KR20050020801A - Electronic device and its manufacturing method - Google Patents

Abstract

A first nitrogen-containing insulating film 103 is formed below the low dielectric constant film 105 having the via hole 108 via the first nitrogen-free insulating film 104. A second nitrogen-containing insulating film 107 is formed over the low dielectric constant film 105 with the second nitrogen-free insulating film 106 interposed therebetween.

Description

ELECTRONIC DEVICE AND ITS MANUFACTURING METHOD

TECHNICAL FIELD The present invention relates to an electronic device and a method for manufacturing the same, and more particularly, to a wiring forming technology.

In recent years, as the integration density of integrated circuits increases, wiring intervals become narrower, and electric parasitic capacitance generated between wirings increases. On the other hand, in integrated circuits requiring high speed operation, it is necessary to reduce the electric parasitic capacitance between wirings.

Therefore, in order to reduce the electrical parasitic capacitance between wirings, a method of reducing the dielectric constant of the insulating film between wirings has been studied. As the method of reducing the inter-wiring electric parasitic capacity, for example, a film made of a material having a lower dielectric constant than a silicon oxide film (i.e. a low dielectric constant film), for example, a carbon-containing silicon oxide film or porous A method using a film or the like has been proposed. The carbon-containing silicon oxide film contains carbon in the film in the form of an alkyl group or a phenyl group having a large volume. As a result, the density (about 1.0 to 1.3 g / cm 3) of the carbon-containing silicon oxide film is smaller than the density (about 2.3 g / cm 3) of the silicon oxide film, and the dielectric constant (about 2.0 to 3.0) of the carbon-containing silicon oxide film is also reduced to silicon. It becomes small compared with the dielectric constant (about 3.9-4.3) of an oxide film.

By the way, since the film density of low dielectric constant films, such as a carbon containing silicon oxide film, is low compared with the conventional interwire insulation film, such as a silicon oxide film, for example, a low dielectric constant film is easy to absorb nitrogen which exists in air | atmosphere in a film | membrane when it is exposed to air | atmosphere. . As a result, for example, when performing the photolithography process for forming the groove pattern for upper metal wiring on the carbon containing silicon oxide film in which the via hole was formed, the following problem arises. That is, as a result of insufficient development of the photoresist applied in the vicinity of the via hole, unnecessary photoresist remains, so that a desired groove pattern cannot be formed. This problem occurs for the following reasons. That is, the amine present in the carbon-containing silicon oxide film having the via hole or the basic material derived from nitrogen in the silicon nitride carbide film formed under the carbon-containing silicon oxide film is a photoresist (chemically amplified resist) on the carbon-containing silicon oxide film through the via hole. Is spreading to the middle. As a result, since the base concentration in the resist rises, the acid generated in the acid generating material in the resist is neutralized at the time of exposure to form the groove pattern, so that continuous acid generation reaction in the acrylic resist or the like does not proceed, for example, poor development. This happens. This phenomenon is called resist poisoning. When resist poisoning occurs, for example, a situation where the lower metal wiring and the upper metal wiring are not normally connected, that is, a wiring failure occurs.

On the other hand, the non-patent document 1 (Proceedings of the 2002 International Interconnect Technology Conference, M. Fayolle et al., P39-41) discloses the wiring structure which prevents resist poisoning, and its manufacturing method.

7 is a cross-sectional view showing a conventional electronic device wiring structure disclosed in Non-Patent Document 1. FIG.

As shown in FIG. 7, the lower metal wiring 2 comprised of the metal barrier film 2a and the copper film 2b in the 1st insulating film 1 which consists of a silicon oxide film formed on the silicon substrate (not shown). Is formed. On the lower metal wiring 2 and on the first insulating film 1, a second insulating film 3 made of a silicon carbide film is formed. On the second insulating film 3, a third insulating film 4 made of a carbon-containing silicon oxide film is formed. On the third insulating film 4, a fourth insulating film 5 made of a silicon carbide film is formed. On the fourth insulating film 5, a fifth insulating film 6 made of a carbon-containing silicon oxide film is formed. In the second insulating film 3 and the third insulating film 4, a via hole 7 extending to the lower metal wiring 2 is formed, and in the fourth insulating film 5 and the fifth insulating film 6, a via hole 7 is formed. Wiring grooves (8) are formed. In the via hole 7 and the wiring groove 8, the metal barrier film 9 and the copper film 10 are sequentially formed, whereby the via plug 11 and the upper metal wiring 12 are formed. The via plug 11 connects the lower metal wiring 2 and the upper metal wiring 12.

(A)-(f) is sectional drawing which shows each process of the conventional electronic device manufacturing method disclosed by the nonpatent literature 1, ie, the method for manufacturing the electronic device shown in FIG.

First, as shown in FIG. 8A, after forming the first insulating film 1 on the silicon substrate (not shown), the metal barrier film 2a and the copper film 2b are formed on the first insulating film 1. The lower metal wiring 2 which consists of these is purchased.

Next, as shown in Fig. 8B, on the first insulating film 1 and the lower metal wiring 2, the second insulating film 3 made of silicon carbide film and the third made of carbon-containing silicon oxide film The insulating film 4, the fourth insulating film 5 made of a silicon carbide film, the fifth insulating film 6 made of a carbon-containing silicon oxide film, and the sixth insulating film 13 made of a silicon carbide film are sequentially deposited.

Next, a photoresist is applied on the sixth insulating film 13, and photolithography is performed on the coated photoresist to form a resist film (not shown) having a hole pattern. Thereafter, dry etching is performed on the sixth insulating film 13 and the fifth insulating film 6 with this resist film as a mask, and then photoresist is removed by ashing. As a result, as shown in FIG. 8C, holes 14 corresponding to the via holes 7 (see FIG. 8E) are formed in the sixth insulating film 13 and the fifth insulating film 6. .

Next, by applying a photoresist on the sixth insulating film 13 and performing photolithography on the coated photoresist, the resist film 15 having a desired groove pattern, specifically, the wiring groove 8 ( A resist film 15 having an opening 15a corresponding to Fig. 8E) is formed.

Next, the sixth insulating film 13, the fifth insulating film 6, the resist film 15 having the groove pattern and the sixth insulating film 13 and the fifth insulating film 6 having the hole pattern are respectively masked. Dry etching is sequentially performed on the fourth insulating film 5 and the third insulating film 4. As a result, as shown in FIG. 8E, the via hole 7 is formed in the third insulating film 4, and the wiring groove 8 is formed in the fourth insulating film 5 and the fifth insulating film 6. However, after the above-mentioned dry etching, the resist film 15 is removed and washed, and then the second insulating film 3 (regions for forming the hole holes 7) and the fourth insulating film 5 (wiring) each made of a silicon carbide film, respectively. The groove 8 forming region) and the sixth insulating film 13 are simultaneously removed by the front etch back. As a result, as shown in FIG. 8E, desired via holes 7 and wiring grooves 8 are formed.

Next, the metal barrier film 9 and the copper film 10 are sequentially deposited on the fifth insulating film 6 so as to completely fill the via hole 7 and the wiring groove 8, and then, outside the wiring groove 8. The metal barrier film 9 and the copper film 10 are removed by chemical mechanical polishing (CMP). As a result, as shown in FIG. 8F, the via plug 11 is formed in the via hole 7, and the upper metal wiring 12 is formed in the wiring groove 8.

In Non-Patent Document 1, as the second insulating film 3, the fourth insulating film 5, and the sixth insulating film 13, a silicon carbide film containing no nitrogen is used to diffuse the amine or the like via the hole 14. It has been reported that resist poisoning caused by

However, in the conventional wiring structure described above, a nitrogen-free silicon carbide film having a poorer film quality than the silicon nitride carbide film is used instead of the silicon nitride carbide film for the resist poisoning countermeasure, so that there is a problem that the leakage current increases. Moreover, since the film stability of a silicon carbide film is bad, there also exists a problem that the film quality will change with time when this film is left to stand after depositing.

