JP5304983B2 - Silicon-containing film forming composition - Google Patents

Description

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

  In recent years, large-scale semiconductor integrated circuits (ULSI) have been strongly demanded for higher-speed processing in order to cope with an increasing amount of information processing and complexity of functions. The speeding up of ULSI has been realized by miniaturization and high integration of elements in a chip and multilayering of films. However, with the miniaturization of elements, wiring resistance and inter-wiring parasitic capacitance increase, and wiring delay is becoming a dominant factor in signal delay of the entire device. In order to avoid this problem, introduction of a low resistivity wiring material or a low dielectric constant (Low-k) interlayer insulating film material is an essential technique.

As a wiring material, the use of Cu, which is a metal having a low resistivity instead of Al, has been studied and put into practical use. On the other hand, as an interlayer insulating film material, a silica (SiO ₂ ) film formed by a vacuum process such as a chemical vapor deposition (CVD) method is frequently used, but the low dielectric constant (Low-k) of the interlayer insulating film is used. Various proposals have been made for conversion.

Examples of the low dielectric constant interlayer insulating film include inorganic interlayer insulating films such as a porous silica film having a reduced silica (SiO ₂ ) film density, FSG which is a silica film doped with F, and a SiOC film doped with C. Examples thereof include an organic interlayer insulating film such as a film, polyimide, polyarylene, and polyarylene ether.

  In addition, for the purpose of forming a more uniform interlayer insulating film, a coating type interlayer insulating film mainly composed of a hydrolytic condensation product of tetraalkoxysilane called an SOG film or an organic alkoxysilane is hydrolyzed and condensed. An organic SOG film made of polysiloxane has been proposed.

  Here, a topic is changed about the formation method of an interlayer insulation film. The formation method of the interlayer insulating film can be roughly classified into two methods. One is a coating method (or spin coating method) in which a polymer solution for forming an insulating film is applied using a spin coater or the like, and the other is a coating method (or spin coating method). This is a chemical vapor deposition (CVD) method in which a film is deposited by utilizing the reaction in (1).

  In both coating methods and chemical vapor deposition methods, proposals have been made for inorganic materials and organic materials. In general, the coating method has good film uniformity, but often has poor adhesion to a substrate or a barrier metal. On the other hand, in chemical vapor deposition, it has been pointed out that film uniformity is often a problem and low dielectric constant of the film is often insufficient. Since the film is formed by the CVD method, it is advantageous in terms of operation and has good advantages such as good adhesion to the substrate, and has an advantage as a film forming method.

  Therefore, many proposals have been made by chemical vapor deposition. In particular, many silane compounds used for the reaction have been proposed. For example, those using dialkoxysilane (Japanese Patent Laid-Open Nos. 11-288931 and 2002-329718), and those using cyclic silane compounds (Japanese Patent Laid-Open No. 2002-503879, Japanese Patent Laid-Open No. 2005-513766) ), And those using a silane compound in which tertiary carbon or secondary carbon and Si are bonded (Japanese Patent Application Laid-Open Nos. 2004-6607 and 2005-51192) have been proposed. By using such a material, a film having a low dielectric constant and sufficient adhesion with a barrier metal or the like is obtained.

However, since these silane compounds are chemically stable, they require extreme conditions during film formation by chemical vapor deposition, and conversely, they are chemically unstable and are supplied into the chamber. There are those that cause a reaction in the piping and those that have poor storage stability of the silane compound itself. In addition, depending on the selected compound, the insulating film after film formation has a high hygroscopic property, which causes a problem of increasing the leakage current. Further, in the actual manufacturing process of a semiconductor device, a process of processing an interlayer insulating film using RIE (Reactive Ion Etching) is often used, and the problem that the dielectric constant of the film increases during the RIE, There is a problem that the interlayer insulating film is damaged by the fluoric acid chemical used in the subsequent cleaning process, and an interlayer insulating film having high processing resistance is required.
JP-A-11-288931 JP 2002-329718 A Japanese translation of PCT publication No. 2002-503879 JP 2005-513766 gazette Japanese Patent Laid-Open No. 2004-6607 JP 2005-51192 A

  INDUSTRIAL APPLICABILITY The present invention can be suitably used in semiconductor elements and the like that are desired to be highly integrated and multi-layered, and forms a film having excellent mechanical strength, low dielectric constant, low hygroscopicity, and high processing resistance. A silicon-containing film-forming composition that can be formed, a silicon-containing film forming method using the composition, and a silicon-containing film obtained by the forming method are provided.

