Sanyo Electric Co., Ltd.

Sanyo Semiconductor Co., Ltd.

Sanyo Semiconductor Manufacturing Co., Ltd.

Gifu Sanyo Electronics Co., Ltd.

Tetsuya Yoshida

Tetsuya Okada

Hiroaki Saito

Shigeyuki Murai

Kikuo Okada

Takuji Miyata

Mitsuhiro Yoshimura

Mitsuyuki Kobayashi

Provided is a semiconductor device that can reduce the resistance in a horizontal direction of a substrate. A current path in a horizontal direction of a substrate is formed in a direction along a short side of the substrate (chip). For example, adopted is a layout in which an element region on an input terminal side and a current extraction region on an output terminal side are aligned along the short side of the chip. Furthermore, a first bump electrode and a second bump electrode, which are respectively connected to the input terminal and the output terminal, are arranged along the short side of the chip. Thus, the current path in the substrate in the horizontal direction in the substrate is formed to have a wide width and a short length. Accordingly, the resistance of the substrate in the horizontal direction is reduced.

Semiconductor device

Provided is a semiconductor device in which a high concentration n type impurity region to be a conductive path and a drain electrode are disposed in an outer circumferential end of the chip to be an inactive region as a device region. Thereby, an up-drain structure is obtained without reducing the device region or without increasing the size of a semiconductor chip. The provided n type impurity region and drain electrode causes a depletion layer of a substrate to be terminated without needing an additional conventional annular region or shield metal. This is because the n type impurity region and the drain electrode also function as the annular region and the shield metal, respectively. With this configuration, a MOSFET with the up-drain structure having necessary components is obtained, while avoiding a reduction of the device region or an increase of the chip area.

As a discrete semiconductor chip, there has been known one that enables flip-chip mounting by providing first and second electrodes in a current path above a first surface of a semiconductor substrate. However, there is a problem that a horizontal current flow in the substrate increases resistance components. A first electrode and a second electrode, which are connected to an element region, are provided above a first surface. Moreover, a thick metal layer having corrosion resistance and oxidation resistance and also having a low resistance is provided above a second surface. Thus, resistance components of a current flowing in a horizontal direction of a substrate are reduced. Moreover, by appropriately selecting a thickness of the thick metal layer, a resistance value of a device can be reduced while suppressing a cost increase. Furthermore, by adopting Au as the thick metal layer, defects such as discoloration of the thick metal layer with time can be prevented.

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.

In a semiconductor device, a variable-potential insulated electrode and a gate region are kept at the same potential through an aluminum layer. This device is mainly used as a voltage-driving type semiconductor device. By varying the voltage applied to the variable-potential insulated electrode through a gate electrode, a conductive path is formed in a channel region to switch on the device. The channel region turns into an N-type region when a positive potential is applied to the gate electrode, and turns into a pseudo P-type region when a ground potential or negative potential is applied to the gate electrode.

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Gunma, Japan

Tetsuya Yoshida