JPH08203896A - Fabrication of semiconductor device - Google Patents

Abstract

PURPOSE: To enhance the planarization on the surface of a wafer while stabilizing the resistance of a contact hole at a low value by filling the contact hole easily with a second metallization. CONSTITUTION: A first Al based alloy film 2 and an interlayer insulation film 4 are deposited sequentially on a semiconductor substrate, i.e., an interlayer insulation film 1, by a well known method. A contact hole 5 is then made through the interlayer insulation film 4 to expose a first Al based alloy film 2 on the bottom of the opening. Subsequently, the wafer is exposed to high temperature (25O deg.C) in a vacuum system in order to discharge gas from the interlayer insulation film 4 (a). The wafer is then cooled in the vacuum system (b). The cooling temperature is set at 50 deg.C or below. Finally, a nitride 7, a high melting point metal 6 and a second metal, i.e., a second A1 based alloy 3, are deposited sequentially in the contact hole 5 and exposed to high temperature (450 deg.C or above) thus filling the contact hole 5 with the second A1 based alloy 3.

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 semiconductor device, and more particularly to a technique for forming a metal wiring film.

[0002]

2. Description of the Related Art In recent years, due to higher integration and higher functionality of semiconductor devices, miniaturization of patterns has progressed, and accordingly, miniaturization of connection holes and increase of aspect ratio when forming metal wiring films have also progressed. I'm out. FIG. 4 is a sectional view showing the structure of a conventional semiconductor device. In FIG. 4, 1 is an interlayer insulating film as a semiconductor substrate, 2 is a first Al-based alloy film as a first metal wiring film, and 3 is a second A as a second metal wiring film.
1-based alloy film, 4 is an interlayer insulating film for separating the first Al-based alloy film 2 and the second Al-based alloy film 3, 5 is a connection hole opened in the interlayer insulating film 4, and 6 is a second Al A refractory metal film that is a base film of the system alloy film 3, and a nitride film 7 that is a base film between the second Al-based alloy film 3 and the refractory metal film 6.

A method of manufacturing a semiconductor device having such a structure will be described. First, a first Al-based alloy film 2 and an interlayer insulating film 4 are sequentially formed on the interlayer insulating film 1, and then a connection hole 5 is opened in the interlayer insulating film 4 to form the first Al-based alloy film 2. Expose part. After that, the wafer is heated to a high temperature (25
Exposed to 0 ° C or higher). After that, the refractory metal film 6, the nitride film 7, and the second Al-based alloy film 3 are sequentially formed, and the wafer is exposed to a high temperature (450 ° C. or higher) to form the second Al-based alloy in the connection hole 5. Embed the membrane 3. In addition, these processes are continuously processed in a vacuum apparatus, and then a predetermined process is performed to form a pattern.

[0004]

As described above, according to the conventional method of manufacturing a semiconductor device, after the second Al-based alloy film 3 is formed, it is exposed to a high temperature (450 ° C. or higher) to fill the connection hole 5. Although the reflow technique is used, in this conventional technique, there is variation in the filling of the second Al-based alloy film 3 in the connection hole 5, the flattening on the wafer surface is poor, and the connection hole 5 is used.
There is a problem that the resistance value is unstable and the resistance value is high and the reliability is insufficient. Therefore, improvement is desired.

That is, when the connection hole 5 is opened in the interlayer insulating film 4 and then the second Al-based alloy film 3 is formed, a high temperature ( However, if the temperature of this wafer is higher than that at the time of forming the second Al-based alloy film 3, the gas released from the interlayer insulating film 4 reacts with the second Al-based alloy film 3. However, the formation of an oxide or a nitride that inhibits the reflow and the inhibition of the reflow due to the grain growth of the second Al-based alloy film 3 occur.

The present invention has been made in order to solve the above-mentioned problems associated with the conventional example.
Of the metal wiring film can be easily embedded in the connection hole, the flatness on the wafer surface at that time can be improved, and the resistance value in the connection hole between the first metal wiring film and the second metal wiring film can be further improved. It is an object of the present invention to obtain a method for manufacturing a semiconductor device, which is stable and has low resistance.

[0007]

A method of manufacturing a semiconductor device according to the present invention comprises a first step of sequentially forming a first metal wiring film and an interlayer insulating film on a semiconductor substrate, and a step of forming the interlayer insulating film. A second step of opening the connection hole to expose the first metal wiring film at the bottom of the opening, and exposing the wafer that has undergone the second step to a high temperature in a vacuum apparatus to remove the first insulating film from the interlayer insulating film. A third step of releasing gas, and a fourth step of cooling the wafer that has undergone the third step in the vacuum apparatus,
The fifth step comprises sequentially forming a refractory metal film, a nitride film, and a second metal film in the connection hole in the vacuum device and exposing them to a high temperature.

In the fifth step, the formation of the refractory metal film and the nitride film is omitted and only the second metal wiring film is formed.

Further, the temperature in the third step is set to 250.
℃ or above and the temperature in the fifth step above the third
In contrast to the temperature of 450 ° C or higher, which is higher than the temperature in the process of
The temperature in the fourth step is set to 50 ° C. or lower.

