Sanyo Electric Co., Ltd.

Sanyo Semiconductor Co., Ltd.

Semiconductor Components Industries, LLC

Sanyo Semiconductor Manufacturing Co., Ltd.

Gifu Sanyo Electronics Co., Ltd.

Kikuo Okada

Tsutomu Aono

Akira Suzuki

Kojiro Kameyama

Katsuyuki Seki

Tetsuya Okada

Koujiro Kameyama

Hiroaki Saito

Shigeyuki Murai

Takahiro Oikawa

Tetsuya Yoshida

Keita Odajima

Naofumi Tsuchiya

Problems with a conventional mesa type semiconductor device, which are deterioration in a withstand voltage and occurrence of a leakage current caused by reduced thickness of an insulation film on an inner wall of a mesa groove corresponding to a PN junction, are solved using an inexpensive material, and a mesa type semiconductor device of high withstand voltage and high reliability is offered together with its manufacturing method. A stable protection film made of a thermal oxide film is formed on the inner wall of the mesa groove in the mesa type semiconductor device to cover and protect the PN junction, and an insulation film having negative electric charges is formed to fill a space in the mesa groove covered with the thermal oxide film so that an electron accumulation layer is not easily formed at an interface between an Ntype semiconductor layer and the thermal oxide film. With the structure described above, an influence of the positive electric charges in the thermal oxide film is weakened and an extension of a depletion layer into the Ntype semiconductor layer at the interface with the thermal oxide film is secured.

Mesa type semiconductor device and manufacturing method thereof

This invention is directed to solving problems with a mesa type semiconductor device, which are deterioration in a withstand voltage and occurrence of a leakage current caused by reduced thickness of a second insulation film on an inner wall of a mesa groove corresponding to a PN junction, and offers a mesa type semiconductor device of high withstand voltage and high reliability and its manufacturing method. After the mesa groove is formed by dry-etching, wet-etching with an etching solution including hydrofluoric acid and nitric acid is further applied to a sidewall of the mesa groove to form an overhang made of the first insulation film above an upper portion of the mesa groove. The overhang serves as a barrier to prevent the second insulation film formed in the mesa groove and on the first insulation film around the mesa groove beyond an area of the overhang from flowing toward a bottom of the mesa groove due to an increased fluidity resulting from a subsequent thermal treatment. As a result, the inner wall of the mesa groove corresponding to the PN junction is covered with the second insulation film thick enough to secure a desired withstand voltage and to reduce a leakage current.

In a power MOS transistor, for example, a source electrode is formed so as to be commonly connected to a plurality of source regions formed on the front surface. Thus, a current density varies based on in-plane resistance of the source electrode, thereby providing the necessity of increasing the number of wires connecting the sources and a lead. In the invention, an electrode structure includes a copper plating layerformed on a pad electrodeby an electrolytic plating method, and a nickel plating layerand a gold plating layer formed so as to cover the upper and side surfaces of the copper plating layerby an electroless plating method.

Electrode structure and semiconductor device

A punch-through type IGBT generally has a thick p-type collector layer. Therefore, the FWD need be externally attached to the IGBT when the IGBT is used as a switching element in an inverter circuit for driving a motor load, and thus the number of processes and components increases. In the invention, trenches are formed penetrating through a collector layer and reaching a buffer layer. A collector electrode is formed in the trenches, too. With this structure, a current path is formed between an emitter electrode and the collector electrode without through the collector layer and functions as the FWD.

Semiconductor device and method of manufacturing the same

In a conventional semiconductor device, there was a problem that, in a guard ring region, a shape of a depletion layer is distorted and stable withstand voltage characteristics cannot be obtained. In a semiconductor device of the present invention, a thermal oxide film in an actual operation region and a thermal oxide film in a guard ring region are formed in the same process. Thereafter, the thermal oxide film is once removed and is formed again. Thus, a film thickness of the thermal oxide film on the upper surface of the guard ring region is set to, for example, about 8000 to 10000 &#x212b;. Accordingly, a CVD oxide film including moving ions is formed in a position distant from a surface of an epitaxial layer. Consequently, distortion of a depletion layer, which is influenced by the moving ions, is suppressed and desired withstand voltage characteristics can be maintained.

Semiconductor device

A semiconductor device includes a power supply semiconductor chip that has a plurality of current passing electrodes and a plurality of control electrodes. Conductive plates are disposed on the current electrodes and the control electrodes, and extend to regions for external connections. The conductive plates also includes connecting regions that are suspended between the chip and the external connection regions and suppers vibration propagating to the chip. One conductive plate unit for the current passing electrodes and another conductive plate unit for the control electrodes are separately soldered on the corresponding electrodes. Alternatively, only one unit may be soldered on the semiconductor chip, and portions of the unit may be removed to fabricate the device. Because of the absence of wire-bonding steps, the semiconductor chip does not receive impact of wire-bonding during the manufacturing process.

Semiconductor device and method for manufacturing same

A semiconductor device includes a power supply semiconductor chip that has a plurality of current passing electrodes. Conductive plates are disposed on the current electrodes, and conductive wires used for an external connection of the device are fixed on the conductive plates, but not directly on the current passing electrode. A large plate is first fixed on the semiconductor chip, and then the back surface of the large plate is removed to form the individual conductive plates. Because the conductive wires are soldered onto the conductive plates, the semiconductor chip does not receive impact of wire bonding. Even when the conductive wires are wire bonded to the conductive plates, the plates may serve as shock absorbers during wire bonding procedure to reduce the impact of the wire bonding.

Method of manufacturing wiring structure of a power semiconductor device

A semiconductor device includes a power supply semiconductor chip that has a current passing electrode. A conductive plate is disposed on the current electrode, and a conductive wire that is used for an external connection of the device is fixed on the conductive plate, but not directly on the current passing electrode. The conductive plate may serve as a shock absorber during wire bonding procedure, and may contact more than one current passing electrodes so that the number of wire bonding procedures is reduced in manufacturing the device.

Growing community of inventors

Saitama, Japan

Kikuo Okada