JPH0825402A - Encapsulation molding method - Google Patents

Abstract

PURPOSE:To provide a method for encapsulation-molding which has high quality, and excellent yield. CONSTITUTION:Since plasticized thermosetting resin is charged in a cavity 4, the resin cured in the cavity 4 is removed from molds and cut in a predetermined size including inserts I to obtain individual products, problems such as void, pinhole, charging failure, etc., of prior art can be effectively prevented, a product of high quality can be obtained. The ratio of the quantity of the used resin of the product is raised, the quantity of the discarded resin is reduced, and hence the yield of the resin can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing molding method for sealing an insert with a thermosetting resin.

[0002]

2. Description of the Related Art FIG. 6 shows a schematic view of a transfer molding machine used for this type of sealing molding. In the figure, 11 is an upper mold, 12 is a lower mold, 13 is a pot, 14 is a runner, 15 is a gate, 16 is a cavity, 17 is a gas vent, 18 is a plunger, T is a tablet, and I is an insert.

The runner 14 is branched from the pot 13, and as many cavities 16 as the number of the runners are provided at the branch end of the runner via a gate 15. Each cavity 16 conforms to the size of one product, and one insert I is arranged in each cavity 16 in the mold open state. The tablet T is formed by pressing a thermosetting resin powder into a cylindrical shape, and has a diameter slightly smaller than the pot diameter.

The upper mold 11 and the lower mold 12 are kept at a temperature suitable for plasticizing and hardening the thermosetting resin by a heater or the like, and the tablets T put in the pot 13 are plasticized by receiving heat. . The plasticizing resin is pressurized by the plunger 18, passes through the runner 14 and the gate 15, and is filled in each cavity 16, and further receives heat in the cavity 16 to be hardened.

After molding, the resin (product) hardened in each cavity 16 is taken out from the mold together with the cull part and the runner part, each product is separated at the gate position, and the runner part and the cull part are discarded.

[0006]

In the conventional encapsulation molding method described above, as shown in FIGS. 7 (a) and 7 (b), when the resin Pm flows into the bent portion of the runner 14, the gate 15, etc. , The flow velocity is locally increased and the air A is involved,
There is a problem that this appears as voids and pinholes inside and on the surface of the product.

When the plasticizing resin is filled in the cavity 16, the gate 15 is clogged with filler lumps in the resin or burrs generated in the previous shot, which impedes the flow of the resin and causes defective filling. Alternatively, as shown in FIG. 8, there is a problem that the air A is confined in the corner portion of the inner surface of the cavity 16 to cause the same filling failure.

Further, when performing the sealing molding as shown in FIG.
The amount of resin required at the time of molding corresponds to the volume of the product S, the runner portion Pr, and the cull portion Pk, but as described above, the runner portion Pr and the cull portion Pk are separated from the product S and discarded, so that one shot If the number of runner branches is increased or the product size is reduced in order to increase the number of products taken per product, there is a problem that the yield of the resin is reduced and the material cost is wasted.

The present invention has been made in view of the above problems, and an object thereof is to provide a high-quality and high-yield encapsulation molding method.

[0010]

In order to achieve the above object, the invention according to claim 1 fills a cavity in which an insert is arranged with a plasticized thermosetting resin material, and heat-cures the same. In a sealing molding method for sealing inserts, a cavity having a size capable of taking a plurality of pieces is used, and a plurality of inserts corresponding to the number of pieces are arranged in the cavity and filled with a plasticizing resin, and then the cavity is formed. It is characterized in that the resin cured inside is taken out of the mold and cut into a predetermined size including inserts to obtain individual products.

According to a second aspect of the present invention, in the sealing molding method according to the first aspect, an electronic component supported by a lead frame is used as an insert.

[0012]

In the present invention, individual products are filled by filling the cavity with the plasticized thermosetting resin, taking out the resin cured in the cavity from the mold, and cutting the resin into a predetermined size including the inserts. I am trying to get it.

By feeding the plasticized resin directly into the cavity without passing through a runner, a gate, etc., the resin filling speed into the cavity can be lowered, so that the filling speed is locally increased. By avoiding air entrainment, voids and pinholes caused by the air entrainment can be prevented.

Further, it is possible to avoid the clogging which has occurred in the same portion as in the conventional case where there is no gate and the resin filling speed is slow and the flow resistance is extremely small. Therefore, even if the resin contains a filler, The resin can be reliably filled up to the end. In addition, since the inner surface of the cavity has no corners except for the end portion, air trapping unlike the conventional case does not occur in the product area, and the problem of defective filling due to the air trapping can be prevented.

Further, since the ratio of the resin used to the product is high, the yield of the resin is good even when the number of products to be taken is increased or the product size is reduced, and the amount of resin to be discarded can be reduced as much as possible. It can greatly contribute to the reduction of material cost.

[0016]

1 is a schematic view of a transfer molding machine to which the present invention is applied. In the figure, 1 is an upper die, 2
Is a lower mold, 3 is a pot, 4 is a cavity, 5 is a gas vent, 6 is a plunger, T is a tablet, and I is an insert.

