JPH0810711B2 - How to recognize small work pieces - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recognizing a minute work piece, and more specifically, a method for pattern recognition of a large number of semiconductor pellets obtained by dividing a semiconductor wafer in a pellet mounting process or the like in manufacturing a semiconductor device. It is about.

2. Description of the Related Art For example, in a pellet mounting process in manufacturing a semiconductor device, a large number of semiconductor pellets obtained by dividing a semiconductor wafer (hereinafter simply referred to as pellets) are sequentially picked up and transferred to a predetermined position to mount a pellet on a lead frame. Position and place on.

In the above-mentioned pellet pick-up operation, the semiconductor wafer is divided into lattices for each pellet unit, and these divided semiconductor pellets are moved at a fixed pitch in the X and Y directions on the XY table to place the desired pellets at the pickup position. Then, the pellets are position-corrected in the XY and θ directions and then picked up.

At the time of this pickup, in order to correct the position of the pellet, it is necessary to image-process the pellet and recognize the pattern. The second conventional example of the above pellet recognition method will be described below.
Description will be made with reference to FIGS. A large number of pellets (1) obtained by dividing a semiconductor wafer as shown in FIG.
(1) ... are arranged on the XY table (2), and the image is processed by the TV camera (3). Conventionally, one pellet (1) is enlarged and imaged by the TV camera (3), and the video signal thereof is converted into a digital signal by a binarization circuit (4). The data obtained by this digital signal is stored in the frame memory (5), and the frame memory (5) is stored.
Image processing is performed by the CPU [central processing unit] (6) based on the data of (1). As a result, the CPU (6) sends an output signal to the XY table drive circuit (7) to drive the XY table (2), and the image is taken by the TV camera (3).
Correct the position of one pellet (1).

When the position correction of the pellet (1) is completed, the output signal of the pickup drive circuit (8) is sent from the CPU (6) to drive the mounter (9) [see FIG. 2] as shown in FIG. To start the pickup operation. When the pick-up operation of the pellet (1) by the mounter (9) is completed, the XY table (2) is driven based on the output signal from the mounter (9) to move the XY table (2) at a constant pitch, and the next pellet to be recognized ( 1) for TV camera (3)
Set within the field of view of the camera and capture an image. Then, by repeating the above operation, the pellet (1) on the XY table (2)
(1) are sequentially recognized and picked up.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional pellet recognition method, one pellet (1) is set within the field of view of the camera to perform image processing,
After the position of the pellet (1) is corrected based on this image processing, the pellet (1) is picked up by the mounter (9). During this pickup, the mounter (9) blocks the view of the camera and the XY table (2) cannot be driven, so that the next pellet recognition operation is stopped. Therefore, after the pickup of the pellet (1) is completed, the XY table (2) is moved at a constant pitch to set the next one pellet (1) to be recognized within the camera visual field. ) Was corrected and picked up. As described above, in the conventional method, it is difficult to recognize the next pellet (1) until the pickup of the pellet (1) is completed, which makes it difficult to speed up the index.

Means for Solving the Problems The present invention has been proposed in view of the above problems, and a technical means for solving the problems is to provide a large number of aligned minute workpieces within the field of view of a camera. The method of pattern recognition by the image processing of and picking up sequentially,
A method of recognizing a minute work piece by setting a plurality of minute work pieces in the camera field of view and performing image processing, and recognizing a pattern of the next minute work piece based on image data from the camera field of view while picking up one minute work piece. Is.

According to the method of the present invention, during the pick-up operation of one minute work piece, the pattern recognition of the next minute work piece to be recognized is performed based on the image data from the field of view of the camera. After that, the position of the next small work piece is directly corrected and placed at the pickup position without moving it at a constant pitch, and the time loss due to the drive until the position correction of the minute work piece is completed can be set to the minimum. .

