JPH071496A - Method and apparatus for molding - Google Patents

Abstract

PURPOSE:To prevent voids from being generated in a resin-molded article after molding by inclining a cavity when a material to be molded is packed therein, providing a gate at an end on a lower position side of the cavity and providing an air vent for discharging air at an end on a higher position side of the cavity. CONSTITUTION:When liquid resin 31 is packed in a cavity 23, the cavity 23 is inclined with respect to a horizontal plane, and the resin 31 introduced through a gate 28 opened on a lower position side of the cavity 23 is successively packed in the cavity 23 from a bottom on the side of the gate 28 of the cavity toward a higher part on the side of an air vent 30 thereof. Accordingly, as compared with the case where the cavity 23 is horizontally arranged, a phenomenon that air lighter than the resin 31 is entrapped in the resin 31 is reduced, and air in the cavity 23 is pushed up by the resin 31 and discharged favorably to the external, side through the air vent 30. As a result, air in the cavity 23 is completely discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding technique, and more particularly to a technique for preventing the generation of voids in a molded product. And about the valid ones.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, as a transfer molding apparatus for molding a resin-sealed package of a semiconductor device, a lead frame is placed between a top mold and a bottom mold of a mold so that pellets can be set in a cavity. There is a structure in which a package (hereinafter, referred to as a resin) as a molding material is injected from a gate opened at an end portion of one side wall of the cavity to mold the package.

Incidentally, examples of the transfer molding technique are described in JP-A-56-108236, JP-A-57-35576, JP-A-61-292330 and JP-A-57-123222. Gazette and the Industrial Research Institute Co., Ltd. "Electronic Materials November 1981 Separate Volume"
There are P170 to P175 issued on November 10, 1981.

[0004]

In such a transfer molding apparatus, the cavities are arranged horizontally, and the resin injected from the gate into the cavities is sequentially moved into the cavities from the end on the gate side. Go filled. At this time, the air existing in the cavity is pushed by the resin injected into the cavity, and is then exposed to the outside of the cavity through the air vents provided at the end of the side wall opposite to the gate side of the cavity. Exhausted. The resin is filled into the cavity by exhausting the cavity.

However, when the cavity is filled with the resin in this way, since the cavity is arranged horizontally, the resin injected into the cavity is entrained with the air in the cavity, The present inventor has revealed that there is a problem that voids (air bubbles) are formed in the resin-sealed package after molding.

An object of the present invention is to provide a molding apparatus capable of preventing the occurrence of voids in a resin molded product.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0008]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, the molding material is filled in the cavity formed on the mating surface of the upper mold and the lower mold through the gate opened at the end of the cavity, and the air in the cavity is filled with air. In a molding method in which a molded product is molded by the cavity by being discharged from the cavity along with the filling, the cavity is tilted with respect to a horizontal plane when the molding material is filled in the cavity. The gate is opened at the lower end of the cavity, and the air vent for discharging the air in the cavity is opened at the higher end of the cavity. To do.

[0010]

According to the above-mentioned means, the resin injected into the cavity from the gate opened at the lower side of the cavity is sequentially moved from the bottom on the gate side to the higher portion on the air vent side in the cavity. Go filled. Therefore, compared to the conventional case where the cavity is arranged horizontally, the phenomenon that air lighter than the resin is caught in the resin is reduced, and the air in the cavity is pushed by the resin and passes through the air vent. Good exhaust to the outside of the cavity. Since the air in the cavity is completely discharged, no void is formed inside the molded product molded by the cavity.

[0011]

1 is a partially omitted front sectional view showing a transfer molding apparatus according to an embodiment of the present invention, and FIG. 2 is a partially omitted exploded perspective view showing the transfer molding apparatus. Figure 3
(A), (b) is a top view and b- which show a resin-sealed object.
It is sectional drawing which follows the b line. 4 (a) and 4 (b) are a partially omitted plan view and a cross-sectional view taken along line bb showing after resin sealing.

In this embodiment, the molding apparatus according to the present invention is a multi-molding apparatus for molding a resin-sealed package of a semiconductor integrated circuit device (hereinafter referred to as DIP / IC) having a resin-sealed dual in-line package. It is configured as a pot type transfer molding device.

In the present embodiment, the resin-sealed object 14 as a work of this transfer molding apparatus is as shown in FIG.
It is configured as shown in (a) and (b),
The resin-sealed object 14 includes the multiple lead frame 1.

