JP3260352B2 - Method of forming interlayer insulating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an interlayer insulating film in a semiconductor device.

[0002]

2. Description of the Related Art As an interlayer insulating film in a semiconductor device, a silicon oxide film, a silicon oxide film containing an organic component such as organic SOG (Spin On Glass) and an organic polymer film are known.

By the way, interlayer insulating films of semiconductor devices include:
A low relative dielectric constant capable of reducing the wiring capacitance and a high heat resistance enough to withstand a semiconductor process are required.

[0004] With the progress of miniaturization of LSIs formed on a semiconductor substrate, an increase in wiring capacitance, which is a parasitic capacitance between metal wirings, has become remarkable. Is a serious problem. The wiring capacitance is determined by the size of the space between the metal wirings and the relative permittivity of the interlayer insulating film existing in the space. Therefore, in order to reduce the wiring capacitance,
It is important to reduce the relative dielectric constant of the interlayer insulating film.

In the case where the heat resistance of the interlayer insulating film is low, if a heat treatment of, for example, about 400 ° C. is performed in a semiconductor process, the interlayer insulating film is softened and the wiring structure is fluidized. That would cause a catastrophic failure. Therefore, as an interlayer insulating film,
Heat resistance that can withstand heat treatment at about 400 ° C. is required.

Meanwhile, a fluorine-doped silicon oxide film formed by adding fluorine to silicon oxide has been proposed because an interlayer insulating film made of a silicon oxide film has a high relative dielectric constant. However, the fluorine-added silicon oxide film has a low dielectric constant by bonding a fluorine atom having a small polarizability to a silicon atom constituting the oxide film, but has a hygroscopic property with an increase in the amount of added fluorine. Because it increases
The relative dielectric constant is limited to about 3.5. Therefore, as an interlayer insulating film in a highly miniaturized LSI,
It is difficult to employ a silicon oxide film such as a fluorine-added silicon oxide film.

Therefore, as an interlayer insulating film in a highly miniaturized LSI, an organic SO having a low relative dielectric constant is used.
The use of a G film or an organic polymer film is considered.

The organic SOG film is formed by thermally curing a solution containing silica or siloxane having an organic component such as a methyl group or a phenyl group, and the organic component remains in the film even after the thermal curing. And a low relative dielectric constant of about 3.0.

Hereinafter, as a first conventional example, a method of forming an interlayer insulating film made of an organic SOG film will be described with reference to FIGS.
This will be described with reference to FIG.

First, as shown in FIG. 6A, after a first-layer metal wiring 2 is formed on a semiconductor substrate 1, for example, a plasma CVD method using a mixed gas of tetraethoxysilane and oxygen as a raw material is performed. As a result, a first silicon oxide film 3 is formed over the entire surface of the semiconductor substrate 1 including the metal wiring 2 of the first layer. Thereafter, an organic SOG chemical is spin-coated on the first silicon oxide film 3 and then thermally cured to form an organic SOG.
The film 4 is formed.

Next, as shown in FIG.
The entire surface of the G film 4 is etched back to remove the organic SOG film 4 formed on the first metal wiring 2.

Next, as shown in FIG. 6C, the first silicon oxide film 3 including the remaining organic SOG film 4 is formed by, for example, a plasma CVD method using a mixed gas of tetraethoxysilane and oxygen as a raw material. A second silicon oxide film 5 is formed over the entire surface.

Next, as shown in FIG. 6D, a contact hole is formed in the second silicon oxide film 5 and the first silicon oxide film 3 using the resist pattern as a mask. Removed by plasma. Then, after forming a contact 6 by burying a metal material in the contact hole and then forming a second-layer metal wiring 7 on the second silicon oxide film 5, the first-layer metal wiring 2 and the second metal wiring 7 are formed. An interlayer insulating film including the first silicon oxide film 3, the organic SOG film 4, and the second silicon oxide film 5 is formed between the wiring 7.

Hereinafter, as a second conventional example, a method for forming an interlayer insulating film composed of a fluorinated amorphous carbon film as an organic polymer film will be described. The fluorinated amorphous carbon film is disclosed, for example, in the technical literature “Extended Abstr.
acts of the 1995 International Conference on Solid
State Devices and Materials, Osaka, 1995, pp177-17
As shown in “9”, it is formed by a plasma CVD method using a mixture of a hydrocarbon component such as CH ₄ and a fluorine-containing component such as CF ₄ as raw materials.

That is, after a source gas is introduced into a reaction chamber of a parallel plate type plasma CVD apparatus, the pressure in the reaction chamber is maintained at several hundred mTorr, and a parallel plate electrode in the reaction chamber is applied at 13.56 MHz at about 100 to 300 W. When the high frequency power is applied, the raw material gas is partially decomposed to generate monomers, ions and radicals. Thereafter, the generated monomers, ions, and radicals undergo a plasma polymerization reaction, and a fluorinated amorphous carbon film, which is a plasma-polymerized film, is deposited on the semiconductor substrate. The relative dielectric constant of the fluorinated amorphous carbon film thus formed immediately after deposition is 2.0 to 2.5, which is a low value.

[0016]

Incidentally, the former organic SOG film is formed by performing a process of spin-coating an organic SOG chemical solution and a process of thermally curing the applied organic SOG film a plurality of times, respectively. Therefore, it takes a lot of time to form the organic SOG film, so that the film forming property is poor.
In addition, there is a problem that when spin-coating an organic SOG chemical, most of the chemical is wasted, thereby increasing the cost.

On the other hand, as shown in FIG.
After performing a contact hole using the resist pattern as a mask in the organic SOG film 4 and the first silicon oxide film 3 without performing etch back on the entire surface of the G film 4, the resist pattern is removed by oxygen plasma.
When a contact is formed by embedding a metal material in a contact hole, the following problems occur. That is, in the step of removing the resist pattern by oxygen plasma, SiCH ₃ contained in the organic SOG film 4 exposed on the side wall of the contact hole reacts with oxygen plasma to generate SiOH. This SiOH is
In the step of embedding a metal material in the contact hole, H ₂ O is generated by dehydration condensation. The generated H ₂ O causes oxidation and contamination of the metal in the contact, which causes poor conduction in the contact.

An organic polymer film made of the latter fluorinated amorphous carbon film has an advantage of having a very small relative dielectric constant, but has a problem that heat resistance is inferior due to a low glass transition point. That is, when a conventional fluorinated amorphous carbon film is subjected to a heat treatment at a temperature of 300 ° C. or more, there is a problem that the film thickness is greatly reduced and the relative dielectric constant is greatly increased. For example, CH
_When a fluorinated amorphous carbon film formed of ₄ and CF ₄ as raw materials and having a relative dielectric constant of 2.2 immediately after deposition is subjected to a heat treatment at a temperature of 300 ° C. for 1 hour, the film thickness becomes About 35% reduction, 65% of film thickness immediately after deposition
With the contraction, the relative dielectric constant also increases to about 2.8.

The above-mentioned problems are not limited to the interlayer insulating film formed between the lower metal wiring layer and the upper metal wiring layer. This also occurs in the interlayer insulating film formed on the substrate.

In view of the above, it is a first object of the present invention to improve the film forming property, cost, and workability of an interlayer insulating film made of an organic SOG film, and to improve the interlayer insulating film made of an organic polymer film. A second object is to improve heat resistance.

[0021]

In order to achieve the first object, a first method of forming an interlayer insulating film according to the present invention comprises:
General formula: R ¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x
Is an integer of 1 to 3. ) Or a general formula: R ¹ _x SiH _4-x
(However, R ¹ is a phenyl group or a vinyl group, and x is 1
-3. The interlayer insulating film made of the organic-containing silicon oxide film is formed by subjecting a raw material mainly composed of the organic silicon compound represented by the formula (1) to a plasma polymerization reaction or a reaction with an oxidizing agent.

According to the first method for forming an interlayer insulating film, a general formula: R ¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, and R ² is an alkyl group) , X is an integer of 1 to 3), or a general formula: R ¹ _x SiH _4-x
(However, R ¹ is a phenyl group or a vinyl group, and x is 1
-3. ), The ratio of SiCH ₃ contained in the interlayer insulating film is greatly reduced as compared with the conventional organic SOG film, and the interlayer insulating film is exposed to oxygen plasma. Even, Si
Only a small amount of OH is produced. In the first method for forming an interlayer insulating film, an organic-containing silicon oxide film is formed by subjecting a raw material containing an organic silicon compound as a main component to plasma polymerization reaction or reaction with an oxidizing agent. It is not necessary to perform the step of applying and the step of curing.

