JPH0472641A - Resin sealing and molding method of semiconductor element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a resin sealing molding method for semiconductor elements such as ICs and LSIs.

2. Description of the Related Art An example of a conventional method for molding a semiconductor element with resin will be described below with reference to the drawings. As shown in FIG. 3, the lower mold 22 of the resin sealing mold includes a pot 23, which is a hole for introducing the sealing resin, and a plunger 24, which is slidably held within the pot. An upper mold 21 is waiting above the lower mold 22. The lead frame 29 to which the semiconductor element 30 is attached is placed on the cavity 26 of the lower mold 22. At the same time or after a short time, resin tablet 3 is formed into a cylindrical shape by pre-pressurizing the sealing resin.
1 into the pot 23, and the space between the upper mold 21 and the lower mold 22 is closed (FIG. 4). At this time, the upper mold 21, the lower mold 22
has a built-in heater (not shown) and has a heating capacity of 160 to 180
℃, the tablet 31 receives heat from the inner circumferential surface of the pot 23 and begins to melt from the outer circumferential surface. At the same time, the plunger 24 is raised and pressurized. Due to this pressurization, the molten resin flows into the cavity 2 provided in the upper mold 21 and the lower mold 22.
On 5.26, Cal 28. It is filled and molded through the runner gate 27.

Problems to be Solved by the Invention As mentioned above, in the conventional resin sealing molding method for semiconductor elements, the resin tablet 31 is heated only from the inner peripheral surface of the pot 23, so the resin tablet 31 is heated before it melts to the inside. Often pressurized.

As a result, the operation of the plunger 24 becomes defective, and the product is likely to have voids or wires to fall. Therefore, in order to melt the inside of the resin tablet 31,
The resin tablet 31 was kept in the pot 23 for a certain period of time and then pressurized.
Since the outer circumferential portion of the resin tablet 31 that is in contact with the inner circumferential surface of the resin tablet 31 has already begun to harden when pressurized, the operation of the plunger 24 will also be malfunctioning in this case, causing voids to occur in the product and wires to fall. It was easy. In the conventional method, furthermore, the air contained in the resin tablet 31 from the beginning remains in the product as voids.
It also caused product quality defects.

Means for Solving the Problems The technical means of the present invention for solving the above problems are as follows:
In order to sufficiently preheat the resin without causing curing, the resin is preheated by electromagnetic dielectric heating with moisture added to the supplied resin. After heating is completed, the air and moisture originally contained in the resin are removed by pressurizing the resin under reduced pressure.

For production The effects of the technical means of the present invention are as follows.

That is, when water added to the resin in advance is subjected to electromagnetic dielectric heating, the water is heated by the electromagnetic waves, and the heat is transferred to the resin, thereby preheating the resin uniformly and in a short time.

Moreover, since this preheating is performed using heated water, the resin does not harden. When the resin is dropped into the mold pot, it receives further heat from the inner peripheral surface of the pot as before, so that the resin is sufficiently uniformly molten during pressure molding of the plunger. Next, when preliminary pressurization is performed under reduced pressure, air and moisture contained in the resin are completely removed.

Example Embodiments of the present invention will be described based on FIGS. 1 and 2.

As shown in FIG. 1, the resin encapsulation molding device used in the present invention is equipped with a resin supply device 1, into which a resin tablet 5 to which water has been added in advance is placed, and then an electromagnetic wave shield is applied to the inner surface. - Electromagnetic waves are radiated into the case 2 via the waveguide 6 from a high frequency power source 7 (magnetron). At this time, the resin supply device 1
For example, since it is made of a material such as ceramic that transmits radio waves, the electromagnetic waves act on the water contained in the resin 5 in the resin supply device 1. Thereby, the moisture is heated and the heat is efficiently and uniformly transferred to the resin 5 in a short time. Thereby, the resin 5 is heated to the preheating temperature. After the resin 5 is preheated, it is pre-pressurized by the pressurizing means 3 provided in the resin supply device 1. At the same time, a vacuum is drawn from the suction port 8 provided in the case 2 to reduce the pressure inside the case 2. Then, the air contained in the resin 5 and the water added in advance for preheating are completely removed. At this time, the inner wall 4a of the resin supply device 1 is made of a material that allows radio waves to pass through, and at the same time is porous, and each hole communicates with the inner wall 4a, so that air, etc. can pass from one direction to the other. It has a structure. Therefore, the air and moisture can be removed without any problem.

After that, as shown in FIG. 2, the shutter 4b provided at the bottom of the resin supply device 1 is opened, the bottom shutter 19 of the case 2 is also opened, and the pressure means 3 is applied to the lower mold 10. The preheated and prepressurized resin 20 is dropped into the resin injection hole (pot 12). Then, the upper mold 9 and the lower mold 10 are closed. The dropped resin 20 is
Since it is already in a semi-molten state or a melting limit state due to preheating, the plunger 11 provided in the lower mold 10
When pressurized by the rise of the plunger 11, it is filled and molded into the cavity 13, 14 without interfering with the operation of the plunger 11. In the figure, 17 is a lead frame, and 18 is a semiconductor element.

The above embodiments have been explained in the case where the resin supply device has one supply section, but in the case of a multi-plunger, it can be similarly applied if the supply section is provided in multiple stages corresponding to each plunger and pot. It is.

This embodiment has been explained for the case of the lower plunger type, but in the case of the upper plunger type, the resin supply device is configured to be disposed above the upper mold pot after mold clamping. do it.

As another example, instead of attaching the resin supply device to the molding equipment itself, it is also possible to preheat and prepress the resin at another location and then supply it into the mold pot. It is.

Furthermore, regarding the resin, it is also possible to add water to granular resin instead of preparing resin tablets to which water has been added in advance.

Effects of the Invention According to the present invention, the resin can be sufficiently preheated before the resin sealing molding of the semiconductor element, and the resin is not hardened, so the operation of the plunger does not become unstable. , it is possible to provide molded products without voids and without wire collapse. In addition, since air is removed sufficiently, we can provide products that do not cause quality defects.

[Brief explanation of drawings]

FIGS. 1 and 2 are front cross-sectional views of a molding device equipped with a resin supply device used in an embodiment of the resin-to-soil molding method for semiconductor devices according to the present invention, according to the order of process steps. 3 and 4 are front sectional views showing a molding apparatus used in a conventional example according to the order of process steps. 1... Resin supply device, 2... Case,
3... Pressure means, 4... Shutter
5...Resin, 7...High frequency power supply, 9.
...Upper mold, 10...Lower mold, 11...
... Plunger 12 ... Pot, 13
゜14...Cavity, 17...Lead frame, 18...Semiconductor element. Name of agent: Patent attorney Shigetaka Awano and one other person (The first cause

Claims (1)

[Claims] (1) Before supplying the sealing resin into the molding die, the resin is preheated by applying electromagnetic dielectric heating to the resin with water added in advance, and the resin is heated after the preheating is completed. A resin encapsulation molding method for semiconductor devices, which includes a step of applying pressure under reduced pressure to remove air and moisture contained in the resin.