JP7541466B2 - Composition for forming silicon-containing thin film and method for forming silicon-containing thin film - Google Patents

Description

The present invention relates to a composition for forming a silicon-containing thin film and a method for forming a silicon-containing thin film.

Silicon-containing thin films such as silicon nitride (SiN) films and silicon carbonitride films can form thin, chemically inactive passivation layers and are essential materials in the fabrication of semiconductor devices. For example, silicon nitride films are used as gate insulating films and sidewall spacers when forming thin-film transistors.

A typical method for manufacturing a silicon nitride film is to form the film at a film formation temperature of 600 to 750° C. by hot-wall low pressure chemical vapor deposition (LPCVD) using dichlorosilane (DCS) and ammonia (NH ₃ ). On the other hand, in a three-dimensional transistor such as a Fin-FET, it is required to change the channel material from silicon to silicon germanium and germanium, and due to the nature of the germanium, it is essential that the film formation temperature of the silicon nitride film after the channel formation is less than 500° C. However, in the conventional silicon nitride film formation technology, it is a fact that a silicon nitride film with good quality cannot be obtained at a film formation temperature of less than 500° C.

In recent years, as miniaturization and high integration progress and the horizontal and vertical dimensions of integrated circuits continue to shrink, there is a demand for thin-film formation technology that can control film thickness to the order of Å and has good coverage characteristics.

Silicon nitride films are generally manufactured by alternately supplying a silicon material source gas and a nitriding material reaction gas to a chamber. In the chamber, the source compound adsorbed on the substrate surface reacts with the nitriding reaction gas due to thermal energy to form a thin film. This method of forming a thin film by alternately supplying a source gas and a reaction gas is called atomic layer deposition (ALD).

The ALD method uses a plasma-assisted method in which reactive gases are supplied in a plasma-activated state. This plasma-assisted method has the advantage of being able to lower the deposition temperature when forming silicon-containing films, but it has major disadvantages, such as the unavoidable effect of damage on the underlying substrate and poor step coverage. For this reason, there is a demand for deposition processes that do not use plasma, and deposition materials and processes that allow the nitridation reaction to proceed even at low temperatures are being developed.

Non-Patent Document 1 and Patent Document 1 disclose a silicon nitride film formation technique at a film formation temperature of 400° C. or less using hexachlorodisilane (HCDS, Si ₂ Cl ₆ ) and ammonia (NH ₃ ).

On the other hand, aminosilane compounds such as bis-tertiary butyl aminosilane (BTBAS) are known as chlorine-free silicon materials.

JP 2002-343793 A

M. Tanaka et al. , J. Electrochem. Soc. 147,2284 (2000)

However, in the inventions described in Non-Patent Document 1 and Patent Document 1, when HCDS and NH ₃ are used, there is a problem that a rough film is formed because a large amount of chlorine derived from HCDS remains in the film at a film formation temperature of less than 500° C. Furthermore, it is known that ammonium salts, specifically ammonium chloride (NH ₄ Cl), are likely to be generated as by-products, which not only contaminate the substrate during the process but also cause blockage of the exhaust pipe.
Furthermore, aminosilane compounds are promising materials that do not generate ammonium chloride and do not leave chlorine remaining in the film, but they have the problem that silicon nitride films cannot be formed at film formation temperatures below 500°C.
As described above, in the formation of silicon-containing thin films using chemical vapor deposition, it has been impossible to obtain excellent silicon-containing thin films using conventional raw materials, and various requirements have not been fully met.

The present invention has been made in consideration of the above circumstances, and aims to provide a composition for forming a silicon-containing thin film and a method for forming a silicon-containing thin film that can form a high-quality silicon-containing thin film at a film formation temperature of less than 500°C using chemical vapor deposition and that produces a small amount of by-products.

ただし、式１１及び１３中、Ｒ１、Ｒ２およびＲ３は、それぞれ独立して選択される、炭素数１～５の直鎖または分枝の飽和アルキル基である。
また、式１１中、ｘおよびｙは、１≦ｘ＋ｙを満たし、０～２の中から選択される整数である。
［２］ 化学気相成長法によってシリコン含有薄膜を形成する、シリコン含有薄膜の形成方法であって、
シリコン含有原料として、［１］に記載のシリコン含有薄膜形成用組成物を用いる、シリコン含有薄膜の形成方法。
［３］ 処理室内の被処理基材の表面温度を所要の温度に制御し、前記処理室内の前記被処理基材に、前記シリコン含有原料を供給するステップと、
前記処理室内の前記被処理基材に、窒素含有原料を供給するステップと、を含む、［２］に記載のシリコン含有薄膜の形成方法。
［４］ 処理室内の被処理基材の表面温度を所要の温度に制御し、前記処理室内の前記被処理基材に、前記シリコン含有原料を供給するステップと、
前記シリコン含有原料の供給を停止するステップと、
前記処理室内の前記被処理基材に、窒素含有原料を供給するステップと、
前記窒素含有原料の供給を停止するステップと、を含むサイクルを繰り返す、［２］に記載のシリコン含有薄膜の形成方法。
［５］ 前記サイクルが、前記処理室内に残留する前記シリコン含有原料を前記処理室内から除去するステップをさらに含む、［４］に記載のシリコン含有薄膜の形成方法。
［６］ 前記サイクルが、前記処理室内に残留する前記窒素含有原料を前記処理室内から除去するステップをさらに含む、［４］又は［５］に記載のシリコン含有薄膜の形成方法。
［７］ 前記サイクルが、前記処理室内の前記被処理基材に、前記シリコン含有原料とは異なる他のシリコン含有原料を供給するステップをさらに含む、［４］乃至［６］のいずれかに記載のシリコン含有薄膜の形成方法。
［８］ 前記サイクルが、前記処理室内の前記被処理基材に、前記窒素含有原料とは異なる他の窒素含有原料を供給するステップをさらに含む、［４］乃至［７］のいずれかに記載のシリコン含有薄膜の形成方法。
［９］ 前記窒素含有原料が、アンモニア、ヒドラジン、モノメチルヒドラジン、ジメチルヒドラジン、ターシャリーブチルヒドラジン、ジメチルアミン、モノメチルアミン、及びターシャリーブチルアミンからなる群から選択される１つ以上の窒素含有化合物を含む、［３］乃至［８］のいずれかに記載のシリコン含有薄膜の形成方法。
［１０］ 前記シリコン含有薄膜は、シリコン窒化膜又はシリコン炭窒化膜である、［２］乃至［９］のいずれかに記載のシリコン含有薄膜の形成方法。
［１１］ 処理室内の被処理基材の表面温度を、５００℃未満の温度に制御する、［２］乃至［１０］のいずれかに記載のシリコン含有薄膜の形成方法。 In order to solve the above problems, the present invention has the following configuration.
[ 1 ] A composition for forming a silicon-containing thin film, which is used as a silicon-containing raw material when forming a silicon-containing thin film by chemical vapor deposition, comprising:
A composition for forming a silicon-containing thin film, comprising at least one selected from the group consisting of chloroaminodisilane compounds represented by the following formulas 11 and 13 :

In formulas 11 and 13 , R1, R2, and R3 are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms.
In addition, in formula 11 , x and y are integers selected from 0 to 2 and satisfy 1≦x+y.
[2] A method for forming a silicon-containing thin film by chemical vapor deposition, comprising:
A method for forming a silicon-containing thin film, comprising using the composition for forming a silicon-containing thin film according to [1] as a silicon-containing raw material.
[3] controlling a surface temperature of a substrate to be processed in a processing chamber to a required temperature, and supplying the silicon-containing raw material to the substrate to be processed in the processing chamber;
and supplying a nitrogen-containing source to the substrate in the processing chamber.
[4] controlling a surface temperature of a substrate to be processed in a processing chamber to a required temperature, and supplying the silicon-containing source material to the substrate to be processed in the processing chamber;
stopping the supply of the silicon-containing source material;
supplying a nitrogen-containing source to the substrate in the treatment chamber;
and stopping the supply of the nitrogen-containing source material.
[5] The method for forming a silicon-containing thin film according to [4], wherein the cycle further includes a step of removing the silicon-containing source material remaining in the processing chamber from the processing chamber.
[6] The method for forming a silicon-containing thin film according to [4] or [5], wherein the cycle further includes a step of removing the nitrogen-containing source remaining in the process chamber from the process chamber.
[7] The method for forming a silicon-containing thin film according to any one of [4] to [6], wherein the cycle further includes a step of supplying a silicon-containing source other than the silicon-containing source to the substrate to be processed in the processing chamber.
[8] The method for forming a silicon-containing thin film according to any one of [4] to [7], wherein the cycle further includes a step of supplying a nitrogen-containing source other than the nitrogen-containing source to the substrate to be processed in the processing chamber.
[9] The method for forming a silicon-containing thin film according to any one of [3] to [8], wherein the nitrogen-containing source contains one or more nitrogen-containing compounds selected from the group consisting of ammonia, hydrazine, monomethylhydrazine, dimethylhydrazine, tertiary butylhydrazine, dimethylamine, monomethylamine, and tertiary butylamine.
[10] The method for forming a silicon-containing thin film according to any one of [2] to [9], wherein the silicon-containing thin film is a silicon nitride film or a silicon carbonitride film.
[11] The method for forming a silicon-containing thin film according to any one of [2] to [10], wherein the surface temperature of the substrate to be treated in the treatment chamber is controlled to a temperature less than 500° C.

The composition for forming a silicon-containing thin film and the method for forming a silicon-containing thin film of the present invention can form a high-quality silicon-containing thin film at a film formation temperature of less than 500°C using chemical vapor deposition, and produces a small amount of by-products.

1 is a system diagram showing a schematic configuration of a film forming apparatus applicable to a method for forming a silicon-containing thin film of the present invention.

In this specification, the compound represented by formula 1 will be referred to as compound 1. Compounds represented by other formulas will be similarly referred to.
As used herein, the following terms have the following meanings:
The term "silicon-containing raw material" refers to a material containing a silicon-containing compound having two or more silicon atoms as a main component, specifically, 50% or more, preferably 90% or more. The silicon-containing raw material may contain two or more silicon-containing compounds within an appropriate range. The silicon-containing raw material may contain a crude raw material before purification, a by-product generated during synthesis of the silicon-containing compound, or a by-product generated during storage as impurities within an appropriate range.
The term "nitrogen-containing raw material" refers to a material mainly composed of a nitrogen-containing compound having one or more nitrogen atoms. The nitrogen-containing raw material may contain two or more nitrogen-containing compounds within an appropriate range. The nitrogen-containing raw material may contain raw materials before purification, by-products generated during synthesis of the nitrogen-containing compound, and by-products generated during storage as impurities within an appropriate range.
The term "silicon-containing thin film" refers to a film that contains Si atoms as a main component and has a Si content of 20 atm % or more. The silicon-containing thin film may also contain N atoms, O atoms, and C atoms within appropriate ranges.
The term "silicon nitride film" refers to a coating containing Si atoms and N atoms as main components. The silicon nitride film may also contain O atoms and/or C atoms within an appropriate range. Specifically, the silicon nitride film may contain 0 to 30 atm % of O atoms and 0 to 30 atm % of C atoms.
The term "silicon carbonitride film" refers to a film containing Si atoms, N atoms, and C atoms as main components. The silicon carbonitride film may contain O atoms within an appropriate range. Specifically, the silicon carbonitride film may contain 0 to 30 atm % of O atoms within the film.
The use of "to" indicating a range of numerical values means that the numerical values before and after it are included as the lower limit and upper limit.

