Formation of interlayer insulating film and semiconductor device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

TECHNICAL minute Field of the Invention field]

The present invention relates to a method for forming an interlayer insulating film, and more particularly to a method for forming a low dielectric constant interlayer insulating film required for a high-density semiconductor device. In recent years, the density of semiconductor devices has been increasing, and the intervals between wirings have become narrower accordingly. Therefore, since the electric capacity between the wirings increases, an interlayer insulating film having a low dielectric constant is desired.

【0002】

[Conventional technology]

In recent years, as the density and integration of LSI devices have increased, wiring has become finer and more multi-layered. Along with this, the wiring capacity between wirings is also increasing. Since the operating speed is significantly reduced due to the increase in the wiring capacity, the demand for improvement is increasing. As a remedy, SiO currently used as an interlayer insulating film₂A method of reducing the electric capacity between wirings by using a low dielectric constant interlayer insulating film having a smaller dielectric constant than that of the wiring is being studied.

【0003】

Typical low dielectric constant interlayer insulating films currently being studied include SiOF films and organic low dielectric constant insulating films. These membranes will be briefly described below. SiOF film The SiOF film uses a reaction gas containing F to form a SiOF film.₂It is formed by substituting a part of the Si-O bond in the Si-F bond with a Si-F bond, and its relative permittivity decreases monotonically as the concentration of F in the film increases.

【0004】

Several methods have been reported as methods for forming a SiOF film (see Monthly Semicondoctor Word February 1996, p82). One of the most promising ones at present is SiH as a raw material gas.₄, O₂, Ar, SiF₄, Is used to form a SiOF film by a high-density plasma CVD method (HDPCVD method). The relative permittivity of the SiOF film formed by this method is 3.1 to 4.0 (depending on the F concentration in the film), and SiO is conventionally used as an interlayer insulating film.₂The relative permittivity of is smaller than 4.0.

【0005】

Organic low dielectric constant insulating film An organic low dielectric constant insulating film is attracting attention as an insulating film having a smaller dielectric constant (3.0 or less) than the SiOF film. Table 1 shows some of the organic low dielectric constant insulating films reported so far, their relative permittivity, and their thermal decomposition temperature.

【0006】

[table 1]

<img file="JP2000332011A_D0001.tif" />【0007】

[Problems to be Solved by the Invention]

However, the above SiOF film has a drawback that the hygroscopicity decreases as the F concentration in the film increases. The decrease in moisture absorption resistance becomes a serious problem because it increases the dielectric constant of the film and further affects the transistor characteristics and the adhesion of the upper barrier metal layer.

【0008】

Further, the above-mentioned organic low dielectric constant insulating film includes a Si film and SiO.₂Poor adhesion to the film and easy peeling. Further, there is a drawback that the thermal decomposition temperature is around 400 ° C and the heat resistance is poor. The drawback of poor heat resistance becomes a problem when the wafer is annealed at a high temperature. The present invention has been created in view of the problems of the prior art, and provides a method for forming a low dielectric constant interlayer insulating film having good hygroscopicity and heat resistance, and a semiconductor device using the same. The purpose.

【0009】

[Means for solving problems]

The problem is TEOS, which is the first invention, and O at a first concentration lower than the concentration required for oxidation of the TEOS.₃The first SiO having porosity on the object to be formed by the chemical vapor deposition method in which and is contained in the reaction gas.₂A film is formed with TEOS and a second concentration of O sufficient to oxidize the TEOS.₃By the chemical vapor deposition method in which and is contained in the reaction gas, the first SiO₂Second SiO on the membrane₂This is solved by the method of forming the interlayer insulating film that forms the film.

【0010】

Alternatively, according to the second invention, an underlying insulating film is formed on the object to be formed, and TEOS and O having a first concentration lower than the concentration required for oxidation of the TEOS are formed.₃A third SiO having porosity on the underlying insulating film by a chemical vapor deposition method in which and is contained in the reaction gas.₂A film is formed with TEOS and a second concentration of O sufficient to oxidize the TEOS.₃By the chemical vapor deposition method in which and is contained in the reaction gas, the third SiO₂Fourth SiO on the membrane₂This is solved by the method of forming the interlayer insulating film that forms the film.

【0011】

Alternatively, the second SiO according to the first invention, which is the third invention.₂The membrane or the fourth SiO described in the second invention.₂After forming the film, the second or fourth SiO₂The solution is solved by the method for forming an interlayer insulating film according to the first invention or the second invention, wherein the surface of the film is polished by a CMP method (chemical mechanical polishing method) and flattened. Alternatively, the second SiO according to the first invention, which is the fourth invention.₂The membrane or the fourth SiO described in the second invention.₂After polishing the surface of the film by the CMP method and flattening it, the second or fourth SiO₂The solution is solved by the method for forming an interlayer insulating film according to the third invention, which comprises forming a cover insulating film on the film.

【0012】

Alternatively, the fifth invention, TEOS and O at a concentration lower than the concentration required for oxidation of the TEOS.₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porosity on the object to be formed₂SiO that forms a film and has the porosity₂A layer in which a damascene groove leading to the object to be formed is formed in a film, a sidewall insulating film is formed on a side portion of the damascene groove, a metal film is embedded in the damascene groove, and a barrier metal layer is formed on the metal film. The problem is solved by the method of forming the insulating film.

【0013】

Alternatively, according to the sixth invention, an underlying insulating film is formed on the object to be formed, and TEOS and O having a concentration lower than the concentration required for oxidation of the TEOS are formed.₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porousness on the underlying insulating film₂A film is formed, and the underlying insulating film and the porous SiO₂A layer in which a damascene groove leading to the object to be formed is formed in a film, a sidewall insulating film is formed on a side portion of the damascene groove, a metal film is embedded in the damascene groove, and a barrier metal layer is formed on the metal film. The problem is solved by the method of forming the insulating film.

【0014】

Alternatively, the seventh invention, Cl (chlorine) plasma treatment of the object to be formed, TEOS and O₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porosity on the object to be formed₂This is solved by the method of forming the interlayer insulating film that forms the film. Alternatively, the eighth invention, that is, an underlying insulating film is formed on the object to be formed, and the underlying insulating film is treated with Cl (chlorine) plasma to treat TEOS and O.₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porousness on the underlying insulating film₂This is solved by the method of forming the interlayer insulating film that forms the film.

