Alkoxysilacyclic or acyloxysilacyclic compound and method for depositing film using same

Abstract

A method and composition for preparing a porous low-k dielectric film by chemical vapor deposition is provided. In one aspect, the method includes the steps of: providing a substrate within a reaction chamber; introducing a gas reagent into the reaction chamber, the gas reagent comprising at least one structure-forming precursor with or without a pore-forming agent, the structure-forming precursor comprising an alkoxysilacyclic or acyloxysilacyclic compound; applying energy to the gas reagent in the reaction chamber to induce a reaction of the gas reagent to deposit an initial film on the substrate, where the initial film comprises the pore former, and the initial film is deposited; and removing at least a portion of the pore former contained therein from the initial film, and providing pores and a dielectric constant of 3.2 or less to the film. In certain embodiments, the structure-forming precursor further comprises a hardening additive.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880056914.6, filed August 29, 2018, entitled “Alkoxy-silacyclic or Acyloxy-silacyclic Compounds and Methods of Depositing Films Using the Same,” which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62 / 552,040, filed August 30, 2017, the entire contents of which are incorporated herein by reference. Cross Reference to Related Applications

[0002] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62 / 552,040, filed August 30, 2017, the entire contents of which are incorporated herein by reference. BACKGROUND

[0003] Described herein are compositions and methods for forming dielectric films using alkoxy-silacyclic or acyloxy-silacyclic compounds as structure-forming precursors. More specifically, described herein are compositions and methods for forming porous low dielectric constant films (“low-k” films or films having a dielectric constant of about 3.2 or less), wherein the method for depositing the films is a chemical vapor deposition (CVD) method. The low dielectric films produced by the compositions and methods described herein can be used as, for example, insulating layers in electronic devices.

[0004] The electronics industry utilizes dielectric materials as insulating layers between the circuits and components of integrated circuits (ICs) and related electronic devices. To increase the speed and memory storage capability of microelectronic devices, such as computer chips, line sizes are being reduced. As line sizes are reduced, the insulating requirements for interlayer dielectrics (ILDs) become much more stringent. Shrinking the pitch requires lower dielectric constants to minimize the RC time constant, where R is the resistance of the conducting line and C is the capacitance of the insulating dielectric interlayer. Capacitance (C) is inversely proportional to pitch and directly proportional to the dielectric constant (k) of the interlayer dielectric (ILD). Conventional silicon dioxide (Si02) CVD dielectric films prepared from SiH4or TEOS (Si(OCH2CH3)4, tetraethyl orthosilicate) and 02have a dielectric constant k greater than 4.0. There are a number of ways in which the industry has attempted to prepare silicon-based CVD films with lower dielectric constants, the most successful being to dope the insulating silicon oxide film with organic groups, thereby providing a dielectric constant ranging from about 2.7 to about 3.5. This organosilicon glass is typically deposited as a dense film (density ~ 1.5 g / cm3) from an organosilicon precursor, such as methylsilane or siloxane, and an oxidant, such as 02or N20. The organosilicon glass is referred to herein as OSG. As the dielectric constant or “k” value is lowered below 2.7 with higher device densities and smaller sizes, the industry has exhausted most of the low-k compositions suitable for dense films and has moved to various porous materials for improved insulating properties. 3

[0005] ​Patents, published applications, and publications in the field of making porous ILDs by CVD methods include: EP 1 119 035 A2 and U.S. Patent No. 6,171,945, which describe a method of depositing an OSG film from a silicon-containing precursor having labile groups in the presence of an oxidizing agent (e.g., N2O, and optionally, peroxide), followed by removal of the labile groups by thermal annealing to provide a porous OSG; U.S. Patent Nos. 6,054,206 and 6,238,751, which teach removal of substantially all organic groups from a deposited OSG by oxidative annealing to obtain a porous inorganic SiO2; EP 1 037 275, which describes deposition of a hydrogenated silicon carbide film, which is converted to a porous inorganic SiO2by subsequent treatment with an oxidizing plasma; and U.S. Patent No. 6,312,793 Bl, WO 00 / 24050, and the literature article Grill, A. Patel, V. Appl. Phys. Lett. (2001 ), 79(6), pp. 803-805, which all teach co-deposition of a film from an organosilicon precursor and an organic compound, and subsequent thermal annealing to provide a heterogeneous OSG / organic film, in which a portion of the polymeric organic component is retained. In the latter reference, the final product composition of the film indicates a residual pore-forming agent and a high hydrocarbon film content of about 80 to 90 atomic %. Furthermore, the final film retains a SiO2-like network, in which a portion of the oxygen atoms are replaced by organic groups.

[0006] One challenge recognized in the industry is that films with lower dielectric constants generally have higher porosities, which results in enhanced diffusion of species into the film, particularly gas phase diffusion. This increased diffusion can result in increased removal of carbon from the porous OSG film during processes such as etching of the film, plasma ashing of photoresist, and NH3plasma treatment of copper surfaces. Carbon depletion in the OSG film can result in one or more of the following problems: an increase in the dielectric constant of the film; film etching and feature bowing during a wet clean step; wet vapor absorption into the film due to loss of hydrophobicity, pattern collapse of fine features during a wet clean step after pattern etching, and / or integration problems when depositing subsequent layers such as, but not limited to, copper diffusion barrier layers such as Ta / TaN or advanced Co or MnN barrier layers.

[0007] A possible solution to one or more of these issues is to use a porous OSG film with increased carbon content. A first approach is to use a porogen that results in higher retention of Si-methyl (Me) groups in the porous OSG layer. Unfortunately, increasing the Si-Me content typically results in decreased mechanical properties, so a film with more Si-Me will negatively impact mechanical strength, which is important for integration. A second approach is to use a damage resistant porogen (DRP), for example, the porogen disclosed in U.S. Patent No. 8,753,985, which leaves additional amorphous carbon in the film after UV curing. In some cases, this residual carbon does not negatively impact the dielectric constant and mechanical strength. However, it is difficult to achieve significantly higher carbon content in these films using DRPs.

[0008] Another proposed solution is to use ethylene or methylene bridged disiloxanes of the general formula R x (RO) 3-x Si(CH2) y SiR z (OR) 3-z where x = 0-3, y = 1 or 2, and z = 0-3. The use of bridged species is believed to avoid negative impacts on mechanical properties by replacing bridging oxygen with a bridging carbon chain, as network connectivity will remain the same. This is believed to be because replacing bridging oxygen with a terminal methyl group will decrease mechanical strength by decreasing network connectivity. In this way, it is possible to replace an oxygen atom with 1-2 carbon atoms to increase the carbon atomic weight percent (%) without decreasing mechanical strength. However, these bridged precursors typically have very high boiling points due to the increased molecular weight with two silicon groups. The increased boiling point can negatively impact the manufacturing process by making it difficult to deliver the chemical precursor as a gas phase reagent into the reaction chamber without condensing it in the vapor delivery lines or process pump exhaust.

[0009] Accordingly, there is a need in the art for dielectric precursors that provide a film with increased carbon content after deposition, but without the drawbacks described above. SUMMARY

[0010] The methods and compositions described herein satisfy one or more of the needs described above. The methods and compositions described herein use an alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compound, such as 1,1-dimethoxy-1-silacyclopentane (DMSCP) or 1,1-diethoxy-1-silacyclopentane (DESCP), as a structure forming precursor that, upon co-deposition with a pore former precursor and upon UV curing to remove the pore former and harden the film so deposited, provides a porous low-k dielectric film having similar mechanical properties to films using prior art structure forming precursors, such as diethoxymethylsilane (DEMS), at the same dielectric constant. In addition, films deposited using the alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compounds described herein as structure forming precursors contain a relatively high amount of carbon. In addition, the alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compounds described herein have a lower molecular weight (Mw) relative to other prior art structure forming precursors, such as bridged precursors (e.g., methylene or ethylene bridged ethysilane or disiloxane precursors), which have a higher Mw and higher boiling point due to having 2 silicon groups, making the alkoxy silyl heterocyclic or acyloxy silyl heterocyclic precursors described herein more amenable to, for example, processing in high volume manufacturing processes.

[0011] Described herein are porous dielectric films comprising: a material represented by the formula: v O w C x H y F z wherein v + w + x + y + z = 100%, v is 10 to 35 atomic %, w is 10 to 65 atomic %, x is 5 to 45 atomic %, y is 10 to 50 atomic %, and z is 0 to 15 atomic %, wherein the film has pores with a volume porosity of 5.0 to 30.0%, a dielectric constant of 2.3 to 3.2, and mechanical properties such as a hardness of 1.0 to 7.0 and an elastic modulus of 4.0 to 40.0. In certain embodiments, the film contains a higher carbon content (10-40%) as measured by X-ray photoelectron spectroscopy (XPS) and exhibits a reduced carbon removal depth when exposed to, for example, O2 or NH3 plasma as measured by examining the carbon content determined by XPS depth profiling.

[0012] In one aspect, there is provided a composition for vapor deposition of a dielectric film comprising an alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compound having the following formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R 3 , R 1-3each independently selected from the group consisting of linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl and C3to C 10 heteroaryl; and R 4 is a C3to C5alkyldiyl forming a four-, five-, or six-membered saturated cyclic ring with the Si atom, and wherein the compound is substantially free of one or more impurities selected from the group consisting of halides and water.