The multiple lead frame 1 is a thin plate made of a copper-based (copper or its alloy) material, and is integrally formed by an appropriate means such as punching press working or etching working. This multiple lead frame 1
A plurality of unit lead frames 2 are arranged side by side in a row in the horizontal direction. However, only one unit is shown in the drawing.

The unit lead frame 2 has a pair of outer frames 3 each having a positioning hole 3a. Both outer frames 3 are arranged in parallel at a predetermined interval so that the multiple lead frame 1 is continuous. It is extended in a series in the direction to do. A pair of section frames 4 are arranged between the outer frames 3 and 3 in parallel with each other between the unit lead frames 2 and 2 adjacent to each other, and are integrally constructed. The unit lead frame 2 is formed in a rectangular frame body.

In each of the unit lead frames 2, tab suspension leads 7, 7 are arranged at right angles to both outer frames 3 and 3 and are integrally projected, and the tips of the tab suspension leads 7, 7 are provided. A tab 8 formed in a substantially square flat plate shape is arranged between the outer frames 3 and 3 and the section frames 4 and 4 so as to be substantially concentric with the frame and is integrally suspended. The tab 8 is lowered toward the back surface by the thickness of the semiconductor pellet (described later) from the surface of the lead 9 group described later (so-called tab lowering).

A pair of dam members 5 are arranged between the outer frames 3 and 3 so as to extend at right angles on both sides of the tab suspension lead 7 and are integrally erected.
A plurality of leads 9 are arranged at equal intervals in the longitudinal direction on both dam members 5 and 5, and are integrally projected so as to be parallel to each other and orthogonal to the dam member 5.

The inner ends of the leads 9 are arranged so that the ends thereof are close to the tabs 8 and surround the tabs 8 so that the inner parts 9 are located inside the resin-sealed package described later.
a respectively. On the other hand, the outer extension of each lead 9 has its tip mechanically connected to the section frame 4 and constitutes an outer portion 9b located outside the resin-sealed package described later.

The portion between the adjacent leads 9 of the dam member 5 substantially constitutes a dam 6 for stopping the flow of the resin at the time of molding a package which will be described later.

The multiple lead frame 1 constructed as described above is subjected to pellet bonding work for each unit lead frame 2 and then wire bonding work (not shown). , Fig. 3
As a result, the assembly as the resin-sealed object 14 which is the work as shown in (a) and (b) is manufactured.
These bonding operations are sequentially carried out for each unit lead frame 2 by pitch-feeding the multiple lead frames 1 in the lateral direction.

First, by pellet bonding work,
In a so-called pre-process in the manufacturing process of a semiconductor device, a pellet 12 as a semiconductor integrated circuit structure in which a bipolar type integrated circuit element (not shown) is formed is formed in a substantially central portion on a tab 8 in each unit lead frame 2. And is fixed via a bonding layer 11 formed of a suitable material such as silver paste.

The silver paste is formed by mixing an epoxy resin adhesive, a curing accelerator, and a solvent with silver powder. After the silver paste applied on the lead frame is pressed with pellets, The bonding layer 11 is formed by being cured at an appropriate temperature.

Between the bonding pad 12a of the pellet 12 fixedly bonded to the tab 8 and the inner portion 9a of each lead 9 in the unit lead frame 2, a copper-based, gold-based or aluminum-based material is used. The wire 13 formed and used is bridged by bonding both ends thereof by using an appropriate wire bonding device (not shown) such as an ultrasonic pressure bonding type. As a result, the integrated circuit built in the pellet 12 has bonding pads 12a,
The wire 13, the inner portion 9a of the lead 9, and the outer portion 9b electrically lead to the outside.

In the multiple lead frame as the work, which is the resin-sealed object 14 pelletized and wire-bonded in this manner, a package group for resin-sealing each unit lead frame is as follows. Simultaneous molding is performed on a unit lead frame group using the configured transfer molding apparatus.

The transfer molding apparatus 20 according to this embodiment.
Includes a pair of an upper mold 21 and a lower mold 22, which are clamped to each other by a cylinder device or the like (not shown). A plurality of sets of upper mold cavity recesses 23a and lower mold cavity recesses 23b are formed on a mating surface of the upper mold 21 and the lower mold 22, and a pair of members cooperate with each other to form one cavity 23. It is buried in.

When the resin-sealed object 14 as the work having the above-mentioned structure is used to transfer-mold a resin-sealed package, each cavity 23 in the upper die 21 and the lower die 22 has a multiple lead frame 1. Are arranged so as to correspond to the spaces between the pair of dam members 5 and 5 in each unit lead frame 2.

