JP2000294633A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which is excellent in mechanical strength, moisture resistance, adhesive strength, etc., and has a highly reliable interlayer insulation film structure and its manufacturing method, by solving a problem of xerogel possible to obtain a relative permittivity of 0.2 or less without reducing greatly the effective relative permittivity of the entire interlayer insulation film. SOLUTION: In the semiconductor device which is provided with such an interlayer insulation film including a xerogel film, the interlayer insulation film comprises a first insulation film 13 made of xerogel film, a first organic insulation film 14, and a second insulation film 15 made of xerogel film. A wiring groove 31 is formed in the second insulation film 15, and a connection hole 32 is made from the first organic insulation film 14 to the first insulation film 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device having a multi-layer wiring structure used in a device process of 0.25 μm generation or later and a method of manufacturing the same.

[0002]

2. Description of the Related Art With miniaturization of semiconductor devices, it is necessary to miniaturize wirings and reduce wiring pitches. At the same time, with the demand for lower power consumption and higher speed, it has become necessary to lower the dielectric constant of the interlayer insulating film and lower the resistance of the wiring. Especially for logic devices,
Since an increase in resistance and an increase in wiring capacitance due to fine wiring lead to a reduction in device speed, multilayer wiring using a low dielectric constant film as an interlayer insulating film is required.

The miniaturization of the wiring width and the reduction of the wiring pitch are as follows.
In addition to increasing the aspect ratio of the wiring itself, increasing the aspect ratio of the space between the wirings (vacant parts)
As a result, a burden is imposed on the technology for forming vertically elongated wiring and the technology for embedding fine wiring between layers with an interlayer insulating film.
The process is complicated, and the number of processes is increasing.

[0004] After the connection holes and the wiring grooves are simultaneously filled with an aluminum-based metal or a copper-based metal by reflow sputtering, chemical mechanical polishing (hereinafter, referred to as CMP, CMP stands for Chemical Mechanical Polishing).
In the damascene process that removes excess metal on the interlayer insulating film where the connection holes and wiring grooves are formed by the method, metal wires with a high aspect ratio can be formed by etching, There is no need to embed the film, and the number of processes can be greatly reduced. This process contributes to a reduction in the total cost as the wiring aspect ratio increases and the total number of wirings increases.

On the other hand, lowering the dielectric constant of the interlayer insulating film reduces the capacitance between wirings. However, a film having a relative dielectric constant of 2.5 or less, which is applied to a device having a rule of 0.18 μm or less, is a conventional film. A silicon oxide film used for a device has a significantly different film quality from that of a silicon oxide film, and there is a demand for a process technology corresponding to the low dielectric constant film.

[0006]

It has been noted that xerogel, which can be expected to have a relative dielectric constant of 2.0 or less, is used as the material of the interlayer insulating film. This xerogel is a generally well-known material such as a silica gel used as a desiccant. At present, it is difficult to apply this xerogel to a semiconductor device due to various requirements for reliability. That is, xerogel has bubbles in 50% to 90% of its volume, and has a problem in mechanical strength, moisture resistance, adhesion, and the like as compared with an organic polymer having a relative dielectric constant of 2.5 or more. It was difficult to ensure the reliability of the system.

In order to form an interlayer insulating film from a silicon oxide-based material such as xerogel, and to form a dual damascene structure in the interlayer insulating film, conventionally, as an intermediate layer of the interlayer insulating film, silicon oxide is used. Thus, a silicon nitride film serving as an etching mask is provided. However, since the silicon nitride film is a material having a high relative dielectric constant, the effective relative dielectric constant of the interlayer insulating film has been increased. As a result, the capacitance between wiring layers has been increased.

Further, on the organic film formed on the interlayer insulating film,
In the case of forming an etching mask in which a wiring groove pattern for forming a wiring groove is formed, and in the case of forming an etching mask in which a connection hole pattern for forming a connection hole is formed, each etching mask is formed of a resist. Then, it becomes difficult to perform a resist regenerating process without damaging the underlying organic film. That is, since the etching characteristics of the organic film and the resist are similar, when the resist film is removed during the regenerating process of the resist film, the organic film is also removed at the same time. Therefore, it has been difficult to perform a resist regenerating process of removing a resist mask that failed in patterning and forming a new resist mask again. In addition, when the above-described etching mask is formed using a silicon oxide film and a silicon nitride film, the etching mask may be simultaneously etched when the interlayer insulating film made of xerogel is etched, and may not function as an etching mask. .

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor device and a method of manufacturing the same to solve the above-mentioned problems.

The semiconductor device includes an interlayer insulating film including a xerogel film. The interlayer insulating film includes a first insulating film made of a xerogel film and a first insulating film formed on the first insulating film. An organic insulating film; a second insulating film formed on the first organic insulating film and made of xerogel; and a wiring groove formed in the second insulating film and at least a connection to the wiring groove. And a connection hole formed from the first organic insulating film to the first insulating film.

In the above semiconductor device, since the interlayer insulating film is formed of the first insulating film made of xerogel, the first organic insulating film, and the second insulating film made of xerogel, the first organic insulating film is formed. The film and the second organic insulating film reinforce the mechanical strength of the first insulating film and the second insulating film made of xerogel. In addition, the first organic insulating film prevents moisture from entering from above the first insulating film into the first organic insulating film, and prevents moisture from entering from above and below the second insulating film from the first organic insulating film.
This can be prevented by the organic insulating film and the second organic insulating film. Further, the adhesion of the second insulating film made of xerogel to the base is improved by the first organic insulating film.