In the first method for forming an interlayer insulating film, the organosilicon compound represented by the general formula: R ¹ _x Si (OR ² ) _4-x is phenyltrimethoxysilane or diphenyldimethoxysilane. The organosilicon compound represented by R ¹ _x SiH _4-x is preferably phenylsilane or diphenylsilane.

In the first method for forming an interlayer insulating film, the organosilicon compound represented by the general formula: R ¹ _x Si (OR ² ) _{4- x} is vinyltrimethoxysilane or divinyldimethoxysilane. Formula: R ¹ _x SiH _4-x
The organic silicon compound represented by is preferably vinyl silane or divinyl silane.

In order to achieve the second object, a second method for forming an interlayer insulating film according to the present invention comprises, as a main component, a carbon fluoride compound having two or more double bonds between carbon atoms in a molecule. By subjecting the raw materials to be subjected to a plasma polymerization reaction,
An interlayer insulating film made of a fluorinated amorphous carbon film is formed.

According to the second method for forming an interlayer insulating film, since a carbon fluoride compound has two or more double bonds between carbon atoms in a molecule, the carbon fluoride compound is decomposed by plasma. Then, a radical having three or more dangling bonds is easily generated. Since such radicals promote a three-dimensional polymerization reaction, a fluorinated amorphous carbon film having excellent heat resistance is obtained.

In the second method for forming an interlayer insulating film, the carbon fluoride compound preferably comprises only carbon atoms and fluorine atoms.

In this case, the carbon fluoride compound is more preferably hexafluoro-1,3-butadiene.

In order to achieve the second object, a third method for forming an interlayer insulating film according to the present invention comprises a method of forming a raw material mainly containing a fluorocarbon compound having a triple bond between carbon atoms in a molecule. By performing a plasma polymerization reaction, an interlayer insulating film made of a fluorinated amorphous carbon film is formed.

According to the third method for forming an interlayer insulating film, the carbon fluoride compound has a triple bond between carbon atoms in the molecule. Radicals having three or more bonds are easily generated. Since such radicals promote a three-dimensional polymerization reaction, a fluorinated amorphous carbon film having excellent heat resistance is obtained.

In the third method for forming an interlayer insulating film, the carbon fluoride compound preferably comprises only carbon atoms and fluorine atoms.

In this case, the carbon fluoride compound is more preferably hexafluoro-2-butyne.

In order to achieve the second object, a fourth method for forming an interlayer insulating film according to the present invention is a method for forming a film mainly comprising a fluorocarbon compound having a polycyclic structure in a molecule by a plasma polymerization reaction. As a result, an interlayer insulating film made of a fluorinated amorphous carbon film is formed.

According to the fourth method for forming an interlayer insulating film, since the carbon fluoride compound has a polycyclic structure in the molecule, when the carbon fluoride compound is decomposed by plasma, unbonded bonds are generated. Radicals having three or more are likely to be generated. Since such radicals promote a three-dimensional polymerization reaction, a fluorinated amorphous carbon film having excellent heat resistance is obtained.

In the fourth method for forming an interlayer insulating film, the carbon fluoride compound preferably comprises only carbon atoms and fluorine atoms.

In the fourth method for forming an interlayer insulating film, the carbon fluoride compound preferably has a condensed polycyclic structure in the molecule.

In this case, the carbon fluoride compound is more preferably perfluorodecalin or perfluoroflorene.

A fifth method of forming an interlayer insulating film according to the present invention is a general method: R ¹ _x Si (OR ² ) _{4- x} (where R ¹ is a phenyl group or a vinyl group, and R ² is an alkyl group) Wherein x is an integer of 1 to 3) or a raw material mainly containing a mixed gas of a compound represented by the following formula (1) or an organosilicon compound consisting of a siloxane derivative and a carbon fluoride compound: Alternatively, by reacting with an oxidizing agent, an interlayer insulating film made of a silicon oxide film containing carbon fluoride is formed.

According to the fifth method of forming an interlayer insulating film, a raw material containing a mixed gas of an organosilicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or reacted with an oxidizing agent to form a carbon fluoride. The relative dielectric constant is extremely low for forming the containing silicon oxide film, that is, the interlayer insulating film contains the organic silicon compound and the carbon fluoride compound. Further, similarly to the first method for forming the interlayer insulating film, there is no need to perform a step of applying a chemical solution of organic SOG and a step of curing, which are necessary when forming the organic SOG film.

A sixth method of forming an interlayer insulating film according to the present invention comprises, as a main component, a mixed gas of an organosilicon compound and a carbon fluoride compound having two or more double bonds between carbon atoms in a molecule. The raw material is subjected to a plasma polymerization reaction or an oxidizing agent to form an interlayer insulating film made of a silicon oxide film containing carbon fluoride.

According to the sixth method for forming an interlayer insulating film, a raw material containing a mixed gas of an organic silicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to form a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. Further, as in the case of the second method of forming the interlayer insulating film, since the carbon fluoride compound has two or more double bonds between carbon atoms in the molecule, the carbon fluoride compound is decomposed by plasma. Then, a radical having three or more dangling bonds is easily generated. Since such radicals promote a three-dimensional polymerization reaction, a carbon fluoride-containing silicon oxide film having excellent heat resistance is obtained.

A seventh method for forming an interlayer insulating film according to the present invention is a method for forming a raw material mainly containing a mixed gas of an organosilicon compound and a carbon fluoride compound having a triple bond between carbon atoms in a molecule. An interlayer insulating film made of a carbon fluoride-containing silicon oxide film is formed by a plasma polymerization reaction or a reaction with an oxidizing agent.

According to the seventh method for forming an interlayer insulating film, a raw material containing a mixed gas of an organic silicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to form a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. Further, as in the case of the third method for forming an interlayer insulating film, since the carbon fluoride compound has a triple bond between carbon atoms in the molecule, when the carbon fluoride compound is decomposed by plasma,
A radical having three or more dangling bonds is likely to be generated.
Since such radicals promote a three-dimensional polymerization reaction, a carbon fluoride-containing silicon oxide film having excellent heat resistance is obtained.

An eighth method of forming an interlayer insulating film according to the present invention is a method of forming a plasma polymerization reaction using a raw material mainly containing a mixed gas of an organosilicon compound and a carbon fluoride compound composed of a compound having a polycyclic structure. Or by reacting with an oxidizing agent, an interlayer insulating film made of a carbon fluoride-containing silicon oxide film is formed.

According to the eighth method of forming an interlayer insulating film, a raw material containing a mixed gas of an organosilicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to produce a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. Further, as in the case of the fourth method for forming an interlayer insulating film, the carbon fluoride compound has a polycyclic structure in the molecule. Radicals having more than one are easily generated. Since such radicals promote a three-dimensional polymerization reaction, a carbon fluoride-containing silicon oxide film having excellent heat resistance is obtained.

In the sixth to eighth methods of forming an interlayer insulating film, the organosilicon compound has a general formula: R ¹ _x Si (O
R ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to 3) or a siloxane derivative. preferable.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for forming an interlayer insulating film according to each embodiment of the present invention will be described. As a premise, a CVD apparatus used in the method for forming an interlayer insulating film according to each embodiment is described below. 1 will be described.

FIG. 1 shows a schematic configuration of a parallel plate type plasma CVD apparatus. As shown in FIG. 1, in a reaction chamber 11 in which the inside is kept airtight, a semiconductor substrate 12 made of silicon is placed and a sample table 13 serving as a lower electrode is provided. Reference numeral 13 is connected to a first high-frequency power supply 15 or ground via a changeover switch 14. A heater (not shown) is provided inside the sample stage 13, and the semiconductor substrate 12 placed on the sample stage 13 is heated to a predetermined temperature by the heater. A shower head 16 serving as an upper electrode is provided at a position facing the sample table 13 inside the reaction chamber 11,
The shower head 16 is connected to a second high frequency power supply 17 for supplying a high frequency power of 13.56 MHz.

