, the control means sets the received light intensity by directly controlling the intensity of the illumination light emitted from the illumination means. It is possible to adjust the received light intensity without using it.

According to a third aspect of the semiconductor wafer ID recognition apparatus of the first aspect, in the apparatus of the first aspect, the control means sets the received light intensity by adjusting the aperture of the diaphragm using the diaphragm driving means. It is possible to easily adjust the received light intensity even when an illuminating means whose intensity is difficult to control is used.

In the semiconductor wafer ID recognition method according to the fourth aspect, information regarding the semiconductor wafer to be processed is received for each manufacturing process, and reflected light having a preset intensity for the information regarding the semiconductor wafer is received. Since the surface of the semiconductor wafer is illuminated as described above, the identifier can be surely recognized without repeating trial and error.

In the semiconductor wafer ID recognition method according to a fifth aspect, in the method according to the fourth aspect, the received light intensity of the reflected light is set to the set intensity by adjusting the intensity of the illumination light, so that no diaphragm is used. The received light intensity can be adjusted.

In the semiconductor wafer ID recognition method according to a sixth aspect, in the method according to the fourth aspect, since the reflected light from the semiconductor wafer is narrowed to set the received light intensity of the reflected light to the set intensity, the intensity of the illumination light is changed. Even when it is difficult to control, the received light intensity can be easily adjusted.

[0022]

【Example】

Example 1. 1 is a block diagram showing a semiconductor wafer ID recognition device according to a first embodiment of the present invention. In FIG. 1, the light source 2 and the light projecting lens system 3 are arranged obliquely above the semiconductor wafer 7, and the imaging lens 6 is provided directly above the semiconductor wafer 7.
The light receiver 1 is arranged via the. The light receiver 1 is a CCD
A recognition circuit 12 is formed of a camera or the like, and a recognition circuit 12 is connected to the light receiver 1. The recognition circuit 12 is connected to a control circuit 11 that adjusts the intensity of illumination light emitted from the light source 2 by changing the voltage or current of the light source 2. Has been done. The upper CPU 4 is connected to the control circuit 11, and the memory 13 is connected to the upper CPU 4. An identifier 8 made of a material having a reflectance different from that of the semiconductor wafer 7 is formed on the surface of the semiconductor wafer 7.

The memory 13 connected to the host CPU 4 stores process information such as manufacturing conditions for each manufacturing process and information such as an ID number of a semiconductor wafer to be processed. That is, information on the surface of the semiconductor wafer 7 from which the identifier 8 is to be recognized, and further information on the reflectance of the identifier 8 in each manufacturing process and the reflectance of the surface of the semiconductor wafer 7 where the identifier 8 does not exist are stored. . The memory 13 and the host CPU 4 form a host computer system. Further, the light source 2 and the projection lens system 3 serve as an illuminating means, and the recognition circuit 12 serves as a recognizing means.
The control circuit 11 forms control means.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG. First, the control circuit 11
In step S11, the information of the surface of the semiconductor wafer 7 stored in the memory 13 is received following the read command from the upper CPU 4, and the voltage of the light source 2 is adjusted so that the illumination intensity is preset for the information. Alternatively, adjust the current. As a result, the received light intensity of the reflected light from the semiconductor wafer 7 entering the light receiver 1 is set to a predetermined intensity.

In this state, the image pickup operation is performed as follows. The semiconductor wafer 7 is formed by the light source 2 and the projection lens system 3.
The surface of is illuminated obliquely, and the reflected light from the semiconductor wafer 7 is imaged on the light receiver 1 by the imaging lens 6. At this time, since the reflectance of the identifier 8 is different from the reflectance of the surface of the semiconductor wafer 7 where the identifier 8 does not exist, the incident lights 9a and 9b incident on the surface of the semiconductor wafer 7 through the light projecting lens system 3. And 9c, the reflected light 10b from the identifier 8 and the reflected light 10a from a portion where the identifier 8 does not exist.
And 10c, there is a difference in intensity. The identifier 8 such as a character or a symbol is imaged by this difference in intensity.

The recognition circuit 12 inputs the image from the light receiver 1 in step S12, and recognizes the identifier 8 composed of characters or symbols from the input image in step S13. Identifier 8
Is recognized (step S14), the recognition circuit 5 sets the recognition result in step S15 and transmits it to the upper CPU 4 via the control circuit 11. On the other hand, if the identification 8 is not successfully recognized in step S14,
In step S16, an error code is set and transmitted to the upper CPU 4.

