JPH10189590A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor device which is enhanced in reliability, by a method wherein an insulating film formed on a semiconductor substrate where an Cu film wiring is provided is protected against cracking and dents. SOLUTION: A semiconductor device is equipped with a semiconductor substrate 1, a first insulating film 2 which is provided with an opening 4 and formed on the substrate 1, a conductive film 5 which covers the inner wall of the opening 4, and a Cu film wiring 61 embedded in the opening 4. The Cu film wiring 61 is formed by making its upper edge protrude from the surface of the first insulating film 2, and the upper edge of the Cu film wiring 61 is covered with a second insulating film 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a Cu film wiring and a method of manufacturing the same.

[0002]

2. Description of the Related Art As high integration and high speed of semiconductor devices are required, wiring widths and wiring intervals are becoming finer.
By the way, as a wiring material of a semiconductor device, A
l (aluminum) films have been widely used. But,
As the miniaturization of wiring progresses, problems with respect to the electromigration resistance and stress migration resistance of the Al film and the problem of signal delay due to an increase in wiring resistance have arisen. Under such circumstances, instead of the Al film,
Cu (copper) films having excellent electromigration resistance and low resistance have been used as wiring materials.

However, Cu has a problem that it is difficult to perform fine processing because the vapor pressure of its halide is low and it cannot be etched by RIE at a low temperature like Al. Therefore, conventionally, C
As a method of forming a u film wiring, an insulating film having an opening is formed on a semiconductor substrate, Cu is buried in the opening, and then the surface is flattened by a chemical mechanical polishing method to form a Cu film wiring. The method has been taken. Hereinafter, the details of the conventional Cu film wiring formed in this way and the method of forming the same will be described.

FIGS. 26 to 32 are sectional views of a semiconductor device showing a conventional method of forming a Cu film wiring in the order of steps. First,
As shown in FIG. 26, a first insulating film 2 made of a silicon oxide film is formed on a semiconductor substrate 1 made of silicon to a thickness of about 1 μm by a CVD method or the like. Next, as shown in FIG. 27, a resist film is formed on the first insulating film 2 and then patterned by photolithography to form a resist pattern 3. Next, as shown in FIG. 28, an opening 4 is formed in the first insulating film 2 to have a width of about 0.3 μm and a depth of about 0.6 μm by dry etching using the resist pattern 3 as a mask.

Thereafter, the resist pattern 3 is removed, and as shown in FIG. 29, a conductive film 5, for example, having a thickness of 0.05 μm
A TiN film is formed on the surface of the first insulating film 2 including the opening 4 by a sputtering method or a CVD method. Then
As shown in FIG. 30, a Cu film 6 is formed to a thickness of about 0.5 μm by a similar method so as to fill the inside of the opening 4 of the first insulating film 2. The TiN film is generally provided for the purpose of preventing mutual diffusion of Cu and silicon. Next, as shown in FIG. 31, the T of the flat portion on the insulating film 2 is formed by a chemical mechanical polishing method.
The iN film 5 and the Cu film 6 are removed. Through these steps, the opening 4 provided in the insulating film 2 as shown in FIG.
The semiconductor device having the Cu film wiring 60 embedded in the inside of the semiconductor device is formed.

[0006]

The conventional semiconductor device is formed as described above. As shown in FIG.
The structure is such that the upper part of the u film wiring 60 is flat with respect to the surface of the insulating film 2. Therefore, when the unnecessary portions of the Cu film 6 and the TiN film 5 are removed by the chemical mechanical polishing method shown in FIG. 31, this polishing must be performed until the first insulating film 2 is exposed. For this reason, after the TiN film 5 is polished, a part of the first insulating film 2 is also polished at the same time.
As shown in FIG. 1, there is a problem that a scratch (scratch) is formed on the surface of the first insulating film 2. When such a scratch is formed, Cu or TiN remains in that portion, unnecessarily shorting the wiring, and affecting the reliability of the semiconductor device.

In the conventional semiconductor device, when unnecessary portions of the TiN film 5 and the Cu film 6 are removed by a chemical mechanical polishing method, as shown in FIG. Are easily formed. When such a depression is formed in the semiconductor device, Cu
There is a problem that the height of the film wiring becomes relatively low, and as a result, the wiring resistance of that portion increases. Furthermore, the conventional semiconductor device has a problem that the Cu film wiring is easily oxidized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made to prevent a crack or a dent from occurring in an insulating film on a semiconductor substrate, and to provide a highly reliable semiconductor device and a method of manufacturing the same. It is intended to provide.

Another object of the present invention is to provide a semiconductor device provided with a Cu film wiring having excellent oxidation resistance.