[0013] In another aspect, a chemical vapor deposition method for making a porous dielectric film is provided, comprising: providing a substrate within a reaction chamber; introducing a gas reagent into the reaction chamber, wherein the gas reagent comprises a structure-forming precursor comprising an alkoxy-silacyclic or acyloxy-silacyclic compound having the following Formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R 3 , R 1-3 each independently selected from the group consisting of linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl and C3to C 10 heteroaryl; and R 4 is a C3to C5alkyldiyl forming a four-, five-, or six-membered saturated cyclic ring with the Si atom, and optionally, at least one pore-forming agent; applying energy to the gas reagent in the reaction chamber to induce a reaction of the gas reagent to deposit an initial film on the substrate, wherein the initial film comprises a pore-forming agent; and removing substantially all of the pore-forming agent from the initial film to provide a porous film having pores and a dielectric constant of less than 3.2. In certain embodiments, the structure-forming precursor further comprises a hardening additive.

[0014] In another aspect, a chemical vapor deposition method for making a porous dielectric film is provided, comprising: providing a substrate within a reaction chamber; introducing a gas reagent into the reaction chamber, wherein the gas reagent comprises: a structure forming precursor comprising an alkoxy silacyclic or acyloxy silacyclic compound having the following Formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R 3 , each R 1-3 is independently selected from the group consisting of linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl, and C3to C 10 heteroaryl; and R 4 is a C3to C5alkyldiyl forming a four-, five-, or six-membered saturated cyclic ring with the Si atom, optionally, at least one oxygen source, and optionally, at least one porogen; and applying energy to the gas reagent in the reaction chamber to induce a reaction of the gas reagent to deposit an initial film on the substrate, wherein the initial film comprises a porogen; and removing substantially all of the porogen from the initial film to provide a porous film having pores and a dielectric constant of less than 3.2. In certain embodiments, the structure forming precursor further comprises a hardening additive.

[0015] Embodiments and features of the present invention can be used alone or in combination with each other. DETAILED DESCRIPTION

[0016] Described herein is a chemical vapor deposition (CVD) method for producing a porous low-k dielectric film, comprising: providing a substrate within a reaction chamber; introducing a gas reagent into the reaction chamber, the gas reagent comprising at least one structure forming precursor comprising an alkoxy silacyclic or acyloxy silacyclic compound, for example, 1,1-dimethoxy-1-silacyclopentane or 1,1-diethoxy-1-silacyclopentane, and a porogen; applying energy to the gas reagent in the reaction chamber to induce a reaction of the gas reagent to deposit an initial film on the substrate, wherein the initial film comprises a porogen and an organosilicate glass; and removing substantially all of the porogen from the initial film to provide a porous film having pores and a dielectric constant of less than 3.2.

[0017] The alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compounds described herein provide unique attributes that make it possible to introduce more carbon content in the dielectric film with little impact on the mechanical properties of the dielectric film compared to prior art structure forming precursors such as diethoxymethylsilane (DEMS). For example, DEMS provides a mixed ligand system with two alkoxy groups, one methyl group, and one hydride in the DEMS that provides a balance of reactive sites and allows for the formation of a mechanically more robust film while maintaining the desired dielectric constant. The use of alkoxy silyl heterocyclic or acyloxy silyl heterocyclic compounds provides the following advantages: there are no terminal methyl groups in the precursor that tend to decrease mechanical strength, and the carbons in the silyl heterocyclic ring provide cardogn to the OSG film to lower the dielectric constant and add hydrophobicity.

[0018] Low-k dielectric films are organosilicate glass ("OSG") films or materials. Organosilicates are candidates for low-k materials, but their intrinsic dielectric constant will be limited to as low as 3.2 without the addition of pore formers to increase the porosity of these materials. Increases in porosity, where the void space has an intrinsic dielectric constant of 1.0, decrease the overall dielectric constant of the film, often at the expense of mechanical properties. Material performance depends on the chemical composition and structure of the film. Since the type of organosilicon precursor has a strong influence on the structure and composition of the film, it is beneficial to use a precursor that provides the desired film properties to ensure that increasing the desired amount of porosity to achieve the desired dielectric constant does not produce a mechanically unsuitable film. The methods and compositions described herein provide a means to produce porous low-k dielectric films with the desired balance of electrical and mechanical properties as well as other beneficial film properties such as high carbon content that provide improved integrated plasma resistance.

[0019] In certain embodiments of the methods and compositions described herein, a layer of a silicon-containing dielectric material is deposited on at least a portion of a substrate by a chemical vapor deposition (CVD) process employing a reaction chamber. Suitable substrates include, but are not limited to, semiconductor materials such as gallium arsenide ("GaAs"), silicon, and compositions containing silicon (e.g., crystalline silicon, polycrystalline silicon, amorphous silicon, epitaxial silicon, silicon dioxide ("Si02"), silicon glass, silicon nitride, fused silica, glass, quartz, borosilicate glass, and combinations thereof). Other suitable materials include chromium, molybdenum, and other metals commonly used in semiconductor, integrated circuit, flat panel display, and flexible display applications. The substrate can have additional layers, for example, silicon, Si02, organosilicate glass (OSG), fluorinated silicate glass (FSG), boron carbonitride, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, boron nitride, organic-inorganic composites, photoresists, organic polymers, porous organic and inorganic materials and composites, metal oxides such as aluminum oxide and germanium oxide. Still further layers can also be germanosilicates, aluminosilicates, copper and aluminum, and diffusion barrier materials such as, but not limited to, TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN.

[0020] In certain embodiments, the layer of silicon-containing dielectric material is deposited on at least a portion of a substrate by introducing into a reaction chamber a gaseous reagent comprising at least one structure-forming precursor comprising an alkoxy-silacyclic or acyloxy-silacyclic compound, with or without a pore former precursor. In another embodiment, the layer of silicon-containing dielectric material is deposited on at least a portion of a substrate by introducing into a reaction chamber a gaseous reagent comprising at least one structure-forming precursor comprising an alkoxy-silacyclic or acyloxy-silacyclic compound, and a hardening additive.

[0021] The methods and compositions described herein use an alkoxy-silacyclic or acyloxy-silacyclic compound having the following Formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(0)R 3 , wherein R 1-3 each independently is selected from the group consisting of linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl, and C3to C 10 heteroaryl; and R 4C3to C5alkyldiyl that forms a four-, five-, or six-membered saturated cyclic ring with the Si atom.

[0022] In the above formula I and throughout the specification, the term "alkyl" means a straight chain or branched chain functional group having 1 to 10 carbon atoms. Exemplary straight chain alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, butyl, pentyl, and hexyl. Exemplary branched alkyl groups include, but are not limited to, isopropyl, isobutyl, sec-butyl, t-butyl, isopentyl, t-pentyl, isohexyl, and neohexyl. In certain embodiments, the alkyl group can have one or more functional groups attached thereto, such as, but not limited to, an alkoxy group attached thereto, such as methoxy, ethoxy, isopropoxy, and n-propoxy, a dialkylamino group, such as dimethylamino, or a combination thereof. In other embodiments, the alkyl group does not have one or more functional groups attached thereto. The alkyl group can be saturated or unsaturated.

[0023] In the above formula I and throughout the specification, the term "cyclic alkyl" means a cyclic functional group having 3 to 10 carbon atoms. Exemplary cyclic alkyl groups include, but are not limited to, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl.

[0024] In the above formula I and throughout the specification, the term "heterocycle" means a C3to C 10 heterocyclic alkyl, such as an epoxy group.

[0025] In the above formula I and throughout the specification, the term "alkenyl" means a group having one or more carbon-carbon double bonds and having 2 to 10 or 2 to 10 or 2 to 6 carbon atoms.

[0026] In the above formula I and throughout the specification, the term "alkynyl" means a group having one or more carbon-carbon triple bonds and having 3 to 10 or 2 to 10 or 2 to 6 carbon atoms.

[0027] In the above formula I and throughout the specification, the term "aryl" means an aromatic cyclic functional group having 5 to 10 carbon atoms or 6 to 10 carbon atoms. Exemplary aryl groups include, but are not limited to, phenyl, benzyl, chlorobenzyl, tolyl, and o-tolyl.

[0028] In the above formula I and throughout the specification, the term "heteroaryl" means a C3to C 10 heterocyclic aryl 1,2,3-triazolyl, pyrrolyl, and furanyl.

[0029] In certain embodiments, one or more chemical moieties of Formula I or otherwise described herein can be "unsubstituted" or "substituted." As used herein, a "substituted" atom or moiety indicates that any hydrogen atom on the designated compound or moiety can be replaced with a selection from the group of substituents indicated, provided that the substituents result in a stable compound, that the normal valence of the designated compound or moiety is not exceeded, and that the substitution results in a stable compound. For example, if a methyl group is optionally substituted, then 1, 2, or 3 of the hydrogen atoms on the carbon atom of the methyl group can be replaced with 1, 2, or 3 of the recited substituents.

[0030] In Formula I above, the substituent R 4 is a C3to C 10 alkyl diradical that forms a four-, five-, or six-membered cyclic ring with the Si atom. As understood by one of skill in the art, R 4 is a substituted or unsubstituted hydrocarbon chain that is connected together with a silicon atom to form a ring in Formula I, wherein the ring is a four-, five-, or six-membered ring. In these embodiments, the ring structure can be a saturated ring, such as a cycloalkyl ring. Exemplary saturated rings include, but are not limited to, silacyclbutane, silacyclopentane, and silacyclohexane, preferably silacyclopentane, or a silacyclopentane substituted with an alkyl group such as methyl.

[0031] Throughout the specification, the term "alkoxysilacyclic ring" refers to a compound having at least one Si-alkoxy group and one cyclic ring having one silicon atom and no carbon-carbon double bonds.

[0032] Throughout the specification, the term "acyloxysilacyclic ring" refers to a compound having at least one Si-acyloxy group and one cyclic ring having one silicon atom and no carbon-carbon double bonds.