1 is a cross-sectional view showing a wiring structure of an electronic device according to a first embodiment of the present invention.

Fig.2 (a)-(f) is sectional drawing which shows each process of the electronic device manufacturing method which concerns on 1st Embodiment of this invention.

3 is a cross-sectional view showing a wiring structure of an electronic device according to a comparative example.

4 (a) to 4 (f) are cross-sectional views showing respective steps of the electronic device manufacturing method according to the comparative example.

5 is a cross-sectional view showing a wiring structure of an electronic device according to a second embodiment of the present invention.

6 (a) to 6 (f) are cross-sectional views showing respective steps of the electronic device manufacturing method according to the second embodiment of the present invention.

7 is a cross-sectional view showing a conventional electronic device wiring structure.

8 (a) to 8 (f) are cross-sectional views showing respective steps of a conventional electronic device manufacturing method.

In view of the above, it is an object of the present invention to prevent resist poisoning while suppressing an increase in leakage current and change in film quality over time in an inter-wire insulating film.

In order to achieve the above object, the first electronic device according to the present invention includes a low dielectric constant film having holes, a nitrogen-free insulating film formed below the low-k dielectric film, and a nitrogen-containing insulating film formed below the nitrogen-free insulating film. .

According to the first electronic device, a nitrogen-free insulating film is formed between the low dielectric constant film serving as the inter-wire insulating film and the nitrogen-containing insulating film below it. That is, since the low dielectric constant film and the nitrogen-containing insulating film do not directly contact each other, the introduction of nitrogen into the low dielectric constant film can be suppressed. As a result, when a chemically amplified resist is applied onto the low dielectric constant film on which holes are formed, amines and the like can be diffused from the low dielectric constant film into the resist via the holes, that is, resist poisoning can be prevented. Further, since a nitrogen-containing insulating film (for example, silicon nitride carbide film) having a good film quality is formed below the low dielectric film, it is possible to prevent an increase in leakage current or a change in film quality over time.

In addition, according to the first electronic device, since the nitrogen-free insulating film is deposited by, for example, plasma CVD (chemical vapor deposition) method, the film quality of the nitrogen-containing insulating film below it can be stabilized, so that nitrogen contained in the nitrogen-containing insulating film It becomes hard to be free. As a result, the introduction of nitrogen into the low dielectric constant film can be suppressed more reliably.

Here, in this specification, an nitrogen-free insulating film means the insulating film whose nitrogen contained in a film is less than 1 * 10 <^19> atoms / cm <^3> .

In the first electronic device, the hole penetrates each of the nitrogen-free insulating film and the nitrogen-containing insulating film, and further includes a lower layer wiring connected to the hole below the hole, and the upper surface of the lower layer wiring except the hole connection region has a nitrogen-containing insulating film. It is preferable to coat with.

In this case, by using an insulating film containing no oxygen as the insulating film containing nitrogen, the oxidation of the lower layer wiring can be prevented.

In the first electronic device, the lower surface of the low dielectric constant film and the upper surface of the nitrogen-free insulating film are preferably in contact with each other.

This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

The second electronic device according to the present invention includes a low dielectric constant film having holes, a nitrogen-free insulating film formed above the low-k dielectric film, and a nitrogen-containing insulating film formed above the nitrogen-free insulating film.

According to the second electronic device, a nitrogen-free insulating film is formed between the low dielectric constant film as the inter-wire insulating film and the nitrogen-containing insulating film thereon. In other words, the low dielectric constant film and the nitrogen-containing insulating film do not directly contact each other. Therefore, the introduction of nitrogen into the low dielectric constant film can be suppressed. Therefore, when a chemically amplified resist is applied over the low dielectric constant film on which the hole is formed, amines or the like diffuse through the hole into the resist, that is, the resist. Poisoning can be prevented. In addition, since a nitrogen-containing insulating film (for example, silicon nitride carbide film) having a good film quality is formed above the low dielectric film, it is possible to prevent an increase in leakage current or a change in film quality over time.

In addition, according to the second electronic device, since the nitrogen-containing insulating film is formed on the low dielectric film via the nitrogen-free insulating film, the low-k film is exposed directly to the atmosphere containing nitrogen (plasma, etc.) after the low-k film is formed. none. This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

In the second electronic device, it is preferable that the nitrogen-containing insulating film is an antireflection film, and a concave portion connecting to the hole is formed at least on an upper portion of the nitrogen-containing insulating film, the nitrogen-free insulating film, and the low dielectric constant film.

In this way, in the lithography process for forming the holes or the concave portions, there is no need to separately form an antireflection film made of an organic material, for example, so that the number of steps can be reduced.

In the second electronic device, the upper surface of the low dielectric constant film and the lower surface of the nitrogen-free insulating film are preferably in contact with each other.

This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

The third electronic device according to the present invention includes a low dielectric constant film having holes, a first nitrogen-free insulating film formed below the low dielectric constant film, and a second nitrogen-free insulating film formed above the low dielectric constant film, The recessed part which penetrates a 1st nitrogen-free insulating film, and is connected with a hole is formed in at least upper part of a 2nd nitrogen-free insulating film and a low dielectric constant film.

According to the third electronic device, since the nitrogen-free insulating films are formed above and below the low dielectric constant film, which is the inter-wire insulating film, the introduction of nitrogen into the low dielectric constant film can be more surely suppressed. As a result, when a hole is formed in the low dielectric constant film and a chemically amplified resist is applied over the low dielectric constant film in the lithography process for forming the concave portion connected to the hole, an amine or the like is formed in the low dielectric constant film through the hole. It is possible to prevent the diffusion into the medium, that is, resist poisoning.

In the third electronic device, the lower dielectric constant film is preferably in contact with the upper surface of the first nitrogen-free insulating film.

This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

In the third electronic device, the upper surface of the low dielectric constant film and the lower surface of the second nitrogen-free insulating film are preferably in contact with each other.

This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

A fourth electronic device according to the present invention includes a low dielectric constant film having holes and a low density insulating film having a film density of 1.3 g / cm 3 or less formed above the low dielectric constant film.

According to the fourth electronic device, since the low density insulating film is formed above the low dielectric constant film as the inter-wire insulating film, nitrogen introduced into the low dielectric constant film or nitrogen present in the low density insulating film itself is easily discharged to the outside through the low density insulating film. As a result, since amines and the like do not concentrate in the holes formed in the low dielectric constant film, when the chemically amplified resist is applied over the low dielectric constant film, the amount of amine or the like per unit volume in the resist near the hole becomes very small. As a result, resist poisoning can be prevented. In the fourth electronic device, the density of the low density insulating film is preferably 0.4 g / cm 3 or more in consideration of the stability of the film.

In the fourth electronic device, the low density insulating film preferably contains nitrogen.

In this way, since the film quality of the low density insulating film is improved, it is possible to prevent an increase in the leakage current or a change in the film quality over time.

In the fourth electronic device, it is preferable to further include a nitrogen-containing insulating film formed under the low dielectric constant film.

In this case, since the film quality of the nitrogen-containing insulating film is good, it is possible to prevent an increase in the leakage current or a change in the film quality over time.

In the first, second, third or fourth electronic device, the low dielectric constant film is preferably a carbon-containing silicon oxide film or a porous film.

In this way, the capacitance between wirings can be reliably reduced. As the carbon-containing silicon oxide film, an SiOC film may be used.

A method for manufacturing a first electronic device according to the present invention includes a step of sequentially forming a nitrogen-free insulating film and a low dielectric constant film on a nitrogen-containing insulating film, a step of forming holes in the low dielectric constant film, and a low dielectric constant film on which the holes are formed. Applying a chemically amplified resist and exposing and developing the applied chemically amplified resist to form a resist film having an opening in a predetermined region including a region in which a hole is formed; And etching the dielectric constant film to form a recess for connecting with the hole.