Further, since the first organic insulating film is formed between the first insulating film and the second insulating film, the first organic insulating film forms a connection hole in the first insulating film. In this case, it functions as an etching mask. Since the film functioning as an etching mask is formed of an organic insulating film,
The relative dielectric constant can be reduced as compared with a conventional etching mask made of a silicon nitride film, and the effective increase in the relative dielectric constant of the entire interlayer insulating film is reduced. Therefore,
The effect of reducing the relative dielectric constant by using xerogel for the interlayer insulating film is sufficiently brought out.

The method for manufacturing a semiconductor device includes a step of forming a first insulating film made of xerogel on a base, a step of forming a first organic insulating film on the first insulating film, and a step of forming a first organic insulating film. Forming a second insulating film made of xerogel on the insulating film, forming a second organic insulating film on the second insulating film, and forming a wiring groove on the second organic insulating film in an upper layer Forming a pattern and forming an inorganic film for forming a connection hole pattern in a lower layer, and transferring the connection hole pattern to the second organic insulating film and the second insulating film by etching using the inorganic film as a mask to form an opening. Forming the upper portion of the wiring groove by etching the second organic insulating film using the inorganic film as a mask and transferring the wiring groove pattern,
Etching the first organic insulating film using the insulating film as a mask and transferring the connection hole pattern to form an upper portion of the connection hole; and forming the second organic insulating film using the second organic insulating film as a mask. Forming a wiring groove by etching and etching the first insulating film using the first organic insulating film as a mask to form a connection hole.

In the method of manufacturing a semiconductor device, a first organic insulating film is formed between the first insulating film and the second insulating film, and a connection hole is formed in the first insulating film. Since the first organic insulating film is used as an etching mask, the relative dielectric constant can be lower than that of a conventional etching mask made of a silicon nitride film. Therefore, an increase in the effective relative dielectric constant of the entire interlayer insulating film due to the etching mask is suppressed as compared with the conventional manufacturing method.

Further, when forming an inorganic film on the second organic insulating film, a wiring groove pattern and a connection hole pattern are formed by forming a wiring groove pattern in the inorganic film and then forming a connection hole pattern. In the resist process used at this time, it is possible to perform a resist regenerating process. That is, since the lower layer of the inorganic film remains and covers the underlying second organic insulating film when forming the wiring groove pattern, and when the connection hole pattern is formed, at least the lower layer of the inorganic film is formed. Since the film remains, it is possible to form a resist film serving as a mask for forming a wiring groove pattern and a connection hole pattern on the inorganic film while the second organic insulating film is covered with the inorganic film. become. Therefore, even if resist patterning fails, the resist film that failed patterning is removed and a new resist film is formed without damaging the second organic insulating film underlying the inorganic film. The resist mask can be formed again by patterning the film.

Further, since the method further includes a step of transferring the connection hole pattern by etching the second organic insulating film and the second insulating film using the inorganic film as a mask, the connection is formed up to the first organic insulating film. The hole pattern is transferred and opened.
Therefore, at the time of etching for transferring the wiring groove pattern formed in the inorganic film to the second organic insulating film, the connection hole pattern is simultaneously transferred to the first organic insulating film using the second insulating film as a mask. It becomes possible.

Using the inorganic film as a mask, the second organic insulating film is etched to transfer the wiring groove pattern to form the upper portion of the wiring groove, and the first organic insulating film is formed using the second insulating film as a mask. Using the second organic insulating film as an etching mask when forming a wiring groove in the second insulating film, since the method comprises the steps of etching and transferring the connection hole pattern to form the upper portion of the connection hole. It is also possible to use the first organic insulating film as an etching mask when forming a connection hole in the first insulating film. Thus, the first insulating film and the second insulating film can be simultaneously etched using the first organic insulating film and the second organic insulating film as an etching mask. The base of the second organic insulating film is a xerogel second insulating film,
Since the base of the first organic insulating film is a xerogel first insulating film, the second and first insulating films serve as an etching stopper in the etching of the second and first organic insulating films. The etching is stopped.

Further, the second insulating film is etched using the second organic insulating film as a mask to form a wiring groove, and the first insulating film is etched using the first organic insulating film as a mask. Since the step of forming the connection hole is provided, in this etching, the wiring groove and the connection hole are simultaneously formed. Further, since the base of the second insulating film is the first organic insulating film, the first organic insulating film serves as an etching stopper, and the etching for forming the wiring groove is performed on the first organic insulating film. Stopped at

A first organic insulating film is formed between a first insulating film made of xerogel and a second insulating film made of xerogel, and a second organic insulating film is formed on the second insulating film. Therefore, the mechanical strength of the first insulating film and the second insulating film is reinforced by the first organic insulating film and the second organic insulating film. In addition, since the first organic insulating film is formed on the first insulating film, moisture that tends to enter from above the first insulating film is prevented, and the second insulating film is formed on the first organic insulating film. Is formed, and the second organic insulating film is formed thereon, so that the first organic insulating film and the second organic insulating film prevent moisture from entering above and below the second insulating film. . Further, since the second insulating film made of xerogel is formed on the first organic insulating film, the adhesion of the second insulating film to the base is enhanced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of an embodiment relating to a semiconductor device of the present invention will be described with reference to a schematic configuration diagram of FIG.

