Silicon nitride film with high nitrogen content

Abstract

Methods for depositing silicon nitride films with higher nitrogen content are described. Certain methods include: exposing a substrate to a silicon nitrogen precursor and an ammonia plasma to form a flowable polymer; and, then curing the polymer to form a silicon nitride film. Certain methods cure the flowable polymer without using a UV curing process. Films produced by the above methods are also described.

Description

[0001] This application is a divisional application of the invention patent application with application number 201880044202.2 filed on July 5, 2018 and invention name “Silicon nitride film with high nitrogen content”. Technical Field

[0002] The present disclosure relates generally to methods of depositing thin films. In particular, the present disclosure relates to processes for depositing high nitrogen content silicon nitride films. Background Art

[0003] Deposition of thin films on substrate surfaces is an important process in a variety of industries, including semiconductor processing, diffusion barrier coating, and dielectrics for magnetic read / write heads. In some semiconductor industries, in particular, miniaturization benefits from a high level of control over thin film deposition to produce conformal coatings on high aspect ratio structures. One method for depositing thin films in a relatively controlled and conformal deposition manner is chemical vapor deposition (CVD). CVD involves exposing a substrate (e.g., a wafer) to one or more precursors that react to deposit a film onto the substrate. Flowable chemical vapor deposition (FCVD) is a type of CVD that allows the deposition of flowable films, particularly for gap fill applications.

[0004] SiN flowable films are commonly used for gap filling applications. Currently, such films are produced by trisilylamine (TSA) with NH3 in radical form as co-reactants. The initially deposited films obtained by the TSA process include Si and N as the main components. These films typically have a nitrogen-to-silicon ratio in the range of 0.4:1 to 0.7:1. Films with higher nitrogen content can be used in patterning applications to solve etching selectivity issues.

[0005] Therefore, new deposition chemistries are needed to allow deposition of SiN films with higher nitrogen contents. Summary of the invention

[0006] One or more embodiments of the present disclosure are directed to a method for depositing a SiN film. The method includes exposing a substrate to a silicon nitride precursor and NH3 plasma to deposit a flowable SiN polymer; and curing the flowable SiN polymer to form a cured SiN film. In these embodiments, the silicon nitride precursor includes one or more of the following:

[0007]

[0008] wherein R1-R5 are independently H or C1-C4 alkyl.

[0009] Additional embodiments of the present disclosure are directed to a method of depositing a SiN film. The method includes exposing a substrate maintained at a temperature of less than or equal to 25° C. to a silicon nitrogen precursor and NH3 plasma to deposit a flowable SiN polymer; and curing the flowable SiN polymer to form a cured SiN film, wherein the ratio of nitrogen to silicon atoms in the cured SiN film is greater than about 1.0. In these embodiments, the silicon nitrogen precursor includes one or more of the following:

[0010]

[0011] wherein R1-R5 are independently H or methyl, and provided that at least one of R1-R5 is methyl.

[0012] Further embodiments of the present disclosure are directed to a cured SiN film formed by exposing a substrate to a silicon nitrogen precursor and NH3 plasma at a temperature less than or equal to about 25°C without UV light curing. In these embodiments, the ratio of nitrogen to silicon atoms in the cured SiN film is in the range of about 1.0 to about 1.5, and the silicon nitrogen precursor includes one or more of the following:

[0013]

[0014] wherein R1-R5 are independently H or C1-C4 alkyl. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above briefly summarizes the manner in which the above-described features of the present invention can be understood in detail, as well as a more specific description of the present invention, which can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate typical embodiments of the present invention and should not be considered as limiting the scope of the present invention, as the present invention may allow other equally effective embodiments.

[0016] Figure 1 A schematic cross-sectional view showing a substrate according to one or more embodiments of the present disclosure;

[0017] Figure 2A illustrates deposition of a flowable film according to one or more embodiments of the present disclosure; and

[0018] Figure 2B The formation of a cured film according to one or more embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0019] Before describing several exemplary embodiments of the present invention, it should be understood that the present invention is not limited to the details of construction or process steps set forth in the following description. The present invention is capable of other embodiments and of being practiced or carried out in various ways.

