JP2000302791A - Silicon compound, insulating film forming material and semiconductor apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful for forming an insulating film having a low dielectric constant in a semiconductor apparatus with a multi-layer wiring structure and high reliability. SOLUTION: This compound is shown by the formula [R1 to R4 are each one selected from a group consisting of H, a (substituted) alkoxy, OH and an adamantyl ring-containing group] and has a three-dimensional space in the molecular structure such as adamantyltrimethoxysilane. The compound of the formula is obtained, for example, by dissolving adamantane bromide in dibutyl ether, reacting the solution with magnesium to give adamantylmagnesium bromide (Grignard reagent) Tetraethoxysilane is dripped on previously prepared adamantylmagnesium bromide, then stirring is stopped and the prepared solution is filtered. The filtrate is subjected to a rotary evaporator to distill off dibutyl ether. The remaining filtrate is dissolved in benzene and further lyophilized to give the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicon compound, and more particularly, to a novel silicon compound which can be advantageously used as an insulating film in the manufacture of a semiconductor device. The present invention also relates to an insulating film forming material containing the silicon compound and a high-speed semiconductor device having a low dielectric constant and highly reliable insulating film formed from the silicon compound.

[0002]

2. Description of the Related Art As is well known, with an increase in the degree of integration and an increase in element density in a semiconductor device, a demand for a multilayered semiconductor element has been particularly increased, and various types of multilayer structures have been realized. . In such a semiconductor device, in order to increase the speed, it is necessary to reduce a delay in a signal propagation speed of a wiring disposed via an interlayer insulating film. Also, the signal propagation speed is determined by the wiring resistance and the parasitic capacitance generated between the wirings. In other words, in order to reduce the delay of the signal propagation speed, the wiring resistance and the parasitic capacitance between the wirings must be determined. It is known that lowering is necessary. Further, as a recent trend, the wiring width and the wiring interval are becoming narrower due to the high integration of the semiconductor device, so that the wiring resistance is increased and the parasitic capacitance between the wirings is increased. Here, the capacitance of the insulating film between the wirings can be reduced by reducing the wiring thickness and reducing the cross-sectional area. However, when the wiring thickness is reduced, the wiring resistance further increases, so that the speed of the semiconductor device is increased. Can not do it. Therefore, in order to increase the speed of the device, it is essential to use a low-resistance wiring material such as copper or an alloy thereof and to reduce the dielectric constant of the insulating film. That is, in the development of high-speed devices in the future, it is expected that the use of low-resistance wiring materials and the lowering of the dielectric constant of the insulating film will be major factors that govern the performance of the semiconductor device. This means
This can be explained as follows.

Generally, in a semiconductor device having a multilayer structure,
Wiring delay (T) is obtained by calculating wiring resistance (R) and capacitance between wirings (C).
, And can be expressed by the following equation. T∝CR In the above equation, the relationship between the inter-wiring capacitance (C) and the dielectric constant (ε _r ) of the insulating film is as follows: if the electrode area is S, the vacuum dielectric constant is ε ₀ , and the wiring interval is d. , Can be expressed by the following equation.

C = ε ₀ · ε _r · S / d Therefore, in order to reduce the wiring delay T, it is effective means to reduce the dielectric constant of the insulating film. Conventionally, various insulating film forming materials have been proposed for forming an insulating film of a multilayer wiring of a semiconductor device. However, there is no known material that provides an insulating film having a low dielectric constant of 2.4 or less. Here, one of the criteria of the dielectric constant is set to 2.4, as mentioned above, is that the wiring interval is narrow. In a conventional semiconductor device, even if the wiring interval is 1 μm or more, the influence of the wiring delay on the speed of the entire device is small. However, when the wiring interval becomes smaller than 1 μm as in recent years, the influence on the device speed becomes large. In particular, in the future, when an integrated circuit is formed with the wiring interval of 0.5 μm or less, the parasitic capacitance between the wirings will be increased. Will greatly affect device speed. Therefore, there is an urgent need to provide an insulating film having a dielectric constant of 2.4 or less, which is not realized by the conventional insulating film forming material.

