JPH10242143A - Semiconductor device, method and apparatus for manufacture thereof and method of forming insulation film of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the dielectric const. and improve the burying characteristic by forming an insulation film by the chemical vapor deposition using a mixed gas of a silane-based gas and hydrogen peroxide and a mixed gas of silane and hydrogen peroxide. SOLUTION: On an Si substrate 1 an Al wiring 2 is laid, a lower layer plasma oxide film 3 is formed on the surface of the substrate 1 and Al wiring 2, an Si oxide film 4 is formed on the film 3 by the chemical vapor deposition using a mixed gas of monomethyl silane which is a silane type gas contg. Si atoms coupled with hydrocarbon groups, silane and hydrogen peroxide water, and an upper layer plasma oxide film 5 is formed on the oxide film 4 to obtain a flat layer insulation film 6. This lowers the dielectric cost. And improves the burying characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, a method of manufacturing the same, and a method of forming an insulating film thereof, and more particularly to a method of forming an interlayer insulating film that fills between metal wirings.

[0002]

2. Description of the Related Art FIGS. 15 to 17 show typical steps of manufacturing an interlayer insulating film in a conventional semiconductor device.

[0005] In FIGS. 15 to 17, reference numerals indicate the following. 1p is a device not shown, a silicon substrate on which an insulating layer is formed, 2p is an aluminum wiring, 3p is a lower plasma oxide film, and 4p is formed by a plasma CVD method using a mixed gas of SiH ₄ and H ₂ O _2. The silicon oxide film 5p is an upper plasma oxide film, and 6p is an interlayer insulating film composed of a plasma oxide film 3p, a silicon oxide film 4p and a plasma oxide film 5p.

Next, a detailed description will be given of a manufacturing process for forming the interlayer insulating film 6p.

As shown in FIG. 15, an aluminum wiring 2p is formed on a silicon substrate 1p, and a lower plasma oxide film 3p is formed so as to cover the surfaces of the silicon substrate 1p and the aluminum wiring 2p.

Next, as shown in FIG. 16, a silicon oxide film 4p is formed by a CVD method using a mixed gas of SiH ₄ and H ₂ O ₂ . The silicon oxide film 4p entirely covers the lower plasma oxide film 3p.

Finally, as shown in FIG. 17, when the upper plasma oxide film 5p is formed so as to cover the entire silicon oxide film 4p, a semiconductor device having a flat interlayer insulating film 6p is obtained.

The silicon oxide film 4p in this case is generated by the following chemical reaction formula.

First, SiH ₄ shown below generates silanol (Si (OH) ₄ ) by an oxidation reaction of H ₂ O ₂ .

[0010]

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[0011]

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[0012]

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Next, the formed silanol undergoes a dehydration polymerization reaction by the following hydrolysis or thermal energy, thereby producing silicon oxide (SiO ₂ ).

[0014]

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When such a chemical reaction occurs on the silicon substrate 1p, a silicon oxide film is formed.

At this time, the molecular structure of the formed silicon oxide film 4p is, as shown in FIG.
It consists only of -OH bonds. Further, Si atoms are bonded via O atoms.

[0017]

Since the conventional semiconductor device is configured as described above, it has the following problems.

That is, to briefly describe the above-mentioned conventional technology, an interlayer insulating film in a semiconductor device is formed of a silicon compound, for example, silane (SiH ₄ ) and hydrogen peroxide (H).
CVD (Chemical Vapor D) using a gas mixture with ₂ O ₂ )
eposition) method to form a silicon oxide film.
This silicon oxide film can bury spaces between extremely fine lines of 0.25 μm or less. Furthermore, since it has excellent fluidity and thereby exhibits a self-planarizing action, it has been attracting attention as a next-generation interlayer insulating film planarizing method that replaces the conventionally used SOG (Spin on glass) method (NOVEL). SELF-PLANARIZING CVD OXIDE FOR INTERLAYER
DIELECTRIC APPLICATIONS "(Technical digestof IEDM'9
4 pages 117-120) and "PLANARISATION FOR SUB-MICRON DEV"
ICES UTILIZING A NEW CHEMISTRY "(Proceedings of DU
MIC conference '95, pages 94-100).

However, the relative dielectric constant of the silicon oxide film (formula 4) formed from silanol (formula 1 to formula 3) is 4.0 to 4.0.
5.0. With the recent miniaturization of devices, the problem of signal delay due to wiring due to parasitic capacitance of an interlayer insulating film has become more serious. For this reason, reducing the parasitic capacitance of an interlayer insulating film formed in a semiconductor device has become an important issue. In particular, it is the most important task to reduce the parasitic capacitance between the metal wirings having a fine metal wiring of 0.3 μm or less. For that purpose, there is a demand for an interlayer insulating film having excellent relative dielectric constant reduction, burying property and flattening characteristics.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to use a mixed gas of silane, a silane-based gas and a hydrogen peroxide solution, or a mixed gas of a silane-based gas and a hydrogen peroxide solution. Provided are a semiconductor device having excellent burying performance and self-planarization characteristics and further having a reduced relative dielectric constant by growing as a silicon oxide film by a CVD method, a method of manufacturing the same, and a method of forming an insulating film thereof. It is an object.

