JPH035660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a lead frame feeding mechanism used in the manufacture of semiconductor devices.

BACKGROUND TECHNOLOGY A semiconductor device using a lead frame formed by press-molding a flat metal plate is manufactured by a mounting process in which a semiconductor pellet is placed and fixed on a pellet placement part of the lead frame, and a thin metal wire is used to connect the electrode on the pellet and the lead part of the lead frame. The lead frame is manufactured through a wire bonding process for making connections, a resin molding process for covering the main part including the pellets with a resin material, and a process for cutting unnecessary parts of the lead frame and separating it into individual semiconductor devices.

Here, the lead frame is easily bent, and when stored or moved between processes, a plurality of lead frames are stored in a magazine and protected. In particular, in the lead frame after the wire bonding process, the pellet and the lead part are connected by a thin metal wire, so the thin metal wire is stretched due to flexure, and the loop of the thin metal wire is deformed and may come close to or come into contact with an undesired part. This may cause defects such as a drop in withstand voltage and short circuits, or even breakage of the thin metal wire, which may cause disconnection defects, so care must be taken when handling.

On the other hand, in a mounting process or a wire bonding process, the lead frame is fed forward by a constant pitch by a feeding mechanism.

An example of this feeding mechanism is shown in FIGS. 1 and 2. In the figure, reference numeral 1 denotes a lead frame, in which guide holes 1a are bored at a constant pitch along the longitudinal direction. A guide rail 2 guides the lead frame 1 on which the lead frame 1 is placed and restricts movement in the short side direction, and has a long hole 2a formed along the movement path of the guide hole 1a. Reference numeral 3 denotes a guide pin that passes through the elongated hole 2a of the guide rail 2 and engages with the guide hole 1a of the lead frame 1. The guide pin 3 is connected to an elevating movement device (not shown) and repeats ascending, advancing, descending, and retreating. The forward motion causes the guide pin 3 to engage with the guide hole 1a, thereby advancing the lead frame 1 by a certain pitch.

In this device, the lead frame 1 is supported by the guide rail 2, so there is no bending or twisting of the lead frame, and by arranging the magazine at the front and rear ends of the guide rail 2, there is no need to touch it during work. This prevents deformation and breakage of the thin metal wire.

Incidentally, in order to fully automate the process, it has been considered to automatically supply lead frames even in the resin molding process, but the apparatus shown in FIG. 1 cannot be immediately applied to this process. The reason for this is that in the resin molding process, a jig is placed below the lead frame to position and mount multiple lead frames within the mold cavity.
This is because the guide pin cannot be placed below the guide rail.

Therefore, if the guide pin 3 is arranged above the guide rail 2 as shown in FIGS. 3 and 4, it is possible to feed the lead frame 1 without being hindered by the alignment jig.

However, in this case, the following problem occurred. That is, when the guide pin 3 is lowered and inserted into the guide hole 1a of the lead frame 1, and then moved forward to be pulled out from the guide hole 1a and then retreated, the friction between the guide pin 3 and the guide hole 1a causes As a result, the lead frame 1 was lifted, causing the lead frame 1 to be bent or twisted, and the thin metal wires to be deformed or broken.

Regarding this point, in the apparatus shown in FIG. 1, there was no problem because the guide rail 2 acted as a stopper for the lead frame 1 when the guide pin 3 was pulled out from the guide hole 1a.

Therefore, a stopper that presses the lead frame 1 when the guide pin 3 is raised may be provided, but it must be placed on the same surface as the guide pin 3, which is undesirable because the mechanism becomes complicated.

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above problems.
To provide a feeding device having a simple structure and capable of smoothly extracting a guide pin.

The present invention has a moving device that reciprocates over a certain distance along a lead frame conveyance path, and a lifting device that moves a guide pin up and down above the conveyance path and engages with a guide hole of the lead frame. The lead frame is advanced by a certain pitch by engaging with the guide hole, and when the guide pin is raised and removed from the guide hole, the moving device is moved back a minute distance to separate the front end of the guide pin from the inner peripheral surface of the opposing guide hole. It is characterized in that the pin is raised and the moving device is moved backward.

