JPH06132350A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of a short circuit between the adjacent electrodes due to the deformation of a ball bump in a semiconductor device with which an inner lead bonding operation is conducted on the ball bump on an element electrode. CONSTITUTION:An inner lead 2 is directly connected to the ball-like bump 5 to be formed on a plurality of electrode parts of a semiconductor element, and this lead 2 is packaged in such a manner that it is led to outside in this semiconductor device. An irregular part is formed on the surface where the lead 2 and the bump 5 are connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device for inner lead bonding. In recent years, the degree of integration of semiconductor devices has been increasing more and more, and some of them have narrow gaps between electrodes, and some of them have semiconductor elements mounted on a flexible flexible plate in order to reduce the thickness.
In such a case, since it is difficult to connect the pads of the semiconductor element to the leads by wire bonding, the inner lead bonding method of the TAB tape has been used instead.

The inner lead bonding method is a method in which bumps are formed on the electrode portions of a semiconductor element with gold or the like, and the leads are arranged on the bumps and heated and pressed to directly connect the leads to the bumps.

[0003]

2. Description of the Related Art Conventionally, bumps of a semiconductor element in inner lead bonding have been formed by plating with gold or the like. However, in the case of a gate array or the like that produces a large number of products in small quantities, it is necessary to manufacture each bump from a mask in order to form the bumps, and the labor and cost thereof are enormous.

Therefore, a technique using a ball pump which can be formed relatively easily is drawing attention. This is for forming a spherical bump on the electrode portion of a semiconductor element, and is a conventional wire bonding technique applied. A conventional semiconductor device in which inner lead bonding is performed using ball bumps will be described below with reference to the drawings.

First, the formation of ball bumps, which is the same as the conventional wire bonding technique, is shown in FIG.
A capillary 1 for supplying a gold wire 10 is used as shown in FIG. A spark is generated between the torch electrode 11 and the wire 10 led to the tip of the capillary 9 to make the tip of the wire spherical (ball 12) as shown in FIG. 6 (B). This ball 12 is attached to the semiconductor element 1 as shown in FIG.
Bonding is performed on the electrodes of to form ball bumps 13 as shown in FIG.

On the other hand, the inner lead is punched and fixed to the flexible plate to form a TAB tape. (Not shown) While supplying this TAB tape, the semiconductor element 1 is arranged on the support base 15 containing the heater 16 as shown in FIG. 7, and the inner lead 14 and the bump 13 are made to correspond to each other and the heater 18 is incorporated. By applying pressure and heat with the bonding tool 17, a connected state as shown in FIG. 8 is obtained. still,
FIG. 8 is a top view, in which the leads 14 are fixed to the TAB tape 19 and are integrated by connecting the semiconductor element 1 to the leads 14. However, the leads on the three sides are omitted.

Such a TAB tape 19 is cut at a predetermined position, and after outer lead bonding is sealed with a resin 20 as shown in FIG. 9, leads 21 are packaged so as to be led out to the outside. .

[0008]

FIG. 10 shows an enlarged cross-sectional view of the connecting portion between the inner lead and the bump. The ball bump has a higher gold purity and is softer than the plated bump, and since it has a spherical shape, it is easily deformed when connected to a lead. In particular, when the lead and the bump are misaligned with each other, as shown in FIG.
Is connected to the inclined portion of the bump 5, and the lead 2 slides on the inclined portion, thereby crushing the bump 5 to the adjacent connection portion side and short-circuiting due to contact with the adjacent electrode 4, or
As shown in FIG. 0 (B), the lead 2 may sink close to the surface of the semiconductor element and contact the edge portion of the semiconductor element to cause a short circuit.

[0009]

In the semiconductor device of the present invention for solving the above problems, the inner leads 2 are directly connected to the ball-shaped bumps 5 formed on the plurality of electrode portions 4 of the semiconductor element 1. In the semiconductor device in which the lead 2 is packaged so as to be led out to the outside, a recessed portion, a through hole 6, or an uneven portion due to a saw tooth 7 is formed on a surface of the lead 2 connected to the bump 5. It is characterized by being formed.

[0010]

According to the present invention as described above, the depression, the through hole or the saw of the lead firmly sticks to the soft ball bump, and the inner lead is not displaced. Therefore, the bumps are not crushed and the possibility of short circuit is reduced.

[0011]

EXAMPLE A specific structure of the semiconductor device of the present invention will be described below. Bump formation for semiconductor elements is
As described in the section of the conventional technique (FIG. 6), the wire bonding technique is applied. The torch electrode 11 is arranged below the tip of the capillary 9 for supplying the gold wire 10,
A spark is generated between the tip of the capillary 9 and the wire 10 led out from the tip of the capillary 9 so that the tip of the wire is spherical (ball 1).
Set to 2).