[0033] Throughout the specification, the term "oxygen source" refers to a gas comprising oxygen (O2), a mixture of oxygen and helium, a mixture of oxygen and argon, nitrous oxide (N2O), nitric oxide (NO), carbon dioxide, carbon monoxide, and mixtures thereof.

[0034] Throughout the specification, the term "dielectric film" refers to a film having a composition of Si v O w C x H y F z wherein v + w + x + y + z = 100%, v is from 10 to 35 atomic %, w is from 10 to 65 atomic %, x is from 5 to 40 atomic %, y is from 10 to 50 atomic %, and z is from 0 to 15 atomic %.

[0035] In certain embodiments of Formula I, R 1 is selected from the group consisting of methyl and ethyl, R 2 is selected from the group consisting of methyl, ethyl, and isopropyl, and R4 tetra-, penta-, or hexa-saturated cyclic rings with Si atoms. In some embodiments, the tetra-, penta-, or hexa-saturated cyclic rings with Si atoms can have at least one alkyl substituent, such as a methyl group on the ring structure. Examples of these embodiments are as follows:

[0036] In some embodiments, the compositions and methods described herein use an alkoxy- or acyloxy-silacyclic compound, 1,1-dimethoxysilacyclopentane (DMSCP) or 1,1-diethoxysilacyclopentane (DESCP) or 1,1-diacetoxy-1-silacyclopentane as a structure forming precursor, which has the following structure: The alkoxy- or acyloxy-silacyclic compounds described herein and methods and compositions comprising the same are preferably substantially free of one or more impurities, such as, but not limited to, halide ions and water. As used herein, the term "substantially free of" when it refers to each impurity means 100 parts per million (ppm) or less, 50 ppm or less, 10 ppm or less, and 5 ppm or less, 1 ppm or less of each impurity, such as, but not limited to, chloride or water.

[0037] In some embodiments, the alkoxy- or acyloxy-silacyclic compounds according to the present application and compositions comprising the compounds of Formula I according to the present application are preferably substantially free of halide ions. As used herein, the term "substantially free of" when it refers to halide ions (or halides), such as, but not limited to, chloride (i.e., chlorine-containing species, such as HC1, or silicon compounds with at least one Si-Cl bond, such as silicon tetrachloride, dichlorodiethoxysilane) and fluoride, bromide, and iodide means less than 5 ppm (by weight) as measured by ICP-MS, preferably less than 3 ppm as measured by ICP-MS, and more preferably less than 1 ppm as measured by ICP-MS, most preferably 0 ppm as measured by ICP-MS. Chloride is known to act as a decomposition catalyst for the compounds of Formula I. Significant levels of chloride in the final product can lead to degradation of the silicon precursor compound. Gradual degradation of the alkoxy- or acyloxy-silacyclic compounds can directly impact the film deposition process, making it difficult for semiconductor manufacturers to meet film specifications. Furthermore, higher rates of degradation of the alkoxy- or acyloxy-silacyclic compounds negatively impact shelf life or stability, making it difficult to guarantee a shelf life of 1-2 years. The alkoxy- or acyloxy-silacyclic compounds of Formula I are preferably substantially free of metal ions, such as, but not limited to, Li+ Na + K + Mg 2+ Ca 2+ Al 3+ Fe 2+ Fe 2+ Fe 3+ Ni 2+ Cr 3+ As used herein, the term "substantially free" when it refers to Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr, refers to less than 5 ppm by weight, preferably less than 3 ppm, more preferably less than 1 ppm, most preferably 0.1 ppm, as measured by ICP-MS. In some embodiments, the alkoxy silacyclic or acyloxy silacyclic compounds of Formula I are free of metal ions, for example, Li + Na + K + Mg 2+ Ca 2+ Al 3+ Fe 2+ Fe 2+ Fe 3+ Ni 2+ Cr 3+ As used herein, the term "free" of metal impurities when it refers to Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr, noble metals such as volatile Ru or Pt complexes from ruthenium or platinum catalysts used in the synthesis, refers to less than 1 ppm, preferably 0.1 ppm by weight, as measured by ICP-MS or other analytical methods for measuring metals.

[0038] The compositions according to the present application that are substantially free of halides can be achieved by (1) reducing or eliminating chloride sources during chemical synthesis, and / or (2) implementing effective purification processes to remove chlorides from the crude product, such that the final purified product is substantially free of chlorides. Chloride sources can be reduced during synthesis by using reagents that are free of halides such as chloroethylsilane, bromoethylsilane, or iodoethylsilane, thereby avoiding the production of byproducts containing halide ions. Furthermore, the aforementioned reagents should be substantially free of chloride impurities, such that the resulting crude product is substantially free of chloride impurities. In a similar manner, the synthesis should not use halide-based solvents, catalysts, or solvents containing unacceptably high levels of halide contamination. The crude product can also be treated by various purification methods to render the final product substantially free of halides, such as chlorides. Such methods are well described in the prior art, and can include, but are not limited to, distillation or adsorption purification treatments. Distillation is commonly used to separate desired products from impurities by taking advantage of boiling point differences. Adsorption can also be used to take advantage of different adsorptive properties of components to achieve separation, such that the final product is substantially free of halides. Adsorbents, such as commercially available MgO-Al2O3mixtures, can be used to remove halides such as chlorides.

[0039] In view of the prior art silicon-containing structure forming precursors, such as DEMS, which polymerize upon the supply of energy in the reaction chamber to form structures having -0- linkages (e.g., -Si-0-Si- or -Si-0-C-) in the polymer backbone, it is believed that the alkoxysilacyclic or acyloxysilacyclic compounds, such as the MESCAP molecules, polymerize to form structures in which some of the -0- bridges in the backbone are replaced by -CH2- methylene or -CH2CH2- ethylene bridges. In films deposited using DEMS as the structure forming precursor, in which carbon is present primarily in the form of terminal Si-Me groups, there is a relationship between the % Si-Me (directly related to % C) and mechanical strength, in which replacing bridging Si-0-Si groups with two terminal Si-Me groups reduces mechanical properties because the network structure is disrupted. In the case of the alkoxysilacyclic or acyloxysilacyclic compounds, it is believed that the ring structure is disrupted during film deposition or curing (to remove at least a portion or substantially all of the pore former precursor contained in the film so deposited) to form SiCH2Si or SiCH2CH2Si bridging groups. In this manner, carbon can be introduced in the form of bridging groups such that the network structure is not disrupted by increasing the carbon content of the film from a mechanical strength perspective. Without intending to be bound by a particular theory, it is believed that this attribute adds carbon to the film that allows the film to be more resilient to carbon depletion of the porous OSG film from processes such as etching of the film, plasma ashing of photoresist, and NH3 plasma treatment of copper surfaces. Carbon depletion in the OSG film can result in an increase in the defective dielectric constant of the film, as well as problems with film etching and feature bowing during wet clean steps, and / or integration problems when depositing a copper diffusion barrier.

[0040] The composition for depositing the dielectric film described herein comprises: about 5 to about 60 weight % of a structure forming precursor comprising an alkyl-alkoxysilacyclic compound having Formula I; and about 40 to about 95 weight % of a pore former precursor depending on the nature of the pore former precursor.

[0041] In certain embodiments of the methods and compositions contained herein, the structure forming precursor further comprises a hardening additive having the formula R 1 n Si(OR 2 ) 4-n wherein R 1 and R 2 are as defined above and n = 0, 1, 2, 3, which increases mechanical strength. Examples of hardening additives include tetraalkoxysilanes, wherein R 1 n Si(OR 2 ) 4-nn = 0, such as tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS). Another example of a hardening additive includes a dialkyldialkoxysilane, such as dimethyldimethoxysilane, dimethyldiethoxysilane. In embodiments where a hardening additive is used, the composition of the structure-forming portion comprises about 30 to about 95 weight percent of a structure-forming precursor comprising an alkyl-alkoxysilacyclic compound having Formula I; about 5 to about 70 weight percent of a hardening additive; and about 40 to 95 weight percent of the total precursor flow of a pore former precursor.

[0042] As previously mentioned, the gaseous reagent also includes one or more pore former precursors introduced into the reaction chamber along with at least one structure-forming precursor comprising an alkoxysilacyclic or acyloxysilacyclic compound, such as 1,1-dimethoxy-1-silacyclopentane. The following are non-limiting examples of materials suitable for use as pore formers according to the present application: 1) a cyclic hydrocarbon of the general formula C n H 2n where n = 4-14, where the number of carbons in the ring structure is between 4 and 10, and where there can be (i.e., optionally) a number of simple or branched hydrocarbons substituted onto the ring structure.

[0043] Examples include cyclohexane, 1,2,4-trimethylcyclohexane, 1-methyl-4-(1- methylethyl)cyclohexane, cyclooctane, methylcyclooctane, methylcyclohexane, and the like.

[0044] 2) a linear or branched, saturated, mono-unsaturated or poly-unsaturated hydrocarbon of the general formula C n H (2n+2)-2y where n = 2-20, and where y = 0-n.

[0045] Examples include ethylene, propylene, acetylene, neohexane, 1,3-butadiene, 2-methyl- 1,3-butadiene, 2,3-dimethyl-2,3-butadiene, substituted dienes, and the like.

[0046] 3) a mono-unsaturated or poly-unsaturated cyclic hydrocarbon of the general formula C n H 2n-2x where x is the number of unsaturation sites in the molecule, n = 4-14, where the number of carbons in the ring structure is between 4 and 10, and where there can be a number of simple or branched hydrocarbons substituted onto the ring structure. The unsaturation can be located on the interior of the endocyclic ring or on one of the hydrocarbon substituents of the ring structure.

