JPH0546271Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an insulator-sealed semiconductor device having a structure in which two electrode bodies are connected by a thin lead wire.

Prior Art FIG. 4 is a perspective view showing a part of a conventional resin-sealed composite IC. This resin-sealed composite IC has a supporting electrode body 1 formed from a lead frame and wiring electrode bodies 2 and 3, and a power transistor chip 4 is fixed on the supporting electrode body 1 with solder (not shown). has been done. A plurality of electrodes (bonding pads) are formed on the upper surface of the power transistor chip 4, but are not shown. Two thin lead wires 5 are connected to the bonding pad.
The thin lead wire 5 is connected to the wiring electrode body 2 across the wiring electrode body 3 as shown in the figure. As a result, the wiring electrode body 3 and the thin lead wire 5 form multiple wirings. Next, a method for connecting thin lead wires will be explained with reference to FIG.

First, as shown in FIG. 5A, a thin lead wire 52 is sent out from the center hole 51 of a pipe-shaped capillary 50 of a wire bonder, and a ball 53 is formed at the tip of the thin lead wire 52 using an electric spark, a hydrogen flame, or the like. The diameter of the ball 53 is about 2 to 3 times the diameter of the thin lead wire 52.

Next, as shown in FIG. 5B, the first electrode body 5
First bonding is performed by pressing the ball 53 onto the capillary 4 with the tip of the capillary 50. At this time, the first electrode body 54 is preheated to 200 to 250°C. Further, ultrasonic vibration is applied to the capillary 50 in the direction indicated by an arrow 55 perpendicular to the connection direction of the thin lead wire 52. As a result, the first electrode body 5
4 is formed with a first bonding portion 52a to which a thin lead wire 52 is connected like a nail head.

Next, as shown in FIG. 5C, the capillary 5
The capillary 50 is moved toward the second electrode body 56 while letting out the thin lead wire 52 by raising the capillary 50 and drawing it widely.

Thereafter, as shown in FIG. 5D, second bonding is performed on the second electrode body 56. That is, the second electrode body 56 is preheated to 200 to 250° C. as described above, and the same ultrasonic vibration as described above is applied to the capillary 50. In this state, by pressing the thin lead wire 52 against the second electrode body 56 in the radial direction, the thin lead wire 52 and the second electrode body 56 are connected, and a second bonding portion 52b is formed. Note that the steps shown in FIGS. 5B and 5D may be performed by a thermocompression bonding method using only heating of the electrode body or an ultrasonic method using only heating using ultrasonic vibration.

Finally, connect the capillary 5 as shown in Figure 5E.
0 to a certain height, the capillary 50 is further raised while holding the thin lead wire 52 with a clamp, and the thin lead wire 52 is cut. In a narrow sense,
The first bonding method is called nail head bonding, and the second bonding method is called static bonding, but here they are collectively referred to as the nail head bonding method. As shown in FIG. 5D, on the first bonding side, the angle α of the thin lead wire 52 with respect to the first electrode body is almost a right angle, and the distance between the thin lead wire 52 that straddles above and the first electrode body is long. Become. On the other hand, on the second bonding side, the angle θ of the thin lead wire 52 with respect to the second electrode body is an acute angle, and the thin lead wire 52 spanning over
The distance between the electrode body and the second electrode body becomes shorter.

Problems to be Solved by the Invention In the past, the thin lead wires came into contact with the wiring electrode body due to the thin lead wires hanging down, causing short-circuit failures. That is, as shown in FIG. 4, a thin lead wire 5 is connected across the wiring electrode body 3. Due to the demand for higher integration of semiconductor devices, wiring tends to become more complex. For this reason, it is often necessary to make a connection across the wiring electrode body.

By the way, the wiring electrode body 3 formed as a third electrode body between the electrode on the power transistor chip 4 which is the first electrode body and the wiring electrode body 2 which is the second electrode body is connected to the thin lead wire 5. It is a non-connected wiring body. For this reason, the thin lead wires 5 are connected in a large arc during wire bonding, so that the distance between the thin lead wires 5 and the wiring electrode body 3 is maintained as much as possible. The thin lead wire 5 is connected to the power transistor chip 4 at the first bonding part and to the wiring electrode body 2 at the second bonding part by the above-mentioned nail head bonding method. Further, the first bonding portion is located at a position higher than the second bonding portion by approximately the thickness of the power transistor chip 4. Therefore, the wiring electrode body 3 is
On the supporting electrode body 1 side, the distance to the thin lead wire 5 becomes long, but on the wiring electrode body 2 side, the distance to the thin lead wire 5 becomes short.

