JP2920447B2 - IC chip packaging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of packaging an IC chip, such as a SIP, DIP or flat pack type, in which an IC chip having a 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 type of ceramic, metal, and glass is not only expensive but also thin because it must form a shell inside which an IC chip can be mounted, or sandwich it in a sandwich in a plate-shaped package to seal the surroundings. This is disadvantageous for packaging. That point I
The plastic type, in which the C chip is molded integrally with a thermoplastic resin, is not only inexpensive in material, but also enables automation of bonding using a continuous lead frame, and enables mass badge processing in the molding process. Therefore, an inexpensive package can be obtained, and it is easy to form a thin package.

[0003]

In resin molding an IC chip, the IC chip must be protected from resin pressure. The IC chip is usually located at the center of the package, but the molten resin flows in that part,
In addition, there is a concern that the extra fine wire and the IC chip itself may be damaged due to the step-up. Therefore, if the injection pressure of the resin is increased, the IC chip may be damaged. On the other hand, if the injection pressure is lowered, the filling failure may occur, resulting in a decrease in the reliability of the package. If the molten resin is made to have good fluidity by a runnerless method in which a heating means is provided at the injection port, the injection pressure can be somewhat reduced, but there is a concern about insufficient filling at the end.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for packaging an IC chip in which the influence of the resin pressure applied to the IC chip is reduced. Then, in a package-shaped cavity in which a feeder is provided on a peripheral portion on a surface opposite to the injection port,
With the lead frame parallel to the surface, the IC chip is placed on the opposite side of the injection port, and on the side opposite to the injection port of the lead frame, the periphery of the IC chip is covered with a partition together with the wire bonding portion. The molten resin is injected from the injection port, and when the molten resin has substantially spread into the cavity and is also filled in the feeder, the injection port is closed, and then the molten resin in the feeder is pushed back into the cavity, and at the same time, The partition is moved out of the cavity.

[0005]

The molten resin injected into the cavity spreads radially at the upper part of the lead frame, passes through the gap of the lead frame, flows into the lower side, and spreads throughout the cavity. At this time, the periphery of the IC chip is surrounded by partition walls, and the flow of the resin to be filled in other parts via the vicinity of the IC chip is hindered. Since the resin pressure does not increase so much until the resin is completely filled in the cavity, IC
Even when the chip is located at a position close to the injection port, the effect of the resin pressure is small, and the stability is also good because the lead frame is supported by the partition walls. When the molten resin in the feeder is returned and the molten resin in the feeder is returned, the partition is retreated at the same time, so that the space created by the departure is filled with resin by the pressure from the feeder side, and the resin pressure in the cavity is reduced. Rise. By appropriately setting the position of the feeder, the filling density at the end portion away from the injection port is effectively increased, and resin flow or an excessive pressure increase that may damage the IC chip or the like near the IC chip is caused. Is 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 for forming a package-shaped cavity 1, which is composed of an upper mold 2a and a 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, and the injection port 3 employs a runnerless method having a hot runner valve 3a for opening and closing a gate. Feeders 4.4 are recessed below the lower edge of the cavity 1 of the lower die 2b, and push-up rods 4a. 4a is equipped. Further, at the center of the lower surface of the cavity 1 of the lower die 2b, a cylindrical partition wall 5 is provided so as to be able to protrude and retract to the height of the center of the cavity 1.

Reference numeral 6 denotes a lead frame 7 extending in the radial direction.
And an IC chip which is electrically connected to the lead frame 7 by wires 8.
The C chip 6 is placed on the lower mold 2b with the IC chip 6 on the lower side and the lead frame 7 is parallel to the cavity 1 (FIG. 2). The mold 2 lowers the push-up rod 4 a to secure the volume of the feeder, and raises the partition 5 to the center of the cavity 1, that is, until the upper edge abuts on the lead frame 7. However, the space between the IC chip 6 and the lead frame 7 is kept covered with the partition wall together with the wire bonding portion electrically connected by the wire 8, and the cavity 1 is closed by the lowering of the upper mold 2a. And hot runner valve 3
Is opened, and a molten thermoplastic resin 9 is injected into the cavity 1 (FIG. 3). The hot runner valve 3 is closed when the molten resin has substantially spread into the cavity 1 and the feeder 4.
When the molten resin 9 is injected from the injection port, the IC chip
The molten resin 9 spreads radially in the cavity 1 above the lead frame 7 and also flows down through the gap between the lead frames 7, but the resin pressure does not increase until the resin reaches the entire cavity. Even at a position close to the above, the influence of the resin pressure is small, and the lead frame is supported by the partition walls, so that it is not surrounded.

Subsequently, the lifting rod 4a is raised to push the molten resin 9 in the feeder 4 back into the cavity 1, and at the same time, the partition wall 5 is retreated from the cavity (FIG. 4). As the molten resin 9 in the feeder 4 is pushed back into the cavity 1 as described above, the resin pressure in the cavity 1 is increased, and the filling density particularly at the peripheral portion is increased. However, since the IC chip 6 is covered with the partition wall 5,
The pressure of the melted resin that has been pushed back does not act directly, and the influence of the resin pressure is also small.

As a result, the cavity is completely filled with the resin, and there is no shortage of filling, and the IC chip is reliably protected from the resin pressure.
Although the embodiment has been described with respect to a DIP type IC chip, the present invention can be applied to a SIP type and other types. Also, if the injection port is of a runnerless type having a hot runner valve 3a as in the embodiment, it is advantageous to increase the diameter and to easily control the filling pressure, but the insulated runner type, Alternatively, the method may be changed to an extension nozzle method or a well type method. Further, the structure of the mold, such as the position of the injection port and the riser, can be changed as appropriate.

The present invention relates to a method of packaging an IC chip. However, if the idea of the present invention for protecting a member disposed at the center during molding is further developed, the resin molding method is generally used in a field other than the IC chip. It is expected to be applied to

[0011]

According to the present invention, the effect of the resin pressure acting on the IC chip can be reduced in the process of manufacturing a plastic type IC package, so that the reliability of the product is improved. This is suddenly advantageous for package requirements.

[Brief description of the 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 view of disposing an IC chip in a cavity.

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

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

[Explanation of symbols]

1. cavity, 2 mold, 2a upper mold, 2b
・ Lower mold, 3 ・ ・ Injection port, 3a ・ ・ Valve, 4 ・ ・ Feeder,
4a ···································································································· Molten resin

Continuation of front page (56) References JP-A-6-45383 (JP, A) JP-A-6-37130 (JP, A) JP-A-2-109343 (JP, A) JP-A-60-97817 (JP) , A) JP-A-60-27134 (JP, A) JP-A-55-138845 (JP, A) JP-A-59-224314 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) B29C 45/00-45/84 H01L 21/56

Claims (1)

(57) [Claims] A lead frame is provided in an IC package-shaped cavity having an inlet at substantially the center of one of the front and back surfaces and a feeder provided at a peripheral portion on a surface opposite to the inlet. Parallel, the IC chip is placed on the opposite side of the inlet, and I
With the periphery of the C chip covered with the partition together with the wire bonding portion, first, the molten resin is injected from the injection port, and when the molten resin spreads substantially in the cavity and is also filled in the feeder, the injection port is closed. A method of packaging an IC chip, wherein the molten resin in the feeder is pushed back into the cavity, and at the same time, the partition is removed from the cavity.