JPS62144355A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To prevent the alloying of gold and aluminum, and to obtain a device with a wiring layer having high reliability by constituting an electrode of gold or a gold group alloy and the wiring layer of multilayer metallic films containing a tungsten layer and an aluminum layer and interposing the tungsten layer between the electrode and the aluminum layer. CONSTITUTION:Electrodes 2 are organized of gold or a gold group alloy, and a wiring layer is formed of multilayer metallic films including a tungsten layer 6 and an aluminum layer 4 in succession from the electrode 2 side. The electrodes 2 composed of a gold-germanium alloy are shaped onto a semi- insulating gallium arsenide substrate 1 as the structure of a wiring section for a semiconductor integrated circuit such as a compound semiconductor integrated circuit, and a multilayer interconnection layer formed in order of titanium 5/tungsten 6/aluminum 4 from the substrate side is shaped as a wiring layer connected to the electrodes 2. Accordingly, the alloying reaction of gold and aluminum can be prevented, thus acquiring the semiconductor integrated circuit having high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a semiconductor integrated circuit that can be used in ultra-high-speed electronic computers, high-speed signal processing circuits, and the like.

BACKGROUND OF THE INVENTION In recent years, semiconductor integrated circuits have been used as key devices.

Hereinafter, a conventional semiconductor integrated circuit as described above will be explained using a compound semiconductor integrated circuit with reference to the drawings.

FIG. 2 shows a purchase t1h side view of a conventional gallium arsenide integrated circuit. In FIG. 2, 1 is a semi-insulating gallium arsenide substrate on which an integrated circuit is formed. Reference numeral 2 denotes an electrode of an element constituting an integrated circuit such as a field effect transistor or a diode, and is made of gold or gold thread alloy. 3 is an insulating film that electrically insulates the electrode 2 and the upper wire 1jη4. 4 is an aluminum wiring layer that electrically connects the individual electrodes.

Problems to be Solved by the Invention In the integrated circuit configured as described above, the wiring layer 4 made of aluminum and the wiring layer 4 made of gold or gold thread alloy are in direct contact at the opening provided in the insulating film 3. Therefore, an alloy of gold and aluminum is easily formed when left at high temperatures for a long time.As is well known, this alloy of gold and aluminum is extremely brittle and increases the contact resistance between the electrode and the wiring layer. This has the disadvantage that the operation of the device is eventually stopped.

In view of the above-mentioned drawbacks, the present invention provides a conductor integrated circuit which prevents alloying of gold and aluminum and has a high wiring layer (i) of 1.gamma.11.

Means for Solving the Problems In order to solve the above problems, the semiconductor integrated circuit of the present invention has electrodes made of gold or a gold thread alloy, and wiring layers made of a multilayer gold film including a tungsten layer and an aluminum layer. It has a structure in which a tungsten layer is interposed between the electrode and the aluminum layer.

Function: With this configuration, the tungsten layer provided in the middle acts to suppress the diffusion of gold and aluminum, and prevents the formation of an alloy of gold and aluminum, resulting in a highly reliable semiconductor integrated circuit. That will happen.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a structural sectional view of a wiring portion of a compound semiconductor integrated circuit according to an embodiment of the present invention. In Figure 1, 1 is a semi-insulating gallium arsenide substrate with a specific resistance of 10'Ωα or more, 2 is a gold-germanium alloy, 3 is silicon nitride, and the above is the same as in Figure 2. . Reference numeral 4 denotes a multi-layer interconnection layer formed from titanium/tungsten/aluminum from the substrate side.

As above, I'! In the formed gallium arsenide integrated circuit, the gold-germanium alloy forming the electrode and the aluminum of the wiring layer are not in direct contact with each other, but a tungsten layer is interposed between them, and this serves to stop the diffusion of gold and aluminum. 25 in the gallium arsenide integrated circuit of the present invention.
A high temperature storage test at 0°C was conducted, but no abnormality was observed even after more than 200 hours, confirming the high reliability of the wiring layer.

In this embodiment, the wiring layer is made of titanium/tungsten/aluminum, but titanium is used to improve the adhesion between the interlayer insulating film and the wiring layer, and chromium or the like may be used instead of titanium.

Effects of the Invention As described above, the present invention provides a semiconductor integrated circuit using gold or a gold thread alloy as an electrode, in which an electric current fl 1
111, by providing a multilayer metal layer containing a tungsten layer and an aluminum layer, it is possible to prevent the alloy reaction between gold and aluminum, and a highly reliable semiconductor integrated circuit can be obtained.The practical effect is that There is something big.

[Brief explanation of drawings]

FIG. 1 is a structural sectional view of a compound semiconductor integrated circuit according to an embodiment of the present invention, and FIG. 2 is a structural sectional view of a conventional compound semiconductor integrated circuit. 1...Gallium arsenide substrate, 2...Gold-germanium alloy overlay, 4-...Aluminum layer, 5
...Titanium, bitter, 6...tungsten m. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
Substrate 5-Titanium 1 6--Titanium 11 ＼M゛Fig. 2

Claims (1)

[Claims] (1) A semiconductor integrated circuit characterized in that the electrode is made of gold or a gold thread alloy, and the wiring layer is made of a multilayer metal film including a tungsten layer and an aluminum layer in this order from the electrode side.