Deposition with modification step for sputtering and / or composition modification

Abstract

Examples are disclosed that relate to chemical vapor deposition (CVD) with a plasma-based modification step. One example provides a method of performing CVD. The method comprises performing a plurality of CVD cycles to form a silicon-containing film on a substrate. Each CVD cycle of the plurality of CVD cycles comprises performing a CVD step by exposing the substrate to a flow of a silicon-containing precursor under conditions configured to convert the silicon-containing precursor into the silicon-containing film on the substrate. Each CVD cycle further comprises, after performing the CVD step, performing a modification step by using a plasma to impinge ions on the silicon-containing film to at least modify a profile of the silicon-containing film or modify a composition of the silicon-containing film.

Description

DEPOSITION WITH MODIFICATION STEP FOR SPUTTERING AND / ORCOMPOSITION MODIFICATIONBACKGROUND

[0001] Semiconductor device fabrication processes involves many steps of material deposition, patterning and removal to form integrated circuits on substrates. Various methods can be used to deposit films of materials onto a substrate. As an example, chemical vapor deposition (CVD) deposits a film by directing a continuous flow of precursor compound(s) over a substrate under conditions configured to convert the precursor compound(s) into a film. In various examples, the precursor compound(s) can be converted to a film using heat (thermal CVD) or plasma (plasma-enhanced CVD).SUMMARY

[0002] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

[0003] Examples are disclosed that relate to chemical vapor deposition (CVD) with a plasma-based modification step. One example provides a method of performing CVD. The method comprises performing a plurality of CVD cycles to form a silicon- containing film on a substrate. Each CVD cycle of the plurality of CVD cycles comprises performing a CVD step by exposing the substrate to a flow of a silicon- containing precursor under conditions configured to convert the silicon-containing precursor into the silicon-containing film on the substrate. Each CVD cycle further comprises performing a modification step by using a plasma to impinge ions on the silicon-containing film to at least modify a profile of the silicon-containing film or modify a composition of the silicon-containing film.

[0004] In some such examples, the modification step comprises forming the plasma an inert gas to change a profile of a reentrant structure of the silicon-containing film by sputtering.

[0005] In some such examples, the silicon-containing precursor alternatively or additionally comprises a silane-based precursor, and the silicon-containing film comprises silicon oxide, silicon oxynitride, or silicon nitride.

[0006] In some such examples, the plasma of the modification step alternatively or additionally is formed using radiofrequency energy comprising a lower frequency energy component of 3 MHz or lower and a higher frequency energy component of 3 MHz to 300 MHz.

[0007] In some such examples, the plasma of the CVD step alternatively or additionally is formed using radiofrequency energy comprising a high frequency component of 3 MHz to 300 MHz and omits a low frequency component.

[0008] In some such examples, the silicon-containing film deposited in the CVD step alternatively or additionally is a silicon oxide film, the silicon-containing precursor comprises tetraethlyorthosilicate, and the modification step comprises nitridating the silicon oxide film.

[0009] In some such examples, nitridating the silicon oxide film alternatively or additionally comprises forming the plasma using one or more of ammonia, molecular nitrogen, hydrazine, or a CN-containing species.

[0010] In some such examples, the modification step alternatively or additionally comprises sputtering and modifying the composition of the silicon- containing film.

[0011] In some such examples, modifying the composition of the silicon- containing film comprises nitridating the silicon-containing film.

[0012] In some such examples, the CVD step comprises forming a silicon oxide, a silicon oxynitride, or a silicon nitride film using a silane-based precursor, and wherein modifying the composition of the silicon-containing film by nitridating the silicon-containing film comprises nitridating the silicon oxide, the silicon oxynitride, or the silicon nitride film.

[0013] In some such examples, the method alternatively or additionally comprises performing a CVD cycle that omits the modification step.

[0014] Another example provides a method of performing plasma-enhanced CVD. The method comprises performing a plurality of CVD cycles. A CVD cycle of the plurality of CVD cycles comprises performing a CVD step by introducing a flow of tetraethylorthosilicate (TEOS) into a plasma to deposit a silicon oxide film onto a substrate. The CVD cycle further comprises, after performing the CVD step,performing a nitridation step by exposing the substrate to a plasma comprising a nitrogen source to nitridate the silicon oxide film, thereby forming a silicon oxynitride film.

[0015] In some such examples, the nitrogen source comprises one or more of nitrogen, ammonia, hydrazine, or a CN-containing species.

[0016] In some such examples, the plasma comprising the nitrogen source alternatively or additionally is formed using radiofrequency power comprising a low frequency energy component of 3 MHz or lower and a high frequency energy component of 3 MHz to 300 MHz.

[0017] In some such examples, the silicon oxide or silicon oxynitride film alternatively or additionally comprises a percentage of nitrogen that is up to 30% by atomic percentage.

[0018] In some such examples, exposing the substrate to the plasma alternatively or additionally comprises sputtering a reentrant structure of the silicon oxide film.

[0019] Another example provides a CVD tool. The CVD tool comprises a processing chamber. The CVD tool further comprises a substrate support disposed in the processing chamber. The CVD tool further comprises flow control hardware configured to control gas flows from one or more gas sources into the processing chamber. The CVD tool further comprises a controller. The controller is configured to perform a plurality of CVD cycles, each CVD cycle of the plurality of CVD cycles comprising a CVD step and a modification step. The controller is configured to, in each CVD step, operate the flow control hardware to introduce a silicon-containing precursor from a silicon-containing precursor source into the processing chamber to expose a substrate to the silicon-containing precursor under conditions configured to convert the silicon-containing precursor into a silicon-containing film on the substrate. The controller is further configured to, in each modification step, operate the flow control hardware and a radiofrequency power source to form a plasma to impinge ions on the surface of the silicon-containing film to at least modify a profile of the silicon- containing film or modify a composition of the silicon-containing film.

[0020] In some such examples, the controller is configured to operate the flow control hardware and the radiofrequency power source to form the plasma using an inert gas to change a profile of a reentrant portion of the silicon-containing by sputtering.

[0021] In some such examples, the CVD tool alternatively or additionally comprises the silicon-containing precursor source, the silicon-containing precursor source comprises TEOS or silane, and the controller is further configured to, in the modification step, operate the flow control hardware and the radiofrequency power source to modify the deposited silicon-containing film using one or more of argon, helium, nitrous oxide, ammonia, oxygen, or molecular nitrogen.

[0022] In some such examples, the CVD tool alternatively or additionally comprises the silicon-containing precursor source, the silicon-containing precursor source comprises silane, and the controller is further configured to, in the modification step, operate the flow control hardware and the radiofrequency power source to modify the deposited silicon-containing film using one or more of argon, helium, nitrous oxide, ammonia or molecular nitrogen.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1 A-1D schematically show structures formed on a substrate in an example chemical vapor deposition (CVD) process that results in void formation.

[0024] FIG. 2 shows a flow diagram of an example CVD process that includes a modification step to sculpt and / or modify a composition of a film.

[0025] FIG. 3 shows a flow diagram of an example CVD process that includes modifying a composition of a deposited film.

[0026] FIG. 4 shows a flow diagram of an example CVD process that includes sculpting a deposited film layer by sputtering.

[0027] FIGS. 5A-5G show example structures formed using the CVD process of FIG. 2 to perform gapfill while avoiding void formation.

[0028] FIGS. 6A-6E show example structures formed using the CVD process of FIG. 3 to deposit a silicon oxynitride film using tetraethylorthosilicate (TEOS) as a precursor.

[0029] FIGS. 7A-7F show example structures formed using the CVD process of FIG. 4 to perform silicon oxynitride gapfill using TEOS while avoiding void formation.

[0030] FIG. 8 shows a flow diagram of an example method for chemical vapor deposition with a plasma-based modification step.

[0031] FIG. 9 schematically shows an example CVD tool.

[0032] FIG. 10 shows a schematic diagram of an example computing system.DETAILED DESCRIPTION

[0033] The term “aspect ratio” generally represents a ratio between a depth of a feature and an average width of the feature.

[0034] The term “chemical vapor deposition” (CVD) generally represents a process in which a solid phase film is formed on a substrate by directing a continuous flow of one or more precursor gases over the substrate surface under conditions configured to cause the chemical conversion of the precursor gases to the film. The term “plasma-enhanced chemical-vapor deposition” (PECVD) generally represents a CVD process in which a plasma is used to facilitate the chemical conversion of one or more precursor gases to a solid phase film on a substrate. Thermal CVD (TCVD) processes utilize thermal energy to facilitate film formation. The terms “growth”, “deposition”, and variants thereof, also can be used to refer to film formation.

[0035] The term “CVD tool” generally represents a machine comprising a processing chamber and other hardware configured to perform CVD processing.

[0036] The term “CVD cycle” generally represents a multi-step process that can be repeated to form a film. A CVD cycle comprises a CVD step to deposit a film and a modification step to modify the deposited film.

[0037] The term “CVD step” generally represents deposition of a layer of a film in a CVD cycle.

[0038] The term “flow control hardware” generally represents components configured to place one or more chemical sources in fluid connection with a processing chamber. Flow control hardware may comprise one or more mass flow controllers and / or valves, for example. Example chemical sources include film precursor sources, inert gas sources, and reactant gas sources such as nitrogen sources and oxidant sources.

[0039] The term “gap” generally represents a recessed structure on a substrate.

[0040] The term “modification step” generally represents processes in a CVD cycle to perform at least physical modification or chemical modification of a deposited film.

[0041] The term “plasma” generally represents a gas comprising cations and free electrons.

[0042] The term “processing chamber” generally represents an enclosure in which chemical and / or physical processes are performed on substrates. The pressure,temperature and atmospheric composition within a processing chamber are controllable to perform chemical and / or physical processes.

[0043] The term “showerhead” generally represents a processing chemical outlet comprising a plurality of holes distributed across an area.