The reaction chamber 11 is provided with a first gas supply line 21, a second gas supply line 22, and a third gas supply line 23 for introducing a source gas into the reaction chamber 11. . The first gas supply line 21 is provided with a first storage container 24 for storing a raw material composed of a liquid,
When a carrier gas having a controlled flow rate is supplied to the first storage container 24 via a mass flow controller (not shown), the source gas bubbled into the reaction chamber 11 is introduced from the first storage container 24. Second gas supply line 2
2 is a second storage container 2 for storing a liquid raw material.
5 and a carrier gas whose flow rate is controlled via a mass flow controller (not shown)
5 is supplied to the reaction chamber 11 from the second storage container 25.
The source gas bubbled therein is introduced. Further, a vacuum pump 26 is connected to the reaction chamber 11, and the inside of the reaction chamber 11 can be evacuated by driving the vacuum pump 26 to exhaust gas in the reaction chamber 11.

Hereinafter, a method for manufacturing a first semiconductor device to which the method for forming an interlayer insulating film according to each embodiment of the present invention is applied will be described with reference to FIGS. 2 (a) to 2 (d). .

First, as shown in FIG. 2A, after a first metal wiring 101 made of, for example, aluminum is formed on a semiconductor substrate 100, the first metal wiring 101 is formed by using the above-mentioned plasma CVD apparatus. ), The first metal wiring 1
Then, an interlayer insulating film 102 is deposited over the entire surface of the semiconductor substrate 100 including the first semiconductor layer 100. The method for forming the interlayer insulating film 102 will be described later.

Next, as shown in FIG. 2C, the interlayer insulating film 102 is subjected to a flattening process. Then, FIG.
As shown in (d), the contact 1
After forming 03, a second metal wiring 104 made of, for example, aluminum is formed on the interlayer insulating film 102.

Hereinafter, a method of manufacturing a second semiconductor device to which the method of forming an interlayer insulating film according to each embodiment of the present invention is applied will be described with reference to FIGS. 3 (a) to 3 (d). .

First, as shown in FIG. 3A, on a semiconductor substrate 200, a first silicon nitride film 201 is formed.
Layer interlayer insulating film 202, second layer silicon nitride film 203
Then, an interlayer insulating film 204 as a second layer is sequentially deposited. The first interlayer insulating film 202 and the second interlayer insulating film 204
The forming method will be described later.

Next, as shown in FIG. 3B, a wiring pattern forming opening 205 was formed by patterning the second layer of the silicon nitride film 203 and the second layer of the interlayer insulating film 204 by photolithography. After that, the first silicon nitride film 201 and the first interlayer insulating film 202 are patterned by photolithography to form a contact opening 206. In this case, the second silicon nitride film 203 serves as an etching stopper for etching the second interlayer insulating film 204, and the first silicon nitride film 201 serves as an etching stopper for the first interlayer insulating film 202. Plays the role of an etching stopper.

Next, as shown in FIG. 3C, a metal film 207 made of, for example, copper is deposited on the entire surface of the semiconductor substrate 200 by a sputtering method or a CVD method. The metal film 2 is reflowed by heat treatment.
07 is buried in the wiring pattern forming opening 205 and the contact opening 206.

Next, by performing CMP on the metal film 207 to form a metal wiring 208 and a contact 209 made of the metal film 207 as shown in FIG. 3D, an embedded wiring having a dual damascene structure is formed. Can be formed.

(First Embodiment) An interlayer insulating film according to a first embodiment has a general formula: R ¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to _3. ) A raw material containing phenyltrimethoxysilane (Ph-Si- (OCH ₃ ) ₃ ) as an organic silicon compound represented by the following formula: It is a plasma polymerized film formed by performing a polymerization reaction.

Hereinafter, a method for forming the interlayer insulating film according to the first embodiment will be described.

First, after mounting the semiconductor substrate 12 on the sample stage 13 heated to, for example, 400 ° C. and grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, while storing the phenyltrimethoxysilane represented by Chemical Formula 1 in the first storage container 24,
A carrier gas made of, for example, argon is supplied to the first storage container 24 at a flow rate of 480 cc / min, and the bubbled phenyltrimethoxysilane is introduced into the reaction chamber 11.

[0062]

Embedded image

Next, the pressure in the reaction chamber 11 is set to about 1.0 To
rr, the shower head 16 serving as the upper electrode
13.56 MHz from the second high frequency power supply 17
Is applied. In this case, the phenyltrimethoxysilane gas is partially decomposed, and monomers, ions and radicals are generated as decomposition products, and the generated monomers, ions and radicals undergo a polymerization reaction to form the semiconductor substrate 12. An interlayer insulating film made of a plasma polymerized film is formed thereon. The structure of this plasma polymerized film is schematically shown in [Chemical Formula 2].

[0064]

Embedded image

Since the interlayer insulating film according to the first embodiment is formed by the plasma CVD method, it is not necessary to perform the step of applying the organic SOG chemical solution and the step of thermally curing the organic SOG film a plurality of times. The performance can be improved and the cost can be reduced.

Further, the interlayer insulating film according to the first embodiment is different from a conventional organic SOG film in that Si
Since the amount of CH ₃ is greatly reduced, even if the interlayer insulating film is etched by oxygen plasma, only a small amount of SiOH is generated. For this reason, in the step of embedding the metal material in the contact hole, the phenomenon that SiOH causes a dehydration condensation reaction to generate H ₂ O and does not cause a conduction failure in the contact does not occur.

FIG. 4 shows the results of Fourier transform infrared spectroscopy (hereinafter referred to as FT-IR) of the interlayer insulating film according to the first embodiment and the conventional organic SOG film. Is shown. In the conventional organic SOG film, a wave number: 1300 with respect to a peak in absorbance appearing in the vicinity of (cm ^-1), in the interlayer insulating film according to the first embodiment, the wave number: 1300 (cm ^- The peak of the absorbance near ¹ ) is smaller than that of the organic SOG film. Therefore, it can be seen that the interlayer insulating film according to the first embodiment has a lower content of SiCH ₃ than the organic SOG film.

FIG. 5 is a graph showing the relationship between the interlayer insulating film not subjected to the heat treatment and the interlayer insulating film subjected to the heat treatment at 450 ° C. and 500 ° C. in a nitrogen atmosphere.
The analysis result at the time of performing T-IR is shown. FIG.
As shown in FIG.
Since no change was observed in the FT-IR spectrum between the interlayer insulating film subjected to the heat treatment at the temperature of 50 ° C. and 500 ° C., the interlayer insulating film according to the first embodiment withstands the LSI process. It turns out that it has sufficient heat resistance.

The relative dielectric constant of the interlayer insulating film according to the first embodiment was about 3.0. Further, the interlayer insulating film is
The relative dielectric constant was measured after standing at room temperature for a week and found to be about 3.1. The interlayer insulating film according to the first embodiment had a stable film quality with little change over time.

Further, the leakage current density was 5 M
A good result of about 4.5 × 10 ⁻⁸ A / cm ² at V / cm was obtained.

The pressure in the reaction chamber 11 is about 1.0 To
rr, but is not limited to this.
It can be appropriately selected within the range of 00 mTorr to 20 Torr, but is preferably within the range of 0.5 to 5.0 Torr.

The heating temperature of the semiconductor substrate 12 is 40
Although it was 0 ° C., the temperature is not limited to 0 ° C. and can be appropriately selected within the range of 25 ° C. to 500 ° C. However, the semiconductor substrate 1
If 2 is heated to a temperature exceeding 400 ° C., it exceeds the heat-resistant temperature of aluminum constituting the metal wiring formed on the semiconductor substrate 12. Therefore, the heating temperature is preferably 400 ° C. or less. The temperature of the semiconductor substrate 12 is 200 ° C.
When the heating temperature is less than 200 ° C., unnecessary components may be taken into the interlayer insulating film when the interlayer insulating film is formed.

Further, the shower head 16 serving as the upper electrode
The high-frequency power applied to the substrate can be appropriately selected within the range of 100 to 1000 W, but is preferably within the range of 250 to 500 W.

[0074] The general _{^{formula: R 1 x Si (OR 2}} )
In _4-x, as the compound R ¹ is a phenyl group, in addition to phenyltrimethoxysilane, diphenyldimethoxysilane _{(Ph 2 -Si- (OCH 3)} 2) or the like can be cited, wherein R ¹ is vinyl As the compound which is a group, vinyltrimethoxysilane (CH ₂ ＣＨCH—Si
- (OCH _{3) 3)} and divinyl dimethoxysilane _{((CH 2 = CH) 2} -Si- (OCH 3) 2) , and the like.