  The present inventors have used a silicon-containing film-forming composition comprising a silicon-carbon-silicon skeleton and an organosilane compound having a specific structure in which oxygen is bonded to any one of silicon and a pore-forming agent. The present inventors have found that a silicon-containing film having a low relative dielectric constant, low hygroscopicity, and high processing resistance can be formed.

  The silicon-containing film forming composition according to one embodiment of the present invention includes an organosilane compound represented by the following general formula (1) and a pore forming agent.

・・・・・（１）
（式中、Ｒ^１〜Ｒ^４は、同一または異なり、水素原子、炭素数１〜４のアルキル基、ビニル基、またはフェニル基を示し、Ｒ^５は炭素数１〜４のアルキル基、アセチル基、またはフェニル基を示し、ｎは１〜３の整数を示し、ｍは１〜２の整数を示す。）

(1)
(Wherein R ^{1 to} R ⁴ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, and R ⁵ represents an alkyl group having 1 to 4 carbon atoms or an acetyl group. Or n represents an integer of 1 to 3, and m represents an integer of 1 to 2.)

  The silicon-containing film-forming composition may include 0.05 to 10,000 parts by weight of the pore forming agent with respect to 100 parts by weight of the organosilane compound.

  The silicon-containing film forming composition can be used for film formation by chemical vapor deposition.

The method for forming a silicon-containing film according to one aspect of the present invention includes a step of forming a deposited film by chemical vapor deposition using the composition for forming a silicon-containing film, a step of curing the deposited film,
including.

  In the method for forming a silicon-containing film, the step of curing the deposited film can be performed by at least one selected from heating, electron beam irradiation, ultraviolet irradiation, and oxygen plasma.

The silicon-containing film according to one embodiment of the present invention is obtained by the method for forming a silicon-containing film. In this case, the silicon-containing film can include a —Si— (CH ₂ ) _n —Si—O— moiety (where n represents an integer of 1 to 3).

  The silicon-containing film may have a dielectric constant of 2.7 or less.

  According to the silicon-containing film-forming composition, a semiconductor element or the like that is desired to be highly integrated and multi-layered by including the organosilane compound represented by the general formula (1) and a pore-forming agent. Insulating films that are chemically stable and excellent in mechanical strength, have a low relative dielectric constant, low moisture absorption, and high processing resistance such as chemical resistance can be formed. In particular, since the silicon-containing film-forming composition contains a pore-forming agent, the insulating film can be made porous, so that the insulating film has excellent mechanical strength and low relative dielectric constant (for example, relative dielectric constant). 2.7 or less insulating film) can be obtained. The silicon-containing film forming composition is useful in that it can form a homogeneous film having a low relative dielectric constant and excellent mechanical strength in film formation by chemical vapor deposition.

In the organosilane compound represented by the general formula (1), all the substituents of one silicon atom and one or two substituents of the other silicon atom are hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, It is substituted with either a vinyl group or a phenyl group, and the oxygen atom is bonded only to two or one substituent of one silicon atom. Although the detailed mechanism is not clear, in the film formation using the silicon-containing film forming composition, among the organosilane compounds represented by the general formula (1), R ¹ R ² R ³ —Si— (CH ₂ ) The _n -Si-R ⁴ part acts as a function to weaken the damage received from RIE and increase the resistance to fluoric acid chemicals, and the -Si- (OR ⁵ ) _m part is -Si-O-Si. -It is presumed that an insulating film having excellent mechanical strength, low relative dielectric constant and high processing resistance can be obtained because a bond is formed and a skeleton having a high degree of three-dimensional crosslinking is formed.

  The silicon-containing film is excellent in mechanical strength, has a low relative dielectric constant, and high processing resistance.

  The present invention will be specifically described below.

1. 1. Silicon-containing film forming composition 1.1. Configuration of Silicon-Containing Film-Forming Composition A silicon-containing film-forming composition according to an embodiment of the present invention includes an organosilane compound represented by the following general formula (1) and a pore-forming agent.