[0020] As used in this specification and the appended claims, the term "substrate" refers to a surface, or portion of a surface, upon which a process acts. Unless the context clearly indicates otherwise, one skilled in the art will also understand that reference to a substrate may also refer to only a portion of a substrate. In addition, reference to a deposition on a substrate may mean both a bare substrate and a substrate having one or more films or features formed or deposited thereon.

[0021] As used herein, "substrate" refers to any substrate or material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, depending on the application, substrate surfaces on which processing can be performed include: materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire; and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydrogenate, anneal, UV cure, electron beam cure, and / or bake the substrate surface. In addition to performing processing directly on the surface of the substrate itself, in the present invention, any of the disclosed film processing steps may also be performed on an underlying layer that is formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is intended to include such underlying layers as referred to in the context. Thus, for example, when a film / layer or part of a film / layer has been deposited on a substrate surface, the exposed surface with the newly deposited film / layer becomes the substrate surface.

[0022] One or more embodiments of the present disclosure are directed to methods for depositing silicon nitride films using novel silicon nitrogen precursors. Embodiments of the present disclosure utilize a variety of CVD processes. In some embodiments, a plasma enhanced CVD (PECVD) process is used. The PECVD process is similar to a CVD process commonly known in the art combined with supplying one or more reactants in a plasma manner. Without being limited to theory, the PECVD process utilizes free radicals present in plasma reactants to facilitate reactions that would not otherwise be obtained through conventional thermal reactions. In some embodiments, a flowable CVD (FCVD) process is used. The FCVD process is similar to a CVD process commonly known in the art, with the difference that the deposited material is "flowable" so that the material moves along the substrate surface to fill substrate features. The flowable material deposited in the FCVD process is generally cured to solidify the flowable material into a solidified film that is no longer able to move along the substrate surface.

[0023] In some embodiments, the film deposition process includes exposing the substrate to a silicon nitrogen precursor and NH 3 plasma to deposit a flowable SiN polymer. The flowable polymer is cured to form a cured SiN film.

[0024] Figure 1 A cross-sectional view of a substrate 100 is shown, with the substrate 100 having two features 110 (e.g., grooves or through holes). The number of features in the figure is for illustrative purposes only and should not be considered as limiting the scope of the present disclosure. Those skilled in the art will appreciate that there may be no features or any number of features. The shape of the feature 110 may be any suitable shape, including but not limited to grooves and cylindrical through holes. As used in this regard, the term "feature" means any intentional surface irregularity with an aspect ratio greater than or equal to about 2:1. The aspect ratio of the feature is the ratio of the depth D of the feature to the width W of the feature. A higher aspect ratio feature will have a narrower / longer shape than a lower aspect ratio feature. In some embodiments, the feature has an aspect ratio greater than or equal to about 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1 or 30:1. For the purposes of the present disclosure, the groove has a top, two sidewalls, and the two sidewalls extend downward from the surface to the bottom. As illustrated, each sidewall may be substantially orthogonal to the bottom, or may be inclined at an angle other than 90 degrees relative to the bottom such that the opening at the surface is larger than the opening at the lower portion of the feature.

[0025] refer to Figure 1 , substrate 100 may include two materials; a first material 120 and a second material 130. In some embodiments, first material 120 and second material 130 are the same material, such that feature 110 is bounded on the sides and bottom by the same material. In some embodiments, first material 120 and second material 130 are different, such that bottom 115 of feature is a different material than sidewalls 111, 112 of feature 110.

[0026] The feature 110 extends from the substrate surface 125 into the substrate 100 by a distance D to a bottom 115. The feature 110 has a first sidewall 111 and a second sidewall 112, defining a width W of the feature 110. The open area formed by the sidewalls and the bottom is also called a gap. The material filling the gap is called a gap filler.

