JPH05243225A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase resistance to electromigration of an aluminum interconnection. CONSTITUTION:An aluminum film 3 and a platinum film 4 are deposited in this order and are patterned. By heat treatment, these two films are alloyed to form an alloy interconnection 6. Due to the high density alloy film formed of platinum and aluminum, resistance to electromigration and resistance to stress migration of an insulating film are increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to metal wiring and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, it has been well known that aluminum wiring, which has been used for a long time in semiconductor devices, has a low electromigration resistance as a serious drawback (problem), and various improvements have been made. .

The first example is to add an alloying element to aluminum in order to suppress grain boundary diffusion, which is a cause of electromigration, and Cu, Ti, Si, Pd, etc. are added as impurity metals to be added. It has been known.

The second example is a method of covering the surface of an aluminum wiring with an insulating film, and a silicon oxide film doped with phosphorus, a silicon oxide film, a silicon nitride film or the like is used as the insulating film.

As a third example, there is known a method of reducing electromigration by increasing the crystal grain size of aluminum to reduce the crystal grain boundaries.

[0006]

Although this conventional semiconductor device is effective against electromigration of aluminum-based wiring, it has the following problems.

First, in the first example, an aluminum film containing impurities is deposited by a sputtering method in order to deposit on the grain boundaries of aluminum wiring containing impurity metals to suppress diffusion, and therefore etching is performed. There is a problem that the impurity metal remains as a residue during processing.

Further, in the second example, the problem that stress migration occurs due to the insulating film covering the aluminum wiring occurs.

Further, in the third example, it is easy to increase the crystal grain size of the aluminum wiring, but it is difficult to miniaturize because the crystal grain boundaries are etched quickly during the etching process.

[0010]

The semiconductor device of the present invention comprises:
The semiconductor device is provided on a semiconductor substrate with an aluminum film as a main component and a wiring containing an alloy of aluminum and platinum as at least a part thereof.

A method of manufacturing a semiconductor device according to the present invention comprises a step of sequentially laminating and forming an aluminum film and a platinum film on a semiconductor substrate, a step of selectively sequentially etching the platinum film and the aluminum film, and a heat treatment. And a step of alloying the aluminum film and the platinum film to form a wiring.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

1 (a) to 1 (c) are cross-sectional views of a semiconductor chip showing the order of steps for explaining a manufacturing method according to an embodiment of the present invention.

First, as shown in FIG. 1A, an aluminum film 3 having a thickness of 1 μm and a thickness of 0.1 to 0.2 μm are formed on an insulating film 2 provided on a semiconductor substrate 1 by a sputtering method.
Of the platinum film 4 are sequentially deposited and formed. At this time, it is better to keep the temperature of the substrate low. Next, a photoresist film 5 is applied on the platinum film 4 and patterned to form a wiring forming mask.

Next, as shown in FIG. 1B, the platinum film 4 and the aluminum film 3 are anisotropically etched successively using the photoresist film 5 as a mask to form a two-layer structure of the aluminum film 3 and the platinum film 4. Form. Here, since the aluminum film 3 and the platinum film 4 are etched in a laminated structure, there is an advantage that no residue is generated.

Next, as shown in FIG. 1C, after removing the photoresist film 5, heat treatment is performed in a nitrogen atmosphere at 150 ° C. to 450 ° C. to form an alloy wiring 6 of aluminum and platinum.

[0017]

As described above, the present invention has an effect that an alloy wiring excellent in electromigration resistance can be obtained by forming an alloy film of aluminum and platinum having a high density.

Further, since the alloy film having a high density increases the hardness, the resistance to stress migration with respect to the insulating film is also improved, and it is possible to prevent residues from being generated during the etching process.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor chip showing the order of steps for explaining a manufacturing method according to an embodiment of the present invention.

[Explanation of symbols]

 1 Semiconductor substrate 2 Insulating film 3 Aluminum film 4 Platinum film 5 Photoresist film 6 Alloy wiring

Claims (2)

[Claims] 1. A semiconductor device comprising a wiring which is provided on a semiconductor substrate and which mainly comprises an aluminum film and at least a part of which contains an alloy of aluminum and platinum. 2. A step of sequentially laminating and forming an aluminum film and a platinum film on a semiconductor substrate, a step of selectively sequentially etching the platinum film and the aluminum film, and a heat treatment to form the aluminum film and the platinum film. And a step of forming an interconnection to form a wiring.