The flow of development of an insulating film forming material in the field of semiconductor devices will be described. First, silicon dioxide (SiO ₂ ), silicon nitride (SiN), and phosphosilicate glass (P
Inorganic materials such as SG), polyimide, organic SOG
Such organic polymer materials have been used. However, CVD-, which has the lowest dielectric constant among the insulating films of inorganic materials,
The dielectric constant of the SiO ₂ film is at most about 4. In addition, a SiOF film recently studied as a low dielectric constant CVD film,
Although the dielectric constant is about 3.3 to 3.5, this insulating film has a high hygroscopic property, and has a problem that the dielectric constant increases during use.

On the other hand, an organic polymer film having a relatively low dielectric constant of 2.5 to 3.0 has a glass transition temperature of 200 to 3.0.
Since the temperature is as low as 350 ° C. and the coefficient of thermal expansion is large, damage to the wiring is a problem. Further, the organic SOG film has a defect that it is oxidized by oxygen plasma ashing used for removing a resist when forming a multilayer wiring pattern, and cracks are generated. Further, since the organic resin containing organic SOG has low adhesion to the wiring material of aluminum and an alloy mainly composed of aluminum or copper and an alloy mainly composed of copper, a void (wiring and insulating film) is formed near the wiring. Is formed between them, and there is a possibility that moisture may enter there and cause wiring corrosion. Further, when this void is displaced when opening a via hole for forming a multilayer wiring, This may cause a short circuit between wiring layers.

In recent years, development of a porous insulating film forming material has been advanced. There are various methods of making porous, for example,
After forming an insulating film from an organic material and an inorganic material, heat treatment (curing) is performed at a high temperature to dissociate the organic material and make the film porous. There is a method to make it. Low-density film is an indispensable technology for the next generation of low dielectric constant insulating films. Among the insulating films formed by these methods,
Some have a dielectric constant of 2.0 or less. Further, as a newer technique, a method of reacting a material having a void in a molecule with a resin material and forming an insulating film from the modified resin material is also being studied.

However, the formation of the low-density insulating film by making the film porous is based on the size (pore diameter) of the void formed in the film.
Therefore, it is easy to absorb moisture, which may cause an increase in dielectric constant and corrosion of wiring. Further, a porous insulating film generally has poor mechanical strength, and thus is liable to be damaged particularly during chemical mechanical polishing (CMP). Furthermore, in the method of forming an insulating film using a material having a void in a molecule, the amount of voids introduced into the insulating film is limited by the resin material used in combination, so that a reduction in density is intended. Therefore, there is a limit in reducing the density.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a highly reliable insulating film having a low dielectric constant of 2.4 or less. Another object of the present invention is to provide a novel compound. Another object of the present invention is to provide a material capable of forming a low dielectric constant and highly reliable insulating film useful for a semiconductor device having a multilayer wiring structure.

It is still another object of the present invention to provide a highly reliable semiconductor device provided with an insulating film having a low dielectric constant. The above and other objects of the present invention can be easily understood from the following detailed description.

[0011]

According to one aspect of the present invention, there is provided a silicon compound having a three-dimensional void in a molecular structure, which is represented by the following formula (1):

[0012]

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(In the above formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different from each other and each represents a hydrogen atom, a substituted or unsubstituted alkoxy group, a hydroxyl group and an adamantyl ring-containing group. Represents a member selected from the group consisting of, provided that _{one to three} members of the substituents R ₁ , R ₂ , R ₃ and R ₄ are adamantyl ring-containing groups, and R ₁ , R ₂ , R ₃ And R ₄
When three members of the above are adamantyl ring-containing groups, the remaining one is an alkoxy group or a hydroxyl group).

According to another aspect of the present invention, there is provided an insulating film forming material comprising at least one kind of a silicon compound represented by the above formula (1). Further, in another aspect, the present invention resides in a semiconductor device having at least one kind of insulating film formed of a silicon compound represented by the above formula (1).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The silicon compound according to the present invention comprises
As described above, this is characterized by being represented by the above formula (1), and has three-dimensional voids in the molecular structure due to its structure. Silicon compound characterized by having a three-dimensional void in the molecular structure according to the present invention,
The state of the voids is hardly changed by reaction and bonding with other compounds. Therefore, when this silicon compound is used for forming a porous insulating film, constant voids can be secured, and thus, the obtained voids can be obtained. An extremely low dielectric constant of 2.4 or less and high reliability can be imparted to the insulating film.