【0015】

Alternatively, the ninth invention, the SiO having the porous property.₂After forming the film, SiO with the porosity₂A first insulating film is formed on the film, and the first insulating film is made of the porous SiO.₂The solution is solved by the method for forming an interlayer insulating film according to the seventh invention or the eighth invention, which is characterized in that the film is flattened by etching to the extent that a part of the film is removed.

【0016】

Alternatively, after flattening the first insulating film, which is the tenth invention, the SiO has porosity on the first insulating film and on the first insulating film.₂The solution is solved by the method for forming an interlayer insulating film according to a ninth aspect of the invention, wherein a cover insulating film is formed on a part of the film. Alternatively, the eleventh invention, in which the object to be formed is treated with Cl (chlorine) plasma, is treated with TEOS and O.₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porosity on the object to be formed₂SiO that forms a film and has the porosity₂A layer in which a damascene groove leading to the object to be formed is formed in a film, a sidewall insulating film is formed on a side portion of the damascene groove, a metal film is embedded in the damascene groove, and a barrier metal layer is formed on the metal film. The problem is solved by the method of forming the insulating film.

【0017】

Alternatively, according to the twelfth invention, an underlying insulating film is formed on the object to be formed, and the underlying insulating film is treated with Cl (chlorine) plasma to treat TEOS and O.₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porousness on the underlying insulating film₂A film is formed, and the underlying insulating film and the porous SiO₂A layer in which a damascene groove leading to the object to be formed is formed in a film, a sidewall insulating film is formed on a side portion of the damascene groove, a metal film is embedded in the damascene groove, and a barrier metal layer is formed on the metal film. The problem is solved by the method of forming the insulating film.

【0018】

Alternatively, the sidewall insulating film according to the thirteenth invention has the porousness after forming the damascene groove.₂A second insulating film is formed on the film, the side portion of the damascene groove, and the bottom portion of the damascene groove, and the second insulating film is formed on the side portion of the damascene groove. A fifth invention, a sixth invention, characterized in that the insulating film remains and the surface of the object to be formed is formed by etching heterogeneously to such an extent that it is exposed at the bottom of the damascene groove. It is solved by the method for forming an interlayer insulating film according to any one of the eleventh invention or the twelfth invention.

【0019】

Alternatively, the fourteenth invention, which has the porous property.₂Any of the fifth invention, the sixth invention, the eleventh invention, the twelfth invention, or the thirteenth invention, which comprises forming a cover insulating film on the film and on the barrier metal layer. The solution is solved by the method for forming an interlayer insulating film described. Alternatively, the first SiO having the porosity according to the first invention, which is the fifteenth invention.₂Membrane, a third SiO having the porosity described in the second invention₂The film or SiO having the porosity according to the third to fourteenth inventions.₂After forming the film, the first SiO having the porosity₂Membrane, a third SiO with the porosity₂Membrane or SiO with the porosity₂It is solved by the method for forming an interlayer insulating film according to any one of the first to fourteenth inventions, wherein the film is treated with H (hydrogen) plasma.

【0020】

Alternatively, the problem is solved by a semiconductor device having an interlayer insulating film formed by the method for forming an interlayer insulating film according to any one of the first to fifteenth inventions, which is the sixteenth invention. Next, the operation of the present invention will be described. According to the method for forming an interlayer insulating film according to the present invention, firstly, a first SiO is placed on an object to be formed.₂Form a film. This first SiO₂The membrane is composed of TEOS and O at a concentration lower than the concentration required for oxidation of the TEOS.₃Since it is formed by using a chemical vapor deposition method in which and is contained in the reaction gas, it has a large number of voids in the membrane. That is, the first SiO₂The membrane is porous.

【0021】

Therefore, the first SiO₂The relative permittivity of the film is normal SiO without porosity.₂It is lower than the membrane. Also, the first SiO₂On the film, a second SiO₂Form a film. This second SiO₂The membrane is composed of TEOS and O at a concentration sufficient to oxidize the TEOS.₃Is formed by a chemical vapor deposition method in which and is contained in the reaction gas. Therefore, the second SiO₂The membrane is a dense SiO with no CH or OH groups in the membrane.₂It becomes a film.

【0022】

That is, a dense second SiO₂A first SiO that has porosity due to the membrane₂It is possible to prevent moisture from entering the inside of the film, and it is possible to form an interlayer insulating film having good hygroscopicity. Furthermore, the first and second SiO₂Since the film is mainly composed of Si and O, it can be expected that the heat resistance of the film will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0023】

Secondly, according to the method for forming an interlayer insulating film according to the present invention, a third SiO having porousness on the underlying insulating film after forming the underlying insulating film on the object to be formed.₂Form a film. This third SiO₂Membranes have TEOS and a concentration of O that is lower than the concentration required to oxidize TEOS.₃Is formed using a chemical vapor deposition method in which and is contained in the reaction gas. This third SiO₂Since the film is formed on the underlying insulating film, the first SiO₂It has more voids in the membrane than the membrane.

【0024】

As a result, the third SiO₂The relative permittivity of the film is the first SiO₂It is even lower than the relative permittivity of the film. Also, the third SiO₂On the film, a fourth SiO₂Form a film. This fourth SiO₂The membrane is TEOS and O at a concentration sufficient to oxidize TEOS.₃Is formed by a chemical vapor deposition method in which and is contained in the reaction gas. Therefore, the fourth SiO₂The membrane is a dense SiO with no CH or OH groups in the membrane.₂It becomes a film.

【0025】

That is, a precise fourth SiO₂A third SiO that has porosity due to the membrane₂It is possible to prevent moisture from entering the inside of the film, and it is possible to form an interlayer insulating film having good hygroscopicity. Furthermore, the third and fourth SiO₂Since the film is mainly composed of Si and O, it can be expected that the heat resistance of the film will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0026】

Third, according to the method for forming an interlayer insulating film according to the present invention, the second SiO₂Membrane or 4th SiO₂After forming the films, their surfaces are flattened by the CMP method (Chemical Mechanical Polishing Method). Then, a cover insulating film is formed on the flattened surface. As a result, an interlayer insulating film having a flat surface and good hygroscopicity and heat resistance can be formed.