・・・・・（１）
（式中、Ｒ^１〜Ｒ^４は、同一または異なり、水素原子、炭素数１〜４のアルキル基、ビニル基、またはフェニル基を示し、Ｒ^５は炭素数１〜４のアルキル基、アセチル基、またはフェニル基を示し、ｎは１〜３の整数を示し、ｍは１〜２の整数を示す。）

(1)
(Wherein R ^{1 to} R ⁴ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, and R ⁵ represents an alkyl group having 1 to 4 carbon atoms or an acetyl group. Or n represents an integer of 1 to 3, and m represents an integer of 1 to 2.)

In the general formula (1), R ^{1 to} R ⁴ are the same or different and represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group. Here, examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. As R ^{1 to} R ⁴ , a methyl group, a vinyl group, and a hydrogen atom are particularly preferable.

In the general formula (1), ^{R 5} represents an alkyl group having 1 to 4 carbon atoms, an acetyl group, a phenyl group. The alkyl group having 1 to 4 carbon atoms, for example, include the same alkyl groups as those exemplified as the R ¹ to R ^4. R ⁵ is particularly preferably a methyl group or an ethyl group.

  Furthermore, in the said General formula (1), n shows the integer of 1-3 and m shows the integer of 1-2.

  In the above general formula (1), examples of the organosilane compound with n = 1 and m = 1 include the following.

  In the above general formula (1), examples of the organosilane compound in which n = 1 and m = 2 include those shown below.

  In the above general formula (1), examples of the organosilane compound in which n = 2 and m = 1 include the following.

  In the general formula (1), examples of the compound where n = 2 and m = 2 include the following.

  In the general formula (1), examples of the compound where n = 3 and m = 1 include the following.

  In the general formula (1), examples of the compound where n = 3 and m = 2 include the following.

In the organosilane compound represented by the general formula (1), the total number of hydrogen atoms in R ^{1 to} R ⁴ is preferably 0 to 2 from the viewpoints of ease of synthesis and purification and ease of handling. More preferably, it is 0-1.

  In the organosilane compound represented by the general formula (1), m = 1 and 2 are preferable and m = 1 is more preferable from the viewpoint of mechanical strength of the silicon-containing film.

  The silicon-containing film-forming composition according to this embodiment preferably contains 5 to 100 mol%, more preferably 10 to 100 mol% of the organosilane compound represented by the general formula (1). It is particularly preferable to contain ~ 100 mol%.

  Using the composition for forming a silicon-containing film according to this embodiment, an insulating film containing silicon, carbon, oxygen, and hydrogen can be efficiently formed by, for example, chemical vapor deposition. Such an insulating film has a high resistance to hydrofluoric acid chemicals widely used in a cleaning process during a semiconductor manufacturing process, and thus has a feature of high processing resistance such as chemical resistance.

  Further, the composition for forming a silicon-containing film according to this embodiment has a content of elements other than silicon, carbon, oxygen, and hydrogen (hereinafter also referred to as “impurities”) of less than 10 ppb, and a moisture content. What is less than 100 ppm is preferable. A silicon-containing film formed by a chemical vapor deposition method using the composition for forming a silicon-containing film according to this embodiment has a low relative dielectric constant and excellent processing resistance, and is suitable as an insulating film.

1.2. Production method of organic silane compound The production method of the organic silane compound represented by the general formula (1) is not particularly limited. For example, the organic silane compound represented by the following general formula (2) and the following An example is a method in which an organosilane compound represented by the general formula (3) is subjected to a coupling reaction in the presence of a metal. As the metal, magnesium is usually used.

・・・・・（２）
（式中、Ｒ^１〜Ｒ^３は、同一または異なり、水素原子、炭素数１〜４のアルキル基、ビニル基、またはフェニル基を示し、Ｘはハロゲン原子を示し、aは０〜２の整数を示す。）

(2)
(Wherein R ^{1 to} R ³ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, X represents a halogen atom, and a represents an integer of 0 to 2) Is shown.)

・・・・・（３）
（式中、Ｒ^４は、同一または異なり、水素原子、炭素数１〜４のアルキル基、ビニル基、またはフェニル基を示し、Ｒ^５は炭素数１〜４のアルキル基、アセチル基、またはフェニル基を示し、Ｙはハロゲン原子、水素原子、またはアルコキシ基を示し、ｍは１〜２の整数を示す。）

(3)
Wherein R ⁴ is the same or different and represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, and R ⁵ is an alkyl group having 1 to 4 carbon atoms, an acetyl group, or phenyl. And Y represents a halogen atom, a hydrogen atom, or an alkoxy group, and m represents an integer of 1 to 2.)

