JPH08195410A - Pressurized contact type semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] Accurate positioning of semiconductor chips and contact terminals that also function as pressure and heat radiators for semiconductor devices that are modularized by incorporating multiple semiconductor chips into a package container. Thus, the element breakdown during assembly is prevented and the reliability of the element is improved. [Structure] The chip mounting base 8 on the metal substrate 7 and the semiconductor chip 4 are positioned by the overhanging portion 14 of the positioning guide 2, soldered by the solder sheet 6, and then the contact terminal body 1 is positioned by this positioning guide 2. Then, the convex portion 10 of the contact terminal body 1 and the collector electrode 5 are accurately aligned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to power devices such as insulated gate bipolar transistor (IGBT) modules and the like, and has a first main electrode and a control electrode on one main surface of a substrate and a second main electrode on another main surface. The present invention relates to a pressure contact type semiconductor device in which a plurality of semiconductor chips each having a main electrode are incorporated in the same package.

[0002]

2. Description of the Related Art IGBTs are widely used as power switching devices for applications such as motor PWM control inverters. Also, because this IGBT is a voltage-driven type and easy to handle, the demand for the market is increasing toward larger capacities, and along with the increase in the size of semiconductor chips, there is a trend toward larger capacities. In order to increase the number of modules, a module structure in which a plurality of IGBTs are incorporated in the same package is often adopted.

In an insulated gate element (MOS control device) such as an IGBT, an emitter electrode as a main electrode and a gate electrode as a control electrode are formed side by side on one main surface of a semiconductor chip. Therefore IG
When the BT chip is packaged and assembled, the collector on the second main surface side can be directly mounted on the metal base that also serves as a heat radiator, but the emitter electrode and gate electrode on the first main surface side are separately provided. It is necessary to pull out through the external lead-out terminal. So, in the conventional package assembly structure,
An external lead terminal for the emitter and the gate is provided on the upper surface side of the package case together with the above-mentioned metal base, and an aluminum conductor wire having a wire diameter of about 300 μm is wired between the emitter electrode and the external lead terminal and between the gate electrode and the external lead terminal. I try to bond it and pull it out.

[0004]

By the way, in the above-mentioned conventional assembly structure, although sufficient heat can be dissipated from the collector side, heat is hardly dissipated from the emitter side, so that the current capacity is significantly limited. It Also, in a device with a large current capacity, the number of bonding wires connected to the emitter electrode also increases. Especially, in the configuration in which a plurality of IGBTs are incorporated in the same package to form a module, the number of wires reaches several hundreds. The wiring inductance increases, which causes a problem that a large surge occurs during the switching operation of the IGBT.

On the other hand, in order to solve the problems of heat dissipation and wiring inductance by the above-mentioned assembly structure, the IGBT is built in the flat package and formed on the main surface thereof, like the conventional pressure contact type semiconductor device. It is conceivable that the collector electrode and the emitter electrode are respectively brought into surface contact with the upper and lower electrode plates provided on the package side to be drawn out. However, in the IGBT, if the package-side electrode plate is brought into pressure contact with the emitter electrode on the insulating layer covering the gate electrode, this pressure may also be applied to the gate electrode and destroy the gate electrode structure. A flat element is formed by avoiding the gate electrode portion and providing a portion called a collector electrode having both heat dissipation and current passage and pressurizing the portion. Further, when the pressure contact type flat package is adopted as the IGBT module in the composite device in which the IGBT and the flywheel diode attached to the IGBT are incorporated in the same package, the following problems occur. That is, since the IGBT and the flywheel diode, which are required in terms of electrical characteristics, generally have different chip height dimensions (wafer thickness), different semiconductor chips having different height dimensions are arranged side by side. Then, when the chips are assembled in the same flat package, the heights of the upper surfaces of the chips are not uniform, and it becomes extremely difficult to uniformly press and contact each semiconductor chip. To prevent this, a solder sheet is used to fix the semiconductor chip to the electrode plate of the flat package so as to absorb the height difference.

The alignment of the solder sheet and the semiconductor chip and the alignment of the contact terminal body and the collector electrode on the semiconductor chip during assembly have been conventionally performed with the same heat-resistant plastic positioning guide. FIG. 3 shows a sectional view of a main part of a conventional structure. The side of the chip mounting base on the electrode plate of the flat package is provided with a positioning guide slit,
A groove for solder relief on the upper part and two steps of processing are applied. The processing accuracy of the positioning guide slit is extremely important, and performing high-precision processing by processing two steps requires a high level of technology and increases processing cost.

In order to solve the above-mentioned problems, the present invention provides a two-step structure by providing a protrusion on the bottom of the positioning guide with heat-resistant plastic and fixing the positioning guide to a chip mounting base smaller than a semiconductor chip. It is an object of the present invention to provide a pressure contact type semiconductor device having a structure that requires only one step of processing, does not require high-level processing technology, and can perform highly accurate alignment with easy and inexpensive processing.

