JP2685582B2 - Lead frame and semiconductor device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a technique for producing a lead frame and a technique for constructing a semiconductor device using the lead frame, in particular,
The present invention relates to a technique effective for solving various problems caused by a cutting process when a dam bar is provided, and a technique for forming a semiconductor device using a new lead frame.

[Prior Art] In recent years, IC / LSI devices have been tending toward higher performance and diversification. In particular, ASIC (Applic
(IC), which is a special purpose IC called "ation specific IC". In particular, logic IC / LSI devices tend to be diversified, and the packaging density is also increasing accordingly, so that the number of pins is increasing.

Also, in mold type IC / LSI, die bonding is performed on a metal lead frame with a shape similar to a 36 mm film, each electrode of the semiconductor chip and the lead frame are connected with Au wires, etc., and then fixed with mold resin. Is produced.

FIG. 9 shows an example of a lead frame used in such a mold type IC / LSI.

As shown in FIG. 9, the lead frame includes an outer lead 1, an inner lead 2 formed at an end of the outer lead 1, and a dam bar 3 for connecting and fixing a part of the outer lead 1 adjacent to each other at a predetermined pitch. And a tab 4 arranged at the facing portion of each inner lead 2.

When making a semiconductor device using the lead frame,
The semiconductor chip is positioned and bonded on the tab 4. Next, the bonding pad of the chip and a predetermined region of the lead frame are electrically connected by the wire bonding technique. Further, the lead frame after wire bonding is arranged in a mold, and an epoxy resin (mold resin) is poured into the mold for resin molding. At this time, the dam bar 3 functions to prevent the injected resin from leaking out. Then, the leads protruding around the resin are cut into a predetermined length, and the dam bar 3 is cut. Thereby, the independent outer lead 1 is formed.

As for this kind of lead frame,
For example, JP-A-61-152051 and "Electronic Materials" 1988
April issue, pages 85 to 90, "Features of ASIC general-purpose lead frame".

[Problems to be solved by the invention]

However, in the semiconductor device using the lead frame in which the dam bar is formed as described above, the lead pitch becomes small, or if the multi-tiered lead frame structure is used for the purpose of multiple pins, it becomes difficult to cut and separate the dam bar. .

Therefore, the existence of the dam bar has been an obstacle to realizing a multi-pin structure and a multi-layered lead frame structure.

Therefore, an object of the present invention is to provide a technique that does not require a dam bar and does not require cutting and separating processing of the dam bar.

Another object of the present invention is to provide a technique that enables a multi-pin structure and a multi-tier stacking by using a lead frame having no dam bar.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of this specification and the accompanying drawings.

[Means for solving the problem]

The outline of a typical invention disclosed in the present application will be briefly described as follows.

That is, in a lead frame having a tab portion on which a semiconductor element is mounted, an inner lead connected to the semiconductor element via a thin metal wire, and an outer lead portion integrally connected to the inner lead portion, the Protrusions or cutouts are provided on the inner lead portion in the portion covered by the mold or in the vicinity of the outer edge of the resin mold, and a dam stopper member made of an insulating material is provided between the protrusions or the cutouts. Is.

[Action]

According to the above-mentioned means, the dam stop member made of an insulating material provided between the inner leads functions as a dam bar integrally formed with a conventional lead, and since it is a non-conductor, it forms an electric conductor. Never. Therefore, it is not necessary to remove it after resin molding,
The cutting and removing process becomes unnecessary. Therefore, it is possible to increase the number of pins.

〔Example〕

FIG. 1 is a plan view showing an embodiment of a lead frame according to the present invention.

In FIG. 1, the same reference numerals are used for the same parts as those in FIG. 9, and thus the duplicate description will be omitted. The feature of this embodiment is that the dam bar 3 conventionally provided in the inner lead portion is eliminated, and the dam stop member 5 is provided at the position where the dam bar 3 is provided so as to connect the inner leads 2 to each other. It is the one.

The dam stopping member 5 is formed by using a non-conductive material, for example, an epoxy resin, an acrylic resin, or an epoxy resin containing reinforcing fibers such as glass fibers, and fixing the same between the leads. Further, when the dam stopping member 5 is fixed between the leads, an engaging member is provided at the side end portion of the lead so that the dam stopping member 5 is not peeled off during transportation.

That is, as shown in FIG. 2, the protrusion 6 is provided on the side portion,
Alternatively, as shown in FIG. 3, the notch 7 is provided so that the dam stopping member 5 fixed between the leads can be securely engaged, and the dam stopping member 5 is prevented from falling off.

The dam stopping member 5 can be formed by punching a lead frame into a predetermined pattern by pressing,
The resin material may be poured into a portion where the dam bar was formed and solidified. The unnecessary portion (protruding portion) is removed if necessary.

Since the dam stopping member 5 is an insulating material, even if it is bridged between the leads, it does not affect the circuit electrically. Therefore, the resin molding after wire bonding can be performed without removing the dam stopping member 5. Since it is not necessary to remove the dam stopping member 5, various problems associated with cutting and removing, which are problems of the conventional technique, do not occur.

