JPH02275638A - Semiconductor device - Google Patents

Abstract

PURPOSE:To relax the concentration of large currents at the corner sections of an emitter region by forming the emitter region of a bipolar transistor in a plane shape that the corners of a rectangle are rounded. CONSTITUTION:A collector region 2, a base region 3 and an emitter region 4 are shaped to a silicon substrate 1, an oxide film is applied, a collector- electrode leading out window 5, a base-electrode leading-out window 6 and an emitter-electrode leading-out window are bored, and a collector wiring 8, a base wiring 9 and an emitter wiring 10 are formed through the evaporation of Al and selective etching. The emitter region 4 and an emitter-electrode leading-out window 7 are formed in an octagonal shape that corners are rounded. Consequently, corners are rounded when a photo-resist is patterned and etched on actual manufacture, and gentle curves are shaped substantially. Accordingly, an electric field is not concentrated, thus preventing electrostatic breakdown.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device using a bipolar transistor as an electrostatic protection element.

[Conventional technology]

A conventional semiconductor device will be explained with reference to the drawings.

FIG. 2 is a plan view of an example of a conventional bipolar transistor.

When an NPN bipolar transistor is used as an electrostatic protection element, when designing a mask, the emitter region 4 is designed to have a large area in consideration of the large current that is instantaneously passed. The only difference was the area of the emitter region 4, and the planar shape and other aspects were manufactured in the same manner as other transistors constituting the semiconductor device.

[Problem to be solved by the invention]

When the conventional semiconductor devices described above are subjected to a destructive test using the DC method, C charge method, etc., some devices do not satisfy the MIL standard (for example, 2000 V or more). In recent years, there has been a particular demand for higher performance, and for this reason, it has become possible to achieve higher performance by making the collector base junction and emitter base junction of bipolar transistors shallower. are increasing. As shown in FIG. 2, the electrostatic breakdown portion 11 tends to occur at the corners of the rectangular emitter region 4 where the electric field is concentrated. That is, electric field concentration occurs at the corners of the rectangular emitter region 4, and the base-emitter junction and collector-base junction are destroyed by so-called aluminum spikes in which aluminum sinks into the silicon substrate 1 due to Joule heat or the like.

As described above, conventional bipolar transistors have the disadvantage that they are destroyed by the electrostatic field before they have a protective effect.

[Means to solve the problem]

The present invention is a semiconductor device using a bipolar transistor as an electrostatic protection element, characterized in that the planar shape of the emitter region of the bipolar transistor is an obtuse polygon.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of one embodiment of the present invention.

After forming a collector region 2, a base region 3, and an emitter region 4 on a silicon substrate 1 using the same technique as before and depositing an oxide film, a collector electrode extraction window 5, a base electrode extraction window 6, and an emitter electrode extraction window are opened. . Collector wiring 8, base wiring 9, and emitter wiring 10 are provided by vapor deposition of A1 and selective etching.

In this embodiment, the emitter region 4 and the emitter electrode extraction window 7 have rounded hexagonal corners.

To give a numerical example, the dimensions of the emitter region 4 are 10 μm×
When the thickness is 20 μm, the shape is a right-angled isosceles triangle with a negative side of 3 μm and a rounded corner.

With this shape, during actual manufacturing, there will be no corners during photoresist patterning or etching, and the shape will essentially become a gentle curve. Since there are no corners, no electric field concentration occurs, and therefore electrostatic damage is prevented.

〔Effect of the invention〕

As explained above, in the present invention, since the emitter region has a rectangular planar shape with rounded corners, it is possible to alleviate large current concentration at the corners of the emitter region, and it is possible to reduce the concentration of large currents at the corners of the emitter region. This has the effect of preventing short circuits.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a plan view of an example of a conventional bipolar transistor. 1... Silicon substrate, 2... Collector region, 3...
・Base region, 4... Emitter region, 5... Collector electrode extraction window, 6... Base electrode extraction window, 7...
・Emitter electrode extraction window, 8...Collector wiring, 9・
...Base wiring, 10...Emitter wiring, 11...
Electrostatic damage part. )1 cause

Claims (1)

[Claims] 1. A semiconductor device using a bipolar transistor as an electrostatic protection element, wherein an emitter region of the bipolar transistor has an obtuse polygonal planar shape.