As shown in FIG. 1, as an example, a substrate 51
A substrate 11 is used in which a semiconductor element (not shown) is formed thereon, and a wiring 53, a plug (not shown) and the like are formed in an interlayer insulating film 52 covering the semiconductor element. In addition, the base 11 is not limited to the above configuration, and may have another configuration.

On the base 11, a first insulating film 13 which is a lower layer of the interlayer insulating film 12 is formed. The first insulating film 13 is made of, for example, xerogel having a thickness of 300 nm to 800 nm. As an example, the xerogel uses Nanoporous Silica developed by Nanograss. This Nanoporous Silica is a kind of porous silica, and its use is not limited to the above Nanoporous Silica. That is, a silanol resin having a relatively high molecular weight alkyl group such as aromatic is coated on a wafer, gelled, and subjected to hydrophobization treatment with a silane coupling agent or hydrogenation treatment. Any xerogel may be used.

Incidentally, a diffusion preventing layer (not shown) is formed between the wiring 53 and the first insulating film 13 as required. This diffusion prevention layer is, for example, 20 nm to 100 nm.
The wiring 53 is formed of a silicon nitride film or a silicon carbide film having a thickness of about nm, and is particularly necessary when the wiring 53 is formed of copper or a copper alloy.

A first organic insulating film 14 is formed on the first insulating film 13. This first organic insulating film 14
Is formed, for example, of an organic polymer collectively referred to as a polyaryl ether. The polyaryl ethers include, for example, FLARE manufactured by Allied Signal, SiLK manufactured by Dow Chemical, and VE manufactured by Shoe Macker.
LOX, etc.

On the first organic insulating film 14, a second insulating film 15 to be an upper layer of the interlayer insulating film 12 is formed. The second insulating film 15 has a thickness of, for example, 300 nm to 8 nm.
It is formed of a xerogel having a thickness of 00 nm.

On the second insulating film 15, a second organic insulating film 16 is formed. This second organic insulating film 1
6 is formed of, for example, a material similar to that of the first organic insulating film.

The first and second organic insulating films 14,
16 may be formed of a fluorine resin, a BCB film, a polyimide film, an amorphous carbon film, or the like. As an example of the fluororesin, a fluorocarbon film (cyclic fluororesin, Teflon (registered trademark) (PTFE), amorphous Teflon (for example, Teflon AF (trade name) manufactured by DuPont), fluorinated aryl ether, or fluorinated polyimide is used. The amorphous Teflon is not limited to Teflon AF, but may be any one having a structure represented by the following chemical formula (1).

[0028]

Embedded image

It is also possible to use a cyclopolymerized fluorinated polymer resin [for example, Cytop (trade name)]. The cyclopolymerized fluorinated polymer resin is not limited to the above-mentioned CYTOP, but may be any resin having a structure represented by the following chemical formula (2).

[0030]

Embedded image

The fluorinated polyallyl ether resin is not limited to FLARE, but may be any resin having a structure represented by the following chemical formula (3).

[0032]

Embedded image

Then, the second organic insulating film 16
A wiring groove 31 is formed over the insulating film 15 of the first embodiment, and a connection hole 32 is formed from the first organic insulating film 14 to the first insulating film 13.
Are formed.

A barrier metal layer 33 such as tantalum nitride is formed on each inner wall of the wiring groove 31 and the connection hole 32. Further, a barrier metal layer 33 is formed in the wiring groove 31.
A wiring 34 made of metal is formed through the contact hole 32.
A plug 3 made of a metal through a barrier metal layer 33 therein
5 are formed. Naturally, the wiring 34
The plug 35 and the plug 35 are made of, for example, copper and are integrally formed.

In the above description, the configuration is such that the second organic insulating film 16 is provided. However, the configuration may be such that the second organic insulating film 16 is removed, and an etching mask may be provided on the second organic insulating film 16. Alternatively, a configuration in which an inorganic film (not shown) used as a polishing stopper may be left. In this configuration, the wiring groove 31 is formed from the inorganic film to the second insulating film 15, and the wiring 34 is formed in the wiring groove 31.

Although not shown, it is also possible to form a multi-layered wiring by forming the wiring structure having the above-described configuration in multiple layers.

In the above semiconductor device, the first insulating film 13 and the second insulating film 15 are made of xerogel, and the first organic insulating film 14 is provided between the first insulating film 13 and the second insulating film 15. Is formed, and the second organic insulating film 16 is formed on the second insulating film 15, so that the first organic insulating film 1
4. The mechanical strength of the first insulating film 13 and the second insulating film 15 made of xerogel is reinforced by the second organic insulating film 16. The first organic insulating film 14 prevents moisture from entering from above the first insulating film 13 and the first organic insulating film prevents moisture from entering from above and below the second insulating film 15. 14, it can be prevented by the second organic insulating film 16. Further, the adhesion of the second insulating film 15 made of xerogel to the base is improved by the first organic insulating film 14.

Further, the first insulating film 13 and the second insulating film 1
5 and the first organic insulating film 14 was formed between
The first organic insulating film 14 functions as an etching mask when forming the connection holes 32 in the first insulating film 13.
Since the film functioning as the etching mask is formed of the organic insulating film, the relative dielectric constant can be reduced as compared with the conventional etching mask formed of the silicon nitride film, and the entire effective thickness of the interlayer insulating film 12 can be reduced. The relative rise in relative dielectric constant is reduced. Therefore, low permittivity (relative permittivity ≒
2.0) can be sufficiently brought out to the effect of using the xerogel for the interlayer insulating film 12.