[0008]

In order to achieve the above object, the present invention provides a first main electrode and a control electrode on a first main surface,
A plurality of semiconductor chips each having a second main electrode on the second main surface are juxtaposed, and a semiconductor device incorporated in a flat package formed by interposing an insulating outer cylinder between a pair of common electrode plates exposed on both surfaces. Contact terminals that also function as pressure, conduction, and heat radiators are respectively interposed between the first main electrode of the semiconductor chip and the common electrode plate on the package side facing the first main electrode, and each semiconductor chip and each contact terminal body are connected. , The positioning guide is provided on the side surface of the chip mounting base smaller than the semiconductor chip, which is provided on the upper part of the metal substrate sandwiched between the second main electrode and the common electrode plate on the package side facing the second main electrode. Is to fix the bottom of the. It is effective to provide an overhanging portion that is lower than the height of the chip mounting base at the bottom of this positioning guide, and fix the positioning guide to the chip mounting base by this overhanging portion. The positioning guide may be made of heat resistant plastic (liquid crystal polymer).

Further, a first main electrode and a control electrode are provided on the first main surface,
A semiconductor chip having a second main electrode on the second main surface is an insulated gate type element, and a flywheel diode is installed in antiparallel with a plurality of insulated gate type elements in the same flat package and That is, the first main electrode of the device and the anode electrode of the flywheel diode and the package-side common electrode plate facing the first main electrode are provided with contact terminal bodies that also function as pressure and heat radiators, respectively. Further, the insulated gate element is a MOS transistor including an insulated gate bipolar transistor (IGBT) or an insulated gate thyristor (MOS control thyristor).

[0010]

As described above, the common electrode on the package side with respect to the current collecting electrode portion provided in a region other than the gate electrode and having heat dissipation provided for each of the plurality of semiconductor chips incorporated in the flat package with respect to the package electrode. Applying an unreasonable pressure to the gate electrode part of the semiconductor chip by making pressure contact through each contact terminal body that has surface contact with the plate (emitter side) and that secures parallelism and the same height. Without,
Also from this first main surface on the emitter side, heat can be efficiently radiated through the common electrode plate exposed to the contact terminal body and the outer surface of the package. As a result, heat dissipation from the second main surface side on the collector side is dramatically improved, and the current capacity of the semiconductor device can be increased. Moreover, since the bonding wire is not used for connecting the main electrodes, the internal inductance is also reduced.

On the other hand, a plurality of IGBT chips and flywheel diodes are solder-bonded to the substrate while being accurately positioned by a positioning guide finally incorporated in the device. Here, multiple steps such as solder relief groove and positioning guide slit are not formed on the chip mounting base on the metal substrate as in the past, and a protrusion is provided at the bottom of the positioning guide to remove the solder relief allowance. By forming the filter portion, it is not necessary to process the groove formation on the side surface of the chip mounting base, and only the positioning guide slit is processed. By doing so, the positioning guide is accurately aligned with the chip mounting base, and at the same time, the manufacturing process of the element is simplified and the cost is reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of an embodiment of the present invention, in which FIG. 1 (a) is a sectional structural view and FIG.
It is a perspective view of a positioning guide of. In FIG. 3A, the semiconductor chip 4 is fixed on the chip mounting table 8 on the metal substrate 7 via the melted and solidified solder sheet 6.
At this time, the chip mounting base 8, the solder sheet 6, and the semiconductor chip 4 are positioned by the positioning guide 2. With this positioning guide 2, the convex portion 10 of the contact terminal body 1
Are accurately aligned on the collector electrode 5 of the semiconductor chip 4. The metal substrate 7 and the contact terminal body 1 are pressed against the collector electrode plate 12 and the emitter electrode plate 13, which are common electrode plates, by external force. In FIG. 2B, a protrusion 14 is provided on the bottom surface of the positioning guide 2, and the protrusion 14 is lower than the height of the chip mounting table 8. This overhang 14
Is fitted into the chip mounting base 8 and the positioning guide 2 is fixed. Further, a notch 3 for gate wire is provided on the upper part of the positioning guide 2. The metal substrate 7 and the collector electrode plate 12 may be integrated into a common electrode plate.

FIG. 2 is a diagram showing a method of manufacturing an element using the positioning guide according to the present invention. The chip mounting base 8 is provided on the metal substrate 7, and the positioning guide 2 is fitted so that the inner end of the overhanging portion 14 of the positioning guide 2 contacts the side surface 9 of the chip mounting base 8. The semiconductor chip 4 and the semiconductor chip 4 are positioned by the positioning guide 2, the chip mounting base 8 and the semiconductor chip 4 are fixed by the solder sheet 6, and then the contact terminal body 1 is inserted into the positioning guide 2 to project the convex portion of the contact terminal body 1. The contact terminal body 1 is positioned so that the collector electrode 10 and the collector electrode 5 correspond to each other in an accurate correspondence. The positioning guide 2 has a notch 3 for pulling out the gate wire. The chip base 8 and the semiconductor chip 4 are fixed by the solder sheet 6 in a soldering furnace such as a reflow furnace.