The reality is that the normally used fine gold lead wire with a diameter of about 30 μm is thin and soft, so it cannot be expected to have sufficient strength. For example, the thin gold lead wire connecting the first electrode body and the second electrode body is
During transfer molding, resin injection pressure sometimes caused loop sagging due to its own weight. Normally, for a thin gold lead wire with a diameter of 25 to 30 μm, the connection distance L is limited to 3 mm. If the connection distance L exceeds 3 mm, loop sag will occur due to its own weight. In reality, since the resin injection pressure during transfer molding must be taken into account, the practical length of the connection distance L becomes even shorter. In order to shorten the connection distance L, it is conceivable to reduce the width of the unconnected wiring body. However, due to restrictions such as weakening of the lead frame's mechanical strength, it is not possible to make it very thin. Therefore, in the example shown in FIG. 4, the connection distance L is long, 3.3 mm, and loop sagging is likely to become a problem.

Further, the wiring electrode body 2, which is the second bonding portion of the thin lead wire 5, is located on the side surface of the resin sealing body,
When the sealing resin is injected from the resin injection hole provided on the side surface, the thin lead wire 5 is particularly susceptible to loop sag due to the influence of the injection pressure of the resin. Therefore, due to the combination of these factors, an accident occurs in which the thin lead wire 5 is connected to the wiring electrode body 2 side of the wiring electrode body 3, which is one of the causes of lowering the manufacturing yield.

One possible way to prevent short-circuit failures caused by loop sagging is, for example, by increasing the diameter of the thin lead wire to increase its strength, but this is not suitable for practical use because gold is expensive. . Another possible method is to perform a step process in which at least one of the first electrode body and the second electrode body is raised by a certain height. but,
Because the lead frame has steps, handling of the lead frame becomes complicated and productivity decreases.
In particular, there is a drawback that the supporting structure of the lead frame during bonding becomes a non-planar structure and becomes complicated.

As a means for solving the above problem, for example, a method of shortening the distance between the first electrode body and the second electrode body and shortening the connection distance of the thin lead wire can be considered. However, as semiconductor devices become more highly integrated, wiring tends to become more complex. For example, it is necessary to provide a third electrode body such as a wiring electrode body between the first electrode body and the second electrode body. It was hot. In such a case,
There is also a limit to shortening the distance between the first electrode body and the second electrode body.

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulator-sealed semiconductor device that eliminates the above-mentioned drawbacks and prevents electrical short circuits due to drooping of thin lead wires.

Means for Solving the Problems The insulator-sealed semiconductor device of the present invention includes a first electrode body, a second electrode body, and a lead between the first electrode body and the second electrode body. A third electrode body disposed as part of the frame, a thin lead wire connecting the first electrode body and the second electrode body across the third electrode body, and a thin lead wire connecting the first electrode body and the second electrode body across the third electrode body; and a chip-like member fixed to the main surface. At the position where the thin lead wire and the third electrode body intersect, the main surface of the chip-like member is located between the thin lead wire and the third electrode body.

The chip-shaped member includes a silicon layer, an insulating layer formed on the silicon layer and forming a main surface as a silicon oxide film, and a metal layer attached to the silicon layer and fixed to the third electrode body.

Function: The chip-like member can be formed by oxidizing and nickel plating or soldering a silicon chip, and can be fixed to the third electrode body immediately below the thin lead wire in the same process as the process of fixing the semiconductor chip to the lead frame. Therefore, even if the number of chip-like members increases, the existing process can be used as is, making it easy to manufacture an insulator-sealed semiconductor device.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. Incidentally, the same parts as those in the conventional example shown in FIG. 4 are given the same numbers, and the explanation will be omitted.