According to the first electronic device manufacturing method, holes are formed in the low dielectric constant film formed on the nitrogen-containing insulating film via the nitrogen-free insulating film, and then a chemically amplified resist is applied on the low dielectric constant film. In other words, since the nitrogen-free insulating film is formed between the low dielectric constant film and the nitrogen-containing insulating film, the low dielectric constant film and the nitrogen-containing insulating film do not directly contact each other. As a result, the introduction of nitrogen into the low dielectric constant film can be suppressed. Therefore, when a chemically amplified resist is applied onto the low dielectric constant film having holes formed therein, amines or the like are diffused into the resist through the holes, that is, resist poisoning is prevented. can do. Further, since a nitrogen-containing insulating film (for example, silicon nitride carbide film) having a good film quality is formed below the low dielectric film, it is possible to prevent an increase in leakage current or a change in film quality over time.

In addition, according to the first electronic device manufacturing method, since the nitrogen-free insulating film is deposited by, for example, plasma CVD, the film quality of the nitrogen-containing insulating film beneath it can be stabilized, so that nitrogen contained in the nitrogen-containing insulating film is difficult to be released. Lose. As a result, it is possible to more reliably suppress the introduction of nitrogen into the low dielectric constant film.

In the first electronic device manufacturing method, the nitrogen-containing insulating film is preferably formed so as to cover the lower layer wiring.

In this case, oxidation of the lower layer wiring can be prevented by using an insulating film containing no oxygen as the nitrogen-containing insulating film.

In the first electronic device manufacturing method, the step of forming a hole includes a step of forming a hole in the low dielectric constant film and the nitrogen-free insulating film, and after the step of forming the recess, the nitrogen-containing insulating film below the hole is removed. It is preferable to further provide the process of making.

By doing in this way, etching damage and ashing damage (for example, surface oxidation of wiring, an element, etc.) generate | occur | produce in the wiring and the element formed in the lower part of a hole can be prevented.

A second electronic device manufacturing method according to the present invention comprises the steps of sequentially forming a nitrogen-free insulating film and a nitrogen-containing insulating film on a low dielectric constant film, and forming a hole in the low dielectric constant film formed with a nitrogen-free insulating film and a nitrogen-containing insulating film By applying a chemically amplified resist over the low dielectric constant film on which the hole is formed, and exposing and developing the coated chemically amplified resist to form a resist film having an opening in a predetermined region including the region where the hole is formed. And forming a concave portion which is connected to the hole by etching the low dielectric constant film using the resist film as a mask.

According to the second electronic device manufacturing method, after the nitrogen-free insulating film and the nitrogen-containing insulating film are sequentially formed on the low dielectric constant film, holes are formed in the low dielectric constant film, and then a chemically amplified resist is applied on the low dielectric constant film. do. That is, since the nitrogen-free insulating film is formed between the low dielectric constant film and the nitrogen-containing insulating film, the low dielectric constant film and the nitrogen-containing insulating film do not directly contact each other. As a result, the introduction of nitrogen into the low dielectric constant film can be suppressed. Therefore, when a chemically amplified resist is applied onto the low dielectric constant film having holes formed therein, amines or the like are diffused into the resist through the holes, that is, resist poisoning is prevented. can do. In addition, since a nitrogen-containing insulating film (for example, silicon nitride carbide film) having a good film quality is formed above the low dielectric film, it is possible to prevent an increase in leakage current or a change in film quality over time.

In addition, according to the second electronic device manufacturing method, since the nitrogen-containing insulating film is formed on the low dielectric film via the nitrogen-free insulating film, the low dielectric film is directly exposed to the atmosphere containing nitrogen (plasma, etc.) after the low dielectric film is formed. There is no work. This can more reliably suppress the introduction of nitrogen into the low dielectric constant film.

In the second electronic device manufacturing method, the nitrogen-containing insulating film preferably functions as an antireflection film in the step of forming a resist film.

In this way, in the lithography step for forming the concave portion, it is not necessary to separately form an antireflection film made of, for example, an organic material, so that the number of steps can be reduced.

A third electron device manufacturing method according to the present invention comprises the steps of sequentially forming a low dielectric constant film and a second nitrogen-free insulating film on the first nitrogen-free insulating film, and a hole in the low dielectric constant film on which the second nitrogen-free insulating film is formed. And forming an opening in a predetermined region including the region where the hole is formed by applying a chemically amplified resist over the low dielectric constant film on which the hole is formed and exposing and developing the chemically amplified resist. A process of forming the resist film which has it, and the process of etching the low dielectric constant film using this resist film as a mask and forming the recessed part connected with a hole are provided.

According to the third electronic device manufacturing method, holes are formed in the low dielectric constant films each having a nitrogen-free insulating film formed thereon, and then a chemically amplified resist is applied on the low dielectric constant films. Since it is possible to reliably suppress the introduction of nitrogen into the low dielectric constant film, when the chemically amplified resist is applied onto the low dielectric constant film with holes, amines or the like diffuse through the holes, that is, resist poisoning. Can be prevented.

In the first, second or third electronic device manufacturing method, the nitrogen-free insulating film is preferably deposited by the CVD method.

In this case, when a silicon oxide film is formed as a nitrogen-free insulating film, for example, by plasma CVD using TEOS, the density (about 2.3 g / cm 3) of the silicon oxide film is lower than that of low dielectric constant films such as carbon-containing silicon oxide films. Increases. As a result, since the nitrogen-free insulating film made of the silicon oxide film functions as a prevention layer against nitrogen, the introduction of nitrogen into the low dielectric constant film can be more surely suppressed.

In the first, second or third electronic device manufacturing method, it is preferable to further include a step of forming a dummy plug in the hole between the step of forming a hole and the step of forming a resist film.

In this way, for example, a dummy plug made of an organic material can cover the wall surface of the hole including the interface portion between the low dielectric constant film and the nitrogen-free insulating film. That is, since the damage layer of the interface portion or the hole wall surface is covered by the dummy plug, the diffusion of nitrogen from the interface portion or the damage layer into the hole can be suppressed, so that resist poisoning can be prevented more reliably.

A fourth electronic device manufacturing method according to the present invention comprises the steps of forming a low density insulating film having a film density of 1.3 g / cm 3 or less on a low dielectric constant film, forming a hole in a low dielectric constant film having a low density insulating film, and Applying a chemically amplified resist over the formed low dielectric constant film and exposing and developing the applied chemically amplified resist to form a resist film having an opening in a predetermined region including a region where holes are formed; And forming a concave portion connected to the hole by etching the low dielectric constant film using the resist film as a mask.

According to the fourth electronic device manufacturing method, after forming a low density insulating film on the low dielectric constant film, holes are formed in the low dielectric constant film, and then a chemically amplified resist is applied over the low dielectric constant film. As a result, nitrogen introduced into the low dielectric film and nitrogen present in the low density insulating film itself are easily discharged to the outside through the low density insulating film. Therefore, since amines and the like do not concentrate diffused into the holes formed in the low dielectric constant film, when the chemically amplified resist is applied above the low dielectric constant film, the amount of amine and the like per unit volume in the resist near the hole becomes very small. As a result, resist poisoning can be prevented. In the fourth electronic device manufacturing method, the density of the low density insulating film is preferably 0.4 g / cm 3 or more in consideration of the stability of the film.

In the fourth electronic device manufacturing method, it is preferable to include a step of performing heat treatment or irradiating energy waves on the low density insulating film after the step of forming the low density insulating film.

In this way, the film quality of the low density insulating film can be stabilized, and at the same time, more nitrogen in the low dielectric constant film or more nitrogen in the low density insulating film can be discharged to the outside through the low density insulating film. At this time, if the energy waves are electron beams or ultraviolet rays, the above-described effects can be reliably obtained.