Further, in the first embodiment, the general
Formula: R¹ _xSi (OR^Two)_4-x Organic silicon represented by
The raw material mainly composed of a compound is subjected to plasma polymerization
An interlayer insulating film consisting of a plasma polymerized film was formed.
Alternatively, the general formula: R¹ _xSiH _4-x (However, R¹Is Pheni
And x is an integer of 1 to 3. )
The raw material mainly composed of the organic silicon compound represented by
Interlayer insulation consisting of plasma polymerized film by plasma polymerization reaction
An edge film may be formed, or the above-mentioned general formula: R¹ _xSi (O
R^Two)_4-x Or a general formula: R¹ _xSiH_4-x Yes represented by
The raw material mainly composed of silicon compound is_TwoAnd
H_TwoReacts with oxidizing agent such as O to form interlayer insulating film
May be. In this case, the CVD apparatus shown in FIG.
From the third gas supply line 23_TwoGas or H_TwoOga
And the like are introduced into the reaction chamber 11.

In the above general formula: R ¹ _x SiH _4-x , examples of the compound in which R ¹ is a phenyl group include phenylsilane and diphenylsilane.
Examples of the compound in which ¹ is a vinyl group include vinyl silane and divinyl silane.

(Second Embodiment) An interlayer insulating film according to a second embodiment is a fluorinated carbon compound having a double bond between carbon atoms in a molecule and containing a hydrogen atom. This is a fluorinated amorphous carbon film formed by subjecting a raw material mainly composed of 1,1,3,3-pentafluoropropene to a plasma polymerization reaction.

Hereinafter, a method for forming an interlayer insulating film according to the second embodiment will be described.

First, after the semiconductor substrate 12 is placed on the sample stage 13 grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, in the first storage container 24, 1,1,1,
3,3-pentafluoropropene is stored, and a carrier gas made of, for example, argon is supplied to the first storage container 24 at a flow rate of 50 to 500 sccm, so that the bubbled 1,1,1,3,3-pentane is supplied. Fluoropropene is introduced into the reaction chamber 11.

Next, the pressure in the reaction chamber 11 is increased to 100 to 50.
After adjusting the pressure to 0 mTorr, the shower head 16 serving as the upper electrode is supplied with a frequency of 13.5 from the second high-frequency power supply 17.
A high frequency power of 100 MHz to 500 W, which is 6 MHz, is applied. In this way, the 1,1,1,3,3-pentafluoropropene gas is partially decomposed, and monomers, ions and radicals are generated as decomposition products, and the generated monomers, ions and radicals are polymerized. As a result, an interlayer insulating film made of a plasma polymerized film is formed on the semiconductor substrate 12.

This plasma polymerized film has 1,1,1,3,
Because 3-pentafluoropropene is the main component,
The film was a fluorinated amorphous carbon film containing hydrogen atoms together with carbon atoms and fluorine atoms, and the relative dielectric constant immediately after film deposition was 2.5.

The plasma polymerized film exists in the plasma because it is formed by the reaction of ions and radicals, which are decomposition products generated by the decomposition of the raw material gas in the plasma, on the semiconductor substrate 12. The properties of the decomposition products have a great influence on the structure of the plasma polymerized film. Further, the heat resistance of the plasma polymerized film is closely related to the crosslink density which determines the structure of the plasma polymerized film.

A conventional plasma-polymerized film made of a fluorinated amorphous carbon film has a low glass transition point because the bonding of the polymers constituting the plasma-polymerized film is linear and one-dimensional. It is considered inferior.

On the other hand, the interlayer insulating film according to the second embodiment has a high cross-linking density and a high glass transition point because the bonding of the polymers constituting the plasma polymerized film tends to be three-dimensional. Therefore, it has excellent heat resistance. That is, since 1,1,1,3,3-pentafluoropropene has a double bond between carbon atoms in the molecule,
Decomposition products generated by decomposition of 1,1,3,3-pentafluoropropene in plasma are likely to cause a crosslinking reaction when forming a plasma polymerized film on the semiconductor substrate 12.
For this reason, the obtained plasma polymerized film has a high glass transition point and is excellent in heat resistance.

In order to evaluate the heat resistance of the interlayer insulating film according to the second embodiment, the semiconductor substrate 12 on which the fluorinated amorphous carbon film according to the second embodiment was formed at a temperature of 400 ° C. in a vacuum. For 1 hour, the decrease in the thickness of the fluorinated amorphous carbon film was only about 6%, and the relative dielectric constant was about 2.6, which was an increase of about 0.1. Thereby, it was confirmed that the fluorinated amorphous carbon film according to the second embodiment was excellent in heat resistance.

In the second embodiment, 1,1,1,3,3-pentane is used as a fluorinated carbon compound having a double bond between carbon atoms in a molecule and containing a hydrogen atom. Fluoropropene was used, but instead of 1
H, 1H, 2H-perfluorohexene, 1H, 1H,
2H-perfluoro-1-octene, trifluoroethylene or 3,3,3-trifluoropropane can be used.

As a raw material of the interlayer insulating film according to the second embodiment, a fluorinated carbon compound having a double bond between carbon atoms in a molecule and containing a hydrogen atom may be used alone. The fluorinated carbon compound has other components such as N ₂
Etc. may be included.

(Third Embodiment) An interlayer insulating film according to a third embodiment is a hexafluorinated carbon compound having a double bond between carbon atoms in a molecule and containing no hydrogen atom. This is a fluorinated amorphous carbon film formed by subjecting a raw material mainly composed of fluoropropene to a plasma polymerization reaction.

The third embodiment is a modification of the second embodiment in which the raw materials are changed. Therefore, only the raw materials will be described below.

When hexafluoropropene is introduced into the reaction chamber 11, hexafluoropropene is partially decomposed and turned into plasma, and monomers, ions and radicals are generated as decomposition products, and the generated monomers, ions and The radicals are polymerized to form an interlayer insulating film made of a plasma polymerized film on the semiconductor substrate 12.

In the third embodiment, since hexafluoropropene does not contain a hydrogen atom, it is a fluorinated amorphous carbon film containing only carbon atoms and fluorine atoms. The dielectric constant was 2.3.

Also in the third embodiment, the bonding of the polymers constituting the plasma polymerized film is likely to be three-dimensional, so that the glass transition point is high and the heat resistance is excellent.

In order to evaluate the heat resistance of the interlayer insulating film according to the third embodiment, the semiconductor substrate 12 on which the fluorinated amorphous carbon film according to the third embodiment is formed at a temperature of 400 ° C. in a vacuum. , The decrease in the thickness of the fluorinated amorphous carbon film was only about 5%, and the relative dielectric constant was about 2.5, which was an increase of about 0.2. Thereby, it was confirmed that the fluorinated amorphous carbon film according to the third embodiment was excellent in heat resistance. That is, since the fluorinated amorphous carbon film according to the third embodiment does not contain hydrogen atoms and is composed of only fluorinated carbon, the heat resistance is higher than that of the fluorinated amorphous carbon film according to the second embodiment. The dielectric constant has been improved and the dielectric constant has been further reduced.

As a raw material of the interlayer insulating film according to the third embodiment, a fluorinated carbon compound having a double bond between carbon atoms in a molecule and containing no hydrogen atom is used alone. Alternatively, the fluorinated carbon compound may contain other components such as N ₂ .

(Fourth Embodiment) The interlayer insulating film according to the fourth embodiment is made of a fluorinated carbon compound having two double bonds between carbon atoms in a molecule and containing no hydrogen atoms. This is a fluorinated amorphous carbon film formed by subjecting a raw material mainly composed of hexafluoro-1,3-butadiene to a plasma polymerization reaction.

In the fourth embodiment, the raw materials in the second embodiment are changed. Therefore, only the raw materials will be described below.

[0098]

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When hexafluoro-1,3-butadiene shown in [Chemical Formula 3] is introduced into the reaction chamber 11, hexafluoro-1,3-butadiene is partially decomposed, and a monomer, Ions and radicals are generated, and the generated monomers, ions and radicals undergo a polymerization reaction to form an interlayer insulating film made of a plasma-polymerized film on the semiconductor substrate 12.