As described above, in the first embodiment, step S
In 11, the intensity of the illumination light emitted from the light source 2 is adjusted according to the state of the surface of the semiconductor wafer 7 to be recognized, so trial and error by diaphragm adjustment is repeated as in the conventional method shown in FIG. It is not necessary and the identifier 8 can be recognized in a short time.

Although the intensity of the illumination light is controlled by adjusting the voltage or current of the light source 2 in the first embodiment, the light amount adjusting mechanism such as a diaphragm is provided in the light projecting lens system 3, and this light amount adjusting mechanism is provided. Thus, the intensity of the illumination light with which the semiconductor wafer 7 is irradiated can be controlled.

The identifier can also be represented by shaving the surface of the semiconductor wafer 7 to form a recess, but in this case as well, reflection from the identifier depends on the angle of the surface in the recess forming the identifier. Since an intensity difference occurs between the light and the reflected light from other portions, the identifier can be recognized in the same manner.

Example 2. FIG. 3 shows a semiconductor wafer ID recognition device according to the second embodiment. This device is different from the recognition device of the first embodiment shown in FIG. 1 in that a control circuit 21 is provided instead of the control circuit 11, a diaphragm 19 is arranged between the semiconductor wafer 7 and the light receiver 1, and the diaphragm 19 is A diaphragm driving step motor 22 for adjusting the aperture is connected to the control circuit 21.

When the control circuit 21 receives the information on the surface of the semiconductor wafer 7 from the upper CPU 4, the received light intensity of the reflected light from the semiconductor wafer 7 incident on the light receiver 1 is set in advance for the information. Then, the aperture driving step motor 22 is driven to adjust the aperture of the aperture 19. The light source 2 and the projection lens system 3 always emit illumination light of a predetermined intensity. After that, image input and recognition of the identifier 8 are performed in the same manner as in the first embodiment.

In this way, by adjusting the aperture of the diaphragm 19 arranged between the semiconductor wafer 7 and the light receiver 1, the same effect as that of the first embodiment can be obtained. In particular, since it is not necessary to adjust the intensity of the illumination light emitted from the illumination means, the light source 2 and the projection lens system 3 can have a simpler configuration.

A combination of the above-described first and second embodiments, the control circuit adjusts the intensity of the illumination light by the light source 2 or the light projecting lens system 3, and the diaphragm arranged between the semiconductor wafer 7 and the light receiver 1. It can also be configured to adjust the aperture of 19. The same effect as in Examples 1 and 2 can be obtained.

In the first embodiment, the control circuit 11 uses the memory 1
3 receives the process information for each manufacturing process stored in 3 and information about the surface of the semiconductor wafer 7 such as the ID number of the semiconductor wafer, and controls the light source 2 so that the illumination intensity is preset for this information. Controlled, but not limited to this. For example, the upper CPU 4 may calculate the illumination intensity corresponding to the information on the surface of the semiconductor wafer 7, and the control circuit 11 may directly receive the illumination intensity data from the upper CPU 4.

Further, as for the second embodiment, the upper CPU 4
Calculates the received light intensity at the photodetector 1 corresponding to the information about the surface of the semiconductor wafer 7, and the control circuit 21 directly receives the data about the received light intensity from the upper CPU 4,
The aperture driving step motor 22 may be driven based on the data.

In each of the above-described embodiments, the illumination light is irradiated from obliquely above the semiconductor wafer 7, but it is also possible to irradiate the semiconductor wafer 7 vertically or at an angle close to vertical.

In the first embodiment, the method of capturing an image by the intensity difference between the reflected light from the identifier 8 formed on the semiconductor wafer 7 and the reflected light from the portion where the identifier 8 does not exist has been described. It is also possible to cut off all or most of the reflected light from the non-exposed portion and capture the image of the identifier 8 by the reflected light from the identifier 8. Identifier 8
Of the semiconductor wafer 7 where the reflectivity of the part where the identifier 8 does not exist
It is effective when it is larger than the reflectance of the surface. Conversely, all or most of the reflected light from the identifier 8 may be cut, and the image of the identifier 8 may be captured by the reflected light from the portion where the identifier 8 does not exist. This is effective when the reflectance of the identifier 8 is smaller than the reflectance of the surface of the semiconductor wafer 7 where the identifier 8 does not exist.