[0010]

A semiconductor device according to the present invention is formed by embedding a semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, and embedding the inside of the opening of the insulating film. In the semiconductor device provided with the Cu film wiring, the upper end of the Cu film wiring protrudes from the surface of the insulating film.

Further, a semiconductor device according to the present invention includes a semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, a conductive film covering an inner wall of the opening of the insulating film, In a semiconductor device having a Cu film wiring formed by being embedded in an opening, an upper end portion of the Cu film wiring projects from the surface of the insulating film.

Further, in the semiconductor device according to the present invention, of the conductive film covering the inner wall of the opening of the insulating film, the thickness of the conductive film formed on the side wall of the opening is smaller than the bottom of the opening. The thickness is smaller than the thickness of the conductive film formed in the portion.

Further, in the semiconductor device according to the present invention, the upper end portion of the Cu film wiring projecting from the surface of the insulating film formed on the semiconductor substrate is covered with a silicon oxide film.

Further, in the semiconductor device according to the present invention, the upper end of the Cu film wiring projecting from the surface of the insulating film is covered with a silicon nitride film.

According to another aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; an insulating film formed on the semiconductor substrate and having an opening; a conductive film covering a bottom surface of the opening; In a semiconductor device provided with a Cu film wiring formed by being embedded in a semiconductor device, an upper end portion of the Cu film wiring is formed so as to protrude from a surface of the insulating film. Is covered with a silicon nitride film.

According to another aspect of the present invention, there is provided a semiconductor device, a semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, a conductive film covering a bottom surface of the opening, and an inner portion of the opening. In a semiconductor device provided with a Cu film wiring formed by being embedded in a semiconductor device, an upper end portion of the Cu film wiring is formed so as to protrude from a surface of the insulating film. Is covered with an Al film.

Further, in the semiconductor device according to the present invention, the conductive film covering the opening of the insulating film is made of any one of a titanium nitride film, a titanium silicon nitride film and an aluminum alloy film.

Further, according to a method of manufacturing a semiconductor device according to the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and an insulating film including an inner wall portion of the opening Forming a conductive film on the conductive film, forming a Cu film on the conductive film, and polishing the Cu film so that the conductive film on the flat portion of the insulating film remains. Removing the conductive film remaining on the flat portion of the insulating film.

Further, according to a method of manufacturing a semiconductor device of the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and an insulating film including an inner wall of the opening A conductive film is formed on the insulating film so that the thickness of the conductive film formed on the side wall of the opening of the insulating film is smaller than the thickness of the conductive film formed on the flat portion of the insulating film. Forming a Cu film on the conductive film; polishing the Cu film so that the conductive film remains on a flat portion of the insulating film; Removing the conductive film remaining on the flat portion.

Further, in the method of manufacturing a semiconductor device according to the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming a first conductive film on the insulating film, and a step of forming the first conductive film Forming an opening in the insulating film through the conductive film; and forming a second conductive film on the inner wall of the opening and the first conductive film.
Forming a Cu film on the second conductive film, forming a Cu film on the second conductive film, and forming the first conductive film on at least a flat portion of the insulating film. Polishing the Cu film, and removing the first conductive film remaining on the flat portion of the insulating film and the second conductive film on the surface of the first conductive film. It is meant to be included.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a semiconductor substrate made of a silicon substrate, and 2 denotes a first substrate made of a silicon oxide film formed on the semiconductor substrate 1.
4, an opening formed in the first insulating film, 5 a conductive film made of TiN (titanium nitride) formed so as to cover the inner wall of the opening 4, and 61 a conductive film 5 Cu embedded in the opening 4 of the exposed insulating film 2 and formed so that the upper end protrudes from the surface of the first insulating film 2
The (copper) film wiring 7 is provided on the surface of the first insulating film 2 and on the first
Is a second insulating film made of a silicon oxide film formed so as to cover the upper end of the Cu film wiring 61 projecting from the surface of the insulating film 2.

Next, a method of manufacturing the semiconductor device thus configured will be described with reference to FIGS. First, as shown in FIG. 2, the surface of a semiconductor substrate 1 made of a silicon substrate is formed by thermal CVD, plasma CVD, or the like.
The first insulating film 2 is formed by depositing a silicon oxide film with a thickness of about 1 μm. Then, as shown in FIG.
A resist film is formed on the surface of the first insulating film 2 and patterned by photolithography to form a resist pattern 3. Next, as shown in FIG. 4, anisotropic dry etching is performed using the resist pattern 3 as a mask to form a groove-shaped opening 4 having a width of about 0.3 μm and a depth of about 0.5 μm in the first insulating film 2. Form.