[0044] The term “silicon-containing precursor” generally represents any compound that can be introduced into a processing chamber in a gas phase to form a silicon-containing film on the substrate. Example silicon-containing films include silicon oxide (SiCh), silicon nitride (SisN4), silicon oxynitride (SiOxNy, 0 < x < 2, 0 < y< 1.33, hereinafter SiON), silicon carbide (SiC), silicon oxycarbide (SiCxO2(i-x), 0 < x< 1), silicon carbonitride (xSisN4 • (l-x)SiC), and silicon oxycarbonitride (SiOxCyNz, 0< x < 2, 0 < y < 1, 0 < z < 1.33). Example silicon-containing precursors for forming silicon-containing films using CVD can comprise materials having the general structure:where Ri, R2 and R3 can be the same or different substituents. In various examples, Ri, R2, and R3 can include silanes, siloxy groups, amines, halides, hydrogen, or organic groups such as alkylamines, alkoxy, alkyl, alkenyl, alkynyl, and cyclic groups (such as aromatic groups).

[0045] Example silicon-containing precursors include silane and polysilanes (H3Si-(SiH2)n-SiH3), where n > 0, such as disilane, trisilane, and tetrasilane, and trisilylamine. Silane and polysilanes are referred to herein as silanes or silane-based precursors. Silane-based precursors can include partially and substituted variants of silane and polysilanes.

[0046] In some examples, the silicon-containing precursor is an alkoxysilane. Alkoxysilanes that can be used include compounds having a general formula of Hx-Si- (OR)y, where x = 1-3, x+y = 4 and each R is a substituted or unsubstituted aliphatic or aromatic group; and Hx(RO)y,-Si-Si-(OR)yHx, where each R is a substituted or unsubstituted aliphatic or aromatic group. Example alkoxysilanes includetetramethoxysilane (TMOS), diethoxymethylsilane (DEMS), diethoxysilane (DES), dimethoxymethylsilane, dimethoxysilane (DMOS), methyl-diethoxysilane (MDES), methyl-dimethoxysilane (MDMS), t-butoxydisilane, triethoxysilane (TES), and trimethoxysilane (TMS or TriMOS).

[0047] In some examples, the silicon-containing precursor is a siloxane. Siloxanes include materials having Si-O-Si linkages. Example siloxanes include octamethylcyclotetrasiloxane (OMCTS), octamethoxydodecasiloxane (OMODDS), and tetramethylcyclotetrasiloxane (TMCTS).

[0048] In some examples, the silicon-containing precursor is an aminosilane. Aminosilanes include materials having a general formula Hx-Si-(NR)y, where x = 1-3, x+y = 4, and R is a substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aromatic group, or hydride group. Example aminosilanes include bisdiethylaminosilane, diisopropylaminosilane, bis(t-butylamino) silane (BTBAS), di-sec-butylaminosilane, and tris(dimethylamino)silane (3DMAS).

[0049] In some examples, the silicon-containing precursor is a halogencontaining silane or halogen-containing polysilane. Halogen-containing silanes and halogen-containing polysilanes are examples of silane-based precursors. In some examples, a halogen-containing silane can comprise at least one hydrogen atom. Such a silane can have a general formula of SiXaHy where y > 1. Example halosilanes include dichlorosilane (H2SiCh), hexachlorodisilane (Si2Cle), and diiodosilane (H2SH2).

[0050] More specific examples of silicon-containing precursors include tetraethylorthosilicate (TEOS), methylsilane, trimethylsilane (3MS), ethylsilane, butasilanes, pentasilanes, octasilanes, heptasilane, hexasilane, cyclobutasilane, cycloheptasilane, cyclohexasilane, cyclooctasilane, cyclopentasilane, 1,4-dioxa- 2,3,5,6-tetrasilacyclohexane, triethoxysiloxane (TRIES), and tetraoxymethylcyclotetrasiloxane (TOMCTS).

[0051] In some examples, an oxidant is used to react with the silicon-containing precursor. Examples include molecular oxygen (O2), nitrous oxide (N2O), water (H2O), hydrogen peroxide (H2O2), and carbon dioxide (CO2).

[0052] An example precursor for providing nitrogen for formation of a silicon oxynitride film is nitrous oxide (N2O).

[0053] The term “sputtering” and variants thereof generally represent processes in which ions in a plasma are accelerated toward a substrate with sufficient kinetic energy to cause at least some material on the substrate to be ejected from the substrate upon collision with the substrate.

[0054] The term “sticking coefficient” generally represents a ratio of a number of gas-phase species that adsorb to a substrate surface compared to a number of the gasphase species that impinge upon the substrate surface.

[0055] The term “substrate” generally represents any object on which a film can be deposited.

[0056] The term “substrate support” generally represents any structure for supporting a substrate in a processing chamber.

[0057] As mentioned above, chemical vapor deposition (CVD) uses a continuous flow of precursor compound(s) to deposit a film on a substrate. Plasma- enhanced CVD (PECVD) utilizes a plasma to facilitate chemical conversion of precursor compound(s) to form a film on the substrate. Thermal CVD (TCVD) processes utilize thermal energy to facilitate film formation.

[0058] Semiconductor device fabrication can involve etching gaps into a substrate. Gaps can be filled with another material in a process known as gapfill. PECVD is often used to fill a gap with a dielectric material, such as silicon oxide. However, reentrant structures can form during PECVD gapfill. Reentrancy narrows the opening of the gap. This can make gapfill more difficult, as precursor gases do not enter a narrow gap as easily as a wider gap. Eventually, the gap can seal off at the reentrancy, forming a void.

[0059] FIGS. 1A-1D schematically show structures in an example PECVD gapfill process that leads to void formation. FIG. 1 A shows a substrate 100 comprising a gap 102. Substrate 100 can comprise any suitable material. FIG. IB shows a silicon oxide film 104 deposited onto substrate 100, including within gap 102, by PECVD. PECVD can deposit more silicon oxide on the upper region of a sidewall of a gap (closer to a gap opening) than on a lower region of the sidewall within a gap (farther within the gap). This is because sticking coefficients of precursors for silicon oxide, such as tetraethylorthosilicate (TEOS) or silane-based precursors, can favor top heavy deposition. As a result, the silicon oxide film grows more rapidly on the upper region of the sidewall of the gap than on the lower region of the sidewall of the gap. As shown in FIG. IB, this can cause a silicon oxide film 104 to grow thicker on upper regions 106of gap 102 than on lower sidewalls 108. This can close the gap prior to filling the gap. While silicon film 104 comprises a silicon oxide film in this example, other films similarly can deposit in a top heavy manner in a PECVD process. Examples of other silicon-containing films include silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride.

[0060] FIG. 1C shows silicon oxide film 104 after further growth. Due to faster growth rate on upper sidewalls, reentrant structures 110 form on silicon oxide film 104. Reentrant structures 110 narrow the opening of gap 102. The narrower opening of the gap can make filling the gap more difficult. FIG. ID shows substrate 100 following further growth of silicon oxide film 104. Due to the reentrant structures 110, gap 102 closes before being completely filled. This forms a void 112. As shown in FIG. ID, the top of void 112 is above the top surface 114 of substrate 100. As such, etching silicon oxide film 104 to expose substrate 100 will open the void 112. This can cause issues in later fabrication steps. Void formation can be particularly problematic for smaller features and higher aspect ratio features, such as features with aspect ratios of 0.5: 1 or greater.

[0061] Atomic layer deposition (ALD) is one possible method to avoid forming voids in a gapfill process. ALD involves forming a film on a substrate in one or more individual layers by sequentially adsorbing precursor to the substrate and then chemically converting the adsorbed precursor to the desired film in self-limiting steps. In this manner, ALD can be used to deposit a conformal film in a layer-by-layer process, thereby avoiding void formation. However, ALD can be higher cost and slower than CVD. Another gapfill methods is spin-on deposition (SOD) of a liquid phase precursor solution. However, SOD can produce films that are lower quality than PECVD films. For example, SOD films can be less thermally stable and more prone to cracking than PECVD films.

[0062] Accordingly, examples are disclosed that relate to cyclic CVD processes that can address such issues with current CVD processes. Briefly, a CVD process comprises a plurality of deposition cycles. Each deposition cycle comprises a deposition step that uses CVD to deposit a silicon-containing film. After performing the deposition step, the deposition cycle comprises a plasma-based modification step. The plasma-based modification step comprises at least physical modification or chemical modification of a deposited film. In some examples, the modification step comprises at least forming a plasma to sculpt the silicon-containing film by sputtering.In other examples, the modification step comprises at least forming a plasma to modify a composition of the silicon-containing film. In yet further examples, the modification step comprises both sculpting and composition modification.

[0063] Sputtering can be used in a modification step, for example, to sculpt the film to remove reentrant structures in gaps. This widens the opening of the gap. Widening the opening of the gap allows the deposition process to fill the interior of the gap. Example deposition steps and modification steps are described in more detail below. By sculpting the CVD film to remove reentrant structures, the deposition cycles can be repeated to fill the gap without pinching off the opening of the gap. As such, the disclosed examples can provide for void-free gapfill using CVD that is not limited to low aspect ratios, such as aspect ratios less than 0.5: 1. This can provide cost and / or time savings compared to other gapfill processes, such as ALD. Further, gapfill can be performed using PECVD to deposit a film that is less prone to cracking and more thermally stable than films grown by SOD.

[0064] Various processing conditions can be adjusted to control the degree of sputtering in a modification step of a deposition cycle. As one example, the modification step can be performed using a plasma with both a higher frequency radiofrequency energy component (“HF component”) and a lower frequency radiofrequency energy component (“LF component”). The HF component can comprise frequencies of 3 MHz and higher (e.g. 3 MHz to 300 MHz). Examples include 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. The LF component can comprise frequencies of 3 MHz and lower. Examples include 2 MHz and 400 kHz. Use of the LF component of radiofrequency energy in addition to a HF component of radiofrequency energy can provide a greater sputtering rate than examples that omit the LF component of radiofrequency energy. As another example, increasing the power of the HF component can help increase the concentration of inert gas ions in the plasma to increase the sputtering rate. As a further example, increasing the power of the LF component can increase the kinetic energy of inert gas ions in the plasma to help increase the sputtering rate. As yet another example, use of a relatively lower pressure can provide a greater sputtering rate the use of a relatively higher pressure due to lower pressures providing for longer mean free paths of ions in the plasma.