In the first, second, third or fourth electronic device manufacturing method, the low dielectric constant film is preferably a carbon-containing silicon oxide film or a porous film.

In this way, the capacitance between wirings can be reliably reduced. As the carbon-containing silicon oxide film, an SiOC film may be used.

(1st embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, the electronic device which concerns on 1st Embodiment of this invention, and its manufacturing method are demonstrated, referring drawings.

1 is a cross-sectional view showing a wiring structure of an electronic device according to the first embodiment.

As shown in FIG. 1, in the lower insulating film 101 formed on the board | substrate 100 which consists of silicon | silicone, for example, the underlayer metal comprised from the tantalum nitride / tantalum laminated film 102a and the copper film 102b, for example. The wiring 102 is formed. On the lower metal wiring 102 and the lower insulating film 101, for example, a first nitrogen-containing insulating film 103 made of a silicon nitride carbide film is formed. On the first nitrogen-containing insulating film 103, a first nitrogen-free insulating film 104 made of, for example, a silicon oxide film is formed. On the first nitrogen-free insulating film 104, a low dielectric constant film 105 made of, for example, a carbon-containing silicon oxide film is formed. On the low dielectric constant film 105, a second nitrogen-free insulating film 106 made of, for example, a silicon oxide film is formed. On the second nitrogen-free insulating film 106, a second nitrogen-containing insulating film 107 made of, for example, a silicon nitride oxide film is formed. In the first nitrogen-containing insulating film 103, the first nitrogen-free insulating film 104, and the low dielectric constant film 105 (lower), a via hole 108 reaching the lower metal wiring 102 is formed. In the low dielectric constant film 105 (upper part), the second nitrogen-free insulating film 106, and the second nitrogen-containing insulating film 107, wiring grooves 109 for connecting with the via hole 108 are formed. In the via hole 108 and the wiring groove 109, the tantalum nitride / tantalum laminated film 110 and the copper film 111 are sequentially formed, whereby the via plug 112 and the upper metal wiring 113 are formed. The via plug 112 connects the lower metal wiring 102 and the upper metal wiring 113.

2 (a) to 2 (f) are cross-sectional views showing respective steps of the method for manufacturing the electronic device according to the first embodiment, that is, the method for manufacturing the electronic device shown in FIG.

First, as shown in Fig. 2A, for example, a lower insulating film 101 made of, for example, a silicon oxide film is formed on a substrate 100 made of silicon, and then an example is given to the lower insulating film 101. For example, the lower metal wiring 102 composed of the tantalum nitride / tantalum laminated film 102a and the copper film 102b is embedded. Specifically, after the lower insulating film 101 is formed, a resist film (not shown) having a lower metal wiring groove pattern is formed on the lower insulating film 101 by a photolithography method, and then the resist film is used as a mask to form a lower insulating film ( Dry etching is carried out to 101 to form wiring grooves. After that, the tantalum nitride / tantalum laminated film 102a and the copper film 102b are sequentially stacked on the lower insulating film 101 so that the wiring grooves are completely filled, and then the laminated film 102a and the copper film outside the wiring grooves are sequentially stacked. 102b is removed with CMP to form lower metallization 102.

Next, as shown in FIG. 2A, the first nitrogen-containing insulating film 103 having a thickness of 50 nm, for example, formed of a silicon nitride carbide film on the lower insulating film 101 and the lower metal wiring 102. To be deposited.

Next, as shown in FIG. 2B, a first nitrogen-free insulating film 104 having a thickness of 50 nm, for example, a silicon oxide film is deposited on the first nitrogen-containing insulating film 103. At this time, a silicon oxide film to be the first nitrogen-free insulating film 104 is deposited by, for example, a plasma CVD method using TEOS. Thereafter, a 450 nm-thick low dielectric constant film 105 made of, for example, a carbon-containing silicon oxide film is deposited on the first nitrogen-free insulating film 104, and then, for example, on the low dielectric constant film 105. A second nitrogen-free insulating film 106 having a thickness of 30 nm made of a silicon oxide film is deposited. At this time, a silicon oxide film to be the second nitrogen-free insulating film 106 is deposited by, for example, a plasma CVD method using TEOS. Thereafter, a second nitrogen-containing insulating film 107 having a thickness of 50 nm, for example, a silicon nitride oxide film is deposited on the second nitrogen-free insulating film 106. The silicon nitride oxide film to be the second nitrogen-containing insulating film 107 here functions as an antireflection film in a later photolithography step. The thickness of the silicon nitride oxide film to be an antireflection film is preferably 60 nm or more and 100 nm or less in a rule larger than 0.18 μm, and preferably 30 nm or more and 70 nm or less in a rule of 0.18 μm or less. When the material film other than the silicon nitride oxide film is used as the second nitrogen-containing insulating film 107, the optical film thickness of the second nitrogen-containing insulating film 107 (= [real part of refractive index of the second nitrogen-containing insulating film 107]] X [film thickness (physical film thickness) of the second nitrogen-containing insulating film 107]), the film of the second nitrogen-containing insulating film 107 so that the limit value in the [real part of the silicon nitride oxide film refractive index] is in the above-mentioned range. It is desirable to set the thickness.

Next, a photoresist is applied on the second nitrogen-containing insulating film 107, and photolithography is performed on the coated photoresist to form a resist film (not shown) having a hole pattern. Thereafter, using the resist film as a mask, dry etching was sequentially performed on the second nitrogen-containing insulating film 107, the second nitrogen-free insulating film 106, the low dielectric constant film 105, and the first nitrogen-free insulating film 104. The photoresist is then removed by ashing. As a result, as shown in FIG. 2C, the via hole 108 is formed.

Next, as shown in FIG. 2 (d), a dummy plug 114 made of, for example, an organic material is formed in the via hole 108. In this embodiment, the dummy plug 114 is formed so that the upper surface of the dummy plug 114 is higher than the interface between the low dielectric constant film 105 and the second nitrogen-free insulating film 106. In the present embodiment, the dummy plug 114 is not an essential process. Thereafter, a photoresist is applied on the second nitrogen-containing insulating film 107, and photolithography (exposure and development) is applied to the coated photoresist, whereby the resist film 115 having a desired groove pattern, specifically, wiring A resist film 115 having an opening 115a corresponding to the groove 109 (see FIG. 2E) is formed. The opening 115a forming region includes a region in which the via hole 108 is formed.

Next, the second nitrogen-containing insulating film 107, the second nitrogen-free insulating film 106, and the low dielectric constant film 105 (upper) are formed using the dummy plug 114 and the resist film 115 having the groove pattern as a mask. Dry etching is performed sequentially. Thereby, as shown in FIG.2 (e), the wiring groove 109 which connects with the via hole 108 is formed. However, after the dry etching described above, the dummy plug 114 and the resist film 115 are removed and washed.

Next, the lower portion of the via hole 108 of the first nitrogen-containing insulating film 103 made of the silicon nitride carbide film is removed by the front etch back. After that, the tantalum nitride / tantalum laminated film 110 and the copper film 111 are sequentially stacked on the second nitrogen-containing insulating film 107 so that the via hole 108 and the wiring groove 109 are completely embedded, and then the wiring groove is formed. (109) The laminated film 110 and the copper film 111 on the outside are removed by CMP. As a result, as shown in FIG. 2F, the via plug 112 is formed in the via hole 108, and the upper metal wiring 113 is formed in the wiring groove 109. In this case, the second nitrogen-containing insulating film 107 and the second nitrogen-free insulating film 106 do not necessarily have to remain at last, and thus, these may be completely or partially removed by the above-described front etch back or CMP.

As described above, according to the first embodiment, the first nitrogen-free insulating film is provided between the low dielectric constant film (carbon-containing silicon oxide film) 105 and the first nitrogen-containing insulating film (silicon nitride carbide film) 103 below it. Since 104 is interposed, resist poisoning can be suppressed for the following three reasons, despite using the first nitrogen-containing insulating film 103.