Next, an embodiment of a method of manufacturing a semiconductor device according to the present invention will be described with reference to a manufacturing process diagram of FIG.

As shown in FIG. 2A, the base 11 is
As an example, a semiconductor element (not shown) is formed on a substrate 51, and a wiring 53, a plug (not shown), and the like are formed in an interlayer insulating film 52 covering the semiconductor element. A first insulating film 13 to be a lower layer portion of the interlayer insulating film 12 is formed on such a base 11 by, for example, xerogel of 300 nm to 800 nm.
m to form a film. As an example, the xerogel was formed using Nanoporous Silica developed by Nanograss, using a spin coater developed by Nanograss.
Nanoporous Silica is a kind of porous silica,
The use of the porous silica is not limited. That is,
If a silanol resin having a relatively high molecular weight alkyl group such as aromatic is coated on the wafer, gelled, and subjected to hydrophobization treatment with a silane coupling agent or hydrogenation treatment, Any xerogel may be used.

If necessary, a diffusion preventing layer (not shown) may be provided between the wiring 53 and the first insulating film 13, for example, a silicon nitride film or a silicon carbide film having a thickness of, for example, 20 nm.
It is formed to a thickness of about 100 nm. In particular, when the wiring 53 is formed of copper or a copper alloy, the above-described diffusion preventing layer is required to prevent the diffusion of copper.

Next, a first organic insulating film 14 is formed on the first insulating film 13. The first organic insulating film 14 is made of, for example, an organic polymer generally called polyarylether. This polyaryl ether includes:
For example, FLARE manufactured by Allied Signal, SiLK manufactured by Dow Chemical, VELOX manufactured by Shoe Macker, and the like are available.

In order to form the organic polymer, for example, a precursor may be formed on the first insulating film 13 by spin coating, and then cured (fired) at 300 ° C. to 450 ° C.

Next, on the first organic insulating film 14, a second insulating film 15, which is an upper layer portion of the interlayer insulating film 12, is coated with xerogel of 300 nm to 8 nm, similarly to the first insulating film 13.
It is formed by forming a film to a thickness of 00 nm. The xerogel used here is the same as that described above, and the film formation method is also the same as the above-described film formation method.

Next, a second organic insulating film 16 is formed on the second insulating film 15 by using an organic polymer collectively referred to as polyaryl ether, for example, similarly to the above-described first organic insulating film. . In the same manner as described above, this polyaryl ether may be, for example, a fluorinated polyallyl ether-based resin [eg, FLA
RE (trade name)], SiLK manufactured by Dow Chemical Company, VELOX manufactured by Shoe Macker Company, and the like.

The first and second organic insulating films 14 and 16
Can be formed of a fluorine resin, a BCB film, a polyimide film, an amorphous carbon film, or the like. Examples of the fluororesin include fluorocarbon films (cyclic fluororesin, Teflon (PTFE), amorphous Teflon (for example, Teflon AF (trade name) manufactured by DuPont)),
Fluorinated aryl ethers or fluorinated polyimides can be used. In order to form the above-mentioned fluororesin, a precursor of the fluororesin is applied by a spin coating device, and then cured at 300 to 450 ° C. The material such as fluorinated amorphous carbon is acetylene (C
₂ H ₂ ) and a fluorocarbon gas [for example, octafluorobutene (C ₄ F ₈ )] can be formed by a plasma CVD method using a process gas. Also in this case, curing is performed at 300 ° C. to 450 ° C. after film formation. The amorphous Teflon is not limited to Teflon AF, but may be any as long as it has the structure represented by the chemical formula (1).

Further, it is also possible to use a cyclopolymerized fluorinated polymer resin [for example, Cytop (trade name)]. The cyclopolymerized fluorinated polymer resin is not limited to the above-mentioned CYTOP, but may be any resin having a structure represented by the above-mentioned chemical formula (2).

The fluorinated polyallyl ether-based resin is not limited to FLARE, but may be any resin having a structure represented by the above-mentioned chemical formula (3).

Subsequently, an inorganic film 17 is formed in two layers on the second organic insulating film 16 using different materials. For example, the first inorganic film 18 is formed of, for example, a silicon oxide film of 50 nm to 300 n.
m, and a second inorganic film 19, for example, a silicon nitride film of 50 nm to 150 nm is formed thereon.
m to form a film. Alternatively, only the silicon oxide film may be formed to a thickness of 80 nm to 500 nm, and the inorganic film 17 may be formed as a single layer.

The silicon oxide film is formed, for example, by spin coating using a commercially available inorganic SOG (SOG mainly containing silanol or SOG mainly containing polymer containing silanol) having a thickness of, for example, 30 nm to 100 nm. Formed. At this time, after spin coating, 150 ° C. to 200 ° C.
Baking for about 1 minute at 350 ° C ~ 4
Cure at 50 ° C. for about 30 minutes to 1 hour.

Note that the silicon oxide film may be formed by a plasma CVD method using a commercially available plasma CVD apparatus. As an example, dinitrogen monoxide (N ₂ O) gas is used as an oxidizing agent, and a silane-based gas [monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ) or trisilane (Si ₃ H ₈ )] is used as a silicon source. , The substrate temperature is set to 300 to 400 ° C., and the plasma power is
W, the film is formed by setting the pressure of the film formation atmosphere to about 1 kPa.

