WO2008084982A1 - Apparatus for optically recognizing wafer indentification code - Google Patents
Apparatus for optically recognizing wafer indentification code Download PDFInfo
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- WO2008084982A1 WO2008084982A1 PCT/KR2008/000135 KR2008000135W WO2008084982A1 WO 2008084982 A1 WO2008084982 A1 WO 2008084982A1 KR 2008000135 W KR2008000135 W KR 2008000135W WO 2008084982 A1 WO2008084982 A1 WO 2008084982A1
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- wafer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67242—Apparatus for monitoring, sorting or marking
- H01L21/67294—Apparatus for monitoring, sorting or marking using identification means, e.g. labels on substrates or labels on containers
Definitions
- the present invention relates to an apparatus for recognizing a wafer identification code by using a wafer prober, and more particularly, to an apparatus for recognizing a wafer identification code capable of accurately recognizing a wafer identification code from a wafer image by controlling an illumination angle of an illumination unit and capturing a clear image of the wafer.
- a wafer prober station is one of EDS examination devices used for a process of manufacturing a semiconductor which electrically tests whether dies in a wafer state before packaging a semiconductor chip formed on a semiconductor wafer normally operate by contacting an examination probe to a die in the semiconductor wafer and applying an electrical signal to the probe.
- the aforementioned wafer prober is a device for reducing a loss of raw-material and time to be used for a subsequent packaging process and a packaging test process and the like by early removing a defective die by directly contacting and testing a pad of a wafer.
- FIG. 1 is a front view illustrating a wafer prober station. Referring FIG.
- the wafer prober station is constructed with a wafer loader for conveying a semiconductor wafer from a FOUP or cassette to a position to be tested or onto a chuck, a stage for enabling a wafer to contact a probe card by precisely conveying the wafer so as to test the wafer, and a tester for examining the wafer located on the chuck on the stage.
- a probe card is mounted on a header of the tester. It is checked whether a chip is defective by applying an electrical signal to the chip on the wafer by using the probe card and measuring the result.
- the wafer prober station needs to recognize a type, a lot number, and a wafer identification code of the wafer to be tested. For this, a unique identification code is allocated to each wafer. Each identification code is displayed at a predetermined position by using an etching or a printing technique on a flat surface or a predetermined position on the flat surface. A technique of recognizing the wafer identification code by using a camera is referred to as optical character recognition (hereinafter, abbreviated to 'OCR').
- optical character recognition hereinafter, abbreviated to 'OCR'
- FIG. 2 illustrates a schematic structure of an OCR apparatus of a wafer prober station according to a conventional technique.
- the conventional OCR apparatus is combined with a camera module and an illumination module.
- a procedure of identifying the wafer identification code (ID) by using the OCR apparatus with the aforementioned structure will be briefly described.
- a flat/notch of the wafer is recognized by using an optical sensor and a centering camera by moving or rotating the wafer located on a wafer seat by controlling a motor and a motor driving unit.
- a charge coupled device (CCD) camera for identifying a wafer ID captures an area in which the wafer ID is printed and recognizes the wafer ID by processing and analyzing the captured image.
- CCD charge coupled device
- a reflection angle of illumination light from the wafer surface or an amount of reflected light are different depending on a method of processing a surface on which the wafer identification code is printed or a method of printing the wafer identification code.
- the wafer identification code may not be recognized, if a type of a wafer is changed.
- the present invention provides an apparatus for recognizing a wafer identification code capable of accurately recognizing the wafer identification code by adjusting an angle of an illumination unit and an amount of light provided to a surface of a wafer.
- the present invention also provides an apparatus for recognizing a wafer identification code capable of accurately recognizing the wafer identification code by acquiring a plurality of images by using illumination units with different characteristics, composing the plurality of images acquired by using the different illumination units, and processing the composition image.
- an apparatus for recognizing a wafer identification code displayed on a surface of a wafer comprising: a camera unit capturing an image of a predetermined position of the wafer; a plurality of illumination units illuminating the surface of the wafer to be examined when the camera unit takes the image; a plurality of motors respectively connected to the plurality of illumination units, the plurality of motors rotating or moving the plurality of illumination units; a plurality of motor driving units respectively connected to the plurality of motors, the plurality of motor driving units respectively driving the motors; and a control unit controlling the motor driving units, the camera unit, and the illumination units and recognizing the wafer identification code by using images provided by the camera unit, wherein the control unit enables an image pickup area of the wafer to be accurately illuminated by controlling illumination angles of the illumination units by transmitting a driving signal for the motors to the motor driving unit.
