Additives that improve the properties of dielectric films

Abstract

A method for improving the elastic modulus of a dense organosilica dielectric film (k≧2.7) without adversely affecting the film's electrical properties and with minimal or no reduction in the film's carbon content, comprising: providing a substrate in a reaction chamber; introducing into the reaction chamber a gaseous composition comprising a mixture of an alkyl-alkoxysilane cyclic compound and 5% or less of a specific bis(alkoxy)silane or monoalkoxysilane; and applying energy to the gaseous composition comprising a mixture of an alkyl-alkoxysilane cyclic compound and 5% or less of a specific bis(alkoxy)silane or monoalkoxysilane to deposit an organosilicone film on the substrate, wherein the organosilicone film has a dielectric constant of about 2.70 to about 3.30, an elastic modulus of about 6 to about 30 GPa, and an atomic % carbon of about 10 to about 45 as measured by XPS.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This patent application is an application that entered the national stage under 35 U.S.C. 371 of International Patent Application No. PCT / US2021 / 050736, filed September 16, 2021, which claims priority to U.S. Provisional Patent Application No. 63 / 081,903, filed September 22, 2020. The contents of these applications are incorporated herein by reference in their entireties. [Background technology]

[0002] Described herein is a method for improving the mechanical properties of dense organosilica dielectric films (k≧2.7) without adversely affecting the films' electrical properties and with minimal or no reduction in the films' carbon content. This is achieved by depositing low-k films using precursors containing small amounts of additives (≦5%). No post-deposition treatment of the films is required. Unexpectedly, films obtained by this deposition process were found to exhibit an increase in elastic modulus without adversely affecting the films' electrical properties and with minimal or no reduction in the films' carbon content compared to films deposited from the same precursors in the absence of additives.

[0003] The electronics industry utilizes dielectric materials as insulating layers between circuits and components in integrated circuits (ICs) and related electronic devices. Line dimensions are shrinking to increase the speed and memory storage capacity of microelectronic devices (e.g., computer chips). As line dimensions shrink, the requirements for the insulating properties of interlayer dielectrics (ILDs) become increasingly stringent. A low dielectric constant is required to minimize the RC time constant (where R is the resistance of the conductive line and C is the capacitance of the insulating dielectric interlayer). Capacitance (C) is inversely proportional to the spacing and proportional to the dielectric constant (k) of the interlayer dielectric (ILD). Conventional silica (SiO2) CVD dielectric films, fabricated from SiH4 or TEOS (Si(OCH2CH3)4, tetraethyl orthosilicate) and O2, have a dielectric constant of approximately 4.0 or higher. Several approaches in the industry have attempted to produce silica-based CVD films with low dielectric constants, with the most successful being the doping of insulating silicon oxide films with organic groups to achieve dielectric constants of about 2.7 to about 3.5. These organosilica glasses (or low-k films) are typically deposited as dense (non-porous) films from organosilicon precursors such as methylsilanes or siloxanes and oxidizers such as O2 or NO. Organosilica glasses are referred to herein as OSGs.

[0004] The industry has exhausted most of the low-k compositions suitable for dense films with a dielectric constant of less than 2.7, and as a result, has turned to various porous materials for applications requiring a dielectric constant of less than 2.7. Unfortunately, lowering the dielectric constant by integrating organic groups into the silicon oxide network and / or introducing porosity also significantly reduces the mechanical properties of the film. For example, as taught in U.S. Patent Nos. 8,137,764 and 9,922,818, it has been shown that increasing the proportion of organic groups in the low-k silicon oxide-based network causes the mechanical properties of dense low-k films to decrease much faster than the dielectric constant. Similarly, the mechanical properties of porous low-k films decrease much faster than the dielectric constant as the porosity of the low-k silicon oxide-based network increases (see O'Neill, ML et al., MRS Proceedings Symposium 2006, 914, F01-02, and O'Neill, ML et al., Semiconductor International 2002, 25, 93-100). However, at the most advanced technology nodes, at the bottom of the back-end-of-line (BEOL) layer, low-k materials with the highest possible mechanical properties are required. As device dimensions and pitches shrink at these advanced technology nodes, low-k materials used in the bottom layers of the BEOL must also have the highest possible resistance to plasma and process-induced damage (PID), the lowest possible leakage current, and the highest possible initial breakdown field. Because dense low-k films generally have better mechanical properties and PID resistance than porous low-k films, dense low-k films are typically used in the bottom layers of the BEOL.In addition to the benefits for chip packaging and CMP, the improved mechanical properties of low-k films reduce the roughness of the line edges of patterned structures, reducing pattern collapse and increasing internal mechanical stresses within interconnects, reducing electromigration failures (Darnon, M. et al., "Undulation of sub-100nm Porous Dielectric Structures: A Mechanical Analysis," J. Appl. Phys. 2007, 91, 194103-1-194103-3; Vyas, A. A. et al., "On-Chip Interconnect Conductor Materials for End-of-Roadmap Technology Nodes," IEEE Trans. Nanotechnology 2018, 17, pp. 4-10; Ban, Y. et al., "Electrical Impact of Line-Edge Roughness on Sub-45nm Node Standard Cell," spie09_LER; and Grill, A. et al., "Progress in the Development and Understanding of Advanced Low-k and Ultralow-k Dielectrics for Very Large-Scale Integrated Interconnects—State of the Art,” Appl. Phys. Rev. 2014, 1, 011306). The need for enhanced mechanical properties becomes more critical as pitch shrinks at advanced technology nodes, especially at the bottom layers of downstream processing. This need has driven the search for new high-density, low-k films with relatively high dielectric constants (3.0 ≤ k ≤ 3.5) and the highest possible mechanical properties.

[0005] Plasma or process damage to low-k films, particularly in etching and photoresist strip processes (e.g., NH3-based strip processes), is caused by carbon removal during plasma exposure (see Ryan, E.T. et al., "Property Modifications of Nanoporous pSiCOH Dielectrics to Enhance Resistance to Plasma-Induced Damage," J. Appl. Phys. 2008, 104, 094109; Lionti, K. et al., "Toward Successful Integration of Porous Low-k Materials: Strategies Addressing Plasma Damage," ECS J. Solid State Sci. And Tech. 2015, 4, N3071-N3083; and Yonekura, K. et al., "Low-Damage Damascene Patterning Using Porous Inorganic Low-Dielectric-Constant Materials," Jpn. J. Appl. Phys. 2005, 44, 2976). Carbon depletion transforms the plasma-damaged region from hydrophobic to hydrophilic. Exposing the hydrophilic plasma-damaged region to a dilute HF-based (0.1–0.5 wt.%) wet-chemical post-plasma treatment rapidly dissolves the damaged region and increases the k of the layer (the hydrophobic damaged layer becomes more hygroscopic). During patterning of low-k films (created by etching or photoresist strip processes), exposing the sidewalls of the plasma-damaged pattern to a dilute HF-based post-plasma treatment can result in profile erosion due to plasma and process damage. Profile erosion can lead to the formation of recessed features (leading to metallization defects) and reduced spacing between metal lines (leading to increased capacitance). (See Grill, A., “PECVD Low and Ultralow Dielectric Constant Materials: From Invention and Research to Products.” J. Vac. Sci. Technol. B 2016, 34, 020801).This is particularly problematic in advanced logic devices, where the depth of profile erosion can be a significant percentage of the logic half-pitch. Generally, the higher the carbon content of the low-k film, the shallower the PID depth. Process-induced damage to low-k films and the resulting profile degradation are key issues that device manufacturers must overcome when incorporating low-k materials into ULSI interconnects, especially in the bottom layers of back-end processing.