[0047] Examples include p-cymene, cyclooctene, 1,5-cyclooctadiene, dimethyl-cyclooctadiene, cyclohexene, vinylcyclohexane, dimethylcyclohexene, a-terpinene, pinene, limonene, vinylcyclohexene, and the like.

[0048] 4) a linear or branched, saturated, mono-unsaturated or poly-unsaturated hydrocarbon of the general formula C n H2n-2 bicyclic hydrocarbons of the formula C

[0049] Examples include norbornane, spiro nonane, decalin, and the like.

[0050] 5) tricyclic hydrocarbons of the formula C n H 2n-(2+2x) polyunsaturated bicyclic hydrocarbons of the formula C

[0051] Examples include camphene, norbornene, norbornadiene, 5- ethylidene-2-norbornene, and the like.

[0052] 6) tricyclic hydrocarbons of the formula C n H 2n-4 tricyclic hydrocarbons of the formula C

[0053] Examples include adamantane.

[0054] While the phrase "gaseous reagent" is sometimes used herein to describe a reagent, this phrase is intended to encompass reagents that are delivered as a gas directly to the reactor, as a vaporized liquid, a sublimed solid, and / or transported into the reactor by an inert carrier gas.

[0055] Further, the reagents can be carried into the reactor individually from different sources or as a mixture. The reagents can be delivered to the reactor system in a variety of ways, preferably using pressurizable stainless steel containers fitted with appropriate valves and fittings to allow liquid delivery to the process reactor.

[0056] In addition to the structure-forming and pore-forming materials, additional materials can optionally be introduced into the reaction chamber prior to, during, and / or after the deposition reaction. Such materials include, for example, inert gases (e.g., He, Ar, N2, Kr, Xe), and the like, which can serve as a carrier gas for lower volatility precursors and / or which can promote solidification of the material so deposited and provide a more stable final film, and reactive species, such as oxygen-containing species, e.g., O2, O3, and N2O, gaseous or liquid organic species, NH3, H2, CO2, or CO. In one particular embodiment, the reaction mixture introduced into the reaction chamber comprises at least one oxidizing agent selected from the group consisting of O2, N2O, NO, NO2, CO2, water, H2O2, ozone, and combinations thereof. In an alternative embodiment, the reaction mixture does not comprise an oxidizing agent.

[0057] Energy is applied to the gaseous reagents to induce a gas reaction and form a film on the substrate. Such energy can be provided by, for example, plasma, pulsed plasma, spiral wave plasma, high density plasma, inductively coupled plasma, remote plasma, hot filament, and thermal (i.e., non-filament) methods. A secondary RF source can be used to vary the plasma characteristics at the substrate surface. Preferably, the film is formed by plasma enhanced chemical vapor deposition ("PECVD").

[0058] The flow rate of each gaseous reagent is preferably in the range of 10-5000 seem per individual 200 mm wafer, more preferably 30-1000 seem. The individual rates are selected so as to provide the desired amount of structure-forming precursor and pore former in the film. The actual flow rates required can depend on wafer size and chamber configuration, and are in no way limited to 200 mm wafers or single wafer chambers.

[0059] In some embodiments, the film is deposited at a deposition rate of about 50 nanometers (nm) per minute.

[0060] The pressure in the reaction chamber during deposition is in the range of about 0.01 to about 600 Torr, or about 1 to 15 Torr.

[0061] The film is preferably deposited to a thickness of 0.002 to 10 microns, although the thickness can be varied as desired. The blanket film deposited on a non-patterned surface has excellent uniformity, with a thickness variation of less than 2% of one standard deviation across the substrate (with reasonable edge exclusion), where, for example, the outermost 5 mm edges of the substrate are not included in the statistical calculation of uniformity.

[0062] The porosity of the film can be increased with a corresponding decrease in bulk density to result in a further decrease in the dielectric constant of the material and extend the applicability of the material to future generations (e.g., k < 2.0).

[0063] As previously described, at least a portion of the pore former precursor contained in the film as deposited is removed in a subsequent removal step to substantially all of the pore former precursor. The removal of the pore former precursor is by one or more of the following processes: thermal treatment, UV treatment, e-beam treatment, gamma radiation treatment, and combinations thereof. In one particular embodiment, the pore former removal step is performed by a UV treatment step, a thermal treatment step, or a combination thereof. In the latter embodiment, the UV treatment step occurs during at least a portion of the thermal treatment.

[0064] If there is no statistically significant measured difference in atomic composition between the annealed porous OSG and a similar OSG without the addition of pore forming agent, it is assumed that at least a portion of substantially all of the pore forming agent contained in the as-deposited film is removed. As used herein, the term "substantially free" when referring to the removal of pore forming agent precursors in the as-deposited film means about 2% or less, or about 1% or less, or about 50 ppm or less, or about 10 ppm or less, or about 5 ppm or less of pore forming agent as measured by XPS or other means. Both the inherent measurement error and process variability of the analytical methods used for composition (such as X-ray photoelectron spectroscopy (XPS), Rutherford backscattering / hydrogen forward scattering (RBS / HFS)) contribute to the range of data. For XPS, the inherent measurement error is approximately + / - 2 atomic percent, while for RBS / HFS, this is expected to be larger, ranging from + / - 2 to 5 atomic percent depending on the material. Process variability contributes an additional + / - 2 atomic percent to the final range of data.

[0065] Preferred embodiments of the present application provide thin film materials having low dielectric constants and improved mechanical properties, thermal stability, and chemical resistance (to oxygen, aqueous oxidizing environments, etc.) relative to other porous low-k dielectric films deposited using other structure-forming precursors known in the art. The structure-forming precursors described herein include alkyl-alkoxy and acyl silacyclic, alkoxysilacyclic, or acyloxysilacyclic compounds having the formula I provide more carbon incorporation into the film (preferably primarily as organic carbon-CH x in the form of H2C=CH2, where x is 1 to 3), thereby using the particular precursor or network-forming chemistry to deposit the film. In certain embodiments, a majority of the hydrogen in the film is bonded to carbon.

[0066] Low-k dielectric films deposited according to the compositions and methods described herein include: (a) about 10 to about 35 atomic percent, more preferably about 20 to about 30 atomic percent, of silicon; (b) about 10 to about 65 atomic percent, more preferably about 20 to about 45 atomic percent, of oxygen; (c) about 10 to about 50 atomic percent, more preferably about 15 to about 40 atomic percent, of hydrogen; (d) about 5 to about 40 atomic percent carbon, more preferably about 10 to about 45 atomic percent carbon. The films can also contain about 0.1 to about 15 atomic percent, more preferably about 0.5 to about 7.0 atomic percent, of fluorine to improve one or more material properties. Smaller portions of other elements can also be present in certain films of the present application. The OSG materials are considered low-k materials because their dielectric constants are less than that of standard materials commonly used in the industry - silicon glass. The materials of the present application can have pore forming substances or pore forming agents added to the deposition procedure, introducing the pore forming agents into the as-deposited (i.e., initial) OSG film, and removing substantially all of the pore forming agents from the initial film while substantially retaining the terminal Si-CH3 groups or bridging- (CH2) x- to provide a product film. The product film is a porous OSG and has a dielectric constant that is reduced from the starting film and from a similar film deposited without a pore former. It is important to distinguish the film of the present invention, which is a porous OSG, from a porous inorganic Si02 that lacks the hydrophobicity provided by the organic groups in the OSG.

[0067] For example, silica prepared from CVD-TEOS has an intrinsic free volume pore size of about 0.6 nm equivalent spherical diameter as determined by positron annihilation lifetime spectroscopy (PALS) analysis. The pore size of the film of the present invention, as determined by small angle neutron scattering (SANS) or PALS, is preferably less than 5 nm equivalent spherical diameter, more preferably less than 2.5 nm equivalent spherical diameter.

[0068] The total porosity of the film can range from 5% to 75%, depending on the process conditions and the desired final film properties. The film of the present invention preferably has a density of less than 2.0 g / ml, or, less than 1.5 g / ml or less than 1.25 g / ml. Preferably, the film of the present invention has a density that is at least 10% lower, more preferably at least 20% lower, than a similar OSG film prepared without a pore former.

[0069] The porosity of the film need not be uniform throughout the film. In certain embodiments, there is a porosity gradient and / or layers of different porosity. Such films can be provided, for example, by adjusting the ratio of pore former to precursor during deposition.

[0070] The film of the present invention has a lower dielectric constant than common OSG materials, which have a dielectric constant ranging from 2.8 to 3.8. Preferably, the film of the present invention has a dielectric constant that is at least 0.3 lower, more preferably at least 0.5 lower, than the dielectric constant of a similar OSG film prepared without a pore former. Preferably, the Fourier transform infrared spectrum (FTIR) of the porous film of the present invention is substantially the same as the reference FTIR of a reference film prepared by a process that is substantially the same as the process except for the lack of any pore former.

[0071] The film of the present invention can also contain fluorine in the form of inorganic fluorine (e.g., Si-F). The fluorine, when present, is preferably included in an amount ranging from 0.5 to 7 atomic %.

[0072] The film of the present invention is thermally stable, with good chemical resistance. In particular, preferred films have an average weight loss of less than 1.0 wt% / hr at 425°C isothermally under nitrogen after annealing. Also, the films preferably have an average weight loss of less than 1.0 wt% / hr at 425°C isothermally under air.

