JPH0427698B2 - - 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 elements such as CPUs and microprocessors.

[Technical background of the invention and its problems] A semiconductor resin sealing device is a device that covers and seals various semiconductor pellets mounted on a lead frame with a resin to protect them.
In a typical configuration, a lead frame is inserted between a lower mold and an upper mold, a semiconductor element is positioned in a pair of cavities provided in each of the lower mold and upper mold, and a runner or gate part is connected to each cavity. The molten resin is press-fitted through the hole.

In conventional semiconductor resin encapsulation equipment, a tablet-shaped molding resin is placed in a pot of a mold, heated and melted in the mold, and then pressed into the pot with a plunger. However, heating a tablet to its melting temperature (170 to 190°C) takes approximately several seconds to more than ten seconds, depending on the size of the tablet. In order to perform the molding operation efficiently, it is preferable to shorten the molding time required from resin injection to curing as much as possible. In general, it was difficult to shorten the time from injection to heating, so measures were taken such as mixing a curing accelerator into the mold resin to increase the curing speed.
However, this method is not preferred because it reduces the moisture resistance of the product. Furthermore, if an attempt is made to shorten the heating time by increasing the heating temperature, there are problems such as internal cavities occurring in the resin and non-filling occurring.

Therefore, before inserting the tablet into the pot of the mold, the tablet is preheated to a semi-molten state, and the preheated molded resin is passed through the pot of the resin sealing device. The molding cycle time has been shortened by guiding the mold into the pot of the mold.

Here, a preheating device that uses high frequency (750 MHz) heating (so-called high frequency heating) is generally used.

However, in this case, if you try to insert the semi-molten tablet into the pot of the resin sealing machine mechanically, the tablet may get stuck in the machine and fail, so manual labor is required. I become confused. When handled by humans in this way, not only does the reliability of thermal shock and other problems increase from shot to shot, but there are also problems such as a certain percentage of defective products being included. .

[Purpose of the invention]

Therefore, the present invention enables the tablet to be mechanically transported in a solid state by preheating the tablet directly above the pot of the mold and dropping the preheated tablet directly into the pot of the mold. To provide a device which allows a preheated tablet to be guided into a pot of a mold without manual intervention.

[Summary of the invention]

In order to achieve the above object, the resin sealing device of the present invention uses a plunger to press-fit molten mold resin into the cavity of a molding die consisting of an upper mold and a lower mold through a pot or a gate part. In the resin sealing apparatus for semiconductor devices, a mold resin supply is provided in an upper mold part that holds the upper mold so as to communicate with a pot or a gate part of the molding mold, and extends in the vertical direction through which the plunger can be inserted. a guide; a waveguide for preheating mold resin, the end of which is disposed within the upper mold part and extends outward, and through which the mold resin supply guide passes; and a waveguide connected to the outwardly projecting end of the waveguide. a microwave generator that supplies microwaves to the waveguide; and an opening/closing device that opens and closes an opening of the mold resin supply guide at a position below the waveguide. be.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a semiconductor device resin sealing apparatus according to the present invention will be described based on the drawings.

FIG. 1 shows a partially cutaway front view of a resin sealing device according to the present invention, and FIG. 2 shows a side view thereof. This device basically consists of an upper mold part 1 and a lower mold part 2 which can be separated from each other, and the lower mold part 2 is adapted to move up and down by hydraulic pressure or the like. An upper mold 4 is provided on the lower surface of the upper support frame 3 of the upper mold part 1, and a lower mold 6 is provided on the upper surface of the lower support frame 5 opposite to this. A pair of recesses 7 and 8 are provided on the opposing surfaces of each of the upper and lower molds 4 and 6 so that a cavity is formed when they are brought together, and for example, the upper mold 4 is connected to a pot 9 to guide molten resin. A gate portion 10 is formed. This structure is no different from a conventional general resin sealing device. The difference is that a preheating device using a waveguide is provided.

That is, the upper mold part 1 is provided with a supply guide 12 that communicates with the pot 9 from the upper end of the upper support frame 3 and supplies a molding resin (hereinafter referred to as a tablet) 11. This supply guide 12 is connected to a plunger 1 which descends toward the pot 9 from above.
3 has an inner diameter through which it can be inserted. Further, a waveguide 16 is interposed between the upper part 14 and the lower part 15 of the upper support frame 3, and the supply guide 12 is formed to pass through the waveguide 16 at a predetermined position. .