<Silicon-containing thin film forming composition>
The present invention relates to a composition for forming a silicon-containing thin film (hereinafter, also referred to as "the composition") that is used as a silicon-containing raw material when forming a silicon-containing thin film by chemical vapor deposition.

(Chloroaminodisilane compound)
The present composition contains at least one type selected from the group consisting of chloroaminodisilane compounds represented by the following formula 1:
SiCl _a X _b H _c -SiCl _d Y _e H _fFormula 1

In formula 1, X and Y are NHR1 or NR2R3 alkylamino groups.

In addition, in formula 1, R1, R2, and R3 are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms. Linear or branched saturated alkyl groups having more than 5 carbon atoms, cyclic saturated alkyls, and cyclic unsaturated alkyl compounds are often solids, and even if they are liquids, they have low vapor pressures and are difficult to handle, such as by vaporization and supply, and are therefore not suitable for thin film-forming compositions.

[Straight-chain alkyl group]
The linear saturated alkyl groups having 1 to 5 carbon atoms are as follows:
Carbon number 1: "-CH ₃ "
Number of carbon atoms: 2: "-CH ₂ CH ₃ " (hereinafter, may be written as "-C ₂ H ₅ ").
Number of carbon atoms: 3: "-(CH ₂ ) ₂ CH ₃ " (hereinafter, also referred to as "-C ₃ H ₇ ").
Number of carbon atoms: 4: "-(CH ₂ ) ₃ CH ₃ " (hereinafter, also referred to as "-C ₄ H ₉ ").
Number of carbon atoms: 5: "-(CH ₂ ) ₄ CH ₃ " (hereinafter, also referred to as "-C ₅ H ₁₁ ").

[Branched Alkyl Group]
Examples of branched, saturated alkyl groups having 3 to 5 carbon atoms are as follows:
Carbon number 3: "-CH(CH ₃ ) ₂ "
- Number of carbon atoms: 4: “-CH ₂ CH (CH ₃ ) ₂ ”, “-CH (CH ₃ ) (C ₂ H ₅ )”, “-C (CH ₃ ) ₃ ”
- Carbon number 5: “-(CH ₂ ) ₂ CH(CH ₃ ) ₂ ”, “-CH ₂ CH(CH ₃ )CH ₂ CH ₃ ”, “-CH(CH ₃ )(CH ₂ ) ₂ CH ₃ ”, “-CH(CH ₃ )CH(CH ₃ ) ₂ ”, “-CH ₂ C(C H ₃ ) ₃ ”, “-C(CH ₃ ) ₂ (C ₂ H ₅ )”, “-CH(C ₂ H ₅ ) ₂ ”

Here, when a linear saturated alkyl group is selected as R1 in formula 1, polarization is generated in the intramolecular charge, and the effect of facilitating physical adsorption and chemical adsorption reactions on the substrate surface is obtained.
In addition, when a branched saturated alkyl group is selected as R1 in formula 1, the intramolecular charge is polarized in the same way as in the case of a linear saturated alkyl group, and thus the effect of facilitating the chemical adsorption reaction on the substrate surface is obtained. However, since the branched saturated alkyl group is a bulkier group than the linear saturated alkyl group, it has a structure that is more easily decomposed. Therefore, the branched saturated alkyl group is preferable in that the chemical adsorption reaction is more likely to occur at a lower temperature.

In this case, when linear saturated alkyl groups are selected as R2 and R3 in formula 1, polarization is generated in the intramolecular charge, and the effect of facilitating physical adsorption and chemical adsorption reactions on the substrate surface is obtained.
In addition, when branched saturated alkyl groups are selected as R2 and R3 in formula 2, the intramolecular charge is polarized in the same way as in the case of linear saturated alkyl groups, and the effect of facilitating chemical adsorption reaction on the substrate surface is obtained. However, since branched saturated alkyl groups are bulkier than linear saturated alkyl groups, they have a structure that is more easily decomposed. Therefore, branched saturated alkyl groups are preferable in that they facilitate chemical adsorption reaction at lower temperatures.

In addition, when a saturated alkyl group having a small number of carbon atoms is selected as R1 in formula 1, a compound having a high vapor pressure is obtained because the molecular structure has a smaller molecular weight than a saturated alkyl group having a large number of carbon atoms. Note that a material having a high vapor pressure is preferable to a material having a low vapor pressure in that handling such as vaporization is easier.
On the other hand, when a saturated alkyl group having a larger number of carbon atoms is selected as R1 in formula 1, the larger the number of carbon atoms in the saturated alkyl group, the higher the asymmetry between the H atom bonded to the N atom and R1, resulting in a structure that is easily decomposed and making it easier for a chemical adsorption reaction to occur at a lower temperature, which is preferable.

Furthermore, in formula 1, when saturated alkyl groups with a small number of carbon atoms are selected as R2 and R3, the resulting molecular structure has a smaller molecular weight than a saturated alkyl group with a large number of carbon atoms, and therefore a compound with a high vapor pressure can be obtained.
A material with a high vapor pressure is preferable since it is easier to handle, for example, by vaporizing and supplying the material than a material with a low vapor pressure.
On the other hand, when saturated alkyl groups having a large number of carbon atoms are selected as R2 and R3 in formula 1, the larger the number of carbon atoms, the bulkier the saturated alkyl group is, and the more easily the structure is decomposed, so that the chemical adsorption reaction is more likely to occur at a lower temperature.

In addition, when the same saturated alkyl group is selected as R2 and R3 in formula 1, the compound has high symmetry, so that the intramolecular charge is less biased and has good thermal stability.
On the other hand, when different saturated alkyl groups are selected as R2 and R3 in formula 1, the asymmetry becomes high, resulting in a structure that is easily decomposed, and the chemical adsorption reaction is likely to occur at a lower temperature.

From the viewpoint of forming a silicon-containing thin film, it is preferable to select a saturated alkyl group such as "-(CH ₂ ) ₂ CH ₃ " or "-CH(CH ₃ ) ₂ " as R1 in formula 1, which provides the effect of high vapor pressure, and it is more preferable to select a saturated alkyl group such as "-C(CH ₃ ) ₃ ", "-CH(CH 3 )(C ₂ H ₅ ) ", "-C(CH ₃ ) ₂ (C 2 H ₅ ) " or "-CH(C ₂ H ₅ ) ₂ ", which generates a more biased charge and is more likely to decompose and undergo a chemical adsorption reaction _at a low _temperature .

From the viewpoint of forming a silicon-containing thin film, it is preferable to select a saturated alkyl group such as "-(CH ₂ ) ₂ CH ₃ " or "-CH(CH ₃ ) ₂ " as R2 and R3 in formula 1, which provides a high vapor pressure effect, and it is more preferable to select a saturated alkyl group such as "-C(CH ₃ ) ₃ ", "-CH(CH ₃ )(C ₂ H ₅ ) ", "-C(CH ₃ ) ₂ (C 2 H 5 ) " or "-CH(C ₂ H ₅ ) ₂ ", which generates a more biased charge and is more likely to decompose and undergo a chemical adsorption reaction _at a low _temperature .

In addition, in formula 1, a, b, c, d, e and f are integers that satisfy the following five formulas (1) to (5).
(1) a+b+c=3
(2) d+e+f=3
(3) 1≦a+d≦4
(4) 1≦b+e≦5
(5) 0≦c+f≦4

Here, in formula 1, a and d indicate the number of "Si-Cl" bonds in the compound.
When the number of “Si—Cl” bonds in compound 1 is large (i.e., “a+d” in the above formula (3) is 3 or 4), the probability that the “Si—Cl” bonds collide with the substrate surface increases, resulting in an effect of making the adsorption reaction more likely to occur.
On the other hand, when the number of "Si-Cl" bonds in compound 1 is small (i.e., "a+d" in the above formula (3) is 1 or 2), the proportion of A (halogen atom) remaining in the film decreases, and an effect of forming a silicon-containing thin film with good film quality is obtained. Therefore, it is more preferable that the number of "Si-Cl" bonds is small.

In addition, in formula 1, b and e indicate the number of "Si-X, Y (alkylamino group)" bonds in the compound.
In compound 1, when the number of “Si—X, Y” bonds is large (that is, “b+e” shown in the above formula (4) is 4 or 5), the effect of improving the thermal stability of the compound is obtained.
On the other hand, when the number of “Si—X, Y” bonds in compound 1 is small (i.e., “b+e” shown in the above formula (4) is 1 or 2), there is less steric hindrance and the compound is more easily decomposed than when the number of “Si—X, Y” bonds is large, so that an effect is obtained in which the chemical adsorption reaction is more likely to occur at a lower temperature.

In addition, in formula 1, c and f indicate the number of "Si--H" bonds in the compound.
In compound 1, when the number of “Si—H” bonds is large (i.e., “c+f” shown in the above formula (5) is 3 or 4), the influence of steric hindrance of the molecule is alleviated, and thus the effect of making the chemisorption reaction more likely to occur at a lower temperature is obtained.
On the other hand, when the number of "Si-H" bonds in compound 1 is small (i.e., "c+f" in the above formula (5) is 0 or 1), the amount of hydrogen (H) in the film is reduced. However, from the viewpoint of forming a thin film at a lower temperature, it is preferable that the number of "Si-H" bonds is large.

When used to form a silicon-containing thin film, it is preferable to select the combination of (a+d=4, b+e=2, c+f=0) as a, b, c, d, e, and f in formula 1. In this case, the Cl (halogen) content in the silicon-containing thin film can be reduced, and the effect of the adsorption reaction on the substrate surface can be easily generated. Furthermore, when used to form a silicon-containing thin film, it is more preferable to select the combination of (a+d=2, b+e=2, c+f=2) as a, b, c, d, e, and f in formula 1. In this case, the Cl (halogen) content in the silicon-containing thin film can be reduced, and the effect of steric hindrance of the molecule is mitigated, so that the effect of chemical adsorption at a lower temperature can be easily obtained.

When compound 1 is used to form a silicon-containing thin film using chemical vapor deposition, it is preferable that the compound 1 is a chloroaminodisilane compound represented by the following formulas 11 to 14.

However, in compounds 11 to 14, R1, R2, and R3, like compound 1, are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms.
In compounds 11 and 12, x and y each represent an integer selected from 0 to 2 and satisfy 1≦x+y.

More preferably, compound 11 is a chloroaminodisilane compound represented by the following formulas 111 to 116.

More preferably, compounds 111 to 116 are chloroaminodisilane compounds in which x=y=1 or x=y=2.

More preferably, compound 12 is a chloroaminodisilane compound represented by the following formulas 121 to 126.

More preferably, compounds 121 to 126 are chloroaminodisilane compounds in which x = y = 1 or x = y = 2.

More preferably, compound 13 is a chloroaminodisilane compound represented by the following formulas 131 to 136.