- the control unit may recognize the wafer identification code by processing the image provided
- an apparatus for recognizing a wafer identification code displayed on a surface of a wafer comprising: a camera unit capturing an image of a predetermined position of the wafer; at least one illumination unit illuminating the surface of the wafer to be examined when the camera unit takes the image; a control unit controlling operations of the camera unit and the illumination units and recognizing the wafer identification code by using the images provided by the camera; a diffusion plate of which surface is processed so that light is diffused, the diffusion plate located in front of the illumination unit; and a reflective plate reflecting light of the illumination units to an image pickup area of the wafer provided through the diffusion plate, wherein the light provided by the illumination unit is diffused by the diffusion plate and provided to an image pickup area of the wafer.
- control unit may acquire a plurality of images of the wafer by controlling the illumination unit and the camera unit, generate a composition image by composing the acquired images, and recognize the wafer identification code by using the composition image, and the plurality of images may be taken in different illumination environments.
- control unit may compare image data of each pixel of the composition image with a predetermined reference value. If image data of a pixel is greater than the reference value, the image data of the pixel is set to 1 I 1 . If image data of a pixel is less than the reference value, the image data of the pixel is set to 1 O'.
- the composition image is changed to a binary image represented by binary data. The wafer identification code is recognized by using the changed binary image.
- FIG. 5 illustrates images captured by adjusting angles of illumination units according to an embodiment by using the apparatus for recognizing the wafer identification code and an image captured without adjusting the angles of the illumination units according to a conventional technique.
- (a) is an image captured without adjusting an illumination angle of the illumination unit 312 of FIG. 3
- (b) and (c) are images captured by adjusting the illumination angle of the illumination unit 312.
- the captured image is clear and it is possible to easily recognize the wafer identification code by adjusting the illumination angle of the illumination unit according to the embodiment of the present invention.
- FIGS. 6 to 9 illustrate images captured by using conventional basic illumination units and images captured by using a diffusion plate and a reflective plate according to an embodiment of the present invention.
- (a) isan image according to a conventional technique
- (b) is an image according to the embodiment of the present invention.
- an image captured in a state where light of the illumination unit is scattered by using the diffusion plate and the reflective plate according to the embodiment is clear. As a result, it is possible to easily recognize the wafer identification code.
- (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to damage such as a scratch in the wafer identification code
- (b) is an image obtained by capturing the wafer identification code by passing through the scratch by using the diffusion plate and the reflective plate.
- (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to a wafer pattern since the wafer identification code overlaps the wafer pattern
- (b) is an image obtained by capturing a state in which only the wafer identification code is emphasized without influence of a surrounding pattern by using the diffusion plate and the reflective plate according to the embodiment of the present invention.
- (a) is an image obtained by capturing a state in which a belt on the surface of the wafer overlaps the wafer identification code, and letters of the wafer identification code are confused as other letters
- (b) is an image obtained by capturing a state in which only the wafer identification code is emphasized by reducing the influence of the belt on the surface by using the diffusion plate and the reflective plate according to the embodiment of the present invention.
- FIG. 9 (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to fingerprints when there are the fingerprints on the wafer identification code, and (b) is an image obtained by capturing the wafer identification code by passing through the fingerprints on the wafer identification code by using the diffusion plate and the reflective plate according to the embodiment of the present invention.
- FIG. 1 illustrates an entire structure of a general wafer prober station.
- FIG. 2 illustrates a schematic structure of an apparatus for recognizing a wafer identification code according to a conventional technique.
- FIG. 3 illustrates a schematic structure of an apparatus for recognizing a wafer identification code according to a first embodiment of the present invention.
- FIG. 4 is a schematic block diagram illustrating the apparatus for recognizing a wafer identification code according to the first embodiment of the present invention.
- FIG. 5 illustrates images captured by adjusting angles of illumination units according to an embodiment of the present invention and an image captured without adjusting the angles of the illumination units according to a conventional technique.
- FIGS. 6 to 9 illustrate images captured by using a diffusion plate and a reflective plate according to an embodiment of the present invention and images captured according to a conventional technique.
- FIG. 10 illustrates images taken in environments in which angles and positions of illumination units with respect to the same wafer by using an apparatus for recognizing a wafer identification code according to an embodiment.
- FIG. 11 illustrates an example of an image obtained by changing a black and white image to a new binary image represented by black and white colors by using the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment of the present invention.
- FIG. 3 illustrates a schematic structure of an apparatus 30 for recognizing a wafer identification code according to a first embodiment of the present invention.
- FIG. 4 is a schematic block diagram illustrating only essential elements of the apparatus 30 for recognizing the wafer identification code according to the first embodiment of the present invention. Now, a structure and an operation of the apparatus 30 for recognizing a wafer identification code according to the first embodiment will be described in detail with reference to FIG. 3 and 4.