(1) Since the first nitrogen-containing insulating film 103 and the low dielectric constant film 105 do not directly contact each other, introduction of nitrogen into the low dielectric constant film 105 can be suppressed. As a result, in the lithography process for forming the wiring grooves 109, amines and the like can be diffused into the resist via the via holes 108, that is, resist poisoning can be prevented.

(2) As the first nitrogen-free insulating film 104, for example, a silicon oxide film is formed by a plasma CVD method using TEOS, the density of the silicon oxide film (about 2.3 g / cm &lt; 3 &gt;) is low dielectric constant film 105, i.e. It becomes higher than the density of a carbon containing silicon oxide film. As a result, since the first nitrogen-free insulating film 104 made of the silicon oxide film functions as a prevention layer against nitrogen, the introduction of nitrogen into the low dielectric constant film 105 can be more surely suppressed.

(3) Since the first nitrogen-free insulating film 104 is deposited by the plasma CVD method, the film quality of the first nitrogen-containing insulating film 103, ie, the silicon nitride carbide film, beneath it can be stabilized, so that the first nitrogen-containing insulating film 104 is deposited. Nitrogen contained in the insulating film 103 becomes difficult to be released. Specifically, since the silicon nitride carbide film is exposed to oxygen-containing plasma, the surface portion of the silicon nitride carbide film is oxidized to increase the film density, and as a result, the surface portion serves to prevent diffusion of nitrogen in the silicon nitride carbide film. Therefore, introduction of nitrogen into the low dielectric constant film 105 can be suppressed more reliably.

In the first embodiment, the first nitrogen-containing insulating film 103 (for example, silicon nitride carbide film) having a good film quality can be formed under the low dielectric constant film 105 while suppressing resist poisoning by the above-described effects. have. Therefore, it is possible to prevent the increase of the leakage current or the change in film quality over time. Since the silicon nitride carbide film to be the first nitrogen-containing insulating film 103 does not contain oxygen, when the first nitrogen-containing insulating film 103 is deposited on the copper film 102b constituting the lower metal wiring 102. The copper film 102b does not oxidize.

According to the first embodiment, the second nitrogen-free insulating film 106 is interposed between the low dielectric constant film (carbon-containing silicon oxide film) 105 and the second nitrogen-containing insulating film (silicon nitride oxide film) 107 thereon. Since it interposes, resist poisoning can be suppressed for three reasons mentioned later, although the 2nd nitrogen containing insulating film 107 is used.

(1) Since the second nitrogen-containing insulating film 107 and the low dielectric constant film 105 do not directly contact each other, introduction of nitrogen into the low dielectric constant film 105 can be suppressed. As a result, in the lithography process for forming the wiring grooves 109, amines and the like can be diffused into the resist via the via holes 108, that is, resist poisoning can be prevented.

(2) As the second nitrogen-free insulating film 106, a silicon oxide film is formed by, for example, plasma CVD using TEOS, so that the density of the silicon oxide film (about 2.3 g / cm &lt; 3 &gt;) is low dielectric constant film 105, i.e. It becomes higher than the density of a carbon containing silicon oxide film. As a result, since the second nitrogen-free insulating film 106 made of the silicon oxide film functions as a prevention layer against nitrogen, the introduction of nitrogen into the low dielectric constant film 105 can be more surely suppressed.

(3) Since the second nitrogen-containing insulating film 107 is formed on the low dielectric constant film 105 via the second nitrogen-free insulating film 106, an atmosphere containing nitrogen after the low dielectric constant film 105 is formed (plasma) Etc.) does not directly expose the low dielectric constant film 105. This can more reliably suppress the introduction of nitrogen into the low dielectric constant film 105.

In the first embodiment, the second nitrogen-containing insulating film 107 (for example, silicon nitride carbide film) having a good film quality can be formed above the low dielectric constant film 105 while suppressing resist poisoning by the above-described effects. have. Therefore, it is possible to prevent the increase of the leakage current or the change in film quality over time. In addition, since the silicon nitride oxide film having an antireflection effect is used as the second nitrogen-containing insulating film 107, an antireflection film made of, for example, an organic material during the lithography process for forming the via hole 108 and the wiring groove 109. It is not necessary to form separately so that the number of processes can be reduced. At this time, the selection ratio of the second nitrogen-containing insulating film 107 to the resist is also easily secured, so that the etching of the second nitrogen-containing insulating film 107 is easy. As described above, since the antireflection film is not required to be applied when the wiring grooves 109 are formed, the upper surface of the dummy plug 114 can be set to the same height as the bottom surface of the wiring grooves 109 to be formed. Thereby, when etching for forming the wiring grooves 109 is performed, a situation in which a fence-shaped remainder is generated in the vicinity of the via hole 108 in the bottom surface of the wiring grooves 109 can be prevented.

According to the first embodiment, the first nitrogen-containing insulating film 103 remains under the via hole 108, in other words, above the lower metal wiring 102 until the formation of the wiring groove 109 is completed. . As a result, damage to the lower metal wiring 102 due to etching or ashing (for example, oxidation of the surface of the lower metal wiring 102) can be reduced.

Further, according to the first embodiment, the dummy plug 114 is formed in the via hole 108 before the photolithography for forming the wiring groove 109 is performed. As a result, the dummy plug 114 can cover the wall surface of the via hole 108 including the interface portion between the low dielectric constant film 105 and the first and second nitrogen-free insulating films 104 and 106. That is, since the damage layer of the interface portion or the wall of the via hole 108 is covered with the dummy plug 114, the diffusion of nitrogen from the interface portion or the damage layer into the via hole 108 can be suppressed, so that resist poisoning is more reliably performed. It can prevent. In addition, by forming the dummy plug 114 in the via hole 108, the surface of the resist to be applied can be planarized, so that the accuracy of the pattern obtained by photolithography can be improved.

Here, in the first embodiment, a silicon nitride oxide film having an antireflection effect is used as the second nitrogen-containing insulating film 107, but instead of nitrogen containing nitrogen (exactly, nitrogen contained in the film is 1 × 10 ¹⁹ atoms / Other types of insulating films (cm 3 or more) may be used. For example, when the silicon nitride film is used as the second nitrogen-containing insulating film 107, the second nitrogen-containing insulating film 107 may be used as a hard mask in an etching process for forming the via hole 108 or the wiring groove 109. . This is effective in the case of using a porous film, a film having a higher carbon-containing concentration (that is, an insulating film having a lower dielectric constant) or the like as the low dielectric film 105. Alternatively, a silicon nitride carbide film (SiCN film) may be used as the second nitrogen-containing insulating film 107.

In addition, in the first embodiment, a silicon nitride carbide film is used as the first nitrogen-containing insulating film 103, but another type of insulating film containing nitrogen, for example, a silicon nitride film (SiN film) may be used.

In the first embodiment, the silicon oxide film is used as the first nitrogen-free insulating film 104 or the second nitrogen-free insulating film 106, but instead of nitrogen (exactly, nitrogen contained in the film is Other kinds of insulating films (less than 1 × 10 ¹⁹ atoms / cm 3), for example, oxygenated silicon carbide films (SiCO films) or silicon carbide films (SiC films) may be used.

In addition, in the first embodiment, for example, an SiOC film can be used as the carbon-containing silicon oxide film to be the low dielectric constant film 105.

In the first embodiment, the low dielectric constant film 105 (lower surface) and the first nitrogen-free insulating film 104 (upper surface) directly contact each other, but the low dielectric constant film 105 and the first nitrogen-free insulating film are directly in contact with each other. Another nitrogen-free insulating film may be further formed between the 104 and 104 layers. Similarly, the low dielectric constant film 105 (upper surface) and the second nitrogen-free insulating film 106 (lower surface) are in direct contact with each other, but are further provided between the low dielectric constant film 105 and the second nitrogen-free insulating film 106. Another nitrogen-free insulating film may be formed.

