JPH0897344A - Electronic component package - Google Patents

Abstract

PURPOSE: To provide an electronic component package which has excellent reliability in connection with no voids without providing unnecessary protruding parts. CONSTITUTION: A wiring board 1 is provided by forming a conductor circuit 11 on the surface, and by forming an electronic component mounting part on the circuit. An electronic component package is provided with the wiring board 1, an electronic component mounted on the electronic component mounting part, a lead frame 4 which has a plurality of leads electrically !connected with the conductor circuit 11, and mold resin in which the wiring board 1, the electronic component and the part of the lead frame 4 are encapsulated. At the time of resin-encapsulation, a flat plate integrated with the lead frame is arranged at the corner positioned in the vicinity of an air vent arranged on the diagonal line from the injection gate of molding dies 81 and 82.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component package, and more particularly to an electronic component package which is composed of a lead frame and a wiring board, has a simple structure, and is free from voids in a resin sealing portion.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and higher performance of electronic equipment, electronic component packages for mounting electronic components such as semiconductor chips have also been increased in pin count, miniaturization and surface mounting. Here, as the electronic component package for surface mounting, there are generally those manufactured by using a so-called lead frame such as QFP (quad flat package) and PLCC (plastic leaded chip carrier). In these electronic component packages,
The number of pins of semiconductor chips mounted, miniaturization and high density, and further high frequency driving are progressing, and accordingly, electronic component packages are also required to have a narrower inner lead pitch, improved heat dissipation and electrical characteristics. There is. As one method of satisfying these requirements, an electronic component package using a lead frame and a wiring board is generally well known.

Conventionally, in this type of electronic component package, as shown in FIG. 5, a lead frame 4 used.
Has one end connected to the upper surface of the wiring board. Therefore,
In the manufacturing of electronic component packages, when transfer molding is performed, the mold resin injected into the cavity of the mold from the runner 821 provided in the lower mold 82 at the time of molding has a lower flow rate in the upper flow path Fa. It is easier to flow than the road Fb. Therefore, before the air in the lower flow passage Fb is completely exhausted from the air vent 6, the mold resin in the upper flow passage Fa sneaks into the lower flow passage Fb, and voids 10 are likely to occur in a part of the lower flow passage Fb. In particular, when the heat dissipation member is adhesively fixed to the lower surface of the wiring board, the void 10 is more likely to occur. In order to solve the above problems, as shown in FIG. 6, a method of providing a convex portion 9 on the front surface side of the wiring board so as to eliminate the difference in the inflow velocity of the mold resin between the upper and lower sides of the mold during molding is proposed. Known (Japanese Patent Laid-Open No. 4-21546)
No. 1).

[0004]

However, in the electronic component package, since the convex portion 9 is newly provided, the structure becomes complicated and the productivity becomes poor and the cost becomes high. Further, since the convex portion 9 is provided in this portion after the wiring board is joined to the lead frame, stress is applied to the joint portion (electrical connection portion) in the step of providing the convex portion 9, and the connection reliability is improved. Is reduced. To prevent the occurrence of voids when the heat dissipation member is attached to the lower surface of the wiring board (particularly when one surface of the heat dissipation member is exposed from the surface of the electronic component package to obtain high heat dissipation) In order to eliminate the difference in the inflow velocity of the mold resin between the upper and lower sides of the mold, it is necessary to make the projection 9 large (high and wide). Therefore, in this case, the package surface and the convex portion 9
The distance from the top surface becomes shorter, and package cracks are more likely to occur during mounting (during reflow heating) due to moisture absorption. In addition, the thickness of the package must be increased in order to ensure this reliability, and the demand for miniaturization cannot be satisfied.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic component package which is excellent in connection reliability and does not generate voids without providing an extra convex portion. .

[0006]

The inventor of the present invention has made an earnest study on an electronic component package which is excellent in connection reliability without forming an extra convex portion and has no void. The present invention has been completed by discovering that the resin that has passed through the air vents at the corners on a diagonal line is blocked by the upper surface to generate voids.

That is, in the electronic component package of the first aspect of the present invention, a wiring board having a conductor circuit formed on the surface thereof and further having an electronic component mounting portion formed thereon, and the electronic circuit mounted on the electronic component mounting portion and electrically connected to the conductor circuit. Electrically connected one or more electronic parts, a lead frame having a plurality of leads electrically connected to the conductor circuit, the wiring board, the electronic parts, and a part of the lead frame. In the electronic component package consisting of the mold resin part
At the time of molding resin sealing, by arranging a flat plate portion integrated with the lead frame at a corner portion located at least in the vicinity of the air vent of the molding die arranged diagonally with the resin injection gate, the lead is formed. It is integrated with the frame, and it is characterized by no visible voids.