[0021]

According to a first aspect of the present invention, there is provided a method of forming an insulating film for a semiconductor device, comprising the steps of: mixing a silane-based gas containing silicon atoms bonded to a hydrocarbon group with a hydrogen peroxide solution; An insulating film is formed by a chemical vapor deposition method using a silane-based gas containing silicon atoms combined with silane and a mixed gas of silane and hydrogen peroxide solution.

According to a second aspect of the present invention, there is provided a method of forming an insulating film of a semiconductor device according to the first aspect, wherein the hydrocarbon group is an alkyl group.

According to a third aspect of the present invention, there is provided a method of forming an insulating film of a semiconductor device according to the second aspect, wherein the alkyl group is a methyl group, a dimethyl group or a trimethyl group. Features.

According to a fourth aspect of the present invention, there is provided a method of forming an insulating film for a semiconductor device according to the second aspect, wherein the alkyl group is an ethyl group, a diethyl group or a triethyl group. Features.

According to a fifth aspect of the present invention, there is provided a method of forming an insulating film for a semiconductor device according to the first aspect, wherein the hydrocarbon group is a vinyl group.

According to a sixth aspect of the present invention, there is provided a method for forming an insulating film on a semiconductor device according to any one of the first to fifth aspects, wherein the method for forming an insulating film on the semiconductor device comprises the steps of: Temperature range of -10 to 60 ° C., pressure range for forming the insulating film is 400 to 2000 mTorr, gas flow range of the silane is 0 to 120 sccm, silane containing silicon atoms bonded to the hydrocarbon group. The range of the gas flow rate of the system gas is more than 0 sccm and 120 sccm or less, and the range of the gas flow rate of the hydrogen peroxide solution is 0.35 to
It is characterized by 0.85 g / min.

According to a seventh aspect of the present invention, there is provided a semiconductor device, comprising: a semiconductor substrate; a multilayer metal wiring formed on the semiconductor substrate;
An interlayer insulating film formed between the multi-layered metal wirings on the semiconductor substrate, wherein the interlayer insulating film contains silicon atoms bonded to a hydrocarbon group.

The semiconductor device according to an eighth aspect of the present invention is the semiconductor device according to the seventh aspect, wherein the interlayer insulating film is an insulating film forming method for a semiconductor device according to any one of the first to sixth aspects. It is characterized by being formed by.

According to a ninth aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising: a first step of preparing a semiconductor substrate; a second step of forming a metal wiring on the semiconductor substrate; Forming an insulating film covering the semiconductor device, wherein the insulating film is formed by the method for forming an insulating film of a semiconductor device according to any one of the first to sixth inventions. .

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIGS. 1 to 3 are cross-sectional views schematically showing steps of manufacturing the semiconductor device in the first embodiment. FIG.
FIG. 3 is a diagram schematically showing a molecular structure of a silicon oxide film in the first embodiment. FIG. 5 is a graph showing the results of measurement of the relative dielectric constants of the silicon oxide film of the related art and the silicon oxide film in the first embodiment.

First, in FIG. 1, an aluminum wiring 2 (metal wiring) is arranged on a silicon substrate 1 (semiconductor substrate). On the silicon substrate 1, an element and an insulating layer (not shown) are formed. A lower plasma oxide film 3 is formed on the surfaces of silicon substrate 1 and aluminum wiring 2. This plasma oxide film 3 is formed by a plasma CVD method. At this time, the general conditions for forming the plasma oxide film 3 by the plasma CVD method include a forming temperature of 300 ° C., a pressure of 750 mTorr, a high frequency power of 500 W, and a source gas of SiH ₄ and nitrous oxide (N ₂ O).
The formation is performed using. The thickness of the plasma oxide film 3 is 1000 angstroms. In this case, the plasma oxide film 3 may be formed by plasma CVD using TEOS (Tetraethoxysilane) and oxygen as source gases at a forming temperature of 400 ° C., a pressure of 5 Torr, and a high frequency power of 500 W. .

Next, after the end of the manufacturing process shown in FIG. 1, as shown in FIG. 2, the lower plasma oxide film 3 is coated with one kind of a silane-based gas containing silicon atoms bonded to a hydrocarbon group. Certain monomethylsilane (SiH ₃ CH ₃ ), silane (S
iH ₄ ), using a mixed gas of hydrogen peroxide solution (H ₂ O ₂ )
Silicon oxide film 4 (HMO: Hydrogen peroxide and Methylsilane) by plasma CVD (chemical vapor deposition)
based CVD Oxide). Thus, the silicon oxide film 4 covers the aluminum wiring 2 so as to cover the aluminum wiring 2.
The space is completely filled.