In the above formula (1), R ₁ , R ₂ , R ₃ and R ₄ in the formula may be the same or different from each other, and are each a hydrogen atom, a substituted or unsubstituted alkoxy group,
For example, it represents a member selected from the group consisting of a hydroxyl group and an adamantyl ring-containing group such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group. However, in this silicon compound, _one of the substituents R ₁ , R ₂ , R ₃ and R ₄ in the above formula is used.
The two-membered or three-membered members need to be adamantyl ring-containing groups. The adamantyl ring-containing group is preferably R ₁
Can only be two members of R ₁ and R ₄ , or three members of R ₁ , R ₂ and R ₃ . When three members of the substituents R ₁ , R ₂ , R ₃ and R ₄ are adamantyl ring-containing groups, the remaining one is an alkoxy group or a hydroxyl group.

The adamantyl ring-containing group contained in the silicon compound can be preferably represented by the following formula (2).

[0018]

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In the above formula (2), Z represents a group of atoms necessary for completing an adamantyl ring together with the carbon atoms in the formula, and L represents an optional bonding group. The linking group L is
It should be arbitrarily included in the silicon compound depending on desired properties and the like, and may or may not be present. Examples of suitable linking groups L include, but are not limited to, those listed below.
For example, methylene group, alkylene group such as ethylene group, phenylene group, aromatic group such as phenoxy group, carbonyl group,
An oxo group and the like can be mentioned. In addition, it is preferable that the length of the bonding group L is relatively short in consideration of a decrease in heat resistance and the like.

The adamantyl ring-containing group as described above is
The adamantyl ring may be further substituted at any position as long as it is useful for providing a steric void in the molecular structure of the silicon compound. A suitable substituent is, for example, a lower alkyl group such as a methyl group. Further, the bonding of the adamantyl ring-containing group to the silicon atom (Si) of the silicon compound can be performed at any position of the adamantyl ring as long as the effect of the present invention is not adversely affected.

The adamantyl ring-containing group particularly useful in the practice of the present invention is, for example, the following formula (3):
It is a group represented by (4) or (5).

[0022]

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According to the findings of the present inventors, when the bonding group L is a phenylene group or a phenoxy group, excellent heat resistance can be imparted to the obtained insulating film. The silicon compound of the present invention preferably has a silicon-containing component -Si-R (wherein R represents a hydrogen atom or a substituted or unsubstituted alkyl group such as a methyl group or an ethyl group) in its molecular structure. ). That is, by introducing the water-repellent silicon-containing component -Si-R into a part of the silicon compound, the moisture resistance of the insulating film having a low dielectric constant can be further improved. Further, as described below, when there is no room for introducing such a silicon-containing component in the molecular structure of the silicon compound, that is, for example, the substituents R ₁ , R ₂ , R ₃ and R ₄
When three members of are adamantyl ring-containing groups,
A silicon compound containing a silicon-containing component -Si-R may be additionally included in the insulating film forming material. Suitable silicon compounds include, for example, silanes and silazanes.

Typical examples of the silicon compound according to the present invention include, but are not limited to, adamantyltrimethoxysilane, adamantyltriethoxysilane, adamantylphenyltriethoxysilane, adamantylphenoxytriethyl. Ethoxysilane, diadamantanediethoxysilane and the like can be mentioned. These and other silicon compounds of the present invention, although employed in the examples below, can be readily prepared using techniques well known in silicon chemistry and, therefore, The detailed description in will be omitted.

The present invention also resides in a material for forming an insulating film, which comprises a silicon compound represented by the above formula (1). The silicon compound of the present invention may be used alone or in combination of two or more of the silicon compounds of the present invention. Furthermore, if appropriate, the silicon compound of the present invention may be used. In combination with the above, a known silicon compound may be used as an insulating film forming material.

The insulating film-forming material of the present invention preferably comprises an additional silicon compound Si-R (R in the formula represents a hydrogen atom or a substituted or unsubstituted alkyl group such as a methyl group, an ethyl group. And the like) can be used in a mixed form. Suitable silicon compounds include, for example, silanes and silazanes. Such silicon compounds may additionally include or otherwise include such compounds in view of the fact that the formation of the insulating film in the present invention can be advantageously performed using a sol-gel method. It can be used as a metal alkoxide containing the corresponding silicon-containing component -Si-R in the molecule. Thus, the moisture resistance of the obtained insulating film can be further improved.