- the apparatus 30 for recognizing a wafer identification code serves to recognize a wafer identification code displayed at a predetermined position on a surface of the wafer.
- the apparatus 30 for recognizing the wafer identification code includes a camera unit 300, at least one illumination unit 310 or 312, motor 320 or 324, a motor driving unit 330, a control unit 340 for controlling an entire operation, a reflective plate 350, and a diffusion plate 360.
- the camera unit 300 captures an image of a predetermined position of the wafer and provides the captured image to the control unit 340.
- the illumination unit 310 or 312 is illumination lamp for illuminating the surface of the wafer to be examined when the camera unit takes an image.
- the apparatus for recognizing a wafer identification code includes a plurality of illumination units.
- the motor 320 or 324 connected to the illumination unit 310 or 312 rotates or moves the illumination unit.
- the motor 320 or 324 are driven by the motor driving unit 330.
- the motors 320 and 324 according to the first embodiment may employ step motors.
- the motor driving unit 330 drives the motors 320 and 324 according to a driving signal transmitted from the control unit 340. Accordingly, the illumination unit 310 or 312 rotated or moved by the motor that is driven according to the driving signal provided by the control unit 340. An illumination angle and position are adjusted by the control unit.
- the control unit 340 entirely controls operations of modules of the apparatus for recognizing the wafer identification code.
- the control unit 340 controls operations of the motor driving unit, the camera unit, and the illumination unit.
- the control unit 340 recognizes the wafer identification code by processing images of the wafer provided by the camera unit and analyzing the processed images.
- control unit 340 enables an image pickup area of the wafer that is to be photographed by the camera unit to be accurately illuminated by controlling angles and positions of the illumination units by transmitting signals for driving the motors to the motor driving unit.
- the diffusion plate 350 has a surface treatment so that light incident onto the surface is diffused.
- the diffusion plate 350 is located in front of the illumination unit. Accordingly, light provided by the illumination unit is diffused by the diffusion plate 350.
- the reflective plate 360 reflects light of the illumination unit which is provided through the diffusion plate 350 to the image pickup area of the wafer.
- the reflective plate has a curved surface with a predetermined curvature.
- the light provided by the illumination unit is scattered by the diffusion plate 350 and the reflective plate 360. Accordingly, it is possible to remove noise such as scratches or fingerprints that may be included in the image captured by the camera unit.
- the apparatus for recognizing the wafer identification code according to the second embodiment can accurately recognize a wafer identification code by acquiring a plurality of images in illumination environments with different features, composing the plurality of images, and analyzing the composition image.
- a structure of the apparatus for recognizing the wafer identification code according to the second embodiment is the same as that of the first embodiment except an operation of a control unit. Accordingly, only the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment will be described. Since the other elements are the same as those of the first embodiment, description on the other elements wi 11 be omitted.
- FIG. 10 illustrates images taken by the apparatus for recognizing a wafer identification code according to the second embodiment of the present invention in different environments in which angles and positions of illumination units are different with respect to the same wafer.
- states of the wafer identification code in the image are different depending on positions and angles of the illumination units.
- (a) is an image with a vertical scratch in the wafer identification code
- (b) is an image with a horizontal scratch in the wafer identification code
- (c) is an image with minute vertical and horizontal scratches.
- the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment provides a first driving signal for adjusting angles and positions of the illumination units to the motor driving unit.
- the motor driving unit drives the motors connected to the illumination units according to the first driving signal.
- the camera unit takes a first image of the wafer and transmits the first image to the control unit.
- the control unit provides a second driving signal for changing the angles and positions of the illumination units to the motor driving unit.
- the motor driving unit drives the motors connected to the illumination units according to the second driving signal and adjusts the positions and angles of the illumination units, again.
- the camera unit takes a second image of the wafer and transmits the second image to the control unit.
- the control unit acquires a plurality of images of the wafer by repeatedly performing the aforementioned procedure and generates a composition image by composing the acquired images.
- the method of composing the acquired plurality of images adds image datum of pixels corresponding all the images and obtains a mean value of the image datum.
- another method of composing a plurality of images which is widely used in the art may be used.
- the control unit removes noise from the composition image by applying a predetermined algorithm and generates a new image in which only the wafer identification code is clearly displayed.
- a reference value is set. Image data of each pixel of the composition image is compared with the reference value. If the image data of the corresponding pixel is greater than the reference value, the image data of the pixel is changed to 1 I'. If the image data of the corresponding pixel is less than the reference value, the image data of the pixel is changed to 1 O'.