The mixed gas of monomethylsilane, silane and hydrogen peroxide causes the following chemical reaction.

First, SiCH ₃ (OH) ₃ is produced by an oxidation reaction between SiH ₃ CH ₃ and H ₂ O ₂ shown below (Chem. 5). At the same time, Si (OH) ₄ is also produced by the chemical reaction between SiH ₄ and H ₂ O ₂ shown in the prior art (Chemical Formula 1,
2, 3).

[0036]

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Next, the formed SiCH ₃ (OH) ₃ is
The following hydrolysis or thermal energy dehydration condensation reaction produces Si (CH ₃ ) O _1.5 (Chem. 6). Si (OH) _{4 is} also hydrolyzed or dehydrated and condensed by thermal energy to produce SiO ₂ (Chem. 4).

[0038]

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The above-mentioned SiCH ₃ (OH) ₃ and Si
An HMO film 4 as shown in FIG. 2 is formed by a reaction between intermediates of (OH) ₄ or between final products of Si (CH ₃ ) O _1.5 and SiO ₂ .

The HMO film 4 is made of a conventional Si
Since it has excellent fluidity like (OH) _4, it can be embedded between extremely fine aluminum wirings.

Finally, after the end of the manufacturing process of FIG.
As shown in FIG. 7, by forming an upper plasma oxide film 5 on a silicon oxide film 4, a flat interlayer insulating film 6 can be obtained. The conditions for forming the plasma oxide film 5 are the same as those for the lower plasma oxide film 3. Even if the conditions are different, they do not affect the effects of the present invention.

On the upper layer of the plasma oxide film 5, a second-layer aluminum wiring (not shown) is formed, and a plasma oxide film, a silicon oxide film, and a plasma oxide film are formed in the same manner as in the first layer. . At this time, the space between the aluminum wirings of the second layer is completely filled with the silicon oxide film, so that the flattening can be achieved. In addition, a connection hole for connecting the lower aluminum wiring 2 to an upper aluminum wiring (not shown) is formed.
Thereafter, if necessary, third and fourth layers (not shown) and aluminum wiring are formed, and in a semiconductor device having a multilayer wiring structure, the space between the aluminum wirings is completely filled with a silicon oxide film, thereby flattening the semiconductor device. Can be planned.

Next, the above-described silicon oxide film 4 (HMO
The conditions for forming the film will be described.

As a forming method of the first embodiment, in the above-described manufacturing process of the silicon oxide film 4, an alkylsilane (SiH _x (CH ₃ ) _4-x ) gas is added to a hydrogen peroxide solution (H _2).
O ₂ ) and silane (SiH ₄ ) are added. Embodiment 1
The alkylsilane used in the above was monomethylsilane (SiH
₃ CH ₃ ), and the forming condition is that the forming temperature is -10 to 60.
(゜ C), forming pressure 400-2000 (mTorr)
r), the gas flow rate of SiH ₄ is 0 to 120 (sccm),
The gas flow rate of SiH ₃ CH ₃ is more than 0 (sccm) and 12
0 (sccm) or less, and the gas flow rate of H ₂ O ₂ is 0.35 to
It is performed at 0.85 g / min.

At this time, preferably, SiH ₄ and SiH ₃ C
The gas flow rate including H ₃ is 120 (sccm). That is, for example, when SiH ₄ is 50 (sccm), SiH ₃ CH ₃ is 70 (sccm).
When the gas flow rate of SiH ₄ is reduced, SiH ₃ C
The gas flow rate of H ₃ will increase, while the gas flow rate of SiH ₃ CH ₃ will decrease if the gas amount of SiH ₄ is increased. SiH ₄ and SiH ₃ C in this case
Under the conditions of the gas flow rate of H _{3 (} the gas flow rates of SiH ₄ and SiH ₃ CH ₃ are not 0 (sccm)), as shown in FIG. 4, the silicon oxide film has a Si—O bond and a Si—CH ₃ bond. , Si—OH bond. Note that Si atoms are bonded via O atoms so as to form a skeleton of the entire silicon oxide film molecule.

Here, the molecular structure of the silicon oxide film will be described in detail. When comparing the silicon oxide film of the first embodiment (FIG. 4) with the silicon oxide film of the prior art (FIG. 18), The Si—CH ₃ bond, which was not present in the silicon oxide film of the technique described above, exists as the molecular structure of the silicon oxide film. As a result, where the Si atoms existed in the conventional technique, the Si atoms escape, leaving microscopic spaces in the traces, and the density of the entire silicon oxide film decreases. As a result, the relative dielectric constant of the silicon oxide film according to the first embodiment decreases as the density decreases as compared with the related art.