The insulating film forming material of the present invention is preferably prepared by dissolving in a suitable solvent and then forming an insulating film forming portion on the substrate, for example, a wiring pattern, by a coating method such as a spin coating method. It can be applied on a substrate. Therefore, even if there is a portion such as a narrow gap which is difficult to apply in a portion where an insulating film is formed in a semiconductor device, it can be easily and uniformly applied, which can contribute to improvement of characteristics of the obtained insulating film.

In connection with the above, the present inventors have found that the insulating film forming material of the present invention can be used for forming an insulating film by using various techniques commonly used in the field of semiconductor devices. It has been found that the sol-gel method can be used particularly advantageously when forming an interlayer insulating film or other insulating films. For example, an adamantyl ring-containing silicon compound and a metal alkoxide of the present invention,
For example, tetraethoxysilane (TEOS) is reacted in an organic solvent to produce an adamantyl-metal alkoxide. Next, an acidic aqueous solution is added to the obtained product, and an insulating film is formed by a sol-gel method. In the insulating film formed in this manner, since the space (void) formed in the film after the film formation is a minute space at the molecular level, even if the insulating film is left in the air, This space does not exhibit moisture absorption, and therefore, it is possible to form an insulating film having better moisture resistance than a conventional porous insulating film. In addition, when compared with the conventional sol-gel method silicon film, due to the effect of the minute space in the molecule,
An insulating film having a lower dielectric constant can be formed.

The sol-gel method which can be advantageously used for forming an insulating film in the present invention is a technique which is well known particularly in the field of ceramics. Appropriate methods and conditions can be arbitrarily selected and carried out. For example, as the organic solvent, acetone, tetrahydrofuran, chloroform, 2-methoxyethanol, dimethyl sulfoxide,
It is desirable to use dimethylformamide, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, and the like. In particular, acetone is suitable for the sol-gel method because it has high solubility and can be obtained at low cost. Further, as the acidic aqueous solution, an aqueous solution of an acid such as nitric acid, hydrochloric acid, and sulfuric acid can be used. The acid concentration of such an acidic aqueous solution is preferably in the range of 50 to 2000 ppm. This is because if the acid concentration is less than 50 ppm, the reaction does not proceed, and if it exceeds 2000 ppm, gelation occurs due to abrupt reaction. Therefore, it is usually most suitable to use an acidic aqueous solution at an acid concentration of about 200 to 400 ppm for the progress of the reaction. The reaction is carried out with stirring while dropping an acidic aqueous solution, and the temperature at that time is usually desirably in the range of room temperature (about 20 ° C) to 80 ° C. The drop rate of the acidic aqueous solution is
It is desirable to be in the range of 0.1 to 1.0 ml / sec. When the reaction temperature exceeds 80 ° C., the reaction rate is too fast, and the gelation is likely to occur. For example, if the acid concentration is 20
At 0 ppm, the reactivity can be improved by applying a reaction temperature of 60 ° C.

Further, the present invention resides in a semiconductor device having an insulating film formed from an insulating film forming material containing the silicon compound represented by the above formula (1) alone or in combination. The semiconductor device of the present invention is preferably a semiconductor device having a multilayer wiring structure. Therefore, the interlayer insulating film between the wirings is made of the insulating film forming material of the present invention. In the semiconductor device of the present invention, the speed can be increased by lowering the dielectric constant of the insulating film, and the increase in the dielectric constant due to moisture absorption is suppressed, so that the reliability is also improved.

On the insulating film formed according to the present invention, another insulating film such as a silicon oxide film may be formed by using, for example, a vapor growth method. This is because the insulating film formed according to the present invention is effective in shutting off the outside air and suppressing a decrease in hydrogen and fluorine remaining in the film. This other insulating film is also effective in preventing the insulating film according to the present invention from being damaged in a subsequent process (for example, a process such as planarization by CMP).