In the first embodiment, the formation of the wiring structure composed of the lower metal wiring 102 and the upper metal wiring 113 connected by the via plug 112 is intended, but the present invention is not limited thereto. For example, it is a matter of course to form a memory cell structure composed of a transistor (its diffusion layer) and a capacitor (its lower electrode) connected by a contact plug.

Comparative Example

Hereinafter, as a comparative example of the first embodiment, an electronic device having an inter-wire insulating film structure in which a low dielectric constant film and a nitrogen-containing insulating film directly contact each other, and a manufacturing method thereof will be described (Higashi Kazuyuki et al., Proceedings of the 2002 International Interconnect Technology Conference, pp. 15-17).

3 is a cross-sectional view showing a wiring structure of an electronic device according to a comparative example.

As shown in FIG. 3, in the first insulating film 21 formed on the silicon substrate (not shown), the lower metal wiring 22 formed of the tantalum nitride / tantalum laminated film 22a and the copper film 22b is formed. do. On the lower metal wiring 22 and the first insulating film 21, a second insulating film (nitrogen-containing insulating film) 23 made of a silicon nitride carbide film is formed. On the second insulating film 23, a third insulating film (low dielectric constant film) 24 made of a carbon-containing silicon oxide film is formed. On the third insulating film 24, a fourth insulating film 25 made of a silicon oxide film is formed. The fourth insulating film 25 is formed using a plasma free of nitrogen contamination. In the second insulating film 23 and the third insulating film 24 (at least in the bottom), a via hole 26 extending to the lower metal wiring 22 is formed. In the third insulating film 24 (upper part) and the fourth insulating film 25, wiring grooves 27 for connecting with the via holes 26 are formed. Tantalum nitride / tantalum laminated film 28 and copper film 29 are sequentially formed in via hole 26 and wiring groove 27, thereby forming via plug 30 and upper metal wiring 31. The via plug 30 connects the lower metal wiring 22 and the upper metal wiring 31.

4 (a) to 4 (f) are cross-sectional views showing respective steps of the method for manufacturing the electronic device according to the comparative example, that is, the method for manufacturing the electronic device shown in FIG.

First, as shown in FIG. 4A, after the first insulating film 21 is formed on a silicon substrate (not shown), the tantalum nitride / tantalum laminated film 22a and the copper film are formed on the first insulating film 21. An underlayer metal wiring 22 composed of 22b is embedded.

Next, as shown in FIG.4 (b), after depositing the 2nd insulating film 23 which consists of a silicon nitride carbide film on the 1st insulating film 21 and the lower metal wiring 22, a 2nd insulating film Plasma treatment is performed on the 23 to stabilize the film quality of the second insulating film 23. Subsequently, a third insulating film 24 made of a carbon-containing silicon oxide film is deposited on the second insulating film 23. Thereafter, a fourth insulating film 25 made of a silicon oxide film is deposited on the third insulating film 24 by the plasma CVD method, and then an organic antireflection film 32 is formed on the fourth insulating film 25. Here, the fourth insulating film 25 is formed using a plasma free of nitrogen contamination after pretreatment without nitrogen contamination is performed on the third insulating film 24 to be the base.

Next, a photoresist is applied on the organic antireflection film 32, and photolithography is performed on the coated photoresist to form a resist film (not shown) having a hole pattern. After that, the organic anti-reflective film 32, the fourth insulating film 25 and the third insulating film 24 are sequentially subjected to dry etching using the resist film as a mask, and then the photoresist and the organic anti-reflective film 32 are removed by ashing. . As a result, as shown in FIG. 4C, the via hole 26 is formed.

Next, as shown in FIG.4 (d), after depositing the lower resist film 33 on the 4th insulating film 25 so that the via hole 26 may be fully filled, SOG (on the lower resist film 33 is deposited). Spin on Glass) film 34 is formed. Thereafter, a photoresist is applied on the SOG film 34, and photolithography is performed on the coated photoresist, thereby forming the upper resist film 35 having a desired groove pattern, specifically, the wiring groove 27 (Fig. An upper resist film 35 having an opening 35a corresponding to 4 (e)) is formed.

Next, dry etching is performed on the SOG film 34 using the upper resist film 35 having the groove pattern as a mask. Subsequently, the lower resist film 33, the fourth insulating film 25 and the third insulating film 24 (upper) are sequentially dry-etched using the patterned SOG film 34 as a mask. As a result, as shown in FIG. 4E, a wiring groove 27 to be connected to the via hole 26 is formed. However, after the dry etching described above, the upper resist film 35, the SOG film 34 and the lower resist film 33 are removed and washed.

Next, the lower portion of the via hole 26 in the second insulating film 23 is removed by the front etch back. After that, the tantalum nitride / tantalum laminated film 28 and the copper film 29 are sequentially deposited on the fourth insulating film 25 so that the via holes 26 and the wiring grooves 27 are completely filled with the wiring grooves 29. ) The laminated film 28 and copper film 29 on the outside are removed by CMP. As a result, as shown in FIG. 4F, the via plug 30 is formed in the via hole 26, and the upper metal wiring 31 is formed in the wiring groove 27.

As described above, in the comparative example, the resist poisoning can be suppressed by stabilizing the second insulating film 23, that is, the silicon nitride carbide film by plasma treatment.

However, in the comparative example, the third insulating film (low dielectric constant) which is in direct contact with the film from the silicon nitride carbide film (second insulating film 23) due to unstable nitrogen remaining in the silicon nitride carbide film or a nonuniform difference in plasma treatment. Nitrogen is diffused into the film 24). Therefore, in the lithography process for forming the wiring groove 27, the amine or the like is diffused into the resist via the via hole 26, that is, the resist poisoning cannot be sufficiently prevented.

In the comparative example, after the pretreatment without nitrogen contamination, the fourth insulating film 25, that is, silicon oxide film, is formed on the third insulating film (low dielectric constant film) 24 using a plasma free of nitrogen contamination, thereby resist poisoning. Promote the suppression of However, since the silicon oxide film has no antireflection effect, it is necessary to form the organic antireflection film 32 when lithographically forming a pattern for forming the via hole 26. However, since the coating film thickness of the organic antireflection film 32 is large, and it is difficult to secure the selectivity of the organic antireflection film 32 with respect to the photoresist, etching for forming the via hole 26 becomes difficult. As described above, when the pattern for forming the wiring groove 27 is formed by lithography, the lower resist film 33, the SOG film 34, and the upper resist film 35 are used in combination, so that the wiring groove is used. Etching for forming (27) becomes difficult. In this case, when the dimension difference or the alignment difference occurs in the lithography process, the SOG film 34 is used, so that pattern reproduction becomes difficult to perform. This is because unlike the resist film, the SOG film 34 cannot be easily removed by ashing or the like. When the organic anti-reflection film is formed instead of the combination of the lower resist film 33, the SOG film 34, and the upper resist film 35, the same problem as in the etching for forming the above-described via hole 26 occurs. do.

By the way, when a low dielectric constant film having a lower dielectric constant (specifically, a relative dielectric constant? Of less than 2.8) is used, a nitrogen-containing insulating film such as a silicon nitride film is formed on the low dielectric constant film and the nitrogen-containing insulating film is etched at the time of etching. The process used as a hard mask is effective in that the low selectivity for the photoresist can be realized and the ashing damage can be prevented. However, in the comparative example, only the structure and the process of forming the silicon oxide film on the low dielectric constant film without using the plasma containing nitrogen are not allowed. In other words, since the nitrogen-containing insulating film cannot be formed on the low dielectric constant film, It is disadvantageous when considering insulation film low dielectric constant. Moreover, in the comparative example, since the dielectric constant of the silicon oxide film mentioned above is about 4.2 and there exists a problem that the capacitance between wirings will increase, it is disadvantageous also from the viewpoint of the low dielectric constant required for the insulating film in the future.

