Bottom-up gap filling using gaskets

Abstract

Examples disclosed relate to performing a partial gap fill process in a bottom-up manner using atomic layer deposition (ALD). One example provides a method of partially filling a gap in a substrate. The method includes depositing a silicon nitride sub-conformal layer in a first portion of the gap and not in a second portion of the gap. The first portion extends from a top of the gap to a selected depth within the gap. The second portion extends from a selected depth to a bottom of the gap. The method further includes performing a plurality of ALD cycles to deposit a silicon-containing oxide in a second portion of the gap. The ALD cycle includes exposing the substrate to a silicon-containing precursor and reacting the silicon-containing precursor with an oxidizing agent to deposit a silicon-containing oxide on the surface in the second portion of the gap.

Description

Background Art

[0001] The electronic device manufacturing process involves many steps of material deposition, patterning, and removal to form integrated circuits on substrates. Various methods can be used to deposit material films onto substrates. As an example, atomic layer deposition (ALD) deposits films in a layer-by-layer manner using cycles. In an ALD cycle, a film precursor is adsorbed onto the surface of a substrate placed in a processing chamber. Excess film precursor is removed from the chamber. The adsorbed film precursor is then chemically converted to a film on the substrate. In this way, highly conformal films of a target thickness can be grown. Summary of the Invention

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

[0003] Disclosed examples relate to performing a partial gap fill process in a bottom-up manner using atomic layer deposition (ALD). One example provides a method for partially filling a gap in a substrate disposed in a process chamber. The method includes depositing a sub-conformal layer of silicon nitride in a first portion of the gap and not depositing it in a second portion of the gap. The first portion extends from a top of the gap to a selected depth within the gap. The second portion extends from the selected depth to a bottom of the gap. The method also includes performing multiple ALD cycles to deposit a silicon-containing oxide in the second portion of the gap. An ALD cycle in the one or more ALD cycles includes exposing the substrate to a silicon-containing precursor so that the silicon-containing precursor adsorbs to a surface in the second portion of the gap. The ALD cycle in the one or more ALD cycles also includes reacting the silicon-containing precursor with an oxidant to deposit the silicon-containing oxide on the surface in the second portion of the gap.

[0004] In some such examples, an ALD cycle in the one or more ALD cycles includes exposing the substrate to an inhibitor under conditions configured to deposit the inhibitor into the gap such that a concentration of the inhibitor deposited at a first depth within the gap is greater than a concentration of the inhibitor deposited at a second depth within the gap, the second depth being within the second portion of the gap and further from the top of the gap than the first depth.

[0005] In some such examples, exposing the substrate to the inhibitor additionally or alternatively includes exposing the substrate to a fluorine-containing inhibitor.

[0006] In some such examples, the fluorine-containing inhibitor additionally or alternatively includes one or more of molecular fluorine, hydrogen fluoride, boron trifluoride, phosphorus trifluoride, nitrogen trifluoride, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides, chalcogen chlorides, or interhalogen compounds.

[0007] In some such examples, the method additionally or alternatively includes removing the silicon nitride subconformal layer from the first portion of the gap after depositing the silicon-containing oxide.

[0008] In some such examples, depositing the silicon nitride subconformal layer additionally or alternatively includes: exposing the substrate to one or more of a halosilane precursor or an aminosilane precursor; purging the process chamber; and forming a plasma including a reactive nitrogen species.

[0009] In some such examples, forming the plasma additionally or alternatively includes forming the plasma for a duration in a range of 0.05 to 60 seconds.

[0010] In some such examples, the substrate additionally or alternatively includes a stack of alternating layers of silicon and silicon germanium, a stack of alternating layers of polysilicon and silicon oxide, or a stack of alternating layers of silicon nitride and silicon oxide.

[0011] In some such examples, the gap additionally or alternatively includes a trench for forming a trench isolation region in the logic device.

[0012] Another example provides a method for processing a substrate comprising a gap. The method includes depositing a liner in a first portion of the gap and not depositing the liner in a second portion of the gap, the first portion extending from a top of the gap to a selected depth within the gap, and the second portion extending from the selected depth to a bottom of the gap. The method also includes performing a plurality of ALD cycles to deposit a silicon-containing oxide in the second portion of the gap. An ALD cycle in the plurality of ALD cycles includes exposing the substrate to an inhibitor under conditions configured to deposit the inhibitor into the gap such that a concentration of the inhibitor deposited at a first depth is greater than a concentration of the inhibitor deposited at a second depth within the gap. The second depth is within the second portion of the gap and is further from the top of the gap than the first depth.

[0013] In some such examples, the method further includes removing the liner from the first portion of the gap.

[0014] In some such examples, depositing the liner additionally or alternatively includes depositing a silicon nitride liner.

[0015] In some such examples, depositing the liner additionally or alternatively includes forming a plasma.

[0016] In some such examples, the ALD cycle in the plurality of ALD cycles additionally or alternatively includes exposing the substrate to a silicon-containing precursor to adsorb the silicon-containing precursor onto the substrate and then oxidizing the silicon-containing precursor.

[0017] In some such examples, the method additionally or alternatively includes performing an ALD cycle in the plurality of ALD cycles that omits exposing the substrate to the inhibitor.

[0018] In some such examples, the inhibitor additionally or alternatively includes one or more of molecular fluorine, hydrogen fluoride, boron trifluoride, phosphorus trifluoride, nitrogen trifluoride, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides, chalcogen chlorides, or interhalogen compounds.

[0019] Another example provides a structure formed on a substrate during an integrated circuit manufacturing process. The structure includes a gap. The structure also includes a silicon nitride film disposed within a first portion of the gap. The first portion extends from an opening of the gap to a selected depth within the gap. The structure also includes an oxide film within the gap. The oxide film at least partially fills a second portion of the gap. The second portion of the gap extends from the selected depth to a bottom of the gap.

[0020] In some such examples, the silicon nitride film includes a halogenated surface.

[0021] In some such examples, the structure is additionally or alternatively part of a three-dimensional memory structure.

[0022] In some such examples, the silicon nitride film additionally or alternatively includes The thickness is within the range of . BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figures 1A-1F The structure formed by an exemplary process of utilizing a liner to achieve bottom-up gap filling is schematically shown.

[0024] Figure 2Schematically shows the use of relatively short RF power duration (compared to Figure 1B Example) and the structure formed by depositing the liner.

[0025] Figure 3 Schematically shows the use of relatively long RF power duration (compared to Figure 1B Example) and the structure formed by depositing the liner.

[0026] Figures 4A-4C A flow chart is shown describing an exemplary method of partially filling a gap by forming a liner in a first portion of the gap followed by depositing silicon oxide in a second portion of the gap.

[0027] Figure 5 A block diagram of an exemplary ALD processing tool is shown.

[0028] Figure 6 A block diagram of an exemplary computing system is shown. DETAILED DESCRIPTION

[0029] The term "aspect ratio" generally refers to the ratio between the depth of a substrate feature and the average width of the feature. An exemplary substrate feature is a gap.

[0030] The term "atomic layer deposition" (ALD) generally refers to a process that forms a film as one or more separate layers on a substrate by sequentially conformally adsorbing precursors to a substrate and then reacting the adsorbed precursors to form a film layer. Examples of ALD processes include plasma-enhanced ALD (PEALD) and thermal ALD (TALD). PEALD and TALD utilize plasma of a reactive gas and heat, respectively, to promote the chemical conversion of adsorbed precursors to a film on the substrate. The terms "growth," "deposition," and variations thereof may also be used to refer to film formation.

[0031] The term "ALD cycle" generally refers to a series of processes used to form a layer of film in an ALD process.

[0032] The terms "ALD cycle including an inhibitor" and "inhibited ALD cycle" generally refer to an ALD cycle that includes the introduction of an inhibitor into the processing chamber during the cycle.

[0033] The term "ALD tool" generally refers to a machine including a processing chamber and other hardware configured to perform ALD.

[0034] The term "chemical vapor deposition" (CVD) generally refers to a process in which a solid film is formed on a substrate by directing a flow of one or more precursor gases onto the substrate surface under conditions configured to cause film formation. Plasma-enhanced chemical vapor deposition (PECVD) utilizes plasma to promote film formation.

[0035] The term "conformal film" generally refers to a film having a consistent thickness at different locations on the substrate surface.

[0036] The term "flow control hardware" generally refers to components that fluidly connect one or more chemical sources to a process chamber. For example, the flow control hardware may include one or more mass flow controllers and / or valves.