The present invention is of course effective when applied to a lead frame having leads formed in two directions as shown in FIG. 1, but leads are formed in four directions as shown in FIG. It is particularly suitable for the lead frame 8 having a structure in which the dam bar 3 is not provided integrally with the outer lead 1. In this case, since the number of pins is increased and the lead interval is close, the dam stopping member 5 is formed in a strip shape so as to connect the inner leads 2 to each other, as shown in FIG.

Next, an embodiment of a semiconductor device using the lead frame having the above structure will be described.

FIG. 6 is a sectional view showing an embodiment of the semiconductor device according to the present invention.

The manufacturing process of the semiconductor device shown in FIG. 6 will be described. First, the semiconductor element 10 is placed on the tab 4 of the lead frame shown in FIG. 1 using an automatic pattern recognition device. An epoxy resin containing Ag (Ag paste) is applied on the tab 4 in the previous step, and the semiconductor element 10 is temporarily fixed only by pressing the semiconductor element 10. Then, the epoxy resin containing Ag is cured at 150 to 200 ° C., and the semiconductor element 10 and the lead frame are electrically connected by Ag in the resin.

Next, using the Au wire 11, the bonding pad of the semiconductor element 10 and a predetermined region of the lead frame are electrically connected, that is, wire bonding is performed by an automatic bonder. Further, the lead frames after wire bonding are arranged in a mold, and an epoxy resin (mold resin) is poured into the mold to form a resin mold 12.
Then, the outer leads protruding around the resin are cut into a predetermined length. Thereby, the independent outer lead 1 is formed.

At this time, as shown in FIG. 7, the dam stopping member 5 is
There is a case where the mold resin in which the resin is hardened is protruding to the outside. In this case, it is removed by some method. Alternatively, since it does not affect the performance of the product, it may be left as it is.

FIG. 8 is a sectional view of a main portion showing another embodiment of the semiconductor device.

This embodiment has a multi-layered structure of leads, and is characterized in that, as shown in FIG. 8, the outer leads 1b are arranged so as to overlap the outer leads 1a. In this case, the insulator 13 is interposed between the leads so that the upper and lower electrodes do not come into contact with each other. This insulator
An epoxy insulating tape is used for 13, for example.

In this way, by forming the leads in a multi-tiered structure, for example, two-tiered leads can process the number of wires twice as many as the number of leads on a plane, and high-density mounting becomes possible. This can be achieved because the dam bar can be eliminated integrally with the lead.

Although the invention made by the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. .

〔The invention's effect〕

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

(1). That is, a lead frame having a tab portion on which a semiconductor element is mounted, an inner lead portion connected to the semiconductor element through a thin metal wire, and an outer lead portion integrally connected to the inner lead portion, which is a resin Protrusions or notches are provided on the inner lead portion at a portion covered by the resin mold during molding or a portion near the outer edge of the resin mold, and a dam stopper member made of an insulating material is provided between the protrusions or the notches. As a result, the dam bar formed integrally with the lead becomes unnecessary, and the cutting and separating process of the dam bar can be made unnecessary. In addition, the dam stop member is securely engaged by the protrusion or the notch provided on the inner lead portion, and the dam stop member can be prevented from falling off.

(2). According to the above (1), the number of pins of the semiconductor device can be increased and a multi-tiered lead frame structure can be realized. In particular, it is suitable for a multi-pin logic semiconductor device.

[Brief description of the drawings]

1 is a plan view showing an embodiment of a lead frame according to the present invention, FIGS. 2 and 3 are plan views showing a lead structure of an installation portion of a dam stop member according to the present invention, and FIG. 4 is a view showing the present invention. 5 is a plan view showing another embodiment of the lead frame according to FIG. 5, FIG. 5 is a plan view showing an example of forming a dam stop member corresponding to the lead frame shown in FIG. 4, and FIG. 6 is an embodiment of a semiconductor device according to the present invention. FIG. 7 is a plan view for explaining the removal of the dam stop member of the semiconductor device of FIG. 6, FIG. 8 is a cross-sectional view showing another embodiment of the semiconductor device according to the present invention, and FIG. It is a top view which shows the structure of the conventional lead frame. 1,1a, 1b …… Outer lead, 2 …… Inner lead,
4 ... Tab, 5 ... Dam stop member, 6 ... Protrusion, 7 ...
Notches 7, 8 ... Lead frame, 10 ... Semiconductor element,
11 …… Au wire, 12 …… Resin mold, 13 …… Insulator.

Claims (4)

(57) [Claims] 1. A tab portion on which a semiconductor element is mounted, an inner lead portion connected to the semiconductor element via a thin metal wire,
A lead frame having an outer lead portion integrally connected to the inner lead portion, the protrusion being formed on the inner lead portion at a portion covered by the resin mold during resin molding or a portion near an outer edge of the resin mold. A lead frame, characterized in that cutouts are provided, and a dam stop member made of an insulating material is provided between the protrusions or between the cutouts. 2. The lead frame according to claim 1, wherein a plurality of the lead frames each having a different connection destination are laminated while being insulated in the thickness direction. 3. The dam stopping member is formed by pouring a resin material between the projections or the notch portions of the inner lead portion and solidifying the resin material.
Lead frame as described. 4. A semiconductor device comprising a lead frame according to claim 1, 2 or 3, on which a semiconductor chip is mounted, and a predetermined portion which has been assembled is resin-molded.