JPH08148487A - Manufacturing method of metal wiring - Google Patents

Abstract

(57) [Summary] [Structure] When forming a metal wiring having an Al or Al alloy film as a main component on a semiconductor substrate having an insulating film, the semiconductor substrate is heated to 200 ° C. or higher and then the semiconductor substrate is heated to 150 ° C. When the semiconductor substrate is cooled to below, and then an Al or Al alloy film is vapor-deposited, or when metal wiring having an Al or Al alloy film as a main component is formed on the semiconductor substrate having an insulating film, Al or Al in the state
The vapor deposition of the alloy film is started, the temperature of the semiconductor substrate is raised to a temperature of 200 ° C. or higher with the vapor deposition, and the vapor deposition is terminated when the temperature of the semiconductor substrate is 200 ° C. or higher. [Effect] At the same time as removing the moisture adhering to the substrate
Since a film having a high (111) orientation of Al can be obtained, a metal wiring having a long electromigration life can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal wiring of a semiconductor device, and more particularly to a metal wiring having a face-centered cubic lattice represented by Al or an Al alloy film as a main constituent. The present invention provides a method for forming a highly reliable metal wiring having higher electromigration resistance.

[0002]

2. Description of the Related Art In recent years, with metal wiring in semiconductor devices, the density of current flowing through the wiring has increased with miniaturization.
There is a problem that the electromigration life is shortened. In a metal wiring of a semiconductor device, wiring having Al or an Al alloy film as a main constituent element is widely used. However, when the above Al or Al alloy film is deposited, it causes deterioration of electromigration life. In order to remove moisture adsorbed on the semiconductor substrate,
In order to increase the grain size of the semiconductor substrate, it is common practice to heat the semiconductor substrate to 200 ° C. or higher and then perform sputter deposition or vapor deposition.

In addition, in recent years, the electromigration life of a wiring mainly composed of Al or an Al alloy film is Al.
It is reported that the (111) plane is proportional to the square of the half-width of the rocking curve in the direction perpendicular to the substrate. (For example, H. Toyoda et al. 32th IRPS pp.178-184 (1994))
That is, in order to improve the electromigration life of the wiring having Al or Al alloy film as a main component,
It is known that the full width at half maximum of the rocking curve of the Al (111) plane in the direction perpendicular to the substrate should be reduced.

[0004]

However, as a result of our experiment, the Al alloy film sputter-deposited after heating the semiconductor substrate to 200 ° C. or higher is perpendicular to the substrate of the Al (111) plane as shown in FIG. Since the rocking curve in two directions is divided into two, the full width at half maximum of the semiconductor substrate is 150 ° C when viewed as a whole.
It has been found that the temperature becomes higher than that of the Al alloy film sputter-deposited at the following temperature, which may deteriorate the electromigration life. Similar experimental results have been observed for Al films obtained by the vapor deposition method (eg M. Tsukada and S. Ohfuji, J.
ournal of the Vacuum Science Technology, B11, pp.3
26-332 (1993)), it is considered that this phenomenon is common to the sputter vapor deposition method and the vapor deposition method.

In view of the above problems, the present invention provides a method for manufacturing a semiconductor device having highly reliable metal wiring having high electromigration resistance without impairing the effect of removing moisture and the like adsorbed on a semiconductor substrate. To do.

[0006]

In order to solve the above problems, a method of manufacturing a metal wiring of a semiconductor device according to the present invention is a metal having an Al or Al alloy film as a main constituent element on a semiconductor substrate having an insulating film. When forming the wiring, the semiconductor substrate is heated to 200 ° C. or higher, cooled to 150 ° C. or lower, and then an Al or Al alloy film is deposited.

Further, according to the method of manufacturing a metal wiring of a semiconductor device of the present invention, when the metal wiring having Al or Al alloy film as a main constituent element is formed on the semiconductor substrate having the insulating film, the semiconductor substrate has a temperature of 150 ° C. or lower. Starting the vapor deposition of Al or Al alloy film in the state of
When the temperature of the semiconductor substrate is raised to 20 ° C.
The vapor deposition is completed at a temperature of 0 ° C. or higher.

[0008]

When a metal film mainly composed of Al or an Al alloy film is sputter-deposited or sputtered, the semiconductor substrate is heated to 200 ° C. or higher and then cooled to 150 ° C. or lower, and then the Al or Al alloy film is sputtered. Evaporation or vapor deposition, or starting the deposition at a temperature of 150 ° C. or lower and ending the deposition at a temperature of 200 ° C. or higher
By sputter-depositing or vapor-depositing an Al or Al alloy film, moisture adsorbed on the semiconductor substrate can be removed, and since the deposition is started at a temperature of 150 ° C. or less, the orientation is impaired. Nor.

[0009]

EXAMPLE A method of forming a metal wiring of a semiconductor device according to an example of the present invention will be described below.