First, as is clear from FIG. 1, the difference between the embodiment of the present invention and the conventional example is that a chip-like member 6 is placed on the wiring electrode body 3, and a thin lead wire is placed above the chip-like member 6. 5 connects the power transistor chip 4 and the wiring electrode body 2. In this case, the emitter electrode of the power transistor chip 4 is the first electrode body, the wiring electrode body 2 is the second electrode body, and the wiring electrode body 3 is the third electrode body. The chip-like member 6 shown in FIG. 1 is a silicon chip, and this silicon chip consists of a silicon layer 6a and an insulating layer 6b formed as a silicon oxide film on the upper surface of the silicon layer 6a.
and a metal layer 6 formed on the lower surface of the silicon layer 6a.
c (nickel layer). This nickel layer is fixed to the wiring electrode body 3 with solder 7 (FIG. 2) or the like.

The silicon oxide film forming the insulating layer 6b can be easily formed by thermal oxidation of a silicon wafer by sharing the process of forming silicon oxide films for other semiconductor chips. Therefore, the insulating layer 6b can be formed without increasing new and different processes.
An oxide film with a thickness of 6000 Å to 1 μm can provide sufficient dielectric strength. Similarly, the nickel layer can be easily formed by nickel plating by sharing the electrode forming process of other semiconductor chips. Therefore, in a series of die bonding processes for fixing the power transistor chip to the support electrode body, the chip-like member 6 can be fixed to the wiring electrode body with solder (not shown), so that it is possible to bond the chip-like member 6 to the wiring electrode body with solder (not shown). They can be treated equally.

The insulator-sealed semiconductor device according to the present invention can be applied to various semiconductor devices. For example, the embodiment shown in FIG. 1 can be applied to the resin-sealed composite IC shown in FIG. This resin-sealed composite IC consists of an electrode body 10 formed from a lead frame and a resin seal 14 that covers the electrode body 10. Electrode body 10
has 15 external leads 11, wiring electrode bodies 12 following each of the external leads 11, and a supporting electrode body 13 which is a large area portion of a particular wiring electrode body 12. As shown in the figure, a monolithic IC chip 15 is fixed to one of the supporting electrode bodies 13 in the electrode body 10.
A power transistor chip 4 is fixed to the other support electrode body 13. A chip-shaped member 6 is fixed onto the two wiring electrode bodies 12. In FIG. 3, the chip-like member 6 is shaded for clarity. A thin lead wire 5 suspended above the chip-like member 6 connects the emitter electrode of the power transistor chip 4 and the wiring electrode body 12.
At this time, the lead thin wire 5 is not connected to the wiring electrode body 1.
2 is connected across one line. However, a chip-like member 6 is fixed to the unconnected wiring electrode body 12 directly below the lead thin wire 5, which prevents contact between the unconnected wiring electrode body 12 and the lead thin wire 5, and Multiple wiring between the body 12 and the thin lead wire 5 can be realized satisfactorily.

Each of the two thin lead wires 5 is substantially orthogonal to the end of the chip-like member 6 when viewed from above, and passes approximately near the center line of the upper surface of the chip-like member 6. In an actual insulator-sealed composite IC, the thin lead wire 5 may float above the chip-like member 6 without contacting it, but it may also come into contact with the chip-like member 6. As described above, in this embodiment, the first
By placing the chip-like member 6 on the wiring electrode body 3 as shown in the figure, it is possible to completely prevent an electrical short circuit accident between the thin lead wire 5 and the wiring electrode body 3. In other words, even if the thin lead wire 5 hangs down significantly due to its own weight or resin injection pressure, the chip-like member 6 supports the thin lead wire 5 and prevents it from coming into contact with the wiring electrode body. This is particularly effective when the second bonding part is located near the resin injection hole 16 as shown in FIG. In addition, the insulating layer 6 of the chip-shaped member 6
Since layer b is formed of a silicon oxide film having sufficient dielectric strength, the upper surface of insulating layer 6b and wiring electrode body 3 are completely insulated. Therefore, even if the thin lead wire 5 hangs down significantly for some reason and comes into contact with the insulating layer 6b of the chip-shaped member 6, the thin lead wire 5 and the wiring electrode body 3 are maintained in an insulated state, so that electrical Short circuit accidents can be avoided. Moreover, unlike an insulator formed by coating, the chip-like member 6 has a height sufficient to prevent contact with the wiring electrode body 3, so that the contact of the thin lead wire 5 with the wiring electrode body 3 is effectively prevented. It is possible to prevent the supporting electrode body 1 from
At the same time, the effect of preventing contact with other objects can also be obtained.

