KR100789698B1 - Apparatus for optically recognizing wafer indentification code - Google Patents

Abstract

An apparatus for optically recognizing a wafer identification code is provided to obtain a resolution-improved image by using a diffusion plate and a reflective plate when illumination is scattered. A camera(300) captures an image of a predetermined part of a wafer. At least one lighting unit(310) provides predetermined illumination to a surface of the wafer when the camera takes pictures. At least one motor(320) is connected to the lighting unit to rotate or move the lighting unit. A motor driving unit(330) is connected to a motor to drive it. A control unit(340) controls operations of the motor driving unit, the camera, and the lighting unit. The control unit transfers a driving signal with respect to the motor to the motor driving unit to control an illumination angle of the lighting unit. A diffusion plate(360) is surface-treated, so an irradiated light is diffused. A reflective plate(350) reflects the light passing through the diffusion plate to an imaging region of the wafer.

Description

Apparatus for optically recognizing wafer indentification code

1 is a block diagram showing a general wafer prober station as a whole.

2 is a block diagram schematically showing a wafer identification code recognition device according to the prior art.

3 is a block diagram schematically illustrating an apparatus for recognizing a wafer identification code according to a preferred embodiment of the present invention.

4 is a configuration diagram schematically showing a wafer identification code recognition apparatus according to a preferred embodiment of the present invention.

5 is a view comparing images captured by controlling the lighting angle of the lighting unit according to the present invention and images captured without controlling the lighting angle of the lighting unit according to the prior art.

6 to 9 are views comparing images captured using a diffusion plate and a reflecting plate according to the present invention and images captured according to the prior art.

<Explanation of symbols for the main parts of the drawings>

30: wafer identification code recognition device

300: camera unit

310, 312: lighting unit

320, 324 motor

330: motor drive unit

340: control unit

350: reflector

360: diffuser plate

The present invention relates to a wafer identification code recognition apparatus of a wafer prober, and more particularly, to a wafer identification code recognition apparatus capable of capturing a clear image by controlling an illumination angle of an illumination unit and providing scattered illumination.

In general, a semiconductor wafer prober station is used for inspection of dies in a semiconductor wafer to electrically test whether the dies in wafer state operate normally before packaging the semiconductor chips made on the semiconductor wafer. It is one of the EDS inspection equipments in the semiconductor manufacturing process of contacting the probes, applying electrical signals to test them, and determining whether the defect is good or bad. The wafer prober described above is a process equipment for reducing raw materials, time and other losses to be used in subsequent packaging and packaging test processes by early contacting and testing the pads of the die of the wafer to eliminate defective die early.

1 is a front view of the wafer prober station as a whole. Referring to FIG. 1, the wafer prober station is a wafer loader that transfers a semiconductor wafer to a position or a chuck where it can be tested in a FOUP or a cassette, and precisely to test the wafer. A stage for transferring and contacting the probe card, and a tester for inspecting a wafer placed on a chuck on the stage. A probe card is mounted on a header of the tester, and an electrical signal is applied to a chip on a wafer using the probe card and the result is measured to check whether there is an abnormality or a defect of each chip. do.

Meanwhile, the wafer prober station needs to recognize the type of the wafer to be tested, the lot number, and the wafer identification codes. To this end, a unique identification code is assigned to each wafer, and each identification code is displayed by using an etching or printing technique at a flat surface of the wafer or at a predetermined position with respect to the flat surface. Recognizing such a wafer identification code using a camera is called optical character recognition (hereinafter referred to as 'OCR').

2 is a schematic cross-sectional view of an OCR device of a wafer prober station according to the prior art. Referring to FIG. 1, a conventional OCR device is combined with a camera module and a lighting unit. A process of identifying the wafer identification code ID using the OCR device having the above-described configuration will be briefly described. First, the wafer located in the wafer seating table is moved or rotated by controlling the motor and the motor driving unit to recognize the flat / notch of the wafer as the light sensor and the centering camera. Next, the CCD camera for identifying the wafer ID captures an area on which the wafer ID is printed, and processes and analyzes the captured image to recognize the ID of the wafer.

By the way, in recognizing the wafer identification code, the angle or amount of light on which the wafer surface reflects illumination differs depending on the surface treatment method, the wafer identification code printing method, or the like for the area where the wafer identification code is printed. As a result, in the conventional OCR apparatus provided with the same position and angle of illumination, the wafer identification code cannot be properly recognized as the type of wafer is changed.

An object of the present invention for solving the above-described problems is to provide a wafer identification code recognition apparatus that can accurately recognize the identification code by adjusting the angle and the amount of light provided to the surface of the wafer.

