JPH0590480A - Lead frame and method of manufacturing semiconductor device using the same - Google Patents

Abstract

(57) [Summary] (Correction) [Object] It is an object of the present invention to provide an inexpensive and highly reliable semiconductor device which prevents deformation of the tips of the inner leads. According to the present invention, every other inner lead near the semiconductor element mounting portion is alternately shortened and shortened. IS
In contrast, the semiconductor chip is connected to the semiconductor chip through a conductor pattern formed on the insulating film 11 attached on the inner lead. I am trying to configure the lead.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a method of manufacturing a semiconductor device using the same, and more particularly to a lead frame for mounting a high density semiconductor device.

[0002]

2. Description of the Related Art As semiconductor devices have become smaller and thinner, the demands on lead frames used for assembling them have become stricter.

For example, since the size of a semiconductor chip is reduced without changing the degree of integration of the semiconductor chip, the density is high, and the lead frame used here tends to increase only the number of leads without changing the pad size. For this reason, the inner lead becomes thinner and longer, and the mechanical strength is reduced, and it becomes difficult to maintain the accuracy due to a minute external force, processing strain, and the like. And such deformation of the inner leads is apt to cause short-circuiting of the leads or defective bonding, resulting in a decrease in yield of the lead frame,
This is one of the causes of the decrease in reliability of the semiconductor device.

In order to solve such problems, various measures such as increasing the precision of the stamping die and annealing the lead frame during the working process have been tried, but the working process is complicated and the yield is increased. It causes a number of problems, such as lowering the cost and causing a price increase due to excessive precision requirements.

[0005]

As described above, according to the conventional lead frame, the mechanical strength is lowered as the density is increased, and the lead short circuit or the bonding failure due to the deformation of the inner lead is likely to occur. This is one of the causes of reduction in yield of lead frames and reduction in reliability of semiconductor devices.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device which prevents deformation of the tips of the inner leads and is inexpensive and highly reliable.

[0007]

Therefore, in the present invention, the inner leads near the semiconductor element mounting portion are alternately shortened, and the shortened ones are insulated by being attached to the inner leads. The inner lead is connected to the semiconductor chip through the conductor pattern formed on the flexible film, and the inner lead having a two-layer structure is substantially formed in the high-density region at the tip of the inner lead.

That is, in the lead frame of the present invention,
A semiconductor element is mounted on a plurality of inner leads that are arranged around the semiconductor chip mounting portion and extend in a radial pattern so that the tips are alternately long and short, and that the semiconductor elements are mounted substantially parallel to the inner leads in correspondence with the inner leads. An insulating film having a conductor pattern that extends toward the mounting portion and has its outer end electrically connected to the shorter one of the inner leads is attached, and the inner lead tip has a two-layer structure. Is composed of.

Here, it is desirable that the conductor pattern on the insulating film overlaps the inner lead.

Further, according to the method of the present invention, a plurality of inner leads which are arranged around the semiconductor chip mounting portion and radially extend so that the tips alternately have lengths, and the outer leads which extend respectively to the inner leads. And a conductor pattern that extends toward the semiconductor element mounting portion substantially parallel to the inner lead corresponding to the shorter one of the inner leads. And then electrically connect each conductor pattern to the short one of the inner leads, and mount the semiconductor chip on the semiconductor element mounting part of the lead frame body. Connect each conductor pattern and the long one of each inner lead to the semiconductor chip by wire bonding. There.

[0011]

According to the above structure, since the inner leads have different lengths alternately, the inner lead width and the distance between the inner leads can be increased, and the mechanical strength is greatly increased.

Further, since the inner lead width and the distance between the inner leads can be increased, the workability of wire bonding is improved, and a bonding error is suggested, and the reliability is improved.

If the conductor pattern on the insulating film overlaps the inner leads, the capillaries are stabilized during the wire bonding process.

Further, if the conductor pattern on the insulating film is formed wide at the end portion, the bonding becomes easy.

Further, if the conductor pattern is projected outward and a bump or the like is formed at the tip, the connection with the inner lead can be made by direct bonding. Further, through holes may be formed at corresponding positions of the insulating film, and the inner leads may be electrically connected through the through holes.

Further, since the inner lead tip positions are actually formed alternately when mounting the chip, it is possible to bring the inner lead tip positions closer to the chip and save the bonding wire. In addition, it is possible to prevent contact between wires (wire touch).

Further, since half of the tip portion of the inner lead is formed by patterning a conductive film on the insulating film by etching or by a thick film printing method, the conductive film is largely formed. The pattern accuracy is extremely good.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIGS. 1 (a) and 1 (b) are a plan view and an enlarged view of a main part (the mold resin is omitted) of a semiconductor device formed by the method of the present invention, and FIGS.
(c) is a diagram showing a manufacturing process diagram of a semiconductor device of an example of the present invention.