The waveguide 16 is, for example, a rectangular waveguide, and is connected via a circulator 17 to a microwave generator 18 such as a magnetron. The circulator 17 is for preventing loss of radiated power due to interference with radiated radio waves caused by reflected waves from the resin sealing device side reflecting back to the microwave generator 18 side, and is equipped with a non-reflection terminator 19. . The end of the waveguide 16 is formed with a reflective end, and the supply guide 12 is 1/4λg (λg is the wavelength of the microwave used) from the end.
It is located at the location of The reason is the waveguide 16
This is to align the center of the peak of the electric field distribution due to the standing waves generated within the tablet 11 with the tablet 11, thereby making effective use of the radiated power. Furthermore, by aligning the central portions of the peaks of the electric field distribution, the inside of the tablet 11 is heated more than the outer periphery, so that the inside of the tablet 11 can be preheated to a required temperature without being deformed. As a result, it is possible to prevent the delay in increasing the internal temperature of the resin when heating without preheating as in the conventional method.
It is possible to prevent the occurrence of internal cavities and shorten the molding time. A guide 20 made of a non-dielectric material such as Teflon (trade name) is provided in the supply guide 12 portion of the waveguide 16, and the tablet 11 introduced into the supply guide 12 is guided inside the waveguide 16. I'm trying not to get into it. An opening/closing device 21 is provided at the lower end of this guide 20 to open and close the opening, and when it is closed, the tablet 11
is held within the waveguide 16.

Next, the operation will be explained. First, when the tablet 11 is put into the supply guide 12 from the conveyance guide, the tablet 11 remains in the waveguide 16 because the opening/closing device 21 is closed at this time. At this time,
The tablet 11 is preheated by radiating microwaves (eg, 2450 MHz). As mentioned above, the preheating state is such that the internal temperature of the tablet 11 is high and the outer circumference is relatively low. When preheating is completed, the opening/closing device 21 is opened and the tablet 11 is opened.
is dropped into pot 9. Next, the resin is heated by the lower mold 6, and when it melts, the plunger 13 is inserted into the supply guide, and the pressure of the plunger 13 forces the molten resin into the cavities 7 and 8 through the gate 10. At this time, since the tablet 11 has been preheated, it reaches the melting temperature quickly, and there is no need to forcefully heat it to a high temperature, which prevents the formation of internal cavities, ultimately shortening the molding time and improving the quality of the product. can be ensured.

In the above embodiments, the waveguide was used as a reflective termination, but
It may also be a non-reflection termination. By doing so,
Attenuation of radiated power due to reflected radio waves at the terminal can be prevented. Further, although the case where there is one supply guide 12 has been described, in the case of a multi-plunger type device, the above-mentioned configuration may be provided for each plunger, and it is applicable.

〔Effect of the invention〕

As described above, according to the present invention, the tablet is mechanically conveyed in a solid state and put into the mold resin supply guide, and the waveguide and After being preheated using a microwave generator, the preheated tablet can be directly dropped into the pot of the mold via an opening/closing device, allowing it to be preheated without any manual intervention. The tablet can be guided into the pot of the mold. This has the effect of stabilizing the molding of each shot and improving the reliability of the molded product yield and thermal shock resistance.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing the structure of a resin sealing device for a semiconductor element according to the present invention, and FIG. 2 is a side view thereof. 1... Upper mold part, 2... Lower mold part, 4... Upper mold part,
6... Lower mold, 7... Cavity recess, 8... Cavity recess, 11... Tablet, 12... Supply guide, 13... Plunger, 16... Waveguide, 18... Microwave generator, 21...Switching device.

Claims (1)

[Scope of Claims] 1. A resin encapsulation device for a semiconductor element in which molten mold resin is press-fitted by a plunger into a cavity of a molding die consisting of an upper die and a lower die through a pot or a gate portion, comprising: a mold resin supply guide that is provided in an upper mold part that holds the upper mold part so as to communicate with the pot or gate part of the molding die, and extends in the vertical direction through which the plunger can be inserted; a waveguide for preheating the mold resin, which is disposed in the waveguide and extends outward, and through which the mold resin supply guide penetrates; A resin sealing device for a semiconductor element, comprising: a microwave generator for supplying microwaves; and an opening/closing device for opening and closing an opening of the mold resin supply guide at a position below the waveguide.