The silicon nitride film is formed by using a plasma CVD method. As the gas used at that time,
As an example, a silane-based gas (monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ) or the like) is used as a silicon source, ammonia, hydrazine, or the like is used as a nitriding agent, and oxidation is performed. As an agent, nitrous oxide (N
Using ₂ O), the carrier gas, nitrogen, helium, an inert gas such as argon is used. The film forming conditions are
As an example, the substrate temperature is set at 300 ° C to 400 ° C,
Plasma power of 350 W, pressure of deposition atmosphere of 1 kP
Set to about a.

Before forming the first inorganic film 18,
If necessary, especially when oxidation of the second organic insulating film 16 becomes a problem, a silicon nitride film, an amorphous silicon film, a silicon nitride oxide film, or a silicon oxide film containing more silicon than the stoichiometric amount is formed. Is preferred. At this time, it is desirable to form a film by a CVD method in a reducing atmosphere. The film thickness is preferably as thin as possible, for example, about 10 nm.

The inorganic film 17 may be a metal film or a metal compound film of titanium, titanium nitride, tantalum, tantalum nitride, or the like, in addition to the above-described films. The thickness is preferably, for example, 50 nm to 150 nm. As a film formation method, for example, general sputtering for forming a metal film or a metal compound film can be used.

Next, as shown in FIG. 2B, a resist film 21 is formed on the second inorganic film 19 by using a normal resist coating technique (for example, a spin coating method). Thereafter, the resist film 21 is patterned by lithography to form an opening 22 for forming a wiring groove.

Subsequently, using the resist film 21 as an etching mask, only the second inorganic film 19 is etched to form a wiring groove pattern 23 for forming a wiring groove. In this etching, only the second inorganic film 19 is selectively etched using, for example, a general magnetron type etching apparatus. As an example of the etching conditions when the second inorganic film 19 is formed of a silicon nitride film, trifluoromethane (CHF ₃ ) (5 sccm) and oxygen (O ₂ ) (5 s) are used as an etching gas.
ccm) and argon (Ar) (20 sccm), and the RF plasma is set to 600 W. When the second inorganic film 19 is formed of a metal compound film, for example, a chlorine-based etching gas such as boron chloride (BCl) or chlorine (Cl ₂ ) is used as the etching gas. After that, the resist film 21 is removed by ashing. FIG. 2B shows a state before the resist film 21 is removed.

Although not shown, when the inorganic film 17 (see (1) in FIG. 2) is formed of one layer of a silicon oxide film, the etching is stopped halfway and the silicon oxide film is A wiring groove pattern 23 for forming a wiring groove is formed in the upper layer of the inorganic film 17 while leaving a thickness of 300 nm. Also in this case, after forming the wiring groove pattern 23, the resist film 21 is removed by ashing.

Next, as shown in (3) of FIG.
The resist film 2 is formed on the inorganic film 19 and the first inorganic film 18 by using a normal resist coating technique (for example, a spin coating method).
4 is formed. After that, the resist film 24 is patterned by lithography, and an opening 25 for forming a connection hole is formed so as to be connected to the wiring groove pattern 23 on the layout.

Subsequently, using the resist film 24 as an etching mask, only the first inorganic film 18 is etched to form a connection hole pattern 26. In this etching, for example, only the first inorganic film 18 is selectively etched using a general etching apparatus. First inorganic film 1
As an example, the etching conditions when the silicon oxide film 8 is formed of a silicon oxide film include hexafluoroethane (C ₂ F ₆ ) (14 sccm), carbon monoxide (CO) (180 sccm), and argon (Ar) as an etching gas. )
(240 sccm) and RF plasma at 1.5 k
Set to W.

When the first inorganic film 18 is formed of a metal compound film, as in the case where the second inorganic film 19 is formed of a metal compound film, for example,
The etching may be performed using a chlorine-based etching gas such as boron chloride (BCl) or chlorine (Cl ₂ ).

Subsequently, the second inorganic film 18 is used as an etching mask by using a general etching apparatus.
The organic insulating film 16 is etched. As an example of the etching conditions, nitrogen (N ₂ ) is used as an etching gas.
(50 sccm) and argon (250 sccm), or hydrogen (H ₂ ) as their etching gas.
(〜100 sccm). Therefore, this etching is stopped on second insulating film 15. At this time, the resist film 24 is also etched, and the film thickness decreases.

Subsequently, using the first inorganic film 18 and the second organic insulating film 16 as an etching mask, the second insulating film 15 is etched using a general etching apparatus.
An opening 28 to which the connection hole pattern 26 has been transferred is formed.
In this etching, conditions similar to the etching conditions for the silicon oxide film are used. Therefore, while the second insulating film 15 is being etched, the exposed portion of the first inorganic film 18 is also etched.
Since the organic insulating film 16 serves as an etching mask, the opening 28 has a cross-sectional shape obtained by transferring the connection hole pattern 26. In this etching, the first organic insulating film 14 functions as an etching stopper and the first organic insulating film 1
Stopped on 4.