Next, after removing the resist pattern 3,
As shown in FIG. 5, a conductive film 5, for example, a TiN film is formed on the surface of the first insulating film 2 including the inner wall of the opening 4.
Here, of the conductive film 5, the portion of the conductive film 5 b formed on the side wall of the opening 4 has a flat portion of the first insulating film 2, that is, the opening 4 of the insulating film 2 is formed. The conductive film 5a is formed so as to be thinner than the thickness of the conductive film 5a formed on the surface of the non-formed portion. For example, assuming that the thickness of the conductive film 5a formed on the flat portion of the insulating film 2 is 0.2 μm, the thickness of the conductive film 5b formed on the side wall of the opening 4 is 5% to 10% thereof. That is, it is formed so as to be 0.01 μm to 0.02 μm.

Such a conductive film 5 can be formed by a directional sputtering method such as a collimation sputtering method, a long distance sputtering method, an ionization sputtering method, or a plasma CVD method. In general, when a conductive film is formed by such a directional sputtering method, the thickness of the conductive film formed on the side wall of the opening 4 is smaller than that of the conductive film formed on the bottom of the opening 4. It becomes thinner than the film. Further, the material of the conductive film 5 needs to be a material having an etching characteristic different from that of the Cu film 6 to be formed later, that is, a material that can be selectively etched with Cu.
In addition to the film, a film made of a compound of Ti, silicon, and nitrogen is used. Further, an aluminum alloy film which can be easily etched by chlorine may be used.

Next, as shown in FIG. 6, the Cu film 6 is formed by sputtering or CVD so as to fill the inside of the opening 4 whose inner wall is covered with the conductive film 5 and to have a thickness. The first conductive film 5 is formed to have a thickness of about 0.4 μm on the surface. The Cu film 6 formed here is not limited to pure Cu, but may be another film containing Cu as a main component and capable of being selectively etched with the first conductive film 5. For example,
The same applies to Cu containing other metals such as Al (aluminum) and Ti (titanium) in a trace amount of about 1%.

Next, as shown in FIG. 7, the surface of the Cu film 6 is polished by a chemical mechanical polishing method to form a Cu film wiring 61. Here, the polishing of the Cu film 6 is performed by the first insulating film 2.
The operation is performed so that the Cu film on the conductive film 5a formed on the flat portion is completely removed and the underlying conductive film 5a remains. That is, by this polishing, the conductive film 5a on the flat portion of the insulating film 2 is exposed, and is slightly, for example, 0.05 μm.
m is removed, but is not completely removed and remains on the first insulating film 2. Therefore, the Cu film wiring 61 formed in this step is flat not on the surface of the flat portion of the first insulating film 2 but on the surface of the remaining conductive film 5a as shown in FIG. It is formed so that it becomes.

Next, as shown in FIG. 9, the first conductive film 5a remaining on the flat portion of the first insulating film 2 is selectively removed by dry etching. However, this etching is performed so that a portion of the conductive film 5 that covers the inner wall of the opening 4 of the insulating film 2 remains. Such etching conditions include, for example, the conductive film 5
When the material is TiN, etching is performed at a relatively low temperature of several degrees C. to several tens degrees C. using a gas containing chlorine as an etching gas. By this etching step, as shown in FIG. 9, the Cu film 61 is formed with its upper end protruding from the surface of the insulating film 2 by the thickness of the remaining conductive film 5a. In this etching step, the conductive film 5b on the side wall of the opening 4 has the same height as the flat portion of the first insulating film 2 or is slightly lowered by over-etching.

Next, a second insulating film 7, for example, a silicon oxide film having a thickness of 0.8 μm, covers the first insulating film 2 and the upper end of the Cu film wiring 61 by a thermal CVD method or a plasma CVD method. It is formed as follows. Through these steps, a semiconductor device having a configuration as shown in FIG. 1 is obtained.

The semiconductor device formed as described above
In the step of forming the Cu film wiring 61 by polishing, the polishing is not performed until the Cu film 6 becomes flat with respect to the surface of the first insulating film 2, and the Cu film 6 is projected on the surface of the insulating film 2. Polishing has been completed. Therefore, polishing is not performed until the insulating film 2 is exposed, and the surface of the insulating film 2 is not directly polished. As a result, no scratch or depression is formed on the surface.

In other words, the conductive film 5a remaining on the flat portion of the insulating film 2 always acts as a protective film for the insulating film 2 in the polishing process. As a result, the conventional problems that the wiring is short-circuited by Cu or TiN remaining in the scratch on the insulating film 2 and the resistance of the Cu film wiring increases are avoided.