[0006] Several methods have been reported to improve the mechanical properties of low-k films, including, but not limited to, thermal treatment (U.S. Pat. No. 6,846,515), broadband ultraviolet (UV) curing (U.S. Pat. No. 8,951,342), the use of low-k precursors that inherently result in the deposition of low-k films with superior mechanical properties (U.S. Pat. No. 6,846,515), and the use of curing additives (U.S. Pat. No. 8,137,764).

[0007] Both thermal treatment and broadband UV curing can improve the mechanical properties of as-deposited low-k films. However, both thermal treatment and UV curing undesirably reduce the carbon content of the film, resulting in increased PID. Additionally, both thermal treatment and UV curing require post-processing of the as-deposited film, increasing processing time (reduced throughput), cost (additional hardware, such as UV curing chambers), and complexity. This is especially undesirable for the bottom layer of the back-end of the electronics (BEOL), where advanced IC manufacturers are seeking low-k films that combine maximum resistance to PID with the highest possible mechanical properties without post-processing.

[0008] One of the simplest ways to improve the mechanical properties of low-k films is to use precursors that can deposit low-k films with inherently superior mechanical properties. For example, U.S. Patent No. 6,846,515 shows that the precursor diethoxymethylsilane (DEMS®), sold under the trademark DEMS, deposits low-k films with k values ​​below 3.5 that exhibit unexpectedly superior mechanical properties, as measured by Young's modulus and nanoindentation hardness, compared to alternative precursors trimethylsilane (TMS) and dimethyldimethoxysilane (DMDMOS). This is due to the fact that DEMS®-based films have a higher oxygen content and a lower carbon content than other films with the same dielectric constant. The increased oxygen content is thought to enhance the three-dimensional network connectivity, resulting in improved mechanical properties.

[0009] Additionally, the use of a single low-k precursor inherently results in the deposition of low-k films with excellent mechanical properties (i.e., as-deposited films) without additional post-deposition steps, maximizes throughput (no post-deposition steps required), and eliminates the need for additional hardware (i.e., UV-cured layers), resulting in the simplest process approach with the lowest cost of ownership. However, low-k films deposited from precursors that yield the best mechanical properties inevitably have low total carbon content and therefore limited resistance to PID. While UV curing can further improve the mechanical properties of these films, this also further reduces the carbon content of the films, thus further reducing their resistance to PID. As a result, even the most promising low-k precursors that inherently yield excellent low-k films may not meet the requirements of the most advanced technology nodes in the bottom layer of the back-end of the electrical chain, which require both the highest possible mechanical properties and maximum PID resistance.

[0010] For dense low-k films, it is recognized that increasing the number of silicon-alkoxy groups (e.g., Si-OCH3, Si-OCH2CH3, etc.) in the low-k precursor and decreasing the number of silicon-carbon bonds (e.g., Si-CH3, Si-CH2CH3, etc.) in the precursor increases the dielectric constant and mechanical properties of the as-deposited films, while decreasing the carbon content in the films. Thus, films deposited from precursors containing two silicon-alkoxy groups and one or two silicon-carbon bonds (e.g., DEMS® and DMDMOS) have higher dielectric constants, better mechanical properties, and less carbon than films deposited from precursors containing a single silicon-alkoxy group and up to three silicon-carbon bonds per silicon (e.g., diethyl-isopropoxy-methylsilane and trimethylsilane), films deposited from precursors containing three silicon-alkoxy groups per silicon and up to one silicon-carbon bond per silicon (e.g., triethoxysilane or TES and methyl-triethoxysilane or MTES) have higher dielectric constants, better mechanical properties, and less carbon than films deposited from precursors containing four silicon-alkoxy groups in the precursor and no silicon-carbon bonds per silicon atom (e.g., TEOS) have higher dielectric constants, better mechanical properties, and less carbon.

[0011] This concept was used in U.S. Pat. No. 8,137,764 to improve the mechanical properties of dense low-k films deposited using a mixture of two precursors in the deposition process. One precursor (the curing additive) selected to enhance the film's mechanical properties contained three or four silicon-oxygen bonds per silicon atom and no silicon-carbon bonds, such as TEOS or triethoxysilane (TES). The second low-k precursor contained one or more silicon-carbon bonds, such as DEMS® or DMDMOS. Increasing the proportion of the curing additive (a compound with a high number of silicon-alkoxy groups) improved the film's mechanical properties. A representative example in U.S. Pat. No. 8,137,764 is the deposition of a low-k film from a mixture of TES (50%) and DEMS® (50%). The hardness (1.76 GPa) of the film with k=3.17 deposited from the TES / DEMS® blend was found to be higher than that (1.58 GPa) of the film with the same dielectric constant (k=3.16) deposited from DEMS® alone. The 10% increase in hardness of the TES / DEMS® blend low-k film is presumably due to the higher oxygen content and lower carbon content compared to the DEMS®-only film. This increased oxygen content and decreased carbon content likely improved the three-dimensional network connectivity and mechanical properties.

[0012] As described in U.S. Patent No. 8,137,764, the concept of improving the mechanical properties of dense low-k films by depositing them using a mixture of two precursors during the deposition process has several limitations. First, the curing additive does not contain silicon-carbon bonds, and therefore, the incorporation of silicon-carbon bonds into the network structure is dilute. The invention of U.S. Patent No. 8,137,764 requires a high proportion of curing additive to achieve a measurable increase in the film's mechanical properties (exemplary mixtures are typically 25% to 50% curing additive), which can significantly affect the carbon content of the resulting film. Therefore, low-k films deposited using a combination of a low-k precursor containing silicon-carbon bonds and a curing additive without silicon-carbon bonds can improve mechanical properties. While this strategy can increase the dielectric constant and reduce the carbon content of the film, reducing the carbon content of the film increases plasma and process-induced damage (PID).

[0013] Another limitation of this invention is that the deposition conditions that result in the highest mechanical strength for precursors containing silicon-carbon bonds are typically different from those that result in the highest mechanical strength for curing additives that do not contain silicon-carbon bonds. For example, the highest mechanical strength for precursors containing silicon-carbon bonds may require a lower O2 flow rate during the deposition process, while the highest mechanical strength for curing additives that do not contain silicon-carbon bonds may require a higher O2 flow rate during the deposition process. For mixtures of precursors containing silicon-carbon bonds and curing agents that do not contain silicon-carbon bonds, it is difficult to find optimal deposition conditions that improve mechanical properties at a desired dielectric constant without affecting the film's inherent properties, such as leakage current and initial breakdown field. For example, recent studies have shown that films deposited from a combination of a low-k precursor containing silicon-carbon bonds (e.g., DEMS®) and a curing additive that does not contain silicon-carbon bonds (e.g., TEOS) have higher leakage currents and lower initial breakdown fields than films deposited from low-k precursors containing silicon-carbon bonds (e.g., DEMS®).