The mating surfaces of the upper mold 21 and the lower mold 22 each form a V-shaped slanted surface composed of a pair of slanted surfaces that are slanted with respect to the horizontal plane, and the left and right slanted surfaces have a plurality of cavities 23. The sets are arranged symmetrically.

Since the upper mold 21 and the lower mold 22 are formed symmetrically, the right mold is representatively shown in FIG. 1, and the reference numeral is used on one side for the description.
Upper mold cavity recess 23a and lower mold cavity recess 2
Each of the cavities 3b has a bottom surface arranged in parallel to an inclined surface which is a mating surface, and each cavity 23 inclines upward from the bending position side at the center of the V-shaped mating surface toward the left and right end portions. Is provided.

A plurality of pots 24 are arranged in the center of the V-shaped mating surface of the upper mold 21 and are arranged vertically corresponding to the respective cavities 23. Each pot 24 has a vertical opening. A plunger 25 that is vertically advanced and retracted by a cylinder device (not shown) crushes a tablet as a molding material, and a liquid resin (hereinafter, referred to as a resin) obtained by melting the tablet can be fed. Each is inserted.

A plurality of culls 26 are provided at the central bent position of the V-shaped mating surface of the lower mold 22, and are vertically arranged so as to be opposed to the pots 24. Two main runners 27 are connected to each cull 26,
Both main runners 27, 27 are arranged so as to face each other. Further, each main runner 27 is arranged so that the bottom surface thereof is parallel to the mating surface of the lower mold 22, and is buried.

Further, the culls 26, 26 are connected to each other by respective sub-runners 27A which are recessed on the central bending line of the V-shaped mating surface of the lower die 22.

The other end of each main runner 27 is connected to a gate 28 which is recessed in the mating surface of the lower die 22. The bottom surface of the gate 28 is formed such that the depth thereof gradually decreases from the main runner 27 side toward the cavity 23 side, and the lower cavity recess 23b is formed.
Is arranged so as to open at the end on the low position side with respect to gravity.

The relief recess 2 is formed on the mating surface of the lower mold 22.
In order that the lead frame 9 can escape the thickness of the lead frame, it is a rectangle slightly larger than the outer shape of the multiple lead frame 1, and is recessed at a constant depth of a dimension substantially equal to the thickness.

A cavity 23 is formed on the mating surface of the upper mold 21.
An air vent 30 that constitutes an air vent passage for discharging the air in the inside is disposed so as to open at the end of the upper cavity recess 23a on the high position side against gravity, and is submerged. The end is opened to the side surface of the upper mold 21.

An upper heat block (not shown) and a lower heat block (not shown) are provided outside the upper mold 21 and the lower mold 22, respectively, and electric heaters (see FIG. (Not shown) is laid so as to heat the pot, cull, runner and resin in the cavity in the upper mold 21 and the lower mold 22. By this heating, the tablets are melted, and the resin formed by melting the tablets is reduced to a predetermined viscosity.

In the transfer molding method in which the transfer molding apparatus 20 is used, a tablet made of epoxy resin or the like (hereinafter referred to as resin) as a molding material is used. This tablet is formed by compacting a powdery resin into a cylindrical shape, and is formed to have an outer diameter slightly smaller than the inner diameter of the pot 24 of the transfer molding apparatus 20, and is put into the pot 24 and melted by heating. Is configured to.

Next, the transfer molding method according to the embodiment of the present invention will be described by explaining the operation of the transfer molding apparatus having the above-described structure.

At the time of transfer molding, the resin-sealed object 14 having the above-described structure, which is a work, has the multiple lead frames 1 in the escape recesses 29 in which the lower die 22 is recessed. The pellets 12 of No. 2 are arranged and set so as to be housed in the respective cavities 23.

Subsequently, the upper die 21 and the lower die 22 are clamped, and tablets (not shown) are placed in the pots 24.
Are input respectively. The tablet placed in the pot 24 is crushed by the plunger 25. In addition, after being placed in the pot 24, the upper mold 21 and the lower mold 2
The tablets are melted and liquefied because they are heated by the upper and lower heat blocks which are respectively arranged outside of 2.

Then, the tablet is crushed, and
The heated and liquefied resin 31 is sent to each cavity 23 through each runner 27 and gate 28 by the pushing force of the plunger 25 from the cull 26 which is submerged facing the pot 24, and is filled therein. I will go.