According to the present invention, the structure is simple, and when the guide pin is engaged with the guide hole of the lead frame and moved forward to remove the guide pin from the guide hole, there is no bending or twisting of the lead frame, and the connection is made on the lead frame. It is possible to prevent loop deformation and breakage of thin metal wires.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be explained below starting from the apparatus shown in FIGS. 5 and 6. In the figure, reference numeral 4 denotes a guide rail that supports and guides the lead frame 1. Although not shown in the figure, a magazine in which a plurality of lead frames 1 are arranged in a row is stored in the rear, and a magazine in the front is supplied with the lead frame 1 positioned in the cavity of the mold. There are jigs for each. 5 is a screw shaft arranged along the guide rail 4, and a nut 6 is screwed onto it. This nut 6 also has two guide rods 7,
7 penetrates through to prevent inclination. A rotating device (not shown) is connected to the screw shaft 5 and rotates to move the nut 6. This screw shaft 5 and nut 6 form a moving device. 8 is Natsu 6
An arm 9 extending from above onto the guide rail 4 is a cylinder (elevating device) that is supported by the arm 8 and moves the connecting body 10 up and down.Both ends of the connecting body 10 are prevented from tilting by guide rods 11, 11.
Reference numeral 12 denotes a guide pin extending downward from the lower surface of the connecting body 10, and protrudes at a constant pitch on the movement locus of the guide hole 1a of the lead frame 1. Further, the tip of the guide pin is tapered to facilitate insertion.

This operation will be explained below with reference to FIGS. 7 to 10. First, as shown in FIG. 7, a guide pin 12 is inserted into a guide hole 1a' of a lead frame 1' pushed out from a magazine (not shown) onto a guide rail 4.
lower and engage. Then, as shown in FIG. 8, the moving device is operated to advance the lead frame 1' by a fixed pitch. At this time, the outer peripheral surface of the guide pin 12 in its advancing direction is in contact with the inner peripheral surface of the guide hole 1a'. Next, as shown in FIG. 9, the screw shaft 5 is reversed so that the contact surfaces between the guide pin 12 and the guide hole 1a' are separated, and as shown in FIG. 10, the guide pin 12 is pulled out from the guide hole 1a'. Furthermore, the screw shaft 5 is reversed to return the guide pin 5 to its initial position. At this position, the next lead frame is pushed out from the magazine, and the above operation can be repeated to advance the lead frames in sequence.

The amount of reverse rotation of the screw shaft 5 before raising the guide pin 12 is larger than the amount of backlash that occurs between the screw shaft 5 and the nut 6,
The setting can be made within a range that does not exceed the clearance margin between a', and if the guide pin 12 and the guide hole 1a' are even slightly separated, the screw shaft 5 can be reversed while raising the guide pin 12.

Since the guide pin 12 has a tapered tip, when the tapered portion comes between the inner peripheral surfaces of the guide hole 1a', the lead frame 1' and the guide pin 12 are in a non-contact state. The screw shaft may be reversed at high speed by detecting non-conduction between the guide pin 12 and the guide pin 12.

The lead frames 1' that have been intermittently fed on the guide rails 4 in this manner are sequentially supplied onto a lead frame arrangement jig placed in front.

As described above, according to the present invention, the guide pin is engaged with the guide hole of the lead frame from above and moved forward, the guide pin is pulled out from the guide hole, the guide pin is retreated, and the guide pin is inserted into the guide hole of another lead frame again. In a device that intermittently feeds a lead frame by repeatedly engaging and advancing a guide pin, the lead frame does not lift up when the guide pin is removed from the guide hole, so the lead frame does not bend or return. Deformation and disconnection of the loop of metal thin wire connected to the lead frame can be prevented, and a stopper to prevent the lead frame from floating is unnecessary, making the structure simple.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of a lead frame feeding device, FIG. 2 is a side view taken along line A-A in FIG. 1, and FIG. 3 is a side sectional view showing an example of a lead frame feeding device which is the premise of the present invention. 4 is a sectional view taken along the line B-B in FIG. 3, FIG. 5 is a side sectional view showing an example of the device according to the present invention, FIG. The figure shows a side sectional view of a main part for explaining the operation of the apparatus shown in FIG. 1'...Lead frame, 1a'...Guide hole,
5, 6...Movement device, 9...Elevating mechanism, 12...
guide pin.

Claims (1)

[Claims] 1. In a moving device that reciprocates along a lead frame conveyance path, a lifting device that moves a guide pin up and down on the conveyance path and engages with a guide hole of the lead frame is fixed, and the guide pin is engaged with the guide hole. At the same time, the lead frame is advanced by a certain pitch, and when the guide pin is raised and removed from the guide hole, the moving device is moved back a minute distance to separate the front end of the guide pin from the inner peripheral surface of the opposing guide hole, and the guide pin is raised. A lead frame feeding device characterized in that a moving device is configured to move backward.