The mold of this embodiment does not have a runner and a gate as in the conventional case, and the cavity 4 is formed in a horizontally long shape extending from one side of the pot 3 to the gas vent 5. The cavity 4 has a size capable of taking a plurality of cavities 4, and a plurality of inserts I corresponding to the number of the cavities 4 are taken.
Are placed in the mold open state. By the way, FIG. 1 shows that six products can be obtained by one cavity 4.

The tablet T is formed by press-molding a powder of thermosetting resin such as epoxy, unsaturated polyester, phenol, diallyl phthalate into a cylindrical shape, and has a diameter slightly smaller than the pot diameter. are doing.

The upper mold 1 and the lower mold 2 are kept at a temperature suitable for plasticizing and curing the thermosetting resin by a heater or the like,
The tablet T placed in the pot 3 receives heat to be plasticized (see FIG. 1).

The resin Pm plasticized in the pot 3 is pressurized by the plunger 6 and filled in the cavity 4 while discharging the internal air from the gas vent 5, and after the filling, further heat is received in the cavity 4 to cure the resin. (See FIG. 2).

After molding, the resin P cured in the cavity 4
The s is taken out from the mold together with the cull portion Pk (see FIG. 3), and then cut into a predetermined product S including the inserts I (see FIG. 4). Various methods such as a mechanical method using a dicing machine and a physical method using a laser beam can be used for this cutting. The portion other than the product, that is, the end portion Pt1 corresponding to the cull portion Pk and the end portion Pt2 near the gas vent are discarded.

According to the above-mentioned encapsulation molding method, the plasticized resin is directly fed into the cavity 4 from the pot 3 without passing through a runner, a gate, etc., so that the resin filling speed into the cavity 4 can be lowered. It is possible to avoid air entrapment that has occurred due to locally high filling speed, and to prevent voids and pinholes caused by the air entrapment.

Further, since the conventional structure can avoid the clogging which occurs in the same portion without the gate, and the resin filling speed is slow and the flow resistance is extremely small, the cavity 4 can be filled even when the resin contains the filler. The resin can be surely filled up to the terminal end. Moreover, since there is no corner on the inner surface of the cavity 4 except for the vicinity of the gas vent, air confinement unlike the conventional case does not occur in the product area, and the problem of filling failure due to the air confinement is prevented. it can.

Further, since the ratio of the resin used to the product is high, the yield of the resin is good even when the number of products to be taken is increased or the product size is reduced, and the amount of discarded resin should be reduced as much as possible. It can greatly contribute to the reduction of material cost.

Furthermore, since a runner is unnecessary, the mold can be designed compactly, and many products can be molded with a small mold.

Furthermore, since the flow resistance of the resin is small, molding can be performed at a lower pressure than in the past, the mold clamping force has a margin, and it is easy to follow the increase in the number of products to be taken.

FIG. 5 shows an example in which the above-mentioned encapsulation molding method is applied to a package of electronic parts. In the same figure (a), a component body such as a capacitor whose both ends are supported by the lead frame F1 is sealed with a thermosetting resin, and the resin Ps cured in the cavity is cut at the broken line position in the figure. Then, the frame is removed, and a resin-packaged electronic component with leads is obtained. In the same figure (b), the IC substrate whose one side is supported by the lead frame F2 is sealed with a thermosetting resin, and the resin Ps cured in the cavity is cut at the position indicated by the broken line in the figure, and The frame frame is removed to form a resin-packaged IC with leads.

The present invention can be applied to molding methods other than the transfer exemplified in the embodiments, and similar effects can be obtained.

[0029]

As described in detail above, according to the present invention,
Fill the cavity with a plasticized thermosetting resin material,
Since the resin cured in the cavity is taken out from the mold and cut into a predetermined size including the inserts to obtain individual products, problems such as conventional voids, pinholes, and filling defects are eliminated. It is possible to reliably prevent and obtain a high quality product, and it is possible to improve the resin yield by increasing the ratio of used resin as a product among the used resin amount and reducing the discarded resin amount.

[Brief description of drawings]

FIG. 1 is a schematic view of a transfer molding machine to which the present invention is applied.

FIG. 2 is a diagram showing a filling operation.

FIG. 3 is a diagram showing a state after molding.

FIG. 4 is a diagram showing a state after cutting.

FIG. 5 is a diagram showing an example in which the molding and encapsulation method is applied to a package of electronic parts.

FIG. 6 is a schematic view of a conventional transfer molding machine.

FIG. 7 is a diagram for explaining problems of the conventional encapsulation molding method.

FIG. 8 is a diagram for explaining problems of the conventional encapsulation molding method.

FIG. 9 is a diagram for explaining problems of the conventional encapsulation molding method.

[Explanation of Codes] 1 ... Upper mold, 2 ... Lower mold, 3 ... Pot, 4 ... Cavity, 5
... gas vent, T ... tablet, I ... insert, S ...
Product.

Claims (2)

[Claims] 1. A sealing molding method in which a plasticized thermosetting resin material is filled in a cavity in which an insert is arranged, and this is heat-cured to seal the insert. Using a cavity with
After arranging a plurality of inserts in the cavity according to the number of pieces to be filled with the plasticizing resin, the resin cured in the cavity is taken out from the mold, and the resin is cut into a predetermined size including the inserts and cut into individual pieces. A sealing molding method, characterized in that the product of 2. The sealing molding method according to claim 1, wherein an electronic component supported by a lead frame is used as the insert.