- the composition image is changed to a binary image represented by binary data by performing the aforementioned procedure with respect to all the pixels. If it is difficult to accurately recognize the wafer identification code from the binary image, the reference value is modified, a binary image is generated from the composition image by using the modified reference value, and the wafer identification code is recognized from the binary image.
- FIG. 11 illustrate an example of an image obtained by changing a black and white image to a new binary image represented by black and white colors by using the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment of the present invention.
- the control unit recognizes the wafer identification code by analyzing the newly generated binary image.
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Abstract
An apparatus for recognizing a wafer identification code is provided. The apparatus for recognizing the wafer identification code includes a camera unit picking up an image of a predetermined area of a wafer on which the wafer identification code is printed, illumination units illuminating the wafer when the camera unit takes the image, motors connected to the illumination units, the motors rotating and moving the illumination units, a motor driving unit, a control unit controlling entire operations, a diffusion plate of which surface is processed so that incident light is diffused, the diffusion plate located in front of the illumination unit, and a reflective plate reflecting light of the illumination unit and providing the reflected light to the image pickup area of the wafer. It is possible to obtain a clear image by controlling illumination angles of the illumination units and uniformly illuminating the image pickup area by using the diffusion plate and the reflective plate. Accordingly, it is possible to accurately recognize the wafer identification code.
Description
[DESCRIPTION] [Invention Title]
APPARATUS FOR OPTICALLY RECOGNIZING WAFER IDENTIFICATION CODE [Technical Field]
The present invention relates to an apparatus for recognizing a wafer identification code by using a wafer prober, and more particularly, to an apparatus for recognizing a wafer identification code capable of accurately recognizing a wafer identification code from a wafer image by controlling an illumination angle of an illumination unit and capturing a clear image of the wafer. [Background Art]
In general, a wafer prober station is one of EDS examination devices used for a process of manufacturing a semiconductor which electrically tests whether dies in a wafer state before packaging a semiconductor chip formed on a semiconductor wafer normally operate by contacting an examination probe to a die in the semiconductor wafer and applying an electrical signal to the probe. The aforementioned wafer prober is a device for reducing a loss of raw-material and time to be used for a subsequent packaging process and a packaging test process and the like by early removing a defective die by directly contacting and testing a pad of a wafer.
FIG. 1 is a front view illustrating a wafer prober station. Referring FIG. 1, the wafer prober station is constructed with a wafer loader for conveying a semiconductor wafer from a FOUP or cassette to a position to be tested or onto a chuck, a stage for enabling a wafer to contact a probe card by precisely conveying the wafer so as to test the wafer, and a tester for examining the wafer located on the chuck on the stage. A probe card is mounted on a header of the tester. It is checked whether a chip is defective by applying an electrical signal to the chip on the wafer by using the probe card and measuring the result.
On the other hand, the wafer prober station needs to recognize a type, a lot number, and a wafer identification code of the wafer to be tested. For this, a unique identification code is allocated to each wafer. Each identification code is displayed at a predetermined position by using an etching or a printing technique on a flat surface or a predetermined position on the flat surface. A technique of recognizing the wafer identification code by using a camera is referred to as optical character recognition (hereinafter, abbreviated to 'OCR').
FIG. 2 illustrates a schematic structure of an OCR apparatus of
a wafer prober station according to a conventional technique. Referring to FIG. 2, the conventional OCR apparatus is combined with a camera module and an illumination module. A procedure of identifying the wafer identification code (ID) by using the OCR apparatus with the aforementioned structure will be briefly described. First, a flat/notch of the wafer is recognized by using an optical sensor and a centering camera by moving or rotating the wafer located on a wafer seat by controlling a motor and a motor driving unit. Next, a charge coupled device (CCD) camera for identifying a wafer ID captures an area in which the wafer ID is printed and recognizes the wafer ID by processing and analyzing the captured image.
However, a reflection angle of illumination light from the wafer surface or an amount of reflected light are different depending on a method of processing a surface on which the wafer identification code is printed or a method of printing the wafer identification code. As a result, in the conventional OCR device with a constant position and a constant angle of illumination, the wafer identification code may not be recognized, if a type of a wafer is changed.
[Disclosure]
[Technical Problem]
The present invention provides an apparatus for recognizing a wafer identification code capable of accurately recognizing the wafer identification code by adjusting an angle of an illumination unit and an amount of light provided to a surface of a wafer.