[0073] The films are suitable for a variety of uses. The films are particularly suitable for deposition on semiconductor substrates and are particularly suitable for use as, for example, insulating layers, interlayer dielectric layers, and / or intermetal dielectric layers. The films can form conformal coatings. The mechanical properties exhibited by these films make them particularly suitable for use in aluminum subtractive technology and copper damascene or dual damascene technology.

[0074] The films are compatible with chemical mechanical planarization (CMP) and anisotropic etching and can adhere to a variety of materials, such as silicon, SiO2, Si3N4, OSG, FSG, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, boron nitride, antireflective coatings, photoresists, organic polymers, porous organic and inorganic materials, metals (such as copper and aluminum), and diffusion barrier layers (such as, but not limited to, TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, WN, or W(C)N). The films are preferably capable of adhering sufficiently to at least one of the above-mentioned materials to pass a conventional tensile test, such as the ASTM D3359-95a tape tensile test. A sample is considered to have passed the test if there is no visible removal of the film.

[0075] Thus, in certain embodiments, the film is an insulating layer, an interlayer dielectric layer, an intermetal dielectric layer, a capping layer, a chemical mechanical planarization (CMP) or etch stop layer, a barrier layer, or an adhesion layer in an integrated circuit.

[0076] Although the films described herein are uniform, deposited dielectric films, the films as used in a full integration structure can actually be composed of multiple sandwiched layers, for example, a thin layer with a bottom or top that contains little or no deposited pore former, or a layer can be deposited under conditions where there is a lower pore former precursor flux, or, for example, a layer can be deposited at a higher plasma power so that not all of the pore former precursor can be removed by UV treatment. These sandwiched layers can be used to enhance secondary integration properties, such as adhesion, etch selectivity, or electromigration performance.

[0077] Although the present invention is particularly suitable for providing films, and the products of the present invention are primarily described herein as films, the present invention is not so limited. The products of the present invention can be provided in any form that can be deposited by CVD, such as coatings, multilayer assemblies, and other types of objects that are not necessarily planar or thin, and many objects that are not necessarily used in integrated circuits. Preferably, the substrate is a semiconductor.

[0078] In addition to the OSG products of the present invention, the present disclosure includes methods by which the products are made, methods of using the products, and compounds and compositions useful in making the products. For example, methods for making integrated circuits on semiconductor devices are disclosed in U.S. Patent 6,583,049, which is incorporated herein by reference.

[0079] The pore former in the deposited film can or can not be in the same form as the pore former introduced into the reaction chamber. In addition, the pore former removal process can release the pore former or fragments thereof from the film. In essence, the pore former reagent (or pore former surrogate attached to the precursor), the pore former in the initial film, and the removed pore former can or can not be the same substance, although it is preferred that they all originate from the pore former reagent (or pore former surrogate). Regardless of whether the pore former is constant throughout the inventive process, the term "pore former" as used herein is intended to encompass the pore forming reagent (or pore forming surrogate) and its derivatives, regardless of the form in which it exists throughout the inventive process.

[0080] The compositions of the present invention can further include, for example, at least one pressurizable container (preferably stainless steel) equipped with appropriate valves and fittings to allow delivery of the pore former and the alkoxy- or acyloxy-silacyclic precursors to the process reactor. The contents of the container can be pre-mixed. Alternatively, the pore former and the precursors can be maintained in separate containers, or in a single container with a separation device that maintains the pore former and the precursors separate during storage. Such containers can also have means for mixing the pore former and the precursors when needed.

[0081] The pore former is removed from the initial (or as deposited) film by a curing step, which can include thermal annealing, chemical treatment, in-situ or remote plasma treatment, photo-curing (e.g., UV), and / or microwave treatment. Other in-situ or post-deposition treatments can be used to enhance material properties, such as hardness, stability (against shrinkage, air exposure, etching, wet etching, etc.), integrity, uniformity, and adhesion. Such treatments can be applied to the film before, during, and / or after pore former removal, using the same or different means as used for pore former removal. Thus, the term "post-treatment" as used herein means the use of energy (e.g., heat, plasma, photons, electrons, microwaves, etc.) or chemicals to treat the film to remove the pore former, and optionally, to enhance material properties.

[0082] The conditions under which post-treatment is performed can vary greatly. For example, post-treatment can be performed under high pressure or vacuum.

[0083] UV annealing is a preferred method performed under the following conditions.

[0084] The environment can be inert (e.g. nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g. oxygen, air, dilute oxygen environments, oxygen enriched environments, ozone, nitrous oxide, etc.) or reductive (dilute or concentrated hydrogen, hydrocarbons (saturated, unsaturated, straight or branched, aromatic), etc.). The pressure is preferably from about 1 Torr to about 1000 Torr, more preferably atmospheric pressure. However, a vacuum environment is also possible for thermal annealing as well as any other post processing means. The temperature is preferably from 200-500°C, with a temperature ramp rate of 0.1-100°C / min. The total UV annealing time is preferably from 0.01 minutes to 12 hours.

[0085] The OSG film is chemically treated under the following conditions.

[0086] Fluorination (HF, SIF4, NF3, F2, COF2, CO2F2, etc.), oxidation (H2O2, O3, etc.), chemical drying, methylation or other chemical treatments that enhance the properties of the final material are used. The chemicals used in such treatments can be in solid, liquid, gas and / or supercritical fluid states.

[0087] Supercritical fluid post processing is performed to selectively remove the pore forming agent from the organosilicate film under the following conditions.

[0088] The fluid can be carbon dioxide, water, nitrous oxide, ethylene, SF6and / or other types of chemicals. Other chemicals can be added to the supercritical fluid to enhance the process. The chemicals can be inert (e.g. nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g. oxygen, ozone, nitrous oxide, etc.) or reductive (e.g. dilute or concentrated hydrocarbons, hydrogen, hydrogen containing plasma, etc.). The temperature is preferably from ambient temperature to 500°C. The chemicals can also include larger chemical species such as surfactants. The total exposure time is preferably from 0.01 minutes to 12 hours.

[0089] Plasma processing is performed to selectively remove unstable groups and to possibly chemically modify the OSG film under the following conditions.

[0090] The environment can be inert (e.g. nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g. oxygen, air, dilute oxygen environments, oxygen enriched environments, ozone, nitrous oxide, etc.) or reductive (e.g. dilute or concentrated hydrogen, hydrocarbons (saturated, unsaturated, straight or branched, aromatic), etc.). The plasma power is preferably from 0-5000 W. The temperature is preferably from ambient temperature to 500°C. The pressure is preferably from 10 mTorr to atmospheric pressure. The total curing time is preferably from 0.01 minutes to 12 hours.

[0091] UV curing is performed under the following conditions to selectively remove the pore former from the organosilicate film.

[0092] The environment can be inert (e.g., nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g., oxygen, air, dilute oxygen environment, oxygen-rich environment, ozone, nitrous oxide, etc.), or reductive (e.g., dilute or concentrated hydrocarbons, hydrogen, etc.). The temperature is preferably ambient to 500°C. The power is preferably 0 to 5000 W. The wavelength is preferably infrared, visible, UV, or deep UV (wavelength < 200 nm). The total UV curing time is preferably 0.01 minutes to 12 hours.

[0093] Microwave post-treatment is performed under the following conditions to selectively remove the pore former from the organosilicate film.

[0094] The environment can be inert (e.g., nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g., oxygen, air, dilute oxygen environment, oxygen-rich environment, ozone, nitrous oxide, etc.), or reductive (e.g., dilute or concentrated hydrocarbons, hydrogen, etc.). The temperature is preferably ambient to 500°C. The power and wavelength vary and are tunable depending on the specific bond. The total curing time is preferably 0.01 minutes to 12 hours.

[0095] Electron beam post-treatment is performed under the following conditions to selectively remove the pore former or specific chemical species from the organosilicate film and / or to improve film properties.

[0096] The environment can be vacuum, inert (e.g., nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidative (e.g., oxygen, air, dilute oxygen environment, oxygen-rich environment, ozone, nitrous oxide, etc.), or reductive (e.g., dilute or concentrated hydrocarbons, hydrogen, etc.). The temperature is preferably ambient to 500°C. The electron density and energy can vary and are tunable depending on the specific bond. The total curing time is preferably 0.001 minutes to 12 hours and can be continuous or pulsed. Additional guidance on the general use of electron beams is available from publications such as: S. Chattopadhyay et al., Journal of Materials Science, 36 (2001) 4323-4330; G. Kloster et al., Proceedings of IITC, June 3-5, 2002, SF, CA; and U.S. Patent Nos. 6,207,555 Bl, 6,204,201 Bl, and 6,132,814 Al. The use of electron beam treatment can provide pore former removal and enhanced film mechanical properties through the bond formation process in the matrix.

[0097] Accordingly, the present application provides at least the following: 1. A method for preparing a dielectric film represented by the formula: Si v O w C x H y F z wherein v + w + x + y + z = 100%, v is 10 to 35 atomic %, w is 10 to 65 atomic %, x is 5 to 40 atomic %, y is 10 to 50 atomic %, and z is 0 to 15 atomic %, the method comprising: providing a substrate within a reaction chamber; introducing a gaseous reagent into the reaction chamber, the gaseous reagent comprising at least one structure-forming precursor comprising an alkoxy- or acyloxy-silaheterocyclic compound and a pore former, wherein the alkoxy- or acyloxy-silaheterocyclic compound has a structure represented by Formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R 3 , wherein each R 1-3 is independently selected from the group consisting of linear or branched C1 to C 10 alkyl, linear or branched C2 to C 10 alkenyl, linear or branched C2 to C 10 alkynyl, C3 to C 10 cycloalkyl, C3 to C 10 heterocycloalkyl, C5 to C 10 aryl, and C3 to C 10 heteroaryl; and R 4 is a C3 to C 10 alkyldiyl forming a four-, five-, or six-membered saturated cyclic ring with the Si atom, optionally, at least one oxygen source, and optionally, at least one pore former; applying energy to the gaseous reagent in the reaction chamber to induce a reaction of the gaseous reagent to deposit an initial film on the substrate, wherein the initial film comprises the pore former; and removing at least a portion of the pore former from the initial film to provide a porous dielectric film comprising pores and having a dielectric constant of about 2.6 or less.

