JPS6377117A - Manufacture 0f semiconductor device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] This is an improvement in a method for manufacturing a semiconductor device. In particular, metal electrodes
This is an improvement that improves the barrier effect of the interconnect barrier layer.

In a method of manufacturing a semiconductor device in which an aluminum electrode is formed on silicon, a barrier layer is formed, a silicon dioxide or silicon nitride film is formed, and the silicon dioxide or silicon nitride film is anisotropically etched. This remains only on the side wall of the stepped portion of the barrier layer, and metal electrodes and wiring are formed thereon.

[Industrial application field]

This invention relates to improvements in methods for manufacturing semiconductor devices. In particular, the present invention relates to improvements in methods for manufacturing metal electrodes and interconnections that can improve the barrier effect of barrier layers.

[Conventional technology]

Aluminum is often used as the material for metal electrodes in semiconductor devices manufactured using silicon substrates.
Aluminum, which is an M group metal, functions as a p-type impurity when diffused into silicon, and furthermore, when the p-n junction formed in the silicon substrate is shallow, it becomes a spike that destroys the p-n junction. .

Conventionally, therefore, aluminum and silicon have been separated by a barrier layer made of refractory metal nitride, hafnium nitride, zirconium nitride, alloy of titanium and tungsten, etc. In particular, shallow emitters have been formed using ion implantation. When forming using a polycrystalline silicon film, a polycrystalline silicon film is also required as a protective film against implanted ions, and an aluminum film is also required between the polycrystalline silicon film and the barrier layer to ensure good contact with the barrier layer. For reasons such as the need for interposition between the parts, the structure shown in FIG. 5 was adopted, and was manufactured in the following manner.

Referring to FIG. 5, electrode contact openings are formed in an insulating film 2 made of silicon dioxide or the like formed on a silicon substrate 1 to provide protection against implanted ions. Polycrystalline silicon film 4 is used as I film with thickness t, o
After forming a 000000000 film, ion implantation is performed to form an emitter region 5, and a titanium or aluminum film is formed as a contact layer to a thickness of 100 to 500000 μl, and titanium nitride, hafnium nitride, zirconium nitride, titanium and tungsten, etc., with a thickness of 1,200 mm.
An aluminum film is formed as the main material of the electrode, and this is patterned to form the electrode/wiring 9.

[Problem that the invention seeks to solve]

With the metal electrodes and wiring of the prior art described above, the effect of the barrier layer is not sufficient, and aluminum and silicon penetrate through the barrier layer and diffuse into each other, resulting in a considerable amount of aluminum being mixed into the silicon substrate. There are drawbacks.

An object of the present invention is to eliminate this drawback, and to provide a method for manufacturing a semiconductor device having a metal electrode with an excellent barrier effect.

[Means for solving problems]

The means taken by the present invention to achieve the above object is to form a film 7 of a frac metal nitride (titanium nitride, hafnium nitride, zirconium nitride, alloy of titanium and tungsten, etc.) as a barrier layer. After that, a film 10 of silicon dioxide or silicon nitride is formed, and this film 10 of silicon dioxide or silicon nitride is anisotropically etched so that it remains only on the sidewall of the stepped portion of the barrier layer 7 and is etched on top of it. The purpose is to form metal electrodes/wirings 9.

[Effect]

In order to improve the barrier effect of the barrier layer, methods such as applying heat treatment or plasma treatment after forming the material used as the barrier layer or the barrier layer have been adopted. However, we have not obtained sufficiently satisfactory results.

Therefore, the inventor of the present invention conducted repeated experiments to investigate the mode of diffusion of aluminum penetrating the barrier layer, and as a result, as shown by A in FIG. It was confirmed that there is.

The present invention takes advantage of this newly discovered property in a region where significant diffusion occurs (the sidewall of the stepped portion of the barrier layer, indicated by A in FIG. 4).

Safe! In this method, silicon dioxide or silicon nitride [I]iIO is formed as an I film, and metal electrodes and wiring are formed thereon. As a result, the barrier effect of the barrier layer is significantly improved.

〔Example〕

Hereinafter, a method for manufacturing a diode according to an embodiment of the present invention will be further described with reference to the drawings.

Refer to FIG. 2. An insulating film 2 such as silicon dioxide is formed on a silicon substrate 1 of one conductivity type, and an electrode contact opening 3 is formed therein.
Polycrystalline silicon film 4 as a protective film against implanted ions
This polycrystalline silicon film 4 is formed to a thickness of 1,000 yen by ion implantation of impurities of the opposite conductivity type.
-N junction 51 is formed.

Next, a titanium film or aluminum g16 is formed to a thickness of 100 to 500 mm as a contact layer, and a refractory metal nitride, such as titanium nitride, hafnium nitride, zirconium nitride, or an alloy of titanium and tungsten, is formed. A barrier layer 7 is formed to a thickness of 1,200 nm and a silicon dioxide or silicon nitride film 10 is formed to a thickness of 1.0 mm.
Formed to a thickness of 0.00 people.

Referring to FIG. 3, this silicon dioxide or silicon nitride film 10 is anisotropically etched so that it remains only on the sidewalls of the step portion of the barrier layer 7. On top of that is a metal electrode! ! It is to form 9.

Refer to FIG. 1. The above laminated body is patterned to form an electrode φ wiring 9.

In the metal electrode manufactured through the above steps, a silicon dioxide or silicon nitride film 10 is formed as a protective film in the region where diffusion occurs significantly (the sidewall of the stepped portion of the barrier layer indicated by A in FIG. 4). Therefore, its barrier effect is extremely good.

〔Effect of the invention〕

As explained above, in the method for manufacturing a semiconductor device according to the present invention, after forming a barrier layer, a film of silicon dioxide or silicon nitride is formed on the barrier layer, and this film of silicon dioxide or silicon nitride has anisotropic properties. etching, and this is called the trophic area where diffusion occurs significantly (A in Figure 4).
Since the metal electrode (e) remains only on the side wall of the stepped portion of the barrier layer shown by , and the metal electrode (e) wiring is formed thereon, the barrier effect of the barrier layer is extremely improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a diode manufactured by implementing a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 2 is a process diagram of a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 3 is a process diagram of a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating the present invention in detail. FIG. wIJ5 is a diagram illustrating a method of manufacturing a semiconductor device according to the prior art. DESCRIPTION OF SYMBOLS 1-Reference silicon substrate, 2--Insulating film, 3-shaped φ/opening for electrode contact, 4--Polycrystalline silicon film, 5--φ/emitter region, 6--Fist metal film (contact layer), 700. Barrier layer, 8... Electrode/wiring film, 9... Electrode/wiring. 10---Silicon dioxide or silicon nitride film. Process diagram No. 35!3 Present invention ii figure

Claims (1)

[Claims] In a method for manufacturing a semiconductor device having a metal electrode/wiring (9) in which a barrier layer made of a film (7) of refractory metal nitride or the like is provided on the lower surface of an aluminum film (8). After forming the barrier layer made of the refractory metal nitride film (7), a silicon dioxide or silicon nitride film (10) is formed, and a different silicon dioxide or silicon nitride film (10) is formed. It is characterized by performing directional etching so that it remains only on the side wall of the step part of the barrier layer made of the refractory metal nitride film (7), and forming the metal electrode/wiring (9) thereon. A method for manufacturing a semiconductor device.