In the fourth embodiment, since hexafluoro-1,3-butadiene has two double bonds between carbon atoms in a molecule, these two double bonds are formed in plasma. When partially decomposed, a radical having four dangling bonds is generated as shown in, for example, [Formula 4], and the generated radical causes a polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film surely becomes three-dimensional, so that the crosslink density is higher than in the second and third embodiments, and the glass transition point is further increased. Is further improved.

[0101]

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As the raw material of the interlayer insulating film according to the fourth embodiment, a fluorinated carbon compound having two double bonds between carbon atoms in a molecule and containing no hydrogen atom is used alone. The fluorinated carbon compound may contain other components such as N ₂ .

(Fifth Embodiment) The interlayer insulating film according to the fifth embodiment is a fluorinated carbon compound having a triple bond between carbon atoms in a molecule and containing a hydrogen atom. Is a fluorinated amorphous carbon film formed by subjecting a raw material mainly composed of 3,3-trifluoropropyne to a plasma polymerization reaction.

In the fifth embodiment, the raw materials in the second embodiment are changed, and only the raw materials will be described below.

When 3,3,3-trifluoropropyne (CF ₃ C≡CH) is introduced into the reaction chamber 11,
3,3-trifluoropropyne is partially decomposed to generate monomers, ions and radicals as decomposition products, and the generated monomers, ions and radicals undergo a polymerization reaction to form a plasma-polymerized film on the semiconductor substrate. An interlayer insulating film is formed.

In the fifth embodiment, 3,3,3-
Since trifluoropropyne contains a hydrogen atom, it is a fluorinated amorphous carbon film containing hydrogen atoms together with carbon atoms and fluorine atoms, and the relative dielectric constant of the fluorinated amorphous carbon film immediately after deposition is 2.5. .

In the fifth embodiment, 3,3,3-
Since trifluoropropyne has a triple bond between carbon atoms as shown in [Formula 5], when this triple bond is partially decomposed in plasma, for example, as shown in [Formula 6] In addition, a radical having four dangling bonds is generated, and the generated radical causes a polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film surely becomes three-dimensional, so that the crosslink density is higher than in the second and third embodiments, and the glass transition point is further increased. Is further improved.

[0108]

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[0109]

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In order to evaluate the heat resistance of the interlayer insulating film according to the fifth embodiment, the semiconductor substrate on which the fluorinated amorphous carbon film according to the fifth embodiment was formed at a temperature of 400 ° C. in a vacuum. After holding for 1 hour, the decrease in the thickness of the fluorinated amorphous carbon film is only about 5%, and the relative dielectric constant is about 2.6 to about 0.1%.
Only increased. Thereby, it was confirmed that the fluorinated amorphous carbon film according to the fifth embodiment was excellent in heat resistance.

In the fifth embodiment, 3,3,3-trifluoropropyne is used as a fluorinated carbon compound having a triple bond between carbon atoms in a molecule and containing a hydrogen atom. However, perfluoro (t-butyl) acetylene (HC≡CC (CF ₃ ) ₃ may be used instead.

Further, as a raw material of the interlayer insulating film according to the fifth embodiment, a fluorinated carbon compound having a triple bond between carbon atoms in a molecule and containing a hydrogen atom may be used alone. The fluorinated carbon compound may contain other components such as N ₂ .

(Sixth Embodiment) The interlayer insulating film according to the sixth embodiment is a hexafluoro compound which is a fluorinated carbon compound having a triple bond between carbon atoms in a molecule and containing no hydrogen atom. -2-A fluorinated amorphous carbon film formed by subjecting a raw material mainly containing butyne to a plasma polymerization reaction.

In the sixth embodiment, the raw materials in the second embodiment are changed. Therefore, only the raw materials will be described below.

[0115] Hexafluoro-2-
When butyne (CF ₃ C≡CCF ₃ ) is introduced, hexafluoro-2-butyne is partially decomposed to generate monomers, ions and radicals as decomposition products, and the generated monomers, ions and radicals are polymerized. As a result, an interlayer insulating film made of a plasma polymerized film is formed on the semiconductor substrate 12.

In the sixth embodiment, since hexafluoro-2-butyne contains no hydrogen atom, it is a fluorinated amorphous carbon film containing only carbon atoms and fluorine atoms. The relative dielectric constant of the film was 2.3.

In the sixth embodiment, hexafluoro-2-butyne is the same as 3,3,3 shown in the above [Chemical Formula 5].
-Has a triple bond between carbon atoms, like trifluoropropyne, so that when this triple bond is partially decomposed in plasma, as in 3,3,3-trifluoropropyne, A radical having four dangling bonds is generated, and the generated radical causes a polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film surely becomes three-dimensional, so that the crosslink density is higher than in the second and third embodiments, and the glass transition point is further increased. Is further improved.

In order to evaluate the heat resistance of the interlayer insulating film according to the sixth embodiment, the semiconductor substrate 12 on which the fluorinated amorphous carbon film according to the sixth embodiment was formed at a temperature of 400 ° C. in a vacuum. , The decrease in the thickness of the fluorinated amorphous carbon film was only about 5%, and the relative dielectric constant was about 2.4, which was an increase of about 0.1. Thereby, it was confirmed that the fluorinated amorphous carbon film according to the sixth embodiment was excellent in heat resistance.

In the sixth embodiment, a fluorinated carbon compound having a triple bond between carbon atoms in the molecule and containing no hydrogen atom may be used alone, or the fluorinated carbon compound may be used alone. The compound may contain other components such as N ₂ .

(Seventh Embodiment) The interlayer insulating film according to the seventh embodiment has a polycyclic structure (condensed ring structure) of carbon atoms in a molecule and is fluorinated without hydrogen atoms. This is a fluorinated amorphous carbon film formed by subjecting a raw material containing perfluorodecalin as a main component to a plasma polymerization reaction.

In the seventh embodiment, the raw materials in the second embodiment are changed. Therefore, only the raw materials will be described below.

When perfluorodecalin shown in [Chemical Formula 7] was introduced into the reaction chamber 11, the perfluorodecalin was partially decomposed, and monomers, ions and radicals were generated as decomposition products, which were generated. The monomers, ions and radicals undergo a polymerization reaction to form an interlayer insulating film made of a plasma polymerized film on the semiconductor substrate 12.

[0123]

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In the seventh embodiment, since perfluorodecalin does not contain hydrogen atoms, the perfluorodecalin is a fluorinated amorphous carbon film containing only carbon atoms and fluorine atoms. The dielectric constant was 2.3.

In the seventh embodiment, perfluorodecalin has a polycyclic structure (condensed ring structure) between carbon atoms as shown in [Chemical formula 7]. Is partially decomposed, a radical having four dangling bonds is generated as shown in, for example, [Formula 8], and the generated radical causes a polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film surely becomes three-dimensional, so that the cross-linking density is higher than in the second and third embodiments, and the glass transition point is further increased. Is further improved.

[0126]

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In order to evaluate the heat resistance of the interlayer insulating film according to the seventh embodiment, the semiconductor substrate 12 on which the fluorinated amorphous carbon film according to the seventh embodiment was formed at a temperature of 400 ° C. in a vacuum. , The decrease in the thickness of the fluorinated amorphous carbon film was only about 5%, and the relative dielectric constant was about 2.4, which was an increase of about 0.1. Thus, it was confirmed that the fluorinated amorphous carbon film according to the seventh embodiment had excellent heat resistance.

In the seventh embodiment, perfluorodecalin is used as a fluorinated carbon compound having a polycyclic structure of carbon atoms in a molecule and containing no hydrogen atom. Instead, perfluoroflorene represented by [Chemical formula 9], perfluoro-1-methyldecalin represented by [Chemical formula 10], and Perfluoro (tetradec) represented by [Chemical formula 11]
Fluorinated carbon compounds having a condensed ring structure such as ahydrophenanthrene) may be used, or fluorinated carbon compounds having a normal polycyclic structure such as perfluorobiphenyl shown in [Chemical Formula 12] may be used.

[0129]

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[0130]

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[0131]

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[0132]

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(Eighth Embodiment) The interlayer insulating film according to the eighth embodiment has a general formula: R ¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to ^3. ) A mixture of phenyltrimethoxysilane, which is an organosilicon compound represented by the following formula, and a benzene derivative having an F—C bond, which is a fluorocarbon compound This is a carbon fluoride-containing silicon oxide film formed by subjecting a raw material mainly composed of gas to a plasma polymerization reaction.

