JPS6136704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic chip sorting device that detects a judgment mark on a chip and automatically removes chips with the mark during the manufacturing process of semiconductor chips and the like.

The sorting process in conventional semiconductor chip manufacturing is
With each chip unseparated, the wafer is first electrically inspected using a wafer rover, and for defective chips, a V-shaped defective mark or laser irradiation mark is placed near the center of the chip, and then the wafer is placed on a transparent sheet. A scriber is used to create cracks on all four sides of each chip, a sheet is placed over the cracked wafer, and the sandwiched wafer is pressed down with a pressure roller to separate each chip into individual chips. Next, the sheet placed over the wafer is removed, placed on a ring-shaped jig, and the sheet protruding from the ring-shaped jig is held and enlarged.
As a result, the chips are arranged in a matrix on the sheet at intervals from each other. In this state, chips with defective marks were conventionally removed from the sheet by visual inspection, but the work was inefficient as it relied on manual labor, and since the task was simple, it was difficult to automate this visual inspection. It was strongly desired.

SUMMARY OF THE INVENTION Thus, an object of the present invention is to provide an automatic chip sorting device that quickly finds and removes chips with marks, for example, defective marks, from a group of chips stretched on a ring-shaped jig.

In order to achieve this object, the automatic chip sorting device according to the present invention has an illumination system that epi-illuminates one chip from directly above, and an optical system that magnifies the chip at an appropriate magnification, and converts the optical image into a video signal. When inputting an optical image to the camera, the chip on the sheet is pushed up from below with a shaft with a flat tip, positioning the chip directly below the camera at right angles to the optical system, and tilting the surrounding chips. When detecting the chip position, the camera outputs a video signal for a range that includes at least the entire area of one chip, taking into account position errors, and for a range slightly inside the outer circumference of one chip when detecting a mark. A scan area setting circuit, a binarization circuit that binarizes the video signal into "1" or "0" with an appropriate threshold value, and a reference information setting circuit that stores information such as the size of the target chip and the reference position. The information stored therein, such as the size and position of the chip, is compared with the chip signal after binarization, and the information in the X direction and Y direction is compared.
A position detection circuit that calculates the amount of deviation in direction and rotation, a chip positioning circuit that drives an a mark detection circuit that detects the presence or absence of a mark marked on a chip from a binary signal in the inner region; and a switching circuit that sends the binary signal to the position detection circuit when detecting the chip position and to the mark detection circuit when detecting a mark. , a mechanism control unit that controls the chip pushing up mechanism and a chip removal mechanism that removes the chip when a mark is detected, and a control unit that sequence controls all of the above.

According to the configuration of the present invention, it is possible to automatically position a large number of chips placed on a ring-shaped jig and to automatically remove chips with marks therefrom.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings regarding the automatic selection of defective semiconductor chips. FIG. 1 is a block diagram showing the configuration of an apparatus according to the present invention. FIG. 2 is a diagram for explaining the illumination system for illuminating the chip in FIG. 1, and FIG. 3 is a diagram showing step-by-step images captured by the camera.
In FIG. 1, when a ring-shaped jig 2 in which a large number of semiconductor chips 3 are arranged in a matrix is placed on an The first chip is roughly positioned in the center below the camera. Next, as shown in FIG. 2, the tip 3 is pushed up from under the sheet with a shaft end 104 that has a flat tip and has approximately the same area as the outside diameter of the tip 3.
The pushed up chip 3 is oriented perpendicular to the optical axis of the camera and illumination system, and the chip 3' surrounding the chip 3 and the sheet 1 near the chip 3
is given a slope. Therefore, the illumination light that hits the surface of the chip 3 is directly reflected and is introduced into the camera as an optical image of the chip via the lens 23 and the half mirror 22. The illumination light reflected from the chip 3' close to the chip 3' is reflected at a certain angle to the optical axis of the camera, and is not guided to the camera as a clear optical image. That is, the image of only the chip 3 to be inspected is clearly projected, the images of other chips and sheets around it become unclear, and the image of the target chip 3 stands out from the others. This optical image of the chip 3 is introduced to the photoelectric conversion surface of the camera 50.
At this time, the scan area setting circuit 40 is configured so that the camera 50 photoelectrically converts only the signals of an area sufficient to include at least the chip to be inspected, and other signals are ignored. Furthermore, the scan area for photoelectric conversion is set on four sides that completely contain at least one chip, including positional variations due to uneven chip alignment and positioning errors of the ring jig, as shown in 1 in Figure 3. Let the shape be 41, and this quadrilateral 41
The range is set so that the entire surfaces of two chips are not included at the same time. Returning to FIG. 1, the video signal from the camera 50 is immediately sent to the binarization circuit 60 and binarized into "1" or "0" using an appropriate threshold. This digitally converted signal is sequentially sent to the position detection circuit 80 by connecting the switching circuit 70 to the position detection circuit 80. The position detection circuit 80 removes signals from other chips, nozzles, etc. depending on whether the straight line formed by the locus of points where the signal changes from "0" to "1" forms a quadrilateral. The obtained quadrilateral is used as a reference information setting circuit 81.
The positional deviations ΔX, ΔY, and ΔΘ of the chip from the reference position are calculated by comparing and calculating the size of the chip and standard data of the reference position stored in advance. Immediately after the detection of the position of the chip 3 is completed, the chip lifting mechanism 101 descends, and the calculated positional deviation is sent from the control section 30 to the chip positioning circuit 10, which drives the XYΘ table 11. The chip position is corrected as shown. Subsequently, in order to detect whether or not a defective mark 4 is attached to this chip 3, the scan area setting circuit 40 sets the camera to a quadrilateral area 42 that is slightly smaller than the outer periphery of the chip 3, as shown in 3 in FIG. 50 is outputted, and the binary signals are sequentially input to the mark detection circuit 90 in the same way as described above. As soon as the mark detection circuit 90 detects the presence or absence of diagonal lines, which is a characteristic of the defective mark 4, it is determined whether the chip 3 is defective or not. This judgment result is sent to the control unit 30, and if the chip is defective, the mechanism control unit 100 operates the chip pushing up mechanism 101 to push the chip 3 up a little from the sheet 1 so that the chip 3 can be easily removed from above. A chip removal mechanism 102 equipped with a suction nozzle 103 at the tip operates to remove defective chips from the sheet 1.
remove from If it is not a defective chip, the XYΘ table 11 moves to the next chip and repeats the above operation for all the chips placed on the ring-shaped jig 2, thereby removing all the defective chips.

