JPH056347B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a resin sealing device used for manufacturing semiconductor devices such as CPUs and microprocessors.

[Technical background of the invention]

As shown in FIG. 1, the semiconductor resin encapsulation device is
This is a device that seals a semiconductor pellet (not shown) mounted on a lead frame 1 with a resin 2 to protect it, and is generally designed to seal with a plurality of resins.

As shown in FIG. 2, the semiconductor resin encapsulation device has the following features:
Basically, an upper mold 3 and a lower mold (or mold) 4 paired with the upper mold 3, a lead frame loader 5 that moves in and out between the upper mold 3 and the lower mold 4 to load and unload the lead frame, It also consists of a tablet loader 7 that inserts a tablet (molded sealing resin into a cylindrical shape or the like) into a pot 6 provided in the lower mold 4.

FIG. 3 is a plan view of the lower mold 4, in which a plurality of cavities 8 and resin injection pots 6 are provided between adjacent cavities 8 on the surface facing the upper mold 3. Although not shown, the upper mold 3 is also provided with a similar cavity corresponding to the cavity 6 of the lower mold 4. Note that 9 is a gate for introducing the resin in a fluid state from the pot 6 into the cavity 8.

Next, the operation will be explained. First, upper mold 3 rises,
A lead frame loader 5 enters between the upper mold 3 and the lower mold 4 and carries the lead frame 1 into the lower mold 4. Next, after the lead frame loader 5 retracts the tablet, the tablet loader 7 carries the tablet and drops it into the pot 6. At this time, the lower mold 4 is heated to a temperature (180℃) that can melt the tablet into a fluid state.
is heated to. Next, tablet loader 7
After the upper mold 3 is retracted, the upper mold 3 is lowered and combined with the lower mold 4. As a result, a cavity having a shape corresponding to the resin part 2 in FIG. 1 is formed by the mutual cavities 6 on the mating surfaces of the upper mold 3 and the lower mold 4. Next, the plunger provided in the pot 6 rises to push up the fluid resin, and injects the fluid resin into the cavity through the gate 9. Once the injection is complete, the resin hardens quickly as it is thermosetting. Next, the upper mold 3 is raised, and the resin-sealed semiconductor device is taken out in the manner shown in FIG. 1, thereby completing the sealing process. It should be noted that the chips are separated into chips in a subsequent step, but since this is not related to the present invention, a description thereof will be omitted.

[Problems with background technology]

In the semiconductor resin encapsulation device described above, pot 6
After the tablet is inserted into the mold, it takes several seconds to ten-odd seconds for the tablet to reach the melting temperature (170-190°C) from room temperature. This time will vary depending on the size of your tablet. In order to shorten the molding cycle time from the standpoint of improving productivity, it is necessary to shorten the time required for the resin to thermoset. Therefore, a method is generally adopted in which a curing accelerator is mixed into the resin to increase the curing speed. However, this curing accelerator is undesirable because it reduces the moisture resistance of the product.

On the other hand, when heating the resin tablet in the lower mold 4, it inevitably takes a certain amount of time, and if the heating is insufficient, voids will occur inside, leading to product defects. This becomes a particular problem when using large tablets such as microprocessors. In addition, raising the heating temperature makes it possible to shorten the heating time, but it also destabilizes the molding conditions, and flame retardants such as brominated epoxy mixed in the resin decompose, impairing the reliability of the product. There is a risk.

Another possible way to shorten the molding cycle time is to speed up the injection time of the fluidized resin, but the molding pressure builds up before the center of the tablet is fluidized, causing resin to adhere to the plunger. The problem arises.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor resin encapsulation device that can shorten molding time without adversely affecting resin molding.

[Summary of the invention]

In order to achieve the above object, the present invention provides a preheating means for preheating the resin to a semi-molten state or to a critical melting temperature before charging the resin into a pot, in a resin supply device such as a tablet loader that supplies sealing resin. The resin supply device is characterized in that it is provided in the same mechanism as a lead frame loader that positions the lead frame between the upper mold and the lower mold and positions the part to be sealed in the cavity. .

Here, as the sealing resin, in addition to the one molded into a tablet, powder-like powder can be used. Therefore, the resin supply device should be configured depending on whether the resin is in the form of a tablet or powder. As the preheating means, an electric heater built into the supply device, a hot air supply device, a microwave oven, or the like is used.

[Embodiments of the invention]

Hereinafter, the present invention will be described in detail based on illustrated embodiments. In this example, since the basic configuration of the semiconductor resin encapsulation device remains the same, FIG.
FIGS. 2 and 3 are used in the following explanation.