【0027】

Fourth, according to the method for forming an interlayer insulating film according to the present invention, the object to be formed is treated with Cl (chlorine) plasma. As a result, Cl (chlorine) atoms remain on a part of the surface of the object to be formed. Then TEOS and O₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO is placed on the object to be formed.₂Form a film. At this time, SiO remains on the surface of the object to be formed where Cl (chlorine) atoms remain.₂Membrane growth is impeded. Therefore, this SiO₂A large number of voids are formed inside the membrane. That is, this SiO₂The membrane will have porosity.

【0028】

Therefore, SiO having this porosity₂The relative permittivity of the film is normal SiO without porosity.₂It is lower than the membrane. Furthermore, SiO having this porosity₂Since the film is mainly composed of Si and O, it can be expected that the heat resistance of the film will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0029】

Fifth, according to the method for forming an interlayer insulating film according to the present invention, Cl (chlorine) plasma treatment is performed after forming an underlying insulating film on the object to be formed. And TEOS and O₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO having porousness on the underlying insulating film₂Form a film. SiO with this porosity₂The film is formed on the underlying insulating film and has more voids in the film than when it is formed directly on the object to be formed as described above.

【0030】

Therefore, SiO having this porosity₂The film has a lower relative permittivity than when it is formed directly on the object to be formed. Sixth, according to the method for forming an interlayer insulating film according to the present invention, SiO having porosity on a Cl (chlorine) plasma-treated object to be formed.₂SiO with porosity on the membrane or on the underlying insulating film treated with Cl (chlorine) plasma₂A first insulating film is formed on the film. Then, after the first insulating film is etched and flattened, a cover insulating film is formed on the first insulating film.

【0031】

That is, the porous SiO₂It is possible to prevent moisture from entering the inside of the film, and it is possible to form an interlayer insulating film having a flat surface and good hygroscopicity and heat resistance. Seventh, according to the method for forming an interlayer insulating film according to the present invention, a SiO having the above-mentioned porosity and a low dielectric constant.₂The method of forming the membrane can be applied to the damascene process.

【0032】

That is, SiO having the above-mentioned porosity on the object to be formed.₂After forming the film, a damascene groove is formed. Then, a sidewall insulating film is formed on the side portion of the damascene groove, and a metal film is embedded inside the damascene groove. At this time, the metal film inside the damascene groove is porous due to the sidewall insulating film.₂It can be prevented from diffusing inside the membrane. Then, a barrier metal layer is formed on the metal film. This barrier metal layer can prevent the metal film from diffusing into the film formed on top of it.

【0033】

Further, after forming the underlying insulating film on the object to be formed, SiO having the above-mentioned porosity₂SiO with this porosity by forming a film₂The relative permittivity of the film can be further reduced. In the damascene process, a Cu wiring layer with low electrical resistance can be formed, so that the Cu wiring and SiO having the above-mentioned porosity can be formed.₂By using a film together, a semiconductor device with a small RC delay can be manufactured.

【0034】

Eighth, according to the method for forming an interlayer insulating film according to the present invention, after the barrier metal layer is formed, SiO having a porous property on the barrier metal layer is formed.₂A cover insulating film is formed on and on the film. That is, the porous SiO₂It is possible to prevent moisture from entering the inside of the film, and it is possible to form an interlayer insulating film having good hygroscopicity.

【0035】

Ninth, according to the method for forming an interlayer insulating film according to the present invention, SiO having the above-mentioned porosity₂After forming the film, H (hydrogen) plasma treatment is performed. As a result, the dangling bond of Si in the Si-O bond on the surface of the void is replaced with the Si-H bond, and the surface of the void can be stabilized. As a result, it is possible to prevent moisture from entering from the surface of the voids, and it is possible to form an interlayer insulating film having good hygroscopicity.

【0036】

BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described with reference to the drawings. (First Embodiment) (a) to (d) of FIG. 1 and (a) to (c) of FIG. 2 are cross-sectional views for explaining the first embodiment.

【0037】

First, as shown in FIG. 1A, a BPSG (borophosphosilicate glass) film 102 is formed on a silicon substrate 101. Then, after forming an aluminum film on the BPSG film 102, it is patterned to form an aluminum wiring layer 103. The silicon substrate 101, the BPSG film 102, and the aluminum wiring layer 103 formed in this way constitute the formed body 104.

【0038】

Next, as shown in FIG. 1 (b), SiO is placed on the formed body 104.₂A film 105 (underlayer insulating film) is formed. This SiO₂The membrane 105 is formed by a plasma CVD method (plasma chemical vapor deposition method), and SiH is used as a reaction gas.₄And N₂Use O. This SiO₂The film thickness of the film 105 is 1000 Å. Subsequently, as shown in FIG. 1 (c), SiO₂SiO with porosity on the film 105 (underlayer insulating film)₂Membrane 106 (3rd SiO₂Membrane) is formed. This SiO₂Membrane 106 is formed by atmospheric pressure CVD method (normal pressure chemical vapor deposition method), and TEOS (Tetra-Ethyl-Ortho-Silicate) and O₂(Oxygen) and low concentration of O₃Use a reaction gas containing (ozone). Here, low concentration of O₃Is a concentration of O that is lower than the concentration required for the oxidation of TEOS.₃Is to say. Specifically, the flow rate of TEOS is 25 sccm, O₂The flow rate of is 7.5 slm. And O₃Is O₂It contains 1 to 2% of the flow rate.

【0039】

The above-mentioned reaction gas includes N.₂(Nitrogen) is contained at a flow rate of 1 to 3 slm. And SiO₂While forming the film 106, the temperature of the silicon substrate 101 is maintained at 400 ° C. In general, TEOS and O₃In the normal pressure CVD method using as a reaction gas, SiO formed by it₂The following are known about membranes. That is, O in the reaction gas₃The higher the concentration of, the faster the oxidation of TEOS proceeds on the wafer, and the more fluid SiO₂A film is formed. On the contrary, O₃If the concentration of is low, TEOS is not sufficiently oxidized. Therefore, O₃When the concentration of is low, SiO formed on the wafer₂Many CH groups and OH groups remain in the membrane of the membrane. Especially, the base is SiO₂In the case of membranes, TEOS and low concentrations of O₃Due to the rough surface of SiO₂Overgrowth of the membrane occurs.