[0027] refer to Figure 2A and 2BOne or more embodiments of the present disclosure are directed to film deposition processes that utilize a silicon nitrogen precursor and a plasma (e.g., ammonia). In some embodiments, the silicon nitrogen precursor and the plasma reactants are flowed into a processing chamber simultaneously. The silicon nitrogen precursor and the plasma can be mixed in the processing chamber, or before entering the processing chamber. In some embodiments, the reactants are flowed into the processing chamber sequentially to avoid gas phase mixing of the precursor and the plasma reactants.

[0028] In some embodiments, the silicon nitride precursor includes a compound having the general formula (I):

[0029]

[0030] Wherein each of the R substituents (R1-R5) is independently selected from H or C1-C4 alkyl. For the purpose of the present disclosure, C1-C4 alkyl means any group with 1 to 4 carbon atoms. Examples of C1-C4 alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, and tertiary butyl groups. In some embodiments, all groups of the R groups are the same. In some embodiments, at least one of the R substituents is a methyl group. In some embodiments, at least one of the R groups is a non-hydrogen atom. In some embodiments, at least one of the R groups includes an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a secondary butyl group, or a tertiary butyl group.

[0031] In some embodiments, the silicon nitride precursor consists essentially of a compound of formula (I), wherein R1-R5 are each independently H or C1-C4 alkyl. As used in this context, the term "consisting essentially of" means that the reactive species in the silicon nitride precursor is greater than or equal to about 95% of the specified species on a molar basis. In some embodiments, the silicon nitride precursor includes one or more of the following:

[0032]

[0033] In some embodiments, the silicon nitrogen precursor includes a compound having the general formula (II):

[0034]

[0035] Wherein each of R substituents (R1-R5) is independently selected from H or C1-C4 alkyl. The example of C1-C4 alkyl includes but is not limited to methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl and tertiary butyl groups. In some embodiments, all R groups are the same. In some embodiments, at least one of the R substituents is a methyl group. In some embodiments, at least one of the R groups is a non-hydrogen atom. In some embodiments, at least one of the R groups includes an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a secondary butyl group or a tertiary butyl group.

[0036] In some embodiments, the silicon nitrogen precursor consists essentially of a compound of formula (II), wherein R1-R5 are each independently H or a C1-C4 alkyl group. In some embodiments, the silicon nitrogen precursor comprises one or more of the following:

[0037]

[0038] In some embodiments, the silicon nitrogen precursor includes a compound having the general formula (III):

[0039]

[0040] Wherein each of R substituents (R1-R2) is independently selected from H or C1-C4 alkyl. The example of C1-C4 alkyl includes but is not limited to methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl and tertiary butyl groups. In some embodiments, all R groups are the same. In some embodiments, at least one of the R substituents is a methyl group. In some embodiments, at least one of the R groups is a non-hydrogen atom. In some embodiments, at least one of the R groups includes an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a secondary butyl group or a tertiary butyl group.

[0041] In some embodiments, the silicon nitrogen precursor consists essentially of a compound of formula (III), wherein R1-R2 are independently H or C1-C4 alkyl. In some embodiments, the silicon nitrogen precursor comprises one or more of the following:

[0042]

[0043] The silicon nitrogen precursor may be provided in one or more pulses or continuously. The flow rate of the precursor may be any suitable flow rate, including but not limited to the following flow rates: in the range of about 1 sccm to about 1000 sccm, or in the range of about 2 sccm to about 500 sccm, or in the range of about 3 sccm to about 200 sccm, or in the range of about 5 sccm to about 100 sccm, or in the range of about 10 sccm to about 50 sccm, or in the range of about 15 sccm to about 25 sccm. In some embodiments, the flow rate of the precursor is less than or equal to about 50 sccm, about 45 sccm, about 40 sccm, about 35 sccm, about 30 sccm, about 25 sccm, about 20 sccm, or about 15 sccm. The precursor may be provided at any suitable pressure including, but not limited to, pressures in the range of about 5 mTorr to about 25 Torr, or in the range of about 100 mTorr to about 20 Torr, or in the range of about 5 Torr to about 20 Torr, or in the range of about 50 mTorr to about 2000 mTorr, or in the range of about 100 mTorr to about 1000 mTorr, or in the range of about 200 mTorr to about 500 mTorr.