[0014] U.S. Patent Application Publication No. 2019 / 0244810 discloses that the modulus of low-k films deposited from organosilanes such as DEMS® can be increased by depositing the films using a mixture of DEMS® and a second silicon-containing precursor, such as isobutyltriethoxysilane (iBTEOS). In this case, iBTEOS acts as a curing additive, resulting in a film with a greater modulus than a film of the same dielectric constant deposited with the DEMS® precursor alone. The curing additive described in U.S. Patent Application Publication No. 2019 / 0244810 contains silicon-carbon bonds and is different from the curing additive described in U.S. Patent No. 8,137,764. Specifically, the curing additive in U.S. Patent Application Publication No. 2019 / 0244810 has the formula R 1 n Si(OR 2 ) 4-n where R 1 is a linear, branched, or cyclic C2-C6 alkyl group, n=1 to 3, and R 2 is a linear, branched, or cyclic C1-C6 alkyl group.

[0015] A limitation of U.S. Patent Application Publication No. 2019 / 0244810 is that the deposition mixture requires a high percentage of curing additive to achieve a measurable increase in the film's mechanical properties. For example, the binary deposition mixture of DEMS® and iBTEOS described in U.S. Patent Application Publication No. 2019 / 0244810, containing 66% to 80% iBTEOS, increased the film's mechanical properties by up to 19% at the same dielectric constant. The high percentage of triethoxysilane derivative (iBTEOS) required results in a dilute film's carbon content, resulting in low-k films with low total carbon content (<10.1 atomic % by XPS), which is presumably less resistant to plasma damage.

[0016] Another limitation of U.S. Patent Application Publication No. 2019 / 0244810 is that the deposition conditions that produce the best mechanical properties for DEMS®-based films are typically different from the deposition conditions that produce the best mechanical properties for the curing additive (iBTEOS). For example, achieving the best mechanical properties for DEMS-based depositions may require a low O2 flow rate during the deposition process, while achieving the best mechanical properties for iBTEOS may require a high O2 flow rate during the deposition process. Finding the optimal deposition conditions for a mixture of precursors that enhances mechanical properties at the desired dielectric constant without affecting the inherent properties of the film, such as leakage current and initial breakdown field, can be challenging.

[0017] Another limitation of U.S. Patent Application Publication No. 2019 / 0244810 is that the very high modulus disclosed for the exemplary binary deposition mixture of DEMS® and iBTEOS was achieved after a post-deposition UV cure treatment of the as-deposited film. This is undesirable because UV curing reduces carbon content, increases film porosity, and leads to greater process-induced damage. Furthermore, post-deposition steps such as UV curing reduce throughput (requiring post-deposition steps) and increase cost of ownership due to the need for additional hardware (i.e., the UV-cured layer).

[0018] Therefore, there is a need for low-k films (k<3.5) that have the highest possible mechanical properties, a high carbon content that provides strong resistance to PID, low leakage current, and a high initial breakdown voltage at a given value of dielectric constant, especially at the bottom layer of line terminations. The as-deposited films should not require post-deposition steps to improve their mechanical properties; i.e., no post-deposition steps such as UV curing are required. Summary of the Invention

[0019] The methods and compositions described herein fulfill one or more of the needs set forth above.

[0020] As taught in U.S. Patent No. 9,922,818, alkyl-alkoxysilane cyclic compounds can be used to deposit low-k films with both high mechanical strength and high total carbon content compared to prior art structure-forming precursors such as DEMS®. However, to meet the requirements for low-k films at the bottom layer of the back-end of the electron beam (BEOL), it is desirable to further enhance the mechanical properties of alkyl-alkoxysilane cyclic films without reducing the carbon content of the films, reducing their resistance to PID, or affecting intrinsic film properties such as film leakage current and initial breakdown field. It is also desirable to do this without post-deposition treatments such as UV curing.

[0021] Low-k films deposited with alkyl-alkoxysilyl precursors in combination with small amounts (≤5%) of specific bisalkoxysilanes or monoalkoxysilanes have been found to enhance the film's elastic modulus with minimal or no effect on other film properties. Specifically, low-k films deposited using alkyl-alkoxysilane precursors in combination with small amounts (≤5%) of specific bisalkoxysilanes or monoalkoxysilanes are expected to exhibit 1) an increase in the film's elastic modulus, 2) minimal or no change in the film's dielectric constant, 3) minimal or no change in the film's XPS carbon content, 4) minimal or no change in the film's resistance to PID, and 5) minimal or no change in the film's leakage current or initial breakdown field, compared to comparable films deposited in the absence of the bisalkoxysilane. This increase in modulus occurs in the as-deposited film, i.e., without any post-deposition treatments such as UV curing.

[0022] Combinations of alkyl-alkoxysilane cyclic precursors with small amounts (≦5%) of certain bisalkoxysilanes or monoalkoxysilanes can be used to deposit dense low-k films with k values ​​of about 2.70 to about 3.50. These films are expected to exhibit increased elastic modulus, minimal or no change in the film's XPS carbon content, minimal or no change in the film's resistance to PID, and minimal or no change in the film's leakage current or initial breakdown field, compared to equivalent films deposited in the absence of the bisalkoxysilane. The increase in elastic modulus occurs without the need for post-deposition processing steps such as UV curing.

[0023] In one aspect, the present disclosure provides a method for producing a dense organosilica film with an increased elastic modulus, the method comprising providing a substrate in a reaction chamber and reacting an alkyl-alkoxysilane compound having a structure given by formula (1): [ka] (where R 1 is hydrogen, linear or branched C1-C 10 Alkyl groups, linear or branched, C2-C 10 Alkenyl groups, linear or branched, C2-C 10 Alkynyl groups, C3-C 10 Cyclic alkyl groups, C3-C 10 Heterocyclic alkyl groups, C5-C 10 Aryl groups and C3-C 10 heteroaryl groups, R 2 is hydrogen, linear or branched C1-C 10 Alkyl groups, linear or branched, C2-C 10 Alkenyl groups, linear or branched, C2-C 10 Alkynyl groups, C3-C 10 Cyclic alkyl groups, C3-C 10 Heterocyclic alkyl groups, C5-C 10 Aryl groups and C3-C 10 heteroaryl groups, R 3 is a C3-C bond that forms a 4-, 5-, or 6-membered ring with a Si atom. 10alkyl diradicals), and 5% or less of a bisalkoxysilane compound having a structure represented by formula (2) or a monoalkoxysilane compound having a structure represented by formula (3), (2) R 6 R 5 Si(OR 4 )2 (3) HR 6 R 5 Si(OR 4 ) (where R 4 is hydrogen, linear or branched C1-C 10 Alkyl groups, linear or branched, C2-C 10 Alkenyl group, linear or branched, C2-C 10 Alkynyl groups, C3-C 10 Cyclic alkyl groups, C3-C 10 Heterocyclic alkyl groups, C5-C 10 Aryl groups, and C3-C 10 heteroaryl groups, R 5 and R 6 is hydrogen, linear or branched C1-C 10 Alkyl groups, linear or branched, C2-C 10 Alkenyl groups, linear or branched, C2-C 10 Alkynyl groups, C3-C 10 Cyclic alkyl groups, C3-C 10 Heterocyclic alkyl groups, C5-C 10 Aryl groups and C3-C 10introducing a gaseous mixture containing an alkyl-alkoxysilane cyclic compound of formula (1) and a bisalkoxysilane compound having a structure given by formula (2) or a monoalkoxysilane compound having a structure given by formula (3) into the reaction chamber; and further introducing a gaseous mixture containing an alkyl-alkoxysilane cyclic compound of formula (1) and a bisalkoxysilane compound having a structure given by formula (2) or a monoalkoxysilane compound having a structure given by formula (3) into the reaction chamber. and applying energy to a gaseous mixture comprising an alkyl-alkoxysilane cyclic compound of Formula (1) and a bisalkoxysilane compound having a structure given by Formula (2) or a monoalkoxysilane compound having a structure given by Formula (3) to induce a reaction of the gaseous mixture comprising an alkyl-alkoxysilane cyclic compound of Formula (1) and a bisalkoxysilane compound having a structure given by Formula (2) or a monoalkoxysilane compound having a structure given by Formula (3) to deposit an organosilica film on the substrate, wherein the organosilica film has a dielectric constant of about 2.70 to about 3.3, an elastic modulus of about 6 to about 28 GPa, and about 10 to about 45 atomic (at.) % carbon as measured by XPS.