This semiconductor device has a plurality of inner leads 1L and 1S extending radially from a position spaced from the semiconductor element mounting portion (die pad) 2 by a predetermined distance and having tips alternately long and short, and each inner lead. 1, a lead frame body R1 having an outer lead 3 integrally formed to extend therewith, and a gold extending in parallel with the inner lead corresponding to the shorter one 1S of the inner leads of each inner lead body. A film portion R2 formed of a polyimide film 11 having a pattern 1P and having an opening h in the center, and a semiconductor element mounting portion 2 exposed in the opening h.
And a semiconductor chip 5 fixed to the film chip. One end of the gold pattern 1P on the film portion is connected to a short one of the inner leads of the lead frame body R1 via bonding wires 6a, and the other end is bonded. It is electrically connected to the semiconductor chip via the wire 6b. The tip of the long inner lead 1L is electrically connected to the semiconductor chip via the bonding wire 6b. Here, 4 is a support bar.

Next, a method of manufacturing this semiconductor device will be described.

First, as shown in FIG. 2 (a), a region for mounting a semiconductor element formed to have a sufficiently large size by processing a strip material made of a copper alloy by a stamping method ( Die pad 2 and a large number of inner reels arranged at predetermined intervals from the die pad 2 such that the tips of the die pad 2 are alternately long and short.
The lead frame body R1 including the leads 1L and 1S and the outer lead 3 arranged so as to be connected to the inner leads is molded.

Next, as shown in FIG. 2 (b), a substrate is prepared in which a gold foil 1P is bonded to the surface of the polyimide resin 11 and is patterned by an etching method to correspond to the tips of the inner lead bodies. Thus, a gold pattern that extends toward the die pad 2 is formed to form the film portion R2.

Then, as shown in FIG. 2 (c), the film portion R2 is attached to the die pad 2 of the lead frame body R1 so that the film surface faces downward, and the gold pattern 1P of the film portion is attached by wire bonding. The lead frame is completed by connecting the outer end and the short inner lead 1S.

Further, the semiconductor chip 5 is placed and fixed on the die pad 2 of the lead frame body R1.

Further, the tip of the long inner lead 1L and the bonding pad of the chip 5 closest to this are connected via a bonding wire 6b, and the inner end of the gold pattern 1P and the chip 5 are connected.
Bonding wire 6
Connect via b.

After this, a semiconductor device is completed through a molding step, a tie bar and a frame body are cut off, and a molding step of folding the outer lead into a desired shape.

In the semiconductor device thus formed, the inner lead width can be increased and the inner lead interval can be increased at the tip portion, so that the mechanical strength of the lead frame is greatly increased. Will be good.

In wire bonding, since the bonding positions of the lead frame are substantially alternating, the lead frame can be brought closer to the chip, the bonding wire can be saved, and the mutual contact of the wires can be prevented. it can.

Further, since the conductor pattern is formed on the polyimide film, it can be formed sufficiently thin, and the bonding can be performed while maintaining the positional accuracy of the tips of the inner leads at a higher level, which is highly reliable. It will be expensive.

Since the gold pattern 1P (the tip of the inner lead) is formed by patterning a gold foil film bonded on a polyimide film by etching, it should be made much thinner than when it is not supported by the film. And the pattern accuracy is extremely good,
The cost can also be reduced significantly.

As another embodiment of the present invention, both ends of the conductor pattern may be formed wide as shown in FIG.
This structure improves the bondability.

Further, in the above embodiment, the lead frame and the film portion are connected by wire bonding, but the invention is not limited to wire bonding and direct bonding may be used.

[0034]

As described above, according to the present invention, the inner leads near the semiconductor element mounting portion are alternately shortened, and the shortened ones are attached to the inner leads. Since the inner leads are connected to the semiconductor chip via the conductor pattern formed on the insulating film and the high density area at the tip of the inner leads substantially constitutes the two-layer inner lead, Also in this case, a highly reliable semiconductor device can be easily obtained by using a thin lead frame having high mechanical strength.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a manufacturing process of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1S Inner lead (short) 1L Inner lead (long) R1 Lead frame body R2 Film part 1P Gold pattern 2 Die pad 3 Outer lead 4 Support bar 5 Semiconductor chip 11 Polyimide film

Claims (2)

[Claims] 1. Arranged around a semiconductor chip mounting portion,
A lead frame main body portion having a plurality of inner leads radially extending so that the tips alternately alternate with each other, and outer leads respectively extended to the respective inner leads, and the lead frame main body portion, the inner surface being attached to the lead frame main body portion, Insulating film provided with a conductor pattern extending toward the semiconductor element mounting portion substantially parallel to the inner lead corresponding to the shorter one of the leads, the outer end of the conductor pattern and the inner lead A lead frame characterized by being electrically connected to a short object. 2. Arranged around a semiconductor chip mounting portion,
A lead frame body portion forming step of forming a lead frame body portion having a plurality of inner leads radially extending so that the tips alternately alternate with each other, and outer leads respectively extending to the inner leads; An insulating film that is attached to the main body and forms an insulating film having a conductor pattern that extends toward the semiconductor element mounting portion substantially parallel to the inner leads corresponding to the shorter one of the inner leads. A film forming step, and an insulating film attaching step of electrically connecting each of the conductor patterns and a short one of the inner leads together with attaching the insulating film on the lead frame main body, A semiconductor chip mounting step of mounting a semiconductor chip on a semiconductor element mounting portion of the lead frame body; A method of manufacturing a semiconductor device, comprising: a bonding step of connecting each conductor pattern on the edge film and the long one of the inner leads to a semiconductor chip by wire bonding.