[0098] 2. The method of item 1, wherein the structure-forming precursor further comprises a hardening additive.

[0099] 3. The method according to item 1, wherein the alkoxy-silacyclic or acyloxy-silacyclic compound comprises at least one selected from the group consisting of 1,1-dimethoxy-1- silacyclopentane, 1,1-diethoxy-1-silacyclopentane, 1,1-di-n-propoxy-1-silacyclopentane, 1,1-di-iso-propoxy-1-silacyclopentane, 1,1-dimethoxy-1-silacyclobutane, 1,1-diethoxy-1- silacyclobutane, 1,1-di-n-propoxy-1-silacyclobutane, 1,1-di-iso-propoxy-1-silacyclobutane, 1,1-dimethoxy-1-silacyclohexane, 1,1-di-iso-propoxy-1-silacyclohexane, 1,1-di-n- propoxy-1-silacyclohexane, 1-methoxy-1-acetoxy-1-silacyclopentane, 1,1-diacetoxy-1- silacyclopentane, 1-methoxy-1-acetoxy-1-silacyclobutane, 1,1-diacetoxy-1-silacyclobutane, 1-methoxy-1-acetoxy-1-silacyclohexane, 1,1-diacetoxy-1-silacyclohexane, 1-ethoxy-1- acetoxy-1-silacyclopentane, 1-ethoxy-1-acetoxy-1-silacyclobutane, and combinations thereof.

[0100] 4. The method according to item 1, wherein the pore former is cyclooctane.

[0101] 5. The method according to item 2, wherein the hardening additive comprises tetraethoxysilane.

[0102] 6. The method according to item 2, wherein the hardening additive comprises tetramethoxysilane.

[0103] 7. The method according to item 1, which is a plasma-enhanced chemical vapor deposition method.

[0104] 8. The method according to item 1, wherein the reaction mixture comprises at least one oxidizing agent selected from the group consisting of O2, N2O, NO, NO2, CO2, water, H2O2, ozone, and combinations thereof.

[0105] 9. The method according to item 1, wherein the reaction mixture does not comprise an oxidizing agent.

[0106] 10. The method according to item 1, wherein the reaction chamber in the applying step comprises at least one gas selected from the group consisting of He, Ar, N2, Kr, Xe, NH3, H2, CO2, and CO.

[0107] 11. The method according to item 1, wherein the removing step comprises at least one treatment selected from the group consisting of heat treatment, ultraviolet (UV) treatment, electron beam treatment, gamma radiation treatment, and combinations thereof.

[0108] 12. The method of item 11, wherein the UV treatment occurs during at least a portion of the heat treatment.

[0109] 13. The method of item 1, wherein the pore former precursor is selected from the group consisting of: a) a substituted or unsubstituted cyclic hydrocarbon having the formula C n H 2n wherein n = 4 to 14, b) a substituted or unsubstituted hydrocarbon of the general formula C n H (2n+2)-2y wherein n = 2 to 20 and y = 0 to n, wherein n = 4 to 14, c) a substituted or unsubstituted mono- or poly-unsaturated cyclic hydrocarbon having the formula C n H 2n-2x wherein x is the number of unsaturation sites in the molecule and n = 4 to 14, d) a substituted or unsubstituted bicyclic hydrocarbon having the formula C n H 2n-2 wherein n = 4 to 14, e) a substituted or unsubstituted poly-unsaturated bicyclic hydrocarbon having the formula C n H 2n-(2+2x) wherein x is the number of unsaturation sites in the molecule and n = 4 to 14, wherein the number of carbons in the bicyclic structure is between 4 and 12, and f) a substituted or unsubstituted tricyclic hydrocarbon having the formula C n H 2n-4 wherein n = 4 to 14, wherein the number of carbons in the tricyclic structure is between 4 and 12.

[0110] 14. The method of item 1, wherein the pore former precursor in item 13 comprises at least one selected from the group consisting of cyclohexane, 1,2,4-trimethylcyclohexane, 1-methyl-4-(1-methylethyl)cyclohexane, cyclooctane, methylcyclooctane, ethylene, propylene, acetylene, neohexane, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-2,3-butadiene, substituted dienes, p-cymene, cyclooctene, 1,5-cyclooctadiene, cyclohexene, vinylcyclohexane, dimethylcyclohexene, alpha-terpinene, pinene, limonene, vinylcyclohexene, norbornane, spiro nonane, camphene, norbornene, norbornadiene, 5-ethylidene-2-norbornene, decahydronaphthalene, adamantane, and combinations thereof.

[0111] 15. A composition for chemical vapor deposition of a dielectric film, wherein the composition comprises an alkoxy silacyclic or acyloxy silacyclic compound having the following formula I: (I), wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R 3 , wherein each R 1-3 is independently selected from the group consisting of linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl, and C3to C 10 heteroaryl; and R 4 is C3to C 10 alkyl diradical forming a four-, five-, or six-membered saturated cyclic ring with the Si atom, and wherein the compound is substantially free of one or more impurities selected from the group consisting of halides, water, and combinations thereof.

[0112] 16. The composition of item 15, wherein the alkoxy silacyclic or acyloxy silacyclic compound comprises at least one selected from the group consisting of 1,1-dimethoxy-1- silacyclopentane, 1,1-diethoxy-1-silacyclopentane, 1,1-di-n-propoxy-1-silacyclopentane, 1,1-di-iso-propoxy-1-silacyclopentane, 1,1-dimethoxy-1-silacyclobutane, 1,1-diethoxy-1- silacyclobutane, 1,1-di-n-propoxy-1-silacyclobutane, 1,1-di-iso-propoxy-1-silacyclobutane, 1,1-dimethoxy-1-silacyclohexane, 1,1-di-iso-propoxy-1-silacyclohexane, 1,1-di-n- propoxy-1-silacyclohexane, 1-methoxy-1-acetoxy-1-silacyclopentane, 1,1-diacetoxy-1- silacyclopentane, 1-methoxy-1-acetoxy-1-silacyclobutane, 1,1-diacetoxy-1-silacyclobutane, 1-methoxy-1-acetoxy-1-silacyclohexane, 1,1-diacetoxy-1-silacyclohexane, 1-ethoxy-1- acetoxy-1-silacyclopentane, 1-ethoxy-1-acetoxy-1-silacyclobutane, and combinations thereof.

[0113] 17. The composition of item 15, wherein the halide comprises chloride ions.

[0114] 18. Use of an alkoxy silacyclic or acyloxy silacyclic compound having the following formula I for depositing a low-k dielectric film by vapor deposition: (I) wherein X and Y are independently selected from the group consisting of OR 1 , OR 2 , and OC(O)R3 wherein R 1-3 each independently is selected from linear or branched C1to C 10 alkyl, linear or branched C2to C 10 alkenyl, linear or branched C2to C 10 alkynyl, C3to C 10 cycloalkyl, C3to C 10 heterocycloalkyl, C5to C 10 aryl and C3to C 10 heteroaryl; and R 4 is C3to C 10 alkyl diradical forming a four-, five- or six-membered saturated cyclic ring with the Si atom.

[0115] 19. The use according to item 18, wherein the compound is substantially free of one or more impurities selected from halides, water, and combinations thereof.

[0116] 20. The use according to item 18, wherein the alkoxy silicon heterocyclic or acyloxy silicon heterocyclic compound comprises at least one selected from the group consisting of 1,1-dimethoxy-1-silacyclopentane, 1,1-diethoxy-1-silacyclopentane, 1,1-di-n- propoxy-1-silacyclopentane, 1,1-di-i-propoxy-1-silacyclopentane, 1,1-dimethoxy-1- silacyclobutane, 1,1-diethoxy-1-silacyclobutane, 1,1-di-n-propoxy-1-silacyclobutane, 1,1-di-i-propoxy-1-silacyclobutane, 1,1-dimethoxy-1-silacyclohexane, 1,1-di-i-propoxy-1- silacyclohexane, 1,1-di-n-propoxy-1-silacyclohexane, 1-methoxy-1-acetoxy-1- silacyclopentane, 1,1-diacyloxy-1-silacyclopentane, 1-methoxy-1-acetoxy-1- silacyclobutane, 1,1-diacyloxy-1-silacyclobutane, 1-methoxy-1-acetoxy-1- silacyclohexane, 1,1-diacyloxy-1-silacyclohexane, 1-ethoxy-1-acetoxy-1- silacyclopentane, 1-ethoxy-1-acetoxy-1-silacyclobutane, and combinations thereof.

[0117] 21. The use according to item 19, wherein the halide comprises chloride ions.

[0118] 22. The use according to item 21, wherein the chloride ions are less than 50 ppm.

[0119] 23. The use according to item 21, wherein the chloride ions are less than 10 ppm.

[0120] 24. The use according to item 21, wherein the chloride ions are less than 5 ppm.

[0121] 25. The use of item 18, wherein the vapor deposition is chemical vapor deposition.

[0122] 26. The use of item 25, wherein the chemical vapor deposition is plasma enhanced chemical vapor deposition.