More preferably, compound 14 is a chloroaminodisilane compound represented by the following formulas 141 to 146.

(Method of synthesizing chloroaminodisilane compound)
Next, a method for synthesizing compound 1 contained in the present composition will be described below.
Specifically, the cases of Compounds 11 and 12 will be described below as examples.

Compounds 11 and 12 are synthesized using a chlorodisilane compound and an amine compound as raw materials by the reaction shown in formula 2 or formula 3 below, respectively.

SiCl _(3-c) H _c -SiCl _(3-f) H _f +2(b+e)R1NH ₂ → SiCl _a (NHR1) _b H _c -SiCl _d (NHR1) _e H _f +(b+e)R1NH・HCl Formula 2

SiCl _(3-c) H _c -SiCl _(3-f) H _f +2(b+e)R2R3NH → SiCl _a (NR2R3) _b H _c -SiCl _d (NHR2R3) _e H _f +(b+e)R1NH・HCl Formula 3

In formula 2 and formula 3, R1, R2, and R3 are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms.
In addition, a, b, c, d, e, and f are integers that satisfy the five formulas: a+b+c=3, d+e+f=3, 1≦a+d≦4, 1≦b+e≦5, 0≦c+f≦4.

There is no particular limitation on the chlorodisilane compound used in the reaction shown in formula 2 or formula 3. Examples of such chlorodisilane compounds include hexachlorodisilane (Si ₂ Cl ₆ ) and tetrachlorodisilane (Si ₂ H ₂ Cl ₄ ).
As the chlorodisilane compound used in the reaction shown in formula 2 or formula 3, any one of the exemplified chlorodisilane compounds may be used, or a mixture of two or more of them may be used.

The amine compound used in the reaction shown in formula 2 is not particularly limited. Examples of such amine compounds include _R1NH2 . R1 is a linear or branched saturated alkyl group having 1 to 5 carbon atoms. Specific examples include _tBuNH2 , ( _CH3 ) _2CHNH2 , _CH3 ( _C2H4 ) _{NH2, CH3NH2, C2H5NH2, (CH3)2 (C2H5 ) CNH2 , ( C2H5 ) 2CHNH2 , and ( CH3 ) ( C2H5} ) _CHNH2 . As the amine compound, any one of the exemplified compounds may be used, or a mixture of _{two or more} of _them may be used.

The amine compound used in the reaction shown in formula 3 is not particularly limited. An example of such an amine compound is R2R3NH. Note that R2 and R3 are each independently a linear or branched saturated alkyl group having 1 to 5 carbon atoms. Specific examples include (( _CH3 ) _2CH ) _2NH , ( _CH3C2H4 ) _2NH , ( _CH3 ) _{2NH , ( C2H5 ) 2NH ,} CH3NHC2H5 _, (tBu _{) 2NH , tBuNHC2H5 , (} CH3 _{) 2CHNHC2H5 , CH3C2H4NHC2H5} , _tBuNHCH3 , ( _CH3 ) _{2CHNHCH3 , CH3C2H4NHCH3 , etc.} As the _amine compound, any one of the exemplified compounds may _be used, or a mixture of _two or more of _them may be used.

(Silicon-containing thin film forming composition)
The present composition contains one or more chloroaminodisilane compounds selected from the group consisting of chloroaminodisilane compounds represented by formula 1, and other components as required.

Specific examples of other components include other silicon materials containing one or more silicon atoms, such as DCS, BTBAS, and HCDS; nitrogen-containing compounds, such as ammonia ( _NH3 ), amine compounds, and hydrazine compounds; inert gases, such as helium (He), nitrogen ( _N2 ), argon (Ar), krypton (Kr), xenon (Xe), and neon (dNe); oxygen-containing compounds, such as oxygen ( _O2 ), water ( _H2O ), and ozone ( _O3 ); and hydrogen.

This composition contains 50% by mass or more of compound 1, preferably 90% by mass or more, and more preferably 99% by mass or more. When the content of compound 1 in this composition is 99% by mass or more, it is possible to suppress the local incorporation of impurities into the film, and it is possible to stabilize the film formation speed.

As explained above, the chloroaminodisilane compound (compound 1) shown in formula 1, in which R1, R2, and R3 are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms, is a silicon-containing compound that has a high vapor pressure and is liquid at room temperature and pressure. Therefore, this composition containing one or more types of compound 1 is useful as a silicon-containing raw material when forming a silicon-containing thin film by chemical vapor deposition.

<Film forming equipment>
Next, the configuration of a film forming apparatus applicable to the method for forming a silicon-containing thin film of the present invention will be described. Fig. 1 is a system diagram showing a schematic configuration of a film forming apparatus applicable to the method for forming a silicon-containing thin film of the present invention.
As shown in FIG. 1, the film forming apparatus 1 includes a processing chamber 2 which serves as a reaction site, a temperature control device 3 which controls the surface temperature of a substrate P to be processed in the processing chamber 2, a purge gas supply path L1 which supplies a purge gas to the processing chamber 2, an exhaust path L2 which exhausts the atmosphere in the processing chamber 2, a source gas supply path L3 which supplies a silicon-containing source gas, and a reaction gas supply path L4 which supplies a nitrogen-containing source gas.

The deposition apparatus 1 applicable to the silicon-containing thin film forming method of the present invention is not particularly limited as long as it is applicable to chemical vapor deposition. As the deposition apparatus 1, a CVD (Chemical Vapor Deposition) apparatus or an ALD (Atomic Layer Deposition) apparatus can be used.

The substrate P to be treated is not particularly limited as long as it is possible to form a silicon-containing thin film (hereinafter also simply referred to as a "thin film") on at least a portion of the surface. Examples of the substrate P to be treated include, but are not particularly limited to, semiconductor wafers, resins, and glass. Specifically, crystalline silicon (Si<100> or Si<111>, etc.), silicon oxide, strained silicon, SOI, silicon germanium, germanium, doped or undoped polysilicon, doped or undoped silicon wafers, silicon nitride, silicon carbide, silicon carbonitride, silicon oxynitride, silicon carbonate, silicon carbonate nitride, metals such as Cu, Al, Ru, Ta, W, Ti, Co, Zr, and Hf, metal nitrides such as TiN, TaN, and WN, metal oxides such as ZrO, HfO, TiO, TaO, and WO, patterned or unpatterned wafers, and semiconductor wafers containing at least one of the above can be used. Resins such as polyethylene, polypropylene, polyolefin resins, polyvinyl chloride resins, fluorine resins, and polyester resins can also be used.

The silicon-containing thin film is not particularly limited as long as it contains silicon. As the silicon-containing thin film, a silicon nitride film, a silicon carbonitride film, a silicon oxide film, a silicon oxynitride film, a silicon film, and a silicon oxycarbonitride film are preferable, a silicon nitride film and a silicon carbonitride film are more preferable, and a silicon nitride film is even more preferable.

The temperature control device 3 is not particularly limited as long as it can control the surface temperature of the substrate P to be treated in the treatment chamber 2 to the required temperature. A heater and its control device can be used as the temperature control device 3.

The temperature control device 3 can control the surface temperature of the substrate P to be treated in the treatment chamber 2 to less than 500°C, and it is more preferable to control it to less than 450°C.

The purge gas supply path L 1 supplies a purge gas into the processing chamber 2 .
The purge gas is not particularly limited, but may be one or more of rare gases such as helium (He) and argon (Ar), nitrogen (N ₂ ), and hydrogen (H ₂ ).

The exhaust path L2 exhausts the atmospheric gas, including the purge gas, the raw material gas, and the reaction gas, from the processing chamber 2, thereby reducing the pressure inside the processing chamber 2. A pressure reducing device 4, such as a pressure reducing pump, is disposed in the exhaust path L2.

The raw material gas supply path L3 supplies a silicon-containing raw material containing a silicon-containing compound as a raw material gas into the processing chamber 2 via the purge gas supply path L1. The raw material gas supply path L3 is provided with a raw material container 5 for storing liquid silicon-containing raw material, a vaporizer 6, and a carrier gas heater 7.

The method of supplying the silicon-containing raw material is not particularly limited. The silicon-containing raw material can be supplied by vaporizing the liquid silicon-containing raw material (silicon-containing thin film forming composition) from the liquid phase 5A of the raw material container 5 using the vaporizer 6. Also, the vapor of the silicon-containing raw material can be supplied from the gas phase 5B of the raw material container 5 without using the vaporizer 6. The silicon-containing raw material may be supplied into the processing chamber 2 together with a carrier gas such as an inert gas.

In addition, the inside of the source container 5 may be bubbled with a carrier gas to supply vapor of the silicon-containing source material together with the carrier gas into the processing chamber 2.

When supplying the silicon-containing raw material, the raw material container 5 may be appropriately heated to increase the vapor pressure of the silicon-containing raw material before supplying it.

The silicon-containing thin film forming composition of the present invention can be used as the silicon-containing raw material.

The carrier gas is not particularly limited, but may be one or more of rare gases such as helium (He) and argon (Ar), nitrogen (N ₂ ), and hydrogen (H ₂ ).

The reaction gas supply path L4 supplies a nitrogen-containing raw material as a reaction gas into the processing chamber 2 via the purge gas supply path L1. The nitrogen-containing raw material may be supplied into the processing chamber 2 together with a carrier gas such as an inert gas.

The nitrogen-containing feedstock comprises one or more nitrogen-containing compounds.
Examples of the nitrogen-containing compound that can be used include ammonia, hydrazine, monomethylhydrazine, dimethylhydrazine, tertiary butylhydrazine, dimethylamine, monomethylamine, and tertiary butylamine.

The carrier gas is not particularly limited, but may be one or more of rare gases such as helium (He) and argon (Ar), nitrogen (N ₂ ), and hydrogen (H ₂ ).

The configuration of the film forming apparatus 1 applicable to the present invention is an example, and is not limited thereto. For example, the raw material gas supply path L3 may be configured to have multiple branch paths in order to supply multiple types of silicon-containing compounds as silicon-containing raw materials into the processing chamber 2. In addition, the reaction gas supply path L4 may be configured to have multiple branch paths in order to supply multiple types of nitrogen-containing compounds as nitrogen-containing raw materials into the processing chamber 2.

Method for forming silicon-containing thin film
The method for forming a silicon-containing thin film of the present invention is a method for forming a silicon-containing thin film by chemical vapor deposition using the composition for forming a silicon-containing thin film of the present invention as a silicon-containing raw material.

Chemical vapor deposition methods include, but are not limited to, CVD, plasma CVD, ALD, and plasma ALD. Among these, CVD and ALD are preferred, and ALD is more preferred.

As described above, silicon-containing thin films are preferably silicon nitride film, silicon carbonitride film, silicon oxide film, silicon oxynitride film, silicon film, and silicon oxycarbonitride film, more preferably silicon nitride film and silicon carbonitride film, and even more preferably silicon nitride film.

The following methods 1 to 4 are specifically described as methods for forming a silicon-containing thin film using the above-described film formation apparatus 1.

(Method 1)
First, the surface temperature of the substrate (substrate to be processed) P transferred into the processing chamber 2 is controlled to a required temperature. Specifically, the surface temperature of the substrate P is controlled to less than 500° C. using the temperature control device 3. The controlled temperature is more preferably 450° C. or less.