The second aspect of the present invention is characterized in that a heat dissipation member is adhesively arranged below the electronic component and below the wiring board.

[0009]

EXAMPLES The present invention will be specifically described below with reference to examples. As shown in FIG. 1, the electronic component mounting substrate 101 that constitutes the electronic component package 102 of the first embodiment is configured by mounting the electronic component 2 on the electronic component mounting substrate 101 and resin-sealing by transfer molding. (Fig. 5). The entire shape and size of the mold part of the electronic component package 102 is 28.0 mm × 28.0 mm × 3.
It has a flat plate shape of 2 (thickness) mm (a plurality of outer leads project outward from the side surface). As shown in FIG. 1, the electronic component mounting board 101 includes a wiring board 1 and a lead frame 4 having a plurality of leads.

The wiring board 1 is made of glass cloth / epoxy resin and has a size of 25.0 mm × 25.0 mm ×.
It is 0.4 (thickness) mm. Instead of glass cloth / epoxy resin, a base material made of glass cloth and a heat-resistant resin such as bismaleimide / triazine resin or polyimide resin may be used. Then, a predetermined conductor circuit (made of copper foil) 11, an electronic component mounting portion 13, and a through hole are formed on this surface by an ordinary printed wiring board manufacturing method (for example, a subtractive method). Has a plated layer of nickel / gold or the like. Furthermore, although a solder resist layer is formed on a part of the conductor circuit 11 (not shown), it is not always necessary.

The lead frame 4 has a plurality of leads, and these leads are provided on the outer peripheral portion of the wiring board 1.
The leads are bonded and fixed using an adhesive, and the inner ends of the leads are connected by solder through the through holes. The plurality of leads are composed of inner lead portions located inside the resin encapsulation portion and outer lead portions located outside the resin encapsulation portion.
The book extends in all directions of the wiring board 1. The number of leads is not limited in the present invention. For example, a multi-pin electronic component package 1 such as 208 or 304
In No. 02, the structure of the present invention is particularly effective, but in this embodiment, there are 36 in order to make the drawings easy to see. Further, in this embodiment, the inner lead extends straight from the outer lead to the solder connection portion of the wiring board 1, but the inner lead may be bent as shown in FIG. 3, for example. Whether or not the inner lead is bent and the shape thereof are determined by the position of each outer lead and the corresponding position of the solder connection portion on the surface of the wiring board 1.

The electronic component mounting board 1 of the first embodiment
01, as shown in FIG. 2 which is a partially enlarged view of FIG.
A flat plate portion 5 integrated with the lead frame 4 is formed.
The flat plate portion 5 is integrally formed when the lead frame 4 is manufactured by a usual method such as etching or stamping. The inner end portion of the flat plate portion 5 is adhered to the corner portion of the substrate. Bonding is easy because each lead can be bonded simultaneously when it is bonded to the substrate. Further, it does not necessarily have to be adhered to the substrate. Since the flat plate portion 5 is integrated with the lead frame 4 at the time of molding, it has a strength to sufficiently dam the resin on the upper surface. It is preferable that the flat plate portion 5 has such a shape that the gap between the inner leads adjacent to each other is as small as possible. (FIGS. 2 and 3) And, depending on the thickness of the lead frame 4, in the case of 0.15 mm,
A gap of 0.15 to 0.20 mm is good. This is because the narrower the gap, the greater the effect of blocking the molding resin on the upper surface of the substrate during molding.

The electronic component mounting portion 13 provided on the electronic component mounting substrate 101 has an electronic component (size: 11.
A semiconductor chip (0 mm × 11.0 mm × 0.4 (thickness) mm) 2 is bonded and fixed by an adhesive layer. The electronic component 2 is connected to the conductor circuit 11 by the bonding wire 3. (Not shown) Then, as shown in FIG. 4, set in the transfer mold dies 81 and 82,
Mold resin is injected. At this time, no void was observed due to the flat plate portion 5 arranged in the vicinity of the air vent portion diagonally opposite to the gate portion of the molding die. After that, through appropriate steps, an electronic component package 102 without voids as shown in FIG. 5 was obtained.