[0032]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited by the following examples. Preparation Example 1 Preparation of adamantyltriethoxysilane 1 mol of adamantane bromide was dissolved in dibutyl ether, and the resulting solution was added dropwise to a flask containing 1 mol of magnesium. When the contents of the flask were reacted with stirring, adamantyl magnesium bromide (Grignard reagent) was obtained. After 1 mol of tetraethoxysilane (TEOS) was added dropwise to the adamantyl magnesium bromide prepared above, stirring was stopped, and the resulting solution was filtered. After the filtrate was passed through a rotary evaporator to remove dibutyl ether, the remaining filtrate was dissolved in benzene and freeze-dried. The desired adamantyl triethoxysilane was obtained. Preparation Example 2 Preparation of diadamantanediethoxysilane After 2 mol of adamantane bromide was dissolved in dibutyl ether, the resulting solution was dropped into a flask containing 2 mol of magnesium. When the contents of the flask were reacted with stirring, adamantyl magnesium bromide (Grignard reagent) was obtained. After 1 mol of tetraethoxysilane (TEOS) was added dropwise to the adamantyl magnesium bromide prepared above, stirring was stopped, and the resulting solution was filtered. After the filtrate was passed through a rotary evaporator to remove dibutyl ether, the remaining filtrate was dissolved in benzene and freeze-dried. The desired diadamantanediethoxysilane was obtained. Example 1 Preparation of Insulating Film and Measurement of Dielectric Constant In a flask equipped with a stirrer, a thermometer, and a dropping funnel, 0.5 mol of adamantyltriethoxysilane prepared in Preparation Example 1 was dissolved in acetone to 20% by weight. Was prepared. 1.5M nitric acid aqueous solution (concentration 200ppm)
Was dropped into the flask, and the inside of the reaction system was heated to 60 ° C. and stirred for 2 hours. After the solution in the flask was cooled to room temperature, stirring was stopped, and filtration was further performed.

The coating solution containing adamantyltriethoxysilane prepared as described above was spin-coated on a silicon substrate at a thickness of 5000 ° C.
Drying was performed at 00 ° C. for 3 minutes to remove the solvent. Next, the dried silicon substrate was transferred to a vacuum drying furnace and heat-treated at 400 ° C. for 30 minutes in nitrogen having an oxygen concentration of 10 ppm or less. The desired insulating film was obtained.

Subsequently, a gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz. As a result, it was found to be 2.3. Further, in order to evaluate the change with time of the dielectric constant, the insulating film was left for one week in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60%, and the dielectric constant was measured in the course of the standing.
The result was plotted in FIG. 1 attached as a relationship between the standing time (days) and the dielectric constant. The dielectric constant after standing for one week was 2.5. Example 2 Fabrication of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
Adamantyl phenyl triethoxy silane prepared in the same manner as in Preparation Example 1 was used instead of adamantyl triethoxy silane. Diameter of 1 on insulating film formed
A gold (Au) electrode having a thickness of 2 mm was mask-deposited, and the dielectric constant was measured at 1 MHz. Further, in order to evaluate the change with time of the dielectric constant, the insulating film was left for one week in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60%, and the dielectric constant was measured during the process. The result was plotted as a relationship between the standing time (days) and the dielectric constant. The dielectric constant after standing for one week was 2.5. Example 3 Fabrication of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
Adamantyl phenoxy triethoxy silane prepared in the same manner as in Preparation Example 1 was used instead of adamantyl triethoxy silane. A gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz. As a result, it was found to be 2.2. Further, in order to evaluate the change with time of the dielectric constant, the insulating film was left for one week in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60%, and the dielectric constant was measured in the course of the standing.
The result was plotted in FIG. 3 attached as the relationship between the standing time (days) and the dielectric constant. The dielectric constant after standing for one week was 2.3. Example 4 Fabrication of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
Instead of adamantyltriethoxysilane, diadamantanediethoxysilane prepared in Preparation Example 2 was used. A gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz.
It turned out to be 2.2. Further, in order to evaluate the change with time of the dielectric constant, a temperature of 24 ° C. and a relative humidity (RH) of 6
The insulating film was left for one week in the atmosphere of 0%, and the dielectric constant was measured in the middle. As a result, a result was plotted in FIG. 4 as a relation between the standing time (day) and the dielectric constant. . The dielectric constant after standing for one week is 2.
It was 5. Example 5 Preparation of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
Instead of adamantyl triethoxysilane, a solution in which adamantyl triethoxysilane and diadamantandiethoxysilane prepared in Preparation Example 2 were mixed at a ratio of 1: 2 (weight ratio) was used. A gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz. As a result, it was found to be 2.2. further,
In order to evaluate the change with time of the dielectric constant, the insulating film was left for one week in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60%, and the dielectric constant was measured. Example 6 Fabrication of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
Instead of adamantyltriethoxysilane, a solution in which adamantyltriethoxysilane and methyltriethoxysilane were mixed at a ratio of 4: 1 (weight ratio) was used. A gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz. As a result, it was found to be 2.4. Furthermore, in order to evaluate the change with time of the dielectric constant, the insulating film was left in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60% for one week, and the dielectric constant was measured again to be 2.6. . Comparative Example 1 Fabrication of Insulating Film and Measurement of Dielectric Constant The method described in Example 1 was repeated.
For comparison, a solution in which tetraethoxysilane and methyltriethoxysilane were mixed at a ratio of 1: 1 (weight ratio) was used instead of adamantyltriethoxysilane. A gold (Au) electrode having a diameter of 1 mm was mask-deposited on the formed insulating film, and the dielectric constant was measured at 1 MHz. As a result, it was found to be 3.1. Further, in order to evaluate the change with time of the dielectric constant, the insulating film was left in the air at a temperature of 24 ° C. and a relative humidity (RH) of 60% for one week, and the dielectric constant was measured in the middle. The result was plotted as a relationship between the standing time (days) and the dielectric constant.
The dielectric constant after standing for one week was 3.4. Example 7 Fabrication of Semiconductor Device In this example, a semiconductor device having a multilayer wiring structure schematically shown in FIG. 6 was fabricated by the following procedure.

