JP2902993B2 - Hybrid integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hybrid integrated circuit, and more particularly to a hybrid integrated circuit having a power MOSFET.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for variable speeds of induction motors from the viewpoint of energy saving and comfort, and as a means therefor, there has been a great expectation for downsizing and cost reduction of inverter devices. I have. Hereinafter, examples of use of the conventional inverter device will be described with reference to FIGS.

FIG. 4 is a basic configuration diagram of an inverter device, and FIG. 5 is a drive circuit of the inverter device. In FIG. 4, 11
Is an AC power supply, 21 is a rectifier circuit of an AC power supply, 31, 41,
Reference numeral 51 denotes a U-phase connected to the rectifier circuit 21;
And W-phase driving circuits. Each of the phase driving circuits 31, 41, and 51 includes a first base 61, a first power transistor 71, a second base 81, and a second power transistor 91. 101 is a frequency setting unit for setting a frequency, 111 is a control circuit unit that receives a signal from the frequency setting unit 101 and outputs a signal to the first and second base units 60 and 81 of each phase, and 121 is a phase driving circuit 31 , 41, 5
1 is a motor to be connected. FIG. 5 shows a specific example of the drive circuits 31, 41, and 51 in FIG. 4, and the same parts as those in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted. Reference numeral 131 denotes a DC power source serving as a power source in the first base portion 61 and the second base portion 81, and 141 denotes a first power transistor 71 which is turned on and off.
A first base drive unit that performs FF, 151 is a second base drive unit that turns on and off the second power transistor 91, and 161 and 171 are first and second base drive units 14
1, 151 are signal input terminals.

According to the above configuration, if the frequency is set by the frequency setting unit 101 as shown in FIGS.
Reference numeral 1 denotes a power transistor connected to the first and second base portions 61 and 81 of the U, V and W phase driving circuits 31, 41 and 51 at a phase interval of 120 degrees in electrical angle based on the setting signal. A signal for turning on and off 71 and 91 alternately is output. That is, the first and second base units 61 and 81 receive signals at the signal input terminals 161 and 171 of the first and second base drive units 141 and 151, respectively, and
1 turns on the power transistors 71 and 91 alternately.
When the motor 121 is turned off, the DC voltage supplied by the rectifier circuit 21 is equivalently converted into three-phase AC, and the motor 121 is operated.

The inverter circuit using the power transistor described above is mainly used for driving a low-speed motor. Power MO for high speed applications
An inverter circuit using an SFET is generally used. FIG. 6 is a basic configuration diagram when a power MOSFET is used. Even if a power MOSFET is used, its basic operation is substantially the same as that of the above-described inverter circuit for a power transistor, and therefore a description thereof is omitted.

In the case where the above-described inverter circuit is integrated into a hybrid integrated circuit, the conventional example has dealt with using two insulating metal substrates. That is, a power circuit having a power transistor or a power MOSFET is formed on one substrate, and a small signal circuit such as a drive circuit and a protection circuit is formed on the other substrate, and each circuit is mounted on two substrates. (See FIG. 7).

[0007]

When a power circuit and a small signal circuit are formed on the same substrate surface, there are the following problems. FIG. 8 is a pattern diagram showing one driving circuit for driving a power element (MOSFET) of the small signal circuit. Such a conventional drive circuit is generally configured by connecting a plurality of discrete components or semiconductor chips. In the inverter circuit, it goes without saying that six patterns shown in FIG. 8 are arranged.

[0008] The structure under the pattern wiring forming the drive circuit is formed of a metal substrate, an insulating layer, and a conductor, so that a parasitic capacitance is generated. This parasitic capacitance increases as the pattern wiring in the drive circuit portion becomes longer. For example, when the power MOSFET in the lower arm of the inverter circuit is driven, the power MOSFET in the other upper arm of the pair malfunctions due to the parasitic capacitance. As a result, there is a problem that a short-circuit current flows and the power MOSFET is broken.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a voltage-driven element as a bare chip, and a drive circuit for supplying the output signal to the voltage-driven element. The problem is solved by being integrated on a semiconductor chip, mounted on the metal substrate adjacent to the voltage-driven element, and connecting the electrode to which the voltage of the voltage-driven element is applied via a thin metal wire. is there.

By integrating a drive circuit composed of a plurality of circuit elements for switching voltage-driven elements on one semiconductor chip, it is possible to significantly reduce the number of pattern routing lines in the drive circuit. As a result, the parasitic capacitance under the pattern wiring can be significantly reduced. Further, by integrating the drive circuit on the semiconductor chip, the area of the drive circuit portion is significantly reduced as compared with the conventional case, and the size of the hybrid integrated circuit can be reduced.