A feature of the present invention for achieving the above-described technical problem relates to a wafer identification code recognition device for recognizing a wafer identification code displayed on the surface of the wafer, the wafer identification code recognition device,

A camera unit for capturing an image of a predetermined position of the wafer;

At least one lighting unit for providing predetermined illumination to a surface of a wafer to be inspected when the camera unit is photographed;

At least one motor connected to each of the lighting units to rotate or move the lighting unit;

A motor driver connected to the motor to drive the motor,

And a control unit for controlling the operation of the motor driving unit, the camera unit, and the lighting unit, and the control unit transmits a driving signal for the motor to the motor driving unit to control an illumination angle of the lighting unit, thereby to capture the camera unit. The illumination can be accurately provided to the imaging area of the wafer.

According to another aspect of the present invention, a wafer identification code recognition apparatus,

A camera unit for capturing an image of a predetermined position of the wafer;

At least one lighting unit for providing predetermined illumination to a surface of a wafer to be inspected when the camera unit is photographed;

Control unit for controlling the operation of the camera unit and the lighting unit,

A diffuser plate which is surface-treated to diffuse light and is disposed in front of the lighting unit;

And a reflecting plate for reflecting the light of the lighting unit provided through the diffusion plate to the imaging area of the wafer, and the light provided from the lighting unit is scattered by the diffusion plate and the reflecting plate to provide illumination of uniform brightness to the imaging area. Be sure to

Hereinafter, a wafer identification code recognition apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. 3 is a block diagram schematically showing the configuration of the wafer identification code recognition device 30 according to the present invention, and FIG. 4 is a sectional view schematically showing only essential components of the wafer identification code recognition device 30. Hereinafter, the configuration and operation of the wafer identification code recognition device 30 according to the present invention will be described in detail with reference to FIGS. 3 and 4.

3 and 4, a wafer identification code recognition device 30 according to a preferred embodiment of the present invention is a device for recognizing a wafer identification code displayed at a predetermined position on a surface of a wafer. One or more lighting units 310 and 312, motors 320 and 324 connected to each of the lighting units, a motor driving unit 330, a controller 340 for controlling the overall operation, a reflector plate 350, and a diffusion plate 360 are provided.

The camera unit 300 captures an image of a predetermined position of the wafer and provides it to the controller 340.

The illumination units 310 and 312 are illumination lamps that provide predetermined illumination to a predetermined position on the surface of the wafer as an inspection object during imaging of the camera unit, that is, the imaging area of the wafer, and include at least one or more in the apparatus. The motors 320 and 324 are connected to each of the lighting units 310 and 312 to rotate or move the lighting unit, and are driven by the motor driving unit 330. On the other hand, the motor 320, 324 according to a preferred embodiment of the present invention may use a step motor. The motor driver 330 drives the motors 320 and 324 according to a drive signal transmitted from the controller 340. Accordingly, the lighting units 310 and 312 may be rotated or moved by a motor driven under the control of the controller 340, thereby adjusting the illumination angle.

The controller 340 controls the operation of each component module of the wafer identification code recognition device as a whole, and controls the operation of the motor driving unit, the camera unit, and the lighting unit to recognize the wafer identification code.

In particular, the control unit 340 according to the present invention transmits a drive signal for the motor to the motor driving unit to control the illumination angle of the illumination unit, the illumination can be provided accurately to the imaging area of the wafer to be captured by the camera unit Make sure

The diffusion plate 350 is surface-treated to diffuse light incident on the surface, and is disposed in front of the lighting unit. Therefore, the light provided from the lighting unit is diffused by the diffusion plate 350.

The reflective plate 360 reflects the light of the lighting unit provided through the diffusion plate 350 to the imaging area of the wafer, and the surface of the reflective plate is formed to have a curved surface having a predetermined curvature.

The light provided from the lighting unit is scattered by the diffusion plate 350 and the reflecting plate 360 to remove noise such as scratches or fingerprints that may be included in the image captured by the camera unit.

Although the present invention has been described above with reference to preferred embodiments thereof, this is merely an example and is not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. And differences relating to such modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

5 is a view comparing the captured images and the captured image without adjusting the illumination angle by adjusting the illumination angle of the illumination unit by the wafer identification code recognition device according to an embodiment of the present invention. 5 (a) is an image captured without adjusting the illumination angle of the lighting unit 312 of Figure 3, Figure 5 (b) and (c) is an image captured after adjusting the illumination angle of the lighting unit 312 admit. 5, by adjusting the illumination angle of the lighting unit according to the present invention, the captured image is more clear and as a result the identification code of the wafer can be easily recognized.