An active region was defined by forming a field oxide film 2 made of SiO _{2 on} the surface of a silicon substrate 1. A MOS transistor 3 including a source region 3S and a drain region 3D was further formed inside the active region. Next, the interlayer insulating film 4 of the present invention is formed to a thickness of 1.5 according to the method described in the first embodiment so as to cover the MOS transistor 3.
μm, and the surface is chemically and mechanically polished (CM
P) for flattening.

After the formation of the interlayer insulating film 4, an etching stop layer 6 made of boron nitride (BN) was deposited on the surface to a thickness of 0.1 μm by the CVD method. Next, the source region 3S
Via holes were formed by RIE in the regions corresponding to the drain region 3D and the etching stop layer 6 and the interlayer insulating film 4, respectively. Further, conductive plugs 5S and 5D were embedded in the respective via holes. As shown in the figure, the conductive plugs 5S and 5D are buried by depositing a titanium nitride (TiN) film on the inner surface of each via hole by DC magnetron sputtering, and further depositing a tungsten (W) film thereon. Thermal CVD
W film and Ti deposited in a region other than the via hole by the method
This was performed by removing the N film by CMP. After the filling of the conductive plug is completed, the etching stopper layer 6 is formed.
An etching stop layer 7 made of BN was deposited under the same film forming conditions as the etching stop layer 6. Further, on the deposited etching stopper layer 7, an interlayer insulating film 8 of the present invention was deposited to a thickness of 0.6 μm according to the method described in the first embodiment.

Subsequently, the two layers of the interlayer insulating film 8 and the underlying etching stop layer 7 were selectively etched to form wiring (here, Cu) 11 at the opening.
First, the interlayer insulating film 8 was etched by the RIE method, and was automatically stopped by the etching stop layer 7. Subsequently, the etching stopper layer 7 was etched under RIE conditions different from those for the interlayer insulating film 8. Next, the interlayer insulating film 8
And Ti to cover the inner surface of the opening formed therein.
An N film 9 was formed with a thickness of 10 nm, and a plating seed layer 10 made of Cu was formed on the surface with a thickness of 500 nm by sputtering. On the surface of the plating seed layer 10,
A Cu wiring 11 was formed by electrolytic plating so as to fill the remaining opening of the interlayer insulating film 8. The upper surface of the conductive plug 5S was in contact with the bottom surface of one Cu wiring 11, and the upper surface of the conductive plug 5D was in contact with the bottom surface of the other Cu wiring 11.