[0024] In equations (2) and (3), R 4 , R 5 and R 6 The combination of groups is selected so that the boiling point of the molecule is below 200°C, preferably below 150°C. Additionally, for optimal performance, some of the R groups can be selected to form secondary or tertiary radicals upon homolytic bond dissociation (e.g., SiO-R→SiO·+R·, where R· is a secondary or tertiary radical such as an isopropyl radical, a sec-butyl radical, or a tert-butyl radical). [Brief explanation of the drawings]

[0025] [Figure 1] Figure 1 shows the infrared spectrum of a comparative film deposited from 1-methyl-1-ethoxy-1-silacyclopentane (MPSCP) and the spectrum of a film deposited from a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane.

[0026] [Figure 2] Figure 2 shows the leakage current density versus applied electric field for three low-k films: a comparative film deposited from DEMS®, a comparative film deposited from a mixture of DEMS® and TEOS, and a film made from a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane. DETAILED DESCRIPTION OF THE INVENTION

[0027] Provided herein is a chemical vapor deposition method for producing dense organosilica films with improved mechanical properties, the method comprising the steps of providing a substrate in a reaction chamber; introducing a gaseous composition containing an alkyl-alkoxysilane cyclic compound having a structure given by formula (1), 5% or less of a bisalkoxysilane compound having a structure given by formula (2) or a monoalkoxysilane compound having a structure given by formula (3), a gaseous oxidant such as O or N O, and an inert gas such as He into the reaction chamber; and introducing into the reaction chamber a gaseous composition containing an alkyl-alkoxysilane cyclic compound of formula (1), 5% or less of a bisalkoxysilane compound having a structure given by formula (2) or a monoalkoxysilane compound having a structure given by formula (3). and applying energy to a gaseous mixture comprising a monoalkoxysilane compound having a structure given by Formula (3) to induce a reaction between an alkyl-alkoxysilacyclic compound of Formula (1) and a bisalkoxysilane compound having a structure given by Formula (2) or a monoalkoxysilane compound having a structure given by Formula (3) to deposit an organosilica film on a substrate, the organosilica film having a dielectric constant of about 2.70 to about 3.30, an elastic modulus of about 6 to about 30 GPa, and an atomic % carbon of about 10 to about 45 as measured by XPS, preferably a dielectric constant of about 2.80 to about 3.20, an elastic modulus of about 7 to about 27 GPa, and an atomic % carbon of about 10 to about 40. It has been recognized that OSG films having desirable film properties can also be deposited using gaseous compositions that do not contain an oxidizer.

[0028] The gaseous mixture contains an alkyl-alkoxysilacyclic compound of formula (1), such as 1-methyl-1-ethoxy-1-silacyclopentane (MPSCP), and 5% or less of a bisalkoxysilane compound having a structure given by formula (2), such as bis(isopropoxy)-methyl-butylsilane, or a monoalkoxysilane compound having a structure given by formula (3), such as dimethylisopropoxysilane, and provides unique attributes capable of achieving a relatively low dielectric constant for dense organosilica films with high elastic modulus compared to films deposited from alkyl-alkoxysilacyclic compounds in the absence of the bisalkoxysilane compound having a structure given by formula (2) or the monoalkoxysilane compound having a structure given by formula (3). The addition of up to 5% of a bisalkoxysilane compound having the structure shown in Formula (2) or a monoalkoxysilane compound having the structure shown in Formula (3) to an alkyl-alkoxysilane cyclic compound of Formula (1) increases the elastic modulus of the as-deposited film compared to an equivalent film deposited in the absence of the bisalkoxysilane compound having the structure shown in Formula (2) or the monoalkoxysilane compound having the structure shown in Formula (3), but is expected to show minimal or no change in the film's dielectric constant, minimal or no change in the film's XPS carbon content, minimal or no change in the film's resistance to PID, and minimal or no change in the film's leakage current or initial breakdown field. This increase in elastic modulus occurs in the as-deposited film, i.e., without post-deposition treatment such as UV curing.

[0029] Surprisingly, the addition of up to 5% of a bisalkoxysilane compound having the structure shown in formula (2) or a monoalkoxysilane compound having the structure shown in formula (3) to an alkyl-alkoxysilane cyclic deposition agent of formula (1) increases the modulus without increasing the dielectric constant, decreasing the XPS carbon content, decreasing the expected resistance to PID, increasing the expected leakage current, or decreasing the expected initial breakdown field. To illustrate, the examples in U.S. Pat. No. 8,137,764 demonstrate that a high percentage of curing additive, from 25% to 75%, is required to achieve measurable improvements in the mechanical properties of the film compared to deposition using DEMS® alone. Furthermore, increasing the percentage of curing additive improves the mechanical properties of the resulting film. The curing additives in U.S. Pat. No. 8,137,764 contain three or four silicon-oxygen bonds per silicon atom and no silicon-carbon bonds (such as TEOS or triethoxysilane (TES)), which dilute the carbon content of low-k films, resulting in lower XPS carbon content and lower PID resistance. Thus, increasing the proportion of curing additive improves the film's mechanical properties, decreases the film's carbon content, and increases the film's oxygen content. Similarly, U.S. Patent Application Publication No. 2019 / 0244810 indicates that a higher proportion of curing additive (isobutyltriethoxysilane, iBTEOS) is required—between 66% and 80%—to achieve a measurable increase in film mechanical properties for DEMS®-based depositions. The triethoxysilane-based cure additive iBTEOS of US Patent Application Publication No. 2019 / 0244810 has one silicon-carbon bond and three silicon-alkoxy groups per silicon, thus diluting the carbon content of the film relative to the contribution from the DEMS® precursor, which has only two silicon-alkoxy groups per silicon. This is reflected in the low XPS carbon content (<11%) of all exemplary films in US Patent Application Publication No. 2019 / 0244810.The improved mechanical properties of the example films of U.S. Patent No. 8,137,764 and U.S. Patent Application Publication No. 2019 / 0244810 compared to DEMS®-based films deposited in the absence of a curing agent and with the same dielectric constant are attributed to their higher oxygen content and lower carbon content. The increased oxygen content is believed to improve three-dimensional network connectivity and mechanical properties. However, the lower carbon content of the example films of U.S. Patent No. 8,137,764 and U.S. Patent Application Publication No. 2019 / 0244810 is expected to result in lower resistance to PID. Therefore, it is unexpected that adding 5% or less of a bisalkoxysilane compound having the structure represented by formula (2) or a monoalkoxysilane compound having the structure represented by formula (3) to a monoalkoxyalkyl-alkoxysila cyclic deposition agent increases the film's elastic modulus but has minimal or no increase in dielectric constant, minimal or no increase in XPS carbon content, minimal or no decrease in PID resistance, minimal or no increase in leakage current, and minimal or no decrease in initial breakdown field.

