JP2894402B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MOS gate type semiconductor device represented by an insulated gate type bipolar transistor (IGBT), a field effect type transistor (MOSFET) or the like, or a power switching element such as a bipolar transistor. The present invention relates to a semiconductor device, particularly to an internal wiring structure thereof.

[0002]

2. Description of the Related Art Recently, MOS gate type semiconductor devices mentioned above have been frequently used as power switching elements employed in general-purpose inverters and the like. By the way, since the power switching element is an element that controls the conduction of a high voltage and a large current at a high switching frequency, it is desired that the switching time and the switching loss are small. For this reason, for example, in a conventional insulated gate bipolar transistor, the lead wire of the gate terminal is separated from the main terminal and internally wired to reduce the inductance component of the lead wire, and the influence of the main current is applied to the gate signal as much as possible. No countermeasures are taken.

[0003]

By the way, when the speed of the switching element is increased, the following adverse effects are caused. That is, in a switching element having a fast turn-on / turn-off response speed, a current change di / dt at the time of turn-on / turn-off increases, and a surge voltage generated based on the change may cause element destruction or malfunction as follows. . That is, in the inverter circuit, two switching elements (IGB
When T) alternately turns on and off, a very high dv / dt voltage is applied between the collector and the emitter of the off-side element at the time of reverse recovery of a flywheel diode (FWD) connected in parallel with the switching element. , This dv / d
A current flowing to charge the junction capacitance between the collector and the gate with the t voltage may cause the voltage between the gate and the emitter to rise above the gate threshold and cause a false ignition, leading to a series short circuit of the switching elements.

As another problem, when a switching element is incorporated in various devices for use, it is necessary to adapt the operating characteristics of the device, particularly the turn-on speed (turn-on time), to the operating conditions of the applied device. From the viewpoint, there is a demand for a switching element whose turn-on speed can be adjusted. The present invention has been made in view of the above points, and has as its object to improve the internal wiring structure to solve the above-described problem, suppress generation of an excessive surge voltage at the time of switching operation, and prevent element destruction and malfunction. It is another object of the present invention to provide a semiconductor device capable of preventing the above and adjusting the speed of the switching operation according to the demand of the application.

[0005]

In order to achieve the above object, in the semiconductor device of the present invention, a part of the lead wire of the auxiliary terminal is internally wired along the conductor of the main terminal, and the current of the main terminal is reduced. Mutually induced coupling is assumed to reduce the rate of change of the control signal by the mutually induced electromotive force induced in the lead wire by the change.

Further, as an embodiment of the above-mentioned structure, there is a structure in which a lead wire of an auxiliary terminal is wound in a coil shape so as to follow the main terminal conductor. And the setting of the switching time,
The adjustment is performed by adjusting the mutual inductive coupling between the main terminal conductor and the auxiliary terminal lead wire.

[0007]

According to the above arrangement, when the current flowing through the main terminal changes with the start of the switching operation of the semiconductor device, a mutual induced electromotive force is induced on the lead wire of the auxiliary terminal along the main terminal conductor due to the change in current. This electromotive force lowers the rising and falling rates of the control signal, and makes the rising and falling of the signal waveform gentle. As a result, the rate of change di / dt of the main terminal current is reduced, and the occurrence of an excessive surge voltage due to this is suppressed.

In this case, by adjusting the length of the auxiliary terminal lead wire along the main terminal conductor and the number of turns of the coil, the degree of mutual inductive coupling (mutual inductance) between the two is changed, whereby the switching operation is performed. , The switching time changes. Therefore, by using this function, the turn-on characteristics of the semiconductor device can be adjusted according to the requirements of the application.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes an insulating substrate having conductor patterns 1a to 1c formed on the upper surface, 2 denotes a semiconductor element (IGBT) mounted on the conductor pattern 1a of the substrate 1 with the electrode surface of the collector facing, and 3 denotes a semiconductor. Bonding wires wired between the collector and gate electrodes of the element 2 and the conductor patterns 1b and 1c, and 4 and 5 are conductor packages 1a and 1c.
Collector terminal, emitter terminal (main terminal), 6 is a gate terminal (auxiliary terminal for control signal), 7 is an emitter auxiliary terminal, 8 is a gate terminal 6 and a conductor pattern 1b. The lead wires (flexible wires) wired between the terminal fitting 9 and the lead wires (flexible wires) 10 are wired between the emitter auxiliary terminal 7 and the terminal fitting 11 of the conductor pattern 1c. The components are incorporated in a package (not shown), and the terminals 4 to 7 are drawn out of the package.