At this time, the resin injected into the cavity 23 from the gate 28 arranged on the lower side of the cavity 23 is moved from the lower portion on the gate 28 side to the higher portion on the air vent 30 side in the cavity 23. Since the resin 31 is sequentially filled, the air entrainment phenomenon by the resin 31 is reduced, and the air in the cavity 23 is pushed by the resin 31 and satisfactorily exhausted from the air vent 30 to the outside of the cavity 23.

After the injection, when the liquid resin 31 is thermoset and the resin-sealed package 15 is molded, the upper mold 21 and the lower mold 22 are opened and the resin is ejected by an ejector pin (not shown). The group of sealed packages 15 is released. The multiple lead frame 1 as a work in which the group of resin-sealed packages 15 is formed in this manner is removed from the transfer molding apparatus 20 by a handler (not shown).

Inside the package 15 thus resin-molded, as shown in FIG.
The tab 8, the pellet 12, the inner portion 9a of the lead 9 and the wire 13 are resin-sealed. As described above, since the air is completely discharged from the inside of the cavity 23 when the resin 31 is filled in the cavity 23, no void is formed inside the resin-sealed package 15.

In the transfer molded body molded by using the transfer molding device 20, the runner portion is separated from the multiple lead frame in which the resin-sealed package is molded by the molded product separating device (not shown).

The multiple lead frame 1 whose runner portion is separated by the molded product separating device is then cut off the outer frame 3, the section frame 4 and the dam 6 in the lead cutting molding step, and the outer portion of each lead 9 is cut off. 9b is bent downward. The DIP IC is manufactured by the above manufacturing process.

In the DIP / IC thus manufactured, the outer portions 9b of the leads are inserted into the through holes of the printed wiring board, and are electrically and mechanically connected by the solder fillets.

According to the above-mentioned embodiment, the following effects can be obtained. The cavity 23 is arranged to be inclined with respect to the horizontal plane, the gate 28 is opened at the end of the cavity 23 on the low position side against gravity, and the cavity 28 is formed on the end on the high position side against gravity. Since the air vent 30 for exhausting the air in the cavity 23 is opened, the resin 31 injected into the cavity 23 through the gate 28 moves through the cavity 28 into the gate 28.
The air from the lower side on the side of the air vent 30 is filled in order to the higher side on the side of the air vent 30, so that the air lighter than the resin 31 is pushed out by the resin 31 and the air vent 30 moves to the cavity 2.
3 can be satisfactorily exhausted to the outside, and the phenomenon that air is caught in the resin 31 can be reduced.

As described above, the air in the cavity 23 is completely discharged from the cavity 23.
It is possible to prevent generation of voids in the resin-sealed package 15 after molding.

5A and 5B are views showing a transfer molding apparatus according to another embodiment of the present invention. FIG. 5A is a front sectional view showing a state before resin injection, and FIG. 5B shows a state at the time of resin injection. It is a front sectional view.

The transfer molding apparatus 40 of the second embodiment is different from the first embodiment in that the group of cavities 43 is arranged in one row in the upper die 41 and the lower die 42, and
Normally, it is formed to be horizontal, and the upper mold 41 and the lower mold 42 are configured to be tiltable with respect to the horizontal plane. By the way, pot 44, plunger 45,
The culls 46 and the lead frame relief recesses 49 are formed vertically, and are therefore arranged at right angles to the upper mold 41, the lower mold 42 and the cavities 43, and are arranged only on one side of the cavity 43 group. It is set up.

Transfer molding apparatus 4 according to the second embodiment
In the case where the transfer molding method according to one embodiment of the present invention is carried out according to No. 0,
As shown in FIG. 5B, the upper mold 41 and the lower mold 42 are connected to the pot 44 as a whole, and the runner 47 and the gate 48 are on the lower side against gravity, and the air vent 50 is on the upper side. Is rotated and tilted. Then, the resin 31 is poured into the cavity 43 from the pot 44.

At this time, since the upper mold 41 and the lower mold 42 are entirely rotated and tilted, the gate 48 is located on the lower side of the cavity 43 with respect to gravity, and the air vent 50 is located in the cavity 43. Since they are arranged on the high position side with respect to gravity, respectively, as in the case of the first embodiment, the cavity 4 is filled with the resin 31.
The air in 3 is pushed out very effectively from the air vent 50. Therefore, as in the first embodiment, it is possible to prevent the occurrence of voids inside the resin-molded resin-sealed package.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

The specific shapes and structures of the upper and lower molds, pots, plungers, runners, gates, cavities, and other constituent elements are not limited to the above-mentioned configurations, but it is desirable to appropriately select them according to molding conditions and the like.