Further, according to the present invention, by employing a metal substrate, the semiconductor chip and the voltage-driven element can be arranged adjacent to each other. For example, the thermal conductivity of Al is superior by one digit or more as compared with a substrate made of ceramic or the like. Therefore, heat generated in the voltage-driven element can be released to the outside, the heat rise of the semiconductor chip on which the drive circuit is integrated can be suppressed, and malfunction of the drive circuit can be prevented. As a result, due to the adjacent arrangement, the drive I
The stray capacitance up to C can be further reduced.

In addition, since the voltage-driven element is a bare chip as shown in FIG. 1, flexible wire bonding can be employed. Therefore, the wiring extending from the vicinity of the semiconductor chip on which the drive circuit is mounted is In a state having flexibility (for example, a wiring having as small a stray capacitance as possible), the wiring can be electrically connected to an electrode to which the voltage of the voltage-driven element is applied by a thin metal wire.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hybrid integrated circuit according to an embodiment of the present invention will be described with reference to the drawings shown in FIGS. FIG. 1 is a plan view of a hybrid integrated circuit according to the present invention, and FIG. 2 is a cross-sectional view taken along line II of FIG. FIG.
As shown in FIG. 2 and FIG. 2, the hybrid integrated circuit 1 of the present invention includes a metal substrate 2, a conductive path 3 formed on the substrate 2 via an insulating layer 6, and a voltage drive mounted on a predetermined position of the conductive path 3. It comprises a mold element 4 and a drive circuit 5 for switching the element 4.

As the metal substrate 2, a metal such as iron, copper, or aluminum can be used. In this embodiment, an aluminum substrate is used. An aluminum oxide film is formed on the surface of the aluminum substrate used in the present embodiment by an anodic oxidation technique, and insulation treatment is performed. A conductive path 3 having a desired shape is formed on one main surface of the substrate 2 via an insulating layer 6.

The insulating layer 6 is made of a resin thin layer such as epoxy or polyimide resin or a plate material such as ceramic. In this embodiment, a thin epoxy resin layer is used, and a copper foil is adhered to the thin layer. The conductive path 3 having a desired shape is formed by etching the copper foil into a predetermined pattern. Needless to say, the conductive path 3 can be formed by printing.

The conductive path 3 is used for the power part 3
a and 3b used for the small signal portion are formed on the same substrate 2. More specifically, the conductive path 3a of the power system is formed in a region defined substantially in the middle of the substrate 2,
A plurality of fixing pads for power are formed on one side of the substrate 2. The conductive path 3b of the small signal system is connected to the conductive path 3 of the power system.
a, a plurality of fixing pads for small signals are formed at the extending end portion.

That is, the fixing pads for the power and the small signal are formed on the peripheral edges of the opposing sides of the substrate 2, respectively, and the small signal circuit and the power circuit are connected as described above. The substrate 2 is partitioned by a substantially intermediate region. A plurality of voltage-driven elements 4 are fixed at predetermined positions on the power path 3a of the power system by soldering. As the voltage-driven element 4, for example, a power MOSFET, an IG
Although elements such as BT and BiMOS can be used, in this embodiment, a power MOSFET is used (hereinafter, the voltage-driven element 4 is referred to as a power MOSFET). Each power MOSFET 4 is arranged so as to form a bridge connection.

A drive circuit 5 for switching each power MOSFET 4 is provided at a predetermined position on the small signal system conductive path 3b.
Chip components such as a capacitor and a chip resistor are fixed. The feature of the present invention is that the power MOSFE
There is a drive circuit 5 for switching T4. That is, a drive circuit having a conventional structure is formed by connecting a plurality of circuit elements such as a transistor, a chip resistor, and a chip capacitor through a desired conductive path. However, in the drive circuit 5 of the present invention, a circuit constituting a conventional drive circuit is integrated on a semiconductor chip.

FIG. 3 is a block diagram showing a driving circuit 5 formed on a semiconductor chip. As shown in FIG. 3, a pre-stage circuit that drives an output circuit based on a predetermined input signal, an output circuit that switches a power MOSFET 4, a constant current circuit that supplies a predetermined stable current to the pre-stage circuit and the output circuit, And a voltage detection circuit for detecting an abnormal voltage when the saturation voltage of the MOSFET 4 rises due to an overcurrent.