In the general formula (2) and ^(3), the alkyl group having 1 to 4 carbon atoms represented by R 1 to R ^5, the number of carbon atoms represented by ^R 1 to R ⁵ in the general formula (1) 1 And the halogen atom represented by X and Y include, for example, a bromine atom and a chlorine atom, and the alkoxy group represented by Y represents the above general formula (1). those exemplified as the alkoxy group represented by -OR ⁵ and the like.

1.3. Pore-forming agent Examples of the pore-forming agent include compounds having a ring structure, preferably a compound having two or more rings in the molecule (polycyclic compound), more preferably a condensed ring. Examples thereof include polycyclic hydrocarbons or monocyclic hydrocarbons, and compounds containing a hetero atom (oxygen atom, nitrogen atom, or fluorine atom, preferably oxygen atom).

  In order to obtain an insulating film having a low relative dielectric constant and sufficient mechanical strength, the size and number of porous holes present in the insulating film are important, and factors determining the size of the porous holes One is the type of pore-forming agent used.

  In order to obtain an insulating film having a low relative dielectric constant and sufficient mechanical strength, the pore-forming agent is preferably a polycyclic compound, and the polycyclic compound is, for example, a 3-membered ring compound or a 4-membered ring A compound and / or a compound having a 7-membered ring structure or more, for example, an oxabicyclo compound such as cyclopentene oxide or bicycloheptadiene (BCHD).

  The silicon-containing film-forming composition according to this embodiment preferably contains 0.05 to 10,000 parts by weight of a pore-forming agent with respect to 100 parts by weight of the organosilane compound represented by the general formula (1). More preferably, it contains 0.1 to 5000 parts by weight of a pore-forming agent. In the silicon-containing film forming composition according to this embodiment, the dielectric constant is such that the content of the pore-forming agent is less than 0.05 with respect to 100 parts by weight of the organosilane compound represented by the general formula (1). In some cases, it is difficult to reduce the rate. On the other hand, if it exceeds 10,000 parts by weight, a uniform film may not be obtained. For example, a composition can be prepared by previously mixing a pore forming agent with the organosilicon compound, and a film can be formed by chemical vapor deposition using this composition.

1.3.1. Oxabicyclo Compound As the oxabicyclo compound, for example, 6-oxabicyclo [3.1.0] hexane (cyclopentene oxide), 7-oxabicyclo [4.1.0] heptane (cyclohexene oxide), 9-oxabicyclo [ 6.1.0] nonane (cyclooctene oxide), 7-oxabicyclo [2.2.1] heptane (1,4-epoxycyclohexane).

  In addition, examples of the oxabicyclo compound include compounds such as 9-oxabicyclo [6.1.0] non-4-ene. Further, the oxabicyclo compound is not limited, for example, 7-oxabicyclo [4.1.0] heptan-2-one or 3-oxabicyclo [3.1.0] hexane-2,4-dione. May be a compound having an additional functional group such as ketone, aldehyde, amine, amide, imide, ether, ester, anhydride, carbonate, thiol, or thioether.

1.3.2. Polycyclic hydrocarbon The polycyclic hydrocarbon preferably has 6 to 12 carbon atoms. For example, 2,5-norbomadiene (bicyclo [2.2.1] hepta-2,5-diene), norbomylene 2,5-norbornadiene (bicyclo [2.2.1] hepta-2,5-diene), norbornane (bicyclo [2.2.1] heptane), tricyclo [3.2.1.0] octane, tricyclo [ 3.2.2.0] Nonane, spiro [3.4] octane, spiro [4.5] nonane, spiro [5.6] decane and other bonded ring hydrocarbons.

1.3.3. Monocyclic hydrocarbon Examples of the monocyclic hydrocarbon include alicyclic hydrocarbons having 5 to 12 carbon atoms such as cyclopentane and cyclohexane, benzene, toluene, xylene (o-xylene, m-xylene, n -Xylene) and the like, and aromatic hydrocarbons having 6 to 12 carbon atoms.

2. Method for Forming Silicon-Containing Film A method for forming a silicon-containing film according to an embodiment of the present invention includes a step of forming a deposited film by chemical vapor deposition (CVD) using the silicon-containing film forming composition. Curing the deposited film.