As shown in FIG. 5, which is the result of the experiment of the first embodiment, the relative permittivity of the conventional technology and that of the first embodiment are different from those of the silicon oxide film according to the conventional technology. In contrast to 4.5, the silicon oxide film according to the first embodiment has a thickness of 3.3 to 3.4.

As described above, the dielectric constant of the silicon oxide film according to the first embodiment can be made lower than that of the conventional silicon oxide film.

As described above, the silicon oxide film according to the first embodiment of the present invention can be obtained by using a mixed gas of monomethylsilane, silane and hydrogen peroxide, or using monomethylsilane and hydrogen peroxide. Specifically, a similar effect of lowering the dielectric constant can be obtained. In addition, it enables embedding between metal wirings, and also maintains excellent self-planarization characteristics.

Although the HMO film 4 is formed on the lower plasma oxide film 3 in the first embodiment, it may be formed directly on the aluminum wiring 2 without forming the plasma oxide film 3.

(Embodiment 2) As described above, in Embodiment 1, monomethylsilane (SiH ₃ C) is used as an alkylsilane.
Although an example using a H _3), dimethylsilane (Si
H ₂ (CH ₃ ) ₂ ) and trimethylsilane (SiH (C
Be used H _{3) 3)} a similar effect.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 6 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using dimethylsilane. FIG. 7 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using trimethylsilane. FIG. 8 is a graph showing the relative dielectric constant of the silicon oxide film of the related art and the silicon oxide film of the second embodiment.

As with the HMO film 4 of the first embodiment, a semiconductor device is manufactured by the manufacturing method shown in FIGS. 1 to 3 for the silicon oxide film of the second embodiment. The only difference is that the gas used as the raw material used in Embodiment 1 is changed from monomethylsilane to dimethylsilane or trimethylsilane. Conditions (formation temperature, formation pressure, gas flow rate, etc.) for forming a silicon oxide film in the second embodiment
Are the same conditions as in the first embodiment, and the plasma CV
Generation is performed by the D method. In addition, the same applies to the case where only hydrogen peroxide and silane or hydrogen peroxide are added to dimethylsilane or trimethylsilane to cause a chemical reaction of the mixed gas to form a silicon oxide film.

Hereinafter, the chemical reaction formula of the second embodiment will be described.

The dimethylsilane used in the second embodiment is converted to Si (CH) by the following oxidation reaction.
₃ ) ₂ (OH) ₂ is produced (Chem. 7).

[0057]

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Next, the generated Si (CH ₃ ) ₂ (OH)
_{When 2} undergoes a dehydration condensation reaction, Si (CH ₃ ) ₂ O ₂ is generated (Chem. 8).

[0059]

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The silane undergoes a chemical reaction in the same manner as in the first embodiment to produce an intermediate Si (OH) ₄ and a final product SiO ₂ (Chemical Formulas 1, 2, 3, and 4). Intermediate Si (C
The silicon oxide film 4 of FIG. 3 is formed by the reaction between H ₃ ) ₂ (OH) ₂ and Si (OH) ₄ or between the final products Si (CH ₃ ) ₂ O ₂ and SiO ₂ .

On the other hand, trimethylsilane undergoes a chemical reaction of an oxidation reaction (Chem. 9) and a dehydration condensation reaction (Chem. 10) shown below, and silane also undergoes an oxidation reaction (Chem. 1, 2 and 2).
3) The silicon oxide film 4 shown in FIG. 3 is formed by the occurrence of the dehydration condensation reaction (Chem. 4).

[0062]

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[0063]

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Since the silicon oxide film 4 of FIG. 3 formed from dimethylsilane and trimethylsilane has excellent fluidity, it can be buried between extremely fine aluminum wirings.

When hydrogen peroxide and silane are added to dimethylsilane or trimethylsilane, the molecular structure of the silicon oxide film of the second embodiment is, as shown in FIGS. -OH bond and Si-CH
Consists of _three bonds. Some Si atoms have two or three CH ₃ groups bonded per Si atom. Thus, similarly to the HMO film 4 of the first embodiment (FIG. 4), the place where the Si atom was present in comparison with the related art is missing the Si atom. For this reason, a space exists at the trace that has come out, and the density of the entire silicon oxide film decreases. As a result, the HM of the first embodiment is included in the molecule of the silicon oxide film of the second embodiment.
As in the case of the O film, the density of the silicon oxide film decreases.

As described above, the density in the molecular structure of the silicon oxide film is reduced, so that the relative dielectric constant can be reduced. Further, the space between the aluminum wirings 2 can be filled with a silicon oxide film, and excellent filling characteristics can be realized. In addition, it is possible to realize excellent self-flattening characteristics.

