JPH0793404B2 - Semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to enhancement of adhesion of a resin-sealed semiconductor device to a sealing resin.

[Conventional technology]

A lead frame used for mounting a semiconductor device such as an IC or LSI is formed by forming a plate-like body made of a metal material such as an iron-based material or a copper-based material into a desired pattern by pressing or etching.

Usually, as shown in FIG. 3, a lead frame 1 includes a die pad 11 on which a semiconductor integrated circuit chip (hereinafter, semiconductor chip) is mounted, a plurality of inner leads 12 and inner leads 12 arranged so as to surround the die pad. A tie bar 13 that is integrally connected, and an outer lead 14 that is connected to each inner lead and extends to the outside of the tie bar,
Sidebars 15 and 16 supporting the tiebar 13 from both sides
And a support bar 17 that supports the die pad 11.

A semiconductor device mounted using such a lead frame is as shown in FIG.
The semiconductor chip 2 is mounted on the die pad 11 of, and the bonding pad of the semiconductor chip and the inner lead 12 of the lead frame are connected by the bonding wire 3 of gold wire or aluminum wire, and these are sealed with resin or ceramic. After sealing with the stopper material 4, the tie bar sidebars are cut and the outer leads are bent into a desired shape to complete.

In recent years, with the increase in size of semiconductor devices, the die pads that support them have also become larger.

Therefore, the occupancy rate of the pad in the resin sealing area becomes large, the thickness of the resin in the package area becomes thin, and good adhesion between the sealing resin and the back surface of the die pad cannot be obtained. Further, cracks are likely to occur due to the difference in thermal expansion coefficient between the sealing resin and the die pad, which has been a cause of deterioration in reliability of the semiconductor device.

Conventionally, as a measure for preventing such crack generation, so-called dimple processing has been performed on the back surface of the die pad to form a small hole or a recess by punching or etching, and the resin is poured into the small hole or the recess to form the back surface of the die pad. The method of surely fixing the resin is adopted.

However, with this method, the surface of the die pad is affected, and therefore it is not possible to perform deep processing,
It was difficult to obtain a sufficient effect.

Also, a method of sticking a polyimide tape on the back surface of the die pad has been proposed, but even with this method, it was difficult to obtain a sufficient effect.

[Problems to be Solved by the Invention]

As described above, in the case of high integration, the method of performing dimple processing on the back surface of the die pad in order to improve the adhesiveness with the sealing resin is extremely difficult to adjust because it affects the surface of the die pad. It was not possible to obtain such an effect.

The present invention has been made in view of the above embodiments, and an object of the present invention is to provide a highly reliable semiconductor device having high adhesiveness with a sealing resin when highly integrated.

[Means for Solving the Problems]

Therefore, in the semiconductor device of the present invention, a plate-like body having irregularities or through holes is attached to the back surface of the semiconductor chip mounting portion.

[Action]

According to the above structure, since the back surface of the semiconductor chip mounting portion, the plate-shaped body having irregularities or through holes is attached,
At the time of resin sealing, the resin is also filled in the recesses and hardened, so that the adhesion with the resin becomes extremely good.

Nor.

Further, since the plate-shaped body and the semiconductor chip mounting portion are formed as separate bodies, and the surface of the semiconductor chip mounting portion does not form a through hole, there is no displacement or deformation due to distortion. Further, since it is not necessary to carefully control the processing, the manufacturing is easy, and the mechanical strength of the semiconductor chip mounting portion is not deteriorated.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The lead frame of the embodiment of the present invention is as shown in FIG.
The die pad is characterized in that a metal adhesion reinforcing plate having a small hole is attached to the back surface of the die pad, and the resin can be poured into the small hole. The other parts have the same structure as that shown in FIG.

Next, a method of manufacturing this lead frame will be described.

First, as shown in FIG. 2 (a), a die pad 11 having a thermal expansion coefficient substantially the same as that of a semiconductor chip, for example, a Fe-based band-shaped material containing Ni, is pressed by a usual method.
A plurality of inner leads 12 arranged to surround the die pad, a tie bar 13 integrally connecting the inner leads 12, an outer lead 14 connected to each inner lead and extending outside the tie bar, and a tie bar A lead frame composed of side bars 15 and 16 for supporting 13 from both sides and a support bar 17 for supporting the die pad 11 is formed.

Next, as shown in FIG. 2 (b), an adhesion strengthening plate 20 made of a copper plate having a large number of through holes h and having a thickness of 0.1 mm to 0.25 mm is formed by pressing.

After this, a lead frame is further formed through a plating process and a coining process as required, and then, as shown in FIG. Attach the adhesion strengthening plate 20.

Then, a semiconductor device is completed through steps such as mounting of element chips, wire bonding, and resin sealing.
At the time of resin sealing, the resin is filled in the small holes and hardened, so that the adhesion is extremely good.

In addition, since this adhesion strengthening plate is made of a copper plate, it has a thermal expansion coefficient close to that of the sealing resin and exhibits a good heat dissipation effect.

Further, since the adhesion strengthening plate is formed as a separate body from the die pad, there is no risk of affecting the surface of the die pad or causing positional displacement or deformation due to strain caused by mechanical processing, and the processing is easy.

In addition, in the said Example, you may comprise so that an adhesion strengthening agent etc. may be poured into the through-hole of an adhesion strengthening board in order to further improve adhesiveness.

Further, in the above-mentioned embodiment, the adhesion strengthening plate was formed to have a through hole, but the position and shape of the through hole can be appropriately modified without being limited to the embodiment, and is not necessarily the through hole. It may be uneven or uneven.

Furthermore, in the above embodiment, the adhesion strengthening plate was made of copper, but it is not necessarily a metal plate and may be a resin plate, or these may be attached using an adhesive tape.

Although the small holes of the adhesion strengthening plate are formed by pressing in the above embodiment, they may be formed by etching.

In addition, in the above embodiment, the semiconductor device using the wire bonding type lead frame has been described.
Needless to say, the present invention is not limited to the wire-bonding type lead frame and can be applied to the wireless-bonding type lead frame.

〔The invention's effect〕

As described above, according to the present invention, since the plate-shaped body having the irregularities or the through holes is attached to the back surface of the semiconductor chip mounting portion, the resin is filled also in the irregularities during the resin sealing. Since it is cured, it is possible to obtain a highly reliable semiconductor device having extremely good adhesion to the resin.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor device according to an embodiment of the present invention, FIGS. 2 (a) to 2 (c) are perspective views of a main part of the lead frame, and FIG. 3 is a diagram showing a normal lead frame, FIG. 4 is a diagram showing an ordinary semiconductor device. 1 ... Lead frame, 2 ... Semiconductor chip, 3 ... Wire, 4 ... Sealing material, 11 ... Die pad, 12 ... Inner lead, 13 ... Tie bar, 14 ... Outer lead,
15,16 …… Side bar, 17 …… Support bar, h …… Small hole, P …… Polyimide resin, 20 …… Adhesion strengthening plate.

Claims (1)

[Claims] 1. A semiconductor chip mounting part, a semiconductor chip mounted on the semiconductor chip mounting part, a plurality of inner leads formed so as to surround the semiconductor chip, and an outer continuous with the inner leads. In a resin-sealed semiconductor device having a lead, which electrically connects the semiconductor chip and an inner lead and is resin-sealed while leaving a part of the outer lead, A semiconductor device, characterized in that a plate-like body having irregularities or through holes is attached.