  Moreover, it is preferable to perform especially the formation method of the silicon-containing film which concerns on this embodiment by plasma excitation CVD method (PECVD method). In the PECVD apparatus, the organosilane compound represented by the general formula (1) is vaporized by a vaporizer, introduced into a film forming chamber, and applied to an electrode in the film forming chamber by a high frequency power source to generate plasma. By doing so, a plasma CVD film can be formed on the substrate in the deposition chamber.

Examples of the substrate on which the silicon-containing film is formed include Si-containing layers such as Si, SiO ₂ , SiN, SiC, and SiCN. At this time, a gas such as argon or helium, or an oxidant such as oxygen or nitrous oxide can be introduced into the film formation chamber for the purpose of generating plasma. By forming a film with a PECVD apparatus, a thin film (deposited film) suitable as a low dielectric constant material for a semiconductor device can be formed.

  The plasma generation method of the PECVD apparatus is not particularly limited, and for example, inductively coupled plasma, capacitively coupled plasma, ECR plasma, or the like can be used.

  The film thickness of the silicon-containing deposited film thus obtained is preferably 0.05 to 5.0 μm. Thereafter, the silicon-containing film can be formed by subjecting the obtained deposited film to a curing treatment.

  The step of curing the deposited film is preferably performed by at least one curing process selected from heating, electron beam irradiation, ultraviolet irradiation, and oxygen plasma. By these hardening treatments, the pore-forming agent in the deposited film is decomposed, whereby the resulting silicon-containing film can be efficiently made porous. Thereby, an insulating film having a low relative dielectric constant (relative dielectric constant of 2.7 or less (usually 1.8 to 2.7)) can be obtained. It is more preferable to use heating and ultraviolet irradiation in the curing treatment in that the pore forming agent can be efficiently decomposed and an insulating film having excellent mechanical strength can be obtained.

  When curing is performed by heating, for example, a deposited film formed by chemical vapor deposition is heated to 80 ° C. to 450 ° C. under an inert atmosphere or under reduced pressure. As a heating method at this time, a hot plate, an oven, a furnace, or the like can be used, and a heating atmosphere can be performed under an inert atmosphere or under reduced pressure. The heating temperature is preferably 150 to 450 ° C. in that the pore-forming agent can be efficiently decomposed and an insulating film excellent in mechanical strength and chemical resistance can be obtained.

  Further, in order to control the curing rate of the deposited film, it is possible to heat it stepwise or to select an atmosphere such as nitrogen, air, oxygen, or reduced pressure as necessary. Through the above steps, a silicon-containing film can be formed.

3. Silicon-containing film A silicon-containing film according to an embodiment of the present invention can be obtained by the above-described forming method.

  Since the silicon-containing film according to this embodiment has a low dielectric constant and excellent surface flatness, it is particularly excellent as an interlayer insulating film for semiconductor elements such as LSI, system LSI, DRAM, SDRAM, RDRAM, and D-RDRAM. Also suitable for etching stopper film, protective film such as surface coating film of semiconductor element, intermediate layer of semiconductor manufacturing process using multilayer resist, interlayer insulating film of multilayer wiring board, protective film and insulating film for liquid crystal display element Can be used. In addition, the silicon-containing film according to the present embodiment is suitable for a semiconductor device formed by, for example, a copper damascene process.

Since the silicon-containing film according to the present embodiment is formed using the silicon-containing film-forming composition, the —Si— (CH ₂ ) _n —Si—O— site (where n is an integer of 1 to 3). Can be included). Since the silicon-containing film according to the present embodiment has the above-described site, it has excellent drug resistance and can suppress an increase in relative dielectric constant during processing, and thus has a low relative dielectric constant and excellent processing resistance. .

  The relative dielectric constant of the silicon-containing film according to this embodiment is preferably 3.0 or less, more preferably 1.8 to 3.0, and still more preferably 2.2 to 3.0.

  The elastic modulus of the silicon-containing film according to this embodiment is preferably 4.0 to 15.0 GPa, more preferably 4.0 to 12.0 GPa, and the hardness is preferably 0.1 GPa or more, More preferably, it is 0.5 GPa or more. From these, it can be said that the silicon-containing film according to the present embodiment is extremely excellent in insulating film characteristics such as mechanical strength and relative dielectric constant.

4). EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples. In the examples and comparative examples, “parts” and “%” indicate parts by weight and% by weight, respectively, unless otherwise specified.