As shown in FIG. 8, which is the result of the experiment of the second embodiment, the relative dielectric constants of the conventional silicon oxide film and the silicon oxide film of the second embodiment are different from those of the conventional technology. While the relative permittivity of the silicon oxide film is 4.5, the silicon oxide film according to the second embodiment has a relative dielectric constant of 3.3 to 3.0.
3.4.

As described above, the relative dielectric constant of the silicon oxide film according to the second embodiment can be reduced as compared with the conventional silicon oxide film.

As described above, the silicon oxide film according to the second embodiment of the present invention is made of a mixed gas of dimethylsilane or trimethylsilane and silane and hydrogen peroxide, or a mixed gas of dimethylsilane or trimethylsilane and hydrogen peroxide. The effect of lowering the dielectric constant can be obtained by using a gas. In addition, it is possible to embed between metal wirings and to maintain excellent self-planarization characteristics.

(Embodiment 3) As described above, Embodiments 1 and 2
In this example, a methyl silane was used, but monoethylsilane (SiH ₃ (C ₂ H ₅ )), diethyl silane (SiH ₂ (C ₂ H ₅ ) ₂ ), and triethyl silane (S
Similar effects can be obtained by using iH (C ₂ H ₅ ) ₃ ).

Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 9 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using monoethylsilane. FIG. 10 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using diethylsilane.
FIG. 11 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using triethylsilane. FIG.
2 is a graph showing the relative dielectric constant between the silicon oxide film of the conventional technique and the silicon oxide film of the third embodiment.

The silicon oxide film of the third embodiment is similar to the HMO film 4 of the first embodiment and the silicon oxide film 4 of the second embodiment in the manufacturing method shown in FIGS. To manufacture a semiconductor device. The difference is that methyl silane is used as a raw material, but ethyl silane is used. The conditions (formation temperature, formation pressure, gas flow rate, etc.) for forming the silicon oxide film in the third embodiment are exactly the same as those in the first and second embodiments, and are performed by the plasma CVD method. The same applies to the case where a silicon oxide film is formed by a chemical reaction of a mixed gas obtained by adding hydrogen peroxide water and silane or only hydrogen peroxide water to monoethylsilane, diethylsilane or triethylsilane.

Hereinafter, the chemical reaction formula of the third embodiment will be described.

Monoethylsilane is converted into an intermediate Si (C ₂ H ₅ ) (OH) ₃ and a final product Si by a chemical reaction of an oxidation reaction (Chem. 11) and a dehydration polymerization reaction (Chem. 12) shown below. (CH ₃ ) O _1.5 is produced.

[0076]

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[0077]

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On the other hand, silane is also subjected to a chemical reaction (Chemical formulas 1, 2, 3,
As a result of 4), an intermediate Si (OH) ₄ and a final product SiO ₂ are produced. This Si (C ₂ H ₅ ) (OH) ₃ ,
Si (OH) ₄ intermediates or Si (CH ₃ ) O
_1.5 , a silicon oxide film 4 of FIG. 3 is formed by a chemical reaction between the final products of SiO ₂ .

Diethylsilane is also produced by the following chemical reaction of oxidation reaction (Chemical formula 13), dehydration polymerization reaction (Chemical formula 14), and chemical reaction of silane (Chemical formulas 1, 2, 3, and 4). The silicon oxide film 4 of FIG. 3 is formed.

[0080]

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[0081]

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Similarly, for triethylsilane, a chemical reaction of the following oxidation reaction (Chemical formula 15), a dehydration polymerization reaction (Chemical formula 16), and a chemical reaction of silane (Chemical formulas 1, 2, 3,
By the occurrence of 4), the silicon oxide film 4 of FIG. 3 is formed.

[0083]

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[0084]

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As described above, since the silicon oxide film 4 of FIG. 3 formed from monoethylsilane, diethylsilane, and triethylsilane also has excellent fluidity, it can be embedded between extremely fine aluminum wirings. And

The molecular structure of the silicon oxide film of the third embodiment when hydrogen peroxide and silane are added to monoethylsilane, diethylsilane or triethylsilane is as follows:
As shown in FIG. 9, FIG. 10 and FIG.
Si-OH and a bond and Si-C ₂ H ₅ bond. At this time, the Si atoms are converted to the HMO film 4 of the first embodiment.
(FIG. 4) and the silicon oxide film 4 of the second embodiment (FIG. 6,
Compared with the Si atoms in FIG. 7), the proportion of the silicon atoms in the silicon oxide film molecular structure is smaller. For this reason, more microscopic spaces exist in the molecular structure, and the density of the entire silicon oxide film decreases. as a result,
The silicon oxide film 4 of the third embodiment has a lower density than the HMO film 4 of the first embodiment or the silicon oxide film 4 of the second embodiment. Of course, it can be understood that the density is lower than that of the silicon oxide film 4p (FIG. 18) of the related art, when combined with the first and second embodiments.