Hereinafter, a method for forming an interlayer insulating film according to the eighth embodiment will be described.

First, after mounting the semiconductor substrate 12 on the sample stage 13 heated to, for example, 400 ° C. and grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, a carrier gas made of, for example, argon is supplied to the first storage container 24 storing the phenyltrimethoxysilane represented by the formula 1 at a rate of 200 cc / min.
And the bubbled phenyltrimethoxysilane is introduced into the reaction chamber 11 while the F-
A second storage container 25 which is a benzene derivative having a C bond and stores difluorobenzene represented by [Chemical Formula 13].
200cc / carrier gas consisting of argon
By supplying at a flow rate of min, bubbling difluorobenzene is introduced into the reaction chamber 11.

[0137]

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Next, the pressure in the reaction chamber 11 was increased to about 1.0 To
rr, the shower head 16 serving as the upper electrode
13.56 MHz from the second high frequency power supply 17
Is applied. In this way, the phenyltrimethoxysilane gas and difluorobenzene are partially decomposed to generate monomers, ions and radicals as decomposition products, and the generated monomers, ions and radicals undergo a polymerization reaction, On the semiconductor substrate 12, an interlayer insulating film made of a plasma polymerized film is formed. The structure of the plasma polymerized film is schematically shown in [Formula 14].

[0139]

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Since the interlayer insulating film according to the eighth embodiment is formed by the plasma CVD method, it is not necessary to perform the step of applying the organic SOG chemical solution and the step of thermally curing the organic SOG film a plurality of times. The performance can be improved and the cost can be reduced.

The relative permittivity of the plasma-polymerized film according to the eighth embodiment is about 2.5, which is low. Further, the relative dielectric constant after being left at room temperature for two weeks is about 2.7, and the film quality is stable with little change over time. Therefore,
According to the eighth embodiment, it is possible to reduce the relative dielectric constant while improving the film forming property.

Furthermore, the leakage current density was 5 M
A good result of about 4.5 × 10 ⁻⁸ A / cm ² at V / cm was obtained.

The pressure in the reaction chamber 11 is about 1.0 To
rr, but is not limited to this.
It can be appropriately selected within the range of 00 mTorr to 20 Torr, but is preferably within the range of 0.5 to 5.0 Torr.

Further, the shower head 16 serving as the upper electrode
The high-frequency power applied to the substrate can be appropriately selected within the range of 100 to 1000 W, but is preferably within the range of 250 to 500 W.

Further, the heating temperature of the semiconductor substrate 12 is the first temperature.
As in the embodiment described above, the temperature can be appropriately selected within the range of 25 ° C to 500 ° C, but 200 to 400 ° C is preferable.

The above general formula: R ¹ _x Si (OR ² )
_{In 4-x} , examples of the compound in which R ¹ is a phenyl group include, in addition to phenyltrimethoxysilane, diphenyldimethoxysilane and the like.Examples of the compound in which R ¹ is a vinyl group include vinyltrimethoxysilane and Divinyldimethoxysilane and the like can be mentioned.

As the benzene derivative having an F—C bond, which is a carbon fluoride compound, fluorobenzene such as fluorobenzene and hexafluorobenzene can be used instead of difluorobenzene.

(Ninth Embodiment) An interlayer insulating film according to a ninth embodiment has a general formula: R ¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to ^3. ) A main component is a mixed gas of phenyltrimethoxysilane which is an organosilicon compound represented by the following formula: and C ₂ F ₆ which is a fluorocarbon compound. Is a fluorocarbon-containing silicon oxide film formed by subjecting a raw material to be subjected to a plasma polymerization reaction.

Hereinafter, a method for forming an interlayer insulating film according to the ninth embodiment will be described.

First, after mounting the semiconductor substrate 12 on the sample stage 13 heated to, for example, 400 ° C. and grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, a carrier gas made of, for example, argon is supplied to the first storage container 24 storing phenyltrimethoxysilane at a flow rate of 200 cc / min.
The bubbled phenyltrimethoxysilane is introduced into the reaction chamber 11, and the C ₂ F ₆ gas is introduced into the reaction chamber 11 from the third gas supply line 23.

Next, the pressure in the reaction chamber 11 was set to about 1.0
rr, the shower head 16 serving as the upper electrode
13.56 MHz from the second high frequency power supply 17
Is applied. In this case, the phenyltrimethoxysilane gas and C ₂ F ₆ are partially decomposed to generate monomers, ions and radicals as decomposition products, and the generated monomers, ions and radicals undergo a polymerization reaction. , Semiconductor substrate 1
2, an interlayer insulating film made of a plasma polymerized film is formed. The structure of this plasma polymerized film is schematically shown in [Formula 15].

[0153]

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Since the interlayer insulating film according to the ninth embodiment is formed by the plasma CVD method, it is not necessary to perform the step of applying the organic SOG chemical solution and the step of thermally curing the organic SOG film a plurality of times. The performance can be improved and the cost can be reduced.

The relative permittivity of the plasma polymerized film according to the ninth embodiment is about 2.9, which is a low permittivity. Further, the relative dielectric constant after being left at room temperature for two weeks is about 3.0, and the film quality is stable with little change over time. Therefore,
According to the ninth embodiment, the relative permittivity can be reduced while improving the film forming property.

Further, the leakage current density was 5 M
A good result of about 5.5 × 10 ⁻⁸ A / cm ² at V / cm was obtained.

The pressure in the reaction chamber 11 is about 1.0 To
rr, but is not limited to this.
It can be appropriately selected within the range of 00 mTorr to 20 Torr, but is preferably within the range of 0.5 to 5.0 Torr.

Further, the shower head 16 serving as the upper electrode
The high-frequency power applied to the substrate can be appropriately selected within a range of 100 to 2000 W, but is preferably within a range of 300 to 750 W.

The heating temperature of the semiconductor substrate 12 is the first
As in the embodiment described above, the temperature can be appropriately selected within the range of 25 ° C to 500 ° C, but 200 to 400 ° C is preferable.

The above general formula: R ¹ _x Si (OR ² )
_{In 4-x} , examples of the compound in which R ¹ is a phenyl group include, in addition to phenyltrimethoxysilane, diphenyldimethoxysilane and the like.Examples of the compound in which R ¹ is a vinyl group include vinyltrimethoxysilane and Divinyldimethoxysilane and the like can be mentioned.

Further, as the carbon fluoride compound, C ₂ F ₆
May be used instead of CF ₄ or C ₄ F ₈ .

Further, in the ninth embodiment, the general
Formula: R¹ _xSi (OR^Two)_4-x Organic silicon represented by
The raw material mainly composed of a compound is subjected to plasma polymerization
An interlayer insulating film consisting of a plasma polymerized film was formed.
Alternatively, the general formula: R¹ _xSiH _4-x (However, R¹Is Pheni
And x is an integer of 1 to 3. )
The raw material mainly composed of the organic silicon compound represented by
Interlayer insulation consisting of plasma polymerized film by plasma polymerization reaction
An edge film may be formed, or the above-mentioned general formula: R¹ _xSi (O
R^Two)_4-x Or a general formula: R¹ _xSiH_4-x Yes represented by
The raw material mainly composed of silicon compound is_TwoAnd
H_TwoReacts with oxidizing agent such as O to form interlayer insulating film
May be. In this case, the third gas supply line 23
From C _TwoF₆O with gas_TwoGas or H_TwoO gas
It is introduced into the lounge 11.

In the above-mentioned general formula: R ¹ _x SiH _4-x , examples of the compound in which R ¹ is a phenyl group include phenylsilane and diphenylsilane.
Examples of the compound in which ¹ is a vinyl group include vinyl silane and divinyl silane.

(Tenth Embodiment) An interlayer insulating film according to a tenth embodiment has a general formula: R ¹ _x Si (OR ² ) _4-x
(Provided that R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to 3); This is a carbon fluoride-containing silicon oxide film formed by subjecting a raw material mainly composed of a mixed gas with perfluorodecalin shown in the chemical formula [7] to a plasma polymerization reaction.

Hereinafter, a method for forming an interlayer insulating film according to the tenth embodiment will be described.