[0030] High-density low-k films deposited according to U.S. Patent No. 8,137,764 exhibit higher leakage currents and lower initial breakdown fields compared to films deposited in the absence of a curing additive. That is, films deposited using a mixture of a curing additive that does not contain silicon-carbon bonds (e.g., TEOS) and a low-k precursor that contains one or more silicon-carbon bonds (e.g., DEMS®) have higher leakage currents and lower initial breakdown fields compared to DEMS®-based films deposited without a curing additive. This is clearly undesirable, especially in the lowest layers of the back-end of the electron beam (BEOL), where IC manufacturers are constantly seeking to reduce leakage currents and increase initial breakdown fields as device scaling continues. On the other hand, dense low-k films deposited in accordance with the present invention from gas mixtures containing an alkyl-alkoxysilane cyclic compound of formula (1), such as MPSCP, and 5% or less of a bisalkoxysilane compound having the structure given by formula (2), such as bis(isopropoxy)-methyl-butylsilane, or a monoalkoxysilane compound having the structure given by formula (3), such as dimethyl-isopropoxysilane, are expected to show minimal or no change in leakage current and initial breakdown field compared to films deposited from the alkyl-alkoxysilane cyclic compound of formula (1) in the absence of the bisalkoxysilane compound having the structure given by formula (2) or the monoalkoxysilane compound having the structure given by formula (3).

[0031] The advantages achieved by the present invention over prior art alkyl-alkoxysilane cyclic based films include, but are not limited to, minimal to no increase in the dielectric constant of the film, minimal to no increase in the XPS carbon content of the film, minimal to no expected decrease in the PID resistance of the film, minimal to no expected increase in leakage current, minimal to no expected decrease in the initial breakdown field, and an increase in the elastic modulus of the film, compared to equivalent films deposited in the absence of a bisalkoxysilane compound having the structure given by Formula (2) or a monoalkoxysilane compound having the structure given by Formula (3).

[0032] The alkyl-alkoxysilane cyclic compounds of formula (1), the bisalkoxysilane compounds of formula (2), and the monoalkoxysilane compounds of formula (3) are preferably substantially free of halide ions. As used herein, the term "substantially free" with reference to halide ions (or halides), such as chloride (i.e., chloride-containing species such as HCl or silicon compounds having at least one Si-Cl bond) and fluoride, bromide, and iodide, refers to less than 5 ppm (by weight) as measured by ion chromatography (IC), preferably less than 3 ppm as measured by IC, more preferably less than 1 ppm as measured by IC, and most preferably 0 ppm as measured by IC. Significant amounts of chloride in the final product can cause degradation of the silicon precursor compound. The gradual degradation of the silicon precursor compound can directly affect the deposition process, making it difficult for semiconductor manufacturers to meet deposition specifications. Furthermore, the rapid decomposition rate of the silicon precursor compound adversely affects its shelf life and stability, making it difficult to guarantee a shelf life of 1 to 2 years. Therefore, the accelerated decomposition of silicon precursor compounds poses safety and performance concerns related to the formation of these flammable and / or pyrophoric gaseous by-products. The alkyl-alkoxysilane cyclic compounds of formula (1), the bisalkoxysilane compounds of formula (2), and the monoalkoxysilane compounds of formula (3) are preferably, for example, Li + , Na + , K. + , Mg 2+ , Ca 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ , Cr 3+As used herein, the term "substantially free" in relation 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, and most preferably less than 0.1 ppm, as measured by ICP-MS. In some embodiments, the alkyl-alkoxysilane cyclic compound of formula (1), the bisalkoxysilane compound of formula (2), and the monoalkoxysilane compound of formula (3) are, for example, free of Li + , Na + , K. + , Mg 2+ , Ca 2+ , Al 3+ , Fe 2+ , Fe 3+ , Ni 2+ , Cr 3+ As used herein, the term "free of metal impurities" in reference to Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr is less than 1 ppm, preferably 0.1 ppm (by weight), and most preferably 0.05 ppm (by weight) as measured by ICP-MS or other analytical method for determining metals.

[0033] Low-k dielectric films are organosilica glass ("OSG") films or materials. Organosilica is employed as a low-k material, for example, in the electronics industry. Material properties depend on the film's chemical composition and structure. Because the composition of the organosilicon precursor gas mixture has a strong influence on the film's structure and composition, it is beneficial to use a mixture of organosilicon precursors that imparts the necessary film properties, so that the amount of porosity required to achieve the desired dielectric constant is added without producing a mechanically unsound film. The methods and compositions described herein provide a means to produce low-k dielectric films with a desirable balance of electrical and mechanical properties, as well as other beneficial film properties, such as high carbon content to provide improved integrated plasma resistance.

[0034] In certain embodiments of the methods and compositions described herein, a layer of silicon-containing dielectric material is deposited on at least a portion of a substrate via a chemical vapor deposition (CVD) process employing a reaction chamber. Accordingly, the method includes providing a substrate in a reaction chamber. Suitable substrates include, but are not limited to, semiconductor materials such as gallium arsenide ("GaAs"), silicon, and silicon-containing compositions such as crystalline silicon, polysilicon, amorphous silicon, epitaxial silicon, silicon dioxide ("SiO"), silicon glass, silicon nitride, fused silica, glass, quartz, borosilicate glass, and combinations thereof. Other suitable materials include metals commonly used in applications such as semiconductors, integrated circuits, flat panel displays, and flexible displays, such as chromium and molybdenum. The substrate may have additional layers such as, for example, silicon, SiO2, organosilicate glass (OSG), fluorinated silicate glass (FSG), boron carbide, 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-inorganic materials and composites, metal oxides such as aluminum oxide, germanium oxide, etc. Additionally, layers can 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.

[0035] The reaction chamber is typically, for example, a thermal CVD or plasma-enhanced CVD reactor, or various aspects of a batch furnace reactor. In one embodiment, a liquid supply system can be utilized. In a liquid delivery formulation, a precursor mixture containing an alkyl-alkoxysilane cyclic compound of formula (1) and 5% or less of a bisalkoxysilane compound of formula (2) or a monoalkoxysilane compound of formula (3) can be delivered in a suitable liquid form, or alternatively, can be employed in a solvent formulation or composition containing the same. Thus, in certain embodiments, the precursor formulation can include solvent component(s) of suitable properties that may be desirable and advantageous in a given end-use application for forming a film on a substrate.

[0036] The method disclosed herein includes introducing a gaseous composition containing an alkyl-alkoxysilane cyclic compound of Formula (1) and 5% or less of a bis-alkoxysilane compound of Formula (2) or a monoalkoxysilane compound of Formula (3) into a reaction chamber. In some embodiments, the composition may include additional reactants, such as oxygen-containing species such as O, O, and NO, gaseous or liquid organic substances, alcohols, CO, or CO. In one embodiment, the reaction mixture introduced into the reaction chamber includes at least one oxidizing agent selected from the group consisting of O, NO, NO, CO, water, HO, ozone, and combinations thereof. In an alternative embodiment, the reaction mixture does not include an oxidizing agent.

[0037] The compositions for depositing the dielectric films described herein comprise from about 95 to about 99.9 weight percent of the alkyl-alkoxysilanocyclic compound of formula (1).