[0044] As used herein, a "pulse" or "dose" is intended to refer to the amount of a reactant that is intermittently or discontinuously introduced into a processing chamber. The amount of a particular compound within each pulse may vary over time, depending on the pulse duration. Any particular reactant may include a single compound or a mixture / combination of two or more compounds.

[0045] The duration of each pulse / dose is variable and can be adjusted to accommodate, for example, the volume capacity of the processing chamber and the capabilities of the vacuum system coupled to the processing chamber. In addition, the dosing time of the reactants can vary depending on factors such as the flow rate of the reactants, the temperature of the reactants, the type of control valve, the type of processing chamber used, and the ability of the components of the reactants to react and form a suitable film. The dosing time can also vary depending on the type of film formed and the geometry of the substrate. The dosing time should be long enough to provide a reactant volume sufficient to adsorb / chemisorb onto substantially the entire surface of the substrate and form a layer of reactive species thereon.

[0046] In some embodiments, the reactant includes an inert gas, a diluent gas, and / or a carrier gas. The inert gas, diluent gas, and / or carrier gas may be mixed with the reactive species and may be pulsed or have a continuous flow. In some embodiments, the carrier gas flows into the processing chamber at a fixed flow rate in the range of about 1 to about 20,000 sccm. The carrier gas may be any gas that does not interfere with film deposition. For example, the carrier gas may include one or more of the following: argon, helium, hydrogen, nitrogen, neon, or the like, or a combination of the above gases. In one or more embodiments, the carrier gas is mixed with the reactive species before flowing into the processing chamber.

[0047] The ammonia plasma can be generated at any suitable location. The plasma can be generated or ignited within the processing chamber (e.g., direct plasma), or the plasma can be generated outside the processing chamber and flowed into the processing chamber (e.g., remote plasma). In some embodiments, the plasma is generated outside the processing chamber, for example, by a remote plasma source. In some embodiments, the generation of the remote plasma can occur upstream of the deposition chamber so that the reactive species are in direct contact with the deposited film.

[0048] The plasma is described for an ammonia plasma. However, one skilled in the art will appreciate that the plasma can have reactive species other than ammonia. For example, the plasma can include nitrogen or hydrazine. The ammonia plasma can be generated via any suitable plasma generation process or technique known to one skilled in the art. For example, the plasma can be generated by one or more of a microwave (MW) frequency generator or a radio frequency (RF) generator. The plasma frequency can be adjusted depending on the specific reactive species used. Suitable frequencies include, but are not limited to, 2 MHz, 13.56 MHz, 40 MHz, 60 MHz, and 100 MHz.

[0049] In some embodiments, the NH plasma is generated using a remote plasma source. In some embodiments, the plasma power is less than or equal to about 300 W. In one or more embodiments, the plasma power is less than or equal to about 250 W, 200 W, 150 W, 100 W, 50 W, or 25 W. In some embodiments, the plasma power is in the range of about 10 W to about 200 W, or in the range of about 25 W to about 175 W, or in the range of about 50 W to about 150 W.

[0050] In some embodiments, a plasma is generated in a remote plasma source and flowed into a processing region of a processing chamber such that free radicals present in the plasma can react with a silicon nitride precursor or a substrate or a film on the substrate. In some embodiments, the remote plasma is configured such that there are a greater number of free radicals than ions in the processing region of the processing chamber.

[0051] In some embodiments, a hot filament is used to generate NH3 radicals instead of or in addition to a plasma source. As used in this specification and in the appended claims, the term "hot filament" means an element that can be heated to a temperature sufficient to generate free radicals in a fluid flowing through the element. In some embodiments, the hot filament is one or more metal filaments (e.g., tungsten). In some embodiments, the hot filament is a filament comprising one or more of the following: tungsten, tantalum, or ruthenium. In some embodiments, the temperature of the filament is maintained in a range of about 200°C to about 1500°C, or in a range of about 1000°C to about 1500°C, or in a range of about 1100°C to about 1400°C. In some embodiments, the temperature of the filament is maintained at a temperature below about 1500°C, 1400°C, 1300°C, or 1200°C. In embodiments in which a hot filament is used to generate free radical species, the substrate is maintained at a cold temperature (i.e., less than or equal to about 25°C).