4.1. Evaluation method Various evaluations were performed as follows.

4.1.1. Impurity Content in Organosilane Compound Water content and impurity content in the purified organosilane compound were measured using a Karl Fischer moisture meter (Hiranuma Sangyo Co., Ltd., trace moisture analyzer AQ-7) and atomic absorption spectrophotometer (Hitachi High-Tech). It was measured using a polarization Zeeman atomic absorption spectrophotometer Z-5700).

4.1.2. Measurement of relative dielectric constant A silicon-containing film was formed on an 8-inch silicon wafer by PECVD under the conditions described later. An aluminum electrode pattern was formed on the obtained film by a vapor deposition method, and a sample for measuring relative permittivity was prepared. With respect to the sample, the relative dielectric constant of the insulating film was measured at a frequency of 100 kHz by the CV method using an HP16451B electrode and an HP4284A precision LCR meter manufactured by Yokogawa Hewlett-Packard Co., Ltd. Δk is the difference between the relative dielectric constant (k @ RT) measured in an atmosphere of 24 ° C. and 40% RH and the relative dielectric constant (k @ 200 ° C.) measured in an atmosphere of 200 ° C. and dry nitrogen (Δk = k @ RT-k @ 200 ° C.). With this Δk, it is possible to mainly evaluate the increase in relative dielectric constant due to moisture absorption of the film. Usually, when Δk is 0.15 or more, it can be said that the organic silica film has high water absorption.

4.1.3. Evaluation of Hardness and Elastic Modulus (Young's Modulus) of Insulating Film A Berkovich indenter was attached to an ultra-small hardness meter (Nanoindenter XP) manufactured by MTS, and the universal hardness of the obtained insulating film was determined. The elastic modulus was measured by a continuous stiffness measurement method.

4.1.4. Storage stability The purity of the organosilane compound stored at 40 ° C. for 30 days was determined by GC (apparatus body: 6890N manufactured by Agilent Technologies, column: SPB-35 manufactured by Supelco). If the purity change before and after storage is less than 0.5%, it is judged that the storage stability is good.

4.1.5. Chemical Solution Resistance An 8-inch wafer on which a silicon-containing film was formed was immersed in a 0.2% dilute hydrofluoric acid aqueous solution at room temperature for 3 minutes, and the change in film thickness of the silicon-containing film before and after immersion was observed. If the remaining film rate defined below is 99% or more, it is judged that the chemical resistance is good.
Remaining film ratio (%) = (film thickness after immersion) / (film thickness before immersion) × 100
A: The remaining film rate is 99% or more.
B: The remaining film rate is less than 99%.

4.2. Production of film forming material 4.2.1. Synthesis example 1
A three-necked flask equipped with a cooling condenser and a dropping funnel was dried at 50 ° C. under reduced pressure, and then charged with nitrogen. Next, 20 g of magnesium and 500 ml of THF were added to the flask, and 25 g of (chloromethyl) trimethylsilane was added with stirring at room temperature. After stirring for a while and confirming heat generation, 55 g of (chloromethyl) trimethylsilane was added from a dropping funnel over 30 minutes. After the completion of the dropwise addition, after confirming that the liquid temperature had returned to room temperature, a mixture of 250 ml of THF and 237 g of methyltrimethoxysilane was added to the flask, followed by heating to reflux at 70 ° C. for 6 hours to complete the reaction. It was. After cooling the reaction solution to room temperature, the produced magnesium salt and unreacted magnesium were filtered off, and the filtrate was fractionated to obtain 75 g of [(trimethylsilyl) methyl] methyldimethoxysilane (hereinafter referred to as “Compound A”). (Yield 60%). The purity obtained by the GC method was 99.4%.

4.2.2. Synthesis example 2
A three-necked flask equipped with a cooling condenser and a dropping funnel was dried at 50 ° C. under reduced pressure, and then charged with nitrogen. Next, 20 g of magnesium and 500 ml of THF were added to the flask, and 25 g of (chloromethyl) trimethylsilane was added with stirring at room temperature. After stirring for a while and confirming heat generation, 55 g of (chloromethyl) trimethylsilane was added from a dropping funnel over 30 minutes. After the completion of the dropwise addition, after confirming that the liquid temperature had returned to room temperature, a mixture of 250 ml of THF and 258 g of vinyltrimethoxysilane was added to the flask, followed by heating to reflux at 70 ° C. for 6 hours to complete the reaction. It was. After cooling the reaction solution to room temperature, the produced magnesium salt and unreacted magnesium were filtered off, and the filtrate was subjected to fractional distillation to give 80 g of [(trimethylsilyl) methyl] vinyldimethoxysilane (hereinafter referred to as “Compound B”). (Yield 60%). The purity obtained by the GC method was 99.1%.