The drive circuit 5 is arranged adjacent to each bridge-connected power MOSFET 4 and has a respective conductive path 3.
A hybrid integrated circuit for an inverter having a predetermined output connected by bonding to the inverter can be realized. By the way, by integrating the driving circuit on a semiconductor chip (here, a driving IC), the stray capacitance caused by the metal substrate, the insulating layer, and the wiring can be significantly reduced.
However, when the drive IC and the power MOSFET are mounted on a metal substrate, if the distance is significantly long, an electrical connection via a long wiring is required between them. As a result, a stray capacitance is generated between the drive IC and the power MOSFET, resulting in a malfunction. Therefore, they need to be as close as possible. However, power MOS
When a large current flows through the FET, the temperature rises to near 150 degrees, and if the drive IC reaches a temperature close to this, malfunction will occur again here. However, by using a metal substrate, the temperature rise of the drive IC can be suppressed. That is, the thermal conductivity of Al is superior to other hybrid integrated circuit boards by one digit or more. Therefore, the power MOS
The heat generated from the FET is released to the outside, and the driving I
The temperature rise of the drive IC caused by the self-heating of C
Since it is possible to keep the power MOSFET low enough to release the heat, the drive IC and the power MOSFET can be arranged adjacent to each other. As a result, the driving I
The stray capacitance generated between C and the power MOSFET can also be suppressed, and malfunction can be further prevented.

Furthermore, since the voltage-driven element is a bare chip as shown in FIG. 1, flexible wire bonding can be employed, so that the wiring extending from the vicinity of the semiconductor chip on which the drive circuit is mounted is provided. Can be electrically connected to the electrode to which the voltage of the voltage-driven element is applied by a thin metal wire in a state having flexibility (for example, wiring having as little floating capacitance as possible). it can.

Although the above embodiment has been described using an inverter circuit, the present invention is not limited to an inverter circuit, but includes a hybrid using a voltage-driven switching element such as a power MOSFET such as an active filter circuit. Needless to say, it can be applied to an IC. According to the present invention, each power MOSFET 4
Is integrated on a semiconductor chip, the conventional drive circuit requires a plurality of wiring patterns, but this can be eliminated. As a result, in the related art, the parasitic capacitance is generated in the pattern portion of the leading line, but in the present invention, the parasitic capacitance can be significantly reduced because the drive circuit 5 itself is formed into a chip.

Further, since the drive circuit 5 is integrated on a chip, the area of the drive circuit 5 is significantly smaller than that of the conventional structure, so that the size of the hybrid integrated circuit can be reduced. Furthermore, since the small signal fixing pad and the power fixing pad are provided on the opposite sides of the substrate 2, the effective surface on the substrate 2 can be used to the maximum.

[0024]

As described above, according to the present invention, a drive circuit for driving each power MOSFET is integrated on a semiconductor chip, so that a conventional drive circuit requires a plurality of wiring patterns. On the other hand, in the present invention, it can be unnecessary.

As a result, the parasitic capacitance is generated in the pattern portion of the lead line in the related art. However, in the present invention, since the drive circuit itself is formed into a chip, the parasitic capacitance can be significantly reduced. In addition, the power MOSFET and the drive IC can be arranged adjacently without considering thermal factors, and the adoption of a bare-chip power MOSFET increases flexibility in wiring between the power MOS and the drive circuit. The stray capacitance generated between the driving IC and the driving IC can be suppressed. Therefore, power MOS
Potential change due to capacitance change due to noise at the time of FET switching can be minimized.
An abnormal operation of the FET can be prevented.

In the present invention, since the drive circuit is integrated on the semiconductor chip, the area of the drive circuit itself is remarkably reduced, which has an advantage that it can greatly contribute to the miniaturization of the hybrid integrated circuit. Furthermore, according to the present invention, since the fixed pad for small signals and the fixed pad for power are provided on opposite sides of the substrate, the effective mounting area on the substrate can be enlarged. As a result, the maximum high-density mounting is possible even with a small substrate.

[Brief description of the drawings]

FIG. 1 is a plan view showing a hybrid integrated circuit according to an embodiment of the present invention.

FIG. 2 is a sectional view corresponding to the line II of FIG. 1;

FIG. 3 is a block diagram illustrating a driving circuit.

FIG. 4 is a basic configuration diagram showing an inverter device.

FIG. 5 is a diagram showing a drive circuit of the inverter device.

FIG. 6 is a basic configuration diagram showing an inverter device using a MOSFET.

FIG. 7 is a cross-sectional view showing a conventional hybrid integrated circuit.

FIG. 8 is a plan view illustrating a conventional driving circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02M 7/42-7/98 H01L 25/04

Claims (1)

(57) [Claims] A metal substrate, a conductive path having a desired shape formed on the metal substrate via an insulating layer, a plurality of circuit elements connected at predetermined positions on the conductive path, and a predetermined output signal. A voltage-driven element that performs switching based on the voltage-driven element, wherein the voltage-driven element is a bare chip, and a drive circuit that supplies the output signal to the voltage-driven element is integrated on one semiconductor chip. And an electrode mounted on the metal substrate adjacent to the voltage-driven element and connected to a voltage of the voltage-driven element through a thin metal wire.