JPS6312903A - Detector for tip position of lead - Google Patents

Abstract

PURPOSE:To obtain a device which does not require man-hours for adjustment by reducing the opening area of an optical fiber and increasing the number of optical fibers. CONSTITUTION:A sensor is a reflection type photosensor which has a projection part 4 and a photodetection part 5 and N couples of optical fibers 4a and 5a for projection and photodetection whose tip are united are arranged linearly at equal intervals to constituted an optical fiber array 3. Then, the array 3 is arranged at right angles to the external lead array of a semiconductor device 1 and also installed above the tip part of the external lead 1a. Then when the device 1 is moved, which optical fiber in the array 3 the lead 1a passes below is detected. Then, an optical fiber which performs photodetection sends its photodetection output signal to a storage part 7. This is performed by each lead 1a and an arithmetic part 8 computes the center position of each lead 1a. Thus, even if the lead 1a shifts in position to right or left, the position is known and corrcted only by signal processing, thereby reducing the man-hour for adjustment greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to appearance inspection of semiconductor devices, and particularly to an apparatus for detecting the tip position of an external lead.

[Conventional technology]

Conventionally, a sensor part in a device for detecting the tip position of an external lead of a semiconductor device is as follows. That is,
As shown in FIG. 5, an optical fiber 2 having a predetermined width and having a light emitting part and a light receiving part integrated is placed above the tip of the external lead 1a as a sensor, and the semiconductor device 1 is connected to the optical fiber 2. For example, when a DIP type semiconductor device fi is turned over and its back side is moved on a rail (in a direction perpendicular to the drawing), if the optical fiber receives the reflected light from the tip of the external lead la, it is a good product. If the product does not pass, it will be determined to be defective. In FIG. 5, the external lead lal is a good product, and the external leads lag and lag are defective.

[Problem that the invention seeks to solve]

The aperture area of the optical fiber 2 of the sensor mentioned above cannot be made very wide due to the accuracy of position detection at the tip, so the setting position must be changed each time the standard of the bending angle of the external lead is changed. In some cases, a new sensor must be prepared for this purpose.

Furthermore, if the moving conditions of the semiconductor device are changed, the position of the optical fiber 2 that is considered to be a good product may change relative to the left or right.
Crab shifts. In that case, it is necessary to adjust the set position ti of the optical fiber 2 each time, which requires a lot of man-hours.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved lead tip position detection device that does not require unnecessary adjustment man-hours.

[Means for solving problems]

The lead tip position detection device of the present invention has a pair of light emitting and
A reflective photosensor group in which the tip of a light-receiving optical fiber is integrated, a position detection sensor forming an optical fiber array in which the integrated part is arranged in a straight line at equal intervals, and the optical fiber array, a storage unit that stores data from each photosensor when the external lead tips of the semiconductor device are brought into close proximity and relatively moved in the lateral direction;

The device also includes a calculation unit that calculates the external lead tip position from the data in the storage unit.

[Effect]

The aperture area of the optical fibers (integrated part of the light emitting and light receiving optical fibers) that make up the optical fiber array is made small, but by increasing the number of optical fibers, even if the lead tip position shifts, the optical fiber play can be maintained. Where below the optical fiber? It is possible to detect whether it has passed. Furthermore, since the opening area of the optical fiber is small, the resolution of position detection is high and the position of the external lead can be detected accurately, as will be explained in the examples.

Therefore, even if the measurement conditions change, such as a change in the bending angle standard, this can be handled without changing the set position t of the optical fiber array of the detection device.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a functional block diagram of a lead tip position detection device according to the present invention. In FIG. 1, the senna is a reflective photosensor having a light emitting part t and a light receiving part 5, and as shown in FIG.
N optical fibers, each of which is integrated at the tip a, are arranged in a straight line at equal intervals to form an optical fiber array 3t. 6
Y′i is a power source for the light projecting unit 4; 7 is a storage unit that receives the signal from the sensor and stores its contents; 8 is a unit that calculates the signal stored in the storage unit 7 to determine the position of the external lead 1a; This is an arithmetic unit that performs calculations.

The relative positional relationship between the sensor and the semiconductor device 1 is as follows. That is, as shown in FIG. 1, the optical fiber array 3t is disposed perpendicular to the external lead row of the semiconductor device 1, and is disposed above the tips of the external leads 1a. When the semiconductor device 1 is moved in the direction of the arrow in FIG. 3, it is detected which position of the optical fiber in the optical fiber array 3 the external lead 1a of the semiconductor device passes under. For example, the second to m-th optical fibers counting from the left of the optical fiber array 3 receive light and send the received light output signals to the storage section 7 . This is done for each external lead 1a. The calculation unit 8 calculates the center position of each external lead.

In the above example, the light is received from the ward to the mth -Q Therefore, (Q + -7-) is the center position.

There are cases where m-Q is an odd number and a case where it is an even number, but in the case of an odd number, for example, m=10. When rfl=13, from FIG. 4, the center position is CE between 11 and 12. Also,
In the case of an even number, for example, N=lO, in the case of m=14, 1
If the center C8 of 2 is the center position, the resolution will be half the size (diameter) of the optical fiber. Therefore, the outer shape of the optical fiber is selected depending on the accuracy of the bending standard of the external lead. Then, the bend 'i is calculated by comparing it with a value set in advance as a normal position. Signal processing such as comparison in the control section for calculating the amount of curvature of the external lead and determination of quality is the same as in the known conventional method, and therefore will not be described here.

[Effect of the invention] Even if the moving conditions of the semiconductor device change or the position of the external lead shifts relatively to the left or right, the position of the external lead can be known and correction can be made only by signal processing. There is no need to adjust to the setting position 1 of 2, and the number of man-hours for adjustment is significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram of the lead tip position detection device according to the present invention, Fig. 2 is an explanatory diagram of the optical fiber section, and Figs. 3 and 4 show the relative positional relationship between the optical fiber array and the external lead. FIG. 5 is an explanatory diagram of a sensor portion in a conventional external lead tip position detection device. 1...Semiconductor device, la...External lead,
2... Optical fiber, 3... Optical fiber array, 4... Light emitter, 5... Light receiver, 6...
- Power source for the light projecting section, 7...Storage section, 8...Calculation section.

Claims (1)

[Scope of Claims] Consisting of a group of reflective photosensors in which the ends of paired light emitting and light receiving optical fibers are integrated, the integrated parts are arranged in a straight line at equal intervals to form an optical fiber array. a storage unit that stores data from each photosensor when an external lead end portion of a semiconductor device is moved in a lateral direction relative to the detection sensor and the optical fiber array;
What is claimed is: 1. A lead tip position detection device for a semiconductor device, comprising: an arithmetic unit that calculates an external lead tip position from data in the storage unit.