The present invention also provides an apparatus for recognizing a wafer identification code capable of accurately recognizing the wafer identification code by acquiring a plurality of images by using illumination units with different characteristics, composing the plurality of images acquired by using the different illumination units, and processing the composition image. [Technical Solution]
According to an aspect of the present invention, there is provided an apparatus for recognizing a wafer identification code displayed on a surface of a wafer, the apparatus comprising: a camera unit capturing an image of a predetermined position of the wafer; a plurality of illumination units illuminating the surface of the wafer to be examined when the camera unit takes the image; a plurality of motors respectively connected to the plurality of illumination units, the plurality of motors rotating or moving the plurality of illumination units; a plurality of motor driving units
respectively connected to the plurality of motors, the plurality of motor driving units respectively driving the motors; and a control unit controlling the motor driving units, the camera unit, and the illumination units and recognizing the wafer identification code by using images provided by the camera unit, wherein the control unit enables an image pickup area of the wafer to be accurately illuminated by controlling illumination angles of the illumination units by transmitting a driving signal for the motors to the motor driving unit. In the above aspect of the present invention, the control unit may recognize the wafer identification code by processing the image provided by the camera unit and analyzing the processed image.
According to another aspect of the present invention, there is provided an apparatus for recognizing a wafer identification code displayed on a surface of a wafer, the apparatus comprising: a camera unit capturing an image of a predetermined position of the wafer; at least one illumination unit illuminating the surface of the wafer to be examined when the camera unit takes the image; a control unit controlling operations of the camera unit and the illumination units and recognizing the wafer identification code by using the images provided by the camera; a diffusion plate of which surface is
processed so that light is diffused, the diffusion plate located in front of the illumination unit; and a reflective plate reflecting light of the illumination units to an image pickup area of the wafer provided through the diffusion plate, wherein the light provided by the illumination unit is diffused by the diffusion plate and provided to an image pickup area of the wafer.
In the above aspect of the present invention, the control unit may acquire a plurality of images of the wafer by controlling the illumination unit and the camera unit, generate a composition image by composing the acquired images, and recognize the wafer identification code by using the composition image, and the plurality of images may be taken in different illumination environments.
In addition, the control unit may compare image data of each pixel of the composition image with a predetermined reference value. If image data of a pixel is greater than the reference value, the image data of the pixel is set to 1I1. If image data of a pixel is less than the reference value, the image data of the pixel is set to 1O'. The composition image is changed to a binary image represented by binary data. The wafer identification code is recognized by using the changed binary image.
[Advantageous Effects]
FIG. 5 illustrates images captured by adjusting angles of illumination units according to an embodiment by using the apparatus for recognizing the wafer identification code and an image captured without adjusting the angles of the illumination units according to a conventional technique. In FIG. 5, (a) is an image captured without adjusting an illumination angle of the illumination unit 312 of FIG. 3, and (b) and (c) are images captured by adjusting the illumination angle of the illumination unit 312. In FIG. 5, the captured image is clear and it is possible to easily recognize the wafer identification code by adjusting the illumination angle of the illumination unit according to the embodiment of the present invention.
FIGS. 6 to 9 illustrate images captured by using conventional basic illumination units and images captured by using a diffusion plate and a reflective plate according to an embodiment of the present invention. In FIGS. 6 to 9, (a) isan image according to a conventional technique, and (b)is an image according to the embodiment of the present invention. In FIGS. 6 to 9, an image captured in a state where light of the illumination unit is scattered by using the diffusion plate and the reflective plate according to the embodiment
is clear. As a result, it is possible to easily recognize the wafer identification code.
*17In FIG. 6, (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to damage such as a scratch in the wafer identification code, and (b) is an image obtained by capturing the wafer identification code by passing through the scratch by using the diffusion plate and the reflective plate.
In FIG. 7, (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to a wafer pattern since the wafer identification code overlaps the wafer pattern, and (b) is an image obtained by capturing a state in which only the wafer identification code is emphasized without influence of a surrounding pattern by using the diffusion plate and the reflective plate according to the embodiment of the present invention.
In FIG. 8, (a) is an image obtained by capturing a state in which a belt on the surface of the wafer overlaps the wafer identification code, and letters of the wafer identification code are confused as other letters, and (b) is an image obtained by capturing a
state in which only the wafer identification code is emphasized by reducing the influence of the belt on the surface by using the diffusion plate and the reflective plate according to the embodiment of the present invention.
In FIG. 9, (a) is an image obtained by capturing a state in which the wafer identification code is unrecognizable due to fingerprints when there are the fingerprints on the wafer identification code, and (b) is an image obtained by capturing the wafer identification code by passing through the fingerprints on the wafer identification code by using the diffusion plate and the reflective plate according to the embodiment of the present invention. [Description of Drawings]
FIG. 1 illustrates an entire structure of a general wafer prober station.
FIG. 2 illustrates a schematic structure of an apparatus for recognizing a wafer identification code according to a conventional technique.
FIG. 3 illustrates a schematic structure of an apparatus for recognizing a wafer identification code according to a first embodiment of the present invention.