In contrast, according to the first embodiment, the low dielectric constant film 105 is interposed between the low dielectric constant film 105 and the first nitrogen-containing insulating film 103 below. The remarkable effect that all the problems of the comparative example described above are solved by the structure (see FIG. 1) which interposes the 2nd nitrogen-free insulating film 106 between the upper 2nd nitrogen containing insulating films 107 above is solved. You can get it.

(2nd embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, the electronic device which concerns on 2nd Embodiment of this invention, and its manufacturing method are demonstrated, referring drawings.

5 is a cross-sectional view showing a wiring structure of an electronic device according to the second embodiment.

As shown in FIG. 5, in the lower insulating film 201 formed on the board | substrate 200 which consists of silicon | silicone, for example, the underlayer metal comprised from the tantalum nitride / tantalum laminated film 202a and the copper film 202b, for example. The wiring 202 is formed. On the lower metal wiring 202 and the lower insulating film 201, a nitrogen-containing insulating film 203 made of, for example, a silicon nitride carbide film is formed. On the nitrogen-containing insulating film 203, a low dielectric constant film 204 made of, for example, a carbon-containing silicon oxide film is formed. On the low dielectric constant film 204, a low density insulating film (low density cap film) 205 having a film density of 1.3 g / cm 3 or less is formed. In the nitrogen-containing insulating film 203 and the low dielectric constant film 204 (lower portion), a via hole 206 extending to the lower metal wiring 202 is formed. In the low dielectric constant film 204 (upper part) and the low density cap film 205, wiring grooves 207 for connecting with the via holes 206 are formed. In the via hole 206 and the wiring groove 207, a tantalum nitride / tantalum laminated film 208 and a copper film 209 are sequentially formed, thereby forming a via plug 210 and an upper metal wiring 211.

6 (a) to 6 (f) are cross-sectional views showing respective steps of the method for manufacturing the electronic device according to the second embodiment, that is, the method for manufacturing the electronic device shown in FIG.

First, as shown in Fig. 6A, a lower insulating film 201 made of, for example, a silicon oxide film is formed on a substrate 200 made of silicon, for example, and then an example is placed on the lower insulating film 201. For example, the lower metal wiring 202 composed of the tantalum nitride / tantalum laminated film 202a and the copper film 202b is embedded.

Next, as shown in FIG. 6B, a nitrogen-containing insulating film 203 having a thickness of 50 nm formed of, for example, a silicon nitride carbide film or a silicon nitride film on the lower insulating film 201 and the lower metal wiring 202. ) Is deposited. Thereafter, a low dielectric constant film 204 having a thickness of 450 nm, for example, made of a carbon-containing silicon oxide film is deposited on the nitrogen-containing insulating film 203. Subsequently, a low density cap film 205 having a film density of 1.3 g / cm 3 or less and a thickness of 50 nm is formed on the low dielectric constant film 204. Thereafter, for example, an organic material is coated on the low density cap film 205 to form the first antireflection film 212.

Next, a photoresist is applied on the first antireflection film 212, and photolithography is performed on the coated photoresist to form a resist film (not shown) having a hole pattern. Thereafter, the first anti-reflection film 212, the low density cap film 205, and the low dielectric constant film 204 are sequentially dry-etched using this resist film as a mask, and then the photoresist and the first anti-reflection film 212 are subjected to ashing. Remove As a result, as shown in FIG. 6C, the via hole 206 is formed.

Next, as shown in FIG. 6D, for example, an organic material is coated on the low density cap film 205 so that the via hole 206 is completely embedded to form the second antireflection film 213. After that, by applying a photoresist on the second antireflection film 213 and subjecting the coated photoresist to photolithography (exposure and development), a resist film 214 having a desired groove pattern, specifically, a wiring groove ( A resist film 214 having an opening 214a corresponding to 207 (see FIG. 6E) is formed. In this case, the opening 214a forming region includes a region in which the via hole 206 is formed.

Next, using the resist film 214 having the groove pattern as a mask, dry etching is sequentially performed on the second antireflection film 213, the low density cap film 205, and the low dielectric constant film 204 (upper). As a result, as shown in FIG. 6E, a wiring groove 207 connected to the via hole 206 is formed. However, after the dry etching described above, the remaining second anti-reflection film 213 and the resist film 214 are removed and washed.

Next, the lower portion of the via hole 206 of the nitrogen-containing insulating film 203 made of the silicon nitride carbide film is removed by an entire etch back. After that, the tantalum nitride / tantalum laminated film 208 and the copper film 209 are sequentially deposited on the low density cap film 205 so that the via hole 206 and the wiring groove 207 are completely embedded, and then the wiring groove 207 is formed. The outer laminated film 208 and copper film 209 are removed by CMP. As a result, as shown in FIG. 6F, the via plug 210 is formed in the via hole 206 and the upper metal wiring 211 is formed in the wiring groove 207. The low-density cap film 205 does not necessarily have to be finally left in the final step, and thus, these may be completely or partially removed by the above-described entire etch back or CMP.

As described above, according to the second embodiment, the low density cap film 205 is formed on the low dielectric constant film (carbon-containing silicon oxide film) 204. Therefore, nitrogen introduced into the low dielectric constant film 204, nitrogen in the nitrogen-containing insulating film 203, or nitrogen present in the low density cap film 205 itself are easily discharged to the outside through the low density cap film 205. As a result, since amines and the like do not concentrate in the via holes 206 formed in the low dielectric constant film 204, such as amines per unit volume in the resist near the via holes 206 in the lithography process for forming the wiring grooves 207. The amount is very small, and as a result, resist poisoning can be prevented.

In the second embodiment, the nitrogen-containing insulating film 203 (for example, silicon nitride carbide film) having a good film quality can be formed under the low dielectric constant film 204 while suppressing resist poisoning. Therefore, it is possible to prevent the increase of the leakage current or the change in film quality over time. Since the silicon nitride carbide film to be the nitrogen-containing insulating film 203 does not contain oxygen, when the nitrogen-containing insulating film 203 is deposited on the copper film 202b constituting the lower metal wiring 202, the copper film 202b. ) Is not oxidized.

According to the second embodiment, the nitrogen-containing insulating film 203 remains under the via hole 206, in other words, above the lower metal wiring 202 until the formation of the wiring groove 207 is completed. Therefore, damage to the lower metal wiring 202 (for example, oxidation of the surface of the lower metal wiring 202) due to etching or ashing can be reduced.

According to the second embodiment, the second antireflection film 213 is embedded in the via hole 206 before the photolithography for forming the wiring groove 207 is performed. Thus, the second anti-reflection film 213 can cover the via hole 206 wall. In other words, since the damage layer on the wall of the via hole 206 is covered with the second anti-reflection film 213, the diffusion of nitrogen from the damaged layer into the via hole 206 can be suppressed, so that resist poisoning can be prevented more reliably. .

In the second embodiment, the kind of the insulating film that can be used as the low density cap film 205 is not particularly limited as long as the film density is 1.3 g / cm 3 or less. However, when the low density cap film 205 uses a film having a low dielectric constant as well as a density, for example, a porous film, the inter-wire capacitance can be reduced. Specifically, a porous membrane such as an HSQ (hydrogen silsesquioxane) membrane or an XLK membrane (density: about 0.9 g / cm 3) manufactured by Dow Corning may be used. In addition, when the low density cap film 205 contains nitrogen, the film quality of the low density cap film 205 becomes good, so that an increase in leakage current or a change in film quality over time can be prevented. On the other hand, it is preferable that the low density cap film 205 does not contain carbon. This is because when ashing is performed on a carbon-containing film such as an SiOC film, carbon is detached from the film and leakage current easily flows. The density of the low density cap film 205 is preferably 0.4 g / cm 3 or more in view of the stability of the film.