After that, the first inorganic film 18 is etched using the second inorganic film 19 as a mask, and the wiring groove pattern 23 is transferred to the first inorganic film 18. Further, as shown in FIG. 2D, the second organic insulating film 16 is etched, the wiring groove pattern 23 is transferred to form the upper part of the wiring groove 31, and the second insulating film 15 is used as a mask. Then, the first organic insulating film 14 is etched to transfer the opening 28 (see FIG. 2C) to form the upper portion of the connection hole 32.
This etching is performed, for example, using a general etching apparatus, using nitrogen as an etching gas, or using at least one of oxygen, ammonia, and hydrogen as nitrogen.
This is performed using a seeded gas. The resist film 24 (see FIG. 2C) is completely removed by the above etching. Therefore, there is no need to perform resist ashing.

Further, the second portion in which the upper portion of the wiring groove 31 is formed is formed.
The second insulating film 15 is etched using the organic insulating film 16 as a mask to complete the wiring groove 31, and the connection hole 3 is formed.
The first insulating film 13 is etched using the first organic insulating film 14 on which the upper portion 2 is formed as a mask to complete the connection hole 32. The etching gas used in this etching was the same as the etching condition for the silicon oxide film. In this etching, the second inorganic film 19 may be removed by etching. In addition,
FIG. 2D shows a state in which the second inorganic film 19 has been removed.

Next, wirings and plugs are formed by a damascene method. First, as shown in FIG. 3A, a barrier metal layer 33 such as tantalum nitride is formed on each inner wall of the wiring groove 31 and the connection hole 32 by sputtering or CVD. At that time, the barrier metal layer 33 is also formed on the first inorganic film 18. Next, a wiring material (metal) 36, for example, copper is deposited by sputtering, CVD, or electrolytic plating. When a metal is deposited by the electrolytic plating method, a seed layer (not shown) is formed in advance with the same kind of metal as the metal to be deposited.

Thereafter, the excess metal and the barrier metal layer 33 on the first inorganic film 18 are polished and removed by, for example, CMP, and the wiring groove 31 is formed as shown in FIG.
A wiring 34 made of a wiring material 36 is formed therein via a barrier metal layer 33 and a barrier metal layer 33 is formed in the connection hole 32.
A plug 35 made of a wiring material 36 is formed through the intermediary of the plug 35.
At this time, the first inorganic film 18 serves as a polishing stopper,
Depending on the thickness of the first inorganic film 18, the first inorganic film 18
May be completely removed. In this CMP, for example, an alumina slurry was used as the slurry.

Although not shown, the interlayer insulating film 1
By repeatedly performing the steps of forming the wiring 2 and the step of forming the wiring 34 and the plug 35, a multilayer wiring can be formed. In addition, the portion of the interlayer insulating film 52 between the wirings 53 can be formed of a xerogel film by the same process as described above.

In the above description, a semiconductor element is provided on the base 11, but a dual damascene structure can be formed by a manufacturing method as described above using a base having another structure. .

In the method of manufacturing a semiconductor device, the first organic insulating film 14 is formed between the first insulating film 13 and the second insulating film 15, and the connection hole 32 is formed in the first insulating film 13. Since the first organic insulating film 14 is used as an etching mask when forming a silicon nitride film, the relative dielectric constant can be made lower than that of a conventional etching mask made of a silicon nitride film. Therefore, an increase in the effective relative dielectric constant of the entire interlayer insulating film 12 due to the etching mask is suppressed as compared with the conventional manufacturing method. Therefore, the effect of using xerogel having a low dielectric constant (relative dielectric constant ≒ 2.0) for the interlayer insulating film 12 can be sufficiently obtained.

The inorganic film 17 is formed on the second organic insulating film 16.
By forming the wiring groove pattern 23 in the inorganic film 17 and then forming the connection hole pattern 26,
In the resist process used when forming the wiring groove pattern 23 and the connection hole pattern 26, the resist can be regenerated. That is, when the wiring groove pattern 23 is formed, since the lower layer (the first inorganic film 18) of the inorganic film 17 remains and covers the underlying second organic insulating film 16, When forming the first inorganic film 1, at least the lower layer of the inorganic film 17 (the first inorganic film 1) is formed.
8), the resist film 21 and the connection hole pattern serving as a mask for forming the wiring groove pattern 23 on the inorganic film 17 in a state where the second organic insulating film 16 is covered with the inorganic film 17 because the second organic insulating film 16 is covered with the inorganic film 17. It becomes possible to form a resist film 24 serving as a mask for forming 26. for that reason,
Even if resist patterning fails, the inorganic film 17
Removing the resist film that failed in patterning without damaging the second organic insulating film 16 that is the base of the method, forming a new resist film, patterning the resist film, and forming a resist mask again. Becomes possible.

Further, since a step of transferring the connection hole pattern 26 by etching the second organic insulating film 16 and the second insulating film 15 using the inorganic film 17 as a mask is provided, The connection hole pattern 26 is transferred to the film 14 and opened. Therefore, at the time of etching for transferring the wiring groove pattern 23 formed on the inorganic film 17 to the second organic insulating film 16, the wiring groove pattern 23 is simultaneously connected to the first organic insulating film 14 using the second insulating film 15 as a mask. Hole pattern 2
6 can be transferred.