[0037] The term "gap" generally refers to a recessed portion formed in a substrate surface. Examples of gaps include trenches, holes, and vias. When referring to a gap, the term "first portion" generally refers to the region of the gap extending from the top of the gap to a selected depth within the gap. The term "second portion" generally refers to the region of the gap extending from the selected depth to the bottom of the gap.

[0038] The term "gap fill" generally refers to a process that uses a material to fill a gap on a substrate. The term "partial gap fill" generally refers to a process that partially fills a gap from the bottom of the gap to a selected depth within the gap.

[0039] The term "inhibitor" generally refers to a compound that can be introduced into a processing chamber, can adsorb to a substrate surface, and, when adsorbed to the substrate surface, inhibits the ALD growth of an oxide film. Suitable inhibitors for inhibiting the ALD growth of oxide films include halogen-containing inhibitors, carbon-containing inhibitors, and nitrogen-containing inhibitors. The term "inhibitor" is used to refer to inhibitor molecules, reactive inhibitor species generated by introducing inhibitor molecules into a plasma, and inhibitor species adsorbed to a substrate surface.

[0040] Examples of nitrogen-containing inhibitors may include nitrogen (N2), ammonia (NH3), nitrogen and hydrogen mixtures, amines, diamines, and amino alcohols.

[0041] Examples of halogen-containing inhibitors may include fluorine-containing inhibitors, chlorine-containing inhibitors, bromine-containing inhibitors, and iodine-containing inhibitors. Examples of fluorine-containing inhibitors may include molecular fluorine (F2), hydrogen fluoride (HF), boron trifluoride (BF3), phosphorus trifluoride (PF3), nitrogen trifluoride (NF3), chlorine trifluoride (ClF3), chlorine pentafluoride (ClF5), and chalcogen fluorides, such as sulfur tetrafluoride (SF4) and sulfur hexafluoride (SF6). Further examples of fluorine-containing inhibitors may include chlorofluorocarbons (e.g., trichlorofluoromethane CCl3F), fluorocarbons (e.g., carbon tetrafluoride CF4 or hexafluoroethane C2F6), and hydrofluorocarbons (e.g., difluoromethane CH2F2). Further examples of chlorine-containing inhibitors may include chalcogen chlorides, such as sulfur monochloride (S2Cl2) and sulfur dichloride (SCl2). Other examples of halogen-containing inhibitors may include chlorine (Cl2), hydrogen chloride (HCl), carbon tetrachloride (CCl4), bromine (Br2), hydrogen bromide (HBr), iodine (I2), hydrogen iodide (HI), and 1,2-diiodoethane (C2H4I2).

[0042] Examples of suitable carbon-containing inhibitors may include alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alcohols, aldehydes, esters, ethers, ketones, aldehydes, alkyl halides, alkylamines, and alkyldiamines. In some examples, the carbon-containing inhibitor may include a compound having the general formula C n H 2n+2 wherein n=1 to 10. Examples of suitable alkanes may include methane, ethane, propane, butane, heptane, hexane, and substituted alkanes. Other examples of carbon-containing inhibitors may include alkenes, alkynes, cyclic hydrocarbons, aromatics, alcohols, diols, aldehydes, esters, ethers, ketones, alkyl halides, alkylamines, or alkyldiamines. In still other examples, the carbon-containing inhibitor may include a mixture of carbon-containing inhibitors. Suitable alkenes (C n H 2n , wherein n=2 to 10, examples of alkenes having a single carbon-carbon double bond may include ethylene, propylene, and butene. Suitable alkynes (C n H 2n-2, where n=2 to 10, for alkynes having a single carbon-carbon triple bond) may include acetylene, propyne, and butyne. Examples of suitable cyclic hydrocarbons may include cyclobutene, cyclopentane, and cyclohexane. Examples of suitable aromatics may include benzene, toluene, pyridine, and pyrimidine. Examples of suitable alcohols may include methanol, ethanol, and propanol. Examples of suitable diols may include ethylene glycol, propylene glycol, and hydroquinone. Examples of suitable aldehydes may include formaldehyde and acetaldehyde. Examples of suitable esters may include ethyl formate, methyl acetate, and ethyl acetate. Examples of suitable ethers may include diethyl ether, methyl phenyl ether, and aromatic ethers such as furan. Examples of suitable ketones may include acetone and methyl ethyl ketone. Examples of suitable alkyl halides may include ethyl fluoride, isopropyl bromide, and tert-butyl chloride. Examples of suitable alkylamines may include methylamine, dimethylamine, trimethylamine, and piperidine. Examples of suitable alkyldiamines may include ethylenediamine and 1,3-diaminopropane.

[0043] The term "liner" generally refers to a sub-conformal layer of film deposited in the gap to inhibit or prevent oxide film growth. Liners can include, for example, silicon nitride (Si3N4) films, silicon carbonitride (SiC (1-x) N (1.333x) , 0<x<1, hereinafter referred to as SiCN) film, silicon carbide (SiC) film, or silicon oxynitride (SiO x N y , 0≤x≤2, 0≤y≤1.33, hereinafter referred to as SiON) film.

[0044] The term "metal-containing precursor" generally refers to any material that can be introduced into a processing chamber in the vapor phase to form a metal oxide film on a substrate. Examples of such metal-containing precursors include aluminum-containing precursors, gallium-containing precursors, titanium-containing precursors, vanadium-containing precursors, zinc-containing precursors, zirconium-containing precursors, hafnium-containing precursors, and tungsten-containing precursors, which can be used to form aluminum oxide (Al2O3), gallium oxide (Ga2O3), titanium dioxide (TiO2), vanadium dioxide (VO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), hafnium dioxide (HfO2), and tungsten trioxide (WO3), respectively.

[0045] Examples of aluminum-containing precursors may include trimethylaluminum (Al(CH 3 ) 3 ).

[0046] Examples of titanium-containing precursors may include titanium tetrachloride (TiCl 4 ), and titanium isopropoxide (Ti(OCH(CH 3 ) 2 ) 4 ).

[0047] Examples of the vanadium-containing precursor may include tetrakis(ethylmethylamido)vanadium(IV).

[0048] Examples of zinc-containing precursors may include diethylzinc ((C2H5)2Zn).

[0049] Examples of the zirconium-containing precursor may include tetrakis(dimethylamido)zirconium(IV).

[0050] Exemplary hafnium-containing precursors may include hafnium tetrachloride (HfCl 4 ), tetrakis(diethylamino)hafnium (Hf(N(C 2 H 5 ) 2 ) 4 ), and tetrakis(tert-butyloxide)hafnium (Hf(OC(CH 3 ) 3 ) 4 ).

[0051] Examples of tungsten-containing precursors may include tungsten hexafluoride (WF 6 ), tungsten hexachloride (WCl 6 ), and tungsten hexacarbonyl (W(CO) 6 ).

[0052] The term "non-conformal" generally refers to a film comprising a non-uniform thickness.

[0053] The term "oxidant" generally refers to a gaseous substance containing oxygen that can be used to react with the film precursor to form an oxide film. Examples of oxidants include molecular oxygen (O2), water vapor (H2O), hydrogen peroxide (H2O2), ozone (O3), nitrous oxide (N2O), and other nitrogen oxides.

[0054] The term "oxide film" generally refers to a film containing oxygen and an oxidizing species deposited on a substrate surface. Examples of oxide films include silicon-containing oxide films. Examples of silicon-containing oxide films include silicon dioxide (SiO2), silicon oxynitride, and silicon oxycarbide (SiO x C y , 0≤x≤2, y=1-0.5x). Examples of the oxide film also include metal oxide films, such as aluminum oxide (Al2O3), gallium oxide (Ga2O3), titanium dioxide (TiO2), vanadium dioxide (VO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), hafnium dioxide (HfO2), and tungsten trioxide (WO3).

[0055] The term "oxide film precursor" generally refers to a material that can be introduced into a process chamber in a vapor phase to form an oxide film on a substrate in the process chamber. Examples of oxide film precursors include silicon-containing precursors that can be used to form silicon-containing oxide films. Exemplary silicon-containing oxide films include silicon dioxide, silicon oxynitride, and silicon oxycarbide films. Examples of oxide film precursors also include metal-containing precursors that can be used to form metal oxide films.

[0056] The term "plasma" generally refers to a gas containing positive ions and free electrons. The term "in situ plasma" generally refers to a plasma to which a substrate is directly exposed during substrate processing.