Then, the semiconductor element 1 is transferred below the capillary, and the ball is bonded onto the electrode of the semiconductor element 3 by lowering the capillary. This bonding is performed twice by shifting their positions, and after the second bonding, the wire 10 is cut. However, the second bonding is performed without forming a ball at the tip of the wire. With this bonding, the ball bumps 5 are formed in a stepped shape as shown in FIG. 2A depending on the shape of the tip of the capillary 1.

One embodiment of the present invention utilizes this bump shape. That is, the shape of the connecting portion of the lead is made to correspond to the shape of the bump, and as shown in FIGS. 1 and 2A, the depression 3 which is slightly larger than the convex portion on the upper side of the bump 5 is formed. The recess 3 can be formed at the same time by arranging a die that protrudes when the lead is punched out. A lead having such a depression 3 is fixed to a flexible plate to form a TAB tape.

The inner lead is formed by tinning the surface of a base material such as copper or iron. This TA
While supplying the B tape, as described with reference to FIG.
The semiconductor element is arranged at a predetermined position, the inner lead and the bump are made to correspond to each other, and they are connected by applying pressure and heat.

This connection is realized by making the gold, which is the bump material, and the tin plated on the leads into a eutectic state. In the case of this embodiment, the connection state is shown in FIG.
Since the bumps and the leads are engaged with each other, the leads are not displaced or connected at an angle, and the bumps are not deformed unevenly.

FIG. 3 is a perspective view of the lead of the second embodiment, but the same effect can be obtained by forming the through hole 6 corresponding to the bump shape instead of the depression as shown in FIG.
This through hole 6 can be formed by punching or etching. Next, a third embodiment in which the lead shape is changed will be described with reference to FIG. 4A and 4B show a sawtooth shape of the connecting portion of the lead, and FIG. 4A is a perspective view of the lead.
(B) is a cross-sectional view showing a contact state with a bump. In this example, when the angle is set to an acute angle, the bumps are firmly stuck to the bumps and the positional deviation does not occur.

Furthermore, a fourth embodiment is shown in FIG. FIG. 5 is a perspective view of the lead, in which the thickness of the lead 2c provided with the recess 3a is increased at the connecting portion, and particularly, the lead 2c is projected downward from other portions. This is to prevent the leads from coming into contact with the edge of the device by sinking the leads into the bumps due to the provision of the recess 3a and sinking on the surface of the semiconductor device. This is true not only in the case of the depression but also in the case of the through hole and the saw tooth.

As described above, by forming the thick portion in the connecting portion of the lead, the possibility of occurrence of short circuit can be further reduced. The lead thickness can be changed at the same time when the lead is punched and formed.

[0019]

According to the semiconductor device of the present invention, leads can be reliably and stably connected to ball bumps formed by using a simple conventional wire bonding technique, and the bumps are biased. It is possible to prevent the occurrence of short circuit without deformation.

[Brief description of drawings]

FIG. 1 is a perspective view showing a connecting portion between a lead and a ball bump in a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view showing a connecting portion between a lead and a ball bump in the semiconductor device of the present invention.

FIG. 3 is a perspective view showing a lead shape according to a second embodiment of the present invention.

FIG. 4 is a perspective view and a sectional view showing a lead shape according to a third embodiment of the present invention.

FIG. 5 is a perspective view showing a lead shape according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a method of forming ball bumps.

FIG. 7 is a cross-sectional view illustrating a step of connecting leads and ball bumps.

FIG. 8 is a plan view in which a semiconductor element is connected to leads and is in a TAB tape state.

FIG. 9 is a cross-sectional view of a packaged semiconductor device targeted by the present invention.

FIG. 10 is a sectional view of a connecting portion for explaining a conventional problem.

[Explanation of symbols]

 1-Semiconductor element 2-Lead 3-Recess 4-Electrode 5-Ball bump 6-Through hole 7-Saw tooth 8-Thick section

Claims (2)

[Claims] 1. A package in which an inner lead (2) is directly connected to a ball-shaped bump (5) formed on a plurality of electrode portions of a semiconductor element, and the lead (2) is led out to the outside. The semiconductor device is characterized in that a recess to be fitted with the bump is formed on a surface of the lead (2) connected to the bump (5). 2. The semiconductor according to claim 1, wherein the recess of the lead (2) is formed by a recess (3) or a through hole (6) corresponding to the shape of the bump (5). apparatus.