JPS63215058A - Insulator seal type semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a lead thin wire from coming into contact with an electrode, by arranging, under the lead thin wire, a retaining thin wire preventing the lead thin wire from hanging down. CONSTITUTION:When a first electrode 19 formed on a retaining electrode body and a second electrode 1b are connected by a lead thin wire 23, the second electrode 1b is provided with a retaining thin wire 40, which retains the lead thin wire. Thereby, the lead thin wire 23 can be prevented from hanging down by virtue of the retaining thin wire, so that the lead thin wire 23 can be prevented from generating the short circuit with another electrode 3b arranged between the first electrode 19 and the second electrode 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulator-sealed semiconductor device having a structure that prevents frosting of a thin lead wire connecting two electrode bodies.

Calamity of the 31st J! l is a conventional 4# fat-sealed hybrid IC
The top view of the figure is shown. This hybrid IC includes 15 external electrode bodies 18 to 15a, wiring electrode bodies 1b to 15b provided as extensions of the external electrode bodies 18 to 15a, and wiring electrode bodies 2b, 4b, 9b, 13b, and 15b. Support electrode bodies 2c, 4c, 9c, 1 provided as subsequent large area parts
It has electrode bodies 1 to 15 consisting of electrode bodies 3c and 15c. Wiring electrode bodies 1b to 15b and supporting electrode bodies 2c, 4c, 9
c, 13c and 15c are sealed with a resin sealing body 16 indicated by a dotted line, and external electrode bodies 1a to L5Q are sealed with a resin sealing body 1B.
is derived outward from. The external electrode bodies 18 to 1.5a are
They are arranged in parallel at an inch pitch (2.54 mm+), and have a shape that is wide at the outlet side and narrow at the tip. The monolithic IC chip 17 is mounted on the supporting electrode body 9c.
It is fixed with 8n solder (not shown). Power transistor chips 18 to 21 are fixed to the supporting electrode bodies 2c, 4c, 13c, and 15c using the same Pb-8n solder (not shown). Although not shown, monolithic I
A large number of electrodes (ponding pads) made of aluminum are formed on the upper surface of the C chip 17. Also,
The monolithic IC chip 17 is covered with a protective resin made of silicone rubber, but is not shown. Although not shown, emitter electrodes and base electrodes made of aluminum are formed on the upper surfaces of the power transistor chips 18 to 21, and collector electrodes made of nickel are formed entirely on the lower surfaces. power transistor chip 18
21 are also coated with a protective resin made of silicone rubber (not shown).

The emitter electrodes of each of the power transistor chips 18 to 21 are connected to the wiring electrode body 1b by two lead wires 22 to 25, respectively, in order to ensure a sufficient voltage. In addition, power transistor chips 18 to 21
Each of the base electrodes has one lead wire 26.
~29, wiring electrode bodies 3b, 5b, 12b and 14b
connected to.

The ten 'IfL poles on the monolithic IC chip 17 are connected to the wiring electrode bodies 3b, 5b to 8b, 10b to 12b, 14b by one lead 111630 to 39, respectively.
and connected to the supporting electrode body 9c. Lead thin wire 22-3
9 is a thin wire made of gold (Au) or a gold alloy and having a diameter of about 30 μm. V that makes up the lead frame
lL44! The bodies 1-15 are press-formed from nickel-coated steel. However, power transistor chip 18
~The part where 21 is fixed.

The parts to which the thin lead wires 22 to 39 are connected are partially plated with silver to form a three-layer structure of copper-nickel-silver.

Next, a method for connecting thin lead wires will be explained with reference to FIG.

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

Next, as shown in FIG. 5CB), the ball 53 is pressed against the first electrode body 54 with the tip of the capillary 50. At this time, the first electrode body 54 is heated to 200 to 250°C. Furthermore, ultrasonic vibration is applied to the capillary 50 in the direction indicated by an arrow 55 perpendicular to the direction in which the thin wire 52 is connected. As a result, the first electrode body 54 and the thin wire 52
are connected, and a first bonding portion 52a is formed by the nail head bonding method.

Subsequently, as shown in FIG. 5(C), the capillary 50
The capillary 50 is raised toward the second electrode body 56 while drawing out the thin wire 52.
move.