Using the inorganic film 17 (the first inorganic film 18) as a mask, the second organic insulating film 16 is etched, and the wiring groove pattern 23 transferred to the first inorganic film 18 is further transferred to the wiring groove 31. Is formed, the first organic insulating film 14 is etched using the second insulating film 15 as a mask, and the connection hole pattern 26 transferred to the second insulating film 15 is further transferred to form the connection hole 32. And a step of forming an upper portion, the second organic insulating film 1 is used as an etching mask when forming the wiring groove 31 in the second insulating film 15.
6 can be used, and the first organic insulating film 1 can be used.
4 can be used as an etching mask when forming the connection hole 32 in the first insulating film 13. This makes it possible to simultaneously etch the first insulating film 13 and the second insulating film 15 using the first organic insulating film 14 and the second organic insulating film 16 as an etching mask.
That is, the wiring groove and the connection hole can be formed by simultaneous etching.

The base of the second organic insulating film 16 is a xerogel second insulating film 15 and the first organic insulating film 14
Is used as the first insulating film 13 of xerogel, the second and first insulating films 15 and 13 serve as an etching stopper in the etching of the second and first organic insulating films 16 and 14. Then, the etching is stopped.

Further, since the base of the second insulating film is the first organic insulating film, the first organic insulating film serves as an etching stopper, and the etching for forming the wiring groove is performed by the first organic insulating film. Stopped on the insulating film.

The first insulating film 13 made of xerogel
Since the first organic insulating film 14 is formed between the second insulating film 15 and the second insulating film 15 made of xerogel, and the second organic insulating film 16 is formed on the second insulating film 15, Membrane 13
In addition, the mechanical strength of the second insulating film 15 can be reinforced by the first organic insulating film 14 and the second organic insulating film 16. Further, since the first organic insulating film 14 is formed on the first insulating film 13, the first organic insulating film 14
Is prevented from penetrating from above the first insulating film 13, and the second insulating film 15 is formed on the first organic insulating film 14.
Is formed, and the second organic insulating film 16 is formed thereon, so that the first organic insulating film 14 and the second organic insulating film 16 are formed.
As a result, moisture that is to enter from above and below the second insulating film 15 is prevented. Further, since the second insulating film 15 made of xerogel is formed on the first organic insulating film 14,
The adhesion of the second insulating film 15 to the base is enhanced.

In the above manufacturing method, the inorganic film 17 is formed as two layers of the first inorganic film 18 and the second inorganic film 19; however, only one inorganic film may be formed. In this case, the inorganic film 17 is formed of, for example, a silicon oxide film, a wiring groove pattern 23 for forming a wiring groove is formed on the inorganic film 17, and a connection hole is formed below the inorganic film 17. Is formed.

Then, etching is performed using the inorganic film 17 as a mask in the same manner as described above. At this time, the inorganic film is anisotropically etched simultaneously with the formation of the explanatory hole pattern in the second insulating film 16, and the wiring groove pattern 23 formed on the inorganic film 17 is transferred to the lower layer of the inorganic film 17. Only the wiring groove pattern 23 is formed on the inorganic film 17. In this etching, the upper layer portion of the inorganic film 17 is etched and removed.

Next, the upper portion of the wiring groove 31 is formed in the second organic insulating film 16 using the inorganic film 17 on which the wiring groove pattern 23 is formed as a mask. The upper portion of the connection hole 32 is formed in the first organic insulating film 14 using the second insulating film 15 as a mask. After that, the wiring groove 31 and the connection hole 32 are formed in the same manner as described above.

In the above manufacturing method, the step of forming the inorganic film is performed in one step.
The number of times of film formation can be reduced, and the number of film forming steps can be reduced. Therefore, reduction in manufacturing cost and improvement in throughput can be achieved.

The various etching conditions described in the above embodiment are not limited to the above conditions, but may be any conditions as long as the etching target is selectively etched. It may be a condition.

[0081]

As described above, according to the semiconductor device of the present invention, the first insulating film made of xerogel, the first organic insulating film, the second insulating film made of xerogel, and the second organic insulating film are formed. Since the films are sequentially stacked, the mechanical strength of the first and second insulating films made of xerogel can be reinforced by the first and second organic insulating films. Also, the first organic insulating film prevents moisture from entering from above the first insulating film, and the first and second organic insulating films prevent moisture from entering from above and below the second insulating film. Can prevent moisture from being increased. Further, since the second insulating film made of xerogel is formed on the first organic insulating film, the adhesion of the second insulating film to the base is high. Therefore, the reliability of the interlayer insulating film using xerogel can be improved.

Further, since the film functioning as an etching mask between the first and second insulating films is formed of the first organic insulating film, the relative dielectric constant is reduced as compared with the conventional etching mask formed of a silicon nitride film. This makes it possible to reduce an increase in the effective relative dielectric constant of the entire interlayer insulating film. Therefore, the effect of reducing the dielectric constant by using xerogel for the interlayer insulating film is not impaired.

Therefore, since the interlayer insulating film can be formed of xerogel having a relative dielectric constant of about 2.0, the capacitance between wirings and the capacitance between wirings can be reduced, and the operation speed and the miniaturization can be improved. The performance of the semiconductor device can be improved.

According to the method of manufacturing a semiconductor device of the present invention,
Since the first organic insulating film is used as an etching mask when forming a connection hole in the first insulating film, the relative dielectric constant can be made lower than that of a conventional etching mask made of a silicon nitride film. . Therefore, an increase in the effective relative dielectric constant of the entire interlayer insulating film due to the etching mask can be suppressed as compared with the conventional manufacturing method.

