JPS588585B2 - Lead frame attachment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead frame crimping device for crimping a lead frame to a substrate of a semiconductor integrated circuit case.

Conventionally, the crimping process of crimping a lead frame onto the substrate (hereinafter referred to as the base) of a glass-sealed ceramic case for semiconductor integrated circuits has been carried out manually.
As shown in FIGS. 3 and 5, the lead frame 8 was crimped using tweezers or the like to the base 14, which was coated with glass 31 heated on a heater block 30 and turned into a molten state. There are many problems such as damage, uneven positioning of the lead frame, inefficiency, and a heavy burden on workers, so mechanization has been a concern for some time.

Further, the surfaces of the leads of the lead frame 8 to which wire bonding is performed are not on the same plane due to manufacturing reasons, and there are always steps.

This level difference between the leads is caused by internal stress generated during the lead forming process, and it is considered difficult to eliminate the level difference unless the shape of the lead frame is changed.

When crimping is performed manually, the heated base 14
The lead frame 8 was placed in the proper position above using tweezers or the like, and the leads to be crimped were pushed into the molten glass with the tip of the tweezers while maintaining the heated state to obtain adhesion between the leads and the glass.

Therefore, even if there was a step between the leads, if the floating lead with the step was corrected with a bin set, the adhesion was completed.

If crimping is performed by machine, it will be necessary to install a mechanism that has the same function as the manual correction described above.

Moreover, when the level difference between the leads is corrected by this method, the level difference after crimping becomes smaller compared to the correction work using tweezers, and of course there is no damage to the leads caused by the tweezers.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lead frame crimping device that can replace conventional manual work, has high work efficiency, and does not suffer from the above-mentioned problems.

Next, embodiments of the present invention will be described with reference to the drawings.

Reference numeral 13 in FIG. 1 denotes a conveyor heater block, which has a rail function for the base 14 fed by the feed pawls 15 provided at the same pitch on the feed bar 12, and a heating function for the base 14.

The base 14 (see FIG. 5), which has been conveyed over the conveying heater block 13 with its back side touching, reaches the crimping position.
In this state, the glass 31 coated on the base 14 is in a molten state, so that the lead frame 8 can be pressure-bonded.

One-pitch feeding of the feed claw 15 that conveys the base 14 is performed by a cam (not shown).

A timing cam (not shown), which is provided on the camshaft and rotates at the same time as the cam, detects that the conveyed base is out of position, and the crimping process is started in response to the detection signal.

The lead frame crimping device according to the present invention includes a mechanism for arranging the lead frame 8 on the base 14 and a mechanism for pressing the lead frame.

The arrangement mechanism, whose sectional view is shown in FIG. 2, has a function of positioning one supplied lead frame 8 with respect to the supply body 1, and uses a magnet 20 to attract the lead frame 8 to the supply body 1. It has three functions: 1) positioning and arranging the suctioned lead frame 8 at a proper position on the base 4 that has been sent directly below the supply body 1 on the conveyance heater block 13;

The operation will be explained step by step.

The slide bar 6 is rotated in contact with the slide bar guide 7 as shown in FIG. Middle C
, the supplied lead frame 8 moves only in the C' direction.
is moved in the direction of the supply body 1.

The movement of the slide bar arm 9, the movement of the supply body 1, and the movement of the magnet upper and lower arms 4 are timed by cams (not shown) lined up on a single shaft, and the slide bar 6 is moved as shown in FIG. 1C. While moving in the direction, the magnet up/down arm 4 that applies a load to the magnet support bar 3 and the cam follower 5 fixed thereto rise, and at the same time, the magnet up/down compression spring 19 acts to move the magnet support bar 3 The mechanism is such that the magnet 20 driven into the magnet support rod 3 rises.

On the other hand, the positional relationship between the magnet support rod 3 and the supply body 1 is as shown in FIG. The magnet 20 does not attract the lead frame 8 in a state where the relative position with respect to the supply body 1 has not yet been determined.

The lead frame 8 that has been sent in is the lead frame guide 2.
Fig. 42b shows a state in which the supply body 2 and the lead frame 8 are in contact with each other and the relative position of the lead frame 8 is exposed.

The magnet support rod positioning pin 21 is driven into the magnet support rod 3, moves up and down simultaneously with the magnet 20, and determines the relative positional relationship between the magnet 20 and the supply body 1 when the magnet 20 is lowered.

In this state, the magnet upper and lower arms 4 descend, and the magnet 20 attracts the lead frame 8 whose relative position is exposed, and the second
The state shown in figure a is reached.

After this state is obtained, the slide bar 6 moves to C' in FIG.
When the slider 6 is completely removed from the supply body 1, the supply body 1 descends in the direction shown in FIG. 1D while adsorbing the lead frame 8 shown in FIG. The lead frame 8 is placed at a regular position with respect to the base 14.

At this time, the flat part of the supply body to which the lead frame 8 is attracted pressurizes the entire lead surface of the lead frame 8 and pushes it into the molten glass.