[0052] During deposition, the temperature of the substrate 100 can be controlled. In some embodiments, the substrate 100 is cooled to a temperature of less than or equal to about 25°C. Such cooling can be accomplished by any suitable means, including but not limited to: changing the temperature of the substrate support, or flowing a cooling gas to the substrate surface. In some embodiments, the substrate support includes a cooler that can be controlled to change the substrate temperature by conduction. In one or more embodiments, the gas (including reactants and / or carrier gases) used is cooled to locally change the substrate temperature. In some embodiments, the cooler is positioned in the chamber adjacent to the substrate surface to change the substrate temperature by convection.

[0053] refer to Figure 2A , the substrate 100 is exposed to a silicon nitride precursor and a reactant to form a flowable film 210 on the substrate. Figure 2A The flowable membrane 210 illustrated in FIG. 2 is only in character; however, one skilled in the art will appreciate that this is for illustration purposes only.

[0054] The flowable film 210 can be deposited on a substrate maintained at any suitable temperature. In some embodiments, the substrate is maintained at a temperature in the range of about -100°C to about 25°C, or in the range of about -75°C to about 20°C, or in the range of about -50°C to about 10°C, or in the range of about -25°C to about 0°C. Without being limited by theory, the temperature is maintained at a low temperature to promote polymerization of the silicon nitride precursor. In some embodiments, the substrate is maintained at a temperature below about 25°C, 20°C, 15°C, 10°C, 5°C, 0°C, -10°C, -20°C, -30°C, -40°C, -50°C, -60°C, -70°C, -80°C, or -90°C.

[0055] The flowable film 210 can be formed at any suitable pressure. In some embodiments, the pressure used to form the flowable film 210 is a pressure in the range of about 0.5 Torr to about 50 Torr, or in the range of about 0.75 Torr to about 25 Torr, or in the range of about 1 Torr to about 10 Torr, or in the range of about 2 Torr to about 8 Torr, or in the range of about 3 Torr to about 6 Torr.

[0056] refer to Figure 2B , after deposition, the flowable film 210 is cured to form a cured film 220. The flowable film 210 can be cured by any suitable means. In some embodiments, the flowable film 210 is cured by exposure to free radicals in a plasma or from a hot filament. In some embodiments, the flowable film 210 is cured by exposure to ultraviolet (UV) radiation. In some embodiments, the flowable film 210 is cured without the use of UV radiation. In some embodiments, the flowable film 210 is cured substantially only by exposure to free radicals. As used in this specification and the appended claims, the term "cured substantially only by exposure to free radicals" means that greater than or equal to about 90%, 95%, 98%, or 99% of the flowable film 210 is cured using free radicals.

[0057] In some embodiments, the cured film undergoes a post-deposition treatment process. In some embodiments, the post-deposition treatment process includes at least one of polishing, etching, reduction, oxidation, hydrogenation, annealing, UV curing, electron beam curing, or baking the substrate surface or any deposited film.

[0058] Referring to FIG. 2B , a cured film 220 is formed on substrate 100. Within the gap, a portion of the film of gap filler is formed along the sidewalls 111 , 112 and bottom 115. As this film forms, if the top of the gap closes before the bottom is filled with the gap filler material, there is a possibility of seam formation. Seam formation is more likely to occur in higher aspect ratio features because the film at the top of the feature tends to pinch closed, causing the void to be enclosed in the deposited gap filler. As used in this regard, the term "seam" means any space or void between the sidewalls 111 , 112, where the volume of the void space is greater than 1% of the volume of the gap or other feature. In some embodiments, the deposited cured SiN film is substantially seam-free.