In forming the inorganic film on the second organic insulating film, the wiring hole pattern is formed in the inorganic film, and then the connection hole pattern is formed. Therefore, when forming the wiring groove pattern and the connection hole pattern, In the resist process used for the second step, the underlying second organic insulating film is not exposed.
Regeneration processing of the resist can be performed. Therefore, the production yield can be improved.

The etching of the second organic insulating film and the first
And etching of the organic insulating film can be performed simultaneously,
At this time, a resist film having an etching characteristic similar to that of the organic insulating film can also be removed by etching, so that the step of removing the resist film used for forming the connection hole pattern can be omitted. Further, etching for forming a wiring groove in the second insulating film and etching for forming a connection hole in the first insulating film can be simultaneously performed. Therefore, the process can be simplified.

In the manufacturing method of the present invention, the first insulating film made of xerogel, the first organic insulating film, the second insulating film made of xerogel, and the second organic insulating film are sequentially stacked. The mechanical strength of the first and second insulating films can be reinforced by the first and second organic insulating films. First,
Moisture that tends to enter the second insulating film can be prevented by the first and second organic insulating films. Further, since the second insulating film made of xerogel is formed on the first organic insulating film, the adhesion of the second insulating film to the base can be improved.

Therefore, even if the interlayer insulating film is formed of xerogel, a semiconductor device having a highly reliable interlayer insulating film structure can be formed.

[Brief description of the drawings]

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

FIG. 2 is a manufacturing process diagram showing an embodiment relating to a method for manufacturing a semiconductor device of the present invention.

FIG. 3 is a manufacturing process diagram showing an embodiment relating to a method for manufacturing a semiconductor device of the present invention.

[Explanation of symbols]

12 interlayer insulating film, 13 first insulating film, 14 first organic insulating film, 15 second insulating film, 31 wiring groove, 32
… Connection hole

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/316 H01L 21/318 B 21/318 M 21/302 M 21/90 Q F term (Reference) 5F004 AA02 BA13 DA00 DA02 DA04 DA11 DA16 DA23 DA24 DA25 DA26 DB00 DB03 DB07 DB12 DB23 DB25 EA03 EA05 EA06 EA07 EA23 EB01 EB03 5F033 HH11 HH32 JJ01 JJ11 JJ32 KK11 MM02 MM13 MM06 NN06 Q10 RR04 RR06 RR08 RR09 RR21 RR22 RR24 SS01 SS02 SS15 SS22 TT04 XX12 XX18 XX24 5F058 AA04 AA10 AD02 AD04 AD06 AD10 AF01 AF02 AF04 BA20 BD02 BD03 BD04 BD09 BD10 BD15 BD19 BF01 BF02 BF29 BF23 BF29 BF29

Claims (9)

[Claims] 1. A semiconductor device having an interlayer insulating film including a xerogel film, wherein the interlayer insulating film includes a first insulating film made of a xerogel film, and a first organic film formed on the first insulating film. An insulating film, a second insulating film made of xerogel formed on the first organic insulating film, a wiring groove formed in the second insulating film, and at least a bottom of the wiring groove Connected to the first
A connection hole formed from the organic insulating film to the first insulating film. 2. A semiconductor device comprising a second organic insulating film provided on the second insulating film, wherein the wiring groove is formed from the second organic insulating film to the second insulating film. 2. The semiconductor device according to claim 1, wherein 3. The semiconductor according to claim 2, wherein an inorganic film is provided on the second organic insulating film, and the wiring groove is formed from the inorganic film to the second insulating film. apparatus. 4. A conductive plug formed to bury the connection hole, and a groove wiring formed to bury the wiring groove and to be connected to the plug. Item 2. The semiconductor device according to item 1. 5. A semiconductor device comprising: a conductive plug formed to bury the connection hole; and a groove wiring buried in the wiring groove and connected to the plug. Item 3. The semiconductor device according to item 2. 6. A conductive plug formed to bury the connection hole, and a groove wiring formed to bury the wiring groove and to be connected to the plug. Item 4. The semiconductor device according to item 3. 7. A step of forming a first insulating film made of xerogel on a base; a step of forming a first organic insulating film on the first insulating film; and a step of forming a first organic insulating film on the first organic insulating film. Forming a second insulating film made of xerogel on the second insulating film, forming a second organic insulating film on the second insulating film, and forming a wiring groove pattern on the second organic insulating film as an upper layer Forming an inorganic film for forming a connection hole pattern in a lower layer, and transferring the connection hole pattern to the second organic insulating film and the second insulating film by etching using the inorganic film as a mask. Forming an opening by etching the second organic insulating film using the inorganic film as a mask, transferring the wiring groove pattern to form an upper portion of the wiring groove, and forming the second insulating film. The first organic absorber using Etching the edge film and transferring the connection hole pattern to form an upper portion of the connection hole; etching the second organic insulation film using the second organic insulation film as a mask to form a wiring groove; Forming a connection hole by etching the first insulating film using the first organic insulating film as a mask. 8. In the step of providing the inorganic film, after forming the wiring groove pattern on the inorganic film,
8. The method according to claim 7, wherein the connection hole pattern is formed below the inorganic film. 9. The method according to claim 1, further comprising the step of forming a conductive plug in a state where the connection hole is buried, and forming a groove wiring connected to the plug in a state where the wiring groove is buried. 8. The method for manufacturing a semiconductor device according to item 7.