As shown in FIG. 12, the relative dielectric constants of the conventional silicon oxide film and the silicon oxide film of the third embodiment are different from those of the conventional silicon oxide film. The silicon oxide film according to the third embodiment is expected to have a relative dielectric constant of about 3.0, while the relative dielectric constant of the silicon oxide film according to the above-described technique is 4.5, and the relative dielectric constant is expected to be further reduced. It is.

As described above, the relative dielectric constant of the silicon oxide film according to the third embodiment is lower than that of the conventional silicon oxide film or the silicon oxide films of the first and second embodiments. It is possible to achieve a reduction.

As described above, the silicon oxide film according to the third embodiment of the present invention is made of a mixed gas of monoethylsilane, diethylsilane or triethylsilane and silane and hydrogen peroxide, or monoethylsilane, diethylsilane or triethylsilane. An effect of lowering the dielectric constant can be obtained by using a mixed gas of silane and hydrogen peroxide. In addition, it is possible to embed between metal wirings and to maintain excellent self-planarization characteristics.

(Embodiment 4) Embodiments 1 and 2
Alkyl-based silanes are used in Examples _{2 and 3} , but vinyl silane (SiH ₃ (CH = CH ₂ )) also has the effect of lowering the relative dielectric constant.

Embodiment 4 of the present invention will be described below with reference to the drawings.

FIG. 13 is a diagram schematically showing a molecular structure when a silicon oxide film is formed using vinylsilane. FIG. 14 is a graph showing the relative dielectric constant of the silicon oxide film of the related art and the silicon oxide film of the fourth embodiment.

The silicon oxide film of the fourth embodiment is the same as the HMO film 4 of the first embodiment and the second and third embodiments.
As in the case of the silicon oxide film 4 of FIG.
A semiconductor device is manufactured by the manufacturing method shown in FIG. The difference in the manufacture of the semiconductor device in this case is that in the first, second, and third embodiments, alkylsilane is used as a raw material, but is changed to vinylsilane.

In the fourth embodiment, conditions for forming the silicon oxide film (forming temperature, forming pressure, gas flow rate, etc.)
Are the same as those in the first, second and third embodiments, and the plasma CVD method is used. The same applies to the case where a silicon oxide film is formed by a chemical reaction of a mixed gas obtained by adding hydrogen peroxide and silane or only hydrogen peroxide to vinyl silane.

Hereinafter, the chemical reaction formula of Embodiment 4 will be described.

Vinyl silane is converted into an intermediate Si (CH ＝ CH ₂ ) (OH) ₃ and a final product Si () by a chemical reaction of an oxidation reaction (Chem. 17) and a dehydration polymerization reaction (Chem. 18) shown below. CH ＝ CH ₂ ) (OH) ₃ is produced.

[0097]

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[0098]

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On the other hand, silane is also chemically reacted (Chemical formulas 1, 2, 3,
When 4) occurs, an intermediate Si (OH) ₄ and a final product SiO ₂ are generated. _{Si (CH = CH 2) (} OH)
_3, the intermediate bodies of _{Si (OH) 4, Si (} CH = CH 2)
The silicon oxide film 4 in FIG. 3 is formed by a chemical reaction between the final products of (OH) ₃ and SiO ₂ .

Since the silicon oxide film 4 formed from vinylsilane has excellent fluidity, it can be buried between very fine aluminum wirings.

As shown in FIG. 13, the molecular structure of the silicon oxide film 4 according to the fourth embodiment in the case where hydrogen peroxide and silane are added to vinyl silane is as shown in FIG.
It is composed of an H bond and a Si— (CH ＝ CH ₂ ) bond. At this time, the Si atoms are converted to the HMO film 4 of the first embodiment.
(FIG. 4) and the proportion of the silicon oxide films of the second and third embodiments (FIGS. 4, 6, 7, 9, 10, and 11) in the silicon oxide film molecular structure as compared with the Si atoms. Is decreasing. For this reason, a more microscopic space exists in the molecular structure, and the density of the entire silicon oxide film decreases. As a result, the silicon oxide film of the fourth embodiment has a lower density than the HMO film of the first embodiment and the silicon oxide films of the second and third embodiments. Of course, the conventional silicon oxide film 4p (FIG. 1)
It can be understood that the density is reduced even when compared with 8).

As described above, since the density in the molecular structure of the silicon oxide film is reduced, the relative dielectric constant can be reduced. Further, the space between the aluminum wirings 2 can be filled with the silicon oxide film 4 of the fourth embodiment, and excellent self-planarization characteristics can be realized.