In the above semiconductor device, when the conductive film 5 is formed, the thickness of the conductive film 5a formed on the flat portion of the insulating film 2 is larger than the thickness of the conductive film 5a formed on the side wall of the opening 4. Although the thickness of the conductive film 5b is set to be small, the above-described effect can be obtained even when the thickness of the conductive film 5b in the side wall portion is the same as the thickness of the conductive film 5a in the flat portion. Can be demonstrated. However, the width of the Cu film wiring 61 formed inside the opening 4 of the insulating film 2 is reduced by the thickness of the first conductive film 5b formed on the side wall of the opening 4. On the other hand, in order for the conductive film 5a to function as a protective film for the insulating film 2 in the polishing step, it is necessary to form the conductive film 5a to a certain thickness. Therefore, when the conductive film 5a is formed thick, if the conductive film 5b formed on the side wall of the opening 4 is formed to have the same thickness as the conductive film 5a, the width of the Cu film wiring 61 is reduced. The decrease is large, and the wiring resistance is increased.

Therefore, in the semiconductor device described above, the thickness of the conductive film 5b formed on the side wall of the opening 4 is smaller than the thickness of the conductive film 5a formed on the flat portion of the insulating film 2. It is formed so that it becomes. That is, when the thickness of the conductive film 5a formed on the flat portion of the insulating film 2 is 0.2 μm, the thickness of the conductive film 5b formed on the side wall of the opening 4 is 0.01 μm to 0.2 μm. It is formed using a directional sputtering method or the like to have a thickness of 02 μm. Therefore, in such a semiconductor device, scratches and depressions can be prevented from being formed on the surface of the insulating film 2, and the semiconductor device can be formed on the side wall of the opening 4 without performing a complicated manufacturing process. Due to the influence of the conductive film 5b, the Cu film wiring 6
Unnecessarily decreasing the width of 1 can be suppressed.

In the above-described semiconductor device, the thickness of the conductive film 5b on the side wall of the opening 4 is 5% to 10% of the thickness of the conductive film 5a on the flat portion. It goes without saying that the semiconductor device described above can be manufactured even if the ratio is other than the above. In the above-described semiconductor device, the case where the wiring has one layer has been described. However, the present invention can be applied to a semiconductor device having a multilayer wiring structure of two or more layers. Furthermore, although a silicon oxide film is used as a material of the first insulating film and the second insulating film, an organic material such as a polyimide film or an organic SOG, on which a scratch is easily formed by polishing, may be used. The invention is particularly effective. Further, the materials of the first insulating film and the second insulating film may be different. Further, a structure without the second insulating film may be employed.

Embodiment 2 In the semiconductor device according to the first embodiment, as shown in FIG. 1, the first insulating film 2 and the Cu film wiring 61 are configured to be covered with the second insulating film 7 made of a silicon oxide film. However, as shown in FIG. 10, the protruding upper end of the Cu film wiring 61 is covered with a third insulating film 8 made of a silicon nitride film, and a second insulating film 7 made of a silicon oxide film is further formed thereon. It is good also as a structure which covers.

The semiconductor device having such a structure is formed by the first etching by the dry etching shown in FIG.
After the step of selectively removing the first conductive film 5 a on the insulating film 2 is completed, a silicon nitride film is formed to a thickness of about 0.05 μm by thermal CVD or plasma CVD to form a Cu film wiring 6.
The second insulating film 7 is obtained by covering the region including the upper end portion of the first insulating film 1 and then forming a 0.8 μm thick silicon oxide film as the second insulating film 7 on the third insulating film 8.

The Cu film generally has a property of being easily oxidized. Therefore, when the Cu film wiring comes into direct contact with the oxide film or the like, there arises a problem that its surface is oxidized. However, in the semiconductor device shown in the second embodiment, the upper end of the Cu film wiring 61 is covered with the third insulating film 8 made of a silicon nitride film, so that the Cu film wiring directly contacts the oxide film or the like. Therefore, there is a feature that a Cu film wiring having excellent oxidation resistance can be formed. Although the second insulating film is formed over the third insulating film in the semiconductor device according to the second embodiment, a structure without the second insulating film may be employed. Further, the third insulating film is not limited to the silicon nitride film, and may be another insulating film containing no oxygen.

Embodiment 3 FIG. 11 is a sectional view of a semiconductor device according to a third embodiment of the present invention. In FIG. 11, reference numeral 81 denotes silicon formed between the side wall of the opening 4 of the first insulating film 2 and the Cu film wiring 61 to cover the side surface and the upper surface of the Cu film wiring 61. This is a third insulating film made of a nitride film. Note that other portions are the same as those of the semiconductor device described in Embodiment 1.