First, after mounting the semiconductor substrate 12 on the sample stage 13 heated to, for example, 400 ° C. and grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, a carrier gas made of, for example, argon is supplied to the first storage container 24 storing phenyltrimethoxysilane at a flow rate of 280 cc / min.
The bubbled phenyltrimethoxysilane is introduced into the reaction chamber 11, and a carrier gas made of, for example, argon is supplied at a flow rate of 42 cc / min to the second storage container 25 storing perfluorodecalin. Bubbled perfluorodecalin into reaction chamber 1
1 inside.

Next, the pressure in the reaction chamber 11 was increased to about 2.0
rr, the shower head 16 serving as the upper electrode
13.56 MHz from the second high frequency power supply 17
Is applied. In this case, the phenyltrimethoxysilane gas and perfluorodecalin are partially decomposed, and monomers, ions and radicals are generated as decomposition products, and the generated monomers, ions and radicals undergo a polymerization reaction, On the semiconductor substrate 12, an interlayer insulating film made of a plasma polymerized film is formed.

Since the interlayer insulating film according to the tenth embodiment is formed by the plasma CVD method, it is not necessary to perform the step of applying the organic SOG chemical solution and the step of thermally curing the organic SOG film a plurality of times. The performance can be improved and the cost can be reduced.

The relative permittivity of the plasma-polymerized film according to the tenth embodiment is about 2.6, which is low.
Further, the relative dielectric constant after being left at room temperature for two weeks is about 2.7, and the film quality is stable with little change over time. Therefore, according to the tenth embodiment, the relative permittivity can be reduced while improving the film forming property.

Further, the glass transition point was 430 ° C. or higher, indicating good heat resistance.

The pressure in the reaction chamber 11 is about 2.0 To
rr, but is not limited to this.
It can be appropriately selected within the range of 00 mTorr to 20 Torr, but is preferably within the range of 0.5 to 5.0 Torr.

Further, the shower head 16 serving as the upper electrode
The high-frequency power applied to the substrate can be appropriately selected within the range of 100 to 1000 W, but is preferably within the range of 250 to 500 W.

The heating temperature of the semiconductor substrate 12 is the first
As in the embodiment described above, the temperature can be appropriately selected within the range of 25 ° C to 500 ° C, but 200 to 400 ° C is preferable.

The above general formula: R ¹ _x Si (OR ² )
_{In 4-x} , examples of the compound in which R ¹ is a phenyl group include, in addition to phenyltrimethoxysilane, diphenyldimethoxysilane and the like.Examples of the compound in which R ¹ is a vinyl group include vinyltrimethoxysilane and Divinyldimethoxysilane and the like can be mentioned.

The fluorocarbon compound is not limited to perfluorodecalin, and the compounds shown in the second to seventh embodiments can be used as appropriate.

(Eleventh Embodiment) The interlayer insulating film according to the eleventh embodiment is a mixture of hexamethyldisiloxane, which is a siloxane derivative, and perfluorodecalin, which is a carbon fluoride compound [formula 7]. This is a carbon fluoride-containing silicon oxide film formed by subjecting a raw material mainly composed of gas to a plasma polymerization reaction.

Hereinafter, a method for forming an interlayer insulating film according to the eleventh embodiment will be described.

First, after mounting the semiconductor substrate 12 on the sample stage 13 heated to, for example, 400 ° C. and grounded by the changeover switch 14, the inside of the reaction chamber 11 is evacuated by the vacuum pump 26.

Next, a carrier gas made of, for example, argon is supplied at a flow rate of 28 cc / min to the first storage container 24 storing hexamethyldisiloxane, and the bubbled hexamethyldisiloxane is supplied to the reaction chamber 11. And a carrier gas made of, for example, argon is supplied at a flow rate of 280 cc / min to the second storage container 25 storing perfluorodecalin, and the bubbled perfluorodecalin is supplied to the reaction chamber 11. Introduce inside.

Next, the pressure in the reaction chamber 11 was increased to about 0.8
rr, the shower head 16 serving as the upper electrode
13.56 MHz from the second high frequency power supply 17
Is applied. In this case, hexamethyldisiloxane and perfluorodecalin are partially decomposed, and as decomposition products, monomers,
Ions and radicals are generated, and the generated monomers, ions, and radicals undergo a polymerization reaction to form an interlayer insulating film made of a plasma-polymerized film on the semiconductor substrate 12.

Since the interlayer insulating film according to the eleventh embodiment is formed by the plasma CVD method, it is not necessary to perform the step of applying the organic SOG chemical solution and the step of thermally curing the organic SOG film a plurality of times. The performance can be improved and the cost can be reduced.

The relative permittivity of the plasma-polymerized film according to the eleventh embodiment is about 2.75, which is low. The relative dielectric constant after being left at room temperature for two weeks is about 2.
8, which is a stable film quality with little change over time. Therefore, according to the eleventh embodiment, the relative permittivity can be reduced while improving the film forming property.

Further, the glass transition point was 430 ° C. or higher, indicating good heat resistance.

The pressure in the reaction chamber 11 is about 0.8 To
rr, but is not limited to this.
It can be appropriately selected within the range of 00 mTorr to 20 Torr, but is preferably within the range of 0.5 to 5.0 Torr.

Further, the shower head 16 serving as the upper electrode
The high-frequency power applied to the substrate can be appropriately selected within the range of 100 to 1000 W, but is preferably within the range of 250 to 500 W.

The heating temperature of the semiconductor substrate 12 is the first
As in the embodiment described above, the temperature can be appropriately selected within the range of 25 ° C to 500 ° C, but 200 to 400 ° C is preferable.

As the siloxane derivative, hexa
Instead of methyldisiloxane, 1,1,3,3-tetra
Methyldisiloxane (H (CH_Three)_TwoSi-O-Si
(CH _Three)_TwoH, or 1, 3, 5, 7 shown in [Formula 16]
-Tetramethylcyclotetrasiloxane or the like may be used.
No.

[0189]

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The fluorocarbon compound is not limited to perfluorodecalin, but any of those shown in the second to seventh embodiments can be used as appropriate.

Further, in the eleventh embodiment, the interlayer insulating film made of a plasma polymerized film is formed by subjecting a raw material containing a siloxane derivative as a main component to plasma polymerization reaction. May be reacted with an oxidizing agent such as O ₂ or H ₂ O to form an interlayer insulating film. In this case, O ₂ gas or H ₂ O gas is introduced into the reaction chamber 11 from the third gas supply line 23.

Incidentally, in the first to eleventh embodiments,
Although argon gas was used as the carrier gas, hydrogen, nitrogen, helium, or the like can be appropriately used instead.

In the first to eleventh embodiments, the sample stage 13 serving as the lower electrode is grounded.
When high-frequency power is applied from the high-frequency power supply 15, the plasma of the reaction gas generated in the reaction chamber 11 can be efficiently taken into the sample stage 13, so that the formation speed of the interlayer insulating film can be improved to about 2 to 5 times. .

[0194]

According to the first method for forming an interlayer insulating film,
Although the relative dielectric constant is equal to that of the conventional organic SOG film, SiCH ₃ contained in the interlayer insulating film is not included.
Is greatly reduced, even if the interlayer insulating film is exposed to oxygen plasma, only a small amount of SiOH is generated. For this reason, in the step of embedding a metal material in the contact hole, SiOH causes a dehydration condensation reaction to cause H ₂
O does not occur, and the problem of causing conduction failure in the contact does not occur. In the first method for forming an interlayer insulating film, an organic silicon oxide film is formed by subjecting a raw material containing an organic silico compound as a main component to plasma polymerization reaction or reaction with an oxidizing agent to form an organic-containing silicon oxide film.
It is not necessary to perform the step of applying the chemical solution and the step of curing, so that the film forming property is excellent.

[0195] In the method of forming the first interlayer insulating film, the organic silicon compound is phenyltrimethoxysilane or diphenyldimethoxysilane, the general formula: R ¹ _x Si
(OR ²⁾ _4-x organosilicon compound R ¹ is a phenyl group can be reliably implemented in, the organosilicon compound is phenylsilane or diphenylsilane, the general formula: R ¹ in R ¹ _x SiH _4-x Is a phenyl group.

[0196] In the method of forming the first interlayer insulating film, the organic silicon compound is vinyltrimethoxysilane or divinyl dimethoxysilane, general formula: R ¹ _x Si (O
R ² ) In _4-x , an organosilicon compound in which R ¹ is a vinyl group can be reliably realized. When the organosilicon compound is vinylsilane or divinylsilane, the general formula: R ¹ _x Si
An organic silicon compound in which R ¹ is a vinyl group in H _4-x can be reliably realized.

