JPS59191679A - Reader for identification symbol or character of disk-shaped matter - Google Patents

Abstract

PURPOSE:To read the indentification characters without positioning a disk by picking up a disk having a linear notch to store it in the form of the digital information, detecting both the direction and position of said notch and reading characters based on the detected direction and position of the linear notch. CONSTITUTION:When a wafer 2 shifted by a shift device 10 passes over a photosensor 11, an image pickup device 7 stores the digital picture information of the wafer 2 to a memory part 8. The 1st processing part 13 calculates the direction and position of a notch 3 from the information. In other words, a notched fringe picture element detecting part 15 finds out a noticed fringe picture element from the picture of the wafer 2 and delivers the position of the picture element. A fringe equidistance detecting part 16 finds out two fringe picture elements set at a fixed distance from the noticed fringe picture element and delivers the positions of these picture elements. A straight line discriminating part 17 delivers ''genuine'' when three fringe picture elements are put on a straight line. The direction and position of the notch 3 are calculated by a notch direction calculating part 19. Then the 2nd processing part 14 segments the part of a character 1 for indentification on the basis of those above-mentioned information. Thus a character having no inclination is read.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a semiconductor substrate (
Regarding devices for reading identification symbols and characters written on disc-shaped bodies with linear notches, such as wafers (hereinafter referred to as wafers), mechanical positioning of disc-shaped bodies (hereinafter referred to as wafers) As shown in Figure 1, the surface of the wafer 2 is marked with identification symbols or letters such as the lot name or number to indicate the type of wafer and processing history. is written with reference to a notch 3 called an orientation flat provided in the wafer 2. A conventional example of a device for reading this type of identification symbol or letter l - shown in Fig. 2 @Conventional example of Fig. 2 equipment M#i, centering jig 4, (b) rotatable wafer holder 5 and photosensor 6, such wafer positioning means, an identification symbol or letter lt-, an imaging device 7 for imaging, and an imaging signal The device is comprised of a storage unit 8 that stores the image as digital image information, and a reading processing unit 9 that reads the identification symbol or letter l from the digital image information.The operation of this conventional device is as follows: Transfer device l
The wafer 2 sent by O is centered using the centering jig 4, and in this state, the wafer holder 5 holds the wafer 2, then rotates it once, and the orientation flat is set by the word of the photosensor 6. (notch)
After performing this mechanical positioning operation, that is, after setting the identification symbol or letter l in a fixed direction and position, the imaging device 7 aligns the identification symbol cylinder or The character l is imaged, and the identification symbol or the character l is read from the digital image information written in the storage unit 8 by the trap and is read by the processing unit 9. There are many contact parts with the wafer 2, and there is a problem that mechanical force is applied to center and hold the wafer 2, which may cause contamination or damage to the wafer 2. Because processing time is required for positioning, high-speed reading nK for moving wafers is essentially not suitable.The present invention eliminates the problems of the prior art described above by using mechanical positioning. i1 The purpose is to provide a device that can read and accept identification symbols or characters written on the basis of the notch without performing a determination operation. is imaged without positioning, and from the digital image information obtained from this K, the direction and position of the notch, which is the reference for the identification symbol or character, f, :17#
This can be achieved by reading the identification symbol or character based on the information on the direction and position of the notch.Hereinafter, the present invention will be explained with reference to FIGS. 3 and 4. FIG. 3 shows an embodiment of the present invention in which an identification symbol or letter l is written with reference to a linear notch (orientation flat) 3 of the wafer 2. In FIG. 3, the transfer device 10tj may be of any type, such as a commonly used belt-driven device or an air-driven device suitable for high-speed transfer. Reference numeral 11 denotes a photosensor for detecting the presence or absence of the wafer 2, and in this example, it is embedded in the transfer device IO. The imaging device 7 is configured to image the entire wafer 2, and when the presence of the wafer 2 is detected by the photosensor 114C, image information of the wafer 2 is instantly stored.
Reference numeral 12 denotes a light source 69 installed in an annular shape (around the optical axis of the imaging device 7), which is installed in order to obtain a constant scattered light regardless of the position or inclination of the identification symbol or letter l. It is. Therefore, the light source 12 itself does not have to be an annular body.◎The imaging signal output from the imaging device 7 is A/converted and then taken into the storage unit 8 as digital image information @13 is a notch (orientation flat) 3
This is the first processing unit that performs detection, and calculates information on the direction and position of the notch 3 based on the stored digital image information. 14tit This is a second processing unit that reads the identification symbol or letter l, and reads the identification symbol or letter based on the previously determined direction and position information of the notch 3 and the already stored digital image information. The details of the first and second processing units 13 and 14 will be explained later.

The operation of the reading device of the present invention will be explained. Transfer device 10
When the wafer 2, which has moved from 4c, passes completely over the photo sensor 11, regardless of the orientation of the wafer 2, a change in the output of the sensor 11 triggers the imaging signal from the imaging device 7 to be instantly stored in the storage unit as digital image information. 8 is stored.