After the Cu wiring 11 is formed as described above, the Cu wiring 11 deposited above the upper surface of the interlayer insulating film 8 is formed.
The wiring 11, the plating seed layer 10, and the TiN film 9 are subjected to CMP.
Then, a diffusion preventing layer 12 made of BN was deposited on the interlayer insulating film 8 and the Cu wiring 11 to a thickness of 0.1 μm by the CVD method. Subsequently, according to the same method as described above, an interlayer insulating film 13 made of SiO ₂ having a thickness of 1 μm and a thickness of 0.1
Etch stop layer 14 of μm BN, thickness 0.6
μm interlayer insulating film 15 of the present invention, 0.1 μm thick BN
, An TiN film 17 having a thickness of 10 nm, and a plating seed layer 18 made of Cu having a thickness of 500 nm. Cu is deposited by electrolytic plating so as to fill the remaining openings of the interlayer insulating films 13 and 15.
The wiring 19 was formed. Cu wiring 19 and plating seed layer 18 deposited above the upper surface of etching stop layer 16
And the TiN film 17 was removed by CMP. Finally, a diffusion preventing layer 17 made of BN was deposited to a thickness of 0.1 μm on the etching stop layer 16 and the Cu wiring 19 by the CVD method. As a result, a semiconductor device having a multilayer wiring structure shown in FIG. 6 was obtained. Was.

[0039]

As described above, according to the present invention, a novel insulating film having a low dielectric constant of 2.4 or less and having no defect caused by moisture absorption or the like can be formed. A silicon compound and an insulating film forming material using the same can be obtained. Further, according to the present invention, through the use of such an insulating film forming material, an insulating film having a very low dielectric constant and high reliability, and using the insulating film, it is possible to function at high speed. A semiconductor device with high reliability can be obtained. The present invention can particularly contribute to improving the response speed of a semiconductor device having a multilayer wiring structure.

[Brief description of the drawings]

FIG. 1 is a graph plotting the change over time of the dielectric constant of an insulating film manufactured from the silicon compound of the present invention in Example 1.

FIG. 2 is a graph plotting the change over time of the dielectric constant of an insulating film manufactured from the silicon compound of the present invention in Example 2.

FIG. 3 is a graph plotting the change over time of the dielectric constant of an insulating film manufactured from the silicon compound of the present invention in Example 3.

FIG. 4 is a graph plotting the change over time of the dielectric constant of an insulating film manufactured from the silicon compound of the present invention in Example 4.

FIG. 5 is a graph plotting the change over time of the dielectric constant of an insulating film formed from a silicon compound for comparison in Comparative Example 1.

FIG. 6 is a cross-sectional view schematically showing a preferred embodiment of a semiconductor device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 silicon substrate 2 field oxide film 3 MOS transistor 4 interlayer insulating film 5S conductive plug 5D conductive plug 6 etching stop layer 7 etching stop layer 8 interlayer insulating film 9 TiN film 10 plating Seed layer 11: Copper (Cu) wiring 19: Copper (Cu) wiring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihiro Nakata 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Katsumi Suzuki 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Limited F-term (reference) 4G072 AA28 BB09 CC13 EE07 GG01 HH28 JJ11 JJ13 JJ16 MM01 MM22 NN21 RR05 RR12 UU01 UU30 4H049 VN01 VP01 VQ06 VQ16 VQ20 VQ21 VR10 VR20 VR40 V40

Claims (3)

[Claims] 1. A silicon compound having a three-dimensional void in a molecular structure, which is represented by the following formula (1): (In the above formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different from each other, and are each selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkoxy group, a hydroxyl group and an adamantyl ring-containing group. Represents a selected member, provided that _{one to three} members of the substituents R ₁ , R ₂ , R ₃ and R ₄ are adamantyl ring-containing groups and R ₁ , R ₂ , R ₃ and R ₄ And when three members are an adamantyl ring-containing group, the remaining member is an alkoxy group or a hydroxyl group). 2. At least one silicon compound represented by the following formula (1): (In the above formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different from each other, and are each selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkoxy group, a hydroxyl group and an adamantyl ring-containing group. Represents a selected member, provided that
In R _1, R _{2, 1-membered} to 3 membered of R ₃ and R ₄ are an adamantyl ring-containing group and, R _1, R _2, 3-membered of R ₃ and R ₄ are an adamantyl ring-containing group In some cases, the remaining member is an alkoxy group or a hydroxyl group). 3. At least one silicon compound represented by the following formula (1): (In the above formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different from each other, and are each selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkoxy group, a hydroxyl group and an adamantyl ring-containing group. Represents a selected member, provided that
In R _1, R _{2, 1-membered} to 3 membered of R ₃ and R ₄ are an adamantyl ring-containing group and, R _1, R _2, 3-membered of R ₃ and R ₄ are an adamantyl ring-containing group In some cases, the remaining member is an alkoxy group or a hydroxyl group).