[0038]

As described above, according to claim 1 of the present invention.
The semiconductor wafer ID recognition device according to the above-mentioned is a host computer system having information about a semiconductor wafer to be processed and information about each manufacturing process, an illuminating means for illuminating the surface of the semiconductor wafer, and a reflected light from the semiconductor wafer. A light receiver for receiving, a recognition means for processing an image from the light receiver to recognize an identifier formed on the surface of a semiconductor wafer, and information for each manufacturing process from a host computer system and the light receiver based on the information. Since the control means for controlling the intensity of the reflected light received by is provided, the identifier can be surely recognized in a short time.

According to a second aspect of the semiconductor wafer ID recognition apparatus of the first aspect, the control means controls the intensity of the illumination light emitted from the illumination means, so that the received light intensity is adjusted without using a diaphragm. It can be performed.

According to a third aspect of the present invention, there is provided a semiconductor wafer ID recognition device according to the first aspect, wherein the control means adjusts the aperture arranged between the semiconductor wafer and the light receiver and the aperture of the aperture. Since the diaphragm driving means is included, it is possible to easily adjust the received light intensity even when using an illuminating means in which it is difficult to control the intensity of the illuminating light.

A semiconductor wafer ID recognition method according to a fourth aspect of the present invention receives information regarding a semiconductor wafer to be processed for each manufacturing process, and receives reflected light having an intensity preset for the information regarding the semiconductor wafer. As described above, by illuminating the surface of the semiconductor wafer and receiving reflected light from the semiconductor wafer, the image of the identifier formed on the surface of the semiconductor wafer is captured, and the captured image is processed to recognize the identifier. The identifier can be surely recognized in a short time.

A semiconductor wafer ID recognition method according to a fifth aspect of the present invention is the method of the fourth aspect, wherein the intensity of the illumination light for illuminating the semiconductor wafer is adjusted to set the received intensity of the reflected light to the set intensity. It is possible to adjust the received light intensity without using it.

A semiconductor wafer ID recognition method according to a sixth aspect of the present invention is the method of the fourth aspect, wherein the received light intensity of the reflected light is set to a set intensity by narrowing the reflected light from the semiconductor wafer, so that the intensity of the illumination light is controlled. Even if it is difficult to adjust the intensity, the received light intensity can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a semiconductor wafer ID according to a first embodiment of the present invention.
It is a block diagram which shows the structure of a recognition apparatus.

FIG. 2 is a flowchart showing the operation of the first embodiment.

FIG. 3 is a block diagram showing a configuration of a semiconductor wafer ID recognition device according to a second embodiment.

FIG. 4 is a block diagram showing a configuration of a conventional semiconductor wafer ID recognition device.

5 is a flowchart showing the operation of the apparatus of FIG.

[Explanation of symbols]

1 light receiver, 2 light source, 3 light emitting lens system, 4 upper C
PU, 6 imaging lens, 7 semiconductor wafer, 8 identifier, 11, 21 control circuit, 12 recognition circuit, 13 memory, 19 diaphragm, 22 diaphragm step motor.

Claims (6)

[Claims] 1. A host computer system having information about a semiconductor wafer to be processed and information about each manufacturing process, an illuminating means for illuminating the surface of the semiconductor wafer, and a light receiver for receiving reflected light from the semiconductor wafer. Recognizing means for recognizing an identifier formed on the surface of a semiconductor wafer by processing an image from the photodetector, and receiving information from the host computer system for each manufacturing process, and the photodetector based on the information. A semiconductor wafer ID recognition device comprising: a control unit that controls the intensity of reflected light received. 2. The semiconductor wafer ID recognition device according to claim 1, wherein the control unit controls the intensity of the illumination light emitted from the illumination unit. 3. The control means includes a diaphragm arranged between the semiconductor wafer and the photodetector, and diaphragm driving means for adjusting the aperture of the diaphragm. The semiconductor wafer ID recognition device described in 1. 4. Information on a semiconductor wafer to be processed is received for each manufacturing process, and the surface of the semiconductor wafer is illuminated so that reflected light having an intensity preset for the information on the semiconductor wafer is received. A semiconductor wafer ID recognition method characterized in that an image of an identifier formed on the surface of a semiconductor wafer is captured by receiving reflected light from the semiconductor wafer, and the captured image is processed to recognize the identifier. 5. The semiconductor wafer ID recognition method according to claim 4, wherein the received light intensity of the reflected light is set as the set intensity by adjusting the intensity of the illumination light that illuminates the semiconductor wafer. 6. The semiconductor wafer ID recognition method according to claim 4, wherein the received light intensity of the reflected light is set as the set intensity by narrowing the reflected light from the semiconductor wafer.