JPH0525237Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a resin-sealed semiconductor device having a structure in which a plurality of semiconductor elements are electrically connected via thin lead wires.

Conventional technology and issues to be solved Today, there is an increasing demand for high-density packaging in power semiconductor devices, and multiple semiconductor elements are integrated into one.
It is desired to realize a power semiconductor device having a structure packaged with two insulator sealing bodies. Therefore, the present inventor attempted to manufacture a power semiconductor device having the above structure using a lead frame having a plurality of support plates and a corresponding number of external leads. However, when the number of semiconductor elements exceeds three, the wiring becomes extremely complicated, and the length of thin lead wires connecting the semiconductor elements increases, resulting in problems such as short-circuit accidents and the like.

Therefore, an object of the present invention is to provide a resin-sealed semiconductor device having a novel structure and having a plurality of semiconductor elements that can solve the above-mentioned problems.

Means for Solving the Problems The resin-sealed semiconductor device of the present invention includes a first support plate on which a first semiconductor device is placed, and a second support plate on which a second semiconductor element is placed. has. 1st
A wiring electrode body on which a relay member is placed is interposed between the support plate and the second support plate. The relay member has an electrode body electrically insulated from the wiring electrode body. The electrode body of the relay member and the electrode body formed on the first semiconductor element are electrically connected via the first thin lead wire. The electrode body of the relay member and the electrode body formed on the second semiconductor element are electrically connected via a second thin lead wire. The wiring electrode body is electrically connected to another electrode body formed on the first semiconductor element via a third thin lead wire, and is arranged further away from the first semiconductor element than the second semiconductor element. and extends to the vicinity of the third semiconductor element. Furthermore, the wiring electrode body is electrically connected to the electrode body formed on the third semiconductor element via a fourth thin lead wire.

One of the first semiconductor device and the second semiconductor device is a monolithic IC chip, and the other is a power transistor chip.

The relay member includes an insulating layer made of a resin piece, a first metal layer formed on one main surface of the insulating layer, and a second metal layer formed on the other main surface of the insulating layer. , the first metal layer serves as an electrode body, and the second metal layer is fixed to one main surface of the wiring electrode body via solder.

The relay member includes a silicon piece, an insulating layer made of an oxide film formed on one main surface of the silicon piece, a first metal layer formed on the surface of the insulating layer, and a first metal layer formed on the other main surface of the silicon piece. a second metal layer formed thereon.

Effect According to the present invention, the thin lead wire connecting the electrode body of the first semiconductor element and the electrode body of the second semiconductor element is divided into the first thin lead wire and the second thin lead wire. Each other end of the second thin lead wire is connected to the relay member. This relay member is the first and second relay member.
The semiconductor device is attached to a wiring electrode body disposed between the first and second support plates on which the semiconductor device is mounted. Therefore, the connection distance between the first and second thin lead wires can be shortened, and drooping of the thin lead wires can be suppressed. Further, the third semiconductor element, which is disposed further away from the first semiconductor element than the second semiconductor element, is connected to the first semiconductor element via the fourth thin lead wire, the wiring electrode body, and the third thin lead wire. electrically connected to. The wiring electrode body is electrically insulated from the first and second thin lead wires and is multi-wired with the first and second leads. Therefore, complex three-dimensional wiring becomes possible.

Embodiment Hereinafter, as an embodiment of the present invention, a resin-sealed composite IC for electric power will be described with reference to FIGS. 1 to 3.

The power resin-sealed composite IC of this embodiment includes a lead frame 1 and a power transistor chip 2a.
2d, a monolithic IC chip 3, a large number of thin lead wires 4, relay members 10 and 20, and a resin molding body 6. The lead frame 1 includes a plurality of external lead parts 7a to 7p, wiring electrode body parts 8a to 8p that follow these, and support plates 9a and 9 that follow these.
It has c, 9h, 9m, and 9p. Note that the lower surfaces of the external lead portions 7a to 7p, the wiring electrode body portions 8a to 8p, and the support plates 9a, 9c, 9h, 9m, and 9p are on the same plane.

On the upper surfaces of the support plates 9a, 9c, 9m, 9p are power transistor chips 2a, 2b, 2, respectively.
A monolithic IC chip 3 is placed on the upper surface of the support plate 9h.
Power transistor chips 2a, 2b, 2c, 2
There are multiple electrodes (bonding pads) on the top surface of d.
A large number of bonding pads are also formed on the upper surface of the monolithic IC chip 3.