[0057] The term "processing chamber" generally refers to an enclosure in which chemical and / or physical processes are performed on a substrate. The pressure, temperature, and gas composition within the processing chamber may be controllable to perform the chemical and / or physical processes.

[0058] The term "purge" and its variations generally refer to the process of removing unwanted matter from a processing chamber.

[0059] The term "silicon-containing precursor" generally refers to any material that can be introduced into a processing chamber in the vapor phase to form a silicon-containing film on a substrate. Exemplary film precursors for forming silicon-containing films using PEALD may include materials having the following general structure: Wherein R1, R2 and R3 can be the same or different substituents and can include silane, siloxy group, amine, halide, hydrogen, or organic groups such as alkylamine, alkoxy, alkyl, alkenyl, alkynyl, and aromatic groups. The organosilane can include any silicon-containing precursor having a carbon-containing functional group.

[0060] Exemplary silicon-containing precursors include silane, polysilane (H3Si-(SiH2) n -SiH3), where n≥0, such as disilane, trisilane, tetrasilane, and trisilylamine.

[0061] In some examples, the silicon-containing precursor is an alkoxysilane. The alkoxysilanes that can be used include: x -Si-(OR) y An alkoxysilane wherein x=1-3, x+y=4, and each R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aromatic group; and H x (RO) y -Si-Si-(OR) y H x , is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aromatic group.

[0062] Examples of silicon-containing precursors include tetraethylorthosilicate (TEOS), tetramethoxysilane (TMOS), methylsilane, trimethylsilane (3MS), ethylsilane, butasilane, pentasilane, octylsilane, heptylsilane, hexasilane, cyclotetrasilane, cycloheptylsilane, cyclohexasilane, cyclooctylsilane, cyclopentasilane, 1,4-dioxa-2,3,5,6-tetrasilacyclohexane, diethoxymethylsilane (DEMS), diethoxysilane (DES), dimethoxymethylsilane, dimethoxysilane (DMOS), methyldiethoxysilane (MDES), methyldimethoxysilane (MDMS), tert-butoxydisilane, triethoxysilane (TES), and trimethoxysilane (TMS or TriMOS).

[0063] In some examples, the silicon-containing precursor can be a siloxane. Exemplary siloxanes include octamethylcyclotetrasiloxane (OMCTS), octamethoxydodecylsiloxane (OMODDS), tetramethylcyclotetrasiloxane (TMCTS), triethoxysiloxane (TRIES), and tetraoxymethylcyclotetrasiloxane (TOMCTS).

[0064] In some examples, the silicon-containing precursor may be an aminosilane. Exemplary aminosilane systems include bis(diethylamino)silane, di(isopropylamino)silane, bis(tert-butylamino)silane (BTBAS), (di-sec-butylamino)silane, or tris(dimethylamino)silane (3DMAS). The aminosilane precursor may have the following general formula: x -Si-(NR) y , wherein x=1-3, x+y=4, and R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aromatic group, or a hydride group.

[0065] In some examples, the silicon-containing precursor may be a halogen-containing silane. Examples of the halogen-containing silane may include dichlorosilane (H2SiCl2), hexachlorodisilane (Si2Cl6), and diiodosilane (H2SiI2).

[0066] The term "subconformal layer" generally refers to a conformal film that covers only a portion of a feature. For example, a subconformal film in a gap extends partially into the gap, covers a first portion of the inner surface of the gap, and does not cover a second portion of the inner surface of the gap, where the second portion is deeper within the gap than the first portion.

[0067] The term "substrate" generally refers to anything on which a film may be deposited.

[0068] The term "substrate support" generally refers to any structure used to support a substrate in a processing chamber during substrate processing.

[0069] The term “3D NAND” is an abbreviation for Three-Dimensional NOT AND and generally refers to a memory architecture based on NOT AND logic gates.

[0070] The term “3D NOR” is an abbreviation for three-dimensional NOT OR memory and generally refers to a memory architecture based on NOT OR logic gates.

[0071] The term "3D DRAM" is an abbreviation for three-dimensional dynamic random access memory.

[0072] Atomic layer deposition (ALD) can be used to fill gaps on a substrate. ALD involves performing one or more deposition cycles to grow a thin film in a layer-by-layer manner on the surface of a substrate. Exemplary films that can be grown using ALD include oxide films, such as silicon oxide films. Plasma enhanced ALD (PEALD) utilizes plasma to promote the deposition of films. During a PEALD oxide film deposition cycle, a film precursor gas is introduced into the process chamber and adsorbed onto the substrate as a self-limiting layer. Next, the process chamber is purged to remove excess film precursor. Next, an oxidant is introduced into the process chamber. When the oxidant is in the process chamber, a plasma is formed. The plasma forms reactive oxygen species from the oxidant. The reactive oxygen species reacts with the adsorbed film precursor layer to form an oxide film layer. Examples of oxide films that can be formed by ALD include silicon oxide (SiO2) films, silicon oxynitride (SiO x N y ) film, silicon carbide oxide (SiO x C y ) film, aluminum oxide (Al2O3) film, gallium oxide (Ga2O3) film, titanium dioxide (TiO2) film, vanadium dioxide (VO2) film, zinc oxide (ZnO) film, zirconium dioxide (ZrO2) film, hafnium dioxide (HfO2) film, and tungsten trioxide (WO3) film.

[0073] Due to the self-limiting, layer-by-layer nature of ALD film growth, ALD can be used to form highly conformal oxide films in gaps. However, in some applications, it may be desirable to partially fill the gap in a bottom-up manner. For example, a process for forming a three-dimensional (3D) integrated circuit may include depositing a stack of alternating material layers and then forming a gap in the stack of alternating material layers. In some processes, it may be desirable to use an oxide to cover layers in the lower portion of the gap below a selected depth in the gap, and not to cover layers in the upper portion of the gap above a selected depth in the gap. The term "below a selected depth" refers to an area within the gap that is farther from the gap opening than the selected depth. The term "above a selected depth" refers to an area within the gap that is closer to the gap opening than the selected depth.

[0074] Due to the conformal nature of ALD, it can be challenging to perform partial gap filling in a bottom-up manner. One approach is to deposit the inhibitor within the gap so that the inhibitor has a higher concentration on the surface within the gap above a selected depth and a lower concentration on the surface of the gap below a selected depth. This can form a concentration gradient of the inhibitor on the surface within the gap, where the inhibitor concentration decreases with increasing depth in the gap. A higher concentration of inhibitor inhibits the deposition of the oxide film more strongly than a lower concentration of inhibitor. Using an inhibitor in this manner can result in the deposition of a non-conformal oxide film with a tapered profile that is relatively thick below a selected depth and relatively thin above a selected depth. An etching process can then be performed to remove the oxide film from the sidewall surfaces above the selected depth. However, the etching process can be time consuming. In addition, the etching process may remove film material from below the selected depth, which is desired.

[0075] Thus, examples are disclosed for performing a partial gapfill process using ALD in a bottom-up manner. Briefly, a liner is deposited subconformally in a gap. The liner can be deposited to cover the surface in a first region of the gap, extending from the top of the gap to a selected depth within the gap. The surface in a second region of the gap below the selected depth is not coated with the liner. Next, an inhibitor is deposited within the gap such that a higher concentration of the inhibitor is deposited in the first region of the gap and a lower concentration of the inhibitor is deposited in the second region of the gap. The inhibitor can include a concentration gradient that decreases with increasing depth within the gap. In the region with the liner, the combination of the liner and the inhibitor can prevent the formation of an oxide film. Furthermore, in the region below the liner, the concentration gradient of the inhibitor can result in a higher PEALD oxide film deposition rate at the bottom of the gap than near the gap opening. This can result in bottom-up oxide film growth. This can also help avoid an etching step after oxide deposition, which removes the oxide deposited in the first portion of the gap. In some examples, the liner can be used alone, without the inhibitor to inhibit oxide film growth. Using a combination of an inhibitor and a liner can provide a different oxide film profile as a function of depth compared to using a liner without an inhibitor.

[0076] The depth to which the liner is deposited in the gap can be controlled by the duration of time that the RF power is applied during liner deposition.Thus, the disclosed examples can provide control over the depth to which oxide is deposited in a partial gap fill process.