[0010]

In the method of manufacturing a semiconductor device according to the present invention, the first metal wiring film and the interlayer insulating film are sequentially formed on the semiconductor substrate in the first step, and then the interlayer insulating film is formed in the second step. The connection hole is opened at the bottom of the opening and the first
Of the metal wiring film is exposed, and in the third step, the wafer is exposed to high temperature in a vacuum device to release gas from the interlayer insulating film, and then in the fourth step, the wafer is cooled in the vacuum device. When the second metal wiring film is formed by sequentially forming the refractory metal film, the nitride film, and the second metal film in the connection hole in the fifth step and exposing them to a high temperature, an interlayer insulating film is formed. After the gas is discharged from the substrate, it is sufficiently cooled to improve the embedding property of the second metal wiring film in the connection hole during reflow and the flatness of the wafer.

Further, the second metal wiring film is reflowed by omitting the formation of the refractory metal film and the nitride film and forming only the second metal wiring film in the fifth step. The reaction is sometimes avoided, and the resistance value at the interface between the connection hole and the first metal wiring film is low and stable.

Further, the temperature in the third step is set to 250.
℃ or above and the temperature in the fifth step above the third
In contrast to the temperature of 450 ° C or higher, which is higher than the temperature in the process of
By setting the temperature in the fourth step to 50 ° C. or lower, the gas released from the interlayer insulating film reacts with the second metal wiring film to form an oxide or a nitride that inhibits reflow, and It surely prevents the reflow from being hindered by the grain growth of the second metal wiring film.

[0013]

【Example】

Example 1. Hereinafter, the present invention will be described based on illustrated embodiments. First, a cross-sectional structure diagram of the semiconductor device according to the first embodiment of the present invention is similar to the conventional example shown in FIG. 4, but the manufacturing method is different. That is, FIG. 1 is a process diagram for explaining the method of manufacturing the semiconductor device according to the first embodiment, and mainly illustrates the temperature transition exposed to the wafer during processing in the vacuum apparatus. Hereinafter, a method for manufacturing the semiconductor device according to the first embodiment will be described with reference to the process chart shown in FIG.

First, a first Al-based alloy film 2 and an interlayer insulating film 4 as a first metal wiring film are sequentially formed on an interlayer insulating film 1 as a semiconductor substrate by a conventionally known method. After the step and the second step of opening the connection hole 5 in the interlayer insulating film 4 and exposing the first Al-based alloy film 2 at the bottom of the opening, the wafer is processed in the third step. Gas is released from the interlayer insulating film 4 by exposing it to a high temperature (250 ° C.) in a vacuum device (see FIG. 1A). At this time, if the temperature of this wafer is higher than that at the time of forming the second Al-based alloy film 3 described later, the gas emitted from the interlayer insulating film 4 and the second
The Al-based alloy film 3 reacts to form an oxide or a nitride that inhibits the reflow, and the grain growth of the second Al-based alloy film 3 inhibits the reflow. The temperature for releasing is the second Al-based alloy film 3
The temperature is lower than that during formation of.

Then, in a fourth step, the wafer is cooled in a vacuum device (see FIG. 1 (b)). At this time, as described above, the wafer is exposed to a high temperature (250 ° C. or higher) to discharge gas from the interlayer insulating film 4 by the vacuum device. However, the temperature of this wafer is high when the second Al-based alloy film 3 is formed. When the temperature is higher, the formation of oxides or nitrides that inhibit reflow and the inhibition of reflow due to grain growth of the second Al-based alloy film 3 occur. Therefore, it is necessary to sufficiently cool the cooling temperature. It shall be 50 ° C or lower.

Next, in the fifth step, the nitride film 7, the refractory metal film 6 and the second metal A as a second metal film are formed in the connection hole 5.
The 1-based alloy film 3 is sequentially formed, and the second Al-based alloy film 3 is embedded in the connection hole 5 by exposing it to a high temperature (450 ° C. or higher) (see FIG. 1C). After cooling the wafer sufficiently,
The second Al-based alloy film 3 is formed, and then the wafer is exposed to a high temperature (450 ° C. or higher) to fill the connection hole 5 with the second Al-based alloy film 3, which is continuously processed in a vacuum apparatus. . After that, a predetermined process is performed to form a pattern.

In this way, when the second Al-based alloy film 3 is formed, the second metal wiring film to the connection hole at the time of reflow is sufficiently cooled after the gas is released from the interlayer insulating film. And the flattening of the wafer are achieved. Further, the gas emitted from the interlayer insulating film 4 and the second A
It is possible to reliably prevent the reaction of the 1-based alloy film 3 from forming an oxide or a nitride that inhibits the reflow and the inhibition of the reflow due to the grain growth of the second Al-based alloy film 3.