[0065] As mentioned above, various silicon-containing precursors can be used in a CVD process to deposit a silicon-containing film. Example silicon-containing films include silicon oxide (SiCh) films and silicon oxynitride (SiON) films. These materialsare often used as dielectric films in integrated circuits. One example of a silicon- containing film precursor is tetraethylorthosilicate (TEOS, Si(OC2Hs)4). The central Si atom in the TEOS molecule is bonded to four oxygen atoms. TEOS reacts with molecular oxygen (O2) in a plasma environment to form high quality silicon oxide films. TEOS can be used to deposit films with good conformality and low carbon content. Further, TEOS is a relatively low-cost precursor. As such, TEOS is often used in CVD for silicon oxide deposition. However, deposition of other films, such as silicon oxynitride, using TEOS can be challenging. For example, performing CVD with TEOS and a nitrogen-containing precursor does not form silicon oxynitride to any significant extent. This is because the Si-0 bond is thermodynamically favored over a Si-N bond. As such, CVD processes for depositing silicon oxynitride films by CVD use other precursors, such as a mixture of silane (SiH4), ammonia (NH3), and nitrous oxide (N2O).

[0066] Accordingly, examples are also disclosed that relate to forming a silicon oxynitride film using TEOS as a precursor in a cyclic CVD process. Briefly, TEOS is used in a deposition step of a CVD cycle to deposit a layer of a silicon oxide film. Then, in a modification step, a plasma is formed using a nitrogen source, such as ammonia, molecular nitrogen (N2), hydrazine (N2H4), and / or a CN-containing species (e.g. hydrogen cyanide (HCN) or a suitable nitrile). Energetic nitrogen ions formed in the plasma impinge on the layer of silicon oxide film to break Si-0 bonds and form Si-N bonds. This forms a layer of silicon oxynitride. The deposition cycles are repeated to sequentially deposit and nitridate additional layers of silicon oxide, thereby forming a silicon oxynitride film. As such, the CVD process allows formation of a silicon oxynitride film using TEOS as a precursor. As mentioned above, TEOS is relatively low cost and can produce high quality silicon oxide films. As such, the disclosed examples can provide cost savings compared to other silicon oxynitride deposition methods. Further, various conditions of the modification step can be controlled to adjust the nitrogen concentration in the silicon oxynitride film. For example, a relatively longer nitridation step can be used to increase the nitrogen concentration in the silicon oxynitride film compared to a relatively shorter nitridation steps. The disclosed examples can be implemented into processing tools that are configured for performing CVD using TEOS.

[0067] In some examples, the modification step of the deposition cycle can comprise both physical modification by sputtering and chemical modification by nitridation. This can be used to deposit silicon oxynitride in a CVD gapfill process thatuses TEOS. In such examples, TEOS is used as a precursor in the deposition step to deposit a silicon oxide film in a gap on a substrate. Then, the modification step comprises forming a plasma using a gas mixture comprising a nitrogen source, such as molecular nitrogen, ammonia, hydrazine, or a CN-containing species, such as hydrogen cyanide. Further, the modification step is performed using plasma conditions configured to sputter the deposited silicon-containing film. In this manner, the modification step preferentially sputters reentrant structures in the gap and nitridates the silicon-oxide film, thereby forming a layer silicon oxynitride film in the gap. The deposition step and modification step can be repeated in any suitable number of deposition cycles to fill the gap with silicon oxynitride without void formation. Example deposition cycles are described in more detail below. It will be understood that SiON films formed in other manners than nitridation of a TEOS-deposited oxide also can be sculpted by sputtering. For example, silane, ammonia, and nitrous oxide can be used as precursors to deposit a silicon oxynitride film using PECVD. Other silane- based precursors and / or other nitrogen-containing precursors also can be used. After depositing the silicon oxynitride film, the film can be sculpted by performing a modification step. The modification step comprises forming a plasma to sputter the silicon oxynitride film. Then, one or more additional CVD cycles can be performed. In this manner, a silicon oxynitride gapfill can be performed using a silane-based precursor without forming a void.

[0068] FIGS. 2-4 show flow diagrams illustrating example methods for depositing films using cyclic CVD processes. FIG. 2 illustrates a method 200 in which a modification step of a cyclic CVD process is used both to modify a composition of and a shape of a film layer. FIG. 3 illustrates a method in which a modification step of a cyclic CVD process is used to modify a composition of a film layer (in this example, by nitridation). FIG. 4 illustrates a method 400 in which a modification step of a cyclic CVD process is used to sculpt a film layer.

[0069] Referring first to FIG. 2, method 200 comprises performing a plurality of CVD cycles 202. CVD cycle 202 comprises performing a CVD step 204 and performing a modification step 210. As described below, the modification step 210 can be omitted from some CVD cycles in a CVD process.

[0070] CVD step 204 comprises exposing the substrate to a silicon-containing precursor under conditions configured to convert the silicon-containing precursor into a silicon-containing film. Example silicon-containing films include silicon oxide,silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxy carbonitride. Any suitable silicon-containing precursor can be used. In some examples, at 206, TEOS is introduced into a plasma to deposit silicon oxide by PECVD. As mentioned above, TEOS is relatively inexpensive and can form high-quality silicon oxide films using PECVD. In some examples, TEOS is deposited with an oxidant, such as nitrous oxide or molecular oxygen. Further, a layer of silicon oxide film deposited with TEOS precursor can be modified by nitridation, as described below. Another example of a silicon-containing precursor is silane.

[0071] Further examples of silicon-containing precursors for forming silicon- containing films using CVD can comprise materials having the general structure:where Ri, R2 and R3 can be the same or different substituents. In various examples, Ri, R2, and R3 can include silanes, siloxy groups, amines, halides, hydrogen, or organic groups such as alkylamines, alkoxy, alkyl, alkenyl, alkynyl, and cyclic groups (such as aromatic groups).

[0072] In some examples, the silicon-containing precursor is an alkoxysilane. Alkoxysilanes that can be used include compounds having a general formula of Hx-Si- (OR)y, where x = 1-3, x+y = 4 and each R is a substituted or unsubstituted aliphatic or aromatic group; and Hx(RO)y,-Si-Si-(OR)yHx, where each R is a substituted or unsubstituted aliphatic or aromatic group. Example alkoxysilanes include tetramethoxysilane (TMOS), diethoxymethylsilane (DEMS), diethoxysilane (DES), dimethoxymethylsilane, dimethoxysilane (DMOS), methyl-diethoxysilane (MDES), methyl-dimethoxysilane (MDMS), t-butoxydisilane, triethoxysilane (TES), and trimethoxysilane (TMS or TriMOS).

[0073] In some examples, the silicon-containing precursor is a siloxane. Siloxanes include materials having Si-O-Si linkages. Example siloxanes include octamethylcyclotetrasiloxane (OMCTS), octamethoxydodecasiloxane (OMODDS), and tetramethylcyclotetrasiloxane (TMCTS).

[0074] In some examples, the silicon-containing precursor is an aminosilane. Aminosilanes include materials having a general formula Hx-Si-(NR)y, where x = 1-3,x+y = 4, and R is a substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aromatic group, or hydride group. Example aminosilanes include bisdiethylaminosilane, diisopropylaminosilane, bis(t-butylamino) silane (BTBAS), di-sec-butylaminosilane, and tris(dimethylamino)silane (3DMAS).

[0075] In some examples, the silicon-containing precursor is a silane- containing precursor. In some such examples, the silane-containing precursor is partially or fully halogen-substituted. Such a silane can have a general formula of SiXaHy where y > 0. Example halosilanes include dichlorosilane (EESiCh), hexachlorodisilane (Si2Cle), and diiodosilane (H2SH2).

[0076] More specific examples of silicon-containing precursors include silane, polysilanes (SinH2n+2, where n >1, such as disilane, trisilane, and tetrasilane), trisilylamine, methylsilane, trimethylsilane (3MS), ethylsilane, butasilanes, pentasilanes, octasilanes, heptasilane, hexasilane, cyclobutasilane, cycloheptasilane, cyclohexasilane, cyclooctasilane, cyclopentasilane, 1, 4-dioxa-2, 3,5,6- tetrasilacyclohexane, triethoxysiloxane (TRIES), and tetraoxymethylcyclotetrasiloxane (TOMCTS).

[0077] As mentioned above in the example of TEOS, an oxidant can be used to react with the silicon-containing precursor in a CVD process. Examples include molecular oxygen, nitrous oxide, water, hydrogen peroxide, and carbon dioxide. An example precursor for providing nitrogen for formation of a silicon oxynitride film is nitrous oxide. Further, when using TEOS, a silicon oxynitride film can be formed by performing a modification step including nitridation, according to the examples described herein.

[0078] As mentioned above, in some examples, a silicon-containing film includes carbon. Examples of such silicon-containing films include silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride. Examples of carbon-containing precursors for forming such films include alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alkyl halides, alkyl amines, and alkyl diamines. More specific examples include acetylene and propylene.

[0079] In some examples, thermal CVD can be used as CVD step 204. In such examples, CVD step 204 comprises heating the substrate to convert the silicon- containing precursor into the silicon-containing film. Examples of temperatures forthermal CVD processes include temperatures of 500 °C to 1200 °C. In other examples, temperatures outside this range can be used.

[0080] In other examples, PECVD can be used as the CVD step 204. In such an example, a plasma is formed to facilitate chemical conversion of the silicon-containing precursor into the silicon-containing film (i.e., a PECVD process). For example, TEOS can be introduced to the plasma at 206. Example plasma conditions include radiofrequency power of 50 to 6000 Watts (W). Example frequencies for the radiofrequency plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma can comprise a HF component of radiofrequency energy and a LF component of radiofrequency energy. The HF component can comprise frequencies of 3 MHz to 300 MHz. The LF component can comprise frequencies of 3 MHz and below. The HF component can comprise a radiofrequency power of 50 to 6000 W. The LF component can comprise a radiofrequency power of 0 to 3000 W.