【0040】

SiO₂Membrane 106 (3rd SiO₂Membrane) is the above SiO₂It is formed by utilizing the abnormal growth of the membrane and has many voids in the membrane. Next, as shown in Fig. 1 (d), SiO with porosity₂Membrane 106 (3rd SiO₂The membrane) is subjected to H (hydrogen) plasma treatment. This H plasma treatment has a flow rate of 600 sccm.₂With (hydrogen) supplied to the chamber (not shown), RF power is applied to the upper and lower electrodes (neither shown) provided in the chamber so as to face each other. .. As the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 50 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. Further, the pressure of the chamber during this H plasma treatment is 0.1 to 0.2 Torr, and the temperature of the silicon substrate 101 is maintained at 400 ° C. The processing time of this H plasma processing is 60 seconds.

【0041】

By this H plasma treatment, the dangling bond of Si in the Si-O bond on the surface of the void is replaced with the Si-H bond. Therefore, on the surface of the void, it becomes difficult for OH groups and water to bond to the dangling bond of Si in the Si-O bond, and the moisture absorption resistance of the film is improved. Next, as shown in Fig. 2 (a), SiO with porosity₂Membrane 106 (3rd SiO₂On the membrane), SiO₂Membrane 107 (4th SiO₂Membrane) is formed. This SiO₂Membrane 107 is formed by atmospheric CVD and TEOS and O₂And O₃A reaction gas containing and is used. The flow rate of TEOS at this time is 25 sccm, and O₂The flow rate of is 7.5 slm. And O₃Is O₂It contains 5-6% of the flow rate, which is sufficient to oxidize TEOS. Therefore, from what was explained above, SiO₂Membrane 107 has fluidity. As a result, SiO₂The film 107 is formed under the SiO₂Even when the surface of the film 106 has irregularities, the surface is formed in a shape close to flat, and self-flattening is performed.

【0042】

The above SiO₂The reaction gas used to form the membrane 107 is N.₂Is included at a flow rate of 1 to 3 slm. And SiO₂While forming the film 107, the temperature of the silicon substrate 101 is maintained at 400 ° C. Then, as shown in Fig. 2 (b), SiO₂Membrane 107 (4th SiO₂Membrane) and SiO formed above the convex portion 103a of the aluminum wiring layer₂Membrane 106 (3rd SiO₂The film) is polished by the CMP method (chemical mechanical polishing method) and flattened. As a result, SiO formed on the convex portion 103a of the aluminum wiring layer₂SiO formed in the film 105 (underlayer insulating film) and the recess 103b of the aluminum wiring layer.₂The film 106 will be exposed to the surface.

【0043】

Next, as shown in FIG. 2 (c), SiO formed on the convex portion 103a of the aluminum wiring layer.₂SiO formed on the film 105 (underlayer insulating film) and in the recess 103b of the aluminum wiring layer.₂Membrane 106 (3rd SiO₂On the membrane), SiO₂A film 108 (cover insulating film) is formed. This SiO₂The film 108 is formed by a plasma CVD method. The reaction gas used at this time is SiH₄And N₂O and SiO₂The film thickness of the film 108 is 1000 Å.

【0044】

SiO formed as described above₂Membrane 105 (base insulating film), 106 (third SiO₂A low dielectric constant interlayer insulating film having good heat resistance and moisture absorption resistance was formed on the object to be formed 104 by the film) and 108 (cover insulating film). That is, SiO₂The film 106 has porosity, and its relative permittivity is 2.0 to 3.0. And this value is normal SiO₂The relative permittivity of the film is smaller than 4.0.

【0045】

In addition, SiO having porosity₂Ordinary SiO on film 106₂Since the film 108 is formed, SiO₂It is possible to prevent water from entering the inside of the film 106. And SiO having porosity₂By performing H plasma treatment on the film 106, SiO₂The moisture absorption resistance of the film 106 can be improved.

【0046】

Furthermore, SiO₂Since the films 105, 106, and 108 are mainly composed of Si and O, it is expected that the heat resistance will be improved as compared with the organic low dielectric constant film according to the conventional example. In the above, SiO is placed on the body 104 to be formed.₂A SiO that forms a film 105 (underlayer insulating film) and has porosity on it.₂Membrane 106 (3rd SiO₂Membrane) was formed. However, the present invention is not limited to this, and SiO having porousness on the object to be formed 104.₂Membrane 106 (3rd SiO₂Even if the film) is directly formed, the same actions and effects as described above can be obtained. However, in order to prevent moisture from entering the formed body 104 in the film forming process, first SiO is placed on the formed body 104.₂It is preferable to form a film 105 (underlayer insulating film). This is SiO₂This is because the film 105 makes it difficult for water to infiltrate from the surface of the object 104 toward the inside thereof.

【0047】

(Second Embodiment) FIGS. 3 (a) to (d), FIGS. 4 (a) to (d), and FIGS. 5 (a) to 5 (d) explain the second embodiment. It is a cross-sectional view for this. The second embodiment is an application of the first embodiment to the damascene process.

【0048】

First, as shown in FIG. 3A, a BPSG (borophosphosilicate glass) film 202 is formed on a silicon substrate 201, an aluminum layer is formed on the film 202, and then patterning is performed to form an aluminum wiring layer 203. These become the formed body 204. Subsequently, as shown in FIG. 3 (b), SiO having a film thickness of 1000 Å is placed on the aluminum wiring layer 203.₂A film 205 (underlayer insulating film) is formed. This SiO₂Membrane 205 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O.