[0059] The cured films of the disclosed embodiments have a higher ratio of nitrogen atoms to silicon atoms. In some embodiments, the cured SiN film has a ratio of nitrogen atoms to silicon atoms greater than or equal to about 0.7, 0.8, 0.9, or 1.0. In some embodiments, the cured SiN film has a ratio of nitrogen atoms to silicon atoms in the following range: a lower limit of about 1.0, 1.1, 1.2, or 1.33, and an upper limit of about 1.33, 1.4, or 1.5. In some embodiments, the cured SiN film is substantially free of carbon atoms. As used in this regard, the term "substantially free of carbon atoms" means that, on an atomic basis, carbon atoms constitute less than or equal to about 5%, 2%, or 1% of the atoms in the cured film.

[0060] References in this specification to "one embodiment", "certain embodiments", "one or more embodiments", or "an embodiment" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment are incorporated into at least one embodiment of the present disclosure. Therefore, the appearance of words such as "in one or more embodiments", "certain embodiments", "in one or more embodiments", or "in an embodiment" throughout this specification does not necessarily refer to the same embodiment of the present disclosure. Furthermore, the specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0061] Although the present disclosure has been described herein with reference to specific embodiments, it will be appreciated by those skilled in the art that these embodiments are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations may be made to the methods and apparatus of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure may include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A method for depositing a SiN film, comprising: exposing the substrate to a silicon nitrogen precursor and NH3 plasma to deposit a flowable SiN polymer; and curing the flowable SiN polymer to form a cured SiN film; The silicon-nitrogen precursor comprises one or more of the following: wherein R1-R5 are independently H or C1-C4 alkyl; or wherein R1-R2 are independently H or C1-C4 alkyl, The cured SiN film has a ratio of nitrogen atoms to silicon atoms of greater than or equal to 0.

7. 2 . The method of claim 1 , wherein at least one R group in the silicon nitride precursor is a methyl group.

3. The method of claim 1, wherein the silicon nitride precursor comprises one or more of the following:

4. The method of claim 1, wherein the silicon nitride precursor consists essentially of Composition, wherein R1-R5 are independently H or C1-C4 alkyl.

5. The method of claim 4, wherein the silicon nitride precursor comprises one or more of the following:

6. The method of claim 1, wherein the silicon nitride precursor consists essentially of Composition, wherein R1-R2 are independently H or C1-C4 alkyl.

7. The method of claim 6, wherein the silicon nitride precursor comprises one or more of:

8. The method of claim 1, wherein the plasma is generated using a remote plasma source.

9. The method of claim 1, wherein the flowable SiN polymer is cured by exposure to a plurality of free radicals in the plasma.

10. The method of claim 1, further comprising a post-deposition treatment comprising UV radiation exposure or annealing.

11. The method of claim 1, wherein the cured SiN film has a ratio of nitrogen atoms to silicon atoms greater than or equal to 1.

0.

12. The method of claim 1, wherein the cured SiN film has a ratio of nitrogen atoms to silicon atoms ranging from 1.0 to 1.

5.

13. The method of claim 1, wherein the substrate is maintained at a temperature less than or equal to 65°C.

14. The method of claim 13, wherein the substrate is maintained at a temperature in the range of -100°C to 65°C.

15. The method of claim 1, wherein the cured SiN film is substantially free of carbon atoms.

16. A method for depositing a SiN film, comprising: exposing the substrate maintained at a temperature less than or equal to 25° C. to a silicon nitrogen precursor and NH 3 plasma to deposit a flowable SiN polymer; and curing the flowable SiN polymer to form a cured SiN film; The ratio of nitrogen to silicon atoms in the cured SiN film is greater than 1.0, and the silicon-nitrogen precursor comprises one or more of the following: wherein R1-R5 are independently H or CH3, provided that at least one of R1 to R5 is methyl; or wherein R1-R2 are independently H or CH3, provided that at least one of R1 to R2 is methyl.

17. A cured SiN film formed by exposing a substrate to a silicon nitrogen precursor and NH3 plasma at a temperature less than or equal to 65°C without UV radiation curing, wherein the ratio of nitrogen to silicon atoms in the cured SiN film is in the range of 1.0 to 1.5, and the silicon nitrogen precursor comprises one or more of the following: Wherein R1-R5 are independently H or C1-C4 alkyl; wherein R1-R5 are independently H or C1-C4 alkyl; or wherein R1-R2 are independently H or C1-C4 alkyl.

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