JP2002110886A - Lead frame for semiconductor device and semiconductor device using the same - Google Patents

Abstract

(57) [Problem] To provide a semiconductor device lead frame in which the back surface of an island portion is completely exposed to the surface of a sealing body even when a high-viscosity sealing resin is used. SOLUTION: An opening 10 through which a sealing resin flows is formed at least at a base end portion on the island portion side of a support bar 12 extending from the island portion 11. Here, in order to more reliably expose the back surface of the island portion to the surface of the sealing body,
The width of the opening 10 is preferably 0.15 mm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device lead frame (hereinafter sometimes simply referred to as "lead frame") and a semiconductor device, and more particularly, to a back surface of an island portion on which a semiconductor element is mounted. The present invention relates to a lead frame used for a package type semiconductor device exposed on the surface of a stationary body and a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, various package-type semiconductor devices have been developed in order to cope with an improvement in the degree of integration and an expansion of fields of use. In this package type semiconductor device, in order to further increase the degree of integration and multifunctionality of the semiconductor element,
How to efficiently dissipate the heat generated by the semiconductor element to the outside has been a new issue. That is, in the package type semiconductor device, the semiconductor element is generally sealed with a sealing resin having a low thermal conductivity such as an epoxy resin, so that the heat generated by the semiconductor element increases with higher integration and multifunctionality. The amount could not be sufficiently dissipated to the outside. Therefore, a form in which the bottom surface of the island portion of the lead frame on which the semiconductor element is mounted is exposed to the surface of the sealing body made of a sealing resin and heat generated by the semiconductor element is directly radiated to the outside through the island portion has been considered. .

A package type semiconductor device in which a bottom surface of an island portion of a lead frame is exposed from a sealing body has been generally manufactured as follows. First, a conductive metal material such as a thin metal plate is punched out by press working to form a lead frame having a desired shape. FIG. 5 is a plan view showing an example of the lead frame. The lead frame 1 includes an island portion 11, a support bar 12 extending from four corners of the island 11, a number of inner leads 13 extending toward the island portion 11, an outer lead 14,
A tie bar 15 is provided between the inner lead 13 and the outer lead 14 to support these lead groups.
After the tip portion of the inner lead 13 is plated with Ag or the like to form the electrode portion 17, the island portion 11 is pushed down by the depth of the lower die in a sealing step described later, so that the lead frame 1 is partially concave. I do. And island part 1
1, the semiconductor element 2 is mounted, and the pad 21 of the semiconductor element 2 is mounted.
And the electrode portion 17 of the inner lead 13 are electrically connected by a thin metal wire (wire) 3. In FIG. 5, for convenience, only the pad 21 and a part of the electrode unit 17 are connected by the wire 3.

Next, the island portion 11 on which the semiconductor element 2 is mounted and the inner lead 13 are sealed with a resin. FIG.
Fig. 1 with the lead frame installed in the cavity
2 is a sectional view taken along line AA of FIG. In FIG. 6A, the bottom surface of the island portion 11 on which the semiconductor element 2 is mounted is placed in the cavity of the upper die 41 and the lower die 42 formed according to the predetermined package shape. Attach the lead frame so that it touches. In FIG. 6B, a sealing resin is injected into the cavity heated to a predetermined temperature from the right side of the drawing (the direction of the arrow in FIG. 5), and the cavity is filled with the sealing resin. The stopping resin is cured. In FIG. 6C, the intermediate body of the manufactured package type semiconductor device is taken out of the cavity, and the tie bar 1 is removed.
At the same time as cutting and removing unnecessary parts such as the support bar 12 protruding from the sealing body 16 and the outer lead 14 outside the sealing body 16 with the inner lead 13 extended, the outer lead 14 is bent into a predetermined shape, and It was a package type semiconductor device.