FIG. 4 is a schematic block diagram illustrating the apparatus for recognizing a wafer identification code according to the first embodiment of the present invention.
FIG. 5 illustrates images captured by adjusting angles of illumination units according to an embodiment of the present invention and an image captured without adjusting the angles of the illumination units according to a conventional technique.
FIGS. 6 to 9 illustrate images captured by using a diffusion plate and a reflective plate according to an embodiment of the present invention and images captured according to a conventional technique.
FIG. 10 illustrates images taken in environments in which angles and positions of illumination units with respect to the same wafer by using an apparatus for recognizing a wafer identification code according to an embodiment.
FIG. 11 illustrates an example of an image obtained by changing a black and white image to a new binary image represented by black and white colors by using the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment of the present invention. [Best Mode]
First Embodiment
Hereinafter, an apparatus for recognizing a wafer identification code according to a first embodiment will be described in detail with reference to the attached drawings. FIG. 3 illustrates a schematic structure of an apparatus 30 for recognizing a wafer identification code according to a first embodiment of the present invention. FIG. 4 is a schematic block diagram illustrating only essential elements of the apparatus 30 for recognizing the wafer identification code according to the first embodiment of the present invention. Now, a structure and an operation of the apparatus 30 for recognizing a wafer identification code according to the first embodiment will be described in detail with reference to FIG. 3 and 4.
Referring to FIGS. 3 and 4, the apparatus 30 for recognizing a wafer identification code serves to recognize a wafer identification code displayed at a predetermined position on a surface of the wafer. The apparatus 30 for recognizing the wafer identification code includes a camera unit 300, at least one illumination unit 310 or 312, motor 320 or 324, a motor driving unit 330, a control unit 340 for controlling an entire operation, a reflective plate 350, and a diffusion plate 360.
The camera unit 300 captures an image of a predetermined position of the wafer and provides the captured image to the control unit 340.
The illumination unit 310 or 312 is illumination lamp for illuminating the surface of the wafer to be examined when the camera unit takes an image. The apparatus for recognizing a wafer identification code includes a plurality of illumination units. The motor 320 or 324 connected to the illumination unit 310 or 312 rotates or moves the illumination unit. The motor 320 or 324 are driven by the motor driving unit 330. On the other hand, the motors 320 and 324 according to the first embodiment may employ step motors. The motor driving unit 330 drives the motors 320 and 324 according to a driving signal transmitted from the control unit 340. Accordingly, the illumination unit 310 or 312 rotated or moved by the motor that is driven according to the driving signal provided by the control unit 340. An illumination angle and position are adjusted by the control unit.
The control unit 340 entirely controls operations of modules of the apparatus for recognizing the wafer identification code. The control unit 340 controls operations of the motor driving unit, the
camera unit, and the illumination unit. In addition, the control unit 340 recognizes the wafer identification code by processing images of the wafer provided by the camera unit and analyzing the processed images.
Specifically, the control unit 340 according to the first embodiment enables an image pickup area of the wafer that is to be photographed by the camera unit to be accurately illuminated by controlling angles and positions of the illumination units by transmitting signals for driving the motors to the motor driving unit.
The diffusion plate 350 has a surface treatment so that light incident onto the surface is diffused. The diffusion plate 350 is located in front of the illumination unit. Accordingly, light provided by the illumination unit is diffused by the diffusion plate 350.
The reflective plate 360 reflects light of the illumination unit which is provided through the diffusion plate 350 to the image pickup area of the wafer. The reflective plate has a curved surface with a predetermined curvature.
The light provided by the illumination unit is scattered by the diffusion plate 350 and the reflective plate 360. Accordingly, it is
possible to remove noise such as scratches or fingerprints that may be included in the image captured by the camera unit.
Second Embodiment
Hereinafter, an apparatus for recognizing a wafer identification code according to a second embodiment will be described in detail with reference to the attached drawings. The apparatus for recognizing the wafer identification code according to the second embodiment can accurately recognize a wafer identification code by acquiring a plurality of images in illumination environments with different features, composing the plurality of images, and analyzing the composition image. A structure of the apparatus for recognizing the wafer identification code according to the second embodiment is the same as that of the first embodiment except an operation of a control unit. Accordingly, only the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment will be described. Since the other elements are the same as those of the first embodiment, description on the other elements wi 11 be omitted.
FIG. 10 illustrates images taken by the apparatus for recognizing a wafer identification code according to the second
embodiment of the present invention in different environments in which angles and positions of illumination units are different with respect to the same wafer. In FIG. 10, states of the wafer identification code in the image are different depending on positions and angles of the illumination units. In FIG. 10, (a) is an image with a vertical scratch in the wafer identification code, (b) is an image with a horizontal scratch in the wafer identification code, and (c) is an image with minute vertical and horizontal scratches.