[0077] The liner may comprise any suitable material that inhibits oxide film growth. In the case of silicon oxide films, an exemplary liner material is silicon nitride (Si3N4). Other examples of liner materials that can be used to inhibit silicon oxide film growth include silicon carbonitride (SiCN), silicon carbide (SiC), and silicon oxynitride (SiON). Silicon nitride can cause a nucleation delay in reactions involving silicon oxide ALD film precursors. The term "nucleation delay" generally refers to a period during which molecules are not physically and chemically adsorbed on a surface. For example, applying an inhibitor to a surface can result in a reduction in reactive surface sites for precursor / reactant adsorption. This can result in no growth or reduced growth over multiple ALD cycles. Alternatively or additionally, some inhibitory molecules may induce surface dipoles. Surface dipoles repel precursor molecules, thereby reducing physical adsorption. Silicon nitride can cause a nucleation delay in the conversion of adsorbed aminosilane precursors to silicon oxide, thereby inhibiting silicon oxide growth. Conversely, less or no nucleation delay occurs on a surface without a silicon nitride liner. When used in combination with a halogen-containing inhibitor, a silicon nitride liner can significantly prevent oxide film growth in the region within the gap that includes the liner with adsorbed inhibitor. In the second portion of the gap, where silicon nitride is not deposited, deposition of SiO2 can occur.

[0078] Figures 1A-1F The substrate structure formed in an exemplary partial gap filling process using a liner is schematically shown. The partial gap filling process includes depositing a sub-conformal layer of silicon nitride in the gap before partially filling the gap with silicon oxide. First, Figure 1A A substrate 100 is shown including a gap 102. The gap 102 can include any suitable aspect ratio. Examples include aspect ratios in the range of 1:1 to 250:1. The substrate 100 includes a stack of alternating layers of a first material 103 and a second material 104. The stack of alternating material layers can be used to form a 3D integrated circuit. Exemplary 3D integrated circuits include 3D NAND memory, 3D NOR memory, and 3D DRAM. In the case of 3D DRAM, the layers can include alternating silicon and silicon germanium (SiGe). In the case of 3D NAND memory, the layers can include alternating silicon oxide and polycrystalline silicon (polysilicon), or alternating silicon oxide and silicon nitride. Other examples of gaps include trenches, holes, and through-holes. For example, the gaps can be used to form trench isolation regions in logic devices.

[0079] Figure 1BThe substrate 100 is shown after deposition of a liner 106 comprising a subconformal layer of silicon nitride. Any suitable method can be used to deposit the liner 106. One example is PEALD. In a subconformal PEALD process, a film precursor is adsorbed onto the surface of the feature. Exemplary film precursors for forming a silicon nitride liner include silicon-containing precursors, such as aminosilanes. Next, a portion of the precursor is converted to the liner material. For example, a nitrogen-containing precursor can be introduced into the plasma to form a reactive nitrogen-containing species. The reactive nitrogen-containing species can then react with the adsorbed silicon-containing precursor to form silicon nitride. Before all of the adsorbed silicon-containing precursor is converted to silicon nitride, the plasma can be extinguished to stop the generation of the reactive nitrogen-containing species. The adsorbed silicon-containing precursor is gradually converted to silicon nitride from the opening of the gap toward the bottom of the gap. Therefore, the depth to which the liner extends into the gap is a function of the duration of the RF power.

[0080] In the depicted example, liner 106 is deposited on the surface of substrate 100 and in a first portion 110 of gap 102. First portion 110 extends from the opening of gap 102 to a selected depth 112 within the gap. Liner 106 is not deposited in a second portion 114 of the gap. Second portion extends from selected depth 112 to a bottom 116 of gap 102. Liner 106 may include any suitable thickness. Examples include to In some examples, the thickness of the liner 106 is within the range of In a further example, the thickness of the liner 106 is within the range of Compared to using a relatively thick liner, using a relatively thin liner 106 may facilitate liner removal in subsequent processing steps.

[0081] Figure 2-3 The liner is shown schematically, demonstrating the correlation between the duration of RF power and the distance the silicon nitride liner extends into the gap. Figure 2 showed that the use of relatively short RF power duration (compared to the Figure 3 ) is formed as shown in the example depicted in FIG. Figure 2 In FIG, liner 200 includes a subconformal layer of silicon nitride deposited on substrate 202 in a first portion 204 of gap 206. First portion 204 extends from a top 208 of gap 206 to a selected depth 210 within the gap. Liner 200 does not extend into a second portion 212 of gap 206. Second portion 212 extends to a bottom 214 of gap 206.

[0082] Figure 3 showed that using longer RF power duration (compared to Figure 2Example) formed by an exemplary gasket. Figure 3 In FIG, a liner 300 comprising a subconformal layer of silicon nitride is deposited on a substrate 302 and in a first portion 304 of a gap 306. The first portion 304 extends from a top 308 of the gap 306 to a selected depth 310 within the gap 306. Figure 2 The selected depth is 210, Figure 3 The selected depth 310 of the gap 306 is further away from the opening of the gap 306. The liner 300 is not deposited in the second portion 312 of the gap 306. The second portion 312 extends from the selected depth 310 to a bottom 314 of the gap 306.

[0083] During the PEALD cycle, the longer duration of RF power allows the reactive nitrogen species formed by the plasma to move deeper into the gap. It converts the film precursor on the sidewall surface deeper in the gap into a silicon nitride film. By using a relatively long RF power duration, Figure 3 The liner 300 reaches a selected depth 312, which is greater than the selected depth 312 in the gap. Figure 2 The selected depth 210 of the pad 200 is deeper.

[0084] return Figure 1C After forming liner 106, an inhibitor 120 is optionally deposited within gap 102. Inhibitor 120 is deposited onto substrate 100 under conditions that cause the inhibitor to be adsorbed at a higher concentration in first portion 110 of the gap and at a lower concentration in second portion 114 of the gap. For example, the concentration of the inhibitor deposited at selected depth 112 is greater than the concentration of the inhibitor deposited at second depth 122 within gap 102. Second depth 122 is located within second portion 114 of the gap. Second depth 122 is also further from the top of the gap than selected depth 112. The resulting concentration gradient can more strongly suppress oxide film growth within first portion 110 of gap 102 and less strongly suppress oxide film growth within second portion 114 of gap 102. Furthermore, as described above, liner 106 including adsorbed inhibitor 120 can prevent oxide growth. The combination of inhibitor 120 and liner 106, as shown in this example, can facilitate filling second portion 114 of gap 102 in a bottom-up manner.

[0085] The deposition of the inhibitor can be controlled by controlling various process conditions to form a concentration gradient of the inhibitor within the gap. Exemplary process conditions include total chamber pressure, partial pressure of the inhibitor, partial pressure of other gases (e.g., diluent gases), substrate temperature, gas flow rate, duration of inhibitor gas flow, and plasma characteristics. For example, using an in-situ plasma to deposit the inhibitor can result in a directional effect that drives the inhibitor into the gap. In some examples, the in-situ plasma can include a higher frequency component and a lower frequency component. The higher frequency component can provide activation energy to form the reactive inhibitor species. The lower frequency component can be used to direct the reactive inhibitor species toward the substrate.

[0086] In some examples, the higher frequency RF energy component may include a power in the range of 50W-6000W. Increasing the power of the high frequency component may drive the inhibitor further into the gap. The lower frequency RF energy component may also include a power in the range of 0-6500W. Increasing the power of the low frequency component may also be used to drive the inhibitor further into the gap. Increasing the suppression time, suppressant partial pressure, total chamber pressure, and suppressant flow rate also results in more suppressant being deposited deeper into the gap.

[0087] In examples utilizing silicon nitride liners, suitable inhibitors include halogen-containing inhibitors. Halogen-containing inhibitors can be chemically adsorbed onto the liner to form a halogenated surface. For example, fluorine-containing inhibitors can be chemically adsorbed onto the silicon nitride liner to form a fluorinated silicon nitride surface. Compared to an unmodified silicon nitride surface, a fluorinated silicon nitride surface can more effectively inhibit or even prevent oxide film growth. In other examples, carbon-containing inhibitors can be used. Carbon-containing inhibitors are physically adsorbed onto the substrate surface and compete with the oxidant in converting the adsorbed silicon-containing precursor to oxide. In further examples, nitrogen-containing inhibitors can be used.

[0088] In other examples, the use of an inhibitor may be omitted. For example, as described above, nucleation reactions involving aminosilanes may have a nucleation delay on silicon nitride surfaces. Therefore, for some use cases, not using an inhibitor may be sufficient to inhibit silicon oxide growth on silicon nitride liner 106.