【0049】

Next, as shown in Fig. 3 (c), SiO₂SiO with a film thickness of 5000 Å on the film 205 (base insulating film)₂It forms a film 206. This SiO₂Membrane 206 is formed by atmospheric CVD, TEOS and O₂And low concentration O₃A reaction gas containing and is used. Here, low concentration of O₃Is a concentration of O that is lower than the concentration required for the oxidation of TEOS.₃Is to say. Specifically, the flow rate of TEOS is 25 sccm, O₂The flow rate of is 7.5 slm. And O₃Is O₂It contains 1 to 2% of the flow rate. Thus low concentration O₃Therefore, as described in the first embodiment, SiO₂Membrane 206 will have porosity.

【0050】

The above-mentioned reaction gas includes N.₂(Nitrogen) is contained at a flow rate of 1 to 3 slm. And SiO₂While forming the film 206, the temperature of the silicon substrate 201 is maintained at 400 ° C. Subsequently, as shown in FIG. 3 (d), SiO having porosity₂The membrane 206 is subjected to H (hydrogen) plasma treatment. The processing conditions for this H plasma treatment are the same as those described in the first embodiment. That is, H with a flow rate of 600 sccm₂With (hydrogen) supplied to the chamber, RF power is applied to the upper and lower electrodes provided in the chamber so as to face each other. As the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 50 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. Further, the pressure of the chamber during this H plasma treatment is 0.1 to 0.2 Torr, and the temperature of the silicon substrate 201 is maintained at 400 ° C. The processing time of this H plasma processing is 60 seconds.

【0051】

By this H plasma treatment, the dangling bond of Si in the Si-O bond on the surface of the void is replaced with the Si-H bond. Therefore, on the surface of the void, it becomes difficult for OH groups and water to bond to the dangling bond of Si in the Si-O bond, and the moisture absorption resistance of the film is improved. Subsequently, as shown in FIG. 4 (a), SiO₂Membrane 206 and SiO₂The film 205 is opened by patterning to form a damascene groove 207. This damascene groove 207 is SiO₂It leads to the aluminum wiring layer 203 formed under the film 206.

【0052】

Next, as shown in Fig. 4 (b), SiO₂SiO on the top of the film 206 and on the sides and bottom of the damascene groove 207₂A film 208 (second insulating film) is formed. This SiO₂Membrane 208 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O. SiO formed on the side of the damascene groove 207₂The Cu that is later embedded inside the damascene groove 207 by the film 208 has a porous SiO.₂It can be prevented from diffusing into the inside of the membrane 206.

【0053】

Next, as shown in Fig. 4 (c), SiO₂The film 208 (second insulating film) is anisotropically etched. As a result, SiO formed at the bottom of the damascene groove 207₂Film 208 was removed and SiO remained unetched.₂A sidewall insulating film composed of the film 208 is formed on the side of the damascene groove 207. Subsequently, as shown in FIG. 4 (d), the inside of the damascene groove 207 and SiO₂A Cu (copper) plated film 209 is formed on the film 206. The Cu plating film 209 formed inside the damascene groove 207 is used as Cu wiring.

【0054】

Next, as shown in Fig. 5 (a), SiO₂The Cu-plated film 209 formed on the film 206 is polished and removed by the CMP method (chemical mechanical polishing method). As a result, the Cu plating film remains only inside the damascene groove 207. Subsequently, as shown in FIG. 5 (b), a TiN film 210 (barrier metal layer) for barrier metal is formed on the upper part of the damascene groove 207. As a result, the Cu inside the damascene groove 207 is later formed on the upper part of the damascene groove 207.₂It can be prevented from diffusing into the membrane of the membrane.

【0055】

Next, as shown in FIG. 5 (c), the TiN film 210 formed in the other portion is etched and removed, leaving the TiN film 210a formed in the upper part of the damascene groove 207 by patterning. Subsequently, as shown in FIG. 5 (d), SiO₂SiO on film 206 and TiN film 210a₂A film 211 (cover insulating film) is formed. This SiO₂Membrane 211 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O.

【0056】

As described above, a low dielectric constant interlayer insulating film having good heat resistance and moisture absorption resistance is formed on the object to be formed 204. That is, SiO₂The film 206 has a porous property, and its relative permittivity is 2.0 to 3.0. And this value is normal SiO₂The relative permittivity of the film is smaller than 4.0. In addition, SiO having porosity₂Ordinary SiO on film 206₂Since the film 211 (cover insulating film) is formed, SiO₂It is possible to prevent moisture from entering the inside of the film 206.

【0057】

And SiO having porosity₂By performing H plasma treatment on the film 206, SiO₂The moisture absorption resistance of the film 206 can be improved. Furthermore, SiO₂Since the films 206 and 211 are mainly composed of Si and O, they are expected to have better heat resistance than the organic low dielectric constant films according to the conventional example.

【0058】

(Third Embodiment) FIGS. 6 (a) to (d), FIGS. 7 (a) to (d), and FIG. 8 are cross-sectional views for explaining the third embodiment. .. First, as shown in FIG. 6A, a BPSG (borophosphosilicate glass) film 302 is formed on a silicon substrate 301. Then, after forming an aluminum film on the BPSG film 302, it is patterned to form an aluminum wiring layer 303. The silicon substrate 301, the BPSG film 302, and the aluminum wiring layer 303 formed in this way constitute the object to be formed 304.

【0059】

Next, as shown in FIG. 6 (b), SiO is placed on the object to be formed 304.₂A film 305 (underlayer insulating film) is formed. This SiO₂Membrane 305 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O. This SiO₂The film thickness of the film 305 is 1000 Å. Subsequently, as shown in FIG. 6 (c), SiO₂Cl (chlorine) plasma treatment is performed on the film 305 (underlayer insulating film). This Cl plasma treatment has a flow rate of 600 sccm.₂This is performed by applying RF power to the upper and lower electrodes in the chamber while (chlorine) is being supplied to the chamber. Then, as the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 100 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. The pressure in the chamber during this Cl plasma treatment is about 0.2T0rr. The processing time of Cl plasma processing is 60 seconds, and the temperature of the silicon substrate 301 is maintained at 400 ° C during processing.