In the second embodiment, in the case of using a porous film such as the above-described HSQ film as the low density cap film 205, the low density cap film 205 after the low density cap film 205 is formed, for example. It is preferable to perform heat treatment at about 300 to 400 ° C or to perform EB (electron beam) curing or DUV (ultraviolet ray) curing. In this manner, the film quality of the low density cap film 205 can be stabilized, and the nitrogen in the nitrogen-containing insulating film 203, the nitrogen in the low dielectric constant film 204, or the nitrogen in the low density cap film 205 are replaced with the low density cap film 205. More to the outside. Instead of the EB or DUV treatment, the low density cap film 205 may be irradiated with light or other energy waves other than DUV, which can stabilize the film quality of the low density cap film 205.

In the second embodiment, as the low dielectric constant film 204, for example, a porous film such as a carbon-containing silicon oxide film such as an SiOC film, a Silk film, or an MSQ (methyl silsesquioxane) film can be used.

In the second embodiment, the formation of the wiring structure composed of the lower metal wiring 202 and the upper metal wiring 211 connected by the via plug 210 is intended, but the present invention is not limited thereto. For example, it is a matter of course that the memory cell structure composed of a transistor (its diffusion layer) and a capacitor (its lower electrode) connected by a contact plug can be used.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an electronic device and a method for manufacturing the same, and when applied to the formation of a multi-layered wiring structure, for example, a remarkable effect of preventing the occurrence of resist poisoning in the lithography process can be obtained.

Claims (43)

A low dielectric constant film having holes, A nitrogen-free insulating film formed under the low dielectric constant film; And a nitrogen-containing insulating film formed under the nitrogen-free insulating film. The method of claim 1, The hole penetrates each of the nitrogen-free insulating film and the nitrogen-containing insulating film, Further comprising a lower layer wiring connected to the hole below the hole, And the upper surface of the lower layer wiring except for the hole connection region is covered with the nitrogen-containing insulating film. The method of claim 1, And a lower surface of the low dielectric constant film and an upper surface of the nitrogen-free insulating film. The method of claim 1, The low dielectric constant film is an electronic device, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 4, wherein The carbon-containing silicon oxide film is an electronic device, characterized in that the SiOC film. A low dielectric constant film having holes, A nitrogen-free insulating film formed over the low dielectric constant film; And a nitrogen-containing insulating film formed over the nitrogen-free insulating film. The method of claim 6, The nitrogen-containing insulating film is an antireflection film, And at least an upper portion of the nitrogen-containing insulating film, the nitrogen-free insulating film, and the low dielectric constant film is formed with a recess connecting the hole. The method of claim 6, And an upper surface of the low dielectric constant film and a lower surface of the nitrogen-free insulating film. The method of claim 6, The low dielectric constant film is an electronic device, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 9, The carbon-containing silicon oxide film is an electronic device, characterized in that the SiOC film. A low dielectric constant film having holes, A first nitrogen-free insulating film formed under the low dielectric constant film; A second nitrogen-free insulating film formed over the low dielectric constant film, The hole penetrates the first nitrogen-free insulating layer, And at least one of the second nitrogen-free insulating film and the low dielectric constant film is formed with a recess connecting the hole. The method of claim 11, And a lower surface of the low dielectric constant film and an upper surface of the first nitrogen-free insulating film. The method of claim 11, And an upper surface of the low dielectric constant film and a lower surface of the second nitrogen-free insulating film. The method of claim 11, The low dielectric constant film is an electronic device, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 14, The carbon-containing silicon oxide film is an electronic device, characterized in that the SiOC film. A low dielectric constant film having holes, And a low density insulating film having a film density of 1.3 g / cm 3 or less formed above the low dielectric constant film. The method of claim 16, And said low density insulating film contains nitrogen. The method of claim 16, And a nitrogen-containing insulating film formed under the low dielectric constant film. The method of claim 16, The low dielectric constant film is an electronic device, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 19, The carbon-containing silicon oxide film is an electronic device, characterized in that the SiOC film. Sequentially forming a nitrogen-free insulating film and a low dielectric constant film on the nitrogen-containing insulating film; Forming a hole in the low dielectric constant film; By applying a chemically amplified resist on the low-k dielectric film formed with the holes, and exposing and developing the applied chemically amplified resist, a resist film having an opening in a predetermined region including the region where the hole is formed. Forming process, And etching the low dielectric constant film with the resist film as a mask to form a recess connecting the hole. The method of claim 21, And the nitrogen-containing insulating film is formed to cover the lower layer wiring. The method of claim 21, The step of forming the hole includes the step of forming the hole in the low dielectric constant film and the nitrogen-free insulating film, And removing the nitrogen-containing insulating film below the hole after the step of forming the concave portion. The method of claim 21, And the nitrogen-free insulating film is deposited by CVD. The method of claim 21, And forming a dummy plug in the hole between the step of forming the hole and the step of forming the resist film. The method of claim 21, The low dielectric constant film is an electronic device manufacturing method, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 26, The carbon-containing silicon oxide film is an electronic device manufacturing method, characterized in that the SiOC film. Sequentially forming a nitrogen-free insulating film and a nitrogen-containing insulating film on the low dielectric constant film; Forming holes in the low dielectric constant film on which the nitrogen-free insulating film and the nitrogen-containing insulating film are formed; A chemically amplified resist is applied over the low dielectric constant film on which the hole is formed, and exposure and development are performed on the applied chemically amplified resist to form a resist film having an opening in a predetermined region including the region where the hole is formed. Forming process, And etching the low dielectric constant film with the resist film as a mask to form a recess connecting the hole. The method of claim 28, In the step of forming the resist film, the nitrogen-containing insulating film functions as an antireflection film. The method of claim 28, And the nitrogen-free insulating film is deposited by CVD. The method of claim 28, And forming a dummy plug in the hole between the step of forming the hole and the step of forming the resist film. The method of claim 28, The low dielectric constant film is an electronic device manufacturing method, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 32, The carbon-containing silicon oxide film is an electronic device manufacturing method, characterized in that the SiOC film. Sequentially forming a low dielectric constant film and a second nitrogen-free insulating film on the first nitrogen-free insulating film; Forming a hole in the low dielectric constant film on which the second nitrogen-free insulating film is formed; A chemically amplified resist is applied over the low dielectric constant film on which the hole is formed, and exposure and development are performed on the applied chemically amplified resist to form a resist film having an opening in a predetermined region including the region where the hole is formed. Forming process, And etching the low dielectric constant film with the resist film as a mask to form a recess connecting the hole. The method of claim 34, wherein And the first nitrogen-free insulating film and the second nitrogen-free insulating film are deposited by a CVD method. The method of claim 34, wherein And forming a dummy plug in the hole between the step of forming the hole and the step of forming the resist film. The method of claim 34, wherein The low dielectric constant film is an electronic device manufacturing method, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 37, The carbon-containing silicon oxide film is an electronic device manufacturing method, characterized in that the SiOC film. Forming a low density insulating film having a film density of 1.3 g / cm 3 or less on the low dielectric constant film; Forming a hole in the low dielectric constant film on which the low density insulating film is formed; A chemically amplified resist is applied over the low dielectric constant film on which the hole is formed, and exposure and development are performed on the applied chemically amplified resist to form a resist film having an opening in a predetermined region including the region where the hole is formed. Forming process, And etching the low dielectric constant film with the resist film as a mask to form a recess connecting the hole. The method of claim 39, And a step of subjecting said low density insulating film to a heat treatment or irradiating energy waves after said step of forming said low density insulating film. The method of claim 40, The energy wave is an electron device manufacturing method, characterized in that the electron beam or ultraviolet. The method of claim 39, The low dielectric constant film is an electronic device manufacturing method, characterized in that the carbon-containing silicon oxide film or a porous film. The method of claim 42, The carbon-containing silicon oxide film is an electronic device manufacturing method, characterized in that the SiOC film.