Information on the direction and position of the notch 3 of Ueno 2 is calculated in the first processing unit 13 based on the stored digital image information, and then in the second processing unit 14, information on the direction and position of the notch 3 is calculated. Identification signal or letter l part is cut 9
without reversing the order of symbols or letters.
Reading J12 is performed.

Next, a specific example of the first processing unit 13 regarding detection of the notch 3 will be described. The first processing unit 13 in this example includes a peripheral pixel of interest detection unit 15, a peripheral edge equidistance detection unit 16, and a straight line determination unit 17.
, a pixel of interest movement processing section 18 , and a notch direction calculation section 19 . The first detection unit 15 is a processing means for finding an arbitrary peripheral pixel Po of interest from the image of the wafer 2 and outputting its position information.

Specifically, full, for example, pixel S at the center of the left edge of the screen! The zero-order detection unit 16 sequentially scans from the center pixel Sz at the right end while detecting 0N10FF of each pixel, and first obtains the pixel that becomes 0N4C from KOFF as Po. Certain two peripheral pixels PK-
Pxt - A processing means for outputting headings and respective position information. Specifically, for example, we create a circular pattern consisting of a group of pixels that are a certain distance rVc from the central pixel, and then create a circular pattern that is the same as the isomorphic pattern when the central pixel of this circular pattern is matched with the previously determined PoK. Find P, , P as the intersection with the wafer periphery ◎ Straight line judgment unit 17
is a means of determining whether or not the three peripheral pixels POmP□aP2 are on the @ line based on the position information of the three peripheral pixels POmP□aP2 obtained as described above; if they are on the straight line, the information is "true"! otherwise outputs I/'i "false" information. “True” information was output *@d, a. 0. . , 9e 2, 3.
. □ Information on the direction and position of the notch 3 is extracted based on the position information of the pixels Po, P, , P, and this is output to the second processing section 14. If "false" information is output, the target pixel movement processing unit 19 is operated.This causes the target peripheral pixel P to be moved to either of the two peripheral pixels P1 or P2 found by the second detection unit 16.・Move S, and then detect ff1ll 6. The notch 3, which is a straight line portion, can be detected while the straight line P makes a turn.

On the other hand, a specific example of the second processing unit 14 regarding reading will be explained. The second processing section 14 in this example includes an identification symbol or character cutout processing section 2° and a reading processing section 21. The cutout processing unit 20 extracts only the image information of the identification symbol or the letter l from the digital image information stored in the storage unit 8 based on the information on the direction and position of the notch 3 output from the notch direction calculation unit 19. Take out. For example, if this image information is the letter "A", it will generally have a tilted image as shown in FIG. Get an image of it as a symbol or character. Therefore, the reading processing section 21 may be any ordinary symbol or character reading means, and by operating this, the identification of the wafer 2 is completed.

As explained above, the present invention images a disk-shaped object such as a wafer sent by a transfer device, and uses the image signal to obtain information on the direction and position of a notch (orientation flat) that serves as a reference for an identification symbol or character. Since this is a device that reads identification symbols or characters based on this information, there is no need for mechanical positioning of the disc-shaped body, and therefore there is no possibility of damage or contamination of the disc-shaped body. In addition, since it can be read at high speed, it is possible to identify disc-shaped objects even when they are moving.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a semiconductor substrate (wafer) shown as an example of a disk-shaped body with identification symbols or characters written on it; FIG. 2 is a configuration diagram of a conventional reading device; FIG. 3 is an embodiment of the present invention. The configuration diagram of the example device, FIG. 4(a), Φ) is an explanatory diagram illustrating the process of cutting out identification symbols or characters. In the drawing, lFi identification symbol or letter, 2#i disc-shaped body (Ueno S), 3#i notch (orientation flat), 7#'i
8 is a storage unit for digital image information; 10 is a transfer device; 11 is a means for detecting the presence or absence of a disc-shaped body (photo sensor); 12 is a light source; 13 is a notch detection processing unit; 14 #'i identification It is a processing unit for reading and processing symbols or characters.@Patent applicant: Nippon Telegraph and Telephone Public Corporation Representative: Patent attorney: Mr. Mitsuishi (and 1 other person) JP-A-59-191679 (5)

Claims (1)

[Claims] [The identification symbol or 7C written on the disc-shaped body having an N-shaped notch with foreign exchange -sK with this notch as a reference is placed in a text reading device to detect the presence or absence of the disc-shaped body. a detection means, an imitation imaging means for imaging the disc-shaped body using the detection force, an illumination means installed in an inner annular shape around the optical axis of the imaging means, and storing the imaging signal as digital image information. consideration means; notch detection processing means for detecting the entire direction and position of the notch from stored digital image information; reading processing means for reading the symbol or character T;
1. A device for reading identification symbols or characters on the same plate-shaped object.