By providing the positioning guide 2 with the protruding portion 14, making the thickness of the protruding portion 14 thinner than the height of the chip mounting base 8, and fixing the positioning guide 2 to the chip mounting base 8 smaller than the semiconductor chip 4. A space to be the solder escape allowance portion 15 is formed, and the same effect as the solder escape allowance groove 11 of the conventional structure can be obtained. Further, unlike the conventional case, it is not necessary to provide a solder clearance on the side surface of the chip mounting table 12,
Since only one step is required for the side surface processing, the accurate processing can be easily performed, the current collecting electrode and the contact terminal body can be accurately aligned, and the processing cost can be reduced.

The material of the positioning guide 2 is a heat-resistant plastic (liquid crystal polymer) which can withstand 340 ° C. or higher, which is higher than the soldering temperature of 320 ° C.
Further, with the above configuration, the semiconductor chip 4 can be cooled on both sides via the substrate 7 and the contact terminal body 1. The semiconductor chip 4 is a MOS transistor including an IGBT, an insulated gate element such as a MOS control thyristor, and a flywheel diode.

Although FIG. 1 shows the case where there are two semiconductor chips, a larger number of semiconductor chips may be arranged. When both the insulated gate element and the flywheel diode are present, they are arranged so as to be antiparallel to each other.

[0017]

According to the present invention, a plurality of semiconductor chips can be placed in a flat package in a flat package so that a uniform pressure contact can be achieved by surface contact without applying an undue pressing force to the gate electrodes of the semiconductor chips. Assembled, allowing heat to be dissipated from both sides of each semiconductor chip to increase the current capacity, and because the bonding wire is not used to draw out the current from the main electrode, the internal wiring inductance is also reduced, and the flat package has a hermetically sealed structure. In combination with this, the reliability of the semiconductor device can be greatly improved. In addition, the assembly guide ensures accurate positioning between the element and the contact terminal body, and pressure applied to the gate electrode portion due to displacement or the like is eliminated so that the gate electrode portion is not damaged.

Conventionally, it was necessary to process the chip mounting base and the solder relief groove on the metal substrate in a plurality of steps. However, in the present invention, the machining of the solder relief groove is unnecessary, and it is possible to easily and accurately perform machining. The positioning guide and the chip mounting base can be positioned with high accuracy, and therefore the contact terminal body and the collector electrode on the semiconductor chip can be positioned with high accuracy. Further, the processing steps are simplified, and the manufacturing cost can be significantly reduced.

[Brief description of drawings]

1A and 1B are configuration diagrams of a main part showing an embodiment of the present invention, in which FIG. 1A is a sectional structural view and FIG. 1B is a perspective view of a positioning guide.

FIG. 2 is a diagram showing a method of manufacturing an element using a positioning guide according to the present invention.

FIG. 3 is a sectional view showing a conventional main part configuration in FIG.
FIG. 3B is a perspective view of the positioning guide.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact terminal body 2 Positioning guide 3 Gate wire notch 4 Semiconductor chip 5 Current collecting electrode 6 Solder sheet 7 Metal substrate 8 Chip mounting base 9 Side surface of chip mounting base 10 Convex portion of contact terminal body 11 Solder escape substitute groove 12 Collector Electrode plate 13 Emitter electrode plate 14 Overhang 15 Solder relief area

Claims (5)

[Claims] 1. A plurality of semiconductor chips, each having a first main electrode and a control electrode on a first main surface and a second main electrode on a second main surface, are arranged side by side and between a pair of common electrode plates exposed on both surfaces. In a semiconductor device incorporated in a flat package having an insulating outer tube interposed therebetween, a pressure member, a conductor member, and a heat radiator are provided between the first main electrode of each semiconductor chip and the common electrode plate on the package side facing the first main electrode. By interposing the double-ended contact terminal body,
Smaller than the semiconductor chip, provided on the metal substrate sandwiched between the second main electrode and the common electrode plate on the package side facing the second main electrode so that each semiconductor chip and each contact terminal body correspond to each other. A pressure contact type semiconductor device characterized in that a bottom of a positioning guide is fixed to a side surface of a chip mounting base. 2. The pressure contact according to claim 1, wherein an overhanging portion lower than the height of the chip mounting base is provided at the bottom of the positioning guide, and the positioning guide is fixed to the chip mounting base by the overhanging portion. Type semiconductor device. 3. The positioning guide is made of heat resistant plastic (liquid crystal polymer).
The pressure contact type semiconductor device described. 4. A semiconductor chip having a first main electrode and a control electrode on a first main surface and a second main electrode on a second main surface is an insulated gate element, and a plurality of insulating elements are provided in the same flat package. A flywheel diode is installed in antiparallel with the gate type element, and pressure is applied between the first main electrode of the insulated gate type element and the anode electrode of the flywheel diode and the common electrode plate on the package side facing the anode electrode, respectively. 2. The pressure contact type semiconductor device according to claim 1, further comprising a contact terminal body that also functions as a conductor and a heat radiator. 5. The pressure contact type semiconductor device according to claim 4, wherein the insulated gate element is a MOS transistor including an insulated gate bipolar transistor (IGBT) or an insulated gate thyristor (MOS control thyristor). .