6 to 9 are views comparing images captured by using conventional basic lighting and images captured using a diffusion plate and a reflecting plate according to the present invention. 6 to 9 (a) is an image according to the prior art, (b) is an image according to the present invention. 6 to 9, it can be seen that according to the present invention the image captured in the light scattering state using the diffuser plate and the reflector plate is clearer, so that the identification code of the wafer can be more easily recognized. do.

Figure 6 (a) is an image of a state that can not recognize the identification code of the wafer due to damage such as scratches on the identification code of the wafer, Figure 6 (b) is a diffusion plate and a reflecting plate according to the present invention It is an image that captures the identification code of the wafer by penetrating the scratch.

FIG. 7 (a) is an image capturing a state in which the identification code of the wafer overlaps the pattern of the wafer so that the identification code cannot be recognized due to the wafer pattern, and FIG. 7 (b) is diffused according to the present invention. This image captures the state that only the identification code of the wafer is highlighted using the plate and the reflecting plate without being greatly influenced by the surrounding pattern.

8 (a) is an image capturing a state in which a strip engraved on the surface of the wafer is superimposed on the identification code of the wafer and because of the strip engraved on the surface, characters of the identification code of the wafer may be confused and recognized by other characters. Figure 8 (b) is an image capturing the state of killing the effect of the band engraved on the surface using a diffusion plate and a reflecting plate in accordance with the present invention to highlight only the identification code of the wafer.

9 (a) is an image capturing a state in which the identification code of the wafer cannot be easily recognized due to the fingerprint when the fingerprint of the person is buried in the identification code of the wafer, and FIG. 9 (b) shows the present invention. Accordingly, the image of the identification code of the wafer is captured by transmitting a fingerprint embedded in the identification code of the wafer using a diffusion plate and a reflection plate.

Claims (9)

In the wafer identification code recognition device for recognizing a wafer identification code displayed on the surface of the wafer, A camera unit for capturing an image of a predetermined position of the wafer; At least one lighting unit for providing predetermined illumination to a surface of a wafer to be inspected when the camera unit is photographed; At least one motor connected to each of the lighting units to rotate or move the lighting unit; A motor driver connected to the motor to drive the motor; A controller for controlling the operation of the motor driving unit, the camera unit, and the lighting unit; And the control unit transmits a driving signal for the motor to the motor driving unit to control the illumination angle of the lighting unit, so that the illumination can be accurately provided to the imaging area of the wafer to be captured by the camera unit. Wafer identification code recognition device. The wafer identification code recognition apparatus of claim 1, further comprising a diffusion plate surface-treated so that the irradiated light is diffused, and a reflection plate reflecting the light passing through the diffusion plate to the imaging area of the wafer, wherein the wafer identification code recognition device is provided from the illumination unit. Wafer identification code recognition device for scattering the light to be provided to the imaging area of the wafer. The wafer identification code recognition apparatus according to claim 2, wherein the reflecting plate has a curved surface. The wafer identification code recognition according to claim 2, wherein the diffuser plate is disposed in front of the illumination unit, and the reflector plate is disposed at a position where the light passing through the diffuser plate is reflected to the imaging area of the wafer. Device. The wafer identification code recognition apparatus according to claim 1, wherein the wafer identification code recognition apparatus arranges a diffusion plate in front of the illumination unit, and the diffusion plate is surface-treated to diffuse light provided from the illumination unit. The wafer identification code recognition apparatus according to claim 1, wherein the wafer identification code recognition apparatus further comprises a reflector for reflecting light provided from the illumination unit to an imaging area of the wafer. In the wafer identification code recognition device for recognizing a wafer identification code displayed on the surface of the wafer, A camera unit for capturing an image of a predetermined position of the wafer; At least one lighting unit for providing predetermined illumination to a surface of a wafer to be inspected when the camera unit is photographed; A control unit controlling an operation of the camera unit and the lighting unit; A diffuser plate which is surface-treated to diffuse light and is disposed in front of the lighting unit; And light provided from the illumination unit is diffused by the diffusion plate and provided to the imaging area of the wafer.  The wafer identification code recognizing apparatus of claim 7, further comprising a reflector for reflecting the light passing through the diffusion plate to the imaging area of the wafer, wherein the light is scattered from the illumination unit and provided to the imaging area of the wafer. Wafer identification code recognition device characterized in that. In the wafer identification code recognition device for recognizing a wafer identification code displayed on the surface of the wafer, A camera unit for capturing an image of a predetermined position of the wafer; At least one lighting unit for providing predetermined illumination to a surface of a wafer to be inspected when the camera unit is photographed; A control unit controlling an operation of the camera unit and the lighting unit; A reflector reflecting light provided from the illumination unit to an imaging area of the wafer; And scattering light provided from the lighting unit and providing the light to the imaging area of the wafer.

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