JPS6024052A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a desired emitter region through a simple process by a method wherein reverse conduction type second and third regions are formed in one conduction type first region, one conduction type fourth region is formed in the second region, a transistor is constituted by the first, second and fourth regions and a diode by the first and third regions, the third and fourth regions are connected by a metallic film and a common electrode is shaped to the metallic film. CONSTITUTION:P type regions 22 and 23 are diffused and formed to an N type Si substrate 21 and an N type region 24 is shaped in the region 22, thus constituting an N-P-N type transistor using the substrate 21 as a collector, the region 22 as a base and the region 24 as an emitter. A diode using the substrate 21 as a cathode and the region 23 as an anode is constituted simultaneously. The whole surface is coated with an oxide film 25 and predetermined openings are bored, the regions 23 and 24 are connected by an Al metallic film 26, and an Al wiring 27 is bonded with the metallic film 26 and an Al wiring 28 is also bonded with the region 22. Accordingly, the emitter region 24 of a desired shape is obtained while current concentration to the region 24 is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor device used for example in motor control.

Technical Background of the Invention and Problems Therein Generally, when a power semiconductor device, such as a power transistor, is used for motor control, the circuit is configured as shown in FIG. That is, motor driving transistors Ql and Q2 are connected in series between a power supply and a ground point, and diodes DI are connected between the collectors and emitters of these transistors Ql and Q2, respectively.

D2 is connected. And the above transistor Q1゜Q
2 are controlled to be conductive by control signals 81 and 82, respectively, and the motor M is driven and controlled by the potential at the connection point of the transistors Ql and Q2. Such a circuit configuration is usually formed by connecting two semiconductor devices in series, each pairing a transistor Q and a diode D as shown in FIG. Conventionally, this semiconductor device has been configured in a hybrid manner as shown in FIG.

First, after forming the power transistor Q chip and the diode D chip in separate processes, a metal plate 10 is installed to connect the collector region QC of the transistor Q and the cathode Dk of the diode D, and also connect the emitter Q
e and the anode Da are wired by bonding with a metal wire such as aluminum.

Here, Qb is the base region of transistor Q.

However, with the above configuration, the number of parts during assembly is large, making the assembly process cumbersome, the product yield cannot be improved, and the number of defects occurring during the assembly process is approximately several dozen. Therefore, it is difficult to reduce costs. Furthermore, since a metal line must be bonded onto the emitter Qe of the transistor Q, the shape of the emitter Qe is restricted. This is because a metal wire with a diameter of about KO15jIIl is generally used as a bonding wire in power transistors used for motor control, etc., and an area of at least 1 x 2 x 2 is required as a bonding pad. The emitter Qe must also have an area of 1u×2 or more.

Furthermore, current concentration occurs directly under the wire in the emitter region, resulting in problems such as failure to obtain desired characteristics and destruction of the transistor Q.

[Object of the Invention] The present invention has been made in consideration of the above-mentioned circumstances, and can be manufactured through a relatively simple process, and can obtain an emitter region of a desired shape, and furthermore, can form a part of the emitter. An object of the present invention is to provide a semiconductor device in which current concentration does not occur.

[Summary of the Invention] Second and third regions of opposite conductivity type are formed in a first region of one conductivity type, a fourth region of one conductivity type is formed in the second region, and a fourth region of one conductivity type is formed in the second region. 1. The second and fourth regions constitute a transistor, and the first and third regions constitute a diode. connecting the third area and the fourth area;
The common electrode in the area is taken out from above the third area.

[Embodiments of the invention] An embodiment of the present invention will be described using FIG. 4.

KP type regions n and 23 are formed in an N type semiconductor substrate 21, and an N type region array is further formed in the P type region ρ. Semiconductor substrate 21. The P-type region η and the N-type region array serve as the collector, base, and emitter of the NPN transistor, respectively, and the semiconductor substrate 21 and the P-type region n serve as the cathode and anode of the diode, respectively. Connect the P-type area and the N-type area column with a metal IX such as aluminum, bond an aluminum metal wire nail onto the P-type area, and take out the common electrode of the P-type area and the N-type area column. . Further, an aluminum metal line is bonded to the surface of the P-type region n. Note that 5 is an oxide film.

This monolithic structure allows the transistor and the diode to be formed at the same time, and the number of bonding operations is reduced, which facilitates manufacturing. Further, since the electrode is taken out from above the P-type region, current concentration does not occur in a part of the emitter, and a substantially uniform current flows throughout the emitter.

Furthermore, since the N-type region array is connected to the P-type region through a metal film rather than bonding, a bonding pad is not required, and the N-type region array can take any shape.

For example, if you want to use this transistor in a high frequency region, you can make it have a unique shape that increases the perimeter of the emitter, that is, the N-type region array, or divide the emitter and use multiple N-type region arrays as the P-type region. It can also be formed in n.

In order to prevent current concentration from occurring in a part of the emitter, the bonding position of the aluminum metal line n must be placed above the metal film above the part sandwiched between the P-type region n and the bottom of the semiconductor substrate 21. Another possible method is to do so. However, since the film thickness of the metal [26] is thinner than other parts at this position, migration of the metal film or corrosion due to moisture is likely to occur. Since the metal film % becomes wiring resistance, the forward voltage of the diode becomes high, which is not practical. - [Effects of the Invention] According to the present invention, it is possible to obtain a semiconductor device having a carved ivy region of a desired shape and in which current concentration does not occur in a part of the carved ivy region, through a relatively simple process. can.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a motor control circuit, Fig. 2 is a circuit diagram of a power semiconductor device, Fig. 3 is a sectional view showing a conventional power semiconductor device, and Fig. 4 is a circuit diagram showing an embodiment of the present invention. FIG. 21...Semiconductor substrate, n, 23...P-type head region, U...N-type region, base...metal film, n, 28...metal line. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) - A first region of conductivity type, second and third regions of opposite conductivity type formed in this first region, and this second region.
a fourth region of one conductivity type formed in the region; and means for connecting the third and fourth regions;
．． In the semiconductor device in which the second and fourth regions constitute a transistor and the first and third regions constitute a diode, a common electrode of the third and fourth regions is arranged on the third region. A semiconductor device characterized in that it is taken out from. (2) The semiconductor device according to claim 1, wherein the connecting means is a metal film.