[0089] Figure 1DDeposition of an oxide film 130 is shown in the second portion 114 of the gap 102. In some examples, the oxide film 130 comprises silicon oxide. In other examples, any other suitable oxide film may be used. Examples include silicon oxynitride, silicon oxycarbide, aluminum oxide (Al2O3), gallium oxide (Ga2O3), titanium dioxide (TiO2), vanadium dioxide (VO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), hafnium dioxide (HfO2), and tungsten trioxide (WO3). Any suitable method may be used to deposit the oxide film. Examples include TLD and PEALD. If desired, the suppressor 120 may be reapplied during one or more suppressed ALD cycles.

[0090] Oxide film growth occurs at a relatively low rate on surfaces with a higher concentration of deposition inhibitor, and at a relatively high rate on surfaces with a lower concentration of deposition inhibitor. Figure 1D As shown, the growth of oxide film 130 is relatively slow at a selected depth 112 within gap 102, and relatively fast at a second depth 122 within gap 102. Furthermore, the growth of the oxide film is completely suppressed on liner 106 including inhibitor 120. Thus, oxide film 130 fills second portion 114 of gap 102 in a bottom-up manner.

[0091] Figure 1E Substrate 100 is shown after additional growth of oxide film 130 has been performed to fill second portion 114 of gap 102. Oxide film 130 does not grow in first portion 110 of gap 102 due to liner 106. Thus, liner 106 facilitates partial gap filling of gap 102 using oxide film 130. Figure 1E Also shown is an inhibitor 120 prior to removal. In some examples, a passivation process may be used to remove the inhibitor. When using a halogen-containing inhibitor or a nitrogen-containing inhibitor, an exemplary passivation step may include exposing the inhibitor adsorbed to the substrate surface to one or more of H2 or O2. In some examples, heat and / or plasma energy may be used to promote passivation. Another exemplary passivation involves exposing the inhibitor to a plasma comprising H2 / N2 / Ar. In other examples, the inhibitor may be consumed during the ALD process. In such examples, additional suppressed ALD cycles may be used as needed to form an oxide film having a desired profile.

[0092] Figure 1FThe substrate 100 is shown after the liner 106 has been removed. The liner 106 may be removed by a suitable etching process. Examples may include dry etching and wet etching processes. For example, a fluorine-containing gas (e.g., NF3, SF6, or CF4) may be used with a plasma to remove a silicon nitride liner. In other examples, a wet etch with phosphoric acid may be used to selectively etch silicon nitride (relative to silicon oxide). As described above, in some examples, the liner 106 may include 3 to 100 nm. A relatively thin liner can facilitate removal because the etching time can be relatively short (compared to the etching time of a relatively thick liner). In other examples, the liner 106 is not removed but remains in the gap 102. Therefore, by controlling the RF power duration to control the selected depth of the liner, the gap can be partially filled to a controllable depth level in a bottom-up manner.

[0093] Figures 4A-4C An exemplary method 400 is shown for performing a bottom-up partial gap fill process to partially fill a gap on a substrate. Any suitable ALD tool may be used to perform the method 400. Exemplary ALD tool reference Figure 5 It is described below.

[0094] First reference Figure 4A Method 400 includes, at step 402, depositing a liner in a first portion of the gap and not depositing a liner in a second portion of the gap. The first portion extends from a top of the gap to a selected depth within the gap. The second portion of the gap extends from the selected depth to a bottom of the gap. In some examples, as shown in 403, the substrate includes a 3D integrated circuit. Substrate 100 is an example of a 3D integrated circuit. In other examples, the liner can be formed on any other suitable structure in an integrated circuit manufacturing process.

[0095] In some examples, the liner includes a subconformal layer of silicon nitride. In such examples, a PEALD process can be used to deposit the liner, as shown in step 404. Using PEALD to deposit the silicon nitride liner can include, in step 406, introducing a silicon-containing precursor into a processing chamber including the substrate. The silicon-containing precursor is adsorbed onto the surface in the gap on the substrate. Suitable silicon-containing precursors for forming the silicon nitride can include aminosilanes. Exemplary aminosilanes include bis(diethylamino)silane, di(isopropylamino)silane, bis(tert-butylamino)silane, (di-sec-butylamino)silane, or tris(dimethylamino)silane. In some examples, trisilylamines, halosilanes, and / or organosilanes can be used. Examples of halosilanes can include dichlorosilane (H2SiCl2), hexachlorodisilane (Si2Cl6), and diiodosilane (H2SiI2). Examples of organosilanes are listed above.

[0096] At step 408, the process chamber is purged to remove excess silicon-containing precursor. Continuing, method 400 includes, at step 410, introducing a nitrogen-containing species into the process chamber. The nitrogen-containing species is used to generate reactive nitrogen species in the plasma to convert the adsorbed silicon-containing precursor into silicon nitride. The reactive nitrogen species may include, for example, excited N2 and / or nitrogen radicals. In some examples, the nitrogen-containing species is nitrogen gas. In other examples, the nitrogen-containing species may include NH3, a mixture of nitrogen and hydrogen, or hydrazine (N2H4).

[0097] Continuing, method 400 includes, at step 412, forming a plasma for a selected duration to generate reactive nitrogen species. The reactive nitrogen species reacts with the adsorbed silicon-containing precursor to form a silicon nitride liner. Figure 2 and 3 As described above, the duration of forming the plasma can control the depth to which the silicon nitride liner extends into the gap. In some examples, forming the plasma at 413 includes applying RF power for a duration of 0.5 seconds to 60 seconds. In some examples, the duration is in the range of 1 second to 30 seconds, or even in the range of 1 second to 20 seconds. In other examples, the duration of applying RF power can be outside these ranges.

[0098] In some examples, the plasma includes a radio frequency plasma. For example, the plasma can be a capacitively coupled plasma or an inductively coupled plasma. Exemplary frequencies of radio frequency plasma include 400 MHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In other examples, a microwave plasma can be used instead of a radio frequency plasma. Furthermore, in some examples, a substrate heater is used to heat the substrate during liner deposition.

[0099] In some examples, a purge is performed after the plasma treatment of step 410 to complete the ALD cycle at step 414. Such a purge may be performed after extinguishing the plasma. In other examples, the purge may be omitted.

[0100] At step 416, a determination is made as to whether any additional ALD cycles are to be performed to form the liner. If additional ALD cycles are to be performed, method 400 returns to step 406. On the other hand, if no further ALD cycles are to be performed to form the liner, the liner deposition process ends. While the above description relates to the formation of a silicon nitride liner, other suitable liner materials may be used in other examples. Examples include silicon carbide, silicon carbonitride, and silicon oxynitride.

[0101] Next reference Figure 4BAfter depositing the liner, method 400 includes, at step 420, performing a plurality of oxide ALD cycles to deposit oxide in a second portion of the gap. The second portion of the gap extends from a selected depth to a bottom of the gap. The plurality of ALD cycles may include inhibited ALD cycles and / or non-inhibited ALD cycles.

[0102] With respect to the inhibited ALD cycle, an inhibitor may be deposited to help further inhibit the formation of an oxide film in the area where the liner is deposited. In some such examples, the combination of the liner and the inhibitor adsorbed on the liner may completely prevent the formation of an oxide film on the surface of the inhibited liner. Thus, method 400 includes, at step 422, optionally implementing an inhibited ALD cycle. The inhibited ALD cycle for depositing the oxide layer includes, at 424, introducing an inhibitor into the process chamber to deposit a greater concentration of the inhibitor at a first depth within the gap and a lesser concentration of the inhibitor at a second depth within the gap. The second depth is deeper than the first depth with respect to the opening of the gap. As shown at 426, in some examples, a plasma may be used to deposit the inhibitor. As described above, various deposition conditions may be controlled to deposit the inhibitor to have a greater concentration at the first depth and a lesser concentration at the second depth. Exemplary processing conditions that may be varied (in order to change the concentration profile of the deposited inhibitor within the gap as a function of depth in the gap) include total chamber pressure, partial pressure of the inhibitor, partial pressures of other gases (e.g., diluent gases), substrate temperature, gas flow rates, inhibitor gas flow duration, and plasma characteristics.