Relay members 10 and 20 are placed on the upper surfaces of the wiring electrode body parts 8d and 8l, respectively. Relay member 1
0 is an insulating layer 11 and an insulating layer 1 as shown in FIG.
1 and a second conductor layer 13 formed on the other main surface of the insulating layer 11. Further, the relay member 20 also includes an insulating layer, a first conductor layer formed on one main surface of the insulating layer, and a second conductor layer formed on the other main surface of the insulating layer. The insulating layer is formed of a polyimide or epoxy resin plate (a resin plate in which a woven glass fiber cloth is enclosed as an aggregate). The first and second conductor layers have a three-layer structure consisting of a copper layer, a nickel layer, and a silver layer in order from the insulating layer side. The copper layer has excellent adhesion to the resin plate forming the insulating layer, and the silver layer enables good connection with the thin lead wire. Furthermore, since the nickel layer is formed hard, it does not absorb ultrasonic vibrations during wire bonding, and is therefore effective in performing good wire bonding. The relay members 10 and 20 are the second
The conductor layers are fixed to the wiring electrode body portions 8d and 8l via solder (not shown). The relay members 10, 20 are fixed onto the wiring electrode bodies 8d, 8l by the same process (die bonding) within the process of fixing the monolithic IC chip 3 to the support plate 9h. The lead thin wire 4 is a thin wire made of gold (Au) or a gold alloy and has a diameter of about 30 μm. The thin lead wire 4 connects the power transistor chips 2a to 2.
Nail head bonding and relay member 1 are used for electrodes d and monolithic IC chip electrodes.
0, 20 and wiring electrode body parts 8b, 8d, 8e, 8
Static bonding is applied to f, 8g, 8j, 8k, 8l, and 8n.

Next, a method for connecting the thin lead wires 4 will be described with reference to FIG. 3, taking as an example a method for connecting the thin lead wires between the monolithic IC chip 3 and the relay member 10.

First, as shown in FIG. 3A, the thin lead wire 4 is sent out from the center hole 51 of the pipe-shaped capillary 50 of the wire bonder, and a ball is formed at the tip of the thin lead wire 4 using an electric spark, hydrogen flame, or the like. The diameter of the ball is about 2 to 3 times the diameter of the thin lead wire 4.

Next, as shown in Figure 3B, the monolithic
First bonding is performed by pressing the ball against the electrode of the IC chip 3 with the tip of the capillary 50. At this time, the electrodes of the monolithic IC chip should be kept at a temperature of 200 to 250℃.
pre-heated. Furthermore, ultrasonic vibration is applied to the capillary 50 in the direction indicated by an arrow 52 perpendicular to the connecting direction of the thin lead wire 4 . As a result, a first bonding portion (nail head bonding portion) 4a is formed in which the thin lead wire 4 is connected to the electrode of the monolithic IC chip in the shape of a nail head.

Next, as shown in Figure 3C, the capillary 5
The capillary 50 is moved toward the relay member 10 while letting out the thin lead wire 4 by raising the wire 0 and drawing it around widely.

Thereafter, as shown in FIG. 3D, the relay member 10
A second bonding is performed on the first conductor layer 12 of. That is, the first conductor layer 12 has a thickness of 200
The capillary 50 is preheated to ~250°C, and the same ultrasonic vibrations as described above are applied to the capillary 50. In this state, by pressing the lead thin wire 4 in the radial direction against the first conductor layer 12, the lead thin wire 4 and the first
is connected to the conductor layer 12 to form a second bonding section (stanch bonding section) 4b. Note that the steps shown in FIGS. 3B and 3D 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, as shown in Figure 3E, connect capillary 5.
0 to a certain height, the capillary 50 is further raised while holding the thin lead wire 4 with a clamp, and the thin lead wire 4 is cut. As shown in FIG. 3D, on the first bonding side, the angle α of the thin lead wire 4 with respect to the electrode of the monolithic IC chip 3 is approximately a right angle, and the distance between the thin lead wire 4 and the thin lead wire 4 that straddles the top becomes long. On the other hand, on the second bonding side, the angle θ of the thin lead wire 4 with respect to the first conductor layer 12 is an acute angle, and the distance between the thin lead wire 4 and the thin lead wire 4 spanning over the thin lead wire 4 is shortened.

The power resin-sealed composite IC of this embodiment includes relay members 10 and 20 and a power transistor chip 2.
Since elements a to 2d are arranged symmetrically with respect to the monolithic IC chip 3, only the left side of the monolithic IC chip 3 in FIG. 1 will be described.