[0038] The compositions for depositing dielectric films described herein include from about 5 to about 0.1 weight percent of a bisalkoxysilane of formula (2).

[0039] The compositions for depositing dielectric films described herein include from about 5 to about 0.1 weight percent of a monoalkoxysilane compound of formula (3).

[0040] In embodiments, the gaseous composition comprising the alkyl-alkoxysilacyclic compound of formula (1) is substantially free or free of halides, such as, for example, chlorides.

[0041] In embodiments, the gaseous composition comprising the bisalkoxysilane compound of formula (2) is substantially free or free of halides, such as, for example, chlorides.

[0042] In embodiments, the gaseous composition comprising the monoalkoxysilane compound of Formula (3) is substantially free or free of halides, such as, for example, chlorides.

[0043] In addition to the gaseous composition containing the alkyl-alkoxysilane cyclic compound of formula (1) and 5% or less of the bisalkoxysilane compound of formula (2) or the monoalkoxysilane compound of formula (3), additional materials can be introduced into the reaction chamber before, during, and / or after the deposition reaction. Such materials include, for example, inert gases (e.g., He, Ar, N, Kr, Xe, etc., which may be employed as carrier gases for less volatile precursors and / or may optionally promote curing of the as-deposited material to provide a more stable final film). Additionally, excited states of the inert gases that occur during plasma-assisted deposition processes can also play an important role in the deposition process.

[0044] Any reagents used, including the alkyl-alkoxysilane cyclic compound of formula (1) and up to 5% of the bisalkoxysilane compound of formula (2) or the monoalkoxysilane compound of formula (3), can be added to the reactor as separate sources or as a mixture. The reagents can be supplied to the reactor system by any number of means, preferably using pressurizable stainless steel vessels equipped with appropriate valves and fittings to allow liquid delivery to the process reactor. Preferably, the precursors are delivered to the process vacuum chamber as gases; i.e., the liquid must be vaporized before being delivered to the process chamber. A carrier gas, such as N2, He, or Ar, may be used to aid in vaporization and transport of the vapor to the reactor.

[0045] The method disclosed herein includes providing energy to a gaseous composition comprising an alkyl-alkoxysilane cyclic compound of Formula (1) and 5% or less of a bisalkoxysilane compound of Formula (2) or a monoalkoxysilane compound of Formula (3) in a reaction chamber to induce a reaction between the alkyl-alkoxysilane cyclic compound of Formula (1) and 5% or less of a bisalkoxysilane compound of Formula (2) or a monoalkoxysilane compound of Formula (3), and depositing an organosilica film on a substrate, the organosilica film having a dielectric constant of about 2.70 to about 3.30 in some embodiments, a dielectric constant of 2.70 to 3.20 in other embodiments, and a dielectric constant of 2.80 to 3.10 in more preferred embodiments, an elastic modulus of about 6 to about 30 GPa, and about 10 to about 45 atomic % carbon as measured by XPS. Energy is applied to the gaseous reagents to induce the alkyl-alkoxysilane cyclic compound of formula (1) and 5% or less of the bisalkoxysilane compound of formula (2) or the monoalkoxysilane compound of formula (3) and other reactants (if present) to react and form a film on the substrate. Such energy can be provided, for example, by plasma, pulsed plasma, helicon plasma, high-density plasma, inductively coupled plasma, remote plasma, hot filament, and thermal (i.e., non-filament) methods. A secondary RF frequency source can be used to modify the plasma characteristics at the substrate surface. Preferably, the film is formed by plasma-enhanced chemical vapor deposition ("PECVD").

[0046] The flow rate of each gaseous reagent is preferably in the range of 5-5000 sccm, more preferably 10-3000 sccm per 300 mm wafer. The actual flow rate required may depend on the wafer size and chamber configuration, and is by no means limited to 300 mm wafers or single wafer chambers.

[0047] In certain embodiments, the film is deposited at a deposition rate of about 5 to about 600 nanometers (nm) per minute, while in other embodiments, the film is deposited at a deposition rate of about 20 to 200 nanometers (nm) per minute.

[0048] The pressure in the reaction chamber during deposition typically ranges from about 0.01 to about 600 torr, or from about 1 to 15 torr.

[0049] Films are preferably deposited to a thickness of 0.001 to 500 microns, although thickness can be varied as needed. Blanket films deposited on unpatterned surfaces have excellent uniformity, with thickness variations across the substrate of 3% or less at 1 standard deviation, and moderate edge exclusion (e.g., the outermost 5 mm of the substrate is not included in statistical uniformity calculations).

[0050] In addition to the inventive OSG products, the present invention also includes processes by which the products are made, methods of using the products, and compounds and compositions useful in preparing the products. For example, a process for making integrated circuits on semiconductor devices is disclosed in U.S. Patent No. 6,583,049, which is incorporated herein by reference.

[0051] The dense organosilica films produced by the disclosed method exhibit excellent resistance to plasma damage, particularly during etching and photoresist strip processes.

[0052] Dense organosilica films produced by the disclosed methods exhibit superior mechanical properties at a given dielectric constant relative to dense organosilica films using alkyl-alkoxysilacyclic compounds of formula (1) in the absence of 5% or less of a bisalkoxysilane compound of formula (2) or a monoalkoxysilane compound of formula (3). The resulting (as-deposited) organosilica films typically have a dielectric constant of about 2.70 to about 3.30 in some embodiments, about 2.80 to about 3.20 in other embodiments, and about 2.70 to about 3.10 in still other embodiments, an elastic modulus of about 6 to about 30 GPa, and about 10 to about 45 atomic % carbon as measured by XPS. In other embodiments, the resulting organosilica films have a dielectric constant of from about 2.70 to about 3.30 in some embodiments, from about 2.80 to about 3.20 in other embodiments, and from about 2.80 to about 3.10 in still other embodiments, an elastic modulus of from about 6 to about 30 GPa, and have from about 10 to about 45 atomic % carbon as measured by XPS.

[0053] The resulting dense organosilica films, once deposited, may be subjected to a post-treatment step. Thus, as used herein, the term "post-treatment" refers to treating the film with energy (e.g., heat, plasma, photons, electrons, microwaves, etc.) or chemicals to further enhance the material properties.

[0054] The conditions under which post-treatment is carried out can vary widely, for example, post-treatment can be carried out under high pressure or in a vacuum environment.

[0055] The UV annealing is preferably carried out under the following conditions:

[0056] The environment may be inert (e.g., nitrogen, CO2, noble gases (He, Ar, Ne, Kr, Xe), etc.), oxidizing (e.g., oxygen, air, diluted oxygen environment, enriched oxygen environment, ozone, nitrous oxide, etc.), or reducing (dilute or enriched hydrogen, hydrocarbons (saturated, unsaturated, linear or branched, aromatic), etc.). The pressure is preferably about 1 Torr to about 1000 Torr. However, a vacuum atmosphere is preferred for thermal annealing as well as any other post-treatment procedures. The temperature is preferably 200 to 500°C, with a temperature ramp rate of 0.1 to 100°C / min. The total UV annealing time is preferably 0.01 min to 12 h.