Further, the lead wires 8 and 10 are wired so that the middle portions of the wires are inductively coupled along the conductors of the collector terminal 4 and the emitter terminal 5, respectively. In the embodiment of FIG. 1, the lead wires 8, 10 are wired in a direction parallel to the current flowing through the terminal conductors of the collector terminal 4 and the emitter terminal 5, and in the embodiment of FIG. 2, the lead wires 8, 10 are coiled. Wound, and the lead wire 8 is a left-hand thread system,
The lead wire 10 is defined as a right-hand thread system.

With this configuration, when the current flowing through the main terminals (collector terminal 4 and emitter terminal 5) changes during the switching operation of the semiconductor element, the lead wires 8 and 10 of the auxiliary terminals (gate terminal 6 and emitter auxiliary terminal 7) are connected. Induces a mutual induction electromotive force, and this electromotive force acts to reduce the steep rising and falling gradients of the control signal input to the auxiliary terminal.

Next, the turn-on characteristics of the semiconductor device having the above configuration will be described in detail with reference to FIG. Note that FIG.
3A is an equivalent circuit diagram of the semiconductor device, FIG.
It shows the current waveform diagram, where C is the collector terminal,
E is an emitter terminal, e is the emitter auxiliary terminal, G represents a gate terminal, and v _s is the gate terminal G as a control signal
Induced electromotive force mutually collector current, v _m stepped drive voltage, i is the externally applied between the emitter auxiliary terminal e and _{(v m = M · di /} dt, M: mutual inductance), v _g is This is the voltage applied to the gate electrode of the device.

That is, a step-like drive voltage v that rises sharply between the G terminal and the e terminal at turn-on.
the collector current i starts to flow by applying _s, acts in the opposite direction to the voltage v _s are mutually induced electromotive force v _m is induced. Thus, the voltage v _g applied to the gate electrode of the element becomes gentle rises gradient as represented by a solid line, increase rate di / dt of the collector current i is suppressed as indicated by a solid line low in proportion thereto. At the time of turn-off, a sharp fall of the collector current is mitigated by the reverse operation. Thus, generation of an excessive surge voltage in the element described above can be suppressed, and element destruction and malfunction can be prevented. Incidentally, (b) a collector current i expressed by a dotted line in the figure, the waveform of the gate voltage v _g is shows the waveforms in the semiconductor device of the conventional structure, the rising gradient that is steeper than the solid line.

1 and 2, the length of the leads 8, 10 along the terminal conductors of the collector terminal 4 and the emitter terminal 5 and the number of turns of the coil are changed to change the length between the main terminals. Changes the degree of mutual inductive coupling, thereby changing the switching characteristics. Therefore, when the lead wire of the auxiliary terminal is internally wired in the process of assembling the semiconductor device,
By adjusting the degree of mutual induction coupling between the main terminal and the auxiliary terminal lead wire, the turn-on speed of the semiconductor device can be set according to the requirements of the application.

[0015]

As described above, according to the structure of the present invention, on the internal wiring structure of the semiconductor device, a part of the lead wire of the auxiliary terminal is arranged along the conductor of the main terminal to mutually guide the two. By providing a simple means for coupling, it is possible to suppress an excessive surge voltage generated at the time of a switching operation of the semiconductor element to prevent element destruction and malfunction, and to adjust the degree of mutual inductive coupling to achieve a purpose. The switching time of the semiconductor device, that is, the turn-on speed of the semiconductor device can be easily adjusted in accordance with the above-mentioned requirements.

[Brief description of the drawings]

FIG. 1 is an assembly configuration diagram of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is an assembly configuration diagram of an embodiment different from FIG.

3A and 3B are explanatory diagrams of switching operation characteristics according to the embodiment of FIGS. 1 and 2; FIG. 3A is an equivalent circuit diagram of a semiconductor device;
(B) is a diagram showing voltage and current waveforms at the time of turn-on operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Semiconductor element (insulated gate bipolar transistor) 4 Collector terminal 5 Emitter terminal 6 Gate terminal 7 Emitter auxiliary terminal 8 Lead wire (gate) 10 Lead wire (emitter)

Claims (3)

(57) [Claims] In a semiconductor device having a semiconductor element mounted on a substrate and leading a main terminal and a control auxiliary terminal, a part of a lead wire of the auxiliary terminal is internally wired along a conductor of the main terminal, A semiconductor device characterized in that mutual inductive coupling is performed such that a rate of change of a control signal is reduced by a mutual induced electromotive force induced in a lead wire by a change in a main terminal current. 2. The semiconductor device according to claim 1, wherein a lead wire of the auxiliary terminal is wound in a coil shape and extends along the main terminal conductor. 3. The semiconductor device according to claim 1, wherein the switching time is set by adjusting the mutual inductive coupling between the main terminal conductor and the auxiliary terminal lead. .