[0081] In some examples, use of relatively lower power radiofrequency energy can help deposit a relatively low density silicon-containing film. A relatively lower density silicon-containing film can be more susceptible to nitridation or other composition modification than a relatively higher density silicon-containing film. Further, a relatively lower density silicon-containing film can be more easily sculpted by sputtering than a relatively higher density film than a relatively higher density silicon-containing film. Thus, in some examples, the CVD step comprises forming a plasma using a radiofrequency power of 50 to 4000 W. In some more specific examples, a radiofrequency power of 100 to 1000 W can be used. Further, CVD step 204 can be performed at any suitable pressure. Examples include pressures of 0.5 Torr to 20 Torr.

[0082] CVD step 204 can be performed for any suitable duration. In some examples, CVD step 204 is performed to deposit a layer of silicon-containing film comprising a thickness of 1 to 10 nm. In more specific examples, the layer of silicon- containing film can comprise a thickness of approximately 3 nm. In other examples, each layer of film can comprise any other suitable thickness.

[0083] After performing the CVD step 204, method 200 comprises, at 208, determining whether to perform a modification step. If a modification step is to be performed, method 200 proceeds to 210 to perform the modification step. Otherwise, modification step 210 can be omitted for a selected CVD cycle.

[0084] Modification step 210 comprises using a plasma to impinge ions on the silicon-containing film. Modification step 210 comprises at least physical modification or chemical modification of the silicon-containing film. As shown at 212, impinging ions on the silicon-containing film can be used to modify the profile of the silicon- containing film. Further, as shown at 214, impinging ions on the silicon-containing film can be used to modify the composition of the silicon-containing film. An example process including step 212 is schematically shown in FIGS. 5A-5G. An example process including step 214 is schematically shown in FIGS. 6A-6E. Further, an example process that includes both step 212 and step 214 is schematically shown in FIGS. 7A- 7F. These examples are described in detail below.

[0085] Modifying the profile of the film at 212 comprises forming a plasma using an inert gas to sputter at least a portion of the silicon-containing film. This reduces a reentrant structure of the silicon-containing film. Any suitable inert gas can be used. Examples include Ar, He, Ne, Kr, and Xe. Any suitable sputtering conditions can be used. Examples of suitable pressures include pressures of 0.5 Torr to 5 Torr. Examples of suitable temperatures include temperatures of 250 °C to 650 °C. In some examples, silicon-containing precursor is flowed through a showerhead into a processing chamber to react with a substrate on a substrate support. In some such examples, the substrate support is heated to first temperature and the showerhead can be heated to a second temperature. For example, the showerhead can be heated to a second temperature that is lower than the first temperature.

[0086] Any suitable plasma conditions can be used to sputter the film. Example frequencies for the radiofrequency plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF component and a LF component of radiofrequency energy. In more specific examples, the radiofrequency plasma can formed using a HF component of 27 MHz and a LF component of 400 kHz. Use of a LF component in addition to a HF component can provide a greater sputtering rate than examples that omit LF radiofrequency energy. In some examples, the HF component can comprise a radiofrequency power of 50 to 6000 W. Alternatively or additionally, in some examples, the LF component can comprise a radiofrequency power of 0 to 3000 W. Increasing the power of the HF component can help increase the concentration of inert gas ions in the plasma to increase the sputtering rate. Further, increasing the power of the LF component can increase the kinetic energy of inert gas ions in the plasma to help increase the sputtering rate.

[0087] Continuing, in some examples, at 214, method 200 modifying the composition of the silicon oxide film. In some such examples, the modification step modifies the silicon oxide film by exposing the silicon oxide film to a plasma comprising nitrogen, at 216. This nitridates the silicon oxide film to form a silicon oxynitride film. In some examples, the modification step modifies a deposited silicon- containing film by exposing the silicon-containing film to a plasma comprising one or more of nitrous oxide, ammonia, oxygen, or molecular nitrogen.

[0088] Nitridating the silicon-containing film at 214 comprises using a plasma to impinge nitrogen ions on the film. As such, at 216, method 200 comprises exposing the silicon oxide film to a plasma comprising a nitrogen source, such as molecular nitrogen, ammonia, hydrazine, a material comprising a -CN group (e.g. hydrogen cyanide), or a combination thereof. Nitrogen ions in the plasma impinge on the silicon- containing film to implant nitrogen into the film. Example frequencies for the plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF component and a LF component of radiofrequency energy. Further, in some examples, the HF component can comprise a radiofrequency power of 50 to 6000 W. Alternatively or additionally, the LF component can comprise a radiofrequency power of 0 to 3000 W.

[0089] In some examples, processing conditions of the modification step can be adjusted to control the chemical species (e.g. nitrogen) concentration in a silicon oxynitride film. For example, increasing the power of the HF component can help increase the concentration of nitrogen ions or other ions in the plasma and increase the nitridation rate. Further, increasing the power of the LF component can increase the kinetic energy of nitrogen ions or other ions in the plasma to help break Si-0 bonds in a silicon oxide film. This can help increase the nitridation rate. In some more particular examples, the radiofrequency plasma is formed using a HF component of 27 or 13.56 MHz and a LF component of 400 kHz. Use of an LF component in addition to a HF component can provide a greater nitridation rate than examples that omit LF radiofrequency energy. Additionally, using a longer duration modification step can help increase nitridation.

[0090] As mentioned above, a relatively lower density silicon oxide film can be more susceptible to nitridation than a relatively higher density silicon oxide film. Thus, in some examples, the processing conditions in CVD step 204 can be controlled to produce a silicon oxide film having a relatively lower density than that produced byother conditions. For example, using relatively lower power radiofrequency energy of < 1500 W can form a silicon oxide film having a lower density than a film formed using radiofrequency energy having a relatively higher power of > 1500 W. This can help increase the nitrogen concentration in the silicon oxynitride film formed at step 214 relative to a higher density film under similar conditions. As such, the processing conditions of the modification step can be controlled to achieve a desired nitrogen concentration. In some examples, the nitrogen concentration in the silicon oxynitride film is up to 30% by atomic percentage. In other examples, a silicon oxynitride film can be formed with any other suitable nitrogen concentration.

[0091] Chemical modification of a relatively thicker layer of silicon oxide film can be more difficult than nitridation of a relatively thinner layer of silicon oxide film. For example, it might be difficult to implant nitrogen or other ions deeper into a layer of a silicon-containing film than a few nanometers. As such, depositing a relatively thinner layer of silicon oxide at CVD step 204 can help provide a more consistent nitrogen (or other species) concentration in the modified oxide film following step 214. Thus, in some examples, step 214 comprises modifying the composition of a layer silicon oxide film comprising a thickness of approximately 3 nm (e.g., 1 nm to 5 nm).

[0092] Continuing, at 220, method 200 comprises determining whether to perform additional CVD cycles 202. If additional CVD cycles are to be performed, method 200 returns to 202 and performs another CVD cycle. Any suitable number of CVD cycles 202 can be performed during processing of a substrate. On the other hand, if it is determined at 220 not to perform additional CVD cycles, the method 200 terminates at 224.

[0093] In some examples, processing conditions can be changed between CVD cycle of a film deposition process according to the present disclosure. For example, the amount of sputtering to remove reentrant structures can change as a gap is filled. Thus, in some examples, a duration of a modification step of a later CVD cycle can be different from a duration of a modification step of an earlier CVD cycle. In other examples, processing conditions can remain consistent between CVD cycles.

[0094] FIG. 3 shows a flow diagram illustrating an example method 300 for depositing a film on a substrate using a cyclic CVD process that includes composition modification (nitridation in this example).

[0095] CVD step 304 comprises exposing the substrate to a silicon-containing precursor under conditions configured to convert the silicon-containing precursor into a silicon oxide film. In other examples, a different silicon-containing film can be used. Any suitable silicon-containing precursor can be used. In some examples, at 306, the method 300 comprises introducing TEOS into the plasma. As mentioned above, TEOS is relatively inexpensive and can form high-quality silicon oxide films using PECVD. In some examples, TEOS is deposited with an oxidant, such as nitrous oxide or molecular oxygen. Further, a layer of silicon oxide film deposited with TEOS precursor can be modified by nitridation, as described below. In other examples, a silane-based precursor can be used to deposit a silicon-containing film. In some such examples, the silicon-containing film can comprise silicon oxide, silicon oxynitride, or silicon nitride Further examples of silicon-containing precursors include those listed above.

[0096] In some examples, thermal CVD can be used as the CVD step 304. In other examples, PECVD can be used. Examples of plasma conditions are described above. In some examples, use of relatively lower power radiofrequency energy can help deposit a relatively low density silicon-containing film. A relatively lower density silicon-containing film can be more susceptible to nitridation than a relatively higher density silicon-containing film.

[0097] After performing the CVD step 304, method 300 comprises, at 308, determining whether to perform a modification step. If a modification step is to be performed, method 300 proceeds to 310 to perform the modification step. Otherwise, modification step 310 can be omitted for a selected CVD cycle.

[0098] Modification step 310 comprises modifying the composition of the film by nitridating the film. In some examples, modification step 310 comprises nitridating a silicon oxide film, such as a film formed by TEOS or a silane-based precursor. In other examples, a silicon nitride or silicon oxynitride film formed from a silane-based precursor can be further nitridated. In yet further examples, any other suitable silicon- containing film can be nitridated.

[0099] The modification step 310 comprises forming a plasma comprising a nitrogen source, such as molecular nitrogen, ammonia, hydrazine, a CN-containing species (e.g. hydrogen cyanide), or a combination of two or more thereof. Nitrogen ions in the plasma impinge on the silicon-containing film to implant nitrogen into the film. Example frequencies for the plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HFcomponent and a LF component of radiofrequency energy. Further, in some examples, the HF component can comprise a radiofrequency power of 50 to 6000 W. Alternatively or additionally, the LF component can comprise a radiofrequency power of 0 to 3000 W.

[0100] In some examples, processing conditions of the modification step can be adjusted to control the nitrogen concentration in a silicon oxynitride film. For example, increasing the power of the HF component can help increase the concentration of nitrogen ions in the plasma and increase the nitridation rate. Further, increasing the power of the LF component can increase the kinetic energy of nitrogen gas ions in the plasma to help break Si-0 bonds in a silicon oxide film. This can help increase the nitridation rate. In some more particular examples, the radiofrequency plasma is formed using a HF component of 27 or 13.56 MHz and a LF component of 400 kHz. Use of an LF component in addition to a HF component can provide a greater nitridation rate than examples that omit LF radiofrequency energy. Additionally, using a longer duration modification step can help increase nitridation.