[0123] 27. The composition of item 15, further comprising at least one member selected from the group consisting of a carrier gas and an oxidizing agent.

[0124] 28. The composition of item 27, wherein the member comprises at least one member selected from the group consisting of helium and oxygen.

[0125] 29. The composition of item 15, further comprising at least one stiffening additive.

[0126] 30. The composition of item 29, wherein the stiffening additive comprises at least one tetraalkoxysilane.

[0127] 31. A film formed by the method, wherein the structure of the film comprises at least one of -CH2- methylene bridges and -CH2CH2- ethylene bridges.

[0128] The application will be explained in greater detail with reference to the following examples, but it should be understood that the application is not to be construed as being limited thereto.

[0129] Examples Exemplary films or 200 mm wafer processing were formed from a variety of different chemical precursors and process conditions using an Applied Materials Precision-5000 system in a 200 mm DxZ reaction chamber or vacuum chamber (which was outfitted with an Advance Energy 200 RF generator) by a plasma enhanced CVD (PECVD) method. The PECVD method generally included the following basic steps: initial establishment and stabilization of gas flow, film deposition onto a silicon wafer substrate, and purging / evacuation of the chamber prior to substrate removal. After deposition, the films were subjected to UV annealing. UV annealing was performed using a Fusion UV system with broadband UV bulbs, with the wafer held in a helium stream at one or more pressures below 10 torr and at one or more temperatures below 400°C. Experiments were performed on p-type Si wafers (resistivity range = 8-12 Ohm-cm).

[0130] Thickness and refractive index were measured on a SCI FilmTek 2000 reflectometer. Dielectric constant was determined on moderately resistive p-type wafers (range 8-12 ohm-cm) using the Hg-probe technique. FTIR spectra were measured using a Nicholet Nexxus 470 spectrometer. In Comparative Example 1 and Example 1, mechanical properties were determined using an MTS Nano Indenter. Composition data were obtained with X-ray photoelectron spectroscopy (XPS) on a Physical Electronics 5000 LS and are provided in atomic weight percent. The atomic weight percent values reported in the tables do not include hydrogen.

[0131] Comparative Example 1 Deposition of porous OSG films from diethoxymethylsilane (DEMS) and cyclooctane A composite layer of structure-forming DEMS and pore-forming precursor cyclooctane was deposited for 200 mm processing using the following process conditions. The precursors were delivered to the reaction chamber by direct liquid injection (DLI) at the following flow rates: 960 milligrams per minute (mg / min) cyclooctane and 240 mg / min (using 200 standard cubic centimeters (seem) CO2carrier gas flow), 10 seem O2, 350 millimeter (mm) showerhead / wafer spacing, 275 °C wafer chuck temperature, 8 Torr chamber pressure, to which 600 W plasma was applied. The resulting film was then UV annealed to remove the cyclooctane pore former and mechanically strengthen the film. Various properties of the film (e.g., dielectric constant (k), modulus (GPa), and carbon atomic weight percent (%C)) were obtained as described above.

[0132] Example 1 Deposition of porous OSG films from 1,1-diethoxy-1-silacyclopentane (DESCP) with cyclooctane as a sacrificial pore former precursor, followed by UV curing: A composite layer was deposited using DESCP as the structure forming precursor and cyclooctane as the pore former precursor. The deposition conditions for depositing the composite film on a 200 mm wafer were as follows: the precursors were delivered to the reaction chamber by direct liquid injection (DLI) at the following flow rates: 363 mg / min of DESCP, 737 mg / min of cyclooctane, 200 seem of helium carrier gas flow, 10 seem of O2, 350 mils showerhead / wafer spacing, 250 °C wafer chuck temperature, 8 Torr chamber pressure, to which 600 W plasma was applied for 100 seconds. The resulting film so deposited was 757 nm thick with a refractive index (RI) of 1.47. After deposition, the composite film was exposed to a UV anneal step for a period of 12 minutes. After UV anneal, the film shrunk by 24% to 576 nm thick with a refractive index of 1.38. The dielectric constant of the film was 2.50, the modulus was 10.4 GPa, and the hardness was 1.4 GPa. The elemental composition by XPS analysis was 21.4% C, 46.5% O, 32.1% Si.

[0133] Example 2 Deposition of porous OSG film from 1,1-dimethoxy-1-silacyclopentane (DMSCP) and cyclooctane (predictive) A composite layer of structure forming DMSCP and pore former precursor cyclooctane was deposited for 200 mm processing using the following process conditions. The precursors were delivered to the reaction chamber by direct liquid injection (DLI) at a flow rate of 960 mg / min of cyclooctane, and 240 mg / min of DMSCP using a 200 seem CO2carrier gas flow to the reaction chamber, 20 seem O2, 350 mils showerhead / wafer spacing, 250 °C wafer chuck temperature, 8 Torr chamber pressure, to which 600 W plasma was applied. The resulting film was then subjected to a UV anneal to remove the pore former and mechanically strengthen the film. Various properties of the film (e.g., dielectric constant (k), modulus (GPa), and carbon atomic weight percent (%C)) were obtained as described above.

[0134] Comparative Example 2 Deposition of OSG film from 1-methyl-1-ethoxy-1-silacyclopentane (MESCP) with cyclooctane as a sacrificial pore former precursor followed by UV cure: A composite layer was deposited using MESC as the structure forming precursor and cyclooctane as the pore former precursor precursor. The deposition conditions for depositing this composite film on a 200 mm wafer were as follows: the precursors were delivered to the reaction chamber by direct liquid injection (DLI) at the following flow rates: 280 milligrams / minute (mg / min) of DESCP, 800 mg / min of cyclooctane, 200 standard cubic centimeters (seem) of helium carrier gas flow, 25 seem of 02, 350 mils showerhead / wafer spacing, 300 °C wafer chuck temperature, 8 torr chamber pressure, to which 600 W plasma was applied for 120 seconds. The resulting film so deposited was 567 nm thick with a refractive index (RI) of 1.45. After deposition, the composite film was exposed to a UV anneal step for a period of 12 minutes. After UV anneal, the film shrank by 17% to 467 nm thick with a refractive index of 1.39. The dielectric constant of this film was 2.54, the modulus was 8.6 GPa, and the hardness was 1.3 GPa. The elemental composition by XPS analysis was 23.0% C, 45.6% O, 31.4% Si.

[0135] Comparative Example 3 OSG film was deposited from diethoxymethylsilane (DEMS) with cyclooctane as a sacrificial pore former precursor, followed by UV curing: A composite layer was deposited using DESCP as the structure forming precursor and cyclooctane as the pore former precursor precursor. The deposition conditions for depositing this composite film on a 200 mm wafer were as follows: the precursors were delivered to the reaction chamber by direct liquid injection (DLI) at the following flow rates: 220 milligrams / minute (mg / min) of DESCP, 880 mg / min of cyclooctane, 200 standard cubic centimeters (seem) of helium carrier gas flow, 25 seem of 02, 350 mils showerhead / wafer spacing, 250 °C wafer chuck temperature, 8 torr chamber pressure, to which 600 W plasma was applied for 80 seconds. The resulting film so deposited was 411 nm thick with a refractive index (RI) of 1.44. After deposition, the composite film was exposed to a UV anneal step for a period of 12 minutes. After UV anneal, the film shrank by 19% to 334 nm thick with a refractive index of 1.36. The dielectric constant of this film was 2.50, the modulus was 8.5 GPa, and the hardness was 1.0 GPa. The elemental composition by XPS analysis was 13.2% C, 54.0% O, 32.8% Si.

[0136] Example 4 Synthesis of 1,1-diethoxy-1-silacyclopentane To 130.0 g (838 mmol) 1,1-dichloro-1-silacyclopentane in 900 mL hexanes in a three neck 2000 mL round bottom flask equipped with a magnetic stir bar and reflux condenser, 93.0 g (2012 mmol) ethanol was added via addition funnel while heating the contents under reflux. Once the addition was complete, the reaction mixture was refluxed for an additional 30 minutes and then cooled to room temperature while purging with nitrogen to remove HCl. GC of the reaction mixture showed approximately 75% conversion to the desired 1,1-diethoxy-1-silacyclopentane. The remainder was monosubstituted 1-chloro-1-ethoxy-1-silacyclopentane. To the reaction mixture was added an additional 19.0 g (419 mmol) ethanol and 42.0 g (419 mmol) triethylamine to complete the conversion of the monosubstituted material to product. The resulting white slurry was stirred at room temperature overnight. The slurry was then filtered. The solvent was removed by distillation at atmospheric pressure. The product was vacuum distilled at 5 torr, boiling point 46 °C, amount 143 g. Yield 90%.

[0137] Example 5 Synthesis of 1,1-dimethoxy-1-silacyclopentane To 100.0 g (645 mmol) 1,1-dichloro-1-silacyclopentane in 1800 mL of a hexanes / THF 1:1 mixture in a three neck 3000 mL round bottom flask equipped with a magnetic stir bar was added 260.0 g (2579 mmol) triethylamine followed by 62.0 g (1934 mmol) methanol at 0 °C. The resulting white slurry was warmed to room temperature and stirred for 16 hours before being filtered on a medium porosity filter as a hazy filtrate. The filtrate was treated with an additional 20.0 g (624 mmol) methanol and stirred for several hours before being filtered again. GC of the colorless clear filtrate indicated complete conversion to the desired 1,1-dimethoxy-1-silacyclopentane. The volatiles were removed from the filtrate by rotary evaporation at 50 °C, 100 torr. The product was purified by vacuum distillation at 65 torr, boiling point 75 °C, amount 60 g, 90% purity. Yield 58%.