[0057] The present invention will now be described in more detail with reference to examples, but it should be understood that the present invention is not limited thereto. It is also recognized that the precursors described in the present invention can also be used to deposit porous low-k films that have similar process advantages compared to existing porous low-k films (i.e., a high modulus for a given value of dielectric constant, but with little or no change in the XPS carbon content of the film, and little or no change in resistance to PID, leakage current, or breakdown field). [Example]

[0058] All experiments were performed on a 300 mm AMAT Producer SE depositing films on two wafers simultaneously. Therefore, the precursor and gas flow rates correspond to the flow rates required to deposit films on two wafers simultaneously. The listed RF power per wafer is correct because each wafer processing station has its own independent RF power source. The deposition pressure is correct because both wafer processing stations are maintained at the same pressure.

[0059] Although illustrated and described above with reference to certain specific embodiments and examples, the present invention is not intended to be limited to the details shown. Rather, various modifications in detail may be made within the scope of the appended claims and their equivalents without departing from the spirit of the present invention. For example, all ranges broadly stated herein are expressly intended to include within their scope all narrower ranges that are subsumed within the broader range. It is also recognized that gaseous compositions comprising the disclosed alkyl-alkoxysilane cyclic compound of formula (1) and 5% or less of a bisalkoxysilane compound of formula (2) or a monoalkoxysilane compound of formula (3) can be used as structure formers to deposit porous low-k films that have a high modulus for a given dielectric constant, are expected to exhibit little or no change in the film's XPS carbon content, and exhibit little or no change in PID resistance, leakage current, or breakdown field.

[0060] Film thickness and refractive index were measured using a Woollam Model M2000 spectroscopic ellipsometer. The electrical properties of the films (i.e., dielectric constant, leakage current, and initial breakdown field) were determined using the Hg probe technique on medium-resistivity p-type wafers (range 8-12 Ω-cm). FTIR spectra were measured using a Thermo Fisher Scientific Model iS50 spectrometer equipped with a nitrogen-purged Pike Technologies Map300 to handle 12-inch wafers. FTIR spectra were used to identify the bridging disilylmethylene groups (at 1360 cm). -1 SiCH2Si IR band centered around 1270 cm), terminal silicon methyl group (1270 cm -1 Si(CH3) centered around x IR band), CH x (approx. 2800cm -1 From 3000cm -1 CH x The relative density of various functional groups in the film, such as the relative density of the IR bands, was calculated. For example, the relative density of bridging disilylmethylene groups in the film (i.e., SiCH2Si density), determined by infrared spectroscopy, was calculated at 1360 cm -1The area of ​​the SiCH2Si infrared band centered around 1250 cm -1 From 920cm -1 SiO between x The mechanical properties were measured using a KLA iNano Nanoindenter.

[0061] Compositional data were obtained by X-ray photoelectron spectroscopy (XPS) using a PHI 5600 (73560, 73808) or a Thermo K-Alpha (73846) and are expressed as atomic weight percent. The atomic weight percent (%) values ​​reported in the tables do not include hydrogen.

[0062] Comparative Example 1. Deposition of dense low-k films using 1-methyl-1-isopropoxy-1-silacyclopentane (MPSCP) precursor

[0063] Dense MPSCP-based films were deposited using the following process conditions for a 300 mm fabrication process. The MPSCP precursor was delivered to the reaction chamber via direct liquid injection (DLI) at a flow rate of 2000 mg / min using a He carrier gas flow of 1500 standard cubic centimeters per minute (sccm). Oxygen was delivered to the reaction chamber via a mass flow controller (MFC) at a flow rate of 25 sccm. A 13.56 MHz plasma power of 391 W was applied at a 380 mm showerhead-to-heat pedestal spacing, a pedestal temperature of 400 °C, and a chamber pressure of 7.5 Torr. Various film properties, such as dielectric constant (k), elastic modulus and hardness, infrared spectrum, and atomic weight percent carbon (%C), were obtained as described above and are listed in Table 1.

[0064] [Table 1]

[0065] Comparative Example 2: Deposition of dense low-k films using a mixture of 1-methyl-1-isopropoxy-1-silacyclopentane (MPSCP) and 0.9% bis(isopropoxy)-methyl-butylsilane

[0066] Dense low-k films were deposited using a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane in a 300 mm feature size under the following process conditions: The mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane was delivered to the reaction chamber by direct liquid injection (DLI) at a flow rate of 2000 mg / min with a 1500 sccm He carrier gas flow. Oxygen was delivered to the reaction chamber by an MFC at a flow rate of 25 sccm. A 13.56 MHz plasma was applied at 391 W with a 380 mm showerhead / heat pedestal spacing, a pedestal temperature of 400 °C, and a chamber pressure of 7.5 Torr. Various film properties (e.g., dielectric constant (k), elastic modulus and hardness, infrared spectrum, and atomic weight percent carbon (%C)) were obtained as described above and are listed in Table 1.

[0067] Example 3: Deposition of dense low-k films using DEMS® precursors

[0068] Dense DEMS®-based films were deposited in a 300 mm process using the following process conditions: The DEMS® precursor was delivered to the reaction chamber by direct liquid injection (DLI) at a flow rate of 750 mg / min using a 2250 sccm He carrier gas flow, and a 200 W, 13.56 MHz plasma was applied at a 380 mm showerhead / heat pedestal spacing, a pedestal temperature of 345°C, and a chamber pressure of 10 Torr. Various film properties, such as the dielectric constant (k) and infrared spectrum, were obtained as described above and are shown in Table 2.

[0069] [Table 2]

[0070] Example 4: Deposition of dense low-k films using a mixture of DEMS® and TEOS

[0071] Dense low-k films were deposited using a mixture of DEMS® and TEOS in a 300 mm process under the following process conditions: DEMS® precursor was delivered to the reaction chamber via direct liquid injection (DLI) at a rate of 1625 mg / min using a 1000 sccm He carrier gas flow; TEOS was delivered to the reaction chamber via DLI at a rate of 1750 mg / min using a 1000 sccm He carrier gas flow; oxygen was delivered to the reaction chamber via an MFC at a rate of 50 sccm; and a 13.56 MHz plasma was applied at a 380 mm showerhead / heated pedestal spacing, a 300°C pedestal temperature, 400 W, and a 7.0 Torr chamber pressure. Various film properties (e.g., dielectric constant (k) and infrared spectrum) were obtained as described above and are listed in Table 2.

[0072] From Table 1, it can be seen that the films deposited using a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane have unexpectedly higher moduli relative to films deposited using MPSCP. Within the measurement uncertainty, both films have the same dielectric constant, the same XPS carbon content, and the same relative CH calculated from their respective IR spectra. x Density, Si(CH3) x It was confirmed that the films deposited using a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane had a higher modulus (+5%) than the MPSCP-based films, with little change in other film properties. Consequently, films deposited using a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane are expected to have strong resistance to PID, similar to films deposited using MPSCP alone. Furthermore, films deposited using a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane are expected to have low leakage current and high initial breakdown field, similar to films deposited using MPSCP alone.

[0073] Figure 1 shows the infrared spectra of a comparative film deposited from MPSCP and the spectrum of a film deposited from a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane. The IR spectra are nearly identical, indicating that the film deposited using the mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane shows little change in the identity and relative density of IR-active functional groups relative to the film deposited from MPSCP alone.

