JPH05235183A - Semiconductor device - Google Patents

Abstract

PURPOSE:To connect wirings at a shortest distance needless of passing through any relay points even if the wiring is a long aerial wiring by providing an insulator strut beneath the aerial metallic wiring. CONSTITUTION:A metallic wiring 2 comprising Ti/Al/Ti/Pt/Au about 500nm thick silicon or gallium arsenic is formed on a semiconductor substrate 1. A strut comprising a silicon film 3, 2mum thick, a silicon film 4 0.5mum thick and a silicon oxide film 5, 2mum thick is formed on a substrate 1. Through these procedures, even a long aerial wiring can be connected at the shortest distance needless of passing through any relay points.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a multilayer wiring structure, and more particularly to a semiconductor device used for high frequencies in the microwave band or higher or for high speed switching.

[0002]

2. Description of the Related Art At high frequencies in the microwave band and above, the influence of wiring capacitance and inductance becomes significant, which interferes with signal transmission. Therefore, a method of passing metal wiring through the air is often used. Further, even in a high-speed switching operation shorter than 1 ns, the operating speed may not reach the characteristics originally possessed by the element due to the influence of the wiring capacitance and the like. Even in such a case, the method of passing the metal wiring in the air becomes effective.

As shown in FIG. 5, a conventional multi-layer wiring structure of a semiconductor device in which metal wiring is passed through the air is such that a metal wiring 2 is formed on a semiconductor substrate 1 made of silicon, gallium arsenide or the like, and the substrate 1 and A silicon oxide film 7 is formed on the metal wiring 2 as a protective film, and an aerial metal wiring 6 connected to the metal wiring 2 through a contact hole formed in the silicon oxide film 7 is formed.

[0004]

In the above-described conventional aerial wiring structure, since the support of the aerial metal wiring is only at two places at both ends, the length of the metal wire in the air cannot be long, and if the wiring length is long, the On the way, as shown in FIG. 5, the metal wiring 2 as a relay wiring must be connected many times. For this reason, the inductance and capacitance of the aerial metal wiring have increased, and the merit of the aerial wiring has been diminished.

Further, in the conventional aerial metal wiring structure, when the adsorption nozzle for carrying pellets comes into contact with the nozzle from above, the aerial metal wiring may be deformed to cause a short circuit with the lower layer metal wiring. It is difficult to automate the handling of pellets because the inductance and capacitance increase due to deformation even if they do not occur.

[0006]

The semiconductor device of the present invention comprises:
Between the aerial metal wiring and the silicon oxide film or the silicon nitride film on the substrate or the metal wiring, a silicon oxide film,
It is provided with a pillar made of a silicon nitride film or the like.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention. On a semiconductor substrate 1 made of silicon, gallium, arsenic or the like, Ti / Al having a thickness of about 500 nm
/ Ti / Pt / Au is formed on the metal wiring 2, and pillars made of a silicon oxide film 3 having a thickness of 2 μm, a silicon nitride film 4 having a thickness of 0.5 μm, and a silicon oxide film 5 having a thickness of 2 μm are formed on the substrate. There is. Then, the aerial metal wiring 6 connecting between the metal wirings 2-2 is formed in a shape straddling the pillar. The air metal wiring 6 is made of Pt / Au and has thicknesses of about 40 nm and about 1 μm, respectively, and its width is about 1 to several μm.

FIG. 2 is a sectional view of the second embodiment of the present invention. In this embodiment, there are three wiring layers in total, and the silicon oxide film 7 having a flat upper surface is provided on the lowermost metal wiring 2 to have a film thickness of 1 or 2 μm. Ti / P on it
A metal wiring 2a made of t / Au and having a thickness of about 500 nm is provided, and a silicon nitride film 8 having a thickness of 500 nm is provided on the metal wiring 2a.
Is covered with.

A silicon oxide film 3 having a thickness of about 2 μm is formed on the silicon nitride film 8, and a film having a thickness of about 10 nm is formed thereon.
A pillar composed of a thick protective film 9 is erected.
The protective film 9 is formed of a two-layer film of Ti / Pt. The air metal wiring 6 is connected to the metal wiring 2 a through a contact hole formed in the silicon nitride film 8 and is formed in close contact with the protective film 9. The structure of this aerial metal wiring is similar to that of the previous embodiment.

FIG. 3 is a sectional view showing a third embodiment of the present invention. In this embodiment, a silicon oxide film 7 having a film thickness of 2 μm and a silicon nitride film 8 having a film thickness of about 30 nm are formed on the semiconductor substrate 1 and the metal wiring 2. A pillar made of a silicon oxide film 3 having a film thickness of 2 μm is formed on the silicon nitride film 8. A narrow gap is provided between the pillar and the aerial metal wiring 6.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention. In this embodiment, the silicon nitride film 4 and the silicon oxide film 5 are formed on the silicon oxide film 7 covering the metal wiring 2.
Two columns composed of and are set up.

[0012]

As described above, according to the present invention, the pillars of the insulator are provided under the aerial metal wiring. Therefore, according to the present invention, it is not necessary to pass through the relay point even in the long aerial wiring. , It becomes possible to connect the wires with the shortest distance. Therefore, according to the present invention, the aerial wiring can be formed with low capacitance and low inductance, and the high frequency characteristics of the semiconductor device can be improved. In addition, the freedom of design is increased by eliminating the need for relay points in the aerial wiring. Further, since it is difficult for the aerial wiring to be deformed when handling the pellets, automation can be easily implemented.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Semiconductor Substrate 2, 2a Metal Wiring 3, 5, 7 Silicon Oxide Film 4, 8 Silicon Nitride Film 6 Aerial Metal Wiring 9 Protective Film

Claims (1)

[Claims] 1. A semiconductor device in which a part of a metal wire is passed through the air, wherein a pillar of an insulator is provided under the air metal wire.