Next, perform the following steps:
Step A: A source gas containing a silicon-containing compound is supplied to the substrate P in the processing chamber 2 .
Step B: A reaction gas containing a nitrogen-containing compound is supplied to the substrate P in the processing chamber 2 .

In step A, a composition for forming a silicon-containing thin film containing one or more chloroaminodisilane compounds selected from the group consisting of the above-mentioned compound 1 is used as a source gas.
The source gas may contain the above-mentioned carrier gas as a coexisting gas in addition to the silicon-containing thin film-forming composition.

In step B, a nitrogen-containing source containing one or more nitrogen-containing compounds selected from the group consisting of the above-mentioned nitrogen-containing compounds is used as a reaction gas.
The reaction gas may contain the above-mentioned carrier gas as a coexisting gas in addition to the nitrogen-containing raw material.

In method 1, steps A and B are performed until the thin film on the substrate P reaches the required thickness. Steps A and B may be performed simultaneously (CVD method) or alternately (ALD method).

(Method 2)
Method 2 is a method for forming a silicon nitride film by the ALD method.
First, similarly to method 1, the surface temperature of the substrate P transferred into the processing chamber 2 is controlled to a required temperature.

A cycle is then performed which includes the following steps:
Step A: A source gas containing a silicon-containing compound is supplied to the substrate P in the processing chamber 2 .
Step B: The supply of the source gas is stopped, and the source gas remaining in the processing chamber 2 is removed.
Step C: A reactive gas containing a nitrogen-containing compound is supplied to the substrate P in the processing chamber 2 .
Step D: The supply of the reaction gas is stopped, and the reaction gas remaining in the processing chamber 2 is removed.

In step A, a source gas is supplied under vacuum to the substrate P in the processing chamber 2. The source gas may be the same as that shown in step A of the method 1 described above. This causes a chemical adsorption reaction between the surface of the substrate P and the chloroaminodisilane compound.

In step B, the supply of the source gas is stopped after the above-mentioned chemical adsorption reaction, and purging is performed to remove any unreacted chloroaminodisilane compound remaining in the processing chamber 2.

In step C, a reactive gas is supplied under vacuum to the substrate P in the processing chamber 2. The reactive gas shown in step B of the above-mentioned method 1 can be used as the reactive gas. This causes the chloroaminodisilane compound adsorbed on the surface of the substrate P in step A to be nitrided.

In step D, after the nitridation reaction of the chloroaminodisilane compound described above, the supply of the reaction gas is stopped, and purging is performed to remove any unreacted nitrogen-containing compound remaining in the processing chamber 2.

In step B and step 2D, an inert gas such as helium (He), nitrogen (N ₂ ), or argon (Ar) can be used as a purge gas.

In method 2, the above-described cycle is repeated multiple times (e.g., 300 cycles) to form a silicon nitride film of the desired thickness on the substrate P.

In method 2, steps A to D are performed in this order in the cycle described above, but the next step may be started after the previous step is completed, or before the previous step is completed, or steps B and D may be omitted. In this way, by overlapping some steps or omitting some steps, the time per cycle can be shortened. Furthermore, the film formation speed can be controlled to the required speed.

(Method 3)
First, similarly to method 1, the surface temperature of the substrate P transferred into the processing chamber 2 is controlled to a required temperature.

A cycle including the following steps is then repeated multiple times.
Step A: A first source gas containing a silicon-containing compound is supplied into the processing chamber 2 .
Step B: The supply of the first source gas is stopped, and the remaining first source gas is removed.
Step C: A first reaction gas containing a nitrogen-containing compound is supplied into the processing chamber 2 .
Step D: The supply of the first reaction gas is stopped, and the remaining first reaction gas is removed.
Step C-2: A second reactive gas different from the first reactive gas is supplied into the processing chamber 2.
Step D-2: The supply of the second reaction gas is stopped, and the remaining second reaction gas is removed.

(Method 4)
First, similarly to method 1, the surface temperature of the substrate P transferred into the processing chamber 2 is controlled to a required temperature.

A cycle including the following steps is then repeated multiple times.
Step A: A first source gas containing a silicon-containing compound is supplied into the processing chamber 2 .
Step B: The supply of the first source gas is stopped, and the remaining first source gas is removed.
Step A-2: A second source gas different from the first source gas is supplied into the processing chamber 2.
Step B-2: The supply of the second source gas is stopped, and the remaining second source gas is removed.
Step C: A first reaction gas containing a nitrogen-containing compound is supplied into the processing chamber 2 .
Step D: The supply of the first reaction gas is stopped, and the remaining first reaction gas is removed.

In methods 3 and 4, the raw material gas shown in step A of method 1 described above can be used as the first raw material gas. Also, the reactive gas shown in step B of method 1 described above can be used as the first reactive gas.

In method 3, a nitrogen-containing raw material containing one or more nitrogen-containing compounds different from the nitrogen-containing raw material used in the first reaction gas is used as the second reaction gas. By using this method, it is possible to form a film while modifying the surface, i.e., it is possible to form a denser film.

The nitrogen-containing compound used as the nitrogen-containing raw material of the second reactive gas may be selected from the group consisting of ammonia, hydrazine, monomethylhydrazine, dimethylhydrazine, tertiary butylhydrazine, dimethylamine, monomethylamine, and tertiary butylamine described above, or may be selected from a group other than these. The second reactive gas may contain coexisting gases in addition to the nitrogen-containing compound, as in the first reactive gas.

In method 4, a silicon-containing raw material containing one or more silicon-containing compounds different from the chloroaminodisilane compound used as the silicon-containing raw material of the first raw material gas is used as the second raw material gas. By using this method, it is possible to form a film while modifying the surface, that is, it is possible to form a denser film.

The silicon-containing compound used as the silicon-containing raw material of the second raw material gas may be selected from the group consisting of the above-mentioned compound 1, or may be selected from compounds other than compound 1. For example, silicon-containing compounds used in conventional silicon-containing thin film formation, such as DCS, HCDS, BTBAS, SiHCl ₃ , SiCl ₄ , SiH ₃ Cl, other alkylaminosilanes, alkylsilanes, and other chlorosilane compounds, may be used.

The second source gas, like the first source gas, may contain coexisting gases in addition to the silicon-containing compound.

When the ALD method is applied as a method for forming a silicon-containing thin film of the present invention, the film may be formed by a two-step reaction including one step of supplying a source gas (hereinafter also referred to as the "first step") and one step of supplying a reactant gas (hereinafter also referred to as the "second step") in one cycle, as shown in the above method 2, or by a three-step or more reaction including two or more of either or both of the first step and the second step in one cycle, as shown in the above methods 3 and 4.

The method for forming a silicon-containing thin film of the present invention uses the composition for forming a silicon-containing thin film of the present invention (i.e., contains any one or more chloroaminodisilane compounds selected from the group consisting of chloroaminodisilane compounds represented by formula 1) in at least the first step when forming a thin film by a two-step reaction or a three-step or more reaction, so that a high-quality silicon-containing thin film can be formed.

In addition, in the method for forming a silicon-containing thin film of the present invention, a thin film can be formed while modifying the substrate surface structure by forming the film by a reaction of three or more steps. For example, when ammonia is used in the second step in method 3, it is possible to compensate for the reaction sites where the nitriding reaction is insufficient by using hydrazine in the third step. When only hydrazine is used, a rough film may be formed due to the remaining N-N bonds. Similarly, for example, when a chloroaminodisilane compound is used in the first step in method 4, it is possible to reach the reaction sites where the adsorption reaction is insufficient by using dichlorosilane, which has a smaller molecular size, in the second step, and it is possible to compensate for the adsorption reaction. For the above reasons, by using a three-step reaction, the proportion of Si or N can be increased compared to general film formation by a two-step reaction, and in some cases a denser and better silicon-containing thin film can be formed.

Note that methods 1 to 4 are merely examples of the method of forming a silicon-containing thin film of the present invention, and are not limited to these. For example, the chloroaminodisilane compound and the nitrogen-containing compound may be supplied by various methods other than the above methods 1 to 4.

<Method for evaluating silicon-containing thin films>
The thin film obtained by the method for forming a silicon-containing thin film of the present invention can be evaluated for film quality, film formation amount, and film denseness by the following methods.

(Evaluation of film quality)
The quality of the thin film can be evaluated from the measured film thickness and refractive index using a commercially available spectroscopic ellipsometer (for example, a spectroscopic ellipsometer "GES5E" manufactured by SOPRA Corporation).

For example, if the silicon-containing thin film is a silicon nitride film, a refractive index within the range of 1.8 to 2.1 can generally be evaluated as a good quality silicon nitride film.

On the other hand, when the refractive index is less than 1.8, the silicon nitride film can be evaluated as having a coarse film structure. Note that the smaller the refractive index, the more oxygen components are mixed into the film.

Also, when the refractive index is 1.6 or less, it generally exhibits the properties of a silicon oxide film or a silicon oxynitride film.

When the refractive index exceeds 1.8, the film may contain carbon components, and the higher the carbon content, the higher the refractive index tends to be.

(Amount of film formed)
From the obtained film thickness, the growth per cycle (GPC), which is the amount of film formed per cycle, can be calculated.

(Film Density)
The denseness of the film can be evaluated from the results of infrared absorption spectrum measurement using a commercially available Fourier transform infrared spectrophotometer (FT-IR; for example, PerkinElmer's Fourier infrared spectrophotometer device, "Spectrum 400", etc.).

Infrared absorption spectrum measurement generally shows that vibrations derived from "Si-N" bonds are observed around 800 to 900 cm ^-1 , and vibrations derived from "Si-O" bonds are observed around 1000 to 1100 cm ^-1 . The denseness of the film can be evaluated by not observing vibrations derived from "Si-O" bonds and by measuring the intensity of SiN.

Incidentally, when a silicon-containing thin film is formed using hexachlorodisilane ( _HCDS , _Si2Cl6 ), which is a known material as a silicon-containing compound, and ammonia ( _NH3 ) as a nitrogen-containing compound, at a film formation temperature of less than 500°C, a large amount of chlorine derived from HCDS remains in the film, resulting in the formation of a rough film.
The reasons for this are explained below.

When HCDS and _NH3 are used as the silicon-containing compound and the nitrogen-containing compound, a thin film is formed by the following reactions in both the chemical adsorption reaction in the first step (hereinafter also referred to as the "first reaction") and the nitridation reaction in the second step (hereinafter also referred to as the "second reaction").
In the following, ΔHf represents the heat of reaction and ΔEa represents the activation energy of the reaction.

(First reaction)
=NH (substrate surface) +Si ₂ Cl ₆ → =N-Si ₂ Cl ₅ +HCl
ΔHf=+18kJ/mol, ΔEa=57kJ/mol

(Second reaction)
=N-Si ₂ Cl ₅ +5NH ₃ → =N-Si ₂ (NH ₂ ) ₅ +5HCl
ΔHf=+105kJ/mol, ΔEa=65kJ/mol

The first and second reactions are both endothermic reactions, and these endothermic reactions are repeated until the film thickness reaches the specified value.