EXAMPLE An example in which the method of the present invention is applied in a pellet mounting process for manufacturing a semiconductor device will be described with reference to FIG.
FIG. 1 is a flowchart showing pellet recognition and control sequence in the method of the present invention. The block diagram of the constituent circuits in the method of the present invention is the same as that shown in FIG. 2 according to the conventional method, which will be described with reference to FIG.

First, as shown in FIG. 2, pellets (1) (1) ...
It is placed on the table (2) and the image is processed by the TV camera (3). In the method of the present invention, the TV camera (3)
Is set to a desired magnification and a plurality of [for example, three] pellets (1) (1) (1) are magnified and imaged by the camera (3), and the video signal thereof is binarized (4). Convert to digital signal with. The data obtained by this digital signal is stored in the frame memory (5), and the CPU (6) performs image processing based on the data in the frame memory (5). As a result, the XY table (2) is driven by the output signal from the CPU (6), and the first pellet (1) among the pellets (1) (1) (1) imaged by the TV camera (3) is ) Position is corrected.

When the position correction of the first pellet (1) is completed, an output signal is sent from the CPU (6) to the pickup drive circuit (8) to drive the mounter (9) as shown in FIG. Start operation. During the pickup operation of the first pellet (1), the second pellet adjacent to the first pellet (1) is set based on the data set in the field of view of the camera and stored in the frame memory (5).
The pattern of the second pellet (1) is recognized, and whether the second pellet (1) is good or defective is determined.

If the second pellet (1) is a non-defective product, when the pickup operation of the first pellet (1) is completed, a pickup completion signal is received from the mounter (9) and the XY table (2) is displayed. The second pellet (1) is placed at the pickup position by driving and directly correcting the position. Also, the second pellet (1)
Is a defective product, the second pellet (1) and the adjacent third pellet (1) are driven all at once to recognize the pattern and determine whether the third pellet (1) is good or defective. However, if the third pellet (1) is a non-defective product, when the pickup operation of the first pellet (1) is completed, the pickup completion signal from the mounter (9) is received to drive the XY table (2). Then, the second pellet (1) is ignored and the third pellet (1) is reached, and after pattern recognition, the position is corrected, and the second pellet (1) is placed at the pickup position. Further, if the third pellet (1) is defective, the initial state is restored and the next plurality of pellets (1) (1) ... Are set within the camera visual field. By repeating the above operation, the pellets (1), (1), ... Are picked up sequentially on the XY table (1) while recognizing the pattern of the next pellet (1) during the pickup operation of the pellet (1).

Incidentally, in the above-mentioned embodiment, the case where the invention is applied to the pellet recognition in the pellet mounting step in the semiconductor device manufacturing has been described, but the present invention is not limited to this, and a large number of minute work pieces other than the above-mentioned pellets are arranged. Of course, it can be applied to pattern recognition in some cases.

EFFECTS OF THE INVENTION According to the method of the present invention, the pattern of the next minute work piece is recognized during the pick-up operation of the minute work piece, so that the next minute work piece is moved at a constant pitch after the completion of the pick-up operation as in the prior art. No need. Therefore, the time loss due to the movement of the minute work piece can be minimized, and the speeding up of the index can be easily realized.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining an embodiment of a method for recognizing a minute work piece according to the present invention. FIG. 2 is a block diagram of a configuration circuit for explaining pellet recognition in a pellet mounting step in manufacturing a semiconductor device, and FIG. 3 is a flowchart for explaining a conventional example of a pellet recognition method. (1) …… Small work piece [pellet], (3) …… TV camera, (9) …… Mounter [pickup].

Claims (1)

[Claims] 1. A method for recognizing a pattern of a large number of aligned minute work pieces by image processing within a camera field of view and picking them up sequentially, wherein a plurality of minute work pieces are set within the camera field of view for image processing. Then, during the pick-up operation of one micro work piece, a pattern recognition of the next micro work piece is performed based on the image data from the camera field of view.