Next, a method of manufacturing the semiconductor device shown in FIG. 11 will be described. First, in Embodiment 1, FIGS.
Steps similar to those described with reference to FIG. 9 are performed. Next, as shown in FIG. 12, the first conductive film 5b on the side wall of the opening 4 is selectively removed by dry etching.
A gap 9 is formed between the side wall of the opening 4 and the Cu film wiring 61. This dry etching is performed using, for example, a gas containing chlorine as an etching gas when the material of the conductive film 5 is TiN. Next, as shown in FIG. 13, a third insulating film 81 made of a silicon nitride film is formed by thermal CVD or plasma CVD so as to fill the void 9, and a side surface portion and an upper portion of the Cu film wiring 61 are formed. And cover. Then, a 0.8 μm-thick silicon oxide film as the second insulating film 7 is formed on the third insulating film 81 by the same method, whereby the semiconductor device as shown in FIG. 11 is obtained. Can be

In the semiconductor device described in the third embodiment, since the upper surface and the side surface of the Cu film wiring 61 are covered with the third insulating film made of the silicon nitride film, the oxidation resistance is improved. There is a feature that an excellent Cu film wiring can be formed. Although the second insulating film is formed over the third insulating film in the semiconductor device according to the third embodiment, a structure without the second insulating film may be employed. Also, the third
Is not limited to the silicon nitride film, but may be another insulating film containing no oxygen.

Embodiment 4 FIG. In the semiconductor device according to the third embodiment, the upper surface and the side surface of the Cu film wiring 61 are configured to be covered with the insulating film such as the silicon nitride film 81. However, the semiconductor device according to the fourth embodiment has the Cu film The upper and side surfaces of the wiring 61 are covered with an Al film.
FIG. 14 is a sectional view showing a structure of a semiconductor device according to a fourth embodiment of the present invention. In FIG. 14, reference numeral 10 is formed between the side wall of the opening 4 of the first insulating film 2 and the Cu film wiring 61 so as to cover the side surface and the upper surface of the Cu film wiring 61. This is an Al film. Note that other portions are similar to those of the semiconductor device described in Embodiment 1.

Next, a method of manufacturing the semiconductor device configured as shown in FIG. 14 will be described. First, in the same step as that shown in FIG.
A gap 9 is formed between the side wall of the opening 4 of the insulating film 2 and the Cu film wiring 61. Next, as shown in FIG.
An Al film, which is the second conductive film 10, is selectively grown only on the surface of the Cu film wiring 61 by the VD method, and the side surface and the upper surface of the Cu film wiring 61 are covered with the Al film 10 so as to fill the void 9. The selective growth of the Al film 10 is performed, for example, by using dimethyl aluminum hydride as a source gas and forming the film at a temperature of 200 ° C. and a pressure of 1 to 5 torr, thereby forming the first insulating film 2 as a silicon oxide film. The Al film can be selectively formed only on the surface of the Cu film wiring 61 without being formed on the upper surface.

Next, the second layer is formed by a plasma CVD method or the like.
0.8 μm thick silicon oxide film, which is the insulating film 7 of FIG.
Cu film wiring 61 and first insulating film 2 covered with l film 10
Thus, a semiconductor device as shown in FIG. 14 is obtained. In the semiconductor device described in the fourth embodiment, not only the bottom surface of the Cu film wiring 61 is covered with the conductive film 5 but also the side surface and the top surface are covered with the Al film. The feature is that a Cu film wiring having excellent oxidation resistance can be formed. Further, since the Al film has a low electric resistance, the wiring resistance is reduced as compared with the case where the side surface and the upper surface of the Cu film wiring 61 are covered with the third insulating film as described in the third embodiment. This makes it possible to increase the speed of the semiconductor device.

In the fourth embodiment, the case where the Al film is employed has been described.
Other conductive materials that can prevent oxidation of the film wiring and have low resistance may be used. In the fourth embodiment, the second insulating film 7 is formed on the Cu film wiring 61 and the first insulating film 2 covered with the Al film 10. It may be a structure that is not formed.

Embodiment 5 FIG. In the first embodiment,
As described with reference to FIG. 5, when forming the conductive film 5 on the insulating film 2, the conductive film 5 is formed on a flat portion of the insulating film 2 by one film forming process using a directional film forming method. The film thickness formed on the side wall of the opening 4 is smaller than the film thickness formed. In such a film forming method, the number of steps is reduced, but the conductive film 5 formed on the side wall of the opening 4 is formed.
b and a conductive film 5a formed on a flat portion of the first insulating film 2
The film thickness ratio was affected by the film forming conditions, and could not be controlled independently. The fifth embodiment provides a method of manufacturing a semiconductor device in which such control of the film thickness ratio can be performed independently. Hereinafter, a method of manufacturing the semiconductor device according to the fifth embodiment will be described with reference to FIGS.