[0074] Figure 2 shows the current density versus applied electric field for three low-k films: a comparative film deposited from DEMS®, a comparative film deposited from a mixture of DEMS® and TEOS, and a comparative film deposited from MPSCP. It can be seen that the films deposited from the mixture of DEMS® and TEOS exhibit higher leakage currents (typically current densities at a field strength of 1 MV / cm or 2 MV / cm) and lower initial breakdown fields (typically the field strength at which the current density increases rapidly by at least two orders of magnitude) compared to the films deposited from DEMS®. In contrast, the films described herein, deposited from a mixture of MPSCP and 0.9% bis(isopropoxy)-methyl-butylsilane, exhibit a higher modulus (+5%) and are expected to exhibit leakage currents and initial breakdown fields similar to those of films deposited from MPSCP alone.

[0075] The properties of the films deposited from DEMS® and the mixture of DEMS® and TEOS shown in Figure 2 are shown in Table 2. Although both have the same dielectric constant, the film deposited from the mixture of DEMS® and TEOS has a higher dielectric constant than the film deposited from the mixture of DEMS® and TEOS. x The total carbon content is low, as evidenced by the low relative IR densities of SiCH2Si and SiCH2Si. Furthermore, the relative density of bridging disilylmethylene (SiCH2Si) groups in films deposited from a mixture of DEMS® and TEOS is an order of magnitude lower than in films deposited from DEMS® alone. This suggests that films made from a mixture of DEMS® and TEOS will be less resistant to PID than films deposited from DEMS® alone. Examples of embodiments of the present invention are listed in the following items [Aspect 1] to [Aspect 25]. [Aspect 1] 1. A method for producing a dense organosilica film, the method comprising: providing a substrate in a reaction chamber; Alkyl-alkoxysilacyclic compounds of formula (1)

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Claims

1. 1. A method for producing a dense organosilica film, the method comprising: providing a substrate in a reaction chamber; Alkyl-alkoxysilacyclic compounds of formula (1) 【Chemical 1】 (where R １ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ an aryl group, and C ３ ~C １０ heteroaryl groups, R ２ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ aryl groups, and C ３ ~C １０ heteroaryl groups, R ３ is a C atom that forms a 4-, 5-, or 6-membered cyclic ring with a Si atom. ３ ~C １０ alkyl diradicals), and 5% or less of a bisalkoxysilane having a structure given by formula (2) or a monoalkoxysilane having a structure given by formula (3); (2) R ６ R ５ Si(OR ４ ) ２ (3) HR ６ R ５ Si(OR ４ ) (where R ４ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ aryl groups, and C ３ ~C １０ heteroaryl groups, R ５ and R ６ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ Aryl groups and C ３ ~C １０ heteroaryl groups), introducing into said reaction chamber a gaseous mixture comprising: applying energy to the gaseous mixture in the reaction chamber to induce reaction of the gaseous mixture, thereby depositing the dense organosilica film on the substrate; A method comprising:

2. 2. The method of claim 1, wherein the concentration of one or more impurities selected from the group consisting of halides, metals, and combinations thereof in the alkyl-alkoxysilacyclic compound of formula (1) is less than 5 ppm, the halide concentration being measured by IC and the metal concentration being measured by ICP-MS.

3. 2. The method of claim 1, wherein the concentration of one or more impurities selected from the group consisting of halides, metals, and combinations thereof in the bisalkoxysilane having the structure given by formula (2) is less than 5 ppm, wherein the concentration of halides is measured by IC and the concentration of metals is measured by ICP-MS.

4. 2. The method of claim 1, wherein the concentration of one or more impurities selected from the group consisting of halides, metals, and combinations thereof in the monoalkoxysilane having the structure given by formula (3) is less than 5 ppm, wherein the concentration of halides is measured by IC and the concentration of metals is measured by ICP-MS.

5. 10. The method of claim 1, wherein the organosilica film has a dielectric constant of 2.70 to 3.30, an elastic modulus of 6 to 30 GPa, and an XPS carbon content of 10 to 45%.

6. The method of claim 1 , which is a chemical vapor deposition method.

7. The method of claim 1 , wherein the method is a plasma-enhanced chemical vapor deposition method.

8. The gaseous mixture is O ２ , N ２ O, NO, NO ２ , CO ２ , CO, water, H ２ O ２ 10. The method of claim 1, further comprising at least one oxidizing agent selected from the group consisting of ozone, alcohol, and combinations thereof.

9. The method of claim 1 , wherein the gaseous mixture does not include an oxidizer.

10. The reaction chamber in the application step is ２ , Kr, Xe, CO ２ 10. The method of claim 1, further comprising at least one gas selected from the group consisting of CO and HCl.

11. 10. The method of claim 1, wherein the organosilica film has a refractive index (RI) at 632 nm of 1.3 to 1.

7.

12. The method of claim 1 , wherein the organosilica film is deposited at a rate of 5 nm / min to 600 nm / min.

13. A gaseous composition comprising an alkyl-alkoxysilacyclic compound of formula (1): 【Chemistry 2】 (where R １ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ aryl groups, and C ３ ~C １０ heteroaryl groups, R ２ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ aryl groups, and C ３ ~C １０ heteroaryl groups, R ３ is a C atom that forms a 4-, 5-, or 6-membered cyclic ring with a Si atom. ３ ~C １０ alkyl diradicals), and 5% or less of a bisalkoxysilane having a structure given by formula (2) or a monoalkoxysilane having a structure given by formula (3); (2) R ６ R ５ Si(OR ４ ) ２ (3) HR ６ R ５ Si(OR ４ ) (where R ４ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ aryl groups, and C ３ ~C １０ heteroaryl groups, R ５ and R ６ is hydrogen, linear or branched C １ ~C １０ Alkyl groups, linear or branched C ２ ~C １０ Alkenyl group, linear or branched C ２ ~C １０ Alkynyl group, C ３ ~C １０ Cyclic alkyl group, C ３ ~C １０ Heterocyclic alkyl group, C ５ ~C １０ Aryl groups and C ３ ~C １０ heteroaryl groups), A gaseous composition comprising:

14. 2. The composition of claim 1, wherein the concentration of chloride ions in the alkyl-alkoxysilacyclic compound of formula (1) is less than 5 ppm as measured by IC.

15. 15. The composition of claim 14, wherein chloride ions, if present, are present at a concentration of 50 ppm or less as measured by IC.

16. 16. The composition of claim 15, wherein the chloride ions, if present, are present at a concentration of 10 ppm or less as measured by IC.

17. 17. The composition of claim 16, wherein the chloride ions, if present, are present at a concentration of 5 ppm or less as measured by IC.

18. 14. The composition of claim 13, wherein the concentration of chloride ions in the bisalkoxysilane having the structure given by formula (2) is less than 5 ppm as measured by IC.

19. 20. The composition of claim 18, wherein chloride ions, if present, are present at a concentration of 50 ppm or less as measured by IC.

20. 20. The composition of claim 19, wherein the chloride ions, if present, are present at a concentration of 10 ppm or less as measured by IC.

21. 21. The composition of claim 20, wherein the chloride ions, if present, are present at a concentration of 5 ppm or less as measured by IC.

22. 14. The composition of claim 13, wherein the concentration of chloride ions in the monoalkoxysilane having the structure given by formula (3) is less than 5 ppm as measured by IC.

23. 23. The composition of claim 22, wherein chloride ions, if present, are present at a concentration of 50 ppm or less as measured by IC.

24. 24. The composition of claim 23, wherein the chloride ions, if present, are present at a concentration of 10 ppm or less as measured by IC.

25. 25. The composition of claim 24, wherein the chloride ions, if present, are present at a concentration of 5 ppm or less as measured by IC.

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