The supply body 1 is heated by a heater fitted into a heater hole 32 provided in the supply body 1, which moderately heats the lead frame, rapidly removes heat from the molten glass on the base when pressurized, and melts the glass. prevents it from becoming stuck.

After pressurization, before the supply body 1 rises in the direction D', the magnet upper and lower arms 4 rise, the magnet 20 separates from the lead frame 4, and the attraction of the lead frame 4 is released.

Since the supply body rises thereafter, the supply body 1 does not suck up the product.

The base, on which the lead frame 8 has been arranged as described above, is further heated and sent to the next pitch by the feed pawl 15.

If there is no step difference in the leads as described above, after the lead frame is placed by applying pressure with the supply body 1, the heated state is maintained, and the adhesion between the oxidized leads and the molten glass progresses, and the pressure bonding is completed.

Actually, the step in the lead occurs only in the long lead indicated by the number 33 of the lead frame 8 shown in FIG.

The lead frame 8 is usually formed from a 0.7 to 0.3 mm thick plate made of iron-nickel alloy.
It has spring properties.

Therefore, for leads with steps, supply body 1
If the supply body 1 is raised and the pressure is removed, the adhesion between the leads and the molten glass will progress and the glass will not be able to hold the lead frame 8, so the leads will be lower than the glass surface. It will lift up and the adhesion between the glass and the glass will be poor.

Therefore, if you apply pressure to the lead with a step while maintaining the heated molten state, as when crimping is done manually, there will be no adhesion failure, and if the third lead with the step has a
If the leads shown in FIG. 33 are pressed on the same plane, there will be no step difference in the leads after crimping, unlike when done manually.

In an embodiment according to the invention, the pressurization mechanism is driven to introduce high pressure air into a pneumatic cylinder.

As shown in FIG. 4, a pressurizing mechanism including a cylinder 16 is provided on the feed bar 12, and the pressurizing operation is started by a detection signal caused by driving the feed bar 12, like the supply arrangement mechanism, and is not shown. Pressure is applied for a period of time regulated by an electric circuit.

The pressurizing mechanism shown in FIG. 4 guides high-pressure air into the cylinder 16 and is operated by the pushing force of the piston rod 26 caused by the high-pressure air.

The pressurizing force of the pressurizing body 17 is adjusted by a pressurizing spring 25 actuated by a spring pushing plate 24 fixed to the piston rod 26, so that the force of the piston rod 26 does not directly act on the pressurizing body 17.

This keeps the pressing force almost constant.

After pressurization is applied, the high pressure air is extracted from the cylinder 16 and the piston rod 26 is lowered by the action of the return spring 27.

A return retainer 23 fixed to the piston rod 26 pulls up the pressurizing body 17 from the pressurizing surface to end pressurization.

Through the above operations, the oxidized lead and the molten glass are completely bonded, and upon cooling, the glass adheres to the lead, completing the crimping.

According to the lead frame crimping device according to the present invention, the step difference in the lead after the lead frame is crimped becomes smaller compared to when it is done manually, and wire bonding becomes stable.

In addition, damage to the lead frame is reduced, and the crimping position of the lead frame is made uniform, improving quality.

Furthermore, if a configuration like the present device is adopted, the lead frame crimping process can be fully automated, and the number of lead frame crimping steps can be reduced to zero.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the outline of the present device, Figs. 2a and 2b are cross-sectional views of the supply arrangement mechanism in Fig. 1 taken from arrow A, and Fig. 3 is a perspective view showing the conventional manual crimping state. , Figure 4 is the first
FIG. 5 is a cross-sectional view of the pressurizing mechanism as viewed from arrow B, and FIG. 5 is a perspective view showing the base targeted by the present device. In the figure, 1... Supply body, 2... Lead frame guide, 3... Magnet support bar, 4...
Magnet support rod, 5...Cam follower, 6...
...Slide bar arm, 7...Slide bar guide, 8...Lead frame, 9...
・Slide bar arm, 10...Slide bar arm axis, 11...Slide bar pin, 12.
...Feed bar, 13...Transportation heat block, 14...Base, 15...Feed claw, 16...Cylinder, 17. ... Pressure body, 18 ... Pressure body support, 19 ... Compression spring for magnet up and down, 20 ... Magnet, 21 ...
...Magnet support bar positioning pin, 22...Axis,
23... Return retainer, 24... Spring push plate, 25... Pressure spring, 26...
・Piston rod, 27... Return spring, 28.
... Cylinder cap, 29 ... Piping tube, 30 ... Heater block, 31 ...
...Glass, 32...Heater hole, 33...
...Base (after lead frame placement).

Claims (1)

[Claims] 1. In a lead frame crimping device for crimping a lead frame onto a substrate of a case for sealing a semiconductor integrated circuit device,
means for heating the substrate; and a supply mechanism for positioning the lead frame at a proper position on the heated substrate;
A lead frame crimping device comprising: a mechanism for pressurizing the lead frame supplied by the supply mechanism.