First, as shown in FIG. 16, the surface of a semiconductor substrate 1 made of a silicon
After the first insulating film 2 is formed by depositing a silicon oxide film to a thickness of about 1 μm by a VD method or the like, the TiN film as the first conductive film 11 is further formed to a thickness of 0.2 μm by a CVD method or a sputtering method. It is formed to a thickness of about 0.3 μm. Next, as shown in FIG. 17, a resist film is formed on the surface of the first conductive film 11, and is patterned by photolithography to form a resist pattern 3, which is shown in FIGS. 18 and 19. As described above, the first conductive film 11 and the first insulating film 2 are etched by anisotropic dry etching, and the opening 4 penetrates the first conductive film 11 so that the opening 4 is formed in the first insulating film 2. Form.

Next, as shown in FIG. 20, after removing the resist pattern 3, as shown in FIG. 21, the TiN film, which is the second conductive film 50, is removed by CVD or sputtering.
A thickness of about 05 μm is formed on the inner wall of the opening 4 and on the surface of the first conductive film 11, and as shown in FIG. The first conductive film 50 is formed to be buried and to have a thickness of about 0.4 μm on the surface of the first conductive film 50. It is to be noted that the Cu film 6 formed here is not limited to pure Cu, as described in the first embodiment.

Next, as shown in FIG. 23, the Cu film 6 is polished by a chemical mechanical polishing method until the Cu film on the first conductive film 11 is completely removed.
The film wiring 61 is formed. Here, in this polishing, the Cu film is polished so that at least the first conductive film remains. That is, this polishing removes part or all of the second conductive film 50 in the flat portion of the insulating film 2, but at least the first conductive film 11 thereunder is not completely removed. This is performed so as to remain on the first insulating film 2. Therefore,
The Cu film wiring 61 formed in this step is not for the first insulating film 2 but for the remaining first conductive film 1
It is formed so as to be flat with respect to the surface of the first or second conductive film 50.

Next, as shown in FIG. 24, the remaining first conductive film 11 and the second conductive film 50 on the surface of the first conductive film 11 are selectively removed by dry etching. . Here, for example, when the material of the first conductive film 11 and the material of the second conductive film 5 are both TiN, a gas containing chlorine is used as an etching gas at several degrees Celsius. Etching is performed at a relatively low temperature of about several tens of degrees Celsius. By such an etching process, C
The u film 61 is formed so as to protrude from the flat portion of the first insulating film 2.

Next, as shown in FIG. 25, a 0.8 μm-thick silicon oxide film as the second insulating film 7 is formed on the first insulating film 2 and the Cu film by a thermal CVD method or a plasma CVD method. The wiring 61 is formed so as to cover the surface.

The semiconductor device obtained by the manufacturing method of the fifth embodiment has the same configuration as the semiconductor device shown in the first embodiment. However, in the manufacturing method described in the fifth embodiment, the first conductive film 11 is formed only on the flat portion of the first insulating film 2, so that the first conductive film 11 is formed on the flat portion of the first insulating film 2. It is possible to independently control the thickness of the conductive film and the thickness of the conductive film formed on the side wall of the opening 4. As a result, the degree of freedom in setting other process conditions such as a polishing step is increased, and the Cu film wiring 61 is formed on the first insulating film 2.
Since the height of the protruding portion can be controlled, the semiconductor device described in Embodiment 1 can be manufactured with better control.

It goes without saying that the method of manufacturing a semiconductor device described in the fifth embodiment can be applied to the manufacture of the semiconductor device described in the second to fourth embodiments. In addition, the first conductive film 11 and the second
The material of the conductive film 50 is not limited to the TiN film as long as the material has an etching characteristic different from that of the Cu film wiring 61, and may be another material, for example, a film made of a compound of Ti, silicon and nitrogen, or easily etched with chlorine. Such an aluminum alloy film may be used. Further, the present invention may be applied to a semiconductor device having a multilayer wiring structure of two or more layers, as well as a case where the wiring has one layer. Furthermore, the second in FIG.
The formation of the conductive film 50 may be omitted, and the Cu film 6 may be formed directly inside the opening 4 of the insulating film 2.