【0060】

By this Cl plasma treatment, SiO₂Cl (chlorine) will remain on a part of the surface of the film 305. Next, as shown in Fig. 6 (d), Cl (chlorine) plasma-treated SiO₂SiO with a film thickness of 5000 Å on the film 305 (base insulating film)₂Form film 306. This SiO₂Membrane 306 is formed by atmospheric CVD, TEOS and O₂And O₃A reaction gas containing and is used. The flow rate of TEOS at this time is 25 sccm, and O₂The flow rate of is 7.5 slm. And O₃Is O₂It contains 4 to 6% of the flow rate. Furthermore, this reaction gas contains N₂Is contained at a flow rate of 1 to 3 slm, and SiO₂The temperature of the silicon substrate 301 while forming the film 306 is 400 ° C.

【0061】

At this time, SiO₂In the part where Cl (chlorine) remains on the surface of the film 305, SiO₂The growth of membrane 306 is impeded. As a result, SiO₂Many voids are formed inside the membrane 306, and SiO₂Membrane 306 will have porosity. Subsequently, as shown in FIG. 7 (a), SiO having porosity₂The membrane 306 is subjected to H (hydrogen) plasma treatment.

【0062】

The processing conditions for this H plasma treatment are the same as those described in the first and second embodiments. That is, H with a flow rate of 600 sccm₂With (hydrogen) supplied to the chamber, RF power is applied to the upper and lower electrodes provided in the chamber so as to face each other. As the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 50 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. Further, the pressure of the chamber during this H plasma treatment is 0.1 to 0.2 Torr, and the temperature of the silicon substrate 301 is maintained at 400 ° C. The processing time of this H plasma processing is 60 seconds.

【0063】

By this H plasma treatment, the dangling bond of Si in the Si-O bond on the surface of the void is replaced with the Si-H bond. Therefore, on the surface of the void, it becomes difficult for OH groups and water to bond to the dangling bond of Si in the Si-O bond, and the moisture absorption resistance of the film is improved. Subsequently, as shown in FIG. 7 (b), SiO having porosity₂SiO on film 306₂It forms a film 307. This SiO₂The film 307 is formed by a plasma CVD method.

【0064】

Next, as shown in Fig. 7 (c), SiO₂SiO with a film thickness of 2000 Å on film 307₂A film 308 (first insulating film) is formed. This SiO₂Membrane 308 is formed by atmospheric CVD and TEOS and O₂And O₃A reaction gas containing and is used. O used at this time₃Since the concentration in the reaction gas is higher than usual, SiO₂Membrane 308 will have fluidity. As a result, SiO₂The film 308 is a SiO formed under the film 308.₂Even when the surface of the film 307 has irregularities, the surface is formed in a shape close to flat, and self-flattening is performed.

【0065】

At this time, the previously formed SiO₂Fluid SiO due to membrane 307₂Membrane 308 has porous SiO₂It is possible to prevent the film 306 from entering the voids. Then, as shown in FIG. 7 (d), for flattening, SiO₂Membrane 307 and SiO₂Etch with film 308 (first insulating film). This etching is SiO₂This is done to the extent that the membrane 308 is not completely removed.

【0066】

Next, as shown in FIG. 8, SiO remaining unremoved by etching₂Membrane 307 and SiO₂SiO on film 308 (first insulating film)₂A film 309 (cover insulating film) is formed. This SiO₂The film 309 is formed by the plasma CVD method and has a film thickness of 1000 Å. SiO formed as described above₂Membrane 305 (base insulating film), SiO₂Membrane 306, SiO₂Membrane 307, SiO₂Membrane 308 (first insulating film) and SiO₂The film 309 (cover insulating film) forms an interlayer insulating film having a low dielectric constant with good heat resistance and moisture absorption resistance on the object to be formed 304. That is, SiO₂The film 306 has a porous property, and its relative permittivity is 2.0 to 3.0. And this value is normal SiO₂The relative permittivity of the film is smaller than 4.0.

【0067】

And SiO having porosity₂By performing H plasma treatment on the film 306, SiO₂The moisture absorption resistance of the film 306 can be improved. In addition, SiO having porosity₂Normal SiO on top of membrane 306₂Since the films 307, 308, and 309 are formed, SiO₂It is possible to prevent water from entering the inside of the membrane 306. Furthermore, SiO₂Membrane 305, SiO₂Membrane 306, SiO₂Membrane 307, SiO₂Membrane 308 and SiO₂Since the film 309 is mainly composed of Si and O, it is expected that the heat resistance will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0068】

In the above, SiO is placed on the body 304 to be formed.₂A SiO that forms a film 305 (underlayer insulating film) and has porosity on it.₂Membrane 306 was formed. However, the present invention is not limited to this, and SiO having porosity on the object to be formed 304₂Even if the film 306 is directly formed, the same actions and effects as described above can be obtained. However, in order to prevent moisture from entering the formed body 304 in the film forming process, first SiO is placed on the formed body 304.₂It is preferable to form a film 305 (underlayer insulating film). This is SiO₂This is because the film 305 makes it difficult for water to infiltrate from the surface of the object to be formed 304 toward the inside thereof.

【0069】

(Fourth Embodiment) The fourth embodiment is an application of the third embodiment to the damascene process. (A) to (d) in FIG. 9, (a) to (d) in FIG. 10, (a) to (d) in FIG. 11, and (a) to (b) in FIG. 12 are the fourth. It is sectional drawing for demonstrating embodiment.

【0070】

First, as shown in FIG. 9A, a BPSG (borophosphosilicate glass) film 402 is formed on a silicon substrate 401, an aluminum layer is formed on the film 402, and then patterning is performed to form an aluminum wiring layer 403. These become the formed body 404. Subsequently, as shown in FIG. 9 (b), SiO having a film thickness of 1000 Å is placed on the aluminum wiring layer 403.₂A film 405 (underlayer insulating film) is formed. This SiO₂Membrane 405 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O.

【0071】

Next, as shown in Fig. 9 (c), SiO₂Cl (chlorine) plasma treatment is performed on the film 405 (underlayer insulating film). This Cl plasma treatment has a flow rate of 600 sccm.₂This is performed by applying RF power to the upper and lower electrodes in the chamber while (chlorine) is being supplied to the chamber. Then, as the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 100 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. The pressure in the chamber during this Cl plasma treatment is about 0.2T0rr. The processing time of Cl plasma processing is 60 seconds, and the temperature of the silicon substrate 401 is maintained at 400 ° C during processing.