[0103] Any suitable inhibitor may be used. Examples include halogen-containing inhibitors, as shown at 428. Suitable halogen-containing precursors may include fluorine-containing inhibitors, as shown at 430. Exemplary fluorine inhibitors may include F2, HF, BF3, PF3, NF3, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides (e.g., SF4 or SF6), or interhalogen compounds (e.g., ClF3 or ClF5). Exemplary fluorocarbons include CF4 and C2F6. In other examples, chlorine-containing precursors, bromine-containing precursors, or iodine-containing precursors may be used. Examples of chlorine-containing precursors include chalcogen chlorides, such as S2Cl2 or SCl2. In some examples, interhalogen compounds may be used. The term "interhalogen" generally refers to a molecule containing two or more different halogen atoms. In other examples, nitrogen-containing inhibitors may be used. Examples of nitrogen-containing inhibitors include N2, NH3, nitrogen and hydrogen mixtures, amines, diamines, and amino alcohols. In still other examples, carbon-containing inhibitors may be used. Examples include alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alcohols, aldehydes, esters, ethers, ketones, aldehydes, alkyl halides, alkylamines, or alkyldiamines that are in the gas phase under the processing conditions.

[0104] The plasma converts the inhibitor into a reactive inhibitor species. The reactive inhibitor species can adsorb to a surface on the substrate. For example, the inhibitor can adsorb to a pad, as shown at 431. In other examples, the inhibitor is deposited in the absence of a plasma. Examples of inhibitors that can be deposited in the absence of a plasma include carbon-containing inhibitors. As described above, carbon-containing inhibitors can physically adsorb to the substrate surface. During oxidation of the silicon-containing precursor, the physically adsorbed carbon-containing inhibitor competes with the silicon-containing precursor for oxygen. Therefore, a higher concentration of the carbon-containing precursor reduces the amount of oxygen available to oxidize the silicon-containing precursor.

[0105] Continuing, at 432, the inhibited ALD cycle 422 includes introducing an oxide film precursor into the process chamber. Exemplary film precursors for forming silicon-containing films using PEALD may include materials having the following general structure: R1, R2, and R3 may be the same or different substituents, and may include silane, silane alkoxy, amine, halide, hydrogen, or organic groups such as alkylamine, alkoxy, alkyl, alkenyl, alkynyl, and aromatic groups.

[0106] Exemplary silicon-containing precursors include silane, polysilane (H3Si-(SiH2) n -SiH3), where n≥0, such as disilane, trisilane, tetrasilane, and trisilylamine.

[0107] In some examples, the silicon-containing precursor is an alkoxysilane. The alkoxysilanes that can be used include: x -Si-(OR) y An alkoxysilane wherein x=1-3, x+y=4, and each R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aromatic group; and H x (RO) y -Si-Si-(OR) y H x , is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aromatic group.

[0108] Examples of silicon-containing precursors include tetraethylorthosilicate, tetramethoxysilane, methylsilane, trimethylsilane, ethylsilane, butasilane, pentasilane, octylsilane, heptylsilane, hexasilane, cyclotetrasilane, cycloheptylsilane, cyclohexasilane, cyclooctylsilane, cyclopentasilane, 1,4-dioxa-2,3,5,6-tetrasilacyclohexane, diethoxymethylsilane, diethoxysilane, dimethoxymethylsilane, dimethoxysilane, methyldiethoxysilane, methyldimethoxysilane, tert-butoxydisilane, triethoxysilane, and trimethoxysilane.

[0109] In some examples, the silicon-containing precursor can be a siloxane. Exemplary siloxanes include octamethylcyclotetrasiloxane, octamethoxydodecylsiloxane, tetramethylcyclotetrasiloxane, triethoxysiloxane, and tetraoxymethylcyclotetrasiloxane.

[0110] In some examples, the silicon-containing precursor may be an aminosilane. Exemplary aminosilanes include bis(diethylamino)silane, di(isopropylamino)silane, bis(tert-butylamino)silane, (di-sec-butylamino)silane, or tris(dimethylamino)silane. The aminosilane precursor may have the following general formula: x -Si-(NR) y , wherein x=1-3, x+y=4, and R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aromatic group, or a hydride group.

[0111] In other examples, the oxide film precursor may include a metal-containing precursor. Examples of metal-containing precursors include aluminum-containing precursors, gallium-containing precursors, titanium-containing precursors, vanadium-containing precursors, zinc-containing precursors, zirconium-containing precursors, hafnium-containing precursors, and tungsten-containing precursors.

[0112] At step 434, the processing chamber is purged to remove excess oxide film precursor. Next, the suppressed ALD cycle 422 includes, at 436, introducing an oxidant into the processing chamber. Suitable oxidants include O2, O3, H2O, H2O2, N2O, and other nitrogen oxides. At 438, the suppressed ALD cycle 422 includes reacting the adsorbed oxide film precursor with the oxidant to form an oxide film layer on the substrate. In examples where PEALD is used to form an oxide film, a plasma is used to react the oxide film precursor with the oxidant. For example, an RF power source can be used to form a plasma containing the oxidant to carry out the reaction. The RF power source can operate at any suitable frequency and power. Examples include those listed above. The oxidant can be converted into an oxygen-containing reactive species by the plasma. The oxygen-containing reactive species can then react with the adsorbed oxide film precursor monolayer to form an oxide film layer on the substrate. Suitable oxide films include silicon dioxide films, silicon oxynitride films, and silicon oxycarbide films. The oxide film grows non-conformally due to the inhibitor deposited at 424. Thus, a relatively thicker oxide film layer may form on the surface at a second depth in the gap (corresponding to a lower concentration of inhibitor). Likewise, a relatively thinner oxide film layer may form on the surface at a selected depth in the gap (corresponding to a higher concentration of inhibitor).

[0113] After the oxide film precursor reacts with the oxidant, the inhibited ALD cycle 422 includes purging the process chamber at 440. The inhibited ALD cycle 422 may optionally include deactivating the inhibitor at 442.

[0114] Next reference Figure 4C , method 400 optionally includes non-inhibited ALD cycles 444. In examples where the use of an inhibitor is omitted, all of the plurality of ALD cycles may include non-inhibited ALD cycles 444. In examples where an inhibitor is used, a subset of the plurality of ALD cycles may be non-inhibited ALD cycles 444, e.g., where the inhibitor is not completely consumed in each ALD cycle.

[0115] An exemplary non-inhibited ALD cycle 444 is as follows. At 446, non-inhibited ALD cycle 444 includes introducing an oxide film precursor into the process chamber. As described above with respect to inhibited ALD cycle 422, suitable oxide film precursors for forming silicon-containing oxide films may include polysilanes, aminosilanes, halosilanes, siloxanes, and organosilanes. In other examples, the oxide film precursor may include a metal-containing precursor. Exemplary metal-containing precursors are described above. Next, at step 448, the process chamber is purged to remove excess oxide film precursor.

[0116] Continuing, at 450, the non-inhibited ALD cycle 444 includes introducing an oxidant into the process chamber. Any suitable oxidant capable of reacting with the oxide film precursor to form an oxide film may be used. Suitable oxidants include O2, O3, H2O, and H2O2.

[0117] At 452, the non-inhibited ALD cycle 444 includes, at step 452, reacting an oxide film precursor with an oxidant to form an oxide film layer on the substrate. In examples utilizing PEALD, a plasma may be used to form a reactive oxidant species that reacts with the film precursor. In the case where the liner is deposited in a first portion of the gap, oxide film formation in the first portion of the gap is inhibited and / or prevented. On the other hand, oxide film growth occurs in a second portion of the gap that does not have a liner. In other examples, TALD may be used to implement the ALD cycle. In such examples, the reaction of step 452 is implemented using thermal energy. The substrate may also be heated during the PEALD cycle. In some examples, after reacting the oxide to complete the ALD cycle, a purge is implemented at step 454. In other examples, the purge may be omitted.

[0118] Continuing, at step 456, after optionally performing either the inhibited ALD cycle 422 or the non-inhibited ALD cycle 446, method 400 includes determining whether another ALD cycle is to be performed. If it is determined that another ALD cycle is not to be performed, the bottom-up oxide deposition cycle of method 400 ends. On the other hand, if it is determined that another ALD cycle is to be performed, method 400 includes, at step 458, determining whether an inhibited ALD cycle is to be performed. If the next cycle is an inhibited ALD cycle, method 400 includes, at 460, optionally causing additional inhibitor to adsorb to the substrate (as described with reference to step 424). Method 400 then returns to step 432. If the next cycle is a non-inhibited ALD cycle, method 400 returns to 446.