On the other hand, hydrogen chloride (HCl) produced as a by-product during the first and second reactions may react with the substrate surface to which HCDS is adsorbed (first reaction) and with the substrate surface to which _NH3 is nitrided (second reaction) as shown below.

(First reaction)
=N-Si ₂ Cl ₅ +HCl → =N-H+Si ₂ Cl ₆
ΔHf=-18kJ/mol, ΔEa=39kJ/mol

(Second reaction)
=N-Si ₂ (NH ₂ ) ₅ +HCl → =N-Si ₂ Cl(NH ₂ ) ₄ +NH ₃
ΔHf=-44kJ/mol, ΔEa=56kJ/mol

The activation energy ΔEa of the first' and second' reactions is not only lower than the activation energy of the first and second reactions, but also indicates an exothermic reaction.
Therefore, when the HCl by-product produced during the first and second reactions collides with the substrate surface, the first and second reactions proceed easily, resulting in the formation of a rough film with residual chlorine in the formed film.

In particular, at film formation temperatures below 500°C, the first and second reactions are endothermic, and the reaction between the by-product HCl and the substrate surface occurs significantly.

In addition, because the second reaction is a large endothermic reaction, if the thermal energy is low, less than 500°C, the nitriding reaction may not proceed completely. This causes chlorine to remain in the film, which is one of the factors that leads to the formation of a rough film.

On the other hand, aminosilane compounds such as bis-tertiary butyl aminosilane (BTBAS) do not contain Si-Cl bonds, so no chlorine remains in the film. However, because aminosilane compounds have a high activation energy (ΔEa = 130 kJ/mol) for the chemical adsorption reaction with the substrate surface, they cannot form thin films at film formation temperatures below 500°C.

Compared to the known silicon-containing compounds such as HCDS and BTBAS mentioned above, the chloroaminodisilane compound represented by formula 1 contained in the composition for forming a silicon-containing thin film of the present invention has good adsorption characteristics to the substrate surface and does not cause a large endothermic reaction, so that a high-quality silicon nitride film can be formed even at a film formation temperature of less than 500°C.

For example, when the chloroaminodisilane compound contained in the silicon-containing thin film forming composition of the present invention is "Si ₂ H ₂ Cl ₂ (NHtBu) ₂ (compound 111)", the first reaction has ΔHf = +15 kJ/mol, ΔEa = 85 kJ/mol, and the second reaction has ΔHf = -15 kJ/mol, ΔEa = 120 kJ/mol. Since the first reaction has the same reaction energy as HCDS/NH ₃ and the second reaction is an exothermic reaction, it is suggested that compound 111 of the present invention is promising as a silicon-containing compound for forming a silicon-containing thin film.

The alkylamino groups (hereinafter sometimes simply referred to as "substituents") contained in compounds 11 to 14 of the present invention all exhibit an exothermic reaction in the second reaction described above, and therefore are prone to nitridation reactions.

Of the compounds 11 to 14 of the present invention, compounds 111 to 113 and compounds 121 to 123, 131 to 133, and 141 to 143 have high vapor pressure and excellent material supply, and are therefore preferred as silicon-containing compounds for forming silicon-containing thin films.

Furthermore, the chloroaminodisilane compound (compound 1) represented by the above formula 1 produces less HCl per mole than HCDS. Therefore, the composition for forming a silicon-containing thin film of the present invention produces less by-products such as NH ₄ Cl, which can cause pipe clogging, and is therefore useful as a silicon-containing compound for forming a silicon-containing thin film.

Furthermore, among compounds 11 and 12, chloroaminodisilane compounds containing one or two Si-Cl bonds are more preferable as silicon-containing compounds for forming silicon-containing thin films because they produce a smaller amount of HCl per mole.

As described above, the silicon-containing thin film forming composition of the present invention and the method for forming a silicon-containing thin film using the composition as a silicon-containing raw material make it possible to form a high-quality silicon-containing thin film at a film formation temperature of less than 500°C by chemical vapor deposition, and produce a small amount of by-products.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

<Synthesis of chloroaminodisilane compound>
In forming the silicon nitride films of Examples 1 to 36 described later, the chloroaminodisilane compound contained in the silicon-containing thin film forming composition used as the silicon-containing raw material was synthesized by the following procedure.
The synthesized chloroaminodisilane compounds were identified by the following method.

[NMR Measurement]
The NMR measurement was carried out using a nuclear magnetic resonance apparatus (manufactured by JEOL Ltd., "JNM-ECS400") A deuterated benzene solution was used for sample preparation.

[GC analysis]
The GC analysis was carried out using a gas chromatograph (Shimadzu Corporation, "GC-2014"). An FID was used as the detector. The target product and its purity were confirmed based on the retention time.

(Synthesis Example 1)
Synthesis of "Si ₂ H ₂ Cl ₂ (NHtBu) ₂ " In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ H ₂ Cl ₄ (20.35 g, 0.102 mol, CAS No.: 20536-16-7) were added to a flask.
To this well-stirred solution, tBuNH ₂ (29.77 g, 0.41 mol, CAS No.: 13465-77-5) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 6.40 g of the target product, Si ₂ H ₂ Cl ₂ (NHtBu) _2. The yield was 23%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 19 min and 88%, respectively.

(Synthesis Example 2)
Synthesis of "Si ₂ Cl ₂ (NHtBu) ₄ " (Compound 111) In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ Cl ₆ (24.79 g, 0.0922 mol, CAS No.: 13465-77-5) were added to a flask.
To this well-stirred solution, (tBu) ₂ NH ₂ (42.12 g, 0.738 mol) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 9.58 g of the target product, Si ₂ Cl ₂ (NHtBu) _4. The yield was 25%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 19 min and 69%, respectively.

(Synthesis Example 3)
Synthesis of "Si ₂ H ₂ Cl ₂ (NtBu ₂ ) ₂ " (Compound 122) In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ H ₂ Cl ₄ (20.12 g, 0.100 mol, CAS No.: 20536-16-7) were added to a flask.
To this well-stirred solution, (tBu) ₂ NH (52.01 g, 0.402 mol) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 8.53 g of the target product, Si ₂ H ₂ Cl ₂ (NtBu2) _2. The yield was 22%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 19 min and 82%, respectively.

(Synthesis Example 4)
Synthesis of "Si ₂ Cl ₂ (NtBu ₂ ) ₄ " (Compound 122) In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ H ₂ Cl ₄ (20.22 g, 0.075 mol, CAS No.: 20536-16-7) were added to a flask.
To this well-stirred solution, (tBu) ₂ NH (77.75 g, 0.602 mol) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 9.63 g of the target product, Si ₂ Cl ₂ (N(C(CH ₃ ) ₃ ) ₂ ) _4. The yield was 20%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 21 min and 81%, respectively.

(Synthesis Example 5)
Synthesis of "Si ₂ Cl ₄ (NHtBu) ₂ " (Compound 131) In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ Cl ₆ (25.16 g, 0.094 mol, CAS No.: 13465-77-5) were added to a flask.
To this well-stirred solution, tBuNH ₂ (27.44 g, 0.38 mol) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 7.29 g of the target product, Si ₂ Cl ₄ (NHtBu) _2. The yield was 23%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 19 min and 60%, respectively.

(Synthesis Example 6)
Synthesis of "Si ₂ Cl ₄ (NtBu ₂ ) ₂ " (Compound 141) In a reaction vessel cooled to -70°C, 900 mL of diethyl ether and Si ₂ Cl ₆ (25.23 g, 0.094 mol) were added to a flask.
To this well-stirred solution, (tBu) ₂ NH (48.51 g, 0.375 mol) dissolved in 100 mL of diethyl ether was slowly added dropwise, and the temperature was gradually raised to room temperature, followed by stirring for 8 hours.
After distilling off diethyl ether under reduced pressure, 1000 mL of hexane was added for extraction, and the amine hydrochloride was removed by filtration.
Thereafter, recrystallization was carried out at −30° C., and the remaining hexane was distilled off to obtain 9.38 g of the target product, Si ₂ Cl ₄ (N(C(CH ₃ ) ₃ ) ₂ ) _2. The yield was 22%.
The target product was confirmed by NMR and GC analysis. The retention time and purity of the target product in GC were 20 min and 64%, respectively.

<Formation of Silicon Nitride Film>
Using the film forming apparatus 1 shown in FIG. 1, silicon nitride films of Comparative Examples 1 to 3 and Examples 1 to 46 were formed (deposited) by the ALD method using the raw materials and film forming conditions shown in Tables 1 to 3 below.
The formed silicon nitride film was measured and evaluated by the following methods, and the results are shown in Tables 1 to 3 below.

(Measurement and evaluation methods)
[Film thickness]
The measurements were made using spectroscopic ellipsometry.

[Refractive index]
The measurements were made using spectroscopic ellipsometry.

[Infrared absorption spectrum]
The infrared absorption spectrum was measured using a Fourier transform infrared spectrophotometer under the conditions of a detector: TGS and a resolution: 4 cm ^-1 .

[Evaluation of film quality]
When the measured refractive index was within the range of 1.8 to 2.1, the silicon nitride film was evaluated as being of good quality.
On the other hand, when the measured refractive index was less than 1.8, the silicon nitride film was evaluated to have a coarse film structure.

[Film formation amount]
From the measured film thickness, the growth per cycle (GPC), which is the amount of film formed per cycle, was calculated.

[Film density]
From the results of the measured infrared absorption spectrum, vibrations derived from "Si--O" bonds in the vicinity of 1000 to 1100 cm ^-1 and vibrations derived from "Si--N" bonds in the vicinity of 800 to 900 cm ^-1 were confirmed.
In addition, the Si--N peak intensity ratios of Examples 1 to 43 to Comparative Example 1 were calculated using the peak intensities derived from the "Si--N" bond obtained from the infrared absorption spectrum, and the denseness of the film was evaluated.

(Comparative Example 1)
[Film formation conditions]
Film formation temperature (substrate surface temperature): 450°C
Silicon-containing compound: hexachlorodisilane (HCDS)
Nitrogen-containing compounds: ammonia ( _NH3 )
Number of cycles repeated: 300 times

[cycle]
Step 1: A silicon-containing compound is supplied into the processing chamber for 10 seconds and allowed to adsorb onto the substrate surface.
Step 2: Purge with _N2 for 10 seconds to remove unreacted silicon-containing compounds.
Step 3: A nitrogen-containing compound is supplied into the processing chamber for 10 seconds to nitride the substrate surface.
Step 4: Purge with _N2 for 10 seconds to remove unreacted nitrogen-containing compounds.

[Evaluation Results]
・GPC: 0.10 (Å/cycle)
Refractive index: 1.48
・FT-IR:
In addition to Si--N vibrations, Si--O vibrations were observed.
Measurement of the sample after several days showed a decrease in the Si-N peak intensity and an increase in the Si-O peak intensity, indicating the formation of a rough silicon nitride film and further changes over time.

(Comparative Example 2)
[Film formation conditions]
A silicon nitride film was formed under the same film formation conditions as in Comparative Example 1, except that bis-tertiarybutylaminosilane (BTBAS) was used instead of HCDS as the silicon-containing compound.

[Evaluation Results]
In Comparative Example 2, a thin film was not formed, and a silicon nitride film could not be obtained.