In the above description, the invention mainly made by the present inventor is the field of application which is the background of the invention.
The case where the present invention is applied to a transfer molding apparatus used for molding a resin-sealed package of an IC has been described, but it is applied to all molding apparatuses such as a molding apparatus used for a resin-sealed package of other electronic parts. be able to.

[0056]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

The cavity is arranged so as to be inclined with respect to the horizontal plane, and a gate is opened at the lower end of this cavity, and the air inside the cavity is provided at the higher end. By opening the air vent for discharging, the resin is filled from the lower part on the gate side to the higher part on the air vent side in the cavity in order, so the air in the cavity is very effective through the air vent by the resin. It will be exhausted. As a result, it is possible to prevent the occurrence of voids in the resin molded product after molding.

[Brief description of drawings]

FIG. 1 is a partially omitted front sectional view showing a transfer molding apparatus according to an embodiment of the present invention.

FIG. 2 is a partially omitted exploded view showing the transfer molding apparatus.

FIG. 3 is a plan view showing a resin-sealed object and a sectional view taken along line bb.

FIG. 4 is a partially omitted plan view partially cut and a cross-sectional view taken along line bb showing after resin sealing.

5A and 5B are views showing a transfer molding apparatus according to another embodiment of the present invention, in which FIG. 5A is a front sectional view showing a state before resin injection, and FIG. 5B is a front sectional view showing a state during resin injection. It is a figure.

[Explanation of symbols]

1 ... Multiple lead frame, 2 ... Unit lead frame, 3
... outer frame, 4 ... section frame, 5 ... dam member, 6 ... dam,
7 ... Tab suspension lead, 8 ... Tab, 9 ... Lead, 9a ... Inner portion, 9b ... Outer portion, 11 ... Bonding layer, 12
... Pellet, 13 ... Wire, 14 ... Resin-sealed object (work), 15 ... Resin-sealed package, 20 ... Transfer molding device, 21 ... Upper mold, 22 ... Lower mold, 23 ... Cavity, 23a ... Upper cavity Tee recess, 23b ... Lower cavity recess, 24 ... Pot, 25 ... Plunger, 26
… Cal, 27… Main runner, 27A… Sub runner, 2
8 ... Gate, 29 ... Lead frame escape recess, 30 ... Air vent, 31 ... Liquefied resin (molding material), 40 ... Transfer molding device, 41 ... Upper mold, 42 ... Lower mold, 43 ...
Cavity, 44 ... Pot, 45 ... Plunger, 46
... Cull, 47 ... Main runner, 48 ... Gate, 49 ... Lead frame escape recess, 50 ... Air vent.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // B29L 31:34

Claims (3)

[Claims] 1. A molding material is filled in a cavity formed on a mating surface of an upper mold and a lower mold through a gate opened at an end of the cavity, and air in the cavity is filled with air. In a molding method in which a molded product is molded by the cavity by being discharged from the cavity during filling, the cavity is tilted with respect to a horizontal plane when the molding material is filled in the cavity. The gate is opened at the lower end of the cavity, and the air vent for discharging the air in the cavity is opened at the higher end of the cavity. Molding method. 2. A cavity is formed on a mating surface between the upper mold and the lower mold, and the molding material is filled in the cavity through a gate opened at an end of the cavity, and at the same time, the inside of the cavity is filled with the molding material. In a molding apparatus configured so that air is discharged from the inside of the cavity as it is filled, the cavity is arranged so as to be inclined with respect to a horizontal plane, and the cavity is arranged at an end portion on the low position side. The molding apparatus is characterized in that a gate is opened and an air vent for discharging the air in the cavity is opened at the end on the high position side. 3. A cavity is formed on a mating surface between the upper mold and the lower mold, and the molding material is filled into the cavity through a gate opened at an end of the cavity, and at the same time, the inside of the cavity is filled with the molding material. In a molding apparatus configured so that air is discharged from the cavity as it is filled, the upper mold and the lower mold are configured to be tiltable with respect to a horizontal plane, At the time of filling, the upper mold and the lower mold are tilted so that the gate is on the lower side of the cavity and the air vent opened in the cavity is on the higher side of the cavity. A molding apparatus characterized by being configured as follows.