JPH08306718A - Packaging method for ic chip - Google Patents

Abstract

PURPOSE: To increase the filling density without causing any damage on an IC chip by arranging an IC chip oppositely to an injection port, injecting a resin while surrounding the IC with a barrier wall, closing the gate when the cavity is fully filled and returning the resin in the riser while simultaneously removing the barrier wall. CONSTITUTION: Push-up pistons 5a, 6a are lowered in order to ensure the capacity of a riser and then pushed up until the upper edge a barrier wall 4 abuts against a lead frame 8 thus sustaining a state where an IC chip 6 is surrounded by the barrier wall 4 and then an upper die 2a is lowered to close a cavity 1. A hot runner valve 3a is then opened in order to inject a resin 10 into the cavity 1 and the valve 3a is closed when the cavity 1 and riser 4 are filled with resin. Subsequently, the push-up pistons 5a, 6a are pushed up in order to push back the resin 10 in the risers 5, 6 into the cavity 1 while removing the barrier wall 4 simultaneously. Since the effect of resin pressure acting on the chip can be suppressed, the resin can be filled uniformly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC chip packaging method such as SIP, DIP or flat pack type, in which an IC chip wire-bonded to a lead frame is resin-molded.

[0002]

2. Description of the Related Art IC chip packages are roughly classified into four types: ceramic, metal, glass and plastic. Each of the ceramic, metal, and glass types is not only expensive, but also thin because it requires the formation of a shell inside which an IC chip can be mounted, and sandwiching in a sandwich with a plate-shaped package to seal the periphery. It is disadvantageous to make a package. That point I
The plastic type in which the C chip is integrally molded with the thermoplastic resin is not only cheap in material, but also can be automated in bonding using a continuous lead frame and can be used for mass badge processing in the molding process. Since an inexpensive package can be obtained and it is easy to form a thin package, it will be inevitable to become the mainstream of IC packages in the future.

[0003]

In resin-molding the IC chip, the IC chip must be protected from the injection pressure of the resin. The IC chip is usually located at the center of the package, but at that position, the molten resin flows, and since pressure rise occurs, there is a concern that the ultrafine wire or the IC chip itself will be damaged. Therefore, if the injection pressure of the resin is increased, the IC chip may be damaged,
On the other hand, if it is lowered, filling failure will occur and the reliability of the package will be reduced. Although it is possible to lower the injection pressure to some extent by making the molten resin have good fluidity by a runnerless system in which a heating means is provided at the pouring port, there is a concern of defective filling at the end.

[0004]

SUMMARY OF THE INVENTION The present invention is a method of packaging an IC chip in which the influence of the resin pressure applied to the IC chip is reduced. Then, a lead frame is provided between the inlet and the feeder in the cavity of the IC package shape in which the feeder is provided at the substantially central portion of the surface facing the inlet or the central portion and the peripheral portion. Arranged so that the IC chip is on the opposite side of the injection port, parallel to either of the front and back surfaces,
In a state where the side of the lead frame opposite to the injection port is covered with a partition wall around the IC chip together with the wire bonding part, first, the molten resin is injected from the injection port, and the molten resin is roughly spread over the entire cavity and pressed. When the molten metal is filled in the hot water, the injection port is closed, the molten resin in the feeder is then pushed back into the cavity, and at the same time, the partition is removed from the cavity. And the feeder is
It is desirable to form part or all of the area covered by the partition wall and the entire area outside the partition wall.

[0005]

The molten resin injected into the cavity spreads in the radial direction at the upper part of the lead frame, passes through the gap of the lead frame, flows into the lower side, and spreads into the cavity. At this time, the IC chip is located on the opposite side of the injection port,
Since the periphery thereof is surrounded by the partition wall, the resin pressure is not directly applied or the resin flows through the vicinity, and the influence of the resin pressure is small until the resin is completely filled in the cavity. Further, since the lead frame is supported by the partition wall, the stability is good. If the partition is moved out at the same time when the molten resin in the feeder is returned and the molten resin in the feeder is returned, the space created by the removal is filled with the resin pushed back from the feeder side and the resin pressure in the cavity is reduced. To rise. Since the riser is formed close to the space generated by the withdrawal of the partition wall, the filling density can be effectively increased without causing a resin flow that damages the IC chip and the like. In particular, it is preferable to form the riser at the central portion and the peripheral portion, so that the push-back pressure of the resin acts evenly on the entire area inside the cavity, and the filling density at the end portion away from the injection port is effectively increased. With I
A resin flow that damages the IC chip and the like in the vicinity of the C chip and an excessive pressure rise are prevented.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An IC chip packaging method according to the present invention will be described with reference to the drawings. FIG. 1 shows a mold 2 that forms a package-shaped cavity 1.
And the lower mold 2b. An injection port 3 is provided at the center of the upper surface of the cavity 1 of the upper mold 2a.
A runner-less system equipped with a hot runner valve 3a that opens and closes the gate is adopted. On the lower surface of the cavity 1 of the lower mold 2b facing the injection port 3, a cylindrical partition wall 4 capable of enclosing an IC chip set at the center of a lead frame, which will be described later, is projected to the height of the central portion of the cavity 1. The risers 5, 6, 6 are provided in the central portion of the lower surface area which is provided so as to be covered by the bulkhead and the entire area outside the bulkhead, and the risers 5, 6, 6 are respectively provided. Inside, there is a push-up piston 5a for reducing the internal volume of the riser,
6a, 6a are equipped.