FIGS. 4A to 4D show an overview of the semiconductor resin encapsulation device and the encapsulation process according to the present invention. As shown in FIG. 4, the tablet loader 5A has the same mechanism as the lead frame loader, and has preheating means 10 inside. In this case, the tablet loader 5A can have various configurations such as vacuum suction for the tablet 11, clamping the tablet 11 with a chuck, or providing a shutter on the lower surface of the holding hole 12. Furthermore, a similar mechanism for holding the lead frame loader using claws may be used. However, it is important to configure the tablet loader 5 and the lead frame loader to operate at the same timing. This is because the purpose is to shorten molding time. Further, as the preheating means 10, as described above, an electric heater, a hot air device, a microwave oven, etc. may be used.

Next, the molding process will be explained step by step based on FIGS. 4A to 4D. First, raise the upper mold 3 and
The tablet loader 5A is carried between the lower mold 4 and the lower mold 4 (FIG. 4A). At this time, the tablet 11 and the lead frame 1 are set in the tablet loader 5A, and are therefore carried in at the same time. Further, the tablet loader 5A uses the preheating means 10 to set the lower limit of the B-stage temperature (70 to 120°C), that is, 70°C.
Due to the heat, the tablet 11 is in a semi-molten state (solid state) and reaches 70 degrees Celsius inside.
is preheated evenly.

Next, the tablet loader 5A loads the tablet 1
1 and the lead frame 1 are released, the tablet 11 is put into the pot 6, and the lead frame 1 is placed at a predetermined position on the lower mold 4 (the fourth
Figure B).

Next, the tablet loader 5A is moved backward, and the upper mold 3 is lowered to be placed and fixed on the lower mold 4 (the fourth
Figure C). At this time, the tablet 11 is in a fluid state in the pot 6 because the lower mold 4 has already been heated to a melting temperature. The time to reach this fluid state is faster than in the past. This is because it has been preheated.

Next, the plunger 13 is raised to apply pressure to the fluidized resin 11A. Then, the resin 11A is injected into the cavity 8 through the gate 9 (see FIG. 3), and eventually becomes thermoset.

Next, the upper mold 3 is raised and the molded lead frame is taken out. As a result of this molding, what is shown in FIG. 1 is produced. Thereafter, new molding is sequentially performed in the same manner.

In the above embodiments, the sealing resin is used as a tablet, but powder may also be used. In that case, the loading mechanism of the tablet loader 5A may be modified as necessary to match the powder. The effects differ depending on whether the resin is made into tablets or powder. If it is made into a tablet, it will be easier to position and handle when loading, and it will also be easier to measure. However, it takes time and effort to mold. On the other hand, when it is made into a powder, there is no need for molding and there is an advantage that the heating temperature is uniformly transmitted.

〔Effect of the invention〕

As described above, according to the present invention, the following effects are obtained by providing the resin supply device with the preheating means.

(1) Since the resin is already preheated before it is put into the pot, it can be brought to a molten state in a short time after it is put into the pot. Therefore, it contributes to shortening the molding time. This requires a large amount of resin, especially when molding large chips;
This is effective when heating takes that much time.

(2) Furthermore, it is not necessary to use a large amount of heat curing accelerator, so the quality of the product can be improved.

(3) In addition, the above-mentioned conventional drawbacks can be solved.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of resin-sealing semiconductor pellets on a lead frame, Fig. 2 is an elevational view showing the basic configuration of the semiconductor resin sealing device, Fig. 3 is a plan view of the lower mold, FIGS. 4A, B, C, and D are longitudinal cross-sections showing an embodiment of a semiconductor resin sealing device according to the present invention. 1... Lead frame, 2... Solidified resin,
3... Upper mold, 4... Lower mold, 5A... Tablet loader, 6... Pot, 8... Cavity, 10...
...preheating means, 11...tablet, 13...plunger.

Claims (1)

[Scope of Claims] 1. A resin supply device that supplies resin into pots provided in the upper mold and/or the lower mold is provided with preheating means for preheating the resin to a semi-molten state or to a critical melting temperature, Semiconductor resin encapsulation characterized in that the supply device is provided in the same mechanism as a lead frame loader that positions the lead frame between the upper mold and the lower mold and positions the part to be sealed in the cavity. Device. 2. In the device according to claim 1,
A semiconductor resin sealing device characterized in that preheating means is a built-in heater. 3. In the device according to claim 1,
A semiconductor resin encapsulation device characterized in that preheating means is a hot air device. 4. In the device according to claim 1,
A semiconductor resin sealing device characterized in that preheating means is a high frequency heating device. 5. A semiconductor resin encapsulation device according to claim 4, wherein the high frequency heating device is a high frequency induction heating device. 6. In the device according to claim 4,
A semiconductor resin sealing device characterized in that the high frequency heating device is a high frequency dielectric heating device. 7. A semiconductor resin encapsulation device according to any one of claims 1 to 6, characterized in that the encapsulation resin is molded into a tablet shape. 8. A semiconductor resin encapsulation device according to any one of claims 1 to 6, wherein the encapsulation resin is in powder form.