Thereafter, as shown in FIG. 5(D), the second electrode body 56
Stain inch bonding. That is, the second electrode body 5
6 is preheated to 200 to 250° C. as described above, and the same ultrasonic vibration as described above is applied to the capillary 5o. In this state, by suppressing the thin wire 52 in the radial direction with respect to the second electrode body 56, the thin 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. 5(B) and 5(D) may be performed by a thermocompression bonding method using only heating of the electrode body, an ultrasonic method using only heating using ultrasonic vibration, or the like.

Finally, as shown in FIG. 5(E), the thin wire 52 is pulled upward while the capillary 50 is pressed against the second electrode body 56 to cut the thin wire 52. In a narrow sense, the connection to the first electrode body (first bonding) is called nail head bonding, and the connection to the second electrode body (second bonding) is called stitch bonding, but here they are collectively referred to. The nail head bonding method is used.

As shown in FIG. 4 and FIG. 5(D), on the first bond ink side, the angle α of the thin wire 52 with respect to the first electrode body is almost a right angle, and the angle α between the thin wire 52 that straddles above and the first electrode body is almost a right angle. The distance becomes longer. On the other hand, on the second bonding side, the angle θ of the thin wire 52 with respect to the second electrode body is an acute angle, and the distance between the thin wire 52 that straddles above and the second electrode body is shortened.

In the past, when the thin lead wire flew down, it came into contact with the wiring electrode body and the support electrode body, causing a short circuit. That is, as illustrated in FIG. 4, the lead thin l1A23 is connected across the wiring electrode body 3b. Due to the demand for higher integration of semiconductor devices, wiring tends to become more complex. For this reason, I often have to make a connection that spans the wiring electrode body.

By the way, the wiring electrode body 3b formed between the supporting electrode body 4c, which is the first electrode body, and the wiring electrode body 1b, which is the second electrode body, is a non-connecting wiring body with respect to the lead thin wire 23. It has become. For this reason, the thin lead wires 23 are connected in a large arc during wire bonding so as to maintain as much distance as possible between the thin lead wires 23 and the wiring 111c44 body 3b. The thin lead wire 23 is connected to the power transistor chip 19 at the first bonding part and to the wiring electrode body 1b at the second bonding part by the nail head bonding method described in s-+W. Further, the first bonding portion is located higher than the second bonding portion by approximately the thickness of the power transistor 19. Therefore, the distance between the wiring electrode body 3b and the thin lead wire 23 on the side of the supporting electrode body 4c becomes long, but the distance from the thin lead wire 23 on the side of the wiring electrode body lb becomes short.

The normally used thin 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, when connecting a first electrode body and a second electrode body. Fine lead wire made of gold.

Loop sagging may occur due to resin injection pressure or self-weight during transfer molding. Normally, for a thin gold lead wire with a diameter of 25 to 30 μm, the connection distance is limited to 31 mm. Connection distance is 3+
If it exceeds mm, loop sagging 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 becomes even shorter. In order to shorten the connection distance 111L, it is possible to reduce the width of the unconnected wiring body. However, due to restrictions such as weakening of the mechanical strength of the lead frame, it is not possible to make the lead frame very thin. Therefore, in the example of FIG. 4, the connection distance 11L is 3.3 mm.

Therefore, an accident occurs in which the fine lead wire 23 comes into contact with the wiring electrode body 1b side of the wiring electrode body 3b, which is one of the causes of lowering the manufacturing yield.

As a measure to prevent short-circuit defects due to loop sagging, for example, a method of covering unconnected wiring bodies with an insulating material can be considered. However, it creates an electrical point that requires an additional manufacturing step of coating with an insulating material.

Another method to prevent loop sag is to increase the strength by increasing the diameter of the thin lead wire, but it is not suitable for practical use because gold is expensive. It is also possible to consider a method in which step processing is performed to raise at least one of the electrode bodies by a certain height.

However, this method also has the drawback that it requires an additional process of step machining, and since the lead frame has steps, handling of the lead frame is complicated, and the support structure of the lead frame during bonding becomes complicated. be.

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 the thin lead wires from flying down.

In the insulator-sealed semiconductor device of the present invention, a first electrode body and a second electrode body are connected by a thin lead wire, and the thin lead wire is shorter than the thin lead wire. It has a structure in which a thin support wire for preventing flying down is provided below the thin lead wire.

