JPH02135752A - Wafer detector - Google Patents

Abstract

PURPOSE:To easily detect the presence or absence of a wafer by imaging the light reflected on the edge of the wafer from the light of a light source by a television camera, and image-processing it. CONSTITUTION:A television camera 1 is employed as a photodetector, and a light source 3, the photodetector 1 are disposed in front of a wafer cassette 24 out of a processing chamber 26. Since a wafer edge ls formed with a smoothly curved face from the lower face to the upper face of the wafer, a light from the light source is reflected at any point of the edge of the wafer toward the camera. This light is obtained as a point of high intensity on the camera 1, and collected as an image dotted with the lights reflected on the edge of the whole wafer They are image-processed to obtain the positions of the points having high intensity, and all the obtained positions are made to correspond to the slots of a wafer cassette 4. Thus, the presence or absence state of the wafer of all the slots can be easily detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [1!1 Field of Industrial Application] The present invention relates to a wafer detection device that extracts a wafer stored in a wafer cassette.

When unfeeding, detect the wafer trying to eject uL [
PRIOR ART AND PROBLEMS] In the semicircular assembly, the wafer is stored in a wafer cassette during the circuit manufacturing process, and the wafer is waved between each process. In the process, wafers are taken out one by one from the wafer cassette, each a-processed, and 16FJ wafers are processed at 1mBS.
The wafer is housed in a JTL wafer cassette. In this way, the special M 18283-1883 was used to detect the presence or absence of a wafer when removing a wafer from a wafer cassette.
As shown in step 4, the light rl and the light detection port were placed directly opposite each other, and the wafer cassette was placed on the nnm, and the n sieve was moved up and down every time one wafer was detected, so that the wafer blocked the light from the light source. The presence or absence of a wafer was detected by optical detection.

If wafer processing is carried out in a vacuum chamber or in a gas machine, using the civil engineering method, it may be difficult to obtain a light source or light detector that can withstand Q-shaped mounds such as y4 air, gas, etc., or R brocades are required. There were problems such as an increase in 1τ.

[Means for solving the 11 points in between] Use a television camera as a light detection port and a light source.

A photodetector is placed outside the M PI M (directly facing the wafer cassette. Since the wafer edge portion is formed of l1kIiI which is smooth from the bottom surface to the top surface of the wafer,
Light from the light source is reflected toward the television camera at any point on the edge of the wafer. This light is l for a TV camera.
The light is obtained as li with a high degree of i, and the light reflected at the edge of the entire wafer is captured as scattered IeiA.

By calculating the position of the point where the brightness is γ≦ by performing both 6 processes and associating the obtained position with the slot of the wafer cassette, the :ff thermal state of the wafer in all slots can be detected. can do.

[Effect] According to the above method, 16F! ! It is not affected by the food paste pile, and also eliminates the need for the 8-motion mechanism of the wafer cassette. It becomes possible to configure a wafer detection device - [! J! , Example] An example of the present invention will be described in detail below with reference to nine drawings.

Figure 1 is book 5! This shows an example of a bright configuration, where 1 is a camera, 2
3 is N-made 16FJ *Otsu, 4 is a wafer cassette, and 5 is a wafer.

Figure 2 is a camera, light! , Wafer Cassette Isl!
t, and the camera 21 is moved so that the JA axis of the camera 21 is in the middle of the lf width direction of the wafer cassette 24 and almost parallel to the wafer 25. Do t. The light source 2 is placed on or above the camera Ic so that its irradiation direction intersects the camera optical axis at a shallow angle.

Figure 3 is a surface image of the wafer being placed in the arrangement shown in Figure 2! The bright areas reflected by the wafer knee edges are indicated by black circles.

24 is rM3's i! It is a binary bisexuality that is a binary representation of i-Buddha.

Place the wafers in all slots of the wafer cassette correctly, and place the wafer cassette in the correct position. In this state i! When the j image is manually created, y! Milo of 3 is 17 times nine. If WiO is binarized so that the bright part of 100 is white and the part that is 1w1 is black.

Only the part indicated by the black nine in Figure 3 has become white 241! Wa
is bitten (Fig. 4), find the center of gravity of each white part of the 2kliN image, and find its yl! 153 corresponds to slot number 1, and each slot's! Stored in memory as f quasi y released prisoner.

In the wafer presence/absence detection, a table for storing the wafer presence/absence of all slots is used on the memory of the decoy image processing device, and the table is set to a wafer heating state before detection. An image of the wafer cassette is input, binarized using the method described above, and the center of gravity of each white portion of Ia is determined. Find the center of gravity y! ! The i standard value and the standard yflt standard of each slot are successively compared.5 If the difference is less than a certain value (usually 1/2 or less of the slot barrier), The table is set in a wafer-like state. In this way, all the calculated centers of gravity y1! Comparison of mark i with base mark y, line 6s
, records the comparison results in a table. When all comparisons are completed, the current state of the wafers in the wafer cassette is created in a table in memory.

[Effects of the Invention] The wafer detection device of the present invention achieves +2
This method has the advantage that the presence or absence of a wafer can be detected without depending on the environment and without increasing the volume of treated water.

[Brief explanation of the drawing]

The first ffd is an η diagram of an embodiment of the present invention, and the second figure is a diagram. 1.Fll nail installation.・Camera, 2...1 Light Whale, 3...Hei + place 4...Wafer cassette, 5...Work 21...Camera, 22
・Fist・Light Z2.24・Wafer f) Set, 25・
...Wafer, 28. Processing chamber.

Claims (1)

[Scope of Claims] A wafer transfer device that extracts and transfers a plurality of wafers stored in a cassette from the cassette,
It has means for detecting the presence or absence of a wafer in each slot in the cassette, and the detecting means images the light emitted from the light source reflected by the edge of the wafer with a television camera and processes the image. A wafer detection device characterized by detecting the presence or absence of a wafer.