As shown in FIG. 14, which is an experimental result of the fourth embodiment, the relative dielectric constants of the conventional silicon oxide film and the silicon oxide film of the fourth embodiment are different from those of the conventional silicon oxide film. The relative permittivity of the oxide film is 4.5, while the relative permittivity of the silicon oxide film according to the fourth embodiment is 2.7, and the relative permittivity is further reduced.

As described above, the relative permittivity of the silicon oxide film according to the fourth embodiment is the same as that of the conventional silicon oxide film, the HMO film of the first embodiment, and the second and third embodiments.
It is possible to lower the relative dielectric constant as compared with the silicon oxide film.

As described above, the silicon oxide film according to the fourth embodiment of the present invention has a low dielectric constant using a mixed gas of vinyl silane, silane and hydrogen peroxide or a mixed gas of vinyl silane and hydrogen peroxide. The effect of conversion can be obtained. In addition, it is possible to embed between metal wirings and to maintain excellent self-planarization characteristics.

[0106]

According to the first aspect of the present invention, a silane-based gas containing a silicon atom bonded to a hydrocarbon group and a mixed gas of silane and hydrogen peroxide water or a silane gas containing a silicon atom bonded to a hydrocarbon group. Method of forming silicon oxide film with low dielectric constant, good burying characteristics and excellent self-planarization characteristics by forming insulating film by chemical vapor deposition using mixed gas of hydrogen-based gas and hydrogen peroxide solution There is an effect that can be provided.

According to the second aspect of the present invention, since the hydrocarbon group is an alkyl group, the dielectric constant is low and the filling characteristics are low even in a chemical vapor deposition method using a silane-based gas bonded to the alkyl group. And a method of forming an insulating film having excellent self-planarization characteristics can be provided.

According to the third aspect of the present invention, the alkyl group is a methyl group, a dimethyl group or a trimethyl group, so that a chemical vapor deposition using a silane-based gas combined with a methyl group, a dimethyl group or a trimethyl group is performed. The method also provides an effect of providing a method of forming an insulating film having a low dielectric constant, good burying characteristics, and excellent self-planarization characteristics.

According to the fourth aspect of the present invention, the alkyl group is an ethyl group, a diethyl group or a triethyl group, so that chemical vapor deposition using a silane-based gas combined with an ethyl group, a diethyl group or a triethyl group is performed. The method also has the effect of providing a method for forming an insulating film having a low dielectric constant, good burying characteristics, and excellent self-planarization characteristics.

According to the fifth aspect of the present invention, since the hydrocarbon group is a vinyl group, the dielectric constant is low and the filling characteristics are low even in a chemical vapor deposition method using a silane-based gas bonded to the vinyl group. And a method of forming an insulating film having good self-planarization characteristics.

According to the sixth aspect of the present invention, the temperature range for forming the insulating film is -10 to 60 ° C., the pressure range for forming the insulating film is 400 to 2000 mTorr, and the gas flow rate range for silane is 0 to 6000 mTorr. The gas flow rate of the silane-based gas containing silicon atoms bonded to a hydrocarbon group is set to 0 sccm.
By setting the gas flow rate of the hydrogen peroxide solution to a range of 0.35 to 0.85 g / min from more than 120 sccm to less than 120 sccm, an insulating film having a low dielectric constant, excellent burying characteristics, and excellent self-planarization characteristics can be obtained. There is an effect that a forming method can be provided.

According to the seventh aspect of the present invention, the semiconductor device includes the semiconductor substrate, the multilayer metal wiring formed on the semiconductor substrate, and the interlayer insulating film formed between the multilayer metal wiring on the semiconductor substrate. Since the insulating film contains silicon atoms bonded to hydrocarbon groups, a space is created in the interlayer insulating film, so that the insulating film has a low dielectric constant, excellent filling characteristics between metal wirings, and excellent self-planarizing characteristics. There is an effect that a semiconductor device having the following can be provided.

According to the eighth aspect of the present invention, by forming the interlayer insulating film by the method of forming an insulating film for a semiconductor device according to any one of the first to sixth aspects, the dielectric constant is low and the metal wiring is There is an effect that it is possible to provide a semiconductor device having an insulating film having good burying characteristics and excellent self-planarization characteristics.

According to the ninth aspect of the present invention, the first step of preparing a semiconductor substrate, the second step of forming a metal wiring on the semiconductor substrate, and the step of forming an insulating film covering the metal wiring on the semiconductor substrate are performed. A third step of forming an insulating film.
6. A semiconductor device having an insulating film having a low dielectric constant, a good burying property between metal wirings, and an excellent self-planarizing property by being formed by the method for forming an insulating film for a semiconductor device according to any one of the above items. There is an effect that a method can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a manufacturing process of an interlayer insulating film according to Embodiments 1 to 3 of the present invention.