Example 2. Next, FIG. 2 relates to a method of manufacturing a semiconductor device in which the formation of the refractory metal film 6 and the nitride film 7 is omitted, and is a process diagram illustrating a temperature transition exposed to a wafer during processing in a vacuum device corresponding to FIG. FIG. 3 is a sectional structural view of a semiconductor device obtained through the steps shown in FIG.

That is, in the second embodiment, in the sectional view of the semiconductor device shown in FIG. 4, after the connection hole 5 is opened in the interlayer insulating film 4, the wafer is heated to a high temperature (250 ° C. or higher) in the vacuum device as in the prior art. 2) to remove gas from the interlayer insulating film 4 (see FIG. 2A), and after sufficiently cooling the wafer (50 ° C. or lower) (see FIG. 2B), FIG.
As shown in the cross-sectional structure diagram of 1, the formation of the refractory metal film 6 and the nitride film 7 is omitted, and only the second Al-based alloy film 3 is formed. Then, after the second Al-based alloy film 3 is formed, the wafer is exposed to high temperature (450 ° C. or higher), and the second Al-based alloy film 3 is embedded in the connection hole 5 (see FIG. 2C). Incidentally, this is continuously processed in a vacuum apparatus. Then, a predetermined process is performed to form a pattern.

Thus, the refractory metal film 6 and the nitride film 7 are
By omitting these, it is possible to avoid reacting these with the second Al-based alloy film 3 at the time of reflow, and to prevent the connection hole 5 and the first A
The resistance value at the interface of the l-based alloy film 2 becomes low, and a stable low resistance ohmic contact can be obtained.

Example 3. Although the second Al-based alloy film has been described in the above-mentioned first and second embodiments, when a multilayer wiring is used, the third and fourth and higher-layer Al-based alloy films may be used.
As a matter of course, the same effect as that of the above-mentioned embodiment is obtained.

[0022]

As described above, according to the method of manufacturing the semiconductor device of the present invention, after the first metal wiring film and the interlayer insulating film are sequentially formed on the semiconductor substrate in the first step, Two
Step, a connection hole is opened in the interlayer insulating film to expose the first metal wiring film at the bottom of the opening, and in the third step, the wafer is exposed to a high temperature in a vacuum apparatus. Gas is discharged from the substrate, then the wafer is cooled in the vacuum device in the fourth step, and a refractory metal film, a nitride film, and a second metal film are sequentially formed in the connection hole in the fifth step. When the second metal wiring film is formed by exposing the film to the film and exposing it to a high temperature, sufficient cooling is performed after gas is released from the interlayer insulating film. There is an effect that the embedding property and the flattening of the wafer are improved.

In the fifth step, the formation of the refractory metal film and the nitride film is omitted and only the second metal wiring film is formed, so that the second metal wiring film is reflowed. It is possible to avoid reacting at times and to make the resistance value at the interface between the connection hole and the first metal wiring film low and stable.

Further, the temperature in the third step is set to 250.
℃ or above and the temperature in the fifth step above the third
In contrast to the temperature of 450 ° C or higher, which is higher than the temperature in the process of
By setting the temperature in the fourth step to 50 ° C. or lower, the gas released from the interlayer insulating film reacts with the second metal wiring film to form an oxide or a nitride that inhibits reflow, and It is possible to reliably prevent the reflow from being hindered by the grain growth of the second metal wiring film.

[Brief description of drawings]

FIG. 1 is a process diagram for explaining a method for manufacturing a semiconductor device according to a first embodiment of the present invention, which is a process flow diagram mainly explaining a temperature transition exposed to a wafer during processing in a vacuum device.

FIG. 2 is a process chart for explaining the method for manufacturing the semiconductor device according to the second embodiment of the present invention, which is a process flow diagram mainly explaining the temperature transition exposed to the wafer during the processing in the vacuum apparatus.

FIG. 3 is a sectional structural view of a semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a sectional structural view showing a semiconductor device according to the related art and Embodiment 1 of the present invention.

[Explanation of symbols]

1 interlayer insulating film, 2 1st Al type alloy film, 3 2nd Al type alloy film, 4 interlayer insulating film, 5 connection hole, 6 refractory metal film, 7 nitride film.

Claims (3)

[Claims] 1. A first step of sequentially forming a first metal wiring film and an interlayer insulating film on a semiconductor substrate, and a connecting hole is opened in the interlayer insulating film, and the first hole is formed at the bottom of the opening. Second step of exposing the metal wiring film of the above step, a third step of exposing the wafer that has undergone the second step to a high temperature in a vacuum device to release gas from the interlayer insulating film, and a vacuum step in the vacuum device. A fourth step of cooling the wafer which has undergone the third step, and a fifth step of sequentially forming a refractory metal film, a nitride film and a second metal film in the connection hole in the vacuum device and exposing them to a high temperature. And a method of manufacturing a semiconductor device. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the formation of the refractory metal and the nitride film is omitted in the fifth step, and only the second metal wiring film is formed. . 3. The temperature in the third step is set to 250 ° C. or higher, and the temperature in the fifth step is set to 450 ° C. or higher, which is higher than the temperature in the third step. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the temperature in step 4 is set to 50 [deg.] C. or lower.