(Comparative Example 3)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that chlorodiisopropylaminosilane was used instead of HCDS as the silicon-containing compound.

[Evaluation Results]
・GPC: 0.11 (Å/cycle)
Refractive index: 1.68
In addition to Si--N vibration, Si--O vibration was observed.
Measurement of the sample after several days showed a decrease in the Si-N peak intensity and an increase in the Si-O peak intensity, indicating the formation of a rough silicon nitride film and further indicating changes over time.

(Example 1)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.40 (Å/cycle)
Refractive index: 2.02
Si-N peak intensity ratio at a film thickness of 30 nm (Example 1/Comparative Example 1): 1.85
The silicon nitride film of Example 1 had a Si—N peak intensity ratio of 1.85, and it was confirmed that the denseness of the silicon nitride film was improved compared to Comparative Example 1.

(Example 2)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₄ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.23 (Å/cycle)
Refractive index: 1.90
Si-N peak intensity ratio at a film thickness of 30 nm (Example 2/Comparative Example 1): 1.63
The silicon nitride film of Example 2 had a Si—N peak intensity ratio of 1.71, and it was confirmed that the denseness of the silicon nitride film was improved compared to Comparative Example 1.

(Example 3)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NHCH(CH ₃ ) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.42 (Å/cycle)
Refractive index: 2.05
Si-N peak intensity ratio at a film thickness of 30 nm (Example 3/Comparative Example 1): 1.90
The silicon nitride film of Example 3 had a Si—N peak intensity ratio of 1.90, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 4)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NHCH(CH ₃ ) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.36 (Å/cycle)
Refractive index: 1.94
Si—N peak intensity ratio at a film thickness of 30 nm (Example 4/Comparative Example 1): 1.66
The silicon nitride film of Example 4 had a Si—N peak intensity ratio of 1.66, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 5)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NH(CH ₂ ) ₂ (CH ₃ )) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.39 (Å/cycle)
Refractive index: 2.04
Si—N peak intensity ratio at a film thickness of 30 nm (Example 5/Comparative Example 1): 1.88
The silicon nitride film of Example 5 had a Si—N peak intensity ratio of 1.88, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 6)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NH(CH ₂ ) ₂ (CH ₃ )) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.23 (Å/cycle)
Refractive index: 1.93
Si—N peak intensity ratio at a film thickness of 30 nm (Example 6/Comparative Example 1): 1.68
The silicon nitride film of Example 6 had a Si—N peak intensity ratio of 1.68, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 7)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₂ (C ₂ H ₅ )) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.36 (Å/cycle)
Refractive index: 1.94
Si—N peak intensity ratio at a film thickness of 30 nm (Example 7/Comparative Example 1): 1.70
The silicon nitride film of Example 7 had a Si—N peak intensity ratio of 1.70, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Example 1.

(Example 8)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NHC(CH ₃ ) ₂ (C ₂ H ₅ )) ₄ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.21 (Å/cycle)
Refractive index: 1.86
Si—N peak intensity ratio at a film thickness of 30 nm (Example 8/Comparative Example 1): 1.55
The silicon nitride film of Example 8 had a Si—N peak intensity ratio of 1.55, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 9)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NHCH(CH ₃ )(C ₂ H ₅ )) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.42 (Å/cycle)
Refractive index: 2.02
Si—N peak intensity ratio at a film thickness of 30 nm (Example 9/Comparative Example 1): 1.85
The silicon nitride film of Example 9 had a Si—N peak intensity ratio of 1.85, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 10)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NHCH(CH ₃ )(C ₂ H ₅ )) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.22 (Å/cycle)
Refractive index: 1.90
Si-N peak intensity ratio at a film thickness of 30 nm (Example 10/Comparative Example 1): 1.63
The silicon nitride film of Example 10 had a Si—N peak intensity ratio of 1.63, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 11)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (NHCH(C ₂ H ₅ ) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.37 (Å/cycle)
Refractive index: 1.98
Si—N peak intensity ratio at a film thickness of 30 nm (Example 11/Comparative Example 1): 1.77
The silicon nitride film of Example 11 had a Si—N peak intensity ratio of 1.77, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 12)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (NHCH(C ₂ H ₅ ) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.20 (Å/cycle)
Refractive index: 1.86
Si—N peak intensity ratio at a film thickness of 30 nm (Example 12/Comparative Example 1): 1.55
The silicon nitride film of Example 12 had a Si—N peak intensity ratio of 1.55, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 13)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (N(C(CH ₃ ) ₃ ) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.21 (Å/cycle)
Refractive index: 1.88
Si—N peak intensity ratio at a film thickness of 30 nm (Example 13/Comparative Example 1): 1.59
The silicon nitride film of Example 13 had a Si—N peak intensity ratio of 1.59, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 14)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (N(C(CH ₃ ) ₃ ) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.09 (Å/cycle)
Refractive index: 1.83
Si—N peak intensity ratio at a film thickness of 30 nm (Example 14/Comparative Example 1): 1.50
The silicon nitride film of Example 14 had a Si—N peak intensity ratio of 1.50, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 15)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (N(CH(CH ₃ ) ₂ ) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.22 (Å/cycle)
Refractive index: 1.90
Si—N peak intensity ratio at a film thickness of 30 nm (Example 15/Comparative Example 1): 1.63
The silicon nitride film of Example 15 had a Si—N peak intensity ratio of 1.63, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 16)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (N(CH(CH ₃ ) ₂ ) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.10 (Å/cycle)
Refractive index: 1.85
Si—N peak intensity ratio at a film thickness of 30 nm (Example 16/Comparative Example 1): 1.54
The silicon nitride film of Example 16 had a Si—N peak intensity ratio of 1.54, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 17)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (N((CH ₂ ) ₂ (CH ₃ )) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.20 (Å/cycle)
Refractive index: 1.91
Si—N peak intensity ratio at a film thickness of 30 nm (Example 17/Comparative Example 1): 1.64
The silicon nitride film of Example 17 had a Si—N peak intensity ratio of 1.64, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 18)
[Film formation conditions]
Film formation was performed under the same film formation conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (N((CH ₂ ) ₂ (CH ₃ )) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.07 (Å/cycle)
Refractive index: 1.84
Si—N peak intensity ratio at a film thickness of 30 nm (Example 18/Comparative Example 1): 1.52
The silicon nitride film of Example 18 had a Si—N peak intensity ratio of 1.52, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 19)
[Film formation conditions]
_{A film was formed under the same film forming conditions as in Comparative Example 1, except that Si2H2Cl2 (} N(C( _CH3 ) _{2 (C2H5))2)2 was used as} the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.18 (Å/cycle)
Refractive index: 1.82
Si—N peak intensity ratio at a film thickness of 30 nm (Example 19/Comparative Example 1): 1.48
The silicon nitride film of Example 19 had a Si—N peak intensity ratio of 1.48, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 20)
[Film formation conditions]
A film _was formed under the _same film forming conditions as in Comparative Example 1, except that _Si2Cl2 (N( _C ( _CH3 ) ₂ ( _C2H5 )) ₂ ) ₄ ( _C2H5 )) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.05 (Å/cycle)
Refractive index: 1.80
Si—N peak intensity ratio at a film thickness of 30 nm (Example 20/Comparative Example 1): 1.44
The silicon nitride film of Example 20 had a Si—N peak intensity ratio of 1.44, and it was confirmed that the denseness of the silicon nitride film was improved as compared with that of Example 1.

(Example 20)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (N(CH(CH ₃ )(C ₂ H ₅ )) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.19 (Å/cycle)
Refractive index: 1.87
Si—N peak intensity ratio at a film thickness of 30 nm (Example 21/Comparative Example 1): 1.57
The silicon nitride film of Example 21 had a Si—N peak intensity ratio of 1.57, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 22)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (N(CH(CH ₃ )(C ₂ H ₅ )) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.10 (Å/cycle)
Refractive index: 1.82
Si—N peak intensity ratio at a film thickness of 30 nm (Example 22/Comparative Example 1): 1.48
The silicon nitride film of Example 22 had a Si—N peak intensity ratio of 1.48, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 23)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ H ₂ Cl ₂ (N(CH(C ₂ H ₅ ) ₂ ) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.16 (Å/cycle)
Refractive index: 1.83
Si—N peak intensity ratio at a film thickness of 30 nm (Example 23/Comparative Example 1): 1.50
The silicon nitride film of Example 23 had a Si—N peak intensity ratio of 1.50, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 24)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₂ (N(CH(C ₂ H ₅ ) ₂ ) ₂ ) ₄ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.06 (Å/cycle)
Refractive index: 1.82
Si—N peak intensity ratio at a film thickness of 30 nm (Example 24/Comparative Example 1): 1.48
The silicon nitride film of Example 24 had a Si—N peak intensity ratio of 1.48, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 25)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NHC(CH ₃ ) ₃ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.33 (Å/cycle)
Refractive index: 1.82
Si—N peak intensity ratio at a film thickness of 30 nm (Example 25/Comparative Example 1): 1.48
The silicon nitride film of Example 25 had a Si—N peak intensity ratio of 1.48, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 26)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NHCH(CH ₃ ) ₂ ) 2 was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.35 (Å/cycle)
Refractive index: 1.84
Si—N peak intensity ratio at a film thickness of 30 nm (Example 26/Comparative Example 1): 1.52
The silicon nitride film of Example 26 had a Si—N peak intensity ratio of 1.52, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 27)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NH(CH ₂ ) ₂ (CH ₃ )) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.32 (Å/cycle)
Refractive index: 1.83
Si—N peak intensity ratio at a film thickness of 30 nm (Example 27/Comparative Example 1): 1.50
The silicon nitride film of Example 27 had a Si—N peak intensity ratio of 1.50, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 28)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NC(CH ₃ ) ₂ (C ₂ H ₅ )) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.30 (Å/cycle)
Refractive index: 1.80
Si—N peak intensity ratio at a film thickness of 30 nm (Example 28/Comparative Example 1): 1.44
The silicon nitride film of Example 28 had a Si—N peak intensity ratio of 1.44, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 29)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NHCH(CH ₃ )(C ₂ H ₅ )) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.34 (Å/cycle)
Refractive index: 1.82
Si—N peak intensity ratio at a film thickness of 30 nm (Example 29/Comparative Example 1): 1.48
The silicon nitride film of Example 29 had a Si—N peak intensity ratio of 1.48, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 30)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (NHCH(C ₂ H ₅ ) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.33 (Å/cycle)
Refractive index: 1.81
Si—N peak intensity ratio at a film thickness of 30 nm (Example 30/Comparative Example 1): 1.46
The silicon nitride film of Example 30 had a Si—N peak intensity ratio of 1.46, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 31)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (N(C(CH ₃ ) ₃ ) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.19 (Å/cycle)
Refractive index: 1.77
Si—N peak intensity ratio at a film thickness of 30 nm (Example 31/Comparative Example 1): 1.39
The silicon nitride film of Example 31 had a Si—N peak intensity ratio of 1.39, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 32)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (N(CH(CH ₃ ) ₂ ) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.20 (Å/cycle)
Refractive index: 1.79
Si—N peak intensity ratio at a film thickness of 30 nm (Example 32/Comparative Example 1): 1.43
The silicon nitride film of Example 32 had a Si—N peak intensity ratio of 1.43, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 33)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (N((CH ₂ ) ₂ (CH ₃ )) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.18 (Å/cycle)
Refractive index: 1.79
Si—N peak intensity ratio at a film thickness of 30 nm (Example 33/Comparative Example 1): 1.43
The silicon nitride film of Example 33 had a Si—N peak intensity ratio of 1.43, and it was confirmed that the denseness of the silicon nitride film was improved as compared with that of Example 1.