[0052]

The semiconductor device according to the present invention has a structure in which the Cu film wiring protrudes from the first insulating film formed on the semiconductor substrate.
There is no need to perform polishing until the film becomes flat with respect to the first insulating film 2, and the surface of the first insulating film is not directly polished. As a result, scratches are not formed on the surface of the first insulating film, and there is an effect that the problem that the wiring is short-circuited by Cu or TiN remaining in the scratches can be avoided. Further, since no depression is formed on the surface of the first insulating film, there is an effect that the problem that the resistance of the Cu film wiring increases due to the formation of the depression can be avoided.

Further, in the semiconductor device according to the present invention, of the conductive film covering the inner wall of the opening of the insulating film, the thickness of the conductive film on the side wall of the opening is smaller than that of the bottom of the opening. Since the film is formed to be thinner than the film thickness, there is an effect that the width of the Cu film wiring can be prevented from being unnecessarily reduced without performing a complicated manufacturing process.

In the semiconductor device according to the present invention, since the upper end of the Cu film wiring projecting from the surface of the insulating film is covered with the silicon nitride film, the Cu film having excellent oxidation resistance is formed.
There is an effect that a film wiring can be formed.

Further, the semiconductor device according to the present invention has a C
Since the side and top surfaces of the u film wiring are covered with the silicon nitride film, there is an effect that a Cu film wiring having excellent oxidation resistance can be formed.

Further, according to the semiconductor device of the present invention,
Since the side surface and the top surface of the film wiring are covered with the Al film, there is an effect that a Cu film wiring having excellent oxidation resistance and low wiring resistance can be formed.

Further, according to the method of manufacturing a semiconductor device of the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and an insulating film including an inner wall portion of the opening Forming a conductive film on the conductive film, forming a Cu film on the conductive film, and polishing the Cu film so that the conductive film on the flat portion of the insulating film remains. Removing the conductive film remaining on the flat portion of the insulating film, so that the surface of the insulating film is not directly polished, and scratches and dents are formed on the surface of the insulating film. And a reliable semiconductor device can be manufactured.

Further, in the method of manufacturing a semiconductor device according to the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and an insulating film including an inner wall of the opening A conductive film is formed on the insulating film so that the thickness of the conductive film formed on the side wall of the opening of the insulating film is smaller than the thickness of the conductive film formed on the flat portion of the insulating film. Forming a Cu film on the conductive film; polishing the Cu film so that the conductive film remains on a flat portion of the insulating film; The step of removing the conductive film remaining on the flat portion is included, so that the surface of the insulating film is not directly polished, thereby preventing the formation of scratches and dents on the surface of the insulating film It is possible to prevent the width of the Cu film wiring from being unnecessarily reduced. There is an effect that the manufacturing of the semiconductor device becomes possible.

Further, in the method of manufacturing a semiconductor device according to the present invention, a step of forming an insulating film on a semiconductor substrate, a step of forming a first conductive film on the insulating film, and a step of forming the first conductive film Forming an opening in the insulating film through the conductive film; and forming a second conductive film on the inner wall of the opening and the first conductive film.
Forming a Cu film on the second conductive film so as to fill the opening, and forming a first conductive film on at least a flat portion of the insulating film. Polishing the Cu film so that the conductive film remains, a first conductive film remaining on the flat portion of the insulating film, and a second conductive film on the surface of the first conductive film. And independently controlling the thickness of the conductive film formed on the flat portion of the first insulating film and the thickness of the conductive film formed on the side wall portion of the opening. Becomes possible. As a result, it is possible to prevent the formation of scratches and dents on the surface of the first insulating film and to controllably manufacture a semiconductor device capable of suppressing an unnecessary reduction in the width of the Cu film wiring. There is.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductor device according to a first embodiment of the present invention;

FIG. 2 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 3 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 4 is a sectional view illustrating the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 5 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 6 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 7 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 8 is a sectional view showing the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 9 is a sectional view illustrating the method for manufacturing the semiconductor device of the first embodiment of the present invention.

FIG. 10 is a sectional view showing a semiconductor device according to a second embodiment of the present invention;

FIG. 11 is a sectional view showing a semiconductor device according to a third embodiment of the present invention;

FIG. 12 is a sectional view illustrating the method of manufacturing the semiconductor device of the third embodiment of the present invention.

FIG. 13 is a sectional view showing the method of manufacturing the semiconductor device according to the third embodiment of the present invention.

FIG. 14 is a sectional view showing a semiconductor device according to a fourth embodiment of the present invention;

FIG. 15 is a sectional view showing the method for manufacturing the semiconductor device of the fourth embodiment of the present invention.

FIG. 16 is a sectional view showing the method of manufacturing the semiconductor device according to the fifth embodiment of the present invention.

FIG. 17 is a sectional view illustrating the method of manufacturing the semiconductor device of the fifth embodiment of the present invention.