First, the Al-1% Si-0.5% Cu alloy was formed by changing the substrate heating temperature on a semiconductor substrate in which a BPSG film was deposited on a Si substrate.
FIG. 4 shows the result of measuring the rocking curve of the Al (111) surface in the direction perpendicular to the substrate after depositing 500 nm. The experiment was conducted under four conditions of heating temperature of the substrate: 100 ° C., 150 ° C., 200 ° C., and 300 ° C.

As is apparent from FIG. 4, only one peak is seen as a rocking curve perpendicular to the substrate up to 150 ° C., but at 200 ° C. or higher, the peak is divided into two peaks each inclined by about 4 degrees from the substrate. ing.

Here, even when the peak of the rocking curve of the Al (111) plane in the direction perpendicular to the substrate is divided into two peaks, the peak is regarded as one as a whole,
Substrate heating temperature is about 7 degrees at 100 ° C and about 13 degrees at 150 ° C.
The temperature is about 15 degrees at 200 ° C. and about 14.4 degrees at 300 ° C. Although not shown in FIG. 4, when the Al-1% Si-0.5% Cu alloy was deposited without heating the substrate, the half width was about 8 degrees. Therefore, it can be seen that the orientation of Al (111) deteriorates significantly at around 150 to 200 ° C. In addition,
This temperature corresponds approximately to 2/3 of the melting point of Al.

In addition, it is generally known that a film sputter-deposited at a temperature of ⅔ or more of the melting point moves actively on the surface of the sputtered substrate and promotes recrystallization. (For example JA Thornton, Journal of the Vacuum S
cience Technology, 12, pp.830-835 (1975)) Al film is a kind of metal with face-centered cubic lattice, and metal or metal alloy film with face-centered cubic lattice is formed by sputter deposition or vapor deposition. It is known to be oriented in the (111) plane. Therefore, if a metal or metal alloy film having a face-centered cubic lattice is sputter-deposited or vapor-deposited at a temperature of ⅔ or more of the melting point, the orientation of the (111) plane will decrease and the electromigration characteristics will deteriorate when processed into wiring. To be

(Embodiment 1) A method for manufacturing a metal wiring of a semiconductor device according to a first embodiment of the present invention will be described below with reference to the drawings.

A semiconductor substrate having an insulating film deposited on a Si substrate is introduced into a sputtering apparatus and heated at 200 ° C. in vacuum to remove moisture adhering to the substrate. Next, cool the above semiconductor substrate to room temperature in the same sputtering device and
% Si-0.5% Cu alloy is deposited, and then patterned by a normal photolithography method to form a metal wiring.

Al (1) of Al wiring formed as described above
The rocking curve of 11) plane is shown in Fig. 1, while the rocking curve of Al (111) plane of Al wiring when Al-1% Si-0.5% Cu alloy is deposited at 200 ℃ without cooling the semiconductor substrate. Is shown in FIG.

As is clear from FIG. 1, the rocking curve in this embodiment shows a single peak type with a half value width of about 8 degrees, and the semiconductor substrate shown in FIG.
The half-width is smaller than that when the Al-1% Si-0.5% Cu alloy is deposited, and the Al (111) orientation is high.

Therefore, according to the method for manufacturing a metal wiring of a semiconductor device obtained in this embodiment, a wiring having a high Al (111) orientation and a long electromigration life can be obtained.

In this example, Al-1% Si- was used as the Al alloy.
Although 0.5% Cu alloy was used, Al or Al alloy may be used instead. Further, although the wiring of the Al alloy single layer is formed in this embodiment, the wiring may be formed by laminating with another metal film such as TiW, W only on the upper and lower sides of the Al alloy, or only on the lower side.

Further, in this embodiment, the Al alloy, which is a face-centered cubic lattice, is used as the metal. However, when a metal or a metal alloy film having a face-centered cubic lattice is used, the semiconductor substrate has a melting point of 2 / 2/3 of melting point after heating above 3
The same effect can be obtained by sputter-depositing or vapor-depositing a metal or metal alloy film after cooling to a temperature of or below.

At this time, above and below the metal or metal alloy film,
The wiring may be formed only by laminating it with another metal film such as TiW or W only on the upper side or the lower side.

(Embodiment 2) A method for forming metal wiring of a semiconductor device according to a second embodiment of the present invention will be described below.

A semiconductor substrate having an insulating film deposited on a Si substrate is introduced into a sputtering apparatus, and an Al-1% Si-0.5% Cu alloy is deposited while raising the substrate temperature from room temperature to 200 ° C. in vacuum. That is, the deposition is started at room temperature, which is a temperature of 150 ° C. or lower, and the Al-1% Si-0.5% Cu alloy is deposited while increasing the temperature. As a result, the moisture adhering to the substrate can be removed to some extent and the grain size of Al can be increased.
Then, patterning is performed by a normal photolithography method to form a metal wiring.

In the Al wiring thus formed, the rocking curve of the Al (111) plane has a half value width of about 11.
It shows a single-peak type of 5 degrees and has a half-value width smaller than that of the case of depositing an Al-1% Si-0.5% Cu alloy at 200 ° C without cooling the semiconductor substrate (Fig. 3), and has an Al (111) orientation Is high.