[0101] As mentioned above, a relatively lower density silicon oxide film can be more susceptible to nitridation than a relatively higher density silicon oxide film. Thus, in some examples, the processing conditions in CVD step 304 can be controlled to produce a silicon oxide film having a relatively lower density than that produced by other conditions. For example, using relatively lower power radiofrequency energy of < 1500 W can form a silicon oxide film having a lower density than a film formed using radiofrequency energy having a relatively higher power of > 1500 W. This can help increase the nitrogen concentration in the silicon oxynitride film formed at step 310 relative to a higher density film under similar conditions. As such, the processing conditions of the modification step can be controlled to achieve a desired nitrogen concentration. In some examples, the nitrogen concentration in the silicon oxynitride film is up to 30% by atomic percentage. In other examples, a silicon oxynitride film can be formed with any other suitable nitrogen concentration.

[0102] Continuing, at 320, method 300 comprises determining whether to perform additional CVD cycles 302. If additional CVD cycles are to be performed, method 300 returns to 302 and performs another CVD cycle. Any suitable number of CVD cycles 302 can be performed during processing of a substrate. On the other hand,if it is determined at 320 not to perform additional CVD cycles, the method 300 terminates at 324.

[0103] FIG. 4 shows a flow diagram illustrating an example method 400 for depositing a film on a substrate using a cyclic CVD process that includes sputtering.

[0104] CVD step 404 comprises exposing the substrate to a silicon-containing precursor under conditions configured to convert the silicon-containing precursor into a silicon-containing film. Example silicon-containing films include silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxy carbonitride. Any suitable silicon-containing precursor can be used. In some examples, at 406, the CVD step 404 comprises using a silane-based precursor to deposit the silicon-containing film. In some such examples, the silicon- containing film comprises silicon oxide, silicon oxynitride, or silicon nitride. Examples of silane-based precursors include partially and substituted variants of silane and poly silanes. For example, silane, ammonia, and nitrous oxide can be used as precursors to deposit a silicon oxynitride film. Further examples of silicon-containing precursors for forming silicon-containing films include those listed above.

[0105] In some examples, thermal CVD can be used as the CVD step 404. In other examples, PECVD can be used. For example, the silane-based precursor introduced at 406 can be introduced into a plasma. Examples of plasma conditions are described above. In some examples, use of relatively lower power radiofrequency energy can help deposit a relatively low density silicon-containing film. A relatively lower density silicon-containing film can be more susceptible to sputtering than a relatively higher density silicon-containing film.

[0106] After performing the CVD step 404, method 400 comprises, at 408, determining whether to perform a modification step. If a modification step is to be performed, method 400 proceeds to 410 to perform the modification step. Otherwise, modification step 410 can be omitted for a selected CVD cycle.

[0107] Modification step 410 comprises forming a plasma using an inert gas to sputter at least a portion of the silicon-containing film. This reduces a reentrant structure of the silicon-containing film. Any suitable inert gas can be used. Examples include Ar, He, Ne, Kr, and Xe. Any suitable sputtering conditions can be used. Examples of suitable pressures include pressures of 0.5 Torr to 5 Torr. Examples of suitable temperatures include temperatures of 250 °C to 650 °C. In some examples, silicon- containing precursor is flowed through a showerhead into a processing chamber to reactwith a substrate on a substrate support. In some such examples, the substrate support is heated to first temperature and the showerhead can be heated to a second temperature that is lower than the first temperature.

[0108] Any suitable plasma conditions can be used to sputter the film. Example frequencies for the radiofrequency plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF component and a LF component of radiofrequency energy. In more specific examples, the radiofrequency plasma can formed using a HF component of 27 MHz and a LF component of 400 kHz. Use of a LF component in addition to a HF component can provide a greater sputtering rate than examples that omit LF radiofrequency energy. In some examples, the HF component can comprise a radiofrequency power of 50 to 6000 W. Alternatively or additionally, in some examples, the LF component can comprise a radiofrequency power of 0 to 4000 W. Increasing the power of the HF component can help increase the concentration of inert gas ions in the plasma to increase the sputtering rate. Further, increasing the power of the LF component can increase the kinetic energy of inert gas ions in the plasma to help increase the sputtering rate. In some examples, at 412, modification step 410 comprises modifying the silicon-containing film deposited at CVD step 404. In this manner, method 400 can be used to deposit and sculpt a silicon oxynitride film.

[0109] Continuing, at 420, method 400 comprises determining whether to perform additional CVD cycles 402. If additional CVD cycles are to be performed, method 400 returns to 402 and performs another CVD cycle. Any suitable number of CVD cycles 402 can be performed during processing of a substrate. On the other hand, if it is determined at 420 not to perform additional CVD cycles, the method 400 terminates at 424.

[0110] FIGS. 5A-5G schematically show example structures formed during a cyclic CVD process that includes cycles of deposition steps and modification steps to avoid formation of a void. FIGS. 5A-5G illustrate an example of method 200 including step 212 or an example of method 400. First referring to FIG. 5A, substrate 500 comprises a gap 502. Substrate 500 can comprise any suitable material. Gap 502 comprises an aspect ratio of approximately 1 : 1. In other examples, the gap can comprise any other suitable aspect ratio. In some examples, the gap comprises an aspect ratio of up to 5 : 1. In some such examples, the gap comprises an aspect ratio of 0.5 : 1 or greater.

[0111] FIG. 5B shows substrate 500 following a CVD step, such as CVD step 204 or CVD step 404. During the CVD step, substrate 500 is exposed to a silicon- containing precursor under conditions configured to convert the silicon-containing precursor into a silicon-containing film 504. Example silicon-containing films include silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxy carbonitride. For example, a silicon oxy carbide film can be deposited using silane, carbon tetrafluoride, and nitrous oxide. As another example, silane, ammonia, and nitrous oxide can be used as precursors to deposit a silicon oxynitride film. In some examples, a plasma is used to form the silicon- containing film (i.e., PECVD).

[0112] Due to the sticking coefficient of the silicon-containing precursor within a plasma environment, top heavy deposition occurs. As a result, silicon-containing film 504 grows faster on upper sidewall surfaces 506 of gap 502 than deeper in the gap. This forms reentrant structures 508. The reentrant structures 508 narrow the opening of gap 502. This can make it more difficult for silicon-containing precursor to form film at the bottom of gap 502. Thus, a modification step is performed. FIG. 5C shows substrate 500 following a modification step, such as step 212 or step 410, to sculpt the profile of silicon-containing film 504 by sputtering. The modification step comprises forming a plasma comprising gas ions. In the example shown, argon ions 510 are used to sputter the silicon-containing film 504. In other examples, another suitable inert gas can be used. Further, in some examples, a nitrogen-containing gas can be used to both sculpt and nitridate the film, as described in more detail below. As a result of the modification step, reentrant structures 508 are removed and the profile of silicon-containing film 504 is sculpted to a V-shape.

[0113] Additional deposition cycles can be performed to continue filling gap 502 of substrate 500. FIG. 5D shows substrate 500 following a CVD step of a subsequent deposition cycle to deposit an additional layer of silicon-containing film 504 on the substrate. Again, film growth is faster on upper sidewalls 506 of gap 502. This forms reentrant structures 508. Continuing to FIG. 5E, the modification step of the subsequent deposition cycle modifies the profile of silicon-containing film 504 by sputtering with argon ions 510. This removes the reentrant structures 508 of FIG. 5D and modifies the profile of silicon-containing film 504 to a V-shape.

[0114] FIG. 5F shows substrate 500 following yet another deposition cycle to deposit and modify an additional layer of silicon-containing film 504 onto the substrate.Silicon-containing film 504 comprises a V-shaped profile that allows the gap to be filled prior to closing the gap. This helps avoid void formation. FIG. 5G shows substrate 500 following additional deposition cycles. Silicon-containing film 504 is deposited into gap 502 void-free. Thus, the use of deposition cycles comprising CVD steps and modification steps can be used for void-free gapfill.

[0115] FIGS. 6A-6E schematically show example structures formed during a CVD process that includes a modification step to modify the composition of a film. FIGS. 6A-6E illustrate an example of method 200 including step 214 or an example of method 300. First referring to FIG. 6A, substrate 600 comprises any suitable material onto which a silicon oxide film can be deposited. FIG. 6B shows substrate 600 following a CVD step, such as step 206 or step 306, in which TEOS 602 is introduced into a plasma. The CVD step also can comprise introducing an oxidant, such as nitrous oxide or molecular oxygen, to the plasma. This forms a layer of silicon oxide film 604. In some examples, the silicon oxide film 604 is deposited using PECVD with a radiofrequency power of 200 W to 3000 W. As mentioned above, use of relatively lower power radiofrequency energy (for example, less than or equal to 3000 W) can help deposit a silicon oxide film that is relatively low density compared to the use of a relatively higher power radiofrequency energy. A relatively lower density silicon oxide film can be more susceptible to nitridation than a relatively higher density silicon oxide film.

[0116] Next, a modification step is performed, such as step 214, step 216, or step 310. FIG. 6C shows substrate 600 following the modification step. The modification step comprises forming a plasma comprising a nitrogen source 606. In the depicted example, the nitrogen source comprises molecular nitrogen and ammonia. In other examples, either of nitrogen or ammonia can be omitted. In further examples, any other suitable nitrogen source, such as hydrazine or a CN-containing species (e.g. hydrogen cyanide), alternatively or additionally can be used. The plasma is used to impinge nitrogen ions on the layer of silicon oxide 604 to nitridate the layer of silicon oxide film 604. This forms a first layer of nitridated oxide 610A.

[0117] Any suitable plasma conditions can be used to form the first layer of nitridated oxide 610A. Examples include radiofrequency power of 50 to 6000 W and frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF component and a LF component of radiofrequency energy. Examples of HF radiofrequency energy include radiofrequency power of 50 to6000 W. Examples of LF radiofrequency energy include radiofrequency power of 0 to3000 W.