FIG. 18 is a sectional view illustrating the method of manufacturing the semiconductor device according to the fifth embodiment of the present invention.

FIG. 19 is a sectional view showing the method of manufacturing the semiconductor device according to the fifth embodiment of the present invention.

FIG. 20 is a sectional view showing the method of manufacturing the semiconductor device according to the fifth embodiment of the present invention;

FIG. 21 is a sectional view showing the method of manufacturing the semiconductor device of the fifth embodiment of the present invention.

FIG. 22 is a sectional view showing the method of manufacturing the semiconductor device according to the fifth embodiment of the present invention.

FIG. 23 is a sectional view showing the method of manufacturing the semiconductor device of the fifth embodiment of the present invention.

FIG. 24 is a sectional view illustrating the method of manufacturing the semiconductor device of the fifth embodiment of the present invention.

FIG. 25 is a sectional view illustrating the method of manufacturing the semiconductor device of the fifth embodiment of the present invention.

FIG. 26 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 27 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 28 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 29 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 30 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 31 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 32 is a cross-sectional view showing a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

Reference Signs List 1 semiconductor substrate 2 first insulating film 3 resist pattern 4 opening formed in first insulating film 5 conductive film 5a conductive film in flat portion of insulating film 5b conductive film in side wall of opening 6 Cu film 61 Cu film wiring 7 Second insulating film 8 Third insulating film 81 Third insulating film 9 Void 10 Al film 11 First conductive film 50 Second conductive film

Claims (11)

[Claims] 1. A semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, and a Cu film embedded in the opening of the insulating film and having an upper end projecting from the surface of the insulating film. A semiconductor device comprising: a wiring; 2. A semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, a conductive film covering an inner wall of the opening, and embedded in the opening, and an upper end is embedded in the opening. A semiconductor device comprising: a Cu film wiring projecting from a surface of an insulating film. 3. The conductive film on the side wall of the opening is thinner than the conductive film on the bottom of the opening.
13. The semiconductor device according to claim 1. 4. The semiconductor device according to claim 1, wherein an upper end portion of the Cu film wiring projecting from a surface of the insulating film formed on the semiconductor substrate is covered with a silicon oxide film. 4. The semiconductor device according to 3. 5. The semiconductor device according to claim 1, wherein an upper end of the Cu film wiring projecting from a surface of the insulating film formed on the semiconductor substrate is covered with a silicon nitride film. 4. The semiconductor device according to 3. 6. A semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, a conductive film covering a bottom surface of the opening, and embedded in the opening, and an upper end is embedded in the opening. A semiconductor device comprising: a Cu film wiring projecting from a surface of an insulating film and having a top surface and side surfaces covered with a silicon nitride film. 7. A semiconductor substrate, an insulating film formed on the semiconductor substrate and having an opening, a conductive film covering a bottom surface of the opening, and embedded in the opening, and an upper end is embedded in the opening. A semiconductor device, comprising: a Cu film wiring projecting from a surface of an insulating film and having a top surface and side surfaces covered with an Al film. 8. The conductive film covering the opening of the insulating film is any one of a titanium nitride film, a titanium silicon nitride film, and an aluminum alloy film. The semiconductor device according to claim 7. 9. A step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and a step of forming a conductive film on the insulating film including an inner wall of the opening. Forming a Cu film on the conductive film; and forming the Cu film such that the conductive film on the flat portion of the insulating film remains.
A method of manufacturing a semiconductor device, comprising: a step of polishing a film; and a step of removing a conductive film remaining on a flat portion of the insulating film. 10. A step of forming an insulating film on a semiconductor substrate, a step of forming an opening in the insulating film, and forming a conductive film on the insulating film including an inner wall portion of the opening. Forming a thickness of a conductive film formed on a side wall portion of the opening portion so as to be smaller than a thickness of a conductive film formed on a flat portion of the insulating film; Forming a Cu film thereon, polishing the Cu film so that the conductive film on the flat portion of the insulating film remains, and forming a conductive film remaining on the flat portion of the insulating film. Removing the semiconductor device. 11. A step of forming an insulating film on a semiconductor substrate, a step of forming a first conductive film on the insulating film,
Forming an opening in the insulating film through the first conductive film; and forming a second conductive film on an inner wall portion of the opening of the insulating film and a surface of the first conductive film. Forming, and forming a Cu film on the second conductive film,
Polishing the Cu film so that at least the first conductive film on the flat portion of the insulating film remains; and forming the first conductive film remaining on the flat portion of the insulating film and the first conductive film. 1
Removing the second conductive film on the surface of the conductive film.