Reference numeral 7 is a lead frame 8 extending in the radial direction.
Is the above-mentioned IC chip which is set at the center of the lower frame 2b and is electrically connected to the lead frame 8 by the wires 9, 9 ... And the lead frame 8 is arranged so as to be parallel to the upper and lower surfaces of the cavity 1 (FIG. 2). Mold 2 is
The push-up pistons 5a, 6a, 6a are lowered to secure the volume of the riser, and the partition wall 4 is placed at the center of the cavity 1.
That is, the lead frame 8 is supported from below by raising the upper edge until it comes into contact with the lead frame 8, and the periphery of the IC chip 6 is surrounded by the IC chip 6 and lead frame 7.
, And the wire bonding portion electrically connected by the wires 9, 9 ... 8 together with a partition wall, and the cavity 1 is closed by lowering the upper mold 2a.
Then, the hot runner valve 3a is opened to inject the thermoplastic molten resin 10 into the cavity 1 (FIG. 3). The hot runner valve 3a is closed when the molten resin is substantially distributed in the cavity 1 and the feeder 4. In the IC chip, when the molten resin 10 is injected from the injection port 3, the molten resin 10 spreads in the cavity 1 on the upper side of the lead frame 8 in the radial direction, and also flows through the gap of the lead frame 7 to the lower side. However, the resin pressure does not increase until it almost reaches the cavity, and I
The resin pressure does not act directly on the surface on which the C chip is set, and the portion of the lead frame on which the IC chip is set is supported by the partition wall and does not stick.

Subsequently, the lifting pistons 5a, 6a, 6a
To raise the molten resin 10 in the feeders 5, 6 and 6 back into the cavity 1, and at the same time as that, the partition wall 4 is withdrawn from the cavity (FIG. 4). In this way, the molten resin 10 in the feeders 5, 6, 6 is pushed back into the cavity 1, so that the space in which the partition wall 4 has retreated is filled with the resin and the resin pressure in the cavity 1 is made uniform. Not only does it not cause defective filling at the end,
Due to the increase in the packing density in the central portion, the lead frame and the resin are reliably brought into close contact with each other. As a result, the cavity is completely filled with the resin, and the IC chip is not damaged.

Although all the embodiments have been described with respect to the DIP type IC chip, they can be applied to the SIP type and other types. Moreover, if the injection port is a runnerless system equipped with a hot runner valve 3a as illustrated,
It is advantageous to increase the diameter and make it easier to control the filling pressure, but the insulated runner system,
Alternatively, the extension nozzle system or the well type system may be changed. Further, the structure of the mold such as the position of the inlet and the feeder can be changed as appropriate.

The present invention is a method for packaging an IC chip. However, if the idea of the present invention for protecting the member arranged in the central portion during molding is further developed, resin molding methods in general in fields other than IC chips can be obtained. It is expected to be applied to.

[0011]

According to the present invention, in the process of resin-molding an IC chip, the influence of the resin pressure acting on the IC chip can be reduced, and the resin can be uniformly filled in the cavity without excess or deficiency. And the spread of plastic types makes it even easier to meet the demand for thin packages.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a mold used in a method of packaging an IC chip according to the present invention.

FIG. 2 is an explanatory diagram showing the arrangement of IC chips in cavities.

FIG. 3 is a process explanatory diagram of a packaging method.

FIG. 4 is a process explanatory diagram of a packaging method.

[Explanation of symbols]

1 ... Cavity, 2 ... Mold, 2a ... Upper mold, 2b ...
・ Lower mold, 3 ・ ・ Injection port, 3a ・ ・ Hot runner valve, 4 ・ ・ Partition wall, 5,6 ・ ・ Raiser, 5a, 6a ・ ・ Pushing piston, 7 ・ ・ IC chip, 8 ・ ・ Lead frame, 9 ... Wire, 10 ... Molten resin

Claims (2)

[Claims] 1. An IC package shape having an injection port substantially in the center of either of the front and back surfaces, and a riser provided at the substantially central part of the surface facing the injection port, or at the substantially central part and the peripheral part. Between the inlet and the feeder in the cavity of the lead frame, the lead frame is arranged in parallel with either of the front and back surfaces, with the IC chip on the opposite side of the inlet, and opposite the inlet of the lead frame. Side with wire bonder I
In a state where the periphery of the C chip is covered with a partition wall, the molten resin is first injected through the injection port, and when the molten resin is substantially spread throughout the cavity and is also filled in the feeder, the injection port is closed. A method for packaging an IC chip, characterized in that the molten resin in the feeder is pushed back into the cavity, and at the same time, the partition is withdrawn from the cavity. 2. A method of packaging an IC chip in which the feeder is formed on a part or all of an area covered by a partition and the entire area outside the partition.