[0005]

In the process of manufacturing such a package type semiconductor device, when the sealing resin is filled in the cavity, the sealing resin may lift the support bar upward. . FIG. 7 is a schematic diagram showing a flow state when the sealing resin is filled. When the sealing resin 5 having a relatively high viscosity, such as an epoxy resin, is injected into the cavity from the resin injection port 43, the sealing resin 5 reaches the bottom surface of the lower mold 42 along the slope, and further the bottom surface is formed. It flows as if crawling. When the sealing resin 5 comes into contact with the support bar 12, the support bar 12 is pushed upward by the flowing force of the sealing resin 5. Thereby, the island portion 11
Is raised, a gap is formed between the island portion 11 and the bottom surface of the lower mold 42, and the sealing resin 5 penetrates there. As a result, the back surface of the island portion 11 is completely formed on the surface of the molded body. There was a problem that was not exposed.

The present invention has been made in view of such a conventional problem. Even when a high-viscosity sealing resin is used, the back surface of the island portion is completely exposed to the surface of the sealing body. It is an object of the present invention to provide a lead frame for a semiconductor device.

Another object of the present invention is to provide a semiconductor device in which an island portion on which a semiconductor element is mounted is completely exposed to the surface of a sealing body, and heat generated by the semiconductor element is efficiently radiated to the outside. .

[0008]

According to the present invention, in a lead frame for use in a package type semiconductor device in which the back surface of an island portion on which a semiconductor element is mounted is exposed on the surface of a sealing body, a support extending from the island portion is provided. There is provided a lead frame for a semiconductor device, wherein an opening through which a sealing resin flows is formed at least at a base end on the island portion side of the bar.

In order to more reliably expose the back surface of the island portion to the surface of the sealing body, the width and length of the opening are preferably 0.15 mm or more.

According to the present invention, the island portion and the semiconductor element are sealed with a sealing resin using the lead frame according to claim 1 or 2 as a lead frame, and the back surface of the island portion is formed on the surface of the sealing body. A semiconductor device characterized by being exposed is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have conducted intensive studies to prevent the support bar from being pushed up by the sealing resin. As a result, by providing an opening in the support bar, the sealing resin is supported. The present invention has been found to be able to reduce the force itself for pushing up the resin, and at the same time, to promote the flow of the sealing resin onto the island portion, and to allow the sealing resin to act as a weight so that the island portion does not float. Reached.

That is, a major feature of the semiconductor device lead frame of the present invention resides in that an opening through which a sealing resin flows is formed at least at the base end of the support bar on the island side. FIG. 1 is a partial plan view showing one embodiment of the lead frame of the present invention. FIG. 1 is a partial plan view of a planar lead frame before the island portion 11 is pushed down. Of the four support bars 12 extending from the four corners of the island portion 11, the support bar 12 on the injection port side of the sealing resin is provided.
A rectangular opening 10 is formed at the base end on the island portion side. The opening 10 only needs to be formed at least in the support bar on the injection port side of the sealing resin, and may of course be formed in another support bar.

FIG. 2 is a partial cross-sectional view when the island portion 11 of the lead frame is pushed down and mounted in the cavity formed by the upper die 41 and the lower die 42. The sealing resin 5 injected from the resin injection port 43 flows along the slope and the bottom surface of the lower mold 42, reaches the island portion 11, and first contacts the base portion of the support bar 12 of the island portion 11. The sealing resin 5 flows into the island portion 11 through the opening 10 formed at the base of the support bar 12, that is, at the base end of the island portion of the support bar 12. The flowing sealing resin 5 acts as a weight, and suppresses the island portion 11 from floating. At the same time, since the opening 10 is formed in the support bar 12, the pushing force of the sealing resin 5 on the support bar 12 is reduced, and the floating of the island portion 11 is further suppressed.

The opening 10 only needs to be formed at least at the base end of the support bar 12 on the island portion side. For example, as shown in FIG. 3, the opening portion 10 may be formed by entering the island portion 11. (FIG. 7A). Further, one opening 10 (FIG. 2B) or a plurality of openings 10 may be formed over the entire length of the support bar 12 (FIG. 2C).