According to the second method for forming an interlayer insulating film, a carbon fluoride compound has two or more double bonds between carbon atoms in a molecule, and the carbon fluoride compound is decomposed by plasma. A radical having three or more dangling bonds is likely to be generated, and such a radical promotes a three-dimensional polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film is surely three-dimensional, so that the crosslink density is reliably increased and the glass transition point temperature is increased, so that the heat resistance is extremely improved.

In the second method for forming an interlayer insulating film, if the carbon fluoride compound consists of only carbon atoms and fluorine atoms,
Since hydrogen is not contained in the plasma polymerized film, the relative dielectric constant of the interlayer insulating film is reduced. In this case, when the carbon fluoride compound is hexafluoro-1,3-butadiene, a carbon fluoride compound having two or more double bonds between carbon atoms in a molecule and comprising only carbon atoms and fluorine atoms is used. Can be reliably realized.

According to the third method of forming an interlayer insulating film, a carbon fluoride compound has a triple bond between carbon atoms in a molecule. When the carbon fluoride compound is decomposed by plasma, unbonded bonds are generated. Are easily generated, and such radicals promote a three-dimensional polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film is surely three-dimensional, so that the crosslink density is reliably increased and the glass transition point temperature is increased, so that the heat resistance is extremely improved.

In the third method of forming an interlayer insulating film, when the carbon fluoride compound consists of only carbon atoms and fluorine atoms,
Since hydrogen is not contained in the plasma polymerized film, the relative dielectric constant is reduced. In this case, the carbon fluoride compound is hexafluoro-
When it is 2-butyne, a carbon fluoride compound having a triple bond between carbon atoms in the molecule and comprising only carbon atoms and fluorine atoms can be surely realized.

According to the fourth method for forming an interlayer insulating film, a carbon fluoride compound has a polycyclic structure in a molecule. When the carbon fluoride compound is decomposed by plasma, three dangling bonds are formed.
A radical having more than one is easily generated, and such a radical promotes a three-dimensional polymerization reaction. For this reason, the bonding of the polymers constituting the plasma polymerized film is surely three-dimensional, so that the crosslink density is reliably increased and the glass transition point temperature is increased, so that the heat resistance is extremely improved.

In the fourth method for forming an interlayer insulating film, when the carbon fluoride compound comprises only carbon atoms and fluorine atoms,
Since hydrogen is not contained in the plasma polymerized film, the relative dielectric constant is reduced.

In the fourth method for forming an interlayer insulating film, when the carbon fluoride compound has a condensed polycyclic structure in the molecule, a radical having three or more dangling bonds is more likely to be generated. The crosslink density is further increased, and the heat resistance is further improved. In this case, if the fluorocarbon compound is perfluorodecalin, perfluoroflorene or perfluorotetradecahydrophenanthrene, carbon fluoride having a condensed polycyclic structure in the molecule and consisting only of carbon and fluorine atoms The compound can be reliably realized.

According to the fifth method for forming an interlayer insulating film, a raw material containing an organic silicon compound and a carbon fluoride compound as main components is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to thereby form a silicon oxide containing carbon fluoride. Since a film is formed, it is not necessary to perform a step of applying a chemical solution of organic SOG and a step of curing, and thus the film is excellent in film forming properties. Further, since the raw material contains the carbon fluoride compound, the relative dielectric constant of the interlayer insulating film is reduced.

According to the sixth method of forming an interlayer insulating film, a raw material containing a mixed gas of an organic silicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to form a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. Further, as in the case of the second method for forming an interlayer insulating film, the carbon fluoride compound has two or more double bonds between carbon atoms in the molecule, and therefore has a high crosslinking density and excellent heat resistance. I have.

According to the seventh method for forming an interlayer insulating film, a raw material containing a mixed gas of an organic silicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent to form a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. In addition, as in the third method for forming an interlayer insulating film, the carbon fluoride compound has triple bonds between carbon atoms in the molecule, and therefore has a high crosslinking density and excellent heat resistance.

According to the eighth method for forming an interlayer insulating film, a raw material containing a mixed gas of an organic silicon compound and a carbon fluoride compound as a main component is subjected to a plasma polymerization reaction or to a reaction with an oxidizing agent, thereby forming a carbon fluoride. Since the containing silicon oxide film is formed, that is, it contains the organic silicon compound and the carbon fluoride compound, the relative dielectric constant is extremely low. Further, as in the fourth method for forming an interlayer insulating film, the carbon fluoride compound has a polycyclic structure in the molecule, and therefore has a high crosslinking density and excellent heat resistance.

In the sixth to eighth methods of forming an interlayer insulating film, the organosilicon compound is represented by the general formula: R ¹ _x Si (O
R ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to 3) or a siloxane derivative. In addition to the dielectric constant and heat resistance, the film forming property is also improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a plasma CVD apparatus used for a method of forming an interlayer insulating film according to each embodiment of the present invention.

FIGS. 2A to 2D are cross-sectional views illustrating steps of a first method for manufacturing a semiconductor device to which a method for forming an interlayer insulating film according to each embodiment of the present invention is applied.

FIGS. 3A to 3D are cross-sectional views illustrating respective steps of a second semiconductor device manufacturing method to which the method of forming an interlayer insulating film according to each embodiment of the present invention is applied.

FIG. 4 is a diagram showing analysis results when Fourier transform infrared spectroscopy is performed on the interlayer insulating film according to the first embodiment and the conventional organic SOG film.

FIG. 5 shows Fourier transform infrared spectroscopy when the interlayer insulating film according to the first embodiment is not subjected to the heat treatment, when the heat treatment is performed at 450 ° C., and when the heat treatment is performed at 500 ° C. It is a figure which shows the analysis result.

FIGS. 6A to 6D are cross-sectional views illustrating respective steps of a conventional method for forming an interlayer insulating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Reaction chamber 12 Semiconductor substrate 13 Sample stand 14 Changeover switch 15 1st high frequency power supply 16 Shower head 17 2nd high frequency power supply 21 1st gas supply line 22 2nd gas supply line 23 3rd gas supply line 24th 1st gas storage container 25 second gas storage container 26 vacuum pump 100 semiconductor substrate 101 first metal wiring 102 interlayer insulating film 103 contact 104 second metal wiring 200 semiconductor substrate 201 first layer silicon nitride film 202 first Layer interlayer insulating film 203 Second layer silicon nitride film 204 Second layer interlayer insulating film 205 Wiring pattern forming opening 206 Contact forming opening 207 Metal film 208 Metal wiring 209 Contact

Continuation of the front page (72) Inventor Kazuyuki Sawada 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References , A) JP-A-9-237783 (JP, A) JP-A-8-236519 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/312 H01L 21/314 H01L 21/316 H01L 21/318 H01L 21/3205 H01L 21/768 C23C 16/00-15/56

Claims (4)

(57) [Claims] An organic silicon compound and a carbon fluoride compound having two or more double bonds between carbon atoms in a molecule (provided that the compound is
And a raw material mainly containing a mixed gas with (excluding perfluorobenzene) a plasma polymerization reaction or a reaction with an oxidizing agent to form an interlayer insulating film made of a carbon fluoride-containing silicon oxide film. A method for forming an interlayer insulating film, comprising: 2. A plasma polymerization reaction or a reaction with an oxidizing agent of a raw material mainly containing a mixed gas of an organosilicon compound and a carbon fluoride compound having a triple bond between carbon atoms in a molecule. Forming an interlayer insulating film made of a silicon oxide film containing carbon fluoride. 3. A fluorinated material obtained by subjecting a raw material mainly containing a mixed gas of an organosilicon compound and a carbon fluoride compound comprising a compound having a polycyclic structure to a plasma polymerization reaction or a reaction with an oxidizing agent. A method for forming an interlayer insulating film, comprising forming an interlayer insulating film made of a carbon-containing silicon oxide film. 4. The organic silicon compound has a general formula: R
¹ _x Si (OR ² ) _4-x (where R ¹ is a phenyl group or a vinyl group, R ² is an alkyl group, and x is an integer of 1 to 3) or a siloxane derivative 4. The method according to claim 1, wherein
Item 14. The method for forming an interlayer insulating film according to Item 1.