Chip-like member 6 is power transistor chip 4
And since it can be fixed to the wiring electrode body 12 in the same die bonding process as the monolithic IC chip 15, there is no need to add a new and different process to fix the chip-shaped member 6 on the lead frame. In addition, in FIG. 3, the wiring electrode body 1 is shown in the portion where the chip-shaped member 6, the power transistor chip 4, and the monolithic IC chip 15 are fixed.
2 and the supporting electrode body 13 by printing cream solder (paste-like solder) in advance, and temporarily bond the chip-shaped member 6, power transistor chip 4, and monolithic IC chip 15 with the adhesive force of the cream solder. These are then fixed through a process of heating and melting the solder (reflow process). Incidentally, an example of the size of the chip-like member 6 is 2.3 mm long x 1.5 mm wide x 0.3 to 0.5 mm thick.
Power transistor chip 4 is 1.6mm long x 1.6mm wide
It will be understood that since the size is 0.3 mm x 0.3 mm, the chip-shaped member 6 can be handled in the same manner as a semiconductor chip.

Here, the side surfaces of the chip may be covered with a glass film. This allows more complete insulation to be obtained.

The above-described embodiments of the present invention can be modified in various ways. For example, in the above embodiment, the structure of the chip-like member 6 is illustrated as a silicon wafer, but the chip-like member 6 of the present invention is not limited to this structure. However, if a silicon wafer is used as in the above embodiment, the chip-like member can be formed without adding another process, which is advantageous in terms of production efficiency.

Further, the present invention is not limited to the case where the thin lead wire connects a semiconductor chip such as a power transistor chip and a wiring electrode body. That is, the first electrode body and the second electrode body are electrodes formed on a lead frame, a circuit board fixed to the lead frame, and an electronic element such as a semiconductor chip fixed on a lead frame or printed circuit board. Various electrodes such as electrodes are targeted. Furthermore, the location where the chip-like member 6 is fixed is not limited to the wiring electrode body.

Effects of the invention In the insulator-sealed semiconductor device of the present invention, the chip-like member is mounted on the third electrode body directly below the thin lead wire, so even if the thin lead wire droops considerably, the chip-like member remains a lead. Since the thin wire is supported, electrical short circuit accidents caused by contact between the thin lead wire and the third electrode body can be completely avoided. In addition, the chip-like member can be placed on the third electrode body in the same process as the fixing of the semiconductor chip, and in this case, electrical short circuit accidents can be avoided without substantially reducing production efficiency. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an insulator-sealed semiconductor device according to the present invention, FIG. 2 is an enlarged cross-sectional view of a chip-like member, and FIG. 3 is a resin-sealed semiconductor device using the embodiment of FIG. FIG. 4 is a perspective view showing a conventional example, FIG. 5 is a process diagram showing a method for connecting thin lead wires using the nail head bonding method, and FIG. 5A is a diagram showing the tip of the thin lead wire. Figure 5B is a state where the first bonding part is formed on the first electrode body, Figure 5C is a state where the capillary is moved, and Figure 5D is a state where the ball is formed on the second electrode body. state of forming the second bonding part, fifth
Figure E shows the state in which the thin lead wire is cut. 1... Supporting electrode body, 2... Wiring electrode body (first electrode body), 3... Wiring electrode body (third electrode body), 4
...Power transistor chip (emitter electrode is the first electrode body), 6... Chip-shaped member, 6a...
Silicon layer, 6b...insulating layer, 6c...metal layer.

Claims (1)

[Claims for Utility Model Registration] A first electrode body, a second electrode body, and a third electrode body disposed as part of a lead frame between the first electrode body and the second electrode body. an electrode body, a thin lead wire connecting the first electrode body and the second electrode body across the third electrode body, and a chip-shaped wire fixed to one main surface of the third electrode body. an insulator-sealed type member, wherein the main surface of the chip-like member is located between the thin lead wire and the third electrode body at a position where the thin lead wire and the third electrode body intersect. In the semiconductor device, the chip-shaped member includes a silicon layer, an insulating layer formed on the silicon layer and forming a main surface as a silicon oxide film, and attached to the silicon layer and fixed to the third electrode body. What is claimed is: 1. An insulator-sealed semiconductor device comprising: a metal layer;