FIG. 2 is a cross sectional view schematically showing a step of manufacturing an interlayer insulating film according to Embodiments 1 to 3 of the present invention.

FIG. 3 is a cross-sectional view schematically showing a step of manufacturing an interlayer insulating film according to Embodiments 1 to 3 of the present invention.

FIG. 4 is a diagram schematically showing a molecular structure of a silicon oxide film according to the first embodiment of the present invention.

FIG. 5 is a graph showing a measurement result of a relative dielectric constant of a silicon oxide film according to the first embodiment of the present invention and a relative dielectric constant of a conventional silicon oxide film.

FIG. 6 is a diagram schematically showing a molecular structure of a silicon oxide film according to a second embodiment of the present invention.

FIG. 7 is a diagram schematically showing a molecular structure of a silicon oxide film according to a second embodiment of the present invention.

FIG. 8 is a graph showing a measurement result of a relative dielectric constant of a silicon oxide film according to a second embodiment of the present invention and a relative dielectric constant of a conventional silicon oxide film.

FIG. 9 is a diagram schematically showing a molecular structure of a silicon oxide film according to a third embodiment of the present invention.

FIG. 10 is a diagram schematically showing a molecular structure of a silicon oxide film according to a third embodiment of the present invention.

FIG. 11 schematically shows a molecular structure of a silicon oxide film according to a third embodiment of the present invention.

FIG. 12 is a graph showing an expected value of a relative dielectric constant of a silicon oxide film according to a third embodiment of the present invention, and a measurement result of a relative dielectric constant of a silicon oxide film of a conventional technique.

FIG. 13 is a diagram schematically showing a molecular structure of a silicon oxide film according to a fourth embodiment of the present invention.

FIG. 14 is a graph showing a measurement result of a relative dielectric constant of a silicon oxide film according to a fourth embodiment of the present invention and a relative dielectric constant of a conventional silicon oxide film.

FIG. 15 is a cross-sectional view schematically showing a manufacturing process of a conventional interlayer insulating film.

FIG. 16 is a cross-sectional view schematically showing a conventional process of manufacturing an interlayer insulating film.

FIG. 17 is a cross-sectional view schematically showing a conventional process of manufacturing an interlayer insulating film.

FIG. 18 is a diagram schematically showing a molecular structure of a conventional silicon oxide film.

[Explanation of symbols]

1 silicon substrate, 2 aluminum wiring, 3,5 plasma oxide film, 4 silicon oxide film, 6 interlayer insulating film.

Claims (9)

[Claims] 1. A method for forming an insulating film for a semiconductor device, comprising: a mixed gas of a silane-based gas containing silicon atoms bonded to a hydrocarbon group and a hydrogen peroxide solution, or a silane containing silicon atoms bonded to the hydrocarbon group. An insulating film forming method for a semiconductor device, wherein an insulating film is formed by a chemical vapor deposition method using a mixed gas of a base gas, silane, and hydrogen peroxide. 2. The method according to claim 1, wherein the hydrocarbon group is an alkyl group. 3. The method according to claim 1, wherein the alkyl group is a methyl group, a dimethyl group, or a trimethyl group.
The method for forming an insulating film of a semiconductor device according to claim 2. 4. The method according to claim 1, wherein the alkyl group is an ethyl group, a diethyl group, or a triethyl group.
The method for forming an insulating film of a semiconductor device according to claim 2. 5. The method according to claim 1, wherein the hydrocarbon group is a vinyl group. 6. A temperature range for forming the insulating film is -1.
0 to 60 ° C., the pressure range for forming the insulating film is 400
2,000 mTorr, the gas flow rate range of the silane is 0-120 sccm, and the gas flow rate range of the silane-based gas containing silicon atoms bonded to the hydrocarbon group is 0 scc.
6. The insulating film according to claim 1, wherein the gas flow rate of the hydrogen peroxide solution is in the range of 0.35 to 0.85 g / min. Forming method. 7. A semiconductor substrate, comprising: a multi-layered metal wiring formed on the semiconductor substrate; and an interlayer insulating film formed between the multi-layered metal wirings on the semiconductor substrate. A semiconductor device comprising a silicon atom bonded to a hydrocarbon group. 8. The semiconductor device according to claim 7, wherein said interlayer insulating film is formed by the method for forming an insulating film of a semiconductor device according to claim 1. 9. A first step of preparing a semiconductor substrate, a second step of forming a metal wiring on the semiconductor substrate, and a third step of forming an insulating film covering the metal wiring on the semiconductor substrate. 7. A method for manufacturing a semiconductor device, comprising: forming the insulating film by the method for forming an insulating film for a semiconductor device according to claim 1.