In FIG. 1, a monolithic IC chip 3 corresponds to the first semiconductor device of the present invention, and power transistor chips 2a and 2b correspond to the third and second semiconductor devices of the present invention, respectively. Further, the thin lead wire 4 connecting the monolithic IC chip 3 and the relay member 10 corresponds to the first thin lead wire of the present invention. The thin lead wire 5 connecting the relay member 10 and the power transistor chip 2b corresponds to the second thin lead wire of the present invention. Thin lead wire 1 connecting monolithic IC chip 3 and wiring electrode body 8d
4 corresponds to the third thin lead wire of the present invention. The thin lead wire 15 connecting the wiring electrode body portion 8d and the power transistor chip 2a corresponds to the fourth thin lead wire of the present invention. By connecting via the relay member 10, each connection distance between the first thin lead wire and the second thin lead wire can be shortened. Therefore, drastic drooping of the thin lead wire can be prevented. Therefore, the thin lead wires do not droop during molding of the sealing resin.
No electrical short circuits occur. Furthermore, since the first conductor layer 12 and the second conductor layer 13 of the relay member 10 are electrically insulated by the insulating layer 11, the wiring electrode body 8d to which the relay member 10 is fixed is connected to the first and second conductor layers 13 and 13. Multiple wiring (crossover wiring) is possible with the second thin lead wire. This expands the degree of freedom in wiring, making it possible to meet complex wiring requirements.

Further, since the relay member 10 can be fixed to the wiring electrode body 8d in the same die bonding process as the power transistor chips 2a, 2b or the monolithic IC chip 3, it is necessary to perform a new and different process to arrange the relay member 10. There isn't. Note that the relay member 10, power transistor chips 2a, 2b
Cream solder (paste-like solder) is printed in advance on the wiring electrode body and supporting electrode body of the portion to which the monolithic IC chip 3 is fixed, and then the relay member 10 and the power transistor chips 2a, 2b are attached. The monolithic IC chip 3 is temporarily fixed using the adhesive force of the cream solder, and is then fixed through a process of heating to melt the solder (reflow process).

In addition, as an example, the size of the relay member 10 is
2.3mm x width 1.5mm x thickness 0.3 to 0.5mm, and monolithic IC chip 3 is 1.6mm long x 1.6mm wide x 0.3mm thick.
Therefore, it will be understood that the relay member 10 can be handled in the same manner as a semiconductor chip. In addition, since the thin lead wire is connected via the relay member 10, the electrode of the power transistor chip 2b and the monolithic wire are connected via the relay member 10.
A first bonding portion can be formed on both electrodes of the IC chip 3. Conventionally, it has been practically difficult to form a second bonding portion on the electrode of the monolithic IC chip 3 or the electrode of the power transistor chip 2b. That is, since the shape of the second bonding part is longer in the connection direction than the first bonding part, the bonding pad must be formed longer to match the shape of the bonding part. Therefore, there is a drawback that the area on the chip is greatly restricted by the bonding pad. As described above, it is practically impossible to form a second bonding portion on the electrode of a semiconductor chip, and it has been difficult to connect semiconductor chips with each other using thin lead wires. However, in this embodiment, since the first bonding portions can be formed on both electrodes, it is possible to connect semiconductor chips to each other.

Furthermore, as is clear from FIG. 3D, when forming the second bonding part, the capillary 50 may come into contact with the electrode formed on the semiconductor chip. Semiconductor chips are thin and have low strength, so if a capillary comes into contact with an electrode, the electrode or the semiconductor chip itself may be damaged. However, when forming the first bonding part, as shown in FIG. 3C, the ball pressed onto the electrode by the capillary 50 spreads widely over the electrode, so the capillary 50 does not come into contact with the electrode. Therefore, there is an advantage that bonding can be performed without damaging the electrodes or the semiconductor chip.

Incidentally, a similar effect can be obtained on the right side of the monolithic IC chip 3.

Further, in this embodiment, since the planar shape of the lower surface of the lead frame is not impaired, the bonding work does not become complicated as in the conventional example.

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

For example, relay members 10, 20 can be made from silicon wafers. That is, an oxide film is formed by thermal oxidation on one main surface of the silicon wafer (the side where the thin lead wire is connected), an aluminum electrode is formed through the silicon oxide film, and an aluminum electrode is formed on the other main surface (the side that is fixed to the lead frame). Forms a nickel electrode by plating. An oxide film with a thickness of 6000 Å to 1 μm can provide sufficient dielectric strength. Next, the silicon wafer is divided into predetermined small chips. Here, the side surfaces of the chip may be covered with a glass film. Note that the above steps can be used in common with other semiconductor chip manufacturing steps.

Here, since the angle θ of the first thin lead wire and the second thin lead wire with respect to the aluminum electrode (conductor layer) is small, when the thin lead wire hangs down, the thin lead wire comes into contact with the side surface of the relay member, causing an electrical short circuit accident. There is a risk of The aforementioned glass film is effective in preventing the occurrence of electrical short circuit accidents. Further, after forming the first thin lead wire and the second thin lead wire, both second ponding portions and their surroundings may be coated with a polyimide resin or the like. This allows the thin lead wire to be fixed at a constant height. in this way,
When a protective resin is attached to the second bonding area and its surroundings, it improves insulation properties and fixes the thin lead wire.
This is preferable in this respect. Since the above-mentioned coating with the protective resin can be performed using the same material and the same process as the coating on the semiconductor chip, there is no need to add a new and different process for the coating.