(Example 34)
[Film formation conditions]
A film was formed under the same film forming conditions as in Example 1, except that Si ₂ Cl ₄ (N(C(CH ₃ ) ₂ (C ₂ H ₅ )) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.16 (Å/cycle)
Refractive index: 1.75
Si—N peak intensity ratio at a film thickness of 30 nm (Example 34/Comparative Example 1): 1.35
The silicon nitride film of Example 34 had a Si—N peak intensity ratio of 1.35, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 35)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (N(CH(CH ₃ )(C ₂ H ₅ )) ₂ ) ₂ was used instead of HCDS as the silicon-containing compound.
[Evaluation Results]
・GPC: 0.17 (Å/cycle)
Refractive index: 1.78
Si—N peak intensity ratio at a film thickness of 30 nm (Example 35/Comparative Example 1): 1.41
The silicon nitride film of Example 35 had a Si—N peak intensity ratio of 1.41, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 36)
[Film formation conditions]
A film was formed under the same film forming conditions as in Comparative Example 1, except that Si ₂ Cl ₄ (N(CH(C ₂ H ₅ ) ₂ ) ₂ ) ₂ was used as the silicon-containing compound instead of HCDS.
[Evaluation Results]
・GPC: 0.14 (Å/cycle)
Refractive index: 1.76
Si—N peak intensity ratio at a film thickness of 30 nm (Example 36/Comparative Example 1): 1.37
The silicon nitride film of Example 36 had a Si—N peak intensity ratio of 1.37, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Evaluation result 1)
Infrared absorption spectroscopy was performed on the silicon nitride films of Examples 1 to 36, and it was confirmed that no Si—O vibration was detected and that clean Si—N vibration was observed. Therefore, it was confirmed that all of the silicon nitride films of Examples 1 to 36 were good quality SiN films.

(Evaluation result 2)
Among Examples 1 to 26, compounds containing the same substituents were compared with each other to evaluate the relationship between the number of various substituents and the film quality.
In Examples 1 to 26, good quality silicon nitride films were formed, but as the number of substituents increased, the GPC, refractive index, and Si-N intensity ratio decreased. This is believed to be due to the large molecular structures of the various substituents, which caused steric hindrance in the above-mentioned chemical adsorption reaction (first reaction) and nitridation reaction (second reaction).

From these results, it was confirmed that in order to form a high-quality silicon nitride film at a film formation temperature of less than 500°C, it is preferable to use a chloroaminodisilane compound (examples 3, 5, 7, 9, 11, 13, 27 to 32) as a silicon-containing compound, which is less affected by steric hindrance due to substituents.

(Evaluation result 3)
The results of Examples 1 to 38 were compared to evaluate the influence of the type of substituent group possessed by the chloroaminodisilane compound contained in the composition for forming a silicon-containing thin film of the present invention.
As a result, it was confirmed that a good quality silicon nitride film was formed in the following order: "-NH(tBu ₎ " group ≧ "-NHCH(CH ₃ ) ₂ " group ≧ "-NH(CH ₂ ) ₂ CH ₃ " group ≧ "-N(CH(CH 3 ) ₂ ) ₂ " group ≧ "-N((C ₂ H ₄ )CH ₃ ) ₂ " group. This is thought to be due to the effect of steric hindrance caused by the molecular structure of each substituent.

These results confirm that the chloroaminodisilane compound represented by formula 11 (compound 11) is less affected by steric hindrance due to its molecular structure than the chloroaminodisilane compound represented by formula 12 (compound 12), and therefore forms a high-quality silicon nitride film.

(Evaluation result 4)
The results of Examples 1 to 24 were compared with the results of Examples 25 to 36 to evaluate the effect of the number of chlorines contained in the chloroaminodisilane compound contained in the composition for forming a silicon-containing thin film of the present invention.
As a result, it was confirmed that a better quality silicon nitride film was formed with a compound with two chlorines than with a compound with four chlorines. This is thought to be due to the effects of the chlorine remaining in the film and the hydrogen chloride produced as a by-product.

These results confirm that, compared to the chloroaminodisilane compounds represented by formulas 13 and 14, the chloroaminodisilane compounds represented by formulas 11 and 12 are less susceptible to residual chlorine in the film and to the by-product hydrogen chloride, resulting in the formation of high-quality silicon nitride films.

(Evaluation result 5)
The difference between the chloroaminosilane compound and the chloroaminodisilane compound was evaluated by comparing the results of Comparative Example 3 and Example 17. Both compounds have one diisopropylamino group per Si atom, but the chloroaminodisilane compound formed a better quality film at a faster film formation rate.
In the silicon nitride film of Comparative Example 3, many unreacted Si-H bonds remain, whereas the silicon nitride film of Example 17 has Si-Si bonds. In either case where these bonds are broken to become Si-N-Si bonds or remain unbroken, the proportion of Si or N in the film is greater than the Si-H bonds remaining in the film, and this is believed to be the reason why a dense and good quality film can be obtained.
In addition, it is believed that the film formation rate was faster for the chloroaminodisilane compound, based on the number of Si--N bonds generated per mol of the compound and the size of the molecule.

(Evaluation result 6)
Using HCDS as the silicon-containing compound and _NH3 as the nitrogen-containing compound, several tens of film formation experiments were carried out by the ALD method at film formation temperatures of 450 to 700°C.
After the film formation experiment, when the exhaust pipe downstream of the pressure reducing device (pressure reducing pump) 4 in the exhaust path L2 of the film formation apparatus 1 was opened, it was confirmed that the pipe was clogged with ammonium chloride.

In response to this, after several dozen ALD film formation experiments were performed under the film formation conditions of Examples 3 to 38, the exhaust piping downstream of the pressure reduction device (pressure reduction pump) 4 was opened, and it was confirmed that no ammonium chloride had accumulated.

(Example 37)
[Film formation conditions]
A film was formed under the same film forming conditions as in Example 1 above, except that hydrazine (NH ₂ NH ₂ ) was used instead of ammonia (NH ₃ ) as the nitrogen-containing compound.
[Evaluation Results]
・GPC: 0.64 (Å/cycle)
Refractive index: 2.07
Si—N peak intensity ratio at a film thickness of 30 nm (Example 37/Comparative Example 1): 2.02
The silicon nitride film of Example 37 had a Si—N peak intensity ratio of 2.02, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 38)
[Film formation conditions]
A film was formed under the same film forming conditions as in Example 1, except that monomethylhydrazine (NH ₂ NH(CH ₃ )) was used as the nitrogen-containing compound instead of ammonia (NH ₃ ).
[Evaluation Results]
・GPC: 0.53 (Å/cycle)
Refractive index: 2.10
Si—N peak intensity ratio at a film thickness of 30 nm (Example 38/Comparative Example 1): 1.95
The silicon nitride film of Example 38 had a Si—N peak intensity ratio of 1.95, and it was confirmed that the denseness of the silicon nitride film was improved as compared with Comparative Example 1.

(Example 39)
[Film formation conditions]
A film was formed under the same film forming conditions as in Example 1, except that a mixed raw material of hydrazine (NH ₂ NH ₂ ) and ammonia (NH ₃ ) was used as the nitrogen-containing compound.
[Evaluation Results]
・GPC: 0.61 (Å/cycle)
Refractive index: 1.99
Si—N peak intensity ratio at a film thickness of 30 nm (Example 39/Comparative Example 1): 2.01
The silicon nitride film of Example 39 had a Si—N peak intensity ratio of 2.01, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 40)
[Film formation conditions]
A film was formed under the same film forming conditions as in Example 1, except that a mixed raw material of monomethylhydrazine (NH ₂ NH(CH ₃ )) and ammonia (NH ₃ ) was used as the nitrogen-containing compound.
[Evaluation Results]
・GPC: 0.49 (Å/cycle)
Refractive index: 2.04
Si-N peak intensity ratio at a film thickness of 30 nm (Example 40/Comparative Example 1): 1.90
The silicon nitride film of Example 40 had a Si—N peak intensity ratio of 1.90, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Example 41)
[Film formation conditions]
The film was formed under the same film forming conditions as in Example 1, except that the film forming temperature was changed to 400°C.
[Evaluation Results]
・GPC: 0.27 (Å/cycle)
Refractive index: 1.96
Si—N peak intensity ratio at a film thickness of 30 nm (Example 43/Comparative Example 1): 1.58
The silicon nitride film of Example 41 had a Si—N peak intensity ratio of 1.58, and it was confirmed that the density of the silicon nitride film was improved, even though the temperature was 50° C. lower than that of Comparative Example 1.

(Example 42)
[Film formation conditions]
The film was formed under the same film forming conditions as in Example 1, except that the film forming temperature was changed to 350°C.
[Evaluation Results]
・GPC: 0.17 (Å/cycle)
Refractive index: 1.86
Si—N peak intensity ratio at a film thickness of 30 nm (Example 44/Comparative Example 1): 1.51
The silicon nitride film of Example 42 had a Si—N peak intensity ratio of 1.51, and it was confirmed that the density of the silicon nitride film was improved, even though the temperature was 100° C. lower than that of Comparative Example 1.

(Example 43)
[Film formation conditions]
Film formation temperature (substrate surface temperature): 450°C
Silicon-containing compound: _SiH2Cl (NHtBu)
・Nitrogen-containing compounds: NH ₃ , NH ₂ NH ₂
Number of cycles repeated: 300 times

[cycle]
Step 1: A silicon-containing compound is supplied into the process chamber for 10 seconds.
Step 2: Purge with _N2 for 10 seconds to remove unreacted silicon-containing compounds.
Step 3: NH ₃ (first reactive gas) is supplied into the processing chamber for 10 seconds.
Step 4: Purge with _N2 for 10 seconds to remove unreacted _NH3 .
Step 5: NH ₂ NH ₂ (second reaction gas) is supplied into the processing chamber for 10 seconds.
Step 6: Purge with _N2 for 10 seconds to remove unreacted _{NH2NH2 .}

[Evaluation Results]
・GPC: 0.52 (Å/cycle)
Refractive index: 2.06
Si—N peak intensity ratio at a film thickness of 30 nm (Example 43/Comparative Example 1): 2.03
The silicon nitride film of Example 43 had a Si—N peak intensity ratio of 2.03, and it was confirmed that the denseness of the silicon nitride film was significantly improved as compared with Comparative Example 1.

(Evaluation result 7)
As shown in Table 2, in Examples 37 to 40, the nitrogen-containing compounds used as the nitrogen-containing raw materials were different from those in Example 1. The results of Example 1 were compared with the results of Examples 37 to 40 to evaluate the film formation amount and film quality when nitrogen-containing raw materials containing different nitrogen-containing compounds were used.