Next, FIG. 6 is a partial cross-sectional view of an electronic component mounting substrate 101 set in a mold for obtaining an electronic component package 102 according to another embodiment of the present invention. This electronic component package 102 includes a wiring board 1
As the material, various resins and ceramics such as silicon, polyimide, alumina, epoxy, and glass epoxy are used, and a single layer or a plurality of layers may be laminated. A conductor circuit 11 is formed on the surface of the wiring board 1, and the conductor circuit 11 and each lead are electrically connected by a through hole. (Not shown) Further, a central portion of the wiring board 1 is penetrated, and a heat dissipation plate for heat dissipation is joined to the lower portion by an adhesive. Also, on the heat sink,
The electronic component 2 is mounted and connected to the conductor circuit 11 by the bonding wire 3. The electronic component package 102 is provided with the flat plate portion 5, and the first embodiment
Is the same as. When the heat sink is fixed to the lower surface of the wiring board 1, the difference in the mold resin flow rates between the upper and lower surfaces of the wiring board 1 during transfer molding becomes large, and voids are more likely to occur. ,
No void was observed.

The present invention is not limited to the specific examples described above, and various modifications may be made within the scope of the present invention depending on the purpose and application. That is,
The flat plate part integrated with the lead frame is not limited to the case where it is arranged only at the corner part which is located in the vicinity of the air vent which is diagonally arranged with the gate part of the molding die, and it is arranged near the other two corners of the air vent. It doesn't matter.
Further, it is preferable that the shape of the flat plate portion is such that the gap between the flat portion and the adjacent inner lead is as narrow as possible, but the shape may be such that the gap becomes large within a range where voids do not occur. The gaps as shown in the embodiment do not have to be equal. Further, the shape of the inner end portion of the flat plate portion is not limited at all. Further, the flat plate portion can be integrated with the adjacent leads to be used as an electric circuit.

[0016]

[Operation and effect] The mold resin injected from the gate is divided into the upper and lower surfaces of the substrate and advances in the mold cavity. At this time, the mold resin on the upper surface side of the substrate quickly reaches the air vent portion diagonally opposite to the gate portion due to the difference in the flow velocities of the resin on the upper and lower surfaces. If the flat plate portion 5 of the present invention is provided in the vicinity of the air vent, the resin that has reached the upper surface is less likely to go around to the lower surface, and the air vent 6 of the lower mold is
The air on the lower surface escapes from the air vent 6 by the time the resin on the lower surface reaches the air vent 6, and voids do not occur. As described in detail above, according to the present invention,
It has excellent connection reliability without the need for extra protrusions.
It is possible to provide an electronic component package that does not generate voids at low cost and with high productivity.

[Brief description of drawings]

FIG. 1 is a plan view of an electronic component package according to a first embodiment.

FIG. 2 is a partially enlarged plan view in which a flat plate portion is provided in the electronic component package according to the first embodiment.

FIG. 3 is a partially enlarged plan view in which a flat plate portion having another shape is provided in the electronic component package according to the first embodiment.

4 is a partial cross-sectional view of the electronic component package of FIG. 2 according to the present invention.

FIG. 5 is a cross-sectional view of a void-free electronic component package according to the present invention.

FIG. 6 is a partial cross-sectional view of an electronic component package showing another embodiment according to the present invention.

FIG. 7 is an explanatory diagram showing a state in which a sealing resin is being flown into a predetermined cavity in an attempt to manufacture a conventional electronic component package.

FIG. 8 is an explanatory diagram showing a state in which a sealing resin is flowing into a predetermined cavity in an attempt to manufacture a conventional void-free electronic component package.

[Explanation of symbols]

1; wiring board, 2; electronic component, 3; bonding wire, 4; lead frame, 5; flat plate part, 6; air vent, 9; convex part, 10; void, 11; conductor circuit, 13;
Electronic component mounting portion, 821; Runners, 81, 82; Mold, 101; Electronic component mounting substrate, 102; Electronic component package

Claims (2)

[Claims] 1. A wiring board having a conductor circuit formed on at least a surface thereof and further having an electronic component mounting portion formed thereon, and one or a plurality of wiring boards mounted on the electronic component mounting portion and electrically connected to the conductor circuit. An electronic component, and a lead frame having a plurality of leads electrically connected to the conductor circuit,
In an electronic component package including the wiring board, the electronic component, and a mold resin portion for sealing a part of the lead frame, at least a resin injection gate and a mold disposed diagonally at the time of molding resin sealing. An electronic component package characterized in that no void is visually observed by disposing a flat plate portion integrated with the lead frame at a corner portion located near the air vent of the mold. 2. The electronic component package according to claim 1, wherein a heat radiation member is adhesively arranged below the electronic component and below the wiring board.