The control unit of the apparatus for recognizing the wafer identification code according to the second embodiment provides a first driving signal for adjusting angles and positions of the illumination units to the motor driving unit. The motor driving unit drives the motors connected to the illumination units according to the first driving signal. After the positions and the angles of the illumination units are adjusted, the camera unit takes a first image of the wafer and transmits the first image to the control unit.
The control unit provides a second driving signal for changing the angles and positions of the illumination units to the motor driving unit. The motor driving unit drives the motors connected to the illumination units according to the second driving signal and
adjusts the positions and angles of the illumination units, again. Next, the camera unit takes a second image of the wafer and transmits the second image to the control unit.
The control unit acquires a plurality of images of the wafer by repeatedly performing the aforementioned procedure and generates a composition image by composing the acquired images. In the present invention, the method of composing the acquired plurality of images adds image datum of pixels corresponding all the images and obtains a mean value of the image datum. However, another method of composing a plurality of images which is widely used in the art may be used.
Next, the control unit removes noise from the composition image by applying a predetermined algorithm and generates a new image in which only the wafer identification code is clearly displayed. Hereinafter, an example of the algorithm for generating the new image in the present invention will be described. First, a reference value is set. Image data of each pixel of the composition image is compared with the reference value. If the image data of the corresponding pixel is greater than the reference value, the image data of the pixel is changed to 1I'. If the image data of the corresponding pixel is less than the reference value, the image data of the pixel is changed
to 1O'. The composition image is changed to a binary image represented by binary data by performing the aforementioned procedure with respect to all the pixels. If it is difficult to accurately recognize the wafer identification code from the binary image, the reference value is modified, a binary image is generated from the composition image by using the modified reference value, and the wafer identification code is recognized from the binary image.
FIG. 11 illustrate an example of an image obtained by changing a black and white image to a new binary image represented by black and white colors by using the control unit of the apparatus for recognizing the wafer identification code according to the second embodiment of the present invention. The control unit recognizes the wafer identification code by analyzing the newly generated binary image.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. [Industrial Applicability]
The apparatus for recognizing a wafer identification code will be widely used for an apparatus which has to recognize a wafer identification code printed on a wafer.
Claims
[CLAIMS] [Claim 1]
An apparatus for recognizing a wafer identification code displayed on a surface of a wafer, the apparatus comprising: a camera unit capturing an image at a predetermined position of the wafer; a plurality of illumination units illuminating the surface of the wafer to be examined when the camera unit takes the image; a plurality of motors respectively connected to the plurality of illumination units, the plurality of motors rotating or moving the plurality of illumination units; a plurality of motor driving units respectively connected to the plurality of motors, the plurality of motor driving units respectively driving the motors; and a control unit controlling the motor driving units, the camera unit, and the illumination units and recognizing the wafer identification code by using images provided by the camera unit, wherein the control unit enables an image pickup area of the wafer to be accurately illuminated by controlling illumination angles of the illumination units by transmitting a driving signal for the
motors to the motor driving unit. [Claim 2]
The apparatus of claim 1, further comprising: a diffusion plate of which surface is processed so that incident light is diffused; and a reflective plate reflecting the light passing through the diffusion plate to the image pickup area of the wafer, wherein light provided from the illumination units is scattered and provided to the image pickup area of the wafer. [Claim 3]
The apparatus of claim 2, wherein the reflective plate has a curved surface. [Claim 4]
The apparatus of claim 2, wherein the diffusion plate is located in front of the illumination unit , and wherein the reflective plate is located at a position where the light passing through the diffusion plate is reflected to the image pickup area of the wafer. [Claim 5]
The apparatus of claim 1, wherein the diffusion plate is located in front of the illumination unit , and wherein a surface of the diffusion plate is processed so that light provided by the illumination unit is diffused. [Claim 6]
The apparatus of claim 1, further comprising a reflective plate reflecting light provided by the illumination unit to the image pickup area of the wafer. [Claim 7]