[0118] The first layer of nitridated oxide 610A comprises silicon oxynitride. As described above, nitrogen concentration can vary in silicon oxynitrides. In some examples, the nitrogen concentration in the silicon oxynitride film is up to 30% by atomic percentage. Further, the processing conditions of the modification step can be adjusted to control the nitrogen concentration in the first layer of nitridated oxide 610A. For example, using a higher power radiofrequency energy can help increase the concentration of nitrogen ions in the plasma and increase nitridation of the silicon oxide film. Additionally, using a longer duration modification step can help increase nitridation.

[0119] As mentioned above, a relatively lower density silicon oxide film can be more susceptible to nitridation than a relatively higher density silicon oxide film. Thus, in some examples, the silicon-oxide film is deposited in a CVD step that uses a radiofrequency power of 3000 W or lower. This helps deposit a silicon oxide film 604 comprising a relatively low density compared to a silicon oxide film deposited at a radiofrequency power of greater than 3000 W.

[0120] The deposition cycle shown in FIGS. 6B-6C can be repeated to form additional layers of silicon oxynitride. FIG. 6D shows substrate 600 following a CVD step of a subsequent deposition cycle. The CVD step comprises introducing TEOS 602 into a plasma to deposit a silicon oxide film 604 onto the first layer of nitridated oxide 610A. Next, a modification step is performed to convert the silicon oxide into silicon oxynitride. FIG. 6E shows the result of the modification step of the subsequent deposition cycle. The modification step comprises forming a plasma comprising a nitrogen source 606. Nitrogen ions in the plasma impinge on the layer of silicon oxide film 604 to nitridate the layer of silicon oxide film 604. This forms a second layer of nitridated oxide 610B on top of the first layer of nitridated oxide 610A. Additional deposition cycles can be performed to achieve any suitable film thickness. In this manner, a silicon oxynitride film can be deposited using a TEOS precursor.

[0121] FIGS. 7A-7F schematically show example structures formed during a CVD process that includes a modification step to modify both the profile and modify the composition of a film. FIGS. 7A-7F illustrate an example of method 200 including step 212 and step 214. First referring to FIG. 7A, substrate 500 comprises a gap 702.Substrate 700 can comprise any suitable material. FIG. 7B shows substrate 700 following a CVD step, such as CVD step 204 including step 206.

[0122] During the CVD step, substrate 700 is exposed to a plasma and TEOS 704 is introduced to the plasma to deposit a layer of silicon oxide film 706. In some examples, the silicon oxide film 706 is deposited in a PECVD step that uses a radiofrequency power to form a plasma. In some such examples, the plasma is formed using radiofrequency power of 200 W to 3000 W. As mentioned above, use of relatively low power radiofrequency energy < 3000 W can help deposit a silicon oxide film that is relatively low density and that is more susceptible to nitridation than the use of a radiofrequency power of greater than 3000 W. In other such examples, the plasma can have a radiofrequency power of greater than 1500 W.

[0123] TEOS 704 can favor top heavy deposition within gap 702 within a plasma environment. As a result, the layer of silicon oxide film 706 grows faster on upper sidewall surfaces 708 of gap 702 than deeper in gap 702. This forms reentrant structures 710 and narrows the opening of gap 702.

[0124] Thus, a modification step is performed next to sculpt the silicon oxide film 706 to reduce or remove reentrant structures 710. FIG. 7C shows substrate 700 following a modification step that includes steps 212 and 214 of method 200. The modification step comprises forming a plasma comprising a nitrogen source 712. The plasma is used to modify the silicon oxide film 706 by nitridation and sputtering. In the example shown, the nitrogen source 712 comprises nitrogen and ammonia. In other examples, any other suitable nitrogen source can be used. Examples include hydrazine and cyanide. Nitrogen ions in the plasma can be used to sputter the silicon oxide film 706. In some examples, the plasma further comprises an inert gas to help sputter the silicon oxide film 706. Example inert gases include helium, neon, argon, krypton, and xenon. As a result of the modification step, the silicon oxide film 706 is chemically modified to form a first layer of nitridated oxide 714A. Additionally, reentrant structures 710 are removed and the profile of the nitridated oxide 714A is modified to a V-shape.

[0125] Any suitable plasma conditions can be used to perform the modification step and form first layer of nitridated oxide 714A. Examples include radiofrequency power of 50 to 6000 W, frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF component and a LFcomponent of radiofrequency energy. Examples powers for HF radiofrequency energy include radiofrequency powers of 50 to 6000 W. Examples powers for LF radiofrequency energy include radiofrequency powers of 0 to 3000 W. Further, the modification step can be performed at any suitable pressure, such as pressures of 0.5 Torr to 20 Torr. In some examples, use of a relatively lower pressure during a modification step can provide a greater sputtering rate than examples that use higher pressures during a modification step.

[0126] Additional deposition cycles can be performed to continue filling gap 702 with nitridated oxide. FIG. 7D shows substrate 700 following a CVD step of a subsequent deposition cycle. The CVD step again comprises introducing TEOS 704 into a plasma to deposit additional silicon oxide film 706 onto the first layer of nitridated oxide 714A. Film growth is faster on upper sidewalls 708 of gap 702. This forms reentrant structures 710 in the silicon oxide film 706.

[0127] Continuing, FIG. 7E shows substrate 700 following a modification step of the subsequent deposition cycle. The modification step again comprises forming a plasma comprising nitrogen source 712. Nitrogen ions in the plasma impinge on the layer of silicon oxide film 706 to modify the film by nitridation and sputtering. As shown in FIG. 7E, sputtering removes the reentrant structures 710. Further, the silicon oxide film 706 is nitridated to form a second layer of nitridated oxide 714B.

[0128] Additional deposition cycles can be performed to deposit and modify additional layers of silicon-containing film. FIG. 7F shows substrate 700 after further CVD processing to fill gap 702 with nitridated oxide 714. By performing deposition cycles with a modification step that includes sputtering, gap 702 is filled without a void. Further, by modifying the silicon oxide film using a plasma comprising a nitrogen source, the silicon oxide can be nitridated to form silicon oxynitride. In this manner, gap 702 can be filled with silicon oxynitride by a CVD process that uses TEOS precursor.

[0129] FIG. 8 shows a flow diagram of another example method 800 for processing a substrate. Method 800 comprises, at 802, performing a plurality of CVD cycles to deposit a silicon-containing film on a substrate. Example silicon-containing films include silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride.

[0130] In some examples, method 800 comprises depositing the silicon- containing film into a feature, such as a gap. In some examples, at 804, the substratecomprises a feature comprising an aspect ratio of up to 5 : 1. In other examples, a feature can have any other suitable aspect ratio.

[0131] Each CVD cycle comprises, at 808, performing a CVD step by exposing the substrate to a silicon-containing precursor under conditions configured to convert the silicon-containing precursor into the silicon-containing film. Example CVD processes include PECVD and thermal CVD. Performing the CVD step at 808 can comprise depositing any suitable silicon-containing film. In some examples, at 810, method 800 comprises depositing one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, or silicon oxycarbonitride. In some examples, at 812, method 800 comprises exposing the substrate to TEOS. TEOS can be introduced into a plasma in examples that include PECVD. As described above, TEOS can be used to deposit a silicon oxide film that can be nitridated in a modification step. In other examples, any other suitable silicon- containing precursor can be used. Examples include those listed above. In some examples, an oxidant is used to react with the silicon-containing precursor. Examples include molecular oxygen, nitrous oxide, water, hydrogen peroxide, and carbon dioxide. An example precursor for providing nitrogen for formation of a silicon oxynitride film is nitrous oxide. When using TEOS, a silicon oxynitride film can be formed on the substrate by forming a plasma using a nitrogen source to nitridate a silicon oxide film in a modification step.

[0132] In some examples, at 814, the CVD step comprises depositing a layer of silicon-containing film comprising a thickness of 1 nm to 10 nm. In other examples, a thickness outside this range can be used.

[0133] In examples where CVD step 808 comprises using PECVD, example plasma conditions include radiofrequency power of 50 to 6000 W. Example frequencies for the radiofrequency plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. Examples of frequencies for a HF component include frequencies of 3 MHz to 300 MHz. Examples of frequencies for a LF component can include frequencies of 3 MHz and below. Any suitable radiofrequency power can be used. Examples include HF radiofrequency power of 50 to 6000 W and LF radiofrequency power of 0 to 3000 W.

[0134] As mentioned above, use of relatively lower power radiofrequency energy (e.g., power of 50 W to 3000 W) can help deposit a relatively lower density silicon oxide film that is more susceptible to nitridation than a higher density film.Further, a relatively lower density silicon-containing film can be more easily sputtered than a relatively higher density film. Thus, in some examples, the CVD step comprises forming a plasma using a radiofrequency power of 50 W to 3000 W. In some more specific examples, a radiofrequency power of 500 to 1000 W can be used. In other examples, radiofrequency power outside these ranges can be used. Further, any suitable pressure can be used to perform the CVD step at 804. Examples include pressures of 0.5 Torr to 20 Torr.

[0135] Continuing, the CVD cycle further comprises, at 820, performing a modification step by using a plasma to impinge ions of the silicon-containing film to modify the film. Modifying the silicon-containing film includes at least modifying the profile of the silicon-containing film or modifying the composition of the silicon- containing film. Thus, in some examples, step 820 comprises modifying the profile of the silicon-containing film. Additionally or alternatively, in some examples, step 820 comprises modifying the composition of the silicon-containing film.

[0136] The modification step 820 can be performed in any suitable manner. In some examples, at 822, step 820 comprises forming a plasma using an inert gas to change a profile of a reentrant structure of the silicon-containing film by sputtering. Any suitable inert gas can be used. Examples include Ar, He, Ne, Kr, and Xe. Any suitable sputtering conditions can be used. Examples of suitable pressures include pressures of 0.5 Torr to 20 Torr. Examples of suitable temperatures include temperatures of 250 °C to 650 °C. Example frequencies for the radiofrequency plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the radiofrequency energy is supplied at a plurality of different frequencies and / or powers. For example, as described above, a plasma can comprise a LF component and a HF component. Examples of frequencies for the HF component can include frequencies of 3 MHz to 300 MHz. The HF component can comprise a power of 50 to 6000 W in some examples. Examples of frequencies for the LF component can include frequencies of 3 MHz and below. The LF component can comprise a power of 0 to 3000 W in some examples. Use of a LF component in addition to a HF component can provide a greater sputtering rate than examples that omit LF radiofrequency energy. Further, using a HF component (e.g., 27 MHz or 13 MHz) can help provide a higher concentration of inert gas ions and a greater sputtering rate than use of LF component (e.g., 400 kHz). Increasing the power of the HF component can help increase the concentration of inert gas ions in the plasma to increase the sputtering rate. Further,increasing the power of the LF component can increase the kinetic energy of inert gas ions in the plasma to help increase the sputtering rate.