The relay members 10 and 20 are metal pieces, and the metal pieces may be fixed onto a lead frame using an insulating resin. For example, relay members 10, 2
0 is a metal piece such as a copper material coated with nickel. The portions of the nickel coating to be wire bonded are further plated with silver. in this case,
The relay member 10 is made of an insulating adhesive such as epoxy resin.
By fixing 20 to the wiring electrode body 8d, electrical insulation is achieved between the main surfaces of the relay members 10 and 20 and the lead frame by the adhesive.

In addition, it is monolithic with only one thin lead wire.
The electrodes of the IC chip and the electrodes of the power transistor chip may be connected. That is, a thin lead wire whose one end is connected to the electrode of the monolithic IC chip may be connected to the relay member at least once, and then the other end may be connected to the electrode of the power transistor chip. In this case, the lead wire connected to one side of the relay member is the first lead wire, and the lead wire connected to the other side is the second lead wire.

In the embodiment described above, the relay member 10 has the first conductor layer 12 and the second conductor layer 13, but the second conductor layer 13 may not be formed. In this case, the insulating layer 10 can be directly fixed to the lead frame with an epoxy resin adhesive or the like.

Effects of the Invention In the present invention, since the lead wires are connected via the relay member, it is possible to prevent the thin lead wires from drooping significantly, and defects due to electrical short circuits do not occur. Further, by providing a relay member, cross wiring becomes possible, and complex wiring can be formed with a good yield.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a resin-sealed composite IC showing an embodiment of the resin-sealed semiconductor device of the present invention;
The figure is a partial perspective view of FIG. 1, and FIG. 3 is a process diagram showing a method of connecting thin lead wires by the nail head bonding method. Figure 3B shows the state in which the bonding part is formed, Figure 3C shows the state in which the capillary is moved, Figure 3D shows the state in which the second bonding part is formed, and Figure 3E shows the state in which the thin lead wire is cut. . 3... Monolithic IC chip (first semiconductor element), 2a... Power transistor chip (third semiconductor element), 2b... Power transistor chip (second semiconductor element), 9h... First support plate , 9c... second support plate, 9a... third support plate, 10, 20... relay member, 8d, 8l...
Wiring electrode body portion (wiring electrode body), 12...first conductor layer (electrode body), 4...first lead thin wire, 5...
...Second thin lead wire, 14...Third thin lead wire, 15...Fourth thin lead wire.

Claims (1)

[Claims for Utility Model Registration] (1) A first support plate on which a first semiconductor element is placed and a second support plate on which a second semiconductor element is placed; A wiring electrode body on which a relay member is placed is interposed between the support plate and the second support plate, and the relay member has an electrode body electrically insulated from the wiring electrode body. , the electrode body of the relay member and the electrode body formed on the first semiconductor element are electrically connected via a first thin lead wire, and the electrode body of the relay member and the electrode body formed on the second semiconductor element The electrode body formed on the element is electrically connected via a second thin lead wire, and the wiring electrode body is connected to another electrode body formed on the first semiconductor element and the third thin lead wire. and extends to the vicinity of a third semiconductor element that is electrically connected to the first semiconductor element via the second semiconductor element and is arranged further away from the first semiconductor element than the second semiconductor element, and the third semiconductor element 1. A resin-sealed semiconductor device, characterized in that the device is electrically connected to an electrode body formed in the semiconductor device through a fourth thin lead wire. (2) The resin-sealed semiconductor device according to claim 1, wherein one of the first semiconductor element and the second semiconductor element is a monolithic IC chip and the other is a power transistor chip. (3) The relay member includes an insulating layer made of a resin piece;
a first metal layer formed on one main surface of the insulating layer; and a second metal layer formed on the other main surface of the insulating layer, and the first metal layer is connected to the electrode. 2. The resin-sealed semiconductor device according to claim 1, wherein the second metal layer is fixed to one main surface of the wiring electrode body via solder. (4) The relay member includes a silicon piece, an insulating layer made of an oxide film formed on one main surface of the silicon piece, a first metal layer formed on the surface of the insulating layer, and the silicon piece. a second metal layer formed on the other main surface of the piece, the first metal layer serving as the electrode body, and the second metal layer being fixed to the wiring electrode body via solder. A resin-sealed semiconductor device according to claim 1, which is a utility model registered as claimed in claim 1.