An apparatus for recognizing a wafer identification code displayed on a surface of a wafer, the apparatus comprising: a camera unit capturing an image of a predetermined position of the wafer; at least one illumination unit illuminating the surface of the wafer to be examined when the camera unit takes the image; a control unit controlling operation of the camera unit and the illumination units and recognizing the wafer identification code by using the images provided by the camera; and a diffusion plate of which surface is processed so that light is
diffused, the diffusion plate located in front of the illumination unit, wherein the light provided by the illumination unit is diffused by the diffusion plate and provided to an image pickup area of the wafer. [Claim 8]
The apparatus of claim 7, further comprising a reflective plate reflecting the light passing through the diffusion plate to the image pickup area of wafer, wherein the light provided through the illumination unit is scattered and provided to the image pickup area of the wafer. [Claim 9]
An apparatus for recognizing a wafer identification code displayed on a surface of a wafer, the apparatus comprising: a camera unit capturing an image of a predetermined position of the wafer; at least one illumination unit illuminating the surface of the wafer to be examined when the camera unit takes the image; a control unit controlling operation of the camera unit and the illumination units and recognizing the wafer identification code by
using the images provided by the camera; and a reflective plate reflecting light provided by the illumination unit to an image pickup area of the wafer, wherein the light provided by the illumination unit is scattered and provided to the image pickup area of the wafer. [Claim 10]
The apparatus of any one of claims 1 to 6, wherein the control unit acquires a plurality of images of the wafer by controlling the illumination unit and the camera unit, generates a composition image by composing the acquired images, and recognizes the wafer identification code by using the composition image, and wherein the plurality of images are taken in different illumination environments. [Claim 11]
The apparatus of claim 10, wherein the control unit compares image data of each pixel of the composition image with a predetermined reference value, wherein if image data of a pixel is greater than the reference value, the image data of the pixel is set to 'I1,
wherein if image data of a pixel is less than the reference value, the image data of the pixel is set to 1O', wherein the composition image is changed to a binary image represented by binary data, and wherein the wafer identification code is recognized by using the changed binary image.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020070003032A KR100789698B1 (en) | 2007-01-10 | 2007-01-10 | Apparatus for optically recognizing wafer indentification code |
| KR10-2007-0003032 | 2007-01-10 | ||
| KR1020080002394A KR100952694B1 (en) | 2008-01-09 | 2008-01-09 | Apparatus for optically recognizing wafer indentification code |
| KR10-2008-0002394 | 2008-01-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008084982A1 true WO2008084982A1 (en) | 2008-07-17 |
Family
ID=39608833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/KR2008/000135 WO2008084982A1 (en) | 2007-01-10 | 2008-01-09 | Apparatus for optically recognizing wafer indentification code |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2008084982A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103778421B (en) * | 2012-10-18 | 2018-01-12 | 中芯国际集成电路制造(上海)有限公司 | Read the method and Wafer identification reading device of Wafer identification |
| WO2018111227A1 (en) * | 2016-12-12 | 2018-06-21 | Intel Corporation | Systems, apparatuses, and methods for performing reticle inspections |
| CN110390325A (en) * | 2019-07-30 | 2019-10-29 | 深圳市技美智能自动化有限公司 | A kind of network centralization OCR identifying system and method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05133726A (en) * | 1991-11-13 | 1993-05-28 | Hitachi Ltd | Method and device for reading pattern |
| WO1995019012A1 (en) * | 1994-01-11 | 1995-07-13 | Hine Design Incorporated | Apparatus and methods for viewing identification marks on semiconductor wafers |
| JP2000205823A (en) * | 1999-01-11 | 2000-07-28 | Tokyo Electron Ltd | Method for identifying object and method and device for positioning the same |
| US20040206819A1 (en) * | 2002-10-01 | 2004-10-21 | Aisin Engineering Co., Ltd. | Code reader |
-
2008
- 2008-01-09 WO PCT/KR2008/000135 patent/WO2008084982A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05133726A (en) * | 1991-11-13 | 1993-05-28 | Hitachi Ltd | Method and device for reading pattern |
| WO1995019012A1 (en) * | 1994-01-11 | 1995-07-13 | Hine Design Incorporated | Apparatus and methods for viewing identification marks on semiconductor wafers |
| JP2000205823A (en) * | 1999-01-11 | 2000-07-28 | Tokyo Electron Ltd | Method for identifying object and method and device for positioning the same |
| US20040206819A1 (en) * | 2002-10-01 | 2004-10-21 | Aisin Engineering Co., Ltd. | Code reader |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103778421B (en) * | 2012-10-18 | 2018-01-12 | 中芯国际集成电路制造(上海)有限公司 | Read the method and Wafer identification reading device of Wafer identification |
| WO2018111227A1 (en) * | 2016-12-12 | 2018-06-21 | Intel Corporation | Systems, apparatuses, and methods for performing reticle inspections |
| CN110390325A (en) * | 2019-07-30 | 2019-10-29 | 深圳市技美智能自动化有限公司 | A kind of network centralization OCR identifying system and method |
| CN110390325B (en) * | 2019-07-30 | 2021-07-02 | 深圳市静尚云科技有限公司 | Network centralized OCR recognition system and method |
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