[0137] In some examples, at 824, the silicon-containing film deposited in the CVD step at 804 is a silicon oxide film. In such examples, the modification step 820 alternatively or additionally can comprise nitridating the silicon oxide film. In some such examples, at 826, the modification step comprises forming a plasma using one or more of molecular nitrogen or ammonia. In other examples, a different nitrogen source alternatively or additionally can be used, such as hydrazine or a CN-containing species (e.g. hydrogen cyanide). Nitrogen ions in the plasma impinge on the silicon-containing film to implant nitrogen into the silicon oxide film. Any suitable plasma conditions can be used. Example frequencies for the plasma include frequencies of 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the plasma is formed using an HF radiofrequency energy component and a LF radiofrequency energy component. Any suitable radiofrequency power can be used. In some examples, the HF component can comprise a radiofrequency power of 50 to 6000 W. Further, in some examples, the LF component can comprise a radiofrequency power of 0 to 3000 W. In other examples, a silicon nitride or silicon oxynitride film formed from a silane-based precursor can be further nitridated. In yet further examples, any other suitable silicon-containing film can be nitridated.

[0138] In some examples, processing conditions of the modification step can be adjusted to control the nitrogen concentration in silicon oxynitride film. For example, increasing the power of the HF component can help increase the concentration of nitrogen ions in the plasma and increase the nitridation rate. Further, increasing the power of the LF component can increase the kinetic energy of nitrogen gas ions in the plasma to help break Si-0 bonds in a silicon oxide film. This can help increase the nitridation rate. In a more specific example, the radiofrequency plasma is formed using a HF component of 13.56 MHz and a LF component of 400 kHz. Use of an LF component in addition to a HF component can provide a greater nitridation rate than examples that omit LF radiofrequency energy. Additionally, using a longer duration modification step can help increase nitridation. In some examples, at 828, the modification step comprises nitridating and sputtering the silicon oxide film. An example of a CVD process that includes nitridating and sputtering in a modification step is described above with regard to FIGS. 7A-5E. This can help deposit a silicon oxynitride film in a void-free gapfill process using TEOS as a precursor.

[0139] Method 800 can comprise performing any suitable number of CVD cycles at 802. In some examples, at 830, method 800 optionally comprises performing a CVD cycle that omits the modification step.

[0140] FIG. 9 schematically shows an example processing tool 900 that can implement the examples described above with reference to FIGS. 2-6. Processing tool 900 comprises a processing chamber 902 and a substrate support 904 within the processing chamber. The substrate support 904 is configured to support a substrate 906 disposed within processing chamber 902. The substrate support 904 comprises a substrate heater 908. In other examples, a heater can be omitted, or can be located elsewhere within processing chamber 902.

[0141] The processing tool 900 further comprises a showerhead 910. In other examples, a processing tool can comprise a nozzle or other apparatus for introducing gas into processing chamber 902, as opposed to or in addition to a showerhead. In some examples, the processing tool 900 comprises a heater configured to heat showerhead 910. The processing tool 900 further comprises flow control hardware 912. The flow control hardware 912 connects processing gas source(s) to the processing chamber. In the depicted example, the flow control hardware 912 connects a silicon-containing film precursor source 916, an optional nitrogen source 918, an optional oxidant source 920, and an inert gas source 924 to the processing chamber. The flow control hardware 912 can include any suitable components. Examples include mass flow controllers, valves, and conduits. For example, the flow control hardware 912 can comprise one or more valves controllable to place a selected gas source or selected gas sources in fluid connection with showerhead 910. The flow control hardware 912 also can comprise one or more mass flow controllers or other controllers for controlling a mass flow rate of gas.

[0142] The silicon-containing film precursor source 916 comprises any suitable precursor compound(s) for forming a silicon-containing film. Examples silicon- containing films include films comprising silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride. In some examples, the silicon-containing precursor source comprises TEOS 916A. As described above, use of TEOS can help deposit a high-quality film at relatively low cost. Further examples of silicon-containing film precursors include those listed above. In some examples, two or more film precursor sources can be used to provide a respective two or more film precursors. An example precursor forproviding nitrogen for formation of a silicon nitride film or silicon oxynitride film is nitrous oxide. Optionally, a carbon-containing precursor source (not shown) can be used to provide a carbon-containing precursor for forming a silicon-containing film that includes carbon. Examples of such silicon-containing films include silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride. Examples of carbon-containing precursors for forming such films include alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alkyl halides, alkyl amines, and alkyl diamines.

[0143] The optional nitrogen source 918 comprises any suitable nitrogen source that can be introduced into a plasma for use in nitridating a film. In some examples, nitrogen source comprises molecular nitrogen 918A. In some examples, nitrogen source comprises ammonia 918B. Examples of nitrogen sources further include hydrazine and cyanide. In some examples, nitrogen source 918 comprises two or more nitrogencontaining compounds. In examples that include modifying a profile of a film by sputtering without nitridation, nitrogen source 918 can be omitted.

[0144] The optional oxidant source 920 comprises any suitable oxidant for forming silicon oxide, silicon oxynitride, silicon oxycarbide, or silicon oxycarbonitride films. Examples of oxidants can include molecular oxygen, nitrous oxide, water, hydrogen peroxide, and carbon dioxide.

[0145] The inert gas source 924 can comprise any suitable inert gas. Examples include argon, helium, neon, krypton, and xenon. In some examples, using a heavier inert gas, such as Ar, Kr, or Xe, can help increase a sputtering rate of the silicon- containing film compared to use of a lighter inert gas, such as He or Ne.

[0146] The processing tool 900 further comprises an exhaust system 932. The exhaust system 932 is configured to exhaust gases from the processing chamber 902. The exhaust system 932 can comprise any suitable hardware, including one or more low vacuum pumps, one or more high vacuum pumps, and one or more valves for controlling an exhaust flow. Together, flow control hardware 912 and exhaust system 932 can be operated to achieve a selected pressure in processing chamber 902 during substrate processing. Example pressures include pressures of 0.5 Torr to 20 Torr. Further, exhaust system 932 can be operated to purge processing chamber 902.

[0147] The processing tool 900 further comprises a radiofrequency power source 934 that is electrically connected to showerhead 910. Radiofrequency power source 934 is configured to form a plasma using a gas mixture.

[0148] For example, during a CVD step, radiofrequency power source 934 can be operated to form a plasma using a gas mixture comprising one or more film precursors to deposit a silicon-containing film. Further, during a modification step, radiofrequency power source 934 can be operated to form a plasma using an inert gas to modify a profile of the silicon-containing film by sputtering. Additionally or alternatively, during the modification step, radiofrequency power source 934 can be operated to form a plasma comprising a nitrogen source to modify a composition of the silicon-containing film by nitridation. In the depicted example, a capacitively coupled plasma can be formed in processing chamber 902 between showerhead 910 and substrate support 904. Radiofrequency power can be supplied to the showerhead electrode or substrate holder electrode in various examples. As shown in FIG. 9, the radiofrequency energy is provided to showerhead 910, and substrate support 904 is configured as a grounded opposing electrode. In other examples, the radiofrequency power source 934 can supply radiofrequency power to substrate support 904, and showerhead 910 can be grounded. In such examples, supplying radiofrequency power to substrate support 904 can increase a sputtering rate of the silicon-containing film. In some examples, the radiofrequency power source 934 can be operated to pulse the plasma using any suitable duty cycle. In other examples, the radiofrequency power source 934 can be operated to form a continuous-wave plasma, instead of a pulsed plasma. In some examples, a remote plasma chamber can be used to form a remote plasma. The remote plasma can be introduced into the processing chamber during the modification step.

[0149] The processing tool 900 further includes include a matching network 936 for impedance matching of the radiofrequency power source 934. The radiofrequency power source 934 can be configured to provide radiofrequency energy of any suitable frequency and power. Examples frequencies include 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the radiofrequency power source 934 is configured to operate at a plurality of different frequencies and / or powers. For example, as described above, a plasma can comprise a LF radiofrequency energy component and a HF radiofrequency energy component. Examples of frequencies for the LF radiofrequency energy component can include frequencies of 3 MHz and below. The LF radiofrequency energy component can comprise a power of 0 to 3000 W, in some examples. Further, the HF radiofrequency energy component can comprisefrequencies of 3 MHz to 300 MHz. The HF radiofrequency energy component can comprise a power of 50 to 6000 W, in some examples.

[0150] The processing tool 900 further comprises a controller 950 configured to control operation of the processing tool. The controller 950 is operatively coupled to the substrate heater 908, the flow control hardware 912, the exhaust system 932, and the radiofrequency power source 934. The controller 950 is configured to control various functions of processing tool 900 to perform deposition cycles including CVD steps and modification steps. For example, the controller 950 is configured to control processing tool 900 to operate the substrate heater 908 to heat a substrate to a desired temperature. Examples include temperatures of 250 °C to 1200 °C. The controller 950 also is configured to operate the flow control hardware 912 to flow a selected gas or mixture of gases at a selected rate into the processing chamber 902. The controller 950 is further configured to operate the exhaust system 932 to remove gases from processing chamber 902. The controller 950 can, for example, control the exhaust system 932 and / or the flow control hardware 912 to purge the processing chamber 902. The controller 950 is configured to operate the radiofrequency power source 934 to form a plasma, as well as to control any other suitable functions of processing tool 900.