【0072】

By this Cl plasma treatment, SiO₂Cl (chlorine) will remain on a part of the surface of the film 405. Subsequently, as shown in FIG. 9 (d), Cl (chlorine) plasma-treated SiO₂SiO with a film thickness of 5000 Å on the film 405 (underlayer insulating film)₂Form film 406. This SiO₂Membrane 406 is formed by atmospheric CVD, TEOS and O₂And O₃A reaction gas containing and is used. The flow rate of TEOS at this time is 25 sccm, and O₂The flow rate of is 7.5 slm. And O₃Is O₂It contains 4 to 6% of the flow rate. Furthermore, this reaction gas contains N₂Is contained at a flow rate of 1 to 3 slm, and SiO₂The temperature of the silicon substrate 401 while forming the film 406 is 400 ° C.

【0073】

At this time, SiO₂In the part where Cl (chlorine) remains on the surface of the film 405, SiO₂The growth of membrane 406 is impeded. As a result, SiO₂Many voids are formed inside the film 406, and SiO₂Membrane 406 will have porosity. Next, as shown in Fig. 10 (a), SiO with porosity₂The membrane 406 is subjected to H (hydrogen) plasma treatment.

【0074】

The processing conditions for this H plasma treatment are the same as those described in the first to third embodiments. That is, H with a flow rate of 600 sccm₂With (hydrogen) supplied to the chamber, RF power is applied to the upper and lower electrodes provided in the chamber so as to face each other. As the RF power applied to the upper electrode, one having a frequency of 13.56 MHz and a power of 50 W is used. On the other hand, as the RF power applied to the lower electrode, one having a frequency of 400 kHz and a power of 400 W is used. Further, the pressure of the chamber during this H plasma treatment is 0.1 to 0.2 Torr, and the temperature of the silicon substrate 401 is maintained at 400 ° C. The processing time of this H plasma processing is 60 seconds.

【0075】

By this H plasma treatment, the dangling bond of Si in the Si-O bond on the void surface is replaced with the Si-H bond. Therefore, on the surface of the void, it becomes difficult for OH groups and water to bond to the dangling bond of Si in the Si-O bond, and the moisture absorption resistance of the film is improved. Next, as shown in Fig. 10 (b), SiO₂On the film 406, SiO₂It forms membrane 407. This SiO₂Membrane 407 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O. This SiO₂Membrane 407 later SiO₂The Cu of the Cu-plated film formed on the upper part of the film 407 is a porous SiO₂It can be prevented from diffusing into the inside of the membrane 406.

【0076】

Subsequently, as shown in FIG. 10 (c), SiO₂Membrane 405 (base insulating film), SiO₂Membrane 406 and SiO₂The membrane 407 is perforated by patterning to form a damascene groove 408. This damascene groove 408 is SiO₂It leads to the aluminum wiring layer 403 formed under the film 405. Next, as shown in Fig. 10 (d), SiO₂SiO on the top of the membrane 407 and on the sides and bottom of the damascene groove 408₂A film 409 (second insulating film) is formed. This SiO₂The film 409 is formed by the plasma CVD method. SiO formed on the side of the damascene groove 408₂The Cu that is later embedded inside the damascene groove 408 by the membrane 409 has a porous SiO.₂It can be prevented from diffusing into the inside of the membrane 406.

【0077】

Next, as shown in Fig. 11 (a), SiO₂The film 409 (second insulating film) is anisotropically etched. As a result, SiO₂The film 409 is removed leaving behind what was formed on the side of the damascene groove 408, and a contact hole leading to the aluminum wiring layer 403 is formed in the lower part of the damascene groove 408. Then, on the side of the damascene groove 408, SiO that remained without etching₂A sidewall insulating film composed of the film 409 is formed. Also, SiO₂Membrane 407 is not removed by this etching and has porous SiO₂Remains on membrane 406.

【0078】

Subsequently, as shown in FIG. 11 (b), the inside of the damascene groove 408 and SiO₂A Cu-plated film 410 is formed on the film 407. The Cu plating film 410 formed inside the damascene groove 408 is used as Cu wiring. Next, as shown in Fig. 11 (c), SiO₂The Cu-plated film 410 formed on the film 407 is polished and removed by the CMP method. As a result, the Cu plating film 410 remains only inside the damascene groove 408.

【0079】

Subsequently, as shown in FIG. 11 (d), a TiN film 411 (barrier metal layer) for barrier metal is formed on the upper part of the damascene groove 408. As a result, the Cu inside the damascene groove 408 is later formed on the upper part of the damascene groove 408.₂It can be prevented from diffusing into the membrane of the membrane. Next, as shown in FIG. 12A, the TiN film 411 formed in the other portion is etched and removed, leaving the TiN film 411a formed in the upper part of the damascene groove 408 by patterning.

【0080】

Subsequently, as shown in FIG. 12 (b), SiO₂SiO on film 407 and TiN film 411a₂A film 412 (cover insulating film) is formed. This SiO₂Membrane 412 is formed by plasma CVD method and SiH is used as a reaction gas.₄And N₂Use O. As described above, a low dielectric constant interlayer insulating film having good heat resistance and moisture absorption resistance is formed on the object to be formed 404. That is, SiO₂The film 406 has a porous property, and its relative permittivity is 2.0 to 3.0. And this value is normal SiO₂The relative permittivity of the film is smaller than 4.0.

【0081】

And SiO having porosity₂By performing H plasma treatment on the film 406, SiO₂The moisture absorption resistance of the film 406 can be improved. In addition, SiO having porosity₂Normal SiO on top of membrane 406₂Membrane 407 and SiO₂Since the film 412 (cover insulating film) is formed, SiO₂It is possible to prevent moisture from entering the inside of the membrane 406.