[0138] While the application has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been described and that changes can be made in the details within the scope and range of equivalents which should be claimed without departing from the spirit of the application. It is expressly intended that all layers within all ranges actually recited herein-including, for example, all ranges broadly recited in this document-include all narrower ranges falling within the broader range.

Claims

1. A method for preparing Si v O w C x H y F z A method for representing a dielectric film, wherein v + w + x + y + z = 100%, v is 10 to 35 atomic%, w is 10 to 65 atomic%, x is 5 to 40 atomic%, y is 10 to 50 atomic%, and z is 0 to 15 atomic%, the method comprising: A substrate is provided within the reaction chamber; A gaseous reagent is introduced into the reaction chamber, the gaseous reagent comprising at least one structure-forming precursor, the structure-forming precursor comprising an alkoxysilane heterocyclic or acyloxysilane heterocyclic compound and a pore-forming agent, wherein the alkoxysilane heterocyclic or acyloxysilane heterocyclic compound has a structure represented by Formula I: （I）， Where X and Y are independently selected from OR 1 OR 2 and OC(O)R 3 , where R 1-3 Each is independently selected from straight or branched chains C1 to C2. 10 Alkyl, straight-chain or branched C2 to C3 10 Alkenyl, straight-chain or branched C2 to C 10 alkynyl group, C3 to C 10 cycloalkyl, C3 to C 10 Heterocyclic alkyl, C5 to C 10 Aryl and C3 to C 10 heteroaryl; and R 4 It is C3 to C4 atoms that form five- or six-membered saturated rings with Si atoms. 10 alkyldiyl; Energy is applied to the gaseous reagent in the reaction chamber to induce a reaction of the gaseous reagent to deposit an initial film on the substrate, wherein the initial film contains the pore-forming agent; and At least a portion of the pore-forming agent is removed from the initial film to provide a porous dielectric film containing pores and having a dielectric constant of about 2.6 or less.

2. The method of claim 1, wherein the structure forming precursor further comprises a hardening additive.

3. The method according to claim 1, wherein the alkoxysilane heterocyclic or acyloxysilane heterocyclic compound comprises at least one selected from: 1,1-dimethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-di-iso-propoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-di-iso-propoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-di-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-di-iso-propoxy-1-silane, 1,1-dimethoxy-1- Silcyclohexane, 1,1-di-iso-propoxy-1-silcyclohexane, 1,1-di-n-propoxy-1-silcyclohexane, 1-methoxy-1-acetoxy-1-silcyclopentane, 1,1-diacetoxy-1-silcyclopentane, 1-methoxy-1-acetoxy-1-silcyclobutane, 1,1-diacetoxy-1-silcyclobutane, 1-methoxy-1-acetoxy-1-silcyclohexane, 1,1-diacetoxy-1-silcyclohexane, 1-ethoxy-1-acetoxy-1-silcyclopentane, 1-ethoxy-1-acetoxy-1-silcyclobutane and combinations thereof.

4. The method according to claim 1, wherein the pore-forming agent is cyclooctane.

5. The method of claim 2, wherein the hardening additive comprises tetraethoxysilane.

6. The method of claim 2, wherein the hardening additive comprises tetramethoxysilane.

7. The method according to claim 1, wherein it is a plasma-enhanced chemical vapor deposition method.

8. The method according to claim 1, wherein the reaction mixture comprises at least one oxidant selected from O2, N2O, NO, NO2, CO2, water, H2O2, ozone, and combinations thereof.

9. The method of claim 1, wherein the reaction mixture does not contain an oxidizing agent.

10. The method according to claim 1, wherein the reaction chamber in the application step comprises at least one gas selected from He, Ar, N2, Kr, Xe, NH3, H2, CO2 and CO.

11. The method of claim 1, wherein the removal step comprises at least one treatment selected from heat treatment, ultraviolet (UV) treatment, electron beam treatment, gamma radiation treatment, and combinations thereof.

12. The method of claim 11, wherein the UV treatment occurs during at least a portion of the heat treatment.

13. The method of claim 1, wherein the pore-forming agent precursor is selected from the following: a) Having formula C n H 2n Substituted or unsubstituted cyclic hydrocarbons, wherein n = 4 to 14, b) General formula C n H (2n+2)-2y Substituted or unsubstituted hydrocarbons, where n = 2 to 20 and y = 0 to n, where n = 4 to 14. c) Having formula C n H 2n-2x Substituted or unsubstituted monounsaturated or polyunsaturated cyclic hydrocarbons, where x is the number of unsaturated sites in the molecule, and n = 4 to 14. d) Having formula C n H 2n-2 Substituted or unsubstituted bicyclic hydrocarbons, wherein n = 4 to 14, e) Having formula C n H 2n-(2+2x) Substituted or unsubstituted polyunsaturated bicyclic hydrocarbons, where x is the number of unsaturated sites in the molecule, and n = 4 to 14, wherein the number of carbons in the bicyclic structure is between 4 and 12. f) Having formula C n H 2n-4 A substituted or unsubstituted tricyclic hydrocarbon, wherein n = 4 to 14, wherein the number of carbons in the tricyclic structure is between 4 and 12.

14. The method according to claim 1, wherein the pore-forming agent precursor of claim 13 comprises at least one selected from: cyclohexane, 1,2,4-trimethylcyclohexane, 1-methyl-4-(1-methylethyl)cyclohexane, cyclooctane, methylcyclooctane, ethylene, propylene, acetylene, neohexane, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-2,3-butadiene, substituted dienes, p-cymene, cyclooctene, 1,5-cyclooctadiene, cyclohexene, vinylcyclohexane, dimethylcyclohexene, α-terpinene, pinene, limonene, vinylcyclohexene, norbornane, spirononane, camphene, norbornene, norbornadiene, 5-ethylidene-2-norbornene, decahydronaphthalene, adamantane, and combinations thereof.

15. A composition for chemical vapor deposition of dielectric films, wherein the composition comprises an alkoxysilane heterocyclic or acyloxysilane heterocyclic compound having the following formula: （I）， Where X and Y are independently selected from OR 1 OR 2 and OC(O)R 3 , where R 1-3 Each is independently selected from straight or branched chains C1 to C2. 10 Alkyl, straight-chain or branched C2 to C3 10 Alkenyl, straight-chain or branched C2 to C 10 alkynyl group, C3 to C 10 cycloalkyl, C3 to C 10 Heterocyclic alkyl, C5 to C 10 Aryl and C3 to C 10 heteroaryl; and R 4 It is C3 to C4 atoms that form five- or six-membered saturated rings with Si atoms. 10 Alkyl dimethyl compounds, wherein the compounds are substantially free of one or more impurities selected from halides, water, and combinations thereof.

16. The composition of claim 15, wherein the alkoxysilane heterocyclic or acyloxysilane heterocyclic compound comprises at least one selected from: 1,1-dimethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-diiso-propoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-dieth ...methoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-dimethoxy-1-silane, -Silazane, 1,1-di-iso-propoxy-1-silazane, 1,1-di-n-propoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-ethoxy-1-acetoxy-1-silazane, 1-ethoxy-1-acetoxy-1-silazane and combinations thereof.

17. The composition of claim 15, wherein the halide comprises a chloride ion.

18. Use of alkoxysilane heterocyclic or acyloxysilane heterocyclic compounds having Formula I for the deposition of low-k dielectric films by vapor deposition: （I） Where X and Y are independently selected from OR 1 OR 2 and OC(O)R 3 , where R 1-3 Each is independently selected from straight or branched chains C1 to C2. 10 Alkyl, straight-chain or branched C2 to C3 10 Alkenyl, straight-chain or branched C2 to C 10 alkynyl group, C3 to C 10 cycloalkyl, C3 to C 10 Heterocyclic alkyl, C5 to C 10 Aryl and C3 to C 10 heteroaryl; and R 4 It is C3 to C4 atoms that form five- or six-membered saturated rings with Si atoms. 10 Alkyl diol.

19. The use according to claim 18, wherein the compound is substantially free of one or more impurities selected from halides, water, and combinations thereof.

20. The use according to claim 18, wherein the alkoxysilane heterocyclic or acyloxysilane heterocyclic compound comprises at least one selected from the group consisting of: 1,1-dimethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-diiso-propoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-diethoxy-1-silane, 1,1-di-n-propoxy-1-silane, 1,1-diiso-propoxy-1-silane, 1,1-dimethoxy-1-silane, 1,1-di ... -Silazane, 1,1-di-iso-propoxy-1-silazane, 1,1-di-n-propoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-methoxy-1-acetoxy-1-silazane, 1,1-diacetoxy-1-silazane, 1-ethoxy-1-acetoxy-1-silazane, 1-ethoxy-1-acetoxy-1-silazane and combinations thereof.

21. The use according to claim 19, wherein the halide comprises a chloride ion.

22. The use according to claim 21, wherein the chloride ion concentration is less than 50 ppm.

23. The use according to claim 21, wherein the chloride ion concentration is less than 10 ppm.

24. The use according to claim 21, wherein the chloride ion concentration is less than 5 ppm.

25. The use according to claim 18, wherein the vapor deposition is chemical vapor deposition.

26. The use according to claim 25, wherein the chemical vapor deposition is plasma-enhanced chemical vapor deposition.

27. The composition of claim 15, further comprising at least one member selected from carrier gas and oxidant.

28. The composition of claim 27, wherein the member comprises at least one member selected from helium and oxygen.

29. The composition according to claim 15, further comprising at least one hardening additive.

30. The composition of claim 29, wherein the hardening additive comprises at least one tetraalkoxysilane.

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