As shown in Example 37, when hydrazine (NH ₂ NH ₂ ) was used as the nitrogen-containing compound, the GPC was significantly improved and the density was also improved compared to when ammonia (NH ₃ ) was used. This is believed to be due to the high reactivity of hydrazine compounds.

In addition, as shown in Example 38, when monomethylhydrazine (NH ₂ NH(CH ₃ )) is used as a nitrogen-containing compound, GPC and refractive index are improved, and denseness is slightly decreased, compared with the case of using ammonia (NH ₃ ). This is considered to be due to the methyl group in monomethylhydrazine slightly inhibiting the formation of a dense film structure. However, since monomethylhydrazine contains a methyl group, it has the advantage of being able to appropriately control the amount of carbon in the film.

In addition, as shown in Examples 39 and 40, it was confirmed that when a mixture of two or more nitrogen-containing compounds was used as the nitrogen-containing compound, the same effects as those of Examples 37 and 38 could be obtained. In particular, a mixture of ammonia (NH ₃ ) and a hydrazine compound is effective in reducing the concentration of the highly dangerous hydrazine compound.

As explained above, it has been confirmed that using a hydrazine compound as a nitrogen-containing compound when forming a silicon nitride film is effective because it improves one or more of the following: density, film formation amount, and refractive index, compared to when ammonia is used.

It was also confirmed that when a chloroaminodisilane compound represented by formula 1 other than Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₂ was used as the silicon-containing compound, the same tendency as in Example 1 and Examples 37 to 40 was observed.

It was also confirmed that when other hydrazine compounds and amine compounds were used as the nitrogen-containing compound, the amount of film formed was improved compared to when ammonia was used alone as the nitrogen-containing compound.

(Evaluation result 8)
Examples 41 and 42 are different from Example 1 in the silicon-containing compound used as the silicon-containing raw material.
Moreover, Examples 41 and 42 differ from Comparative Example 1 and Example 1 in the film formation temperature.
By comparing Comparative Example 1, Example 1, Example 41, and Example 42, the temperature dependency of film formation using a chloroaminodisilane compound and ammonia (NH ₃ ) was evaluated.

As shown in Table 2, when comparing Examples 3, 41, and 42, there was a tendency for the GPC, refractive index, and density to decrease as the film formation temperature decreased. However, when compared with Comparative Example 1, it was confirmed that good film formation amount, film quality, and density were obtained in all of Examples 3, 41, and 42. From these results, it was confirmed that the chloroaminodisilane compound shown in Formula 1 is a promising material as a silicon-containing compound to be included in a composition for forming a silicon-containing thin film, even in the low temperature range of 350°C.

In addition, when the film was formed at a film formation temperature lower than 350°C, it was confirmed that a high-quality silicon nitride film was formed as a result of comparison with Comparative Example 1.

It was also confirmed that the same tendency was obtained when a chloroaminodisilane compound represented by formula 1 other than Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₂ was used.

Furthermore, it was confirmed that the same tendency was obtained when using nitrogen-containing compounds other than ammonia as the nitrogen-containing compound. In particular, it was confirmed that when a hydrazine compound was used as the nitrogen-containing raw material, GPC and denseness were improved compared to when ammonia was used.

(Evaluation result 9)
Example 1 is an example (two-step reaction) in which ammonia (NH ₃ ) was used alone as the nitrogen-containing compound contained in the nitrogen-containing compound.
Example 37 is an example (two-step reaction) in which hydrazine (NH ₂ NH ₂ ) was used alone as the nitrogen-containing compound contained in the nitrogen-containing compound.
Example 43 is an example (three-step reaction) in which a first reaction gas consisting of a nitrogen-containing compound containing ammonia (NH ₃ ) and a second reaction gas consisting of a nitrogen-containing compound containing hydrazine are alternately supplied as reaction gases.
The results of Examples 1, 37 and 43 were compared to evaluate the three-step reaction (feeding of a second reactant gas).

As shown in Table 2, it was confirmed that the three-step reaction shown in Example 43 formed a silicon nitride film of equal or better quality than the two-step reactions shown in Examples 3 and 37. In particular, the density of the silicon nitride film was improved compared to the two-step reaction, confirming the effect of supplying the second reaction gas.

It was confirmed that the same tendency was obtained when a chloroaminodisilane compound represented by formula 1 other than Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₂ was used as the silicon-containing compound.
It was also confirmed that similar trends were obtained when other nitrogen-containing compounds were used as the second reactive gas. Among them, it was confirmed that the GPC and denseness were particularly good when a hydrazine compound was used.

(Example 44)
[Film formation conditions]
The film was formed under the same film forming conditions as in Comparative Example 1, except that the film forming temperature was changed to 550°C.
[Evaluation Results]
・GPC: 0.15 (Å/cycle)
Refractive index: 1.90
Si—N peak intensity ratio at a film thickness of 30 nm (Example 44/Comparative Example 1): 1.64
The silicon nitride film of Example 44 had a Si—N peak intensity ratio of 1.64, and it was confirmed that the denseness of the silicon nitride film was improved by increasing the film formation temperature by 100° C. compared to Comparative Example 1 (film formation temperature 450° C.).

(Example 45)
[Film formation conditions]
The film was formed under the same film forming conditions as in Example 1, except that the film forming temperature was changed to 550°C.
[Evaluation Results]
・GPC: 0.80 (Å/cycle)
Refractive index: 2.05
Si—N peak intensity ratio at a film thickness of 30 nm (Example 45/Comparative Example 1): 2.10
The silicon nitride film of Example 45 had a Si—N peak intensity ratio of 2.10, and it was confirmed that the density of the silicon nitride film was improved by increasing the film formation temperature by 100° C. compared to Example 1 (film formation temperature 450° C.).

(Evaluation result 10)
The results of Comparative Example 1, Example 1, Example 44, and Example 45 were compared to evaluate the amount of film formed and the film quality at a film formation temperature of 500° C. or higher. It was confirmed that the GPC, refractive index, and denseness were improved at a film formation temperature of 550° C. compared to 450° C.

Comparing Comparative Example 1 and Example 44, it was confirmed that when the silicon-containing compound contained in the source gas was HCDS, the film quality was significantly improved by setting the film formation temperature to 550°C.

In addition, as shown in Table 3, when Example 44 and Example 45 are compared, it was confirmed that a better quality _{silicon nitride} film was formed when the silicon-containing compound contained in the source gas was _Si2H2Cl2 (NHC( _CH3 ) ₃ ) ₂ .

It was confirmed that the same tendency was obtained when a chloroaminodisilane compound represented by formula 1 other than Si ₂ H ₂ Cl ₂ (NHC(CH ₃ ) ₃ ) ₂ was used as the silicon-containing raw material.

As explained above, it has been confirmed that the chloroaminodisilane compound shown in formula 1 is a promising material as a silicon-containing compound to be included in a composition for forming a silicon-containing thin film, even in the high-temperature range of film formation temperatures of 500°C or higher.

(Example 46)
[Film formation conditions]
Film formation temperature (substrate surface temperature): 450°C
Silicon _- containing compound: _Si2H2Cl2 ( _NHtBu ) ₂
・Nitrogen-containing compound: _NH3
Processing time: 30 minutes

[Film formation method]
A silicon-containing compound and a nitrogen-containing compound were supplied as described below, and a film was formed by a CVD method.
Step 1: SiH ₂ Cl(NHtBu) ₂ is supplied into a processing chamber.
Step 2: _NH3 is supplied into the processing chamber.

[Evaluation Results]
・Deposition amount: 20 (Å/min)
Refractive index: 2.02
Si—N peak intensity ratio at a film thickness of 30 nm (Example 49/Comparative Example 1): 1.88
The silicon nitride film of Example 49 had a Si—N peak intensity ratio of 1.88, and it was confirmed that a good quality silicon nitride film could be obtained even when formed by the CVD method.

In addition, it was confirmed that a high-quality silicon nitride film was formed when a chloroaminodisilane compound represented by formula 1 other than Si ₂ H ₂ Cl ₂ (NHtBu) ₂ was used as the silicon-containing compound contained in the composition for forming a silicon-containing thin film.

1: Film forming apparatus 2: Processing chamber 3: Temperature control device 4: Pressure reducing device 5: Source material container 6: Vaporizer 7: Heater P: Substrate to be processed
L1: Purge gas supply path L2: Exhaust path L3: Raw material gas supply path L4: Reactant gas supply path

Claims (11)

A composition for forming a silicon-containing thin film, which is used as a silicon-containing raw material when forming a silicon-containing thin film by chemical vapor deposition, comprising:
A composition for forming a silicon-containing thin film, comprising at least one selected from the group consisting of chloroaminodisilane compounds represented by the following formulas 11 and 13 :

In formulas 11 and 13 , R1, R2, and R3 are each independently selected linear or branched saturated alkyl groups having 1 to 5 carbon atoms.
In addition, in formula 11 , x and y are integers selected from 0 to 2 and satisfy 1≦x+y. A method for forming a silicon-containing thin film by chemical vapor deposition, comprising the steps of:
A method for forming a silicon-containing thin film, comprising using the composition for forming a silicon-containing thin film according to claim 1 as a silicon-containing raw material. controlling a surface temperature of a substrate to be processed in a processing chamber to a required temperature, and supplying the silicon-containing source material to the substrate to be processed in the processing chamber;
The method for forming a silicon-containing thin film according to claim 2 , further comprising: supplying a nitrogen-containing source to the substrate in the processing chamber. controlling a surface temperature of a substrate to be processed in a processing chamber to a required temperature, and supplying the silicon-containing source material to the substrate to be processed in the processing chamber;
stopping the supply of the silicon-containing source material;
supplying a nitrogen-containing source to the substrate in the treatment chamber;
and stopping the supply of the nitrogen-containing source material. The method for forming a silicon-containing thin film according to claim 4, wherein the cycle further includes a step of removing the silicon-containing source material remaining in the processing chamber from the processing chamber. The method for forming a silicon-containing thin film according to claim 4 or 5, wherein the cycle further includes a step of removing the nitrogen-containing source remaining in the processing chamber from the processing chamber. The method for forming a silicon-containing thin film according to any one of claims 4 to 6, wherein the cycle further includes a step of supplying a silicon-containing raw material different from the silicon-containing raw material to the substrate to be processed in the processing chamber. The method for forming a silicon-containing thin film according to any one of claims 4 to 7, wherein the cycle further includes a step of supplying a nitrogen-containing source different from the nitrogen-containing source to the substrate to be treated in the treatment chamber. The method for forming a silicon-containing thin film according to any one of claims 3 to 8, wherein the nitrogen-containing source contains one or more nitrogen-containing compounds selected from the group consisting of ammonia, hydrazine, monomethylhydrazine, dimethylhydrazine, tertiary butylhydrazine, dimethylamine, monomethylamine, and tertiary butylamine. The method for forming a silicon-containing thin film according to any one of claims 2 to 9, wherein the silicon-containing thin film is a silicon nitride film or a silicon carbonitride film. The method for forming a silicon-containing thin film according to any one of claims 2 to 10, wherein the surface temperature of the substrate to be treated in the treatment chamber is controlled to a temperature less than 500°C.

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