【0082】

Furthermore, SiO₂Membrane 406, SiO₂Membrane 407 and SiO₂Since the film 412 is mainly composed of Si and O, it is expected that the heat resistance will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0083】

[Effect of the invention]

As described above, in the method for forming an interlayer insulating film according to the present invention, first, TEOS and O having a concentration lower than the concentration required for oxidation of the TEOS are used.₃A chemical vapor deposition method is used in which and is contained in the reaction gas. As a result, a porous low dielectric constant SiO₂A film is formed on the object to be formed. And SiO having this porosity₂Dense SiO on the film that does not contain CH or OH groups in the film₂Form a film. This dense SiO₂SiO with porosity due to the membrane₂It is possible to prevent moisture from entering the inside of the film, and it is possible to form an interlayer insulating film having good hygroscopicity. Furthermore, SiO having this porosity₂Membrane and dense SiO₂Since the film is mainly composed of Si and O, it can be expected that the heat resistance of the film will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0084】

Secondly, after forming the underlying insulating film on the object to be formed, the SiO having the above-mentioned porosity₂By forming the film, more voids can be formed in the film, and the relative permittivity can be further lowered. Thirdly, SiO having the above-mentioned porosity₂After forming the film, the surface is flattened by the CMP method to form a cover insulating film. As a result, an interlayer insulating film having a flat surface and good hygroscopicity and heat resistance can be formed.

【0085】

Fourth, after Cl (chlorine) plasma treatment of the object to be formed, TEOS and O₃By the chemical vapor deposition method in which and is contained in the reaction gas, SiO is placed on the object to be formed.₂Form a film. This SiO₂The membrane is porous and has a low relative permittivity. Furthermore, this SiO₂Since the film is mainly composed of Si and O, it can be expected that the heat resistance of the film will be improved as compared with the organic low dielectric constant film according to the conventional example.

【0086】

Fifth, after forming an underlayer insulating film on the object to be formed and plasma-treating it, SiO having the above-mentioned porosity₂Form a film. As a result, more voids can be formed in the film, and the relative permittivity can be further lowered. Sixth, the porous SiO on the Cl (chlorine) plasma-treated object.₂SiO with porosity on the film or on the underlying insulating film treated with Cl (chlorine) plasma₂A first insulating film is formed on the film, and a cover insulating film is formed. As a result, SiO with porosity₂It is possible to prevent moisture from entering the film, and it is possible to form an interlayer insulating film having good hygroscopicity.

【0087】

Seventh, the porous SiO of the present invention₂The method of forming the membrane can be applied to the damascene process. In the damascene process, a Cu wiring layer with low electrical resistance can be formed, so that the Cu wiring and SiO having the above-mentioned porosity can be formed.₂By using a film together, it is possible to provide a semiconductor device having a small RC delay. Eighth, the porous SiO of the present invention₂When the membrane is used in the damascene process, the porous SiO of the present invention₂A cover insulating film is formed on the upper part of the film and the upper part of the barrier metal layer. As a result, SiO with porosity₂It is possible to prevent moisture from entering the film, and it is possible to form an interlayer insulating film having good hygroscopicity.

【0088】

Ninth, the porous SiO of the present invention₂After forming the film, H (hydrogen) plasma treatment is performed. This stabilizes the surface of the void and prevents moisture from entering from the surface of the void. That is, an interlayer insulating film having good hygroscopicity can be formed. As a result, a semiconductor device such as an LSI has a porous body according to the present invention.₂If a film is used, the data processing speed can be increased as compared with the conventional one. That is, SiO having porosity in the present invention₂The membrane is a conventionally used SiO₂Since the relative permittivity is lower than that of the film, it is possible to reduce the electric capacity between the wirings.

[Simple explanation of drawings]

[Figure 1]

It is sectional drawing (the 1) which shows the method of forming the interlayer insulating film which concerns on 1st Embodiment of this invention.

[Figure 2]

It is sectional drawing (the 2) which shows the method of forming the interlayer insulating film which concerns on 1st Embodiment of this invention.

[Fig. 3]

It is sectional drawing (the 1) which shows the method of forming the interlayer insulating film which concerns on 2nd Embodiment of this invention.

[Fig. 4]

It is sectional drawing (the 2) which shows the method of forming the interlayer insulating film which concerns on 2nd Embodiment of this invention.

[Fig. 5]

It is sectional drawing (the 3) which shows the method of forming the interlayer insulating film which concerns on 2nd Embodiment of this invention.

[Fig. 6]

It is sectional drawing (the 1) which shows the method of forming the interlayer insulating film which concerns on 3rd Embodiment of this invention.

[Fig. 7]

It is sectional drawing (the 2) which shows the method of forming the interlayer insulating film which concerns on 3rd Embodiment of this invention.

[Fig. 8]

It is sectional drawing (the 3) which shows the method of forming the interlayer insulating film which concerns on 3rd Embodiment of this invention.

[Fig. 9]

It is sectional drawing (the 1) which shows the method of forming the interlayer insulating film which concerns on 4th Embodiment of this invention.

[Fig. 10]

It is sectional drawing (the 2) which shows the method of forming the interlayer insulating film which concerns on 4th Embodiment of this invention.

[Fig. 11]

It is sectional drawing (the 3) which shows the forming method of the interlayer insulating film which concerns on 4th Embodiment of this invention.

[Fig. 12]

It is sectional drawing (the 4) which shows the method of forming the interlayer insulating film which concerns on 4th Embodiment of this invention.

[Explanation of symbols]

101, 201, 301, 401 Silicon Substrate, 102, 202, 302, 402 BPSG (borophosphosilicate glass) membrane, 103, 203, 303, 403 Aluminum wiring layer, 103a Convex part of aluminum wiring layer, 103b Recess in the aluminum wiring layer, 104, 204, 304, 404 Body to be formed, 105, 205, 305, 405 SiO₂Membrane (underlying insulating film), 106 Porous SiO₂Membrane (third SiO₂film), 107 SiO₂Membrane (4th SiO₂film), 108, 211, 309, 412 Cover insulating film, 206, 306, 406 Polyporous SiO₂film, 207, 408 Damishin groove, 208, 409 SiO₂Membrane (second insulating film), 209, 410 Cu plating film, 210, 411 TiN film (barrier metal layer), 210a, 411a TiN film (barrier metal layer) above the damascene groove, 307, 407 SiO₂film, 308 SiO₂Membrane (first insulating film).