4.2.3. Synthesis example 3
A three-necked flask equipped with a cooling condenser and a dropping funnel was dried at 50 ° C. under reduced pressure, and then charged with nitrogen. Next, 500 ml of toluene was added to the flask, and 129 g of ethyldichlorosilane and 142 g of vinyltriethylsilane were added while stirring at room temperature. The mixture was stirred for a while, and 100 mg of chloroplatinic acid was added thereto and reacted at 100 ° C. for 5 hours. After cooling this to room temperature, 160 g of pyridine was added dropwise while adding 160 g of pyridine and stirring. After the dropwise addition and reaction at room temperature for 3 hours, the formed salt was filtered off and the filtrate was subjected to fractional distillation to give 180 g of [(triethylsilyl) ethyl] ethyldiethoxysilane (hereinafter referred to as “Compound C”. Yield 62) %). The purity obtained by the GC method was 99.2%.

4.3. Formation of film 4.3.1. Examples and Comparative Examples A film forming composition containing an organosilicon compound and a pore-forming agent in the proportions shown in Table 1 below was prepared using a dual frequency plasma CVD apparatus manufactured by UTEC. The plasma CVD conditions are as follows: the gas flow rate of the silicon-containing film forming composition is 0.3 sccm, the Ar gas flow rate is 100 sccm, the RF upper showerhead power is 300 W (27.12 MHz), the lower substrate power is 150 W (380 kHz), and the substrate temperature. A silicon-containing film of 0.5 μm was formed on a silicon substrate at 300 ° C. and a reaction pressure of 10 Torr.

  In Examples 7-8 and Comparative Example 4, after film formation by plasma CVD, ultraviolet rays were applied while heating the coating film at 400 ° C. on a hot plate in a chamber having an oxygen partial pressure of 0.01 kPa. Irradiated. As the ultraviolet light source, white ultraviolet light having a wavelength of 250 nm or less was used. Since this ultraviolet light is white ultraviolet light, the illuminance cannot be measured by an effective method.

  Table 1 shows the evaluation results of the silicon-containing films obtained in Examples and Comparative Examples.

  The silicon-containing film obtained in Example 1-8 was excellent in mechanical strength, low Δk, which is an index indicating the relative permittivity and hygroscopicity, and was also excellent in chemical resistance.

  Specifically, the silicon-containing film obtained in Example 1-8 has a lower relative dielectric constant than the film obtained in Comparative Example 1-4. This shows that a film having a low relative dielectric constant can be obtained by forming a film by CVD using an organosilicon compound together with a pore-forming agent.

  Furthermore, in Examples 7 and 8, after film formation by plasma CVD, the film was irradiated with ultraviolet rays. Since the films obtained in Examples 7 and 8 have higher mechanical strength than the films obtained in Examples 1 and 2, it is possible to further increase the mechanical strength of the film by ultraviolet irradiation. I understand.

  Comparative Example 5-7 is an example in which a compound having no Si—C—Si bond and Si—C—C—Si bond was used as the organosilicon compound, but was obtained in Comparative Example 5-7. It can be seen that the film is inferior in chemical resistance of the film regardless of whether or not a pore-forming agent is used.

  As described above, the silicon-containing film according to the present invention is excellent in mechanical strength, has a low relative dielectric constant, and is excellent in moisture absorption resistance and chemical resistance. be able to.

Claims (3)

A silicon-containing film-forming composition comprising an organosilane compound represented by the following general formula (1) and a pore-forming agent.

(1)
(Wherein R ^{1 to} R ⁴ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, and R ⁵ represents an alkyl group having 1 to 4 carbon atoms or an acetyl group. Or n represents an integer of 1 to 3, and m represents an integer of 1 to 2.)   The composition for forming a silicon-containing film according to claim 1, comprising 0.05 to 10,000 parts by weight of the pore forming agent with respect to 100 parts by weight of the organosilane compound.   The composition for forming a silicon-containing film according to claim 1 or 2, which is used for film formation by chemical vapor deposition.