[0119] After the bottom-up oxide deposition is complete, method 400 optionally includes, at step 462, passivating any inhibitor remaining on the substrate. Method 400 further optionally includes, at step 464, removing the liner. Any suitable etching method may be used to remove the liner. Examples may include wet etching and dry etching processes. Because the liner may be thin (e.g., to ), so the etching time can be relatively short. In other examples, the removal of the liner can be omitted.

[0120] Figure 5A schematic diagram of an exemplary ALD tool 500 for performing atomic layer deposition is shown. The ALD tool 500 is configured as a PEALD tool. The ALD tool 500 is a tool that can implement the above reference Figures 1A to 4C Examples of processing tools for the disclosed methods. In some examples, the ALD tool 500 can be used to deposit both the liner and the oxide film. In other examples, different tools can be used to perform the liner deposition and the oxide film deposition. In other examples, the liner and / or oxide film according to the disclosed examples can be deposited in a TALD chamber.

[0121] The ALD tool 500 includes a process chamber 502 and a substrate support 504 within the process chamber. The substrate support 504 is configured to support a substrate 506 disposed within the process chamber 502. The substrate support 504 may include a pedestal, a chuck, and / or any other suitable structure. The substrate support 504 includes a substrate heater 508. In other examples, the heater may be omitted or located elsewhere within the process chamber 502.

[0122] The ALD tool 500 also includes a showerhead 510. In other examples, the processing tool may include a nozzle or other device for introducing gases into the processing chamber 502 instead of or in addition to the showerhead. The ALD tool 500 also includes flow control hardware 512. The flow control hardware 512 connects one or more process gas sources to the processing chamber. In the depicted example, the flow control hardware 512 connects a silicon-containing precursor source 514, a nitrogen source, an oxide film precursor source 516, an oxidant source 518, a suppressant source 520, and an inert gas source 522 to the processing chamber. The flow control hardware 512 may include any suitable components. Examples include mass flow controllers, valves, and conduits.

[0123] The silicon-containing precursor source 514 includes any suitable silicon-containing precursor for forming a subconformal layer of silicon nitride. Examples include aminosilanes, such as bis(diethylamino)silane, di(isopropylamino)silane, bis(tert-butylamino)silane, (di-sec-butylamino)silane, or tris(dimethylamino)silane. Aminosilane precursors include the following: x -Si-(NR) y , wherein x=1-3, x+y=4, and R is a substituted or unsubstituted alkyl, alkenyl, alkynyl, aromatic group, or hydride group. Suitable silicon-containing precursors may also include polysilanes, halosilanes, and organosilanes.

[0124] Nitrogen source 515 includes a nitrogen source for forming a plasma containing radical nitrogen species. Such a plasma can be used, for example, to activate a silicon-containing precursor adsorbed on substrate 506 to form a silicon nitride film in a first portion of the gap on the substrate. Exemplary nitrogen sources include N2, NH3, and N2H4.

[0125] The oxide film precursor source 516 may include any suitable oxide film precursor that forms an oxide film when reacted with an oxidant. Exemplary silicon-containing oxide films include silicon dioxide, silicon oxynitride, and silicon oxycarbide. Exemplary silicon-containing precursors for such films include those described above with reference to Figure 4B and 4C In some examples, the same silicon-containing precursor can be used to provide the precursors for both the silicon nitride liner and the silicon oxide film.

[0126] The oxidant source 518 includes any suitable substance that can react with the silicon-containing precursor to form silicon oxide. Examples include O2, O3, H2O, and H2O2, N2O, other nitrogen oxides, and mixtures of two or more thereof.

[0127] The inhibitor source 520 includes any suitable inhibitor that can be adsorbed onto the substrate and inhibit the growth of the oxide film during the ALD process. Suitable inhibitors may include halogen-containing inhibitors (e.g., fluorine-containing inhibitors, chlorine-containing inhibitors, bromine-containing inhibitors, iodine-containing inhibitors, interhalogen compounds), nitrogen-containing inhibitors, and carbon-containing inhibitors. Suitable fluorine-containing inhibitors may include F2, HF, BF3, PF3, NF3, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides, and interhalogen compounds that are in the gas phase under the process conditions. Examples of chlorofluorocarbons include CCl3F. Examples of fluorocarbons include CF4 and C2F6. Examples of hydrofluorocarbons include difluoromethane (CH2F2). Examples of chalcogen fluorides include SF4 and SF6. Examples of chalcogen chlorides include S2Cl2 and SCl2. Examples of interhalogen compounds include ClF3 and ClF5. Further examples of halogen-containing inhibitors may include Cl2, HCl, CCl4, Br2, HBr, I2, HI, and C2H4I2.

[0128] Suitable nitrogen-containing inhibitors may include N2, NH3, nitrogen and hydrogen mixtures, amines, diamines, and amino alcohols.

[0129] Suitable carbon-containing inhibitors may include compounds that can be in the gas phase under the processing conditions, physically adsorbed to the substrate 506, and oxidized by the oxidant to form a gas-phase product. Exemplary carbon-containing inhibitors suitable for non-conformal film deposition may include various alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alcohols, aldehydes, esters, ethers, ketones, aldehydes, alkyl halides, alkylamines, and alkyldiamines. More specific examples of carbon-containing inhibitors include those listed above.

[0130] Inert gas source 522 may include any suitable inert gas. Examples include helium, neon, argon, krypton, xenon, and nitrogen. In some examples, one or more additional purge gas sources may be included, each providing a different purge gas. In other embodiments, inert gas source 522 may be omitted, and nitrogen source 515 may be used to supply the inert gas.

[0131] Flow control hardware 512 can be controlled to flow gases from a silicon-containing precursor source 514, a nitrogen source 515, an oxide film precursor source 516, an oxidizer source 518, a suppressor source 520, and an inert gas source 522 through the showerhead 510 into the processing chamber 502. The flow control hardware 512 can include one or more valves that are controllable to fluidly connect a selected one or more gas sources to the showerhead 510. The flow control hardware 512 can also include one or more mass flow controllers or other controllers for controlling the mass flow of gases.

[0132] The ALD tool 500 also includes an exhaust system 524. The exhaust system 524 is configured to exhaust gases from the processing chamber 502. The exhaust system 524 can include any suitable hardware, including one or more rough vacuum pumps and one or more high vacuum pumps.

[0133] The ALD tool 500 also includes an RF power source 526 electrically connected to the substrate support 504. The RF power source 526 is configured to form a plasma. When the adsorbed silicon-containing precursor is reacted with nitrogen, the RF power source 526 can form a plasma containing nitrogen. Similarly, when the adsorbed oxide film precursor is reacted with an oxidant, the RF power source 526 can form a plasma containing an oxidant. In some examples, a halogen-containing inhibitor or a nitrogen-containing inhibitor is deposited on the substrate by forming a plasma containing an inhibitor. In this example, the showerhead 510 is configured as a grounded opposite electrode. In other examples, the RF power source 526 can supply RF power to the showerhead 510, or other appropriate electrode structures.

[0134] The ALD tool 500 also includes a matching network 528 for impedance matching of the RF power source 526. The RF power source 526 can be configured to provide RF energy having any suitable frequency and power. Exemplary frequencies include 400 kHz, 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the RF power source 526 is configured to operate at a plurality of different frequencies and / or powers. Examples of lower frequencies include frequencies below 3 MHz. The lower frequency RF energy component may include a power in the range of 0-6500 W. Examples of suitable high frequency RF power include frequencies in the range of 3 MHz to 300 MHz. The higher frequency RF energy component may include a power in the range of 50 W to 6000 W. As described above, the duration of applying the RF power can control the extent to which the liner deposited on the substrate 506 extends into the gap.

[0135] The controller 530 is operably coupled to the substrate heater 508, the flow control hardware 512, the exhaust system 524, and the RF power source 526. The controller 530 is configured to control various functions of the ALD tool 500 to perform a thin film deposition process, such as an ALD process. For example, the controller 530 is configured to operate the substrate heater 508 to heat the substrate to a desired temperature. The controller 530 is also configured to operate the flow control hardware 512 to cause a selected gas or gas mixture to flow into the process chamber 502 at a selected rate. The controller 530 is also configured to operate the exhaust system 524 to remove gases from the process chamber 502. The controller 530 may, for example, control the exhaust system 524 and / or the flow control hardware 512 to purge the process chamber 502. The controller 530 is configured to operate the RF power source 526 for a selected duration to form a plasma, as well as to control any other suitable functions of the ALD tool 500. The controller 530 may include any suitable computing system. Exemplary Computing System Reference Figure 6 It is described below.