[0151] The controller 950 can operate the processing tool 900 to perform a plurality of deposition cycles to process substrate 906. The controller 950 can operate the processing tool 900 to perform CVD steps and modification steps. For example, in a CVD step, the controller 950 is configured to operate the flow control hardware 912 to introduce a silicon-containing precursor from silicon-containing precursor source 916 into the processing chamber 902. This is performed under conditions configured to convert the silicon-containing precursor into a silicon-containing film on substrate 906. For example, during the CVD step, the controller 950 can operate the substrate heater 908 to heat a substrate to a desired temperature to facilitate formation of the silicon- containing film. Additionally or alternatively, during the CVD step, the controller can operate the radiofrequency power source 934 to form a plasma to facilitate formation of the silicon-containing film. During a modification step, the controller 950 can operate the flow control hardware 912 and the radiofrequency power source 934 to form a plasma to impinge ions on the silicon-containing film. This can modify the profile of the silicon-containing film by sputtering or modify the composition of the silicon- containing film by nitridation. The controller 950 can comprise any suitable computing system. Example computing systems are described below with reference to FIG. 10.

[0152] Thus, by performing CVD cycles that include modifying a profile of a film by sputtering, a gap in a substrate can be filled without forming a void. This provides for gapfill using CVD to fill gaps with relatively higher aspect ratios (e.g., 0.5: 1 or greater) than examples that omit modification steps. Additionally, by performing CVD cycles that include modifying a composition of a film by nitridation, a silicon oxynitride film can be deposited in a cyclic CVD process that uses TEOS. This allows for lower costs than examples that use more expensive aminosilane precursors. Further, the modification step can include both sputtering and nitridation to deposit a silicon oxynitride film into a gap using a cyclic CVD process.

[0153] FIG. 10 schematically shows a non-limiting example of a computing system 1000 that can enact one or more of the methods and processes described above. Computing system 1000 is shown in simplified form. Computing system 1000 can take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network accessible server computers.

[0154] Computing system 1000 includes a logic subsystem 1002 and a storage subsystem 1004. Computing system 1000 can optionally include a display subsystem 1006, input subsystem 1008, communication subsystem 1010, and / or other components not shown in FIG. 10. Controller 950 is an example of computing system 1000.

[0155] Logic subsystem 1002 includes one or more physical devices configured to execute instructions. For example, the logic machine can be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions can be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0156] The logic machine can include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine can include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of the logic machine can be single-core or multi-core, and the instructions executed thereon can be configured for sequential, parallel, and / or distributed processing. Individual components of the logic machine optionally can be distributed among two or more separate devices, which can be remotely located and / or configured for coordinated processing. Aspects of the logicmachine can be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

[0157] Storage subsystem 1004 includes one or more physical devices configured to hold instructions 1012 executable by the logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of storage subsystem 1004 can be transformed — e.g., to hold different data.

[0158] Storage subsystem 1004 can include removable and / or built-in devices. Storage subsystem 1004 can include optical memory (e.g., CD, DVD, HD-DVD, Blu- Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage subsystem 1004 can include volatile, nonvolatile, dynamic, static, read / write, read-only, random-access, sequential-access, location-addressable, file-addressable, and / or content-addressable devices.

[0159] It will be appreciated that storage subsystem 1004 includes one or more physical devices. However, aspects of the instructions described herein alternatively can be propagated by a communication medium (e.g., an electromagnetic signal, an optical signal, etc.) that is not held by a physical device for a finite duration.

[0160] Aspects of logic subsystem 1002 and storage subsystem 1004 can be integrated together into one or more hardware-logic components. Such hardware-logic components can include field-programmable gate arrays (FPGAs), program- and application-specific integrated circuits (PASIC / ASICs), program- and applicationspecific standard products (PSSP / ASSPs), system-on-a-chip (SOC), and complex programmable logic devices (CPLDs), for example.

[0161] When included, display subsystem 1006 can be used to present a visual representation of data held by storage subsystem 1004. This visual representation can take the form of a graphical user interface (GUI). As the herein described methods and processes change the data held by the storage machine, and thus transform the state of the storage machine, the state of display subsystem 1006 can likewise be transformed to visually represent changes in the underlying data. Display subsystem 1006 can include one or more display devices utilizing virtually any type of technology. Such display devices can be combined with logic subsystem 1002 and / or storage subsystem 1004 in a shared enclosure, or such display devices can be peripheral display devices.

[0162] When included, input subsystem 1008 can comprise or interface with one or more user-input devices such as a keyboard, mouse, or touch screen. In some examples, the input subsystem can comprise or interface with selected natural user input (NUI) componentry. Such componentry can be integrated or peripheral, and the transduction and / or processing of input actions can be handled on- or off-board. Example NUI componentry can include a microphone for speech and / or voice recognition, and an infrared, color, stereoscopic, and / or depth camera for machine vision and / or gesture recognition.

[0163] When included, communication subsystem 1010 can be configured to communicatively couple computing system 1000 with one or more other computing devices. Communication subsystem 1010 can include wired and / or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem can be configured for communication via a wireless telephone network, or a wired or wireless local- or wide-area network. In some examples, the communication subsystem can allow computing system 1000 to send and / or receive messages to and / or from other devices via a network such as the Internet.

[0164] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific examples or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein can represent one or more of any number of processing strategies. As such, various acts illustrated and / or described can be performed in the sequence illustrated and / or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes can be changed.

[0165] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems and configurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

Claims

CLAIMS:

1. A method of performing chemical vapor deposition (CVD), the method comprising: performing a plurality of CVD cycles to form a silicon-containing film on a substrate, each CVD cycle of the plurality of CVD cycles comprising: performing a CVD step by exposing the substrate to a flow of a silicon- containing precursor under conditions configured to convert the silicon-containing precursor into the silicon-containing film on the substrate, and performing a modification step by using a plasma to impinge ions on the silicon-containing film to at least modify a profile of the silicon-containing film or modify a composition of the silicon-containing film.

2. The method of claim 1, wherein the modification step comprises forming the plasma using an inert gas to change a profile of a reentrant structure of the silicon- containing film by sputtering.

3. The method of claim 2, wherein the silicon-containing precursor comprises a silane-based precursor, and the silicon-containing film comprises silicon oxide, silicon oxynitride, or silicon nitride.

4. The method of claim 1, wherein the plasma of the modification step is formed using radiofrequency energy comprising a lower frequency energy component of 3 MHz or lower and a higher frequency energy component of 3 MHz to 300 MHz.

5. The method of claim 1, wherein the plasma of the CVD step is formed using radiofrequency energy comprising a high frequency component of 3 MHz to 300 MHz and omits a low frequency component.

6. The method of claim 1, wherein the silicon-containing film deposited in the CVD step is a silicon oxide film, wherein the silicon-containing precursor comprises tetraethlyorthosilicate, and wherein the modification step comprises nitridating the silicon oxide film.

7. The method of claim 6, wherein nitridating the silicon oxide film comprises forming the plasma using one or more of ammonia, molecular nitrogen, hydrazine, or a CN-containing species.

8. The method of claim 6, wherein the modification step comprises sputtering and modifying the composition of the silicon-containing film.

9. The method of claim 1, wherein modifying the composition of the silicon- containing film comprises nitridating the silicon-containing film.

10. The method of claim 1, wherein the CVD step comprises forming a silicon oxide, a silicon oxynitride, or a silicon nitride film using a silane-based precursor, and wherein modifying the composition of the silicon-containing film by nitridating the silicon-containing film comprises nitridating the silicon oxide, the silicon oxynitride, or the silicon nitride film.

11. The method of claim 1, further comprising performing a CVD cycle that omits the modification step.

12. A method of performing plasma-enhanced chemical vapor deposition (CVD), the method comprising: performing a plurality of CVD cycles, a CVD cycle of the plurality of CVD cycles comprising: performing a CVD step by introducing a flow of tetraethylorthosilicate (TEOS) into a plasma to deposit a silicon oxide film onto a substrate, and after performing the CVD step, performing a nitridation step by exposing the substrate to a plasma comprising a nitrogen source to nitridate the silicon oxide film, thereby forming a silicon oxynitride film.

13. The method of claim 12, wherein the nitrogen source comprises one or more of nitrogen, ammonia, hydrazine, or a CN-containing species.

14. The method of claim 12, wherein the plasma comprising the nitrogen source is formed using radiofrequency power comprising a low frequency energy component of 3 MHz or lower and a high frequency energy component of 3 MHz to 300 MHz.

15. The method of claim 12, wherein the silicon oxynitride film comprises a percentage of nitrogen that is up to 30% by atomic percentage.

16. The method of claim 12, wherein exposing the substrate to the plasma further comprises sputtering a reentrant structure of the silicon oxide film.

17. A chemical vapor deposition (CVD) tool, comprising: a processing chamber; a substrate support disposed in the processing chamber; flow control hardware configured to control gas flows from one or more gas sources into the processing chamber; and a controller configured to perform a plurality of CVD cycles, each CVD cycle of the plurality of CVD cycles comprising a CVD step and a modification step, the controller configured to in each CVD step, operate the flow control hardware to introduce a silicon-containing precursor from a silicon-containing precursor source into the processing chamber to expose a substrate to the silicon-containing precursor under conditions configured to convert the silicon-containing precursor into a silicon- containing film on the substrate, and in each modification step, operate the flow control hardware and a radiofrequency power source to form a plasma to impinge ions on the surface of the silicon-containing film to at least modify a profile of the silicon-containing film or modify a composition of the silicon-containing film.

18. The CVD tool of claim 17, wherein the controller is configured to operate the flow control hardware and the radiofrequency power source to form the plasma using an inert gas to change a profile of a reentrant portion of the silicon-containing by sputtering.

19. The CVD tool of claim 17, further comprising the silicon-containing precursor source, wherein the silicon-containing precursor source comprises tetraethylorthosilicate or silane, and wherein the controller is further configured to, in the modification step, operate the flow control hardware and the radiofrequency power source to modify the deposited silicon-containing film using one or more of argon, helium, nitrous oxide, ammonia, oxygen, or molecular nitrogen.

20. The CVD tool of claim 17, further comprising the silicon-containing precursor source, wherein the silicon-containing precursor source comprises silane, and wherein the controller is further configured to, in the modification step, operate the flow control hardware and the radiofrequency power source to modify the deposited silicon- containing film using one or more of argon, helium, nitrous oxide, ammonia or molecular nitrogen.

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