Since the present invention is configured as described above, one of its effects is that it becomes possible to automatically remove defective chips from all the chips mounted on the ring jig, which is a work that previously had to be done manually. can be unmanned. Next, during chip position detection, the chip to be inspected is slightly lifted from the bottom of the sheet, so almost no images other than the chip to be detected are input to the camera, resulting in a high-contrast image that can be used for subsequent binarization or position detection circuits. Easy to configure. Furthermore, since the video output area from the camera is reduced to the minimum necessary size, there are excellent advantages such as short signal processing time.

As explained above, the present invention enables the automatic selection of chips, which has hindered automation in the semiconductor assembly process, and its effects are extremely large.

Although the present invention has been described by removing defective chips, it goes without saying that the present invention also includes a configuration in which good chips are replaced with another sheet. Furthermore, although the above description has been mainly applied to an automatic sorting apparatus for determining whether semiconductor chips are good or bad, it goes without saying that the present invention can also be used for other automatic sorting apparatuses.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to the present invention, and FIG. 2 is a partially enlarged view of the illumination system in FIG.
Figure 3 is a diagram showing the image captured by the camera, 1
2 indicates a state in which the chip to be inspected is misaligned, 2 indicates a state in which the misalignment has been corrected, and 3 indicates a state in which a mark is being detected. 1... Sheet, 2... Ring-shaped jig, 3... Chip, 10... Chip positioning circuit, 11...
XYΘ table, 21... lighting lamp, 23...
Lens, 30...Control unit, 40...Scan area setting circuit, 50...Camera, 60...Binarization circuit, 70...Switching circuit, 80...Position detection circuit,
81... Reference information setting circuit, 90... Mark detection circuit, 100... Mechanism control section, 101... Pushing up mechanism, 102... Chip removal mechanism.

Claims (1)

[Claims] 1. An illumination system that epi-illuminates the chip from directly above, a camera that has an optical system that magnifies the chip at an appropriate magnification and photoelectrically converts the optical image into a video signal, and a chip pushing mechanism that pushes up the chip from below with a shaft with a flat tip, positions the chip directly below the camera at right angles to the optical system, and tilts the surrounding chips;
a scan area setting circuit configured to output a video signal from a camera to a range including the entire area of at least one chip when detecting a chip position, and to an area slightly inside the outer periphery of one chip when detecting a mark; A binarization circuit that binarizes a signal into "1" or "0" with an appropriate threshold value, a reference information setting circuit that stores information such as the size of the target chip and the reference position, and the information stored therein. A position detection circuit that compares the reference information with the chip signal after binarization and calculates the amount of deviation in the X direction, Y direction, and rotation, and drives the XYΘ table according to the calculated amount of deviation to place the chip in the reference position. a mark detection circuit that detects the presence or absence of a mark on the chip from a binary signal in an area slightly inside the outer periphery of the chip; and a position detection circuit that detects the chip position using the binary signal. and a mechanism control unit that controls a switching circuit that sends the signal to the mark detection circuit when a mark is detected, the chip pushing mechanism, and a chip removal mechanism that removes the chip when a mark is detected, and a control unit that sequence-controls all of the above. An automatic chip sorting device characterized by the following configuration.