When a semiconductor device is manufactured using the lead frame shown in FIG. 3B, the support bar extending from the sealing body is cut and removed after the formation of the sealing body. Looking at the frame, there is a form in which a rectangular elongated notch is formed in the support bar instead of the opening, in other words, a form in which two elongated support bars extend from one end of the island portion. However, even such a semiconductor device is included in the semiconductor device of the present invention.

The shape of the opening 10 is not particularly limited, and may be appropriately determined in consideration of the shape of the support bar 12 and the like. FIG. 4 shows another shape of the opening. Since the base end of the support bar 12 in FIG. 4 is divergent, the opening 10 is triangular in FIG. 4A and trapezoidal in FIG. And

The size of the opening is not particularly limited as long as the sealing resin can smoothly pass through the opening, and may be appropriately determined based on the type of the sealing resin. As the sealing resin, generally, a mixture of a filler made of spherical silica and an epoxy resin in a weight ratio of about 8: 2 is used. Since the average particle size of the spherical silica used here is about 20 μm, the width and the height of the opening may be at least 20 μm, but the maximum particle size is 150 μm in consideration of the particle size distribution of the spherical silica. (0.15 mm) or more is preferable from the viewpoint of preventing clogging at the opening.
More preferably, the width and height of the opening are 200 μm (0.
2 mm) or more. The width of the support bar at the periphery of the opening is desirably 0.1 mm or more from the viewpoint of processing accuracy and strength.

The method of forming such an opening is not particularly limited, and a conventionally known forming method such as a punching process or an etching process can be used. When a lead frame is formed by punching a thin metal plate by pressing, it is desirable to form an opening at the same time as forming the lead frame from the viewpoint of production efficiency.

[0019]

According to the lead frame for a semiconductor device of the present invention, since the opening through which the sealing resin flows is formed at least at the base end on the island portion side of the support bar extending from the island portion, high viscosity is obtained. Even when the sealing resin is used, the support bar is not pushed up by the sealing resin, and the back surface of the island portion can be completely exposed to the surface of the sealing body.

When the width of the opening is 0.15 mm or more, the back surface of the island portion can be more reliably exposed to the surface of the sealing body.

In the semiconductor device of the present invention, the lead frame is used as a lead frame, the island portion and the semiconductor element are sealed with a sealing resin, and the back surface of the island portion on which the semiconductor element is mounted is on the surface of the sealing body. Since the semiconductor device is completely exposed, heat generated by the semiconductor element can be efficiently dissipated to the outside.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing one embodiment of a lead frame of the present invention.

FIG. 2 is a diagram for explaining a flow of a sealing resin in a cavity.

FIG. 3 is a diagram showing an example of a form of an opening.

FIG. 4 is a diagram showing an example of the shape of an opening.

FIG. 5 is a plan view of a conventional lead frame.

FIG. 6 is a view showing a sealing step.

FIG. 7 is a diagram for explaining pushing up of a support bar by a sealing resin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Semiconductor element 5 Sealing resin 10 Opening 11 Island part 12 Support bar 16 Sealing body

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M109 AA01 BA01 DB03 FA03 5F061 AA01 BA01 CA21 DD12 5F067 AA03 AB03 BD00 BD05 CA04 DF17

Claims (3)

[Claims] 1. A lead frame for use in a package type semiconductor device in which a back surface of an island portion on which a semiconductor element is mounted is exposed on a surface of a sealing body, wherein at least a base end of a support bar extending from the island portion on the island portion side is provided. A lead frame for a semiconductor device, wherein an opening through which a sealing resin flows is formed. 2. The width and the length of the opening are 0.15 mm.
2. The lead frame for a semiconductor device according to claim 1, wherein: 3. An island portion and a semiconductor element are sealed with a sealing resin using the lead frame according to claim 1 as a lead frame, and a back surface of the island portion is exposed on a surface of a sealing body. A semiconductor device characterized by the above-mentioned.