JPS61240659A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To suppress the occurrence of a malfunction due to the raised thick plasma nitride film as an interlayer insulating film or a passivation film by forming aluminum wirings, then forming a thin plasma nitride film, volatilizing moisture in aluminum by a heat treatment. CONSTITUTION:A thin plasma nitride film 2 of approx. 500-3,000Angstrom is formed by a plasma excitation in an atmosphere of approx. 300 deg.C containing SiH4 and NH3. Then, it is heat treated for 30min-1hr in atmosphere of 300-500 deg.C containing mainly N2. At this time the film 2 is reduced in the thickness to the degree that the moisture in the aluminum can be volatilized so that the moisture produced from the aluminum may not be enclosed between the plasma nitride film and the aluminum, thereby stopping the occurrence of a malfunction due to the raised plasma nitride film. Then, a thick plasma nitride film 3 of 5,000-10,000Angstrom is formed as an interlayer insulating film or a passivation film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and particularly to an interlayer film of an aluminum multilayer interconnection of a semiconductor integrated circuit device,
The present invention relates to a method for forming a plasma nitride film formed as a passivation film.

[Conventional technology]

Conventionally, atmospheric pressure CVDII film has been mainly used as an interlayer film for aluminum multilayer wiring, and atmospheric pressure CVDII film has been used. Consideration has been given to adopting a plasma nitride film, which has advantages over CVD films, such as superior etchability in the wiring step portion, dense structure, high mechanical strength, and resistance to moisture penetration. ing.

[Problem that the invention seeks to solve]

The plasma nitride film mentioned above has the property of not allowing moisture to penetrate, so it is effective against glaze defects caused by moisture entering semiconductor integrated circuit devices from the outside, such as wiring oven defects due to melting of aluminum wiring. It can be said that it is a membrane. However, impurities such as trace amounts of water are originally mixed into the aluminum film, and even in aluminum films formed by sputtering, which are said to contain relatively small amounts of impurities, these impurities are not completely removed. Therefore, if the plasma nitride film is applied to the surface of the aluminum wiring as an IHA passivation film with interlayer spacing, heat treatment in the subsequent process such as 45% of aluminum alloy etc.
When exposed to heat of about 0°C for about 30 minutes, moisture etc. outgassed from the aluminum is trapped between the plasma nitride film and the aluminum, causing the plasma nitride film to swell into a dome shape and even burst, resulting in defects. .

A schematic diagram of this defect is shown in FIG. For this reason, a method of performing heat treatment to outgas moisture etc. before forming the plasma nitride film was considered, but although it is effective against the above defects, the aluminum hillocks generated by the heat treatment at this time cause new It was found that this defect caused dielectric breakdown voltage failure.

[Means for Solving the Problems] The method for manufacturing a semiconductor device of the present invention includes a step of forming a wiring made of a thin film mainly made of aluminum on the surface of a semiconductor substrate, and a step of forming a thin film of 500 nm on the surface of the semiconductor substrate including the wiring. ~3
Deposit a plasma nitride film of about 0,001 to 300 to 500
A process of heat treatment at a temperature of about 30°C for about 1 hour, and a thick film of 50%
The process includes a step of depositing a plasma nitride film of about 0.00 to 10,000.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(C) are vertical cross-sectional views shown in order of steps to explain an embodiment of the present invention.

First, as shown in FIG. 1←), aluminum wiring 1 is formed by a conventional method.

Next, as shown in FIG. 1(1), a thin plasma nitride film 2 containing SiH4 and NH3 and having a thickness of about 500 to 3000 layers is formed by plasma excitation in an atmosphere of about 300 DEG C. and 0.1 to 2 torr. Next, 300 mainly based on N2
Heat treatment is performed in an atmosphere of about 30 to 500 degrees Celsius for about 30 minutes to one hour. At this time, since the plasma nitride film 2 described above is thin enough to allow moisture etc. in the aluminum to escape, moisture etc. outgassed from the aluminum will not be trapped between the plasma nitride film and the aluminum.
It is possible to prevent the occurrence of defects due to the above-mentioned swelling of the plasma nitride film. Furthermore, since the aluminum wiring is treated with the plasma nitride film 2, no hillocks occur during this heat treatment.

Next, as shown in FIG. 1C, a plasma nitride film 3 having a thickness of approximately 5,000 to 10,000 Å is grown in the same atmosphere as described above to form an interlayer insulating film or a substrate film.

〔Effect of the invention〕

As explained above, in the present invention, after forming aluminum wiring,
After applying a thin plasma nitride film, heat treatment is performed to release moisture in the aluminum. It is possible to suppress the occurrence of defects due to the swelling of the plasma nitride film even when the plasma nitride film is bulged, and also to suppress the occurrence of hillocks that cause a decrease in the dielectric strength voltage of the interlayer insulating film = 5
− It has the effect of:

[Brief explanation of the drawing]

FIGS. 1(a) to (C) are cross-sectional views shown in the order of steps to explain an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an aluminum multilayer wiring of a semiconductor device formed by a conventional method and having defects. It is a diagram. 1... Aluminum wiring, 2... Thin plasma nitride film, 3... Thick plasma nitride film,
4... Silicon substrate, 5... Plasma nitride film, 6... Aluminum wiring, 7...
...Plasma nitride film rupture location. 61f Lazuma-like u stomach research imm*f Kaya Z eyes 4hi Kawasara jam arrangement

Claims (1)

[Claims] A process of forming wiring made of a thin film mainly made of aluminum on the surface of a semiconductor substrate, and depositing a thin plasma nitride film of about 500 to 3000 Å on the surface of the semiconductor substrate including the wiring at a temperature of about 300 to 500°C for 30 minutes. A method for manufacturing a semiconductor device, comprising the steps of performing heat treatment for about 1 hour, and depositing a thick plasma nitride film of about 5000 to 10000 Å on the heat-treated thin plasma nitride film.