Therefore, also in the method for manufacturing the metal wiring of the semiconductor device obtained in this embodiment, a wiring having a high Al (111) orientation and a long electromigration life can be obtained.

In this example, Al-1% Si- was used as the Al alloy.
Although 0.5% Cu alloy was used, Al or Al alloy may be used instead. Further, although the wiring of the Al alloy single layer is formed in this embodiment, the wiring may be formed by laminating with another metal film such as TiW, W only on the upper and lower sides of the Al alloy, or only on the lower side.

Further, in this embodiment, the Al alloy which is the face-centered cubic lattice is used as the metal, but when the metal or the metal alloy film having the face-centered cubic lattice is used, the semiconductor substrate is set to the melting point of the metal of 2 / 2/3 of melting point after heating above 3
The same effect can be obtained by sputter-depositing or vapor-depositing a metal or metal alloy film after cooling to a temperature of or below.

[0028]

As described above, according to the present invention, when a metal film mainly composed of Al or an Al alloy film is sputter-deposited or vapor-deposited, after heating the semiconductor substrate to 200 ° C. or higher, 1
After cooling to 50 ° C. or lower, an Al or Al alloy film is sputter-deposited or vapor-deposited, or the semiconductor substrate is made 150
At least Al or at least Al or Al alloy film is sputter-deposited or vapor-deposited so as to start the deposition at a temperature of ℃ or less and finish the deposition at a temperature of 200 ℃ or more.
Since the temperature at which the Al alloy film is sputter-deposited or vapor-deposited is 150 ° C. or lower, the Al (111) orientation is improved,
The electromigration resistance of the metal wiring of the semiconductor device can be improved.

Further, according to the present invention, even when a metal or a metal alloy film having a face-centered cubic lattice is sputter-deposited or vapor-deposited, the semiconductor substrate is heated to a temperature not lower than ⅔ of the melting point of the metal and then the melting point of After cooling to a temperature of 3 or less, the metal or metal alloy film is sputter-deposited or vapor-deposited, or the semiconductor substrate is started to be deposited at a temperature of 2/3 or less of the melting point of the metal, and then 2/3 of the melting point. By completing the deposition at a temperature equal to or higher than the temperature of (1), the (111) orientation of the metal having the face-centered cubic lattice can be improved, and the electromigration resistance of the metal wiring of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a rocking curve showing (111) orientation of an Al alloy formed by a method for manufacturing a metal wiring of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a rocking curve showing (111) orientation of an Al alloy film formed by a method for manufacturing a metal wiring of a semiconductor device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a rocking curve showing the (111) orientation of an Al alloy film formed by a conventional method for manufacturing a metal wiring of a semiconductor device.

FIG. 4 is a diagram showing substrate heating temperature dependence of a rocking curve showing Al (111) orientation of Al-1% Si-0.5% Cu film.

Claims (4)

[Claims] 1. Al or Al on a semiconductor substrate having an insulating film.
A method of manufacturing a metal wiring, the method comprising: forming a metal wiring having an alloy film as a main component; a semiconductor substrate heating step of heating the semiconductor substrate to 200 ° C. or higher; A method of manufacturing a metal wiring, comprising: a semiconductor substrate cooling step of cooling to not more than ° C; and a vapor deposition step of vapor depositing an Al or Al alloy film after the semiconductor substrate cooling step. 2. Al or Al on a semiconductor substrate having an insulating film.
A method of manufacturing a metal wiring, wherein a metal wiring having an alloy film as a main component is formed, wherein vapor deposition of Al or an Al alloy film is started in a state where the semiconductor substrate is at 150 ° C or lower, and the vapor deposition of the semiconductor substrate A method for producing metal wiring, wherein the temperature is raised to a temperature of 200 ° C. or higher, and the vapor deposition is completed when the temperature of the semiconductor substrate is 200 ° C. or higher. 3. A method of manufacturing a metal wiring, comprising forming a metal wiring of a metal having a face-centered cubic lattice structure on a semiconductor substrate having an insulating film, wherein the semiconductor substrate has a melting point of 2 of the metal.
A semiconductor substrate heating step of heating to a temperature of ⅓ or more, a semiconductor substrate cooling step of cooling to a temperature of ⅔ or less of the melting point of the metal after the semiconductor substrate heating step, and the metal after the semiconductor substrate cooling step. And a vapor deposition step of vapor-depositing. 4. A method of manufacturing a metal wiring, comprising forming a metal wiring of a metal having a face-centered cubic lattice structure on a semiconductor substrate having an insulating film, wherein the semiconductor substrate has a melting point of 2 of the metal.
Vapor deposition of the metal is started at a temperature of ⅓ or less, and the temperature of the semiconductor substrate is set to ⅔ of the melting point of the metal together with the vapor deposition.
A method of manufacturing a metal wiring, which comprises raising the temperature to the above temperature and ending the vapor deposition at a temperature of the semiconductor substrate being ⅔ or more of a melting point of the metal.