[0136] In some embodiments, the methods and processes described herein may be incorporated into a computing system of one or more computing devices. Specifically, such methods and processes may be implemented as a computer application or service, an application programming interface (API), a library, and / or other computer program products.

[0137] Figure 6 A non-limiting embodiment of a computing system 600 is schematically shown, which can implement one or more of the methods and processes described above. Computing system 600 is shown in simplified form. Computing system 600 can take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network-accessible server computers. Controller 530 is an example of computing system 600.

[0138] The computing system 600 includes a logic machine 602 and a storage machine 604. The computing system 600 may optionally include a display subsystem 606, an input subsystem 608, a communication subsystem 610, and / or Figure 6 Other parts not shown.

[0139] Logic machine 602 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 achieve a desired result.

[0140] The logic machine may include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. The processors of the logic machine may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and / or distributed processing. The various components of the logic machine may optionally be distributed across two or more separate devices that may be remotely located and / or configured for coordinated processing. Various aspects of the logic machine may be virtualized and executed by a remotely accessible, networked computing device configured in a cloud computing configuration.

[0141] The storage machine 604 includes one or more physical devices configured to store instructions 612 that can be executed by a logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of the storage machine 604 can be transformed—for example, to store different data.

[0142] The storage 604 may include removable and / or internal devices. The storage 604 may include optical storage (e.g., CD, DVD, HD-DVD, Blu-ray disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic storage (e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.). The storage 604 may include volatile, non-volatile, dynamic, static, read / write, read-only, random access, sequential access, location addressable, file addressable, and / or content addressable devices.

[0143] It should be understood that storage 604 comprises one or more physical devices. However, alternatively, aspects of the instructions described herein may be propagated via a communication medium (eg, electromagnetic signals, optical signals, etc.) that is not held for a finite duration by a physical device.

[0144] Aspects of the logic machine 602 and the memory machine 604 may be integrated together into one or more hardware logic components. For example, such hardware logic components may include field programmable gate arrays (FPGAs), program and application specific integrated circuits (PASIC / ASICs), program and application specific standard products (PSSP / ASSPs), systems on chips (SOCs), and complex programmable logic devices (CPLDs).

[0145] When included, display subsystem 606 can be used to present the visual representation of the data preserved by storage machine 604. This visual representation can take the form of a graphical user interface (GUI). Because the methods and processes described herein have changed the data held by the storage machine, and therefore changed the state of the storage machine, the state of display subsystem 606 can also be converted to visually represent the change of the underlying data. Display subsystem 606 can include one or more display devices using almost any type of technology. Such display device can be combined with the logic machine 602 and / or storage machine 604 in a shared cabinet (a shared enclosure), or such display device can be a peripheral display device.

[0146] When included, the input subsystem 608 may include or interact with one or more user input devices (e.g., a keyboard, mouse, or touch screen). In some embodiments, the input subsystem may include or interact with selected natural user input (NUI) components. Such components may be integrated or peripheral, and the conversion and / or processing of input actions may be handled on-board or off-board. Exemplary NUI components may include microphones for voice and / or sound recognition, and infrared, color, stereo, and / or depth cameras for machine vision and / or gesture recognition.

[0147] When included, the communication subsystem 610 can be configured to communicatively couple the computing system 600 with one or more other computing devices. The communication subsystem 610 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 to communicate using a wireless telephone network, or a wired or wireless local area network or wide area network. In some embodiments, the communication subsystem can allow the computing system 600 to send messages to and / or receive messages from other devices over a network such as the Internet.

[0148] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific one or more embodiments or examples should not be considered as restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown and / or described can be performed in the order shown and / or described, in other orders, in parallel or omitted. Equally, the order of the above-mentioned processing can be changed.

[0149] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations 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

1. A method for partially filling a gap in a substrate, the substrate being disposed in a processing chamber, the method comprising: depositing a subconformal layer of silicon nitride in a first portion of the gap and not in a second portion of the gap, the first portion extending from a top of the gap to a selected depth within the gap and the second portion extending from the selected depth to a bottom of the gap; as well as performing a plurality of atomic layer deposition (ALD) cycles to deposit a silicon-containing oxide in the second portion of the gap, an ALD cycle of the one or more ALD cycles comprising: exposing the substrate to a silicon-containing precursor so that the silicon-containing precursor adsorbs to the surface in the second portion of the gap, and The silicon-containing precursor is reacted with an oxidant to deposit the silicon-containing oxide on the surface in the second portion of the gap.

2. The method of claim 1 , wherein the one or more ALD cycles comprise: The substrate is exposed to an inhibitor under conditions configured to deposit the inhibitor into the gap such that a concentration of the inhibitor deposited at a first depth within the gap is greater than a concentration of the inhibitor deposited at a second depth within the gap, the second depth being within the second portion of the gap and further from the top of the gap than the first depth.

3. The method of claim 2, wherein exposing the substrate to the inhibitor comprises: The substrate is exposed to a halogen-containing inhibitor.

4. The method of claim 3, wherein the halogen-containing inhibitor comprises one or more of molecular fluorine, hydrogen fluoride, boron trifluoride, phosphorus trifluoride, nitrogen trifluoride, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides, chalcogen chlorides, or interhalogen compounds.

5. The method according to claim 1, further comprising: After depositing the silicon-containing oxide, the silicon nitride subconformal layer is removed from the first portion of the gap.

6. The method of claim 1 , wherein depositing the silicon nitride sub-conformal layer comprises: exposing the substrate to one or more of a halosilane precursor or an aminosilane precursor; purging the process chamber; and forming a plasma containing reactive nitrogen species.

7. The method of claim 6, wherein forming the plasma comprises: The plasma is formed for a duration in the range of 0.5 to 60 seconds. 8 . The method of claim 1 , wherein the substrate comprises a stack of alternating layers of silicon and silicon germanium, a stack of alternating layers of polysilicon and silicon oxide, or a stack of alternating layers of silicon nitride and silicon oxide.

9. The method of claim 1, wherein the gap comprises a trench for forming a trench isolation region in a logic device.

10. A method for processing a substrate comprising a gap, the method comprising: depositing a liner in a first portion of the gap and not depositing the liner in a second portion of the gap, the first portion extending from a top of the gap to a selected depth within the gap, the second portion extending from the selected depth to a bottom of the gap; as well as A plurality of atomic layer deposition (ALD) cycles are performed to deposit a silicon-containing oxide in the second portion of the gap, an ALD cycle in the plurality of ALD cycles comprising exposing the substrate to an inhibitor under conditions configured to deposit the inhibitor into the gap such that a concentration of the inhibitor deposited at a first depth is greater than a concentration of the inhibitor deposited at a second depth within the gap, the second depth being within the second portion of the gap and further from the top of the gap than the first depth.

11. The method according to claim 10, further comprising: The liner is removed from the first portion of the gap.

12. The method of claim 10, wherein depositing the liner comprises: A silicon nitride liner is deposited.

13. The method of claim 10, wherein depositing the liner comprises: Plasma is used to deposit the liner.

14. The method of claim 10, wherein the ALD cycle in the plurality of ALD cycles further comprises: The substrate is exposed to a silicon-containing precursor to allow the silicon-containing precursor to adsorb onto the substrate and then oxidize the silicon-containing precursor.

15. The method according to claim 10, further comprising: Omitting an ALD cycle in which the substrate is exposed to the inhibitor is performed in the plurality of ALD cycles.

16. The method of claim 10, wherein the inhibitor comprises one or more of molecular fluorine, hydrogen fluoride, boron trifluoride, phosphorus trifluoride, nitrogen trifluoride, chlorofluorocarbons, fluorocarbons, hydrofluorocarbons, chalcogen fluorides, chalcogen chlorides, or interhalogen compounds.

17. A structure formed on a substrate in an integrated circuit manufacturing process, the structure comprising: gap; a silicon nitride film disposed within a first portion of the gap, the first portion extending from an opening of the gap to a selected depth within the gap; as well as An oxide film is formed within the gap, the oxide film at least partially filling a second portion of the gap, the second portion of the gap extending from the selected depth to a bottom of the gap.

18. The structure of claim 17 wherein the silicon nitride film comprises a halogenated surface.

19. The structure of claim 17, wherein the structure is part of a three-dimensional memory structure.

20. The structure of claim 17 wherein the silicon nitride film is included in The thickness is within the range of .

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