■ The thin support wire provided below the thin lead wire can prevent the thin lead wire from drooping.

Embodiments of the present invention will now be described with reference to FIGS. 1 and 2. FIG. In these drawings, except for the provision of thin support lines,
Figures 3 and 41)! Everything is the same as the conventional example shown in FIG.

FIG. 2 is a plan view of a hybrid IC showing an embodiment of the insulator-sealed semiconductor device of the present invention in which thin support wires are formed. The support cylinder l1jI40 connects the wiring w below each of the thin lead wires 22 to 25 that connect the wiring electrode body 1b and the emitter electrodes of the power transistor chips 18 to 21.
It is connected to the i-frame body 1b. FIG. 1 is an enlarged perspective view showing the vicinity of the thin lead wire 23 in FIG. 2. FIG. Two leads @@23 are connected between the emitter electrode of the power transistor chip 19 and the wiring electrode body 1b, straddling the upper part of the wiring 'I41 pole body 3b to which the thin lead wires are not connected. At the bottom, both ends of the thin support wire 400 are connected to the wiring electrode body 1b. In this case, the emitter electrodes of power 1 to transistor chip 19 are the first electrode body, and the wiring electrode body 1b is.

The electrode body 3b becomes the second electrode body, and the electrode IiA electrode and the pole body 3b become the third electrode body. The thin lead wire 23 and the thin support wire 40.

When viewed from above, they intersect at nearly right angles.

The lead thin M23 is connected by the above-described nail head bonding method, and has a first bonding part 23a connected to the emitter electrode of the power transistor chip 19 and a second bonding part 23b connected to the electrode body 1b of the wiring Im. The supporting thin wire 40 is adjacent to the second bonding portion 23b of the lead thin wire 23 and is connected to the wiring electrode body 1.
connected to b.

The support thin wire 40 is a lead thin wire 23 made of gold or gold alloy.
The first bonding ink portion 40a and the second bonding portion 40b are formed by the same nail head bonding method using a combination of a thermocompression bonding method and an ultrasonic method using the same fine wire and the same wire bonder. That is, the supporting thin wire 4
0 is formed prior to forming the lead wires 22 to 25 during the wire bonding process for forming the lead wires 22 to 39. When viewed in the extending direction of the lead wire 23, the second bonding portion 4 of the two support wires 40
0b are connected in opposite directions. This reduces the width occupied by the thin support wire 40.

The thin lead wire 23 is connected to the emitter electrode of the power transistor chip 19 and the wiring electrode body 1b so as to pass over the thin support wire 40 by a nail head bonding method that uses both a thermocompression method and an ultrasonic method. At this time, first bonding is performed on the emitter electrode of the power transistor chip 19, and second bonding is performed on the wiring electrode body 1b.

The lead wire @23 passes approximately at the apex of the support thin wire 40 or slightly on the second bonding side of the apex. The ribbon thin @23 comes into contact with the thin support wire 40 during one-twist bonding, but it may float slightly away from the thin support wire 40 after resin sealing. Since the support thin wire 40 is shorter than the lead thin wire II&23, it can obtain greater strength against drooping than the lead thin wire 23. When the thin lead wire 23 droops due to resin injection pressure or its own weight, it is supported by the thin support wire 40, so the thin lead wire 23 will not droop significantly. It is possible to prevent contact with the electrode body 3b or the supporting electrode body 4C. The same applies to the thin lead wire 24. In addition, in the lead thin l1A22.25 portion where there is no third electrode body such as a wiring electrode body between the first electrode body and the second electrode body, the support thin wire 40 is connected to the support electrode bodies 2c and 15c. 22.2
5 from coming into contact with each other. Furthermore, in this embodiment, the thin support wire 40 is formed on the second bonding side of the thin lead wires 23 and 24, which is effective in preventing contact between the third electrode body and the thin lead wire on the second bonding side, which is particularly likely to occur. Further, since the lead thin wire 23 and the support thin wire 40 are connected as a series of wire bonding processes, there is no need to add a new process to form the support thin wire 40, and there is almost no reduction in production efficiency.

The above-described embodiments of the invention can be modified in various ways.

For example, it is not necessary to connect a semiconductor chip such as a power transistor chip and a wiring electrode body, and the first electrode body and the second electrode body are both connected to a wiring electrode body (surface of a lead frame).
Therefore, the present invention is effective even when applied to a case where a third electrode body is provided between these.

Furthermore, in the above embodiment, an example was shown in which the supporting thin wire was connected to the second electrode body, but the support wire may be connected to one or both sides or the center of the first electrode body and the second electrode body. A thin line may also be provided. however.

Due to the characteristics of the nail head bonding method, it is rational and effective to provide a thin support wire on the second bonding part side.

When the thin lead wire is a thin wire made of gold or an all-alloy, drooping of the thin lead wire tends to be a problem, but the present invention is effective even if the thin lead wire is a copper wire or the like.

The first electrode body and the second electrode body are electrodes formed on the surface of a lead frame, a circuit board fixed to a lead frame, and an electrode formed on an electronic element such as a semiconductor chip fixed to a lead frame or a printed circuit board. Various electrodes such as electrodes are targeted.

In the present invention, since the thin support wire is formed below the thin lead wire, it is possible to prevent the electrode body and the thin lead wire from coming into contact with each other, which should be in an unconnected state, and to prevent short-circuit accidents. can.

Further, in the present invention, the lead thin wire and the support thin wire can be formed in a series of wire bonding steps using the same thin wire and the same wire bonder. In this case, no special equipment is required to form the support thin wires, different processes such as special processing on the lead frame are not increased, and the number of wire bonding locations is increased. Since ear bonding can be done quickly and easily with an automatic wire bonder, its impact is small, and therefore the objective (short-circuit prevention) can be achieved without substantially reducing production efficiency and very economically. Can be done.

[Brief explanation of the drawing]

111th! 1 and 2 show a hybrid IC which is an embodiment of the present invention, FIG. 1 is an enlarged perspective view of a part of FIG. 2, FIG. 2 is a plan view, and FIG. 3 is a conventional hybrid IC. 4 is an enlarged perspective view of a part of FIG. 3, and FIG. 5 is a process diagram showing a method of connecting thin lead wires by the nail head bonding method. A) is a state in which a ball is formed at the tip of the thin wire sent out from the capillary, and FIG. 5CB) is a state in which the ball is pressed against the first electrode body at the tip of the capillary to form a first bonding part. (C) is a state in which the capillary is moved, FIG. 5 (D) is a state in which a second bonding part is formed on the second electrode body, and FIG. 5 (E) is a state in which the capillary is kept suppressed against the second electrode body. Shows how to cut a thin wire. 1b0. Wiring electrode body (second electrode body), 3b. Wiring electrode body (third electrode body) 4c, , Supporting electrode body. 190. Power transistor chip (emitter electrode is the first electrode body), 230. Fine lead wire, 400.
Support thin wire, patent applicant Sanken Electric Co., Ltd. Figure 1 Figure 4

Claims (6)

[Claims] (1) The first electrode body and the second electrode body are connected by a thin lead wire, and a thin support wire that is shorter than the thin lead wire and prevents the thin lead wire from drooping is provided below the thin lead wire. An insulator-encapsulated semiconductor device. (2) The insulator-sealed semiconductor device according to claim 1, wherein the supporting thin wire is formed by a nail head bonding method using the same thin wire as the lead thin wire and the same wire bonder. (3) The thin lead wire has a first bonding part of the nail head bonding method connected to the first electrode body and a second bonding part of the nail head bonding method connected to the second electrode body, and 2. The insulator-sealed semiconductor device according to claim 2, wherein the thin support wire is provided closer to the second bonding portion than the first bonding portion of the thin lead wire. (4) The insulator-sealed semiconductor device according to claim (3), wherein the thin support wire is connected to a second electrode body. (5) The insulator-sealed semiconductor device according to claim (1), wherein a third electrode body is disposed between the first electrode body and the second electrode body. (6) The first electrode body and the second electrode body are formed on the surface of a lead frame, electrodes formed on a circuit board fixed to the lead frame, or fixed on the lead frame or the circuit board. An insulator-sealed semiconductor device according to claim 1, which is an electrode of an electronic device such as a semiconductor chip.